Abstract: The invention relates to an afterburner for various incinerators, said afterburner (3) including a housing portion provided with a smoke delivering pipe (2) for carrying the smokes coming from an incinerator firing chamber (1) into the afterburner chamber. The chamber (3) is provided with a burner (7), for example an oil burner or a gas burner. The chamber (3) is further fitted with a smoke dispensing box (9), whereby the particles not yet incinerated are recycled back into the fling chamber (1) and the flue gases are delivered into a flue gas scrubber (12). Between the afterburner (3) and the smoke dispensing box (9) is a wall (16) including a perforated section.

Abstract: A method of incinerating wastes while controlling the production of dioxins wherein water vapor or water is sprayed in the main combustion zone of an incinerator. An apparatus for practicing the method of waste incineration, including a line for supplying main combustion air, either alone or together with a line for supplying recycled combustion gas, to the incinerator from below its hearth, is provided with a line for supplying water vapor or water in communication with the line or lines.

Abstract: A method and a system is disclosed for treating a gaseous discharge stream formed from a waste in a molten metal bath. The waste is directed into a reactor containing a molten metal bath. The molten metal bath has operating conditions which are sufficient to dissociate the waste and form a gaseous discharge stream including a dissociation product. The gaseous discharge stream is cooled in a cooling section and the dissociation product is separated, as a particulate, from a gaseous component of the gaseous discharge stream. The fluid particulate stream is recirculated to the gaseous discharge stream in a reaction section of the apparatus.

Abstract: Hot, cleansed driver fluid for a gas turbine is produced by the burning of pulverized coal, cooling of the exhaust gases resulting from burning, purifying the cooled exhaust gases and then reheating the purified gas to the appropriate level for supply to the gas turbine. The reheating of the purified gas is accomplished through heat exchange with the impure gas during the cooling step and through heat exchange with the combustion chamber in which the burning of the coal occurs.

Abstract: A method and a system is disclosed for controlling chemical reaction of a feed. The feed is directed into a reactor containing a molten metal bath to at least partially chemically react the feed to form an intermediate component. A portion of the intermediate component is combined with an off-gas which is emitted from the molten metal bath. At least a portion of the intermediate is then separated from the off-gas and returned to the molten metal bath. The returned intermediate component is then substantially converted to its atomic constituents. The atomic constituents subsequently exothermically react with other components of the molten metal bath for reaction to form compounds which are substantially stable at the operating conditions of the system, thereby allowing control of chemical reaction of the feed.

Abstract: A combustion is performed with a fuel which has been reformed by mixing with combustion products and/or water steam to supress NO.sub.x formation.

Abstract: An apparatus for purifying a pollutant-containing outgoing air from the industrial installations has a heat exchanging bed, which has a predetermined thickness, consist of a suitable, preferably mineral, material, and is located in the interior of a shaft-like reactor housing. During the purifying operation, the pollutant-containing air flows through the heat exchanging bed into a combustion chamber, and heated purified air flows from the combustion chamber through the heat exchanging bed in opposite direction, giving up its heat to the heat exchanging bed and thereby being cooled down. The pollutants contained in the pollutant-containing air are burned in the heat exchanging bed and, if needed, in the combustion chamber.

Abstract: Apparatus for cooperation with an associated furnace having the capability of burning either coal or oil wherein the improvement includes a coutant having an opening in the bottom thereof. An extended ash hopper is disposed under the coutant. The hopper includes a portion that extends beyond the coutant and a furnace sidewall that abuts an end of the coutant. The ash hopper is generally registered with respect to the opening and the apparatus includes apparatus for conducting gases to be recirculated including a recirculation fan, a duct coupling the apparatus for conducting to the ash hopper; and apparatus for sealing the portion with respect to the duct. In some forms of the invention the duct enters the laterally extending portion through the top thereof. The apparatus for sealing may include first apparatus for receiving a liquid and apparatus for sealing includes at least a first plate fixed to and depending form the coutant.

Abstract: An incinerator is described which includes a cylindrical rotary furnace slightly inclined downwardly in its longitudinal direction for combusting material introduced into an entrance, a cylindrical housing for housing the furnace and a secondary combustor connected with an exit of the furnace. Partition plates are placed in an annular space between the housing and the furnace for defining a combustion air introduction zone below the furnace and recirculated gas introduction zone above the combustion air introduction zone. A gas recirculation duct extends from the secondary combustor to the furnace housing for introducing a portion of the gas flow discharged from the secondary combustor into the recirculated gas introduction zone. An external air flow is introduced to the combustion air introduction zone. The recirculated gas lowers the,temperature of the furnace and this results in reduced NOx generation.

