WO2015074698A1 - Filtre à particules configuré sous la forme d'un filtre à parois - Google Patents

Filtre à particules configuré sous la forme d'un filtre à parois Download PDF

Info

Publication number
WO2015074698A1
WO2015074698A1 PCT/EP2013/074345 EP2013074345W WO2015074698A1 WO 2015074698 A1 WO2015074698 A1 WO 2015074698A1 EP 2013074345 W EP2013074345 W EP 2013074345W WO 2015074698 A1 WO2015074698 A1 WO 2015074698A1
Authority
WO
WIPO (PCT)
Prior art keywords
substrate
porosity
zone
filter
particle filter
Prior art date
Application number
PCT/EP2013/074345
Other languages
German (de)
English (en)
Inventor
Klaus Schrewe
Simon Steigert
Original Assignee
Hjs Emission Technology Gmbh & Co. Kg
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 Hjs Emission Technology Gmbh & Co. Kg filed Critical Hjs Emission Technology Gmbh & Co. Kg
Priority to CN201380081133.XA priority Critical patent/CN105813715A/zh
Priority to PCT/EP2013/074345 priority patent/WO2015074698A1/fr
Publication of WO2015074698A1 publication Critical patent/WO2015074698A1/fr

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
    • B01D46/24—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies
    • B01D46/2403—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies characterised by the physical shape or structure of the filtering element
    • B01D46/2418—Honeycomb filters
    • B01D46/2425—Honeycomb filters characterized by parameters related to the physical properties of the honeycomb structure material
    • B01D46/24491—Porosity
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
    • B01D46/24—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies
    • B01D46/2403—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies characterised by the physical shape or structure of the filtering element
    • B01D46/2418—Honeycomb filters
    • B01D46/2425—Honeycomb filters characterized by parameters related to the physical properties of the honeycomb structure material
    • B01D46/2429—Honeycomb filters characterized by parameters related to the physical properties of the honeycomb structure material of the honeycomb walls or cells
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
    • B01D46/24—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies
    • B01D46/2403—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies characterised by the physical shape or structure of the filtering element
    • B01D46/2418—Honeycomb filters
    • B01D46/2425—Honeycomb filters characterized by parameters related to the physical properties of the honeycomb structure material
    • B01D46/24492—Pore diameter
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
    • B01D46/24—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies
    • B01D46/2403—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies characterised by the physical shape or structure of the filtering element
    • B01D46/2418—Honeycomb filters
    • B01D46/2451—Honeycomb filters characterized by the geometrical structure, shape, pattern or configuration or parameters related to the geometry of the structure
    • B01D46/2474—Honeycomb filters characterized by the geometrical structure, shape, pattern or configuration or parameters related to the geometry of the structure of the walls along the length of the honeycomb
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
    • B01D46/24—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies
    • B01D46/2403—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies characterised by the physical shape or structure of the filtering element
    • B01D46/2418—Honeycomb filters
    • B01D46/2451—Honeycomb filters characterized by the geometrical structure, shape, pattern or configuration or parameters related to the geometry of the structure
    • B01D46/2482—Thickness, height, width, length or diameter
    • 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
    • B01D53/944—Simultaneously removing carbon monoxide, hydrocarbons or carbon making use of oxidation catalysts
    • 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
    • F01N3/022—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 characterised by specially adapted filtering structure, e.g. honeycomb, mesh or fibrous
    • F01N3/0222—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 characterised by specially adapted filtering structure, e.g. honeycomb, mesh or fibrous the structure being monolithic, e.g. honeycombs
    • 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
    • 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
    • F01N3/2066—Selective catalytic reduction [SCR]
    • 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
    • F01N3/2825—Ceramics
    • F01N3/2828—Ceramic multi-channel monoliths, e.g. honeycombs
    • 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
    • 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
    • B01D2255/9205—Porosity
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2258/00—Sources of waste gases
    • B01D2258/01—Engine exhaust gases
    • B01D2258/012—Diesel engines and lean burn gasoline engines
    • 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
    • F01N2330/06—Ceramic, e.g. monoliths
    • 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
    • F01N2330/30—Honeycomb supports characterised by their structural details
    • F01N2330/32—Honeycomb supports characterised by their structural details characterised by the shape, form or number of corrugations of plates, sheets or foils
    • 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
    • F01N2330/60—Discontinuous, uneven properties of filter material, e.g. different material thickness along the longitudinal direction; Higher filter capacity upstream than downstream in same housing
    • 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

