DE3446342A1 - Device for the catalytic combustion, in particular afterburning, of gases, exhaust gases, flue gases or similar combustible substances - Google Patents

Abstract

A device for the catalytic combustion or afterburning of gases includes a support structure and a catalyst applied to this. The device is arranged in the flow path (A) of the gases, for example a flue gas offtake (O). The support structure includes at least one base part (1, 1a, 1b, 1c) having support elements (2) extending into the flow path of the gases. In order to avoid the risk of blockages as a result of flake formation or deposits of solids contained in the gases and to achieve a high catalytic efficiency and simple construction, the support elements are designed as catalyst surfaces (21) directed transversely to the gas flow and extend like rays into the flow path. In order to achieve a further temperature increase, in particular when there is a risk of undershooting certain minimum heat values for afterburning, wires (5) running in the flow direction and made of highly heat-conducting material are embedded into the support structure and likewise extend into the flow path. <IMAGE>

Description

Device for catalytic combustion, in particular afterburning of gases, exhaust gases, flue gases or the like D5 flammable substances

The invention relates to a device for catalytic Burning, especially after-burning of lawns, exhaust gases, ID smoke gases or similar flammable substances with a Support structure (substrate) and one attached to it Catalyst, the device being arranged in the flow path of the combustible substances.

Known devices of this type are designed as catalytic afterburner in the form of a honeycomb ceramic, which is coated with a noble metal catalyst. They are in the flue of stoves for rush, liquid or solid fuels are built in and are used for the afterburning of pollutants that are due in the furnace incomplete combustion are not burned and are deposited either in the chimney as creosote or in the Environment. With these honeycomb afterburners are the noble metal catalyst, normally platinum-bearing surfaces in the direction of the flow of the afterburning Substances arranged. In order to obtain a sufficiently large contact area for the catalysis process, must the honeycombs can be arranged relatively close to one another. So they form in the direction of flow, behaving

3Π moderately narrow channels due to flake formation and deposits of other solid matter contained in the exhaust gases are easily clogged. In order to guarantee the functionality of the flue gas duct anyway and to avoid that there is accumulation of flue gas underneath the catalytic converter with all associated driving (Flue gas explosions etc.) must occur during such events a by-pass should be provided, which, if the value is exceeded certain marginal pressures come into function and the space

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Short-circuit below the catalytic converter with the chimney. This undermines the catalytic function. aside from that these known honeycomb-shaped ceramics are in one piece formed and thus run the risk that with unilateral D5 Wärmebeaufschlagunq heat stresses arise that at least partial destruction (parts blown off from the sewers).

In contrast, the invention. 1 is based on the object

to create a facility of the type described above, where there is a risk of clogging due to flocculation or deposition of other solids is excluded and a high catalytic efficiency guaranteed.

This object is achieved according to the invention in that the device has at least one base part with it carried support elements extending into the flow path comprises the catalyst surfaces directed transversely to the flow form. A device is thus proposed which allows the formation of much wider channels than the known afterburning device, but at the same time through the arrangement of the catalyst surfaces at right angles to the direction of flow a sufficient flushing around this Surfaces and thus sufficient catalytic contact between the flammable substance and the catalyst layer. Such components are relatively inexpensive manufacturable and, as also from the following explanations emerges, with training of the most varied of sizes easy to manufacture and offer as retrofit parts for existing furnaces.

It is particularly advantageous if the device has a plurality of positively and / or non-positively joined together Includes base parts, of which the carrier elements with their catalyst surfaces radiate into the flow

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■ w e q extend. Such a facility can after simple principle of a modular system can be provided and assembled. In the event of any damage it is easy and inexpensive to replace individual parts

Π5 without the need to replace the entire device requirement. Furthermore, with the help of this basic structure, catalytic converters of the most varied of pipe lengths can be manufactured put together for different throughputs. In other words it will be the number of for use required individual components determined by the required performance.

In a preferred embodiment of the invention, the base parts can be designed as cylindrical rings, from which the carrier elements radiate outwards extend. In other words, when several such components are put together, the base parts form a kind of "spine", of which the support elements extend outwards in the manner of spokes or ribs. Such components are easy and inexpensive to manufacture, to keep in stock, to transport and to install. Self with only one-sided heating, there are no significant thermal stresses in the respective component.

