introduction to process technology

Introduction to ProcessTechnology

Third Edition

Charles E.Thomas

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Introduction to Process Technology,

Third Edition

Author: Charles E. Thomas

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Preface...........................................................................................................................xi

Chapter 1 History of the Chemical Processing Industry ..........................1

Key Terms ..............................................................................................................2

1.1 History of the Chemical Processing Industry .........................................................3

1.2 Current Issues and Trends ...................................................................................14

1.3 Working in the Chemical Processing Industry .....................................................17

1.4 College Programs for Process Technology ..........................................................20

1.5 Your Career as a Process Technician ..................................................................24

1.6 Careers in the Chemical Processing Industry......................................................26

1.7 Roles and Responsibilities of a Process Technician ............................................29

1.8 Regulatory Agencies............................................................................................34

1.9 The Work Environment.........................................................................................37

Summary..............................................................................................................38

Chapter 1 Review Questions ...............................................................................40

Chapter 2 Introduction to Process Technology ..........................................41

Key Terms ............................................................................................................42

2.1 Introduction to Process Technology .....................................................................43

2.2 Safety, Health, and Environment..........................................................................47

2.3 The Principles of Quality Control .........................................................................50

2.4 Instrumentation and Process Control...................................................................51

2.5 Process Equipment..............................................................................................53

2.6 Process Systems .................................................................................................55

2.7 Process Operations..............................................................................................57

2.8 Troubleshooting....................................................................................................60

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2.9 Applied General Chemistry and Physics..............................................................63

2.10 College Math........................................................................................................65

Summary..............................................................................................................66


Chapter 3 Safety, Health, and Environment................................................69

Key Terms ............................................................................................................70

3.1 Safety, Health, and Environment Overview..........................................................71

3.2 Basic Safety Principles.........................................................................................72

3.3 Occupational Safety and Health Act ....................................................................73

3.4 The PSM Standard ..............................................................................................74

3.5 The Hazard Communication Program..................................................................74

3.6 Safe Handling, Storage, and Transportation of Hazardous Chemicals ................77

3.7 Physical Hazards Associated with Chemicals......................................................77

3.8 Health Hazards Associated with Chemicals ........................................................78

3.9 Material Safety Data Sheets ................................................................................79

3.10 Toxicology.............................................................................................................79

3.11 Respiratory Protection Programs.........................................................................79

3.12 Personal Protective Equipment ............................................................................80

3.13 Emergency Response..........................................................................................80

3.14 Plant Permit System.............................................................................................81

3.15 Classification of Fires and Fire Extinguishers ......................................................82

3.16 HAZWOPER ........................................................................................................82

3.17 Hearing Conservation and Industrial Noise .........................................................83

3.18 Department of Transportation ..............................................................................84

Summary..............................................................................................................84


Chapter 4 Applied Physics One ........................................................................87

Key Terms ............................................................................................................88

4.1 Basic Principles of Pressure ................................................................................89

4.2 Heat, Heat Transfer, and Temperature .................................................................99

4.3 Fluid Flow...........................................................................................................100

4.4 Basic Math for Process Technicians...................................................................104

Summary............................................................................................................109

Chapter 4 Review Questions .............................................................................112

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Contents

Chapter 5 Equipment One .................................................................................113

Key Terms ..........................................................................................................114

5.1 Basic Hand Tools ...............................................................................................114

5.2 Valves.................................................................................................................115

5.3 Piping and Storage Tanks ..................................................................................121

5.4 Pumps................................................................................................................124

5.5 Compressors......................................................................................................129

5.6 Steam Turbines ..................................................................................................132

5.7 Gas Turbines ......................................................................................................133

5.8 Electricity and Motors.........................................................................................134

5.9 Equipment Lubrication, Bearings, and Seals .....................................................135

5.10 Steam Traps .......................................................................................................137

Summary............................................................................................................138


Chapter 6 Equipment Two..................................................................................141

Key Terms ..........................................................................................................142

6.1 Heat Exchangers ...............................................................................................142

6.2 Cooling Towers...................................................................................................147

6.3 Boilers (Steam Generation)................................................................................149

6.4 Furnaces ............................................................................................................151

6.5 Reactors.............................................................................................................154

6.6 Distillation...........................................................................................................157

6.7 Separators..........................................................................................................161

Summary............................................................................................................162


Chapter 7 Process Instrumentation One ....................................................167

Key Terms ..........................................................................................................168

7.1 Introduction to Process Instruments ..................................................................168

7.2 Symbols and Diagrams......................................................................................173

7.3 Process Diagrams..............................................................................................182

7.4 Interlocks and Permissives ................................................................................184

7.5 P&ID Components .............................................................................................186

Summary............................................................................................................191


Contents

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Chapter 8 Process Instrumentation Two .....................................................193

Key Terms ..........................................................................................................194

8.1 Basic Elements of a Control Loop......................................................................195

8.2 Process Variables and Control Loops ................................................................196

8.3 Primary Elements and Sensors .........................................................................197

8.4 Transmitters and Control Loops .........................................................................197

8.5 Controllers and Control Modes ..........................................................................200

8.6 Final Control Elements and Control Loops ........................................................202

Summary............................................................................................................203


Chapter 9 Process Technology—Systems One ........................................207

Key Terms ..........................................................................................................208

9.1 Pump System.....................................................................................................208

9.2 Compressor System ..........................................................................................208

9.3 Electrical System ...............................................................................................212

9.4 Lubrication System ............................................................................................213

9.5 Hydraulic System ...............................................................................................213

9.6 Heat Exchanger System ....................................................................................214

9.7 Cooling-Tower System .......................................................................................214

9.8 Steam-Generation System (Boilers) ..................................................................216

9.9 Furnace System.................................................................................................218

Summary............................................................................................................221


Chapter 10 Process Technology—Systems Two ......................................225

Key Terms ..........................................................................................................226

10.1 Reactor System .................................................................................................227

10.2 Distillation System..............................................................................................228

10.3 Separation System.............................................................................................234

10.4 Pressure Relief Equipment and Flare System ...................................................235

10.5 Plastics System..................................................................................................236

10.6 Refrigeration System .........................................................................................241

10.7 Water Treatment System....................................................................................242

10.8 Utilities ...............................................................................................................243

Summary............................................................................................................243

Chapter 10 Review Questions ...........................................................................245

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Contents

Chapter 11 Industrial Processes ....................................................................247

Key Terms ..........................................................................................................248

11.1 Common Industrial Processes ...........................................................................248

11.2 Petrochemical Processes...................................................................................251

11.3 Benzene.............................................................................................................251

11.4 BTX Aromatics ...................................................................................................252

11.5 Ethylbenzene .....................................................................................................253

11.6 Ethylene Glycols ................................................................................................253

11.7 Mixed Xylenes....................................................................................................253

11.8 Olefins................................................................................................................255

11.9 Paraxylenes .......................................................................................................255

11.10 Polyethylene.......................................................................................................255

11.11 Xylene Isomerization..........................................................................................255

11.12 Ethylene .............................................................................................................256

11.13 Refining Processes ............................................................................................256

11.14 Alkylation............................................................................................................256

11.15 Fluid Catalytic Cracking .....................................................................................257

11.16 Hydrodesulfurization ..........................................................................................258

11.17 Hydrocracking ....................................................................................................259

11.18 Fluid Coking .......................................................................................................260

11.19 Catalytic Reforming............................................................................................260

11.20 Crude Distillation................................................................................................260

Summary............................................................................................................262


Chapter 12 Process Technology Operations .............................................265

Key Terms ..........................................................................................................266

12.1 Overview of Process ..........................................................................................266

12.2 Pilot Plant Operations ........................................................................................266

12.3 Process Control Instrumentation........................................................................272

12.4 Safety and Quality Control .................................................................................274

12.5 Bench-Top Operations .......................................................................................276

12.6 Operating Procedures........................................................................................276

12.7 Self-Directed Work Teams..................................................................................278

12.8 Walk-Through Qualification................................................................................278

Summary............................................................................................................278

Chapter 12 Review Questions............................................................................280

Contents

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Chapter 13 Applied General Chemistry ......................................................281

Key Terms ..........................................................................................................282

13.1 Fundamental Principles of Chemistry ................................................................283

13.2 Chemical Equations and the Periodic Table.......................................................286

13.3 Chemical Reactions ...........................................................................................291

13.4 Material Balance ................................................................................................293

13.5 Percent-by-Weight Solutions..............................................................................295

13.6 Measurements of pH..........................................................................................295

13.7 Hydrocarbons.....................................................................................................296

13.8 Applied Concepts in Chemical Processing ........................................................298

Summary............................................................................................................300


Chapter 14 Applied Physics Two ....................................................................305

Key Terms ..........................................................................................................306

14.1 Fundamental Concepts......................................................................................306

14.2 Density and Specific Gravity ..............................................................................308

14.3 Pressure in Fluids ..............................................................................................312

14.4 Complex and Simple Machines..........................................................................319

14.5 Electricity............................................................................................................323

Summary............................................................................................................328


Chapter 15 Environmental Standards ..........................................................333

Key Terms...........................................................................................................334

15.1 Air Pollution Control ...........................................................................................335

15.2 Water Pollution Control ......................................................................................336

15.3 Solid Waste Control............................................................................................336

15.4 Toxic Substances Control...................................................................................337

15.5 Emergency Response........................................................................................338

15.6 Community Right-to-Know .................................................................................338

Summary............................................................................................................339


Chapter 16 Quality Control...............................................................................341

Key Terms ..........................................................................................................342

16.1 Principles of Continuous Quality Improvement ..................................................342

16.2 Quality Improvement Cycle ................................................................................343

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Contents

16.3 Supplier-Customer Relationship.........................................................................344

16.4 Quality Tools.......................................................................................................344

16.5 Statistical Process Control .................................................................................344

16.6 Flowcharts..........................................................................................................346

16.7 Run Charts.........................................................................................................348

16.8 Cause-and-Effect (Fishbone) .............................................................................348

16.9 Pareto Charts.....................................................................................................350

16.10 Planned Experimentation...................................................................................350

16.11 Histograms or Frequency Plots ..........................................................................351

16.12 Forms for Collecting Data ..................................................................................351

16.13 Scatter Plots.......................................................................................................352

Summary............................................................................................................352


Chapter 17 Process Troubleshooting............................................................355

Key Terms ..........................................................................................................356

17.1 Troubleshooting Methods ...................................................................................356

17.2 Troubleshooting Models .....................................................................................360

17.3 Basic Equipment Troubleshooting ......................................................................362

17.4 Process Control Instrumentation........................................................................362

17.5 Pump Model .......................................................................................................363

17.6 Compressor Model.............................................................................................365

17.7 Heat Exchanger Model.......................................................................................365

17.8 Cooling-Tower Model .........................................................................................367

17.9 Boiler Model .......................................................................................................369

17.10 Furnace Model ...................................................................................................371

17.11 Reactor Model....................................................................................................374

17.12 Absorption and Stripping Model.........................................................................376

17.13 Distillation Model ................................................................................................377

17.14 Separation Model ...............................................................................................379

17.15 Multivariable Model ............................................................................................381

Summary............................................................................................................381


Chapter 18 Self-Directed Job Search...........................................................385

Key Terms ..........................................................................................................386

18.1 The Job Search..................................................................................................386

18.2 Preemployment Testing......................................................................................392

Contents

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18.3 Work Experience................................................................................................392

Summary............................................................................................................393


Chapter 19 Applied General Chemistry Two .............................................395

Key Terms...........................................................................................................396

19.1 Fundamentals of Chemistry ...............................................................................396

19.2 The Periodic Table and Chemical Bonding.........................................................400

19.3 Organic Chemistry .............................................................................................403

19.4 Balancing Equations ..........................................................................................403

19.5 Petroleum Refining: Distillation...........................................................................405

19.6 Aromatic Hydrocarbons......................................................................................408

19.7 Alkenes and Alkynes..........................................................................................408

19.8 Alcohols..............................................................................................................411

Summary............................................................................................................413


Chapter 20 Chemical Process Industry Overview ...................................417

Key Terms ..........................................................................................................418

20.1 Industrial Processes...........................................................................................418

20.2 Chemical Manufacturing Petroleum Refining .....................................................419

20.3 Exploration and Production................................................................................420

20.4 Power Generation ..............................................................................................423

20.5 Water and Wastewater Treatment ......................................................................424

20.6 Mining and Mineral Processing..........................................................................426

20.7 Food and Beverage Processing .........................................................................427

20.8 Pharmaceutical Manufacturing...........................................................................428

20.9 Pulp and Paper Processing................................................................................430

Summary............................................................................................................431


Glossary.....................................................................................................................435

Index............................................................................................................................451

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Contents

The origin and standardization of the process technology program can be traced back to aseries of activities and meetings in 1996–1998, organized by educators in the Gulf Coastarea and supported by industry. The meetings were designed to officially standardize theprocess technology curriculum at the state level in Texas. The original process technologypioneers developed eight core courses and a series of physics and chemistry classes thatare the foundation for most current process technology programs. The first course identifiedin this process was “Introduction to Process Technology”; the original vision of this group wasto develop it as a survey or overview of each course in the process technology program.

This text, Introduction to Process Technology, holds to the original vision of these pioneersand is the only work that reflects the principles they articulated. The course is designed toprovide the apprentice technician with the foundation that future classes will build upon.Thistext devotes a chapter to each of these courses and provides key objectives that instructorscan use to develop lesson plans and enhance their instruction. Each chapter includesobjectives, key terms, photographs and line drawings, lecture material, summaries, andreview questions. An instructor guide is available; however, the author strongly encourageseach teacher to develop his or her own tests and learning activities.These activities can belinked to instructional videos, lab exercises, or field trips. Key topics covered in this textinclude:

• Introduction to process technology• Safety, health, and environment• Process instrumentation• Process equipment• Process systems• Quality control• Troubleshooting• Process operations• Applied general chemistry• Physics

This textbook is divided into 20 chapters, with the more difficult concepts spread over morethan one chapter. Each chapter is intended to cover the key objectives found in individual

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courses, but at a less intense level that is appropriate to the overview nature of the introductorycourse.

Over the past 15 years, process technology has become one of the most popular programs incommunity colleges and universities located in heavily industrialized areas. A variety of programsappeared virtually overnight in response to government, industry, and community needs. Asdefined in the regionally accredited process curriculum, process technology is the study andapplication of the scientific principles (math, physics, chemistry) associated with the operation(instruments, equipment, systems, troubleshooting) and maintenance (safety, quality) of thechemical processing industry.

Process technicians can be found working in petrochemical and refinery operations, the pharma-ceutical industry, food processing, paper and pulp manufacturing, and many other areas. Thisgroup represents the fourth largest U.S. manufacturing segment.

The chemical processing industry (CPI) is currently experiencing severe shortages in skilled tech-nicians to operate plants. As the large Baby-Boomer group reaches retirement age, the CPI bracesfor a 70% to 80% employee turnover.The next three to seven years will bring massive changes aseducation levels in the United States continue to drop. The CPI is painfully aware of the changingrequirements for process technicians. New technology, rightsizing, and redistribution of technicalskills have created a new profile for this group. The term “gold collar” is being applied to the fieldof process technology, which can command incomes in the six-figure realm.

The process technician of the future will have a one-year, state-approved certificate or a two-yearAAS degree in process technology. The education needed to achieve that certification or degreewill include instruction in modern manufacturing, engineering principles, math, physics, chemistry,unit operations, safety, equipment checking, sampling, data collection, data organization, dataanalysis, troubleshooting, and operation of new process control computer systems—among otherthings. These new apprentice technicians will need good interpersonal skills, strong technical andproblem-solving skills, the ability to assimilate cutting-edge technologies quickly, and the ability toapply innovative ideas. In addition to these skills, a process technician will need to be able to han-dle conflict, look at a complex situation and see the overall picture, and communicate effectively.Exposure to these areas and experience will be gained both within technical and academicclasses and on the job.

The author would like to express his thanks to those individuals who have been involved in thedevelopment of the process technology program.

Charles E. Thomas, Ph.D.

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Preface

History of the ChemicalProcessing IndustryAfter studying this chapter, the student will be able to:

• Explain the history and development of the chemical processing industry.• Define key terms used in process technology.• List alternative fuel sources that will be used in the future.• Identify the roles and responsibilities of a process technician.• Describe batch operations, thermal cracking, fractional distillation,

and catalytic cracking.• Describe current issues and trends in the petroleum industry.• Explain the future of oil, the “Big Rollover,” and the Hubbert peak theory.• Contrast the development of the hydrocarbon industry with advances

in modern society.• List the skills required to work in the chemical industry.• Describe college programs in process technology.• Explain skills and techniques used by successful college students.• Discuss the key elements of working in a diverse workforce.• Define sexual harassment.• Describe the chemical processing industry and future trends.• Explain the responsibilities of various regulatory agencies.• Describe the process technician’s work environment.

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Key TermsBatch process—order of work in which all ingredients are added to the process up front.

Big Rollover—point at which global oil production peaks and then begins to decline.

Biogenic theory—describes how natural gas and crude oil were formed using pressure orcompression and heat on ancient organic material.

Catalytic cracking—process that uses a catalyst to separate hydrocarbons.

Chemical processing industry (CPI)—business segment composed of refinery, petrochemi-cal, paper and pulp, power generation, and food processing companies and technicians.

College programs in process technology—state-approved and regionally accredited programsthat include courses such as Introduction to Process Technology; Safety, Health, and Environ-ment; Process Instrumentation; Process Technology 1—Equipment, PT 2—Systems, and PT 3—Operations; Process Troubleshooting; Principles of Quality; and applied chemistry, physics, andbasic math.

Diversity training—identifies and reduces hidden biases between people with differences.

Estimated ultimately recoverable (EUR)—technical term describing the total amount of crudeoil that will ultimately be recovered. This number is difficult to calculate and fluctuatesfrequently. Oil reserves are typically underestimated and are adjusted as additional informationand new technology become available. Most experts believe that 1.2 trillion barrels (without oilsands) and 3.74 trillion barrels (with oil sands) reflect the world’s total endowment of oil.

Fractionating column—the central piece of equipment in a distillation system. Fractionatingcolumns separate hydrocarbons by their individual boiling points.

Future hiring trends—directions in employment; large numbers of retiring “baby boomers”will have to be replaced in the chemical processing industry.

Goal setting—establishment of reasonable, specific, measurable objectives that lead towardthe successful achievement of a goal.

Gold collar—term used to describe process technicians.

Housekeeping—maintenance of cleanliness and order; closely associated with safety in thechemical processing industry. Process technicians are required to keep their immediate areasclean.

Hubbert peak theory—describes how future world petroleum production will peak and thenbegin the process of global decline. This decline will closely match the former rate of increase,as known oil reservoirs move to exhaustion.

Industry training programs—programs whose primary focus is on mandatory safety trainingand on-the-job training; however, a number of employers’ programs still include some of thetopics covered by college process technology courses.

Lifelong learning—ongoing process of learning about new technologies and equipment.Global competition requires companies to adopt new and innovative techniques. Process tech-nicians will come into contact with learning opportunities that cannot be found anywhere else.

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Chapter 1 ● History of the Chemical Processing Industry

Predicted model of shared responsibilities—forecast that the process technician of thefuture will take over tasks and job responsibilities presently performed by engineers andchemists.

Process technician—a person who operates and maintains the complex equipment, systems,and technologies found in the chemical processing industry. Because these people work closelywith specific pieces of equipment or processes, they are commonly called boiler operators,compressor technicians, distillation technicians, refinery technicians, or wastewater operators.

Process technology—the study and application of the scientific principles (math, physics,chemistry) associated with the operation (instruments, equipment, systems, troubleshooting)and maintenance (safety, quality) of the chemical processing industry.

Sexual harassment—behavior that constitutes unwelcome sexual advances; could take theform of verbal or physical abuse or unwelcome requests for sexual favors. The behavior mayinvolve persons of the opposite sex or of the same sex; the offending conduct may run fromsupervisor to employee, student to student, employee to employee, teacher to student, and soon. (For further information on sexual harassment, see Title VII of the Civil Rights Act of 1964.)

Thermal cracking—process that uses heat and pressure to separate small hydrocarbons fromlarge ones.

Time management—a structured system that arranges an individual’s study according toprinciples governing use of time.

1.1 History of the Chemical Processing Industry

The lifeblood of modern society is found in petroleum products. Cars, planes, trains, ships, andfarm equipment all require petroleum products to operate. Approximately 85% of all hydrocarbonsmanufactured are converted into gasoline, jet fuel, diesel, heating oils, and liquefied petroleum.The remaining 15% provides the foundation (feedstock) for fertilizers, pesticides, pharmaceuticals,solvents, plastics, and many other products. It is difficult to look around our world and not see theresults of modern petroleum manufacturing. Before 1800, though, few people recognized the valueor potential of hydrocarbon processing.

PetroleumThe term petroleum combines two Latin words, petra (rock) and oleum (oil). It was first used by aGerman mineralogist named Georg Bauer (also known as Georgius Agricola) in 1556. Petroleumis a natural resource that took millions of years to develop and is traditionally found in porous rockformations in the Earth’s upper strata. The most dominant view, called the biogenic theory,describes how natural gas and crude oil were formed using pressure or compression and heat onancient organic material. The biogenic theory hypothesizes that crude oil is made up of theremains of small ocean animals and plants that died, dropped to the bottom of the shallow oceanfloor, and were covered by sediment. Over a long period, the tremendous weight of the sediment,combined with a low oxygen content and sustained temperatures around 150 degrees, formed theoil. Under these conditions, a chemical reaction occurs as carbohydrates, proteins, and other com-pounds are converted to crude oil. Natural gas forms under these same conditions if the temper-ature is maintained near 200 degrees. As the land masses shifted, the oil was forced by water intocracks, openings, and porous rocks. Crude oil normally varies from dark brown to black, althoughit occasionally appears to be green or yellowish.


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Crude oil is a mixture of hydrocarbons that vary in molecular structure and weight from region to geo-graphic region. It is mostly composed of alkanes, aromatic hydrocarbons, and cycloalkanes.The bal-ance of the compound includes nitrogen, oxygen, iron, nickel, copper, vanadium, and sulfur.Molecularcomposition also varies depending on geographic location.Typical crude oil compositions include:

• Hydrogen 10–14%• Carbon 83–87%• Sulfur 0.5–6%• Nitrogen 0.1–2% • Oxygen 0.1–1.5%• Metals <1000 parts per million (ppm)

Modern manufacturers separate these components through the distillation process. Distillationseparates the various components in a mixture by boiling point.

An astronomer named Thomas Gold used the research of a Russian, Nikolai Kudryavtsev (whoworked in the 1800s), to develop the “abiogenic theory.” Gold believed that purely inorganichydrocarbons exist naturally in the Earth, and that over time these hydrocarbons migrated upwardthrough long fracture networks into oil reservoirs. Gold discounted the biological markers found inthe hydrocarbon and attributed their presence to stone-dwelling microbial life-forms. Only a smallminority of scientists hold to this theory today. It should be mentioned, though, that modernmanufacturers have developed methods to produce hydrocarbons from inorganic materials.

Petroleum ProductsSome examples of petroleum products are asphalt (for paving), gasoline, kerosene, plastic products,carpet material, baby diapers, aspirin, lubricating oils, butane, propane, detergents, cosmetics, insec-ticides, fertilizers, wax, milk cartons, and toothpaste. It is difficult to see our culture at its present levelof technology without petroleum; however, most experts estimate that the earth’s entire oil reservesare about 1.2 trillion (short-scale) barrels without oil sands and 3.74 trillion barrels with oil sands. Pre-sent global consumption is 84.6 million barrels a day, or 30.7 billion barrels per year.The United Statesproduces 4.9 billion barrels per year and refines more than 8.5 billion barrels per year, while importingmore than 16 billion barrels per year for commercial needs. The total population of the United Statesconstitutes only 4% of the world’s population, but we use more oil than any other country. These re-serves cannot be replaced once they are used, and some projections indicate that, at our present rateof consumption, our oil reserves will be depleted during the next 38.8 years to 122.2 years.

Process technicians will find themselves operating processes that use alternate fuel sources suchas biofuels, coal, oil shale, and tar sands, nuclear energy, wind power, and hydrogen fuel cells,along with operating new technologies. Huge reserves have been located in Canada, Utah,Wyoming, and Colorado. New conservation strategies, better oil reserve projections, alternate fuelsources, and new technologies can help to extend our supply of energy. In April 2008, the UnitedStates Geological Survey released reports of a 3–4.5 billion barrel oil find in Montana and NorthDakota. The United States has the world’s largest known deposits of oil shale, which could poten-tially add 110 years to our reserves. However, significant commercial operations have yet to beimplemented, and thus these potential resources do not meet the standard for “proven reserves.”

During the past 14 years, advances in technology and massive oil finds in Russia, Colombia, andAfrica have added to global reserves. New offshore drilling techniques allow the oil industry to drill

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at depths previously considered impossible. An offshore platform in the Gulf of Mexico called the“Genesis” extends 2,600 feet to the sea floor. The surface rig extends over two and one-half foot-ball fields. The Genesis produces more than 55,000 barrels of oil and 72 million standard cubicfeet of natural gas. Although this is impressive, a consortium of oil companies led by Chevronrecently set a well in the Gulf of Mexico in waters 7,718 feet deep.

Technological advances in converting natural gas into oil could add 1.6 trillion barrels to ourreserves. This figure represents more oil than we could use in 60 years. At present, natural gas isused for home heating, cooking, and generating electricity. The technology exists to convert natu-ral gas to gasoline, kerosene, diesel, and lubricating oils, but it is still impossible to produce heavybottom products such as asphalt from natural gas. Modern natural gas plants can be constructedfor $10 billion and produce a barrel of oil for less than $20. In 2005, the cost of a barrel of oil wasbetween $50 and $60. By 2008, the price of a barrel of crude oil had skyrocketed to more than$145, with some economists projecting that it would continue to rise. By the late summer of 2008,the price of a barrel of oil had dropped to $98 per barrel, though fluctuations were occurring weeklyand even daily. Table 1–1 illustrates how oil prices have historically performed.


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Table 1–1 Illinois Basin Crude Oil Prices

2008 $140 Iraq war2007 $64.20 Iraq war2006 $58.30 Lebanon/Israel conflict; Iraq war2005 $49.81 Iraq war2004 $37.41 Iraq war2003 $27.69 Iraq war2002 $22.812001 $23.00 9/11 terrorist attack on United States2000 $27.401999 $16.55 Cutbacks on imports; reformulated gas & taxes1998 $11.91 Asian financial crisis1997 $18.971996 $20.461995 $16.751994 $15.661993 $16.741992 $19.251991 $20.191990 $23.19 Gulf war1989 $18.331988 $14.871986 $14.64 Oil price crash1985 $26.501982–1985 $28.00 OPEC attempted to set production quotas1984 $27.501983 $29.001982 $31.551981 $35.00 Iran/Iraq war1978 $14.00

The procedure for using natural gas to create gasoline starts by passing methane and oxygen overa heated catalyst. This releases the hydrogen from the carbon atom and allows it to bond with theoxygen.This reaction produces carbon monoxide and hydrogen called syn-gas, the building blocksfor the conversion process. In step two, chains of eight or more carbons are combined to formgasoline. Products produced from natural gas burn cleaner because they do not contain sulfur,nitrogen, or molecular carbon ring arrangements.

Early ContributionsThe history of the chemical processing industry (CPI) can be traced back thousands of years.The Bible reports that Noah used pitch as a building material for the Ark. In 374 CE, the ancientChinese connected more than 800 feet of bamboo poles to pipe oil into containers where it wasburned to produce salt. Ancient Chinese and Japanese illustrations and records indicate theapplication and use of natural gas for heating and lighting. Pitch was also used to build the streetsand walls of ancient Babylon. Before the first European set foot on the North or South Americancontinents, aboriginal Indians used crude oil for medicine and fuel. Around 600 CE, temples builtnear Baku, Azerbaijan, had eternal flames that burned continuously and were a source of awe forworshippers.

Jan Baptista van Helmont and John Clayton. Manufactured gas was first discovered in 1609 byJan Baptista van Helmont, a Belgian physician and chemist. Helmont noticed that when coal isheated, it produces fumes he called “gas.” Almost a century later, an Englishman named JohnClayton captured the escaping gas from heated coal in an animal bladder. Clayton continued hisexperiment by sealing the bladder, then puncturing a small hole in its side and igniting the escap-ing gas. This demonstrated a variety of new applications for natural gas.

William Murdock. In 1792, a British engineer named William Murdock used the gases fromheated coal to light his home. From 1802 to 1804, Murdock installed more than 900 gaslights inlocal cotton mills. This earned him the title “father of the gas industry.” Large-scale operationsadopted Murdock’s process and began to expand. The United States did not adopt this technol-ogy until 1817, when Baltimore, Maryland, decided to light up its streets.

William Aaron Hart. In 1821, the first natural gas well in the United States was drilled in Fredonia,New York, by a gunsmith named William Aaron Hart. Hart piped the gas from a 27-foot well tonearby buildings for use as a lighting fuel. Between 1821 and 1865, more than 300 natural gascompanies were established. In 1859, crude oil was discovered in Titusville, Pennsylvania; withthis discovery, natural gas research and production took a serious downturn from which theindustry would not rebound until 1920. Today, natural gas is frequently used for cooking, industrialand residential heating, and as an alternative fuel source.

Abraham Gesner. One of the most significant technological improvements in the petroleumindustry occurred in 1840 when Abraham Gesner, a Canadian geologist, discovered how toproduce kerosene from coal. Kerosene provided a cheap fuel source for heating and lighting andlaid the foundation for the beginning of the chemical processing industry. Unfortunately, becausecommunications and documentation were very crude, Gesner’s discovery was not widely pro-moted or known, so Samuel Kier and J. C. Booth would repeat this experiment in 1851.

James Young and Samuel Kier. By the mid-1800s, a number of chemists, educators, and inven-tors were working on useful applications for coal, shale, and crude distillation. In 1847, James

6


Young of Scotland found a way to distill coal oil from coal and shale. Around 1851, Samuel M. Kier,a Pittsburgh pharmacist, enlisted the support of J. C. Booth, a chemist, to see if kerosene or coaloil could be distilled from crude oil. The experiments were a success and found immediate appli-cation in the kerosene market. Kier also believed that oil was a cure for many illnesses.

Benjamin Sillman, Jr. In 1854, a Yale University professor named Benjamin Sillman, Jr., wasasked to analyze a barrel of salt-skimmed crude oil. Sillman suspected that each component inthe mixture had a different boiling point, and theorized that the various components of the crudemixture could be separated by distilling at different temperatures. During his experiments,Professor Sillman distilled gasoline, kerosene, and a thick, dark, waxy oil.

Ignacy Lukasiewicz. A Russian named Ignacy Lukasiewicz was the first person to create aprocess for refining kerosene from crude oil; he did so in 1852 by improving on Gesner’s coal-kerosene process. Lukasiewicz used an abundant “rock oil” resource found in the seeps nearKrosno. The first Russian refinery, built in 1861 near the productive oil fields of Baku, produced90% of the world’s oil.

Edwin Drake. In 1859, Colonel Edwin L. Drake adapted an old steam engine to fit a drill. Drakeselected a spot near Titusville, Pennsylvania, to drill for oil. Drake drilled a 69-foot well thatproduced 15 barrels to 25 barrels a day; after this success, other oil drillers set down wells. Thebeautiful Pennsylvania landscape was transformed into an industrial community of woodenderricks, roughnecks, carpenters, and unskilled labor. Oil was shipped out on wagons to wait-ing river barges for transportation to a handful of East Coast refineries. (It should be noted,though, that the first commercial oil well in North America was drilled by James Miller Williamsat Oil Springs, Ontario, Canada, in 1858.) Figure 1–1 shows an early wooden storage tank and piping.


7

Figure 1–1 Early Chemical Processing

Production was initially limited by product transportation problems and the limited number ofrefineries. The railroad attempted to offset the transportation problem by laying track down to apoint within five miles of the oil fields; however, wagons were still used to transport the productfrom the derricks to the railroad. The transport bottleneck was not relieved until 1865, when thefirst oil pipeline was built between the oil fields and the railroad station.

The Batch ProcessRefinery operation developed overnight as new oil wells were discovered. In 1860, the first refin-ery was built by William Abbott and William Barnsdall at Oil Creek. Over the next 10 years, ahundred refineries would spring up.

The basic operation could be described as a batch process (Figure 1–2). Process technicianscharged crude oil to a vessel, and the temperature was raised in steps, from 180 degrees Fahren-heit (°F) to 1,000°F. The products yielded by this process included gasoline, naphtha, kerosene,and bottom residuum. It was a common practice to treat the kerosene with caustic soda, sulfuricacid, and a water bath. The gasoline and naphtha were discarded, and the bottom product wastreated and used as a lubricant. Process technicians treated the residuum with acid and naphtha,blended it with steam-refined feedstock, and then ran it through the distillation process again.Thisfinal product was blended with brightstock and chilled. The chilled product was stored in canvasbags so that the lighter fractions could escape. Heavy petroleum greases were made by combin-ing the chilled bottom product with fatty oils and wax.

Early refiners were able to produce 11 barrels of gas from every 100 barrels of crude oil. Becauseof this low 11% yield, the entire industry began to look for ways to increase gasoline productionwithout increasing the amounts of less profitable products. Over the next 50 years, refinersincreased yields to 20%. Modern refiners are able to convert 45% of a barrel of crude oil into gaso-line using cracking processes and combining processes. Cracking processes fall into two cate-gories: thermal and catalytic. Combining processes include alkylation, polymerization, andreforming.

Near the beginning of the 20th century, technology took a large step forward. Two inventions wereabout to change the world we live in forever: the automobile and the light bulb. In 1879, Thomas A.Edison invented the electric light bulb, which slowly replaced the kerosene lamp and natural gas.Natural gas found a market in cooking and heating uses, while kerosene found a market in

8


Condenser

Drum

Heat

Tar

Liquid

Vapor

Figure 1–2 Simple Batch Process—1860

the infant aviation field. The second invention was the automobile. As the automobile industryexploded, the need for gasoline increased dramatically. In contrast, at the beginning of the 20thcentury, gasoline was considered a worthless by-product of kerosene production and was oftendumped on the ground or in local rivers and streams.

During this time, a useful application was found for the residuum or bottom product of crude dis-tillation, which could be used to produce a new product called asphalt. Asphalt was beingproduced in large quantities as crude oil production increased. Both the immensely popular bicy-cles and the newly available automobiles required bigger, better, smoother roads to travel on, andasphalt filled the bill nicely as a paving material. Soon, government-sponsored road building proj-ects were springing up in every state.

On January 10, 1901, the chemical processing industry struck the first oil gusher in North America.Located near Beaumont, Texas, the Spindletop oil field instantly gave the CPI an unlimited oilsupply. Other wells were soon discovered in Louisiana and Oklahoma.

Thermal CrackingThe Burton Process: 1913–1920. Two of the early problems with the batch process were the pooryield of gasoline (8.4 gallons from a 42-gallon barrel of crude oil) and the residuum that was leftover after each run. Early technicians were required to climb into the vessels and chip it out byhand. This procedure was dangerous, inefficient, difficult, costly, and time consuming.

Dr. William Burton was a Standard Oil of Indiana chemist who developed a process for the thermalcracking of hydrocarbons using high pressure. Cracking process is a general term used to describehow lighter hydrocarbons are separated (cracked) from heavier hydrocarbons using conventionalmethods and higher pressure.Dr.Burton was aware of some experimental studies in England that hadproduced good results using higher operating pressures. Unfortunately, the process had been con-ducted in a laboratory and not on a large commercial level. Boilermakers did not have the modernwelding technology we use today; instead, the tank seams were filled with molten metal and beateninto place.Thus, it was difficult to find a large vessel that could withstand the higher pressures neededfor thermal cracking.Burton’s process produced greater yields:70% distillates, half of which was gaso-line (14.7 gallons). Although the yields improved, the vessels still had to be cleaned out after each run.

In the Burton process (Figure 1–3), process technicians charged the vessel with 200 barrels ofcrude oil and slowly heated it to 700°F.

Fractionating ColumnsIn 1877, the United States Patent Office granted Ernest Solvay a patent for a trayed ammoniadistillation column. Over the next 50 years, significant improvements were made in hydrocarbontechnology. The first commercial fractionating column, introduced in 1917, featured a “still upona still” design (Figure 1–4). Fractional distillation relies on Raoult’s law and Dalton’s law. Raoult’slaw states that a single chemical component in a mixture will contribute to the overall vapor pres-sure in relation to the percentage of that component in the total mixture. In contrast, Dalton’s lawstates that the total vapor pressure of a mixture will be the sum of each partial pressure. As theheated crude oil flowed into the column, a fraction of the feedstock would vaporize and rise upthrough the upper stills. The heavier components would flow through the lower stills to the bottomof the column. A liquid seal that allowed the hot vapors to pass through was established on thebottom of each still. This process allowed each component in the crude oil mixture to find its place


9

10


Feed

Bottoms

Overhead

Side Stream

Vapors

Liquids

Figure 1–4 Fractionation Column—1917

RefluxCondenser

Tar

Liquid

200 barrels750° F

3 bbl gasolineper day

Stoker

Coal Firebox

Flue StackIncreasedPressure System

Vapor

Figure 1–3 Thermal Cracking—1913

in the column, where it could then be removed from the liquid seal and stored. Early fractionatingcolumns were linked together in groups of nine, with a common feed line.

Catalytic CrackingThe Houdry Process: 1936–. Eugene J. Houdry was the heir apparent to a French structural steelfirm. During World War I, he distinguished himself as a hero. If a catalyst could be found to enhance the cracking process, a higher yield could be obtained from a barrel of crude oil. As theimpending war closed in, Houdry experimented with a variety of catalysts, which are materialsdesigned to speed up a reaction without becoming part of the reaction. In catalytic cracking, acatalyst is used to enhance the reactions that separate hydrocarbons.


11

Air

Gas

Aviation Fuel

Naphtha

Recycle Stock

Feed

Steam

Compressor

Air

Steam

RX1

RX2

RX3

Boiler

Furnace

DistillationColumn

Figure 1–5 Catalytic Cracking—1936 (The Houdry Process)

Important Events

1500 Hieronymus Braunschweig publishes The Book of the Art of Distillation.

1651 John French publishes The Art of Distillation.

1800 French scientists develop modern process techniques called feed preheatingand reflux.

1830 Aeneas Coffey (Great Britain) is awarded a patent for a continuous-operateddistillation column (without trays) for whisky.

1859 Colonel Edwin L. Drake adapts an old steam engine to fit a drill and beginsdrilling for oil near Titusville, Pennsylvania.

1860 Batch operation: The first refinery is built by William Abbott and William Barnsdallat Oil Creek. Crude oil is charged to a vessel, and the temperature is raised insteps, from 180°F to 1,000°F. The products of this process include gasoline,naphtha, kerosene, and bottom residuum.

(continued)

Using a series of bench-top units, Houdry attempted to find a catalyst that would enhance the crack-ing process. He also needed to develop a procedure to burn off the carbon that formed on the cat-alyst during the reaction (Figure 1–5). Three years after the experiment started, Houdry found oneof his reactors operating within design specifications. The reactor was filled with aluminum silicate.

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Important Events (continued )

1870 John D. Rockefeller consolidates control of the oil industry and founds StandardOil Company.

1877 Ernest Solvay is granted a U.S. patent for a trayed distillation column.

1879 Thomas A. Edison invents the electric light bulb.

1896 Henry Ford designs a gasoline engine.

1901 First oil gusher: The Spindletop, Texas, oil gusher draws thousands on January 10.

1908 Middle East oil: Large oil reserves are found in Masjed Soleyman, Persia.

1913 Thermal cracking: Dr. William Burton, a Standard Oil of Indiana chemist,develops a process for cracking hydrocarbons using high pressure and heat.

1917 The first fractionating column is introduced.

1920 Gas stations open in the United States.

1936 Catalytic cracking: Eugene J. Houdry finds a catalyst, alumina silicate, thatenhances the cracking process and gives higher yields from a barrel of crude oil.

1941 Oil embargo is placed on Japan by the United States, Britain, and theNetherlands. Japan bombs Pearl Harbor in December.

1944 Germans create a new technology to convert natural gas into oil.

1969 Santa Barbara, California, oil spill sparks an early environmental movement.

1973 Arab oil embargo: United States faces gas lines for the first time since World War II.

1977 Alaskan pipeline opens.

1979 Iranian revolution: Gasoline price tops $1.00 per gallon. More gas lines.

1984 Bhopal, India, vapor release at Union Carbide plant: Thousands are injured and killed.

1989 Exxon Valdez oil release at Prince William Sound.

1989 Phillips explosion in Houston, Texas, kills 23 technicians.

1990 ARCO explosion in Houston, Texas, kills 17.

1990 Kuwait is invaded by Iraq and the first Gulf war starts; oil fields are burned.

1999 Gas prices plummet below $0.80, then rebound to more than $2.00 per gallon.

2001 The United States is attacked; war on terrorism starts.

2004 Average cost of a barrel of oil exceeds $50.

2005 BP explosion in Texas City, Texas, kills 15 and injures 180.

2006 Many economists believe that the Big Rollover occurred, as worldwideproduction rates peak at 85 million barrels a day

2008 Average cost of a barrel of crude oil exceeds $145.


13

Feed

410°F 490 510 580 615 645 665 680Steam

235°F 290 320 385 540 550540 540 540

Gas 2 3 4 5 6 7 8 9

Figure 1–6 Fractional Distillation

Modern Fractional DistillationModern refineries and chemical plants are a lot more efficient than their counterparts from 100 yearsago. Today, the process goes through different phases: the separation process, the conversionprocess, and the treatment process (Figure 1–6).

Separation Process. When crude oil is pumped out of the ground, it is desalted, treated, and senton for additional processing. This material is heated in a large industrial furnace to 385 degreesCelsius (725°F) and pumped to a fractional distillation column. Hot vapors rise in the column andcondense on the various trays while hot liquids drop down the column until they gain enoughenergy to vaporize or separate from lighter components and congregate on their designated trays.This step is referred to as the separation process.

Conversion Process. The conversion process includes vapor recovery and alkylation on the over-head light gases and gasoline lines. Reforming and aromatic recovery are used on the keroseneline. The industrial-fuels midsection of the column is still sent to the catalytic cracking section tosqueeze out every drop of light product. The bottom lines used in the production of lubricatingoils, greases, and asphalt traditionally go through solvent recovery and the crystallizationprocess.

Treatment Process. During the treatment process, each product stream is treated and blended forproduct purity. The modern distillation column produces high-octane gasoline, gasoline, jet fuel,kerosene, heating oil, diesel oil, industrial fuels, waxes, lubricating oils, greases, and asphalt.Figure 1–7 is a photograph of a series of columns used in modern distillation.

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1.2 Current Issues and Trends

As the cost of a barrel of oil crosses the $145 threshold, many economists believe the future willsee the end of cheap oil and major volatility in the oil market. Each year the production rate at theworld’s existing oil reserves drops by approximately 7%. These losses must constantly be madeup through new reserve finds and new technology. Oil prices will probably drop back to $60–$70a barrel before rising again and stabilizing between $130–$150 a barrel over the next 5 years.A number of issues and trends are anticipated to occur over the next 10 years. These include:

• The Big Rollover (when global oil production peaks, and begins to decline). Manyeconomists believe the peak occurred in 2006 or 2007 at 85 million barrels per day(mbpd). Others believe production can go as high as 110 mbpd in the near future.

• The Hubbert peak theory (when global petroleum production will peak and decline). Thepeak occurred in 2006 or 2007. It may be possible to increase production, but the exist-ing global oil powers do not intend to mount an effort to increase production. Some ex-perts believe we could increase our daily production rate from 85 to 90 million barrels.

Figure 1–7 Modern Distillation System

15

• Rapid industrialization in China and India.• Oil supply disruptions in the Middle East, Venezuela, and Nigeria.• High-tech future offshore oil exploration.• The Bakken formation in Eastern Montana and Western North Dakota. How much oil

is there? 413 billion barrels or 4 billion barrels?• Wind turbine technology increasingly used in United States.• Gas combining operations convert natural gas to heavier hydrocarbons.• Rapid change to nonhydrocarbon solutions.• Educational program advancements; AAS and BS in Process Technology become

sought-after degrees.• Many Baby Boomers retire over next 10 years and are replaced by younger workforce.• Iraq war and problems with Iran.• Worldwide push for development and use of alternative fuel sources.• Tremendous variability in price of oil, from $200 per barrel $110 per barrel.

The primary issue involves the point in time when global oil production peaks out and begins todecline. Many oil experts believe the peak has already occurred, and predict that within the next5 to 10 years it will start to decline. New oil discoveries have declined significantly over the pastfew years even with significant improvements in exploration technology. According to the Oil Depletion Analysis Centre, 16 new oil fields were discovered in 2000, 8 in 2001, 3 in 2002, andnone in 2003. Nevertheless, a number of positive oil-field discoveries have occurred that indicatenew resources. These include:

• Geological research on the Bakken formation in Montana and North Dakota (2009)• Sixty miles off coast of Florida• Brazil oilfield (2007)• South Australia (2007)• Gulf of Mexico near New Orleans (2006)• Brazil oilfield (2005)

The Hubbert peak theory describes how future world petroleum production will peak and thenstart the process of global decline. This decline will closely match the rate of former increase, asknown oil reservoirs move to exhaustion. This theory also describes a method to calculate thepeak using discovery and production rates, in combination with known oil reserves. The BigRollover is another theory that predicts how global oil production will soon peak, and worldwideproduction will begin to decline.

There are two basic theories about the future of global petroleum resources and supplies. Someexperts argue that we are not running out of oil; rather, we are running into it.The evidence for sup-porting or rejecting this stance can be analyzed by the 5- and 20-year trends of oil explorationproductivity and the U.S. oil recoverable reserves market. Most experts believe it is not a questionof if we will run out, but when. A bright spot in the identification and recovery of reserves is thelarge offshore regions of Texas and Louisiana.

A fundamental question remains: How much oil is there? The estimated ultimately recoverable(EUR) refers to the total amount of crude oil that will ultimately be recovered. This number is difficult to calculate and fluctuates frequently. Oil reserves are typically underestimated and thenumbers are adjusted as additional information and new technology become available. Most

1.2 Current Issues and Trends

16


experts believe that the world’s total endowment of oil comes to about 1.2 trillion barrels.The worldcurrently consumes 30.7 billion barrels per year. By the end of 2008, the world had consumedmore than 1.12 trillion barrels. Figure 1–8 shows the history of crude oil consumption.

To extend our natural resources, modern manufacturers will need to look at alternative fuelsources and technologies. Some of these alternative sources include converting natural gas intooil, recovering oil from tar sands, recovering oil from shale, using Antrim shale to produce naturalgas, and using coal to produce syn-gas. New technologies with tension-leg platforms for deep-water exploration may open up new oil fields. It is entirely possible that the future may find a wayto recycle, recover, combine, and shift our dependence to new technologies and resources. Thefollowing chart shows estimated 2008 world reserves.

Reserves Production Reserve Life Country (109bbl) (106bbl/d) (years)

USA 21 4.9 12

Canada 179 2.7 182

Mexico 12 3.2 10

Saudi Arabia 260 8.8 81

Kuwait 99 2.5 108

Iraq 115 3.7 101

United Arab Emirates 97 2.5 107

Russia 60 9.5 17

World s Total Endowment of Crude Oil

Oil production inbillions of barrels

Global consumption 30.7 billion barrels per year

0

500

1000

1500

2000

2500

3000

3500

0

5

10

15

20

25

30

35

1850 1950 2050 2150

Empty

Crude OilProduction

Figure 1–8 The History of Crude Oil Consumption

17

Reserves Production Reserve Life Country (109bbl) (106bbl/d) (years)

Iran 105 2.2 143

Venezuela 80 2.4 91

Libya 41.5 1.8 63

Nigeria 36.2 2.3 43

China ? ? ?

Many countries have decided that disclosure of their actual reserves is a matter of national secu-rity and refuse to provide accurate data—or any information at all. It is also difficult to estimate howmuch oil can be removed from a reservoir, especially ones in undeveloped countries. It is clearfrom the preceding chart many countries are not represented, meaning that their reserves havenot been calculated.

1.3 Working in the Chemical Processing Industry

Preparation and Basic SkillsPreparation for work in the chemical processing industry starts early for a process technician.Students should take classes in high school that will prepare them for the fast-paced processesand technologies they will encounter in industry. A solid core curriculum would include microcom-puters, communications, math, and science. Some high schools have programs that offer dualcredit for process technology classes. These classes give graduating seniors an advantage overother students entering two-year community college programs.

Jobs in the chemical processing industry are usually high paying and offer full benefit packages.Because of advances in process control, though, fewer positions are available for job seekers.These rapid changes in technology have been integrated into the competitive global structure ofthe chemical processing industry. Job descriptions for process technicians require a two-yeardegree in process technology, good scores on preemployment tests and interviews, and passageof a medical examination.

Reading. To do well on most plant entry exams, above-average reading skills are needed. Opera-tors must read and interpret operating procedures, training procedures, quality and environmen-tal guidelines, customer requests, and many other technical documents.

Writing. Process technicians are required to document most of their activities on the job. Thesedocuments include logbook entries, lock-out, tag-out, process samples, training procedures,operational procedures, permits, shift relief, work orders, and quality control charts. Techniciansmust also be able to communicate clearly and accurately in writing with other industry members.

Listening. Effective listening skills are helpful to process technicians during equipment malfunc-tions, troubleshooting, shift relief, training, and team meetings.

Interpersonal Skills and Communication. Interpersonal skills can be enhanced with propercoaching and study inside a normal process technology program. Most people develop basic skillsyears before entering their occupation, but may find that they need to improve for their jobs.


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Computer Technology. Process technicians interface with their equipment through advancedinstrumentation and electronic networks.The computer console, which is a window to the process,is becoming the central focus of the control room. Technicians need to know how to use personalcomputers. Skills required in this area include using word processors, spreadsheets, databases,and graphics programs; networking with other sites; using electronic mail; accessing operatingprocedures; accessing material safety data sheets (MSDS); understanding computer architecture;and applying new technology as it is developed.

Math. To pass a typical preemployment exam, a process technician needs a sound understanding ofaddition, subtraction, division, multiplication, fractions, percentages, decimals, and measurementmetrics. The technician of the future will need a much stronger understanding of applied mathemat-ics, including: basic math, algebra, geometry, applied college algebra, trigonometry, physics, and cal-culus.These foundational courses can enhance a technician’s ability to perform chemical calculations,to control and troubleshoot unit operations, and to interface with unit chemists and engineers.

Science. Process technologies are based on the principles of general science, chemistry, andphysics. Advanced technology combines raw materials to create useful end products.The sciencebehind this technology is impressive but is usually transparent to the technician. The depth of thetechnology provides a lifelong learning opportunity for the operator. Industrial manufacturersusually upgrade technology frequently in order to compete in the global economy. Most techni-cians are exposed to cutting-edge technology throughout their careers.

It is important to understand what is happening as raw materials are combined to form newproducts. Operators do not open and close valves blindly. They carefully study and prepare priorto operating the unit.

Successful plant operation requires theoretical knowledge and observational knowledge.Typically,the engineering staff is trained in theory, whereas operators control the observational area. Anoperator who possesses both theoretical and observational skills will be a valuable asset to thecompany. Corporate rightsizing and restructuring should require technicians of the future toperform more challenging and technical job functions.

Key scientific principles used by technicians include:

• Fundamentals of chemistry—atoms, elements, atomic structure, hydrocarbons, statesof matter, gases, solutions

• Physics—fluids, temperature, pressure, heat transfer, work, and energy• Math and statistics• Basic equipment and technology• Computer literacy skills• Communication skills• On-the-job skills

Punctuality. Most companies terminate trainees after several unexcused “tardies.” Punctuality isconsidered very important to shift workers. Other key characteristics the chemical processingindustry looks at are fighting, lack of teamwork, drug abuse, safety violations, and excessiveabsences. Studies indicate that job satisfaction is linked directly to low instances of these sorts ofinfractions.

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Multitasking. Process technicians typically have many things going on at the same time. Being ableto control several work tasks at once is important. Process operators commonly carry small note-books around the unit with them to simultaneously document and keep up with a variety of tasks.

Problem Solving. Your ability to solve problems will improve as you become more familiar with theequipment.The trick is to know your equipment and process. It will help you to be familiar with basicproblem-solving techniques so that you can identify the symptom, the problem, and the solution.

Safety Awareness. Safety awareness is taught from the first moment you step into a plant.Statistics indicate that you are safer in the plant than at home, yet every year a large number ofwork-related fatalities and disabling injuries occur in the chemical industry. Evidence indicates thata well-managed safety program drastically reduces occupational illnesses and injuries. Safetystatistics are important to an industrial manufacturer, and extreme pressure is applied to eachemployee to work safely.

Quality Awareness. The new global economy has introduced a competitive way of doing business.Industrial manufacturers use advanced quality techniques to stay ahead of the competition.Thesetechniques are taught openly and used by the entire company. Technicians should be aware ofthese quality techniques, which include flowcharts, control charts, statistical process control,scatter plots, histograms, Pareto charts, run charts, ISO-9000 criteria/certification, and training.

Environmental Awareness. Technicians should be aware of the impact they can have on theenvironment. Industry refers to these programs as air pollution, water pollution, solid waste dis-posal, toxic waste disposal, emergency response, community right-to-know, and spill releaseguidelines (Figure 1–9).


DO I STOPTHE SPILL

ORCALL FIRST?

Phone

Figure 1–9 Spill Releases

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1.4 College Programs for Process Technology

From the early 1960s to the present, community colleges have attempted to work with indus-try to help with operator training. In 1990, a number of colleges began to establish processtechnician training classes. These classes were placed in the continuing education departmentand did not offer regional credit. In these humble beginnings, the original process technologycore curriculum did not exist; however, some similarities did begin to develop among thecourses offered. By 1994, a larger number of schools began the process of curriculum devel-opment for the newly emerging process technology program. A variety of rubrics and coursedescriptions could be found at these different colleges, and variations between colleges weresignificant.

In 1995, the first state-approved certificate was offered in the state of Texas. This was quicklyfollowed by a number of other colleges that launched process technology degrees and one-yearcertificates (see Figure 1–10). In 1997 and 1998, educators worked together to develop a stan-dardized curriculum. In the fall of 2000, educators and industry launched the first standardizedprocess technology program, also in the state of Texas. Other states quickly followed this pattern:Louisiana, New Jersey, California, Alaska, Montana, North Dakota, Alabama, New Mexico, Utah,Wyoming, and Oklahoma. Eight core classes were approved by the states, carried regional credit,and were listed in the college catalogs. Although some variations still exist in these degreeprograms, each includes the eight core classes.

High School to College TransitionThe transition between high school and college can be difficult for many students. Process tech-nology students come from a wide array of backgrounds and experiences. College classes are typ-ically diverse and composed of women and men between the ages of 16 and 60. A significantnumber of these students have college degrees or have completed college classes; however, thelargest block of students have never enrolled in a college course. Making the adjustment betweenhigh school and college is easier if a student is aware of the differences and given the tools to suc-ceed. Figure 1–11 illustrates the differences between college and high school.

High school is vastly different from college. Perhaps the biggest difference between high schooland college is in the area of freedom. Most high school programs are structured with rules thatdictate how personal time is spent. College students are considered to be adults who are allowedto establish their own rules. In high school, the teacher was primarily responsible for selectingand presenting the material. College students are given the opportunity to decide what is impor-tant to them and when they will study it. Because of this freedom, the onus of learning is shiftedfrom the instructor to the student: College instructors place the responsibility for learning on thestudent. Emphasis should be on learning application, not memorization! Technical instructors usea hands-on approach to learning that is similar to the simple practice exams used by high schoolteachers.

Unlike high school, the college student makes a significant financial investment in his or her education. This sacrifice buys a specific product and a huge educational responsibility. College instructors cover a much larger volume of material than high school instructors. Tests are takenfrom class lectures, reading assignments, structured experiments, bench-top labs, pilot units,videos, computer programs, and standardized tests.

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1. STATE-APPROVED CERTIFICATE

2. STATE-APPROVED AAS DEGREE

3. NEW RULES AND REGULATIONS (More Difficult)

— IS THE EMPLOYEE QUALIFIED? — IS THE TRAINER QUALIFIED TO TEACH?

4. PROVIDE INDUSTRY WITH QUALIFIED APPLICANTS

5. UNIONS ARE NO LONGER TRAINING PEOPLE

6. SAVE INDUSTRY TRAINING COST

7. INDEPENDENT CERTIFICATION & RECERTIFICATION

APPRENTICE TRAINING PROGRAMSPROCESS TECHNOLOGY

WHAT NEWRULES AND

REGULATIONS?

CAN I GET A JOBWITHOUT THECERTIFICATE?

WHAT ABOUTJOB PLACEMENT?

HOW MUCH DOES IT COST? HOW LONG DOES

IT TAKE TOFINISH?

8. COLLEGE AND INDUSTRY TRAINING PARTNERSHIP

9. HANDS-ON AND CLASSROOM INSTRUCTION

INDUSTRY AND COMMUNITYCOLLEGES HAVE ENTERED

INTO A TRAININGPARTNERSHIP

Figure 1–10 Process Technology Programs

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Topic College High School

Freedom Controlled by student Controlled by administration

Cost Paid by student Paid by parents (taxes)

Learning Student responsibility Teacher responsibility

Resources Vast and confusing Limited

Job High % work Low % work

Married High % married Low % married

Reward High paying career High school diploma

Good students Sometimes struggle because they do notknow how to apply what they have learned

As and Bs, good GPA

Curriculum Selected by student Selected by administration

Designed by industry, education, andgovernment

Designed by education

Direct job application Not directly applied to careertasks (e.g., history, socialstudies)

Figure 1–11 Differences between College and High School

Figure 1–12 Keys to Success

Tools to Succeed in College

Understanding the college system

Goal setting

Time management

Applied learning

Attitude and participation

Tools for Success in CollegeWhen new process technology students enter college for the first time, they can use a number oftools that have been proven to enhance college performance. Figure 1–12 provides a list of mentaltools used by successful college students.

Understanding the College SystemA new process technology student should be able to quickly decode and understand the educa-tional methodology and administrative requirements that exist in a college. The first step is to get the college catalog and review the rules, procedures, policies, course descriptions, degree

23

programs, and faculty. The second step is to set your college course schedule. Fall, spring, andsummer course schedules will provide you with a detailed listing of classes, locations, instructors,and times.To start school, you will need to complete a third step: register with the college, provideidentification, agree to have your high school send transcripts, and take a series of minor tests forplacement purposes. The process technology degree program will require a student to take be-tween 18 to 22 classes. Full-time students will take 5 or 6 classes over a 16-week period and spendan average of 21 hours per week in the classroom or laboratory.

College instructors usually provide students with a syllabus that contains information on coursedescription, performance objectives, standards, grading policy, attendance policy, textbooks andsupplies, disability assistance, and scheduled exams. Process instructors typically provide students with class outlines. Outlines can be used to prepare for upcoming tests and applied learn-ing activities. The degree program provided by your school will list the required courses to complete the program. Do not get off the path and take classes that will not help you graduate.

College process technology programs award either a one-year certificate or a two-year degree.Certificates require a minimum of 30 semester hours and two-year degrees require a minimum of60 hours. Typical course topics include:

• Introduction to Process Technology• Process Technology 1—Equipment• Process Technology 2—Systems• Process Instrumentation• Safety, Health, and Environment• Process Technology 3—Operations• Quality Control• Troubleshooting• Chemistry and Physics• Math• Academic core classes

During the educational process, a number of snares and traps can damage a student’s ability to progress. Be prepared to drop a class before the scheduled deadline if any of the followingsituations arises:

• You are hopelessly lost and have a D or an F• Instructor-student problems• Work schedule conflict• Family tragedy

Goal SettingGoal setting is a college-level activity used by successful students. Goals should be specific,measurable, and realistic. Short-term goals should be distinguished from long-term goals. Theprocess technology degree program should be broken down into manageable pieces and linkedto weekly, monthly, and yearly goals. Job-search activities are typically more effective when youuse this structured approach.


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Time ManagementTime management combines a student’s knowledge of his or her personal study needs with astructured system. The typical time management system includes:

• To-do list and weekly schedule• Specific study times• Self-discipline• Adequate sleep periods (don’t burn the candle at both ends, and don’t sleep too long.)• Moving to the next action item when time has expired• Mechanism for relaxing

Applied LearningTypical instructional techniques approach learning through a progression from simple to morecomplex. The process technology program presents the theory of process technology in modularblocks before applied techniques are introduced. As the program builds, the learner is exposed tolaboratory equipment and hands-on activities. In the classroom, students may be introduced to thetheoretical concepts of pressure, heat transfer, fluid flow, and distillation; in the laboratory, they areasked to apply these concepts. The ability to transition between the book and the lab is a funda-mental requirement for success in the PT program. Students who perform well in the classroommay struggle on the bench-top, computer simulator, or pilot plant. Other students may perform wellin the lab but do poorly in the classroom.

Attendance and ParticipationStudents who decide early to attend every class and participate in classroom discussion have atremendous edge over those who do not. Instructors learn the names of these students faster andidentify their individual needs more quickly. Participation and attendance are essential elementsin the applied learning process.

1.5 Your Career as a Process Technician

Successful job applicants are notified by telephone or mail/email and given a starting date. Thefirst few weeks include orientation, paperwork, safety training, tours, and apprentice training. Keyindividuals in the organization are given the opportunity to speak to the new process technicians.New employees also spend time getting sized for flame-retardant clothing, safety glasses, andwork boots, as well as being introduced to coworkers.

TrainingIndustrial training programs vary from one company to another. Some are certified by the U.S.Department of Labor.This certification requires a specific number of on-the-job training hours andscheduled classroom hours. These programs can run from one to five years and usually arecorrelated with pay increases.

Key elements of apprentice training programs include:

• Orientation, followed by one to eight weeks of industrial classroom training• Mandatory safety training before being allowed to go to the unit

• Meeting with the supervisor and training coordinator, and planning work and trainingactivities

• Meeting with the trainer and supervisor to plan on-the-job training and a new job assignment

After the introductory period, the process technician is assigned to a unit and a trainer. During thistime, the new technician reports through the formal chain of command, to the trainer and the unitsupervisor. After meeting with the supervisor, the trainer knows the specific area and responsibil-ities of the trainee.Trainees are typically watched very closely during the first year of employment.Training on the unit includes tracing lines, catching samples, filling out paperwork, housekeeping,checking equipment, making line-ups, starting and stopping equipment, and so on. This processcontinues until the trainer feels comfortable with the trainee’s progress. During this time frame, thenew technician works shift work. This can be a very difficult transition for an individual who hasnever worked rotating shifts.

Most companies provide formal apprentice training for new employees regardless of what type ofexperience or training those employees have received previously. Portable credentials (an AASdegree or a certificate) are needed to address the CPI’s apprentice training and experienced-technician retraining problems. These programs provide prospective employers with a list ofqualified candidates who have already completed key elements of the government-required train-ing. Portable credentials could save companies as much as 700 classroom hours.

Diversity, Sexual Harassment, Stress, and ConflictHandling stress, conflict, cultural diversity, and sexual harassment are all important aspects of aprocess technician’s job.The people who make up the workforce within a plant are typically diverseand well educated. Diversity training identifies and reduces hidden biases between people withdifferences. Work relationships can be expected to last as long as 35 to 40 years, so it is impor-tant to fit in on your unit. Understanding your assignments, multiple roles, and responsibilities andcontributing to the overall team effort is important to a successful work career.

Sexual harassment is defined as behavior that constitutes unwelcome sexual advances. Thebehavior could take the form of verbal or physical abuse or unwelcome requests for sexual favors.This behavior may involve persons of the opposite sex or of the same sex, and may involvesupervisor–employee behavior, or employee–employee behavior. In addition to being illegal, sex-ual harassment creates tremendous stress and conflict within the workplace.

New technicians describe entering a chemical processing plant as an unusual experience similarto being transplanted into a foreign environment with pipes, tanks, strange equipment, noises,smells, and advanced computer technology. This initial experience is very stressful for the newtechnician. Each plant has a variety of techniques for reducing the stress on a new technician.Some of these techniques include:

• Systematic, competency-based training• Trainer–trainee on-the-job training• Job shadowing on-the-job training

Stress levels will drop as the new technician qualifies on a job post and becomes more familiarwith the environment.

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1.5 Your Career as a Process Technician

26


Conflicts will naturally occur during the work career of most technicians. How these conflicts arehandled can be used to determine retention rates, evaluations, promotions, absenteeism, and jobsatisfaction. Conflicts must be handled professionally and through the proper channels. New tech-nicians sometimes feel they are being singled out and asked to do the most routine, dirtiest jobs.However, training is typically structured like college work, progressing from the simple to the morecomplex. As you learn and qualify on additional job posts, further responsibilities and the respectof your peers will increase.

It is important to remember that during the first 12 months of employment, the apprentice techni-cian should not:

• Miss work or come in late• Sleep on the job• Use illegal drugs or alcohol• Fight on the job• Be caught in the control room with his or her feet up

During the first year of employment, new technicians are expected to be on their best behavior.You have not yet established a track record, so every activity—positive or negative—counts.

Organizational StructureChemical plants and refineries are divided into major sections or divisions that make the best sensefor the overall operation of the plant. Each section appears to run independently of the others, andeach has a designated section head. Process section heads report directly to the plant manager.Plant managers, section heads, and second-line supervisors typically have engineering degrees.The chemical processing industry follows a pyramid-type management structure that includes theplant manager, section head, second-line supervisors, first-line supervisors, and process techni-cians. A variety of management structures are available; however, large, pyramid-type organizationsrarely diverge from the original design. Work teams vary in size from 5 to 20 technicians.

Inside and Outside OperatorsProcess technicians can be classified as inside or outside operators. Inside operators are typicallyexperienced technicians who are familiar with the outside functions of their unit. As the nameimplies, inside operators spend most of their time inside a control room monitoring and controllingprocess variables, filling out unit logbooks, and working with the outside operator. The majority ofprocess technicians are outside operators who inspect equipment, perform unit start-ups andshutdowns, troubleshoot problems, perform routine housekeeping, catch readings, and collectsamples.

1.6 Careers in the Chemical Processing Industry

Electricians, instrument technicians, lab/research technicians, machinists, mechanical craftsmen,and process technicians work as a team to control the operations of a plant (see Figure 1–13).They work with chemists, engineers, secretarial and clerical staff, attorneys, legal assistants, com-puter specialists, industrial hygienists, and human resource analysts. Each of these occupationsstarts at different pay rates. The primary financial difference among the four craft occupations andprocess is shift differential and overtime. Most operating facilities run between 20% and 25%

27

overtime for process technicians. In the gulf coast area (Texas and Louisiana), in 2005, a typicalstarting rate was $22 to $26 per hour for a 12-hour shift, with a top-out rate of around $34.Depending on the amount of overtime worked, new technicians will earn between $62,920 and$74,360 during their first year (2008–2009 Gulf Coast area). Top-out rates in the chemical pro-cessing industry are presently between $28 and $38 per hour. Time and a half can add up to asmuch as $57 per hour for a senior technician working overtime. A typical year will include 2,080scheduled work hours plus about 25% (520 hours) of overtime.

Process, Research, and Chemical TechniciansProcess Technician. Start: $22 to $34 per hour; $62,920 to $74,360 per year with 25% overtime.Certificate, AAS degree, or three years’ experience. Maintain unit operations: check equipment,catch samples, take readings, make rounds, troubleshoot, fill out quality charts, operate computersystems, and do housekeeping. Must have strong technical and problem-solving skills, ability toassimilate cutting-edge technologies quickly, and ability to apply innovative ideas. In addition tothese skills, a process technician needs to be able to handle conflict, look at a complex situationand see the overall picture, and communicate effectively.

Research Technician. Start: $22 to $34 per hour; $62,920 to $74,360 per year with 25% overtime.Certificate, AAS degree, or three years’ experience. Same as process technician plus: operatebench-top units and pilot plants. Special emphasis on technical and problem-solving skills, abilityto assimilate cutting-edge technologies quickly, and ability to apply innovative ideas.

1.6 Careers in the Chemical Processing Industry

Process TechnicianResearch TechnicianLaboratory Technician

ElectricianInstrument TechnicianMechanical CraftsmanMachinist

Chemical EngineerMechanical EngineerElectrical EngineerChemistPlant Management

Patent AttorneyLegal Assistants

SecretarialClerical

Financial Analyst

Human Resource Analyst

Computer Science Analyst

Figure 1–13 Careers in Industry

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Lab Technician. Start: $22 to $34 per hour; $62,920 to $74,360 per year with 25% overtime. (Note:Overtime is typically lower than 25% for this occupation.) Certificate, AAS degree, or three years’experience. Degree must include two to three classes in chemistry, math, and physics. Performquality control tests.

Mechanical CraftsElectrician. Start: $19 to $31 per hour; $39,520 per year to start. AC/DC voltage hook-ups, circuittesting, troubleshooting, electrical controls.

Instrument Technician. Start: $19 to $31 per hour; $39,520 per year. Work on level, fluid flow,pressure, and temperature instruments and control loops; troubleshoot; maintain operations.

Machinist. Start: $21 to $34 per hour; $43,680 per year. Maintain mechanical equipment, checkrotating equipment alignments.

Mechanical Craftsman. Start: $19 to $32 per hour; $39,520 per year. Includes pipe fitting andwelding, equipment maintenance, troubleshooting.

Engineering and ChemistsContact Engineer. Start: $34 per hour; $70,720 per year. Bachelor of Science in ChemicalEngineering (BSCE) degree. Assigned to operations unit for technical support.

Design Engineer. Start: $32.55 per hour; $67,704 per year. Bachelor of Science in MechanicalEngineering (BSME) degree. Troubleshoot equipment and machinery problems.

Chemist. Start: $43.65 per hour; $90,792 per year. PhD in chemistry. High grade-point averageand experience.

Administrative Support StaffSecretarial, Clerical, and Legal Assistant. Start: $18.12 per hour; $37,689 per year. Wordprocessing, computer literacy, and communication skills. Type reports, memos, and letters; dolegal research and analysis; perform special services for attorneys.

ComputersComputer Science Analyst. Start: $29.30 per hour; $60,944 per year. Bachelor of Science inComputer Science. Maintain plant computer systems.

PersonnelHuman Resources Analyst. Start: $35.73 per hour; $74,318 per year. Master’s degree in IndustrialRelations. Recruiting, labor relations, training, equal employment opportunity (EEO) compliance.

SafetyIndustrial Hygienist. Start: $30.58 per hour; $63,606 per year. Bachelor’s degree in Environ-mental Engineering. Ensure compliance with OSHA; help employees to recognize, control, and evaluate occupational hazards.

OtherFinancial Analyst. Start: $35.73 per hour; $74,318 per year. Master’s Degree in Business Administration (MBA). Develop budgets, analyze costs, monitor expenses.

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Patent Attorney. Start: $31.44 per hour; $65,395 per year. Bachelor of Science degree, law degree (Juris Doctor). Protect company inventions, patents, contracts, license agreements.

1.7 Roles and Responsibilities of a Process Technician

At present, the chemical processing industry is predicting a severe shortage of skilled techniciansto operate their plants. Figure 1–14 shows the “Baby Boom” group in the chemical processingindustry that will soon reach retirement age. Over the next 7 to 12 years, the CPI will be forced toreplace 70% to 80% of the existing workforce. Future hiring trends indicate that educationallevels will continue to drop across the United States. At the same time, advanced technology hascaptured the CPI and been distributed to the existing workforce. Much of this cutting-edge tech-nology is so expensive and new that local colleges and universities have not had time to integrateit into their curricula. Records indicate that 70% of high school students in the United States donot have the basic skills required to work in the chemical processing industry.

Educators and local industry have formed alliances to help develop a standardized curriculum forthe technician of the future. The term gold collar is being used to describe the occupation of aprocess technician. Currently, two models are emerging as the dominant theories concerning whatprocess technicians will be doing in the next century. The American Chemical Society (ACS)believes that the roles of process technicians, engineers, and chemists will overlap more in thefuture, with technicians taking on job responsibilities and tasks typically performed by engineersand chemists. The second model forecasts that process technicians will take on more of the re-sponsibilities now typically reserved for instrumentation, electrical, and maintenance workers.Thissecond model is popular in nonunion areas; however, union plants are not likely to adopt it.


325,000

65%

JOBS

35%

2009

Born: 1943-1960

175,000500,000

JOBS

Ages19-61

Ages49-61

Ages19-48

JOBS

BABY BOOMERS

Born: 1961-1981Born: 1982-2001

Generation(s) X & Y

100%

This group willretire over the next

12 years

Figure 1–14 Typical Age Distribution

30


Figure 1–15 shows the most popular model supported by the ACS, the predicted model ofshared responsibilities.

Process Technicians in the 21st CenturyThe standard roles and responsibilities of process technicians include understanding and masteryof basic equipment, design, operation, and maintenance. New process technicians will learn aboutvalves, pumps, compressors, steam turbines, instrumentation, heat exchangers, cooling towers,boilers, furnaces, reactors, and distillation columns. In addition to this, technicians will learn howthe equipment operates and specific maintenance procedures. Key scientific principles such asheat transfer, compressibility, pressure, and fluid flow will be discussed in relation to the equip-ment. The technicians of the future must have strong technical and problem-solving skills, theability to assimilate cutting-edge technologies quickly, and the ability to apply innovative ideas. Inaddition to these skills, a process technician needs to be able to handle conflict, look at a complexsituation and see the overall picture, communicate effectively, and use and understand modernprocess control.

Operators are also responsible for relieving other technicians working a job post, performing shifttasks, making rounds, catching samples, taking readings, troubleshooting unit problems, andfilling out control documentation. Process technicians are responsible for maintaining and moni-toring equipment, inspecting equipment, placing equipment in service, removing equipment fromservice, and responding to emergency situations. Additional responsibilities include unit and com-munity safety, maintenance of regulatory and environmental standards, accident prevention, fireprevention, production, housekeeping, and product quality.

The American Chemical SocietyIn 1994, the American Chemical Society sponsored a project called “Foundations for Excellencein the Chemical Process Industries.”The goal of the project was to develop voluntary industry stan-dards for chemical process industry technical workers (laboratory and process technicians). TheACS has been supported in this research by a wide array of community, industrial, and educationalinstitutions. The standards developed under this project were designed to assist educators in curriculum development, instructional strategies, and chemical and process technology programdesign.

ProcessTechnicians

Engineering Chemists

Overlap indicates shared responsibilities

MODEL ONE

ProcessTechnicians

Engineer-ing

Chemists

20052015

Figure 1–15 Predicted Model

31

The standards developed by the ACS identify the knowledge and skills that process techniciansneed when they begin work in a manufacturing environment.This identification of standards is partof a much larger grassroots movement toward the development of two structured professions: lab-oratory and process technician. These two professions have developed in response to the tech-nology revolution.

Training ProgramsIn the past, very little formal training was required prior to taking a job in the chemical processingindustry (CPI). Industrial manufacturers relied on preemployment screening and in-house trainingprograms to educate and recertify their employees. Nationally, this method for training is chang-ing. Because of intense competition in the global community, the CPI is evaluating whether acompany’s focus should be on training or producing products. When a company identifies a partof its day-to-day operation that could better be operated by an outside organization and hires oruses this organization, this is called outsourcing. Outsourcing of training is becoming a very pop-ular option for industrial manufacturers.

Formal industry training programs have been established in local community colleges and uni-versities nationwide. At present, these college programs in process technology are limited tothree or four geographic regions across the United States. Students can attend these institutionsand receive state-approved certification and two-year degrees in laboratory or process technol-ogy. These programs relieve the employer’s burden of typical apprentice training and allow indus-trial trainers to focus on higher-level, site-specific training. Graduates from these types of programsprovide a much larger pool of qualified applicants from which the CPI can choose. In time,preemployment tests will evolve from the typical math and mechanical aptitude tests into a morecomprehensive exam covering the entry-level skills discussed in this text. Another popular optionbeing discussed is to waive the preemployment test and use the candidate’s college transcripts.This method appears to work well for other occupations, such as engineering, law, medicine, andchemistry.

New Hiring StandardsEmployers are requiring prospective employees to have one or more of the following: (1) formaltraining, (2) state-approved certification, (3) a technical degree, (4) experience, (5) satisfactoryscores on a preemployment test, or (6) a combination of these attributes. The chemical process-ing industry and various educational institutions have entered into formal partnerships to facilitatethe technical training of employees.

Program JustificationThe key reasons driving the development of these technical programs are: (1) rapid advances intechnology, (2) desire to eliminate accidents in the workplace, (3) potential catastrophic risks, and(4) new regulations and guidelines from the government. The Occupational Safety and HealthAdministration (OSHA) recently enacted a process safety management (PSM) standard that re-quires employers to train their employees on process fundamentals. This standard applies to initialcertification and recertification of employees. (See Chapter 2 for more details on the PSM standard.)

Workforce DevelopmentAccording to the ACS, more than 240,000 chemical laboratory technicians and 500,000 planttechnical operators are employed in the United States.This group makes up the fourth largest U.S.manufacturing industry. Studies of workforce development indicate that much of the existing


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Employability Performance-Based Skills

Math and Statistics (22 Lab Objectives) (13 Process Objectives)

Computer literacy (19L) (12P)

Communication (31L) (14P)

Workplace (25L) (19P)

General plant and lab (32L) (16P)

workforce is comprised of the “Baby Boom” generation and is mature. In the near future, this largegroup will “boom out” or retire, leaving a significant number of vacancies. Measures must be takensoon to stop the loss of technical expertise from this generation, to capture it in the form of techni-cal programs, and to assimilate it into the modern U.S. workforce. Figure 1–16 shows the develop-ment of the chemical processing industry, as illustrated by this large chemical processing plant.

The ACS has taken significant steps toward the development of a practical, technical foundation.The ACS standards need to be used in the development of future technology programs. Many ofthe objectives listed in the ACS’s major categories are found in the body of this text. A report on theproject, Foundations for Excellence in the Chemical Process Industries, can be obtained by writingto the American Chemical Society, 1155 Sixteenth Street NW, Washington, DC 20036; (202) 872-8734. The standards identified by the group for laboratory and process technicians follow.

Figure 1–16 Chemical Processing Industry

33

Critical Job Functions: Laboratory

• Maintain a safe and clean laboratory adhering to environmental/health and safetyregulations (34L).

• Sample and handle chemical materials (31L).• Conduct physical tests (20L).• Perform chemical analysis (37L).• Perform instrumental analysis (38L).• Plan and design experiments; synthesize compounds (53L).

Critical Job Functions: Process

• Maintain safety, health, and environmental standards in the plant (30P).• Handle, store, and transport chemical materials (33P).• Operate, monitor, and control continuous processes (27P).• Operate, monitor, and control batch processes (33P).• Provide routine and preventative maintenance and service to processes, equipment,

and instrumentation (32P).• Analyze plant materials (36P).

Basic process equipment and technology standards are covered at the beginning of each chap-ter in this book. The subject matter covered in this text is designed to closely resemble currentinformation found in a typical apprentice training program.

Industrial manufacturers spend millions of dollars on equipment and technology to produce theirproducts. These same manufacturers employ process technicians to operate and maintain theirplants. Taking care of the equipment and operation is the primary responsibility of a process tech-nician. Process technicians maintain and operate the equipment 24 hours a day, 7 days a week.Because of this unique relationship, process technicians become the hub of everyday operations.

Operators are responsible for:

• Knowing the basic equipment, design, and operation• Equipment operation and specific maintenance procedures

– Making relief– Performing shift tasks– Making rounds– Troubleshooting unit problems– Filling out control documentation– Maintaining and monitoring equipment– Inspecting equipment– Placing equipment in service– Removing equipment from service– Responding to emergency situations

• Safety, health, and environment• The principles of quality• Strong technical and problem-solving skills, with the ability to adopt and assimilate

cutting-edge technologies quickly and apply innovative ideas


• Ability to handle conflict, look at a complex situation and see the overall picture,communicate effectively, and use and understand modern process control

• Ability to understand basic chemistry, physics, and math

Modern manufacturing plants are comprised of complex networks that work closely with eachother. The people who operate and maintain these networks include:

• Process, research, and laboratory technicians• Maintenance technicians: instrument technicians, electricians, mechanics, and

machinists• Engineers and chemists• Administrative, human resources, legal, and financial analysts• Computer analysts• Safety and industrial hygienists• Janitorial technicians• Construction: brick, carpentry, structural steel, concrete, and rigging workers

1.8 Regulatory Agencies

A number of regulatory agencies work closely with and periodically monitor specific activities in thechemical processing industry. At the federal level, some of these agencies include theEnvironmental Protection Agency (EPA), the Occupational Safety and Health Administration(OSHA), the Department of Transportation (DOT), and the Nuclear Regulatory Commission (NRC).

Nuclear Regulatory CommissionThe U.S. Nuclear Regulatory Commission was established by the Energy Reorganization Act of 1974 to regulate nonmilitary use of nuclear materials. The NRC is an independent agency that:

• Ensures public safety• Protects the environment• Promotes national security and defense• Regulates civilian use of nuclear materials

Process technicians working at nuclear power generation plants will follow guidelines establishedby the NRC in reactor operation, use of nuclear materials, and waste disposal.

The NRC regulates the industry through a four-step approach: (1) regulations and guidance, (2) licensing and certification, (3) oversight, and (4) operational experience. Each of these fourareas is supported by research activities, advisory activities, and adjudication. Figure 1–17illustrates how this process works.

Under the first step, regulations and guidance, the NRC develops and amends regulations for licensure or certification, develops and revises guides, reviews plans, and updates the NRCinspection manual. The NRC sends updates and information to new applicants and licensees.

34


35

1.8 Regulatory Agencies

1. Regulations and Guidance

• Standards Development• Rules• Guidance• Communications

3. Oversight

• Inspections• Investigations• Assessment• Enforcement• Allegations

4. Operational Experience

• Assessment• Generic Issues

2. Licensing and Certification

• Certification• Licensing

Figure 1–17 How the NRC Regulates Industry

Standards development is a cooperative agreement between the NRC and industry for areasconcerning equipment, systems, and raw materials.

Nuclear reactors use and produce materials that are carefully regulated. Special nuclearmaterials include uranium-233, uranium-235, enriched uranium, and plutonium. Source mate-rials include natural uranium, thorium, and depleted uranium that cannot be used as reactorfuel. By-product material is generated from nuclear materials; these by-products include anyradioactive material or waste products produced by the reactor system. In 2004, there wereapproximately 104 nuclear facilities in the United States; the majority of these systems arelocated in states east of the Mississippi River. Only 19 nuclear reactors are operated west ofthe Mississippi.

Department of TransportationRaw materials that enter the plant from public roads and highways, railroads, maritime channels,or air are regulated by the U.S. Department of Transportation. Process technicians responsible forshipping out raw materials and products will receive specialized training that will clearly identifyand explain specific rules, regulations, and procedures. The DOT system includes the use oflabels, signs, and placards. Chapter 3 contains additional information on the DOT.

The DOT umbrella covers a wide array of organizations, including:

• Office of the Secretary—the Secretary of Transportation is the principal advisor and isassisted by the deputy secretary in overseeing formulation of the national transportationpolicy

• Bureau of Transportation Statistics• Federal Aviation Administration• Federal Highway Administration• Federal Motor Carrier Safety Administration• Federal Railroad Administration• Federal Transit Administration• Maritime Administration• National Highway Traffic Safety Administration• Research and Special Programs Administration• Saint Lawrence Seaway Development Corporation• Surface Transportation Board

Environmental Protection AgencyThe Environmental Protection Agency employs more than 18,000 people across the UnitedStates. More than 50% of these individuals are engineers, chemists, or scientists. The Presidentof the United States appoints the administrator of the EPA and carefully monitors all majoractivities. Established in 1970 to protect human health and the American environment, the EPAworks for cleaner water, air, and land. This is accomplished as the EPA heads up the country’senvironmental research, science, assessment, and educational process.

Understanding the role of the EPA is important for a process technician. The EPA is charged withenforcing the laws enacted by Congress, and does so by designing, developing, and enforcing regulations. Its mission statement applies to a variety of environmental programs.

36


37

1.9 The Work Environment

Occupational Safety and Health AdministrationAnother regulatory agency that works closely with the chemical processing industry is the Occu-pational Safety and Health Administration .Three groups were created by the Occupational Safetyand Health Act of 1970: OSHA, the Occupational Safety and Health Review Commission(OSHRC), and the National Institute for Occupational Safety and Health (NIOSH).

1.9 The Work Environment

It is important to discuss the work environment that a process technician will be asked to performin. Each chemical plant or refinery is a city within a city that has its own political structure and livingenvironment. This includes the equipment, systems, processes, and people that are unique to theindustry.

The chemical processing industry operates with a variety of work shifts that include 8- and12-hourrotating shifts. Some smaller facilities shut down over the weekend or even at night; however, themost common work schedule is 24 hours a day, 7 days a week. Process technicians work in an all-weather work environment; that is, they must complete work assignments during a variety ofweather conditions.

Operational work crews are required to work in a drug- and alcohol-free work environment. Thechemical processing industry is an environment that is constantly changing. Team structures arefrequently directed internally on the off shift. Shift work has a variety of side effects that should beconsidered prior to committing to the educational requirements and preparation needed to qualifyfor a position. Rotating shifts confuse a number of biological functions. Sleep patterns may becomeerratic and mental fatigue may create problems with job effectiveness. Eating habits are alsoaffected by rotating shift work. This may result in rapid weight loss or increase, or a combinationof both that stimulates wide weight swings. This can put serious stress on the primary organs,including the heart.

A large problem each new technician faces is integrating into the work team. New teams go througha series of stages, including forming, storming, norming, and performing. However, process teamsare typically well developed and mature, and these stages are long settled. Team dynamics areaffected by a complex assortment of human attributes. The corporate culture inside the chemicalindustry generates specific triggers that are designed to create synergy to accomplish organizedgoals. When the key individuals of a team combine to accomplish organizational goals, synergy isformed.When the organization fails to convince each member of the team to work toward companygoals, a series of factors associated with team failures is initiated and synergy declines.

Refineries and chemical plants make a significant impact on the community and other industries.Large plants provide jobs and are a major source of manufacturing.These organizations purchaseraw materials, both locally and internationally. Local resources include food, water, electricity, com-pressed gases, education, and so on.The CPI provides serious tax revenues for local schools andcolleges. Chemical plants and refineries are typically built in close proximity to each other so thatraw materials and products can be exchanged. Community features that will attract global indus-tries include an educated workforce, inexpensive raw materials, central location, and high-qualitylocal shipping lanes, railroads, pipelines, and roads.

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Summary

The lifeblood of modern society is found in petroleum products. Cars, planes, trains, ships, andfarm equipment all require petroleum products to operate. Crude oil is a mixture of hydrocarbonsthat vary in molecular structure and weight. Modern manufacturers separate these componentsthrough the distillation process.

In 1859, Edwin L. Drake began drilling for oil near Titusville, Pennsylvania. Almost immediately,Drake’s well produced oil, and this success encouraged other oil drillers to set down wells. In 1860,the first refinery was built by William Abbott and William Barnsdall at Oil Creek. Their batch oper-ation produced gasoline, naphtha, kerosene, and bottom residuum.

Early refiners were able to produce only 11 barrels of gas from every 100 barrels of crude oil.Because of this low yield, the industry began to look for ways to increase gasoline production with-out increasing the reserves of less profitable products. Modern refiners are able to convert 45% ofa barrel of crude oil into gasoline, using thermal and catalytic methods. Combining processesinclude alkylation, polymerization, and reforming.

The first fractionating column was introduced in 1917. In the “still upon a still” design, as the heatedcrude oil flowed into the column, a fraction of the feedstock vaporized and rose up through theupper stills. The heavier components flowed through the lower stills to the bottom of the column.

A number of trends are anticipated in oil production in the next 20 years, including the Big Rollover(when oil production peaks, and begins to decline). Many oil experts believe this will occur withinthe next 10 to 15 years. Most experts agree that the earth’s estimated ultimately recoverable oilreserves are about 1.2 trillion (short-scale) barrels without oil sands and 3.74 trillion barrels withoil sands. Present global consumption is 84.6 million barrels a day or 30.7 billion barrels per year.The United States produces 4.9 billion barrels per year and refines more than 8.5 billion barrelsper year, while importing more than 16 billion barrels per year for commercial needs. Thesereserves cannot be replaced once they are used, and some projections indicate that, at our pres-ent rate of consumption, our oil reserves will be depleted during the next 38.8 years to 122.2 years.At the end of 2008, the world had consumed 1.12 trillion barrels.

Each year, production from the world’s existing oil reserves drops by approximately 7%. Theselosses must constantly be made up through new reserve finds and new technology.

The standard roles and responsibilities of process technicians include understanding and masteryof basic equipment, design, operation, and maintenance. Process technicians are also responsiblefor relieving other technicians and working a job post, performing shift tasks, making rounds,catching samples, taking readings, troubleshooting unit problems, filling out control documentation,maintaining and monitoring equipment, inspecting equipment, placing equipment in service,removing equipment from service, and responding to emergency situations.

The chemical processing industry and various educational institutions have entered into formalpartnerships to facilitate the technical training of employees. The key reasons driving theseprograms are rapid technological advances, the desire to eliminate workplace accidents, potentialcatastrophic risks, and government guidelines, including the recently enacted process safetymanagement standard.

Preparation for work in the chemical processing industry starts in high school with interpersonalskills, microcomputers, communications, math, and science. College students are given anopportunity to complete courses developed by education and industry, structured according to aset of nationally accepted objectives, and taught by people with years of industrial experience.

College PT classes focus on the equipment found in the chemical processing industry. The initialcourse goes into some depth about the various areas. The second course presents varioussystems in which equipment is commonly used. The last core course allows a process technicianto operate one or more of the systems found in the chemical processing industry.

A number of regulatory agencies work closely with and periodically monitor specific activities inthe chemical industry.These agencies include the Environmental Protection Agency, the Occupa-tional Safety and Health Administration, the Department of Transportation, and the NuclearRegulatory Commission.

A process technician must be able to integrate well with existing employees and learn to handleworkplace stresses and challenges successfully. The chemical processing industry operates witha variety of work shifts, including that include 8- and12-hour rotating shifts. Rotating shift work hasbiological side effects that must be considered and dealt with. The work environment in thisindustry is constantly changing.

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Summary

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Chapter 1 Review Questions1. Describe process technology training programs.

2. What skills do technicians need for success?

3. Describe a typical apprentice training program.

4. List three differences between high school and college.

5. What is your motivation for pursuing a career in process technology?

6. What is time management?

7. What is diversity?

8. Define sexual harassment.

9. List five significant events in the history and development of the chemical processingindustry.

10. Describe the primary issue in oil production today.

11. What tools must a student acquire and use to be successful in a process technology program?

12. What is process technology?

13. List all process technology classes offered at your school.

14. Calculate the gross income of a first-year technician.

15. Calculate the gross income of a senior technician at top rate. Use the standard of 2,080hours plus 1,000 overtime hours at time and a half.

16. Describe batch operation.

17. Contrast thermal and catalytic cracking.

18. Identify two inventions that revolutionized the chemical processing industry.

19. Who was called the “father of the gas industry”?

20. What event took place in 1859 that changed the chemical processing industry?

21. Describe fractional distillation.

22. What are the primary responsibilities of a process operator?

23. Identify the future trends that have been predicted for the process industry.

24. Explain the function of regulatory agencies by describing one such agency and itsresponsibilities.

25. Describe how shift work can affect the process technician.

26. What are the five basic skills of equipment training?

27. Describe the “Big Rollover” and the Hubbert peak theory.

28. Describe the biogenic theory.

29. Describe the typical molecular composition of crude oil.

30. List some specific products manufactured from petroleum.

Introduction to ProcessTechnologyAfter studying this chapter, the student will be able to:

• Describe the process technology curriculum and Associate of Applied Sciencedegree plan.

• List the key principles of safety, health, and environment.• Describe the influence of the PSM standard on the process technology

curriculum.• Describe the content of a course on the basic principles of quality control.• Describe the content of a course on principles of instrumentation and modern

process control.• Describe the content of initial and advanced process equipment courses,

including systems and process operations.• Describe the various systems found in the chemical processing industry.• Describe a college-level troubleshooting course, including models and methods

that may be taught as part of this course.• Describe how science courses prepare the student to apply the principles of

chemistry and physics in the chemical processing industry.• Explain how the process technology curriculum is used to prepare a student

for employment in the CPI.

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Key TermsApplied General Chemistry—study of the general concepts of chemistry with an emphasis onindustrial applications. Students measure physical properties of matter, perform chemicalcalculations, describe atomic and molecular structures, distinguish periodic relationships ofelements, name and write inorganic formulas, write equations for chemical reactions, demon-strate stoichiometric relationships, and demonstrate basic laboratory skills.

Applied Math for Process Technicians—variations in this area include studies in two or moreof the following areas; basic mathematics, technical algebra, math with applications, collegealgebra, statistics, trigonometry, statistics, applied or academic physics.

Faculty expectations—college faculty’s assumption that process technology students will beresponsible for their own learning, setting goals, managing their time, participating in classactivities, and attending scheduled class meetings.

Introduction to Process Technology—a survey course of all the courses found in the region-ally accredited process technology program.

Occupational Safety and Health Administration (OSHA)—Federal agency created by theOccupational Safety and Health Act; composed of three division: the Occupational Safety andHealth Administration, the National Institute for Occupational Safety and Health, and theOccupational Safety and Health Review Commission.

Principles of Quality—course covering the background and application of quality concepts.Topics include team skills, quality tools, statistics, economics, and continuous improvement.Focuses on the application of statistics, statistical process control, math, and quality tools toprocess systems and operations.

Process—a collection of equipment systems that work together to produce products (e.g.,crude distillation).

Process Instrumentation—course for study of the instruments and instrument systems usedin the chemical processing industry; includes terminology, primary variables, symbology, con-trol loops, and basic troubleshooting. The purpose of this class is to provide students with anunderstanding of the basic instrumentation and modern process control used in the chemicalprocessing industry.

Process technicians—Process technicians have advanced training in the equipment, technol-ogy, and scientific principles associated with modern manufacturing. Process technicians typ-ically have college degrees and can be found operating and troubleshooting the complexsystems found in the chemical processing industry.

Process Technology—as defined in the regionally accredited process curriculum, course forstudy and application of the scientific principles (math, physics, chemistry) associated withthe operation (instruments, equipment, systems, troubleshooting) and maintenance (safety,quality) of the chemical processing industry.

Process Technology 1—Equipment—instruction in the use of common process equipment,including basic components and related scientific principles. Includes a study of valves, pipesand tanks, pumps, compressors, motors and turbines, heat exchangers, cooling towers, boilers,furnaces, distillation columns, reactors, and separators.

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Chapter 2 ● Introduction to Process Technology

Process Technology 2—Systems—study of common process systems found in the chemicalprocess industry, including related scientific principles. Includes study of pump and compressorsystems, heat exchangers and cooling tower systems, boilers and furnace systems, distillationsystems, reaction systems, utility system, separation systems, plastics systems, instrument sys-tems, water treatment, and extraction systems. Computer console operation is often included insystems training. Emphasizes scale-up from laboratory (glassware) bench to pilot unit. Describeunit operation concepts; solve elementary chemical mass/energy balance problems; interpretanalytical data; and apply distillation, reaction, and fluid flow principles.

