EP0440181A2 - Regenerative reactor for burning industrial effluent gases - Google Patents

Abstract

The invention relates to a regenerative reactor for burning industrial effluent gases, in particular outgoing air containing harmful substances, with a number of heat exchanging regions (1, 2, 3;70, 71) which are accommodated in a housing having a peripheral wall (11; 11') and which are arranged in each case adjacent to one another separated from one another by gastight partitions (13, 14, 15; 74) arranged on the peripheral wall. To reduce the forces acting on the peripheral wall (11, 11'), the partitions (13, 14, 15; 74) are provided with at least one expansion compensation zone (DA) and preferably designed in meandering form.

Description

The invention relates to a regenerative reactor for burning industrial exhaust gases, in particular exhaust air containing pollutants, according to the preamble of claim 1. Furthermore, the invention relates to a method for burning industrial exhaust gases according to the preamble of claim 16.

Various exhaust gases are generated in industry, which contain unburned hydrocarbons. For example, pentane is used in the foaming of plastics, which must be burned in a reactor of the type mentioned at the beginning. In the production of electronic circuit boards, too, a solvent-containing exhaust gas is produced after they have been painted. In addition, when smoking meat, exhaust air with organic hydrocarbons is created. When car bodies are dried in drying plants, solvent-containing exhaust air and exhaust gases are generated, which develop during the direct heating of the drying process. After all, considerable amounts of solvent-containing exhaust air are generated when printing presses are used, and exhaust gases are produced when industrial ceramics are dried.

There are various systems for the combustion of such exhaust gases, which work with regenerative reactors which have heat exchangers in order to keep the thermal efficiency high and, as far as possible, to reduce or avoid the supply of additional heat by means of a burner to a minimum.

Such a reactor system with three reactors in the form of so-called treatment towers is known from DE-OS 37 37 538. In their hottest area, namely in the area of their oxidation chambers, these towers are connected by a large-volume connecting line. Like the inner part of the system, this must be brought to the oxidation temperature when starting, which can be, for example, 800.degree. This requires considerable amounts of heat and long heating times.

A similarly constructed reactor system is known from DE-OS 38 37 989. No separate treatment towers are provided for this. Rather, three heat exchangers are arranged in a row next to one another within a housing. Here, too, there is a very large oxidation chamber, which at the same time also creates the connection between the heat exchangers. This oxidation chamber must first be heated when starting, which requires a lot of energy and long heating times. moreover, due to the high operating temperature, high heat losses occur.

Because of these technical conditions, these known reactors are practically only suitable for exhaust gas quantities from about 15,000 Nm³ / h.

Finally, from DE-OS 29 51 525 a method for the treatment of a gas for the removal of impurities is known, in which a reactor called a furnace is used, which has a cylindrical housing which has three heat exchanger regions which are sector-shaped in cross section. There is an oxidation chamber above the heat exchanger areas, in which the exhaust gases are burned. Due to the heat generated, the housing is subjected to high mechanical loads, which can lead to deformation or even destruction.

It is therefore an object of the invention to provide a thermally optimized reactor.

This object is achieved in a regenerative reactor of the type mentioned with the help of the features listed in claim 1. Because the partition walls are provided with an expansion compensation zone, the forces and stresses which occur when these walls are heated excessively and which act on the peripheral wall of the housing are greatly reduced. In this way, deformations of the housing that occur in the course of several operating cycles are reduced to a minimum.

A reactor is preferred in which the expansion compensation zone of the partitions extends over the entire wall Width extends and the partitions are corrugated. Partition walls designed in this way can absorb forces over their entire width and thus reduce stresses which occur when the reactor heats up excessively. The partitions are relatively simple and therefore inexpensive to manufacture.

Furthermore, an embodiment of the reactor is particularly preferred in which the partition walls are double-walled. Since the adjacent heat exchanger areas are exposed to different gas flows and thus have different temperatures, thermal stresses which are based on the sharp drop in temperature within the partition walls can be reduced. The double-walled walls isolate the individual heat exchanger areas better from each other, so that less thermal stresses can occur.

Furthermore, an embodiment of the reactor is preferred in which the partition walls starting from the peripheral wall meet at one point and are connected to a double-walled tube. This opens on the one hand in the oxidation chamber of the reactor and on the other hand outside the housing. It is therefore possible to extract hot gas from the oxidation chamber and thus optimally adjust the temperature of the reactor, in particular to avoid overheating. In this way, an excessive increase in temperature inside the reactor can be avoided. This can also cause thermal stress optimally dismantle. Because the tube in the interior of the reactor is double-walled, air, preferably cold air, can be supplied to the gas withdrawn from the oxidation chamber, so that the gas withdrawn from the reactor overall has a significantly lower temperature than in the oxidation chamber. This also makes it possible to further reduce thermal loads on the reactor and the downstream elements.

An exemplary embodiment of the reactor is particularly preferred, which is characterized in that a flap is arranged in the tube serving to draw off the gas and can be acted upon by the withdrawn gas and the cold air supplied. Due to the reduced gas temperature due to the supply of cold air, the thermal load on the flap decreases, which can then be carried out relatively easily.

Further embodiments of the reactor result from the remaining subclaims.

