EP3906110A1 - Procédé de fabrication de filtres de type "wall-flow" catalytiquement actifs - Google Patents

Procédé de fabrication de filtres de type "wall-flow" catalytiquement actifs

Info

Publication number
EP3906110A1
EP3906110A1 EP20700088.6A EP20700088A EP3906110A1 EP 3906110 A1 EP3906110 A1 EP 3906110A1 EP 20700088 A EP20700088 A EP 20700088A EP 3906110 A1 EP3906110 A1 EP 3906110A1
Authority
EP
European Patent Office
Prior art keywords
filter
coating
wall flow
flow filter
catalytically active
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.)
Pending
Application number
EP20700088.6A
Other languages
German (de)
English (en)
Inventor
Astrid Mueller
Meike Antonia GOTTHARDT
Martin Foerster
Stephanie SPIESS
Yannic WEIGL
Carsten HERZOG
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.)
Umicore AG and Co KG
Original Assignee
Umicore AG and 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 Umicore AG and Co KG filed Critical Umicore AG and Co KG
Publication of EP3906110A1 publication Critical patent/EP3906110A1/fr
Pending legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
    • B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
    • 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
    • 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
    • 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
    • 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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/90—Physical characteristics of catalysts
    • B01D2255/915—Catalyst supported on particulate filters
    • B01D2255/9155—Wall flow 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
    • F01N2510/00—Surface coverings
    • F01N2510/06—Surface coverings for exhaust purification, e.g. catalytic reaction
    • F01N2510/068—Surface coverings for exhaust purification, e.g. catalytic reaction characterised by the distribution of the catalytic coatings
    • F01N2510/0682—Surface coverings for exhaust purification, e.g. catalytic reaction characterised by the distribution of the catalytic coatings having a discontinuous, uneven or partially overlapping coating of catalytic material, e.g. higher amount of material upstream than downstream or vice versa
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies

Definitions

  • the present invention is directed to a method for producing particle filters.
  • the particulate filters are commonly used to filter exhaust gases from a combustion process. New filter substrates and their specific use in exhaust gas aftertreatment are also specified.
  • Internal combustion engines in motor vehicles typically contain the harmful gases carbon monoxide (CO) and hydrocarbons (HC), nitrogen oxides (NO x ) and optionally sulfur oxides (SO x ), as well as particles that consist predominantly of soot residues and possibly adhering organic agglomerates. These are referred to as primary emissions.
  • CO, HC and particles are products of the incomplete combustion of the fuel in the engine's combustion chamber.
  • Nitrogen oxides are generated in the cylinder from nitrogen and oxygen in the intake air when the combustion temperatures locally exceed 1400 ° C. Sulfur oxides result from the combustion of organic sulfur compounds, which are always contained in small amounts in non-synthetic fuels.
  • catalytic exhaust gas purification technologies have been developed to remove these emissions, which are harmful to the environment and health, from motor vehicles, the basic principle of which is usually based on the fact that the exhaust gas to be cleaned is passed over a catalytic converter which consists of a flow or wall flow honeycomb body (Wall flow filter) and a catalytically active coating applied thereon and / or therein.
  • the catalyst promotes the chemical reaction of various exhaust gas components with the formation of harmless products such as carbon dioxide and water, and at the same time removes the fine soot particles in the case of a wall flow filter.
  • Wall-flow filters made from ceramic materials have proven particularly useful. These have two end faces and are made up of a large number of parallel channels with a certain length, which are formed by porous walls and extend from one end face to the other. The channels are mutually closed gas-tight on one of the two ends of the filter, so that first channels are formed which are open on the first side of the filter and closed on the second side of the filter, and second channels which are closed on the first side of the filter and open on the second side of the filter. According to the arrangement of the filter in the exhaust gas flow, one of the end faces forms the entry end face and the second end face forms the exit end face for the exhaust gas.
  • the flow channels open on the inlet side form the inlet channels and the flow channels open on the outlet side form the outlet channels.
  • the exhaust gas flowing into the first channels can only leave the filter again via the second channels and must flow through the walls between the first and second channels for this purpose.
  • the material from which the wall flow filters are made has an open-pore porosity. The particles are retained when the exhaust gas passes through the wall.
  • Wall flow filters can be catalytically active.
  • the catalytic activity is achieved by coating the filter with a coating suspension which contains the catalytically active material. Contacting the catalytically active materials with the wall flow filter is referred to in the trade as "coating".
  • the coating takes over the actual catalytic function and often contains storage materials and / or catalytically active metals, which are usually deposited in highly dispersed form on temperature-stable, high-surface metal compounds, in particular oxides.
  • the coating is usually carried out by applying an aqueous suspension of the storage materials and catalytically active components - also called washcoat - on or in the wall of the wall-flow filter. After the suspension has been applied, the support is generally dried and, if appropriate, calcined at elevated temperature.
  • the coating can consist of one layer or be constructed from several layers, which are applied one above the other (multilayer) and / or offset to one another (as zones) on a corresponding filter.
  • the catalytically active material can be applied to the porous walls between the channels (so-called effort coating).
  • this coating can lead to an unacceptable increase in the back pressure of the filter.
  • JPH01-151706 and W02005016497A1 propose to coat a wall flow filter with a catalyst such that the latter penetrates the porous walls (so-called in-wall coating).
  • a zone is understood to mean the presence of a catalytically active material (coating) on or in the wall of the filter over less than the entire length of the wall flow filter.
  • Three-way catalytic converters are used to reduce emissions in stoichiometric combustion engines.
  • Three-way catalysts are well known to those skilled in the art and have been required by law since the 1980s.
  • the actual catalyst mass consists here mostly of a high-surface metal compounds, in particular oxidic carrier material, on which the catalytically active components are separated in the finest distribution.
  • the noble metals of the platinum group, platinum, palladium and / or rhodium are particularly suitable as catalytically active components for the purification of stoichiometrically composed exhaust gases.
  • Suitable substrates are, for example, aluminum oxide, silicon dioxide, titanium oxide, zirconium oxide, cerium oxide and their mixed oxides and zeolites.
  • three-way catalysts also contain oxygen-storing components. These include cerium / zirconium mixed oxides, which may contain lanthanum oxide, praseodymium oxide and / or yttrium oxide. Zoned and multi-layer systems with three-way activity are now known (US8557204; US8394348). If such a three-way catalytic converter is located on or in a particle filter, one speaks of a cGPF (catalyzed gasoline particle filter; e.g. EP2650042B1).
  • cGPF catalyzed gasoline particle filter
  • the quality of a catalytically coated exhaust gas filter is measured using the criteria of filtration efficiency, catalytic performance and pressure loss.
  • filters are used Provide with catalytically active zones. As mentioned, the zones can be present on the walls of the cells or in the porous wall of the filter matrix.
  • Both process groups have in common that the coating suspension is introduced into the filter by applying a pressure difference, that is to say through the presence of different pressures on the two end faces of the filter.
  • the coating suspension moves in the channels of the filter in the direction of the lower pressure.
