Phase equilibrium for the extraction of squalene from shark liver oil using supercritical carbon dioxide

Phase equilibrium data were required for extracting squalene from shark Liver oil which contains triglycerides and glyceryl ethers as the other major components. Vapor/liquid equilibrium for the binary system squalene/carbon dioxide was measured over the pressure range 100-250 bar and temperature range 313-333 K using a continuous-packed column method. The solubility of squalene in the vapor phase was correlated using a simple density-based equation. Phase equilibria for both squalene/carbon dioxide and a model triglyceride/carbon dioxide system were correlated using the Peng-Robinson equation of state. The Peng-Robinson attraction and repulsion parameters for carbon dioxide were optimized to reproduce known carbon dioxide density at a given temperature and pressure. Using this approach it was possible to accurately correlate vapor/liquid equilibria and phase densities for both carbon dioxide/squalene and carbon dioxide/triglyceride binary systems and predict vapor/liquid equilibria and phase densities for the three-component mixture over the same temperature and pressure range as the experimental data. The interaction parameters required were very small, which suggests that previously reported deficiencies in the modeling of phase equilibria for components with widely varying sizes may be due to the inaccurate attraction and repulsion parameters used for the light (carbon dioxide) component.