  • Particle filter designed as a wall-flow filter
  • the invention relates to a designed as a wall-flow filter particulate filter for removing entrained in the exhaust gas of an internal combustion engine soot particles, which particulate filter has a porous substrate with a plurality of filter walls enclosed by filter walls.
  • a particle filter is turned on. This serves to remove entrained in the exhaust gas of the internal combustion engine particles, in particular of soot particles.
  • the particulate filters are designed as full filters.
  • Such full filters are wall-flow filters, ie: filters in which the medium to be filtered - here: the particles, and indeed the soot particles entraining exhaust gas - must flow through a filter wall to get from the upstream side of the substrate on the downstream side - the clean side.
  • the substrate of such a particle filter comprises a multiplicity of filter channels which run parallel to one another and are enclosed by filter walls.
  • a ceramic material is often used.
  • the filter channels are arranged side by side in the manner of honeycombs and each separated by a filter wall.
  • the filter channels are alternately closed on the upstream side and downstream side.
  • the cross sections of the inlet and outlet channels can be symmetrical or asymmetrical.
  • Particle filters with other filter channel geometry are also known from sintered metal materials.
  • Such particulate filters are designed for operation of the exhaust gas purification system, so that the exhaust backpressure does not increase too much as a result of this, even with increasing accumulation of soot. For this reason, it is necessary that such a substrate is regenerated with sufficient soot loading.
  • a regeneration of the accumulated soot is oxidized, which is also addressed as a controlled Rußabbrand.
  • Such regeneration can passively and thus automatically or actively upon reaching a certain temperature of the soot triggered by temperature, done.
  • the soot accumulated on the upstream side NO 2 is supplied, whereby an oxidation of the soot already takes place at lower temperatures and thus no additional increase in temperature must be made.
  • such a particle filter or its substrate is designed that they have a relatively small pore size of typically 5 ⁇ to 15 ⁇ and a porosity of usually significantly less than 50%.
  • the substrate is designed so that, starting from an unloaded substrate, the filtration process sets as quickly as possible to a surface filtration. Before a surface filtration takes place at least to a significant degree, the pores in the filter walls must have added something with soot, whereby the effective porosity compared to that of the substrate is further reduced. During the duration of the depth filtering, the desired separation efficiency of more than 98% can not yet be realized with such filters. Therefore, it is endeavored to design such particle filters so that they quickly reach the state of their intended surface filtration.
  • soot emission of an internal combustion engine is reduced by 50% or even only 20% to 25%.
  • Partial filters have a maximum nominal degree of separation of the desired order of magnitude. This means that such filters can absorb the proportion of the entrained in the exhaust gas of an internal combustion engine particles, in particular soot particles.
  • Partial filters can be designed as a wall-flow filter. In such a case, the substrate used for a full filter is used and one or more, usually a plurality of bypass channels are formed by different measures. The bypass channels represent a flow path from the upstream side of the substrate to the downstream side, without having to flow through a filter wall of the exhaust gas. Such a bypass is established by connecting a outflow-closed filter channel with one or more outflow-side open filter channels.
  • the flow-through cross-sectional area of the bypass flow path is designed so that a certain portion of the exhaust gas flow through this unfiltered.
  • the degree of separation that can be achieved with such a sub-filter is determined.
  • Particulate filters which are designed as wall-flow filters with a channel structure, accumulate the soot entrained in the exhaust gas essentially in the filter channels sealed off on the outflow side. With soot accumulation, it can be observed that as the depth of a filter channel increases, soot build-up increases. Thus, the soot load increases successively from the inlet side of a filter channel to its downstream closure.
  • the present in the region of the downstream end of the particulate filter and relative to the input side relatively larger soot mass can lead to thermal problems in the downstream end zone of the particulate filter or its substrate in a regeneration. This can overheat in this zone, which can damage or even destroy the particulate filter. This is especially true for particulate filters whose substrates are made of a ceramic material, such as a cordierite material.