  • the first group also works with an excess of coating suspension, which is brought into the filter substrate by a pressure difference and the excess coating suspension is removed from the channels again by a subsequent pressure difference reversal.
  • an excess of coating suspension means that the amount of suspension used for the coating process is clearly above the value required for the desired loading of the filter with catalytically active material.
  • the excess coating suspension is to be removed from the filter again by appropriate measures, for example a reversal of the pressure difference.
  • a pressure difference reversal is understood in the context of the invention that a pressure difference applied to the respective ends of the wall flow filter is reversed, thus changing its sign. This reversal of the pressure difference therefore works against the original coating direction.
  • the second group works without a pressure difference reversal and a washcoat excess, i.e. the total amount of suspension intended and presented for the coating remains essentially, i.e. > 97% of the solids content of the coating suspension, in the substrate.
  • the first group includes W006021338A1, which describes a method for coating a wall flow particle filter with a coating composition, the wall flow filter being made from an open-pore material, having a cylindrical shape with the length L and having a large number from an entry end face to an exit end face of flow channels, which are mutually closed.
  • W009103699A1 describes a process for coating filters with two different washcoats, the process steps being that the filter substrate is aligned vertically, a first coating suspension is pumped in from below (pressure difference with the highest pressure at the lower end), which is excess coating suspension is removed by suction (pressure difference reversal) and the filter body is again filled with the second washcoat from below after rotating through 180 ° and the excess is removed by suction. The filter is dried and calcined after the coating process.
  • the same coating principle is disclosed in US7094728B2.
  • EP1716903B1 proposes a method for coating filter bodies in which the filter, after coating, is freed from too much coating dispersion by immersion in a washcoat suspension by repeatedly applying pressure pulses to one end of the filter body in such a way that excess coating suspension is removed from the filter body Filter body is pushed until it has reached its optimal coating weight. Aim seems among others Again, the reduction in the exhaust back pressure of the filter. This is obviously an in-wall coating
  • the second group of coating processes in which the filter bodies are coated without excess washcoat and without pressure difference reversal, include, for example, the processes described in W006021339A1, W015145122A2 and W001 10573A2.
  • the coating of the vertically aligned filter carrier with the washcoat can be carried out from the lower or the upper end face.
  • W006021339A1 discloses a method for coating a wall flow particle filter with a coating composition, wherein the particle filter is made of an open-pore material, has a cylindrical shape with the length L and has a plurality of flow channels from an inlet end surface to an outlet end surface are mutually closed.
  • the method is characterized in that the flow channels of the wall flow filter are aligned vertically, so that one end face is at the bottom and the second end face is at the top, the filter by immersing the lower end face of the wall flow filter in a definite Niert, submitted amount of the coating composition and applying a vacuum to the openings of the outlet channels in the upper end face and sucking the entire amount of the coating composition into the inlet and outlet channels through the openings of the inlet channels in the lower end face is filled.
  • the amount of the coating composition presented is selected according to the desired coating concentration and coating height. There is no pressure difference after coating after applying the pressure difference for coating. The coating suspension is measured and not used in excess.
  • W ⁇ 01 10573A2 also describes a method for coating particle filters, in which a measured amount of washcoat is applied to the filter carrier from below.
  • a pressure difference vacuum on the upwardly directed end face
  • the amount of coating suspension is sucked into the channels of the substrate.
  • the substrate is then rotated and the washcoat is distributed in the channels by the action of an air jet of pressurized air on the upper end of the substrate.
  • the W ⁇ 15145122A2 is a further example for this group of coating processes.
  • a predefined amount of coating suspension is applied to the upper end face of the vertically aligned filter and by applying a pressure difference (suction by applying a Vacuum to the lower end face) distributed in the channels of the particle filter. After this coating step, there is no further reversal of pressure difference.
  • the object of the present invention is to specify a manufacturing process for catalytically coated, ceramic wall-flow filter substrates, which particularly allows to generate improved wall flow filter substrates compared to the prior art.
  • the wall-flow filters produced in this way should be superior to the substrates produced according to the prior art, especially with regard to the requirement of the lowest possible exhaust gas back pressure while still having sufficient catalytic activity and filtration efficiency.
  • Another object of the present invention was to specify filter substrates produced by the above process and their use in exhaust gas aftertreatment.
  • the wall flow filter having a first end face, a second end face and a length L and a porosity of at least 50% to a maximum of 80% and an average pore diameter from 5 to 50 pm, so that the method comprises the following steps: i) a first coating suspension is introduced in excess over the first end face by applying a pressure difference across the wall flow filter; ii) With a pressure difference reversal, an excess of the first coating suspension is removed from the wall flow filter; iii) a second coating suspension without excess is brought into the second end face by applying a pressure difference across the wall flow filter, this is extremely surprising, but no less advantageous for solving the task.
  • the present invention is based on the combination of two coating methods, with which a known wall flow filter is acted upon with catalytically active materials, and is therefore coated.
  • Steps i) and ii) are in a way part of a first coating process and step iii) depicts the second coating process.
  • the sequence of the individual process steps in a first approximation is not decisive.
  • step iii) can also be carried out before step i). It is only important that step ii) always takes place after step i), although these steps do not have to be carried out directly one after the other.
  • step iii) between steps i) and ii) are carried out.
  • other intermediate steps not mentioned here, e.g.
  • intermediate drying or calcination or rotation of the substrate can be carried out within the scope of the invention, provided that the inventive success is not unduly impaired here. It should also be mentioned that the coating can be carried out with the same or different catalytically active materials, with and without intermediate drying.
  • a first coating suspension is introduced in excess over the first end face by applying a pressure difference across the wall flow filter and then an excess of the first coating suspension is removed from the Wall flow filter removed.
  • the pressure difference reversal removes said excess coating suspension against the coating direction from the channels of the wall flow filter.
  • a second coating suspension is then introduced into the wall flow filter without excess via the second end face by applying a pressure difference.
  • drying takes place after the introduction of the second coating suspension.
  • a first coating suspension is introduced from the first end face without excess in the vertically locked wall flow filter by applying a pressure difference between the end faces of the wall flow filter. Then you bring a second coating suspension a second end face with an excess by applying a pressure difference between the end faces of the wall flow filter. Only then is an excess of the second coating suspension removed by reversing the pressure difference against the coating direction from the wall flow filter in a step which does not necessarily follow directly.
  • a drying step is carried out, optionally also after the introduction of the first coating suspension and before the introduction of the second coating suspension.
  • step ii) can be carried out directly after step i) or only after step iii).
  • step ii With the pressure difference reversal, which occurs to remove the excess coating suspension by step i) (step ii), the second coating suspension is simultaneously introduced into the wall flow filter. This leads to a much more compact process that can be implemented well and robustly in production.
  • a suspension which has catalytically active materials is introduced into the filter, for example via the lower end face of the wall flow filter.
