Abstract: Particulate material is heated by directing a flame downwardly along the central axis of a vertically disposed furnace. The particulate material is introduced at a number of locations distributed radially around the flame at the upper end of the furnace. The particulate material is directed downwardly and toward the central axis of the furnace placing the particulate material within the flame as it passes downwardly through the furnace.

Abstract: A fluid bed reactor system for olefin polymerization composed of a cylindrical reaction vessel equipped with a distribution plate and an agitator, characterized in that the distribution plate satisfies the following conditions,(i) each of many passage holes provided in the distribution plate for passage of the fluidizing gas medium is covered with a cap having an opening,(ii) the opening in said cap is provided only on one side of the cap, and the direction (A) of the opening is not opposite to the direction (B) of the rotational flow,(iii) the direction (A) of the opening varies with the distance (d) from the center (X) of the plate to the center (Y) of the hole,(iv) the opening direction (A) of a cap or caps at a hole or holes whose distance (d) is minimum is directed nearer to the center (X) than is the tangential direction of a circle having the center (X) as a center and the distance (d.sub.min.

Abstract: A device for thermal shock testing and thermal cycling of workpieces is provided which comprises at least one fluidized bed chamber for thermally treating a workpiece. Agitation of the area about the workpiece is accomplished by movement of the workpiece, by baffles, or by providing a supplementary gas distributor. The agitation provided increases the flow rate of particles of the fluidized bed particulate media in a localized area about the workpiece, thus increasing the rate of heat transfer between the bed media and the workpiece, and increasing thermal shock capacity of the thermal shock tester.

Abstract: In a reactor for gasification of solid carbonaceous materials in a fluidized bed under elevated pressure and at high temperatures using a hot gasification agent, a feed device for the gasification agent is installed in the lower part of the reactor chamber and traverses this chamber in the form of a bridge, which has an arch joined to the walls of the reactor chamber, said arch consisting of refractory brick and supporting a section of metal pipe. The latter is shielded from the outside by the arch and by a top-mounted structure of refractory material. On the inside, the metal pipe is also provided with a tubular lining of refractory material. Metal pipe, lining, and arch have openings for passage of the gasification agent. The size and shape of the openings are selected to assure passage of the gasification agent even if the parts undergo changes in length as a result of the effects of temperature.

Abstract: An apparatus for rapid burning of thermally pretreated, at least partially calcined fine grained product to produce cememt clinker which includes a thermal reactor having a firing chamber and means for introducing the product to be treated in concurrent flow with and in the area of a flame in the firing chamber. The means for introducing the product includes a vertical shaft which discharges into the firing chamber, together with a deflector which is disposed in the area of the discharge orifice of the shaft, the deflector serving to deflect the hot product which strikes the deflector with substantial kinetic energy due to the force of gravity. The product is broken up into small particles by impacting with the deflector, and is directed substantially parallel to the flame in the firing chamber. The deflector extends at an obtuse angle relative to the axis of the shaft. The apparatus can be connected to a fuel supply and can be utilized as a burner.

Abstract: The apparatus comprises a process vessel, containing a process bed of fluidized particles, having a first submerged port at a first end and a second submerged port at a second end. Both ports are inclined in the same sense so that particles leave the second end of the bed at a higher level than they enter the first end. Fluidized bed material entering the second port becomes defluidized and slides down the port, optionally with the assistance of a fluid injected into the port. The first port conducts particles into the process bed from a second fluidized bed and the second port conducts particles out of the process bed (e.g. into the second bed). The process bed rests on a fluid distributor having a horizontal first part adjoining, and no higher than the level of, the lower end of the first port and a horizontal second part adjoining, and at the level of, the second port, there being a vertical step connecting the first and second distributor parts at a location between the first and second ports.

Abstract: Apparatus for heat treating fine-grained material comprises a rotary kiln into which material is delivered from a multistage preheater that communicates with the kiln via a vertical exhaust gas duct. Treated material is discharged from the kiln to a cooler from which two cooling air ducts extend and communicate with the exhaust gas duct at two vertically spaced zones. Material from the second lowest preheater stage is introduced into the exhaust gas duct adjacent the lower cooling air duct. Fuel is introduced into the exhaust gas duct adjacent each of the cooling air ducts. The apparatus is distinguished by a particularly high degree of deacidification of the raw material and good combustion of the fuel.

