混合溶剂间歇萃取精馏分离过程的模拟

由于混合溶剂存在"混合溶剂效应",能够解决简单溶剂选择性与互溶性相互矛盾的问题,因此混合溶剂间歇萃取精馏技术可以大大拓宽传统单一溶剂间歇萃取精馏分离技术的应用空间。文章建立了反映常规混合溶剂间歇萃取精馏过程的恒摩尔持液数学模型,并运用2点隐含法对其求解,结果表明,模拟计算结果与实验结果吻合较好。随后运用该模型探讨了塔身持液量、混合溶剂进料位置等因素对混合溶剂常规间歇萃取精馏的影响。得出以下结论,产品馏出速率随塔身持液量的增大而减小,塔顶馏分产量与塔身持液量的关系不大。另外,混合溶剂进料位置的选定对分离效果也有较大的影响,需要正确选择。

Simulation on process of batch extractive distillation with mixed solvent

Development of traditional batch extractive distillation with single solvent is limited because the selectivity of single solvent usually conflicts with its solubility.A regular batch extractive distillation with mixed solvents can extend greatly batch extractive distillation technology because of "Effect of Mixed Solvents".The process of a regular batch extractive distillation with mixed solvents was simulated by a constant molar holdup model,which was solved by two-point implicit method.In the same condition as simulation,cyclohexane-benzene azeotropic mixture was separated using N,N-dimethyl formamide(DMF) and dimethyl sulfoxide(DMSO) as binary mixed solvent.Experiment results agree well with simulation.And the effect of column holdup and feed location of mixed solvent on the separation process was investigated.The productive rate decreases with the increase of column holdup,and the amount of product has almost not an obvious change.In addition,feed location of mixed solvent has an important influence on separation of azeotropic mixture,which must be chosen correctly.