JP2002193842A - Equipment for decomposing organohalogen compound and method for operational control thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively prevent discharge tubes from melt breakage in feeding steam. SOLUTION: The objective method for the operational control of an equipment for decomposing a CFCs gas as an organohalogen compound comprises the following practice: after converting an argon gas fed into the equipment system to a plasmatic form but before starting feeding steam to be run prior to starting feeding the CFCs gas, a feed of air is started; meanwhile an argon gas feed which has been stopped temporarily after starting feeding the steam is started again prior to starting feeding the CFCs gas, while the feed of air is stopped simultaneously with starting feeding the CFCs gas.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic halogen compound decomposing apparatus for decomposing an organic halogen compound by using plasma generated by microwaves, and a method for controlling the operation of the apparatus.

[0002]

2. Description of the Related Art Organic halogen compounds such as fluorocarbon, trichloromethane, and halon containing fluorine, chlorine, and bromine in a molecule are widely used in a wide range of applications such as refrigerants, solvents, and fire extinguishers. Is very important.
However, these compounds have high volatility and if released untreated into the atmosphere, soil, water, etc., may cause adverse effects on the environment, such as formation of carcinogenic substances and destruction of the ozone layer. It is necessary to perform detoxification treatment from the viewpoint of environmental protection.

[0003] Conventionally, methods for treating organic halogen compounds have been reported which mainly utilize a decomposition reaction at a high temperature, and these treatment methods are further roughly classified into an incineration method and a plasma method. Further, as the latter apparatus for decomposing an organic halogen compound according to the plasma method, an apparatus which generates plasma using microwaves has been developed in recent years.

[0004] As one example, a cylindrical waveguide extending vertically above a plasma generating section (decomposing section);
A discharge tube disposed inside the cylindrical waveguide and penetrating the lower end thereof and communicating with the reaction tube, a rectangular waveguide extending in the horizontal direction and connected to the cylindrical waveguide near one end thereof, A decomposition device including a microwave oscillator and the like mounted on the other end of the rectangular waveguide is known.

[0005] In the above-mentioned plasma generating section, a microwave oscillated from a magnetron provided in a microwave oscillator is introduced into a cylindrical waveguide through an isolator and a tuner provided in a rectangular waveguide, and this microwave is generated. , CFC (organic halogen compound) supplied to discharge tube
When irradiated with a mixture of / water vapor, thermal plasma is generated in the discharge tube.

Freon (CCl ₂ F ₂ ), which has been dissociated by the generation of thermal plasma, becomes water vapor (H) in the reaction tube.
₂ O) to react with hydrogen chloride (HCl), hydrogen fluoride (H
F) and carbon dioxide (CO ₂ ). The decomposition reaction at this time is as follows. CCl ₂ F ₂ + 2H ₂ O → 2HCl + 2HF + CO ₂

[0007]

The operation of the organic halogen compound decomposing apparatus having the above-described structure is controlled according to, for example, a time chart shown in FIG. That is,
When the operation preparation switch is turned on, first, air as scavenging gas and steam for co-washing are supplied into the apparatus system for a predetermined time, and then the ignition switch is turned on and supply of argon gas and steam is started. When the supply of the chlorofluorocarbon gas is started after a lapse of a predetermined time, the supply of the argon gas is stopped, and the state is shifted to a steady state.

[0008] However, the argon plasma is
Since the plasma flame 101 is extremely high at 000 to 6,000 ° K and the plasma flame 101 is wide as shown in FIG. 8, mist and droplets are generated in the steam at the time of transition from argon plasma to argon gas / steam plasma. If mixed, the behavior of the argon / water vapor plasma tends to be unstable, and the argon plasma is
There was a possibility that it would be inclined to the A side to cause the melting damage.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an apparatus for decomposing an organohalogen compound which can effectively prevent melting damage of a discharge tube when supplying steam, and an operation thereof. It is to provide a control method.

[0010]

Means for Solving the Problems In order to solve the above problems, the present invention employs the following means. The invention described in claim 1 is an organic halogen compound that generates thermal plasma by applying microwave energy to a gas containing an organic halogen compound, and decomposes the organic halogen compound by reacting it with water vapor in the thermal plasma. In the operation control method of the decomposition apparatus, after the rare gas supplied into the apparatus system is turned into plasma, and before the start of the supply of the water vapor that is executed prior to the start of the supply of the organic halogen compound,
It is characterized in that the supply of an assist gas for narrowing the plasma flame is started.

