Correlation and prediction of liquid–liquid equilibria for alcohol/hydrocarbon mixtures using PC-SAFT equation of state at high pressure up to 150 MPa

In this paper, we present a systematic study of the ability of the PC-SAFT equation of state to predict of liquid–liquid equilibria (LLE) for alcohol/hydrocarbon mixtures at high pressure on the basis of LLE data at 0.1 MPa. The adjustable temperature-independent binary interaction parameters, kij, in the PC-SAFT model were determined from LLE data at 0.1 MPa. The new proposed parameters set for methanol and ethanol with the two-site association scheme reproduce vapor pressures and liquid density with the same accuracy of PC-SAFT original parameters but show a better representation of the LLE data. In addition to using pure component PC-SAFT parameters derived from the standard method of fitting to liquid density and saturated vapor pressure, the new PC-SAFT parameters set for methanol and ethanol are determined from experimental association energy. The new association energy parameter of methanol and ethanol shows better agreement with the experimental results at approximately 298 K compared to all previously published PC-SAFT parameters.Different binary methanol + hydrocarbon and ethanol + hydrocarbon systems at high pressure up to 150 Mpa were tested using the PC-SAFT. LLE calculations and prediction show good agreement with experimental data for almost considered systems.

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