Abstract: A hybrid drying apparatus including: a bed portion having a horizontally disposed top surface; an object-to-be-dried supplying portion configured to spread an object to be dried on the top surface of the bed portion; and a driving unit configured to rotate and drive the bed portion or the object-to-be-dried supplying portion, wherein the object to be dried supplied from the object-to-be-dried supplying portion is spread on the top surface of the bed portion while the bed portion or the object-to-be-dried supplying portion is rotated, and the top surface of the bed portion is heated in such a manner that a lower portion of the bed portion is primarily heated so that the bed portion is used to dry the object to be dried coated on the top surface of the bed portion by the object-to-be-dried supplying portion.

Abstract: The present invention provides a system and a process for preparing activated carbon from fly ash. The system of the present invention comprises a flotation system and a carbonization system. The present invention has the following advantages. Firstly, since a fuel gas-flue gas loop structure is arranged, the combustible fuel gas produced in carbonization process enters the combustion means for combustion via this loop structure, and also via this loop structure, the high temperature flue gas generated by the combustion enters the carbonization furnace to heat up and carbonize the charcoal powder raw material within the carbonization furnace. Such a solution not only saves energy, but also prevents a substantial amount of combustible gas from being emitted to the atmosphere, thereby reducing environmental pollution. Secondly, since two cylinders are arranged in the carbonization furnace, the charcoal powder raw material in the inner cylinder enters the outer cylinder and then exits from the outer cylinder.

Abstract: An apparatus and method for recovering heat radiating from the outer surface of a rotary kiln includes an enclosure formed as a stationary housing that has an axially extending opening and closure flaps on circumferential ends of the housing extending towards the shell to form a chamber and an exhaust fan, arranged to draw a flow of air into the housing, which flow of air recovers heat from the kiln shell and is discharged from the chamber for heat recovery therefrom.

Abstract: An indirect heating furnace heats a substance in a reaction tube with a high-temperature combustion gas without contact between the substance and the combustion gas. The reaction tube is a stationary ceramic tube. A combustion device for supplying said heating high-temperature combustion gas into the furnace in comprised of at least one pair of regenerative burners.

Abstract: A process for reclaiming salvaged asphalt includes feeding salvaged asphalt mixed with new sands, stones and tar in a designed proportion into a double-layer drying machine including inner and outer gyroscopic drums; indirectly heating the salvaged asphalt in the drying machine by using a plurality of burners disposed externally to dry the salvaged asphalt, the heat thus generated being recycled via a draft tube into the drying machine to further heat the salvaged asphalt until the tar in the mixture starts to soften at about 80° C.; and mixing the salvaged asphalt with tar to form rejuvenated asphalt product when they travel to the outer gyroscopic drum in which the temperature reaches and the temperature of the stones contained in the salvaged asphalt also reaches a temperature of 160° C. for fusion with the tar.

Abstract: An apparatus and process for fabricating tubing used in the making of chalcogenide fibers. The apparatus features a three-sectioned melt/spin ampoule that allows for fabricating the chalcogenide tubing without introducing impurities and contaminants, in a self-contained apparatus.

Abstract: Apparatus (1) and process for treating particulate material or powder (33) of a size capable of being fluidized in a retort (31) mounted for rotation on a pair of end axles (18, 41). Retort (31) is mounted on a tilt frame (5) for tilting movement in a vertical plane. Gas conduits (18A, 18B) are mounted within an axle (18) for the supply and exhaust of gas for retort (31). A conduit (55) mounted within the other axle (41) permits particulate material to be passed into or out of the retort (31) as shown in FIG. 1B. A removable injection assembly (90, FIG. 10) is utilized for the injection of additional particulate material. A removable sampling assembly (95, FIG. 11) is utilized for removing a sample of the particulate material from the retort (31). As the retort (31) is rotated, particles of the particulate material are constantly intermingled with each other and the walls of the retort (31). Microwave energy as shown in FIGS. 13-14 may be utilized to heat or dry materials within the retort (31).

