EP0248852A1 - Cylindrical rotary kiln - Google Patents

Cylindrical rotary kiln

Info

Publication number
EP0248852A1
EP0248852A1 EP87900044A EP87900044A EP0248852A1 EP 0248852 A1 EP0248852 A1 EP 0248852A1 EP 87900044 A EP87900044 A EP 87900044A EP 87900044 A EP87900044 A EP 87900044A EP 0248852 A1 EP0248852 A1 EP 0248852A1
Authority
EP
European Patent Office
Prior art keywords
screw
rotary tube
conveyor
rotary
stripping
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP87900044A
Other languages
German (de)
French (fr)
Inventor
Devender Dhingra
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Publication of EP0248852A1 publication Critical patent/EP0248852A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26—DRYING
    • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B11/00—Machines or apparatus for drying solid materials or objects with movement which is non-progressive
    • F26B11/02—Machines or apparatus for drying solid materials or objects with movement which is non-progressive in moving drums or other mainly-closed receptacles
    • F26B11/04—Machines or apparatus for drying solid materials or objects with movement which is non-progressive in moving drums or other mainly-closed receptacles rotating about a horizontal or slightly-inclined axis
    • F26B11/0463—Machines or apparatus for drying solid materials or objects with movement which is non-progressive in moving drums or other mainly-closed receptacles rotating about a horizontal or slightly-inclined axis having internal elements, e.g. which are being moved or rotated by means other than the rotating drum wall
    • F26B11/0477—Machines or apparatus for drying solid materials or objects with movement which is non-progressive in moving drums or other mainly-closed receptacles rotating about a horizontal or slightly-inclined axis having internal elements, e.g. which are being moved or rotated by means other than the rotating drum wall for mixing, stirring or conveying the materials to be dried, e.g. mounted to the wall, rotating with the drum
    • F26B11/0481—Machines or apparatus for drying solid materials or objects with movement which is non-progressive in moving drums or other mainly-closed receptacles rotating about a horizontal or slightly-inclined axis having internal elements, e.g. which are being moved or rotated by means other than the rotating drum wall for mixing, stirring or conveying the materials to be dried, e.g. mounted to the wall, rotating with the drum the elements having a screw- or auger-like shape, or form screw- or auger-like channels
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10B—DESTRUCTIVE DISTILLATION OF CARBONACEOUS MATERIALS FOR PRODUCTION OF GAS, COKE, TAR, OR SIMILAR MATERIALS
    • C10B47/00—Destructive distillation of solid carbonaceous materials with indirect heating, e.g. by external combustion
    • C10B47/28—Other processes
    • C10B47/30—Other processes in rotary ovens or retorts
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10B—DESTRUCTIVE DISTILLATION OF CARBONACEOUS MATERIALS FOR PRODUCTION OF GAS, COKE, TAR, OR SIMILAR MATERIALS
    • C10B47/00—Destructive distillation of solid carbonaceous materials with indirect heating, e.g. by external combustion
    • C10B47/28—Other processes
    • C10B47/32—Other processes in ovens with mechanical conveying means
    • C10B47/44—Other processes in ovens with mechanical conveying means with conveyor-screws
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10B—DESTRUCTIVE DISTILLATION OF CARBONACEOUS MATERIALS FOR PRODUCTION OF GAS, COKE, TAR, OR SIMILAR MATERIALS
    • C10B53/00—Destructive distillation, specially adapted for particular solid raw materials or solid raw materials in special form
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26—DRYING
    • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B11/00—Machines or apparatus for drying solid materials or objects with movement which is non-progressive
    • F26B11/02—Machines or apparatus for drying solid materials or objects with movement which is non-progressive in moving drums or other mainly-closed receptacles
    • F26B11/04—Machines or apparatus for drying solid materials or objects with movement which is non-progressive in moving drums or other mainly-closed receptacles rotating about a horizontal or slightly-inclined axis
    • F26B11/0463—Machines or apparatus for drying solid materials or objects with movement which is non-progressive in moving drums or other mainly-closed receptacles rotating about a horizontal or slightly-inclined axis having internal elements, e.g. which are being moved or rotated by means other than the rotating drum wall
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B7/00—Rotary-drum furnaces, i.e. horizontal or slightly inclined
    • F27B7/14—Rotary-drum furnaces, i.e. horizontal or slightly inclined with means for agitating or moving the charge
    • F27B7/18—Rotary-drum furnaces, i.e. horizontal or slightly inclined with means for agitating or moving the charge the means being movable within the drum

Definitions

  • the invention relates to a rotary kiln or drum oven with conveying devices arranged in the interior of the rotary tube or in the interior of the drum.
  • Rotary tube furnaces are used in particular in the cement industry and for metallurgical processes and enable the continuous production of the desired products by solid reactions in a targeted gas atmosphere, which is generally conducted in countercurrent to the reaction material to be treated.
  • the rotary tube is arranged inclined with respect to the horizontal, so that the reaction material is gradually conveyed to the lower outlet end of the rotary tube under the influence of gravity and the rotary movement of the rotary tube.
  • DE-OS 29 44 693 describes a garbage pyrolysis rotary kiln, which is provided in the interior of the rotary tube with reversible fittings which are firmly connected to the rotary tube, so that it is possible even with the rotary tube in a horizontal position to effect the desired conveyance of the reaction material through the rotary tube, since the helical fittings firmly connected to the inside of the rotary tube form a transport spiral.
  • changes in the conveying speed can only be achieved by corresponding changes in the rotational speed of the rotating tube, so that there is still room for improvement.
  • baking of materials cannot be avoided in the case of the helical internals fixedly connected to the rotary tube, so that problems also arise in this regard.
  • DE-OS 26 42 294 describes a rotating vessel furnace, i. H. a rotary kiln, which is also provided with a transport spiral inside, which is fixedly connected to the rotary tube. This results in disadvantages similar to those already mentioned above.
  • the subject of DE-OS 25 38 356 is a heat treatment device with a cylindrical chamber, i. H. a rotary kiln, on the inner surface of the rotary tube a screw for material conveyance is arranged.
  • This screw can be moved freely on the fastening device relative to the inner surface of the rotary tube in order to avoid damage to the screw or the chamber due to the existing temperature differences. But it is determined by the fastening devices so that it can only be moved together with the rotary tube.
  • the heat treatment device designed in this way thus also recognizes the disadvantages mentioned above.
  • DE-OS 30 25 716 also describes a rotary kiln in which the material is conveyed along a spiral path during the heat treatment.
  • This path is formed by a rotatable, helical reaction tube which is arranged in the actual furnace. In this case, it is therefore a rotary kiln with a helical rotary tube.
  • This device too, is unsatisfactory due to the difficulties in the reaction material possibly sticking to the inner wall of the helical reaction tube and the fact that here too the reaction material cannot be conveyed independently of the speed of the rotary tube.
