Preface
In the 21st century, separations remain as important, if not more important, than in the previous century. The development of new industries such as biotechnology and nanotechnology, the increased importance of removing traces of compounds, and the probable need to recover and sequester carbon dioxide have brought new separations to the fore. Chemical engineers must understand and design new separation processes such as membrane separations, adsorption, and chromatography in addition to the standard equilibrium-staged separations, including distillation, absorption, and extraction. Since membrane separations, adsorption, chromatography, and ion exchange are included, I changed the title of the second edition from Equilibrium-Staged Separations to Separation Process Engineering to reflect this broader coverage. The new title has been retained for the third and fourth editions with the addition of a subtitle, Includes Mass Transfer Analysis, which reflected the addition of Chapter 15.
The second edition was unavoidably longer than the first, the third edition was longer than the second, and, of course, the fourth edition is still longer. The most important addition to the fourth edition is the new Chapter 17, “Crystallization from Solution.”
Additional extensive changes include: extending Chapter 5 to ternary stage-by-stage calculations with bubble- or dew-point calculations on every stage; inclusion of fraction collection and multicomponent calculations for simple batch distillation in Chapter 9; new equipment costs and addition of a brief review of heat exchanger design in Chapter 11; new mass transfer analysis sections on numerical solution for variable diffusivity and mass transfer to expanding or contracting objects including ternary mass transfer in Chapter 15; increased coverage of pervaporation in Chapter 18; and inclusion of six new Aspen Chromatography labs in Chapter 19.
All of the chapters have many new homework questions and problems. More than 300 new questions and problems are included. Since all of the problems were created and solved as I continued to teach this material, a Solutions Manual is available to professors who adopt this textbook for their courses. A number of spreadsheet problems have been added, and the answers are provided in the Solutions Manual.
Since process simulators are used extensively in commercial practice, I have continued to include process simulation examples and homework problems throughout the text. I now teach the required three-credit, junior-level separations course at Purdue as two lectures and a 2-hour computer lab every week. The computer lab includes a lab test to assess the ability of the students to use the simulator. Although I use Aspen Plus as the simulator, any process simulator can be used. All of the Aspen Plus labs have been updated to Version 8.8. The appendices to Chapters 2, 4, 5, 15, 17, and 18 have Excel spreadsheets, some of which use Visual Basic programs. I chose to use spreadsheets instead of a higher-level mathematical programs because spreadsheets are universally available. The appendix to Chapter 19 includes expanded, tested instructions for operation of the commercial Aspen Chromatography Simulator—Version 8.8.
The material in the fourth edition has been extensively tested in the required junior-level courses on separations at Purdue University and at the University of Canterbury, Christchurch, New Zealand. Chapters 1 to 14 can be taught to sophomores, and all of the material is suitable for seniors. The book is too long to cover in one semester, but more complete coverage is feasible in two quarters. If mass transfer is included, this text could easily be used for a two-semester sequence. If a single, three-credit semester course is available for separations, topics must be selected. One option is to use Chapters 1 to 14 for the required course and Chapters 15 to 19 for an elective course. Several course outlines are included in the Solutions Manual. Instructors may register at www.pearsonhighered.com for access to this book’s Solutions Manual.