Novel energy saving and economic extractive distillation process via integrating two-feed preheating strategy and heat pump vapor recompression

In this article, two-feed preheating strategies and heat pump vapor recompression are used to improve the thermodynamic efficiency and economic performance of extractive distillation. The separation process of methanol and acetone is used as a case study to accomplish this research. We find that two-feed preheating strategies are more efficient and have much less waste heat fraction removed by the condenser than one-feed preheating strategies. In the two-feed method, 3.86% of heat input to feed is removed while 36.86% of heat input to feed is removed by the condenser in one-feed. Two-feed preheating strategies can achieve more TAC reduction (22.28%) and thermodynamic efficiency (7.644%) than one-feed preheating strategies (19.15% /7.056%). The application of vapor recompression further enhances the energy-saving and thermodynamic efficiency of two-feed. In addition, the optimal vapor ratio in two-feed preheating strategies exists. The optimal vapor ratio is 0.7 and in this situation 52.46% improvement in thermodynamic efficiency and 35.15% energy saving can be achieved in comparison with the original extractive distillation process.

Automated summary

In this article, two-feed preheating strategies and heat pump vapor recompression are used to improve the thermodynamic efficiency and economic performance of extractive distillation. The case study of methanol and acetone separation process shows that two-feed preheating strategies are more efficient and have less waste heat fraction removed by the condenser than one-feed preheating strategies. The application of vapor recompression further enhances the energy-saving and thermodynamic efficiency of the two-feed method. The optimal vapor ratio of 0.7 in two-feed preheating strategies leads to significant improvements in thermodynamic efficiency (52.46%) and energy savings (35.15%) compared to the original extractive distillation process.