EP2018221A1 - Corps de support pour le traitement ultérieur des gaz d'échappement avec un ensemble disperseur-catalyseur - Google Patents

Corps de support pour le traitement ultérieur des gaz d'échappement avec un ensemble disperseur-catalyseur

Info

Publication number
EP2018221A1
EP2018221A1 EP07724961A EP07724961A EP2018221A1 EP 2018221 A1 EP2018221 A1 EP 2018221A1 EP 07724961 A EP07724961 A EP 07724961A EP 07724961 A EP07724961 A EP 07724961A EP 2018221 A1 EP2018221 A1 EP 2018221A1
Authority
EP
European Patent Office
Prior art keywords
carrier body
coating
catalyst
exhaust gas
flow path
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP07724961A
Other languages
German (de)
English (en)
Inventor
Peter Hirth
Thomas HÄRIG
Rolf BRÜCK
Holger Stock
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Vitesco Technologies Lohmar Verwaltungs GmbH
Original Assignee
Emitec Gesellschaft fuer Emissionstechnologie mbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Emitec Gesellschaft fuer Emissionstechnologie mbH filed Critical Emitec Gesellschaft fuer Emissionstechnologie mbH
Publication of EP2018221A1 publication Critical patent/EP2018221A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J35/00—Catalysts, in general, characterised by their form or physical properties
    • B01J35/50—Catalysts, in general, characterised by their form or physical properties characterised by their shape or configuration
    • B01J35/56—Foraminous structures having flow-through passages or channels, e.g. grids or three-dimensional monoliths
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
    • B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
    • B01D53/9445—Simultaneously removing carbon monoxide, hydrocarbons or nitrogen oxides making use of three-way catalysts [TWC] or four-way-catalysts [FWC]
    • B01D53/945—Simultaneously removing carbon monoxide, hydrocarbons or nitrogen oxides making use of three-way catalysts [TWC] or four-way-catalysts [FWC] characterised by a specific catalyst
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
    • B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
    • B01D53/9445—Simultaneously removing carbon monoxide, hydrocarbons or nitrogen oxides making use of three-way catalysts [TWC] or four-way-catalysts [FWC]
    • B01D53/9454—Simultaneously removing carbon monoxide, hydrocarbons or nitrogen oxides making use of three-way catalysts [TWC] or four-way-catalysts [FWC] characterised by a specific device
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
    • B01J23/40—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals of the platinum group metals
    • B01J23/42—Platinum
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
    • B01J23/40—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals of the platinum group metals
    • B01J23/44—Palladium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
    • B01J23/40—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals of the platinum group metals
    • B01J23/46—Ruthenium, rhodium, osmium or iridium
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/24—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by constructional aspects of converting apparatus
    • F01N3/28—Construction of catalytic reactors
    • F01N3/2803—Construction of catalytic reactors characterised by structure, by material or by manufacturing of catalyst support
    • F01N3/2807—Metal other than sintered metal
    • F01N3/281—Metallic honeycomb monoliths made of stacked or rolled sheets, foils or plates
    • F01N3/2814—Metallic honeycomb monoliths made of stacked or rolled sheets, foils or plates all sheets, plates or foils being corrugated
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/10—Noble metals or compounds thereof
    • B01D2255/102—Platinum group metals
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/20—Metals or compounds thereof
    • B01D2255/206—Rare earth metals
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/20—Metals or compounds thereof
    • B01D2255/209—Other metals
    • B01D2255/2092—Aluminium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/90—Physical characteristics of catalysts
    • B01D2255/92—Dimensions
    • B01D2255/9202—Linear dimensions
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2258/00—Sources of waste gases
    • B01D2258/01—Engine exhaust gases
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2330/00—Structure of catalyst support or particle filter
    • F01N2330/02—Metallic plates or honeycombs, e.g. superposed or rolled-up corrugated or otherwise deformed sheet metal
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
    • Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies

