| 摘要 |
PURPOSE:To reduce the amount of SOx, NOx and dust discharged from a fluidized boiler at the time of starting operation of the boiler by heating the fluidized bed by a starting burner, by recirculating exhaust gas from a downstream side of an economizer to a fluidizing air chamber while controlling the amount of exhaust gas to be recirculated through measurement of O2 contained in the exhaust gas. CONSTITUTION:In the fluidized boiler 1, combustion gas is carried through a hollow column 6, evaporating pipes 4a, 4b and the economizer 8 and then discharged to the outside from a duct 9 or the like. Here, a part of the duct 9 located downstreams of the economizer 8 is connected to a fluidizing air chamber 11 via a conduit 12, in which there are provided a recirculating fan 13 and a control damper 14. Further, in order to control the amount of O2, a conduit 17 having a damper 17a is also connected to the air chamber 11. With such an arrangement, the amount of NOx and SOx contained in the exhaust gas can be reduced by controlling the dampers 14, 17a and others by a control box 16 on the basis of the output signals from an O2-meter 15a in air chamber 11 and another O2-meter 15 disposed on the downstream side of the economizer 8, and recirculating exhaust gas to the air chamber 11 at the time of starting operation of the boiler. |
