Abstract: A burner assembly in which an inlet is provided for receiving a mixture of particulate fuel and air, an outlet extending at an angle to the axis of said inlet. A passage connects the inlet and the outlet for passing a portion of the mixture directly from the inlet to the outlet, and a chamber communicates with the inlet for receiving a second portion of the mixture. The chamber is constructed and arranged to swirl the second mixture portion and direct it towards the passage for passing to the outlet. As a result, particle fracture and friction losses are minimized and the burner assembly can operate at relatively low pressures.A burner section communicates with the inlet section and includes an inlet for receiving the fuel-air mixture from the outlet of the inlet section, and an outlet for discharging the mixture into a furnace.

Abstract: A burner for the combustion of coal dust in which a stream of primary air and coal dust mixture is conducted through a dust conduit connected to a primary dust tube. A secondary air tube surrounds the primary dust tube, and a tertiary air tube surrounds the secondary air tube. The secondary and tertiary air tubes are connected to a helically-shaped input housing, and a conically flared section extends from each of the secondary and tertiary air tubes. An angular momentum is applied in the dust conduit divides the primary air and coal dust mixture into high-dust and low-dust partial streams, so that the high-dust partial stream flows through the primary dust tube, and the low-dust partial stream flows through the primary gas tube.

Abstract: A nozzle for the injection of solid fuel in dust form into a combustion chamber, to be installed in correspondence with the outlet of a burner coaxially to the longitudinal axis of the burner, comprising a stationary annular part divided into coal ducts of a circumferential width that decreases towards outlet section to form coal-dust-rich air streams, a central duct for a coal-dust-poor air stream sideways delimited by the coal ducts and having an outlet end, a central member that is axially mobile within the central duct, for varying the cross section of a central passage delimited by the stationary annular part at the outlet end. Air ducts for the coal-dust-poor air stream are formed between each pair of adjacent coal ducts in the stationary annular part communicating with the central duct and having a circumferential width increasing toward the outlet end.

Abstract: In a fluidized-bed thermal reaction apparatus for burning or gasifying combustible matter containing incombustible components, deposition of incombustible components in a fluidized-bed furnace is prevented, and incombustible components are smoothly removed, thereby efficiently burning or gasifying combustible matter. The fluidized-bed thermal reaction apparatus has a weak diffusion plate, a strong diffusion plate, and an auxiliary diffusion plate, each having a large number of fluidizing gas feed holes, and an incombustible component outlet disposed between the auxiliary diffusion plate and the strong diffusion plate. A part of fluidizing gas is supplied from the incombustible component outlet, or the incombustible component outlet is provided to open horizontally. Thus, a continuous fluidized bed circulating stream is formed in the furnace bottom. The weak and auxiliary diffusion plates each has a downwardly inclined surface extending toward the incombustible component outlet.

Abstract: A coal combustor for combustion of coal in fossil burning plants, comprising a refractory including a reactor chamber, combustion chamber, and discharge chamber serially connected along a central longitudinal axis. The chambers define, respectively a reactor zone, combustion zone, and discharge zone extending through the refractory. A ceramic baffle insert is concentrically disposed within the forward end of the reactor chamber. The baffle defines at least one coal-gas passage extending longitudinally through the baffle and communicates an air-fuel mixture to the reactor zone. A reactor core tube is sealingly engaged by the baffle and in communication with the coal-gas passage. The reactor core tube extends longitudinally through a portion of the reactor zone and terminates in the combustion zone for communicating a coal-gas mixture from the coal-gas passage to the combustion zone.

Abstract: A pulverized coal burner includes a venturi for contracting a flow of a mixture of pulverized coal and primary air toward a central axis of a fuel nozzle 2. A spindle having a cone is provided coaxially with the central axis and gradually expands from an upstream side to a downstream side to cause the mixture to impinge thereon and diffuse. A column extends from the cone and is parallel to the central axis of the fuel nozzle, and a cone extends from the column and gradually narrows from an upstream side to a downstream side. A flow path divider, having a cone gradually narrowing coaxially with the central axis on the downstream side of the spindle, and a cylinder extending from the cone and being coaxial and parallel with the central axis of the fuel nozzle 2, coaxially divides the flow path.

