Economic, entropy generation and environmental analysis of separation of high-concentration azeotropic mixtures by an innovative extractive distillation configuration based on multi-objective optimization

•An innovative extractive distillation process combining prefractionator with extractive distillation column for separating high-concentration azeotropic mixtures.•Multi-objective optimization is conducted with the minimization of TAC, CO2 emissions, and entropy generation as the objective functions.•Entropy generation analyses highlights areas of irreversibility.•Heat pump technology and heat integration technology have obvious energy-saving effects. The process design and optimization of separating azeotropic mixtures by extractive distillation (ED) has been a hot problem in recent years. Conventional ED process often faces challenges of high energy consumption and high costs when dealing with azeotropic mixtures containing a high content of a certain component. Therefore, an energy-efficient innovative three-column extractive distillation process (ITCED) that is capable of simultaneously performing preconcentration and extractive distillation functions within a complex distillation column for separating ethyl acetate/n-propanol/water azeotropic mixture containing a large amount of n-propanol is developed. Multi-objective optimization is conducted with the minimization of total annual cost (TAC), CO2 emissions, and entropy generation as the objective functions. According to the optimization results, the ITCED process exhibits substantial advantages compared to the conventional three-column extractive distillation process (TCED), with reductions of 34.95% in TAC, 35.84% in CO2 emissions, and 38.91% in entropy generation. Subsequently, heat pump and heat integration technologies are employed to enhance the ITCED process for the further energy conservation. As a result, compared with the TCED process, the DHP-HI-ITCED process achieves savings of 48.18% in TAC, 67.5% in CO2 emissions and 72.96% in entropy generation.