  • the invention is therefore the object of developing a configured as a wall-flow filter with a channel structure particulate filter in such a way that the risk of overheating caused by a regeneration in the Substratendzone is effectively avoided.
  • a generic particle filter mentioned in the introduction in which the substrate has at least two substrate zones of different porosity located behind one another in the throughflow direction of the exhaust gas through the substrate.
  • the substrate and thus the filter walls enclosing the filter channels have at least two zones arranged one behind the other in the flow direction of the exhaust gas through the substrate.
  • different porosity The design of a substrate with zones of different porosity requires that in these zones a different flow behavior of the exhaust gas through the filter walls can be adjusted.
  • the drawback with respect to a sometimes too strong accumulation of carbon black in the downstream end zone of the substrate in the filter channels closed in this direction can be effectively counteracted with the concept discussed in the background discussed in the introduction. This is achieved with the fact that, in an end zone of the substrate arranged downstream, it is provided with a lower porosity than in the main flow accumulation zone arranged upstream of it.
  • the lower porosity in such an end zone means that the exhaust gas entraining the soot particles increasingly flows through the one or more upstream zones of higher porosity and thus entrained soot particles corresponding to the favored flow path in this or these zones on the upstream filter wall is deposited. In this way, particulate filter damage by undesired overheating of the exit end zone during regeneration can be effectively avoided.
  • a substrate initially produced with a uniform porosity if this has not already been provided with appropriate porosity zoning during production, by coating the one or more zones of the substrate which are to have a lower porosity than other porosity zones.
  • Such a coating is preferably carried out as a surface-enlarging coating, typically by applying a so-called washcoat.
  • washcoats are well known.
  • washcoats are conventionally used to increase the substrate surface area of catalysts. It is understood that the porosity of a zone can be easily adjusted by coating once or more with one and the same washcoat or with different washcoats.
  • an input zone may have a lower porosity than the downstream thereof. Adjacent adjacent porosity zone.
  • a porosity zone over the entire cross-sectional area of the substrate.
  • a porosity zone which differs with regard to its porosity from an adjacent porosity zone, is restricted to only a partial region of the cross-sectional area of the substrate.
  • this concept can also be used to promote an even distribution of soot deposition across the cross section of the substrate, when the substrate is asymmetrically flowed through the exhaust gas to be cleaned. For filter assemblies made of individual segments, this can be implemented particularly easily.
  • a porosity zoning of a particle filter designed as a wall-flow filter can be applied equally to full filters as to partial filters.
  • this concept is of particular interest for particulate filters designed as wall-flow filters, since according to a preferred embodiment they have a substrate with a high porosity, in particular a porosity of more than 50%.
  • This high porosity which is preferably between about 60 and 70%, is advantageously accompanied by a relatively large average pore size, specifically between 15 ⁇ m and 30 ⁇ m. According to an advantageous development, a pore size of not more than 25 ⁇ is sought.
  • Such a substrate which may be made of a silicon carbide material, is particularly well suited to carry out the porosity zoning by applying one or more surface-enhancing coatings, in particular in the manner of a washcoat, on the basis of a substrate of uniform porosity. It makes sense to adjust the washcoat used so that the porosity of the substrate is reduced by about 5% to 10% in a coating process. This allows the formation of a sufficient for the purposes mentioned porosity contrast between adjacent porosity zones of the substrate. It may well be provided that in a first step, the substrate is coated with a washcoat as a whole, in order then to form in subsequent steps, compared to the initially set uniform porosity porosity zones with reduced porosity. When a washcoat is applied, the highly porous substrate which is preferably used is also coated in its pores, so that the reduction of the porosity is accompanied by a certain reduction in the pore size.
  • washcoat coating used for porosity zoning of the substrate can also be used as a surface-enlarging carrier for a catalytic coating. This may be, for example, an oxidation-catalytic coating.
  • Such a substrate which is wholly or partially equipped with a washcoat, to have a catalytic coating effective for NO x reduction, for example such that a selective catalytic reduction of the nitrogen oxides according to the so-called SCR method is possible .
  • a catalytic coating effective for NO x reduction for example such that a selective catalytic reduction of the nitrogen oxides according to the so-called SCR method is possible
