Patent ID: 7392752

Claim:
A solid fuel boiler comprising: a furnace including a furnace wall to perform horizontal firing; a plurality of solid fuel burners mounted on the wall of said furnace, each including a fuel nozzle for spouting fuel and carrying gas therefor and an air nozzle for spouting air; a plurality of air nozzles (after air ports) mounted on a wall surface of the furnace at a downstream side of the solid fuel burners and spouting air; a duct through which a part of combustion exhaust gas recirculates to said furnace from a downstream portion thereof; a recirculation gas port via which the part of the recirculation gas is supplied into the furnace; and heat exchanger tubes disposed on said furnace wall and in a heat recovery area of said furnace, wherein said recirculation gas port is disposed between the burner positioned on an uppermost-stream side and said after air port, and is apart from an outer periphery of a throat portion (the most constricted portion) of the air nozzle in the one burner by 1.1 to four times a diameter of the throat portion, and a mixed fluid of the recirculation gas and air is supplied from said recirculation gas port.