| 摘要 |
PCT No. PCT/JP89/00883 Sec. 371 Date Nov. 29, 1989 Sec. 102(e) Date Nov. 29, 1989 PCT Filed Aug. 30, 1989 PCT Pub. No. WO90/02293 PCT Pub. Date Aug. 3, 1990.An internal recycling type fluidized bed boiler in which a fluidized bed portion of the boiler is divided by a partition into a primary combustion chamber and a thermal energy recovery chamber, at least two kinds of air supply chambers are provided below the primary combustion chamber, one for imparting a high fluidizing speed to a fluidizing medium and the other for imparting a low fluidizing speed thereto, thereby providing a whirling and circulating flow to the fluidizing medium in the primary combustion chamber. The fluidizing medium is moved downward in a moving bed in the thermal energy recovery chamber. Thermal energy recovery from exhaust gas is effected in a free board portion or downstream thereof, the cooled exhaust gas being guided to a cyclone, and fine particulate char collected at the cyclone is returned directly above or into a descending moving bed of the fluidizing medium in the primary combustion chamber and/or the thermal recovery chamber, whereby the char will not be immediately scattered to the free board portion and the char is sufficiently precipitated and it is possible to reduce NOx generated by combustion of coal or the like, in the bed.
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