Abstract:
Biodiesel is a renewable alternate fuel that could partially/fully replace or reduce the use of petroleum diesel fuel. This research project evaluates the viability of coconut oil for biodiesel production and the effect of varied oil-to-ethanol ratios on its transesterification reaction rate with ethanol. Thus, the moisture content of the coconut kernel was determined and coconut oil was extracted from coconut copra using cold extraction. The percentage moisture content of the kernel and the yield of the coconut oil extracted were 14.99% and 44.13% respectively. The physicochemical properties of the coconut oil were determined and the result revealed that the oil is pale yellow, with a specific gravity of 0.88, viscosity of 35.04 mm2/s at 40oC, flash point of 220oC, cloud point of 24oC, pour point of 23oC, volatile matter of 99.72%, refractive index of 1.46, heat of combustion of 35.60 MJ/kg, acid value of 2.24 mgKOH/g, saponification value of 273.38 mgKOH/g, peroxide value of 3.02 meq/kg, iodine value of 9.11 mI2/g and free fatty acid content of 5.64%. The transesterification of the coconut oil (50ml) with ethanol (150 ml) using sodium hydroxide (0.1g) as catalyst gave 93.90% yield of ethyl ester. The physicochemical properties of the ethyl ester produced were also determined and the result obtained were as follows: colour (colourless), specific gravity (0.86), viscosity (6.00mm2/s at 40oC), cetane number (71), flash point (132oC), cloud point (-5oC), pour point (-10oC), ash content (0.02%), refractive index (1.43), conductivity (0.00 μS/cm), heat of combustion (36.786 MJ/kg), acid value (0.25 mgKOH/g), saponification value (218.076 mgKOH/g), peroxide value (0.15 meq/kg) and iodine value (1.91 mI2/g). The transesterification rate constant at varied oil to ethanol ratio of 1:6, 1:3, 1:2, 1:1.5 and 1:1 were 0.4150, 0.3616, 0.2135, 0.1833 and 0.1006 respectively. The result showed that as the oil to ethanol ratios increased from 1:1 to 1:6, the reaction rate constant increased with the highest reaction rate constant of 0.4150 at 1:6 oil to ethanol ratio.
