Kotler V.R., Open JSC “VTI”

This method consists in selection of the flue gas part (5…30 %) from the flue duct at 300…400 °С and feeding these gases into the active combustion zone (preferably through the burners, using selected nozzles or in the air mixture, supplied for combustion). Flue gases reduce the maximum temperature in the flame core and oxygen concentration in the combustion zone. The first factor affects a rate of thermal NOх formation and the effect is higher with increase in the maximum temperature before recirculation input.