  • This zone which then acts as a hydrolysis catalyst, supports the digestion of urea droplets entrained in the exhaust gas as a reducing agent precursor in order to liberate the NH 3 contained therein as a reducing agent. This is needed for the NO x reduction taking place downstream of the substrate at the SCR catalytic coating.
  • the degree of separation of such a particle filter is also determined by the filter channel density.
  • This feature also referred to as cell density, is preferably between about 100 cpsi and 350 cpsi, in particular between about 180 cpsi and about 225 cpsi (cpsi: cells per square inch).
  • cpsi cells per square inch.
  • Especially effective Particle Filters have about 200 cpsi, considering the design criteria already mentioned above.
  • the filter channel density for the purpose of the substrate can be considered. If the filter channel density is lower, it has been shown that the flow velocity through the filter walls is relatively high, thus reducing the depth filtration desired in the design of such a particle filter and thus decreasing the separation efficiency. In addition, then the cross-sectional area of the bypass flow path is relatively large. At higher cell density, the cross-sectional area of the bypass pathway is relatively small. In addition, it has been shown that a depth filtration in the filter walls then takes place only subordinate, which leads to too rapid Rußakkumulation alone on the surface.
  • FIG. 1 shows a schematic longitudinal section through a filter channel of FIG Variety of such filter channels having substrate of a particulate filter according to the invention with soot-loaded filter walls,
  • FIG. 2 shows a schematic longitudinal section through a filter channel of a
  • FIG 3 shows an exhaust gas purification unit provided with two catalytically coated particle filter elements designed as wall-flow filters.
  • a made of a highly porous silicon carbide material substrate 1 has a plurality of mutually parallel, enclosed by filter walls filter channels.
  • the particulate filter is designed as a sub-filter, which is why a first plurality of filter channels is closed downstream in this embodiment, while a second plurality of channels is unlocked and thus provide bypass fürströmwegsamkeiten.
  • the porosity of the silicon carbide material from which the substrate 1 is made is about 65% in the illustrated embodiment.
  • FIG. 1 shows in a longitudinal section a filter channel 3 enclosed by filter walls 2, 2.1, 2.2.
  • the filter channel 3 is closed downstream by a closing body 4 which forms a stopper with respect to the filter channel 3.
  • the adjacent to this filter channel 3 filter channels are not closed in the illustrated embodiment.
  • the particulate filter formed from the substrate 1 is a particulate filter.
  • the stopper 4 and with this all other, one filter channel downstream occlusive stopper has been used only after a plurality of porosity zones have been established over the longitudinal extent of the substrate.
  • three porosity zones PL P 2 , P3 are provided. These are arranged one behind the other in the flow direction of the exhaust gas through the substrate 1, as represented by the block arrows.
  • the three porosity zones P 2 , P 3 by correspondingly reducing the original porosity of the substrate 1 after its production.
  • the substrate 1 has been coated overall with a washcoat in a first step. In this and also in the subsequent coating processes, it has a positive effect that the sealing plugs 4 are not yet installed.
  • the washcoat used is a per se known, which conventionally serves as a carrier for a catalytic coating.
  • the substrate 1 it is primarily the surface-enlarging properties of the applied washcoat that are used to reduce the porosity.
  • the porosity in the central porosity zone P2 has been adjusted. Compared to the original porosity this is reduced by about 7%.
  • the porosity zone P 3 - the porosity is again reduced by about 7% by a second washcoat coating process.
  • the porosity zone P1 in Figure 1 the porosity is also reduced by a second washcoat coating process from the porosity in the porosity zone P2.
  • the same washcoat so that the substrate 1 in the Porosticianszonen P1, P 3 having a porosity of about 51% and in the Porosticianszone P2 of about 58%.
  • the exhaust gas preferably flows through the porosity zone P 2 .
  • the washcoat present in the porosity zones P2 and P3 is equipped with a selectively reducing catalytic coating.
  • the substrate 1 of the particulate filter works in the zones P 2 and P 3 in the manner of an SCR catalyst in the presence of ammonia as a reducing agent in addition to its filtering function.
  • the washcoat present in the porosity zone P1 is provided with a hydrolysis-causing coating. This serves to accelerate a hydrolysis of fine urea droplets entrained in the exhaust gas, in order to use as the reduction catalyst for the SCR catalysis. release the required NH 3 .
