Abstract: A fluidized bed combustor is provided with a multistage arrangement of vortex generators in the freeboard area. The vortex generators are provided by nozzle means which extend into the interior of the freeboard for forming vortices within the freeboard area to enhance the combustion of particulate material entrained in product gases ascending into the freeboard from the fluidized bed. Each of the nozzles are radially inwardly spaced from the combustor walls defining the freeboard to provide for the formation of an essentially vortex-free, vertically extending annulus about the vortices whereby the particulate material centrifuged from the vortices against the inner walls of the combustor is returned through the annulus to the fluidized bed.

Abstract: Improved combustion of liquid fuel is achieved with a porous fiber burner by forming a mixture of the vaporized fuel and all of the desired combustion air sufficiently heated to prevent condensation of the vaporized fuel, and introducing the heated mixture into the porous fiber burner to effect flameless combustion on the outer surface of the burner. The resulting surface combustion produces a high proportion of radiant heat and increased thermal efficiency while suppressing the formation of nitrogen oxides and other pollutants in the flue gas. Periodically, fuel gas may be supplied to the same porous fiber burner.

Abstract: A fluidized bed reactor in which an air distribution plate is disposed within an enclosure for supporting a bed of particulate material including fuel. The air distribution plate includes a plurality of vertically disposed nozzles extending therethrough for receiving air from an air plenum and discharging the air in an upward direction into the bed at a velocity sufficient to fluidize the bed material and support the combustion or gasification of the fuel. A first pressure sensing device is disposed within at least one of said nozzles and a second pressure sensing device is disposed within the air plenum, whereby the rate of air flow into the bed of particulate material can be measured.

Abstract: A ceramic burner for a hot blast stove, having a burner head where the combustion components mix and an air duct and a gas duct beneath the head for conducting combustion components to the head, the gas duct is within the air duct and is bounded by a wall. To prevent stresses due to differences of thermal expansion at least one horizontal sliding joint is arranged in the bounding wall of the gas duct closely under the burner head. The air duct is bounded by a brickwork wall which continues upwardly past the burner head and forms a combustion chamber. The burner head projects over and is supported by a shoulder in this wall and an essentially vertical expansion joint is located between the burner head and the wall.

Abstract: A fuel burning power plant comprises a bed vessel with a bottom grate which divides the bed vessel into an upper combustion chamber and a lower part with at least one ash chamber. The bed grate consists of parallel air distribution tubes each with air nozzles, between which tubes gaps are provided where bed material may pass from the combustion chamber down to the ash chamber. Below the tubes there is a transverse air distribution chamber. The tubes are connected in groups to the air distribution chamber by a double-walled sleeve extending down from the tubes.

Abstract: A high efficiency, high temperature radiant heating system utilizing regeneratively coupled combustors. The combustor/regenerator units each comprise a porous body with combustion supported in one layered zone and regeneration occurring in an adjacent layered zone in a subsequent cycle. Each combustor/regenerator unit cycles between combustion and regeneration operational modes and is gas flow coupled with a similar unit operating simultaneously in a mode opposite that of the former. Heat in the combustion products produced at one combustor/regenerator unit is received at the regenerator zone of the other coupled unit and vice versa.

Abstract: In a fluidized bed reactor, nozzles are provided for distributing fluidizing gas from a windbox into the reactor while preventing the backflow of solid particles through the nozzle into the windbox. The nozzle defines an upper part of high heat and wear resistant material adapted to contact the mass of particles. At least one opening is defined in each nozzle through which fluidizing gas passes between the upper part and the windbox, and a solid, though porous, material abuts or defines the opening for allowing the passage of gas while preventing passage of solid particles. The nozzle may comprise a stand pipe having a sintered metal portion disposed below the upper part. Other constructions provide the solid mass as a metal wire mesh acid proof filter, or as a porous ceramic material, or as a high temperature ceramic material. The solid mass may have pores with a pore size of between about 50-1,000 micormeters.

Abstract: According to the invention, a combustion apparatus includes an upright type combustion chamber having a bottom, conduit means extending below and along the bottom of the combustion chamber and having a nozzle which passes upwardly through the bottom and opens into the combustion chamber, a ringed body supported in the combustion chamber with a gap formed between the lower edge of the ringed body and the bottom of the combustion chamber, air blasted from the nozzle passing through the ringed body, a heating medium contained in the combustion chamber. Particles of the heating medium blasted by the action of the nozzle from the lower part of the ringed body are circulated through the inner bore of the ringed body.

