(19) United States
`(12) Patent Application Publication (10) Pub. No.: US 2006/0039843 A1
`
` Patchett et al. (43) Pub. Date: Feb. 23, 2006
`
`
`US 20060039843A1
`
`(54) ZONE COATED CATALYST TO
`SIMULTANEOUSLY REDUCE Nox AND
`UNREACTED AMMONIA
`
`(57)
`
`ABSTRACT
`
`(75)
`
`Inventors: Joseph Allan Patchett, Basking Ridge,
`NJ (us); Joseph Charles Dettling,
`Howell, NJ (US)
`
`CorreSpondence Address:
`ENGELHARD CORPORATION
`101 WOOD AVENUE
`ISELIN, NJ 08830 (US)
`
`(73) Assignee: ENGELHARD CORPORATION
`
`(21) Appl. NO.I
`
`10/925,018
`
`(22)
`
`Filed:
`
`Aug. 23, 2004
`
`Publication Classification
`
`(51)
`
`Int. Cl.
`(200601)
`301D 53/56
`(52) US. Cl.
`...................... 423/2391; 422’177; 422/180;
`422/172
`
`Provided is an emissions treatment system and method for
`reducing NOx emissions in the exhaust stream produced
`from an internal combustion engine. The system has an
`injector for periodically metering ammonia or an ammonia
`precursor into an exhaust stream; and a first substrate with
`a first SCR catalyst composition, downstream of the injector.
`The first substrate has an inlet end, an outlet end, a length
`extending between the inlet end to the outlet end, wall
`elements and a plurality of passages defined by the wall
`elements. The first SCR catalyst composition is disposed on
`the wall elements from the inlet end toward the outlet end to
`a length that is less than the substrate’s axial length to form
`an inlet ZOIIC.
`
`The first substrate also has an NH3 destruction catalyst
`composition with a platinum group metal component dis-
`persed on a refractory metal oxide. The NH3 destruction
`catalyst is disposed on the wall elements from the outlet end
`toward the inlet end to a length that
`is less than the
`substrate’s axial length to form an outlet zone. Generally,
`there is from 0.1 to 10 g/ft3 of platinum group metal
`component in the outlet zone.
`
` ENGINE
`
` 27
`
`12
`
`Umicore AG & Co. KG
`Exhibit 1105
`Page1 of 22
`
`Umicore AG & Co. KG
`Exhibit 1105
`Page 1 of 22
`
`

`

`Patent Application Publication Feb. 23, 2006 Sheet 1 0f 10
`
`US 2006/0039843 A1
`
`Figure 1
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`
`Umicore AG & Co. KG
`Exhibit 1105
`Page 2 of 22
`
`Umicore AG & Co. KG
`Exhibit 1105
`Page 2 of 22
`
`

`

`Patent Application Publication Feb. 23, 2006 Sheet 2 0f 10
`
`US 2006/0039843 A1
`
`25 ENGINE
` 25 a 3%
`
`FigureSB
`
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`
`Umicore AG & Co. KG
`Exhibit 1105
`Page 3 of 22
`
`Umicore AG & Co. KG
`Exhibit 1105
`Page 3 of 22
`
`

`

`Patent Application Publication Feb. 23, 2006 Sheet 3 0f 10
`
`US 2006/0039843 A1
`
`12
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`
`Umicore AG & Co. KG
`Exhibit 1105
`Page 4 of 22
`
`Umicore AG & Co. KG
`Exhibit 1105
`Page 4 of 22
`
`

`

`Patent Application Publication Feb. 23, 2006 Sheet 4 0f 10
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`US 2006/0039843 A1
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`

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`Patent Application Publication Feb. 23, 2006 Sheet 5 0f 10
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`US 2006/0039843 A1
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`Umicore AG & Co. KG
`Exhibit 1105
`Page 6 of 22
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`

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`Patent Application Publication Feb. 23, 2006 Sheet 6 0f 10
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`US 2006/0039843 A1
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`

