WO1995015472A1

WO1995015472A1 - Process for firing formed ceramic bodies and installation for carrying out the process

Info

Publication number: WO1995015472A1
Application number: PCT/EP1994/003967
Authority: WO
Inventors: Walter Rieger
Original assignee: Keller Gmbh
Priority date: 1993-12-01
Filing date: 1994-11-30
Publication date: 1995-06-08
Also published as: AU1108595A; ATA243993A; EP0731901A1; AT401817B; DE4442850A1; PL314842A1

Abstract

In a process for firing formed ceramic bodies, the formed bodies are conveyed through a heating zone, a firing zone and a cooling zone, with the formed bodies in the heating zone moving in the opposite direction to formed bodies of a cooling zone that is situated parallel to the heating zone and that forms a common circuit with the heating zone. To save energy and to exploit optimally the naturally occuring transmission of heat, the formed bodies are transported through the zones layered in multiple, mutually parallel disk-wall stacks (21), such that a disk-wall stack (21) conveyed in one direction through the heating and cooling zone travels closely adjacent to a disk-wall stack (21) conveyed in the opposite direction, thus entailing intensive radiant heat transmission.

Description

Process for firing ceramic moldings and plant for carrying out the process

The invention relates to a method for firing ceramic moldings, in particular bricks, by guiding the moldings through a heating zone, a firing zone and a cooling zone, the moldings in the heating zone opposite to moldings having a channel arranged parallel to the heating zone and a common channel with the heating zone forming cooling zone are moved, as well as a plant for performing the method.

A method of this type is known from DE-A-25 51 811. Here, the moldings are packed in large quantities tightly in stacks, so that heating can be slow. In order to avoid heat losses, such as occur in a conventional type of tunnel kiln, in which the moldings are guided in countercurrent to the kiln gases, DE-A-25 51 811 strives to improve the gas flow within the kiln, etc. by setting a stationary atmosphere in the longitudinal direction of the furnace channel in the heating zone and in the cooling zone, a strong circulation taking place in sections transverse to the longitudinal direction of the channel between a section of the cooling zone and a corresponding section of the heating zone

As a result of this revolution, temperature differences between the cooling zone and the heating zone within a longitudinal section of the tunnel kiln can be kept low, as a result of which fuel can be saved, but this temperature compensation requires a considerable amount of time and, moreover, there is a risk of very uneven application of heat, since the Moldings arranged at the edges are exposed to a much greater thermal load than the internal moldings due to radiation heat transfer. In order to avoid this, it is necessary with the known method to make the circulation as vigorous as possible. In order to trot to achieve a temperature distribution as uniform as possible in the stack of moldings, according to DE-A-25 51 811, regulating plates are provided on the ceiling of the tunnel furnace, by means of which the flow between the stack of moldings is as uniform as possible.

The invention aims to avoid these disadvantages and difficulties and has as its object to provide a method and a system for performing the method with which it is possible with high energy savings to get by without or with only very little artificially generated transverse circulation. In particular, the naturally occurring heat transfer by body radiation or gas radiation and heat convection should be optimally used.

DOCUMENTS This object is achieved in a method of the type described in the introduction in that the moldings are transported through the zones to a plurality of narrow, parallel facing, preferably each having a width corresponding to the length of a molding, layered panel walls, one in one direction through the zones Heating zone and cooling zone of the facing disk wall is moved closely adjacent to a facing disk wall guided in the opposite direction with intensive radiant heat transfer.

According to the invention, the material flows formed by the formations are finely fanned out through the heating zone, firing zone and cooling zone, with a material flow coming into the system coming to lie between outgoing material flows Moldings contained heat content by radiation.

From DE-A - 31 16 435 a kiln for burning wet moldings is known, the moldings migrating into the firing zone in a single arrangement due to their low strength and the hot products coming from the firing zone in the opposite direction to the still unbaked goods next to and / or migrate above or below it, releasing its thermal energy while cooling the unbaked goods before they enter the firing zone and drying these goods. Here drying and firing take place in the same channel. The kiln serves as a heat exchanger, since a molding coming from the firing zone runs next to each foam molding entering the firing zone. The heat transfer takes place in the form of flow heat.