According to a second aspect of the present invention, in the operation control method for the organic halogen compound decomposing apparatus according to the first aspect, the supply of the rare gas which has been stopped after the start of the supply of the water vapor is supplied by the supply of the organic halogen compound. While restarting before the start, the supply of the assist gas is stopped.

According to a third aspect of the present invention, in the operation control method of the organic halogen compound decomposing apparatus according to the first or second aspect, the flow rate of the assist gas is set to 15 l / min.
It is characterized by the above. According to a fourth aspect of the present invention, in the operation control method of the organic halogen compound decomposing apparatus according to the first or second aspect, the flow rate of the assist gas is set to 30 m / s or more.

According to a fifth aspect of the present invention, a thermal plasma is generated by applying microwave energy to a gas containing an organic halogen compound, and the organic halogen compound reacts with water vapor in the thermal plasma to be decomposed. In the organic halogen compound decomposing device, the timing of starting / stopping the supply of the rare gas, the assist gas for narrowing the plasma flame, the water vapor, and the organic halogen compound into the device system, and the ignition timing of the rare gas are controlled. A control device, the control device permits the start of the supply of the rare gas, then permits the ignition of the rare gas to generate the thermal plasma, and executes the process prior to the start of the supply of the organic halogen compound. Before the start of the supply of the water vapor, the start of the supply of the assist gas is permitted.

According to a sixth aspect of the present invention, in the organic halogen compound decomposing apparatus according to the fifth aspect, the control device stops the supply of the rare gas which has been stopped after the start of the supply of the water vapor. It is characterized in that the supply of the assist gas is prohibited while the supply is permitted before the start of the supply.

According to a seventh aspect of the present invention, in the organic halogen compound decomposing apparatus according to the fifth or sixth aspect, the assist gas is supplied at a flow rate of 15 l / min or more. The invention according to claim 8 is the invention according to claim 5
Or the organic halogen compound decomposing apparatus according to 6, wherein the assist gas is supplied at a flow rate of 30 m / s or more.

According to the first and fifth aspects of the present invention, by introducing an assist gas in advance before introducing water vapor into the rare gas plasma, the plasma flame spread over substantially the entire area within the discharge tube. The shape of the plasma flame is narrowed (squeezed) toward the center of the discharge tube, so even if mist or droplets are mixed in the steam introduced afterward, the shape of the plasma flame is stable without swaying on the inner surface side of the discharge tube I do.

According to the second and sixth aspects of the present invention, the supply gas is switched from the assist gas to the rare gas at the stage when the supply of the steam is stabilized and the supply of the assist gas becomes unnecessary. Plasma misfire before the supply of the halogen compound is effectively prevented. In addition, depending on the components of the assist gas, undesirable gas such as NOx may be generated during the supply of the assist gas, but the generation of the gas is also prevented.

On the other hand, if the flow rate of the assist gas is too small, the behavior of the plasma flame becomes unstable, and there is a possibility that the discharge gas may come into contact with the discharge tube to cause melting. According to the third, fourth, seventh, and eighth aspects of the invention, since the amount of the assist gas is appropriate, the shape of the plasma flame is more stable.

[0019]

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 3, the rectangular waveguide 1 extending in the horizontal direction is provided with a microwave oscillator 2 for transmitting a microwave having a frequency of 2.45 GHz at the start end (left end), and from the start end to the end (right end). To transmit microwaves.

As shown in FIG. 1, the rectangular waveguide 1 prevents the reflected wave from affecting the transmitting side by absorbing the microwave reflected at the terminal end and returning to the starting end. An isolator 3 and a tuner 6 that adjusts the wave mismatch amount of the radio wave by moving a plurality of wave adjustment members 4 in and out respectively to converge the radio wave to the discharge tube 5 are provided.

This operation will be described in detail below. The microwave transmitter 2 is placed at one end of a rectangular waveguide 1 having a rectangular cross section, and drives a magnetron to emit an electromagnetic wave of a predetermined frequency. The characteristics of this propagation phenomenon of the electromagnetic wave can be grasped by solving Maxwell's wave equation relating to the electromagnetic wave. As a result, the electromagnetic wave propagates as an electromagnetic wave TE wave having no electric field component in the propagation direction.

