低共熔溶剂萃取精馏分离乙醇-水共沸物的研究

Extractive distillation of ethanol-water azeotrope with low transition temperature mixtures

分别以氯化胆碱/甘油(摩尔比为1∶2)低共熔溶剂(Reline)和乙二醇为萃取剂,对乙醇脱水萃取精馏过程进行模拟研究,并以最小年度总费用TAC为目标函数,对2种工艺流程进行优化,得到了最优的操作条件。结果表明,与乙二醇萃取精馏流程相比,Reline萃取精馏中萃取剂用量降低20%,能耗费用降低21. 68%,年度总费用TAC降低19. 66%,具有明显的节能优势。对Reline常规萃取精馏进行节能研究,发现对该流程进行换热网络优化后,可使年总费用TAC下降7. 95%;而隔壁塔并不能降低整个过程的年总费用。

The separation of ethanol and water by extractive distillation is designed and simulated by Aspen Plus with low transition temperature mixtures ( LTTMs,choline chloride/urea = 1 ∶ 2) and ethylene glycol as extractant,respectively.Also,the minimal total annual cost( TAC) is used as the objective function to find the optimal design for these two extractive distillation systems.The results show that compared with ethylene glycol process,the usage amount of extractant in LTTMs process is 20% less,the operation cost is 21. 68% lower and the total annual cost is 19. 66% lower,indicating an economic advantage.In order to reduce TAC of the LTTMs extractive distillation process,various measures are taken.After the heat exchange network is optimized,TAC can be reduced by 7. 95%.However,the extractive dividing wall column distillation process cannot be helpful to reduce TAC by using such measurement.The results provide a design reference and theory basis for the industrial design of extractive distillation process to separate ethanol and water mixture.