Pressurized internal circulating fluidized-bed boiler

A pressurized internal circulating fluidized-bed boiler for use in a combined-cycle electric generating system, comprising:

• a pressure vessel;
• a combustor disposed in said pressure vessel;
• a primary fluidized bed incinerating chamber having an air diffusion device provided at the bottom of said combustor and adapted to inject fluidizing air upwardly under a mass flow that is at least greater at one side than that at another side;
• an inclined partition wall provided above a portion of said air diffusion device where the mass flow is greater so as to interfere with the upward flow of the fluidizing air and thereby to deflect the air towards a portion above said another side of said air diffusion device where the mass flow is smaller;
• a thermal energy recovery chamber partitioned from said primary incinerating chamber by said inclined partition wall;
• a heat transfer surface means provided in said thermal energy recovery chamber for a passage of a heat receiving fluid therethrough;
• and
• an air diffuser provided at a lower portion of said thermal energy recovery chamber;
• wherein said thermal energy recovery chamber is communicated at upper and lower portions thereof with said primary fluidized bed incinerating chamber, a moving bed is formed above the portion of said air diffusion device where the injected mass flow is smaller so that a fluidizing medium descends and diffuses within the moving bed, and a circulating fluidized bed is formed above the portion of said air diffusion device where the mass flow of the fluidizing air is greater so that said fluidizing medium is actively fluidized and whirled towards a position above said moving bed and a part of said fluidizing medium is introduced into said thermal energy recovery chamber beyond an upper portion of said inclined partition wall, the formation of said moving bed and said circulating fluidized bed is effected by regulation of the amount of air injected upwardly from said air diffusion device and regulation of the fluidizing air injected from said air diffuser in said thermal energy recovery chamber causes the fluidizing medium within said recovery chamber to descend in a state of a moving bed for circulation.