Excerpts

Preface This book represents the culmination of many years of teaching experience in the senior design course at West Virginia University (WVU) and University of Nevada, Reno. Although the program at WVU has evolved over the last thirty years and is still evolving, it is fair to say that the current program has gelled over the last fifteen years as a concerted effort by the authors to integrate "design" throughout the undergraduate curriculum in chemical engineering. We view design as the focal point of chemical engineering practice. Far more than the development of a set of specifications for a new chemical plant, design is the creative activity through which engineers continuously improve the operations of facilities to create products that enhance the quality of life. Whether developing the grass-roots plant, proposing and guiding process modifications, or troubleshooting and implementing operational strategies for existing equipment, engineering design requires a broad spectrum of knowledge and intellectual skills to be able to analyze the big picture and the minute details and, most important, to know when to concentrate on each. Our vehicle for helping students develop and hone their design skills is process design rather than plant design, covering synthesis of the entire chemical process through topics relating to the preliminary sizing of equipment, flowsheet optimization, economic evaluation of projects, and the operation of chemical processes. The purpose of this text is to assist chemical engineering students in making the transition from solving well-posed problems in a specific subject to integrating all the knowledge that they have gained in their undergraduate education and applying this information to solving open-ended process problems. Many of the "nuts and bolts" issues regarding plant design (for example, what schedule pipe to use for a given stream or what corrosion allowance to use for a vessel in a certain service) are not covered. Although such issues are clearly important to the practicing engineer, several excellent handbooks and textbooks are available to address such problems, and these are cited in the text where they apply. In the second edition, we have rearranged material from the first edition and have added several new chapters. The new material includes the following: Chapter 0, titled Outcomes assessment, addresses the subject from both student and faculty perspectives, including the relationship to the ABET EC 2000 criteria for accreditation of engineering programs in the United States. The material in Chapter 1 on process diagrams has been expanded to include some preliminary plant layout information. The topology of the chemical plant is introduced with the help of three-dimensional graphics tools. A digital "movie" is included on the CD accompanying the book, which gives a "virtual plant tour" of a simple chemical process. Material on the structure, synthesis, and conceptual design of chemical processes is added to the new Chapter 2. The hierarchical approach to conceptual design is presented with several examples. The chapter on capital cost estimation (new Chapter 5) has been revised, and new capital cost estimates for process equipment are presented (in Appendix A) which are based on an extensive survey of equipment manufacturers carried out during 2001. The CAPCOST program for estimating the fixed capital cost of building a new chemical plant has been revised extensively. The program is now written in the form of a Microsoft¨ Excelª template. The new capital costs from Chapter 5 and Appendix A are included. In addition, a full financial analysis, including operating costs, raw material costs, cash flow diagrams, and a Monte Carlo simulation feature, is included. Detailed calculations on how to estimate utility costs are included in the new Chapter 6 (old Chapter 3). Raw material costs and fuel costs have also been updated. The latest tax code information and details of the Modified Accelerated Cost Recovery System (MACRS) method of depreciation are included in Chapter 7 (old Chapter 4). A new section has been added to Chapter 8 (old Chapter 5) on how to quantify risk and the application of probabilistic (Monte Carlo) techniques to the evaluation of project profitability. The chapter detailing the synthesis of a process, Chapter 10 (old Chapter 17), has been expanded. Specifically, the section on separation sequencing has been greatly enhanced. Examples of alternative distillation sequences for both nonazeotropic and azeotropic systems are discussed. A qualitative description of the use of residual curve analysis and its application to azeotropic systems has been included. The section detailing the choice of which thermodynamic package to use in a simulation has been expanded, and several examples of how and when to use different thermodynamic options are covered in chapter 11 (old Chapter 18). The old Chapter 18 on optimization has been split into two chapters (12 and 13). Chapter 12 covers the overall process optimization. Chapter 13 covers the area of pinch technology. The heat exchanger networks (HENs) section has been expanded to cover issues relating to the estimation of heat exchanger surface area for the network and the effect of materials of construction on the cost of the network. The design of mass exchanger networks that parallels the design of HENs has been added to this chapter. New software HENSAD (Heat Exchanger Network Synthesis Analysis and Design) is provided on the CD accompanying the textbook. This software allows the user to construct temperature interval, cascade, temperature- enthalpy diagrams, estimate the optimal approach temperature, and design HENs. The chapters on ethics (21) and safety (22) have been updated to include current web sites, and additional examples have been added. The new Chapter 23 gives a brief introduction to green engineering design methods. The pollution prevention hierarchy is introduced. Green chemistry principles are presented, and flowsheet analysis for pollution prevention is discussed. Examples of the economics of pollution prevention activities and the life cycle analysis module, previously in old Chapter 21 (new Chapter 22), are presented. Chapter 24 introduces the topic of chemical product design. This subject is defined to include application of chemical engineering principles