WO1996001142A1 - Catalyseur hybride de gaz d'echappement - Google Patents

Catalyseur hybride de gaz d'echappement Download PDF

Info

Publication number
WO1996001142A1
WO1996001142A1 PCT/GB1995/001499 GB9501499W WO9601142A1 WO 1996001142 A1 WO1996001142 A1 WO 1996001142A1 GB 9501499 W GB9501499 W GB 9501499W WO 9601142 A1 WO9601142 A1 WO 9601142A1
Authority
WO
WIPO (PCT)
Prior art keywords
catalyst
hybrid
lean
exhaust gas
engine
Prior art date
Application number
PCT/GB1995/001499
Other languages
English (en)
Inventor
Haren Sakarlal Gandhi
Jeffrey Scott Hepburn
Original Assignee
Ford Motor Company Limited
Ford Werke Ag
Ford France S.A.
Ford Motor Company Of Canada Ltd.
Ford Motor Company
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 Ford Motor Company Limited, Ford Werke Ag, Ford France S.A., Ford Motor Company Of Canada Ltd., Ford Motor Company filed Critical Ford Motor Company Limited
Priority to AU27491/95A priority Critical patent/AU2749195A/en
Publication of WO1996001142A1 publication Critical patent/WO1996001142A1/fr

Links

Classifications

    • 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
    • B01D53/9404—Removing only nitrogen compounds
    • B01D53/9409—Nitrogen oxides
    • 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
    • B01D53/9459—Removing one or more of nitrogen oxides, carbon monoxide, or hydrocarbons by multiple successive catalytic functions; systems with more than one different function, e.g. zone coated catalysts
    • B01D53/9463—Removing one or more of nitrogen oxides, carbon monoxide, or hydrocarbons by multiple successive catalytic functions; systems with more than one different function, e.g. zone coated catalysts with catalysts positioned on one brick
    • B01D53/9468—Removing one or more of nitrogen oxides, carbon monoxide, or hydrocarbons by multiple successive catalytic functions; systems with more than one different function, e.g. zone coated catalysts with catalysts positioned on one brick in different layers
    • 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
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/02—Impregnation, coating or precipitation
    • B01J37/024—Multiple impregnation or coating
    • B01J37/0244—Coatings comprising several layers
    • 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
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/02—Impregnation, coating or precipitation
    • B01J37/024—Multiple impregnation or coating
    • B01J37/0246—Coatings comprising a zeolite
    • 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
    • B01D2255/1021—Platinum
    • 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
    • B01D2255/1023—Palladium
    • 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
    • B01D2255/1025—Rhodium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/20—Metals or compounds thereof
    • B01D2255/204—Alkaline earth metals
    • B01D2255/2042—Barium
    • 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
    • B01D2255/2063—Lanthanum
    • 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
    • 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
    • B01D2255/20761—Copper
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/50—Zeolites
    • B01D2255/504—ZSM 5 zeolites
    • 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

