| Abstract
| - Future high-speed aircraft will be challenged to meet their onboard cooling requirements,because of weight limitations and higher heating loads. Therefore, the fuel will be required toserve as both propellant and coolant, and, thus, the fuel will need to be thermally stable. Anadvanced thermally stable jet-fuel formulation, called “JP-900”, has been under development forsuch applications. Six formulations of potential JP-900 basestocks were tested in a flow reactorto assess their thermal stability and resultant deposit morphology. Of the six fuels that weretested, three fuels consisted largely of hydroaromatic and aromatic compounds, and the otherthree fuels consisted mainly of cyclic compounds. The fuels were made from refined chemical oil(RCO), a product of coke manufacture, light cycle oil (LCO), a petroleum product, or blends thereof,and were hydrotreated to different extents. All six fuels showed marked improvements in stabilitywhen compared to the conventional military jet fuel JP-8. The fuels that consisted largely ofhydroaromatic compounds were stable at high temperatures but produced large amounts ofdeposits in the autoxidative regime, whereas the fuels that consisted of cycloalkanes were morestable in both the autoxidative and pyrolytic regimes than their less-saturated counterparts.Basestocks derived from RCO were more stable in the pyrolytic regime than those derived fromLCO. This observation was attributed to their differences in gross fuel composition. Removal ofdissolved oxygen via nitrogen sparging increased both the autoxidative and pyrolytic stability ofall six fuels. There were also morphological differences in the high-temperature deposits formedby the sparged and nonsparged fuels, which indicated differences in the deposition mechanismwhen dissolved oxygen was present in the starting fuel.
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