Chemical Engineering Design Princi-ples, Practice, and Economics ofPlant and Process Design

By G. Towler and R. Sinnott, Butterworth-Heinemann, Boston, MA, 2007, 1245 pp. $89.95.

Overall this chemical process design text-book is well conceived in terms of content. Italso contains several unique features such as alist of key learning objectives at the beginningof each chapter, significant references through-out, nomenclature at the end of each chapter,and supplementary materials available on adop-tion (power point lecture slides and a solutionmanual), all of which I find useful for teacherand student.

The first three chapters of the book, theintroduction, fundamentals to material balan-ces, and fundamentals of energy balances andutilization, provide perspective and fundamen-tal introductory material for the student. Thesechapters easily form the basis for an introduc-tory design class for freshman or sophomorestudents who have not yet taken or are con-currently taking the traditional first course inchemical engineering in mass and energy bal-ancing. Chapter 1 presents the notion thatdesign is usually very vaguely defined exer-cise, but then takes the student through thebasic principles of design from the generationof conceptual designs to computations, equip-ment design, financial considerations anddealing with trade-offs using optimization.The introduction also contains more detailedmaterial on optimization than most designtexts, covers single and multivariable optimi-zation, constraints in design, linear and non-linear programming, mixed integer nonlinearprogramming and superstructure considera-tions, and ends the chapter with an exampleillustrating the optimization of total annual-ized costs for a distillation involving fivecomponents.

The subject of chapter 2 is mass balancesand is well conceived. While the inclusion ofthe equivalence of mass and energy and theEinstein relationship E ¼ mc2 seems a bit outof place, the authors do an excellent job of pre-senting standard topics such as defining systemboundaries, the importance of units, the role ofa basis in mass balance calculations, and theneed to solve simultaneous algebraic equations.I particularly like the parts of the chapter thatcover bypass and purge streams, because theyoften go unmentioned in many texts. Unfortu-nately, there is very little space devoted tounsteady-state mass balance calculations, andthis is something I see as a general weakness ofmost texts, not just this one. Understandingunsteady-state mass balancing is important tounderstanding process dynamics and control,and with the recent emphasis on synergisticdesign and control, I would have expected moreon this and related subjects. Process control, inthis text, is embedded in Chapter 5: Piping andInstrumentation.

Chapter 3 on energy balances draws a valua-ble connection between fundamental concepts

like internal energy, heat, work, enthalpy andheat capacities covered in traditional classicalthermodynamics courses and energy balancingin the design process. However, the first 25pages of this chapter are essentially a review ofcertain aspects of sophomore thermodynamicsand, as in the chapter on material balances,there is very little material on unsteady-stateenergy balances. The remainder of chapter 3 isdevoted to energy recovery and heat exchangernetwork design using pinch technology. Consid-erable space is given to heat exchanger networksynthesis and design for networks involvingmultiple hot and cold streams. I find the subjectmaterial in this part of chapter 3, which is oftenabsent in most design texts, informative anduseful for beginning and senior students. Fartoo often students in design are not introducedto synthesis concepts, but rather their design ex-perience is relegated to the use of steady-statesimulators with fixed configurations to perform‘‘design’’. It is nice to see an approach to teach-ing design that includes synthesis as an integralpart of the total design effort.

Chapter 4 is concerned with process flowsheeting. Various types of process representa-tions and key information included in a typicalflow diagram are described. Commonly usedprocess simulation programs available to aca-demic and industrial practitioners and theirmain attributes are also listed. The authors thendescribe the basic steps commonly employed inconstructing a flow sheet, including:

1. Specification of components and choice ofappropriate physical properties models.

2. Specification of typical process units.

3. The use of spreadsheets.

4. User-specified units.

Many aspects of building a flow sheet arenicely illustrated with UniSim Design processsimulator. The sequential modular and equa-tion-oriented approaches to flow sheet computa-tion are well described, as are the advantagesand disadvantages of each with regard to proc-esses with recycle. The concept of ‘‘tearing’’recycle streams in the sequential modularapproach is nicely presented with the help of asimple reaction-separation-recycle process andseveral traditional methods of converging tearstreams are presented. While material on flow-sheet optimization, dynamic simulation andconcepts like real-time optimization are onlymentioned in passing, on the whole, this chapteris a good introduction to steady-state processflow sheeting.

