Abstract: Disclosed are a process and apparatus for effecting chemical and/or physical reactions by means of solid-gas contact. The apparatus has a shaftlike reaction chamber widening in upward direction and divided into compartments by means of horizontal grids. The process is performed by introducing a particulate solid of about 0.5 to 5 millimeters particle size into the reaction chamber and passing a gas stream in upward direction through that chamber at an output sufficient to keep the particles in floating condition. A floating bed of solid particles will be formed in the reactors then and excellent solid-gas contact suitable for affecting chemical and physical reactions is provided hereby. A special embodiment relates to the removal of nitrogen oxides from flue gases with the aid of a particulate catalyst.

Abstract: The reactor includes: a lower zone (I) having a fast circulation fluidized bed; a zone having a dense fluidized bed (13) and located adjacent to the top of the lower zone, being separated therefrom by a dividing wall, the top layer of the dense bed receiving falling particulate materials, and its bottom layer returning these materials to the lower zone (I); and a higher zone having a fast circulation fluidized bed. The invention is applicable to boilers.

Abstract: Incineration apparatus for incinerating a particulate material comprises a furnace housing (2), feeding means (7) for feeding material to be incinerated into said housing (2), and gas supply means (6a-c) for introducing a gas into the material in a lower part of said housing (2) so as to form a fluidised bed (8). Said gas supply means (6a-c) is spaced from the walls of said furnace housing (2) such that said walls are insulated from the fluidised bed (8) by an insulating layer of particulate material not in a fluidised state.

Abstract: A fluidized bed combustion apparatus having an upright combustion chamber with a lower end at which a fluidized bed is formed and combustion takes place. First and second upright partitions are provided in the combustion chamber to divide the combustion chamber into a plurality of sections. The first partition divides the combustion chamber into first and second sections which are joined together by a turning space above an upper end of the first partition and the second partition is hollow and has an open, upper end in communication with the turning space to receive a portion of the combustion products therein. The lower end of the second partition is open to supply the combustion products to the fluidized bed.

Abstract: Hot gases from a pressurized fluidized bed reactor system are purified. Under superatmospheric pressure conditions hot exhaust gases are passed through a particle separator, forming a flitrate cake on the surface of the separator, and a reducing agent--such as an NO.sub.x reducing agent (like ammonia), is introduced into the exhaust gases just prior to or just after particle separation. The retention time of the introduced reducing agent is enhanced by providing a low gas velocity (e.g. about 1-20 cm/s) during passage of the gas through the filtrate cake while at superatmospheric pressure. Separation takes place within a distinct pressure vessel the interior of which is at a pressure of about 2-100 bar, and-introduction of reducing agent can take place at multiple locations (one associated with each filter element in the pressure vessel), or at one or more locations just prior to passage of clean gas out of the pressure vessel (typically passed to a turbine).

Abstract: An apparatus and method of operating a fluidized bed reactor for combusting refuse derived fuel is disclosed. The reactor includes a fluidized furnace section 30 and stripper/cooler section 80. A downwardly sloping grid 28 extends across the furnace section 30 and stripper/cooler section 80 to a drain 78 in the stripper/cooler section 80, and directional nozzles 38 disposed in the grid fluidize the beds in the furnace section 30 and stripper/cooler section 80 and forcibly convey relatively large particulate material across the grid 28, through the furnace section 30 and stripper/cooler section 80, and to the drain 78 for disposal. A refractory layer 36 is provided along the grid 28 surface to reduce the height of the nozzles 38 within the furnace section 30, thereby helping to prevent relatively large particulate material from becoming entangled with or stuck to the nozzles 38.

Abstract: A fluidized bed reactor in which a plurality of air bars are supported by a plurality of tubes in an upright enclosure. The air bars support a bed of particulate material and discharge air into the bed to fluidize the material. A cooling fluid is passed through the tubes to transfer heat from the air bars.

