8-ring small pore molecular sieve as high temperature SCR catalyst

Patent metadata

Field	Value
Publication number	US-9302256-B2
Application number	US-201414536868-A
Country	US
Kind code	B2
Filing date	Nov 10, 2014
Priority date	Oct 19, 2012
Publication date	Apr 5, 2016
Grant date	Apr 5, 2016

Abstract

Described is a selective catalytic reduction catalyst comprising an iron-promoted 8-ring small pore molecular sieve. Systems and methods for using these iron-promoted 8-ring small molecular sieves as catalysts in a variety of processes such as abating pollutants in exhaust gases and conversion processes are also described.

First claim

What is claimed is:

1. A selective catalytic reduction catalyst comprising an 8-ring small pore molecular sieve promoted with greater than 5 wt. % iron so that the catalyst is effective to catalyze the selective catalytic reduction of nitrogen oxides in the presence of a reductant, wherein the 8-ring small pore molecular sieve has a silica to alumina ratio in the range of 10 and 100.

2. The catalyst of claim 1 , wherein the iron-promoted 8-ring small pore molecular sieve is selected from the group consisting of iron-promoted zeolite having a structure type selected from AEI, AFT, AFX, CHA, EAB, ERI, KFI, LEV, SAS, SAT, and SAV.

3. The catalyst of claim 2 , wherein the iron-promoted 8-ring small pore molecular sieve has the CHA crystal structure.

4. The catalyst of claim 3 , wherein the iron-promoted 8-ring small pore molecular sieve having the CHA crystal structure is selected from an aluminosilicate zeolite, a borosilicate, a gallosilicate, a SAPO, an ALPO, a MeAPSO, and a MeAPO.

5. The catalyst of claim 4 , wherein the iron-promoted 8-ring small pore molecular sieve is selected from the group consisting of SSZ-13, SSZ-62, natural chabazite, zeolite K-G, Linde D, Linde R, LZ-218, LZ-235, LZ-236, ZK-14, SAPO-34, SAPO-44, SAPO-47, and ZYT-6.

6. The catalyst of claim 3 , wherein the 8-ring small pore molecular sieve having the CHA structure is an aluminosilicate zeolite having the CHA crystal structure.

7. The catalyst of claim 6 , wherein the aluminosilicate zeolite having the CHA crystal structure is selected from iron-promoted SSZ-13 and iron-promoted SSZ-62.

8. The catalyst of claim 1 , wherein the 8-ring small pore molecular sieve has a silica to alumina ratio in the range of 15 and 50.

9. The catalyst of claim 1 , comprising iron in the range of 5.1 wt. % to 10 wt. %, calculated as Fe 2 O 3 .

10. The catalyst of claim 7 , comprising iron in the range of 5.1 wt. % to 10 wt. %, calculated as Fe 2 O 3 .

11. The catalyst of claim 8 , comprising iron in the range of 5.1 wt. % to 10 wt. %, calculated as Fe 2 O 3 .

12. A catalytic article comprising the catalyst of claim 1 in a washcoat deposited on a honeycomb substrate.

13. The catalytic article of claim 12 , wherein the honeycomb substrate comprises a wall flow filter substrate.

14. The catalytic article of claim 12 , wherein the honeycomb substrate comprises a flow through substrate.

15. An exhaust gas treatment system comprising the catalytic article of claim 12 disposed downstream from a diesel engine and an injector that adds a reductant to an exhaust gas stream from the engine.

16. A method for selectively reducing nitrogen oxides, the method comprising contacting a gaseous stream containing nitrogen oxides with a selective catalytic reduction catalyst comprising an 8-ring small pore molecular sieve promoted with greater than 5 wt. % iron to catalyze the selective catalytic reduction of the nitrogen oxides in the presence of a reductant, wherein the 8-ring small pore molecular sieve has a silica to alumina mole ratio in the range of about 10 to 100.

17. The method of claim 16 , wherein the 8-ring small pore molecular sieve promoted with iron is selected from the group consisting of AEI, AFT, AFX, CHA, EAB, ERI, KFI, LEV, SAS, SAT, and SAV.

18. The method of claim 17 , wherein the 8-ring small pore molecular sieve promoted with iron has the CHA crystal structure.

19. The method of claim 18 , wherein the 8-ring small pore molecular sieve promoted with iron and having the CHA crystal structure is selected from the group consisting of aluminosilicate zeolite, SAPO, ALPO and MeAPO.

20. The method of claim 19 , wherein the 8-ring small pore molecular sieve promoted with iron and having the CHA crystal structure is selected from the group consisting of SSZ-13, SSZ-62, natural chabazite, zeolite K-G, Linde D, Linde R, LZ-218, LZ-235, LZ-236, ZK-14, SAPO-34, SAPO-44, SAPO-47, and ZYT-6.

21. The method of claim 20 , wherein the 8-ring small pore molecular sieve promoted with iron and having the CHA crystal structure is an aluminosilicate zeolite.

22. The method of claim 21 , wherein the aluminosilicate zeolite is selected from SSZ-13 and SSZ-62.

Assignees

• Basf Corp
• N E Chemcat Corp
• Heesung Catalysts Corp
• N E Chemcat Corp

Inventors

• Mohanan Jaya L
• Burk Patrick
• Breen Michael
• Slawski Barbara
• Nagata Makoto
• Banno Yasuyuki
• Kim Eunseok

Classifications

• B01J29/76

  Iron group metals or copper · CPC title

• F01N3/2066

  Selective catalytic reduction [SCR] · CPC title

• B01J29/88

  Ferrosilicates; Ferroaluminosilicates {(B01J29/005 takes precedence)} · CPC title

• F01N2510/063

  zeolites · CPC title

• B01D2258/012

  Diesel engines and lean burn gasoline engines · CPC title