Chapter 5 is entitled piping and instrumenta-tion, and introduces the student to pumps andcompressors, net positive suction head, and me-chanical aspects of pumps and pump seals —something often lacking in other textbooks. Asimilar approach is presented for piping withregard to ASME standards for piping, pipingselection, materials of construction, and so on. Ifind the placement of control in this chapter abit unusual, but not detrimental to the flow ofthe book. Typical control schemes for level,flow, temperature, and pressure control areillustrated for single input-single output, and

multiple input-multiple output processes. How-ever, the material on process control is notconnected to dynamical simulation (perhapsbecause there is little in the textbook ondynamic simulation) so the student is left a bitin the dark.

The subject of chapter 6 is project cost esti-mation and, together with chapters 1, 2 and 3,is intended to provide a good introduction tochemical process design for beginning students(freshman or sophomore level) who have nottaken or are currently taking the traditional in-troductory chemical engineering mass andenergy balance course. Personally I believe thatunless students receive some hands on experi-ence using a process simulator, much of theauthors’ intent with regard to chapters 1, 2, 3,and 6 as an introduction to design will be lost.Students learn by doing and, in design, thisinvariably means performing numerical simula-tions so I would have included chapter 5 in thisshort list of chapters that form a good introduc-tion. Nevertheless, I feel chapter 6 is an impor-tant chapter because it gives the student basicprocess economics early on in their designtraining, because economics is what drives theindustry, and because students need to knowthis upfront. This chapter treats many of thestandard aspects of economics, including capitalinvestment costs, operating costs, purchasedequipment costs, and so on, with many exam-ples given in isolation. What might haveworked better would have been a process rede-sign exercise with a timely focus on reducingenergy consumption. That is, given an existingprocess with significant energy consumption,consider the redesign of that process to improveoverall energy efficiency, and then pose for thestudent the many related questions that havebearing on overall process economics.

Chapter 7 is concerned with materials of con-struction and provides a basic overview of theimportance of and commonly encountered issuesin selecting materials for various services.

Chapter 8 deals with design data and designinformation, and shows the student how to findphysic-chemical data, how it can be predictedwhen no data is available, and how to choosean appropriate phase equilibrium model. Whilethe authors do describe the use of handbooksand other reference books, correlations, tables,charts, and some group contribution approachesfor obtaining basic physical properties data(density, thermal conductivity, heat capacity,etc.), in my opinion their approach does notteach the student to be resourceful. While wellintended, pointing the way for students is notalways the best approach to learning. In manyof my courses, I often deliberately leave infor-mation out, tell students what I have done, andwhy I have left information out, and thenstrongly encourage them to become resourceful.

Process safety and loss prevention is the sub-ject of chapter 9. This is a very useful chapterthat clearly reflects the industrial background ofthe authors. In my opinion, industry takes safetyfar more seriously than academia does. Thischapter gives the student a solid appreciationfor the seriousness with which safety should be

AiChE Journal, Vol. 54, 3034–3035 (2008)� 2008 American Institute of Chemical EngineersDOI 10.1002/aic.11633Published online October 6, 2008 in Wiley InterScience (www.interscience.wiley.com).

AIChE Journal3034 DOI 10.1002/aic Published on behalf of the AIChE November 2008 Vol. 54, No. 11 AIChE Journal

viewed and discusses in some depth topics thatare always intended to be part of material safetydata sheets (MSDS), but are often not such astoxicity and other exposure limits, flammability,flash points, etc. Other processing issues suchas excessive pressures and temperatures, identi-fication of electrical sources of ignition, andexplosion are also discussed. The safety check-list provided at the end of this chapter is invalu-able in my opinion. A good addition to thischapter might have been an in-depth study of arecent industrial accident (e.g., the explosion inthe Texas City, TX plant in which there wasloss of life). Case studies are often helpfulbecause they are real and leave a meaningfulimpression, and could have been presented in afactual manner as learning experience.

As noted by the authors in the preface, chap-ters 10 through 13 are concerned with equip-ment selection, which is often overlooked inmany design textbooks. While some of the ma-terial in these chapters can be found in othertexts, like the topics on distillation design inchapter 11, it is unfortunate that the authors do

not consider this material part of the core mate-rial in design courses in terms of subject matter.Students often learn very little if anything, forexample, about tray hydraulics and entrainmentin mass transfer and stage-wise operationscourses. I feel some of the material in chapters10 through 13 should be selectively included insenior design courses (not just in a seconddesign course as the authors suggest), perhapson the basis of relevance to a particular designproject. Many chemical engineering curriculastill require two design courses, and, therefore,this often overlooked material could easily beincluded.

