JPH0665199B2 - High frequency induction plasma equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to an organic compound by a plasma reaction method capable of efficiently decomposing an organic halogen compound containing fluorine, chlorine and bromine in an organic compound such as CFC gas and trichlorethylene. The present invention relates to a high frequency induction plasma device suitable for use in a method for decomposing a halogen compound.

(Prior Art) Organic halogen compounds containing fluorine, chlorine, and bromine in organic compounds such as CFCs and trichlorethylene are
It is widely used in large quantities in refrigerants, fire extinguishing agents, etc., and is of high importance in industry. However, these compounds are highly volatile, and most of those used in industry are released into the environment such as air, water, and soil, resulting in the destruction of the ozone layer, the formation of carcinogens, and mutagenicity. It has been pointed out that it has a serious impact on the environment such as the generation of substances.

(Problems to be Solved by the Invention) In the present situation, when a used organic halogen compound is disposed of as a waste, its reactivity is extremely low, and thus there is no suitable decomposition treatment method.

What has been conventionally reported as a decomposition treatment method is a combustion technique at high temperature. However, in this method, since the organic halogen compound is burned with a large amount of fuel such as hydrocarbon, the energy efficiency is extremely low, and
Since the fuel tank and combustion furnace are large, it is impossible to downsize the entire device. Further, free halogen generated by combustion comes into contact with the high temperature furnace wall, and particularly when the organic fluorine compound is combusted, the corrosion of the furnace is severe.

As a result of earnest research on a method capable of easily decomposing organic halogen compounds, the present inventor has found a decomposing method using plasma generated by an induction heating method using high frequency waves or microwaves or a direct current heating method. This is based on the fact that a substance is extremely reactive in a plasma state, and a hardly decomposable chemical substance such as an organic halogen compound can be decomposed in a short time.
That is, in a high temperature plasma reaching over 10,000 ° C,
Almost all molecules are thought to dissociate and decompose into atomic states.

A point to be considered in such a decomposition method using plasma is that the liquid organic halogen compound is efficiently introduced into the plasma flame. That is, even if the liquid organic halogen compound is directly introduced into the plasma flame, the liquid organic halogen compound simply passes through the plasma flame and is not decomposed. Further, when the liquid is directly introduced into the plasma flame, the state of the plasma becomes unstable, and in an extreme case, the plasma disappears.

The present invention has been made in view of the above points, and an object thereof is to provide an organohalogen compound by a plasma reaction method capable of decomposing an organohalogen compound such as Freon and trichlene with high efficiency even at a high concentration. It is to realize a high-frequency induction plasma apparatus suitable for carrying out the decomposition method, and particularly to realize an apparatus capable of efficiently supplying and decomposing a liquid organic halogen compound in plasma.

(Means for Solving the Problems) A high-frequency induction plasma device based on the present invention has a cylindrical tube, a gas supply nozzle, an RF coil wound around the tube, and a hole provided in the nozzle, A means for vaporizing a liquid substance to be jetted into the plasma formed in the tube and containing it in the carrier gas, a means for guiding the carrier gas to the holes, a cooling liquid passage provided in the nozzle, and a cooling liquid. And a means for heating the cooling liquid supplied to the cooling liquid passage.

(Operation) In the present invention, the carrier gas containing the vaporized liquid substance is supplied to the hole of the nozzle provided in the upper part of the plasma torch. In addition, a cooling liquid is supplied to the nozzle to cool the nozzle heated by the plasma flame, but the nozzle is overcooled by the cooling liquid, the carrier gas is also cooled, and the vaporized liquid contained in the carrier gas is supplied. The coolant is heated and fed to the nozzle to prevent the substance from returning to the water droplets.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings. The accompanying drawings show a system for decomposing organic halogen compounds such as CFCs using a high frequency induction plasma device according to the present invention. The induction plasma torch 1 includes a cylindrical tube 2 made of an insulating material such as quartz, a gas supply nozzle 3, an RF coil 4 wound around the tube 2, and the like. A ring-shaped groove 5 is bored in the gas supply nozzle 3, and a ring-shaped plate 6 is welded to the outer image of the groove 5. On the ring-shaped plate 6,
A large number of minute holes 7 are bored, and the groove 5 is formed in the nozzle 3
One end of the hole 8 formed inside is connected. The other end of the hole 8 is connected to the pipe 9 at the upper part of the nozzle 3.