Process Technology 3—Operations—combines process systems into operational processeswith emphasis on operations under various conditions. Topics include typical duties of anoperator. Instruction focuses on the principles of modern manufacturing technology and processequipment. Emphasizes scale-up from laboratory bench to pilot unit. Describe unit operationconcepts; solve elementary chemical mass/energy balance problems; interpret analytical data;and apply distillation and fluid flow principles. The purpose of this class is to provide adultlearners with the opportunity to work in a self-directed work team, operate a complex opera-tional system, collect and analyze data, start and stop process equipment, follow and write op-erational procedures. The course is advanced and requires the learner to apply classroom skillsto real-life operational activities. Students are required to qualify and operate a process unit.

Process Troubleshooting—instruction in the different types of troubleshooting techniques,methods, and models used to solve process problems. Topics include application of datacollection and analysis, cause-effect relationships, and reasoning. Emphasizes application oftroubleshooting methods to scale-up from laboratory bench to pilot unit. Describe unit opera-tion concepts; solve elementary chemical mass/energy balance problems; interpret analyticaldata; and apply distillation and fluid flow principles.

PSM standard—a governmental process safety management standard designed to prevent thecatastrophic release of toxic, hazardous, or flammable materials that could lead to a fire,explosion, or asphyxiation.

Safety, Health, and Environment—course in which students gain knowledge and skills toreinforce the attitudes and behaviors required for safe and environmentally sound work habits.Emphasizes safety, health, and environmental issues in the performance of all job tasks, andcovers regulatory compliance issues.

System—a collection of equipment designed to perform a specific function (e.g., refrigerationsystem).

2.1 Introduction to Process Technology

Process technology, as defined in the regionally accredited process curriculum, is the study andapplication of the scientific principles (math, physics, chemistry) associated with the operation(instruments, equipment, systems, troubleshooting) and maintenance (safety, quality) of thechemical processing industry. The term process technology was first created in the community-college environment to describe a new program being designed to train process technicians. Twoprogram descriptions were developed at the same time: process technology and chemicaltechnology. Originally the rubrics were PTEC and CTEC. Chemical technology is used to trainlaboratory technicians. Figure 2–1 shows campus facilities used to prepare adult learners foremployment in the chemical processing industry (process or laboratory). This could includeresearch pharmaceutical, food processing, power generation, operator, or process technicians.


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44


Figure 2–1 The Community College

A process technology student is required to study the equipment and technology common to mostindustrial processes and to understand the relationships they share. For example, piping, valves,pumps, and tanks share a unique relationship common to many processes.

In a process technology program or course of study for the Associate of Applied Science degree,a student will learn the principles of modern process control and troubleshooting. Most programsstart this process using the five elements of a control loop as a guide. Because new governmentalguidelines require process technicians to understand the chemistry of the processes they are op-erating, a solid foundation in applied math, physics, and chemistry is required. Calculating producttransfers; mixing raw materials to form new products; and dealing with pressure, level, flow, andtemperature problems are all areas to which the math/science foundation is commonly applied.

During the program, a student will be exposed to advanced quality control techniques, safety train-ing from a process technician’s view, and human relations. The knowledge and skills learned inthe process technology degree program can be directly applied to a number of hands-on learningactivities at the educational institution before being applied on the job.

When students enroll in a process technology program, faculty expectations are that the studentswill have the skills to complete a regimented curriculum (Figure 2–2) that has been developed byeducation, industry, and governmental agencies. Successful completion of a regionally accreditedprogram requires a student to demonstrate the following skills:

• Self-directed study habits—attendance, participation, critical thinking, troubleshoot-ing, goal setting, time management, motivation, reading and study, homework, self-directed work ethic

• Interpersonal skills—listening, communication, diversity awareness, using qualitytools, honesty, integrity, working with supervision

• Safety awareness—safety, health, and environmental considerations• Application of the principles of quality control to process operations• Use of complex instrumentation systems• Basic understanding of the equipment and technology—computer literacy, basic math

and science, mechanical aptitude, assimilation of skills, hands-on operation• Recognition and operation of various process systems• Troubleshooting of typical process problems


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Figure 2–2 College Classroom

Introduction to Process Technology is the first course taken in the process technology program.It is specifically designed to provide the adult learner with a general overview of the entire program.Process technology programs include eight core classes:

• Introduction to Process Technology• Safety, Health, and Environment• Process Instrumentation• The Principles of Quality• PT 1—Equipment• PT 2—Systems• PT 3—Operations• Process Troubleshooting

Additional courses may include:

• Math (one or two classes)• Applied General Chemistry and Physics• College Physics• General or Organic Chemistry• English Composition 1 and 2• Speech• Social Behavioral Science• Computer Literacy• Humanities/Fine Arts• Other technical electives

This chapter focuses on the typical courses found in process technology programs around theworld and provides a foundation upon which future students and educators can build.

Course Description: “Introduction to Process Technology” is a survey of all the courses found inthe process technology curriculum.

Introduction to Process Technology Course Outline:1. History of the Chemical Processing Industry2. Introduction to Process Technology3. Safety, Health, and Environment4. Applied Physics 15. Equipment 16. Equipment 27. Process Instrumentation 18. Process Instrumentation 29. Process Technology (PT) Systems 1

10. Process Technology Systems 211. Industrial Processes12. Process Technology Operations13. Applied General Chemistry 114. Applied Physics 215. Environmental Standards

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16. Quality Control17. Process Troubleshooting18. Self-Directed Job Search19. Applied General Chemistry 220. Chemical Process Industry Overview

2.2 Safety, Health, and Environment

Process safety refers to the application of engineering, science, and human factors to the design andoperation of chemical processes and systems. The primary purpose of process safety is to preventinjuries, fatalities, fires, explosions, and unexpected releases of hazardous materials. Process safetyfocuses on the individual chemical processes and operational procedures associated with these sys-tems. A process safety analysis is used to establish safe operating parameters, instrument inter-locks, alarms, process design, and start-up, shutdown, and emergency procedures. Process safetyprograms cannot completely eliminate risk; they can only control or reduce those risks.

Safety, Health, and Environment courses for process technicians deal with items such as per-sonal protective equipment, hazard communication, permit systems, fire extinguishers, hazardousmaterials and emergency response, following procedures, general safety rules, and equipmentand operation hazards. Safety training is designed to keep employees safe and productive, protectthe community and environment, and protect equipment and physical facilities.

Safety Course Description: Development of knowledge and skills to reinforce the attitudes andbehaviors required for safe and environmentally sound work habits. Emphasis on safety, health,and environmental issues in the performance of all job tasks and regulatory compliance issues.The student will list components of a typical plant safety and environmental program; describe therole of a process technician in relation to safety, health, and environment; and identify and describesafety, health, and environmental equipment uses.

Typical Course Outline:1. Introduction to Process Safety2. Hazard Classification3. Routes of Entry and Environmental Effects4. Gases, Vapors, Particulates, and Toxic Metals5. Hazards of Liquids6. Hazardous Chemical Identification: HAZCOM, Toxicology, DOT7. Fire and Explosion8. Electrical, Noise, Heat, Radiation, Ergonomic, and Biological Hazards9. Operating Hazards: Permits, Emergency Response, HAZWOPER

10. Personal Protective Equipment (PPE)11. Engineering Controls12. Administrative Controls13. Regulatory Overview: OSHA, PSM, EPA

Over the past 30 years, a number of incidents have occurred that have quietly changed the chem-ical processing industry forever. Incidents such as those in Bhopal, Alaska (the Exxon Valdez oilspill), and Texas City (involving BP) have made us aware of the potential for catastrophic events


47

that exists in our modern manufacturing environment. Technological advances in modern manu-facturing are so rapid that many technologies are outdated a few months after they are installed.Process technicians use this technology to control many of their processes. A single operator canremotely control a manufacturing complex from a single control room. Figure 2–3 shows a processtechnician monitoring process conditions.

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(a)

(b)

Figure 2–3 Process Control Room

In 1992, after years of research and investigation into the causes of industrial explosions, fires,and vapor releases, the Occupational Safety and Health Administration (OSHA) and theEnvironmental Protection Agency (EPA) released the Process Safety Management Standard. ThisPSM standard was the government’s response to a number of incidents that had alarmed thechemical processing industry, communities and the public at large, and government. Key elementsof the standard include employee participation, process safety information, operations proce-dures, process hazard analysis, employee training, emergency response, and hot work permitting.

OSHA and the EPA believe that the key to preventing catastrophic emergencies in the chemicalprocessing industry is adequate employee training. This was the conclusion of the governmentalgroups that investigated the Phillips Chemical and ARCO vapor release and explosions. Theemployee training aspect of the PSM standard includes seven sections:

• Process overview• Training records and method used to administer training (documentation of

attendance and competency achieved is required)• Identification of chemicals used in the process• Control of access to and egress from the process unit• Training materials (must reflect current work practices)• Refresher training• Contract labor requirements for informing, training, and documenting

Within months of the release of the PSM standard, industry joined with education to form a numberof industrial partnerships. These early partnerships initiated the development of a new two-yeardegree program, “Process Technology.” The key considerations driving the development of thisprogram were (1) rapid advances in technology, (2) desire to eliminate accidents in the workplace,(3) potential catastrophic risks, (4) new regulations and guidelines from the government, and (5) loss of the Baby Boomer workforce.

Safety programs have a rich tradition inside the chemical processing industry. The CPI has beenvery receptive to establishment and adoption of sound safety principles and government regula-tions. Process technicians must undergo a wide variety of government-mandated training and aresubject to numerous regulations. The following are 10 of the most common safety training issues:process safety management (29 C.F.R. §1910.119); OSHA; hazard communication (29 C.F.R.§1910.1200); HAZWOPER (29 C.F.R. §1910.120); fire fighting (29 C.F.R. §1910.157); permit sys-tem; environmental awareness; departments of transportation; respiratory protection (29 C.F.R.§1910.134); and personal protective equipment (29 C.F.R. §§1910.133, 1910.135).

The hazard communication standard is a central feature in the safe operation of the chemicalprocessing industry. HAZCOM ensures that process technicians can safely handle, transport, andstore chemicals.The standard covers chemical lists, material safety data sheets (MSDS), personalprotective equipment, physical and health hazards, toxicology, hazardous chemicals and opera-tions, manufacturer’s information, and warning labels. Permit systems are designed to protectworkers from hazardous energy, hot work, opening and blinding, confined-space entry, and coldwork. A good permit system can easily be integrated into normal operations to enhance protec-tion of employees, equipment, and the environment.

Fire protection, prevention, and control are principles relating to industrial fires. Process techniciansare required to participate in yearly training using fire extinguishers, monitors, and hoses. During


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these exercises, each member of the team aggressively attacks and extinguishes a variety of fires.Fire prevention educates technicians about fire hazards and steps to take to eliminate them.

2.3 The Principles of Quality Control

During the early 1980s, U.S. industry was taught a valuable lesson in the area of quality improve-ment. Using advanced quality practices, the Japanese captured major economic markets from U.S.counterparts. A decade earlier, American business had refused to listen to several leading qualitythinkers. This lack of vision cost the stockholders of these companies dearly, as Dr. W. EdwardsDeming, Joseph M.Juran, and others took their message to the Japanese.By 1985, all of the leadingoil and automotive giants were listening very closely to what these “quality gurus” had to say.

A basic principle of quality control states that each process has a range that it naturally movesthrough. For example, the normal temperature range for your home may fluctuate between 70 and80 degrees; your desired setpoint may be 75 degrees. Before statistical process control (SPC), anadjustment was made each time the process variable rose above or fell below the setpoint (Figure 2–4). If natural variation is not taken into consideration, the process could be driven com-pletely out of control by the well-intentioned but overreactive adjustments. SPC allows a processto operate within its own variation by making adjustments only after a number of out-of-limitsamples have been caught.

In the Principles of Quality course, students use advanced statistics and mathematics to workwith operational data. Process technicians collect, organize, and analyze data during routine op-erations. The statistical approach works well with statistical process control and control charts.A variety of processes can easily be adapted to fit these quality tools. Examples of these includeequipment and quality variables; process variables include pressure, temperature, flow, level, andanalytical parameters.

Principles of Quality Course Description: Study of the background and application of qualityconcepts. Topics include team skills, quality tools, statistics, economics, and continuous improve-ment. The focus of the course is on the application of statistics, statistical process control, math,and quality tools to process systems and operations.

Typical Course Outline:1. The Quality Gurus2. Total Quality Management (TQM)3. Quality Tools 14. Statistics 15. Statistical Process Control6. Control Charts7. Quality Tools 28. Statistics 29. Variation in Processes

10. Customer Satisfaction11. The Economics of Quality12. Communication—The Critical Skill13. International Standards Organization (ISO)14. Teamwork and Personal Effectiveness

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2.4 Instrumentation and Process Control

Process Instrumentation is a core class designed to teach the process technology student thebasic principles for reading process blueprints, the primary function of instruments, and howinstruments work together to automatically control a process. Process instruments fall into fivedifferent groups: (1) primary elements and sensors, (2) transmitters, (3) controllers, (4) transduc-ers, and (5) final control elements. Figure 2–5 shows various instruments used in the processingindustry.

2.4 Instrumentation and Process Control

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Time

Temperature

08:00 09:00 10:00 11:00 12:00 13:00

70

75

80

85

65

90

14:00 15:00 16:00

Target

Time

Temperature

08:00 09:00 10:00 11:00 12:00 13:00

70

75

80

85

65

90

14:00 15:00 16:00

Target

Adjust Setpoint

NORMAL VARIATION

ADJUSTMENTS + NORMAL VARIATION

COMMENTS: Loweredsetpointto 70˚F

Increasedsetpointto 80˚F

Decreasedsetpointto 77˚F

Decreasedsetpointto 65˚F

Don't knowwhat happened!

Increasing setpointto 85˚F

?

Back in control.Minor adjustment

to 87˚F

Figure 2–4 Temperature Control Before SPC

Each part found in a plant has an equivalent plan symbol or diagram and a specific relationship toother pieces of equipment. Examples of such relationships include:

• Transmitters and controllers• Piping, tanks, and valves• Pumps and compressors• Motors and steam turbines• Heat exchangers and cooling towers• Fired heaters and boilers• Distillation columns and reactors

Process Instrumentation Course Description: Study of the instruments and instrument systemsused in the chemical processing industry; includes terminology, primary variables, symbols anddiagrams, control loops, and basic troubleshooting.The purpose of this class is to provide studentswith an understanding of basic instrumentation and modern process control used in the chemicalprocessing industry. Process instrumentation is taught from the concept of the control loop inrelation to how a process technician runs a unit. (Process instrumentation is one of the eight core

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Figure 2–5 Process Instruments

classes required by the State of Texas for process technology majors.) In process instrumentationclasses, students learn to describe the basic instrumentation used in modern process control;draw and label each of the control loops used in industry (flow, level, pressure, temperature, andanalytical); draw a cascade control loop; describe manual, automatic, and cascade controls; drawa process flow diagram; and create a piping and instrumentation drawing.

Process Instrumentation Course Outline:1. Symbols and Diagrams2. Process Flow Diagrams (PFD)3. Basic Instrumentation 14. Basic Instrumentation 25. Control Loops 16. Control Loops 2—Controllers and Control Modes7. Modern Process Control—Application and Console Operations8. Piping and Instrumentation Drawing 19. Piping and Instrumentation Drawing 2

2.5 Process Equipment

Process training for operators includes an in-depth study of the basic equipment found in thechemical processing industry (Figure 2–6). This knowledge forms a basis for future site-specifictraining activities. Not all of the equipment reviewed in the training program will be found on theunit you will be assigned to, of course. However, the odds indicate that at some time in your workcareer you will come in contact with all of the equipment that you initially study in this course—andmuch more.

Equipment training focuses on five basic skills: (1) familiarity with the equipment and basiccomponents, (2) understanding of how the device operates (scientific principles and technology),(3) equipment relationships within a system, (4) preventive maintenance and troubleshooting,and (5) operation of the equipment. Process technicians are not required to become mechani-cal, instrument, or electrical technicians; however, they are required to have a sound under-standing of the equipment that makes up a particular process. These five basic skills allow atechnician to understand the process and communicate effectively with maintenance and engineering.

Most entry-level training programs cover the following types of equipment:

• Valves, piping, and vessels• Pumps, compressors, fans, and blowers• Steam turbines and motors• Heat exchangers and cooling towers• Boilers and furnaces• Reactors and distillation columns• Instrumentation• Basic hand tools• Lubrication, bearings, and seals• Flares, mixers, and steam traps

2.5 Process Equipment

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Process Technology (PT) 1—Equipment Course Description: Instruction in the use of commonprocess equipment.

Course Outline:1. Introduction to Process Equipment2. Valves3. Piping and Vessels4. Pumps5. Compressors6. Turbines and Motors7. Heat Exchangers8. Cooling Towers9. Boilers

10. Furnaces11. Reactors12. Distillation Columns

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Figure 2–6 Equipment

Heat Exchanger Furnace

Pump

Valve

Distillation Column

2.6 Process Systems

Process Technology 2—Systems is a study of the common industrial processes broken down intosmaller components called systems. A system includes an arrangement of equipment engineeredto perform a specific function. A system can also be characterized as a collection of equipment thatworks together to produce a product. An example of this is a pump system that includes pipes,valves, instruments, a pump, and a tank.The purpose of this system is to transfer a liquid from oneplace to another. This grouping of equipment can be used in a wide variety of systems.

Although a large number of systems and equipment exist, most college programs focus on theequipment most commonly used in their geographic area. Until 1990, systems training was left upto the chemical processing industry, as site-specific, on-the-job training. An average, full-time, work-ing process technician would spend several years studying the different systems in his or her plant.

Process systems take their specific characteristics from the equipment that makes up the processunit. Some of the basic systems found in the chemical processing industry include:

• Pump-around system• Compressor (air or gases) system• Heat exchanger and cooling tower system• Lubrication system• Electrical system• Furnace system• Plastics system• Reactor system• Steam generation system• Distillation system• Refrigeration system• Water treatment system• Process control system

Modern manufacturing plants are comprised of complex networks that work closely with each other.The people who operate and maintain these networks include process technicians, maintenancetechnicians, instrument technicians, electricians, computer, laboratory technicians, chemists, andengineers.

PT 2—Systems Course Description: Study of common process systems found in the chemicalprocess industry, including related scientific principles. Includes the study of pumps and compressorsystems, heat exchangers and cooling towers, boilers and furnace systems, distillation systems,reaction systems, utility systems, separation systems, plastics systems, instrument systems, watertreatment systems, and extraction systems. A hands-on lab gives students an opportunity to workwith glass bench-top distillation units, start up and shut down a debutanizer unit from a computerconsole, and operate a distillation pilot plant.

Typical Course Outline:1. Instrumentation and Process Control Systems2. Pump and Compressor Systems

2.6 Process Systems

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56


FT

IP

Ti

Pi

FR

FIC

AT

TR

Hot OilInsulated Tank

ºF

ºF

FO

HEAT EXCHANGER #1

HEAT EXCHANGER #2

TAH

TiTi

Ti

Pi

Pi

%

%

SPPVOP%

GPM

GPMSPPVOP%

IP

TIC TETT

Pi

Pi

Pump

Pump

Fi

Figure 2–7 Heat Exchanger System

2.7 Process Operations

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3. Heat Exchanger and Cooling Tower Systems4. Boiler and Furnace Systems5. Distillation Systems6. Reactor Systems7. Utility Systems8. Extraction and Other Separation Systems9. Plastics Systems

10. Other Systems

Heat transfer is an important process used in the chemical processing industry. A heat exchangeris a device used to transfer heat energy from a hotter fluid to a cooler fluid. Heat exchangers comein a variety of designs, including shell and tube, air-cooled, spiral, and plate. Heat exchangers usethe principles of conductive and convective heat transfer. A shell-and-tube heat exchanger systemconsists of shell in and out piping; tube in and out piping; valves; instruments; flow, temperature,analytical, and pressure control loops; and two separate pump systems. Figure 2–7 illustrates thebasic components of a heat exchanger system.

A distillation process is a complex arrangement of systems that includes: cooling tower system,pump and feed system, heat exchanger system, product storage system, compressed air system,steam generation system, and complex instrument control system (see Figure 2–8). Each of thesesystems is designed to support a specific part of the distillation process. Distillation is a processthat separates the various components in a mixture based on the differences in their volatilities(each chemical substance has a unique boiling point). In this type of system, a distillation columnis the central piece of equipment. College faculty focus on how to operate these systems with mod-ern process control, using various labs and hands-on teaching opportunities.


Process Technology 3—Operations is an applied learning course that allows a technician tooperate a working unit. These working units come in a variety of shapes and designs dependingon the college or university. The key is the application of classroom skills to process equipmentand systems. Process technicians collect, organize, and analyze data by catching samples andmonitoring operating equipment. PT 3—Operations is an advanced course that provides a seriesof challenges to adult learners, such as working in a self-directed work team, troubleshooting prob-lems, starting up and shutting down equipment, following safety procedures, and developingoperational procedures. Ideally, the operations course students have access to an operating uniteither at the college or a local industry. The class is designed to closely represent the first threemonths of working in the chemical processing industry. For example, Figure 2–9 illustrates thecomponents found in a simple reactor operation.

PT 3—Operations Course Description: This course combines systems into operational processeswith emphasis on operation under various conditions. Topics include typical duties of an operator.Instruction focuses on the principles of chemical engineering and process equipment. Emphasison scale-up from laboratory bench to pilot unit. Describe unit operation concepts; solve elemen-tary chemical mass/energy balance problems; interpret analytical data; and apply distillation andfluid flow principles. The purpose of this class is to provide adult learners with the opportunity towork in a self-directed work team, operate a complex distillation system, collect and analyze data,

start and stop process equipment, and follow and write operational procedures. The course isadvanced and requires the learner to apply classroom skills to real-life operational activities.Students are required to qualify and operate a process unit and perform the following steps:

• Orientation to and overview of the operating unit• Safety, health, and environment review• On-the-job training in drawing process flow diagrams• Develop and use standard operational procedures• Work in self-directed teams• Complete operational assignments• Collect, organize, and analyze data

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• Troubleshoot process problems• Complete the qualification process and a written exam• Operate the process unit (required), including start-up and shut-down

Typical Course Outline:1. Orientation and Overview of Unit (includes all safety aspects)2. Draw Simple Process Flow Diagrams of Operating Unit (includes listing primary equipment,

flows, and instrumentation)3. Complete Line Tracing and Initial Training4. Complete Basic Equipment, Instruments, and Flows Assessment Exam5. Work in Team Assignments by Initial Assessment Ranking


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6. Complete Team Assignments– Write start-up procedures– Write and develop a team checklist– Record daily activity in technical notebook– Complete operational directives

7. Complete Individual Walk-Through Checklist with Instructor8. Complete Final Exam and Turn in Technical Notebook

2.8 Troubleshooting

Process Troubleshooting is an important part of a technician’s job description. This course isadvanced and has a high degree of analytical difficulty. A process technician’s role can becompared to that of a jet fighter pilot. The pilot not only needs to be familiar with the aircraft, butmust also be able to use it in a variety of combat situations. The skills needed to make a goodfighter pilot are the same skills required to make a good process technician.Troubleshooting skillsvary significantly between technicians. Some technicians are content with simply knowing aboutthe equipment and systems they operate and how to start them up and shut them down. Othertechnicians have the rare ability to move far beyond simply operating the unit: they quickly identifyproblems and apply corrections. These few technicians are highly valued by their employersbecause they are a critical component in keeping the unit running safely and efficiently.

Troubleshooting the operation of process equipment requires a good understanding of complex op-erations and how the equipment and systems operate. Equipment used in modern manufacturing isrun 24 hours a day, 7 days a week, 52 weeks a year.Routine maintenance is performed on this equip-ment during scheduled maintenance times. Process technicians should attempt to uncover as muchinformation as possible about the equipment in their units. Much of this information can be found intechnical manuals, checksheets, SPC charts, or the operating manuals. Manufacturer information istypically included in the engineering specifications, drawings, and equipment descriptions.

Process Troubleshooting ModelsOne of the highest levels a process technician can achieve is the ability to clearly see the processand sequentially break down, identify, and resolve process problems. Process troubleshooting hastraditionally been considered the area of senior technicians, although some people believe thatsuccessful techniques can be taught to all technicians. Experience has proven over time to be thebest teacher on equipment that is manually operated; however, new computer technology providesadvanced control instrumentation that can be used to quickly and methodically track down processproblems. It is well known that a single problem can have a cascading effect on all surroundingequipment and instrumentation. This phenomenon is commonly associated with both primaryproblems and secondary problems.

Troubleshooting models are attached to equipment and systems presently being studied at everycommunity college and university that teaches process technology. The 10 models commonlyused to teach process troubleshooting include:

• Distillation model• Reaction model• Separation model

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• Pump and tank model• Compressor model• Heat exchanger model• Cooling tower model• Boiler model• Furnace model• Multiple-variable (multi-variable) model

These 10 models provide the hardware or framework within which the various troubleshootingmethodologies are applied. Each model has a complete set of process control instrumentation andequipment arrangements. A complete range of troubleshooting scenarios has been developed andis typically included with these models. Other models used include stripping and adsorption,decanting, and gas and oil recovery.Figure 2–10 is an example of a multiple-variable process model.

Troubleshooting MethodsA number of troubleshooting methods can be used with these models. Methods vary dependingon individual educational faculty, consultants, and industry. The basic approach to most methodsincludes the development of a good educational foundation.

1. Method One: Educational (Completed in College Program)• Gain basic knowledge of the equipment and technology• Understand the math, physics, and chemistry associated with the equipment• Study equipment arrangements in systems• Study process control instrumentation• Operate equipment in complex arrangements• Troubleshoot process problems

2. Method Two: Instrumental (Completed in College Program)• Gain basic understanding of process control instrumentation• Gain basic understanding of the unit process flow plan• Advanced training in controller operation (PLC (programmable logic controller) and DCS

(distributed control system))• Troubleshoot process problems

3. Method Three: Experiential (Completed on the Job)• Experience operating specific equipment and system• Gain familiarity with past problems and solutions• Develop ability to think outside the box and innovate• Apply critical thinking; identify and challenge assumptions• Evaluate, monitor, measure, and test alternatives• Troubleshoot process problems

4. Method Four: Scientific (Requires Engineering Technology, Process Technology, Experience,and High Aptitude)• Have good grounding in principles of mathematics, physics, and chemistry• Understand theory-based operations• Have good understanding of equipment design and operation• View the problem from the outside in• Use outside information and expertise and reflective thinking• Generate alternatives, do brainstorming, and rank alternatives• Troubleshoot process problems

2.8 Troubleshooting

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Statistics, Statistical Process Control, and Quality ToolsData collection, organization, and analysis are another approach that can be used to troubleshootprocess problems. Check-sheets are used to collect large quantities of data.This quantitative datacan be organized into graphics or trends to plot process variation or changes. Data analysis utilizesa variety of quality techniques to put all of the parts in place. Control charts are frequently used toassist process technicians in operating a complicated process. Quality tools include a variety ofmethods designed to improve product quality.

Troubleshooting Course Description: Instruction in the different types of troubleshooting tech-niques, methods, and models used to solve process problems. Topics include application of datacollection and analysis, cause-effect relationships, and reasoning.

Course Outline:1. Introduction to Process Instrumentation and Troubleshooting2. Process Symbols and Diagrams3. Understanding Process Equipment Relationships4. Introduction to Control Loops5. Statistics, Quality Tools, and Troubleshooting6. Control Charts7. Introduction to Process Troubleshooting8. Pump Model9. Compressor Model

10. Heat Exchanger Model11. Cooling Tower Model12. Boiler Model13. Furnace Model14. Distillation Model15. Reactor Model16. Separation Model17. Multiple-variable Plant

2.9 Applied General Chemistry and Physics

Applied general chemistry and physics are two fundamental courses that have been recom-mended by industry for inclusion in process technology programs. It is clear that informationcontained in academic chemistry and physics courses does not address key topics required by theoccupation. Also, the process safety management standard requires that process technicianshave an understanding of the chemistry and physics associated with the processes they areoperating. Figure 2–11 demonstrates how adult learners can use hands-on bench-top operationsto understand the science associated with difficult topics.

Process technicians frequently mix chemicals together under a variety of conditions to producenew products. These chemical mixtures may be heated, cooled, blended, passed over a catalyst,or distilled. The chemistry associated with these processes may be simple, or may be quite com-plex. Documentation associated with these mixtures should be designed so that a new technicianwill be able to understand the basic chemistry.

2.9 Applied General Chemistry and Physics

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Common chemistry and physics topics include:

• Pressure• Temperature• Fluid flow• Heat transfer• Heat and energy• Density• Viscosity• Specific gravity• Reactors• Atoms and elements• Bonding• Molecules• Compounds• Solutions

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Figure 2–11 Bench-top Operation

• Mixtures• Hydrocarbons• Distillation• Matter

Process technicians need to understand the chemistry and physics of the operations andprocesses they work with. Associated with each piece of equipment or system is a series ofscientific principles. These principles include, among other things, fluid flow, reactions, heattransfer, temperature, distillation, gas laws, pressure, electricity, mechanical rotation, materialbalance, pH measurements, density, specific gravity, the periodic table of elements, and organicchemistry. The full list is much longer than this; the more technicians know, the better the productthey will produce and the safer their work environment will be.

It is difficult to separate chemistry and physics. Some colleges combine applied chemistry andphysics into one course; others have two separate courses. Almost all require either a naturalscience chemistry or physics course as a prerequisite; a few require both. Completion of thesecourses helps round out a technician’s academic and technical training. Completion of thesecourses also makes it easier for process technicians and engineers to communicate effectively.

Applied General Chemistry Course Description: Study of the general concepts of chemistry withan emphasis on industrial applications. Student will measure physical properties of matter,perform chemical calculations, describe atomic and molecular structures, distinguish periodicrelationships of elements; name and write inorganic formulas; write equations for chemical reac-tions; demonstrate stoichiometric relationships; and demonstrate basic laboratory skills.

Course Outline:1. Pressure and Characteristics of Fluids2. Temperature, Heat Transfer, and Associated Math3. Fundamentals of Chemistry and the Periodic Table4. Chemical Reactions, Material Balance, % by Weight, pH5. Fundamental Concepts of Physics; Density, Specific Gravity, Pressure6. Complex and Simple Machines, Electricity, Magnetism7. Advanced Concepts of Chemistry—Distillation8. Chemical Bonds, Fluid Flow, Gas Laws, and Heat9. Organic Chemistry—Alkanes, Chemical Etymology

– Carbon and hydrogen, chemical equations– Alkenes and alkynes, aromatic– Alcohols, phenols, esters, halides, aldehydes– Ketones, carboxylic acids, amines, amides

2.10 College Math

Math requirements vary from college to college, but a standard exists between institutions. Themajority of community colleges require only one or two math courses. Most universities requirestudents to take at least one math course beyond college algebra. Manufacturing engineeringtechnology, a field closely related to process technology, requires three to five math courses.Typically, process technology programs include one applied or academic math course; one applied

2.10 College Math

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general chemistry course or one applied physics course; and one natural science course, eitherphysics or chemistry. The courses commonly used to fulfill these requirements include:

• Basic Mathematics and Pre-Algebra (depending on student preparation)• Technical Algebra or College Algebra

– Optional: Technical Math 2 or Academic Math• Applied General Chemistry or Physics• Academic Physics or Chemistry

– Optional: Statistics (typically covered in principles of quality)

Summary

“Introduction to Process Technology” is a survey course that covers all of the courses found in theprocess technology curriculum and degree. This course is designed as an overview and shortsynopsis of common elements found in each course.

Process safety is described as the application of engineering, science, and human factors to thedesign and operation of chemical processes and systems. Safety courses for process techniciansdeal with use of safety equipment, process safety analysis, and the prevention of injuries, fatali-ties, fires, explosions, or unexpected releases of hazardous materials. Safety training is designedto keep employees safe and productive, protect the community, environment, and protectequipment and physical facilities.

In a “Principles of Quality” course, process technicians collect, organize, and analyze data duringroutine operations, and study the background and application of quality concepts. Topics includeteam skills, quality tools, statistics, economics, and continuous improvement. The focus is on theapplication of statistics, statistical process control, math, and quality tools to process systems andoperations.

Process training for operators includes an in-depth study of the basic equipment found in thechemical processing industry. Equipment training focuses on five basic skills: (1) familiarity withthe equipment and basic components, (2) understanding the operation of the device (scientificprinciples and technology), (3) equipment relationships within a system, (4) preventive mainte-nance and troubleshooting, and (5) operating the equipment.

A process is a collection of equipment that works together to produce a product. Some of the basicsystems found in the chemical processing industry include the pump-around system, compressorsystem, heat exchanger and cooling tower system, boiler and furnace, distillation, separations andreactions. Process technology operations is an applied learning course that allows a technician tooperate a working unit. It provides a series of challenges to adult learners, such as working in aself-directed work team, troubleshooting problems, starting up and shutting down equipment,following safety procedures, and developing operational procedures.

Process instruments fall into five different groups: (1) primary elements and sensors, (2) transmit-ters, (3) controllers, (4) transducers, and (5) final control elements.

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Process troubleshooting, which is an important part of a process technician’s job description,incorporates three basic components: knowledge of the equipment, instrumentation, and technology;understanding of the scientific principles associated with your unit; and an understanding of a basictroubleshooting system. The basic tools used in troubleshooting include checklists, control loops,data collection, SPC charts, flow charts, brainstorming, systems knowledge, and scientific principles.Ten common models are used to teach process troubleshooting: distillation model, reaction model,separation model, pump and tank model, compressor model, heat exchanger model, cooling towermodel, boiler model, furnace model, and multi-variable model. These models provide the hardwareor framework within which the various troubleshooting methods are applied.

Common chemistry and physics topics include pressure, heat transfer, viscosity, atoms and elements,compounds, hydrocarbons, temperature, heat and energy, specific gravity, bonding, solutions, distil-lation, fluid flow, density, reactions, molecules, compounds, mixtures, and matter.

College mathematics courses for process technicians typically focus on common applied opera-tions.Variations on basic math, algebra, trigonometry, physics, chemistry, and statistics are woveninto the daily technician routines.

Summary

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Chapter 2 Review Questions1. List the basic concepts of modern quality control.

2. List the basic concepts taught in safety, health, and environment courses.

3. List three basic systems found in the chemical processing industry.

4. List the basic concepts taught in process operations courses.

5. List the basic concepts taught in process instrumentation courses.

6. List the basic concepts taught in process troubleshooting courses.

7. Describe how science and chemistry are related to the other process classes.

8. Explain why a good mathematical foundation is important to a process technician.

9. List the basic concepts taught in introduction to process technology courses.

10. List the basic concepts taught in the process equipment course.

11. Describe the process technology curriculum and Associate of Applied Science degree planat your school.

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Safety, Health,and EnvironmentAfter studying this chapter, the student will be able to:

• Explain the basic principles of safety, health, and environment.• Describe the general safety rules used by chemical processing plants.• Discuss the process safety management (PSM) standard.• Describe the hazard communication standard.• Discuss physical and health hazards.• Explain toxicology and the terms associated with it.• Describe air-purifying and air-supplying respirators.• Describe personal protective equipment and the four levels of PPE.• Describe typical plant permit systems.• Describe the principles of fire prevention, protection, and control.• Evaluate the different types of fire extinguishers.• Describe HAZWOPER.• Explain the principles of hearing protection.• Describe the sections of the DOT.

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Chapter 3 ● Safety, Health, and Environment

Key TermsAir-purifying respirator—breathing device that mechanically filters or absorbs airbornecontaminants.

Air-supplying respirator—breathing device that provides the user with a contaminant-freeair source.

Department of Transportation (DOT)—governmental agency empowered to regulate thetransportation of goods on public roads and highways.

Emergency response—how specific individuals act during an emergency situation; theemployer must have a written plan setting out and documenting these actions.

First responder—person who undertakes the first two levels of emergency response as de-scribed by HAZWOPER (29 C.F.R. §1910.120). The first responder awareness and operations lev-els set out a series of structured responsibilities. The awareness level teaches a technician howto recognize a hazardous chemical release, the hazards associated with the release, and how toinitiate the emergency response procedure. The operations level teaches a technician how tosafely respond to a release and prevent its spread.

Hazard communication (HAZCOM) standard—known as “workers’ right to know,” ensuresthat process technicians can safely handle, transport, and store chemicals.

HAZWOPER—hazardous waste operations and emergency response.

Lock-out/tag-out—term used to describe a procedure for shutting down and making unavail-able for use equipment that falls under the control of hazardous energy regulations (29 C.F.R.§1910.147).

Permit system—a regulated system that requires a variety of permits for various applications.The most common applications are cold work, hot work, confined space entry, opening/blinding,permit to enter, and lock-out/tag-out.

Personal protective equipment (PPE)—gear used to protect a technician from hazardsfound in a plant. OSHA and EPA have identified four levels of PPE that could be requiredduring an emergency situation. Level A provides the most protection; level D provides theleast.

Physical hazard—name for a chemical that statistically falls into one of the following cate-gories: combustible liquid, compressed gas, explosive or flammable, organic peroxide, oxidizer,pyrophoric, unstable, or water reactive.

Process safety management (PSM) standard—governmentally set rules designed to preventthe catastrophic release of toxic, hazardous, or flammable materials that could lead to a fire,explosion, or asphyxiation.

Respiratory protection—a standard or program designed to protect employees from airbornecontaminants.

3.1 Safety, Health, and Environment Overview

In the past few decades, a number of occurrences have changed the chemical processing indus-try (CPI) forever. Incidents like those in India, Texas, and Alaska have made us aware of the po-tential for catastrophic events that exists in our modern manufacturing environment. The rapidadvances in technology mean that a single process technician may be remotely controlling a com-pany’s vast equipment resources from a single control room, even if he or she is not yet thoroughlyacquainted with the new equipment being used in the plant’s systems.

In 1992, the Occupational Safety and Health Administration (OSHA) and the Environmental Pro-tection Agency (EPA) jointly released a process safety management (PSM) standard. The PSMstandard was developed in response to a number of incidents that had alarmed the chemical pro-cessing industry, community, and government, and was based on years of research and investi-gation into the causes of industrial explosions, fires, and vapor releases. Key elements of thestandard include employee participation, process safety information, operations procedures,process hazard analysis, employee training, emergency response, and hot work permitting.

Both OSHA and the EPA believe that the key to preventing catastrophic emergencies inside thechemical processing industry is adequate employee training. This was the conclusion of the gov-ernmental groups that investigated the Phillips Chemical Company and ARCO vapor release andexplosions. The employee training aspect of the PSM standard includes seven sections:

• Process overview• Training records and method used to administer training (attendance and competency

achieved must be documented)• Identification of chemicals used in the process• Control of access to and from the process unit• Requirements that training materials reflect current work practices• Refresher training• Contract labor requirements (contract labor must inform, train, and document that training)

Within months of the release of the PSM standard, industry joined with education to form a num-ber of industrial partnerships. These early partnerships led to the development of a new two-yeardegree program in “Process Technology.” The key reasons driving the development of this programwere: (1) rapid advances in technology, (2) desire to eliminate accidents in the workplace, (3) po-tential catastrophic risks, (4) new regulations and guidelines from the government, and (5) loss ofthe Baby Boom workforce.

Safety programs have a rich tradition inside the chemical processing industry, and the CPI hasbeen very receptive to adopting sound safety principles and government regulations. Processtechnicians are subject to a wide variety of government-mandated training and regulations. Thefollowing are 10 of the most common safety training issues:

• Process safety management (29 C.F.R. §1910.119)• OSHA• Hazard communication (29 C.F.R. §1910.1200)• HAZWOPER (29 C.F.R. §1910.120)

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3.1 Safety, Health, and Environment Overview

• Firefighting (29 C.F.R. §1910.157)• Permit system• Environmental awareness• Department of Transportation• Respiratory protection (29 C.F.R. §1910.134)• Personal protective equipment (29 C.F.R. §§1910.133 and 1910.135)

The hazard communication (HAZCOM) standard is a central feature in the safe operation of thechemical processing industry. HAZCOM ensures that process technicians can safely handle,transport, and store chemicals.The standard mandates that workers have access to chemical lists,material safety data sheets, information on physical and health hazards, toxicology, hazardouschemicals and operations, manufacturers’ information, and warning labels. It also sets require-ments for availability and use of personal protective equipment.

Permit systems are designed to protect workers from dangers involved in hazardous energy,hot work, opening and blinding, confined-space entry, and cold work. A good permit system caneasily be integrated into normal operations to protect employees, equipment, and theenvironment.

The principles of fire protection, prevention, and control are designed to provide protection fromindustrial fires. Process technicians are required to participate in yearly training during which tech-nicians are educated about fire hazards and the steps to take to eliminate them. These trainingsessions also include hands-on practice in extinguishing fires.

3.2 Basic Safety Principles

The philosophy behind most modern safety programs involves the prevention of accidents. Suc-cessful accident prevention depends on three basic elements: safe working environments, safeworking practices, and effective leadership. Safety programs for process technicians usually in-clude elements of the following topics:

• HAZCOM—workers’ right to know about the chemicals they use• HAZWOPER—hazardous waste operations and emergency response• Respiratory protection• Permit system• Process safety management• Personal protective equipment• Hearing conservation• Fire prevention and protection• Department of Transportation (DOT) rules and regulations• Environmental standards• Basic principles of safety and contractor safety• Lock-out, tag-out, and confined-space awareness

General safety rules are designed to protect human life, the environment, and physical equipmentor facilities. Before a new technician even enters a refinery or chemical plant, a simple overviewof the general plant safety rules is conducted. These rules include:

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1. Do not go to a fire, explosion, accident, or vapor release scene unless you have specificduties or responsibilities there.

2. Obey all traffic rules.3. Do not park in designated fire lanes.4. Report injuries immediately.5. Stay clear of suspended loads.6. Smoking and matches are not permitted in most sections of a plant.7. Drink only from designated water fountains and potable water outlets.8. Use the right tool for the right job.9. Report to the designated equipment owner before entering an operating area. Stay in your

assigned area.10. Illegal drugs and alcohol are not permitted in the plant.11. Firearms and cameras are not allowed in the plant.12. Take steps to remove hazardous conditions.13. Review and follow all safety rules and procedures, including those relating to:

• personal protective equipment• hazard communication• respiratory protection• permit system• hazardous waste operations and emergency response• housekeeping• fire prevention

14. Know and understand the alarms and rules associated with:• vapor release• fire or explosion• evacuation• all-clear notifications

3.3 Occupational Safety and Health Act

In 1970, a landmark piece of legislation was passed that made safety and health on the job inthe chemical processing industry a matter of federal law. The Occupational Safety and HealthAct (OSHA) brought in sweeping changes that affected 4 million American businesses and,more importantly, 57 million employees and their families. Why was this legislation needed? In1969, 2.5 million disabling injuries and 14,000 deaths were directly linked to safety and healthviolations.

The purpose of OSHA is (1) to remove known hazards from the workplace that could lead toserious injury or death, and (2) to ensure safe and healthful working conditions for American work-ers.The scope and coverage of the legislation are extensive.The Occupational Safety and HealthAct applies to four broad categories: agriculture, construction, general industry, and maritime.Three primary agencies are responsible for administration of the Occupational Safety and HealthAct (see Figure 3–1):

1. National Institute for Occupational Safety and Health (NIOSH)2. Occupational Safety and Health Administration (OSHA)3. Occupational Safety and Health Review Commission (OSHRC)

3.3 Occupational Safety and Health Act

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Figure 3–1 OSHA

3.4 The PSM Standard

After the ARCO and Phillips plant explosions in 1989 and 1990, OSHA and the EPA went to workon a new standard that would limit the possibility of such problems happening again. After yearsof research and investigation into the causes of industrial explosions, fires, and vapor releases,the government issued the process safety management (PSM) standard. Figure 3–2 illustratesthe key elements of the standard.

3.5 The Hazard Communication Program

Government Mandate: Hazard Communication (29 C.F.R. §1910.1200)A fundamental principle of the chemical hazard communication (HAZCOM) program is that in-formed people are less likely to be injured by chemicals and chemical processes than uninformedpeople. According to the standard, all of the chemical inventories and processes within a chemi-cal plant or refinery must be evaluated for potential hazards and risks. Where a risk is found, es-sential information and training are required for all people affected. A chemical HAZCOM programis composed of two essential parts: the written program (which addresses chemical manufactur-ers) and employee training (Figure 3–3).

Requirements of the Standard (Documentation)Because the chemical processing industry manufactures chemicals and employs technicians, theCPI is responsible for both sections of the OSHA standard that addresses chemical manufactur-ers’ employer requirements and user responsibilities.

Chemical manufacturers are required by the HAZCOM standard to:• Analyze and assess the hazards associated with each chemical, and develop written

procedures for evaluating chemicals.• Document the hazard, and develop material safety data sheets (MSDS) and warning

labels.

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OSHAOCCUPATIONAL

SAFETY & HEALTH ACT

● Independent Agency● Conducts Hearings on Contested Issues● Assesses Penalties, Conducts Investigations, Supports or Modifies or Overturns OSHA

Occupational Safety &Health Review Commission

● Investigates Catastrophies & Fatalities● Establishes Standards & Penalties● Inspects Workplaces

OSHAOccupational Safety

& Health Administration

OSHRC

● Safety & Health Research

● Recommends New Standards

NIOSHNational Institute for

Occupational Safety & Health

Figure 3–2 Process Safety Management

• Disseminate the information to affected individuals.• Label, tag, and attach warning documentation to chemicals leaving the workplace.

Employers are responsible for the development of a written hazard communication program, ahazardous chemical inventory list, and associated material safety data sheets. This written pro-gram should be designed so that it is given to the new employee upon initial assignment.The ma-terials should be site specific, readily accessible by plant personnel, and include an evergreenfeature that will keep it up to date. Employers are also required to provide training to employees

3.5 The Hazard Communication Program

75

EMPLOYEE PARTICIPATION● Written program ● How employees will access

ihazard identification system — identify hazards — gather information — communication system

PROCESS SAFETY● Process flow diagram● Equipment, process description, limitations● Consequences of deviation● Safety and relief devices● Electrical classifications● Characteristics of chemicals● Process chemistry● Mixing chemicals

OPERATIONS PROCEDURES● Operations and maintenance● Reflect current work practices● Process properties● Hazards● Start-up, shutdown● Change of chemicals

EMPLOYEE TRAINING● Process overview● Training records and methods● Attendance and competency● Training materials reflect current work practices● Control access to unit● Refresher training● Contractors must inform and train their employees and document that training

PROCESS HAZARD ANALYSIS● SOP, safety, training up front ● Identify unit hazards● Identify causes and consequences — fires — vapor releases — explosions

INCIDENT INVESTIGATIONFor catastrophic events:● Assemble team within 48 hours ● Address all findings● Correct action items

HOT WORK PERMIT● Protect from fires and explosions● Specific procedures for hot work● Defined as welding, cutting, spark producing

EMERGENCY PLANNING● Emergency response plan — designated meeting points — key contacts● Emergency response - roles and responsibilities● Written action plans

Figure 3–3 HAZCOM

76


HAZCOM29 C.F.R. §1910.1200

OSHA

● Analyze Chemical Hazards● Develop Written Procedures for Evaluating Chemicals● Document Hazards● Develop MSDS & Warning Labels● Disseminate Information ● Label, Tag, Attach Documentation to Chemicals Leaving Workplace

● Chemical Hazards● Physical Hazards● Product Identification● PPE● Storage & Handling● Reactivity

● Hazardous Chemicals● Hazardous Operations

● Plant Chemical Inventory List● Provided to All Employees● Toxicology

● Combustible● Flammable● Explosive● Compressed

● Oxidizer● Pyrophoric● Unstable● Water Reactive

● Hard Hat● Safety Glasses● FRC● Monogoggles

● Respirators● Gloves● Safety Shoes● Radio

● Methods Used to Detect the Release of Hazardous Chemicals● Human Senses ● Detectors

● Carcinogen● Mutagen● Teratogen● Asphyxiation

● Corrosive● Toxic● Neurotoxic● Target Organ Effects

HAZCOM PROGRAMmust include: ● Container labeling and warnings ● MSDS ● Employee training

EMPLOYEE TRAININGWRITTEN PROGRAM(Documentation)

Chemical Manufacturers

Chemical Lists

Material Safety Data Sheets

Physical Hazards

Chemical Hazards

Personal Protective Equipment

Release DetectionTarget Critical Operations

about the hazards of the chemicals they will be working with, how to read an MSDS, how to se-lect and use personal protective equipment, and how to read and use one of the three standardlabeling systems: Department of Transportation (DOT), Hazardous Materials Identification System(HMIS), and National Fire Protection Association (NFPA).

Delivery of the Standard to EmployeesThe HAZCOM standard requires an employer to provide information or training to employeesabout their plant’s hazard communication program. Fundamental information that must be givento a process technician includes: the key elements of the HAZCOM standard; the plant’s writ-ten hazard communication program; a detailed hazardous chemical inventory list; and associ-ated material safety data sheets, along with warning labels, tags, and signs. Information shouldbe included on how to access the HAZCOM system, chemical inventory list, and MSDS 24 hours a day, 7 days a week. Employers are required by law to provide open access to HAZ-COM materials.This is why the HAZCOM standard is frequently referred to as the “workers’ rightto know act.”

The chemical processing industry initiates the delivery of HAZCOM training when a technician isfirst assigned to the plant.Training focuses on the physical and health hazards associated with ex-posure to chemicals. Additional information is provided on toxicology, physical properties of thechemicals, and hazards associated with handling, storing, and transporting chemicals. New tech-nicians are required to review company procedures used to protect employees from hazardouschemicals, and specific operations are identified that may expose an employee to a chemical.Thetraining section also includes the selection and use of personal protective equipment and themethods and observations used to detect the release of hazardous chemicals.

3.6 Safe Handling, Storage, and Transportation of Hazardous Chemicals

Process technicians who transport, store, and handle chemicals must understand the systems,equipment, and technology they are working with; the physical hazards associated with chemicals intheir facility; the health hazards associated with chemicals in their facility; chemical routes of entry intothe human body;use of the material safety data sheets;and proper usage of labeling, signs, and tags.

3.7 Physical Hazards Associated with Chemicals

A physical hazard is defined as a chemical that falls into one of the following categories:• Combustible liquid—has a flash point between 100°F (38.8°C) and 200°F (93°C)• Compressed gas—has a gauge pressure of 40 psig at 70°F (21.1C°)• Explosive—a chemical characterized by the sudden release of pressure, gas,

and heat when it is exposed to pressure, high temperature, or sudden shock• Flammable gas—forms a flammable mixture with air at ambient temperature• Flammable liquid—has a flash point below 100°F (37°C)• Organic peroxide—explodes when temperature exceeds a specified point

3.7 Physical Hazards Associated with Chemicals

77

• Oxidizer—a chemical that promotes combustion in other materials through the rapidrelease of oxygen, usually resulting in a fire

• Pyrophoric—a chemical that ignites spontaneously with air at temperatures below130°F (54.4°C)

• Unstable—a chemical that will react (condense, decompose, polymerize, or becomeself-reactive) when it is exposed to temperature, pressure, or shock

• Water reactive—a chemical that reacts with water to form a flammable or hazardous gas

3.8 Health Hazards Associated with Chemicals

One or more of the following health hazards may be associated with chemicals that the processtechnician works with:

• Carcinogen—known cancer-causing substance• Mutagen—a chemical that is suspected to have the properties required to change or

alter the genetic structure of a living cell• Teratogen—a substance that is suspected to have an adverse effect on the develop-

ment of a human fetus• Reproductive toxin—a chemical that inhibits the ability of a person to have children;

chemicals are routinely tested for this property• Asphyxiation—occurs when oxygen is removed or displaced by a chemical or when a

chemical blocks or impedes the ability of a person’s body to use oxygen• Anesthetic—dulls the senses (e.g., alcohol)• Neurotoxin—slows down brain function (e.g., lead and mercury)• Allergic response—a negative reaction to a chemical that triggers a physical re-

sponse of discomfort, injury, or death• Irritant—chemical that causes temporary discomfort when it comes into contact with

human tissue• Sensitizer—a chemical that affects the nerves (e.g., phenol is absorbed through the

skin and will sensitize the affected area)• Corrosive—a chemical that causes severe damage to human tissue (e.g., sulfuric

acid)• Toxic—a chemical that has been determined to have an adverse health impact• Highly toxic—a chemical of which only a small amount is lethal• Target organ effects—a chemical that contacts the body at one location (e.g., a hand)

and is transferred to another area of the body where it has an adverse effect on aspecific organ

Hazardous chemicals can enter the human body through:• Inhalation• Absorption (skin contact)• Ingestion• Injection

Physical hazards and health hazards in a chemical plant or refinery must be quickly recognizableto process technicians. Recognizing a hazard and knowing how to respond are key elements of atechnician’s training. Figure 3–4 illustrates this.

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3.9 Material Safety Data Sheets

It has been estimated that one out of every four workers in the United States handles a chemical.Development of the material safety data sheet (MSDS) for each chemical is the responsibility ofthe chemical manufacturer. A typical material safety data sheet has nine or ten sections, as follows:

1. Product Identification and Emergency Information2. Hazardous Ingredients3. Health Information and Protection or Hazards Identification4. Fire and Explosion Hazard5. Physical Data and Chemical Properties6. Spill Control Procedure7. Regulatory Information8. Reactivity Data9. Storage and Handling

10. Personal Protective Equipment

3.10 Toxicology

Toxicology is the science that studies the noxious or harmful effects of chemicals on living sub-stances.The fundamentals of toxicology include a relationship between dose and response. Doseis the amount of chemical entering or being administered to a subject. Response is the toxic effectthe dose has on the subject.

3.11 Respiratory Protection Programs

The Occupational Safety and Health Administration requires employers who use and issue respi-rators to develop a written respiratory protection program. Employees must receive proper train-ing in respiratory protection. Process technicians use two basic types of respirators: (1) airpurifying, and (2) air supplying.

3.11 Respiratory Protection Programs

79

DANGERTOXIC

HAZARD

Figure 3–4 Hazard Recognition

Air-Purifying RespiratorsAir-purifying respirators are either half-face or full-face. Half-face air-purifying respirators are de-signed to cover the mouth and nose. In contrast, full-face respirators form a positive seal aroundthe eyes, nose, and mouth. These respirators are designed to remove specific contaminants ororganic vapors from the air. Concentrations of these contaminants may range from 5 to 50 timesthe normal exposure limit allowed by law.

Air-Supplying RespiratorsAir-supplying respirators are either self-contained breathing apparatus (SCBA) or hose-linerespirators. These respirators are designed to be used in oxygen-deficient atmospheres.

3.12 Personal Protective Equipment

Each human being has more than 19 square feet of surface area and breathes more than 3,000 gallons of air per day. Because chemical exposure comes through inhalation, ingestion,injection, and skin contact, protective measures have to be in place. Personal protectiveequipment (PPE) is an effective means of protecting technicians from hazardous situations.Engineering and environmental controls provide another layer of protection. The primary pur-pose of PPE is to prevent exposure to hazards when engineering or environmental controlscannot be used.

Typical outerwear worn by process technicians includes:• Safety hat• Safety glasses• Fire-retardant clothing• Safety shoes• Hearing protection• Gloves• Face shield• Chemical monogoggles• Slicker suit• Radio• Respirator• Chemical suit• Totally encapsulating chemical protective suit

3.13 Emergency Response

The chemical manufacturing industry defines an emergency as a loss of containment of a chem-ical or the potential for loss of containment that results in an emergency situation requiring an im-mediate response. Examples of emergency response situations include fires, explosions, vaporreleases, and reportable-quantity chemical spills.

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The levels of response for a first responder have been determined by the chemical processingindustry to be:

• First responder awareness level—individuals are trained to respond to a hazardoussubstance release, initiate an emergency response, evacuate the area, and notifyproper authorities

• First responder operations level—individuals are trained to respond with an aggressiveposture during a chemical release by going to the point of the release and attemptingto contain or stop it

Emergency Response PPE LevelsEmergency response uses four levels of personal protective equipment, according to theEnvironmental Protection Agency and the Occupational Safety and Health Administration.

1. Level A mandates the highest level of PPE protection by requiring a technician to don a totallyencapsulating chemical protective suit.

2. Level B deals with chemical exposures that are not considered to be extremely toxic un-less they are absorbed through the skin. In this case, a non-airtight chemical protectivesuit may be worn. Typically, the openings on a non-airtight chemical suit are taped to limitexposure.

3. Level C is used when the hazard is determined not to adversely affect exposed skin.4. Level D provides the least amount of protection to a process technician. Level D protection

is determined by individual companies, because the standard personal protective equipmentis the work uniform.

3.14 Plant Permit System

The plant permit system is a regulated system that uses a variety of permits for various appli-cations. The types of permits used in the chemical processing industry include:

• Cold work permit—routine maintenance and mechanical work• Hot work permit—any maintenance procedure that produces a spark, excessive heat,

or requires welding or burning• Opening/blinding permit—removing blinds, installing blinds, or opening vessels, lines,

and equipment• Permit to enter—designed to protect employees from oxygen deficient atmospheres,

hazardous conditions, power-driven equipment, and toxic and flammable materials• Unplugging permit—barricades area, clears lines for unplugging, informs personnel,

issues opening/blinding permit, issues unplugging permit• Energy isolation procedure—isolates potentially hazardous forms of energy, such as

electricity, pressurized gases and liquids, gravity, and spring tension• Lock-out/tag-out procedure—a standard according to which technicians shut down

a piece of equipment at the local start/stop switch, turn the main breaker off, attach alock-out adapter and process padlock, try to start the equipment, and tag it as beingout of service (tag-out) and record the incident in a lock-out logbook

3.14 Plant Permit System

81

3.15 Classification of Fires and Fire Extinguishers

The fire classification system is designed to simplify the selection of firefighting techniques andequipment.

• Class A fires involve the burning of combustible materials such as wood, paper,plastic, cloth fibers, and rubber.

• Class B fires involve combustible and flammable gases and liquids and grease.• Class C fires are categorized as electrical fires. They involve energized equipment

and class A, B, and D materials that are located near the fire.• Class D fires involve combustible metals such as aluminum, magnesium, potassium,

sodium, titanium, and zirconium.

The five types of fire extinguishers most commonly found in the chemical processing industry, andtheir range of effectiveness, are as follows:

1. Carbon dioxide (CO2) extinguishers are effective on class B and C fires because they cooland displace oxygen.

2. Dry chemical fire extinguishers are effective on class A, B, and C fires because they displaceoxygen.

3. Foam fire extinguishers are used to control flammable liquid fires.The foam forms an effectivebarrier between the flammable liquid and the oxygen needed for combustion. Foamextinguishers are effective on class A and B fires.

4. Halon fire extinguishers are designed for use on class A, B, and C fires.5. Water fire extinguishers are designed for use on class A fires only. Figure 3–5 shows some

common fire extinguishers.

3.16 HAZWOPER

The term HAZWOPER is used to describe OSHA’s hazardous waste operations and emergencyresponse standard. HAZWOPER is broken down into the following areas:

• Emergency response—first responder awareness level, first responder operationslevel

• Hazardous waste operations—incident command system, scene safety and control,spill control and containment, decontamination procedures, emergency terminationor all-clear notification

• Hazard protection, prevention, and control– terms and definitions– PPE levels– identification of hazardous materials– hazards initiating an emergency response– avoiding hazards– entry of hazardous materials into the body– unit monitors and field survey instruments

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Figure 3–5 Fire Extinguishers

3.17 Hearing Conservation and Industrial Noise

When OSHA was enacted in 1970, federal regulations for controlling noise in the workplace wereimplemented. This new standard has two major components: (1) maximum noise exposure, and (2) actions that employers must take if the limits are exceeded.Under this standard, employers must:

• Reduce noise using engineering and administrative controls.• Provide hearing protection for employees.• Implement a hearing conservation program (HCP):

– monitor sound levels– conduct audiometric tests– provide hearing protection– provide training

3.17 Hearing Conservation and Industrial Noise

83

Dry Chemical

Fuel

Heat Oxygen

Discharge Lever

Carrying Handle

Discharge Horn

Carbon Dioxide

Pick-up Tube

Pin

Discharge Lever

Carrying Handle

Nozzle

Discharge Lever

Dry Chemical

Cap

Handle

PuncturingLever

CO2

Pick-up Tube

3.18 Department of Transportation

Shipments of hazardous materials are regulated by the U.S. Department of Transportation (DOT)(Figure 3–6). The DOT regulations contain specific information on how hazardous materials are tobe identified, placarded, documented, labeled, marked, and packaged. Hazardous material ship-ments that are not in compliance with federal regulations will be delayed, and noncompliance canresult in severe penalties. In civil cases, marking the wrong name on a container can incur fines ofup to $25,000 per violation. In criminal cases, fines of up to $500,000 and five years in jail can beimposed for intentionally shipping a hazardous chemical and attaching the wrong MSDS.

Materials are classified for transportation using nine different categories:1. Explosive 6. Poisonous and Infectious Materials2. Gases 7. Radioactive Materials3. Flammable Liquids 8. Corrosive Materials4. Self Reactive 9. Miscellaneous Hazardous Materials5. Oxides and Peroxides

Summary

Safety, health, and environment training includes initial and continuous training and the employ-ment of safety systems that are carefully integrated into everyday operation. Some of thesesystems include permits, personal protective equipment, firefighting, hazard communication,HAZWOPER, and process safety management.

OSHA and the EPA developed the process safety management (PSM) standard to prevent the cat-astrophic release of toxic, hazardous, or flammable materials that could lead to a fire, explosion,or asphyxiation. Several critical elements of the PSM standard include employee training, opera-tions procedures, process safety, employee participation, and hot work.

A fundamental principle of the chemical hazard communication (HAZCOM) program is that in-formed people are less likely to be injured by chemicals and chemical processes than uninformedpeople. A chemical hazard communication program is composed of both information and training.

Chemical exposure comes from inhalation, ingestion, injection, and/or absorption (skin contact).Personal protective equipment provides an effective means for protecting technicians from haz-ardous situations. Engineering and environmental controls provide another layer of protection.Theprimary purpose of PPE is to prevent exposure to hazards when engineering or environmentalcontrols cannot be used. Process technicians use two basic types of respirators: air purifying andair supplying. Hearing conservation regulations have two major components: maximum noiseexposure and actions employers must take if the limits are exceeded.

The types of permits used in the chemical processing industry include cold work permits, hot workpermits, opening/blinding permits, permits to enter, unplugging permits, energy isolation proce-dures, and lock-out, tag-out procedures.

Fires are classified as Class A, B, C, or D. The most common fire extinguishers found in industryare CO2, dry chemical, foam, halon, and water fire extinguishers.

84


The term HAZWOPER describes OSHA’s hazardous waste operations and emergency responsestandard. HAZWOPER covers the areas of emergency response; hazardous waste operations;and hazard protection, prevention, and control.

Shipments of hazardous materials are regulated by the U.S. Department of Transportation. DOTregulations contain specific information on how hazardous materials are identified, placarded,documented, labeled, marked, and packaged.

Summary

85

3

FLAMMABLEGAS

22

NON-FLAMMABLEGAS

OXYGEN

2

5

OXIDIZER

5

ORGANICPEROXIDE

COMBUSTIBLE

3

FLAMMABLE

POISONGAS

2

POISON

8

CORROSIVE

6

43 2

W

NFPA DIAMOND

HEALTHHAZARD

FIREHAZARD

REACTIVITYHAZARD

SPECIFICHAZARD

PLACARDS

SHIPPER'S DECLARATION FOR DANGEROUS GOODS

Shipper

Consignee

Bigg Chemical Co.4500 Baker DriveBaytown, TX 77520

Mr. John Doe1987 MacbethSalt Lake City, UT 84501

Air Waybill No.

Page 1 of 1

Transport Details

Passenger

and Cargo

Cargo

Aircraft only

Airport of Destination

WARNING

Failure to Comply in all respects with theapplicable Dangerous goods Regulationsmay be a breach of the applicable law, subject to legal penalties.

Shipment TypeNON-RADIOACTIVE RADIOACTIVE

PROPER SHIPPING NAME

CLASS ID Sub-Risk

QUANTITYTYPE OF PACKING

PACKINGINSTRUCT

AUTHORIZATION

ADDITIONAL HANDLING INFORMATION

I hereby declare that the contents of the consignment are fullyand accurately described above by proper shipping name andare classified, packed, marked and labelled, and are in all respects in the proper condition for transport by air according to the National Regulations.

Name/ Title

Place & Date

Signature

Chemical Name

HEALTH

FLAMMABILITY

REACTIVITY

PERSONAL PROTECTION

2

0

1

E

HMIS SYSTEM

SHIPPING PAPERS

1. Material Classification2. Shipping Papers3. Labeling 4. Placarding5. Emergency Response

THE DOT SYSTEM

Figure 3–6 DOT Labels, Signs, and Placards

86


Chapter 3 Review Questions1. Describe the basic principles of process safety management.

2. Describe the important features of the HAZCOM program.

3. Describe the important features of HAZWOPER.

4. What personal protective equipment does a process technician typically wear?

5. What is the respiratory protection standard?

6. What three agencies are primarily responsible for administration of the OccupationalSafety and Health Act?

7. What is the Occupational Safety and Health Administration?

8. Describe the major features of the PSM standard and explain its importance.

9. What is emergency response?

10. What is toxicology, and how are dose and response important?

11. Describe the role of the DOT in ensuring the safety of hazardous materials.

12. What is a physical hazard?

13. Identify the physical properties of and hazards associated with handling, storing, andtransporting chemicals.

14. What is a fundamental principle of the chemical hazard communication program?

15. What are the two basic types of air-purifying respirators?

16. What are the basic types of air respirators?

17. Describe the key elements of the permit system.

18. What do you think are the 10 most important general safety rules for a chemical plant?

19. What are the critical elements of hearing conservation, including the employer’sresponsibilities?

20. What do you think is the most important safety rule?

Applied Physics OneAfter studying this chapter, the student will be able to:

• Describe key terms and definitions used in basic process principles.• Describe and apply the basic principles of pressure.• Perform pressure calculations.• Analyze the scientific principles of heat, heat transfer, and temperature.• Perform simple temperature conversions between the Fahrenheit, Celsius,

Kelvin, and Rankine scales.• Examine and apply the principles of fluid flow in process equipment.• Solve basic mathematical problems encountered in industry.

87

88

Chapter 4 ● Applied Physics One

Key TermsAbsorbed heat—transferred heat; effects include increase in volume and temperature, changeof state, electrical transfer, and chemical change.

Algebra—a branch of mathematics that uses letters to represent numbers and signs to repre-sent operations. It is a kind of universal arithmetic or, more simply, mathematics using letters.

Bernoulli’s principle—states that in a closed process with a constant flow rate, changes influid velocity (kinetic energy) decrease or increase pressure; kinetic-energy and pressure-energychanges correspond to pipe-size changes; pipe-diameter changes cause velocity changes; andpressure-energy, kinetic-energy (fluid velocity), and pipe-diameter changes are related.

Boyle’s law—at a constant temperature, the volume of a gas is inversely proportional to itspressure.

V1 P2 or P1 V1 � P2 V2V2

�P1

Charles’s law—at a constant pressure, the volume of a gas is proportional to its absolutetemperature.

V1 T1 or V1 �V2

V2�

T2 T1

___

T2

___

Dalton’s law—states that the total pressure of a gas mixture is the sum of the pressures of theindividual gases:

Ptotal � P1 � P2 � P3

Fluid flow—flow characterized by fluid particle movements (e.g., laminar or turbulent).

Heat—a form of energy caused by increased molecular activity.

Heat transfer—transmission of heat through conduction (heat energy transferred through asolid object; e.g., a heat exchanger), convection (heat transferred by fluid currents from a heatsource; e.g., the convection section of a furnace or the economizer section of a boiler), or radi-ation (heat energy transferred through space by means of electromagnetic waves; e.g., the sun).

Ideal gas law—combination of Boyle’s and Charles’s laws, expressed as:

P1V1 P2V2

T1 �

T2

Liquid pressure—the pressure exerted by a confined fluid. Liquid pressure is exerted equallyand perpendicularly to all surfaces confining the fluid.

Mathematics—field dealing with numbers and number operations. Process technicians use avariety of mathematical and scientific functions to perform their jobs. Some of the terms usedin this area include:

• addition—a term applied to a mathematical operation for combining numbers.• conversion tables—charts that display equivalent units of measure.

• decimal point—the period or “dot” between whole numbers and fractional numbers.• denominator—the bottom number in a fraction.• dimensional analysis—conversion within one system of units or to another system of

units. Example: changing English-system feet to International System (SI) meters.• division—a mathematical operation for determining how many times one number

or quantity is contained in another number or quantity.• divisor—the number by which one is dividing.• fraction—a part of a whole amount.• grouping symbols—signs used to separate functions in an equation.• lowest common denominator (LCD)—the smallest whole number that can be used

to divide two or more denominators.• mixed number—a whole number and a fraction.• multiplication—the process of adding a number to itself a specified number of times.• numerator—the top number in a fraction.• percent—a fractional amount expressed in terms of parts per one hundred.• subtraction—a mathematical operation in which one number is deducted from another.

Pascal’s law—pressure in a fluid is transmitted equally in all directions, molecules in liquidsmove freely, and molecules are close together in a liquid.

Pressure—force or weight per unit area (Force � Area � Pressure); measured in pounds persquare inch.

Temperature—the hotness or coldness of a substance.

4.1 Basic Principles of Pressure

Pressure is defined as force or weight per unit area (Force � Area � Pressure). The term pres-sure is typically applied to gases or liquids. Pressure is measured in pounds per square inch (psi).Atmospheric pressure is produced by the weight of the atmosphere as it presses down on an ob-ject resting on the surface of the earth. “The earth is surrounded by a fluid consisting of 78%nitrogen and 21% oxygen. Pressure at the top of this fluid, “air” is measured at zero psia and14.7 psia (1.3 kPa) at sea level. Figure 4–1 illustrates this point. The higher the atmosphere, orgas, or liquid, the greater the pressure at the bottom.

In a liquid, pressure is not dependent upon the shape or size of the vessel or pipe. Figure 4–2 illus-trates this point. Pressure is equal to the force divided by the area. A simple equation can be usedto calculate pressure in a process system.Height � .433 � specific gravity � pressure.Any additionalpressure or force above the liquid must be added to the answer. Vapor pressure, nitrogen blankets,or control pressures are examples of variables that should be added into the total pressure.

The factor of .433 was developed using the equation P � F � A. Figure 4–3 illustrates how thisfactor was developed. Specific gravity for a substance is also calculated using the water standard.For example: 1 gallon of water weighs approximately 8.33 pounds. 8.33 � 8.33 � 1. The spe-cific gravity of water is 1. Other substances have different weights. For example, if 1 gallon of asubstance weighs 6.5 pounds, it’s specific gravity can be calculated by dividing 6.5 pounds by8.33 pounds � .78. The specific gravity of this new substance is .78. Using this simple approachthe specific gravity of any substances can be calculated.

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Figure 4–4 illustrates how a simple pressure calculation is performed by a technician.

Two of the most common types of pressure are atmospheric and hydrostatic. Atmospheric pres-sure is the force exerted on the earth by the weight of gases that surround it. Pressure decreaseswith altitude because of the reduced height (weight) of the gas.

Hydrostatic pressure is the pressure exerted on a contained liquid and is determined by thedepth of the liquid. Even a novice swimmer is familiar with pressure differences between the sur-face of the water and bottom of the pool. This pressure difference is what causes your ears topop as you drive over a mountain in Colorado (atmospheric) or swim to the bottom of a 10’ pool(hydrostatic).

Boiling Point and Vapor PressureThe boiling point of a substance is the temperature at which the vapor pressure exceeds atmos-pheric pressure, bubbles become visible in the liquid, and vaporization begins.

90


Vacuum of Space

14.7 psi

0 psi

Oxygen

Nitrogen

Atmosphere

Atmospheric Pressure

21%

78%

Figure 4–1 Atmospheric Pressure

Liquid Level

Pi PiPiPiPi Pi

Figure 4–2 Shape vs. Pressure

Molecular motion in water vapor produces pressure; both motion and pressure increase as heatis added to the liquid. The vapor pressure of a substance is directly linked to the strength of themolecular bonds of a substance. The stronger the bonds or molecular attraction, the lower the va-por pressure. If a substance has a low vapor pressure, it will have a high boiling point. For exam-ple, gold changes from a solid to a liquid at 1,947°F (1,064°C) and boils when the temperaturereaches 5,084°F (2,807°C). Water changes from a solid to a liquid at 32°F (0°C ) and boils whenthe temperature reaches 212°F (100°C).

Liquids need not reach their boiling points to begin the process of evaporation. For example, a panof water placed outside on a hot summer day (98°F [36.66°C]) will evaporate over time. The sunincreases the molecular activity of the water vapor, and some of the molecules escape into theatmosphere.Wind currents enhance the process of evaporation by sweeping away water moleculesin vapor that are replaced by other water molecules.

Pressure Impact on BoilingPressure directly affects the boiling point of a substance. As the pressure increases:

• The boiling point increases• The escape of molecules from the surface of the liquid is reduced• The gas or vapor molecules are forced closer together• The vapor phase above a liquid could be forced back into solution


91

1 cubic foot of water

Area 12" X 12" = 144"

P = 62.4 lbs.

P = .433.

P = F ÷ A

144

(Force) Weight = 62.4 lbs

12"

12"

Figure 4–3 Pressure Equation

These are important facts for a process technician to understand. A change in pressure shifts theboiling points of raw materials and products. Pressure problems are common in industrial manu-facturing environments and must be controlled.

VacuumAtmospheric pressure is 14.7 psi. Any pressure below this is referred to as a vacuum, even if thepressure is not completely absent (zero). Vacuum affects the boiling point of a substance in theopposite way that positive pressure does.

92


PIC

Flare

FIC

I P

FT

FE

FC

FT

FIC

Specific Gravity .69

Pi

I P

12 psi

height X .433 x specific gravity =

45’ X .433 x .69 = 13.4 psi + 12 psi = 25.4 psi

PT

PE

30’-0”

30’-0”

15’-0”

0

0 0

0 0

0 0

0

0 0 0 0

0 0

0 0 0

0

Pi

I P

Pump

Figure 4–4 Simple Pressure Calculation

Vacuum systems:

• Lower the boiling point of a substance• Enhance the molecular escape of a liquid• Reduce energy costs• Reduce molecular damage due to overheating• Reduce equipment damage

Pascal’s LawBlaise Pascal was a French scientist who discovered that pressure in a fluid is transmitted equallyin all directions. Pascal successfully described the effects of pressure in a liquid and establishedthe scientific foundation for hydraulics. Key facts for process technicians to remember in regard toPascal’s law are that pressure in a fluid is transmitted equally in all directions, molecules in liq-uids move freely, and molecules are close together in a liquid.

Boyle’s LawRobert Boyle was an Irish scientist who developed the law that describes how the volume of a gasresponds to pressure changes. Key facts for process technicians to remember in regard to Boyle’slaw are that pressure decreases volume and moves gas molecules closer together; the higher thepressure, the smaller the volume; and gas volume decreases by one-half when pressure doubles.Boyle’s law can be written as: P1V1 � P2V2.

Determining Pressures Produced by LiquidsThe pressure a liquid exerts on a container is determined by the height (amount) and density ofthe fluid.The pressure exerted by a 20-foot (ft) column of mercury would be more than that exertedby a 20-foot column of water, because the specific gravity of mercury (Hg) is much higher than thatof water.

Pressure ProblemsPressure problems can be correctly calculated by using the following formula:

Pressure � Force � Area

EXAMPLE 1: StoneCalculate the pressure produced by a 1,000-pound (lb.) stone block (see Figure 4–5) that is20 inches long and 20 inches wide.


93

1,000 lb

20 in.

20 in.

20 in.

Figure 4–5 Stone Block

Solution: The area occupied by the stone � 400 sq in.20-in. length � 20-in. width � 400 sq in.Pressure � 1,000 � 400 � 2.5 psiThe psi at the base of the stone � 2.5 psi

EXAMPLE 2: WaterCalculate the pressure produced by one cubic foot of water (62.4 lb) in a vessel that is 1 foot high,1 foot long, and 1 foot wide.

Solution: 1-ft length � 1-ft width � 1-ft height � 1 sq ft or 144 sq in.1-ft3 H2O � 62.4 lb H2OPressure � 62.4 � 144 � 0.433 psi

Note: Each additional foot of water will add 0.433 psi. A common formula used to figure pressure is:

Height � 0.433 � Specific Gravity � Pressure

EXAMPLE 3: GasolineCalculate the pressure produced by 1 cubic foot of gasoline (0.75 specific gravity [sg]) in a vesselthat is 1 foot long, 1 foot high, and 1 foot wide.

Solution: 1-ft length � 1-ft width � 1-ft height � 1 sq ft or 144 sq in.� 62.4 lb H2O � 0.75 sg

Pressure � 47 � 144 � 0.327 psi

Note: Each additional foot of gasoline will add 0.327 psi.

EXAMPLE 4: WaterCalculate the pressure produced by water (62.4 lb) in a 6-ft high vessel.

Solution: 1 sq ft or 144 sq in. � 62.4 lb H2O62.4 lb � 6 ft � 144 sq in. � 2.6 psi

Now try: Height � 0.433 � Specific Gravity � Pressure6 ft � 0.433 � 1 � 2.6 psi

EXAMPLE 5: WaterCalculate the pressure produced by water (62.4 lb) in a 200-ft-high vessel.

Solution: 200 ft � 0.433 � 1 � 86.6 psi

EXAMPLE 6: GasolineCalculate the pressure exerted on the bottom of a 20-ft distillation column filled with gasoline.Add 100 psi to the column, giving a top gauge reading of 100 psi. What will be the bottom gaugereading in psi?

Solution: To calculate the bottom pressure of the distillation column, two variables must beconsidered:The pressure of the gasoline � 20 ft � 0.433 � 0.75 � 6.5 psiPlus the pressure added to the column: 100 psi.

The answer is 6.5 psi � 100 psi � 106.5 psi.94


EXAMPLE 7: GasolineCalculate the pressure exerted on a 20-ft column filled with 10 ft of gasoline. The vapor pressureof gasoline at 100°F is 12 psi.

Solution: 10 ft � 0.433 � 0.75 � 3.25 psi3.25 � 12 psi � 15.25 psi

The answer is 15.25 psi.

Principles of Liquid PressureThe principles of liquid pressure are (see Figures 4–6 and 4–7):

1. Liquid pressure is directly proportional to the density of the liquid.2. Liquid pressure is proportional to the height (amount) of the liquid.3. Liquid pressure is exerted in a perpendicular direction on the walls of a vessel.4. Liquid pressure is exerted equally in all directions.5. Liquid pressure at the base of a tank is not affected by the size or shape of the tank.6. Liquid pressure transmits applied force equally, without loss, inside an enclosed

container.

Absolute, Vacuum, and Gauge PressureThree different types of pressure gauges can be found in industrial environments: absolute (psia),gauge (psig), and vacuum (psiv) (see Figure 4–8). Absolute pressure is equal to gauge pressureplus local atmospheric pressure (at sea level, 14.7 psi). Gauge pressure is equal to the absolutepressure minus the local atmospheric pressure (at sea level, 14.7 psi). Vacuum is measured typ-ically in inches of mercury (in. Hg). Any pressure below atmospheric pressure (14.7 psi) is referredto as vacuum.

Gases and PressureLiquids typically are considered to be noncompressible even though a 10% decrease in volumecan be observed when a pressure of 65,000 psi is applied. Gases behave much differently thanliquids. Gases are very compressible. The volume of a gas is determined by the shape of the


95

WATER MERCURY GASOLINE

Density840.7 lb

cu ft

Density62.4 lbcu ft

Density47 lbcu ft

5.9 psi0.433 psi per ft 0.327 psi

1.299

2.17

3.03

3.959 psi 3.27 psi

1.64 psi29.5 psi

121110987654321

121110987654321

121110987654321

4.33

3.46

2.6

1.732

0.866

PRESSURE

Figure 4–6 Liquid Pressure Principles 1, 2, 3

vessel containing it, the temperature, and the pressure. Operators use these three factors in thecontrol and storage of gases.

Gas LawsDalton’s law (Ptotal � P1 � P2 � P3) states that the total pressure of a gas mixture is the sum of thepressures of the individual gases. In the distillation process, Dalton’s law can be applied by a processtechnician to each individual tray in a plate column system. Distillation is a process that separatesthe components in a mixture by their individual volatilities or boiling points. The larger the differencebetween the partial pressures, the easier it is to separate the fractions by boiling point. Each tray ina distillation column has a different molecular structure and the vapors above the liquid will be com-posed of the vaporized fractions moving up the column. Lighter components will exert a higher pres-sure. According to Dalton’s law, each tray will have a different pressure. These pressures can be

96


WATER13 psi

WATER13 psi

WATER13 psi

Pressureexertedequally

in alldirections

Appliedforce

transmittedequally

without loss

30 ft 30 ft 30 ft

WATER

30 ft

Figure 4–7 Liquid Pressure Principles 4, 5, 6

05

101520

PSIG

GAUGE

05

101520

PSIA

ABSOLUTE

30

150

10

30PSIV

VACUUMPSIG = PSIA - 14.7 PSIA = PSIG + 14.7

Figure 4–8 PSIA–PSIG–PSIV

calculated if we know the original feedstock composition and the vapor pressures of the individualcomponents at a set temperature. For example, a feedstock containing 25% hexane, 50% benzene,and 25% heptane will exert partial pressures at different temperatures that can be added up to givethe total pressure. The equation (Ptotal � P1 � P2 � P3) can be used to identify what the total pres-sure is on tray #6 in Figure 4–9. One of the primary components in the mixture, benzene, is repre-sented in Figure 4–10. Benzene is the most common aromatic hydrocarbon. It has six carbon atomsconnected in a ring; each carbon atom has four carbon bonds, three used and one free.

Substance Vapor Pressure @ 175°F in PSIA

Hexane 20.6 PSIA � .25 � 5.15 PSIA

Benzene 14.7 PSIA � .50 � 7.35 PSIA

Heptane 8.8 PSIA � .25 � 2.2 PSIA

14.7 PSIA (Ptotal) � 5.15 (P1) � 7.35 (P2) � 2.2 (P3)

Original BP

Hexane C6H14 5.15 � 14.7 � .35 � 100 � 35% 25% 69°C

Benzene C6H6 7.35 � 14.7 � .5 � 100 � 50% 50% ?

Heptane C7H16 2.2 � 14.7 � .15 � 100 � 15% 15% 98°C


97

FE FT

TE

TE

TT

I P

FIC

TIC

ºF

ºF SP PV OP% %

DPT

Dalton’s Law Partial Pressures

TE

TE

TE

Feed Tray #7

Tray #6

Tray #8

Tray #9

175ºF Feed Mix

P total

P total

= 7.35 + 5.15 + 2.2

= 14.7 psia

Benzene 50% 14.7 psia @ 175ºF Hexane 25% 20.6 psia @ 175ºF Heptane 25% 8.8 psia @ 175ºF

Vapor Pressure @ 175ºF Benzene 50% 14.7 X .05 = 7.35 psia Hexane 25% 20.6 psia X .25 = 5.15 psiaF Heptane 25% 8.8 psia X .25 = 2.2 psia

Benzene 50% Hexane 35% Heptane 15%

Tray #10

FT

I P

FIC

FO

Figure 4–9 Dalton’s Law of Partial Pressures

Charles’s law states that a constant pressure, the volume of a gas is proportional to its absolutetemperature. (At a constant pressure the volume will increase as the temperature increases, or de-crease as the temperature decreases.)

V1 T1 or V1 � V2

V2�

T2 T1

___

T2

___

Charles’s law and Boyle’s law can be combined into a single formula called the ideal gas law(PV � nRT), which calculates the pressure, temperature, volume, or moles of any gas.

P � pressure of the gasV � volumen � moles of gasT � temperature in Kelvins (K)R � ideal gas constant (0.08206 L � atm/mol � K)

The combined gas law calculates changes in a gaseous substance from one condition to anotherand is expressed as:

P1V1 P2V2

T1�

T2

As an example of Charles’s law, let us start by blowing up a balloon to a volume of 1 liter at 28°Cand then cool the balloon to 10°C. What is the volume of the balloon when the gas cools? Theproblem can be solved using the same kind of ratio used with Boyle’s law. Since V1 � k � T1 andV2 � k � T2, the relationship is expressed as:

V2 T2

V1�

T1

98


H

H

C

C

C

C C

C

H

H

H

H

H

H

H

H H

H

Benzene- a total of six electrons can be found in the donut-shaped clouds.

Figure 4–10 True Benzene Ring

T1 is calculated by converting 28°C to K. 28°C � 273 � 301K. T2 is 10°C � 273 � 283K.

V2 283K

1L �

301K

V2 � 1L � 283/301 � .94L � 940mL

According to Charles’s law and the kinetic molecular theory of gases, a gas held at a steady pres-sure will increase in volume as the temperature increases or will decrease in volume as thetemperature decreases.

4.2 Heat, Heat Transfer, and Temperature

Heat is a form of energy caused by increased molecular activity. A basic principle of heat statesthat it cannot be created or destroyed, only transferred from one substance to another. Heat movesfrom warmer areas to colder areas, transferring energy as it goes.This process continues until theheat energy has been equally distributed. A stone thrown into a still pool of water sends ripplesout in all directions; heat energy moves in a similar pattern.

Heat is measured in energy units called British thermal units (Btus). A Btu is the amount of heatneeded to raise one pound of water one degree Fahrenheit. Another common unit used in indus-trial manufacturing is the calorie. One calorie is roughly equal to the heat energy required to raisethe temperature of one gram of water one degree Celsius.

The effects of absorbed heat are:• Increase in volume• Increase in temperature• Change of state (solid, liquid, gas)• Chemical change (matches)• Electrical transfer (thermocouple)

Heat comes in a variety of forms:• Sensible heat—heat that can be sensed or measured; increase or decrease in

temperature• Latent heat—hidden heat that does not cause a temperature change• Latent heat of fusion—heat required to melt a substance; heat removed to freeze a

substance• Latent heat of vaporization—heat required to change a liquid to gas• Latent heat of condensation—heat removed to condense a gas• Specific heat—the Btus required to raise one pound of a specific substance by 1°F.

Heat transfer occurs in different ways. Heat is transmitted through:

• Conduction—occurs when heat energy is transferred through a solid object (e.g., a boiler)• Convection—occurs when fluid currents transfer heat from a heat source (e.g., upper

convection section of a furnace)• Radiation—occurs when heat energy is transferred through space by means of elec-

tromagnetic waves (e.g., the sun)

4.2 Heat, Heat Transfer, and Temperature

99

TemperatureBy measuring the hotness or coldness of a substance, we determine temperature. Process op-erators use a variety of temperature scales (see Figure 4–11). The four most common systemsare described here:

Scale Water Boils Water Freezes Conversion Formula

Kelvin (K) 373 K 273 K K � °C � 273

Celsius (°C) 100°C 0°C °C � (°F � 32) � 1.8

Fahrenheit (°F) 212°F 32°F °F � 1.8°C � 32

Rankine (°R) 672°R 492°R °R � °F � 460

Key Points to Remember• Heat is a form of energy caused by increased molecular activity; it cannot be created

or destroyed, only transferred from one substance to another.• The hotness or coldness of a substance determines the temperature.• Heat is measured in Btus; temperature is measured by one of the temperature scales

(e.g., K, C, F, or R).• Temperature and heat are not the same.

4.3 Fluid Flow

Modern industrial process plants are connected by a complex network of pipes, valves, pumps,and tanks. Centrifugal and positive displacement pumps are used to transfer fluids from place to

100


˚F ˚R ˚C K 212 100 373 K 672˚R

Water boils

Water freezes

32 492˚R 0 273 K

-460 0˚R -273 0 K

Fahrenheit = F Rankine = R Celsius = C Kelvin = K

ABSOLUTE ZERO

˚C

˚C

˚C

˚F

˚F

˚F

Figure 4–11 Temperature Scales

place inside and outside the plant.The combination of pumps and pipes closely resembles the waythe human heart pumps fluid into arteries and veins.

Fluids assume the shape of the container they occupy. A fluid can be a liquid or a gas. When aliquid is in motion, it remains in motion until it reaches its own level or is stopped. Fluid flow is acritical concept used in the day-to-day operation of all plants.

Flow rate � Volume � Time

Example:

FR � 6.0 gallons � 2.5 minutesFR � 2.4 gpm

Bernoulli’s PrincipleThe Swiss scientist Daniel Bernoulli developed a key scientific principle for fluid flow.Bernoulli’s principle states that in a closed process with a constant flow rate, changes in fluidvelocity (kinetic energy) decrease or increase pressure; kinetic-energy and pressure-energychanges correspond to pipe-size changes; pipe-diameter changes cause velocity changes;and pressure-energy, kinetic-energy (or “fluid velocity”), and pipe-diameter changes arerelated.

Reynolds Number �(Velocity of Fluid) (Inside Diameter of Pipe) (Density of Fluid)

(Absolute Viscosity of Fluid)

ViscosityAnother term commonly used in industry to describe the flow characteristics of a substance isviscosity (see Figure 4–12). Viscosity is defined as a fluid’s resistance to flow.

DensityIndustry uses four different ways to express a fluid’s heaviness: density, specific gravity, baumegravity, and API gravity.

4.3 Fluid Flow

101

Water Lube Oil

Figure 4–12 Viscosity

The density of a fluid is defined as the mass of a substance per unit volume. Density measure-ments are used to determine heaviness. For example, one gallon of water weighs 8.33 lb, one gal-lon of crude oil weighs 7.20 lb, and one gallon of gasoline weighs 6.15 lb.

Specific GravitySpecific gravity (sg) is defined as the ratio of a fluid’s density (liquid or gas) to the densityof water or air. It is common for operators to confuse specific gravity with density. This mis-take is easy to understand, because specific gravity is a method for determining the heavinessof a fluid. Density is the heaviness of a substance. Specific gravity compares this heavinessto a standard and then calculates a new ratio. Most hydrocarbons have a specific gravitybelow 1.0.

Key Points to Remember• Density is calculated by weighing unit volumes of a fluid at 60°F (15.55°C).• The density of one gallon of water is 8.33 lb/gal.• The density of air is 0.08 lb/cu ft.• The specific gravity of water is 8.33 lb/gal � 8.33 � 1.0.• The specific gravity of gasoline is 6.15 lb/gal � 8.33 � 0.738.

Baume GravityBaume gravity is the standard used by industrial manufacturers to measure nonhydrocarbonheaviness.

API GravityThe American Petroleum Institute (API) applies gravity standards to measure the heaviness of ahydrocarbon. A specially designed hydrometer, marked in units API, is used to determine theheaviness or density of a hydrocarbon. High API readings indicate low fluid gravity.

Turbulent and Laminar FlowTwo major classifications of fluid flow are laminar and turbulent (see Figure 4–13). Laminar flow,or streamline flow, moves through a system in thin cylindrical sheets of liquid flowing inside oneanother. This type of flow has little, if any, turbulence in it. Laminar flow usually exists at lower flowrates. As flows increase, the laminar flow pattern breaks into turbulent flow. Turbulent flow is therandom movement or mixing of fluids. Once turbulent flow is initiated, molecular activity speeds upuntil the fluid is uniformly turbulent.

Turbulent flow allows molecules of fluid to mix more readily and absorb heat. Laminar flow pro-motes the development of static film, which acts as an insulator.Turbulent flow decreases the thick-ness of static film.

Forms of Liquid EnergyLiquid energy may take the form of kinetic energy (fluid motion), pressure and potential energy(stored energy, liquid head, internal pressure), or heat energy (fluid friction).

102


Fluid Energy Conversions• Steam turbine—steam-pressure energy is converted to kinetic energy; kinetic energy

is converted to rotational or mechanical energy.• Boiler—heat energy is transferred to water; water boils, creating steam energy. Steam

energy creates pressure energy. Steam and pressure energy are used in distillation,heat exchangers, reactors, laminating, extrusion, and steam turbines.

• Furnace—heat energy is transferred to the charge.• Distillation tower—heat energy is transferred to a feed, which separates the individual

components by boiling point. Condensation and vaporization occur along the temper-ature gradient of the tower.

• Energy is converted into kinetic energy. As fluid slows, it is converted into pressureenergy.

Measuring Flow RateFlow rate (in gallons per minute or gpm) equals volume per unit of time.Velocity (in feet per secondor fps, feet per minute or fpm, feet per hour or fph) equals distance per unit of time.

Flow of SolidsA variety of gases are used to transfer solids from one location to another: nitrogen, air, chlorine,and hydrogen. When properly fluidized, solids respond like fluids. Solid transfer requires small,granular, porous solids that respond positively to aeration. Several examples of industry processesthat use this procedure are modern plastics manufacturing (granules, powder, flakes), catalyticcracking units, and vacuum systems.

4.3 Fluid Flow

103

Static flow

Turbulent flow

Restrictions and bendscreate turbulence

Laminar flow

Laminar flow

Figure 4–13 Laminar and turbulent flow

4.4 Basic Math for Process Technicians

Basic mathematics is typically encountered on the preemployment tests administered by mostplants. Inability to handle simple mathematics functions appears to be the primary disqualifier forpotential applicants. The widespread use of calculators and the years elapsed since eighth-grademathematics require most people to review these rusty skills or risk being eliminated from the poolof applicants being invited to interview.

Process technicians use a variety of mathematical and scientific functions to perform their normaljob responsibilities. Some of these functions include:

Phase 1: Preemployment Skills Required• Addition• Subtraction• Multiplication• Division• Fractions (addition, subtraction, multiplication, and division)• Decimals (addition, subtraction, multiplication, and division)• Percents and percentages• Averaging• Mechanical aptitude• Equations (algebraic expressions)• Canceling• Ratios• Proportions (direct and inverse)• Constants and variables• Factors and factoring• Exponents• Grouping

Phase 2: On-the-Job Skills Required• Area• Volume• Volumetric flow rate• X-Y graphs• Bar graphs• Pie graphs• Strip charts• Trends• Word problems• Pressure in fluids:

– Force � Area � Height � Density– Pressure � Force � Area– Pressure � Height � Density

• Specific weight of liquid:– Weight of liquid � Weight of water

• Work, force, and distance:– W � Force � Density

104


• Mechanical advantage:– MA � Resistance � Effort

• Levers• Boyle’s law:

– P1V1 � P2V2

• Motion of bodies:– v � s � t– s � vt

• Heat transfer

Phase 1: Preemployment SkillsMathematics is an important part of operating a process unit. Flow rates must be calculated, fill-ing ratios checked, conversion tables used, additive recipes blended, and special equations ap-plied to industrial processes. The following is a review of some basic mathematical skills andoperations.