  • DE-OS 33 05 249 describes a device for carrying out the pyrolysis of a mixture of waste and coal in the form of a fixed tunnel kiln, the bottom surfaces of which are formed from a plurality of conveyor conveyors lying next to one another, in which screw conveyors are stored, which are stored convey the material through the tunnel oven and mix at the same time.
  • This device has the disadvantage that it is structurally very complex and does not allow the advantages of controlling the temperature distribution and the gas atmosphere of a rotary kiln.
  • the object of the present invention is now to overcome the disadvantages of the prior art mentioned above and to improve a rotary tube or drum oven of the type specified at the outset in such a way that a targeted passage of the reaction material through the rotary tube, an exact setting of the residence time , Any control of the speed of the rotary tube and the delivery rate as well as the treatment of sticky, pasty and also crusting masses is possible.
  • the invention thus relates to a rotary kiln with conveyor devices arranged in the interior of the rotary tube, which is characterized in that a conveyor screw which can be driven independently of the rotary tube is provided as the conveyor device.
  • This screw conveyor is preferably combined with a stripping screw which engages with the screw conveyor and strips off the reaction substance adhering to it and is driven together with the screw conveyor.
  • the screw conveyor and stripping screw have identical dimensions with regard to the ratio of length to diameter and the pitch of the screw winding as well as the cross-sectional shape of the individual screw flights.
  • the stripping screw is advantageously designed in such a way that it rests on the shape of the screw conveyor in order to ensure that the reaction material possibly adhering to the screw conveyor is completely stripped off.
  • the outer sides of these screws facing away from the area of engagement between the screw conveyor and stripping screw each rest on the inner wall of the rotary tube, in order in this way to keep the inner wall free of any adhering reaction material and to significantly improve the mixing and conveying of the To cause reaction goods.
  • the scraper screw can be arranged anywhere in relation to the screw conveyor, although it is preferred to provide it vertically above the screw conveyor, since this results in constructive advantages in terms of driving the two screws and a further improvement in mixing and conveying of the reaction material is effected in that the material stripped by means of the stripping screw from the inner wall of the rotary tube or from the surface of the conveyor screw falls back onto the conveyor screw and is further circulated and conveyed through the rotary tube.
  • the rotary kiln according to the invention is also preferably provided with devices with which the rotary tube can be driven independently of the screw conveyor and the screw conveyor, the rotary speeds of the rotary tube on the one hand or the conveyor screw and the screw conveyor on the other hand, so that it can be controlled independently is possible according to the invention, a targeted movement of the reaction material through the rotary tube with a corresponding. ' To effect residence time in the rotary kiln.
  • the material throughput through the rotary tube furnace can vary in a much broader range than was previously possible.
  • it is possible to divide the two screws into areas with different pitches in order to specifically influence the dwell times of the reaction mixture so that when using heating zones of different temperatures arranged outside the rotary tube, this becomes possible. to subject the material to targeted temperature / time cycles.
  • the arrangement according to the invention of a screw conveyor which can be driven independently of the rotary tube also enables the treatment of sticky, pasty or crusty material which could not previously be treated in rotary tube ovens.
  • the arrangement of the conveyor screw within the rotary tube also enables a substantially higher degree of filling of the rotary tube furnace, which enables a higher throughput with a shorter rotary tube length or drum length.
  • the screw conveyor in the form of a double screw with a stripping screw that can be driven together, a targeted transport of the material through the rotary kiln is also possible in the case of sticky, pasty. or viscous masses possible.
  • the design of the surfaces of the screw conveyor and stripping screw can further improve the mixing of the material and prevent the material from sticking to the screw conveyor, which means that tighter process parameters can be maintained.
  • the screw conveyor and the stripping screw from a heat-resistant material which is inert to the reaction participants to be treated in the rotary tube furnace, for example from a ceramic material, a heat-resistant inert metal or a corresponding metal alloy or the like.
  • FIG. 1 shows a schematic longitudinal section through a preferred embodiment of the rotary kiln according to the invention.
  • FIG. 2 is a sectional view of the rotary kiln shown in FIG. 1 along the line A-A.
  • the rotary kiln shown in FIG. 1 comprises a continuous rotary tube 1 which is surrounded by furnace windings 23 which are arranged within the furnace shell 15.
  • the furnace windings 23 can extend uniformly over the inner wall of the furnace shell 15, but can also be constructed differently or separately in order to enable reaction zones with different temperature conditions in the rotary tube 1.
  • a screw conveyor 2 and a stripping screw 3 are provided, which mesh with one another in the engagement area 4. In this way it is achieved that the eventual Any reaction material adhering to the screw conveyor 2 is stripped off the stripping screw 3 and can fall down.
  • the conveyor screw 2 and the stripping screw 3 are geometrically of the same design so that they can - if only partially shown - mesh with one another over the entire length in the furnace area.
  • the rotary kiln according to the invention has a screw conveyor 2 for the specific conveyance of the reaction material, it is not necessary to arrange the rotary tube inclined relative to the horizontal, so that a favorable horizontal arrangement of the entire device is possible.
  • the stripping screw 3 is arranged vertically above the screw conveyor 2, which has the advantage that the stripped in the engagement area 4 by the screw conveyor Reaction material can fall vertically downwards and is conveyed and circulated.
  • the screw conveyor 2, on the one hand, and the stripping screw 3, on the other hand, rest with their outer sides 5, 6 facing away from the engagement region 4 on the inner wall 7 of the rotary tube 1, so that the material possibly adhering there is also stripped off and moved further through the rotary tube.
  • the rotary kiln is provided with devices 8, 9, 10, 11, 12, 13 and 14 for independently driving rotary kiln 1 on the one hand and conveyor screw 2 and stripping screw 3 on the other.
  • the conveyor screw 2 is driven, which is coupled via the gear 12 to the stripping screw 3, so that both screws are connected turn at the same speed.
  • the chain 10 is also guided over the sprocket 21, with which the feed screw (not shown in more detail) is driven, which ensures that the reaction material to be treated is metered from the feed hopper 19 into the rotary tube 1.
  • the conveyor screw 2 and the stripping screw 3 are supported at their ends outside the furnace region in the shaft bearings 18, while the rotary tube 1 is supported in the rotary tube bearings 13 and 14 and is driven with the aid of a drive device, not shown.
  • the screw conveyor 2 and the stripping screw are designed in such a way that worm shafts 16 and 17 are arranged on the worm shafts 16 and 17, which run around the shafts and which are advantageously rolled onto a correspondingly shaped strip material Be produced outside of the shaft surfaces.
  • the reaction material introduced into the rotary tube 1 from the feed hopper 19 via the feed screw 20 is guided through the rotary tube with the aid of the screw conveyor 2 and the rotary movement of the rotary tube 1, any reaction material adhering to the rotary tube 1 or the screw conveyor 2 being stripped off by the stripping screw 3 becomes.
  • a targeted and freely controllable conveying speed of the reaction material through the rotary tube to the application device 22 is made possible.
