Abstract: A combustion apparatus has a fuel feed unit, a blower for supplying combustion air, a mixing unit of fuel and combustion air, a first catalyst provided downstream of the mixing unit, a first heat receiving unit adjacent to the first catalyst, a second catalyst with a large geometrical surface area than that of the first catalyst provided downstream in the flow direction of the first catalyst, an electric heater for heating the catalyst provided downstream of the second catalyst, an air permeable insulator provided downstream of the electric heater, and a second heat receiving unit provided downstream of the air permeable insulator, wherein power is supplied to the electric heater when starting combustion to heat the second catalyst over the reaction temperature of catalyst, a mixed gas of fuel and air is fed to start catalytic combustion of second catalyst, the downstream portion in flow direction of the first catalyst is heated over the reaction temperature of catalyst by the combustion heat of the second ca

Abstract: A catalytic combustion process for at least one fuel comprises the use of a plurality of successive catalytic zones, the process being characterized in that at least one of the first catalytic zones includes a catalyst comprising a monolithic substrate, a porous support based on a refractory inorganic oxide and an active phase constituted by cerium, iron and optionally zirconium, also at least one metal selected from the group formed by palladium and platinum; and in that at least one of the subsequent catalytic zones includes an active phase comprising: an oxide of at least one element A with valency X selected from the group formed by barium, strontium and rare-earths; at least one element B with valency Y selected from the group formed by Mn, Co and Fe; and at least one element C selected from the group formed by Mg and Zn, and aluminium; the oxide may have formula A.sub.1-x B.sub.y C.sub.z Al.sub.12-y-z O.sub.19-.delta., x being 0 to 0.25, y being 0.5 to 3; and z being 0.

Abstract: A combustor method and apparatus is provided. The method utilizes flameless combustion with one or more of three improvements to enhance ignition of the flameless combustor. A catalytic surface can be provided within a combustion chamber to provide flameless combustion at least in the vicinity of the catalytic surface at a temperature that is much lower than the autoignition temperature of fuel in air without the presence of the catalytic surface. Nitrous oxide or supplemental oxygen may also be used as an oxidant either instead of air or with air to reduce ignition temperatures. Further, electrical energy can be passed through the fuel conduit, raising the temperature of the conduit to a temperature above which the fuel will ignite when combined with the oxidant.

Abstract: A low emission combustion system for use in a fuel-fired apparatus includes a fuel-fired burner (30) operative for generating a flame extending substantially axially outwardly from the outlet of the burner, a heat transfer tube (40) opposed to the outlet of the burner whereby the flame extending from said burner passes into a flame inlet section (48) of the gas flow conduit (46) of the heat transfer tube, a radiator body (50) disposed within the flame inlet section of the gas flow conduit of the heat transfer tube, and a catalytic converter (60) for oxidizing carbon monoxide to carbon dioxide. The radiator body (50) has a thermal mass sufficient to reduce peak flame temperatures in the flame inlet section to less than 2800 F. The catalytic converter is disposed within the gas flow conduit at a location downstream of the radiator body.

Abstract: A device for oxidizing a gas mixture that includes at least one hydrocarbon and oxygen. The device contains a porous solid that consists of zirconia. At least one metal having a catalytic oxidation activity, for example platinum or palladium, is deposited on the solid support. The device also contains an induced-air catalytic burner for the catalytic combustion of gaseous hydrocarbon mixed with atmospheric air and a member for dissipating the heat generated within the solid support. The device develops an average thermal power of at least 10 W/cm.sup.2 and an average temperature within the support of at least 700.degree. C.

Abstract: A gas burner produces a homogeneous mixture of gas and air in a short mixing zone by creating turbulence to promote thorough mixing. The burner includes a burner housing supporting a gas distribution tube and an air blower, the distribution tube emitting jets of gas in a radial direction and supporting a baffle plate having a plurality of openings. Air from the blower impinges on the jets of gas to form streams of gas and air that pass through the openings in the baffle plate. A diffuser ring is disposed downstream from the baffle plate and extends radially inward to form a flow constriction. The streams of gas and air contact the diffuser ring and undergo turbulence and the resulting mixture of gas and air passes through the diffuser ring and expands within the interior of a perforated combustion head. The mixture passes through the perforations and when ignited obtains combustion of nearly 100% of the gas and produces a very even flame profile.