The object of the invention is also to provide a method for burning industrial exhaust gases, in particular pollutant-containing exhaust air, in which the thermal load on the reactor is minimized.

This object is achieved in a method of the type mentioned at the outset with the aid of the method steps listed in claim 16. By changing the flow directions of clean gas, raw gas and Purge gas within the heat exchanger areas, the temperature within the reactor can be adjusted. It is also avoided when switching the gas streams that raw gas is released into the environment.

A method is particularly preferred in which hot clean gas, hot gas, is withdrawn from the oxidation chamber when the temperature inside the reactor threatens to become too high. Fresh air, preferably cold air, is added to the hot gas to reduce the thermal load on downstream control means.

Figur 1A

und 1B eine Explosionsdarstellung eines ersten Ausführungsbeispiels des Reaktors, wobei in Figur 1A die Haube und in Figur 1B das Basisteil des Reaktors wiedergegeben sind;

Figur 2

eine Darstellung der Anschlüsse des Reaktors nach Figur 1A und 1B;

Figur 3

Tabellen mit zwei Versionen von im Betrieb des Reaktors nach den Figuren 1A, 1B und 2 gewählten Ventilstellungen;

Figur 4

eine schematische Darstellung eines zweiten Ausführungsbeispiels eines erfindungsgemäßen Reaktors;

Figur 5

eine Tabelle mit den beim Betrieb des Reaktors nach Figur 4 gewählten Ventilstellungen;

Figur 6

einen Schnitt entlang der Linie VI-VI in Figur 4;

Figur 7

einen Schnitt entlang der Linie VII-VII in Figur 6;

Figur 8

einen Schnitt längs der Ebene eines Trennblechs gemäß Figur 1A/1B im zusammengebauten Zustand des Reaktors;

Figur 9

eine Trennwand in Draufsicht mit einer U-förmigen Dehnungsausgleichszone;

Figur 10

eine Trennwand in Draufsicht mit einer S-förmigen Dehnungsausgleichszone;

Figur 11

eine Trennwand in Draufsicht mit einer durchgehenden mäanderförmigen Dehnungsausgleichszone;

Figur 12

eine Trennwand in Draufsicht mit einer Hinterschneidungen aufweisenden Dehnungsausgleichszone;

Figur 13

eine erste Ausführungsform des dem Abzug von Heißgas dienenden zentralen Rohrs im Reaktor und

Figur 14

eine zweite Ausführungsform des dem Abzug von Heißgas dienenden zentralen Rohrs im Reaktor.

The invention is explained in more detail below with reference to the figures. Show it:

Figure 1A

and FIG. 1B is an exploded view of a first exemplary embodiment of the reactor, the hood being shown in FIG. 1A and the base part of the reactor in FIG. 1B;

Figure 2

a representation of the connections of the reactor of Figure 1A and 1B;

Figure 3

Tables with two versions of valve positions selected in the operation of the reactor according to FIGS. 1A, 1B and 2;

Figure 4

a schematic representation of a second embodiment of a reactor according to the invention;

Figure 5

a table with the valve positions selected during operation of the reactor according to FIG. 4;

Figure 6

a section along the line VI-VI in Figure 4;

Figure 7

a section along the line VII-VII in Figure 6;

Figure 8

a section along the plane of a partition plate according to Figure 1A / 1B in the assembled state of the reactor;

Figure 9

a partition in plan view with a U-shaped expansion compensation zone;

Figure 10

a partition in plan view with an S-shaped expansion compensation zone;

Figure 11

a partition in plan view with a continuous meandering expansion compensation zone;

Figure 12

a partition in plan view with an undercut expansion compensation zone;

Figure 13

a first embodiment of the central tube for the extraction of hot gas in the reactor and

Figure 14

a second embodiment of the central tube for the extraction of hot gas in the reactor.

FIG. 1B shows the base part of a regenerative reactor 10 with a circular cylindrical peripheral wall 11. A tube 12 extends in its longitudinal axis and projects beyond the upper edge R 'of the peripheral wall 11. Between this tube 12 and the peripheral wall, three partitions 13, 14 and 15 are welded, which are arranged at equal angular intervals of 120 ° and have the same shape. If more than three partitions are provided, the angular distances should be selected accordingly.

The partitions are designed as rectangles, a cutout 13 ', 14' or 15 'being provided at the upper, inner corner facing the tube 12, which extends obliquely upwards and outwards from the upper end of the tube 12 , as can be seen from Figures 1B and 8. The boundary line of the section can, for example — as in FIG. 1B — run in the shape of a sector of a circle but also linearly.

The peripheral wall 11 is closed at the bottom by a bottom which seals the housing in a gastight manner. The partitions 13, 14 and 15 extend to this floor and are welded to it.

Through the three partitions 13, 14 and 15, which, starting from the peripheral wall 11, all in one Common point, here on the pipe 12, the interior of the housing is divided into three circular sector-shaped areas 1, 2 and 3, which are gas-tightly separated from one another by the partition walls, but in the upper area, namely in the area of the cutouts or cutouts 13 ', 14 'and 15' are connected.

