Abstract:
The main objective of this project was to study biodiesel production from two local nonedible plant feedstocks namely Jatropha curcas and Croton megalocarpus. The oil from the above plant seeds were mechanically extracted using a screw pressing machine and the oil yield determined. Preliminary test were done on the neat oil to ascertain their quality, these included; viscosity, density, acid value, iodine and calorific value. The oils were then converted into biodiesel through trans-esterification process using methanol and potassium hydroxide as a catalyst. The factors governing the trans-esterification process investigated included; reaction time, amount of base catalyst (potassium hydroxide) per liter of oil, amount of methanol per liter of oil and reaction temperature, , , , Biodiesel yield of 87.5 % CNIE and 71.3 % JME were obtained at methanol/oil ratio of 5:1, temperatures of 60°C, reaction time of one hour while KOHlliter oil was 0.75 wt% croton oil and 1.5 wi% jatropha oil respectively. Blends consisting of Jatropha curcas methyl esters (JME) and Croton megalocarpus methyl esters (CNIE) were also prepared and tested in the proportions; 25%JilIE and 75%C1vIE, 50%JME and 50%C1vIE and 75% JME and 25%CNfE. The above mixtures were further separately blended with commercial diesel to obtain B5, B10 and B20 blends. The individual esters were separately blended with grade 2 diesel (DF2) to obtain B5, B10 and B20. Both esters and their blends with DF2 were characterized with respect to specific gravity, kinematic viscosity, iodine value, acid value and calorific value. The kinematic viscosities of all blends of the esters were lower than those of J1vIE(B100) and ClI1E(BlOO) at all temperatures. Blending the above fuel esters with commercial DF2 lowered the specific gravity and kinematic viscosity significantly. The acid values for all the neat fuel esters and their blends were. found to be within the allowed maximum limit of 0.8mgKOHlg. The calorific values decreased with increase in percentage ofbiodiesel in the blends. The iodine values for both the SVO, neat fuel esters and their blends were within the allowed maximum limits of 115ghll00g oil and 120ghll OOgoil except for SVO from Croton megalocarpus which gave a high iodine value of 133ghllOOg oil. The fatty acid methyl ester composition from CNIE determined usmg gas chromatography showed it to contain primarily the three fatty acid methy esters of methyl palmitate, methyl stearate and methyl oleate. The engine performance tests of neat esters and their blends as investigated included; brake specific fuel consumption, thermal efficiency, brake horsepower and exhaust temperatures. The results obtained were comparable to those of commercial DF2.