  • This invention relates to a hybrid exhaust gas catalyst, and more particularly to a catalyst for removing nitrogen oxides, hydrocarbons and carbon monoxide during engine operation utilising both stoichiometric and lean (oxygen rich) air/fuel combustion ratios.
  • TWCs three-way catalysts
  • HC, CO, and NO ⁇ three constituents
  • conventional three-way catalysts are restricted to operation in a very narrow window of A/F ratio around the stoichiometric point.
  • A/F ratios which are very near to the stoichiometric value.
  • Lean-burn engines operate at a substantially higher A/F ratios than stoichiometric engines, i.e., greater than about 14.7, more generally between about 19 and 27.
  • a dedicated lean-burn vehicle is projected to employ lean-burn operation during all driving modes except for full acceleration.
  • Another approach is to operate in the lean-burn mode only during idle, deceleration and select cruise modes.
  • lean-burn catalysts are those based on transition metal exchanged zeolites. Such lean-burn catalysts convert the nitrogen oxides (NO ⁇ ) by means of selective reduction by hydrocarbons present in lean-burn exhaust gases.
  • One such catalyst is disclosed in U.S. Patent 5,155,077 to Montreuil et al. entitled "Catalyst for Purification of Lean-Burn Engine Exhaust Gas”. It discloses as a catalyst a dual-phase zeolite having a transition containing zeolite phase and a metal containing oxide phase.
  • LNC lean N0 ⁇ catalyst
  • the present invention surprisingly has been found to overcome such deficiencies by providing a hybrid TWC/LNC catalyst which avoids the problem of delayed light-off of the series TWC during cold start of the engine. Further, this hybrid catalyst is more compact than such series systems and as such provides for relative ease of packaging compared to the series approach.
  • This invention is an hybrid catalyst for purification of stoichiometric/lean-burn engine exhaust gas.
  • the hybrid catalyst comprises a first catalyst consisting of a catalytic material capable of reducing nitrogen oxides (NO ⁇ v under lean-burn engine conditions, and a second catalyst consisting of a three-way catalyst.
  • the catalytic material may be an intimate mixture of the first catalyst and the second catalyst or a layered combination of them.
  • the layered combination is employed, with the first catalyst being layered on the second catalyst which is carried on a substrate, like cordierite.
  • the catalysts would be applied in washcoats.
  • the first catalyst preferably is transition metal exchanged high-silica zeolite, more preferably being copper-exchanged high silica ZSM5 and the three-way catalyst preferably comprises a noble metal being, most preferably, palladium.
  • the invention comprises a method of purifying such exhaust gas employing the hybrid catalyst disclosed above.
  • Fig. 1 is a graph showing the NO ⁇ conversion for an embodiment of the hybrid LNC/TWC of the present invention as compared to a conventional TWC as a function of A/F;
  • Fig. 2 is a graph showing cold start hydrocarbon conversion efficiency for a comparative series LNC + TWC catalyst as compared to an embodiment of a hybrid LNC/TWC as in the present invention.
  • the catalyst of this invention comprises a hybrid of two catalysts, a first catalyst which is a lean N0 ⁇ catalyst (LNC) which is capable of selectively reducing NO ⁇ with hydrocarbons in the presence of excess oxygen and a second catalyst which is a three-way catalyst (TWC) .
  • LNC lean N0 ⁇ catalyst
  • TWC three-way catalyst
  • the first catalyst functions primarily as a lean-burn conversion catalyst
  • the second catalyst functioning primarily as a stoichiometric conversion catalyst.
  • Each is however capable of converting some of the other exhaust gas components to a lesser extent.
  • the invention hybrid catalyst may be in the form of an intimate mixture of the first catalyst and the second catalyst, or in the form of a combination of layers of these two catalysts.
  • the hybrid catalyst invention comprises a layered combination of the TWC and the LNC, where the LNC is overcoated on the TWC (which is carried on a substrate like a cordierite monolith) . Locating the LNC in the outermost layer (such that the exhaust gas contacts the LNC first) maximises the availability of hydrocarbons for lean NO ⁇ catalysis, since the LNC has minimal oxidising activity.
  • the exhaust gas subsequently would be expected to diffuse through the LNC to contact the TWC for further catalytic activity toward the exhaust gas.
  • the catalysts are employed in the invention as part of a washcoat comprising these catalyst materials, individually in separate washcoat layers or in a mixture of the two catalysts in a single washcoat layer.
  • the lean NO ⁇ catalyst employed in the hybrid catalyst invention preferably is a transition metal-exchanged zeolite, desirably a high silica zeolite having a Si0 2 /Al 2 0 3 molar ratio which preferably exceeds about 10, and is more preferably up to about 60 (see U.S. Patent 4,297,328, which is expressly incorporated herein by reference for teaching of other zeolites or class or zeolites that may be used herein) .
  • transition metal used to exchange the preferred zeolite herein is limited to the group of copper, cobalt, nickel, chromium, iron, manganese, silver, zinc, calcium, and compatible mixtures thereof; transition metal as used herein includes the elemental metal itself as well as the metal oxide thereof.
  • the preferred transition metal is copper, and the preferred zeolite is a copper exchanged ZSM5 zeolite. The transition metal is provided into the zeolite by ion exchange.
  • a sodium, hydrogen, or ammonium zeolite is contacted by an aqueous solution of another cation, in this case an aqueous solution of a soluble transition metal compound, such as copper acetate, wherein replacement of the sodium, hydrogen or ammonium ion by copper ion takes place.
