US20090241514A1 - Catalytic converter for the treatment of combustion exhaust gases - Google Patents
Catalytic converter for the treatment of combustion exhaust gases Download PDFInfo
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- US20090241514A1 US20090241514A1 US12/333,087 US33308708A US2009241514A1 US 20090241514 A1 US20090241514 A1 US 20090241514A1 US 33308708 A US33308708 A US 33308708A US 2009241514 A1 US2009241514 A1 US 2009241514A1
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- 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
- F01N3/01—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust by means of electric or electrostatic separators
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- 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
- B01D53/32—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 by electrical effects other than those provided for in group B01D61/00
- B01D53/326—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 by electrical effects other than those provided for in group B01D61/00 in electrochemical cells
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- 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
- B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
- B01D53/86—Catalytic processes
- B01D53/8621—Removing nitrogen compounds
- B01D53/8625—Nitrogen oxides
- B01D53/8628—Processes characterised by a specific catalyst
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- B—PERFORMING OPERATIONS; TRANSPORTING
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- 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
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- 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
- F01N3/0892—Electric or magnetic treatment, e.g. dissociation of noxious components
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- 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
- F01N3/18—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 methods of operation; Control
- F01N3/20—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 methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
- F01N3/2006—Periodically heating or cooling catalytic reactors, e.g. at cold starting or overheating
- F01N3/2013—Periodically heating or cooling catalytic reactors, e.g. at cold starting or overheating using electric or magnetic heating means
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- 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
- F01N3/18—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 methods of operation; Control
- F01N3/20—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 methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
- F01N3/2006—Periodically heating or cooling catalytic reactors, e.g. at cold starting or overheating
- F01N3/2013—Periodically heating or cooling catalytic reactors, e.g. at cold starting or overheating using electric or magnetic heating means
- F01N3/2026—Periodically heating or cooling catalytic reactors, e.g. at cold starting or overheating using electric or magnetic heating means directly electrifying the catalyst substrate, i.e. heating the electrically conductive catalyst substrate by joule effect
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- 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
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- 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
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- 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
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- 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
- B01D2255/2061—Yttrium
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2255/00—Catalysts
- B01D2255/20—Metals or compounds thereof
- B01D2255/207—Transition metals
- B01D2255/20715—Zirconium
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2255/00—Catalysts
- B01D2255/40—Mixed oxides
- B01D2255/402—Perovskites
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2255/00—Catalysts
- B01D2255/40—Mixed oxides
- B01D2255/405—Spinels
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2255/00—Catalysts
- B01D2255/90—Physical characteristics of catalysts
- B01D2255/902—Multilayered catalyst
- B01D2255/9027—More than three layers
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2257/00—Components to be removed
- B01D2257/40—Nitrogen compounds
- B01D2257/404—Nitrogen oxides other than dinitrogen oxide
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- 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
- B01D53/9404—Removing only nitrogen compounds
- B01D53/9409—Nitrogen oxides
- B01D53/9413—Processes characterised by a specific catalyst
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- 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
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- 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
- F01N2330/04—Methods of manufacturing
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- 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
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- 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
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T29/00—Metal working
- Y10T29/49—Method of mechanical manufacture
- Y10T29/49345—Catalytic device making
Definitions
- the present invention relates to a catalytic converter for the treatment of combustion exhaust gases, a method for its production, and a method for its use.
- Catalytic converters are used for the aftertreatment of combustion exhaust gases, which are produced in industrial processes such as in the combustion of fossil fuels in the engine, for instance. These catalytic converters are used to eliminate gaseous components of the combustion exhaust gases.
- nitrogen oxide adsorption catalysts are used for this purpose, which store nitrogen oxides contained in a combustion exhaust gas at least temporarily and release them again during a subsequent periodic regeneration process.
- Another possibility consists of the utilization of exhaust gas aftertreatment devices based on what is known as SCR technology (selective catalytic reduction), in which chemical reducing agents such as ammonia can be mixed with the exhaust gas to be purified, and the nitrogen oxides eliminated.
