Combustion chemistry of aromatic hydrocarbons

Aromatic hydrocarbons are important components of petroleum-based transportation fuels, biomass, coal, and solid waste, etc. The reaction kinetics of aromatic hydrocarbons largely determine the combustion characteristics and pollutant emission of vehicle/jet engines, power plants, and industrial reactors. While a few reviews have recently focused on aromatic hydrocarbons in gasoline surrogate fuels, thermochemical conversion of biomass/coal/solid waste, and combustion soot formation, a dedicated overview of research on the combustion chemistry of aromatic hydrocarbons is still lacking. In the last decades, valuable investigations addressing the reaction kinetics were reported based on the measurements from pyrolysis, oxidation, flames, shock tubes, and rapid compression machines, complemented by quantum chemistry and detailed kinetic modeling. Significant advances have allowed a better understanding of such physicochemical reacting system, from aromatic decomposition, oxidation, to pollutants formation. In the present review, aromatic hydrocarbons are systematically categorized to five common classes: basic, mono-substituted, multi-substituted, hydrogenated, and polycyclic aromatics. Fundamental aromatic combustion chemistry consists of the reactions of basic aromatic molecular structures. Then the aryl group strongly influences the reaction kinetics of aromatic derivates, which leads to very different combustion performance from those ordinary paraffins, olefins, and naphthenes. This paper seeks to provide an introduction to the knowledge gathered in the recent research, highlight pertinent aspects of this rapidly enriching information, and outlook the challenges towards fundamentally comprehensive aromatic combustion chemistry and practically efficient aromatic combustion model.