Abstract: Apparatus for cooperation with an associated coal burning furnace which includes a Y-shaped distributor body having one inlet and first and second outlets and a splitter disposed in the body for dividing flow between the first and second outlets. The splitter has a generally V-shaped contour and the splitter comprises a base on the housing and a liner assembly mounted on the base. In some forms of the invention the liner assembly has a surface that is harder than the surface of the housing and the housing includes a removable access panel. The access panel may be dimensioned and configured to allow passage of the liner assembly into and out of the housing. The liner assembly may comprise an outer shell having at least some foamed material disposed therein and may include anchoring means disposed in the foamed material.

Abstract: A fluidized bed reactor for combusting material at an elevated temperature and generating heat. The reactor includes an upright reactor chamber delimited by at least one supporting wall having an internally refractory lined lower portion, the reactor chamber defining a space containing an abrading flow of fluidized bed material, a refractory lining provided on the internal side of the lower portion of the supporting wall, a recess provided on the internal side of the supporting wall above the refractory lining, the recess being defined by at least an upper endwall and a bottom, and a coating provided on the internal side of the supporting wall above the refractory lining. The coating extends from the upper endwall of the recess to the refractory lining, for recessing at least an upper border region of the coating.

Abstract: A process and apparatus for combustion of a solid carbonaceous material, for example coal, in which a mixture of the solid carbonaceous material and combustion air is injected into a combustion chamber and ignited, thereby forming a fuel-lean primary combustion zone. A gaseous fuel is injected into the combustion chamber in a region downstream of the primary combustion zone, thereby forming a fuel-lean secondary combustion zone. Temperature in the secondary combustion zone is in the range of about 1800.degree. F. to 2400.degree. F.

Abstract: In a vacuum housing (1), an inner duct (17) is disposed. Quadrupole magnets (superconducting coils) (4) is placed around the inner duct (17) is excited by a DC power supply (10). Quadrupole magnets (4) are cooled by liquid helium contained in a helium housing and outer tubes (2, 3) and is brought into a superconducting state. Pulverized coal X is ejected together with air Y from a header (11) through piping (12) and a valve (13) to a baffle plate (14). Pulverized coal is made to fall into the inner duct (3). Paramagnetic materials such as ash are attracted by magnetic force to the tube and are then collected by a collection tube (26). Combustible diamagnetic materials are collected by a combustible collecting tube (18) extending in the central axis. Intermediate materials are collected by an intermediate collection tube (23) and are put back to the head (11) through a bypass tube (25). There are no mechanical parts in the inner duct (3). Consequently, rotation loss and eddy-current heating are prevented.

Abstract: To a fluidized combustor bed there is passed particulate fuel via a fuel flow distributor which comprises a vessel for receiving a particular fuel from a fuel storage. The fuel is fed into the vessel of the fuel flow distributor from the fuel storage, whereupon the fuel is fluidized in a bed above a bed bottom in the vessel of the fuel flow distributor. The fuel flow distributor comprises at least two feed pipes with associated inlets located adjacent the surface of the bed in the fuel flow distributor, where fluidization gas which leaves the vessel via a feed pipe feeds out fuel to at least one nozzle is in the bed of the combustor. Additional gas is supplied to the feel pipes at the inlets thereof, such that the flow of fuel through an individual feel pipe can be controlled by controlling the gas flow supplied to the inlets of the respective feed pipes.

Abstract: Combustible is comminuted and dried, and metal and noncombustible are removed from the coarsely comminuted combustible. Then, the combustible is secondarily comminuted and separated into coarse combustible and fluff which is fine combustible. The coarse combustible of the separated combustible is fed onto a fire grate (2) of a refuse incinerator (1), and burned in flat bed combustion in a primary combustion chamber (4). On the other hand, the fluff is burned in suspended combustion in a secondary combustion chamber (7) with a combustion fluff burner (5) for incinerating combustible. Thus, refuse containing much plastics which is formed into fluff can be efficiently disposed of, whereby the amount of incineration is increased as a whole.

