Abstract: A heating device for a rear wall of a tumble dryer is disclosed, wherein the heating device includes an electric heating arrangement which may be formed of heating coils. A bypass airflow which is not directly heated by the heating arrangement flows in addition in the housing so that the heat loss through the housing is reduced.

Abstract: To provide a device for removing radioactive cesium from waste material containing radioactive cesium, doing so at low energy and in a dependable manner. The removal device 1 for radioactive cesium is provided with: a rotary kiln 41 which is provided with a burner 41b supplying from the kiln outlet an organic matter O3 contaminated with radioactive cesium, and an inorganic matter charging port 41a supplying from the kiln inlet inorganic matter S4 contaminated with radioactive cesium, and which is employed to burn the organic matter O3 together with the inorganic matter S4; and a recovery device cooling tower 51, a cyclone 52, a bag filter 53 for recovering cesium that has volatilized in the rotary kiln. A drying/crushing device (dryer 21, crusher 22) for drying and crushing the organic matter O1 prior to charging the radioactive cesium-contaminated organic matter to the rotary kiln can be provided.

Abstract: A supply tube assembly has a central longitudinal axis, a first end and a second end and includes a supply pipe extending in parallel with the central longitudinal axis from the second end of the supply tube assembly to the first end of the supply tube assembly. The supply pipe is open to form a pipe outlet at the first end. The supply pipe is configured for transporting solid particles carried by a fluid from the second end to the pipe outlet. A ramp arranged inside the supply pipe at the pipe outlet and pivotably arranged such that the inclination of the ramp in relation to the longitudinal axis is adjustable by pivoting the ramp about a pivot axis which is perpendicular to the central longitudinal axis, with the ramp extending from said pivot axis towards the pipe outlet.

Abstract: In the method according to the invention for operating a cement plant, the raw meal is preheated in a preheating zone, the preheated material is precalcined in a calcining zone and the precalcined material is finally sintered in a sintering zone. The cement plant is operated in such a manner that the precalcined material which is supplied to the sintering zone has an SO3 concentration of at least 5.5% by mass and a CaSO4 proportion of at least 75%, preferably 90%, of the total salt content.

Abstract: To produce cement clinker by baking of raw meal in a kiln, use is conventionally made of a raw meal preheater in which the heat of the flue gas emerging from the kiln is transferred to the raw meal. In order to remove impurities which accumulate in circulation between the kiln and the raw meal preheater, a part of the flue gas is extracted from the kiln, bypassing the raw meal preheater. The heat generated during the baking of cement clinker can be used particularly efficiently if the flue gases extracted and diverted past the raw meal pre-heater are used in a boiler to generate hot steam which can subsequently be expanded in a turbine.

Abstract: A method for burning raw materials by which method the raw material and a secondary fuel are separately introduced to one and the same rotary kiln in which the raw material as well as the secondary fuel are heated by gases formed by burning of a primary fuel in the rotary kiln so that the secondary fuel is converted to gases and solid matter in the form of combustion residues such as ashes and coke. The secondary fuel during the process of conversion to gases and solid matter is kept separate from the introduced raw material, which may ensure that the secondary fuel and hence the locally reducing zones and major areas with reducing conditions are brought into minimum contact with the raw material.

Abstract: A system for the thermal preparation of reclaimed road material containing PAHs, or of oil sludge having a loading station for pre-comminuted reclaimed road material or oil sludge, a rotary kiln in which the reclaimed road material or the oil sludge is burned, while oxidation air is fed in, a dust separator to which the flue gases produced in the rotary kiln are fed, an after-burner to which the flue gases leaving the dust separator are fed, and a filter to which the flue gases arising in the after-burning means are fed. These components are divided into a plurality of modules, each of which includes a weight and dimension such that each may individually be transported using conventional road transport means, in particular low loaders or heavy goods vehicles.

Abstract: The present invention relates to a method and an arrangement for burning lime mud into lime in a lime kiln The lime mud flows counter-currently to flue gases from a feed end to a firing end and the fuel used is flue gas that is produced by gasifying a fuel in the presence of combustion air in a gasifier. The combustion air for gasification is preheated with heat generated in lime mud combustion. The arrangement is provided with a conduit between the lime kiln and the gasifier for leading air from the lime kiln into the gasifier as combustion air. At least a portion of the combustion air for gasification is preheated with heat generated in the lime mud combustion so that air is led into cooling of lime obtained in the combustion and further into the kiln, from or through the firing end of which air is taken into the gasification.

