JP2020533511A - SCR catalyst membrane on particulate filter - Google Patents

Abstract

A coated particulate filter and a method for producing the same are disclosed. The particulate filter includes a honeycomb body having a plurality of porous flow path wall portions that define a flow path extending from the inlet end to the outlet end. The honeycomb body includes an upstream zone having a gas permeability in the upstream zone and a downstream zone having a gas permeability in the downstream zone arranged closer to the outlet end than the upstream zone. The SCR catalyst is present in the downstream zone with a local filling amount in the range of about 50 g / L to about 200 g / L, and the upstream zone gas permeability ranges from about 5 to about 90 times the downstream zone gas permeability. Is.

Description

priority

This application claims the priority benefit of US Provisional Patent Application Nos. 62/543, 643 filed on August 10, 2017 under Article 119 of the US Patent Act, the content of which is relied upon and by reference in its entirety. Incorporated herein.

The present disclosure relates generally to filters for engine exhaust, and more specifically, such as the exhaust stream of a diesel engine, a ceramic honeycomb filter for reducing NO _x and particulate matter in the engine exhaust stream, and to a method of fabricating the same ..

Contamination emissions from vehicles operated on either gasoline or diesel fuel have been improved using catalytic and particulate filter technology.

It is desirable to provide a DeNO _x catalyst configuration on the particulate filter to improve the catalyst utilization efficiency.

A first aspect of the present disclosure relates to a particulate filter, which comprises a honeycomb body having an inlet end and an outlet end, the honeycomb body extending axially from the inlet end to the outlet end and having an axial length L of the honeycomb body. _{It includes a} plurality of porous flow path wall portions that define a and further define a flow path extending from the inlet end to the outlet end. At least the first set of the flow path is closed, and the honeycomb body is further arranged in the upstream zone having the upstream zone gas permeability and the downstream zone closer to the outlet end than the upstream zone, and the downstream zone gas. Includes downstream zone with transmittance. Upstream zone has an axial length L _a shorter than the upstream zone axis length L _u of the honeycomb body, a plurality of porous flow path wall portion of the honeycomb body, to promote selective catalytic reduction of _the NO _x selective Including a catalytic reduction (SCR) catalyst, the SCR catalyst is present in the downstream zone packing with a local filling amount in the range of about 50 g / L to about 200 g / L, and the upstream zone gas permeability is downstream. It is in the range of about 5 to about 90 times the zone gas permeability.

Another aspect of the present disclosure relates to a lean burn engine exhaust system comprising the embodiments of the particulate filter described in the present disclosure.

Another aspect of the present disclosure relates to a method for producing a catalytic particulate filter, wherein the method is:
Inlet end and an outlet end, the honeycomb body comprising a plurality of porous flow path wall portion extends in the axial direction at the outlet end defining an axis length L _a of the honeycomb body from the inlet end, the subject selective catalytic reduction the (SCR) catalyst loading mass, a step of identifying, based on the axial length L _a of the honeycomb body, a plurality of porous flow path wall, to allow flow of gas into the outlet end from the inlet end It defines a flow path and includes a step in which at least the first set of flow paths is closed. The method may further by immersing the outlet end to the SCR catalyst slurry, the honeycomb body was coated to a-axis length L _a shorter length, subject SCR catalyst charge mass of the shaft length L _a of the honeycomb body 75% Including a step of providing a honeycomb body coated so as to be contained in less than.

Further features and advantages are set forth in the following detailed description, which is, in part, apparent to those skilled in the art, or in the following detailed description, claims, and attachments. It will be appreciated by implementing the embodiments described herein, including drawings.

It should be understood that both the schematic description so far and the detailed description below are merely exemplary and are intended to provide an overview or framework for understanding the nature and characteristics of the claims. .. The accompanying drawings are provided for further understanding and are incorporated herein by them in part. The drawings show one or more embodiments, and together with the description, serve to explain the principles and operations of the various embodiments.

It will be appreciated that the illustrations are intended to describe a particular embodiment and are not intended to limit this disclosure or the appended claims. Drawings are not necessarily to scale, and some features and lines of sight in the drawings may be exaggerated or outlined in order to be clear and concise.

The particulate filter according to one or more embodiments shown and described herein is schematically shown. A partial axial cross-sectional view of the particulate filter of FIG. 1 according to one embodiment shown and described herein is schematically shown. A partial axial cross-sectional view of the particulate filter of FIG. 1 according to another embodiment shown and described herein is schematically shown. It is a graph which shows the pressure drop by the soot adhesion with respect to various soot adhesion with respect to various filters. It is a graph which shows the pressure drop for the filter coated with various lengths. It is a graph which shows the relationship between NO _x conversion and a reaction temperature for various filters. It is a graph which shows the relationship between the NO _x conversion at 250 degreeC and the film length of a filter. It is a graph which shows the relationship between NO _x conversion and temperature for various coated filters.

Prior to describing some exemplary embodiments, it should be understood that the present disclosure is not limited to the detailed configurations and processing steps disclosed below. The disclosure herein can be carried out in other embodiments and can be carried out or carried out in various embodiments.

It should be noted that the terms "abbreviation" and "about" can be used herein to describe an inherent degree of uncertainty that may result from any quantitative comparison, value, measurement, or other expression. .. As used herein, these terms may also be used to describe the extent to which quantitative expressions may differ from the values described without changing the basic function of the subject.

As used herein, a "DeNO _x catalyst" is a catalyst that improves nitrogen oxides (NO _x ) from an exhaust stream that can be emitted from a stationary source or a mobile source such as a lean burn engine of a vehicle. Refer to. DeNO _x catalyst, the hydrocarbons are selectively promote _the NO _x reduction "lean the NO _x catalyst", and simply by nitrogen compounds such as generally referred ammonia or urea as "SCR catalyst", NO _x Includes catalysts that promote selective catalytic reduction (SCR).

Here, with reference to FIG. 1, a particulate filter according to one or more embodiments shown and described herein is schematically shown. A particulate filter is generally a honeycomb structure containing a plurality of parallel channels defined by intersecting channel walls. In the present specification, the terms "upstream side" and "downstream side" are used to describe the relative orientation of the zones of the particulate filter. As used herein, the term "upstream" refers to a zone that is closer to the inlet of the particulate filter than the compared zones. Similarly, as used herein, the term "downstream" refers to a zone that is closer to the exit end of the particulate filter than the compared zones. When using a particulate filter, the inlet end of the particulate filter receives the exhaust gas from the engine, the exhaust gas flows through the filter and exits the filter at the outlet end.

As used herein, the term "transmittance" refers to the ability of a fluid to flow through a particulate filter channel wall. In the embodiments and examples described in the present specification, the transmittance of the flow path wall portion can be calculated by the following formula.

