Showing papers on "Rotary kiln published in 2000"

Pyrolysis process for reclaiming desirable materials from vehicle tires

Abstract: A process and system for the recovery of desirable constituent materials from vehicle tire pieces through pyrolysis. The system includes a pyrolysis section that is divided into a plurality of individual heating zones. Each of the heating zones is heated to a distinct operating temperature that is independent from the operating temperature of the remaining heating zones. Vehicle tire pieces are fed into the infeed end of the pyrolysis section by a rotatable feed cylinder that includes a screw-like flight extending from the inner wall of the feed cylinder. As the feed cylinder rotates, the flight directs the supply of vehicle tire pieces into the infeed end of the pyrolysis section. The pyrolysis section includes a rotary kiln that is divided into the plurality of heating zones. The vehicle tire pieces are fed through the plurality of heating zones in the rotary kiln from the infeed end of the rotary kiln to the discharge end of the rotary kiln, such that the tire pieces are pyrolyzed as they traverse the rotary kiln. A rotatable trommel is coupled to the discharge end of the rotary kiln to separate the pyrolyzed tire pieces into their constituent desirable materials.

Cold bonded ore–coal composite pellets for sponge ironmaking Part 1 Laboratory scale development

Abstract: There is a need for the development of efficient industrial processes to use iron ore fines of high grade. Attention is particularly drawn to rotary kiln sponge ironmaking technology using lump iron ore, where productivity is low and energy consumption high compared with gas based processes. Fundamental studies carried out elsewhere indicate that the reduction of lump iron is accelerated if a limited amount of carbonaceous material is incorporated in the agglomerate of iron ore fines. Based on these considerations, cold bonded ore–coal composite pellets have been developed for sponge ironmaking in a rotary kiln. These composite pellets were tested in the laboratory and found to reduce very quickly, compared with lump iron ore. Composite pellets were also tested in an 8 t/day rotary kiln sponge iron plant giving enhanced productivity and lower coal consumption, and these results will be presented in Part 2 of this paper (next issue).

Method of producing cement clinker and electricity

Abstract: In a method of producing cement clinker and electricity, cement raw mix and hydrocarbon are fed in a circulating fluidized bed boiler (1). Therein cement raw mix is calcined and steam is produced. Gas and solids out of the fluidized bed enter a cyclone (8), the solids being separated therein and returned to the bed. Part of those solids are first cooled down in a solids heat exchanger (9) producting steam. Fly ash consisting predominantly of lime and gas escaping the cyclone are passed through a heat exchanger (28, 33) and a filter (37). Hot bed material is discharged from the circulating fluidized bed and is ground with additives, then blended with lime being separated in the filter (37), then supplied to a rotary kiln (16), wherein the solids are clinkered. The produced steam is fed to a steam turbine island (42).

Coal pyrolysis in a rotary kiln: Part II. Overall model of the furnace

Abstract: In order to simulate coal pyrolysis in a rotary kiln in the steady-state regime, a mathematical model has been developed which calculates the temperature profiles in the charge, the gas, and the furnace walls, together with the gas composition and the degree of removal of volatile species. The model takes into account the principal physicochemical and thermal phenomena involved, including the complex movements of the charge; the gas flow; heat transfer between the charge, the gas phase, and the furnace walls; drying and pyrolysis of the coal; the cracking of tars; the combustion of volatile species; and the combustion and extinction of the coke. The data necessary for the model were obtained by specific experiments or from the literature. The model has been validated by comparing its predictions to measurements performed on an industrial rotary kiln. The model has been used to study the influence of operating parameters such as the furnace rotation speed, in order to optimize the process. It is shown how a modification to the extinction zone leads to an increase in coke yield of 0.75 pct.