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`Patent Application Publication Feb. 23, 2006 Sheet 9 0f 10
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`US 2006/0039843 A1
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`Umicore AG & Co. KG
`Exhibit 1105
`Page 10 of 22
`
`Umicore AG & Co. KG
`Exhibit 1105
`Page 10 of 22
`
`

`

`Patent Application Publication Feb. 23, 2006 Sheet 10 0f 10
`
`US 2006/0039843 A1
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`Page 11 of 22
`
`Umicore AG & Co. KG
`Exhibit 1105
`Page 11 of 22
`
`

`

`US 2006/0039843 A1
`
`Feb. 23, 2006
`
`ZONE COATED CATALYST TO
`SIMULTANEOUSLY REDUCE NOX AND
`UNREACTED AMMONIA
`
`[0001] The present invention relates to an emissions treat-
`ment system and method for reducing nitrogen oxides
`(NOx) emissions in the exhaust stream produced from an
`internal combustion engine.
`
`Internal combustion engines that operate at com-
`[0002]
`bustion conditions with large excesses of air over that
`required for stoichiometric combustion, i.e., lean conditions,
`present particular difficulties in removing NOx from their
`exhaust gases. For instance, many diesel powered vehicles
`will require NOx specific abatement strategies to meet future
`emissions standards adopted throughout the world.
`
`[0003] A proven NOx abatement technology applied to
`stationary sources with lean exhaust conditions is Selective
`Catalytic Reduction (SCR) using ammonia (NH3) or an NH3
`precursor.
`In processes using this technology, NOx is
`reduced with ammonia (NHS)
`to nitrogen (N2) over a
`catalyst that is typically composed of base metal oxides. The
`technology is capable of NOx reduction greater than 90%,
`and thus it represents one of the best approaches for achiev-
`ing aggressive NOx reduction goals. SCR is under devel-
`opment for mobile applications, with urea (typically present
`in an aqueous solution) as the source of ammonia. SCR
`provides efficient conversions of NOx as long as the exhaust
`temperature is within the active temperature range of the
`catalyst.
`
`[0004] The use of a reductant such as ammonia requires
`that the ammonia be metered into the exhaust system in
`quantities proportional to the amount of NOx in the exhaust
`gas so that adequate NOx treatment is achieved, and so that
`large excesses of ammonia do not pass unreacted through the
`exhaust system. Ammonia in the exhaust can contribute to
`particulates and,
`in high concentrations, can lead to a
`distinctive and irritating odor.
`
`[0005] Diesel engines operate under transient conditions,
`that is the engine speed and load vary over a time interval of
`a few seconds. The amount of NOx in the exhaust stream
`
`varies in concert with the changing operating conditions,
`and accordingly, the amount of the reactant ammonia that is
`metered into the exhaust must
`likewise be metered in
`
`proportion to the NOx in the exhaust. Theoretically, provid-
`ing ammonia in excess of
`the stoichiometric amount
`required to react completely with the nitrogen oxides
`present, is favorable for driving the reaction to completion.
`However, in practice, furnishing the system with significant
`excess ammonia over such stoichiometric amount is not
`
`done because of the liability of discharging unreacted
`ammonia to the atmosphere.
`
`[0006] Such discharge of unreacted ammonia can occur
`even in cases where ammonia is present only in a stoichio-
`metric or sub-stoichiometric amount, as a result of incom-
`plete reaction and/or poor mixing of the ammonia in the
`gaseous stream, resulting in the formation therein of chan-
`nels of high ammonia concentration. Such channeling is of
`particular concern when utilizing catalysts comprising
`monolithic honeycomb-type carriers comprising refractory
`bodies having a plurality of fine, parallel gas flow paths