[0022] shown in the propagation direction of the rectangular waveguide 1 of FIG. 2 an arrow direction an example of the first-order component TE ₁₀ alternates. The annular cavity of the double-cylindrical waveguide 7 formed of a double-cylindrical conductor at the other end of the rectangular waveguide 1 contains electromagnetic waves propagating through the rectangular waveguide 1 and electromagnetic waves reflected at the tube end. Due to the coupling action of the conductor 9, the annular cavity has a TM having an electric field component in the traveling direction.
Waves occur.

[0023] Similarly Figure 2 TM ₀₁ wave is the primary component
Are indicated by arrows. The fine adjustment caused by the second or higher harmonics related to the propagation of the electromagnetic wave is performed by the tuner 6.
It is adjusted by. The isolator 3 prevents the transmitter 2 from causing fundamental damage. As described above,
A stable electric field of mode TM ₀₁ is formed in the cylindrical waveguide 7.

As shown in FIG. 2, the cylindrical waveguide 7 includes an outer conductor 8 and an inner conductor 9 having a smaller diameter than the outer conductor 8. It is connected so that it may extend in the vertical direction while communicating with 1. The inner conductor 9 is fixed to the upper portion of the rectangular waveguide 1 and surrounds the discharge tube 5 made of quartz while enclosing the end plate 8 of the outer conductor 8.
A, and extend this portion to the probe antenna 9.
a.

The discharge tube 5 comprises an inner tube 11 and an outer tube 12, and is arranged so as to be coaxial with the central axis of the cylindrical waveguide 7. A Tesla coil 14 connected to an ignition device 13 is inserted into the inner tube 11 of the discharge tube 5, and the tip (lower end) of the inner tube 11 is connected to the probe antenna 9a.
Are disposed inward by a predetermined distance from the front end of the.

On the other hand, the tip of the outer tube 12 penetrates the end plate 8A of the outer conductor 8 and communicates with the copper reaction tube 15;
The proximal end (upper end) of the outer tube 12 is attached with a gap between the outer tube 12 and the inner conductor 9. Reference numeral 17 denotes an optical sensor directed to the outer cylinder 12 exposed between the end plate 8A of the outer conductor 8 and the reaction tube 15, and is provided for monitoring the state of plasma generation by detecting the luminous intensity. ing.

In the gap, a gas supply pipe 16 is provided.
It is inserted along the tangential direction at the inlet side of the annular passage formed by the inner pipe 2 and the inner pipe 11. Argon gas (rare gas), Freon gas (organic halogen compound), air (assist gas), and water vapor are shown in FIG.
The electromagnetic valves 19a, 19b, and 19c shown in FIG. 3 are selectively sent from respective supply sources to the heater 18, and then supplied from the gas supply pipe 16 to the annular passage of the discharge tube 5 through the mixer 37. You.

The argon gas is supplied for facilitating ignition prior to the generation of plasma, and is stored in the argon cylinder 21. Note that other rare gases such as helium and neon can be used instead of the argon gas. A pressure regulator 22 and a pressure switch 23 are provided between the argon cylinder 21 and the solenoid valve 19a.

The air removes the water remaining in the apparatus system to enhance the stability of ignition, and serves as a scavenging gas for discharging the gas remaining in the apparatus system.
The air is supplied from the air compressor 24 as an assist gas for narrowing (squeezing) the plasma flame 101 formed therein toward the center of the discharge tube 5. As the scavenging gas, air, nitrogen gas, argon gas, or the like is used. As the assist gas, plasma gas is less likely to be generated than argon gas, and although it depends on the operating conditions, it is difficult to misfire, for example, air or nitrogen. Nitrogen gas or the like is used.

Water vapor is necessary for decomposing the chlorofluorocarbon gas, and is generated by sending water in a water storage tank 26 to the heater 18 by a plunger pump 25. The water storage tank 26 is provided with a level switch 27 for detecting a change in water level.

The Freon gas is stored in liquid in a collected Freon cylinder 28, and the collected Freon cylinder 28 and the solenoid valve 1 are stored.
9b, the squeezing device 31, the mist separator 3
2, and a pressure switch 33 are provided. The throttle device 31 is provided to quantify the flow, and is constituted by, for example, a combination of a capillary tube and an orifice. The mist separator 32 is for removing oil (lubricating oil) and water contained in the CFC gas, and is of a collision type or a centrifugal type.

The heater 18 not only generates water vapor to be reacted with the chlorofluorocarbon gas, but also preheats the chlorofluorocarbon gas and the like, thereby avoiding the problem that the water vapor is cooled to the chlorofluorocarbon gas and recondensed in the apparatus system. The heating method such as an electric type or a steam type is adopted. The Freon gas or the like and the steam that have passed through the heater 18 are mixed in the mixer 37 and then supplied to the discharge tube 5 through the gas supply tube 16.

