Re-addition of antioxidant to aged MEROX and hydroprocessed jet fuels

Long term storage of aviation turbine fuels often requires the use of antioxidants with many military fuel specifications mandating its addition for hydroprocessed fuels. This work examines the influence of antioxidants on aged and freshly refined aviation turbine fuels of various types, some containing antioxidant at manufacture and others not. The rate of antioxidant depletion is reported along with the re-stabilised fuel's oxidation induction periods. It was found that some fuel types do not benefit from re-addition of antioxidant and no improvement was observed for inhibition of hydroperoxide formation in aged fuels, however oxidation induction times were improved for re-addition of antioxidant for all fuels examined. A simple method for assessing the degree of hydroprocessing of an unknown fuel was also examined with limited success.