In the floor 17, three connections are provided for each of the areas 1, 2 and 3, each of which has the index number of the area in question. Each of the areas in the floor 17 thus has a connection opening A for raw gas, which is consequently designated A1, A2 and A3. Likewise, each area 1, 2 and 3 has a connection opening R for clean gas, which is correspondingly designated R1, R2, for example R3. Finally, each of the areas 1, 2 and 3 has a connection opening S for purging gas, which is correspondingly designated S1, S2 and S3.

The connections for raw gas (A1 to A3), clean gas (R1 to R3) and purge gas (S1 to S3) can each be provided directly with a valve or slide, as is indicated in FIG. 2 by the oblique lines 25. Alternatively, such valves or slides can be located in the feed lines to these connections. Such valves are usually designed as flaps.

Above the base 17, an inflow chamber enclosed by the peripheral wall 11 is formed within the housing, which is separated into gas-tight inflow chambers by the three partition walls 13, 14 and 15 AK1, AK2 and AK3 is divided. The inflow chambers extend from the bottom 17 to a grate 30 approximately over a third of the height of the interior of the housing.

The grate 30, which can be designed as the grate 30 'shown in section in FIG. 4 and which is only indicated schematically in FIG. 1B, serves to support a bed 35 made of inert ceramic material with high heat storage capacity, which differs from the grate 30 extends almost to the upper edge R 'of the peripheral wall 11. The fill is indicated by cross hatching 36 in FIG. 1B. When the reactor is in operation, the temperature of the bed in the area of this cross-hatching decreases from top to bottom, for example a temperature of approximately 700 ° C. to 800 ° C. above and a temperature of approximately 100 ° C. below.

Approximately in the middle of the cross-hatched area 36 or somewhat below, an annular flange 40 is attached to the outside of the peripheral wall 11, which is provided with holes 41 in a conventional manner. This ring flange is therefore located in a medium temperature zone of, for example, 300 ° C. Depending on whether the flange is attached further up or down, the temperature prevailing there changes.

A ring flange 45 of a hood-shaped part is fastened to the ring flange 40, which is referred to below as hood 47 and is shown in FIG. 1A. This ring flange 45 also has holes 46, which can be brought into alignment with the holes 41 in the ring flange and serve to accommodate screws or other fastening means. With the help of these screws, not shown here, the hood can be attached to the housing.

The hood 47 has a cylindrical section 49 adjoining the ring flange 45, which is preferably made of steel and merges into a circular cover 50 at the top, which can also be made of steel and forms the upper end of the hood 47.

The embodiment of the reactor shown here is circular-cylindrical, that is to say that the housing, like the hood 47, has a circular-cylindrical shape. It is also conceivable that both parts are triangular, the triangular shape of the housing or the hood then being predetermined by triangular areas of the heat exchanger. Instead of the triangular shape, other polygonal outer shapes of the housing or the hood can also be selected.

For insulation and because of the high temperature inside, the hood 47 is continuously provided with a refractory lining, which is only indicated schematically here with the reference number 52. The material of the lining can be chosen arbitrarily. For example, a fireproof brick with lightweight bricks, with fireproof cement or with a fireproof mat made of silicates, for example, can be selected.

It can be seen from the illustration according to FIGS. 1A and 1B that the peripheral wall 11 and the partition walls 13, 14 and 15 do not have to be lined with fire-resistance. The use of high-alloy steel is sufficient here. The insulation in the upper, particularly hot region of the bed 35 is taken over by the refractory lining 52 of the hood 57.

The hood 47 has a lateral connection piece 55, through which hot gas can be removed, for example for heating water, if necessary, for example if the heat generated during the combustion of the raw gas is too high. Likewise, hot gas can also be withdrawn through the central tube 12, which results in a particularly compact construction of the reactor.

Furthermore, a burner 56 is provided on the hood 47, which can be arranged in the cover 50, or as shown here, in the side wall of the hood. The flame of the burner is directed towards the center of the space enclosed by the hood 47.

The inside diameter of the hood 47 is dimensioned such that only a small gap 51 (see FIG. 8) remains between its inside and the radial outside 13 ″, 14 ″ and 15 ″ of the partitions 13, 14 and 15. The height of the hood 47 is dimensioned such that only a small gap 53 (see FIG. 8) remains between its inside in the area of the cover 50 and the upper edge 13 ″ ″, 14 ″ ″ and 15 ″ ″ of the partition walls.

With the hood 47 in place, an oxidation chamber 60 of the reactor 10 is formed between its inner wall and the top of the bed 35, in which the main oxidation of the raw gas supplied takes place.

When industrial exhaust gases or exhaust air containing pollutants are burned, raw gas, clean gas and purge gas are alternately routed through the various heat exchanger areas. For example, the raw gas is fed through the bed 35 in the heat exchanger area 1 of the oxidation chamber 60 and burned there. The resulting clean gas is discharged through the bed 35 in the heat exchanger area 2. The gas in the oxidation chamber 60 must flow from the oxidation chamber area O1 above the heat exchanger area 1 through the recesses 13 ', 14' and 15 'of the partition walls 13, 14 and 15. There is an intensive swirling. This area of the cutouts in the partition walls is therefore also called the swirl area VW. In particular in the start-up phase, that is to say when the reactor is started up, the air in the swirl region VW is heated by the burner 56 and brought to the reaction temperature. The burner must also be switched on if the heat released during the combustion of the exhaust gases is not sufficient to maintain the reaction temperature.

