Introduction to Simplified Design Philosophy

Multiphase reactions may involve gas-liquid, gas-liquid-solid (solid as catalyst or reactant), liquid-liquid, liquid-liquid-solid reactions, etc. The reactions may vary from very slow to very fast, endothermic to highly exothermic. Based on the reaction characteristics, different types of multiphase reactors are used in industrial practice. A number of texts deaUng with design of multiphase reactors are available (Satterfield 1970 Shah 1979 Ramachandran and Chaudhari 1983 Westerterp et al. 1988 Deckwer 1992). Considerable information on theoretical, hydrodynamics, and mass transfer aspects of different multiphase reactors has become available since the publication of the above texts. This recent information is likely to allow rational, simple and yet reliable designs of many industrially important multiphase reactors. In this book, different types of multiphase reactors falUng under two categories—(1) gas-liquid and (2) gas-liquid-solid— are considered. The basic aim is to provide user-friendly, simple, and reasonably accurate design procedure for each multiphase reactor. 

Multiphase systems of the above type have at least one free interface, that is, Uquid film/drops/bubbles. The behavior of such a discrete dispersed phase is very complex. The fihns/drops/bubbles can break/coalesce repeatedly when undergoing turbulent in motion both time and space. Several factors such as the flow pattern and turbulent shear stress, the nature (coalescing/no coalescing), etc. affect the size of the drops/bub-bles. The transport of mass from/to the surrounding liquid is affected by the turbulence 

Design of Multiphase Reactors, First Edition. Vishwas Govind Pangarkar. 

It is precisely this approach that is adopted in this book. The use of blind empiricism so heavily criticized by our peers is resorted to only when unavoidable. This book considers the different multiphase reactors separately while retaining the basic objective mentioned earlier. 

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