Control of Extractive Distillation and Partially Heat-Integrated Pressure-Swing Distillation for Separating Azeotropic Mixture of Ethanol and Tetrahydrofuran

Abstract

Dynamic controls of an extractive distillation (ED) process and a partially heat-integrated pressure-swing distillation (PHIPSD) process for separating a mixture of 50 mol % ethanol and 50 mol % tetrahydrofuran are investigated. Comparisons between the control structures of the two distillation processes are made. The results show that PHIPSD has advantages of economic savings and control compared with the ED process. In addition, some control structures of PHIPSD for feed streams with different composition and some comparisons between the performances of the control structures are also studied. It is concluded that the feed composition mainly impacts the dynamic control structures of PHIPSD through the different combinations of auxiliary heat exchanger and that a composition controller can improve the control performances.