DE102007029667A1 - Catalyst support body for use as particle filters, super catalyst and coating catalyst for use in motor vehicle technology, comprises cylindrical jacket pipe, two spirally formed closing units and cylindrical foam body - Google Patents

Abstract

The catalyst support body comprises a cylindrical jacket pipe (104), two spirally formed closing units (107) and a cylindrical foam body made of a foam sheet (101). The foam sheet is simply folded and wrapped based on a formed folding edge (102) so that two half-spaces (103a,103b) separated by the foam sheet are present. The cylindrical foam body is arranged in the cylindrical jacket pipe and both the half-spaces are closed only at a front surface by a closing unit. The front surface has only one closing unit. An independent claim is also included for a method for producing a catalyst support body, which involves folding a foam sheet made of a metal, wrapping the foam sheet based on a folding edge formed after the folding so that the folding edge is present close to the center of a developed foam body, introducing and fixing the simply folded and wrapped foam sheet into a cylindrical jacket pipe, and arranging a spirally molded closing unit at the front surfaces of the half-spaces so that the half-spaces are alternately closed.

Description

The present invention relates to catalyst carrier bodies, the foam bodies from a folded and wound foam sheet comprising metal in a cylindrical casing pipe, through the folding and winding created two separate half-spaces are the front side by means of helical shutters are mutually closed. Furthermore, the present invention relates Invention catalyst carrier body comprising a foam plate a metal in a tubular casing with an approximately rectangular cross-section wherein the foam sheet is in a sheet structure and the foam plate perpendicular to the flow direction in the Jacket tube is arranged. Furthermore, the invention relates to a method for the preparation of catalyst carrier bodies.

catalysts are currently being used for the purification of exhaust gases from diesel or gasoline engines used in vehicle technology. The catalysts are either as full catalysts or as coating catalysts used. The full catalysts consist of 100 catalytic active material, whereas coating catalysts consist of a metallic or ceramic carrier with a surface coating consist. Typically, the catalyst support bodies used hitherto exist made of ceramic or metallic materials that are in one Jacket tube or the so-called Canning are located. In case of Coating catalysts become the catalyst carrier bodies with high-surface area porous catalytically active Coated metal oxides, which by means of a so-called "washcoat", d. H. by means of a slurry or dispersion of the metal oxides, mostly in powder form in a liquid, on the catalyst carrier body be applied. The catalytically active layer contains depending on the application often one or more catalytically active Metals, such as platinum, palladium, rhodium, nickel, Vanadium, tungsten, etc.

The present invention finds use for catalysts in automotive technology. Catalysts in the present case are understood as meaning both so-called diesel oxidation catalysts (DOC), urea hydrolysis catalysts, SCR catalysts (selective catalytic reduction), three-way catalysts or diesel particle filters which catalytically oxidize soot particles. When contacting the exhaust gas emitted from the engine with the catalytically active material, the reaction of unwanted constituents of the exhaust gas takes place. These include carbon monoxide, unreacted hydrocarbons, nitrogen oxides (NO _x ) or soot particles.

Catalyst support body are distinguished in wall-flow filter and flow filter. In a wall-mounted flow filter, the exhaust gas to be cleaned by a porous wall passed through while at a so-called flow filter to be cleaned exhaust gas the inner surface of a catalyst carrier body flows along.

at a wall-flow filter, also called "closed system", is the pollutant-containing exhaust gas in the penetration of a porous filter wall filtered. If the pollutants are soot particles, adsorb these on the surface of the filter wall or remain in the filter wall by means of depth filtration. For both cases, the particles do not pass through be recorded a screening effect. Thus, the pores of the Filters, through which flows the exhaust gas to be cleaned, not be smaller than the soot particles. Nonetheless the flow resistance in Wandstromfiltern very high. The difference in pressures in front of and behind a wall-flow filter is therefore very high. In other words, could it is said that the pressure drop is great.

Flow filter On the other hand, they typically consist of thin steel sheets with a targeted flow control technology. It slides the exhaust gas to be cleaned along the surface of the filter. Since the exhaust gas flow to be cleaned in the flow filter no must penetrate fine porous wall, is the pressure drop the exhaust stream when passing through the catalyst is less than the wall-flow filter.

It There is a fundamental interest, the benefits of Durchflußfiltern, namely a lower flow resistance and concomitantly a lower pressure drop, with the benefits of wall-flow filters, namely a more effective contacting of the exhaust gas stream to be cleaned with the catalyst surface or a better filtering effect, to combine.