- This catalytic converter includes a catalytically active layer on the basis of a mixed oxide, and an electrochemical cell, which is designed on the basis of zirconium dioxide as solid electrolyte.
- this object may be achieved by a catalytic converter and by a method for its production having the characterizing features described herein.
- the catalytic converter includes a planar first electrode, which is positioned so as to be in physical contact with a layer that is made of a catalytically active material suitable for converting gas components of the combustion exhaust gas.
- An electric pumping voltage is able to be applied to this planar first electrode.
- the oxygen produced in the decomposition of, e.g., nitrogen oxide, in the form of 02 ions is able to be electrochemically removed from the region of the layer that is made of a catalytically active material suitable for converting gas components of the combustion exhaust gas.
- This achieves a low oxygen concentration in the region of this layer, and the catalytically active material is effectively protected against a deactivation caused by oxygen.
- an additional electrode which acts as counter-electrode to the first electrode, forms an electrochemical cell together with the first electrode and has an open, porous design. In this way, it is easy for the oxygen released in the decomposition of nitrogen oxides to be carried off on the anode side through the open-pored structure of the electrode.
- the catalytic layer containing the catalytically active material has a wavy structure.
- Such a structure can be produced, for instance, by a brief lateral elongation of a composite in the form of a green ceramic body, the composite body being made up of the catalytic layer, the first and the second electrode, and a solid electrolyte.
- the wavy structure has the advantage of greater stability while simultaneously increasing the reactive surface, available for the conversion of exhaust-gas components, of the catalytic converter of the present invention.
- a composite made up of a solid electrolyte, the first and the second electrode and a catalytic converter layer is rolled up parallel to a longitudinal axis of the green body, so that a rotationally symmetric body is formed. This makes it possible to produce the final three-dimensional form of the catalytic converter in a simple manner.
- a plurality of first electrodes and a plurality of second electrodes are provided in the region of the catalytic layer, which jointly form an interdigital structure.
- This interdigital structure allows simple, joint contacting of all first electrodes and of all second electrodes in each case, via a shared electric supply line, e.g., at the end face on the produced rotationally symmetric catalytic converter body.
- FIG. 1 shows a schematic, sectional view of a catalytic converter for the treatment of combustion exhaust gases according to a first exemplary embodiment of the present invention.
- FIG. 2 shows a schematic, sectional view of a catalytic converter for the treatment of combustion exhaust gases according to a second exemplary embodiment of the present invention.
- FIG. 3 shows a schematic, sectional view of the catalytic converter shown in FIG. 2 , the catalytic converter including a wavy structure.
- FIG. 4 shows a schematic, sectional view of a catalytic converter according to one of the aforementioned exemplary embodiments, in the form of a rotationally symmetric catalyst body.
- FIG. 1 schematically shows a catalytic converter according to the present invention for the treatment of combustion exhaust gases. It is preferably used for the conversion of gaseous or solid pollutant components of the combustion exhaust gases, in particular for the conversion of oxygen-containing, gaseous components.
- Catalytic converter 10 has a catalytic layer 12 of a catalytically active material and is preferably covered by a solid electrolyte layer 14 . Suitable as solid electrolyte is, for example, zirconium dioxide partially or fully stabilized by Bi 2 O 3 , or Gd-doped CeO 2 .
- one or more first electrodes 16 is/are positioned on a further large surface of catalytic layer 12 .
- the at least one first electrode 16 forms an electrochemical cell together with at least one second electrode 18 , which preferably is positioned on the side of solid electrolyte layer 14 facing away from layer 12 .
- Electrodes 16 , 18 are produced from, for example, nickel, silver, platinum or palladium, or from alloys of these elements.
- Suitable as catalytically active components of catalytic layer 12 are, for instance, metallic components such as rhodium, palladium, platinum, iridium or nickel, or alloys thereof.
