Pilot Scale Chromatographic Separation of Poly Unsaturated Ethyl Esters Using Liquefied Gases and Supercritical Fluids

This paper describes the scale-up, development and commissioning of a pilot scale preparative chromatography plant suitable for use with liquefied gases and supercritical fluids as the mobile phase, including the use of flammable gases. The pilot plant has 2 by 10L columns capable of operation up to 350 bar pressure and 85°C temperature. The columns can be operated in series or independently, and in single or semi-continuous automated operation. A UV-Vis detection system is used, and up to 4 fractions can be separately recovered. A co-solvent gradient can also be applied.

A laboratory scale process for separation of the polyunsaturated fatty acids EPA and DHA from mixtures of ethyl esters derived from fish and algal sources has been developed, and a comparison of results between laboratory and pilot scale is given. Very good separation, exceeding 90% concentration of EPA and DHA, and very good recovery was able to be achieved in a single pass operation using CO₂ as the mobile phase and a silica column. Conditions were optimised over the range 150 to 250 bar pressure, temperatures from 40 to 60°C, and using a range of ethyl ester and CO₂ flow rates. Results were able to be reproduced on the pilot scale using loadings between 10g and 100g of ethyl esters.