Exploring Exergy Performance in Tetrahydrofuran/Water and Acetone/Chloroform Separations

Abstract

Distillation is significantly influenced by energy costs, prompting a need to explore effective strategies for reducing energy consumption. Among these, heat integration is a key approach, but evaluating its efficiency is paramount. Therefore, this study presents exergy as an energy quality indicator, analyzing irreversibility and efficiencies in tetrahydrofuran/water and acetone/chloroform distillations. Both systems have equimolar feed streams, yielding products with 99.99 mol% purity. The simulations are performed using Aspen Plus™, enabling evaluation at the column level, as a standalone process, or from a lean perspective that considers integration opportunities with other plants. The results show that, despite anticipated energy savings from heat integration, economic viability depends on pressure sensitivity. The results demonstrate that heat-integrated extractive distillation for acetone/chloroform raises utility energy consumption. Exergy calculations comparing standalone and total site integration reveal the variation in distillation efficiency with operation mode. Global exergy efficiency in both extractive and pressure-swing distillation depends on the fate of condenser duty. In heat-integrated extractive distillation, global exergy efficiency drops from 8.7% to 5.7% for tetrahydrofuran/water and 11.5% to 8.3% for acetone/chloroform. Similarly, heat-integrated pressure-swing distillation sees global exergy efficiency decrease from 34.2% to 23.7% for tetrahydrofuran/water and 9.5% to 3.6% for acetone/chloroform, underscoring the nuanced impact of heat integration, urging careful process design consideration.