The low nitrogen boiler is equipped with burners to achieve NOx emission less than 60mg/Nm3 (3.5% O2) without flue gas circulation and less than 30mg/m3 (3.5% O2) with flue gas external circulation system, which greatly increases the flexibility of the owner's selection and reduces the cost of the owner's future secondary transformation.In addition to the traditional low nitrogen burner, we also specially developed a negative pressure low nitrogen burner for the negative pressure furnace, which reduces the cost of boiler transformation.