PHASE-EQUILIBRIA OF SUPERCRITICAL CO2 - FATTY OIL COMPONENT BINARY-SYSTEMS

With the aim of separating fatty acids and triglycerides of different carbon numbers, fluid - liquid equilibria of supercritical CO2 - fatty acid(C6, C12, C16) and supercritical CO2 - triglyceride(C24, C36, C48) binary systems were measured using a static type apparatus for the temprature range of 313K-353K and pressures up to 30 MPa. For both fatty acids and triglycerides, the solubility decreases with total carbon number of the compound, showing that they can be fractionated based on their carbon number using supercritical carbon dioxide. The measured fluid - liquid equilibrium data were correlated by a lattice-fluid EOS proposed by Kumar et al. and the commonly used Peng-Robinson EOS. The lattice-fluid EOS correlated both the liquid and vapor phases well compared to the Peng-Robinson EOS. The regressed binary interaction parameter of the latitce model EOS was found closely related to the total carbon number of fatty acids and triglycerides. Above results suggest that to establish a method to evaluate the interaction and size parameters of fatty oil components is required for developing a phase equilibrium prediction model for the supercritical CO2.- fatty oil component systems based on the lattice - fluid EOS.