Abstract: A fluidized bed combustor wherein a combustion chamber and a regeneration chamber are both contained in a single hollow body is provided. These two chambers are formed by vertically partitioning the body by a partition wall, which has an upper opening and a lower one, and also each have a perforated plate at the bottom part thereof on which a heat transfer medium containing a desulfurizing agent is placed and fluidized. The desulfurizing agent is transferred from the combustion chamber through the lower opening to the regeneration chamber and circulated by overflow through the upper opening again to the combustion chamber. Various modifications of the above-mentioned fundamental embodiment are proposed. Combustion and desulfurization are automatically and effectively carried out in a single apparatus to give a high percentage desulfurization, make the apparatus compact, and reduce the initial cost and the running cost thereof.

Abstract: A process and apparatus for high temperature combustion in a combustion chamber comprising two opposed porous plates is provided whereby increased combustion temperatures are achievable by means of internal radiant energy recuperation. The high temperature combustion apparatus and process may achieve super-adiabatic combustion temperatures and is especially suitable for applications such as waste disposal and incineration.

Abstract: A fluid bed combustor comprising a generally rectangular housing defining a freeboard space. A plurality of vertically spaced and horizontally staggered beds are provided in the housing and extend inwardly into the space from a rear wall and from a front wall of the housing. A serpentine flue gas path is defined between the staggered beds. Each bed is supplied with combustion air and fluidizable fuel with the freeboard space of each bed including gases from that bed plus gases from all previous beds in the flue gas path. In this way an increased residence time is established without substantially increasing the dimensions of the combustor. A simplified recycle system can also be provided since materials from each bed cascade down into a lower bed so that all materials are eventually accumulated in the lowest beds from which they can be removed.

Abstract: The invention relates to a method for decreasing emissions of nitrogen oxides and sulfur oxides when burning fuel which contains nitrogen and sulfur. According to the invention this is carried out by feeding fuel (4) and oxygen-containing gas (5) into a combustion reactor (1) the temperature of which is preferably 900.degree.-1500.degree. C., and that the combustion gases formed are directed into a suspension reactor (2) the temperature of which is preferably 750-1050.degree. C. and into which a pulverous material which binds sulfur oxides is fed so that the suspension density is 1-200 kg/m.sup.3, the oxygen concentration in the combustion reactor (1) and the suspension reactor (2) being controlled so that their total air coefficient is about 0.

Abstract: An improved reinjection system is described for a bubbling bed fluidized bed combustor of the type having a combustion zone in which fuel is burned in a fluidized bed of granular material, means for collecting particles from the flue gases and means for reinjecting the collected particles into the combustion zone. The improved reinjection system comprises a first particulate material conductor pipe sloping downwardly toward the combustion zone, the lower end of this first downwardly sloping pipe being flow connected by way of a lower corner or elbow to a short section of upwardly sloping pipe. The upper end of this short upwardly sloping pipe is flow connected by way of an upper corner or elbow to a second downwardly sloping pipe. The first downwardly sloping pipe, the upwardly sloping pipe and the second downwardly sloping pipe form therebetween a Z-valve.

Abstract: A combustion plant includes a circulating fluid bed, which is maintained by the supply of fuel, inert material and oxygen-containing fluidizing gas to a vertical furnace shaft. This is, at its upper end provided with an outlet for combustion gases and bed materials, which is separated from gas in a separating means, and by way of a lock is returned to the furnace shaft. The separating means is of a mechanical type, and located vertically above a further vertical shaft communicating with the lock. The further shaft encloses distribution means for the particles and a heat exchanger for cooling the particles falling from the gas stream, before they are re-introduced into the furnace shaft by way of the lock.

Abstract: A means and method of controlling the load turn-down in a fluidized bed combustor including a fluidized combustion bed having an independent fluidization air source. A separately fluidizable heat transfer bed surrounds the fluidized combustion bed. By independently adjusting the fluidization of the heat transfer bed, the load turn-down of the fluidized bed combustor can be accurately and efficiently controlled.In an alternative embodiment, one or more heat transfer beds are positioned in and surrounded by the combustion bed. Conduits are then positioned within the heat transfer beds to carry a circulating and heat-conducting medium therethrough.

Abstract: A method and system for controlling the cyclone collection efficiency and recycle rate in a fluidized bed reactor in which air is introduced into the cyclone separator in a direction opposite to that of the flow of the flue gases and entrained solids. The air entrains a portion of the fine solids and passes same through the separator and to a heat recovery area to reduce the solid inventory reduction as needed.

