Synthesis And Characterization Of Biofuels From Various Nigerian Crops For Internal Combustion Engines

ABSTRACT

Bio-fuels (Biodiesel and Bio-ethanol fuels) are synthesized from various Nigerian crops (palm(Elaeis Guineensis) wine, raffia(Raffia Vinefera) trunk, sugar cane(Saccharum L), physic nut seed (Jatropha Curcas), castor bean seed(Ricinus Communis), sandbox seed (Hura Crepitans) and African bush mango nut (Dika Nut) (Irvingia Gabonensis)) to serve as alternative fuels for internal combustion engines. The direct base-catalyzed trans-esterification process is employed in the biodiesel production using methanol and a homogeneous base (sodium hydroxide) as alcohol and catalyst respectively. Bioethanol was obtained through fermentation and distillation from sugar cane, raffia trunks and palm wine and then purified. Physical properties of the bio-ethanol and various petrol bio-ethanol blends such as vapour pressure, octane number, flash point, heating values, auto ignition temperature and density were evaluated. The neat biodiesel and bio-ethanol fuels and its blends are characterized using the American Society for Testing and Materials (ASTM) methods. The evaluated properties for the biodiesel fuels are density, kinematic viscosity, pour point, flash point, cloud point, heating value and cetane number. These properties are compared in relation to the international standards for petrol and diesel engine fuels. The octane number increased from 86 at E10 to 105 at E90. The calorific value decreased from 44.22MJ/Kg at E10 to 30.10MJ/Kg at E90. The optimal petrol-bioethanol blend of E20 was recommended for Nigerian vehicles running on spark ignition engines. Biodiesel yields of 67%, 68.5%, 69.32% and 56% were obtained from jatropha, dika, castor and sandbox oils respectively. Cetane values of 59.4, 52, 50 and 50 and kinematic viscosities of 4.2mm2 /s, 3.2mm2 /s, 10.75mm2 /s and 4.2mm2 /s were obtained for jatropha, dika oil, castor and sandbox biodiesel respectively. The results of the characterization showed that the produced fuels are alternative fuels that can be used on modern diesel and petrol engines with little or no engine modifications.