Abstract: A burner having lower emissions and lower unburned fuel losses by implementing a transition zone in a low NO.sub.x burner. The improved burner includes a pulverized fuel transport nozzle surrounded by the transition zone which shields the central oxygen-lean fuel devolatilization zone from the swirling secondary combustion air. The transition zone acts as a buffer between the primary and the secondary air streams to improve the control of near-burner mixing and flame stability by providing limited recirculation regions between primary and secondary air streams. These limited recirculation regions transport evolved NO.sub.x back towards the oxygen-lean fuel pyrolysis zone for reduction to molecular nitrogen. Alternate embodiments include natural gas and fuel oil firing.

Abstract: A heat exchanger and a fluidized bed combustion system and method utilizing same in which the heat exchanger includes a plurality of stacked sections. The sections include an inlet section for receiving the particles and a plurality of stacked sections and are arranged in such a manner that the particles are introduced into an upper level of the sections and pass through these sections to a lower level of sections before returning to the furnace. A portion of the stacked sections contain heat exchange surfaces for removing heat from the particles, and a multi-sectioned outlet compartment is provided to receive the separated particles from the heat exchange sections and directly from the inlet section and pass the particles back to the furnace.

Abstract: Information relating to combustion conditions within a fossil-fueled boiler that includes a plurality of burners adapted to produce flames combining to form a fireball is provided by acquiring data relating to the physical and temperature characteristics of the fireball with at least one imaging camera having optical and temperature measuring capabilities; receiving, storing and processing data received from the camera to provide data representative of the NO.sub.x content of the hot gases produced by the fireball; and transmitting the processed data from the processor to a monitor for display. Transmitted, processed data may include current, historical and target information relating to the physical appearance and temperature profile of the fireball.

Abstract: A coal gasification furnace includes a gasification chamber for producing therein a burnable gas from coal, a burner arranged on a side wall of the gasification chamber so as to inject coal and an oxidizing agent along a peripheral direction of the gasification chamber, a slag cooling chamber provided below the gasification chamber, and a slag tap partitioning the gasification chamber and the slag cooling chamber. The slag tap has a hole formed in a shape whereby the central portion of the hole is generally circular and oppositely directed slits extend outwardly from the central portion of the hole.

Abstract: A cyclone furnace combustion system and method in which a burner is mounted relative to a cyclone furnace for discharging a relatively fine particulate fuel in an axial direction into the furnace. Relatively coarse particulate fuel is discharged into the furnace in a tangential relationship thereto and air is provided in the furnace to support combustion of the fuels.

Abstract: A fuel injector for use in a furnace is provided. The fuel injector may include a generally tapered configuration and a nozzle having a plurality of open sections, which preferably have an elliptical configuration, arranged at the output for providing rich segregated fuel streams.

Abstract: An improvement of a coal firing device applied to coal gasifiers, boilers for power generation, etc. On the inner walls of a ceiling portion (4) of a firing furnace (3) and of a throat portion (2) thereabove, and of a diffuser portion (6) further thereabove, where necessary, plate-like vortex breaker(s) (1A, 1B) is/are provided. Vortex flow of gas in the vicinity of the inner wall surface around the throat portion (2) is thereby weakened and molten slag sticking on the wall surface is suppressed to be pushed up by the gas. There occurs neither staying of molten slag at the diffuser portion (6) nor scattering of slag, and blockade of furnace due to solid-phase slag does not occur.

Abstract: A combustion system in which a coal/primary air mixture is discharged from burners located in the corners of the furnace towards an imaginary circle disposed in the center of the furnace. Air is discharged from air nozzles also located in the corners of the furnace in two flow streams--one directed towards the center of the furnace in a combustion-supporting relation to the fuel, and the other along the inner surfaces of the furnace boundary walls to maintain an oxidizing atmosphere and minimize corrosion and slagging.

Abstract: An air damper assembly for a coal-fired furnace in which a damper sleeve extends between two spaced walls adjacent the furnace in a manner to define an air inlet. A threaded support member is connected to the damper, and a threaded shaft is in threaded engagement with the support member. Rotation of the shaft causes corresponding movement of the support member, and therefore the damper, to vary the size of the opening and therefore the amount of air introduced into the furnace.

