EP2496801A1 - Device for treating exhaust gases from a vehicle comprising a heat engine - Google Patents

Device for treating exhaust gases from a vehicle comprising a heat engine

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Publication number
EP2496801A1
EP2496801A1 EP10785156A EP10785156A EP2496801A1 EP 2496801 A1 EP2496801 A1 EP 2496801A1 EP 10785156 A EP10785156 A EP 10785156A EP 10785156 A EP10785156 A EP 10785156A EP 2496801 A1 EP2496801 A1 EP 2496801A1
Authority
EP
European Patent Office
Prior art keywords
treatment device
catalyst
soot
selective reduction
aging
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Withdrawn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
EP10785156A
Other languages
German (de)
French (fr)
Inventor
Gilbert Blanchard
Alain Sassi
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.)
PSA Automobiles SA
Original Assignee
Peugeot Citroen Automobiles SA
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 Peugeot Citroen Automobiles SA filed Critical Peugeot Citroen Automobiles SA
Publication of EP2496801A1 publication Critical patent/EP2496801A1/en
Withdrawn legal-status Critical Current

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Classifications

    • 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
    • F01N3/206—Adding periodically or continuously substances to exhaust gases for promoting purification, e.g. catalytic material in liquid form, NOx reducing agents
    • 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
    • B01D53/9472—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 zones
    • 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
    • B01D53/9477—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 separate bricks, e.g. exhaust systems
    • B01J35/613—
    • 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
    • F01N13/00—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00
    • F01N13/009—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having two or more separate purifying devices arranged in series
    • F01N13/0097—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having two or more separate purifying devices arranged in series the purifying devices are arranged in a single housing
    • 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
    • F01N3/02—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
    • F01N3/021—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters
    • F01N3/023—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters using means for regenerating the filters, e.g. by burning trapped particles
    • F01N3/0231—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters using means for regenerating the filters, e.g. by burning trapped particles using special exhaust apparatus upstream of the filter for producing nitrogen dioxide, e.g. for continuous filter regeneration systems [CRT]
    • 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
    • F01N3/0807—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents
    • F01N3/0821—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents combined with particulate filters
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2251/00—Reactants
    • B01D2251/20—Reductants
    • B01D2251/206—Ammonium compounds
    • B01D2251/2067—Urea
    • 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
    • B01D2255/2065—Cerium
    • 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
    • B01D2255/20707—Titanium
    • 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
    • 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
    • B01D2255/20738—Iron
    • 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
    • B01D2255/20776—Tungsten
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/30—Silica
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/50—Zeolites
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/90—Physical characteristics of catalysts
    • B01D2255/903—Multi-zoned catalysts
    • B01D2255/9032—Two zones
    • 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
    • B01D2255/9207—Specific surface
    • 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
    • B01J21/00—Catalysts comprising the elements, oxides, or hydroxides of magnesium, boron, aluminium, carbon, silicon, titanium, zirconium, or hafnium
    • B01J21/06—Silicon, titanium, zirconium or hafnium; Oxides or hydroxides thereof
    • B01J21/063—Titanium; Oxides or hydroxides thereof
    • 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
    • B01J23/16—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
    • B01J23/24—Chromium, molybdenum or tungsten
    • B01J23/30—Tungsten
    • 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
    • B01J29/00—Catalysts comprising molecular sieves
    • B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
    • B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
    • B01J29/65—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the ferrierite type, e.g. types ZSM-21, ZSM-35 or ZSM-38, as exemplified by patent documents US4046859, US4016245 and US4046859, respectively
    • B01J29/66—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the ferrierite type, e.g. types ZSM-21, ZSM-35 or ZSM-38, as exemplified by patent documents US4046859, US4016245 and US4046859, respectively containing iron group metals, noble metals or copper
    • B01J29/68—Iron group metals or copper
    • 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
    • F01N2250/00—Combinations of different methods of purification
    • F01N2250/02—Combinations of different methods of purification filtering and catalytic conversion
    • 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
    • F01N3/02—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
    • F01N3/021—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters
    • F01N3/033—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters in combination with other devices
    • F01N3/035—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters in combination with other devices with catalytic reactors, e.g. catalysed diesel particulate filters
    • 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