Abstract: The invention relates to a method and device for treating contaminated materials, specially infected materials, which are fed to endless screws (5, 12) via a feed hopper (2) and are heated, disinfected or sterilized in addition to being discharged through an ejection system (21).

Abstract: A rotary kiln (1) is equipped with a horizontal kiln drum (3), arranged rotatable and drivable in a furnace body (2), which kiln drum is closed at the charging and delivery side by end plates (4, 5) forming central charging or delivery openings (6, 7), respectively, and which can be heated from outside via a heating chamber (15) surrounding the drum shell and admitted with heating medium. To achieve a simple and solid drum construction at a good thermic efficiency, the kiln drum (3) consists of U-sections (18) arranged side by side along the drum circumference between the end plates (4, 5), which point radially inward with their open section side, and which are interconnected longitudinally in the touching end zones (19) of the section limbs (20), and along the circumference via reinforcing elements (23), having an axial distance to each other, bridging the remaining longitudinal gaps (21) between the section webs (22).

Abstract: A rotary tube furnace suitable for operation in controlled atmospheres at temperatures in the range of 1500.degree. to 2800.degree. comprises a generally horizontal rotatable graphite tube slidably supported on water-cooled split ring graphite bearings. The graphite tube is rotated by means of a stainless steel drive plate and is contained within a flexible atmospheric sealing assembly and enclosure for the containment of a selected atmosphere around and within the tube and allows for the co-current or counter-current flow of gas during operation. Radiation baffles in the interior of the graphite tube inhibit radiant heat loss at the ends of the tube. The graphite tube may be constructed in two or more sections having threaded ends for ease of installation as well as removal or replacement for maintenance purposes. A heating section of the tube is heated by a plurality of graphite electrical heating elements contained within an insulated heating chamber.

Abstract: A furnace for manufacturing ceramics is disclosed. The furnace contains a cylindrical heat resistant container, a furnace body for heating the cylindrical heat resistant container, and driving means for driving the cylindrical heat resistant container. The cylindrical heat resistant container rotates about a central shaft. At the same time, a first end and alternately a second end of the cylindrical heat resistant container are raised and lowered periodically, thus creating a seesaw motion while any material contained in the cylindrical heat resistant container is fired by the furnace body.

Abstract: A flighted, horizontally inclined rotary retort, heated externally by flame, hot gases, steam or other sources of heat. The retort shall have sufficient flight area to transport the coal through the retort in the predetermined time. The coal being processed in this retort is prevented from becoming exothermic by provision for a countercurrent flow of blanket gas, heated to a predetermined temperature below exotherm, to prevent coal surface temperatures from rising above the ignition temperature. The retort accommodates oversize pieces of raw coal by having alternating long and short flights, thus allowing greater space between long flights and allowing the larger pieces to be carried over the center pipe by the wiping action of the long flights. The retort will also be provided with an internal pipe, mounted on the center line of the shell.

Abstract: A carbon reactivation apparatus has a fossil fuel kiln adjacent to a rotary dryer and flue gas from the kiln flows through the dryer co-currently with carbon particles to provide a more efficient process than previously known. The apparatus has a rotary kiln with a drum therein sloped downwards from a feed end to a discharge end, a furnace shell surrounding at least a portion of the drum with a fossil fuel heater and hot gases from within the shell heat the rotary kiln. A rotary dryer slopes downwards from an inlet end to an outlet end and carbon particles to be reactivated are fed into the inlet end. Ducting from the shell surrounding the drum of the rotary kiln extends to the inlet end of the rotary dryer for hot gases to flow along the dryer to the outlet end in the same direction as the carbon particles.

Abstract: A direct heat rotary calciner and method for providing improved thermal treatment of particulate material comprises a rotary tube having a plurality of screened apertures along the length thereof. Material to be treated is passed through the rotating tube and contacted during passage with a cross-flow of heated gases entering and leaving through the screened apertures. At least a portion of the internal wall of the tube may be provided with spiral flights to aid in the conveyance of the particulate material through the rotating tube.

