Efficient Separation of Acetonitrile/Ethanol/Water Using Ionic Liquid: Molecular Thermodynamic and Process Intensification

Abstract

To address the challenging separation of the ternary acetonitrile/ethanol/water mixture, this study proposes a novel extractive distillation process integrated with ionic liquid and multienergy coupling. 1-Butyl-3-methylimidazolium acetate was identified as the optimal entrainer using the COSMO-RS model, and the separation mechanism was elucidated through quantum chemical calculation and molecular dynamics simulations. Process intensification technologies were integrated into the basic process, followed by multiobjective optimization. Compared with the conventional process, the optimal preheated feedstock, heat integrated, and organic rankine cycle extractive distillation process achieves a 20.70% reduction in total annual cost, a 47.68% decrease in energy consumption and acid gas emissions, and a 62.99% improvement in thermodynamic efficiency. Furthermore, the global warming potential and acidification potential are reduced by 30.79% and 27.39%, respectively, achieving a synergistic enhancement of economic and environmental benefits.