  • Device for treating the exhaust gases of a vehicle comprising a heat engine.
  • the present invention relates to a device for treating the exhaust gas of a vehicle comprising a heat engine, equipped with an exhaust gas depollution device for treating unburned hydrocarbons, carbon monoxide to the of a treatment system by catalytic selective reduction of nitrogen oxides emitted by the engine and a fuel additive system used by the engine.
  • Thermal engines such as those used by private vehicles or heavy vehicles, emit a number of emissions that should be limited to minimize the dissipation of pollutants such as nitrogen oxides, carbon monoxide or particles consisting for example of unburned hydrocarbons.
  • the selective reduction of nitrogen oxides is commonly practiced for the purification of stationary plant fumes, using as a selective agent ammonia stored in a suitable tank.
  • an ammonia precursor is used, such as pure urea or in solution. aqueous. Urea or urea solution is injected into the exhaust line; the water contained in the solution is vaporized and then the urea (NH 2 ) 2CO is decomposed into ammonia and isocyanic acid, said acid being itself hydrolysed by thermolysis.
  • urea into the exhaust line must be carried out either continuously or pulsed and precisely dosed, in order to to treat all the nitrogen oxides present and secondly, to avoid untimely emission of ammonia.
  • the continuous selective reduction by ammonia on catalysts based on zeolites exchanged with either iron or copper is one of the technologies well known to those skilled in the art and it is well suited for applications on DIESEL vehicles, but has a low temperature limitation, typically this process is not implemented when the catalyst inlet temperature is below about 170 ° C.
  • NOx trap Another nitrogen oxides reduction device known under the name NOx trap consists of trapping the nitrogen oxides in the form of nitrates at low temperature and then reducing these nitrates to nitrogen by passages in a rich medium, it is possible to ie when the exhaust gases are reducing.
  • This device is very intrusive at engine settings and is not very efficient at high temperatures because the storage capacity of NOx on the NOx trap phases drops sharply from 350 ° C.
  • the exhaust lines are also equipped with filters, known as particle filters, which trap in particular the unburnt particles due to a temperature of the exhaust gas substantially too low.
  • particle filters filters, known as particle filters, which trap in particular the unburnt particles due to a temperature of the exhaust gas substantially too low.
  • the filter is filter wall type, ceramic, for example cordierite, or silicon carbide, or aluminum titanium, through which the exhaust gas flow. It may also be sieves made of wire cloth, ceramic foam or fibrous material.
  • This filter is capable of stopping a high proportion of soot generated by the combustion of the fuel in the engine. However, it becomes less and less effective as the soot accumulates because it closes progressively the filter, which leads to a pressure drop that increases in the filter, and ultimately reduces the performance of the engine. It is therefore necessary to regularly burn the soot collected by the filters, by an operation called "regeneration of the filter". Also, periodically, these filters must be regenerated by temporarily increasing the temperature of the exhaust gas to burn the filtered particles.
  • a regeneration technique uses a so-called catalyzed filter particle filter, which is composed of a filter and a catalytic phase deposited in the porosity of the filter walls of the filter.
  • These catalytic phases may be based on noble metals such as platinum deposited on supports such as alumina or cerium-zirconium oxides, or based on mixed oxides such as cerium-zirconium-praseodymium ternary oxides.
  • This technique also has drawbacks: noble metals are complex to form on supports, and are an expensive raw material. And the ternary oxides have a modest efficiency at low temperature, which imposes relatively long filter regeneration times, so overconsumption fuel.
  • an exhaust gas treatment device consisting of a particulate filter disposed in the exhaust line, retaining the soot and particles and loaded on its outer face with a SCR catalytic material for reducing NOx, means being provided to bring ammonia into the exhaust line upstream of the particulate filter.
  • a SCR catalytic material for reducing NOx means being provided to bring ammonia into the exhaust line upstream of the particulate filter.
  • Regeneration can also be cyclically in a known manner by increasing the hydrocarbon content in the exhaust gas.
  • the reaction that follows is highly exothermic and may damage the SCR catalyst material.
  • the SCR catalysts proposed in US 2008/0041040 are not sufficiently resistant to thermal stresses and therefore lose their effectiveness over time and their use.
  • the present invention aims to propose a device for treating exhaust gases from an engine.
  • thermal device comprising a particulate filter consisting of a porous material for trapping and oxidizing soot and a selective reduction catalyst of the nitrogen oxides deposited on the outlet faces of the walls of the particulate filter, characterized in that said catalyst selective reduction is chosen from those of the type having a specific surface area of at least 65M 2 / g after aging at 800 ° C.
  • the catalyst material SCR is chosen to advantageously withstand the thermal stresses encountered during the regeneration of the particulate filter and be thermally stable so that the treatment device according to the invention has all the qualities required to meet the requirements of the invention. standards increasingly severe.
  • the specific surface of the catalyst remains high even after aging, that is to say after having been subjected to hydrothermal stresses at 800 ° C.
  • said selective reduction catalyst is chosen from those of the type having a specific surface area of at least 65M 2 / g after aging at 850 ° C. Even more preferably, the selective reduction catalyst is selected from those of the type having a surface area of at least 65M 2 / g after aging at 900 ° C.
  • specific surface is meant the specific surface B.E.T. determined by nitrogen adsorption according to ASTM D 3663-78 established from the BRUNAUER-EMMETT-TELLER method described in the periodical "The Journal of the American Chemical Society, 60,309 (1938).
  • an SCR catalyst material for a device according to the invention may be chosen from acidic oxides such as those described by the company Rhodia, the commercial SCR catalytic phase based on Zr-Ti-Si-W-Ce and any other catalyst material having a surface area of at least 65 M 2 / g after aging at 800 ° C.
  • the oxidation of soot in the treatment device is promoted by the use of an additive Ce or Ce-Fe or Fe introduced into the fuel that lowers the soot combustion temperature.
  • an exhaust gas treatment device in the inlet channels from which the particles are retained and are the soot is then oxidized during regeneration, the soot being oxidized to CO 2 and H 2 O, at a temperature lowered by means of the additive from the fuel and deposited on the soot while on the wall of the outlet the reduction of NOx by ammonia on the SCR catalyst deposited on these filtering walls.
  • urea or ammonia may be introduced upstream of the treatment device according to the invention.
  • urea is introduced into the exhaust line downstream of the oxidation catalyst of CO and hydrocarbons and upstream of the treatment device according to the invention.
  • a catalyst for decomposing urea ammonia deposited on the inlet channels of the particle filter of the treatment device according to the invention is preferably provided. The urea is thus decomposed in the wall of the particle filter, which makes it possible to avoid using a mixer upstream of the Filter / SCR device.
  • the invention also relates to a motor vehicle comprising such a treatment device.
  • Example 1 Device according to the state of the art
  • Example 1 a processing device is produced according to the prior state described in US 2008/004140, an SCR catalyst according to this document being deposited on the outlet face of a particulate filter (FAP).
  • FAP particulate filter
  • composition of the SCR catalyst in the SiC particle filter of 400 cpsi is as follows:
  • FAP deposition of anatase titanium oxide, on the exit channels of the FAP deposition of 101 grs / l of FAP of a commercial SCR catalyst based on 2% by weight of iron deposited on a zeolite ferrierite.
  • Example 2 is carried out a device according to the invention by deposition of a commercial SCR catalytic phase based on Zr-Ti-Si-W-Ce on a 400cpsi SiC particle filter.
  • This active phase is deposited on the outlet wall of the particle filter channels by conventional dipping, blowing, drying and calcining at 500 ° C.
  • composition of the catalyst according to the invention is as follows:
  • Example 3 Aging Devices of Examples 1 and 2
  • This hydrothermal treatment is applied to represent the hydrothermal aging that the FAP-catalyst devices undergo during regeneration of particulate filters under real conditions on the vehicle.
  • Catalyst A for the catalyst of Example 1 aged at 850 ° C.
  • Catalyst B for the catalyst of the invention described in Example 2 aged at 850 ° C.
  • the catalysts A and B are evaluated on a synthetic gas bench under the following conditions:
  • NO x 400 ppm (50% N0 + 50% NO2)
  • VVH Hourly Volumetric Velocity
  • Temperature programming from 180 to 500 ° C with a temperature rise rate of 5 ° C per minute.
  • composition of the gases leaving the catalytic reactor is measured by -
  • Table 1 NOx Conversion as a Function of Temperature for Catalysts A and B The results reported in Table 1 show that the catalyst B according to the invention is more efficient in reducing NOx than the catalyst A according to the prior art.

