分壁式萃取精馏塔制取高纯度甲缩醛的模拟与优化

Simulation and optimization of the methylal purification by extractive dividing wall column

建立一种利用分壁式萃取精馏塔制取高纯度甲缩醛的新工艺,并用AspenPlus软件对该工艺进行模拟和优化。最优工艺参数为:主塔塔板数39,隔板底端位置在第3l块板,原料进料在第17块板,萃取剂进料在第4块扳,回流比为0.9,溶剂比为1.0,气相分配比为0.12。最优参数下的严格模拟结果显示:本工艺可得到质量分数99.96%的甲缩醛和99.24%的甲醇;与常规萃取精馏工艺相比,再沸器和冷凝器热负荷分别降低14.8%和16.9%。说明分壁式萃取精馏塔制取高纯度甲缩醛不仅技术上可行,而且能减少一个塔的投资和节约分离过程的能耗,在经济上也具有显著的优势。

A novel process of methylal purification by extractive dividing wall column was developed. Simulation and optimization were carded out by Aspen Plus software. The optimized parameters were as fellow： plate number was 39, bottom of dividing wall was placed on 31 stage, feed stage was 17, extractant feed stage was 4, reflux ratio was 0.9, ratio of solvent was 1.0 and vapor split ratio was 0.12. Rigorous simulation results in the optimized parameters showed that 99.96 % methylal and 99.24 % methanol in mass fraction could be obtained by this process. Compared with conventional extractive distillation process, reboiler load saving of extractive dividing wall column was 14.8 % and condenser load saving was 16.9 %. This showed that the methylal purification by extractive dividing wall column is not only feasible in technology, but also has significant economic advantage because of lower capital costs and saving energy.