Abstract: A circulating fluidized bed (CFB) boiler has one or more bubbling fluidized bed enclosures containing heating surfaces and located within a lower portion of the CFB boiler to provide a compact, efficient design with a reduced footprint area. The heating surfaces are provided within the bubbling fluidized bed located above a CFB grid and/or in a moving packed bed below the CFB grid inside the lower portion of the CFB boiler. Solids in the bubbling fluidized bed are maintained in a slow bubbling fluidized bed state by separately controlled fluidization gas supplies. Separately controlled fluidization gas is used to control bed level in the bubbling fluidized beds or to control the throughput of solids through the bubbling fluidized beds. Solids ejected from the bubbling fluidized beds can be returned directly into the surrounding CFB environment of the CFB boiler, or purged from the system for disposal or recycle back into the CFB.

Abstract: A circulating fluidized bed (CFB) boiler has one or more bubbling fluidized bed enclosures containing heating surfaces and located within a lower portion of the CFB boiler to provide a compact, efficient design with a reduced footprint area. The heating surfaces are provided within the bubbling fluidized bed located above a CFB grid and/or in a moving packed bed below the CFB grid inside the lower portion of the CFB boiler. Solids in the bubbling fluidized bed are maintained in a slow bubbling fluidized bed state by separately controlled fluidization gas supplies. Separately controlled fluidization gas is used to control bed level in the bubbling fluidized beds or to control the throughput of solids through the bubbling fluidized beds. Solids ejected from the bubbling fluidized beds can be returned directly into the surrounding CFB environment of the CFB boiler, or purged from the system for disposal or recycle back into the CFB.

Abstract: Apparatus for separating solids from flue gas in a circulating fluidized bed (CFB) boiler includes plural vertical, impact type particle separators made of cooling tubes located within the CFB in a plurality of staggered rows. One embodiment employs a plurality of stacked, slip fit elements having apertures which accept the cooling tubes. The slip fit elements cooperate with one another to form a collecting channel, typically U-shaped, which separates particles from flue gases conveyed across the particle separators. Shiplap joints in between the individual slip fit elements prevent gas and solids from leaking therebetween and allow for thermal expansion. Alternatively, the impact type particle separators include cooling tubes connected to one another to form a unitary structure. Pin studs welded to the cooling tubes and covered with a coating of refractory; ceramic tiles; metal or ceramic spray coatings; metal or ceramic castings; weld overlay; and/or shields provide erosion resistance.

Abstract: A CFB reactor or combustor having a selective catalytic reduction (SCR) system (150) employed downstream of the CFB reactor or combustor furnace (10) together with a dry scrubber system (220) to achieve enhanced NOx reduction.

Abstract: Apparatus for separating solids from flue gas in a circulating fluidized bed (CFB) boiler comprises plural vertical, impact type particle separators located within the CFB in a plurality of staggered rows. The impact type particle separators employ hung elements supported from fluid-cooled tubes which form a collecting channel, typically U-shaped, which separates particles from flue gases conveyed across the particle separators. By separating the support function from the collection shape required by functional performance considerations, the strength requirements of the material used to form the collection shape are reduced and the strength of the material from which the fluid-cooled support is made is much higher due to the lower operating temperature of the material comprising the fluid-cooled support, thereby permitting the use of lower cost materials.

Abstract: A CFB reactor or combustor having a selective catalytic reduction (SCR) system employed downstream of the CFB reactor or combustor furnace together with a dry scrubber system to achieve enhanced NO, reduction.

Abstract: Apparatus for separating solids from flue gas in a circulating fluidized bed (CFB) boiler comprises plural vertical, impact type particle separators made of cooling tubes located within the CFB in a plurality of staggered rows. One embodiment employs a plurality of stacked, slip fit elements having apertures which accept the cooling tubes. The slip fit elements cooperate with one another to form a collecting channel, typically U-shaped, which separates particles from flue gases conveyed across the particle separators. Shiplap joints in between the individual slip fit elements prevent gas and solids from leaking therebetween and allow for thermal expansion. Alternatively, the impact type particle separators comprise cooling tubes connected to one another to form a unitary structure. Pin studs welded to the cooling tubes and covered with a coating of refractory; ceramic tiles; metal or ceramic spray coatings; metal or ceramic castings; weld overlay; and/or shields provide erosion resistance.

Abstract: A CFB furnace or reactor unit is provided having enhanced circulation of the reagents finest particles. The improved circulation is achieved by recycling gas having entrained fine particles from a solids collection hopper connected to the solids separator back into the reactor. A system of one or more conduits connects the upper portion of the solids collection hopper with the reactor. The conduit system is equipped with means for recycling gas from the hopper to the reactor. The invention is an inexpensive system which permits recycling of the finest particles that would otherwise be carried over with the gas flow exiting the separator.

Abstract: A CFB reactor or combustor having an impact type primary particle separator collects solids particles from a flow of flue gas/solids and returns the collected particles along an inclined or substantially horizontal planar floor to a bottom portion of the reactor or combustor for subsequent recirculation.