When microwave energy is supplied to the mixture supplied to the discharge tube 5, the electron energy in the discharge tube 5 is high, and furthermore, 5,000 ° to 6,000 °.
A thermal plasma enhanced to K is generated. Freon R12
In the case of (CCl ₂ F ₂ ), when the dissociation state occurs due to the generation of thermal plasma, water vapor H ₂ is generated in the reaction tube 5 of the decomposition reaction section C.
Reacts with O and is decomposed into hydrogen chloride HCl, hydrogen fluoride HF and carbon dioxide CO ₂ .

This decomposition reaction is represented by the following formula (1). CCl ₂ F ₂ + 2H ₂ O → 2HCl + 2HF + CO ₂ (1) In the case of Freon R22, the following reaction occurs. CHClF ₂ + H ₂ O → HCl + 2HF + CO (1a) In the case of Freon R134a, the following reaction takes place. CH ₂ FCF ₃ + H ₂ O → 4HF + CO + C (1b)

If the oxidation reaction of C in the formula (1) does not proceed sufficiently, or if the type of refrigerant (for example, CFC R in the formula (1a)
22 or H ₂ by Freon R134a) of the formula (1b)
With only O addition, carbon C burns incompletely and carbon monoxide CO
And free carbon C are produced. Therefore, the solenoid valve 19d is opened, air is supplied from the air compressor 51 to the reaction tube 15, and the air flows into the reaction tube 15 through the air pipe 52 to react (burn) with carbon monoxide. To produce carbon dioxide. CO + 1 / 2CO ₂ → CO ₂ (1c) C + O ₂ → CO ₂ (1d)

Both acidic gases of hydrogen chloride and hydrogen fluoride (corrosive gas generated as a result of the decomposition reaction) are supplied to an exhaust gas treatment section D.
In the exhaust gas treatment tank 41, neutralization is performed by a bubble column treatment method using slaked lime slurry. This neutralization reaction
It is represented by the following equations (2) and (3). 2HCl + Ca (OH) ₂ → CaCl ₂ + 2H ₂ O (2) 2HF + Ca (OH) ₂ → CaF ₂ + 2H ₂ O (3)

Calcium chloride (CaCl ₂ ) of the formula ( ₂ )
Is dissolved in water, but calcium fluoride (Ca) of the formula (3)
Since F ₂ ) has low solubility, it remains in the liquid as a solid. Therefore, the solid matter in the exhaust gas treatment tank 41 is received in the sedimentation tank 62 together with the alkali solution after the operation is stopped, and is separated into solid and liquid in the dehydration basket 63 and then disposed of as waste or used for other purposes. You. On the other hand, the separated alkaline liquid is returned to the exhaust gas treatment tank 41 again,
Reused or discarded.

In the organic halogen compound decomposing apparatus configured as described above, the opening and closing operations of the solenoid valves 19a to 19c,
The ignition operation of the Tesla coil 14 is controlled by the control device 61 as shown in the time chart of FIG. That is, when the operation switch is turned on, the solenoid valves 19a, 19b
Is closed to prohibit the supply of argon gas and chlorofluorocarbon gas, and open the solenoid valve 19c to permit the supply of air.
The air from the air compressor 24 is supplied to the gas supply pipe 16.
Is supplied to the discharge tube 5 for a predetermined time (for example, 6 minutes).

This air is heated to 100 to 180 ° C. by passing through the heater 18, so that the residual moisture in the apparatus system is reliably removed. Further, for a predetermined time (for example, 30 seconds) after the operation switch is turned on, the plunger pump 25 sucks the water in the water storage tank 26, passes the water through the heater 18, and performs the co-washing in the apparatus system with the steam generated. .

When the above operation preparation is completed, the solenoid valve 19
Close c to stop the air supply. Next, in order to improve the ignition stability, the electromagnetic valve 19a is opened to start supplying argon gas. Thereafter, the microwave is transmitted from the microwave oscillator 2 and a high voltage is applied to the Tesla coil 14 connected to the ignition device 13 to generate a spark discharge between the Tesla coil 14 and the inner conductor 9 to ignite.

