EP0355569A2 - Tunnel furnace for burning materials containing flammable ingredients - Google Patents

Tunnel furnace for burning materials containing flammable ingredients Download PDF

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Publication number
EP0355569A2
EP0355569A2 EP89114624A EP89114624A EP0355569A2 EP 0355569 A2 EP0355569 A2 EP 0355569A2 EP 89114624 A EP89114624 A EP 89114624A EP 89114624 A EP89114624 A EP 89114624A EP 0355569 A2 EP0355569 A2 EP 0355569A2
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EP
European Patent Office
Prior art keywords
furnace
tunnel
zone
sectional area
gas
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EP89114624A
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German (de)
French (fr)
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EP0355569B1 (en
EP0355569A3 (en
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Andreas Hässler
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    • 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
    • F27B9/00—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
    • F27B9/02—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity of multiple-track type; of multiple-chamber type; Combinations of furnaces
    • 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
    • F27B9/00—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
    • F27B9/30—Details, accessories, or equipment peculiar to furnaces of these types
    • F27B9/3005—Details, accessories, or equipment peculiar to furnaces of these types arrangements for circulating gases

Definitions

  • the invention relates to a tunnel kiln for burning combustible material containing combustion material, in which the furnace gas is guided over part of the furnace length in the opposite direction to the conveying direction of the combustion material and has a heating zone at the furnace entrance, a subsequent heating zone and a subsequent high temperature zone, furthermore a subsequent cooling zone extending to the furnace exit.
  • the invention further relates to a method for firing in such a tunnel kiln.
  • the invention is based on the object of designing a tunnel kiln and a method for firing the type which is known as being known in such a way that good exhaust gas quality, in particular with regard to organic substances, can be achieved without extensive outside installations being required to achieve this good exhaust gas quality. Furthermore, the invention has for its object to use the fuel contained in the stock in the furnace economically well.
  • the firing process control should be easier than before, without interfering with the countercurrent heat exchange ratio between the cooling and firing zones.
  • the furnace pressure should be able to be reduced significantly, so that long combustion channels can also be implemented without the need for expensive means such as pressure compensation, water channel sealing or the like.
  • the high free internal cross-section typical of the invention in the heating zone results in favorable furnace gas conditions with low flow rates and correspondingly low delivery resistances through the furnace.
  • the furnace according to the invention therefore requires only little draft and can therefore be built longer than conventional tunnel furnaces. Because of the large internal cross-sectional areas according to the invention, the force required to convey furnace gas is also low. There are also enlarged convection areas.
  • the furnace Since all process-related heat transport takes place within the furnace jacket, the furnace operates with lower fuel requirements than known systems. In addition, the exhaust gas volume, which is no longer dependent on the counterflow ratio in the heating zone, is reduced.
  • the amount of exhaust gas can be controlled with the new tunnel furnace and the new method, preferably based on the oxygen content of the exhaust gas stream.
  • two flow paths are always present in the heating zone, namely one in cocurrent with the firing material, which gives or has given off the heat to the heating zone and another in countercurrent, which supplies the heating zone with heat from combustion processes from the firing zone .
  • the marginal gaps between the inner lining of the furnace and the trimmings in the tunnel furnace i.e. the free internal cross-sectional areas
  • the invention proposes to make the free inner cross-sectional area of the tunnel furnace in the area of the heating zone and possibly the heating zone and possibly part of the firing zone substantially larger than the inner cross-sectional area in the area of the cooling zone which has remained unchanged from the prevailing teaching in the adjoining area of the firing zone.
  • the large free internal cross-sectional areas provided according to the invention can be used to convey large amounts of gas in the longitudinal direction of the furnace. The furnace gas can thus be conveyed within the combustion channel and does not have to be accomplished, as in the case of known special constructions, via external corrosion-prone pipelines.
  • the preheating zone is denoted by A, the heating zone by B, the firing zone by C and the cooling zone by D.
  • large free internal cross-sectional areas are provided within the furnace between the inner wall of the furnace and the facing. These free inner cross-sectional areas, which extend through the entire heating zone to the beginning of the firing zone, can be provided at different locations.
  • the free inner cross-sectional areas or transfer cross-sections are each provided on the side next to the trimmings 2.
  • the free inner cross-sectional area above the facing, that is between the furnace ceiling and the upper edge of the facing is pre-selected see.
  • Another free cross-sectional area is formed in the embodiment according to FIG. 4 by a continuous longitudinal channel provided in the trim.
  • furnace gas flow is effected with gas delivery devices.
  • gas delivery devices 7 are preferably suction jet nozzles or ring jacket nozzles, which have proven to be particularly suitable.
  • the furnace gas flows in a first direction, designated 3. It comes from the firing zone B, flows through the lateral cross-sectional enlargement 1a, passes through the firing material 2 transversely and flows back through the lateral cross-sectional enlargement 1b in the direction of the firing zone B.
  • a first direction designated 3
  • an opposite flow direction 3a is also possible, which is symbolized by dashed arrows.
  • a periodic change between the different flow directions is also possible. More furnace gas should flow in the heating zone than normally flows there in a normal counterflow tunnel furnace. The higher amount of furnace gas is used to supply the stock at this point with the exothermic energy released from combustion processes in combustion zone C.
  • the furnace gas is removed in a high temperature zone, i.e. at the beginning and / or within the combustion zone C.
  • the removal takes place where experience has shown that there are no more carbonization gases, ie at a temperature of approx. 700 to 900 ° C.
  • a plurality of exhaust gas extraction points 4 can be provided, which can be distributed over the entire heating zone and into the combustion zone. These tapping points can have corresponding shut-off devices so that the desired exhaust gas temperature and exhaust gas composition can be achieved.
  • FIG. 3 shows a cross section through the heating zone.
  • the furnace area with the enlarged free inner cross-sectional area is made airtight as a curved sheet steel shell construction.
  • Ceramic fiber mats are provided as insulating mats on the inside of the sheet steel shell construction. The execution in ceramic fiber construction is possible without difficulty because the distance between the trimmings and the inner surface of the furnace is so large that no damage can occur due to falling or protruding firing material on the inside of the furnace wall.
  • the gas flow 3c takes place above the facing 2 in the heating zone B and the backflow 3d takes place through the facing 2, preferably through longitudinal channels, which can also be arranged offset to one another.
  • the embodiment according to FIG. 4 does not require any lateral broadening of the furnace, but merely an increase in the furnace roof in the heating area.
  • FIG. 4 the same parts have the same reference numerals as in FIG. 1.
  • Gas delivery devices 7, which are preferably designed as ring nozzles, are arranged below the furnace ceiling 105. With 8 the chimney is designated and with 9 a fresh air socket for reducing the exhaust gas temperature when used directly for preheating the moldings.
  • FIG. 3 schematically shows the arrangement of lattice walls or perforated walls 10 in the areas with an enlarged free inner cross-sectional area. These can be provided if a shielding of the trimmings 2 from the gas streams 3 and 3a conveyed in the transfer cross sections 1a and 1b seems advisable.
  • the high-temperature zone of the tunnel furnace serves as a thermal afterburning section.
  • the hot furnace gas is withdrawn from the high-temperature zone of the furnace and fed to the heating zone for heating the colder stock.
  • the smoldering gases thus formed in the warming-up zone are transported into the firing zone or a zone of which the temperature is sufficient to cause the smoldering gases to ignite, burn and thus heat in the furnace.
  • the resulting combustion and heating effect in the high temperature zone allows the thermal cleaning of the carbonization gases there and the removal of exhaust gases from this zone.
  • the cleaned exhaust gases removed here when hot can be transported again into the heating zone for heat dissipation.
  • the exhaust gas is not discharged directly from the kiln at the high-temperature extraction point, but rather via lines which run inside the kiln and pass through the entire heating zone and exit the kiln at the beginning thereof.
  • the diagram according to FIG. 5 illustrates the course of the different gas flows.
  • the tunnel kiln designated 11, has three opposing gas flues or gas flow paths within the kiln jacket in the heating zone area.
  • Two throttle cables, 12 and 13 run in opposite directions to each other and are in direct contact with the firing material.
  • Another of a total of three streams, namely stream 14, runs inside the furnace in a line counter to the direction of the firing material.
  • This gas stream 14 can deliver its heat content via the line and through the heat exchanger 17 through which it flows to the heating zone.
  • the third flue gas duct or flue gas flow 14 is formed by the flue gas extraction points 15, the flue gas lines 16a and 16b and by the heat exchangers 17, which in the exemplary embodiment shown are arranged within the furnace jacket, specifically in the areas 1a and 1b. After it has cooled in the heat exchangers 17 in the furnace, the exhaust gas leaves the tunnel furnace via lines 18 after it has given off the sensible heat to the firing stock. The exhaust gas then reaches the ambient air via the chimney 19.
  • the delivery volume of the gas flues 12 and 13 can be regulated and can be larger or smaller than the exhaust gas delivery flow 14 which is guided within the lines 16a and 16b.
  • FIG. 6 shows the temperature curve for the furnace according to FIG. 5.
  • Figure 7 shows an operating diagram with three successive throttle cables.
  • FIG. 8 shows an exemplary cross section with an arrangement of the exhaust pipes 16a and 16b within the furnace jacket 20 with its inner lining 21.
  • the exhaust pipes 16a and 16b serve, up to the heat exchangers 17, for indirect, convective heat dissipation to the furnace trimmings 2.
  • the exhaust gas is removed from there cooled to approx. 700 ° C. It is therefore possible to apply a lower temperature to the heat exchangers and therefore also to produce them in a metallic design.
  • the amount of exhaust gas through line 18 is regulated by means of a fan 23.
  • the indirect exhaust gas duct 14 is thus kept under negative pressure. Circulating means known per se are used between heat exchangers 17 and kiln car stock 2 in order to transfer the heat from the heat exchangers to the kiln car stock and to cool the exhaust gas stream.
  • the tunnel kiln can also be used to clean pollutants that come from the fuels used or the fuel itself. These are essentially halogens and sulfur oxides, which are very reactive at elevated temperatures. For such temperatures of around 500 ° C to 900 ° C, there is enough space in the tunnel furnace for exhaust gas purification to take place inside the furnace.
  • the solid matter filter 24 is therefore provided within the furnace jacket in the enlarged furnace cross-sectional area 1 a.
  • the in Halogens released at a higher temperature range are reacted by the circulating streams 12 and 13 in the colder part of the heating zone with lime or calcareous blanks.
  • the circulation flow 12, 13 can be varied according to the direction and amount, if necessary also periodically reversed. In order to achieve a higher degree of purification, the circulation quantity of the circulation flow can be increased considerably compared to the exhaust gas flow that is removed.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Tunnel Furnaces (AREA)
  • Waste-Gas Treatment And Other Accessory Devices For Furnaces (AREA)
  • Furnace Housings, Linings, Walls, And Ceilings (AREA)
  • Processing Of Solid Wastes (AREA)

