WO2008122023A1 - Filtre de réduction catalytique sélective et procédé d'utilisation de ce dernier - Google Patents

Filtre de réduction catalytique sélective et procédé d'utilisation de ce dernier Download PDF

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Publication number
WO2008122023A1
WO2008122023A1 PCT/US2008/059073 US2008059073W WO2008122023A1 WO 2008122023 A1 WO2008122023 A1 WO 2008122023A1 US 2008059073 W US2008059073 W US 2008059073W WO 2008122023 A1 WO2008122023 A1 WO 2008122023A1
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Prior art keywords
scr
nox
filter
catalyst
zone
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PCT/US2008/059073
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English (en)
Inventor
Bilal Zuberi
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Geo2 Technologies, Inc
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Priority claimed from US11/695,585 external-priority patent/US20080236145A1/en
Priority claimed from US11/736,388 external-priority patent/US20080256936A1/en
Application filed by Geo2 Technologies, Inc filed Critical Geo2 Technologies, Inc
Publication of WO2008122023A1 publication Critical patent/WO2008122023A1/fr

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
    • B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
    • B01D53/9445—Simultaneously removing carbon monoxide, hydrocarbons or nitrogen oxides making use of three-way catalysts [TWC] or four-way-catalysts [FWC]
    • B01D53/945—Simultaneously removing carbon monoxide, hydrocarbons or nitrogen oxides making use of three-way catalysts [TWC] or four-way-catalysts [FWC] characterised by a specific catalyst
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
    • B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
    • B01D53/944—Simultaneously removing carbon monoxide, hydrocarbons or carbon making use of oxidation catalysts
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/14—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on silica
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/71—Ceramic products containing macroscopic reinforcing agents
    • C04B35/78—Ceramic products containing macroscopic reinforcing agents containing non-metallic materials
    • C04B35/80—Fibres, filaments, whiskers, platelets, or the like
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B38/00—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof
    • C04B38/0006—Honeycomb structures
    • C04B38/0009—Honeycomb structures characterised by features relating to the cell walls, e.g. wall thickness or distribution of pores in the walls
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2251/00—Reactants
    • B01D2251/20—Reductants
    • B01D2251/206—Ammonium compounds
    • B01D2251/2067—Urea
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/10—Noble metals or compounds thereof
    • B01D2255/102—Platinum group metals
    • B01D2255/1021—Platinum
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/10—Noble metals or compounds thereof
    • B01D2255/102—Platinum group metals
    • B01D2255/1023—Palladium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/10—Noble metals or compounds thereof
    • B01D2255/102—Platinum group metals
    • B01D2255/1025—Rhodium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/20—Metals or compounds thereof
    • B01D2255/207—Transition metals
    • B01D2255/20723—Vanadium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/50—Zeolites
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
    • C04B2111/00474—Uses not provided for elsewhere in C04B2111/00
    • C04B2111/00793—Uses not provided for elsewhere in C04B2111/00 as filters or diaphragms
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
    • C04B2111/00474—Uses not provided for elsewhere in C04B2111/00
    • C04B2111/0081—Uses not provided for elsewhere in C04B2111/00 as catalysts or catalyst carriers
    • 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 field of the present invention is the construction and use of filters and catalyzing filters for pollution control in an emission control system. More particularly, the present invention relates to a multifunction filter for use with an internal combustion engine.
  • Internal combustion engines are essential to modern life. These engines power our cars, trucks, delivery vehicles, emergency generators, manufacturing equipment, farming equipment, and innumerable other machines and processes. Internal combustion engines typically are powered using a hydrocarbon fuel. Most often, this fuel is derived from crude oil, and is in the form of gasoline, diesel, or other liquid fuel. The internal combustion engine has evolved over time to provide excellent performance characteristics, extended durability, and low cost of operation. Due to these characteristics, the internal combustion engine continues to be a main power source for manufacturing, commercial, industrial, transportation, and residential use.
  • an internal combustion engine typically combines a hydrocarbon fuel with air, and ignites the mixture to generate an explosive power that is converted into a kinetic mechanical energy.
  • hydrocarbon fuels and in particular fossil fuels, generates highly undesirable pollutants that harm the environment.
  • internal combustion engines generate volatile organic compounds, pollutant gases such as carbon monoxide and various derivatives of NOx, as well as soot and ash.
  • pollutant gases such as carbon monoxide and various derivatives of NOx
  • soot and ash pollutants
  • Different types of internal combustion engines have different environmental impacts. For example, diesel engines typically generate far more soot than the gasoline powered engine, while having less environmental impact with NOx.
  • Great strides have been made, primarily due to government regulation, to clean the exhaust from internal combustion engine systems.
  • the vehicle may have two, three, or even more separate catalytic converters for converting various pollutant gases into less dangerous materials.
  • a gas powered passenger vehicle currently (2007) does not typically provide separate filtration for particulate matter or soot, even though some recent studies have highlighted the formation of nano-particle soot and secondary organic aerosol emissions from such engines.
  • the vehicle also has a complex engine control system for monitoring air /fuel ratios, and making real-time adaptations to the engine and emission control system for improved emission control.
  • a typical diesel-powered truck a large particulate filter is now used for trapping soot and ash, and a sophisticated burn off control system is used for periodically regenerating the filter.
  • Such filtering requirements may apply to heavy duty, medium duty, or even light duty, depending on the particular regulatory jurisdiction.
  • the filter In the regeneration process, the filter is heated sufficiently to burn soot, sometimes in the presence of a catalyst, into relatively harmless exhaustible by-products.
  • after-treatment devices may have to be installed, as in-engine modifications and controls are not enough to meet the regulatory emission limits.
  • an additional separate catalytic conversion devices or canisters are provided for oxidation of unburnt hydrocarbons, carbon monoxide and for NOx reduction. Additionally, sometimes cleanup catalyst systems are also needed to reduce leakage of criteria or toxic pollutants.