Coal pyrolysis in a rotary kiln: Part I. Model of the pyrolysis of a single grain

Abstract: A mathematical model is presented which describes the pyrolysis of a single grain of coal and is designed to be incorporated into an overall model simulating the rotary kiln coal pyrolysis process. The grain model takes into account the principal physical phenomena occurring during the conversion of coal to coke, namely, heat transfer toward and within the grain, drying of the coal, and the evolution of volatile species. Particular care has been taken in the determination of the thermophysical and kinetic parameters necessary for the model. Thus, the drying kinetics for Lorraine coal were measured by thermogravimetry. The kinetics of pyrolysis were determined by both thermogravimetry and gasphase chromatography, in order to separately monitor the evolution of the nine gaseous species considered. The true specific heat and the thermal conductivity of the solid were also measured as a function of temperature. The numerical model, based on the finite-volume method, calculates the temperature, composition, and mass flow rates for the different gases evolved at each point in the grain at any instant of time. The model was, finally, validated by comparing the calculated and measured values of the overall conversion of the pyrolysis reaction and the temperature at the center of the grain.

Characterization of total organic carbon in solid residues provides insight into sludge incineration processes

Abstract: In this paper, an analytical method is presented to determine the concentrations of elemental carbon (EC) and organic carbon (OC) in incinerator residues. This method is applied to sewage sludge incinerators with different combustion technologies. The results show that the OC concentrations are below the detection limit of 0.01 g/kg of dry matter (DM) and that the EC concentrations are lower than 0.3 g/kg of DM in the solid residues of the investigated stationary fluidized-bed furnace and of the multiple-hearth furnace. The OC concentrations in the investigated rotary kiln are lower than 2.5 g/kg of DM, and the EC concentrations are between 20 and 35 g/kg of DM in the rotary kiln bottom ash. Information on processes occurring in the rotary kiln are obtained by determining the EC and OC concentrations in different particle size classes of the bottom ash as well as by sampling the bottom ash during the turn-off of the rotary kiln and determining the EC and OC concentrations in these samples. By combining the results with the process parameters, it is concluded that the OC/EC ratio is a viable indicator for the temperatures within the furnace bed, while the EC concentration indicates the oxygen supply intomore » the furnace bed.« less

Cleaning apparatus for contaminated soil including volatile organic compound

Abstract: PROBLEM TO BE SOLVED: To provide a cleaning apparatus for contaminated soil including volatile organic compound which allows the treated soil which is easily handled by subjecting the contaminated soil to cleaning treatment SOLUTION: A rotary kiln 1 for heating which heats the contaminated soil is disposed and an exhaust duct 8 of the rotary kiln 1 for heating is connected with a deodorizing furnace 11 provided with a burner 12 via a dust collector 9 Further, a rotary kiln 21 for cooling which cools the heated soil discharged from the rotary kiln 1 for heating is disposed, the rotary kiln 21 for cooling is equipped with a water injection nozzle 26 which injects water and a dust collector 29 is disposed on the downstream side of the exhaust duct 27 of the rotary kiln 21 for cooling The soil which is subjected to heating treatment in the rotary kiln 1 for heating is supplied to the rotary kiln 21 for cooling and the heated soil is cooled by injecting water from the water injection nozzle 26 and is made to be a state which is easily handled