Abstract: The invention relates to a process for manufacturing cement clinker in a plant having a cyclone preheater, a precalcination reactor, a rotary furnace and a clinker cooler. In the process, the flue gases from the furnace are conducted to the precalcination reactor, or even to the cyclone preheater. According to the invention, the precalcination reactor is fed with an oxygen-rich gas, the nitrogen content of which is less than 30%, constituting the sole oxygen source for said reactor, and a portion leaving the cyclone preheater is recycled into the plant so as to obtain a suitable flux necessary for suspending matter in said preheater, while the other portion, rich in carbon dioxide, is adapted for the purpose of a treatment for limiting the amount of carbon dioxide discharged into the atmosphere, such as particularly sequestration.

Abstract: A rotary kiln includes a stationary burner and at least one electrode configured to apply an electric field and/or voltage to a flame supported by the stationary burner. The electric field may contain the flame and/or accelerate combustion to shift most heat transfer from the flame from radiation heat transfer to convective heat transfer.

Abstract: A skewer system comprises a skewer rod that holds tires in suspension during an incineration process where the tires are burned for fuel in a kiln such as a cement kiln or a lime kiln. In certain implementations, the skewer system also comprises a fuel advancing system to advance tires loaded onto the skewer rod into the heated gas in a stationary heat transfer station of the kiln. In further exemplary implementations, the skewer system comprises a mechanism to recover wire remnants from incinerated tires, the wire can be cut off the skewer and dropped into the kiln, or the wire itself can be burned off.

Abstract: This application concerns methods and apparatus for use in industrial waste recovery operations such as recovery of non-consumed chemicals in industrial processes, with recovery of quick lime in a wood pulp process being an example. In some embodiments, methods comprise baking lime sludge in a kiln and controlling a temperature in a calcining zone of the kiln to be above about 2250° F. to vaporize sodium contained in the lime sludge. Interaction of the vaporized sodium with SOx can deter accumulation of one or both of CaCO3 and CaSO4 on one or more inner surfaces of the kiln. In some embodiments, lime sludge can be rinsed to generate a filtrate comprising dissolved NaOH, and the filtrate can charge a scrubber for removing SOx from an exhaust from the kiln. Embodiments of co-fired burners for heating such kilns by burning petroleum coke and natural gas are also disclosed.

Abstract: A method is described for reducing NOx emissions and improving energy efficiency during mineral processing in a rotary kiln. The method comprises injection of air with high velocity/high kinetic energy into the kiln to reduce or eliminate stratification of kiln gases. The method can be applied to mix gases in a rotary kiln vessel or in a preheater/precalciner vessel.

Abstract: A method for producing cement clinker in a plant that includes: a first cyclone preheater and a second cyclone preheater for preheating first and second portions of a raw material, respectively; a precalcinator using a combustion gas for burning a fuel, the fumes released by the precalcinator being directed to the second cyclone preheater; a rotary furnace provided with a fuel burner, the fumes released by the rotary furnace being directed to the first cyclone preheater; and a clinker cooler that blows cooling air across the clinker at the outlet of the rotary furnace. According to the method, the precalcinator combustion gas contains between 90 and 100 vol % of oxygen. The precalcinator may consist of a fluidized bed, the fluidization gas being the combustion gas. The invention also relates to a plant as such.

Abstract: A gas-heated laundry dryer having a heating device. The heating device includes a gas burner, a valve with a gas nozzle configured to supply primary air for formation of a flame and a tubular heating channel configured to enclose the flame. The tubular heating channel includes an inlet opening configured to receive secondary air as combustion air and an outlet opening configured to receive tertiary air mixable with hot gases of the burner. The outlet opening is connected to a process air duct of the laundry dryer. An annular baffle member is disposed in the outlet opening of the heating channel and configured to center, by the secondary and tertiary air, at least one of the flame and a hot air stream in the channel.

