Ethanol-Dimethyl Carbonate-Furfural Vapor-Liquid Equilibrium And Study Of Extractive Distillation Simulation And Experiment

In the production of carbonate electrolytes,the separation of Et OH-DMC azeotrope is involved,which brings some difficulties for the purification.In order to realize the industrial application of Et OH-DMC azeotrope separation,vapor-liquid equilibrium experiments,process simulation and optimization,and intermittent extractive distillation experiments have been completed in this paper.Specific work is as follows:(1)The UNIFAC group contribution method was used to quantitatively analyze and predict the separation effect of five organic entrainers on Et OHDMC,and the relative volatility improvement effect was obtained as follows:furfural > chlorobenzene > p-xylene > cyclohexanone > butyl butyrate.Finally,furfural was selected as an entrainer for separating the Et OH-DMC azeotrope system.(2)The ternary VLE data of Et OH-DMC-furfural were measured with the Otherm phase equilibrium kettle(furfural molar purity is 0.10,0.20,and 0.30).The VLE data were regressed with NRTL,WILSON,and UNIQUAC models,and the model parameters were obtained.The deviations were represented by ARD,which are 3.09%,3.86%,and 3.35%,respectively.Comparing the calculated deviations of the three models,the NRTL model has the best data regression effect.(3)The Et OH-DMC separation process was simulated by extractive distillation with Aspen Plus,and the process parameters were optimized by the sequential module method with minimum TAC as the optimization objective.According to the thermal integration process,compared with the conventional scheme,the energy lost in the process was reduced by 19.5%,the CO2 emission rate was reduced by 45.8%,the total energy consumption was reduced by 52.9%,and the TAC was saved by 17.4%.(4)Using furfural as an entrainer,the extraction distillation experiment of Et OH-DMC was completed to study the changes in ethanol purity at the top of the column under different reflux ratios and entrainer flow rates.When the entrainer flow rate was 40 m L/min and reflux ratio R=2,the top of the column obtained ethanol with a mass purity of 98.8%.The intermittent extractive distillation experimental simulation is finished,and the experimental and simulation results match up.In summary,in order to separate the Et OH-DMC binary azeotrope,this paper studied the vapor-liquid equilibrium relationship of Et OH-DMC and furfural,simulated and optimized the separation process of Et OH-DMC by continuous extractive distillation,and finally completed the intermittent extractive distillation experiment to verify the separation effect after adding entrainer.It provides a theoretical reference and an experimental basis for separating Et OH-DMC by extractive distillation.