Process and installation for combined treatment of shredder scrap and sludges

Abstract: The process for the treatment of crushing residues and sludge, heats the residue to give a solid matter rich in cleaned carbon and a gas byproduct rich in hydrocarbons. The solid material is processed mechanically to extract metal matter and treated carbon, followed by heating which also disposes of the combustible gases. The final heat stage gives decontaminated cinders and an exhaust vapor. To process crushing residue and sludge, the material has a light granular fraction, with particles ≥ 13 mm. The sludges are from cleaning stations or from dredging. The heating stage is at a temperature to give a mass ratio of 1:1 between the cleaned carbon and the developed gas. The calorific value of the residues is 3500-4500 kcal/kg and of the sludge is 650-750 kcal/kg. The heat level is set to produce a gas with a calorific value of 6500-7500 kcal/kg and a cleaned carbon with a calorific value of 1000-2000 kcal/kg. The final heat stage has successive steps through at least one cyclone, at least one combustion chamber, at least one boiler, past an injection of lime, active carbon and at least one rod filter. The exhaust vapors from the heating stages are controlled to determine the concentrations of heavy metals, dioxins and furanes. The co-combustion of the carbon and the produced gas gives a mass ratio of 1:1 at a temperature of 1400 degrees C. The final temperature achieved is set according to the mass ratio of the sludge and the cleaned carbon, at a level of 1050-1250 degrees C or 1100 degrees C to give a mass ratio between the sludge and cleaned carbon of 5. An Independent claim is included for an assembly to process crushing residues and dredging sludge with a heating stage (13) to convert the light residues into a solid material rich in cleaned carbon, and a gas rich in hydrocarbons in a mass ratio of 1:1. A mechanical separation stage (16-19) separates a major fraction of metals present. A feed station (22-28) takes in dredging sludge, to be passed to a mixing station (20) to be mixed with the mechanically-cleaned solid material. The mixture is injected (32) into a high temperature rotary kiln (31), together with combustion air and a combustible gas to the burner. A twin-wall conveyor (33) takes the decontaminated cinders from the kiln, with indirect water cooling. The exhaust fumes from the kiln are scrubbed (36-40,47) before release (46,41) into the atmosphere, to retain the carried dust particles (42,43) and the calorific value of the exhaust fumes is exploited (44,45). Preferred Features: The metal separator has a 3 mm screen (16), followed by two crusher cylinders in a cascade configuration, preferably open at 500 microns m (17) and 250 microns m (18), for the crushed material to drop by gravity to a further 500 microns m screen (19). The feed station for the sludge has at least one hopper with an array of plungers. The cleaning system for the exhaust fumes has at least one cyclone (36) followed by a boiler (37) with an ante-chamber for post-combustion. The boiler is followed by a reactor to neutralize the fumes (38) and retain heavy metals by the injection of lime wash (40) and preferably active carbon (39). The output from the reactor is passed to a rod filter (47). The boiler is a vapor generator leading to a turbine (44), coupled to an alternator to generate electricity. The retained dust is carried by a mass conveyor with insulation (42) at the cyclone, boiler and filter, leading to a big bag disposal point (43).

Manufacturing method of carbide

Abstract: PROBLEM TO BE SOLVED: To provide a manufacturing method of carbide which is possible to manufacturing the carbide having non malodor and high adsorptivity. SOLUTION: In an indirect heating type rotary kiln performing to introduce a raw material from a front zone of a kiln body 1 and draw a product from a rear zone, the rotary kiln is used by maintaining a slightly positive pressure to prevent the contamination with air, feeding a purging gas retaining reducing atmosphere from a purging gas feed opening 8 in the rear zone of the kiln body 1 to be flown to the front zone, and discharging the resulting gas from a gas discharge opening 9 in the front zone. A large quantity of a harmful gas caused at the early stage of carbonization can be quickly removed out of the kiln, and an adhesive harmful gas to the carbide is removed by contacting the carbide with the fresh purging gas fed from the rear zone, therefore high quality carbide is obtained. COPYRIGHT: (C)2002,JPO

Process for the production of cement clinker in the rotary kiln intake chamber

Abstract: In cement clinker production installations, especially with short rotary tubular kiln, in order to find a way in which the thermally highly stressed rotary kiln intake chamber can be protected from overstress and therewith the entire production installation can be reliably operated it is proposed, according to the invention, to introduce directly into the rotary kiln intake chamber, a finely granular non-preheated substance usable in the cement clinker production process, to suspend or disperse it there in the rotary kiln exhaust gas and thereby to continuously cool the kiln intake chamber, and to discharge the heated finely granular substance with the exhaust gas from the kiln intake chamber and to add it to the process raw meal or direct it elsewhere.

Process for calcining an ore-based material

Abstract: In this process the material is passed through a precalcination device equipped with at least one fuel injector at the outlet of which a fuel injection zone is formed, then the at least partially calcined material is passed into the rotary kiln which at its downstream end, is equipped with a primary combustion unit. At least one oxygen rich fluid with an oxygen concentration by volume higher than that of the products of combustion from the rotary kiln is injected near to the injection zone so that the oxygen rich fluid can supply from 1% to 40%, and preferably form 1 to 10% of the stoichiometric amount of oxygen needed for the combustion of the fuel injected by the injector.

