Comparison of the performance of the LCVM model (an EoS/GE model) and the PHCT EoS (the Perturbed Hard Chain Theory Equation of State) in the prediction of the Vapor–Liquid Equilibria of binary systems containing light gases

The purpose of this work is to compare two models, which are able to perform Vapor–Liquid Equilibrium (VLE) predictions. The first one, the LCVM model, is an EoS/GE one and it has been successfully applied in the prediction of the VLE behavior of polar and non-polar systems, as well as, systems of dissimilar component size, such as those containing gases with large n-alkanes. The second one is PHCT, an equation of state based on the perturbed hard chain theory. It has also been successfully applied in binary systems of supercritical fluids and non-polar molecules and in systems containing light gases and large n-paraffins. The comparisons results presented in this paper, proved that the two models are comparable, concerning the ability to predict the VLE, as well as, the volumetric behavior of systems with low to medium component size difference (supercritical fluids with non-polar components up to about 10 carbon atoms). However, as the size difference increases, LCVM performs better, especially in the near critical region of such systems.