Combustion characterization of benzene-doped, hydrogen-rich coke oven gas surrogate mixtures: H2/CH4/CO/N2/CO2

Abstract

This experimental study investigates the effects of benzene doping on the combustion and emission characteristics of hydrogen-rich, coke oven gas (COG) surrogate mixture, H2/CH4/CO/N2/CO2, to be called hereafter as COGb to distinguish it from and compare it with a different coke oven surrogate mixture, H2/CH4/CO, to be called hereafter as COGa. Unlike COGa mixture that includes only the major components of the industrial-grade coke oven gas composition, COGb also considers the minor components for the sake of a comprehensive understanding of the chemical and physical phenomena occurring at an industrial scale when burning coke oven gas mixtures. The purpose of benzene (C6H6) – as representative of benzol (BTX) – doping of the COG mixtures is to investigate the direct and indirect impact of aromatic compounds on NOx formation during the hydrogen-rich combustion process. Different levels of benzene (C6H6) doping (up to 5 % v/v) of industrial-grade, H2-rich COGb flames in a semi-industrial scale furnace under varying stoichiometric conditions allowed for collecting extensive data on temperature, exhaust emission, and chemiluminescence signature of important chemical radical species including OH⁎ and CH⁎. The results highlight a benzene-driven, three-way interaction between flame temperature, NO formation, and soot inception in the coke oven gas flames.

Keywords

• Hydrogen-rich fuels
• Nitrogen oxides (NOx)
• Aromatic doping
• Flame temperature
• Semi-industrial combustion furnace
• Sooty flames