Experimental investigation of hydrogen enriched natural gas combustion with a focus on nitrogen oxide formation on a semi-industrial scale.

Combustion of hydrogen-enriched natural gas is a valuable short-term strategy for reducing CO 2 emissions from high temperature industrial heating. This paper presents several experiments on combustion characteristics and the formation of nitrogen oxides. The experiments included hydrogen contents up to 100% and fuel heat inputs up to 75 kW. Water-cooled lances were used to influence the furnace temperature. The analysis includes the distribution of furnace temperatures, the composition of flue gas, the cooling capacity of the lances under steady-state operating conditions, and OH*-chemiluminescence imaging of the near burner region. The presented results demonstrate the dependence of furnace conditions and NO X formation on various factors, such as different air inlet fluxes, furnace temperature, and fuel composition, for constant heat inputs. Efficiency increased by up to 5.5% and significant changes in flame shaped along with a maximum increase in NO X emissions when comparing natural gas to hydrogen was measured at 167%. [Display omitted] • Combustion of hydrogen-enriched natural gas with 0 to 100% H 2 • Experimental analysis of an industrial burner in a steady state, false air-free furnace. • Converged measurements for temperature, flue gas composition and cooling heat fluxes. • Dependence of NO X in mg/kWh on flame shape, temperature, fuel blend and air ratio. • Imaging of self-emitted OH*-chemiluminescence from turbulent jet flames. [ABSTRACT FROM AUTHOR]