Thermodynamic consistency of experimental VLE data for asymmetric binary mixtures at high pressures

Abstract

A thermodynamic consistency of isothermal vapor-liquid equilibrium data for 9 non-polar and 8 polar binary asymmetric mixtures at high pressures has been evaluated. A method based on the isothermal Gibbs-Duhem equation was used for the test of thermodynamic consistency using a Φ-Φ approach. The Peng-Robinson equation of state coupled with the Wong-Sandler mixing rules were used for modeling the vapor-liquid equilibrium (VLE) within the thermodynamic consistency test. The VLE parameters calculations for asymmetric mixtures at high pressures were highly dependent on bubble pressure calculation, making more convenient to eliminate the data points yielding the highest deviations in pressure. However the results of the thermodynamic consistencies test of experimental data for many cases were found not fully consistent. As a result, the strategies for solving these problems were discussed in detailed. © 2010 Elsevier B.V. All rights reserved.