Wall flow filters made of metals are known from the prior art, which ensure effective contacting of the exhaust gas flow to be cleaned with the catalyst surface. These catalyst carrier bodies usually consist of a metal foam. So revealed the EP-A-1344907 a device for removing carbon particles from exhaust gases, wherein the exhaust gas stream is passed through an open-pore and / or open-cell matrix consisting of a metal foam with a porosity between about 8 and 40 pores per cm.

The EP-A-0849444 also discloses a particulate filter for diesel engines, which consists of a three-dimensional net-like structure of a porous body made of a refractory metal, wherein the pore diameter, the thickness, the material packing density or the diameter of the filter ent vary long the flow direction of the filter.

A particle filter device with a foam body is also used in the DE-A-10351882 disclosed. The foam structure is characterized in particular by an increased electrical conductivity.

Further, the EP-A-1 400 274 a folded wire mesh filter that is simply folded and then wrapped. The cavities for the adsorption of particles are formed by the mesh of the wire mesh.

All In the cited disclosures included embodiments have the disadvantage that the pressure drop over the Catalyst carrier body because of the increased Flow resistance is very large.

Of the The invention was therefore based on the object, a catalyst carrier body to provide, in which one for the purification of the exhaust gas effective contact with the catalytically active surface is reached and the pressure drop at the catalyst carrier body as low as possible. Furthermore, the invention was the task based, a method for producing a catalyst carrier body provide.

The object is achieved by a catalyst carrier body which comprises a cylindrical casing tube, two closure elements formed as planar spirals and a cylindrical foam body consisting of a foam plate which is simply folded and wound starting from the formed folding edge, so that two separated by the foam plate half spaces be present, wherein the cylindrical foam body in the cylindrical casing tube ( 104 ) and each half space ( 103a . 103b ) only at one end face with a closure piece ( 107 ) is closed, each end face having only one closure piece.

These Arrangement of the components of the catalyst carrier body is characterized by the fact that separate half-spaces are present, which are mutually closed. An exhaust stream, which flows into the catalyst enters into and although the first half space of the wound catalyst carrier body a, then flows through the foam plate from a metal, as the first half space at the back with a gas-impermeable, a flat spiral formed closure piece is closed, occurs then into the second half space of the wound catalyst carrier body one, the front with a closure piece is closed, which also has the shape of a plane spiral, and then leaves after passing the second half space the catalyst. While the exhaust gas in the first half-space flows, the foam body acts as a flow filter, d. H. the exhaust gas initially flows parallel to the catalytically active Surface of the foam body simply folded and wrapped foam board. This pollutants are catalytic reacted or soot particles adsorb on the surface the foam plate. Subsequently, the exhaust gas flow penetrates the foam plate, while the catalyst carrier body acts analogous to a wall-flow filter, d. H. the exhaust gas passes the porous one Foam sheet. This pollutants are catalytically on the inner Implemented surface of the foam plate, or soot particles adsorb on the inner surface of the porous foam plate. Subsequently, the exhaust gas flows into the second half space parallel to the surface of the foam sheet, wherein the catalyst support body doing again analogous to a flow filter.

Of the catalyst carrier body according to the invention enables effective contact of the person to be cleaned Exhaust gas, wherein the pressure drop measured between gas inlet and Gas outlet of the catalyst is very low.

Foams of metal as used herein are, for example, from DE-A-102004014076 known, to which reference is made in full. However, other metal foams may also be used as the carrier. The term "metal foam" thus means a foam material of any metal or any alloy of metals, which may optionally contain other additives such as carbides, etc.

The Metal foams have a multiplicity of pores with each other are connected so that a gas through the foam material can be passed through.

The Foams can be made, for example, of iron / chromium / nickel alloys or consist of iron / chromium / nickel / aluminum alloys. These Alloys have a good relationship between the parameters strength, brittleness and flexibility.

The Production of such metal foams happens, for example, by mixing metal powder with a metal hydride, which then by hot pressing or extrusion to a molding material be compacted.

This Molding material is then at a temperature above the melting point heated to the metal, wherein released by the hydride hydrogen is, whereby the mixture is foamed.

Further possibilities for the production of metal foams are mentioned in the above mentioned patent described registration.

It can z. B. a gas are blown into a molten metal, the previously made foamable by adding solid ingredients ge has been. For aluminum alloys, stabilization typically becomes 10 to 20 vol.% Silicon carbide or alumina added.

In In a preferred embodiment, the pores in the Foam sheets have a mean size of 450 to 2500 microns, more preferably 800 to 1200 microns. at this average pore size results in a effective contact between the exhaust gas and the catalytically active surface, wherein the pores are not too small, so that the flow resistance is kept low.