  • NO x is the generic name for a group of highly reactive gases that contain varying amounts of NO and NO 2 .
  • NO x although colorless and odorless, has highly detrimental environmental effects. About half the NO x emissions in the world are emitted from motor vehicles, including gasoline and diesel engines. Other significant sources of NO x , are typically more stationary facilities, such as electric utilities, industrial, and commercial sources, where NO x reduction devices are readily incorporated. Motor vehicles provide a particularly difficult challenge due to the vast number of individual engines, the differences between engines, the changing environmental conditions at each engine, seasonal and geographic differences in fuels, and other unpredictable and dynamic environmental characteristics.
  • NO x has various detrimental environmental impacts, both to the environment generally and to human health in particular.
  • NO x and volatile organic compounds react with heat and sunlight to form ground-level ozone or smog.
  • Ground-level ozone and smog causes lung damage, and has adverse effects on those most susceptible to decreases in lung function, such as, asthmatics, and people who work or exercise outside.
  • Smog and ground-level ozone also has a negative impact on vegetation and reduces crop yields.
  • NO x also reacts with sulfur dioxide in the atmosphere to form acid rain, which falls to Earth with rain, fog, snow, or as dry particles.
  • NO x also has a more direct affect on humans, by directly deteriorating the respiratory system. NO x reacts with ammonia, moisture, and other compounds in the air to form nitric acid and related particles. These particles damage lung tissue, and the small size of the particles penetrate deeply into sensitive parts of the lungs and cause or worsen potentially fatal respiratory diseases such as emphysema and bronchitis. With all these known dangers to NO x emissions, governmental agencies around the world are taking strong action to reduce the levels of NO x emitted into the atmosphere by internal combustion engines.
  • NO x traps have also been proposed that are composed of materials (often barium salts) that store NO x under lean conditions, and then periodically release and catalytically reduce the stored NO x to CO 2 and N 2 during rich conditions.
  • materials often barium salts
  • SCR selective catalytic reduction
  • SCR systems meter a precise amount of a chemical agent into the engines exhaust system. Often, this reagent is urea. The urea is thoroughly mixed with the hot exhaust gas, and decomposes into ammonia. The resulting gas is subsequently reacted with a catalyst to generate nitrogen and water vapor.
  • FIG. 20 and 21 Such a known SCR system is illustrated in figures 20 and 21.
  • an engine generates an untreated exhaust gas which is mixed with a gas phase additive prior to being received into an SCR catalyst device.
  • the gas phase additive is typically urea (NH 2 ) 2 CO, which reacts with the hot exhaust gas to form ammonia NH 3 , and carbon dioxide.
  • the gases are received into an SCR catalyst, where the ammonia reacts with NOx in the presence of a catalyst material to be reduced into relatively harmless nitrogen gas. Selection and application of the catalyst is particularly important in systems for mobile internal combustion engines.
  • the SCR catalytic device is placed in relation to other emission control devices.
  • operating the SCR catalyst at low temperatures may present problems both in conversion efficiency and in catalyst durability or survivability.
  • the catalyst typically does not reach full efficiency until a relatively high operating temperature has been reached.
  • the SCR catalyst material may be consumed or deactivated during some low-temperature reactions, so continual or prolonged operation in low temperatures may substantially and permanently degrade the performance of the SCR catalyst.
  • Such a system is illustrated in figure 20, where the SCR catalyst is positioned close to the internal combustion engine. In this way, NO x reduction is performed in the SCR catalyst, and then the reacted exhaust gas is sent to a particulate filter where soot is removed.
  • the exhaust emitted from the internal combustion engine typically contains levels of soot, which may act to clog the SCR catalyst, react or deactivate the catalyst material, or otherwise interfere with effective NO x control.
  • soot may act to clog the SCR catalyst, react or deactivate the catalyst material, or otherwise interfere with effective NO x control.
  • the arrangement shown in figure 21 has a longer light-off period before the SCR catalyst reaches its preferred operational temperatures. In this way, ammonia may slip through the system, catalyst material may be permanently deactivated, and the level of overall NO x reduction is undesirable.
  • FIGS 20 and 21 also show the SCR system having an engine control system.
  • the engine control system typically is a closed loop control system having feedback from measurements taken at various points along the exhaust path. However, for less stringent NO x control, an open loop control system may be sufficient.
  • each SCR catalyst has a different preferred operating temperatures.
  • platinum is most effective in a narrow band of temperatures below about 250 0 C, with performance quickly deteriorating above that range. Accordingly, a platinum-based SCR catalyst must be positioned to maintain operating temperature in a relatively narrow band. Further, this narrow window for temperature control adds expense and complexity to the overall process design, especially to the engine control system.
  • Vanadia has a higher and wider operational band than platinum, effectively reducing NO x from about 300 0 C to about 400 0 C. Even higher temperatures are effective for zeolite (especially Cu, Fe or otherwise substituted zeolites), which is efficient at temperatures over 400 0 C.
  • vanadia and zeolite have wider operating bands, and are therefore more easily integrated into a mobile emission control system, their higher initial temperature requirements may lead to undesirable ammonia slip and efficient or effective NOx control at lower temperatures, for example, at startup. Sophisticated engine control is still required even with vanadia or zeolite SCR systems, as both catalysts degrade at elevated temperatures.
  • an oxidation catalyst device may be provided for conversion of hydrocarbon gases and carbon monoxide into carbon dioxide and water, and in some cases, more than one oxidation catalyst will be provided.
  • a typical passenger vehicle may have an oxidation catalyst near the internal combustion engine for providing oxidation immediately after startup and a main oxidation catalysts that performs higher levels of oxidation after an operational temperature is reached.
  • another oxidation catalyst may be provided after the SCR device to oxidize ammonia slip, which is present due to imperfect conversion within the SCR catalyst.
  • urea is provided, typically in a water- soluble liquid, although some applications may allow for a solid phase or in- situ generated urea.