  • the pressure difference used for filling is preferably between 0.05 bar and 4 bar, more preferably between 0, 1 and 3 bar and particularly preferably between 0.5 and 2.5 bar. This pressure difference is selected depending on the viscosity of the suspension and the cell dimensions of the wall flow filter so that the filling speed in the cells is between 10 mm / s up to 250 mm / s, preferably between 20 mm / s and 200 mm / s and is very preferably between 30 mm / s and 180 mm / s.
  • a coating is formed which is less than the maximum length of the wall flow filter.
  • the zone length can be> 15%, more preferably 20% - 85%, very preferably 25% - 75% and extremely preferably 30% - 70% of the length L of the wall flow filter.
  • this coating can also extend to at least 1.25 cm from the lower end face.
  • Excess coating suspension is preferably subsequently removed in step ii) by applying a pressure pulse with reversal of pressure difference from the channels of the wall flow filter against the coating direction downwards.
  • the pressure pulse described in the pressure difference reversal is accordingly, according to the invention, in particular a measure which is sufficient to catalytically catalyze the larger channels or pores (eg Q3 distribution> d50 of the pore diameter) through the wall of the pores present above or in these pores to free active material as much as possible.
  • a corresponding pressure pulse according to the invention is set against the coating direction (pressure difference reverse), which ensures that that the large pores are blocked as little as possible by the coating components of the catalytically active material.
  • the exhaust gas flow can later flow through the wall of the ceramic filter without a significantly higher exhaust gas back pressure.
  • the catalytically active material can still be present on the smaller pores, which make up the majority of the total porosity of the filter material, without excessively impeding the exhaust gas flowing through.
  • the substrates produced in this way, in combination with catalytically active coating zones, show good catalytic activity with sufficient filtration efficiency and a reduced exhaust gas back pressure compared to the catalytically active filters of the prior art.
  • the pressure impulse against the coating direction (reversal of pressure difference) only "blows” or “vacuums” the large, continuous pores or channels that reach through the wall.
  • the catalytically active substance predominantly remains on or in the smaller pores of the filter walls.
  • the maximum pressure difference should be reached within ⁇ 0.5 s, more preferably ⁇ 0.2 s and most preferably ⁇ 0.1 s.
  • the pressure pulse when the pressure difference is reversed should not exceed 400 mbar, more preferably 370 mbar and very preferably 350 mbar, since otherwise too much of the excess coating suspension is removed.
  • a lower limit is generally the fact that the large pores are opened at all.
  • the lower limit will therefore preferably be at least 100 mbar, more preferably at least 120 mbar and very preferably at least 150 mbar.
  • the quantities for the pressure pulse represent a pressure difference that is applied via the wall flow filter from a first end face to a second end face. The person skilled in the art knows how to do this by apparatus. By blowing / sucking especially the large pores, an optimal balance between exhaust gas back pressure, filtration efficiency and catalytic activity of the wall flow filter is achieved.
  • the holding time can be adjusted depending on the properties of the wall flow filter (porosity, wettability, water absorption capacity, etc.).
  • the holding time is preferably between 0s and 10s, more preferably between 0s and 5s and particularly preferably between 0 and 2s.
  • the method according to the invention can be used both for the production of cost and in-wall coatings.
  • the solid constituents of the suspension contain less than 20% by weight, more preferably less than 15% by weight and very preferably less than 10% by weight, based on the amount of solid constituents, in the wall of the Filters can penetrate.
  • the suspension is to a large extent in the pores of the wall of a wall-flow filter of> 80% by weight, more preferably> 90% by weight and very preferably> 95% by weight.
  • the different behavior of the respective coating suspension is controlled very decisively via the particle size distribution of the solid particles in the suspension.
  • Expensive coatings are preferably achieved in that the catalytically active material contains high-surface area metal compounds, in particular oxides, whose mean particle diameter (DIN 66160 - latest version on the filing date) d50 of the Q3 distribution in relation to the mean pore diameter of the filter d50 of the Q3 method.
  • division is preferably> 1: 6 and ⁇ 1: 1 and particularly preferably> 1: 3 and ⁇ 1: 2 (https://de.wikipedia.org/wiki/P
  • An upper limit is generally the value which can be assessed as meaningful by the person skilled in the art with the appropriate cost coatings.
  • the particle diameter d99 of the Q3 distribution in the suspension in relation to the average pore diameter of the pores in the filter walls should be preferably ⁇ 0.6: 1, more preferably ⁇ 0.5: 1 and particularly preferably ⁇ 0.4: 1. This can then be used to manufacture wall flow filters, e.g. are shown in Fig. 5.
  • the catalytic coating of the wall flow filter produced according to steps i) and ii) has a positive gradient for the amount of catalytically active material in the coating direction. This means that after step ii) there are fewer catalytically active materials in the vicinity of the end face via which the coating suspension was introduced into the wall flow filter than further in the middle of the wall flow filter in Viewed in the longitudinal direction (Fig. 3, 10a).
  • an expense zone generated in accordance with the invention has a quantitative distribution of catalytic material, measured in material / length unit, so that after removal of the stopper over a range of, for example, 15 to 40 mm from the coating inlet end, 20% by weight to 70% by weight .-% less than is contained in a subsequent coated area of the zone.
  • the amount of active components in the coating direction over a length of, for example, 80 mm of the substrate has a positive concentration gradient in the range from 20% to 100%, more preferably 25% to 90%.
  • the concentration gradient due to the different quantity and distribution of the catalytically active materials can be determined, for example, gravimetrically, by evaluating X-ray absorption data (XRF measurement) or by measuring the BET surface area of certain filter sections along the longitudinal axis of the filter.
  • XRF measurement X-ray absorption data
  • a method is carried out as previously described (steps i) and ii)).
  • a certain amount of a suspension containing a catalytically active material (identical or different from the first) is additionally applied to the upper end face during or afterwards - with or without intermediate drying - and this is applied by applying a pressure increase the upper end face and / or pressure reduction on the lower end face (pressure difference) of the wall flow filter in the vertically locked wall flow filter, so that this coating extends to less than 100% of the length of the wall flow filter (step iii)).
  • the length of this zone coating in the channels adjacent to the first coating can be determined by a person skilled in the art. It is at least 20% and a maximum of 95% of the length L of the wall flow filter. Preferably 40% to 85%, particularly preferably 50% to 70%. A possible embodiment is shown in FIG. 4.
  • step i) it is filled from below with a pressure difference with washcoat in excess to a certain coating length, excess washcoat by a pressure difference reversed removed (step ii), rotates the filter 180 ° and then immerses the lower end face in a predefined amount of coating suspension and this is filled with the pressure in the second end channels with a pressure difference while applying a vacuum to the upper end face (step iii) .
  • particle filters with catalytically active zones in the inlet and outlet channels can be produced as shown in FIGS. 2 and 3.
  • the two zones (10a, 10b) do not have to overlap.
  • the coatings preferably overlap at least 5%, more preferably up to 20% and very preferably for 7% -15% of the length L of the wall-flow filter.
  • the filtration efficiency of the filter as a whole and in particular of the free area can then be specifically adapted to the requirements of the wall-flow filter after drying by means of a subsequent powder coating.
