Thermodynamic Modeling and process optimization of supercritical fluid fractionation of fish oil fatty acid ethyl esters

Rigorous thermodynamic modeling, simulation, and optimization of the supercritical fractionation of EPA and DHA esters is presented. These valuable products are obtained from complex mixtures of fish oil fatty acid alkyl esters by high-pressure fractionation with supercritical carbon dioxide. A group contribution equation of state (GC-EOS) that provides reliable phase equilibrium and solubility predictions is used to support the process simulation. A correlation has been developed for the estimation of a thermodynamic model parameter: the fish oil esters hard-sphere diameter. The capability of the group contribution equation of state is confirmed by a detailed comparison of predictions with experimental data. Rigorous simulation models for process units have been formulated within a nonlinear optimization model to maximize EPA and DHA esters recovery and purity from several natural fish oil mixtures with supercritical extraction.