Abstract: A thermal conversion pyrolysis reactor system (10) is provided for use in providing a continuous flow type pyrolysis reaction for conversion of carbonizable input materials ("MW") (12). The reactor system (10) utilizes a diffusion material ("MD") (14) which is preheated and admixed with the MD (12) in order to facilitate pyrolysis and to partially catalyze reactions. Subsystems are provided to receive gaseous (30), liquid (32) and solid (32) phase outputs. The reactor system (10) includes further component subsystems for waste material MW input (22), MD input (26), reactor chamber (24), and heating (28). The MD (14) is preheated by being carried through the reactor chamber (64) prior to admixing with the MW (12) and further by exhaust gases (94) from the furnace space (88) being directed through a heat exchanger (126).

Abstract: An incineration process which can utilize any type of incineration means for disposing of hazardous, as well as non-hazardous, burnable waste. Such waste include toxic combustible liquids, oil slurries, soils contaminated with dioxin, PCBs, creosote, or any other potentially toxic combustible material. In particular, the present invention relates to an incineration process which has no continuous stack discharge of polutants. In this process, the flue gas stream from the incineration stages is enriched with oxygen and fed to a downstream combustion zone. A portion of the flue gas stream from the downstream combustion zone is enriched with oxygen and recycled to the incineration means. The remaining portion of the flue gas stream from the downstream combustion zone is scrubbed to remove acid gases and passed through a purification zone wherein any remaining contaminates are removed.

Abstract: A method of incinerating wastes while controlling the production of dioxins wherein water vapor or water is sprayed in the main combustion zone of an incinerator. An apparatus for practicing the method of waste incineration, including a line for supplying main combustion air, either alone or together with a line for supplying recycled combustion gas, to the incinerator from below its hearth, is provided with a line for supplying water vapor or water in communication with the line or lines.

Abstract: A renovated incinerator is essentially composed of a furnace, a circulation means, and an exhausting means. The circulating means picks up any particle which is unburned or not burned thoroughly and delivered to the furnace for continuous burning until all waste material become ashes which are collected and forming asbestos. A circular water tank is integrally formed surrounding the furnace to utilize steam from boiling water in the tank to generate power.

Abstract: A boiler having vertical walls of large size constituted by screens of heat exchanger tubes, fitted with a flue gas recycling circuit, and including a prismatic bottom portion referred to as an "ash box". The recycled combustion gases are fed via at least one duct that opens out into one of the end walls of a hopper disposed beneath the ash box.

Abstract: A garbage disposal system includes a garbage classifier unit, which consists of a cutting mechanism, a separation water trough, squeezers, and a blower separator, and is controlled to separate plastics and mineral from garbage; a garbage furnace controlled to burn garbage being delivered from the garbage classifier unit, a waste gas treatment unit controlled to treat exhaust gas from the garbage furnace, and a sewage treatment unit controlled to treat waste water from the garbage classifier unit and the waste gas treatment unit for a repeat use.

Abstract: Urban waste is dried and burned in a mechanical grate furnace in a reducing atmosphere to reduce the formation of NO.sub.x. Consumption of the clinker is completed in a well at the base of which a device such as a plasma torch is provided for vitrifying the clinker. The combustion gases are burned in the presence of secondary air in a circulating fluidized bed furnace. Most of the fly ash is removed from the flue gases in a filter before the gases are passed through a boiler in which they are cooled. The flue gases then pass through a conventional cleansing area from which they are evacuated by a stack. There are very low concentrations of harmful products in the flue gases and in the clinker. The fly ash collected on the exit side of the fluidized bed is recycled with the clinker to be vitrified. Heavy metals evaporated in the furnaces are recovered via a purge.

Abstract: An apparatus for recovering heat, and a flue gas recovery and/or recirculation and/or induced draft apparatus for boilers. The apparatus for recovering heat may be used in combination with the flue gas recovery and/or recirculation and/or induced draft apparatus for boilers. The flue gas recovery and/or recirculation and/or induced draft apparatus receives combustion gases from the apparatus for recovering heat and recirculates a portion of the combustion gases to a burner of a boiler and transmits the remaining portion of the combustion gases through a flue that communicates with the atmosphere.

