Sustainable wastewater treatment via extractive distillation process with ionic liquid as entrainer for the separation of ethyl acetate/isopropanol/water

To recycle isopropanol and ethyl acetate from wastewater by extractive distillation, 1-butyl-3-methylimidazolium acetate ([BMIM][OAc]) is considered to be an appropriate entrainer by comparing with ethylene glycol on VLE diagram and σ-Profiles, respectively. Then, the extractive distillation processes with [BMIM][OAc] as entrainer are proposed. Since the degradation temperature of [BMIM][OAc] requires the entrainer recovery section of processes to operate under high vacuum, one-stage evaporator and one stripping column configuration is determined to recycle entrainer [BMIM][OAc]. After optimizing the IL processes, the heat integration technology is applied to the optimized processes. Compared conventional extractive distillation process with EG as entrainer, the heat integration assisted IL process with appropriate entrainer recovery configuration which uses IPA as stripping agent can reduce 24.76% of TAC, 45.64% of energy consumption and 45.52% of gas emission.