Abstract: A device for combustion of moist fuel includes a combustion chamber with a moving fire grate disposed at a bottom portion thereof and a drum dryer located within the combustion chamber above the fire grate. The dryer drum rotates and includes therein an involuted drum in communication with a feeding apparatus external to the combustion chamber. The feeding apparatus transports fuel from a bin to the involuted drum. As the drum dryer rotates the fuel therein moves toward an end thereof and is dried by the heat of the combustion chamber. From an end of the drum dryer, the dried fuel falls onto the fire grate and is burned.

Abstract: A carbon reactivation apparatus has a fossil fuel kiln adjacent to a rotary dryer and flue gas from the kiln flows through the dryer co-currently with carbon particles to provide a more efficient process than previously known. The apparatus has a rotary kiln with a drum therein sloped downwards from a feed end to a discharge end, a furnace shell surrounding at least a portion of the drum with a fossil fuel heater and hot gases from within the shell heat the rotary kiln. A rotary dryer slopes downwards from an inlet end to an outlet end and carbon particles to be reactivated are fed into the inlet end. Ducting from the shell surrounding the drum of the rotary kiln extends to the inlet end of the rotary dryer for hot gases to flow along the dryer to the outlet end in the same direction as the carbon particles.

Abstract: A heating chamber for solid material, preferably a low-temperature carbonization drum for waste, is rotatable about its longitudinal axis and is equipped with a number of heating tubes that are disposed in an interior space and are aligned approximately parallel to one another. In order to ensure that only fine material can collect between the heating tubes and the inner wall surface of the heating chamber, the heating tubes, as viewed in cross-section, are disposed in a virtually closed row along the wall. Dummy tubes which are preferably easy to remove and preferably have the same diameter as the heating tubes, are located in this row, which may be circular.

Abstract: A low-temperature carbonization drum for waste includes many heating tubes located in the interior. The tubes are each secured by one end to a first end plate and by the other end to a second end plate. At least one support location for supporting the heating tubes is provided between the two end plates to prevent them from sagging. Each support location is divided into at least two spaced-apart partial supports, each with one bracket configuration. Each bracket configuration includes a plurality of support brackets that are located in the same plane as one another. The support brackets are located one after another (are staggered) and are rotationally offset from one another. As a result, the solid material in the waste can be transported largely unimpeded past the support locations.

Abstract: A heating chamber is rotatable about its longitudinal axis and contains a number of heating tubes orientated parallel to each other. Solid material which is lifted up during the rotation can become detached from the heating tubes and upon impact can lead to damage to heating tubes which are situated below. In order to prevent such an occurrence, baffle shells are provided on the heating tubes. The baffle shells are formed of a resistant material and offer protection against surface damage. The heating tubes are preferably disposed in radially orientated rows.

Abstract: A combined soil remediation and HMA plant is provided having a rotary dryer, a rotary soil incinerator, and a refractory lined duct connecting the incinerator to the dryer and serving as a conduit via which hot gases, forming the primary and possibly sole heat source used to heat raw aggregate in the dryer, are conveyed from the incinerator to the dryer. The duct also acts as an afterburner in which volatile organic compounds, particles of contaminated dust, and other combustible products not destroyed in the incinerator are destroyed. The plant further includes a mixer 1) receiving both reclaimed soil from the incinerator and heated and dried aggregate from the dryer and 2) mixing both materials with liquid asphalt and possibly RAP and/or dust from the system's baghouse assembly to form HMA.

Abstract: A tunnel type incinerator with cylindrical inner and outer barrels which are rotated in opposite directions relative to each other. A large number of crushing blades or protrusions are disposed and engaged with each other in a spiral shape on the wall of the barrels, a hopper is disposed on a side of a hold member which is joined with the inner and outer barrels and a bucket is disposed on a lower opposite side of the hold member. Charged waste from the hopper is crushed on the crushing blades and moved to the front end portion of the barrel by a screw ribbon and burned up by the indirect heating of a combustion tube with burners, and a non combustioned gas tube is mounted over the hold member, such that the non combustioned gas produced in the inner and outer barrels is recycled to burn up the non combustioned gas.

