Treatment of liquids

• US 20020014400A1
• Filed: 06/07/2001
• Published: 02/07/2002
• Est. Priority Date: 03/14/1998
• Status: Active Grant

• Current Assignee: Professional Scientific Limited
• Original Assignee: Splits Technologies Limited
• Inventors: Taktakishvili, Merab Ivanovich, Kossyi, Igor Antonovich, Barkhudarov, Eduard Mikhailovich, Zadiraka, Yuri Vladimirovich
• Granted Patent: US 6,558,638 B2
• Time in Patent Office: Days
• US Class Current: 204/158.2
• CPC Class Codes: B01D 17/0205 by gas bubbles or moving solids
• CPC Class Codes: B01D 17/06 Separation of liquids from each other by electricity
• CPC Class Codes: B01D 21/0009 Settling tanks making use of electricity or magnetism electric ultra filters B01D61/425; filters making use of electricity or magnetism B01D35/06; magnetic or electrostatic separation B03C
• CPC Class Codes: B01F 23/23123 consisting of rigid porous or perforated material
• CPC Class Codes: B01F 23/231231 the outlets being in the form of perforations
• CPC Class Codes: B01F 23/231265 being tubes, tubular elements, cylindrical elements or set of tubes
• CPC Class Codes: B01F 23/2323 by circulating the flow in guiding constructions or conduits
• CPC Class Codes: B01F 25/53 in which the mixture is discharged from and reintroduced into a receptacle through a recirculation tube, into which an additional component is introduced
• CPC Class Codes: B01F 33/05 Mixers using radiation, e.g. magnetic fields or microwaves to mix the material B01F23/2133, B01F23/238, B01F23/55, B01F33/3031, B01F33/3032 take precedence
• CPC Class Codes: B01J 19/088 giving rise to electric discharges for heating purposes H05B7/00; for the production of ozone C01B13/11, H01T19/00
• CPC Class Codes: C02F 1/32 with ultraviolet light
• CPC Class Codes: C02F 1/4608 using electrical discharges
• CPC Class Codes: C02F 1/74 with air aeration of stretches of water C02F7/00
• CPC Class Codes: C02F 2001/46157 Perforated or foraminous electrodes
• CPC Class Codes: C02F 2001/46171 Cylindrical or tubular shaped
• CPC Class Codes: C02F 2101/20 Heavy metals or heavy metal compounds
• CPC Class Codes: C02F 2101/363 PCB's; PCP's
• CPC Class Codes: C02F 2103/026 Treating water for medical or cosmetic purposes
• CPC Class Codes: C02F 2103/14 Paint wastes
• CPC Class Codes: C02F 2103/42 from bathing facilities, e.g. swimming pools
• CPC Class Codes: C02F 2201/46125 : Electrical variables
• CPC Class Codes: C02F 2201/46135 : Voltage
• CPC Class Codes: C02F 2201/46175 : Electrical pulses
• CPC Class Codes: C02F 2303/04 : Disinfection
• CPC Class Codes: F02M 27/04 : by electric means, ionisation, polarisation or magnetism

Abstract

The present invention provides an apparatus suitable for use in the treatment of liquid 31, comprising a high voltage electric discharge device 8 with spaced apart first second electrodes 24,25. The discharge device has electrical power supply control means 13 for applying a series of high voltage pulses across said first and second electrodes 24,25 so as to produce an extended area electrical discharge in an electric discharge zone 37 extending between said first and second electrodes. The apparatus also has a gas delivery means 14-18,29 for feeding a series of bubbles 36 of gas into the liquid in said electric discharge zone.

The present invention also provides methods of producing an electrical discharge in a liquid and of decontaminating water and other liquids using the apparatus of the invention.

Claims

1. An apparatus suitable for use in the treatment of a liquid, said apparatus comprising a high voltage electric discharge device with a first electrode and a second electrode spaced apart from said first electrode, and dielectric support members for said first and second electrodes, with exposed opposed portions of said first and second electrodes each having a dielectric-electrode interface between the respective electrode and said supporting dielectric member whereby, in use of the apparatus, a local increase in electric field strength is induced at said exposed opposed electrode portions adjacent said dielectric support member thereby facilitating electric discharge initiation, said discharge device including electrical power supply control means formed and arranged for applying a series of high voltage pulses across exposed opposed portions of said first and second electrodes in use of the apparatus with said device connected to an electrical power supply, so as to produce and maintain, in use of the apparatus, an extended area electrical discharge in an electric discharge plasma zone extending between said exposed opposed portions of said first and second electrodes, said apparatus including a gas delivery means formed and arranged for feeding a series of bubbles of gas into a body of liquid in said electric discharge zone in direct contact with said exposed opposed portions of said first and second electrodes in use of said apparatus.

