Biodiesel Production by Pyrolysis from Waste Animal Fats

Abstract

The biodiesel has attracted attention as an alternative fossil fuel. Generally, the biodiesel is fatty acid methyl esters obtained from triglycerides which are the principal ingredients of oils and fats. The plantation vegetables of biodiesel raw materials are grown in Europe and America. On the other hand, it is necessary to use waste cooking oils in Japan where the cultivated acreage is narrow. The flee fatty acids are included in waste cooking oils decrease the biodiesel yield. Moreover, the long chain saturated compounds of animal fats in waste cooking oils lower the low temperature property of the obtained biodiesel. The pyrolysis of waste cooking oils was examined in order to apply to the manufacturing method of the biodiesel. As the results, it was cleared that the triglyceride generates the fatty acids by the ester bond decomposition at 360-390°C. Next, the fatty acids decompose and the short chain hydrocarbon is generated. Moreover, the hydrocarbon of the light oil fraction is obtained by the decarboxylation of the hydrocarbon at 420°C. At this time, the yield and the selectivity of the light oil fraction can be improved when the activated carbon supported palladium is added as a catalyst. The obtained light oil fractions had a good low temperature property.