According to the invention, facing disk walls are preferably formed, the thickness of which corresponds at most to the largest dimension of a molding. The moldings can be stacked crosswise to form the trimming panel walls, whereby a high stability of a trimming panel wall is achieved.

Trimming panel walls are expediently formed, the ratio of thickness to height of which is in a range between 1: 1 and 1: 6, preferably between 1: 1 and 1: 4. This ensures a high throughput through the system with sufficient stability.

The facing disk walls are preferably moved in a manner known per se through the heating zone to the firing zone along a first path, converted to an adjacent path in the firing zone and through the cooling zone along the adjacent path opposite to the direction in which the trimming panel walls were led through the heating zone, the material flows can be easily manipulated, since the molded articles are fed into the system and the molded products are removed from the system after the firing process on one and the same side the system can take place.

Preferably, between the heating zone and the firing zone or between the firing zone and the cooling zone, furnace gas is drawn off both from the heating zone and from the firing zone and an initial area of the heating zone, etc. an application zone, in turn fed, whereby it is possible to use a large part of the furnace gas as heat transfer medium. The furnace gas is largely circulated and is only in

the extent excreted from the system as oxygen or fresh air must be supplied for the burning process.

Preferably, the hot furnace gas supplied to the heating zone is fed to this zone in a decreasing amount as the length progresses, as a result of which the moldings are heated up particularly gently and gently

To further save energy, fresh air is expediently preheated and the preheated fresh air is fed to the combustion zone

According to a preferred embodiment, in order to achieve a favorable temperature profile in the firing zone, the preheated fresh air supplied to the firing zone is increasing in increasing quantity as the length of the firing zone progresses - u.zw. to the reversal area - fed.

In order to burn moldings mixed with burn-out substances, fresh air preheated by the furnace gas is fed to the heating-up zone in a burning-out zone which follows the initial region of the heating zone. In order to achieve a quick and effective ignition of the burn-out substances contained in the moldings, the preheated fresh air supplied to the burn-out zone is expediently supplied in decreasing quantity as the length of the burn-out zone progresses.

Fresh air preheated by the furnace gas is advantageously fed to at least one burner in the combustion zone

Excess fresh air preheated by the furnace gas in the method according to the invention is expediently fed to a drying oven

According to a particularly advantageous embodiment, extracted furnace gas is fed to the combustion zone, preferably via a mixing chamber arranged in the area in which the moldings are reversed. This makes it possible, particularly in connection with returning the furnace gas to the heating zone, to use a very large part of the furnace gas as the heat transfer medium. In this way, it is possible to recycle up to 80% of the furnace gas as a heat transfer medium in the process during the burning of burned-out moldings. As a result, only small amounts of exhaust gas are generated and considerable energy savings, etc. in the order of up to 75% in total. The fresh air supply is then used exclusively for heat conversion, i.e. to maintain the actual combustion processes. The extracted furnace gas can also be fed to a drying oven instead of being discharged through a chimney after any cleaning that may be required (in particular when burning pollutant-emitting moldings).

Heavy oil or alternative fuels such as sewage sludge etc. are advantageously used as fuel.

A system for carrying out the decay, with a tunnel furnace having a heating zone, a combustion zone and a cooling zone and with a plurality of bogie car trains which can be moved through the tunnel oven, a bogie car train being movable in the opposite direction to an adjacent bogie car train is characterized in that a bogie car train is formed Kiln cars are each designed to accommodate a maximum of two side panel walls arranged side by side. The kiln cars used according to the invention are thus very narrow and light; in particular if the kiln cars are each designed only to accommodate a single trimming disk wall, the width of a kiln car being only slightly wider than the maximum largest dimension of a molding. They are then particularly easy to manipulate.

The tunnel kiln is preferably designed as a reversing tunnel kiln, at one end of which there is an unloading and loading station for the kiln cars and at the other end of which a kiln car transfer station located in the burning zone for converting the kiln cars to exit lanes arranged in parallel with entry lanes for the kiln cars is arranged. Due to the light construction of the kiln cars, moving them inside the reversing tunnel kiln is not difficult.

