Welcome to Process Operations EDT 2213

Welcome to Process Operations EDT 2213Zin Eddine DadachChemical Engineering Department Higher Colleges of Technology2014-2015

Chemical Engineering Chemical engineering essentially deals with the engineering of chemicals, energy and the processes that create and/or convert them. Modern chemical engineers are concerned with processes that convert raw materials or (cheap) chemicals into more useful or valuable forms.

Job opportunities for Chemical EngineersChemical engineering are employed across a huge variety of sector including:

Chemical and allied productsPharmaceuticalsEnergyWaterFood & drinkOil & gasProcess plants & equipmentBiotechnologyBusiness and managementConsultancy

Chemical engineer dutiesChemical engineers utilize mass, momentum, and energy transfer along with thermodynamics and chemical kinetics to analyze and improve on "unit operations in a chemical plant."

Introduces basic chemical engineering unit operations. Three main areas of unit operations are covered: Fluid flow, heat transfer and mass transfer. The principles of operation of major equipment and machinery often found in the chemical process industries are presented. Fundamental engineering calculations are introduced, and laboratory work is used to reinforce the understanding of certain chemical engineering phenomena.Objective of the course

CLO 1- Explain the meaning of unit operations and identify the various unit operations found in the plant CLO 2- Explain the importance of piping systems, fittings and devices used for metering of fluids CLO 3- Describe the various types of machinery to move fluids CLO 4- Discuss the principles of operation of fired heaters and heat exchange equipment CLO 5- Discuss the principles of separation processes and their equipment LEARNING OUTCOMES

Introduction to the course. Many examples are to be given to the students as well as relevant articles on the subject.

SO1: Explain the meaning of unit operationsSO2: List the unit operations most likely found in the plant

If the schedule permits, a site visit to a chemical industry will complement this learning outcome

L.O #1

ABU DHABI REFINERY

An oil refinery or petroleum refinery is an industrial process plant where crude oil is processed and refined into more useful products such as petroleum naphtha, gasoline, diesel fuel, asphalt base, heating oil, kerosene and liquefied petroleum gas.OBJECTIVE OF OIL REFINERY

Petroleum products are grouped into three categories: light distillates, middle distillates and heavy distillates. LIGHT DISTILLATES: Liquefied petroleum gas (LPG), Gasoline (also known as petrol, Naphtha MIDDLE DISTILLATES: Kerosene and related jet aircraft fuels, Diesel fuel HEAVY DISTILLATESFuel oils, Lubricating oils, Paraffin wax, Asphalt and tar, Petroleum coke

MAJOR PRODUCTS

LISTEN...LEARN...THINK...GROW11MAIN REFINERY PRODUCTS

Pretreatment: Desalting before entering the refinery to avoid corrosion problems: Preheating of crude oil for separation by distillation Separation of crude oil into fractions by atmospheric and vacuum distillation. Chemical transformation

COMMON PROCESS UNITS FOUND IN A REFINERY

Step #1:Crude Oil Pretreatment Desalter to remove the impurities : salt, water, solids, ....

A desalter is a process unit in an oil refinery that removes salt from the crude oil. The salt is dissolved in the water in the crude oil, not in the crude oil itself. The desalting is usually the first process in crude oil refining. The salt content after the desalter is usually measured in PTB - pounds of salt per thousand barrels of crude oil.

Usually desalting is necessary only when the salt content of a crude oil is greater than 10 lb/ 1000bbl (expressed as NaCl)

But now almost all crude oils are desalted to increase the efficiency of the refineriesLISTEN...LEARN...THINK...GROW14CRUDE OIL DESALTING

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LISTEN...LEARN...THINK...GROW15Electrostatic De-salter

Steps #2Preheating & Vaporization of crude oil Furnace

Following the desalter, the crude oil is further heated by exchanging heat with some of the hot, distilled fractions and other streams. It is then heated in a fuel-fired furnace (fired heater) to a temperature of about 398 C and routed into the bottom of the first distillation unit.

LISTEN...LEARN...THINK...GROW17

PREHEATING CRUDE OIL

FURNACE One of the major energy demands within refineries comes from the need to heat the crude feedstock upstream of the crude distillation column to obtain the desired flash and distillation yields.

