By using the dual-staged low NOx straight flow burners

the regulation of puverized coal concentration in primary air and velocity of primary air can be realized without limitation of minimum velocity of pulverized coal in the conveying pipeline

at the same time of enhancing the adaptability of boiler to coal sorts and heigtening the combustion stabilizing capability of boiler under low load

the emission of NOx can also be reduced.The results of application on one 1 025 t/h boiler with tangential firing show that the combination of said new type burners with air-staged combustion can reduce NOx emission by 30%

the increased amplitude of combustibles in fly ash being less than 1%

the variation of discharged flue gas temperature being less than 3 ℃

the variation of boiler efficiency being less than 0.1%

boasting good prospect of utilization.