Esters of ricebran oil with short chain alcohols as alternative fuel for diesel engines

The potential of ricebran oil as a feedstock for the production of a fuel for diesel engines alternative to regular diesel fuel has been assessed. Esterification rate of crude ricebran oil with methyl alcohol was studied using different volumetric ratios of alcohol to oil, different catalyst loads and catalyst types. Catalysts used were sulfuric acid at a concentration of 2% of the oil/alcohol mixture in addition to hydrochloric acid and Amberlite IR-120 cation exchange resin at the same molar concentration of H+ as in case of sulfuric acid. The reaction was fastest using sulfuric acid which has been then used to prepare esters of ricebran oil with methyl, ethyl, propyl and butyl alcohols. The four products have been evaluated as a fuel for diesel engines according to their fuel properties compared to regular diesel fuel. These properties include the calorific value, flash point, viscosity, pour point, cetane number, sulfur content and ASTM distillation characteristics. The results have shown that the methyl as well as the ethyl esters have the closest properties to those of regular diesel fuel. Diesel engine performance using blends of regular diesel fuel with methyl and ethyl esters of ricebran oil have been tested and compared to that using regular diesel fuel. The results have shown that the engine performance using a blend of 50% regular diesel fuel and 50% methyl esters of ricebran oil is better than that using regular diesel fuel. The brake thermal efficiency at full load was 30.2% using the fuel blend compared to 27.5% in case of regular fuel.