Research on Flue Gas Recirculation Coupled Air Staging in an Industrial Pulverized Coal Boiler

In order to investigate the impact of flue gas recirculation coupled air staging on NOx emissions and the combustion process in pulverized coal boiler, we researched on the 30t/h industrial pulverized coal double-drum boilers. Contrast experiment was conducted regularly on pure flue gas and mixed flue gas recirculation combustion to investigate the impact of circulation ratio and oxygen concentration on the working conditions and NOx emission concentration in the furnace. The results show that air organizes combustion in the burner, the temperature is more uniform, and the NOx emission concentration is reduced when the circulatory flue gas enters into the furnace. When the flue gas circulation ratio is 20 %, the NOx emission reduction is up to 17 %. At the same time as the reflux flue gas volume is increased, the exhaust gas temperature gradually increases and the steam flow gradually decreases.