Recent procedures developed by Heidemann (1990) and by Michelsen (1990a, b) enable us to formally incorporate excess Gibbs energy model parameters into a fully consistent equation of state, cith accurate reproduction of the behavior of the excess Gibbs energy model at atmospheric pressure.

This paper investigates the ability of the mixing rules proposed by Michelsen to predict high-pressure phase equilibrium, when used in combination with the parameter table of modified UNIFAC. Considering that a group contribution method is used for the excess Gibbs energy and that model parameters are extrapolated over a 200 K temperature interval, quite satisfactory results are obtained for the mixtures investigated.

In this work, the equation of state-excess Gibbs energy (EoS-G E ) model has been employed to predict Liquid-Liquid Equilibria (LLE) of some binary mixtures at 0.1 MPa. Three binary systems containing Decane+Methanol, Cyclohexane+Methanol and Cyclohexane+2,2,2-Trifluoroethanol (TFE) have been tested using Peng–Robinson EoS modified by Stryjek and Vera (PRSV), along with the excess Gibbs mixing rules MHV1 and MHV2 and two excess Gibbs models: Wilson equation modified by Tsuboka and Katayama (T–K–Wilson) and UNIQUAC equation. The interaction parameters of T-KWilson and UNIQUAC G E models for three binary systems have been determined from LLE data points at 0.1 MPa. The prediction ability of the models has been evaluated by comparison of the results with experimental data. Average Absolute Error (AAE) of 0.047 for MHV1 and T–K–Wilson model, 0.0117 for MHV2 and T–K–Wilson model, 0.0317 for MHV1 and UNIQUAC model and 0.0109 for MHV2 and UNIQUAC model have been obtained. As it is clear, the combination of MHV2 excess Gibbs mixing rule with UNIQUAC equation shows a satisfactory agreement with experimental data.

methods

High-pressure vapor-liquid equilibrium with a UNIFAC-based equation of state

Prediction of liquid-liquid equilibria of binary systems containing alcohols using eos-ge models

This paper investigates the use of infinite-dilution activity coefficients to define the interaction parameters of the Redlich-Kwong equation of state (SRK-EOS), with the Huron-Vidal mixing rules. The group-contributions of a UNIFAC-type model were regressed from experimental infinitedilution activity coefficients of a number of significant systems, including strongly polar components. Such parameters were then used to predict vapor-liquid equilibria (VLE) over the whole composition range, at pressures up to 6 MPa, with generally good results.

High-pressure vapor-liquid equilibrium with a UNIFAC-based equation of state

Citations

Prediction of liquid-liquid equilibria of binary systems containing alcohols using eos-ge models

Equation-of-State Group Contributions from Infinite-Dilution Activity

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