  • the powder coating for increasing the filtration efficiency is known to the person skilled in the filter technology under the term precoat (for example US4010013).
  • the process steps i) - iii) according to the invention can be combined in such a way that in the case of the vertically oriented wall flow filter substrate, the suspension is brought in from the upper end face and the coating is treated after step i). happens with the at least one pressure pulse at the same time.
  • the suspension applied to the upper end face of the wall flow filter is simultaneously sucked or pressed into the wall flow filter. So you proceed step by step so that first the suspension is inserted into the wall flow filter from below, then the suspension is applied to the upper face and then both suspensions are treated with the at least one pressure pulse.
  • This leads to a particularly preferred method since two identical or different coatings from different ends of the wall-flow filter can be introduced into the latter in a few work steps. As a result, e.g. Filter architectures of Fig. 4 can be obtained.
  • the suspensions applied from below or from above can be very general or different. It is optionally possible to dimension both the coating applied as the first and the coating applied as the second as an expense coating or as an in-wall coating.
  • the present invention also relates to a catalytically coated ceramic wall-flow filter produced according to the invention for the treatment of exhaust gases from a combustion process. Further advantageous embodiments for the method just described also apply to the wall flow filter specified here, insofar as they have an influence on the spatial-physical design of the filter.
  • a very preferred wall flow filter has - as described - viewed from both sides a catalytically active coating in the channels, of which at least one coating represents a porous application coating with a gradient of the washcoat concentration from the front (e.g. Fig. 4/5 ).
  • the filter has no preferred direction.
  • it is preferably installed in the exhaust system of a vehicle with a stoichiometrically operated internal combustion engine in such a way that the coating, which was produced by coating with excess suspension and pressure differential reversal (steps i) and ii)), is located in the outlet duct, as seen in the flow direction (FIG . 1).
  • the catalytically active coatings of the filter can be selected from the group consisting of three-way catalyst, SCR catalyst, nitrogen oxide storage catalyst, oxidation catalyst, soot ignition coating, hydrocarbon storage.
  • the catalytically active coatings used can be in the pores and / or on the surfaces of the channel walls of the filter.
  • the present invention also relates to the use of the filter according to the invention in a process for the oxidation of hydrocarbons and / or carbon monoxide and / or in a process for nitrogen oxide reduction, which originate from a combustion process, preferably that of a car engine.
  • the filter according to the invention is particularly preferred in exhaust systems of an internal combustion engine as SDPF (SCR catalyst coated on a wall flow filter), cGPF (3-way catalyst coated on a wall flow filter), NDPF (NOx storage catalyst coated on a wall flow filter) or cDPF (diesel oxidation catalyst coated on a wall flow filter) is used.
  • a preferred application is the removal of nitrogen oxides from lean exhaust gases using the SCR process.
  • SCR treatment of the preferably ma gere exhaust gas is injected into this ammonia or an ammonia precursor compound and both passed through an SCR catalytically coated wall flow filter according to the invention.
  • the temperature above the SCR filter should be between 150 ° C and 500 ° C, preferably between 200 ° C and 400 ° C or between 180 ° C and 380 ° C, so that the reduction can take place as completely as possible.
  • a temperature range from 225 ° C. to 350 ° C. is particularly preferred for the reduction.
  • N0 2 / NOx ratio of around 0.5. This applies not only to SCR catalysts based on metal-exchanged zeolites, but also to all common, ie commercially available, SCR catalysts (so-called Fast SCR). A corresponding NO: N0 2 content can be achieved by means of oxidation catalysts which are positioned upstream of the SC R catalyst.
  • the injection devices used can be chosen arbitrarily by a person skilled in the art. Suitable systems can be found in the literature (T. Mayer, solid SCR system based on ammonium carbamate, dissertation, TU Kaiserslautern, 2005).
  • the ammonia can be introduced via the injection device as such or in the form of a compound into the exhaust gas stream, which causes ammonia to form under the ambient conditions.
  • aqueous solutions of urea or ammonium formate come into question, as does solid ammonium carbamate.
  • the person skilled in the art particularly preferably uses injection nozzles (EP031 1758A1). This is used to set the optimum NHb / NOc ratio so that the nitrogen oxides can be converted to N as completely as possible.
  • Wall flow filters with an SCR catalytic function are called SDPF. These catalysts often have a function for storing ammonia and a function in that nitrogen oxides can react together with ammonia to form harmless nitrogen.
  • An NH-storing SCR catalytic converter can be designed according to the types known to those skilled in the art. In the present case, this is a wall flow filter coated with a material that is catalytically active for the SCR reaction, in which the catalytically active material — commonly called the “wash coat” - is present in the pores of the wall flow filter.
  • the component which is catalytically active in the actual sense can also contain other materials such as binders made from transition metal oxides and high-surface carrier oxides such as titanium oxide, aluminum oxide, in particular gamma-AhOs, zirconium oxide or cerium oxide.
  • binders made from transition metal oxides and high-surface carrier oxides such as titanium oxide, aluminum oxide, in particular gamma-AhOs, zirconium oxide or cerium oxide.
  • SCR catalysts are those which are composed of one of the materials listed below.
  • zoned or multi-layer arrangements or arrangements of several components in succession (preferably two or three components) with the same or different materials can also be used as the SCR component. Mixtures of different materials on a substrate are also conceivable.
  • the actual catalytically active material used according to the invention in this regard is preferably selected from the group of transition metal-exchanged zeolites or zeolite-like materials (zeotypes). Such connections are well known to the person skilled in the art.
  • materials from the group consisting of levynite, AEI, KFI, chabazite, SAPO-34, ALPO-34, zeolite ⁇ and ZSM-5 are preferred.
  • Zeolites or zeolite-like materials of the chabazite type, in particular CHA or SAPO-34, and LEV or AEI are particularly preferably used.
  • these materials are preferably provided with transition metals from the group consisting of iron, copper, manganese and silver.
  • the metal to framework aluminum or in the SAPO-34 framework silicon ratio is usually between 0.3 and 0.6, preferably 0.4 to 0.5.
  • the specialist knows how he has to provide the zeolites or the zeolite-like material with the transition metals (EP0324082A1, W0130927071 1A1, WO2012175409A1 and the literature cited therein) in order to be able to provide good activity against the reduction of nitrogen oxides with ammonia.
  • Vanadium compounds, cerium oxides, cerium / zirconium mixed oxides, titanium dioxide and tungsten-containing compounds and mixtures thereof can also be used as catalytically active material.
  • Such compounds can be selected from the group consisting of zeolites, such as, for example, mordenite (MOR), Y-zeolite (FAU), ZSM-5 (MFI), ferrierite (FER), chabazite (CHA) and other small pore zeolites “Like LEV, AEI or KFI, and ß-zeolites (BEA) as well as zeolite-like materials such as aluminum phosphates (AIPO) and silicon aluminum phosphate SAPO or mixtures thereof can be used (EP0324082A1).