Abstract: A fluidized bed combustion system in which a separator receives a mixture of flue gases and entrained particulate separated material from a fluidized bed in a furnace. A pressure seal valve connects an outlet of the separator to the furnace or a fluidized bed heat exchanger disposed adjacent the furnace for recycling the separated particulate separated material back to the furnace. The pressure seal valve includes a downflow leg, and upflow leg and a horizontal leg connecting the downflow leg to the upflow leg. A horizontal overflow leg is connected to the upflow leg and at least two return legs connect the overflow leg to the furnace. The separated material from the separator passes through the legs of the pressure seal valve and sometimes through a heat exchanger (if included) before reentering the furnace.

Abstract: A device for the combustion of solid fuels so as to provide complete combustion from the start and thereby reduce environmental influence and the generation of carcinogens, includes two chambers interconnected by a ceramic filter, which chambers have one or more heat sources, one chamber being adapted for drying and degasification of the fuel and the other chamber being adapted for combustion of the gas generated on degasification. The heat sources are mainly connected with the solid-fuel device to act at an initial stage until combustion takes place in a normal way so that complete combustion may be achieved from the start.

Abstract: A fossil fuel air burner nozzle is provided with a wall (22) at its inlet, in which are apertures (34) which narrow in a direction radially outward of the nozzle. Each aperture is axially aligned with a respective bluff member (18) at the outlet so as to deliver thereto a fuel air mix flow at a velocity which is graded in said radial direction so as to ensure flame retention on the bluff members (18).

Abstract: A burner for burning powdered fuel in air. The air is divided into concentric annular currents. A tube (6) conveys primary air or gas. The tube is surrounded by another tube (12). The second tube conveys secondary air. The exit of the primary-air tube inside the secondary-air tube is surrounded by an annular baffle (26). The baffle is open at each end, has secondary air flowing through it, and extends axially beyond the primary-air tube as much as 25% of the tube's outside diameter. The thickness of the gap (25) between the primary-air tube and the baffle is at least 1.5% of that diameter.

Abstract: A control system for a fuel-fired furnace and more specifically the control of the stoichiometric ratio of the combustion process occurring within the furnace of a steam generating power plant. The control system, when so employed, is capable of regulating the distribution of air flow to the combustion process such that the formation of oxides of nitrogen are maintained at acceptable levels. The control system includes in general a stoichiometric subsystem that determines the mass flow rate of air required to maintain the stoichiometric ratio within the combustion process; an override protection subsystem which ensures control precedence of the windbox-to-furnace pressure differential over the stoichiometry subsystem; and an overfire air subsystem that acts to apportion air flow amongst the various levels of overfire air within the boiler.

Abstract: A diffuser for a coal burner has a coal nozzle with an axis and an inner surface. The diffuser comprises a reducing area cone which has tapering upstream and downstream ends, for positioning in a coal nozzle at the coal nozzle axis. A frusto-conical shroud has a small diameter upstream end and a large diameter downstream end, positioned around the reducing area cone. A plurality of support legs is connected to the reducing area cone and extends radially outwardly through the shroud for connecting to the coal nozzle. Each of the support legs is inclined at an acute angle to the axis of the coal nozzle for evenly spreading pulverized coal supplied through the coal nozzle and past the diffuser.

Abstract: The present invention relates to a method of supplying coal and sulphur absorbent to a combustor with combustion in a fluidized bed. The coal is crushed and sorted into a fine and a coarse fraction. The fine fraction is mixed with water, possibly with oil and/or emulsifier, into a paste which is pumped into the bed of the combustor via a number of first nozzles. The coarse coal fraction is supplied to the combustor pneumatically in dry state, directly or via at least one lock hopper systems and a number of other nozzles. The invention also relates to a power plant for application of the method.