The gas flow is adjusted by adjusting the slide or flaps, the connections for raw gas (A1 to A3), clean gas (R1 to R3) and purge gas (S1 to S3) are assigned. It does not matter through which heat exchanger area the raw gas is supplied and through which the clean gas is discharged. Due to the symmetry of the arrangement, the same relationships always result.

The method for burning industrial exhaust gases and the function of the reactor are explained in more detail with reference to FIGS. 2 and 3. By opening and closing the corresponding valves or flaps assigned to the connections A1 to A3, R1 to R3 and S1 to S3 in the bottom 17 of the housing of the reactor 10, the gas flows are cyclically switched on in order to achieve a recovery of the heat generated during the combustion of the gases.

FIG. 2 schematically shows the pipelines connected to the reactor 10 and the associated valves or flaps.

The raw gas is supplied to the connections A1, A2 and A3 and the valves arranged there to the reactor via a line 62, into which a blower 63 or some other air delivery device can optionally be connected. The clean gas can be drawn off or sucked from the connections R1, R2 and R3 into a line 65 by a blower 64 or another air delivery device and fed via a line 66, for example to a chimney, or via a line 20 and a line 67 as purge gas to the connections S1 up to S3. By dashed lines of the blower 63 is intended to indicate that one of the blowers can also be omitted.

A dashed line in FIG. 2 indicates that air or cold air can also be used as a purge gas via a line 21.

There are two possibilities for the operation of the reactor 10, namely version 1 and version 2, which are explained using the tables in FIG. 3. The gas flows through the heat exchanger areas of the reactor 10 are set by opening and closing the valves or flaps assigned to the connecting pieces in the bottom 17. In Figure 3, only the opened connections, that is, the connections whose associated flaps or valves are open, are shown. The other connections, not specified, are closed without this being specifically mentioned in FIG. 3.

The heat exchanger regions of the reactor 10 are identified by the numbers 1, 2 and 3. An upward-pointing arrow indicates that the temperature of the bed 35 of the relevant heat exchanger area is increasing, while a downward-pointing arrow means that the temperature of the relevant bed 35 of this area is decreasing.

A horizontal line indicates that the temperature of the bed remains essentially unchanged.

In version 1 of the method, the connections A1, R2 and S3 are initially opened in phase I, so that raw gas is fed via the bed 35 in the heat exchanger area 1 to the oxidation chamber 60 and is oxidized there. This process is exothermic, which means that heat is released. The resulting hot gas is discharged as clean gas via the bed 35 in the heat exchanger area 2. During this time, the bed 35 in the heat exchanger area 3 is flushed with purging gas.

With such gas routing, the temperature in the heat exchanger area 2 increases while it decreases in the heat exchanger area 1. There is no significant temperature change in the heat exchanger area 3 due to the flushing, which takes only a short time.

In the exemplary embodiment of the reactor shown here or in the embodiment of the method, for example, after 3 minutes it is switched to phase II and after another 3 minutes to phase III. After this, after another 3 minutes, the system switches back to phase I.

In this way, the heat exchanger area heated by the clean gas is used for heating the raw gas supplied, which may be present there can also ignite and thus be oxidized.

Version 2 of the method shown in FIG. 3 is more effective, but involves a higher switching effort: Rinsing phases IIa, IIIa and Ia, which for example each lie between phases Ib, IIb and IIIb, which last, for example, 2 to 3 minutes Last 10 seconds, and during which raw gas is flushed from a heat exchanger area into the oxidation chamber and burned there.

In version 2 in FIG. 3, too, only open connections are specified; the connections closed during an operating phase are not shown in each case.

According to FIG. 3, the connections A1, R2 and R3 are opened in version 2 during phase Ib, so that raw gas is supplied to the oxidation chamber 60 via the heat exchanger area 1, oxidized there and then discharged again via the two heat exchanger areas 2 and 3 connected in parallel . The latter are heated up while the heat exchanger area 1 releases heat to the raw gas and thereby becomes colder. Subsequently, the heat exchanger area 1 is briefly flushed during phase IIa in order to burn the raw gas still contained in it in the oxidation chamber 60. The raw gas is otherwise supplied to the oxidation chamber 60 through the heat exchanger area 2 during phase IIa and derived from there as clean gas via the heat exchanger area 3.

After purging, the clean gas is then additionally discharged via the -purged- heat exchanger area 1 in phase IIb. The further process of the cyclical interchange is shown in FIG. 3, version 2. That is, the supply and discharge of raw and clean gas or of purge gas is continued, as just described, in each case in the subsequent heat exchanger area.

Figure 4 shows very schematically a simplified system with only two heat exchanger areas 70 and 71, in which there is also a bed 35 of heat exchanger material. The heat exchanger regions 70 and 71 each have a semicircular cross section here, which results from FIG. 6. The beds 35 lie on a grate 30 ', to which an inflow chamber or an inflow box 72 or 73 adjoins at the bottom. The connections of the inflow box 72 are designated A1, S1 and R1, those of the connection box 73 with A2, S2 and R3, the connection openings A being determined for raw gas, the connection openings R for clean gas and the connection openings S for purge gas.