Abstract: Methods and apparatuses for removing contaminants from materials, particularly vaporizable contaminants from flowable material such as liquids, sludges or soil: and in one aspect, reusing heat produced in the operation to vaporize contaminants from the material.

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: The disclosure is directed to a burner-containing apparatus, such as a boiler or a furnace, having reduced noxious emissions. A burner receives input air and has an exhaust for exhausting flue gases. A flue gas recirculation system is provided for recirculating a portion of the flue gases back to an input of the burner. A fogging device, which produces a fog from a fogger water supply and a fogger air supply, humidifies the recirculated flue gases.

Abstract: A technique for decontaminating material, including disposing a grid network of perforated pipes on a base, and covering the same with contaminated soil. A barrier layer is laid on the contaminated material and provided with a vent port coupled to a vapor disposal unit via a suction system. A source of heated gas is coupled to the grid system to force heated air through the contaminated soil and vaporize the contaminants. A mobile decontamination system includes an insulated container having a top lid for loading contaminated material in the container, and an insulated back door for removing decontaminated material. Apertured pipes on the container floor convey a high temperature gas to the contaminated material to vaporize the contaminants. A suction system is coupled to a vapor outlet of the container to remove vaporized contaminants.

Abstract: A closed combustion system is used to incinerate hazardous wastes and vitrify ash. An incinerator is provided with pure oxygen, hazardous waste and fuel for incinerating the hazardous waste. Slag from the incinerator is treated separately. Combusted products from the incinerator such as flue gases, liquids, solids and ash are channeled through the system and recirculated back to the incinerator for incineration. A dust collector is used to collect ash from the combusted product and recirculate back to the incinerator. A condensing heat exchanger is used to collect and dispose of waste liquids. Filters are used for filtering particulates from the combusted product. A CaO pebble bed is provided for causing reactions with the flue gases. Remaining insert gas in the system are bled into the atmosphere. Flue gases from the system are recirculated back into the pure oxygen for entry into the incinerator in order to provide temperature control.

Abstract: For the incineration of waste materials, a process is described, in which the waste materials are reduced in size as far as necessary and are subsequently optionally mixed with fuel and are incinerated at temperatures from 1000.degree. to 1700.degree. C. to form liquid ash, a major part of which is removed as liquid slag from the combustion chamber, and the pollutants are removed from the exhaust gases produced by the incineration. The process is characterized in that the pollutant-containing droplets of liquid ash which are suspended in the exhaust gas are separated at a temperature, which is close to the incineration temperature by at least one mass force separator and are subsequently either solidified alone or are combined with the liquid slag and solidified together with said slag.

Abstract: A process and equipment for pyrolyzing packaged biomedical waste in a reactive metal alloy in an oxygen deficient atmosphere and separating for recycling the resultant carbon, glass, and metal while venting resultant hydrogen and nitrogen from an aqueous off gas scrubber.

Abstract: An automatic firebox provided with a fuel hopper that delivers fuel through a pivoting funnel to a grate burning area. The grate burning area is provided with at least one pivoting fuel grate which operates automatically in sequence with the fuel feed and hopper so as to provide automatic stoking. An automatic control operated by temperature and/or time is disclosed.

Abstract: The procedure for supplying combustion air during grate firings, in which the primary combustion air is introduced into the fuel, and secondary combustion air is introduced directly into the flow of exhaust gas, and in which, in addition, some of the exhaust gas is tapped off from the flow of exhaust gas and returned to the combustion process, includes the withdrawal of exhaust gas directly above the fuel in the area where there is a large quantity of unused primary air, and the delivery of this exhaust gas that has been tapped off to the combustion air, the quantity of which is reduced according to the quantity of exhaust gas that is mixed with it.

Abstract: Oxidizable components in an exhaust air or gas flow are burnt by a burner in a combustion chamber enclosed in a housing. For this purpose the exhaust air is distributed into inlet ends of heat exchanger pipes which have outlet ends near the burner. The arrangement is such that the exhaust air carrying oxidizable components flows through the heat exchanger pipes while the exhaust air freed of oxidizable components flows around the heat exchanger pipes. In order to permit effective heat expansions and contractions of the heat exchanger pipes, these pipes have an L-configuration with radially inwardly extending legs having inlet ends connected into perforations in a jacket forming an exhaust air distribution chamber, and with substantially axially extending legs having outlet ends leading close to the burner. An air inlet leads centrally into the distribution chamber and a cleaned air outlet leads out of the housing.

