Scaleup of Multiphase Reactors

Other Cases In some cases, a reaction takes place in one of the phases in a multiphase reactor but not in the others. Obviously, it is critical to know the phase in which the reaction occurs. If the definition of the reaction rate is based on the total reactor volume, serious trouble wiU result when the ratio of the phases changes. The ratio of the phases generally will depend on variables such as the reactor dimensions, the intensity of mechanical agitation, and the feed rates and compositions of the various fluids. Therefore, difficulty is inevitable, especially on scaleup, if the reaction rate is misdefined. 

A number of successful devices have been in use for finding mass-transfer coefficients, some of which are sketched in Fig. 23-29, and all of which have known or adjustable interfacial areas. Such laboratoiy testing is reviewed, for example, by Danckwerts (Ga.s-Liquid Reac-tion.s, McGraw-Hih, 1970) and Charpentier (in Ginetto and Silveston, eds., Multiphase Chemical Reactor Theory, De.sign, Scaleup, Hemisphere, 1986). 

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