| Popis: |
The aim of this study was to investigate the mechanisms and kinetics reaction for hydrocarbon molecules composing a jet fuel. Five model hydrocarbons were selected (n-dodecane and its isomers blend, n-butylcyclohexane, 1,2,4-trimethylbenzene and 1-methylnaphthalene) and subjected individually to oxidation using the PetroOXY device, focusing on the beginning of autoxidation (ΔP/Pmax = 2 to 10 %). The consumption of oxygen was always higher than that of the parent hydrocarbons suggesting competitive reactions. Although the oxygen consumption is globally similar for the all alkanes, it is variable for the aromatics. This illustrates their reactivity confirmed by the induction periods (IP). An experimental protocol was developed to identify and quantify precisely the oxidation products formed in the gas and liquid phases, using analytical and chemical techniques. A link between the initial hydrocarbon's structure and the nature and number of carbon atoms in the oxidized products was evidenced. In addition, the tests performed at different temperatures (140, 150 and 160 °C) enabled the calculation of the overall and hydroperoxide dissociation kinetics constants reaction. Arrhenius parameters values obtained were higher for alkanes than for aromatics, confirming the "structure-reactivity" relationship of hydrocarbons. |
