Introducing a heat integration method to reduce energy consumption and pollutant emission in the extractive distillation process

This paper evaluates separation of a minimum boiling homogeneous azeotropic mixture using the extractive distillation process. To alter the vapor-liquid equilibrium of the water-ethanol azeotropic mixture, a glycerol entrainer with a boiling point higher than those of water and ethanol was used. Feed-splitting was used for heat integration. In this method, the feed is split into two sections, where the bottom section is pre-heated through a hot stream, while the top section flows into the column without a temperature change. This reduces the heat duty of the reboiler, with the heat duty of the condenser remaining almost unchanged. To evaluate the proposed method, four different processes were accurately simulated in Aspen HYSYS V.۱۰. The proposed process was found to have ۱۹% lower energy consumption than extractive distillation without heat integration. Also, the optimized process resulted in a ۱۸.۶۴% reduction in carbon dioxide emission compared to the original process. This significant improvement demonstrates the effectiveness of heat integration in minimizing environmental impacts.

Keywords:

Extractive distillation , CO۲ emission , Heat integration , Minimum boiling azeotrope , Feed-splitting