Abstract: A method and apparatus for reducing and removing mercury in industrial gases, such as a flue gas, produced by the combustion of fossil fuels, such as coal, adds sulfide ions to the flue gas as it passes through a scrubber. Ideally, the source of these sulfide ions may include at least one of: sulfidic waste water, kraft caustic liquor, kraft carbonate liquor, potassium sulfide, sodium sulfide, and thioacetamide. The sulfide ion source is introduced into the scrubbing liquor as an aqueous sulfide species. The scrubber may be either a wet or dry scrubber for flue gas desulfurization systems.

Abstract: A method for producing chromium carbide coatings on steel provides a steel component having a surface which is carburized to contain at least about 0.40% by weight carbon and is followed by chromizing the surface to form a chromium carbide coating on the surface.

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 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 modified air heater gas inlet plenum for a tubular air heater which permits retrofit installation of additional flue gas environmental treatment equipment. A divider plate is located within the inlet plenum to subdivide it into first and second flue gas passages. The first flue gas passage created by the divider plate merely conveys the hot flue gas through the inlet plenum and into flues which convey the flue gas to the new equipment. Return flues convey the flue gas back to the second flue gas passage created in the inlet plenum which, in turn, conveys the flue gas into the tubular air heater heat exchanger tubes. By taking advantage of the large size of a conventional air heater gas inlet plenum, the first and second flue gas passages created by the divider plate still have sufficient cross sectional area so that acceptable flue gas velocities are preserved.

Abstract: A tube wall, division wall, or wing wall section (10) for a circulating fluidized bed boiler with improved erosion resistant characteristics has a reduced diameter tube section (40) adjacent the refractory covered by an abrasion resistant refractory tile (60). The refractory tile (60) is mounted to the reduced diameter tube section (40) with the upper edge of the refractory tile outside of or not extending beyond a solids fall line of solids in the fluidized bed to eliminate exposed discontinuities.

Abstract: A high velocity absorber has a lower larger diameter tank section for receiving a slurry at a liquid level in the. tank section, an upper smaller diameter absorber section where liquid scrubbing agent is mingled with flue gas from which impurities are to be absorbed, and a low pressure drop inlet assembly having a transition structure between the tank section and the absorber section for closing a gas flow path and a liquid flow path between the tank section and the absorber section. An inlet housing is connected to and communicates with the transition structure for inlet of flue gas into the transition structure between the tank section and the absorber section.

Abstract: A meter equipped with thermocouples which measure the combustion gas temperature used to calculate the heat flux at selected locations of a boiler furnace wall comprised of a series of tubes conveying pressurized water and separated by membranes. The meter extends through an opening in the membrane and is mounted on the outside of the furnace wall.

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: An access door for a boiler or furnace has a water-cooled jacket mounted on a door panel frame for use in high temperature regions of furnaces and boilers. The door is large enough to permit a stretcher to pass through unobstructed. The water-cooled jacket has a series of baffles which direct water in a serpentine path through the jacket. Plant water, as opposed to boiler quality water, may be used to cool the door. A viewing port may be provided in the door as well.

Abstract: A lance assembly for insertion into a steam generator chamber includes a hinged support for guiding the lance within the chamber which may be stored easily in a smaller space outside the chamber when not in use. One embodiment of the support has left and right side support guides formed from multiple hinged segments that surround the lance when inside the chamber. The hinges are axially offset from one another along a length of the assembly and pivot in opposite directions so that the guide is rigid inside the chamber yet allowing the lance to move therein. In an alternate embodiment, a single guide is used having multiple hinged segments. The hinged segments are locked in place immediately prior to being fed into the chamber. The segments may be folded over each other for storage in a smaller space.