1. 1,545� 2,000

3,545

2. 1,245� 456

789

3. 8,768 � 234 � 37.47

4. Calculate the mean average of the following numbers:125,678

2,345234

1,429

STEP 1125,678

2,345234

� 1,429129,686

STEP 2129,686 � 4 � 32,421.5

5. 467,897 � 34 � 15,908,498

6. 0.4568 � 9,457 � 4,319.96

7. Convert 39 to a mixed number.19

Divide 39 by 19; the answer is 2 1 .19


105

8. Convert 1 4 to a fraction.81 � 8 � 4 � the numerator12 � the numeratorPut 12 over eight. The answer is 12.

8

9. 4 � 97 8

STEP 1When adding or subtracting fractions, first find the lowest common denominator (LCD).Find a number that both 7 and 8 can divide into:7 � 8 � 56

STEP 2 STEP 3 STEP 4Write equivalent Add the numerators. Convert to a mixed number.fractions with a common denominator.4 � 32 9 � 63 32 � 63 � 63 95 � 1397 56 8 56 56 56 56 56 56

10. 9 � 92 4

STEP 1When dividing fractions, invert the divisor.9 inverted is 4.4 9

STEP 2Multiply.9 � 4 � 36 � 22 6 18

STEP 3Convert to a whole number.36 � 218

11. 18 � 32 � 612 � 51 � 25 112 2 24 2 2

12. 4 � 33 9

STEP 1 STEP 2Write equivalent Subtract the numeratorsfractions with a and convert.common denominator.

4�

12 12�

3�

93 9 9 9 9

106


3�

3 9� 19 9 9

13. 123.678 � 0.0043 � 123.68

14. 454.67 � 12.34 � 36.85

15. A tank has a 1,400-lb mixture of water and salt in it. Of the mixture, 18% is salt. How manypounds of salt are in it?

1,400 � 0.18 � 252 lb of salt

16. Product Tank 1403 has a total capacity of 400,000 gal. At 1:00 AM, Tank 1403 has 60,000 galin it.Your product pump is filling the tank at 2.2 gal/minute. How many hours (h) do you havebefore the tank runs over?

STEP 1 STEP 2 STEP 3400,000 2.2 340,000 � 132 � 2,575.75 h

17. (102)2 � (10 � 10 � 100)2, 100 � 100 � 10,000

18. Convert 0.45 to a percentage. The answer is 45%.

19. Convert 115% to a decimal. The answer is 1.15.

Algebra is used to solve many simple problems encountered by process technicians. Basic math-ematics is useful but inadequate for all process problems. Algebra uses letters and symbols to rep-resent variables that are known and unknown.This form of mathematics allows unknown variablesto be identified by following well-defined principles.

Principle 1. An algebraic equation is structured like a balance scale.The products on the left equalthe products on the right. For example:

6x � 30 or 6 (?) � 30Solution: x � 5

Principle 2. When solving for unknowns, the opposite function must be used. Addition and sub-traction are opposites, and multiplication and division are opposites.Solve for x:

x � 5 � 2x � 5 � 5 � 2 � 5 (the opposite of addition is subtraction)

x � �3

The following are some practice problems for you to work through.

20. Solve for x:4x � 204x � 204 4x � 5


107

21. Solve for x:x � 10 � 14 � 3

x � 10 � 10 � 11 � 10x � 21

22. Solve for x:2x � 8 � x

2x � x � 8 � x � xx � 8

23. Solve for x:x � 2 � 8

x � 2 � 2 � 8 � 2x � 10

24. Solve for x:x � 14 � 16

x � 14 � 14 � 16 � 14x � 2

25. Solve for x:3 � 6 (2 � x) � 453 � 12 � 6x � 45

15 � 6x � 4515 � 15 � 6x � 45 � 15

6x � 306x � 306 6x � 5

Phase 2: On-the-Job SkillsA process technician has to deal with many volume issues on the job.The formulas in Figure 4–14are used extensively in the CPI.

108


Volume = LWH

RadiusHeight

Width

Length

Height

Volume = πr 2h

Radius

Volume = πr 343

Figure 4–14 Volume Formulas

26. A rectangular tank is 30 ft long, 16 ft tall, and 6 ft wide. What is the volume of this tank?

V � LWH30 � 16 � 6 � 2,880

27. A vertical tank is 30 ft tall with a diameter of 10 ft. Product level is 15 ft. What is the volumeof the product?

V � 4/3 �r2hV � 3.1416 � 52 � 15 ftV � 1,178.1

28. The product level in Drum 1201 was 950 cubic feet at 4:00 AM. At 8:00 AM, D-1201 has1,950 cu ft of product. No fluid was removed from the drum. Calculate the flow rate into D-1201.(Refer to the volume formulas in Figure 4–14.)

Vin �Vf � Vi 1950 � 950

� 250t 4

Summary

Pressure is defined as force or weight per unit area (Force � Area � Pressure). The term is typi-cally applied to gases or liquids. Pressure is measured in pounds per square inch. Pressure isdirectly proportional to amount: the more of the atmosphere, gas, or liquid, the greater the pressure.At sea level, atmospheric pressure equals 14.7 pounds per square inch.

The boiling point of a substance is the temperature at which the vapor pressure exceeds atmos-pheric pressure, bubbles become visible in the liquid, and vaporization begins.

Vapor pressure, which is the weight of a liquid’s vapor, is directly related to the strength of the mo-lecular bonds of a substance. The stronger the bonds or molecular attraction, the lower the vaporpressure. If a substance has a low vapor pressure, it will have a high boiling point.

As the pressure increases, the boiling point increases and the escape of molecules from the sur-face of the liquid is reduced proportionally. The vapor phase above a liquid could be forced backinto solution.

Any pressure below atmospheric pressure (14.7 psi) is referred to as a vacuum. Vacuum lowersthe boiling point of a substance; enhances molecular escape of liquid; and reduces energy costs,molecular damage due to overheating, and equipment damage.

Robert Boyle, an Irish scientist, developed the law that describes how the volume of a gas re-sponds to pressure changes. The basic principles of Boyle’s law are: Pressure decreases volumeand moves gas molecules closer together; the higher the pressure, the smaller the volume; andgas volume decreases by one-half when pressure doubles.

Pascal’s law states that pressure in a fluid is transmitted equally in all directions, molecules in liq-uids move freely, and molecules are close together in a liquid. The pressure a liquid exerts on a

Summary

109

container is determined by the height and the weight of the fluid (Height � 0.433 � Specific Grav-ity � Pressure).

The principles of liquid pressure are:• Liquid pressure is directly proportional to the density of the substance.• Liquid pressure is proportional to the amount of the liquid.• Liquid pressure is exerted in a perpendicular direction on the walls of a vessel.• Liquid pressure is exerted equally in all directions.• Liquid pressure at the base of a tank is not affected by the size or shape of the tank.• Liquid pressure transmits applied force equally, without loss, inside an enclosed

container.

Three different types of pressure gauges are used in industrial environments: absolute (psia),gauge (psig), and vacuum (psiv). Absolute pressure is equal to gauge pressure plus local atmos-pheric pressure (14.7 psi). Gauge pressure is equal to the absolute pressure minus the local at-mospheric pressure (14.7 psi). Vacuum is typically measured in inches of mercury. Any pressurebelow atmospheric pressure (14.7 psi) is called vacuum.

Liquids are considered to be noncompressible; gases are very compressible. Dalton’s law (Ptotal �P1 � P2 � P3) states that the total pressure of a gas mixture is the sum of the pressures of theindividual gases.

Heat is a form of energy caused by increased molecular activity. A basic principle of heat is that itcannot be created or destroyed, only transferred from one substance to another. Heat moves fromhot areas to cold areas, transferring energy as it goes.

Heat is measured in energy units called British thermal units (Btus). A Btu is the amount of heatneeded to raise one pound of water one degree Fahrenheit.

The effects of absorbed heat are:• Increase in volume• Increase in temperature• Change of state (solid, liquid, or gas)• Chemical change (matches)• Electrical transfer (thermocouple)

Heat comes in a variety of forms. Sensible heat can be sensed or measured. Temperature can beincreased or decreased. Latent heat is hidden heat that does not cause a temperature change.Latent heat of fusion is required to melt a substance. Heat is removed to freeze a substance. Latentheat of vaporization is required to change a liquid to gas. Latent heat of condensation is requiredto condense a gas. Specific heat is the Btus needed to raise one pound of a specific substanceone degree Fahrenheit.

Heat is transmitted through conduction (transfer through a solid object), convection (transfer froma heat source through fluid currents), and radiation (transfer of energy through space by means ofelectromagnetic waves).

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By measuring the hotness or coldness of a substance, we determine temperature. Process oper-ators use a variety of temperature systems. The four most common are Kelvin (K), Celsius (C),Fahrenheit (F), and Rankine (R). Temperature conversion formulas are available to be used byprocess technicians.

A fluid can be classified as a liquid or a gas. When a liquid is in motion, it remains in motion untilit reaches its own level or is stopped.

Bernoulli’s principle states that in a closed process with a constant flow rate, changes in fluid ve-locity (kinetic energy) decrease or increase pressure; kinetic-energy and pressure-energychanges correspond to pipe-size changes; pipe-diameter changes cause velocity changes; andpressure-energy, kinetic-energy (fluid velocity), and pipe-diameter changes are related.

Industry commonly uses the term viscosity to describe the flow characteristics of a substance.Vis-cosity is defined as a fluid’s resistance to flow.

Process technicians use four different ways to express a fluid’s heaviness: density (the mass of asubstance per unit volume), specific gravity (the ratio of a fluid’s density to the density of water orair), baume gravity (the standard used by industrial manufacturers to measure nonhydrocarbonheaviness), and API gravity (based on the American Petroleum Institute’s standards for measur-ing the heaviness of a hydrocarbon using API’s specially designed hydrometer; high API readingsindicate low fluid gravity). Operators commonly confuse specific gravity with density. Density is theheaviness of a substance, whereas specific gravity compares this heaviness to a standard andthen calculates a new ratio. Most hydrocarbons have a specific gravity below 1.0.

Two major classifications of fluid flow are laminar and turbulent. Laminar or streamline flow movesthrough a system in thin cylindrical sheets of liquid flowing inside one another.Turbulent flow is therandom movement or mixing of fluids. Turbulent flow allows molecules of fluid to mix more readilyand absorb heat. Laminar flow promotes the development of static film, which acts as an insula-tor. Turbulent flow decreases the thickness of static film.

Industrial forms of liquid energy include kinetic energy (fluid motion), pressure and potential en-ergy (stored energy, liquid head, internal pressure), and heat energy (fluid friction).

Process technicians use a variety of mathematical and scientific functions to perform their normaljob responsibilities.

Summary

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Chapter 4 Review Questions1. Bernoulli’s principle states that in a closed process with a constant flow rate:

a. changes in fluid velocity (kinetic energy) decrease or increase pressure.b. kinetic-energy and pressure-energy changes correspond to pipe-size changes.c. pipe-diameter changes cause velocity changes.d. all of the above.

2. As the pressure increases inside a confined space:a. the boiling point increases.b. the escape of molecules from the surface of the liquid is increased proportionally.c. the gas or vapor molecules are forced closer together.d. a and c.

3. Solve for y: 62 � 13y � 3

4. Solve for x : 2x � 9

5. Pressure is directly proportional to:a. amount (height). c. specific gravity.b. sound. d. mathematics.

6. Atmospheric pressure is:a. 14.3 psi. c. 14.7 psi.b. 14.5 psi. d. 15.7 psi.

7. True or false? Heat and temperature are basically the same thing.

8. An example of fluid flow is:a. turbulent. c. kinetic.b. gravity. d. potential.

9. Boyle’s law describes how:a. the volume of a gas responds to pressure changes.b. pressure in a fluid is transmitted equally in all directions.c. the volume of a liquid responds to pressure changes.d. kinetic-energy and pressure-energy changes correspond to pipe-size changes.

10. True or false? A liquid need not reach its boiling point to begin the process of evaporation.

11. Calculate the pressure produced by a 2,000-lb stone block, 12-in. length � 12-in. width �12-in. height

Pressure � Force (weight) � Area

12. Calculate the pressure exerted on a 26-ft column filled with 13 ft of gasoline. The vaporpressure of gasoline at 100°F is 12 psi.

Equipment OneAfter studying this chapter, the student will be able to:

• Describe the basic hand tools used in industry.• Identify and describe the valves used in industry.• Describe the various types of storage and piping used in the chemical

processing industry.• Identify the operation and primary components of centrifugal and axial

pumps.• Explain the operation and types of positive displacement pumps.• Describe dynamic and positive displacement compressors.• Describe how a steam turbine works.• Describe the purpose of seals, bearings, and lubrication.

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Chapter 5 ● Equipment One

Key TermsBasic hand tools—term used to describe the typical tools that process technicians use toperform their job activities.

Compressor—a device designed to accelerate or compress gases. Compressors come in twobasic designs: (1) positive displacement (rotary and reciprocating), and (2) dynamic (axial andcentrifugal).

Cyclone—a device used to remove solids from a gas stream.

Demineralizer—a filtering-type device that removes dissolved substances from a fluid.

Filter—device that removes solids from fluids.

Lubrication system—system that includes a lubricant reservoir, pump, valves, heat ex-changer, and piping.

Piping—used in industry to safely contain and transport chemicals; composed of a variety ofmaterials and configured in a variety of shapes and designs.

Pumps—used primarily to move liquids from one place to another. Pumps come in two basicdesigns: (1) positive displacement (rotary and reciprocating), and (2) centrifugal.

Steam trap—a device used to remove condensate from steam systems.

Steam turbine—energy-conversion device that converts steam energy (kinetic energy) to use-ful mechanical energy. Steam turbines come in two basic designs: (1) condensing and (2) non-condensing. They are used as drivers to turn pumps, compressors, electric generators, andpropeller shafts (e.g., on naval vessels).

Strainer—a device used to remove solids from a process before they can enter a pump anddamage it.

Tanks—vessels that store and contain fluids. Tank designs include spherical, open-top,floating-roof, drum, and closed styles.

Valve—a device designed to control (stop, start, or direct) the flow of fluids.

5.1 Basic Hand Tools

Basic hand tools are the usual tools that process technicians typically use to perform their jobactivities (Figure 5–1). Union plants may have limitations on the type of work a process tech-nician may perform. In these plants, the process technician may not be allowed to cross craftsand use hand tools except on a limited basis. In nonunion plants, hand tool usage plays onlya minor role, as skilled craftspersons are available for complex jobs. However, process tech-nicians are required to perform routine maintenance on their units, since most mechanicalcraftspersons work the day shift and leave the evening and night shifts open for callouts. Whena callout is required, the company typically pays time and a half, so it gets expensive. Also, inaddition to the money issue, it takes time for the maintenance staff to return to the work site.Because of these facts, many companies require routine maintenance on the off shift(s) to be

handled by process technicians. In some cases, a little minor maintenance can prevent majorequipment damage.

Here is a list of some basic hand tools:Pliers Wire cutters Needle-nose pliersChannel locks Vice grips Phillips screwdriverFlat-head screwdriver Pipe wrench Crescent wrenchRatchet and socket sets Hammer Utility knifeChisels File Wire brushHacksaw LevelAllen wrenches Wrenches—metric, English, open, box, combination

5.2 Valves

A valve is a device designed to control the flow of fluid through process piping. Following are someof the different types of valves that are used in industry.

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5.2 Valves

Pliers

Phillips screwdriver

Crescent wrench

Channel locks

Open end wrench

OpenBox

Needle nose pliers

Pipe wrench

Flat head screwdriver (plain slotted)

Figure 5–1 Basic Hand Tools

Gate ValvesA gate valve places a movable metal gate in the path of a process flow in a pipeline. Gate valvescome in two designs: (1) rising stem and (2) nonrising stem. Located at the top of a closed gatevalve is the hand wheel. The hand wheel is attached to a threaded stem. As the hand wheel isturned counterclockwise, the stem in the center of the hand wheel begins to rise.This lifts the gateout of the valve body and allows product to flow. Another type of rising-stem valve is threaded atthe bottom of the stem. In this type of valve, the hand wheel is firmly attached to the stem and riseswith it as the valve is opened.

A nonrising-stem gate valve has a collar that keeps the stem from moving up or down. The handwheel is firmly attached to the stem of a nonrising gate. Turning the hand wheel screws the steminto or out of the gate. The basic components of a gate valve are illustrated in Figure 5–2.

Globe ValvesA globe valve places a movable metal disc in the path of a process flow. This type of valve is themost common used for throttling service. The disc is designed to fit snugly into the seat and stopflow. Process fluid enters the globe valve and is directed through a 90-degree turn to the bottomof the seat and disc. As the fluid passes by the disc, it is evenly dispersed.

Globe valves are designed to be installed in high-use areas. If a globe valve is installed in a low-use area, it tends to plug up even if it has a self-cleaning design. Globe valves come in the follow-ing designs: typical globe valve with ball, plug, or composition element; needle valve; and anglevalve. Globe valves and gate valves have very similar components, as illustrated in Figure 5–3.

Ball ValvesBall valves (see Figure 5–4) take their name from the ball-shaped, movable element in the centerof the valve. Unlike a gate or globe valve, a ball valve does not lift the flow control device out of theprocess stream; instead, the hollow ball rotates into the open or closed position. Ball valves offervery little restriction to flow. Most can be opened 100% with a quarter turn of the valve handle,

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BodyWedge

Seat Ring

Wedge PinBonnet Bolt

BonnetGasket

Bonnet Bolt Nut

StemBonnet

Gland BoltPacking

Yoke BushingHandwheel

Gate

Stuffing Box

Figure 5–2 Gate Valve

although some larger valves require hand wheels and gearboxes for opening. In the closed posi-tion, the port is turned away from the process flow. In the open position, the port lines up perfectlywith the inner diameter of the pipe.

Plug ValvesQuick-opening, one-quarter-turn plug valves are very popular in the manufacturing industry. Theplug valve takes its name from the plug-shaped flow control element it uses to regulate flow. Plugvalves provide very little restriction on flow, and can be opened 100% with a quarter turn of thevalve handle. In the closed position, the port is turned away from the process flow. In the open po-sition, the port lines up perfectly with the inner diameter of the pipe.

5.2 Valves

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Hand Wheel

Yoke Sleeve

Stem

Gland Flange

Packing Gland

Packing

Bonnet

Body

Disc

Seat

Disc Nut

Gland Bolt

Gasket

Stuffing Box

Inlet

Figure 5–3 Globe Valve

Joint Bolt Washer

Stem

Gland Bolt

Packing

Washer

Seat

Ball

Body

Lever

Seat

Ball Inlet

Figure 5–4 Ball Valve

Check ValvesA check valve (see Figure 5–5) is a type of automatic valve designed to control flow direction andprevent possible contamination or damage to equipment. The check valve will prevent backflowas long as the device is operating properly. Check valves come in a variety of designs and appli-cations. Typical designs include:

• Swing check, which has a hinged disk that slams shut when flow reverses. Flow liftsthe disc and keeps it lifted until flow stops or reverses. The body of the check valvehas a cap for easy access to the flow control element.

• Lift check, which has a disc that rests on the seat when flow is idle and lifts when flowis active. Special guides keep the disc in place. Like the swing check, it is designed toclose when flow reverses. Lift checks are ideal for systems where flow rates fluctuate.The lift check is more durable than a swing check.

• Ball check, which has a ball-shaped disc that rests on a beveled, round seat. The ballis down when flow is idle and up when flow is active. Special guides keep the balldisc in place. Like the swing check, it is designed to close when flow reverses. Ballchecks are ideal for systems where flow rates fluctuate. The ball check is as durableas a lift check and more durable than a swing check.

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Flow Discharge

Bonnet

Body

Disc

Gasket

Guide

Flow

Bonnet Cover Nut

GasketHinge Pin

Body

Disc

Swing Check Valve

Lift Check Valve

Stop Check Valve

Ball Check Valve

Bonnet

Body

Ball

Bonnet Bolt

Bonnet Nut

Flow

Seat

Flow

Figure 5–5 Check Valves

• Stop check, which combines design characteristics of both a lift check and a globevalve. In the closed position, the stop check disc is firmly seated. In the open posi-tion, the stem rises out of the body of the flow control element and acts like a guidefor the disc. In the open position, the stop check valve functions like a lift check valvewith one exception: The degree of lift can be controlled.

Butterfly ValveA valve commonly used for throttling and on-off service is a butterfly valve. The body of this typeof valve is relatively small compared to other valves, and therefore it occupies much less spacein a pipeline. The flow control element closely resembles a well-worn catcher’s mitt. A metal shaftextends through the center of the “mitt” and allows the disc to rotate one-quarter turn. A quarterturn is all it takes to open the valve 100%.

Diaphragm ValveIn a chemical plant, a variety of corrosive or sticky substances is transferred from place to place.Standard valves would have a difficult time with this type of product, but diaphragm valves arespecifically designed for the job. Diaphragm valves use a flexible diaphragm and seat to regulateflow. The hand wheel on this type of valve operates just like that on a gate or globe valve. Thestem is attached to the center of a flexible diaphragm. The diaphragm rests on the seat. The in-ternal parts of the valve never come into contact with the process. The diaphragm forms a sealand holds the seal until the process pressure overcomes the control pressure. Diaphragm valvesare typically used in low-pressure applications. Diaphragm valves come in two designs:

• Weir diaphragm valve—has a weir located in the body of the valve. Flow must go overthe top of the weir and lift the compressor to exit. There is a large pressure drop acrossthe body of the valve. This valve uses thicker, more durable diaphragm material.

• Straight-through diaphragm valve—flexible diaphragm extends across the pipe.There is very little pressure drop across this type of valve.

Diaphragm valves handle corrosive fluids, have good throttling capability, and are used in low-pressure applications. These valves are used in operations that have moderate temperature andpressure fluctuations.

Relief ValvesRelief valves are designed to respond automatically to sudden increases in pressure. A relief valveopens at a predetermined pressure. In a relief valve, a disc is held in place by a spring that will notopen until system pressure exceeds its operating limits. Tremendous pressures can be generatedin process units. When a system overpressurizes, safety valves respond to allow excess pressureto be vented to the flare header or atmosphere. This prevents damage to equipment and person-nel. Relief valves are designed to open slowly, and thus are best for pressurized liquid service.They do not respond well in gas service, where quicker pressure reduction is needed.

Safety ValveSafety valves are considered to be a process system’s last line of defense. They are designed torespond quickly to excess vapor or gas pressure.This type of valve is very similar in design to a re-lief valve. The three major differences between a relief valve and a safety valve are (1) liquid ver-sus gas service, (2) pressure response time, and (3) size of exhaust port. Relief valves aredesigned to lift slowly, whereas safety valves tend to pop off. Because the exhaust port is much larger

5.2 Valves

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in a safety valve, it can release more flow at much lower velocities. This keeps the trim from beingdamaged. Figure 5–6 is an illustration of a safety valve.

Automatic ValvesThe chemical processing industry uses a complex network of automated systems to control itsprocesses. The smallest unit in this network is called a control loop. Control loops usually have(1) a sensing device, (2) a transmitter, (3) a controller, (4) a transducer, and (5) an automaticvalve. Automatic valves (see Figure 5–7) can be controlled from remote locations, making them

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Outlet

Inlet

Adjustment Screw

Lock Nut

Spring

Washer

Cap

SeatDisc or Feather

Body

Stem or Spindle

Release Lever

Huddling Chamber

Figure 5–6 Safety Valve

Bonnet

Body

Disc

Gasket

Gland Flange

Packing Gland

Packing

Actuator

Stuffing BoxGland Bolt Pin

Air to Close

Flow

Heavy Spring

Solenoid ValveAutomatic Valve

Wire Coil

Armature

Figure 5–7 Automatic Valves

invaluable in modern processing. Any of the valves described in this chapter can be automated.To automate a valve, a device known as an actuator is installed. The actuator controls the posi-tion of the flow control element by moving and controlling the position of the valve stem. Actua-tors can be classified as pneumatic, hydraulic, or electric.

5.3 Piping and Storage Tanks

Industrial piping is composed of a variety of metals and other materials, and is configured in avariety of shapes and designs to safely contain and transport chemicals. The engineering designteam carefully selects the types of materials that are compatible with the chemicals and opera-tional conditions. Piping can be composed of stainless steel, carbon steel, iron, plastic, or spe-cialty metals. Individual joints can be threaded on each end, flanged, welded, or glued.

A wide array of fittings are used to connect piping. The various types of fittings include couplings,unions, elbows, tees, nipples, plugs, caps, and bushings. Figure 5–8 illustrates the various typesof fittings and piping.

The chemical processing industry uses a variety of tanks, drums, bins, and spheres to storechemicals. The most popular designs are shown in Figure 5–9. The materials used in these de-signs include carbon steel, stainless steel, iron, specialty metals, and plastic. Each vessel in-cludes a code stamp that indicates high-pressure and temperature ratings, manufacturer, date,type of metal, storage capacity, and special precautions. Most vessels include strapping tablesthat allow a technician access to data that can be used to identify capacity.

Aboveground storage vessels that have pressures greater than 15 psig are governed by theASME Code, Section V111. Common storage designs include spheres, spheroids, horizontalcylindrical tanks (drums), bins, and fixed- and floating-roof tanks. Tanks, drums, and vessels aretypically classified as low pressure, high pressure, liquid service, gas service, insulated, steamtraced, or water cooled.Wall thickness and shape often determine the service for a stationary ves-sel. Some tanks are designed with internal or external floating roofs, double walls, dome or cone


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Nipple Elbow Plug

90˚ 45˚

Tee Cap Union

CouplingBushing

StrainerBell Reducer

Elbow

Flange

Figure 5–8 Pipe Fittings

roofs, or open tops. Earthen or concrete dikes often surround a tank and are designed for con-tainment in the event of a spill.

Spherical and spheroidal storage tanks are designed to store gases or pressures above 5 psi.Spheroid tanks are flatter than spherical tanks. Figure 5–9 illustrates each of these designs. Hori-zontal cylindrical tanks or drums can be used for pressures between 15 and 1,000� psig. Floating-roof storage tanks are used for materials near atmospheric pressure. In the basic design, a voidforms between the floating roof and the product, forming a constant seal. The primary purpose ofa floating roof is to reduce vapor losses and contain stored fluids. In areas of heavy snowfall, an in-ternal floating roof is used in combination with an external roof, because the weight of the snowwould affect the seal. Nitrogen blankets are also used to put pressure on the surface of a liquid andmake the atmosphere inert. Vapor recovery systems are used to prevent hydrocarbons from es-caping into the atmosphere.

Process technicians often inspect their stationary vessels using the following methods: listen,touch, look, feel, and smell. An experienced technician can identify a problem by listening for ab-normal sounds and vibrations.Touching the equipment allows a technician to identify unusual heatpatterns. Visually inspecting tanks through the gauge hatch and sump levels allows a technicianto look at a questionable tank and determine corrective action. Figure 5–10 shows a typical tankarrangement.

FiltersThe chemical processing industry has adopted the practice of using surface water for industrialapplications instead of well water. When large quantities of water are pulled out of the ground, theupper layers of soil drop. Some residences in heavily industrialized areas have seen the ground

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Bin Tank

DrumDome Roof Tank Open Top Tank

TankSphere

Internal FloatingRoof Tank

Cone Roof Tank

Double WallTank

External FloatingRoof

Spherical Storage Tank Horizontal Cylindrical Vessel

Figure 5–9 Tank Designs

level reduced so rapidly that their homes and businesses have been dropped below sea level andflooded. In higher locations, this process can cause foundations to shift or crack, damaging theoverall structure. Because of this problem, chemical manufacturers bring water in from local riversand lakes. The water is initially brought into a large water basin where sediments are allowed tosettle. Several large pumps take suction off the basin and transfer the water to filters designedto remove suspended solids. Figure 5–11 illustrates a typical industrial filter.

Strainers, Cyclones, and DemineralizersA strainer removes solids from a process before they can enter a pump and damage it. A cycloneis used to remove solids from a gas stream. A typical cyclone is shaped like a V-bottomed tankwith a port in the top, bottom, and upper side. Gases and solids enter the top upper side of thetank and are swirled around the tank. Solids drop to the bottom of the cone while gases escapeout the top of the tank. Demineralizers remove dissolved substances from a fluid.


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Raw Water

Freeboard

Cullsan P

Cullcite

Cullsan A

Cullsan G50Cullsan U

Cullsan Medium

Two LayersUnderbedding

Filtered water

Figure 5–11 Filter

Figure 5–10 Tank Storage

5.4 Pumps

The chemical processing industry uses pumps to move liquids from one place to another. Pumpscome in a variety of shapes and designs and operate under two very different principles. Dynamic andpositive displacement. Dynamic pumps include centrifugal and axial models. A centrifugal pump usesthe principle of centrifugal force to add energy to a liquid. The primary principle involves spinning theliquid in a circular rotation that propels it outward and into a discharge chute known as a volute. Cen-trifugal force and the design of the volute add energy or velocity to the liquid. As the liquid leaves thevolute, it begins to slow down, creating pressure. Fluid pressure moves the process through the pipes.Axial pumps use a propeller to spin the liquid axially along the rotating shaft in order to move the liq-uid. In each of these pumps, the rotating element is designed to accelerate the flow of liquid.

Positive displacement pumps can be classified as rotary or reciprocating. These types of pumpsare designed to displace liquid with each stroke or rotation of the moving element. Because liq-uids are essentially noncompressible at most operating pressures, severe damage can occur toequipment or personnel if the pump is not lined up correctly. New process technicians are givencareful instruction on the design and operation of pumps.

The first centrifugal pump was designed in 1600 by a Frenchman named Denis Papin.The designwas improved in 1851 by an Englishman named John Appold, who replaced the straight vane witha curved vane impeller. The basic components of a centrifugal pump include: casing, suction eye,volute, wear rings, rotating shaft connected to the impeller, motor, coupling, bearings and seals,discharge nozzle, gearbox, lubrication system, suction and discharge pressure gauges, and iso-lation valves.

Figure 5–12 shows the basic components of a single-stage, horizontally mounted centrifugalpump. Liquid is pushed into the suction eye as the liquid level in the feed tank is carefully adjusted

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VoluteSuctionEye

WearRings

Packing Gland

Packing

MotorDischarge

Casing

Impeller

Rotating Shaft

Coupling

Figure 5–12 Centrifugal Pump

to provide the proper net positive suction head (NPSH). A pump curve is used to set up the cor-rect operating condition for a centrifugal pump. Efficiency curves include multiple values: gallonsper minute (gpm) and differential head (discharge head minus suction head).

Centrifugal pumps can be classified as horizontally mounted or vertically mounted, single stageor multistage (more than one impeller). Operating problems associated with centrifugal pumps in-clude cavitation and vapor lock. Cavitation occurs when air pockets form and collapse inside thevolute; actually, the liquid in the pumping chamber is boiling. The phenomenon of rapid expansionand collapse wreaks havoc on the internal parts surrounding the suction eye. When a pump cav-itates, it sounds like marbles being blended in a high-speed mixer. Vapor lock occurs when an airpocket forms inside the pump, preventing the intake and discharge of liquid. Centrifugal pumpsare designed to run only when full of liquid, and cannot tolerate air pockets.

Figure 5–13 shows both vertically and horizontally mounted centrifugal pumps. Suction and dis-charge pressures must be carefully controlled if these pumps are to operate correctly. Most ofthese factors are taken into consideration during the engineering design; however, liquid levelsand line-ups are variables that can change.

Figure 5–14 shows a typical family tree for the dynamic pump family. Centrifugal pumps are oftenused in jet pump systems. A jet pump uses a unique design on the suction side of the pump tocreate a venturi effect as a portion of the discharge is pushed down the casing and back into thesuction line. This process provides the lift needed to raise liquid levels that are lower than 40 feet.

Single-stage centrifugal pumps can operate for short periods of time with the discharge closedbecause of the principle of internal slip. Internal slip is the percentage of fluid that leaks or slipspast the internal clearances of a pump over a given time. Because the impeller does not physi-cally come into contact with the casing, the liquid slips between the fixed and moving parts. It is acommon practice to “press up” a line by closing a discharge valve down the line in a pipeline; how-ever, large multistage centrifugal pumps can be damaged by this procedure.

5.4 Pumps

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Figure 5–13 (a) Horizontal Centrifugal Pump (b) Vertical Centrifugal Pump

Axial pumps are composed of a motor, coupling, bearings, seals, propeller, and shaft. As the pro-peller turns, fluids are propelled axially along the shaft. This feature operates in a manner similarto the way a ceiling fan moves air around a room. Other examples include a boat propeller and abox fan. Figure 5–15 shows the basic components of an axial pump.

Positive Displacement PumpsPumps that operate by displacing fluid positively are classified as positive displacement (PD)pumps. The two primary designs are rotary and reciprocating. It is important for the processtechnician to understand, before use, how any piece of equipment operates; this is especiallytrue with PD pumps, which are not as forgiving as centrifugal pumps. Correct alignment of a PDpump is critical in operation, because these pumps are designed to positively displace liquid oneach stroke or rotation. Inside an enclosed vessel, a liquid transfers pressure instantly equallyin all directions. For this reason, liquids should be considered noncompressible. Process tech-nicians must never leave a valve closed on the discharge side of the pump, or serious conse-quences will result.

Rotary Pumps. Rotary pumps are characterized by a rotary movement; types include screw, lobe,vane, and gear. Figures 5–16 and 5–17 illustrate rotary-type pumps. Rotary pumps displace liquidwith gears, vanes, screws, or other rotating elements. The common thread between these twogroups is the positive displacement action of the device. Centrifugal pumps are often mistakenly

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CENTRIFUGAL

Multistage

AXIAL

Vertical

Horizontal

Single Stage

DYNAMIC

Figure 5–14 Dynamic Pump Family Tree

Driver

CouplingMechanical Seal

Thrust andRadial Bearings

Propeller

Figure 5–15 Axial Pump

considered rotary designs; however, although the impeller on a centrifugal pump does rotate, theliquid is not positively displaced. This is the primary distinction between rotary and centrifugalpumps.

Rotary pumps include single-screw, twin-screw, or three-screw pump operation. Vane pump de-signs include flexible-vane and sliding-vane types. Gear pumps include internal and external gearpumps. Lobe pumps have moving elements that resemble twin-turning lobes that use timinggears to keep them from coming into contact with each other. The positive displacement pumpfamily tree in Figure 5–18 shows some of the differences between these pumps.

Reciprocating PumpsReciprocating pumps include piston, plunger, and diaphragm designs. This type of pumpdraws a specific volume of liquid into a chamber on the intake stroke and positively displacesthis volume with a piston, plunger, or diaphragm on the discharge stroke. Typically, a series offlow-regulating check valves are used on the inlet and outlet lines. Reciprocating pumps arecharacterized by a back-and-forth movement, similar to the pumping action of an old-fashioned, hand-operated water pump. Figures 5–19 and 5–20 show examples of reciprocat-ing pumps. The basic components of a reciprocating pump include a connecting rod,piston/plunger or diaphragm, seals, check valves, motor, cylinder or pumping chamber, cas-ing, and bearings.

5.4 Pumps

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Base

SuctionDischarge

Cooling Water Jacket

Casing Off-Center Rotor

Vanes

Sliding Vane PumpExternal Gear PumpLobe Pump

Suction Discharge Suction Discharge

PowerGear

Idler Gear

Figure 5–16 Rotary Pumps

Suction Discharge

External Gear Pump

Power Gear

Idler Gear

Figure 5–17 External Gear Pump

Operation of a Positive Displacement PumpThe correct operation of a PD pump includes correctly lining up the pump from the suction tank tothe discharge tank. This includes opening all the suction and discharge valves on the flow path tothe destination tank and closing any valve that is not on that flow path. Adequate liquid level is re-quired on the suction side to operate the pump, and space should be available in the destinationtank. A positive displacement pump is not dependent on NPSH or liquid level; however, adequatesuction is required. Vented and nonvented tanks respond differently during product transfers andshould be carefully monitored.

Positive displacement pumps are not supposed to be throttled or regulated on the discharge side.After the line has been walked and every valve has been checked, the pump can be started. Suc-tion and pressure gauges should be carefully monitored, and flow rates tracked. Flow control loopsare typically not used with PD pumps unless a series of relief valves and pressure control devicesis used. A simple calculation should be made on how fast the tank will fill and how fast the suctiontank will empty. Careful monitoring of liquid levels is important. Samples are frequently caught onthe product lines and sent to the lab for quality checks. Some PD pumps are designed to be runliquid full at all times, whereas others can be run empty for short periods of time.

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ROTARY

!.0 Screw Pump

2.0 External Gear

3.0 Internal Gear

4.0 Sliding Vane

5.0 Flexible Vane

6.0 Lobe Pump

1.0 Piston

2.0 Plunger

3.0 Diaphragm

RECIPROCATING

Progressive Cavity Single

Multiple Timed

Untimed

Spur Helical Herringbone

Timed

Untimed

No Crescent

Crescent

Multiple

Single

Blade, Bucket Roller, Slipper

Vane in Rotor

Vane in Stator POSITIVE

DISPLACEMENT Tube, Vane, Liner

Figure 5–18 Positive Displacement Pump Family Tree

5.5 Compressors

The operation and design of a compressor can usually be classified into one of two groups: pos-itive displacement or dynamic. Dynamic compressors operate by accelerating the gas and con-verting the energy to pressure. This type of compressor can be either centrifugal or axial.Centrifugal compressors (see Figure 5–21) operate by adding centrifugal force to the product

5.5 Compressors

129

XXXXX

XXXXX

Check Valve

Packing

Packing GlandSuction

Discharge

Piston

Piston Rings

Piston Pump

Figure 5–19 Reciprocating Pumps Figure 5–20 Piston Pump

Figure 5–21 Centrifugal Compressor

Discharge

Impeller

Shaft

Suction Eye

Wear Rings

Gland

Diffuser Plates

Casing

stream. The design and application of centrifugal compressors accelerate the velocity of thegases. This velocity or kinetic energy is converted to pressure as the gas flow leaves the voluteand enters the discharge pipe. Centrifugal compressors can deliver much higher flow rates thanpositive displacement compressors.

The basic components of a centrifugal compressor include the casing, motor or driver, coupling,volute, suction eye or inlet, impellers, wear rings, seals, bearings, discharge port, suction gauge,and discharge gauge. An axial flow compressor is composed of a rotor that has rows of fan-likeblades. Unlike centrifugal compressors, axial compressors do not use centrifugal force to increasegas velocity. Instead, airflow is moved axially along the shaft. Rotating blades attached to a shaftpush gases over stationary blades called stators. The stators are mounted or attached to the cas-ing. As the gas velocity is increased by the rotating blades, the stator blades slow it down. As thegas slows, kinetic energy is released in the form of pressure. Gas velocity increases as it movesfrom stage to stage until it reaches the discharge port. Figure 5–22 shows a single-stage cen-trifugal blower.

Positive Displacement CompressorsPositive displacement compressors (see Figure 5–23) operate by trapping a specific amountof gas and forcing it into a smaller volume. They are classified as rotary or reciprocating.Positive displacement compressors and positive displacement pumps operate in a similarfashion. The primary difference is that compressors are designed to transfer gases andpumps are designed to move liquids. A rotary compressor design includes a rotary screw,sliding vane, lobe, and liquid ring. A reciprocating compressor includes a piston (Figure 5–24)and diaphragm.

130


Figure 5–22 Blower

5.5 Compressors

131

Figure 5–23 Positive Displacement (PD) Compressor

Figure 5–24 Piston Compressor

Foundation

Valves

Connecting Rod

Crank Pinand

Main Bearings

Piston

Piston Compressor

Counterweights

Suction Line

Driver

Connecting Rod

Crankshaft

Piston

Cylinder

Piston Rings

Discharge Line

Sealsand Shaft

5.6 Steam Turbines

A steam turbine is a device “driver” that converts kinetic energy (steam energy of movement) tomechanical energy. Steam turbines have a specially designed rotor that rotates as steam strikesit. This rotation is used to operate a variety of shaft-driven equipment. The steam used to oper-ate a steam turbine is produced in a boiler. Boilers produce steam that can enter a turbine at tem-peratures as high as 1,000°F, and pressures as high as 3,500 psi inlet and 200 psi outlet.High-pressure steam is slowly admitted into a turbine to warm it up and remove the condensate.

Steam enters a turbine through the steam chest. The steam chest typically has a strainer on theinlet side to remove solids. Inside the steam chest is a device called the governor valve. The gov-ernor valve opens and closes to admit steam into the turbine. A governor system controls the po-sition of the governor valve. An overspeed trip mechanism is attached to the rotor and will shut offthe flow of steam into the turbine when it reaches 115% of its design limit.The shutoff valve is typ-ically located in front of the governor valve.

As steam leaves the steam chest, it is directed into the nozzle block.The nozzle directs the steamonto the blading, which is attached to the shaft. The blading and shaft make up the rotor. Impulseor reaction movement occurs as the steam strikes the rotor, converting the steam energy into me-chanical energy. Each stage consists of a set of moving and stationary blades. The curved bladesof each stage are designed so the spaces between the blading act like the nozzle to increasesteam velocity. As the steam zigzags between the stationary and moving blades, it expands to asmuch as 1,000 times its original volume. Modern turbine design increases the size of each stage,giving the turbine a conical shape.

Steam turbines are typically classified as condensing, noncondensing, impulse, or reactive. In the con-densing design, a heat exchanger is used to condense the steam. In contrast, the noncondensing de-sign utilizes the exhaust as low-pressure steam. Impulse and reactive movement describe how thesteam acts upon the rotor. In the reactive design, the nozzle is mounted on the rotor, whereas the im-pulse design allows the steam to blow against the rotor. Reactive movement is a reactive response tothe release of steam. Steam turbines are used primarily as drivers for pumps, compressors, and gen-eration of electric power. Figure 5–25 illustrates the internal components of an impulse steam turbine.

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Steam Inlet

Steam Outlet

Fixed Blades

GovernorSystem

GovernorValve

Thrust Bearings

Radial Bearings

Carbon Rings

Labyrinth Seals

Moving Blades

Casing

Rotating Shaft

Nozzle Block

Rotor

Slinger Ring

Coupling

Figure 5–25 Steam Turbine

5.7 Gas Turbines

The basic components of a gas turbine system (Figure 5–26) fall into four primary areas: the com-pressor, combustion chamber, gas turbine, and load. Each of these areas has a number of criti-cal components and is linked by a common axle (Figure 5–27). Each part of the gas turbinesystem is an integral part of the whole unit. Axial flow compressors have replaced most other com-pressor designs because of the large volume this design can handle. The combustion chambercombines two feed components to produce a continuous, high-pressure flow into the turbine. Thegas turbine has a number of stages that increase in size to accommodate the expanding hotgases that jet through the moving turbine wheels and stationary blades.

Part 1—Compressor• Compressor rotor assembly• Stator blades, rotor blades• Compressor case assembly• Air inlet filter assembly• Bearings and seals• Compressor diffuser assembly

Part 2—Combustion Chamber• Fuel injector• Combustor housing assembly• Gas fuel manifold• Bleed air valve• Ignitor

5.7 Gas Turbines

133

L

L

Air Compressor Combustion Chamber

Workload

Spark PlugAir In Exhaust

Fuel

Gas Turbine

Figure 5–26 Gas Turbine

Part 3—Gas Turbine• Gas producer turbine rotor assembly• Power turbine rotor assembly• Moving turbine wheels and stationary blades• Nozzle case and assembly• Turbine exhaust diffuser• Exhaust collector

Part 4—Workload• Driven shaft• Driven device

5.8 Electricity and Motors

The majority of electrical power produced in the world is alternating current (AC). Alternating cur-rent is defined as current that reverses direction at regular intervals. Most industrial motors use alternating current. Alternating current can be transformed using a step-down or step-uptransformer. Voltage can be increased for the purpose of transmission and then stepped down asit nears the electrical equipment. Voltages between 69 kilovolts (kV), 138 kV, and 345 kV are fre-quently used. Direct current (DC) does not change flow direction, and thus cannot be used in thesame way as alternating current.

134


L

L

Air Compressor

Combustion Chamber

Workload

Spark PlugAir In

ExhaustFuelInjector

Gas Turbine

Compressor Rotor

DiffuserTurbine Rotor

Stationary Blades

Combustor Assembly

Axle

Figure 5–27 Gas Turbine Internals

During the 1904 World’s Fair, Thomas Edison attempted to demonstrate that low-voltage directcurrent could light the fair more economically than the alternating current advocated by GeorgeWestinghouse and Nikola Tesla. Under Edison’s plan, it would have cost $1.00 for every light bulb,versus Westinghouse’s bid of 25 cents per light bulb. Alternating current easily won the contestand has remained the most popular option.

The chemical processing industry uses three-phase motors to operate pumps, compressors,fans, blowers, and other electrically driven equipment. Three-phase motors come in three basicdesigns: squirrel-cage induction motors, wound-rotor induction motors, and synchronous motors.The primary difference is in the rotor. The direction of rotation in a motor is determined by strongmagnetic fields. A typical motor is composed of stator windings, rotor and shaft, bearings andseals, conduit box, frame, fan, lubrication system, and shroud. Figure 5–28 illustrates the locationof these components. Figure 5–29 shows an AC motor.

5.9 Equipment Lubrication, Bearings, and Seals

One of the primary functions a process technician performs is periodic checks of the equipmentsystem. During these routine checks, equipment oil levels and operating conditions are closely in-spected. High temperatures, unusual noises or smells, and erratic flows are all signs that a prob-lem has developed.

LubricationTo ensure the good operation of process equipment, proper lubrication must be maintained. A lubri-cation system protects the moving parts of equipment by placing a thin film of protection betweensurfaces that come into contact with each other (Figure 5–30). Under a microscope, the smooth sur-face of a gear may appear very rough.Without lubrication, a tremendous amount of friction would de-velop. Lubrication helps remove heat generated by friction and provides a fluid barrier between themetal parts to reduce friction. Loss of lubrication causes severe damage to compressors, steam tur-bines, pumps, generators, and engines. Most rotary equipment requires some type of lubrication.

5.9 Equipment Lubrication, Bearings, and Seals

135

Frame

Bearing

Fan

Bearing

Seals

Revolving Magnetic Flux

Wave

Rotor

Stator

Load

RevolvingMagnetic Poles

Electric Power

Bearing Oil

Figure 5–28 Typical Motor

BearingsRadial and axial bearings can be found in most rotating equipment, and require lubrication to op-erate properly. Radial bearings are designed to prevent vertical (up-and-down) and horizontal(side-to-side) movement of the rotating shaft. Axial bearings are designed to prevent back-and-forth movement of the shaft. Radial bearings come in a variety of designs, including ball bearings,friction or sleeve bearings, rolling-element bearings, and shielded bearings.

SealsShaft seals are designed to prevent leakage between internal compartments in a rotating piece ofequipment. Shaft seals come in a variety of shapes and designs. Typical designs include labyrinthseals, carbon seals, packing seals, and mechanical seals. Labyrinth seals trap lubrication and fluidsbetween a maze of ridges. Segmental carbon seals are mounted in a ring-shaped design around therotating shaft. A spring holds the soft graphite seal in place and allows it to wear evenly. Mechanical

136


Figure 5–29 AC Motor

FluidReservoir

CompressorBearings

Gearbox

PumpBearings

Figure 5–30 Lubrication System

seals come in a modular kit that is slid into place as one unit. Mechanical seals provide a stationaryseat and a moving seal face. Mechanical seals are designed to withstand high pressure; carbon sealsand labyrinth seals cannot. Shaft seals minimize air leakage into and out of the equipment; keep dirt,chemicals, and water out of the lubricant; and keep the clean lubricant in the chamber where the bear-ings and moving components are located. Seals and bearings are illustrated in Figure 5–31.

5.10 Steam Traps

Steam traps are used to eliminate condensate from industrial steam systems. Condensate cancause a lot of serious problems as it flows with the steam. Slugs of water can damage equipmentand lead to a condition known as water hammer. To eliminate this problem, steam traps are usedto remove condensate. Steam traps are classified as either mechanical or thermostatic. Figure 5–32

5.10 Steam Traps

137

Outside Ring

Ball BearingRetainer Cage

Inside Ring

Shaft

Thrust or Axial Movement

RadialMovement

Friction Bearing

Seals

Oil

Oil

BottleOiler

Thrust Bearing

Radial Bearing

Shaft

Figure 5–31 Seals and Bearings

Expanded

Contracted

BellowsBucket Trap

Outlet

CapValve

Air Vent

Bucket

Bucket Weight

Inlet

Steam

Condensate

Figure 5–32 Steam Traps

illustrates two different steam-trap designs. Mechanical steam traps include floats and invertedbuckets. Thermostatic traps include bellows-type traps.

Summary

Basic hand tools are the typical tools that process technicians use to perform their job activities.These include tools such as pliers, screwdrivers, wrenches, and channel locks. Process techni-cians are required to perform routine maintenance on their units. A little minor maintenance canoften prevent major equipment damage.

Tanks and pipes store and contain fluids. Tank designs vary depending upon their service. Pipesize and design determine flow rates, pump and valve sizes, turbulent or laminar flow, instrumenttype, and automation. Valves control the flow of fluids. Valves come in a variety of shapes, sizes,and designs that throttle, stop, or start flow. Common valve designs are gate, globe, ball, plug,check, and butterfly.

Filters remove solids from fluids. Strainers remove solids from a process before the solids can en-ter a pump and damage it. A cyclone is used to remove solids from a gas stream. A typical cycloneis shaped like a V-bottomed tank with ports in the top, bottom, and upper side. Gases and solidsenter the top upper side of the tank and are swirled around the tank. Solids drop to the bottom ofthe cone while gases escape out the top of the tank. Demineralizers remove dissolved substancesfrom a fluid.

Pumps are primarily used to move liquids from one place to another.The two basic designs are pos-itive displacement and dynamic. Positive displacement pumps can be classified as rotary or recip-rocating. Reciprocating pumps are characterized by a back-and-forth motion, whereas rotary pumpsmove in a circular fashion. Dynamic pumps can be classified as centrifugal or axial. The centrifugalpump uses centrifugal force to move liquids; axial pumps push liquids along a straight line.

Compressors are closely related to pumps. They come in two basic designs: positive displace-ment (rotary and reciprocating) or dynamic (axial or centrifugal). A compressor is designed toaccelerate or compress gases.

Steam turbines are used as drivers to turn pumps, compressors, and electric generators. High-pressure steam is directed into buckets designed to turn a rotor and provide rotational energy.Steam turbines serve the same function as electric motors. A typical motor is composed of statorwindings, rotor and shaft, bearings and seals, conduit box, frame, fan, lubrication system, andshroud. Steam turbines and motors are two of the most popular devices used by industry as drivers.

Shaft seals are designed to prevent leakage between internal compartments in a rotating piece ofequipment. Typical shaft seal designs include labyrinth seals, carbon seals, packing seals, andmechanical seals. Radial and axial bearings can be found in most rotating equipment and requirelubrication to operate properly. Radial bearings are designed to prevent up-and-down and side-to-side movement of the rotating shaft; axial bearings are designed to prevent back-and-forth move-ment of the shaft.

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Chapter 5 Review Questions

139

Chapter 5 Review Questions1. Draw a gate valve and label its parts.

2. Draw a centrifugal pump and label its parts.

3. What is the primary difference between a pump and a compressor?

4. Describe how a steam turbine works. Sketch a simple drawing if needed.

5. Describe alternating current.

6. Draw a rotary pump and label its parts. Show rotation.

7. Explain the purpose of bearings and seals.

8. What are the basic components of an electrical motor?

9. List the basic hand tools used by process technicians.

10. Describe how a steam trap operates.

11. Draw a globe valve and label its parts.

12. What is the primary purpose of a floating roof?

13. List the standard pipe fittings used to connect pipe.

14. What types of materials are used in the manufacture of storage tanks?

15. How much pressure can a typical horizontal cylindrical tank hold?

16. Draw the type of valve used to relieve pressure, and label its parts.

17. Describe how an industrial motor works.

18. Describe centrifugal movement.

19. Draw a reciprocating pump and label its parts. Show rotation.

20. Explain the importance of lubrication for a pump, compressor, or turbine.

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Equipment TwoAfter studying this chapter, the student will be able to:

• Describe the purpose and components of different types of heat exchangers.• Describe the key components and operation of a cooling tower.• List the primary components of a fire-tube boiler and a water-tube boiler.• Describe the primary components and operation of cabin, cylindrical, and box

furnaces.• Identify the purpose and components of a reactor.• Describe the different types of catalysts: adsorption, intermediate, inhibitor,

and poisoned.• Compare and contrast the various types of chemical reactions: exothermic,

endothermic, replacement, and neutralization.• Describe the purpose and components of plate and packed distillation

columns.• Explain the purpose and components of a typical separator.

141

142

Chapter 6 ● Equipment Two

Key TermsBoilers—devices primarily designed to boil water and generate steam for industrial applica-tions. Boilers are classified as either water tube or fire tube. Steam generation systems producehigh-, medium-, and low-pressure steam for industrial use.

Catalyst—a chemical that can increase or decrease a reaction rate without becoming part ofthe product. Catalysts are classified as adsorption, intermediate, inhibitor, or poisoned.

Chemical reactions—interactions between two or more chemicals in which a new substanceis formed; types include exothermic, endothermic, replacement, and neutralization.

Cooling towers—devices used by industry to remove heat from water. In a typical tower, a box-shaped collection of multilayered slats and louvers directs airflow and breaks up water as itcascades from the top of the water distribution system. Cooling towers are classified by the waythey produce airflow and by the way the air moves in relation to the downward flow of water.Basic designs include atmospheric, natural, forced, and induced draft.

Distillation column—a collection of stills stacked one on top of another; separates chemicalmixtures by boiling points. Distillation columns fall into two distinct classes: plate and packed.

Fire-tube heaters—furnaces consisting of a battery of tubes that pass through a firebox. Firedheaters or furnaces are commercially used to heat large volumes of crude oil or hydrocarbons.Basic designs include cylindrical, cabin, and box.

Fluid flow—movement of fluid particles; can be described as laminar, turbulent, parallel, series,counterflow, or cross-flow.

Heat—a form of energy caused by increased molecular activity. Forms include sensible heatand latent heat.

Heat exchanger—an energy-transfer device designed to convey heat from one substance to an-other. Basic designs include pipe coil, shell-and-tube, air-cooled, plate-and-frame, and spiral.

Heat transfer—movement of heat energy; methods include conduction, convection, and radiant.

Reactor—device used to convert raw materials into useful products through chemical reac-tions. A reactor combines raw materials, heat, pressure, and catalysts in the right proportions.Five reactor designs are commonly used: stirred, fixed-bed, fluidized-bed, tubular, and furnace.

6.1 Heat Exchangers

Heat exchangers transfer energy, in the form of heat, between two fluids without the fluids com-ing into physical contact with each other. A typical shell-and-tube heat exchanger has a tube-sideflow and a shell-side flow. Heat energy is transferred to the cooler stream as the streams passeach other in the exchanger. A standard exchanger has a shell, tubes, tube sheet, shell inlet andoutlet, tube inlet and outlet, and baffles. Heat exchangers fall into the following categories:

• Simple pipe-coil• Shell-and-tube

• Plate-and-frame• Spiral• Air-cooled

Shell-and-tube heat exchangers can be broken down into: (1) pipe-coil; (2) double-pipe; (3) fixed-head, single-pass; (4) fixed-head, multipass; (5) floating-head, multipass (U-tube); (6) kettlereboiler; (7) thermosyphon reboiler; and (8) shell nomenclature. These devices can be mountedvertically or horizontally.

The problems associated with shell-and-tube heat exchanger operation (see Figures 6–1 and 6–2)include fouling, corrosion, tube rupture, shell leaks, gasket leaks, pressure problems related toblockage, product contamination, fires, and explosions. Although these problems are rare, a heatexchanger is still a simple device that can be turned into a bomb by accidentally closing thewrong valve. When a heat source is allowed to flow over trapped liquid, problems can developquickly. Process technicians should carefully monitor inlet and outlet pressures and tempera-tures. These indicators can rapidly identify impending problems. Tube leakage can typically beidentified in product samples.

The transfer of heat (heat transfer) between two fluid streams is an important process in the chem-ical processing industry. The simplest type of heat exchanger is a pipe coil. Copper tubes, whichare easily bent to form, are submerged in water or sprayed with water. This process is very effec-tive in low-volume, low-heat-load operations; however, larger processes require more complex de-vices. Pipe-coil heat transfer devices evolved into a double-pipe design that provided bettertemperature control and became the first true shell-and-tube heat exchanger. A double-pipe heatexchanger has a pipe (tube) within a pipe (shell) design. Fins can be added to the tubes to providegreater surface area and higher heat transfer rates. Thin metal fins conduct heat energy from hotareas to colder areas. A simple double-pipe design is the hair-pin exchanger. Figures 6–3 and 6–4show a simple pipe-coil heat exchanger and a hair-pin heat exchanger.

Another type of heat exchanger is a kettle reboiler. Reboilers are energy-balance devices attachedto distillation columns to help control temperature. Reboilers have two basic designs:

6.1 Heat Exchangers

143

Pass Partition

Support Saddle

TransverseBaffles

Floating Head Cover

Floating Tubesheet

Shell

ShellFlange

Tubes

Shell Nozzle Outlet

Floating Head

Channel Coverand Head

Shell Nozzle Inlet

Floating HeadBacking Device

Tube NozzleInlet

TubeNozzleOutlet

Shell Cover

Fixed Tubesheet

Figure 6–1 Shell-and-Tube Heat Exchanger

thermosyphon and kettle. Thermosyphon reboilers are typically single-pass, shell-and-tube heatexchangers. Kettle reboilers have a specially designed vapor-disengaging cavity that removes thelighter components of the bottom stream. These lighter fractions are returned to the bottom of thecolumn. Process technicians monitor and control the temperature at both the bottom and the topof the column.

Kettle reboilers have five connections, two on the tube side and three on the shell side. Steam or hotoil flows through the tube side and provides the heat source. Flow rate is carefully controlled and fre-quently linked to the bottom temperature control system. The higher the flow rate, the hotter the bot-tom product. The shell side has three nozzles: one liquid-product feed line, one vapor-return line tothe column, and one heavy-liquid-out product line. A kettle reboiler can be used to (1) control the liq-uid level on the bottom of the column, (2) control the temperature of the column, and (3) help controlproduct purity in the bottom of the column. Figure 6-5 shows what a kettle reboiler looks like, andFigure 6–6 shows two thermosyphon and one kettle reboiler arrangements on a distillation column.

144


Figure 6–2 Shell-and-Tube Heat Exchanger

Tube Inlet

Tube Outlet

Figure 6–3 Pipe-Coil Heat Exchanger

6.1 Heat Exchangers

145

Shell Inlet

Shell InletShell Outlet

Shell Outlet

Shell

Tube Inlet

Tube Inlet

Tube Outlet

Tube Outlet

Finned Center Tube

Figure 6–4 Double-Pipe Heat Exchanger

Shell

(Steam) Tube Inlet

(Condensate)Tube Outlet(Liquid) Shell Outlet

Feed In

Shell Nozzle Outlet

Vapor Disengaging Cavity

Vapor

LiquidHead

Figure 6–5 Kettle Reboiler

Along with maintaining the energy balance on a distillation column, a heat exchanger can be usedto preheat the feed. In this type of design, two or more exchangers may be used. As feed entersthe first heat exchanger, the transfer of energy occurs. This process gradually raises the temper-ature of the feed before it enters the second exchanger. As the temperature of the feed increases,

exchangers, like fouling and corrosion.These simple devices are easy to construct and have a lowoperating cost. Figure 6–8 shows what a typical air-cooled heat exchanger looks like.

6.2 Cooling Towers

A cooling tower is a simple device used by industry to remove heat from water. Hot water trans-fers heat to cooler air as it passes through the internal components of the tower. This type of heatis called sensible heat; sensible heat can be measured or felt. Sensible heat accounts for only 10%

6.2 Cooling Towers

147

EX

EX

EX

Hot Oil

Hot Oil

Feed

FeedHeater

Reboiler

Condenser

Figure 6–7 Three Types of Heat Exchangers

StationaryTubesheet

Fan

Tube InletNozzle

Tube InletNozzle

Finned Tubes

Channel Head

Head

Air

Figure 6–8 Air-Cooled Heat Exchanger

pressure increases, and the confined liquid moves toward the column. Temperature is an impor-tant process variable that can influence the operation of the entire system.

Many of the processes found in industry produce vaporized products or partially vaporized prod-ucts. Heat exchangers called condensers or coolers are designed to change the vapor into a moreuseful form. Liquid products are easier to transfer and control than vaporized materials. A goodexample of this process is a distillation system. As lighter components in the feed mixture vapor-ize and move up the column, the flow is directed out the overhead line and into a condenser.A cooling-tower system provides cooling water to the overhead condenser at specific flow rates.Air-cooled heat exchangers are also frequently used in this type of system. Figure 6–7 shows aheat exchanger used as a heater, a kettle reboiler, and a condenser.

Air-cooled heat exchangers are similar in design to shell-and-tube heat exchangers, but do notuse a shell. Air-cooled devices such as car radiators work to remove heat generated by a com-bustion engine. Air-cooled heat exchangers or fin fans are designed to condense or partially con-dense hot vapors from a distillation system.These heat transfer devices are very effective and arewidely used across the process industry. An air-cooled heat exchanger is composed of an inletchannel head and a return head, a series of plain or finned tubes, two tube sheets, and a fan. Thefan can be positioned in a forced-draft or induced-draft position over/under the tubes. Air-cooledheat exchangers have none of the operational problems associated with shell-and-tube

146


HeatingFluid

Horizontal

Kettle Reboiler

EX EX

EX

Figure 6–6 Reboiler Designs

to 20% of the heat transfer in a cooling tower. Most of the heat stripping from a tower is caused byevaporation. Evaporation accounts for 80% to 90% of the heat transfer in a cooling tower. Whenwater changes to vapor, it takes heat energy with it, leaving behind the cooler liquid. The principleof evaporation is the most critical factor in cooling-tower efficiency.

A cooling tower is a large rectangular or box-shaped device filled with wooden or plastic slats andlouvers that direct airflow and break up water as it falls from the top of the water distribution header.The internal design of the tower ensures good air and water contact.

Cooling towers are classified by (1) how they produce airflow, and (2) the direction the airflow takesin relation to the downward flow of water. Airflow may be produced naturally or mechanically. Me-chanical drafts are created by fans located on the side or top of the cooling tower. Flow direction intoa tower is either cross flow or counterflow. Cross flow goes horizontally across the downward flow ofwater before exiting the system. When the air is forced to move vertically upward, against the down-ward flow of water, it is referred to as counterflow. Cooling towers come in the following designs:

Natural Drafts• Atmospheric—simple counterflow• Hyperbolic (chimney towers)—counterflow or cross-flow

Mechanical Drafts• Forced draft—counterflow• Induced draft—counterflow or cross-flow

The basic components of a cooling tower include a water basin, pump, and water make-up sys-tem at the base of the cooling tower.The internal frame is made of pressure-treated wood or plas-tic and is designed to support the internal components of the tower. Some of these componentsinclude the fill or splash boards and drift eliminators. The fill or splash boards enhance liquid aircontact, while the drift eliminators reduce the amount of water lost from the tower because of ex-cess airflow. Louvers on the side of the cooling water tower admit air into the device. A hot-waterdistribution system is typically located on the top of the cooling tower fill. A fan may be used to en-hance airflow through the cooling tower. Fan location determines whether airflow is induced (drawnin) or forced (pushed in). Figures 6–9 and 6–10 show typical cooling towers. Additional informationabout cooling towers can be found in Chapter 9. (See Figure 6–11.)

148


VV

VV

VV

V

V

V

V

V

VV

VV

VV

VV

VV

V

VV

V

VV

VV

V

V

V

V

V

V

V

V

V

V

V

V

V

V

Cold Water Basin

Fan

DriftEliminators

Louvers

Pump

Return Line

To Process

Air In Fill

Water Distribution System Hot Water Header

Make-upWater

Air In

Figure 6–9 Induced-Draft Cooling Tower

6.3 Boilers (Steam Generation)

Steam generators, commonly called boilers, are used by industrial manufacturers to produce steam.Steam is used to drive turbines and provide heat to process equipment. Steam generators are clas-sified as fire-tube or water-tube boilers. High-pressure, medium-pressure, and low-pressure steam is

6.3 Boilers (Steam Generation)

149

Solid Walls

Water DistributionSystem

Water BasinMake-up Water

Fan

Drift EliminatorsHot Water Return

Cold Water Out

EX

EX

EX

Figure 6–10 Forced-Draft Cooling Tower

Figure 6–11 Cooling Tower

circulated and used in numerous applications within a typical plant. Water-tube boilers are typicallydesigned for large industrial applications; fire-tube boilers are used in smaller systems and processes.

Fire-Tube BoilersFire-tube boilers contain the combustion gases in tubes that occupy a small percentage of theoverall volume of the heater. The heated tubes run through a shell that contains the heatedmedium (water). A fire-tube boiler resembles a multipass shell-and-tube heat exchanger.This typeof boiler is composed of a shell and a series of steel tubes designed to transfer heat through thecombustion chamber (tube) into the horizontal fire tubes. Exhaust fumes exit through a chambersimilar to an exchanger head and pass safely out of the boiler. The water level in the boiler shell ismaintained above the tubes to protect them from overheating. The term fire tube comes from theway the boiler is constructed.

The basic components of a fire-tube boiler include a large shell that surrounds a horizontal seriesof tubes. A large, lower combustion tube is attached to a burner that admits heat into the tubes.The upper tubes transfer hot combustion gases through the system and out the stack. Airflow isclosely controlled with the inlet air louvers and the stack damper. Water level in the shell is main-tained slightly above the tubes. As heat energy is transferred into the water, the temperature risesuntil the fluid boils. A pressure control valve maintains the correct operating pressure on the ves-sel. Every fire-tube boiler is equipped with a pressure relief system. A series of safety valves maybe located on the discharge side of the shell. Low-pressure steam is discharged into a commonsteam header that is connected to various locations in the facility. A condensate return line admitsthe condensed steam into a deaerator drum and the water make-up system. Figure 6–12 illus-trates the basic components of a fire-tube boiler.

Water-Tube BoilersThe chemical processing industry also uses large industrial boilers commonly called water-tubeboilers (see Figure 6–13). A water-tube boiler consists of an upper steam-generating drum and a

150


Safety

Water In

Steam Out

Combustion Tube

Burner

Tubes

Natural Gas

Steam

Hot Combustion Gases

Figure 6–12 Fire-Tube Boiler

lower mud drum connected by three types of tubes: downcomers, risers, and steam-generatingtubes. These drums and tubes are surrounded by a furnace and a series of specially designedburners.The lower mud drum and water tubes are completely filled with water, whereas the uppersteam-generating drum is only partially full. This vapor cavity allows steam pressure to build, col-lect, and pass out of the header.Water is carried through tubes that flow near and around the burn-ers. As heat is applied to the water-generating tubes and drums, the water circulates around theboiler, down the downcomer tube, into the lower drum, and back up the riser tube and steam-generating tubes of the furnace. During normal operation, high-pressure steam is superheatedand sent to the main steam header. Lost water in the boiler is replaced by the make-up water line.Additional information about boilers can be found in Chapter 9.

6.4 Furnaces

A fired heater or furnace is a device used primarily to heat large quantities of hydrocarbons.Thesesystems are very expensive and complex and require a well-trained and dedicated staff. A processtechnician assigned to these units studies the basic components of the system, traces out eachmajor flow path, and works closely with senior technicians until he or she is qualified to operatethe equipment. Modern control instrumentation and high-tech control rooms are designed to mon-itor and control all vital processes.

151

6.4 Furnaces

Damper

Economizer Section

Mud Drum

Water In

Stack Riser

Furnace

Desuperheated Steam

Superheated Steam

Steam-Generating Drum

Steam-GeneratingTubes

Heat Air In

Downcomer

Figure 6–13 Water-Tube Boiler

Furnaces are classified as direct fired or indirect fired. Direct-fired furnaces can be identifiedby the amount of volume the combustion gases occupy inside the furnace. Fired heaters areused in many processes, including distillation, reactor processes, olefin production, and hy-drocracking. Furnaces heat raw materials to produce products like gasoline, oil, kerosene,plastic, and rubber. Fired heaters consist essentially of a battery of pipes or tubes that passthrough a firebox. These tubes run along the inside walls and roof of a furnace. The heat re-leased by the burners is transferred through the tubes and into the process fluid. The fluid re-mains in the furnace just long enough to reach operating conditions before exiting and beingshipped to the processing unit.

As with most industrial applications, fired heaters come in a wide variety of designs.

Typical furnace designs include:• Cabin—direct fired• Cylindrical—direct fired• Box—direct fired• A-frame—direct fired• Fire-tube—indirect fired

A furnace or fired heater can be classified as natural, induced, forced, or balanced draft.The pres-sure inside a warm furnace is typically lower because of buoyancy differences in the cooler out-side air. A natural-draft furnace can operate using this approach; however, when fans are used topush or pull the air through the furnace, greater heat transfer rates can be achieved. A natural-draft fired heater is severely limited in contrast to these systems.

The types of problems a fired heater or furnace system typically encounters include: flame im-pingement on tubes, coke buildup inside the tubes, hot spots inside the furnace, fuel compositionchanges, burner flameout, control-valve failure, and feed-pump failure.

Cabin-Fired HeatersThe basic components of a cabin-fired heater include a tough metal shell that surrounds a firebox,convection section, and stack. The inside of the furnace is lined with a special refractory material(brick, blocks, peep stones, gunite) that is designed to reflect heat. A battery of tubes passesthrough the convection and radiant sections and into a common insulated header that passes outof the furnace. A series of burners is located on the bottom of the furnace or on the sides. Fluidflow is carefully balanced through the tubes to prevent equipment or product damage. Airflow andoxygen content are controlled through primary, secondary, and damper adjustments. Figure 6–14illustrates the basic layout of a cabin furnace.

Cylindrical-Fired HeatersCylindrical furnaces use a small footprint and a tube-shaped firebox to transfer heat energy intoa moving liquid. Tubes are arranged in a helical or spiral pattern around the outside wall of thecylinder. The burner is traditionally located in the center so the flames do not come into contactwith the radiant tubes, refractory material, or shell. The primary source of heat transfer is radiantand convective; however, conductive heat transfer occurs as energy passes through the tubes.Cylindrical furnace designs may include a small convection section, similar to the type found ina cabin furnace.

152


The basic components of a cylindrical furnace are the same as found in a cabin furnace, with theaddition of a cone located between the radiant and convection sections. The cone evenly distrib-utes the heat as it moves up. Dampers are not typically used in this type of system. Figure 6–15shows a cylindrical furnace with a helical coil.

Box FurnacesA box furnace design is commonly used in the chemical processing industry for a variety of appli-cations and processes. This type of furnace closely resembles a box and has the same standardcomponents as a cabin furnace. The burners may be arranged on the bottom or on the sidewall;the tube arrangement depends on how the burners line up. Several simple designs are shown inFigure 6–16, along with their various operational components.

6.4 Furnaces

153

Stack

Radiant Tubes

Radiant Section Refractory

Shell

Damper

Convection Section

Convection Tubes

Charge in

Burners

Charge out

Fire Box

Fuel

Shock bank

Figure 6–14 Cabin Furnace

6.5 Reactors

A reactor is a device used to convert raw materials into useful products through chemical reac-tions. These devices combine raw materials with catalyst, gases, pressure, or heat; reactors aredesigned to operate under a variety of conditions. The shape and design of a reactor are dictatedby the application it will be used in.

Five reactor designs are commonly used in the chemical processing industry: stirred reactors,fixed-bed reactors, fluidized-bed reactors, tubular reactors, and furnace reactors. Nuclear reactorsare also used to produce steam for power generation.

Reactors are used in a variety of processes and systems:• Alkylation• Fluid coking• Fluid catalytic cracking• Chemical synthesis• Fixed- and fluidized-bed reactions• Batch and continuous processes• Hydrodesulfurization• Hydrocracking

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X X X

X X X

X X X

X X

X

Convection Tubes

Cone

Stack

Radiant Section Helical Coil

BurnerBurner

No Convection

Cylindrical All Radiant

Figure 6–15 Cylindrical Furnace

The basic components of a reactor include a shell, a heating or cooling device, two or more prod-uct inlet ports, and one outlet port. A mixer may be used to blend the materials together. Figure 6–17is an illustration of a simple mixing reactor.

A number of critical process variables associated with reactor operation include temperature,pressure, concentration of reactants, catalysts, and time. As the temperature increases, molecu-lar activity increases. Because a chemical reactor is designed to make chemical bonds, breakchemical bonds, or make and break chemical bonds, temperature is carefully controlled. By in-creasing the pressure, molecules are moved closer together. When this process is combined withheat, a higher number of molecular collisions can be achieved. The more collisions, the morechemical reactions occur within a specific amount of time. The speed at which two or more chem-icals react doubles for each 10°C increase in temperature.

The concentration of reactants in the reactor has a significant impact on how fast a reaction willoccur. Stirred reactors are designed to enhance molecular contact. Reaction time can also providethe contact that reactants need to produce the desired products. In some cases a catalyst may beused to speed up the reaction. A catalyst is a chemical that can increase or decrease a reaction

6.5 Reactors

155

Damper

Stack

ConvectionSection

ConvectionSection

RadiantSection

RadiantSection

Firebox

Firebox

Burner

BurnerBridgewall

Air Preheatfor Burner

Feed In

Feed In

Figure 6–16 Box Furnaces

rate without becoming part of the product. Catalysts can be classified as adsorption, intermediate,inhibitor, or poisoned.

Chemical reactions are classified as exothermic, endothermic, replacement, or neutralization.Exothermic reactions produce heat, whereas endothermic reactions require heat. A combustionreaction is an exothermic reaction. The reaction that causes Jell-O pudding to thicken is anendothermic reaction.

Another critical factor in reactor operation is material balance of reactants. Industrial chemistsknow exactly how much of one chemical will react with another chemical. Chemical and mechan-ical engineers carefully design reactor systems to ensure that flow rates and times are as pro-ductive as possible. When process technicians allow flow rates, pressures, temperatures, time, orany number of variables to deviate from the specifications (move off-spec), significant revenue canbe lost. Figure 6–18 shows several reactor designs.

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PIC

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LIC

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FC

FC

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Figure 6–17 Stirred Reactor

6.6 Distillation

A distillation column is a series of stills placed one on top of another. As vaporization occurs, thelighter components of the mixture move up the tower and are distributed on the various trays. Thelightest component goes out the top of the column in a vapor state and is passed over the coolingcoils of a shell-and-tube condenser. As the hot vapor comes into contact with the coils, it con-denses and is collected in the overhead accumulator. Part of this product is sent to storage; therest is returned to the tower as reflux.

Distillation is a process that separates substances from a mixture by the various boiling points ofthe substances. During the distillation process, a mixture is heated until it vaporizes; then the va-por is condensed on the trays or at various stages of the column where it is drawn off and collectedin a variety of overhead, side-stream, and bottom receivers.The condensed liquid is referred to asthe distillate; the liquid that does not vaporize in a column is called the residue.

During tower operation, raw materials are pumped to a feed tank and mixed thoroughly. Mixing isusually accomplished with a pump-around loop or a mixer. This mixture is pumped to a feed pre-heater or furnace where the temperature of the fluid mixture is brought up to operating conditions.Preheaters are usually shell-and-tube heat exchangers or fired furnaces.This preheated fluid thenenters the feed tray or section in the tower. Part of the mixture vaporizes as it enters the column,while the rest begins to drop into the lower sections of the tower.

Heat balance on the tower is maintained by a device known as a reboiler. Reboilers take suctionoff the bottom of the tower. The heaviest components of the tower are pulled into the reboiler and

6.6 Distillation

157

FIC

FIC

FIC

FIC

Feed to RX

Feed to RX

Feed to RX Feed to RXFeed to RXFIC

FIC

Fixed Bed(Converter)

Reactor

Fixed BedCatalyst

Heat In HeatIn

HeatOut

Jacketed RX

RecycleRX

Burner

Flue Gas

Direct FiredRX

EX

Pump

11

2

FIC2

Figure 6–18 Reactor Designs

stripped of smaller molecules.The stripped vapors are returned to the column and allowed to sep-arate in the tower. Distillation columns come in two basic designs: plate and packed.

Plate ColumnThe basic components of a plate distillation column include: a feed line, feed tray, rectifying orenriching section, stripping section, downcomer, reflux line, energy-balance system, overhead cool-ing system, condenser, preheater, reboiler, accumulator, feed tank, product tanks, bottom line, topline, side stream, and an advanced instrument control system. Plate columns hold trays that may bebubble-cap, valve, or sieve. Figure 6–19 shows the basic components of a plate distillation column.

Packed ColumnThe basic components of a packed distillation column include: a feed line, feed distributors, shell,hold-down grids, random or structured packing, packing support grids, bed limiters, bottom outlet,top vapor outlet, instrumentation, and an energy-balance system. Packed columns are filled withpacking to enhance vapor liquid contact. The most common types of packing are: sulzer, raschingring, flexiring, pall ring, intalox saddle, berl saddle, metal intalox, teller rosette, and mini-ring. Pack-ing can be random or structured.

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Accumulator

Condenser

Pump

Reflux

Steam In

Feed

Feed Tray

RECTIFYING

STRIPPING

Bottom

Hot Vapor

Downcomer

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TIC

LIC

LIC

AT

Hot OilIn

CTW In

CTW Out

AT

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#1

#2

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casc

casc

Figure 6–19 Distillation Column—Plate Design

Packed columns are designed for pressure drops between 0.20 and 0.60 inches of water per footof packing material. The vertical alignment of a packed distillation column is very importantbecause for each degree of inclination, 5% to 10% efficiency is lost. When the column is tilted, drysections form in the column and liquid channeling occurs. Figures 6–20 and 6–21 illustrate thebasic components of a packed column.

6.6 Distillation

159

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Support Plates

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Bottom Line

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Figure 6–20 Distillation Column—Packed Design

160


Vapor Outlet

Hatch

Liquid Feed Line

Reboiler Return

Bottom Line

XX X

XX XXXXX

X X X X XX X X X X X

XX

XX XX

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X X X X X X

Xxxxxxxxxxxxxx

Xxxxxxxxxxxxxx Bed Limiter

RandomSaddlePacking

SaddlePacking

Reflux

SightGlass

Cone Support

Cone Support

Figure 6–21 Distillation column—Packed random saddle design

6.7 Separators

One of the problems most frequently encountered in chemical process operations is that of sepa-rating two materials from a mixture or a solution. Distillation is one way of making such a separa-tion, and it is perhaps the most frequently used method. Another useful separation method isextraction. Extraction is a process for separating two materials in a mixture by introducing a thirdmaterial that will dissolve one of the first two materials but not the other. In liquid-liquid extraction,all four materials are liquids, and the mixture is separated by allowing them to separate into layers(layer out) by weight or density.

In many cases, it is impractical to separate two chemicals by distillation because the boiling pointsof the materials are too close together. In such a case it is frequently possible to find a third chem-ical that will dissolve only one of the two chemicals. In this situation, extraction is a better methodof making the separation than distillation.

Many chemicals are sensitive to heat and will degrade or decompose if raised to a temperaturehigh enough for distillation. For these chemicals, extraction, which can usually be carried out atnormal temperatures, is a practical alternative. Often, one of the materials to be separated is pres-ent only in very small amounts. It might be possible to recover such a material by distillation, butit is usually much easier and more economical to do so by extraction.

The key requirement of any commercial process is that it be economical. In situations in which sev-eral alternative means of separating two chemicals could be used, the one that is the most eco-nomical (cost-effective) is chosen. Because many relatively inexpensive solvents are available,and because the equipment required for an extraction operation is relatively simple, economic con-siderations often favor liquid-liquid extraction.

There are basically three steps in the liquid-liquid extraction process: (1) contact the solvent withthe feed solution; (2) separate the raffinate from the extract; (3) separate the solvent from the solute.Step 3, recovery of the solvent and solute, is usually done by some other process, such as distilla-tion. In liquid-liquid extraction, the feed is the original solution. The feed solution, containing thesolute (the material that will be dissolved), is fed to the lower portion of the extraction column. Thesolvent (the material that dissolves the solute) is added near the top. Because of density differ-ences, the lighter feed solution tends to rise to the top while the heavier solvent sinks to the bottom.As the two streams mix, the solvent dissolves the solute. Thus, the solute, which was originally ris-ing with the feed solution, actually reverses its direction of flow and goes out with the solvent throughthe bottom of the column. This new solution, consisting of solvent and solute, is called the extract.The other chemical in the feed stream, now free of the solute, goes out the top as the raffinate.Theraffinate and extract streams are not soluble in each other and will layer out. Figure 6–22 shows thebasic flow path and equipment and instruments associated with the separator.

The solvent must be able to dissolve the solute, but it should not be a substance that will dis-solve the raffinate or contaminate it. It also must be insoluble, so that it will layer out. The den-sity of the solvent should vary sufficiently from the density of the raffinate so that they can belayered out by the effects of gravity.The solvent must be a substance that can be separated fromthe solute. It should be inexpensive and readily available, and it should not be hazardous orcorrosive.

6.7 Separators

161

Summary

Heat exchangers transfer energy, in the form of heat, between two fluids that do not physically con-tact each other. A standard exchanger has a shell, tubes, tube sheet, shell inlet and outlet, tubeinlet and outlet, and baffles. Heat exchanger designs include simple pipe-coil, shell-and-tube,plate-and-frame, spiral, and air-cooled.

Shell-and-tube heat exchangers fall into one of eight design types: pipe-coil; double-pipe;fixed-head, single-pass; fixed-head, multipass; floating-head, multipass (U-tube); kettlereboiler; thermosyphon reboiler; and shell nomenclature. These devices can be vertically orhorizontally mounted. A typical shell-and-tube heat exchanger has a tube-side flow and a shell-side flow. Heat energy is transferred to the cooler stream as the flows pass each other in theexchanger.

The simplest type of heat exchanger is a pipe coil, in which tubes are bent to form and then sub-merged in water or sprayed with water. This process is very effective in low-volume, low-heat-loadoperations. A double-pipe heat exchanger, which has a pipe-within-a-pipe design, provides bettertemperature control.

Reboilers are energy-balance devices attached to distillation columns to help control the temper-ature. Reboilers have two basic designs: thermosyphon and kettle.

162


ATAT Pi

PiPi Pi

IP

PIC

PE

PT

IP

TIC

TE

TT IP

LE LTLT

LE LIC

IP

Separator

Feed

Light

LightHeavyLIC

TemperatureControl

Pump Pump

Fi

Fi

Pi

LCVLCV

Figure 6–22 Separator

Air-cooled heat exchangers are similar in design to shell-and-tube heat exchangers, but withoutthe shell. Air-cooled devices like car radiators remove heat generated by a combustion engine. Air-cooled heat exchangers or fin fans are designed to condense or partially condense hot vaporsfrom a distillation system. An air-cooled heat exchanger is composed of an inlet channel head anda return head, a series of plain or finned tubes, two tube sheets, and a fan.

A cooling tower is a simple device used to remove heat from water. Heat exchangers and coolingtowers typically work together to remove heat from a variety of industrial applications. A coolingtower is a box-shaped collection of multilayered slats and louvers that direct airflow and break upwater as it cascades from the top of the tower or water distribution system. The internal design ofthe tower ensures good air and water contact. Hot water transfers heat to cooler air as it passesin the tower. Sensible heat accounts for 10–20% of the heat transfer in a cooling tower; evapora-tion accomplishes 80–90% of the heat transfer.The principle of evaporation is the most critical fac-tor in cooling tower efficiency.

Cooling towers are classified by how they produce airflow and the direction the airflow takes in rela-tion to the downward flow of water. Airflow into and through a tower, which is produced naturally ormechanically, is either cross flow or counterflow. Cooling tower designs may be: (1) natural drafts,which include atmospheric (simple counterflow) and hyperbolic (chimney towers, either counterflowor cross flow); and (2) mechanical drafts, including forced draft (counterflow) and induced draft(counterflow or cross flow). The basic components of a cooling tower include a water basin, pump,and water make-up system at the base of the cooling tower. Louvers on the side of the cooling wa-ter tower admit air into the device. A fan may be used to enhance airflow through the cooling tower.

Steam generators, commonly called boilers, are used to produce steam at various pressures thatdrives turbines and provides heat to process equipment. Water-tube boilers are typically designedfor large industrial applications; fire-tube boilers are used in smaller systems and processes.

Fire-tube heaters contain the combustion gases in tubes that occupy a small percentage of theoverall volume of the heater. The basic components of a fire-tube boiler include a large shell thatsurrounds a horizontal series of tubes. A large, lower combustion tube is attached to a burner thatadmits heat into the tubes.The upper tubes transfer hot combustion gases through the system andout the stack. Airflow is closely controlled with the inlet air louvers and the stack damper. Waterlevel in the shell is maintained slightly above the tubes.

A water-tube boiler consists of an upper steam-generating drum and a lower mud drum connectedby three sets of tubes: downcomers, risers, and steam-generating tubes. A furnace surrounds andprovides heat to the drums and tubes. As heat is applied to the water-generating tubes and drums,the water circulates around the boiler, down the downcomer tube, into the mud drum, and back upthe riser tube and steam-generating tubes of the furnace.

The energy in steam can easily be transformed into mechanical or heat energy upon condensa-tion. A steam-generation system is designed to safely return cooled condensate to the boiler. Adevice called a steam trap is used to collect and transfer this material. Low points in the steam sys-tem are used to capture cooled condensate before it can damage the piping or equipment.

The chemical processing industry uses fired heaters or furnaces to heat large quantities of crudeoil and other hydrocarbons up to operating temperature for processing. As the heated feed leaves

Summary

163

the furnace, it is transported to a wide assortment of chemical processes. Fired heaters consist ofa battery of tubes that pass through a firebox. Typical furnace designs include: cabin, cylindrical,box, and A-frame (direct fired), plus fire-tube (indirect fired).

Cabin fired heaters include a tough metal shell that surrounds a firebox, convection section, andstack. Cylindrical furnaces use a tube-shaped firebox to transfer heat energy into a moving liquid.A box furnace has the same standard components as a cabin furnace.The burners can be arrangedon the bottom or on the sidewall. The tube arrangement depends on how the burners line up.

A reactor converts raw materials into useful products through chemical reactions. Reactors are de-signed to operate under a variety of conditions to combine raw materials with catalyst, gases, pres-sure, or heat.The shape and design of a reactor are dictated by the application it will be used in. Fivereactor designs are commonly used in the chemical processing industry: stirred, fixed-bed, fluidized-bed, tubular, and furnace. Nuclear reactors are also used to produce steam for power generation.

The basic components of a reactor include a shell, a heating or cooling device, two or more prod-uct inlet ports, and one outlet port. A mixer may be used to blend the materials together. A num-ber of critical process variables are associated with reactor operation, including temperature,pressure, concentration of reactants, catalysts, and time.

Distillation is a process that separates a substance from a mixture by using the boiling point of thesubstance. During the distillation process, a mixture is heated until it vaporizes, then is condensed ontrays or at various stages of the column where it is drawn off and collected in a variety of overhead,side stream, and bottom receivers. A distillation column is a series of stills stacked vertically: As va-porization occurs, the lighter components of the mixture move up the tower and are distributed on thevarious trays.The lightest component goes out the top of the column in a vapor state, is passed overthe cooling coils of a condenser, and is collected as condensate in an overhead accumulator.

Heat balance on the tower is maintained by reboilers, which take suction off the bottom of thetower. Distillation columns come in two basic designs: plate and packed.

One of the most frequently encountered problems in chemical process operations is that of sepa-rating two materials from a mixture or a solution. Distillation is the most frequently used method ofmaking such a separation. Another useful separation method is extraction, a process that separatestwo materials in a mixture by introducing a third material that will dissolve one of the first two mate-rials but not the other. In liquid-liquid extraction, all four materials are liquids, and the mixture is sep-arated by allowing them to layer out by weight or density. There are basically three steps in theliquid-liquid extraction process: (1) contact the solvent with the feed solution; (2) separate the raffi-nate from the extract; and (3) separate the solvent from the solute. The solvent must be able to dis-solve the solute but not the raffinate; must be insoluble so that it will layer out; must be separable fromthe solute; should be inexpensive and readily available; and should not be hazardous or corrosive.

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165

Chapter 6 Review Questions1. Draw a shell-and-tube heat exchanger. Label and show flows with a red pen.

2. Draw a cooling tower and label its parts. Label and show flows with a red pen.

3. Compare heat transfer in a cooling tower and a heat exchanger.

4. Draw a box furnace with an air preheater system and label its parts. Label and show flowswith a red pen.

5. Draw a water-tube boiler and label its parts. Illustrate flows with a red pen.

6. Compare water-tube and fire-tube boilers.

7. List the four basic furnace designs discussed in this chapter.

8. List four different types of fired heater burners.

9. Explain how a furnace supports the various processes found in the chemical processingindustry.

10. Compare a kettle reboiler with a thermosyphon reboiler. Explain how each works and theprimary differences between them.

11. What are the primary differences between a forced-draft and an induced-draft coolingtower?

12. List each type of heat exchanger and describe the basic operation of each type.

Process InstrumentationOneAfter studying this chapter, the student will be able to:

• List and describe the basic instruments associated with temperature, flow,level, pressure, and analytical measurement.

• Draw the basic symbols for equipment used in the chemical processingindustry.

• Identify and draw standard instrument symbols.• Draw typical line symbols used in industry.• Draw a simple process flow diagram (PFD).• Draw a complex piping and instrument drawing (P&ID).• Describe process legends and foundation, elevation, electrical, and equipment

location drawings.• Describe how interlocks and permissives work.

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Chapter 7 ● Process Instrumentation One

Key TermsElectrical drawings—graphical representations that use symbols and diagrams to depict anelectrical process system.

Elevation drawings—graphical representations showing the location of process equipment inrelation to existing structures and ground level.

Equipment location drawings—show the exact floor plan location of equipment inrelationship to the plant’s physical boundaries.

Flow diagram—a simplified diagram that uses process symbols to describe the primary flowpath through a unit.

Foundation drawings—diagrams containing concrete, wire mesh, and steel specifications thatidentify width, depth, and thickness of footings, support beams, and foundation.

Legends—used to describe symbol meanings, abbreviations, prefixes, and other specializedequipment; function like the key of a map.

Piping and instrumentation drawing (P&ID)—a complex diagram that uses process symbolsto describe a process unit.

Process equipment—piping, tanks, valves, pumps, compressors, steam turbines, heatexchangers, cooling towers, furnaces, boilers, reactors, distillation towers, and so on; all theprimary machines and devices used in a process.

Process flow diagram (PFD)—chart used to outline or explain the complex flow, equipment,instrumentation, electronics, elevations, footings, and foundations that exist in a process unit.

Process instrumentation—transmitters, controllers, transducers, primary elements andsensors, and so on; all the measurement and control devices used to monitor and controla process.

Process symbols—images that graphically depict process equipment, piping, andinstrumentation.

7.1 Introduction to Process Instruments

The primary variables that a process technician works with and controls are pressure, tempera-ture, flow, level, and analytical or composition. Various instruments are designed to help facilitatethis critical aspect of process work. Some of these instruments include computers, gauges,recorders, transmitters, controllers, transducers, primary elements and sensors, switches, andcontrol valves.

Process technicians use instruments to control complex industrial processes. Thirty years ago,most operators controlled the processes in their plant manually. This type of process was “valveintensive”; in other words, it required the technician to open and close line-ups manually. Basicprocess instruments have improved as the era of automation has been ushered in. A singleprocess technician can monitor and control a much larger process from a single control center.

PressureThe scientific principles associated with pressure are invaluable in modern chemical processing,and they are used and applied constantly. (In Chapter 4, we discussed how pressure is equal toforce divided by area.) A variety of instruments is used to measure and indicate pressure. Someof the more common ones include pressure indicators that use manometers, bourdon tubes, orhelical, spiral, or bellows-shaped tubes. The movement created when these devices expand orcontract is used to indicate pressure. Pressure transmitters are used with control loops that aredesigned to control the pressure in a specific system. They use a flexible diaphragm to measurechanges in pressure. Pressure gauges are typically located on the suction and discharge of apump, on the inlet and outlet of a heat exchanger, on the bottom of a tank, or on a compressorsystem. Figure 7–1 illustrates the various components of these different devices.

Operators frequently walk through the unit and review various pressure gauges. Consoleoperators closely monitor pressure variables and respond to any alarms. Pressure readings aretypically measured in psia or psig.


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Figure 7–1 Pressure Devices

TemperatureDuring routine operations, the temperature of each process is carefully controlled by a small groupof instruments. Common examples of these instruments include thermocouples, RTDs, capillarytubing, thermometers, thermal bulbs, thermistors, and bimetallic detectors. Figure 7–2 showsexamples of these different devices. Temperature changes are measured in Fahrenheit, Rankine,Celsius, and/or Kelvin. Water freezes at 32 degrees Fahrenheit and 0 degrees Celsius andboils at 212 degrees Fahrenheit and 100 degrees Celsius. Rankine and Kelvin are absolutemeasurement scales. Degrees Kelvin � degrees Celsius � 273, and degrees Rankine � degreesFahrenheit � 459.7.

Thermocouples are composed of two dissimilar metals that expand at different rates. This type ofdevice converts heat to electricity; that is, a thermocouple generates an electric signal in responseto heat intensity. This signal can be converted into a temperature measurement.

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THERMOCOUPLE

FR C K212°F 100°C 373672

Water boils

Water freezes Water freezes

32°F492 0°C 273

-460°F0 -273°C 0

ABSOLUTE ZERO

°°K

K

K

R

R

R

KelvinCelsiusFahrenheitRankin

0

200

400C

xxxx

ThermalBulb

Capillary Tubing

0

200

400C

BimetallicThermally Reactive MetalThermally Stable Metal

Bonding Metal

Figure 7–2 Temperature Measurement Devices

LevelFor level measurement, technicians use sight glasses, floats, displacement devices, conductivityprobes, and differential pressure transmitters. Sight glasses are attached to the process equipmentor tank being measured. An open and vented sight glass allows the liquid level in the tank to rise toits correct level. This allows a technician to visually check the level under any operating condition.Floats and displacement devices can be attached to mechanical arms, rods, tapes, or chains thatmove indicators. These same devices can also be attached to transmitters and can relay an elec-tric, electronic, or pneumatic signal. Conductivity probes can be used as high- and low-level alarms.These devices use electricity to complete or break a circuit. Differential pressure (DP) transmittersare used to detect pressure changes in liquid level. Because the height (amount) of a liquid is di-rectly proportional to the pressure exerted by the liquid, a DP transmitter can accurately calculateand transmit this signal to a distant point. Figure 7–3 illustrates each of these devices.

In addition to the level-measurement devices illustrated in Figure 7–3, there are air bubblersystems for level detection, ultrasonic level detectors, and radiation level detectors. Ultrasonic and


171

0% 100 50%

Level Controller

Transmitter

Differential Pressure

Transmitter

I P

Transducer

Control Valve

Sight glass

Displacer

Rod

TK-202

High Low

0% 100 50%

I P

Transducer

Fail Open

Fail Open

LIC 202

High Level Alarm

Capacitance Probe

Figure 7–3 Level Measurement

radiation detectors are classified as noncontacting. Ultrasonic detectors emit a pulsed frequencysignal from the top of the vessel down. This standardized wave velocity allows the device to actu-ally determine how much material is not in the vessel.The detector must be positioned so the pulsewave strikes the perpendicular surface of the liquid. Radiation level detectors have two basic parts:a radiation transmitter and a radiation detector.These devices are positioned on opposite sides ofthe vessel. When a gamma wave is emitted from the transmitter, it is absorbed by the liquid and acomparison is made between the energy emitted and the energy received.

FlowFlow rate is typically measured in gallons per minute (gpm) or gallons per hour (gph). A variety ofdevices can be used to accomplish flow measurement. Common examples of flow measurementdevices are orifice plates, venturi nozzles, nutating disc meters, turbine flow meters, oval gearmeters, rotameters, pitot tubes, weir and flume, and flow transmitters. Figure 7–4 shows a fewexamples of flow-measurement devices.

