High temperature combustion catalyst

Patent metadata

Field	Value
Publication number	US-9694347-B2
Application number	US-201314385664-A
Country	US
Kind code	B2
Filing date	Mar 25, 2013
Priority date	Apr 4, 2012
Publication date	Jul 4, 2017
Grant date	Jul 4, 2017

Abstract

A supported precious metal catalyst for the high-temperature combustion of a hydrocarbon includes 1-10% by weight in total of one or more precious metals on a refractory metal oxide support material, and 1-20% by weight in total of one or more stabilizing metals selected from rare earths and Groups IA, IIA, and IIIA of the periodic table of the elements, wherein at least part of the precious metal is present as a mixed metal oxide with one or more of the stabilizing metals.

First claim

The invention claimed is:

1. A supported precious metal catalyst for the high-temperature combustion of a hydrocarbon comprising 1-10% by weight in total of precious metals on a refractory metal oxide support material, further comprising 1-20% by weight in total of one or more stabilizing metals selected from rare earths and Groups IA, IIA, and IIIA of the periodic table of the elements, wherein the precious metals comprises platinum and palladium, at least part of the platinum and/or palladium is present as a mixed metal oxide with one or more of said stabilizing metals, and the weight ratio of palladium to platinum is 1:10 to 10:1.

2. A catalyst according to claim 1 wherein the total precious metal content is in the range 5-10% by weight.

3. A catalyst according to claim 1 wherein the weight ratio of palladium to platinum is 1:2 to 10:1.

4. A catalyst according to claim 1 wherein the refractory metal oxide support material is selected from the group consisting of alumina, zirconia, titania, silica, tin oxide and mixtures thereof.

5. A catalyst according to claim 1 wherein the stabilizing metal comprises one or more of lithium, sodium, potassium, magnesium, calcium, strontium, barium, scandium, yttrium, lanthanum and cerium.

6. A catalyst according to claim 1 wherein the stabilizing metal comprises calcium.

7. A catalyst according to claim 6 wherein the calcium content of the catalyst is in the range 1-10%, by weight on the refractory metal oxide support.

8. A catalyst according to claim 6 wherein the mixed metal oxide comprises CaM 3 O 4 in which M is Pd and/or Pt.

9. A catalyst according to claim 6 wherein the calcium content of the catalyst is in the range 2.5-7.5% by weight on the refractory metal oxide support.

10. A catalyst according to claim 1 wherein the refractory metal oxide support material is a powder.

11. A method for preparing a catalyst according to claim 1 wherein the precious metal comprises platinum and palladium and the weight ratio of palladium to platinum is 1:10 to 10:1, comprising the steps of separately impregnating a refractory metal oxide with a solution of a stabilizing metal and a solution of the precious metals in either order, with first and second calcination steps following each of said impregnations, wherein the first calcination step is performed at a maximum temperature in the range 400-600° C. and the second calcination step performed at a maximum temperature in the range 600-950° C.

12. A method according to claim 11 comprising the steps of (i) impregnating a refractory metal oxide support with a solution of the precious metals, drying and calcining the impregnated support in a first calcination step to form an un-modified catalyst and (ii) impregnating the unmodified catalyst with a solution of the stabilizing metal, drying and calcining the impregnated catalyst in a second calcination step to form the modified catalyst, wherein the first calcination step is performed at a maximum temperature in the range 400-600° C. and the second calcination step performed at a maximum temperature in the range 600-950° C.

13. A method according to claim 11 comprising the steps of (i) impregnating the refractory metal oxide with a solution of the stabilizing metal, and drying and calcining the impregnated support in a first calcination step at a maximum temperature in the range 400-600° C. to form a modified support material, and (ii) impregnating the modified support material with a solution of the precious metals, and drying and calcining the impregnated modified support in a second calcination step at a maximum temperature in the range 600-950° C.

14. A method according to claim 11 wherein the second calcination step is performed at a maximum temperature in the range 750-850° C.

15. A method according to claim 11 wherein the second calcination step comprises a pre-calcination step at a maximum temperature in the range 400-600° C.

16. A method according to claim 11 wherein the calcination is performed in air comprising steam in an amount in the range 1-20% by volume.

17. A method according to claim 11 wherein the refractory metal oxide support material is a powder and the resulting catalyst powder is applied as a wash-coat onto a metal or ceramic catalyst support.

18. A catalyst according to claim 1 wherein the mixed metal oxide further comprises one or more Pt/Pd alloys.

19. A catalyst according to claim 1 wherein the weight ratio of palladium to platinum is 1:2 to 2:1.

20. A catalyst according to claim 1 wherein the weight ratio of palladium to platinum is about 1:1.

21. A reactor for the high-temperature combustion of a hydrocarbon comprising a plurality of substantially parallel reaction channels, wherein at least one channel is provided with a supported precious metal catalyst for the high-temperature combustion of a hydrocarbon comprising 1-10% by weight in total of precious metals on a refractory metal oxide support material, further comprising 1-20% by weight in total of one or more stabilizing metals selected from rare earths and Groups IA, IIA, and IIIA of the periodic table of the elements, wherein the precious metal comprises platinum and palladium and at least part of the platinum and/or palladium is present as a mixed metal oxide with one or more of said stabilizing metals, and the weight ratio of palladium to platinum is 1:10 to 10:1.

22. A reactor according to claim 21 , wherein the catalyst is supported on a removable structure.

23. A reactor according to claim 21 , wherein the removable structure is a foil.

24. A reactor according to claim 21 , wherein each channel is defined by one or more walls and wherein the catalyst is provided on the walls.

25. A reactor according to claim 21 , wherein the catalyst is in the form of a powder, pellet or particle.

26. A reactor according to claim 21 , wherein at least one channel that is not provided with the precious metal catalyst, is provided with a catalyst for an endothermic reaction.

27. A reactor according to claim 26 , wherein the endothermic reaction is steam methane reforming.

28. A reactor according to claim 27 , wherein the catalyst for steam methane reforming is provided in alternate channels and the precious metal catalyst is provided in the remaining channels.

29. A reactor according to claim 21 , wherein each channel has at least one dimension less than 10 mm.

30. A process for the high temperature combustion of a hydrocarbon, comprising contacting a gaseous mixture of a hydrocarbon and an oxygen-containing gas with a catalyst according to claim 1 wherein the precious metal comprises platinum and palladium and the weight ratio of palladium to platinum is 1:10 to 10:1.

31. A process according to claim 30 wherein the hydrocarbon includes one or more aliphatic and aromatic hydrocarbons in the gaseous state.

32. A process according to claim 30 wherein the hydrocarbon includes methane and the methane content of the gas mixture fed to the catalyst is in the range 0.01 to 20% by volume.

33. A process according to claim 30 wherein the oxygen-containing gas is oxygen, oxygen-enriched air or air.

34. A process according to claim 30 wherein the mixture of hydrocarbon and oxygen is preheated to a pre-heat temperature in the range 650-950° C.

Assignees

• Johnson Matthey Plc

Inventors

• Cortes Felix Noelia Montserrat
• Scullard Andrew Charles

Classifications

• B01J23/58

  with alkali- or alkaline earth metals · CPC title

• B01D2255/1021

  Platinum · CPC title

• B01D53/864

  Removing carbon monoxide or hydrocarbons · CPC title

• B01J37/038

  to form slurries or suspensions, e.g. a washcoat · CPC title

• B01J23/42 Primary

  Platinum · CPC title