CN117716118A

CN117716118A - Exhaust gas treatment method and apparatus with particulate filter and SCR

Info

Publication number: CN117716118A
Application number: CN202280035639.6A
Authority: CN
Inventors: D·M·比尔; S·乔治; M·戈文达雷迪; A·K-E·赫贝尔
Original assignee: Corning Inc
Current assignee: Corning Inc
Priority date: 2021-04-05
Filing date: 2022-04-05
Publication date: 2024-03-15

Abstract

An exhaust gas treatment method and apparatus for treating an exhaust gas stream flowing in a downstream direction through an exhaust gas line housing, the apparatus comprising a first particulate filter, an SCR unit and a second particulate filter downstream of the SCR unit, all arranged in series in the exhaust gas line.

Description

Exhaust gas treatment method and apparatus with particulate filter and SCR

Cross Reference to Related Applications

The present application claims priority from U.S. c. ≡119 to U.S. provisional application sequence No. 63/315334 filed on 3/1 of 2022, U.S. provisional application sequence No. 63/29573 filed on 12/20 of 2021, U.S. provisional application sequence No. 63/171454 filed on 6 of 2021, and U.S. provisional application sequence No. 63/170823 filed on 5 of 2021, the contents of which are hereby incorporated herein by reference in their entirety.

Technical Field

Embodiments of the present disclosure relate generally to engine exhaust treatment and, in particular, to exhaust treatment apparatus and methods including particulate filtration and SCR treatment.

Background

A particulate filter, such as a Diesel Particulate Filter (DPF), filters particulates from an exhaust stream of an engine, such as an engine that burns diesel fuel. Many exhaust treatment systems use Selective Catalytic Reduction (SCR) assemblies that utilize injection of a reductant such as ammonia or urea.

Disclosure of Invention

In one aspect, an exhaust treatment device disclosed herein for treating an exhaust stream flowing in a downstream direction through an exhaust line housing (exhaust line housing) from an upstream location to a downstream location of the exhaust line housing, the exhaust treatment device comprising: an upstream assembly comprising one or more urea injector/mixing assemblies including a last urea injector/mixing assembly; and a particulate filter disposed downstream of the last urea injector/mixing assembly. That is, one or more particulate filters are disposed downstream of the downstream-most location of the urea injector/mixing assembly (i.e., downstream-most urea injector/mixing assembly). In an embodiment, the upstream assembly further comprises: one or more Diesel Oxidation Catalyst (DOC) assemblies, one or more mixing conduit assemblies, one or more Ammonia Slip Catalyst (ASC) assemblies, and/or one or more electrically heatable assemblies (which comprise one or more heater assemblies and/or one or more Electrically Heatable Catalyst (EHC) assemblies). In an embodiment, at least one of the upstream components is configured for close-coupled mounting (close-coupled mounting).

In another aspect, an exhaust gas treatment device disclosed herein for treating an exhaust gas stream flowing in a downstream direction through an exhaust gas line housing (exhaust line housing) from an upstream location to a downstream location of the exhaust gas line housing, the exhaust gas treatment device comprising: an upstream component comprising at least one particulate filter and one or more SCR units; and a final particulate filter disposed downstream of the upstream assembly. That is, the final particulate filter is disposed downstream of the downstream-most location of the upstream assembly. The particulate filter downstream of the downstream-most location of the upstream component may be an uncatalyzed particulate filter (e.g., without the addition of catalyst material), or the particulate filter may be catalyzed, i.e., coated with an SCR-functional catalyst material, an ammoxidation-functional material, or both. In an embodiment, the upstream assembly further comprises: one or more Diesel Oxidation Catalyst (DOC) assemblies, one or more urea injector assemblies, one or more mixing conduit assemblies, one or more Ammonia Slip Catalyst (ASC) assemblies, and/or one or more electrically heatable assemblies (which include one or more heater assemblies and/or one or more Electrically Heatable Catalyst (EHC) assemblies). In an embodiment, at least one of the upstream components is configured for mounting proximate to the connection.

As used herein, an SCR assembly may include an SCR/ASC (ammonia slip catalyst or ammonia oxidation catalyst) assembly, where the function of the ASC is ammonia oxidation, and in some embodiments where the particulate filter is downstream of the most downstream location of the upstream assembly, it may be uncatalyzed or may be coated with an SCR-functional substance, an ammonia oxidation-functional substance, or both.

In another aspect, an exhaust gas treatment device disclosed herein for treating an exhaust gas stream flowing in a downstream direction through an exhaust gas line housing (exhaust line housing) from an upstream location to a downstream location of the exhaust gas line housing, the exhaust gas treatment device comprising: a first particulate filter; an SCR unit disposed downstream of the first particulate filter; and a second particulate filter disposed downstream of the SCR unit; wherein the first particulate filter, the SCR unit and the second particulate filter are arranged in series in the exhaust gas line housing and configured to allow the exhaust gas stream to flow in series through the first particulate filter, then through the SCR unit, and then through the second particulate filter. The SCR unit may include a reductant doser configured to inject reductant into the exhaust gas in the exhaust line housing downstream of the first particulate filter. In an embodiment, the SCR unit further comprises a selective catalytic reduction catalyst.

