Study of the high pressure phase behaviour of CO2+n-alkane mixtures using the SAFT-VR approach with transferable parameters

Abstract

The statistical associating fluid theory for potentials of variable range (SAFT-VR) is used to examine the phase behaviour in the CO2 + n-alkane homologous series. A unique set of transferable parameters for the unlike inter- actions are used which allow the prediction of the phase behaviour of different members of the series with little experimental data. A change in phase behaviour from type II in the van Konynenburg scheme (continuous gas–liquid critical line and liquid–liquid immiscibility at low temperatures) for CO2 + n-dodecane, to type IV (discontinuous gas–liquid critical line and liquid–liquid immiscibility) for CO2 + n-tridecane, and to type III (continuous transi- tion from gas–liquid to liquid–liquid critical behaviour) for CO2 + n-tetradecane is observed in agreement with experimental data.