172


0 50 25

I P

Control Valve

10

20

30

40

50

60

70

80

90

2 3 4 79

GPM

Flow In

Flow In

Flow In

Rotameter

Oval Gear Meter

Turbine Flow Meter

Flow Controller

Orifice Plate

Transducer

Motor

Figure 7–4 Flow Measurement

Orifice plates are flat plates with holes that are typically smaller than the inside diameter of thepipe. The intent is to place the device between two flanges and restrict flow so that an artificialhigh- and low-pressure zone is created on each side of the orifice. A transmitter is used to calcu-late the differential and calculate a flow rate. The venturi flow nozzle uses the same principle asthe orifice plate.

Rotameters have a glass tube with a flow element trapped between the measurement grid. Thistype of device provides direct contact between the measurement element and the fluid. Flow typ-ically enters at the bottom of the rotameter and lifts the flow element. Oval gear meters and tur-bine flow meters displace a specific amount of liquid on each rotation. This is used to calculatetotal flow rate through the system. Pitot tubes are positioned perpendicular to flow. As the liquidenters the tube, precision-machined sensing vents determine flow rate.

AnalyticalAnalytical variables are associated with devices designed to measure the composition of asubstance. For example, process technicians use analyzers to determine the percentage of asubstance in a process stream. Analyzers come in a variety of shapes and designs, and can mea-sure the concentration of a specific chemical or element. Other examples of analytical process vari-ables include pH or parts per million (ppm).These variables are frequently tracked on a cooling watersystem. Plastic plant technicians check for melt flow, color, and the concentration of special additives.Figure 7–5 shows an assortment of basic instruments used in the chemical processing industry.

7.2 Symbols and Diagrams

One of the more difficult tasks a new process technician is faced with is memorizing the hundredsof symbols and diagrams associated with the process industry. These process symbols form the


173

0 300150FAHRENHEIT

TEMPERATURE TRANSMITTER

05 10

1520

PSIG

Pressure Gauge

Control Valve

Recorder Controller

TemperatureController

0

200

400

C

Thermocouple

H L

P CellTransmitter

Orifice

Figure 7–5 Basic Instruments

written flow language necessary for understanding how a specific process operates. This learningprocess should be taken one step at a time, building from simple symbols to more complex processes.Learning and recognizing these symbols is the key to moving to the next step of a very good career.

Symbols and diagrams can be broken down into four primary parts:• Process equipment symbols• Process instrument symbols• Process flow diagrams (PFDs)• Piping and instrumentation drawings (P&IDs)

Symbols and diagrams have been developed for most pieces of industrial equipment, process flows,and instrumentation.The symbols covered in this chapter include those typically used with valves, pip-ing, tanks, pumps, compressors, steam turbines, motors, heat exchangers, cooling towers, furnaces,boilers, distillation columns, and reactors. Figure 7–6 shows many of the basic symbols for valves.

174


Globe

Gate

Three-WayValve

Bleeder Bleeder

PneumaticallyOperated

ManuallyOperated

Gauge Orifice

SAFETY (Gases)

Butterfly

Ball

SolenoidCLOSED

S

Rotameter

Four-WayValve

Needle

Angle

Plug

Diaphragm

Butterfly

Check

M

Pneumatic Motor Hydraulic

M H

M H M

Ball

H M

Pneumatic Motor HydraulicMotor

Motor orHydraulic

Pneumatic

Motor

M

GATE VALVES

GLOBE VALVES

BALL VALVES

BUTTERFLY VALVES

DIAPHRAGM VALVES CHECK VALVES

PLUG VALVES

Motor orHydraulic

Motor orHydraulic

Plug

Pinch Valve

Stop Check

Knife Valve

RELIEF (Liquids)

Figure 7–6 Valve Symbols

Piping SymbolsEach plant will have a file of its standardized piping symbols. Process technicians should carefullyreview these piping symbols for major and minor flows, and for electric, pneumatic, capillary, hy-draulic, and future equipment.The major flow path through a unit illustrates the critical areas a newtechnician should concentrate on. Some of the devices used in piping are strainers, filters, flanges,spool pieces, and steam traps. A variety of piping symbols can be found in Figure 7–7.

Pumps and Tank SymbolsPumps and tanks come in a variety of designs and shapes. Some of these designs includecentrifugal and positive displacement pumps. Centrifugal pumps can be mounted vertically andhorizontally in the field. Special symbols are used to distinguish each of these. A common symbol


175

Y-Type Strainer

Duplex Strainer

Basket Strainer

D Detonation Arrestor

F Flame Arrestor

T Steam Trap

S In-Line Silencer

DS Desuperheater

Ejector / Eductor

Exhaust Head

S Vent Silencer

RSRemovable Spool

Flexible Hose

Expansion Joint

XXX Breather

Vent Cover

In-Line Mixer

Diverter Valve

Rotary Valve

Pulsation Dampener

Flange

Minor Process

Pneumatic

Hydraulic

Capillary Tubing

Electromagnetic, SonicOptical, Nuclear

X X X X

L L L

Major Process

Future Equipment

Connecting Line

Nonconnecting Line

Nonconnecting Line

Jacketed or Double ContainmentMechanical Link

Software or Data Link• • • •

Electric

Figure 7–7 Piping Symbols

used to describe a positive displacement pump looks like a set of stairs. This illustrates how pres-sure builds on each rotation or stroke of the flow elements. Positive displacement pumps can beclassified as rotary or reciprocating. Special symbols are used to describe each of these devices,including screw pumps, gear pumps, and reciprocating pumps.

A variety of symbols are used to illustrate the different type of tanks and vessels found in the chem-ical processing industry, including bins, drums, and dome, cone, open-top, floating-roof, andspherical tanks. Process symbols are designed to graphically display the vessel as it appears inthe field. Common pump and tank symbols are shown in Figure 7–8.

Compressor and Pump SymbolsCompressors and pumps share a common set of operating principles. The dynamic and positivedisplacement families share common categories. Therefore, the symbols for compressors mayclosely resemble those for pumps. In most cases, the symbol is slightly larger in the compressorsymbol file. For a multistage, centrifugal compressor, the symbol clearly describes how the gas is

176


Vacuum Pump

CENTRIFUGAL PUMPS

Bin Tank

Drum

GearPump

Vertical

Screw Pump

POSITIVE DISPLACEMENT PUMPS

Positive Displacement

Dome RoofTank

Open TopTank

Tank

Sphere Onion Tank

STORAGE SYMBOLS

Progressive Cavity

PositiveDisplacement

Screw Pump

Vertical CanPump

Reciprocating Pump

Sump Pump

Horizontal

Vertical

Vertical


Cone RoofTank

Double WallTank

External FloatingRoof

Figure 7–8 Pump and Tank Symbols

compressed prior to being released. This is in sharp contrast to the steam turbine symbol, whichillustrates the opposite effect as the steam expands while passing over the rotor.

Modern piping and instrumentation drawings show the motor symbol connected to the driven equip-ment. This equipment may be a pump, compressor, mixer, fan, conveyor, or generator. Figure 7–9illustrates the standardized symbols for compressors, steam turbines, and motors.

Heat Exchanger and Cooling Tower SymbolsHeat exchangers and cooling towers are two types of industrial equipment that share a uniquerelationship. A heat exchanger is a device used to transfer heat energy between two process flows.The cooling tower performs a similar function; however, cooling towers and heat exchangers op-erate according to different scientific principles. Heat exchangers transfer heat energy throughconductive and convective heat transfer methods, whereas cooling towers transfer heat energy tothe outside air through the principle of evaporation. Figures 7–10 and 7–11 illustrate the standardsymbols used for heat exchangers and cooling towers.

The symbol for a heat exchanger clearly illustrates the flows through the device. It is important fora process technician to be able to see the shell inlet and outlet and the tube inlet and outlet flow


177

STEAM TURBINES

Doubleflow Turbine

RotaryCompressor

ReciprocatingCompressor

RotoryCompressor & Silencers

CENTRIFUGAL COMPRESSORS

Centrifugal Compressor

Centrifugal Compressor(Turbine Driven)

POSITIVE DISPLACEMENT COMPRESSORS

Rotary ScrewCompressor

PositiveDisplacement

Blower

Liquid RingVacuumCentrifugal

Blower

CentrifugalCompressor

Reciprocating Compressor

Motor

Turbine Driver

Diesel Motor

Agitator or Mixer

Axial Compressor

T

Figure 7–9 Compressor, Steam Turbine, and Motor Symbols

178


Plate and FrameHeat Exchanger

Air-Cooled Exchanger(Louvers Optional)

Double-PipeHeat Exchanger

CC

Spiral Heat Exchanger

Shell & Tube Heat Exchanger

Single PassHeat Exchanger

U-TubeHeat Exchanger

Hairpin Exchanger

CondenserHeater

Reboiler

Figure 7–10 Heat Exchanger Symbols

INDUCED DRAFTCross Flow FORCED DRAFT

Counterflow

HYPERBOLICChimney Tower

NATURAL DRAFTCounterflow

Figure 7–11 Cooling-Tower Symbols

paths. A heat exchanger with an arrow drawn through the body illustrates whether the device isbeing used to heat or cool a product. The downward direction indicates heating; the upwarddirection illustrates cooling.

Heat exchanger types include shell-and-tube, plate-and-frame, spiral, and air-cooled. Shell-and-tube heat exchangers are the most common and complex. For example, a shell-and-tube heat ex-changer can be drawn as a single-pass, fixed-head, multipass, double-pipe with fins, U-tube, orkettle reboiler. The symbol for each device is unique and helps identify how the device is beingused and how to safely operate it. Spiral and plate-and-frame heat exchangers are widely used;however, they are not as common as shell-and-tube devices. Air-cooled heat exchangers are of-ten referred to as fin fans. Actually, the tubes can be plain or finned depending on system re-quirements. Finned tubes transfer heat more effectively. Devices of this sort are used to condenseoverhead vapors from a distillation system.The symbols used for these devices distinguish the dif-ferences between them.

The symbol for a cooling tower is designed to resemble the actual device in the process unit.Cooled product flows out of the bottom of the tower and to the processing units, while hot waterreturns to a point located above the fill. The primary purpose of a cooling tower is to cool water. Acooling tower has a box or rectangular shape that rests on a concrete water basin. It is filled witha matrix of boards or slats that are positioned to break up the downward flow of water. Air passesbetween the downward flow of water and out the top as the air rises naturally or is drawn in me-chanically.The primary mechanism of heat transfer is through evaporation.This principle accountsfor 80% to 90% of the cooling process. (Sensible heat accounts for the rest.) A pump takes suc-tion off the basin, sends it to a heat exchanger system, and then returns it to the cooling tower. Hotwater enters the top of the cooling tower and is distributed using the water distribution system. Amechanical fan may be used to draw in or expel air through a set of air louvers located on the sidesof the cooling tower. The water basin has a water make-up system designed to maintain waterlevel. Periodically, the water in the basin is blown down to reduce suspended solids in the processstream.

Boiler and Furnace SymbolsA steam generator or boiler is used by industry to boil water and produce high-, medium-, or low-pressure steam. The symbol for a boiler closely resembles that for a large water-tube boiler. Boil-ers are composed of an upper steam-generating drum, a lower mud drum, downcomer tubes, risertubes, steam-generating tubes, an economizer section, a water make-up system, a stack, a fan,and burners. All of these devices are neatly enclosed inside a refractory-lined shell designed toreflect heat back into the furnace.

Boilers can be classified as water tube (direct fired) or fire tube (indirect fired), depending on theinternal design of the device. Fire-tube boilers are used in small commercial operations andtypically do not have the range or capacity of water-tube boilers.

A fired heater or furnace is used to heat large quantities of hydrocarbons for industrial use in adistillation system or reactor. Fired heaters are characterized by three basic designs: cabin, cylin-drical, and box. The basic components of a furnace include shell, refractory lining, burners, radi-ant tubes, convective tubes, damper, stack, and firebox. Air and fuel are proportionally balancedas temperatures in the furnace are held constant. Figure 7–12 shows the two standard symbolsused for a fired heater or furnace and a boiler.


179

180


Furnace Boiler

Figure 7–12 Boiler and Furnace Symbols

Distillation SymbolsOn a typical flow diagram, distillation columns, reactors, boilers, and furnaces are drawn as theyvisually appear in the plant. If a proprietary process includes several types of equipment not typicallyfound on a standard symbol file, the designer will draw the device as it visually appears in the unit.

Distillation is a process that separates the components in a mixture by boiling point. At the heart ofa distillation system is the column. Distillation columns come in two basic designs: plate and packed.Flow arrangements vary from process to process. The symbols allow the technician to identify pri-mary and secondary flow paths. The two standard symbols for distillation columns are shown inFigure 7–13. A distillation system is a complex arrangement of equipment and instruments. In mostcases, all of the equipment covered in this text could be found in service within a distillation system.

The symbol used on a diagram for a plate column should indicate the type of tray used in the sys-tem: bubble-cap, valve, or sieve. The first distillation column was invented in 1917. Today, a num-ber of modifications allow modern process technicians to operate much more efficiently. Thedesign, however, still includes the original still-on-top-of-a-still approach.The basic components ofa plate distillation column are a feed line; feed tray; stripping section below the feed line; enrichingor rectifying section above the feed line; overhead vapor outlet, side-stream outlet, and bottom out-let; reboiler; instrumentation for level, temperature, flow, pressure, and composition control; outershell; and a top reflux line.

Packed columns are designed to enhance vapor-liquid contact as hot vapors rise up the column andliquids condense and drop down the column. In this type of system, packing is used to create thesurface area for this contact, as liquids and vapors compete for access through the same passages.Various packing designs include saddle, ring, and sulzer packing.The basic components of a packedcolumn include a feed line; structured or unstructured packing; liquid distributor; shell; overhead va-por outlet, side-stream outlet, and bottom outlet; packing supports; bed limiters; reboiler; instrumen-tation for level, temperature, flow, pressure, and composition control; and a top reflux line.

Reactor SymbolsModern process manufacturing utilizes all of our advanced knowledge about chemistry andchemical reactions to form and create new products.The primary people involved in this industry

are chemical engineers, chemists, mechanical engineers, and process chemical technicians.While much of the chemistry is transparent to the technician, understanding the complexconcepts is important to being able to operate modern reactor systems. There are six basicreactor designs: stirred-tank, fixed-bed, fluidized-bed, tubular, furnace, and nuclear.The primaryreaction variables include temperature, pressure, flow, concentration of reactants, catalysts, andtime. Chemical reactions may be exothermic (produce heat), endothermic (require heat),replacement, and neutralization.

Reactors are stationary vessels that are classified as batch, semi-batch, or continuous. Somereactors use mixers to blend the individual components. Reactor design depends on the type ofservice the reactor will be used in. Some of the reactor processes (among many others) includealkylation, catcracking, hydrodesulfurization, hydrocracking, fluid coking, reforming, polyethylene,and mixed-xylene. Figure 7–14 shows the standard symbols for reactors.


181

PLATE TOWERBubble-Cap, Sieve, Valve

PACKED TOWERSaddle, Ring, Sulzer, Rosette

Single Pass

Chimney

Two Pass

Draw Off

Generic Tray

Demister

Spray Nozzle

Packed Section

Manway

Vortex Breaker

Figure 7–13 Distillation Symbols

7.3 Process Diagrams

Process diagrams can be broken down into two major categories: process flow diagrams andpiping and instrumentation drawings. A flow diagram is a simplified illustration that uses processsymbols to describe the primary flow path through a unit. A piping and instrumentation drawing isa complex diagram that uses process symbols to describe an entire process unit.

Process flow diagrams (PFDs) are used to outline or explain the complex flows, equipment, in-strumentation, electronics, elevations, footings, and foundations that exist in a process unit. Newtechnicians are required to study a simple flow diagram of their assigned unit. Process flow dia-grams typically include the major equipment and piping path the process takes through the unit.As operators learn more about symbols and diagrams, they graduate to the much more complexpiping and instrumentation drawings.

Some symbols are common between plants, whereas others change depending on the company.In other words, two different symbols may be used to identify a centrifugal pump or a valve, for ex-ample. Some standardization of process symbols and diagrams is taking place, but the processtechnician must learn what symbols his or her employer uses. The symbols shown in this chapterreflect a wide variety of petrochemical and refinery operations.

182


Hydrocracking Hydrodesulfurization Reformer

Fluid CatalyticCracking

Fluid Coking TubularReactor

FluidizedReactor

Mixing Reactor Alkylation

Figure 7–14 Reactor Symbols

A piping and instrumentation drawing (P&ID) is a complex representation of the various unitsfound in a plant. While the simple process flow diagram is typically used to describe the primaryflow path through a unit, a P&ID, like a road map, can show intricate details of a unit that cannoteasily be noticed during a walk-through. Process technicians are expected to be able to read sim-ple flow diagrams within hours of starting their initial training. Technicians will graduate to readingand using complex P&IDs over the course of their training.

To read a P&ID, you need to understand process equipment, process instrumentation, andprocess technology. Some of this equipment includes piping, valves, pumps, tanks, compressors,steam turbines, process instrumentation, heat exchangers, cooling towers, furnaces, boilers, re-actors, and distillation columns.The next step in using a P&ID is to memorize your plant’s processsymbol list. This information can be found on the process legend. Process and instrumentationdrawings have a variety of elements, including flow diagrams, equipment layouts, elevation plans,electrical layouts, title blocks and legends, and footings and foundation drawings.

Figure 7–15 shows the basic relationships and flow paths found in a process unit. It is easier to un-derstand a simple flow diagram if it is broken down into four different sections: feed, preheating, theprocess, and the final products (see Figure 7–16).This simple left-to-right approach allows a technicianto identify where the process starts and where it will eventually end.The feed section includes the feed

7.3 Process Diagrams

183

Furnace

Feed Tank

Bottom Tank

Boiler

Cooling Tower

Reactors

ProductTank

2

ProductTank

1

Vacuum Pump

Column

Drum

Figure 7–15 Process Flow Diagram (PFD)

184


Furnace

Boiler

Cooling Tower

Column

Feed Section Preheating The Process Products

MixingReactor

EX-1

TK-2

TK3

TK4

TK5

TK6

TK-1

BlendingTank

Figure 7–16 Four-Section Flow Diagram

tanks, mixers, piping, and valves. In the second section/step, the process flow is gradually heated upfor processing; this section includes heat exchangers and furnaces. In the third section, the process isdetailed.The process area is a complex collection of equipment pieces that work together in a system.The process is designed to create products that will be sent to the final section.Typical process-sectioncomponents are distillation and reaction.The final section shows the final product(s).

Instrumentation symbols are shown on a P&ID as a circle, inside which information is included thattells the process technician what type of instrument is represented. Figure 7–17 shows examplesof typical instrument symbols.

7.4 Interlocks and Permissives

An interlock is a device designed to prevent damage to equipment and personnel. It accomplishesthis by stopping or preventing the start of certain equipment functions unless a preset condition hasbeen met.There are two types of interlocks: softwire and hardwire. Softwire interlocks are containedwithin the logic of the control computer software. Hardwire interlocks are a physical arrangement. Ahardwire interlock usually involves electrical relays that operate independently of the control com-puter. In many cases they run side by side with the computer interlocks. However, hardwire interlockscannot be bypassed. They must be satisfied before the process they are part of can take place.

A permissive is a special type of interlock that controls a set of conditions that must be satisfiedbefore a piece of equipment can be started. Permissives deal with start-up items, whereas hardwireinterlocks deal with shutdown items. A permissive is an interlock controlled by the distributivecontrol system (DCS). This type of interlock will not necessarily shut down the equipment if one ormore of its conditions are not met. It will, however, keep the equipment from starting up.

7.4 Interlocks and Permissives

185

Flow Indicator

Flow Transmitter

Flow Recorder

Pressure Indicator

Pressure Transmitter

Fi

FT

FR

Pi

PT

Temp Indicator

Temp Transmitter

Temp Recorder

Level Indicator

Level Transmitter

Level Controller

Ti

TT

TR

Li

LT

LC

F I C

55

Variable beingmeasured

Remote location(board mounted)Control loop

Instrument

Remote location(behind control panel)

Field mounted

LR Level Recorder

TC Temp. Controller

PR Pressure Recorder

Pressure ControllerPC

65 55

5565

65 55

Flow ControllerFC

PIC

PRC

LA

105

40

25

IP

Transducer

Pressure IndicatingController

Pressure RecordingController

Level Alarm

FE Flow Element

TE TemperatureElement

LG Level Gauge

AT Analyzer Transmitter

What it does

Fi

FT

FA25

Flow Alarm (Remote Location)

FlumeVortex Meter

Sight FlowIndicator

Turbine Meter

Venturi

Duplex Strainer

Basket Strainer

Weir

Target

Positive Displacement

FE

FS*

FT

FO

MagneticM

Flow Nozzle

RestrictionOrifice

Flow ConditioningDevices

Pitot Tube

Averaging Pitot Tube

Wedge Meter

Orifice

In-Line Flow Element withIntegral Transmitter. Ex. Mass,Coriolis, Thermal, Int. Orifice

In-Line FlowElement

Ultrasonic

Flow Switch* = H/L

Rotameter

PSID Pounds Per SquareInch Differential

PSIV Pounds Per SquareInch Vacuum

PSIA Pounds Per SquareInch Absolute

PIC

PIC

Press. Indicating Controller DCS (Remote Loc.)

Press. Indicating Controller PLC (Remote Loc.)

PA25

Press. Alarm (Remote Location)

PSIGPounds Per Square

Inch Gauge

PG Press. GaugePE

PS*

PTIn-Line PressureElement

Pressure Switch* = H/L

LIC

LIC

Level Indicating Controller DCS (Remote Loc.)

Level Indicating Controller PLC (Remote Loc.)

15

4

LAH2

Level Alarm High (Remote Location)

LAL2

Level Alarm Low (Remote Location)

LS* Level Switch* = H/L

ThermowellTW

EP

Transducer(Converter)

Elec to Pneumatic)

TYTransducer(Converter)

101 101

101

AIC

AE

AS*AT

Analytical Switch* = H/L

Figure 7–17 Instrument Symbols

186


F-105

TK-10

TK-16

B-105

CT-105

RX-105C-105

FCV

I/P

TT TC

I/P

PT

PC

PCV

I/P

LT

LC

I/P

I/PLT LC

TE TT TC I/P

P-10

P-11

RX-106

P-12

V-1

D-105

TK-12

TK-14

P-13

P-14

V-2 V-3

V-4

V-5

V-6

EX-105

V-7

P-15

FT

FC

Figure 7–18 Piping and Instrumentation Drawing (P&ID)

7.5 P&ID Components

The piping and instrumentation drawing includes a graphic representation of the equipment, pip-ing, and instrumentation (see Figure 7–18). Modern process control is vividly illustrated in this typeof drawing. Process technicians can look at their process and see how the engineering depart-ment has automated their unit. Pressure, temperature, flow, level, and analytical control loops areall included on the unit P&ID. The basic components of a piping and instrumentation drawing arethe process legend, foundation, elevation, electrical, equipment location drawings, simple flowdiagram, piping, and instrumentation.

Simple Flow DiagramA simple flow diagram provides a quick snapshot or overview of the operating unit. Flow diagramsinclude all primary equipment, flows, and numbers. A technician can use this document to tracethe primary flow of chemicals through the unit. Secondary or minor flows are not included.Complex control loops and instrumentation are not included. The flow diagram is used for visitorinformation and new employee training.

Process LegendsThe process legend (see Figure 7–19) provides the information needed to interpret and read theP&ID. Process legends are found at the front of the P&ID. The legend includes information aboutpiping, instrument, and equipment symbols; abbreviations; title block; drawing number; revisionnumber; approvals; and company prefixes. At present, symbol and diagram standardization is notcomplete or uniformly accepted. Many companies use their own symbols file for display on unitdrawings. Unique and unusual equipment will also require a modified symbols file.

7.5 P&ID Components

187

GlobeValve

GateValve

Three-WayValve

BleederValves

ManuallyOperated

Valve

Gauge

Orifice

SAFETY (Gases)

Ball

Solenoid ValveCLOSED

S

Rotameter

Four-WayValve

Angle Plug

Diaphragm

Butterfly

CheckValve

ReliefValve

Pneumatic

Pneumatic

Pinch Valve

Stop Check

Knife Valve INDUCED DRAFTCross Flow

NATURAL DRAFTCounterflow

FURNACE

BOILER

VacuumPump

Centrifugal

Drum

GearPump Positive

Displacement

Dome RoofTank

Sphere


Progressive Cavity

Screw Pump

ReciprocatingPump

Sump Pump

Horizontal

Vertical


Cone RoofTank

Plate and FrameHeat Exchanger

Air Cooled Exchanger(Louvers Optional)

Double-PipeHeat Exchanger

CC

Spiral Heat Exchanger

Condenser

Heater

SinglePass

Chimney

Two Pass

Draw Off

GenericTray

Demister

SprayNozzle

PackedSection

Manway

VortexBreaker

VALVE SYMBOLS

EQUIPMENT SYMBOLS

Minor Process

Pneumatic

Hydraulic

Capillary Tubing

Electromagnetic, SonicOptical, Nuclear

X X X X

L L L

Major ProcessFuture Equipment

Connecting Line

Nonconnecting Line

Nonconnecting Line

Jacketed or Double Containment

Mechanical Link

Software or Data Link

• • • •

Electric

Flow Indicator

Flow Transmitter

Flow Recorder

Pressure Indicator

Pressure Transmitter

FI

FT

FR

PI

PT

Temp Indicator

Temp Transmitter

Temp Recorder

Level Indicator

Level Transmitter

Level Controller

TI

TT

TR

LI

LT

LC

LR Level Recorder

TC Temp. Controller

PR Pressure Recorder

Pressure ControllerPC

65 55

5565

65 55

Flow ControllerFC

PIC

PRC

LA

105

40

25

IP

Transducer

Pressure IndicatingController

Pressure RecordingController

Level Alarm

FE Flow Element

TE Temperature Element

LG Level Gauge

AT Analyzer Transmitter

APPROVED

GENERAL LEGEND

DRAWING NUMBER

REVISION 1

PC

E

DATE 10-6-99

PAGE 1 OF 30

OO6543

DISTILLATION UNIT

LINE SYMBOLSEQUIPMENT CONT.

INSTRUMENT SYMBOLS

PREFIXES ABBREVIATIONSCW- cooling waterMU- make-upFW- feed waterSE- sewer

RX- reactorUT- utilitiesCA- chemical additionIA- instrument air

D- drumC- columnCT- cooling tower

TK-tankF- furnaceEX- exchanger

P- pumpV- valve

Figure 7–19 Process Legend

188


N

WE

S

64'-0"

28'-0"

28'-0"

6'-0"

8'-0"

10'-0"

6-8-10 Method

2' x 64' x 18"load bearing

beam

18"4"

12"

Estimating Materials: cu yds = width x length x thickness

27

Remesh Remeshover plastic

Remesh

Rebar in all beams

32'-0"

90

Figure 7–20 Foundation

FoundationFoundation drawings (see Figure 7–20) are used by the construction crew pouring the footers,beams, and foundation. Concrete and steel specifications are designed to support equipment, in-tegrate underground piping, and provide support for exterior and interior walls. Foundation draw-ings are typically not used by process technicians; however, they are useful when questions ariseabout piping that disappears under the ground and when new equipment is added.

ElevationElevation drawings are graphical representations that show the location of process equipment inrelation to existing structures and ground level. In a multistory structure, the elevation drawing pro-vides the technician with information about equipment operation and location.The drawing closelyresembles a process that removes the outside wall of the building and draws the exposedequipment. This information is important for making rounds, doing equipment checks, developingchecklists, catching samples, and performing start-ups and shutdowns. The elevation plan in Figure 7–21 illustrates equipment and structure locations.

ElectricalElectrical drawings include symbols and diagrams that depict an electrical process system. Elec-trical drawings show unit electricians where power transmission lines run and places where it isstepped down or up for operational purposes. A complex P&ID is designed to be used by a varietyof crafts.The primary users of the document after plant start-up are process technicians, instrumentand electrical, mechanical, safety, and engineering.

7.5 P&ID Components

189

EL 16'-0"

EL 28'-0"

EL 40'-0

TK-105

RX-105

TK-200

TK-300

RX-106

RX-300 C-300

D-56

Figure 7–21 Elevation

A process technician typically traces power to the unit from a motor control center (MCC).The pri-mary components of an electrical system are the MCC, motors, transformers, breakers, fuses,switch gears, starters, and switches. Specific safety rules apply to the operation of electrical sys-tems. The primary safety system is the isolation of hazardous energy through lock-out/tag-outmeasures. Process technicians are required to have training in this area. Figure 7–22 shows thebasic symbols and flow path associated with an electrical drawing. Electrical lines are typically runin cable trays to switches, motors, ammeters, substations, and control rooms.

A transformer is a device used by industry to convert high voltage to low voltage. Problems withtransformers are always handled by the electrical department. Electrical breakers are designedto interrupt current flow if design conditions are exceeded. Breakers are not switches and shouldnot be turned on or off. If a tripping problem occurs, the technician should call for an electrician.Fuses are devices designed to protect equipment from excess current. A thin strip of metal withinthe fuse will melt if design specifications are exceeded. During operational rounds, technicianscheck the ammeters inside the MCC for current flow to their electrical systems. Voltmeters, elec-trical devices used to monitor voltage in an electrical system, are also checked during routinerounds.

Equipment Location DrawingsEquipment location drawings show the exact floor plan location of equipment in relationship tothe plant’s physical boundaries. Figure 7–23 illustrates this layout. Location drawings provide ben-efits similar to those of elevation drawings. The entire P&ID provides a three-dimensional look atthe unit.

190


V Voltmeter—measures voltage Vs Voltmeter Switch

27

Power Transformer—reduces high voltage

Potential Transforming Symbol

Under Voltage Relay

M Motor MCC Motor Control Center

Switch

Fuse

Circuit Breaker—a protective devicethat interrupts current flow through anelectric circuit

A

As

50

51

Ammeter—measures electric current Ammeter Switch

Transformer Overcurrent Relay (Instantaneous)

Transformer Overcurrent Relay (Time delay)

Motor Circuit Contacts

Current Transformer—reduces high voltage to instrumentation

BOILERSteamTurbine

Generator

69,000 Volts

69 kV

13,200 V13,800 V2,300 V

13.2 kV13.8 kV2.3 kV

OnOff

Motor

2.3 kV or480 Volts

51

MAINTRANSFORMER

As

A

27

V

Vs

MCC #1

480 V BUS MAIN POWER DISTRIBUTION

ELECTRIC POWER PLANT

M M

MotorStarter

MotorStarter

Figure 7–22 Electrical

Summary

191

Summary

The primary variables that a process technician works with and controls include pressure, tempera-ture, flow, level, and analytical or composition.Various instruments are designed to help facilitate thiscritical aspect of process work. Some of these instruments include computers, gauges, recorders,transmitters, controllers, transducers, primary elements and sensors, switches, and control valves.

Symbols and diagrams have been developed for most pieces of industrial equipment, processflows, and instrumentation. The symbols covered in this chapter include those typically used withvalves, piping, tanks, pumps, compressors, steam turbines, motors, heat exchangers, cooling tow-ers, furnaces, boilers, distillation columns, and reactors. These symbols are used in process sym-bols to describe a process unit.

Process diagrams are used to outline or explain the complex flows, equipment, instrumentation, elec-tronics, elevations, footings, and foundations that exist in and make up a process unit.These diagramscan be broken down into two major categories: process flow diagrams and piping and instrumenta-tion drawings.The PFD is typically a simplified illustration that describes the primary flow path througha unit, whereas the P&ID is a complex representation of the various units found in a plant.

An interlock is a device designed to prevent damage to equipment and personnel by stopping orpreventing the start of certain equipment functions unless a preset condition has been met. A per-missive is a special type of interlock that controls a set of conditions that must be satisfied beforea piece of equipment can be started. Permissives deal with start-up items, whereas hardwire in-terlocks deal with shutdown items. A permissive interlock will not necessarily shut down the equip-ment if one or more of its conditions are not met, but it will keep the equipment from starting up.

P-100A P-200A

P-300A P-400A

D-500

P-500A

EX-600

P-600A

20'-0"

10'-0

"

20'-0

" 18'-0" 8'-0"

20'-0

"

8'-0

"

6'-0

"

6'-0

"

20'-0"

8'-0"

16'-0"

20'-0"

TK-100 TK-200

TK-300 TK-400

C-600

TK-2

TK-3 TK-4

TK-1

Figure 7–23 Equipment Location

Chapter 7 Review Questions1. Describe a process flow diagram.

2. Describe a piping and instrumentation drawing.

3. How are instrumentation symbols shown on a P&ID?

4. Draw the symbols for a gate valve and a globe valve.

5. Draw the symbols for a centrifugal pump and a positive displacement pump.

6. Draw the symbols for a blower and a reciprocating compressor.

7. Draw the symbol for a steam turbine.

8. Draw the symbol for a heat exchanger.

9. Draw the symbol for a cooling tower.

10. Draw the symbol for a packed column.

11. Draw the symbol for a plate column.

12. Draw the symbol for a furnace.

13. Draw the symbol for a boiler.

14. Draw the symbol for a manually operated valve.

15. Draw a simple flow diagram. Include piping, pumps, two tanks, and six different valves.Provide a way to circulate and blend the material using the pumps-piping-valvesrelationship.

16. Draw a simple P&ID. Do not copy the example from the book. Be original.

17. List and describe the instruments associated with flow measurement.

18. List and describe the instruments associated with temperature measurement.

19. List and describe the instruments associated with level measurement.

20. List and describe the instruments associated with pressure measurement.

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Process InstrumentationTwoAfter studying this chapter, the student will be able to:

• Define the term control loop, and identify the five elements of a control loop.• Draw a level control loop.• Draw a pressure control loop.• Draw a flow control loop.• Draw a temperature control loop.• Discuss the function of transmitters.• Describe manual, automatic, and cascade control features.• Describe the various controller modes, rate modes, reset modes,

and proportional bands and how each complements the other.• Describe a programmable logic controller.• Describe a distributive control system.• Understand the purpose and functioning of automatic valves.

193

194

Chapter 8 ● Process Instrumentation Two

Key TermsAutomatic/manual control—term describing two modes in which controllers can be operated.During plant start-up, the controller is typically placed in the manual position. In this mode,only manual control affects the position of the control valve; it does not respond to processload changes. After the process is stable, the operator places the controller in automatic mode,which allows the controller to supervise the control loop function. At this point, the controllerwill automatically open and close the control valve to maintain the setpoint.

Cascade control—a term describing how one control loop controls or overrides the instructionsof another control loop to achieve a desired setpoint.

Control loop—a collection of instruments that work together to automatically control aprocess. A loop includes a primary element or sensor, a transmitter, a controller, a transducer,and a final control element.

Controller—device the primary purpose of which is to receive a signal from a transmitter, com-pare this signal to a setpoint, and adjust the (final control element) process to stay within therange of the setpoint. Controllers come in three basic designs: pneumatic, electronic, andelectric.

Controller modes—settings and functions that include proportional (P), proportional plus in-tegral (PI), proportional plus derivative (PD), and proportional-integral-derivative (PID). Pro-portional control is primarily used to provide gain where little or no load change typicallyoccurs in the process. Proportional plus integral is used to eliminate offset between the set-point and process variables; PI works best where large changes occur slowly. Proportional plusderivative is designed to correct fast-changing errors and avoid overshooting the setpoint; PDworks best when frequent small changes are required. Proportional-integral-derivative is ap-plied where massive, rapid load changes occur; PID reduces the amount of swing between theprocess variable and the setpoint.

Proportional band—on a controller, describes the scaling factor used to take a controller from0% to 100% output.

Range—the portion of the process controlled by the controller. For example, the temperaturerange for a controller may be limited from 80°F to 140°F.

Rate (or derivative) mode—enhances controller output by increasing the output in rela-tionship to the changing process variable. As the process variable approaches the setpoint, therate or derivative mode relaxes, providing a braking action that prevents overshooting of thesetpoint. The rate responds aggressively to rapid changes and passively to smaller changes inthe process variable.

Reset (or integral) mode—designed to reduce the difference between the setpoint andprocess variable by adjusting the controller output continuously until the offset is eliminated.The reset or integral mode responds proportionally to the size of the error, the length of timethat it lasts, and the integral gain setting.

Span—the difference between the upper and lower range limits.

8.1 Basic Elements of a Control Loop

Process technicians use instrumentation to control a variety of automated processes. The keycomponent of automatic control is the control loop, a group of instruments that work together tocontrol a process (see Figure 8–1). These instruments typically include a transmitter coupled witha sensing device or primary element, a controller, a transducer, and a control valve.

Process plants are composed of hundreds of control loops.These control loops are used to main-tain pressure, temperature, flow, level, and analytical process variables. The basic elements of acontrol loop are:

1. Measurement device—primary elements and sensors• Flow—orifice plate, flow nozzle• Level—float, displacer• Pressure—helix, spiral, bellows• Temperature—thermocouple, thermal and resistance bulb

2. Transmitter—a device designed to convert a measurement into a signal. This signal istransmitted to another instrument.• Pressure transmitter—tubing to process• Temperature transmitter—tubing to process• Flow transmitter—DP cell, high/low pressure taps• Level transmitter—hooked to float or displacer

3. Controller—a device designed to compare a signal to a setpoint and transmit a signal to afinal control element.• Recording• Indicating• Blind• Strip chart• Vertical and scale

4. Transducer—a device designed to convert an air signal to an electric signal or an electricsignal to a pneumatic signal. Sometimes referred to as an I to P or a converter.• Air signal to an electric signal• Electric signal to a pneumatic signal

5. Final control element—the part of a control loop that actually makes the change to control theprocess.• Control valve• Motor on a pump or compressor

8.1 Basic Elements of a Control Loop

195

FT

FC I/P

Pi

P&ID DWG

UNIT FEED PUMP150 GPM @ 300 PSIG

Controller

Transmitter

PrimaryElement

Transducer

Final ControlElement

Pi

Pi

Pi

Figure 8–1 Typical Control Loop

8.2 Process Variables and Control Loops

Process variables typically fall into five different groups: pressure, temperature, flow, level, and an-alytical variables. Each control loop is specifically designed to work with a selected variable.Process technicians monitor many control process variables.

Figure 8–2 shows an example of a flow control loop. Flow loops are typically designed so that ameasurement of the flow rate is taken first and then the flow is interrupted or controlled down-stream. Flow control loops start at the primary element. Flow control primary elements may includeorifice plates, venturi tubes, flow nozzles, nutating disks, oval gears, or turbine meters. The mostcommon primary element is the orifice plate, which artificially creates a high-pressure/low-pressure situation that can be measured by the transmitter. Primary elements are typically usedin conjunction with a transmitter.

Although it appears that the primary element is interrupting the flow, this is not the case. Increasedvelocity across the orifice plate compensates for the restriction. The transmitted signal is sent to acontroller that compares the incoming signal with the desired setpoint. If a change is required, thecontroller sends a signal to a final control element.

Control loop design uses the five elements of the control loop. The one area that changes consis-tently is the first: primary elements and sensors. Pressure control loops use devices to detect pres-sure changes. These primary elements are typically expansion-type devices. Primary pressureelements include bourdon, helical, spiral, bellows, pressure capsule, and diaphragm. Figure 8–3shows a pressure transmitter, controller, transducer, and control valve.

Figure 8–4 is a simple layout for a temperature control loop. In large fired furnaces, a temperaturemeasurement is taken at the furnace or from the exiting charge. The primary sensors used to de-tect temperature are thermocouples or RTDs, often called temperature elements. Like primary el-ements, temperature elements are linked to transmitters. A 4- to 20-milliamp (mA) signal is sentto a controller that compares it to a setpoint. Controllers may be located in the field near the equip-ment or in a remote location. The controller sends an electric signal to a transducer, which is typ-ically located near the valve to eliminate process lag. The transducer converts the electric signalto a pneumatic signal of 3 to 15 psi. The control valve (see Figure 8–4) opens and closes accord-ing to the signal. Temperature is controlled by reducing or increasing fuel flow to the burners.

Level control loops use floats, displacers, or differential pressure transmitters. Figure 8–5 showsa differential pressure (ΔP) cell to detect level changes. The primary element or sensor is inside

196


FT

FC I/P

Bypass LoopPrimary Element

Transmitter

Controller Transducer

Final Control Element

Flow

Figure 8–2 Flow Control Loop

8.4 Transmitters and Control Loops

197

PRESSURE

PT

PEPCV

IP

Transmitter

Sensor

Controller

Transducer


PIC

Figure 8–3 Pressure Control Loop

TT

TC

Fuel Gas

TE

I/P

Sensor

Transmitter

Controller

Transducer

Final Control Element

Figure 8–4 Temperature Control Loop

the transmitter. These two devices couple up to detect changes and send a signal to a levelcontroller. A transducer converts the signal and opens or closes the control valve.

8.3 Primary Elements and Sensors

Figure 8–6 shows the primary elements and sensors for flow, level, pressure, and temperature.


Differential pressure or ΔP cell transmitters come in two basic designs: pneumatic or electronic.Controllers are typically mounted between 400 feet (closed loop) and 1,000 feet (open loop) fromthe transmitter.The signal from an electronic transmitter is proportional to the difference in the high-and low-pressure legs. Standard output signals are 4 to 20 mA, 10 to 50 mA, and 1 to 5 volts (V).

198


LEVEL

LE LT

Controller

Transducer


LIC

IP

Figure 8–5 Level Control Loop

Primary Element Sensor

Flow Orifice plate, flow nozzle, ΔP cell(diaphragm)

ΔP cell

Level Float, displacer, ΔP cell (diaphragm) ΔP cell

Pressure Helix, spiral, bellows, bourdon tube,ΔP cell

ΔP cell

Temperature Capillary tubing, thermal & resistancebulb

Thermocouple, RTD

Figure 8–6 Primary Elements Chart

The 10–50 mA transmitter is becoming very popular because it has a higher tolerance to outsideinterference. Pneumatic transmitters require a 20-psig air supply in order to run the standard 3- to15-psig output. (See Figure 8–7.)

Differential pressure cells function by running a high- and low-pressure tap to each side of aninternal twin-diaphragm capsule. Pressure changes cause the diaphragms to move. This processincreases or decreases the signal to the controller. Figure 8–8 illustrates how a ΔP transmitteroperates.

Smart transmitters are frequently found in the chemical processing industry.This type of transmitteris very reliable and does not need constant attention. Smart transmitters have an internaldiagnostic system that warns the operator if a problem is about to occur. This type of transmittercan be used to monitor liquid or gas service, pressure, viscosity, temperature, flow, or level.Several advantageous features of the smart transmitter include speed, reliability, internaldiagnostics capability, strong digital signal, and remote calibration capabilities.


199

Air-to-Open

psi 4–20 mA Valve Position 10–50 mA 1–5 V

3 4 Closed 10 1

6 8 25% 20 2

9 12 50% 30 3

12 16 75% 40 4

15 20 100% 50 5

Figure 8–7 Pneumatic Electric Comparison Chart

HighPressure

LowPressure

Flow in

Orifice Plate

P Cell Transmitter

H L

DeltaΔ

Figure 8–8 ΔP Cell Transmitter

8.5 Controllers and Control Modes

The primary purpose of a controller (see Figure 8–9) is to receive a signal from a transmitter, com-pare this signal to a setpoint, and adjust the process (via the final control element) to stay withinthe range of the setpoint. Controllers come in three basic designs: pneumatic, electronic, and elec-tric. Electronic controllers were first introduced in the early 1960s. Before then, only pneumaticcontrollers were used. Pneumatic controllers require a clean air supply pressure of 20 psig. Sev-eral of the more attractive features of electronic controllers are the reduction of lag time in processchanges, low installation expense, and ease of installation.

As use of the personal computer (PC) became widespread, a number of applications were foundfor controller use. Distributed control systems (DCSs) began to replace the older pneumatic and

200


Figure 8–9 Controller

electronic controllers. The primary reason was the ease with which a DCS could be installed andthe relatively few wires required to do it. Most modern plants are still a combination of all threesystems—pneumatic, electronic, and electric. It is almost impossible to identify from the controlloop function what type of controller (pneumatic, electronic, or DCS) is being used.

Controllers can be operated in manual, automatic, or cascade control. During plant start-up,the controller is typically placed in the manual position and left there until the process has linedout. This process initiates a setpoint on the final control element; however, it does not utilize acontrolling function. It only opens the valve 50% or 25% and keeps it there until the technicianchanges the mode. This keeps the process from swinging up and down during start-up. Afterthe process is stable, the operator places the controller on automatic and allows it to supervisethe control loop function. At this point, the controller will open and close the control valve tomaintain the setpoint. Cascade control describes how one control loop controls or overrides theinstructions of another control loop in order to achieve a desired setpoint. In this case, a con-trol loop’s controller may use all five elements of another control loop as its final controlelement.

Proportional BandThe proportional band on a controller describes the scaling factor used to take a controller from0% to 100% output. For example, if the proportional band is set at 50% and the amount of lift thefinal control element (in this case a globe valve) has off the seat is 4 inches, the control valve willopen 2 inches. Range is the portion of the process controlled by the controller. For example, thetemperature range for a controller may be limited to 80°F to 140°F. Span is the difference (Δ)between the upper and lower range limits. This value is always recorded as a single number. Forexample, the difference between 80 and 140 is 60, so the span is 60.

Controller ModesController modes include proportional (P), proportional plus integral (PI), proportional plusderivative (PD), and proportional-integral-derivative (PID). Proportional control is primarily used toprovide gain where little or no load change typically occurs in the process. Proportional plusintegral is used to eliminate offset between the setpoint and process variables; PI works bestwhere large changes occur slowly. Proportional plus derivative is designed to correct fast-changingerrors and avoid overshooting the setpoint; PD works best when frequent small changes arerequired. Proportional-integral-derivative is applied where massive, rapid load changes occur; PIDreduces the amount of swing between the process variable and the setpoint.

Rate ModeThe rate (or derivative) mode enhances controller output by increasing the output in relationshipto the changing process variable. As the process variable approaches the setpoint, the rate orderivative mode relaxes, providing a braking action that prevents overshooting of the setpoint.Therate responds aggressively to rapid changes and passively to smaller changes in the processvariable.

Reset ModeThe reset (or integral) mode is designed to reduce the difference between the setpoint and the process variable by adjusting the controller output continuously until the offset is elim-inated. The reset mode responds proportionally to the size of the error, the length of time thatit lasts, and the integral gain setting.

8.5 Controllers and Control Modes

201

Tuning ControllersTuning controllers:

• Turn rate action off• Set integral (reset) action to minimum• Establish arbitrary gain• Set controller to AUTO mode

– reduce gain if process swings– increase gain if process response is too slow

A graph of the process should be a straight line when the process is in control.

Programmable Logic ControllersA programmable logic controller is a modern control system that combines microprocessor fea-tures with software-configurable controllers.The basic components of this system include proces-sor CPU (central processing unit) module; mounting rack; power supply; user-defined, plug-ininput/output modules; and communication interface module. This type of system requires minimalspace, is extremely reliable, is reprogrammable, and has high computational ability. Anotherattractive feature is that laptop computers can interface with and program the system.

Distributive Control SystemsDistributive control systems combine some of the most innovative technologies into an interactivenetwork of intelligent microprocessors, application software, and communication networks. Thehardware for a DCS includes a host CPU or programmable logic controller (PLC), intelligent fielddevices (transmitters, controllers, and control valves), remote CPU, and keyboard. This type ofsystem offers the highest level of operator interaction.

8.6 Final Control Elements and Control Loops

Automatic ValvesFinal control elements are typically automated valves; however, motors or other electrical devicescan be used. The final control element is the last link in the modern control loop and is the devicethat actually makes the change in the process. Automatic valves open or close to regulate theprocess. Control loops usually have (1) a sensing device, (2) a transmitter, (3) a controller, (4) atransducer, and (5) an automatic valve. Automatic valves can be controlled from remote locations,making them invaluable in modern processing.

To automate a valve, a device known as an actuator is installed.The actuator controls the positionof the flow control element by moving and controlling the position of the valve stem.

Actuators come in three basic designs:1. Pneumatically (air) operated—This is the most common type of actuator. Pneumatic

actuators convert air pressure to mechanical energy and can be found in three designs:(1) diaphragm, (2) piston, and (3) vane.1. Diaphragm—The diaphragm actuator is a dome-shaped device that has a flexible di-

aphragm running through the center. It is typically mounted on the top of the valve. Thecenter of the diaphragm in the dome is attached to the stem.The valve position (on or off)

202


is held in place by a powerful spring. When air enters the dome on one side of the flexi-ble diaphragm, it opens, closes, or throttles the valve, depending on the valve design.

2. Piston—The piston actuator, which uses an airtight cylinder and piston to move or posi-tion the stem, is commonly used in combination with automated gate valves or slidevalves. It is also used where a lot of stem travel is needed.

3. Vane—Vane actuators direct air against paddles or vanes.2. Electrically operated—This actuator converts electricity to mechanical energy. Examples are

the solenoid valve and the motor-driven actuator.• Solenoid valves are designed for on-off service. The internal structure of a solenoid resem-

bles a globe valve. The disc rests in the seat, stopping flow. The stem is attached to a metalcore or armature that is held in place by a spring. A wire coil surrounds the upper spring andstem. When the wire coil is energized, a magnetic field is created, causing the armature tolift and compressing the spring. The armature is held in place until the current stops.

• A motor-driven actuator is attached to the stem of a valve by a set of gears. Gear movementcontrols the position of the stem.

3. Hydraulically operated—This type of actuator converts liquid pressure to mechanical energy.The hydraulic actuator uses a liquid-tight cylinder and piston to move or position the stem.These are commonly used in combination with automated gate valves or slide valves, andare also used where a lot of stem travel is needed.

Common terminology for actuators includes:• Air to open, spring to close—fails in the closed position if air system goes down.

Air line is typically located on the bottom of the dome.• Air to close, spring to open—fails in the open position if air system goes down.

Air line is typically located on the top of the dome.• Double-acting, no spring—air lines located on both sides of the dome.

The most common type of automated valve is a globe valve, because of its versatile, on-off or throt-tling feature. Control loops use on-off or throttling-type valves to regulate the flow of fluid in andout of a system. Automatic valves can be used to control pressure, temperature, flow, or level.

Automatic valves fall into the following categories:1. Control valve—air-operated, electrically operated, hydraulically operated.2. Spring- or weight-operated—hold the flow control element in place until pressure from

under the disk grows strong enough to lift the element from the seat (e.g., check valve).

Summary

A control loop is a group of instruments that work together to control a process.These instrumentstypically include a transmitter coupled with a sensing device or primary element, a controller, atransducer, and a control valve. There are five typical process variables: pressure, temperature,flow, level, and analytical. Control loops are specifically designed to work with a selected variable.

The primary purpose of a controller is to receive a signal from a transmitter, compare this signalto a setpoint, and adjust the process (using a final control element) to stay within the range of thesetpoint. Controllers come in three basic designs: pneumatic, electronic, and electric.

Summary

203

A programmable logic controller is a modern control system that combines microprocessor fea-tures with software-configurable controllers.The basic components of this system include proces-sor CPU module, mounting rack, power supply, user-defined plug-in input/output modules, andcommunication interface module.

Distributive control systems combine some of the most innovative technologies into an interactivenetwork of intelligent microprocessors, application software, and communication networks. Thehardware for a DCS includes a host CPU or PLC, intelligent field devices (transmitters, controllers,and control valves), remote CPU, and keyboard.

Final control elements are typically automated valves; however, motors or other electrical devicescan be used. The final control element is the last link in the modern control loop and is the devicethat actually makes the change in the process.

Actuators for control valves come in three basic designs: pneumatic, electric, and hydraulic. Pneu-matic actuators, which convert air pressure to mechanical energy, use three designs: diaphragm,piston, and vane. Electrically operated actuators convert electricity to mechanical energy. Com-mon examples include solenoid valves and motor-driven actuators. Hydraulically operated actua-tors convert liquid pressure to mechanical energy. The hydraulic actuator uses a liquid-tightcylinder and piston to move or position the valve stem.

204



205

Chapter 8 Review Questions1. List the three basic designs for valve actuators.

2. Describe the system designated by the terms “air to open” and “air to close.”

3. Define proportional control.

4. Describe rate and reset.

5. List the primary elements and sensors associated with flow.

6. List the primary elements and sensors associated with level.

7. List the primary elements and sensors associated with pressure.

8. List the primary elements and sensors associated with temperature.

9. List the five elements of a control loop.

10. Draw a pressure control loop and label its parts.

11. Draw a flow control loop and label its parts.

12. Draw a level control loop and label its parts.

13. Draw a temperature control loop and label its parts.

14. Describe how proportional control works with reset.

15. Describe how proportional control works with rate.

16. Describe a programmable logic controller.

17. Describe a distributive control system.

18. Describe how a 3–15 psi pneumatic signal relates to a 4–20 mA electric signal.

19. What is a smart transmitter, and what are some of its advantages?

Process Technology—Systems OneAfter studying this chapter, the student will be able to:

• Describe a simple pump-around system.• Identify the key components of a compressor system.• Describe common turbines and a gas turbine system.• Identify the key components of an electrical system.• Describe a simple lubrication system.• Identify the key components of a hydraulic system.• Identify the basic components of a heat exchanger system.• Identify the primary components of a cooling-tower system.• Describe the basic components of a steam-generation system.• Describe the important aspects of a fired heater or furnace system.• Explain the relationship between cooling towers and heat exchangers.

207

208

Chapter 9 ● Process Technology—Systems One

Key TermsCompressor system—key elements of this system include piping, valves, a compressor, areceiver, heat exchangers, dryers, back pressure regulators, gauges, and moisture removalequipment.

Cooling-tower system—includes a cooling-tower and pipe system to transfer cooled water tothe unit and back to the cooling-tower water-distribution system. The cooling tower has aseries of complex instrument systems to control ppm, pH, level, temperature, fan speed, andflow rate.

Electrical system—system composed of a boiler, a steam turbine, a main substation withtransformers, a motor control center, and electrically powered equipment.

Furnace system—typically used to heat up large quantities of hydrocarbons or chemicals. Thebasic equipment in a furnace system includes a furnace, advanced process control systems andinstruments, pump systems, compressor systems, and fuel systems.

Heat exchanger system—consists of shell in/out piping; tube in/out piping; valves; instru-ments; flow, temperature, analytical, and pressure control loops; and two separate pump systems.

Pump-around system—consists of a series of piping, storage tank(s), valves, gauges, anda pump.

Steam-generation system—a complex arrangement of boiler systems designed to convertwater to steam. These include pump-around systems, advanced process control systems andinstruments, fuel systems, and compressor systems.

9.1 Pump System

New technicians have difficulty determining which pieces of industrial equipment go together whenasked to develop a simple flow diagram. Figure 9–1 illustrates the basic equipment found in a typi-cal pump-around system. Using a simple pump-around system, technicians can learn how to per-form equipment line-ups, start-ups, operational checks, and shutdowns. A key question thatapprentice technicians need to answer is how to redirect flow from an operating pump, whetherdynamic or positive displacement.The key elements of a pump-around system include process pip-ing, storage tank(s), valves, gauges, and a pump.Scientific principles associated with pumps includefluid flow characteristics, pressure, temperature, heat transfer, electricity, rotation, and kinetic energy.

9.2 Compressor System

A compressor system is a simple arrangement of equipment designed to produce clean, dry,compressed air or gas for industrial applications. Compressors are also used to transfer or com-press light hydrocarbon gases, nitrogen, hydrogen, carbon dioxide, chlorine, and a large variety ofspecialty gases. Compressors are used at pipe-line lift stations to add energy to compressed feed-stocks. Compressor systems are also used to transfer granular and flake polymer and additives

and small plastic pellets from one place to another. In natural gas plants, compressors are usedto establish feed-gas process pressures.

A compressor system typically includes process piping, valves, a compressor, a receiver, heatexchangers, dryers, back pressure regulators, gauges, and moisture removal equipment. Thesequence and equipment arrangement is illustrated in Figure 9–2. Additional information aboutcompressor systems can be found in Chapter 5. Scientific principles associated with compressorsinclude fluid flow characteristics, pressure, temperature, heat transfer, electricity, rotation, andkinetic energy.

Typical Compressor SystemIn a refinery or chemical plant, compressors are used to compress gases like nitrogen, hydrogen,carbon dioxide, and chlorine. These gases are sent to headers from which they are distributed toa variety of applications. Compressors also provide clean, dry air for instruments and control


209

FT

I P

Pi

FR

FIC

Centrifugal Pump B

Centrifugal Pump A

202

LA

Ti

Pi

Pi

FT

I P

FIC

LE LT

(Feed Tank)

LIC

NPSH

NPDH

To Flare

Pi

Hi

Lo

85%

65%

Pressure Relief

Figure 9–1 Pump-Around System

devices.When compressors are used in a process system, a wide assortment of supporting equip-ment is required. A small sample of this list could include the compressor, receiver, safety valves,heat exchangers, motor, lubrication systems, control instruments, valves, dryers, demister, regu-lators, and pipe header.

Typical Turbine SystemsTurbines are classified according to their principle of operation and the type of fluid that turns them.All turbines respond to impulse or reaction movement. The four main types of turbines are steamturbines, gas turbines, wind turbines, and water turbines. The primary function of a turbine is toconvert steam, gas, wind, or water energy into mechanical energy that can be used to driverotating equipment.

Gas Turbine System (Industrial Driver)A gas turbine is a device that uses high-pressure combustion gases to turn a series of turbinewheels to provide rotational energy to a driven device. Gas turbines are used to operate electricgenerators, ships, and racing cars, and as a primary component of jet aircraft engines. The gasturbine does this by providing the rotational energy needed to turn an axle or shaft.There are threeprimary parts of a gas turbine system: an axial compressor, a combustion chamber, and a gas

210


Centrifugal Compressor(Multi-Stage)

Instrument Air Header

IP

PE

PTPIC Pi

PiPi

Pi

Airinlet

ON

OFF

Dryers

Receiver

Steam

M

Figure 9–2 Compressor System

turbine.The gas turbine system mixes compressed air with fuel in a combustion chamber. A sparkplug ignites the mixture, which is directed into the suction side of the gas turbine. The hot com-bustion gases rush into the gas turbine, causing the turbine wheels to turn. Hot exhaust gases aredischarged from the body of the gas turbine.The air compressor and the gas turbine are mountedto the same axle, which is connected to the workload (Figure 9–3).

When an air compressor and a combustion chamber are used in combination with each other, itis frequently referred to as a gas generator. During operation, a fraction of the power generatedby the turbine is used to run the compressor. When the air compressor pulls air into the system, itincreases the pressure. When the compressed air mixes with the fuel and is ignited, the higherpressure allows the mixture to burn better. The fuel used to operate a gas turbine is natural gas oroil. The hot combustion gases produced by the gas or oil is used in the same way a steam turbine


211

L

L

L

L

Air In

Jet Engine

Exhaust Gases

Nozzle

Tailpipe

TurbineCompressor

Spark Plug

Combustor Assembly

FuelInjector

Axle

Fire Water Pump

Pi

Pi

Air inlet

Figure 9–3 Gas Turbine System

uses steam to turn the rotor. The air for combustion is generally filtered through a bag-housearrangement to remove airborne contaminants, which would settle on turbine components.

9.3 Electrical System

An electrical system is designed to provide electricity to operate motors, lights, electric plugs, fans,computer equipment, control instrumentation, cameras, motor control centers, and many other in-struments and areas. Electricity is generated by an electric generator. Typically, boilers providesteam that turns a steam turbine, which in turn rotates the electric generator, producing electric-ity. Electrical systems (see Figure 9–4) are a collection of complex processes that include a boilerto generate steam, a steam turbine, an electric generator to produce electricity and create the loadfor commercial distribution, insulated wiring, a main substation with transformers to reduce theelectrical output, a motor control center (MCC) to centralize local power distribution, and electri-cally powered equipment that is run by the electrical system.

Process technicians are not trained as electrical technicians; however, safely operating a systemthat uses electricity requires a comprehensive education. Only qualified electricians work onindustrial electrical systems that can have very high voltages. Typically, two electricians work on

212


BoilerSteamTurbine

GeneratorMain

Substation

69,000 Volts

69 kV

MCC

13,200 V13, 800 V2,300 V

13.2 kV13.8 kV2.3 kV

OnOff

Motor2.3 kV or480 Volts

Transformer

Voltmeter

MCC

SSSSSSSS

SSSSSSSSSSS

SSSSSSSSS

SSSS

Iron CoreRotor

Stator Windings

Stator Core

Bearings

Rotating Magnetic + -(Cause Rotation)

Figure 9–4 Electrical System

9.5 Hydraulic System

213

FluidReservoir

CompressorBearings

Gearbox

PumpBearings

PIC

TIC

PT

PE

TT

TE

IP

IP

Figure 9–5 Lubrication System

projects together to ensure personal safety.Process technicians closely monitor substation variablesand electrical equipment operations.Worn belts on motor systems, exposed wiring, smoking motors,fires, arcing, or strange electrical smells are reported immediately.

9.4 Lubrication System

Lubrication systems provide a constant source of clean oil to pump and compressor bearings,gearboxes, steam turbines, and rotating or moving equipment. A typical lubrication system includesa lubricant reservoir, pump, valves, heat exchanger, and piping. Figure 9–5 illustrates how anindustrial lubrication system operates.

9.5 Hydraulic System

Process technicians use hydraulic systems (see Figure 9–6) to open or close valves, lift heavyobjects, run hydraulic motors, and stop the rotation of a rotary or reciprocating device. A hydraulicsystem is a collection of equipment designed to apply pressure on a confined liquid in order toperform work. A similar process is used in the brake systems of most cars and trucks. A hydraulicsystem is composed of a fluid reservoir, strainer, pump, piping, flow control valve, pressure con-trol valve, four-way directional control valve, and actuator (cylinder, piston).

9.6 Heat Exchanger System

Heat transfer is an important process in the chemical processing industry. A heat exchanger is adevice used to transfer heat energy from a hotter fluid to a cooler fluid. Heat exchangers come ina variety of designs, including shell-and-tube, air-cooled, spiral, and plate. Heat exchangers usethe principles of conductive and convective heat transfer. A heat exchanger system consists ofshell in/out piping; tube in/out piping; valves; flow, temperature, analytical, and pressure controlloops and instruments; and two separate pump systems.

A heat exchanger system typically includes two, three, four, or more heat exchangers working to-gether in series or parallel operation.These systems can appear very complicated for a new tech-nician, because each exchanger has a separate tube inlet and outlet system and shell inlet andoutlet system. Steam, hot oil, or a previously heated process stream can be used as the heatingmedium. As heat energy is transferred between process flows, process variables are closelyobserved. Figure 9–7 shows what a typical heat exchanger system looks like.

9.7 Cooling-Tower System

A cooling-tower system includes a cooling tower and pipe system to transfer cooled water to theunit and back to the cooling-tower water-distribution system. The cooling tower uses a series ofcomplex instrument systems to control ppm, pH, level, temperature, fan speed, and flow rate.Cooling-tower systems are very complex and can be challenging for new technicians to master.As the water flows from the cooling tower to the operational processes, it picks up heat andsuspended solids. As this heated water is returned to the cooling tower, these suspended solidsbegin to accumulate in the basin and on the internal components of the tower. These suspendedand dissolved solids can change the pH and conductivity of the water system.

214


XXX

Directional Control Valve

Pressure Control Valve

Flow Control Valve

Actuator Strainer

Fluid Reservoir

Pump

Figure 9–6 Hydraulic System

9.7 Cooling-Tower System

215

FT

IP

Ti

Pi

FR

FIC

AT

TR


180ºF FO

180.5 ºF

Ti

Ti

225 ºF

200 ºF

Pump

TAH

Ti115ºF

Ti

Fi

Ti80ºF

80ºF Liquid

222ºF Liquid

Tube Inlet

Bypass

Bypass

Shell Inlet

Pi

Pi

225 GPM

Heat Exchanger

Heat Exchanger

IP

TIC TETT

Pi

Pi35 psig

195ºF

173ºF

130psig

135psig

135 psig

Pump

625 GPM

40 psig

Figure 9–7 Heat Exchanger System

216

Figure 9–8 illustrates what a cooling-tower system looks like. A cooling-tower system also includesthe following control features: basin level control, basin pH control, chemical additive control, partsper million (ppm) control, temperature control, flow control, and fan speed control.

Heat Exchangers and Cooling TowersHeat exchangers and cooling towers are often paired in industrial cooling systems. The systemconsists of a cooling tower, heat exchanger, and pump. During operation, cooling water is pumpedinto the shell side of a heat exchanger and returned (much hotter) to the top of the cooling tower.As the hot water goes into the top of the cooling tower, it enters a water-distribution header whereit is sprayed over the internal components (fill ) of the tower (Figure 9–9). As the water falls on thesplash bars, contact occurs between cooler air and the water. Ten to 20% of the sensible heat isremoved by this process. Another 80% to 90% of the heat energy is removed through evaporation.The cooled water collects in a basin at the foot of the cooling tower, where a recirculation pumpsends it back to the heat exchanger.

9.8 Steam-Generation System (Boilers)

The production of steam is very important to the operation of an industrial facility. Steam is usedin a variety of operations, including heating and temperature control, steam turbines, steamtracing, heat exchangers, reboilers, stripping, and distillation. The energy in steam can easily be


TR

IP

IP

AIC AICBlowdown

LIC

30 PPM4.5

7.8 pH

75%

125ºF

125ºF

60ºF

160ºF

130ºF

525gpm

515gpm

On

Off

TE

Ti

TT

FE

FT

TIC

Ti

TiPi

Pi

Fi

AEAE

TT

LT

AT AT

AE

AT

TE

IP

IP

TIC

FIC

SIC

IP

IP

AIC

IP

1250RPM

COOLING TOWER

Ti

LAPump

Low PressureSteam

Heat Exchanger“Condenser”

Hi

Low

AAHi

Low

75ºF

50 psig

45 psig

85ºF

SEST

Figure 9–8 Cooling-Tower System

transformed into mechanical or heat energy upon condensation. A typical steam-generationsystem includes super-high-pressure (SHP) steam generation and distribution, high-pressure(HP) steam (400–800 psig), medium-pressure (MP) steam (200 psig), and low-pressure (LP)steam (50 psig). SHP steam can be as high as 1,200 psig. The heat value for steam is easily cal-culated, because it generally corresponds to the pressure. The following are some typical steamtemperature and pressure relationships:

274°F @ 30 psig298°F @ 50 psig338°F @ 100 psig388°F @ 200 psig421°F @ 300 psig448°F @ 400 psig470°F @ 500 psig489°F @ 600 psig

A steam-generation system is designed to safely return cooled condensate to the boiler. A devicecalled a steam trap is used to collect and transfer this material. Low points in the steam systemare used to capture cooled condensate before it can damage the piping or equipment. Water canexpand to many times its original volume when vaporized, so the condensate return header is a

9.8 Steam-Generation System (Boilers)

217

TR

IP

IP

AIC AICBlowdown

LIC

30 PPM4.5

7.8 pH

75%

125ºF

125ºF

60ºF

160ºF

130ºF

525gpm

515gpm

On

Off

TE

Ti

TT

FE

FT

TIC

Ti

145ºF

Ti

Ti

Pi

Pi

Fi

AEAE

TT

LT

AT AT

AE

AT

TE

IP

IP

TIC

FIC

SIC

IP

IP

AIC

IP

1250RPM

COOLING TOWER

Ti

LAPump

ParallelFlow

Low PressureSteam

Heat Exchanger“Series Flow”

Hi

Low

AAHi

Low

75ºF

50 psig

45 psig

85ºF

SE

Ex

ST

Figure 9–9 Cooling Tower and Heat Exchanger System

218


T To Units

T T T

LOW

To Units

T T T

To Units

T T T

HIGH

MEDIUM

Condensate Return

Deaerator

Boiler

FlashTank

FeedTank

BFWPump

CondensateTank

Low Pressure Condensate

To CondensateTank

ToCondensate

TankWater

Make-Up Vent

400–800 psig

180–200 psig

50 psig

Figure 9–10 Steam-Generation System

critical part of the system. Water is also basically noncompressible, and at high velocities canseriously damage equipment. Figure 9–10 shows the many applications in which steam is used.

The heart of a steam-generation system is the boiler that produces steam for the high, medium,and low steam systems. A condensate return system captures and returns condensate to theboiler. Figure 9–11 shows how each part in the steam generation system works.

9.9 Furnace System

The chemical processing industry uses fired heaters to heat large quantities of crude oil and otherhydrocarbon feedstocks up to operating temperatures for processing. For this reason, the furnace

system supports a number of other major processes, including raw material transportation andstorage, utilities, distillation, and reaction systems.The furnace system itself is a collection of othersystems linked together to produce a specific result. The furnace is composed of a firebox, outershell, lower radiant section, upper convection section, insulation, refractory material, convectiontubes, radiant tubes, stack, damper, and burners.

A typical furnace system (see Figure 9–12) includes an established raw-material storage system.This system includes storage tanks, pumps, pipes, and valves that work together in a complex net-work. Raw materials are brought in by pipeline, ship, barges, and trucks. Raw materials are typi-cally prepared for introduction into the furnace through processes such as desalting, heating,blending, or the addition of special chemicals or additives. As the heated feed leaves the furnace,it is transported to a wide assortment of chemical processes.

Furnace systems play a vital role in modern manufacturing. Typical systems supported by afurnace system include:

• Steam generation• Utilities and steam production• Distillation and mixture separations• Reactors and chemical reactions• Electric power generation

9.9 Furnace System

219

FICFIC

LIC

Ti

Pi

PR

o

PIC

Burner(s)

o

PIC

FIC

TR

Fan

Fan

To Header

Natural Gas Tank

Deaerator

Pump

Treatedwater

LPSteam

FT

FE

PT

PT

PE

PE

50%

50%

50%

-.05

-.02

-.02120 psig

50%150 GPM

Boiler System

PiTE

TE

TE

TE

450ºF

305ºF 350ºF

600ºF

500ºF

IP

350ºF

FT

LT LE

FEFTFE

IP

IP

BA

Pi

Pi

60 psig

Pi

155 psig

PA

LR

LAL

IP

Hi

LowPA Hi

Low

LR

LAL

35%

35%

Ai

AA Hi

Low0-10% Oxygen

IP

DesuperheatedSteam

Superheated

º

# per hour of steamrequired at full load.

50 psig

150 psig 100 psig

75 psig

60 psig

on/off

Stack

LIC

LT LE

IP

Vent

Figure 9–11 Steam-Generation System: How Each Part Works

220


Furnace OperationDuring operation, a furnace technician carefully observes and reacts to the amount of oxygen inthe system. Draft gauges and O2 analyzers are used to determine the correct oxygen percentagesfor optimal operation. Snuffing or purging steam or nitrogen is used to purge oxygen and fuel outof the system in the event of a flameout or equipment failure. Purging steam is also used to preheatthe furnace, remove coke from lines, and protect the furnace during various emergency situations.

A recent study indicated that the majority of plants are spending more money on the refurbishmentof existing furnace systems than on the purchase of new fired heaters. It is a common practice toadd air preheaters and modern instrumentation to improve operation.

Furnace ClassificationsA furnace can be classified as natural, induced, forced, or balanced draft. The pressure inside awarm furnace is typically lower because of buoyancy differences between air inside the furnaceand the cooler outside air. A natural-draft furnace can operate using this approach; however, whenfans are used to push or pull air through the furnace, greater heat transfer rates can be achieved.A natural-draft fired heater is severely limited in contrast to these systems. Figure 9–13 shows thefour different systems used to control airflow.

Burners and Fuel Heat ValuesThe fuel typically used in modern fired heater design is natural gas. Fuel heat values are importantvariables in economic operation of a furnace system. Heat value refers to the known differencesin the heat energy released when different fuels burn. Natural gas has a heat value of 909 Btu/ft3.

Furnace

Steam

1 2 3 4

FuelOil

Tank

Pump

Pump

Charge In

HeatExchanger

HeatExchanger

PilotFuel

ChargeOut

Figure 9–12 Furnace (Fired Heater) System

221

A number of older fired heaters burn oil and require a number of auxiliary systems to operate.The types of burners used in fired heaters include premix, combination, raw gas, and gas or oil.

Many systems use steam to help atomize the heated fuel at the point of ignition. Primary air pro-vides oxygen to the fuel mixture. Primary air is located at the point on the burner where air andfuel mix, whereas secondary air registers are located on the bottom and sides of the burner.Flame patterns are important to an experienced technician and can provide an indication of howthe system is working. Visual checks are possible at different points on the fired heater.

Furnace ProblemsDuring normal operations, checklists and samples are collected as advanced instrumentationmonitors the process. The types of problems a fired heater or furnace system typically encounterinclude: flame impingement on tubes, coke buildup inside the tubes, hot spots inside the furnace,fuel composition changes, burner flameout, control valve failure, and feed-pump failure. Otherproblems may include incorrect temperature indicator readings, failure of oxygen analyzers, oxy-gen leaks on the furnace, and the unexpected shutdown of downstream equipment. A fired heatersystem is designed to run almost continuously, 24 hours a day, 7 days a week. The operationalteam is in place to ensure that the equipment and systems operate safely, effectively, and producea quality product that meets or exceeds customer expectations.

Summary

New technicians often have difficulty determining which pieces of industrial equipment go togetherwhen asked to develop a simple flow diagram. Using a simple pump-around system, technicianscan learn how to perform equipment line-ups, start-ups, operational checks, and shutdowns. The

Summary

PreheatedAir

PreheatedAirInduced Draft Natural Draft

Forced Draft Balanced Draft

Air Air

Fan

Fan Fan

Fan

Figure 9–13 Fired Heater Draft Designs

key elements of a pump-around system include process piping, storage tank(s), valves, gauges,and a pump.

A compressor system, which is a simple arrangement of equipment designed to produce clean,dry, compressed air or gas for industrial applications, typically includes process piping, valves, acompressor, a receiver, heat exchangers, dryers, back pressure regulators, gauges, and moistureremoval equipment.

Electrical systems are a collection of complex processes that generate steam, produce electricity,reduce electrical output, centralize local power distribution, and run electrically powered equip-ment. Lubrication systems provide a constant source of clean oil to pump and compressor bear-ings, gearboxes, steam turbines, and rotating or moving equipment. Hydraulic systems, which aredesigned to apply pressure on a confined liquid in order to perform work, are used to open andclose valves, lift heavy objects, run hydraulic motors, and stop the rotation of a rotary or reciprocatingdevice.

A typical steam-generation system includes generation and distribution of super-high-pressuresteam (up to 1,200 psig), high-pressure steam (400–800 psig), medium-pressure steam (200 psig),and low-pressure steam (50 psig).The heat value for steam generally corresponds to the pressure.

222


223


Chapter 9 Review Questions1. Identify the equipment used in a pump-around system.

2. Identify the equipment used in a compressor system.

3. Identify the equipment used in a lubrication system.

4. Identify the equipment used in an electrical system.

5. Identify the equipment used in a hydraulic system.

6. Describe the primary equipment and components found in a steam-generation system.

7. Describe the primary equipment and components found in a furnace system.

8. Draw a simple pump-around system.

9. Explain how a heat exchanger system operates.

10. List the basic components of a gas turbine system.

Process Technology—Systems TwoAfter studying this chapter, the student will be able to:

• Describe the different type of reactors used in the chemical processing industry.• List the unique characteristics of a reactor system and explain how it is

different from other industrial processes.• List the critical process variables associated with reactor operation.• List the primary components of a distillation system.• Compare and contrast absorber columns and adsorption columns.• Describe how a scrubber operates.• Compare and contrast separation and distillation systems.• Describe the basic equipment used in pressure relief systems.• Describe the various equipment pieces found in a flare system

and how it operates.• Describe typical plastics plant equipment.• Explain how an extruder operates.• Explain how a refrigeration system works.• Identify the basic equipment used in a refrigeration system.• Describe how a water treatment system works.• Identify the basic equipment used in a water treatment system.• Describe the various systems found in utility sections of process plants.• Explain the functions and typical components of a utility system in a refinery

or chemical plant.

225

226

Chapter 10 ● Process Technology—Systems Two

Key TermsAbsorber—device used to remove selected components from a gas stream by contacting thestream with a gas or liquid.

Adsorber—device (such as a reactor or a dryer) filled with porous solid designed to removegases and liquids from a mixture.

Demineralizer—a filtering-type device that removes dissolved substances from a fluid.

Extract—composed of the solute and the heavier solvent; will layer out or naturally separatefrom the lighter raffinate. The heavier extract does not flow over the weir; rather, it goes outthe extract discharge port.

Extruder—a complex piece of equipment composed of a heated jacket, a set of screws or ascrew, a heated die, a large motor, a gearbox, and a pelletizer. An extruder converts raw plas-tic material into pelletized plastics ready for further processing into finished products. Mostextruders use a single- or twin-screw design surrounded by a heated barrel. The molten poly-mer is forced or pumped through a die.

Flare system—safely burns excess hydrocarbons. A flare system is composed of a flare, knock-out drum, flare header, fan optional, steam line and steam ring, fuel line, and burner.

Layer out—a process in which two liquids that are not soluble separate naturally from eachother (example: oil and water).

Packed distillation column—system filled with packing to enhance vapor-liquid contact toseparate the components in a mixture by boiling point. The most common types of packinginclude sulzer, rasching ring, flexiring, pall ring, intalox saddle, berl saddle, metal intalox,teller rosette, and mini-ring packing. The basic components of a packed column include a feedline, feed distributors, a shell, hold-down grids, random or structured packing, packing sup-port grids, bed limiters, a bottom outlet, a top vapor outlet, instrumentation, and an energybalance system. Packed columns are designed for pressure drops between 0.20 and 0.60 inchesof water per foot of packing material.

Plate distillation column system—has trays that are designed to enhance vapor-liquidcontact in the distillation process. Plate columns may be bubble-cap, valve tray, or sieve tray.The basic components of a plate distillation column include a feed line, feed tray, rectifying orenriching section, stripping section, downcomer, shell, reflux line, energy balance system,overhead cooling system, condenser, preheater, reboiler, accumulator, feed tank, product tanks,bottom line, top line, side stream, and advanced instrument control system.

Pressure relief system—safety system that includes relief valves, safety valves, rupture discs,piping, drums, vent stacks, pressure indicators, pressure alarms, pressure control loops, andflare systems.

Raffinate—the lighter material in the feedstock that is free of the solute or material beingdissolved; flows over the weir in the separator.

Refrigeration system—used to provide cooling (e.g., air conditioning) to industrial applica-tions. Refrigeration units are composed of a compressor (high-pressure refrigeration gas), heatexchanger–cooling tower combination, receiver, expansion valve (low-pressure refrigerationliquid), and heat exchanger (evaporator)–low-pressure refrigerant gas unit.

227

Figure 10–1 Reactor Designs

FIC

FIC

FIC

FIC

Feed to RX

Feed to RX

Feed to RX Feed to RXFeed to RXFIC

FIC

Fixed Bed(Converter)

Reactor

Fixed BedCatalyst

Heat In HeatIn

HeatOut

Jacketed RX

RecycleRX

Burner

Flue Gas

Direct FiredRX

EX

Pump

11

2

FIC2

10.1 Reactor System

Scrubber—device used to remove chemicals and solids from process gases.

Solute—material that is dissolved in liquid–liquid extraction.

Solvent—chemical that will dissolve another chemical.

Separation system—designed to separate two liquids from each other by density differences;typically, a solvent is introduced that will dissolve one of the components in the mixture,enhancing the separation process. A separator has a shell, weir, vapor cavity, feed inlet, extractport and pump, and raffinate port and pump.

Stirred reactor—typically includes a vessel, a mixer, valves, piping, two or more inlet ports,and a single outlet port. Reactors are complex analytical devices that have control features fora wide array of process variables and come in a variety of shapes and designs.

10.1 Reactor System

Reactor SystemHeated or cooled chemicals can be sent to reactors that are designed to combine chemicals andform new products. Reactors come in a variety of shapes and designs, such as stirred, fluidized,fixed-bed, and tubular (Figure 10–1). Reaction technology can be described as batch, semi-batch,or continuous operation. Reactors are vessels designed to allow a reaction to occur as two or more

Figure 10–2 Typical Reactor System

flows are exposed to each other under a variety of conditions; variables include heat, cold, pres-sure, concentration, time, or presence of a catalyst. A typical stirred reactor is composed of avessel, a mixer, valves, piping, two or more inlet ports, and a single outlet port.

Figure 10–2 shows a reactor system with a distillation column being used to separate the variouscomponents in the mixture. The central feature of this process is a stirred reactor that has a con-trolled flow rate of reactant B and a controlled catalyst flow rate of C. Reaction time is enhancedby the agitation of the stirred reactor. Reactant B and catalyst C combine to form product A. Thereaction does not convert 100% of reactant B and catalyst C; however, a significant amount ofproduct A exits from the reactor. The distillation column is designed to separate components A, B,and C from the mixture by their unique boiling points. The distillation column does not change themolecular structure of the feed. The scientific principle underlying this process rests firmly on thereactor system and the chemical reaction between reactant B and catalyst C.

10.2 Distillation System

A distillation process uses a complex arrangement of systems that includes a cooling-tower sys-tem, pump-and-feed system, preheat system, product storage system, compressed-air system,steam-generation system, and complex instrument control system. (See Figure 10–3.) Each ofthese stand-alone systems is designed to support a specific part of the distillation process. Each

228


A

B

C

B

C

StirredReactor

BB

B

B

B

C

C

C

C

Catalyst

Flare

Feed

Feed

Pump

HotOil

A

AA

DistillationColumn

PIC

TIC

TIC

LIC

TIC

FIC

LIC

LIC

LIC

FICFIC

ABC

Figure 10–3 Distillation System

chemical substance has a unique boiling point. The distillation process was developed to take ad-vantage of this principle, in that it separates the various components in a mixture by the differencesin their volatilities. In this type of system, a distillation column is the central piece of equipment.Distillation columns use either a plate or a packed design.

Distillation systems are used in a wide variety of applications, including:• Separating salt water from sea water to create distilled water• Separating crude oil into various fractions, such as gasoline, jet fuel, diesel,

lubricants, etc.• Separating air into oxygen, nitrogen, and argon• Separating and concentrating higher alcohol concentration in fermented solutions

Products made by distillation include natural gas, propane, butane, gasoline, kerosene, jet fuel,light oil, and heavy oil. These products can be used to make plastic, synthetic rubber, medicine,chemicals, and many other useful compounds and components.


229

Flow Diagram Process Unit

T

Furnace

Feed Tank

Bottom Tank

To BoilerCompressor

(Turbine Driven)

DryersBoiler


Cooling Tower

Reactors

ProductTank

2

ProductTank

1

Vacuum Pump

Column

Drum

Chemical engineering emerged as a discipline in the 1890s, as a science that employed empiri-cal methods. However, the “new” discipline had a long history. The first distillation system (appa-ratus) was used by Babylonian alchemists in Iraq (Mesopotamia) in 2000 BCE. Large-scale(spirits) distillation was practiced by Greek alchemists in 100 AD. Detailed instructions for a distil-lation process were written by an Alexandrian named Zosimos in the fourth century CE. Other sig-nificant contributions included those of:

• Jabir ibn Hayyan (Geber), a Persian, 800 AD, who was the first to use alembics andretorts or multiple chemical apparatus. An alembic (feed flask) and retort (accumulator)are glassware vessels; the apparatus has a long tapering neck that slopes downward.The distance between the alembic and the retort acts as a type of air-cooled condenser.

• al-Razi (Rhazes), a Persian, 900 AD, who was the first to distill petroleum for thepurpose of separating kerosene.

• Avicenna, 1100 AD, who invented steam distillation.• Hieronymus Braunschweig, a German, 1500 AD, who published The Book of the Art

of Distillation.• John French, 1651, who published The Art of Distillation. This book, which included

diagrams and illustrations, used Braunschweig’s book as a resource.• A French scientist in the early 1800s who developed modern process techniques

called feed preheating and reflux.• Aeneas Coffey, who was issued a British patent in 1830 for his continuous-operated

distillation column (for whisky).• Ernest Solvay, who was granted a U.S. patent for a trayed ammonia distillation

column in 1877.

During the distillation process, hydrocarbon feed is stored in a feed tank. Before the feed is sentto the column, it is tested to ensure that it meets quality specifications. Some blending may occurat this point to ensure feed uniformity. Before the charge can be sent to the column, it must beheated up to operating temperatures. This part of the process involves sending the feed througha series of heat exchangers or a fired furnace. Feedstock temperatures are gradually stepped upas the flow moves through the system.

As the heated charge leaves the furnace and enters the distillation column, a fraction of the feedvaporizes and rises up the column, while the heavier components (still in liquid state) drop downthe column. This initiates the process of separation by boiling point. Because the energy in theprocess stream begins to dissipate immediately, a reboiler or heating source is attached to thecolumn. This allows the separation process to continue. Some distillation columns are steamtraced to ensure even temperature control.

The distillation process is represented by four distinct systems and one super system:• Utilities super system—boiler system, compressor systems, cooling-tower system,

electrical system, water system• Feed system—tanks, piping, valves, pumps• Preheating and heating system—heat exchangers and furnace• Process—distillation column or reactor, for example• Products system—tanks, piping, valves, pumps

Figure 10–4 illustrates the complexity of a distillation system.

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231

Figure 10–4 Multivariable Unit

Hot OilTank

T

To Flare

To Flare

Pump Pump

Pump

Pump

Pump

Pump

Pump

Pump

Pump

Pump

Tank

FeedTank

Tank

Tank

Tank

Cooling Tower

o

o FO

Furnace

KettleReboiler

HeatExchanger

Condenser

Drum

DistillationColumn

StirredReactor

Separator

o

Deaerator

Boiler

Compressor(Multi-Stage)

Dryers

Receiver

Air Header

Steam

Airinlet

AT

Ti

Pi

START

Ti

Ti

Fi

Ti

Ti

Ti

Pi

Pi

Ti

AT Pi Fi

DPT

AT

AT Fi

Ti

Fi

AIC

Pi

Fi

232


Figure 10–5 Absorption and Stripping Column

Steam

Rich Oil

Lean Gas

Rich Gas

Lean Oil

ABSORPTIONCOLUMN

STRIPPINGCOLUMN

Product

The liquid phase removes lighter components from the vapor phase. One direction component removal.

Reverses absorption process.Strips out hydrocarbons from

absorption oil.

Absorption, Stripping, and Scrubbing ColumnsAn absorber column is a device used to remove selected components from a gas stream by con-tacting the stream with a gas or liquid. A typical gas absorber is a plate distillation column orpacked distillation column that ensures intimate contact between raw natural gas and an ab-sorption medium. Absorption can roughly be compared to fractionation, although absorptioncolumns work differently than typical fractionators because during the process the vapor and liq-uid do not vaporize to any degree.

Figure 10–5 illustrates the scientific principles involved in absorption. Product exchange takesplace in one direction, vapor phase to liquid phase. The absorption oil gently tugs the pentanes,butanes, and so on out of the vapor. In an absorber, the gas is brought into the bottom of the col-umn while lean oil is pumped into the top of the column. As the lean oil moves down the column,it absorbs elements from the rich gas. As the raw, rich gas moves up the column, it is robbed ofspecific hydrocarbons and exits as lean gas.

Stripping columns are used with absorption columns to remove liquid hydrocarbons from the ab-sorption oil.To the untrained eye, stripping and absorption columns are identical. As rich oil leavesthe bottom of the absorber, it is pumped into the midsection of a stripping column. Figure 10–5illustrates how steam is injected directly into the bottom of the stripper, allowing for 100% conver-sion of Btus. As the hydrocarbons break free from the absorption oil, they move up the column,while the lean oil is recycled back to the absorber.


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Figure 10–6 Adsorption System

Packed TowerActivated Alumina or Charcoal

Stripping GasStripping Gas

AdsorptionDuring the adsorption process, a device (reactor, dryer, etc.) is filled with a porous solid designedto remove gases or liquids from a mixture. Typically the process is run in parallel with a primaryand secondary vessel. The adsorber can be activated alumina or charcoal. A variety of adsorp-tion materials can be used. The adsorption material has selective properties that will remove spe-cific components of the mixture as it passes over the adsorber. A stripping gas is used to removethe stripped components from the adsorption material.

During the adsorption process, the mixture to be separated is passed over the fixed-bed medium(adsorbent) in the primary device. Figure 10–6 illustrates this process. At the conclusion of the cy-cle, the process flow is transferred to the secondary device; then a stripping gas is admitted intothe primary device. The stripping gas is designed to remove or separate the selected chemicalfrom the adsorption material. At the end of this cycle, the stripping gas stops as the processswitches back and repeats.

ScrubberA scrubber is a device used to remove chemicals and solids from process gases, to protect andenhance environmental quality. Scrubbers are cylindrical in shape and can be filled with packingmaterial or left empty. As dirty gases enter the lower section of a scrubber, they begin to rise. Asthese dirty vapors rise, they encounter a liquid chemical wash that is being sprayed downward. Asthe vapors and liquid come into contact, the undesirable products entrained in the stream are re-moved. As dirty materials are absorbed into the liquid medium, they fall to the bottom of the scrub-ber, where they are mechanically removed. Clean gases flow out the top of the scrubber and moveon for further processing. Figure 10–7 is an illustration of a simple scrubber.

Figure 10–8 Chemical Separations

Figure 10–7 Scrubber System

10.3 Separation System

Chemical separation (Figure 10–8) is an alternative to distillation. At the heart of a separationsystem is a separator, a device that is designed to separate two liquids from each other by densitydifferences. Typically, a solvent is introduced that will dissolve one of the components in the mix-ture, thereby enhancing the separation process. After the solvent is introduced into the feedstock,it is blended in and then allowed to layer out. The heavier solvent tends to drop to the bottom ofthe separator, because its density differs from that of the solute. As the solvent mixes with and dis-solves the solute, it reverses direction and sinks. This new material—the solvent-and-solutecombination—is called the extract. Meanwhile, the lighter material, free from the solute, rises tothe top and flows over the weir. The raffinate and extract are not soluble and will naturally layerout.This process actually changes the direction of the flow: Lighter materials float to the top, while

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Drain

BerlSaddlePacking

CausticSodaPump

Gas In

To Vent

Solvent

Feed

Raffinate

Extract

Figure 10–9 Chemical Separation System

10.4 Pressure Relief Equipment and Flare System

235

ATAT Pi

PiPi Pi

IP

PIC

PE

PT

IP

TIC

TE

TT IP

LE LTLT

LE LIC

IP

Separator

Feed

Light

LightHeavyLIC

TemperatureControl

Pump Pump

Fi

Fi

Pi

LCVLCV

the heavier component sinks to the bottom. A separator has a shell, a weir, a vapor cavity, a feedinlet, an extract pump, and a raffinate pump. In addition to this equipment, a separator systemincludes temperature, level, flow, pressure, and analytical control instrumentation; two differentoutlet points, with separate pump systems for the extract and raffinate; and storage facilities.Figure 10–9 shows the major equipment found in a separation process.

A number of key terms associated with separation include:• Liquid-liquid extraction—separates two materials in a chemical mixture by introducing

a third chemical that will dissolve one of the other two chemicals.• Feedstock—the original solution fed to the separator.• Layering out—a process in which two liquids that are not soluble separate naturally

from each other (layer out) over a specific time.• Solute—the material that is dissolved in the separation process.• Solvent—substance that is specifically designed to dissolve a certain chemical.

10.4 Pressure Relief Equipment and Flare System

Pressure relief equipment includes relief valves, safety valves, rupture discs, piping, drums, ventstacks, pressure indicators, pressure alarms, pressure control loops, and flare systems. Processequipment is typically rated for specific pressure and temperature ranges. Engineering specifications

allow equipment systems to run within these specified conditions. Pressure control devices aredesigned to ensure that these conditions and operating parameters are not exceeded.

Pressure relief devices can be placed on pumps, compressors, tanks, piping, reactors, distillationcolumns, refrigeration systems, and many other kinds of equipment. Many materials cannot be re-leased to the atmosphere. These types of chemicals can be recycled back to the system, or sentto a scrubber or flare system. The discharge from all safety valves, pressure relief regulators, andoperating vents and blowdown valves in hydrocarbon service is collected in a closed piping sys-tem and sent to a flare stack. Steam, air, and nitrogen vapors discharge to the atmosphere. Steamsafety valves discharge harmless gases through tail pipes at a safe distance above grade or abovethe nearest operating platform.

Flare systems are used to safely remove excess hydrocarbons from a variety of plant processes.Flare systems are connected by a complex network of pipes and headers to a knockout drum andflare. Governmental laws and regulations require the flare to be located a safe distance from theoperating units and populated areas. Figure 10–10 shows a diagram and photograph of a typicalflare system.

Flare systems are part of a plant’s safety system. Most process units are aligned to safety reliefvalves that lift when specified pressures are exceeded.These safety valves discharge into the flareheader. Unexpected process upsets are dumped to the flare system as a last course of action.A typical flare system includes:

• Flare—a long narrow pipe mounted vertically• Steam ring—mounted at the top of the flare; used to disperse hydrocarbon vapors• Ignition source—located at the top of the flare• Fan—mounted at the base of the flare and used for forced-draft operation• Knockout drum with water seal• Flare header

10.5 Plastics System

A simple plastics system includes equipment that performs extrusion, molding, casting, laminat-ing, and calendering (see Figure 10–11). Injection molding, compression molding, and blow mold-ing are processes that resemble the way we make waffles for breakfast: Molten polymer issqueezed into a mold to produce a product. Examples of products manufactured by this processinclude tableware, plastic toys, and baby bottles.

Extrusion is a process that takes molten polymer and squeezes it down a barrel. This process iscomparable to squeezing shampoo out of a plastic bottle. Examples of products made from theplastic pellets produced by extruders are: baby diapers, washing machine parts, and car parts.

The laminating process takes aluminum foil, paper, or cloth and coats it with melted resin. Thisprocess is similar to building a sandwich. Examples of laminated products include motherboardsand electronic circuits.

Casting is a process that most closely reflects baking a cake. Just like cake batter is poured intoa pan, molten polymer is poured into a mold. This process yields items such as eyeglass lenses.

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Figure 10–10 (a) Flare System

Figure 10–10 (b) Flare System


237

EnrichedFlare Gas

Flame Arrestor

Two-Speed Fan

Natural Gas

Seal Water and

Knockout Pot

Typical Flare

Figure 10–11 Plastics System

The last process, calendering, closely resembles spreading butter over hot pancakes. During thecalendering process, rollers spread molten resins over thin sheets of paper or cloth. Calenderingis used to make playing cards, for example.

The initial process for creating plastic is very complex. Plastic is made from synthetic resins. Theatoms that make up the molecules of synthetic resins are composed of carbon, hydrogen, oxygen,and nitrogen. Process technicians make synthetic resins by combining chemical compounds suchas ammonia, benzene, hexamethylenetetramine, or a variety of other hard-to-pronounce chemi-cals. The reaction that takes place creates synthetic links between molecules called monomers.

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Air System

FeedTank

Homogenizer

Scalping Box

Dryer

ClassifierPelletWaterSlurry

Die

Screen Pac

Extruder

GearBox

Desch Coupling

Main DriveMotor

PelletWater Water TankPelletizer Chamber

Blender

Blender

Feeders


239

Figure 10–12 Plastics Extruder

Melt Divert Valve

Melt DivertValve to Mat

Pelletizer

PelletWaterOut

Pellet Water In

Die

ScreenPack

Degas VentFeed In

From Homogenizer

Gearboxand Motor

This process creates long-chain molecules called polymers. Industrial manufacturers refer to thisprocess as polymerization.