  • the atmosphere required for the reaction is generated in the interior of the rotary tube, for example by blowing in an inert gas or a reaction gas in counterflow to the direction in which the reaction mixture is conveyed through the rotary tube.
  • the rotary kiln With the design of the rotary kiln according to the invention, it becomes possible to generate higher temperatures in the rotary tube, the outer tube being able to be rotated more quickly in order to avoid excessive temperature differences and / or damage to the rotary tube. Furthermore, by arranging the screw conveyor in the rotary tube, larger diameters of the rotary tube 1 are possible, which enables a higher throughput with consistently good reaction conditions. Finally, it is also possible to move the reaction material backwards or in a mitage step through the rotary tube by switching the conveyor screw, wherein specific movement conditions of the reaction material and thus targeted reaction conditions can also be set by reversing the direction of rotation of the rotary tube.
  • the arrangement of the stripping screw meshing with the screw conveyor 2 prevents the material from sticking to the conveyor device and the inside of the rotary tube, which in turn enables targeted reaction conditions and thus more uniform products.
  • the arrangement of differently designed and separately regulated furnace windings 23 enables reaction zones of different temperatures to be formed, with the corresponding operation of the conveyor screw 2 or the stripping screw 3 allowing targeted dwell times in the reaction zones concerned are.
  • the rotary kiln according to the invention is particularly suitable for the thermal treatment of sludge-like or pasty waste materials, for example tank residues, by thermal decomposition of these materials with the exclusion of air at temperatures in the range between approximately 350 ° C. and 650 ° C. for the recovery of energy or valuable Raw materials and to minimize residues and pollutants.
  • An essential feature of the teaching according to the invention is that the inevitable hindrance to transport through the furnace with such substances is achieved by adhesive phases which form with the aid of the screw conveyor and by the self-cleaning effect of the twin screw via the positive contact between the screw conveyor and the stripping screw becomes.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Combustion & Propulsion (AREA)
  • Muffle Furnaces And Rotary Kilns (AREA)
  • Furnace Charging Or Discharging (AREA)

Abstract

Un four tubulaire tournant comprend à l'intérieur du cylindre tournant des dispositifs convoyeurs. Une vis sans fin (2) peut être entraînée indépendamment du cylindre tournant (1) et est en prise de préférence avec une vis râcleuse (3) susceptible d'être entraînée en même temps qu'elle.A rotating tube furnace includes conveyor devices inside the rotating cylinder. A worm (2) can be driven independently of the rotating cylinder (1) and is preferably engaged with a scraper screw (3) capable of being driven at the same time as it.

Description

Drehrohrofen Rotary kiln
B e s c h r e i b u n gDescription
Gegenstand der Erfindung ist ein Drehrohrofen oder Trommel- ofen mit im Inneren des Drehrohrs bzw. im Inneren der Trom¬ mel angeordneten Fördereinrichtungen.The invention relates to a rotary kiln or drum oven with conveying devices arranged in the interior of the rotary tube or in the interior of the drum.
Drehrohröfen werden insbesondere in der Zementindustrie und für metallurgische Verfahren angewandt und ermöglichen die kontinuierliche Herstellung der gewünschten Produkte durch Feststoffreaktionen in einer gezielten Gasatmosphäre, die in der Regel im Gegenstrom zu dem zu behandelnden Reak¬ tionsgut geführt wird. Normalerweise wird das Drehrohr ge- genüber der Horizontalen geneigt angeordnet, so daß das Re¬ aktionsgut unter der Einwirkung der Schwerkraft und der Drehbewegung des Drehrohrs nach und nach zum tieferliegen¬ den Austrittsende des Drehrohrs gefördert wird.Rotary tube furnaces are used in particular in the cement industry and for metallurgical processes and enable the continuous production of the desired products by solid reactions in a targeted gas atmosphere, which is generally conducted in countercurrent to the reaction material to be treated. Normally, the rotary tube is arranged inclined with respect to the horizontal, so that the reaction material is gradually conveyed to the lower outlet end of the rotary tube under the influence of gravity and the rotary movement of the rotary tube.
Da die gezielte Förderung des Reaktionsguts durch das Dreh¬ rohr bei Drehrohrδfen dieser Art nur in unzureichender Wei¬ se gesteuert werden kann, hat es nicht an Versuchen ge¬ fehlt, hier Abhilfe zu schaffen.Since the targeted delivery of the reaction material through the rotary tube in rotary tube ovens of this type can only be controlled in an inadequate manner, there has been no lack of attempts to remedy this.
So beschreibt die DE-OS 29 44 693 einen Müllpyrolyse-Dreh¬ rohrofen, der im Inneren des Drehrohrs mit wendeIfδrmigen Einbauten versehen ist, die fest mit dem Drehrohr verbunden sind, so daß es möglich wird, auch bei waagerechter Lage¬ rung des Drehrohrs die gewünschte Förderung des Reaktions- guts durch das Drehrohr zu bewirken, da die fest mit der Innenseite des Drehrohrs verbundenen wendeiförmigen Einbau¬ ten eine Transportspirale bilden. Wenngleich nach der Lehre dieses Standes der Technik auch ein Rückwärtstransport des Reaktionsguts möglich ist, lassen sich Änderungen der För- dergeschwindigkeit nur durch entsprechende Änderungen der Drehgeschwindigkeit des Drehrohrs erreichen, so daß inso¬ weit noch Verbesserungswünsche offen sind. Darüber hinaus ist bei den fest mit dem Drehrohr verbundenen wendeiförmi¬ gen Einbauten das Anbacken von Materialien nicht zu vermei¬ den, so daß sich diesbezüglich ebenfalls Probleme ergeben.Thus, DE-OS 29 44 693 describes a garbage pyrolysis rotary kiln, which is provided in the interior of the rotary tube with reversible fittings which are firmly connected to the rotary tube, so that it is possible even with the rotary tube in a horizontal position to effect the desired conveyance of the reaction material through the rotary tube, since the helical fittings firmly connected to the inside of the rotary tube form a transport spiral. Although it is also possible to transport the reaction material backwards according to the teaching of this prior art, changes in the conveying speed can only be achieved by corresponding changes in the rotational speed of the rotating tube, so that there is still room for improvement. Furthermore baking of materials cannot be avoided in the case of the helical internals fixedly connected to the rotary tube, so that problems also arise in this regard.
Die DE-OS 26 42 294 beschreibt einen rotierenden Gefäßofen, d. h. einen Drehrohrofen, der in seinem Inneren ebenfalls mit einer Transportspirale versehen ist, die fest mit dem Drehrohr verbunden ist. Hierbei ergeben sich ähnliche Nach¬ teile wie sie oben bereits angesprochen worden sind.DE-OS 26 42 294 describes a rotating vessel furnace, i. H. a rotary kiln, which is also provided with a transport spiral inside, which is fixedly connected to the rotary tube. This results in disadvantages similar to those already mentioned above.