The partition between the two heat exchanger areas 70 and 71 and the two inflow boxes 72 and 73 is designated 74. It has a flow opening 75 at the top in the oxidation chamber 76, which is shown in FIG. 7 and essentially here is rectangular. A gas stream 77 can flow through this opening from left to right or a gas stream 78 from right to left, which is indicated in FIG. 4 by corresponding arrows.

The flame of an ignitable burner 56 'is directed at the flow opening 75.

A line 80 is laterally connected to the oxidation chamber 76, in which a valve B designed as a flap is arranged. Line 80 is required for the rinsing processes which take place during phases Ib and IIb according to FIG. The feed line for raw gas is designated in FIG. 4 with 82, the discharge line for clean gas with 83. It usually leads to a chimney, not shown here. The feed line for purge gas is designated 84.

The reactor 85 shown in FIG. 4 can be constructed similarly to the reactor 10 according to FIGS. 1A and 1B. In particular, a hood with refractory lining can also be provided here, which can also be welded to the peripheral wall 11 '. However, the hood is not shown in FIGS. 4 to 7, since these figures only show a schematic representation.

The gas flow 77 in the oxidation chamber 76 indicated by an arrow arises in phase Ia, that is to say when the connections A1 and R2 are open are. For example, these remain open for 3 minutes.

Subsequently, in phase Ib, the heat exchanger area 70 is flushed by opening the connection S1, the flushed gas after combustion in the oxidation chamber 76 being fed directly to the chimney via the line 80 and the valve B.

After purging, the system switches to phase IIa, the gas stream 78 indicated by an arrow being formed while the connections A2 and R1 are open. It is then rinsed in accordance with phase IIb. Afterwards, phase Ia is started again.

The control of the gas flow results from the table according to FIG. 5, in which the connections opened in the individual phases Ia, Ib, and IIa and IIb are specified. Here, too, as in FIG. 3, closed connections are not specified.

Similar to FIG. 2, FIG. 4 provides blowers 63 'and 64' which push or suck the gas flows through the reactor 85.

In Figures 1, 2, 6, 7 and 8, the expansion compensation zones in the partition walls between the heat exchanger areas are only indicated and marked with DA. 9 to 12, their design will be explained in more detail below.

FIG. 6 shows a top view of the reactor 85 shown in FIG. 4, the cover being removed.

In this illustration, the peripheral wall 11 ', the burner 56' mounted in the hood of the reactor 85, the partition 74 provided with expansion compensation zones DA between the heat exchanger regions 70 and 71 and the throughflow opening 75 provided in this partition, which here forms the swirl region, can be seen. The line 80, in which a valve B is located, is connected laterally to the oxidation chamber 76.

FIG. 7 shows a cut-open reactor 85, as shown in FIGS. 4 and 6.

In this figure, the partition 74 can be seen from the side, so that its flow opening 75 is clearly visible. Through this one can see the opening of the burner 76, which is directed towards the throughflow opening or the swirl region of the reactor 85. The two regions of the oxidation chamber 76 which are separated from one another by the partition 74 are connected to one another via the flow opening 75.

In FIG. 7, the surrounding wall 11 ', the heat exchanger region 70 and the bed 35 thereof can also be seen.

Figure 8 shows a partial section through a reactor 10, as shown in Figures 1A and 1B. However, in this drawing, the hood 47 is placed on the housing of the reactor 10 formed by the surrounding wall 11. In Figure 8 is the central tube 12 can be seen, to which the partitions 13, 14 and 15, here the partition 14, are welded. The other side of the partition walls is welded to the surrounding wall 11. In this illustration it can be seen that the partitions are essentially rectangular, a recess 14 'being provided at their inner upper corner, which here has an arcuate boundary line.

The upper edge R 'of the housing or the surrounding wall 11 is shown in broken lines here. The bed 35 of the heat exchanger region 2 is highlighted by hatching.

The hood 47 rests with its flange 45 on the flange 40 attached to the surrounding wall 11 and is fastened in a suitable manner, for example by screws. The wall of the hood has a refractory lining 52.

The inner dimensions of the hood 47 are matched to the dimensions of the partition walls or the peripheral wall 11 in such a way that a gap 51 between the radial outer edge 14 ″ of the partition wall 14 and between the upper edge 14 ″ ″ of the partition wall 14 and the cover 50 of the hood 47 a gap 53 remains.

The free space above the bed 35 is divided by the partitions 13, 14 and 15 into three areas which are connected to one another due to the cutouts 13 ', 14' and 15 '. wherein the gas flows in the area of the recesses can pass from one heat exchanger area to the other. A swirling of the gases occurs, so that this transition area is referred to as swirling area VW.

In this illustration, the expansion compensation zone DA of the partition 14 is only indicated. Their more precise configuration is explained in more detail with reference to FIGS. 9 to 12.

FIG. 9 shows any partition shown in the figures mentioned, which - seen from above - has an expansion compensation zone DA, which is U-shaped here.

According to FIG. 10, an exemplary embodiment of a partition wall is shown which, seen from above or shown in section, has an expansion compensation zone DA which is essentially S-shaped.

