Synthesis and characterisation of biodiesel from Nigerian physic nut,castor bean,dika nut and sandbox seed oils

Biodiesel fuels were synthesised from Nigerian physic nut seed (Jatropha curcas), castor bean seed (Ricinus communis), dika nut (Irvingia gabonensis) and sandbox seed (Hura crepitans) oil. The direct base-catalysed transestetification process was employed in the biodiesel production using methanol and sodium hydroxide (NaOH) as alcohol and catalyst, respectively. The transesterification process involved 500 ml of J. curcas, castor bean seed, dika nut and sandbox seed oils, 100 ml of methanol and 1.0% of NaOH by weight for each oil. The process was carried out at different reaction temperatures in order to examine the effect of temperature on biodiesel yield of the oils. An average maximum biodiesel yield of 89.00% at 50 °C, 61.50% at 45 °C, 74.33% at 50 °C and 88.50% at 55 °C were obtained for Jatropha, castor, dika nut and sandbox oils, respectively. The calorific values of diesel decreased from 42.7 to 42.475, 41.48, 42.330 and 42.13 MJ/kg with a blend of 10% of physic nut, castor bean, dika nut and sandbox seed biodiesel, respectively. The calorific values of the produced biodiesel from physic nut, castor bean, dika nut and sandbox seed oils are 40.45, 30.50, 39.00 and 37.00 MJ/kg, respectively. The cetane number, kinematic viscosity at 40 °C and pour point of the produced biodiesel are 59.4, 4.20 mm²/s and?1°C for physic nut biodiesel; 50, 10.75 mm²/s and?45°C for castor biodiesel; 52, 3.20 mm²/s and?6°C for dika nut biodiesel and 50, 4.20 mm²/s and 6 °C for sandbox seed biodiesel, respectively. The results showed that the addition of biodiesel to diesel generally increases the density, kinematic viscosity, flash point and pour point but, on the other hand, reduces the calorific value of the produced blend.