PURPOSE: To enable to control preceedingly the steam temperature and restrain the temperature fluctuation at the changing of a load by controlling of the difference of fuel supply quantity for each stage of burner, in case of the steam temperature control at the increasing and decreasing phases of a boiler load.
CONSTITUTION: Fuel adjusting valves 16A, 16B and 16C are provided independently for each stage burner 17A, 17B and 17C arrnged at the upper, intermediate and lower stage. The fuel supply quantity for each stage burner is made to be adjustable. An air box 20 is partitioned for each burner, each air damper 19A, 19B and 19C is provided independently for each air box 20A, 20B and 20C, the air supply quantity for each burner is made to be controlled. At the load increasing, the more fuel is aupplied to the upper stage side burner 17A, and the less fuel is supplied to the lower stage side 17C. Accordingly, the burning central point inside of a furnace 21 is raised, the rate of heat absorbing in a overheater 13 and a reheater 14 is increased. Thereby, the respondence ability aginst the lowering of the steam temperature at the load increasing can be improved by the preceeding control.
IIOKA YASUHIRO
SHIMADA YOSHIHIRO