`extending therethrough. Unlike the case of beds of particu-
`late catalyst, there is no opportunity for gas mixing between
`channels.
`
`[0007] Provisions are often included in SCR catalyst sys-
`tems to regulate the dosing of the reductant to account for
`changes in the engine operating conditions. Yet despite
`sophisticated dosing controls, the vehicle may operate under
`conditions that result in excess ammonia passing un-reacted
`through the SCR catalyst bed as part of the engine exhaust.
`
`[0008] Another strategy that can be used in combination
`with the ammonia dosing controls described above is to
`include an NH3 destruction catalyst downstream of the SCR
`catalyst. The staging of the SCR catalyst with a downstream
`NH3 destruction catalyst provides an emissions treatment
`system that can oxidize excess ammonia that is not con-
`sumed in the SCR reaction to N2. Thus, the system can in
`principle accommodate injection of amounts of ammonia
`into the exhaust stream that are greater than the stoichio-
`metric amount needed to treat the NOx, with diminished risk
`of ammonia discharge into the atmosphere.
`
`[0009] The prior art describes staged catalysts that com-
`bine an upstream SCR catalyst zone and a downstream NH3
`oxidation zone. These references are described below.
`
`[0010] US. Pat. No. 3,970,739 discloses a process for
`stripping ammoniacal nitrogens and organic materials, as
`gases, which are present
`in process waste waters to be
`discharged from plants. The gases are used in ammonia
`synthesis, and are manufactured by reforming hydrocarbon
`with steam. The process includes decomposing organic
`materials selectively in the presence of a catalyst at a
`temperature of about 120 to 400° C., mixing the remaining
`gases with flue gases that contain NOx, reacting the gaseous
`mixture over a catalyst at a temperature of about 150 to 700°
`C., and decomposing the unreacted ammonia, if any, in the
`presence of a catalyst at a temperature of about 150 to 700
`° C. to render the nocuous substances innocuous.
`
`[0011] A staged NOx treatment—NH3 oxidation system is
`also described for treatment of a combusted gas stream from
`a hydrocarbon burning engine that contains nitric oxide in
`US. Pat. No. 4,188,364 (“the ”364 patent”). The nitric oxide
`is reacted with ammonia over a first catalyst comprising
`inorganic oxides and then the excess ammonia is reacted
`with oxygen over a second catalyst to form a substantially
`nitric oxide free and ammonia free exhaust stream. Gener-
`
`ally, the second catalyst is disclosed to comprise a Group
`VIII noble metal such as platinum, palladium, ruthenium
`rhodium, osmium, iridium or the like or mixture thereof
`included on a porous solid catalyst, generally a porous
`inorganic oxide carrier such as alumina or the like.
`
`[0012] US. Pat. No. 4,438,082 (“the ”082 patent”) dis-
`closes, among other things, a two-stage catalyst system
`having a first stage comprised of VZOS/AIZO3 and a second
`stage comprised of Pt/Au/A1203. The vanadium pentoxide
`catalyst is said to provide ideal catalytic action between 300
`and 550° C., and the platinum gold catalysts are useful in
`reducing NOx with ammonia with oxygen over the range of
`from about 225 to 400° C. The platinum gold catalyst is said
`to be useful for either reducing NOx in gas streams with the
`temperature range of from about 225 to 400° C., or if the
`platinum gold catalyst
`is used following the vanadium
`pentoxide catalysts, then effective reduction of NOx may be
`carried out by the system over the range of about 225 to 550°
`C. In one configuration disclosed in the ’082 patent, one end
`of a single support may be coated with vanadium pentoxide
`while the other end may be coated with the platinum gold
`catalyst.
`
`Umicore AG & Co. KG
`Exhibit 1 105
`Page 12 of 22
`
`Umicore AG & Co. KG
`Exhibit 1105
`Page 12 of 22
`
`