Abstract: An air supply nozzle for a fluid bed furnace comprises a tubular member attachable to a plate, forming the bottom of the furnace. The tubular member is upwardly closed by a lid and just below the same a number of air dispersing openings are provided. A wear-resisting ring of hard metal is attached to the upper end of the tubular member and has a thickness and a height noticeably exceeding the wall thickness of the tubular member. The void within the ring is filled with refractory concrete so a dome projecting above the ring is formed. The tubular member includes a un-perforated portion, which has such an extension that the tubular member, after a hard wear, may be cut, a lower stub of the tubular member remaining at the plate, while the top is substituted by a new portion. The two portions of the reconditioned tubular member are then connected by an internal supporting sleeve and tack welding.

Abstract: The bed depth in a power plant burning sulfur-containing fuel in a fluidized bed of material which constitutes a sulfur absorbent in a combustion chamber is controlled on the basis of plant power output. A plurality of sensors connected to the combustion chamber determine the existing bed depth. A bed material mill grinds material removed from the bed prior to returning it to the bed, the rate at which the mill operates being controlled by the extent to which the actual bed depth differs from the desired bed depth. The mill grinds some bed material to small enough size for it to be carried from the combustion chamber with the combustion gases.

Abstract: A means and method of controlling the load turndown in a fluidized bed combustor including a fluidized combustion bed having an independent fluidization air source. A separately fluidizable heat transfer bed surrounds the fluidized combustion bed. By independently adjusting the fluidization of the heat transfer bed, the load turndown of the fluidized bed combustor can be accurately and efficiently controlled.

Abstract: A fluidized bed reactor and a method of operating same in which a bed of particulate material is supported on a grate in an enclosure. Air is passed through the grate to fluidize the particulate material and promote the combustion of the fuel. At least one separating unit is disposed adjacent each of two walls forming the enclosure for receiving the mixture of air, the gaseous products of combustion and the relative fine particulate material entrained by the air and gaseous products of combustion. Each separating unit operates to separate the particulate material from the mixture, and a distributor unit is associated with each separating unit for receiving the separated particulate material and distributing it to the bed at multiple locations.

Abstract: A pressurized fluidized bed burner with a pressurized container. The container is provided with an air-supply connection and accommodates a combustion chamber. The combustion chamber is provided with an air box to supply combustion air. A compressor and a preliminary air heater are accommodated in the air line leading to the pressurized container. The object is to exploit lost heat to heat the combustion air and to prevent the wall of the pressurized container from being exposed to additional thermal stress. The pressurized container has an air-extraction connection. The intake end of the preliminary air heater communicates with the air-extraction connection. Its outlet end communicates with the air box in the combustion chamber through an air line that extends through the pressurized container.

Abstract: The invention relates to a circulating fluidized bed reactor comprising a particle separator (9) having a horizontal vortex chamber (23). The separator is preferably disposed on top of the combustion chamber (5). The pipes (25) discharging gas from the vortex chamber have been connected to openings (24) disposed on the periphery (19) of the vortex chamber.

Abstract: A cast air nozzle is adapted to be mounted on the bottom of a combustor, particularly a fluidized-bed combustor. The air nozzle comprises a substantially gun-shaped body having a substantially horizontal upper part with a front portion and a rear portion, and a substantially vertical lower part with a through, substantially vertical inlet duct, two substantially horizontal outlet ducts in the upper part extending from the upper end of the inlet duct and opening at the front end of the front portion. The outlet ducts diverge towards the front end of the front portion, whereby an air current flowing through the air nozzle is caused to leave the nozzle in the form of horizontal diverging air jets. The upper part has at the front portion a horizontal planar upper surface and at the rear portion a backwardly-downwardly inclined upper surface, said surfaces forming an angle with each other, whereby the material in the combustor, which is conveyed across the air nozzle, does not collect on the upper portion.

Abstract: A fluidized bed steam generating system includes an upstanding combustion vessel, a gas/solids separator, a convection pass boiler and a heat exchanger positioned directly below the boiler and all of the above elements except the gas/solids separator are enclosed within a waterwall structure having outside waterwalls and a central waterwall common to the reactor vessel on one hand and the convection pass boiler and heat exchanger on the other hand. The close proximity of the components of the system eliminate numerous problems present in conventional multi-solid fluidized bed steam generators.

