Author(s): Umeuzuegbu JC

Abstract: The rapid depletion of fossil fuel and its environmental impact has resulted in the search for alternative energy sources. Among the various alternatives investigated for diesel replacement, biodiesel has emerged the most suitable alternative to diesel fuel. This research work focused on optimization and kinetic modeling of sesame seed oil (SSO) fatty acid methyl ester (SSSOFAME) or biodiesel. The oil content of the seed was n-hexane solvent extracted using soxhlet extractor and the physiochemical properties of the oil extracted characterized based on American Society for Testing and Materials (ASTM) methods. The fatty acid profile was determined using gas chromatography mass spectrometry while the functional group of the oil was analyzed using Fourier transform infrared spectroscopy. Optimization of SSOFAME was effected using classical approach. The transesterification parameters were optimized using one factor at a time method. Kinetic experiment were carrid out in batches at temperatures of 45 0C, 55 0C and 65 0C and the kinetic data from GC-MS was fitted into the integral rate equation of zero, first and second order reactions respectively to obtain the kinetic parameters. The fuel properties of the SSOFAME produced was determined based on ASTM standards. The physiochemical properties of SSO were experimentally determined as density 890 kg/m3, saponification value 191.4 mgKOH/g, iodine value 86.5 gI2/ 100 g, peroxide value 2.0 mEq/kg, kinematic viscosity 32.5 mm2/s, fire point 201 0C, flash point 183 0C, cloud point 2.5 0C, pour point 0.5 0C, refractive index 1.465, specific gravity 0.890, moisture content 0.5%, acid value 1.98 mgKOH/g, free fatty acid 0.99%, and calorific value 28.5 MJ/kg respectively. The fatty acid profile of SSO shows the constituent to be mainly oleic, linoleic, palmitic and stearic acid. The optimum process parameters obtained from this work are methanol to oil molar ratio 8: I, catalyst concentration 1% wt., reaction temperature 55 0C, reaction time 60minutes, and agitation speed 300 rpm while the optimum biodiesel yield is 90%. Kinetic modeling shows transesterification of SSO to be second order reaction with activation energy of 28.55 KJ/mol. The fuel properties of the produced SSOFAME are density 850 kgm-3, kinematic viscosity 4.72 mm2/s, cetane number 59, flash point 170 0C, cloud point 2 0C, water and sediments 0.02%, acid value 0.25 mgKOH/g, calorific value 38.5MJ/kg, iodine value 78.2 gI2/100g, pour point 0.5 0C, specific gravity 0.85, free fatty acid 0.13%, and refractive index 1.467.

Pages: 01-12 | Views: 851 | Downloads: 431

Download Full Article: Click Here