When a predetermined time has elapsed from the start of the supply of the argon gas, the solenoid valve 19c is opened and the air compressor 24 is operated to restart the supply of the air. The air has a flow rate of 15 l / min or more and a flow rate of 30 m / s or more. A predetermined time (for example, 0.5
After the elapse of (seconds), water is sucked from the water storage tank 26 by the plunger pump 25, and the water is drawn through the heater 18 to start supplying the generated steam to the discharge tube 5.

As described above, if a specified amount of air is introduced before starting the supply of water vapor, the shape of the plasma flame 101 that has spread over substantially the entire area of the discharge tube 5 is changed to the center of the discharge tube 5. It is narrowed (squeezed) toward the part. FIG. 5 shows a state in which the air flow rate was variously changed. As can be seen from the figure, when the air supply amount is about 15 l / min or more, the fluctuation time of the plasma flame 101 (plasma flame 1
It is understood that the plasma flame 101 is stabilized (time required for the plasma flame 101 to come into contact with the discharge tube 5) is extremely short (less than 0.1 second). For this reason, the shape of the plasma flame 101 may fluctuate on the inner surface side of the discharge tube 5 even if mist or droplets are mixed in the steam because the heating by the heater 18 is insufficient or uneven. The discharge tube 5 is effectively stabilized without melting.

For a predetermined time (eg,
When 0.5 seconds have elapsed, the solenoid valve 19a is closed and the supply of the argon gas is stopped for a predetermined time. After a predetermined time, the solenoid valve 19a is opened to restart the supply of the argon gas, and after a lapse of a predetermined time (for example, 15 seconds) from the restart of the supply of the air, the solenoid valve 19c is closed to stop the air supply. 19b is opened to start supply of Freon gas.

When the operation switch is turned on after a lapse of a predetermined time from the start of the supply of the chlorofluorocarbon gas, the solenoid valve 19a is closed to stop the supply of the argon gas, and the operation shifts to a steady operation.
As described above, before the supply of the CFC gas is started, the supply of the argon gas which has been temporarily stopped after the supply of the steam is restarted, while the supply of the air is stopped simultaneously with the start of the supply of the CFC gas, the plasma misfire may occur. This is more reliably prevented, and the generation of NOx can be effectively avoided.

It should be noted that the present invention is not limited to the above-described embodiment, and the specific numerical values described above are merely examples, and the present invention is not limited to these. For example, in the above-described embodiment, as shown in FIG. 4, the supply of the argon gas is restarted when the fluorocarbon gas is supplied. However, as shown in FIG. 6, the operation control method does not restart the supply of the argon gas. In this case, the consumption of argon gas can be reduced.

Here, the difference between the operation patterns shown in FIGS. 4 and 6 will be supplementarily described. In the operation pattern of FIG. 4, even if the air flow rate immediately after the start of the supply of the chlorofluorocarbon gas is zero, the argon gas is lit, so that continuous operation is possible by adjusting the flow rate of the chlorofluorocarbon gas.

On the other hand, in the operation pattern shown in FIG. 6, the CFC is supplied into the air / steam plasma flame, and thereafter, the plasma is switched to the CFC / steam plasma. If the Freon gas supply is initially set to zero,
The plasma disappears at the same time as the air supply is stopped, and there is a drawback that the system must be restarted from the initial system state. However, prior to the supply of CFC gas, an assist gas (for example, air) is supplied to adjust the plasma flame. The point is that the essence remains.

[0048]

As is apparent from the above description, according to the present invention, the following effects can be obtained. (1) According to the first and fifth aspects of the present invention, by introducing an assist gas in advance before introducing water vapor into the rare gas plasma, the plasma has been spread over substantially the entire area in the discharge tube. Since the shape of the flame is narrowed (squeezed) toward the center of the discharge tube, the shape of the plasma flame does not fluctuate on the inner surface of the discharge tube even if mist or droplets are mixed in the steam introduced afterward. It is stable and can effectively avoid melting damage of the discharge tube.

(2) According to the second and sixth aspects of the present invention, when the supply of the assist gas becomes unnecessary,
By switching the supply gas from the assist gas to the rare gas, it is possible to effectively prevent plasma misfire before the supply of the organic halogen compound, thereby stabilizing the decomposition reaction and, depending on the components of the assist gas,
Even in the case where an undesirable gas such as x can be generated, the generation of the gas is also effectively prevented, whereby the detoxification treatment after the decomposition reaction is more thorough.

(3) According to the third, fourth, seventh, and eighth aspects of the invention, since the amount of the assist gas is appropriate, the shape of the plasma flame can be further stabilized. it can. For this reason, melting damage of the discharge tube can be prevented, and the stability of the system is improved.

