Abstract: A system and method for quickly cooling and de-pressurizing a boiler arrangement in the event of a plant power loss, a.k.a. a black plant condition. A steam discharge system injects steam from the steam/water circuit into the furnace, thereby both cooling components of the boiler arrangement and reducing pressure in the steam/water circuit. This reduces or eliminates the additional cost associated with providing extra capacity in a steam drum and/or an independently powered boiler water pump. The system and method is particularly useful for quickly cooling the U-beams of a circulating fluidized bed (CFB) boiler during a black plant condition. In application to boiler arrangements with a selective non-catalytic reduction (SNCR) system employing steam as a carrier for a NOx reducing agent, the steam discharge system advantageously uses the discharge nozzles of the SNCR system to inject the steam into the furnace.

Abstract: A circulating fluidized bed (CFB) boiler includes a reaction chamber, where a bubbling fluidized bed (BFB) is contained within an enclosure within the lower portion of the reaction chamber and contains an in-bed heat exchanger (IBHX) that occupies part of the reaction chamber floor. A plurality of in-bed secondary air nozzles comprise a plurality of tubes which are grouped together and run across the width of the BFB between the BFB enclosure wall and an outside wall of the CFB. The nozzles are positioned to prevent the deflection of solids falling onto the BFB from the CFB by the secondary air jets while avoiding a complicated structure that would interfere with gas and/or solids movement in the furnace. The nozzles' exit openings are flush, or almost flush, with the BFB enclosure wall.

Abstract: A system for feeding a primary oxidant to an oxy-fired circulating fluidized bed (CFB) boiler. The system includes a plurality of bubble cap assemblies each comprising a stem and a bubble cap with at least one exit hole, each bubble cap connected via a stem to at least one windbox, the windbox containing at least one manifold. A plurality of pipes are provided, each pipe located within a bubble cap assembly with an open end located either at, above or below the exit holes of the bubble caps and an opposite end connected to the manifold located inside each windbox. Recycle gas is piped into the windbox, to the stem, and exiting from the exit holes located in the bubble cap into the CFB. Oxygen is piped into the manifold, through the pipes and exiting through the exit holes located in the bubble cap.

Abstract: A circulating fluidized bed (CFB) boiler comprising a reaction chamber. A bubbling fluidized bed (BFB) is contained within an enclosure within the lower portion of the reaction chamber and contains an in-bed heat exchanger (IBHX) that occupies part of the reaction chamber floor. At least one non-mechanical valve, which includes an opening between the CFB and BFB and independently controlled fluidizing means located both upstream and downstream of the opening, is used to control the heat transfer to the IBHX by controlling the solids discharge from the BFB to the CFB. The elevation of the bottom of the opening is at or above the elevation of the fluidizing means. A flow control barrier may be located downstream of the opening.

Abstract: Alkali-containing bottom ash produced by a circulating fluidized bed (CFB) boiler is recycled to downstream spray dryer absorption (SDA) apparatus to more fully utilize the unused reagent present in the ash, and/or to reduce the amount of reagent used while not increasing NOx generation.

Abstract: An SNCR distribution grid for introducing a NOx reducing reactant into a flue gas flow. The grid is made of one or more elements which are formed by fluid-cooled tubes to which membrane pieces are attached, preferably by welding, to form conduits in between the tubes. The fluid-cooled tubes may be cooled by water and/or steam and the distribution grid is disposed in the flue gas flow. To admit the reactant into the flue gas, nozzles are provided in the membrane and the reactant is conveyed from a location external of the furnace or combustor enclosure, into the conduits so formed, and thence out into the Flue gas flow via the nozzles.

Abstract: A system and method for quickly cooling and de-pressurizing a boiler arrangement in the event of a plant power loss, a.k.a. a black plant condition. A steam discharge system injects steam from the steam/water circuit into the furnace, thereby both cooling components of the boiler arrangement and reducing pressure in the steam/water circuit. This reduces or eliminates the additional cost associated with providing extra capacity in a steam drum and/or an independently powered boiler water pump. The system and method is particularly useful for quickly cooling the U-beams of a circulating fluidized bed (CFB) boiler during a black plant condition. In application to boiler arrangements with a selective non-catalytic reduction (SNCR) system employing steam as a carrier for a NOx reducing agent, the steam discharge system advantageously uses the discharge nozzles of the SNCR system to inject the steam into the furnace.

Abstract: An integrated fluidized bed ash cooler for a fluidized bed boiler, particularly a circulating fluidized bed (CFB) boiler, employs at least two fluidized bed sections positioned in series along a solids flow path. Each section contains fluidizing means, the first section along the solids path being separated from a following section with a threshold. The first section contains means for measuring a bed temperature in the vicinity of the fluidizing means and at a higher elevation within the fluidized bed. Means are provided for removing oversized bed material from the first section to facilitate the removal of ash while minimizing the possibility of ash plugging during operation.