According to FIG. 11, the expansion compensation zone of one of the partition walls shown in the figures extends over its entire length, the expansion compensation zone being meandering. The shape of the individual meanders is of secondary importance for the function of the expansion compensation zone. The individual arches of the meanders can thus be designed in the form of a circular arc or have any curvature. The individual meanders can also be rectangular, trapezoidal or triangular.

Another variant of the design of the expansion compensation zone is shown in FIG. Here the partition is provided with several undercut areas.

The expansion compensation zone DA of the partition walls shown in FIGS. 9 to 12 has the function of intercepting an expansion of the partition wall based on the temperature increase. The partitions are fastened on the one hand to the peripheral wall and on the other hand to the central tube inside the reactor or, as shown in FIG. 6-, in the form of a continuous partition. Also in the continuous partition of this embodiment there is an expansion or elongation of the partition based on the temperature increase, which is compensated for by the expansion compensation zone DA.

In the U-shaped configuration of the expansion compensation zone according to FIG. 9, when the partition walls are heated, the U-shaped arc of the partition wall is compressed, that is to say its width extension is intercepted. The same applies to the S-shaped configuration of the expansion compensation zone according to FIG. 10 and in particular to the meandering design of the expansion compensation zone DA according to FIGS. 11 and 12. The partition shown there is quasi a corrugated sheet so that expansions based on temperature increases can be optimally absorbed .

While in conventional reactors the housing is expanded particularly strongly in the area of the heat exchanger areas of the highest temperature, so that the peripheral wall is virtually bulged, the outer shape of the reactor remains practically unchanged due to the expansion compensation zones DA, as are provided here in the reactors according to the invention. A change in shape of the housing will usually not be reversible even after the housing has cooled, since the bed collapses when the housing is widened and the volume increases, thereby filling the resulting cavity. When the housing is subsequently cooled, high tensile forces arise in the partition walls, which endanger the weld seams on the peripheral wall and at the common location or on the central tube 12. This phenomenon is thus avoided by the expansion compensation zones, so that thermal stabilization of the reactor is ensured here.

FIG. 13 shows - greatly simplified - the central tube 12, for example of the reactor shown in FIG. 1B. The tube is double-walled here, that is, a further tube 12a is arranged inside the tube 12. Both tubes end here at the same height at the lower edge of the recesses 13 ', 14' and 15 'of the partition walls 13, 14 and 15. In FIG. 12 the partition wall 15 is shown as an example on the left.

According to FIG. 13, the inner tube 12a extends concentrically to the outer tube 12 over a region. Both pipes penetrate the grate 30 on which the bed 35 of the heat exchanger areas 1 to 3 rests. They also run concentrically to one another when they pass through the bottom 17 of the housing. The inner tube 12a then describes an arc and passes through the wall of the outer tube 12.

Below the exit point of the inner tube 12a, the outer tube 12 has a valve or a flap K1. A valve or a flap K2 is likewise provided in the tube 12a emerging from the outer tube 12.

If necessary, cold air is blown into the inner tube 12a, controlled by the flap K2, which can escape through openings provided in the wall of the tube 12a, which are indicated here by small arrows.

In FIG. 14, identical parts are provided with the same reference symbols. There, in turn, a schematic section through the reactor 10 is shown in FIG. 1B. An inner tube 12'a, which has openings indicated by arrows in its outer wall, in turn runs within the central tube 12 '. Both tubes run concentrically through the grate 30 and the bottom 17 of the housing of the reactor 10. Thereafter, the outer tube 12 'continues under an arc to a connection arranged at right angles to the tube 12', in which a flap K2 is arranged. The inner tube 12'a pierces the wall of the tube 12 'in the area of the bend. Below a flap K1 is arranged in the inner tube 12'a at this breakthrough point.

If necessary, hot clean gas can be sucked out of the swirling area VW of the oxidation chamber through the tube 12 (FIG. 13) or 12 '(FIG. 14). Hot clean gas is drawn off in particular when the temperature inside the reactor becomes too high, for example with a high solvent load on the raw gas. The control of the withdrawn hot gas takes place via the flap K1 in FIGS. 12 and 13. The temperature of the withdrawn hot gas is particularly high because the gas is withdrawn directly from the reaction zone. The flap K1 which controls the hot gas flow is therefore particularly exposed to heat and must be made of high-quality materials.

The central tube of the reactor is therefore preferably of double-walled design, that is to say a central tube 12a is arranged inside the tube 12 in FIG. 13, through which cold air can be blown in, controlled by the flap K2. This flows not only through the indicated openings but also from the top of the central tube 12a and is sucked with the hot gas into the annular space of the tube 12 surrounding the inner tube 12a as soon as hot gas is pulled out of the oxidation chamber after the flap K1 has been opened. The cold air supplied results in a gas mixture whose temperature is significantly reduced, for example by 300 ° C., compared to the hot gas present in the oxidation chamber. The one controlling the hot gas flow Flap K1 can therefore be built less complex and is therefore cheaper to manufacture. Overall, the thermal load on this area of the reactor is reduced.