Abstract: A regenerative thermal oxidizer in which contaminated air is first passed through a hot heat-exchange bed and into a communicating high temperature oxidation (combustion) chamber, and then through a relatively cool second heat exchange bed. The apparatus includes a number of internally insulated, ceramic filled heat recovery columns topped by an internally insulated combustion chamber. From the combustion chamber, the air flows vertically downward through another column containing heat exchange media, thereby storing heat in the media for use in a subsequent inlet cycle when the flow control valves reverse. Temperature is sensed within the bed of heat exchange media in order to monitor the temperature profile and control a bypass of hot combustion gases should the temperature exceed a predetermined level.

Abstract: A cylindrical fuel reforming apparatus covered with a thermal insulating layer 16 has a fuel flow passage 1 contoured by a cylindrical contour wall 2 in its central axial direction, and a reforming catalyst bed 3 is disposed in the middle of the flow passage for reforming gas, flowing from the upstream end of the fuel flow passage 1, into a proper reformed gas. A cooling jacket 10 is arranged upstream of the reforming catalyst bed 3 so as to surround the fuel flow passage 1 and the cooling jacket is supplied with steam 11 for cooling the cylindrical contour wall 2. There are provided in the cylindrical contour wall 2 upstream of the reforming catalyst bed 3 a plurality of injection nozzles 15 for effecting communication between the cooling jacket 10 and the fuel flow passage 1 so that the steam 11 introduced into the cooling jacket 10 is allowed to flow into the fuel flow passage 1.

Abstract: Described is a process of catalytic combustion with staged fuel injection that comprises: a first injection of fuel and air, the passage of the air-fuel mixture that is formed into a catalytic zone, and a second fuel injection into the flow of output from said catalytic zone; with said process being characterized in that said catalytic zone comprises at least one catalyst that comprises a monolithic substrate, a porous support based on a refractory inorganic oxide, and an active phase that comprises cerium, iron, and optionally zirconium, as well as at least one metal that is selected from the group that is formed by palladium and platinum; the content of porous support is between 100 and 400 g per liter of catalyst; the cerium content is between 0.3 and 20% by weight relative to the porous support; the zirconium content is between 0 and 20% by weight relative to the porous support; with the iron content being between 0.01 and 3.

Abstract: The invention concerns a two-stage catalytic burner (1) with at least one feed (3) for a hydrogen or hydrocarbon-containing fuel gas and at least one feed (17) for a combustion gas such as oxygen or air, two combustion stages (15, 16), the second (16) of which is a monolithic burner through which the mixture of gases leaving the first stage (15) passes, and a heat exchanger (8) connected to the burner (1). The first combustion stage (15) is a diffusion burner in which a chamber (6) containing fuel gas is separated from the chamber (7) containing combustion gas by a catalytic layer (burner element 4) which is permeable to the fuel gas. The burner element (4) is made of highly porous catalytically active material with a porosity of >50% and pore size of 0.001 to 100 .mu.m and has a thickness of 0.05 to 10 mm. The fuel gas is fed into chamber (6) and the combustion gas into chamber (7).

Abstract: The present invention relates to a catalytic combustion system comprising a casing (1) having an inlet (2) for an oxidizer such as air, several fuel injection means (3, 5; 7) intended for a multistage fuel injection, and at least a first monolithic element (4) that may be covered with a combustion catalyst and situated downstream from a first fuel injection means (3) in relation to the direction of progress of an air-fuel mixture in the system, said first injection means performing a partial fuel injection, and comprising at least a second monolithic element (6) situated downstream from a second injection means (5), said second monolithic element (6) being intended to stabilize the combustion. The second monolithic element (6) can be covered with a combustion catalyst.

Abstract: The distribution-pressurized natural gas is supplied via a conduit arranged in the piston of an electrovalve in a nozzle of which the outlet leads to a cone which provides, with the nozzle, a ring-shaped opening which, connected to the atmosphere, acts as a secondary nozzle for injecting air into the gas flow. The cone is followed by a cylindrical element then by an abrupt widening section which opens into a heat exchanger which is in contact with a substrate impregnated with a catalytic material which oxidizes fuel gas. A small amount of air is sucked up by the widening and mixed with the gas. This mixture is then treated in the exchanger up to the transformation temperature of the sulphur-containing compound and the sulphur is then oxidized.

