Page 8 - Gas Purification 5E

The first four editions of Gas Purijication were authored by Arthur L. Kohl and Fred C.
Riesenfeld. hh. Riesenfeld died shady after publication of the fourth edition in 1985. His
considerable technical contributions and warm friendship will be sorely missed.
The present team of authors has endeavored to completely overhaul and update the text for
publication as this fifth edition of Gas Punjication. Three new chapters have been added to
cover the rapidly expanding fields of NO, control (Chapter IO), absorption in physical sol-
vents (Chapter 14), and membrane permeation (Chapter 15). All other chapters have been
expanded, revised, and rearranged to add new subject matter, delete obsolete material, and
provide increased emphasis in areas of strong current interest. Examples of major additions
to existing chapters are the inclusion of new sections on liquid hydrocarbon treating (Chapter
2), Claus plant tail gas treating (Chapter 8), biofilters for odor and volatile organic com-
pound (VOC) control (Chapter 12), thermal oxidation of VOCs (Chapter 13), and sulfur
scavenging processes (Chapter 16).
Because of the growing importance of air pollution control, the coverage of gas purifica-
tion technologies that are applicable in this field, such as SO2, NO,, and VOC removal, has
been expanded considerably. On the other hand, the use of ammonia for H2S and COz
removal and the removal of ammonia from gas streams represent technologies of decreasing
importance, primarily because of the declining use of coal as a source of fuel gas. Discus-
sions of these two subjects have, therefore, been combined into a single chapter (Chapter 4).
Organization of the text represents a pctical compromise between an arrangement based
on unit operations or process similarities and one based on impurities being removed. Thus,
Chapters 12 and 15 cover the operations of adsorption and membrane permeation, respec-
tively, and the use of these technologies for the removal of a wide variety of impurities;
while Chapters 7 and 10 cover single impurities (SOz and NO,, respectively) and their
removal by a number of different processes. Consideration is also given to the industrial
importance of the technologies in the allocation of chapters; as a result, two chapters (Chap-
ters 2 and 3) are devoted to the use of amines for the removal of H2S and COz, while only
one, rather short chapter (Chapter 6) covers the use of water for the absorption of gas impuri-
ties of any type.
The aim of this book is to provide a practical engineering description of techniques and
processes in widespread use and, where feasible, provide sufficient design and operating data
to permit evaluation of the processes for specific applications. Limited data on processes that
were once, but are no longer commercially important, are also presented to pvide an histor-
ical perspective. Subject matter is generally limited to the removal from gas streams of gas-
phase impurities that are present in relatively minor proportions. The removal of discrete sol-
id or liquid particles is not discussed, nor are processes that would more appropriately be
classified as separation rather than purification.
A generalized discussion of absorption is provided in Chapter 1 because this unit opera-
tion is common to so my of the processes described in subsequent chapters. Discussions of
other unit operations employed in gas purification processes, such as adsorption, catalytic