2. An apparatus according to claim 1 wherein said first and second electrodes are substantially spaced apart and there is provided a multiplicity of spaced apart secondary electrodes distributed serially in a longitudinally extending array between said opposed portions of said first and second electrodes.

3. An apparatus according to claim 2 wherein said first and second electrodes are formed and arranged so as to provide an annular electric discharge zone in use of said apparatus.

4. An apparatus according to claim 3 wherein said electric discharge zone has a substantially rectilinear longitudinal axis.

5. An apparatus according to claim 3 wherein said electric discharge zone has a longitudinal axis which is at least partly arcuate.

6. An apparatus according to claim 4 wherein said first and second electrodes have opposed annular portions.

7. An apparatus according to claim 6 wherein the first electrode also has an elongate portion extending generally parallel to the electric discharge surface and insulated therefrom by a suitable solid insulator dielectric.

8. An apparatus according to claim 7 wherein said first electrode elongate portion is in the form of a conductor extending generally along the central longitudinal axis of the electric discharge zone.

9. An apparatus according to claim 6 wherein said electric discharge zone is provided on the outside of a solid dielectric tubular insulator with an internal passage extending therealong and providing a gas supply conduit.

10. An apparatus according to claim 9 wherein is provided a plurality of discrete spaced apart passage means extending through said tubular insulator for connecting said internal passage to the exterior of said tubular insulator for delivering gas to the electric discharge zone.

11. An apparatus according to claim 3 wherein said secondary electrodes are generally annular.

12. An apparatus according to claim 3 wherein said secondary electrodes are in the form of multiplicity of metallic or other electrically conducting particles embedded in or attached to the surface of an electrically insulating substrate.

13. An apparatus according to claim 11 wherein the electrodes are spaced apart from each other by from 3 to 8 mm.

14. An apparatus according to claim 1 wherein said first and second electrodes are substantially spaced apart with a multiplicity of spaced apart secondary electrodes distributed between opposed portions of said first and second electrodes so as to provide a slipping surface discharge across said electrodes in use of the apparatus.

15. An apparatus according to claim 1 wherein said first and said second electrodes are in the form of generally planar members in opposed relation, each having a plurality of apertures therein for the passage of said liquid through first one and then the other of said electrodes via said electric discharge zone extending therebetween in use of said apparatus.

16. An apparatus according to claim 15 wherein is provided a multiplicity of said apertures distributed substantially uniformly across said electrodes.

17. An apparatus according to claim 16 wherein said apertures have an area comprising from 30 to 98% of the total area of the electrodes.

18. An apparatus according to claim 15 wherein said apparatus comprises a plurality of first and second electrode pairs substantially spaced apart from each other.

19. An apparatus according to claim 18 wherein each electrode pair is spaced from a neighbouring electrode pair by from 2 to 10 cms.

20. An apparatus according to claim 15 wherein the or each first electrode is spaced from the opposed second electrode by from 0.2 to 2 cms.

28. An apparatus according to claim 1 wherein said electrical power supply control means is formed and arranged for applying said high voltage pulses at a voltage of from 10 kv to 50 kv.

29. An apparatus according to claim 1 wherein said electrical power supply control means is formed and arranged for applying said high voltage pulses at a frequency of from 1 to 200 Hz.

30. An apparatus according to claim 1 wherein said electrical power supply control means is formed and arranged for applying said high voltage pulses with a pulse energy of from 0.01 to 50 J per pulse.

31. An apparatus according to claim 30 wherein is used a pulse energy of from 0.1 to 25 J per pulse.

32. A method of producing and maintaining an electric discharge plasma in a liquid comprising the steps of:

providing an apparatus according to claim 1 coupled to an electrical power supply and a gas supply means;

providing a body of said liquid between said exposed opposed portions of said first and second electrodes; and

applying a series of high voltage pulses to the first and second electrodes of the electric discharge device of said apparatus while feeding gas into said body of liquid.

33. A method of producing and maintaining an electric discharge plasma in a liquid comprising the steps of:

providing an apparatus according to claim 15 coupled to an electrical power supply and a gas supply means;

substantially immersing said exposed opposed portions of said planar member form first and second electrodes in the liquid; and

applying a series of high voltage pulses to the first and second electrodes of the electric discharge device of said apparatus while feeding gas to the electric discharge zone therebetween.

34. A method of treating a liquid containing at least one undesirable form of a contaminant, so as to decontaminate effectively the liquid, said method comprising the steps of producing and maintaining an electric discharge in said liquid by means of a method according to claim 32 or claim 33, for a period of time sufficient substantially to modify at least one said contaminant into a more benign form.

