Acta Cryst. (1997). A53, 527-528
An explosion of papers developing the design-oriented theories of industrial crystallization over the past decades has created a need to summarize what has been accomplished. Thus, several textbooks on this topic have appeared recently that merit mention. These include the completely rewritten third edition of Crystallization, by J. W. Mullin (Butterworth-Heinemann, Oxford, 1993), an extensive and instructive general survey of the field of crystallization; The Kinetics of Industrial Crystallization, by J. Nývlt, O. Sohnel, M. Matuchova & M. Broul (Elsevier, Amsterdam, 1985), dealing mainly with the effects of various parameters on the kinetics of individual steps in the crystallization process; Design of Crystallizers, also by J. Nývlt (CRC Press, Boca Raton, 1992), focuses on the application of kinetics to develop the relationships between the volumes of various types of crystallizer and the resulting product crystal size. Two other books, Crystallization Technology Handbook, edited by A. Mersmann (Marcel Dekker, New York, 1995), and Precipitation, edited by O. Sohnel & J. Garside (Butterworth-Heinemann, Oxford, 1992), summarize, respectively, our knowledge of design-oriented processes and the role of thermodynamics in the precipitation of less soluble compounds. Now comes this new book by N. S. Tavare, the main thrust of which is the application of mathematical methods to modelling the crystallization process.
The book has twelve chapters. Chapter 1 is a brief introduction to the problem. Chapter 2 deals with phase equilibria in various systems and with the materials balance of crystallization; the chapter is a good survey of the shapes of phase diagrams but, surprisingly, provides almost no hints as to their mathematical description and their practical uses. Chapter 3 gives a very brief survey of the fundamental concepts of nucleation and crystal growth and of the fundamental equations used for chemical-engineering descriptions of the processes. Most interesting are tables showing the range of typical kinetic parameters, with most probable estimates. However, the effects of several other parameters (e.g. solution purity, agitation, temperature etc.) are not mentioned. Chapter 4 is devoted to crystal-size distribution; important, because that is the basis of most modelling and design methods. The survey of the various distribution functions is very brief, with only a weak emphasis on the advantages of gamma-distribution. The main value of this chapter is in its general presentation of the population balance problem and methods of solving it. Chapter 5 illustrates methods of process representation, of operating modes of batch crystallizers, and of process analysis. This chapter, and the related Chapter 6, on characterization of crystallization kinetics from batch experiments, are certainly of great value for those research workers dealing with batch crystallization and, together, the two chapters occupy about 100 pages. Chapter 7 deals mainly with precipitation processes and, perhaps a little inconsistently, with other processes such as Ostwald ripening and agglomeration.
Chapter 8, devoted to continuous crystallizers, treats in the usual way the population balance for an ideal case, as well as for size-dependent growth rate and growth-rate dispersion. Of particular interest are the subchapters describing the effects of the size-dependent residence time distribution and the dynamics and control of continuous crystallizers. A short paragraph deals with the plug-flow crystallizer and, again, there is a paragraph on agglomeration. Chapter 9 describes the effect of growth-rate dispersion and methods of analyzing that phenomenon. Chapter 10, on mixing, is very important as, in many cases, mixing has an enormous effect on crystallization. This chapter also includes remarks on fluid-bed crystallizers and series of agitated vessels.
Chapter 11 deals with crystallizer design and operation. It is relatively brief and, besides some general remarks, contains just a few design illustrations using published examples from the literature. The concluding Chapter 12 briefly describes other crystallization techniques, such as adductive and extractive crystallization, the use of hydrotropic additives, and freeze and emulsion crystallization. A few comments are also made on encrustations and modification of crystal habit.
The book contains a number of experimental results and numerous solved examples. In addition, it provides a good literature survey, though in many cases providing only references without detailed descriptions of the respective methods. This is understandable, however, as a more detailed treatment would have enormously expanded the book's size. The book can be recommended as an extremely useful tool for process engineers, technologists and researchers in the field, and to advanced-level students of chemical engineering.
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