SYNTHESIS OF CRYSTALLIZATION-DISTILLATION HYBRID SEPARATION PROCESSES

A systematic method to synthesize crystallization-distillation hybrid separation processes is presented. Two classes of hybrids are identifi ed for binary mixtures. The first bypasses azeotropes and tangent pinc hes, while the second bypasses eutectics. Guidelines for flow-sheet se lection are proposed based on an analysis of simple eutectic, constant relative volatility systems. In addition, the hybrids are compared to both extractive and adductive crystallization in order to determine t he conditions under which solvent-based crystallization techniques out perform the proposed hybrid configurations. The method is extended to ternary mixture. The use of stream combination and complex distillatio n columns is also considered.