Estimation of phase behavior in mixtures of CO₂ and C₂₀+ n-alkanes using predictive eos models

Abstract

The present study compares the ability of Global Phase Diagram Approach (GPDA) and Linear Combination of the Vidal and Michelsen mixing rules (LCVM) to predict equilibrium compositions and molar volumes in mixtures of CO₂–n-eicosane and heavier homologues. LCVM should be characterized as correlative rather than predictive model because its parameters have been evaluated by fitting the data of homologues up to n-octacosane. In contrast, GPDA appears as entirely predictive model because it does not resource to any experimental data of systems under consideration. Nevertheless, GPDA is much more accurate than LCVM in predicting data. These results emphasize the robustness of GPDA and evidence about its reliability for predicting of data are not available experimentally.

Keywords:

• Supercritical
• n-Alkanes
• Equation of state
• Global phase diagram

Acknowledgments

This work was financed by the Israel Science Foundation, Grant Number 340/00 and by FONDECYT, Santiago, Chile (Project 2010100).