Abstract: Perlite and vermiculite are blown by injecting the particles, entrained in a carrier gas, through a burner at the bottom of a fluidized bed furnace, into the latter with, within and codirectionally with the flame to ensure uniformity of the product.

Abstract: A cyclone heat exchanger particularly adapted for direct heat exchange between a granular product and hot exhaust gases from a kiln used in the production of cement, the heat exchanger comprising a housing, a gas feed pipe introducing hot gases tangentially of the housing, a cover extending across the top of the housing, a discharge at the base of the housing for discharging product therefrom. The improvement consists of an immersion pipe extending through the cover and into the housing, the immersion pipe consisting of a plurality of segments extending in the longitudinal direction of the immersion pipe. Holding devices are provided for releasably holding segments in the cover.

Abstract: A fluid bed dryer comprises a pre-dryer of the back mixed type and a post-dryer of the plug flow-type. In the pre-dryer the main part of heat is transferred to the product being dried by means of heating panels arranged above the bed plate. A control bed is interposed between the pre-dryer and the post-dryer and includes one or more temperature sensors for sensing the temperature of the product in the control bed. Heat supply to the heating panels is controlled in response to the temperature sensed by the sensor or sensors in order to maintain the product temperature in the pre-dryer at the dew point and so as to ensure that the drying process proceeds within the region of constant drying rate, and that the product contains little or substantially no unbound moisture despite possible changes in product fed to the pre-dryer.

Abstract: A steam granulation technique involves the injection of a jet of steam into a bed of fludized particles to be granulated. The jet of steam is substantially enveloped by a jet of air to inhibit the premature condensation of the steam onto the fluidized particles and/or the condensation of the steam onto neighboring walls of an apparatus employed to fluidize the particles, thereby inhibiting excessive wetting and lumping of the particles during their granulation.

Abstract: An adaptive control system for a bulk material dryer measures the thermal demand of bulk material to be dried in a dryer and adjusts the thermal output of the dryer to match the measured demand. The system contemplates that the dryer will require a response period to fully meet a change in demand and coordinates the introduction of material into the dryer with that response time. The system is automatically responsive to changes in both the moisture level and mass flow rate of the bulk material to be dried, adjusting the thermal output of the dryer to changes in each of these variables. The system preferably includes a feedback sensor used to make final adjustments in the dryer output.

Abstract: A method and apparatus for calcining lime, dolomite or similar materials in which the raw material to be calcined is preheated in a preheating zone by exhaust gases from a calcining zone, cooled by means of combustion air in a cooling zone, the combustion air passing from said cooling zone into said calcining zone and then into the preheating zone. A specific improvement of the invention resides in adding fuel in the calcining zone at a plurality of spaced locations along the calcining zone in the direction of flow of the combustion air therethrough.

Abstract: The dryer includes at least one vessel, means for heating the outside of the vessel to dry wet material in the vessel and a gas inlet in the lower section of the vessel.The pressure of the gas fed to the gas inlet is predetermined and transports the material through the vessel in the form of a loose material bed. The dried material is removed from the vessel.A high pressure gas pulse generator feeds pulses into the vessel to agitate the material in the loose bed to prevent compaction of the material, and avoid channeling through the loose material bed. The motion of the loose material destroys vapor film on the inside shell of the vessel to maintain good heat transfer through the shell.

Abstract: For processing matter in a turbulent mass of particulate material, a substantially annular processing region (14; 104; 206) is provided and is preferably in the form of a substantially annular processing chamber having a radially inner wall which includes a waist (38; 122). A flow of fluid and matter to be processed are admitted to the processing region through one or more inlets (28, 46; 108, 124; 214, 220) with the flow of fluid being directed generally circumferentially into the processing region. In the processing region, matter to be processed is embedded in a compact turbulent band of particulate material for processing. Once processing is complete, the processed matter is withdrawn from the processing region, preferably by entrainment in an exhaust flow of the fluid.

Abstract: The invention relates to plant (1) and to a method for regenerating sand from foundry cores and moulds by calcination in a fluidized-bed furnace (2), the main characteristic of which lies in the fact that the fumes leaving the calcining furnace are used to heat a current of air which is then used, in its turn, to heat the sand to be treated at its inlet to the calcining furnace, and in that the current of air cooled by the sand to be treated is then heated by means of the purified sand leaving the calcining furnace and is then used as combustion air in the calcining furnace.

