Investigations of the reduction of NO to N2 by reaction with Fe under fuel-rich and oxidative atmosphere

Abstract

The limitation of nitrogen oxides (NOx) emissions from stationary combustion chambers is still an important issue in the field of the natural environment protection. This paper describes the reduction of NOx in the presence of iron. A few new aspects of research describing the utilization of iron as an additive that influences NOx reduction at high temperatures are presented. In particular, the influence of the excess air number (λ) on the NOx removal efficiency in the presence of Armco iron was determined. A >50 % increase in the efficiency was achieved at λ = 0.6. The research was conducted using N2/NO mixed with a flue gas from carbon monoxide combustion. In addition, a correction factor (Arrhenius-type empirical equation) was determined, which enabled the calculation of the oxygen influence on the inhibition of the de-NOx reaction in the presence of iron. The NOx reduction was also tested using bearing steel samples. Finally, the use of iron in de-NOx processes under different combustion conditions is briefly reviewed and analyzed.