Methanol-Acetonitrile Separation By Extractive Distillation Using ILs

Abstract

Present paper includes the usage of Ionic Liquids as greener solvents in extractive distillation by substituting conventional solvents. For the separation of minimum boiling methanol-acetonitrile azeotropic system, extractive distillation was carried out in Aspen HYSYS process simulator by using ionic liquids as solvent. Three imidazolium based ionic liquids namely 1-butyl-3-methylimidazolim acetate ([BMIM][OAc]), 1-butyl-3-methylimidazolium chloride ([BMIM][Cl]), 1-butyl-3-methylimidazolium bromide ([BMIM][Br]) used, were added as hypothetical compound in Aspen HYSYS. Flowsheet was simulated using NRTL as the thermodynamic model, giving a purity of 99.9% by mol of methanol in distillate. Optimization of distillation process was done by varying flow rate of ionic liquid, column stages, feed stage location, ionic liquid stage location and reflux ratio. A Total Cost Analysis (TAC) was carried out by using Economic Analyzer in Aspen HYSYS to compare the optimized design. [BMIM][OAc] is found to most suitable according to the energy and cost analysis.