The first particulate filter may include a first honeycomb body comprising intersecting porous ceramic walls comprising a first bulk average porosity (measured by mercury porosimetry); and the second particulate filter comprises a second honeycomb body comprising intersecting porous ceramic walls comprising a second bulk average porosity (measured by mercury porosimetry), wherein the second honeycomb body comprises a second bulk median pore diameter that is less than the first bulk median pore diameter of the first honeycomb body.

The first particulate filter may include a first honeycomb body comprising intersecting porous ceramic walls comprising 40-65% of a first bulk average porosity (measured by mercury porosimetry); and the second particulate filter comprises a second honeycomb body comprising intersecting porous ceramic walls comprising 35-55% of a second bulk average porosity (measured by mercury porosimetry).

The first bulk average porosity is microns. The second honeycomb body may comprise a second bulk median pore diameter that is less than the first bulk median pore diameter of the first honeycomb body.

In an embodiment, a first particulate filter comprises a first honeycomb body comprising intersecting porous ceramic walls comprising a first bulk median pore diameter (measured by mercury porosimetry) of 12-30 microns; and the second particulate filter comprises a second honeycomb body comprising intersecting porous ceramic walls comprising a second bulk median pore diameter (measured by mercury porosimetry) of 2-12 microns, and wherein the second bulk median pore diameter is less than the first bulk median pore diameter.

In an embodiment, the first particulate filter comprises a honeycomb body comprising intersecting porous ceramic walls comprising a bulk average porosity (measured by mercury porosimetry) of 40-65%. In an embodiment, the porous ceramic wall comprises a bulk average porosity (measured by mercury porosimetry) of 42-55%. In an embodiment, the porous ceramic wall comprises a bulk median pore diameter (measured by mercury porosimetry) of 5 to 15 μm. In an embodiment, the porous ceramic wall comprises a bulk median pore diameter (measured by mercury porosimetry) of 7 to 12 μm.

In an embodiment, a first particulate filter includes a first honeycomb body comprising intersecting porous ceramic walls comprising a first bulk average porosity (measured by mercury porosimetry); and the second particulate filter comprises a second honeycomb body comprising intersecting porous ceramic walls comprising a second bulk average porosity (measured by mercury porosimetry) and the second bulk average porosity is greater than the first bulk average porosity.

In an embodiment, the first particulate filter comprises a first honeycomb body comprising intersecting porous ceramic walls defining axial channels, wherein the first honeycomb body further comprises plugs selectively disposed in at least some of the axial channels to further define inlet and outlet channels and to provide a plurality of gas flow paths through selected porous ceramic walls. In an embodiment, at least some of the inlet channels have a cross-sectional channel open area that is greater than a cross-sectional channel open area of at least some of the outlet channels. In embodiments, the second may be 48-62%. The first bulk average porosity may be 50-55%. The second bulk average porosity may be 40-55%. The second honeycomb may comprise a second bulk median pore diameter of 5-12 microns. The second honeycomb may comprise a second bulk median pore diameter of 6-12.

The particulate filter includes a second honeycomb body comprising intersecting porous ceramic walls defining axial channels, wherein the second honeycomb body further includes plugs selectively disposed in at least some of the axial channels to further define inlet and outlet channels and to provide a plurality of gas flow paths through selected porous ceramic walls. In an embodiment, a majority of the inlet channels and a majority of the outlet channels in the second particulate filter have substantially the same cross-sectional channel open area.

In another aspect, disclosed herein is a method of treating an exhaust stream, the method comprising: flowing the exhaust stream through a first particulate filter; then, flowing the exhaust stream through the SCR unit after flowing through the first particulate filter; the exhaust stream is then caused to flow through a second particulate filter after exposure to the selective catalytic reduction catalyst.

In an embodiment, in the SCR unit, the exhaust gas stream is mixed with a reducing agent, and the mixture of the exhaust gas stream and the reducing agent flows through a selective catalytic reduction catalyst. In an embodiment, the exhaust stream flows through the second particulate filter after exposure to the selective catalytic reduction catalyst. In an embodiment, the exhaust gas stream is exposed to an oxidation catalyst prior to entering the first particulate filter.

In an embodiment, the oxidation catalyst is a diesel oxidation catalyst. In an embodiment, the exhaust stream entering the first particulate filter comprises exhaust gas and particulates. In embodiments, the exhaust stream entering the first particulate filter comprises soot particles. In an embodiment, the exhaust stream entering the second particulate filter comprises particulates generated by the SCR unit.

In an embodiment, at least some of the particulates from the exhaust stream are removed by the first particulate filter. In embodiments, at least some of the soot particles from the exhaust stream are removed by the first particulate filter. In embodiments, more than 80% of the soot particles entering the first particulate filter are removed by the first particulate filter. In embodiments, at least some of the soot particles that enter the second particulate filter are removed by the second particulate filter. In an embodiment, the flowing through the second particulate filter removes at least some particulates from the exhaust stream. In an embodiment, the exhaust stream entering the second particulate filter comprises particulates generated by the SCR unit. In an embodiment, the flow through the second particulate filter removes at least some of the particulates generated by the SCR unit entering the second particulate filter.