The pipe 9 is branched in the middle, one of which is introduced into the first container 10 and the other of which is introduced into the second container 11. First
A liquid organohalogen compound 12 such as Freon 113 to be decomposed is placed in the container 10. First container
One end of a carrier gas supply pipe 13 is inserted in the organic halogen compound in 10. The other end of the carrier gas supply pipe 13 is connected to an argon gas source 15 via a flow controller 14. Water 16 is contained in the second container 11, and a carrier gas supply pipe is contained in the water 16.
One end of 17 is inserted. The other end of the carrier gas supply pipe 17 is connected to the argon gas source 15 via the flow controller 18.
It is connected to the.

A switching valve 19 is provided in the middle of the pipe 9. The switching valve 19 switches the gas from the first container 10 and the second container 11 and the gas from the argon gas source 20 to switch the nozzle 3
It is guided to the hole 8 formed in Argon gas source
The gas flow rate from 20 is controlled by the flow controller 21.

An opening 22 is provided in the lower portion of the cylindrical tube 2 that constitutes the plasma torch 1, and an exhaust tube 23 is connected to this opening 22. The exhaust pipe 23 is connected to a cyclone 24 that traps the powder substance contained in the exhaust gas. The exhaust gas that has passed through the cyclone 24 is guided to a pipe 25, which has an alkaline aqueous solution inside, for example,
It is introduced into a container 27 containing potassium hydroxide (KOH) 26. A discharge pipe 28 for the internal gas is provided at the upper part of the container 27, and the discharge pipe 28 is a container 3 in which an alkaline solid, for example, calcium oxide (CaO) 29 is contained.
It is connected to the bottom of 0. At the upper part of the container 30, a gas discharge pipe 31 for passing between the calcium oxide 29 inside is provided.

The nozzle 3 of the plasma torch 1 is provided with a ring-shaped groove 5 covered by a plate 6,
The nozzle 3 is further provided with a ring-shaped passage 32. The ring-shaped passage 32 is connected to the first hole 33 and the second hole 34 which are open to the outside at the upper part of the nozzle 3. A pipe 35 is connected to the first hole 33, and the other end of the pipe 35 reaches the cooling liquid tank 36. A pipe 37 is connected to the second hole 34, and the other end of the pipe 37 is connected to the cooling liquid in the cooling tank 36.
Inserted in 38. A pump 39 is installed in the middle of the pipe 37, and the pump 39 is a cooling liquid 38 in the cooling tank 36.
Is sucked, and the cooling liquid is guided to the ring-shaped passage 32 provided in the nozzle 3 through the pipe 37. A heater 40 and a temperature detector 41 are placed in the cooling liquid 38 in the cooling tank 36. The heater 40 is supplied with an appropriate current from the controller 42, and the temperature signal from the temperature detector 41 is controlled by the controller.
Is being supplied to 42.

The operation of the apparatus thus configured will be described below. In the initial state of the apparatus, the switching valve 19 provided in the middle of the pipe 9 is operated so that the argon gas from the argon gas source 20 is supplied into the groove 5 through the hole 8 of the nozzle 3. By supplying the argon gas to the groove 5, the argon gas is jetted into the inside of the cylindrical tube 2 from the numerous minute holes 7 provided in the plate 6. In this state, a high frequency is supplied to the RF coil 4 to ignite the plasma P by an ignition mechanism (not shown).

