A Detailed Kinetic Modeling Study of Benzene Oxidation and Combustion in Premixed Flames and Ideal Reactors

The pyrolysis and oxidation of benzene occupies a critical role in the combustion chemistry of practical fuels. Despite numerous experimental and numerical investigations, uncertainties still exist regarding even major benzene combustion features. Recent benzene premixed flame data sets offer a unique possibility for the judicious evaluation of mechanisms developed solely on the basis of a single flame. In this context, a validated detailed kinetic mechanism for benzene oxidation and combustion has been further developed and assessed against recently available premixed flame data and data from shock tubes and stirred and flow reactors. Speciation data from phenol and benzoquinone pyrolysis and oxidation are additionally used as validation targets. This approach provides the opportunity for a more systematic evaluation of uncertainties associated with experimental data obtained under similar conditions. A re-evaluation of the phenyl radical oxidation, phenol/phenoxy chemistry, and a cyclopentadiene submechanism is proposed in view of both new rate data and validation targets. Benzene oxidation is shown to be largely controlled by oxidation of phenoxy and cyclopentadienyl radicals, with C₅ and C₆ linearization reactions also being crucial. A notable exception is benzyne, which is predominantly consumed to a linear isomer. The mechanism is shown to successfully reproduce benzene experimental data covering a wide range of operating conditions. Phenol and benzoquinone pyrolysis and oxidation are also adequately captured. Further, the chemistry of C₁−C₄ small hydrocarbons is satisfactorily reproduced. Uncertainties related to both kinetic and thermodynamic data are evaluated. Finally, the study identifies aspects of benzene combustion chemistry where further work is required, most notably the rate and product distribution of the C₆H₅ + O₂ reaction