Patent ID: 7109363
Filing Date: 2006-09-19
Classification: B01D,C11B,C11C

Abstract:
1. Method of producing fatty acid esters of primary and/or secondary alcohols from raw unpurified oils and fats containing free fatty acids and slimy substances, or from waste oils loaded with free fatty acids from the food industry using alkaline catalyzed transesterification under formation of a separable glycerol phase and an acidic catalyzed esterification of free fatty acids preceding the transesterification, characterized in that a. first the acidic catalyzed esterification of the free fatty acids together with deactivation of slimy substances being present is performed with regard to the disadvantageous emulsion-forming properties thereof in that a water-free primary and/or secondary alcohol and a strongly acidic hygroscopic catalyst are added to the starting substance in form of the raw oil or fat or waste oil, respectively, wherein the added amount of water-free alcohol at least corresponds to the amount being stoichiometrically necessary for complete ester formation of the free fatty acids contained in the starting substance, b. that the reaction product of the acidic-catalyzed esterification is washed with the separated glycerol of an alkaline transesterification process having already been performed and the glycerol wash phase is subsequently separated, c. that the reaction product of the acidic-catalyzed esterification, having been washed in this manner, is subjected to said alkaline-catalyzed transesterification in that an alkaline catalyst and the amount of alcohol required for transesterification of the glyceridically bound fatty acids into fatty acid esters are added to said reaction product, and d. that the glycerol phase formed in step c. is separated from the esters of the free fatty acids and of the fatty acids present in glyceridically-bound form in the starting substance, having been formed in steps a. and c.