Design and control of an energy-efficient alternative process for separation of Dichloromethane-Methanol binary azeotropic mixture

Abstract

Design and control of an energy and cost efficient separation process is deduced amongst several evaluated separation alternatives for Dichloromethane-Methanol binary mixture. Separation process evaluation for this specific binary mixture has not received much attention in the open literature so far. In the present study, several other significant alternatives (Pressure swing distillation, Extractive distillation and Azeotropic distillation) for the separation of the mixture have been explored and compared with the single reported work published earlier wherein separation using pressure swing batch distillation method has been discussed. Steady state analysis reveals that out of these evaluated alternatives; Extractive distillation is the best method in terms of economics and energy efficiency. The TAC of the extractive distillation method (best amongst four alternatives studied including the published work of PSBD method) was found to be 27.62% less than that of the second best from the list, which is Pressure Swing Batch Distillation method (Heat integration variant). The saving by extractive distillation method will result in significant benefits based on the futuristic surge in compound annual growth rate in the production of Dichloromethane-Methanol. Further, a plantwide control structure is designed for the recommended extractive distillation flow sheet which is further evaluated for throughput and composition disturbances. The present study will be helpful in designing the real process plants for the separation of Dichloromethane-Methanol binary mixture.