Abstract: The waste materials are gasified in a circulating fluidized bed in a gasification reactor, which is supplied with oxygen-containing gas. A gas-solids mixture is withdrawn from the upper region of the gasification reactor and is fed to a separator. Dust-laden gas and separated solids are separately withdrawn from the separator and the separated solids are recycled at least in part to the lower region of the gasification reactor. Temperatures in the range from 700.degree. to 1000.degree. C. are maintained in the gasification reactor. The dust-laden gas which is withdrawn from the separator has a heating value of about 3000 to 6000 kJ/sm.sup.3 and is fed to a combustion chamber and is combusted therein at temperatures from 1200.degree. to 1900.degree. C. Liquid slag is withdrawn from the combustion chamber.

Abstract: A black liquor gasification system intended for use as a replacement for a Tomlinson cycle, Chemical Recovery Unit, and which operates at a temperature below the ash melting temperature thereby removing the potential for smelt-water reactions and explosions. The subject black liquor gasification system is based on the use of a circulating fluidized bed operating at atmospheric pressure that produces dry, recoverable salts as well as low calorific gases to be used within the paper-making process.

Abstract: A biased air distribution grid is used to promote solids entrainment and dense bed internal mixing for the bed material of a fluidized bed reactor. The air distribution grid distributes air at a high velocity zone having a velocity ranging from 11 to 50 feet per second and a low velocity zone having a velocity ranging from 3 to 10 feet per second. The high velocity zone and the low velocity zone provide an improved lateral mixing for the reactor.

Abstract: A regenerative bed incinerator 10 is provided with a gas recirculation duct 80 through which a controlled amount of gaseous fuel is injected in the contaminated process exhaust gases 3 prior to admission to the regenerative bed incinerator 10 to increase the heating value of the process exhaust gases 3 so as to improve overall contaminated destruction efficiency for process exhaust gases which have a low level of combustible contaminants therein.

Abstract: The present publication discloses a method and an apparatus for drying the fuel used for firing a fluidized-bed boiler (1). The hot, inert solids of the fluidized bed are circulated by a regulated rate from the furnace (2) to a simple dryer (11) incorporated into the fuel feed line (7) to the boiler (1), whereby the fuel is dried and steam is generated. By virtue of controlled bed solids recirculation, a constant temperature of the dryer (11) can be maintained, thus permitting the omission of all heat transfer surfaces from the dryer (11). The nearly clean steam released from the drying process is routed from the dryer (11) to useful applications. (FIG.

Abstract: A process is set forth for directly controlling the quantity and particle size distribution of the solid inventory inside a circulating fluidized bed combustor. A portion of the bed ash is withdrawn from the combustor as bottom ash. The particle size distribution of the stream is adjusted, such as by a hammermill, to a specified distribution. Finally, a portion of the adjusted ash is re-injected into the combustor. The process may be facilitated by size classifying the bottom ash prior to size reduction.

Abstract: A circulating fluidized bed (CFB) system, and a method of operation thereof, provide a heat transfer zone containing primarily clean fluidizing gas providing advantageous conditions for superheating, while providing a large enough flow of solid material in the heat exchange chamber during both high and low load conditions to achieve the desired heat transfer capacity. The heat exchange chamber is provided near the bottom of a return duct connected between the particle separator and combustion chamber of the CFB, with a common wall separating the combustion and heat exchange chambers. Particles are reintroduced into the combustion chamber through a solid particle inlet (plurality of narrow, substantially horizontal, elongated, vertically stacked slots) in the common wall, and particles may pass directly from the combustion chamber into the heat exchange chamber through a passage in the common wall above the solid particle inlet.

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 fluidized bed reactor comprising a housing, and a nozzle grate disposed in the lower portion of the housing and serving to introduce a fluidizing fluid into the reactor. The nozzle grate consists of a plurality of approximately horizontally extending tubes and nozzles provided on such tubes. The tubes are detachably connected to the housing of the reactor and the housing of the reactor has at least one support for each tube, which support supports the tube as it is rotated about its longitudinal axis.

