Eco-efficient heat-integrated extractive distillation process using ionic liquid as entrainer for ethyl acetate-isopropyl alcohol-water mixture

Ethyl acetate-isopropyl alcohol-water is a common ternary mixture in pharmaceutical and chemical industries, containing multiple binary minimum azeotropes. Highly efficient separation for this mixture is of great significance to reduce environmental risk, recover valuable resource and maintain eco-sustainability. In this work, various enhanced extractive distillation processes using ionic liquid (IL) as entrainer are compared with conventional extractive distillation process (CED) in terms of the reductions of cost, energy and carbon emissions. First of all, ethylene glycol (EG) and 1-ethyl-3-methylimidazolium acetate ([BMIM][OAC]) as the most promising conventional and IL entrainers are screening out through quantum chemistry calculation based on COSMO-SAC model. Secondly, two methods of improving energy efficiency such as differential pressure heat integration and divided-wall column are applied to the CED process. Finally, the resulting six configurations are optimized by simulated annealing algorithm, taking minimum total annual cost (TAC) as goal, and subsequently evaluated from four aspects of TAC, annual capital cost (ACC), annual operating cost (AOC) and CO2 emission. The results show that the new heat-integrated extractive distillation configuration with [BMIM][OAC] as entrainer, known as EDHI-IL is the best solution for ecological efficiency. As compared to the CED process, TAC, ACC, AOC and CO2 emission of this process are reduced by 38.86%, 36.51%, 41.41% and 41.36%, respectively.