Comparative analysis of the atomization characteristics of fifteen biodiesel fuel types

Engine results using biofuels have varied considerably in the reported lite rature. This article addresses two potential sources of this variation, ato mization differences and impurities due to lack of quality control during p roduction. Atomization is the first process encountered during the combusti on of fuels in a compression ignition engine and is largely determined by t he fuel's viscosity and surface tension. Previous work using five experimen tally produced methyl ester biodiesel fuels showed that the viscosity and s urface tension could be predicted from their fatty acid ester composition, and the atomization characteristics in turn could be predicted from their v iscosity and surface tension. This article utilizes the results of that wor k to give a quantitative comparison of the atomization characteristics of f ifteen biodiesel fuel types using the fuel's viscosity and surface tension, predicted directly from the fatty acid composition of the fuels. Except fo r coconut and rapeseed biodiesel fuels, all of the rest of the 15 biodiesel fuels had similar atomization characteristics. Since the most likely conta minant in the fuel from the processing was residual glycerides, their effec t on viscosity and surface tension was studied experimentally and their eff ect on the atomization characteristics was computed.