热集成变压精馏分离乙酸乙酯与乙醇工艺及模拟

Simulation for separation of ethyl acetate and ethanol by heat-integrated pressure swing distillation

基于乙酸乙酯与乙醇共沸特性的分析,提出了热集成变压精馏的分离工艺,由加压塔和常压塔串联构成。选择NRTL(non random two liquids)模型为物性计算方法,其二元相互参数由汽液相平衡数据回归,利用AspenPlus软件对提出的分离工艺进行模拟与优化,详细分析了两塔的理论板数、进料位置及回流比对分离的影响,并对比能耗。结果表明,热集成变压精馏分离工艺能很好地实现乙酸乙酯与乙醇的分离,得到最佳的工艺条件,与常规变压精馏相比,热集成变压精馏可节约加热蒸汽34.7%,为共沸物分离的设计和过程节能提供依据。

Heat-integrated pressure swing distillation for separation of ethyl acetate and ethanol was investigated based on the pressure-sensitivity of the azeotropic composition, and the separation sequence was formed by two columns operating at different pressures. The simulation of separation process was carded out satisfactorily by means of a package of com- mercial software Aspen Plus and using the thermodynamic model NRTL （non random two liquids） with binary parame- ters between ethyl acetate and ethanol obtained by experimental data of vapor liquid equilibrium （VLE）. The factors af- fecting the separation efficiency and energy consumption including the number of theoretical plates, feed location and re- flux ratio of two columns were analyzed. The results showed that ethyl acetate and ethanol could be efficiently separated by heat-integrated pressure swing distillation, and the optimal conditions were obtained. The heat-integrated pressure swing distillation could save heating steam by 34. 7% compared with conventional pressure swing distillation, which could provide an effective method for the design and energy-saving of azeotropic system separation.