  • ZSM-5 (MFI), chabazite (CHA), ferrierite (FER), ALPO or SAPO-34 and ⁇ -zeolites (BEA) are particularly preferably used.
  • CHA, BEA and AIPO-34 or SAPO-34 are very particularly preferably used.
  • Materials of the LEV or CHA type are used with extreme preference and here CHA or LEV or AEI are most preferably used. If one already uses a zeolite or a zeolite-like compound as the catalytically active material in the SCR catalytic converter, the addition of further IMH3-storing material can of course advantageously be omitted.
  • the ammonia storage capacity can be determined using a synthesis gas system.
  • the catalyst is first conditioned at 600 ° C with synthesis gas containing NO in order to completely remove ammonia residues in the drill core. After cooling the gas to 200 ° C is then, at a space velocity of z. B.
  • the synthesis gas is typically composed of 450 ppm NH3, 5% oxygen, 5% water and nitrogen.
  • the wall flow filter according to the invention can also comprise a zone positioned downstream on the downstream side with an ammonia oxidation catalyst (s), which are also referred to as ammonia slip catalysts (“ASC”), in order to oxidize excess ammonia and to adhere to it prevent it from being released into the atmosphere.
  • ASC ammonia slip catalysts
  • the ASC may be mixed with an SCR catalyst.
  • the ammonia oxidation catalyst material may be selected to promote the oxidation of ammonia instead of NOx or N2O formation.
  • Preferred catalyst materials include platinum, palladium, or a combination thereof.
  • the ammonia oxidation catalyst can include platinum and / or palladium supported on a metal oxide.
  • the catalyst is arranged on a high surface area support, including but not limited to alumina.
  • the ammonia oxidation catalyst comprises a platinum group metal on a silicon-containing support.
  • a silicon-containing material may include a material such as: (1) silica, (2) a zeolite with a silica-to-alumina ratio of at least 200, and (3) amorphous silica-doped alumina with an SiO 2 content > 40%.
  • a platinum group metal is present on the support in an amount from about 0.1% to about 10% by weight of the total weight of the platinum group metal and the support.
  • Preferred materials for ASCs can be found, for example, in WO2018183457A1, WO2018141887A1, WO2018081247A1.
  • the use of the wall flow filter according to the invention is very particularly preferred in a process for the simultaneous oxidation of hydrocarbons and carbon monoxide and in a process for nitrogen oxide reduction.
  • This method is preferably the one that takes place in a three-way catalytic converter in the stoichiometric exhaust gas. It is preferred if, in addition to this wall flow filter, there is also a three-way catalytic converter on the downstream side or on the upstream side of the exhaust gas system. Possibly. there are also 2 separate three-way catalysts, particularly preferably one on the upstream side and one on the downstream side of the wall-flow filter according to the invention in the exhaust system.
  • the wall flow filter is very particularly preferably used as a cGPF with a three-way function.
  • the coatings considered here mostly contain platinum group metals, such as Pt, Pd and Rh, as catalytically active components, with Pd and Rh being particularly preferred.
  • the catalytically active metals are often highly dispersed on combatoberflä-containing oxides of aluminum, cerium, zirconium and titanium or mixtures or mixed oxides thereof, which by further transition elements such. B.
  • Such three-way catalysts also contain oxygen storage materials (e.g. Ce / Zr mixed oxides; see below).
  • oxygen storage materials e.g. Ce / Zr mixed oxides; see below.
  • a suitable three-way catalytic coating is described for example in EP1181970B1, EP1541220B1, W020081 13445A1, W02008000449A2, to which reference is hereby made with regard to the use of catalytically active powder.
  • Diesel engines without DPF can have up to ten times higher particle emissions, based on the particle mass, than petrol engines without GPF (Maricq et al., SAE 1999-01-01530).
  • Emissions in gasoline engines range from particle sizes smaller than 200 nm (Hall et al., SAE 1999-01-3530) to 400 nm (Mathis et al., Atmospheric Environment 38 4347) with the maximum in the range of around 60 nm to 80 nm.
  • the three-way catalysts just mentioned can be equipped with a nitrogen oxide storage functionality in powder (TWNSC).
  • TWNSC nitrogen oxide storage functionality in powder
  • These catalytic converters consist of materials that give the catalytic converter the function of a three-way catalytic converter under stoichiometric exhaust gas conditions and that have a function for storing nitrogen oxides under lean exhaust gas conditions. These stored nitrogen oxides are regenerated during short, rich operating phases in order to restore their storage capacity.
  • a corresponding TWNSC is preferably produced by combining materials which are used for the construction of a three-way catalytic converter and a nitrogen oxide storage catalytic converter.
  • a particularly preferred embodiment for such a catalyst is described for example in WO2010097146A1 or WO2015143191A1.
  • An air / fuel mixture which corresponds to an l of 0.8 to 1 is preferably maintained during the regeneration. This value is particularly preferably between 0.85 and 0.99, very particularly preferably between 0.95 and 0.99.
  • Porous wall flow filter substrates made of cordierite, silicon carbide or aluminum titanate are preferably used. These wall-mounted flow filter substrates have inflow and outflow channels, the outflow-side ends of the inflow channels and the upstream-side ends of the outflow channels being closed off from one another with gas-tight “plugs”.
  • the exhaust gas to be cleaned which flows through the filter substrate, is forced to pass through the porous wall between the inflow and outflow channels, which requires an excellent particle filter effect.
  • the filters can be symmetrical or asymmetrical.
  • the inflow channels are either the same size as the outflow channels or the inflow channels are enlarged compared to the outflow channels, i.e. they have a larger so-called "open frontal area” (OFA) compared to the outflow channels.
  • OFA open frontal area
  • the open porosity of the uncoated wall flow filter is usually more than 50% to a maximum of 80%, generally from 50% to 75%, especially from 50% to 70% [measured according to DIN 66133 - latest version on the filing date].
  • the average pore diameter d50 of the uncoated filter be at least 5 pm, z. B.
  • the finished filters with an average pore diameter (d50) of generally 10 pm to 25 pm and a porosity of 50% to 65% are particularly preferred.
  • Each of the known manufacturing methods for applying the catalytic coating described above as prior art has advantages and disadvantages in so-called in-wall coatings or expense coatings in the filter, generally depending on which zone is located on the inlet or outlet side of the filter in the exhaust air stream.
  • the zone in the wall of the filter regardless of which group of processes is produced, has in principle poor filtration properties and poor performance, but a very low pressure drop.
  • the process with reversal of the pressure difference and with an excess of coating suspension during coating (group 1) has an average catalytic performance, an average filtration efficiency and an average pressure loss in the case of application zones.
  • the process without reversing the pressure difference and without excess coating suspension during coating (group 2) has good catalytic performance and filtration efficiency in the case of application zones, but has a very high pressure loss.
  • the wall-flow filter according to the invention considered here has acquired its decisive character through the manner of the coating.
  • the starting point is a catalytic coating applied in a special form to the filter, which is made porous by the application of a pressure pulse against the coating direction (reversal of pressure difference) and therefore has a desired high permeability.