Abstract

The invention relates to a device for treating the exhaust gases from a heat engine, said device comprising a particle filter that is formed of a porous material for trapping and oxidizing the soot and a catalyst for selectively reducing the nitrogen oxides deposited on the outlet surfaces of the walls of the particle filter. The invention involves selecting said selective reduction catalyst from among those having a specific surface area of at least 65 m2/g after ageing to 800° C.

Description

Dispositif de traitement des gaz d'échappement d'un véhicule comportant un moteur thermique.  Device for treating the exhaust gases of a vehicle comprising a heat engine.
[0001 ] La présente invention revendique la priorité de la demande française 0957784 déposée le 04 Novembre 2009 dont le contenu (texte et revendications) est ici incorporé par référence.  The present invention claims the priority of the French application 0957784 filed on November 04, 2009 whose content (text and claims) is here incorporated by reference.
[0002] La présente invention concerne un dispositif de traitement des gaz d'échappement d'un véhicule comportant un moteur thermique, équipé d'un dispositif de dépollution des gaz d'échappement permettant de traiter les hydrocarbures imbrûlés, le monoxyde de carbone à la fois d'un système de traitement par réduction catalytique sélective des oxydes d'azote émis par le moteur et d'un système d'additivation du carburant utilisé par le moteur thermique.  The present invention relates to a device for treating the exhaust gas of a vehicle comprising a heat engine, equipped with an exhaust gas depollution device for treating unburned hydrocarbons, carbon monoxide to the of a treatment system by catalytic selective reduction of nitrogen oxides emitted by the engine and a fuel additive system used by the engine.
[0003] Les moteurs thermiques tels que ceux utilisés par les véhicules particuliers ou les véhicules de type poids lourd, émettent un certain nombre d'émissions qu'il convient de limiter pour minimiser la dissipation de polluants comme par exemple des oxydes d'azote, du monoxyde de carbone ou des particules constituées par exemple par des hydrocarbures imbrûlés.  Thermal engines such as those used by private vehicles or heavy vehicles, emit a number of emissions that should be limited to minimize the dissipation of pollutants such as nitrogen oxides, carbon monoxide or particles consisting for example of unburned hydrocarbons.
[0004] C'est pourquoi ces dernières années ont vu se multiplier les équipements de traitement des gaz d'échappement du moteur. Nombre de ces traitements supposent le recours à des additifs stockés dans des réservoirs spécifiques pour aider d'une part à la réduction de certains composés comme l'oxyde d'azote et d'autre part à l'oxydation d'autres composés comme des hydrocarbures imbrûlés ou des suies.  This is why in recent years have seen the multiplication of engine exhaust gas treatment equipment. Many of these treatments involve the use of additives stored in specific tanks to help on the one hand to reduce certain compounds such as nitrous oxide and on the other hand to the oxidation of other compounds such as hydrocarbons unburned or sooty.
[0005] La réduction sélective des oxydes d'azote est pratiquée couramment pour l'épuration des fumées d'usines stationnaires, en utilisant à titre d'agent sélectif de l'ammoniac stocké dans un réservoir approprié. Compte tenu du caractère toxique de l'ammoniac et du risque de fuite inhérent à l'industrie automobile, notamment en cas d'accident, pour les véhicules on utilise plutôt un précurseur d'ammoniac, tel que de l'urée pure ou en solution aqueuse. L'urée ou la solution d'urée est injectée dans la ligne d'échappement ; l'eau contenue dans la solution se vaporise puis l'urée (NH2)2C0 est décomposée en ammoniac et en acide isocyanique, ledit acide étant lui- même hydrolysé par thermolyse. L'injection d'urée dans la ligne d'échappement doit être effectuée de manière soit continue soit puisée et précisément dosée, afin d'une part de traiter l'ensemble des oxydes d'azote présents et d'autre part, d'éviter émission intempestive d'ammoniac. Parmi les dispositifs de réduction des oxydes d'azote, la réduction sélective en continu par l'ammoniac sur des catalyseurs à base de zéolithes échangées par soit du fer soit du cuivre est une des technologies bien connue de l'homme de l'art et elle est bien adaptée pour des applications sur véhicules DIESEL, mais présente une limitation à basse température, typiquement ce procédé n'est pas mis en œuvre lorsque la température entrée catalyseur est inférieure à environ 170°C. The selective reduction of nitrogen oxides is commonly practiced for the purification of stationary plant fumes, using as a selective agent ammonia stored in a suitable tank. Given the toxic nature of ammonia and the risk of leakage inherent in the automobile industry, particularly in the event of an accident, for vehicles an ammonia precursor is used, such as pure urea or in solution. aqueous. Urea or urea solution is injected into the exhaust line; the water contained in the solution is vaporized and then the urea (NH 2 ) 2CO is decomposed into ammonia and isocyanic acid, said acid being itself hydrolysed by thermolysis. The injection of urea into the exhaust line must be carried out either continuously or pulsed and precisely dosed, in order to to treat all the nitrogen oxides present and secondly, to avoid untimely emission of ammonia. Among the devices for reducing nitrogen oxides, the continuous selective reduction by ammonia on catalysts based on zeolites exchanged with either iron or copper is one of the technologies well known to those skilled in the art and it is well suited for applications on DIESEL vehicles, but has a low temperature limitation, typically this process is not implemented when the catalyst inlet temperature is below about 170 ° C.