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: The present invention relates to a fluidized bed reactor in which olefins are polymerized or copolymerized in a bed formed by particles being polymerized and fluidized with the aid of a circulating gas. In the reactor, a circulating gas is fed from a gas space above the fluidized bed into the lower part of the reactor. The lower part of the reactor includes an annular space having an defined by an upwards tapering rotating conical surface and an outer wall defined by a downwards tapering rotating conical surface.

Abstract: Dried fuel is at least partly combusted, gasified or carbonized in the presence of cooled solid residue in a reactor. Hot solid residue, which is at temperatures in the range from 500.degree. to 1200.degree. C., is withdrawn from the reactor and is mixed with water-containing fuel in the receiving region of a mechanical mixer, without a supply of fluidizing gas. The mixture is transported with further mixing from the receiving region of the mixer through a mixing section of 1 to 10 meters to an outlet. A fuel-containing, substantially water-free mixture at a temperature in the range from above 100.degree. C. to 150.degree. C. is fed from the outlet of the mixer to the reactor. A mixer which comprises two intermeshing shafts, which rotate in the same sense, may be employed in the process.

Abstract: An apparatus and method of operating a fluidized bed reactor for combusting refuse derived fuel is disclosed. The reactor includes a fluidized furnace section 30 and stripper/cooler section 80. A downwardly sloping grid 28 extends across the furnace section 30 and stripper/cooler section 80 to a drain 78 in the stripper/cooler section 80, and directional nozzles 38 disposed in the grid fluidize the beds in the furnace section 30 and stripper/cooler section 80 and forcibly convey relatively large particulate material across the grid 28, through the furnace section 30 and stripper/cooler section 80, and to the drain 78 for disposal. A refractory layer 36 is provided along the grid 28 surface to reduce the height of the nozzles 38 within the furnace section 30, thereby helping to prevent relatively large particulate material from becoming entangled with or stuck to the nozzles 38.

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: A circulating fluidized bed reactor comprises a reaction chamber (10) with an upwardly directed flow of gas with entrained particulate solid material, a separator (18) for separating the particles from the gas flow, and a particle recycling system (23) for controlled return of the particles to the reaction chamber (10). The particle recycling system (23) may comprise means (47) for controlled return of the particles in a non-cooled condition and superposed fluid beds (55 and 59) which may be connected in parallel or in series as desired for returning particles to the reaction chamber in a more or less cooled condition. The reactor may also render it possible to return various fractions of the particles into the reactor chamber (10) at different levels.

Abstract: A fluidized bed reactor having a furnace strip-air system and method for reducing heat content and increasing combustion efficiency of drained furnace solids in which a bed of particulate material is supported in a furnace section. A portion of the bed receives a greater amount of fluidizing gas to increase the stoichiometric conditions in the bed portion, strip relatively fine material from the particulate material in the bed portion and increase the amount of heat transferred to the flue gases. A cooler is located adjacent the furnace section for receiving particulate material from the bed portion.

Abstract: A rotary fluid bed gasifier having a combustor assembly and a stationary feed conduit which is capable of feeding a carbonaceous material and/or limestone from outside of the gasifier and delivering this material to the gasification chamber of the combustor assembly through a rotating wall of the combustor assembly, wherein the stationary conduit is centrally disposed within the combustor assembly such that the rotatable inner assembly of the combustor assembly revolves about the stationary conduit.

Abstract: Waste materials including chlorine compounds are charged into a fluidized-bed gasification furnace having a first fluidized bed of which fluidizing medium comprises CaO. HCl produced from the waste materials is reacted with CaO which is the fluidizing medium and changed into CaCl.sub.2, and then discharged from a discharge pipe together with unburned materials. Gas generated as a result of the above-described reaction flows together with CaCO.sub.3, which is supplied into a second fluidized bed of a fluidized-bed combustion furnace located above, and are burned within the second fluidized bed. CaO is supplied from the second fluidized bed into the first fluidized bed via a supply pipe. In this manner, HCl produced from the waste materials is effectively removed.

