丙酮-甲醇共沸体系分离及工业流程优化

Separation and industrial process optimization of acetone-methanol azeotrope system

为了有效地分离丙酮-甲醇共沸混合物实现工业化应用,在101.3 kPa下测定了[BMMIM][Ac](1-丁基-2,3-二甲基咪唑醋酸盐)作为萃取剂的三元气液相平衡数据。实验结果表明:离子液体的加入会使体系产生显著的盐析效应。丙酮-甲醇物系的相对挥发度随着体系中离子液体摩尔分数的增大而增大。当离子液体摩尔分数达到一定时共沸现象消失。分析实验数据并关联NRTL模型,得到二元交互作用参数和最小打破共沸所需离子液体摩尔分数为0.019 7,利用Gaussian 09软件在分子水平上计算出两两分子间相互作用能来探究分离机理。采用Aspen Plus软件对丙酮-甲醇体系进行了萃取精馏过程模拟,在保证塔顶产品丙酮和甲醇产率摩尔分数均为99.99%的条件下优化最佳工艺参数。表明以[BMMIM][Ac]为萃取剂萃取精馏丙酮-甲醇共沸物具有良好效果。

In order to effectively separate acetone-methanol azeotropic mixtures and realize industrial applications,the ternary vapor-liquid equilibrium data of[BMMIM][Ac](1-butyl-2,3-dimethylimidazolium acetate)as extractant were determined at 101.3 kPa.The experimental results show that the addition of ionic liquids will cause a significant salting-out effect in the system.The relative volatility of the acetone-methanol system increases with the increase of the molar fraction of the ionic liquids(ILs)in the system.When the ionic liquids molar fraction reaches a certain level,the azeotropic phenomenon disappears.The experimental data were analyzed and the NRTL model was correlated to obtain binary interaction parameters.The molar fraction of ionic liquids required to break the azeotropic minimum is 0.0197.By using Gaussian 09 software,the pair-to-pair-to-molecule interaction energy was calculated at the molecular level to explore the separation mechanism.The extraction distillation process of the acetone-methanol system was simulated by Aspen Plus software,and the optimal process parameters were optimized under the condition that the molar fractions of acetone and methanol yield of the top of the tower were 99.99%.The results show that the extraction of acetone-methanol azeotrope using[BMMIM][Ac]as the extractant has a good effect.