Abstract: A combined removal system for separating carbon dioxide and sulfur oxide gases from furnace flue gases employs a single vessel having two chambers. The chambers are separated by a series of baffles and drains. The lower, primary chamber contains reagent and a delivery system for removing sulfur oxides (SO2 and SO3) from the flue gases. The upper, secondary chamber has a reagent, typically an amine solution, for removing carbon dioxide from the flue gases. The baffles and drains permit the flue gases to rise from the primary chamber into the secondary chamber, while collecting the amine solution which is used to trap the carbon dioxide. Alternatively, the primary and secondary chambers may be separated by a horizontal segment or a combination of horizontal and vertical sections.

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: A compound spin vane (CSV) for use in an air passage of a fossil fuel-fired burner. In one embodiment, the CSV is a multi-piece construction of platelike outer and inner vane elements connected to an intermediate platelike rail element. In another embodiment, the CSV includes at least two and possibly three vane portions, rigidly interconnected in spaced lateral relationship with respect to each other. If desired, the vane portions may be simple, curved planar surfaces, and may be arranged with trailing edges arranged at angles with respect to each other. The invention may be employed as a replacement for flat spin vanes found in secondary air passages of known single and dual register burners. When used in such manner in a single register burner, the invention changes secondary air flow characteristics so as to mimic those commonly found in a dual register burner.

Abstract: An improved main shaft for a coal pulverizer having a selected portion of the main shaft provided with an intervening material such as a thermally sprayed ceramic coating.

Abstract: An improved main shaft and assembly for a coal pulverizer having a circumferential groove at a predetermined location on the main shaft and in the yoke bushing to provide improved fretting resistance to reduce the occurrence of main shaft failure.

Abstract: A drumless natural circulation boiler system has a furnace enclosure with wall tubes and upper and lower headers connected to respective upper and lower ends of the wall tubes. At least one tangential steam/water separator is connected to a plurality of riser tubes that are also connected to the upper headers. The riser tubes return a steam/water mixture to the separator. Each riser tube is connected to the separator at a tangential nozzle for swirling the steam/water mixture in the separator for separating steam from water in the separator. At least one saturated connecting tube is connected to the separator for conveying steam therefrom. A downcomer is connected to the separator for conveying water from the separator and a plurality of supply tubes are connected between the downcomer and the lower headers. The separator includes a vertically extending cylindrical enclosure and a feedwater conduit is connected to the separator for supplying feedwater to the separator.

Abstract: An apparatus for separating solids from flue gas in a circulating fluidized bed (CFB) boiler includes a plurality of impact type particle separators mounted vertically to a wall of the CFB. The impact type particle separators being adjacently positioned and horizontally spaced. Each impact type particle separator includes a plurality of vertically mounted cooling tubes connected to a fluid circulating system. A slip fit element surrounds the cooling tubes. A cup shaped configuration is formed by side walls and a back wall. The side walls and back wall have a plurality of separate vertically aligned segments extending along the height of the impact type particle separator. Each vertically aligned segment is connected at its ends to an adjacent segment.

Abstract: A boiler attachment used to support a boiler component within the furnace or boiler chamber is composed of a similar material to the boiler component it is welded to, in order to eliminate the dissimilar weld failure. The boiler attachment is coated using a diffusion coating method to cover the attachments with a coating of aluminum, chromium, silicon or a combination thereof.

Abstract: A method and apparatus for reducing NOx emissions in a furnace having a main combustion zone with a waterwall and apparatus for supplying main combustion air and fuel to the main combustion zone, also reduces unburned carbon and waterwall corrosion in the furnace. The method involves providing at least one lower overfire air injector at a first level over the main combustion zone of the furnace for supplying overfire air to create a lower overfire air zone in the furnace over the main combustion zone and at least one upper overfire air injector at a second level over the lower overfire zone for supplying overfire air to create an upper overfire air zone in the furnace over the lower overfire zone. The overfire air in the lower and upper overfire air zones are supplied at a rate for reducing the stoichiometry in the main combustion zone which reduces unburned carbon and a corrosive reducing atmosphere in the furnace.