Device for automatically and continuously measuring temp. in calcining rotary kiln

Abstract: The utility model relates to a device for automatically and continuously measuring the temperature of a calcination rotary kiln. One or more temperature sensors are installed on the kiln body, and the temperature signals are converted into digit signals by a digital coding circuit and an analogue-to-digital conversion circuit controlled by a microprocessor through a transmitting amplifying circuit in each emitter, and then the digit signals are emitted by a wireless emitting circuit. Each receiver is connected to a control microcomputer for data display and data storage through a digitized wireless temperature measurement signal receiving circuit, a digit signal demodulation circuit, a microprocessor circuit and a microcomputer network communication circuit. The utility model can obtain the continuous, accurate and real time measurement of the temperature distributed a kiln, and can increase the anti-jamming capability of a temperature measurement system.

Development of Dechlorination Process for PVC in Waste Plastics.

Abstract: To utilize waste polyvinyl chloride (PVC), the removal of chlorine in PVC has been studied by newly designed rotary kiln. Coarse coke was simultaneously supplied to prevent an agglomeration of PVC particle and sticking to an inner wall of kiln during PVC dechlorination reaction. The heat for dechlorination was supplied from the outer tube of the rotary kiln so as to minimize the amount of processed gas containing HCl. Basically, it was verified that this rotary kiln could be smoothly operated due to the presence of coke particle. It was observed that dechlorinated residue was a porous materials formed along with the removal of HCl and was coated with coke particle. Dechlorination efficiency of PVC increased with an increase in the processing temperature and retention time in kiln. Dechlorination reaction of soft PVC was a little different from that of rigid PVC because of containing plasticizer in soft PVC. It was considered that plasticizer in soft PVC was inhibited dechlorination reaction. From the above results, it was concluded that an optimum reaction conditions to give 95% of dechlorination efficiency were the processing temperature of 350°C, the retention time of over 15min and the PVC/Coke weight ratio of 1.0. Yield of the dechlorinated residue for the use of blast furnace was 40% for rigid PVC and 20 to 40% for soft PVC. It was estimated that the application of this process enable to utilize effectively industrial and municipal waste plastics containing PVC in the blast furnace.

An innovative process for direct reduction of cold-bound pellets from Iron concentrate with a coal-based rotary kiln

Abstract: Successfully developed an innovative process of direct reduction of cold-bound pellets from iron ore concentrate with a coal-based rotary kiln, in comparison with the traditional direct reduction of fired oxide pellets in coal-based rotary kilns, possesses such advantages as: shorter flowsheet, lower capital investment, greater economic profit, good quality of direct reduced iron. The key technologies, such as the composite binder and corresponding feasible techniques were employed in practice. A mill utilizing this process and with an annual capacity of 50 thousand ton DRI has been put into operation.

Method and facilities for metal smelting

Abstract: A method for metal smelting, which comprises a step of pre-reducing a mixed raw material provided by mixing in advance or mixing-granulating or mixing-molding at least a metal oxide and/or hydroxide and a carbonaceous material in a pre-reduction furnace such as a rotary hearth type or rotary kiln type furnace so that 5 to 55 % of the metal oxide and/or hydroxide is reduced to metallic state on average, and a step of charging the pre-reduced mixed material to a smelting furnace for use in metal smelting and melting and finally reducing the material in the smelting furnace by using a carbonaceous material as a reducing agent and utilizing the combustion heat of the carbonaceous material and that of the carbon monoxide generated in the furnace as main heat sources. The method allows the production of a molten metal with good energy balance and high efficiency in production, and thus enables the production of a molten metal by the smelting reduction of a metal oxide and/or hydroxide such as an iron ore with high productivity and at a low cost.

Desilication from diasporic bauxite by roasting-alkali leaching process (I)

Abstract: Using the ore from Sanxi province, the roasting process of the desilication from the diasporic bauxite was studied. It was shown that using rotary kiln as the roasting apparatus is practicable, and the optimum roasting parameters are: grain size 0～20 mm, roasting temperature 1 050～1 100 ℃, roasting time 15～20 min. The alkali leaching results, rate of desilication 55.61% and ratio between aluminium and silicon of the concentrate 9.92, were obtained. By means of XRD analysis, the following conclusions were reached: only Si, existed in kaolinite, could be changed into noncrystalline silica; during the leaching, this kind of silica is dissolved by NaOH solution, but α silica does not dissolve, so it is not contributive to desilication. The digestion of the concentrate by Bayer process also showed that the digestion ratio of Al 2O 3 of the concentrate is higher than that of raw ore.

