Patent ID: 7126032

Claim:
A process for purifying glycerin recovered from a fatty acid alkyl ester process, comprising: providing a crude glycerin stream recovered from fatty acid alkyl ester production, the crude glycerin stream comprising: glycerin, at least one low molecular weight alcohol, at least one glyceride, at least one fatty acid ester of a low molecular weight alcohol and water, heating the crude glycerin stream to a temperature of from about 125° C. to about 160° C., feeding the crude glycerin stream to a first reactor maintained at about 125° C. to about 160° C., wherein at least a portion of the at least one fatty acid alkyl ester contained in the crude glycerin stream undergoes a transesterification with glycerin to produce additional amounts of the at least one low molecular weight alcohol and additional glyceride, in the first reactor, sparging the crude glycerin stream with nitrogen, thereby stripping a portion of the at least one low molecular weight alcohol and water from the crude glycerin stream, to produce a first glycerin effluent stream, feeding the first glycerin effluent stream from the first reactor to a second reactor maintained at about 120° C. to about 160° C., in the second reactor, sparging the first effluent stream with nitrogen, thereby stripping the at least a portion of the at least one low molecular weight alcohol and a portion of the water, to produce a second effluent stream comprising glycerin, at least one glyceride and water; distilling the second glycerin effluent stream in a flash distillation column wherein water and glycerin are vaporized and removed as an overhead stream.