PRocess control Chapter reaction curve

Having a set of a,t) data available, a graph was prepared to illustrate the type of plot that can be expected when a reaction follows an Avrami-Erofeev rate law. The result is shown in Figure 7.2, and the sigmoidal curve is characteristic of a reaction that follows a nucleation rate law. In Chapter 2, it was shown that a sigmoidal rate plot results from autocatalysis, but for reactions in the solid state such plots are more likely to indicate that the reaction is controlled by some type of nucleation process. 

Sundmacher and Qi (Chapter 5) discuss the role of chemical reaction kinetics on steady-state process behavior. First, they illustrate the importance of reaction kinetics for RD design considering ideal binary reactive mixtures. Then the feasible products of kinetically controlled catalytic distillation processes are analyzed based on residue curve maps. Ideal ternary as well as non-ideal systems are investigated including recent results on reaction systems that exhibit liquid-phase splitting. Recent results on the role of interfadal mass-transfer resistances on the attainable top and bottom products of RD processes are discussed. The third section of this contribution is dedicated to the determination and analysis of chemical reaction rates obtained with heterogeneous catalysts used in RD processes. The use of activity-based rate expressions is recommended for adequate and consistent description of reaction microkinetics. Since particles on the millimeter scale are used as catalysts, internal mass-transport resistances can play an important role in catalytic distillation processes. This is illustrated using the syntheses of the fuel ethers MTBE, TAME, and ETBE as important industrial examples. 

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