[0006] Un autre dispositif de réduction des oxydes d'azote connu sous la dénomination NOx trap consiste à piéger les oxydes d'azote sous forme de nitrates à basse température puis à réduire ces nitrates en azote par des passages en milieu riche, c'est à dire lorsque les gaz d'échappement sont réducteurs. Ce dispositif est très intrusif au niveau des réglages moteur et il est peu efficace à haute température car la capacité de stockage des NOx sur les phases NOx trap baisse fortement à partir de 350 °C.  Another nitrogen oxides reduction device known under the name NOx trap consists of trapping the nitrogen oxides in the form of nitrates at low temperature and then reducing these nitrates to nitrogen by passages in a rich medium, it is possible to ie when the exhaust gases are reducing. This device is very intrusive at engine settings and is not very efficient at high temperatures because the storage capacity of NOx on the NOx trap phases drops sharply from 350 ° C.
[0007] Par ailleurs, pour limiter les émissions de particules, en particulier avec des moteurs utilisant un carburant de type diesel, les lignes d'échappement sont également équipées de filtres, dits filtres à particules, qui piègent notamment les particules imbrûlées du fait d'une température des gaz d'échappement essentiellement trop faible. On sait effectivement que la combustion du gazole dans les moteurs de type diesel (ou les moteurs fonctionnant en mélange pauvre) tend à former des produits carbonés sous forme de particules, ces particules carbonées étant usuellement désignées sous le terme de « suies ». On cherche donc à diminuer au maximum l'émission de ces suies, ces suies étant susceptibles de soulever des problèmes de santé et des problèmes environnementaux.  Furthermore, to limit particulate emissions, particularly with engines using a diesel-type fuel, the exhaust lines are also equipped with filters, known as particle filters, which trap in particular the unburnt particles due to a temperature of the exhaust gas substantially too low. It is well known that the combustion of diesel in diesel engines (or lean-burn engines) tends to form carbonaceous products in the form of particles, these carbonaceous particles being usually referred to as "soot". So we try to minimize the emission of soot, soot is likely to raise health problems and environmental problems.
[0008] Typiquement, le filtre est de type à parois filtrantes, en céramique, par exemple en cordiérite, ou en carbure de silicium, ou en titane d'aluminium, à travers lequel circulent les gaz d'échappement. Il peut aussi s'agir de tamis en toile métallique, en mousse céramique ou en matériau fibreux.  Typically, the filter is filter wall type, ceramic, for example cordierite, or silicon carbide, or aluminum titanium, through which the exhaust gas flow. It may also be sieves made of wire cloth, ceramic foam or fibrous material.
[0009] Ce filtre est capable d'arrêter une forte proportion des suies engendrées par la combustion des combustibles dans le moteur. Il devient cependant de moins en moins efficace au fur et à mesure que les suies s'y accumulent, car elles obturent progressivement le filtre, ce qui conduit à une perte de charge qui augmente dans le filtre, et ce qui finit par diminuer la performance du moteur. Il est donc nécessaire de brûler régulièrement les suies collectées par les filtres, par une opération appelée « régénération du filtre ». Aussi, périodiquement, ces filtres doivent être régénérés en augmentant temporairement la température des gaz d'échappement pour brûler les particules filtrées. This filter is capable of stopping a high proportion of soot generated by the combustion of the fuel in the engine. However, it becomes less and less effective as the soot accumulates because it closes progressively the filter, which leads to a pressure drop that increases in the filter, and ultimately reduces the performance of the engine. It is therefore necessary to regularly burn the soot collected by the filters, by an operation called "regeneration of the filter". Also, periodically, these filters must be regenerated by temporarily increasing the temperature of the exhaust gas to burn the filtered particles.
[0010] Selon une technique de régénération, on a recours à un filtre à particules dit filtre catalysé, qui est composé d'un filtre et d'une phase catalytique déposée dans la porosité des parois filtrantes du filtre. Ces phases catalytiques peuvent être à base de métaux nobles comme le platine déposé sur des supports comme de l'alumine ou des oxydes de cérium-zirconium, ou à base d'oxydes mixtes comme des oxydes ternaire cérium-zirconium-praséodyme. Cette technique présente également des inconvénients: les métaux nobles sont complexes à mettre en forme sur des supports, et sont une matière première coûteuse. Et les oxydes ternaires présentent une efficacité modeste à basse température, ce qui impose des temps de régénération du filtre relativement longs, donc une surconsommation en carburant.  According to a regeneration technique, it uses a so-called catalyzed filter particle filter, which is composed of a filter and a catalytic phase deposited in the porosity of the filter walls of the filter. These catalytic phases may be based on noble metals such as platinum deposited on supports such as alumina or cerium-zirconium oxides, or based on mixed oxides such as cerium-zirconium-praseodymium ternary oxides. This technique also has drawbacks: noble metals are complex to form on supports, and are an expensive raw material. And the ternary oxides have a modest efficiency at low temperature, which imposes relatively long filter regeneration times, so overconsumption fuel.
[001 1 ] Par ailleurs, dans le cadre de la protection de l'environnement, les législations soit Américaine Tier2 Bin 5 soit Européenne Euro 5 puis EURO 6 sont de plus en plus sévères sur les rejets de polluants de tous les moteurs et plus particulièrement sur les émissions d'oxydes d'azote.  [001 1] Moreover, in the context of environmental protection, the laws are American Tier2 Bin 5 or European Euro 5 then EURO 6 are increasingly severe on pollutant releases of all engines and more particularly on emissions of nitrogen oxides.
[0012] La mise en place des nouvelles normes prévues à des échéances aussi proches que 2014 pour EURO 6, va imposer aux constructeurs automobiles d'équiper les véhicules DIESEL ou Essence Lean-burn de dispositifs de réduction des oxydes d'azote.  The implementation of the new standards planned for maturities as close as 2014 for EURO 6, will require automakers to equip vehicles DIESEL or Lean-burn gasoline devices for reducing nitrogen oxides.