A preferred embodiment is characterized in that between the heating zone and the firing zone or between the firing zone and the cooling zone, an oven gas suction channel opens into the interior of the oven, which has a first branch channel that leads to an initial region of the heating zone, etc. a warming-up zone of the same, is guided and opens there via one or more orifices distributed over the length of the warming-up zone and has a second branch duct which leads to an exhaust gas chimney, a third branch duct of the furnace gas suction duct expediently entering the combustion zone, preferably in a mixing chamber of the combustion zone arranged at the end of the reversing tunnel furnace opens

In this case, the furnace gas suction channel is advantageously designed as a recuperator for heating fired air, which is fed in through a fresh air supply line, the fresh air supply line being designed as a jacket duct surrounding the furnace gas suction channel In the fresh air supply line, the fresh air is preferably conducted in a first recuperator part in countercurrent to the furnace gas sensed in the first branch duct, and the preheated fresh air can be supplied at least in part to a burn-out zone following the heating zone of the heating zone via branch lines.

In order to save energy, the fresh air supplied in the fresh air supply line is expediently conducted in a second recuperator part in cocurrent to the furnace gas flowing in the second branch duct and can at least partly be supplied to the combustion zone via branch lines.

To supply at least one burner with air, the fresh air supply line preferably opens into the burner with a branch line, so that the burner is supplied with preheated fresh air

The fresh air supply line preferably opens into a drying oven.

To support natural convection, it may be expedient that hot air driving nozzles for supplying preheated fresh air are provided in the side walls of the tunnel furnace in the heating zone and in the cooling zone.

For this purpose, high-pressure burners can also be provided in the side walls of the tunnel furnace in the heating zone and in the cooling zone and, if appropriate, in the firing zone.

Due to the particularly light design of the kiln cars of the system according to the invention, the kiln cars can be guided on rail tracks arranged in the interior of the tunnel kiln by means of high-temperature-resistant castors which are arranged on the underside of a refractory bogie car body, the bottom of the tunnel kiln advantageously being guided by one sealing cover plate is formed

To avoid air currents below the bogie wagons, web plates protruding at the level of the bogie car body, which extend in the longitudinal direction of the rail balers, are expediently provided on the floor of the tunnel furnace between adjacent railways, and the rollers also protrude from the bogie car body downwards to the floor of the tunnel furnace Shielding plates, which extend in the form of circumferential sheet metal aprons along and across the longitudinal direction of the rail tracks, surround. So that natural convection can take place as unhindered as possible, the facing disk walls can advantageously be supported on chamotte-transverse tension sole stones.

A combustion chamber for the combustion of secondary fuel is expediently provided with an ash discharge device which is shielded from the combustion zone by a flame protection wall

The invention is explained in more detail below with reference to the drawing using an exemplary embodiment, wherein FIG. 1 shows the floor plan of a reversing tunnel furnace according to the invention with the ceiling removed in a schematic illustration. FIG. 2 also shows a longitudinal vertical section through the tunnel furnace according to the invention in a schematic illustration. 3 illustrates the average temperature conditions prevailing in the interior of the furnace and the magnitude of the heat capacities (hatched areas) which build up during the firing process. Fig. 4 shows a partial cross section through the reversing tunnel furnace according to the invention, wherein clinker is stacked as moldings on the bogie. Fig. 5 shows a side view of a furnace car provided with trimmings. 6 and 7 illustrate, in a representation analogous to FIGS. 4 and 5, a stock for plate-shaped moldings. 8 shows the convection flow on a schematically illustrated cross section through the furnace according to the invention. FIG. 9 shows an auxiliary brick in oblique view.

1 designates a reversing tunnel furnace of the system according to the invention, in the interior 2 of which a heating zone 3, a combustion zone 4 and a cooling zone 5 are provided. Through the interior 2 of the reversing tunnel furnace, a plurality of bogie car trains 6 can be moved in the longitudinal direction thereof - according to the exemplary embodiment shown in the figures, there are six bogie car trains 6, each of which a bogie car train 6 is movable in the opposite direction to an adjacent bogie car train 6 along rail tracks 7, and the like .zw. in the following way:

Each of the bogie wagons 8 forming a bogie wagon train 6 are or the like on a with a lifting gate. The lockable end 9 of the reversing tunnel furnace is equipped with the moldings 10 to be fired in a special manner (to be described below) and then along every second rail track 7, the so-called entrance railways 11, through the respective heating zone 3 to the firing zone 4 arranged at the other end 12 of the reversing tunnel furnace 1 method. There, in a transfer station 13, the mechanics of which are arranged in a room 14 below the reversing tunnel kiln 1, the kiln cars 8 are transferred to the respectively adjacent rail track 7, the so-called exit lanes 15, whereupon the kiln cars 8 pass through the respective cooling zone 5 from the reversing tunnel kiln 1 pulled out - 7 -

So that natural convection can take place as freely as possible, the facing disk walls can advantageously be supported on chamotte-transverse tension sole stones.

