Claims
- 1. A microwave plasma generator comprising:
a rectangular waveguide having a hole to transmit a microwave; a coaxial microwave cavity connected to said rectangular waveguide by communicating with the hole; and a discharge tube which is made of a dielectric material, extends through the hole of said rectangular waveguide, and extends through said cavity so as to be coaxial with a central axis of said cavity, wherein said discharge tube has a double-tube structure including outer and inner tubes, a sectional area of an annular gap formed between said outer and inner tubes is constant over an entire length of said inner tube, and an end portion of said inner tube has a gas injection opening having the same diameter as an internal cavity of said inner tube.
- 2. A generator according to claim 1, further comprising an ignition electrode installed in said inner tube to generate microwave discharge.
- 3. A generator according to claim 1, further comprising an ignition coil installed in said inner tube to generate microwave discharge.
- 4. A generator according to any one of claims 1 to 3, further comprising a gas supply pipe installed in the gap between said outer and inner tubes along the direction of tangent of said outer tube.
- 5. A microwave plasma generator comprising:
a rectangular waveguide having a hole to transmit a microwave; a cylindrical microwave resonance cavity which is connected to said rectangular waveguide by communicating with the hole and is placed such that a central axis of said resonance cavity aligns with the direction of electric field in said rectangular waveguide; and a discharge tube which is made of a dielectric material, extends through the hole of said rectangular waveguide, and extends through said resonance cavity so as to be coaxial with the central axis of said cavity, wherein said discharge tube has a double-tube structure including outer and inner tubes, a sectional area of an annular gap formed between said outer and inner tubes is constant over an entire length of said inner tube, and an end portion of said inner tube has a gas injection opening having the same diameter as an internal cavity of said inner tube.
- 6. A generator according to claim 5, further comprising an ignition electrode installed in said inner tube to generate microwave discharge.
- 7. A generator according to claim 5, further comprising an ignition coil installed in said inner tube to generate microwave discharge.
- 8. A generator according to any one of claims 5 to 7, further comprising a gas supply pipe installed in the gap between said outer and inner tubes along the direction of tangent of said outer tube.
- 9. A method of decomposing an organic halide, which decomposes an organic halide in a plasma by using a microwave plasma generator comprising a rectangular waveguide having a hole to transmit a microwave, a coaxial microwave cavity connected to said rectangular waveguide by communicating with the hole, and a discharge tube which is made of a dielectric material, extends through the hole of said rectangular waveguide, and extends through said cavity so as to be coaxial with a central axis of said cavity, wherein said discharge tube has a double-tube structure including outer and inner tubes, a sectional area of an annular gap formed between said outer and inner tubes is constant over an entire length of said inner tube, and an end portion of said inner tube has a gas injection opening having the same diameter as an internal cavity of said inner tube,
wherein a gas containing the organic halide, water vapor, and air is supplied to the annular gap formed between said outer and inner tubes to generate a plasma, in said outer tube, which extends from the vicinity of the end portion of said inner tube toward an end portion of said outer tube.
- 10. A method of decomposing an organic halide, which decomposes an organic halide in a plasma by using a microwave plasma generator comprising a rectangular waveguide having a hole to transmit a microwave, a coaxial microwave cavity connected to said rectangular waveguide by communicating with the hole, and a discharge tube which is made of a dielectric material, extends through the hole of said rectangular waveguide, and extends through said cavity so as to be coaxial with a central axis of said cavity, wherein said discharge tube has a double-tube structure including outer and inner tubes, a sectional area of an annular gap formed between said outer and inner tubes is constant over an entire length of said inner tube, and an end portion of said inner tube has a gas injection opening having the same diameter as an internal cavity of said inner tube,
wherein the organic halide is supplied into said inner tube, and a gas containing water vapor and air is supplied to the annular gap formed between said outer and inner tubes, thereby generating a plasma, in said outer tube, which extends from the vicinity of the end portion of said inner tube toward an end portion of said outer tube.
- 11. A method of decomposing an organic halide, which decomposes an organic halide in a plasma by using a microwave plasma generator comprising a rectangular waveguide having a hole to transmit a microwave, a cylindrical microwave resonance cavity connected to said rectangular waveguide by communicating with the hole and placed such that a central axis of said resonance cavity aligns with the direction of electric field in said rectangular waveguide, and a discharge tube which is made of a dielectric material, extends through the hole of said rectangular waveguide, and extends through said resonance cavity so as to be coaxial with the central axis of said cavity, wherein said discharge tube has a double-tube structure including outer and inner tubes, a sectional area of an annular gap formed between said outer and inner tubes is constant over an entire length of said inner tube, and an end portion of said inner tube has a gas injection opening having the same diameter as an internal cavity of said inner tube,
a gas containing the organic halide, water vapor, and air is supplied to the annular gap formed between said outer and inner tubes to generate a plasma, in said outer tube, which extends from the vicinity of the end portion of said inner tube toward an end portion of said outer tube.
