JPH0390172A - Method and device for decomposing organic halogen compound by plasma reaction method - Google Patents

Abstract

PURPOSE:To high efficiently decompose an organic halogen compound by mixing carrier gas, in which the organic halogen compound and water are contained, to be introduced into a plasma. CONSTITUTION:A selector valve 19 is operated, and argon gas from an argon gas source 20 is supplied into a groove 5 of a nozzle 3 and jetted into the inside of a cylindrical pipe 2 from many fine holes 7. A plasma P is ignited by supplying a high frequency to an RF coil 4. Thereafter the selector valve 19 is selected to supply gas from the first and second vessels 10 and 11. In a branch part J of a pipe 9, argon gas, contained with the above described of an organic halogen compound, and argon gas, contained with steam, are mixed, introduced into the groove 5 of the nozzle 3, blown out into the pipe 2 and introduced into a plasma flame F with the organic halogen compound and water decomposed by a high temperature. Discharged gas is introduced into a cyclone 24 with fine dust of carbon or the like trapped, and the gas is introduced into a potassium oxide water solution 26 in a vessel 27 and neutralized. The gas is dewatered by calcium oxide 29 in a vessel 30, formed into a stable compound and emitted to the atmosphere.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is an organic compound that uses a plasma reaction method that can efficiently decompose organic halogen compounds containing fluorine, chlorine, and bromine in organic compounds such as fluorocarbon gas and trichlorethylene. This invention relates to a method for decomposing halogen compounds.

(Prior art) Organic halogen compounds containing fluorine, chlorine, and bromine in organic compounds such as chlorofluorocarbon gas and trichlorethylene are
It is widely used in large quantities as a refrigerant, fire extinguisher, etc., and has great importance in industry.

However, these compounds are highly volatile, and many of those used in industry are released into the environment such as the air, water, and soil, resulting in the depletion of the ozone layer.

Carcinogenic substance f! It has been pointed out that it has serious effects on the environment, such as the production of mutagenic substances.

(Problems to be Solved by the Invention) Currently, when disposing of used organic halogen compounds, there is no suitable decomposition treatment method because their reactivity is extremely low.

The decomposition treatment methods that have been reported so far are mainly high-temperature combustion techniques. However, this method has extremely low energy efficiency as it burns organic halogen compounds together with a large amount of fuel such as hydrocarbons.
Because the fuel tank and combustion furnace are large, it is not possible to downsize the entire device. Furthermore, free halogens generated during combustion come into contact with the high-temperature furnace walls, resulting in severe corrosion of the furnace, especially when organic fluorine compounds are burned.

As a result of intensive research into a method that can easily decompose organic halogen compounds, the present inventors discovered a method that can easily decompose organic halogen compounds.

We have discovered a decomposition method using plasma generated by induction heating using microwaves or direct current heating. This method utilizes the phenomenon that substances are highly reactive under plasma conditions, and is based on the fact that difficult-to-decompose chemical substances such as organic halogen compounds can be decomposed in a short period of time. That is, in high-temperature plasma reaching 10,000''C or higher, almost all molecules are considered to be dissociated and decomposed into atomic states.

What should be considered in such a decomposition method using plasma is how to efficiently guide the liquid organic halogen compound into the plasma flame. That is, even if a 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. Furthermore, if a liquid is directly introduced into a plasma flame, the state of the plasma will become unstable, and in extreme cases, the plasma will disappear.

The present invention was made in view of these points, and its purpose is to decompose organic halogen compounds such as chlorofluorocarbons and trichlene using a plasma reaction method that can decompose organic halogen compounds with high efficiency even at high concentrations. The object of the present invention is to realize a decomposition method and apparatus, and in particular, to realize a method and apparatus that can efficiently supply a liquid organic halogen compound into plasma and decompose it.

(Means for Solving the Problem) A method for decomposing an organic halogen compound by a plasma reaction method based on the invention of claim 1 is a plasma reaction method in which an organic halogen compound is introduced into plasma and the organic halogen compound is decomposed. In a method for decomposing an organic halogen compound by the method, a carrier gas is introduced into a liquid organic halogen compound and bubbled therein, and the organic halogen compound is included in the carrier gas, and at the same time, a carrier gas is introduced into water and bubbled. The present invention is characterized in that the organic halogen compound and the carrier gas containing water are mixed, and the mixed carrier gas is introduced into the plasma.