Abstract: A rotating tube heat treatment installation, for example a rotating tubular kiln for the thermal splitting of MgSO.sub.3, or a slag cooler for the separation of salts and aluminum, comprises as the main replaceable component, a rotating tube (1) which is surrounded by a tubular jacket (2) and separated therefrom by a gap. The tubular jacket (2) is linked to the rotating tube (1) by means of a carrier system, and has drive (8) and possible bearing races and bandings (9) mounted externally. The connections (3, 4) for the heat exchange fluid are disposed at its ends, and thermal insulation, in particular light insulation (7), is fitted internally. In this way the rotating tube, which is exposed to corrosion and thermal stresses, is simplified structurally and can be readily replaced.

Abstract: Both indirect and counterflow direct heating are utilized in a dryer to achieve improved efficiency with a reduced tendency to char or damage the treated material. A horizontal drum has a first segment of aluminum and a second section of stainless steel and is disposed within a heating chamber which is divided into two sections by a baffle. Hot combustion gases are introduced to the chamber and flow to the end of the heating chamber to the rear of the drum and enter the drum. The gases counterflow through the drum in a direction opposite to material moving through the drum to exchange heat. The gases remove moisture from the material and exit the drum into a preheat zone of the chamber where the moisture laden gases condense on the drum's surfaces. The exhaust gases then proceed up two stacks. The interior surfaces of the heating chamber and the preheat chamber are insulated to increase thermal efficiency.

Abstract: Heated surrogate medium is placed in heat transfer relation with high moisture content waste material where water is evaporated to steam. By agitating the mixture of waste material and heated surrogate medium, particulate matter from the waste material is entrained in the steam. A separator separates the steam and dried waste material and supplies the dried waste material to a burner for heating the surrogate medium. The separated steam flows to a stack or to the surrogate medium and oversized waste material discharged through an outlet of the drying zone for flowing additional particulate material from the waste material flowing through the discharge outlet back into the drying zone. The discharged surrogate medium and the oversized waste material are separated and the separated surrogate medium is recycled into the heating zone.

Abstract: A garbage processing vehicle includes a rotational fermentation drum device which is disposed on a loading platform of a vehicle, for mixing garbage with aerobic microorganisms and air in a rotational drum and providing conditions favorable to fermentation. By processing the garbage in a vehicle, device installation space can be saved and the garbage can be processed during transportation. Exhaust heat of the vehicle's engine is conducted to a peripheral space of the drum and air sucked from the periphery of the engine is supplied to the inside of the drum to promote fermentation.

Abstract: A method of retorting organic matter including the steps of advancing the organic matter through a chamber in the absence of oxygen, sensing the temperature in the chamber at a plurality of locations along the length of the chamber, individually adjusting the heat generated by a plurality of burners along the length of the chamber in response to the temperature sensed at the locations, utilizing the generated heat to selectively raise the temperature of the organic matter at a plurality of locations along the length of the chamber so as to convert the organic matter into a plurality of byproducts, and burning at least one of the byproducts in the burners.

Abstract: A method and apparatus for drying solids such as bark, peat, wet coal or the like utilizes waste heat recovered from a rotary kiln. Solids are dried by simultaneously using both the radiation heat of the shell surface of the kiln and the heat of hot flue gases being discharged from the kiln. The solids are dried in a drying space which is defined by the shell surface of the rotary kiln and a jacket surrounding at least part of the shell surface of the kiln. Flue gases from the rotary kiln are passed with solids through the drying space. The kiln may be used for combusting lime.

Abstract: A reaction furnace includes a rotating core within a heated shell, the core and shell defining an active annular zone. An interrupted helical screw carried by the core conveys material from an inlet at one end of the zone to an outlet at the opposite end of the zone. The furnace is operated with the annulus only partially filled. Volatiles rise to a void space at the top of the annulus and are drawn off.