Definitions

  • the present invention relates to a carrier body for a catalytically active coating.
  • Such carrier bodies are used in particular for the aftertreatment of exhaust gases in vehicles.
  • such support bodies are in particular designed so that it is constructed with at least one at least partially structured layer of a gas-impermeable material, so that a plurality of flow paths is present with a minimum cross-section of 0.5 mm, wherein at least the majority of the flow paths are designed with multiple passages towards at least one adjacent flow path.
  • the effectiveness of such carrier bodies with regard to the conversion of pollutants contained in the exhaust gas is influenced by a multiplicity of different criteria. Two essential requirements are an effective mass transport of the pollutants towards the catalytically active coating and a low back pressure, which is generated in the exhaust gas flow due to the flow through the carrier body.
  • a carrier body is to be specified, whose coating is aligned with the turbulent flow conditions in the interior of the carrier body and enables a more effective conversion of pollutants in the exhaust gas.
  • a method for producing a coated catalyst carrier body is to be specified, with which a particularly uniform coating can be achieved, so that it has only a small influence on the flow behavior of the exhaust gas during operation.
  • the carrier body according to the invention has an overall support surface comprising at ⁇ least a coating portion with a catalytically active coating and at least one kind of catalyst elements, which disperse to an upper ⁇ surface of the support body are arranged, wherein: - the catalyst elements have a mean distance along the surface of at least 3 Micrometer [ ⁇ m], the surface has a mean surface roughness R 2 of 2 to 10 micrometers [ ⁇ m], and the carrier body compared to a carrier body with a smooth and uncoated surface has a maximum pressure loss increase of 25%.
  • the carrier body can be made use of a variety of different concepts.
  • a gas permeable monoliths may be formed, which have a defined number, position, etc. of flow paths, but it is also possible that the monolith with a random (chaotic) cavity structure, for. is formed in the manner of a foam or the like.
  • the support body is penetrated by a gas flow, which enters on one side and exits on a (other) side again.
  • the gas stream is passed through the material surfaces delimiting the flow paths and / or the cavity structure.
  • the total support surface comprises the surface of these walls of the flow paths or the inner material surfaces, and substantially coincides with the so-called “geometric surface” (GSA) of the support body.
  • GSA geometric surface
  • catalyst element is intended in particular to describe particle-like structures to which a medium size can be assigned.
  • the outer shape of the catalyst elements is user-selectable, with an approximately spherical shape being preferred.
  • These catalyst elements are now dispersed on the surface (ie the part of the total support surface which is in the coating arranged portion), which should mean, essentially, that no surface closed coating should be present. Rather, the Kataly ⁇ sator elements at least partly, but preferably completely individually to or applied to the surface.
  • the arrangement of the catalyst elements is carried out according to the invention on the surface so that they have a mean distance along the surface of at least 3 microns, preferably in a range of 3 to 9 microns.
  • the mean distance the following must be taken into account: First of all, this means an averaged value as it exists in a representative area of the coating section. Furthermore, the distance refers to an indication along the surface, not to a pure distance indication.
  • the mean distance along the surface is comparable to the way that the exhaust flow must flow from one catalyst element to an adjacent catalyst element along the surface.
  • the average distance should be at least in the range of the size (1 ⁇ D) of the catalyst element to twenty times (20 ⁇ D) of the size (D) of the catalyst element. This avoids, in particular, the fact that the dispersively distributed catalyst elements combine with one another under ambient conditions at high temperatures, and consequently the catalytically active surface is reduced.
  • the surface has an average roughness R z of 2 to 10 .mu.m, in particular from 3 to 6 .mu.m.
  • the mean roughness R z relates at least to a representative region of the coating section, if appropriate also to the entire surface.
  • the average roughness depth R z is understood to be the arithmetic mean of a plurality of (usually 5) individual roughness depths which touch the distance between two parallels within a single measuring section of a roughness profile at the highest and at the lowest point.
