Pressure-Swing Homogeneous Azeotropic Distillation Combined with Heat Pump and Heat Integration Technologies for the Recovery of Ethanol, Toluene, and Acetonitrile: Multiobjective Optimization and Comprehensive Performance Evaluation

Abstract Ethanol (EtOH), toluene (TOL), and acetonitrile (ACN) often coexist in industrial wastewater and form a homogeneous azeotropic system that is difficult to separate. In this work, a pressure-swing homogeneous azeotropic distillation process was developed and intensified with heat pump and heat integration strategies. Multiobjective optimization was used to balance economic, environmental, and energy performance indicators. Compared with the base process, the optimized heat pump and heat-integrated configuration reduced total annual cost, gas emissions, and energy consumption while maintaining product-purity requirements. The results demonstrate that coupling pressure-swing distillation with heat recovery provides an effective route for sustainable recovery of ethanol, toluene, and acetonitrile from azeotropic wastewater in industrial solvent-recycling applications.