Abstract: The invention relates to a method for calcination of a material in which said material is heated by contact with a heat source essentially generated by means of a flame produced with at least one flow of fuel and primary air and a flow of secondary air, the flame comprising a first combustion zone with a temperature below 1500° C. and a second combustion zone with a temperature above 1500° C., where at least one flow of at least one inert gas is injected into the flame at the beginning of the second combustion zone and/or at least one flow of oxygen or a gas enriched in oxygen is injected into the second combustion zone.

Abstract: A kiln comprising a substantially cylindrical drum (11) supported from a support structure for rotation about its central axis whereby the drum is supported such that the central axis is generally horizontal and whereby the drum is configured and/or arranged such that rotation of the drum will cause fluid particulate material to flow from one end (13) to other end (15). The one end being associated with a fuel inlet (33) and the other end being provided with a discharge (37) for combustion products and heat. The inner face of the side wall of the drum is provided with a plurality of ports (29) which are located at spaced intervals along and around the interior of the drum and which open into the interior of the drum, the one end being closed by an end assembly (23) fixed relative to the support structure whereby the one end is in close abutting relationship with the end assembly. An opening (25) is provided in the end assembly, the opening connected to a source of air (31).

Abstract: Disclosed is a process for reducing metallic oxide or sulfide materials in a rotary kiln and a rotary kiln for reducing such materials. The materials are heated in a reducing atmosphere as they travel along the axial length of the rotary kiln. The materials are discharged from the kiln at a discharge point in the kiln away from its lower material outlet end, wherein the temperature within the kiln at said discharge point is greater than the temperature at the lower material outlet end.

Abstract: A NOx suppression apparatus is configured for use with a burner that injects fuel into a stream of process air flowing into and through a rotary kiln. The apparatus comprises a premix injection system that forms a premix of fuel gas and air, and injects the premix into the stream of process air upstream of the burner port. This enables premix products of combustion to suppress the production of NOx by vitiating a combustion air portion of the process air before the combustion air portion combusts with fuel injected from the burner port.

Abstract: In order, for operating the lance burner of a rotary tubular furnace for the production of cement clinker from calcined raw cement meal, to provide an automated regulation method which is optimized in terms of the configuration of the burner flame for all types and quantities of fuels used, according to the invention a regulation method is proposed in which the characteristics of the burner flame are used as measurement variables, and the measurement variables are delivered to a controller which can vary at least three different manipulated variables of the burner, such as the spatial outflow angle and the swirl momentum of the swirled primary-airstream and/or the angle of divergence of the primary-air/jet-air jets emerging from individual nozzles and/or the velocity of emergence and/or swirl component of a stream of fragmentary alternative fuels or secondary fuels which is blown through the burner.

Abstract: To provide a cement clinker production line with a calcining stage which is connected upstream of the rotary tubular kiln and has an integrated calcining combustion chamber, with formation of a CO-containing reduction zone whose size and length and reduction potential can be adapted with simple means to different NOx contents contained in the rotary kiln exhaust gas and/or different types of material and pellet sizes of the secondary fuels used in the calcining combustion chamber, the calcining combustion chamber may have an upper, raw-meal-free reducing zone with a feed for secondary fuels arranged at the upper side of the combustion chamber, and first tertiary partial airstream with sub-stoichiometric fuel combustion for the purpose of gasifying the secondary fuels, and the combustion chamber may have a lower zone, the inflow for at least one raw meal partial stream and one second tertiary partial airstream being arranged in the junction region of the upper raw-meal-free, reducing zone and the lower zone, t

Abstract: The invention provides a process for the production of cement which comprises the calcination of calcium carbonate-containing raw meal in a calciner heated by combustion of a carbon-containing fuel with a gas comprising oxygen and from 0 to 80% by volume of carbon dioxide, and substantially free of nitrogen, and isolating the gas produced by combustion and calcination in the calciner.

Abstract: A fine dust removal system for a rotary lime kiln includes a preheater adjacent the charging end of the kiln and a housing adjacent to and communicating with kiln charging end, such that a major portion of not off-gases containing solid particulates are diverted to the preheater and a minor portion thereof directed into the housing. At least a portion of the solid particulates is separated from the hot off-gases in the housing, while the hot off-gases leaving the housing, after solid particulate removal, are directed into the preheater.