[Brief description of the drawings]

FIG. 1 is a system diagram showing an embodiment of an organic halogen compound decomposing apparatus according to the present invention.

FIG. 2 is an enlarged view of a main part of the decomposition apparatus.

FIG. 3 is a perspective view showing an entire configuration of the disassembling apparatus.

FIG. 4 is a time chart showing an embodiment of an operation control method according to the present invention.

FIG. 5 is a diagram showing a fluctuation time of a plasma flame when an air supply amount is variously changed.

FIG. 6 is a time chart showing another embodiment of the operation control method according to the present invention.

FIG. 7 is a time chart showing a conventional example of an operation control method of an organic halogen compound decomposition apparatus.

8 is an enlarged sectional view of a main part of an organic halogen compound decomposing apparatus showing a state of a plasma flame formed by the operation control method shown in FIG.

[Explanation of symbols]

 5 Discharge Tube 13 Ignition Device 14 Tesla Coil 18 Heater 19a, 19b, 19c Solenoid Valve 21 Argon Cylinder 24 Air Compressor 25 Plunger Pump 26 Water Storage Tank 28 Collection Freon Cylinder 61 Controller 101 Plasma Flame

Continuation of the front page (72) Inventor Masahiro Bessho 1 Nagoya Research Center, Nagoya-shi, Aichi Prefecture, Nagoya Research Laboratories 1 Address: Nagoya Laboratory, Mitsubishi Heavy Industries, Ltd. (72) Inventor Harunobu Mizukami 1 Takamichi, Iwazuka-cho, Nakamura-ku, Nagoya-shi, Aichi Japan No. 6-22, Mitsubishi Heavy Industries, Ltd. Hiroshima Research Laboratory (72) Inventor Takataka Hasegawa 60-1, Kutsubo, Iwazuka-cho, Nakamura-ku, Nagoya-shi, Aichi F-term (reference) 2C191 BB00 BC01 BD18 4G075 AA03 AA37 AA42 AA62 BA01 BA05 CA26 CA48 CA51 CA63 DA02 DA05 EB21 ED08 4H006 AA04 AA05 AC13 AC26 BA95

Claims (8)

[Claims] 1. An operation of an organic halogen compound decomposing apparatus which generates thermal plasma by applying microwave energy to a gas containing an organic halogen compound and reacts and decomposes an organic halogen compound with water vapor in the thermal plasma. In the control method, after the rare gas supplied into the apparatus system is turned into plasma and before the start of the supply of the water vapor, which is executed prior to the start of the supply of the organic halogen compound, supply of an assist gas for narrowing a plasma flame The method for controlling the operation of an organic halogen compound decomposing apparatus, characterized in that: 2. The supply of the rare gas, which has been stopped after the start of the supply of the steam, is restarted before the start of the supply of the organic halogen compound, and the supply of the assist gas is stopped. An operation control method for the organic halogen compound decomposer according to claim 1. 3. The operation control method for an organic halogen compound decomposition apparatus according to claim 1, wherein the flow rate of the assist gas is set to 15 l / min or more. . 4. The operation control method for an organic halogen compound decomposition apparatus according to claim 1, wherein the flow rate of the assist gas is 30 m / s or more. . 5. An organic halogen compound decomposer for generating thermal plasma by applying microwave energy to a gas containing an organic halogen compound and reacting the organic halogen compound with water vapor in the thermal plasma to decompose the gas. A rare gas, an assist gas for narrowing the plasma flame, the water vapor,
And supply of the organic halogen compound into the apparatus system /
A control device for controlling a stop time and an ignition timing for the rare gas, wherein the control device permits the start of the rare gas supply, and then permits the ignition to the rare gas to perform the thermal plasma. An organic halogen compound decomposing apparatus, wherein the start of the supply of the assist gas is permitted before the start of the supply of the water vapor is executed prior to the permission of the start of the supply of the organic halogen compound. 6. The control device according to claim 1, wherein the supply of the rare gas, which has been stopped after the start of the supply of the steam, is permitted before the start of the supply of the organic halogen compound, and the supply of the assist gas is prohibited. An apparatus for decomposing an organic halogen compound according to claim 5. 7. The organic halogen compound decomposer according to claim 5, wherein the assist gas is supplied at a flow rate of 15 l / min or more. 8. The organic halogen compound decomposer according to claim 5, wherein the assist gas is supplied at a flow rate of 30 m / s or more.