Showing papers on "Rotary kiln published in 1976"

Portland cement-making and municipal refuse conversion

Abstract: The invention provides a method of incinerating municipal refuse by burning it in a pulverized condition in a rotary kiln with added basic mineral matter, especially Portland cement raw materials, at a temperature sufficient to burn off all combustibles. A stony aggregate is obtained, which in a preferred embodiment is clinker, the rotary kiln being part of a cement plant. Conventional fuel may also be used for firing along with the refuse.

Apparatus for producing cement clinker

Abstract: An apparatus for burning cement raw meal to produce cement clinker which includes a pair of parallel suspension preheaters each adapted to receive cement raw meal and hot spent combustion gas for preheating the cement raw meal. Each of the suspension preheaters discharges preheated raw meal into a single calcining furnace. Combustion takes place in the calcining furnace to produce a calcined raw meal. The spent combustion gases from the calcining furnace are supplied in proportional quantities to each of the parallel suspension preheaters. From the calcining furnace, the calcined raw meal is supplied to a rotary kiln for clinkering the calcined raw meal. Hot cement clinker is discharged into a cooler where the clinker is cooled by passing cooling air upwardly therethrough. The cooling air is heated by the hot clinker and the hottest portion is supplied to the rotary kiln and to the calcining furnace to serve as combustion air. The system is particularly designed for use in converting an existing suspension preheater dry process cement plant to an installation employing a flash furnace to thereby increase the capacity of the plant.

Method and apparatus for making cement with preheater, kiln and heat exchanger for heating combustion air

Abstract: A method and an apparatus is disclosed for producing such as Portland cement from pulverant raw material in a system having at least a preheater and a rotary kiln. The preheater may be of the type having a series of stages each provided by a cyclone dust separator for successively preheating the raw material in a counterflow of kiln waste gases and in which an identified one of the stages discharges a gas flow containing more thermal energy than can be used to advantage in preheating material in the remaining stages through which such gases must pass before dispersing in the surrounding atmosphere. A portion of the gases passing from the identified stage is diverted to a heat exchanger which utilizes the heat energy in such kiln waste gases to heat a clean stream of air. The thermal energy transfer to clean heated air is in turn delivered to the kiln and/or an auxiliary furnace connected to discharge into the kiln waste gas flow between the kiln and the identified stage, and such delivery of clean heated air provides heated combustion air for the burning of fuel in the kiln and/or auxiliary furnace.

Ore-processing systems including rotary kilns

Abstract: A rotary kiln has a main cylindrical processing zone which is coupled downstream and upstream, respectively, to the charge-receiving and charge-withdrawal ports of the kiln through a pair of gas-tight spiral ducts. A reagent to be reacted with the charge is introduced coaxially into the main processing zone, and the spent reaction gases are coaxially removed therefrom. The reaction gas outlet conduit is provided with a hydraulic seal for maintaining a desired value of superatmospheric pressure in the main processing zone, and an additional gas conduit coaxial with the gas withdrawal conduit means is arranged to supply gaseous fuel to a plurality of heating tubes which are disposed in spaced relation through the walls of the main processing zone. Advantageously, the charge is preheated to the reaction temperature in a fluidization furnace or the like disposed upstream of the rotary kiln, and flue dust emitted from the preheating furnace is cleaned and routed into the main processing zone of the kiln along with the reagent. A rotary condenser disposed downstream of the kiln for subjecting the treated charge to an additional process step is provided with a protective atmosphere consisting of the spent reactive gases from the main processing zone of the rotary kiln, such reaction gases having first been cleaned by means of a filter located downstream of the hydraulic seal.

The Effect of Oxygen upon the Rotary Kiln's Production and Fuel Efficiency: Theory and Practice

Abstract: For some thirty years rotary kiln operators have been looking at the possibility of employing tonnage oxygen?high-purity oxygen produced from air separation plants?to improve kiln performance. Experience has shown that because of differences in kilns, such as size, thermodynamic characteristics, and feed material, the response varies from one kiln to another. A mathematical model has now been developed which can, within reasonable limits, predict the effect of tonnage oxygen on any given kiln. Use of the model technique affords the kiln operator the opportunity to evaluate the benefits of oxygen enrichment for his particular operation.

