甲醇气相脱水制二甲醚多段原料气冷激反应器模拟与优化

摘要

Upon the demand of megaton DME (dimethyl ether) production, a kinetics of gas dehydration of methanol to dimethyl ether was developed and a fixed bed reactor model with multi-segment feed quenches was established. The model could predict the concentration and temperature distribution along the axial direction in the bed. Through the reactor simulation and model sensitivity analysis, a set of process parameters was optimized. The optimal operating condition requires three stage feed-quenches with methanol allocation of 7:2:1; the outlet temperature at each stage is almost the same with the maximum outlet temperature of 360℃. The result shows that a lower quench-gas temperature does not always result in a better reactor performance. When the inlet and quench temperature are 260.0 ℃ and 140.0℃ respectively, methanol conversion and dimethyl ether yield reach the maximum values.c%针对百万吨级二甲醚生产的要求,建立了甲醇气相脱水制二甲醚的反应动力学模型以及多段原料气冷激的固定床反应器模型,并模拟计算得到甲醇制二甲醚过程中反应器浓度与温度的轴向分布.通过改变操作条件对反应器的参数敏感性进行分析,结果发现,甲醇原料气分为三段进入反应器较为合适,入口气量分配比例最好为7∶2∶1,此时反应器最高出口温度略高于360℃,各段出口温度大致相当,分布较合理；冷激气温度并非越低越有利,当二段入口温度低于催化剂起活温度就没有意义了,在入口甲醇原料温度为260℃、冷激气温度为140.0℃时,甲醇总转化率利二甲醚产量达到最大值.