To improve combustion characteristics and hence make minimum the amount of scattering of a fuel non-combusted fraction onto the fluidized bed in a fluidized bed, boiler.
This fluidized bed boiler is adapted such that air and a solid fuel are incorporated into a fluidized bed composed of a fluidized medium, and hence supply water to a heat transfer pipe dipped in the fluidized bed. In the fluidized bed boiler, there is disposed an air dispersing plate 523 including a plurality of air nozzles 502 in a specific area including a portion just below a fuel insertion point being a tip end opening in a fuel nozzle 521 into the fluidized bed, and the number of holes in the air nozzle 502 of the air dispersing plate 523 located in the vicinity of the just under portion of the fuel insertion point is more increased than that of holes in the air nozzle 502 located in the other area. Hereby, combustion characteristics in the fluidized bed are improved without the use of a structure such as a bed distributor, and necessary and sufficient heat absorption in the heat transfer pipe in the fluidized bed is achieved to ensure inflow and outflow heat balance for the boiler. Further, there is restricted scattering of a non-combusted fraction to an empty tower part on the bed or to a high temperature gas piping part.
IWASE TETSUYA
MIYAMOTO EIJI
YAMASHITA YUKA
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