Suitably, a combustion chamber for combustion of secondary fuel with a Ascheaustrageinrichtung is ^provided, against d ^- e combustion zone is shielded with a flame protection wall

The invention is explained in more detail below with reference to the drawing using an exemplary embodiment, FIG. 1 schematically showing the outline of a reversing tunnel furnace according to the invention with the ceiling removed. FIG. 2 shows a longitudinal vertical section through the tunnel furnace according to the invention likewise in a schematic representation. 3 illustrates the average temperature conditions prevailing in the interior of the furnace and the magnitude of the heat capacities (hatched areas) which build up during the firing process. Fig. 4 shows a partial cross section through the reversing tunnel furnace according to the invention, wherein clinker is stacked as moldings on the bogie. Fig. 5 shows a side view of a furnace car provided with trimmings. 6 and 7 illustrate, in a representation analogous to FIGS. 4 and 5, a stock for plate-shaped moldings. 8 shows the convection flow on a schematically illustrated cross section through the furnace according to the invention. FIG. 9 shows an auxiliary brick in oblique view.

1 designates a reversing tunnel furnace of the system according to the invention, in the interior 2 of which a heating zone 3, a combustion zone 4 and a cooling zone 5 are provided. Through the interior 2 of the reversing tunnel furnace, a plurality of bogie car trains 6 are movable in its longitudinal direction - according to the exemplary embodiment shown in the figures, there are six bogie car trains 6, one bogie car train 6 each being movable in the opposite direction to an adjacent bogie car train 6 along rail tracks 7, and the like .zw. in the following way:

Each of the bogie wagons 8 forming a bogie wagon train 6 are connected to a lift gate or the like. The lockable end 9 of the reversing tunnel furnace is equipped with the moldings 10 to be fired in a special manner (to be described below) and then arranged along every second rail track 7, the so-called entrance tracks 11, through the respective heating zone 3 to the other end 12 of the reversing tunnel furnace 1 Move firing zone 4. Then, in a transfer station 13, the mechanics of which are arranged in a room 14 below the reversing tunnel furnace 1, the furnace cars 8 are transferred to the respectively adjacent rail track 7, the so-called exit tracks 15, whereupon the furnace cars 8 pass through the respective cooling zone 5 from the reversing tunnel furnace 1 pulled out pictured to use. Such a filler auxiliary stone 18, which has the cross section of a double comb, ensures narrow contact surfaces on the moldings, so that only minor surface portions of the moldings 10 are not directly coated by furnace gas. This ensures a complete burn-out of the burn-out substances contained in the moldings. Furthermore, such auxiliary stones 18 cause a substantially freer convection flow, in particular in the transverse direction, whereby the

Heat transfer ratios between adjacent trimming panel walls can be significantly improved. A transverse convection flow is formed, as illustrated by arrows 27 in FIG. 8

The end end wall 28 of the reversing tunnel kiln 1, which closes the combustion zone 4, is formed by a hot air distributor wall, behind which there is a high-temperature mixing chamber 29, in which the hot flame gases coming from the burner 30 (or several burners 30), as described later, recycle furnace gas. This makes it possible to drive the burner or burners 30 with a high flame temperature, as is formed in purely stoichiometric combustion, and nevertheless to be able to regulate the temperature of the hot gases entering the combustion zone 4 as required.