According to another expedient embodiment, can the base parts are designed as segments of a hollow body jacket, from which the carrier elements radiate out extend inward. In this case, several such base parts are joined together to form a ring, and it several rings in a row, in the direction of the flow path seen to be arranged next to each other. The conditions with regard to low thermal stresses are the same as in the embodiment described above, closed cylindrical rings with outwardly towards beam elements extending in the form of rays

In the case of both expedient embodiments, a number of the base parts can preferably be combined in such a way that the carrier elements of base parts which are adjacent in the direction of flow are offset from one another. This allows the direction of flow of the gas to be post-combusted in relation to the catalyst surfaces to be flown to be influenced in such a way that the gas is given a certain twist, which leads to turbulence and thus to an even more intimate wash around the carrier elements. With a suitable design, a helical flow extending over the entire length of the device can be established, although it is of course also possible to achieve any other type of desired flow by appropriately displacing the carrier elements with respect to one another.

About the ratio of the required catalyst areas to optimize the passage cross section for the gas as possible, the support elements are advantageous as elongated flattened rods, spokes, slats, fingers, wings or the like. formed that have an oval or can otherwise have an aerodynamically favorable cross-section. For similar reasons, the carrier elements with their Catalyst surfaces inclined to the flow on the grass parts be arranged.

For smaller catalytic converter devices, it is advantageous to design the carrier elements integrally with the base parts, because this means that components in reasonable dimensions

3Πsions in terms of manufacture, transport and storage result. Such elements are particularly suitable for smaller heating systems such as domestic fireplaces. For larger systems, on the other hand, it is just as possible Provide support elements that υß by Formschi with the Base parts are connectable. A mnntaqe of such parts can be easily performed on the spot.

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With regard to installation and simple storage, it is particularly useful if the base parts with the carrier elements surrounded by a multi-part housing shell

Π5 and held, which is essentially in the direction of of the flow path extends. Such an arrangement is also favorable with regard to thermal expansion, among other things the sheath the parts in a substantially form-fitting manner their location holds and this still has enough options

Have ID to move sideways. The shell parts themselves can advantageously be held together in a non-positive manner, for example with the help of tension rings made of heat-resistant material.

To the staggered arrangement in a particularly simple way of adjacent support elements in the direction of flow and thus an intentional specific conduction of the exhaust gas flow to ensure that this arrangement can be easily adjusted at the same time, in flow direction Adjacent grass parts with means for gradually adjusting the angular position of the respective carrier elements be provided to each other. Such adjustment means can be used in expediently as positive locking elements in the form of balls, pins, knobs or the like. with corresponding Be provided counter bearings. These Geqenlager are to be provided at predetermined angular intervals so that each desired angle changes can be easily adjusted without any changes afterwards during operation of these positions. In the case of smaller diameters, such locking elements can be used approximately every lfio, at larger diameters even up to Io can be provided. The adjustment causes a change in resistance in the flow, and this changes the conditions with regard to the areas around which the air flows, which also leads to a change in the catalytic combustion.

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. In a preferred manner, the base parts and the support elements exist, but also the parts of the housing shell made of heat-resistant material such as ceramic or similar fired Earth. As is already known from the prior art, this material also acts as a catalyst Precious metal coatings serve particularly favorable catalyst properties on.

In order to avoid temperature fluctuations that lead to a complete collapse if certain minimum heat values are not reached the afterburning, and also when heating up the catalyst device on the one hand To have high temperatures available, can in an advantageous development of the invention in Richtunq of Flow path running wires made of heat-resistant and material with good thermal conductivity, e.g. a chromium-nickel alloy, can be provided in the area of the base parts and carrier elements in an insulating compound with good heat storage properties are embedded and protrude outside this area into the flow path. These wires have the function that if there is still insufficient heat in the exhaust gases, the wires arranged on the inlet side provide energy absorb faster than the carrier elements and direct this energy to the outlet side, where it generates more heat is made available so that the afterburning process can be ignited at an earlier point in time. If, on the other hand, fluctuations occur during operation and the temperature drops below the catalytic ignition temperature, i.e. to extinguish the afterburning flame, in the lower range, is achieved by the Wires from the outlet end to which another higher amount of energy is available, heat is returned to the inlet side and leads to an increase there the temperature and thus either to maintain the afterburning flame or, if necessary, to re-ignite. The insulating compound made of ceramic material can be

, which has the advantage that there is a clear energy conduction within the wires and no return of energy between the exposed end regions of the Wires entering. To support this before and after

The number of wires can have an ignition effect that of the carrier elements correspond to the respective outer position of the support elements and are in the manner of bisectors extend relative to the carrier elements, so that they are placed in the middle of the gas flow.

