Production of Biodiesel Fuels Which Are Low in Glycerin and Sulfur

Abstract

The present invention relates to a process and apparatus for the production of carboxylic acid esters and/or biodiesel fuel from feedstocks containing fatty acids, glycerated fatty acids, and glycerin by reactive distillation. Specifically, in one embodiment, the present invention relates to the production of biodiesel fuels having low glycerin, water, and sulfur content on an industrial scale.

What is claimed:  
     
         1 . A method comprising:
 continuously esterifying, in a reaction vessel, a fatty acid feedstream with an alcohol vapor in the presence of a catalyst to produce a fatty acid alkyl ester product stream and water,   removing the water from the reaction vessel with the alcohol vapor;   converting said fatty acid alkyl ester product stream into a biodiesel meeting biodiesel standard ASTM D6751.   
     
     
         2 . The method of  claim 1 , wherein the catalyst comprises as heterogeneous catalyst. 
     
     
         3 . The method of  claim 2 , wherein the catalyst comprises an ion exchange resin catalyst with —SO 3 H or —CO 2 H functional groups. 
     
     
         4 . The method of  claim 1 , wherein the alcohol vapor is selected from the group consisting of methanol, ethanol, propanol, isomers of propanol, isomers of butyl and amyl alcohol, isoamyl alcohol, and mixtures thereof. 
     
     
         5 . The method of  claim 4 , wherein the alcohol vapor is methanol. 
     
     
         6 . The method of  claim 4 , wherein the alcohol vapor is ethanol. 
     
     
         7 . The method of  claim 1 , wherein said convening comprises removing impurities from said fatty acid alkyl ester product stream by at least one purification process selected from the group consisting of distillation, reboiled stripping, inert gas snipping, physical adsorption, and gravity separation. 
     
     
         8 . The method of  claim 1 , further comprising separating the water from the alcohol vapor. 
     
     
         9 . The method of  claim 8 , further comprising recycling the alcohol vapor to the reaction vessel. 
     
     
         10 . The method of  claim 1 , wherein the fatty acid alkyl ester product stream comprises fatty acid methyl esters. 
     
     
         11 . The method of  claim 1 , wherein the fatty acid alkyl ester product stream comprises fatty acid ethyl esters. 
     
     
         12 . The method of  claim 1 , wherein the fatty acid feedstream is the product of introducing a triglyceride feedstock into a fat splitter. 
     
     
         13 . The method of  claim 1 , further comprising pre-esterifying the fatty acid feedstream prior to introduction of the fatty acid feedstream into the reaction vessel. 
     
     
         14 . The method of  claim 1 , wherein the fatty acid feedstream comprises one or more fatty acids selected from the group consisting of decanoic acid, dodecanoic acid, tetradecanoic acid, hexadecanoic acid, octadecanoic adic, octadecenoic acid, linoleic acid, eicosanoic acid, and isostearic acid. 
     
     
         15 . The method of  claim 1 , wherein the fatty acid feedstream comprises 99% or greater fatty acids. 
     
     
         16 . The method of  claim 1 , wherein the biodiesel comprises from 0 to about 0.20% by weight total glycerin. 
     
     
         17 . The method of  claim 1 , wherein the biodiesel comprises from 0 to about 500 ppm sulfur. 
     
     
         18 . The method of  claim 1 , wherein the biodiesel comprises a water content of less than 0.050% by volume. 
     
     
         19 . The method of  claim 1 , wherein the biodiesel comprises a kinematic viscosity of between 1.9 and 6 min 2 /s. 
     
     
         20 . The method of  claim 1 , wherein the biodiesel meets EN 14214.