Abstract: A process for the calcination of a solid pulverulent material comprises the steps of gasifying a solid fuel in a fluidized bed to produce an ascending current of gaseous fuel, and injecting the material in an oxidizing carrier gas into the ascending gaseous fuel current above the fluidized bed of solid fuel to disperse the pulverulent material in the gaseous fuel current, the flow velocity of the gases in the zone of injection of the material into the current being sufficient to entrain the material in the gases and to prevent them from falling into the fluidized bed. An apparatus for the calcination comprises a calcination chamber whose bottom is a grid carrying a bed of solid fuel through which air is blown to produce the ascending current of gaseous fuel in the chamber. An array of nozzles in an upper portion of the chamber is used to inject the pulverulent material suspended in the carrier gas into the chamber above the fluidized bed.

Abstract: A bed support, and a fluidizing bed reactor incorporating the bed support, the bed support including a horizontal support surface with a centrally disposed conduit for removing tramp material and/or agglomerated material from the reactor. The horizontal support surface has fluidizing air source jet nozzles for directing pressurized air toward the area above the conduit. In a first embodiment, the conduit has downwardly diverging walls. In a second embodiment, the horizontal support surface further includes a bar grate having central fluidizing air source jet nozzles positioned within the conduit. The method of operating the fluidized bed reactor includes directing pressurized air at an angle to the horizontal support surface both for fluidizing the bed and for moving the tramp material and/or agglomerated material toward the conduit for removal from the reactor through the conduit.

Abstract: The present invention is directed to a fluidized-bed combustion apparatus provided with a U-shaped combustion zone. A cyclone is disposed in the combustion zone for recycling solid particulate material. The combustion zone configuration and the recycling feature provide relatively long residence times and low freeboard heights to maximize combustion of combustible material, reduce nitrogen oxides, and enhance sulfur oxide reduction.

Abstract: A high temperature (1000.degree. C. or higher) gas distributor for a fluidized bed, comprising a plurality of plates which are made of an oxide-based burned refractory material and which are reduced in thickness in the longitudinal direction thereof leaving both sides thicker, refractory supporting bricks holding in position both sides of the plates, and refractory holding bricks holding in position the above refractory supporting bricks and the ends of the plates.

Abstract: A method and mechanism for heat treating a pulverulent comminuted raw material in the process of making cement including preheating the material, passing the material through a first reaction zone, supplying a first fuel supply to the first zone for supplying thermal energy for carrying out the calcination reaction, separating the material from the hot gases received from the first reaction zone and delivering the material to a second reaction zone to which is supplied a second fuel supply for supplying thermal energy for the calcination reaction in the second zone and separating the material from the hot gases from the second zone and delivering the material to a sintering kiln and then passing it to a cooler with the air from the cooler supplied to support combustion in the first zone, and with the arrangement preferably arranged in two parallel flows with each flow path containing the preheater, and the reaction zones and separators with the material flows combining just as they enter the sintering zone.

Abstract: The invention relates to apparatus for introducing fine material into a combustion zone by means of an air duct which has a constriction in the region of its junction with the material duct in such a way that the rate of flow is considerably increased at the point where the material is introduced and this favors the loosening of the material stream and the delivery of the material to the combustion zone.

Abstract: An air bearing and heating system for use in moving and heating integrated circuit chip carriers (12) prior to their being tested by an electronic tester (10) is the subject of this patent application. The system includes a magazine (18) having a plurality of tracks (24) spaced vertically therein. Each track (24) includes an air-permeable wall (62, 62') through which air in a plenum (52) beneath the wall (62, 62') seeps. The air forms a cushion on the surfaces (64) of the sloped tracks (24) in order to float chip carriers (12), positioned for movement down the tracks (24) therealong.The air can be heated by a heater (104) prior to the time it is introduced to form the air cushion so that the chip carriers (12) will be heated as they are floated down the tracks (24).Similarly, the system can be provided with a distribution member (28) by which carriers (12) are conveyed away from the test site (14) of the handler.

Abstract: The invention relates to a multiple-stage heat exchanger 1 in which at least one of the lower heat exchange stages contains a deflector/separator with a horizontal gas inlet pipe and a gas outlet, and at least the upper heat exchange stage has a conventional cyclone. This results in a considerable reduction in the energy requirement, the size and height of the construction.

Abstract: This invention is directed to a method and an apparatus to heat certain particles. These certain particles are heated to make them more desirable. In the heating of these particles, it is often desirable to expand the particles to make a light-weight aggregate. The light-weight aggregate may be used in making a building material or the like. In carrying out the process of heating these particles, there is used air for combustion of the combustible fuel and only a minimum of air for carrying of the particles or expansion of the particles.