Abstract: The method of combusting lean fuel-air mixtures comprising the steps of:a. obtaining a gaseous admixture of fuel and air, said admixture having an adiabatic flame temperature below a temperature which would result in any substantial formation of nitrogen oxides but above about 800.degree. Kelvin,b. contacting at least a portion of said admixture with a catalytic surface and producing reaction products,c. passing said reaction products to a thermal reaction chamber, thereby igniting and stabilizing combustion in said thermal reaction chamber.

Abstract: The method of combusting lean fuel-air mixtures comprising the steps of:a. obtaining an admixture of fuel and air, said admixture having an adiabatic flame above about 900.degree. Kelvin;b. passing least a portion of said admixture into contact with one or more mesolith combustion catalysts operating at a temperature below the adiabatic flame temperature of said admixture thereby producing reaction products of incomplete combustion; andc. passing said reaction products to a thermal reaction chamber;thereby igniting and stabilizing combustion in said thermal reaction chamber.

Abstract: The conventional gas turbine combustor is improved by mounting a pilot flame producing torch in a wall of the combustor to project a flame into the combustor as a means of ignition. The torch preferably is a catalytic igniter which will operate over a wide range of air/fuel ratios.

Abstract: The method of combusting lean fuel-air mixtures comprising the steps of:a. obtaining a gaseous admixture of fuel and air, said admixture having an adiabatic flame temperature below a temperature which would result in any substantial formation of nitrogen oxides but above about 800.degree. Kelvin,b. contacting at least a portion of said admixture with a catalytic surface and producing reaction products,c. passing said reaction products to a thermal reaction chamber, thereby igniting and stabilizing combustion in said thermal reaction chamber.

Abstract: A multilayer matrix burner which has exceptionally low NO.sub.x emissions can be operated over a broad turndown range. The burner is, in effect, a three-dimensional matrix of spaced apart emissive layers. There is a first three-dimensional porous layer which acts to distribute a fuel/air mixture. There is a wider gap (which may be adjustable) between the distributive layer and one or more two-dimensional porous emissive layers. An exemplary emissive layer is a refractory wire screen. Preferably, there are multiple such emissive layers with a narrower gap between successive layers. Preferably, the porosity increases in each successive layer downstream from the preceding layer. This arrangement provides a stable flame wherein most of the combustion occurs adjacent to successive incandescent emissive layers. Preferably the successive layers in the downstream direction have a large open area for transmitting radiant energy from preceding emissive layers. Such high intensity burners, e.g. 1,500,000 BTU/h.multidot.

Abstract: A gas premix burner in which gas and air are mixed in a suction region of an impeller to form a combustion mixture. The impeller is associated with a blower housing and an electronic control circuit board, all of which are arranged upstream in a blower chamber having at least one time separating wall. The arrangement prevents the gas and the combustion mixture from reaching the motor landings or the primed circuit board.

Abstract: A premix burner has a mixing plenum, a mesh flametrap and a ceramic honeycomb arranged in series. The mixing plenum has inner and outer chambers, with a mixing nozzle for introducing a gaseous fuel concentrically located in the inner chamber. The burner is operated with either high excess air or flue gas recirculation to produce a low temperature flame at a flame face defined by the honeycomb. The thorough premixing of air and fuel ensures a flame with homogeneous air-to-fuel ratios across the flame face, producing low NOx levels. The honeycomb and flametrap also function as flame arrestors to prevent burner flashback. A method for attaining a low temperature, low NOx flame using excess air, with or without flue gas recirculation, is also disclosed.

Abstract: A single bed thermal oxidizer for oxidizing a contaminate in a gas (air) stream has a plenum above the bed containing burners for gaseous fuel and means for injecting excess air. The burners are activated to initially heat the adjacent top bed portion. The burners are then turned off and a mixture of gaseous fuel and air is passed down into and through the bed which oxidizes the gaseous fuel and transfers the hot portion of the bed downward to preheat the central region of the bed. At that point, the gaseous fuel is terminated and the contaminated gas stream is introduced into the preheated bed for oxidation of the contaminate.

Abstract: A burner structure and a method of operating a burner to reduce the pollutant emissions produced thereby are disclosed. Air and gas are premixed in a manner such that a substantially homogeneous mixture containing excess combustion air results. The velocity of the substantially homogeneous mixture is increased as it passes through the burner causing the "residence time" associated with the formation of the flame to be decreased, i.e., the combustion gases are in the reaction zone of the flame for a significantly shorter period of time, reducing the production of NO.sub.x. In order to prevent the flame from "lifting-off" the burner because of the high velocity of the substantially homogeneous air/gas mixture, flame stabilizing devices and/or a burner structure which provides flame stabilization are utilized resulting in the production of a high heat flux and low pollutant emissions.