  • the urea solution is pumped from a urea tank and sprayed through an atomizing nozzle into the exhaust gas. Thorough mixing of the urea with the exhaust gas and a uniform flow distribution is important to achieving high rates of urea decomposition. Accordingly, a separate mixing device or area may be provided to facilitate improved ammonia formation. Also, a dedicated hydrolysis catalyst may be installed to further facilitate the hydrolysis of urea into ammonia.
  • the SCR catalyst device is sized to assure ammonia molecules and NOx molecules are brought into contact with the catalyst. Indeed, some early SCR catalyst used very low space velocities to provide for high NO x reductions and low ammonia slip, but this resulted in very large catalytic device sizes. SCR catalyst device size may be reduced by increasing cell densities or loading more catalyst material into the device. However, increasing cell densities or providing more catalyst material both act to detrimentally affect backpressure characteristics, thereby reducing fuel efficiency and engine performance. [0023] Therefore, there exists a need to provide emission control devices that can efficiently meet current and evolving emission standards for NOx, while minimizing the overall size, cost, and complexity of the emission control system.
  • the present invention provides a Selective Catalytic
  • FIG. 1 is a simplified block diagram of a emission control system in accordance with the present invention.
  • FIG. 4 is an enlarged sectional view of a channel wall structure for the substrate illustrated in figure 3;
  • FIG. 6 is an enlarged sectional view of a portion of a single channel wall for the substrate illustrated in figure 3;
  • FIG. 8 is a scanning electron microscope photograph showing a bonded fiber arrangement providing highly uniform pore structures
  • Fig. 9 is an illustration of a bonded fiber arrangement providing highly uniform pore structures
  • Fig. 12 is a flowchart of a process of forming a multifunction filter in accordance with the present invention.
  • Fig. 13 is a block diagram of a wall flow multifunction filter having multiple gas phase reaction zones.
  • Fig. 16 is a flowchart of the process of using an SCR multifunction filter in accordance with the present invention.
  • Fig. 19 is an enlarged sectional view of a portion of a single channel wall for an SCR-Filter
  • Fig. 20 is a block diagram of a known emission control system having a separate SCR catalyst and a separate particulate filter;
  • emission control system 10 is illustrated.
  • Emission control system 10 is constructed for use with an internal combustion engine to provide pollution control.
  • emission control system 10 advantageously may be used with gasoline, diesel, or other hydrocarbon-based internal combustion engine systems. Since the design and construction of engines, engine control systems, and general exhaust system components are well known, these will not be described in detail.
  • Emission system 10 has internal combustion engine 12 operating, for example, on diesel or gasoline fuel.
  • Engine 12 emits an untreated exhaust gas containing various pollutants, such as particulate matter, volatile organic compounds (VOC), and pollutant gases.
  • the untreated exhaust gas 19 is received into multi-function filter 14.
  • the multi-function filter 14 is a single discrete device for both filtering particulate matter from the untreated gas, and for facilitating catalytic conversion of one or more pollutant gases.
  • exhaust 21 from multi-function filter 14 is a filtered and catalyzed exhaust gas that complies with new and evolving emission control standards.
  • the filtering and catalyzing process has been enabled within a single multifunction filter assembly, reducing the size, complexity or cost of the other emission control devices in the exhaust systems. Accordingly, the multifunction filter 14 consumes less space in a vehicle, may be more conveniently integrated into vehicle aesthetics, and simplifies construction, maintenance, and repair.
  • engine control system 16 may monitor for an undue increase in back pressure in the multifunction filter 14, and in response, initiate a burn-off process to unload accumulated soot. It will be appreciated that engine control system 16 may monitor several aspects of emission control system, and may make adjustments according to the specific engine and exhaust design. Since the design and implementation of engine control systems is well known, engine control system 16 will not be described in detail.
  • Multifunction filter 14 has been constructed in a way that provides for both 1) highly efficient soot capture, as well as 2) enabling highly efficient gas catalyzing processes, while maintaining desirable back pressure, soot loading, soot unloading, and burn off characteristics.
  • emission control system 10 provides the first known multi-function filter capable of meeting stringent particulate and pollution control standards evolving in Europe, the United States, and in other countries around the world.
  • use of the multifunction filter 14 provides exceptional particulate and pollution control, while allowing internal combustion engines to meet performance requirements. For example, since multifunction filter 14 has exceptional back pressure characteristics, an associated internal combustion engine is able to more efficiently operate, and thereby maintaining or improving its fuel economy.
  • Multifunction filter 14 may be better understood with reference to figure 2, where a process 50 is described for operation on multifunction filter 14.
  • Multifunction filter 14 receives gas and particulate matter from an internal combustion engine as shown in block 52.
  • an additive may be reacted with the gas according to the particular gas-phase chemistry requirements as shown in block 54.
  • additive mixing is achieved in a mixing chamber prior to the gas being received into multifunction filter 55.
  • the additive is urea, which is decomposed to form ammonia by the heat from the exhaust. It will be appreciated that other catalyst processes may be used to facilitate improved ammonia formation.
  • ammonia (decomposed urea) is received into multifunction filter 55, where it reacts with nitrogen oxides in a reduction reaction to produce harmless nitrogen gas. It will also be appreciated that other additives may be used for creating other intermediate products for the removal of other pollutant gases according to application needs.
  • the exhaust gas is received into multifunction filter 55.
  • the multifunction filter 55 performs two distinct functions within a single substrate: first, highly effective soot capture; and second, it hosts an efficient gas-phase process.
  • multifunction filter 55 collects particulate matter using a highly uniform arrangement of pores. This highly uniform arrangement of pores has a relatively narrow distribution of pore sizes, as well as a generally open, inter-connected pore structure. This means that soot may be captured in a regular and uniform manner, and in some cases acts as an especially efficient cake filtering structure. With such a highly organized and arranged pore structure and size distribution, a very uniform loading of soot is achieved as shown in block 59.
