An energy-saving five-column methanol multi-effect distillation process was proposed based on analyzing the deficiency of the existing methanol double-effect distillation process. In the new five-column scheme, one medium-pressure column is added after the existing four higher-pressure columns so that the purified methanol product can be obtained as the overhead products with an appropriate proportion from higher-pressure column, medium-pressure column, atmospheric column and recovery column accordingly in the new scheme. The load of the original higher-pressure and atmospheric column can be decreased by about 30％, while the operating pressure of recovery column can be raised. Thus a multi-effect distillation model with three-group heat integration among higher-pressure and medium-pressure columns, medium-pressure and atmospheric columns, recovery and pre-mn columns was created. The steady-state process simulation results indicate that the temperature differences at two sides of each heat exchanger are appropriate, allowing effective heat transfer. The result shows that the energy consumption of the five-column scheme can be reduced by 28.6％, compared with the four-column scheme. Significant savings in operating costs can therefore be achieved, resulting in an economically viable process for methanol distillation.%在分析现有甲醇双效精馏工艺存在不足的基础上,提出了一种节能的五塔甲醇多效精馏新工艺.五塔新工艺在现有四塔工艺的加压塔之后增加了1台中压塔,精甲醇按适当比例分别由加压塔、中压塔、常压塔和回收塔塔顶采出,使原加压塔和常压塔负荷减少约30%;同时适当提高了新回收塔的操作压力,使加压塔与中压塔、中压塔与常压塔、回收塔与预塔形成3组热集成的双效精馏模式.对新旧2种工艺进行稳态模拟计算和技术经济比较,结果表明:五塔新工艺各换热器二侧均有适宜的传热温差,节能达28.6%,经济效益显著.
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