Comparison of Ionic Liquids and Organic Solvent Effects on the Separation of Water–Dimethyl Carbonate–Ethanol by Extractive Distillation based on Mechanism Research and Process Simulation

As a highly effective technique for azeotrope separation, extractive distillation (ED) has garnered widespread recognition. The rational selection of extractants and the green, energy-efficient design of processes are the core of separation technology. Based on the COSMO theory, four extractants ([BMim][AC], [EMim][DEP], DMSO, and EG) were preliminarily screened by the COSMOThermX software. Then, detailed investigations were carried out to elucidate the extraction mechanisms of distinct extractants in this system. Through ESP, AIM, and interaction energy analysis, results confirmed [BMim][AC] as the extractant with the optimal extraction performance. Then, different ED processes were designed using Aspen with [BMim][AC] and DMSO as the extractants, respectively. The optimal design scheme of the process was successfully derived through multiobjective optimization (MOO). Additionally, heat-integration optimization was carried out on all ED processes. The TAC and the gas emissions of the HIEPSD process using [BMim][AC] as the extractant were 1.2989 × 10 6 $/Y and 1579.32 kg/Y, which decreased by 18.78% and 18.95% compared to the EPSD ([BMim][AC]) process, demonstrating that the HIEPSD ([BMim][AC]) process delivered optimal outcomes regarding economic efficiency and environmental friendliness.