(201f) Impact of Deep Hydrogenation on Jet Fuel Oxidation and Deposition

Thermal oxidative stability is the main character for jet fuel serving as coolant of supersonic or hypersonic aircrafts. This study investigated the effect of hydrogenation degree on jet fuel (RP-3) oxidation and deposition. The deep hydrogenation of RP-3 were achieved by commercial noble catalyst in an autoclave with 4 MPa hydrogen at 190 °C, and the reaction time was controlled to acquire fuels with different hydrogenation degree. The aromatic content of the most hydrogenated fuel is reduced from 12.6% to 0.5%, and the total sulfur content is lowed to below 3 ppm. Accordingly, the density of hydrogenated fuels slightly decreases but the net heat of combustion slightly increases due to the saturation of aromatics. The oxidation reactivity and deposition tendency of hydrogenated fuels were further conducted by pressure differential scanning calorimetry (PDSC) and jet fuel thermal oxidation tester (JFTOT), respectively. The decrease of onset oxidation temperature and induction period of hydrogenated fuels highlight a significant effect of aromatic content on jet fuel oxidation. However, hydrogenated fuels exhibit lower deposition propensity upon thermal oxidative stress. These results indicate that deep hydrogenation can effectively improve jet fuel thermal oxidative stability (fewer deposits) but reduce the anti-oxidation effect of jet fuel. Oxidative products of aromatics and inherent heteroatomic compounds detected by comprehensive two-dimensional gas chromatography are responsible for the confliction impact of deep hydrogenation on oxidation and deposition.