Abstract: The glycerol water (sweet water) accumulating in the high-pressure hydrolysis of natural fats and oils with steam into fatty acid and glycerol is continuously purified. Fats larger than 100 .mu.m in diameter are separated from the aqueous phase in a plate-type phase separator and are returned to the high-pressure hydrolysis process. The aqueous phase thus prepurified is passed through a cross-flow filtration membrane, more particularly a microfiltration membrane, and the concentrate is returned to the entrance of the plate-phase separator. Large product streams of glycerol water can be purified continuously, effectively and particularly economically despite frequent changes of provenance.

Abstract: An improved process for purification of glycerol obtained from natural sources comprising alkalizing a glycerol-containing crude mixture in the presence of air for oxidation, evaporating the mixture in a thin-layer evaporator with redistillation of the residue, rectification and reevaporation in a packed column characterized by low-pressure-loss plates with a falling-film evaporator designed for internal and external partial condensation and to separate off unwanted constituents of the mixture, bleaching the product with activated carbon and separating the bleach in known manner.