Ozone purification process

• US 6,190,436 B1
• Filed: 03/05/1999
• Issued: 02/20/2001
• Est. Priority Date: 03/05/1999
• Status: Expired due to Fees

• Current Assignee: BOC Group Pty Limited (Linde Plc)
• Original Assignee: BOC Group Pty Limited (Linde Plc)
• Inventors: Ji, Wenchang, Ferrell, Robert James, Shirley, Arthur I.
• Primary Examiner(s): Spitzer, Robert H.
• Application Number:
  US09/263,615
• Time in Patent Office: 718 Days
• Field of Search: 95/45, 95/47--55, 96/4, 96/7--14, 204/176, 422/186.07, 422/186.08, 422/186.11, 422/186.12
• US Class Current: 95/45
• CPC Class Codes: B01D 2313/18 Specific valves
• CPC Class Codes: B01D 2313/221 Heat exchangers
• CPC Class Codes: B01D 53/22 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 Class Codes: B01D 53/228 characterised by specific membranes
• CPC Class Codes: B01D 63/02 Hollow fibre modules
• CPC Class Codes: B01D 63/06 Tubular membrane modules
• CPC Class Codes: B01D 63/069 comprising a bundle of tubular membranes
• CPC Class Codes: B01D 63/087 Single membrane modules
• CPC Class Codes: C01B 13/10 Preparation of ozone
• CPC Class Codes: C02F 1/78 with ozone C02F1/4672 takes precedence

Abstract

An ozone-oxygen gas stream is introduced into feed side of a membrane separation unit containing an elastomeric polymer membrane. Ozone-enriched gas passes through the membrane to a permeate zone and is contacted with an ozone-reactive substance-containing gas stream in the permeate zone, thereby oxidizing the substances or is removed from the permeate zone. Removal of the ozone-enriched gas from the permeate zone may be effected by purging the permeate zone with an inert gas and/or evacuating the permeate zone. Ozone-enriched gas removed from the permeate zone may be mixed with a liquid or gas stream which contains ozone-reactive substances in, for example, a venturi device, thereby oxidizing the substances.

Claims

1. A process comprising the steps:

(a) introducing a gas mixture comprising ozone and oxygen into the feed zone of gas separation means comprising a feed zone and a permeate zone separated by an ozone-permeable membrane comprising an elastomeric polymer, silica or combinations thereof, thereby permeating an ozone-enriched gas into said permeate zone and producing an oxygen-enriched gas in said feed zone;

(b) removing said oxygen-enriched gas from said feed zone; and

(c) removing ozone from said permeate zone.

2. The process of claim 1, wherein step (a) is carried out at a temperature in the range of about −

120 to about 100°

C. and at a pressure in the range of about 0.8 to about 20 bara.

3. The process of claim 1, wherein step (c) is carried out by:

(1) purging said permeate zone with inert gas;

(2) evacuating said permeate zone;

or (3) purging said permeate zone with inert gas and evacuating said permeate zone.

4. The process of claim 3, further comprising contacting the ozone removed from said permeate zone with a fluid stream containing at least one ozone-reactive substance.

5. The process of claim 4, wherein said at least one ozone-reactive substance comprises hydrogen, carbon monoxide, nitrogen compounds, sulfur compounds, organic compounds, microbiological agents or mixtures thereof.

6. The process of claim 5, wherein said fluid stream is an aqueous stream.

7. The process of claim 6, wherein said aqueous stream is drinking water, wastewater or semiconductor cleaning liquid.

8. The process of claim 5, wherein said fluid stream is a gas stream.

9. The process of claim 8, wherein said gas stream is air, a breathable gas or an exhaust gas from a combustion process.

10. The process of claim 5, wherein said one or more ozone-reactive substances are organic compounds selected from the group consisting of C₁-C₃ hydrocarbons;

nitrogen compounds selected from the group consisting of nitrogen oxides;

sulfur compounds selected from the group consisting of sulfur dioxide and hydrogen sulfide;

microbiological agents selected from the group consisting of viruses and living organisms;

or mixtures thereof.

11. The process of claim 3, wherein step (c) is carried out by (2) or (3), and said removal is effected by means of a venturi device.

12. The process of claim 3, wherein step (c) is carried out by (1) or (3) and said inert gas is comprised predominantly of nitrogen, carbon dioxide, argon or mixtures thereof.