Gegenstand der DE-OS 25 38 356 ist eine Wärmebehandlungs- vorrichtung mit einer zylinderförmigen Kammer, d. h. ein Drehrohrofen, an dessen Innenfläche des Drehrohrs eine Schraube zur Materialförderung angeordnet ist. Diese Schraube ist zwar an der Befestigungseinrichtung relativ zur Innenfläche des Drehrohrs frei beweglich, um Beschädi¬ gungen der Schraube oder der Kammer aufgrund der bestehen¬ den Temperaturunterschiede zu vermeiden. Sie wird aber durch die Befestigungseinrichtungen festgelegt, so daß auch sie sich nur gemeinsam mit dem Drehrohr bewegen läßt. Damit läßt auch die in dieser Weise ausgebildete Wärmebehand¬ lungsvorrichtung die oben angesprochenen Nachteile erken¬ nen.The subject of DE-OS 25 38 356 is a heat treatment device with a cylindrical chamber, i. H. a rotary kiln, on the inner surface of the rotary tube a screw for material conveyance is arranged. This screw can be moved freely on the fastening device relative to the inner surface of the rotary tube in order to avoid damage to the screw or the chamber due to the existing temperature differences. But it is determined by the fastening devices so that it can only be moved together with the rotary tube. The heat treatment device designed in this way thus also recognizes the disadvantages mentioned above.
Die DE-OS 30 25 716 beschreibt ebenfalls einen Drehrohr¬ ofen, in dem das Gut während der Wärmebehandlung entlang einer wendeIfδrmigen Bahn gefördert wird. Diese Bahn wird durch ein drehbares, wendeiförmiges Reaktionsrohr gebildet, welches in dem eigentlichen Ofen angeordnet ist. Es handelt sich in diesem Fall somit um einen Drehrohrofen mit wendel- fδrmigem Drehrohr. Auch diese Vorrichtung vermag aufgrund der Schwierigkeiten bei dem etwaigen Festbacken des Reak- tionsguts an der Innenwandung des wendeiförmigen Reaktions- rohrs und der Tatsache nicht zu befriedigen, daß auch hier keine von der Drehzahl des Drehrohrs unabhängige Förderung des Reaktionsguts möglich ist. Schließlich beschreibt die DE-OS 33 05 249 eine Vorrichtung zur Durchführung der Pyrolyse eines Gemisches aus Müll und Kohle in Form eines feststehenden Tunnelofens, dessen Bo¬ denflächen deckend aus mehreren nebeneinanderliegenden För- dertrδgen ausgebildet ist, in denen Schneckenförderer ver¬ lagert sind, die das Material durch den Tunnelofen fördern und gleichzeitig durchmischen. Diese Vorrichtung besitzt den Nachteil, daß sie konstruktiv sehr aufwendig ist und nicht die Vorteile der Steuerung der Temperaturverteilung und der Gasatmosphäre eines Drehrohrofens ermöglicht.DE-OS 30 25 716 also describes a rotary kiln in which the material is conveyed along a spiral path during the heat treatment. This path is formed by a rotatable, helical reaction tube which is arranged in the actual furnace. In this case, it is therefore a rotary kiln with a helical rotary tube. This device, too, is unsatisfactory due to the difficulties in the reaction material possibly sticking to the inner wall of the helical reaction tube and the fact that here too the reaction material cannot be conveyed independently of the speed of the rotary tube. Finally, DE-OS 33 05 249 describes a device for carrying out the pyrolysis of a mixture of waste and coal in the form of a fixed tunnel kiln, the bottom surfaces of which are formed from a plurality of conveyor conveyors lying next to one another, in which screw conveyors are stored, which are stored convey the material through the tunnel oven and mix at the same time. This device has the disadvantage that it is structurally very complex and does not allow the advantages of controlling the temperature distribution and the gas atmosphere of a rotary kiln.
Die Aufgabe der vorliegenden Erfindung besteht nun darin, die Nachteile des oben angesprochenen Standes der Technik zu überwinden und einen Drehrohrofen bzw. Trommelofen der eingangs angegebenen Gattung derart zu verbessern, daß ein gezieltes Durchschleusen des Reaktionsguts durch das Dreh¬ rohr, eine genaue Einstellung der Verweilzeit, eine belie¬ bige Steuerung der Drehzahl des Drehrohrs und der Förder¬ menge sowie die Behandlung klebriger, pastöser und auch verkrustender Massen möglich wird.The object of the present invention is now to overcome the disadvantages of the prior art mentioned above and to improve a rotary tube or drum oven of the type specified at the outset in such a way that a targeted passage of the reaction material through the rotary tube, an exact setting of the residence time , Any control of the speed of the rotary tube and the delivery rate as well as the treatment of sticky, pasty and also crusting masses is possible.
Diese Aufgabe wird nun gelöst durch die kennzeichnenden Merkmale des Drehrohrofens gemäß Hauptanspruch. Die Unter¬ ansprüche betreffen besonders bevorzugte Ausführungsformen dieses Erfindungsgegenstandes.This object is now achieved by the characterizing features of the rotary kiln according to the main claim. The subclaims relate to particularly preferred embodiments of this subject of the invention.
Die Erfindung betrifft somit einen Drehrohrofen mit im In¬ neren des Drehrohrs angeordneten Fördereinrichtungen, der dadurch gekennzeichnet ist, daß als Fördereinrichtung eine vom Drehrohr unabhängig antreibbare Förderschnecke vorgese¬ hen ist.The invention thus relates to a rotary kiln with conveyor devices arranged in the interior of the rotary tube, which is characterized in that a conveyor screw which can be driven independently of the rotary tube is provided as the conveyor device.
Vorzugsweise ist diese Förderschnecke mit einer Abstreif¬ schnecke kombiniert, die mit der Förderschnecke im Eingriff steht und das daran anhaftende Reaktionsgut abstreift und gemeinsam mit der Förderschnecke angetrieben wird. Für. diesen Fall ist es besonders bevorzugt, daß Förderschnecke und AbstreifSchnecke identische Abmessungen aufweisen im Hinblick auf das Verhältnis von Länge zu Durchmesser und die Steigung der Schneckenwindung sowie die Querschnitts¬ form der einzelnen Schneckengänge. Mit Vorteil wird die Ab- streifSchnecke in der Weise ausgebildet, daß sie an der Form der Förderschnecke anliegt, um in dieser Weise das vollständige Abstreifen des an der Förderschnecke eventuell anhaftenden Reaktionsguts sicherzustellen.This screw conveyor is preferably combined with a stripping screw which engages with the screw conveyor and strips off the reaction substance adhering to it and is driven together with the screw conveyor. For. In this case, it is particularly preferred that the screw conveyor and stripping screw have identical dimensions with regard to the ratio of length to diameter and the pitch of the screw winding as well as the cross-sectional shape of the individual screw flights. The stripping screw is advantageously designed in such a way that it rests on the shape of the screw conveyor in order to ensure that the reaction material possibly adhering to the screw conveyor is completely stripped off.