[0013] Il est donc souhaitable de pouvoir équiper un véhicule à la fois d'un système très performant pour la réduction des oxydes d'azote et d'un système très performant pour éliminer les particules, en combinant dans une ligne d'échappement des moyens de type SCR et des moyens de type filtre à particules éventuellement associés à des moyens pour enrichir le carburant en additifs. It is therefore desirable to be able to equip a vehicle at a time with a very efficient system for the reduction of nitrogen oxides and a very efficient system for removing particles, by combining in an exhaust line of SCR type means and particulate filter type means optionally associated with means for enriching the fuel with additives.
[0014] Il est donc ainsi connu de proposer des dispositifs de dépollution comportant à la fois un filtre à particules et un système SCR dans la ligne d'échappement d'un véhicule. Cependant, se pose alors un problème d'encombrement lié aux deux systèmes positionnés le long de la ligne d'échappement. It is thus well known to provide pollution control devices comprising both a particulate filter and an SCR system in the exhaust line of a vehicle. However, there then arises a congestion problem related to the two systems positioned along the exhaust line.
[0015] On a alors proposé de déposer des phases actives de type SCR dans la porosité d'un filtre à particule de manière à obtenir un dispositif de dépollution plus compact.  It was then proposed to deposit active phases of the SCR type in the porosity of a particle filter so as to obtain a more compact pollution control device.
[0016] Ainsi, dans US 2008/0041040 est proposé un dispositif de traitement des gaz d'échappement constitué d'un filtre à particules disposé dans la ligne d'échappement, retenant les suies et particules et chargé sur sa face extérieure d'un matériau de catalyse SCR pour réduire les NOx, des moyens étant prévus pour amener de l'ammoniaque dans la ligne d'échappement en amont du filtre à particules. De manière à provoquer une oxydation des suies à l'entrée du FAP, on peut positionner en amont dudit dispositif, un convertisseur catalytique à oxydation permettant de convertir une partie des NOx contenus dans les gaz d'échappement en dioxyde d'azote (NO2). En conséquence, une oxydation continue des particules de carbone accumulées sur le FAP peut alors être effectuée ce qui permet de régénérer ce FAP à une température plus basse que celle utilisée par une régénération par mélange riche ou par addition d'hydrocarbures dans les gaz d'échappement.  Thus, in US 2008/0041040 is proposed an exhaust gas treatment device consisting of a particulate filter disposed in the exhaust line, retaining the soot and particles and loaded on its outer face with a SCR catalytic material for reducing NOx, means being provided to bring ammonia into the exhaust line upstream of the particulate filter. In order to cause soot oxidation at the inlet of the FAP, it is possible to position upstream of said device an oxidation catalytic converter making it possible to convert part of the NOx contained in the exhaust gases to nitrogen dioxide (NO2). . Consequently, a continuous oxidation of the carbon particles accumulated on the FAP can then be carried out, which makes it possible to regenerate this FAP at a lower temperature than that used by a regeneration by rich mixture or by the addition of hydrocarbons in the gases of exhaust.
[0017] Bien qu'un tel dispositif de dépollution présente un encombrement plus limité que ceux prévoyant un FAP et un dispositif SCR séparés dans la ligne d'échappement, la présence du convertisseur catalytique à oxydation contenant du platine permettant d'oxyder le NO en NO2 présente également des inconvénients: les métaux nobles sont complexes à mettre en forme sur des supports, et sont une matière première coûteuse qui augmente le coût d'un tel système.  Although such a pollution control device has a more limited footprint than those providing a separate FAP and SCR device in the exhaust line, the presence of the oxidation catalytic converter containing platinum to oxidize the NO in NO2 also has drawbacks: noble metals are complex to form on supports, and are an expensive raw material that increases the cost of such a system.
[0018] La régénération peut également se faire de façon cyclique de manière connue en augmentant la teneur en hydrocarbures dans les gaz d'échappement. Toutefois, la réaction qui suit est hautement exothermique et risque d'endommager le matériau catalyseur SCR. En particulier, on a pu se rendre compte que les catalyseurs SCR proposés dans US 2008/0041040 ne sont pas suffisamment résistants aux contraintes thermiques et par conséquent perdent leur efficacité au fil du temps et de leur utilisation.  Regeneration can also be cyclically in a known manner by increasing the hydrocarbon content in the exhaust gas. However, the reaction that follows is highly exothermic and may damage the SCR catalyst material. In particular, it has been realized that the SCR catalysts proposed in US 2008/0041040 are not sufficiently resistant to thermal stresses and therefore lose their effectiveness over time and their use.
[0019] De manière à pallier ces inconvénients, la présente invention a pour but de proposer un dispositif de traitement des gaz d'échappement issus d'un moteur thermique, comportant un filtre à particules constitué d'un matériau poreux pour piéger et oxyder les suies et un catalyseur de réduction sélective des oxydes d'azote déposé sur les faces de sortie des parois du filtre à particules, caractérisé en ce que ledit catalyseur de réduction sélective est choisi parmi ceux du type présentant une surface spécifique d'au moins 65M2/g après vieillissement à 800 °C. In order to overcome these disadvantages, the present invention aims to propose a device for treating exhaust gases from an engine. thermal device, comprising a particulate filter consisting of a porous material for trapping and oxidizing soot and a selective reduction catalyst of the nitrogen oxides deposited on the outlet faces of the walls of the particulate filter, characterized in that said catalyst selective reduction is chosen from those of the type having a specific surface area of at least 65M 2 / g after aging at 800 ° C.