However, u represents the speed at which the fluid passes through the flow path wall portion in m / s, κ represents the transmittance of the flow path wall portion in m ² , and μ represents the fluid. It is the viscosity, Δp is the pressure drop over the flow path wall portion in Pascal, and δ is the thickness of the flow path wall portion. After measurement of the particulate filter of known flow path wall thickness and, given the fluid of known viscosity, the velocity of the fluid flowing through the flow path wall and the pressure drop over the flow path wall, The transmittance of the wall can be calculated back. Instead, a pollometer can be used to identify the transmission of different zones of the particulate filter.

Here, with reference to FIG. 1, the particulate filter 100 is schematically shown. The particulate filter 100 can be used as a wall flow filter to remove particulate matter from an exhaust gas stream, such as an exhaust gas stream emitted from a lean burn engine such as a diesel engine. The nitrogen oxide compound (NO _x ) contained in the exhaust gas stream can also be reduced by using the particulate filter 100. The particulate filter 100 generally has an inlet end 102 and an outlet end 104, and includes a honeycomb body including a plurality of porous flow path wall portions 106, and the flow path wall portion is between the inlet end 102 and the outlet end 104. defining a plurality of flow channels 101 or cells extending further defines an axis length L _a of the honeycomb body. The particulate filter 100 may also include an outer skin layer 105 surrounding the plurality of flow paths 101. The exodermis layer 105 is formed as a retrofit exodermis layer by extrusion molding while forming the flow path wall portion 106, or by applying an exodermis forming adhesive to the flow path of the outer peripheral edge portion in the subsequent treatment. Can be done.

Further referring to FIG. 1, and here also referring to the axial cross-sectional views of the particulate filter shown in FIGS. 2 and 3, the plurality of flow paths 101 generally have a square cross section. However, in an alternative embodiment, the plurality of flow paths 101 of the particulate filter may have other cross-sectional configurations including rectangular, circular, elliptical, triangular, octagonal, hexagonal, or combinations thereof. For the honeycomb used in the particulate filter utilization, some channels are allocated as inlet channels 108 and some other channels are allocated as outlet channels 110. When arranged downstream from the lean burn engine as described above, the exhaust gas enters the particulate filter through the inlet flow path and exits the particulate filter through the outlet flow path. In some embodiments of the particulate filter 100, at least the first set of channels can be blocked by the closure 112. Generally, the closure 112 is arranged close to the end of the flow path 101 (ie, the inlet end 102 or the outlet end 104). The blockages are generally arranged in a predetermined pattern such as the checkerboard pattern shown in FIG. 1, and the flow paths are blocked every other flow path. As shown in FIG. 2, the inlet flow path 108 may be blocked at or near the outlet end 104, and the outlet flow path 110 may be blocked at or near the inlet end 102 of the flow path that does not correspond to the inlet flow path. .. Therefore, each flow path can be blocked only at or near one end of the particulate filter.

Although FIG. 1 generally shows a checkered occlusion pattern, it should be understood that an alternative occlusion pattern can be used in the honeycomb structure. Further, in some embodiments, as shown in FIG. 3, the second set of channels can be a non-blocking once-through channel 109. In these embodiments, the particulate filter 100 may be referred to as a scalable filter or a partial filter.

In the embodiments described herein, the particulate filter 100 can be formed with a particulate density up to about 600 (cpsi) (about 93 / cm ² ) channels per square inch. For example, in some embodiments, the particulate filter 100 may have a channel density in the range of about 100 cpsi (about 16 / cm ² ) to about 600 cpsi (about 93 / cm ² ). In some other embodiments, the particulate filter 100 ranges from about 100 cpsi (about 16 / cm ² ) to about 400 cpsi (about 62 / cm ² ), or from about 200 cpsi (about 31 / cm ² ) to about 300 cpsi. It can have a channel density in the range (about 47 / cm ² ).

In the embodiments described herein, the particulate filter 100 may have a thickness of more than about 4 mils (about 101.6 micrometers). For example, in some embodiments, the thickness of the flow path wall 106 can range from about 4 mils (about 101.6 micrometers) to about 30 mils (about 762 micrometers). In some other embodiments, the thickness of the flow path wall 106 can range from about 7 mils (about 177.8 micrometers) to about 20 mils (about 508 micrometers).

In the embodiment of the particulate filter described in the present specification, the flow path wall portion 106 of the particulate filter 100 has an uncoated open porous ratio (that is, the porous ratio before applying the coating to the honeycomb body)% P ≧ 35%. Can be provided before the coating is applied to the particulate filter 100. In some embodiments, the uncoated opening porosity of the flow path wall 106 can be 40% ≤% P ≤ 70% or the like. In another embodiment, the uncoated opening porosity of the flow path wall portion 106 may be 50% ≤% P ≤ 67% or the like.

Further, the flow path wall portion 106 of the particulate filter 100 is formed so that the pore distribution of the flow path wall portion 106 before coating (that is, without coating) has an average pore size ≤ 30 micrometers. Will be done. For example, in some embodiments, the average pore size can be ≥8 micrometers and less than 30 micrometers or ≤30 micrometers. In other embodiments, the average pore size can be ≥10 micrometers and less than 30 micrometers or ≤30 micrometers. In other embodiments, the average pore size can be ≥10 micrometers and less than 25 micrometers or ≤25 micrometers. Generally, particulate filters manufactured with an average pore size greater than about 30 micrometers have lower filtration efficiency, while particulate filters manufactured with an average pore size less than about 8 micrometers are wash coated with a catalyst. It can be difficult to penetrate the material into the pores. Therefore, in one or more embodiments, it is generally desirable to maintain the pore size of the flow path wall between about 8 micrometers and about 30 micrometers.

In the embodiments described herein, the honeycomb body forming the fine particle filter 100 is, for example, cordierite, silicon carbide, aluminum oxide, aluminum titanate, or any suitable for use in the use of fine particle filtration at high temperatures. Formed from ceramic materials such as other ceramic materials. For example, the particulate filter 100 can be formed from cordierite by mixing a batch ceramic precursor material that may contain a constituent material suitable for producing a ceramic article predominantly containing a cordierite crystalline phase. In general, suitable constituent materials for cordierite formation include combinations of inorganic components, including talc, silica-forming sources, and alumina-forming sources. The batch composition may further include clays such as kaolin clay. Cordierite precursor batch compositions may also contain organic components such as organic pore size agents that are added to the batch mixture to achieve the desired pore size distribution. For example, the batch composition may contain a pore-forming agent and / or starch suitable for use as another treatment aid. Instead, the constituent material may include one or more cordierite powders suitable for forming a sintered cordierite honeycomb structure by firing, and an organic pore-forming material.