Erfindungsgemäß ist es weiterhin bevorzugt, daß die vom Eingriffsbereich zwischen Förderschnecke und Abstreif¬ schnecke abgewandten Außenseiten dieser Schnecken jeweils an der Innenwand des Drehrohrs anliegen, um in dieser Weise die Innenwand von eventuell anhaftendem Reaktionsgut frei- zuhalten und eine deutliche Verbesserung der Durchmischung und Förderung des Reaktionsguts zu bewirken. Dabei kann die Abstreifschnecke räumlich beliebig zu der Förderschnecke angeordnet werden, wenngleich es bevorzugt ist, sie senk¬ recht oberhalb der Förderschnecke vorzusehen, da sich hier- durch konstruktive Vorteile im Hinblick auf den Antrieb der beiden Schnecken ergeben und eine weitere Verbesserung der Durchmischung und Förderung des Reaktionsguts dadurch be¬ wirkt wird, daß das mittels der AbstreifSchnecke von der Innenwand des Drehrohrs bzw. von der Oberfläche der Fδrder- Schnecke abgestreifte Material wieder auf die Fδrderschnek- ke fällt und weiter umgewälzt und durch das Drehrohr geför¬ dert wird.According to the invention, it is further preferred that the outer sides of these screws facing away from the area of engagement between the screw conveyor and stripping screw each rest on the inner wall of the rotary tube, in order in this way to keep the inner wall free of any adhering reaction material and to significantly improve the mixing and conveying of the To cause reaction goods. The scraper screw can be arranged anywhere in relation to the screw conveyor, although it is preferred to provide it vertically above the screw conveyor, since this results in constructive advantages in terms of driving the two screws and a further improvement in mixing and conveying of the reaction material is effected in that the material stripped by means of the stripping screw from the inner wall of the rotary tube or from the surface of the conveyor screw falls back onto the conveyor screw and is further circulated and conveyed through the rotary tube.
Der erfindungsgemäße Drehrohrofen ist weiterhin vorzugswei- s mit Einrichtungen versehen, mit denen das Drehrohr unab¬ hängig von Förderschnecke und AbstreifSchnecke angetrieben werden kann, wobei die Drehgeschwindigkeiten von Drehrohr einerseits bzw. Förderschnecke und AbstreifSchnecke ande¬ rerseits unabhängig voneinander gesteuert werden können, so daß es erfindungsgemäß möglich wird, eine gezielte Bewegung des Reaktionsguts durch das Drehrohr mit entsprechender.' Verweilzeit in dem Drehrohrofen zu bewirken. Darüber hinaus läßt durch eine entsprechende Steuerung der Bewegungen von Drehrohr einerseits und Förderschnecke und Abstreifschnecke andererseits bzw. ihren Abmessungen der Materialdurchsatz durch den Drehrohrofen in einem wesentlich breiteren Be¬ reich variieren als bislang möglich. Darüber hinaus ist es möglich, die beiden Schnecken in Bereiche mit unterschied¬ lichen Steigungen aufzuteilen, um in dieser Weise die Ver¬ weilzeiten des Reaktionsguts gezielt zu beeinflussen, so daß es bei Anwendung von außerhalb des Drehrohrs angeord¬ neten Heizzonen unterschiedlicher Temperatur möglich wird, das Material gezielten Temperatur/Zeit-Zyklen zu unterwer¬ fen.The rotary kiln according to the invention is also preferably provided with devices with which the rotary tube can be driven independently of the screw conveyor and the screw conveyor, the rotary speeds of the rotary tube on the one hand or the conveyor screw and the screw conveyor on the other hand, so that it can be controlled independently is possible according to the invention, a targeted movement of the reaction material through the rotary tube with a corresponding. ' To effect residence time in the rotary kiln. In addition, by appropriately controlling the movements of the rotary tube on the one hand and the conveying screw and stripping screw on the other hand or their dimensions, the material throughput through the rotary tube furnace can vary in a much broader range than was previously possible. In addition, it is possible to divide the two screws into areas with different pitches in order to specifically influence the dwell times of the reaction mixture, so that when using heating zones of different temperatures arranged outside the rotary tube, this becomes possible. to subject the material to targeted temperature / time cycles.
Durch die erfindungsgemäße Heizung des Drehrohrs von außen und die unabhängig einstellbare Drehgeschwindigkeit von Drehrohr einerseits und Förderschnecke bzw. Abstreif- Schnecke andererseits gelingt es, die auf das Reaktionsgut einwirkenden Parameter gezielt zu steuern und damit Reak- tionen durchzuführen, die bislang in dieser Weise nicht oder nur schwer möglich waren. Insbesondere ermöglicht die erfindungsgemäße Anordnung einer vom Drehrohr unabhängig antreibbaren Förderschnecke auch die Behandlung von klebri¬ gem, pastösem oder verkrustendem Material, welches bislang in Drehrohröfen nicht behandelt werden konnte. Insbesondere trifft dies beispielsweise auf die Pyrolyse oder thermische Zersetzung von Kunststoffen zu, die in herkömmlichen Dreh¬ rohröfen wegen des Anklebens des Materials an der Ofenwan¬ dung nicht praktikabel ist. Durch die Anordnung der Fδrder- Schnecke innerhalb des Drehrohrs wird weiterhin ein wesent¬ lich höherer Füllgrad des Drehrohrofens möglich, was einen höheren Durchsatz bei kürzerer Drehrohrlänge oder Trommel¬ länge ermöglicht. Durch den Einsatz der Förderschnecke in Form einer DoppelSchnecke mit gemeinsam antreibbarer Ab- Streifschnecke wird ein gezielter Transport des Materials durch den Drehrohrofen auch im Fall von klebrigen, pastösen. oder zähflüssigen Massen möglich. Durch eine entsprechende Gestaltung der Oberflächen von Förderschnecke und Abstreif¬ schnecke kann eine weitere Verbesserung der Durchmischung des Materials erreicht und das Anhaften des Materials an der Förderschnecke verhindert werden, wodurch sich engere Verfahrensparameter einhalten lassen.Due to the inventive heating of the rotary tube from the outside and the independently adjustable rotational speed of the rotary tube on the one hand and the screw conveyor or stripping screw on the other hand, it is possible to control the parameters acting on the reaction material in a targeted manner and thus to carry out reactions which have not hitherto been possible in this way were difficult. In particular, the arrangement according to the invention of a screw conveyor which can be driven independently of the rotary tube also enables the treatment of sticky, pasty or crusty material which could not previously be treated in rotary tube ovens. In particular, this applies, for example, to the pyrolysis or thermal decomposition of plastics, which is not practical in conventional rotary tube furnaces due to the material adhering to the furnace wall. The arrangement of the conveyor screw within the rotary tube also enables a substantially higher degree of filling of the rotary tube furnace, which enables a higher throughput with a shorter rotary tube length or drum length. Through the use of the screw conveyor in the form of a double screw with a stripping screw that can be driven together, a targeted transport of the material through the rotary kiln is also possible in the case of sticky, pasty. or viscous masses possible. By an appropriate The design of the surfaces of the screw conveyor and stripping screw can further improve the mixing of the material and prevent the material from sticking to the screw conveyor, which means that tighter process parameters can be maintained.
