Pyrolysis And Coking Of Endothermic Hydrocarbon Fuels

Being a new kind of propellant, the endothermic hydrocarbon fuel is also used as an idea coolant for the thermal management of hypersonic vehicles. This work focuses on the pyrolysis, coking and coking inhibition of the endothermic hydrocarbon fuels, which may offer important informations for the modification and application of this kind of fuel.The alkane n-octane, n-nonane,n-decane, n-undecane and n-dodecane were chosen as the model fuels. The effects of reaction temperature and time on the pyrolysis and coking of fuels were studied on a high-temperature pyrolysis apparatus. The gaseous products for thermal cracking of alkanes mainly contain methane, ethane, ethylene, propane, propylene and iso-butylene, and the liquid components include olefins, alkanes, benzene, polycyclic aromatic hydrocarbons and so on. It is obviously that temperature plays an important role on the chemical reaction of the model fuels. With the increase of the reaction temperature, the yields of cokes for five fuels increased rapidly.Three kinds of additives were studied in the present work. It follows that the effects of additives mainly depend on the content and species of additives. N, N’-Bis (salicylidene)-1,2-propanediamine (MDA) shows the most high performance in the three additives. As for the other two additives, the effect of Bentanol is superior to that of Polyisobutylene Succimide Dispersant (T154). Additives can also change the product distributions for thermal cracking of the fuel. Aromatic components in the liquid cracking products of the fuel with Bentanol and MDA are similar, but different from with T154.The effects of the composite additives on the pyrolysis and coking of four fuels (T-6、T-9、ZD-1and ZD-2) were researched. The coking yields of four blank fuel samples are as follows:ZD-1> T-9> T-6-ZD-2. The composite additives show good inhibition effects, which can reduce the coke contents of four fuels by61.14%>48.39%、53.76%and73.38%respectively compared with the blank ones.In order to improve the volumetric properties of n-alkane, high-density fuel JP-10was mixed with n-alkane fuel. The densities and viscosities were determined over the whole composition range for n-nonane, n-undecane, n-dodecane, n-tridecane, and n-tetradecane with exo-tetrahydrodicyclopentadiene respectively. The thermodynamic data may provide important information for studying blended fuels.