Abstract: A method and apparatus for low NO.sub.x combustion in natural draft combustion chambers comprising staged-air combustion apparatus and process in which a fuel-rich, fuel/air mixture is introduced through a burner into a combustion chamber, forming a fuel-rich primary combustion zone flame. The fuel-rich primary combustion zone flame is attached to a flame guide disposed substantially parallel to the longitudinal axis of the primary combustion zone flame and extending from behind the burner. The flame guide also provides for removal of heat from the primary combustion zone flame. Secondary combustion air is introduced into the combustion chamber downstream of the burner to complete combustion of the fuel-rich primary combustion zone flame products. Internal recirculation of combustion gases within the combustion chamber into the fuel-rich primary combustion zone flame stabilize the fuel-rich primary combustion zone flame and contribute to emissions reduction.

Abstract: A high intensity and high efficiency radiant gas burner (10) has a housing (8), a gas inlet (11) for receiving a combustible gas, a gas injection plate (13) for distributing the gas, a gas distribution chamber (16) for permitting the gas to expand, a porous ceramic layer (17) for receiving the gas from the gas distribution chamber (16), and a plurality of elongated flame support rods (23) situated over and spaced from a burner surface (17b) of the porous ceramic layer (17). When the gas is ignited, the flame transfers energy via convective heat transfer to the rods (23). When the rods (23) heat up, they radiate energy back towards the burner surface (17b) and also outwardly away from the burner surface (17b) so that radiation intensity and efficiency are optimized. A rod adjustment mechanism (84) may be disposed on the burner (10) for moving the rods (23) to thereby optimize radiation intensity and efficiency.

Abstract: Gas phase combustion producing lower emissions in gas turbines is stabilized in a lean pre-mixed combustor, by flow of the fuel/air mixture through a catalyst which is heated by contact with recirculated, partially reacted combustion gases.

Abstract: Apparatuses for treating gas streams containing variations in VOC concentration whereby the VOC's are destroyed in a combination non-catalytic/catalytic oxidation system are disclosed. A non-catalytic destruction matrix composed of inert ceramic materials that enhance process mixing and provide thermal inertia for process stability is used when VOC concentrations are high and a catalytic oxidizer is principally used when VOC concentrations are low. The exhaust from the non-catalytic destruction matrix is passed through the catalytic oxidizer to maintain proper catalytic oxidizer operating temperatures. Supplemental fuel and air are added as appropriate upstream or downstream of the non-catalytic oxidizer to maintain proper heat values in each portion of the system.

Abstract: A porous, ceramic member defines both the burner and baffle. Gaseous fuel is supplied under pressure into a chamber and flows through the ceramic member and, in flowing, causes the aspiration of atmospheric air into the flowing gaseous fuel. The air-fuel mixture is ignited a short distance downstream of the chamber and the flame flows through the ceramic member and emerges from the ceramic member within the heat exchanger. The air mixing with the gaseous fuel causes turbulence and mixing of the gas and cools the flame prior to its reaching temperatures associated with the generation of thermal NO.sub.x.

Abstract: A gas burner is described, provided with a connection for supplying a mixture of combustible gas and combustion air, and a burner pack comprising a plurality of stacks of at least one metal plate which is deformed transversely to its flat plane, and at least one flat metal plate on both sides of each deformed plate, which stacks of burner plates are separated by a solid filler and said plates with their main surfaces being parallel to the flow direction of the gas/air mixture, wherein per stack the flow direction of the gas/air mixture from the flow channels bounded by said deformed plate and said flat plates is the same.According to the invention, each stack of burner plates comprises two or more deformed plates.

Abstract: The disposal of troublesome substances, especially global-warming halogenated compounds is difficult enough, but is particularly difficult when associated with particulate-forming matter, such as silane and arsine commonly encountered in waste gas streams of the semiconductor industry. The combustive destruction of the troublesome substances in such a waste gas stream is simply and successfully achieved by injecting the stream admixed with fuel gas into a combustion zone surrounded by the radiant surface of a foraminous gas burner that is separately fed fuel gas and excess air sufficient to burn all the combustibles entering the combustion zone. A simple apparatus integrates the combustion zone with a quenching zone for the combustion product stream.