- 12. A method of decomposing an organic halide, which decomposes an organic halide in a plasma by using a microwave plasma generator comprising a rectangular waveguide having a hole to transmit a microwave, a cylindrical microwave resonance cavity connected to said rectangular waveguide by communicating with the hole and placed such that a central axis of said resonance cavity aligns with the direction of electric field in said rectangular waveguide, and a discharge tube which is made of a dielectric material, extends through the hole of said rectangular waveguide, and extends through said resonance cavity so as to be coaxial with the central axis of said cavity, wherein said discharge tube has a double-tube structure including outer and inner tubes, a sectional area of an annular gap formed between said outer and inner tubes is constant over an entire length of said inner tube, and an end portion of said inner tube has a gas injection opening having the same diameter as an internal cavity of said inner tube,
the organic halide is supplied into said inner tube, and a gas containing water vapor and air is supplied to the annular gap formed between said outer and inner tubes, thereby generating a plasma, in said outer tube, which extends from the vicinity of the end portion of said inner tube toward an end portion of said outer tube.
- 13. A microwave plasma generator comprising:
a rectangular waveguide having a hole to transmit a microwave; a cylindrical microwave resonance cavity which is connected to said rectangular waveguide by communicating with the hole and is placed such that a central axis of said resonance cavity aligns with the direction of electric field in said rectangular waveguide; a discharge tube which is made of a dielectric material, extends through the hole of said rectangular waveguide, and extends through said resonance cavity so as to be coaxial with the central axis of said cavity; and a metal conductor which is connected, while being fitted in said discharge tube, to a portion of said discharge tube near the hole, and extends into said resonance cavity through the hole.
- 14. A generator according to claim 13, wherein said cylindrical microwave resonance cavity internally forms an electric field of TM010 mode.
- 15. A microwave plasma generator comprising:
a rectangular waveguide having a hole to transmit a microwave; a cylindrical microwave resonance cavity which is connected to said rectangular waveguide by communicating with the hole and is placed such that a central axis of said resonance cavity aligns with the direction of electric field in said rectangular waveguide; a discharge tube which is made of a dielectric material, extends through the hole of said rectangular waveguide, and extends through said resonance cavity so as to be coaxial with the central axis of said cavity; a metal conductor which is connected, while being fitted in said discharge tube, to a portion of said discharge tube near the hole, and extends into said resonance cavity through the hole; and a slidable probe antenna which is interposed between said metal conductor and said discharge tube so as to be slidable in an axial direction of said discharge tube, and extends into said resonance cavity through the hole in said rectangular waveguide.
- 16. A generator according to claim 15, wherein said cylindrical microwave resonance cavity internally forms an electric field of TM010 mode.
- 17. A microwave plasma generator comprising:
a rectangular waveguide having a hole to transmit a microwave; a cylindrical microwave resonance cavity which is connected to said rectangular waveguide by communicating with the hole, is placed such that a central axis of said resonance cavity aligns with the direction of electric field in said rectangular waveguide, and has an end plate on a bottom portion; a discharge tube which is made of a dielectric material, extends through the hole of said rectangular waveguide, and extends through said resonance cavity so as to be coaxial with the central axis of said cavity; a metal conductor which is connected, while being fitted in said discharge tube, to a portion of said discharge tube near the hole, and extends into said resonance cavity through the hole; and an annular metal conductor which is interposed between said end plate of said resonance cavity and said discharge tube extending through said end plate, and extends from the outside to the inside of said cavity.
- 18. A generator according to claim 17, wherein said cylindrical microwave resonance cavity internally forms an electric field of TM010 mode.
- 19. A microwave plasma generator comprising:
a rectangular waveguide having a hole to transmit a microwave; a cylindrical microwave resonance cavity which is connected to said rectangular waveguide by communicating with the hole, is placed such that a central axis of said resonance cavity aligns with the direction of electric field in said rectangular waveguide, and has an end plate on a bottom portion; a discharge tube made of a dielectric material, extends through the hole of said rectangular waveguide, and extends through said resonance cavity so as to be coaxial with the central axis of said cavity; and a metal conductor which is connected, while being fitted in said discharge tube, to a portion of said discharge tube near the hole, and extends into said resonance cavity through the hole, wherein said end plate of said resonance cavity has a tapered projection, which projects toward said metal conductor, in a portion through which said discharge tube extends.
- 20. A generator according to claim 19, wherein said cylindrical microwave resonance cavity internally forms an electric field of TM010 mode.
- 21. A method of decomposing an organic halide, wherein a thermal plasma is generated by irradiating a gas containing an organic halide with a microwave, thereby decomposing the organic halide.
- 22. A method according to claim 21, wherein the gas is a gas mixture of the organic halide and water vapor.
- 23. A method according to claim 21, wherein water is sprayed into the thermal plasma of the gas containing the organic halide.
