Abstract: A circulating fluidized bed (CFB) unit utilizing a mechanical dust collector located in a vertical flue above at least one heat exchange surface, and at least partially underneath the floor of a non-vertical flue, includes a plurality of individual collection elements each having a downward bottom outlet for a flow of cleaned gas conveyed through the collection elements.

Abstract: A circulating fluidized bed (CFB) unit utilizing a mechanical dust collector located in a vertical flue above at least one heat exchange surface, and at least partially underneath the floor of a non-vertical flue, includes a plurality of individual collection elements each having a downward bottom outlet for a flow of cleaned gas conveyed through the collection elements.

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: 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: A water tube wall or heat transfer surface for use in a circulating fluidized bed combustor or reactor having reduced erosion at a transition between a protective refractory material and the upper wall.

Abstract: A circulating fluidized bed processor has a processor enclosure at least partially defined by a front wall and a rear wall spaced away from the front wall. A bottom wall is connected between the front and rear walls and a mechanism is provided for supplying primary air through the bottom wall for fluidizing a circulating bed in the enclosure. Another mechanism is provided for recirculating the bed from a top of the enclosure back to the enclosure. One or more secondary air plenum(s) are provided in the enclosure between the front and rear walls for supplying secondary air into the fluidized bed, above the bottom wall, so that secondary air reaches deep into the enclosure. The plenum(s) are formed of a waterwall which has a plurality of openings therein to allow communication of gases and solids therethrough from one side of the waterwall to the other.

Abstract: An improved CFB reactor or combustor arrangement has at least a first and a second group of impact type particle separators or U-beams with cooling surfaces located adjacent and immediately upstream of the second group of U-beams which serve to cool flue gas/solids flowing through the CFB before it reaches the second group of U-beams. By reducing the gas temperature in the vicinity of and entering the second group of U-beams, the U-beams can be made of less expensive materials and are thus less expensive to produce and maintain. The heat absorbed by the local cooling surfaces can be applied to heat a working fluid supplied to a turbine or other process.

Abstract: A drainable discharge pan apparatus for an impact type particle separator used on circulating fluidized bed (CFB) boilers employs a plurality of funnel shaped discharge pans located at a lower end of each of the impingement members in the impact type particle separator. The funnel shaped discharge pans prevent accumulation of collected particles thereon, allowing particles collected by the impingement members to fall therethrough, while preventing bypassing of flue gas around lower ends of the impact type particle separator. The outlet ends of the funnel shaped discharge pans provide substantially the same open area for the collected particles to fall therethrough as exists within each associated impingement member.

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.

Abstract: An internal particle separator having impingement members positioned within the furnace enclosure across and just upstream of the furnace exit opening. These impingement members are organized into at least two staggered rows that are positioned to fully cover the exit opening thereby allowing entrained particles to strike the impingement members and free-fall directly back into the fluidized bed to increase its density. A baffle plate is attached to the lower end region of the impingement members thereby obstructing the vertical gas passage between these members.

Abstract: This invention pertains to a discharge restrictor secured to the lower end region of impingement members installed in the flue gas path of a circulating fluidized bed boiler. The discharge restrictor incorporates a pivotable baffle plate that prevents the flue gas from bypassing the impingement members yet allows the particles that are collected to gather in an adjacent storage hopper. The baffle plate is normally biased to block access to the storage hopper until a sufficient mass of particles collect on the baffle plate thereby overcoming this bias. In doing so, the plate temporarily pivots to the open position enabling the particles to advance towards the storage hopper.

Abstract: A method and apparatus for controlling the combustion of multiple fuels, especially fuels having diverse combustion air requirements. A heating rate demand signal indicative of the heating rate desired is generated and is compared with a fuel based fuel heating rate signal. The larger of the two signals is selected to be an air demand signal that serves as set point for a combustion air controller. The flow rates of each of the fuels being burned is monitored and the resulting signals are scaled and summed to produce the heating rate signal. The fuel signals are also scaled by factors reflecting the combustion air requirements of the fuels. The signals are summed and combined with the fuel heating rate signal to produce a feedforward signal which in turn is combined with a signal reflecting the measured combustion air flow to produce an equivalent air heating rate signal.