Abstract: The method of combusting lean fuel-air mixtures comprising the steps of:a. obtaining an admixture of fuel and air, said admixture having an adiabatic flame above about 900.degree. Kelvin;b. passing least a portion of said admixture into contact with one or more mesolith combustion catalysts operating at a temperature below the adiabatic flame temperature of said admixture thereby producing reaction products of incomplete combustion; andc. passing said reaction products to a thermal reaction chamber;thereby igniting and stabilizing combustion in said thermal reaction chamber.

Abstract: The method of combusting lean fuel-air mixtures comprising the steps of:a. obtaining a gaseous admixture of fuel and air, said admixture having an adiabatic flame temperature below a temperature which would result in any substantial formation of nitrogen oxides but above about 800.degree. Kelvin,b. contacting at least a portion of said admixture with a catalytic surface and producing reaction products,c. passing said reaction products to a thermal reaction chamber, thereby igniting and stabilizing combustion in said thermal reaction chamber.

Abstract: A metal body for the gas burner of an infrared radiant heater appliance, the body (1) being generally elongate in shape having an open front that receives a plate (25) for generating infrared radiation and itself being made up of two sheet metal parts (2, 3) that are cut out, stamped, folded, and assembled together. The parts comprise: a U-shaped back part (2) having an elongate main face (4) with a longitudinally elongate depression (5) shaped to form half of a tubular Venturi shape; and a dish-shaped front part (3) with an elongate bottom to the dish-shape that presents a longitudinally elongate depression (18) shaped to constitute half of a tubular Venturi, a portion of the bottom of the dish-shape situated beyond the outlet from the Venturi being cut out and folded towards the inside of the dish-shape so as to define an opening (23) through which the gas mixture passes into the dish-shape, said portion constituting a deflector (21) suitable for distributing the gas mixture inside the dish-shape.

Abstract: An infrared ray emitter with catalytic burner including a box having an opening covered by a catalytic structure and wherein a supply of combustion gas is applied adjacent the catalytic structure and a supply of recirculating gas is introduced into the box by a fan driven by a motor which extends exteriorly from a furnace in which the emitter is mounted. Brackets are provided to mount the box within a furnace in such a manner that the emitter may be angularly adjusted with respect to the support brackets.

Abstract: A combustion catalyst is disclosed which is composed of a durable support containing a plurality of mutually partitioned and independent combustion gas flow paths and an active catalyst formed mainly of palladium and/or palladium oxide and deposited in the form of a coating on the inner wall surfaces of the combustion gas flow paths and characterized in that the deposition of the active catalyst in the form of a coating on all the inner wall surfaces is omitted in part of the whole of the combustion gas flow paths. The mutually partitioned and independent combustion gas flow paths which are provided for the durable support jointly form an aggregate of opening parts in the pattern of gratings and these opening parts have a square, rectangular, triangular, or hexagonal cross section. Thus, the durable support constitutes a so-called honeycomb structure.

Abstract: In a method of operating a low-pollution premixing burner (2) stabilized by means of vortex breakdown, in particular a burner of the double-cone type of construction, with gaseous fuels (4, 10), the main fuel gas (4) being fed to the burner (2) via a main gas tube (3) connected in one piece to the burner (2) and the pilot gas (10) being fed to the burner (2) near the axis of the latter via a separate feed line (9) by means of an exchangeably inserted fuel lance (8), and the pilot gas (10) being mixed inside the fuel lance (8) with air (17) fed from a plenum (16) outside the burner hood (6), the pilot-gas/air mixture (25) is fed to a catalyzer (21) arranged inside the fuel lance (8) at the tip of the burner (2) and is ignited and burnt there. The hot gas flow is then mixed with the colder main burner flow in the burner interior space (14).

Abstract: A combustion device (1) incorporated in an apparatus for combustion and/or decomposition of pollutants in air or other gases. The device has a stationary bed of e.g. sand having heat-accumulating and heat-exchanging properties. The bed is provided with heating means to heat a central part of the bed to the self-decomposition and/or the self-combustion temperature of the medium to be treated. The stationary bed (2) is placed on an essentially horizontal support (3), and at the remaining sides it is enclosed by side elements (4, 5) and a roof element (6), the latter resting directly on the upper face of the bed (2) so that the bed supports the roof element (6) and the loads to which the latter is exposed. Inside the bed upper, essentially horizontal tubes (7) are arranged as well as lower, essentially horizontal tubes (8), all said tubes being provided with valve systems at their ends.