The foam sheets of the catalyst support body according to the invention has a density of 0.1 to 0.9 g / m ³ . This density is the bulk density of the metal foam, that is, the quotient of the mass of the foam sheet and its outer volume is determined, which results from the outer dimensions of the metal foam. This density therefore includes an average density of the metal and the porous spaces in the metal foam.

According to one preferred embodiment of the invention the thickness of the foam plate of the catalyst carrier body between 0.1 and 5 mm, more preferably 0.5 and 3 mm and more preferably 1 to 2 mm. Foam sheets in this thickness can be procedurally most advantageous edit.

According to one Another preferred embodiment of the invention the foam plate of the catalyst carrier body coated. The coatings include, depending on the field of application a catalytically active metal such as platinum, palladium, Rhodium, nickel, vanadium, tungsten, etc. as well as high surface area porous metal oxides produced by means of a so-called "washcoat", a slurry or dispersion in a fluid phase the carrier can be applied.

Of the catalyst carrier body according to the invention thus finds use for unsupported catalysts as well for coating catalysts.

The Both half spaces are created by the simple folding of the Foam plate and the subsequent winding the easy folded foam sheet starting from the resulting folding edge. Strictly speaking, the half-spaces are only after arranging the foam plate in the cylindrical casing only on the both end faces of the cylindrical body open. The half-spaces are through the one foam plate and on the outer surface of the foam body limited by the jacket tube.

According to one another embodiment of the invention the wound layers of the foam plate are spaced so that the hemisphere bounded by the foam plate an inside dimension of Foam plate to foam plate from 0.5 to 10 mm, preferably from 1 to 5 mm, has. Half-spaces of this thickness, d. H. Half-spaces, in which the windings of the foam plate have the above-mentioned spacing, have proven to be particularly advantageous. When the halfpaces have an internal dimension of less than 0.5 mm, the exhaust pressure increases in front of the catalyst carrier body. Catalyst carrier body, at which the half-spaces have an inside dimension of more than 10 mm, characterized by too short contact times of the cleaned Off exhaust.

• a) eine Schaumplatte aus einem Metall einfach gefaltet wird,
• b) die einfach gefaltete Schaumplatte ausgehend von der gebildeten Faltkante gewickelt wird, so daß sich die nach dem Fal ten entstandene Faltkante nahe dem Zentrum des entstehenden Schaumkörpers befindet, und nach dem Wickeln zwei durch die Schaumplatte begrenzte Halbräume entstehen,
• c) die einfach gefaltete und gewickelte Schaumplatte in ein zylindrisches Mantelrohr eingeführt und in dem Mantelrohr fixiert wird,
• d) an den beiden Stirnflächen der Halbräume jeweils ein als ebene Spirale ausgeformtes Verschlußstück angeordnet wird, so daß die Halbräume wechselseitig verschlossen sind.

The object underlying the invention is further achieved by a method for producing a catalyst carrier body in which

• a) a foam sheet of metal is simply folded,
• b) the singly folded foam sheet is wound starting from the formed fold edge, so that the folding edge formed after folding is close to the center of the resulting foam body, and after winding, two half spaces defined by the foam sheet arise,
• c) the simply folded and wound foam plate is introduced into a cylindrical jacket tube and fixed in the jacket tube,
• d) is arranged at the two end faces of the half spaces each formed as a flat spiral closure piece, so that the half-spaces are mutually closed.

As already explained above, the two separate half spaces are created in that the foam sheet is simple (in the sense of once) is folded and then to the foam body wound foam sheet is introduced into a jacket tube. The half-spaces are merely after these process steps still on the end faces of the resulting cylindrical Body open. By each a closure piece closes a hemisphere in the form of a flat spiral, arise two half-open on one side half spaces. Possibly the plane spiral covers one half space and the end face of the Foam plate off.

In order to ensure that the foam plate during winding actually maintains a distance to a further inner winding of the foam plate, so that half-spaces, in a preferred embodiment of the method according to the invention in step b) the folded foam plate wound together with a spacer who the one which spaces the respective layers of the foam sheet during winding. The problem with winding without the use of a spacer may be that the wound foam layers contact their surfaces and no half space is in the foam winding ent. In a particularly preferred embodiment of the method according to the invention, the spacer can be removed after step b) from the wound foam sheet. As a spacer, for example, a corrugated layer can be used, which is wrapped together with the simply folded foam plate.

advantageously, the spacer is designed so that the distance of the half-spaces limiting foam boards between 0.5 and 10 mm, more preferably between 1 and 5 mm.