Abstract

A tunnel furnace for burning materials containing flammable materials has, in the furnace channel in the region of the burning zone and cooling zone, the usual small free internal cross-sectional area between charge and furnace inner walls. In the region of the heating-up zone and possibly in a part of the burning zone, this free internal cross-sectional area is, in relation to the remaining free internal cross-sectional area, greatly enlarged. In these regions, the separation between charge and furnace wall or furnace roof and charge is thus considerably greater than in the remaining furnace. In the regions with enlarged free internal cross-sectional area, the furnace gas is guided along a longitudinal surface of the charge in counterflow and along another longitudinal surface in co-flow. The furnace gas flows transversely through the charge upon transition from the counterflow to the co-flow. The removal of the furnace gas is carried out at the rear end, seen in the forwarding direction of the materials, of the heating-up zone and/or at the front end of the burning zone. <IMAGE>

Description

Die Erfindung betrifft einen Tunnelofen zum Brennen von verbrennbare Stoffe enthaltendem Brenngut, bei dem das Ofen­gas über einen Teil der Ofenlänge in zur Förderrichtung des Brennguts entgegengesetzter Richtung geführt ist und eine Anwärmzone am Ofeneingang, eine sich anschließende Aufheiz­zone sowie eine danach folgende Hochtemperaturzone aufweist, ferner sich eine anschließende, bis zum Ofenausgang er­streckende Kühlzone. Weiterhin betrifft die Erfindung ein Verfahren zum Brennen in einem derartigen Tunnelofen.The invention relates to a tunnel kiln for burning combustible material containing combustion material, in which the furnace gas is guided over part of the furnace length in the opposite direction to the conveying direction of the combustion material and has a heating zone at the furnace entrance, a subsequent heating zone and a subsequent high temperature zone, furthermore a subsequent cooling zone extending to the furnace exit. The invention further relates to a method for firing in such a tunnel kiln.

Bei brennstoffhaltigen Formlingen, zum Beispiel porosierten Ziegeln, kohlehaltigen oder bituminösen Formlingen, Kohle­elektroden, brennstoffhaltigen Besätzen und dergleichen be­stehen verschiedene Probleme. Einerseits ist es problema­tisch, eine gute Abgasqualität zu erreichen, andererseits ist eine gute wärmewirtschaftliche Ausnutzung des im Besatz enthaltenden Problems schwierig. Dieses Problem besteht be­sonders, wenn die Formlinge aus kohlenwasserstoffhaltigen oder ölhaltigen Böden und Bindeton oder Plastifizierungs­mitteln hergestellt und geformt wurden. Besonders problema­tisch ist es, Formlinge mit einem besonders hohen Anteil an verbrennbaren Substanzen zu brennen. Es kann dabei der Fall auftreten, daß ein höherer Brennstoffanteil im Besatz vor­handen ist, als er zur Führung des Brennprozesses überhaupt erforderlich ist.Various problems exist with fuel-containing moldings, for example porous bricks, carbon-containing or bituminous moldings, carbon electrodes, fuel-containing trimmings and the like. On the one hand it is problematic to achieve a good exhaust gas quality, on the other hand it is difficult to make good use of the problem contained in the stock in the heat economy. This problem arises particularly when the moldings have been produced and molded from hydrocarbon-containing or oil-containing floors and binder clay or plasticizers. It is particularly problematic to burn moldings with a particularly high proportion of combustible substances. It can be the case occur that there is a higher proportion of fuel in the stock than is necessary to guide the combustion process at all.

Alle bisher bekanntgewordenen Tunnelöfen und Verfahren zum Brennen von brennstoffhaltigen Formlingen fordern einen hohen Installationsaufwand. Dabei sind umfangreiche Gasüber­führungsleitungen außerhalb des Ofens vorgesehen. Weiterhin ist es bei den bekannten derartigen Brennverfahren nach­teilig, daß man in das Gegenstrom-Wärmeaustausch-Verhältnis zwischen Kühl- und Brennzone eingreift.All tunnel kilns and methods for burning fuel-containing moldings that have become known require a high installation effort. Extensive gas transfer lines are provided outside the furnace. Furthermore, it is disadvantageous in the known combustion methods of this type that one intervenes in the countercurrent heat exchange ratio between the cooling zone and the combustion zone.