Abstract: An integrated fluidized bed ash cooler for a fluidized bed boiler, particularly a circulating fluidized bed (CFB) boiler, employs at least two fluidized bed sections positioned in series along a solids flow path. Each section contains fluidizing means, the first section along the solids path being separated from a following section with a threshold. The first section contains means for measuring a bed temperature in the vicinity of the fluidizing means and at a higher elevation within the fluidized bed. Means are provided for removing oversized bed material from the first section to facilitate the removal of ash while minimizing the possibility of ash plugging during operation.

Abstract: An inert impingement surface that is pliable and which, when set in motion, works to shed itself of particle deposits. The pliable surface may be formed of a plurality of coactive members that co-operate with one another to clean-off the particle deposits from each other's surfaces. The coactive members may be in the form of chains, rods, cables, wires, granular inert materials such as gravel or metal balls or other impact means. The pliable surface may also be formed of a heat-resistant material which is caused to experience a continuing shape change, thereby casting-off the particle deposits adhering to the surface.

Abstract: An inert impingement surface that is pliable and which, when set in motion, works to shed itself of particle deposits. The pliable surface may be formed of a plurality of coactive members that co-operate with one another to clean-off the particle deposits from each other's surfaces. The coactive members may be in the form of chains, rods, cables, wires, granular inert materials such as gravel or metal balls or other impact means. The pliable surface may also be formed of a heat-resistant material which is caused to experience a continuing shape change, thereby casting-off the particle deposits adhering to the surface.

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 made of a plurality of hung elements which are supported from at least one cooled support tube. The plurality of hung elements cooperate with one another at adjacent ends thereof to form a collecting channel which opens toward a flow of flue gas along the length of the support tube. Each hung element includes two mutually inverted U-shaped parts; the first U-shaped part opens towards the oncoming flow of flue gas, the second U-shaped part embraces the support tube, and the first U-shaped part is shifted relative to the second U-shaped part by some fraction of a height of the hung element. The hung elements may be made of metal or ceramic.

Abstract: A bubble cap assembly for use in fluidized bed boilers, furnaces, or reactors, has a bubble cap, a stem, and at least one pin. One end of the stem is inserted into the bubble cap. The bubble cap has outlet holes for delivering a fluidizing medium, typically into a bed of granulated material, but which prevent backsifting of the granulated material into the bubble cap. The bubble cap also has at least one insertion hole, through which a pin may be inserted. When the pin is inserted through the bubble cap insertion hole, it also occupies a groove or indentation on the stem thereby preventing separation or disassembly of the bubble cap and stem combination. An elastic gasket may be provided between the bubble cap and stem to form a fluid tight connection.

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: Apparatus for separating solids from flue gas in a circulating fluidized bed (CFB) boiler comprises plural vertical, impact type particle separators made of a plurality of hung elements which are supported from at least one cooled support tube. The plurality of hung elements cooperate with one another at adjacent ends thereof to form a collecting channel which opens toward a flow of flue gas along the length of the support tube. Each hung element includes two mutually inverted U-shaped parts; the first U-shaped part opens towards the oncoming flow of flue gas, the second U-shaped part embraces the support tube, and the first U-shaped part is shifted relative to the second U-shaped part by some fraction of a height of the hung element. The hung elements may be made of metal or ceramic.

Abstract: A bubble cap assembly for use in fluidized bed boilers, furnaces, or reactors, has a bubble cap, a stem, and at least one pin. One end of the stem is inserted into the bubble cap. The bubble cap has outlet holes for delivering a fluidizing medium, typically into a bed of granulated material, but which prevent backsifting of the granulated material into the bubble cap. The bubble cap also has at least one insertion hole, through which a pin may be inserted. When the pin is inserted through the bubble cap insertion hole, it also occupies a groove or indentation on the stem thereby preventing separation or disassembly of the bubble cap and stem combination. An elastic gasket may be provided between the bubble cap and stem to form a fluid tight connection.

Abstract: A collection element arrangement is provided having sleeve attachments near their lowermost ends which simulate a continuous sloping surface, or floor. The sleeve attachments upper surfaces forming the floor permit collected solids to flow down the sloping surface back into the furnace or reactor chamber. Stainless steel can be used for the collection elements and sleeve attachments since the floating floor accommodates differential thermal expansion between CFB components.

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 separator array for a furnace has large scale collection elements which can be formed from water-cooled tube walls and permit walk-through inspection and repair. The collection elements have direct impact surfaces, indirect impact surfaces and stagnation retainer surfaces. The array uses fewer, but larger collection elements than known separator arrays to provide at least the same solids collection efficiency while permitting the use of lower cost materials and easier inspection and repair.