ASPECTS OF JET FUEL OXIDATION

A quartz crystal microbalance (QCM)/Parr bomb system with a headspace oxygen sensor is used to measure oxidation and deposition during therm al oxidative stressing of jet fuel. The advantages of the oxygen senso r technique in monitoring fuel oxidation is demonstrated. Simultaneous measurement of deposition using the QCM shows a strong correlation be tween oxidation and deposition in jet fuels. Studies performed over th e temperature range 140 to 180 degrees C show that surface deposition peaks at an intermediate temperature, while bulk deposition increases with temperature. In studies of jet fuel antioxidants, we find that ra pid increases in oxidation rate occur upon consumption of the antioxid ant. The antioxidant appears to be consumed by reaction with alkylpero xy radicals. In studies of metal deactivator (MDA) additives, we find that MDA is consumed during thermal stressing, and this consumption re sults in large increases in the oxidation rate of metal containing fue ls. Mechanisms of MDA consumption are hypothesized.