Der Erfindung liegt die Aufgabe zugrunde, einen Tunnelofen und ein Verfahren zum Brennen der als bekannt vorausge­setzten Art so auszubilden, daß eine gute Abgasqualität -insbesondere bezüglich organischer Substanzen- erzielbar ist, ohne daß zum Erreichen dieser guten Abgasqualität um­fangreiche Außeninstallationen erforderlich sind. Weiterhin liegt der Erfindung die Aufgabe zugrunde, den im Besatz ent­haltenen Brennstoff im Ofenraum wärmewirtschaftlich gut zu nutzen. Die Brennprozeßführung soll einfacher als bisher möglich zu gestalten sein, ohne in das Gegenstrom-Wärmeaus­tausch-Verhältnis zwischen Kühl- und Brennzone einzugreifen. Darüberhinaus soll mit dem neuen Verfahren und dem neuen Tunnelofen der Ofendruck wesentlich herabgesetzt werden können, damit auch lange Brennkanäle ausführbar sind, ohne daß hierzu aufwendige Mittel wie Druckkompensation, Wasser­rinnenabdichtung oder dergleichen erforderlich sind.The invention is based on the object of designing a tunnel kiln and a method for firing the type which is known as being known in such a way that good exhaust gas quality, in particular with regard to organic substances, can be achieved without extensive outside installations being required to achieve this good exhaust gas quality. Furthermore, the invention has for its object to use the fuel contained in the stock in the furnace economically well. The firing process control should be easier than before, without interfering with the countercurrent heat exchange ratio between the cooling and firing zones. In addition, with the new method and the new tunnel furnace, the furnace pressure should be able to be reduced significantly, so that long combustion channels can also be implemented without the need for expensive means such as pressure compensation, water channel sealing or the like.

Die Lösung dieser Aufgabe erfolgt mit den Merkmalen des Kennzeichnungsteils von Anspruch 1 bzw. 17.This object is achieved with the features of the labeling part of claims 1 and 17, respectively.

Durch den erfindungstypischen hohen freien Innenquerschnitt in der Aufheizzone ergeben sich günstige Ofengasbedingungen mit geringen Strömungsgeschwindigkeiten und entsprechend geringen Förderwiderständen durch den Ofen. Der erfindungs­gemäße Ofen benötigt deshalb nur geringen Zug und kann dem­zufolge länger gebaut werden als herkömmliche Tunnelöfen. Wegen der erfindungsgemäß groß ausgebildeten Innenquer­schnittsflächen ist auch der Kraftbedarf zur Ofengas­förderung gering. Es ergeben sich außerdem vergrößerte Konvektionsflächen.The high free internal cross-section typical of the invention in the heating zone results in favorable furnace gas conditions with low flow rates and correspondingly low delivery resistances through the furnace. The furnace according to the invention therefore requires only little draft and can therefore be built longer than conventional tunnel furnaces. Because of the large internal cross-sectional areas according to the invention, the force required to convey furnace gas is also low. There are also enlarged convection areas.

Da alle prozeßbedingten Wärmetransporte innerhalb des Ofen­mantels ablaufen, arbeitet der Ofen mit geringerem Brenn­stoffbedarf als bekannte Systeme. Darüberhinaus wird das Ab­gasvolumen, das nicht mehr vom Gegenstromverhältnis in der Anwärmzone abhängig ist, reduziert. Die Abgasmenge kann mit dem neuen Tunnelofen und dem neuen Verfahren vorzugsweise nach dem Sauerstoffgehalt des Abgasstroms geregelt werden.Since all process-related heat transport takes place within the furnace jacket, the furnace operates with lower fuel requirements than known systems. In addition, the exhaust gas volume, which is no longer dependent on the counterflow ratio in the heating zone, is reduced. The amount of exhaust gas can be controlled with the new tunnel furnace and the new method, preferably based on the oxygen content of the exhaust gas stream.

In dem erfindungsgemäßen Tunnelofen und Verfahren sind in der Aufheizzone stets zwei Strömungswege vorhanden, nämlich einer im Gleichstrom mit dem Brenngut, welcher die Wärme an die Aufheizzone abgibt bzw. abgegeben hat und ein weiterer im Gegenstrom, welcher der Aufheizzone Wärme aus Ver­brennungsvorgängen von der Brennzone zuführt.In the tunnel furnace and method according to the invention, two flow paths are always present in the heating zone, namely one in cocurrent with the firing material, which gives or has given off the heat to the heating zone and another in countercurrent, which supplies the heating zone with heat from combustion processes from the firing zone .

Es ist leicht möglich, vorhandene Tunnelöfen auf das neue Verfahren umzurüsten. Hierzu genügt ein Austausch der Auf­heizzone. Dies läßt sich besonders einfach mit vorgefer­tigten Tunnelofenelementen bewerkstelligen.It is easily possible to convert existing tunnel kilns to the new process. An exchange of the heating zone is sufficient for this. This can be accomplished particularly easily with prefabricated tunnel furnace elements.

Im Bereich der Kühl- und Hauptbrennzone muß in den Prozeß­verlauf nicht eingegriffen werden. Dies ist vorteilhaft, weil vor allen Dingen diese Zone für die farbliche und qualitative Beschaffenheit des fertigen Brennprodukts be­stimmend sind. Das neue Verfahren gewährleistet eine ein­wandfreie Qualität der Brennprodukte auch bei Ofenum­stellungen.There is no need to intervene in the course of the process in the area of the cooling and main combustion zone. This is advantageous because, above all, this zone determines the color and quality of the finished fired product. The new process guarantees perfect quality of the fired products even when the furnace is changed.

Nach herrschender Lehre sind die Randspalten zwischen Ofen­innenfutter und Besatz im Tunnelofen, also die freien Innen­querschnittsflächen möglichst klein zu halten. Im Gegensatz zu dieser herrschenden Lehre schlägt die Erfindung vor, die freie Innenquerschnittsfläche des Tunnelofens im Bereich der Aufheizzone und ggfs. der Anwärmzone sowie ggfs. einem Teil der Brennzone wesentlich größer zu gestalten als die gegen­über der herrschenden Lehre unverändert gebliebene Innen­querschnittsfläche im Bereich der Kühlzone und im daran anschließenden Bereich der Brennzone. Die erfindungsgemäß vorgesehenen großen freien Innenquerschnittsflächen können zur Förderung großer Gasmengen in Ofenlängsrichtung genutzt werden. Die Ofengasförderung kann also innerhalb des Brenn­kanals erfolgen und muß nicht wie bei bekannten Sonder­konstruktionen über außenliegende korrosionsanfällige Rohr­leitungen bewerkstelligt werden.According to the prevailing teaching, the marginal gaps between the inner lining of the furnace and the trimmings in the tunnel furnace, i.e. the free internal cross-sectional areas, should be kept as small as possible. In contrast to this prevailing teaching, the invention proposes to make the free inner cross-sectional area of the tunnel furnace in the area of the heating zone and possibly the heating zone and possibly part of the firing zone substantially larger than the inner cross-sectional area in the area of the cooling zone which has remained unchanged from the prevailing teaching in the adjoining area of the firing zone. The large free internal cross-sectional areas provided according to the invention can be used to convey large amounts of gas in the longitudinal direction of the furnace. The furnace gas can thus be conveyed within the combustion channel and does not have to be accomplished, as in the case of known special constructions, via external corrosion-prone pipelines.