The batch composition may further comprise one or more treatment aids, such as, for example, a bonding agent and a liquid solvent such as water or a suitable solvent. Treatment aids are added to the batch mixture to plasticize the batch mixture, generally improve the treatment, reduce drying times, reduce calcination cracks, and / or preferably honeycomb bodies. Helps to generate physical properties. For example, the bonding agent may include an organic bonding agent. Suitable organic bonding agents include water-soluble cellulose ether bonding agents such as methyl cellulose, hydroxypropyl methyl cellulose, methyl cellulose derivatives, hydroxyethyl acrylates, polyvinyl alcohol, and / or any combination thereof. By including the organic bonding agent in the plasticized batch composition, the plasticized batch composition can be easily extruded. In some embodiments, the batch composition may include one or more optional forming or processing aids, such as, for example, a lubricant that assists in extrusion of the plasticized batch mixture. An exemplary lubricant extrudes the batch ceramic precursor material after mixing the batch ceramic precursor material, which may include tall oil, sodium stearate, or other suitable lubricant, with a suitable treatment aid. After drying, a plurality of flow path wall portions including the inlet end and the outlet end form an unfired honeycomb body extended between the inlet end and the outlet end. Then, the unfired honeycomb body is fired with a firing schedule suitable for producing the fired honeycomb body. Next, at least the first set of flow paths of the fired honeycomb body is closed with the ceramic closing composition in a predetermined closing pattern, and the fired honeycomb body is fired again to ceramicize the closed portion to form the closed portion. Is fixed in the flow path.

Here, referring to FIGS. 2 and 3, in the particulate filter described in the present specification, the particulate filter is closer to the outlet end 104 than the upstream zone 120 having the upstream zone gas permeability and the upstream zone 120. Arranged and formed to have a downstream zone 140 having a downstream zone gas permeability.

In another embodiment (not shown), the upstream zone 120 may be offset from the inlet end 102 of the particulate filter 100. For example, in some embodiments, the upstream zone 120 may be separated from the inlet end 102 of the particulate filter 100 by a separation zone containing a coating disposed on the flow path wall 106. Generally, the axial length _{L u} of the upstream zone 120 is shorter than the axial length _{L a} of the honeycomb body of the particulate filter 100. In some embodiments, the axial length _{L u} of the upstream zone 120 may be less than 50% of the axial length _{L a} of the particulate filter 100. In other embodiments, the axial length L _u of the upstream zone 120 may be a 33% of the shaft length L _a of the honeycomb body to form a particulate filter 100. However, the axial length L _u of the upstream zone 120, such that the axial length L _u of the upstream zone 120 is shorter than the axial length L _a of the honeycomb body to form a particulate filter 100, forming a particulate filter 100 any percentage of axial length L _a of the honeycomb body which is to be understood that may be long.

In the embodiment of the particulate filter 100 described herein, the upstream zone 120 is uncoated. That is, the pores of the porous flow path wall portion 106 and / or the flow path wall portion 106 of the upstream zone 120 reduce the transmittance of the flow path wall portion 106 with respect to the fluid flowing through the inlet and / or outlet flow paths. Does not contain a film layer that can be used. However, in other embodiments (not shown), upstream unless the coating layer reduces the transmittance of the flow path wall of the upstream zone 120 to be lower than the transmittance of the flow path wall of the downstream zone 140. It should be understood that the pores of the channel wall 106 and / or the channel wall 106 of the side zone 120 may include a coating layer. In one or more embodiments, the plurality of porous flow path walls of the honeycomb comprises a selective catalytic reduction (SCR) catalyst that facilitates selective catalytic reduction of NO _x . The SCR catalyst is locally filled in the range of about 50 g / L to about 200 g / L so that the gas permeability of the upstream zone 120 is in the range of about 5 to about 90 times the gas permeability of the downstream zone 140. It is present in the filling of the downstream zone 140 in quantity. As used herein, the catalyst charge, or total catalyst charge, or total washcoat charge, or washcoat charge is the outer volume of the filter, i.e. the total length and diameter of the filter. The catalyst material per volume calculated from the outer dimensions is expressed in grams. Further, the local filling amount or the local catalyst filling amount is defined as a value obtained by dividing the total wash coat filling amount by a fraction F, where F is a value obtained by dividing the coating length by the total length.

The downstream zone 140 is located on the downstream side of the upstream zone 120 and generally extends axially toward the outlet end 104 of the honeycomb body forming the particulate filter 100. In one embodiment, as shown in FIGS. 2 and 3, the downstream zone 140 is directly adjacent to the upstream zone 120, and the downstream zone 140 is from the end of the upstream zone 120 to the exit end 104 of the particulate filter 100. Extends axially toward. In another embodiment (not shown), the downstream zone 140 may be separated from the upstream zone 120 by one or more intermediate zones located between the downstream zone 140 and the upstream zone 120. However, it should be understood that the downstream zone 140 is always located on the downstream side of the upstream zone 120, regardless of the distance between the downstream zone 140 and the upstream zone 120.

Similarly as described above upstream zone 120, downstream zone 140 generally has an axis length L _a shorter than the axial length L _d of the honeycomb body to form a particulate filter 100. For example, in some embodiments, the axial length _{L d} of the downstream zone 140 may be a 50% or more axes length _{L u} of the upstream zone 120. In other embodiments, the downstream zone 140 may be a 67% of the axial length L _a of the honeycomb body to form a particulate filter 100. Generally, the total axial length L _u of the shaft length L _d and the upstream zone 120 of the downstream zone 140 is less axial length L _a of the honeycomb body to form a particulate filter 100.

In one or more embodiments, the upstream zone 120 is free of SCR catalyst. In one or more embodiments, the honeycomb body forming the particulate filter 100 includes an SCR catalyst arranged in and / or on the porous flow path wall portion 106 of the upstream zone 120. In one or more embodiments, the honeycomb body comprises an SCR catalyst located in or on the porous flow path wall of the downstream zone 140. As used herein, the term "inside" of the porous flow path wall means that the SCR catalyst is embedded in the porous wall or permeates the porous wall of the particulate filter. In other words, the SCR catalyst invades the open perforated portion of the flow path wall portion 106. The term "above" the porous wall portion means that the SCR catalyst is arranged on the outer surface of the wall portion and is not embedded in the flow path wall portion 106. In one or more embodiments, the SCR catalyst can be placed both within the channel wall 106 and on the channel wall 106.