13. The process of claim 1, wherein step (c) is carried out by passing a gas stream containing at least one ozone-reactive substance through said permeate zone.

14. The process of claim 3 or claim 13, wherein step (a) is carried out at a temperature in the range of about −

100 to about 0°

C.

15. The process of claim 1, wherein said elastomeric polymer comprises silicone-based polymers, ethylene-propylene terpolymer, fluorocarbon elastomer, polyurethane or combinations thereof.

16. The process of claim 15, wherein step (a) is carried out at a pressure in the range of about 0 to about 10 bara.

17. The process of claim 15, wherein step (a) is carried out at a temperature in the range of about −

80 to about −

30°

C.

18. The process of claim 15, wherein said silicone-based polymers comprises silicone rubber.

19. The process of claim 18, wherein step (a) is carried out at a pressure in the range of about 1.5 to about 5 bara.

20. The process of claim 1, further comprising cooling at least one of said gas mixture and said gas separation means by vaporizing liquid oxygen.

21. The process of claim 20, further comprising introducing said vaporizing oxygen to an ozone generator which produces said gas mixture.

22. The process of claim 21, further comprising recycling said oxygen-enriched gas to said ozone generator.

23. The process of claim 22, further comprising removing gaseous impurities from said oxygen-enriched gas prior to recycling it to said ozone generator.

24. Apparatus for mixing a fluid with a gas comprising:

(a) gas separation means having a gas mixture inlet, a first separated gas outlet and a second separated gas outlet, said gas separation means being adapted to separate a gas mixture introduced thereinto through said gas mixture inlet into a first separated gas and a second separated gas and to discharge said first separated gas through said first separated gas outlet and said second separated gas through said second separated gas outlet;

(b) a carrier fluid-first separated gas mixing device having a carrier fluid inlet, a first separated gas inlet, a mixture outlet and a venturi connected to said carrier fluid inlet, said first separated gas inlet and said mixture outlet, said mixing device being adapted to cause a stream of carrier fluid passing through said venturi at superatmospheric pressure to draw first separated gas into said carrier fluid and discharge carrier fluid-first separated gas mixture from said mixing device through said mixture outlet;

(c) first fluid flow means connecting said first separated gas outlet of said gas separation means to said first separated gas inlet of said mixing device; and

(d) second fluid flow means adapted to provide a carrier fluid to said carrier fluid inlet of said gas mixing device at superatmospheric pressure.

25. The apparatus of claim 24, wherein said gas mixture comprises ozone and oxygen, said first separated gas is ozone-enriched gas, said second separated gas is oxygen-enriched gas and said carrier fluid is a liquid or gas containing ozone-reactable substances.

26. The apparatus of claim 25, wherein said gas separation means comprises an ozone-permeable membrane.

27. The apparatus of claim 26, wherein said ozone-permeable membrane is comprised of an elastomeric polymer, silica or combinations thereof.

28. The apparatus of claim 27, further comprising third fluid flow means connecting a source of ozone-oxygen gas mixture to said gas mixture inlet of said gas separation means, said third fluid flow means including heat exchange means adapted to cool said gas mixture.

29. The apparatus of claim 28, wherein said heat exchange means comprises a liquid oxygen evaporator having a liquid oxygen inlet, a gaseous oxygen outlet, an ozone-oxygen gas mixture inlet connected to a source of ozone-oxygen gas mixture and a cooled ozone-oxygen gas mixture outlet connected to said first conduit means gas mixture inlet of said gas separation means.

30. The apparatus of claim 29, wherein said source of ozone-oxygen gas mixture comprises an ozone generator having an oxygen feed gas inlet and an ozone-oxygen gas mixture outlet;

and further comprising fourth fluid flow means connecting a source of liquid oxygen to said liquid oxygen inlet of said evaporator;

fifth fluid flow means connecting said gaseous oxygen outlet of said evaporator to said oxygen feed gas inlet of said ozone generator; and

wherein said ozone-oxygen gas mixture outlet of said evaporator is connected to said gas mixture inlet of said gas separation means.

31. The apparatus of claim 30, further comprising sixth fluid flow means connecting said second separated gas outlet of said gas separation means to said ozone generator.

32. The apparatus of claim 27, wherein said elastomeric polymer comprises silicone-based polymers, ethylene-propylene terpolymer, fluorocarbon elastomer, polyurethane or combinations thereof.

33. The apparatus of claim 32, wherein said silicone-based polymers comprises silicone rubber.