Fractionation of fatty acid ethyl esters by supercritical CO2:: high separation efficiency using an automated countercurrent column

Supercritical fluid extraction of fatty acid ethyl esters with CO, was carried out using a column with an inner diameter of 35 mm and a packing height of 13.6 m (Sulzer CY). The column was automated so that the process could be constantly supervised. Automation led to a steady state operation that resulted in increased gas cross-section load (CSL), compared with a non-automated column of the same height and packing, but with an inner diameter of 65 mm. The highest CSL reached at 333 K and 14.5 MPa was 93 000 kg/(m(2)/h). A sharp separation according to the chain length of fatty acid ethyl esters was possible with impurities of the respective other fraction of 0.3 wt.%. Although a decrease of the CSL with increased temperature was found, an enhanced feed turnover was feasible. (C) 1998 Elsevier Science B.V. All rights reserved.