Abstract: The present invention relates to a coffee roaster that roasts coffee beans by using heat emitted from a gas burner and a ceramic dome and has a hot water tank supplying hot water to coffee, wherein a rotary shaft rotating a roasting drum is rotatably supported on a base groove formed on the top surface of a base rod and a support groove formed on the bottom surface of a support rod, thereby permitting the rotary shaft to be removably mounted thereon, and wherein a heat-absorbing pipe is disposed in a high-temperature space between the gas burner and the inner wall surface of the ceramic dome, so as to allow a heat transfer medium to be forcedly circulated therethrough, and a heat-generating pipe disposed on a lower portion of a hot water tank in such a manner as to be submerged into the water in the hot water tank.

Abstract: A method for feeding lime mud into a lime kiln including a rotary kiln shell having an interior between a first end wall and a second end wall, the method including: feeding the lime mud into a flue gas flow in the interior of the rotary kiln shell or in close proximity to the shell to pretreat the lime mud; separating the pretreated lime mud from the flue gas flow; conveying the separated lime mud into the lime kiln, and calcining the separated lime mud in the lime kiln.

Abstract: A method is described for reducing NOx emissions and improving energy efficiency during mineral processing in a rotary kiln. The method comprises injection of air with high velocity/high kinetic energy into the kiln to reduce or eliminate stratification of kiln gases. The method can be applied to mix gases in a rotary kiln vessel or in a preheater/precalciner vessel.

Abstract: A method is described for reducing NOx emissions and improving energy efficiency during mineral processing in a rotary kiln. The method comprises injection of air with high velocity/high kinetic energy into the kiln to reduce or eliminate stratification of kiln gases. The method can be applied to mix gases in a rotary kiln vessel or in a preheater/precalciner vessel.

Abstract: A gas-heated laundry dryer having a heating device. The heating device includes a gas burner, a valve with a gas nozzle configured to supply primary air for formation of a flame and a tubular heating channel configured to enclose the flame. The tubular heating channel includes an inlet opening configured to receive secondary air as combustion air and an outlet opening configured to receive tertiary air mixable with hot gases of the burner. The outlet opening is connected to a process air duct of the laundry dryer. An annular baffle member is disposed in the outlet opening of the heating channel and configured to center, by the secondary and tertiary air, at least one of the flame and a hot air stream in the channel.

Abstract: The invention relates to a method for calcination of a material in which said material is heated by contact with a heat source essentially generated by means of a flame produced with at least one flow of fuel and primary air and a flow of secondary air, the flame comprising a first combustion zone with a temperature below 1500° C. and a second combustion zone with a temperature above 1500° C., where at least one flow of at least one inert gas is injected into the flame at the beginning of the second combustion zone and/or at least one flow of oxygen or a gas enriched in oxygen is injected into the second combustion zone.

Abstract: Method and apparatus for pneumatically drying thickened lime mud and feeding the dried thickened lime mud to a lime reburning kiln. The thickened mud is pneumatically dried via the action of flue gas emanating from the lime reburning kiln. The dried, thickened lime is separated from the flue gas in a cyclone separator. A process loop controller determines the temperature of the separated lime and, in response, controls the feed rate of lime fed to the pneumatic dryer to ensure that the dryer possesses the requisite latent heat needed to dry thickened lime therein. In one embodiment, the feed rate of lime fed to the thickener is adjustably controlled which, in turn, adjustably varies the flow rate of the thickened mud to the dryer.

Abstract: In a kiln whose interior is heated by combustion with oxidant having a higher oxygen content than air, streams of staging oxidant are fed into the space between the combustion zone and the inner surface of the kiln, and the stoichiometric ratios and amounts of oxygen in the combustion zone and in the overall operation of the kiln are adjusted to provide control or reduction of NOx formation while maintaining or increasing productivity of the kiln.

Abstract: A cement product is disclosed. The cement product includes clinker defined by a feedstock material and a ladle metallurgical facility slag material derived from a ladle metallurgical facility steel production system. A system and method for manufacturing clinker is also disclosed.

Abstract: A method is described for reducing NOx emissions and improving energy efficiency during mineral processing in a rotary kiln. The method comprises injection of air with high velocity/high kinetic energy into the kiln to reduce or eliminate stratification of kiln gases. The method can be applied to mix gases in a rotary kiln vessel or in a preheater/precalciner vessel.

