Catalytic Article for Treating Exhaust Gas

Patent metadata

Field	Value
Publication number	US-2016008759-A1
Application number	US-201514713453-A
Country	US
Kind code	A1
Filing date	May 15, 2015
Priority date	May 16, 2014
Publication date	Jan 14, 2016
Grant date	—

Abstract

Provided is a catalytic article comprising (a) a flow through honeycomb substrate having channel walls; (b) a first NH 3 -SCR catalyst composition coated on and/or within the channel walls in a first zone; and (c) a second NH 3 -SCR catalyst composition coated on and/or within the channel walls in a second zone, provided that the first zone is upstream of the second zone and the first and second zones are adjacent or at least partially overlap; and wherein the first NH 3 -SCR catalyst comprises a first copper loaded molecular sieve having a copper to aluminum atomic ratio of about 0.1 to 0.375 and the second NH 3 -SCR catalyst comprises a second copper loaded molecular sieve having a copper-to-aluminum atomic ratio of about 0.3 to about 0.6.

First claim

What is claimed is:

1 . A catalytic article comprising:
a. a flow through honeycomb substrate having an inlet side, an outlet side, an axial length from the inlet side to the outlet side, and a plurality of channels defined by channel walls extending from the inlet side to the outlet side; b. a first NH 3 -SCR catalyst composition coated on and/or within the channel walls in a first zone; and c. a second NH 3 -SCR catalyst composition coated on and/or within the channel walls in a second zone, provided that the first zone is upstream of the second zone and the first and second zones are adjacent or at least partially overlap;
wherein the first NH 3 -SCR catalyst comprises a first copper loaded molecular sieve having a copper to aluminum atomic ratio of about 0.1 to 0.375 and the second NH 3 -SCR catalyst comprises a second copper loaded molecular sieve having a copper-to-aluminum atomic ratio of about 0.3 to about 0.6.

2 . The catalytic article of claim 1 , wherein the first zone is adjacent to the second zone.

3 . The catalytic article of claim 1 , wherein the first zone completely overlays the second zone.

4 . The catalytic article of claim 1 , wherein first zone extends from the inlet side to a first end point that is position about 10 to 40 percent of the axial length and wherein the second zone is about 20 to 90 percent of the axial length, provided that the first and second zones are adjacent or overlap by less than 90 percent of the axial length.

5 . The catalytic article of claim 4 , wherein the first zone overlaps the second zone.

6 . The catalytic article of claim 4 , wherein the second zone overlaps the first zone.

7 . The catalytic article of claim 1 , wherein the first copper loaded molecular sieve has a lower copper concentration relative to the second copper loaded molecular sieve.

8 . The catalyst article of claim 2 , wherein the first copper loaded molecular sieve has a copper loading of about 50 to 90 percent of second copper loaded molecular sieve.

9 . The catalytic article of claim 1 , wherein the first copper loaded molecular sieve has a first SAR and the second copper loaded molecular sieve has a second SAR which is larger than the first SAR.

10 . The catalyst article of claim 9 , wherein the first molecular sieve is an aluminosilicate having a SAR of about 10 to about 20 and the second molecular sieve is an aluminosilicate having a SAR of about 20 to about 50.

11 . The catalyst article of claim 9 , wherein the first and second molecular sieves have a small pore framework.

12 . The catalyst article of claim 9 , wherein the first and second molecular sieves have a CHA framework.

13 . The catalyst article of claim 9 , wherein the first molecular sieve is a silicoaluminophosphate and the second molecular sieve is an aluminosilicate having a SAR of about 15 to about 50.

14 . The catalyst article of claim 4 , wherein the first and second zones overlap to create a third catalyst zone, wherein the third zone having a higher amount of copper compared to the first and second zones, individually.

15 . The catalyst article of claim 1 , further comprising an ASC zone having an ammonia oxidation catalyst coated on and/or within the channel walls, wherein the ASC zone extends from the outlet side for a distance that is about 10 to 50 percent of the axial length and does not contact the first zone.

16 . The catalyst article of claim 15 , wherein the second NH 3 -SCR catalyst composition fully overlaps the oxidation catalyst.

17 . The catalyst article of claim 16 , wherein the oxidation catalyst comprises platinum.

18 . A catalyst article comprising:
a. a flow through honeycomb substrate having an inlet side, an outlet side, an axial length from the inlet side to the outlet side, and a plurality of channels defined by channel walls extending from the inlet side to the outlet side, b. a first catalytic zone consisting of a first washcoat, c. a second catalytic zone consisting of the first washcoat and a second washcoat, d. a third catalytic zone consisting of the second washcoat, and e. a fourth catalytic zone consisting of the second washcoat over a third washcoat,
wherein the first washcoat contains a first copper loaded molecular sieve, the second washcoat contains a second copper loaded molecular sieve wherein the first and second molecular sieves are different materials, and the third washcoat contains an ammonia oxidation catalyst, and
wherein the first, second, third, and fourth zones are arranged in series on the substrate, each zone is adjacent to the next zone in the series, the first zone is proximal to the inlet side, and the fourth zone is proximal to the outlet side.

19 . A system for treating an exhaust gas comprising:
a. a catalytic article according to claim 1 ; and b. one or more exhaust gas treatment components selected from DOC, NAC, external NH 3 injector, secondary SCR catalyst, ASC, and particulate filter,
wherein the catalytic article according to claim 1 and the one or more exhaust gas treatment components are in fluid communication and are in series.

20 . A method for treating an exhaust gas comprising:
contacting an exhaust gas comprising NO x and NH 3 with a catalytic article according to claim 1 ; selectively reducing at least a portion of the NO x to N 2 and H 2 O.

Assignees

• Johnson Matthey Plc

Inventors

• Sonntag Olivier
• Genschow Tim
• Smedler Gudmund
• Walker Andrew Peter
• Larsson Mikael
• Markatou Penelope
• Zhang Lingzhi
• Gast Jane

Classifications

• B01D53/9418 Primary

  for removing nitrogen oxides by selective catalytic reduction [SCR] using a reducing agent in a lean exhaust gas · CPC title

• B01J29/763

  CHA-type, e.g. Chabazite, LZ-218 · CPC title

• B01D53/56

  Nitrogen oxides (B01D53/60 takes precedence) · CPC title

• B01D2255/9037

  More than three zones · CPC title

• B01D2255/50

  Zeolites · CPC title