Abstract: A conduit extends through the bottom of an upright type combustion chamber and terminates in a nozzle. A heating medium is contained in the combustion chamber and forms a naturally formed substantially conical shape having an apex. An intake port is provided at the bottom of the combustion chamber at a position corresponding to the apex of the conical shape and extends to the conduit. Particles of the heating medium which are ejected from the nozzle, via the conduit and the intake port, roll along the conical surface of the heating medium and fall into the intake port.

Abstract: Process to ascertain combustion and/or decomposition of gaseous and/or by air or other gas carried particulate pollutants. The invention makes possible an effective and safe combustion and/or decomposition of pollutants not desired to escape into the environment. The pollutants are fed into a combustor (1) in which the pollutants are self combusted and/or are made to self decompose, whereby in the combustor outgoing gas is made to heat ingoing gas and/or by air or other gas carried particulate pollutants through counter current regenerative heat exchange. The invention also refers to an equipment for accomplishment of the process.

Abstract: The present invention relates to an improved method and system for properly and uniformly distributing fluids in upright vessels commonly called vertical shaft kilns or retorts. The distributors disclosed have a unique shape to facilitate movement of particulate matter passing by them and in addition have orifices which are recessed to keep each orifice free of solids with varying sized orifices as needed to provide the flow distribution uniformly across the lateral extent of the retort. Further the distributors are supported at each end by and protrude through nozzles built into the vessel shell to supply connection for external piping. The supports are so formed as to provide for thermal expansion through fluid-tight closures during high temperature operation.

Abstract: Heat exchanger tubes which are immersed in a fluidized bed of a combustion fluidized bed installation are provided with flow deflectors which reduce erosion of the fluidized materials in the bed on the tubes. The flow deflectors are preferably fins or pins, which protrude from the surface of the tubes and which disturb the erosive flow against the outer walls of the tubes. The flow deflectors also increase the surface areas of the tubes and thereby improve heat transfer from the combustion in the fluidized bed to a fluid heat exchanging medium within the tubes.

Abstract: A process for thermal treatment of solid particles in a fluidized bed wherein the solid particles by thermal treatment form a lighter weight fraction and a heavier weight fraction, relative to the total contents of the bed. The process is characterized by use of a selective heavier particle discharge conduit in the sloping bed support and maintenance of a discrete fluid fueled flame in close proximity to and above the opening to the heavier particle discharge conduit. This forms a higher temperature zone in and surrounding the flame, at least about 100.degree. F. higher than the remainder bed temperature. Circulation of solid particles through the flame and its surrounding higher temperature region is promoted both by directing of fluidization gas jets in the fluidized bed support and by the jetting action of the upwardly flowing heavier particle discharge gas.

Abstract: A fluidized combustion device that can be positioned inside the soda boiler of a cellulose factory and rapidly taken out of the boiler when it is desired to use the boiler as a normal soda boiler and as necessary again installed in the boiler.

Abstract: The regenerative heating apparatus (FIG. 1) comprises a pair of regenerators 51a and 51b arranged so that in use while one is being heated by waste gas, the other is preheating air for the combustion of fuel. A reversing valve 58 is connected to each lower end 91a and 91b of the regenerators 51a and 51b, the valve 58 connecting the regenerators 51a and 51b to an inlet 99 for receiving air and an outlet 100 for discharge of the waste gas. The reversing valve 58 is reversible to connect one regenerator to the inlet and the other regenerator to the outlet. Each regenerator incorporates at its upper end a burner (B1 and B2) with as shown in FIG. 2 a body having a passage 2 formed with openings 3 and 4. The opening 4 serves to receive air for combustion when its regenerator is preheating air or to discharge waste gas to the regenerator while the opening 3 serves to supply combusted fuel and air to the furnace 90 or to receive waste gas from the furnace 90.

Abstract: A high temperature surface combustion burner, comprises a burner head having an air fuel mixed gas supply inlet, a burner plate secured to said burner head, wherein the burner plate is made of a ceramic porous body having more than 30% by volume of pores of 25 to 500 .mu.m in mean pore diameter; and a plurality of throughholes having a 0.05 to 5.0 mm diameter and provided in said burner plate at intervals of 2 to 30 mm and substantially vertically extending with respect to the combustion surface.Another surface combustion burner comprises a burner head having an air fuel mixed gas supply inlet, a burner element secured to said burner head, said burner element consisting of a ceramic porous body having pores sufficiently communicated from its inside to its outside for diffusing an air fuel mixed gas, wherein said ceramic porous body has 75 to 95% by volume in total of communicated pores of 0.5 to 5.0 mm in mean pore diameter; and a plurality of throughholes each having a hydraulic diameter of 0.05-5.