In an embodiment, the flow through the second particulate filter removes at least some of the particulates generated by the SCR unit entering the second particulate filter. In an embodiment, exposing the exhaust stream with the reductant to the selective catalytic reduction catalyst adds SCR-produced particulates to the exhaust stream. In an embodiment, the SCR-produced particles comprise SCR reaction byproduct particles. In an embodiment, the second particulate filter is configured to remove at least some SCR reaction byproduct particles.

In another aspect, disclosed herein is a method of treating an exhaust stream comprising an exhaust gas and particulates, the method comprising: flowing the exhaust stream through a first particulate filter configured to remove at least some particulates from the exhaust stream; then flowing the exhaust gas stream through the SCR unit, wherein a reducing agent is introduced into the exhaust gas stream; the exhaust stream is then caused to flow through a second particulate filter configured to remove at least some particulates from the exhaust stream.

In another aspect, disclosed herein is a method of treating an exhaust stream comprising an exhaust gas and particulates, the method comprising: flowing the exhaust stream through a first particulate filter configured to remove at least some particulates from the exhaust stream; then flowing the exhaust stream through the SCR unit, wherein a reducing agent is introduced into the exhaust gas stream to induce a selective catalytic reaction in the exhaust stream; the exhaust stream is then caused to flow through a second particulate filter configured to remove at least some particulates from the exhaust stream.

In an embodiment, the selective catalytic reaction adds SCR-produced particulates to the exhaust stream, and the second particulate filter is configured to remove at least some SCR-produced particulates. In an embodiment, the particles entering the first particulate filter are mainly soot particles. In an embodiment, the selective catalytic reaction adds SCR-produced particulates to the exhaust stream, and the second particulate filter is configured to remove at least some SCR-produced particulates. In an embodiment, the SCR-produced particles include NH ₃ And (3) base particles.

In an embodiment, the method further comprises regenerating the first particulate filter while the exhaust stream flows through the second particulate filter. In an embodiment, the first particulate filter has an internal temperature of greater than 550 ℃ during regeneration.

Other embodiments of the present disclosure are disclosed herein.

Drawings

So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this disclosure and are therefore not to be considered limiting of its scope, for the disclosure may admit to other equally effective embodiments.

Fig. 1 schematically shows an apparatus or subassembly or exhaust system comprising an exhaust gas line comprising: a first particulate filter + SCR unit + second particulate filter construction, such as a DPF + SCR unit + DPF construction, wherein the SCR unit includes an injector disposed upstream of the substrate, providing selective catalytic reduction catalyst material (SCR) with optional plumbing disposed in the exhaust gas line between the SCR and the second particulate filter.

Fig. 2 schematically shows an apparatus or subassembly or exhaust system comprising an exhaust gas line comprising: an oxidation catalyst + a first particulate filter + an SCR unit + a second particulate filter construction, such as a DOC + a DPF + an SCR unit + a DPF construction, wherein the DOC is a diesel oxidation catalyst, the SCR unit comprising an injector arranged upstream of the substrate, a selective catalytic reduction catalyst material (SCR) being provided with an optional conduit arranged in the exhaust gas line between the SCR and the second particulate filter.

Fig. 3 lists various exhaust treatment devices tested with a heavy duty diesel engine.

Fig. 4 schematically shows output particle count measurements based on the european VI system with a heavy duty diesel engine for five world-coordinated transient cycle (WHTC) tests using a 23nm Solid Particle Count System (SPCS) for the various devices of fig. 3.

Fig. 5 schematically shows system output particle count measurements with a heavy duty diesel engine for five world coordination transient cycle (WHTC) tests using a 10nm Solid Particle Count System (SPCS) for the various devices of fig. 3.

Fig. 6 schematically shows an embodiment of an exhaust gas line comprising: a DOC, a mixer with reductant injection, an SCR, a conduit, a second DOC, a DPF, a second mixer with reductant injection, a second SCR, a conduit, and a second DPF connected in fluid communication such that an exhaust gas stream may flow into an exhaust gas line and move in a downstream direction through the exhaust gas line assembly in series.

Fig. 7 schematically shows an embodiment of an exhaust gas line comprising: a mixer with reductant injection, an SCR, a conduit, a DOC, a DPF, a second mixer with reductant injection, a second SCR, a conduit, and a second DPF connected in fluid communication such that an exhaust gas stream can flow into an exhaust gas line and move in a downstream direction through the exhaust gas line assembly in series.

Fig. 8 schematically shows an embodiment of an exhaust gas line comprising: a mixer with reductant injection, an SCR, a conduit, a DPF integrated with a DOC, a second mixer with reductant injection, a second SCR, a conduit, and a second DPF connected in fluid communication such that an exhaust gas stream can flow into an exhaust gas line and move in a downstream direction through the exhaust gas line assembly in series.