- these metallic components may be present as nanoscale dispersion on the surface of zirconium-dioxide particles.
- mixed oxides such as specifically spinels of the general formula A 2 BO 4 and perovskites of the general formula ABO 3 , are suitable as catalytically active components of catalytic layer 12 , in which A refers to, e.g., elements of the lanthanides, actinides, the alkali metals, alkaline-earth metals, or for yttrium, and B refers to, e.g., copper, iron, nickel or cobalt.
- A- or B-positions of the mentioned compounds can also be occupied by several of the aforementioned elements, possibly also in a non-stoichiometric manner.
- perovskites in which the A-position is occupied by the elements of lanthanum or strontium, and the B-positions are occupied by at least one of the elements of iron, cobalt or nickel.
- Exemplary representatives of these suitable perovskites are (La 0,9 Sr 0,1 ) (Fe 0,9 Ni 0,1 )O 3 , (La 0,9 Sr 0,1 )FeO 3 or La 0,5 Sr 0,5 CoO 3 ; the LaNiO 3 compound is rather unsuitable for technical reasons.
- a foil of a ceramic solid electrolyte material is preferably provided in the form of a green body, which is then printed over on a first large surface with at least one first electrode 16 , and on an opposite-lying additional large surface with at least one additional electrode 18 .
- catalytic layer 12 is deposited on the large surface of solid electrolyte layer 14 provided with the at least one first electrode 16 .
- electrodes 16 , 18 are applied in the form of an interdigital structure.
- electrodes 16 , 18 are designed in the form of, e.g., a plurality of metallic, in particular parallel strips, for instance, the first electrodes 16 being guided right into the immediate vicinity of a first end face of the produced layer composite; first electrodes 16 have a minimum distance of I to 4 mm from the opposite lying front end of the layer composite.
- the further electrodes 18 have an oppositely directed orientation; they maintain a minimum distance of 1 to 4 mm from the first end face of the layer composite and essentially abut directly against the opposite-lying end face of the layer composite.
- This measure allows an especially simple contacting of the first and additional electrodes 16 , 18 , in that an exclusive contacting of first electrode 16 takes place at the first end face of the layer composite, and an exclusive contacting of additional electrodes 18 takes place at the end face lying opposite.
- the layer composite produced in this manner is subjected to a heat treatment, specifically a sintering treatment, during which the catalytic converter structure shown in FIG. 1 is formed.
- FIG. 2 Another exemplary embodiment of a catalytic converter according to the present invention is shown in FIG. 2 .
- Matching reference numerals indicate the same module components as in the previous figures.
- the composite body made up of catalytic layer 12 , solid electrolyte layer 14 , and electrodes 16 , 18 is laminated together with an additional composite body of the same type, both composite bodies having shared additional electrodes 18 .
- This overall structure, made up of two composite systems is then subjected to the heat or sintering treatment.
- the result is the catalytic converter according to a second exemplary embodiment shown in FIG. 2 . If the overall structure made up of two composite systems is subjected to a drawing process prior to the heat or sintering treatment, then a catalytic converter according to a third exemplary embodiment, as shown in FIG. 3 , results after the sintering.
- the catalytic converters according to the first to third exemplary embodiments may be rolled up about an axis of rotation that is parallel to a longitudinal axis of the composite system, so that in particular, a cylindrical, three-dimensional catalytic converter body 40 is produced.
- the final heat or sintering treatment for example, it is provided with electrode contacts by partially grinding the resulting, in particular, cylindrical catalytic converter body 40 at the front end, for example, in each case, and by providing it at the front end with a network of a nickel or silver wire in order to establish contact to first or second electrodes 16 , 18 .
- the method of using catalytic converter 10 , 40 is based on the fact that in conventional catalytic converters according to the related art, the oxygen released during the thermal decomposition of nitrogen oxides, for example, deposits at the surface of the catalytic converter material and thereby reduces the catalytic activity.