  • this same pore structure contributes to a highly uniform unloading of soot as shown in block 61.
  • Uniform loading and unloading is advantageous, as it reduces undesirable channeling effects within the filter.
  • channeling effects occur within a filter as pores fill with trapped soot.
  • exhaust gases initially move along a path of least resistance, which typically will be through some set of relatively aligned and large pores. Operating in this state, the filter has a very low back pressure. However, as these initial pore networks clog with trapped soot, the exhaust gas is forced to take alternative paths.
  • the filter's backpressure may undergo an undesirable and sizeable increase, and the overall performance of the emission control system declines.
  • This temporary spike in backpressure wreaks havoc on the overall emission control system, complicating design and implementation, and causes irregular emission control performance.
  • the control strategies used for regenerating such filters are often under-utilizing the filter to make sure no backpressure spikes are observed.
  • the more regular and uniform distribution provided in multifunction filter 55 avoids much of his channeling effect, thereby maintaining efficiency over the loading and unloading process.
  • the open pore structure of multifunction filter 55 also allows gases to flow more uniformly and freely into internal areas of the multifunction filter. It also makes the porosity inside the wall fully accessible for catalyst loading and gas permeation.
  • the filtered gas is reacted with one or more catalysts that have been disposed on the internal arrangement of pores.
  • the arrangement of pores within the multifunction filter is also a generally uniform arrangement, and is constructed as a highly open cell network of pores.
  • a washcoat is disposed on to the substrate surface, which facilitates better adhesion and distribution of the catalyst or catalysts.
  • the uniform nature of the pore structure within the multifunction filter enables a uniform loading of the washcoat and catalyst as shown in block 65. Further, because of the open pore, interconnected pore network, the washcoat and catalyst may be disposed at very high loading levels. These high loading levels are highly advantageous for efficient catalyst processes, as well as desirable to assure long-term survivability.
  • substrate 100 may advantageously be used in a multifunction filter, such as multifunction filter 14 described with reference to figure 1. While substrate 100 may be manufactured in alternative ways, extrusion has been found to be a particularly efficient and effective process. Generally, the extrusion process mixes together fibers or fiber precursors with pore formers, plasticizers, and fluids to form an extrudable mixture at the proper rheology. The extrudable mixture is then forced through the die of an extruder, thereby generating a green substrate having a honeycomb form. The green substrate is first dried to remove fluids, and then further heated to remove pore formers, volatile organic and inorganic materials, and finally to form a bonded fibrous structure.
  • the bonded fibrous structure may be manufactured in different ways.
  • the bonded fibrous structure may be constructed as an arrangement of individual fiber or fiber-like structures that are bonded together at overlapping nodes.
  • fiber structures include individual fibers, fibers formed into multi-fiber bundles or multi-fiber clumps. These collections of fiber structures bond with other fibers, bundles, or clumps to form a bonded fibrous structure having a highly desirable open, inter-connected pore network.
  • substrate 100 has many channels formed in a honeycomb pattern. This honeycomb may have a channel density of, for example, 100 to 900 cells per square inch. In some cases where high flow rates are required, even smaller cell densities, as low as 10 cells per square inch, may be used as well. It will be understood that other cell densities may be used for other particular applications. In a particular construction, substrate 100 has alternating channels blocked or plugged at each end.
  • an inlet channel 107 receives a gas flow, and the gas flows through channel walls into one or more output channels 109. The gas then continues down the outlet channel until it is exhausted.
  • this type of channel arrangement is referred to as a "wallflow" filter construction.
  • a washcoat and catalyst is applied to substrate 100 for converting one or more pollutant gases to a less harmful substance.
  • the substrate may host a single type of catalyst, either in a relatively even loading from the inlet side 111 to the outlet side 112, or may be applied with a gradient loading. In this way, a heavier loading may be provided toward one end, while a lesser loading is applied at the other end. Also, the substrate is capable of hosting two or more different catalysts.
  • a first catalyst is disposed toward the inlet side 101 of the filter, and the second catalyst may be disposed toward the outlet end 102.
  • the first catalyst may be injected or received through the inlet side 101 openings
  • the second catalyst may be injected or received through the outlet side 102 openings.
  • multiple catalysts may be layered on the fiber structures, or, cell walls may have multiple zones, with each zone having its own catalytic purpose.
  • the surface adjacent to an inlet wall may have a catalyst for assisting in lower temperature soot burn-off
  • the interior of the channel wall may have a catalyst to assist in NOx reduction
  • an area adjacent to the outlet wall may have a cleanup or oxidation catalyst. In this way, a single substrate may efficiently provide or multiple catalytic processes.
  • Figure 4 shows an enlarged cross-section of part of the honeycomb structure of substrate 100.
  • Enlargement 110 shows inlet channel 107 adjacent to several output channels, including outlet channel 109.
  • Each of the channel walls 111 is a bonded fibrous structure.
  • Each inlet channel wall has a zone 113 having a particulate loading area having a highly uniform pore structure.
  • soot is the most common particulate, this will be general referred to as a soot capture zone.
  • the soot capture zone extends from the surface of the channel wall into the initial set of pores.
  • the depth of the soot capture zone will generally be a function of the pore- size, which can be set by changing the size or shape of pore-formers and fibers etc. For example, a larger pore arrangement will result in a fiber structure that acts more like a depth filter, whereas an arrangements of smaller pores will function more as a cake filter.
  • the bonded fibrous structure has a pore structure arranged for an even loading or unloading of soot. This even loading reduces undesirable channeling effects for an operating multifunction filter.
  • Each of the channel walls also has a gas-phased zone in an interior area.
  • the gas-phased zone also has a highly uniform open pore structure, although the structure may vary from the pore structure in the soot capture zone.
  • the open pore structure within the gas-phase zone enables an unusually heavy loading of washcoat and catalyst. In this way a highly efficient and survivable multifunction filter may be made.
