Fuel Lubricity Assessment of Fossil and Synthetic Paraffinic Kerosene to Be Used in Reciprocating Engines

Abstract

Society currently faces the greatest challenge of finding solutions to decarbonize transportation while achieving net zero emissions. The interest in new renewable fuels provides an opportunity to further investigate the single fuel concept for various transportation modes, which has been explored since the 1990s. The feasibility of employing aircraft-based fuels (synthetic paraffinic kerosene) in compression ignition engines to exploit their wide range of applications is studied. The high cetane number and heating value of synthetic paraffinic kerosene encourage its use in compression ignition engines, while its deficient lubricity properties should be improved. This work proposes the incorporation of a renewable fuel (biodiesel) as an additive into a fossil and synthetic paraffinic kerosene (SPK) to enhance their lubricating properties. Tests were performed using a high-frequency reciprocating rig, equipment required in diesel fuel standards. In particular, the effects of biodiesel content added to the kerosene fuels on the mean wear scar diameter, type of wear, coefficient of friction, and lubricating film are investigated using a high-frequency reciprocating rig. The addition of 2% biodiesel (in volume) significantly reduced the MWSD, enabling it to fulfill the lubricity limit specified in the EN 590 standard. This study provides new knowledge by identifying that the addition of biodiesel changes the wear mechanisms associated with the use of kerosene-based fuels, characterized by the presence of red-brown localized pits and microcraters. This work provides experimental evidence demonstrating, on one hand, the similar behavior of SPK in comparison with Jet A1 and, on the other hand, that biodiesel is an effective fuel component to be added into paraffinic kerosene fuels to enhance lubricity even more than with lube oil addition for use in diesel engines.