Economic and entropy production evaluation of extractive distillation and solvent-assisted pressure-swing distillation by multi-objective optimization

Extractive distillation (ED) and solvent-assisted pressure-swing distillation (SA-PSD) are both special distillation processes that perform good at separating pressure-insensitive azeotropes. However, few reported studies have compared the performance of the two processes. In this paper, ED processes with N-methylpyrrolidone (NMP) and dimethlac-etamide (DMCA) as entrainer, SA-PSD process with isopropyl-alcohol (IPA) as solvent and SA-PSD process with partial heat integration (PHI-PSD) are proposed to achieve high purity separation of a mixture of cyclohexane/2-butanol system. The optimal operating conditions of the processes are obtained after optimizing with NSGA-II algorithm when total annual cost (TAC) and the entropy production of process are set as objectives. The optimal results show that the optimal PHI-PSD process has lower TAC by 28.7% and the lower entropy production by 39.5% than the optimal SA-PSD process while the ED process with NMP as entrainer has lower TAC by 50.9% and the lower entropy production by 56.1% than the optimal SA-PSD process. The optimal results show that the ED process with NMP as entrainer has the best economic and thermodynamic efficiency among the four proposed processes in this paper. (c) 2023 he Chemical Industry and Engineering Society of China, and Chemical Industry Press Co., Ltd. All rights reserved.