Production, Characterisation and Fatty Acid Composition of Jatropha curcas Biodiesel as a Viable Alternative to Conventional Diesel Fuel in Nigeria

Abstract

Ethyl ester biodiesel has been produced from a non-edible Jatropha curcas oil. Oil was extracted from the plant seed using n-hexane at 60°C and pretreated by alkaline refining process to reduce the free fatty acid level to less than 1%. Base-catalysed transesterification reaction with absolute ethanol using potassium hydroxide catalyst was adopted for the conversion. Various physicochemical properties of the refined Jatropha curcas oil were investigated. The ethyl ester biodiesel produced was characterised for its fuel properties such as specific gravity at 15°C, flash point, pour point, kinematic viscosity, cetane number, iodine value and higher heating value using American Society for Testing and Materials Standard Methods. The crude and refined Jatropha curcas oil yields were 58.16% and 52.5%. The physicochemical analysis revealed FFA, saponification value and peroxide value of refined Jatropha curcas oil to be 0.58 mg KOH/g, 159.9 and 1.92 m E/kg respectively. The fatty acid composition obtained from gas chromatography (GC) revealed that the oil contained 44.85% oleic acid as the dominant fatty acid, while Margaric 0.01% and Behenic 0.02% the least. The biodiesel yield was 57.6%, and its measured fuel properties conformed with ASTM 6751 and EN 14214 standards.