Showing papers on "Rotary kiln published in 1978"

Heat transfer in a direct-fired rotary kiln: I. Pilot plant and experimentation

Abstract: The characterization of heat flow processes in direct-fired rotary kilns requires detailed measurements of gas, solids and wall temperatures This paper describes the construction, instrumentation and operation of a 55 m long x 0406 m inside diam kiln designed for such measurements The heating of inert sand was chosen for experimental study Methods of calculating heat flows among solids, wall and gas from the measured axial and radial temperatures are presented and the heat balance calculations and other necessary checks on the validity of the data are given The effects of the kiln operating variables on heat flow rates, and the implications of the results for modelling and scale-up to large kilns are discussed in Part II

Seal assembly and method for providing a seal in a rotary kiln

Abstract: A seal assembly and method for providing a contaminant-free, fluid-tight seal in a rotary kiln or similar rotating apparatus. A seal is provided between the rotating surfaces and the stationary surfaces of the kiln by providing an annular seal chamber defined by a rotating, outwardly-facing, U-shaped annular rim integral with the rotating surfaces of the rotary kiln and a stationary bellows chamber assembly integral with the stationary surfaces of the rotary kiln. An effective seal is maintained between the bellows chamber assembly and the annular rim by injecting a pressurized fluid into the bellows chamber so as to sufficiently bias its surfaces outwardly against the surfaces of the annular rim. The annular seal chamber is separated from the kiln chamber and its fluids and contaminants by an annular isolating chamber. The bellows chamber assembly prevents fluid communication between the seal chamber and the isolating chamber. The isolating chamber may communicate with the fluids of the kiln chamber via a one-way flap valve, and fluid is injected into the isolating chamber at a pressure sufficient to cause the injected fluid to flow from the isolating chamber, through the one-way valve and into the kiln chamber so as to prevent the flow of kiln fluids and contaminants into the isolating chamber.

Mixer block for use in rotary drums

Abstract: A mixer block used in rotary drums to improve the efficiency of mixing, drying, cooling, heating, or calcining of solid materials such as gravel, stone, fluxes and the like to produce a more uniform product with minimal production of fines and dust is described. The mixer block is especially useful when used as part of the refractory lining in a rotary kiln to calcine fluxstone such as limestone, dolomite, dolomitic limestone, magnesite and the like.

Process of calcining limestone in a rotary kiln

Abstract: A process for the calcining of limestone or hydrated lime by thermal treatment thereof with hot gases in a rotary kiln through which the kiln atmosphere and the charge are countercurrently passed, which kiln is fed with solid carbonaceous fuel, is described. The invention resides in introducing an oxygen-containing gas into a horizontal region across the rotary kiln defined by a point along the length of the kiln where ignitable particles of said solid fuel first appear and a second point along the length of said rotary kiln which is spaced from the charging end of said kiln not more than 50% of the length thereof. The oxygen-containing gases are injected through nozzle blocks in said rotary kiln, and oxygen-containing gas is introduced into the free space of said kiln.

Pyro-processing rotary kiln mixing rod

Abstract: A freely rotating rod or rods to be used in a high temperature rotary kiln, especially a cement kiln, to provide a combination of mixing and heat transfer is disclosed. The heat stable construction material and design of the rod permit heat in the kiln to be transferred more readily to the core of a feed material in a pyro-processing process, resulting in a more homogeneous end product. The rod has a unique and critical tapered structure of gradually enlarging transverse cross section. The rod, because of its tapered design, may be placed in the kiln oriented with the smaller cross section lying uphill to offset its tendency to travel downhill with the moving feed. The rod then remains generally stationary in its section of the kiln. Alternately, the rod may be sized and oriented so that it will travel through the kiln with the feed if such is desired. In the latter example, the degree of taper determines the speed of travel. Finally, the rod may be sized and oriented to travel uphill against the flow of material.