Bevorzugte Ausführungsformen der Erfindung sind in den Unteransprüchen beschrieben.Preferred embodiments of the invention are described in the subclaims.

Nachstehend werden bevorzugte Ausführungsformen der Er­findung anhand der Zeichnung im einzelnen beschrieben. Es zeigen:

  • Figur 1 einen schematischen horizontalen Längsschnitt durch eine Ausführungsform des erfindungsge­mäßen Tunnelofens,
  • Figur 2 die Temperaturverlaufskurve in dem Tunnelofen gemäß Figur 1,
  • Figur 3 einen Schnitt entlang Ebene III - III in Figur 1,
  • Figur 4 einen vertikalen Längsschnitt durch eine zweite Ausführungsform des Tunnelofens,
  • Figur 5 einen schematischen Längsschnitt durch eine dritte Ausführungsform des Tunnelofens,
  • Figur 6 eine Temperaturverlaufskurve zum Tunnelofen gemäß Figur 5,
  • Figur 7 einen schematischen Längsschnitt analog Figur 5 durch eine weitere Ausführungsform des Tunnel­ofens,
  • Figur 8 einen Querschnitt durch den Tunnelofen gemäß Figur 5 entlang Ebene VIII - VIII.
Preferred embodiments of the invention are described in detail below with reference to the drawing. Show it:
  • FIG. 1 shows a schematic horizontal longitudinal section through an embodiment of the tunnel furnace according to the invention,
  • FIG. 2 shows the temperature curve in the tunnel furnace according to FIG. 1,
  • FIG. 3 shows a section along plane III-III in FIG. 1,
  • FIG. 4 shows a vertical longitudinal section through a second embodiment of the tunnel furnace,
  • FIG. 5 shows a schematic longitudinal section through a third embodiment of the tunnel furnace,
  • FIG. 6 shows a temperature curve for the tunnel furnace according to FIG. 5,
  • FIG. 7 shows a schematic longitudinal section analogous to FIG. 5 through a further embodiment of the tunnel furnace,
  • 8 shows a cross section through the tunnel furnace according to FIG. 5 along plane VIII - VIII.

Bei den verschiedenen Ausführungsformen ist die Vorwärmzone mit A bezeichnet, die Aufheizzone mit B, die Brennzone mit C und die Kühlzone mit D.In the various embodiments, the preheating zone is denoted by A, the heating zone by B, the firing zone by C and the cooling zone by D.

Bei allen Ausführungsformen werden innerhalb des Ofens zwischen Ofeninnenwand und Besatz große freie Innenquer­schnittsflächen vorgesehen. Diese freien Innenquerschnitts­flächen, die sich durch die gesamte Aufheizzone bis zum Beginn der Brennzone erstrecken, können an verschiedenen Stellen vorgesehen sein. Bei den Ausführungsformen gemäß Figuren 1, 5 und 7 sind die freien Innenquerschnittsflächen oder Überführungsquerschnitte jeweils seitlich neben dem Besatz 2 vorgesehen. Bei der Ausführungsform gemäß Figur 4 ist die freie Innenquerschnittsfläche oberhalb des Besatzes, also zwischen Ofendecke und Oberkante des Besatzes vorge­ sehen. Eine weitere freie Querschnittsfläche ist bei der Ausführungsform gemäß Figur 4 durch einen im Besatz vorge­sehenen durchgehenden Längskanal gebildet. Das Vorsehen der großen freien Innenquerschnittsflächen erlaubt es, daß ent­lang der Aufheizzone genügend Ofengas aus der Brennzone C zur Aufheizzone B und wieder zurück zur Brennzone C trans­portiert werden kann, um durch konvektive Wärmeübertragung auf diese Weise den Besatz in der Aufheizzone zu erwärmen. Die Ofengasströmung wird mit Gasfördereinrichtungen bewirkt. Derartige Gasfördereinrichtungen 7 sind vorzugsweise Saug­strahldüsen oder Ringmanteldüsen, die sich als besonders gut geeignet erwiesen haben.In all embodiments, large free internal cross-sectional areas are provided within the furnace between the inner wall of the furnace and the facing. These free inner cross-sectional areas, which extend through the entire heating zone to the beginning of the firing zone, can be provided at different locations. In the embodiments according to FIGS. 1, 5 and 7, the free inner cross-sectional areas or transfer cross-sections are each provided on the side next to the trimmings 2. In the embodiment according to FIG. 4, the free inner cross-sectional area above the facing, that is between the furnace ceiling and the upper edge of the facing, is pre-selected see. Another free cross-sectional area is formed in the embodiment according to FIG. 4 by a continuous longitudinal channel provided in the trim. The provision of the large free internal cross-sectional areas allows that enough furnace gas can be transported along the heating zone from the firing zone C to the heating zone B and back to the firing zone C in order to heat the stock in the heating zone by convective heat transfer in this way. The furnace gas flow is effected with gas delivery devices. Such gas delivery devices 7 are preferably suction jet nozzles or ring jacket nozzles, which have proven to be particularly suitable.

Aus der Darstellung gemäß Figur 1 ist ersichtlich, daß das Ofengas in einer ersten, mit 3 bezeichneten Richtung strömt. Es kommt aus der Brennzone B, strömt durch die seitliche Querschnittsvergrößerung 1a, durchtritt das Brenngut 2 quer und strömt durch die seitliche Querschnittsvergrößerung 1b in Richtung auf die Brennzone B zurück. Statt dieser mit durchgehenden Pfeilen charakterisierten Strömungsrichtung ist auch eine entgegengesetzte Strömungsrichtung 3a möglich, die mit gestrichelten Pfeilen symbolisiert ist. Es ist auch ein periodischer Wechsel zwischen den unterschiedlichen Strömungsrichtungen möglich. In der Aufheizzone soll mehr Ofengas strömen, als üblicherweise in einem normalen Gegen­stromtunnelofen dort strömt. Die höhere Ofengasmenge dient dazu, um den Besatz an dieser Stelle mit der frei werdenden exothermen Energie aus Verbrennungsvorgängen der Brennzone C zu versorgen.It can be seen from the illustration according to FIG. 1 that the furnace gas flows in a first direction, designated 3. It comes from the firing zone B, flows through the lateral cross-sectional enlargement 1a, passes through the firing material 2 transversely and flows back through the lateral cross-sectional enlargement 1b in the direction of the firing zone B. Instead of this flow direction characterized by solid arrows, an opposite flow direction 3a is also possible, which is symbolized by dashed arrows. A periodic change between the different flow directions is also possible. More furnace gas should flow in the heating zone than normally flows there in a normal counterflow tunnel furnace. The higher amount of furnace gas is used to supply the stock at this point with the exothermic energy released from combustion processes in combustion zone C.

