Experimental and kinetic modeling study of styrene combustion

The aim of this work is to report new experimental data on styrene combustion and develop a kinetic model for styrene combustion. Three laminar premixed flames of styrene with equivalence ratios of 0.75, 1.00 and 1.70 were studied at low pressure (0.0395 atm) using synchrotron vacuum ultraviolet photoionization mass spectrometry. The JSR oxidation of styrene/benzene mixtures with three equivalence ratios of 0.50, 1.00, and 1.50 was studied at atmospheric pressure using gas chromatography. The mole fraction profiles of flame species and oxidation species were measured. A kinetic model of styrene combustion with 290 species and 1786 reactions was developed from our recently reported toluene model, and was validated on the new experimental data from this work and previous ignition delay time data. The O-atom attack reactions, H-atom abstraction reactions and other H-atom attack reactions were found to dominate the consumption of styrene. In particular, the O-atom attack reactions on the double bond of styrene play an important role in the JSR oxidation and the lean and stoichiometric flames, while the pyrolytic reactions have increasing contributions as the equivalence ratio increases. The phenyl radical plays a crucial role in the decomposition of styrene since it affords most of the reaction fluxes from styrene. In the aromatics growth process, phenylacetylene, the 1-phenylvinyl radical, the phenyl radical, and styrene serve as major precursors of polycyclic aromatic hydrocarbons (PAHs), leading to the high sooting tendency of styrene compared to toluene and ethylbenzene.