According to the invention, it is therefore possible to work with a very high combustion temperature, so that even heavy petroleum oils and / or secondary fuels can be burned properly. This results in a large cost, especially since heavy oil and secondary fuels are much cheaper than natural gas. Another advantage of purely stoichiometric combustion is the fact that the fresh air required for the combustion can be minimized, which also minimizes the exhaust gas volume

In the area between the heating zone 3 and the firing zone 4 or between the firing zone 4 and the cooling zone 5, an oven gas suction channel 31 opens into the furnace interior 2, which is surrounded by a jacket-like air supply channel 32 with the formation of a recuperator for heating fresh air Furnace gas extraction duct 31 has a first branch duct 33, which is guided above the reversing tunnel furnace 1 in the direction of the closable end 9 of the reversing tunnel furnace 1. This first branch duct 33 opens out into the starting area of the heating zone 3 with a plurality of outlets 34 distributed over the length of the reversing tunnel furnace 1 , hereinafter referred to as heating zone 3 '. Part of the furnace gas is thus guided through the heating zone 3 in the circuit via these orifices 34, fans 34 being arranged upstream of the orifices 34 to support and regulate this circuit. These fans 35 operate in such a way that the hot furnace gas supplied to the heating zone 3 'progressively increases in length pictured use. Such a filler auxiliary stone 18, which has the cross section of a double comb, ensures narrow contact surfaces on the moldings, so that only minor surface portions of the moldings 10 are not directly coated by furnace gas. This ensures complete burnout of the burn-out substances contained in the moldings. Furthermore, such auxiliary stones 18 cause a substantially freer convection flow, in particular in the direction of rotation, whereby the

The end wall 28 of the reversing tunnel kiln 1, which closes the firing zone 4, is formed by a hot air distributor wall, behind which there is a high-temperature mixing chamber 29 in which the hot ram gases coming from the burner 30 (or several burners 30), as described later, in Circulated furnace gas can be mixed. This makes it possible to drive the burner or burners 30 with a high flame temperature, as is formed in purely stoichiometric combustion, and nevertheless to be able to regulate the temperature of the hot gases entering the combustion zone 4 as required.

In the area between the heating zone 3 and the firing zone 4 or between the firing zone 4 and the cooling zone 5, an oven gas suction channel 31 opens into the furnace interior 2, which is surrounded by a jacket-like air supply channel 32 with the formation of a recuperator for heating fresh air Furnace gas extraction duct 31 has a first branch duct 33, which is guided above the reversing tunnel furnace 1 in the direction of the closable end 9 of the reversing tunnel furnace 1. This first branch duct 33 opens out into the starting area of the heating zone 3 with a plurality of outlets 34 distributed over the length of the reversing tunnel furnace 1 , hereinafter referred to as heating zone 3 '. Part of the furnace gas is thus circulated through these orifices 34 via the heating zone 3, blowers 35 being arranged upstream of the orifices 34 to support and regulate this circuit. These fans 35 operate in such a way that the hot furnace gas supplied to the heating zone 3 'progressively increases in length Likewise, fresh air preheated by the furnace gas is fed into the combustion zone via branch lines 47 starting from the fresh air supply duct 32, and so on. with decreasing amounts with increasing length of the firing zone 4. Blowers 48 are also provided in these branch lines 47 to regulate the fresh air quantities supplied.

As can be seen from FIG. 2, the fresh air preheated by the furnace gas is guided along the first branch duct 33 in countercurrent to the furnace gas and along the second branch duct 37 in cocurrent to the furnace gas

The fresh air necessary for the operation of the burner (s) 30 is also taken from the fresh air supply duct 32, etc. via a branch line 49 and via a fan 50 to the burner (s) 30

Any excess preheated fresh air that is present can be fed to a drying oven 53 via a further branch line 51 and a blower 52. In this branch line 51 there is also a supply of preheated fresh air or of pure furnace exhaust gas in the heat exchanger 40, which is arranged upstream of the exhaust gas chimney 38. The exhaust gas purification system 39 arranged upstream of the exhaust gas chimney is particularly functional when the fire releases pollutants for which it is necessary to clean the furnace gas (for example dry sorption of acidic gas components) before it is discharged through the chimney 38 or fed to the drying oven 53 .

The design of the "tube-in-tube" jacket recuperator 31, 32 is extremely advantageous because the reversing tunnel kiln 1 is an elongated base body, the length of the recuperator can be adapted well to its length, and because the individual gas routing outlets and entrances along the entire reversing tunnel kiln 1 must be installed.