Die Abfuhr des Ofengases erfolgt in einer Zone hoher Temperatur, also am Beginn und/oder innerhalb der Brennzone C. Die Abfuhr erfolgt dort, wo erfahrungsgemäß keine Schwel­gase mehr vorhanden sind, also bei einer Temperatur von ca. 700 bis 900°C. Es können mehrere Abgasentnahmestellen 4 vor­gesehen sein, welche sich über die gesamte Aufheizzone und bis in die Brennzone verteilen können. Diese Entnahmestellen können entsprechende Absperrorgane aufweisen, so daß damit die gewünschte Abgastemperatur und Abgaszusammensetzung erzielbar ist.The furnace gas is removed in a high temperature zone, i.e. at the beginning and / or within the combustion zone C. The removal takes place where experience has shown that there are no more carbonization gases, ie at a temperature of approx. 700 to 900 ° C. A plurality of exhaust gas extraction points 4 can be provided, which can be distributed over the entire heating zone and into the combustion zone. These tapping points can have corresponding shut-off devices so that the desired exhaust gas temperature and exhaust gas composition can be achieved.

Figur 3 zeigt einen Querschnitt durch die Anwärmzone. Dort und aus Figur 1 ist ersichtlich, daß der Ofenbereich mit der vergrößerten freien Innenquerschnittsfläche als gewölbte Stahlblechschalenkonstruktion luftdicht ausgeführt ist. Auf der Innenseite der Stahlblechschalenkonstrution sind Keramikfasermatten als Isolierstoffmatten vorgesehen. Die Ausführung in Keramikfaserkonstruktion ist ohne Schwierig­keiten deshalb möglich, weil der Abstand zwischen Besatz und Ofeninnenfläche so groß ist, daß keine Beschädigungen durch herabfallendes oder überstehendes Brenngut an der Innenseite der Ofenwand entstehen können.Figure 3 shows a cross section through the heating zone. There and from FIG. 1 it can be seen that the furnace area with the enlarged free inner cross-sectional area is made airtight as a curved sheet steel shell construction. Ceramic fiber mats are provided as insulating mats on the inside of the sheet steel shell construction. The execution in ceramic fiber construction is possible without difficulty because the distance between the trimmings and the inner surface of the furnace is so large that no damage can occur due to falling or protruding firing material on the inside of the furnace wall.

Bei der Ausführungsform gemäß Figur 4 erfolgt in der Auf­heizzone B die Gasströmung 3c oberhalb des Besatzes 2 und die Rückströmung 3d erfolgt durch den Besatz 2, vorzugsweise durch Längskanäle, die auch versetzt zueinander angeordnet sein können. Die Ausführungsform gemäß Figur 4 erfordert keine seitliche Ofenverbreiterung sondern lediglich eine Erhöhung der Ofendecke im Aufheizbereich.In the embodiment according to FIG. 4, the gas flow 3c takes place above the facing 2 in the heating zone B and the backflow 3d takes place through the facing 2, preferably through longitudinal channels, which can also be arranged offset to one another. The embodiment according to FIG. 4 does not require any lateral broadening of the furnace, but merely an increase in the furnace roof in the heating area.

In Figur 4 sind gleiche Teile mit gleichen Bezugszeichen wie in Figur 1 bezeichnet. Unterhalb der Ofendecke 105 sind Gas­fördereinrichtungen 7 angeordnet, welche vorzugsweise als Ringdüsen ausgebildet sind. Mit 8 ist der Kamin bezeichnet und mit 9 ein Frischluftstutzen zur Herabminderung der Ab­gastemperatur bei direkter Verwendung zur Vorwärmung der Formlinge.In FIG. 4, the same parts have the same reference numerals as in FIG. 1. Gas delivery devices 7, which are preferably designed as ring nozzles, are arranged below the furnace ceiling 105. With 8 the chimney is designated and with 9 a fresh air socket for reducing the exhaust gas temperature when used directly for preheating the moldings.

Figur 3 zeigt schematisch das Anordnen von Gitterwänden oder durchbrochenen Wänden 10 in den Bereichen mit vergrößerter freier Innenquerschnittsfläche. Diese können dann vorgesehen sein, wenn eine Abschirmung des Besatzes 2 von den in den Überführungsquerschnitten 1a und 1b geförderten Gasströmen 3 und 3a ratsam erscheint.FIG. 3 schematically shows the arrangement of lattice walls or perforated walls 10 in the areas with an enlarged free inner cross-sectional area. These can be provided if a shielding of the trimmings 2 from the gas streams 3 and 3a conveyed in the transfer cross sections 1a and 1b seems advisable.

Bei dem erfindungsgemäßen Verfahren dient die Hochtempera­turzone des Tunnelofens als thermische Nachverbrennungs­strecke. In einem ersten Schritt wird das heiße Ofengas aus der Hochtemperaturzone des Ofens abgezogen und zur Erwärumg des kälteren Besatzes der Aufheizzone zugeführt. Die hier­durch in der Aufwärmzone sich bildenden Schwelgase werden in die Brennzone oder eine solche Zone transportiert, deren Temperatur ausreicht, um die Schwelgase dort zur Zündung, Verbrennung und damit zum Heizen im Ofen zu bringen. Die hierdurch bewirkte Verbrennung und Heizwirkung in der Zone hoher Temperatur erlaubt die thermische Reinigung der Schwelgase dort sowie die Entnahme von Abgasen aus dieser Zone. Es können die in heißem Zustand hier entnommenen ge­reinigten Abgase erneut in die Aufheizzone zur Wärmeabgabe transportiert werden. Dieses grundsätzliche Prinzip ist bei allen Ausführungsbeispielen gleich. Bei den Ausführungs­formen der Tunnelöfen gemäß Figuren 5 bis 7 wird das Abgas an der Entnahmestelle hoher Temperatur nicht unmittelbar aus dem Ofen abgeführt sondern über innerhalb des Ofens geführte Leitungen, die die gesamte Aufheizzone durchsetzen und an deren Beginn aus dem Ofen austreten.In the method according to the invention, the high-temperature zone of the tunnel furnace serves as a thermal afterburning section. In a first step, the hot furnace gas is withdrawn from the high-temperature zone of the furnace and fed to the heating zone for heating the colder stock. The smoldering gases thus formed in the warming-up zone are transported into the firing zone or a zone of which the temperature is sufficient to cause the smoldering gases to ignite, burn and thus heat in the furnace. The resulting combustion and heating effect in the high temperature zone allows the thermal cleaning of the carbonization gases there and the removal of exhaust gases from this zone. The cleaned exhaust gases removed here when hot can be transported again into the heating zone for heat dissipation. This basic principle is in all embodiments the same. In the embodiments of the tunnel kilns according to FIGS. 5 to 7, the exhaust gas is not discharged directly from the kiln at the high-temperature extraction point, but rather via lines which run inside the kiln and pass through the entire heating zone and exit the kiln at the beginning thereof.