In one or more embodiments, the ratio of the axial length _{L a} of the honeycomb body in the axial length _{L u} of the upstream zone 120 _(L u / L _a) is greater than 0 0.75 or less, 0.1 Greater than 0.75 or less, greater than 0.15 and less than 0.75, or greater than 0.15 and less than 0.60. In one or more embodiments, the downstream zone 140 is a local catalyst in the range of about 80 g / L to about 200 g / L, about 100 g / L to about 180 g / L, or about 120 g / L to about 180 g / L. Has a filling amount. In one or more embodiments, the axial length _{L u} of the upstream zone 120 ranges from about 50% to 80% of the _{L a} of _{L a,} downstream zone 140 is from about 100 g / L to about 180g It has a local catalyst charge in the range of / L, from about 100 g / L to about 180 g / L, or from about 120 g / L to about 180 g / L.

In one or more embodiments, the porous flow path wall has a porosity in the range of about 45% to about 75% and a median pore size in the range of 5 micrometers to about 30 micrometers. ..

Another aspect of the present disclosure relates to a lean burn engine exhaust system comprising the particulate filter according to any one of the above embodiments, wherein the lean burn engine exhaust system further comprises a nitrogen reduction located upstream of the particulate filter. Includes agent injection section. The nitrogen reducing agent may include ammonia, urea, ammonium carbamate, and hydrocarbons (eg, diesel fuel). The nitrogen reducing agent injection unit includes a reducing agent storage unit, a pump, a pressure adjusting unit, and a nozzle, and the nitrogen reducing agent can be injected into the exhaust gas stream.

In some embodiments, the SCR catalyst is, but is not limited to, oxides of base metals such as vanadium, tungsten, molybdenum, ceria, zirconia, and mixtures thereof, and / or copper-exchanged or iron-exchanged zeolites. Such as zeolite-based SCR catalyst may be included. In some embodiments, all mixtures of the above substances can be used as SCR catalysts. In one or more embodiments, the SCR catalyst comprises a catalytic material having a lower relative SCR activity than the Cu exchange SSZ-13 zeolite SCR catalyst. The relative SCR activity has the same characteristics (porousness, pore size, volume, wall thickness, etc.), and the SCR activity of various SCR catalysts coated on the particulate filter with the same catalyst filling amount is the same test conditions. It can be specified by evaluating (exhaust gas composition and space velocity). In one or more embodiments, the SCR catalyst is selected from the group consisting of Cu-exchanged SAPO-34 molecular sieves, Cu-exchanged ZSM-5 zeolites, Cu-exchanged beta-zeolites, and Fe-exchanged ZSM-5 zeolites. The present inventor places the SCR catalyst having low relative SCR activity on the particulate filter as in one or more embodiments described herein, so that the particulates are coated along the entire length with the same catalyst filling amount. It has been identified that NO _x removal can be improved compared to filters. The embodiments of the present disclosure allow the use of cheaper SCR catalyst materials than Cu exchange SSZ-13 SCR catalysts.

In one or more embodiments described herein, the SCR catalyst is wash-coated on the flow path wall 106 of the downstream zone 140 and the SCR catalyst is on the flow path wall 106 of the downstream zone 140. In the pores of the flow path wall 106 of the downstream zone 140 (as schematically shown in FIG. 2) or (as schematically shown in FIG. 3) the flow path wall of the downstream zone 140. Both above 106 and inside the pores of the flow path wall portion 106 of the downstream zone 140 are coated. The SCR catalyst can be formed in the downstream zone 140 by a step of first forming a slurry of the SCR catalyst in a liquid solvent such as water. For example, when the SCR catalyst is a copper exchange zeolite, the SCR catalyst is mixed with water to form a slurry. Next, the outlet end 104 of the particulate filter 100 is immersed in the slurry so that the slurry penetrates the particulate filter 100 to a desired depth, which, in one embodiment, is generally the axial length of the downstream zone 140. Corresponds to L _d . More specifically, the slurry enters the outlet flow path 110 and / or the once-through flow path 109 of the particulate filter 100, passes through the flow path wall portion 106, and enters the adjacent inlet flow path 108 with the flow path wall portion. It penetrates through the open pore structure of 106, thereby forming the catalyst into the pores of the flow path wall portion 106. In one embodiment, the vacuum system can be attached to the inlet end 102 of the particulate filter 100 when the particulate filter is immersed in the slurry. The vacuum system pulls the catalyst upward through the flow path wall 106. After removing the particulate filter 100 from the slurry, excess slurry can be discharged from the particulate filter 100. In one embodiment, a compressed fluid such as compressed air can be injected into the particulate filter 100 to help remove the remaining slurry. After that, the particulate filter 100 is dried and calcinated. In the present specification, the catalyst filling amount is expressed in grams / liter after the coated filter is dried and calcinated.

By wash-coating the particulate filter 100 with a catalyst film, the catalyst is formed in the pores when the wash coat is removed and / or dried, so that the pore size and porosity of the flow path wall portion 106 tend to decrease. There is. As a result, the transmittance of the wash-coated flow path wall portion 106 is reduced. In the embodiments described herein, the downstream zone 140 of the particulate filter 100 is wash-coated to achieve the desired transmittance ratio between the upstream zone 120 and the downstream zone 140. In the embodiments described herein, the downstream zone 140 of the particulate filter 100 is wash-coated with a catalyst so that the upstream zone gas permeability ranges from about 5 to about 90 times the downstream zone gas permeability. , About 6 to about 90 times, about 7 to about 90 times, about 8 to about 90 times, about 9 to about 90 times, about 10 to about 90 times, about 15 to about 90 times, about 20 to about 90 times Double, about 25 to about 90 times, about 30 to about 90 times, about 35 to about 90 times, about 40 to about 90 times, about 45 to about 90 times, or about 50 to about 90 times.

When wash-coated in this way, the exhaust gas 200 entering the inlet flow path 108 is the flow path of the particulate filter 100 that removes soot from the exhaust gas in the upstream zone 120 before the exhaust gas is catalytically reacted in the downstream zone 140. It easily passes through the wall portion 106.

Reduction of NO _x compounds in the exhaust stream generally involves reaction with NO _x class reducing agents (ie, CO, H ₂ , HC, or NH ₃ ), producing nitrogen and water. For example, ammonia (NH ₃ ) can be injected into the exhaust gas stream to promote the reduction of NO _x compounds in the exhaust gas stream without the use of a catalyst. The SCR DeNO _x reaction proceeds as shown in the following equation.
NO + NH ₃ + 0.25O ₂ → N ₂ + 1.5H ₂ O a)
NO + NO ₂ + 2NH ₃ → 2N ₂ + 3H ₂ Ob)
0.75NO ₂ + NH ₃ → 0.875N ₂ + 1.5H ₂ Occ)
However, formula a) relates to a standard SCR reaction, formula b) relates to a fast SCR reaction, and formula c) relates to a NO ₂ SCR reaction.