Step #3: Distillation Distillation Columns

STEP III: ATMOSPHERIC AND VACCUM DISTILLATIONThe crude atmospheric and vacuum distillations are the rst major processing units in any renery. They are used to separate the crude oils into fractions according to boiling point so that each of the processing units following will have feedstock that meet their particular specications. Higher efciencies and lower costs are achieved if the crude oil separation is accomplished in two steps: First by fractionating the total crude oil at essentially atmospheric pressure; Then by feeding the high-boiling bottoms fraction (topped or atmospheric reduced crude) from the atmospheric still to a second fractionator operated at a high vacuum

LISTEN...LEARN...THINK...GROW21OVERVIEW OF THE TWO DISTILLATION UNITS

LISTEN...LEARN...THINK...GROW22Boiling points & Number of Carbons of Products

STEP IV:Chemical transformation of distillation products Chemical reactions

AFTER DISTILLATION: CHEMICAL PROCESSES

Chemical transformation of crude oil fractions

Distillation in Distillation columns

Cracking reactions in chemical reactors Video: Processes in oil Refinery

CHEMICAL ENGINEERING UNIT OPERATIONS

Unit Operations are the basic physical operations of chemical engineering in a chemical process plant, that is, distillation, fluid transport, heat and mass transfer, evaporation, extraction, drying, crystallization, filtration, mixing, size separation, crushing and grinding, and conveying

What is unit operation?

1.Fluid flow processes, including fluids transportation, filtration, and solids fluidization.2.Heat transfer processes, including evaporation, condensation, and heat exchange.3.Mass transfer processes, including gas absorption, distillation, extraction, adsorption, and drying.4.Thermodynamic processes, including gas liquefaction, and refrigeration.5.Mechanical processes, including solids transportation, crushing and pulverization, and screening and sieving.Chemical engineering unit operations consist of five classes:

1. Fluid Flow Process: Fluid Transportation Pipeline transport is the transportation of goods through a pipe. Liquids and gases are transported in pipelines and any chemically stable substance can be sent through a pipeline

2.Heat transfer processesHeat Exchanger A heat exchanger is a piece of equipment built for efficient heat transfer from one medium to another. The media may be separated by a solid wall to prevent mixing or they may be in direct contact

3.Mass Transfer ProcessesDistillation Distillation is a process of separating the component substances from a liquid mixture by selective vaporization and condensation. Distillation may result in essentially complete separation (nearly pure components), or it may be a partial separation that increases the concentration of selected components of the mixture.

4.Thermodynamic processesGas Liquefaction Liquefaction is used for analyzing the fundamental properties of gas molecules (intermolecular forces), for storage of gases, for example: LPG, LNGAt atmospheric pressure, very low temperatures are required. The natural gas is condensed into a liquid at approximately 162 C (260 F).

5. Mechanical processesCrushing Crushers may be used to reduce the size, or change the form, of waste materials so they can be more easily disposed of or recycled, or to reduce the size of a solid mix of raw materials (as in rock ore), so that pieces of different composition can be differentiated.

FLUID FLOW PROCESSFluids are materials that can flow, and they include both gases and liquids.

What is Mass? Mass is the amount of matter in a given object.Anything made up of matter has mass.

SI Unit of mass is (kg)

Mass(weight)*milligrammg1000 mg=1 ggramgkilogramkg1 kg=1000 gmetric tont1 t=1000 kg

Common Units of mass

Mole & Molecular weight

Periodic Table

Hydrogen (H2) has two hydrogen atoms. The atomic mass or molecular weight of hydrogen is 2. The molecular weight of methane, molecular formula CH4, is calculated as follows.

EXAMPLES atomic masstotal massC1212H14CH416 Molecular weight

1) How many moles of hydrogen (H2) have a mass of 8g

2) What is the molecular weight of water ( H2O) if 2 moles contain 36 grams.

3) What is the total mass of 1 mole of ethane C2H6Class activity

What is Weight ?Weight is a force we get as we press against other objects. You press against a scale to measure your weight. What pulls you against the scale?SI Unit of weight is Newton

Mass and Weight

Weight= Mass x gravity

W= m. g

What is Volume ? Volume is the quantity of three-dimensional space enclosed by some closed boundary.For example, the space that a substance (solid, liquid, gas, or plasma).A measuring cup can be used to measure volumes of liquids.SI unit of volume is m3

Volume milliliter (mL) 1000 mL = 1 L

Cubic centimeter (cm) 1 cm = 1 mL

Liter (L) 1000 L = 1 m

Cubic meter (m)

Common Units of Volume

PrefixSymbolFactorNumericallyNamegigaG1091 000 000 000billionmegaM1061 000 000millionkilok1031 000thousandcentic10-20.01hundredthmillim10-30.001thousandthmicro10-60.000 001millionthnanon10-90.000 000 001billionth

Prefixes for Units

47Mass Density

SI Unit of Mass Density: kg/m3DEFINITION OF MASS DENSITYThe mass density (Rho) is the mass m of a substance divided by its volume V:

48Solidshave highest density

Aluminum2 700

Brass8 470

Concrete2 200

Copper8 890

Diamond3 520

Gold19 300

Ice 917

Iron (steel) 7 860

Lead11300

Quartz 2 660

Silver10 500

Wood (yellow pine) 550

Mass Densities of Common Substances (Unit: kg/m3)

49Liquidshave intermediate densities

Blood (whole, 37C) 1060

Ethyl alcohol 806

Mercury13600

Oil (hydraulic) 800

Water (4 C)1 103

Gases have the smallest densities

Air1.29

Carbon dioxide1.98

Helium0.179

Hydrogen0.0899

Nitrogen1.25

Oxygen1.43

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1) A solid has a density of 917 kg/m3. What will be its mass in a container of 3 m3 ?