  • the catalyst of choice is platinum, although other catalysts may be used. It will also be appreciated that more than one type of washcoat or more than one type of catalyst may be used. In this way, a single multifunction filter is able to filter and react to or more pollutant gases.
  • the soot collection zone may also be coated in the same or a different catalyst.
  • the soot collection zone may also be coated with a washcoat and platinum, which assists in low temperature soot oxidation, although other catalysts may be selected that also help in the regeneration of soot.
  • FIG. 6 shows yet a further enlargement of a channel wall 225 for a multifunction filter substrate.
  • Filter wall 225 is constructed as a bonded fibrous substrate 227.
  • the bonded fibrous substrate 227 has two distinct zones, which may or may not be contiguous.
  • a first soot capture zone 229 has a highly uniform pore structure and arrangement, as well as a reasonably narrow pore-size distribution.
  • a second gas-phase conversion zone 231 is found within the channel wall.
  • the gas-phase zone also has a highly uniform pore structure, although the pore structure may be different from that of the soot capture zone 229.
  • Exhaust gas is received at the inlet channel wall, typically from an internal combustion engine.
  • the exhaust gas typically has both particulate matter and pollutant gases.
  • the exhaust gas first passes through the soot capture zone 229, where the soot 233 is captured at or near the surface of the inlet channel wall.
  • the filtered gas continues through to the gas-phase zone 231, where the gas pollutant molecules contact catalyst, and are converted to less harmful gases.
  • CO may be converted to CO 2 in an oxidation process, or NOx may be converted in a NOx reduction process.
  • the filtered and reacted gas is then exhausted into outlet channel 235.
  • another gas conversions zone 232 may be layered in the channel wall. The second zone may be used to support conversions of a second pollutant gas.
  • Figure 7 shows a simplified diagram of a channel wall 250 similar to channel wall 225 described with reference to figure 6.
  • Channel wall 250 has is positioned between an inlet channel 251 and an outlet channel 259.
  • the channel wall 250 is a bonded fibrous substrate, having individual fibers 258, fiber bundles 257, and clumps of fibers 255 that are bonded together to form an open pore network.
  • Channel wall 275 is a cross- sectional view showing an inlet channel 276 and an outlet channel 284.
  • the channel wall 275 is a bonded fibrous structure 276, having individual fibers 288, fiber bundles 284, and fiber clumps 289 bonded together in an open pore network.
  • wall 275 uses fibers, it will be understood that other materials may be used to effect the functionality of fiber. For example, fiber- like structures may be introduced in an extrusion mix, with fiber-like structures formed during the sintering process. Accordingly, for the multifunction filter, it is the unique functional characteristics of the resulting bonded structure that is most meaningful, since there are many ways to commercially manufacture such a fibrous bonded structure.
  • soot capture zone 277 In operation, and exhaust gas is received from the inlet channel 276, which passes through the soot capture zone 277, where soot captures at or near the surface.
  • the filtered gas continues through to the gas-phase zone 279, where gas molecules react with catalyst to form less harmful materials.
  • the gas is then exhausted into outlet channel 284.
  • the outside wall 281 provides additional structural integrity for the channel wall 275.
  • the soot capture zone 277 has a highly uniform pore structure, but is different than the highly uniform pore structure in the gas-phase zone 279.
  • mullite fibers were mixed with approximately 44 micron (325 mesh) particle size carbon as a pore former, colloidal silica, organic and inorganic binders and plasticizers, along with water. The mixture was aggressively and thoroughly mixed to an extrudable rheology.
  • a piston/ram extruder was used to extrude a green substrate at 200 cells per square inch. The green substrate was dried in an RF oven, and then heated to about 1000 degrees Celsius for approximately 28 hours to burn out organic materials, and sintered at 1500 degrees Celsius for about one hour. After cooling, the multifunction filter can be coated with washcoat, having one or more catalysts applied, and be secured into a can, canister, or other container.
  • Cell wall 300 shows a cell wall loaded with washcoat and catalyst. Accordingly, fibers 306 are heavily loaded with washcoat and one or more types of catalyst. Even though the fibers, fiber bundles, and fiber clumps are heavily loaded with washcoat and catalyst, an effective soot capture zone 302 is present, and the gas-phase zone 304 allows for relatively unrestricted flow. In this way, even when fully loaded with catalyst and washcoat, a highly efficient multifunction filter is provided, with both excellent back pressure characteristics and effective emission control. It will be appreciated that washcoat and catalyst loading will be determined according to application specific requirements, including the level of conversion required within the filter, the size of the filter, the expected flows, and the expected life. Generally, the need for heavier catalyst loading will increase as more demanding emission requirements come into effect.
  • the multi-function filter may be loaded with washcoat and catalyst at a loading rate of 10 grams per cubic foot, 20 grams per cubic foot, and 30 grams per cubic foot or more. In some instances, washcoat and catalyst loadings of 10 to 400 grams per cubic foot may be necessary. It will be appreciated that heavier catalyst loadings may be desirable to support multiple catalysts, to support conversions that consume or degrade catalyst, or to allow for more efficient conversions for slower reactions. By enabling a heavier loading of catalyst, the multifunction filter allows a single substrate to perform functions previously implemented only in multiple substrates in multiple devices. Importantly, even with these heavy load requirements, the resulting multifunction filter may operate with an impact on back pressure that is 0% to 50% increase over the back pressure of the filter without the washcoat and catalyst. This means, that even when fully loaded with washcoat and catalyst, the multi-function filter does not cause an undue backpressure to the engine. In this way, the overall engine system is able to maintain fuel efficiency and meet performance goals, even when the multifunction filter is heavily loaded.
  • exhaust gas is received from an internal combustion engine as shown at block 326.
  • a gas- chemistry additive may be added as shown at 327. This additive is mixed with exhaust gas to form a material that is more easily reacted, filtered, or catalyzed within the multifunction filter 329.
  • the gas is received into the multifunction filter 329 where a soot collection zone 331 first captures soot or other particles or particulate matter.