Another aspect of the present disclosure relates to a method for producing a catalytic particulate filter. The method specifies a subject selective catalytic reduction (SCR) catalyst filling mass for a honeycomb body having an inlet end and an outlet end and including a plurality of porous flow path walls extending axially from the inlet end to the outlet end. It includes a step, a step of defining an axis length L _a of the honeycomb body, a plurality of porous flow path wall portion defines a flow path that allows the inlet end the gas to flow to the outlet end, the flow at least a first set of road is closed by at least one near the inlet end or outlet end, the subject SCR catalyst loading is specified based on the axis length L _a of the honeycomb body. The method further includes the steps of immersing the outlet end to the SCR catalyst slurry was coated honeycomb body to axis length L _a shorter length, and a step of providing a honeycomb body was coated, target SCR catalyst loading mass There are to be included in the length of less than 75% of the axial length L _a of the honeycomb body. In one or more embodiments of the method, the coated honeycomb body has an upstream zone axial length and an upstream zone gas permeability and a downstream zone having a downstream zone gas permeability. The porous flow path wall is uncoated in the upstream zone, and the gas permeability of the upstream zone is about 5 to about 90 times, about 6 to about 90 times, and about 7 of the downstream zone gas permeability. About 90 times, about 8 to about 90 times, about 9 to about 90 times, about 10 to about 90 times, about 15 to about 90 times, about 20 to about 90 times, about 25 to about 90 times, from about 30 It ranges from about 90 times, about 35 to about 90 times, about 40 to about 90 times, about 45 to about 90 times, or about 50 to about 90 times.

In one or more embodiments, after immersing the outlet end, the SCR catalyst is placed in the downstream zone from about 50 g / L to about 200 g / L, from about 80 g / L to about 200 g / L, from about 100 g / L. It exists in a filling amount of about 180 g / L, or in the range of about 120 g / L to about 180 g / L. In one or more embodiments, the after immersion of the outlet end, the subject SCR catalyst loading mass is about 30% of the _{L a} 60% of the range of _{L a,} or from about 50% _{L a} of _{L a} Included in lengths in the 80% range. In some embodiments, the after immersion of the outlet end, the upstream zone axis length in the range of about 50% to 80% of L _a of L _a, downstream zone is from about 100 g / L to about It has a local catalyst filling amount in the range of 180 g / L.

One or more embodiments described herein exhibit improved diesel particulate filter SCR performance by zoning and coating the SCR catalyst as described herein. Surprisingly, the same catalytic mass, by applying gradually less coating length, increasing the NO _x conversion, therefore, it was found to improve the catalyst utilization efficiency. This means that without increasing the catalyst, simply by changing the catalyst distribution, to provide an opportunity to increase the NO _x conversion system. Alternatively, even if NO _x conversion system is already enough, by varying the catalyst distribution then it may reduce the catalyst loading. By zoning and coating the catalyst arrangement according to one or more embodiments, as a result, a part of the filter remains uncoated and the coating length is shortened, and the coated wall portion is formed. The transmittance of the material decreases.

In one or more embodiments, the catalytic performance can be enhanced. If a higher NO _x conversion is desired for the same constant amount of washcoat, then the catalyst utilization efficiency can be increased by varying the coating distribution. There can be a cost reduction effect. If the NO _x conversion is already sufficient, then the washcoat filling amount can be reduced as a result of improving the catalyst utilization efficiency by changing the coating distribution. The coated particulate filter can be designed more freely. Typically, the only way to increase catalytic activity is to add a washcoat or provide a highly active catalyst such as Cu exchange SSZ-13, but in one or more embodiments. No such highly active catalyst is required. By varying both the washcoat fill and the coating distribution, three important attributes can be optimized: catalytic conversion, pressure reduction, and filtration efficiency. Since the catalytic efficiency is high when the coating film is divided into zones, the coated particulate filter can be designed more freely. This makes it possible to use the potential catalytic functionality added by utilizing the uncoated portion of the filter. Filtration efficiency typically passes through the minimum efficiency for higher washcoat fills, but by including uncoated parts and washcoated walls with higher fills in the same filter, this minimum filtration efficiency. Can be avoided.

In the set of other embodiments described in the present specification, a method for producing a catalyst fine particle filter is disclosed, in which the outlet end of the honeycomb body including the porous flow path wall portion is put into the SCR catalyst slurry of the honeycomb body. is immersed to a-axis length L _a of less than depth, at least a first shaft portion of the first plurality of walls of the porous channel walls comprising the step of coating the SCR catalyst, the axial length of the honeycomb body providing a coating honeycomb body was coated with the target SCR catalyst filling mass contained 75% or less of the length of L _a, porous channel wall, axially extending from the inlet end to the outlet end.

In some embodiments, SCR catalyst is not present in 25% or more areas extending from 5% of the shaft length L _a of the honeycomb body to 30%.

In some embodiments, the honeycomb body comprises a second shaft portion in which the porous flow path wall portion is not exposed to the SCR catalyst slurry, the second shaft portion having a transmittance of about 7 of the first shaft portion. It has a transmittance in the range of about 90 times.

In some embodiments, the SCR catalyst is present in the first shaft portion with a filling amount in the range of about 50 g / L to about 200 g / L.

In some embodiments, the subject SCR catalyst loading mass comprises from about 30% _{L a} to the first shaft portion of the 60% of the range of _{L a.}

In some embodiments, the subject SCR catalyst loading mass is included in the range of about 50% to 80% of the _{L a} of _{L a.}

In some embodiments, the first shaft portion has a local catalyst charge in the range of about 80 g / L to about 200 g / L.

In some embodiments, the first shaft portion has a local catalyst charge in the range of about 100 g / L to about 180 g / L.

In some embodiments, the first shaft portion has a local catalyst charge in the range of about 120 g / L to about 180 g / L.

In some embodiments, the second shaft portion is in the range from about 50% to 80% of _{L a} of _{L a,} first shaft portion is in the range of from about 100 g / L to about 180 g / L It has a local catalyst filling amount.

In some embodiments, the ratio of the axial length _{L a} of the upstream zone axis honeycomb body length _{L u (L u / L a} ) is greater than 0, is 0.75 or less.

In some embodiments, the ratio of the axial length _{L a} of the upstream zone axis honeycomb body length _{L u (L u / L a} ) is greater than 0.1, 0.75 or less.

In some embodiments, the ratio of the axial length _{L a} of the upstream zone axis honeycomb body length _{L u (L u / L a} ) is greater than 0.15 and less than 0.75.

In some embodiments, the ratio of the axial length _{L a} of the upstream zone axis honeycomb body length _{L u (L u / L a} ) is greater than 0.15 and less than 0.60.