Method of removal of nitrogen oxides, particularly for use in cement raw material burning installation

Abstract: The present invention discloses a method of removal of nitrogen oxides, particularly for the use in a cement raw material burning installation, said method comprising the step of introducing the reduction agent for the removal of nitrogen oxides into the zone, where is heated to about to 800° to 1,100° C of a duct connecting between a furnace such as a rotary kiln and the lowermost cyclone of a suspension type heater system, thereby removing nitrogen oxides produced in the burning furnace.

Method for regulating combustion processes, particularly for the production of cement in a rotary kiln

Abstract: Techniques for regulating calcining processes, particularly the calcining of lime containing materials, which are supplied as pulverized raw material, into cement clinkers in a cylindrical rotary koln, provides that the exhaust gas preheats the raw material and the calcined material preheats the combustion air. The quantity of raw material and the quantity of combustible material, the temperature of the combustion air and of the exhaust gas, as well as the composition of the exhaust gas, and additional parameters of the process are continuously measured and partially controlled. From the continuously measured individual values of the process a characteristic value describing the condition of the process, particularly the supply of heat, is formed, and is utilized to regulate the calcining process.

Process for agglomerating expanded perlite fines

Abstract: Expanded lightly milled perlite fines are mixed with aqueous alkali metal silicates and the wet mixture is dried at temperatures of from 600° F up to 1400° F in a moving air stream to form agglomerates which are useful as filteraids The agglomerates may be heat treated in an indirect fired rotary kiln to further reduce the water solubility, and may be separated into size factions either before or after the heat treatment

Apparatus for cooling particulate material

Abstract: Apparatus for cooling calcined or sintered particulate material discharged from a rotary kiln or other pyro-processing system. The apparatus includes an upright shell adapted to contain the material to be cooled, a mixing hopper arranged within the upper portion of the shell for mixing together particles of the material of different size and air distributing means arranged within the lower portion of the shell for releasing cooling air into the material. The apparatus is configured so that the cooling air moves counter to the direction of material flow.

Burning of pulverous or granular raw materials

Abstract: A method is disclosed for burning pulverous or granular raw material such as cement raw meal in a rotary kiln plant by directing a first flow of raw material to a cyclone preheater, preheating the first flow of raw material in the cyclone preheater, and directing the preheated raw material from the cyclone preheater to a rotary kiln for burning the material in the kiln. The burnt kiln product is directed to a cooler which may be of several types and which communicates with the material outlet of the kiln while a second flow of fresh raw material is directed to the cooler to at least partially cool the burnt kiln product by transferring heat therefrom to the second flow of fresh raw material in the cooler. The method further involves combining the preheated, at least partially calcined second flow of material with the first flow of preheated, at least partially calcined material prior to directing the combined flows to the rotary kiln and thereafter directing the combined flows to the kiln for burning and for subsequent cooling in the cooler. The invention also pertains to a unique kiln plant for practicing the inventive method.

Method for heat treating fine-grain material

Abstract: Fine grained material such as raw cement meal is preheated in a preheater and discharged from the latter into a rotary kiln for calcining and through which hot exhaust gases pass in counterflow to the material. Immediately after introduction of the material to the kiln fuel is sprayed onto the surface of the material and is covered either by additional material from the preheater or by circulation of the material already in the kiln, due to rotation of the kiln at an elevated speed. The fuel is combusted virtually entirely within the kiln and substantially directly at the material without previous gasification of the fuel.

Controllable distribution system for rotary kiln

Abstract: Apparatus for controlling the delivery of fuel and air to a rotary reduction kiln wherein both the fuel and air flow through the same fluid distribution nozzle. Separate fuel and air valves control the flow through the nozzles. Two separate means are provided about the kiln for operating each valve as the kiln rotates. Each of these means is individually adjustable to a first position where the valve setting is sequentially altered as the kiln rotates and to a second position where the valve setting is unaltered as the kiln rotates.

