PULVERIZED COAL BOILER, ITS OPERATING METHOD, AND METHOD FOR REMODELING PULVERIZED COAL BOILER

摘要

PROBLEM TO BE SOLVED: To provide a pulverized coal boiler to recover the heat source when a combustion ash is melted and make an effective use of the energy while suppressing the discharge of NOx, to solve problems that a reduction apparatus must be increased in number to cope with generation of NOx when the combustion ash is melted and turned into slag in an ash melting furnace using the coal containing 10-20% ash, and the energy efficiency is worsened if the ash is discharged without collecting any heat source.;SOLUTION: In the pulverized coal boiler including a furnace 1 having a plurality of stages of burners 2, a dust collector 13 to collect the combustion ash in the exhaust gas of the furnace 1, and the ash melting furnace 4 to melt the combustion ahs and generate the molten slag, combustion ash carrying systems 16, 17 and 20 to feed the combustion ash collected by the dust collector 13 to the ash melting furnace 4 are provided, and an ash melting furnace outlet pipe 31 to feed the combustion gas generated in the ash melting furnace 4 is provided on a lower stage of a lowest stage burner 2 of the pulverized coal boiler. The exhaust gas of the ash melting furnace 4 passes through the atmosphere in the furnace 1 to reduce NOx. The heat generated in the ash melting furnace 4 is absorbed in the furnace 1, making an effective use of the energy.;COPYRIGHT: (C)2001,JPO