[0020] Ainsi, le matériau catalyseur SCR est choisi pour résister de manière avantageuse aux contraintes thermiques rencontrées lors des régénérations du filtre à particules et être stable thermiquement de sorte que le dispositif de traitement selon l'invention présente toutes les qualités requises pour répondre aux normes de plus en plus sévères.  Thus, the catalyst material SCR is chosen to advantageously withstand the thermal stresses encountered during the regeneration of the particulate filter and be thermally stable so that the treatment device according to the invention has all the qualities required to meet the requirements of the invention. standards increasingly severe.
[0021 ] La surface spécifique du catalyseur reste élevée même après vieillissement c'est à dire après avoir été soumise à des sollicitations hydrothermales à 800 °C.  The specific surface of the catalyst remains high even after aging, that is to say after having been subjected to hydrothermal stresses at 800 ° C.
[0022] De préférence, ledit catalyseur de réduction sélective est choisi parmi ceux du type présentant une surface spécifique d'au moins 65M2/g après vieillissement à 850 °C. De manière encore plus préférée, le catalyseur de réduction sélective est choisi parmi ceux du type présentant une surface spécifique d'au moins 65M2/g après vieillissement à 900 °C. Preferably, said selective reduction catalyst is chosen from those of the type having a specific surface area of at least 65M 2 / g after aging at 850 ° C. Even more preferably, the selective reduction catalyst is selected from those of the type having a surface area of at least 65M 2 / g after aging at 900 ° C.
[0023] On entend par surface spécifique, la surface spécifique B.E.T. déterminée par adsorption d'azote conformément à la norme ASTM D 3663-78 établie à partir de la méthode BRUNAUER-EMMETT-TELLER décrite dans le périodique « The Journal of the American Chemical Society ,60,309 (1938).  By specific surface is meant the specific surface B.E.T. determined by nitrogen adsorption according to ASTM D 3663-78 established from the BRUNAUER-EMMETT-TELLER method described in the periodical "The Journal of the American Chemical Society, 60,309 (1938).
[0024] Ainsi, un matériau catalyseur SCR pour un dispositif selon l'invention peut être choisi parmi les oxydes acides tels que ceux décrits par la société RHODIA, la phase catalytique SCR commerciale à base de Zr-Ti-Si-W-Ce et tout autre matériau catalyseur présentant une surface spécifique d'au moins 65 M2/g après vieillissement à 800°C. Thus, an SCR catalyst material for a device according to the invention may be chosen from acidic oxides such as those described by the company Rhodia, the commercial SCR catalytic phase based on Zr-Ti-Si-W-Ce and any other catalyst material having a surface area of at least 65 M 2 / g after aging at 800 ° C.
[0025] De préférence, l'oxydation des suies dans le dispositif de traitement est favorisée par l'utilisation d'un additif Ce ou Ce-Fe ou Fe introduit dans le carburant qui permet d'abaisser la température de combustion des suies.  Preferably, the oxidation of soot in the treatment device is promoted by the use of an additive Ce or Ce-Fe or Fe introduced into the fuel that lowers the soot combustion temperature.
[0026] Ainsi de manière avantageuse, on propose un dispositif de traitement des gaz d'échappement dans les canaux d'entrée duquel sont retenues les particules et sont ensuite oxydées les suies lors de régénération, les suies étant oxydées en C02 et H20, à une température abaissée à l'aide de l'additif provenant du carburant et déposé sur les suies tandis que sur la paroi du sortie s'effectue la réduction des NOx par l'ammoniaque sur le catalyseur SCR déposé sur ces parois filtrantes. Thus advantageously, there is provided an exhaust gas treatment device in the inlet channels from which the particles are retained and are the soot is then oxidized during regeneration, the soot being oxidized to CO 2 and H 2 O, at a temperature lowered by means of the additive from the fuel and deposited on the soot while on the wall of the outlet the reduction of NOx by ammonia on the SCR catalyst deposited on these filtering walls.
[0027] De manière avantageuse, de l'urée ou de l'ammoniac peut être introduit en amont du dispositif de traitement selon l'invention. Advantageously, urea or ammonia may be introduced upstream of the treatment device according to the invention.
[0028] De préférence, on met en place en amont dudit dispositif de traitement dans la ligne d'échappement, un catalyseur d'oxydation du CO et des hydrocarbures.  Preferably, it is put upstream of said treatment device in the exhaust line, a CO oxidation catalyst and hydrocarbons.
[0029] Ainsi, on introduit l'urée dans la ligne d'échappement en aval du catalyseur d'oxydation du CO et des hydrocarbures et en amont du dispositif de traitement selon l'invention. Selon une variante de l'invention, on prévoit de préférence un catalyseur de décomposition de l'urée en ammoniac déposé sur les canaux d'entrée du filtre à particules du dispositif de traitement selon l'invention. On décompose ainsi l'urée dans la paroi du filtre à particule ce qui permet d'éviter d'avoir recours à un mixeur en amont du dispositif Filtre /SCR.  Thus, urea is introduced into the exhaust line downstream of the oxidation catalyst of CO and hydrocarbons and upstream of the treatment device according to the invention. According to a variant of the invention, a catalyst for decomposing urea ammonia deposited on the inlet channels of the particle filter of the treatment device according to the invention is preferably provided. The urea is thus decomposed in the wall of the particle filter, which makes it possible to avoid using a mixer upstream of the Filter / SCR device.
[0030] En variante, on peut injecter de l'ammoniac directement dans la ligne d'échappement.  Alternatively, one can inject ammonia directly into the exhaust line.
[0031 ] L'invention concerne également un véhicule automobile comportant un tel dispositif de traitement.  The invention also relates to a motor vehicle comprising such a treatment device.
[0032] On décrira maintenant l'invention plus en détails en référence aux exemples ci-après. The invention will now be described in more detail with reference to the examples below.