Planetary cooler system for rotary kiln plant and the like

Abstract: A planetary cooler system is disclosed for cooling hot cement clinker exiting from a rotary kiln having a plurality of cooler tubes mounted in planetary fashion there-about and being adapted to receive material from the rotary kiln into their inlet end portions. A material outlet casing communicates with the planetary cooler tubes and is adapted to receive at least partially cooled hot material from the outlet portion of each cooler tube when its rotational position is at or near its uppermost position. The outlet casing defines two shafts joined at their upper ends and configured and adapted to receive the partially cooled cement clinker from the tubes for passage down through the shafts to cause the outlet casing to act as a shaft cooler, while at least one ventilating device blows or draws cooling air through the casing to provide further cooling of the clinker preferably countercurrently to its passage therethrough. The invention also relates to a rotary kiln plant incorporating the cooler system.

Method for the heat treatment of fine-grained materials containing alkali compounds

Abstract: A method for the heat treatment of fine-grained materials containing alkali compounds which liquify at critical temperatures comprises pre-heating the materials and discharging them to a rotary kiln in counterflow to the kiln exhaust gases, and introducing cooling air to the kiln in such quantity and at such temperature as to reduce the temperature of the exhaust gases to a level lower than that required for the compounds to liquify.

Cement making apparatus including preheater, kiln, cooler and auxiliary furnace

Abstract: An apparatus is disclosed for producing such as Portland cement from pulverant raw material having a preheater, an auxiliary furnace 22, a rotary kiln 2, a cooler, and a single blower connected to the top of the preheater to draw air and combustion gases through the kiln, auxiliary furnace and preheater. Preheater receives waste gas from the rotary kiln for flow through first, second, third and fourth level cyclones, with the first level cyclone(s) C 1 being at an elevation higher than the kiln and the second, third and fourth level cyclones (C 2 , C 3 and C 4 ) each being at successively higher elevations. The auxiliary furnace 22 is preferably at the approximate level of the second level cyclone C 2 . The auxiliary furnace 22 is fed pulverant material from third level cyclone C 3 and discharges pulverant material to a flue leading from the kiln to first level cyclones C 1 , with both such feed to and discharge from the auxiliary furnace proceeding under the influence of gravity without the need for a second blower to pressurize air from the cooler to the auxiliary furnace as has been necessary with arrangements of such systems known to the prior art before the present invention.

Method of heat treating raw materials and rotary kiln plant therefor

Abstract: A method is disclosed for burning alkaline raw materials in an inventive rotary kiln plant. According to the method, cold atmospheric air is introduced tangentially into a circular chamber mounted either within, or adjacent to, the raw material inlet end of the kiln such that a circulating stream of cold air is produced in the chamber around a stream of exhaust gases passing from the kiln to the chamber. A part of the exhaust gases are thereby cooled by the cold air, and alkali vapors therein are condensed out of, and onto, dust particles in the exhaust gases. The alkaline-coated dust particles are thus subsequently discharged from the chamber. The invention also relates to a rotary kiln plant for practicing the inventive method.

Method for producing ferro-alloys

Abstract: An improved method and apparatus for producing ferro-alloys from ore in which an ore is first mixed with a solid reducing agent, preheated and pre-reduced in a rotary kiln, and smelted in an electric furnace, in which the pre-reduced ore is heated by a burner provided in the electric furnace where it is also reoxidized. The ore is also heated in the rotary kiln by recycled gas.

Aggregates manufactured from waste materials

Abstract: Aggregates can be produced from diverse waste materials such as fly ash, waste clay, foundry effluent, phosphate slime, and municipal refuse. Finely divided particulates are characterized for the ability to form an aggregate using either a rotary kiln or traveling grate sintering machine. If the material does not possess the required characteristics for making an artificial aggregate, various additives can he used to upgrade the processing parameters. Residues from incineration of municipal refuse can be used either upon separation and classification, or after incineration. Qualities for a good concrete aggregate are strength, particle shape to promote good workability, low water absorption, and chemical and physical stability.