Abstract: A method for heat treating a material such as gypsum mineral, consists in burning a fuel in a combustion bed which is in heat exchange contact through bounding walls with beds of the material to be heated. Combustion gases are passed from the combustor through the heat treatment vessels containing beds and these gases then serve to fluidize at least partly and add heat to the beds through the agency of distributors.

Abstract: A fluidized bed heat exchanger in which a perforated plate is disposed within a housing for supporting a bed of particulate material which is introduced into the housing through an inlet. Air is passed through the plate to fluidize the particulate material and a drain pipe is provided for discharging the spent material from the bed. The flow rate of air introduced into the bed is increased in a direction across said bed from said inlet to said drain pipe to promote the circulation of the bed materials from the inlet to the drain pipe.

Abstract: The present invention is directed to a combined fluidized bed retorting and combustion system particularly useful for extracting energy values from oil shale. The oil-shale retort and combustor are disposed side-by-side and in registry with one another through passageways in a partition therebetween. The passageways in the partition are submerged below the top of the respective fluid beds to preclude admixing or the product gases from the two chambers. The solid oil shale or bed material is transported through the chambers by inclining or slanting the fluidizing medium distributor so that the solid bed material, when fluidized, moves in the direction of the downward slope of the distributor.

Abstract: A fluidized bed heat exchanger having a perforated support plate supporting relatively lightweight absorbent material particles and relatively heavy fuel ash particles includes a drain through which a flow of air defining a separating air screen retains the adsorbent material particles in the bed but allows the fuel ash particles to fall into the drain.

Abstract: Apparatus for heat treating a particulate commodity comprising an enclosure having a lower wall in the form of a concave, perforate deck, supply means for supplying pressurized fluid at a controlled temperature through the deck to fluidize and heat treat a bed of particles in the enclosure and transfer means for controlledly moving the particles continuously or stepwise along the deck. A method of heat treating the particulate commodity comprising supporting said commodity in a fluidized bed above a concave, perforate deck, supplying pressurized fluid at a controlled temperature through the deck to fluidize and heat treat the commodity, controlling the residence time of the commodity in the enclosure by controlledly moving the commodity along the deck using transfer means, and enhancing fluidization of the bed by reducing segregation within the bed using said transfer means. The commodity e.g. a food product such as peanuts is heat-treated uniformly under precisely controlled conditions.

Abstract: A method and apparatus for treating granular materials which require to be heated to drive off volatile constituents and which require to be cooled, for example foundry sand containing an organic binder. The method comprises the step of maintaining a mass of the material at a treatment temperature lying in the range 240.degree. C.-400.degree. C. for between four and thirty hours. The mass may be initially heated by virtue of a manufacturing process in which the mass has been previously used. Alternatively, the mass may be initially heated by a preheating step such as heating in a fluidized bed. Alternatively, the mass may be heated by being placed in heat transfer relationship with a second mass of the material which has been previously heated, for example, in a fluidized bed. Apparatus for performing the method is also disclosed.

Abstract: A wall arrangement for a shell type chamber in which the wall is provided with gaps between them enabling expansion when the temperature of the chamber is increasing. The particular arrangement further provides means for preventing inert material packing said gaps which would prevent expansion of the walls. The means for preventing the insert material packing the gaps comprises gas injector means arranged to force gas into the gap.

Abstract: A fluidized bed shell boiler for producing steam or hot water or a fluidized bed hot gas generator or incinerator in which the position at which bed material is deposited downstream of the bed is controlled. A baffle of firebrick with gas-flow passages extending through the baffle is positioned in the tube downstream of the bed.Gas velocities are distributed across the tube so that bed material is preferentially deposited in the combustion chamber downstream of the furnace tube.Deposition in the furnace tube is reduced to zero or to a negligible amount and deposition downstream of the combustion chamber is reduced.

Abstract: Method and apparatus are disclosed for producing a useful stream of hot gas from a fluidized bed combustor and controlling bed temperature by introducing cooling gas into the freeboard region of the combustor. The cooling gas is introduced by a plurality of inlet ports located within the combustion chamber or about its periphery. The cooling gas contacts particulate matter in the freeboard region, extracting heat therefrom. Cooled particulate matter either falls back into the bed or is returned to the bed from a separator downstream of the combustion chamber.