[0033] Exemple 1 - dispositif selon l'état de la technique  Example 1 - Device according to the state of the art
[0034] Dans l'exemple 1 , on fabrique un dispositif de traitement selon l'état antérieur décrit dans US 2008/004140, un catalyseur SCR selon ce document étant déposé sur la face de sortie d'un filtre à particules (FAP).  In Example 1, a processing device is produced according to the prior state described in US 2008/004140, an SCR catalyst according to this document being deposited on the outlet face of a particulate filter (FAP).
[0035] Après calcination à 500 °C, la composition du catalyseur SCR dans le filtre à particule en SiC de 400 cpsi est la suivante :  After calcination at 500 ° C., the composition of the SCR catalyst in the SiC particle filter of 400 cpsi is as follows:
sur les canaux d'entrée du FAP : dépôt de 98grs/l de FAP d'un oxyde de titane anatase, sur les canaux de sortie du FAP : dépôt de 101 grs/l de FAP d'un catalyseur SCR commercial à base de 2% poids de fer déposé sur une zéolithe ferriérite. on FAP input channels: 98 g / l FAP deposition of anatase titanium oxide, on the exit channels of the FAP: deposition of 101 grs / l of FAP of a commercial SCR catalyst based on 2% by weight of iron deposited on a zeolite ferrierite.
Exemple 2 - Dispositif selon l'invention Example 2 - Device according to the invention
[0036] Dans l'exemple 2 est réalisé un dispositif selon l'invention par dépôt d'une phase catalytique SCR commerciale à base de Zr-Ti-Si-W-Ce sur un filtre à particules en SiC de 400cpsi. Cette phase active est déposée sur la paroi de sortie des canaux du filtre à particule par une technique conventionnelle d'enduction par trempage, soufflage, séchage et calcination à 500 °C. In Example 2 is carried out a device according to the invention by deposition of a commercial SCR catalytic phase based on Zr-Ti-Si-W-Ce on a 400cpsi SiC particle filter. This active phase is deposited on the outlet wall of the particle filter channels by conventional dipping, blowing, drying and calcining at 500 ° C.
[0037] Après calcination à 500 °C, la composition du catalyseur selon l'invention est la suivante : After calcination at 500 ° C, the composition of the catalyst according to the invention is as follows:
- sur les canaux d'entrée du FAP : pas de dépôt de catalyseur ou d'oxyde  - on the FAP inlet channels: no catalyst or oxide deposits
- sur les canaux de sortie du FAP : dépôt de 202grs/l de FAP d'un catalyseur SCR commercial à base d'un oxyde Zr-Ti-Si-W-Ce  - on the FAP outlet channels: deposition of 202grs / l of FAP of a commercial SCR catalyst based on a Zr-Ti-Si-W-Ce oxide
Exemple 3 Vieillissement des dispositifs des exemples 1 et 2 Example 3 Aging Devices of Examples 1 and 2
[0038] Préalablement à l'évaluation des performances en réduction des oxydes d'azote par l'ammoniac les dispositifs des exemples 1 et 2 sont vieillis sous flux d'air contenant 10% d'eau pendant 25heures à 850 °C.  Prior to the evaluation of the performance in reducing nitrogen oxides by ammonia devices of Examples 1 and 2 are aged under air flow containing 10% water for 25 hours at 850 ° C.
[0039] Ce traitement hydrothermal est appliqué pour représenter les vieillissements hydrothermaux que les dispositifs FAP-catalyseurs subissent lors des régénérations des filtres à particules dans les conditions réelles sur véhicule. This hydrothermal treatment is applied to represent the hydrothermal aging that the FAP-catalyst devices undergo during regeneration of particulate filters under real conditions on the vehicle.
[0040] Après vieillissement les dispositifs et plus précisément la partie catalyseur du dispositif sont référencés  After aging the devices and more specifically the catalyst part of the device are referenced
Catalyseur A pour le catalyseur de l'exemple 1 Vieilli à 850 °C  Catalyst A for the catalyst of Example 1 aged at 850 ° C.
Catalyseur B pour le catalyseur de l'invention décrit à l'exemple 2 Vieilli à 850 °C Catalyst B for the catalyst of the invention described in Example 2 aged at 850 ° C.
[0041 ] Les surfaces spécifiques BET sont pour les catalyseurs A et B respectivement de 55M2/g et de 67M2/G. Exemple 4 Evaluation des performances des catalyseurs A et B décrits dans les exemples 1 , 2 et 3 BET specific surfaces are for catalysts A and B respectively of 55M 2 / g and 67M 2 / G. Example 4 Evaluation of the Performance of Catalysts A and B Described in Examples 1, 2 and 3
[0042] Les catalyseurs A et B sont évalués sur banc de gaz synthétique dans les conditions suivantes :  The catalysts A and B are evaluated on a synthetic gas bench under the following conditions:
[0043] Composition du mélange réactionnel :  Composition of the reaction mixture:
. NO x: 400 ppm ( 50% N0 + 50% NO2)  . NO x: 400 ppm (50% N0 + 50% NO2)
. C½ : 8 % . C½: 8%
. H2O : 10 % . H 2 O: 10%
. NHs/NOx : 1  . NHs / NOx: 1
. Complément à 100% par de l'azote  . 100% supplement with nitrogen
Vitesse Volumétrique Horaire (VVH) sur la carotte de FAP 1 'X3'= : 30 000 h"1 Hourly Volumetric Velocity (VVH) on the FAP core 1 'X3' =: 30 000 h "1
Température : programmation de 180 à 500 °C avec une vitesse de montée en température de 5 °C par minute. Temperature: programming from 180 to 500 ° C with a temperature rise rate of 5 ° C per minute.
La composition des gaz en sortie du réacteur catalytique est mesurée par - The composition of the gases leaving the catalytic reactor is measured by -
Chimiluminescence pour NO et NO2 Chemiluminescence for NO and NO2
Infrarouge pour le N2O  Infrared for N2O
Absorption spectroscopique pour NH3  Spectroscopic absorption for NH3
[0044] Les performances en conversion des NOx des catalyseurs A et B sont reportées dans le tableau 1 :  The NOx conversion performance of the catalysts A and B are reported in Table 1:
Tableau 1 : Conversion des NOx en fonction de la température pour les catalyseurs A et B [0045] Les résultats reportés tableau 1 montrent que le catalyseur B selon l'invention est plus performant en réduction des NOx que le catalyseur A selon l'art antérieur. Table 1: NOx Conversion as a Function of Temperature for Catalysts A and B The results reported in Table 1 show that the catalyst B according to the invention is more efficient in reducing NOx than the catalyst A according to the prior art.

