Vapor-liquid Equilibrium And Extractive Distillation Simulation Of N-hexane And 1,2-dichloroethane System

In the industrial production of battery electrolyte additive process,industrial waste containg n-hexane and 1,2-dichloroethane are produced.The recycling and utilization of industrial waste liquor are of great significance for environmental protection.The lowest homogeneous azeotrope of n-hexane and 1,2-dichloroethane is formed under atmosphere pressure at normal temperature,the vapor-liquid equilibrium and extractive distillation process of the azeotropic system were studied.The extractants used in the extractive distillation process are important.With preliminary screening,three extractants,tert-butyl acetate,sec-butyl acetate and n-propyl acetate,are selected for further validation.Seven binary vapor-liquid equilibrium data: n-hexane(1)+ 1,2-dichloroethane(2)system,n-hexane(1)+tert-butyl acetate(2)system,n-hexane(1)+ sec-butyl acetate(2)system,n-hexane(1)+npropyl acetate(2)system,1,2-dichloroethane(1)+tert-butyl acetate(2)system,1,2-dichloroethane(1)+ sec-butyl acetate(2)system,1,2-dichloroethane(1)+n-propyl acetate(2)system were carried out at 101.3 k Pa.All the experinment data passed the thermodynamic consistency check.Using NRTL,UNIQUAC and Wilson activity coefficient models to correlate the seven binary systems,and the binary interaction parameters were obtained.The predicted results of the three models agreed well with the VLE data.In order to find out the best fitted model for different systems,RMSD and ADD were caculated.UNIQUAC is the best fitted model for nhexane(1)+ 1,2-dichloroethane(2)system,n-hexane(1)+ tert-butyl acetate(2)system,1,2-dichloroethane(1)+ sec-butyl acetate(2)system,1,2-dichloroethane(1)+ n-propyl acetate(2)system and 1,2-dichloroethane(1)+ sec-butyl acetate(2)system.Wilson is the best fitted model for n-hexane(1)+ sec-butyl acetate(2)system and n-hexane(1)+ n-propyl acetate(2)system.Using the correlated binary interaction parameters to predict ternary VLE data,the y-x diagrams of n-hexane(1)+ 1,2-dichloroethane(2)system with different solvens and RCM curves were plotted.The results show that all the solvents can break the azeotrope.The extractive distillation process with three solvents were carried out using Aspen Plus,and sensitivity analysis were carried out.Comparing the heat duty of three process,the result shows that sec-butyl acetate is the best solvent.Based on vapor-liquid equilibrium experiment and simulation study of extractive distillation process,the separation of azeotropic system was realized,the suitable solvent was selected and the vapor-liquid equilibrium database was expanded.The paper provided data support for futher study,and had certain significance for industrial recovery of waste solvents.