The Effects Reaserch Of Ionic Liquids On Two Azeotropic Systems And Simulation Of Extractive Distillation For Optimization

In recent years, the study of using ionic liquids as the extractant of extractive distillation has become a hot topic due to their special properties. It provides a new way of separating the methanol-acetonitrile> methanol dimethyl carbonate ?DMC? and some other azeotrope. The vapor-liquid equilibrium ?VLE? data of two azeotropic systems of methanol-acetonitrile and methanol-DMC have been measured at 101.3 kPa. Three kinds of bis ?trifluoromethylsulfonyl? imide based ionic liquids ?[EMIM][NTf₂], [BMIM][NTf₂], [HMIM][NTf₂]? were used as the extractant to separate those two systems. Besides, three kinds of models ?Wilson, NRTL, eNRTL? were adopted to correlate VLE experimental data. TQ-501 column has been simulated and optimized using simulation software Aspen Plus. Specific work:1. VLE study of methanol-acetonitrile system. The VLE data of methanol-acetonitrile binary system and three ternary systems with [EMIM][NTf₂], [BMIM][NTf₂], [HMIM][NTf₂] were measured at 101.3 kPa. The mole fraction of ILs were 0.05,0.10 and 0.15 respectively. The results indicated that all these three ILs had an obvious salting-out effect on the methanol-acetonitrile system that increased the relative volatility of methanol to acetonitrile and dropped the activity coefficient of acetonitrile. The ILs also raised the equilibrium temperature of methanol-acetonitrile system. All the ILs could eliminate the azeotropic point when the mole fraction of them were 0.05. The extraction effect follows the order:[EMIM][NTf₂]> [BMIM][NTf₂] >[HMIM][NTf₂].2. VLE study of methanol-DMC system. The VLE data of methanol DMC binary system and two ternary systems with [EMIM][NTf₂], [BMIM][NTf₂] were measured at 101.3 kPa. The results indicated that those two ILs had an obvious salting-in and salting-out effect on the methanol DMC system that raised the equilibrium temperature of methanol-DMC system. All the ILs could eliminate the azeotropic point when the mole fraction of them were 0.05. The extraction effect follows the order: [BMIM] [NTf₂]> [EMIM] [NTf₂].3.Regression of activity coeffeicient models. The Wilson, NRTL and e-NRTL models were used to correlated the VLE data of methanol acetonitrile and methanol-DMC respectively. The devictions showed that these three models could well reproduce all the binary systems and NRTL and e-NRTL were better. But for ternary systems, the NRTL model had the best result of correlation, Wilson and e-NRTL models gave less satisfied results.4. Simulation and optimization of TQ-501 in the production of polyving akohol. Comparing the data of Aspen Plus with literature, the NRTL model was selected to calculate the properties of MeOH-MeOAc-H2O. Then this study used NRTL model to correlate the literature data and got the binary interaction parameters. The operating parameters of TQ-501 distillation column were simulated and optimized. The best values were determined:N is 30, R is 1.61, NF is 8, DIF is 0.3345. The sensitive plate location were determined as 14^th plate.