Study On The Vapor-liquid Equilibrium Of Ethylene Glycol Systems Under Vacuum

Ethylene glycol is one kind of important intermediates, which was widely usedin organic chemical industry.There are many by-products in the production process ofcoal based ethylene glycol, such as1,4-butanediol, diethylene glycol and1,6-hexanediol etc, in order to improve the production efficiency, needs to beseparated.Gas-liquid equilibrium data are the important basic data, separation andpurification in the process design, production operations are needed.There was norelated report of the vapor-liquid equilibrium data between these by-products, so ithad significant value to determine the vapor-liquid equilibrium data of them.In this paper, the main research results are as follows:(1)Four groups binary system and one ternary system gas-liquid equilibriumdata(ethylene glycol-1,4-butanediol,1,4-butanediol-diethylene glycol,1,4-butanediol-1,6-hexanediol、 diethylene glycol-1,6-hexanediol and1,4-butanediol-diethyleneglycol-1,6-hexanediol) was measured, and draw out the four groups of binary systemy-x and T-y-x phase diagram.Area inspection method was used to examine thethermodynamic consistency of the experimental data of four groups of binarysystem, the results showed that all data passed the thermodynamic consistency test.(2)The experimental data of the four binary systems were correlated by thewidely used three activity coefficient models NRTL, WILSON and UNIQUAC inAspen Plus. The optimal binary interaction parameters were obtained for each binarysystem of different models.And experimental value of the binary system arecompared with those of the simulation values, the results show that the three modelsare good for four groups of binary system to simulate the gas-liquid balance.(3)Aspen plus was used to predict the vapor-liquid equilibrium data of twoternary system (ethylene glycol-1,4-butanediol-diethylene glycol,1,4-butanediol-diethylene glycol-1,6-hexanediol). And the simulated values and experimental valuesof1,4-butanediol-diethylene glycol-1,6-hexanediol were compared, the results showthat the three model equations are applicable.