Continuous concentration of EPA and DHA from fish oil by supercritical CO₂

In order to overcome the disadvantages of a batch flow, a continuous flow was designed to concentrate EPA and DHA from fish oil by supercritical CO₂ extraction technology in packed-tower with a diameter of 14 mm and a padding height of 1.8 m. Then, on the basis of single-fact experiments, the technological parameters were optimized by orthogonal tests which include 3 factors and 4 levels, with the consideration of interaction among 3 factors, in which a comprehensive index was used as a test target. The results showed that the optimum column pressure was 12.5 MPa, temperature distribution was 40～85℃, CO₂ flow 5 L/min, and fish oil feed flow was 0.8 mL/min. It was found that the temperature distribution factor was very prominent, followed by the factor of fish oil feed flow. The effects of pressure and CO₂ flow, as well as the interactive effects among pressure and temperature distribution, temperature distribution and CO₂ flow, and pressure and CO₂ flow were not prominent.