According to a further advantageous embodiment can within the base parts and carrier elements in Wires running in the direction of the flow path and made of heat-resistant material with good heat and electrical conductivity, e.g. made of a chromium-nickel alloy, which in a core made of insulating, electrically non- conductive material such as ceramic material are embedded, this core from one to its outer surface spaced sheath surrounded and between the core and sheath

2Π a channel is formed. In from Outside controllable manner gases or other mixtures are introduced, which are added in the post-combustion process should be. For example, it can be oxygen to intensify combustion, or also to lime in powder form for the purpose of binding sulfur-like constituents in the afterburning Exhaust. Here too, in order to make favorable use of the flow direction predetermined by the carrier elements, the number of wires corresponds to that of the carrier elements of the outer layer on the outlet side and extend in the manner of bisectors relative to the carrier elements.

In this embodiment, the wires can be re-impacted function as igniter or preheating elements with electric current. To this end it will be beneficial

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at least two wires on the inlet side outside the stream mungsweges of the flammable substances to be catalyzed run and are connected to an energy source, while the exit-side ends as ignition resistors Π5 are trained. This can be done either by arranging coil-shaped resistors between the wire ends but it is also conceivable to generate an ignition by means of sparks between their ends.

1Π Execution a- fcJer invention proceed from the following Description of what is shown in the schematic drawing th exemplary embodiments. It shows

1 shows a cross section through an inventive - Appropriate facility for catalytic post-processing

burning,

FIG. 2 is a plan view of the device of FIG.

2Π Fig. 3 is a partial plan view of a Rasis-

element with a gradual adjustment device on a larger scale,

Fig. 4 is a side view of several juxtaposed q e Basic parts with the adjustment device

device of Fig. 3,

Fig. 5 shows a way of sheathing the fiction

proper facility,
30th

6 shows, in a partially axonometric view, a modified embodiment of the device according to the invention when used in a smoke gas duct and
35

Fig. 7 shows another embodiment for the

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components to be used according to the invention.

In Fig. 1 you can see an in a smoke exhaust O in Afterburning device used in the form of a tube the invention, which is composed essentially of a number (here six) strung together lawn parts 1, each of which carries a plurality of support members. In the present embodiment, each base part is 1 with six equally angularly spaced

Equipped in orderly carrier elements. The support elements have the shape of flat rods, fingers or wings and form catalyst surfaces 21. The base parts 1 have the shape of rings and exist together with those in this Example integrally molded onto them carrier elements made of ceramic material. The carrier elements 2 are with a suitable catalyst material, which can be, for example, a noble metal such as platinum coated. This Catalyst material can also be on the surface of the support elements 2 may be provided. The base parts 1 with their carrier elements are surrounded by a housing jacket 3, which in turn sits in the flue gas vent 0. As can be seen, the carrier elements 2 extend transversely to the direction of flow A of afterburning flue gas guided in the pipe 0. The carrier elements 2 are, as from Fig. 1 recognizable, arranged with their catalyst surfaces 21 inclined to the flow direction A in order to be as favorable as possible aerodynamic flow conditions, i.e. to allow the flue gas to be flushed as closely as possible. How one recognizes specifically from the plan view of FIG. 2, each ring-shaped base part carries in this embodiment six support elements extending outward in a star or beam shape. Adjacent base parts la, Ib, Ic, etc. so offset from one another that the Flue gas imposed a helical direction is and, as mentioned, the catalyst surfaces 21 as possible are intensely flowed around. In order to offset the

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up and down protruding ends of the wires 5 si as shown, angled, and thereby angeorrine that they each bisect the angle between the adjacent th support elements 2 form. You are so in the open

