Production, characterization and evaluation of castor oil biodiesel as alternative fuel for diesel engines

Abstract

In this study, the use of castor oil methyl ester as possible alternative fuel for diesel engines was investigated. The oil was extracted in a soxhlet extractor using normal hexane as solvent. To overcome the high kinematic viscosity of the neat oil, a high molar ratio of 6 : 1 was used to produce the methyl ester. The viscosity of the ester was high and further reduced by blending with diesel fuel to reduce it to within the American Society for Testing and Materials (ASTM) D6751-02 limits for biodiesel. The biodiesel was characterized and tested in a single cylinder diesel engine. The results obtained gave properties, torque outputs and specific fuel consumption that are close to those of diesel fuel thus confirming that it can be used as alternative fuel for diesel engines. Chromatography analysis of the methyl ester shows that it contains 90% ricinoleic acid which is a monounsaturated, 18-carbon fatty acid with a high polarity hydroxyl functional group at C12 and ester linkages that makes the fuel unsaturated and with a wide range of industrial applications.