Fig. 9 schematically shows an embodiment of an exhaust gas line comprising: a DOC, a mixer with reductant injection, an SCR, a conduit, a DPF integrated with the DOC, a second mixer with reductant injection, a second SCR, a conduit, and a second DPF connected in fluid communication such that an exhaust gas stream can flow into an exhaust gas line and move in a downstream direction through the exhaust gas line assembly in series.

Fig. 10 schematically shows an embodiment of an exhaust gas line comprising: a DOC-integrated DPF having a mixer for reductant injection, an SCR, a conduit, and a second DPF connected in fluid communication such that an exhaust gas stream can flow into an exhaust gas line and move in a downstream direction through the exhaust gas line assembly in series.

Fig. 11 schematically shows an embodiment of an exhaust gas line comprising: a DOC, a DPF, a mixer with reductant injection, an SCR-integrated DPF, a pipe, and an SCR, which are connected in fluid communication such that an exhaust gas stream can flow into an exhaust gas line and move in a downstream direction through the exhaust gas line assembly in a serial fashion.

Fig. 12 schematically shows an embodiment of an exhaust gas line comprising: a mixer with reductant injection, an SCR, a conduit, a DOC, a DPF, a second mixer with reductant injection, an SCR-integrated DPF, a conduit, and a second DPF connected in fluid communication such that an exhaust gas stream can flow into an exhaust gas line and move in a downstream direction through the exhaust gas line assembly in a serial fashion.

Fig. 13 schematically shows an embodiment of an exhaust gas line comprising: a mixer with reductant injection, an SCR, a conduit, a DOC-integrated DPF, a second mixer with reductant injection, an SCR-integrated DPF, a conduit, and a second DPF connected in fluid communication such that an exhaust gas stream can flow into an exhaust gas line and move in a downstream direction through the exhaust gas line assembly in series.

Fig. 14 schematically shows an embodiment of an exhaust gas line comprising: a DOC-integrated DPF having a mixer for reductant injection, an SCR-integrated DPF, a conduit, and an SCR connected in fluid communication such that an exhaust gas stream can flow into an exhaust gas line and move in a downstream direction through the exhaust gas line assembly in series.

Fig. 15 schematically shows an embodiment of an exhaust gas line comprising: a DOC, a mixer with reductant injection, an SCR, a conduit, a second DOC, a DPF, a second mixer with reductant injection, a second SCR, a third SCR, an ASC, a conduit, and a second DPF connected in fluid communication such that an exhaust gas stream may flow into an exhaust gas line and move in a downstream direction through the exhaust gas line assembly in series.

Detailed Description

Before describing several exemplary embodiments of the disclosure, it is to be understood that the disclosure is not limited to the details of construction or process steps set forth in the following description. The disclosure is capable of other embodiments or of being practiced or carried out in various ways.

For exhaust treatment systems using Selective Catalytic Reduction (SCR) components that employ injection of a reducing agent, such as ammonia or urea, under non-ideal conditions there is a possibility that the reducing agent or byproducts thereof or byproducts of the SCR reaction may generate additional particulates ("SCR particulates") that are added to the exhaust stream and contribute to the particulate emissions exiting the exhaust pipe. The exhaust system may include an exhaust line containing a doc+dpf+scr architecture, an injector and mixer system located to deliver a reductant (such as ammonia or urea or a mixture of ammonia or urea (e.g., diesel exhaust fluid ("DEF") or "AdBlue) ^TM Aqueous solutions of 32.5% urea and 67.5% di water).

In one aspect, an exhaust treatment device disclosed herein for treating an exhaust stream flowing in a downstream direction through an exhaust line housing (exhaust line housing) from an upstream location to a downstream location of the exhaust line housing, the exhaust treatment device comprising: a first particulate filter; an SCR unit disposed downstream of the first particulate filter; and a second particulate filter disposed downstream of the SCR unit; wherein the first particulate filter, the SCR unit and the second particulate filter are arranged in series in the exhaust gas line housing and configured to allow the exhaust gas stream to flow in series through the first particulate filter, then through the SCR unit, and then through the second particulate filter. The SCR unit may include a reductant doser configured to inject a reductant into the exhaust gas in the exhaust line housing downstream of the first particulate filter, and the SCR unit may further include a selective catalytic reduction catalyst.

In some embodiments, the first particulate filter comprises a first honeycomb body comprising intersecting porous ceramic walls comprising a first bulk average porosity (measured by mercury porosimetry); and the second particulate filter comprises a second honeycomb body comprising intersecting porous ceramic walls comprising a second bulk average porosity (measured by mercury porosimetry), wherein the second honeycomb body comprises a second bulk median pore diameter that is less than the first bulk median pore diameter of the first honeycomb body.

In some embodiments, the first particulate filter comprises a first honeycomb body comprising intersecting porous ceramic walls comprising 40-65% of a first bulk average porosity (measured by mercury porosimetry); and the second particulate filter comprises a second honeycomb body comprising intersecting porous ceramic walls comprising 35-55% of a second bulk average porosity (measured by mercury porosimetry).

