| 摘要 |
PURPOSE:To enable a re-combustion furnace to be operated approximately at a specified output, by a method wherein unburnt ash discharged from a main combustion furnace is stored in a hopper device, and according to an amount of ash stored, combustion in the re-combustion furnace is switched between unburnt ash combustion and coal combustion for operation of the furnace. CONSTITUTION:A layer temperature detector 11 is situated to a fluidized bed recombustion furnace (CBC) 1, and unburnt ash is fed from an ash feeding machine 7 to the CBC to maintain the temperature of a fluidized bed at a given value. Meanwhile, even during unburnt ash combustion, coal for assist combustion is fed through a coal hopper 12 with the aid of a coal feeding machine 13. If an amount of ash fed to the CBC is increased over an amount of ash from a fluidized bed type main combustion furnace, when an ash level is lowered to a position in which a low level detector 6 is operated, an ash feeder 7 is stopped, and an amount of coal fed to the CBC is increased to a value required for maintenance of a layer temperature at a given value. Since the feed of unburnt ash is stopped during coal combustion, an ash lever 4 is raised, and when the level is raised to a position in which a high level detector 5 is actuated, the ash feeder 7 is actuated to start the feed of ash to the CBC. Simultaneously, coal assist combustion rate setter is also actuated, an amount of coal stored is lowered to a given assist combustion rate, and a layer temperature is also increased to a given value.
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