Evaluation of JFTOT Tube Deposits by Carbon Burnoff

The Jet Fuel Thermal Oxidation Tester (JFTOT) is universally used to measure high temperature stability of aviation turbine fuels, which are pass or fail rated according to the amount of deposit formed on the heater tube, assessed by an optical reflectance method. A new quantitative tube rating method has been developed, in which the weight of deposit is determined by carbon burnoff. When applied to a series of test fuels, reasonable repeatability of results was obtained; it was also found that the magnitude of deposits at a given temperature varied with the type of fuel under test.