The same applies to FIG. 14. There the hot gas is drawn off through the central tube 12'a. This hot gas is controlled by the flap K1, which must be correspondingly temperature-resistant if it is acted upon directly by the hot or clean gas originating from the oxidation chamber.

The fact that the pipe which carries the hot gas, that is to say the central pipe 12'a, is surrounded by the outer pipe 12 ', into which cold air is introduced via the flap K2, a reduction in the temperature due to the mixture of hot gas and cold air the flap K1 striking gas instead. Here, too, the temperature of the hot gas can be reduced from, for example, 800 ° C. to, for example, 500 ° C. and less. As a result, the thermal load on the reactor can also be greatly reduced here, that is, a cheaper flap can be used.

From what has been said above, it is clear that a relatively simple possibility of influencing the temperature in the oxidation chamber was created by withdrawing the hot gas. It is ultimately irrelevant to the process how the hot gas is drawn off. In particular, it is possible to dispense with the central tube of the reactor if the individual partitions are brought together so that a central free space remains through which the hot gas can then be drawn off. The type of attachment of the partition walls to a central tube is also irrelevant for the function of the temperature setting. Any connection between the pipe and the partition walls can therefore be provided, provided sufficient temperature resistance is guaranteed.

Overall, it is possible to house the heat exchanger and the oxidation chamber in a round cylindrical housing, which is arranged upright. The oxidation chamber is located at the upper end of this housing, the heat exchangers in the middle and the flow chambers for the heat exchangers below. The resulting reactor is therefore very compact and can be heated up quickly and inexpensively. On the other hand, the thermal loads occurring in this spatial design are reduced to a great extent by the measures described here, that is to say by the expansion compensation zones of the partition walls, by the possibility of extracting hot gas from the oxidation chamber and by the admixture of cold air.

The cylindrical housing is divided into sectors internally by the partitions. The partitions are gas-tight and generally prevent direct gas transfer between the heat exchanger areas.

The upper end of the cylindrical housing forms the "hot end", that is, the oxidation chamber. This is sealed off from the atmosphere by the hood 47, which can be screwed or welded to the cylindrical housing. All that is required here is a hood, which is put over the housing and radially isolating it in its hot areas by overlapping wall areas. The connection point between the hood and the housing, for example the flange 40 or 45 in FIGS. 1A and 1B, can be arranged such that the temperature of the wall area of the reactor is relatively low here. This means that the flange is placed approximately in the middle or somewhat below the center of the bed area 36. Therefore, the connection point is thermally relatively little stressed and can absorb the weight of the hood better, because it has a higher strength due to the lower temperature.

In the reactor described here, the heat exchangers consist of ceramic bulk material 35 which is heaped up on a sieve plate or a supporting grate 30, 30 '. Alternatively, metal honeycombs could also be used.

The dividing walls 13 to 15 are drawn into the hood 47 via the upper edge of the heat exchanger bed in order to achieve the residence time of the hot gases in the oxidation chamber 60 or 76 which is required for the complete combustion of the substances polluting the raw gas. The higher the intermediate walls are in the area of the oxidation chamber, in particular in the area of the lowest point of the recesses 13 ', 14' and 15 ', the longer the gas stays inside the oxidation chamber. The transition from one area of the heat exchanger to the other takes place via the cutouts or the swirl area VW. The cutouts result in a constriction of the flow, an increase in the speed of the gas flow and subsequently good mixing due to turbulence.

The burner 56 in the hood is arranged in such a way that the flue gas is added to the hot gas in the oxidation chamber precisely where there is a high level of turbulence and thorough mixing with the hot gas through the cutouts. Due to the symmetrical shape, when overflowing from each individual heat exchanger area to the other, the same conditions of overflow and admixing of burner flue gas can be achieved, that is to say also when the raw gas is oxidized.

When choosing a cylindrical housing, a particularly pressure-resistant design of the reactor is possible, which thus can withstand higher internal pressure values than, for example, square reactors.

The heat losses of the reactor are low because the circular cylindrical design has a small surface area compared to the volume. The height of the reactor is therefore preferably chosen to be approximately equal to its diameter. The partitions 13, 14, 15 and 74 do not necessarily need to be insulated, since the heat they transfer represents a further heat recovery.

The peripheral wall 11, 11 'does not have to be bricked up, since its material has no supporting function in the hot area. The hood 47 can be made fireproof on the inside or insulated on the outside. Their rotationally symmetrical shape according to the figures shown here can be produced particularly inexpensively.

The masses to be warmed up when starting up are low, since the masses of steel, brick lining and bulk material are small and there are no dead space volumes or dead space masses. Therefore, the heating energy is low and the heating time is short.

The hood 47 can also have an upward-facing cavity in the area of the cutouts 13 ', 14' and 15 'or in the swirl area VW, which can also be selected to be large enough that the cutouts in the partition walls can be dispensed with. The swirling of the overflowing gases takes place entirely in the bulge of the cover of the hood when the cutouts are omitted. The central tube 12 then opens into this swirling area formed in the hood.

The lower end of the cylindrical housing is the "cold end", which acts as the flow chamber for the Heat exchanger areas can be formed (compare 72 and 73 in Figure 4 and AK1 to AK3 in Figure 1B). Other inflow areas are also possible. The flow chambers have the connections A1 to A3, R1 to R3 and S1 to S3 for raw gas, clean gas and purge gas. Here valves or flaps are provided for the individual connections.