According to one preferred embodiment, the foam sheet before step a) perforated. Through the perforation, the foam plate is permeable and the flow resistance that the exhaust flow overcome must, sinks.

Possibly the foam body is coated. This may help with help a dipping process or by spraying into one or with a washcoat suspension after step b) or step c) become. The catalyst carrier body coated with the washcoat suspension must then be dried and calcined.

Further The invention was based on the object, a catalyst support to provide, in which one for the purification of the exhaust gas effective contact with the catalytically active surface the catalyst is achieved, wherein the pressure drop in the catalyst As low as possible, and the catalyst is an approximately rectangular Has cross-section to a room design of the catalyst on the motor vehicle allow the type-specific installation requirements bill wearing.

These The object is achieved by a catalyst carrier body comprising a foam plate of a metal and a jacket tube of approximately rectangular cross-section wherein the foam sheet has a sheet structure and the foam sheet arranged perpendicular to the flow direction in the jacket tube is.

With rectangular cross section is meant that the area, the flow of exhaust gas flows perpendicularly rectangular, where "roughly" means that the edges of the rectangle can be rounded and the walls of the jacket pipe do not have to collide exactly at 90 ° angle.

A Folder structure arises when a foam sheet is in recurring Intervals at parallel bending edges alternately is folded in a clockwise and counterclockwise direction. there kinks occur at a certain angle. In the side view results in a zigzag pattern. According to one preferred embodiment of this variant of the catalyst carrier body the bending edges have a distance of 1 to 15 cm and the angle is between 20 and 70 °. This results in pockets, in which, in the case of using the catalyst carrier body as a particulate filter can deposit carbon black.

in the Catalyst, the foam sheets are perpendicular to the bending edges flowed through the exhaust gas to be cleaned. Due to the Folder structure of the foam sheets are in some way wall-flow filters and flow filter combined. In the operation of the catalyst the exhaust gas to be cleaned initially flows along the surface of the foam sheet before passing through the foam sheet passes. Thus, in turn, the advantages of Wandstromfiltern and Flow filters are combined.

According to a preferred embodiment, the average pore size in the foam sheets is 450 to 2500 microns, preferably 800 to 1200 microns. The foam sheets have a density of 0.1 to 0.9 g / cm ³ . The density is determined as described above. The thickness of the foam sheet is in the range between 0.1 and 5 mm, more preferably 0.5 and 3 mm, even more preferably 1 and 2 mm. Foam boards with these features have proven to be particularly advantageous in terms of pressure drop and effective cleaning.

According to one preferred embodiment of the invention is the foam plate coated. This embodiment of the invention is also suitable for both unsupported catalyst carriers as well for coating catalysts.

These Catalyst carrier body with foam sheets in folder structure have the advantage that different foam plates in the Jacket tube can be arranged one behind the other. So can two foam plates in the flow direction be arranged one behind the other, the different middle Have pore sizes or with different Coatings are provided.

foam sheets in leaflet structure can advantageously z. B. by Corrugation be made. In the case of coating catalysts the foam sheets in leaflet after bending with a washcoat suspension coated, then dried and calcined before they are placed in the jacket tube.

The invention is further illustrated by the following figure and the following description explained, without this being to be understood as limiting.

1 and 2 show a catalyst support body according to the invention.

In 1 is a catalyst carrier body 100 shown. This consists of a foam plate 101 , which is simply folded, so that a folding edge 102 arises. This is according to the invention near the center of the wound foam body. By simply folding the foam plate 101 is wound, arise the two half-spaces 103a and 103b , The simply folded and wound foam plate is in a jacket tube 104 arranged. The two half-spaces 103a and 103b are open in the picture at their faces. According to the invention, the half-spaces are mutually connected by spiral-shaped closure pieces 107 covered. 1 indicates by the dashed lines the closing of the half-space 103b at. Not shown is the closing of the half-space 103a with another closure piece 107 at the back of the catalyst carrier body 100 , Due to the mutual closing of the half-spaces, two chambers are created by the foam plate 101 are separated from each other. An exhaust gas stream, which flows into the first half-space, is forced through the foam plate 101 to flow through, since the first half-space is closed by the rear closure piece. Thereafter, the partially purified exhaust gas flows through the second half space, and then exits the catalyst carrier body. 1 further indicates with the reference numerals 105 and 106 the inside dimension of a half-space 103a from one foam plate winding to the next or the thickness of the foam plate 101 at.

2 shows the cross section of a catalyst carrier body 200 with a foam plate 201 in leaflet structure, with the foam plate 201 in a jacket pipe 204 is arranged. The arrows indicate the flow direction of the exhaust gas to be cleaned. The reference numerals 202 and 203 indicate the distance between the bending edges and the angle of the kinks. According to the invention, a plurality of foam sheets can be arranged one behind the other in the flow direction (not shown).

