Pyrolysis And Coking Of Endothermic Hydrocarbon Fuels Under Supercritical Condition

Endothermic hydrocarbon fuel (EHF), as a kind of flammable coolant, can serve as both coolant and propellant for hypersonic aircraft. This work mainly focuses on the studies of the pyrolysis and coking of several kinds of model fuels, which may provide important information for the modification and application of endothermic hydrocarbon fuel.The densities and viscosities were determined over the whole composition range for high-density fuel JP-10(exo-tetrahydrodicyclopentadiene) with n-butanol and n-pentanol respectively. The viscosity deviations, density deviations and the excess molar volumes for the binary systems were calculated from the experimental data, the thermodynamic properties derived from these data were also discussed. Thermal crackings of the binary systems were studied on a batch reactor under3.0MPa used dynamic method. According to the experimental results of the pyrolysis, it was found that the addition of n-alkanol inhibited the decomposition of JP-10and reduced the coking at the same time.The thermal decomposition of the alkanes:n-octane, n-nonane, n-decane, n-undecane, n-dodecane and n-tridecane were studied at different temperatures from575to700℃and the pressure range from0.1to5.0MPa. The effects of reaction temperature, pressure and residence time on the pyrolysis of these samples were discussed. The gaseous products for thermal cracking of alkanes mainly contain methane, ethane, ethene, propane, propene, butane and butene, and the liquid components include alkanes, olefins, cyclanes, benzenes, polycyclic aromatic hydrocarbons and so on. Granular cokes or filamentous cokes were found to be the main components for the free cokes obtained at different reaction conditions. In the present work, the cracking process of n-undecane as an example was analyzed in detail, according to the analysis results, a probable mechanism for decomposition and coking was proposed.JP-10was chosen as a sample of cyclanes, and n-undecane as the representative of chain alkanes. Thermal cracking of the blended fuels of JP-10/n-undecane with different H/C proportion were studied at650℃and3.0MPa. The conversion, yield of gaseous products and the gas-liquid-solid products distribution for the pyrolysis of these blended fuels were discussed. The decomposition conversions of both JP-10and n-undecane in mixtures were affected by the other component. The experimental values of the yield of gaseous products were lower than the calculated values under the conditions of this experiment. The analysis results showed that the yield of cokes for the decomposition of blended fuels were lower than those of pure compound JP-10.