Catalyst bed and method for reducing nitrogen oxides

Patent metadata

Field	Value
Publication number	US-11020732-B2
Application number	US-201616064240-A
Country	US
Kind code	B2
Filing date	Dec 20, 2016
Priority date	Dec 22, 2015
Publication date	Jun 1, 2021
Grant date	Jun 1, 2021

Abstract

A catalyst bed comprising a ceramic or metallic foam comprising one or more NOx reduction catalysts is described. A method for reducing the concentration of NOx in a dust containing gas stream comprising: a) passing a first gas stream containing NOx into a contacting zone; b) contacting the first gas stream with a ceramic or metallic foam catalyst bed having one or more flow paths through the catalyst bed wherein the ceramic or metallic foam comprises a NOx reduction catalyst to produce a second gas stream with a reduced NOx concentration; and c) passing the second gas stream out of the contacting zone wherein the first gas stream has a dust concentration of at least 5 mg/Nm3 and the pressure drop of the foam catalyst bed increases by 300% or less relative to the initial pressure drop of the foam catalyst bed due to dust accumulation, measured under the same conditions is also described.

First claim

That which is claimed is:

1. A method for reducing a concentration of NO in a dust containing gas stream comprising:
a. passing a first gas stream containing NO into a contacting zone;
b. contacting the first gas stream with a catalyst bed having one or more flow paths through the catalyst bed, wherein the catalyst bed comprises a ceramic or metal foam catalyst having a NO x reduction catalyst configured to produce a second gas stream with a reduced NO x concentration, and wherein the NO x reduction catalyst comprises a bimodal pore distribution with more than 90% of a pore volume present in pores having a diameter of at most about 100 nanometers (nm); and
c. passing the second gas stream out of the contacting zone, wherein the first gas stream has a dust concentration of at least 5 mg/Nm 3 and a pressure drop of the catalyst bed increases by 300% or less relative to an initial pressure drop of the catalyst bed due to dust accumulation, measured under the same conditions.

2. The method of claim 1 , wherein the first gas stream has a dust concentration of at least 10 mg/Nm 3 .

3. The method of claim 1 , wherein the pressure drop of the catalyst bed increases by 200% or less relative to the initial pressure drop of the catalyst bed due to dust accumulation, measured under the same conditions.

4. The method of claim 1 , wherein the contacting occurs at a temperature in the range of from 100 to 250° C.

5. The method of claim 1 , wherein the ceramic or metallic foam catalyst has in the range of from about 5 to about 50 pores per inch.

6. The method of claim 1 , wherein the ceramic or metallic foam catalyst has an interconnected internal tortuous pore structure providing flow paths through the catalyst bed that have a tortuosity of greater than 1.0.

7. The method of claim 1 , wherein the ceramic foam catalyst comprises cordierite, titanium oxide or alumina.

8. The method of claim 1 , wherein the metallic foam catalyst comprises nickel, iron or alloys thereof.

9. The method of claim 1 , wherein the NO x reduction catalyst comprises vanadium, molybdenum, tungsten or mixtures thereof.

10. The method of claim 1 , wherein the ceramic or metallic foam catalyst further comprises a binder material.

11. The method of claim 1 , wherein the second gas stream comprises at least 50% of an amount of dust in the first gas stream.

12. The method of claim 1 , wherein the second gas stream comprises at least 80% of an amount of dust in the first gas stream.

13. The method of claim 1 , wherein a density range of the ceramic or metallic foam catalyst is between 0.4 to 0.75 grams/cubic centimeter (g/cm 3 ).

14. The method of claim 1 , wherein the contacting occurs at a pressure range of from 0 kilopascals (kPa) to 1200 kPa.

15. The method of claim 1 , wherein the NO x reduction catalyst has a surface area of between approximately 70 square meters/gram (m 2 /g) and approximately 150 m 2 /g.

16. The method of claim 1 , wherein the pore volume is present in pores having a diameter of between approximately 1 nm and approximately 104 nm.

17. A method for reducing a concentration of NO x in a dust containing gas stream comprising:
a. passing a first gas stream containing NO x into a contacting zone;
b. contacting the first gas stream with a catalyst bed having one or more flow paths through the catalyst bed, wherein the catalyst bed comprises a ceramic or metal foam catalyst having a NO x reduction catalyst configured to produce a second gas stream with a reduced NO x concentration, and wherein a pore volume of the NO x reduction catalyst is present in pores having a diameter of between approximately 1 nm and approximately 104 nm; and
c. passing the second gas stream out of the contacting zone, wherein the first gas stream has a dust concentration of at least 5 mg/Nm 3 and a pressure drop of the catalyst bed increases by 300% or less relative to an initial pressure drop of the catalyst bed due to dust accumulation, measured under the same conditions.

18. The method of claim 17 , wherein the second gas stream comprises at least 50% of an amount of dust in the first gas stream.

19. The method of claim 17 , wherein the NO x reduction catalyst has a surface area of between approximately 70 square meters/gram (m 2 /g) and approximately 150 m 2 /g.

Assignees

• Shell Oil Co

Inventors

• Klink Wassim
• Seng Guido
• Zhang Wenzhong
• Klemt Andreas
• Himelfarb Paul Benjerman

Classifications

• B01D53/8631 Primary

  Processes characterised by a specific device · CPC title

• B01J35/56

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

• B01D2255/90

  Physical characteristics of catalysts · CPC title

• B01D53/9431

  Processes characterised by a specific device · CPC title

• B01D53/8625 Primary

  Nitrogen oxides · CPC title