  • the substrate 1 of the particle part filter in addition to its actual filter function and the function of an SCR catalyst is assigned. It is understood that urea is injected into the exhaust stream upstream of the substrate for SCR catalysis.
  • soot deposits in the porosity zone Pi. Due to the lower flow resistance in the porosity zone P 2 , most of the amount of soot in the porosity zone P 2 is accumulated. This is especially true with respect to the thickness of the accumulated soot. Since the porosity zone P 2, based on the longitudinal extent of the substrate 1 is the longest zone and occupies about 70% of the length of the substrate 1, this contributes to the fact that most amount of soot is accumulated in this porosity zone P 2 .
  • FIG. 2 shows a representation corresponding to that of FIG. 1 with a substrate of homogeneous porosity over its longitudinal extent according to the concept known from the prior art.
  • the filter channel F shown in FIG. 2 has a soot charge R, which increases successively to the closure body V.
  • This soot accumulation which is typical for conventional particulate filter substrates, illustrates the risk of overheating during regeneration in the downstream end region due to the relatively large amount of soot present in the end zone. The reason for this is simply the relatively large amount of soot present in this area, which further increases the regeneration temperature and, above all, the regeneration process lasts longer than in those areas in which only a smaller amount of soot accumulation has taken place.
  • FIG. 3 shows an exhaust-gas cleaning unit with the substrate 1 forming a particle-part filter.
  • a housing 7 with the substrate 1 is another substrate 8, also formed as a particle filter.
  • the substrate 8 is also one as described for the substrate 1.
  • the substrate 8 has only two porosity zones P 4 , P 5 .
  • the porosity zones P 4 , P 5 correspond to the porosity zones P 2 , P 3 of the substrate 1.
  • the washcoat coating of the substrate 8 is equipped with an oxidation-catalytic coating.
  • This is used to remove hydrocarbons and carbon monoxide from the exhaust stream and to generate NO 2 from the entrained in the exhaust NO.
  • On the output side with respect to the substrate 8 one desires an exhaust gas stream with a NO: NO 2 ratio of 1: 2 to 2: 1.
  • NO: NO 2 ratio promotes SCR catalysis in the substrate 1.
  • the reduced porosity zone P5 in the substrate 8 serves the purpose of preventing it from overheating during regeneration.
  • an injection device 9 for supplying urea as a reducing agent precursor in liquid form.
  • the injection device 9 is added in liquid form led urea atomized, which is digested at the latest on impact on the hydrolysis catalytic coating in the porosity zone Pi of the substrate 1.
  • pore sizes are indicated in the context of these statements, this means the mean pore size is regularly meant.
  • the bandwidth of the pore size preferably corresponds to a standard deviation of not more than 70%.
  • Both purification stages of the exhaust gas purification unit described with reference to FIG. 3 can be constructed from one or more filter substrates connected in series.
  • a structure of a total substrate of a plurality of individual substrates is useful for regeneration due to the then relatively short length of the individual substrates in the flow direction of the exhaust gas, since thermally induced damage is effectively avoided.
  • the individual substrates are arranged in cascade to one another. In the case of such a cascade-like configuration, it is expedient that each individual substrate has a zone of reduced porosity in an end region, as described in the exemplary embodiments.
  • turbulence-generating internals can be provided, for example, designed as a turbulence grid.
  • the partial particle filter designed as a wall-flow filter as a substrate for a catalytic coating to be applied thereto has a very large compared to full filters for the application of the washcoat and thus for the catalytic coating due to the relatively high porosity and relatively large pore size have achievable surface.
  • the sub-filter ensures that the pore volume is coated catalytically.
  • a substrate provides, in a compact space, a particularly large catalyst area compared to a surface designed for pure catalysts.
  • the exhaust gas purification concept has been described in the embodiments based on the purification of the exhaust gases of a diesel engine, such as a diesel engine. Likewise, this concept can also be used to clean the exhaust gases of gasoline engines.
  • the described exhaust gas purification units can also be addressed as four-way exhaust gas purification units or four-way catalysts.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Geometry (AREA)
  • Physics & Mathematics (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Health & Medical Sciences (AREA)
  • Ceramic Engineering (AREA)
  • Toxicology (AREA)
  • Biomedical Technology (AREA)
  • Environmental & Geological Engineering (AREA)
  • Analytical Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Filtering Materials (AREA)
  • Exhaust Gas After Treatment (AREA)
  • Processes For Solid Components From Exhaust (AREA)