- a voltage is applied to electrodes 16 , 18 of catalytic converter 10 , 40 during operation, which, as pumping voltage of sufficient magnitude, causes oxygen in the form of oxygen ions to be transported from the at least one first electrode 16 to the at least one further electrode 18 . If an exhaust gas atmosphere is present at the large surface formed by catalytic layer 12 , then the surface of catalytic layer 12 becomes poorer in gaseous oxygen, thereby facilitating the decomposition of oxygen-containing components of a combustion exhaust gas.
- the at least one additional electrode 18 acting as anode has an open-pore design, so that the oxygen pumped thereto is able to escape in a simple manner.
- the afore-described catalytic converter according to the exemplary embodiments described is particularly suitable for converting oxygen-containing gas components of a combustion exhaust gas, such as nitrogen oxides or sulfur oxides. It may be utilized both for the exhaust gas aftertreatment of combustion exhaust gases of combustion engines and for the exhaust gas treatment of heating systems or for power plant applications.
- a combustion exhaust gas such as nitrogen oxides or sulfur oxides.
Abstract
A catalytic converter for the treatment of combustion exhaust gases includes a first large surface, which is exposed to the exhaust gas to be purified and which has a layer of a catalytically active material suitable for converting gas components, and a planar first electrode which is in physical contact with the layer made of a catalytically active material suitable for converting gas components, and which is able to receive an electric pumping voltage.
Description
- The present invention relates to a catalytic converter for the treatment of combustion exhaust gases, a method for its production, and a method for its use.
- Catalytic converters are used for the aftertreatment of combustion exhaust gases, which are produced in industrial processes such as in the combustion of fossil fuels in the engine, for instance. These catalytic converters are used to eliminate gaseous components of the combustion exhaust gases.
- The elimination of nitrogen oxides from exhaust gases of combustion engines is becoming ever more important. Among others, nitrogen oxide adsorption catalysts are used for this purpose, which store nitrogen oxides contained in a combustion exhaust gas at least temporarily and release them again during a subsequent periodic regeneration process. Another possibility consists of the utilization of exhaust gas aftertreatment devices based on what is known as SCR technology (selective catalytic reduction), in which chemical reducing agents such as ammonia can be mixed with the exhaust gas to be purified, and the nitrogen oxides eliminated.
- In order to optimize the elimination rate of such a denitrification catalyst, it is known from JP 07-275714, for instance, to convert nitrogen oxides into nitrogen and oxygen catalytically, the produced oxygen at the cathode of an electrochemical cell being converted into oxygen ions and removed from the reaction region. This makes it possible to prevent a reverse reaction of nitrogen with oxygen into nitrogen oxides. This catalytic converter includes a catalytically active layer on the basis of a mixed oxide, and an electrochemical cell, which is designed on the basis of zirconium dioxide as solid electrolyte.
- It is an object of the present invention to provide a catalytic converter for the treatment of combustion exhaust gases, which is able to remove nitrogen oxides from combustion exhaust gases in an efficient manner.
- In an advantageous manner, this object may be achieved by a catalytic converter and by a method for its production having the characterizing features described herein. In particular, this is based on the fact that the catalytic converter includes a planar first electrode, which is positioned so as to be in physical contact with a layer that is made of a catalytically active material suitable for converting gas components of the combustion exhaust gas. An electric pumping voltage is able to be applied to this planar first electrode.
- In this way, the oxygen produced in the decomposition of, e.g., nitrogen oxide, in the form of 02 ions is able to be electrochemically removed from the region of the layer that is made of a catalytically active material suitable for converting gas components of the combustion exhaust gas. This achieves a low oxygen concentration in the region of this layer, and the catalytically active material is effectively protected against a deactivation caused by oxygen.
- Further advantageous developments of the present catalytic converter are described herein.
- For instance, it is advantageous if an additional electrode, which acts as counter-electrode to the first electrode, forms an electrochemical cell together with the first electrode and has an open, porous design. In this way, it is easy for the oxygen released in the decomposition of nitrogen oxides to be carried off on the anode side through the open-pored structure of the electrode.