Four samples were prepared with different catalyst distributions on the same particulate filter with a shaft length of 6 inches (about 15.24 cm). The target wash coat filling amount was 75 g / L for all four samples, and the coating length was gradually shortened. In Comparative Example 1 (shown by # 7 in FIG. 4), the wash coat filling was uniformly distributed along the axial length of the filter for a filling amount of 80 g / L. Example 1 (shown in # 5 in FIG. 4) has an uncoated or uncoated 1 inch (about 2.54 cm) upstream zone, with 5 downstream zones containing the SCR catalyst. It was an inch (about 12.7 cm) long. The SCR catalyst filling amount for the filter was 75 g / L. Example 2 (shown in 6A in Table 1) has a filling rate of 77 g / L and the upstream zone is 2 inches (about 5.08 cm) long and is uncoated or uncoated. On the other hand, the downstream zone was coated and was 4 inches (about 10.16 cm) long. Example 3 (shown by # 12A in FIG. 4) has a filling volume of 79 g / L, an uncoated or uncoated 3 inch (about 7.62 cm) upstream zone, and 79 g. It had a downstream zone coated with / L.

All samples were coated with Cu-exchanged SAPO obtained from Zeolist International. The filter was a high-pass filter (HPF) with a cordierite composition. The filter was coated to a certain length through either the outlet channel or the inlet channel using a dipping process. Excess slurry was removed using a vacuum section connected to the filter in the same orientation as the coating. To achieve a partial length coating, lower the filter at an appropriate distance to achieve the desired coating length. The slurry flows through the flow path and further to the filter by wall capillary force and hydrostatic pressure. The immersion depth correlates with the coating length as expected, but it is not a 1: 1 correlation because the slurry is carried to the porous wall by capillary action in front of the liquid front surface of the flow path. To increase the local washcoat fill, the slurry solid fill must be increased. The realization of a filter coated at 180 g / L to 3 inches (about 7.62 cm) is just the limit of the slurry introduction method that can be processed by immersion, because the viscosity increases as the solid filling amount increases. is there. If the solid filling amount increases even a little, the presence of the flow path obstruction that acts as a pool of the aqueous phase leads to cast-in molding at the end face, and then leads to solid film formation at the end face, which leads to flow. Often the path is completely closed from the uptake of the slurry.

Prior to the NO _x SCR test, the filters were dried (100 ° C) and calcinated (550 ° C / 3 hours). Table 1 shows the various samples in more detail. Example 4 (shown as 7A) was coated in the same manner as in Example 1, but in Example 4, it was coated from the inlet end. Example 5 (shown as 9A) was coated in the same manner as in Example 2, but in Example 5, it was coated from the inlet end. Pressure reduction performance due to soot adhesion with 26 scfm (about 73 lL / min) air, at room temperature, commercially available soot Printex U, and 2 inches (about 5.08 cm) in diameter and 6 inches (about 15.24 cm) in length. Evaluated using a wall-thick honeycomb filter at 350 cells (cpsi) (about 54 / cm ² ) per square inch and 12 mils (about 305 micrometers).

For Comparative Examples 1 to 3, the local washcoat filling amount was increased from about 80 to 92, 113, 181 g / L, and the local washcoat filling of the sample coated with 3 inches (about 7.62 cm). The amount is shown to be more than twice that of Comparative Example 1. Attempts were made to achieve a target coating level of 75 g / L for each sample, but it can be seen that few samples exceeded the target level. The last two samples included in this table (Examples 4 and 5) were coated on the opposite side of the samples, and further data were obtained for these samples.

A pressure drop test was performed at 2 inches (about 5.08 cm) in diameter, 6 inches (about 15.24 cm) in length, and 12 mils (about 305) at 350 cells (cpsi) (about 54 / cm ² ) per square inch. The pressure drop of the soot adhesion filter having a honeycomb structure with a wall thickness of (micrometer) was evaluated using a commercially available soot Printex U at 26 scfm (about 73 lL / min) air and room temperature.

FIG. 4 shows the pressure reduction reaction measured as a function of soot adhesion for the fully and partially coated filter and the uncoated filter, which is a control example shown as “uncoated OSV”. In the soot adhesion pressure reduction test, the uncoated (control example) high porosity filter (circular) showed that there were relatively no sharp bends. Next, a filter coated with a length of 5 inches (about 12.7 cm) (Example 1) (diamond) and 6 inches (about 15.24 cm) (Comparative Example 1) (triangle) through the outlet flow path. The decrease in soot adhesion pressure is similar. For both filters, sharp bends are observed with soot around 0.5 g / L. The filter of Example 3 (square) coated through the outlet flow path with a coating length of 3 inches (about 7.62 cm) has the largest soot adhesion pressure drop. The sharp bends observed in other coated samples are not apparent at this coating length. The 4-inch (about 10.16 cm) coated filter (Example 2) used in the catalyst study was unfortunately damaged and pressure drop data could not be obtained. The coating effect is similar for filters coated at 5 inches (about 12.7 cm) and full length, and the pressure drop of filters coated at 3 inches (about 7.62 cm) is clearly one step higher. FIG. 5 shows the pressure drop divided into the selected conditions, that is, no stain (no soot), 2 g / L of soot adhesion, and 4 g / L of soot adhesion.

In FIG. 5, the pressure drop is from no stain (0 g / L soot, dark diagonal bar graph) to 2 g / L soot adhesion (middle gray bar graph), and 4 g / L soot adhesion (white bar graph). ) Is shown to increase to the expected value. The relative changes in the percentage of pressure drop are shown at the top of each bar graph based on the pressure drop of the clean filter.

NO _x reduction tests were evaluated at a spatial velocity of 70,000 / hour, 500 ppm NO _x , 500 ppm NH ₃ , and various temperatures, as shown in the drawings.

FIG. 6 shows the entire (6 inches (about 15.24 cm) length) and partially (3 inches (about 7.62 cm) to 5 inches (about 12.24 cm) length using a laboratory tabletop reactor. The SCR catalyst performance results collected for the HPF filter coated with a length of 7 cm) are shown. Surprisingly, NO _x activity was increased for samples with shorter coating lengths. When all the wash coat filling amounts are in the range of 75 to 80 g / L, the increased conversion indicates that the catalyst utilization efficiency is increased. 6, the overall length of the coating, NO _x conversion filters tested is the lowest, clearly show that it is disadvantageous. Furthermore, contrary to intuition, changing the film distribution filter, as the film length is shortened, shows a higher NO _x conversion. By repeating the measurement on three samples of the four samples at all temperatures, shows a change in 2-3% of the absolute NO _x conversion, it is sufficient to differences between samples reflect differences in performance of the filter It shows that it is large. FIG. 7 more concisely illustrates this trend as a function of film length using the conversion at 250 ° C. obtained from FIG. If the overall washcoat amount is the same and the coating length is shorter, the conversion is expected to decrease through the maximum value, as the washcoat will become so honey-filled that it impedes the movement of gas at some point.