Abstract: A heating configuration for a drier, particularly for a laundry drier, has a burner with a burner head, a first heating channel with an inlet opening and an outlet opening, and a second heating channel with an inlet opening and an outlet opening. The cross-sectional area of the second heating channel is greater than the cross-sectional area of the first heating channel. The burner head projects into the inlet opening of the first heating channel and the outlet opening of the first heating channel projects into the inlet opening of the second heating channel. The first heating channel is disposed in the lower section of the second heating channel so that a uniform temperature distribution is achieved in the second heating channel.

Abstract: A controller for a kiln plant, typically a cement plant, has a thermodynamic controller which measures a number of variables including the kiln hood temperature and one or more output gas concentrations, and controls the fuel input to the kiln to maintain the hood temperature within a desired range and a main impeller of the kiln to maintain the measured gas concentrations within a predetermined range. The invention includes a quality controller wich controls the amount of 3CaO.SiO2 present in clinker produced by the plant. The controller comprises an inner controller which controls free-lime content in the clinker and a thermodynamic outer controller.

Abstract: The invention in its various embodiments includes an apparatus and a method for improving combustion in a cement kiln system. The apparatus in one embodiment includes a precalciner and an oxygen source coupled to the precalciner. The method in one embodiment includes introducing oxygen into the precalciner of a cement kiln system.

Abstract: A warp resistant fuel feed door assembly for use in injecting supplemental fuel into a high temperature combustion chamber such as a rotating cement kiln without substantial loss of heat or combustion gases. The apparatus, which is positioned on the exterior side of a fuel passage transecting the wall of a rotating kiln, opens to receive fuel and then seals during the balance of the rotation of the kiln. Warping, bearing fracture, shaft distortion and jamming due to exposure to extreme heat and cooling are minimized by the sectional construction of the doors. The door includes a plate positioned over the mouth of the passage, a plurality of support arms attached to the plate and a hinge shaft attached to the arms. Stresses on the door structure from inconsistent expansion of the plate are reduced due to symmetrically spaced oblong and oversized bolt attachment bores in the support arms. Synchronous opening of the feed doors is achieved by levered rotation of the hinge shafts by an electric motor.

Abstract: A rotary kiln for calcination of light aggregate cement comprises a calcination kiln body, a heavy-oil combustion device, and a cooling device, wherein the calcination kiln body is formed in a U-turn for saving construction site and is composed of a feeding entrance at its upmost end, a product exit at the lowest end, and a plurality of revolving segments varied in caliber by segment so as to raise the calcination efficiency, save construction expenditure, and meet environment requirements.

Abstract: Combustion process especially applicable to cement works, in which process it is desired to use fuels which are difficult to ignite. To do so, a flame comprising a primary zone and a secondary zone is created. The hot primary zone is created using an oxy-fuel flame, which makes it possible to preheat the fuel which is difficult to ignite so as to raise it to the suitable temperature in the secondary zone where it burns, with air, in order to create the main flame. Applications: cement, metallurgy, glass, etc.

Abstract: A kiln fuel system and method for producing cement. The system includes a tank for storing a fuel and a suction heater for drawing and preheating the fuel from the tank. A pressure station pressurizes the preheated fuel and a heater heats the preheated and pressurized fuel. A burner receives the fuel from the heater and ignites the fuel to form a flame and heat the concrete. The fuel is preferably a bitumen/water fuel mixture. A burner valve train is provided for regulating an amount and mixture of fuel and air supplied to the burner, preventing the flow of fuel to the burner upon detection of a predetermined condition, regulating an amount of heated and pressurized fuel supplied to the burner and providing a source of pressurized air for controlling a size of the flame produced by the burner. A slop tank is connected to the tank for receiving the fuel upon detecting a temperature of the fuel is above a predetermined value in the suction heater or above a predetermined pressure in the pressurizing station.

Abstract: The invention provides a method and apparatus for charging a raw material and a carbonaceous material, in which a reduced product generated on a hearth can be quickly melted for reliable separation into a metal and slag, and the metal and the slag can be easily discharged out of a furnace as individual small agglomerates. With the charging method and apparatus, when charging the raw material and the carbonaceous material onto the moving hearth of the moving hearth furnace, the carbonaceous material is first charged onto the moving hearth to form a carbonaceous material layer thereon. The raw material or a mixture of the raw material and a carbonaceous material is then charged onto the carbonaceous material layer to form a raw material layer thereon. A projection is then pressed against the raw material layer from above, thereby forming a plurality of recesses in the surface of the carbonaceous material layer.

