Journal Article

Emissions Characteristics of Biodiesel Blends From Yellow Oleander (Thevetia peruviana) Seed Oil

Abstract

The emissions characteristics of Yellow Oleander seed oil biodiesel and its blends with conventional diesel were evaluated. This was done by running a stationary single-cylinder, 4-stroke air cooled diesel engine at varied torques of 2 Nm, 4 Nm, 6 Nm, 8 Nm, and 10 Nm on, first 100% diesel (D100), then 100% biodiesel (B100), and, subsequently, on blends of the biodiesel with the diesel in the proportion by volume of 30% biodiesel (B30); 20% biodiesel (B20); and 10% biodiesel (B10). The emissions of unburnt Hydrocarbons, HC; Carbon IV oxide, CO2; Carbon II oxide, CO; and oxides of Nitrogen, NOx were measured at these engine load torques. Results showed that, over the entire engine load, the B100 had the lowest mean emission of unburnt hydrocarbon at 11.6 ppm – about 18% lower than that emitted using D100 which was 14.2 ppm; B10 had mean emission of HC of 14.2 ppm – about 3% higher than that of D100; and B30 and B20 also had lower HC emissions than D100 at 13.6 ppm and 12.6 ppm, respectively – with the later having the lowest HC emission of 8 ppm at a torque load of 10 Nm – while B10 had near identical mean emission with D100 at 14.6 ppm. B100 also had the lowest mean emission of NOx at 222.6 ppm (about 14% lower than that of D100 at 258 ppm), whereas all the other blends had NOx emissions higher than that of D100 (B30: 261 ppm; B20: 273.4 ppm; and B10: 262.6 ppm). Again, B100 had the lowest mean emission of CO of about 0.01% – representing about two times lower than that of the D100 at 0.02%; CO emissions for B30 and B10 were both 0.018% each – about 10% lower than that of D100 – while that of B20 was 0.022% – 10% higher than that of D100. As for the CO2 emissions, the B100 again had the least mean emission at 3.53% – representing about 3% lower than that of the D100 at 3.65%; B30, B20 and B10 all had CO2 emissions higher than that of D100 at 3.66%, 3.70% and 3.70%, respectively. The study concluded that, with only slight differences in the emission characteristics between the D100 and the blends, particularly for unburnt hydrocarbons, the blends of Yellow Oleander seed oil biodiesel with conventional diesel could be used as partial replacement for diesel fuel in Compression Ignition Engines.

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