  • the support body with respect to a support body with a smooth or uncoated surface has a maximum pressure loss increase of 25%, in particular of at most 15%.
  • the roughness depth R z is substantially uniform with slight tolerances, so that a uniform reaction behavior in the coating section can be maintained even with long-term use of the carrier body.
  • a smooth or uncoated surface means, in particular, the surface quality of the materials used which regularly have a mean roughness depth R z (along the rolling direction) in the range of at most 1 ⁇ m (smooth).
  • At least a support body can be used with such a surface as a reference.
  • the pressure in the test exhaust system behind the carrier body 1, 25 bar. In this case, the pressure drop over the carrier body is determined.
  • the catalyst elements are arranged in an amount of 0.2 to 2.0 grams per square meter [g / m 2 ] of the total support surface.
  • the amount of 0.2 to 2.0 g / m 2 [grams per square meter] of total carrier area che is designed nen particular the exhaust gas treatment of mobile Verbrennungskraftmaschi ⁇ , eg for a cleaning of gasoline or diesel exhaust.
  • Very particularly preferred is a range of 0.4 to 0.8 g / m 2 for the noble metal catalyst platinum. If the loading set lower, at a unfavorable composition could occur of the exhaust gas to be cleaned under certain circumstances Unzu ⁇ reaching conversion of the pollutants. If the loading exceeds the specified range, superimposition of the noble metal catalysts may occur so that no further increase in the catalytic activity but only in the production costs occurs.
  • the type of catalyst elements comprises a noble metal catalyst from the group of platinum, palladium and rhodium.
  • the average size of the catalyst element is preferably in the range of 5 to 10 nanometers [nm],
  • this is constructed with at least one at least partially structured layer of a gas-impermeable material, so that a plurality of flow paths with a minimum cross-section of 0.5 Quadratmil- limeter [mm 2 ] is present wherein at least the majority of the flow paths are configured with multiple passages towards at least one adjacent flow path.
  • the carrier body is preferably a so-called honeycomb body whose flow paths are formed with a plurality of substantially straight, parallel to each other arranged channels.
  • These flow paths or channels can be formed with one or more layers of a gas-impermeable material. It is both possible that completely structured and / or completely smooth layers are provided, but there are also mixed layers with partially formed structures possible.
  • the gas-impermeable material it should be noted that this regularly has a high-temperature turfestes and corrosion resistant material is. Both (not ⁇ porous) ceramics, such as metal oxides, as well as metals can be employed which can withstand these conditions.
  • the flow paths are provided with a minimum cross section of 0.5 mm 2 .
  • the minimum cross section is at least 0.8 mm 2 or even 1.0 mm 2 .
  • this minimum cross section refers to an average over the entire length of the flow path, the minimum cross section locally reducing internals (dents, vanes, etc.) are not taken into account.
  • the minimum cross section preferably concerns just the area of the flow paths in which there are no internals, guide surfaces, flow path constrictions and the like.
  • the majority of the flow paths have multiple passages toward at least one adjacent flow path.
  • all flow paths are provided with a plurality of passages.
  • the passages can realize a connection to the directly adjacent flow path, for example, in which the passages of the layer itself are formed and thus allows a flow of exhaust gas through to directly adjacent flow path.
  • the passages can be produced by mere deformation of the layer, wherein, for example, the directly adjacent channel can be skipped and the second-through flow path can be penetrated.
  • the passages have the function of diverting or swirling exhaust gas flowing through the carrier body transversely thereto in a preferred main flow direction, so that the exhaust gas or the partial exhaust gas streams can change the flow path several times.
  • At least one coating section of the total carrier surface is provided with a catalytically active coating.
  • the coating section may be part of a layer, but it is preferred that the entire carrier body has such a coating section over a portion of its axial extent. In other words, this means that all flow paths are provided with a coating in a longitudinal section (with respect to the carrier body in the same section of its axial extent).