Schließlich ist es bevorzugt, nicht nur das Drehrohr, son¬ dern auch die Förderschnecke und die Abstreifschnecke aus einem hitzebeständigen Material zu fertigen, welches ge- gegenüber den in dem Drehrohrofen zu behandelnden Reak¬ tionsteilnehmern inert ist, beispielsweise aus einem Kera¬ mikmaterial, einem hitzebeständigen inerten Metall oder ei¬ ner entsprechenden Metallegierung oder dergleichen.Finally, it is preferred not only to manufacture the rotary tube, but also the screw conveyor and the stripping screw, from a heat-resistant material which is inert to the reaction participants to be treated in the rotary tube furnace, for example from a ceramic material, a heat-resistant inert metal or a corresponding metal alloy or the like.
Die Erfindung sei im folgenden näher unter Bezugnahme auf die beigefügten Zeichnungen erläutert. In den Zeichnungen zeigen:The invention is explained in more detail below with reference to the accompanying drawings. The drawings show:
Fig. 1 eine schematisσhe Längsschnittdarstellung durch eine bevorzugte Ausführungsform des erfindungsge¬ mäßen Drehrohrofens und1 shows a schematic longitudinal section through a preferred embodiment of the rotary kiln according to the invention, and
Fig. 2 eine Schnittansicht des in der Fig. 1 dargestell¬ ten Drehrohrofens längs der Linie A-A.FIG. 2 is a sectional view of the rotary kiln shown in FIG. 1 along the line A-A.
Der in der Fig. 1 dargestellte Drehrohrofen umfaßt ein durchlaufendes Drehrohr 1, welches mit Ofenwicklungen 23 umgeben ist, die innerhalb des Ofenmahtels 15 angeordnet sind. Die Ofenwicklungen 23 können sich gleichmäßig über die Innenwand des Ofenmantels 15 erstrecken, können jedoch auch unterschiedlicherweise oder getrennt aufgebaut sein, um in dem Drehrohr 1 Reaktionszonen mit unterschiedlichen Temperaturbedingungen zu ermöglichen. Im Inneren des Dreh¬ rohrs 1 sind eine Förderschnecke 2 und eine Abstreif- Schnecke 3 vorgesehen, die im Eingriffsbereich 4 miteinan¬ der kämmen. In dieser Weise wird erreicht, daß das eventu- eil an der Förderschnecke 2 anhaftende Reaktionsgut von der AbstreifSchnecke 3 abgestreift wird und nach unten fallen kann. Wie in der Fig. 1 dargestellt ist, sind die Förder¬ schnecke 2 und die Abstreifschnecke 3 geometrisch gleichar- tig ausgebildet, so daß sie - wenn auch nur teilweise dar¬ gestellt - über die gesamte Länge im Ofenbereich miteinan¬ der kämmen können.The rotary kiln shown in FIG. 1 comprises a continuous rotary tube 1 which is surrounded by furnace windings 23 which are arranged within the furnace shell 15. The furnace windings 23 can extend uniformly over the inner wall of the furnace shell 15, but can also be constructed differently or separately in order to enable reaction zones with different temperature conditions in the rotary tube 1. In the interior of the rotary tube 1, a screw conveyor 2 and a stripping screw 3 are provided, which mesh with one another in the engagement area 4. In this way it is achieved that the eventual Any reaction material adhering to the screw conveyor 2 is stripped off the stripping screw 3 and can fall down. As shown in FIG. 1, the conveyor screw 2 and the stripping screw 3 are geometrically of the same design so that they can - if only partially shown - mesh with one another over the entire length in the furnace area.
Da der erfindungsgemäße Drehrohrofen eine zur gezielten Förderung des Reaktionsguts dienende Förderschnecke 2 auf¬ weist, ist es nicht notwendig, das Drehrohr geneigt gegen¬ über der Horizontalen anzuordnen, so daß eine günstige ho¬ rizontale Anordnung der gesamten Einrichtung möglich ist.Since the rotary kiln according to the invention has a screw conveyor 2 for the specific conveyance of the reaction material, it is not necessary to arrange the rotary tube inclined relative to the horizontal, so that a favorable horizontal arrangement of the entire device is possible.
Wie in der Fig. 1 dargestellt und aus der Fig. 2 noch deut¬ licher zu erkennen ist, ist die AbstreifSchnecke 3 senk¬ recht oberhalb der Förderschnecke 2 angeordnet, was den Vorteil mit sich bringt, daß das im Eingriffsbereich 4 von der Förderschnecke abgestreifte Reaktionsgut senkrecht nach unten fallen kann und weitergefördert und umgewälzt wird. Wie aus den Zeichnungen und insbesondere der Fig. 2 eben¬ falls zu erkennen ist, liegen die Förderschnecke 2 einer¬ seits bzw. die AbstreifSchnecke 3 andererseits mit ihren vom Eingriffsbereich 4 abgewandten Außenseiten 5, 6 an der Innenwand 7 des Drehrohrs 1 an, so daß das dort eventuell anhaftende Material ebenfalls abgestreift und weiter durch das Drehrohr bewegt wird.As shown in FIG. 1 and can be seen even more clearly from FIG. 2, the stripping screw 3 is arranged vertically above the screw conveyor 2, which has the advantage that the stripped in the engagement area 4 by the screw conveyor Reaction material can fall vertically downwards and is conveyed and circulated. As can also be seen from the drawings and in particular from FIG. 2, the screw conveyor 2, on the one hand, and the stripping screw 3, on the other hand, rest with their outer sides 5, 6 facing away from the engagement region 4 on the inner wall 7 of the rotary tube 1, so that the material possibly adhering there is also stripped off and moved further through the rotary tube.