  • This coating is combined with a coating in the adjacent ducts that is designed as an in-wall or an expense, which has not been exposed to a reversal of the pressure difference.
  • This filter produced by combining the two coating variants, has surprising advantages over coated wall-flow filters, which were only manufactured according to one of the coating principles shown.
  • optimized particle filters can be produced with such configurations according to the invention, which can be tailored precisely to the respective application or the particular exhaust gas problem. Against the background of the known prior art, this was not to be expected. Characters:
  • Fig. 1 shows an example of the effect of various combinations of various coating architectures using patterns 1 (top) - 4 (bottom). With regard to their effect in the exhaust gas flow.
  • the combination of two coatings with a high permeability has the lowest pressure loss, but is otherwise weaker than the other samples according to the invention in terms of filtration efficiency, light-off temperature and OSC (oxygen storage).
  • the combination of two coatings with low permeability shows very good values in terms of light-off temperature, OSC and filtration efficiency, but does result in an enormous increase in pressure.
  • the best combination of all features is shown by the combination of a coating with low permeability in the entry line (inlet side of the filter in the exhaust gas; E) with a porous coating according to the invention with a high permeability in the Output line (outlet side of the filter in the exhaust gas; A).
  • the optimal setting of the two zone lengths depends on the requirements of the respective motor. With this you can set the quality criteria of the coated filter like with a slider over the zone length.
  • Fig. 2 shows schematically the product with two expense zones, which result from the combination of the coating process.
  • a porous coating 400 also called filter cake
  • the exhaust gas 600 flows over the coating 500 and flows through the porous matrix of the filter 100 and the open-porous coating 400.
  • the layer 400 is also flowed over after the flow.
  • Fig. 3 relates to the combination of a device manufactured in accordance with the invention (10a) and an additional in-wall coating (10b) coming from the other side.
  • the preferred embodiment is shown with an overlap.
  • FIG. 4 The figures show four exemplary embodiments of samples 1 to 4 from the experimental part
  • Fig. 5 shows the coating concentration along the longitudinal direction of two manufactured according to the invention (samples 2 and 3) and two not according to the invention Wall flow filters (patterns 1 and 4). All three variants have the same total coating quantity for loading. The five panes per variant were shown (standardized) relative to the loading of the first pane on the left. The distribution of the oxide load over the length of the filter measured by determining the BET surface area is shown by way of example for different combinations of coatings for two zones on the wall.
  • Fig. 6 shows the permeability distribution of two effort zones produced according to the invention
  • Alumina stabilized with lanthanum oxide was placed in water together with a first oxygen storage component, which comprised 40% by weight cerium oxide, zirconium oxide, lanthanum oxide and prase odymoxide, and a second oxygen storage component, which comprised 24% by weight ceria, zirconium oxide, lanthanum oxide and yttrium oxide suspended. Both oxygen storage components were used in equal parts.
  • the suspension he was then kept with constant stirring with a palladium nitrate solution and a rhodium nitrate solution.
  • the resulting coating suspension (washcoat) was used directly to coat a commercially available wall-flow filter substrate.
  • the methods for producing products are described below, each of which has two application zones, which have been coated from different end faces of the filter and each extend over approximately 60% of the length of the filter.
  • the ratio of ceramic oxides to precious metals is the same in the washcoat of both zones and constant across the filter.
  • the total amount of oxide and precious metal is divided equally between the two zones during the coating process, which ideally means that an oxide amount of 83.55 g and a precious metal amount of 1.07 g are applied in each zone coating step.
  • Both washcoat zones a) and b) of sample 1 were produced using the same coating method, the ceramic suspension being first brought into the filter by applying a pressure difference (pressure from below). The excess of oxides is then reversed by a pressure difference, i.e. the renewed application of a pressure difference (suction from below), which is opposite to the first, is removed.
  • zone a is coated from below from front face A.
  • the suspension has a solids content of around 33% and is pressed into the substrate until 60% of the substrate length is filled with washcoat from bottom to top.
  • the excess washcoat is then removed from the filter with a short suction pulse in the opposite direction to the coating (approx. 330 mbar suppression, 1.5 sec.).
  • the filter is coated from the front side B from below to produce zone b).
  • the coating is carried out analogously to the coating of zone a), only the coating parameters differ slightly (solids concentration around 35%, suction pulse vacuum around 210 mbar, suction pulse duration around 0.5 sec., The suction pulse rose within 0.2 sec the maximum).
  • the filter is then dried and calcined. Pattern 2 and Pattern 3 (according to the invention)
  • Pattern 2 (FIG. 4b) and pattern 3 (FIG. 4c) were produced according to a procedure where the coating of zone a) and zone b) each have a different coating process.
  • zone a) is coated from below from front face A.
  • the suspension has a solids content of around 34% and is pressed into the substrate until 60% of the substrate length is filled with washcoat from bottom to top.
  • the excess washcoat is then removed from the filter with a short suction pulse (around 330 mbar suppression, 1.5 sec. Suction pulse duration, increase of the suction pulse within 0.2 sec to the maximum).
  • the filter is coated from the front side B from above to produce zone b).
  • a measured amount of washcoat (solids content approx. 44%) is added to face B from above and a short suction pulse (250 mbar suppression, 3 sec.) Is applied to distribute the washcoat in the filter.
  • the filter is then dried and calcined.
  • Both washcoat zones a) and b) of sample 4 were produced using the same coating method, with the ceramic suspension being applied to the wall-flow filter from above and brought into the filter by applying a pressure difference (suction from below) was (not according to the invention).
  • zone a) is coated from above from front face A.
  • the suspension has a solids content of around 43-45% and is added in a measured amount from the top to face A.
  • a pressure difference in the form of a short suction pulse 250 mbar suppression, 1 sec. Is applied to distribute the washcoat in the filter.
  • the filter is coated from the front side B from above to produce zone b).
  • the coating parameters for this are analogous to those for zone a).
  • the filter is then dried and calcined. Characterization:
  • the effectiveness of a catalytically active filter is determined by the interplay of the functional parameters of catalytic performance, filtration efficiency and exhaust gas back pressure (back pressure), which essentially result from the distribution of the catalytic material and the permeability of the washcoat layers.
  • the distribution and amount of the catalytically active material in the direction of flow through the filter is determined by measuring the BET surface area (DIN 66132 - latest version on the filing date) and the permeability by measuring the back pressure on filter samples of samples 1 to 4.
  • a block with 10mmx10mmx20mm was sawn out of each disc in the middle. Every second channel was mutually blocked, so that a small mini filter was created.
  • the pressure loss is measured at an air flow of 6 l / min. In a first approximation, the pressure loss is set to be proportional to the permeability.
  • the suspensions used had identical particle size distributions and identical Pd to oxide ratios. Due to the different processes, the suspensions had different viscosities and different solids concentrations. The gradient was always standardized with the value of the disc on the left.
