Effect of Castor Oil, Methyl and Ethyl Esters as Lubricity Enhancer for Low Lubricity Diesel Fuel (LLDF)

The major objective of this study was to analyze the effectiveness of Indian wild castor oil and methyl/ethyl ester as an additive to enhance the lubricity of low lubricity diesel fuel. The methyl and ethyl ester of castor oil were formulated by transesterification reaction using homogeneous acid-base catalyst. The conformity of the ester was carried out by gas chromatograph (GC) and proton nuclear magnetic resonance (H-1 NMR) spectroscopy. The lubricity, wear scar diameter (wsd), and film thickness (%) of the oil and its esters were tested alone and as an additive in low lubricity diesel fuel and compared. The lubricity of the test samples were analyzed by high-frequency reciprocating rig (HERR). The test results shows that even less than 1% of castor oil, methyl and ethyl ester are enough to regain the lubricity of the low lubricity diesel fuel. In the study, it was observed that the ethyl ester has comparatively better lubrication than their methyl counterpart and fresh oil. An additive dose of even 0.2% is enough to bring the wsd down to below the maximum allowable limit of 450 pm. The wsd of low lubricity diesel fuel (LLDF) was 654 pm. The wsd of LLDF was appreciably reduced with the addition of 1% of castor oil (CO), castor oil methyl ester (CM), and castor oil ethyl ester (CE). The percentage reduction in the wsd was observed to be 70.03%, 70.48%, and 75.69%, respectively, with the addition of 1% of additive.