JPH0780286A - Organohalogen compound decomposition apparatus using high frequency induction heating plasma device - Google Patents

Abstract

PURPOSE:To realize an organohalogen compd. decomposing apparatus using a high frequency induction heating plasma device eliminating the necessary of heating the introducing piping of a substance to be decomposed to high temp. and capable of preventing the condensation of the substance to be decomposed and the abnormal pressurization in the piping. CONSTITUTION:After steam plasma P is generated in a pipe 21 and a chamber 23, a valve 32 is opened and argon gas is supplied into a container 34 from an argon cylinder 35 to push out the chlorofluorocarbon liquid in the container 34 and the chlorofluorocarbon liquid is supplied into the steam plasma P through the orifice 29 of a probe 30 in a liquid state. As a result, chlorofluorocarbon and steam are decomposed into an atomic/molecular state by hot plasma of 10000 deg.C or higher to be converted to carbon dioxide or acidic gas in a cooling process. Thereafter, carbon dioxide is discharged as it is and the acidic gas is neutralized with the alkali aq. soln. 16 in a container 17 to be converted to a non-pollution substance such as salt to be discharged or fluorine is recovered from the acidic gas to be reutilized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high frequency induction plasma apparatus for supplying a gas having an appropriate pressure into a tube and supplying a high frequency to an induction coil arranged outside the tube to generate plasma in the tube. The present invention relates to an apparatus for decomposing organic halogen compounds using a high-frequency induction thermal plasma device that decomposes the organic halogen compounds by using.

[0002]

2. Description of the Related Art FIG. 1 shows an apparatus for decomposing an organic halogen compound such as CFC using a high frequency induction plasma apparatus disclosed in, for example, Japanese Patent Laid-Open No. 3-90172. The induction plasma torch 1 is made of quartz. It is composed of a cylindrical tube 2 formed of an insulating material such as, a gas ring 3, an induction coil 4 wound around the tube 2, and the like.
A ring-shaped groove 5 is formed in the gas ring 3, and a ring-shaped plate 6 is welded to the outside of the groove 5.
A large number of minute holes 7 are bored in the ring-shaped plate 6, and one end of a hole 8 bored inside the gas ring 3 is connected to the groove 5. The other end of the hole 8 is connected to the pipe 9 at the upper part of the gas ring 3.

The pipe 9 is branched in the middle, one of which is the first
Inside the container 110, and the other inside the second container 111. In the first container 110, a liquid organohalogen compound 11 such as CFC 113 to be decomposed.
2 is included. One end of a carrier gas supply pipe 113 is inserted in the organic halogen compound in the first container 110. The other end of the carrier gas supply pipe 113 is
Argon gas source 1 via flow controller 114
It is connected to 15. In the second container 111, water 1
16 is put therein, and one end of a carrier gas supply pipe 117 is inserted into this water 116. The other end of the carrier gas supply pipe 117 has a flow controller 118.
It is connected to the argon gas source 115 via.

A switching bubble 119 is provided in the middle of the tube 9. The switching valve 119 switches between the gas from the first container 110 and the second container 111 and the gas from the argon gas source 14 to guide the gas to the hole 8 formed in the gas ring 3. The gas flow rate from the argon gas source 14 is controlled by the flow controller 121.

A cylindrical tube 2 constituting a plasma torch 1.
An opening 122 is provided in the lower part of the opening 12.
An exhaust pipe 123 is connected to 2. Exhaust pipe 123
Is connected to a cyclone 124 that traps powdered material contained in the exhausted gas. The exhaust gas that has passed through the cyclone 124 is guided to a pipe 125, which is introduced into a container 17 in which an alkaline aqueous solution, for example, potassium hydroxide (KOH) 16 is contained. A discharge pipe 128 for the internal gas is provided in the upper part of the container 17, and the discharge pipe 128 has an alkaline solid, such as calcium oxide (CaO), inside.
It is connected to the lower portion of the container 130 containing 129. At the top of the container 130, the calcium oxide 12
An exhaust pipe 131 for the gas that has passed between 9 is provided.

The operation of the apparatus configured as above will be described below. In the initial state of the apparatus, the switching valve 119 provided in the middle of the pipe 9 is operated so that the argon gas from the argon gas source 14 is supplied into the groove 5 through the hole 8 of the gas ring 3. . By supplying the argon gas to the groove 5, the argon gas is supplied to the plate 6
It is ejected into the cylindrical tube 2 from a large number of minute holes 7 provided in the. In this state, high frequency is supplied to the induction coil 4 and the plasma P is ignited by an ignition mechanism (not shown).