  • a coating section of, for example, at most 30 mm or even only 20 mm is catalytically active starting from the end face of the carrier body in its depth.
  • the entire total support surface is designed with a catalytically active coating.
  • the carrier body has at least one coating section of the total carrier surface, which is provided with a catalytically active coating which has a coating thickness of at most 15 micrometers [ ⁇ m]. It has been found that the otherwise usual diffusion processes for the conversion of pollutants in the exhaust gas as a result of the turbulent flows inside the support body no longer take place in the usual way. On the one hand, the significant reduction of the coating thickness results in an increased hydraulic diameter of the flow path, so that a smaller pressure loss with respect to the flow through the carrier body of exhaust gas is achieved. On the other hand, the coating can now be carried out with an adapted distribution of the catalytically active regions near the surface, so that there the catalytic conversion of the pollutants can be further improved.
  • the coating thickness can be significantly reduced, for example to at most 8 microns or at most 1 micron.
  • a E- delmetall catalyst is provided at least from the group of platinum, palladium and rhodium only in a surface boundary layer of a boundary layer thickness of at most 1 Mikrome ⁇ ter [microns].
  • the noble metal catalyst is provided practically only on the surface of the coating.
  • the boundary layer thickness can be made even smaller, for example at most 0.1 microns. The limitation of the boundary layer thickness thus illustrates how reactive the surface boundary layer is, whereby doping of noble metal catalysts deep in the (inactive) interior is avoided.
  • the coating comprises a porous storage layer, wherein in the at least one coating section is provided between 5 and 30 grams per square meter [g / m 2 ] thereof. Very particular preference is given to a range of 10 to 20 g / m 2 .
  • the porous storage layer provides an oxygen storage capability which is realized, for example, by what is known as washcoat [with Al 2 O 3 ] or cerium oxide [CeO].
  • washcoat with Al 2 O 3
  • CeO cerium oxide
  • This storage layer advantageously has a coating thickness of at most 10 ⁇ m [micrometers], preferably only 6 ⁇ m, wherein it may be substantially free of noble metal catalysts.
  • a storage layer comprising a zeolite as a hydrocarbon storage is proposed, in the case of a gasoline engine an oxygen storage (cerium / zirconium oxide).
  • a surface boundary layer with a noble metal catalyst with the specified distance from each other an application-oriented storage layer and a interposed barrier layer, which prevent undesired interaction of Ab ⁇ gas components in the surface and the storage layer.
  • microtechnology also known as microstructure technology
  • nanotechnology deals with processes for the production of bodies and geometrical structures with dimensions in the micrometer range (0.1 ⁇ m - 1000 ⁇ m).
  • nanotechnology is used as a generic term for a wide range of technologies dedicated to the production of objects and structures smaller than 100 nanometers (ran). With these methods, the coatings can be targeted and defined build.
  • the flow paths are at least partially limited by a knitted fabric made of wire filaments.
  • the carrier body is formed with a predetermined number of completely structured layers and a corresponding number of knitted fabrics made of metallic wire filaments, wherein the structured layers and the knits are arranged alternately to one another.
  • the structure of the layer forms together with the fabric boundaries or walls for the flow paths.
  • filtering of the partial gas streams flowing through the flow paths can be effected, for example, by creating with the structured layer cross-sectional constrictions of the flow paths which at least partially penetrate the partial gas flow into the fabric or even through it.
  • the term "fabric” is understood here as überge ⁇ arranged term for various types of a network of wire filaments: tangle, woven, knitted, fleece, etc., which verharkt together, welded, soldered, sintered, etc. . could be.
  • the at least one at least partially structured layer comprises a stainless steel foil.
  • a stainless steel foil which contains about 18-22% by weight chromium, about 4.5-6% by weight aluminum, additions of titanium, yttrium and zirconium between about 0.04 and 0.08% by weight. % and iron as base.
  • This high-temperature-resistant and corrosion-resistant material has already proven itself for known catalyst carrier bodies in the automotive sector.
  • the roughness of the wire filaments and / or the stainless steel foil is in the range of 3 to 6 microns.