Key elements found in a plastics system include:• Polymerization section—reactor, distillation• Feed and transfer section—valves, piping, tanks, solids feeders, compressor• Blending section—additive blenders, homogenizer• Extrusion section—extruder, pelletizer, pipes, valves, pumps• Drying section—dryer, classifier• Products section—solids feeders, compressor, pipes, valves, storage tanks• Packing and transportation section—bags, boxes, railroad, truck

An extruder is a complex device composed of a heated jacket, a set of screws or a single screw,a heated die, a large motor, a gearbox, and a pelletizer. The purpose of the extruder is to melt thepolypropylene granule mixture, quickly quench it, and cut it into small pellets that are easier to han-dle. In its granular form, the molecular weight distribution and swell are too broad; various addi-tives, such as peroxide, help narrow this down. Melting the granules encapsulates the additives inthe polypropylene. Customers will not accept raw granules because of the danger of dust explo-sions. Figure 10–12 illustrates a plastics extruder.

Solids feeders are composed of single or multiple screws that rotate inside a sleeve. Granulesand additives from the feed and additive tanks are conveyed to the homogenizer by the feed-ers. Most solids feeders are single screws that deliver solids at a specific rate. Granules leavethe feed tank continuously when the extruder is in operation. Figure 10–13 illustrates how asolids feeder operates.

Some solids feeders have a two-stage design that allows granules to drop into a variable-speedscrew mounted on a scale. From the scale, a constant-speed screw delivers granules to adischarge line. The speed of the first screw is adjusted to maintain a constant scale weight. Theresult is a feed that is constant by weight.

Figure 10–14 Classifier

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Scale

Second Stage

First Stage

Continuous Feeder

Variable Speed

FeedTank

Slide Valve

Figure 10–13 Solids Feeder

Pellet Slurry

Scalping Bars

Trash

Water

Filters

Pellet DivertValve

Classifier

Pellets

Dryer

Helix andScreen

Scrap Box

Scrap Pan

The classifier is a vibrating tub with screens in two stages that permit the desired size of pellets topass through. Larger pellets or clumps that have managed to pass through the scalping box areeliminated from the product flow here. Between the two screens is a cleaning kit that is used toprevent pellets from lodging in the individual holes of the classifier. Figure 10–14 shows what thisdevice looks like.

10.6 Refrigeration System

241

10.6 Refrigeration System

Heating and cooling are two important aspects of modern process control. Refrigeration systems(see Figure 10–15) are used to provide cooling to industrial applications like air conditioning.Refrigeration units are composed of:

• Compressor—high-pressure refrigeration gas• Heat exchanger–cooling tower combination• Receiver• Expansion valve—low-pressure refrigeration liquid• Heat exchanger (evaporator)—low-pressure refrigerant gas

In the refrigeration process, low-pressure refrigerant gas is drawn into a compressor, convertedinto high-pressure refrigeration gas, and pushed into a shell-and-tube heat exchanger. The com-pression process generates a tremendous amount of heat that must be removed by the ex-changer. During the cooling process, the gas condenses into liquid phase and is collected in areceiver.

From the receiver, the high-pressure liquid refrigerant is pushed through a small opening in anexpansion valve. As the liquid expands, it changes phase. Because the boiling point of the

Figure 10–15 (a) Two-Step Refrigeration System

High PressureLiquid Refrigerant

Low PressureLiquid Refrigerant

Rotary Screw Compressor

CondenserEvaporator

Expansion

Slide Valve

Oil Separator

High PressureGas Refrigerant

COLD

HOT1

2

3

4

242


INDUCED DRAFTCross Flow

Cooling Tower


Oil Separator

Plate andFrame Exchange

Ice Water Supply

Chilled Water

Ice Covered Tubes

Glycol

Evaporator

Condenser

High Pressure Gas (Refrigerant)

Thermal Storage Tank

Low Pressure Vapor

Low PressureLiquid Refrigerant

High PressureLiquid Refrigerant

Pump

Pump

To Fan Coil Units(Finned Coils)

Pump

Slide Valve1

2

3

Pump

COLD

Hot

High PressureGas (Refrigerant)

Expansion Device(Orifice)

4

Figure 10–15 (b) Two-Step Refrigeration System

refrigerant is low, a cooling effect occurs in the evaporator. As the low-pressure refrigerant leavesthe evaporator, it enters the suction side of the compressor and the process begins again.

10.7 Water Treatment System

Twenty years ago, the chemical processing industry pumped a tremendous amount of water outof the ground for industrial applications. This practice was stopped after it was discovered that asthe water table dropped, so did the surrounding countryside. The CPI now uses surface water formost industrial applications. Surface water is defined as water that is drawn in for industrial appli-cations from lakes, rivers, and oceans.

As water enters the plant, it is stored in large holding basins and allowed to settle out (Figure 10–16).A series of large pumps take suction off the basin and send water to a series of filters for additionalpurification. Chemicals are added to control pH and remove suspended or dissolved solids. Somefiltered water is sent to demineralizers for additional treatment to remove dissolved impurities.

Figure 10–16 Water Treatment System

Summary

243

Settling Basin

Pump

Filter

Cooling Tower

10.8 Utilities

Utility SystemA refinery or chemical plant is supported by a utility section that provides steam, air, nitrogen, nat-ural gas, water, cooling systems, compressed gases, and a variety of other things. In many facili-ties, water treatment and power distribution are located in the utility section. New technicians oftenget their first start in utilities.

Steam is generated in a boiler system. Compressed gases are brought in by truck, cylinder, orpipeline, or may be compressed on site using existing compressor systems. Surface water isbrought in and treated for industrial and domestic uses; this process includes filtering and dem-ineralizing. In the water treatment process, all of the sewers in the plant are directed toward theenvironmental control system. Rainwater and chemicals are carefully treated before being re-leased into the environment. Cooling towers control the temperature of industrial water used inheat exchanger systems. Electricity may be generated in house using boilers, turbines, and elec-tric generators, or may be purchased from local power companies. Electricity is stepped down andsent to local motor control centers located throughout the plant. Furnaces produce the steam toheat cooling-tower basins and to support hundreds of applications in the plant.

Process plants have utility sections that specialize in water treatment, steam generation, cooling,and gas compression. Process utilities are typically defined as water and compressed gases. Plantwater can be classified as boiler feed water, drinking water, firewater, cooling-tower water, potablewater, and wastewater. Compressed gases include air, nitrogen, hydrogen, chlorine, and others.

Summary

Reactors are used to combine raw materials, heat, pressure, and catalysts in the right proportions.Five reactor designs are commonly used in the chemical processing industry: stirred reactors,fixed-bed reactors, fluidized-bed reactors, tubular reactors, and furnace reactors. The basic com-ponents of a reactor include a shell, a heating or cooling device, two or more product inlet ports,and one outlet port. Critical process variables in reactor operation include temperature, pressure,concentration of reactants, catalysts, and time.

A distillation process consists of a complex arrangement of systems that includes cooling-towersystem, pump-and-feed system, preheat system, product storage system, compressed-airsystem, steam-generation system, and complex instrument control system. Distillation columnsseparate chemical mixtures by the boiling points of the mixture components. Distillation columnsare either plate or packed designs. Distillation was used long before the evolution of the modernchemical engineering discipline.

An absorber is used to remove selected components from a gas stream by contacting the streamwith a gas or liquid. Stripping columns are used with absorption columns to remove liquidhydrocarbons from the absorption oil. An adsorber is a device filled with a porous solid designedto remove gases and liquids from a mixture. A scrubber is used to protect and enhance environ-mental quality by removing chemicals and solids from process gases.

In contrast to distillation, which uses boiling point to separate chemicals, a separation system usesdensity differences to achieve the separation.

Pressure relief equipment includes relief valves, safety valves, rupture discs, piping, drums, ventstacks, pressure indicators, pressure alarms, pressure control loops, and flare systems. Pressurerelief devices can be placed on pumps, compressors, tanks, piping, reactors, distillation columns,refrigeration systems, and many other kinds of equipment. Materials that cannot be released tothe atmosphere are recycled back to the system, or sent to a scrubber or flare system. The dis-charge from pressure relief equipment is collected in a closed piping system and sent to a flarestack. Harmless gases are discharged at a safe distance from plant operations areas.

Flare systems are designed to safely burn excess hydrocarbons. A flare system is composed of aflare, knockout drum, flare header, fan (optional), steam line and steam ring, fuel line, and burner.A flare is a tall pipe located a specified distance from the facility.

An extruder is a complex device used in plastics plants. It is composed of a heated jacket, set ofscrews or screw, heated die, large motor, gearbox, and pelletizer.The extruder melts a polypropylenegranule mixture to encapsulate additives, quickly quenches it, and cuts it into small pellets that areeasier to handle. A simple plastics system includes equipment for extrusion, molding, casting, lami-nating, and calendering.

In the refrigeration process, low-pressure refrigerant gas is drawn into a compressor, converted intohigh-pressure refrigeration gas, and pushed into a shell-and-tube heat exchanger. The heat gener-ated by the compression process must be removed by the exchanger.During the cooling process, thegas condenses into liquid phase and is collected in a receiver. From the receiver, the high-pressureliquid refrigerant is pushed through a small opening in an expansion valve. As the liquid expands, itchanges phase and creates a cooling effect in the evaporator.The low-pressure refrigerant leaves theevaporator and enters the suction side of the compressor so the process can begin again.

The chemical processing industry uses surface water, drawn in from lakes, rivers, and oceans, formost industrial applications. As water enters the plant, it is stored in large holding basins and al-lowed to settle. A series of large pumps send water to a series of filters for additional purification.Chemicals are added to control pH and suspended or dissolved solids. Some filtered water is sentto demineralizers for additional treatment to remove dissolved impurities.

Process plants have utility sections that specialize in water treatment, steam generation, cooling,and gas compression.

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Chapter 10 Review Questions1. Describe how a distillation column works.

2. What is the primary function of a reactor?

3. Draw a simple flare system.

4. List the basic equipment found in a distillation system.

5. List the equipment found in utility systems.

6. Describe the basic equipment found in a stirred reactor system.

7. Describe the equipment found in an extrusion system.

8. Describe a scrubber’s primary function.

9. Compare and contrast an absorption column with an adsorption system.

10. List the basic equipment used in a refrigeration system.

11. List the basic equipment found in a water treatment system.

12. Describe the purpose and operation of a pressure relief system and flare system.

13. Describe how a refrigeration system works.

14. What kinds of systems are found in a plant’s utility section?

15. List the various sections found in a plastics plant.

Industrial ProcessesAfter studying this chapter, the student will be able to:

• Define terms related to common industrial processes.• Explain and contrast petrochemical processes.• Describe the benzene, BTX aromatics, and ethylbenzene processes.• Describe the ethylene glycols, mixed xylenes, and olefins processes.• Describe the paraxylene, polyethylene, and xylene isomerization processes.• Describe the alkylation and fluid catalytic cracking processes.• Describe hydrodesulfurization, hydrocracking, and fluid coking• Describe the catalytic reforming and crude distillation processes.

247

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Chapter 11 ● Industrial Processes

Key TermsAlkylation—uses a reactor to make one large molecule out of two small molecules.

Alkylation unit—uses a reactor filled with catalyst to cause a chemical reaction that producesthe desired product.

Catcracker—uses a fixed-bed catalyst to separate smaller hydrocarbons from larger ones.

Distillation tower—a series of stills arranged so the vapor and liquid products from each trayflow countercurrently to each other.

Fixed-bed reactor—device in which the fixed medium remains in place as raw materials passover it.

Fluid catalytic cracking—a process that uses a reactor to split large gas oil molecules intosmaller, more useful ones.

Fluid coking—a process that uses a reactor to scrape the bottom of the barrel and squeezelight products out of the residue.

Fluidized-bed reactor—suspends solids within the reactor by countercurrent flow of gas.Particle segregation occurs over time as heavier components fall to the bottom and lighter onesmove to the top.

Hydrocracking—uses a multistage reactor system to boost yields of gasoline from crude oil.

Hydrodesulfurization unit—sweetens products by removing sulfur.

Reactor—a device used to convert raw materials into useful products through chemical reac-tions. It combines raw materials, heat, pressure, and catalysts in the right proportions to ini-tiate reactions and form products.

Reboiler—a heat exchanger used to maintain the heat balance on a distillation tower.

Reformer—a reactor filled with a catalyst designed to break large molecules into smaller onesthrough chemical reactions that remove hydrogen atoms.

Regenerator—used to recycle or regenerate contaminated catalyst.

11.1 Common Industrial Processes

During World War I (1914 to 1918), oil production became as important as ammunition production.Oil was used to operate ships, airplanes, tanks, automobiles, motorcycles, and other motorizedequipment. As technology improved, so did farming techniques around the world:Tractor technologyand other motorized farming implements increased productivity.The increased productivity enabledby gasoline led to a new revenue-generating source for the government (the gas tax). Another by-product of gas production was asphalt.This new material enabled the federal government, along withstate and local authorities, to upgrade existing road systems and launch new road-building ventures.

During World War II (1939 to 1945), technology took a few more steps forward. New process equip-ment was tested on naval vessels, submarines, aircraft, and land vehicles and in communications.

American oil companies demonstrated the ability to adapt quickly to wartime needs, and endedup producing more than 80% of the aviation fuel used by the Allies. Huge quantities of oil and newspecialty chemicals were needed during the war. For example, butadiene was used to make syn-thetic rubber; toluene is a major ingredient in medicinal oils and the explosive TNT.The World War IIperiod saw significant improvements in the industrial processes of alkylation and catalytic crack-ing. These two processes greatly enhanced the production of high-octane aviation gasoline.

Postwar years saw another tremendous increase in oil consumption. Process technicians could eas-ily find lifelong jobs at many of the large refineries. In the early 1950s, a Humble Oil (now Exxon)company employee could get a car loan in the Baytown, Texas, area simply by showing the sales-person an employee badge. This experience was common in cities where oil refining, gas process-ing, and petrochemicals pumped huge amounts of money into the local economy.

From 1950 to 1972, the government continued to draft large numbers of process technicians intothe military. Most companies worked with employees who had been drafted and allowed them toreturn to their jobs after their tours of duty. Some companies counted an employee’s service timein the military as uninterrupted company service time. This group of employees greatly influencedthe development of the military-type environment found in the chemical processing industry.

Workforce Trends 1960–1980As the complexity of industrial processes increased, a significant change occurred in the make-upof the technical workforce. Starting in the 1960s and building into the 1970s, the chemical pro-cessing industry began to employ large numbers of engineers. As this fact became known, engi-neering programs around the United States began to draw students. Colleges started turning outrecord numbers of:

• Electrical engineers• Chemical engineers• Mechanical engineers• Petroleum engineers• Industrial engineers• Nuclear engineers

Engineers were employed in the chemical processing industry as technical support to the opera-tions groups. This relationship was not new; engineers, chemists, and technicians had worked to-gether as a team for many years. The increased numbers, however, were new.

Common ProcessesIndustrial processes fall into three basic groups: refining (19 processes), gas processing(15 processes), and petrochemical processing (40 processes). The oldest and best-establishedgroup is refining processing. The most common industrial processes in the refining and petro-chemical areas include:

Petrochemical Processes Refining Processes

Alkylbenzene, linear Alkylation (4)

Amines, methyl Benzene reduction

Ammonia (5) Benzene saturation

Benzene Catalytic reforming (3)

11.1 Common Industrial Processes

249

Petrochemical Processes (continued) Refining Processes (continued)

Bisphenol-A (2) Coking (4)

BTX aromatics (3) Cracking

Butadiene Catalytic

Butanediol, 1,4- Deep catalytic

Butyraldehyde, n and i Fluid catalytic (6)

Caprolactam Hydrocracking (6)

Cumene (3) Residual catalytic

Dimethyl terephthalate (2) Crude distillation

EDC via oxychlorination Deasphalting (3)

Ethanolamines Electrical desalting

Ethylbenzene (3) Ethers (7)

Ethylene (6) Hydrogenation

Ethylene glycols Hydrotreating (7)

Ethylene oxide Isomerization (6)

Formaldehyde Treating

Maleic anhydride Visbreaking (3)

Methanol (4)

Olefins (3)

Paraxylene (2)

Phenol (2)

Phthalic anhydride

Polycaproamide

Polyethylene (5)

Polyethylene terephthalate (PET)

Polyethylene, LDPE-EVA

Polypropylene (3)

Propylene (3)

PVC (suspension) (2)

Styrene (2)

Terephthalic acid

Urea

Vinyl chloride

Vinyl chloride monomer

Xylene isomerization

Xylene isomers

Xylenes, mixed

250


The numbers in parentheses indicate the number of registered processes or ways to manufacturethe chemical.

11.2 Petrochemical Processes

Gas processing springs directly from the refining process. Since 1960, rapid developments haveoccurred in the petrochemical area. Currently, there are hundreds of petrochemical processes,and many of them can be accomplished in more than one way. Petrochemical processes are farmore numerous than the basic core refinery processes. This chapter lists many of the primaryprocesses found throughout the country. A process technician working in ethylene productioncould have to deal with more than five different operational arrangements. In addition to newprocesses, a tremendous surge in the development of small, specialty chemical companies is an-ticipated in the next 10 to 20 years.

11.3 Benzene

The benzene process is designed to produce high-purity benzene and heavy aromatics from amixture of toluene and heavier aromatics (Figure 11–1). Heated hydrogen and feedstock are (1) passed over a special catalyst bed that reacts to form a mixture of benzene, unreacted toluene,xylene, and heavy aromatics.This mixture is (2) condensed in a drum and (3) stabilized. Stabilizedbottoms are sent to a fixed-bed clay treater for acid wash color specifications and then (4) distilledto separate benzene, xylenes, toluene, and C9� aromatics.

The yields are 99 mol% aromatic yield of fresh toluene. Typical production yields for xylenes andbenzene are:

Wt% Feedstock Benzene Xylene

Nonaromatics 3.2 2.3

Benzene 0 11.3

Toluene 47.3 0.7

11.3 Benzene

251

Furnace

Start

Benzene

Xylenes

Fuel Gas

C7 Aromatics

H2

Make-Up Recycle Hydrogen

Recycle Toluene and C9 aromatics

Figure 11–1 Benzene Process

C8 aromatics 49.5 0.3

C9� aromatics 0 85.4

100% 100%

Wt% Products

Benzene 75.7 36.9

C8 aromatics 0 37.7

11.4 BTX Aromatics

BTX aromatics (Figure 11–2) are derived using a process based on extractive distillation. Theprocess is designed to produce yields of benzene, toluene hydrogen, xylenes, and C5�. TheBTX process starts with a feedstock composed of paraffins 57%, naphthenes 37%, and aro-matics 6% being fed into a series of moving fluidized-bed reactors 1 through 4. The feed flowsdownward over the special catalyst bed and out the lower section of the number 1 reactor; theprocess is then repeated with reactors 2, 3, and 4. The catalyst and feed mixtures are designedto flow from reactors 1 through 4. Because solids and liquids have different flow characteristics,a unique gas-lift transfer process is required to move the solid catalyst from one reactor to thenext. The gas-lifted catalyst is “series-fed” into each reactor’s feed hopper until it reaches reac-tor 4. As the catalyst moves between reactors, it accumulates coke deposits. To eliminate thecoke deposits, the fourth reactor transfers the catalyst to a regenerator where the coke is re-moved.The regenerated catalyst is gas-lifted back to the feed-hopper section on reactor 1 wherethe process starts over.

252


Feed

Aromizate to Separator

Moving-BedReactors

1–4

1 2 3 4

CatalystGas-Lift System

H2, C5, Benzene, Toluene, Xylenes

Paraffins Naphthenes Aromatics

RX RX RX RX

START

Regenerator

Figure 11–2 BTX Aromatics Process

11.5 Ethylbenzene

One of the more common ways to manufacture ethylbenzene (Figure 11–3) is to use a fixed-bedreactor filled with a special catalyst, a series of distillation columns, and a special process for alky-lation of benzene/ethylene.

11.6 Ethylene Glycols

The raw feedstock for an ethylene glycols unit includes refined ethylene oxide and pure water. Amixture of ethylene oxide and recycled pure water is (1) pumped to a feed tank, where it is blendedand heated prior to being (2) sent to the glycol reactor. Residence times in the reactor are longenough to allow all of the ethylene oxide to react. After the reaction is complete, the water/glycolmixture is pumped to a multistage evaporator. A thermosyphon reboiler is used to maintain tem-perature on the column. A total of six glycol columns is utilized to purify and separate the variouscomponents of the process streams. The glycol/water mixture flows from one column to the next,encountering successively lower pressures in each column. The last four columns operate undera vacuum. The plant process is designed to produce purified monoethylene glycol (EB); however,a number of secondary products, such as triethylene glycol (TEG) and diethylene glycol (DEG),are also formed. Figure 11–4 illustrates the ethylene glycol process.

11.7 Mixed Xylenes

The mixed xylenes process (Figure 11–5) selectively converts toluene to high-purity benzene,mixed xylenes, C9� aromatics, and C5�. The feedstock is composed of dry toluene, C9 aromat-ics, and hydrogen-rich recycle gas. The raw feedstock is introduced to the unit by being passedthrough a heat exchanger and a fired heater, and into a reactor. Mixed xylenes and benzene areproduced during toluene disproportionation in the vapor phase. Products from the reactor arepumped to a separator where hydrogen-rich gas is recycled to the reactor and primary bottomproducts are pumped into a series of fractionation columns for product separation.

11.7 Mixed Xylenes

253

Start

Ethylene

Benzene

Alk

ylat

ion

Rea

ctor

Tran

salk

ylat

ion

Rea

ctor

Ben

zene

Col

umn

Eth

ylbe

nzen

e C

olum

n

PE

B C

olum

n

Heavy Ends

Polyethylbenzenes

Recycle

Benzene

EB

Figure 11–3 Ethylbenzene Process

Reactor Wt% Yields Feed Product

C5 and lighter 1.3

C9� aromatics 1.8

Benzene 19.8

Toluene 100 52.0

Ethylbenzene 0.6

m-Xylene 12.8

o-Xylene 5.4

p-Xylene 6.3

254


Start

Make-Up Water

Water Recycle

EO

Hydration Reactor

Figure 11–4 Ethylene Glycol Process

Furnace

CW

Steam

CW

Start

Toluene

H2

Reactor Separator

Stabilizer

To Fractionation System

Fuel System H2 Recycle

Figure 11–5 Mixed Xylenes Process

11.8 Olefins

Three processes are associated with production of olefins. One process is designed to convertnatural gas or raw methanol to ethylene, propylene, and butane. The second process is designedto produce isobutylene and isoamylene feedstocks from hydrocarbon feedstock. This material isused in production of ethers, polymerization, and linear olefins for alkylation.The third process se-lectively converts gas oil feedstocks into high-octane gasoline and distillate, and C2–C5 olefins.

11.9 Paraxylenes

The paraxylene process (Figure 11–6) takes mixed xylenes from reformers or steam crackers toproduce high-purity paraxylene. Feedstock is pumped to a feed rerun column that removes C9(and heavier) materials out the bottom and mixed xylenes out the top. The overhead product issent to a set of adsorption columns where paraxylene is removed and purified to 99.9%. A seriesof distillation columns is used to separate or recycle the rest of the products.

11.10 Polyethylene

A variety of polyethylene processes exist and are popular with industrial manufacturers (Figure 11–7).These applications can be used to produce high- or low-density polyethylene, linear polyethylene,or linear low-density polyethylene.

11.11 Xylene Isomerization

Xylene isomerization takes depleted paraxylene and orthoxylene streams from the paraxyleneunit and passes them over a dual fixed-bed catalyst. As the process flow moves through the re-actor and over the catalyst, it is combined with hydrogen-rich recycle gas.The upper section of thereactor is utilized for EB dealkylation, and the lower section is optimized for xylene isomerization.EB conversion rates are typically in excess of 65%, whereas paraxylene concentrations are typically102% greater than equilibrium.

11.11 Xylene Isomerization

255

Start

Single-StageCrystallizer

Feed

Pure p-Xylene

PX Unit

Heat

Cool

Figure 11–6 Paraxylene Process

11.12 Ethylene

Industrial manufacturers use six popular methods to produce ethylene. The Lummus method isused to produce more than 45% of the ethylene sold in the world. This process produces 99.95vol.% polymer-grade ethylene. Some of the by-products created during this process are propylene,butadiene-rich C4s, aromatic-rich C6–C8 pyrolysis gasoline, and pure-grade hydrogen.

11.13 Refining Processes

Industrial manufacturers use 19 common refining processes. Refining processes are typicallylinked to the large branches of the crude oil tree. The global economy has allowed the chemicalprocessing industry to diversify into a variety of business ventures. During the 1960s and 1970s,a large number of petrochemical processes were developed; each of these processes had its rootsin the refinery operation. The refining group has the oldest set of processes. Products from the re-finery are typically used as feedstocks for modern petrochemical processes.

11.14 Alkylation

Alkylation units take two small molecules of isobutane and olefin (propylene, butylenes, orpentylenes) and combine them into one large molecule of high-octane liquid called alkylate. Thisalkylation combining process (Figure 11–8) takes place inside a reactor filled with an acid cata-lyst. Alkylate is a superior antiknock product that is used in blending unleaded gasoline.

256


M

Nitrogen

Start

To Extruder

Purge Column

1

2

3

4

5

Catalyst

Fresh Diluent

Fractionator

Compressor

Flash Chamber

Recycle Diluent

Ethylene

Comonomer

M

M

Ethylene Recovery

Loop Reactors

Recycle

To Flare

Figure 11–7 Polyethylene Process

After the reaction, a number of products are formed that require further processing to separateand clean the desired chemical streams. A separator and an alkaline substance are used to re-move (strip) the acid. The stripped acid is sent back to the reactor, while the remaining reactorproducts are sent to a distillation tower. Alkylate, isobutane, and propane gas are fractionallyseparated in the tower. Isobutane is returned to the alkylation reactor for further processing. Alky-late is sent on to the gasoline blending unit.

11.15 Fluid Catalytic Cracking

When crude oil comes into a refinery, it is processed in an atmospheric pipe still. The side streamof the pipe still is rich with light gas oil. Fluid catalytic cracking units, or catcrackers, split thisgas oil into smaller, more useful molecules (Figure 11–9). Fluid catalytic cracking units use the fol-lowing equipment during operation:

• Catalyst regenerator• Reactor• Fractionating tower

During operation, gas oil enters the reactor and is mixed with a superheated powdered catalyst(the cat in catcracking). The term cracking is appropriate for this process because, duringvaporization, the molecules literally split; they are then sent to a fractionation tower for further pro-cessing. The chemical reaction between the catalyst and light gas oil produces a solid carbon(coke) deposit. This deposit forms on the powdered catalyst and deactivates it. The spent catalyst

11.15 Fluid Catalytic Cracking

257

PlateTower

PlateTower

Isobutaneand Propane

Alkylate

Propane

Isobutane

Acid Settler

Reactor

Olefin Feed (propylene, butylenes, or pentylenes)

Isobutaneand Refrigerant

Recycle to Reactor

Recycled Acid

HydrocarbonTreated

with Caustic

Figure 11–8 Alkylation

is drawn off and sent to the regenerator where the coke is burned off. Catalyst regeneration is acontinuous process during operation. In the fractionation tower, the light gas oil is separated intofive different cuts:

1. Cat-cracked gas2. Cat-cracked naphtha3. Cat-cracked heating oil4. Light gas oil5. Residue

11.16 Hydrodesulfurization

Crude oil is a mixture of hydrocarbons, clay, water, and sulfur. Some crude mixtures have higherconcentrations of sulfur than others; these mixtures are referred to as sour feed. Hydrodesulfur-ization (Figure 11–10) is a process used by industrial manufacturers to “sweeten” or remove thesulfur. Hydrodesulfurization units use the following equipment during operation:

• Fired heater• Separator• Reactor

During operation, sour feed is mixed with hydrogen and heated in a fired furnace.The heated mix-ture is sent to a reactor where the hydrogen combines with the sulfur to form hydrogen sulfide.When the temperature is lowered slightly, the sweet crude condenses, leaving the hydrogen sul-fide in a vapor state.This vapor-and-liquid mixture is sent to a separator where the low-sulfur sweet

258


PlateTower

Naphtha

Heating Oil

Light Gas Oil

Recycled Liquids

HeavyGas Oil

Coke CatalystRecycles toRegenerator

Gas Oil Mixeswith Powdered

Catalyst

RegeneratedCatalyst

Spent Catalyst

Cracked Molecules

Gas and Heatfor SteamProduction

Cracked Gas

Regenerator

Reactor

Figure 11–9 Catcracking

feed is removed. The hydrogen sulfide and hydrogen are sent for further processing during whichthe hydrogen is separated and returned to the original system.

11.17 Hydrocracking

Hydrocracking is a process that industrial manufacturers use to boost gasoline yields (seeFigure 11–11). The process splits heavy gas oil molecules into smaller, lighter molecules calledhydrocrackate. Hydrocracking units use the following equipment during operation:

• First- and second-stage reactors• Separator drum• Fractionating tower

The hydrocracking process mixes heavy gas oil feed with hydrogen before sending it to the first-stage reactor. The reactor is filled with a fixed bed of catalyst. As process flow moves from the topof the reactor to the bottom, the cracking reaction takes place. First-stage hydrocrackate is sent toa separator drum where the hydrogen is reclaimed and the hydrocrackate is moved to a fraction-ation tower. In the fractionation tower, the hydrocrackate is separated into five different cuts:

1. Butane2. Light hydrocrackate3. Heavy hydrocrackate4. Heating oil5. Heavy bottom

The heavy bottom is mixed with hydrogen and sent to the second-stage reactor for further pro-cessing. The second-stage reactor reclaims as much of the hydrocrackate as possible beforesending it to the separator and tower.

11.17 Hydrocracking

259

Charge Out

Low Sulfur Product

Reactor

Mixture ofHydrogenSulfide,

Hydrogen,and Product

Is Cooled

Feed with Sulfur

Recycled H2

Furnace

1 2 3 4

Separator

Figure 11–10 Hydrodesulfurization

11.18 Fluid Coking

Fluid coking (Figure 11–12) is a process used by industrial manufacturers to squeeze every lastuseful molecule out of heavy residues. Residue from other processes flows into a specially de-signed, high-temperature reactor. Light products vaporize and flow to a fractionation column. Theremaining material is sent to a burner where further processing takes place. The burner producesthree separate products:

1. Coker gas for use in the plant2. Product coke for sale3. Recycled coke for the reactors

11.19 Catalytic Reforming

The catalytic reforming process (Figure 11–13) utilizes refinery naphtha to produce high-octanereformate. The advanced design utilizes a set of four moving-bed reactors and one regenerator.The process is similar to that used for BTX aromatics.The design employs continuous catalyst re-generation, continuous liquid flow, and solid flow movements between reactors.

11.20 Crude Distillation

In a crude distillation process (Figure 11–14), the various fractions of crude oil are separated bytheir boiling points. During the distillation process, crude oil goes through a number of phases.Theinitial charge is heated and desalted. This heating process is gradual; the charge moves through

260


1st stage Reactor

andCatalyst

PlateTower

Hydrogen

Hydrogen

Heavy Bottom

2nd StageReactor

andCatalyst

LightHydrocrackate

HeavyHydrocrackate

Heating Oil

Butane

HeavyGasOil

H2 Recycle

Hydrogen

SeparatorDrum

Figure 11–11 Hydrocracking

a series of heat exchangers before it enters the fired furnace. In the furnace, the charge splits intoa number of passes that are combined when the feedstock exits the furnace. A typical inlettemperature for a fired furnace is 550°F; the outlet temperature varies between 675°F and 725°F.The heated charge is pumped to a distillation column where a fraction of the feed vaporizes andmoves up the column. (The distillation column incorporates a still-upon-a-still design.) Vapors riseup the column while liquids drop down. Molecular distribution is different on each tray in the distil-lation column. A typical distillation column has one feed line, one overhead line, one reflux line,

11.20 Crude Distillation

261

Liquid Products to Fractionation

Scrubber Separatesand Recycles

Heavy Hydrocarbonsfrom Light Gases

ResidueFeed

Burner

Coker Gas

ProductCoke

Air and SteamCoke to Burner

Hot Coke Recycled

Reactor

Figure 11–12 Fluid Coking

Reactor with Catalyst

Furnace

1 2 3 4

Heat Exchanger

Separator

High OctaneNaphtha

Hydrogen

RX

Figure 11–13 Reforming

four side streams, and one bottom line. Different products exit at each point on the column. Crudedistillation columns produce flash gas, light and heavy naphtha, kerosene, diesel, cracker feed,gas oils, and asphalt.

Summary

Industrial processes can be broken into three basic groups: refining (19 processes), gas process-ing (15 processes), and petrochemical processing (40 processes). The oldest and best estab-lished group is refining processing; gas processing springs directly from the refining process.During the past 30 to 40 years, the gas processing and petrochemical areas have experiencedrapid technological advances and significant workforce shifts.

The refining processes discussed in this chapter included alkylation, fluid catalytic cracking, hy-drodesulfurization, hydrocracking, fluid coking, catalytic reforming, and crude distillation. Alkyla-tion takes two small molecules of isobutane and olefin and combines them into one large moleculecalled alkylate. Fluid catalytic cracking uses a heated catalyst to break large gas oil molecules intosmaller ones.

Hydrodesulfurization removes sulfur from a process stream. Hydrocracking uses a multistage re-actor system to boost yields of gasoline from crude oil. Fluid coking is applied to heavy residuesto remove or break loose usable products. Catalytic reforming uses a reactor/catalyst approach tobreak hydrogen loose from high-octane naphtha. Crude distillation separates the various compo-nents in crude oil by their boiling points.

The petrochemical processes covered in this chapter include those that use or produce benzene,BTX aromatics, ethylbenzene, ethylene glycol, mixed xylenes, olefins, paraxylene, polyethylene,xylene isomerization, and ethylene. The benzene process uses heated hydrogen, toluene, andheavy aromatic feedstock to produce high-purity benzene and heavier aromatics by passing it overa fixed catalyst bed. The BTX aromatics process passes a feedstock composed of paraffin,napthenes, and aromatics through a series of fluidized-bed reactors. Ethylbenzene manufacturing

262


FeedTank

Furnace

Column

Reboiler

HeatExchanger

Figure 11–14 Crude Distillation

uses a fixed-bed reactor filled with catalyst, a feedstock of ethylene and benzene, and a series ofdistillation columns to produce product.

Ethylene glycol is commonly used as antifreeze in automobiles. The feedstock includes pure wa-ter and refined ethylene oxide. This system combines a blending feed tank, glycol reactor, and aseries of distillation columns. Olefin manufacturing includes three major processes: the first con-verts natural gas to ethylene, propylene, or butane; the second produces isobutylene and isoamy-lene from hydrocarbon feedstocks; the third converts gas oil feedstocks into high-octane gasoline,distillates, and C2–C5 olefins. Plastics manufacturing employs a number of polymer processesthat handle polyethylene, polypropylene, and butyl polymers.

Summary

263

264


Chapter 11 Review Questions1. What is the primary difference between petrochemical and refinery processes?

2. List the significant industry events that occurred between 1914 and 1960.

3. Describe the evolution of the refinery process to petrochemical processes.

4. Describe the benzene process.

5. Describe the BTX aromatics process.

6. Sketch the ethylbenzene process.

7. Describe ethylene glycols operations.

8. Describe mixed xylenes operations.

9. Describe olefins operations.

10. Describe the paraxylene process.

11. Draw a simple sketch of the polyethylene process.

12. Describe xylene isomerization operations.

13. Describe the ethylene process.

14. Explain the basic refining process.

15. Explain alkylation.

16. Describe fluid catalytic cracking, catalytic reforming, and hydrocracking.

17. Describe the hydrodesulfurization process.

18. Explain the principles of crude distillation.

19. Explain fluid coking.

Process TechnologyOperationsAfter studying this chapter, the student will be able to:

• Describe and operate the feed and preheat system.• Identify the basic components of the distillation system.• Describe and operate the overhead and bottom systems on the distillation

column.• Describe and control the various process variables in the distillation system.• Collect operational data and process samples.• Know and apply safety and quality control rules and procedures.• Use an operating procedure to start up and shut down the distillation process.• Establish setpoints on each control loop and monitor operation.• Work in a self-directed team.• Complete the post-job walk-through with the instructor.• Qualify to operate the pilot plant.• Troubleshoot and analyze operational problems on the pilot plant.

265

266

Chapter 12 ● Process Technology Operations

Key TermsFeed system—composed of a variety of equipment systems, including feed tanks, valves, piping,instruments, and pumps.

Process instruments—devices that control processes and provide information about pressure,temperature, levels, flow, and analytical variables.

Process Technology 3—Operations—a college-level course, designed to be the capstoneexperience, that includes all the elements covered in a process technology two-year degreeprogram.

Trainee—an unqualified technician recently assigned to an operating unit.

Trainer—a qualified technician assigned to mentor a trainee.

12.1 Overview of Process

Process technology programs include traditional coursework and hands-on training.Theory coursescover safety, quality, process equipment, physics, chemistry, and instrumentation. The hands-oncomponent emphasizes process systems, troubleshooting, and operations. These classes includeconsole training, bench-top operations, and pilot plant operations.

Process Technology 3—Operations is a college-level course designed to be a hands-on expe-rience. This course includes all the elements covered in a process technology two-year degreeprogram and may be used as the capstone experience of that program. The pilot plant equipmentand systems will vary from one college to the next. Donations from local industry and grants aretypically used to purchase or secure expensive process equipment. Although the equipment andsystems available to each college are different, the objectives remain constant: The goal of theseprograms is to prepare graduates to take entry-level positions in the chemical processing indus-try. Technicians should consider this class to be the single most important course they will takeprior to entering the workforce.

12.2 Pilot Plant Operations

This chapter is an overview of a simple distillation process used by a number of educational pro-grams to teach operations. Primary equipment and systems are designed to simulate this process.Trainers usually require that new trainees receive an overview of the pilot plant process.

The feedstock simulated in this process is a binary mixture of butane (40%) and pentane(60%). Most educational programs use propylene glycol, water, or red dye to simulate these feedmixtures. Flow rates are controlled to the distillation column at 200 gallons per minute (gpm) orhour (gph).

Three butane analyzers are located on the unit to analyze the feed, overhead stream, and bottomstream. Feed-tank levels are controlled at 50% by level control loops. The distillation column

separates the components in the mixture by boiling point; however, some overlap of the butaneand pentane still takes place in both the overhead and bottom streams.

The distillation column has an enriching or rectifying section, a feed section, and a stripping sec-tion. A distillation system, however, also includes a large assortment of equipment and systemsthat support the process: feed section, preheat section, distillation column, overhead section, bot-tom section, and product storage. The quality system provides the mathematical foundation thatstandardizes plant operations. A unit checklist is designed to collect a wide variety of operationalinformation.

Feed SystemThe feed system is composed of a variety of equipment systems, including feed tank, valves, pip-ing, instruments, and pumps. Inside the feed system, the composition of the feedstock is closelymonitored. Flow rates, pressures, temperatures, and levels are carefully maintained.

Figure 12–1 shows the basic equipment found in a distillation feed system. Compressed air ornitrogen systems are also used in the feed system. Nitrogen is an inert gas that provides protectionfrom fire or explosion. Compressed air is used to open, close, or throttle control valves. Basic instru-ment systems used in the feed system include indicators, control loops, recorders, and analyzers.

Preheat SystemBefore feed can be sent to the distillation column, it must be preheated to a temperature range thatwill allow the separation process to occur. The pilot plant uses heat exchanger 101 to heat up thefeed. Heating the feed initiates the distillation process, as the various components in the mixturerespond differently.

Figure 12–2 illustrates what the preheat system looks like on this unit. As the feed is heated, pres-sure increases inside the pipe as the lighter components attempt to escape from the liquid. (Heatincreases molecular movement within the liquid.) A temperature control loop maintains unit spec-ifications. As the heated feed exits the heat exchanger, a temperature element and transmittersend a signal to TIC 101. The controller compares the signal to the setpoint and makes adjust-ments to the temperature control valve. The control valve regulates the flow of hot oil through theheat exchanger. Pump 101 is a centrifugal pump designed to pump feed to the column throughthe tube side of heat exchanger 100.


267

FEED TANK PiPi

AT

P-101

TK-100

V-1V-2

V-3

V-4V-5

CV-10

Figure 12–1 Distillation Feed System

Distillation ColumnAfter the feed has been blended and preheated, it is sent to the distillation column (see Figure 12–3).A flow control loop regulates the flow of feed at 200 gallons per minute.An orifice plate and flow trans-mitter send a signal to FIC 100. The controller compares this signal to the setpoint and adjusts thefeed by opening or closing control valve 10. In a plate column, the heated feed enters on the feedtray. The part of the column above the feed line is called the rectifying or enriching section. The partof the distillation column below the feed line is referred to as the stripping section. As the heated feedenters the column, part of it vaporizes and moves up the column. The heavier part of the mixtureflows down the column through devices called downcomers.

Each tray in the column forms a liquid seal that provides good vapor–liquid contact. Theoretically,each tray in the column would have a different molecular structure, ranging from heavier compo-nents in the bottom to lighter components in the top.The lighter fractions exert a higher vapor pres-sure. Typically, the temperatures are higher in the bottom of the column and lower at the top. Thisis referred to as a temperature gradient.

Two scientific principles must be balanced on a distillation column: energy and mass. Heat isreturned to the system using a kettle reboiler connected to the bottom of the distillation column.(A reboiler is a heat transfer device designed to add energy to the bottom fractions.) The heavierbottom product is still rich with lighter components that need help breaking free from the larger mol-ecules. As the heated fluid passes through the reboiler, the lighter components vaporize and flowinto the column under the bottom tray.The space below the bottom tray allows the liquid to free-rolland boil.

As feed flows into the column through a single feed source, the rate is carefully monitored. Thevarious fractions in the mixture can flow out the overhead, side, or bottom. The old saying that“what flows into the column must flow out ” is still true.

268


FT

FICI/P

TiPi

TE

TICI/P101

FlowTE

Pi

HOT OIL IN

HOT OIL OUT

278°F

350°F

Ti

185°F 25 psi 23 psi200 gpm

P-101

EX-100

100

CV-10

CV-9

Figure 12–2 Preheat System

The overhead system is specifically designed to condense the lighter fractions and send them to product storage and back to the top tray in the column. The cooled, condensed prod-uct that flows back to the column is called reflux. The system is specifically designed to controlproduct purity and control temperature in the top of the column. The overhead system includesa condenser, accumulator, pump, and piping. Figure 12–4 shows an overhead system.

The bottom product is sent to the tank farm for storage. (Figure 12–5 shows a bottom system.) Thetank farm has a number of product and off-spec tanks. The overhead stream is sent to the tankfarm, tested, and—if approved—shipped to the customer.

Variations in Feed CompositionIn a binary mixture, two components are separated from the feedstock. In this example, our distil-lation system has a 40/60 mixture of butane (water) and pentane (propylene glycol and red dye).Three butane analyzers are used to monitor the concentration of butane in the various streams.


269

DistillationColumn

Flow

ATAT

AT

Heat Exchanger(Overhead Condenser)

Kettle Reboiler

Feed Analyzer #1 Feed Analyzer #2

Feed Analyzer #3

OverheadAccumulatorReflux

SteamIn

Hot Vapor

EX-101

EX-102

D-100

C-100

P-103

FIC

FIC

FT

I/P100

TIC

LIC

TIC

LIC

FIC

FIC

PIC

P-104To

Boiler

Flare

Feed Tray

StrippingSection

EnrichingSection

Ti

Ti

Ti

Fi

Fi

Pi

Pi

Pi

Pi

Pi

Pi

100

100

102

102

Tray 1

Tray 2

Tray 4

Tray 5

Tray 6

Tray 7

Tray 8

CV-10

CV-11

CV-12

CV-13CV-14

CV-15

CV-16

Figure 12–3 Distillation Column

Feed composition, overhead product, and bottom product should be found in the followingconcentrations:

Overhead 98.5% butane, 1.5% pentane

Bottom 8% butane, 92% pentane

Feedstock 40% butane, 60% pentane

270


Heat Exchanger

I/P

FT

FIC

Fi

PVSPOP%

TE TT

TIC

AT2

I/P

FT

FIC

I/P

LTLIC

LE

Fi

PVSPOP%

Level Controller

Flow Controller

PVSPOP%

Temp/Controller

PVSPOP%

Flow Controller

PIC I/P

PE

PT

PVSPOP%

Pressure Controller

(Overhead Condenser)

Tray 8

Tray 7

Tray 6

Tray 5

Tray 4

D-100

P-103

101

103

102

400

100

130

50

160

105

102

Figure 12–4 Overhead System

Variations in product composition are carefully monitored and controlled. To do this, a variety ofmodern control features are incorporated into the system, including temperature, pressure, level,and flow control loops. Product variation is the enemy of any chemical process. When productspecifications are not met, customers will take their business elsewhere.

Data CollectionData collection gathers information about feed composition, overhead purity, and bottom purity.Three analyzers are placed in each of these streams to allow each process technician on shift tomonitor and record the process. Figure 12–6 shows information collected from the overhead line.In addition to the product lines, data is collected continuously on each control loop, and alarms arelocated on key equipment. A unit checklist is filled out during every shift as part of the data col-lection process concerning unit variables.

Control ChartsControlling the overhead butane concentration is an important quality aspect of processcontrol on a distillation system. This is accomplished by carefully monitoring the analyzer onthe overhead reflux stream and recording the lab results from each shift. The three daily


271

KettleReboiler

P-104

I/P

FT

FIC

PVSPOP%

PVSPOP%

Flow Controller

I/P

LT

LIC

LE

Fi

PVSPOP%

Level Controller

TE TT

TIC

Temperature Controller

SteamIn

ToBoiler

BottomProduct

Hot Vapor

103

50

Tray 1

Tray 2

Tray 3

Tray 4104

12

220

102

C-100

Figure 12–5 Bottom System

results are averaged and included on the control chart. The range is calculated by subtractingthe lowest reading from the highest. Using the equations for the X-bar chart (Figure 12–7) andthe R-bar chart (Figure 12–8), the upper and lower control limits can be calculated. Theaverage of the three daily results and the range between the variables allow us to developthe control chart.

12.3 Process Control Instrumentation

A number of variables in a distillation process are controlled by the process instruments, in-cluding pressure, temperature, level, flow, and analytical variables. The composition of theoverhead stream is only one of a large number of variables. The three analyzers on the unitare primary targets for a quality system. Figure 12–9 shows the typical variables found on thissystem.

272


Sample Date Flow (gpm) ∑X X-Bar RX1 X2 X3

1. 5-1-06 98.6 98.7 99 296 98.76 .4

2. 5-2-06 99.1 98.7 98.5 296 98.76 .6

3. 5-3-06 98.3 98.6 99.1 296 98.66 .8

4. 5-4-06 99 98.7 98.2 295 98.63 .8

5. 5-5-06 97.8 97.5 98 293 97.77 .5

6. 5-6-06 98.3 98 98.8 295 98.37 .8

7. 5-7-06 96.9 97.5 98.1 292 97.5 1.2

8. 5-8-06 97.8 98.4 98.6 295 98.26 .8

9. 5-9-06 99 99.1 98.7 297 98.93 .7

10. 5-10-06 97.9 98.1 98.6 295 98.2 .7

11. 5-11-06 98.1 98.5 99.2 296 98.6 1.1

12. 5-12-06 98.3 98.8 99 296 98.7 .7

98.43 .758

Figure 12–6 Distillation—Overhead Purity

X ChartUCL � X-bar � (A2 � R) 98.43 � (1.023 � .758) � 99.2LCL � X-bar � (A2 � R) 98.43 � (1.023 � .758) � 97.66

Range ChartUCL � R � D4 .758 � 2.575 � 1.95LCL � R � D3 .758 � 0 � 0


273

Figure 12–7 Butane Overhead Control X-Bar Chart

Figure 12–8 Butane Overhead Control R-Bar Chart

99.46

99.2

98.95

98.69

98.43

98.17

97.9

97.66

97.40

97.14

Target

% of Butane in Reflux

0 12Sample

X = 98.43

UCLX

LCLX

= 99.2

= 97.66

108642

2.0

1.8

1.6

1.4

1.2

1.0

0.8

0.6

0.4

Range

Sample

Target R = 0.758

UCLR

LCLR

= 1.95

0 12108642

= 0

12.4 Safety and Quality Control

Pilot plant operation includes specialized studies in all areas of safety training. This includes wear-ing personal protective equipment, reviewing a chemical inventory list, and discussing safe handlingand transportation of products. Hazards associated with heat, temperature, and pressure are care-fully reviewed with new technicians. There are a number of general safety rules for the pilot plant.Permit systems are designed to protect workers from hazardous energy, hot work, opening andblinding, confined-space entry, and cold work. A good permit system can easily be integrated intonormal operations to protect employees, equipment, and the environment.

The key to preventing catastrophic emergencies inside the pilot plant is adequate technician train-ing. The employee training aspect of the program includes the following sections:

• Process overview• Training records• Identification of chemicals used in the process• Control of access to and from the process unit• Training materials that reflect current work practices

274


Tag# Description Setpoint

AT-1 Butane Feed Analyzer 40%

AT-2 Butane Overhead Analyzer 98.5%

AT-3 Butane Bottom Analyzer 8%

TIC-101 Preheater Hot Oil 278°F

TIC-102 Column Bottom Tray #1 220°F

TIC-103 Column Top Tray #8 160°F

PIC-101 Column Top Pressure 100 psig

FIC-100 Unit Feed 200 gpm

FIC-102 Reflux Flow Rate 130 gpm

FIC-103 Bottom Flow Rate 135 gpm

FIC-104 Steam to Reboiler 12 mlb/hr

FIC-105 Cooling Water to Overhead Condenser 400 gpm

FI-102B Overhead Flow to Tank Farm 65 gpm

LIC-101 Feed Tank Level 50%

LIC-102 Overhead Accumulator Level 50%

LIC-103 Reboiler Level 50%

LIC All Product Tank Levels 50%

Figure 12–9 Distillation—Typical Process Variables

General safety rules are designed to protect human life, the environment, and physical equipmentor facilities. Before entering the pilot plant, a simple overview of the general plant safety rules isconducted. These rules include:

1. Respond to a fire, explosion, accident, or vapor release.2. Obey all college traffic rules.3. Do not park in designated fire lanes.4. Report injuries to the instructor immediately.5. Stay clear of suspended loads.6. Smoking and matches are not permitted in the pilot plant.7. Drink only from designated water fountains and potable water outlets.8. Use the right tool for the right job.9. Report to the designated equipment owner before entering an operating area. Stay in your

assigned area.10. Illegal drugs and alcohol are not permitted in the plant.11. Firearms are not allowed in the plant.12. Take steps to remove hazardous conditions.13. Review and follow all safety rules and procedures, including:

• personal protective equipment• hazard communication• respiratory protection• permit system• hazardous waste operations and emergency response• housekeeping• fire prevention

14. Know and understand the alarms and rules associated with:• vapor release• fire or explosion• evacuation• all clear

Statistical process control (SPC) allows a process to operate within its own variation by makingadjustments only after a number of samples have been taken (caught). The quality system on thepilot unit is linked to the customer’s specifications on the overhead and bottom streams.

Data Collection and Data OrganizationA large number of operating variables are checked each shift.These variables include, at the least,pressure, temperature, level, flow, and compositional data. Each variable is checked to see if it iswithin operational specifications. This data is carefully organized using a variety of quality toolsand techniques, including:

• Flowchart of start-up and operation• Checksheet for variables• Scatter diagram comparing overhead and bottom or feed• Histogram on product data (variation)• Run chart on temperature data—upper/lower• Control chart for color, and X-bar and R-bar charts

12.4 Safety and Quality Control

275

Analyzing the DataData analysis is a continuous process that process technicians carefully monitor. The followingquestions should help:

• What is the purity of the overhead stream?• What is the purity of the bottom stream?• What is the feed composition?• What is the energy output on the reboiler?• What is the energy output on the hot oil system?• Do product flow rates match operational and customer expectations?• Are pressure readings on pumps and equipment within guidelines?• Was the quality different at start-up? If so, did it improve or worsen?• Can the purity be controlled using the X-bar/R-chart system?

12.5 Bench-Top Operations

The pilot plant is supported by a bench-top unit designed to simulate actual operation. The glassdistillation unit includes most of the key equipment found on the unit. Figure 12–10 illustrates whata simple bench-top unit might look like. The process flow diagram (PFD) includes: operationaldata, such as how many milliliters (mL) the three-neck flask holds; measurements of the unit;average flow rate for the overhead line, measured in minutes; temperature scale in degreesFahrenheit or Celsius; feedstock composition; quantity; and so on.

12.6 Operating Procedures

Writing operational procedures is a process that uses the expertise of the equipment manufactur-ers, engineers, and operating staff.Typically, action words are used to identify each step of the pro-cedure. A start-up and shutdown procedure for each operating system should be written. Thisprocess documentation should be in place before the equipment is started. A start-up procedureis characterized by a series of action-related items:

• Collect 1,000 mL feedstock sample.• Ensure that area is clean.• Review safety procedure.• Check feedstock composition.• Pour feedstock into flask.• Take cold readings on bottom temp/top temp.• Set controller on 50%.• Review start-up procedure.• Ensure that unit is not dead-headed.• Turn on heating mantle and record time.• Catch temperature readings every five minutes.• Turn condenser on when upper temp reaches 150°F.• Record observations from visual checks of system.• Catch first overhead sample 10 minutes after upper temp reaches 210°F.

276


12.6 Operating Procedures

277

TI

DISTILLATIONEXPERIMENT

RedDye

Sample

VAPOR

LIQUID

VAPOR

PACKEDCOLUMN

CONDENSER

3 NECKFLASK

HEATINGMANTLE

VAPOR

LIQUID

TI

TC

Water InWaterOut

50%Max.

Collect Data

Organize Data

Analyze Data

—Pareto—Cause and effect

—Check sheets—PFD

—Scatter diagram—Histogram—Run chart

—Planned experimentation—TPM

TemperatureData

TemperatureData

Quality Data(COLOR)

Figure 12–10 Plate Distillation Column (Bench-Top Unit)

• Record quantity of upper sample.• Record temp delta between upper and lower and time lag between bottom and top

(i.e., how much time expired between the bottom boiling and top temperature movingto match).

• Composite overhead sample.• Catch fresh overhead sample.

The objective of experimental design in bench-top operations is to determine which variablesin the process or product are the critical parameters and their setpoint values. By using formalexperimental techniques, the effect of many variables can be studied at one time.

12.7 Self-Directed Work Teams

College operational classes have a limited amount of time to train and qualify technicians: between12 and 16 weeks. During the fourth or fifth week, new technicians take an assessment test on allequipment and technology associated with the pilot plant. This exam is designed for operationalshift placement. Before operating the unit, each technician spends hours tracing lines, identifyingequipment, preparing checklists, and developing start-up and shutdown procedures. A technicalnotebook is used to collect and organize all this material.

Immediately following the assessment exam, each operational shift is organized with a shift leader andlead operator.Each team is given specific operational assignments.The instructor initially assumes thetrainer role; however, this quickly changes as the team takes on more individual responsibility. Teamsare given more challenging operational assignments as they progress through the semester. Theinstructor makes careful observations of each team and carefully monitors individual work behaviors.

12.8 Walk-Through Qualification

Near the end of the semester, each new trainee is required to complete a unit walk-through withthe instructor. During this process, a standardized checklist is used to record each student’s levelof competency. At the final exam, trainees are required to draw and identify each part of the pilotunit. These exams are typically extensive and require significant effort, since operational andtroubleshooting data are included.The technical notebook reflects the sum of the student’s effortsduring the semester and is turned in on the last day.

Summary

Process technology programs include traditional coursework and hands-on training. Theorycourses cover safety, quality, process equipment, physics, chemistry, and instrumentation. Thehands-on component includes process systems, troubleshooting, and operations. These classesinclude console training, bench-top operations, and pilot plant operations. The goal of these pro-grams is to prepare graduates to take entry-level positions in the chemical processing industry.Process Technology 3—Operations is a college-level course designed to be the capstone experi-ence of a process technology two-year degree program.

278


A pilot unit includes feed section, preheat system, distillation column, overhead system, bottomsystem, and product storage.The feed system is composed of a variety of equipment systems, in-cluding feed tank, valves, piping, instruments, and pumps. Before feed can be sent to the distilla-tion column, it needs to be preheated using a heat exchanger.

After the feed has been blended and preheated, it is sent to the distillation column. In a plate col-umn, the heated feed enters on the feed tray. As the heated feed enters the column, part of itvaporizes and moves up the column. The heavier part of the mixture flows down the columnthrough devices called downcomers.

The overhead system is specifically designed to condense the lighter fractions and send them toproduct storage and back to the top tray in the column. The cooled, condensed product that flowsback to the column is called reflux. The system is specifically designed to control product purityand control temperature in the top of the column. The overhead system includes a condenser, ac-cumulator, pump, and piping.

The bottom product is sent to the tank farm for storage. The overhead stream is sent to the tankfarm, tested, and shipped to the customer.

A unit checklist is filled out on every shift as part of the data collection process regarding unit vari-ables. A large number of operating variables are checked each shift to see whether they are withinoperational specifications. These data are carefully organized using a variety of quality tools andtechniques, including flowcharts, checksheets, scatter diagrams, histograms, run charts, andcontrol charts.

New technicians take an assessment test on all equipment and technology associated with thepilot plant during the fourth or fifth week of a college operational class to determine operationalshift placement. Shifts are then organized with a shift leader and lead operator. Near the end ofthe semester, each new trainee is required to complete a unit walk-through with the instructor.Each student keeps a technical notebook throughout the semester in which information is collectedand organized; this notebook is turned in on the last day.

Summary

279

280


Chapter 12 Review Questions1. Describe the significance of the operations class.

2. Compare theory-related topics with the hands-on topics covered in the unit operationsclass.

3. Describe the feed and preheat systems.

4. Identify the major equipment found in the distillation system.

5. What is the primary difference between a trainer and a trainee?

6. Define the term bench-top operations and describe the purposes of a bench-top unit.

7. Explain the key elements covered on the assessment exam.

8. Explain the importance of operating procedures.

9. Describe the key elements of the walk-through qualification.

10. Describe the importance of control instrumentation in the pilot plant process.

Applied General ChemistryAfter studying this chapter, the student will be able to:

• Describe the fundamental principles of chemistry.• Define fundamental chemistry terms.• Describe and use chemical equations and the periodic table.• Describe these chemical reactions:

exothermicendothermicreplacementneutralizationcombustionheat and pressurecatalytic

• Perform a material balance.• Perform a percent-by-weight calculation.• Describe pH measurements.• Describe hydrocarbons.• Review applied concepts of chemical processing.

281

282

Chapter 13 ● Applied General Chemistry

Key TermsAcid—a chemical compound that has a pH value below 7.0, changes blue litmus to red, yieldshydrogen ions in water, and has a high concentration of hydrogen ions.

Atom—the smallest particle of a chemical element that still retains the properties of theelement. An atom is composed of protons and neutrons in a central nucleus surrounded byelectrons. Nearly all of an atom’s mass is located in the nucleus.

Atomic mass unit (AMU)—the sum of the masses in the nucleus of an atom.

Atomic number—identifies the position of the element on the periodic table and the totalnumber of protons in the atom.

Balanced equation—axiom that the sum of the reactants (atoms) equals the sum of the prod-ucts (atoms).

Base—a chemical compound that has a soapy feel and a pH value above 7.0. It turns red lit-mus paper blue and yields hydroxyl ions.

Catalyst—a chemical that can increase or decrease reaction rate without becoming part of theproduct.

Catcracking—a process designed to increase the yield of desirable products from a barrel ofcrude oil; uses a catalyst to accelerate the separation process.

Chemical bonding (covalent)—occurs when elements react with each other by sharing elec-trons. This forms an electrically neutral molecule.

Chemical bonding (ionic)—occurs when positively charged elements react with negativelycharged elements to form ionic bonds through the transfer of valence electrons. Ionic bondshave higher melting points and are held together by electrostatic attraction.

Chemical equation—numbers and symbols that represent a description of a chemical reaction.

Chemical reaction—a term used to describe the breaking, forming, or breaking and formingof chemical bonds. Types include exothermic, endothermic, replacement, and neutralization.

Chemistry—the science and laws that deal with the characteristics or structure of elementsand the changes that take place when elements combine to form other substances.

Combustion reaction—an exothermic reaction that requires fuel, oxygen, and heat to occur.In this type of reaction, oxygen reacts with another material so rapidly that fire is created.

Compound—a substance formed by the chemical combination of two or more substances indefinite proportions by weight.

Electron—a negatively charged particle that orbits the nucleus of an atom.

Element—matter composed of identical atoms.

Endothermic reaction—a reaction that requires external heat or energy to take place.

Exothermic reaction—a reaction that produces heat or energy.

Fractional distillation—a process that separates the components in a mixture by their indi-vidual boiling points.

Hydrocarbons—a class of chemical compounds that contain hydrogen and carbon.

Hydrogen ion—positively charged hydrogen particle.

Hydroxyl ion—negatively charged OH particle.

Ion—electrically charged atom.

Material balancing—a method for calculating reactant amounts versus product target rates.

Matter—anything that occupies space and has mass.

Mixture—composed of two or more substances that are only physically combined. Mixturescan be separated through physical means such as boiling or magnetic attraction.

Molecule—the smallest particle that retains the properties of the compound.

Neutralization reaction—a reaction designed to remove hydrogen ions or hydroxyl ions froma liquid.

Neutron—a neutral particle in the nucleus of an atom.

Percent-by-weight solution—representation in which the concentration of the solute isexpressed as a percentage of the total weight of the solution.

Periodic table—chart arranged by atomic number that provides information about all knownelements (e.g., atomic mass, symbol, atomic number, boiling point).

pH—a measurement system/scale used to determine the acidity or alkalinity of a solution.

Products—manufactured materials made from reactants combined in specific proportions.

Proton—a positively charged particle in the nucleus of an atom.

Reactants—raw materials that are combined in specific proportions to form finished products.

Reaction rate—the amount of time it takes a given amount of reactants to form a product.

Replacement reaction—a reaction designed to break a bond and form a new bond by replac-ing one or more of the components of the original compound.

Solute—the material dissolved in a solution.

Solution—a homogenous mixture.

13.1 Fundamental Principles of Chemistry

Chemistry is the study of the characteristics or structure of elements and the changes that takeplace when elements combine to form other substances. Process operators play a major role inthe production and manufacturing of finished products from raw materials. Modern chemistry is anessential part of the process environment and for this reason is a vital part in the initial training ofmost technicians.


283

Matter is anything that occupies space and has mass.The four physical states of matter are solid,liquid, gas, and plasma (the latter can be found in powerful magnetic fields).

ElementsThe purest form of matter is called an element. Elements cannot be broken down or changed bychemical or physical means. An element is composed of identical components called atoms. A listof all of the known elements, both natural and synthetic, can be found on the chemical elementchart (periodic table). The periodic table provides information about all known elements, such asatomic mass, symbol, atomic number, and boiling point.

AtomsAn atom is the smallest particle of an element that still retains the characteristics of that element.Atoms are composed of positively charged particles called protons, an equal number of neutralparticles called neutrons, and negatively charged particles called electrons (Figure 13–1). Pro-tons and neutrons make up the majority of the mass of an atom and reside in a central area re-ferred to as the nucleus. The sum of the masses in the nucleus (protons and neutrons) is calledthe atomic mass unit (AMU).

Atomic NumberThe atomic number of an element is determined by the number of protons in its nucleus. Theatomic number is used to locate the element in its proper place on the periodic table.

ElectronsOrbiting the nucleus are negatively charged particles known as electrons. Electrons and protonsare equally balanced in an atom. This is important because it ensures that each atom is electri-cally neutral.

Valence ElectronsThe electrons that reside in the outermost shell of an atom are referred to as valence elec-trons. Valence electrons are important to chemistry because they provide the links by which

284


PROTON

NEUTRON ELECTRON

+

N

CARBON ATOM

-++

+

++

NN

N+ N

NN

-

--

-

-

6 P, 6 N2 E4 E

Valence Shell

Valence Electrons

Nucleus

Shell

-

Figure 13–1 Carbon Atom

virtually every chemical reaction occurs. Atoms share their valence electrons to form chemicalbonds.

Chemical Bonding—Covalent and IonicThe two most common models for chemical bonding are covalent and ionic. Covalent bondsoccur when elements react with each other by sharing electrons.This forms an electrically neutralmolecule because the protons and electrons electrically balance each other.

If an atom has unequal numbers of protons or electrons, it is called an ion. Ions are electricallycharged atoms (positive or negative). Ionic chemical bonding occurs when positively chargedelements react with negatively charged elements to form ionic bonds through the sharing or lend-ing of electrons. Substances with ionic bonds have higher melting points and are held together byelectrostatic attraction.

Molecules and CompoundsCompounds are the products of chemical reactions (Figure 13–2). A compound is a substanceformed by the chemical combination of two or more substances in definite proportions by weight.A molecule is the smallest particle that retains the properties of the compound.

SolutionsSolutions are a type of homogenous mixture. The term homogenous signifies that the compo-nents of the solution are evenly mixed or distributed. A common example of a homogenous solu-tion is a drink mix. As the powdered drink substance is mixed with water, it becomes evenlydispersed throughout the water, creating a solution.

MixturesMixtures do not have a definite composition. A mixture is composed of two or more substancesthat are only mixed physically. Because a mixture is not chemically combined, it can be separatedthrough physical means, such as boiling or magnetic attraction.


285

WATERa covalent compound

-

++

+

++

NN

N+ N

N N

-

--

8 P, 8 N2 E6 E

-

OXYGEN ATOM

N+ +N

-H

-H

-

--

-

Figure 13–2 Compound

Crude oil is a simple example of a mixture (Figure 13–3). It is composed of hundreds of differenthydrocarbons. Process operators separate the different components in the crude oil by heating itto the boiling point in a distillation column.

13.2 Chemical Equations and the Periodic Table

The most common chemical substances are elements. Chemical elements are the buildingblocks of all substances. Each element is composed of atoms of only one kind. Chemistsdescribe elements with letters from the alphabet. The letter symbol for hydrogen is H. Theletter symbol for carbon is C (Figure 13–4). A periodic table or chemical element chart(Figure 13–5) lists all known chemical elements, with their symbols and other information.A good understanding of the chemical element chart helps a technician better understandchemical equations.

A chemical reaction can be described by associated numbers and symbols.The chemical numberidentifies how many protons are in an atom, and the atomic mass unit identifies how many unitsof an element are present.

286


High Octane Gas

Jet Fuel & Gasoline

Kerosene Diesel Oil

Heating Oil

Industrial Fuels

Waxes

Lubricating Oils

Greases

Asphalt

Treating Blending

Vapor Recovery Alkylation

Reforming

Catalytic Cracking

Solvent Extraction

Crystallization

Aromatic Recovery Treating

Blending

Treating Blending

Treating Blending

Treating Blending

Treating Blending

Feed

Petrochemicals

Petrochemicals

Figure 13–3 Crude Oil Distillation

In a chemical equation, the raw materials or reactants are placed on the left side. As the reac-tants are mixed together, they yield predictable products. A yield sign or arrow immediately followsthe reactants. The products are placed on the right side of the equation. Because atoms cannotbe created or destroyed, a common rule of thumb is “what goes into a chemical equation mustcome out.” The sum of the reactants must equal the sum of the products.

EXAMPLE:C � O2 (yields) CO2

1 carbon � 1 carbon2 oxygen � 2 oxygen(reactants) (products)


287

Figure 13–5 Periodic Table

C

6 12.011

CARBON

AtomicNumber

Symbol

Atomic Weight

Element

H

Li Be

Na Mg

K Ca

Rb Sr

Cs Ba

Fr Ra

Sc

Y

La

Ac

Ti

Zr

Hf

V

Nb

Ta

Cr

Mo

Re

Fe

Ru

Os

Co

Rh

Ir

Ni

Pd

Pt

Cu

Ag

Au

Zn

Cd

Hg

B

W

Mn

Al

Ga

In

TI

C

Si

Ge

Sn

Pb

N

P

As

Sb

Bi

O

S

Se

Te

Po

F

Cl

Br

I

At

He

Ne

Ar

Kr

Xe

Rn

Tc

Unq Unp Unh

1 1.0079

HYDROGEN

3 46.941 9.0126

LITHIUM BERYLLIUM

11 1222.99 24.30

SODIUM MAGNESIUM

19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36

37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54

55 56 57 72

87 88 89 104 105 106

73 74 75 76 77 78 79 80 81 82 83 84 85 86

2

5 6 7 8 9 10

13 14 15 16 17 18

10.81 12.01 14.006 15.99 18.99

26.98 28.08 30.97 32.06 35.45

20.18

4.002

39.94

39.09 40.08 44.95 47.9 50.94 51.99 54.93 55.84

POTASSIUM

RUBIDIUM

CESIUM

FRANCIUM

CALCIUM

STRONTIUM

BARLUM

RADIUM

87.62

137.33

226

SCANDIUM

VITRIUM

LANTHANUM

ACTINIUM

88.9

138.9

227

TITANIUM

ZIRCONIUM

HAFNIUM

91.22

178.4

VANADIUM

NIOBIUM

TANTALUM

92.9

180.9

CHROMIUM

MOLYBDENUM

TUNGSTEN

95.9

183

MANGANESE

TECHNETIUM

RHENIUM

98

186

IRON

RUTHENIUM

OSMIUM

101

190

58.93

COBALT

RHODIUM

IRIDIUM

102.9

192

58.7

NICKEL

PALLADIUM

PLATINUM

106.4

195

63.54

COPPER

SILVER

GOLD

107.8

196.9

65.38

ZINC

CADIUM

MERCURY

112.4

200.6

69.72

GALLIUM

INDIUM

THALLIUM

114.8

204.3

72.59

GERMANIUM

TIN

LEAD

118.6

207

74.92

ARSENIC

ANTIMONY

BISMUTH

121.7

208.9

78.96

SELENIUM

TELLURIUM

POLONIUM

127.6

209

79.90

BROMINE

IODINE

ASTATINE

126.9

210

83.8

KRYPTON

XENON

RADON

131.3

222

ALUMINUM SILICON PHOSPHORUS SULFUR CHLORINE ARGON

BORON CARBON NITROGEN OXYGEN FLUORINE NEON

HELIUM

85.46

132.90

223

GROUP1A

11A

111A 1VA VA V1A V11A V111A 1B 11B

111B 1VB VB V1B V11B

V111

Figure 13–4 Periodic Table Information Box

Remember, what goes in must come out!

Cu � H2SO4 CuSO4 � H2

1 copper 1 copper2 hydrogen 2 hydrogen

1 sulfur 1 sulfur4 oxygen 4 oxygen

4NH3 � 3O2 2N2 � 6H2O

4 nitrogen 4 nitrogen12 hydrogen 12 hydrogen

6 oxygen 6 oxygen

Mass Relationships—Chemical EquationsTo work out mass relationships, you need to have a good understanding of the chemical elementchart. Certain elements combine to form chemicals that you will recognize easily; for example,water (H2O) or carbon dioxide (CO2). The elements and atomic mass units are listed on theperiodic table.

EXAMPLE:

H3PO4 � 3NaOH Na3PO4 � 3H2O

Phosphoric acid and sodium hydroxide react to form sodium phosphate and water. What is theproduct’s total molecular weight?

Phosphoric acid (H3PO4) � 1 molecule (molecular weight?)Sodium hydroxide (NaOH) � 1 molecule (molecular weight?)

Sodium phosphate (Na3PO4) � 1 molecule (molecular weight?)Water (H2O) � 1 molecule (molecular weight?)

H3PO4—Reactant3 hydrogen � 3 � 1.008 AMU � 3.0241 phosphorus � 1 � 30.98 AMU � 30.984 oxygen � 4 � 16.00 AMU � 64.00

98.00 grams, pounds, or tons3NaOH—Reactant

3 sodium � 3 � 23.00 AMU � 69.003 oxygen � 3 � 16.00 AMU � 48.003 hydrogen � 3 � 1.008 AMU � 3.024

120.02 grams, pounds, or tons

98.00 � 120.02 � 218.02Reactant’s total molecular weight � 218 grams, pound, or tons

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Na3PO4—Product3 sodium � 3 � 23.00 AMU � 69.001 phosphorus � 1 � 30.98 AMU � 30.984 oxygen � 4 � 16.00 AMU � 64.00


3H2O—Product6 hydrogen � 6 � 1.008 AMU � 6.0483 oxygen � 3 � 16.00 AMU � 48.000


163.98 � 54.05 � 218.03Product’s total molecular weight � 218 grams, pounds, or tons

EXAMPLE:

4H2 � 2O2 4H2OFour volumes of hydrogen react with two volumes of oxygen to produce four volumes of water vapor.What is the product’s total molecular weight?

Hydrogen (2H2) � 1 molecule (molecular weight?)Oxygen (O2) � 1 molecule (molecular weight?)

2H2—Reactant8 hydrogen � 8 � 1.008 AMU � 8.064 grams, pounds, or tons

O2—Reactant4 oxygen � 4 � 16 AMU � 64.00 grams, pounds, or tons

8.064 � 64.00 � 72.064Reactant’s total molecular weight � 72.06 grams, pounds, or tons

4H2O—Product8 hydrogen � 8 � 1.008 AMU � 8.0644 oxygen � 4 � 16.00 AMU � 64.00


Product’s total molecular weight � 72.06 grams, pounds, or tons

Solve: Given the chemical equation:

H3PO4 � 3NaOH Na3PO4 � 3H2O18 tons 10 tons (28 total tons)

a. Change H3PO4 (18 tons) to 1,800 tons.b. What must the (3NaOH) weight be to balance the equation?


289

Solution: The first thing to remember in this type of problem is to identify the relative weight andthe actual weight. The relative weight in this problem is 1,800 tons. The actual weight is 18 tons.Now, divide the relative weight by the actual weight.

1,800 � 18 � 100

Use this new factor to adjust the 10 tons of 3NaOH.10 tons � 100 � 1,000 tons1,000 tons balances the 3NaOH equation.

Solve: Given the chemical equation:

H3PO4 � 3NaOH Na3PO4 � 3H2O

If you are told to add 25 lb of phosphoric acid (H3PO4) to the previous equation, how many poundsdo you need to add to the sodium hydroxide (NaOH) to keep the equation balanced?

Solution: The first thing to remember in this type of problem is to identify the relative weight andthe actual weight. The relative weight in this problem is 25 lb. The actual weight is the total AMUof H3PO4, which is 98 AMUs. (This can be in pounds or tons.)

Now, divide the relative weight by the actual weight.

25 � 98 � 0.255

H3PO4 (phosphoric acid) 3NaOH (sodium hydroxide)

H3 � 3 � 1.0079 � 3.0237 3Na � 3 � 23 � 69P � 1 � 31 � 31 3O � 3 � 16 � 48O4 � 4 � 16 � 64 3H � 3 � 1 � 3

TOTAL 98 TOTAL 120

Use this new factor to adjust the 120 AMUs of 3NaOH.0.255 � 120 � 30.6 lb30.6 lb balances the 3NaOH equation.

Solve:N2 � 3H2 2NH3

120 lb 39 lb 159 lb? lb ? lb 556 lb420 lb 136.5 lb

Solution: The relative weight is 556 lb. The actual is 159 lb.556 � 159 � 3.5

3.5 � 120 � 4203.5 � 39 � 136.5

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Solve:CH4 + 2O2 CO2 + 2H2O1,600 lb ? ? ?

Solution: The relative weight is 1,600 lb. The actual weight is CH4 (16 AMUs).

1C 1 � 12 � 12 4O2 4 � 16 � 64 1C 1 � 12 � 12 4H 4 � 1 � 44H 4 � 1 � 4 2O2 2 � 16 � 32 2O2 2 � 16 � 32

16 44 36

1,600 � 16 = 100

CH4 100 � 16 � 1,600 lb2O2 100 � 64 � 6,400 lbCO2 100 � 44 � 4,400 lb2H2O 100 � 36 � 3,600 lb

13.3 Chemical Reactions

ExothermicExothermic reactions are chemical reactions characterized by the liberation of heat. As thereaction rate increases, the evolution of heat energy increases. Exothermic reactions can bemoderated by controlling reactant flow rates, removing heat, or providing cooling.

EndothermicEndothermic reactions must absorb energy in order to proceed.

ReplacementIndustrial manufacturers use replacement reactions to remove dissolved mineral ions fromprocess water. A number of dissolved minerals can be found in process fluids; for example, acompound commonly found in process water is calcium chloride. Calcium chloride (CaCl2) formspositive calcium (Ca�) ions and negative chloride (Cl2

�) ions when it is dissolved in water.

A replacement reaction can remove the Ca� ions and the Cl2� ions using synthetic resins. Resins

are plastic strands rolled into balls and charged with ions. An H� ion on a resin ball is replaced by theCa� ion as the process fluid moves through the resin bed. The replacement reaction will take placeuntil all of the Ca� ions are removed from the fluid or the H� ions from the resin balls are used up.

Resin balls used for replacement reactions can be treated with either positively or negativelycharged ions. For example, resin balls charged with hydroxyl ions (OH�) can be used to replacethe chloride ion (Cl�).

NeutralizationNeutralization reactions remove hydrogen ions (acid) or hydroxyl ions (base) from a liquid.Neutralization reactions are designed to reduce or eliminate the acidity or alkalinity of a solution.Hydrogen ions (acid) and hydroxyl ions (base) neutralize each other.

13.3 Chemical Reactions

291

CombustionCombustion reactions are exothermic reactions that require fuel, oxygen, and heat to occur. Inthis type of reaction, oxygen reacts with another material so rapidly that fire is created. A fired fur-nace or a boiler is an example of a device that uses combustion reaction. Natural methane gas ispumped to the burner, mixed with oxygen, and ignited. This type of reaction can be representedby the following chemical equation:

CH4 � 2O2 CO2 � 2H2O

In this equation, one molecule of methane (CH4) chemically reacts with two molecules of oxygento produce one molecule of carbon dioxide and two molecules of water.

Heat and PressureFor a chemical reaction to occur, the atoms of the reactants must collide with each other. Theaddition of heat to a process increases reactant molecular activity.The addition of heat energy thusaffects a process by increasing molecular activity, increasing the number of atomic collisions, andenhancing the formation of chemical bonds. This increased activity ensures a much higher rateof energy transfer between molecules as they collide with each other. Reaction rates double withevery 10 degrees of heat added.

Note: High temperatures can cause undesirable products to form. Process temperatures areclosely monitored during operation to ensure smooth and efficient reaction rates.

Another important factor in a chemical reaction is pressure. Pressure has its greatest impact ongases, which are much easier to compress than liquids. Pressure can change the boiling point ofa liquid and slow down molecular activity. As pressure builds, it pushes the gas molecules closertogether and back into the liquid. More heat is required to boil the liquid, which wastes time andmoney. (See Figure 13–6.)

Reaction rates are affected by:

• Heat—molecular activity increases, atomic collisions increase, and the formation ofchemical bonds is enhanced

• Surface area—solids• Concentration—liquid and gas reactants• Pressure• Flow rates—reactants and products• Catalyst presence

CatalystA catalyst is a chemical that increases or decreases the reaction rate without becoming part ofthe product. Types of catalysts include:

• Adsorption-type catalyst—a solid that attracts and holds reactant molecules so that ahigher number of collisions can occur. It also stretches the bonds of the reactants itis holding, weakening the bonds so that less energy is required to break them andrebond.

292


• Intermediate-type catalyst—forms an intermediate product by attaching to thereactant and slowing it down so collisions can occur. This type of catalyst does not become part of the final product.

• Inhibitor-type catalyst—decreases reaction rate.• Poisoned catalyst—no longer functions; used up.

13.4 Material Balance

Material balancing is a method technicians use to determine the exact amount of reactantsneeded to produce the specified products.This method is used when two or more substances arecombined in a chemical process. Reactants must be mixed in the proper proportions to avoidwaste. Material balancing provides an operator with the correct reactant ratio.

The steps in checking a material balance are:

1. determine the weight of each molecule,2. ensure that reactant total weight is equal to product total weight, and3. determine relative numbers of reactant atoms or ions.

13.4 Material Balance

293

Heat Exchanger

Steam

Steam In

Feed

LT

400°F

HOT

Heat speeds up molecular activity.Pressure pushes molecules closer together.

150psig

150psig

150psig

400°F

Figure 13–6 Heat and Pressure

Relative and Actual Weights

Step 1 H� � OH� H2O Step 2 H� (1 AMU) � OH� (17 AMU) H2O (18 AMU)

Note: The relationship between AMUs and other units is 1 AMU � 1 gram, pound, or ton.

Step 3 H� (1 g) � OH� (17 g) H2O (18 g)Add 10 grams of hydrogen ions and balance the equation.

Step 4 H� (10 � 1 g) � OH� (10 � 17 g) H2O (? g)

Step 5 H� (10 g) � OH� (170 g) H2O (180 g)

EXAMPLE 1Solve:

Na2O � 2HOCl 2NaOCl � H2O

List the reactant elements. List the product elements. Is this chemical equation balanced?

Na2O � 2HOCl 2NaOCl � H2O2Na 2Na3O 3O2Cl 2Cl2H 2H

Yes, this chemical equation is a balanced equation.

EXAMPLE 2Solve:

2H3PO4 H2O � H4P2O8

List the reactant elements. Is this chemical equation balanced?

2H3PO4 H2O � H4P2O8

6H 6H2P 2P8O 9O

No, this chemical equation is not balanced.

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13.5 Percent-by-Weight Solutions

Percent-by-weight solutions are expressed as a percentage of the weight of the total solution.In other words, the weight of the solute (material being dissolved) is taken in relationship to theweight of the entire solution.

In a weight-percent problem, the amount of the solute and solvent can be calculated. For exam-ple, a 400-lb barrel has a 6% catalyst solution. The weight of the catalyst can be determined bymultiplying the weight of the solution by the percent of the solute.

Weight of Solution � Percent of Solute � Weight of Solute400 pounds � 6% or 0.06 � 24 lb

Figure 13–7 is an example of a solution.

13.6 Measurement of pH

The term pH refers to a measurement system used to determine the acidity or alkalinity of asolution. An acid is a chemical compound that has a pH value below 7.0. It changes blue litmusto red and yields hydrogen ions in water. An acid has a high concentration of hydrogen ions.

13.6 Measurement of pH

295

Condenser

Pump

Reboiler

HeatExchanger

Hot Vapor Line

Steam

Bottom

RECTIFYING

STRIPPING

BottomResidual

Vacuum Pump

FEED STOCK SOLUTIONA HOMOGENOUS MIXTURE

1

2

3

4

5

6

7

8

9

10

1. Methane 2. Ethane 3. Propane 4. Butane 5. Pentane 6. Hexane 7. Octane 8. Nonane 9. Decane10. Residue

LT

Figure 13–7 Solution

A base is a chemical compound that has a soapy feel and a pH value above 7.0. It turns red lit-mus paper blue and yields hydroxyl ions.

The methods for determining pH include:

• pH comparator—an indicator solution is added to the fluid to be checked. The color ofthe resulting solution is compared to the pH comparator standards.

• pH paper—red or blue litmus is impregnated with an indicator that causes a colorchange to occur in the presence of an acid or base.

• pH meter—directly measures the concentration of hydrogen ions in a solution.

13.7 Hydrocarbons

A hydrocarbon is a chemical compound that contains hydrogen and carbon. One of the best-known hydrocarbons is crude oil. Crude oil is a mixture of hydrocarbons that vary from simple tocomplex. Industrial manufacturers separate the various components of crude oil by boiling or dis-tilling it. The lighter carbon molecules have different boiling points than the heavier molecules.

The simplest hydrocarbon is methane or natural gas. Methane has one carbon atom and fourhydrogen atoms. Close examination of the atomic structure of methane indicates that the outervalence electrons tend to couple in pairs. Compounds made up of carbon atoms have four possiblebonds on each atom. The four arms (valence electrons) on each carbon atom bond with a hydro-gen or another carbon atom. Each slot on the carbon atom must be filled. There are millions ofpossible combinations for these carbon atoms. Chemists have divided these hydrocarbons intotwo very large families: alkanes and olefins.

AlkanesFigure 13–8 shows the composition of some alkanes.

The First 10 AlkanesName Molecular Formula

1. Methane CH4

2. Ethane C2H6

3. Propane C3H8

4. Butane C4H10

5. Pentane C5H12

6. Hexane C6H14

7. Heptane C7H16

8. Octane C8H18

9. Nonane C9H20

10. Decane C10H22

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13.7 Hydrocarbons

297

C

H

HH

HMethane

C

H

HH

HEthane

C

H

H

C

H

H

H

Propane

C

H

H

HC

H

H

C

H

H

H

n-Butane

C

H

H

HC

H

H

C

H

H

C

H

H

HPentane

C

H

H

C

H

H

C

H

H

HC

H

H

C

H

H

HHexane

C

H

H

C

H

H

C

H

H

HC

H

H

C

H

H

C

H

H

HHeptane

C

H

H

C

H

H

C

H

H

HC

H

H

C

H

H

C

H

H

C

H

H

HOctane

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

H

H

H

C

Figure 13–8 Alkanes

Chain Length Effects on Boiling PointMolecular Boiling

Alkane Structure Weight Point

Methane CH4 16 –164°C

Ethane CH3—CH3 30 –89°C

Propane CH3—CH2—CH3 44 –42°C

Butane CH3—CH2—CH2—CH3 58 –0.5°C

Pentane CH3—CH2—CH2—CH2—CH3 72 36°C

Hexane CH3—CH2—CH2—CH2—CH2—CH3 86 69°C

Heptane CH3—CH2—CH2—CH2—CH2—CH2—CH3 100 98°C

Octane CH3—CH2—CH2—CH2—CH2—CH2—CH2—CH3 114 126°C

Nonane CH3—CH2—CH2—CH2—CH2—CH2—CH2—CH2—CH3 128 151°C

Decane CH3—CH2—CH2—CH2—CH2—CH2—CH2—CH2—CH2—CH3 142 174°C

OlefinsOlefins (Figure 13–9) do not occur naturally in crude oil. Olefins are created by a manmadeprocess called cracking. Each molecule of an olefin has at least one double bond.

13.8 Applied Concepts in Chemical Processing

DistillationA number of fractions (components) are obtained from the distillation of petroleum. Distillation isdefined as the separation of the various fractions in a mixture by individual boiling points. Hydro-carbon fractions obtained from petroleum include straight-run gasoline, kerosene, heating oil,diesel, jet fuel, lubricating oil, paraffin wax, asphalt, and tar (Figure 13–10). Additional processescan be applied to these different fractions to create other products.

Boiling Range Carbons FractionBelow 200°C 4–12 straight-run gasoline150–275°C 10–14 kerosene175–350°C 12–20 heating oil, diesel, jet fuel350–550°C 20–36 lubricating oil, paraffin waxResidue 36+ asphalt, tar

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C

H

Ethylene

C

H

C

H

H

H

Propylene

C

H

C

H

H

C

H

H

Butylene

C

H

HC

H

H

C

H

H

H H

C2 H4 C3H6 C4 H8

BP = –155°F BP = –54°F BP = 21°F

C

H

H

Butadiene

C

H

C

H

C

H

H

C4 H6

Figure 13–9 Olefins

Feed

C1

C4 C12 Gasoline

C10 C14 Kerosene

C12 C20 Heating OilCRUDE

OILC20 C36 Lube Oil

C36 + Asphalt–Tar

C4 Gases

Figure 13–10 Hydrocarbon Fractions

A distillation tower is a series of stills placed one on top of the other. As vaporization occurs, thelighter components of the mixture move up the tower and are distributed on the various trays. Thelightest component goes out the top of the tower in a vapor state and is passed over the coolingcoils of a shell-and-tube condenser. As the hot vapor comes into contact with the coils, it con-denses and is collected in the overhead accumulator. Part of this product is sent to storage, whilethe rest is returned to the tower as reflux.

Heat balance on the tower is maintained by a device known as a reboiler. Reboilers take suctionoff the bottom of the tower. The heaviest components of the tower are pulled into the reboiler andstripped of smaller molecules.The stripped vapors are returned to the column and allowed to sep-arate in the tower.

ReactorsProcess technicians play a major role in the production and manufacturing of chemicals: They op-erate and maintain the systems that combine raw materials and modern reaction technology toform new products. The foundation upon which this industry rests is modern chemistry. As notedearlier in this chapter, chemistry is the study of the characteristics or structure of elements and thechanges that take place when they combine to form other substances. A reactor is designed tomake or break chemical bonds, thereby changing the molecular structure of raw materials. Inshort, a reactor is a device used to convert raw materials into useful products through chemicalreactions. Process operators are responsible for the safe and efficient operation of the reactor andits associated equipment.

Catalytic CrackingCrude oil comes into a refinery and is processed in a fractionating tower. The side stream of thecolumn is rich with light gas oil. Fluid catalytic cracking units split this gas oil into smaller, moreuseful molecules. Generally, only 20% of a barrel of crude oil can be used to produce gasoline.Fluid catalytic cracking is a process that uses a reactor to split large, covalent gas oil moleculesinto smaller, more useful ones. For instance, cracking a C12 kerosene molecule yields two C6 mol-ecules (hexane and hexene). Figure 13–11 illustrates this process.The catalytic process increasesyields from 20% to 50% by splitting the kerosene and heating oil fractions of the crude.

13.8 Applied Concepts in Chemical Processing

299

H - C - C - C - C - C - C - C - C - C - C - C - C - H

H H H H H H H H H H H H

H H H H H H H H H H H H

C 6 H14

H - C - C - C - C - C - C -- H

H H H H H H

H H H H H H

C12H26

Hexane

C 6 H12

C - C - C - C - C - C -- H

H H H H H H

H H H H H

1-Hexene

+

Figure 13–11 Cracking

A typical fluid catalytic cracking unit includes a catalyst regenerator, reactor, and fractionatingtower. During operation, gas oil enters the reactor and is mixed with a superheated powdered cat-alyst.The term cracking or catcracking is applied to the process because during vaporization themolecules literally split; they are then sent to a fractionation tower for further processing. Thechemical reaction between the catalyst and light gas oil produces a solid carbon deposit (coke)that collects on the powdered catalyst and eventually deactivates it. The spent catalyst is drawnoff and sent to the regenerator where the coke is burned off. Catalyst regeneration is a continuousprocess during operation.

In the fractional distillation tower, the light gas oil is separated into five different “cuts”: cat-cracked gas, catcracked naphtha, catcracked heating oil, light gas oil, and residue.

HydrocrackingHydrocracking is a process that industrial manufacturers use to boost gasoline yields. During thisprocess, heavy gas oil molecules are split into smaller, lighter molecules called hydrocrackate.Heavy gas oil feed is mixed with hydrogen before being sent to a first-stage reactor, which is filledwith a fixed bed of catalyst. As process flow moves from the top of the reactor to the bottom, thecracking reaction takes place. First-stage hydrocrackate is sent to a separator drum where thehydrogen is reclaimed; the hydrocrackate is then moved on to a fractionating tower.

In the fractionation tower, the hydrocrackate is separated into five different cuts: butane, lighthydrocrackate, heavy hydrocrackate, heating oil, and heavy bottom. The heavy bottom is mixedwith hydrogen and sent to a second-stage reactor for further processing. The second-stagereactor reclaims as much of the hydrocrackate as possible before sending it to the separatorand tower.

AlkylationAlkylation uses a reactor to make one large molecule out of two small molecules. Alkylation unitstake two small molecules of isobutane and olefin (propylene, butylenes, or pentylenes) and com-bine them into one large molecule of high-octane liquid called alkylate. (Alkylate is a superiorantiknock product that is used in blending unleaded gasoline.) This combining process takes placeinside a reactor filled with an acid catalyst.

After the reaction, a number of products are formed that require further processing to separateand clean the desired chemical streams. A separator and an alkaline substance are used to re-move (strip) the acid.The stripped acid is sent back to the reactor while the remaining reactor prod-ucts are sent to a distillation tower. Alkylate, isobutane, and propane gas are fractionally separatedin the tower. Isobutane is returned to the alkylation reactor for further processing. Alkylate is senton to the gasoline blending unit.

Summary

Chemistry is the study of the characteristics or structure of elements and the changes that takeplace when they combine to form other substances. Process operators play a major role in con-verting raw materials into finished products. Modern chemistry is an essential part of the processenvironment and thus is a vital part of technician training.

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The four physical states of matter are solid, liquid, gas, and plasma.

The purest form of matter is an element, which is composed of identical components called atoms.Elements cannot be broken down or changed by chemical or physical means. The periodic table(chemical element chart) lists information about all known elements, including atomic mass, sym-bol, atomic number, and boiling point.

An atom is the smallest particle of an element that still retains the characteristics of that ele-ment. Atoms are composed of positively charged particles called protons, an equal number ofneutral particles called neutrons, and negatively charged particles called electrons. Protons andneutrons make up the majority of the mass in an atom and reside in an area referred to as thenucleus.The sum of the masses in the nucleus (protons and neutrons) is called the atomic massunit (AMU). The atomic number of an element is determined by the number of protons in itsnucleus.

Orbiting the nucleus are negatively charged electrons. Electrons and protons are equally balancedin an atom, so each atom is electrically neutral. The electrons that reside in the outermost shell ofan atom are called valence electrons; they act as the links in virtually every chemical reaction.Atoms share their valence electrons to form chemical bonds.

The two most common chemical bonds are covalent and ionic. Covalent bonds occur when ele-ments react with each other by sharing electrons, and ionic bonds occur when positively chargedelements react with negatively charged elements to form ionic bonds through the sharing or lend-ing of electrons.

Compounds are the products of chemical reactions. A compound is a substance formed by thechemical combination of two or more substances in definite proportions by weight. A molecule isthe smallest particle that retains the properties of the compound.

Solutions are a type of homogenous mixture. The term homogenous indicates that the solutioncomponents are evenly distributed throughout the mixture. Mixtures do not have a definite com-position. A mixture is composed of two or more substances that are only physically mixed, notchemically combined. Thus, the components of a mixture can be separated through physicalmeans, such as boiling or magnetic processes.

Elements are identified by letters of the alphabet. A periodic table lists the symbols for all knownelements. A chemical reaction can be described by using associated numbers and symbols.

In a chemical equation, the raw materials or reactants are placed on the left side, a yield sign orarrow immediately follows the reactants, and the products are placed on the right side. Becauseatoms cannot be created or destroyed, a common rule of thumb is that the sum of the reactantsmust equal the sum of the products.

Exothermic reactions are accompanied by the liberation of heat. Endothermic reactions must ab-sorb energy to proceed. Replacement reactions can be used to remove undesired products andreplace them with desired ones. Neutralization reactions remove hydrogen ions (acid) or hydroxylions (base) from a liquid to reduce or eliminate the acidity or alkalinity of a solution. Hydrogen ions(acid) and hydroxyl ions (base) neutralize each other.

Summary

301

Combustion reactions are exothermic reactions that require fuel, oxygen, and heat to occur. A firedfurnace or a boiler uses a combustion reaction.

For a chemical reaction to occur, the atoms of the reactants must collide with each other. Theaddition of heat to a process will increase reactant molecular activity, which ensures a much higherrate of energy transfer between molecules as they collide with each other. Reaction rates doublewith every 10 degrees of heat and are affected by heat, surface area, concentration, pressure, flowrates, and the presence of catalysts.