Apparatus for producing petroleum coke calcinate

Abstract: Green petroleum coke is indirectly dried, than calcined in a cylindrical rotary kiln and indirectly cooled utilizing a one-way gas flow in the system. Most of the dust in the vapor from the drying step is directly burned in a steam boiler whose off-gases are used to heat the dryer. Any residual dust in the gas is collected in an electro-filter. This dust together with dust which settles out from the dryer and the kiln is collected and added in controlled amounts to the dried coke before calcining. Hydrocarbons expelled during calcining are partially burned off with a stream of secondary air introduced at the coke exit end of the kiln. Most of the remaining hydrocarbons are burned off before they leave the coke inlet end of the kiln. The calcined coke product contains 0.1% by weight of hydrocarbons. The final off-gas from the process has a residual dust content of less than 100 mg/nm3.

Top-shaped lime kiln

Abstract: In a top-shaped lime kiln which comprises a slowly rotatable platter-shaped kiln bed having a cylindrical calcined lime-cooling chamber extending downward for connection to the central opening of said kiln bed; an immovably hung round lid having a fuel combustion chamber extending upward for connection to the central opening of said lid; and raw limestone granules-feeding chutes 19 opened to an annular gap 12 formed between the peripheral walls of both bed and lid; an improvement wherein a hot-gas-circulating apparatus is fixed in the maturation zone of the cooling chamber, and automatically reciprocative pushing rods are inserted into the limestone granule layer formed on the rotary kiln bed through the peripheral wall of said bed or lid so as to let fall the calcined lime into the cooling chamber.

Apparatus for re-aiming a coal burner pipe in a rotary kiln

Abstract: Apparatus is disclosed in which a coal burner pipe may be re-aimed into a rotary kiln. The burner pipe extends through a suitable opening provided in the associated hood of the kiln, with the discharge end of the burner pipe being so disposed as to discharge parallel to or obtusely to the axis of the kiln. Exteriorly of the kiln the coal burner pipe is provided with rigid angular pipe sections which can be reoriented relative to each other for effecting the re-aiming of the coal burner pipe within the kiln.

Fluid storage and distribution arrangement mounted on rotary reactor

Abstract: An arrangement for storing and distributing a fluid on board a rotary reactor such as a rotary kiln. The application discloses a rotary reduction kiln for reducing a metallic oxide such as iron oxide to a lower state of oxidation. A liquid hydrocarbon is used as a reductant in the reduction process for the metallic oxide. The kiln includes a cylindrical chamber adapted to receive the charge of material which is being subjected to the reduction process. A plurality of rows of nozzles are mounted on and supported by the kiln in hydraulic communication with the interior of the reduction chamber. Flow of hydrocarbon liquid to each row of nozzles is controlled by a corresponding flow control valve in accordance with the position of the corresponding row of nozzles relative to the charge of material in the kiln. A plurality of hydro-pneumatic accumulators having the hydraulic sections thereof connected to a common manifold are mounted on and rotatable with the kiln. Each accumulator includes a pneumatic section which is precharged to a predetermined pneumatic pressure. The common manifold of the hydraulic sections of the plurality of accumulators is hydraulically connected to the plurality of rows of nozzles through a pressure regulating device and through corresponding flow control valves whereby to provide a liquid supply at a controlled pressure and flow rate to the nozzles when the corresponding control valves are in "On" position.

Internal suspension preheater for long rotary kilns

Abstract: A long rotary kiln which slopes and wherein the particulate material travels downwardly from the inlet toward the outlet end and counter flowing gas travels upwardly therethrough, is provided with a preheater between the inlet end and the main operational zone. The preheater provides lifting devices at its end farthest from the inlet to deposit the particulate material in the gas stream, and an impingement separator zone at its end nearest the inlet to cause the particulate material to lose its momentum and fall from the gas.

Processes and apparatus for the heat treatment of fine-grained material

Abstract: Processes and apparatus for the heat treatment of fine-grained material, particularly for the production of cement, wherein the material is preheated in a preheater, further heated in a precalcination zone using additional fuel, calcined to completion in a rotary kiln, and cooled in a cooler, the preheated material being introduced into a cooling air stream run off from the cooler and the resulting mixture of gas and solids being introduced from the side into a gas pipe which connects the rotary kiln to the preheater and through which the kiln exhaust gases flow in the upward direction.

