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 NO_x 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.