Properties of soapnut (Sapindus mukorossi) oil biodiesel and its blends with diesel

The feasibility of biodiesel production from soapnut (Sapindus mukorossi) oil was investigated with respect to the fuel properties and its blending properties with diesel. Soapnut oil methyl esters (SNME) had satisfactory fuel properties, and the predominant components were methyl oleate at 55.2 wt.% and methyl eicosenoate at 23.9 wt.%. The SNME had the cetane number of 58, cold filter plugging point of 6 °C, flash point of 177 °C, iodine value of 83.6 g I2/100 g, and kinematic viscosity of 4.88 mm2/s at 40 °C. In addition, the oxidation stability of the SNME satisfied the requirements of the biodiesel specifications. Furthermore, the SNME was blended with diesel at various volumetric percentages and evaluated for fuel properties in comparison with the relevant specifications. The linear correlations were established to describe the variations of the properties of the SNME-diesel blends with the volumetric percentage of the SNME.