# US 9,517,456 B2 · Catalyzed SCR filter and emission treatment system

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- Number: US 9,517,456 B2
- Document ID: US9517456B2
- Status: Granted
- Kind: B2
- Application number: 15/054,753
- Filed: 2016-02-26
- Published: 2016-06-23
- Granted: 2016-12-13
- Earliest claimed: 2003-08-05
- Assignees: BASF SE
- Applicants: BASF Corporation
- Inventors: Joseph A. Patchett; Joseph C. Dettling; Elizabeth A. Przybylski
- Web page: https://patentgrep.com/patent/US9517456B2

## CPC

- B01J 29/7615: {Zeolite Beta}
- B01D 5/0054: {General arrangements, e.g. flow sheets}
- B01D 5/009: {Collecting, removing and/or treatment of the condensate}
- B01D 19/0005: {with one or more auxiliary substances}
- B01D 19/0036: {Flash degasification (the other groups take precedence)}
- B01D 53/9413: {Processes characterised by a specific catalyst}
- B01D 53/9418: {for removing nitrogen oxides by selective catalytic reduction [SCR] using a reducing agent in a lean exhaust gas}
- B01D 53/945: {characterised by a specific catalyst}
- B01D 53/9477: {with catalysts positioned on separate bricks, e.g. exhaust systems}
- B01J 29/76: Iron group metals or copper
- B01J 35/657: {larger than 1000 nm}
- B01J 37/0236: {Drying, e.g. preparing a suspension, adding a soluble salt and drying}
- B01J 37/024: {Multiple impregnation or coating}
- B01J 37/0246: {Coatings comprising a zeolite}
- B01J 37/08: Heat treatment {(B01J37/0009, B01J37/0018 take precedence)}
- F01N 3/0231: {using special exhaust apparatus upstream of the filter for producing nitrogen dioxide, e.g. for continuous filter regeneration systems [CRT]}
- F01N 3/10: by thermal or catalytic conversion of noxious components of exhaust
- F01N 3/106: {Auxiliary oxidation catalysts}
- F01N 3/2066: {Selective catalytic reduction [SCR]}
- F01N 3/2828: {Ceramic multi-channel monoliths, e.g. honeycombs}
- F01N 3/2892: {Exhaust flow directors or the like, e.g. upstream of catalytic device}
- F01N 13/009: {having two or more separate purifying devices arranged in series}
- B01D 53/944: {Simultaneously removing carbon monoxide, hydrocarbons or carbon making use of oxidation catalysts (three-way-catalysts [TWC] B01D53/9445)}
- B01D 2251/2062: Ammonia
- B01D 2251/2067: Urea
- B01D 2255/102: Platinum group metals
- B01D 2255/20715: Zirconium
- B01D 2255/20738: Iron
- B01D 2255/20761: Copper
- B01D 2255/50: Zeolites
- B01D 2255/502: Beta zeolites
- B01D 2255/9155: Wall flow filters
- B01D 2255/9202: Linear dimensions
- B01D 2255/9205: Porosity
- B01D 2257/404: Nitrogen oxides other than dinitrogen oxide
- B01D 2258/012: Diesel engines and lean burn gasoline engines
- B01J 35/56: Foraminous structures having flow-through passages or channels, e.g. grids or three-dimensional [3D] monoliths
- F01N 2330/06: Ceramic, e.g. monoliths
- F01N 2330/30: Honeycomb supports characterised by their structural details
- F01N 2370/04: Zeolitic material
- F01N 2510/063: zeolites
- F01N 2610/02: the substance being ammonia or urea
- F01N 2610/08: with prior mixing of the substances with a gas, e.g. air
- Y02T 10/12: Improving ICE efficiencies
- Y10S 55/10: Residue burned
- Y10S 55/30: Exhaust treatment
- Y10T 29/49345: Catalytic device making
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- F01N: GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES (arrangements in connection with gas exhaust of propulsion units in vehicles B60K13/00; combustion-air intake silencers specially adapted for, or arranged on, internal-combustion engines F02M35/00; protecting against, or damping, noise in general G10K11/16)
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

Provided is a catalyst article for simultaneously remediating the nitrogen oxides (NOx), particulate matter, and gaseous hydrocarbons present in diesel engine exhaust streams. The catalyst article has a soot filter coated with a material effective in the Selective Catalytic Reduction (SCR) of NOx by a reductant, e.g., ammonia.

## Claims

### Claim 1

An emission treatment system for treatment of an exhaust stream comprising NOx and particulate matter, the system comprising:
an oxidation catalyst upstream of a soot filter comprising a wall flow monolith and an SCR catalyst composition;
wherein the wall flow monolith has a plurality of longitudinally extending passages formed by longitudinally extending walls bounding and defining said passages, wherein the passages comprise inlet passages having an open inlet end and a closed outlet end, and outlet passages having a closed inlet end and an open outlet end,
wherein the SCR catalyst composition comprises a zeolite and a base metal component, and
wherein the SCR catalyst composition permeates the walls at a concentration of at least 1.3 g/in3.

### Claim 2 (depends on 1)

The emission treatment system according to claim 1, further comprising an injector in fluid communication with and downstream of the oxidation catalyst, wherein the injector is capable of periodically metering reductant to the system.

### Claim 3 (depends on 1)

The emission treatment system according to claim 1, wherein the soot filter is capable of converting at least 50% of the NOx component to N2.

### Claim 4 (depends on 1)

The emission treatment system according to claim 1, wherein the SCR catalyst composition permeates the walls at a concentration of 1.6 to 2.4 g/in3.

### Claim 5 (depends on 1)

The emission treatment system according to claim 1, wherein the walls have a porosity of from 55 to 75% and an average pore size of from 10 to 30 microns.

