STRUCTURE OF DISTILLATION REGIONS FOR MULTICOMPONENT AZEOTROPIC MIXTURES

Geometric methods for the conceptual design of nonideal and azeotropic distillation systems have focused primarily on three-and four-compone nt mixtures. A generalization of geometric methods that does not rely on visualization and gives a completely equation-based approach to det ermine the structure of distillation regions for homogeneous mixtures is described. This method is useful for mixtures with a large number o f components, provided a vapor-liquid equilibrium model is available T he approach is applied to assess feasibility and alternative separatio ns in several examples, including a five-component mixture with nine a zeotropes and a six-component mixture with seven azeotropes. These met hods can be used to rapidly generate process alternatives, and the exa mples demonstrate that there can be a surprising number of these alter natives for the distillation of azeotropic mixtures.