Abstract: Flue gas is captured from an emissions stack and recirculated to a burner by an induced flue gas recirculation system comprising: a mixing assembly for mixing combustion air and recirculated flue gas into a substantially homogeneous mix; a burner assembly for mixing and combusting the combustible mix with a fuel to produce a flue gas; an injection assembly, connected to and downstream from the mixing assembly and connected to and upstream from the burner assembly, for receiving the combustible mix from the mixing assembly and injecting it with the combustible fuel into the burner assembly; a combustion chamber connected to and downstream of the burner assembly for containing the combustible mix and flue gas; an emissions stack connected to and downstream from the combustion chamber for venting the flue gas from the combustion chamber; recirculating means for recirculating a portion of the flue gas from the emissions stack to the mixing assembly; and a purge assembly connected to the recirculating means for re

Abstract: An emission control fluidized bed reactor is disclosed. The reactor includes a central chamber with a fluidized bed at the base of the central chamber and circulating particulate matter above the fluidized bed forming a freeboard. The fluidized bed is maintained at a temperature range between 1500.degree. F. and 1600.degree. F. The freeboard is operated in a predetermined environment between 1600.degree. F. and 1700.degree. F. and with a velocity between 4 to 12 feet per second. An externally fed gas from a discrete industrial process such as an external combustion system or a plant process is conveyed into the freeboard. The externally fed gas includes pollutants which are suppressed as a result of the predetermined environment in the freeboard.

Abstract: An incineration process which can utilize any type of incineration means for disposing of hazardous, as well as non-hazardous, burnable waste. Such waste include toxic combustible liquids, oil slurries, soils contaminated with dioxin, PCBs, creosote, or any other potentially toxic combustible material. In particular, the present invention relates to an incineration process which has no continuous stack discharge or pollution. In this process, a portion of the flue gas stream is enriched with oxygen and recycled to the incineration means. The remaining portion of the flue gas stream is scrubbed to remove acid gases and passed through a purification zone wherein any remaining contaminates are removed.

Abstract: Combustion apparatus comprises a combustion chamber for effecting primary combustion of combustible material charged thereinto, an exhaust conduit for exhaust gases emitted by the primary combustion, primary air inlet means for directing primary air into said combustion chamber, and secondary air inlet means for directing secondary air into the exhaust conduit at least in the region adjacent the combustion chamber so as to promote further combustion of said exhaust gases, said secondary air inlet means including an air distributor arranged centrally of the conduit characterized in that secondary air inlets are additional provided in the wall of the conduit over at least part of the extent of the air distributor.

Abstract: To avoid high NOx emissions, the fuel is oxidized with an extremely high exhaust gas recirculation ration substantially without flames and without pulsations.

Abstract: Apparatus (10) and a method for removing volatile organic contaminants from particulate material utilizes a particulate material processor (12) and an emissions processor (14) which includes a recirculating emissions pretreatment circuit (16) and a final treatment system (18). The recirculating emissions pretreatment circuit (16) has an inlet (72) that receives the contaminated hot gas emissions from a heating unit (20) of the material processor (12) and also has a condenser (76) that is preferably embodied by a wet scrubber (88) for removing condensible gases from the emissions prior to passage through an outlet (78) thereof back to the heating unit (20). An inlet (82) of the final treatment system (18) has a fan (48) that draws off a portion of the pretreated emissions for a final treatment. This final treatment may be provided either by a flame burner that is most preferably a part of the heating unit of the particulate material processor (12) or by a carbon adsorber (144).

Abstract: A heat recovery system is disclosed for a pulse combustion drying system in which the exhaust gas of combustion from a pulse combustor passes successively through a dryer, a product collector and a scrubber. The heat of the exhaust gas is recovered in the scrubber by spraying with water or other liquid and transferring by heat exchange the heat absorbed by the water to compressed air, and passing the heated compressed air successively through a membrane heat exchange tube on the wall of the product collector and a membrane heat exchange tube on the wall of the dryer. The air is discharged finally in an air-injection nozzle of the pulse combustor.

