Mobile processing systems and methods for producing biodiesel fuel from waste oils

A process for producing biodiesel fuel, said process comprising:

• (a) providing a feed stream comprising glycerides and free fatty acids;
• (b) optionally filtering out at least a portion of solids contained in said feed stream;
• (c) introducing said feed stream and an alcohol into a first reactor, operated at effective first reaction conditions and including a first effective esterification and transesterification catalyst, or mixture of such catalysts, to react at least a portion of said free fatty acids with said alcohol to produce fatty acid alkyl esters and water, and to react at least a portion of said glycerides with said alcohol to produce fatty acid alkyl esters and glycerin, thereby producing a first intermediate stream comprising fatty acid alkyl esters, glycerin, water, and alcohol;
• (d) introducing at least a portion of said first intermediate stream to a first separator operated to remove at least some glycerin, water, and alcohol, thereby producing a second intermediate stream comprising fatty acid alkyl esters and unreacted free fatty acids;
• (e) introducing said second intermediate stream and an alcohol to a second reactor, operated at effective second reaction conditions and including a second effective esterification and transesterification catalyst, or mixture of such catalysts, to react free fatty acids contained therein with said alcohol to produce fatty acid alkyl esters and water, and/or to react glycerides contained therein with said alcohol to produce fatty acid alkyl esters and glycerin, thereby producing a third intermediate stream comprising fatty acid alkyl esters, glycerin, water, and alcohol;
• (f) introducing at least a portion of said third intermediate stream to a second separator operated to remove at least some glycerin, water, and alcohol, thereby producing a fourth intermediate stream comprising fatty acid alkyl esters and unreacted free fatty acids;
• and
• (g) introducing said fourth intermediate stream and a base to a fatty acid alkyl ester recovery unit operated to contact said base with said unreacted free fatty acids to produce a fatty acid-base complex, and separate said fatty acid-base complex from said fatty acid alkyl esters, thereby generating a crude product stream comprising said fatty acid alkyl esters.

A process for producing biodiesel fuel, said process comprising:

• (a) providing a feed stream comprising glycerides and free fatty acids;
• (b) optionally filtering out at least a portion of solids contained in said feed stream;
• (c) introducing said feed stream and an alcohol into a membrane reactor configured with immobilized esterification and transesterification enzymes supported on membranes, wherein said membrane reactor is operated at effective reaction conditions to react at least a portion of said free fatty acids with said alcohol to produce fatty acid alkyl esters and water, and to react at least a portion of said glycerides with said alcohol to produce fatty acid alkyl esters and glycerin, thereby producing an in situ mixture comprising fatty acid alkyl esters, glycerin, water, and alcohol;
• and wherein said membrane reactor, under effective reaction conditions, continuously separates at least some glycerin, water, and alcohol, thereby producing an intermediate stream comprising fatty acid alkyl esters and unreacted free fatty acids;
• (d) optionally further reacting, separating, or treating said intermediate stream;
• and
• (e) introducing said intermediate stream and a base to a fatty acid alkyl ester recovery unit operated to contact said base with said unreacted free fatty acids to produce a fatty acid-base complex, and separate said fatty acid-base complex from said fatty acid alkyl esters, thereby generating a crude product stream comprising said fatty acid alkyl esters.