Material balancing is a method technicians use to determine the exact amount of reactantsneeded to produce the specified products. Percent-by-weight solutions are expressed as apercentage of the weight of the solute in relationship to the weight of the entire solution. The termpH refers to the acidity or alkalinity of a solution.

A hydrocarbon is a chemical compound that contains hydrocarbon and carbon. Crude oil is a mix-ture of hydrocarbons that vary in size and structure from simple to complex. Much modern manu-facturing is based on separating the various components in crude oil by their individual boilingpoints. Important applied concepts of chemical processing include distillation, catalytic cracking,hydrocracking, and alkylation.

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303

Chapter 13 Review Questions1. What is chemistry? Why is it important to a process technician?

2. What is matter? List the four states of matter.

3. Describe an atom. What is a proton, electron, valence electron, neutron, AMU, and atomicnumber?

4. What is an element?

5. What is the function of the periodic table? Describe element symbols.

6. Define the terms ion and atom.

7. Define the terms covalent bond and ionic bond.

8. Describe the differences between mixtures and compounds.

9. What is a chemical equation? Describe reactants and products in an equation. What doesthe yield sign mean?

10. H2 � O H2O. Is this chemical equation balanced? List the reactant elements andthe product elements.

11. 8NH3 � 6O2 4N2 � 12H2O. Is this chemical equation balanced? List the reactantelements and the product elements.

12. Determine whether this chemical equation is balanced: H3PO4 � 3NaOH Na3PO4 �3H2O. List the reactant elements and AMUs. List the product elements and AMUs.

13. You are given the chemical equation H3PO4 � 3NaOH Na3PO4 � 3H2O. If you aretold to add 15 lb of phosphoric acid (H3PO4) to this equation, how many pounds will youneed to add to the sodium hydroxide (NaOH) to keep the equation balanced?

14. What is an exothermic reaction? How do you control it?

15. List and describe the different types of chemical reactions.

16. How do heat and pressure affect a chemical reaction?

17. What affects reaction rates?

18. List the different types of catalysts.

19. A 500-lb barrel contains a 10% catalyst solution. What is the weight of the catalyst?

20. Contrast an acid and a base.

21. Describe crude oil distillation.

Applied Physics TwoAfter studying this chapter, the student will be able to:

• Describe the fundamental concepts of physics.• Define key terms used in process physics.• Contrast and compare density and specific gravity.• Describe the principle of pressure in fluids.• Convert inches of water to pounds per square inch gauge.• Convert inches of mercury (Hg) to inches of water.• Describe the relationship between temperature and pressure.• Describe the scientific principles underlying simple and complex machines.• Describe the basic principles of electricity.• Use gas-law formulas to solve simple problems.• Solve simple fluid flow problems.

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Chapter 14 ● Applied Physics Two

Key TermsAPI gravity—standard by which to measure the heaviness or density of a hydrocarbon; aspecially designed hydrometer marked in units API is used.

Atmospheric pressure—the combined weight of all the gases exerted on the surface of theearth. At sea level, the total mass is estimated at 5.5 � 1015 tons, or 760 mmHg, or 14.7 psi,or one atmosphere.

Barometer—an instrument to measure atmospheric pressure; invented by EvangelistaTorricelli in 1643.

Baumé gravity—the standard used by industrial manufacturers to measure nonhydrocarbonheaviness.

Density—the heaviness of a substance.

Energy—anything that causes matter to change and does not have the properties of matter.

Inertia—a principle that explains a body’s ability to resist motion.

Kinetic energy—the energy of motion or velocity.

Mass—the quantity of matter in an object.

Matter—anything that occupies space and has mass or volume.

Potential energy—stored energy.

Specific gravity—a measurement of the heaviness of a fluid. Specific gravity equals the massof a substance divided by the mass of an equal volume of water. The specific gravity of gaso-line is 6.15 lb/gal � 8.33 � 0.738.

Weight—the force of molecular gravitation.

14.1 Fundamental Concepts

Matter and EnergyPhysics is the study of matter and energy. Matter is anything that occupies space and has massor volume. Energy is anything that causes matter to change and does not have the properties ofmatter. Energy takes the form of heat (Btu; causes matter to expand), electricity (kilowatt hour),potential (height, foot-pound), kinetic (moving, foot-pound), light (produces chemical changes infilm), magnetism (creates motion in certain materials), and mechanical work (horsepower hour).

There are two basic states of matter: potential and kinetic. Potential energy is stored energy.Kinetic energy is the energy of motion or velocity.

Specific Properties of MatterOne of the key principles associated with matter is that of attraction or gravitation. All moleculesare attracted to each other. The force of molecular gravitation is called weight. Weight is closelyrelated to mass. If the weight of two bodies is the same, the mass of these bodies is the same.

Gravitational force between two objects is dependent upon the weight of the bodies and the dis-tance between them:The larger the body, the greater the attraction. Force is inversely proportionalto the square of the distance. When the distance between two attracted objects is doubled, theforce is only one-fourth as great.

The mass of an object is identified as the quantity of matter. The measure of a body’s mass is often identified by its weight.

Inertia is a principle used to explain a body’s ability to resist motion. A force must be exerted to movea body that is at rest.To change the speed or direction of a moving object, a force must be applied. Allmatter has inertia.The total amount of inertia a body contains depends on the total mass in the body.

Volume is the space occupied by a body. See Figures 14–1, 14–2, and 14–3 for volume formulasfor a sphere, cylinder, and rectangular solid.

A fundamental principle of matter is that it cannot be created or destroyed, only changed from onestate to another.This principle of indestructibility holds true for energy as well. It can only be trans-formed from one form to another.

Porosity or particle structure is a principle of matter that deals with the vast amounts of space thatexist between molecules. This principle helps explain why mixtures of gases, liquids, or solids canoccupy a smaller volume than the original components.

14.1 Fundamental Concepts

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Radius

Volume = πr3 4 3

Figure 14–1 Volume Formula: Sphere

Radius Height

Volume = πr2h

Figure 14–2 Volume Formula: Cylinder

Volume = lwh

Height

Width

Length

Figure 14–3 Volume Formula: RectangularSolid

Archimedes’ PrincipleArchimedes’ principle applies to specific weight of solids denser than water. The principlestates that:

• A submerged object will displace its own volume of water. (See Figure 14–4.)• Weight loss of the object equals the weight of the water displaced.

EXAMPLE:A chunk of metal weighs 1,000 g in air and 650 g in water. What is its specific weight?

Solution:

Specific weight metal � Weight of metal in air �

1,000 � 2.85

Loss of weight in water (1,000 – 650)

14.2 Density and Specific Gravity

Because the density of liquids and solids varies so much, it is convenient to have a standard tocompare them to.The standard used to compare densities is water.Water weighs 62.5 lb per cubicfoot or one gram per cubic centimeter. The terms specific gravity and specific weight are used tocompare the density of water to another substance. Hydrocarbons are typically lighter than water.Their specific gravities will be less than one, whereas substances heavier than water have specificgravities of greater than one.

Specific gravity is defined as the comparison of a fluid (liquid or gas) to the density of water orair. It is a common mistake for operators to confuse specific gravity with density. This confusion isunderstandable, because specific gravity is a method for determining the heaviness of a fluid.Density is the heaviness of a substance, whereas specific gravity compares this heaviness to astandard and then calculates a new ratio. Most hydrocarbons have specific gravities below 1.0.

Key points to remember:• The specific gravity of water is 8.33 lb/gal � 8.33 � 1.0• The specific gravity of gasoline is 6.15 lb/gal � 8.33 � 0.738

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800 mL

500 mL

Figure 14–4 Displacement

• The density of water is 8.33 lb/gal• The density of air is 0.08 lb per cubic foot• Density is calculated by weighing unit volumes of a fluid at 60 degrees Fahrenheit

(15.5 degrees Celsius).

Determining Specific GravitySpecific gravity is determined by comparing the weight of a volume of material with the weight ofthe same volume of water. There are two methods for determining specific gravity:

Specific gravity �Weight of definite volume of given material

Weight of the same volume of water

Specific gravity of a sinking solid �Weight of the object in airLoss of weight in water

DensityIndustry uses four different ways to express the heaviness of a fluid:

• Density—(Density � Weight � Volume). The density of water is 8.33 lb/gal. Thedensity of a fluid is defined as the mass of a substance per unit volume. Densitymeasurements are used to determine heaviness. D � 8.33 lb � 1 gal. This equationcan also be expressed as W � D � V or as V � W � D.

• Specific gravity—The specific gravity of water is 8.33 � 8.33 � 1. The specific gravityof gasoline is 6.15 lb/gal � 8.33 � 0.738.

• Baumé gravity—This is the standard used by industrial manufacturers to measurenonhydrocarbon heaviness.

• API gravity—The American Petroleum Institute applies API gravity standards tomeasure the heaviness of a hydrocarbon. A specially designed hydrometer markedin units API is used to determine the heaviness or density of a hydrocarbon. High APIreadings indicate low fluid gravity.

The density of a fluid is defined as the mass of a substance per unit volume. Density measure-ments are used to determine heaviness. For example, one gallon of:

water � 8.33 lbcrude oil � 7.20 lbgasoline � 6.15 lb

ViscosityAnother term commonly used in industry to describe the flow characteristics of a substance isviscosity. Viscosity is defined as a fluid’s resistance to flow.

Weight � Volume � Density

Density of water � 1 g per cubic centimeter� 62.5 lb per cubic foot� 1687.5 lb per cubic yard� 16.41 g per cubic inch


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EXAMPLE 1Find the density of helium gas: 20 liters of the gas weighs 3.4 grams.

Solution:

D � WV

D � 3.5 g � 0.17 gl

20L

EXAMPLE 2Find the volume of a granite object with a density of 2.6 g per cubic centimeter and a weight of1,280 g.

Solution:

V � WD

V � 1.280 g � 1.280 (g � cm3) � 492 cm3

2.6 g/cm3 2.6 g

ElasticityElasticity refers to the tendency of a substance to return to its original shape after a distorting forceis removed. Substances such as iron and steel have a high degree of elasticity, whereas sub-stances such as clay or putty have a very low elasticity rating. Steel can be subjected to a force ofthousands of pounds per square inch and yet return to its original shape when the distorting forceis removed.

The term strain is used to describe the total distortion that occurs after the distorting force isremoved. Robert Hooke’s law states that strain is proportional to stress if the stress remains withinthe elastic limit of the material. The elastic limit of a substance is the maximum force a substancecan withstand without breaking or becoming permanently deformed. A spring device can be usedto demonstrate Hooke’s law. Distorting forces can be classified as compressing, stretching, tearing, twisting, and bending.

HardnessThe hardness of a substance is determined by its ability to scratch or mark another substance.Diamond is the hardest natural substance known; gold is very soft.

TenacityTenacity is the ability of a substance to resist being pulled or torn apart. Tenacity per unit area iscalled tensile strength. Tensile strength is measured in pounds per square inch.

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DuctilityDuctility is a material’s ability to be drawn into fine threads. Copper and aluminum, both of whichcan be made into wire, are good examples of materials with high ductility.

MalleabilityMalleability describes the ability of a substance to be beaten or rolled into thin sheets. For exam-ple, gold is extremely malleable: it can be rolled out to a sheet about 1/300,000 inch thick.

AdhesionDissimilar molecules carry very powerful attractive forces, referred to as adhesion. Examples ofmaterials with great adhesion include concrete and glue.

Surface TensionSurface tension is the result of molecular attraction in a liquid that is stronger along the outerperimeter and weaker toward the middle. The liquid acts like a stretched sheet of rubber. Surfaceforces vary from those found deeper in the liquid, because there are no upward forces.

Capillary ActionWhen a liquid comes in contact with the outside of its container, it experiences two forces: cohe-sive force and adhesion.The adhesive force is the result of the attractive forces between the wallsof the container and the fluid; the cohesive force is related to the internal characteristics of the liq-uid. When the adhesive forces of the system are greater than the cohesive internal forces of theliquid, the liquid tends to cling to the sides of the container.This tendency of a liquid to cling to andclimb up the walls of the container is called wetting.

Mercury is so dense that it has the opposite reaction as most liquids. Wetting does not occur;instead, the adhesive forces dome up the mercury near the wall of the container. The density ofthe liquid and the size of the tube determine how high or low a liquid will move inside a container.

Temperature and Cohesive ForceWhen the temperature inside a process system is increased, the cohesive forces between mole-cules are reduced.

EXAMPLE 1What is the density of a cube of iron, 15 cm on an edge, that weighs 9.6 kg?

Solution:

D � WV

D � 9.6 kg � 2.84 g/cm3

15cm3

9,600 � 3,375 � 2.84 g/cm3

Answer: 2.84 g/cm3


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EXAMPLE 2How many liters of alcohol will weigh 30 kg? (Density of alcohol � 0.8 g/cm3)

Solution: Liters of alcohol � 37,500 grams � 1,000 grams � 37.5 L

V � WD

V � 30 g � 37,5000.8 g/cm3

Answer: 37.5 L

Note: 1 kg � 1,000 g

Practical Exercises1. A beam of cedar wood 20 ft long, 2 ft wide, and 6 in. thick weighs 150 lb. Calculate its density.

Show your work!2. A cylinder 4 cm in diameter and 40 cm long is made of brass (density � 8.5 g/cm3). Calculate

its weight. Show your work!3. What is the weight of a rectangular steel bar 15 ft long, 1 ft wide, and 2 in. thick? (Density of

steel � 461 lb/ft3.) Show your work!

Note: W � D � V

14.3 Pressure in Fluids

At sea level, the atmosphere that surrounds the Earth is composed of 78.1% nitrogen, 20.9% oxygen, 0.9% argon, and 0.03% carbon dioxide, as measured in dry air. The remaining compo-nents, in decreasing proportion, include neon, helium, methane, krypton, hydrogen, oxides of nitrogen, and xenon. It should be noted that humid air contains higher percentages of water vapor, which lowers the percentages of the other gases. The area immediately above the surfaceof the Earth, which sustains life and produces our weather, is called the troposphere. In this thin,six-mile-high band, we find rain, clouds, wind, ice, and snow. The temperature of the atmospheredecreases rapidly as we ascend through the troposphere and into the stratosphere where theozone layer is found. The stratosphere extends from 6 miles to 31 miles above the surface of theEarth. The thin, dry air in the middle of the stratosphere is very cold, averaging �55�C. From31 miles to 50 miles above the Earth, we find the mesosphere.The ionosphere is a region of ionizedgases that exists above the mesosphere. Temperature variations in this band rapidly rise and fall.The ionosphere extends from 50 miles to approximately 93 miles above the surface of the Earth.

Atmospheric pressure is the combined weight of all the gases exerted on the surface of theEarth. At sea level, the total mass is estimated at 5.5 � 1015 tons, or 760 mmHg, or 14.7 psi, orone atmosphere. In 1643, Evangelista Torricelli was able to prove his atmospheric theory using adevice called a barometer. Barometer is a combination of Greek words, baros meaning pressureor weight, and metros, meaning measure.Variations in the density of atmospheric gases form high

312


and low atmospheric pressures. As atmospheric pressure increases, our weather improves; as itdecreases, a cloudy, rainy forecast is issued.

Note: 1 psi � 27.7 inches of water � 2.04 inches of mercury (Hg)

Problem: Convert 8” of Hg to inches of water

8 inches of Hg � 27.7 inches of water � 2.04 inches of Hg � 108.627 inches of water

Inches of water can be converted to psig using the following equation: height of liquid � 27.7.Inches of mercury (Hg) can be converted to psig using the following equation: height of liquid � 2.04.

Force and PressureForce is a push or a pull that is used to change the direction, speed, or shape of a body. Gravita-tional force in liquids and pressure in fluids share a unique relationship. Pressure is the total forcedivided by the area. Force is measured in units of weight:

P (pressure) � F (force) � A (area)

EXAMPLE 1A rectangular tank 10 ft square and 8 ft deep is filled with water. The volume of the tank is 800 ft3.Water weighs 62.5 lb/ft. Calculate the total force exerted by the water against the bottom ofthe tank.

Solution:Total Force � Area � Height � Density

F � A � H � DF � 10 ft2 � 8 ft � 62.5 lb/ft3 � 50,000 lb

Answer: The total force exerted by the water against the bottom of the tank is 50,000 lb.Pressure (P) � Force (weight) � Area

EXAMPLE 2Calculate the pressure produced by a 2,000-lb stone block, 40 in. length � 20 in. width.The heightis not required to solve this problem.

Solution:The area occupied by the stone � 800 in.2

40 in. length � 20 in. wide � 800 in.2

P � 2,000 � 800 � 2.5 psi

Answer: The pressure at the base of the stone � 2.5 psi.


313

EXAMPLE 3Calculate the pressure produced by a 10-ft onion tank filled with a hydrocarbon fluid (0.72 sg).Vapor pressure is 200. Add 45 psi N2 to the total. What is the final pressure?

Solution:Height � 0.433 � Specific Gravity � Pressure10 ft � 0.433 � 0.72 sg � 3.1 psi3.1 psi � 200 � 45 psi � 248.1 psi

Answer: 248.1 psi

Practical Exercises1. Calculate the pressure produced by a 456-lb granite block, 10 in. length � 15 in. width �

72 in. height.2. Calculate the pressure produced by a 40-ft onion tank filled with 17.5 ft of a hydrocarbon fluid

(0.54 sg). Vapor pressure is 300 psi. Add 15 psi N2 to the total. What is the final pressure?3. Calculate the pressure produced by water in a 14.5-ft-high vessel.4. Calculate the pressure exerted on the bottom of a 69-ft distillation column by a 10-ft hydrocar-

bon level. Specific gravity is 0.67. Vapor pressure at 240 degrees Fahrenheit (115.5 degreesCelsius) is 236. One hundred psi is added to the column, giving a top gauge reading of____________ psi and a bottom gauge reading of ____________ psi.

5. What pressure, in pounds per square inch, is a scuba diver subjected to when descending toan ocean depth of 125 ft?

6. A rectangular vessel 10 ft wide, 20 ft long, and 12 ft deep is filled with mercury (specific gravity � 13.5). Answer the following questions using the pressure equation P � F�A:a. What is the pressure on the bottom of the tank?b. Identify the pressure on one side of the vessel at the 6-foot mark.c. What is the total force on the bottom of the tank?d. Identify the pressure at the top of the tank.

Flow Rate CalculationsAnother common problem encountered by process technicians is the calculation of flow rate.Figure 14–5 shows the various components found in a simple pump system: valves, piping, a flowcontrol loop, and a pump. The simple equation used to calculate flow rate is:

FR � Volume � Time

Sample Problem: Calculate the flow rate (FR) of the following pump-around system.

FR �?Volume � 600 gallonsTime � 3 minutesFR � 600 gallons � 3 minutesFR � 200 GPM

Pressure/Temperature RelationshipsIn larger commercial operations, a distillation system has a complex feed and storage system,which includes a series of tanks that are used to provide a steady flow of raw materials to the

314


column, and a system of tanks for new product storage. Process technicians operating these sys-tems should be aware of the science and physics associated with this equipment. Charles’s lawand the ideal gas law illustrate the close relationship between temperature and pressure inside anenclosed vessel. In the system shown in Figure 14–6, a hot liquid (200�F) is allowed to coolovernight in an enclosed vessel to 78�F. We can see the relationship between temperature andpressure using the following formula:

P2 � P1 � T2 � T1

P2 � ?P1 � 24.7 psiaT1 � 200�F � 460 � 660�RT2 � 78�F � 460 � 538�R24.7 psia � 538�R � 13288.6 � 660�R � 20 psiaP2 � 20 psia

Compressors come in a variety of styles and designs; the most common being dynamic and pos-itive displacement. Each of these designs is governed by standard scientific principles that shouldbe well understood by process technicians assigned to these areas. Because compressors are sowidely used, almost every process technician will come into contact with a compressor system.The compression of gases and vapors in the process industry is very important and is used in thefollowing applications:

• air• nitrogen• natural gases and hydrocarbons• hydrogen, carbon dioxide, carbon monoxide, chlorine, helium, argon• other vapors and gases


315

FT

I P

Pi

Centrifugal Pump

Flow Rate = Pi

M

NPSH

NPDH

FIC 200

GPM

Volume Time

600 gallons 3 minutes

FR =

200 gallons FR =

Figure 14–5 Flow Rate Calculation

When a gas is compressed, the molecules that make up the gas are moved closer together.This in-creases the chances of molecular collisions that produce heat and increase the pressure beyond thenormal calculated compression ratio. Figure 14–7 shows a typical compressor system, illustratingthe various components and process variables associated with the system as it is started up. Thescientific comparison is between the initial conditions or process variables and the operating vari-ables. (This figure does not show an inner-cooler or an after-cooler, to illustrate what happens whenthese systems are not used.) The starting pressure is 14.7 psia and final pressure is 35 psia. Usingthe formula:T2 � P2 � T1 � P1, it is possible to observe the operation of the scientific laws that takesplace when the compressor is started up. As the pressure increases, so does the temperature.

Formula: T2 � P2 � T1 � P1

P1 � 14.7 psiaT1 � 70�F � 460 � 530�RT2 � ?P2 � 35 psia

Formula: T2 � P2 � T1 � P1

35 psia � 530�R � 14.7 psia � ?1262�R � 460 � 802�FT2 � 802�F

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FT

IP

Pi

Centrifugal Pump

Pi

M

NPSH

P

NPDH

FIC

Differential Pressure4.7 psi

P = 24.7 psiaT = 200ºF + 460 = 660ºRT = 78ºF + 460 = 538ºR

P = P T T

(24.7 psia) (538ºR)660ºR

P = 20 psia

1

1

T1

T2

P2

1

1

1

2

22

2

ClosedClosed

24.7 psia 20 psia

200ºF 78ºF

Figure 14–6 Enclosed Tank

Heat Exchangers:Temperature vs. PressureA heat exchanger is an energy transfer device, however, a number of scientific principles governwhat happens inside this unusual device. Some of these principles include the laws of heat transfer,thermal expansion, pressure, and fluid flow, among others.The operation of a heat exchanger pres-ents a number of hazardous situations. It is possible, for instance, to create a bomb by closing thewrong valves. In this example, we will look at how isolating an exchanger could create a vacuum thatmay damage or collapse the shell. In Figure 14–8, the shell inlet and outlet are blocked and the hotliquid (350�F) is allowed to cool down to a temperature of 33�F in an enclosed shell.

Formula: P2 � P1 � T2 � T1

P2 � ?P1 � 19.7 psiaT1 � 350�F � 460 � 810�RT2 � 33�F � 460 � 493�R19.7 psia � 493�R � 9712 � 810�R � 12 psiaP2 � 12 psia

The shell will be under a vacuum as the materials cool down to 33�F. Most industrial equipment isdesigned to handle pressure from the inside out, not from the outside in.


317


P

P

T

?

T

PiPi

Pi

Airinlet

Receiver

End: 35 psia

Start: 14.7 psia

M

1

P1

1

T1

35 PSIA

14.7 PSIA70ºF

2

P2

2

T2 =

Figure 14–7 Compressor System

In the next example, the heat exchange moves in the opposite direction. In most heat exchangers,the shell is able to handle higher temperatures and pressures; in Figure 14–9, however, we seehow the tubes can be damaged by a technician who is unfamiliar with the scientific principles as-sociated with operating a heat exchanger.

In the past, many senior technicians simply taught new technicians which valves to open and whichsequence to do it in.Very little discussion was had concerning the science of what was taking placeinside the device. Modern technicians are required to understand the science and technology as-sociated with modern process control. In the following example, the tubes are rated at 50 psia @800�F. If these limits are exceeded, hazardous conditions will be created, under which the tubescould rupture. Because the tubes are hidden in the shell, it is difficult for a new technician to im-mediately recognize that a serious problem has occured.

Formula: P2 � P1 � T2 � T1

P2 � ?P1 � 30 psiaT1 � 350�F � 460 � 810�RT2 � 1000�F � 460 � 1460�R30 psia � 1460�R � 43,800 � 810�R � 54 psiaP2 � 54 psia

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Pi

Pump

Heat Exchanger

Hot Oil Closed

Closed

Closed

T 1

T 2 P 1 P 2 =

P

P

T

?

T

1 1

19.7 PSIA 350ºF

33ºF

2 2

Figure 14–8 Heat Exchanger—Temperature vs. Pressure 1

319

14.4 Complex and Simple Machines

WorkWork is the process of overcoming the downward pull of gravity and moving a body that has beenat rest. When you attempt to lift a body at rest, work is not accomplished unless the object is lifted.Work is equal to force times distance.

W � FD

EXAMPLECalculate how much work is done when a force of 50 lb is applied to push a wagon 20 ft.

Solution:To solve this problem, multiply the applied force (50 lb) by the distance through which the forceacts (20 ft).


Pi

Pump

Heat Exchanger

Hot Oil Closed

Closed

Closed

T 1

T 2 P 1 P 2 =

P T 1 1

30 PSIA 350ºF

P

?

T

1000ºF

2

P 2

2

=

P 2 =

(30 psia) (1460ºR)

810ºR

54 psia

Figure 14–9 Heat Exchanger—Temperature vs. Pressure 2

Work � Force � DistanceW � F � D

� 50 lb � 20 ft � 1,000 ft-lb

Answer: 1,000 ft-lb.

Practical Exercises1. Calculate the amount of work accomplished by a 3-ft table holding up a 2-lb book.2. Calculate the amount of work accomplished when a weight is lifted 240 ft by a force of 600 lb.

(Work � Force � Distance)3. A man weighing 190 lb climbs a 35-ft staircase in 25 sec. Calculate how much work was

performed.

Mechanical AdvantageMechanical advantage (MA) is the ratio between resistance overcome and effort applied. Whendetermining the mechanical advantage of a system, the resistance is divided by the effort. For ex-ample, when a 100-lb force moves a resistance force of 400 lb, the machine has a mechanicaladvantage of 4. Actual MA is calculated using the following equation:

MA � Resistance � R Effort E

Inclined PlaneWhen an object is rolled or slid up a ramp, the scientific principle of the inclined plane comes intoplay. Inclined planes are very useful when one must move large, heavy objects from one level toanother. Other examples of application of this principle include stairways, ramps, inclined roads,and inclined tracks.

In the inclined plane principle, ideal MA is calculated by using the resistance force (gravity) thatovercomes the vertical height of the plane and the effort force (length) that acts through the entirelength of the plane. For example:

Ideal MA � De � Length of plane Dr Height of plane

EXAMPLEA 24-ft-long inclined ramp extends from the ground to a height of 8 ft. A force of 180 lb is requiredto roll a 420-lb cart up the ramp.

• Calculate the actual MA.• Calculate the ideal MA.• Calculate the efficiency.• Calculate how much work is accomplished against gravity.• Calculate how much work is done in overcoming friction.

Solutions:

Actual MA � R � 420 lb � 2.33E 180 lb

320


321

Ideal MA � De � 24 ft � 3.0Dr 8 ft

Efficiency � Actual MA � 2.33 � 77%Ideal MA 3

Work output � R � Dr � 420 lb � 8 ft � 3,360 ft-lbWork to overcome traction � Work input � Work output

� (E � De) � (R � Dr)� (180 lb � 24 ft) � (420 lb � 8 ft)� 960 ft-lb

The Principle of Moments and Levers The principle of moments and levers can be illustrated us-ing an ordinary playground seesaw. A seesaw is designed to operate like a balanced lever. Twoarms of equal length extend across the fulcrum. When a force acts upon the lever arm, it causesa reaction. The lever will remain balanced only if the two forces acting on the seesaw are distrib-uted equally. The point along the lever where the force is applied is important to this distributionconcept.

The moment of a force is equal to the product of the force and the perpendicular distance from thefulcrum.

EXAMPLE 1Do the total clockwise moments balance the total counterclockwise moments in Figure 14–10?

Solution:Counterclockwise ClockwiseForce � Distance � Moment Force � Distance � Moment50 lb � 6 ft � 300 ft-lb 60 lb � 5 ft � 300 ft-lb12 lb � 4 ft � 48 ft-lb 4 lb � 12 ft � 48 ft-lb CCW Moments � 348 ft-lb CW Moments � 348 ft-lb

If the force and distance are perpendicular to each other, no work is accomplished. When a leveris in equilibrium, the total counterclockwise and clockwise forces are equal.

50 lb

6 ft-0 in.

12 lb

60 lb

4 lb

5 ft-0 in.

12 ft-0 in.

4 ft-0 in.

Figure 14–10 Law of Moments 1


EXAMPLE 2A balanced lever arm rests on a fulcrum at its center. A 200-lb force is applied 5 ft from the ful-crum. To maintain equilibrium, how far from the fulcrum, on the other lever arm, should a 100-lbforce be applied?

Solution:CCW moments � CW moments200 lb � 5 ft � 100 lb � x ft

x � 10 ftAnswer: 10 ft

EXAMPLE 3A 200-lb weight and a 100-lb weight rest 8 ft and 6 ft from the fulcrum. A 200-lb weight rests onthe opposite side. How many feet from the fulcrum must the weight be placed to establish equilib-rium?

Solution:(200 lb � 8 ft) � (100 lb � 6 ft) � 200 lb � x ft

x � 1,600 � 600 � 11 ft200

Answer: 11 ft

EXAMPLE 4A balanced lever arm rests on a fulcrum at its center. A 600-lb force is applied 5 ft from the fulcrum(Figure 14–11). To maintain equilibrium, how far from the fulcrum, on the other lever arm, shoulda 1200-lb force be applied?

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1200 lbs.

600 lbs.

5 ‘ ? ‘

Figure 14–11 Law of Moments 2

Solution:CCW moments � CW moments

600 lb � 5 ft � 1200 lb � x ft3000 � 1200 � 2.5

x � 2.5 ft

Answer: 2.5 ft

14.5 Electricity

Electricity is a primary part of modern industrial operation. It is used to operate motors that providethe rotational energy for pumps, compressors, fans, mixers, conveyors, generators, extruders, andmany other critical pieces of equipment. It is also used for lighting, air conditioning, electrical out-lets, and modern process control.Without electricity the world would be a very different place, voidof many of the comforts we take for granted. To operate a plant efficiently, a process technicianneeds to have a basic understanding of electricity and the equipment it operates.

Electric current is defined as electrons in motion. Electricity is often defined as the movement ofelectrons from one point to another. Nearly all of the electrical energy in the world is delivered byalternating current (AC); this form of electricity cannot be produced by batteries, but must be gen-erated by strong magnetic fields. Alternating current is a flow of electrons that reverses direction atregular intervals. The term alternating current cycle really means a circle. An AC generator is a ro-tating machine that converts mechanical energy into electrical energy or alternating current.

Another form of electrical energy is direct current, defined as the flow of electrons in one direction.A battery can generate direct current (DC). An example of this is a battery connected to a lightconnected to a switch connected to a battery. Figure 14–12 illustrates the key components of a DCcircuit.

Electricity is produced by a series of processes that should be very familiar to most process tech-nicians. A steam-generation system or boiler provides useful steam to drive a steam turbine thatis connected to an electric generator. The electric generator sends (11,000V) current to a step-uptransformer that delivers this load to high-voltage power lines.These step-up transformers step thevoltage up 25 times to 275,000 volts. The ability to use the transformer for step-up or step-downpurposes is the primary advantage of alternating current over direct current.These power lines areused to distribute electricity across a wide network. The high-voltage power lines (275,000V) areconnected to a step-down transformer. This type of transformer is designed to reduce the currentto useable voltages like 110V and 220V.

Ohm’s LawThe relationship between current, resistance, and electric potential was first discovered and describedby a German scientist named George S. Ohm (1784–1854). Ohm’s law describes how the amount ofcurrent that flows through a wire depends on the resistance it must overcome and the electrical pressure or voltage that is pushing the electrons.The greater the voltage, the greater the current; con-versely, the greater the resistance, the less the current.

Resistance: The Ohm. Different substances have different resistances to the flow of electricity. Met-als are typically good conductors of electrons; silver and copper are two of the best conductors.

14.5 Electricity

323

Glass, rubber, and sulfur offer very high resistance and therefore are good insulators. Resistanceis affected by the length of the substance in the direction of current flow: The longer the distance,the greater the resistance. Resistance is also affected by the temperature of the substance. In elec-trical formulas, the capital letter R stands for resistance, and the capital Greek letter omega (�) isthe symbol for ohm. For example, resistance equals 50 ohms is expressed as R � 50 �.

The Ampere. The unit for electric current is the ampere (A). One ampere is equal to a flow of1 coulomb per second. In applications or equations where the ampere is too large, milliampere(mA) is used. A milliamp is a thousandth (0.001) of an amp. In an electrical formula, the capitalletter I represents current. Thirty amperes would be represented as I � 30A.

Electric Potential: The Volt. An electric generator or battery provides a constant source of elec-tric potential. The unit of electric potential (E) is the volt (V). For example, the electric potential ofa 12-volt battery could be written as E � 12V. One volt will cause one ampere of current to flowthrough a resistance of one ohm.

V � voltage (also expressed as E � electric potential in V)I � current in A

R � resistance in �

Depending on the value needed, Ohm’s law can be expressed algebraically in three ways:

1. V � IR (used to find the voltage when current and resistance are specified)2. I � V�R (used to find current when voltage and resistance are known)3. R � V�I (used to find resistance when voltage and current are specified)

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+ _

Light

Switch

Battery

Figure 14–12 Direct-Current Circuit

EXAMPLE 1What current, in amps, will flow through a conductor with a resistance of 20 ohms if the potentialdifference is 240 volts?

Solution:

I � V � R� 240 volts � 20 ohms� 12 amps

EXAMPLE 2An electric device uses 8 amps of current on a 120-volt circuit. What is the resistance?

Solution:

I � V � RR � V � I

� 120 volts � 8 amps� 15 ohms

EXAMPLE 3An electric motor on a centrifugal pump has a total resistance of 6 ohms. If the motor uses 19 ampsof current, what voltage does the motor need?

Solution:

I � V � RV � IR

� 19 amps � 6 ohms� 114 volts

Steam Turbine and Heat Rate EquationA steam turbine is a device used to create useful rotational energy for the purpose of operatingany number of rotational devices.These devices include pumps; compressors; electric generators;turbo-electric locomotives; rotating shafts on submarines, ships, automobiles; fans; and a wide as-sortment of other devices used in industry and our society. In a steam turbine, high-pressure steamis directed against a set of rotating and fixed blades. The design of the blading creates a very pro-ductive pumping action as the steam moves from rotating to fixed to rotating blading. Modernsteam turbine design may have as many as 50 or more stages linked along a horizontal shaft. Eachshaft consists of a set of moving and stationary blades. The curved blades of each stage are de-signed so that the spaces between the blades act as nozzles that increase steam velocity.The ro-tating blades are precision-mounted to a rotating shaft, making it appear to be one seamless unit.The fixed blades are half-crescent devices mounted to the lower casing. Because steam expandsas it enters the turbine, the blades gradually increase in diameter within the body of the device,creating a conical shape. In modern steam turbines, the steam used to operate the device entersat temperatures as high as 538�C and pressures as high as 3,500 psi at the nozzle block and200 psi at the exhaust port.

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The basic components of a steam turbine are:• rotor• fixed blades and moving blades• steam chest• strainer• governor valve• overspeed trip• nozzle blocks• governor system• steam inlet and outlet• casing• seals and bearings

Process technicians perform simple calculations associated with the operation of a steam turbinesystem. Figure 14–13 shows the typical variables on a steam turbine. Heat rate � steam flow �specific heat capacity � temperature difference. The heat-rate formula is:

Rh � Ws � c � T

Rh � heat rate in btu/hrWs � steam flow in lb/hr

c � specific heat capacity in btu/lb �FT � change in temperature in �F

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Pi

Centrifugal Pump

Specific Heat Capacity for Steam c = 0.48

Steam Turbine

Ti 412ºF

Steam: 600 ibs per hr.

212ºF Ti

Pi

NPSH

NPDH

Figure 14–13 Steam Turbine

EXAMPLE 1Determine the heat rate.Steam enters a turbine at 412�F at atmospheric pressure. Steam at 600 lb flows through the turbine each hour during normal operation.

Rh � ?Ws � 600 lbs/hr

c � 0.48Tin � 412�F

Tout � 212�FT � 412�F � 212�F � 200�F

Formula: Rh � Ws � c � T

600 � 0.48 � 200�F � 57,600 btu/hr

Note: 57,600 btu/hr is the amount of heat turned into useful work each hour.

EXAMPLE 2Calculate the horsepower (HP) output.

Formula: HP � heat rate � 0.000393

HP � ?Rh � 57,600 btu/hrHP � 57,600 btu/hr � 0.000393

� 22.6 HP

EXAMPLE 3Identify the steam turbine’s thermal efficiency.

Formula: e � (Tin � Tout) � Tin

First, convert �F to �C to K

�C � (�F � 32) � 1.8412�F � 211�C � 273 � 484K212�F � 100�C � 273 � 373K

e � (Tin � Tout) � Tin � 100 �e � 484K �373K � 111K � 484K �.23 � 100 � 23%

� 23% thermal efficiency

Note: This information is very useful in identifying correct pipe sizes and equipment sizes.

Heat Exchanger and Thermal EfficiencyA heat exchanger is an energy transfer device that is designed to transfer heat energy between sep-arate streams without physically mixing the streams. Heat transfer takes place primarily throughconduction and convection. A heat exchanger has a series of tubes that are surrounded by a shelland attached to an inlet head and in some models an out head. A typical heat exchanger has a shell

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327

inlet and outlet, a tube inlet and outlet, a shell, and tubes.These heat transfer devices are very com-mon and are used in numerous applications. In the following example, steam enters the upper shellinlet at 400�F and exits at 180�F. During normal operation, approximately 600 lb of steam flowsthrough the shell per hour. An impingement baffle is located on the shell inlet to deflect and reduceany damage to the tubes. In solving the following problem, refer to Figure 14–14.

EXAMPLE 1Determine the thermal efficiency of the heat exchanger.

Formula: e � (Tin � Tout) � Tin

First, convert �F to �C to K.

(400�F � 32) � 1.8 � 204�C � 273 � 477K(180�F � 32) � 1.8 � 82�C � 273 � 355Ke � (477K � 355K) � 477K � 100 � 26%

Summary

Physics is the study of matter and energy. Matter is anything that occupies space and has massor volume.The specific properties of matter are weight, mass, inertia, volume, indestructibility, andporosity.

Energy is anything that causes matter to change and does not have the properties of matter.Forms of energy include heat, electricity, potential, kinetic, light, magnetic, and mechanical. There

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Heat Exchanger

Steam In

e =

Ti

180ºF

Ti

400ºF

T in

T in

T in - T out

T out

Figure 14–14 Heat Exchanger and Thermal Efficiency

are two basic states of energy: potential and kinetic. Potential energy is stored energy, and kineticenergy is the energy of motion or velocity.

Because the density of liquids and solids varies so much, we use a standard to which to comparethem.The standard used to compare densities is water.Water weighs 62.5 lb per cubic foot or onegram per cubic centimeter.

Specific gravity is the comparison of a fluid (liquid or gas) to the density of water or air; it is amethod for determining the heaviness of a fluid. Density is the heaviness of a substance. Most hy-drocarbons have specific gravities below 1.0 (that is, they are typically lighter than water). Specificgravity is determined by comparing the weight of a volume of material with the weight of the samevolume of water.

Industry uses four different ways to express a fluid’s heaviness: density, specific gravity, Baumégravity, and API gravity. The density of a fluid is the mass of a substance per unit volume.

The term used by industry to describe a fluid’s resistance to flow is viscosity.

Elasticity refers to the tendency of a substance to return to its original shape after a distorting forceis removed. Strain is the total distortion that occurs after the distorting force is removed. RobertHooke’s law states that strain is proportional to stress if the stress remains within the elastic limitof the material. Distorting forces take the form of compressing, stretching, tearing, twisting, andbending. The elastic limit of a substance is the maximum force that substance can withstand with-out breaking or becoming permanently deformed.

The hardness of a substance is determined by its ability to scratch or mark another substance.Tenacity is the ability of a substance to resist being pulled or torn apart. Tenacity per unit area iscalled tensile strength and is measured in pounds per square inch. Ductility is a material’s abilityto be drawn into fine threads. Malleability refers to the ability of a substance to be beaten or rolledinto thin sheets.

Dissimilar molecules carry very powerful attractive forces referred to as adhesion. Surface tensionis the result of molecular attraction in fluids, which is stronger along the outer perimeter andweaker toward the middle. Surface forces vary from those found deeper in the liquid because thereare no upward forces.

When a liquid comes in contact with the outside of its container, it experiences both cohesive forceand adhesion. The adhesive force is the result of the attractive forces between the walls of the con-tainer and the fluid, and cohesive force is related to the internal characteristics of the liquid.The den-sity of the liquid and the size of the tube determine how high or low a liquid will move inside a container.

When the temperature inside a process system is increased, the cohesive forces between mole-cules are reduced. Force is defined as a push or a pull that is used to change the direction, speed,or shape of a body. Gravitational force in liquids and pressure in fluids share a unique relationship.Pressure is the total force divided by the area. Force is measured in units of weight.

Work is the process of overcoming the downward pull of gravity and moving a body that has beenat rest. It is equal to force times distance (W � FD).

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Summary

Mechanical advantage is the ratio between resistance overcome and effort applied. When deter-mining the mechanical advantage of a system, the resistance is divided by the effort.

The moment of a force is equal to the product of the force and the perpendicular distance from thefulcrum. If the force and distance are perpendicular to each other, no work is accomplished.

Ohm’s law states that the amount of current that flows through a wire depends on the resistanceit must overcome and the electrical pressure or voltage that is pushing the electrons. The greaterthe voltage, the greater the current; conversely, the greater the resistance, the less the current.Ohm’s law is used to describe the relationship between current, voltage and resistance.


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Chapter 14 Review Questions1. What is the volume of a rectangular object 4 ft long, 3 ft wide, and 10 ft high?

2. What is the volume of a cylinder that has a 15-ft diameter and stands 22 ft tall?

3. Find the density of hydrogen gas: Forty liters of the gas weighs 3.3 g.

4. Find the volume of a metal object with a density of 4.6 g per cubic centimeter and a weightof 4,280 grams.

5. What is the density of a cube of iron, 25 cm on an edge, that weighs 16.5 kg?

6. How many liters of alcohol will weigh 80 kg? (Density of alcohol � 0.8 g/cm3)

7. A beam of cedar wood 43 ft long, 3 ft wide, and 6 in. thick weighs 350 lb. Calculate itsdensity.

8. A cylinder 6 cm in diameter and 30 cm long is made of brass (density � 8.5 g/cm3).Calculate its weight.

9. What is the weight of a rectangular steel bar 10 ft long, 2 ft wide, and 2 in. thick? (Densityof steel � 461 lb/ft3.)

10. Calculate the pressure produced by a 3,500-lb stone block, 60 in. length � 20 in. width �72 in. height.

11. Calculate the pressure produced by a 956-lb granite block, 110 in. length � 15 in. width �72 in. height.

12. Calculate the pressure produced by a 22-ft onion tank filled with a hydrocarbon fluid(0.72 sg). Vapor pressure is 430. Add 55 psi N2 to the total. What is the final pressure?

13. Calculate the pressure produced by water in a 19.5-ft-high vessel.

14. Contrast density and specific gravity.

15. Calculate the pressure exerted on the bottom of a 79-ft distillation column by a 10-fthydrocarbon level. Specific gravity is 0.67. Vapor pressure at 240 degrees Fahrenheit(115.5 degrees Celsius) is 236. One hundred psi is added to the column, giving a top gaugereading of ______________ psi and a bottom gauge reading of ______________ psi.

16. What pressure, in pounds per square inch, is a scuba diver subjected to when descendingto an ocean depth of 105 ft?

17. A chunk of rock weighs 1,000 g in air and 350 g in water. What is its specific weight?

18. Calculate how much work is done when a force of 50 lb is applied to push a wagon 20 ft.To solve this problem, multiply the applied force (50 lb) by the distance through whichthe force acts (20 ft).

19. Calculate the amount of work accomplished by a 2-ft table holding up a 2-lb book.

20. Calculate the amount of work accomplished when a weight is lifted 140 ft by a force of300 lb.

21. A man weighing 150 lb climbs a 35-ft staircase in 15 seconds. Calculate how much workwas performed.

22. A 20-ft-long inclined ramp extends from the ground to a height of 6 ft. A force of 190 lbis required to roll a 520-lb cart up the ramp.a. Calculate the actual MA.b. Calculate the ideal MA.c. Calculate the efficiency.d. Calculate how much work is accomplished against gravity.e. Calculate how much work is done in overcoming friction.

23. A 1,600-lb weight and a 400-lb weight rest 8 ft and 6 ft from the fulcrum. A 700-lb weightrests on the opposite side. How many feet from the fulcrum must the weight be placed toestablish equilibrium?

24. What current, in amps, will flow through a conductor with a resistance of 20 ohms if thepotential difference is 120 volts? (I � V � R)

25. An electric motor on a centrifugal pump has a total resistance of 6 ohms. If the motor uses21 amps of current, what voltage does the motor need? (V � IR)

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Environmental StandardsAfter studying this chapter, the student will be able to:

• Define the key terms associated with environmental awareness training.• Describe air pollution control.• Discuss water pollution control.• Explain solid waste control.• Describe toxic substances control.• Explain emergency response.• Discuss the community right-to-know principle.

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Chapter 15 ● Environmental Standards

Key TermsAir permits—government-granted licenses that must be obtained for any project that has thepossibility of producing air pollutants.

Air pollution—contamination of the air, especially by industrial waste gases, fuel exhausts,or smoke.

Community Awareness and Emergency Response (CAER)—a program designed to informthe community surrounding a plant of potentially hazardous situations and of hazardous chem-icals found in the plant, to work with the community to develop emergency response programs,and to open the lines of communication between industry and the community.

Clean Air Act—legislation intended to enhance the quality of the nation’s air, accelerate anational research and development program to prevent air pollution, provide technical andfinancial assistance to state and local governments, and develop a regional air pollution con-trol program.

Clean Water Act of 1972—legislation adopting the best available technology (BAT) strategyfor all cleanups.

Community right-to-know—a principle holding that a community should be aware of thechemicals manufactured or used by local chemical plants and business. Legislation, regulations,and programs based on this principle are intended to involve the community in emergency re-sponse plans, improve communication and understanding between industry and the surround-ing community, improve local emergency response planning, and identify potential hazards.

Emergency response—actions taken when an emergency occurs in an industrial environment;follows a specific set of standards. Drills are carefully planned and include preparations forworst-case scenarios (e.g., vapor releases, chemical spills, explosions, fires, equipment failures,hurricanes, high winds, loss of power, and bomb threats or bombings).

Environmental Protection Agency (EPA)—a federal agency with authority to make andenforce environmental policy.

Resource Conservation and Recovery Act (RCRA)—federal law enacted in 1976 to protecthuman health and the environment. A secondary goal is to conserve natural resources. It attainsthese goals by regulating all aspects of hazardous waste management, including generation, stor-age, treatment, and disposal. This concept is referred to as “cradle to grave” management.

Solid waste—a by-product of modern technology; technically defined as a discarded solid,liquid, or containerized gas. This definition includes materials that have been recycled orabandoned through disposal, burning or incineration, accumulation, storage, or treatment.

Toxic Substances Control Act of 1976 (TSCA)—federal legislation intended to protect humanhealth and the environment, and to regulate commerce by requiring testing and imposingrestrictions on certain chemical substances. The TSCA applies to all manufacturers, exporters,importers, processors, distributors, and disposers of chemical substances in the United States.

Water permit—government-granted license issued as part of efforts to control water pollution.

Water pollution—contamination of the water, especially by industrial wastes.

15.1 Air Pollution Control

Modern technology produces a variety of useful products. This same technology producesby-products that can harm the environment. Because of the potential hazards that accompanytechnology, environmental laws and regulations have been passed to protect our future.The purposeof the Clean Air Act is to enhance the quality of the nation’s air; accelerate a national researchand development (R&D) program to prevent air pollution; provide technical and financial assis-tance to state and local governments for dealing with air pollution; and develop a regional airpollution control program.

Air Pollution ControlIn 1955, the original Clean Air Act was passed to fight air pollution. Over the years, a number ofmodifications have been made to that act:

1960 amendment—directed Surgeon General to study vehicle pollution1963 amendment—directed research into fuel desulfurization and development of airquality criteria1965 amendment—mandate to study new sources of pollution1967—Quality Air Act1970—Clean Air Amendment1977 amendment—the Clean Air Act for emission standards1990—reauthorization of federal Clean Air Act

• Air toxins• Acid deposition• Job training for workers laid off because of Clean Air Act requirements• Air quality standards• Permits• Stratospheric ozone and global climate protection• Provisions for enforcement• Acid rain and air monitoring research• Provision to improve air quality and visibility near national parks• Provisions relating to mobile sources

AgenciesThe Environmental Protection Agency (EPA) was established in 1970. The EPA is an indepen-dent agency of the United States government whose primary purpose is to protect the environmentfrom pollution. The EPA has authority to develop and enforce environmental policy.

The Air Pollution Control Board maintains numerous regional offices throughout each state. Eachlocation receives public complaints, coordinates investigations, documents violations, and recom-mends enforcement actions.

Air PermittingAir permits must be obtained for any project that has the possibility of producing air pollutants.The Air Control Board (ACB) takes about three to eight months to complete the permitting process.After the ACB issues a permit, which will place limits on emissions, a yearly inspection is scheduled.

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Penalties for civil and criminal abuses of the Clean Air Act range from $25,000 a day to $250,000and 2 to 15 years in jail. For example, smoking flares in excess of 5 minutes must be reported. Fail-ure to report results in severe penalties.

15.2 Water Pollution Control

The federal Clean Water Act was passed in 1898 to fight water pollution. Fifty years later, Con-gress provided funds for the construction of municipal wastewater treatment facilities. The WaterControl Act of 1965 took a “water quality” approach and initiated close examination of receivingwaters. States were required to establish standards for water quality.

The Clean Water Act of 1972 adopted the best available technology (BAT) strategy for allcleanups. Under the 1987 amendments to this act, states are required to identify waters that arenot expected to meet quality standards.

Water Pollution Standards and RegulationsThe Clean Water Act regulates wastewater. Wastewater standards are applied to:

• Process wastewater—process contact water; contaminated water from vessels andequipment, tanks, slab cleanup, and so on

• Rainwater—sewer system releases• Once-through cooling water—cooling-tower blowdown or boiler blowdown

The federal Clean Water Act is designed to protect U.S. water quality. The EPA, state watercommissions, the Army Corps of Engineers, state Parks and Wildlife departments, and the U.S.Department of Fisheries and Wildlife help enforce the Clean Water Act.

National Water Quality StandardsNational Water Quality Standards state that:

• All U.S. waters shall be fishable and swimmable.• No discharge of toxic pollutants in toxic quantities will be allowed.• Technology must be developed to eliminate pollutant discharge.

Water PermittingThe Clean Water Act requires a company to have a water permit, similar to an air permit. In somestates, a two-permit system exists.

15.3 Solid Waste Control

Solid waste is a by-product of modern technology. Solid waste is technically defined as a dis-carded solid, liquid, or containerized gas. This definition includes materials that have beenrecycled or abandoned through disposal, burning or incineration, accumulation, storage, ortreatment.

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The Resource Conservation and Recovery Act (RCRA) was enacted as public law in 1976.Thepurpose of RCRA is to protect human health and the environment. A secondary goal is to con-serve our country’s natural resources. The RCRA attains these goals by regulating all aspects ofhazardous waste management: generation, storage, treatment, and disposal. This concept is re-ferred to as “cradle to grave” waste management.

Solid waste is categorized as:Class One, Hazardous: ignitable, reactive, corrosive, toxicClass One, Nonhazardous: RCRA regulations do not applyClass Two Examples include garbage, cured epoxy resin, biopond filter solidsClass Three Examples include uncontaminated or inert material, “wood”

LawsThe RCRA establishes these penalties: civil penalty of $25,000 a day; criminal penalty for know-ing endangerment, $250,000 and 15 years in jail ($1 million for a company). Liability extends toany person involved in breaking the law.

State water commissions have been organized in each state to regulate and control the solidwaste generated within their boundaries.

PermittingStorage of a hazardous chemical for more than 90 days requires a permit. An ideal facility includes:

• A covered facility to prevent rainwater contamination• No contact with soil• Containment for all equipment• Raised equipment to permit inspection for leaks

15.4 Toxic Substances Control

The Toxic Substances Control Act of 1976 (TSCA) is a federal law that was intended to protecthuman health and the environment. The TSCA was also designed to regulate commerce byrequiring testing and imposing restrictions on certain chemical substances. The TSCA require-ments apply to all manufacturers, exporters, importers, processors, distributors, and disposers ofchemical substances in the United States.

ControlsThe TSCA inventory (a list of 70,000 toxic chemicals) was established to record all products man-ufactured, imported, sold, processed, or used for commercial purposes. Exemptions include R&Dchemicals and by-products without commercial purpose. The TSCA also controls premanufacturereview of new chemical substances, risk assessment by testing and information gathering, record-keeping and reporting on health and environmental effects associated with chemical substances,and restrictions on known hazardous chemicals.

The Toxic Substances Control Act establishes severe penalties for those who break the law.Currently, yearly penalties for violations are estimated at more than $40 million. The EPA is theprimary agency charged with enforcing toxic substance control.

15.4 Toxic Substances Control

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15.5 Emergency Response

In an industrial environment, responding to an emergency is done according to a specific set ofstandards. Emergency response drills are carefully planned and include preparations for worst-case scenarios: for example, vapor releases, chemical spills, explosions, fires, equipment failure,hurricane, high winds, loss of power, and bomb threats or actual bombings.

Programs such as Community Awareness and Emergency Response (CAER) are designed towork with the community while industry utilizes and implements:

• Action plans• Emergency response coordinators and teams• Site-specific drills• Incident reports

15.6 Community Right-to-Know

The community right-to-know principle holds that a community should be aware of the chemi-cals manufactured or used by local chemical plants and business. Legislation, regulations, andprograms based on this principle are intended to involve the community in emergency responseplans, improve communication and understanding between industry and the surrounding com-munity, improve local emergency response planning, and identify potential hazards.

The Comprehensive Environmental Response Compensation and Liability Act (CERCLA) holdsgenerators and disposers of hazardous waste liable for past practices, and established the “Superfund” of $1.6 billion to pay for cleanup operations at abandoned hazardous waste sites. Italso mandated that the public be informed of these sites and the known hazards. Community right-to-know and CAER programs work with CERCLA to protect the community.

The following employ the community right-to-know principle:• CERCLA• Emergency planning and community right-to-know programs• Superfund Amendments and Reauthorization Act (SARA)• Hazard Communication Act (HAZCOM)• OSHA Hazard Communication Act (OSHA HAZCOM)• Material Safety Data Sheets (MSDSs)

Agencies involved include:• Department of Health• State water commission• U.S. Environmental Protection Agency

The goal of all these laws and programs is, very simply, to protect citizens.

Quality StandardsIndustry believes that reducing and recycling wastes at their source are the first priority ofresponsible waste management. Industry has put in place environmental management systems

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to make, use, handle, and dispose of its products safely. Industry is committed to making majorexpenditures in environmental technology to reduce emissions and protect the environment.

Summary

Air pollution is the contamination of the air, especially by industrial waste gases, fuel exhausts, andsmoke. Water pollution is the contamination of the water, especially by industrial wastes.

Solid waste is a by-product of modern technology and is technically defined as a discarded solid,liquid, or containerized gas. This definition includes materials that have been recycled or aban-doned through disposal, burning or incineration, accumulation, storage, or treatment.

In an industrial environment, responding to an emergency is done according to a specific set ofstandards. Emergency response drills include practice for worst-case scenarios.

Legislation, regulations, and programs based on the community right-to-know principle areintended to increase community awareness of the chemicals manufactured or used by localchemical plants and business, involve the community in emergency response plans, improvecommunication and understanding, improve local emergency response planning, and identifypotential hazards.

The purpose of the Resource Conservation and Recovery Act, enacted in 1976, is to protecthuman health and the environment and to conserve our country’s natural resources by regulatingall aspects of hazardous waste management, including generation, storage, treatment, anddisposal. This concept is referred to as “cradle to grave” management.

The Toxic Substances Control Act, a federal law enacted in 1976, was intended to protect humanhealth and the environment. The TSCA was also designed to regulate commerce by requiringtesting and imposing restrictions on certain chemical substances. The TSCA requirements applyto all manufacturers, exporters, importers, processors, distributors, and disposers of chemicalsubstances in the United States.

Summary

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Chapter 15 Review Questions1. Solid waste is technically defined as:

a. a discarded solid, liquid, or containerized gas.b. materials recycled or abandoned through disposal, burning (incineration),

accumulation, storage, or treatment.c. a material composed of 2% hydrocarbons.d. a and b.

2. The community right-to-know principle: (select all correct responses)a. increases community awareness of the chemicals manufactured or used by local

chemical plants and business.b. identifies potential hazards.c. improves communication and understanding.d. improves local emergency response planning.e. involves the community in emergency response plans.

3. The purpose of the RCRA is to protect:a. human health and the environment.b. industrial equipment.c. industrial manufacturers from liability lawsuits.d. a and c.

4. “Cradle to grave” is part of which act?a. Resource Conservation and Recovery Actb. Clean Air Actc. Clean Water Actd. Toxic Substances Control Act

5. Smoking flares in excess of _________ minutes should be reported.a. 3b. 10c. 5d. none of these

6. Vapor releases, chemical spills, explosions, fires, equipment failures, hurricanes, highwinds, loss of power, and bomb threats fall under which main program?

7. What must be obtained for any project that has the possibility of producing air pollutants?

Quality ControlAfter studying this chapter, the student will be able to:

• Define quality control principles and terms.• Describe the principles of continuous quality improvement.• Explain the four phases of the quality improvement cycle (plan, observe

and analyze, learn, and act).• Describe the supplier-customer relationship.• Identify and describe quality tools used in the industry.• Describe statistical process control.• Use flowcharts, run charts, cause-and-effect (fishbone) diagrams,

and Pareto charts.• Describe planned experimentation.• Explain and use histograms or frequency plots.• Describe forms for collecting data.• Describe scatter plots.

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Chapter 16 ● Quality Control

Key TermsCause-and-effect (C&E) diagram (fishbone diagram)—a method for summarizing availableknowledge about the causes of process variation.

Control charts (SPC charts)—statistical tools used to determine and control process variations.

Flowchart—a picture of the activities that take place in a process.

Forms for collecting data—can vary from notes jotted down on a napkin to complex,preprinted documentation tools.

Histogram (frequency plot)—a graphical tool used to understand variability. The chart isconstructed with a block of data separated into 5 to 12 bars or sections from low number tohigh number. The vertical axis is the frequency and the horizontal axis is the “scale of char-acteristics.” The finished chart resembles a bell if the data is in control.

Improvement cycle—a four-phase system for quality improvement: plan, observe and analyze,learn, and act.

Pareto chart—a simple bar graph with classifications along the horizontal and vertical axes.The vertical axis is usually the number of occurrences, cost, or time. The horizontal axis ordersthe bars from the most frequent to the least frequent.

Planned experimentation—a tool used to test and implement changes to a process (aimed atreducing variation) and to understand the causes of variation (process problems).

Run chart—a graphical record of a process variable measured over time.

Scatter plot—chart used to indicate relationships between two variables or pairs of data.

Statistical process control (SPC)—statistical control methodology applied to a process.

16.1 Principles of Continuous Quality Improvement

This section discusses the technology that provides the foundation for quality improvement. Processtechnicians use this technology as a valuable component of the continuous quality improvementteam.

The principles of continuous quality improvement include:• Innovate and improve services, products, and processes• Integrate suppliers and customers into the quality process• Use quality tools

– Statistical process control– Flowcharts– Cause-and-effect diagrams (fishbone diagrams)– Pareto charts– Run charts– Control charts– Planned experimentation

– Histograms or frequency plots– Forms for collecting data– Scatter plots

• Audit and evaluate• Provide continuous quality improvement training to all employees• Make an unrelenting commitment to quality and involve all levels in the organization• Document what you do, and do what you say

16.2 Quality Improvement Cycle

The quality improvement cycle consists of four phases that are continuously re-implemented:plan, observe and analyze, learn, and act (Figure 16–1).

Phase 1: PlanThe first step in the improvement cycle is to increase current knowledge of the process.The more theteam knows about the process, the more likely it is that changes submitted by the team will improvequality. Phase 1 takes a significant amount of time to complete. The planning phase should addressspecific objectives and questions, make predictions, and propose a plan for testing. At the conclusionof Phase 1, the plan that is developed should consider methods, resources, schedules, and people.

Phase 2: Observe and AnalyzePhase 2 implements the data collection process. The data collected is used to address the ques-tions from Phase 1. Data analysis can reveal what is actually happening, and lead to refinementof or changes in the initial questions in Phase 3.

Phase 3: LearnThis phase combines Phase 1 and Phase 2 activities. The results of the data analysis are com-pared to current knowledge and theories to see if contradictions exist.

Phase 4: ActThe results from Phase 3 are used to decide whether a change to the process is required. If achange is required, a modified brainstorming session should be conducted to determine whatchanges to the process would result in improvement. These changes should be stated clearly.

16.2 Quality Improvement Cycle

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ACT PLAN

LEARNOBSERVE

andANALYZE

Phase 1Phase 2Phase 3

Phase 4

Figure 16–1 Improvement Cycle

16.3 Supplier-Customer Relationship

Industrial manufacturers buy raw materials from suppliers to make products for their customers.Com-panies depend on suppliers to provide them with quality raw materials. Customers depend on com-panies to provide them with quality products. In today’s global economy, a new relationship existsbetween suppliers, companies, and customers. Each is dependent on the other for financial success.

Companies are becoming more and more involved with customers and suppliers. Both raw mate-rials and products are tracked from inception. Documentation, quality charts, and external auditsfollow products and raw materials from cradle to grave. Customers are providing more informationabout their needs to companies.

16.4 Quality Tools

Process operators use a number of analytical quality tools to perform their jobs, including:• Flowcharts• Cause-and-effect diagrams (fishbone diagrams)• Pareto charts• Run charts• Control charts• Planned experimentation• Histograms or frequency plots• Forms for collecting data• Scatter plots

16.5 Statistical Process Control

Statistical process control (SPC) is a quality tool based on the principles of statistical mathe-matics and applied to a process to control product quality. The theory of SPC is based on somecomplex mathematics, but you need not be a mathematician to understand how to use the system.

In any process, a certain amount of variability occurs. Variability is defined as the tendency to vary orchange. For example, process equipment does not heat up to 450.5�F and stay at exactly 450.5�F. In-stead, it tends to move a bit lower and higher. These variations occur with temperature, pressure,flows, and levels.Each process has its own variability and ability to tolerate change.SPC identifies thisvariability and enhances an operator’s ability to control the process by setting limits on the variability.

In the past, operators would adjust their equipment based on current readings. If the reading istaken when the normal variation of a process is in a low cycle, the operator’s adjustment will swingthe process variable high. Adjustments made without SPC methodology tend to create or exag-gerate these natural high and low swings.

Customers identify the key target setpoints for the products they require. In-house engineers iden-tify other process variables, such as temperatures, flows, levels, and pressures, that support theability of the process to produce the desired products.

SPC allows normal equipment and process fluctuations to be considered over a longer period oftime. To warrant adjustment, sample results must demonstrate a downward or upward trend awayfrom the key target setpoints.

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Product DirectivesMost companies use a product directive or recipe for each product they make. Product directivesdetail operating parameters and control points such as:

• Correct feed• Temperature and pressure profile• Equipment speed• Additive setpoint• Level and flow setpoints

Sample TypesRaw materials normally are sampled before and during a process run. However, when trouble-shooting problems, it is advisable to catch samples frequently.

Additives. Additives are sampled for purity and conformation to specifications when received atthe warehouse. When troubleshooting control problems, additional samples are taken (caught)from containers being used at the time problems occurred.

Products. Products are sampled for customer specifications. Sampling is performed to confirmthat the process is in control, but sample results also can be a flag for unseen problems.

Typical Sample Tag. A blue tag is used for samples to be processed by the laboratory accordingto the usual procedures. A green tag indicates to the laboratory that this sample should be givenhigh priority. Figure 16–2 shows sample tags.

16.5 Statistical Process Control

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TEST Results

Remarks

MFRColorPPGCalcium StearateBHTIr-1010Ultranox 626

DateGradeSubmitted by

PT774-0001

FINISHING SAMPLE

Lot #

TimeExtruder

REASON FOR PRIORITY

Remarks

DATE

PLASTICS UNIT549-7200A

HIGH PRIORITY START-UP SAMPLE

GRADE CHANGE

EXTRUDER START UP

CHANGE OF FEED

OTHER (LIST BELOW)

GRADE

EXTRUDER

SUBMITTED BY

TESTMELT FLOW RATE @ C230

PU AND CPLTO RECORDSEPARATELY

TIME SAMPLE IN LAB

TIME RESULTS RELEASED

SAMPLE TIME

Blue (Normal) Sample Tag Green (High Priority) Sample Tag

Figure 16–2 Sample Tags

Control ChartsStatistical process control charts (SPC charts) are used to plot quality parameter points fromsamples taken at different times during a run. Even if all of the points are within specifications,when they are plotted on a graph you may see quite clearly that there is a trend that in time willresult in off-specification material unless an adjustment is made. An upset or out-of-control situa-tion is both vividly revealed and documented by such a chart (see Figure 16–3).

SPC GuidelinesSPC guidelines account for normal process deviations and process upsets. (See Figure 16–4.)

16.6 Flowcharts

A flowchart is a picture of the key activities that take place in a process (Figure 16–5). Flowchartsdescribe how the process is actually working today. One of the common mistakes people makewhen flowcharting is to add too much information to the chart. Flowcharts should include action orstep boxes and yes/no decision diamonds.

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EXTRUDERGRADEDATELOTTIMEVALUE

2rr

3r

-rx

-2r-3r

PELLET SIZECOLORTEST BINREC BLENDER

COMMENTS:

KEY ADDITIVE-

COMPOSITES

=======

2rr

3r

-rx

-2r-3r

=======

VALUE

DATE/TIMERESULTS

MFR ADDITIVE

PP00012/20/9899546789

16 18 20 22 0 2 4 6 8 102.2 2.11 2.2 2.17

2.5

QUALITYLIMITS

QUALITYLIMITS

1.8

2.292.22

2.36

2.082.15

2.011.94

IR-1010

0.1370.131

0.143

0.1190.125

0.1130.107

0.167

0.083

35 MIN2 MAX

3-301

0.120 0.120 0.116 0.156 0.134

R 0.156

#1 No apparent assignable cause; made no adjustment (possibly end of mix—higher concentration of IR-1010?)

#1

Figure 16–3 Quality Control Run Chart (Melt Flow Rate)

16.6 Flowcharts

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Evaluation Action

Seven in a row on one side of the target. Action is usually a small setpoint change.Usually indicates a process shift. Using the av-erage of the last two results, adjust according tothe product directive.

Three results in a row or three out of four resultsabove yellow (+1 sigma) or below yellow (-1 sigma).

The three-out-of-four case scenario keeps oneisolated plot point from upsetting the process.Using the average of the last two results, makeadjustments according to the product directive.

Two results in a row or two out of three resultsabove orange (+2 sigma) or below orange (-2 sigma).

Using the average of the last two results, makeadjustments according to the product directive.

One result above/below red (+3 or -3 sigma). A red plot point requires immediate evaluation.Check process trends to see if a significant stepchange occurred. If a shift in the normalprocess is identified, make adjustments ac-cording to the product directive. If the changedoes not look reasonable (no visible change inoperating conditions), resample and send agreen tag to the laboratory. If the green tagresult is in control, disregard the questionableresult and follow normal procedures. If the re-sample confirms the previous result, take theappropriate action and resample after 30 min-utes. If the green tag result is above qualitylimits, divert to off test until the process is backin control.

One result crosses 4 sigma lines. A four-sigma jump requires immediate investi-gation. Check process trends to see if a sig-nificant step change occurred. If a shift in thenormal process is identified, make (+3 or-3 sigma) product directive adjustments. If thechange does not look reasonable (no visiblechange in operating conditions), resample andsend a green tag to the laboratory. If the greentag result is in control, disregard the question-able result and follow normal procedures. If theresample confirms the previous result, take theappropriate action and resample after 30 min-utes. If the green tag result is above qualitylimits, divert to off test until the process is backin control.

Figure 16–4 Statistical Process Control Guidelines

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?

StartDistillation

System

TakeSamples

TakeSamples

TakeSamples

Bad

Bad

Bad

Good

Good

Good

MakeCorrection

StartFeed

System

StartPre-HeatSystem

Line-upColumn

Go toProduct

Tank

FillTank

Moveto

ReactorSystem

Hold-upRe-Test

Hold-upRe-Test

TakeSamples

Bad

Good

Hold-upRe-Test

Pre-HeatFeed

AddChemical

XXX

SendTo

Column#2

Line-upOverhead

Line-upSide

Stream

Line-upBottom

ToStorage

ToCustomers

(END)

Hold

Activitiesin Process

Activitiesin Process

Decision

Decision

Decision

Decision

Figure 16–5 Flowchart

16.7 Run Charts

One of the quality tools most commonly used in industry is a run chart (Figure 16–6). Run chartsare very powerful tools that show a graphical record of a process variable measured over time.The following steps should be used when building a run chart:

• Estimate the expected range of data points.• Develop a vertical scale for the data that uses 50% to 70% of the overall range so the

chart is not too narrow or too wide.• Plot the data over time.

16.8 Cause-and-Effect (Fishbone)

DiagramsAnother important quality tool is a cause-and-effect (C&E) diagram, also called a fishbonediagram (Figure 16–7). Cause-and-effect diagrams organize the causes of variation into general

16.8 Cause-and-Effect (Fishbone)

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240

250

200

180

0.140

0.160

0.120

0.100

Target

Time

Figure 16–6 Run Chart

TECHNICIAN ERROR

Tired Drugs

Training

Inattentive

Trainee

Did not follow procedure

EQUIPMENT FAILURE

Instrument

Equipment pump failed

exchanger leak

air lost transmitter failed

(PEOPLE) (MACHINES)

FEEDSTOCK BAD (MATERIALS)

Feed concentration bad

Additive not available Product too pure

Warehouse delays Weekend

Busy

Procedures

Upset with Co-worker

(METHODS)

Angry with management

New job

Family problems

Wrong procedure

PROBLEM

PROCEDURES

Figure 16–7 Fishbone Diagram

categories: (1) methods, (2) materials, (3) equipment (machines), and (4) human. Each of thesefour sections summarizes available knowledge about the causes of process variation. C&E dia-grams were developed by Kaoru Ishikawa in 1943.

16.9 Pareto Charts

A Pareto chart is a simple bar graph with classifications along the horizontal and vertical axes(Figure 16–8). The vertical axis is usually the number of occurrences, cost, or time. The horizon-tal axis orders the bars from the most frequent to the least frequent. This type of chart takes itsname from a man named Vilfredo Pareto, who pioneered income distribution studies.

16.10 Planned Experimentation

Planned experimentation is a tool used to test and implement changes to a process (aimed atreducing variation) and understand the causes of variation (process problems). (See Figure 16–9.)Global pressures are forcing organizations to meet customer needs, reduce costs, and improve

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Numberof

Occurrences

AB C D EF GH I J KL

Figure 16–8 Pareto Chart

X 3

X 1

X 2

RESPONSE

TEST

XX

X

XX

XX

RESPONSE

_ X 1 +

X 2 -

X 2 +X 2 X 2 X 3 X 3

EFFECTS

Figure 16–9 Planned Experimentation

productivity. Planned experimentation is part of the continuous improvement process. Principlesfor design and analysis of planned experiments include:

• designing new systems that vary from current practices• developing and implementing change• effective changes• rate and extent of product improvement• process improvement• linking systems to change

The principles associated with planned experimentation require change, however, some changesdo not improve the system. Questions generated by planned experimentation include:

• which single condition or parameter do we test first.• how will we recognize if the change is correct.

Changes that create improvement require the use of statistical process experimentation andobservation. This is of course followed up by analysis, design, development, implementation,and evaluation of the change or changes made.

16.11 Histograms or Frequency Plots

Histograms or frequency plots are graphical tools used to understand variability (Figure 16–10).The chart is constructed with a block of data separated into 5 to 12 bars or sections from lownumber to high number. The vertical axis is the frequency and the horizontal axis is the “scale ofcharacteristics.” The finished chart resembles a bell if the data is in control.

16.12 Forms for Collecting Data

The forms used for data collection can range from notes jotted down on a napkin or scrap of paperto complex, preprinted checklists. Forms are very helpful in collecting and organizing raw data.Most operators carry around small notebooks to record information collected during routinerounds. Figure 16–11 shows a sample form for collecting data.

16.12 Forms for Collecting Data

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Scale of the Characteristic

FrequencyX

X X XX X

X

0

3

6

9

30 34 38 42 46 50 54 58 62 66 70

XXXX

XXXX

X

XXXX

XX

XXXX

XX

X

XXXX

XXX

X

XXXX

XXXX

X

XXXX

XXX

Figure 16–10 Histograms

16.13 Scatter Plots

Scatter plots are used to indicate relationships between two variables or pairs of data (Figure 16–12).The easiest way to determine if a cause-and-effect relationship exists between two variables is to usea scatterplot.Variables such as flow rate and temperature can be used in a scatter diagram. In this re-lationship, temperature may increase or decrease as flow rate fluctuates. This response would showup on a scatterplot diagram on the x- or y-axis.The independent variable is typically controllable, whilethe dependent variable is located on the opposite axis.

The steps in setting up a scatterplot include collecting data in ordered pairs. The cause or inde-pendent variable and the effect or dependent variable are placed side-by-side in ordered pairs.A common example of this relationship can be found using miles per hour versus miles pergallon. By increasing the MPH and comparing it to MPG the scatterplot data can be collected.When placed on the chart it becomes clear that as MPH increase, MPG decreases.

Summary

The principles of continuous quality improvement include innovation and improvement of services,products, and processes; integration of suppliers and customers into the quality process; useof quality tools; audit and evaluation; provision of continuous quality improvement training to allemployees, unrelenting commitment to quality and involvement of all levels in the organization;and documentation.

The four phases of quality improvement are plan, observe and analyze, learn, and act. The firststep in the improvement cycle is to increase current knowledge of the process and develop a plan

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Checklist Unit 1 Setpoint Actual

Figure 16–11 Form for Collecting Data

Figure 16–12 Scatter Plots

X

Y

for improvement. Phase 2 implements the data collection process. In Phase 3, the results of thedata analysis are compared to current knowledge to see if contradictions exist. In Phase 4, theresults are used to decide whether a change to the process is required.

Companies are becoming more and more involved with customers and suppliers. Both productsand raw materials are tracked from cradle to grave. Customers are providing more informationabout their needs to companies.

Process technicians use quality tools during normal operations. Statistical process control is aquality tool based on the principles of statistical mathematics. Control charts are used to plot qual-ity parameter points from samples taken at different times during a run. A flowchart is a picture ofthe key activities that take place in a process and describes how the process actually works today.Run charts are powerful tools that show a graphical record of a process variable measured overtime. Cause-and-effect diagrams organize the causes of variation into general categories: meth-ods, materials, equipment, and human. Pareto charts, planned experimentation, forms for collect-ing data, and scatter plots are other tools used in quality improvement.

Summary

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Chapter 16 Review Questions1. List five quality tools.

2. Describe the improvement cycle.

3. What type of quality chart is a picture of activities that take place in a process?

4. The principles of quality improvement include all of the following except:a. quality toolsb. contingency perspectivec. audits and evaluationsd. innovation and improvement of services and products

5. Which of the following is not a quality chart?a. controlb. flowc. Paretod. Gantt

6. What do the initials SPC stand for?

7. Which chart uses quality methodology to control a process?a. flowb. Paretoc. rund. SPC

8. Name four charts that work with process variation.

9. What is another name for a fishbone chart?

10. Planned experimentation is:a. a tool used to test and implement changes in a process.b. a tool designed to reduce variation.c. a tool designed to help operators understand process variability.d. all of the above.

Process TroubleshootingAfter studying this chapter, the student will be able to:

• Describe the various troubleshooting methods.• Identify and describe the various troubleshooting models.• Describe how different variables affect each other.• Explain how problems with process equipment affect other systems.• Analyze process problems and provide solutions.• Troubleshoot specific operational scenarios.• Describe the varied instrumentation used to troubleshoot process problems.• Distinguish between primary and secondary problems.• Collect, organize, and analyze data.• Respond to alarms and control systems that are outside operational guidelines.• Compare troubleshooting methods and models.

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Chapter 17 ● Process Troubleshooting

Key TermsControl loop—system consisting of a collection of instruments that work together to controlpressure, temperature, level, flow, and analytical variables. Information from control loops isinvaluable in the troubleshooting process.

Equipment failure—occurrence when equipment has broken, ruptured, or is no longerresponding to its design specifications.

Fail open/fail closed—term used in troubleshooting that describes how a control valve ceasesto work (fails): in the open or the closed position.

Primary operational problem—term for the first issue (problem) that created a processupset.

Process flow diagram (PFD)—graphic chart used in troubleshooting to quickly identify theprimary flow path and the control instrumentation being used in the process.

Process variables—changeable conditions (variables) that can be detected by instruments andthat provide clues to what is occurring within the “big picture” of the entire process.

Secondary operational problems—issues created or responded to during a process upsetother than the primary problem.

Troubleshooting methods—means of diagnosing process problems; include educational,instrumental, experiential, and scientific.

Troubleshooting models—tools used to teach troubleshooting techniques. Basic models includedistillation, reaction, and absorption and stripping, or combinations of these three.

17.1 Troubleshooting Methods

Troubleshooting the operation of process equipment requires a good understanding of basiccomponents and how the equipment operates. Equipment used in modern manufacturing is run24 hours a day, 7 days a week, 52 weeks a year. Routine maintenance is performed on thisequipment during scheduled maintenance times.

Plants that build redundancy into their processes provide backup systems for critical equipment.For example, pumps and compressors typically have two or three backups. Process techniciansshould attempt to uncover as much information as possible about the equipment used in theirunits. Much of this information can be found in technical manuals or the operating manuals. Man-ufacturer information is typically included in the engineering specifications, drawings, and equip-ment descriptions.

Data collection, organization, and analysis can be used to troubleshoot process problems. Check-sheets are used to collect large quantities of data. This quantitative data can be organized intographics or plotted as trends to discover process variation or changes. Data analysis utilizes avariety of quality techniques to put all of the parts in place.

A number of troubleshooting methods can be used with any of the troubleshooting models.Methods employed vary depending on the individual educational faculty, consultants, andindustry. The basic approach to most methods includes the development of a good educationalfoundation.

Method One: EducationalTo do competent troubleshooting, a process technician should have:

• Basic knowledge of the equipment and technology• Understanding of the math, physics, and chemistry associated with the equipment• Studied equipment arrangements in systems• Studied process control instrumentation• Operated equipment in complex arrangements• Studied troubleshooting of process problems

Troubleshooting is a process that requires a wide array of skills and techniques. The primary goalis to control variables such as temperature, pressure, flow, level, and analytical variables. Thisrequires the use of modern control instrumentation such as indicators, alarms, transmitters, con-trollers, control valves, transducers, analyzers, interlocks, and so on. With these instruments, it ispossible to control large, complex processes from a single room.

In these types of systems, process setpoints and process variables on controllers should beclearly related and reflect each other. Process problems are quickly identified when these two donot align. For example, if the flow rate is set at 200 gpm and the process variable is 175 gpm, a25-gpm difference exists. This could indicate a serious problem.

Method Two: InstrumentalThe instrumental method of process troubleshooting involves:

• Basic understanding of process control instrumentation• Basic understanding of the unit process flow plan• Advanced training in controller operation (PLC and DCS)• Knowledge of process-problem troubleshooting

Method Three: ExperientialThe experiential method of process troubleshooting involves:

• Experience in operating specific equipment and systems• Familiarity with past problems and solutions• Ability to think “outside the box” (use creativity and imagination)• Critical thinking, especially in identifying and challenging assumptions• Evaluating, monitoring, measuring, and testing alternatives

Method Four: ScientificScientific methods of process troubleshooting are grounded in principles of mathematics, physics,and chemistry; they apply scientific theory to operations. A scientific method:

• Requires a good understanding of equipment design and operation• Views the problem from the outside in


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• Uses outside information and expertise and reflective thinking• Generates alternatives, does brainstorming, and ranks alternatives

Troubleshooting Process Problems1. In Figure 17–1, what will happen if P-104 fails and cannot be restarted?

a. Steam flow will b. Bottom flow rate willIncrease IncreaseDecrease DecreaseStay the same Stay the same

c. Bottom temperature will d. Bottom level willIncrease IncreaseDecrease DecreaseStay the same Stay the same

The questions that are developed for troubleshooting scenarios can vary from equipment failure toinstrument failure. Each of these simulated failures provides good experience for the new technician.Collecting and organizing these scenarios is a difficult process that takes time and effort. In Figure 17–1, the steam flow will increase, the bottom flow rate will decrease, the bottom tempera-ture will decrease, and the bottom level will increase. Why?

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Figure 17–1 Basic Troubleshooting 1

P-104

I/P

FT

FIC

PVSPOP%

PVSPOP%

Flow Controller

I/P

LT

LIC

LE

Fi

PVSPOP%

Level ControllerTE TT

TIC

SteamIn

ToBoiler

BottomProduct

103

50

Tray 1

Tray 2

Tray 3

Tray 4104

12

220

102

C-100

2. In Figure 17–2, what will happen if the reflux control valve fails to close?a. Column pressure will b. Reflux flow rate will

Increase IncreaseDecrease DecreaseStay the same Stay the same

c. Column top temperature will d. Level in D-100 willIncrease IncreaseDecrease DecreaseStay the same Stay the same


359

I/P

FT

FIC

Fi

PVSPOP%

TE TT

TIC

AT2

I/P

FT

FIC

I/P

LTLIC

LE

Fi

PVSPOP%

Level Controller

Flow Controller

PVSPOP%

Temp Controller

PVSPOP%

Flow Controller

PIC I/P

PE

PT

PVSPOP%

Pressure Controller

Tray 8

Tray 7

Tray 6

Tray 5

Tray 4

D-100

P-103

101

103

102

400

100

130

50

160

105

102

Reflux

Cascade

Figure 17–2 Basic Troubleshooting 2

In Figure 17–2, the column pressure will stay the same, the reflux flow rate will increase, the col-umn top temperature will go down, and the level in D-100 will decrease. Technicians should studythese problems and ask why a specific control loop responds in a certain way. Note that controllersin AUTO (automatic), MAN (manual), and Cascade modes will respond differently in operation.

Systematic Approach to Teaching TroubleshootingTo troubleshoot effectively, a technician needs to know whether a control valve fails open (FO) orfails closed (FC).When an automated valve is installed in a unit or process, the engineers take intoaccount whether that valve should fail open or fail closed. Each valve operates differently; forexample, when a valve is designed to fail closed, a heavy spring causes the flow control elementto move to the closed position. It takes instrument air to open the valve. A fail-closed valve wouldassume the following positions:

Fail Closed (FC)

0% Closed

25% 25% open

50% 50% open

75% 75% open

100% 100% open

When a valve is designed to fail in the open position, like an emergency water system, the valvewill respond as follows:

Fail Open (FO)

0% 100% open

25% 75% open

50% 50% open

75% 25% open

100% closed

Figure 17–3 compares these two systems—fail open/fail closed—and illustrates how eachworks.

17.2 Troubleshooting Models

One of the highest levels a process technician can achieve is the ability to clearly see the processand sequentially break down, identify, and resolve process problems. Process troubleshooting hastraditionally been considered the domain of senior technicians; however, some people believe thatsuccessful techniques can be taught to all technicians. Experience has proven over time to be thebest teacher on equipment that is manually operated, although new computer technology providesadvanced control instrumentation that can be used to quickly and methodically track down processproblems. It is well known that a single problem can have a cascading effect on all surroundingequipment and instrumentation. This phenomenon is commonly associated with primary andsecondary operational problems.

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17.2 Troubleshooting Models

361

Figure 17–3 Fail Open and Fail Closed

FT

I P

AUTO

225 GPM0.0 GPM

100%

SPPVOP%

FC

FT

I P

FIC

AUTO

225 GPM0.0 GPM

0.0 %

SPPVOP%

FO

0% Closed 25% 25% open 50% 50% open 75% 75% open 100% Full open

Pump Failed

Pump Failed

Fail Closed

Fail Open

0% 100% open 25% 75% open 50% 50% open 75% 25% open 100% Closed

FIC

Troubleshooting models are literal, physical demonstrations of the equipment and systemspresently being taught in community colleges and universities. Some of these models are thereaction model, the absorption and stripping model, the separation model, and the distillationmodel. These models are completely outfitted with alarms, analyzers, interlocks, permissives,video trends, recorders, and control instrumentation. Process problems can be simulated usingthese models.

A good college curriculum includes the use of advanced computer system software that closelysimulates console operations. Software companies like Advanced Training Resources (ATR®) areleading the way in the development of this type of software and computer systems. Some college

training systems have modern control instrumentation mounted on operational pilot units.Students using these types of systems receive true hands-on experience.

The 11 models used to teach process troubleshooting are:• Pump and tank model• Compressor model• Heat exchanger model• Cooling-tower model• Steam-generation model• Furnace model• Distillation model• Reaction model• Separation model• Absorption and stripping model• Combination of the preceding models

These 11 models provide the hardware to which, or framework within which, the various trou-bleshooting methodologies are applied. Each model has a complete set of process control instru-mentation and equipment arrangements. A complete range of troubleshooting scenarios has beendeveloped for educators and typically accompanies these models. It should be noted that thesemodels are only the more common used by educators. Many other models can be used, depend-ing upon the background and experience of the educators and the resources available to theeducational program or facility.

17.3 Basic Equipment Troubleshooting

Troubleshooting the operation of process equipment requires a good understanding of basic com-ponents and how the equipment operates. Knowledge of the routine maintenance schedule, theredundancies built into the process, and the location of information about the process is essentialfor effective troubleshooting.

Data collection, organization, and analysis are equally important parts of troubleshooting processproblems. Process flow diagrams (PFDs) are used to quickly identify the primary flow path andthe control instrumentation being used in the process. Checksheets are used to collect data thatcan be graphically organized or charted to show trends and reveal process variation or changes.Data analysis utilizes a variety of quality techniques to pinpoint process problems and potentialissues.


Figure 17–4 shows process control instrumentation being used to control each process variableon a column. The level in the bottom of the column and the overhead accumulator must be con-trolled at 50%. The thermosyphon reboiler maintains the energy balance on the column at a settemperature. The bottom and the top temperatures form a gradient. Flow to the column and refluxlines allows the system to operate in automatic mode. Pressure is held at specified values on the

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overhead accumulator. This has an effect on the entire distillation column even though pressuresand temperatures will vary slightly throughout the column.

Figure 17–4 shows how all of these control loops would be located in the system. Process tech-nicians can monitor the response of these systems from the control console. The various types ofinstruments and control loops allow process technicians to operate larger and more complexprocesses.

17.5 Pump Model

The primary purpose of a pump system is to move a product from one place to another. Movingliquids is a common practice in the chemical processing industry, and new process techniciansare given detailed instruction on the basic components found in a pump system. This includes

17.5 Pump Model

363

TE TT

LT LE

TC I/P

PT

PE

PC I/P

I/PI/P

I/P

FT

FTTTFC FC

TC

TE

I/PLTLE LC

LC

Pressure Control Loop

Cascade

Flow Control Loop

Flow Control Loop

Level Control Loop

Level Control Loop

Temperature Control Loop

Figure 17–4 Control Loops

training in the basic types of pumps and their individual components, types of valves and compo-nents, piping, various tanks and vessels, and heat exchanger identification.

Unfortunately, it is far more difficult to teach apprentice technicians how to perform complex pumpline-ups, troubleshoot pump problems, switch pumps on the fly, change line-ups while the pumpis on line, and identify potential problems from operational data. Using the pump model as atraining tool, a college professor has a much larger platform to work from.

The basic equipment components found in a pump system include:• Two pumps—one primary and one backup• Piping and valves• Feed tank• Process control instrumentation—control loops, analyzers, instruments

Figure 17–5 shows the basic components of a pump model. A variety of troubleshooting scenar-ios can be applied to this simple model.Variations depend on the instructor’s experience and ques-tions generated by the students.

364


FT

I P

Pi

FR

FIC

AT

AUTO

40 psig

Pump

LA

1

Ti 80ºF

38 %

225 GPM

225 GPM

99.5%

SP PV OP%

TV AV

TV AV

TV AV

Pi

FT

I P

FIC AUTO

CASC

FC

FC

225 GPM SP PV OP%

50%

0.0%

75%

closed

SP PV OP%

LE

LT

ST

(Feed Tank)

LIC

135 psig

NPSH

NPDH

Mixer

SIC 650 RPM

TV AV

75% TV AV

TV AV

TV AV

TV AV

To Flare

Hi

Lo

200ºF @ 150 psig

CODE STAMP

162,000 GALLONS 12 Hr. reserve @ 225 gpm

1250 rpm

85%

65%

Figure 17–5 Pump Model

17.6 Compressor Model

The compressor system is critical to modern process control. Air systems provide clean, dry airthat is used to open valves and control the flow rate of liquids and gases in the process industry.Compressors are also used to transfer nitrogen, hydrogen, argon, natural gas and other hydro-carbon gases, chlorine, carbon monoxide, carbon dioxide, helium, pure oxygen, and many otherspecialty gases. In the plastics industry, compressors are critical in the transfer of solids, such asgranules, flakes, powder, and additives. The primary purpose of a compressor is to compressgases to create energy to transfer the gas from one place to another.

Apprentice technicians typically study the various compressors found in industry and should beable to identify critical components. Included in this study are discussions on the scientific princi-ples associated with the operation of a compressor, however, operating a compressor system is amuch more complex undertaking. Very few colleges actually have a complete compressor systemon which each apprentice technician has an opportunity to train and qualify for start-up, mainte-nance, data collection, troubleshooting, and shutdown. This is a gap in the system, but the trou-bleshooting model allows instructors some flexibility to discuss and illustrate operationaltechniques.

The basic equipment components found in a compressor model include:• Compressor and receiver• Piping and valves• Dryers• Process control instrumentation

Figure 17–6 shows the basic components of a compressor model. A variety of troubleshootingscenarios can be applied to this simple model. Variations depend on the instructor’s experienceand questions generated by the students.

17.7 Heat Exchanger Model

The primary purpose of heat exchangers in the chemical processing industry is to heat or coolprocess flows. Heat energy flows from hotter areas to colder areas and moves via conductive andconvective heat transfer. A shell-and-tube heat exchanger has a cylindrical shell that surrounds atube bundle. Fluid flow through the exchanger is referred to as either tube-side flow or shell-sideflow. A series of baffles supports the tubes, directs flow, decreases tube vibration, increases ve-locity, creates pressure drops, and protects the tubes. This enhances the heat transfer process.Differences in baffle arrangement produce a variety of fluid flow patterns, mostly turbulent. Fluidflow in heat exchangers is often described as cross flow, counter flow, or parallel flow. Heatexchangers are used in almost every process facility.

Heat exchangers are classified as:• Shell-and-tube

– pipe-coil– double-pipe– hair-pin

17.7 Heat Exchanger Model

365

366



Dryer-1


100 psig

0.0%

Air-to-open

SPPVOP%

IP

PE

PTPIC Pi

PiPi

Pi

100 psigAirinlet

ON

OFF

Dryer-2

PCV

Drum

125 psig

100 psig

Max

Steam

3000 RPM

TV OpenClosed

0 psig0 psig

AV

TVAV

ClosedClosed

TVAV

TVAV

100 psigTVAV

TVAV

FC

20 psig

15 psig

Regulator Setat 3-15 psi

Supply Pressure

Figure 17–6 Compressor Model

– fixed-head or floating-head– single-pass or multipass– u-tube– reboilers—thermosyphon or kettle

• Plate and frame• Spiral• Air-cooled (fin fans)

Process technicians carefully review the various designs and components associated with heatexchanger systems. Work with heat exchangers carries serious responsibilities, because anincorrectly aligned heat exchanger can turn into a bomb. Most college programs spend significanttime working with apprentice technicians as a group; unfortunately, individual, one-on-one, hands-ontraining is not possible. However, the heat exchanger model allows college professors toindividually review and evaluate apprentice technicians on complex line-ups and troubleshootingscenarios.

The key scientific principles associated with the operation of a heat exchanger system include:• Temperature—preheat, condenser, reboiler, conversions• Heat transfer—conductive, convective• Tube growth—expansion• Pressure—delta, inlet, outlet• Fouling• Boiling points• pH of water• Fluid flow—turbulent, laminar, parallel, cross-flow, counter-flow• Flow rates• Electricity for pumps and instruments• Modern process control• Chemical properties

The primary equipment components in a heat exchanger system include:• Multiple pumps—shell inflows and shell outflows• Piping and valves• One or two heat exchangers• Process control instrumentation

Figure 17–7 shows the basic components of a heat exchanger model. A variety of troubleshoot-ing scenarios can be applied to this simple model. Variations depend on the instructor’s experi-ence and questions generated by the students.

17.8 Cooling-Tower Model

The primary purpose of a cooling tower is to cool water.This accomplished primarily through evap-oration or convective heat transfer. As water is pumped into the plant, it picks up heat energy. Hotwater is routed to the cooling tower so that it can be cooled and returned to the operating units.Cooling towers are classified by how they produce airflow, and how they produce airflow in rela-tion to the downward flow of water. A cooling tower can produce airflow mechanically or naturally.After airflow enters the cooling tower, it can cross the downward flow of water or run counter to thedownward flow of water.

Cooling towers are classified as:• Atmospheric-draft• Natural-draft• Forced-draft, counter-flow• Induced-draft, cross-flow

The key scientific principles associated with the operation of a cooling tower include:• Evaporation• Heat transfer and temperature• Relative humidity• pH of water• Fluid flow of water and air• Parts per million (ppm) and coagulants—water quality

17.8 Cooling-Tower Model

367

368


FT

I P

Ti

Pi

FR

FIC

AT

TR

Hot Oil Insulated Tank

AUTO

AUTO

AUTO

180ºF 180ºF

FC

FC

180.5 ºF

40 psig

TAH 100

Ti 115ºF Ti

Fi

Ti 80ºF

Pi

Pi

38 %

Unit Feed

Bottom Product

0.0 %

SP PV OP%

225 GPM 225 GPM

99.5%

SP PV OP%

Heat Exchanger

I P

TIC TE TT

Pi

Pi 35 psig

195ºF

173ºF

130 psig

135 psig

135 psig

625 GPM

1

TV AV

TV AV

TV AV

TV AV

TV AV

TV AV

TV AV

TV AV

TV AV

TV AV

TV AV

TV AV

TV AV

TV AV

Figure 17–7 Heat Exchanger Model

• Pressure• Biocides and algaecides—prevent biological growth• Draft—induced, forced, atmospheric, natural• Electricity• Modern process control

The study of cooling towers takes place primarily in the classroom. Students focus on the dif-ferent designs and various components found there. Hands-on experience is difficult to come byin the college instructional setting. Some classrooms have small models that have been auto-mated for process control; however, this is the exception to the rule. Most college systems havesmall cooling towers that are used with the temperature control systems. Students are allowedto view and tour these devices, but it is not possible for students to operate these devicesbecause they are in operational service. For this reason, the cooling-tower model offers studentsand professors opportunities to memorize start-up procedures and setpoints, operate the model,and troubleshoot process problems. The scope of the instruction on troubleshooting cooling-tower processes is limited only by the time allowed to cover the topic and the background ofthe faculty. It should be noted that a cooling-tower system includes a number of inherent safetyhazards, including hot water, chemical additives, slipping hazards, rotating equipment, andelectrical hazards.