The apparatus for decomposing organic halogen compounds using a plasma reaction method according to the invention of claim 2 includes an induction plasma torch comprising a cylindrical tube, a gas supply nozzle, an RF coil wound around the tube, and a carrier gas. a first container into which a carrier gas gas from the carrier gas source is introduced and a liquid organic halogen compound contained therein; and a first container into which a carrier gas gas from the carrier gas source is introduced and into which water is placed. a carrier gas flow path that mixes a carrier gas containing an organic halogen compound from the first container and a carrier gas containing water from the second container and guides the mixture to a gas supply nozzle. It is characterized by

(Function) The inventions of claims 1 and 2 of the present invention are based on introducing water together with an organic halogen compound into the plasma, and in order to efficiently introduce the organic halogen compound and water into the plasma, argon By introducing a carrier gas such as a gas into a liquid organic halogen compound and bubbling it, the organic halogen compound is included in the carrier gas, and at the same time, by introducing a carrier gas into water and bubbling it, the organic halogen compound is included in the carrier gas. Two types of carrier gas containing water are mixed and introduced into the plasma torch, including an organic halogen compound and water.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings. The accompanying drawings show a high-frequency induction plasma apparatus for carrying out the present invention, and an induction plasma torch 1 includes a cylindrical tube 2 made of an insulating material such as quartz. It is composed of a gas supply nozzle 3, an RF coil 4 wound around a 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 outside of the groove 5. The ring-shaped plate 6 has
A large number of microholes 7 are bored, and the groove 5 is connected to the nozzle 3.
One end of a hole 8 bored inside is connected. The other end of the hole 8 is connected to a tube 9 at the top of the nozzle 3 .

The pipe 9 is branched in the middle, and one end is introduced into the first container 10 and the other end is introduced into the second container 11.

A first container 10 contains a liquid organic/percent halogen compound 12 such as Freon 113 to be decomposed. One end of the carrier gas supply pipe 13 is inserted into the organic halogen compound in the first container 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 placed in the second container 11, and this water 16
One end of a carrier gas supply pipe 17 is inserted into it. The other end of the carrier gas supply pipe 17 is connected to the flow controller 1
- connected to an argon gas source 15 via a roller 18;

A switching valve 19 is provided in the middle of the pipe 9. One switching valve switches the gas from the first container 10 and the second container 11 and the gas from the argon gas source 20 and guides it to the hole 8 formed in the nozzle 3. The gas flow rate from the argon gas source 20 is controlled by the flow controller 2.
1.

An opening 22 is provided at the bottom of the cylindrical tube 2 constituting the plasma torch 1, and an exhaust pipe 23 is provided in this opening 22.
is connected. The exhaust pipe 23 has a cyclone 24 that traps powdery substances contained in the exhausted gas.
It is connected to the. The exhaust gas that has passed through the cyclone 24 is led to a pipe 25, which is introduced into a container 27 containing an alkaline water solution, for example, potassium hydroxide (KOH) 26. A discharge pipe 28 for internal gas is provided at the upper part of the container 27, and this discharge pipe 28 is connected to the lower part of a container 30 containing an alkaline solid such as calcium oxide (CaO) 29 inside. There is. At the top of the container 30, a discharge pipe 31 is provided for the gas that has passed between the two calcium oxides inside.

The operation of the device configured as described above will be explained as follows. In the initial state of the device, the switching valve 19 provided in the middle of the pipe 9 is operated to switch on the argon gas source 20.
argon gas is supplied into the groove 5 through the hole 8 of the nozzle 3.

By supplying argon gas to the groove 5, the argon gas becomes
It is ejected into the cylindrical tube 2 from a large number of microholes 7 provided in the plate 6. In this state, a high frequency is supplied to the RF coil 4, and the plasma P is ignited by an ignition mechanism not shown.

After that, the switching valve 19 is switched, and the argon gas source 20
Gases from the first container 10 and the second container 11 are supplied into the groove 5 through the hole 8 of the nozzle 3 instead of the argon gas from the argon gas. In the first container 10, an argon gas source 1 is added to the organic halogen compound solution 12 inside.
A carrier gas supply pipe 13 connected to 5 is inserted, and the pipe 13 is open into the organic halogen compound 12.
Argon gas is ejected from the end at an appropriate flow rate by the flow controller 14. As a result, the organic halogen compound is dissolved by bubbling argon gas.
The vapor is contained in the gas and discharged from the first container 10 into the pipe 9.

Further, in the second container 11, a carrier gas supply pipe 17 connected to the argon gas source 15 is inserted into the water 16 inside, and the pipe 1 opened into the water 16 is inserted into the second container 11.
From the end of 7, argon gas is ejected at an appropriate flow rate by a flow controller 18. As a result, water becomes steam and is contained in the gas due to the bubbling of the argon gas, and is discharged from the first container 11 into the pipe 9.

At a branch J in the middle of the pipe 9, argon gas containing organic halogen compound vapor and argon gas containing water vapor are mixed, 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 micropores 7 provided in the plate 6, and introduced into the plasma flame F. At this time, the temperature of the plasma is 10,000 to 15,000 degrees, and the organic halogen compound and water introduced into the plasma flame F are
It decomposes with high efficiency at high temperatures and undergoes the chemical reactions shown below.

Trichlorofluoromethane (
When Freon-11...CCR3F) is decomposed in plasma, the following reaction occurs with water.

CCff 3 F+2H20 -CO2+3HCρ+HF The exhaust gas containing the decomposed molecules is passed through the opening 2 at the bottom of the tube 2.
2, is led into a cyclone 24 through a discharge pipe 23. At this time, if there is less water than Freon-11, excess carbon will be produced, but fine powder such as carbon contained in the exhaust gas will be trapped within the cyclone 24. The gas that has passed through the cyclone 24 is introduced into the potassium hydroxide aqueous solution 26 inside the container 27 through the pipe 25. HCI by passing exhaust gas into this solution 26.

