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: 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 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.

Abstract: A circulating fluidized bed (CFB) reactor or combustor having an internal impact type primary particle separator which provides for internal return of all primary collected solids to a bottom portion of the reactor or combustor for subsequent recirculation without external and internal recycle conduits. The CFB reactor enclosure or furnace is provided with plural furnace outlets. This construction permits increased furnace depths and reduced furnace widths, resulting in a compact design.

Abstract: Bed temperature in a circulating fluidized bed (CFB) reactor is controlled by varying a recirculation rate of particles collected by a secondary particle separator back to the CFB reactor. Particle storage means, sized to contain sufficient inventory required for bed inventory/temperature control due to fuel/sorbent variations and/or load changes, stores particles collected by the secondary particle separator. The storage means can be either directly below the secondary particle separator or at a remote location. Particles collected by the secondary particle separator rather than by the primary particle separator are preferred due to their smaller size and lower temperature. A bed temperature control system controls the recirculation rate of these particles back to the reactor. Level sensing devices are provided on the storage means. A solids storage level control system that interacts with the bed temperature control system controls the solids inventory in the storage means via a purge system.

Abstract: A CFB reactor or combustor having an internal impact type primary particle separator provides cavity means and particle return means in an upper portion of the reactor enclosure to obtain direct and internal return of all primary collected solids to a bottom portion of the reactor or combustor for subsequent recirculation without external and internal recycle conduits.