The basic components of a cooling tower include:• Concrete water basin• Splash bars or fill• Pump• Make-up water• Water distribution system• Air louvers• Drift eliminators• Support structure—plastic or pressure-treated• Fan and motor (optional)• Piping• Heat exchangers• Hot-water return header• Blow-down• Chemical additive controls• Modern process control instrumentation and control loops

Figure 17–8 shows the basic components of a cooling-tower model. A variety of troubleshootingscenarios can be applied to this simple model. Variations depend on the instructor’s experienceand questions generated by the students.

17.9 Boiler Model

A steam-generation system is a complex arrangement of equipment and subsystems designedto produce clean, dry steam for industrial applications.The industrial steam produced from boilers

17.9 Boiler Model

369

has hundreds of applications in the processing industry. Steam is typically produced in high,medium, and low pressures. When the burners are lit in a boiler, hot combustion gases beginto flow over the steam-generating tubes, riser tubes, downcomer tubes, and drums. Radiant,conductive, and convective heat transfer begins to take place. Hot combustion gases flow outof the firebox, into the economizer section, and out the stack. Fans provide airflow through thefurnace, creating a negative draft. (Because the furnace is hotter than the outside air, significantdensity differences exist.) Water temperature increases at controlled rates as pressure buildsinside the large upper steam generating drum. As the temperature of the water inside the gener-ating and riser tubes increases, the density of water decreases and natural circulation is estab-lished. Bubbles form, break loose, and rise through the tubes, picking up additional heat energythrough kinetic motion, conduction, and radiant heat transfer. When the pressure increases toslightly above the system pressure setpoint, steam will flow to the header. Inside the upper steam-generating drum, steam and water come into physical contact, saturating the steam. This wetsteam exits the steam drum and is directed through tubes back into the furnace where thetemperature is significantly increased.This process, called superheating, dries out the steam andincreases the pressure. The relationship between steam pressure and temperature can be foundin a steam table.

370


TR

IP

IP

AIC AIC

LIC

25%

25%

25%

30 PPMSPPVOP%

4.5SPPVOP%

7.8 pHSPPVOP%

25%

75%SPPVOP%

100%

125ºF

125ºF

128ºF

SPPVOP%

0.0%

60ºFSPPVOP%

100%

525gpm

525gpm

SPPVOP%

25%

On

Off

SPPVOP%

TE

Ti

TT

FE

FT

TIC

Ti

Pi

Pi

Fi

AEAE

TT

LT

AT AT

AE

AT

TE

IP

IP

TIC

FIC

SIC

IP

IP

AIC

IP

1250RPM

COOLING TOWER

Ti

LA

Low PressureSteam

Condenser

Hi

Low

85ºF

50 psig

45 psig

85ºF

SEST

TVAV

TVAV

TVAV

TVAV

TVAV

TVAV

TVAV

FC

FC FCFC

FC

FC

FC

FC

Figure 17–8 Cooling-Tower Model

A number of hazards are associated with the operation of a boiler system. Some of these hazardsinclude:

• Hazards associated with high temperature steam, “burns”• Hazards associated with using natural gas• Hazards associated with leaks• Instrument failures• Confined Space Entry permit• Opening blinding permits• Isolation of Hazardous Energy permit “Lock-out, Tag-out”• Routine work• Hazards associated with lighting burners• Exceeding boiler temperatures or pressures• Hazards associated with using water treatment chemicals• Error with valve line up resulting in explosion or fire

Many other potential hazards exist beyond those in the preceding list; this is why careful trainingis required for all new technicians assigned to utilities. The focus in the classroom is on the vari-ous types of steam-generation systems and the hundreds of components that make up any steam-generation system. College faculty use videotapes and other instructional materials, and conductplant tours to show students what these systems look like. Unfortunately, the same problem thatexists with the other major areas exists with steam-generating systems as well: Hands-on oppor-tunities are rare and limited and are not available to all of the students in the program. The boilermodel offers a systematic approach to learning that gives apprentice technicians and faculty theopportunity to discuss the very complex operational and troubleshooting scenarios that arise witha steam-generating system.

Figure 17–9 shows the basic components of a steam-generation (boiler) model. A variety of trou-bleshooting scenarios can be applied to this simple model. Variations depend on faculty experi-ence and questions generated by apprentice technicians.

17.10 Furnace Model

A furnace, or fired heater, is a device used to heat up chemicals or chemical mixtures. Furnacesconsist essentially of a battery of fluid-filled tubes that pass through a heated oven. These devicesprovide a critical function in the daily operation of the chemical processing industry. Process heatersare more technically defined as combustion devices designed to transfer convective and radiant heatenergy to chemicals or chemical mixtures.These heaters are typically associated with reactors or dis-tillation systems. Process heaters come in a wide variety of shapes and designs, but the basic stylesinclude cabin, box, and cylindrical.The various parts of a process heater include a radiant section andburners, a bridgewall section, a convection section and shock bank, and a stack with damper control.Modern control instrumentation is used to maintain these rather large and elaborate systems.

The primary means of heat transfer in a fired heater are radiant, conduction, and convection.Radiant heat transfer accounts for 60% to 70% of the total heat energy picked up by the charge inthe furnace. Convective heat transfer accounts for about 30% to 40% of the total heat energy

17.10 Furnace Model

371

picked up in the furnace. Conductive heat transfer processes occur in each of these areas;however, it is easier to measure temperature differences in the actual charge than to calculate theconductive heat transfer coefficients. For heat transfer in the firebox or radiant section, the great-est efficiency is obtained when maximum furnace temperatures are achieved. Decreasing excessair in the furnace maximizes radiant heat transfer. Therefore, controlling excess oxygen in the fur-nace is the single most important variable affecting efficiency.

Excess airflow will decrease furnace temperatures around the burners and force the automaticcontrols to increase natural-gas flow rates to the burner, wasting supplies and money. As hotcombustion gases rise, cooler air is entrained, causing the temperature to decrease. Excess airenhances this process. When excess air enters the burner through the primary and secondary airregisters, a temperature shift occurs as heat is moved away from the burners. Higher temperaturesare created in the upper section of the firebox due to the reduced heat transfer in the lower section.Temperatures in the convection section and stack will also rise significantly. This will reduce theamount of heat available for heating the hot oil and more fuel will have to be burned to maintainprocess specifications.

The basic components of a furnace system include:• Firebox and refractory material• Radiant and convection tubes• Soot blower

372


FICFIC

LIC

Ti

Pi

PR

o

PIC

Burner

o

PIC

FIC

TR

Fan

Fan

Natural Gas Tank

Deaerator

Treatedwater

LPSteam

FT

FE

PT

PT

PE

PE

AUTO

AUTO

25%

50%SPPVOP%

50%

50%SPPVOP%

25%

50%SPPVOP%

0.0 %

-.05

-.02

-.02

SPPVOP%

120 psig

120 psig

25%

SPPVOP%

50%

100%

SPPVOP%

150 GPM

25%

SPPVOP%

Steam Generation Model

404

PiTE

TE403

TE

TE

450ºF

305ºF

350ºF

600ºF

500ºF

IP

350ºF

FT

LT LE

FEFTFE

IP

IP

BA

Pi

Pi 60 psigPi 155 psig

PA

LR

LAL

IP

Hi

LowPA Hi

Low

LR

LAL

35%

35%

Ai

AA Hi

Low0-10% Oxygen

0-10%

IP

v-41

Desuperheated

Superheated

º

50 psig

150 psig 100 psig

75 psig

60 psig

on

Stack

LIC

LT LE

IP

Vent

TVAV

TVAV

TVAV

TVAV

TVAV

TVAV

TVAVTV

AV

TVAV

TVAV

TVAV

TVAV

TVAV

TVAV

FCFC

FC

FC

FC

FO

Figure 17–9 Steam-Generation (Boiler) Model

• Stack damper• Burners• Bridgewall section• Fuel system• Forced-draft process heater• Shell• Radiant section• Convection section• Stack• Fans• Primary and secondary air• Advanced process control instrumentation and control loops

Figure 17–10 shows the basic components of a furnace model. A variety of troubleshootingscenarios can be applied to this simple model. Variations depend on faculty experience andquestions generated by apprentice technicians.

17.10 Furnace Model

373

TE

TE

TE

TE

TT

AE

PTPE

Pi

FT

IP

Ti

Pi

AT

Pi

Pi

H/LTA

TAH

TR

PR

FR

o

PIC

FIC

FIC

FIC

IP

PIC

AIC

AIC

FT

FTFE

IP

TIC

IPPT

PE

TR

Pi

o

IP

AE

AT

Fi


800 gpm

800 gpm

FO

425ºF

395ºF

385ºF

375ºF168ºF

70ºF

350ºF350ºF

Hi 365ºF

Low 335ºF

55psig

55psig

55psig

10 psig

Cu Ft/min

low NOxBurner

IP

Steam

Furnace

35 PSIG

15 psig

12,500 MBH

FC

FC

FC

FC

FC

FC

HeatedAir

inch of water-.05-.05

-.Slight Negative

-.Slight Negative

Slight Negative

0.2 in H2O

0.5 in H2O

Ti

350ºF

BA1

LA

LIC

1

IP

LT

LE

50%

0.0%

25%

25%

25%

0%

25%

50%

25%

100%

OILSUPPLY

Hi-85%Lo-65%

PAHi-65Lo-45

SPPVOP%

SPPVOP%

SPPVOP%

SPPVOP%

SPPVOP%

SPPVOP%

SPPVOP%

SPPVOP%

TVAV

TVAV

TVAV

TVAV

TVAV

TVAV

TVAV

TVAV

TVAV

TVAV

TVAV

TVAV

TVAVTV

AV

TVAV

TVAV

Figure 17–10 Furnace Model

17.11 Reactor Model

The purpose of a reactor is to make, break, or make and break chemical bonds to form newproducts. A reactor is a vessel in which a controlled chemical reaction takes place. The thingsthat have an effect on a chemical reaction are called reaction variables. The design and oper-ation of a reactor enhance molecular contact between four reactants: pentane, butane, liquidcatalyst, and solvent. Feed to the reactor is controlled at 36.5 gpm. The composition of feedfrom the column is 38% liquid catalyst, 61% butane, and 1% pentane. Solvent feed to thereactor is controlled at 68 gpm. The materials in the reactor are chilled to 120�F at 85 psig.The reactants are designed to form a new product with an excess of pure butane. Theconcentration of reactants in the reactor has a major effect on how fast the reaction will takeplace, what products will be produced, and how much heat will have to be added to or takenaway from the reaction. A separator is used to remove the new products and isolate the butanefor storage.

The reactor model (Figure 17–11) provides a framework on which to develop a series of trou-bleshooting scenarios. Problems presented develop from simple to complex as students learnone section and move to the next. Educators use this model to teach one part of a much largerprocess; it is possible to create a multiprocess plant within the walls of the classroom to be usedfor study.

Troubleshooting a reactor system requires the student to become familiar with the typical opera-tion of the unit. As equipment and instrumentation fails, the student sees the cascading effect asingle problem can have on the unit. A single problem can create a series of other problems, sostudents must learn to identify the primary problem that started the system failure(s).

Some of the scientific principles associated with the operation of a stirred reactor include:• Pressure• Heat transfer and temperatures• Fundamental chemistry• Chemical reactions and chemical bonds

– exothermic, endothermic, replacement, neutralization– chemical equations– mass relationships

• Fluid flow– controlled flow rates of solvent, reactants, catalysts, and products

• Mixtures, compounds, solutions• Agitation• Catalysts• Electricity—motors and instrumentation• Modern process control

Process variable alarms can be activated by analytical (composition), pressure, temperature, flow,level, and time variables. Rotational speed on the agitator may be fixed or variable. A series of in-terlocks, permissives, and alarms will engage during operation and will provide a support networkfor the technician. A series of process video trends will be displayed to track each of the criticalvariables. Samples are taken frequently to ensure product quality. Stirred reactors are connectedto off-specification (off-test) systems that allow flexibility in switching between prime and off-test

374


17.11 Reactor Model

375

PIC

Flare

AIC

LIC

TIC

Water FIC

I P

FT

FE

AUTO

FC

85 psig 85 psig

25%

SP PV OP%

250 RPM

250 RPM

25%

SP PV OP%

FT

AT FIC

68 gpm

68 gpm

50%

SP PV OP%

36.5 gpm 36.5 gpm

25%

SP PV OP%

75% 75% 75%

SP PV OP%

120ºF 120ºF 50%

SP PV OP%

50%

21% 21%

SP PV OP%

Pi

88 psig

I P

Feed (Solvent)

Reactor

I P

TE

AT AE

PT

PE

TT TR

TA

LE

LT

I P

Pi

To Separator

I P

Liq-Cat/Pentane/Butane (Feed)

130 psig

104.5 GPM

Butane

38% Liquid Catalyst 14 gal. 61% Butane 22.1 gal. 1% Pentane .4 gal.

61%

Pump

ST

SIC

Mixer

Fi

2.5 Cuft/min

Hi-140ºF

Lo-110ºF

PR PA Hi-100psig

Lo-75 psig

LR LA Hi-90%

Lo-65% AR AA

Hi-28%

Lo-17%

Figure 17–11 Reactor Model

operations. An automatic shutdown allows a technician to push one button and shut down thesystem in the event of a runaway reaction or emergency.

The reactor has a stainless-steel shell designed to withstand temperatures in excess of 500 psigat 650�F. A dimpled water jacket is used to maintain the temperature at 120�F to maximize reac-tion rates. Product agitation is maintained by a mixer at 250 rpm.The composition of the feed to thereactor is 1% pentane, 38% liquid catalyst, and 61% butane. A solvent (toluene, C7H8) isintroduced to the reactor and blended with the column feed. Unlike other processes, the solvent

(toluene) and liquid catalyst react with the butane and pentane to form a new product that isseparated in the separator. The liquid catalyst enhances the separation of butane and pentane inthe column and is easily separated on a tray; however, once the liquid catalyst is exposed to thebutane and pentane feed, it is slightly modified at the molecular level. The operating conditions inthe reactor also promote this process. The agitation process in the reactor is a critical variableresponsible for the reaction that forms a new product.

Problems associated with operation of a reactor include:• Feed composition changes• Concentration increase—increases reaction factors• Agitation problems—will reduce reaction• Loss of cooling water—temperature will increase• Loss of level control• Instrument problems• Loss of pressure control—increase or decrease• Reaction time in reactor—reaction incomplete• Column and solvent flow rates• Temperature increase—doubles reaction rate for every 10�C increase• Loss of catalyst—reaction will stop

17.12 Absorption and Stripping Model

The absorption and stripping model (Figure 17–12) uses two plate distillation columns to separatevaporized catalyst and return it to the reactor. This feedstock is a vapor by-product of the stirredreactor. An absorbent enters the top of the absorption column and flows down through the trays,becoming rich in catalyst. This enriched material is pumped out of the bottom of the absorber andinto the stripping column. The stripper separates the catalyst and absorbent as the vaporized cat-alyst moves up the column and out to the reactor system. The lean absorbent is pumped out ofthe bottom of the stripper and into the top of the absorption column.The physical properties of theabsorbent allow it to gently tug the catalysts out of the absorber and then release them whenexposed to higher temperatures in the stripper. Catalyst-free waste gases flow out the top of theabsorber and into the vapor recovery system.

The purpose of the absorption and stripping model is to illustrate to apprentice technicians howdistillation columns can be used to separate a specific component and feed it back into the sys-tem. The principles of distillation can be used in a varaiety of ways. The basic components of theabsorption and stripping model include:

• Distillation column used for absorption• Distillation column used for stripping• Two heat exchangers for cooling• Two heat exchangers for heating• Stirred reactor• Four pumps• Modern process control instrumentation• Vapor recovery system and flare• Separator

376


17.13 Distillation Model

Distillation is a method used to separate chemical substances in a boiling mixture based uponindividual variations in the volatilities of those substances. Distillation is used to separate crude oilinto various fractions; separate salt from water; separate oxygen, nitrogen, and argon from air; anddistill beverages for higher alcohol content. A variety of distillation models can be used with thevarious troubleshooting methods. A distillation system includes a well-defined feed system, anoverhead system, a bottom system, and a column system overview. Plate columns and packedcolumns offer a different variety of process troubleshooting scenarios. In Figure 17–13, a binarymixture is heated and sent to an eight-tray distillation column.The feed system uses a flow control,

17.13 Distillation Model

377

Fi

Fi

Fi

Fi

Fi

Fi

PIC

PIC

PE

Ti

Ti

Ti Ti

Ti

Ti

TIC

TIC

Vapor Recovery System

Vapor Recovery System

PT

FIC

FIC

LIC

LIC

LE

I/P

AT

AT

TE

To Separator

To Separator

Vaporized Catalyst

Abs

orbe

nt

Absorbent

Absorbent Lean with Catalyst

Chill Water

CWS CWR

DPT

DPT

Rich with Catalyst

Catalyst & Fuel Gas

Steam

Reboiler

1. Product 2. Waste 3. Catalyst

Hot Oil

Figure 17–12 Absorption and Stripping Model

378


PE

PT

Column

Product Tank

Product Tank

Condenser

Drum

I

I

P

P

FE FT

FE

FT

TE

TE

TT

LE LT

I

I

P

P

100%

SP PV OP%

525 GPM

525 GPM

FIC

FIC

LIC

TIC

158.7ºF SP PV OP%

SP PV OP%

50%

50%

0%

SP PV OP%

100psig

100%

100%

100%

SP PV OP%

Pi

Pi

DPT

Pi

Pi

Fi Ti

Fi

Pi

From CTW

To CTW

142.8 GPM

PIC

To Flare

To Reactor

10.4 CuFt/min

AT Fi

Ti

60.5 gpm

60.5 gpm

0 gpm

128 ºF

2.4 psi

TE

AT

TE

TE

TE

190.2ºF

200ºF

210ºF

222ºF

170.2ºF

180ºF

180.5ºF

Feed In Temp @ 225GPM

Feed Tray #1

Tray #2

Tray #3

Tray #4

Tray #5

Tray #6

Hat Tray

From Kettle Reboiler

To Kettle Reboiler

LG

98.5%

61%

125ºF

45 psig

50 psig

160 psig

50%

50%

SP PV OP%

50%

50%

SP PV OP%

I P

LT LE LIC

Fi

I P

LT LE LIC

Fi

AUTO

TV AV

TV AV

TV AV

TV AV

TV AV

TV AV

TV AV

TV AV

TV AV

TV AV

TV AV

TV AV

TV AV

AV

AV TV AV

TV AV TV

AV

TV AV

TV AV

TV AV

TV AV

TV AV

105 psig TV

105 psig TV AV

223ºF TV

FC

FC FC

FC

Figure 17–13 Distillation Model

temperature control, and primary-variable indicators. Changes can be made to one or more ofthese variables and observations recorded by individual learners. Software from a number ofcompanies supports these changes and responses.

Sample problems on the feed system can be paper-based or electronic. These same problemscan be plugged into the overhead and bottom systems. In a distillation system, the followingvariables are directly related to each other:

• Pressure and boiling point• Temperature and pressure• Composition changes in feed to column• Level in accumulator, reboiler, tanks, tray flooding• Flow rate• Time

17.14 Separation Model

A separator is a device that is designed to separate two liquids from each other through densitydifferences; typically, a solvent is introduced that will dissolve one of the components in the mix-ture and thereby enhance the separation process. A separator has a shell, a weir, a vapor cavity,a feed inlet, an extract pump, and a raffinate pump.

One of the problems most frequently encountered in chemical process operations is that of sepa-rating two materials from a mixture or a solution. Distillation is perhaps the most frequently usedmethod of making such a separation, but extraction is also useful. In an extraction process, twomaterials in a mixture are separated by introducing a third material that will dissolve one of the twomaterials but not the other. In liquid-liquid extraction, all four materials are liquids, and the mixtureis separated by allowing them to layer out by weight or density. Many chemicals are sensitive toheat and will degrade or decompose if raised to a temperature high enough for distillation. In thesecases, extraction, which can usually be carried out at normal temperatures, is a practical alterna-tive. Because many relatively inexpensive solvents are available, and because the equipmentrequired for an extraction operation is relatively simple, economic considerations often favor liquid-liquid extraction.

There are basically three steps in the liquid-liquid extraction process: (1) contact the solventwith the feed solution; (2) separate the raffinate from the extract; (3) separate the solvent fromthe solute. Step 3, recovery of the solvent and solute, is left to be done by some other process,such as distillation. In liquid-liquid extraction, the feed solution, containing the solute (thematerial that will be dissolved), is fed to the lower portion of the extraction column. The solvent(the material that dissolves the solute) is added near the top. Because of density differences,the lighter feed solution tends to rise to the top while the heavier solvent sinks to the bottom.As the two streams mix, the solvent dissolves the solute. Thus, the solute, which was originallyrising with the feed solution, actually reverses its direction of flow and goes out with the solventthrough the bottom of the column. This new solution, consisting of solvent and solute, iscalled the extract. The other chemical in the feed stream, now free of the solute, goes out thetop as the raffinate. The raffinate and extract streams are not soluble in each other and willlayer out.

17.14 Separation Model

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The solvent must be able to dissolve the solute, but it should not dissolve the raffinate or contam-inate it. It also must be insoluble, so that it will layer out.The density of the solvent should vary suf-ficiently from the density of the raffinate so that they can layer out by the effects of gravity. Thesolvent must be a substance that can be separated from the solute. It should be inexpensive andreadily available, and it should not be hazardous or corrosive.

Common separation problems include:• Feed composition changes• Unreacted feed• Loss of cooling water• Loss of level control• Instrument problems• Loss of pressure control• Equipment failures—example pump

380


65 psig

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104.5 gpm

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107 psig

89.5 gpm

89.5 gpm

67 psig

65 psig

8% 99.9%

110 psig

FC

FC

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Figure 17–14 Separator System Model

Figure 17–14 shows the basic flow path and equipment and instruments associated with theseparator system.

17.15 Multivariable Model

The purpose of the multiple-variable model is to provide an apprentice technician with a compre-hensive view of the large scope of operations he or she will be exposed to in the chemical pro-cessing industry. When all of the equipment pieces are combined into a full-scale plant, it is easierto see how each system operates and the potential problems that troubleshooters will encounter.Nine of the troubleshooting models have been combined to make the multivariable model shownin Figure 17–15.

Summary

The ability to clearly see the process and sequentially break down, identify, and resolve processproblems signals that a technician has reached one of the highest levels of learning. Experienceis a proven teacher, although new computer technology can be used to quickly and methodicallytrack down process problems. A single problem can have a cascading effect on all surroundingequipment and instrumentation.

Troubleshooting models include the reaction model, the absorption and stripping model, the sep-aration model, and the distillation model. These models constitute the equipment and systemspresently being used for instruction in community colleges and universities. These models arecompletely outfitted with alarms, analyzers, interlocks, permissives, video trends, recorders, andcontrol instrumentation. Process problems can be simulated using these models.

A college curriculum includes the use of advanced computer system software that closely simu-lates console operations. Some college training systems have modern control instrumentationmounted on operational pilot units. Students using these types of systems receive true hands-onexperience.

The four models used to teach process troubleshooting are the distillation model, the reaction andseparation model, the absorption and stripping model, and the combination model. Each modelhas a complete set of process control instrumentation and equipment arrangements.Various trou-bleshooting methodologies are applied to these four models. A complete range of troubleshootingscenarios has been developed and is typically included with these models.

Troubleshooting methods vary depending on the individual educational faculty, consultants, andindustry. These methods include educational, instrumental, experiential, and scientific.

The troubleshooting process requires a wide array of skills and techniques. The primary goal isto control variables such as temperature, pressure, flow, level, and analytical. With modern control instrumentation, such as indicators, alarms, transmitters, controllers, control valves, trans-ducers, analyzers, interlocks, and so on, it is possible to control large, complex processes from asingle room.

Summary

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Hot OilTank

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65 psig

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104.5 gpm

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Figure 17–15 Multivariable Model

Data collection, organization, and analysis are another part of troubleshooting process problems.Data analysis utilizes a variety of quality techniques to put all of the parts in place. Process flowdiagrams are used to identify the primary flow path and control instrumentation being used in theprocess. Checksheets are used to collect large amounts of quantitative data that can be organ-ized into graphics or trends to plot process variation or changes.

Summary

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Chapter 17 Review Questions1. List the various troubleshooting models.

2. Compare and contrast troubleshooting methods with troubleshooting models.

3. Describe the term process troubleshooting.

4. Explain how control loops are used in process troubleshooting.

5. Compare and contrast primary and secondary problems on an operating system.

6. How are checklists used to troubleshoot problems?

7. List the various instruments used in troubleshooting.

8. In Figure 17–11, what would happen if the heat was lost?

9. Draw a pressure and level control chart.

10. In Figure 17–2, what would happen if the pressure increased 50 psi?

11. In Figure 17–1, what happens when the steam flow increases?

Self-Directed Job SearchAfter studying this chapter, the student will be able to:

• Explain how to conduct a successful job search.• Write an effective cover letter.• Write an effective process technology resume.• Obtain job lists from local chambers of commerce.• Describe the kinds of preemployment tests that are given to job applicants.• Compare the benefits of work experience and education.

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Chapter 18 ● Self-Directed Job Search

Key TermsEducational credentials—job qualifications earned through school study; include a one-yearcertificate or a two-year AAS degree. Certificates may be level one or level two.

Job lists—information about potential employers; contain contact name, address, telephonenumber, and size of company. They can be obtained from the local chamber of commerce(a small fee may apply).

Job search—requires four to six months, a good resume and cover letter, a certificate ordegree, good investigative skills (to identify who is hiring and who to contact), knowledge ofapplication methods, interest cards, tests, and so on. Job searches are very difficult and requireserious dedication, time, and a “thick skin.”

Preemployment tests—examinations administered by potential employers to determineapplicants’ job qualifications and readiness; examples include the Bennett Mechanical Comprehen-sion Test (BMCT) by George K. Bennett (S & T version); the Richardson, Bellows, Henry & Company“Test of Chemical Comprehension” (S & T version, 1970); and the California Math Test. Types includereading comprehension, accuracy checking, block counting, and tests developed in-house.

Resume—a one-page document designed to sum up a job applicant’s skills, work history,hobbies, and education.

18.1 The Job Search

Understanding the job market is very important in conducting a successful job search. Althoughstatistics indicate that a large number of process technician positions will become available over thenext 10 years, the chemical processing industry is very cyclical in nature. Employment opportunitiesmay surface only once a year. Each company has different hiring needs and different mechanisms forgranting interviews. It is the responsibility of each job applicant to become familiar with the hiring prac-tices of the companies in the area or in which he or she is interested. A list of companies that arepotential employers can be obtained at the chamber of commerce (sometimes a small fee is charged).A telephone call to the company can also provide an applicant with invaluable information.

As a new job applicant, you will be competing against a large number of people for a select few jobs.Only a small fraction of process technician job seekers are truly qualified to work in the chemical pro-cessing industry. A job applicant whose educational credentials include a one-year certificate inprocess technology is much better prepared than applicants without job-specific education. It hasbeen statistically proven that graduates of process technology programs complete mandatory train-ing and job post-training more quickly than non-graduates, and have a very low dropout rate afterstarting a new job.The truth is that it is very difficult to compete with new graduates—if they can findtheir way through the mass of unqualified candidates and secure interviews.

Job Market Facts:• Job lists can be picked up at local chambers of commerce.• Hiring practices are cyclical.

• A job search can take four to six months.• The majority of process technician job applicants are not qualified for the job.• Each company has its own hiring practices and procedures for prospective

employees.• Preemployment testing procedures vary by company.• The process technician degree is valuable.• Finding a job is your responsibility.• Networking yields more job opportunities.• Newspaper ads have poor placement rates.• A good resume and cover letter are important.

Now that you have enrolled in the process technology degree program, there are a number ofthings you should know so you can position yourself as the top candidate. To be a top candidate,you will need to be better at searching for a job than other people. High grade-point averages(GPAs) and test scores do not indicate how successful you will be in a job search. The truth is,most people are not very good at looking for work. A number of critical elements determine jobsearch success:

• Job searching is your responsibility—do not believe that someone else will find you a job.

• Develop a job search plan.• Narrow your search—Houston area, Salt Lake City, near your home.• Interview—this is a numbers game. The more interviews, the better your chances.• Learn to network—75% of all jobs come from networking.• Do not rely heavily on newspaper ads; the placement rate from these widely

disseminated ads is poor.• Use placement agencies—Certified Personnel; Manpower, Inc.; Skillmaster;

Kelly Scientific Services; Allstates Personnel; Staffing Professionals;college job placement services; and so on.

• Become a private investigator:– contact employers– call hot lines– write sales letters– visit human resources (HR) departments– find out hiring procedures

• Write a good resume.• Develop good interview skills:

– research the company– make a positive first impression: solid handshake, appropriate dress– state your strengths; develop rapport (“chemistry”) with interviewers– practice answering hard questions

• Follow up.

Resume and Cover LetterA successful job search requires a cover letter and a resume. The resume is a summary of yourlife experiences, presented in a positive, concise, and job-relevant manner. A variety of formats are

18.1 The Job Search

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available (the Internet has a number of good resources for resumes); select a style based on yourindividual preference. Elements of a resume include:

• Your name• Address• Telephone number(s)• E-mail address• PTEC education• Work experience• Reference(s)

Figure 18–1 shows a sample resume.

It is important for you to write your own resume. Do not have a friend or relative write it for you;they may include things about you that would be difficult to explain in an interview.

Complete your resume before you write the cover letter. A good cover letter should introduce youto the company, highlight important points of your resume, and make an interviewer want to talkto you. Elements of a cover letter include:

• Your address• Date• Name and address of the person you are contacting• Greeting• Paragraph 1—a brief explanation of why you are writing and how you found out

about the company• Paragraphs 2–3—a description of how your education and skills would benefit

the organization• Last paragraph—request for a reply; tell the reader how to reach you• Complimentary closing

Figure 18–2 shows an example of a cover letter.

The Selection Process and InterviewsDuring the selection process, a job placement officer sees literally hundreds of resumes. Recruit-ing is an important feature of good business, and most companies take it very seriously. Job in-terviewers carefully screen for the best applicants. In a job search, aggressive, professionalmarketing will give you an edge over competing applicants. The next step can be summed up as:“It’s how you package the product.” A well-written, clean resume and cover letter can go a long waytoward getting you an interview.

During the selection process, resumes and job applications are typically separated into threestacks: AAS degree—process technology, one-year certificate, and uneducated. A company mayuse a preemployment test to select resumes to investigate further. Process experience is anotherimportant variable used to determine second-phase recruiting or who will get an interview.

Companies select employees based upon a wide array of needs. Attrition rates and new plantexpansions create opportunities for process technicians. Companies will attempt to hire the best

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18.1 The Job Search

389

GLENDA RAMIREZ

75 East Payton St.Houston, TX 77409

Home 555-456-1234Cell 936-776-0123

[email protected]

OBJECTIVE To obtain an entry-level position as a process technician.

EDUCATION In 2009 I graduated from technical college with an Associate ofApplied Science (AAS) degree in Process Technology. Mycourse of studies included the operation and maintenance of afull-scale pilot plant, console operation, bench-top operation,process equipment and systems instrumentation, chemistry,math, and physics. Additional topics of study included safety,quality control, troubleshooting, and the academic core.

EMPLOYMENT06/07–Present

REFERENCES

True Value Hardware, Baytown, TexasSupervisor: Bill Johnson, 555-425-1234Performed general maintenance, stocking, sales.

My Favorite Instructor—Process TechnologyProcess Technical CollegeP.O. Box 848, Baytown, TX 77522-0818

Figure 18–1 Resume Example

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75 East Payton St.Houston, TX 77409June 5, 2009

Ms. S. JohnsonHuman Resource ManagerTexas Refinery and Chemical Company Inc.Baytown, TX 77522

Dear Ms. Johnson:

I am writing in response to your classified ad for a process technician placed in theBaytown Sun and Houston Chronicle on June 4. Enclosed you will find my resume, whichdescribes my educational background and work experience.

On May 15, 2009, I graduated with an Associate of Applied Science degree in ProcessTechnology from Process Technical College. As my enclosed resume indicates, I havetaken courses that have prepared me to take an entry-level position as a processtechnician at your company.

I look forward to meeting with you for an interview. If you have any additional questions,please call 555-456-1234 after 3:00 p.m., or my cell 936-776-0123. I can also becontacted at [email protected].

Sincerely,

Glenda Ramirez

Figure 18–2 Cover Letter Example

possible candidate based on company needs, equal employment opportunity (EEO) require-ments, and personal relationships.

Typical interview questions asked by employers include:• Tell us about yourself. Why should we hire you?• Why do you want to leave your present position?• Why did you leave your last job?• Tell me what you have learned in your college classes.• Tell me about the different types of pumps you have studied.• What is distillation? What is reflux and what is its purpose?• List the elements of a control loop.• Do you have any hands-on experience?• Tell me how to put a distillation system online.• What do you know about our company?• What are your personal goals in this job for the next year? The next five years?

The next ten years?• How do you handle stress?• If you were asked to perform an unsafe act by your supervisor, how would you respond?• Why did you choose to be a process technician?• Do you have plans to continue your education?

Questions asked by job applicants might include:• Can you tell me about your safety program?• What specific responsibilities of the position do you consider the most important?• How are process technicians evaluated at your company?• What would you expect me to accomplish during my first six months? The first year?

Two years?• What long- and short-term problems will I face as a new technician at your company?

The following are some suggestions for job searching by process technology students:• Get a one-year certificate in process technology.• Get a two-year degree in process technology.• Prepare for preemployment tests, and sign up for placement agency tests.• Improve your skills in math, reading comprehension, and communications.• Develop a network (friends, instructors); get references; gather documents; prepare

for interviews; research companies; develop a job search plan.• Prepare a resume, target companies you want to work for, mail out resumes, follow

up on job leads, get jobline numbers.• Dress appropriately—jeans, long-sleeved shirt, work boots, little makeup,

toned-down jewelry.• Be accessible—allocate time; get an answering machine; check your e-mail frequently.• Sign up with your state’s workforce commission and placement agencies.• Identify your strengths and weaknesses.• Don’t get discouraged; find healthy ways to deal with stress.• Go to chambers of commerce and get job lists.• Go to companies and develop relationships.• Check out www.twc.state.us (process Internet site for Texas).• Improve your appearance.

18.1 The Job Search

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www.twc.state.us

18.2 Preemployment Testing

At present, a variety of preemployment tests are given to job applicants.The most common types ofpreemployment tests include mechanical aptitude, chemical comprehension, reading comprehen-sion, basic math, psychological, and block-counting exams. Some companies spend thousands ofdollars developing their own tests; others use standardized exams. Mechanical aptitude tests are ad-ministered frequently to individuals wishing to work in the chemical processing industry. Mechanicalaptitude reveals your ability to predict which way an object will move when influenced by an outsideset of forces. The most common form is the Bennett Mechanical Comprehension Test (BMCT)by George K. Bennett. The BMCT uses an S-and-T (science and technology) format that includes68 questions. Another mechanical aptitude test that can be purchased at local bookstores is theARCO book on mechanical aptitude and spatial relationships.There are a number of good texts thatwill help new technicians improve their ability to work out mechanical aptitude problems.

In 1970, Richardson, Bellows, Henry & Company developed the “Test of Chemical Comprehension.”This test comes in a 50-question, S-and-T format. Questions on the test were developed from infor-mation that should be learned in a high school science class.Most preemployment tests have a mathsection that covers addition, subtraction, multiplication, division of fractions and whole numbers,decimals, averaging, percentages, and low-level algebra. Block-counting tests ask the job applicantto look at a three-dimensional drawing and identify the total number of blocks. Because some ofthe blocks are hidden, this test can be tricky; carelessly rushing through this section of the test isa mistake. The block-counting test is designed to screen for observational accuracy. Readingcomprehension is a common testing practice that screens for how well a technician can read a para-graph or two and then answer or respond to specific instructions or questions. People who readand comprehend quickly should not be concerned about this type of testing. If you like to readinstructions carefully before you respond, you will need to develop a system that increases yourspeed, as all of these tests are timed.

18.3 Work Experience

Industrial employers have traditionally valued prospective employees who have experience in in-dustry. Some companies require five years of experience before they will even initiate the inter-view process. Industrial experience provides a track record of a person’s stability, ability to workrotating shifts, and exposure to industrial processes and the environment.

One might argue that experience or exposure to all industrial processes is impossible to obtain,since more than 40 petrochemical processes and 19 refinery processes can be identified (and thisdoes not include the gas processes). The only common thread between these facilities is theequipment and technology used, although it appears in different arrangements. A prospective em-ployee with strong science and math backgrounds, good mechanical aptitude and troubleshoot-ing skills, and a process technology degree provides prospective employers with an informedtrainee who is well prepared to start site-specific training.

With the availability of such education, experience does not carry the weight that it used to. Since1989, the government and industrial manufacturers have been raising the bar for process techni-cians. Displaced process operators are being required to go back to school and obtain a certificate

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or degree before they can return to their occupation. This added level of education is designed toprotect the process technician, community, and industrial manufacturers from inability to handlerapid advances in technology. Experienced technicians have a number of negative issues and con-cerns to address, including:

• Why did you leave your last job?– Bad habits?– Trained incorrectly?

• Do you have a two-year degree in process technology?• What industrial processes have you been exposed to?• Did you complete a Department of Labor-approved apprentice training program?

Do not let a lack of experience discourage you. The bottom line in job seeking is to get a good ed-ucation, develop your foundational skills, and “sell yourself” with a good resume, cover letter, andinterview responses.

Summary

A successful job search requires four to six months, a good resume and cover letter, a certificateor degree, and good investigative skills to identify who is hiring, who to contact, the applicationmethod, and so on. Job searches are very difficult and require serious dedication, time, andpersistence.

A variety of preemployment tests are given to job applicants in the chemical processing industry,including the Bennett Mechanical Comprehension Test and the “Test of Chemical Comprehension.”Tests may focus on mechanical aptitude, reading comprehension, and/or basic math skills.

Industrial work experience provides a track record of a person’s stability, ability to work rotat-ing shifts, and exposure to industrial processes and the environment. Experience is not asimportant as it used to be, however, now that more than 40 petrochemical processes and 19 refinery processes are in operation. A prospective employee with strong science and mathbackgrounds, good mechanical aptitude, troubleshooting skills, and a process technologydegree provides prospective employers with an informed trainee who is well prepared to startsite-specific training.

Summary

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Chapter 18 Review Questions1. List the key elements of a resume.

2. Write a resume.

3. List the key elements of a cover letter.

4. Write a cover letter.

5. Tell us about yourself. Why should we hire you?

6. Why do you want to leave your present position?

7. Why did you leave your last job?

8. Tell me what you have learned at Process Technical College.

9. Tell me about the different types of pumps you have studied.

10. What is distillation? What is reflux and what is its purpose?

11. List the elements of a control loop.

12. Do you have any hands-on experience?

13. Tell me how to put a distillation system online.

14. How do you find information about a company?

15. What are your personal goals in this job for the next year? The next five years? The nextten years?

16. How do you handle stress?

17. If you were asked to perform an unsafe act by your supervisor, how would you respond?

18. Why did you choose to be a process technician?

19. Do you have plans to continue your education?

20. Select an ad from the paper and apply for a process job.

Applied GeneralChemistry TwoAfter studying this chapter, the student will be able to:

• Describe the basic steps of the scientific method.• Describe the concept of a mole.• Solve simple exponential notation problems.• Understand the nature of elements and compounds.• Read and use the periodic table.• Describe the principles associated with electron configuration.• Recognize and interpret the formulas for organic chemicals.• Balance simple chemical equations.• Describe the principles of distillation.• Solve simple problems using Dalton’s law of partial pressures.• Describe aromatic hydrocarbons.• Identify the basic concepts associated with chemical bonding.• Describe alkanes, alkenes, alkynes, and cycloalkanes.• Describe the basic characteristics of an alcohol.

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Chapter 19 ● Applied General Chemistry Two

Key TermsAlkane group—family of hydrocarbons that are composed of carbon and hydrogen heldtogether by single covalent bonds.

Benzene—the most common aromatic hydrocarbon. The benzene molecule has six carbonatoms connected in a ring. Each carbon atom has four bonding sites available; in benzene, threeare used and one is free. The three bonds are covalent; the fourth can be shared by all six car-bon atoms. This creates a donut-shaped cloud or aromatic ring. Reactions with benzene aresubstitution and not addition.

Covalent bonding—the mechanism of electron sharing that holds atoms together to formmolecules. In a covalent bond, atoms share a pair of electrons.

Cycloalkane family—group of hydrocarbons characterized by the presence of a ring or cycleof carbons from three methylene groups located on the apex of the equilateral triangle.

Dalton’s law of partial pressures—states that the total pressure of a gas mixture is the sumof the pressures of the individual gases (their partial pressures); Ptotal � P1 � P2 � P3.

Distillation—a process used to separate the components in a mixture by their volatilities in aboiling liquid mixture.

Dmitri Mendeleev—(1834–1907); a Russian professor of chemistry who devised the firstperiodic table of elements.

Exponential (scientific) notation—a number system based on powers of 10 (exponents),designed to make it easier to work with very large numbers.

Ionic bonding—magnetic-type bonds. In ionic bonding, one or more electrons transfer fromone or more atoms to another, creating a positive ion and negative ion that attract and holdeach other. These bonds are extremely strong.

Mole—the molecular formula weight of any substance expressed in grams.

Organic chemistry—the study of compounds that contain carbon.

Saturated hydrocarbon—contains the maximum number of hydrogen atoms and contains sin-gle covalent bonds. An unsaturated hydrocarbon can still accept an additional hydrogen atom.

Science—a way of knowing and understanding the universe and the world we live in. The Latinword for science is scire, which means “to know.”

Scientific method—the systematic process or framework by which science operates.

19.1 Fundamentals of Chemistry

Science is a way of knowing and understanding the universe and the world we live in. The Latinword for science is scire, which means “to know.” Science operates by asking questions, observ-ing, analyzing observations, and communicating observations. This type of procedure raises anever-ending supply of questions. Scientific inquiry uses theories and hypotheses to explain

phenomena. A theory is best described as a firmly grounded interpretation of confirmed observa-tions. A hypotheses is a tentative explanation of a small set of observations. Process techniciansspend a great amount of time making observations and collecting, organizing, and analyzing thedata from those observations.

As active observers and participants in operating a wide variety of chemical processes, techni-cians need to have a good understanding of science and the scientific method. The scientificmethod is the process or framework by which and within which science operates. Collectively, thismethod of learning is very powerful. Key steps in the scientific method include: using a systematic,fact-based approach; asking questions; observing; analyzing observations; and communicatingobservations.

Most of the manufacturing processes in the world use or require a chemical reaction. Plants areset up to provide the conditions that are most favorable for the desired reaction(s). However, to ini-tiate these processes correctly, a certain amount of starting materials (reactants) is needed to be-gin a chemical reaction.These amounts vary depending on the substances used and the reactiondesired, but the amounts must be both sufficient and correct. Thus, we need to know formulaweights. We can calculate this by simply adding up the molecular weights of each element in acompound. For example, the formula weight of urea, (NH2)2CO, is 60 AMU:

N (nitrogen) � 14 � 2 � 28

H (hydrogen) � 1 � 4 � 4

C (carbon) � 12 � 1 � 12

O (oxygen) � 16 � 1 � 16

60 AMU

The MoleThe mole is often referred to as a chemist’s unit of quantity. Counting atoms is a difficult process andbeyond the scope of most calculators, but measuring the mass of a sample is easy when we can re-late the number of atoms in a sample to its mass.This is the unique purpose of the mole. A mole ofany substance is its molecular formula weight expressed in grams. Avogadro’s number is a univer-sal constant that states the number of molecules in a mole: N0 � 6.023 � 1023 molecules/mole. Onemole (abbreviated mol) of any element (chemical compound) has the same number of chemical par-ticles as one mole of another element (chemical compound). In other words, 1 mole of any com-pound contains 6.02 � 1023 molecules. Review the following problem using the mole concept.

EXAMPLEA single aspirin tablet contains 0.36 g aspirin. The molecular formula of aspirin is C9H8O4. Identifyhow many aspirin molecules a single tablet contains.

Step 1 The formula weight of aspirin is:C (carbon) � 12 � 9 � 108H (hydrogen) � 1 � 8 � 8O (oxygen) � 16 � 4 � 64

180 AMU


397

Step 2 0.36 g aspirin � 1 mole aspirin180 g aspirin

� 0.0020 mole aspirin or 2.0 � 10�3 mol aspirin

Note: 1 mole of any compound contains 6.02 � 1023 molecules.

Step 3 2.0 � 10�3 mole (6.02 � 1023 molecules) � 1.2 � 1021 moleculesmole

Answer: 1.2 � 1021 molecules of aspirin (C9H8O4).

Exponential NotationIn chemistry and physics, it is often necessary to work with very large numbers. An easy way tohandle these large numbers is called exponential notation, a system based on the powers of 10.Exponential notation is also referred to as scientific notation. For example, 57,500 can be ex-pressed as 5.75 � 104. We generate the exponential notation by moving the decimal point fourplaces to the left and inserting the multiplier of the correct power of 10: 57,500 � 5.75 � 104. Wecan do the same thing with a number like 0.0000575 by moving the decimal point five places tothe right to express it as 5.75 � 10�5.

When it is necessary to add, subtract, divide, and multiply numbers in exponential notation,there are a number of rules that must be followed. To add or subtract, the exponents must bethe same. For example:

4.5 � 10�3

� 8.2 � 10�3

12.7 � 10�3 or 0.0127 � 1.27 � 10�2

If the exponents are different, a correction must be made to one of the variables. For example, to add 5.95 � 10�2 and 1.8 � 10�3, we would have to adjust the expression as follows:

5.95 � 10�2

� 0.18 � 10�2

6.13 � 10�2

The same principle holds true when we subtract exponents. For example, to subtract 5.21 � 104

from 1.77 � 105, the expression would be adjusted to:

1.77 � 105

.521 � 105

1.25 � 105

398


When it is necessary to multiply numbers in exponential notation, we multiply the numerical coef-ficients and algebraically add the exponents. For example, to multiply 5.5 � 105 by 2.25 � 109, wewould use the following expression:

5.5 � 2.25 � 12.375

105 � 109 � 105�9 � 1014

Answer: 12.4 � 1014 � 1.24 � 1015

When it is necessary to divide numbers in exponential notation, we divide the numerical coefficientsand algebraically subtract the exponents. For example:

9.5 � 108

3.1 � 1010

9.5 � 3.1 � 3.06

108 � 1010 � 108�10 � 10�2

Answer: 3.06 � 10�2

Examples of Exponential Notation

0.001 � 10�3

0.01 � 10�2

0.1 � 10�1

10 � 101

100 � 102

1000 � 103

Elements and CompoundsElements are composed of identical atoms; they are the fundamental substances of chemistry andthe process industry. Elements cannot be converted into other elements. Today we recognize 116different elements. Some of these elements include carbon and hydrogen, which are the primarybuilding blocks of materials for the chemical and refining industry. Process technicians also com-monly use other elements, such as oxygen, nitrogen, sodium, magnesium, potassium, chlorine,helium, iron, copper, titanium, gold, platinum, mercury, aluminum, and argon.

Compounds are composed of two or more elements in well-defined ratios. Sugar is a compoundformed by three elements—carbon, hydrogen, and oxygen—in specific ratios. Sodium chloride(table salt) is a compound formed from the combination of two elements, chlorine and sodium,in specific ratios. Other common compounds include water (H2O), sodium (23 AMU) chloride(35.5 AMU), and hydrogen peroxide.


399

19.2 The Periodic Table and Chemical Bonding

Three factors affect the properties of an atom or ion: atomic number, mass number, and electronconfiguration. Process technicians are primarily concerned with the electron configuration andthe valence shell. The outermost shell in an atom is referred to as the valence shell. The atoms ofelements have different arrangements and they tend to react in an effort to fill the valence shell.The electrons in the valence shell are referred to as valence electrons.

Periodic TableDmitri Mendeleev, a popular Russian professor of chemistry who lived from 1834 to 1907, de-vised the first periodic table of elements. During his studies, Mendeleev recognized repetitions inthe properties of elements; that is, properties and similarities that repeated over and over again.This recurrence is referred to as periodicity or periodic.

The periodic table is organized in sequence of increasing atomic number rather than by atomicweight (Figure 19–1).The elements tend to fall into rows so that elements in the same vertical col-umn or group have similar properties. Boiling points and melting points tend to increase as wemove down a column. For example, the elements in column 18 are gases at room temperature andtend not to react and form compounds; only a few exceptions can be found.

After some thought, Mendeleev numbered the columns with Roman numerals, some with the let-ter “A” and some with the letter “B.” This system was used virtually unchanged until quite recently,when minor variation between U.S. and European chemists (A/B variation) forced the internationalchemistry organization to recommend a column numbering system from 1–18, moving from left toright. In columns 1, 2, and 13–18, a number of elements extend above the rest. These elementsare referred to as representative elements. The elements found in columns 3–12 are classified astransition elements. At the bottom of the periodic table are two rows that appear to be separatedfrom the main body of the table. This is for convenience only. Elements 58–71 and 90–103 arecalled inner transition elements and actually fit between columns 3 and 4.

The elements on the periodic table can be classified as metals, nonmetals, metalloids, or noblegases. Metals tend to be shiny and have atoms that give up electrons. Metals are malleable andtend to be excellent conductors of heat and electricity. By nature, nonmetals do not conduct elec-tricity and have atoms that do not naturally give up electrons; however, they do tend to accept elec-trons. The metalloid elements are located along the heavy black stair-step line on the right-handside of the periodic table. Boron, silicon, germanium, arsenic, antimony, tellurium, polonium, andastatine are classified as metalloids.

Helium, neon, argon, krypton, xenon, and radon are classified as inert or noble gases. These sixelements have unique properties that are different from those of the other nonmetals. These inertor noble gases refuse to accept or give electrons.The rest of the nonmetals include hydrogen, car-bon, nitrogen, oxygen, fluorine, phosphorus, sulfur, chlorine, selenium, bromine, and iodine.These11 elements are critical in the study of organic chemistry.

400


19.2 The Periodic Table and Chemical Bonding

401

H

H - gas

Li Be

Na

Na - solid

Mg

K Ca

Rb Sr

Cs Ba

Fr

Fr - liquid

Ra

Sc

Y

La

Ac Rf Db Sg Bh Hs Mt Ds Rg

Ti

Zr

Hf

V

Nb

Ta

Cr

Mo

Re

Fe

Ru

Os

Co

Rh

Ir

Ni

Pd

Pt

Cu

Ag

Au

Zn

Cd

Hg

B

W

Mn

Al

Ga

In

Tl

C

Si

Ge

Sn

Pb

N

P

As

Sb

Bi

O

S

Se

Te

Po

F

Cl

Br

I

At

He

Ne

Ar

Kr

Xe

Rn

Tc

1 1.0079

HYDROGEN

3 46.941 9.0126

LITHIUM BERYLLIUM

11 1222.99 24.30

SODIUM MAGNESIUM

19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36

37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54

55 56 57 72

87 88 89 104 105 106 107 108 109 110 111 116115112 113 114

73 74 75 76 77 78 79 80 81 82 83 84 85 86

2

5 6 7 8 9 10

13 14 15 16 17 18

10.81 12.01 14.006 15.99 18.99

26.98 28.08 30.97 32.06 35.45

20.18

4.002

39.94

39.09 40.08 44.95 47.9 50.94 51.99 54.93 55.84

POTASSIUM

RUBIDIUM

CESIUM

FRANCIUM

CALCIUM

STRONTIUM

BARLUM

RADIUM

87.62

137.33

226

SCANDIUM

YITRIUM

LANTHANUM

ACTINIUM Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium

88.9

138.9

227 262261 263 263 266265 271 272

TITANIUM

ZIRCONIUM

HAFNIUM

91.22

178.4

VANADIUM

NIOBIUM

TANTALUM

92.9

180.9

CHROMIUM

MOLYBDENUM

TUNGSTEN

95.9

183

MANGANESE

TECHNETIUM

RHENIUM

98

186

IRON

RUTHENIUM

OSMIUM

101

190

58.93

COBALT

RHODIUM

IRIDIUM

102.9

192

58.7

NICKEL

PALLADIUM

PLATINUM

106.4

195

63.54

COPPER

SILVER

GOLD

107.8

196.9

65.38

ZINC

CADIUM

MERCURY

112.4

200.6

69.72

GALLIUM

INDIUM

THALLIUM

114.8

204.3

72.59

GERMANIUM

TIN

LEAD

118.6

207

74.92

ARSENIC

ANTIMONY

BISMUTH

121.7

208.9

78.96

SELENIUM

TELLURIUM

POLONIUM

127.6

209

79.90

BROMINE

IODINE

ASTATINE

126.9

210

83.8

KRYPTON

XENON

RADON

131.3

222

ALUMINUM SILICON PHOSPHORUS SULFUR CHLORINE ARGON

BORON CARBON NITROGEN OXYGEN FLUORINE NEON

HELIUM

85.46

132.90

223

THOMAS PERIODIC TABLE OF ELEMENTSGROUP

1A

2A

3B 4B 5B 6B 7B 8B 1B 2B

3A 4A 5A 6A 7A

V111A

Transition Elements

28

112

2

28

288

28

188

28

18188

28

1832188

27

287

28

187

28

18187

28

1832187

26

286

28

188

28

18186

28

1832187

25

285

28

185

28

18185

28

1832185

24

284

28

184

28

18184

28

1832184

23

283

28

183

28

18183

28

1832183

28

182

28

18182

28

1832182

28

181

28

18181

28

1832181

28

162

28

18180

28

1832171

28

152

28

18181

28

1832170

28

142

28

18151

28

1832142

28

132

28

18141

28

1832132

28

131

28

18131

28

1832122

28

102

28

18121

28

1832112

28

18102

28

1832102

2892

28

1892

28

181892

28

18321892

22

28

183292

282

2882

28

1882

28

181882

28

18321882

1

21

281

2881

28

1881

28

181881

28

18321881

Period

1

1

12345678

2

2

3

3

4

4

5

5

6

6

7

7 8 9 10 12

13

11

14 15 1716

18

NobleGases

Inert or

Nonmetals

Discovered-1996 2004 1999 2004 1999

Ce Pr

Th Pa

Nd

U

Pm

Np Pu

Sm Eu

Am

Tb

Bk

Dy

Cf

Ho

Es

Er

Fm

Tm

Md

Gd Yb

No

Lu

LrCm

58 59 60 61 62 63 64 65 66 67 68 69 70 71

90 91 92 93 94 95 96 97 98 99 100 101 102 103

140.115 140.9076 144.24 144.91 150.36 151.965 157.25 158.9253

Cerium

Thorium

Praseodymium

Protactinium

231.03

Neodymium

Uranium

238.03

Promethium

Neptunium

237.05

Samarium

Plutonium

244.66

Europium

Americium

243.06

Gadolinium

Curium

247.07

Terbium

Berkelium

247.07

162.5

Dysprosium

Californium

251.08

164.9303

Holmium

Einsteinium

252.08

167.26

Erbium

Fermium

257.1

168.9342

Thulium

Mendelevium

258.1

173.04 174.967

Ytterbium Lutetium

Nobelium Lawrencium

262.1259.1232.04

Lanthanides

Actinides

Electron Placement1s

2s 2p3s 3p 3d

4s 4p 4d 4f5s 5p 5d 5f

6s 6p 6d7s 7p

8s

Inner Transition Elements

28

18323292

28

183282

28

18323192

28

183182

28

18323092

28

183082

28

18322992

28

182982

28

18322892

28

182882

28

18322792

28

182782

28

18322692

28

182592

28

18322592

28

182582

28

18322582

28

182482

28

18322392

28

182382

28

18322292

28

182282

28

18322192

28

182182

28

18322092

28

182082

28

183218102

Prefixes1. mono2. di3. tri4. tetra5. penta6. hexa7. hepta8. octa9. nona10. deca

Diatomic Elements1. Bromine2. Chlorine3. Fluorine4. Hydrogen5. Iodine6. Nitrogen7. Oxygen

Common PositiveValencesFe 2, 3

Ni 2Cu 1, 2

Zn 2Al 3Ag 1Cd 2

Sn 2, 4Au 1

Hg 1, 2Pb 2, 4

Multivalent Metals (ous) (ic)Iron Fe Ferrum +2 +3Lead Pb Plumbum +2 +4Tin Sn Stannum +2 +4Mercury Hg Mercurum +1 +2Copper Cu Cuprum +1 +2

1s

2s

3d 3d 3d 3d 3d 3d 3d 3d 3d 3d

3s

4f

4d 4d 4d 4d 4d 4d 4d 4d 4d 4d

4s

5f

5d 5d 5d 5d 5d 5d 5d 5d 5d 5d

5s5s

7s7s 6d 6d 6d 6d 6d 6d 6d 6d 6d

6s6s

2p2p 2p

3p 3p3p 3p

4p 4p 4p 4p 4p 4p

5p5p5p5p 5p 5p

6p6p6p6p 6p 6p

1s

C6 12.011

CARBON

AtomicNumber

Symbol

electrons inshells

ElectronPlacement

Atomic Weight

Element

24

2p

Boiling Point(K)Melting Point (K)Density @ 300K (g/cm3)

447041002.62

20.314.09

1615454.53

274515601.9

1156371.97

1032336.86

9613131.53

9443021.9

950300

13639221.74

175711121.55

165010412.6

217110023.5

18099735

3473132310.07

373011936.7

361117994.5

310418123

356219434.5

468221256.49

4876250013.1

368221755.8

5017274 08.55

5731328716.6

294521307.19

4912289010.2

5828368019.3

233515177.43

4538247311.5

5869345321

5285330022.4

4423252312.2

313518097.86 3201

17688.9

3970223612.4

4701271622.5

318717268.9

3237182512

4100204521.4

3130133819.2

2436123410.5

283613588.25

11806937.14

10405948.65

63023413.53

174657711.85

23464307.31

24783035.91

27939332.7

427523002.34

447041002.62

354016852.33

310712105.32

28765057.3

202360111.4

77.3563.141.25

5503171.82

87610815.72

18609046.68

18375459.8

90.1850.351.43

718388.42.07

9584944.8

12617236.24

12355279.4

8553.51.7

2391723.17

3322663.12

4583874.92

610575

4.2.95.1787

27.124.6.90

87.383.81.784

119.8115.783.74

165161.45.89

2112029.91

369910716.78

5061202811.7

378512046.77

--------15.4

334112897.0

4407140518.9

378512046.5

----91020.4

206413457.54

350391319.8

187010905.26

2880126813.6

353915857.89

----134013.5

349616308.27

____________

____________

____________

____________

____________

____________

283516828.54

____900____

296817438.8

313617959.05

222018189.33

146710976.98

366819369.84

Figure 19–1 Thomas Periodic Table

Covalent BondingCovalent bonding is the mechanism of electron sharing that binds atoms together to form mole-cules. In covalent bonding, a bond is made of a pair of electrons shared by two atoms. More com-plex electron structures may share one, two, or three electron pairs between atoms. Examples ofthis include:

• Hydrogen (H2) has one bond between the hydrogen atoms H - H• Oxygen (O2) has two bonds between the oxygen atoms O � O• Nitrogen (N2) has three bonds between the nitrogen atoms N � N

Covalent bonds have unique properties, one of which is that they are not limited to atoms ofthe same element or to only two atoms for each molecule. Common examples include water(H2O), ammonia (NH3), carbon dioxide (CO2), and methane (CH4). In the water molecule, theoxygen atom forms two covalent bonds with the hydrogen. In the ammonia molecule, three bondsare shared with the nitrogen. One of the most useful covalent bonds is found with the elementcarbon. Carbon atoms tend to form four covalent bonds because there are four electrons in theouter shell; this leaves the outer shell in the carbon atom four electrons short. Because of thenumerous opportunities for bonding, some carbon compounds are made of tens of thousands ofatoms. Crude oil is a good example of how hydrogen and carbon link together to form a varietyof hydrocarbon chains: methane, ethane, propane, butane, pentane, octane, decane, and muchlarger hydrocarbons. Other common hydrocarbons include kerosene, gasoline, jet fuel, light oil,heavy oil, and asphalt.

402


Electron Configuration

Element EC Atomic #

Hydrogen 1s1 1

Helium 1s2 2

Lithium 1s22s1 3

Beryllium 1s22s2 4

Boron 1s22s22p1 5

Carbon 1s22s22p2 6

Nitrogen 1s22s22p3 7

Oxygen 1s22s22p4 8

Fluorine 1s22s22p5 9

Neon 1s22s22p6 10

Phosphorus 1s22s22p63s23p3 15

Calcium 1s22s22p63s23p64s2 20

Manganese 1s22s22p63s23p64s23d5 25

Zinc 1s22s22p63s23p64s23d10 30

Bromine 1s22s22p63s23p64s23d104p5 35

Another type of bonding is called ionic bonding. Ionic bonds are best described as magnetic-typebonds. In this process, one or more electrons transfer from one or more atoms to another atom,creating a positive ion and a negative ion that attract or hold to each other. These type of bondsare very strong. An example of a compound with ionic bonding is sodium chloride (NaCl).To betterunderstand ionic bonds, spend some time reviewing ions and how they are formed.

Most molecular bonds are covalent. However, in solids there are four bonding entities or mecha-nisms: ionic, covalent, metallic, and van der Waals.

19.3 Organic Chemistry

Organic chemistry is frequently described as the study of compounds that contain carbon. Lifeas we understand it depends on water and on the compounds of carbon. Water is the fluid of lifeand combines with carbon compounds to form covalent entities; in combination with hydrogen,oxygen, nitrogen, sulfur, and phosphorus atoms, these form the building blocks of life. Crude oilis composed of things that were once living on the face of the earth. Carbon compounds can befound in all living things. Simply put, organic chemistry is the chemistry of carbon compounds.

Methane is a simple hydrocarbon (a compound made of carbon and hydrogen) and is describedas tetravalent because it has four valence electrons that form covalent bonds. The alkane groupincludes methane (CH4), ethane (C2H6), propane (C3H8), butane (C4H10), pentane (C5H12), hexane(C6H14), heptane (C7H16), octane (C8H18), nonane (C9H18), decane (C10H22), undecane (C11H24),dodecane (C12H26), tridecane (C13H28), tetradecane (C14H30), pentadecane (C15H32), hexadecane(C16H34), heptadecane (C17H36), octadecane (C18H38), nonadecane (C19H40), eicosane (C20H42),triacontane (C30H62), and undecahectane (C111H224). Alkanes are chemical compounds that con-sist of atoms of carbon and hydrogen linked together by a single bond. These compounds are es-sential in the chemical processing industry.

Formulas for hydrocarbon compounds may be expressed with a type of shorthand notation. Forexample, propane has a shorthand formula CH3-CH2-CH3 that is more accurately called a con-densed structural formula.When using the shorthand formula, it is important to remember that thereal compound and the three carbons are not in a straight line; rather, they are connected at a 110-degree angle.

19.4 Balancing Equations

Being able to balance a simple equation is an important part of working in the chemical industry.The raw materials that go into the development of new products on a commercial scale are veryexpensive. Balancing equations allows a technician to accurately determine the amount of reac-tants needed or products to be made.

An unbalanced equation may include:

• Initial reactants• Final products• Process conditions (heat, temperature, pressure, analytical variables)

19.4 Balancing Equations

403

An unbalanced chemical equation will not yield the correct quantities. The law of conservation ofmatter is satisfied only when an equation is balanced. The total amount of reactants must equalthe total amount of products; in other words, “what goes in must come out.” Correct proportionsare involved at every step of a chemical process.

When looking at a chemical equation, the number immediately to the left of the chemicaldetermines the molecules or mole units. For example, 2H2O indicates that there are two water mol-ecules. Another common equation found in the chemical processing industry is

CH4 � 2O2 → CO2 � 2H2O

In this equation, methane (CH4) burns and consumes oxygen (O2) while producing carbon dioxide(CO2) and water (H2O). In this balanced equation, one methane molecule reacts with two oxygenmolecules to produce one carbon dioxide molecule and two water molecules. Another similarequation involves propane instead of methane:

CH3-CH2-CH3 � O2 → CO2 � H2O

We can clearly see that the equation is not balanced. To balance the two sides, we would need tomake the following adjustment:

CH3-CH2-CH3 � 5O2 → 3CO2 � 4H2O

After this adjustment, the chemical equation for oxidation of propane to carbon dioxide and wateris balanced.

When balancing an equation, the following principles are very helpful:

• Determine if the equation is balanced or not.• Never touch the subscripts. For example, in H2O, leave the subscript 2 alone;

a change will alter the composition of the compound and the substance itself.• Focus on the coefficients to balance an equation. Work from one side to the other.

Typically it is easiest to start with one side and then balance the other. Most operations move left to right, trial and error.

• Ensure that you have accounted for each source of a particular element that you are at-tempting to balance. It is possible that two or more molecules contain the same element.

• Adjust the coefficient of monoatomic elements last.• Adjust the coefficient of polyatomic ions that are acting as a group in self-contained

groups on both sides of the equation.

EXAMPLE

Not balanced (NH4)2CO3 → NH3 � CO2 � H2O

Balanced (NH4)2CO3 → 2NH3 � CO2 � H2O

Reactants Products

Nitrogen � 2 Nitrogen � 2

Hydrogen � 8 Hydrogen � 8

Carbon � 1 Carbon � 1

Oxygen � 3 Oxygen � 3

404


Each reaction will present its own mystery and problem, but most can be solved using theinspection method used here.

Practice ProblemsBalance the following equations:

1. Sn � Cl2 → SnCl4

Answer: Sn � 2Cl2 → SnCl4

2. Fe � O2 → Fe2O3

Answer: 4Fe � 3O2 → 2Fe2O3

3. CaO � HCl → CaCl2 � H2O

Answer: CaO � 2HCl → CaCl2 � H2O

4. Balance the following butane combustion equation.

C4H10 � O2 → CO2 � H2O

Answer: 2CH3-CH2-CH2-CH3 � 13O2 → 8CO2 � 10H2O

19.5 Petroleum Refining: Distillation

Converting raw materials into useful products such as gasoline, diesel, jet fuel, or light oils is knownas petroleum refining.Refining is done on crude oil—the substance whose price has fluctuated widelyrecently and caused tremendous and volatile swings in the economy as a whole. Because so manyproducts begin with crude oil, or depend on it for manufacturing processes or transportation, high oilprices mean high prices at the gasoline pump and higher prices on almost everything we purchase.

An essential part of petroleum refining is distillation. Distillation is a process used to separate thecomponents in a mixture by their volatilities in a boiling liquid mixture. Typically, distillation is partof a much larger chemical or refining process.

Distillation can be used to:

• Separate salt from sea water• Separate oxygen, nitrogen, and argon from air• Produce higher alcohol content in fermented solutions• Separate various components in crude oil

In a laboratory environment, distillation glassware is used to conduct bench-top operations. On asmall scale, these operations can be carefully controlled and provide relevant data applicable to alarge-scale commercial unit. The feedstock is placed in the bottom flask and heated up to opera-tional conditions. As the feed heats up, the separation process begins. Initially, bubbles form andthen begin to break the surface of the liquid.The lighter components in the mixture have the highervolatility; thus, they will overcome atmospheric pressure first and escape the rapidly moving mole-cules in the liquid.The initial boiling point of the mixture is quite different from the final boiling point.As the vapors initially move up the distillation column, they come into contact with the cooler glass


405

surfaces of the trays and return to the liquid state, transferring heat to the trays, downcomers, andshell. As the liquids begin to accumulate on the trays, the rising vapors gently lift the liquid, creat-ing good liquid-vapor contact as the liquids drop down the column and the vapors rise. Heat energyis transferred from areas of hot to cold as the vapors continue to rise from the lower trays to the topof the column. Each tray has a permeable liquid seal on the bottom. The downcomer’s lower tip issubmerged in the liquid, forming a liquid seal through which vapor must pass in order to move upthe column. Each tray acts as an individual still. Over time, each tray in the column will collect a sub-stance with a different molecular structure, with the lighter molecules in the top and the heavier onesin the bottom. At some time in the distillation process, the majority of the lighter components willvaporize, flow out the top of the column, and be condensed in the overhead condenser. At this point,the component with the next highest volatility will start to vaporize. As the initial boiling point grad-ually moves toward the final boiling point, the level in the bottom flask begins to decrease.

During some operations, the vapor appears to pulse upward one to three trays at a time. It is alsopossible to see one or two dry trays in the column while the other sections have a good liquid levelabove the tray. If the column is being pushed too hard, the upper trays may flood and cause prob-lems in the lower section of the column. It is also possible to see the transfer of heat energy in thecondenser as fluid passes in opposite directions. In a glass distillation bench-top operation, it iseasy to observe occurrences and record data that are not visible on a large-scale operation.

The equipment in a bench-top setup includes:

• Bottom flask and temperature indicator• Bottom flask heating mantle• Distillation column• Overhead condenser and cooling water• Overhead flask

Dalton’s law of partial pressures (Ptotal � P1 � P2 � P3) can be applied to a distillation system.Dalton’s law states that the total pressure of a gas mixture is the sum of the pressures of the indi-vidual gases (the partial pressures). A distillation system is by nature designed to separate thecomponents in a mixture. As the mixture is heated in a heat exchanger or fired heater, the pipingkeeps the liquid confined as it expands, artificially shifting the boiling point. The feed rate to thecolumn is carefully controlled. The heated mixture enters the column on the feed tray and rapidlyexpands, with the lighter components vaporizing and the heavier liquids cascading down the in-ternals of the column until they gain enough heat energy to flash or vaporize.The different trays inthe column are filled with vapors and liquids.

If you know the vapor pressure exerted by a specific chemical, you can calculate its partial pres-sure on the various trays. Figure 19–2 illustrates the partial pressure principle. For example, a mix-ture of hexane 25%, benzene 50%, and heptane 25% will exert a specific pressure at 175�F. Tocalculate the partial pressure, use the formula:

Partial pressure � vapor pressure � percent of fraction

Substance Vapor pressure @175°F Psia. Percent

Hexane 20.6 psia 25%

Benzene 14.7 psia 50%

Heptane 8.8 psia 25%

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Hexane � 20.6 psia � 0.25 � 5.15 psia

Benzene � 14.7 psia � 0.50 � 7.35 psia

Heptane � 8.8 psia � 0.25 � 2.20 psia

Total pressure � 14.70 psia

Using this information, we can calculate the total pressure on tray 9 by adding up the partialpressures.This information also illustrates that the chemical with the highest volatility is hexane(C6H14), which has a boiling point of 69�C. Heptane has a boiling point of 98�C and at 175�F(79.4�C) it represents the lowest percentage of the three components in vapor state above thetray.The larger the difference between the partial pressures, the easier it is to separate the frac-tions by boiling point.

Original Feed % BP

Hexane, C6H14 5.15 � 14.7 � .35 � 100 � 35% 25% 69�C

Heptane, C7H16 2.2 � 14.7 � .15 � 100 � 15% 25% 98�C

Benzene, C6H6 7.35 � 14.7 � .5 � 100 � 50% 50%


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FE FT

TE

TE

TT

I P

FIC

TIC

ºF

ºF SP PV OP% %

DPT

Dalton’s Law Partial Pressures

TE

TE

TE

Feed Tray #7

Tray #6

Tray #8

Tray #9

175ºF Feed Mix

P total

P total

= 7.35 + 5.15 + 2.2

= 14.7 psia

Benzene 50% 14.7 psia @ 175ºF Hexane 25% 20.6 psia @ 175ºF Heptane 25% 8.8 psia @ 175ºF

Vapor Pressure @ 175ºF Benzene 50% 14.7 X .05 = 7.35 psia Hexane 25% 20.6 psia X .25 = 5.15 psiaF Heptane 25% 8.8 psia X .25 = 2.2 psia

Benzene 50% Hexane 35% Heptane 15%

Tray #10

FT

I P

FIC

FO

Figure 19–2 Dalton’s Law of Partial Pressures

19.6 Aromatic Hydrocarbons

Benzene is the most common aromatic hydrocarbon. Chemists have determined that aromaticcompounds include both hydrocarbons and compounds that cannot be classified as hydrocarbons.The benzene molecule has six carbon atoms connected in a ring. Each carbon atom has fourbonding sites available; however, in benzene, three are used and one is free. The three bonds arecovalent; the fourth can be shared by all six carbon atoms. This creates a donut-shaped cloud oraromatic ring. Figure 19–3 shows the true benzene ring.

The benzene ring may have some of its six hydrogens replaced by other groups. (Reactions withbenzene are by substitution and not addition.) These compounds are found in Figure 19–4 andshould be memorized. The groups within the hydrocarbon family include:

• Alkane—Single covalent bonds• Alkene—Double bonds• Alkyne—Triple bonds• Cycloalkane—Contains a ring or cycle of carbons• Aromatic—Contains at least one highly unsaturated six-carbon ring

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Figure 19–3 True Benzene Ring

H

H

C

C

C

C C

C

H

H

H

H

H

H

H

H H

H

Benzene- a total of six electrons can be found in the donut-shaped clouds.

19.7 Alkenes and Alkynes

The suffix “-ene” is used to describe carbon-carbon double bonds. Let’s build on the foundation ofthe alkane family: We have seen that these compounds fit the general formula CnH2n�2. For ex-ample, ethane (C2H6) uses n as 2 and 2n � 2 is 6. However, alkanes can combine with a varietyof carbon and hydrogen proportions. Using ethane as a model, we remove two hydrogen atoms,one from each methyl group. This process removes the proton and electrons, allowing the hydro-gen atoms to combine to form a diatomic molecule held together by a covalent bond. What is thefate of the two unpaired electrons that remain on the carbons we removed the hydrogen from?Figure 19–5 shows what the process looks like. It is possible for these two electrons to pair up andform a second covalent carbon-carbon bond. Hydrocarbons that have carbon-to-carbon doublebonds are known as alkenes.

19.7 Alkenes and Alkynes

409

Figure 19–4 Nomenclature of Benzene Derivatives

Cl

Chlorobenzene

Nitrobenzene

Toluene PhenolAniline BenzoicAcid

Ethylbenzene

Formulas that Represent Benzene asan aromatic (sextet) of Electrons

Benzene Represented using Lewis Structure(Must Draw Two Lewis Structures to be Correct)

Bromobenzene

OHC

O

HO

Br

CH CH

C

C

C

C C

C

H

H

H

H

H

H

NO

C

C

C

C C

C

H

H

H

H

H

H

2

2

NH 2

3

CH 3

The alkene group closely resembles the alkane family. Ethylene (CH2�CH2) is the first member of thealkene or olefin family.The next alkene is propene (C3H6), for which the shorthand formula is CH2�CH-CH3. By removing two hydrogens from any alkane, we can create an alkene. In molecules that have

two or three carbon atoms, the double bond can be on the first or second carbon. In the case of butene,if the double bond is between the first and second carbon, it is called 1-butene: CH2�CH-CH2-CH3 �H2. If it is between the second and third carbon, it is called 2-butene: CH3-CH�CH-CH3 � H2.

If a carbon chain has four or more carbon-carbon bonds, we number the position of the doublebond using the lower available number. Compounds with two or more double bonds take the suf-fix “-diene” or “triene.” For example, 1,3 butadiene is shown as CH2�CH-CH�CH2. Ethylene andpropylene currently rank fourth and fifth in industrial chemical tonnage, just behind three inorganicchemicals (sulfuric acid, nitrogen, and oxygen).

Compounds in the alkynes family contain carbon-carbon triple bonds.The first member of this fam-ily is acetylene: HC�CH. Acetylene is the only alkyne that has widespread industrial usage; it is afuel for the oxyacetylene torch and welding applications.

Unlike the alkane family, the first members of the alkene and alkyne families have a range of odors,from slightly sweet to sharp and pungent. As previously mentioned, alkenes and alkynes are or-ganic compounds containing double and triple bonds and are referred to as unsaturated. Alkaneshave single bonds and are classified as saturated. A saturated hydrocarbon contains the maxi-mum number of hydrogen atoms and contains single covalent bonds. An unsaturated hydrocarboncan still accept an additional hydrogen.

Another group that should be discussed is the cycloalkane family. This group is characterizedwith a ring or cycle of carbons from three methylene groups located on the apex of the equilateraltriangle. Figure 19–6 illustrates this family. Examples of this group include:

cyclopropane, C3H6 (triangle) 3

cyclobutane, C4H8 (square) 4

cyclopentane, C5H10 (pentagon) 5

cyclohexane, C6H12 (hexagon) 6

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Figure 19–5 Ethane to Ethene

C C

H H

H H H H

Ethane

Ethene or Ethylene

:

: : : :

: :

C C H

H H

H :

: : : : :

C C

H H

H H

H H

C C H H

H H

19.8 Alcohols

Alcohols are compounds that contain �OH groups connected to an alkyl carbon. Phenols are sim-ilar, but have an �OH group connected directly to an aromatic ring. The terms primary, second-ary, and tertiary are used to describe alcohols. In a primary alcohol, a carbon can be connectedto one or no other carbon atoms; example: CH3-OH, methyl alcohol. A secondary is connected totwo carbons; example: isopropyl alcohol. Tertiary describes connections to three other carbons;example: tert-butyl alcohol (Figure 19–7).

Classify the alcohols in Figure 19–8 as primary, secondary, or tertiary, using the previous exam-ples as a guide.

Alcohols can be characterized as neutral compounds.When dissolved in pure water, the pH remainsneutral or 7. When an alcohol is combined with sulfuric or phosphoric acid and heated, it loses an

19.8 Alcohols

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Figure 19–6 The Cycloalkane Family

C

C

C

C

C

C C

C

H

Cyclohexane

Cyclopentane Cyclobutane Cyclopropane

2

H 2

H 2

H 2

C H 2

C H 2

C H 2 C H 2

C H 2

H 2

H 2

H 2

H 2

C H 2

C H 2

C H 2

C H 2 C H 2

C6 H12

C5 H10 C4 H8

C3 H6

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CH

OH

CH3 CH 3CH 2

Classification: Tertiary

Classification: Secondary

Common Name: tert-Butyl alcohol

C

CH 3

CH 3

CH 3

OH

Common Name: sec-Butyl alcohol

Classification: Primary

Common Name: Methyl alcohol

CH OH3

Figure 19–7 Primary, Secondary, and Tertiary Alcohols

Figure 19–8 (c) Tertiary Alcohol

Classification: Secondary

CH

OH

CH 3 CH 3 CH 2

Classification: Tertiary

C

CH 3

CH 3

CH 2 CH 3 OH

CH3-CH2-CH2-CH2-OH

Figure 19–8 (a) Primary Alcohol

Figure 19–8 (b) Secondary Alcohol

Summary

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OH group and a hydrogen atom on the adjacent carbon to form an alkene. This is possible in alco-hols that have at least one hydrogen atom on the adjacent carbon.Sodium hydroxide (NaOH) is clas-sified as a metallic hydroxide or base and produces OH� ions in water. Alcohols do not respond thisway because the �OH group in an alcohol is connected to the carbon atom by a covalent bond.

EthanolEthanol, CH3CH2OH, is often referred to as grain alcohol, because it has traditionally been pro-duced through a fermentation process using grains such as corn, rye, and wheat.Other stocks usedto produce ethanol include molasses from sugar cane, grapes, and potatoes. During the fermenta-tion process, sugars (C6H12O6) are converted to ethanol and CO2 using enzymes that are presentin yeast cells.Wine contains between 10 and 13% ethanol. Pure ethanol (95% � 5% water) is clas-sified as absolute alcohol. Recently ethanol has become popular as a gasoline additive.

Denatured alcohol (ethanol) has small quantities of methanol or benzene added. Both of these chem-icals are poisonous and are designed to make the ethanol unfit for drinking, thus avoiding any use ortaxation as liquor.The chemical additives do not affect the laboratory use of denatured alcohol.

MethanolMethanol, CH3OH, is sometimes referred to as wood alcohol, because at one time methanol wasmade from wood. Modern manufacturers produce methanol by subjecting hydrogen and CO3 toextremely high temperatures and pressures in the presence of a catalyst. Methanol is a toxic liq-uid used as a solvent for paints, varnishes, and the production of formaldehyde.

Ethylene GlycolEthylene glycol, HO-CH2CH2-OH, was commonly used as antifreeze in radiators, because of itsunique ability to lower the freezing point of water. Ethylene glycol also has a higher boiling pointthan water and provides additional protection from high and low temperature variations during op-eration. Because ethylene glycol is toxic when ingested, other products such as propylene glycolare now being used in its place.

Isopropyl Alcohol

Isopropyl alcohol or rubbing alcohol is used:

• to cool the skin by rapid evaporation (fever reduction)• to disinfect cuts and scrapes• as an astringent, to decrease pore size, limit secretions, and harden skin• as a cosmetic solvent

Summary

Science is a way of knowing and understanding the world we live in. The scientific method is de-scribed as the process by which or framework within which science operates. Key steps in the sci-entific method include a systematic, fact-based approach; asking questions; observing; analyzingobservations, and communicating observations. Scientists propose theories and hypotheses toexplain phenomena. A theory is a firmly grounded interpretation of confirmed observations. Ahypotheses is a tentative explanation of a small set of observations.

A mole is used to measure the mass of a sample by relating the number of atoms in a sample toits mass. A mole of any substance is its molecular formula weight expressed in grams. Avogadro’snumber is a universal constant that states the number of molecules in a mole: N0 � 6.023 � 1023

molecules/mole.

An easy way to handle large numbers is exponential (scientific) notation, a system based on thepowers of 10.

Elements are composed of identical atoms. Elements cannot be converted into other elements.Today we recognize 116 different elements. Carbon and hydrogen are the primary building blocksof the chemical and refining industry. Compounds are composed of two or more elements in well-defined ratios.

Three properties of an atom or ion are the atomic number, mass number, and electron configura-tion. The outermost shell in an atom is the valence shell. The electrons in the valence shell arecalled valence electrons. Elements have different arrangements and tend to react in an effort to fillthe valence shell.

Dmitri Mendeleev devised the first periodic table of elements, arranged by repetitions herecognized in the properties of elements. The current periodic table is organized in sequenceof increasing atomic number. Elements in the same vertical column or group have similar prop-erties. In columns 1, 2, and 13–18, representative elements extend above the rest. Theelements found in columns 3–12 are transition elements. Elements 58–71 and 90–103 areinner transition elements.

The elements on the periodic table are classified as metals, nonmetals, metalloids, or noble gases.Metals have atoms that give up electrons, are malleable, and tend to be excellent conductors ofheat and electricity. Nonmetals do not conduct electricity and have atoms that tend to accept elec-trons. Inert or noble gases gases refuse to accept or give electrons.

Covalent bonding is the mechanism of electron sharing that holds atoms together to form mole-cules. In a covalent bond, atoms share a pair of electrons. More complex electron structures mayhave one, two, or three shared electron pairs between atoms. Covalent bonds are not limited toatoms of the same element or to only two atoms for each molecule. Carbon atoms tend to formfour covalent bonds because there are only four electrons in the outer shell.

In ionic bonding, magnetic-type bonds form between ions with opposite charges. In this process,one or more electrons transfer from one or more atoms to another, creating a positive ion and neg-ative ion that attract or hold to each other. Solids may be bonded by one of four types: ionic, co-valent, metallic, and van der Waals.

Being able to balance equations allows a technician to accurately determine the correct amountof reactants or products. The total amount of reactants must equal the total amount of products.An unbalanced equation may include initial reactants, final products, process conditions, and heat,temperature, pressure, and analytical variables, but it will not include the correct quantities. In achemical equation, the number immediately to the left of the chemical determines the moleculesor mole units. Use the following principles when balancing an equation:

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• Determine if the equation is balanced or not.• Never touch the subscripts.• Focus on the coefficients, working from one side of the equation to the other.• Ensure that you have included each source for a particular element that you are

attempting to balance.• Adjust the coefficient of monoatomic elements last.• Adjust the coefficient of polyatomic ions that are acting as a group in self-contained

groups on both sides of the equation.

Petroleum refining converts raw materials into useful products. Distillation, a process used to sep-arate the components in a mixture by their volatilities in a boiling liquid mixture, is often used in re-fining. Dalton’s law of partial pressures (Ptotal � P1 � P2 � P3) can be applied to a distillationsystem.

Organic chemistry is the study of compounds that contain carbon. Life as we know it depends onwater and on the compounds of carbon; in combination with hydrogen, oxygen, nitrogen, sulfur,and phosphorus, carbon atoms form the building blocks of life. Crude oil is composed of things thatwere once living on the face of the earth.

The hydrocarbon family includes alkanes (single covalent bonds), alkenes (double bonds),alkynes (triple bonds), cycloalkanes (contain a ring or cycle of carbons), and aromatics (containat least one highly unsaturated six-carbon ring).

Alkanes are chemical compounds that consist of carbon and hydrogen atoms linked together bya single bond. Methane is a tetravalent simple hydrocarbon or carbon compound.

The suffix “-ene” is used to describe the double bonds formed in alkenes.The alkene group closelyresembles the alkane family. By removing two hydrogens from any alkane, we can create an alkene.

In molecules that have two or three carbon atoms, the double bond can be on the first or secondcarbon. In the case of butene, if the double bond is between the first and second carbon, it is re-ferred to as 1-butene.

Compounds in the alkynes family contain carbon-carbon triple bonds. Acetylene is the only alkynethat has widespread industrial usage.

The cycloalkane family is characterized by a ring or cycle of carbons from three methylene groupslocated on the apex of an equilateral triangle.

Alcohols are neutral compounds: When dissolved in pure water, the pH remains neutral or 7.When an alcohol is combined with sulfuric or phosphoric acid and heated, it loses an OH groupand a hydrogen atom on the adjacent carbon to form an alkene. Alcohols that are commonlyused in industry include ethanol, methanol, ethylene glycol, and isopropyl alcohol.

Summary

415

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Chapter 19 Review Questions1. What is the formula weight of aspirin (C9H8O4)?

2. Describe the special characteristics of the alkane family.

3. List the first four members of the cycloalkane family and the distinguishing characteristicsof this group.

4. Describe the special characteristics of the alkene family.

5. Describe the special characteristics of the alkyne family.

6. Identify the classification and special characteristics of benzene.

7. Draw the benzene ring.

8. List the key steps in balancing a chemical equation.

9. Balance: CaO � HCl → CaCl2 � H2O

10. Balance: NaOH � SO2 → Na2SO3 � H2O

11. What is the molecular weight of (NH2)2CO?

12. How much does one mole of H2O weigh?

13. List the electron configuration for bromine.

14. List four different applications for distillation.

15. Cyclopropane is characterized by what shape?

Chemical Process IndustryOverviewAfter studying this chapter, the student will be able to:

• Describe industrial processes and systems.• Describe the economic impact of the U.S. chemical manufacturing industry.• Explain the importance of oil and gas exploration and production.• Identify the basic equipment used in power generation.• Describe the “life cycle” of wastewater—where it comes from and how it is

treated.• Explain the operation concepts associated with the mining and mineral, food

and beverage, pharmaceutical, and pulp and paper processing industries.

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Chapter 20 ● Chemical Process Industry Overview

Key TermsFood and beverage processing—industry segment that includes bakeries, breweries, dairies,meat packaging, shellfish processing, and the fishing industry.

Mining and mineral processing—industry segment that involves technicians in undergroundmining and open-pit mining. Mining is the systematic extraction of minerals from beneaththe surface or inside the pit. This process is also applied to nonmetallic minerals and rocks(e.g., coal mining).

Nuclear generators—reactors that produce an unlimited amount of heat that can be used toproduce steam, which can in turn be used to produce electricity or in a number of other usefulapplications.

Oil and natural gas exploration and production—location and extraction of hydrocarbonresources; the first step in providing aviation fuel, gasoline for motorized vehicles, light andheat for homes, and raw materials for industry to support the production of materials thatmake up our modern society.

Pharmaceutical industry—industry segment that maintains a close relationship withresearch, chemists, engineers, doctors, and the medical profession. The manufacturing side ofthis industry employs cutting-edge technologies associated with reactions, filtering, drying,and distillation.

Power generation companies—transport low-cost alternating current across great distancesusing power transformers to step down high voltages.

Power transformation—the conversion of energy into electricity. Methods for transformingpower into electrical power include: (1) steam turbines, (2) gas turbines, (3) wind turbines,(4) water turbines, and (5) diesel engines. These devices are connected to electric generators,where fuel cells produce electricity.

Pulp and paper industry—industry segment consisting of pulp and paper mills and convertingoperations. Pulp is made by chemically or mechanically separating wood fibers from nonfibrousmaterial.

Sewage—water that contains 0.1% solid waste matter produced by human beings. Sewage isfrequently referred to as wastewater. More than 80% of the sewage produced in the UnitedStates comes from industrial sources.

U.S. chemical manufacturing industry—economic bloc that produced more than $460 billionof export goods in 2003.

20.1 Industrial Processes

Industrial processes are categorized as petrochemical, refinery, environmental, or gas processes.At present, hundreds of different processes exist and are used in industry. Recently, the petro-chemical and environmental areas have significantly added to this overall total.The more common

petrochemical processes handle ethylene, olefins, benzene, ammonia, and aromatics. Popularrefinery operations include traditional crude distillation, reforming, cracking, isomerization coking,and alkylation. Since the early 1980s, environmental issues have been in the forefront of publicand industry consciousness. Much-used environmental systems are applied to water treatment,air pollution, solid waste, and toxic waste.

20.2 Chemical Manufacturing Petroleum Refining

The U.S. chemical manufacturing industry (see Figure 20–1) produced more than $460 billionworth of export goods in 2003. Chemical exports alone for 2003 were in excess of $91 billion. Thesecond-ranked industry is motor vehicles, with more than $61 billion in sales.

Chemical plants and refineries are a complex array of systems and operations designed to pro-duce specific products associated with the hydrocarbon family. The term chemical manufactur-ing petroleum refining is directly associated with refinery and chemical plant operation. Modernmanufacturing includes the use of equipment and technology directly related to this industry.This industry segment is primarily responsible for the design and development of the originalprocess technology program. As the program has expanded, a much larger family has beenincluded: natural gas and oil exploration and production, power generation, water and wastewatertreatment, mining and mineral processing, food and beverage processing, pharmaceuticalmanufacturing, and paper and pulp manufacturing. A much closer relationship now exists in

20.2 Chemical Manufacturing Petroleum Refining

419

Figure 20–1 Chemical Manufacturing Industry

college programs between manufacturing engineering technology, engineering technology, andprocess technology.

Refineries are designed to separate the various fractions found in crude oil into useful products,such as naphtha, gasoline, kerosene, light oils, heavy oils, and natural gases. Each of theseproducts is essential for keeping our global economy moving. Refineries receive crude oil andchemical from pipelines, ships, barges, rail cars, and trucks. These devices are used to transportmaterials from oil fields and markets around the world.

Chemical plants use the raw materials produced in the refinery to make the chemicals that are thebasis of products like plastics and synthetic rubber. Chemicals made by these processes are usedin the clothing and textile industry, automobile industry, pharmaceutical and medical industry,computer and electronic appliance industry, and in paint, fertilizers, and so on. Chemical plantsspecialize in the large-scale production of chemical feedstocks and products made from the ever-versatile hydrocarbons. Technicians may work inside a chemical plant manufacturing a specificchemical and be totally unaware of how and where that chemical product is being used in ourcomplex modern society.

20.3 Exploration and Production

Oil and natural gas exploration and production are the first step in providing aviation fuel, gaso-line for motorized vehicles, lights and heat for homes, and raw materials for industry to supportthe production of the myriad materials that make up our modern society. This includes plastics,fertilizers, medicines, and synthetic rubber. Our modern computer and information age would notexist without these products.

Our present educational systems do not eloquently describe the importance of explorationand production, which include both offshore and onshore drilling. Currently, approximately 25%of U.S. oil and natural gas production comes from offshore drilling rigs and facilities. Alaska isresponsible for 18% of the U.S. oil and gas market. The government owns a bit more than one-third of the property in the United States. More than half of this land is set aside asprotected areas, national parks, and wilderness areas. When oil and gas manufacturersdevelop hydrocarbon facilities on government lands, they are required to pay a royalty to thegovernment. Oil and gas manufacturers pay billions in taxes to individual states and the federalgovernment.

Many new technicians are curious about how the industry explores for oil and natural gas. Between1859 and the early 1900s, finding oil was a matter of luck; however, today we have the technologyto “see” what lies beneath the ground. Geologists look for a number of clues in rocks that suggestthe presence of oil. Oil is a fossil fuel that began forming more than 10 million years ago in shal-low seas, as tiny plants and animals called plankton died and sank into the mud and sand. Overtime, the remains of these organisms formed into sedimentary layers that contained little oxygen.In this environment, tiny microorganisms broke the fractions into carbon-rich compounds.The heatand pressure of the built-up layers distilled the resulting organic “soup” into crude oil and naturalgas. Drilling rigs are set in place after geologists have identified and evaluated a spot with potentialto yield oil (see Figure 20–2).

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20.3 Exploration and Production

421

Derrick

Blowout Preventer

Pipe Turntable

Casing

Drill String

Drill Collar

Bit

Electric Generator

Engine

Hoisting System

Kelly

Swivel

Mud Pit

Figure 20–2 Oil Rig

Modern geologists look at surface rocks and terrain. They also use satellite images, seismology,sniffers, and magnetometers to find oil. These modern methods have a 10% success rate. Globalpositioning satellites may assist in locating and marking potential drilling sites. (See Figure 20–3.)Technicians involved in exploration and drilling use a variety of equipment, including:

• Large diesel engines or electric generators• Hoisting systems or turntables• Rotating equipment—swivel, kelly, turntable, drill string (drill pipe, collars)• Casing• Circulation system—pipes, valves, pumps, mud-return line, shale shaker, shale slide,

mud mixing hopper, mud pits, reserve pit• Derrick• Blowout preventer

Offshore StructuresA drilling rig is, essentially, a structure designed to house equipment and technology that canbe used to explore for, drill for, and extract natural gas or oil from underground reservoirs. Thisactivity may be a land-based operation or a marine-based operation. An offshore drilling rigis more correctly identified as a platform. Platforms that have a producing well are calledproduction platforms. Operations whose primary purpose is drilling rest on floating rigs orsemisubmersible rigs.

It has been estimated that more than 4,000 offshore production facilities exist on the outer conti-nental shelf (OCS). These exploration wells can be drilled to depths of around 10,000 feet. Mostproduction systems are designed to operate at depths of 6,000 feet. Oil and gas product pipelinenetworks extend well off the continental slope. Offshore production rigs and drilling and productionplatforms can be classified as onshore platforms, fixed platforms, jackup rigs, semisubmersibles,drill ships, and tension-leg platforms.