Abstract: A clothes dryer equipped with a condensation unit (23, 38, 73) in which the cooling water that is fed is brought into direct contact with the humid air to dehumidify the humid air. The condensation unit (23, 38, 73) of the clothes dryer comprises a first duct (24, 39, 75) connected at its one end to the delivery portion of the circulating fan (20) and arranged with its other end being directed downwardly of the dryer housing; a second duct (25, 40, 76) connected at its one end to the other end of the first duct (24, 39, 75) and connected at its other end to the heater duct (8d); a cooling water pouring port for feeding cooling water to the second duct; cooling means for bringing the cooling water into direct contact with the humid air; and a water drain port for draining from the second duct (25, 40, 76) the water condensed from the humid air and the cooling water.

Abstract: A new anhydrous sodium dichromate in flakes, Na.sub.2 Cr.sub.2 O.sub.7, m.p. 356.degree. C. (dec. 400.degree. C.) is described, characterized in that it comes in flakes with an area of approx. 1 cm.sup.2, thickness 0.5 mm and apparent specific gravity 1.10 (absolute 2.748) at 25.degree. C; it is not deliquescent, nor does it become powdery. It is prepared from dihydrate sodium dichromate or aqueous solutions thereof using a new process in two stages, namely a) evaporation-melting of the dihydrate salt or concentrated aqueous solution at a strictly controlled temperature of around 380.degree. C. and no higher, and b) flaking of the melted mass obtained thereby, as it is being rapidly cooled to 150.degree.-160.degree. C. The apparatus for carrying out the process is also disclosed; the apparatus includes a dehydrator-melter oven, a flaker rotating at 10-20 revs per minute and a heat recovery system.

Abstract: An apparatus for the removal of higher and lower volatility organic contaminants from media such as soil including an externally heated screw conveyor having an inlet, an outlet and one or more solid core flights, means for collecting and delivering media contaminated with higher and lower volatility organic contaminants to the screw conveyor inlet, at least one infrared radiation source external to the screw conveyor adapted to heat the media in the screw conveyor to a temperature above which at least one of the contaminants volatilize, and means for venting volatilized contaminants from the screw conveyor.

Abstract: A reaction furnace includes a rotating core within a heated shell, the core and shell defining an active annular zone. An interrupted helical screw carried by the core conveys material from an inlet at one end of the zone to an outlet at the opposite end of the zone. The furnace is operated with the annulus only partially filled. Volatiles rise to a void space at the top of the annulus and are drawn off.

Abstract: This invention aims to offer an external heating rotary furnace for indirectly heating materials such as ore, coke, etc. which are liable to be oxidized, by insulating then from an oxidixing combustion gas atmosphere. The furnace comprises the following members: are reaction chamber (5) in which materials are heated to high temperature, defined by heat resistant ceramic means 4 from the combustion chamber (10) in which the fuel burns out.The fuel burns out in the combusion chamber, and combustion gas does not pass through the reaction chamber (5). Materials to be treated are heated indirectly in the reaction chamber (5) through the insulating ceramic wall (4).According to this invention, materials to be treated can be heated indirectly over 1,400.degree. C. effectively isolated from the combustion gas atmosphere, and inexpensive fuel can be used. Particularly, this invention is useful for the reduction of ores.

Abstract: An incinerator pyrolyzer for continuously burning waste material characterized by a rotating kiln within a furnace chamber for incinerating waste material passing through the kiln. The kiln includes means for introducing reactants for chemically changing ingredients in the waste material. The furnace also including an outlet for dumping the incinerated residue from the kiln and an outlet for any gas generated during the burning.

Abstract: An air cooled rotary kiln collar for use in improving the delivery of preheated charge material from the rotary kiln to the second stage of a multi-stage heating process. Adjustable rate fans circulate air through an annular collar at the discharge end of the rotary kiln to remove heat from the charge material and prevent it from agglomerating and sticking to the kiln.

