完全热集成变压精馏分离环己烷和乙酸乙酯的模拟

SIMULATION OF SEPARATION OF CYCLOHEXANE AND ETHYL ACETATE BY FULLY HEAT-INTEGRATED PRESSURE SWING DISTILLATION

由于环己烷-乙酸乙酯为压力敏感体系,可用变压精馏工艺对环己烷和乙酸乙酯共沸物进行分离。利用化工流程模拟软件对分离过程进行模拟优化,以NRTL活度系数方程作为物性计算方法,高压塔和常压塔再沸器总热负荷最低为目标,对理论板数、进料位置和回流比参数进行优化。通过模拟计算得到纯度不低于99.5%的环己烷和乙酸乙酯产品。在变压精馏的基础上对系统进行热量集成,与常规变压精馏相比,完全热集成变压精馏冷凝器可节能34.97%,再沸器可节能33.91%;完全热集成变压精馏可得到质量分数分别为99.97%和99.78%的环己烷和乙酸乙酯产品。

Pressure swing distillation process was proposed for separation of the cyclohexane and ethyl acetate azeotropic mixture because of its pressure sensitivity. The separation process was simulated and optimized by the chemical process simulation software. The NRTL model was used as the physical property calculation method. With the lowest of the total heat load of the high pressure tower reboiler and the atmospheric tower reboiler as the target, the number of theoretical plates, the feeding location and the mass reflux ratio parameters were optimized. The product of cyclohexane and ethyl acetate with purity of not less than 99. 5% was obtained by simulation. On the basis of the pressure swing distillation , the fully heat-integrated pressure swing distillation process was proposed. Compared with the conventional pressure swing distillation, the fully heat-integrated pressure swing distillation con-denser could save 34. 97% of energy, the reboiler could save 33. 91%, and the cyclohexane and ethyl acetate with the mass fraction of 99. 97% and 99. 78% could be obtained.