Abstract: A waste treatment system conditions waste materials for combustion by uniformly drying them to a predetermined moisture level and subsequently incinerating the dried materials in a burner which effects complete combustion of even high moisture content fuels. The system includes the burner, a dryer assembly, and a system of fans which clarifies vapors withdrawn from the dryer and which returns at least part of these vapors to the burner. The system mixes exhaust gasses from the burner and recycled vapors returned by the fans to produce gasses of a suitable temperature for drying the materials. The waste materials and the gasses are then introduced into the dryer, which is designed to use the gasses to dry the material uniformly to the predetermined moisture level without burning them prematurely. The dried materials are then conveyed to the burner, where they are burned to produce more exhaust gasses for drying additional materials. The residual ash in the burners is nontoxic and is suitable for burying.

Abstract: A combustion chamber for combusting a substance includes a burner and at least three successively disposed parts including a primary chamber, a secondary chamber and an ash discharge chamber. The burner is associated with and conducts a first air flow to the primary chamber. The primary chamber has an inlet for conducting a second air flow for substoichiometric combustion of a substance to be combusted at a temperature below an ash softening point and without clinker flow. The secondary chamber has an inlet for conducting a third air flow for brief, intensive, complete combustion of the substance discharged from the primary chamber with clinker flow, and the secondary chamber has walls and a material lining the walls being resistant to fluid clinker.

Abstract: A method for controlling combustion in a furnace into which combustible material, e.g., urban refuse, industrial waste, and a controlled quantity of combustion air are fed. The furnace includes a mixing/stirring region where unburnt gas and secondary combustion air are mixed and stirred. A part of exhaust gas derived from the furnace is blown into the mixing/stirring region depending on variation in the quantity of the secondary combustion air, and a flow rate of mixture gas consists of the exhaust gas and the secondary combustion air to be fed into the mixing/stirring region is maintained within a predetermined region so that effective combustion takes place.

Abstract: A method and system for flue gas recirculation is disclosed which will minimize NOx production from hydrocarbon combustion. In the present invention a furnace having an oxygen-bearing primary source of combustion air, a mixing chamber, a combustion chamber in downstream communication with the mixing chamber and an exhaust section downstream of the combustion chamber is provided with a flue gas recirculation line. The recirculation line establishes communication between the exhaust section and the mixing chamber for the return of combustion products as a secondary source of combustion air which is relatively lean in oxygen and is combined with the primary source of combustion air in the mixing chamber. The ratio of flow rates for the primary and secondary sources of combustion air is controlled by a signal generated by a sensor which senses the oxygen concentration in the mixing chamber.

Abstract: The present invention pertains to a process and apparatus for the refinement of exhaust particulate matter from a boiler or other device burning an organic fuel such as coal. More specifically the present invention is a process or apparatus that utilizes successive size and density classifications to achieve the desired result of carbon and sorbent removal, from the exhaust particulate, for disposal and recycling purposes.

Abstract: Apparatus (10) and a method for removing volatile organic contaminants from particulate material utilizes a particulate material processor (12) and an emissions processor (14) which includes recirculating emissions pretreatment circuit (16) and a final treatment system (18). The recirculating emissions pretreatment circuit (16) has an inlet (72) that receives the contaminated hot gas emissions from a heating unit (20) of the material processor (12) and also has a condenser (76) that is preferably embodied by a wet scrubber (88) for removing condensible gases from the emissions prior to passage through an outlet (78) thereof back to the heating unit (20). An inlet (82) of the final treatment system (18) has a fan (48) that draws off a portion of the pretreated emissions for a final treatment. This final treatment may be provided either by a flame burner that is most preferably a part of the heating unit of the particulate material processor (12) or by a carbon adsorber (144).

Abstract: A method and system for flue gas recirculation is disclosed which will minimize NOx production from hydrocarbon combustion. In the present invention a furnace having an oxygen-bearing primary source of combustion air, a mixing chamber, a combustion chamber in downstream communication with the mixing chamber and an exhaust section downstream of the combustion chamber is provided with a flue gas recirculation line. The recirculation line establishes communication between the exhaust section and the mixing chamber for the return of combustion products as a secondary source of combustion air which is relatively lean in oxygen and is combined with the primary source of combustion air in the mixing chamber. The ratio of flow rates for the primary and secondary sources of combustion air is controlled by a signal generated by a sensor which senses the oxygen concentration in the mixing chamber.

Abstract: This Hazardous Waste Reclamation process pyrolyzes hazardous waste such as PCB (polychloro-biphenyl) in a closed system in a molten alloy, containing some aluminum, at a minimum of 800 degrees C. to form activated carbon that is recovered from the circulating exit gas stream and an impure alloy ingot containing unreacted metals and metal salts that are saleable to a metal processor as a high grade ore. The composition of the alloy may be varied to assure maximum reaction to nontoxic alloy salts that remain in the ingot.