  • a soluble transition metal compound such as copper acetate
  • the zeolite is generally washed to remove excess surface transition metal compound. It is not necessary to do so, however.
  • the lean NO ⁇ catalyst used in the invention hybrid catalyst need not, however, necessarily be an ion-exchanged zeolite material.
  • suitable materials for the LNC portion of the hybrid catalyst could consist of a transition metal such as copper, cobalt, nickel, chromium, iron, manganese, silver, zinc, or precious metal such as platinum, palladium, rhodium, rhenium, osmium, iridium and compatible mixtures thereof dispersed within the pores of a support material such as alumina, silica, titania, zirconia.
  • the first catalyst is capable of selectively reducing nitrogen oxides with hydrocarbons in the presence of oxygen so that at least about 30% of the nitrogen oxides are converted, more preferably this amount is at least about 50%, under the operating temperatures of lean-burn engines.
  • the second catalyst of the hybrid catalyst of this invention is a three-way catalyst (TWC) which is suitable to simultaneously convert the components of exhaust gases, such as those from an internal combustion engine like hydrocarbons, carbon monoxide, and nitrogen oxides into more desirable species like carbon dioxide, water, and nitrogen under near stoichiometric engine conditions.
  • TWC three-way catalyst
  • Such catalysts are well known to those skilled in the art.
  • Exemplary of suitable three-way catalysts include conventional three-way catalysts containing either platinum and rhodium, palladium and rhodium, or palladium in combination with various promoters and stabilisers such as ceria, barium oxide, lanthanum oxide, or strontium supported on an high surface area carrier such as alumina. Still other TWCs which may be employed in this invention will be apparent to those skilled in the art in view of the present disclosure.
  • the first catalyst and the second catalyst are preferably employed in this invention as disclosed above as washcoat materials which are deposited directly onto a substrate.
  • the substrate is generally made of an electrically insulating material suitable for high temperature environments including, but not limited to, materials such as cordierite, mullite, etc.
  • the substrate may be in any suitable configuration, often being employed as a monolithic honeycomb structure, spun fibres, corrugated foils or layered materials. Still other materials and configurations useful in this invention and suitable in an exhaust gas system will be apparent to those skilled in the art in view of this disclosure.
  • the three-way catalyst and lean NO ⁇ catalyst materials can be applied to the substrate as a mixture or in two sequential but separate steps in a manner which would be readily apparent to those skilled in the art of catalyst manufacture.
  • the three-way catalyst material would be applied to the substrate first followed by a drying and calcination step then the lean NO ⁇ catalyst material would be applied directly on top of the previously deposited three-way catalyst material followed by a second drying and calcination.
  • the preferred outcome of the preparation procedure is a catalyst with an inner layer of three-way catalyst material and an outer most layer of lean NO ⁇ catalyst material.
  • a high silica zeolite ion-exchanged with copper was obtained from a commercial source as Cu-ZSM5.
  • the material contained 3% by weight and was in a powder form which was suitable for direct use.
  • the above material was ball milled then mixed with distilled water to produce a slurry.
  • the resulting slurry was applied as an outer layer to a 92in cordierite monolith which carried a palladium based three- way catalyst washcoat to obtain a 15 wt% loading of the copper zeolite.
  • the above three-way catalyst contained 110gm/ft 3 of palladium on alumina as a carrier and was obtained from a commercial source.
  • Fig. 1 shows a graph of NO ⁇ conversion efficiency as a function of A/F ratio for the hybrid LNC/TWC of this example compared to the TWC alone.
  • the data was obtained by using a simulated automobile exhaust gas produced by the combustion of isooctaine fuel in a laboratory pulse flame combustor.
  • the catalysts were tested at a space velocity of 20,000hr -1 and at a gas temperature of 500°C.
  • the invention hybrid LNC/TWC provides for significantly improved NO ⁇ conversion efficiency on the lean side of stoichiometry compared to the TWC alone.
  • Fig. 2 compares the cold start hydrocarbon conversions for the hybrid LNC/TWC " and the LNC+TWC in series (described in this example) during the first 120 seconds of the FTP test.
  • hydrocarbon conversion efficiency during cold starting of the engine is significantly better with the hybrid LNC/TWC.
  • the LNC+TWC in series With the LNC+TWC in series, light- off of the TWC is greatly delayed because the LNC acts as a heat sink which slows down the warming of the TWC to its necessary activation temperature.
  • cold start hydrocarbon conversion efficiency is less than desirable to attempt to meet projected government hydrocarbon emission standards.
  • This same effect is further reflected in the hydrocarbon tailpipe emissions for Bag One of the FTP test as shown in Table 1. Bag One tailpipe HC emissions are more than 50% higher with the LNC+TWC in series compared the hybrid LNC/TWC.
  • Table 1 also compares NO tailpipe emissions and NO ⁇ conversion efficiency for the hybrid LNC/TWC to the LNC+TWC in series.
  • NO ⁇ tailpipe emissions with the LNC+TWC in series are slightly lower. However, this difference is not deemed to be significant.
  • the availability of hydrocarbons for lean N0 ⁇ catalysis was maximised, thereby providing for nearly equivalent lean NO ⁇ conversion efficiencies compared to the LNC+TWC in series.
  • Feedgas 2.97 g/ml 2.75 g/ml 1.12 g/ml 1.07 g/ml

