以环己醇为溶剂连续萃取精馏分离丙酮-正己烷

Separation of Acetone and n-hexane by Continuous Extractive Distillation with Cyclohexanol As Solvent

本文应用化工过程模拟软件Aspen Plus V7.3对丙酮—正己烷最低共沸物系的连续萃取精馏过程进行了模拟与优化。通过绘制拟二元汽液平衡相图,筛选出合适的萃取剂为环己醇,确定了双塔连续萃取精馏的工艺流程,并利用灵敏度分析工具考察了萃取精馏塔的全塔理论板数、原料进料位置、萃取剂进料位置、回流比、溶剂比(萃取剂对原料的摩尔比)对分离效果的影响。确定的最佳工艺方案为:全塔理论板数为33,原料和萃取剂分别在第29块和第3块理论板进料,回流比为0.3,溶剂比为3。在此工艺条件下:萃取精馏塔塔顶丙酮的分离效果达99.98%,萃取剂再生塔顶正己烷的纯度达到99.89%。模拟与优化结果为丙酮—正己烷共沸物连续萃取精馏分离过程的设计和操作提供了参考。

Continuous extractive distillation process for acetone-n-hexane azeotropic system is simulated and optimized using Aspen Plus V7.3. By the pseudo-binary phase diagram, cyclohexanol is selected as a suitable extractant.The process of continuous extractive distillation with two columns is confirmed. The separation effect of the number of theory stages, the mixture feed stage, the solvent feed stage, the reflux ratio and the mole ratio of extractant to mixture（solvent ratio） are investigated using sensitivity analysis tool. The optimal condition for the extractive distillation is as follows： the number of theory stages is 33, the mixture feed stage is 29 th, the solvent feed stage is 3rd, the reflux ratio is 0.3, and the solvent ratio is 3. Under the technological condition： The separation effect of acetone of extractive distillation tower of is up to 99.98%. The purity of n-hexane of the extractant-recovery column is 99.89%. The results are useful for the design and operation of continuous extractive distillation process for acetone-n-hexaneazeotropic system