Extension of 2C Association Scheme to Polyols Phase Equilibria

Abstract

The application of the 2C association scheme proposed by De Villiers et al. (Ind. Eng. Chem. Res. 2011 50, 8711–8725) in the association term of cubic plus association equation of state (CPA EoS) is extended to polyol containing systems to correlate the binary and predict the ternary mixtures. First, the CPA parameters of pure components were successfully adjusted by vapor pressure and saturated liquid density experimental data. Then, the performance of the aforementioned scheme is compared to the other classical schemes by modeling the vapor–liquid equilibria (VLE) and liquid–liquid equilibria (LLE) of binary {polyol/small alcohol}, {polyol/water}, {fatty acid ester/small alcohol}, and {polyol/alkane} and ternary {small alcohol/poyol/fatty acid ester} and {small alcohol/water/poyol} mixtures. Applying a simple and robust phase equilibria algorithm proposed by Privat et al. (Comput.Chem. Eng. 2013, 50, 139–151) to binary and ternary systems, the VLE and LLE correlative performance of CPA EoS coupled with various combined schemes are very satisfactory over extensive temperature ranges and shows that each model is within or close to experimental uncertainty. Then, using two temperature-independent binary interaction parameters (BIPs) fitted with binary VLE and LLE data, the predictive performance of different models is further evaluated in ternary systems phase equilibria (LLE and VLE), and acceptable results are achieved at different temperatures. Eventually, it has been demonstrated that 2C scheme exhibits remarkable precision in predicting the VLE and LLE of polyol containing systems.