In some of these embodiments, the first bulk average porosity is 48-62%.

In some of these embodiments, the first bulk average porosity is 50-55%. In some of these embodiments, the second bulk average porosity is 40-55%.

In some embodiments, the second honeycomb comprises a second bulk median pore diameter of 5-22 microns; in some of these embodiments, the second honeycomb comprises a second bulk median pore diameter of 5-12 microns.

In some embodiments, the second honeycomb comprises a second bulk median pore diameter of 6-22 microns; in some of these embodiments, the second honeycomb comprises a second bulk median pore diameter of 6-12 microns.

In some embodiments, the second honeycomb comprises a second bulk median pore diameter that is less than the first bulk median pore diameter of the first honeycomb.

In some embodiments, the first particulate filter comprises a first honeycomb body comprising intersecting porous ceramic walls comprising a first bulk median pore diameter (measured by mercury porosimetry) of 12-30 microns; and the second particulate filter comprises a second honeycomb body comprising intersecting porous ceramic walls comprising a second bulk median pore diameter (measured by mercury porosimetry) of 2-22 microns, and wherein the second bulk median pore diameter is less than the first bulk median pore diameter; in some of these embodiments, the second honeycomb comprises a second bulk median pore diameter of 2-12 microns.

In some embodiments, the first particulate filter comprises a honeycomb body comprising intersecting porous ceramic walls comprising 40-65% of a bulk average porosity (measured by mercury porosimetry).

In some of these embodiments, the porous ceramic wall comprises a bulk average porosity (measured by mercury porosimetry) of 42-55%.

In some of these embodiments, the porous ceramic wall comprises a bulk median pore diameter (measured by mercury porosimetry) of 5 to 15 μm.

In some of these embodiments, the porous ceramic wall comprises a bulk median pore diameter (measured by mercury porosimetry) of 7 to 12 μm.

In some embodiments, the first particulate filter comprises a first honeycomb body comprising intersecting porous ceramic walls comprising a first bulk average porosity (measured by mercury porosimetry); and the second particulate filter comprises a second honeycomb body comprising intersecting porous ceramic walls comprising a second bulk average porosity (measured by mercury porosimetry) and the second bulk average porosity is greater than the first bulk average porosity.

In some embodiments, the first particulate filter comprises a first honeycomb body comprising intersecting porous ceramic walls defining axial channels, wherein the first honeycomb body further comprises plugs selectively disposed in at least some of the axial channels to further define inlet and outlet channels and to provide a plurality of gas flow paths through selected porous ceramic walls.

In some of these embodiments, at least some of the inlet channels have a cross-sectional channel open area that is greater than a cross-sectional channel open area of at least some of the outlet channels.

In some of these embodiments, the second particulate filter comprises a second honeycomb body comprising intersecting porous ceramic walls defining axial channels, wherein the second honeycomb body further comprises plugs selectively disposed in at least some of the axial channels to further define inlet and outlet channels and to provide a plurality of gas flow paths through selected porous ceramic walls; in some of these embodiments, a majority of the inlet channels and a majority of the outlet channels in the second particulate filter have substantially the same cross-sectional channel open area.

In another aspect, disclosed herein is a method of treating an exhaust stream, the method comprising: flowing the exhaust stream through a first particulate filter; then, flowing the exhaust stream through the SCR unit after flowing through the first particulate filter; the exhaust stream is then caused to flow through a second particulate filter after exposure to the SCR unit.

In some embodiments, in the SCR unit, the exhaust stream is mixed with a reductant, and the mixture of the exhaust stream and the reductant flows through a selective catalytic reduction catalyst.

In some embodiments, the exhaust stream flows through a second particulate filter after exposure to the selective catalytic reduction catalyst.

In some embodiments, the exhaust stream is exposed to an oxidation catalyst prior to entering the first particulate filter; in some of these embodiments, the oxidation catalyst is a diesel oxidation catalyst.

In some embodiments, the exhaust stream entering the first particulate filter comprises exhaust gas and particulates.

In some of these embodiments, the exhaust stream entering the first particulate filter comprises soot particles.

In some of these embodiments, the exhaust stream entering the second particulate filter comprises particulates generated by the SCR unit.

In some of these embodiments, at least some of the particulates from the exhaust stream are removed by the first particulate filter.

In some of these embodiments, at least some of the soot particles are removed from the exhaust gas stream by a first particulate filter; in some of these embodiments, more than 80% of the soot particles entering the first particulate filter are removed by the first particulate filter; in some of these embodiments, at least some of the soot particles that enter the second particulate filter are removed by the second particulate filter.

In some of these embodiments, flowing through the second particulate filter causes at least some particulates to be removed from the exhaust stream.

In some of these embodiments, the exhaust stream entering the second particulate filter comprises particulates generated by the SCR unit; in some of these embodiments, the flow through the second particulate filter removes at least some of the particulates generated by the SCR unit entering the second particulate filter; in some of these embodiments, the flow through the second particulate filter removes at least some of the particulates generated by the SCR unit entering the second particulate filter.

