Kotler V.R., Open JSC “VTI”
One of the most effective methods, providing a partial reduction of the already formed NOx to N2, is a three-staged combustion method, called in the U.S. and Western Europe as a reburning process. An essence of the method is that into the primary burners (working with the optimum excess air in terms of efficiency) only 75 ... 85% of all fuel is supplied. The remaining 15 ... 25% is fed into the intermediate zone of the flame (above the primary burners) with a great lack of air. This results in formation of the reducing zone, in which due to hydrocarbons and nitrogen-containing components (eg, amines) NOx is reduced.