to the development of new devices, new chemicals, new processes to produce these new chemicals, and marketable technology. Examples from our experience with class assignments involving chemical product design are included. Chapter 25 covers the essential elements of team building and teamwork. The reader is guided though the essential stages of teamwork in the context of a design assignment. Choice of group members, initial organization determination, roles within and outside the group, group management, team building, team member roles and responsibilities, and team self-evaluation are described. References to the most accessible team-building literature are given. Examples of problems typically encountered by poorly functioning teams are included. As a result of our integrated approach to design, and in response to feedback on the first edition, we have rearranged and modularized this book into six sections: Section 1--Conceptualization and Analysis of Chemical Processes Section 2--Engineering Economic Analysis of Chemical Processes Section 3--Synthesis and Optimization of Chemical Processes Section 4--Analysis of Process Performance Section 5--The Impact of Chemical Engineering Design on Society Section 6-- Interpersonal and Communication Skills This reorganization of material provides a more logical ordering of topics. In Section 1, the student is introduced first to the principal diagrams that are used to describe a chemical process. Next, the evolution and generation of different process configurations are covered. Finally, the analysis of existing processes is covered. In Section 2, the information needed to assess the economic feasibility of a process is covered. This includes the estimation of fixed capital investment and manufacturing costs, the concepts of the time value of money and financial calculations, and finally the combination of these costs into profitability measures for the process. Section 3 covers the synthesis of a chemical process. The minimum information required to simulate a process is given, as are the basics of using a process simulator. The choice of the appropriate thermodynamic model to use in a simulation is covered and the choice of separation operations is covered. In addition, process optimization and heat integration techniques are covered in this section. In Section 4, the analysis of the performance of existing processes and equipment is covered. The material in Section 4 is substantially different from that found in most textbooks. We consider equipment that is already built and operating and analyze how the operation can be changed, how an operating problem may be solved, and how to analyze what has occurred in the process to cause an observed change. In Section 5, the impact of chemical engineering design on society is covered. The role of the professional engineer in society is addressed. Separate chapters addressing ethics and professionalism, health, safety, and the environment, green engineering, and chemical product design are included. Finally, in Section 6, the interpersonal skills required by the engineer to function as part of a team and to communicate both orally and written are covered. An entire chapter is devoted to addressing some of the common mistakes that students make in written reports. Finally, two appendices are included. Appendix A gives a series of cost charts for equipment. This information is embedded in the CAPCOST program for evaluating fixed capital investments and process economics. Appendix B gives the preliminary design information for four chemical processes: dimethyl ether, acrylic acid, acetone, and heptenes production. This information is used in many of the end-of-chapter problems in the book. These processes can also be used as the starting point for more detailed analyses, for example, optimization studies. Other projects are included on the CD accompanying this book. The reader (faculty and students) is also referred to our web site athttp://www2.cemr.wvu.edu/~wwwche/publications/projects/index.html, where a variety of design projects for sophomore- through senior-level chemical engineering courses is provided. There is also a link to another web site that contains environmentally related design projects. For a one-semester design course, we recommend including the following core: Section 1--Chapters 1 through 4 Section 3--Chapters 9, 10, and 11 Section 5--Chapters 21 and 22 Section 6--Chapters 26 and 27 For programs in which engineering economics is not a prerequisite to the design course, Section 2 (Chapters 5Ð8) should also be included. If students have previously covered engineering economics, Chapters 12 and 13 covering optimization and pinch technology could be substituted. For the second term of a two-term sequence, we recommend Chapters 14 through 18 (and Chapters 12 and 13 if not included in the first design course) plus design projects. If time permits, we also recommend Chapter 19 (Regulating Process Conditions) and Chapter 20 (Process Troubleshooting) as these tend to solidify as well as extend the concepts of Chapters 14 through 18, that is, what an entry-level process engineer will encounter in the first few years of employment at a chemical process facility. For an environmental emphasis, Chapter 23 could be substituted for Chapters 19 and 20; however, it is recommended that supplementary material be included. We have found that the most effective way both to enhance and to examine student progress is through oral presentations in addition to the submission of written reports. During these oral presentations, individual students or a student group defend their results to a faculty panel, much like a graduate student defends a thesis or dissertation. As design is at its essence a creative, dynamic, challenging, and iterative activity, we welcome feedback on and encourage experimentation with this design textbook. We hope that students and faulty will find the excitement in teaching and learning engineering design that has sustained us over the years. Excerpted from Analysis, Synthesis, and Design of Chemical Processes by Richard Turton, Richard C. Bailie, Wallace B. Whiting, Joseph A. Shaeiwitz All rights reserved by the original copyright owners. Excerpts are provided for display purposes only and may not be reproduced, reprinted or distributed without the written permission of the publisher.