Π5 inlet and outlet cross-section for the flue gas in the or from the catalyst device. As a result of their thermal conductivity, the wires 5 have the effect that when the facility starts up, i.e. when the heating starts, the higher heat at the inlet relatively quickly

1Π side lead to the exit side and here to a riser Contribute to the ambient temperature, so that the without such wires initially still lower temperature on the output side is increased so that on the exit side ignition takes place at the outer carrier elements at a relatively earlier point in time. In the case of a Lowering of the temperature on the inlet side, e.g. at refueling or other irregularities moderate combustion, the temperature on the inlet side can drop significantly at times, which means the critical ignition temperature of the carrier on the inlet side elements can be fallen short of. In such a Trap, heat flows against the direction of flow A through the wires 5 from the outlet side to the inlet side back and contributes to an increase here in the reverse manner as described with regard to the start-up of the device the ambient temperature and thus to reach the ignition temperature again.

The wires 5 can, as can be seen in connection with the exemplary embodiment shown in FIG. 6, also fulfill another function. There is the inner surrounding these wires 5 and their core 6 with the channel R. Coat below the inlet end of the through Base parts 1 and support elements 2 led out and specific afterburning device from the flue gas vent 0 can be connected to a source of secondary gases, indicated by the

gerelemente 2 to each other and thus the direction of the Rauchgasleitunq to be able to change, a Verstellmöqlichkeit in the form of locking elements 4 is provided, which in detail from Fiq. 3 and 4 can be seen. It's about

Π5 balls in hollows on the outer surface of the ring Engage razor parts 1 and lock each adjacent base parts in a certain position. By arrangement Different settings are possible for several such troughs at certain intervals. It was

In the present example there is a 10o adjustment option provided, but it is of course possible, especially with larger diameters, a finer angle adjustment to be provided.

The housing jacket surrounding the device 3, which is also made of ceramic material, to the necessary To ensure heat resistance, as can be seen from Fig. 5, for the purpose of easy assembly of the The device is divided into segments and here consists of three shell parts 31, which are frictionally engaged when installed are held together by clamping rings 32. The housing jacket 3 has delimiting edge flanges 33 on, the inner diameter of which is slightly smaller than the outer diameter of the carrier elements, so that the base parts 1 with the support elements 2 are prevented from falling out of the jacket 3, but within the same in certain Be able to expand and move boundaries.

Through the inside of the attached razor parts 1 er-3D stretch wires 5 made of a highly thermally conductive material, which in a core 6 made of heat-insulating ceramic Material are embedded. This core is with suitable spacers, not shown in detail here, in an inner one Sheath 7, also made of ceramic material, held. The latter in turn is based on spacers on the inside of the base part 1. The ones from the core

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- Arrow B, to be closed. These secondary gases flow through the channel 8 and emerge on the outlet side for support the afterburning in this area. This makes it possible to carry out afterburning in this area

D5 of substances to contribute within the catalytic converter device have not been degraded by post-combustion. So it is also possible to the secondary gas stream B add powdery materials, for example lime, to a chemical compound on the outlet side, for example with sulfur. Furthermore, the wires 5, which are used here as wires with good electrical conductivity are provided and can be connected to an electrical energy source E in the lower area, for application of ignition resistors 9 with electrical current. These ignition elements 9 between the outlet ends of the wires 5 are connected, can lead to an additional heat generation in the exit area and thus a still contribute to more complete afterburning.

In Fig. 7 is a modified embodiment of the invention Device shown in which rod-shaped support elements 20 of similar training as 1 and 2 are located on segment-like base parts 10 and extend inwardly therefrom. Such Embodiment can possibly make the arrangement of a housing jacket 3 superfluous.

