Page 16 - Separation process engineering

Preface

In the twenty-first 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 were 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 edition with the addition of a subtitle,
Includes Mass Transfer Analysis, which reflects the addition of Chapter 15.

The second edition was unavoidably longer than the first, and the third edition is longer than the second.
The first major addition to the third edition is the extensive Chapter 15, which includes mass transfer and
diffusion. Both the Fickian and Maxwell-Stefan approaches to diffusion are covered in detail with
examples and homework assignments. The old Chapter 15, which applied mass transfer techniques to
equilibrium-staged separations, is now Chapter 16 with the removal of Section 15.1, which is now

incorporated in the new Chapter 15.
The second major change is a much more extensive analysis of liquid-liquid extraction. Chapters 13 and
14 in the second edition both covered extraction, washing, and leaching. In the third edition, the material
is reorganized so that Chapter 13 covers only extraction and Chapter 14 covers washing and leaching. In
addition to the McCabe-Thiele, triangle, and computer-simulation analyses of extraction, Chapter 13 now
includes a section on the detailed design of mixer-settlers and a shorter section on the design of Karr
columns. Mass transfer analysis of liquid-liquid extraction systems has been added to Chapter 16.

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 at Purdue University, a Solutions Manual is available to professors who adopt this textbook for
their course. 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 two-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. Chapters 2, 6, 8, 10, 12,
13, and 16 include appendices that present instructions for operation of Aspen Plus. The appendices to
Chapters 2, 4, 5, 15, and 17 have Excel spreadsheets, some of which use Visual Basic programs. I chose
to use spreadsheets instead of a higher-level mathematical program because spreadsheets are universally
available. The appendix to Chapter 18 includes brief instructions for operation of the commercial Aspen
Chromatography simulator—more detailed instruction sheets are available from the author:

wankat@purdue.edu.
The material in the third edition has been extensively tested in the required junior-level course on
separations at Purdue University. Although I teach the material at the junior level, Chapters 1 to 14 could
be taught to sophomores, and all of the material is suitable for seniors. The book is too long to cover in
one semester, but almost complete coverage is probably feasible in two quarters. If mass transfer is

included, this text could easily be used for a two-semester sequence. Many schools, including Purdue,