2) Water occupies a volume of 5 m3. What is the mass

An unknown gas has a mass of 6.45 kg and occupies a volume of 5 m3. What is the density? What is this gas? Class activity

If we know the total mass of the mixture and the mass of each component, we can calculate the total mass by dividing the mass of each component by the total mass. The total mass composition should be equal to 1

Mass composition ComponentsMass (grams)Mass composition Water15 15/65= 0.23Gasoline40 40/65= 0.61Salt10 10/65= 0.16Total651.00

Find the composition of a mixture containing 1ograms of sugar, 20 grams of water and 5 grams of coffee. Class activity

PIPING SYSTEMS

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Piping SystemsIntroductionBasis for DesignPiping Codes and StandardsDesign of Process Piping SystemsJoints and FittingsValves

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Parts Of Piping SystemsPiping Systems include:

PipeFlangesFittingsBoltingGasketsValvesHangers and supportsInsulations, coverings, coatings

55Everything between equipment and instrumentation is considered piping

Piping systems are like arteries and veins. They carry the lifeblood of modern civilization.

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Piping Systems

56The invention of piping systems is what allowed civilization to develop beyond small villages.Early records show use of hollow log piping and open-channel water distribution systems by the Egyptians, Romans, and Babylonians.

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Piping Systems :Safety FirstPrimary Design Consideration is SafetyEvaluate Process ConditionsTemperaturePressureChemical compatibility/Corrosion allowancesVibration, flexing, bendingExpansion/Contraction due to temperature changeEnvironmental conditionsEvaluate the Effects of a LeakEvaluate Performance in a Fire Situation

57Before starting to design a piping system there are many considerations.Foremost concern in any good design is safety.

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Piping Systems : Special Requirements

Evaluate any Special RequirementsSanitary requirements CleanabilityServiceability ease of maintenance of equipmentPossible contamination of process fluid by piping materials, sealants, or gasketingEarthquake, Hurricane, Lightening, Permafrost

Lowest Cost over the Lifetime

58Does the system have to be disassembled frequently for maintenance or cleaning?Are there trace elements in the piping, sealants, or gasketing that may contaminate the process fluid or utility?What is the total cost of the piping system over the expected life?

59CM4120Unit Operations LabCodes and Standards for Piping SystemsCodes and Standards simplify design, manufacturing, installation process

Standards provide design criteria for componentsstandard sizes for pipedimensions for fittings or valvesCodes specific design/fabrication methodologiesIncorporated into local/regional statute Its the LAW

59Use commonly accepted methods-- reduce design time-- produce safe design-- limit liability.

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Standards for Piping SystemsASME Boiler and Pressure Vessel CodeASME B31: Code for Pressure PipingANSI Standards dimensions for valves, piping, fittings, nuts/washers, etc.ASTM Standards for piping and tubeAPI Specs for pipe and pipelinesAWS, ASHRAE, NFPA, PPI, UL, etc.

60Many professional and standards associations have developed codes and standard practices for the design, assembly, and testing of process piping.

Depending on which industry segment, which part of the plant, the type of service (drinking water vs. oil pipeline) or the type of construction, you would refer to the appropriate code or standard.

ASME boiler and pressure vessel code and B31 are most relevant to ChEANSI American National Standards InstituteASME American Society of Mechanical EngineersASTM American Society for Testing and MaterialsAPI American Petroleum InstitutePPI Plastic Pipe InstituteAWS American Welding SocietyPFI Pipe Fabrication Institute

61ASME B31 is the applicable standard for design of most piping systems in chemical plants

B31.1 Power plant boilersB31.3 Chemical plant and refinery pipingB31.4 Liquid petroleum transportB31.7 Nuclear power plant radioactive fluids

61Within a chemical plant, one section will govern in one part of the plant.In other parts of the plant, a different section may govern the design and installation.

62ASME B31.3 Chemical Plant and Refinery Piping Code Includes:

Process piping in chemical and refinery plantsProcess piping in pharmaceutical and food processingProcess piping in textile and paper plantsBoiler piping

62Most important for chemical engineers

63ASME B31.3 covers:Materials and designFabricationErection and assemblySupportExamination, inspection, and testing

Web reference: www.piping-toolbox.com

63Need to be familiar with B31.3 if you have plant responsibilities.Code is laid out in sections, starting with scope and definitions and progressing thru design, inspection, and testing.