In some embodiments, exposing the exhaust stream with the reductant to a selective catalytic reduction catalyst increases SCR-produced particulates to the exhaust stream; in some of these embodiments, the SCR-produced particles comprise SCR reaction byproduct particles; in some of these embodiments, the second particulate filter is configured to remove at least some SCR reaction byproduct particles.

In some embodiments, the selective catalytic reaction adds SCR-produced particulates to the exhaust stream, and the second particulate filter is configured to remove at least some SCR-produced particulates.

In certain embodiments, the particles entering the first particulate filter are primarily soot particles.

In some embodiments, the selective catalytic reaction adds SCR-produced particulates to the exhaust gas stream, and the second particulate filter is configured to remove at least some of the SCR-produced particulates; in some of these embodiments, the SCR-produced particles comprise NH ₃ And (3) base particles.

In some embodiments, the method further comprises regenerating the first particulate filter while the exhaust stream flows through the second particulate filter.

In some embodiments, the first particulate filter has an internal temperature of greater than 550 ℃ during regeneration.

In some embodiments, the method further comprises not regenerating the second particulate filter prior to regenerating the first particulate filter.

In some embodiments, the method further comprises not regenerating the second particulate filter prior to the first particulate filter replacement or ash cleaning.

In some embodiments, the reductant injection portion is connected to the SCR unit; and in some of these embodiments, a reductant doser is disposed upstream of the SCR unit; in other of these embodiments, the reductant doser is integrated into the SCR unit.

In some embodiments, the reducing agent comprises ammonia, urea, or a combination thereof, or a mixture of ammonia or urea with another fluid, such as Deionized (DI) water.

In some environments, the exhaust apparatus further includes a Diesel Oxidation Catalyst (DOC) unit disposed in the exhaust line upstream of the particulate filter.

In some embodiments, the porous material of the honeycomb body comprises one or more selected from the group consisting of: cordierite, aluminum titanate, magnesium titanate, silicon carbide oxide, mullite, alumina, spinel, and combinations thereof.

In some embodiments, the exhaust treatment device further comprises one or more catalytic exhaust components disposed within the exhaust line housing.

In some of these embodiments, one or more of the catalytic exhaust components is selected from the group consisting of: DOC component, SCR component, and LNT component.

In some embodiments, the exhaust treatment device further comprises a reductant injector connected to the reductant injector node.

In some embodiments, the exhaust treatment device further comprises a reductant doser.

In some embodiments, the matrix of intersecting walls of the filter body includes cells in a pattern of 100 to 600 cells per square inch.

In some embodiments, the matrix of intersecting walls of the filter body includes cells in a substantially similar shaped cell pattern.

In some embodiments, the matrix of intersecting walls of the filter body includes cells in a substantially similar sized cell pattern.

In some embodiments, the outlet passage of the filter body is larger in area than the inlet passage of the filter body.

In some embodiments, at least one of the particulate filters further comprises a catalyst material disposed on, in, or both on and in at least a portion of the intersecting walls of the honeycomb body.

In some embodiments, the second particulate filter coats or supports an ammonia oxidation catalyst.

In some embodiments, the SCR includes an ammonia oxidation catalyst at the downstream end; in other embodiments, the SCR does not include an ammonia oxidation catalyst at the downstream end.

In various other embodiments disclosed herein, the particulate filter is a Diesel Particulate Filter (DPF), the construction comprising: doc+scr+doc+dpf+scr+dpf; SCR+DOC+DPF+SCR+DPF; SCR+DOC integrated DPF+SCR+DPF; doc+scr+doc integrated dpf+scr+dpf; DPF+SCR+DPF integrated with DOC.

11-14, the SCR integrated filter is not the most downstream component, but the SCR integrated filter is located downstream of the most downstream urea injector/mixer component.

Fig. 15 schematically shows an embodiment of an exhaust gas line comprising: a DOC, a mixer with reductant injection, an SCR, a conduit, a second DOC, a DPF, a second mixer with reductant injection, a second SCR, a third SCR, an ASC, a conduit, and a second DPF connected in fluid communication such that an exhaust gas stream may flow into an exhaust gas line and move in a downstream direction through the exhaust gas line assembly in series. The first DOC and the first SCR are referred to as near-connected or near-connected catalysts because they may be configured to be near-connected relative to the vehicle engine near the inlet of the exhaust line. In fig. 15, the "second DPF" or the most downstream DPF is downstream of all other upstream components and may function as an end trap for particulate matter before the exhaust gas exits the exhaust line.

Reference throughout this specification to "one embodiment," "certain embodiments," "one or more embodiments," or "an embodiment" means that a particular feature, structure, material, or characteristic described in connection with the embodiment is included in at least one embodiment of the present disclosure. Thus, appearances of the phrases such as "in one or more embodiments," "in some embodiments," "in one embodiment," or "in one embodiment" in various places throughout this specification are not necessarily referring to the same embodiment of the present disclosure. Furthermore, the particular features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments.