Abstract: A fluidized bed combustion system and method in which a recycle heat exchanger is disposed integrally with the furnace of a fluidized bed combustor. The recycle heat exchanger includes a plurality of stacked sections for receiving the recycled solids and are arranged in such a manner that the recycled solids are introduced into an upper level of the sections and pass through these sections to a lower level of sections before returning to the furnace. A portion of the stacked sections contain heat exchange surfaces for removing heat from the solids therein while another portion does not. The solids in the various sections are selectively fluidized to control the flow of the solids through the sections to control the temperature of the solids accordingly.

Abstract: A distribution half-cone for a granular or pulverized fuel, typically coal, burner is mounted within a burner nozzle thereof proximate to a burner elbow of the burner to provide a space or gap between an inner wall of the burner nozzle and the outer surface of the distribution half-cone of approximately 3/16 inch to prevent fuel roping and to minimize the pressure drop in the burner. The inlet of the distribution half-cone is formed as a sharp edge nozzle to minimize pressure drop in the burner.

Abstract: A burner system for a furnace includes horizontal rows of cell burners some of which contain a secondary air port vertically spaced from a coal nozzle. The cell burners are in the front and rear walls of the furnace. Near the side walls of the furnace, which are connected between the front and rear walls, additional double-burner cells are provided which include a pair of vertically spaced coal nozzles or burners. Either a single lower row or a lower and upper row of cell burners include the double-burner cells at the side walls. The double cell burners are operated at 1.0 or higher throat stoichiometry. This reduces corrosion at the side walls while only slightly increasing NO.sub.x emission.

Abstract: A static mixer device for mixing separate fluid streams entering the device in order to achieve a more uniform, or homogeneous, characteristic, such as temperature for example, in the resulting fluid mixture stream exiting the device. An exemplary embodiment of device comprises a series of parallel rectangular walls arranged in side-by-side, spaced apart relationship to form a series of rectangular spaces. The perimeters of these spaces are selectively closed to define respective first and second inlets and an outlet. The inlets sub-divide the respective entering fluid streams into sheet-like streams that are interleaved as they exit the device at the outlet. This interleaving of one stream with the other promotes increased homogeneity of the mixture stream in a shorter distance downstream of the confluence of the entrance streams.

Abstract: A mounting and linkage system for mounting an air or air-fuel discharge device for pivotal and axial movement relative to a furnace in a manner so that the device is isolated from the walls of the furnace. The system includes a linkage apparatus extending between the furnace walls and connected to the device for pivoting same.

Abstract: A structure of a boiler, of the type in which pulverized fuel is burnt within a square barrel-shaped furnace having a vertical axis, is improved so that ignitability is improved and the amount of NO.sub.x produced is decreased. Burners for injecting pulverized fuel-air mixtures are disposed at the central portions of respective edges in a horizontal cross-section of a furnace wall and are inclined downwardly with respect to a horizontal plane. Also, under air nozzles for feeding air are disposed under the respective burners.

Abstract: A coal-fired firetube boiler and a method for converting a gas-fired firetube boiler to a coal-fired firetube boiler, the converted boiler including a plurality of combustion zones within the firetube and controlled stoichiometry within the combustion zones.

Abstract: A new and improved method and apparatus for altering the firing pattern of an existing furnace of the type including at least one pair of vertically spaced apart burners mounted on a wall of the furnace and supplied with secondary air from a common windbox. The method involves cutting a rectangular panel from the furnace wall around a first burner wherein the burner is located asymmetrically toward a first panel end and spaced farther away from a vertically opposite second end of the panel. The cut-out panel is then reversed in orientation from end to end so that the first burner is then spaced farther apart at a greater distance from a second burner. The panel is reinstalled in the furnace wall in reverse orientation thereby providing a greater spacing or staging distance between the first and second burners producing a reduced level of NO.sub.x when the burners are fired.

Abstract: A method of feeding particulate material into a pressurized fluidized bed combustor including the steps of: feeding the particulate material from a source which is at a substantially lower pressure than that existing in the pressurized fluidized bed combustor into the upper end of an elongate, generally vertical gravity feed conduit constructed to have an inner bore which is substantially smaller at its lower end than at its upper end, and selecting the vertical height of the feed conduit and the extent of reduction in its bore over its length to ensure that the particulate material will move by gravity between the open input end of the conduit and the pressurized fluidized bed combustor notwithstanding the difference in pressure between the pressurized combustor and at the input end of the conduit.