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Piping Systems : Standard Pipe Sizes

Diameters are NominalSizes 12 and less, nominal size < ODSizes 14 and over, nominal size = OD

Wall thickness inferred thru ScheduleSchedule = P/S * 1000Defined Schedules:5, 10, 20, 30, 40, 60, 80, 100, 120, 140, 160

64Specs for piping found in ANSI B36.10 and B36.19

Attempt made to manufacture pipe systems to handle classes of allowable working pressure so that all diameters of pipe of the same pressure rating would be compatible.Schedule

P = maximum allowable working pressure of pipeS = allowable stress in pipe materialHigher the schedule, the thicker the wall, the higher the working pressureThe OD stays the same for all pipe of the same nominal diameterExample: 4 schedule 40 pipeOD = 4.50ID = 4.026

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Piping Systems: Standard Tubing SizesSteel tubing: Diameters are Actual ODWall thickness is specifiedRefrigeration TubingSingle wall thickness available for each sizeActual ODCopper Tubing Nominal sizesType K, L, M

65Pipe is always round, tubing can be round, oval, or rectangular/squareTubing specifications in ANSI B32.5

Example: Steel tubing4 X 4 OD3 ID

Refrigeration tubing: OD w/ 0.035 wall for 0.680 ID

Copper TubingType K is thickest2 type KOD = 2.125Wall = 0.083ID = 1.959

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Piping Systems Materials Metallic piping

Carbon and low alloy steelDuctileInexpensive and availableEasy to machine, weld, cutSome drawbacks

66Can be cut, welded or threaded, and assembled using commonly available skilled labor

Subject to Embrittlement failurescausticshigh pressure steamConversion of carbides to graphiteexposure to high temp over timeSubject to hydrogen stress cracking

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Piping Systems Materials Metallic piping

Alloy Steels including Stainless SteelsGood corrosion resistanceMore difficult to machine, weld, cutSome drawbacks

67Requires special welding techniquesHarder to cut, thread and machineStress corrosion failuresexposure to chloridesEmbrittlement failureAfter exposure to high temp (welding without annealing)

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Piping Systems Materials Metallic piping

Nickel, Titanium, Copper, etc.Copper is used in residential and commercial applications and is widely availableOther materials are expensive and difficult to machine, weld, joinSome incompatibilities with each

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Piping Systems Materials Non-Metallic piping

ThermoplasticsWide range of chemical compatibilityLight weightEasily cut and joinedLow temperature limitsNeed extra supports

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Piping Systems Materials Non-Metallic piping

Fiberglass Reinforced PipeWide range of chemical compatibilityEasily cut and joinedWider temperature limits than thermoplasticsThermal expansion similar to carbon steelSimilar structural performance as carbon steel

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Piping Systems: Materials Others

GlassConcreteLined or coatedGlassRubberCementTeflonZinc (galvanized pipe)

Double Containment piping systems

71Used for low cost, corrosion resistance, long life, ease of cleaningLined pipe is chemical resistant inner layer with structural outer layer

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Piping Systems : Piping Insulation

Prevent heat loss/ gainPrevent condensation below ambientPersonnel protection over 50oCFreeze protection outdoor cold climatesFire protectionNoise control

72Insulating material and covering systemIf the pipe is exposed to washdown or is installed outdoors, need to consider the effects of water on insulating material.Must consider:physical abuse of insulating systemlocation of supportsproximity to adjacent runs of pipeconnections to equipment, valves, and instrumentationMost insulating systems also include a protective covering of cloth, metal, or plastic.

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Piping Systems : Insulation Fiberglass Insulation w/ Asbestos plastered fitting coverings

73Plaster of Asbestos was hand-formed around each fittingOften these systems were cloth covered.

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Piping Systems Insulation Metal Jacketedinsulation covering

74Jacketing can be aluminum, galvanized steel or stainless steel.This is embossed aluminum indoor application.

Also preformed plastic is available.

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Piping Systems : Heat Tracing

Prevents flow problems in cold climatesFreeze protectionLoss of flow due to viscosity increasePrevent condensation in vapor linesMethodsElectricHot Fluids

75Heat tape or pipe runs along side of process pipe.Induction heating of the pipe can also be used.Steam is most common fluid.Glycols in a recirculating system.Insulation covers the pipe and heat tracing.

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Piping Systems : Piping Supports

Prevent strain at connectionsMust allow for expansion/contractionDesign for wind/snow and ice/earthquakeClearance for plant traffic and equipment

76Determining max. space between supports is part of design process.