  • At least the wire filaments or the stainless steel foil comprises aluminum as constituent, which is formed in at least one coating section as surface oxide. It is preferred that both the wire filaments and the stainless steel foil are formed with an aluminum oxide on the surface. This means in particular that the precious metals steel foil or the wire filaments are thermally treated, so that from the metal in the aluminum on the surface aluminum oxide is formed.
  • a suitable surface oxide (such as, in particular so-called gamma or teta-A12O3) can be achieved, for example, for the subsequently specified stainless steel foils in that the stainless steel foil with a thickness of 50 microns [micrometer] for 70 hours at 900 ° C in air or at 925 ° C is treated on a gas mixture consisting of argon and 4 wt .-% H2 and 7 wt .-% H2O.
  • the examined stainless steel foils are once the material "Fecralloy" (Fe: 72.3% by weight, Cr: 22.0% by weight, Al: 5.10% by weight, Si: 0 , 42% by weight, Hf: less than 0.01% by weight, Mg: 0.003% by weight, Mn: 0.10% by weight, Ti: 0.051% by weight, Y: 0.074% by weight; %, Zr: 0.077% by weight, C: 0.048% by weight, S: less than 0.001% by weight, N: 0.0180% by weight, O: 0.0160% by weight) or Aluchrom YHf (Fe: 72.0 wt%, Cr: 20.5 wt%, Al: 5.39 wt%, Si: 0.29 wt%, Hf: 0.026 wt% Mg: 0.008 wt%, Mn: 0.12 wt%, Ti: 0.005 wt%, Y: 0.041 wt%, Zr: 0.055 w
  • At least one noble metal catalyst from the group of platinum, palladium and rhodium is applied directly to at least the wire filaments or the stainless steel foil.
  • the noble metal catalysts are applied substantially uniformly to the wire filaments and the stainless steel foil.
  • On a storage layer is omitted at this point. This results, for example, in a coating height of less than 30 nm [nanometer], in particular in the range of 0.5 to 20 ⁇ m.
  • each flow path has a length and this has over the length seen in a Wiederholungsinter ⁇ interval of at most 20 mm passages.
  • a passage is provided towards an adjacent flow path.
  • baffles may be formed, for example, by stamping or denting the layer in the (adjacent) surrounding region of a passage.
  • the holes have a hole cross-section of at least 25 square millimeters [mm 2 ].
  • An embodiment of the hole cross-section of at least 50 mm 2 is particularly preferred.
  • the holes are made round, holes with a hole diameter of at least 8 mm [mm] are preferred.
  • These large holes extend regularly over the walls of several flow channels, so that adjacent walls are opened at the same time and a cross-flow is possible.
  • a discharge directed towards the hole takes place. steering, which leads to the further division of the partial gas flows. This effect is improved with increasing hole cross section.
  • the sum of the open hole cross sections ⁇ at least 30% of a closed position corresponding surface is also proposed that at least half of the layers is designed with solu- brass.
  • This embodiment is preferred, for example, when the carrier body is designed with smooth and corrugated layers, in which case in particular the smooth layers are executed with holes and the corrugated layers provide passages with guide surfaces or indentations.
  • at least 30% of a closed ply surface is to be made with holes, it is intended to illustrate how many such holes are to be provided per ply.
  • the sum of the open hole cross-sections should not exceed a value of 50% of the closed layer surface.
  • the closed layer surface relates in particular to the layer surface of the layer, if no openings were provided.
  • a carrier body in which the flow path is designed so that a gas flowing therethrough is turbulent over at least 80% of the length of the flow path.
  • the majority and very particularly preferably all flow paths of the carrier body are preferably designed accordingly.
  • the use of the coating according to the invention has proven itself.
  • a method for producing a carrier body with an overall surface comprising at least one coating section with a catalytically active coating which comprises at least the following steps:
  • the method is suitable in particular for the production of a carrier body previously described in accordance with the invention, to which extent reference may always be made to these explanations.
  • Step a) comprises, in particular, the provision of a metallic honeycomb body which is formed with at least one at least partially structured film.
  • Step b) is stirred in particular in the manner already explained above.
  • the carrier body can be at least partially disassembled and / or combined with other components.
  • thermal treatments oxidation, heating, etc.
  • welding, brazing, gluing, etc. can be carried out. It is also possible to repeat steps b) and c) until there is a desired pressure loss increase, before starting with step d).