Abstract: A method for combusting a fossil material so as to produce an exhaust stream having a low level of pollutants. The fossil material is introduced into a fluidized bed combustor which is operated at a temperature of at least approximately 1775.degree. F. to produce a partially cleansed exhaust stream having a low level of N.sub.2 O. SO.sub.2 is removed from the partially cleansed exhaust stream outside of the fluidized bed combustor to produce a cleansed exhaust stream having a low level of SO.sub.2. An apparatus is provided for performing the method of the invention.

Abstract: A fluidized bed combustion system and process is disclosed, in which full load stoichiometry is maintained at lower loads. The system and process includes an enclosure and a partition disposed in the enclosure to define a furnace section and an overfire air plenum section. A bed of combustible particulate material is formed in the furnace section and air is passed into the bed in quantities sufficient to fluidize the material and insufficient to completely combust the material. Overfire air is passed into the overfire air plenum, through control dampers in the partition and into the furnace section in quantities sufficient to completely combust the material.

Abstract: Apparatus and process for improving atomization and combustion of fuel containing solid particles, wherein the fuel containing solid particles is ejected from an outlet port having a conical or trumpet end-like internal wall surface and a fuel atomizing fluid is ejected from a plurality of bores present in the conical or trumpet end-like internal wall surface of the outlet port.

Abstract: A blade damper for use in fluid flow control devices having damper blades mounted on an axle and having extension ears mounted at opposite ends of the damper blades. The extension ears are mounted in a 90 degree relationship to the damper blades and are semi-circular at their boundary to allow for rotation with the damper blades. The extension ears prevent fluid leakage through boundary planes perpendicular to the axle when the damper is open thereby providing near linear side blade opening versus fluid flow characteristics.

Abstract: Method and apparatus for reducing the NOX levels in stack emissions of compact boilers and fluid heaters through selective injection of exhaust flue gases into the combustion process. Flue gas injection into the primary and secondary air of the burner along with flue gas injection directly into the combustion process is utilized. Injection of generated steam from a compact boiler, selectively injected into the combustion process is also provided.

Abstract: A burner and port combination for the combustion of a pulverized coal fuel plus air mixture comprises a throat and a burner nozzle positioned at a central area of the throat. The burner nozzle has an inlet for receiving the pulverized coal fuel plus air mixture and an outlet for discharging the pulverized coal fuel plus air mixture. A secondary air tube is positioned laterally adjacent the burner nozzle at each lateral side of the nozzle in the throat for providing a first portion of a secondary air to the throat. A plurality of vanes are positioned at an upper portion of the throat above the burner nozzle and the tubes and at a lower portion of the throat below the burner nozzle tubes for deflecting a second portion of the secondary air from the burner nozzle.

Abstract: A burner for a rotary kiln consists of a central pipe (5) for introducing an oil or gas lance, a first concentric pipe (8) for introducing primary air and a second concentric pipe (1) for introducing a mixture of solid fuel and carrier air into the burning zone of the kiln. The pipes (5, 8 and 1) form mutually annular channels, the primary air channel being located inside the solid fuel/air channel and at its end facing the burning zone being provided with nozzles mounted parallel to the axis of the burner, the primary air streams from the nozzles drawing the particles of solid fuel towards the core of the flame in the burning zone to increase the combustion and to reduce the NO.sub.x -content in the kiln exhaust gases. The burner is provided with a heat exchanger (14, 18 and 20) surrounding the portion of the burner projecting into the kiln to cool the burner and to increase the primary air velocity during injection into the burning zone.