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Piping Systems : Results of inadequate support

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Results of inadequate support:

May, 1974 Leaking reactor removed from train of reactors and temporarily replaced with a section of pipe

June, 1974 Supports collapse, pipe breaks28 dead, 89 injured, 1800 houses damaged, 160 shops and factories damaged, large crater where plant stood

79CM4120Unit Operations LabPiping Systems

Select in-line components

Determine insulation, coverings, coatings

Design and locate supports and hangers

79Heavy wall pipe may have reduced the ID below the min allowable based on flow velocity criteria.

Using the same temp/press data as for piping design, select the class of fittings and valves.

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Piping Systems : Pipe Joints

ThreadedWeldedSoldered/ BrazedGluedCompressionBell and spigotUpset or expanded

80Most common are threaded and weldedThreaded up to 2Welded butt welded or socket weldedUpset for thin wall pipe and tubing

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Piping Systems : Threaded joints

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Piping Systems : Soldered joints

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Piping Systems : Welded joints

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Piping Systems : Compression joints

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Piping Systems: Mechanical joints

shown on glass drain piping system

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Piping Systems: Pipe Fittings

ForgedCastMalleable Iron

Pressure/Temperature Rated by Class125, 250, or 2000, 3000, etc.Need a look-up table to determine max. allowable P for the design temperature

86Used to connect or adapt pipe to other pipe or equipment.Used to change directions.Used to change pipe diameter or terminate a pipe run.Forged Steel in threaded or socket weldCast Iron, bronze, brass Malleable Iron generally in threaded

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Fittings for joining 2 sections of pipe:

Coupling

Reducing Coupling

Union

Flange

87Couplings join two lengths of pipe

Reducing couplings used for joining two lengths of pipe of different diameters. Can be concentric or eccentric.

Unions and flanges are used when piping must be dis-assembled

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Piping SystemsFittings for changing directions in pipe:

45o Ell

90o Ell

Street Ell

88Both short and long-radius fittings available

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Piping SystemsFittings for adding a branch in a run of piping:

Tee

Cross

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Piping SystemsFittings for blocking the end of a run of piping:

Pipe plug

Pipe cap

Blind Flange

90Caps, plugs, and blind flanges are used to block off the end of a pipe

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Piping SystemsMisc. pipe fittings:

Nipple

Reducing bushing

91Nipples lengths up to 12 inch standard, other lengths available

Reducing bushings are typically used to reduce the size of a tank or vessel fitting to the size of the pipe run.Not normally used as in-line fittings.

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Piping Systems: Valves Gate Valve:Used to block flow (on/off service)

Sliding gateon knife-gatevalve

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Piping Systems : Globe ValveGlobe Valve:Used to regulate flow

Cut-away showsstem seal plug and seat

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Piping Systems : Ball Valve Ball Valve:Typically used as block valve

Quarter-turn valve

Cut-away shows ball and seat

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Piping Systems: Butterfly valve Butterfly Valve:Can be used for flow control or on/off

Valve actuator/ positioner for accurate flow control

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Piping Systems: Check ValveCheck Valves:Used to prevent backflow

Piston check

Swing check

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Flow of fluids

Fluid Flow Mass flow rate: Av (kg/s)Continuity: 1A1 v1 = 2A2 v2 i.e., mass flow rate the same everywhere e.g., flow of river

A1 r1A2 r2

v1v2

Paul E. TippensFluid Motion

The lower falls at Yellowstone National Park: the water at the top of the falls passes through a narrow slot, causing the velocity to increase at that point.

Fluids in Motion

All fluids are assumed in this treatment to exhibit streamline flow.Streamline flow is the motion of a fluid in which every particle in the fluid follows the same path past a particular point as that followed by previous particles.

Since 1989 there were at least 23 distinct type of technologies available for the measurement of flow in closed conduit. The performance of flowmeters is also influenced by a dimensionless unit called the Reynolds Number. The Reynolds number is used for determined whether a flow is laminar or turbulent. Laminar flow within pipes will occur when the Reynolds number is below the critical Reynolds number of 2300 and turbulent flow when it is above 4000. TYPES OF FLOW

Types of Flow

1) The velocity of water in a pipe is 1.5 m/s. Calculate the Reynolds number if the diameter is 0.1 m and the density and viscosity are respectively 1000 kg/m3 and 0.001 Pa.s

2) What will be the velocity for a Reynolds number of 2000. Class activity

Quantity of a gas or liquid moving through a pipe or channel within a given or standard period (usually a minute or hour)

What is a Flow Rate ?

What is mass flow rateMass flow rate is the mass of a substance which passes per unit of time. Its unit is kg/s (kilogram per second) in SI units,

1) What is the mass flow rate of 5 kg of water passing through a tube during 1 min ?

