Non-PGM ammonia slip catalyst

Patent metadata

Field	Value
Publication number	US-11198094-B2
Application number	US-201514726924-A
Country	US
Kind code	B2
Filing date	Jun 1, 2015
Priority date	Jun 4, 2014
Publication date	Dec 14, 2021
Grant date	Dec 14, 2021

Abstract

An ammonia slip catalyst having an SCR catalyst and an oxidation catalyst comprising at least two metals, each of which is selected from a specific group, and a substrate upon which at least oxidation catalyst is located is described. The ammonia slip catalyst can have dual layers, with one of the layers containing an SCR catalyst, a second layer containing the oxidation catalyst with comprises at least two metals, each of which is selected from a specific group, and the ammonia slip catalyst does not contain a platinum group metal. Methods of making and using the ammonia slip catalyst to reduce ammonia slip are described.

First claim

What is claimed is:

1. A dual layer ammonia slip catalyst comprising an SCR layer and an oxidation layer, wherein at least the oxidation layer is positioned proximal to a substrate, wherein
the SCR layer comprises a molecular sieve or a vanadium/titania SCR catalyst; and
the oxidation layer consists of:
(a) an ammonia oxidation catalyst consisting of copper and manganese; and
(b) an oxide support material consisting of alumina and either a CeO 2 /ZrO 2 mixed oxide or a Zr-stabilized CeO 2 mixed oxide;

wherein the ammonia slip catalyst does not comprise a platinum group metal.

2. The dual layer ammonia slip catalyst of claim 1 , wherein the oxidation layer further comprises an oxide support material comprising one or both of alumina and silica.

3. A method for reducing the concentration of ammonia in a flue gas stream generated by a combustion source, the method comprising contacting a flue gas stream containing ammonia with a dual layer ammonia slip catalyst of claim 1 .

4. The dual layer ammonia slip catalyst of claim 1 , wherein the substrate is a flow-through substrate.

5. The dual layer ammonia slip catalyst of claim 1 , wherein the Zr-stabilized CeO 2 mixed oxide comprises Ce and Zr present in about a 1:1 mole ratio.

6. The dual layer ammonia slip catalyst of claim 1 , wherein the oxide support material comprises about 20 mole % La-stabilized Al 2 O 3 and about 80 mole % Zr-stabilized CeO 2 .

7. The dual layer ammonia slip catalyst of claim 1 , wherein the molecular sieve is selected from the group consisting of MOR (mordenite), FER (ferrierite), FAU (zeolite Y), MFI (ZSM-5), BEA (beta zeolites), Fe-BEA, CHA (Chabazite), Cu-CHA and a silicoaluminophosphate comprising a structurally similar framework.

8. The dual layer ammonia slip catalyst of claim 7 , wherein the SCR layer comprises a Fe-BEA or a Cu-CHA zeolite catalyst or a silicoaluminophosphate comprising a structurally similar framework.

9. The dual layer ammonia slip catalyst of claim 8 , wherein the SCR layer comprises a Fe-BEA or a Cu-CHA zeolite or a silicoaluminophosphate comprising a structurally similar framework catalyst and the oxidation layer comprises Cu and Mn.

10. The dual layer ammonia slip catalyst of claim 1 , wherein the catalyst in the oxidation layer is present at a concentration of 0.3 to 1.5 g per in 3 , based on the total weight of metal in the catalyst.

11. The dual layer ammonia slip catalyst of claim 1 , wherein the catalyst in the SCR layer is present at a concentration of 0.5 to 2.5 g per in 3 , based on the total weight of metal in the catalyst.

12. The dual layer ammonia slip catalyst of claim 1 , wherein the ratio of the amount of catalyst in the SCR layer (in g per in 3 ) to the amount of catalyst in the oxidation layer (in g per in 3 ) is between 0.3 and 8.3, based on the total weight of metal in each layer of the catalyst.

13. The dual layer ammonia slip catalyst of claim 1 , wherein the SCR layer is positioned as an overlayer over the oxidation layer or the oxidation layer is located sequential to the SCR layer.

Assignees

• Johnson Matthey Plc

Inventors

• Andersen Paul Joseph
• Doura Kevin

Classifications

• B01J29/763

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

• B01J29/68

  Iron group metals or copper · CPC title

• B01J29/46

  Iron group metals or copper · CPC title

• B01J29/24

  Iron group metals or copper · CPC title

• B01J29/14

  Iron group metals or copper · CPC title