Kinetic Effects on Attainable Products

As shown above, reaction kinetics have a significant influence on RD process performance in binary mixtures and the same is true for multicomponent mixtures. In the following, the attainable products of kinetically controlled RD processes are analyzed, first for ideal ternary mixtures, then for non-ideal ternary mixtures occurring in industrially important fuel ether synthesis, and finally for an extremely non-ideal system with potential liquid-phase splitting. In all cases, reversible reactions of type A + B o C are considered. 

As a common analysis tool, residue curve mapping (RCM) is well established. Fien and Liu [4] published a comprehensive review of the synthesis and shortcut design of non-reactive separation processes based on RCMs. Barbosa and Doherty [5] developed RCMs for RD processes with single chemical equilibrium reaction. Ung and Doherty [6] extended this method to systems with multiple equUibrium reactions. 

The determination of the singular points appearing in these maps yields important information about the attainable bottom product compositions in real counter-current columns. However, as shown by Chadda et al. [3], both the distillate and the bottom product compositions can be better obtained as singular points of a reactive enriching flash cascade or a stripping flash cascade, respectively. As will be shown, singular point analysis can also provide valuable information about the role of interfacial mass-transfer resistances in RD processes. 

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