Process of calcining limestone or hydrated lime in a rotary kiln

Abstract: A process for the calcining of limestone or hydrated lime by thermal treatment thereof with hot gases in an oxidizing atmosphere in a rotary kiln through which the kiln atmosphere and the charge are countercurrently passed, which kiln is fed with fuel from shell burners, is described. The invention resides in the use of different fuels which release different quantities of SO 2 and SO 3 per unit of calorific heat. The fuel which releases the larger quantity of SO 2 or SO 3 per unit value of calorific heat is supplied to the upper portion of the rotary kiln, and the fuel which releases the smaller quantity of SO 2 and SO 3 per unit of calorific heat is supplied to the lower portion of the rotary kiln.

Method and apparatus for melting matrix materials

Abstract: A method and apparatus for economically melting matrix materials, said apparatus comprising a drier, a vertical furnace including a unique arrangement of refractory bars and a rotary kiln and the method including passing the solid matrix material first through a dryer which is heated by the waste gas of a vertical furnace, then to the top of the vertical furnace where it is melted by direct flame contact and thereafter cascading the melted material downwardly through said arrangement of refractory bars as the exhaust from a rotary kiln is blown upwardly through the vertical furnace with the melted material finally flowing from the bottom of the furnace into a rotary kiln where it is further heated and mixed prior to discharge.

Oxide film forming method for granular silicon for flux

Abstract: PURPOSE:To manufacture the product of uniform particle size being uniformly coated with the oxide film at a high productivity, by stirring and heating the kneaded material consisting of granular silicon as the base material and the peroxide solution, and after that, by further heating to higher temperatures. CONSTITUTION:The granular metallic silicon or silicon alloy and the peroxide solution at a specified proportion are charged into the mixer and are thoroughly kneaded; hereby, the peroxide solution is uniformly applied to the surface of the granular silicon. This granular material is discharged from the mixer, and is stored in the hopper, and then, is supplied from this hopper to the external combustion type rotary drier continuously. Within the rotary drier, the granular material is heated to about 400 deg.C while being stirred, and is mutually unbound from other pieces; as a result, the deposit of peroxide is formed on the surface of granular material. This granular material is continuously discharged from the drier and is stored in the hopper; from this hopper, the granular material is continuously charged into the rotary kiln. The granular material is heated to about 800 deg.C in the rotary kiln, and is taken out as the product, being followed by the cooling.

Scrapinggoff device for sticking matter on inner wall of rotary kiln

Abstract: PURPOSE:To carry out efficiently the operation for scraping off the sticking matter on the inner wall of the rotary kiln for pyrolysis of waste matter, by detecting the number of revolution of the basket-shaped body inserted into the main body of the above-mentioned kiln so as to move according to the rotation of the kiln, the position of the scraping-off plate, etc and by stopping intermittently the rotation of the basket-shaped body acccording to the detected values

Continuous production of hydrogen using metal scrap

Abstract: PURPOSE: To effectively utilize scrap metal as well as to continuously produce hydrogen in simple facilities by thermochemically reacting the metal with steam in a rotary kiln isolated from the air. CONSTITUTION: Scrap metal such as scrap iron is charged from charger 5 into horizontal rotary kiln 1 provided with steam seals 6, 6 at the front and rear ends, and steam is fed from blow hole 7 to be substituted for air in kiln 1. Kiln 1 is then preheated to above 300°C to start thermal decomposition of water with the metal. As the reaction starts, the temp. in kiln 1 rises, yet kiln 1 is optionally heated with furnace 8 to keep the temp. in kiln 1 at about 600W1000°C, thereby continuing the reaction. Hydrogen produced is taken out as product hydrogen H through pipes 10, 11 and gas cooler 12, and the scrap metal oxidized is put into water in vessel 13 and discharged from vessel 13 with scraper 14. Steam generated in vessel 13 is fed into kiln 1 from hole 7 through suction hole 15 and pipe 16. COPYRIGHT: (C)1980,JPO&Japio

Apparatus for fusing and combusting waste plastics

Abstract: PURPOSE:To combust waste plastics in continuous manner, by dividing a rotary kiln into a chamber in which plastics is fused and gasified and a chamber where the gasified plastics is combusted.