Das Schema gemäß Figur 5 veranschaulicht den Verlauf der verschiedenen Gasströme. Der mit 11 bezeichnete Tunnelofen weist drei jeweils gegenläufige Gaszüge oder Gasströmungs­wege innerhalb des Ofenmantels im Aufheizzonenbereich auf. Dabei verlaufen zwei Gaszüge, nämlich 12 und 13 gegenläufig zueinander und stehen in direkter Berührung mit dem Brenn­gut. Ein weiterer von insgesamt drei Strömen, nämlich der Strom 14 verläuft innerhalb des Ofens in einer Leitung ent­gegen der Brenngutdurchlaufrichtung. Dieser Gasstrom 14 kann seinen Wärmeinhalt über die Leitung und über die durch­strömten Wärmetauscher 17 an die Aufheizzone abgeben. Der dritte Abgaszug oder Abgasstrom 14 wird durch die Abgasent­nahmestellen 15, die Abgasleitungen 16a und 16b sowie durch die Wärmetauscher 17 gebildet, welche im dargestellten Aus­führungsbeispiel innerhalb des Ofenmantels und zwar in den Bereichen 1a und 1b angeordnet sind. Nach seiner Abkühlung in den im Ofen liegenden Wärmetauschern 17 verläßt das Abgas den Tunnelofen über Leitungen 18, nachdem es die fühlbare Wärme an den Brennbesatz abgegeben hat. Das Abgas gelangt dann über den Kamin 19 in die Umgebungsluft.The diagram according to FIG. 5 illustrates the course of the different gas flows. The tunnel kiln, designated 11, has three opposing gas flues or gas flow paths within the kiln jacket in the heating zone area. Two throttle cables, 12 and 13, run in opposite directions to each other and are in direct contact with the firing material. Another of a total of three streams, namely stream 14, runs inside the furnace in a line counter to the direction of the firing material. This gas stream 14 can deliver its heat content via the line and through the heat exchanger 17 through which it flows to the heating zone. The third flue gas duct or flue gas flow 14 is formed by the flue gas extraction points 15, the flue gas lines 16a and 16b and by the heat exchangers 17, which in the exemplary embodiment shown are arranged within the furnace jacket, specifically in the areas 1a and 1b. After it has cooled in the heat exchangers 17 in the furnace, the exhaust gas leaves the tunnel furnace via lines 18 after it has given off the sensible heat to the firing stock. The exhaust gas then reaches the ambient air via the chimney 19.

Das Fördervolumen der Gaszüge 12 und 13 kann geregelt werden und größer oder kleiner als der Abgasförderstrom 14 werden, welcher innerhalb der Leitungen 16a und 16b geführt ist.The delivery volume of the gas flues 12 and 13 can be regulated and can be larger or smaller than the exhaust gas delivery flow 14 which is guided within the lines 16a and 16b.

Figur 6 zeigt die Temperaturverlaufskurve zum Ofen gemäß Figur 5.FIG. 6 shows the temperature curve for the furnace according to FIG. 5.

Figur 7 zeigt ein Betriebsschema mit drei aufeinander­folgenden Gaszügen.Figure 7 shows an operating diagram with three successive throttle cables.

Figur 8 zeigt einen beispielhaften Querschnitt mit einer An­ordnung der Abgasleitungen 16a und 16b innerhalb des Ofen­mantels 20 mit dessen Innenfutter 21. Die Abgasleitungen 16a und 16b dienen bis zu den Wärmetauschern 17 der indirekten, konvektiven Wärmeabgabe an den Brennwagenbesatz 2. Damit wird das Abgas dort von ca. 900°C auf ca. 700°C abgekühlt. Es können deshalb die Wärmetauscher mit geringerer Temperatur beaufschlagt und demnach auch in metallischer Ausführung hergestellt werden. Die Abgasmenge durch die Leitung 18 wird mittels eines Ventilators 23 geregelt. Damit wird der indirekte Abgaszug 14 unter Unterdruck gehalten. Zwischen Wärmetauschern 17 und Brennwagenbesatz 2 werden an sich bekannte Umwälzmittel eingesetzt, um die Wärme von den Wärmetauschern auf den Brennwagenbesatz zu übertragen und den Abgasstrom abzukühlen.FIG. 8 shows an exemplary cross section with an arrangement of the exhaust pipes 16a and 16b within the furnace jacket 20 with its inner lining 21. The exhaust pipes 16a and 16b serve, up to the heat exchangers 17, for indirect, convective heat dissipation to the furnace trimmings 2. Thus, the exhaust gas is removed from there cooled to approx. 700 ° C. It is therefore possible to apply a lower temperature to the heat exchangers and therefore also to produce them in a metallic design. The amount of exhaust gas through line 18 is regulated by means of a fan 23. The indirect exhaust gas duct 14 is thus kept under negative pressure. Circulating means known per se are used between heat exchangers 17 and kiln car stock 2 in order to transfer the heat from the heat exchangers to the kiln car stock and to cool the exhaust gas stream.

Der Tunnelofen kann auch zur Reinigung von Schadstoffen her­angezogen werden, die aus den eingesetzten Brennstoffen oder dem Brenngut selbst stammen. Es handelt sich hier im wesent­lichen um Halogene sowie Schwefeloxyde, die bei erhöhten Temperaturen sehr reaktionswillig sind. Für solche Tempera­turen von etwa 500°C bis 900°C steht im Tunnelofen genügend Raum für eine innerhalb des Ofens erfolgende Abgasreinigung zur Verfügung. Bei einer Ausführungsform ist deshalb der Feststoffilter 24 innerhalb des Ofenmantels in dem ver­größerten Ofenquerschnittsbereich 1a vorgesehen. Die im höheren Temperaturbereich freigesetzten Halogene werden durch die zirkulierenden Ströme 12 und 13 im kälteren Teil der Aufheizzone mit Kalk oder kalkhaltigen Rohlingen zur Reaktion gebracht. Die Zirkulationsströmung 12, 13 kann nach Richtung und Menge variiert werden, ggfs. auch periodisch umgekehrt werden. Zur Erreichung eines höheren Reinigungs­grades kann die Umlaufmenge der Zirkulationsströmung gegen­über dem abgeführten Abgasstrom erheblich gesteigert werden.The tunnel kiln can also be used to clean pollutants that come from the fuels used or the fuel itself. These are essentially halogens and sulfur oxides, which are very reactive at elevated temperatures. For such temperatures of around 500 ° C to 900 ° C, there is enough space in the tunnel furnace for exhaust gas purification to take place inside the furnace. In one embodiment, the solid matter filter 24 is therefore provided within the furnace jacket in the enlarged furnace cross-sectional area 1 a. The in Halogens released at a higher temperature range are reacted by the circulating streams 12 and 13 in the colder part of the heating zone with lime or calcareous blanks. The circulation flow 12, 13 can be varied according to the direction and amount, if necessary also periodically reversed. In order to achieve a higher degree of purification, the circulation quantity of the circulation flow can be increased considerably compared to the exhaust gas flow that is removed.

Claims (18)