Abstract: A device for the indirect heating of air or another gas at high pressure to a high temperature, consisting of a heat exchanger of a special construction submerged in a fluid bed of the "classical type", through which flows a fluidized hot, finely powdered bed material which is introduced (2) below the bed surface (3) and discharged through an overflow (5). The heat exchanger surface is formed by hairpin-shaped tubes (6) with legs of unequal length, the shorter legs thereof discharging into the upper bottom of an inlet chamber (7) and the longer legs thereof extending down through a tubular lead-through (9) between the bottoms of said inlet chamber (7), which lead-through is concentric with said tube leg and opens into the upper bottom of an outlet chamber (8), with an annular channel between said tube (6) and said lead-through (9).

Abstract: A burner for pulverized coal has a coal duct for pulverized coal and primary combustion air and a secondary combustion air duct such that the coal and primary air and secondary air mix outside the outlet nozzles of the duct in a mixing zone at which combustion occurs. Coal distribution means in the coal duct create, adjacent the outlet nozzle, at least one outer zone of flow spaced from the coal duct axis and at least one inner zone of flow nearer the coal duct axis. These are means for slowing flow in the outer zone relative to the flow in the inner zone, prior to the mixing zone. To achieve good mixing, and promote NO.sub.x reduction, the coal concentration in the outer zone is higher than in the inner zone. The slowing means may be radially inwardly projecting baffles.

Abstract: An in-bed staged fluidized bed combustion apparatus includes a reactor vessel having a grate for supporting a bed of sorbent and fuel in the vessel. The sorbent and fuel form a dense phase bed region. Fluidizing fluid for the combustion of the fuel is provided to the vessel through first and second delivery conduits. The first conduit delivers air to the bottom of the vessel. That air flows up through openings in the grate and mixes with the fuel and sorbent to support combustion. The second delivery conduit includes a distribution manifold and an array of spaced tubes that deliver secondary fluidzing air evenly across the reactor vessel at an intermediate point in the dense bed phase region. At least 55% of the combustion air is delivered through the second conduit. Accordingly, the dense bed phase region has a reducing zone formed in a lower portion thereof and an oxidizing zone formed in an upper portion thereof.

Abstract: A combustion process for nitrogen- or for sulphur- and nitrogen-bearing fuels wherein fuel combustion is divided, by staged oxygen (preferably in the form of air) injection, into at least two combustion zones. The first combustion zone involves providing fuel-rich stoichiometric conditions under which nitrogen chemically bound in the fuel (i.e. fuel-bound nitrogen) is substantially converted to molecular nitrogen. The second (final) combustion zone comprises at least two stages. In the first stage of the final combustion zone, combustion products from the first combustion zone are further combusted under a condition of fuel-rich stoichiometry, preferably at an oxygen/fuel stoichiometric ratio of from about 0.80 to about 1.0 and at a temperature of less than about 2200 K. In the second stage of the final combustion zone, combustion products from the first stage are combusted at an oxygen/fuel stoichiometric ratio of greater than about 1.0 and at a temperature of less than about 1500 K.

Abstract: A vertically aimable tip for a pulverized coal nozzle used in the boiler areas of coal fired, steam generating facilities. The nozzle tip comprises box-like outer and inner housings which are pivotally mounted as a unit to the outlet end of a pulverized coal conduit. A box-like end housing having integral splitter plates is loosely mounted in the outer housing in conforming and contiguous abutting relationship to the inner housing to complete the pulverized coal flow path. An air flow path is defined by the spacing between the outer housing and the combination of the inner and end housings. The combination of the end housing and splitter plates is held in place by means by slots and locking keys or tabs to permit differential thermal expansion. The splitter plates are hardfaced and extend upstream into the interior of the inner housing.

Abstract: A low NO.sub.x burner system for a furnace having spaced apart front and rear walls, comprises a double row of cell burners on each of the front and rear walls. Each cell burner is either of the inverted type with a secondary air nozzle spaced vertically below a coal nozzle, or the non-inverted type where the coal nozzle is below the secondary air port. The inverted and non-inverted cells alternate or are provided in other specified patterns at least in the lower row of cells. A small percentage of the total air can be also provided through the hopper or hopper throat forming the bottom of the furnace, or through the boiler hopper side walls. A shallow angle impeller design also advances the purpose of the invention which is to reduce CO and H.sub.2 S admissions while maintaining low NO.sub.x generation.