2) In 20 seconds, water passes a tube with a mass flow rate of 2kg/s. What is the mass of water?

Class work

Volume flow rate Volume flow rate, rate of fluid flow or volume velocity) is the volume of fluid which passes per unit time. The SI unit is m3/s (cubic meters per second.

Volume flow rate and velocity

Volume flow rate = Area x velocity Q= A.v

A = Cross-sectional Area of Pipe (SI: m2) v = Velocity of the fluid in the pipe (SI: m/s)

1) In how many seconds, 3 m3 of water having flows with a rate of 10 m3/s

2) Water flowing in a tube having a area of 10 cm2. If the flow rate is 1 m3/s, what will be the velocity in m/s?Class work

Volume and mass flow rates Mass flow rate is equal to the volumetric flow rate times the density.

= .QSince Q = A. v

=.A . v

A liquid having a density of 800 kg/m3 has a volumetric flow rate of 50 m3/s. What is its mass flow rate is kg/s?

A fluid has a density of 1000 kg/m3 flows in a pipe of surface are equals to 10 cm2. If the velocity is 1 m/s, what are the volumetric and mass flow rates

Class activity

Molecular flow rate

1) What is the molecular flow rate of water if the mass flow rate is 100 kg/s and the molecular weight is 18

2) What is the mass flow rate of gasoline if the molecular flow rate is 50 moles/s and the molecular weight is 80.

Class activity

HOW IS FLOW MEASURED

September 23, 2004115Basic Flow Measurement

September 23, 2004116

Type of FlowmetersIndustrial Flowmeter Usage

Orifice plate

An orifice plate is a thin plate with a hole in it, which is usually placed in a pipe. When a fluid passes through the orifice, it is forced to converge to pass through the hole, the velocity increases and the fluid pressure decreases

Positive displacement A positive displacement meter is a type of flow meter that requires fluid to mechanically displace components in the meter in order for flow measurementThese devices consist of a chamber(s) that obstructs the media flow and a rotating or reciprocating mechanism that allows the passage of fixed-volume amounts.

Selection of Flow meters

Transport of liquids Pumps

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INTRODUCTIONThe pump is mechanical device which conveys liquid from one place to another place.It can be defined as a hydraulic machines which converts the mechanical energy into hydraulic energy ( Pressure) .The pump is power absorbing machine. The power can be supplied to the pump by a prime mover like an electric motor, an internal combustion engine or turbine..

Pressure definitionPressure is the action of one force against another over, a surface. The pressure P of a force F distributed over an area A is defined as: P = F/A

Pressure References Absolute pressureThe pressure is referenced to zero absolute. Absolute pressure can only have a positive value.

Gauge pressureThe pressure is referenced to atmospheric pressure:

P ( gauge ) = P ( absolute) Atmospheric pressure

Vacuum pressureAny pressure lower than atmospheric pressure is called vacuum pressure.

UNITS OF PRESSURESI UNITS: 1Pa = 1N/M2=1KG/S2.M 1ATM (ATMOSPHERIC PRESSURE)= 100 kPa 1 ATM= 101 kN/M2 1ATM= 760 MM. HG US UNITS: 1PSIA = 1LBF/IN2 1PSIA = 6894.7 Pa 1ATM= 14.696 PSIA

LISTEN..LEARN..THINK..ENJOY YOURSELF124

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1) A liquid in a pipe has an absolute pressure of 50 kPa. What is the reading in the gauge if the atmospheric pressure is 101 kPa?

2) You read in a manometer a pressure of -10 kPa. What is the absolute pressure ? Convert 50 kPa into atm. Convert 2 atm into Psi. Class activity

Head Connect a tube to the discharge of a pump and measure the water height, that the head of the pump.

Head is the height at which a pump can raise water up.

More pressure the pump delivers, the higher the head will be in the figure.

Pressure and Head

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1) What is the head in m when the pressure is 98100 Pa and the density of the liquid is 1000 kg/m3.g = 9.81 m/s and gc= 1kg.m/s2

h = (98100 x 1)/ ( 1000x 9.81)= 10 m

2) what is now the pressure if the head is 5 m?Example + activity

Pump Performance CurveA mapping or graphing of the pump's ability to produce head and flow

Pump Performance CurveStep #1, Horizontal Axis

The pump's flow rate is plotted on the horizontal axis ( X axis)Usually expressed in Gallons per Minute

Pump Flow Rate

Pump Performance CurveStep #2, Vertical Axis

Pump Flow RateThe head the pump produces is plotted on the vertical axis (Y axis)Usually express in Feet of WaterHead

Mapping the Flow and the Head

Pump Flow RateMost pump performance curves slope from left to right

Performance Curve

Head

Pump Performance CurveImportant Points

Shut-off Head is the maximum pressure or head the pump can produceNo flow is produced

