Simultaneous modeling of VLE, LLE and VLLE of CO2 and 1, 2, 3 and 4 alkanol containing mixtures using GC-PPC-SAFT EOS
Résumé
A polar version of the group contribution PC-SAFT equation of state (GC-PPC-SAFT; Tamouza et al., 2004; NguyenHuynh et al., 2008) combined with a method for correlation/prediction of binary interaction parameters kij (NguyenHuynh et al., 2008) is here applied to model vapor–liquid, liquid–liquid and vapor–liquid–liquid phase equilibria of CO2 + alkanol mixtures simultaneously.
A cross-association interaction between CO2 and alkanol had to be taken into account to model/predict the mixtures equilibria accurately. The cross-association parameters were evaluated using the so-called CR1 mixing rules supported by ab initio computations.
Extensive prediction tests on CO2 + alkanol mixtures involving linear and branched alkanols are carried out. The results obtained showed that in most cases, the correlation and prediction calculations are qualitatively and quantitatively satisfactory: the overall deviations on liquid phase and vapor phase are respectively ΔX = 3–4% and ΔY = 1–2%.