(64e) Phase Behavior of Complex Systems Using the GC-SAFT-VR Equation of State

The statistical associating fluid theory [1] is a commonly used molecular-based equation of state that has been successfully applied to study a wide range of fluid systems. In recent work, the GC-SAFT-VR [2] equation that combines the SAFT equation for potentials of variable range (VR) with a group contribution like approach was proposed, and has been shown to provide an excellent description of the phase behavior of pure non-associating fluids and their mixtures. The parameters for key functional groups (such as CH₃, CH₂, CH, CH₂=CH, C=O, C₆H₅, ether and ester, OH, NH₂, CH=O, COOH) were obtained by fitting to experimental vapor pressure and saturated liquid density data for selected low molecular weight fluids. In this work, the transferability of these parameters is tested by comparing the theoretical predictions with experimental data for pure fluids not included in the fitting process and their binary mixtures. The GC-SAFT-VR approach is found to accurately predict the phase behavior of the systems studied without adjusting the group parameters to binary mixture data.

[1] Chapman et al. Fluid Phase Equilibria 52, 31-38 (1989); Chapman et al. Industrial & Engineering Chemistry Research 29(8), 1709-1721 (1990). [2] Peng et al. Fluid Phase Equilibria 277(2), 131 (2009).