Abstract: A combustor for supporting the catalytic combustion of a gaseous carbonaceous fuel/air combustion mixture contains a catalyst zone in which is disposed a catalyst body comprising at least a first and a second catalyst member and further contains a downstream zone where homogeneous combustion occurs. Each catalyst member is comprised of a carrier body having a catalyst material deposited thereon. The first carrier is made of a silica-magnesia-alumina material comprised primarily of cordierite, mullite and corundum and the second carrier is made of a ceramic fiber matrix material comprising ceramic (alumina-boron oxide-silica) fibers in a silicon carbide matrix.

Abstract: A safety device for preventing uncontrolled burning in wick-fed liquid fuel burners employs a thermal barrier between the heat of the combustion process and a removable fuel tank 60. Also, a fuel containment compartment (24) and fuel containment sump (44) are provided to receive fuel from the fuel chamber (40) when excess fuel is delivered to the fuel chamber from the removable fuel tank. When the fuel in the fuel chamber exceeds a predetermined level, a warning gauge needle 90 is deflected, alerting the user of the liquid fuel burner to a dangerous condition.

Abstract: A system for providing heated fluidized bed gasification of a residual waste liquor provides a bed of granular material and a source of liquor provided to the material bed. An injector is situated in the material bed and communicates with an air source, a fuel source and a steam source. Fuel and air are combusted in the injector and mixed with the steam which forms a combustion product and steam mixture which is in turn injected into the material bed. The combustion and mixing is separated from the bed material by being confined within the injector. The injector is a bubble cap having at least one hole or an injector made of a porous ceramic material.

Abstract: An apparatus and method for the monitoring and abatement of fugitive VOC emissions is disclosed. Suction, generated by a fume pump or a venturi type ejector, pulls air and VOC's from one or more sources of VOC emissions such as the mechanical seals of pumps or compressors. These VOC fumes are collected, separated from any liquids in a knock-out pot, and directed to a flameless combustor/thermal oxidizer comprising a tube packed with heat resistant material and surrounded by an electric heater and thermal insulation. This matrix bed of heat resistant materials is heated to a temperature sufficient to oxidize/destroy the VOC emissions. Thereafter, an optional convective quench section may be used to lower the temperature of the exhaust gases prior to their release to the atmosphere. By monitoring the temperature and/or the amount of power needed, changes in VOC emissions can be detected.

Abstract: A burner with a housing enclosing a combustion chamber and with an inlet for a gas/air fuel mixture and an outlet for combustion gas is disclosed. The combustion chamber is filled with a porous material whose porosity varies along the combustion chamber in such a way that the pore size increases in the direction of flow of the gas/air mixture so that a critical Peclet number for the pore size and accordingly for flame development results at a boundary surface or in a determined zone of the porous material, above which number a flame can develop and below which number the flame development is suppressed.

Abstract: This invention is an improved catalyst structure and its use in highly exothermic processes like catalytic combustion. This improved catalyst structure employs integral heat exchange in an array of longitudinally disposed adjacent reaction passage-ways or channels, which are either catalyst-coated or catalyst-free, wherein the configuration of the catalyst-coated channels differs from the non-catalyst channels such that, when applied in exothermic reaction processes, such as catalytic combustion, the desired reaction is promoted in the catalytic channels and substantially limited in the non-catalyst channels. The invention further comprises an improved reaction system and process for combustion of a fuel wherein catalytic combustion using a catalyst structure employing integral heat exchange, preferably the improved structures of the invention, affords a partially-combusted, gaseous product which is passed to a homogeneous combustion zone where complete combustion is promoted by means of a flameholder.

Abstract: A method and apparatus for reducing the emissions from a thermal oxidizer for volatile organic compounds (VOC) containing waste gases. The waste gas is treated in a thermal reactor and either before, in or after the thermal reactor the waste gas is contacted with a catalyzed surface device in the gas stream within the thermal oxidizer. The catalyzed surface device has a catalyzed surface which contacts the waste gas and further oxidizes the waste gas.

Abstract: This invention is both a partial combustion process in which the fuel is partially combusted using specific catalysts and catalytic structures and also a catalyst structure for use in the process. The choice of catalysts and supports solves problems in the art dealing with the stability of the overall catalyst structure and ease of catalyst operation. The catalyst structure is stable due to its comparatively low operating temperature, has a low temperature at which catalytic combustion begins, and yet is not susceptible to temperature "runaway". The combustion gas produced by the catalytic process typically is below the autocombustive temperature for the gas mixture; the gas may be used at that temperature, or fed to other combustion stages for ultimate use in a gas turbine, furnace, boiler, or the like.

