Economical process design of reactive-extractive distillation combining variable pressure and heat integration for separating a ternary azeotropic mixture.

Research and development of environmentally friendly processes that can generate significant profits has always been a focus of attention in pharmaceutical and chemical fields. In this study, a novel reactive-extractive pressure-swing distillation (REPSD) process was designed to separate tetrahydrofuran (THF)-methanol-water (TMW) ternary azeotropic mixtures. Ethylene oxide (EO) is reacted with water to form ethylene glycol (EG) in a reactive distillation (RD) column, which removes the water from the mixture. Then, the THF-methanol (TM) mixture is separated by extractive distillation (ED) and pressure-swing distillation (PSD). A multi-objective genetic algorithm (MUOGA) with total annual cost (TAC) and total capital cost (TCC) as objective functions, along with heat integration techniques were used to optimise the designed REPSD process. Optimal operating conditions to achieve maximum economic benefits were obtained for the process. Subsequently, the environmental benefits of the process were evaluated. The results showed that the proposed REPSD with heat integration can significantly reduce the TAC and CO 2 emissions by 29.1 and 26.9 %, respectively, compared to existing optimal heat integration extractive distillation (HIED) processes. This study provides a new perspective on the separation and purification of ternary azeotropic mixtures. [Display omitted] • A novel and energy-saving REPSD process for the separation of THF-methanol-water mixtures was designed. • The water was removed by reacting with EO for obtaining the valuable by-product EG. • The designed REPSD processes were optimised through multi-objective genetic algorithm and heat integration. • The TAC and CO 2 emissions were significantly reduced by 29.1 % and 26.9 %, respectively. [ABSTRACT FROM AUTHOR]