Claims

REVENDICATIONS
1. Dispositif de traitement des gaz d'échappement issus d'un moteur thermique, comportant un filtre à particules constitué d'un matériau poreux pour piéger et oxyder les suies et un catalyseur de réduction sélective des oxydes d'azote déposé sur les faces de sortie des parois du filtre à particules, caractérisé en ce que ledit catalyseur de réduction sélective est choisi parmi ceux du type présentant une surface spécifique d'au moins 65M2/g après vieillissement à 800 °C. 1. Apparatus for treating exhaust gases from a heat engine, comprising a particle filter consisting of a porous material for trapping and oxidizing soot and a selective reduction catalyst of nitrogen oxides deposited on the faces of leaving the walls of the particulate filter, characterized in that said selective reduction catalyst is chosen from those of the type having a specific surface area of at least 65M 2 / g after aging at 800 ° C.
2. Dispositif de traitement selon la revendication 1 , caractérisé en ce que le catalyseur de réduction sélective est choisi parmi ceux du type présentant une surface spécifique d'au moins 65M2/g après vieillissement à 850 °C. 2. Treatment device according to claim 1, characterized in that the selective reduction catalyst is selected from those of the type having a specific surface area of at least 65M 2 / g after aging at 850 ° C.
3. Dispositif de traitement selon la revendication 1 , caractérisé en ce que le catalyseur de réduction sélective est choisi parmi ceux du type présentant une surface spécifique d'au moins 65M2/g après vieillissement à 900 °C. 3. Treatment device according to claim 1, characterized in that the selective reduction catalyst is selected from those of the type having a specific surface area of at least 65M 2 / g after aging at 900 ° C.
4. Dispositif de traitement selon l'une des revendications 1 à 3, caractérisé en ce que le matériau catalyseur SCR est une phase catalytique SCR commerciale à base de Zr-Ti-Si-W-Ce. 4. Treatment device according to one of claims 1 to 3, characterized in that the catalyst material SCR is a commercial SCR catalytic phase based on Zr-Ti-Si-W-Ce.
5. Dispositif de traitement selon l'une des revendications 1 à 4, caractérisé en ce que l'oxydation des suies est favorisée à l'aide d'un additif Ce ou Ce-Fe ou Fe introduit dans le carburant qui permet d'abaisser la température de combustion des suies. 5. Treatment device according to one of claims 1 to 4, characterized in that the oxidation of soot is promoted with the aid of an additive Ce or Ce-Fe or Fe introduced into the fuel that allows to lower the soot combustion temperature.
6. Dispositif de traitement selon l'une des revendications 1 à 5, caractérisé en ce qu'un catalyseur d'oxydation du CO et des hydrocarbures est mis en place en amont dudit dispositif de traitement dans la ligne d'échappement. 6. Treatment device according to one of claims 1 to 5, characterized in that a CO oxidation catalyst and hydrocarbons is placed upstream of said treatment device in the exhaust line.
7. Dispositif de traitement selon l'une des revendications 1 à 6, caractérisé en ce qu'on introduit de l'urée dans la ligne d'échappement en amont du dispositif de traitement, un catalyseur de décomposition de l'urée en ammoniac étant déposé sur les canaux d'entrée du filtre à particules dudit dispositif de traitement. 7. Treatment device according to one of claims 1 to 6, characterized in that urea is introduced into the exhaust line upstream of the treatment device, a decomposition catalyst of urea ammonia being deposited on the inlet channels of the particle filter of said treatment device.
8. Dispositif de traitement selon l'une des revendications 1 à 6, caractérisé en ce qu'on injecte de l'ammoniac directement dans la ligne d'échappement. 8. Treatment device according to one of claims 1 to 6, characterized in that ammonia is injected directly into the exhaust line.
9. Véhicule automobile caractérisé en ce qu'il comporte un dispositif de traitement des gaz d'échappement selon l'une des revendications 1 à 8. 9. Motor vehicle characterized in that it comprises an exhaust gas treatment device according to one of claims 1 to 8.
EP10785156A 2009-11-04 2010-10-21 Device for treating exhaust gases from a vehicle comprising a heat engine Withdrawn EP2496801A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR0957784A FR2952123B1 (en) 2009-11-04 2009-11-04 DEVICE FOR TREATING EXHAUST GASES OF A VEHICLE COMPRISING A THERMAL ENGINE
PCT/FR2010/052249 WO2011055053A1 (en) 2009-11-04 2010-10-21 Device for treating exhaust gases from a vehicle comprising a heat engine

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EP2496801A1 true EP2496801A1 (en) 2012-09-12

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US8722000B2 (en) 2011-03-29 2014-05-13 Basf Corporation Multi-component filters for emissions control
FR2992028B1 (en) * 2012-06-19 2014-07-11 Peugeot Citroen Automobiles Sa METHOD FOR USING PARTICLE FILTER FOR HEAT ENGINES

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EP1177032A1 (en) * 1999-05-07 2002-02-06 Renault Device for purifying exhaust gases for an internal combustion engine
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WO2011055053A1 (en) 2011-05-12
FR2952123B1 (en) 2012-02-24

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