A. C. Nixon
Published: 1966
Total Pages: 307
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Investigation of the feasibility of utilizing hydrocarbons as heat-sink fuels for hypersonic aircraft has continued. Both thermal and catalytic endothermic reactions have been considered, at temperatures up to 1400 F, pressures to 1000 psi, liquid hourly space velocities up to 260 and 150, respectively. Mono- and dicyclic naphthenes appear to be the most promising feeds to date. Utilizing dehydrogenation to the corresponding aromatics over a platinum on alumina catalyst, reaction heat sinks of about 1000 Btu/lb of feed should be achievable with the lower members of the series, such as cyclohexane, methylcyclohexane, dicyclohexyl, and decalin. Laboratory studies have been made on the dehydrogenation of a wide variety of naphthenes over Pt/Al2O3 catalysts to determine approximate reaction kinetics and selectivities. Rates of reaction generally increase with alkyl substitution. Activation energies show variable behavior. Selectivities for the corresponding aromatics are high. Some problems with catalyst life and consecutive reactions have been encountered; some solutions have been found.