Abstract: A combustor for burning MSW (municipal solid waste) having a porous wall drum in which burning takes place with combustion air supplied from outside of the drum, in which air driven through the drum into the material being burned is supplied in pulses.

Abstract: In a rotary tubular kiln for carrying out gas-solids reactions, comprising an indirectly heated, rotatable reaction tube with inner baffles which is provided with charging and removing devices for solid and gas inlet and outlet lines, the improvement which comprises forming the baffles as a central tube which is sealed on both sides and runs along the total length of the kiln, and a spiral which is tightly connected to the central tube and also to the outer rotatable tube. Lifting blades are uniformly distributed along the inner periphery of the rotatable tube. The kiln is suitable for carrying out oxidation, reduction, chlorination, roasting, decomposition, catalytic, annealling and/or cooling processes, e.g. the conversion of hematite to magnetite or goethite to iron.

Abstract: A rotary combustor, in which material is burned in a gas porous cylinder, having a sectioned and compartmented wind box permitting selective delivery of air through the burning material, above the burning material, at the start of the burning process, and after burning has been well initiated.

Abstract: Apparatus for dehydrating slurries such as water based drilling fluids heavily laden with drill cuttings and other earth solids comprising a rotating drum which is heated by combustion of a fuel air mixture to generate relatively large quantities of combustion products for heating in an enclosed chamber defined by said drum. The slurry to be dehydrated is injected into the interior of the drum or against the outer sidewall thereof for rapid exposure and substantially flash evaporation of the slurry liquids. An outer housing may be constructed around the drum and in one embodiment the drum is arranged inclined to the horizontal with the slurry introduced into the interior of the drum and the combustion chamber formed between the outer housing and the drum. In another embodiment the combustion chamber is formed on the interior of the drum and the evaporation chamber is formed between the drum and the outer housing.

Abstract: A continuous rotary retort furnace includes an outer shell having first and second ends. A retort assembly extends through openings in the first and second ends. The retort assembly is supported by support devices at both ends external of the shell. The retort assembly is formed of an axial member and a spirally-wound conduit disposed on the exterior surface of the axial member. A drive assembly is coupled to the support device adjacent the first end for rotating of the retort assembly.

Abstract: A rotary kiln is formed by a helical tube secured inside a cylindrical shell, and fitted with flow spoiler baffles between each turn of the helical tube. Inside the helical tube, one solid particle stream flows uphill in the manner of the classical Archimedes screw. Another stream of particles is tumbled by the flow spoiler baffles and flows under gravity downhill through the center of the helical tube, tumbling over the successive convolutions of the helical tube. This downhill flow occurs because the particles collide with the interflute spoiler baffles, tumble and fall off the helical flutes, thus causing the countercurrent flow. A wide range of surface-to-volume ratios of, and heat transfer through, the helical tube may be achieved by a proper design of the relative width of the tube. This helical tube in a drum device provides heat transfer for a varied number of process applications, such as oil shale or tar sands retorting.

Abstract: A rotary kiln includes a cylindrical kiln body supported for rotation about a central axis inclined with respect to a horizontal plane, a cylindrical combustion chamber formed inside the kiln body and extending along the central axis, and a plurality of cylindrical calcination chambers formed inside the kiln body so as to lie parallel with and surround the combustion chamber. The combustion chamber has an outlet at its lower end from which residue produced by combustion of fuel inside the combustion chamber drops for further combustion and/or discharge.

Abstract: An apparatus (14) embodying heat exchange means for treating solid, granular and aggregate materials, and in particular for treating spent, i.e., used, chemically bonded foundry sand. The subject apparatus (14) includes a rotatable first chamber means (16) in which the used foundry sand is preheated while traveling in a first direction therethrough from one end thereof to the other end thereof. From the first chamber means (16) the preheated used foundry sand is suitably conveyed to a thermal reclaimer means (12) for purposes of thermally removing organic matter therefrom. Thereafter, the used foundry sand is conveyed to a second chamber means (44) wherein the used foundry sand undergoes post reclamation whereby any organic matter that may yet remain in the foundry sand is thermally removed therefrom. From the second chamber means (44) the used foundry is made to pass into a third chamber means (52) which is located in surrounding heat exchange relation to the first chamber means (16).

