Abstract: Two energy-saving processes of methanol distillation were proposed. In the improved three-column process with double-effect distillation, the vapor from higher-pressure column was not only the heat source of the lower-pressure column, but also the heat source of pretreatment column. A new higher-pressure column was added in the four-column process with double-effect distillation, and its vapor was used to heat up the reboiler of pretreatment column. The distillate of the new higher-pressure column is methanol product and the bottom stream is waste water. A steady-state simulation was carried out. The result showed that the difference of temperature at two sides of heat exchangers was appropriate so the heat exchangers could work normally. A comparison between two energy-saving processes and the traditional three-column processes indicated that the improved three-column process reduced the heat consumption by 16.67% of traditional three-column process and the four-column process reduced the heat consumption by 16.17% of traditional three-column process.

摘要： 提出两种节能型甲醇精馏新工艺。在改进的三塔双效精馏工艺中，加压塔的蒸汽不仅用作常压塔的热源，还同时供给预塔的再沸器。四塔双效精馏工艺在传统三塔流程中新增一个加压塔，它的蒸汽用于预塔的再沸器，新增加压塔的塔顶得到精甲醇产品，塔底排出废水。对两种新工艺进行了稳态模拟，结果表明各换热器的两侧有合适的温差，换热器可以正常工作，对3种工艺的对比表明，改进的三塔工艺比传统三塔工艺节能16.67%，四塔工艺比传统三塔工艺节能16.17%。