热集成变压精馏分离甲苯-异丙醇的模拟

Simulation of heat-integrated pressure swing distillation for separation of toluene-isopropyl alcohol

甲苯-异丙醇混合物的共沸组成对压力较为敏感,为此提出了热集成变压精馏工艺分离该共沸物。利用ASPENPLUS化工模拟软件,以修正的WILSON活度系数方程作为物性计算模型,以甲苯和异丙醇的纯度作为约束变量,以分离过程能耗最低为目标函数,对主要工艺参数进行了模拟优化,得到了热集成变压精馏分离甲苯-异丙醇体系的最佳工艺操作参数及设备参数。模拟结果表明,采用带热集成的变压精馏工艺,即用常压塔的塔顶潜热作为负压塔的塔釜热源,用常压塔的塔底显热对原料预热器供热,与两塔均采用外界蒸汽供热的传统变压精馏方式相比,可以节约能耗约30.7%。研究结果为甲苯-异丙醇混合物和类似的共沸体系的分离提供了一条新的节能技术路线。

A heat-integrated pressure swing distillation（PSD） process for separating a homogeneous azeotropic mixture composed of toluene and isopropyl ethanol was proposed due to its sensitive character to the system pressure.By minimizing the energy consumption when the purities of toluene and isopropyl ethanol were fixed,the optimum simulation was performed by means of a package of commercial software ASPEN PLUS and a corrected thermodynamic model WILSON equation,and the optimum operating conditions and equipment parameters were determined.The simulation results show that the PSD process heat-integrated by condensing the normal-pressure column distillate against the evaporation of the mixture in the negative-pressure column reboiler can save energy by 30.7% compared with the conventional PSD process,thus supplying an effective and new kind of separation scheme for toluene-isopropyl ethanol and similar azeotropic mixtures.