Methods and compositions for refining lipid feed stocks

Abstract

The present invention relates to systems and methods of using fatty acid alkyl ester solutions to refine feed stocks before converting the feed stocks into fatty acid fatty acid alkyl esters. In an embodiment, the invention includes a method for producing fatty acid alkyl esters. The method can include mixing a crude lipid feed stock with a refining solution to form a crude product mixture, the refining solution comprising greater than about 10 wt. % fatty acid alkyl esters. The method can include extracting the liquid phase from the crude product mixture to obtain a purified lipid feed stock. The method can also include reacting the purified lipid feed stock with an alcohol to form a product mixture comprising fatty acid alkyl esters. In an embodiment, the invention includes a method of making a fatty acid alkyl ester composition. The method can include extracting lipids from a corn-based ethanol production byproduct, adding an alcohol solution to the lipids to form a reaction mixture, and contacting the reaction mixture with a metal oxide catalyst. Other embodiments are included herein.

1 - 20 . (canceled) 
     
     
         21 . A method of making a fatty acid alkyl ester composition, the method comprising:
 extracting a lipid mixture from a byproduct; wherein the lipid mixture has an acid number of about 3 (mg KOH/g oil) or greater;   adding an alcohol solution to the lipids to form a reaction mixture; and   contacting the reaction mixture with a metal oxide catalyst.   
     
     
         22 . The method of  claim 21 , wherein extracting the lipid mixture from the byproduct comprises centrifuging the byproduct. 
     
     
         23 . The method of  claim 21 , wherein contacting the reaction mixture with a metal oxide catalyst is performed under supercritical conditions for the alcohol. 
     
     
         24 . The method of  claim 21 , wherein contacting the reaction mixture with a metal oxide catalyst is performed at a temperature of between about 350 and 400 degrees Celsius. 
     
     
         25 . The method of  claim 21 , wherein contacting the reaction mixture with a metal oxide catalyst is performed at a pressure of between about 1500 and 5000 psi. 
     
     
         26 . The method of  claim 21 , the metal oxide catalyst comprising a material selected from the group consisting of zirconia, titania, hafnia, and alumina. 
     
     
         27 . The method of  claim 21 , the metal oxide catalyst comprising a material selected from the group consisting of zirconia and titania. 
     
     
         28 . The method of  claim 21 , the metal oxide catalyst comprising an unmodified metal oxide. 
     
     
         29 . The method of  claim 21 , the metal oxide catalyst consisting essentially of an unmodified metal oxide selected from the group consisting of alumina, titania, zirconia, and hafnia. 
     
     
         30 . The method of  claim 21 , the metal oxide catalyst consisting essentially of titania. 
     
     
         31 . The method of  claim 21 , the metal oxide catalyst comprising particles with an average particle size of about 0.2 microns to about 2 millimeters. 
     
     
         32 . The method of  claim 21 , the metal oxide catalyst comprising particles with an average particle size of about 1 μm to about 100 μm. 
     
     
         33 . The method of  claim 21 , the alcohol comprising a C1-C6 alcohol. 
     
     
         34 . The method of  claim 21 , wherein contacting the reaction mixture with a metal oxide catalyst is performed with a residence time of less than about 60 seconds. 
     
     
         35 . A method of making a fatty acid alkyl ester composition, the method comprising:
 extracting lipids from an agricultural production byproduct;   adding an alcohol solution to the lipids to form a reaction mixture; and   contacting the reaction mixture with a metal oxide catalyst.   
     
     
         36 . The method of  claim 35 , wherein contacting the reaction mixture with a metal oxide catalyst is performed under supercritical conditions for the alcohol. 
     
     
         37 . The method of  claim 35 , wherein contacting the reaction mixture with a metal oxide catalyst is performed at a temperature of between about 350 and 400 degrees Celsius. 
     
     
         38 . The method of  claim 35 , wherein contacting the reaction mixture with a metal oxide catalyst is performed at a pressure of between about 1500 and 5000 psi. 
     
     
         39 . The method of  claim 35 , the metal oxide catalyst comprising a material selected from the group consisting of zirconia, titania, hafnia, and alumina.