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Prediction Of Vapor-Liquid Equilibrium By HVOS-PR/MDUNIFAC EOS And Activity Coefficient Model

Posted on:2007-01-30Degree:MasterType:Thesis
Country:ChinaCandidate:C B HuFull Text:PDF
GTID:2121360185475114Subject:Applied Chemistry
Abstract/Summary:PDF Full Text Request
In this paper, the merits-and-flaws and the development status of equation of state model and activity coefficient model in solving the process of phase equilibria are introduced at first. The prediction models of HVOS-PR/MDUNIFAC(model 1) and HOVS-PR/MLUNIFAC(model 2) are produced by using PR Equation of state, MDUNIFAC and MLUNIFAC activity coefficient combined with the mixing rule of HVOS. The vapor-composition , bubble temperature of vapor-liquid equilibria for 93 binary systems(2482 experimental data) and the vapor-composition , bubble pressure of vapor-liquid equilibria for 98 binary systems(3838 experimental data) were predicted, the prediction results of both models were contrasted, it shows that both models are famous in predicting most kind of vapor-liquid equilibria, except some systems contained water polar, but the prediction accuracy of model 1 is, in some degree, better than that of the latter. So, the model 2 was chosen in the following work.The group interaction parameters for 20 group combinations were refitted with Nelder-Mead simplex method by predicting 40 binary vapor-liquid equilibria(2546 experimental data) systems. Additionally, 7 new group interaction parameters were fitted by predicting 7 ternary vapor-liquid equilibria systems (361 experimental data); the model (Nelder-Mead simplex method) was applied to predict the vapor-liquid equilibria for 24 ternary systems(852 experimental data) at different temperature and pressure to test the accuracy of modified and supplemented group interaction parameters. Compared results calculated by using this new parameters and original parameters with the experimental data, it shows new parameters is much better than original parameters at calculating those systems obtained alcohol and acid none-polar.The absolute deviation of vapor-composition is less than 0.05 and the relative deviation of bubble-pressure is less than 6%; the results of prediction for the binary and ternary water-polar systems were improved slightly because of the existing hydrogen-bonding and association effect for polar systems with water.According to the result, new group interaction parameters are right. The original MDUNIFAC group interaction parameters matrix and extend the range of application of this model are extended. The new group interaction parameters in this paper were proved that it have important practical application values in chemistry reaction engineer, separating engineer and chemical process.
Keywords/Search Tags:Group Contribution Method, Vapor-Liquid Equilibrium, Equation Of State, Mixing Rule, Group Interaction Parameters
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