Active SCR catalyst

Patent metadata

Field	Value
Publication number	US-11014077-B2
Application number	US-201716096126-A
Country	US
Kind code	B2
Filing date	May 2, 2017
Priority date	May 3, 2016
Publication date	May 25, 2021
Grant date	May 25, 2021

Abstract

The invention relates to a catalyst comprising a small-pore zeolite that contains iron and copper and has a maximum ring size of eight tetrahedral atoms, characterized in that the channel width of the small-pore zeolite amounts to >3.8 Å (0.38 nm) in at least one dimension.

First claim

The invention claimed is:

1. A catalyst comprising a small-pore zeolite that contains iron and copper and has a maximum ring size of eight tetrahedral atoms, wherein the small-pore zeolite has a structure of type EAB, ERI, ESV, JBW or LEV, and wherein a channel width of the small-pore zeolite amounts to ≥0.47 nm (4.7 Å) in at least one dimension, and wherein the small-pore zeolite comprises copper in an amount of 1.0 to 1.9 wt. %, calculated as Cu, and iron in an amount of 1.0 to 2.0 wt. %, calculated as Fe, based in each case on the total weight of the small-pore zeolite with the copper and iron, and wherein the small pore zeolite contains no further metal besides copper and iron.

2. A catalyst comprising a small-pore zeolite that contains iron and copper and has a maximum ring size of eight tetrahedral atoms, wherein the small-pore zeolite has a structure type of EAB, ERI, ESV, JBW or LEV, and wherein a channel width of the small-pore zeolite amounts to >0.38 nm (3.8 Å) in at least one dimension, and wherein the small-pore zeolite comprises copper in an amount of 1.5 wt. %, calculated as Cu, and iron in an amount of 1.3 wt. %, calculated as Fe, based in each case on the total weight of the small-pore zeolite with the copper and iron, and wherein the small pore zeolite contains no further metal besides copper and iron.

3. The catalyst according to claim 1 , wherein the small-pore zeolite is of the structure type ERI or LEV.

4. The catalyst according to claim 1 , wherein the small-pore zeolite has a SAR value of 1 to 50.

5. The catalyst according to claim 1 , wherein the small-pore zeolite is of the structure type ERI and has an SAR value of 5 to 15.

6. The catalyst according to claim 2 , wherein the molar ratio of Cu:Al is 0.03 to 0.10.

7. The catalyst according to claim 2 , wherein the molar ratio of (Cu+Fe):Al is 0.12 to 0.2.

8. The catalyst according to claim 1 , wherein the small-pore zeolite is of the structure type LEV and has a SAR value of 20 to 40.

9. The catalyst according to claim 8 , wherein a molar ratio of Cu:Al is 0.15 to 0.30.

10. The catalyst according to claim 8 , wherein a molar ratio of (Cu+Fe):A1 is 0.32 to 0.50.

11. The catalyst according to claim 1 , wherein the catalyst is present in a form of a coating on a carrier substrate.

12. The catalyst according to claim 11 , wherein the carrier substrate is a flow-through substrate or a wall-flow filter.

13. The catalyst according to claim 11 , wherein the carrier substrate is inert and consists of silicon carbide, aluminum titanate or cordierite.

14. The catalyst according to claim 11 , wherein the carrier substrate comprises a catalytically active material.

15. The catalyst according to claim 14 , wherein the carrier substrate comprises an SCR catalytically active material.

16. The catalyst according to claim 14 , wherein the catalytically active material comprises a mixed oxide containing vanadium, titanium and tungsten compounds.

17. The catalyst according to claim 1 , wherein the catalyst is present as part of a carrier substrate.

18. The catalyst according to claim 17 , wherein the carrier substrate is a flow-through substrate or a wall-flow filter.

19. The catalyst according to claim 17 , wherein the carrier substrate is coated with a catalytically active material.

20. The catalyst according to claim 2 , wherein the channel width of the small-pore zeolite is ≥0.47 nm (4.7 A) in at least one dimension.

21. A method for purifying exhaust gas of lean-operated combustion engines, wherein the exhaust gas is passed over a catalyst according to claim 1 .

22. A system for purifying exhaust gas from lean-operated combustion engines, wherein the system comprises the catalyst according to claim 1 as well as an injector for aqueous urea solution, wherein the injector is located upstream of the catalyst.

23. The system according to claim 22 , wherein the system further comprises an oxidation catalyst.

24. The system according to claim 23 , wherein the oxidation catalyst includes platinum.

25. A catalyst comprising a small-pore zeolite that contains iron and copper and has a maximum ring size of eight tetrahedral atoms, and wherein the small-pore zeolite comprises copper in an amount of 1.0 to 1.9 wt. %, calculated as Cu and iron in an amount of 1.0 to 2.0 wt. %, calculated as Fe, based in each case on the total weight of the small-pore zeolite with the copper and iron, and wherein the small pore zeolite contains no further metal besides copper and iron, wherein the small-pore zeolite has either a structure type of ERI with an SAR value of 5 to 15, or a structure type of LEV with an SAR value of 20 to 40, and wherein a channel width of the small-pore zeolite is 0.48 to 0.51 nm in at least one dimension.

Assignees

• Umicore Ag & Co Kg

Inventors

• Wen Fei
• Soeger Nicola
• GIESHOFF JüRGEN

Classifications

• B01J35/56

  Foraminous structures having flow-through passages or channels, e.g. grids or three-dimensional [3D] monoliths · CPC title

• B01J29/58

  containing arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium · CPC title

• B01J29/78

  containing arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium · CPC title

• F01N3/208

  Control of selective catalytic reduction [SCR], e.g. by adjusting the dosing of reducing agent · CPC title

• B01D53/9413

  Processes characterised by a specific catalyst · CPC title