  • step b) it is not absolutely necessary to carry out step b) in view of mass production of such carrier bodies; In the case of established boundary conditions, it can be assumed that the carrier bodies from step a) always result in the same pressure loss and step c) the same pressure loss increase and therefore these characteristic values no longer have to be determined individually.
  • step c) comprises at least one of the following processes: c) mechanical surface treatment, c2) surface oxide formation, c3) surface coating, c4) nanotechnology surface application of material (35).
  • the process c1) includes, for example, an abrasive treatment of the surface (grinding, scratching, etc.); Step c2) relates in particular to the cultivation of aluminum oxides, as already explained above.
  • the processes c1) and c2) relate primarily to processing steps which relate to a change in the roughness profile of the base material of the carrier body itself, while the processes c3) and c4) relate to the application of a (like) additional material.
  • coating processes known in the field of catalytic converters and the application processes described above for micro or nanotechnology can be used.
  • FIGS. 1 a perspective view of a layer 3 to the invention for an embodiment variant of the OF INVENTION ⁇ carrier body
  • FIG. 3 shows a first exemplary embodiment of a layer with a coating
  • FIG. 5 shows a third exemplary embodiment of a layer with a coating
  • FIG. 7 is a perspective view of another embodiment variant of a support body according to the invention in detail.
  • Fig. 1 shows in perspective a first embodiment of a layer 3, which is provided with a wave structure which limits at least partially flow paths 4.
  • the flow paths 4 have a length 19, wherein a substantially straight-line, parallel alignment of the flow paths 4 is provided in the illustrated embodiment variant.
  • a specifiable re- Holerenfall 20 are each passages 6 in the layer 3 forming corrugated noble ⁇ steel foil 17 is provided. As illustrated by means of the flow path 4 shown in the middle, these passages 6 permit a transgression into other flow paths 4, either only via the guide surfaces 21 pushed in upwards or downwards, or even through the adjacent openings through the layer 3.
  • the exhaust gas stream strikes the guide surface 21 arranged in the flow path 4, which narrows the minimum cross section of the flow path 4 significantly.
  • a large part of the partial exhaust gas stream located in the flow path 4 is deflected upward, at which point a (not shown here) fabric of metallic Drahtf ⁇ lamenten is preferably provided, which then filters and cleans the exhaust gas flowing therethrough.
  • the dynamic pressure builds up only as long as an alternative for the exhaust gas is created. This can be recognized by the arrows on the left, dashed lines.
  • the guide surface 11 does not completely close the flow path 4, so that there is also a side stream (dashed arrows on the right in Fig. 1) is possible.
  • FIG. 2 illustrates a variant embodiment of a carrier body 1, wherein a plurality of smooth and structured layers 3 are wound in an S-shape with one another and arranged in a housing 27.
  • the layers 3 are smooth Stainless steel foils 16 and corrugated stainless steel foils 17 are formed. Between the glat ⁇ th and corrugated stainless steel foil now form substantially parallel from zuein ⁇ other extending channels or flow paths. 4
  • the boundaries of the flow paths 4 through the stainless steel foils 16, 17 result in a total of the total support surface 7 or also called "GSA".
  • FIG. 3 now illustrates in a detail a first embodiment variant of a coating 2 which is formed on a layer 3.
  • the coating 2 has a total coating thickness 9 of at most 10 microns. It is formed with an outer boundary layer 11, which is directly in contact with the exhaust gas and has a boundary layer thickness 12 of at most 1 ⁇ m. In this surface boundary layer 11, substantially all noble metal catalysts 10 are arranged. Between the surface boundary layer 11 and the layer 3, a porous storage layer 13 is also provided.
  • This storage layer may, for example, with gamma-Al 2 O 3 (washcoat) or a mixture of gamma-Al 2 ⁇ 3 with CeO and other oxides may be formed, wherein the layer thickness is to be chosen correspondingly smaller.
  • Fig. 4 another exemplary embodiment of the coating 2 is shown, wherein the layer 3 is formed with a smooth stainless steel foil 16 having a corresponding proportion of aluminum.
  • a surface oxide 18 is formed by a corresponding thermal treatment.
  • the surface oxide 18 increases the surface roughness of the smooth stainless steel foil 16, so that the noble metal catalyst 10 can be permanently placed.