`

`US 2006/0039843 A1
`
`Feb. 23, 2006
`
`[0013] A two zone catalyst system for catalytic reduction
`of NOx is also disclosed in US. Pat. No. 5,024,981 (“the
`’981 patent”). A first or upstream zone of the system has a
`zeolite catalyst composition that has as a lower metal (e.g.,
`iron or copper) promoter loading than the metal promoter
`loading of the second zone or downstream zone, which also
`comprises a zeolite catalyst composition. The catalyst com-
`position in the first zone is said to favor reduction of nitrogen
`oxides and the second catalyst is said to favor the oxidation
`or decomposition of excess ammonia.
`
`[0014] U.S. Pat. No. 5,120,695 (“the ’695 patent”) dis-
`closes a one piece catalyst for purifying exhaust gases from
`internal combustion engines and gas turbines that are oper-
`ated above the stoichiometric ratio. The one-piece honey-
`comb ceramic or metallic carrier has a reduction catalyst on
`its leading edge portion and an oxidation catalyst on its
`trailing edge portion. Exhaust gases are brought into contact
`in immediate succession in the single honeycomb-form with
`catalyst zones called zone 1, for the reduction part, and zone
`2, for the oxidation part. The catalyst can be completely in
`the form of a carrier catalyst or alternatively can be a solid
`catalyst coated with the oxidation catalyst in zone 2.
`
`[0015] Among the reduction catalysts that are disclosed to
`be useful in the ’695 patent are various titanium oxides-
`containing catalysts and acid resistant zeolite full
`type
`catalyst, optionally of mordenite type, containing copper,
`iron and optionally, cerium or molybdenum. The oxidation
`catalysts disclosed to be useful for zone 2 include noble
`metal-containing compositions (e.g., platinum, palladium,
`and rhodium).
`
`[0016] A number of the above-described staged emissions
`treatment system use NH3 destruction catalyst compositions
`that include platinum group metal components. This simi-
`larity can no doubt be reconciled with the recognized
`advantages of incorporating platinum group metal compo-
`nents into the NH3 destruction catalyst compositions. For
`instance, platinum group metal-based catayst compositions
`have a low “light-off temperature” for ammonia conversion
`(temperature at which 50% NH3 removal is observed). In
`addition, platinum group metal-based compositions are
`effective in combusting unburned hydrocarbons including
`gaseous hydrocarbons and liquid hydrocarbons (the soluble
`organic fraction of the particulate or “SOF”). This feature is
`particularly significant for emissions treatment systems that
`do not employ a separate diesel oxidation catalyst (DOC)
`substrate, and instead, use a staged SCR catalyst and NH3
`destruction catalyst as a stand alone system.
`
`:0017] A drawback associated with use of platinum group
`netals, and in particular, platinum in the NH3 destruction
`catalysts is that excess ammonia may be oxidized to form
`\IOx instead of the innocuous products N2 and H20. This
`drawback undermines efforts to reduce NOx in the exhaust
`DClOW mandated levels.
`
`
`
`SUMMARY OF THE INVENTION
`
`In one aspect, the invention relates to an emissions
`:0018]
`reatment system. The treatment system has an injector for
`aeriodically metering ammonia or an ammonia precursor
`into an exhaust stream. The treatment system also has a first
`substrate with a first SCR catalyst composition, which is