In addition, the hot furnace circulating gases in the inner, large-diameter furnace gas suction channel 31 (easily cleaned from deposits, such as dust, etc. through manhole entrances), so that no overheating can occur due to the jacket cooling by means of fresh air. Another advantage of the recuperator 31, 32 is the fact that no complex heat insulation devices are required.

According to a variant of the method according to the invention, the natural convection flow shown in FIG. 8, which is caused by the gas rising pressure on the warmer side, can be supported by a forced convection flow in order to achieve a higher heat transfer. For this purpose, hot gas driving nozzles 54 arranged in the side walls of the reversing tunnel furnace 1 serve through which the furnace gas flows 1 1

Likewise, fresh air preheated by the furnace gas is fed into the combustion zone via branch lines 47 starting from the fresh air supply duct 32, and so on. with decreasing amounts with increasing length of the firing zone 4. Blowers 48 are also provided in these branch lines 47 to regulate the fresh air quantities supplied.

The design of the "tube in tube" jacket recuperator 31, 32 is extremely advantageous because the reversing tunnel kiln 1 is an elongated base body, the length of the recuperator can be adapted well with its length and because the individual gas routing and access along the entire reversing tunnel kiln 1 must be installed.

According to a variant of the method according to the invention, the natural convection flow shown in FIG. 8, which is caused by the gas rising pressure on the warmer side, can be supported by a forced convection flow in order to achieve a higher heat transfer. For this purpose, hot gas drive nozzles 54 arranged in the side walls of the reversing tunnel furnace 1 serve through which the furnace gas flows 13

The system according to the invention has the advantage that the lighting can be accomplished particularly easily. Only the burner or burners 30 and the furnace gas circulation need to be put into operation. The control of these devices is considerably simplified compared to conventional tunnel furnaces, since the burners 30 are only arranged at one point. In this way, the system according to the invention can, for example, be brought into a temperature-reduced steady-state operation over the weekend and can be started up for the combustion operation in a short time after the weekend.

The system according to the invention can also be integrated relatively well into existing tunnel kiln systems, in that only the bogie car park is matched to the respective product and a new burner duct substructure is built. By creating a better heat transfer, in addition to significantly shorter burning times, the other enormous advantages of energy saving via recuperative furnace gas recycling, reducing exhaust gas loss, avoiding false air and avoiding heat radiation losses from the large and heavy bogie wagon bodies - often outside of the day The firing channel awaits its loading and unloading on the sidings and cools completely - be fully used.

Another enormous advantage also results from the fact that the system according to the invention has been converted to alternative energy uses, such as wood flour, straw, paper sludge and municipal sewage sludge, etc., as well as to cheaper primary fuels (for example heavy oil in combustion chambers) and thereby to the purchase and operation an extremely expensive exhaust gas afterburning system downstream of the tunnel furnace can be dispensed with, since the exhaust gas in the system according to the invention is already completely afterburned at high temperature in the combustion zone 4 and is derived directly from the high-temperature furnace gas suction channel 31. If secondary fuels are used, the mixing chamber 29 acts as a combustion chamber and the end end wall 28 forms a flame protection wall shielding the combustion chamber 29 against the combustion zone 4. An automatic ash discharge device 29 'is then provided below the combustion chamber 29.

The invention is not limited to the embodiment shown in the drawing, but can be modified in various ways. For example, it is also possible to provide more than six bogie car trains 6 lying next to one another. The tunnel kiln can also be designed as a through-tunnel kiln, which, however, has to accept some disadvantages compared to a reversing tunnel kiln 1. For example, loading and unloading stations must then be set up at both ends of the tunnel furnace, whereas at the formation of the tunnel kiln as a reverse tunnel kiln 1 significant investment cost savings are possible. In particular, there are advantages here due to the uncomplicated gas routing for the furnace gas circulation and the fresh air supply.

Furthermore, it would be conceivable not only to provide the kiln cars 8 with a single trimming disk wall 21; depending on the shape and the size of the moldings 10, two adjoining facing disk walls 21 could also be provided, nevertheless a good, naturally occurring heat transfer is ensured, especially with this variant for each facing disk wall 21 when passing through the tunnel furnace there is an opposing trimming disk wall 21 - with the exception of the bogie wagon trains adjacent to the tunnel side walls, which however are also exposed to heat radiation due to the stationary heat of the tunnel furnace side walls.