  • the noble metal catalysts 10 were listed directly on the layer 3.
  • the boundary layer thickness 12 of the surface boundary layer 11 ie in particular the layer of the coating in which the noble metal catalyst 10 is arranged
  • the entire coating thickness 9 to a few nanometers limited. It is preferred that the noble metal catalysts 10 are arranged evenly distributed in the coating section or on the layer surface 24.
  • a hole 22 with a large hole cross-section 23 is provided ⁇ . As a result, a flow exchange through the layer 3 itself is made possible.
  • Fig. 6 is shown schematically and as a detail of an embodiment of the flow path 4.
  • the carrier body is formed by an alternating arrangement of knitted fabrics 14 and a corrugated stainless steel foil 17.
  • the flow path 4 is designed with a minimum cross section 5 (hatched) of at least 0.5 mm. With regard to the determination of the minimum cross-section 5, the guide surfaces 21 projecting into the flow path 4 are not taken into account, but instead the entire cross-section is used at this point, as it exists in large sub-regions of the flow path.
  • the knitted fabrics 14 have wire filaments 15, which are designed, for example, with a thickness of 15 to 50 ⁇ m [micrometers].
  • the knitted fabrics advantageously have a weight per unit area of 200 to 1000 g / m 2 [grams per square meter] and a height between 0.1 and 0.5 mm [millimeters].
  • the individual wire filaments 15 are welded together, a corresponding or similar connection is advantageously also provided between the knitted fabric 14 and the corrugated stainless steel foil 17.
  • the noble metal catalyst 10 is provided for activating a catalytic conversion of by-passing pollutants in the exhaust gas.
  • Fig. 7 illustrates a further embodiment of a carrier body 1 in a perspective view and in detail.
  • the carrier body is in turn connected with corrugated layers 3 formed, between which a knitted fabric 14 is provided.
  • the layers 3 are provided with guide surfaces 21 for fluidic influencing of the exhaust gas, which usually flows through in the main flow direction 14 through the carrier body 1 (as well as entrained particles 29).
  • the smooth layer disposed therebetween comprises a composite material comprising a section of smooth stainless steel foil 16 and another section of knitted fabric 14.
  • the two components are advantageously connected to one another by joining technology, in particular by welding.
  • the smooth stainless steel foil 16 forms a coating section 8, that is, where the catalytically active material is provided there.
  • the knitted fabric 14 is designed without a corresponding coating. Both in the smooth stainless steel foil 16 and in the knit 14 further holes 22 or (not shown) passages may be provided.
  • Fig. 8 now illustrates a particularly preferred application of the carrier body described here as exhaust treatment unit 25 in a vehicle 26.
  • the exhaust gas generated in an internal combustion engine 30 is passed through a corresponding exhaust system 31, for example, several exhaust gas treatment units 25 flows through with such a carrier body before it is finally released cleaned to the environment.
  • such carrier bodies can also be used in stationary combustion power plants, working machines, handheld devices and the like.
  • the catalyst elements 32 are dispersedly distributed on a surface of the carrier body 1, the catalyst elements 32 having an average size 33 of advantageously less than 10 nm to have. They are with each other a distance 34 in the region larger than the size 33 of the catalyst element 32 is arranged.
  • FIG. 10 illustrates once again in another way the disperse arrangement of the catalyst elements 32 a mean distance 34 along the surface 35, which should be at least 3 micrometers.
  • the surface also has an average roughness R z of about 6 microns, which is formed here with a surface oxide 18 of a smooth stainless steel foil 16.
  • the roughness profile according to the invention now ensures a sufficient distance between the catalyst elements 32 to one another, so that even with the increased concentration of the catalyst elements 32 on the surface 35, a merger is avoided and efficient implementation of the exhaust gas pollutants is ensured.
  • additional advantages can be achieved also in view of the manufacturing cost of such a carrier body due to the reduced amount of the coating material.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Combustion & Propulsion (AREA)
  • Health & Medical Sciences (AREA)
  • Environmental & Geological Engineering (AREA)
  • Biomedical Technology (AREA)
  • Analytical Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Toxicology (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Catalysts (AREA)
  • Exhaust Gas After Treatment (AREA)

