Proof of UNIQUAC Activity Coefficient Model for Water-Monoethanolamine System by Gibbs-Duhem Equation Department of Chemical Engineering, Faculty of Engineering, Prince of Songkla University

Abstract

The UNIQUAC activity coefficient model can predict vapor-liquid  equilibrium between water and monoethanolamine (C₂H₇NO,MEA) efficiently. The model needed the energy interaction parameters between molecules of water and monoethanolamine. Those parameters can be obtained by non-linear regression method of the experimental data of the vapor-liquid equilibrium systems of water and monoethanolamine. The experimental data have ranges of temperature and mole fraction of monoethanolamine between 25 to 92ºC and 0 to 1 respectively. The parameters are temoerature dependent but are not concentration dependent. The parameters are temperature dependent but are not concentration dependent. The regression results are in good agreement with the experimental data in that the percent error of calculated partial pressure of monoethanolamine is 6.21. The thermodynamic consistency test with Gibbs-Duhem equation is in good agreement in that the sum of derivative of activity coefficients with respect to mole fraction of monoethanolamine is equal to zero