Abstract: This invention is an improved catalyst structure and its use in highly exothermic processes like catalytic combustion. This improved catalyst structure employs integral heat exchange in an array of longitudinally disposed, adjacent reaction passage-ways or channels, which are either catalyst-coated or catalyst-free, wherein the configuration of the catalyst-coated channels differs from the non-catalyst channels such that, when applied in exothermic reaction processes, such as catalytic combustion, the desired reaction is promoted in the catalytic channels and substantially limited in the non-catalyst channels.

Abstract: The disposal of troublesome substances, especially global-warming halogenated compounds is difficult enough, but is particularly difficult when associated with particulate-forming matter, such as silane and arsine commonly encountered in waste gas streams of the semiconductor industry. The combustive destruction of the troublesome substances in such a waste gas stream is simply and successfully achieved by injecting the stream admixed with fuel gas into a combustion zone surrounded by the radiant surface of a foraminous gas burner that is separately fed fuel gas and excess air sufficient to burn all the combustibles entering the combustion zone. A simple apparatus integrates the combustion zone with a quenching zone for the combustion product stream.

Abstract: A catalyst member for use in processes for the catalytic combustion of gaseous carbonaceous fuels is made from a stabilized carrier having a plurality of gas flow passages extending therethrough defined by channel walls and a catalyst material disposed on the channel walls, wherein the carrier is stabilized against interaction with the catalyst material. The stabilized carrier may be prepared from a monolith comprising silica, magnesia and alumina that has a coating of alumina on the channel walls and by subjecting the coated monolith to stabilizing conditions. The stabilizing conditions may include exposure to high temperature steam.

Abstract: A circulating fluidized bed reactor includes a lower zone having a fluidization grid, primary and secondary air injection inlets, and fuel feed inlets, an upper zone, internal bubbling beds at the top of the lower zone collecting solid matter from recirculation internal to the reactor and delivering a fraction thereof to external bubbling bed heat exchangers close coupled with the walls of the reactor level with the internal beds. The external heat exchangers reject the solid matter into the lower zone after exchanging heat with an external fluid. The reactor is simple in structure and benefits from the advantages of bubbling external beds while maintaining conventional design in the lower zone.

Abstract: A porous matrix, surface combustor-fluid heating apparatus in which combustion of a fuel/oxidant mixture is carried out in stages within a stationary porous bed disposed in a combustion chamber. A fuel-rich fuel/oxidant mixture is burned within a region of the stationary porous bed disposed near the inlet end of the combustion chamber, forming a primary combustion zone. A secondary oxidant is introduced into the stationary porous bed downstream of the primary combustion zone forming a secondary combustion zone. Finally, heat resulting from the combustion is removed by fluid flowing through heat exchanger tubes embedded within the stationary porous bed.

Abstract: A catalyst bed (30) for a combustor (18) for supporting the catalytic combustion of a gaseous air/fuel (e.g., methane or natural gas) combustion mixture contains an igniter catalyst member (1) upstream of a promoter catalyst member (2). The catalyst members each comprise carrier monoliths, the igniter catalyst member (1) having an igniter catalyst material deposited thereon and the promoter catalyst member (2) having a promoter catalyst material deposited thereon. The igniter catalyst material is distinguished from the promoter catalyst material in one or more of the following ways: the igniter catalyst material may have (a) a higher catalytic activity for combustion of the air/fuel mixture, (b) a lower catalyst deactivation temperature than the promoter catalyst material, and/or (c) the promoter catalyst regeneration temperature range brackets the upper limit of the regeneration temperature range of the igniter catalyst.

Abstract: A heating unit (14) includes a flame holder (2) that has a plurality of randomly distributed pores and comprises at least about 50 wt % ceramic particles that have an emissivity of at least about 0.7. The heating unit (14) also has means for conveying a fuel/air mixture to the flame holder (2), means (18) for igniting the fuel/air mixture so it forms a flame in proximity to the flame holder, means (20) for transferring heat from the flame to a heat transfer medium, and means (26) for exhausting combustion products from the heating unit. A fuel/air mixture may be directed through the flame holder (2) and burned to form a flame in proximity to the flame holder such that the flame and flame holder interact to produce emissions of less than about 10 ng/J NO.sub.x.