35. A method according to claim 34 wherein said liquid undergoing treatment has a pH of from 7 to 11 during said treatment.

36. A method according to claim 34 wherein a gas comprising oxygen is used.

37. A method of according to claim 34 wherein said water contains a microbial or another infectious agent contaminant, wherein said water is treated by a method according to claim 34.

38. A method of decontaminating water containing a heavy metal or other chemical contaminant, wherein said water is treated by a method according to claim 34.

40. An apparatus according to claim 2 wherein said first and second electrodes have opposed annular portions.

41. An apparatus according to claim 1 wherein only opposed electrode portions are exposed, other portions of said first and second electrodes and any secondary electrodes present therebetween, being covered in solid dielectric insulator material.

42. An apparatus according to claim 2 wherein only opposed electrode portions are exposed, other portions of said first and second electrodes and any secondary electrodes present therebetween, being covered in solid dielectric insulator material.

43. An apparatus according to claim 6 wherein said first and second electrodes and any secondary electrodes present therebetween, have cylindrical outer surfaces, which cylindrical outer surfaces are covered in solid dielectric insulator material.

44. An apparatus according to claim 6 wherein said electric discharge zone is provided on the outside of a solid dielectric tubular insulator with an internal passage extending therealong and providing a gas supply.

45. An apparatus according to claim 44 wherein is provided a plurality of discrete spaced apart passages extending through said tubular insulator for connecting said internal passage to the exterior of said tubular insulator for delivering gas to the electric discharge zone.

46. An apparatus according to claim 45 wherein said secondary electrodes are generally annular.

47. An apparatus according to claim 46 wherein said tubular insulator is provided with channel form recesses underneath said opposed electrode portions of said generally annular first and second electrodes and secondary electrodes, whereby in use of said apparatus said series of bubbles of gas is mixed with said liquid before entering said electric discharge zone between said opposed electrode portions.

48. An apparatus according to claim 47 wherein said tubular insulator is formed and arranged so as to extend vertically, said channel form recesses in said tubular insulator have upper portions, and said discrete passages are formed and arranged so as to exit into said upper portions of said channel form recesses.

49. An apparatus according to claim 11 wherein said tubular insulator is provided with channel form recesses underneath said opposed electrode portions of said generally annular first and second electrodes and secondary electrodes, whereby in use of said apparatus said series of bubbles of gas is mixed with said liquid before entering said electric discharge zone between said opposed electrode portions.

50. An apparatus according to claim 49 wherein said tubular insulator is formed and arranged so as to extend vertically, said channel form recesses in said tubular insulator have upper portions, and said discrete passages are formed and arranged so as to exit into said upper portions of said channel form recesses.

21. An apparatus suitable for use in the treatment of a liquid, said apparatus comprising a high voltage electric discharge device with a first electrode and a second electrode spaced apart from said first electrode, said discharge device including electrical power supply control means formed and arranged for applying a series of high voltage pulses across exposed opposed portions of said first and second electrodes in use of the apparatus with said device connected to an electrical power supply, so as to produce and maintain, in use of the apparatus, an extended area electrical discharge in an electric discharge plasma zone extending between said exposed opposed portions of said first and second electrodes, said apparatus including a gas delivery means formed and arranged for feeding a series of bubbles of gas into a body of liquid in said electric discharge zone in direct contact with said exposed opposed portions of said first and second electrodes in use of said apparatus, wherein said first electrode is provided at a nozzle means formed and arranged for directing, in use of the apparatus, a stream or jet of liquid onto said second electrode, said gas supply means being formed and arranged for injecting, in use of the apparatus, said series of bubbles of gas into said stream, said electric discharge zone extending around said stream or jet of liquid.

22. An apparatus according to claim 21 wherein said second electrode is provided in a generally funnel-form body formed and arranged for receiving and leading away liquid from said stream of liquid impinging thereon.

23. An apparatus according to claim 22 wherein is provided conduit means extending from said second funnel-form body to said nozzle and provided with pump means for circulating said liquid.

24. An apparatus according to claim 23 wherein said nozzle means and said pump means are formed and arranged for providing a jet of liquid having a diameter of from 1 to 10 mm.

25. An apparatus according to claim 21 wherein said first and second electrodes are spaced apart by from 1 to 15 cms.

26. An apparatus according to claim 24 wherein the pressure of said gas supply means is limited so as to avoid substantially, turbulence in said jet of liquid.

27. An apparatus according to claim 24 which includes support means for supporting material to be irradiated by said electric discharge in use of the apparatus, in proximity to and spaced apart from said liquid jet.

39. An UV radiation source comprising an apparatus according to claim 21.