Abstract: This invention is directed to an apparatus for the combustion of coal comprising a heated tubular reactor having combined air and granular coal inlet means for tangentially introducing air and granular coal into the reactor, external heating means, insulation means, and an outlet means wherein the coal is partially burned in the heated tubular reactor to a temperature 50 to 100 degrees Fahrenheit below the fusion temperature of the ash produced from the coal to be used to produce partial combustion products composed of coke, ash and combustion gases. The partially combusted products exiting from the tubular reactor are tangentially introduced with additional air into a second tubular reactor here they are completely burned.

Abstract: A hybrid combustion system is provided combining advantages of a fluidized bed combustion portion and a pulverized coal combustion portion. The former portion includes a fluidized bed chamber, a coal mill without an air separator, a recycling duct connected to the coal mill, a coal supply duct, and a spray feeder. The fluidized coal combustion portion includes a pulverizing coal mill with air separator, a blowing duct for blowing ground coal, at least one pulverized coal burner and an air recycling duct for recycling combustion air. Fluidized bed combustion takes place in a lower part of the system and pulverized coal combustion takes place above the fluidized bed combustion. Each of the portions may be independently operated of the other. A main combustion chamber is common to both the fluidized bed portion and the pulverized coal portion. A related process is also described.

Abstract: A furnace system is provided with exhaust gas recirculation via a recirculation tube having an inlet mounted downstream of the furnace firing area and an inlet disposed in juxtaposition to the blower fan wheel of the furnace blower. The recirculated gases can enter the tube from either the stack or the firebox. The inlet penetrates the air intake plenum either axially thereof or at an angle thereto through a sidewall. The furnace includes both an air intake throttle and an air intake butterfly control valve. An exhaust gas recirculation control valve can be linked to the air intake control butterfly valve for their operation in concert. The air intake throttle is either a rigid baffle or a pivotable flap.

Abstract: A device for sealing and absorbing differential expansion between a cooling chamber for cooling particles in suspension and a recycling duct comprises a tubular expansion joint part (2) interconnecting the wall (1) of the cooling chamber and the recycling duct (3), with guide plates (7) for guiding the tubular part being fixed to the outside wall of the chamber and being distributed around the tubular part and bearing thereagainst by means of rolls (8, 9), a flat gasket (6) being interposed between the ends of the tubular part and the recycling duct, and controlled clamping flanges (10, 11) being disposed on the ends and being provided with oblong holes (16, 17) for passing clamping bolts (18), one of the flanges being provided with pebble-shaped parts (20) bearing against corresponding clamping adjustment shoes (22) on the other.

Abstract: A two zone pyrolysis unit having a first drying zone and a second pyrolysis zone is provided for detoxifying heavy metals contained in sludges, soils and similar materials. A condenser and an afterburner are in flow communication with the first and second zones respectively.

Abstract: A process for heat-treating refuse comprising the steps of decomposing in a combustion furnace a quantity of refuse into slag, emitted gas and fly dust. The fly dust is separated into a fine dust fraction and a coarse dust fraction. The coarse dust fraction is fed back to the combustion chamber, and the fine dust fraction is treated for removal of desired constituents.

Abstract: To make it possible to burn brown coals with cinders that vary in composition in the fluidized bed (6) of one and the same steam generator, one of the flue surfaces (12 or 13) accommodated in flues (2 and 3) downstream of the bed is exploited by way of communicating lines (43, 44, and 45), which can be blocked off, as either economizers or superheaters as desired. The economizer mode is employed when a prescribed volume of flue gas is recirculated through a recirculation line (29) to maintain a fuel-type dictated low bed temperature of preferably 730.degree. to 760.degree. C. The superheater mode is employed when less flue gas is recirculated to maintain a fuel-type dictated higher bed temperature of preferably 820.degree. to 805.degree. C.

Abstract: An improved burner head for a forced air furnace is disclosed which includes a burner tube fitted with gas nozzles, air flow openings, and a flame tube. At least one radial opening is provided between the end of the burner tube and an end of the flame to allow exhaust gas recirculation via a ribbed ring secured between the burner tube and the flame tube upstream of the radial opening but downstream of the gas nozzles and airflow openings. The ribbed ring includes ribs protruding radially inward crosswise to the longitudinal axis of the burner head. The burner head allows for a substantial reduction in NOx, to a level on the order of less than 50 ppm.