### Claim 6 (depends on 1)

The emission treatment system according to claim 1, wherein the wall flow monolith has from about 100 to 400 cells per square inch and a wall thickness between 0.002 and 0.015 inches.

### Claim 7 (depends on 1)

The emission treatment system according to claim 1, wherein the wall flow monolith comprises silicon carbide.

### Claim 8 (depends on 1)

The emission treatment system according to claim 1, wherein the base metal component comprises copper.

### Claim 9 (depends on 1)

The emission treatment system according to claim 1, wherein the zeolite has a silica to alumina ratio of at least 10.

### Claim 10 (depends on 1)

The emission treatment system according to claim 1, wherein the oxidation catalyst is effective to convert at least 20% of NO of the NOx component to NO2.

### Claim 11 (depends on 1)

The emission treatment system according to claim 1, wherein the oxidation catalyst is effective to convert between 30 and 60% of NO of the NOx component to NO2.

### Claim 12 (depends on 1)

The emission treatment system according to claim 1, wherein the oxidation catalyst comprises a platinum group metal component.

### Claim 13 (depends on 12)

The emission treatment system according to claim 12, wherein the oxidation catalyst further comprises a zeolite.

### Claim 14 (depends on 1)

The emission treatment system according to claim 1, wherein the SCR composition is present on the inlet sides of the walls, on the outlet sides of the walls, and also permeates the walls.

### Claim 15 (depends on 1)

The emission treatment system according to claim 1, wherein the wall flow monolith comprises a washcoat of the SCR catalyst composition.

### Claim 16 (depends on 1)

The emission treatment system according to claim 1, wherein the SCR catalyst composition has thermal resistance to temperatures greater than 650° C.

### Claim 17 (depends on 1)

The emission treatment system according to claim 1, wherein the SCR catalyst composition is effective to catalyze conversion of the NOx component to N2 in the presence of a reductant.

### Claim 18 (depends on 1)

The emission treatment system according to claim 1, wherein the pressure drop of flowing air under ambient conditions across the soot filter is not more than 25% higher than the same soot filter containing no catalyst composition.

### Claim 19 (depends on 1)

The emission treatment system according to claim 1, wherein the pressure drop of flowing air under ambient conditions across the soot filter is less than 20 kPa at an air flow of 300 cfm or less.

### Claim 20 (depends on 1)

The emission treatment system according to claim 1, wherein the soot filter is effective for removing greater than 80% of the particulate matter in the exhaust stream.

### Claim 21

A catalyst article in the form of a soot filter comprising a wall flow monolith and an SCR catalyst composition, wherein the wall flow monolith has a plurality of longitudinally extending passages formed by longitudinally extending walls bounding and defining said passages, wherein the passages comprise inlet passages having an open inlet end and a closed outlet end, and outlet passages having a closed inlet end and an open outlet end,
wherein the wall flow monolith comprises an SCR catalyst composition that permeates the walls at a concentration of at least 1.3 g/in3, wherein the SCR catalyst composition comprises a zeolite and a base metal component.

### Claim 22 (depends on 21)

The catalyst article according to claim 21, wherein the SCR catalyst composition permeates the walls at a concentration of 1.6 to 2.4 g/in3.

### Claim 23 (depends on 21)

The catalyst article according to claim 21, wherein the walls have a porosity of from 55 to 75% and an average pore size of from 10 to 30 microns.

### Claim 24 (depends on 21)

The catalyst article according to claim 21, wherein the wall flow monolith has from about 100 to 400 cells per square inch and a wall thickness between 0.002 and 0.015 inches.

### Claim 25 (depends on 21)

The catalyst article according to claim 21, wherein the wall flow monolith comprises silicon carbide.

### Claim 26 (depends on 21)

The catalyst article according to claim 21, wherein the base metal component comprises copper.

### Claim 27 (depends on 21)

The catalyst article according to claim 21, wherein the zeolite has a silica to alumina ratio of at least 10.

### Claim 28 (depends on 21)

The catalyst article according to claim 21, wherein the SCR catalyst composition is present on the inlet sides of the walls, on the outlet sides of the walls, and also permeates the walls.

### Claim 29 (depends on 21)

The catalyst article according to claim 21, wherein the wall flow monolith comprises a washcoat of the SCR catalyst composition.

### Claim 30 (depends on 21)

The catalyst article according to claim 21, wherein the pressure drop of flowing air under ambient conditions across the soot filter is not more than 25% higher than the same soot filter containing no catalyst composition.

### Claim 31 (depends on 21)

The catalyst article according to claim 21, wherein the pressure drop of flowing air under ambient conditions across the soot filter is less than 20 kPa at an air flow of 300 cfm or less.

### Claim 32 (depends on 21)

The catalyst article according to claim 21, wherein the soot filter is effective for removing greater than 80% of particulate matter in an exhaust stream.

### Claim 33 (depends on 21)

The catalyst article according to claim 21, where the SCR catalyst composition has thermal resistance to temperatures greater than 650° C.

### Claim 34 (depends on 21)

The catalyst article according to claim 21, wherein the SCR catalyst composition permeates the walls at a concentration of 1.6 to 2.4 g/in3, which walls have a porosity of from 55 to 75% and an average pore size of from 10 to 30 microns, wherein the wall flow monolith comprises silicon carbide and has from about 100 to 400 cells per square inch and a wall thickness between 0.002 and 0.015 inches, and wherein the SCR catalyst composition comprises a zeolite having a silica to alumina ratio of at least 10 and copper.

### Claim 35 (depends on 21)

The catalyst article according to claim 21, wherein the soot filter is capable of converting at least 50% of a NOx component in an exhaust stream to N2.