SCR CATALYST DEVICE CONTAINING VANADIUM OXIDE AND MOLECULAR SIEVE CONTAINING IRON

• US 20190314801A1
• Filed: 12/20/2017
• Published: 10/17/2019
• Est. Priority Date: 12/20/2016
• Status: Active Grant

• Current Assignee: Umicore AG & Company KG (Umicore S.A.)
• Original Assignee: Umicore AG & Company KG (Umicore S.A.)
• Inventors: MALMBERG, Stephan, SOEGER, Nicola
• Granted Patent: US 11,229,901 B2
• Time in Patent Office: Days
• CPC Class Codes: B01D 2251/2062 Ammonia
• CPC Class Codes: B01D 2251/2067 Urea
• CPC Class Codes: B01D 2255/2065 Cerium
• CPC Class Codes: B01D 2255/20707 Titanium
• CPC Class Codes: B01D 2255/20723 Vanadium
• CPC Class Codes: B01D 2255/20738 Iron
• CPC Class Codes: B01D 2255/20776 Tungsten
• CPC Class Codes: B01D 2255/50 Zeolites
• CPC Class Codes: B01D 2255/9022 Two layers
• CPC Class Codes: B01D 2255/9032 Two zones
• CPC Class Codes: B01D 2257/404 Nitrogen oxides other than dinitrogen oxide
• CPC Class Codes: B01D 53/9418 for removing nitrogen oxides by selective catalytic reduction [SCR] using a reducing agent in a lean exhaust gas
• CPC Class Codes: B01J 23/22 Vanadium
• CPC Class Codes: B01J 23/30 Tungsten
• CPC Class Codes: B01J 29/7615 Zeolite Beta
• CPC Class Codes: B01J 35/19 Catalysts containing parts with different compositions
• CPC Class Codes: B01J 35/56 Foraminous structures having flow-through passages or channels, e.g. grids or three-dimensional monoliths
• CPC Class Codes: B01J 37/0244 Coatings comprising several layers
• CPC Class Codes: F01N 2370/04 Zeolitic material
• CPC Class Codes: F01N 2610/02 the substance being ammonia or urea
• CPC Class Codes: F01N 3/2066 : Selective catalytic reduction [SCR]
• CPC Class Codes: F01N 3/2828 : Ceramic multi-channel monoliths, e.g. honeycombs
• CPC Class Codes: Y02A 50/20 : Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
• CPC Class Codes: Y02C 20/10 : of nitrous oxide (N2O)
• CPC Class Codes: Y02T 10/12 : Improving ICE efficiencies

Abstract

The invention relates to a catalyst device for purifying exhaust gases containing nitrogen oxide by means of selective catalytic reduction (SCR), comprising at least two catalytic regions, the first region containing vanadium oxide and cerium oxide, and the second region containing a molecular sieve containing iron. The invention also relates to uses, the catalyst device and methods for purifying exhaust gases.

Claims

1. Catalyst device for purifying exhaust gases containing nitrogen oxide by means of selective catalytic reduction (SCR), comprising at least two catalytic regions, the first region containing vanadium oxide and cerium oxide, and the second region containing a molecular sieve containing iron.

2. Catalyst device according to claim 1, wherein the first region contains at least one additional component selected from oxides of tungsten, titanium, silicon and aluminum.

3. Catalyst device according to claim 1, wherein the first region comprises from 0.2 to 10% by weight of cerium oxide, calculated as CeO₂ and based on the weight of the first region.

4. Catalyst device according to claim 1, wherein the first region comprises from 0.5 to 7% by weight of cerium oxide, calculated as CeO₂ and based on the weight of the first region.

5. Catalyst device according to claim 1, wherein the first region comprises from 0.5 to 3% by weight of cerium oxide, calculated as CeO₂ and based on the weight of the first region.

6. Catalyst device according to claim 1, wherein the first region comprises the following components:

(a) from 0.5 to 10% by weight vanadium oxide, calculated as V₂O₅,

(b) from 0.2 to 10% by weight cerium oxide, calculated as CeO₂,

(c) from 0 to 17% by weight tungsten oxide, calculated as WO₃,

(d) from 25 to 98% by weight titanium oxide, calculated as TiO₂,

(e) from 0 to 15% by weight silicon oxide, calculated as SiO₂,

(f) from 0 to 15% by weight aluminum oxide, calculated as Al₂O₃

and in each case based on the weight of the first region.

7. Catalyst device according to claim 1, wherein the molecular sieve is a zeolite.

8. Catalyst device according to claim 7, wherein the zeolite is an iron-exchanged zeolite that preferably has a structure whose maximum ring size has more than 8 tetrahedra.

9. Catalyst device of claim 7, wherein the zeolite has a structure selected from AEL, AFI, AFO, AFR, ATO, BEA, GME, HEU, MFI, MWW, EUO, FAU, FER, LTL, MAZ, MOR, MEL, MTW, OFF and TON.

10. Catalyst device according to claim 1, which is designed in such a manner that the exhaust gases initially contact the first region.

11. Catalyst device according to claim 10, wherein the first and second region form adjacent zones, wherein the first region is a first zone and the second region is a second zone, wherein the first zone is upstream of the second zone in the direction of flow of the exhaust gas.

12. Catalyst device according to claim 10, wherein the first and second region form superimposed layers, wherein the first region is the top layer.

13. Catalyst device according to claim 1, wherein the first and second region are applied onto an inert substrate that is preferably a ceramic monolith.

15. A method of selective catalytic reduction (SCR), comprising utilizing catalyst device according to claim 1 for purifying exhaust gases containing nitrogen oxide by means of selective catalytic reduction (SCR).

16. The method according to claim 15 wherein the method includes avoiding the formation of nitrous oxide.

17. The method according to claim 15, wherein the exhaust gases have an NO₂/NO_x ratio of >

0.5 and/or a temperature of 180°

C. to 450°

C.

18. Method for purifying exhaust gases, comprising the steps of:

(i) Providing a catalyst device or a system according to claim 1,

(ii) Introducing exhaust gases containing nitrogen oxides into the catalyst device,

(iii) Introducing a reducing agent containing nitrogen into the catalyst device, and

(iv) Reducing nitrogen oxides in the catalyst device by means of selective catalytic reduction (SCR).

14. System or device, comprising a catalyst device according to the invention and an upstream device releasing exhaust gases, in particular a combustion engine.