Abstract: A device for channeling boiler flue gas flow and injecting controlled amounts of ammonia upstream of a selective catalytic reduction (SCR) NOx removal system. A perforated plate and/or damper can be located within one or more channels to provide volumetric control through a channel. Flow conditioning devices such as static mixing tabs and/or flow straightening tube bundles can optionally be included in each channel to improve mixing and velocity profiles. Gas flow rate measurements made, for example via pressure taps, within one or more channels can be used to measure flow and provide feedback for improved ammonia-to-NOx mole ratio control.

Abstract: An integrated air foil and ammonia injection grid provides a plurality of air foils across a flue conveying flue gas. Each air foil has a leading curved edge and a tapered, pointed, trailing end. At least one injection pipe is positioned inside each air foil, and has at least one nozzle for injecting ammonia into the flue gas flowing across the air foils. Preferably, plural injection tubes are provided and positioned one behind the other in each air foil, and each injection tube in a given air foil has a length different than a length of the other injection tubes in the same air foil. A longest injection tube in a given air foil is located furthest downstream and proximate the tapered trailing edge and a shortest injection tube in the same air foil is located furthest upstream, remaining injection tubes in the same air foil being progressively shorter the further upstream any injection tube is located.

Abstract: Improvements in EL type pulverizers provide for longer wear life and reduced incidences of parts failures include: deep-dish contour grinding rings, tight tolerance ball tracks, heavy-duty top grinding ring flukes, larger diameter grinding balls, and an improved all-metal, integral snubber design for limiting the horizontal movement of the top grinding ring in order to increase the useful life of the pulverizer 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 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: Chlorine and sulfide species are separately introduced to a flue gas passing through a scrubber in order to remove the elemental and oxidized mercury from the gas through the precipitation of mercuric sulfide at near 100% efficiency.

Abstract: A method of welding together the parts of a boiler tube wall panel includes placing at least two parts of the panel to be welded together along a weld line and adjacent each other, and forming a weld along the weld line using a laser beam. The method can advantageously be used to weld boiler tube wall panels solely from one side of the panel. A GMAW process can also be used in combination with the laser beam to form the weld. Where the boiler tube wall panel includes a membrane between tubes, the membrane may be beveled.

Abstract: A method of corrosion protecting a tube having an end portion extending into a tube receiving hole of a mud drum of a boiler and the tube produced by that method. The end portion of the tube is provided with a corrosion resistant cladding layer which may contain chromium. Laser cladding is used to produce the corrosion resistant cladding layer, which advantageously tapers along a length of the end portion of the tube. The tube may be swaged before or after the cladding is applied and suitable heat treatments may be performed on the bare or clad tube to develop suitable properties in the tube, the cladding, or a tube-cladding interface.

Abstract: A pulverizer housing liner for the housing unit of an EL pulverizer is made up of an arcuate liner body having an inner curved surface forming a segment of the circular housing unit and two circumferentially spaced flutes fixed to the inner surface.

Abstract: A flue gas passage arrangement for a steam generator which permits adjustment of the heat transfer effectiveness of a final bank of heat exchanger surface to control a temperature of the flue gas flowing through and exiting from the flue gas passage and conveyed to a downstream NOx reduction device having a minimum operating temperature. The NOx reduction device is advantageously an SCR. Economizer heating surface is located within the flue gas passage, and a baffle plate extends through the flue gas passage and creates two flue gas paths there through. The economizer heating surface may be a single, common bank having a section located in both gas paths, or in only one gas path. Alternatively, two separate banks of economizer heating surface may be employed. A variable position damper is provided in one gas path, either below or above one section.

Abstract: A method of reducing the pressure drop in a downflow/upflow wet flue gas desulfurization (WFGD) system and of improving overall sulfur dioxide collection efficiency by converting the downflow/upflow WFGD system to an upflow single-loop WFGD system. The method includes the replacing of the downflow quencher and related duct work with a bypass for connecting the incoming flue gas duct with the upflow absorber, and the adding of a quenching zone in the absorber comprised of spray headers.

Abstract: A convection pass enclosure for a boiler comprising a front wall having a gas inlet for receiving gases from the boiler; right and left side walls connected to the front wall; a rear wall having a gas outlet, the rear wall being connected between the right and left side walls; and a roof, at least one of the front wall, right side wall, left side wall and rear side wall having a heat exchanger surface in the form of a horizontal spiral tube assembly.

Abstract: A scoop is used to collect a liquid slurry upstream of an internal collection tank. The scoop is in fluid communication with a downcomer, which receives at least part of the collected slurry, thereby maintaining a continuous flow of liquid slurry through the scoop to prevent plugging. Collected slurry can be removed for treatment from the scoop or the downcomer. In an application to a wet flue gas desulfurization (FGD) scrubber, the scoop collects an effluent slurry of partially reacted liquid scrubbing reagent and scrubbing byproducts before they drain into an internal reaction tank. Partially reacted liquid scrubbing reagent and scrubbing byproducts can therefore be withdrawn for treatment before the addition of fresh reagent alters the pH of the treatment stream.

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 spray level arrangement for spraying a liquid absorbent into flue gas flowing through a flue gas desulfurization absorber tower having a shell, includes a pair of elongated headers each having an inlet end for receiving liquid absorbent outside the shell, and an opposite end supported by a shell support at the inner surface of the shell. Each header extends through a penetration port of the shell and into the interior of the shell for supplying the liquid absorbent to the tower. A plurality of elongated branch lines are secured to each header and extend within the tower, each branch line having a supply end connected to the header and an opposite end supported on their own shell supports at the inner surface of the shell. A plurality of nozzles are secured to each branch. The nozzles are configured to spray the liquid absorbent into the flue gas within the tower. A beam in the shell has straps for further supporting the headers in the shell, if required.

Abstract: An hydraulic loading assembly for ball and ring coal pulverizers has a plurality of compression assemblies connected to a common hydraulic controller for exerting equal pressure simultaneously on each of the compression assemblies. The compression assemblies each have a hydraulic cylinder and piston located above and connected to a non-threaded rod which is in turn located above and connected to a compression spring exerting force on the top grinding ring of the pulverizer.

Abstract: A system for maintaining an optimal flue gas inlet to a boiler mounted SCR assembly in the flue of the boiler is accomplished by mixing the normal inlet feedwater to an economizer of the boiler with near saturation water from downcomers of the boiler to thereby raise the temperature of the flue gas passing across the economizer and raising the SCR inlet to the desired optimal SCR operation temperature.

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 flue for improving gas flow characteristics is used to supply a flue gas flow with particulate material entrained therein to a selective catalytic reduction reactor. Conduits have an inlet for receiving the gas flow and an outlet for emitting the gas flow. Compartments are disposed adjacent the conduits. Each compartment has an intake end positioned in flow communication with the conduit outlet and a discharge end for discharging the gas flow proximate the selective catalyst reduction reactor. The intake end of the compartment and the outlet end of the conduit are positioned on the same horizontal plane. A device supplies ammonia into the gas flow.