Physical characteristics of rotary kiln expanded slate lightweight aggregate

Abstract: This paper discusses the unique physical characteristics of rotary kiln expanded slate lightweight aggregate for producing high performance and high strength lightweight concrete. The compressive strength, elastic modulus, splitting tensile strength, specific creep, and other properties of lightweight concrete are significantly affected by the structural properties of the lightweight aggregate used. Concrete production, transportation, pumping and placing are also affected. Raw materials and rotary kiln processing is discussed. Data from academic and laboratory studies is presented as well as data from actual projects such as the Raftsundet Bridge in Norway and the Hibernia Offshore Oil Platform Gravity Base Structure. (A) For the covering abstract see ITRD E123363.

Fermenting processing device, device for manufacturing raw fuel for manufacturing cement, and cement plant

Abstract: PROBLEM TO BE SOLVED: To provide a fermenting processing device which can provide a way to effectively utilize idle devices installed in a cement plant such as a rotary kiln for treating waste and to provide a device for manufacturing raw fuel for manufacturing cement using the same and the cement plant which is provided with them and gives attention to resources and environment. SOLUTION: A cement kiln or a rotary drier for manufacturing the cement, from which lining bricks are removed, is used as the fermenting processing device 202 for composting the waste. COPYRIGHT: (C)2001,JPO

Fermenting processing method and method for manufacturing cement

Abstract: PROBLEM TO BE SOLVED: To provide a fermenting processing method and a method for manufacturing cement by which a way to effectively utilize devices installed in a cement plant such as a rotary kiln for treating waste can be provided. SOLUTION: In the fermenting processing method of the waste using the rotary kiln or a rotary drier, the waste to be subjected to fermentation treatment includes municipal waste accommodated in refuse bags and the waste is charged as it is in the cement kiln or the rotary drier for manufacturing the cement without breaking the bags and is subjected to fermentation treatment. COPYRIGHT: (C)2001,JPO

Method for manufacturing activated carbon from waste and manufacturing device

Abstract: PROBLEM TO BE SOLVED: To provide a method for manufacturing activated carbon by which the heat supplied from the outside is minimized at the time of continuously carbonizing and activating waste as the raw material to manufacture activated charcoal, and the waste is efficiently carbonized in the carbonization stage. SOLUTION: Scrap wood 25 is continuously charged into a rotary kiln 11. A combustion gas formed by burning an activation-furnace gas is introduced into an aerated partial combustion and carbonization part 12. The scrap wood 25 is aerated, partially burned by the combustion gas, carbonized, passed through a retention part 13 to promote the carbonization of the scrap wood 25 and then sent to a secondary combustor 3 form an exhaust port 21. The obtained primary charcoal is sent to an activation furnace 2. LPG is introduced into a combustor 6, burned and then supplied to the activation furnace 2 along with steam and air to activate the primary carbon sent from a carbonization furnace 1. The activation-furnace gas is sent to a combustor 8, then cooled by a cooler 9 to such a temperature as to be supplied to the carbonization furnace 1 and introduced into the kiln 11.

External heating rotary kiln

Abstract: PROBLEM TO BE SOLVED: To obtain an external heating rotary kiln installed such that a rotary retort penetrates a heating chamber substantially horizontally in which a matter to be heated can be peeled off from the inner surface of a retort immediately upon adhesion thereto by containing a heat resistant rod-like material movably in the retort. SOLUTION: A furnace body 1 is internally partitioned into an upper heating chamber 4 and a lower flue 6 by means of a furnace bed 2. A retort 8 is disposed in the heating chamber 4 while penetrating it and rings 9 secured to the projecting end on the opposite sides are supported by a pair of rollers so that the retort 8 can be rotary driven. Six spaces are defined on the inner circumference of the retort 8 by a center large diameter ring 14 in the longitudinal direction, by a small diameter ring 15 in the radial direction, and by a stirring plate 11 in the circumferential direction and a rod-like material 17 made of a heat resistant material is contained movably in each space. According to the structure, a matter to be heated adhering to the inner surface of the retort can be peeled off and since the matter can flow smoothly, it can be heat treated uniformly and efficiently.