Abstract: This invention relates to a novel horizontal fluid bed reactor, which in a single unit, provides for the polymerization of monomer to polymer and mixed monomers to co-polymers. Within one reactor shell the reactor contains a plurality of polymerization stages which permit the achievement of narrow residence time distribution of the produced polymer. This arrangement also creates a sufficiently tight subdivision of the reactor volume which permits a plurality of gas circulation stages of different gas compositions, as well as, polymerization temperatures.

Abstract: Distributor device comprises at least one lower and/or one upper stationary distributor device for distribution of fuel in the form of gas and particles in a fluidized bed and is arranged above fuel feed nozzles in the bed, or at or above the upper limit of the bed. The task of the distributor device is to spread fuel, rising upwards in the bed, more evenly over a large area in the bed and to create turbulence above the bed. This is achieved by designing the distributor device with a mid-portion and upwardly-inclined wing-like members or the cone to bring about even distribution of fuel by forcing the fuel to follow an outwardly-directed horizontal or obliquely upwardly-rising flow of fuel.

Abstract: A regenerative thermal oxidizer for oxidizing a contaminant in an air or other gas stream includes a heat transfer material which heats the incoming air and collects heat from the exiting air. The direction of flow of the air through the oxidizer is periodically reverse for the regenerative heat exchange. When flow is reversed, a quantity of untreated air in the oxidizer which would otherwise be discharged to the atmosphere is collected in a purge chamber which surrounds the lower portion of the discharge stack. The untreated air enters the bottom of the chamber and the air already in the chamber is forced out from vent holes in the top of the chamber into the stack. The untreated air in the chamber is fed back to the oxidizer through the inlet of the blower feeding the oxidizer while clean air is drawn into the chamber from the stack through the vent holes.

Abstract: A combustion subsystem with a circulating fluid bed boiler (12) having a pantleg configuration. The boiler includes front (22) and back (24) walls with external fluid bed heat exchangers (48) integral therewith. In addition to the conventional fuel inlets (54) which provide for entry of fuel into the side walls of the boiler through conduits connected to the seal pots (36) of solids recycle cyclones (30), supplemental fuel inlets (63, 66, 70, 72) are provided on the front and back wails of the boiler through the fluid bed heat exchangers or between adjacent fluid bed heat exchangers. The invention improves combustion efficiency in large boilers by reducing the theoretical mixing length within the boiler.

Abstract: A gas distribution system employing an array of parallel gas inlet pipes and a pair of transverse gas inlet pipes located below the first group of pipes to fluidize a particulate bed in a reaction vessel and to remove non-fluidizable particles that may be introduced into or form in the bed.

Abstract: A fluidized bed reactor and system and method utilizing same for the combustion of waste fuels in which the reactor vessel is divided into three vessels. Waste fuel is introduced into the fluidized bed within one vessel where it is mixed with bed make-up material that is controlled to provide an ideal environment for the generation of pyrolytic gases. The fluidized bed material is pneumatically and gravitationally conveyed downwardly, and injected into a fluidized bed within the second vessel where the involatile organic material undergoes combustion in an oxidizing atmosphere. The bed material in the second vessel is pneumatically conveyed upwardly and divided into two portions, one of which is recycled back to the first vessel. The other portion of the bed material in the second vessel is circulated to a fluidized bed within the third vessel where heat is recovered.

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: Mixed waste containing organic constituents and low level radioactive waste is remediated in a circulating fluidized bed combustor. Three separators are used to filter the flue gas and separate fine radioactive material from coarse non-radioactive material thereby concentrating the radioactive portion. A primary separator separates large material such as sand, lime, flyash or unburned fuel particles from the flue gas leaving the furnace of the combustor. The flue gas is then passed to a secondary separator for the collection of finer particles. In turn, the flue gas is passed to a tertiary separator for the collection of the finest particles of the flue gas containing low level radioactive waste. Solids entrained in the primary separator are recycled back into the bed of the combustor through an L-valve. Solids entrained at the secondary separator are also recycled back into the bed.