Abstract: In a method for continuously burning particles in a gas or oil heated vertical furnace in which the particles are charged from an uppermost part of the space, and the particles bed fluidized by a burning gas flow is formed in a vertically successive downward arrangement and then the burned particles are discharged out of the bottom of the furnace after cooling, the improvement comprises the steps of: providing the furnace with a plurality of downwardly vertically successive zone, including a precipitation zone of the particles at an uppermost part in the furnace, a lower upward flow velocity zone having low upward stream of the burning gas (referred to as "rich fluidized bed", hereinafter) and a higher upward flow velocity zone having high upward stream of the burning gas (referred to as "lean fluidized bed", hereinafter) underneath the precipitation zone wherein the lean fluidized bed is formed beneath and adjacent to the rich fluidized zone, and feeding the particles, burning them successively through the z

Abstract: In a calcining furnace usable particularly for regenerating sands used in casting boxes and cores, a bed of refractory particles is fluidized by means of a combustible gas which is fed into the bed together with air, so as to enable the combustible gas to burn. The base wall on which the bed of refractory particles is supported has a plurality of holes for the air supply. Each hole for the air supply has associated therewith a nozzle for supplying the combustible gas, disposed coaxially with the respective hole and having at least one discharge aperture for the combustible gas disposed adjacent the plane of the base plate.

Abstract: A method of treating a particulate material in a fluidized bed reactor includes supplying a particulate material into a working space above at least one zone which is characterized by reduced passage of a fluidizing gas. A fluidizing bed reactor is designed so that its means for supplying a particulate material is arranged above at least one zone of the reduced passage of the fluidizing gas. The passage of the fluidizing gas in this zone can be completely prevented. Jalousie-shaped inserts are arranged above edges of the zone and have inclined surfaces.

Abstract: The invention relates to a method for burning fine-grain material, particularly for the manufacture of cement clinker from cement raw meal. The material is thermally treated in a multi-stage burning process with a pre-heating stage, a calcining stage with a high-degree of calcination, a sintering stage in a very short rotary kiln and a cooling stage. Fuel is introduced both into the sintering stage in the short rotary kiln as well as into the calcinating stage. Hot exhaust air from the cooling stage is supplied both to the sintering stage as well as to the calcining stage as furnace air. The invention also relates to an apparatus for the manufacture of mineral products of the burning process such as cement clinker.

Abstract: A heat exchanger for exchanging heat between solid particles and a gas where the particles fall vertically through a column under gravitational forces and the gas flows upwardly in the column. The heat exchanger has at least one stage in the column including a stack of packing elements supported by a support having openings through which gas may flow at a velocity sufficient to form a loose fluidized bed of particles. A grill is positioned in the lower part of the column through which gas may flow to support a dense fluidized bed of particles.

Abstract: A fluidized bed heat exchanger in which an air distributor plate assembly is disposed within an enclosure for supporting a bed of particulate material. The plate assembly includes a plurality of horizontal, spaced tubes through which water is passed to cool the assembly. Air is passed from an air plenum through openings formed in the plate assembly to fluidize the particulate material. Insulation is disposed on the lower surface of the plate assembly to insulate the latter from the heat of the fluidizing air, and the upper surface of the plate assembly is insulated from the high temperatures occurring in the bed.

Abstract: A gas distributor for fluidizing a bed of particulate matter which provides for minimum dissipation of particle energy from a particulate-laden gas stream on a distributor surface is disclosed. The gas distributor allows the particulate-laden gas stream to contact the surfaces of the distributor at about 90.degree. or 0.degree. which are angles of impact for low erosion. Opposing particulate-laden gas streams are made to contact each other which removes particle kinetic energy while minimizing erosion before fluidizing the bed of particulate matter.A method to minimize erosion of a gas distributor for fluidizing a bed of particulate matter from a particulate-laden gas stream is also disclosed.

Abstract: Disclosed is an apparatus for calcining raw materials in the form of powder or particles. The gases entrain the particles to spiral upward in the calcining furnace. In an upper throttle chamber the relatively coarse particles which have not been completely calcined are separated from the gas flow and returned into the calcining zone to be calcined again. This pattern of material flow is repeated several times. The calcining efficiency can be improved, so that the furnace can be made small in size. The uniformly calcined particles are discharged from the top of the furnace and introduced into one or more cyclone separators through an outlet duct including a 180.degree. bend section.

