An experimental parametric study of gas reburning under conditions of interest for oxy-fuel combustion

An experimental parametric study on the NO reduction efficiency by reburning under oxy-fuel conditions has been performed through the gas-phase interactions between different gas mixtures and NO in a CO2 atmosphere, under flow reactor conditions in the 800-1800 K temperature range. The study provides a wide amount of experimental data on reburning under oxy-fuel conditions to be further used in modeling studies. A higher NO reduction is attained in a N2 atmosphere compared to CO2 under fuel-rich and stoichiometric conditions, although the efficiency is similar in both atmospheres under fuel-lean conditions. The formation of HCN in a fuel-rich environment is higher in N2 than in CO2 but comparable for other stoichiometries. The influence of the main parameters of the process under oxy-fuel conditions has been found to present similar trends to those observed in literature for reburning in air. A significant NO reduction can be obtained at moderately high temperatures, fuel-rich conditions, high values of the reburn fuel/NO ratio, sufficiently high residence times and low water vapor contents. C2H6 has been detected to act as a better reburn fuel as CH4, whereas CO itself is unable to reduce NO.