  • the filtered gas is then passed into a gas- phase zone as shown at block 333. In gas-phase zone 333, pollutant gas molecules contact catalyst, and react to form less harmful materials.
  • FIG. 11 shows a multifunction filter 400 having a single bonded fibrous substrate 402.
  • the fibrous substrate 402 is heavily loaded with washcoat and catalyst as shown at block 404. Although the particular level of loading is application-specific, loads of 10 to 400 grams per cubic foot or more may be advantageously used.
  • the multifunction filter 452 also has a set of soot collection zones 406, typically positioned on the surface walls for inlet channels of the filter.
  • the multifunction filter 402 also has a set of gas reaction zones 408. These gas reaction zones are typically inside the channel walls of the multifunction filter. Prior to washcoat and catalyst loading, the fibrous substrate 402 typically has a porosity of about 55% to about 70%. It will be appreciated other porosities may be selected according to application needs. Importantly, loading or unloading soot from the soot collection zone has an insignificant channeling effect.
  • Process 425 uses an extrusion process to extrude a honeycomb filter substrate as shown in block 428.
  • This honeycomb substrate has a fiber arrangement on the surface walls particularly constructed to have a highly uniform pore structure for collecting target particular matter as shown at block 430.
  • specific fiber diameters, sizes of pore formers, and amounts of organic material are selected to construct a pore structure for the target particular matter.
  • Fibers are also arranged inside the walls to form a uniform open, inter-connected pore network for facilitating gas contact with the catalyst as shown at block 431.
  • the fibrous substrate is made into a wallflow structure by plugging every other hole at each end as shown in block 432.
  • the green substrate is dried and sintered into a bonded fibrous block as shown in 436.
  • the substrate is then loaded with a heavy load of washcoat and catalyst as shown in block 438.
  • the loading of washcoat and catalyst may exceed even 30 grams per cubic foot.
  • Multifunction filter 450 has a bonded fibrous substrate 452 as previously discussed.
  • the multifunction filter 452 has a set of soot collection zones 465 arranged to capture soot in a highly uniform arrangement of pores.
  • the multifunction filter 452 also has a set of gas-phase reaction zones.
  • the filter has multiple zones, with each zone having a catalyst for reacting a different pollutant gas.
  • zone 460 has a washcoat and catalyst for reacting a first pollutant gas
  • zone 461 has a different catalyst for reacting another pollutant gas.
  • an inlet gas 454 is filtered through one or more soot collection zones 465 and then received into the gas-phase reaction zones.
  • FIG 14 shows a process 475 for manufacturing the multifunction filter 450 illustrated in figure 13.
  • Process 475 extrudes the fibrous honeycomb filter substrate as shown in block 477.
  • the extrusion process arranges fibers in the soot collection zone 479, as well as fibers in the gas-phase zone 481. Every other hole is plugged to form a wallflow structure 483, and the block is dried and sintered into a bonded fibrous substrate.
  • a washcoat may be applied to the entire substrate, and then a first catalyst is applied through the inlet channels as shown at block 487.
  • a second catalyst may be applied through the outlet channels as shown in block 489.
  • a soot collection zone is at or near the surface of inlet channel walls, a first gas-phase zone exists inside channel walls, and a second gas-phase zone exists at or near the outlet channel wall. It will be appreciated that other processes may be used for applying washcoat and catalyst to a bonded fibrous substrate.
  • the multifunction filter is intended to be adapted to particular and specific emission control requirements.
  • the multifunction filter may have its soot collection zone constructed for capturing one or more specific particle sizes, while the gas-phase zone may be arranged to support the loading of a specific washcoat and catalyst. Accordingly, the multifunction filters described in figures 1 through 14 should not be limited to any particular structure, engine, fuel type, particular matter, or catalyst.
  • SCR soot-filter 504 performs at least two distinct functions. First SCR soot-filter 504 traps particulate matter in a soot collection zone, and second, to SCR soot-filter 504 has a gas-phase zone that reacts NOx with ammonia in the presence of a catalyst to reduce the NOx to harmless nitrogen gas. The chemical reaction of this reduction can be expressed in at least three ways:
  • SCR soot-filter 504 may perform additional tasks, such as assist in hydrolysis or oxidation reduction. After passing through SCR soot-filter 504, the filtered and catalyzed exhaust gas 513 is passed to other emission control devices, or may be exhausted to the atmosphere through a muffler, sound abatement, or other device.
  • urea 508 is provided as a water-soluble solution.
  • urea may be provided in other liquid or solid forms, or generated (from H 2 ) on board using fuel reformers. Further, it will be understood that the urea 508 may be mixed with other additives, for example, to provide an anti-freeze effect to lower the urea solution freezing point.
  • the catalyst may be provided as platinum, zeolites, vanadia, or other appropriate catalyst, such as copper or iron-based formulations. It will be appreciated that as more effective and efficient catalyst products are found, they may be advantageously used in SCR soot- filter 504.
  • the SCR filter system 500 enables a single substrate, in a single canister, to be installed on a vehicle such that the vehicle meets 2010 EPA and Euro V NOx /soot standards.
  • the 2010 EPA and EuroV standards are complex and cover a wide range of vehicles, but a few specific examples will illustrate some to the vehicles that may benefit from the use of the SCR filter system 500. It will be appreciated that other classes of vehicles may benefit, and that system 500 may be used to meet other current or evolving standards using a single substrate.
  • EPA US
  • EuroV EuroV
  • Process 525 may operate on an SCR filter system, such as SCR filter system 500 described with reference to figure 15.
  • an engine control system sets an engine to operate at a desirable fuel ratio and settings as shown in block 527.
  • the engine control system may adjust the amount of NOx initially created, as well as adjust the amount of oxygen available for subsequent devices and processes in the exhaust system.
  • Urea is injected into the exhaust system as shown on block 529.
