Economic, thermodynamic and environmental analysis of separating high-concentration azeotropic mixture by a novel extractive dividing wall column configuration combining preconcentration and extractive distillation based on multi-objective optimization

This research proposes a novel and efficient scheme for separating high-concentration azeotropic mixture, specifically addressing the economic efficiency and energy consumption challenges present in conventional extractive distillation. An innovative extractive dividing wall column configuration with a combined distillation column (EDWC-CDC) using dimethyl sulfoxide (DMSO) as the entrainer is introduced, aiming at separating ethyl acetate/ethanol/cyclohexane mixture with high cyclohexane content. The EDWC-CDC configuration integrates a preconcentration column and an extractive distillation column into a combined distillation column, while simultaneously integrating an extractive distillation column and an entrainer recovery column into a dividing wall column. A multi-objective optimization strategy is implemented, with the minimization objectives including total annual cost (TAC), entropy production, and CO2 emissions. The optimization results indicate that compared to the conventional extractive distillation configuration (CED), the EDWC-CDC configuration presents significant advantages, with reductions of 26.72 % in TAC, 38.30 % in entropy production, and 35.40 % in CO2 emissions. Furthermore, the potential of applying heat pump and heat integration technologies into the EDWC-CDC configuration is explored. Specifically, compared to the CED configuration, the heat pump and heat integration assisted extractive dividing wall column configuration with a combined distillation column - scheme II (EDWC-CDC-HPHI-II) configuration achieves savings of 32.40 % in TAC, a decrease of 62.23 % in entropy production, and a reduction of 57.84 % in CO2 emissions.