- Furthermore, it is advantageous if the catalytic layer containing the catalytically active material has a wavy structure. Such a structure can be produced, for instance, by a brief lateral elongation of a composite in the form of a green ceramic body, the composite body being made up of the catalytic layer, the first and the second electrode, and a solid electrolyte. The wavy structure has the advantage of greater stability while simultaneously increasing the reactive surface, available for the conversion of exhaust-gas components, of the catalytic converter of the present invention.
- According to one advantageous embodiment of the present invention, following a brief lateral elongation, a composite made up of a solid electrolyte, the first and the second electrode and a catalytic converter layer, is rolled up parallel to a longitudinal axis of the green body, so that a rotationally symmetric body is formed. This makes it possible to produce the final three-dimensional form of the catalytic converter in a simple manner.
- According to one additional advantageous embodiment of the present invention, a plurality of first electrodes and a plurality of second electrodes are provided in the region of the catalytic layer, which jointly form an interdigital structure. This interdigital structure allows simple, joint contacting of all first electrodes and of all second electrodes in each case, via a shared electric supply line, e.g., at the end face on the produced rotationally symmetric catalytic converter body.
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FIG. 1 shows a schematic, sectional view of a catalytic converter for the treatment of combustion exhaust gases according to a first exemplary embodiment of the present invention. -
FIG. 2 shows a schematic, sectional view of a catalytic converter for the treatment of combustion exhaust gases according to a second exemplary embodiment of the present invention. -
FIG. 3 shows a schematic, sectional view of the catalytic converter shown inFIG. 2 , the catalytic converter including a wavy structure. -
FIG. 4 shows a schematic, sectional view of a catalytic converter according to one of the aforementioned exemplary embodiments, in the form of a rotationally symmetric catalyst body. -
FIG. 1 schematically shows a catalytic converter according to the present invention for the treatment of combustion exhaust gases. It is preferably used for the conversion of gaseous or solid pollutant components of the combustion exhaust gases, in particular for the conversion of oxygen-containing, gaseous components.Catalytic converter 10 has acatalytic layer 12 of a catalytically active material and is preferably covered by asolid electrolyte layer 14. Suitable as solid electrolyte is, for example, zirconium dioxide partially or fully stabilized by Bi2O3, or Gd-doped CeO2. Furthermore, one or morefirst electrodes 16 is/are positioned on a further large surface ofcatalytic layer 12. The at least onefirst electrode 16 forms an electrochemical cell together with at least onesecond electrode 18, which preferably is positioned on the side ofsolid electrolyte layer 14 facing away fromlayer 12.Electrodes - Suitable as catalytically active components of
catalytic layer 12 are, for instance, metallic components such as rhodium, palladium, platinum, iridium or nickel, or alloys thereof. For example, these metallic components may be present as nanoscale dispersion on the surface of zirconium-dioxide particles. Furthermore, mixed oxides, such as specifically spinels of the general formula A2BO4 and perovskites of the general formula ABO3, are suitable as catalytically active components ofcatalytic layer 12, in which A refers to, e.g., elements of the lanthanides, actinides, the alkali metals, alkaline-earth metals, or for yttrium, and B refers to, e.g., copper, iron, nickel or cobalt. The A- or B-positions of the mentioned compounds can also be occupied by several of the aforementioned elements, possibly also in a non-stoichiometric manner. Especially preferred are perovskites in which the A-position is occupied by the elements of lanthanum or strontium, and the B-positions are occupied by at least one of the elements of iron, cobalt or nickel. Exemplary representatives of these suitable perovskites are (La0,9Sr0,1) (Fe0,9Ni0,1)O3, (La0,9Sr0,1)FeO3 or La0,5Sr0,5CoO3; the LaNiO3 compound is rather unsuitable for technical reasons. - To produce a catalytic converter according to the first exemplary embodiment shown in