1. Tunnelofen zum Brennen von verbrennbare Stoffe ent­haltendem Brenngut, bei dem das Ofengas über einen Teil der Ofenlänge in zur Förderrichtung des Brennguts entgegengesetzter Richtung geführt ist und eine An­wärmzone am Ofeneingang, eine sich anschließende Auf­heizzone sowie eine danach folgende Hochtemperaturzone aufweist, ferner eine sich anschließende, bis zum Ofenausgang erstreckende Abkühlzone,
dadurch gekennzeichnet,
daß die freie Innenquerschnittsfläche des Tunnelofens im Bereich der Aufheizzone (B) gegenüber der freien Innenquerschnittsfläche des Tunnelofens in mindestens einem Teil der Brennzone (C) und der Kühlzone (D) we­sentlich vergrößert und daß im Bereich der vergrößer­ten Innenquerschnittsfläche (1a; 1b; 1c) das Ofengas (3) entlang einer Längsfläche des Besatzes (2) im Ge­genstrom und entlang einer anderen Längsfläche des Be­satzes (2) im Gleichstrom zum Brenngut geführt ist, wobei das Ofengas beim Übergang vom Gegenstrom in den Gleichstrom den Besatz (2) quer durchströmt und das Ofengas am in Brenngutförderrichtung gesehen hinteren Ende der Aufheizzone (B) und/oder vorderen Ende der Brennzone (C) dem Ofenkanal entnommen wird.1.Tunnel furnace for burning combustible material containing combustible material, in which the furnace gas is guided over part of the furnace length in the opposite direction to the conveying direction of the combustible material and has a heating zone at the furnace entrance, a subsequent heating zone and a subsequent high temperature zone, as well as a subsequent one , cooling zone extending to the furnace exit,
characterized,
that the free inner cross-sectional area of the tunnel furnace in the area of the heating zone (B) is substantially enlarged compared to the free inner cross-sectional area of the tunnel furnace in at least part of the combustion zone (C) and the cooling zone (D) and that in the area of the enlarged inner cross-sectional area (1a; 1b; 1c) the furnace gas (3) is guided in countercurrent along a longitudinal surface of the stocking (2) and in cocurrent along another longitudinal surface of the stocking (2), the furnace gas flowing transversely through the stocking (2) during the transition from countercurrent to cocurrent and the furnace gas is removed from the furnace duct at the rear end of the heating zone (B) and / or front end of the combustion zone (C), as seen in the direction of the material to be conveyed. 2. Tunnelofen nach Anspruch 1,
dadurch gekennzeichnet,
daß eine vergrößerte freie Querschnittsfläche (1a; 1b) an einer Längsseite des Tunnelofens vorgesehen ist.2. tunnel furnace according to claim 1,
characterized,
that an enlarged free cross-sectional area (1a; 1b) is provided on a long side of the tunnel furnace. 3. Tunnelofen nach Anspruch 1 oder 2,
dadurch gekennzeichnet,
daß eine vergrößerte freie Querschnittsfläche (1c) zwischen Ofendecke (105) und Besatz (2) vorgesehen ist.3. tunnel furnace according to claim 1 or 2,
characterized,
that an enlarged free cross-sectional area (1c) is provided between the furnace ceiling (105) and the facing (2). 4. Tunnelofen nach Anspruch 1 oder 2,
dadurch gekennzeichnet,
daß vergrößerte Querschnittsflächen (1a und 1b) auf einander gegenüberliegenden Längsseiten des Tunnel­ofens vorgesehen sind.4. tunnel furnace according to claim 1 or 2,
characterized,
that enlarged cross-sectional areas (1a and 1b) are provided on opposite longitudinal sides of the tunnel kiln. 5. Tunnelofen nach einem oder mehreren der Ansprüche 1 bis 4,
dadurch gekennzeichnet,
daß innerhalb des Ofenbesatzes (2) ein in Ofenlängs­richtung verlaufender Strömungskanal für das Ofengas vorgesehen ist.5. tunnel furnace according to one or more of claims 1 to 4,
characterized,
that a flow channel for the furnace gas running in the longitudinal direction of the furnace is provided within the furnace stock (2). 6. Tunnelofen nach einem oder mehreren der Ansprüche 1 bis 5,
dadurch gekennzeichnet,
daß im Ofenraum angeordnete Gas-Fördereinrichtungen (7) für die Förderung des Ofengases vorgesehen sind.6. tunnel furnace according to one or more of claims 1 to 5,
characterized,
that gas conveying devices (7) arranged in the furnace chamber are provided for conveying the furnace gas. 7. Tunnelofen nach Anspruch 6,
dadurch gekennzeichnet,
daß die Gasfördereinrichtungen (7) Saugstrahldüsen (Ringmanteldüsen) sind.7. tunnel furnace according to claim 6,
characterized,
that the gas delivery devices (7) are suction jet nozzles (ring jacket nozzles). 8. Tunnelofen nach einem oder mehreren der Ansprüche 1 bis 7,
dadurch gekennzeichnet,
daß das dem Ofenkanal entnommene Ofengas in einer innerhalb des freien Querschnitts (1a; 1b) längs durch die Aufheizzone verlaufenden Leitung (16; 16a; 16b) bis zum Austritt aus dem Ofen geführt ist.8. tunnel furnace according to one or more of claims 1 to 7,
characterized,
that the furnace gas withdrawn from the furnace duct is guided in a line (16; 16a; 16b) which runs longitudinally through the heating zone within the free cross-section (1a; 1b) until it exits the furnace. 9. Tunnelofen nach einem oder mehreren der Ansprüche 1 bis 8,
dadurch gekennzeichnet,
daß in der Abgasleitung (16a; 16b; 16) ein Wärme­tauscher (17) innerhalb des Ofenraums vorgesehen ist.9. tunnel kiln according to one or more of claims 1 to 8,
characterized,
that a heat exchanger (17) is provided in the furnace space in the exhaust pipe (16a; 16b; 16). 10. Tunnelofen nach einem oder mehreren der Ansprüche 1 bis 9,
dadurch gekennzeichnet,
daß innerhalb des vergrößerten freien Ofenquer­schnitts (1a; 1b) ein Feststoffilter (24) zur Ofen­gasreinigung vorgesehen ist.10. tunnel kiln according to one or more of claims 1 to 9,
characterized,
that a solid filter (24) for furnace gas cleaning is provided within the enlarged free furnace cross section (1a; 1b). 11. Tunnelofen nach einem oder mehreren der Ansprüche 1 bis 10,
dadurch gekennzeichnet,
daß der Feststoffilter (24) zum Entfernen von SO₂ ausgebildet ist.11. tunnel furnace according to one or more of claims 1 to 10,
characterized,
that the solid filter (24) is designed to remove SO₂. 12. Tunnelofen nach Anspruch 10,
dadurch gekennzeichnet,
daß der Feststoffilter zum Entfernen von F₂ ausgebil­det ist.12. tunnel furnace according to claim 10,
characterized,
that the solid filter is designed to remove F₂. 13. Tunnelofen nach einem oder mehreren der Ansprüche 1 bis 12,
dadurch gekennzeichnet,
daß das Ofengas innerhalb der Ofenstrecke mit ver­größertem freien Querschnittsbereich (1a; 1b; 1c) vom hinteren Ende der Aufheizzone (B) und/oder vorderen Ende der Brennzone (C) aus der Gleichstromrichtung wieder in Gegenstromrichtung umgeleitet und im Gegen­strom durch den Ofenbereich mit vergrößertem freien Ofenquerschnitt (1a; 1b; 1c) bis zum Austritt aus dem Ofen geführt wird.13. Tunnel furnace according to one or more of claims 1 to 12,
characterized,
that the furnace gas within the furnace section with an enlarged free cross-sectional area (1a; 1b; 1c) from the rear end of the heating zone (B) and / or front end of the firing zone (C) is diverted from the cocurrent direction again in the countercurrent direction and in countercurrent through the furnace area with an enlarged free cross-section of the furnace (1a; 1b; 1c) until it exits the furnace. 14. Tunnelofen nach einem oder mehreren der Ansprüche 1 bis 13,
dadurch gekennzeichnet,
daß die Strömungsrichtungen des Ofengases (3; 3a) in­nerhalb des vergrößerten freien Querschnittsbereichs (1a; 1b; 1c) umkehrbar sind, und zwar gegebenenfalls periodisch.14. tunnel furnace according to one or more of claims 1 to 13,
characterized,
that the directions of flow of the furnace gas (3; 3a) within the enlarged free cross-sectional area (1a; 1b; 1c) are reversible, if necessary periodically. 15. Tunnelofen nach einem oder mehreren der Ansprüche 1 bis 14,
dadurch gekennzeichnet,
daß mindestens im vergrößerten Querschnittsbereich der Tunnelofen als Stahlblechschalenkonstruktion mit innerer Isolierstoffschicht ausgebildet ist.15. tunnel furnace according to one or more of claims 1 to 14,
characterized,
that at least in the enlarged cross-sectional area of the tunnel furnace is designed as a sheet steel shell construction with an inner layer of insulating material. 16. Tunnelofen nach einem oder mehreren der Ansprüche 1 bis 15,
dadurch gekennzeichnet,
daß seitlich neben dem Besatz (2) innerhalb des ver­größerten freien Querschnittsbereichs (1a; 1b) paral­lel sich zum Besatz (2) erstreckende durchbrochene Wände (10) vorgesehen sind.16. tunnel furnace according to one or more of claims 1 to 15,
characterized,
that perforated walls (10) extending laterally next to the trim (2) within the enlarged free cross-sectional area (1a; 1b) are provided parallel to the trim (2). 17. Verfahren zum Brennen von verbrennbare Stoffe enthal­tendem Brenngut, bei dem das Ofengas über einen Teil der Ofenlänge in zur Förderrichtung des Brennguts entgegengesetzter Richtung geführt ist und eine An­wärmzone am Ofeneingang, eine sich anschließende Aufheizzone sowie eine danach folgende Hochtempera­turzone aufweist, ferner eine sich anschließende, bis zum Ofenausgang sich erstreckende Abkühlzone,
dadurch gekennzeichnet,
daß die freie Innenquerschnittsfläche des Tunnelofens im Bereich der Aufheizzone (B) gegenüber der freien Innenquerschnittsfläche des Tunnelofens in mindestens einem Teil der Brennzone (C) und der Kühlzone (D) we­sentlich vergrößert und daß im Bereich der vergrößer­ten Innenquerschnittsfläche (1a; 1b; 1c) das Ofengas (3) entlang einer Längsfläche des Besatzes (2) im Ge­genstrom und entlang einer anderen Längsfläche des Besatzes (2) im Gleichstrom zum Brenngut geführt ist, wobei das Ofengas beim Übergang vom Gegenstrom in den Gleichstrom den Besatz (2) quer durchströmt und das Ofengas am in Brenngutförderrichtung gesehen hinteren Ende der Aufheizzone (B) und/oder vorderen Ende der Brennzone (C) dem Ofenkanal entnommen wird.17. A method for burning combustible material containing combustible material, in which the furnace gas is guided over part of the furnace length in the opposite direction to the conveying direction of the combustible material and has a heating zone at the furnace entrance, a subsequent heating zone and a subsequent high temperature zone, and also a subsequent one , cooling zone extending to the furnace exit,
characterized,
that the free inner cross-sectional area of the tunnel furnace in the area of the heating zone (B) is substantially enlarged compared to the free inner cross-sectional area of the tunnel furnace in at least part of the combustion zone (C) and the cooling zone (D) and that in the area of the enlarged inner cross-sectional area (1a; 1b; 1c) the furnace gas (3) is guided in countercurrent along a longitudinal surface of the stocking (2) and in cocurrent along another longitudinal surface of the stocking (2), the furnace gas flowing transversely through the stocking (2) during the transition from countercurrent to cocurrent and the furnace gas is removed from the furnace duct at the rear end of the heating zone (B) and / or front end of the combustion zone (C), as seen in the direction of the material to be conveyed. 18. Verfahren zum Brennen nach Anspruch 17,
dadurch gekennzeichnet,
daß ein Tunnelofen nach einem oder mehreren der An­sprüche 1 bis 16 verwendet wird.18. A method of burning according to claim 17,
characterized,
that a tunnel kiln according to one or more of claims 1 to 16 is used.
EP89114624A 1988-08-09 1989-08-08 Tunnel furnace for burning materials containing flammable ingredients Expired - Lifetime EP0355569B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT89114624T ATE97226T1 (en) 1988-08-09 1989-08-08 TUNNEL FURNACE FOR FIRING FUEL CONTAINING COMBUSTIBLE MATERIALS.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3826957A DE3826957A1 (en) 1988-08-09 1988-08-09 MULTI-CURRENT - LOW PRESSURE - TUNNEL STOVE WITH INTEGRATED THERMAL EXHAUST GAS CLEANING
DE3826957 1988-08-09