Wie in der Fig. 1 weiterhin schematisch dargestellt, ist der Drehrohrofen mit Einrichtungen 8, 9, 10, 11, 12, 13 und 14 zum unabhängigen Antrieb von Drehrohr 1 einerseits sowie Förderschnecke 2 und AbstreifSchnecke 3 andererseits versehen. In dieser Weise wird mit Hilfe des Motors 8 über das Antriebskettenrad 9 und die Kette 10 die Förderschnecke 2 angetrieben, die über das Getriebe 12 mit der Abstreif¬ schnecke 3 gekoppelt ist, so daß sich beide Schnecken mit gleicher Geschwindigkeit drehen. Mit Vorteil ist die Kette 10 auch noch über das Kettenrad 21 geführt, mit der die nicht näher dargestellte Aufgabeschnecke angetrieben wird, die die Zudosierung des zu behandelnden Reaktionsguts aus dem Aufgabetrichter 19 in das Drehrohr 1 sicherstellt. Bei dem in der Fig. 1 dargestellten Aufbau sind die Förder¬ schnecke 2 und die AbstreifSchnecke 3 an ihren Enden außer¬ halb des Ofenbereichs in den Wellenlagern 18 gelagert, wäh¬ rend das Drehrohr 1 in den Drehrohrlagern 13 und 14 gela- gert ist und mit Hilfe einer nicht näher dargestellten An¬ triebsvorrichtung angetrieben wird.As further shown schematically in FIG. 1, the rotary kiln is provided with devices 8, 9, 10, 11, 12, 13 and 14 for independently driving rotary kiln 1 on the one hand and conveyor screw 2 and stripping screw 3 on the other. In this way, with the help of the motor 8 via the drive sprocket 9 and the chain 10, the conveyor screw 2 is driven, which is coupled via the gear 12 to the stripping screw 3, so that both screws are connected turn at the same speed. Advantageously, the chain 10 is also guided over the sprocket 21, with which the feed screw (not shown in more detail) is driven, which ensures that the reaction material to be treated is metered from the feed hopper 19 into the rotary tube 1. In the construction shown in FIG. 1, the conveyor screw 2 and the stripping screw 3 are supported at their ends outside the furnace region in the shaft bearings 18, while the rotary tube 1 is supported in the rotary tube bearings 13 and 14 and is driven with the aid of a drive device, not shown.
Wie in der Fig. 1 dargestellt ist, sind die Förderschnecke 2 und die AbstreifSchnecke in der Weise ausgebildet, daß auf den Schneckenwellen 16 bzw. 17 schneckenförmige, um die Wellen herumlaufende Schneckengänge angeordnet sind, welche mit Vorteil durch Aufwalzen eines entsprechend geformten Bandmaterials auf die Außenseite der Wellenoberflächen her¬ gestellt werden. Es ist jedoch auch möglich, die Schnecken durch entsprechende spanabhebende Bearbeitung eines Vollma¬ terials herzustellen.As shown in Fig. 1, the screw conveyor 2 and the stripping screw are designed in such a way that worm shafts 16 and 17 are arranged on the worm shafts 16 and 17, which run around the shafts and which are advantageously rolled onto a correspondingly shaped strip material Be produced outside of the shaft surfaces. However, it is also possible to produce the screws by machining a solid material accordingly.
Das von dem Aufgabetrichter 19 über die Aufgabeschnecke 20 in das Drehrohr 1 eingeführte Reaktionsgut wird mit Hilfe der Förderschnecke 2 und der Drehbewegung des Drehrohrs 1 durch das Drehrohr geführt, wobei eventuell an dem Drehrohr 1 bzw. der Förderschnecke 2 anhaftendes Reaktionsgut von der AbstreifSchnecke 3 abgestreift wird. In dieser Weise wird eine gezielte und beliebig regelbare Fördergeschwin- digkeit des Reaktionsguts durch das Drehrohr bis zur Auf- tragseinrichtung 22 ermöglicht. Bei der Reaktion des Mate¬ rials wird im Inneren des Drehrohrs die für die Reaktion erforderliche Atmosphäre erzeugt, beispielsweise durch Ein¬ blasen eines Inertgases oder eines Reaktionsgases im Gegen- ström zu der Förderrichtung des Reaktionsguts durch das Drehrohr. Mit Hilfe der erfindungsgemäßen Auslegung des Drehrohrofens wird es möglich, höhere Temperaturen in dem Drehrohr zu er¬ zeugen, wobei das Außenrohr schneller gedreht werden kann, um zu starke Temperaturunterschiede und/oder eine Beschädi- gung des Drehrohrs zu vermeiden. Weiterhin sind durch die Anordnung der Förderschnecke in dem Drehrohr größere Durch¬ messer des Drehrohrs 1 möglich, was einen höheren Durchsatz bei gleichbleibend guten Reaktionsbedingungen ermöglicht. Schließlich ist es auch möglich, durch Umschalten der För- derschnecke das Reaktionsgut rückwärts oder im Pilger¬ schritt durch das Drehrohr zu bewegen, wobei auch durch Umkehr der Drehrichtung des Drehrohrs gezielte Bewegungsbe¬ dingungen des Reaktionsguts und damit gezielte Reaktionsbe¬ dingungen eingestellt werden können. Dabei wird durch die Anordnung der mit der Förderschnecke 2 kämmenden Abstreif¬ schnecke ein Anhaften des Materials an der Fördereinrich¬ tung und der Drehrohrinnenseite vermieden, was wiederum ge¬ zielte Reaktionsbedingungen und damit einheitlichere Pro¬ dukte ermöglicht. Durch die Anordnung unterschiedlich aus- gebildeter und getrennt geregelter Ofenwicklungen 23 ist, wie bereits angesprochen wurde, die Ausbildung unterschied¬ lich temperierter Reaktionszonen möglich, wobei durch den entsprechenden Betrieb der Förderschnecke 2 bzw. der Ab¬ streifschnecke 3 gezielte Verweilzeiten in den betreffenden Reaktionszonen möglich sind.The reaction material introduced into the rotary tube 1 from the feed hopper 19 via the feed screw 20 is guided through the rotary tube with the aid of the screw conveyor 2 and the rotary movement of the rotary tube 1, any reaction material adhering to the rotary tube 1 or the screw conveyor 2 being stripped off by the stripping screw 3 becomes. In this way, a targeted and freely controllable conveying speed of the reaction material through the rotary tube to the application device 22 is made possible. When the material reacts, the atmosphere required for the reaction is generated in the interior of the rotary tube, for example by blowing in an inert gas or a reaction gas in counterflow to the direction in which the reaction mixture is conveyed through the rotary tube. With the design of the rotary kiln according to the invention, it becomes possible to generate higher temperatures in the rotary tube, the outer tube being able to be rotated more quickly in order to avoid excessive temperature differences and / or damage to the rotary tube. Furthermore, by arranging the screw conveyor in the rotary tube, larger diameters of the rotary tube 1 are possible, which enables a higher throughput with consistently good reaction conditions. Finally, it is also possible to move the reaction material backwards or in a pilgrimage step through the rotary tube by switching the conveyor screw, wherein specific movement conditions of the reaction material and thus targeted reaction conditions can also be set by reversing the direction of rotation of the rotary tube. The arrangement of the stripping screw meshing with the screw conveyor 2 prevents the material from sticking to the conveyor device and the inside of the rotary tube, which in turn enables targeted reaction conditions and thus more uniform products. As already mentioned, the arrangement of differently designed and separately regulated furnace windings 23 enables reaction zones of different temperatures to be formed, with the corresponding operation of the conveyor screw 2 or the stripping screw 3 allowing targeted dwell times in the reaction zones concerned are.
