| 摘要 |
The invention is characterized in that the heat-transfer area of a steam generator (10) is designed somewhat oversized in a fluidized bed (6) in a PFBC power plant. By thereafter creating one or a plurality of non-fluidized zones (18) in the bed (6) during operation, the active heat-transfer area of tubes in the steam generator (10) may be adjusted. A certain proportion of the installed tube area is made passive as regards heat transfer. Defluidization is accomplished by shutting off fluidizing air (4) to the bed (6) below a vertical channel where a non-fluidized zone (18) is to be created. A barrier (15) in the form of a shelf or a stop plate is installed near the lowermost level (14) of the tube bundle (10), thus preventing fluidizing air (4) from reaching the bed (6) above the barrier (15). This results in the creation of an almost vertically standing non-fluidized zone (18) above the barrier (15). The cross-section area of the zone (18) in the horizontal direction is determined by the horizontal area of the barrier (15). |