Publications (3)

Publication Number Publication Date
EP0355569A2 true EP0355569A2 (en) 1990-02-28
EP0355569A3 EP0355569A3 (en) 1990-12-27
EP0355569B1 EP0355569B1 (en) 1993-11-10

Family

ID=6360489

Family Applications (1)

Application Number Title Priority Date Filing Date
EP89114624A Expired - Lifetime EP0355569B1 (en) 1988-08-09 1989-08-08 Tunnel furnace for burning materials containing flammable ingredients

Country Status (3)

Country Link
EP (1) EP0355569B1 (en)
AT (1) ATE97226T1 (en)
DE (2) DE3826957A1 (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4023432A1 (en) * 1989-10-18 1991-04-25 Werner Ing Grad Strohmenger Tunnel kiln - with heat exchangers for preheating gas circuit fed by hot gases from cooling zone
DE4016227A1 (en) * 1990-05-19 1991-11-21 Haessler Andreas Dipl Ing Fh Tunnel kiln has initial drier - to dry brick blanks and burn off residue in continuous passage into kiln
DE102011100736A1 (en) 2011-05-06 2012-11-08 Andreas Hässler Method for operating e.g. tunnel furnace used for firing brick, involves directing exhaust gas stream from tunnel furnace to waste heat boiler for generating electric power utilized for drying and heating processes of furnace

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2525101A (en) * 1946-06-13 1950-10-10 Ferro Enamel Corp Kiln structure
BE677112A (en) * 1965-03-01 1966-07-18 Andreas Haessler Firing process and device for carrying out this process for driving continuous circulation furnaces for ceramic products
DE1583457A1 (en) * 1965-03-01 1970-08-06 Andreas Haessler Process for the continuous reducing firing of ceramic products

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2525101A (en) * 1946-06-13 1950-10-10 Ferro Enamel Corp Kiln structure
BE677112A (en) * 1965-03-01 1966-07-18 Andreas Haessler Firing process and device for carrying out this process for driving continuous circulation furnaces for ceramic products
DE1583457A1 (en) * 1965-03-01 1970-08-06 Andreas Haessler Process for the continuous reducing firing of ceramic products

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4023432A1 (en) * 1989-10-18 1991-04-25 Werner Ing Grad Strohmenger Tunnel kiln - with heat exchangers for preheating gas circuit fed by hot gases from cooling zone
DE4016227A1 (en) * 1990-05-19 1991-11-21 Haessler Andreas Dipl Ing Fh Tunnel kiln has initial drier - to dry brick blanks and burn off residue in continuous passage into kiln
DE102011100736A1 (en) 2011-05-06 2012-11-08 Andreas Hässler Method for operating e.g. tunnel furnace used for firing brick, involves directing exhaust gas stream from tunnel furnace to waste heat boiler for generating electric power utilized for drying and heating processes of furnace

Also Published As

Publication number Publication date
DE3826957A1 (en) 1990-02-15
DE58906149D1 (en) 1993-12-16
EP0355569B1 (en) 1993-11-10
ATE97226T1 (en) 1993-11-15
EP0355569A3 (en) 1990-12-27

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