Method of producing biodiesel fuel

Abstract

A method of producing biodiesel fuel from fats and oils includes a step of transesterification reaction in which fats and oils are transesterfied with lower alcohol, a step of fuel refining in which a resultant fatty acid alkyl ester produced in said transesterfication reaction step is refined, and a mixing step in which the fatty acid alkyl ester refined in the fuel refining step is mixed with light oil. The refined fatty acid alkyl ester is heated to a predetermined temperature and thus fused so as not to oxidize unsaturated fatty acids contained in the fatty acid alkyl ester, while the heated and refined fatty acid alkyl ester is mixed with light oil so as not to set the temperature of the mixed solution below the cold filter plugging point during the mixture, to dilute the fatty acid alkyl ester by light oil to a predetermined weight ratio.

1 . A method of producing biodiesel fuel from fats and oils comprising:
 (i) transesterifying fats and oils with lower alcohol to produce a fatty acid alkyl ester;   (ii) refining the fatty acid alkyl ester;   (iii) heating the refined fatty acid alky ester to fuse the refined fatty acid alky ester; and   (iv) mixing the fused fatty acid alkyl ester with light oil to produce a mixed solution,   wherein step (iii) comprises heating the refined fatty acid alkyl ester to a temperature such that a temperature of the mixed solution during step (iv) becomes equal to or higher than its cold filter plugging point (CFPP) but lower than a temperature at which unsaturated fatty acids contained in the fused fatty acid alkyl ester are substantially oxidized.   
     
     
         2 . The method according to  claim 1 , wherein step (iv) is subdivided into multiple steps and performed at substantially or nearly an ambient temperature step-by-step. 
     
     
         3 . The method according to  claim 1 , wherein step (iii) is performed under a substantially sealed condition to substantially block air and/or light. 
     
     
         4 . The method according to  claim 1 , wherein the lower alcohol is methyl alcohol. 
     
     
         5 . The method according to  claim 1 , wherein the fats and oils is one material selected from plants and animals. 
     
     
         6 . The method according to  claim 5 , wherein the fats and oils is palm oil. 
     
     
         7 . The method according to  claim 1 , further comprising removing solids and/or water from the fats and oils by gravity separation. 
     
     
         8 . The method according to  claim 1 , wherein step (i) is performed using a non-oxidizing catalyst. 
     
     
         9 . The method according to  claim 8 , wherein the non-oxidizing catalyst is potassium hydroxide. 
     
     
         10 . The method according to  claim 1 , wherein step (ii) further comprises filling a container with the refined fatty acid alkyl ester and storing the refined fatty acid alkyl ester in solid form within the container under a sealed condition, and step (iii) comprises heating the solid fatty acid alkyl ester from outside the container while the container is sealed, thereby fusing the the solid fatty acid alkyl ester.