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Abstract In this work, the COSMO-SAC-Phi equation of state [Fluid Phase Equilib. 488 (2019) 13–26] is refined by the introduction of a new equation to describe dispersive effects. The proposed… Click to show full abstract
Abstract In this work, the COSMO-SAC-Phi equation of state [Fluid Phase Equilib. 488 (2019) 13–26] is refined by the introduction of a new equation to describe dispersive effects. The proposed modification is inspired by the well-known rules of consistency for α -functions, used in cubic equations of state. The results for 38 representative compounds have shown that the proposed modification is able to improve the correlation of pure compound experimental data of saturation pressures and saturated liquid volume, with average deviations of 0.96% and 0.73%, respectively. Densities of pure compounds under conditions beyond the saturation region were also well predicted. Vapor-liquid equilibrium predictions of binary mixtures demonstrated, for most cases, that the modified equation was superior to the original COSMO-SAC-Phi model, PSRK, and Soave-Redlich-Kwong with the classical van der Waals mixing rule. The modified model was also able to produce very good predictions for liquid-liquid equilibrium, being similar to UNIFAC-LLE at low temperatures, but exhibiting a much better performance at higher temperatures (and pressures).