  • the urea is thoroughly mixed into the hot exhaust gas so that it decomposes to form ammonia.
  • the reactants in the exhaust gas flow into an SCR-filter as shown in block 531.
  • the SCR soot-filter is a wallflow filter having a honeycomb pattern with alternating inlet and outlet channels.
  • the filter has a soot capture zone on or near the inlet walls of the inlet channels as shown in block 533.
  • the soot capture zone is formed using a highly uniform arrangement of pores. This highly uniform arrangement of pores facilitates an exceptionally even loading of soot particles, which minimizes any undesirable channeling effects.
  • Process 550 extrudes a fibrous honeycomb filter substrate as shown in block 552.
  • these fibers may be ceramic, metal, silicon carbide, or other fiber material.
  • the fiber it may be provided as fiber strands, or may be provided as precursors that form a fiber-like structure during a sintering process.
  • the extrudable mixture also has pore formers, plasticizers, fluids, and other materials mixed to a rheology for proper extruding as previously described.
  • the honeycomb substrate has a fiber arrangement on the surface walls particularly constructed to have a highly uniform pore structure for collecting soot as shown at block 553.
  • the fibrous substrate is made into a wallflow structure by plugging every other hole at each end as shown in block 556.
  • the green substrate is dried and sintered into a bonded fibrous block as shown in 558.
  • the plugging process of block 556 may be performed after the sintering process of a 558, depending on manufacturing process.
  • the bonded fibrous structure may be formed in different ways.
  • the bonded fibrous structure may be constructed as an arrangement of individual fiber or fiber- like structures that are bonded together at overlapping nodes.
  • fiber structures include individual fibers, fibers formed into multi- fiber bundles or multi-fiber clumps.
  • the particle size of the washcoat/catalyst, or the suspension slurry concentrations may be adjusted depending on the coating levels and penetration into wall required.
  • the catalyst may be selected for its ammonia /NOx conversion efficiency, operating temperature /chemical ranges, and lifecycle characteristics. It will be understood that more than one type of catalyst may be used, and different types of catalyst may work better in different specific applications. For example, platinum may work more efficiently in relatively low temperature applications that can be tightly controlled, whereas vanadia or zeolites may be more effective in other hotter and less controlled applications. It will be appreciated that washcoat and catalyst loading will be determined according to application specific requirements, including the level of conversion required within the filter, the size of the filter, the expected flows, and the expected life.
  • the hydrolysis zone is placed at or adjacent to the soot capture zone, and provides for more complete decomposition of urea to ammonia before the gas is received into the first gas-phased reaction zone.
  • the second gas-phase zone may also provide an ammonia-slip catalyst for conversion of ammonia that is not consumed in the NOx reaction processes. In some cases, excess ammonia will be created, and if not reacted, will be emitted as a pollutant gas. Accordingly, the ammonia-slip zone enables ammonia conversion on the same substrate as the NOx reduction, eliminating the need for some separate down-stream slip converter.
  • the second conversion zone may be positioned separately and distinctly from the NOx conversion zone, or some overlap may be accommodated.
  • multiple catalysts may be layered in the same area of the fibrous substrate.
  • multiple catalysts are disposed on the same substrate, which facilitate multiple catalytic conversions, or are arranged such that one conversion supports the next conversion.
  • multiple conversion zones may be in separate areas of the substrate, may be arranged as stacked layers in the substrate, or may be layered as multiple catalysts disposed on the same substrate. It will be understood that other zone arrangements and uses may be substituted.
  • Channel wall 602 has an exhaust gas from an internal combustion engine being mixed with a water soluble urea at a mixing area.
  • the heat of the exhaust decomposes the urea into carbon dioxide and ammonia, as well as other byproducts according to known chemical processes.
  • This reacted gas is received at an arrangement of highly uniform pores at an inlet channel wall.
  • Soot 606 in the gas is evenly collected at this uniform pore structure, providing for a highly uniform loading process.
  • This highly uniform soot-loading process at the soot taking zone 604 avoids undesirable channeling effects.
  • the channel wall has a single soot collection zone 604 and a single gas conversion zone 608.
  • additional zones may be provided to support additional filtering and catalytic requirements.
  • FIG 19 an enlarged cross section of a channel wall structure 650 is illustrated.
  • the channel wall has an exhaust gas from an internal combustion engine being mixed with a water soluble urea at a mixing area. The heat of the exhaust decomposes the urea into carbon dioxide and ammonia, as well as other byproducts according to known chemical processes. In some cases, additional conversion may be desired, so a hydrolysis catalyst gas-phase zone 655 is provided at the inlet channel wall.
  • This hydrolysis gas-phase zone is coated with sufficient washcoat and catalyst to assist in decomposing the urea into ammonia.
  • the inlet channel wall also has a soot caking zone 652, which has a highly uniform arrangement of pores for efficiently trapping soot 653.
  • the soot caking zone 652 is typically at or near the inlet channel wall. Depending on how the hydrolysis catalyst was deposited, the hydrolysis gas-phase zone typically will extend from the surface of the inlet channel wall into the channel wall.
  • the gas After passing through the hydrolysis gas-phase zone 655, the gas is received into an NOx/ammonia conversion zone 660.
  • the NOx /ammonia conversion zone 660 has been heavily loaded with a washcoat and an appropriately selected catalyst.
  • the NOx/ammonia conversion zone 660 is constructed to have a highly uniform open cell network, which facilitates a heavy loading of washcoat and catalyst, without providing an undue back pressure to the engine.
  • the catalyst has been selected according to efficiency requirements, as well as expected performance and environmental conditions. As previously described, this catalyst may be platinum, palladium, rhodium, zeolites, vanadia, barium oxide /nitrate or other NOx reduction/ammonia catalyst.
  • the catalyst assists in reacting NOx and ammonia to form nitrogen gas and water, which is passed into outlet channel 665.
  • the gases Prior to being received into the outlet channel, the gases pass through an oxidation gas-phase zone 663.