After that, the switching valve 19 is switched so that the argon gas from the argon gas source 20 is replaced and the gas from the first container 10 and the second container 11 is supplied into the groove 5 through the hole 8 of the nozzle 3. To In the first container 10, a carrier gas supply pipe 13 connected to an argon gas source 15 is inserted into an organic halogen compound solution 12 inside, and the carrier gas supply pipe 13 is opened inside the organic halogen compound 12. Argon gas having a proper flow rate is ejected from the end portion by the flow controller 14. As a result, the organic halogen compound becomes vapor by the bubbling of the argon gas and is contained in the gas, and is discharged from the inside of the first container 10 into the pipe 9.
Further, in the second container 11, the carrier gas supply pipe 17 connected to the argon gas source 15 is inserted into the water 16 inside, and the end portion of the pipe 17 opened into the water 16 From, the argon gas having a proper flow rate by the flow controller 18 is ejected. As a result, the water becomes vapor by the bubbling of the argon gas, is contained in the gas, and is discharged from the inside of the first container 11 into the pipe 9.

The argon gas containing the vapor of the organic halogen compound and the argon gas containing the water vapor are mixed at the branch portion J in the middle of the pipe 9, and the mixed gas is introduced into the groove 5 through the hole 8 of the nozzle 3. . The mixed gas is ejected from the groove 5 into the tube 2 through a large number of minute holes 7 provided in the plate 6, and is introduced into the plasma flame F. At this time, the temperature of plasma is 10,000 to 15,000 degrees, and the organic halogen compound and water introduced into the plasma flame F are
It decomposes at high temperature with high efficiency and undergoes the following chemical reactions.

When trichlorofluoromethane (CFC-11 ... CCl ₃ F) is decomposed in plasma as an organic halogen compound, the following reaction occurs with water.

CCl ₃ F + 2H ₂ O = CO ₂ + 3HCl + HF The exhaust gas containing the decomposed molecules is the opening 22 at the bottom of tube 2.
Through the discharge pipe 23 into the cyclone 24. At this time, when the amount of water is less than that of CFC-11, excess carbon is generated, but in this cyclone 24, fine powder such as carbon contained in the exhaust gas is trapped. Cyclone 24
The gas that has passed therethrough is introduced from the pipe 25 into the potassium hydroxide aqueous solution 26 inside the container 27. By passing the exhaust gas through the solution 26, the exhaust gas containing an acid such as HCl or HF is neutralized. The neutralized gas flows from the bottom of the container 27 to the exhaust pipe 28.
It is introduced into the inside of the container 30 through and is dehydrated by the calcium oxide 29 inside the container 30. The dehydrated gas is a stable compound that hardly affects the environment and is appropriately released into the atmosphere.

Here, since the plasma flame F is formed close to the nozzle 3, the nozzle 3 may be heated to a high temperature by the plasma flame and melted. Therefore, in this embodiment, a ring-shaped cooling water passage 32 is provided inside the nozzle 3 and a cooling liquid 38 such as water or oil is supplied from the cooling tank 36 to the cooling water passage 32. The cooling liquid 38 in the cooling tank 36 is sucked up by the pump 39, and the pipe 37,
It is guided to the cooling liquid passage 32 through the second hole 34. The cooling liquid that has passed through the cooling liquid passage 32 is returned to the cooling tank 36 through the first hole 33 and the pipe 35.

In this way, the nozzle 3 is cooled and prevented from being melted by the plasma flame F. However, when the nozzle 3 is cooled too much by the cooling liquid as compared with the temperature of the organic halogen or water, the vaporized organic halogen compound or water supplied to the groove 5 through the hole 8 is returned to the state of water droplets. Will end up. Even if the organic halogen compound or water in the form of water droplets is introduced into the plasma flame F, it is not diffused in the flame but simply passes through it, and the organic halogen compound cannot be decomposed efficiently. Therefore, in this example, the pump
The cooling liquid sucked up by 39 is heated by the heater 40. When the substance ejected into the plasma flame F is CFC, the boiling point of CFC is not so high, so the temperature of this cooling liquid is set to about 40 ° C to 50 ° C. The temperature of the cooling liquid is measured by the temperature detector 41, the temperature signal is supplied to the controller 42, and the controller 42 controls the current supplied to the heater 40 so that the temperature of the cooling liquid 38 is constantly changed to the carrier gas. The temperature of the contained organic halogen compound vapor is maintained so as not to be returned to water droplets.

