The Lean Oxidation of Iso-Octane in the Intermediate Temperature Regime at Elevated Pressures

Abstract

The oxidation of iso-octane has been studied in the past, primarily under stoichiometric conditions. Due to significant heat release from the oxidation of iso-octane in the intermediate temperature regime, excessive nitrogen was added to ensure safe operations and to slow the reactions in the use of flow reactors. Under these diluted stoichiometric conditions, all of the concentrations of iso-octane, oxygen, and nitrogen are significantly different from those in actual stoichiometric conditions. In this study, lean oxidation experiments of iso-octane in air (φ = 0.05) are performed in a high pressure flow reactor at 3, 6, and 9 atm in the intermediate temperature regime with reaction temperature in the range 915--950 K. Twenty-three hydrocarbon and oxygenated hydrocarbon intermediate species are identified and quantified as a function of time. A detailed chemical kinetic model is used to simulate these experiments. Comparison of predicted and measured species profiles shows that the model predicts the experimental data well including the shapes of species profiles. Based upon modeling results, the major chemical pathways are described.