Claims

Claims:

1. A method for firing ceramic moldings (10, 10 '), in particular bricks, by guiding the moldings (10, 10') through a heating zone (3), a firing zone (4) and a cooling zone (5), the Shaped articles (10, 10 ') in the heating zone (3) opposite to shaped articles (10, 10') of a cooling zone (5) arranged parallel to the heating zone (3) and forming a common channel (2) with the heating zone (3) , characterized in that the molded articles (10, 10 ') are transported through the zones (3, 4, 5) stacked to form a plurality of narrow disk walls (21) parallel to one another, preferably each having a width corresponding to the length of a molded article , wherein one in one direction through the heating zone (3) and cooling zone (5) led trimming panel wall (21) closely adjacent to a trimming panel wall (21) guided in the opposite direction is moved with intensive radiation heat transfer.

2. The method according to claim 1, characterized in that trimming disk walls (21) are formed, the thickness of which corresponds at most to the largest dimension of a molding (10)

3. The method according to claim 1 or 2, characterized in that trimming disc walls (21) are formed, the ratio of thickness to height in a range between 1: 1 and 1: 6, preferably between 1: 1 and 1: 4.

4. The method according to one or more of claims 1 to 3, characterized in that the covering disc walls (21) through the heating zone (3) to the firing zone (4) along a first path (11) are moved in the firing zone (4th ) are converted to an adjacent web and are returned along the adjacent web (15) through the cooling zone (5) opposite to the direction in which the trimming panel walls (21) were passed through the heating zone (3).

5. The method according to one or more of claims 1 to 4, characterized in that between the heating zone (3) and the firing zone (4) or between the firing zone (4) and the cooling zone (5) furnace gas from both the heating zone (3rd ) and also extracted from the firing zone (4) and an initial area of the heating zone (3), etc. a warming zone (3 '), in turn is supplied.

6. The method according to claim 5, characterized in that the heating zone (3 ') supplied hot furnace gas with increasing length of this zone (3') is supplied in a decreasing amount.

7. The method according to claim 5 or 6, characterized in that fresh air is preheated in a manner known per se with the extracted furnace gas and the preheated fresh air is supplied to the combustion zone (4).

8. The method according to claim 7, characterized in that the preheated fresh air supplied to the combustion zone (4) with increasing length of the combustion zone (4) in increasing amount - u.zw. up to the reversal area (13) - is supplied.

9. The method according to one or more of claims 5 to 7, characterized in that for the firing of burned-out moldings (10) by the furnace gas preheated fresh air in a beginning of the heating zone (3) following the burnout zone (3 ") of the heating zone (3rd ) is added.

10. The method according to claim 9, characterized in that the preheated fresh air supplied to the burnout zone (3 ") with increasing length of the burnout zone (3") is supplied in smaller quantities.

11. The method according to one or more of claims 6 to 10, characterized in that at least one burner (30) of the combustion zone (4) is supplied by the furnace gas in a known manner preheated fresh air.

12. The method according to one or more of claims 6 to 11, characterized in that fresh air preheated by the furnace gas is fed to a drying oven (53).

13. The method according to one or more of claims 6 to 12, characterized in that extracted furnace gas is fed to the combustion zone (4), preferably via a mixing chamber (29) arranged in the reversing region (13) of the moldings (10).

14. The method according to one or more of claims 5 to 13, characterized in that extracted furnace gas is fed to a drying oven (53).

15. The method according to one or more of claims 1 to 14, characterized in that heavy oil or alternative fuels, such as sewage sludge, etc., are used as fuel.

16. Plant for carrying out the method according to one or more of claims 1 to 15, with a heating zone (3), a burning zone (4) and a cooling zone (5) having a tunnel oven (1) and with a plurality through the tunnel oven (1 ) Movable bogie car trains (6), each of which a bogie car train (6) can be moved in the opposite direction to an adjacent bogie car train (6), characterized in that bogie cars (8) forming a bogie car train (6) each for receiving a maximum of two side panel walls arranged side by side (21) are formed.