- 24. A method according to claim 21, alkali water is sprayed into the thermal plasma of the gas containing the organic halide, thereby decomposing the organic halide and making a product harmless.
- 25. A system for decomposing an organic halide, comprising:
a rectangular waveguide having a hole to transmit a microwave; a coaxial microwave cavity connected to said rectangular waveguide by communicating with the hole; a reaction tube placed below said cavity; a discharge tube made of a dielectric material, extending through the hole of said rectangular waveguide and extending into said reaction tube through said cavity so as to be coaxial with the central axis of said cavity; a metal conductor which is connected, while being fitted in said discharge tube, to a portion of said discharge tube near the hole, and extends into said resonance cavity through the hole; a vessel into which a lower end of said reaction tube is inserted and which contains an aqueous alkali solution; and gas supply means for supplying a gas containing an organic halide to said discharge tube.
- 26. A system for decomposing an organic halide, comprising:
a rectangular waveguide having a hole to transmit a microwave; a coaxial microwave cavity connected to said rectangular waveguide by communicating with the hole; a reaction tube placed below said cavity; a discharge tube which is made of a dielectric material, extends through the hole of said rectangular waveguide, and extends into said reaction tube through said cavity so as to be coaxial with the central axis of said cavity; a metal conductor which is connected, while being fitted in said discharge tube, to a portion of said discharge tube near the hole, and extends into said resonance cavity through the hole; a vessel into which a lower end of said reaction tube is inserted and which contains an aqueous alkali solution; gas supply means for supplying a gas containing an organic halide to said discharge tube through first piping; water supply means connected to said first piping through second piping; and heating means, provided for said second piping, for converting water flowing in said second piping into water vapor.
- 27. A system for decomposing an organic halide, comprising:
a rectangular waveguide having a hole to transmit a microwave; a coaxial microwave cavity connected to said rectangular waveguide by communicating with the hole; a reaction tube placed below said cavity; a discharge tube which is made of a dielectric material, extends through the hole of said rectangular waveguide, and extends into said reaction tube through said cavity so as to be coaxial with the central axis of said cavity; a metal conductor which is connected, while being fitted in said discharge tube, to a portion of said discharge tube near the hole, and extends into said resonance cavity through the hole; a vessel into which a lower end of said reaction tube is inserted and which contains an aqueous alkali solution; gas supply means for supplying a gas containing an organic halide to said discharge tube; and water vapor spraying means, formed in a circumferential wall of said reaction tube, for spraying water vapor into a thermal plasma generation region near a lower end portion of said discharge tube.
- 28. A system for decomposing an organic halide, comprising:
a rectangular waveguide having a hole to transmit a microwave; a coaxial microwave cavity connected to said rectangular waveguide by communicating with the hole; a reaction tube placed below said cavity; a discharge tube which is made of a dielectric material, extends through the hole of said rectangular waveguide, and extends into said reaction tube through said cavity so as to be coaxial with the central axis of said cavity; a metal conductor which is connected, while being fitted in said discharge tube, to a portion of said discharge tube near the hole, and extends into said resonance cavity through the hole; a vessel into which a lower end of said reaction tube is inserted and which contains an aqueous alkali solution; gas supply means for supplying a gas containing an organic halide to said discharge tube; and alkali water spraying means, formed in a side wall of said reaction tube, for spraying alkali water into a thermal plasma generation region near a lower end portion of said discharge tube.
- 29. A system for decomposing an organic halide, comprising:
a rectangular waveguide having a hole to transmit a microwave; a coaxial microwave cavity connected to said rectangular waveguide by communicating with the hole; a reaction tube placed below said cavity; a discharge tube which is made of a dielectric material, extends through the hole of said rectangular waveguide, and extends into said reaction tube through said cavity so as to be coaxial with the central axis of said cavity; a metal conductor which is connected, while being fitted in said discharge tube, to a portion of said discharge tube near the hole, and extends into said resonance cavity through the hole; a vessel into which a lower end of said reaction tube is inserted and which contains an aqueous alkali solution; gas supply means for supplying a gas containing an organic halide to said discharge tube; and heating means, installed in at least one of a position around said reaction tube and a position below said vessel, for vaporizing the aqueous alkali solution in said vessel and introducing water vapor into a thermal plasma generation region near a lower end portion of said discharge tube.
Priority Claims (1)
Number |
Date |
Country |
Kind |
10-302994 |
Oct 1998 |
JP |
|
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This is a continuation of Application No. PCT/JP99/05862, filed Oct. 22, 1999.
Divisions (1)
|
Number |
Date |
Country |
Parent |
09602297 |
Jun 2000 |
US |
Child |
10015366 |
Dec 2001 |
US |
Continuations (1)
|
Number |
Date |
Country |
Parent |
PCT/JP99/05862 |
Oct 1999 |
US |
Child |
09602297 |
Jun 2000 |
US |