Heat Integration of Pressure Swing Extractive Distillation for Separation of Minimum Boiling Azeotropic Mixture

This study evaluated heat integration of extractive distillation to separate the minimum boiling homogeneous azeotropic mixture of methanol and toluene. Triethylamine was used as the entrainer in the indirect separation of toluene and methanol as the bottom product of column 1 and the top product of column 2, respectively. This study implemented forward multi-effect heat integration and backward multi-effect heat integration. The feed flowed into the high-pressure column in the forward process, while the backward process drove the feed into the low-pressure column. The condenser of the high-pressure column was integrated with the reboiler of the low-pressure column in both processes. The backward multi-effect extractive distillation process showed the lowest energy consumption and thus represented the optimal process. It showed 48% lower energy consumption than extractive distillation without heat integration.