  • the uniformly arranged open pore structure adjacent to the outlet channel wall has been coated with a catalyst to assist an oxidation process, such as converting carbon monoxide to carbon dioxide. It will be appreciated with other types of catalytic processes may be supported.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Manufacturing & Machinery (AREA)
  • Combustion & Propulsion (AREA)
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  • Exhaust Gas After Treatment (AREA)

Abstract

L'invention concerne un filtre de réduction catalytique sélective (SCR) à utiliser dans des systèmes antipollution, par exemple, pour les gaz d'échappement issus d'un moteur à combustion interne. Ce filtre SCR comprend un substrat composé de structures de fibres liées qui coopèrent pour former un réseau à cellules ouvertes hautement uniforme et pour permettre d'obtenir un agencement uniforme de pores. Le substrat se présente généralement sous forme de structure alvéolaire à écoulement de paroi, et dans un exemple, est fabriqué au moyen d'un procédé d'extrusion. Ainsi, le substrat comprend plusieurs parois de canal, chacune présentant une surface d'entrée et une surface de sortie. La surface d'entrée présente un agencement uniforme de pores formant une zone de capture de suies, dans laquelle des suies et d'autres matières particulaires peuvent être capturées à partir des gaz d'échappement. Un catalyseur de conversion de NOx est disposé à l'intérieur de la paroi de canal, dans lequel les NOx et l'ammoniac présents dans les gaz d'échappement sont convertis en substances moins nuisibles.
PCT/US2008/059073 2007-04-02 2008-04-02 Filtre de réduction catalytique sélective et procédé d'utilisation de ce dernier WO2008122023A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US11/695,585 US20080236145A1 (en) 2007-04-02 2007-04-02 Emission Control System using a Multi-Function Catalyzing Filter
US11/695,585 2007-04-02
US11/736,388 2007-04-14
US11/736,388 US20080256936A1 (en) 2007-04-17 2007-04-17 Selective Catalytic Reduction Filter and Method of Using Same

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WO2010051983A1 (fr) * 2008-11-05 2010-05-14 Süd-Chemie AG Réduction de particules avec un catalyseur combiné scr et contre les dégagements de nh3
WO2012135871A1 (fr) * 2011-03-29 2012-10-04 Basf Corporation Filtre multicomposant pour maîtrise des émissions
EP2522419A1 (fr) * 2011-05-13 2012-11-14 Kabushiki Kaisha Toyota Jidoshokki Dispositif de catalyseur
WO2013007468A1 (fr) * 2011-07-13 2013-01-17 Haldor Topsøe A/S Procédé de revêtement d'un filtre à particules catalysé et filtre à particules
WO2013007467A1 (fr) * 2011-07-13 2013-01-17 Haldor Topsøe A/S Filtre à particules catalysé et procédés de revêtement de filtre à particules
WO2018229214A1 (fr) * 2017-06-16 2018-12-20 Umicore Ag & Co. Kg Filtre à suie et hydrolyse d'urée combinés

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WO2005113126A1 (fr) * 2004-04-28 2005-12-01 Geo2 Technologies, Inc. Composites non-tissés et produits et procédés afférents
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US6203770B1 (en) * 1997-05-12 2001-03-20 Clean Diesel Technologies, Inc. Urea pyrolysis chamber and process for reducing lean-burn engine NOx emissions by selective catalytic reduction
US7067092B2 (en) * 1997-09-09 2006-06-27 Accentus Plc Treatment of gaseous emissions
WO2005113126A1 (fr) * 2004-04-28 2005-12-01 Geo2 Technologies, Inc. Composites non-tissés et produits et procédés afférents

Cited By (14)

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Publication number Priority date Publication date Assignee Title
US8883100B2 (en) 2008-11-05 2014-11-11 Sued-Chemie Ip Gmbh & Co. Kg Particle reduction with combined SCR and NH3 slip catalyst
WO2010051983A1 (fr) * 2008-11-05 2010-05-14 Süd-Chemie AG Réduction de particules avec un catalyseur combiné scr et contre les dégagements de nh3
US9145809B2 (en) 2011-03-29 2015-09-29 Basf Corporation Multi-component filters for emissions control
CN103687661A (zh) * 2011-03-29 2014-03-26 巴斯夫公司 用于排放物控制的多部件过滤器
US8722000B2 (en) 2011-03-29 2014-05-13 Basf Corporation Multi-component filters for emissions control
WO2012135871A1 (fr) * 2011-03-29 2012-10-04 Basf Corporation Filtre multicomposant pour maîtrise des émissions
EP2522419A1 (fr) * 2011-05-13 2012-11-14 Kabushiki Kaisha Toyota Jidoshokki Dispositif de catalyseur
WO2013007468A1 (fr) * 2011-07-13 2013-01-17 Haldor Topsøe A/S Procédé de revêtement d'un filtre à particules catalysé et filtre à particules
WO2013007467A1 (fr) * 2011-07-13 2013-01-17 Haldor Topsøe A/S Filtre à particules catalysé et procédés de revêtement de filtre à particules
CN103796757A (zh) * 2011-07-13 2014-05-14 赫多特普索化工设备公司 催化颗粒过滤器及涂覆颗粒过滤器的方法
RU2609005C2 (ru) * 2011-07-13 2017-01-30 Хальдор Топсеэ А/С Способ приготовления катализированного фильтра твердых частиц и фильтр твердых частиц
RU2609025C2 (ru) * 2011-07-13 2017-01-30 Хальдор Топсеэ А/С Катализированный фильтр твердых частиц и способ приготовления катализированного фильтра твердых частиц
WO2018229214A1 (fr) * 2017-06-16 2018-12-20 Umicore Ag & Co. Kg Filtre à suie et hydrolyse d'urée combinés
US11033858B2 (en) 2017-06-16 2021-06-15 Umicore Ag & Co. Kg Combined soot filter and urea hydrolysis

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