Abstract

L'invention concerne un filtre à particules configuré sous la forme d'un filtre à parois et servant à éliminer les particules de suie entraînées dans le gaz d'échappement d'un moteur à combustion interne, en particulier d'un moteur diesel. Le filtre à particules comprend un substrat poreux (1) muni d'une pluralité de canaux filtrants (3) bordés par des parois filtrantes (2). Le substrat (1) comporte au moins deux zones de substrat Ρ1, P2, P3 de porosité différente situées les unes derrière les autres dans le sens de l'écoulement du gaz d'échappement à travers le substrat (1).
PCT/EP2013/074345 2013-11-21 2013-11-21 Filtre à particules configuré sous la forme d'un filtre à parois WO2015074698A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
CN201380081133.XA CN105813715A (zh) 2013-11-21 2013-11-21 设计为壁式流动过滤器的颗粒过滤器
PCT/EP2013/074345 WO2015074698A1 (fr) 2013-11-21 2013-11-21 Filtre à particules configuré sous la forme d'un filtre à parois

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/EP2013/074345 WO2015074698A1 (fr) 2013-11-21 2013-11-21 Filtre à particules configuré sous la forme d'un filtre à parois

Publications (1)

Publication Number Publication Date
WO2015074698A1 true WO2015074698A1 (fr) 2015-05-28

Family

ID=49679499

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2013/074345 WO2015074698A1 (fr) 2013-11-21 2013-11-21 Filtre à particules configuré sous la forme d'un filtre à parois

Country Status (2)

Country Link
CN (1) CN105813715A (fr)
WO (1) WO2015074698A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3574983A3 (fr) * 2015-06-28 2020-02-26 Johnson Matthey Public Limited Company Filtre catalytique à écoulement sur paroi ayant une membrane
US11203958B2 (en) 2015-09-30 2021-12-21 Johnson Matthey Public Limited Company Gasoline particulate filter

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP6729356B2 (ja) * 2016-12-27 2020-07-22 株式会社デンソー 多孔質ハニカムフィルタ

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080072551A1 (en) * 2002-10-28 2008-03-27 Bilal Zuberi Highly porous mullite particulate filter substrate
US20100003172A1 (en) * 2006-07-21 2010-01-07 Dow Global Technologies Inc. Zone catalyzed soot filter
US20120230881A1 (en) * 2011-03-11 2012-09-13 Thorsten Rolf Boger HONEYCOMB FILTERS FOR REDUCING NOx AND PARTICULATE MATTER IN DIESEL ENGINE EXHAUST
US20120247092A1 (en) * 2011-03-29 2012-10-04 Basf Corporation Multi-Component Filters For Emissions Control