FIG. 8 shows the NO _x transformation as a function of temperature in both the forward and backflow directions for the fully and partially coated filters. The one coated to 4 inches (about 10.16 cm) was damaged, and data in the backflow direction could not be obtained. The results clearly show similar conversions in all cases, especially for partially coated filters, even if the temperature is non-uniform in the axial direction, as described herein. It shows that the advantages of using a coating are not lost. 8, the flow of forward and reverse flow directions of the total and partial filter coated, by comparing the NO _x conversion as a function of temperature, shows that there is no such thing. It is clear that the conversion is not significantly affected by the orientation of the filter in the reactor, and the non-uniformity of heat does not prevent the results shown here, but rather the actual use of catalysts. It shows that it increases efficiency.

The magnitude of the difference in NO _x conversion observed in the present disclosure can be applied to the low activity SCR catalyst by other catalysts such as the original Cu conversion SSZ-13, which already has high catalyst utilization efficiency. The embodiments described herein may provide cost savings in new markets without conventional like _the NO _x reduction. Thus, embodiments are not expensive, robustness is low, while minimizing the cost is a critical factor in new markets, are distributed in the filter so as to meet regulatory and achieve sufficient NO _x conversion An SCR catalyst is provided.

It will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit or scope of this disclosure.

Hereinafter, preferred embodiments of the present invention will be described in terms of terms.

Embodiment 1
In the particulate filter
A honeycomb body having an inlet end and an outlet end,
Including
A plurality said honeycomb body defines a axis length L _a of the honeycomb body from the inlet end extends axially into the outlet end, further, defining a flow path extending in the outlet end from said inlet end Including the porous flow path wall portion of the flow path, at least the first set of the flow paths is closed, and the honeycomb body further has an upstream zone gas permeability and the axial length of the honeycomb body. upstream zone having an L _a shorter upstream zone axis length L _u, and are located close to the outlet end than the upstream side zone comprises a downstream zone having a downstream zone gas permeability,
The plurality of porous flow path walls of the honeycomb body contain a selective catalytic reduction (SCR) catalyst that promotes selective catalytic reduction of NO _x , and the SCR catalyst ranges from about 50 g / L to about 200 g / L. A fine particle filter that is present in the packing of the downstream zone with a local filling amount of the above, and the gas permeability of the upstream zone is in the range of about 5 times to about 90 times the gas permeability of the downstream zone.

Embodiment 2
The particulate filter according to the first embodiment, wherein the upstream zone does not contain an SCR catalyst.

Embodiment 3
The particulate filter according to the first embodiment, wherein the honeycomb body contains an SCR catalyst arranged in or on the porous flow path wall portion of the upstream zone.

Embodiment 4
The particulate filter according to the first embodiment, wherein the honeycomb body contains an SCR catalyst arranged in or on the porous flow path wall portion of the downstream zone.

Embodiment 5
The particulate filter according to the first embodiment, wherein the first set of the flow paths is closed at a position close to at least one of the inlet end and the outlet end.

Embodiment 6
The ratio of the axial length _{L a} of the upstream zone axis, wherein the honeycomb body length _{L u (L u / L a} ) is greater than 0, is 0.75 or less, particulate filter according to the first embodiment.

Embodiment 7
The ratio with respect to the axial length _{L a} of the honeycomb body of the upstream zone axis length _{L u (L u / L a} ) is greater than 0.1, 0.75 or less, fine particles of embodiment 1 filter.

8th Embodiment
The ratio with respect to the axial length _{L a} of the honeycomb body of the upstream zone axis length _{L u (L u / L a} ) is greater than 0.15, 0.75 or less, the particulate filter according to Embodiment 1 ..

Embodiment 9
The ratio with respect to the axial length _{L a} of the honeycomb body of the upstream zone axis length _{L u (L u / L a} ) is greater than 0.15, less than 0.60, particles of embodiment 1 filter.

Embodiment 10
The particulate filter according to the first embodiment, wherein the downstream zone has a local catalyst filling amount in the range of about 80 g / L to about 200 g / L.

Embodiment 11
The particulate filter according to the first embodiment, wherein the downstream zone has a local catalyst filling amount in the range of about 100 g / L to about 180 g / L.

Embodiment 12
The particulate filter according to the first embodiment, wherein the downstream zone has a local catalyst filling amount in the range of about 120 g / L to about 180 g / L.

Embodiment 13
It said upstream zone axis length _{L u} ranges from about 50% to 80% of the _{L a} of _{L a,} the downstream zone, local catalyst loading in the range of from about 100 g / L to about 180 g / L The particulate filter according to the first embodiment.

Embodiment 14
In the first embodiment, the porous flow path wall portion has a porosity in the range of about 45% to about 75% and a median pore size in the range of 5 micrometers to about 30 micrometers. The particulate filter described.

Embodiment 15
In the lean burn engine exhaust system
The particulate filter according to any one of embodiments 1 to 14,
A system including a nitrogen reducing agent injection portion arranged on the upstream side of the particulate filter.

Embodiment 16
In the method for manufacturing a particulate filter with a catalyst
Inlet end and an outlet end, the plurality of porous flow path wall portion honeycomb body comprising defining an axial length L _a of the honeycomb body to extend in the axial direction to said exit end of said inlet end, object selection catalytic reduction of (SCR) catalyst loading mass, a step of identifying, based on the axial length L _a of the honeycomb body, wherein the plurality of porous flow path wall, the gas into the outlet end of the inlet end A step of defining a flow path that enables the flow of the flow path, and at least the first set of the flow paths is closed.
Said outlet end is immersed in the SCR catalyst slurry, the honeycomb body was coated until the shaft length L _a length shorter than, the target SCR catalyst charge mass of the shaft length L _a of the honeycomb body 75 A method comprising a step of providing a honeycomb body coated so as to be contained in less than%.

Embodiment 17
The coated honeycomb body includes an upstream zone having an upstream zone axial length and an upstream zone gas permeability, and a downstream zone having a downstream zone gas permeability, and the porous flow path wall portion is The method according to embodiment 16, wherein the upstream zone is uncoated and the upstream zone gas permeability is in the range of about 7 to about 90 times the downstream zone gas permeability.

Embodiment 18
16. The method of embodiment 16, wherein the SCR catalyst is present in the downstream zone with a filling amount in the range of about 50 g / L to about 200 g / L after the outlet end is immersed.