Abstract

Corps de support (1) avec une surface totale (7) présentant au moins une section de revêtement (8), avec un revêtement (2) à activation catalytique comprenant au moins un type d'éléments de catalyseurs (32) disposés de manière dispersée sur une surface (35) du corps de support (1), les éléments de catalyseur (32) présentant un espacement moyen (34) le long de la surface d'au moins 3 micromètres, la surface (35) ayant une profondeur rugueuse moyenne R<SUB>z</SUB> de 2 à 10 micromètres et le corps de support (1) présentant par rapport à un corps de support avec une surface lisse ou non revêtue (35) une augmentation de pertes de pression maximale de 25 %.
EP07724961A 2006-05-12 2007-05-08 Corps de support pour le traitement ultérieur des gaz d'échappement avec un ensemble disperseur-catalyseur Withdrawn EP2018221A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102006022364A DE102006022364A1 (de) 2006-05-12 2006-05-12 Trägerkörper zur Abgasnachbehandlung mit disperser Katalysatoranordnung
PCT/EP2007/004037 WO2007131665A1 (fr) 2006-05-12 2007-05-08 Corps de support pour le traitement ultérieur des gaz d'échappement avec un ensemble disperseur-catalyseur

Publications (1)

Publication Number Publication Date
EP2018221A1 true EP2018221A1 (fr) 2009-01-28

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EP07724961A Withdrawn EP2018221A1 (fr) 2006-05-12 2007-05-08 Corps de support pour le traitement ultérieur des gaz d'échappement avec un ensemble disperseur-catalyseur

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Country Link
US (1) US8182753B2 (fr)
EP (1) EP2018221A1 (fr)
JP (1) JP2009536873A (fr)
KR (1) KR101060986B1 (fr)
CN (1) CN101443121B (fr)
DE (1) DE102006022364A1 (fr)
RU (1) RU2408423C2 (fr)
TW (1) TW200742615A (fr)
WO (1) WO2007131665A1 (fr)

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DE102007042616A1 (de) * 2007-09-07 2009-03-12 Emitec Gesellschaft Für Emissionstechnologie Mbh Metallische Folie zur Herstellung von Wabenkörpern und daraus hergestellter Wabenkörper
DE102008062417A1 (de) * 2008-12-17 2010-07-01 Volkswagen Ag Abgasreinigung eines Abgasstroms einer Brennkraftmaschine
WO2014099592A1 (fr) * 2012-12-18 2014-06-26 Invista Technologies S.A.R.L. Procédés pour la production de cyanure d'hydrogène à l'aide d'un lit de catalyseur
US10451211B2 (en) * 2015-10-19 2019-10-22 United Technologies Corporation Radical-neutralizing coating for a lubricant system
DE102017218862A1 (de) 2017-10-23 2018-09-13 Audi Ag Verfahren und Vorrichtung zur Bauteilerkennung

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Also Published As

Publication number Publication date
JP2009536873A (ja) 2009-10-22
CN101443121A (zh) 2009-05-27
CN101443121B (zh) 2012-07-25
RU2408423C2 (ru) 2011-01-10
DE102006022364A1 (de) 2007-11-15
US20090104089A1 (en) 2009-04-23
US8182753B2 (en) 2012-05-22
KR101060986B1 (ko) 2011-08-31
RU2008148832A (ru) 2010-06-20
TW200742615A (en) 2007-11-16
WO2007131665A1 (fr) 2007-11-22
KR20090027629A (ko) 2009-03-17

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