Comparative Study of Phase Equilibrium Modeling with Cubic and Association Equations of State

Abstract

Cubic and association equations of state are two of the most widely used types of thermodynamics models. In this work, we focused on comparing the predictive capabilities of three equations of state, namely, the original Peng–Robinson, the perturbed-chain SAFT, and SAFT-VR Mie, for modeling phase equilibria of diverse types of systems. Vapor–liquid equilibria predictions from these three equations of state were evaluated using a recently published benchmark database of 200 binary systems. In addition, we compared their capabilities in predicting the liquid–liquid equilibria of ternary mixtures and vapor–liquid equilibria of a quaternary mixture. The general conclusion is that the SAFT-VR Mie equation of state presents the best performance from an overall viewpoint, but the Peng–Robinson and perturbed-chain SAFT equations of state show respectively superior performance for some specific types of systems.