Abstract: A method of disposing of undesirable chemical compounds in waste dust generated in a first kiln in the manufacture of cement clinker by using the dust and slag as the feedstock material to a second kiln, heating the feedstock material in an oxidizing atmosphere, and raising the heat sufficient to diffuse the waste dust and the slag to form a hydraulic product such as cement clinker and lime but insufficient to volatilize previously precipitated chemical compounds in the feedstock material.

Abstract: A kiln is provided with oxidant injection locations upstream of air blowers which blow air into the kiln. The addition of oxygen into the kiln increases the cooling capacity of a clinker cooler, and enhances combustion in the kiln.

Abstract: In order to create, for cement clinker production lines, a calcinator that is connected upstream from the rotary tubular kiln and is equipped with two firings, which enables on the one hand a high-grade calcinated raw meal and on the other hand an exhaust gas with very low NOx emissions, as well as a burning that is as complete as possible of remaining CO-containing NOx reduction zones, it is provided that a combustion point with sub-stoichiometric fuel combustion be arranged both in the rotary kiln exhaust gas ascending line and also in the cooler outgoing air line which form a first and section portion, respectively, of the calcinator and that downstream in a flow direction of the suspension, additional combustion air discharges into the calcinator which combustion air is branched off from the tertiary air line coming from the clinker cooler via at least one branch line.

Abstract: A method of burning tires in a horizontally rotating combuster includes the steps of loading the tires into a rotating combustion chamber through a traveling air lock and burning them until they are reduced to ash; enhancing combustion by tumbling the burning tires in a tapered rotating chamber while adding preheated draft air; controlling the intake draft air using thermal expansion of the rotary combustion chamber to activate the draft control valve; advancing the residual ash with each successive revolution of the combustion chamber by use of angled flights on the inner surface of the chamber to an afterburner for completion of the combustion and disposal of the ash.

Abstract: A kiln adapted to recycle kiln dust includes a recycle dust pipe in fluid communication with an oxidant stream to increase the concentration of oxygen in the fluidized recycle dust before the recycle dust stream is directed into the kiln flame. Increasing the oxygen concentration in the recycle dust stream improves the efficiency of the recycling process. A supplemental fuel stream may be introduced into the recycle dust stream to provide an additional flame to preheat the recycle dust stream before the recycle dust stream is directed into the kiln flame.

Abstract: A device for the combustion of solid fuel in the form of granules, pellets, chips or other fragmented or finely divided form, comprising a rotary reactor drum (1), which forms the main combustion chamber (13) and has a rear end wall (65) and at the opposite end an outlet (3) for combustion gases to a boiler part for heat transfer to water-cooled surfaces, for example, or other heat-absorbing means, an inlet (55) for combustion air to the main combustion chamber (13), means (40) for feeding fuel through the rear end wall (65) of the reactor drum and means for rotating the reactor drum around its center axis (2). Inside the main combustion chamber (13), in its rear part, is an inner, smaller drum (60), which is coaxial with the reactor drum (1) and has a perforated jacket. At least the bulk of the fuel is disposed to be fed into the inner, smaller drum (60) and from this to the surrounding main combustion chamber (13).

Abstract: A method of disposing of undesirable chemical compounds in waste dust generated in a first kiln in the manufacture of cement clinker by using the dust and slag as the feedstock material to a second kiln, heating the feedstock material in an oxidizing atmosphere, and raising the heat sufficient to diffuse the waste dust and the slag to form a hydraulic product such as cement clinker and lime but insufficient to volatilize previously precipitated chemical compounds in the feedstock material.

Abstract: Superior heat transfer in a kiln is achieved by the use of at least one injector which injects both an oxidant, preferably containing oxygen, and a secondary fuel into the kiln. The injectors are provided so that the energy resulting from the combustion of the different fuels in the kiln heats specified regions of the kiln, without causing hot spots on the refractory walls. A firing scheme is described for the oxygen and fuels which allows an increase in the amount of heat released toward the load, resulting in significant increases in kiln efficiency and production. Low quality fuels may be used, as well as using and/or recycling more insufflated dust, without an adverse effect on the main flame.

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.