Method of pumping gas

Patent metadata

Field	Value
Publication number	US-9023133-B2
Application number	US-31074207-A
Country	US
Kind code	B2
Filing date	Aug 2, 2007
Priority date	Sep 6, 2006
Publication date	May 5, 2015
Grant date	May 5, 2015

Abstract

A vacuum pumping arrangement is described for pumping a gas stream containing hydrogen or other hydrogen-containing gas. The arrangement comprises a pumping mechanism for receiving the gas stream and exhausting a pumped gas stream at a sub-atmospheric pressure, and, downstream from the pumping mechanism, an ionic conducting membrane having one side exposed to the pumped gas stream and another side exposed to oxygen or other source of oxygen. In one example, the membrane is permeable to hydrogen, which permeates across the membrane to react with oxygen adsorbed on the other surface of the membrane. In another example, the membrane is permeable to oxygen anions, which permeate across the membrane to react with hydrogen within the gas stream.

First claim

I claim:

1. A method of pumping a gas stream containing hydrogen comprising the steps of:
conveying the gas stream through a vacuum pumping mechanism;
subsequently conveying the gas stream at a sub-atmospheric pressure through a membrane reactor attached to an exhaust flange of the vacuum pump mechanism such that the gas stream is conveyed to a first side of a membrane permeable to oxygen ions within the membrane reactor wherein the first side of the membrane comprises a catalyst to catalyze the oxidation of a hydrocarbon or hydrogen in the gas stream; and
exposing a second side of the membrane to a gaseous source of oxygen, wherein the second side of the membrane comprises a material to disassociate oxygen into oxygen ions so that the oxygen ions permeate across the membrane to react with the hydrocarbon or hydrogen in the gas stream thereby inhibiting hydrogen from back streaming through the pumping mechanism.

2. The method according to claim 1 wherein the pumping mechanism comprises a molecular pumping mechanism.

3. The method according to claim 2 wherein the pumping mechanism comprises a turbomolecular pumping mechanism.

4. The method according to claim 1 wherein the gas stream is conveyed to the first side of the membrane at a pressure less than 50 mbar absolute.

5. The method according to claim 1 wherein the gas stream is conveyed to the first side of the membrane at a pressure less than 10 mbar absolute.

6. A method of pumping a gas stream containing hydrogen comprising the steps of:
conveying the gas stream through a vacuum pumping mechanism;
subsequently conveying the gas stream at a sub-atmospheric pressure to a membrane reactor attached to an exhaust flange of the vacuum pump mechanism such that the gas stream comes in contact with a first side of an oxygen anion conducting membrane within the membrane reactor;
exposing a second side of the membrane to a gaseous source of oxygen, so that oxygen from the oxygen source disassociates proximate the second side of the membrane to form oxygen ions that permeate across the membrane to react with hydrogen in the gas stream and thereby inhibiting hydrogen from back streaming through the pumping mechanism.

7. The method according to claim 6 wherein the membrane is heated to a temperature of at least 300° C.

8. The method according to claim 7 wherein a potential difference is applied across the membrane to promote permeation of oxygen ions across the membrane.

9. The method according to claim 8 , wherein an inner surface of the membrane is exposed to the oxygen source, and an outer surface of the membrane is exposed to the gas stream.

10. A vacuum pumping arrangement for pumping a gas stream containing hydrogen, the arrangement comprising:
a vacuum pumping mechanism receiving the gas stream and exhausting a pumped gas stream at a sub-atmospheric pressure;
a membrane reactor attached to an exhaust flange of the vacuum pumping mechanism, the reactor comprising a membrane permeable to oxygen ions, wherein the membrane has a first side for exposure to the pumped gas stream and a second side for exposure to a gaseous source of oxygen and wherein oxygen ions are formed through dissociation at the membrane and pass through the membrane and react with hydrogen in the pumped gas stream so as to remove hydrogen from the pumped gas stream.

11. The pumping arrangement according to claim 10 wherein the pumping mechanism comprises a molecular pumping mechanism.

12. The pumping arrangement according to claim 11 wherein the molecular pumping mechanism comprises a turbomolecular pumping mechanism.

13. The pumping arrangement according to claim 10 wherein the sub-atmospheric pressure is less than 50 mbar absolute.

14. The pumping arrangement according to claim 10 further comprising a second pumping mechanism located downstream from the membrane.

15. The method of claim 1 wherein the gas stream contains molecular hydrogen.

16. The method of claim 1 wherein when ions from one of the gas stream and the oxygen source permeate across the membrane to react with the other of the gas stream and the oxygen source, the reaction produces water.

17. The vacuum pumping arrangement of claim 10 wherein the gas stream contains molecular hydrogen.

18. The vacuum pumping arrangement of claim 10 wherein when BOO of hydrogen ions and oxygen ions pass through the membrane and react with the other of the hydrogen ions and the oxygen ions so as to remove hydrogen from the pumped gas stream, the reaction produces water.

Assignees

• Grant Robert Bruce
• Edwards Ltd

Inventors

• Grant Robert Bruce

Classifications

• B01D53/22

  by diffusion (manufacturing semi-permeable membranes B01D67/00; form, structure or properties of semi-permeable membranes B01D69/00; material for semi-permeable membranes B01D71/00) · CPC title

• B01D2257/70

  Organic compounds not provided for in groups B01D2257/00 - B01D2257/602 · CPC title

• C23C16/4412 Primary

  Details relating to the exhausts, e.g. pumps, filters, scrubbers, particle traps · CPC title

• B01D2257/104

  Oxygen · CPC title