Submitted to: Journal of the American Oil Chemists' Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/1/2002
Publication Date: 10/10/2002
Citation: LEE, K., FOGLIA, T.A., CHANG, K. PRODUCTION OF ALKYL ESTER AS BIODIESEL FROM FRACTIONATED LARD AND RESTAURANT GREASE. JOURNAL OF THE AMERICAN OIL CHEMISTS' SOCIETY. 2002. V. 79. P. 191-195. Interpretive Summary: Biodiesel is the general term applied to alkyl ester derivatives of fats and oils when they are used as neat diesel fuel or diesel fuel extenders. There is much interest in the usage of this alternative fuel because of its improved emission characteristics over petro-diesel. A major impediment to the widespread usage of this alternative fuel, however, is the higher cost of biodiesel compared to petro-diesel. Since the price of the feedstock represents about 75% of the cost of biodiesel, there is interest in using lower cost feedstocks to produce biodiesel. Lard and restaurant grease command lower prices than other commodity fats and oils; hence, their use as feedstocks for biodiesel production should lower the cost of biodiesel. However, technical challenges must be overcome for producing biodiesel with acceptable fuel properties when using these alternative feedstocks. In this report, we describe the production of biodiesel from fractionated lard and semi-refined greases to provide biodiesel fuels with improved low-temperature properties compared to biodiesel fuels prepared from the unmodified feedstocks. This technology, therefore, has the potential of expanding the production of biodiesel from these non-traditional feedstocks.
Technical Abstract: Methyl or ethyl esters were produced from lard and restaurant grease in lipase- or based-catalyzed reactions. Before esterification, the starting composition of the substrates (lard and restaurant grease) was manipulated by acetone fractionation or by column chromatography using a 1:1 mixture of magnesium silicate and aluminum oxide. Because excess amounts (>1 mole) of methanol deactivated the lipase, each additional mole equivalent of methanol was added sequentially to the reaction mixture after 24 h initial reaction. Using this three-step process a 74% conversion of lard to -methyl esters was obtained. The presence of silica, however improved the conversions in the single-step reactions. For example, at a 1:3 (fractionated lard/methanol) substrate mole ratio, the conversion to esters was only 2.85% after 48 h reaction whereas addition of 10-wt% silica to the reaction mixture increased ester yields to 58%.. Regenerated restaurant grease (FFA removed by column chromatography) also was converted to esters by alkali-catalyzed methanolysis. After 24 h of reaction, 96% conversion to esters was obtained, whereas only a 25% conversion was obtained with the crude grease. The alkyl esters produced in this study could be used as biodiesel fuels with improved low-temperature properties.