The final chapter of the book deals with plantlayout. Many of the aspects of site selection, plantlayout, and utilities are not necessarily somethinga design engineer is directly concerned with.These decisions are often made at a much highermanagerial level. Nonetheless, some familiaritywith basic considerations associated with build-ing plants is useful. Perhaps the most useful partof chapter 14 for the design engineer is the mate-rial on environmental impact.

Overall, the book is well conceived and wellwritten. The 14 main chapters interweave sub-ject material rather well. There are also nineappendices that range in content from MSDS,to conversion factors to sample design projects.Not all of these appendices are strictly neces-sary and some omissions might have actuallyfostered more student resourcefulness. Problemsat the end of each chapter in a design text areunnecessary. In my opinion, design shouldalways be taught in the context of a course-long project, not as a series of problems at theend of each chapter. Finally, do I recommendthis textbook for design? Yes! I think it makesa good teaching text, as well as a valuable ref-erence book for students within the context of ateam-based design project in capstone designcourses.

Angelo LuciaUniversity of Rhode Island

Crawford Hall, 16 Greenhouse RoadKingston, RI 92881

Microbial Fuel Cells

By Bruce E. Logan, Wiley InterScience, Hobo-ken, NJ, 2008, 216 pp. $90.50.

The book reviews the current status of Micro-bial Fuel Cells covering mainly the research andexperience gained by the author and is introduc-tory in nature. The book covers broad themesrelevant to the area, however not detailing manyaspects to a depth. The book discusses currentand future energy demands and the resultinggreenhouse emissions, and the need for MFCs.

The book starts with describing microbiologyof exoelectrogens, that is microorganisms capa-ble of directly transferring electrons to a chemi-cal or a material that is not an immediate elec-tron acceptor. The chapter reviews recent workin the area of nanowire generation by such amicroorganism and various methods that can beused to formulate MFCs using different mecha-nisms used by different types of microorgan-isms. The next chapter describes basics of volt-age generation in a fuel cell. Simple thermody-namic calculations to demonstrate the capabilityof MFC to generate electricity and hydrogenare covered. Voltage generation by fermentative

systems, the enzymatic and anodic capacitiesare elegantly described. The book also introdu-ces to power generation, energy efficiency cal-culations and its applications to MFCs.

A chapter is dedicated in the book thatdescribes the challenges in the choice of mate-rial for the anode and cathode to be used in aMFC. The main objective is in the choice ofmaterial that maximizes power generation andcolumbic efficiency. A good comparative analy-sis of various materials used as anode and cath-ode are described. The book also introducesmembrane based hydrogen fuel cells. Thebasics are covered including definitions ofchemical flux and calculations of mass-transfercoefficients in such reactors. The chapter is ex-haustive in detailing all the aspects in choosingmaterials in MFCs.

After covering microbiology, basics of volt-age and power generation, materials, the bookdescribes the reactor architecture of MFCs. Theequipment description of various reactor typessuch as continuous flow tubular reactor,packed-bed reactors, flat-plate reactors, fed-batch reactors are described. This leads to thenext chapter on basics of kinetics and masstransfer. The book makes an attempt to describe

Monod’s model of growth kinetics and relate

that to the mass-transfer limitations in biofilm.

There is a specific chapter detailing MFCs for

hydrogen production detailing the definitions

necessary to evaluate efficiency and perform-

ance. The last three chapters cover recent de-

velopment of use of MFCs for wastewater

treatment, other MFC technologies and future

directions.The book gives an overview of the current

status in MFC technology. The book is self-suf-ficient and provides relevant introductory mate-rial for a general reader not familiar with areassuch as microbiology, materials, kinetics, masstransfer, etc. This makes the book readable fora broad set of researchers with varied back-grounds interested in microbial fuel cells.Another useful aspect of the book is that eachchapter contains simple quantitative illustrationof a concept which helps in easy comprehen-sion of the broad topics covered in the book.However, the overview of various topics makesthe reading simple, but the book cannot offer indepth knowledge in any specific area. The bookcan be useful as an easy reference material inthe important area of MFCs.

K. V. VenkateshDept of Chemical Engineering

Indian Institute of Technology BombayPowai, Mumbai 400 076, India

E-mail: venks@iitb.ac.in

AiChE Journal, Vol. 54, 3035 (2008)� 2008 American Institute of Chemical EngineersDOI 10.1002/aic.11634Published online October 9, 2008 in Wiley InterScience (www.interscience.wiley.com).

AIChE Journal November 2008 Vol. 54, No. 11 Published on behalf of the AIChE DOI 10.1002/aic 3035