Deposit formation of deoxygenated JP-8 fuel with added hydroperoxides

Date of Award

2013

Degree Name

M.S. in Chemical Engineering

Department

Department of Chemical and Materials Engineering

Advisor/Chair

Advisor: Steven Zabarnick

Abstract

The performance of jet fuel is an important consideration as aircraft capabilities continue to improve. In addition to use as a propellant, jet fuel is used as a coolant for major subsystems. One of the consequences of using jet fuel as a coolant in high performance aircraft is the production of carbonaceous deposits that result from the autoxidation of fuel by dissolved oxygen. The deposits cause fouling of critical aircraft components and can lead to catastrophic failure. Autoxidation has been studied for decades, but the chemical mechanism by which deposits form is poorly understood. For this thesis, a single portion of the autoxidation mechanism, hydroperoxide decomposition, was isolated as a way to investigate the pathways that lead to fuel deposition. The carbonaceous deposits produced by JP-8 jet fuel were measured for a flowing, single-phase reaction system. Hydroperoxides were shown to cause significant deposit production in jet fuel, even in the absence of autoxidation. Hydroperoxide decomposition was isolated and deposition was also measured for fuel with selected chemical species added. Copper was studied for its effect on deposit production because of its known effect on catalyzing hydroperoxide decomposition. Acid was selected for study due to its known effect on synergistically catalyzing hydroperoxide decomposition when present with copper. Both species were shown to promote deposit production, individually and together, although not synergistically. Metal deactivator additive (MDA) was shown to have an extraordinary effect on decreasing deposition. Two tests were replicated using a fuel sample distinct from other tests performed for this thesis; the results indicate the effect of hydroperoxides and copper on deposition are not limited to a specific fuel sample. Several oxygenated fuels were also studied, in which hydroperoxide decomposition was not isolated. These fuels were shown to produce less surface deposits, but significantly more bulk deposits, than cases in which hydroperoxide decomposition was isolated. Several possible explanations are discussed. Copper was additionally shown to promote deposition in the case with oxygen and added hydroperoxides

Keywords

Jet planes Fuel Deoxidizing, Peroxides Decay, Distillation, Destructive, Precipitation (Chemistry), Chemical engineering; autoxidation; jet fuel; hydroperoxide decomposition; deposition; hydroperoxides; copper

Rights Statement

Copyright © 2013, author

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