Research On The Extraction Distillation Of Water And 1-Propanol System With Ionic Liquid

1-propanol is an important chemical material and solvent, and it has extensive applications. Ionic liquids(ILs) have many advantages such as low vapor pressure, non-volatilization, wide rang temperature and steady chemical properties while compared with the traditional organic solvents. The feasibility of using [HMIM][C1] ionic liquid as solvent for the separation of the azeotropic mixtures of water and 1-propanol by extractive distillation is researched in this study.Vapor-liquid equilibrium data for water-1-propanol system containing [HMIM][C1] ionic liquid were measured in a novel ebulliometer at 101.3kPa and at several constant IL mass fractions. The vapor-liquid equilibrium data obtained were correlated by NRTL model. The results show this kind of IL rise the relative volatility of 1-propanol to water prominently. The relativity of 1-propanol to water increase with more addition of IL. When keeping constant mass fraction of IL, the relativity of 1-propanol to water decrease as the mole fraction of 1-propanol increase. When the mass fraction of the [HMIM][C1] is about 0.5, it can lead to eliminate the azeotropic point of water -1-propanol system.Extractive distillation for preparation of anhydrous 1-propanol was simulated by Aspen Plus simulation software at 101.3 kPa, mass fraction of 1-propanol solution 70% and [HMIM][C1] as extractant. Effects of feed and extractant input positions, extractant ratio and reflux ratio on the top 1-propanol mass fraction were investigated. 1-Propanol content at tower top increases when extractant ratio and reflux ratio lifts up. The lower the extractant input position or the higher the feed input position, the lower purity of 1-propanol at tower top will be. When the number of stage is 32, the feed stage is number 15, the extractant stage is number 2, the reflux ratio is 2, and the extractant ratio is 2, the mass fraction of 1-propanol at tower top can reach 99.71%.