Directing against the fact of large variation range of fuel coal quality used for utility boilers

the combustion stability mechanism and adaptability to coal sort of the existing burners have been analysed

putting forward an assumption of once-through burner with adjustable central air flow. Through adjustment of the central air flow

the function of burner can be converted from that of bluff-body burner to that of sandwich air flow burner

and vice versa

making the range of adaptability to coal sort to be substantially expanded

being extremely suitable for combustion stabilization of boiler in the event of large variation of coal quality.