Fundamental Studies On Supercritical Initiative Cracking Of Endothermic Hydrocarbon Fuels

As the hypersonic flight comes ture, the power system of aerocraft-fuel will face severe request. With the adequate capacity of thermal absorbing, convenience for use and storage, and excellent combusbility, endothermic fuels have been researched extensively. Homogeneous initiator by use is one of the important ways to improve heat sink of fuels. In this paper, we studied the basic laws of n-dodecane supercritical initiative cracking, and supercriticial initiative thermal deposition of n-doecane and RP-3 in flow reactors, also studied the effects of several initiators on n-dodeane thermal oxidation stability by PDSC.The conversion, yields of gas, product distribution, kinetics and initiative mechanism from n-dodecane initiative craking by triethylamine(TEA), 3,6,9-triethyl- 3,6,9-trimethyl-1,4,7- triperoxonane(TEMPO) and 1-nitropropane(NP) were studied in the bomb reactor. The activity of the initiators exhibited in conversion and yields of gas decreased in the order NP > TEMPO > TEA. Initiators had little effects on the distribution of liquid products under the same conversion, and different initiators effected differently on the distribution of gas products. At the presence of secondary reaction in cracking reactions, the selectivity of 1-alkene in liquid products decreased with the increasing of conversion under the same conditions. The apparent energy from n-dodecane initiative cracking by NP decreased by approximately 30 kJ/mol, TEMPO 22.3 kJ/mol, and TEA did not change. Initiative mechanism was studied by GC-MS, and it was found that pure TEA produced enthane in a great measure, while TEMPO produced more enthane relatively and NP mostly produced propane.Supercritical initiative deposition from n-dodecane in flow reactors was studied by simulating the application environment of fuels. It was found that TEMPO had a good thermal stability on n-dodecane. The types of carbon which was produced by different initiators were somehow different, and most of deposits with NP was pyrolysis carbon. Supercritical initiative deposition from RP-3 was also studied, TEMPO had a good thermal stability on RP-3, while TEA produced more thermal oxidation carbon and deposition with NP produced more pyrolysis carbon. Initiators changed the shapes of coke deposition to a certain degree by SEM.The effects of TEA, TEMPO, NP, amyl nitrate and 1,2-propanediol dinitrate on n-dodecane thermal oxidation stability was studied by PDSC. The thermal oxidation stability of n-dodecane decreased in the order NP > TEA > TEMPO > amyl nitrate > 1,2-propanediol dinitrate。...