`aositioned downstream of the injector. The first substrate has
`an inlet end, an outlet end, a length extending between the
`
`inlet end to the outlet end, wall elements and a plurality of
`passages defined by the wall elements. The first SCR cata-
`lyst composition is disposed on the wall elements from the
`inlet end toward the outlet end to a length that is less than
`the substrate’s axial length to form an inlet zone.
`
`[0019] The first substrate also has an NH3 destruction
`catalyst composition comprising a platinum group metal
`component dispersed on a refractory metal oxide, wherein
`the NH3 destruction catalyst is disposed on the wall elements
`from the outlet end toward the inlet end to a length that is
`less than the substrate’s axial length to form an outlet zone.
`There is from 0.1 to 10 g/ft3 of platinum group metal
`component in the outlet zone. In some embodiments, the
`NH3 destruction catalyst composition further contains a
`cerium component, which is preferably in bulk form.
`
`[0020] The platinum group metal component can be
`selected from the group consisting of platinum, palladium,
`rhodium, iridium and combinations thereof. Preferably, the
`NH3 destruction catalyst contains a platinum component.
`The catalytic activity of the platinum component can be
`moderated by sulfating the platinum component.
`
`In some embodiments of the emissions treatment
`[0021]
`system, the first SCR catalyst composition contains V205,
`WO3 and TiOz. In other embodiments, the first SCR catalyst
`composition contains a copper-exchanged zeolite.
`
`[0022] Typically, there is an uncoated zone of at least 0.25
`inches between the inlet and outlet zones in the first sub-
`strate.
`
`[0023] The first substrate is typically a honeycomb flow-
`through substrate. However, in some embodiments of the
`emissions treatment system, the first substrate is a honey-
`comb wall flow substrate.
`
`In some embodiments of the emissions treatment
`[0024]
`there is a diesel engine upstream and in fluid
`system,
`communication with the injector.
`
`In a preferred embodiment of the invention, the
`[0025]
`emission treatment system has a second substrate interposed
`and in fluid communication with the injector and the first
`substrate. The second substrate may be,
`for example,
`selected from the group consisting of a honeycomb flow-
`through substrate, an open-cell foam substrate and a hon-
`eycomb wall flow substrate. Preferably the second substrate
`is a honeycomb flow-through substrate with a second SCR
`catalyst composition. The first and second SCR catalyst
`compositions used to coat the first and second substrates,
`respectively, may be the same or different. However, in one
`preferred embodiment of the invention, the first and second
`SCR catalyst compositions are the same.
`
`In another aspect, the invention relates to a method
`[0026]
`for reducing NOx emissions in the exhaust stream produced
`from an internal combustion engine. The method includes:
`
`(a) metering at periodic intervals ammonia or an
`[0027]
`ammonia precursor into the exhaust stream; and
`
`(b) passing the exhaust stream through a first
`[0028]
`substrate comprising a first SCR catalyst composition.
`
`[0029] Optionally, the method further includes (a1) pass-
`ing the exhaust stream through a second substrate after (a)
`and prior to (b).
`
`Umicore AG & Co. KG
`Exhibit 1105
`Page 13 of 22
`
`Umicore AG & Co. KG
`Exhibit 1105
`Page 13 of 22
`
`

