环己烷-乙酸乙酯萃取精馏分离的研究

Separation of cyclohexane and ethyl acetate by extractive distillation

通过UNIFAC基团贡献法和氢键间相互作用,初步筛选二甲基亚砜(DMSO)作为萃取剂,通过萃取精馏分离环己烷与乙酸乙酯物系。在常压下模型模拟加入二甲基亚砜后环己烷与乙酸乙酯体系的汽液相组成,NRTL模拟结果与汽液平衡实验所得数据相似度高,结果表明二甲基亚砜作为萃取剂可以有效打破该共沸体系。同时进行间歇萃取精馏实验,填料理论塔板数为33,回流比1.0,溶剂比为1.0时可以得到质量分数为98.7%的环己烷,回收率为87.8%。最后在Aspen Plus软件帮助下研究二甲基亚砜连续萃取精馏分离环己烷-乙酸乙酯物系的工艺,萃取精馏塔塔顶环己烷的质量分数可达99.6%,溶剂回收塔塔顶乙酸乙酯的质量分数为99.5%,塔底回收二甲基亚砜套用,为进一步的工业应用提供参考。

Dimethyl sulfoxide （DMSO） was chosen as the solvent for separation of cyclohexane-ethyl acetate system in extractive distillation by the UNIFAC group contribution algorithm andhydrogen bonding interactions. The simulation of vapor-liquid equilibrium for cyclohexane-ethylacetate system with dimethyl sulfoxide under atmospheric pressure was performed. Thesimulation results using NRTL mode agreed well with the vapor-liquid experimental data. Itindicated dimethyl sulfoxide can effectively break the azeotrope system. With the solvent massratio of 1.0 and the reflux ratio of 1.0, the mass fraction of cyclohexane reaches 98. 7% in apacked column of 33 theoretical plates, and the recovery was about 87.8%. Finally, Aspen Pluswas used to simulate the separation of eyelohexane-ethyl acetate system in continuous extractivedistillation process. The cyclohexane was obtained with mass fraction of 99.6% at the top of theextractive distillation column and the mass fraction of ethyl acetate was 99.5~//00 in solventrecovery tower. Dimethyl sulfoxide was recycled at the bottom of the tower. The study canprovide reference for further industrial application.