To refined biological diesel oil by supercritical fluid extraction can emerge the residue of biodiesel catalyst, lecithin, glycerin, sterol. At the same time, the
biodiesel technology combined the technology of supercritical fluid fractionation adsorption removal other glyceride, compared with vacuum distillation technology can reduce energy consumption, and supercritical extraction separation of impurities is complete. In addition, the kettle bottom material can be obtained by separating the refined phytosterol high value-added products, reducing the production cost of biodiesel.
In addition, supercritical technology will produce fatty acid ester in a near critical extraction solvent extraction from the reaction mixture, the selection of extraction agent is carbon dioxide, propane, butane, dimethyl ether, ethyl acetate, or their mixture, the resulting high fatty acid ester yield and high purity. The disadvantage is that, compared with the methods of vacuum distillation, molecular distillation, supercritical fluid extraction technology of biodiesel production on a smaller scale, its production cost is higher, in the case of the same size bigger investment. So the supercritical fluid extraction technology is more suitable for high value-added biodiesel and small scale of the separation of matter.