17. Plant according to claim 16, characterized in that the kiln car (8) are each only designed to receive a single trimming disk wall (21), the width of a kiln car (8) being only slightly wider than the maximum largest dimension of a molding (10).

18. Plant according to claim 16 or 17, characterized in that the tunnel furnace - as known per se - is designed as a reversing tunnel furnace (1), at one end an unloading and loading station (20) for the kiln cars (8) and at the other End of a kiln car transfer station (13) lying in the firing zone (4) for transferring the kiln car (8) to exit lanes (15) arranged parallel to entry lanes (11) for the kiln car.

19. Plant according to one or more of claims 16 to 18, characterized in that between the heating zone (3) and the firing zone (4) or between the firing zone (4) and the cooling zone (5) in a furnace gas suction channel (31) in the furnace interior (2) opens out, the first branch duct (33) leading to an initial area of the heating zone (3), etc. a warming-up zone (3 ') of the same, is guided and there it opens out via one or more orifices (34) distributed over the length of the warming-up zone (3'), and a second branch duct (37) which leads to an exhaust gas chimney (38) is has

20. Plant according to claim 19, characterized in that a third branch channel (41) of the furnace gas suction channel (31) in the combustion zone (4), preferably in one at the end (12) of the reversing tunnel furnace (1) arranged mixing chamber (29) Burning zone (4), opens out

21. Plant according to claim 19 or 20, characterized in that the furnace gas suction channel (31) is designed as a recuperator for a fresh air supply line (32) the fresh air supply line (32) is designed as a jacket channel surrounding the furnace gas suction channel (31)

22. Plant according to claim 21, characterized in that in the fresh air supply line

(32) the fresh air in a first recuperator in counterflow to that in the first branch duct

(33) guided furnace gas is fed and the preheated fresh air can be fed at least partially into a burnout zone (3 ") following the heating zone (3 ') of the heating zone (3) via branch lines (45).

23. System according to claim 21 or 22, characterized in that the fresh air supplied in the fresh air supply line (32) is guided in a second recuperator part in cocurrent to the furnace gas flowing in the second branch duct (37) and at least partly via branch lines (47) Firing zone (4) can be fed

24. Plant according to one or more of claims 21 to 23, characterized in that the Firschluftzufuhrleitung (32) with a branch line (49) opens into at least one burner (30)

25. Plant according to one or more of claims 21 to 24, characterized in that the fresh air supply line (32) opens into a drying oven (53)

26. Plant according to one or more of claims 21 to 25, characterized in that in the side walls of the tunnel furnace (1) in the heating zone (3) and in the cooling zone (5) hot air driving nozzles (54) are provided for supplying preheated fresh air.

27. Plant according to one or more of claims 16 to 26, characterized in that high pressure burners are provided in the side walls of the tunnel furnace (1) in the heating zone (3) and in the cooling zone (5) and optionally in the combustion zone (4).

28. Plant according to one or more of claims 16 to 27, characterized in that the kiln car (8) on in the interior (2) of the tunnel kiln (1) at the bottom (56) arranged rail tracks (7) by means of high-temperature-resistant rollers (55), which are arranged on the underside of a refractory bogie body (22) are guided.

29. Plant according to claim 28, characterized in that the bottom of the tunnel furnace (1) is formed by a sealing cover plate (56)

30. System according to claim 28 or 29, characterized in that on the bottom (56) of the tunnel furnace (1) between adjacent rail tracks (7) in the height of the bogie body (22) projecting web plates (57) which extend in the longitudinal direction of the rail tracks ( 7) extend, are provided.

31. Plant according to one or more of claims 28 to 30, characterized in that the rollers (55) from the kiln car body (22) down to just below the bottom (56) of the tunnel oven (1) protruding shielding plates (58) which extend lengthwise and extend transversely to the longitudinal direction of the rail tracks (7).

32. System according to one or more of claims 16 to 31, characterized in that the trimming disc walls (21) on chamotte cross-pull sole stones (24) can be supported.

33. Installation according to one or more of claims 16 to 32, characterized in that for the combustion of secondary fuel with an ash discharge device (29 ') provided combustion chamber (29) is provided which is shielded against the combustion zone (4) with a flame protection wall (28)