Landscapes

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

Abstract

Catalyseur hybride destiné à la purification de gaz d'échappement produits par un moteur fonctionnant à des taux de combustion air/carburant tant stoechiométriques qu'à mélange pauvre (riche en oxygène). Ledit catalyseur hybride comprend un premier catalyseur composé d'un matériau catalytique capable de réduire les oxydes d'azote dans des conditions de fonctionnement à mélange pauvre du moteur et un second catalyseur composé d'un catalyseur à trois voies. De préférence, ledit catalyseur hybride est une combinaison de catalyseurs en couches, la couche de premier catalyseur étant placée sur la couche de second catalyseur, elle-même portée par un substrat tel que de la cordiérite.
PCT/GB1995/001499 1994-07-05 1995-06-26 Catalyseur hybride de gaz d'echappement WO1996001142A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU27491/95A AU2749195A (en) 1994-07-05 1995-06-26 Hybrid exhaust gas catalyst

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US27029594A 1994-07-05 1994-07-05
US270,295 1994-07-05

Publications (1)

Publication Number Publication Date
WO1996001142A1 true WO1996001142A1 (fr) 1996-01-18

Family

ID=23030733

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1995/001499 WO1996001142A1 (fr) 1994-07-05 1995-06-26 Catalyseur hybride de gaz d'echappement

Country Status (2)

Country Link
AU (1) AU2749195A (fr)
WO (1) WO1996001142A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL1003778C2 (nl) * 1996-08-09 1998-02-12 Univ Delft Tech Werkwijze ter vervaardiging van een composiet-katalysator.
EP0868940A1 (fr) * 1997-03-31 1998-10-07 Mazda Motor Corporation Catalyseur pour la purification de gaz d'échappement, procédé pour la fabrication et pour l'usage du catalyseur
US10746752B2 (en) 2009-11-13 2020-08-18 Ventana Medical Systems, Inc. Opposables and automated specimen processing systems with opposables

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01139145A (ja) * 1987-11-25 1989-05-31 Toyota Motor Corp 排気浄化用触媒
EP0369576A1 (fr) * 1988-11-18 1990-05-23 Corning Incorporated Catalyseur tamis moléculaire-palladium-platine sur un substrat
EP0464709A1 (fr) * 1990-07-02 1992-01-08 Mitsubishi Jukogyo Kabushiki Kaisha Procédé pour nettoyer les gaz d'échappement des moteurs à combustion interne
EP0485180A1 (fr) * 1990-11-09 1992-05-13 Ngk Insulators, Ltd. Composition pour catalyseur et catalyseur pour la purification des effluents gazeux et procédé pour sa préparation
US5179053A (en) * 1991-11-08 1993-01-12 Ford Motor Company Treating exchaust from a compressed natural gas-fueled engine