Wie oben bereits angesprochen, ist es möglich, die Förder¬ schnecke 2 bzw. Abstreifschnecke 3 in unterschiedlich aus¬ gebildete Teilabschnitte aufzuteilen, die verschiedene Steigungen aufweisen, um in dieser Weise die Verweilzeit des Materials in den unterschiedlich temperierten Reak¬ tionszonen gezielt zu variieren.As already mentioned above, it is possible to divide the conveyor screw 2 or stripping screw 3 into sections of different design, which have different pitches, in order in this way to specifically vary the residence time of the material in the reaction zones at different temperatures.
Schließlich wird es mit Hilfe des erfindungsgemäßen Dreh- rohrofens möglich, die Drehzahl des Drehrohrs 1 beliebig, beispielsweise innerhalb eines Bereichs von 1 bis 5 min bei Drehrohrdurσhmessern im Bereich von 800 bis 3000 mm zu variieren oder gar das Drehrohr ganz anzuhalten oder rück¬ wärts laufen zu lassen, was bei entsprechender Variation der Schneckendrehzahl im Bereich von vorzugsweise 1 bis 10 min eine sehr starke Flexibilität des Drehrohrofens er- möglicht, was dessen Einsatz auf den verschiedenartigsten Gebieten zur Behandlung unterschiedlichster Materialien möglich macht.Finally, with the help of the rotary kiln according to the invention, it is possible to increase the speed of the rotary tube 1 as desired, for example within a range from 1 to 5 minutes with rotary tube diameters in the range from 800 to 3000 mm vary or even stop the rotary tube completely or let it run backwards, which, with a corresponding variation of the screw speed in the range of preferably 1 to 10 minutes, enables the rotary tube furnace to be very flexible, which is its use in the most varied of fields for the treatment of very different materials makes possible.
Besonders geeignet ist der erfindungsgemäße Drehrohrofen für die thermische Behandlung von schlammartigen oder pa- stösen Abfallstoffen, beispielsweise Tankrückständen, durch thermische Zersetzung dieser Materialien unter Luftaus¬ schluß bei Temperaturen im Bereich zwischen etwa 350°C und 650°C zur Rückgewinnung von Energie bzw. wertvollen Roh- Stoffen und zur Reststoff- und Schadstoffminimierung. Ein wesentliches Merkmal der erfindungsgemäßen Lehre ist darin zu sehen, daß die bei solchen Stoffen unvermeidbare Behin¬ derung des Transports durch den Ofen durch sich bildende Klebephasen mit Hilfe der Förderschnecke und durch den Selbstreinigungseffekt der DoppelSchnecke über den form¬ schlüssigen Kontakt von Förderschnecke und Abstreifschnecke erreicht wird. The rotary kiln according to the invention is particularly suitable for the thermal treatment of sludge-like or pasty waste materials, for example tank residues, by thermal decomposition of these materials with the exclusion of air at temperatures in the range between approximately 350 ° C. and 650 ° C. for the recovery of energy or valuable Raw materials and to minimize residues and pollutants. An essential feature of the teaching according to the invention is that the inevitable hindrance to transport through the furnace with such substances is achieved by adhesive phases which form with the aid of the screw conveyor and by the self-cleaning effect of the twin screw via the positive contact between the screw conveyor and the stripping screw becomes.

Claims

P a t e n t a n s p r ü c h e Patent claims
1. Drehrohrofen mit im Inneren des Drehrohrs angeordne¬ ten Fördereinrichtungen, dadurch gekennzeichnet, daß als Fördereinrichtung eine vom Drehrohr (1) unabhängig antreib¬ bare Förderschnecke (2) vorgesehen ist.1. Rotary tube furnace with angeordne¬ th conveyor devices in the interior of the rotary tube, characterized in that a conveyor screw (2) which can be driven independently of the rotary tube (1) is provided as the conveyor device.
2. Drehrohrofen nach Anspruch 1, gekennzeichnet durch eine mit der Förderschnecke (2) in Eingriff stehende und mit ihr gemeinsam antreibbare AbstreifSchnecke (3).2. Rotary tube furnace according to claim 1, characterized by a stripping screw (3) which engages with the screw conveyor (2) and can be driven together with it.
3. Drehrohrofen nach den Ansprüchen 1 oder 2, dadurch gekennzeichnet, daß die Förderschnecke (2) und die Ab¬ streifschnecke (3) identische Abmessungen aufweisen.3. Rotary tube furnace according to claims 1 or 2, characterized in that the screw conveyor (2) and the stripping screw (3) have identical dimensions.
4. Drehrohrofen nach den Ansprüchen 1 bis 3, dadurch gekennzeichnet, daß die vom Eingriffsbereich (4) abgewand¬ ten Außenseiten (5, 6) von Förderschnecke bzw. Abstreif¬ schnecke (3) an der Innenwand (7) des Drehrohrs (1) anlie- gen.4. Rotary tube furnace according to claims 1 to 3, characterized in that the outside (5, 6) of the engaging area (4) of the screw conveyor or stripping screw (3) on the inner wall (7) of the rotary tube (1) issue.
5. Drehrohrofen nach einem der vorhergehenden Ansprü¬ che, dadurch gekennzeichnet, daß die AbstreifSchnecke (3) oberhalb der Förderschnecke (2) angeordnet ist.5. Rotary tube furnace according to one of the preceding claims, characterized in that the stripping screw (3) is arranged above the screw conveyor (2).
6. Drehrohrofen nach den Ansprüchen 1 bis 5, gekenn¬ zeichnet durch Einrichtungen (8, 9, 10, 11, 12, 13, 14) zum unabhängigen Antrieb von Drehrohr (1) einerseits sowie För¬ derschnecke (2) und AbstreifSchnecke (3) andererseits.6. Rotary tube furnace according to claims 1 to 5, gekenn¬ characterized by devices (8, 9, 10, 11, 12, 13, 14) for independent driving of the rotary tube (1) on the one hand and screw conveyor (2) and stripping screw (3rd ) on the other hand.
7. Drehrohrofen nach einem der vorhergehenden Ansprü¬ che, dadurch gekennzeichnet, daß die Förderschnecke (2) und die AbstreifSchnecke (3) aus einem hitzebeständigen und gegenüber den in dem Drehrohrofen zu behandelnden Reak- tionsteilnehmern inerten Material bestehen. 7. Rotary tube furnace according to one of the preceding claims, characterized in that the screw conveyor (2) and the stripping screw (3) consist of a heat-resistant material which is inert towards the reaction participants to be treated in the rotary tube furnace.
EP87900044A 1985-12-03 1986-12-02 Cylindrical rotary kiln Withdrawn EP0248852A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3542699 1985-12-03
DE19853542699 DE3542699A1 (en) 1985-12-03 1985-12-03 TURNTUBES

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EP0248852A1 true EP0248852A1 (en) 1987-12-16

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DE3542699A1 (en) 1987-06-04
WO1987003672A1 (en) 1987-06-18

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