萃取精馏分离甲醇-乙腈的研究  

Separation of methanol-acetonitrile by extractive distillation

作　　者：于洋[1] 白鹏[1] 庄琼红[1] 

机构地区：[1]天津大学化工学院,天津300072

出　　处：《化学工程》2011年第6期36-39,共4页Chemical Engineering(China)

摘　　要：为了分离甲醇-乙腈共沸混合物,研究了萃取精馏在甲醇-乙腈共沸物系中的应用。通过溶剂极性比较初选出萃取精馏溶剂,由ChemCAD软件模拟和气液平衡实验验证选定出合适的溶剂用于萃取精馏分离甲醇-乙腈共沸混合物,通过萃取精馏实验考察了所选萃取精馏溶剂的效果。结果表明:N,N-二甲基甲酰胺(DMF)能够消除甲醇-乙腈共沸物系的共沸。采用Wilson模型对常压下甲醇-乙腈物系和加入溶剂N,N-二甲基甲酰胺的汽液平衡进行模拟,模拟数据与实验结果吻合较好。采用有33块理论板,其中净化回收段填料层3块理论板,萃取精馏段填料层30块理论板的填料塔进行间歇萃取精馏实验分离甲醇-乙腈共沸混合物,回流比为4,溶剂质量比为3∶1时在塔顶得到产品甲醇质量分数为95.76%。说明N,N-二甲基甲酰胺作为溶剂的萃取精馏分离甲醇-乙腈共沸混合物是可行的。In order to separate methanol-acetonitrile azeotropic mixture,the application of extractive distillation to separation of methanol-acetonitrile was researched.By comparing solvent polarity,the simulation by ChemCAD software and VLE experiment were used to select the suitable solvent for the separation of methanol-acetonitrile azeotropic mixture by extractive distillation.The effectiveness of the solvent selected was investigated by the extractive distillation experiments.The results show that N,N-dimethylformamide（DMF） as solvent can break the azeotrope of methanol-acetonitrile system.Wilson model was used in the simulation of the VLE of methanol-acetonitrile system as well as when DMF was added under atmospheric pressure.The simulation data agree well with the experimental results.The experiment of separation of azeotropic mixture of methanol and acetonitrile by batch extractive distillation was carried out in a packed column of 33 theoretical plates.The purification and recovery section has 3 theoretical plates and the extractive distillation section has 30 theoretical plates.With the reflux ratio of 4 and the solvent mass ratio of 3 ∶ 1,the product mass fraction of methanol reaches 95.76%.It reveals that the extractive distillation with N,N-dimethylformamide as solvent is useful in the separation of methanol-acetonitrile.

关 键 词：萃取精馏 N N-二甲基甲酰胺 甲醇 乙腈 

分 类 号：TQ028.13[化学工程]