Multizone configurations

In this chapter, the problem of optimization of multizone configurations will be dealt with. When talking about a zone, we consider a thin active zone in which perfect mixing is assumed. Typically, thin catalyst zones are used in temporal analysis of products (TAP) studies, but other types of experiments involving thin active zones are also conceivable. 

Chapter 8 provides original results for optimal configurations of multizone reaction-diffusion reactors, and compares these with results for a cascade of reactors known from the literature. 

Since the same will happen in Reactor 2, in the end the ratio of polypropylene to ethylene-propylene copolymer per particle exiting Reactor 2 will also vary widely, which may be undesirable in some applications. Some of the reactor configurations shown in Figure 8.35 can reduce this phenomenon, particularly the configuration adopted for the gas-phase horizontal reactor, because the residence time distribution of this reactor is the equivalent to about three to four CSTRs in series. (Remember that the residence time of an infinite series of ideal CSTRs is that of a plug-flow reactor.) A more recent solution for this problem, in fact a completely new alternative to tandem reactor technology, is the multizone reactor that will be described in more detail below (see Section 8.6.4). 

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