Preparation of fatty acid esters of primary or secondary alcohols, used in production of bio-diesel, from unpurified oil containing fatty acids and sludge involves acid catalysis, base catalysis and glycerin separation

摘要

Preparation of fatty acid esters of prim. or sec. alcohols from unpurified oil containing fatty acids and sludge comprises: (i) acid catalysis of the esterification of free fatty acids and deactivating the sludge components in a raw oil or fat or recycled oil using a hygroscopic acid catalyst; (ii) base-catalyzed reaction of the glycerin-bound fatty acids to esters using an alkaline catalyst; and (iii) separating off the glyceryl phase.