以苯-甲苯-二甲苯精馏的MESH方程组为基础，用proⅡ模拟软件模拟，考察苯-甲苯-二甲苯物系组成对节能率的影响，并找出产品纯度对连接流股流量变化的灵敏度，在L/V'为1.5时，塔顶、塔中、塔釜产品均达到最佳条件，在保证L/V'最优前提下，以年费用即操作费用与设备折旧费用之和最小为目标函数，调节回流比及理论板数，优化苯-甲苯-二甲苯分离工艺，得出最优设计方案。结果表明，经优化设计的苯-甲苯-二甲苯物系的热偶精馏工艺比最好的普通精馏工艺节约能耗近40%。

Based on MESH equation set of benzene-toluene-xylene distillation,stimulation is carried out by proⅡ software to evaluate the effects of benzene-toluene-xylene composition on the energy efficiency and to find out the sensitivity of product purity to the changes of flow rate of cycle streams.When the value of L/V' is 1.5,purities of products at column top,mid-column and column bottom are all at their best.The optimal design scheme is obtained through adjusting reflux ratio and theoretical plate number,and optimizing the separation process of benzene-toluene-xylene by aiming at minimum of annual operation cost and equipment depreciation in the premise of optimal L/V'.The results show that energy consumption of the optimized thermally coupled distillation process for benzene-toluene-xylene system is nearly 40% of that of common distillation process.

李瑞端(1983-),女,博士,讲师