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080072551A1 (en) * 2002-10-28 2008-03-27 Bilal Zuberi Highly porous mullite particulate filter substrate
US20100003172A1 (en) * 2006-07-21 2010-01-07 Dow Global Technologies Inc. Zone catalyzed soot filter
US20120230881A1 (en) * 2011-03-11 2012-09-13 Thorsten Rolf Boger HONEYCOMB FILTERS FOR REDUCING NOx AND PARTICULATE MATTER IN DIESEL ENGINE EXHAUST
US20120247092A1 (en) * 2011-03-29 2012-10-04 Basf Corporation Multi-Component Filters For Emissions Control

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3574983A3 (fr) * 2015-06-28 2020-02-26 Johnson Matthey Public Limited Company Filtre catalytique à écoulement sur paroi ayant une membrane
KR20230112155A (ko) * 2015-06-28 2023-07-26 존슨 맛쎄이 퍼블릭 리미티드 컴파니 막을 가진 촉매 벽 유동형 필터
KR102605894B1 (ko) * 2015-06-28 2023-11-27 존슨 맛쎄이 퍼블릭 리미티드 컴파니 막을 가진 촉매 벽 유동형 필터
US11203958B2 (en) 2015-09-30 2021-12-21 Johnson Matthey Public Limited Company Gasoline particulate filter

Also Published As

Publication number Publication date
CN105813715A (zh) 2016-07-27

Similar Documents

Publication Publication Date Title
EP2558691B1 (fr) Filtre à particules diesel revêtu d'un réducteur catalytique ayant des propriétés améliorées
DE102014004712B4 (de) Wanddurchflusstyp-Abgasreinigungsfilter
DE60020070T2 (de) Katalytischer wabenköper-filter mit porösen trennwänden
EP1728984B1 (fr) Dispositif d'échappement
EP1892396B1 (fr) Système de traitement de gaz d'échappement
DE102015011430A1 (de) Wabenfilter
EP3134622B1 (fr) Systeme modulaire de construction et methode de production pour un module de catalysateur
DE102015011432B4 (de) Wabenfilter
WO2010051983A1 (fr) Réduction de particules avec un catalyseur combiné scr et contre les dégagements de nh3
DE102016003381A1 (de) Abgasreinigungsfilter, Abgasreiniger und Verfahren zur Verwendung des Abgasreinigers
DE10247946A1 (de) Abgasnachbehandlungsanordnung
DE102010021589A1 (de) Abgasnachbehandlungssystem
DE102016111766A1 (de) Katalytischer wandstromfilter, der eine membran aufweist
EP1433519B1 (fr) Procédé de fabrication d'un filtre à particules avec une fonction de stockage des NOx
DE60212245T3 (de) Verfahren und Vorrichtung zur Entfernung von Russpartikeln aus dem Abgas eines Dieselmotors
EP2166203B1 (fr) Dispositif de nettoyage d'un flux de gaz d'échappement d'un moteur à combustion interne d'un véhicule automobile, notamment un véhicule utilitaire
WO2015074698A1 (fr) Filtre à particules configuré sous la forme d'un filtre à parois
DE102014112862A1 (de) Partikelfilter und Verfahren zur Herstellung eines Partikelfilters
WO2015074697A1 (fr) Dispositif d'épuration du gaz d'échappement d'un moteur à combustion interne
EP2659950B1 (fr) Système de traitement postérieur de gaz d'échappement
DE102016002709A1 (de) Wabenstruktur
AT504391B1 (de) Kombiniertes abgasreinigungssystem
EP2699770B1 (fr) Filtre a particules comprenant un revetement catalytique
DE102007063100A1 (de) Abgasnachbehandlungseinrichtung mit mindestens zwei Partikelfiltern
WO2015007306A1 (fr) Filtre à particules configuré sous la forme d'un filtre à écoulement sur paroi comprenant une structure canalaire

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 13798287

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

REG Reference to national code

Ref country code: BR

Ref legal event code: B01A

Ref document number: 112016011506

Country of ref document: BR

122 Ep: pct application non-entry in european phase

Ref document number: 13798287

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 112016011506

Country of ref document: BR

Kind code of ref document: A2

Effective date: 20160520