Method of heat treating fine granular material

Abstract: A chamber which forms a material inlet and an exhaust gas outlet at one end of a rotary kiln has an inclined bottom arranged to cause preheated fine material deposited thereon to slide by gravity into the end of the rotary kiln. A dense stream of fine granular material is deposited on such inclined surface, and fuel in finely divided form is introduced into the dense stream of material flowing down the inclined surface to cause the fuel to become intimately mixed with the material. Gas is discharged from the kiln in contact with the stream of material as such a velocity as to entrain a substantial proportion of such stream, the temperature and composition of the gas being such as to cause combustion of the fuel mixed with the entrained material.

Rotary kiln plant

Abstract: A plant is disclosed for heat treating pulverous raw material such as cement raw meal prior to a final sintering process in a rotary kiln. The plant includes a rotary kiln having an upper material inlet end portion for the reception of preheated cement material and a lower material outlet end portion for exiting the final sintered kiln product. A multi-stage cyclone string preheater having at least a first stage for receiving the cement raw meal has a last stage communicating with the upper material inlet end portion of the kiln. A smoke chamber connects the upper material inlet portion of the kiln with the preheater, and a scoop chamber connects the kiln with the smoke chamber. The scoop chamber is adapted to receive preheated, at least partially calcined raw material from at least one preheater stage other than the last stage. The cement material received in the scoop chamber is dispersed so as to be suspended in the gases exiting the kiln and directed through the smoke chamber to the last stage of the associated preheater string. The preheated, at least partially calcined cement material is then directed from the last stage of the preheater string to the upper material inlet end portion of the kiln at a location upstream with respect to the kiln exiting gases, off the location of the dispersing means, so as to pass down through the kiln for further heat treatment.

Planetary cooler system for rotary drums such as kilns

Abstract: A planetary cooler system is disclosed for cooling hot pulverous or granular material produced and exited from the discharge end of an inclined rotary drum such as a rotary kiln. A plurality of cooler tubes are mounted in planetary fashion about the material discharge end of the kiln with the axis of each tube in parallel, or approximately parallel, relation to the axis of the drum. A conduit communicates the discharge portion of the rotary drum with each cooler tube for the passage of hot material therethrough in countercurrent to preheated cooling air passing from the cooler tube to the drum to serve as combustion air. The conduit is so positioned as to divide each cooler into at least two sections, a first section of the cooler tube extending away from the conduit in a direction generally upstream of the flow of material inside the kiln, and the second section extending away from the conduit in a direction generally downstream of the flow of material in the kiln. Both sections of each cooler tube have a material outlet end portion for discharging hot material such as cement clinker, and each outlet end portion has means associated therewith to permit the entrance of cooling air therein and to discharge hot material from the cooler tube section. The arrangement permits a greater capacity to handle relatively large volumes of material from the rotary kiln without altering the load to which the kiln sections are subjected. Also the necessity to increase the number of cooler tubes or diameters of the components involved is also avoided.

Method and apparatus for burning pulverulent materials

Abstract: A method of burning pulverous or granular material in a plant including a suspension preheater and a rotary kiln having an integrally mounted planetary cooler for cooling the burnt material exiting from the kiln by means of air subsequently used for combustion and preheating in the plant. The method comprises directing the heated cooling air from the planetary cooler into the rotary kiln, dividing the heated cooling air into two streams, directing the divided cooling air out of both ends of the kiln in its divided streams, directing at least one of the streams of the heated cooling air into the rotary kiln and utilizing the stream as combustion air in the rotary kiln, thereafter directing the stream as part of a waste gas out of one end of the kiln to the preheater for use in preheating the raw material fed into said preheater, drawing the other stream of heated cooling air out of the other end of the kiln and directing said other stream of cooling air to the suspension preheater for use in preheating raw material fed into said preheater. An apparatus for practicing the method of the invention is also disclosed.

