复合溶剂间歇萃取精馏乙醇-水的研究

采用N,N-二甲基甲酰胺和二甲基亚砜及其组成的复合溶剂为萃取剂,在间歇萃取精馏实验装置上研究了乙醇-水共沸体系的分离过程。实验考察了溶剂种类、溶剂流率、回流比等因素对分离效果的影响。实验结果表明:复合溶剂的最佳配比为7∶3(二甲基亚砜与N,N-二甲基甲酰胺质量比);随着溶剂流率与回流比的增大,复合溶剂分离效果增强;在最佳配比下,当回流比为2,溶剂流率为15 mL/min时,乙醇的质量分数可达99.14%,比单一溶剂N,N-二甲基甲酰胺和二甲基亚砜分别提高了3.29%和1.71%,且单位产品溶剂消耗最低为1.58 mL/mL,此时复合溶剂间歇萃取精馏乙醇-水的综合效果最好。

Study on mixed solvent for separating ethanol and water by using batch extractive distillation

A batch extractive distillation process for separating ethanol and water system was studied by employing N,N-dimethylformamide(DMF),dimethyl sulfoxide(DMSO) and the mixture of them as solvents.The effects of different types of solvent,solvent rate,and reflux ratio on separation process were investigated.The results show that the most suitable mass ratio of DMSO to DMF in the mixed solvent is 7 ∶ 3;the separation effect is improved with the increasing of solvent rate and reflux ratio;under the conditions that the optimum value of solvent m(DMSO) ∶ m(DMF)=7 ∶ 3,reflux ratio is 2,and flow rate of solvent is 15 mL/min,the mass fraction of ethanol reaches 99.14%,which is improved by 3.29% and 1.71% than DMF and DMSO respectively;and the lowest unit consumption of solvent is 1.58 mL/mL.