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01139145A (ja) * 1987-11-25 1989-05-31 Toyota Motor Corp 排気浄化用触媒
EP0369576A1 (fr) * 1988-11-18 1990-05-23 Corning Incorporated Catalyseur tamis moléculaire-palladium-platine sur un substrat
EP0464709A1 (fr) * 1990-07-02 1992-01-08 Mitsubishi Jukogyo Kabushiki Kaisha Procédé pour nettoyer les gaz d'échappement des moteurs à combustion interne
EP0485180A1 (fr) * 1990-11-09 1992-05-13 Ngk Insulators, Ltd. Composition pour catalyseur et catalyseur pour la purification des effluents gazeux et procédé pour sa préparation
US5179053A (en) * 1991-11-08 1993-01-12 Ford Motor Company Treating exchaust from a compressed natural gas-fueled engine

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
DATABASE WPI Section Ch Week 8928, Derwent World Patents Index; Class H06, AN 89-201844 *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL1003778C2 (nl) * 1996-08-09 1998-02-12 Univ Delft Tech Werkwijze ter vervaardiging van een composiet-katalysator.
WO1998006495A1 (fr) * 1996-08-09 1998-02-19 Technische Universiteit Delft Procede de preparation d'un catalyseur composite
EP0868940A1 (fr) * 1997-03-31 1998-10-07 Mazda Motor Corporation Catalyseur pour la purification de gaz d'échappement, procédé pour la fabrication et pour l'usage du catalyseur
US10746752B2 (en) 2009-11-13 2020-08-18 Ventana Medical Systems, Inc. Opposables and automated specimen processing systems with opposables

Also Published As

Publication number Publication date
AU2749195A (en) 1996-01-25

Similar Documents

Publication Publication Date Title
US5727385A (en) Lean-burn nox catalyst/nox trap system
US6497851B1 (en) Engine exhaust treatment apparatus and method of use
US5750082A (en) Nox trap with improved performance
EP1252925B1 (fr) Catalyseur et méthode de purification des gaz d'échapement
EP1048341B1 (fr) Catalyseur comprenant un mélange de particules de platinum sur alumina et d'oxyde mixte de manganèse et de zirconium
CA2224958C (fr) Catalyseur pour la purification des gaz d'echappement et systeme de purification de ces gaz
EP0562516B1 (fr) Méthode pour la purification de gaz d'échappement
US5837212A (en) Potassium/manganese nitrogen oxide traps for lean-burn engine operation
EP2922629A1 (fr) Catalyseur zoné sur un substrat monolithique
GB2492175A (en) Catalysed substrate and exhaust system for internal combustion engine
CA2534806A1 (fr) Ensemble catalyseur et procede de purification des gaz d'echappement de moteurs a combustion interne actionnes dans des conditions pauvres
US6191061B1 (en) Method of purifying exhaust gas and catalyst for purifying exhaust gas
US6489259B2 (en) Mixed zeolite NOx catalyst
US5939037A (en) Sulfur tolerant NOx traps highly loaded with sodium or potassium
US20020076373A1 (en) Use of lithium in NOx adsorbers for improved low temperature performance
JPH11221466A (ja) 排気ガス浄化用触媒及び排気ガス浄化方法
WO1996001142A1 (fr) Catalyseur hybride de gaz d'echappement
US5876680A (en) Bimetallic tungsten/platinum catalysts for lean-burn emissions
JP4290391B2 (ja) 窒素酸化物を接触的に除去するための方法とそのための装置
JP3732124B2 (ja) 窒素酸化物を接触還元する方法とそのための触媒
EP0868940A1 (fr) Catalyseur pour la purification de gaz d'échappement, procédé pour la fabrication et pour l'usage du catalyseur
JPH11138005A (ja) 排ガス浄化用触媒及びその製造方法
JPH0824655A (ja) 排気ガス浄化用触媒
JPH11138006A (ja) 排気ガス浄化用触媒及び浄化方法
JPH10235199A (ja) 排気ガス浄化用触媒

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AU CA JP KR

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): AT BE CH DE DK ES FR GB GR IE IT LU MC NL PT SE

DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
121 Ep: the epo has been informed by wipo that ep was designated in this application
122 Ep: pct application non-entry in european phase
NENP Non-entry into the national phase

Ref country code: CA