Biodiesel production using ultra low catalyst concentrations in a membrane reactor

A method of producing fatty acid alkyl esters, comprising:

• mixing triglyceride and an alcohol as an oil-in-alcohol emulsion together with a catalyst, forming a reaction mixture for converting the triglyceride to said fatty acid alkyl esters;
• reacting the triglyceride and alcohol in the presence of the catalyst by continuously circulating said reaction mixture in a continuous loop reactor, to produce said fatty acid alkyl esters;
• and
• flowing the reaction mixture past a cross-flow selective membrane in the continuous loop reactor, said selective membrane permitting passage of said fatty acid alkyl esters while excluding passage of triglyceride, to continuously remove from the reaction mixture said fatty acid alkyl esters formed in the step of reacting, to produce said fatty acid alkyl esters;
• while retaining unreacted triglyceride within the reaction mixture in the continuous loop reactor;
• wherein said catalyst is present in the reaction mixture at a concentration below a conventional concentration of 1.0 wt %.