Method of firing a rotary kiln and apparatus therefor

Abstract: A method of firing a rotary kiln for the production of cement clinker is disclosed. The method includes the step of directing at least a major portion of the amount of fuel necessary for firing the kiln so as to be brought into direct contact with hot cement clinker in a precooling zone of the rotary kiln. There is further disclosed an apparatus for the production of cement clinker from cement raw meal. The apparatus comprises an inclined rotary kiln having a precooling zone in the lower end portion thereof in which cement raw meal collects and means for directing a jet of fuel into direct contact with hot cement clinker in the precooling zone of the material downstream end of the rotary kiln.

Discharging method for large lump in reducing rotary kiln

Abstract: PURPOSE:To make it possible to draw off large lumps in a rotary kiln while operating the rotary kiln without use of manpower or mechanical power, by controlling suitably the quantity of reducing agent and the rotating speed. CONSTITUTION:To a rotary kiln 1 which normally rotates at a rotating speed 0.6- 1.0rpm is fed green pellets 1b having been dried, preheated, and hardened in a preheater 2. Simultaneously, a reducing agent such as coal is charged from a feeder set to the lower part of an after-burner 3 at a rate about 0.45Cfix/Fe. The green pellets are reduced with reducing agent while being rolled in a mixed state to form CO, H2, which are burned with supplied air 4 and are directed to a discharging outlet 1a. When large lumps are formed in the kiln 1 during the operation, the reducing agent is remarkably increased temporarily to 0.60-1.00Cfix/Fe, and the rotating speed of the kiln 1 is notably decreased to 0.1-0.4rpm. As a result, large lumps in the kiln 1 are moved in the direction of the outlet 1a and are drawn off easily and suitably to the outside.

Rotary kiln furnace

Abstract: PURPOSE:To form pre-heating chambers between the kiln body and a outer cylinder secured to the periphery of the kiln body so that thermal efficiency can be improved.

Direct-reduction process carried out in a rotary kiln

Abstract: A process for directly reducing iron oxide-containing materials to provide sponge iron by heating said iron oxide-containing materials in a rotary kiln while employing a solid carbonaceous reducing agent having a high content of volatile combustible components, wherein oxygen-containing gases are injected into the rotary kiln at a controlled rate through shell pipes into the free kiln space and the charge is moved through the rotary kiln countercurrently to the flow of the kiln atmosphere, is described. The invention lies in injecting oxygen-containing gases at controlled rates through nozzle blocks into the charge disposed over said nozzle blocks and in injecting oxygen-containing gases at controlled rates through shell pipes into the free kiln space in that region of the heating-up zone defined by a point along the length of the heating-up zone where ignitable particles of the solid reducing agent first appear and a second point before the reducing zone.

Rotary kiln with a plurality of planetary cooling tubes

Abstract: A rotary kiln has at one end circumferentially spaced apart outlet openings into each of which extends a sleeve establishing communication between the interior of the kiln and a planetary cooling tube. Encircling the inner end of each sleeve is a refractory collar that is flush with the surface of the kiln's lining. Between each tube and the edge of the associated outlet is a thermally insulative packing.

Heat transfer by radiation in rotary kilns

Abstract: Equations were given for determining the effective emissivity in heat exchange by radiation between the gases, material, and lining of a rotary kiln, and the region of applicability of approximate equations was determined for the conditions of the thermal action of rotary kilns.

Infrared Spectroscopy in Cement Manufacture

Abstract: The application of infrared spectroscopy as a follow-up of the process of cement manufacture has been demonstrated with the help of infrared spectroscopic characterization of kiln feed and clinker samples obtained from a vertical shaft kiln plant as well as of ring samples collected from a rotary kiln. The possibility of employing the infrared spectroscopic technique for a broad quality control of ordinary portland cement and clinker has also been highlighted.