Catalyst gauze

Patent metadata

Field	Value
Publication number	US-12128392-B2
Application number	US-202017594237-A
Country	US
Kind code	B2
Filing date	May 20, 2020
Priority date	May 22, 2019
Publication date	Oct 29, 2024
Grant date	Oct 29, 2024

Abstract

A catalyst gauze and gauze pack comprise a knitted catalyst gauze containing a first layer of a first wire material, wherein the first wire material is made from a platinum-rhodium alloy, and wherein the first layer contains an activator in the form of a second wire material which is knitted among the first wire material, and which is made from un-alloyed platinum.

First claim

The invention claimed is:

1. A catalyst gauze pack for the catalytic oxidation of ammonia to nitric oxide, comprising a top layer consisting of a single activated catalyst gauze on a layer formed from one or more knitted gauzes made from a platinum-rich wire material comprising at least 85% by weight Pt, wherein the single activated catalyst gauze contains a first layer of knitted first wire material, wherein said first wire material is made from a platinum-rhodium alloy, and wherein said first layer contains an activator in the form of a second wire material which is knitted among the first wire material and which is made from un-alloyed platinum.

2. The catalyst gauze pack according to claim 1 wherein one or more knitted gauzes of a Pd—Pt alloy are placed below the one or more knitted gauzes made from the platinum-rich wire material to reduce nitrous oxide by-product formation.

3. The catalyst gauze pack according to claim 1 , further comprising a catchment layer comprising one or more catchment gauzes of palladium or a palladium-rich alloy as a bottom layer.

4. A process for the catalytic oxidation of ammonia comprising the steps of: (i) heating the catalyst gauze pack according to claim 1 to a temperature≥250° C., and (ii) passing a gas mixture comprising ammonia and air across the catalyst gauze pack to initiate ammonia oxidation.

5. The process according to claim 4 wherein the heating is performed by the combustion of hydrogen.

6. The process according to claim 4 , further comprising converting the nitric oxide to nitric acid.

7. A process for the catalytic oxidation of ammonia comprising the steps of: (i) heating the catalyst gauze pack according to claim 1 to a temperature≥250° C., and (ii) passing a gas mixture comprising ammonia and air and methane across the catalyst gauze pack to initiate ammonia oxidation.

8. The catalyst gauze pack according to claim 1 , wherein the first wire material is made from a Pt—Rh alloy with 1 to 10% by weight Rh.

9. The catalyst gauze pack according to claim 1 , wherein the second wire material is made from ≥99.5% by weight Pt.

10. The catalyst gauze pack according to claim 1 wherein the weight percentage of the activator second wire material in the catalyst gauze is in the range of 1 to 45% by weight.

11. The catalyst gauze pack according to claim 1 , wherein the weight percentage of the activator second wire material in the catalyst gauze is in the range of 1 to 33% by weight.

12. The catalyst gauze pack according to claim 1 , wherein the weight percentage of the activator second wire material in the catalyst gauze is in the range of 8 to 35% by weight.

Assignees

• Johnson Matthey Plc

Inventors

• Alibhai Asgar Mohamed Hussein
• Goddin Helen Theresa

Classifications

• C01B21/265

  characterised by the catalyst · CPC title

• B01J23/464

  Rhodium · CPC title

• B01J23/42

  Platinum · CPC title

• D10B2403/0242

  enhancing chemical properties · CPC title

• D10B2101/20

  Metallic fibres · CPC title