Rotary kiln apparatus

Abstract: PURPOSE: To remove gap caused by thermal strain etc. so as to prevent leakage of radioactive material through around the shaft of rotation by complete seal of annular sealing surface formed between the outer circumference of a shaft corresponding to the rotary cylinder of the apparatus body and a fixed housing. COPYRIGHT: (C)1978,JPO&Japio

Process for the two-stage reduction of iron ore in a rotary kiln

Abstract: A process for the two-stage reduction of iron ore in a rotary kiln, which is an improvement on US Pat No 3,833,355 A layer of reducing agent such as coke is held against the side wall of a reactor that rotates about its vertical axis, by centrifugal force and its own friction The next inner layer is a layer of iron ore The improvement over the earlier patent is that reduction is conducted in two stages comprising a first relatively low temperature stage of 1 to 4 hours at 700° to 1100°C, which does not melt the ore, and a second relatively high temperature stage of 05 to 15 hours at 1450° to 1550°C, with removal of the reduced carburized liquid iron from the bottom of the reactor during the second stage

Fuel and feedstock from refuse

Abstract: Pyrolysis processes for the conversion of municipal solid waste to useful material are options to current disposal methods. Pyrolysis has the potential for volume and mass reduction and energy recovery. Fuel/feedstock products from a pyrolysis reaction system can be liquid, solid, and/or gas with the estimated heating values of 10,000 to 11,000 Btu/lb, 6,000 to 9,000 Btu/lb, and 100 to 600 Btu respectively. Shaft, rotary kiln and fluidized bed reactor types are described. Commercial pyrolysis processes are also discussed. (ND)

Conversion of Existing Cement Kilns to Flash Calciners

Abstract: Contemporary cement kilns equipped with a suspension preheater provide for efficient operation with the lowest specific heat consumption. The incorporation of a flash calciner reduces the fuel requirement of the rotary kiln, thereby improving refractory life and reducing nitrogen-oxide emissions. The benefits of suspension preheat and flash calcination can be achieved in existing wet or dry process plants. Such modifications can increase kiln production while reducing the specific heat consumption. Several existing long wet and long dry kilns and suspension preheater kiln systems have been modified to flash calciner configurations.

Rotary kiln drive - entraining rollers driven by hydraulic motors with clutches and brakes ensure self-adjustment

Abstract: The design reduces the space requirements for the kiln drive as well as cost and the wear due to the individual low-velocity motors coupled directly to the rollers. The hydraulic motors are fed by a single source and the difference in diameters of the individual drive rollers (8) for rings of the kiln are readily compensated by the motors, while brake (26) controls the stoppage. The drive permits an easy setting of the position of salt or metal discharge spouts with the plate-type brake operated by a separated hydraulic line.

Cement making plant - comprising rotary kiln with cyclones, connected in series, the final two having extra cyclone connected to their joining duct

Abstract: Cement making plant comprising a rotary kiln and a preheater has a series of cyclones joined together and to the kiln by ducts so that the smoke leaving the kiln passes successively through the cyclones giving heat exchange in countercurrent. The novelty is that an extra cyclone is provided, the entry to which is connected to the duct joining the last and penultimate cyclones of the preheater. The exit is connected to the entry to the heating fluid circuit heating a boiler. The extra cyclone is arranged above the last-but-one cyclone. The arrangement permits the supply of all the necessary drying heat in every case, while maintaining constant the flow of smoke in the cyclones of the preheater and in the extra cyclone.

Method and equipment for regeneration of active carbon

Abstract: PURPOSE:To regenerate the active carbon continuously by the inner-and outerheating rotary kiln.

Method for reducing the volume of drying or burning residue of sludge formed at treatment of waste water from the plating step

Abstract: PURPOSE:To reduce the volume and weight of sludge formed at the treatment of waste water from the plating step by treating the sludge in a drying equiipment such as a rotary kiln or a burning equipment.