Abstract: A fluidized bed combustion method utilizing fine and coarse sorbent feed to control the temperature of a cooling fluid such as water or steam circulating through a fluid flow circuit of a fluidized bed combustor. Fuel particles, such as coal, along with relatively fine and relatively coarse sorbent material, such as limestone, are fed into the furnace section of a fluidized bed reactor. The fuel is combusted, and a fluidizing gas such as air is introduced into the furnace section. Flue gases and entrained material pass from the furnace section, and the entrained material is separated from the flue gases. The separated entrained material passes to a recycle heat exchange section and is cooled before being passed to the furnace section. The recycle heat exchange section is provided with heat exchange surfaces which form part of a fluid flow circuit to transfer heat from the separated entrained material to a cooling fluid such as water or steam which is circulating through the circuit.

Abstract: A method and a device for preheating a particulate fluidized bed which is supplied with air for fluidization of bed material and for combustion of main fuel through gas paths that include fluidization members for injection and distribution of the air over the fluidized bed. The bed material is preheated to the ignition temperature for the main fuel used in the fluidized bed by members arranged in the gas paths for combustion of starting fuel. These members are designed and arranged so that the air is supplied to the fluidized bed along the same path through gas paths and fluidization members upon preheating with starting fuel as upon combustion of main fuel in the fluidized bed. The members for combustion of starting fuel are arranged in the fluidization members and comprise fuel injectors, fuel pipes, ignition members and control members.

Abstract: A fluidized bed combustion system in which a separator receives a mixture of flue gases and entrained particulate material from a fluidized bed in a furnace. A pressure seal valve, in the form of two ducts, connects an outlet of the separator to the furnace for recycling the separated particulate material back to the furnace. A pressure head builds up in one of the ducts and air is introduced to the other duct to dampen pressure fluctuations in the furnace and promote the flow of the particulate material back to the furnace.

Abstract: A reactor chamber of a fluidized bed reactor has an internal circulation of particles. Larger recirculated particles are prevented from contacting heat transfer surfaces by classifying particles adjacent the bottoms of the reactor chamber using a particle chamber having a barrier wall with holes or slots of a maximum dimension of less than about 30 mm. The heat transfer surfaces may be disposed in the particle chamber. Larger particles flow down the walls of the particle chamber into the reactor chamber, and some fine particles within the particle chamber are preferably recirculated back to the fluidized bed. The barrier wall is preferably the top wall of the particle chamber, and may be refractory lined with furrows, and/or may be formed of water tubes connected together by fins, with the holes or slots formed in the fins.

Abstract: A circulating fluidized bed combustion process which uses a sorbent to react with sulfur oxides employs a process for fracturing the sorbent particles to expose unreacted sorbent in the core of the particles to increase the sorbent utilization. The particles within the circulating bed are fractured by injecting water either as a liquid or as steam.

Abstract: The present invention concerns a method of reducing polluting emissions from a circulating fluidized bed combustion installation including a furnace from which the dust is recovered at least in part by a cyclone, the partially dedusted gases output by the cyclone passing through a recovery boiler, and then into a dust filter, in which method a desulfurizing agent is inserted into the furnace. According to the invention, downstream from said recovery boiler, and upstream from said dust filter, the flue gases are desulfurized in semi-humid manner in a reaction enclosure provided with a water injection inlet. Downstream from said dust filter, the resulting desulfurization products are thermally oxidized.

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: A process and apparatus for cooling coal dried in a fluid bed reactor are disclosed in which heated dried coal is separated into coarser and finer fractions and the coarser and finer fractions are separately cooled.

Abstract: A circulating fluidized bed combustor comprises a fluidized bed combustion chamber, a recirculating system for recirculating fluidized solids through the combustion chamber, and a plurality of fluid injection nozzles disposed around the walls of the combustion chamber above the loop seal returns for injecting a high velocity fluid for improved mixing gases and solids in the combustion chamber.

Abstract: In association with a circulating fluidized bed reactor, a bed of particles is established in the return duce for particles from the particle separator to the combustion chamber. Inlet openings extend from the bed of particles into the combustion chamber, and the height of the particle bed is maintained above the inlet openings a sufficient distance to form a gas seal. The particles in the bed are fludized, and also transporting nozzles are arranged at different levels for transporting the particles from the bed through the inlet openings into the combustion chamber. Heat exhangers (e.g. superheaters) may be provided in the bed to recover heat from the particles.

