Advanced reburning for reduction of NOx emissions in combustion systems

Techniques for enhancing the burnout zone chemistry for NOx reduction are disclosed. The key parameters for the enhancement of burnout zone chemistry are: (a) a reaction temperature in the range from about 1300 DEG F. to about 1900 DEG F., and optimally in the range from 1400 DEG -1700 DEG F.; (b) a carbon monoxide concentration below about 0.5 percent; and (c) the presence of nitrogenous reducing species. By controlling the stoichiometry associated with reburning to produce a slightly fuel-rich region for selective reducing agent injection, reductions can be achieved at relatively low temperatures which approach those obtained by conventional catalytic reduction.