  • All 3 variants (pattern 1, pattern 2/3, pattern 4) have the same amount of washcoat as a load.
  • Fig. 6 shows the course of the permeability by way of example for the combination of two wall zones, the zone on the left having a washcoat excess and a reversal of the pressure difference during the coating being produced during process steps i) to ii) of the first preferred embodiment of the process, while the right zone without excess washcoat and without reversing the pressure difference he was created. Both zones contain the same amount of oxides and both cover 60% of the length of the filter.
  • the plugs of the filter were first removed. The rest was divided into 5 equally long discs with a length of approx. 26mm. Small blocks with a base area of 10mm x 10mm and a height of 26mm were made from the panes. The channels were provided with plugs so that 5 small filter bodies were created. A pressure difference volume flow curve was now determined for the small filters and the permeability was calculated using the Darcy equation. The left zone was used to standardize the permeability of the five small filters.
  • the first pane of the zone hereinafter referred to as area A, which was produced with a washcoat excess and a reversal of the pressure difference during the coating, has a 4 to 20 times higher permeability in the first 15 to 50 mm than has the zone in the following mm.
  • the length L was measured from the end face after removal of the plugs, which had the first contact with the washcoat when coated with excess washcoat and a reversal of the pressure difference.
  • the zone that was created without excess washcoat and without reversing the pressure difference during coating has a permeability with the same grain size distribution of the oxides in the washcoat, the same amount of oxide in the zone, which corresponds to only 5% to 25% of the permeability of area A. The same applies to the area of the zone which was generated with a washcoat excess and a reversal of the pressure difference during the coating, which is further away from the end face than area A.
  • Tab. 1 shows the distribution of the oxides and the resulting permeability in a zone that was generated from below according to process steps i) to iii) (the length measurement starts behind the stopper). The range 0-26mm was used for standardization to 100% Tab. 1
  • Tab. 2 shows the different permeabilities of the coatings from above and below (the length measurement starts behind the stopper). The area 0-26 mm of the coating from below was set to 100% for standardization. Tab. 2
  • the particle filters samples 1 to 4 were subjected to an engine test bench aging. This consists of a fuel cut-off switch with 950 ° C exhaust gas temperature in front of the catalyst inlet (maximum bed temperature 1030 ° C). The aging time was 19 hours (see Motortechnische Zeitschrift, 1994, 55, 214-218).
  • the particle filter pattern 2 shows a slight improvement in the light-off behavior compared to pattern 1 in the aged state.
  • Particle filters Samples 3 and 4 show a marked improvement in light-off behavior and a slight improvement in dynamic CO / NOx conversion compared to Sample 1 in the aged state.
  • Samples 3 and 4 show a significantly increased ability to store oxygen after aging compared to sample 1.
  • the particle filter samples 1 to 4 were compared on a cold blow test bench with regard to the exhaust gas back pressure.
  • Table 6 contains pressure loss data which were determined at an air temperature of 21 ° C and a volume flow of 300 m 3 / h. Tab. 6
  • the two patterns in which the coating processes for zone a) and zone b) differ have an acceptable increase in pressure loss with respect to sample 1, but have a significantly lower pressure loss compared to sample 4.
  • the particle filters described were examined on the engine test bench in the real exhaust gas of an engine operated with an average stoichiometric air / fuel mixture with regard to the fresh filtration efficiency.
  • WLTP Worldwide harmonized Light vehicles Test Procedure
  • the driving cycle used was WLTC Class 3.
  • the particulate filter was installed 30 cm after a conventional three-way catalytic converter, which was the same for all measured particulate filters.
  • About particle emissions To be able to detect during the test, a particle counter was installed in front of the three-way catalytic converter and after the particle filter. Table 7 shows the results of the filtration efficiency measurement.
  • sample 1 The lowest filtration efficiency is shown in sample 1, in which both zones were produced using the same coating method in accordance with steps i) - ii).
  • sample 4 in which both zones were also produced using the same coating method, but different from sample 1, excluding steps i) - ii), has the highest filtration efficiency.
  • 1 shows an example of a summary of the effect of different combinations of different overhead washcoat layers with regard to the effect in the exhaust gas flow.
  • the combination of two layers with a high permeability which were each produced using a coating method according to the invention according to process steps i) to iii) by applying a pressure difference and a subsequent pressure difference reversal (pattern 1), has the lowest pressure loss, but is otherwise the same Filtration efficiency, the light-off temperature and the OSC are weaker than the other samples 2 to 4.
  • the combination of two layers with low permeability which were each produced using a coating method according to the invention by applying a pressure difference (sample 4), shows very good values in terms of light-off temperature, OSC and filtration efficiency, but has led to an enormous increase in pressure Episode.
  • the best combination of all features surprisingly shows the combination of a layer in the input line (upstream side of the filter in the exhaust gas) with low permeability, which was produced according to claim 6 by applying a pressure difference with a Layer in the output line (outflow side of the filter in the exhaust gas) with a high permeability / which was produced via a coating process according to claim 1, process steps i) to iii).
  • the optimal setting of the two zone lengths depends on the requirements of the respective motor. You can set the quality criteria of the coated filter over the zone length like with a slider.

