Abstract: A pulverized coal combustion boiler 100 comprising: a furnace 50; a plurality of burners 6 for supplying and burning pulverized coal fuel in the furnace arranged at positions of a plurality of stages having different heights on a furnace front wall 51 and a furnace rear wall 52 of furnace wall surfaces forming the furnace 50, the furnace rear wall 52 arranged for facing the furnace front wall 51; a plurality of mills 2 arranged for supplying the pulverized coal fuel to the plurality of burners 6 arranged at each of the plurality of stages; and pulverized fuel pipes 5 arranged for distributing and supplying the pulverized coal to the plurality of burners 6 at each of the stages of the furnace front wall 51 and the furnace rear wall 52 from each of the plurality of mills 2.

Abstract: A fuel supply duct, which supplies a mixed fluid of a solid fuel and carrier gas to one or more burners provided on the walls of a furnace, is provided with a branching part, and each of a plurality of branch ducts, which branch out from the branching part, is connected to a corresponding burner. Also a damper, with which the tilt angle with respect to the direction of flow of the mixed fluid can be changed, is positioned in the fuel supply duct at the upstream side of the branching part so that a mutual difference will arise in the solid fuel concentrations of the mixed fluid supplied to the respective branch ducts. A fuel distributor for fuel supply duct is thus arranged. The tilt angle of the above-mentioned damper is adjusted to increase the concentration of solid fuel in the mixed fluid supplied to a specific burner. At a burner to which the high solid fuel concentration is supplied, stability of ignition and stable combustion of the ignited flame can be obtained during low load operation.

Abstract: A fuel supply duct, which supplies a mixed fluid of a solid fuel and carrier gas to one or more burners provided on the walls of a furnace, is provided with a branching part, and each of a plurality of branch ducts, which branch out from the branching part, is connected to a corresponding burner. Also a damper, with which the tilt angle with respect to the direction of flow of the mixed fluid can be changed, is positioned in the fuel supply duct at the upstream side of the branching part so that a mutual difference will arise in the solid fuel concentrations of the mixed fluid supplied to the respective branch ducts. A fuel distributor for fuel supply duct is thus arranged. The tilt angle of the above-mentioned damper is adjusted to increase the concentration of solid fuel in the mixed fluid supplied to a specific burner. At a burner to which the high solid fuel concentration is supplied, stability of ignition and stable combustion of the ignited flame can be obtained during low load operation.