Pump Flow Rate

Head

Shut-off Head

Pump Performance CurveImportant Points

Pump Flow Rate

Head

Maximum Flow

Maximum Flow is the largest flow the pump can produceNo Head is produced

System Performance CurvesSystem Performance Curve is a mapping of the head required to produce flow in a given system

A system includes all the pipe, fittings and devices the fluid must flow through, and represents the friction loss the fluid experiences

System Performance CurveStep #1, Horizontal Axis

System Flow RateThe System's flow rate in plotted on the horizontal axis ( X axis)Usually expressed in Gallons per Minute

System Performance CurveStep #2, Vertical Axis

Pump Flow RateThe head the system requires is plotted on the vertical axis (Y axis)Usually express in Feet of WaterHead

System Performance CurveStep #3, Curve MappingThe friction loss is mapped onto the graphThe amount of friction loss varies with flow through the system

Head

Pump Flow RateFriction Loss

Head

Pump Flow Rate

The point on the system curve that intersects the pump curve is known as the operating point.

CLASSIFICATION OF PUMPS Positive displacement pumpsReciprocating pumps Rotary pumps

Roto -dynamic pumpCentrifugal pump Propeller pumpMixed flow pump

POSITIVE DISPLACEMENT PUMPS: RECIPROCATING PUMPSReciprocating pump classification Reciprocating pumps can be classified based on1. Sides in contact with water a) Single acting Reciprocating pump b) Double acting reciprocating pump 2. Numbers of cylinder used a) Single cylinder pump b) Two cylinder pumps c) Multi-cylinder pumps)

This machine consists of an IMPELLER rotating within a case (diffuser)

Liquid directed into the center of the rotating impeller is picked up by the impellers vanes and accelerated to a higher velocity by the rotation of the impeller and discharged by centrifugal force into the case (diffuser).Centrifugal Pumps

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Pump Terminology

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Diameter of the Impeller

Thickness of the impeller

Centrifugal ImpellersThicker the Impeller- More WaterLarger the DIAMETER - More PressureIncrease the Speed - More Water and Pressure

Impeller Vanes

Eye of the ImpellerWater Entrance

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Two Impellers in Series

Direction of FlowTwice the pressureSame amount of water

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Multiple Impellers in SeriesPlacing impellers in series increases the amount of head producedThe head produced = # of impellers x head of one impeller

Direction of Flow

Direction of Flow

Head

Pump Flow Rate

Circulator 1Circulator 2Circulator 3PUMP SELECTION:3 pumps

Controlling Pump PerformanceChanging the amount for friction loss or "Throttling the Pump" will change the pump's performance

Head

Pump Flow Rate

PUMP SELECTION

Valve OpenValve Partially OpenValve Barely Open

Compressors

What is a Compressor?A mechanical device that increases the pressure of a gas by reducing its volume.Similar to a pump Increases the pressure on a fluid and transport it through a pipe.What is key difference between a Fluid and a Gas?Compressibility a gas is compressibleWhat happens to gas volume as it is compressed?DecreasesWhat happens to the Temperature of the Gas as it is compressed?Increases

Compressors

Compressors are classified by how they workTwo Categories of CompressorsPositive DisplacementDynamicWhat is a Positive Displacement Compressor?A compressor that confines successive volumes of gas within a closed space in which the pressure of the gas is increased as the volume of the closed space is decreased. Intermittent FlowWhat is a Dynamic Compressor?A compressor using a rotating mechanism to add velocity and pressure to gas.Continuous Flow

Compressors

Two types of Positive Displacement Compressors:Reciprocating RotaryTwo Types of Dynamic CompressorsCentrifugalAxial

Compressors

Reciprocating CompressorsHow does it work?Piston movement in a cylinder connected to a rod and crankshaftDownward piston motion, low pressure gas enters the chamberUpward piston motion, gas is compressed and exits the chamberVideo

Reciprocating Compressors

Reciprocating CompressorsHigh Horsepower Applications Common in natural gas transmission lines.Processes for high pressure delivery of gasses

Air Conditioning CompressorsSome manufactures (Frigidaire) use rotary compressorsAC Compressors (and other small appliance applications) are Hermetic or Semi-Hermetic

Compressors

Rotary CompressorsHow do they it work?When a rotating mechanism spins past the inlet valve, it creates a vacuum. The fluid flows out of the valve behind it, filling the vacuum. As it approaches the outlet valve, the chamber shrinks, creating more pressure on the fluid. The fluid has nowhere to go but out of the outlet valve, so it shoots out of it. Then the rotating mechanism continues on to draw more fluid at the inlet valve.How it works Video