FIG. 1 , as an initial step, a foil of a ceramic solid electrolyte material is preferably provided in the form of a green body, which is then printed over on a first large surface with at least onefirst electrode 16, and on an opposite-lying additional large surface with at least oneadditional electrode 18. Then,catalytic layer 12 is deposited on the large surface ofsolid electrolyte layer 14 provided with the at least onefirst electrode 16. - It is preferred if
electrodes electrodes first electrodes 16 being guided right into the immediate vicinity of a first end face of the produced layer composite;first electrodes 16 have a minimum distance of I to 4 mm from the opposite lying front end of the layer composite. Thefurther electrodes 18 have an oppositely directed orientation; they maintain a minimum distance of 1 to 4 mm from the first end face of the layer composite and essentially abut directly against the opposite-lying end face of the layer composite. This measure allows an especially simple contacting of the first andadditional electrodes first electrode 16 takes place at the first end face of the layer composite, and an exclusive contacting ofadditional electrodes 18 takes place at the end face lying opposite. The layer composite produced in this manner is subjected to a heat treatment, specifically a sintering treatment, during which the catalytic converter structure shown inFIG. 1 is formed. - However, prior to the heat treatment, what is known as a drawing process can optionally be implemented, during which the composite body made up of
catalytic layer 12,solid electrolyte layer 14 andelectrodes - Another exemplary embodiment of a catalytic converter according to the present invention is shown in
FIG. 2 . Matching reference numerals indicate the same module components as in the previous figures. Prior to the heat or sintering treatment, the composite body made up ofcatalytic layer 12,solid electrolyte layer 14, andelectrodes additional electrodes 18. This overall structure, made up of two composite systems, is then subjected to the heat or sintering treatment. The result is the catalytic converter according to a second exemplary embodiment shown inFIG. 2 . If the overall structure made up of two composite systems is subjected to a drawing process prior to the heat or sintering treatment, then a catalytic converter according to a third exemplary embodiment, as shown inFIG. 3 , results after the sintering. - Furthermore, prior to the final heat or sintering treatment, the catalytic converters according to the first to third exemplary embodiments may be rolled up about an axis of rotation that is parallel to a longitudinal axis of the composite system, so that in particular, a cylindrical, three-dimensional
catalytic converter body 40 is produced. Following the final heat or sintering treatment, for example, it is provided with electrode contacts by partially grinding the resulting, in particular, cylindricalcatalytic converter body 40 at the front end, for example, in each case, and by providing it at the front end with a network of a nickel or silver wire in order to establish contact to first orsecond electrodes - The method of using
catalytic converter electrodes catalytic converter first electrode 16 to the at least onefurther electrode 18. If an exhaust gas atmosphere is present at the large surface formed bycatalytic layer 12, then the surface ofcatalytic layer 12 becomes poorer in gaseous oxygen, thereby facilitating the decomposition of oxygen-containing components of a combustion exhaust gas. - In addition, a deactivation of the catalytically active components provided in
catalytic layer 12 is prevented. It is advantageous in this context if the at least oneadditional electrode 18 acting as anode has an open-pore design, so that the oxygen pumped thereto is able to escape in a simple manner. - The afore-described catalytic converter according to the exemplary embodiments described is particularly suitable for converting oxygen-containing gas components of a combustion exhaust gas, such as nitrogen oxides or sulfur oxides. It may be utilized both for the exhaust gas aftertreatment of combustion exhaust gases of combustion engines and for the exhaust gas treatment of heating systems or for power plant applications.
Claims (12)
1. A catalytic converter for treatment of combustion exhaust gases, comprising:
a first large surface exposed to the exhaust gases to be purified, the first large surface including a layer made of a catalytically active material suitable for converting gas components; and
a planar first electrode situated so as to be in physical contact with the layer made of the catalytically active material suitable for converting gas components, the planar first electrode configured to receive an electric pumping voltage.