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - EP 1344907 A [0008]
• - EP 0849444 A [0009]
• - DE 10351882 A [0010]
• EP 1400274A [0011]
• - DE 102004014076 A [0017]

Claims (19)

Catalyst carrier body ( 100 ) comprising a cylindrical casing tube ( 104 ), two as spiral spirals formed closure pieces ( 107 ) and a cylindrical foam body consisting of a foam plate ( 101 ), which is simply folded and starting from the formed folding edge ( 102 ) is wound so that two separated by the foam plate half spaces ( 103a . 103b ), wherein the cylindrical foam body in the cylindrical casing ( 104 ) and each half space ( 103a . 103b ) only at one end face with a closure piece ( 107 ) is closed, each end face having only one closure piece. Catalyst carrier body ( 100 ) according to claim 1, characterized in that the foam plate ( 101 ) has a mean pore size of 450 to 2500 microns, preferably 800 to 1200 microns. Catalyst carrier body ( 100 ) according to claim 1 or claim 2, characterized in that the foam plate ( 101 ) has a density of 0.1 to 0.9 g / m ³ . Catalyst carrier body ( 100 ) according to one of the preceding claims, characterized in that the foam plate ( 101 ) has a thickness in the range between 0.1 and 5 mm, preferably 0.5 to 3 mm, more preferably 1 to 2 mm. Catalyst carrier body ( 100 ) according to one of the preceding claims, characterized in that the cylindrical foam body is coated. Catalyst carrier body ( 100 ) according to one of the preceding claims, characterized in that the wound layers of the foam board ( 101 ) are spaced so that through the foam plate ( 101 ) limited half space ( 103a . 103b ) has an internal dimension of foam plate to foam plate of 0.5 to 10 mm, preferably from 1 to 5 mm. Catalyst carrier body ( 200 ) comprising a foam plate ( 201 ) of a metal and a jacket tube ( 204 ) of approximately rectangular cross-section, characterized in that the foam plate ( 201 ) has a leaflet structure and the foam plate ( 201 ) perpendicular to the flow direction in the jacket tube ( 204 ) is arranged. Catalyst carrier body ( 200 ) according to claim 7, characterized in that the foam plate ( 201 ) has a mean pore size of 450 to 2500 .mu.m, preferably 800 to 1200 .mu.m. Catalyst carrier body ( 200 ) according to claim 7 or claim 8, characterized in that the foam board ( 201 ) has a density of 0.1 to 0.9 g / m ³ . Catalyst carrier body ( 200 ) according to one of claims 7 to 9, characterized in that the foam plate ( 201 ) has a thickness in the range between 0.1 and 5 mm, preferably 0.5 to 3 mm, most preferably 1 to 2 mm. Catalyst carrier body ( 200 ) according to one of claims 7 to 10, characterized in that the foam board ( 201 ) is coated. Catalyst carrier body ( 200 ) according to any one of claims 7 to 11, characterized in that a plurality of foam sheets with folded sheet structure are arranged one behind the other in the flow direction, wherein the foam sheets have different average pore sizes. Method for producing a catalyst carrier body, by doing a) a foam sheet of a metal simply folded becomes, b) the simply folded foam plate starting from the formed folding edge is wound, so that after the wrinkle fold formed near the center of the resulting Foam body is located, and after winding two by the foam plate creates limited half-spaces, c) the simply folded and wrapped foam sheet into a cylindrical one Jacket tube introduced and fixed in the jacket tube, d) one at each of the two end faces of the half-spaces arranged as a flat spiral shaped closure piece so that the half-spaces are mutually closed are. Process for producing a catalyst carrier body according to claim 13, characterized in that in step b) the simply folded foam sheet is wound together with a spacer which spaces the sheets of foam sheet during winding. Process for producing a catalyst carrier body according to claim 14, characterized in that the spacer after step b) is removed from the foam plate. Process for producing a catalyst carrier body according to claim 14 or claim 15, characterized in that the Spacer is a Welllage. A process for the preparation of a catalyst support body according to any one of claims 13 to 16, characterized in that the wound layers of the foam sheet are spaced so that the Half space defined by the foam plate has an internal dimension of 0.5 to 10 mm, more preferably 1 to 5 mm. Process for producing a catalyst carrier body according to one of claims 13 to 17, characterized the foam sheet is perforated before step a). Process for producing a catalyst carrier body according to one of claims 13 to 18, characterized that the foam sheet after step b) or after step c) is coated.