Rotary Compressors

Common Types of Rotary CompressorsScrewVaneScrollScrewTwo meshing helix screws RotorsCompact and smooth running2 types - Oil Free and Oil FloodedOil Free No assistance from oil to cool and assist in sealing .Oil Flooded Oil injected to aid in sealing and provide cooling. Separator downstream to capture the oil

Rotary Compressors

Vane CompressorsVane housing on a off centered shaft Vanes slide in an out always making contact with the compressor wallsGas enters in the largest openingExits the smallestGood for low pressure applications EfficientHeat controlled by oil injectionVane Compressors

Scroll CompressorHow it works2 Spirals1 stationary, 1 orbits without rotating1st orbit entraps inlet gasSubsequent orbits compresses gas and exited out the centerGenerally 2-3 orbits for a full cycleVideoAdvantagesCompactSteady flowLow energy useQuietSmooth operation

Scroll Compressors

What is a Dynamic Compressor?A compressor using a rotating mechanism to add velocity and pressure to gas.Continuous FlowWhat are the Two Types of Dynamic Compressors?CentrifugalAxial

Dynamic Compressors

Centrifugal CompressorsRotating disk (impeller) forces gas to the rim of the impeller, increasing velocityThe diffuser converts the velocity energy to pressure energy. Primarily used for continuous, stationary service in industries such as refineries, chemical plants and snow making operationsSingle Stage and Multi-Stage CompressorsHow a Centrifugal Compressor WorksCentrifugal Compressors

Impeller Most critical part of a centrifugal compressorCompressor performance determined by impeller:SizeShapeSpeed3 types of ImpellersClosedMost commonShroud covering both sides of the bladeCenter eye hole for gas to enterUsed in Multi-stage compressorsSemi openOpenCompressors

Multi-Stage CompressorsDiaphragmSpecially designed casing wall separating the stagesGas passes through the difuserPasses through the return channel in the diaphragmControlling Axial Load on the ShaftBearing ReviewThrust BearingMulti Stage Compressors

Axial CompressorsGas flows parallel to the axis of rotationUnlike centrifugal that has radial componentsHas rotating and stationary componentsRotating airfoil rotorStationary airfoil statorSimilar number of these on a shaftVideoAxial Compressors

Axial CompressorsHigh VolumeHigh EfficiencyHigh CostCommon UsesGas TurbinesJet enginesPower stationsNickname Superchargers

Axial Compressors

Class Activity SUBMIT YOUR WORK

1) How many moles of carbon have a mass of 36g

2) What is the molecular weight of methane ( CH4) if 2 moles contain 32 grams.

3) What is the total mass of 1 mole of propane C3 H8Class activity

1) A solid has a density of 1600 kg/m3. What will be its mass in a container of 5.5 m3 ?

2) Water occupies a volume of 15 m3. What is the mass

An unknown gas has a mass of 3.45 kg and occupies a volume of 3 m3. What is the density? Class activity

Find the mass composition of a mixture containing 20 grams of water , 35 grams of juice and 5 grams of sugar. Class activity

1) The velocity of water in a pipe is 2 m/s. Calculate the Reynolds number if the diameter is 0.15 m and the density and viscosity are respectively 800 kg/m3 and 0.003 Pa.s

2) What will be the velocity for a Reynolds number of 4000. Class activity

1) What is the mass flow rate of 6 kg of water passing through a tube during 45 seconds ?

2) In 10 seconds, water ( density = 1000 kg/m3) passes a tube with a mass flow rate of 2m3 /s. What is the mass of water?

Class work

1) In how many seconds, 5 m3 of water having flows with a rate of 8 m3/s

2) Water flowing in a tube having a area of 7 cm2. If the flow rate is 1.5 m3/s, what will be the velocity in m/s?Class work

A liquid having a density of 1000 kg/m3 has a volumetric flow rate of 60 m3/s. What is its mass flow rate is kg/s?

A fluid has a density of 1000 kg/m3 flows in a pipe of surface are equals to 2 m2. If the velocity is 1.5 m/s, what are the volumetric and mass flow rates

Class activity

1) What is the molecular flow rate of a liquid if the mass flow rate is 70 kg/s and the molecular weight is 38

2) What is the mass flow rate of gasoline if the molecular flow rate is 50 moles/s and the molecular weight is 80.

Class activity

1) A liquid in a pipe has an absolute pressure of 150 kPa. What is the reading in the gauge if the atmospheric pressure is 101 kPa?

2) You read in a manometer a pressure of 40 kPa. What is the absolute pressure ? Convert 0.5 atm into Pa. Convert 50 kPa into Psi. Class activity

1) What is the head in m when the pressure is 100100 Pa and the density of the liquid is 800 kg/m3.g = 9.81 m/s and gc= 1kg.m/s2

Example + activity