2. The catalytic converter according to claim 1 , further comprising:
a solid electrolyte layer in physical contact with at least one of the first electrode and an additional electrode, the first electrode and the additional electrode forming an electrochemical cell.
3. The catalytic converter according to claim 1 , wherein the additional electrode acts as anode and includes an open-pore design.
4. The catalytic converter according to claim 2 , wherein the solid electrolyte layer contains zirconium dioxide.
5. The catalytic converter according to claim 1 , wherein a catalytic converter material includes one of a spinel and a perovskite.
6. The catalytic converter according to claim 5 , wherein the perovskite is a compound of general formula ABO3, and the spinel is a compound of general formula A2BO4, wherein A includes one of yttrium and at least one of lanthanides, actinides, alkali metals, earth alkali metals, and mixtures thereof, and B includes at least one of copper, iron, cobalt, nickel and mixtures thereof.
7. The catalytic converter according to claim 1 , wherein the layer of the catalytically active material suitable for converting gas components includes a wavy structure.
8. The catalytic converter according to claim 2 , further comprising:
a plurality of the first electrode and a plurality of additional electrode, configured to jointly form an interdigital structure.
9. A method for producing a catalytic converter for treatment of combustion exhaust gases, wherein the catalytic converter includes a first large surface exposed to the exhaust gases to be purified, the first large surface including a layer made of a catalytically active material suitable for converting gas components; and a planar first electrode situated so as to be in physical contact with the layer made of the catalytically active material suitable for converting gas components, the planar first electrode configured to receive an electric pumping voltage, the method comprising:
providing a ceramic green body foil including a solid electrolyte material with the first electrode on the first large surface, and with the layer containing catalytically active material suitable for converting gas components, and with a second electrode on a second large surface; and
laterally elongating the ceramic green body foil, the first electrode, the second electrode, and the layer containing catalytically active material suitable for converting gas components, thereby obtaining a wavy structure.
10. The method according to claim 9 , further comprising:
after the lateral elongating, rolling up the ceramic green body foil, the first electrode, the second electrode, and the layer containing catalytically active material suitable for converting gas components parallel to a longitudinal axis of the green body foil, thereby producing a rotationally symmetric body.
11. The method according to claim 9 , further comprising:
sintering the ceramic green body foil, the first electrode, the second electrode, and the layer containing catalytically active material suitable for converting gas components.
12. A method of using a catalytic converter for treatment of combustion exhaust gases, wherein the catalytic converter includes a first large surface exposed to the exhaust gases to be purified, the first large surface including a layer made of a catalytically active material suitable for converting gas components; and a planar first electrode situated so as to be in physical contact with the layer made of the catalytically active material suitable for converting gas components, the planar first electrode configured to receive an electric pumping voltage, the method comprising:
removing oxygen-containing components of a gas mixture.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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DE102007062249.1 | 2007-12-21 | ||
DE102007062249A DE102007062249A1 (en) | 2007-12-21 | 2007-12-21 | Catalyst for the treatment of combustion exhaust gases |
Publications (1)
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US20090241514A1 true US20090241514A1 (en) | 2009-10-01 |
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ID=40545845
