Vanadium trapping SCR system

Patent metadata

Field	Value
Publication number	US-10994267-B2
Application number	US-201616316781-A
Country	US
Kind code	B2
Filing date	Jul 14, 2016
Priority date	Jul 14, 2016
Publication date	May 4, 2021
Grant date	May 4, 2021

Abstract

The present invention is directed towards the use of an ion-exchanged zeolite containing ASC as a trap for volatile vanadium compounds in a downstream position of a vanadium containing SCR-catalyst.

First claim

The invention claimed is:

1. An NH 3 -SCR-system comprising a vanadium based upstream SCR-catalyst and a downstream ASC, with the ASC comprising a Cu- or Fe-exchanged BEA zeolite as a trap for volatile vanadium compounds, and wherein the ASC comprises platinum group metal and is designed such that the Cu- or Fe-exchanged BEA zeolite is positioned, at least to some extent, for contact with the exhaust gas with volatile vanadium compounds prior to exhaust contact with the platinum group metal of the ASC.

2. The NH 3 -SCR-system according to claim 1 , wherein the ASC is located in the same housing as the SCR-catalyst.

3. The NH 3 -SCR-system according to claim 1 , wherein the Cu- or Fe-exchanged BEA zeolite contains ion-exchanged and non-ion exchanged Cu or Fe-ions in a molar ratio of greater than 90:10.

4. The NH 3 -SCR-system according to claim 1 , wherein the Cu- or Fe-exchanged BEA zeolite is provided in a coating coated over an entire length of the ASC.

5. The NH 3 -SCR-system according to claim 4 , wherein the platinum group metal is provided in a noble metal layer and wherein the coating of Cu- or Fe-exchanged BEA zeolite extends over the noble metal layer as to provide for the prior contact with volatile vanadium compounds.

6. The NH 3 -SCR-system according to claim 5 wherein the platinum group metal in the noble metal layer comprises Pt.

7. The NH 3 -SCR-system according to claim 6 wherein the platinum group metal in the noble metal layer comprises only Pt.

8. The NH 3 -SCR-system according to claim 7 , wherein the noble metal layer is entirely covered over by the coating of Cu- or Fe-exchanged BEA zeolite.

9. The NH 3 -SCR-system according to claim 1 wherein the ASC is a coating of Fe-exchanged BEA zeolite.

10. The NH 3 -SCR-system according to claim 1 wherein the ASC is a coating of Cu-exchanged BEA zeolite.

11. A method of catalytic treatment of exhaust gas comprising passing exhaust gas through the NH 3 -SCR-system of claim 1 .

12. The method of claim 11 wherein the exhaust gas is diesel exhaust gas and the diesel exhaust gas at an outlet of the NH 3 -SCR-system has a measured zero ppm Vanadium concentration at 475° C. exhaust gas temperature level as measured at an exit point of the vanadium based upstream SCR-catalyst.

13. A method of assembling the NH 3 -SCR-system of claim 1 comprising positioning each of the vanadium based upstream SCR-catalyst and the downstream ASC within an exhaust passageway.

14. An NH 3 -SCR-system comprising a first and a second vanadium based SCR-catalyst and an ASC positioned downstream of both the first and second vanadium based SCR-catalysts, with the ASC comprising a Cu- or Fe-exchanged BEA zeolite as a trap for volatile vanadium compounds, and wherein the ASC comprises platinum group metal and is designed such that the Cu- or Fe-exchanged BEA zeolite is positioned, at least to some extent, for contact with exhaust gas with volatile vanadium compounds prior to exhaust gas contact with the platinum group metal of the ASC.

15. The NH 3 -SCR-system according to claim 1 , wherein the Cu- or Fe-exchanged BEA zeolite is positioned so as to entirely come in first contact with the exhaust gas with volatile vanadium prior to exhaust gas contact with the platinum group metal.

16. The NH 3 -SCR-system according to claim 1 wherein the platinum group metal is in an amount of 3 to 7 g/ft 3 .

17. The NH 3 -SCR-system according to claim 1 wherein the Cu- or Fe-exchanged BEA zeolite is in a continuous layer above a layer containing the platinum group metal such that the Cu- or Fe-exchanged BEA zeolite entirely comes in first contact with the exhaust gas with volatile vanadium prior to exhaust gas contact with the platinum group metal.

18. The NH 3 -SCR-system according to claim 1 wherein the vanadium based upstream SCR-catalyst and the downstream ASC are provided on a common brick.

19. An NH 3 -SCR-system comprising a vanadium based upstream SCR-catalyst and a downstream ASC, with the ASC comprising a Cu- or Fe-exchanged large pore zeolite as a trap for volatile vanadium compounds, and wherein the ASC comprises platinum group metal and is designed such that the Cu- or Fe-exchanged large pore zeolite is provided in a layer overlying a layer containing the platinum group metal.

20. The NH 3 -SCR-system according to claim 19 wherein the large pore zeolite is BEA.

21. The NH 3 -SCR-system according to claim 1 wherein Cu- or Fe-exchanged BEA zeolite is the sole zeolite of the ASC.

22. The NH 3 -SCR-system according to claim 1 wherein the platinum group metal is in an amount of 2 to 10 g/ft 3 .

Assignees

• Umicore Ag & Co Kg

Inventors

• Duisberg Matthias
• Ristori Alain
• Malmberg Stephan
• Pfeifer Marcus

Classifications

• B01J23/44

  Palladium · CPC title

• F01N3/106

  Auxiliary oxidation catalysts · CPC title

• B01J29/76

  Iron group metals or copper · CPC title

• B01J37/0246

  Coatings comprising a zeolite · CPC title

• B01D53/9436

  Ammonia · CPC title