耦合法在回收甲醇和二氯甲烷中的研究及应用

Research and application of coupling method on recycling methanol and dichloromethane

甲醇和二氯甲烷是农药及医药中间体生产过程中常用的优良溶剂,两者会形成共沸物,为了实现两者的完全分离,文中提出了一种精馏-萃取耦合的工艺解决方案。通过萃取实验研究了不同萃取剂对甲醇、二氯甲烷混合物的分离效果;考察了以水作为萃取剂时萃取比、萃取温度及萃取填料高度对分离结果的影响,拟合了可用于工艺包设计的关联方程,通过成本运算获得了最佳的萃取条件;结合萃取实验结果及以往工程经验,通过Aspen Plus软件对工艺方案进行了模拟优化,获得了理论板数、进料位置及回流比的最优数据。该工艺解决方案已在企业中得到应用和检验。

Methanol and dichloromethane are excellent solvents commonly used in the production of pesticides and pharmaceutical intermediates,and both will form an azeotrope.In order to separate them completely,a distillation-extraction coupling process solution was proposed in the paper.The effect of different extractants on methanol and dichloromethane separation efficiency was studied by extraction experiments.The effect of extraction ratio,extraction temperature and filler height on the separation results with water as extractant was investigated,the correlative equation which can be used in process design was fitted,and the optimum extraction conditions were obtained by cost calculation.Based on the experimental results of extraction and previous engineering experience,the process scheme was simulated and optimized by Aspen Plus software,and the optimal data of theoretical plate number,feed position and reflux ratio were obtained.The process solution was applied and tested in enterprises.