Non-Catalytic Thermal Reforming of JP-8 in a Distributed Reactor
Scenna, Richard Michael
Gupta, Ashwani K
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This investigation focuses on developing a fundamental understanding of the thermochemical behavior of the application of the advanced combustion technique of Colorless Distributed Combustion to the thermal partial oxidation of a hydrocarbon fuel. Distributed Reaction Regime is achieved through internal entrainment and dilution to enlarge the “reaction zone” to encompass the entire reactor. The expanded reaction zone results in a uniform thermal field and product distribution. This in turn increases the local availability of water and carbon dioxide, which promotes steam and dry reforming reactions to a lesser extent, enhancing syngas yields. It was observed that the more distributed conditions (greater entrainment) yielded higher reformate quality. In the high temperature reactor, this resulted in higher hydrogen yields. In lower temperature reactor, the more distributed conditions shifted the hydrocarbon carbon distribution to favor ethylene and methane over acetylene. Middle distillate fuels are very challenging to reform. The high sulfur, aromatic, and carbon content inherent in these fuels will often deactivate conventional reforming catalysts. To compensate for the lack of catalyst, non-catalytic reformers employ high reactor temperatures, but this promotes soot formation and reduces reforming efficiency. Reforming under Distributed Reaction Regime avoids the issues associated with catalysts, while avoiding the issues associated with operating at higher reactor temperatures. The middle distillate fuel, Jet Propellant 8 (JP-8) is of particular interest to the military for small fuel cell applications and was determined to be a good representative for middle distillate fuels. This novel approach to reforming is undocumented in literature for a non-catalytic approach. This investigation studies the thermochemical behavior of a middle distillate fuel under reforming conditions. Chemical time and length scales are controlled through variations in injection temperature, oxidizer concentration, and steam addition. Two reactors were developed to study two different temperature ranges (700-800°C and 900-1100°C). These reactors will allow systematic means to enhance favorable hydrogen and carbon monoxide yields. Through the course of investigation it was observed that conditions that promoted a more distributed reactor were found to yield higher quality reformate. On multiple instances, the improvement to reforming efficiencies was greater than could be accounted for by varying the reactants alone. Reforming efficiency was demonstrated as high as 80%, rivaling that of catalytic reforming (85%). The Distributed Reaction Regime suppressed soot formation from occurring within reactor. No soot formation within the reactor was observed while operating within the Distributed Reaction Regime.