Although the embodiment of the present invention has been described in detail above, the present invention is not limited to this embodiment. For example, one groove is provided in the torch nozzle, and the argon gas and the carrier gas containing the vapor of the organic halogen compound are switched and supplied by bubbling into this groove, but two grooves are provided in the nozzle. It may be configured such that the argon gas and the carrier gas containing the vapor of the organic halogen compound are switched and supplied by bubbling, and the argon gas is continuously supplied to the other. In order to decompose the organic halogen compound, vaporize the liquid organic halogen compound,
Although the present invention has been described by taking the case of introduction into plasma as an example,
In addition to the purpose of decomposing the organic halogen compound, the present invention can be applied to the case of vaporizing another liquid substance and introducing it into plasma.

Furthermore, if a heater and a thermometer are provided inside the container containing the organic halogen compound and water, and the organic halogen compound and water are constantly maintained at a temperature of about 30 ° C to 40 ° C,
Evaporation can be promoted more.

(Effects of the Invention) As described above, according to the present invention, the carrier gas containing the vaporized liquid substance is supplied to the hole of the nozzle provided in the upper portion of the plasma torch, and the cooling liquid for cooling the nozzle is provided. Since it is configured to be heated and supplied to the nozzle part, the liquid substance can be efficiently diffused in the plasma flame, and the nozzle is overcooled by the cooling liquid, and the carrier gas is also cooled to be the carrier gas. It is also prevented that the vaporized liquid substance contained therein returns to water droplets.

[Brief description of drawings]

The accompanying drawings are diagrams showing an embodiment of a decomposition system of an organic halogen compound using a high frequency induction plasma device according to the present invention. 1 ... Torch, 2 ... Tube 3 ... Gas supply nozzle, 4 ... RF coil 5 ... Groove, 6 ... Plate 7 ... Micro hole, 8 ... Hole 9,13,17,25,28 ... … Tube 10 …… First container, 11 …… Second container 12 …… Organohalogen compound 14,18,21 …… Flow controller 15 …… Argon gas source, 16 …… Water 19 …… Switching valve, 20 …… Argon gas source 22 …… Opening, 23 …… Exhaust pipe 24 …… Cyclone 26 …… Potassium hydroxide aqueous solution 27, 30 …… Container, 29 …… Calcium oxide 31 …… Discharge pipe 32 …… Passage, 33, 34 …… 35,37 …… Pipe, 36 …… Cooling tank 38 …… Coolant, 39 …… Pump 40 …… Heater, 41 …… Temperature detector 42 …… Controller

Front page continued (72) Inventor Yutaka Konuma 16-3 Onogawa, Tsukuba-shi, Ibaraki Institute of Industrial Science, Institute of Pollution Resources (72) Inventor Reiji Aizawa 16-3 Onogawa, Tsukuba-shi, Ibaraki Institute of Pollution Resources (72) ) Inventor Akira Kushiyama 16-3 Onogawa, Tsukuba-shi, Ibaraki Institute of Industrial Science and Technology (72) Inventor Satoru Kobayashi 16-3 Onogawa, Tsukuba-shi, Ibaraki Institute of Pollution Resources (72) Inventor Hideo Ouchi 16-3 Onogawa, Tsukuba-shi, Ibaraki Institute of Pollution Resources, Institute of Industrial Technology (72) Inventor Takanobu Amano 3-1, 2 Musashino, Akishima-shi, Tokyo Nihon Electronics Co., Ltd. (72) Hisashi Komaki Akishima-shi, Tokyo 3-1-2 Musashino Japan Electronics Co., Ltd. (72) Inventor Shoji Hirakawa 3-1-2 Musashino, Akishima City, Tokyo Kiyosumi Yazawa Examiner, Nihon Electronics Co., Ltd.

Claims (1)

[Claims] 1. A cylindrical tube, a gas supply nozzle, an RF coil wound around the tube, and a hole provided in the nozzle,
A means for vaporizing a liquid substance to be jetted into the plasma formed in the tube and containing it in the carrier gas, a means for guiding the carrier gas to the holes, a cooling liquid passage provided in the nozzle, and a cooling liquid. High-frequency induction plasma device comprising means for supplying a cooling liquid to the passage of the cooling liquid and means for heating the cooling liquid supplied to the passage of the cooling liquid.