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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US12/333,087 Abandoned US20090241514A1 (en) | 2007-12-21 | 2008-12-11 | Catalytic converter for the treatment of combustion exhaust gases |
Country Status (3)
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US (1) | US20090241514A1 (en) |
EP (1) | EP2072770A3 (en) |
DE (1) | DE102007062249A1 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
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US20110011065A1 (en) * | 2008-05-30 | 2011-01-20 | Deutz Aktiengesellschaft | High-efficiency scr catalytic converter |
JP2016013545A (en) * | 2014-07-02 | 2016-01-28 | 黄 大勇 | Electrochemical double cell plate and device for controlling emission of exhaust gas |
US11110432B2 (en) * | 2019-12-09 | 2021-09-07 | Toyota Motor Engineering And Manufacturing North America, Inc. | Multi-transition metal doped copper-cobalt spinel catalyst material for NOx decomposition |
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FR2939696B1 (en) * | 2008-12-17 | 2015-12-04 | Saint Gobain Ct Recherches | PURIFICATION STRUCTURE INCORPORATING A POLARIZED ELECTROCHEMICAL CATALYSIS SYSTEM |
DE102010030394A1 (en) * | 2010-06-23 | 2011-12-29 | Robert Bosch Gmbh | Electrochemical nitric oxide catalyst |
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US20080199654A1 (en) * | 2005-09-09 | 2008-08-21 | Emitec Gesellschaft Fur Emissionstechnologie Mbh | Method for Producing an Annular Honeycomb Body, and Annular Honeycomb Body |
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SE404065B (en) * | 1972-11-30 | 1978-09-18 | Atomic Energy Authority Uk | APPARATUS FOR CATALYTIC CLEANING OF EXHAUST AND CATALYST |
JPH03224634A (en) * | 1990-01-30 | 1991-10-03 | Cataler Kogyo Kk | Catalyst for decomposition of ozone fitted with heater |
DE69027929T2 (en) * | 1990-10-10 | 1997-03-06 | Constantin G Vayenas | Use of metal solid electrolyte catalysts |
EP0566071B1 (en) * | 1992-04-14 | 1997-07-02 | Kabushiki Kaisha Toyota Chuo Kenkyusho | Method for reducing nitrogen oxides |
US5401372A (en) * | 1993-04-26 | 1995-03-28 | Ceramatec, Inc. | Electrochemical catalytic reduction cell for the reduction of NOx in an O2 -containing exhaust emission |
JPH07275714A (en) | 1994-04-11 | 1995-10-24 | Toray Ind Inc | Nox removing device |
JP2636193B2 (en) * | 1994-12-14 | 1997-07-30 | 工業技術院長 | Exhaust gas treatment method |
DE19900967A1 (en) * | 1999-01-13 | 2000-07-20 | Volkswagen Ag | Device for cleaning the exhaust gas of an internal combustion engine |
DE19904068A1 (en) * | 1999-02-02 | 2000-08-03 | Volkswagen Ag | Device for cleaning the exhaust gas of an internal combustion engine |
JP3657542B2 (en) * | 2001-07-24 | 2005-06-08 | 独立行政法人産業技術総合研究所 | Chemical reactor |
JP2007014873A (en) * | 2005-07-07 | 2007-01-25 | Honda Motor Co Ltd | Apparatus for removing particle substance |
-
2007
- 2007-12-21 DE DE102007062249A patent/DE102007062249A1/en not_active Withdrawn
-
2008
- 2008-10-24 EP EP08105658A patent/EP2072770A3/en not_active Withdrawn
- 2008-12-11 US US12/333,087 patent/US20090241514A1/en not_active Abandoned
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
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US20080199654A1 (en) * | 2005-09-09 | 2008-08-21 | Emitec Gesellschaft Fur Emissionstechnologie Mbh | Method for Producing an Annular Honeycomb Body, and Annular Honeycomb Body |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20110011065A1 (en) * | 2008-05-30 | 2011-01-20 | Deutz Aktiengesellschaft | High-efficiency scr catalytic converter |
US8484954B2 (en) * | 2008-05-30 | 2013-07-16 | Deutz Aktiengesellschaft | High-efficiency SCR catalytic converter |
JP2016013545A (en) * | 2014-07-02 | 2016-01-28 | 黄 大勇 | Electrochemical double cell plate and device for controlling emission of exhaust gas |
US11110432B2 (en) * | 2019-12-09 | 2021-09-07 | Toyota Motor Engineering And Manufacturing North America, Inc. | Multi-transition metal doped copper-cobalt spinel catalyst material for NOx decomposition |
Also Published As
Publication number | Publication date |
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EP2072770A3 (en) | 2010-04-07 |
EP2072770A2 (en) | 2009-06-24 |
DE102007062249A1 (en) | 2009-06-25 |
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