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Claims (21)

I r-JAOH <3ERE! O: -! T j 1) Uta Klein, Hindenburgstrasse 20/21, 2060 Bad Oldesloe 2) Gualterio A η ζ, Börnsener Straße 18, 2Ο55 Aumühle 3) Wolfgang Lüh r, Am Dorfplatz 1, 2061 Stubben Patent claims: Device for catalytic combustion, in particular afterburning of gases, exhaust gases, flue gases or similar combustible ones Substances. 1. Device for catalytic combustion, in particular afterburning of gases, exhaust gases, flue gases or the like combustible substances with a support structure (substrate) and a catalyst attached to this / wherein the The device is arranged in the flow path of the combustible substances, characterized in that that the device has at least one base part (1) carried by it and extending into the flow path Support elements (2) comprise ^ which form catalyst surfaces (21) directed transversely to the flow (A). 2. Device according to claim 1, characterized in that it has a plurality of shape and / or comprises base parts (1a, 1b, 1c) which can be joined together in a non-positive manner, from which the support elements (2) with their catalyst surfaces (21) extend radially into the flow path (A). 3. Device according to claim 1 or 2, characterized in that the base parts (1) as a cylinder shaped rings are formed, from which the carrier elements (2) extend radially outward. 4. Device according to claim 1 or 2, characterized in that the base parts as segments (10) a hollow body jacket are formed, of which -2-COPY the carrier elements (20) extend radially inward. 5. Device.nach claim 3 or 4, characterized in that a number of the base parts (1) are assembled such that the Trä'gerelemente (2) of adjacent base parts in the flow direction (1a, 1b, 1c) are offset from one another. 6. Device according to one of claims 1 to 5, characterized in that the carrier elements (2) as elongated flattened rods, spokes, lamellae, fingers, wings or the like. Are formed. 7. Device according to one of claims 1 to 6, characterized in that the carrier elements (2) are arranged with their catalyst surfaces (21) inclined to the flow (A) on the base parts (1). 8. Device according to one of claims 1 to 7, characterized in that the carrier elements (2) are integrally formed with the base parts (1). 9. Device according to one of claims 1 to 7, characterized in that the Träqerelemente (2) can be connected to the base parts (1) by a form fit. 10. Device according to one of claims 3 to 9, characterized in that the base parts (1) with the carrier elements (2) are surrounded and held by a multi-part housing shell (3) which is essentially in Direction of the flow path extends. 11. The device according to claim 10, characterized in that the jacket parts (31) non-positively are held together. 12. Device according to one of claims 1 to 11, characterized characterized in that in the direction of flow (A) COPY Adjacent base parts (1) with means (4) for gradually adjusting the angular position of their respective carrier elements (2) are provided to each other. 13. Device according to claim 1-2, characterized ,. that the adjusting means as positive locking elements (4) in the form of balls, pins, knobs Od. Like. Are provided with appropriate counter bearings. 14. Device according to one of claims 1 to 13, characterized characterized in that the base parts (1) and the support elements (2) made of heat-resistant material such as Ceramic or similar burnt earth exist. 15. Device according to one of claims 1 to 14, characterized in that, in the direction of the flow path (A) running, wires (5) made of heat-resistant and highly thermally conductive material, e.g. a chrome-nickel alloy, are provided in the area of the base parts (1) and support elements (2) in an insulating compound with auten Heat storage properties are embedded and protrude outside this area into the flow path (A). 16. Device according to claim 15, characterized that the insulating compound consists of ceramic material. 17. Device according to claim 15 or 16, characterized ge indicates that the number of wires (5) corresponds to that of the carrier elements (2) of the respective outer lae thereof correspond and extend in the manner of bisectors relative to the carrier elements. 18. Device according to one of claims 1 to 14, characterized characterized in that, within the base parts (1) and support elements (2) in the direction of the flow path running, wires (5) made of heat-resistant and good heat and electrically conductive material, e.g. made of a chrome-nickel alloy, are provided in a core (6) made of insulating, electrically non-conductive material such as 3AA63A2ΠΕ ^ ίίΐ:: .: ceramic material are embedded, this core (6) from a spaced to its outer surface Surrounding the inner jacket (7) and a channel (8) is formed between the core (6) and the inner jacket (7). 19. Device according to claim 18, characterized in that the wires (5) in their The number of the carrier elements (2) correspond to the outer layer on the outlet side and are in the manner of bisectors extend relative to the support elements. 20. Device according to claim 18 or 19, characterized characterized in that at least two wires (5) on the inlet side outside the flow path the flammable substances to be catalyzed run. 21. Device according to claim 20, characterized in that the wires (5) to a power source connected and their outlet ends are designed as ignition resistors (9). -5-