To regulate the autothermal operation, in which heat is generated in the oxidation chamber when the gases are being cleaned, hot gas can be removed via the pipe 12 or the connection 55. The removal is controlled by a hot gas flap 90 (FIGS. 1B and 2) or K1 (FIGS. 13 and 14), which is preferably arranged in the “cold area” or is installed in the connection 55. The gases are drawn through the reactor by means of a blower 64 or pushed through by means of a blower 63. In the former case, the hot air line 12, 55, 80 opens into the clean gas line at the intake port of the blower 64, in the latter case in the clean gas to be removed, that is to say in the gas stream supplied to the chimney.

The same design of the reactor can be used for operation with a catalyst. The bulk material 35 is then partially or completely replaced by catalyst bulk material or by a honeycomb catalyst. The reactor then works as a catalytic combustion reactor and is very versatile. The oxidation zone is wholly or partially in the heat exchanger area shifted. Since the operating temperature is lower during catalytic converter operation, appropriate design modifications can be made, for example, other materials can be used, or the wall thicknesses of the reactor can be reduced in part.

The reactor described here is very compact and can therefore be transported as a whole. This shortens the installation time at the place of use.

Claims (17)

Regenerative reactor for burning industrial exhaust gases, in particular exhaust air containing pollutants, with a plurality of heat exchanger regions (1, 2, 3, 70, 71) accommodated in a housing having a peripheral wall (11, 11 '), the partition walls attached to the peripheral wall by gas tightness (13, 14, 15; 74) are arranged separately from one another, characterized in that the partition walls (13, 14, 15; 74) with at least one expansion compensation zone for reducing the forces acting on the peripheral wall (11; 11 ') (DA) are provided. Reactor according to claim 1, characterized in that the expansion compensation zone (DA) has at least one section which is U-shaped, S-shaped or meandering in section and / or is provided with undercuts. Reactor according to claim 1 or 2, characterized in that the expansion compensation zone (DA) extends over the entire width of the partition (1,2,3; 74). Reactor according to one of the preceding claims, characterized in that the partition walls (1, 2, 3; 74) are corrugated. Reactor according to one of the preceding claims, characterized in that the partition walls (1,2,3; 74) are double-walled. Reactor according to one of the preceding claims, characterized in that the housing is polygonal or cylindrical, and that the partitions (1, 2, 3), starting from the peripheral wall, all meet essentially at one point (12). Reactor according to one of the preceding claims, characterized in that the partition walls (1, 2, 3) are attached to a common tube (12) which preferably opens into the oxidation chamber (60) and out of the housing in the region of a base (17) exit. Reactor according to one of the preceding claims, characterized in that the tube (12) is double-walled. Reactor according to one of the preceding claims, characterized in that the double-walled tube has an inner and an outer tube (12a, 12; 12'a, 12 '), one of which is the withdrawal of gas from the Oxidation chamber (60) and the other of the supply of air, preferably cold air, is used. Reactor according to one of the preceding claims, characterized in that a flap (K1) is arranged in the tube (12; 12 ') serving to draw off the gas from the oxidation chamber and can be acted upon by a mixture of the extracted gas and the supplied air . Reactor according to one of the preceding claims, characterized in that the partition walls (13, 14, 15; 74) pass through the housing essentially over their entire length, so that on one side of the heat exchanger regions (1, 2, 3; 70, 71) separate inflow chambers (AK1, AK2, AK3; 72.73) are formed and, on the other side, oxidation regions (01, 02.03) assigned to a heat exchanger region are formed, which are connected via a swirl region (VW; 75) common to all oxidation regions. Reactor according to one of the preceding claims, characterized in that the housing has a cover (47) which closes off the oxidation chamber and which at least partially covers the peripheral wall (11) and is preferably provided on its inside with a fire-resistant coating (52). Reactor according to one of the preceding claims, characterized in that connections for raw gas (A1, A2, A3), clean gas (R1, R2, R3) and purge gas (S1, S2, S3) open into the inflow chambers (AK1, AK2, AK3) and are preferably arranged in the end of the housing opposite the oxidation chamber and are each assigned to a heat exchanger area (1, 2, 3; 72, 73). Reactor according to one of the preceding claims, characterized in that a burner (56; 56 ') which heats up at least the oxidation chamber (60; 76) is provided. Reactor according to one of the preceding claims, characterized in that the heat exchanger material (35) can be replaced in whole or in part by catalyst material. Method for burning industrial exhaust gases, in particular of polluted exhaust air, in particular with the aid of a regenerative reactor according to one of claims 1 to 15, in which clean gas, raw gas and purge gas are passed alternately through the heat exchanger areas in order, on the one hand, to heat the clean gas into the heat exchanger areas to transfer, on the other hand, the heat from the heat exchanger areas in the raw gas and finally to purge raw gas from the heat exchanger areas, characterized in that fresh air is used as the purge gas. A method according to claim 16, characterized in that hot gas is withdrawn from the oxidation chamber and that fresh air, preferably cold air, is fed to it.

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