Although the disclosure herein has been described with reference to particular embodiments, those skilled in the art will appreciate that the embodiments described are merely illustrative of the principles and applications of the present disclosure. It will be apparent to those skilled in the art that various modifications and variations can be made in the method and apparatus of the present disclosure without departing from the scope or spirit of the disclosure. Accordingly, the present disclosure is intended to include modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.

Claims

1. An exhaust gas treatment device for treating an exhaust gas stream flowing in a downstream direction through an exhaust gas line housing from an upstream location to a downstream location of the exhaust gas line housing, the exhaust gas treatment device comprising:

a first particulate filter;

an SCR unit disposed downstream of the first particulate filter; and

a second particulate filter disposed downstream of the SCR unit;

wherein the first particulate filter, the SCR unit and the second particulate filter are arranged in series in the exhaust gas line housing and configured to allow the exhaust gas stream to flow in series through the first particulate filter, then through the SCR unit, and then through the second particulate filter.

2. The apparatus of claim 1, wherein the SCR unit comprises a reductant doser configured to inject reductant into the exhaust gas in the exhaust line housing downstream of the first particulate filter.

3. The apparatus of claims 1-2, wherein the SCR unit further comprises a selective catalyst reduction catalyst.

4. The apparatus of claims 1-3, wherein the first particulate filter comprises a first honeycomb body comprising intersecting porous ceramic walls comprising a first bulk average porosity measured by mercury porosimetry; and the second particulate filter comprises a second honeycomb body comprising intersecting porous ceramic walls comprising a second bulk average porosity measured by mercury porosimetry, wherein the second honeycomb body comprises a second bulk median pore diameter that is less than the first bulk median pore diameter of the first honeycomb body.

5. The apparatus of claims 1-4, wherein the first particulate filter comprises a first honeycomb body comprising intersecting porous ceramic walls comprising 40-65% of a first bulk average porosity measured by mercury porosimetry; and the second particulate filter comprises a second honeycomb body comprising intersecting porous ceramic walls comprising a second bulk average porosity of 35-55% measured by mercury porosimetry.

6. The apparatus of claim 5, wherein the first bulk average porosity is 48-62%.

7. The apparatus of claim 5, wherein the first bulk average porosity is 50-55%.

8. The apparatus of claims 5-7, wherein the second bulk average porosity is 40-55%.

9. The apparatus of claims 5-8, wherein the second honeycomb body comprises a second bulk median pore diameter of 5-22 microns.

10. The apparatus of claims 5-8, wherein the second honeycomb body comprises a second bulk median pore diameter of 6-22 microns.

11. The apparatus of claims 5-10, wherein the second honeycomb comprises a second bulk median pore size that is smaller than the first bulk median pore size of the first honeycomb.

12. The apparatus of claim 1, wherein the first particulate filter comprises a first honeycomb body comprising intersecting porous ceramic walls comprising a first bulk median pore diameter of 12-30 microns measured by mercury porosimetry; and the second particulate filter comprises a second honeycomb body comprising intersecting porous ceramic walls comprising a second bulk median pore diameter of 2-22 microns as measured by mercury porosimetry, and wherein the second bulk median pore diameter is less than the first bulk median pore diameter.

13. The apparatus of claim 1, wherein the first particulate filter comprises a honeycomb body comprising intersecting porous ceramic walls comprising a bulk average porosity of 40-65% measured by mercury porosimetry.

14. The apparatus of claim 13, wherein the porous ceramic wall comprises a bulk average porosity of 42-55% measured by mercury porosimetry.

15. The apparatus of claim 13, wherein the porous ceramic wall comprises a bulk median pore diameter of 5 to 15 μm as measured by mercury porosimetry.

16. The apparatus of claim 13, wherein the porous ceramic wall comprises a bulk median pore diameter of 7 to 12 μm as measured by mercury porosimetry.

17. The apparatus of claim 1, wherein the first particulate filter comprises a first honeycomb body comprising intersecting porous ceramic walls comprising a first bulk average porosity measured by mercury porosimetry; and the second particulate filter comprises a second honeycomb body comprising intersecting porous ceramic walls comprising a second bulk average porosity measured by mercury porosimetry, and the second bulk average porosity is greater than the first bulk average porosity.

18. The apparatus of claim 1, wherein the first particulate filter comprises a first honeycomb body comprising intersecting porous ceramic walls defining axial channels, wherein the first honeycomb body further comprises plugs selectively disposed in at least some of the axial channels to further define inlet and outlet channels and to provide a plurality of gas flow paths through selected porous ceramic walls.

19. The apparatus of claim 18, wherein at least some of the inlet channels have a cross-sectional channel open area that is greater than a cross-sectional channel open area of at least some of the outlet channels.

20. The apparatus of claim 18, wherein the second particulate filter comprises a second honeycomb body comprising intersecting porous ceramic walls defining axial channels, wherein the second honeycomb body further comprises plugs selectively disposed in at least some of the axial channels to further define inlet and outlet channels and to provide a plurality of gas flow paths through selected porous ceramic walls.

