萃取精馏分离乙酸乙酯、乙酸丙酯、乙醇和水体系工艺研究

Separating process of ethyl acetate,n-propyl acetate,ethanol and water by extractive distillation

乙酸乙酯、乙酸丙酯、乙醇和水体系彼此间都存在共沸,且存在三元共沸,很难通过普通精馏进行分离。利用Aspen Plus对萃取精馏法分离乙酸乙酯、乙酸丙酯、乙醇和水体系的工艺进行模拟,热力学模型为UNIFAC,并对该体系进行萃取精馏实验研究,利用萃取精馏实验数据对热力学模型进行修正,使模拟数据与实验数据吻合,相对误差小于7.5%。通过乙酸乙酯、乙酸丙酯、乙醇和水体系萃取精馏实验,详细研究了理论板数、溶剂比、回流比等因素对分离效果的影响,结合流程模拟数据,得出了该工艺的适宜条件：理论板数68~75,溶剂比5.8~6.5,回流为3.0~3.5。在适宜的工艺条件下,乙酸乙酯和乙酸丙酯的收率达到95%以上。

Ethyl acetate, propyl acetate, ethanol and water are azeotropic mixtures. Except several bina- ry azeotropes,ethyl acetate, ethanol and water are ternary azeotrope, so with propyl acetate, ethanol and water, which make the separation difficult. Process simulation of extractive distillation was carried out using ASPEN Plus with thermodynamic method of UNIFAC. Experiment was conducted and ex- perimental data was used to revise the thermodynamic model making it match well with experiment re- sult with relative tolerance of 7.5%. Effect of number of theoretical stages, solvent-to-feed ratio and reflux ratio were studied through experiment and process simulation. And appropriate operating condi- tion was acquired with theoretical stages of 68~75,solvent-to-feed ratio of 5, 8~6.5 ,and reflux ratio of 3.0~3.5. Under appropriate operating condition, the yield of ethyl acetate and propyl acetate could reach 95%.