Abstract: The invention relates to a method and apparatus for combusting a dirty and/or difficult to burn fuel in a fluidized bed combustor. The fluidized bed and freeboard zone of the combustor are cooled by a non-intrusive counterflow cooling system which controls combustion temperatures and produces a clean, hot gas. The combustor is operated with many combinations of features including: low, in bed fuel injection; use of finely divided fuel; slug flow fluidization; and injection of lime or limestone to effect desulferization or raise the ash melting temperature, if desired.

Abstract: A device for varying the height of a bed in a fluidized combustion chamber inside a pressurized housing. Bed material is supplied to the chamber from hoppers or returned back to the hoppers from the chamber through a supply line. The supply line connects the chamber and the hoppers. The hoppers have means of increasing or decreasing the pressure. To improve the means of both increasing and decreasing pressure in the known device and of cleaning the gas that enters into contact with the material in the hopper, each hopper contains a hot-gas filter that gas can flow through in two directions and each hopper communicates above the filter with a gas connection that can be maintained at either a higher or a lower pressure than the fluidized combustion chamber.

Abstract: Apparatus is described for a non-plugging gas distribution system supplying fluidizing gas to a fluid bed undergoing cooling.

Abstract: A burner construction which comprises a woven metal fabric supported on and surrounding a cylindrical metal support member which has openings along its length and around its periphery. A gas supply tube extends from an entrance end axially into the support member and forms an annular space therebetween. The gas supply tube is provided with openings in its periphery at the entrance end and is impervious at its periphery at the opposite. Gas enters the burner through the supply tube and into the annular space through the openings in the gas supply tube. Gas thereafter flows through the support member openings and through the woven metal fabric and is combusted at the outer surface of the metal fabric.

Abstract: A plant for combustion of a particulate fuel in a fluidized bed in a combustion chamber has the fuel supplied into the bottom of the combustion chamber by means of a pneumatic transportation system via nozzles. Fuel for the plurality of nozzles is transported through a duct to a distributor and from there via individual conduits to the nozzles of the combustion chamber. These conduits include flow-inhibiting, pressure-drop generating means, by means of which a pressure drop is generated between the distributor and the combustion chamber. These pressure-drop inducing means influence the velocity of flow and hence the transport capacity of the transport gas so that a desired, normally uniform, distribution of fuel to the bed is secured.

Abstract: A vertical conduit closed at one end by a head wall and connected at its opposite end to a fluidization gas delivery means is provided with side blowing nozzles longitudinally spaced in planes. A shutter is movable inside the conduit so that the bed in which the conduit is disposed in use can be progressively brought into a state of fluidization by supplying fluidization gas to the nozzles successively and cumulatively starting from the top. The invention obviates the need for the introduction via the bottom of the fluidized bed of compressed air at a high pressure when starting up the fluidization of the bed.

Abstract: Industrial furnace for the combustion of solid, liquid, pasty or gaseous fuels, including at least two fluidized beds through which hot gas passes from the bottom, and which are offset in height in the transport direction of the fuel into the combustion chamber according to a reciprocal delimitation one behind the other and in step, after adjusting a mean combustion temperature between preferably 500.degree. and 800.degree. C. It is further possible to recover from household refuse, and/or industrial refuse similar to household refuse, a fraction of fuel rich in energy and low in noxious products by preparation via drum screens, hammer mills, and sliding plate and rod screens of a particulate size between 120 and 500 mm.

Abstract: An infrared heat device utilizing a ceramic burner tile operating in a confined combustion chamber. Inlet gas flow, metered by an orifice, is boosted as required by the air pressure provided in at least approximately Stoichiometric ratio to compensate for increased back pressure.

Abstract: Apparatus is described for a non-plugging gas distribution system supplying fluidizing gas to a fluid bed undergoing cooling.

Abstract: A fluidized bed reactor (10) wherein a sulfur-containing particulate fuel is combusted or gasified in a fluidized bed (30) of particulate material, which includes a sulfur oxide absorbent, is provided with a solids cooling apparatus (40) adapted to receive particulate material draining from the bed and cool same via indirect heat transfer to a cooling fluid.

Abstract: Apparatus for supplying gas to a fluidization grid which has two separate supply circuits, one for compressed air and one for fluidizing air, the orifices of each circuit ending at the pyramids of the grid. The orifices of each circuit, are arranged in groups, and are connected by pipes to a stator cylinder in which a rotatable rotor tube extends. A motor is arranged to rotate the rotor tube to a number of predetermined positions. The rotor tube is connected to a supply pipework and is pierced with passage openings which are arranged upon rotation of the rotor tube to correspond to the pipes.

