Materials, methods, and devices for siloxane contaminant removal

Patent metadata

Field	Value
Publication number	US-9789435-B2
Application number	US-201314399480-A
Country	US
Kind code	B2
Filing date	Mar 15, 2013
Priority date	May 7, 2012
Publication date	Oct 17, 2017
Grant date	Oct 17, 2017

Abstract

Adsorbent materials are disclosed, along with filter elements containing the adsorbent materials methods of using adsorbents to remove siloxane contaminants from a gas stream. The method includes providing an adsorbent material that has been washed with an acid and passing a gas through the adsorbent material so as to reduce siloxane levels in the gas. A filter element for reducing siloxane levels in a gas includes a first adsorbent material, the first adsorbent material comprising an acid-washed adsorbent; and a second adsorbent material, the second adsorbent material comprising an acid-impregnated adsorbent.

First claim

We claim:

1. A method of reducing siloxane levels in a gas, the method comprising:
providing a first adsorbent material comprising activated carbon that has been washed with an acid;
passing a gas through the first adsorbent material so as to reduce siloxane levels in the gas;
providing a second adsorbent material comprising activated carbon impregnated with phosphoric acid; and
passing the gas through the second adsorbent material.

2. The method of claim 1 , wherein the gas is passed through the first adsorbent material and subsequently passed through the second adsorbent material.

3. The method of claim 1 , wherein the gas is passed through the second adsorbent material and subsequently passed through the first adsorbent material.

4. The method of claim 1 , further comprising providing an acid gas remover, wherein the ratio of first adsorbent to acid gas remover is from 3:1 to 1:3.

5. A filter element for reducing siloxane levels in a gas, the filter element comprising:
a first adsorbent material, the first adsorbent material comprising an activated carbon that has been acid-washed; and
a second adsorbent material, the second adsorbent material comprising an activated carbon impregnated with phosphoric acid.

6. The filter element of claim 5 , wherein the first adsorbent material comprises silica gel.

7. The filter element of claim 5 , wherein the acid of the acid-wash comprises a strong acid.

8. The filter element of claim 5 , wherein the acid of the acid-wash comprises nitric acid.

9. The filter element of claim 5 , wherein the acid-wash comprises an aqueous solution of at least 5 percent nitric acid.

10. The filter element of claim 5 , wherein the filter element is configured for a gas to first pass through the first adsorbent material and subsequently pass through the second adsorbent material.

11. The filter element of claim 5 , wherein the filter element is configured for a gas to first pass through the second adsorbent material and subsequently pass through the first adsorbent material.

12. The filter element of claim 5 , further comprising an acid gas remover.

13. The filter element of claim 12 , wherein the acid gas remover comprises an adsorbent impregnated with an impregnate selected from the group consisting of: potassium iodide, potassium carbonate, and combinations thereof.

14. The filter element of claim 12 , wherein the ratio of first adsorbent to acid gas remover is from 3:1 to 1:3.

15. A filtration system for reducing siloxane levels in a gas, the filtration system comprising:
a first filter element comprising a first adsorbent material, the first adsorbent material comprising an activated carbon that has been acid-washed;
a second filter element comprising a second adsorbent material, the second adsorbent material comprising an activated carbon impregnated with phosphoric acid; and
wherein the filter system is configured in a series for a majority of the gas to pass through the first filter element and the second filter element.

16. The system of claim 15 , wherein the first adsorbent material is selected from the group silica gel, activated alumina, zeolites, nanoporous supports, and combinations thereof.

17. The system of claim 15 , wherein the acid of the acid-washed adsorbent comprises nitric acid.

Assignees

• Donaldson Co Inc
• Donaldson Comapany Inc

Inventors

• Hoang Brian N
• Weineck Gerald
• Viswanathan Karthik
• Dallas Andrew J

Classifications

• B01D2253/106

  Silica or silicates · CPC title

• B01J20/28052

  Several layers of identical or different sorbents stacked in a housing, e.g. in a column · CPC title

• B01J20/186

  Chemical treatments in view of modifying the properties of the sieve, e.g. increasing the stability or the activity, also decreasing the activity · CPC title

• B01J20/08

  comprising aluminium oxide or hydroxide; comprising bauxite · CPC title

• B01D2257/55

  Compounds of silicon, phosphorus, germanium or arsenic · CPC title