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Abstract

La présente invention concerne un filtre de type "wall-flow", un procédé pour sa fabrication et l'utilisation dudit filtre pour réduire les gaz d'échappement nocifs d'un moteur à combustion interne. Les filtres à particules sont communément utilisés pour filtrer les gaz d'échappement issus d'un processus de combustion. L'invention concerne également de nouveaux substrats filtrants ainsi que leur utilisation spécifique dans le post-traitement des gaz d'échappement
EP20700088.6A 2019-01-04 2020-01-02 Procédé de fabrication de filtres de type "wall-flow" catalytiquement actifs Pending EP3906110A1 (fr)

Applications Claiming Priority (2)

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DE102019100099.8A DE102019100099B4 (de) 2019-01-04 2019-01-04 Verfahren zur Herstellung von katalytisch aktiven Wandflussfiltern, katalytisch aktiver Wandflussfilter und dessen Verwendung
PCT/EP2020/050009 WO2020141190A1 (fr) 2019-01-04 2020-01-02 Procédé de fabrication de filtres de type "wall-flow" catalytiquement actifs

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Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102021107129A1 (de) * 2021-03-23 2022-09-29 Umicore Ag & Co. Kg Partikelfilter für Benzinmotorenabgas
WO2023198571A1 (fr) 2022-04-11 2023-10-19 Umicore Ag & Co. Kg Système de gaz d'échappement pour moteurs à combustion interne à fonctionnement principalement stœchiométrique, comprenant un catalyseur pour réduire les émissions d'ammoniac
DE102023101772A1 (de) 2022-04-11 2023-10-12 Umicore Ag & Co. Kg Abgassystem für überwiegend stöchiometrisch betriebene Verbrennungsmotoren aufweisend einen Katalysator zur Verminderung der Ammoniakemissionen

Family Cites Families (41)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS51117373A (en) 1975-04-08 1976-10-15 Taisei Corp Tar mist contained waste gas purifying device
US4351811A (en) 1977-07-20 1982-09-28 Hitachi, Ltd. Process for reducing an eliminating nitrogen oxides in an exhaust gas
DE3735112A1 (de) 1987-10-16 1989-04-27 Didier Eng Vorrichtung zum dosieren von ammoniak in einen abgasstrom
US4861743A (en) 1987-11-25 1989-08-29 Uop Process for the production of molecular sieves
JPH01151706A (ja) 1987-12-08 1989-06-14 Toyota Central Res & Dev Lab Inc 可燃性微粒子と窒素酸化物を除去するための触媒及びフィルター
US6478874B1 (en) 1999-08-06 2002-11-12 Engelhard Corporation System for catalytic coating of a substrate
DE10020100A1 (de) 2000-04-22 2001-10-31 Dmc2 Degussa Metals Catalysts Verfahren und Katalysator zur Reduktion von Stickoxiden
EP1181970B1 (fr) 2000-08-16 2004-02-04 Umicore AG & Co. KG Catalyseur pour purifier des gaz d'échappement placé près du moteur et son procédé de fabrication
DE10308287B4 (de) 2003-02-26 2006-11-30 Umicore Ag & Co. Kg Verfahren zur Abgasreinigung
US7094728B2 (en) 2003-06-11 2006-08-22 Delphi Technologies, Inc. Method for control of washcoat distribution along channels of a particulate filter substrate
US7229597B2 (en) * 2003-08-05 2007-06-12 Basfd Catalysts Llc Catalyzed SCR filter and emission treatment system
US7875250B2 (en) 2003-12-11 2011-01-25 Umicore Ag & Co. Kg Exhaust treatment device, and methods of making the same
JP4480414B2 (ja) 2004-02-10 2010-06-16 株式会社キャタラー フィルタ触媒の製造方法
US7213395B2 (en) 2004-07-14 2007-05-08 Eaton Corporation Hybrid catalyst system for exhaust emissions reduction
DE102004040551A1 (de) * 2004-08-21 2006-02-23 Umicore Ag & Co. Kg Verfahren zur Beschichtung eines Wandflußfilters mit einer Beschichtungszusammensetzung
DE102004040550A1 (de) 2004-08-21 2006-02-23 Umicore Ag & Co. Kg Verfahren zur Beschichtung eines Wandflußfilters mit einer Beschichtungszusammensetzung
DE102004051099A1 (de) 2004-10-19 2006-04-20 Umicore Ag & Co. Kg Verfahren und Vorrichtung zum Beschichten einer Serie von Tragkörpern
PL2038046T3 (pl) 2006-06-29 2018-09-28 Umicore Ag & Co. Kg Dwuwarstwowy katalizator trójdrożny i jego zastosowanie
EP1974809B1 (fr) 2007-03-19 2010-09-29 Umicore AG & Co. KG Catalyseur trois voies à double couche
DE102008010388B4 (de) 2008-02-21 2015-04-16 Umicore Ag & Co. Kg Verfahren zur Beschichtung eines Dieselpartikelfilters und damit hergestelltes Dieselpartikelfilter
GB0903262D0 (en) * 2009-02-26 2009-04-08 Johnson Matthey Plc Filter
DE102009010711A1 (de) 2009-02-27 2010-09-30 Umicore Ag & Co. Kg Stickoxid-Speicherkatalysator zum Einsatz im Kraftfahrzeug in motornaher Position
DE102009033635B4 (de) 2009-07-17 2020-11-05 Umicore Ag & Co. Kg Katalytisch aktives Partikelfilter mit Schwefelwasserstoff-Sperrfunktion, seine Verwendung und Verfahren zur Entfernung von Stickoxiden und Partikeln
DE102010033689A1 (de) * 2009-08-28 2011-03-03 Umicore Ag & Co. Kg Abgasnachbehandlungssystem mit katalytisch aktivem Wall-Flow-Filter mit NOx-Speicherfunktion vor Katalysator mit gleicher Speicherfunktion
DE102010007499A1 (de) 2010-02-09 2011-08-11 Umicore AG & Co. KG, 63457 Volumetrische Beschichtungsanordnung
GB201100595D0 (en) * 2010-06-02 2011-03-02 Johnson Matthey Plc Filtration improvements
US8323599B2 (en) 2010-11-22 2012-12-04 Umicore Ag & Co. Kg Three-way catalyst having an upstream multi-layer catalyst
US8557204B2 (en) 2010-11-22 2013-10-15 Umicore Ag & Co. Kg Three-way catalyst having an upstream single-layer catalyst
WO2012175409A1 (fr) 2011-06-21 2012-12-27 Umicore Ag & Co. Kg Procédé destiné au dépôt de métaux sur des oxydes de support
US9096923B2 (en) 2011-11-10 2015-08-04 Corning Incorporated Coating apparatus and method for forming a coating layer on monolith substrates
DE102011121971A1 (de) 2011-12-21 2013-07-11 Süd-Chemie AG Verfahren zur Modifikation der Porengröße von Zeolithen
EP2650042B2 (fr) 2012-04-13 2020-09-02 Umicore AG & Co. KG Système de réduction de polluants des véhicules à essence
GB2517238B (en) * 2013-04-24 2020-04-01 Johnson Matthey Plc Filter substrate comprising zone-coated catalyst washcoat
GB2520776A (en) * 2013-12-02 2015-06-03 Johnson Matthey Plc Wall-flow filter comprising catalytic washcoat
US9744529B2 (en) 2014-03-21 2017-08-29 Basf Corporation Integrated LNT-TWC catalyst
GB201405277D0 (en) * 2014-03-25 2014-05-07 Johnson Matthey Plc Method for coating a filter substrate
MX2017016527A (es) * 2015-06-16 2018-05-28 Basf Se Filtro de hollin catalizado (scr) con catalizador de trampa de nox pobre para usar en una reduccion catalitica selectiva pasiva.
GB2556453A (en) 2016-10-26 2018-05-30 Johnson Matthey Plc Hydrocarbon injection through small pore CU-zeolite catalyst
PL3357558T3 (pl) 2017-02-03 2020-03-31 Umicore Ag & Co. Kg Katalizator do oczyszczania gazów spalinowych silników wysokoprężnych
GB2562160B (en) * 2017-03-20 2021-06-23 Johnson Matthey Plc Catalytic wall-flow filter with an ammonia slip catalyst
BR112019020264A2 (pt) 2017-03-29 2020-04-22 Johnson Matthey Plc artigo catalítico, artigo catalisador, sistema de tratamento de emissões, e, método para redução de emissões de uma corrente de escape

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WO2020141190A1 (fr) 2020-07-09
DE102019100099A1 (de) 2020-07-09
CN113226518A (zh) 2021-08-06
US11679359B2 (en) 2023-06-20
US20220080355A1 (en) 2022-03-17
DE102019100099B4 (de) 2022-09-08
CN113226518B (zh) 2024-04-12
US20230311064A1 (en) 2023-10-05

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