Abstract: A fluidized bed apparatus comprising a pair of separated fluid bed enclosures, each enclosing a fluid bed carried on an air distributor plate supplied with fluidizing air from below the plate. At least one equalizing duct extending through sidewalls of both fluid bed enclosures and flexibly engaged therewith to communicate the fluid beds with each other. The equalizing duct being surrounded by insulation which is in turn encased by an outer duct having expansion means and being fixed between the sidewalls of the fluid bed enclosures.

Abstract: A fluidized bed steam generation system and method in which recycled flue gases are used to assist in passing solid particulate material from the separator, through the loopseal, and back into the furnace. The solid particulate material separated in the cyclone separator and passed back to the furnace is assisted by recycled flue gases which have passed through the heat recovery section, an air heater, and a baghouse. The use of the recycled flue gases decreases the oxygen content which can cause oxidizing or burning of the solid particulate material which results in overheating or agglomeration of the loopseal.

Abstract: A process and system for treating organic waste materials without venting gaseous emissions to the atmosphere. A fluidized bed including lime particles is operated at a temperature of at least 500.degree. C. by blowing gas having 20%/70% oxygen upwardly through the bed particles at a rate sufficient to fluidize same. A toxic organic waste material is fed into the fluidized bed where the organic waste material reacts with the lime forming CaCO.sub.3. The off gases are filtered and cooled to condense water which is separated. A portion of the calcium carbonate formed during operation of the fluidized bed is replaced with lime particles. The off gases from the fluidized bed after drying are recirculated until the toxic organic waste material in the bed is destroyed.

Abstract: In a fluidized bed reactor particles are internally circulated, moving down the walls forming the reactor chamber. A particle chamber having a particle gathering top wall with a horizontal projection area A is disposed in the downward flow of particles. Openings (e.g. holes or slots) with a controlling dimension of about 30 mm or less are provided in the top wall, the openings having total open area B less than half the area A. Heat transfer surfaces may be disposed in the particle chamber.

Abstract: The invention provides an improved method and apparatus for feeding solids to a fluidized bed reactor. A back pressure control valve regulates the pressure drop between the pressure above a solids column in a standpipe and the pressure in the reactor. Solids are fed from the standpipe via a conduit without valve means, the conduit contains a bend of an angle greater than the angle of repose of the solids.

Abstract: Emissions of nitrous oxide (N.sub.2 O) are lowered in a fluidized bed reactor utilizing two-staged combustion. A lower region of the furnace section is operated under substoichiometric conditions so that combustion in the lower region is incomplete, thereby inhibiting formation of N.sub.2 O and nitrogen oxides (NO.sub.x). An upper region of the furnace section is operated under oxidizing conditions to promote further combustion. An amount of particulate material is present in the upper region, and this amount of particulate material in the upper region is controlled to maintain a temperature in the upper region for destroying N.sub.2 O formed during combustion. The amount of particulate material present in the upper region may in turn be controlled by controlling the particulate material entrained from the lower region to the upper region. The temperature is also preferably controlled within a range to permit sulfur capture by sorbent particles so that emissions of N.sub.2 O, NO.sub.

Abstract: A staged fluidized-bed combustion and filter system for substantially reducing the quantity of waste through the complete combustion into ash-type solids and gaseous products. The device has two fluidized-bed portions, the first primarily as a combustor/pyrolyzer bed, and the second as a combustor/filter bed. The two portions each have internal baffles to define stages so that material moving therein as fluidized beds travel in an extended route through those stages. Fluidization and movement is achieved by the introduction of gases into each stage through a directional nozzle. Gases produced in the combustor/pyrolyzer bed are permitted to travel into corresponding stages of the combustor/filter bed through screen filters that permit gas flow but inhibit solids flow. Any catalyst used in the combustor/filter bed is recycled. The two beds share a common wall to minimize total volume of the system. A slightly modified embodiment can be used for hot gas desulfurization and sorbent regeneration.