Abstract

Separations process synthesis is the invention of conceptual flowsheets for the separation of multicomponent mixtures. Systematic methods are now available to aid in the generation of separations schemes for analysis and evaluation. For fluid systems, distillation remains the separation method of choice. This article describes heuristic methods for generating alternative distillation schemes for nonazeotropic mixtures, thermal coupled distillations, as well as a more general method for generating separation schemes for nonideal liquid mixtures including systems involving azeotropes. This latter method makes use of the residue curve map representation for vapor–liquid equilibria and introduces the concepts of strategic and opportunistic operations to systematically overcome difficulties introduced by azeotropes and other nonidealities. Mention is also given to separation synthesis methods for reactive separations.