Abstract: A burner for use in a heat regeneration system for a combustion furnace. The burner includes a burner shell having two internal chambers, wherein the first chamber is disposed on the flame axis of the burner, and the second chamber surrounds the radial perimeter of the first chamber. A gas permeable, annular regenerative bed separates the first and second chambers such that gas flow between the first and second chambers must travel through the regenerative bed in a direction which is generally radial with respect to the flame axis. The burner has "flue" and "fire" modes of operation. Valving elements are included for supplying combustion air to the second chamber under pressure when the burner is in the fire mode, and for exhausting products of combustion (POC) from the second chamber when the burner is in the flue mode. In the disclosed embodiment, the burner valving elements are annular and integral with the burner body.

Abstract: The combustion gas passages leading to a fluidized bed in a hot water or steam boiler are kept free of deposits which might block them by pulses of gas. The gas pulses may be generated from a pressurized reservoir with periodic or aperiodic openings of a valve in a gas line leading from the reservoir to the passages. Where the bottom of a fluidized bed comprises a pair of plates defining a plenum space therebetween and the combustion gas passages define nozzles extending through the plenum space, combustion air may be fed to the nozzles via the plenum space and the cleaning pulses may also be generated from gas supplied to the plenum space.

Abstract: A nozzle cap for a gas inlet fluidizing nozzle in the bottom plate of a post-combustion bed in a hot water or steam boiler with at least two fluidized beds is provided. Flue gases from an underlying combustion bed enter the post-combustion bed via a plurality of such gas inlet nozzles. Each nozzle cap is formed as a deflecting member for guiding the flue gases to the bed material and is shaped to minimize the risk of clogging of the cap with particles entrained in the flue gases and the risk of the cap being eroded by the fastly moving particles.

Abstract: The invention relates to a method of igniting, upon start-up, a combustion chamber (8) in a power plant with combustion of fuel in a fluidized bed (14). The air flow through the nozzles (13) of the combustion chamber bottom (12) for fluidization of the bed (14) and for combustion of the fuel can be reduced upon start-up; bed material, which is heated to the ignition temperature of a start-up fuel, is transferred from a storage container (40) to the combustion chamber (8), and fuel is supplied to the bed (14). In those cases where the air flow has been reduced during the transfer of the bed material, it is increased again when the fuel is supplied. The invention also relates to a power plant having means for temporarily bypassing the nozzles (13) of the combustion chamber bottom (12) while transferring hot bed material from a storage container (40) to the combustion chamber (8), and a fuel system (30-38) for the supply of fuel to the combustion chamber (8).

Abstract: The burner means for a blast furnace stove having a vertical shell, a combustion chamber adjacent the inside wall of the shell and checkers in the shell includes a generally horizontal first tube extending from the outside of the shell into communication with the combustion chamber, a ceramic tube within the first tube spaced therefrom, and a ceramic nozzle at the inner end of the ceramic tube extending upwardly at an angle between 45.degree. and 90.degree.. Air of fuel gas passes within the first tube around the ceramic tube and the other of the air or fuel passes within the ceramic tube with the gas and air mixing and burning upwardly in the combustion chamber.

Abstract: The enclosure of a generator comprises a combustion zone 1 surrounded at least partially by a heat exchange zone 2, the combustion zone comprising a premix chamber 25 having means for supplying with air at 12 and with fuel 10,11 and inert recycling particles coming from zone 2.The premix chamber has mounted thereover a vertical duct 21 filled with a refractory stack 6 and comprises above the stack an opening 22 serving as overflow communicating with a vertical duct 4 situated outside duct 21 and opening into zone 2. The heat exchange zone 2 is formed as a dense fluidized bed zone and contains fluid circulation tubes 3. The vertical duct 21 serving as combustion hearth is filled with a fixed structure formed by a stack of several layers of spaced parallel bars, offset angularly from one layer to the next.

Abstract: A ring-gap nozzle for distributing a fluid medium over a plate, for instance over a bottom plate in a fluidized bed dryer, having two dish-shaped pressed parts suiting to each other complementarily being assembled in facing relationship and nested into each other and forming a ring gap through which the medium, deflected by 90.degree. or more, flows to the bottom plate, preventing both the settling of the product to be treated in the fluidized bed dryer on the plate as well as the reflux of the product backwardly into the nozzle when the flow of medium is cut off. This type of nozzle is simple to manufacture and does close the passage without any complicated manipulation automatically.