Patent ID: 7420072

Claim:
A process for the production of biodiesel grade, fatty acid alkyl esters comprising: (a) reacting triglyceride, alcohol and catalyst in a first reaction zone to form a first intermediate reacted mixture which includes trans-esterified fatty acid ester product, glycerol, unreacted alcohol, and unreacted and partially reacted triglyceride; (b) removing glycerol and unreacted alcohol from the first intermediate reacted mixture to form a second intermediate reacted mixture; (c) feeding the second intermediate reacted mixture to a second reaction zone; (d) adding a fresh feed of alcohol and catalyst into the second reaction zone to form fatty acid alkyl esters and glycerol from the second intermediate reacted mixture to form a third intermediate reacted mixture; (e) separating alcohol, glycerol and a fraction of the fatty acid alkyl esters from the third intermediate reacted mixture to produce a recycle stream; and (f) recycling alcohol, glycerol and fatty acid alkyl esters recovered from said recycle stream from the third intermediate reacted mixture to the first reaction zone in an amount sufficient to act as a co-solvent of the reaction process, and further, wherein said recycle stream includes at least 20% by volume of alkyl ester.