Abstract:
Fossil fuel, the major sources of world energy needs is beset with the problems of rapid depletion and negative
environmental impact. Among the various alternatives investigated for diesel replacement, biodiesel has
emerged the most suitable. This research work focused on response surface optimization and engine emission
analysis of rubber seed oil (RSO) biodiesel. The oil from rubber seed was solvent extracted and characterized
based on American Society for Testing and Materials (ASTM) method. The fatty acid profile and the oil
functional groups were determined using gas chromatography mass spectroscopy and Fourier transform
infrared spectroscopy respectively. The effect of process parameters on the yield of rubber seed oil biodiesel
or rubber seed oil fatty acid methyl ester (RSOFAME) was investigated using one factor at a time method.
The process parameters and RSOFAME yield were optimized using response surface methodology (RSM).
The engine emission analysis of RSOFAME, diesel and their blends was carried out using Perkin 4:108 diesel
engine. The oil content of RSO was determined as 40.02%. The RSO physiochemical properties were
determined as, acid value, free fatty acid, saponification value, iodine value, peroxide value, kinematic
viscosity, fire point, flash point, cloud point, pour point, refractive index specific gravity, moisture content,
and density, 28.72mgKOHg-1, 14.36%, 185.66mgKOHg-1 120.4gI2100g-1, 14.62meqkg-1, 38.5mm2s-1 @
400C, 1800C, 1320C, 60C, 20C 1.428, 0.92, 7%, 920Kgm-3, respectively. The RSOFAME fuel properties
were determined as, density, kinematic viscosity, cetane number, flash point, cloud point, water content, acid
value, calorific value, iodine value, and pour point, 880kgm-3 4.25mm2s-1 58.2, 1640C, 40C. 0.44%,
0.32mgKOHg-1, 38.5MJkg-1,72gI2100g-1, 20C, respectively. The optimum conditions suggested by the
result analysis for maximum RSOFAME yield of 93% within the ranges studied were: methanol to oil molar
ratio 7:1, catalyst concentration 0.75%wt, reaction temperature 500C, reaction time 45 minutes. Actual
experiment based on the optimum conditions produced 91.79% yield of RSOFAME. The engine emission
analysis revealed that carbon monoxide (CO), hydrocarbon (HC) and nitrogen oxides (NOx) emission
increased with increase in engine load. At a specific engine load, CO and HC emission decreased with
increase in biodiesel fraction while NOx increased with increase of biodiesel fraction |