`

`US 2006/0039843 A1
`
`Feb. 23, 2006
`
`In the method, the first substrate has an inlet end,
`[0030]
`an outlet end, a length extending between the inlet end to the
`outlet end, wall elements and a plurality of passages defined
`by the wall elements. The first SCR catalyst composition is
`disposed on the wall elements from the inlet end toward the
`outlet end to a length that is less than the substrate’s axial
`length to form an inlet zone.
`
`[0031] The NH3 destruction catalyst composition includes
`a platinum group metal component (preferably a platinum
`component) dispersed on a refractory metal oxide, wherein
`the NH3 destruction catalyst is disposed on the wall elements
`from the outlet end toward the inlet end to a length that is
`less than the substrate’s axial length to form an outlet zone.
`There is from 0.1 to 10 g/ft3 of platinum group metal
`component in the outlet zone.
`
`the
`In optional embodiments of the invention,
`[0032]
`second substrate of (a1) is selected from the group consist-
`ing of a honeycomb flow-through substrate, an open-cell
`foam substrate and a honeycomb wall flow substrate. Pref-
`erably, the second substrate of (a1) is a honeycomb flow-
`through substrate having a second SCR catalyst composi-
`tion. Preferably,
`the
`first
`and second SCR catalyst
`compositions are the same.
`
`the method is conducted wherein the
`[0033] Generally,
`amount of ammonia or ammonia precursor metered into the
`exhaust stream provides a normalized stoichiometric ratio of
`between 0.2 to 2.0.
`
`the exhaust stream in the first
`In the method,
`[0034]
`substrate preferably has a space velocity of from 30,000 to
`90,000 hr"1 at rated power.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`:0035] FIG. 1 is a perspective view of a honeycomb
`substrate.
`
`:0036] FIG. 2 is a sectional view of the honeycomb
`substrate of FIG. 1 along Section 2-2.
`
`:0037] FIGS. 3A, 3B and 3C are schematic depictions of
`hree embodiments of the emissions treatment system of the
`invention.
`
`
`
`FIGS. 4 illustrates an exemplary coating architec-
`:0038]
`ure in sectional view of a single passage of honeycomb flow
`hrough substrate.
`
`:0039] FIG. 5 illustrates a cutaway section of a typical
`substrate of the foam-type.
`
`:0040] FIG. 6 shows % NOx conversion for test gas
`emperature for a zone coated Catalyst Substrate A1.
`
`:0041] FIG. 7 shows % NH3 removal for test gas tem-
`aerature for a zone coated Catalyst Substrate A1.
`
`:0042] FIG. 8 shows % NH3 removal and % NOx con-
`version for catalyst substrates coated with a platinum-based
`VH3 destruction catalyst compositions using a test gas
`composition with a space velocity of 50,000 h'l.
`
`'0043] FIG. 9 shows % NH3 removal and % NOx con-
`version for catalyst substrates coated with a platinum-based
`'\IH3 destruction catalyst compositions using a test gas
`composition with a space velocity of 100,000 h'l.
`
`[0044] FIG. 10 shows % NH3 removal % NOx make, and
`% N20 make for catalyst substrates coated with a NH3
`destruction catalyst compositions containing 2 g/ft3 of plati-
`num.
`
`DEFINITIONS
`
`[0045] The following terms shall have, for the purposes of
`this application, the respective meanings set forth below.
`
`“Activated alumina” has its usual meaning of a
`[0046]
`high BET surface area alumina, comprising one or more of
`gamma-, theta- and delta aluminas.
`
`“At rated power” refers to the maximum power
`[0047]
`output of the engine.
`
`“BET surface area” has its usual meaning of refer-
`[0048]
`ring to the Brunauer, Emmett, Teller method for determining
`surface area by N2 absorption. Unless otherwise specifically
`stated, all references herein to the surface area of the catalyst
`support components or other catalyst components means the
`BET surface area.
`
`“Bulk form,” when used to describe the physical
`[0049]
`form of a material (e.g., ceria), means the material is present
`as discrete particles that can be as small as 1 to 15 microns
`in diameter or smaller, as opposed to having been dispersed
`in solution onto another material such as gamma alumina.
`By way of example, in some embodiments of the invention,
`particles of ceria are admixed with particles of gamma
`alumina so that ceria is present in bulk form, as opposed to,
`for example, impregnating alumina particles with aqueous
`solutions of ceria precursors which upon calcination are
`converted to ceria disposed on the alumina particles.
`
`“Cerium component” means one or more oxides of
`[0050]
`cerium (e.g., CeOZ).
`
`“Downstream” and “Upstream,” when used to
`[0051]
`describe an article, catalyst substrate or zone, refer to the
`relative positions in the exhaust system as sensed in the
`direction of the flow of the exhaust gas stream.
`
`“High surface area support” means support mate-
`[0052]
`rials with a BET surface area that is approximately greater
`than 10 mZ/g, preferably greater than 150 mZ/g.
`
`“Platinum group metal component” refers to the
`[0053]
`platinum group metals or oxides thereof. Preferred platinum
`group metal components are platinum, palladium, rhodium
`iridium components, and combinations thereof.
`
`DETAILED DESCRIPTION OF THE
`INVENTION
`
`[0054] Applicants have found a system that incorporates
`an integrated catalyst article having an SCR catalyst and
`NH3 destruction catalyst on a single substrate that simulta-
`neously provides efficient NOx conversion and destruction
`of excess ammonia. The catalyst article is composed of a
`coated substrate having two catalytic zones, an inlet zone
`suited for the SCR reaction and an outlet zone suited for the
`
`destruction (oxidation) of NH3.
`
`[0055] One desirable feature of the article is that the outlet
`zone (NH3 destruction catalyst-containing zone) can accom-
`modate the inevitable excesses of ammonia that emerge
`from the inlet zone (SCR catalyst-containing zone) due to
`the factors noted above, without forming NOx from the
`
`Umicore AG & Co. KG
`Exhibit 1 105
`Page 14 of 22
`
`Umicore AG & Co. KG
`Exhibit 1105
`Page 14 of 22
`
`

