COMBUSTION AND HEAT EXCHANGING METHOD AND FACILITY THEREOF IN COMBINED-CYCLE FACILITY FOR FLUIDIZED BED COMBUSTION

摘要

PURPOSE:To obtain the optimized thermal efficiency value in performing desulpherization in the fluidized bed by a method wherein a flue-gas temperature at the entrance of a chimney is to be lowered as much as possible, and the flue-gas temperature at a outlet of freeboard is adjusted. CONSTITUTION:Without providing a combustion chamber and the second coal feeder system, a waste heat boiler 30 having an evaporator 27 and a feed water pre-heating tube 28, is provided adjoining the fluidized bed furnace 26, and an exhaust pipe of gas turbine 4 is connected to the bottom of the fluidized bed combustion furnace 26 for both purposes of fluid and combustion. On the other hand, another exhaust pipe 40 is connected to a freeboard 36 for the purpose of two stage combustion, further, the other exhaust pipe is also connected to the waste heat boiler 30 to recover the exhaust gas heat. As countermeasures to increase the temperature of the outlet at the freeboard 36, either change of particles size of solid fuels or installing of the insulating material member for convertible to take-off to cover the freeboard 36, comprising of water cooled wall 37 to absorb heat, which is used on-off basis of fixing and removing, thereby the exhaust temperature at the exit of the freeboard may be adjustable.