Exhaust gases containing acids such as HF are neutralized. The neutralized gas passes from the bottom of the container 26 through the exhaust pipe 28 to the container 3.
Calcium oxide 29 inside the container 30
dehydrated by The dehydrated gas is a stable compound with little impact on the environment and is released into the atmosphere as appropriate.

FIG. 2 shows another embodiment of the invention, in which the same parts as in the embodiment of FIG. 1 are given the same numbers.

In this embodiment, the nozzle 3 of the torch 1 has a groove 51; in addition to the continuous holes 8, a hole 50 is bored in the center. Connected to the central hole 50 is a pipe 9 that serves as a passage for carrier gas from a first container 10 for bubbling an organic halogen compound and a second container for bubbling water. Further, a pipe 52 connected to the argon gas source 20 via a flow controller 51 is connected to the hole 8 .

In this embodiment, in the initial state of the apparatus, one switching valve provided in the middle of the pipe 9 is operated so that argon gas from the argon gas source 20 is supplied to the hole 50 of the nozzle 3. Further, argon gas from an argon gas source 20 is supplied to the groove 5 through the hole 8 at an appropriate flow rate by a flow controller 51 . Therefore,
Inside the tube 2, there are holes 50 and 7 in the plate 6.
Argon gas is ejected from two locations. In this state, when high frequency waves are supplied to the RF coil 4, the plasma P is ignited.

After that, switch one switching valve and switch the argon gas source 20.
Gases from the first container 10 and the second container 11 are injected into the tube 2 through the hole 50 of the nozzle 3 instead of the argon gas from the argon gas.

As a result, as in the example shown in FIG.
The organic halogen compound introduced into the plasma flame F heated to 5,000 degrees Celsius is decomposed with high efficiency as intermolecular bonds are broken by vibrations caused by the high temperature and collisions with high-energy electrons in the plasma.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to these embodiments. For example, in the first embodiment, one nozzle of the torch was provided, and argon gas and a carrier gas containing organic halogen compound vapor by bubbling were selectively supplied to this groove. Two grooves are provided, one of which is configured to switch between supplying argon gas and a carrier gas containing organic halogen compound vapor by bubbling, and the other is configured to continuously supply argon gas. Also good.

Further, in the above-mentioned embodiments, the case where water is used as a solution to react with the organic halogen compound 12 was explained as an example, but the present invention is not limited to this, and the organic halogen compound reacts with the organic halogen compound to remove the organic halogen compound. Any material may be used as long as it can be decomposed.

Furthermore, if a heater and a thermometer are provided inside the containers 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, the temperature will be even higher. Evaporation can be promoted.

(Effects of the Invention) As explained above, according to the present invention, a carrier gas such as argon gas is introduced into a liquid organic halogen compound, and the organic halogen compound vapor is contained in the carrier gas by bubbling. At the same time, a carrier gas is introduced into water and bubbled to contain water vapor in the carrier gas, and two types of carrier gas containing an organic halogen compound and water vapor are mixed and introduced into the plasma torch. Therefore, the liquid organic halogen compound can be efficiently diffused and introduced into the plasma. Further, since the liquid organic halogen compound is introduced into the plasma in a vapor state, the plasma can be maintained in a stable state.

[Brief explanation of drawings]

FIG. 1 is a diagram showing one embodiment of an organic halogen compound decomposition apparatus based on the present invention, and FIG. 2 is a diagram showing another embodiment. 1...Torch 2...Pipe 3...Gas supply nozzle 4...RF coil 5...Groove
6... Plate 7... Microhole 8
．． 50...hole 9, 13.17.25.28.52...
- Pipe 10... First container 11... Second container 12... Organic halogen compound 14.1 g, 21.51... Flow controller 15
...Argon gas source 16...Water 19...Switching valve 204...Argon gas source 22...Opening
23... Exhaust pipe 24... Cyclone 26... Potassium hydroxide aqueous solution 27.30... Two containers... Calcium oxide 31... Discharge pipe

Claims (2)

[Claims] (1) In a method for decomposing an organic halogen compound using a plasma reaction method in which the organic halogen compound is introduced into plasma and the organic halogen compound is decomposed, a carrier gas is introduced into the liquid organic halogen compound and bubbling is performed. The organic halogen compound is contained in the carrier gas, the carrier gas is introduced into water and bubbled, the water is contained in the carrier gas, and the organic halogen compound and the carrier gas containing water are mixed. A method for decomposing organic halogen compounds using a plasma reaction method in which a mixed carrier gas is introduced into the plasma. (2) an induction plasma torch consisting of a cylindrical tube, a gas supply nozzle, and an RF coil wound around the tube;
a carrier gas source; a first container into which the carrier gas gas from the carrier gas source is introduced; a liquid organic halogen compound; a carrier gas flow path that mixes a carrier gas containing an organic halogen compound from the first container and a carrier gas containing water from the second container and guides the mixture to a gas supply nozzle; A device for decomposing organic halogen compounds using a plasma reaction method.