`

`US 2006/0039843 A1
`
`Feb. 23, 2006
`
`excess ammonia. Applicant has found that by limiting the
`amount of platinum group metal component in the NH3
`destruction catalyst (e.g., less than 10 g/ft3, preferably less
`than 5 g/ft3), effective and selective conversion of ammonia
`to N2 and H20 is provided without NOx formation. Emis-
`sions treatment systems that employ the inventive zoned
`articles can reduce NOx to N2 while simultaneously provid-
`ing for at least partial abatement of other components of the
`exhaust including unburned gaseous hydrocarbons, CO, and
`the SOF.
`
`[0056] Another desirable feature of employing the zoned
`SCR-NH3 destruction catalyst in emissions treatment sys-
`tems is a space-saving benefit gained by integrating two
`catalyst functions on a single substrate. In some embodi-
`ments of the invention, the integration of catalyst functions
`also eases the burden of housing additional catalyst sub-
`strates in canisters in the exhaust system (often also referred
`to as “canning substrates”).
`
`In addition to oxidizing any breakthrough NH3
`[0057]
`passing through unreacted through the inlet zone to N2 and
`H20, the outlet zone of the zoned articles is also capable of
`oxidizing CO and gaseous hydrocarbons in the exhaust to
`CO, and water. Catalysts suitable for the oxidation of ammo-
`nia have also been shown to be effective in treating the SOF
`in the diesel exhaust which also contributes to particulate
`emissions. Such catalysts are preferably formulated to mini-
`mize the oxidation of SO2 to SO3 because emissions of SO3
`also contribute to particulate emissions.
`
`[0058] FIGS. 1 and 2 illustrate a typical honeycomb-type
`flow through substrate that can be used in the articles of the
`invention. The honeycomb flow through substrate 10 has an
`outer surface 12, an inlet end 14 and an outlet end 14’. There
`is a plurality of parallel passages 16 defined by the sub-
`strate’s wall elements 18. Each passage has a corresponding
`inlet and outlet. The catalyst is coated on the wall elements
`so that the gases flowing through the passages contact the
`catalyst. The substrate has different coated zones 20 (inlet
`zone) and 21 (outlet zone) along the length of the passages.
`In the embodiment shown in FIG. 2, there is also a short,
`uncoated zone 22 between the coated zones.
`
`[0059] FIG. 4 depicts a single passage of a zoned coated
`honeycomb flow through substrate 10 having an inlet end
`14, an outlet end 14‘, wall elements 18, a passage defined by
`the wall elements 16, an inlet zone 20 and a outlet zone 21.
`The inlet zone has an SCR catalyst composition 28 disposed
`on the wall elements from the inlet end toward the outlet end
`
`to a length that is less than the substrate’s axial length. The
`outlet zone has an NH3 destruction catalyst composition 29
`disposed on the wall elements from the outlet end toward the
`inlet end to a length that is less then the substrate’s axial
`length. An uncoated segment of the wall elements forms an
`uncoated zone 22 along the axial length of the substrate.
`
`[0060] One embodiment of the inventive emissions treat-
`ment system denoted as 10A is schematically depicted in
`FIG. 3A. The exhaust, containing gaseous pollutants
`(including unburned hydrocarbons, carbon monoxide and
`NOx) and particulate matter, is conveyed from the engine 19
`to a position downstream in the exhaust system where a
`reductant, i.e., ammonia or an ammonia-precursor, is added
`to the exhaust stream. The reductant is injected as a spray via
`a nozzle (not shown) into the exhaust stream. Aqueous urea
`shown on one line 25 can serve as the ammonia precursor
`
`which can be mixed with air on another line 26 in a mixing
`station 24. Valve 23 can be used to meter precise amounts of
`aqueous urea which are converted in the exhaust stream to
`ammonia.
`
`[0061] The exhaust stream with the added ammonia is
`conveyed to the zoned SCR-NH3 destruc ion catalyst sub-
`strate 12 (also referred to herein including the claims as “the
`first substrate”). On passing through the irst substrate 12,
`the NOx component of the exhaust stream is converted
