Investigation of phase equilibria in the ternary system carbon dioxide + 1-heptanol + n-pentadecane

Isothermal vapor–liquid equilibria measurements for binary and ternary mixtures containing carbon dioxide, 1-heptanol, and n-pentadecane at the temperatures of 298.15 and 316.15 K are reported. Phase equilibria measurements were made in a high-pressure visual cell with variable volume based on the static-analytical method. Both binary systems exhibit type III phase behavior, according to the classification of van Konynenburg and Scott. The phase equilibrium in the binary systems was correlated with the Soave–Redlich–Kwong (SRK) equation of state coupled with the Huron–Vidal infinite dilution (HVID) mixing rules. The parameters for the binary mixtures are further used to predict the phase equilibria of the ternary system n-pentadecane + 1-heptanol + carbon dioxide. Validation of the predictions was achieved by comparison with experimental results. The model has the capability to predict the cosolvency effect.