Abstract: In a process of producing cement, a powdered mixture of raw materials is de-acidified in a calcinator and subsequently burned in a kiln. Before de-acidification, the mixture is preheated in a plurality of heat exchange stages by the exhaust gases from the kiln and from the calcinator, which are passed through respective parallel series of the heat exchange stages, the powdered mixture being passed from heat exchange units of each series to associated heat exchange units of the other series. The heat efficiency of this process is improved by combining the exhaust gas streams from the kiln and from the calcinator coming from the parallel series of heat exchange stages, and then feeding the combined stream of exhaust gases to another heat exchange stage, which is the last stage in the flow path of the exhaust gases and to which the cold powdered mixture of raw materials is fed.

Abstract: A fluidized bed heat exchanger in which a perforated plate is disposed within a housing for supporting a bed of particulate material. Air is passed through the plate to fluidize the particulate material and a mixture of air and additional particulate material is introduced to said bed and deflected into said bed in a manner to induce diffusion and circulation of the bed materials in the bed.

Abstract: A drain and sampling valve assembly for a fluidized bed reactor in which a pipe extends from the fluidized bed supporting structure to a location externally of said reactor. A valve seat is supported by said supporting structure and a valve stem is disposed in the pipe and extends for the length of the pipe and has a valve head mounted at one end of the stem for cooperating with the valve seat. A mechanical actuator assembly is provided externally of said reactor for selectively moving the stem relative to the pipe and the movement of the valve head relative to the valve seat to control the flow of material from the fluidized bed into the pipe. A discharge pipe and a sampling valve cooperate with the other end of the first mentioned pipe for selectively controlling the discharge of material from said latter pipe for permitting samples to be taken.

Abstract: A bottom for a fluidized bed conveyor is composed of a plurality of members provided with openings and located in contact with each other so that their points of contact are gas impermeable at least during operation of a fluidized bed. The openings may be formed as circumferentially closed holes and/or as laterally open recesses. The members may laterally abut against each other, or may be provided with interengaging lateral projections. The members may be located so that at cold temperatures small intermediate spaces remain therebetween, which spaces are closed during operation as a result of thermal expansion of the members under the action of high working temperatures. Bracing element or elements may be provided which urge the members toward one another.

Abstract: A combustor grid for use in an incinerator having air bars for distribution of fluidizing air. Air is distributed from a source of pressurized air to a configuration of air bars in fluid communication with each other. Each air bar in the grid has an upper surface with air injection ports and side walls which converge toward the bottom surface. The air injectors may be refractory covered metal tubes on a conduit or individual air nozzles.

Abstract: A fluidized bed combustor having a distributor plate assembly including an inverted frustopyramidal surface with slots and offset shields thereover to form laterally oriented air flow openings into the combustion chamber from a first plenum for debris particle classification along said surface. At the bottom of each frustopyramidal surface is an outlet for classified debris. Air flow riser tubes project up from a second plenum to a position above said surface. Forced air is supplied to the slots and the risers, with means to regulate relative flow to them.Projecting down from the debris outlets are drop tubes having cooling fins, such tubes connecting to inlets of an auger conveyor. The auger conveyor has a coolant-cooled housing and a coolant-cooled auger.

Abstract: A fluidized bed heat exchanger in which a perforated plate is disposed within a housing for supporting a bed of particulate material which is introduced into the housing through an inlet. Air is passed through the plate to fluidize the particulate material and a drain pipe is provided for discharging the spent material from the bed. A plurality of nozzles are provided in association with the perforations in the plate for directing air toward the drain pipe to promote the circulation of the bed materials from the inlet to the drain pipe.

Abstract: A fluid bed dryer includes a tank with an upright wall, a top, and a floor which rotates under a plurality of blades adjacent the floor and fixed to an inner annular baffle. A gas manifold is defined between the tank wall and the baffle, and opens under the baffle into a drying space in the tank.A pulse jet engine pumps pulsating hot gas and sonic waves to the gas manifold to fluidize a bed of moist particles which are introduced into the drying space above the blades. There is a time average uniform exposure of the bed to the fluidizing gas effected by continuously changing the exposure of the particles to the gas. Pulsating hot gas and sonic energy waves flow from the periphery of the tank toward the center of the dryer. The pulse jet engine also supplies an auxiliary gas inlet at the side of the tank to maintain a swirl of gas above the fluidized bed. An adjustable bypass diverts the flow of gas from the auxiliary inlet to the gas manifold for adjusting the strength of the gas swirl.