Embodiment 19
After immersed the outlet end, the subject SCR catalyst charge mass are intended to be within the range of from about 30% to 60% of the L _a of L _a, method of embodiment 16.

20th embodiment
After immersed the outlet end, the subject SCR catalyst charge mass are intended to be within the range of about 50% to 80% of the L _a of L _a, method of embodiment 16.

21st embodiment
16. The method of embodiment 16, wherein the downstream zone has a local catalyst filling amount in the range of about 80 g / L to about 200 g / L after the outlet end is immersed.
The method described in.

Embodiment 22
16. The method of embodiment 16, wherein the downstream zone has a local catalyst filling amount in the range of about 100 g / L to about 180 g / L after the outlet end is immersed.

23rd Embodiment
16. The method of embodiment 16, wherein the downstream zone has a local catalyst filling amount in the range of about 120 g / L to about 180 g / L after the outlet end is immersed.

Embodiment 24
After immersed the outlet end, said upstream zone axis length ranges from about 50% to 80% of the _{L a} of _{L a,} the downstream zone is from about 100 g / L to about 180 g / L The method according to embodiment 17, wherein the local catalyst filling amount is in the range of.

25.
16. The method of embodiment 16, wherein the first set of channels is closed near at least one of the inlet end or the outlet end.

Embodiment 26
In the method for manufacturing a catalytic particulate filter
The outlet end of the honeycomb body comprising a porous channel walls extending in the axial direction at the outlet end from the inlet end, the SCR catalyst slurry, by dipping to the shaft length L _a of less than the depth of the honeycomb body, wherein the porous at least a first shaft portion of the first plurality of walls sexual channel wall and coated with an SCR catalyst, the target SCR catalyst filling mass contained in more than 75% of the axial length L _a of the honeycomb body The step of providing the coated honeycomb body,
How to include.

Embodiment 27
The SCR catalysts are those that are not present in 25% or more regions extending in the 5% to 30% of the axial length L _a of the honeycomb body, the method of embodiment 26.

28.
The honeycomb body includes a second shaft portion, the porous flow path wall portion is not exposed to the SCR catalyst slurry, and the second shaft portion is about 7 to about 90 of the first shaft portion. The method according to embodiment 26, which has a transmittance in a double range.

Embodiment 29
The method according to embodiment 26, wherein the SCR catalyst is present in the first shaft portion with a filling amount in the range of about 50 g / L to about 200 g / L.

30th embodiment
The target SCR catalyst charge mass are intended to be included about 30% of the L _a to the first shaft portion of the 60% of the range of L _a, method of embodiment 26.

Embodiment 31
The target SCR catalyst charge mass is intended to be within the range of about 50% to 80% of the _{L a} of _{L a,} method of embodiment 26.

Embodiment 32
26. The method of embodiment 26, wherein the first shaft portion has a local catalyst filling amount in the range of about 80 g / L to about 200 g / L.

Embodiment 33
26. The method of embodiment 26, wherein the first shaft portion has a local catalyst filling in the range of about 100 g / L to about 180 g / L.

Embodiment 34
26. The method of embodiment 26, wherein the first shaft portion has a local catalyst filling in the range of about 120 g / L to about 180 g / L.

Embodiment 35
It said second shaft portion is in the range from about 50% to 80% of _{L a} of _{L a,} the first shaft portion, a local catalyst loading in the range of from about 100 g / L to about 180 g / L 28. The method of embodiment 28, which has.

Embodiment 36
The ratio with respect to the axial length _{L a} of the honeycomb body of the upstream zone axis length _{L u (L u / L a} ) is greater than 0, is 0.75 or less, The method of embodiment 26.

Embodiment 37
The ratio with respect to the axial length _{L a} of the honeycomb body of the upstream zone axis length _{L u (L u / L a} ) is greater than 0.1, 0.75 or less, The method of embodiment 26 ..

38.
The ratio with respect to the axial length _{L a} of the honeycomb body of the upstream zone axis length _{L u (L u / L a} ) is greater than 0.15, 0.75 or less, The method of embodiment 26 ..

Embodiment 39
The ratio of the axial length _{L a} of the upstream zone axis, wherein the honeycomb body length _{L u (L u / L a} ) is less than greater than 0.15 0.60 The method of embodiment 26.

100 Fine particle filter 101 Flow path 102 Inlet end 104 Outlet end 105 Outer skin layer 106 Flow path wall part 108 Inlet flow path 109 Through flow flow path 110 Outlet flow path 112 Blocked part

Claims (5)

In the particulate filter
A honeycomb body having an inlet end and an outlet end,
Including
A plurality said honeycomb body defines a axis length L _a of the honeycomb body from the inlet end extends axially into the outlet end, further, defining a flow path extending in the outlet end from said inlet end Including the porous flow path wall portion of the flow path, at least the first set of the flow paths is closed, and the honeycomb body further has an upstream zone gas permeability and the axial length of the honeycomb body. upstream zone having an L _a shorter upstream zone axis length L _u, and are located close to the outlet end than the upstream side zone comprises a downstream zone having a downstream zone gas permeability,
The plurality of porous flow path walls of the honeycomb body contain a selective catalytic reduction (SCR) catalyst that promotes selective catalytic reduction of NO _x , and the SCR catalyst ranges from about 50 g / L to about 200 g / L. A fine particle filter that is present in the packing of the downstream zone with a local filling amount of, and the gas permeability of the upstream zone is in the range of about 5 to about 90 times the gas permeability of the downstream zone. The particulate filter according to claim 1, wherein the upstream zone does not contain an SCR catalyst. The particulate filter according to claim 1, wherein the honeycomb body contains an SCR catalyst arranged in or on the porous flow path wall portion of the upstream zone. The particulate filter according to claim 1, wherein the first set of the flow paths is closed at a position close to at least one of the inlet end and the outlet end. In the method for manufacturing a particulate filter with a catalyst
Inlet end and an outlet end, the plurality of porous flow path wall portion honeycomb body comprising defining an axial length L _a of the honeycomb body to extend in the axial direction to said exit end of said inlet end, object selection catalytic reduction of (SCR) catalyst loading mass, a step of identifying, based on the axial length L _a of the honeycomb body, wherein the plurality of porous flow path wall, the gas into the outlet end of the inlet end A step of defining a flow path that enables the flow of the flow path, and at least the first set of the flow paths is closed.
Said outlet end is immersed in the SCR catalyst slurry, the honeycomb body was coated until the shaft length L _a length shorter than, the target SCR catalyst charge mass of the shaft length L _a of the honeycomb body 75 A method comprising a step of providing a honeycomb body coated so as to be contained in less than%.

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