Production, Characterization and Glycerine Analysis of Soybean Oil and Its Biodiesel

Abstract

Aims: To examine the viability of Soybean Oil as a feedstock for Biodiesel production by carrying out its characterization and examining its thermodynamic properties to see if they are within ASTM limits. Study Design: Place and Duration of Study-The production was conducted in the Department of Mechanical Engineering of the University while the characterization of the Biodiesel was conducted at the Postgraduate Research Laboratory. Samples of Glycine ma (L.) merril were obtained from a local market in the Akure town of Ondo State, Nigeria in October of 2014.  Methodology: Oil Extraction-The oil was extracted using soxhlet extractor, but before extraction the soybeans were crushed in a blender to increase the area exposed to the petroleum ether solvent. The extraction flask was dried in an oven at 105°C and the weight was measured after cooling. 2.5 g of soybean was poured into the flask and leached for 5 hours after which extraction flask was removed from the mantle heater after all the petroleum ether was removed with rotary evaporator and the oil was oven dried at 105°C for one hour to remove any water present. The flask was finally cooled to room temperature in a desiccators and the weight of the flask and dried oil was again measured. Transesterification and Glycerine Analysis Process: 50 mg of the extracted oil was esterified 5 times at 95°C with 3.5 ml of the 0.5 M KOH of dried methanol. The mixture was neutralized using 0.7M HCL. 3 ml of 14% boron triflouride in methanol was added and the mixture was heated for 5 minutes at 90°C to achieve completed methylation process. The fatty acid methyl esters were thrice extracted from the mixture with redistilled methanol. The content was concentrated to 1mL for gas chromatography analysis and 1 µL was injected into the port of the Gas Chromatograph analyzer. Results: most of the pertinent parameters for the determination of validity were found to be within ASTM limits, namely: Flash Point (135°c / 130°c min); Kinematic Viscosity (4.80 / between 1.9 - 6); Cetane number (55 / 47 min); Copper Strip Corrosion (1 / 3 max); %Carbon Residue (0.12 / 0.050); %Sulphated Ash (0.044 / 0.020). Conclusion: Given the obviously good numbers associated with the study relative to ASTM standards, Soybean is a viable source of Biodiesel. However, further study could explore the use of Soybean chaff and other waste matter obtainable from it rather than the entire crop.