Process and plant for producing cement

Abstract: PROBLEM TO BE SOLVED: To provide a cement production process which enables reduction of the sulfur oxide content in a flue gas of a cement firing equipment without using any expensive flue gas treatment equipment utilizing reactants such as alkali and gypsum, or an adsorbent. SOLUTION: This production process involves preheating and calcining a cement raw material with a preheater cyclone group having at least one cyclone and a calcination furnace respectively and firing the preheated and calcined raw material with a rotary kiln wherein the raw material is divided into two portions and one of the portions is directly supplied to at least one equipment selected from the group consisting of the calcination furnace, the lowest stage cyclone and the preceding stage cyclone among the preheater cyclone group.

Combustion method of flammable waste, and its device

Abstract: PROBLEM TO BE SOLVED: To provide a burning method of a flammable waste in which a cement clinker can be economically and stably manufactured while burning the flammable waste such as waste plastic, and its device. SOLUTION: A flammable waste of 60 mg or under in average weight is blown into a rotary kiln from a flammable waste flow passage 7 of a main fuel burner 6, and the primary air from a combustion primary air flow passage 8. The pulverized coal forming a main fuel carried on the conveying air from a main fuel flow passage 9, and the primary air from a second combustion primary air flow passage 10 are blown into the rotary kiln, respectively to implement the combustion thereof.

Continuous carbonization device for solid waste

Abstract: PROBLEM TO BE SOLVED: To provide a continuous carbonization device for solid wastes wherein the contact between air or combustion gas and a raw material is improved, the carbonization efficiency is improved, the device is made compact, and partial combustion and carbonization are stably conducted SOLUTION: The entire rotary kiln 1 except for the parts near both ends is a ventilation part 2 wherein numerous vent holes are formed A tubular outer body 8 is established at the outer periphery of the ventilation part 2 of the rotary kiln 1 while leaving a small gap On the lower surface of the outer body 8, an air-supplying wind box 9 for sending air or the combustion gas into the rotary kiln 1 is established On the upper surface of the outer body 8, an exhaust wind box 10 for exhausting carbonization gas, etc, is established An air-supplying aperture 11 and an exhaust aperture 12 are established on the air-supplying wind box 9 and the exhaust wind box 10, respectively A hot wind is introduced into the rotary kiln 1 through the ventilation part 2 via the air-supplying wind box 9 from the air-supplying aperture 11, and the introduction of the solid waste 22 is initiated The solid waste 22 is efficiently brought into contact with the air sent from the ventilation part 2 to promote its combustion and carbonization COPYRIGHT: (C)2001,JPO

Firing/treatment process of gypsum plaster board waste material

Abstract: PROBLEM TO BE SOLVED: To provide a firing/treatment process of a gypsum plaster board waste material by which anhydrous gypsum can be recovered from such a waste material without decomposing gypsum. SOLUTION: This process comprises steps of separating a gypsum plaster board waste material into a gypsum part and a paper part, firing the gypsum part at 600-900°C in a rotary kiln for forming cement clinker to recover gypsum as anhydrous gypsum, and supplying the paper part to a suspension preheater or rotary kiln used for forming cement clinker by firing. COPYRIGHT: (C)2002,JPO

Method and apparatus for burning flammable waste in burning step of cement clinker

Abstract: PROBLEM TO BE SOLVED: To provide a method and apparatus for burning a flammable waste in a burning step of a cement clinker, hardly providing a bad effect to the quality of the clinker, suppressing the generation of coating and enabling the stable kiln operation during a long period even in the case of using the flammable waste having ununiform combustion characteristics with large fluctuation in total in the actual operation of a rotary kiln with a new suspension preheater because various kinds and small quantity of the wastes are used and the combustion characteristics are different in each kind. SOLUTION: A feeding amount of a flammable waste is increased and decreased according to the measured values of a gas temperature at the gas outlet of cyclones 3a to 3d connected to the upper part of a calciner 2, and the gas temperature at the end 1a of a rotary kiln furnace 1 connected to the lower part of the calciner 2 when the flammable waste is fed to the calciner 2 of the rotary kiln 1 with a new suspension preheater.