Fixed platforms are built of concrete and steel and are firmly anchored to the sea bed for long-termproduction drilling. A semisubmersible platform has hollow legs that can be used as displacementtanks to raise, lower, or stabilize the platform. This type of platform is movable and typically isanchored to the sea floor by cables. Jackup platforms have movable legs that can be raised or

422


Figure 20–3 Oil Recovery

lowered; this type of platform can be moved from one location to another. Drill-ship rigs use globalpositioning systems (GPS) to drill for natural gas or oil. Tension-leg platforms allow deep-waterdrilling by anchoring to the sea floor and virtually stopping any vertical movement.

Offshore structures are relatively self-sufficient; they provide electrical generators, water desali-nators, sleeping facilities, communication stations, and modern amenities. Production platformsare connected by pipelines or floating storage units to onshore operations. Key process elementsof oil and gas recovery include: wellhead, production manifold, production separator, water injec-tion pumps, gas compressors, glycol process to dry gas, oil and gas export metering, and mainoil-line pumps.

20.4 Power Generation

Electricity generation is the first step in delivering power to consumers and the local community.Three important aspects of power generation include: electric power transmission, electricitydistribution, and electricity retailing (see Figure 20–4). Power generation requires the use of largeindustrial boilers to produce steam. Steam generators, or boilers as they are commonly called,are used by industrial manufacturers to produce steam. Boilers use natural gas as fuel to oper-ate the burners. Steam is used to turn steam turbines that are used as the primary driver for largecommercial electric generators. Steam generators are part of a complex network that also

20.4 Power Generation

423

Figure 20–4 Power Generation

includes valves, pipes, storage tanks, pumps, compressors, motors, steam and gas turbines,heat exchangers, cooling towers, instrumentation, and advanced computer technology. In addi-tion, a large assortment of electrical equipment, transformers, breakers, and wiring is also partof this network. Electricity can be as hazardous as the most lethal chemical, so safety trainingand safe operating practices are carefully embedded in the training program.

Electricity provides light, heat, and power for a variety of activities. Power generation companiestransport low-cost alternating current across great distances using power transformers to stepdown high voltages. Power generation plants use natural gas, oil, coal, hydroelectric, nuclear,wind, solar, tidal harness, or hydrogen as sources to produce heat or mechanical (rotational)energy. The power transformation methods used to convert heat or mechanical power intoelectrical power include:

• Steam turbines• Gas turbines• Wind turbines• Water turbines• Diesel engines

These devices are connected to electric generators, where fuel cells produce electricity.

Nuclear generators produce an unlimited amount of heat that can be used to produce steam thatcan be used to produce electricity or in a number of other useful applications. Cogeneration is aprocess that combines the generation of electricity and heat, using fossil fuels, syngas, biogas, orsolar power as fuel sources. Power generation and electric companies can be found in strategiclocations all around the world. This opens up many employment opportunities.

20.5 Water and Wastewater Treatment

Process technicians work in water and wastewater treatment facilities located around the world.(See Figure 20–5.) City water supplies require employees with strong backgrounds in processequipment and technology. Special licenses and certifications are required to work in these areas.Whether their jobs deal with safe drinking water supplies, wastewater treatment, or another partof the water system, technicians should receive highly specialized training.

Public water supplies are regulated and tested frequently for purity. Surface waters, rivers,streams, and lakes may be used as the original feed source. Depending on the specific charac-teristics of the water, a wide variety of purification techniques can be used, including settling, fil-tration, chlorination, demineralization, and mineral removal. The need for safe loading, storage,inspection, treatment, and transportation within the public water system means that this fieldcomprises a very complex set of processes. (See Figure 20–6.)

Wastewater treatment is an extremely important service-related industry that is carefully inte-grated into our society. Sewage is defined as water that contains one-tenth of 1% (0.1%) solidwaste matter produced by human beings. Sewage is frequently referred to as wastewater. Waste-water comes from sinks and toilets of homes, factories, offices, and restaurants. Sewage containsharmful chemicals and disease-producing bacteria. Without processing, this harmful material

424


20.5 Water and Wastewater Treatment

425

Figure 20–5 Wastewater Treatment

Figure 20–6 Water Treatment

SettlingBasin

Pump

Filter

Cooling Tower

would eventually find its way into our lakes, rivers, and oceans. Industry converts this harmful ma-terial into a semi-clear, harmless liquid called effluent.

More than 80% of the sewage produced in the United States comes from industrial sources.Primary treatment removes 50% of the heaviest solid material from the sewage. Secondary

treatment removes 85%–90% of the remaining solids; this step may use the activated sludgeprocess or the trickling filtration process. The third step, called tertiary treatment, may includechemical treatment, radiation treatment, microscopic treatment, or discharge of effluent intolagoons. Water treatment technicians work with a variety of process systems to improve waterquality before it is discharged into public water systems.

20.6 Mining and Mineral Processing

Mining and mineral processing technicians are involved in both underground mining andopen-pit mining. Mining is the systematic extraction of ore from beneath the ground surface orinside a pit. This process is also applied to nonmetallic minerals and rocks (e.g., coal mining).Underground mining (Figure 20–7) requires large capital investments in equipment and struc-tured mining systems. Entry into underground mines is by shafts, adits, spiral ramps, orinclines. Developmental workings consist of mine levels and sublevels dug into the deposits.These passageways are called drifts when they follow the deposits, and cross-cuts when theyare driven across the mineralization. Developmental workings on successive mine levels areconnected by passageways called raises when driven upward, and winzes when drivendownward.

Mining technicians use conveyors, drills, hand tools, pumps, pipes, valves, elevators, heavyequipment, and personal protective equipment. Exploration and development combine toform the preproduction stage of underground mining. During the exploration phase, newly

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Shaft Collar

Cross-Cut

Sump

Winze

Adit Loading Pocket

Ore Pass

Incline

Figure 20–7 Mining Methods

discovered mineral deposits are evaluated for total tonnage and grade, suitability for mining,and metallurgical recovery characteristics. Mine development starts if the initial evaluation in-dicates that sufficient quantities of quality deposits can be accessed in a cost-effective man-ner. The mining methods used depend on the strength of the ore and wall rock. These methodsinclude:

• Open stoping• Sublevel stoping• Vertical crater retreat• Room-and-pillar mining• Shrinkage stoping• Cut-and-fill stoping• Square-set stoping• Longwall mining• Top-slice stoping• Sublevel caving• Block caving

20.7 Food and Beverage Processing

The food and beverage processing industry (see Figure 20–8) is another important segment ofthe chemical processing industry. College programs prepare students to take entry-level positionsin a wide variety of areas. Food and beverage processing workers are found in bakeries, brew-eries, dairies, meat packaging, shellfish processing, and the fishing industry. Half of the tasks arecompleted with automated equipment, with the balance being done manually. Work may includeloading and unloading cartons on conveyors or rolling racks, packing boxes, keeping the areaclean, and doing equipment and system checks.

Operation of advanced automation requires skills, knowledge, and training beyond those receivedby typical workers. Computers and control systems that change temperatures, pressures, tanklevels, flows, and compositional values are part of the food and beverage manufacturing system.Many of the automated systems are unique and require hours of on-the-job training before atechnician can work unsupervised. Modern food and beverage manufacturers use equipmentand technology currently being taught by PTEC programs in local community colleges anduniversities.

In addition to working with these systems, technicians are required to use advanced qualityprinciples and safety techniques. Quality control includes the use and application of informationpresently being taught in local process technology programs. Employers look for technicians whoare team players, display a willingness to work and learn the job, and work well in diverse workgroups. As for other areas in the CPI, technicians must be dependable and committed to safe workpractices. Safety, health, and environment include training in principles that have direct applicationto the food and beverage industry.

The work in the food and beverage industry is physically demanding and has a lower pay struc-ture than for technicians working in the hydrocarbon processing industry. Many food and beveragecompanies work rotating shifts and use self-directed work teams.

20.7 Food and Beverage Processing

427

20.8 Pharmaceutical Manufacturing

Pharmaceutical manufacturers employ three techniques covered in local process technology pro-grams: bench-top operations, pilot plant operations, and full-scale manufacturing. The pharma-ceutical industry maintains a close relationship with researchers, chemists, engineers, doctors,and the medical profession. The manufacturing side of this industry employs cutting-edge tech-nologies associated with reactions, filtering, drying, and distillation. Advanced instrumentation andcomputer technology are found at every level of this operation. Technicians employed in this fieldare required to have advanced training and college degrees in process technology, chemistry,and/or engineering.

Pharmaceutical manufacturing (see Figure 20–9) is an exciting career that can be pursued inmany parts of the world. The work is considered high tech and cutting edge and in many aspectsis very challenging. Pharmaceutical plants are multipurpose, DEA-certified, and FDA-registered,with a complete spectrum of active pharmaceutical ingredient (API) production capabilities.Thesetypically include drying, process development, chemical synthesis, advanced micronization withstate-of-the-art jet mills, and dosage-form manufacturing suites. Pharmaceutical manufacturersdevelop high-purity, sophisticated chemicals in weights from gram quantities to hundreds of kilos.

The equipment and technology associated with pharmaceutical manufacturing include areas andtopics covered in process technology AAS degree programs. A special emphasis is placed on:

428


Figure 20–8 Food and Beverage Processing

• Cryogenic reactions (to �80�C)• Cryogenic volatile organic compound (VOC) condensers (to �73�C)• High-vacuum distillation• Monel reactors (50 gallon)• Stainless-steel reactors (200 to 1,500 gallon)• Glass-lined/Hastelloy reactors (50 to 2,000 gallon)• Plate columns (1,500 gallon)• Packed columns (2,000 gallon)• Hastelloy centrifuges• Reactor/drying systems• Filter-dryers for API manufacturing of high-purity, ultra-high-quality products• Temperature ranges from –80�C to 280�C• Solids processing systems• Hydrogenation to 35 bar• Mass spectrometers• Liquid and gas chromatographs• Infrared (IR) and ultraviolet (UV) spectrometers

Chemical reactions used in pharmaceutical manufacturing include:• Acetylenic chemistry• Aldol condensation• Ammonia reactions

20.8 Pharmaceutical Manufacturing

429

Aventis

Abbott

GlaxoSmithKline Cipla

Pfizer

Ranbaxy

Merck

Solvay Johnson & Johnson

AstraZeneca

OHM

Janssen

Figure 20–9 Major Pharmaceutical Manufacturers

• Chiral chemistry• Cryogenic reactions• Epichlorohydrin chemistry• Hydrogenization• Optical resolution• Hydride reduction• Sulfoxidation

Technicians working in the pharmaceutical industry will be in a competitive, well-paying, stableenvironment. Job movement tends to be from one pharmaceutical company to another withhigher pay. Job transfers and promotions are possible within companies. New advancements inequipment, technology, and pharmaceuticals will create an environment of lifelong learning andconstant change.The research side of pharmaceuticals is constantly investing in computing tech-nology and three-dimensional (3-D) molecular modeling to streamline drug creation and accel-erate regulatory compliance and approvals. Computers are also extensively used to predictbiologically active compounds and to load and analyze raw data from clinical trials.

20.9 Pulp and Paper Processing

A number of process technology programs are working with the pulp and paper industry to addspecific tasks relating to the desired skill sets for this field. Many of the core skills are covered inthe existing program, and with a few minor additions the program can be adapted to fit this indus-try segment. A paper and pulp industry operation is typically located in an area with abundant rawmaterials. These facilities spread out over many acres and closely resemble the scope of largechemical plants (Figure 20–10). This industry is composed of two sections: mills and convertingoperations.

Pulp and paper mills produce chemical, mechanical, and thermomechanical pulps to form paper,building papers, and form paper. Pulp is made by chemically or mechanically separating woodfibers from nonfibrous material. The typical process uses sodium hydroxide and sodium sulfide todissolve the nonfibrous material. Chlorine gas, hydrogen peroxide, chlorine dioxide, and sodiumperoxide can be used to bleach the paper.

Pulpwood is brought into the paper mill from local forests by truck. Raw wood is sent to a devicecalled a barker before it is sent to the chipper. Bark is removed from the trees in the barker, andthe stripped wood is then broken up into smaller chunks in the chipper. A screen ensures that uni-form wood chips are fed into the continuous digester, where chemicals are added, recovered, andadded again. This slurry is then sent to the bleaching section. From this point, the paper pulp issent to a section that includes a refiner, jordan, and cleaner. The cleaner has two separate flows:a wet side and a dry side. On the wet side, the water is removed from the treated pulp. A devicecalled the Fourdriner machine prepares the pulp before it enters the presses. From the presses,the material enters a series of dryers before going to a size press. Paper is rolled up using a devicecalled a roll winder. On the dry side of the cleaners, the pulp goes to a cylinder machine beforegoing to the presses and dryers. As you can tell from this brief description, the paper manufactur-ing industry uses specialized equipment to produce paper products; however, much of the equip-ment and technology discussion and education in local process technology programs can beapplied in this industry.

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Summary

431

Pulpwood

Barker

WashingBleaching

ChipperScreen

ContinuousDigester

PiTi

Chemical Recoveryand Regeneration

Blow Tank

RefinerJordanCleaners

Cylinder Machine

Presses

Dryers

Presses Dryers

Coaters Calenders

RollWinder

Coaters Calenders

RollWinderWet End

Fourdriner

Figure 20–10 Paper and Pulp Manufacturing

Summary

Chemical manufacturing petroleum refining, once associated directly with refinery and chemicalplant operation, has come to include natural gas and oil exploration and production, powergeneration, water and wastewater treatment, mining and mineral processing, food and beverageprocessing, pharmaceutical manufacturing, and paper and pulp manufacturing. Refineries sepa-rate the various fractions found in crude oil into useful products, and chemical plants use thoseraw materials to make chemicals used in the processes of the clothing and textile industry, theautomobile industry, the pharmaceutical and medical industries, the computer and electronicappliance industry, and in paint, fertilizers, and so on.

Refineries are designed to separate the various fractions found in crude oil into useful products.Each of these products is essential for keeping our global economy moving. Refineries receivecrude oil and chemical from pipelines, ships, barges, rail cars, and trucks, which transportmaterials from oil fields and markets around the world.

Chemical plants use the raw materials produced in the refinery to make chemicals that are in turnused to make products such as plastics and synthetic rubber.Chemical plants specialize in the large-scale production of chemical feedstocks and products made from ever-versatile hydrocarbons.

Industrial processes are categorized as petrochemical, refinery, environmental, or gas processes.There are hundreds of different processes, and the overall total has been expanded significantly bythe petrochemical and environmental. The more common petrochemical processes use ethylene,olefins, benzene, ammonia, and aromatics. Refinery operations include traditional crude distillation,reforming, cracking, isomerization coking, and alkylation. Environmental systems are applied towater treatment, air pollution, solid waste, and toxic waste.

Oil and natural gas exploration and production is the first step in providing aviation fuel, gasolinefor vehicles, light and heat, and raw materials for industry to support the production of the manymaterials that our modern society uses.This includes plastics, fertilizers, medicines, and syntheticrubber. Exploration and production include offshore drilling and onshore drilling.

Three important aspects of power generation include: electric power transmission, electricitydistribution, and electricity retailing. Power generation requires the use of large industrial boilersto produce steam.

Public water supplies are regulated and tested frequently for purity. Surface waters, rivers,streams, and lakes may be used as the original feed source. Depending on the specific charac-teristics of the water, a wide variety of purification techniques may be used, including settling,filtration, chlorination, demineralization, and mineral removal.Technicians working with water sup-plies or wastewater treatment should receive highly specialized training; also, special licenses andcertifications are required to work in these areas.

Mining and mineral processing technicians are involved in underground mining and open-pit mining,processes that systematically extract ore from beneath the surface of the ground or the inside of apit. This process is also applied to nonmetallic minerals and rocks (e.g., coal mining). Undergroundmining requires large capital investments in equipment and structured mining systems.

The food and beverage processing industry is another important part of the chemical processingindustry. College programs prepare students to take a wide variety of entry-level positions in bak-eries, breweries, dairies, meat packaging, shellfish processing, and the fishing industry. Althoughsome tasks are completed with automated equipment, the balance are done manually.Tasks mayinclude loading and unloading conveyors or rolling racks, packing boxes, keeping the area clean,and doing equipment and system checks.

Pharmaceutical manufacturers used three techniques being taught in local process technologyprograms: bench-top operations, pilot plant operations, and full-scale manufacturing. The phar-maceutical industry maintains a close relationship with researchers, chemists, engineers, doctors,and the medical profession. The manufacturing side of this industry employs the use of cutting-edge technologies for reactions, filtering, drying, and distillation. Advanced instrumentation andcomputer technology are used at every level of this operation. Technicians employed in this areaare required to have advanced training and college degrees in process technology, chemistry,and/or engineering.

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Paper and pulp industry operations are typically located in areas with abundant raw materials.Thisindustry is composed of two sections: mills and converting operations.

Pulp and paper mills produce chemical, mechanical, and thermomechanical pulps to form paperand building papers. Pulp is made by chemically or mechanically separating the wood fibers fromnonfibrous material. These large facilities spread out over many acres and closely resemble largechemical plants.

Summary

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Chapter 20 Review Questions1. Describe three petrochemical processes.

2. Describe three refinery processes.

3. Describe how wood is turned into paper products.

4. Explain the close relationship between pharmaceutical manufacturing and the chemicalprocessing industry.

5. Describe the food and beverage processing industry.

6. Describe the different aspects of mining and mineral processing.

7. Explain the roles and responsibilities of water and wastewater treatment workers.

8. List the equipment that is used in both power generation and process technology.

9. Describe the importance of oil and gas exploration and production.

10. Describe the importance of wastewater treatment and water treatment.

Absorbed heat—transferred heat; effects in-clude increase in volume and temperature,change of state, electrical transfer, and chemicalchange.

Absorber—device used to remove selected com-ponents from a gas stream by contacting the streamwith a gas or liquid.

Acid—a chemical compound that has a pH valuebelow 7.0, changes blue litmus to red, yields hydro-gen ions in water, and has a high concentration ofhydrogen ions.

Adsorber—device (such as a reactor or a dryer)filled with porous solid designed to remove gasesand liquids from a mixture.

Air permits—government-granted licenses thatmust be obtained for any project that has the possi-bility of producing air pollutants.

Air pollution—contamination of the air, especiallyby industrial waste gases, fuel exhausts, or smoke.

Air-purifying respirator—breathing device that mech-anically filters or absorbs airborne contaminants.

Air-supplying respirator—breathing device thatprovides the user with a contaminant-free airsource.

Algebra—a branch of mathematics that uses let-ters to represent numbers and signs to represent

operations. It is a kind of universal arithmetic or,more simply, mathematics using letters.

Alkane group—family of hydrocarbons that arecomposed of carbon and hydrogen held together bysingle covalent bonds.

Alkylation—uses a reactor to make one large mol-ecule out of two small molecules.

Alkylation unit—uses a reactor filled with catalystto cause a chemical reaction that produces thedesired product.

AMU—see atomic mass unit.

API gravity—standard by which to measure theheaviness or density of a hydrocarbon; a speciallydesigned hydrometer marked in units API is used.

Applied General Chemistry—study of the generalconcepts of chemistry with an emphasis on indus-trial applications. Students measure physical prop-erties of matter, perform chemical calculations,describe atomic and molecular structures, distin-guish periodic relationships of elements, name andwrite inorganic formulas, write equations for chemi-cal reactions, demonstrate stoichiometric relation-ships, and demonstrate basic laboratory skills.

Applied Math for Process Technicians—varia-tions in this area include studies in two or more ofthe following areas; basic mathematics, technicalalgebra, math with applications, college algebra,

435

436

Glossary

statistics, trigonometry, statistics, applied or aca-demic physics.

Atmospheric pressure—the combined weight ofall the gases exerted on the surface of the earth. Atsea level, the total mass is estimated at 5.5 � 1015

tons, or 760 mmHg, or 14.7 psi, or one atmosphere.

Atom—the smallest particle of a chemical elementthat still retains the properties of the element. Anatom is composed of protons and neutrons in a cen-tral nucleus surrounded by electrons. Nearly all ofan atom’s mass is located in the nucleus.

Atomic mass unit (AMU)—the sum of the massesin the nucleus of an atom.

Atomic number—identifies the position of the ele-ment on the periodic table and the total number ofprotons in the atom.

Automatic/manual control—term describing twomodes in which controllers can be operated. Duringplant start-up, the controller is typically placed in themanual position. In this mode, only manual controlaffects the position of the control valve; it does notrespond to process load changes. After the processis stable, the operator places the controller in auto-matic mode, which allows the controller to super-vise the control loop function. At this point, thecontroller will automatically open and close the control valve to maintain the setpoint.

Balanced equation—axiom that the sum of the re-actants (atoms) equals the sum of the products(atoms).

Barometer—an instrument to measure atmos-pheric pressure; invented by Evangelista Torricelli in 1643.

Base—a chemical compound that has a soapy feeland a pH value above 7.0. It turns red litmus paperblue and yields hydroxyl ions.

Basic hand tools—term used to describe the typi-cal tools that process technicians use to performtheir job activities.

Batch process—order of work in which all ingredi-ents are added to the process up front.

Baume gravity—the standard used by indus-trial manufacturers to measure nonhydrocarbonheaviness.

Benzene—the most common aromatic hydrocarbon.The benzene molecule has six carbon atoms con-nected in a ring. Each carbon atom has four bondingsites available; in benzene, three are used and one isfree. The three bonds are covalent; the fourth can beshared by all six carbon atoms.This creates a donut-shaped cloud or aromatic ring. Reactions with ben-zene are substitution and not addition.

Bernoulli’s principle—states that in a closedprocess with a constant flow rate, changes in fluidvelocity (kinetic energy) decrease or increase pres-sure; kinetic-energy and pressure-energy changescorrespond to pipe-size changes; pipe-diameterchanges cause velocity changes; and pressure-energy, kinetic-energy (fluid velocity), and pipe-diameter changes are related.

Big Rollover—point at which global oil productionpeaks and then begins to decline.

Biogenic theory—describes how natural gas andcrude oil were formed using pressure or compres-sion and heat on ancient organic material.

Boilers—devices primarily designed to boil waterand generate steam for industrial applications. Boil-ers are classified as either water tube or fire tube.Steam generation systems produce high-, medium-,and low-pressure steam for industrial use.

Boyle’s law—at a constant temperature, thevolume of a gas is inversely proportional to itspressure.

V1—V2

�P2—P1

or P1V1 � P2V2

C&E diagram—see cause-and-effect diagram.

CAER—see Community Awareness and Emer-gency Response.

Cascade control—a term describing how one con-trol loop controls or overrides the instructions ofanother control loop to achieve a desired setpoint.

Catalyst—a chemical that can increase or de-crease a reaction rate without becoming part of theproduct. Catalysts are classified as adsorption, in-termediate, inhibitor, or poisoned.

Catalytic cracking—process that uses a catalystto separate hydrocarbons.

Catcracker—uses a fixed-bed catalyst to separatesmaller hydrocarbons from larger ones.

Catcracking—a process designed to increase theyield of desirable products from a barrel of crude oil;uses a catalyst to accelerate the separation process.

Cause-and-effect (C&E) diagram (fishbone dia-gram)—a method for summarizing available knowl-edge about the causes of process variation.

Charles’s law—at a constant pressure, the volumeof a gas is proportional to its absolute temperature.

V1—V2

�T1—T2

or V1—T1

�V2—T2

Chemical bonding (covalent)—occurs when ele-ments react with each other by sharing electrons.This forms an electrically neutral molecule.

Chemical bonding (ionic)—occurs when positivelycharged elements react with negatively charged ele-ments to form ionic bonds through the transfer of va-lence electrons. Ionic bonds have higher meltingpoints and are held together by electrostatic attraction.

Chemical equation—numbers and symbols thatrepresent a description of a chemical reaction.

Chemical processing industry (CPI)—businesssegment composed of refinery, petrochemical, pa-per and pulp, power generation, and food process-ing companies and technicians.

Chemical reaction—interactions between two ormore chemicals in which a new substance is formed;

a term used to describe the breaking, forming, orbreaking and forming of chemical bonds. Types in-clude exothermic, endothermic, replacement, andneutralization.

Chemistry—the science and laws that deal withthe characteristics or structure of elements and thechanges that take place when elements combine toform other substances.

Clean Air Act—legislation intended to enhance thequality of the nation’s air, accelerate a national re-search and development program to prevent air pol-lution, provide technical and financial assistance tostate and local governments, and develop a re-gional air pollution control program.

Clean Water Act of 1972—legislation adopting thebest available technology (BAT) strategy for allcleanups.

College programs in process technology—state-approved and regionally accredited programs that include courses such as Introduction to ProcessTechnology; Safety, Health, and Environment;Process Instrumentation; Process Technology 1—Equipment, PT 2—Systems, and PT 3—Operations;Process Troubleshooting; Principles of Quality; andapplied chemistry, physics, and basic math.

Combustion reaction—an exothermic reactionthat requires fuel, oxygen, and heat to occur. In thistype of reaction, oxygen reacts with another mate-rial so rapidly that fire is created.

Community Awareness and Emergency Re-sponse (CAER)—a program designed to informthe community surrounding a plant of potentiallyhazardous situations and of hazardous chemicalsfound in the plant, to work with the community to de-velop emergency response programs, and to openthe lines of communication between industry andthe community.

Community right-to-know—a principle holdingthat a community should be aware of the chemicalsmanufactured or used by local chemical plants andbusiness. Legislation, regulations, and programs

Glossary

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Glossary

based on this principle are intended to involve thecommunity in emergency response plans, improvecommunication and understanding between indus-try and the surrounding community, improve localemergency response planning, and identify poten-tial hazards.

Compound—a substance formed by the chemicalcombination of two or more substances in definiteproportions by weight.

Compressor—a device designed to accelerateor compress gases. Compressors come in twobasic designs: (1) positive displacement (rotaryand reciprocating), and (2) dynamic (axial andcentrifugal).

Compressor system—key elements of this systeminclude piping, valves, a compressor, a receiver,heat exchangers, dryers, back pressure regulators,gauges, and moisture removal equipment.

Control charts (SPC charts)—statistical toolsused to determine and control process variations.

Control loop—a collection of instruments that worktogether to automatically control a process (such aspressure, temperature, level, flow, or analytical vari-ables). A loop includes a primary element or sensor,a transmitter, a controller, a transducer, and a finalcontrol element. Information from control loops isinvaluable in the troubleshooting process.

Controller—device the primary purpose of which isto receive a signal from a transmitter, compare thissignal to a setpoint, and adjust the (final control el-ement) process to stay within the range of the set-point. Controllers come in three basic designs:pneumatic, electronic, and electric.

Controller modes—settings and functions thatinclude proportional (P), proportional plus integral (PI),proportional plus derivative (PD), and proportional-integral-derivative (PID). Proportional control is pri-marily used to provide gain where little or no loadchange typically occurs in the process. Proportionalplus integral is used to eliminate offset between thesetpoint and process variables; PI works best where

large changes occur slowly. Proportional plus de-rivative is designed to correct fast-changing errorsand avoid overshooting the setpoint; PD worksbest when frequent small changes are required.Proportional-integral-derivative is applied wheremassive, rapid load changes occur; PID reducesthe amount of swing between the process variableand the setpoint.

Cooling tower—device used by industry to removeheat from water. In a typical tower, a box-shapedcollection of multilayered slats and louvers directsairflow and breaks up water as it cascades from thetop of the water distribution system. Cooling towersare classified by the way they produce airflow andby the way the air moves in relation to the downwardflow of water. Basic designs include atmospheric,natural, forced, and induced draft.

Cooling-tower system—includes a cooling-towerand pipe system to transfer cooled water to the unitand back to the cooling-tower water-distributionsystem. The cooling tower has a series of complexinstrument systems to control ppm, pH, level, tem-perature, fan speed, and flow rate.

Covalent bonding—the mechanism of electronsharing that holds atoms together to form mole-cules. In a covalent bond, atoms share a pair ofelectrons.

CPI—see chemical processing industry.

Cycloalkane family—group of hydrocarbons char-acterized by the presence of a ring or cycle of car-bons from three methylene groups located on theapex of the equilateral triangle.

Cyclone—a device used to remove solids from agas stream.

Dalton’s law of partial pressures—states that thetotal pressure of a gas mixture is the sum of thepressures of the individual gases (their partial pres-sures); Ptotal � P1 � P2 � P3.

Demineralizer—a filtering-type device that removesdissolved substances from a fluid.

Density—the heaviness of a substance.

Department of Transportation (DOT)—govern-mental agency empowered to regulate the trans-portation of goods on public roads and highways.

Derivative mode—see rate mode.

Distillation—a process used to separate the com-ponents in a mixture by their volatilities in a boilingliquid mixture.

Distillation column—a collection of stills stackedone on top of another; separates chemicalmixtures by boiling points. Distillation columns fallinto two distinct classes: plate and packed.

Distillation tower—a series of stills arranged sothe vapor and liquid products from each tray flowcountercurrently to each other.

Diversity training—identifies and reduces hiddenbiases between people with differences.

Dmitri Mendeleev—(1834–1907); a Russian pro-fessor of chemistry who devised the first periodictable of elements.

DOT—see Department of Transportation.

Educational credentials—job qualifications earnedthrough school study; include a one-year certificateor a two-year AAS degree. Certificates may be levelone or level two.

Electrical drawings—graphical representationsthat use symbols and diagrams to depict an electri-cal process system.

Electrical system—system composed of a boiler,a steam turbine, a main substation with transform-ers, a motor control center, and electrically poweredequipment.

Electron—a negatively charged particle that orbitsthe nucleus of an atom.

Element—matter composed of identical atoms.

Elevation drawings—graphical representa-tions showing the location of process equipmentin relation to existing structures and groundlevel.

Emergency response—actions taken when anemergency occurs in an industrial environment;how specific individuals act during an emergencysituation. The employer must have a written plan,setting out and documenting these actions, thatfollows a specific set of standards. Drills are care-fully planned and include preparations for worst-case scenarios (e.g., vapor releases, chemicalspills, explosions, fires, equipment failures, hurri-canes, high winds, loss of power, and bombthreats or bombings).

Endothermic reaction—a reaction that requiresexternal heat or energy to take place.

Energy—anything that causes matter to changeand does not have the properties of matter.

Environmental Protection Agency (EPA)—a fed-eral agency with authority to make and enforceenvironmental policy.

Equipment failure—occurrence when equipmenthas broken, ruptured, or is no longer responding toits design specifications.

Equipment location drawings—show the exactfloor plan location of equipment in relationship tothe plant’s physical boundaries.

Estimated ultimately recoverable (EUR)—technical term describing the total amount ofcrude oil that will ultimately be recovered. Thisnumber is difficult to calculate and fluctuates fre-quently. Oil reserves are typically underestimatedand are adjusted as additional information andnew technology become available. Most expertsbelieve that 1.2 trillion barrels (without oil sands)and 3.74 trillion barrels (with oil sands) reflect theworld’s total endowment of oil.

Exothermic reaction—a reaction that producesheat or energy.

Glossary

439

Exponential (scientific) notation—a numbersystem based on powers of 10 (exponents), de-signed to make it easier to work with very largenumbers.

Extract—composed of the solute and the heaviersolvent; will layer out or naturally separate from thelighter raffinate. The heavier extract does not flowover the weir; rather, it goes out the extract dis-charge port.

Extruder—a complex piece of equipment com-posed of a heated jacket, a set of screws or ascrew, a heated die, a large motor, a gearbox, anda pelletizer. An extruder converts raw plastic mate-rial into pelletized plastics ready for further pro-cessing into finished products. Most extruders usea single- or twin-screw design surrounded by aheated barrel. The molten polymer is forced orpumped through a die.

Faculty expectations—college faculty’s assump-tion that process technology students will be re-sponsible for their own learning, setting goals,managing their time, participating in class activities,and attending scheduled class meetings.

Fail open/fail closed—term used in troubleshoot-ing that describes how a control valve ceases towork (fails): in the open or the closed position.

Feed system—composed of a variety of equipmentsystems, including feed tanks, valves, piping, in-struments, and pumps.

Filter—device that removes solids from fluids.

Fire-tube heaters—furnaces consisting of a bat-tery of tubes that pass through a firebox. Firedheaters or furnaces are commercially used to heatlarge volumes of crude oil or hydrocarbons. Basicdesigns include cylindrical, cabin, and box.

First responder—person who undertakes the firsttwo levels of emergency response as described byHAZWOPER (29 C.F.R. §1910.120). The first re-sponder awareness and operations levels set out aseries of structured responsibilities. The awareness

level teaches a technician how to recognize ahazardous chemical release, the hazards associ-ated with the release, and how to initiate the emer-gency response procedure. The operations levelteaches a technician how to safely respond to a re-lease and prevent its spread.

Fixed-bed reactor—device in which the fixedmedium remains in place as raw materials passover it.

Flare system—safely burns excess hydrocarbons.A flare system is composed of a flare, knock-outdrum, flare header, fan optional, steam line andsteam ring, fuel line, and burner.

Flow diagram—a simplified diagram that usesprocess symbols to describe the primary flow paththrough a unit.

Flowchart—a picture of the activities that takeplace in a process.

Fluid catalytic cracking—a process that uses a re-actor to split large gas oil molecules into smaller,more useful ones.

Fluid coking—a process that uses a reactor toscrape the bottom of the barrel and squeeze lightproducts out of the residue.

Fluid flow—movement of fluid particles; can be de-scribed as laminar, turbulent, parallel, series, coun-terflow, or cross-flow.

Fluidized-bed reactor—suspends solids within thereactor by countercurrent flow of gas. Particle seg-regation occurs over time as heavier componentsfall to the bottom and lighter ones move to the top.

Food and beverage processing—industry seg-ment that includes bakeries, breweries, dairies,meat packaging, shellfish processing, and the fish-ing industry.

Forms for collecting data—can vary from notesjotted down on a napkin to complex, preprinted doc-umentation tools.

440

Glossary

Foundation drawings—diagrams containing con-crete, wire mesh, and steel specifications that iden-tify width, depth, and thickness of footings, supportbeams, and foundation.

Fractional distillation—a process that separatesthe components in a mixture by their individual boil-ing points.

Fractionating column—the central piece of equip-ment in a distillation system. Fractionating columnsseparate hydrocarbons by their individual boilingpoints.

Frequency plot—see histogram.

Furnace system—typically used to heat up largequantities of hydrocarbons or chemicals. The basicequipment in a furnace system includes a furnace,advanced process control systems and instru-ments, pump systems, compressor systems, andfuel systems.

Future hiring trends—directions in employment;large numbers of retiring “baby boomers” will haveto be replaced in the chemical processing industry.

Goal setting—establishment of reasonable, spe-cific, measurable objectives that lead toward thesuccessful achievement of a goal.

Gold collar—term used to describe processtechnicians.

Hazard communication (HAZCOM) standard—known as “workers’ right to know,” ensures thatprocess technicians can safely handle, transport,and store chemicals.

HAZWOPER—hazardous waste operations andemergency response.

Heat—a form of energy caused by increasedmolecular activity. Forms include sensible heat andlatent heat.

Heat exchanger—an energy-transfer device de-signed to convey heat from one substance to

another. Basic designs include pipe coil, shell-and-tube, air-cooled, plate-and-frame, and spiral.

Heat exchanger system—consists of shell in/outpiping; tube in/out piping; valves; instruments; flow,temperature, analytical, and pressure control loops;and two separate pump systems.

Heat transfer—transmission of heat (movement ofheat energy) through conduction (heat energy trans-ferred through a solid object; e.g., a heat exchanger),convection (heat transferred by fluid currents from aheat source; e.g., the convection section of a furnaceor the economizer section of a boiler), or radiation(heat energy transferred through space by means ofelectromagnetic waves; e.g., the sun).

Histogram (frequency plot)—a graphical toolused to understand variability. The chart is con-structed with a block of data separated into 5 to12 bars or sections from low number to high num-ber.The vertical axis is the frequency and the hori-zontal axis is the “scale of characteristics.” Thefinished chart resembles a bell if the data is incontrol.

Housekeeping—maintenance of cleanliness andorder; closely associated with safety in the chemi-cal processing industry. Process technicians are re-quired to keep their immediate areas clean.

Hubbert peak theory—describes how future worldpetroleum production will peak and then begin theprocess of global decline. This decline will closelymatch the former rate of increase, as known oilreservoirs move to exhaustion.

Hydrocarbons—a class of chemical compoundsthat contain hydrogen and carbon.

Hydrocracking—uses a multistage reactor systemto boost yields of gasoline from crude oil.

Hydrodesulfurization unit—sweetens productsby removing sulfur.

Hydrogen ion—positively charged hydrogenparticle.

Glossary

441

Hydroxyl ion—negatively charged OH particle.

Ideal gas law—combination of Boyle’s andCharles’s laws, expressed as:

P1V1�

P1V2

T1 T2

Improvement cycle—a four-phase system forquality improvement: plan, observe and analyze,learn, and act.

Industry training programs—programs whose pri-mary focus is on mandatory safety training and on-the-job training; however, a number of employers’programs still include some of the topics covered bycollege process technology courses.

Inertia—a principle that explains a body’s ability toresist motion.

Integral mode—see reset mode.

Introduction to Process Technology—a surveycourse of all the courses found in the regionally ac-credited process technology program.

Ion—electrically charged atom.

Ionic bonding—magnetic-type bonds. In ionicbonding, one or more electrons transfer from one ormore atoms to another, creating a positive ion andnegative ion that attract and hold each other. Thesebonds are extremely strong.

Job lists—information about potential employers;contain contact name, address, telephone number,and size of company.They can be obtained from thelocal chamber of commerce (a small fee may apply).

Job search—requires four to six months, a good re-sume and cover letter, a certificate or degree, goodinvestigative skills (to identify who is hiring and whoto contact), knowledge of application methods, in-terest cards, tests, and so on. Job searches are verydifficult and require serious dedication, time, and a“thick skin.”

Kinetic energy—the energy of motion or velocity.

Layer out—a process in which two liquids that arenot soluble separate naturally from each other (ex-ample: oil and water).

Legends—used to describe symbol meanings, ab-breviations, prefixes, and other specialized equip-ment; function like the key of a map.

Lifelong learning—ongoing process of learningabout new technologies and equipment. Globalcompetition requires companies to adopt new andinnovative techniques. Process technicians willcome into contact with learning opportunities thatcannot be found anywhere else.

Liquid pressure—the pressure exerted by a con-fined fluid. Liquid pressure is exerted equally andperpendicularly to all surfaces confining the fluid.

Lock-out/tag-out—term used to describe a pro-cedure for shutting down and making unavailable foruse equipment that falls under the control of haz-ardous energy regulations (29 C.F.R. §1910.147).

Lubrication system—system that includes a lubri-cant reservoir, pump, valves, heat exchanger, andpiping.

Mass—the quantity of matter in an object.

Material balancing—a method for calculating re-actant amounts versus product target rates.

Mathematics—field dealing with numbers andnumber operations. Process technicians use a vari-ety of mathematical and scientific functions to per-form their jobs. Some of the terms used in this areainclude:

• addition—a term applied to a mathematicaloperation for combining numbers.

• conversion tables—charts that displayequivalent units of measure.

• decimal point—the period or “dot”between whole numbers and fractionalnumbers.

• denominator—the bottom number in afraction.

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Glossary

• dimensional analysis—conversion within onesystem of units or to another system of units.Example: changing English-system feet to International System (SI) me-ters.

• division—a mathematical operation for de-termining how many times one number orquantity is contained in another number orquantity.

• divisor—the number by which one isdividing.

• fraction—a part of a whole amount.• grouping symbols—signs used to separate

functions in an equation.• lowest common denominator (LCD)—the

smallest whole number that can be used todivide two or more denominators.

• mixed number—a whole number and a frac-tion.

• multiplication—the process of adding anumber to itself a specified number of times.

• numerator—the top number in a fraction.• percent—a fractional amount expressed in

terms of parts per one hundred.• subtraction—a mathematical operation in

which one number is deducted fromanother.

Matter—anything that occupies space and hasmass or volume.

Mendeleev, Dmitri—see Dmitri Mendeleev.

Mining and mineral processing—industry seg-ment that involves technicians in undergroundmining and open-pit mining. Mining is the system-atic extraction of minerals from beneath thesurface or inside the pit. This process is also ap-plied to nonmetallic minerals and rocks (e.g., coalmining).

Mixture—composed of two or more substancesthat are only physically combined. Mixtures can beseparated through physical means such as boilingor magnetic attraction.

Mole—the molecular formula weight of any sub-stance expressed in grams.

Molecule—the smallest particle that retains theproperties of the compound.

Neutralization reaction—a reaction designed toremove hydrogen ions or hydroxyl ions from a liquid.

Neutron—a neutral particle in the nucleus of anatom.

Nuclear generators—reactors that produce an un-limited amount of heat that can be used to producesteam, which can in turn be used to produce elec-tricity or in a number of other useful applications.

Occupational Safety and Health Administration(OSHA)—Federal agency created by the Occupa-tional Safety and Health Act; composed of threedivision: the Occupational Safety and Health Ad-ministration, the National Institute for OccupationalSafety and Health, and the Occupational Safetyand Health Review Commission.

Oil and natural gas exploration and production—location and extraction of hydrocarbon resources;the first step in providing aviation fuel, gasoline formotorized vehicles, light and heat for homes, and raw materials for industry to support the pro-duction of materials that make up our modernsociety.

Organic chemistry—the study of compounds thatcontain carbon.

OSHA—see Occupational Safety and HealthAdministration.

P&ID—see piping and instrumentation drawing.

Packed distillation column—system filled withpacking to enhance vapor-liquid contact to separatethe components in a mixture by boiling point. Themost common types of packing include sulzer,rasching ring, flexiring, pall ring, intalox saddle, berlsaddle, metal intalox, teller rosette, and mini-ringpacking.The basic components of a packed columninclude a feed line, feed distributors, a shell, hold-down grids, random or structured packing, packingsupport grids, bed limiters, a bottom outlet, a top

Glossary

443

vapor outlet, instrumentation, and an energy bal-ance system. Packed columns are designed forpressure drops between 0.20 and 0.60 inches ofwater per foot of packing material.

Pareto chart—a simple bar graph with classifica-tions along the horizontal and vertical axes.The ver-tical axis is usually the number of occurrences, cost,or time.The horizontal axis orders the bars from themost frequent to the least frequent.

Pascal’s law—pressure in a fluid is transmittedequally in all directions, molecules in liquidsmove freely, and molecules are close together ina liquid.

Percent-by-weight solution—representation inwhich the concentration of the solute is ex-pressed as a percentage of the total weight of thesolution.

Periodic table—chart arranged by atomic numberthat provides information about all known elements(e.g., atomic mass, symbol, atomic number, boilingpoint).

Permit system—a regulated system that requires avariety of permits for various applications. The mostcommon applications are cold work, hot work, con-fined space entry, opening/blinding, permit to enter,and lock-out/tag-out.

Personal protective equipment (PPE)—gearused to protect a technician from hazards found ina plant. OSHA and EPA have identified four levels ofPPE that could be required during an emergencysituation. Level A provides the most protection; levelD provides the least.

PFD—see process flow diagram.

pH—a measurement system/scale used to deter-mine the acidity or alkalinity of a solution.

Pharmaceutical industry—industry segment thatmaintains a close relationship with research,chemists, engineers, doctors, and the medical pro-fession. The manufacturing side of this industry

employs cutting-edge technologies associated withreactions, filtering, drying, and distillation.

Physical hazard—name for a chemical that statis-tically falls into one of the following categories:combustible liquid, compressed gas, explosive orflammable, organic peroxide, oxidizer, pyrophoric,unstable, or water reactive.

Piping—used in industry to safely contain and trans-port chemicals; composed of a variety of materialsand configured in a variety of shapes and designs.

Piping and instrumentation drawing (P&ID)—acomplex diagram that uses process symbols to de-scribe a process unit.

Planned experimentation—a tool used to test andimplement changes to a process (aimed at reducingvariation) and to understand the causes of variation(process problems).

Plate distillation column system—has trays thatare designed to enhance vapor-liquid contact in thedistillation process. Plate columns may be bubble-cap, valve tray, or sieve tray.The basic components ofa plate distillation column include a feed line, feed tray,rectifying or enriching section, stripping section, down-comer, shell, reflux line, energy balance system, over-head cooling system, condenser, preheater, reboiler,accumulator, feed tank, product tanks, bottom line,top line, side stream, and advanced instrument con-trol system.

Potential energy—stored energy.

Power generation companies—transport low-cost alternating current across great distances us-ing power transformers to step down high voltages.

Power transformation—the conversion of energyinto electricity. Methods for transforming power intoelectrical power include: (1) steam turbines, (2) gasturbines, (3) wind turbines, (4) water turbines, and (5) diesel engines. These devices are connected toelectric generators, where fuel cells produce electricity.

PPE—see personal protective equipment.

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Glossary

Predicted model of shared responsibilities—forecast that the process technician of the future willtake over tasks and job responsibilities presentlyperformed by engineers and chemists.

Preemployment tests—examinations adminis-tered by potential employers to determine appli-cants’ job qualifications and readiness; examplesinclude the Bennett Mechanical ComprehensionTest (BMCT) by George K. Bennett (S & T version);the Richardson, Bellows, Henry & Company “Testof Chemical Comprehension” (S & T version, 1970);and the California Math Test. Types include readingcomprehension, accuracy checking, block count-ing, and tests developed in-house.

Pressure—force or weight per unit area (Force �Area � Pressure); measured in pounds per squareinch.

Pressure relief system—safety system that in-cludes relief valves, safety valves, rupture discs,piping, drums, vent stacks, pressure indicators,pressure alarms, pressure control loops, and flaresystems.

Primary operational problem—term for the firstissue (problem) that created a process upset.

Principles of Quality—course covering the back-ground and application of quality concepts.Topics in-clude team skills, quality tools, statistics, economics,and continuous improvement. Focuses on the appli-cation of statistics, statistical process control, math,and quality tools to process systems and operations.

Process—a collection of equipment systems thatwork together to produce products (e.g., crudedistillation).

Process equipment—piping, tanks, valves,pumps, compressors, steam turbines, heat ex-changers, cooling towers, furnaces, boilers, reac-tors, distillation towers, and so on; all the primarymachines and devices used in a process.

Process flow diagram (PFD)—chart used to out-line or explain the complex flow, equipment,

instrumentation, electronics, elevations, footings,and foundations that exist in a process unit; used introubleshooting to quickly identify the primary flowpath and the control instrumentation being used inthe process.

Process instrumentation—transmitters, controll-ers, transducers, primary elements and sensors,and so on; all the measurement and control devicesused to monitor and control a process.

Process Instrumentation—course for study of theinstruments and instrument systems used in thechemical processing industry; includes terminology,primary variables, symbology, control loops, andbasic troubleshooting. The purpose of this class isto provide students with an understanding of the ba-sic instrumentation and modern process controlused in the chemical processing industry.

Process instruments—devices that controlprocesses and provide information about pressure,temperature, levels, flow, and analytical variables.

Process safety management (PSM) standard—governmentally set rules (a governmental processsafety management standard) designed to preventthe catastrophic release of toxic, hazardous, orflammable materials that could lead to a fire, explo-sion, or asphyxiation.

Process symbols—images that graphically depictprocess equipment, piping, and instrumentation.

Process technician—a person who operates andmaintains the complex equipment, systems, andtechnologies found in the chemical processingindustry. Process technicians have advanced train-ing in the equipment, technology, and scientific prin-ciples associated with modern manufacturing.Process technicians typically have college degreesand can be found operating and troubleshooting thecomplex systems found in the chemical processingindustry. Because these people work closely withspecific pieces of equipment or processes, they arecommonly called boiler operators, compressortechnicians, distillation technicians, refinery techni-cians, or wastewater operators.

Glossary

445

Process Technology—as defined in the regionallyaccredited process curriculum, course for study andapplication of the scientific principles (math, physics,chemistry) associated with the operation (instru-ments, equipment, systems, troubleshooting) andmaintenance (safety, quality) of the chemical processing industry.

Process Technology 1—Equipment—instructionin the use of common process equipment, includingbasic components and related scientific principles.Includes a study of valves, pipes and tanks, pumps,compressors, motors and turbines, heat exchang-ers, cooling towers, boilers, furnaces, distillationcolumns, reactors, and separators.

Process Technology 2—Systems—study ofcommon process systems found in the chemicalprocess industry, including related scientific princi-ples. Includes study of pump and compressor sys-tems, heat exchangers and cooling tower systems,boilers and furnace systems, distillation systems,reaction systems, utility system, separation sys-tems, plastics systems, instrument systems, watertreatment, and extraction systems. Computerconsole operation is often included in systemstraining. Emphasizes scale-up from laboratory(glassware) bench to pilot unit. Describe unitoperation concepts; solve elementary chemicalmass/energy balance problems; interpret analyti-cal data; and apply distillation, reaction, and fluidflow principles.

Process Technology 3—Operations—a college-level course, designed to be the capstone experience,that includes all the elements covered in a processtechnology two-year degree program. Combinesprocess systems into operational processes with em-phasis on operations under various conditions.Topicsinclude typical duties of an operator. Instruction fo-cuses on the principles of modern manufacturingtechnology and process equipment. Emphasizesscale-up from laboratory bench to pilot unit. Thepurpose of this class is to provide adult learners withthe opportunity to work in a self-directed work team,operate a complex operational system, collect and

analyze data, start and stop process equipment, fol-low and write operational procedures.

Process Troubleshooting—instruction in the differ-ent types of troubleshooting techniques, methods,and models used to solve process problems. Topicsinclude application of data collection and analysis,cause-effect relationships, and reasoning. Empha-sizes application of troubleshooting methods toscale-up from laboratory bench to pilot unit. Describeunit operation concepts; solve elementary chemicalmass/energy balance problems; interpret analyticaldata; and apply distillation and fluid flow principles.

Process variables—changeable conditions (vari-ables) that can be detected by instruments and thatprovide clues to what is occurring within the “big picture” of the entire process.

Products—manufactured materials made from re-actants combined in specific proportions.

Proportional band—on a controller, describes thescaling factor used to take a controller from 0% to100% output.

Proton—a positively charged particle in the nu-cleus of an atom.

PSM standard—see process safety manage-ment standard.

Pulp and paper industry—industry segment con-sisting of pulp and paper mills and convertingoperations. Pulp is made by chemically or mech-anically separating wood fibers from nonfibrousmaterial.

Pump-around system—consists of a series ofpiping, storage tank(s), valves, gauges, and apump.

Pumps—used primarily to move liquids from oneplace to another. Pumps come in two basic designs:(1) positive displacement (rotary and reciprocating),and (2) centrifugal.

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Glossary

Raffinate—the lighter material in the feedstock thatis free of the solute or material being dissolved;flows over the weir in the separator.

Range—the portion of the process controlled bythe controller. For example, the temperature rangefor a controller may be limited from 80�F to 140�F.

Rate (or derivative) mode—enhances controlleroutput by increasing the output in relationship to thechanging process variable. As the process variableapproaches the setpoint, the rate or derivative moderelaxes, providing a braking action that prevents over-shooting of the setpoint. The rate responds aggres-sively to rapid changes and passively to smallerchanges in the process variable.

RCRA—see Resource Conservation andRecovery Act.

Reactants—raw materials that are combined inspecific proportions to form finished products.

Reaction rate—the amount of time it takes a givenamount of reactants to form a product.

Reactor—device used to convert raw materials intouseful products through chemical reactions. It com-bines raw materials, heat, pressure, and catalysts inthe right proportions to initiate reactions and formproducts. Five reactor designs are commonly used:stirred, fixed-bed, fluidized-bed, tubular, and furnace.

Reboiler—a heat exchanger used to maintain theheat balance on a distillation tower.

Reformer—a reactor filled with a catalyst designedto break large molecules into smaller ones throughchemical reactions that remove hydrogen atoms.

Refrigeration system—used to provide cooling(e.g., air conditioning) to industrial applications.Refrigeration units are composed of a compressor(high-pressure refrigeration gas), heat exchanger–cooling tower combination, receiver, expansionvalve (low-pressure refrigeration liquid), and heat

exchanger (evaporator)–low-pressure refrigerantgas unit.

Regenerator—used to recycle or regenerate con-taminated catalyst.

Replacement reaction—a reaction designed tobreak a bond and form a new bond by replacing one or more of the components of the originalcompound.

Reset (or integral) mode—designed to reduce thedifference between the setpoint and process vari-able by adjusting the controller output continuouslyuntil the offset is eliminated. The reset or integralmode responds proportionally to the size of the er-ror, the length of time that it lasts, and the integralgain setting.

Resource Conservation and Recovery Act(RCRA)—federal law enacted in 1976 to protect hu-man health and the environment. A secondary goalis to conserve natural resources. It attains thesegoals by regulating all aspects of hazardous wastemanagement, including generation, storage, treat-ment, and disposal. This concept is referred to as“cradle to grave” management.

Respiratory protection—a standard or programdesigned to protect employees from airbornecontaminants.

Resume—a one-page document designed to sumup a job applicant’s skills, work history, hobbies,and education.

Run chart—a graphical record of a process vari-able measured over time.

Safety, Health, and Environment—course inwhich students gain knowledge and skills toreinforce the attitudes and behaviors required forsafe and environmentally sound work habits.Emphasizes safety, health, and environmental is-sues in the performance of all job tasks, and coversregulatory compliance issues.

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447

Saturated hydrocarbon—contains the maximumnumber of hydrogen atoms and contains single co-valent bonds. An unsaturated hydrocarbon can stillaccept an additional hydrogen atom.

Scatter plot—chart used to indicate relationshipsbetween two variables or pairs of data.

Science—a way of knowing and understanding theuniverse and the world we live in.The Latin word forscience is scire, which means “to know.”

Scientific method—the systematic process orframework by which science operates.

Scientific notation—see exponential notation.

Scrubber—device used to remove chemicals andsolids from process gases.

Secondary operational problems—issues cre-ated or responded to during a process upset otherthan the primary problem.

Separation system—designed to separate two liq-uids from each other by density differences; typi-cally, a solvent is introduced that will dissolve one ofthe components in the mixture, enhancing the sep-aration process. A separator has a shell, weir, vaporcavity, feed inlet, extract port and pump, and raffi-nate port and pump.

Sewage—water that contains 0.1% solid wastematter produced by human beings. Sewage is fre-quently referred to as wastewater. More than 80% ofthe sewage produced in the United States comesfrom industrial sources.

Sexual harassment—behavior that constitutes un-welcome sexual advances; could take the form ofverbal or physical abuse or unwelcome requests forsexual favors. The behavior may involve persons ofthe opposite sex or of the same sex; the offendingconduct may run from supervisor to employee,student to student, employee to employee, teacherto student, and so on. (For further information onsexual harassment, see Title VII of the Civil RightsAct of 1964.)

Solid waste—a by-product of modern technology;technically defined as a discarded solid, liquid, orcontainerized gas.This definition includes materialsthat have been recycled or abandoned throughdisposal, burning or incineration, accumulation,storage, or treatment.

Solute—material that is dissolved in liquid-liquidextraction; the material dissolved in a solution.

Solution—a homogenous mixture.

Solvent—chemical that will dissolve anotherchemical.

Span—the difference between the upper and lowerrange limits.

SPC—see statistical process control.

Specific gravity—a measurement of the heavinessof a fluid. Specific gravity equals the mass of a sub-stance divided by the mass of an equal volume ofwater.The specific gravity of gasoline is 6.15 lb/gal �8.33 � 0.738.

Statistical process control (SPC)—statistical con-trol methodology applied to a process.

Steam-generation system—a complex arrange-ment of boiler systems designed to convert water tosteam. These include pump-around systems, ad-vanced process control systems and instruments,fuel systems, and compressor systems.

Steam trap—a device used to remove condensatefrom steam systems.

Steam turbine—energy-conversion device thatconverts steam energy (kinetic energy) to usefulmechanical energy. Steam turbines come in two ba-sic designs: (1) condensing and (2) noncondensing.They are used as drivers to turn pumps, compres-sors, electric generators, and propeller shafts(e.g., on naval vessels).

Stirred reactor—typically includes a vessel, amixer, valves, piping, two or more inlet ports, and asingle outlet port. Reactors are complex analytical

448

Glossary

devices that have control features for a wide arrayof process variables and come in a variety ofshapes and designs.

Strainer—a device used to remove solids from aprocess before they can enter a pump anddamage it.

System—a collection of equipment designed to per-form a specific function (e.g., refrigeration system).

Tanks—vessels that store and contain fluids. Tankdesigns include spherical, open-top, floating-roof,drum, and closed styles.

Temperature—the hotness or coldness of asubstance.

Thermal cracking—process that uses heat andpressure to separate small hydrocarbons fromlarge ones.

Time management—a structured system thatarranges an individual’s study according to princi-ples governing use of time.

Toxic Substances Control Act of 1976 (TSCA)—federal legislation intended to protect human healthand the environment, and to regulate commerce byrequiring testing and imposing restrictions oncertain chemical substances. The TSCA applies toall manufacturers, exporters, importers, proces-sors, distributors, and disposers of chemical sub-stances in the United States.

Trainee—an unqualified technician recently as-signed to an operating unit.

Trainer—a qualified technician assigned to mentora trainee.

Troubleshooting methods—means of diagnosingprocess problems; include educational, instrumen-tal, experiential, and scientific.

Troubleshooting models—tools used to teachtroubleshooting techniques. Basic models includedistillation, reaction, and absorption and stripping,or combinations of these three.

TSCA—see Toxic Substances Control Act of1976.

U.S. chemical manufacturing industry—eco-nomic bloc that produced more than $460 billion ofexport goods in 2003.

Valve—a device designed to control (stop, start, ordirect) the flow of fluids.

Water permit—government-granted license issuedas part of efforts to control water pollution.

Water pollution—contamination of the water, es-pecially by industrial wastes.

Weight—the force of molecular gravitation.

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A

Abbott, William, 8

Abiogenic theory, 4

Absolute pressure (psia), 95

Absorbed heat, 88

Absorber columns, 226, 232, 376–377

AC (alternating current), 134–135, 323

ACB (Air Control Board), 335–336

Acids, 282, 291, 295–296

ACS (American Chemical Society), 29, 30–31

Activated charcoal, 233

Actuators, 202–203

Adhesion, 311

Adsorber, 226, 233

Air, density, 102

Air, respirators, 70, 79–80

Air bubbler systems, 171–172

Air Control Board (ACB), 335–336

Air-cooled heat exchangers, 146–147, 178–179

Airflow, 148, 178–179, 372

Air pollution, 334, 335–336

Air pressure, mechanical energy and, 202–203

Alcohols, 411–413

Alkalinity, 291, 295–296

Alkanes, 296–297, 396, 403, 408

Alkenes, 408–411

Alkylate, 300

Alkylation, 8, 248, 256–257, 300

Alkynes, 408–411

Allergic responses, 78

Alternating current (AC), 134–135, 323

Alternative fuel sources, 4, 16

American Chemical Society (ACS), 29, 30–31

American Petroleum Institute (API), 102

Ampere, 324

Analytical control loops, 186–191

Analytical variables, measures of, 173, 196–197

Anesthetic chemicals, 78

Aniline, 409

API gravity, 102, 306, 309

Archimedes’ principle, 308

Argicola, Georgius, 3

Argon, 315–316

Aromatic hydrocarbons, 251–252, 408

Asphalt, 9, 262, 298–300

Asphyxiation, 78

Associate of Applied Science degree, 44

Atmospheric pressure, 89–90, 306, 312–313

Atomic mass unit (amu), 282, 284, 288–291

Atomic number, 282, 284

Atoms, 282, 284

Automatic controls, 194, 195, 201

Automatic valves, 120–121, 202–203

Avogadro’s number, 397

Axial bearings, 136

Axial compressors, 130

Axial pumps, 124, 126

B

Backup systems, 356

Balanced equations, 282

Ball valves, 116–117, 118, 174

451

Barnsdall, William, 8

Barometer, 306, 312–313

Bases, 282, 291, 295–296

Batch process, 2, 8–9

Bauer, Georg, 3

Baumé gravity, 102, 306, 309

Bearings, 135–137

Bench-top operations, 276

Bennett Mechanical Comprehension Test (BMCT), 392

Benzene, 97, 251–252, 396, 408

Benzoic acid, 409

Bernoulli’s principle, 88, 101

Big Rollover, 2, 14–17

Biofuels, 4

Biogenic theory, 2, 3–4

Blinding permit, 81

Block-counting tests, 392

Blow molding, 236, 238–240

Boilers

defined, 142

downcomer tubes, 268

electrical systems and, 212–213, 230–231

overview, 103, 149–151

physics of, 323

reactions in, 292

steam-generation systems, 216–218, 423–424

symbols, 179–180

troubleshooting, 369–371, 372

Boiling point

chemical reactions and, 90–92, 292, 400

distillation systems, 229, 298–300

hydrocarbons, 296–298

Box furnaces, 153, 155

Boyle’s law, 88, 93, 98

Breakers, electrical, 189

British thermal units (BTUs), 99

Bromobenzene, 409

BTUs (British thermal units), 99

BTX aromatics, 252

Burton, William, 9

Burton Process, 9

Butane, 255, 296–297

Butterfly valves, 119, 174

Butylenes, 256–257

C

Cabin-fired heaters, 152, 153

CAER (Community Awareness and EmergencyResponse), 334, 338

Calendering, plastics, 236, 238–240

Calories, 99

Capillary action, 311

Carbon. See Hydrocarbons

Carbon dioxide, 208–212, 315–316

Carbon monoxide, 315–316

Carbon seals, 136

Carcinogens, 78

Cascade controls, 194, 201

Casting, plastics, 236, 238–240

Catalysts, 282

defined, 142

reactors, 155–156

regenerators, 257–258

types of, 292–293

Catalytic cracking (catcracking)

chemistry of, 282, 299–300

process development, 2, 8, 10–11

process of, 257–258

Catalytic reforming, 260, 261

Cause-and-effect (C&E) diagram, 342, 348–349

Cavitation, 125

Celcius (°C), 100, 170

Centrifugal compressors, 129–131, 177

Centrifugal pumps, 124, 125, 176

CERCLA (Comprehensive EnvironmentalCompensation and Liability Act), 338–339

Charcoal, 233

Charles’ law, 88, 98–99, 315

Check valves, 118, 174

Chemical bonding, 285

Chemical manufacturing, 419–420

452

Index

Chemical processing industry (CPI), 2

current trends and issues, 14–17

history of, 3–14

work environment, 37

Chemicals, hazardous, 77–78. See also HAZCOM(hazard communication standard);HAZWOPER (hazardous waste operationsand emergency response)

Chemistry, 42

alcohols, 411–413

alkenes, 408–411

alkynes, 408–411

aromatic hydrocarbons, 408

chemical bonds, 282, 400–403

definitions, 282

distillation, 298–300

education and training, 63–65

equations and periodic table, 286–291, 403–405

fundamental principles, 283–285, 396–399

hydrocarbons, 296–298

material balance, 293–294

organic, 396, 403

percent-by-weight solutions, 295

periodic table, 400–403

petroleum refining, 405–407

pH measurement, 295–296

reactions, 142, 156, 285

reaction types, 291–293

Chemists, 28

Chimney tower, 178

Chlorine, compression systems, 208–212,315–316

Chlorobenzene, 409

Classifier, 240

Clayton, John, 6

Clean Air Act (1972), 334, 335

Clean Water Act (1972), 334, 336

Coal, 4, 16

Cogeneration, 424

Cohesive force, 311–312

Coke deposits, 252

Cold work permit, 81

College programs, process technology, 20–24, 31

Combustible liquids, 77–78

Combustion reactions, 156, 282, 292

Community Awareness and Emergency Response (CAER), 334, 338

Community right-to-know, 334, 338–339

Compounds, chemical, 285, 399

Comprehensive Environmental Compensation andLiability Act (CERCLA), 338–339

Compressed-air systems, 228–234

Compressed gases, 77–78, 208–212

Compression molding, 236, 238–240

Compressors, 114, 129–131

physics of, 315–316, 325–327

refrigeration, 241–242

symbols, 176–177

troubleshooting, 365

Compressor systems, 208–212, 230–231

Computer software, 184, 361–362

Condensation, latent heat of, 99

Condensers, 146–147

Conduction, 99, 372

Conductivity probes, 171–172

Contact Engineer, 28

Control charts, 271–272, 273, 342, 346

Controllers, 194, 200–202

Control loops

automatic valves, 120–121

basic elements, 195

controllers and control modes, 200–202

defined, 194, 356

final control elements, 202–203

pressure, 235–236

process variables, 196–197

transmitters, 197–199

troubleshooting, 363

Control modes, 200–202

Control valves, 203

Convection, 99, 152–153, 371–373

Coolers, 146–147

Index

453

Cooling towers

defined, 142, 208

distillation systems, 228–234

overview, 147–149, 214, 216

symbols, 177–179

troubleshooting, 367, 369

utility systems, 243

Corrosive chemicals, 78

Counterflow, airflow, 148, 178

Covalent bonds, 282, 285, 396, 402

Cover letters, 387–390

Cracker feed, 262

Cracking processes, 8–9, 297

catalytic cracking, 2, 10–11

fluid catalytic cracking, 257–258

thermal cracking, 9, 10

Cross flow, airflow, 148, 178

Crude oil. See also Oil refining

batch processing, 8–9

biogenic theory, 3–4

chemical makeup, 296–298

consumption, 4


density, 309

distillation, 260, 262, 286

exploration and production, 418

Customer relationships, 344

Cycloalkanes, 396, 408, 410–411

Cyclones, 114, 123

Cylindrical-fired heaters, 152–153, 154

D

Dalton’s law, 9, 88, 96–97, 396, 406–407

Data collection/analysis

pilot plant, 271, 272

quality control, 275–276, 344–352

safety, 63

types of, 342

DC (direct current), 134–135, 323

DCS (distributive control system), 184, 200–201, 202

Decane, 296–297

Demineralizers, 114, 123, 226, 242–243

Density, 101–102, 306, 308–312

Department of Transportation (DOT). See DOT(Department of Transportation)

Derivative mode, controllers, 194, 201

Diagrams

overview, 173–174

piping and instrumentation drawings (P&ID),183–184, 186–191

process flow diagrams (PFDs), 182–184

process symbols, 175–182

Diaphragm actuator, 202–203

Diaphragm valve, 119

Diaphragm valves, 174

Diesel, 262

distillation of, 298–300

Diesel engines, 424

Differential pressure (DP), 196–197


Differential pressure transmitters, 171–172

Direct current (DC), 134–135, 323

Direct-fired furnaces, 152–154

Discharge pressure, 125

Displacement, 308

Displacement devices, 171–172

Distillate, 157

Distillation, 157–160, 232, 396

chemistry of, 298–300

crude oil, 286

petroleum, 405–407

pilot plant operation, 266–272

symbols, 180, 181

troubleshooting, 377–379, 379–381

Distillation column, 157–160, 180, 181

defined, 142

packed, 226

pilot plant operation, 268–269

plate, 226

reactor systems, 228

troubleshooting, 376–377

454

Index

Distillation columns

crude distillate, 261

Distillation process, 4, 57, 58

Dalton’s law, 96–97

Distillation system, 146–147

Distillation systems

overview, 228–234

Distillation towers, 103

alkylation, 257

chemistry in, 299

defined, 248

Distributive control system (DCS), 184, 200–201, 202

Diversity training, 2, 25

Documentation

HAZCOM, 74–77

DOT (Department of Transportation)

labeling, 84, 85

overview, 36, 70

warning labels, 77

Double-pipe heat exchangers, 143–147

Downcomer tubes, boilers, 151, 268

Drafts, airflow, 148, 178

Drake, Edwin, 7

Drilling rigs, 422

Ductility, 311

Dynamic compressors, 129–131, 315–316

E

Education and training, 17–24

ACS standards, 31–32

chemistry and physics, 63–65

instrumentation and process control, 51–53

job search, 386–397

math, 65–66

process equipment, 53–54

process operations, 57–60

process systems, 55–57

process technology programs, 43–47

quality control principles, 50–51

safety, health and environment, 47–50

statistics, 63


Efficiency curves, 125

Effluent, 424–426

Elasticity, 310

Electrical breakers, 189

Electrical drawings, 168, 188–189, 190

Electrical systems, 208, 212–213, 230–231

Electricians, 28

Electricity, 134–135

generation of, 212–213, 325–327, 423–424

physics of, 323–328

thermocouples, 170

utility systems, 243

Electronic controllers, 200–202

Electronic transmitters, 197–199

Electrons, 282, 284, 402

Elements, chemical, 282, 284, 288–291, 399

Elements, control loops, 197, 198

Elevation drawings, 168, 188

Emergency response, 70, 80–83, 334, 338

Employee training, 74–77, 274–275

Employment in chemical processing

ACS hiring standards, 31


job search, 386–393

overview, 24–29

preemployment testing, 392

Endothermic reactions, 156, 282, 291

Energy

defined, 306

fluid energy conversions, 103

isolation procedure, 81

liquid, 102

mechanical, 202–203

rotational, 210–212, 325–327

Engineers, 28

Enriching, 268

Entry permit, 81

Environmental hazards, 47–50, 71–72

Index

455

Environmental Protection Agency (EPA), 36,49–50, 71–72, 334, 335–336

Environmental quality, 233

Environmental standards

air pollution control, 335–336

community right-to-know, 338–339

emergency response, 338

solid waste control, 336–337

toxic substances, 337

water pollution, 336

EPA (Environmental Protection Agency), 36,49–50, 71–72, 334, 335–336

Equipment


failure, 356

operating procedures, 276, 278

safety training, 47–50

troubleshooting, 60–63, 356, 360

Equipment location drawings, 168, 189, 191

Estimated ultimately recoverable (EUR) oil, 2, 15

Ethane, 296–297

Ethanol, 413

Ethers, 255

Ethylbenzene, 253, 409

Ethylene, 255, 256

Ethylene glycols, 253, 254, 413

Evaporation, cooling towers, 148

Exothermic reactions, 156, 282, 291

Expansion valve, 241

Experimentation, planned, 342, 350–351

Explosive materials, 77–78

Exponential notation, 396, 398

Extraction, separators, 161, 234–235, 379–381

Extracts, 161, 226, 234–235, 379

Extrusion, 226, 236, 238–240

F

Fahrenheit (°F), 100, 170

Fail open/fail closed, 356

Feed systems, 161, 230–231, 266, 267, 269–271

Filters, 114, 122–123

Fin fans, 146–147, 178–179

Fire control, 49–50, 72, 82

Fired heaters (furnaces)

control loops, 196

distillation systems, 230–231, 261

energy conversion, 103

overview, 151–154, 155

reactions in, 292

symbols, 179–180


Fired heater systems, 208, 218–221

Fire extinguishers, 82

Fire prevention, 49–50, 72

Fire protection, 49–50, 72

Fire-tube boilers, 150, 179–180

Fire-tube heaters, 142

First responder, 70, 81

Fishbone diagram, 342, 348–349

Fittings, pipes, 121–123

Fixed-bed reactors, 154–157, 181–182, 227–228,248, 253

Fixed-head heat exchangers, 143–147

Fixed platforms, drilling rigs, 422–423

Flammable gases, 77–78

Flammable liquids, 77–78

Flare system, 226, 236–237

Flash gas, 262

Floating-head, multipass (U-tube), 143–147

Floats, 171–172

Flow. See also Fluid flow

control loops, 196–197

data collection, 275–276

rate calculations, 103, 172–173, 314

symbols, 177–179

Flowcharts, 342, 346, 348

Flow diagrams, 168, 186–191

Flow of solids, 103

Fluid catalytic cracking, 248, 257–258

Fluid coking, 248, 260

Fluid energy conversions, 103

456

Index

Fluid flow, 88, 100–103

cabin-fired heaters, 152

defined, 142


Fluidized-bed reactors, 154–157, 181–182,227–228, 248, 252

Fluids. See also Fluid flow

pressure in, 312–319

specific gravity, 308–312

Food and beverage processing, 418, 427

Force, 313–314, 319–323

Formula weights, 397

Foundation drawings, 168, 188

Foundations for Excellence in the ChemicalProcess Industries (ACS, 1994), 30–31, 32

Fractional distillation, 2, 9–10, 13, 257–258, 283,298–300

Frequency plots, 342

Friction, 135–137

Fuel heat values, 220–221

Furnace reactors, 154–157, 181–182

reactions in, 292

Furnaces

control loops, 196

distillation systems, 230–231, 261

energy conversion, 103

overview, 151–154, 155

reactions in, 192

symbols, 179–180


Furnace systems, 218–221

defined, 208

Fuses, 189

Fusion

latent heat of, 99

G

Gases

Charles’ law, 88, 98–99

compressed, 77–78

compressor systems, 208–212, 315–316

flammable, 77–78

ideal gas law, 88, 98–99

Noble, 400

pressure, 89–90, 95–99

Gas generator, 211

Gas oils, 262

Gasoline

batch processing, 8

cracking, 300

density, 309


olefins, 255

specific gravity, 102

Gas turbines, 133–134, 210–212, 424

Gate valves, 116, 174

Gauge pressure (psig), 95

Generators, electric, 325–327

Gesner, Abraham, 6

Globe valves, 116

Glove valves, 174, 203

Gold, Thomas, 4

Gold collar, 2, 29

Governor valves, 132

Gravitational force, 307

H

Hair-pin heat exchanger, 143–147

Hand tools, 114–115

Hardness, 310

Hardwire interlocks, 184

Hart, William Aaron, 6

Hazard communication standard. See HAZCOM(hazard communication standard)

Hazardous chemicals, 77–78. See also HAZCOM(hazard communication standard);HAZWOPER (hazardous waste operationsand emergency response)

Hazardous chemicals, safety of, 77–78

Hazardous Materials Identification System(HMIS), 77

Hazardous waste operations, 82–83

HAZCOM (hazard communication standard),49–50, 70, 72, 74–77, 338

Index

457

HAZWOPER (hazardous waste operations andemergency response), 70, 82–83

Health hazards

chemical, 78


overview, 71–72

Hearing conservation program (HCP), 83

Heat. See also Heat transfer

chemical reactions and, 292

defined, 142


rate, calculating, 327

thermocouples, 170

Heaters. See Fired heaters (furnaces)

Heat exchangers

distillations, 230–231

physics of, 317–319, 327–328

refrigeration, 241–242

symbols, 177–179

troubleshooting, 365–367, 368

Heat exchanger systems, 56–57, 142–147, 208,214–216

Heating oil, 298–300

Heat transfer, 56–57, 88

convective, 152–153

defined, 142

heat exchangers, 143–147

physics of, 99–100, 317–319

Heat values, fuel, 220–221

Helium, 315–316

Heptane, 296–297

Hexane, 296–297, 299–300

Hexene, 299–300

High-pressure (HP) steam, 217

Histograms, 342, 351

History

chemical processing industry, 3–14

distillation systems, 230

industrial processes, 248–251

HMIS (Hazardous Materials Identification System), 77

Hooke’s law, 310

Horsepower (HP), 327

Hot work permit, 81

Houdry process, 10–11

HP (high-pressure) steam, 217

HP (horsepower), 327

Hubbert peak theory, 2, 14–17

Hydraulically operated actuator, 203

Hydraulic systems, 213–214

Hydrocarbons

aromatic, 408

chains, 402

chemistry of, 296–298

compression of, 315–316

defined, 283

distillation fractions, 298–300

saturated, 396, 410


Hydrocrackate, 300

Hydrocracking, 248, 259–260, 300

Hydrodesulfurization, 248, 258–259

Hydrogen

acid-base reactions, 291

compressor systems, 208–212, 315–316

in crude oil, 4

defined, 283

pH measurement, 295–296

Hydrogen fuel cells, 4

Hydrostatic pressure, 90

Hydroxyl ion, 283, 291

I

Ideal gas law, 88, 98–99, 315

Improvement cycles, 342

Inclined planes, 320

Industrial fires, 49–50, 72, 82

Industrial hygienist, 28

Industrial noise, 83

Industrial processes

chemical manufacturing, 419–420

development of, 248–251

food and beverage industry, 427

458

Index

mining and mineral processes, 426–427

oil and natural gas exploration and production,420–423

overview, 418–419

petrochemical, 251–256

petroleum refining, 256–262, 419–420

pharmaceutical manufacturing, 428–430

power generation, 423–424

pulp and paper processing, 430–431

water and wastewater treatment, 424–426

Inert gases, 400

Inertia, 306, 307

Injection molding, 236, 238–240

Inner transition elements, 400

Instrumentation

distillation systems, 228–234


piping and instrumentation drawings (P&ID), 168,183–184, 186–191

process control, 272, 274

separator systems, 235

symbols, 184, 185

Instrument technicians, 28

Integral mode, controllers, 194, 201

Interlocks, 184

Internal slip, 125

Interviews, employment, 388–391

Ionic bonds, 282, 285, 396, 403

Ions, 283, 285

Irritants, 78

Isobutane, 256–257, 300

Isopropyl alcohol, 413

J

Jackup platforms, 422–423

Jet fuel, 298–300

Jet pump systems, 125

Jobs. See Employment in chemical processing

K

Kelvin (K), 100, 170

Kerosene, 262

batch processing, 8

catalytic cracking, 299–300


Kettle reboiler heat exchangers, 143–147,178–179

Kier, Samuel, 6–7

Kinetic energy, 306

L

Labels

DOT, 77, 84, 85

HAZCOM, 76

warning, 49–50

Lab technician, 28

Labyrinth seals, 136

Laminar flow, 102

Laminating, plastics, 236, 238–240

Latent heat, 99

Layer out process, 226, 235

Legislation. See also Environmental standards

air pollution control, 335–336

community right-to-know, 338–339

emergency response, 338

safety, 71–74

solid waste control, 336–337

toxic substances, 337

water pollution, 336

Level measurements, 171–172



piping and instrumentation drawings (P&ID),186–191

Liability. See Environmental standards

Lift check valve, 118

Liquid energy, 102

Liquid-liquid extraction process, 161, 235,379–381

Liquids

pressure, 88, 89–90, 93, 95

Liquids, flammable, 77–78

Litmus paper, 295–296

Lobe pumps, 127

Index

459

Lock-out/tab-out procedure, 70, 81, 189

Logic controllers, programmable, 202

LP (low-pressure) steam, 217

Lubricating oil, distillation of, 298–300

Lubrication systems, 114, 135–137, 213

Lukasiewicz, Ignacy, 7

Lummus method, 256

M

Machines, 319–323

Machinists, 28

Malleability, 311

Manual controls, 194, 201

Manufacturer’s information, 49–50

Mass, 306, 307

Material balancing, 283

Material safety data sheets. See MSDS (materialsafety data sheets)

Math, applied, 42, 65–66, 104–109

Matter, 306

MCC (motor control center), 189, 212–213

Mechanical advantage, 320

Mechanical craftsmen, 28

Mechanical drafts, airflow, 148

Mechanical energy, 202–203

Mechanical seals, 136–137

Mechanical steam traps, 138

Medium-pressure (MP) steam, 217

Melting point, 400

Mendeleev, Dmitri, 396, 400

Mercury, 311

Metalloids, 400

Metals, 400

Methane, 296–297

Methanol, 255, 413

Mineral ions, 291

Mineral processing, 418, 426–427

Mining, 418, 426–427

Mixtures, 283, 285

Mole, 396, 397

Molecules, 283, 285. See also Chemistry

Moments and levers, principle of, 321–323

Motor control center (MCC), 189, 212–213

Motor-driven actuators, 203

Motors, 134–135, 177

MP (medium-pressure) steam, 217

MSDS (material safety data sheets), 49–50,76–77, 79, 338

Mud drums, boilers, 151

Multiple-variable process model, 62

Murdock, William, 6

Mutagens, 78

N

Naphtha, 8, 262

National Fire Protection Association (NFPA), 77

National Institute for Occupational Safety andHealth (NIOSH), 37, 73–74

Natural drafts, airflow, 148

Natural gas

biogenic theory, 3–4

chemical makeup, 296

compression, 315–316

conversion to oil, 5

exploration and production, 418, 420–423

heat value, 220–221

olefins, 255

Neurotoxins, 78

Neutralization reactions, 283, 291

Neutrons, 283, 284

NFPA (National Fire Protection Association), 77

NIOSH (National Institute for Occupational Safetyand Health), 37, 73–74

Nitrobenzene, 409

Nitrogen, 4, 208–212, 315–316

Noble gases, 400

Noise, 83

Nonane, 296–297

Nonmetals, 400

NRC (Nuclear Regulatory Commission), 34–36

Nuclear reactors, 4, 34–36, 154–157, 181–182,418, 424

Nuclear Regulatory Commission (NRC), 34–36

460

Index

O

Occupational Safety and Health Administration(OSHA), 37, 42, 49–50, 71–74, 338

Occupational Safety and Health Review Commis-sion (OSHRC), 37, 72–74

Occupations. See Employment in chemical processing

Octane, 296–297

Offshore drilling, 4–5, 422–423

Ohm’s law, 323–324

Oil


exploration and production, 420–423

refining, distillation, 405–407, 419–420

refining, history, 3–14

Oil Depletion Analysis Centre, 15

Oil shale, 4, 16

Olefins, 255, 256–257, 296–298, 300, 409

Opening/blinding permit, 81

Operations, equipment


procedures, 276, 278

safety training, 47–50

troubleshooting, 356, 360

Operations, process, 57–60

Organic chemistry, 396, 403

Organic peroxide, 77–78

Orifice plates, 173, 196

OSHA (Occupational Safety and Health Adminis-tration), 37, 42, 49–50, 71–74, 338

OSHRC (Occupational Safety and Health ReviewCommission), 37, 72–74

Overhead systems, 269

Oxidizers, 78

Oxygen, 4

P

Packed distillation column, 158–160, 180, 181,226, 232

Paper industry, 418

Paraffin, 298–300

Paraxylenes, 255

Pareto chart, 342, 350

Pascal’s law, 89, 93

PD (positive displacement) pumps, 124, 126–128, 176

PD (proportional plus derivative) controllers, 194, 201

Pentane, 296–297

Pentylenes, 256–257

Percent-by-weight, 283

Periodic table, 283, 284, 286–291, 400–403

Permissives, 184

Permit systems, 70, 81, 274

air permits, 335–336

overview, 72

water, 334, 336

Permit to enter, 81

Peroxide, 77–78

Personal protective equipment (PPE), 70, 80, 81

Petrochemical processes, 251–256

Petroleum. See also oil

overview, 3–4

products from, 4–6

refining, distillation, 405–407, 419–420

PFD (process flow diagrams), 168, 173–174,182–184, 356

pH, 283, 295–296

Pharmaceutical industry, 418, 428–430

Phenol, 409, 411–413

Physical hazards, 49–50, 70, 77–78

Physics


electricity, 323–328

fundamental concepts, 306–308

machines, complex and simple, 319–323

pressure in fluids, 312–319

P&ID (piping and instrumentation drawings), 168,173–175, 183–184, 186–191

PID (proportional-integral-derivative) controllers,194, 201

Pilot plant operation, 266–276

Pipe-coil heat exchangers, 143–147

Index

461

Pipes/piping, 114, 121–123, 173–175. See alsoPiping and instrumentation drawings (P&ID)

Piping and instrumentation drawings (P&ID), 168,173–175, 183–184, 186–191

PI (proportional plus integral) controllers, 194, 201

Piston actuator, 203

Piston compressor, 131

Planned experimentation, 342, 350–351

Plant permit system, 81

Plastics system, 236, 238–240

Plate-and-frame heat exchangers, 178–179

Plate distillation

absorption, 232

defined, 226

overview, 158

symbols for, 180, 181


Platform, drilling rigs, 422–423

Plug valves, 117, 174

Pneumatic actuators, 202–203

Pneumatic controllers, 200–202

Pneumatic transmitters, 197–199

Pollution control. See Environmental standards

Polyethylene, 255, 256

Polymerization, 8, 239

Porosity, 307

Positive displacement compressors, 130–131,177, 315–316

Positive displacement pumps, 124, 126–128, 176

Potential energy, 306

Power generation, 418, 423–424

Power transformation, 418, 423–424

PPE (personal protective equipment), 49–50, 70,80, 81

P (proportional) controller, 194

Preheat systems, 228–234, 267

Pressure

absolute, 95

boiling point and, 90–92

Boyle’s law, 88, 93, 98

Charles’ law, 88, 98–99

chemical reactions and, 292


conversion to mechanical energy, 202–203

Dalton’s law, 88, 96–97, 396, 406–407


differential pressure transmitters, 171–172

discharge, 125

in fluids, 312–319

gases, 89–90, 95–99

gauges and instruments, 95169

ideal gas law, 88, 98–99

liquid pressure, 88, 89–90, 95

overview, 89–90

Pascal’s law, 89, 93


problems, 93–95

relief systems, 150

steam, 217

suction, 125

temperature and, 314–319


vacuum, 92–93, 95

Pressure relief system, 226, 235–236

Primary operational problems, 356, 360

Principle of moments and levers, 321–323

Procedures, operating, 276, 278

Process, defined, 42

Process diagrams. See Process flow diagrams(PFDs)

Process flow diagrams (PFDs), 168, 173–174,182–184, 356

Process heaters, 371–373

Process instrumentation

defined, 266

definition, 42

distillation, 272, 274

level measurements, 171–172

overview, 51–53, 168

pressure, 169, 171–172, 186–191

symbols, 173–174, 185–187

temperature, 170


462

Index

Process legend, 183, 186–187

Process operations, 57–60

Process Safety Management (PSM) standard, 43,49–50, 70–72, 74

Process symbols, 168. See also Piping and instru-mentation drawings (P&ID); Process flow diagrams (PFD)

boiler and furnace systems, 179–180

compressors and pumps, 176–177


heat exchangers and cooling towers, 177–179

instruments, 185–187

overview, 173–174

piping, 175

pumps and tank systems, 175–176

reactors, 180–182

Process technician

careers in, overview, 24–29, 31

defined, 3, 42


job description, 27

roles and responsibilities, 29–34

Process technology

defined, 3, 42


Process variables, 196–197, 356. See also Qualitycontrol

Product directives, 345

Products, chemical reactions, 287

Product storage systems, 228–234

Product variation, 271, 344–346. See also Qualitycontrol

Programmable logic controllers, 202

Propane, 296–297

Proportional band, controllers, 194, 201

Proportional-integral-derivative (PID) controllers,194, 201

Proportional (P) controllers, 194

Proportional plus derivative (PD) controllers, 194, 201

Proportional plus integral (PI) controllers, 194, 201

Propylene, 255, 256–257

Protective equipment, 49–50, 70, 80, 81

Protons, 284

psia (absolute pressure), 95, 169

psig (gauge pressure), 95, 169, 217

PSM standard (Process Safety Management), 43,49–50, 70, 71–72, 74

Pulp and paper industry, 418

Pump-and-feed systems, 228–234

Pump-around systems, 208, 209

Pump curve, 125

Pumps, 114, 124–129


symbols, 175–177


Pyrophoric, 78

Q

Quality control

cause-and-effect (C&E) diagrams, 342, 348–349

data collection forms, 351


flowcharts, 346, 348

histograms, 351

improvement cycle, 343

Pareto chart, 350

pilot distillation plant, 274–276

planned experimentation, 342, 350–351

principles of, 42, 342–343

run charts, 342, 348

scatter plots, 342, 352

statistical process control (SPC), 342, 344–346

supplier-customer relationships, 344

tools, 344

waste management, 338–339

R

Radial bearings, 136

Radiant heat transfer, 152–153, 371–373

Radiation, 99

Radiation level detectors, 171–172

Raffinate, extractions, 161, 226, 234–235, 379

Range, 194

Index

463

Rankine (°R), 100, 170

Raoult’s law, 9

Rate mode, controllers, 194, 201

Raw materials, 219, 345

RCRA (Resource Conservation and RecoveryAct), 334, 337

Reactants, 283, 287, 293–294, 397

Reaction rate, 155–156, 283, 292

Reaction variables, 374

Reactors, 154–157

BTX aromatics, 252

chemistry in, 299

defined, 142, 248

fluid catalytic cracking, 257–258

nuclear, 4, 34–36, 154–157, 181–182, 418, 424

overview, 59

symbols, 180–182

systems, 227–228


Reading comprehension tests, 392

Reboiler, distillation, 157–158, 230, 248, 268, 299

Reciprocating compressors, 130–131

Reciprocating pumps, 127

Rectifying, 268

Redundancy, 356

Refining processes, 8–9, 249–250, 256–262,419–420

Reflux, 157–160, 268

Reformer, 248, 255

Refrigeration systems, 226, 241–242

Regenerators, 248, 252

Regulations. See Legislation

Regulatory agencies, 34–37

Relief valves, 119, 174

Remote controlled valves, 202–203

Replacement reactions, 283, 291

Representative elements, 400

Reproductive toxins, 78

Research technician, 27

Reset mode, controllers, 194, 201

Residue, distillation, 157

Residuum, batch processing, 8

Resins, 291

Resistance, electrical, 323–324

Resource Conservation and Recovery Act (RCRA), 334, 337

Respiratory protection, 70, 79–80

Resume, 387–390

Reynold’s number, 101

Riser tubes, boilers, 151

Rotameters, 173

Rotary compressors, 130–131

Rotary pumps, 126–127

Rotational energy, 210–212, 325–327

Rotor, 132

Run chart, 342, 348

S

Safety

basic principles, 72–73

cooling towers, 369


electrical drawings, 189

hazardous chemicals, 77–78

interlocks and permissives, 184

overview, 71–72

pilot distillation plant, 274–276

pressure relief, 150, 226, 235–236

Safety valves, 119–120, 150, 174

Salaries, 27–29

Samples, quality control, 345

Saturated hydrocarbons, 396, 410

Scatter plots, 342, 352

Scientific method, 397

Scientific notation, 396, 398

Scrubbers, 227, 233

Seals, 135–137

Secondary operational problems, 356, 360

Sensible heat, 99, 147–148

Sensitizers, 78

Sensors, control loops, 197

Separation systems, 161, 227, 234–235, 379–381

464

Index

Sewage treatment, 418, 424–426

Shale, 4, 16

Shell-and-tube condensers, 299

Shell-and-tube heat exchangers, 143–147,178–179, 365–367, 368

Shell heat exchangers, 143–147

SHP (super-high-pressure) steam, 217

Shutdown items, 184, 276, 278

Sight glasses, 171–172

Sillman, Benjamin Jr., 7

Simulations, 361–362

Single-pass heat exchangers, 143–147

Sliding vane pumps, 127

Smart transmitters, 199

Software, simulations, 361–362

Softwire interlocks, 184

Solenoid valves, 203

Solids, 103, 239–240

Solid waste, 334, 336–337

Solutes, 161, 227, 235

Solutions, 285

Solvay, Ernest, 9

Solvents, 161, 227, 235

Sour feed, 258

SPC (statistical process control), 50, 63, 342,344–346

Specifications, product, 271

Specific gravity, 102, 306, 308–312

Specific heat, 99

Specific weight, 308–312

Spiral heat exchangers, 178–179

Spring valves, 203

Start-up items, 184, 201, 276, 278

Statistical process control (SPC), 50, 63, 275, 342,344–346

Steam generation systems, 149–151, 208,216–218, 228–234, 323, 423–424

Steam traps, 114, 137–138, 217

Steam turbines, 103, 114, 132, 424

electrical systems and, 212–213


symbols, 177

Stirred reactors, 154–157, 156, 227–228

Stirred-tank reactors, 181–182

Stop check valve, 118–119

Storage

hazardous chemicals, 77–78

symbols, 175–176

tanks, 121–123

Straight-through diaphragm valve, 119

Strain, 310

Strainers, 114, 123

Streamline flow, 102

Stripping columns, 232, 268, 376–377

Suction pressure, 125

Sulfur, crude oil, 4

Superfund Amendments and Reauthorization Act, 338

Superheating, steam, 371

Super-high-pressure steam (SHP), 217

Supplier-customer relationships, 344

Surface tension, 311

Swing check valves, 118

Symbols, process, 168. See also Piping and instrumentation drawings (P&ID); Processflow diagrams (PFD)

boiler and furnace systems, 179–180

compressors and pumps, 176–177


heat exchangers and cooling towers, 177–179

instruments, 185–187

overview, 173–174

piping, 175

pumps and tank systems, 175–176

reactors, 180–182

Syn-gas, 6, 16

Synthetic resins, 238

T

Tag-out procedures, 70, 81

Tanks, storage, 114, 121–123, 175–176

Tar, 298–300

Target organ effects, 78

Tar sands, 4, 16

Index

465

Temperature

cohesive force and, 311–312



distillation systems, 230, 268

gauges and instruments, 170



pressure and, 314–319

Tenacity, 310

Tensile strength, 310

Tension-leg platforms, 423

Teratogens, 78

Test of Chemical Comprehension, 392

Thermal cracking, 3, 8, 9, 10

Thermal efficiency, 327–328

Thermal expansion, 317–319

Thermocouples, 170

Thermostatic traps, 138

Thermosyphon reboiler, 143–147, 362–363

Three-phase motor, 135

Toluene, 251–252, 409

Tools

hand tools, 114–115

quality control, 344–352

Toxic chemicals, 78, 334, 337

Toxicology, 49–50, 79

Toxic Substances Control Act (1976), 334, 337

Training programs, 17–24

ACS standards, 31

HAZCOM, 74–77

safety, 274–275

Transformers, 189

Transition elements, 400

Transmitters, control loops, 197–199

Transportation, hazardous chemicals, 77–78

Troubleshooting

absorption and stripping model, 376–377

boiler model, 369–371, 372

compressor model, 365

cooling tower model, 367, 369

distillation model, 377–379

education and training for, 60–63

equipment, 362

furnaces, 221, 371–373

heat exchanger model, 365–367, 368

instrumentation, 362–363

methods, 356–360

models, 360–362

multivariable model, 381, 382

pump model, 363–364

reactor model, 374–376

separation model, 379–381

TSCA (Toxic Substances Control Act 1976), 334, 337

Tubular reactors, 154–157, 181–182, 227–228

Tuning controllers, 202

Turbines, 114, 132, 133–134, 424

Turbine systems, 210–212

Turbulent flow, 102

U

Ultrasonic level detectors, 171–172

Unplugging permit, 81

Unsaturated hydrocarbons, 410

Unstable chemicals, 78

Utility systems, 243

U-tube heat exchangers, 143–147, 178–179

V

Vacuum, pressure (psiv), 92–93, 95, 317–319

Valence electrons, 284–285

Valves, 114

automatic, 203

control, 203

expansion, 241

governor, 132

pressure relief, boilers, 150

pressure relief systems, 235–236

symbols, 174

types of, 115–121

466

Index

Vane actuator, 203

van Helmont, Jan Baptista, 6

Vaporization

distillation, 157–160, 299

heat exchanger, 146–147

latent heat, 99

Vapor lock, 125

Vapor pressure, 90–92, 97, 406–407

Vapors, compression and, 315–316

Variation, product, 271, 344–346. See also Qualitycontrol

Venturi flow nozzles, 173

Viscosity, 101, 309–310

Voltage, 134–135, 324

Voltmeters, 189

Volume, 307

Volute, 124

W

Wages, chemical processing industry, 27–29

Warning labels

DOT, 77, 84, 85

HAZCOM, 76

overview, 49–50

Waste management, 338–339

Water

density, 102, 309

permits, 334, 336

pollution, 334, 336

sources of, 122–123


treatment of, 242–243

Water hammer, 137–138

Water reactive chemicals, 78

Water treatment systems, 242–243, 424–426

Water-tube boilers, 150–151, 179–180

Water turbines, 424

Weight, defined, 306

Weight-operated valves, 203

Weir diaphragm valve, 119

Wetting, 311

Wind power, 4, 424

Work, physics, 319–323

Work teams, 278

X

Xylenes, 251–255

Y

Young, James, 6–7

Index

467

introduction to process technology

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