On the basis of the correlation between boiler load and oxygen content

the operation oxygen content characteristics of the boiler was discussed

and the reason for high NOxemission when the boiler was running at low load with the SOFA technology was investigated.Moreover

why the fuel staging combustion technology is matched with the boiler low load operation condition was theoretically analyzed.On this basis

the dual staging adjustable low NOxcombustion technology was proposed

which can be realized by changing the locations of primary air burner along the furnace height direction.Through regulation of the reburned fuel

the furnace combustion can be switched between the air staging combustion and fuel staging combustion

thus the disadvantages of the pure air staging or fuel staging combustion can be avoided.This technology has well feasibility and low risk

therefore

it is suitable to be used in large scale unit boilers.