| 摘要 |
PURPOSE:To contrive to reduce NOx without increasing smoke dust in exhaust gas by a structure wherein a circular resistor is provided in the tertiary air supplying passage of a lowermost stage burner and yet and annular nozzle to jet main fuel pulverized coal in heavily swirling motion and an auxiliary fuel pulverized coal nozzle are arranged at each burner of the remaining stage burners. CONSTITUTION:Because swirling force is applied on the outer side of pulverized coal stream jetted from a nozzle 8 by means of a circular resistor 15 and yet tertiary air, the velocity of which is controlled by a trumpet-shaped body 13, is jetted, the improvement of combustion quality of the pulverized coal stream is resulted at the lowermost stage burner 1. Next, main fuel pulverized coal, which is carried with primary air and jetted from a main fuel nozzle 8A2, are mixed with swirling seconary and tertiary airs respectively jetted from nozzles 9A and 10A and burnt with high efficiency. On the other hand, auxiliary fuel pulverized coal, which is carried with recirculated exhaust gas and jetted from an auxiliary fuel nozzle 8A1, do not burn until it arrives recirculation combustion zone 17. NOx is reduced by the resultant reducing atmosphere and the reduction of NOx can be established.
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