Vapor-liquid Equilibrium Experiment Of Methanol-ethyl Formate-entrainer And The Simulation Of Extractive Distillation

Methanol and ethyl formate are important and basic chemical raw materials,their mixture could generate azeotrope under normal pressure and temperature.In order to separate them completely and obtain high purity products,special distillation should be used.In this paper,three entrainers were selected for extractive distillation for methanol-ethyl formate azeotropic system,including ionic liquids([MMIM][DMP],[EMIM][OAC])and organic solvent(DMSO).(1)The VLE data of methanol-ethyl formate binary system at atmospheric pressure(101.3 kPa)was determined by improved Othmer and thermodynamic consistency was verified.And VLE data of ternary systems:methanol-ethyl formate-DMSO,methanol-ethyl formate-[MMIM][DMP]and methanol-ethyl formate-[EMIM][OAC]was measured,too.(2)The effect on VLE produced by type and concentration of entrainers was analyzed.The experimental result showed that DMSO,[MMIM][DMP]and[EMIM][OAC]all destroyed the azeotropic state of methanol-ethyl formate effectively and improved the relative volatility of system.The higher entrainer was added,the greater relative volatility's increasement was,and the influence on vapor-liquid equilibrium of system also was more obvious.For the separation effect,it showed[EMIM][OAC]>[MMIM][DMP]>DMSO.(3)Wilson model,NRTL model and UNIQUAC model were used to fit the VLE data of methanol-ethyl formate,methanol-ethyl formate-entrainer.Binary interaction parameters were got and the suitability and veracity of thermodynamic models was studied.By analysis,three models all had good fitting effect and applicability for binary and ternary systems,and their deviation all were less than 5%.Among them,the deviation of NRTL model was the least.(4)Process simulation was carried out by Aspen Plus software and DMSO and[EMIM][OAC]were used as entrainer.NRTL model was used for the simulation.The simulation verified its feasibility of experimental scheme and the process was optimized with the objective function(TAC)to determine the best operating conditions.Compared the results of two simulations,it was found that the amount of[EMIM][OAC],TAC and energy consumption all were smaller for extractive distillation process used[EMIM][OAC].In conclusion,extractive distillation was applied for methanol-ethyl formate azeotrope that used DMSO,[MMIM][DMP]and[EMIM][OAC]as entrainer,and the VLE data for system was measured.Besides,activity coefficient models were used for data fitting,the binary interaction parameters and suitability of models would be got.And the simulation was finished and optimized,accuracy of experimental scheme also was verified.