Abstract: A multi purpose three pass drum dryer comprised of two independent and intermeshed systems utilizing an air circulation flowing contrary to the progression of the material through the dryer.

Abstract: A process for the removal of volatile liquid from particulate material employing indirect heating of the particulate material by means of combustion gases resulting from the combustion of sulfur-containing fuel, and further employing purging of the thus heated particulate material by means of combustion gases produced by the combustion of low sulfur fuel to remove vaporized volatile liquid from the particulate material. Also disclosed is a system for performing such removal of volatile liquid from particulate material.

Abstract: A method and apparatus is disclosed for indirectly drying and preheating fine material, in particular, moisture containing coal or the like, comprises, providing a rotary drum which is mounted for rotation and has a plurality of heating tubes extending therethrough, supplying heated cooling gas from a dry coke cooling system to the heating tubes, supplying the moist material to the drum, adjacent the bottom thereof, removing the material from the drum after it has been predried and preheated, and returning or recycling a portion of the predried and preheated material to the rotary drum. The method and apparatus utilizes the heated cooling gas used to cool dry coke in a dry coke cooling plant from high temperatures to below 200.degree. C. It has been found that such heated cooling gas for a selected amount of dry coke is useful either in a series of more than one rotary drum or, to process moist material in a single rotary drum and also generate steam as a byproduct.

Abstract: The thermal efficiency of a dryer is improved by affixing to the shell of the dryer that contains the material to be dried projections which contact a heating medium surrounding the shell of the dryer and protrude into the interior of the shell. Heat is transferred from the heating medium by the projections to the material to be dried that is inside the shell of the dryer.

Abstract: A plant for manufacturing cement clinker from cement raw material includes a preheater first stage separated by a wall into a first chamber and a second chamber. Only raw material is passed through the first chamber while only hot exit gases are permitted to pass through the second chamber. Thus the raw material including any volatile, combustion components are kept isolated from direct contact with the hot exit gases. A heat exchange system is provided to permit the transfer of heat from the hot exit gases in the second chamber to the raw material in the first chamber. The heat exchange system preferably includes self-contained heat pipes extending into both the first and second chambers. The heat pipes contain a fluid medium which aids in the heat transfer as a consequence of cylical changes of the fluid medium from a liquid to a vapor state.

Abstract: An outer cylindrical drum has an inner drum concentrically mounted therein in spaced relationship, to form coextensive outer and inner drying chambers that are connected to a common source of hot exhaust gases from a sugar factory boiler. Raw bagasse is first passed through the outer annular chamber to effect primary drying thereof, and then a portion of the primary dried bagasse is divided from the remainder and is passed through the inner chamber to produce secondary dried bagasse. The conveyance path between the point where the primary bagasse is divided and the inlet of the inner chamber is short in both time and distance to preserve heat in the divided portion, and an entrainment unit is utilized to preheat the divided portion before it enters the inner chamber.

Abstract: A process for drying and/or calcining bulk material in a rotary kiln when hot gases are passed countercurrent to the flow of bulk material thereto, and the bulk material is dried and/or calcined in the rotary kiln is disclosed. According to the invention, the bulk material is dried and/or calcined, as it passes from the feed end of the rotary kiln to the discharge end thereof, by contacting the same with hot gases and thereafter, as the bulk material passes towards the discharge end of the rotary kiln, the bulk material is heated by indirect heat exchange with such hot gases. An apparatus for carrying out such process is also disclosed. The apparatus is a rotary kiln equipped with a centrally disposed tube, disposed axially within the rotary kiln toward the bulk material discharge end of the rotary kiln whereby an annular space is defined between the outer wall of the central tube and inner wall of the rotary kiln.