`through the selective catalytic reduction of NOx with NH3
`to N2 and H20. In addition, excess NH3 tiat emerges from
`the inlet zone is converted through oxidation in the outlet
`zone to N2 and H20. Moreover,
`it
`is noted that other
`components of the exhaust are combustec by the action of
`the SCR catalyst and NH3 destruction cata yst. For instance,
`typically at least some portion of the unburned gaseous
`hydrocarbons, carbon monoxide and particulate matter in
`the exhaust stream is converted to innoc10us components
`through contact with the catalytic compositions of the first
`substrate. The first substrate is typically a flow through
`monolith substrate.
`
`
`
`[0062] An alternative embodiment of the emissions treat-
`ment system, denoted as 11B is depicted in FIG. 3B which
`contains a second substrate 27 interposed between the NH3
`injector and the first substrate 12. In this embodiment, the
`second substrate is coated with an SCR catalyst composition
`which may be the same composition as is used to coat the
`first substrate 13 or a different composition. An advanta-
`geous feature of this embodiment is that the SCR catalyst
`compositions that are used to coat the substrate can be
`selected to optimize NOx conversion for the operating
`conditions characteristic of that site along the exhaust sys-
`tem. For example, the second substrate can be coated with
`an SCR catalyst composition that is better suited for higher
`operating temperatures experienced in upstream segments of
`the exhaust system, while another SCR composition can be
`used to coat the first substrate (i.e., the inlet zone of the first
`substrate) that is better suited to cooler exhaust temperature
`which are experienced in downstream segments of the
`exhaust system.
`
`In the embodiment depicted in FIG. 3B, the second
`[0063]
`substrate 27 can either be a honeycomb flow through sub-
`strate, an open cell foam substrate or a honeycomb wall flow
`substrate. In configurations of this embodiment where the
`second substrate is a wall flow substrate or a high efficiency
`open cell foam filter, the system can remove greater than
`80% of the particulate matter including the soot fraction and
`the SOF. An SCR-coated wall flow substrate and its utility
`in the reduction of NOX and particulate matter have been
`described, for instance, in co-pending US. patent applica-
`tion Ser. No. 10/634,659, filed Aug. 5, 2003, the disclosure
`of which is hereby incorporated by reference.
`
`In some applications it may be advantageous to
`[0064]
`include an oxidation catalyst upstream of the site of ammo-
`nia/ammonia precursor
`injection. For
`instance,
`in the
`embodiment depicted in FIG. 3C an oxidation catalyst is
`disposed on a catalyst substrate 34. The emissions treatment
`system 11C is provided with the first substrate 12 and
`optionally includes a second substrate 27. In this embodi-
`ment, the exhaust stream is first conveyed to the catalyst
`substrate 34 where at least some of the gaseous hydrocar-
`bons, CO and particulate matter are combusted to innocuous
`
`Umicore AG & Co. KG
`Exhibit 1105
`Page 15 of 22
`
`Umicore AG & Co. KG
`Exhibit 1105
`Page 15 of 22
`
`

`

`US 2006/0039843 A1
`
`Feb. 23, 2006
`
`components. In addition, a significant fraction of the N0 of
`the NOx component of the exhaust is converted to N02.
`Higher proportions of NO2 in the NOx component facilitate
`the reduction of NOx to N2 and H20 on the SCR catalyst(s)
`located downstream.
`
`SCR Catalyst Compositions
`
`[0065] Suitable SCR catalyst compositions that may be
`used to coat the inlet zone of the first substrate and/or the
`second substrate (in embodiments depicted in FIG. 3B) are
`described, for instance, in U.S. Pat. No. 4,961,917 (the ”917
`patent) and U.S. Pat. No. 5,516,497 (the ”497 patent), which
`are both hereby incorporated by reference in their entirety.
`Compositions disclosed in the ”917 patent include one or
`30th of an iron and a copper promoter present in a zeolite in
`an amount of from about 0.1 to 30 percent by weight,
`3referably from about 1 to 5 percent by weight, of the total
`weight of