21. The apparatus of claim 20, wherein a majority of the inlet channels and a majority of the outlet channels in the second particulate filter have substantially the same cross-sectional channel open area.

22. A method of treating an exhaust stream, the method comprising:

the exhaust gas stream is caused to flow through a first particulate filter,

then, after flowing through the first particulate filter, the exhaust stream is caused to flow through an SCR unit,

the exhaust stream is then caused to flow through a second particulate filter after exposure to the selective catalytic reduction catalyst.

23. The method of claim 22, wherein in the SCR unit the exhaust stream is mixed with a reducing agent and the mixture of the exhaust stream and the reducing agent flows through a selective catalytic reduction catalyst.

24. The method of claim 22, wherein the exhaust stream is caused to flow through a second particulate filter after exposure to the selective catalytic reduction catalyst.

25. The method of claim 22, wherein the exhaust stream is exposed to an oxidation catalyst prior to entering the first particulate filter.

26. The method of claim 25, wherein the oxidation catalyst is a diesel oxidation catalyst.

27. The method of claim 22, wherein the exhaust stream entering the first particulate filter comprises exhaust gas and particulates.

28. The method of claim 27, wherein the exhaust stream entering the first particulate filter comprises soot particles.

29. The method of claim 27, wherein the exhaust stream entering the second particulate filter comprises particulates produced by the SCR unit.

30. The method of claim 27, wherein at least some particulates from the exhaust stream are removed by a first particulate filter.

31. The method of claim 27, wherein at least some of the soot particles from the exhaust stream are removed by the first particulate filter.

32. The method of claim 31, wherein more than 80% of the soot particles entering the first particulate filter are removed by the first particulate filter.

33. The method of claim 31, wherein at least some of the soot particles entering the second particulate filter are removed by the second particulate filter.

34. The method of claim 27, wherein flowing through the second particulate filter removes at least some particulates from the exhaust stream.

35. The method of claim 27, wherein the exhaust stream entering the second particulate filter comprises particulates produced by the SCR unit.

36. The method of claim 35, wherein flowing through the second particulate filter removes at least some particulates generated by the SCR unit entering the second particulate filter.

37. The method of claim 35, wherein flowing through the second particulate filter removes at least some particulates generated by the SCR unit entering the second particulate filter.

38. The method of claim 27, wherein exposing the exhaust stream with the reductant to the selective catalytic reduction catalyst adds SCR-produced particulates to the exhaust stream.

39. The method of claim 38, wherein the SCR-produced particles comprise SCR reaction byproduct particles.

40. The method of claim 38, wherein the second particulate filter is configured to remove at least some SCR reaction byproduct particles.

41. A method of treating an exhaust stream comprising exhaust gas and particulates, the method comprising:

flowing the exhaust stream through a first particulate filter configured to remove at least some particulates from the exhaust stream; then

Flowing the exhaust gas stream through the SCR unit, wherein a reducing agent is introduced into the exhaust gas stream; then

The exhaust gas stream is caused to flow through a second particulate filter configured to remove at least some particulates from the exhaust gas stream.

42. A method of treating an exhaust stream comprising exhaust gas and particulates, the method comprising:

Flowing the exhaust stream through the SCR unit, wherein a reducing agent is introduced into the exhaust gas stream to induce a selective catalytic reaction in the exhaust stream; then

43. The method of claim 42, wherein the selective catalytic reaction adds SCR-produced particulates to the exhaust gas stream, and the second particulate filter is configured to remove at least some of the SCR-produced particulates.

44. A method according to claim 42, wherein the particles entering the first particulate filter are predominantly soot particles.

45. The method of claim 42, wherein the selective catalytic reaction adds SCR-produced particulates to the exhaust gas stream, and the second particulate filter is configured to remove at least some of the SCR-produced particulates.

46. The method of claim 45, wherein the SCR generated particles comprise NH ₃ And (3) base particles.

47. The method of claim 42, further comprising regenerating the first particulate filter while the exhaust stream flows through the second particulate filter.

48. The method of claim 47, wherein the first particulate filter has an internal temperature of greater than 550 ℃ during regeneration.

49. An exhaust gas treatment device for treating an exhaust gas stream flowing in a downstream direction through an exhaust gas line housing from an upstream location to a downstream location of the exhaust gas line housing, the exhaust gas treatment device comprising:

An upstream component comprising at least one particulate filter and one or more SCR units; and

a final particulate filter disposed upstream of the upstream assembly.

50. The exhaust treatment device of claim 49, wherein the upstream assembly further comprises: one or more Diesel Oxidation Catalyst (DOC) assemblies; one or more urea injector assemblies; one or more mixing duct assemblies; one or more Ammonia Slip Catalyst (ASC) assemblies; and/or one or more electrically heatable components comprising one or more heater components and/or one or more Electrically Heatable Catalyst (EHC) components.

51. The exhaust treatment device of claims 49-50, wherein at least one of the upstream components is configured to be mounted proximate to the connection.