After that, the switching valve 119 is switched to replace the argon gas from the argon gas source 14 with the gas from the first container 110 and the gas from the second container 111 into the groove 5 through the hole 8 of the gas ring 3. To be supplied. In the first container 110, the internal organic halogen compound solution 1
In FIG. 12, a carrier gas supply pipe 113 connected to an argon gas source 115 is inserted, and an appropriate flow rate is set by a flow controller 114 from the end of the pipe 113 opened in the organohalogen compound 112. Argon gas is ejected. As a result, the organohalogen compound becomes vapor by the bubbling of the argon gas, is contained in the gas, and is discharged from the inside of the first container 110 into the pipe 9. Further, in the second container 111, a carrier gas supply pipe 117 connected to an argon gas source 115 is inserted into water 116 inside, and the water 11
From the end of the pipe 117 opened into the inside of the chamber 6, argon gas is jetted at an appropriate flow rate by the flow controller 118. As a result, the water is vaporized by the bubbling of the argon gas, contained in the gas, and discharged from the inside of the first container 111 into the pipe 9.

At a branch portion J in the middle of the pipe 9, an argon gas containing a vapor of an organic halogen compound and an argon gas containing a water vapor are mixed, and the mixed gas is a hole 8 of the gas ring 3.
Is introduced into the groove 5 via. From the groove 5, the mixed gas
It is ejected into the tube 2 through a large number of minute holes 7 provided in the plate 6 and introduced into the plasma flame P. At this time, the temperature of the plasma is 10,000 to 15,000, and the organic halogen compound and water introduced into the plasma flame P are decomposed at high temperature with high efficiency and undergo the chemical reaction shown below. To do.

Trichlorofur as an organic halogen compound
Oromethane (CFC-11 ... CCl ₃F) in plasma
When decomposed with, the following reaction occurs with water. CCl₃F + 2H₂O = CO₂+ 3HCl + HF The exhaust gas containing the decomposed molecules is discharged through the opening 1 at the bottom of the tube 2.
22 through the discharge pipe 123 into the cyclone 124
Be guided. At this time, there is less water than CFC-11
Produces excess carbon, but within this cyclone 124,
Fine powder such as carbon contained in the exhaust gas is trapped.
Be done. The gas that has passed through the cyclone 124 is from the pipe 125.
It is introduced into the potassium hydroxide aqueous solution 16 inside the container 17.
Be done. By passing the exhaust gas through this solution 16,
Exhaust gas containing acids such as HCl and HF is neutralized. Neutralization
The generated gas passes through the discharge pipe 128 from the bottom of the container 126.
Then, the acid inside the container 130 is introduced into the container 130.
It is dehydrated by calcium chloride 129. Dehydrated moth
Is a stable, environmentally friendly compound.
Yes, it is released into the atmosphere as appropriate.

[0010]

The decomposition method of the organic halogen compound using the above high frequency induction plasma apparatus is as follows.
When decomposing a low boiling point substance such as Freon 12 (boiling point ... 29.8 ° C.), it is a convenient method because gasification is easy. However, Freon 113 (boiling point ... 47.5
C.) and polychlorinated biphenyls (PCBs) have problems in gasifying substances with boiling points of hundreds of degrees. That is, since these substances are not vaporized by bubbling, a separate heating means must be provided to vaporize them, and if the temperature of the pipe 9 or the gas ring 3 through which the substance to be decomposed passes is low, the substance to be decomposed and steam The substance is condensed in the pipe and the gas ring due to the mixing with the, and in the worst case, sludge is accumulated in the pipe 9 and causes the pipe 9 to be clogged. When the condensed aqueous solution of CFCs is atomized and supplied into the plasma in the tube 2, not only the plasma becomes very unstable, but also the condensed aqueous solution of CFCs is discharged without being decomposed. There is also a problem that Therefore, it becomes necessary to heat the pipe 9 portion to which the fluorocarbon solution is supplied to a high temperature all over,
It is difficult to heat the pipe 9 such as the joint part of the pipe 9 and the seal part of the gas ring, and it is impossible to heat the pipe 9 to a high temperature so that the substance to be decomposed is not condensed. I don't get it.

Further, as another problem, when the steam and the substance to be decomposed such as CFC are supplied through the same pipe 9,
First, since the internal pressure in the pipe 9 is increased by a large amount of steam, in order to supply the substance to be decomposed into the steam in the pipe, the pressure of the substance to be supplied needs to be higher than the pressure of the steam. . Therefore, if it is attempted to supply a large amount of both steam and the substance to be decomposed, it is necessary to pressurize each other abnormally, and in some cases, a dangerous state such as pipe explosion may occur.

The present invention has been made in view of the above points, and an object thereof is not to require high temperature heating of a pipe for introducing a substance to be decomposed, condensation of the substance to be decomposed, and abnormality inside the pipe. Another object of the present invention is to realize an apparatus for decomposing organic halogen compounds using a high frequency induction thermal plasma apparatus capable of preventing various pressurizations.

[0013]

An apparatus for decomposing an organohalogen compound using a high frequency induction thermal plasma apparatus according to the present invention comprises a tube to which a plasma generating gas is supplied from one end,
A high-frequency induction coil arranged outside the tube is provided, and a substance to be decomposed and water vapor are supplied to a high-frequency induction plasma device that generates plasma in the tube, and the substance is decomposed in the plasma. In an apparatus for decomposing organic halogen compounds using a high-frequency induction thermal plasma device, water vapor and a substance to be decomposed are introduced into the high-frequency induction plasma device through different routes, and the plasma generation direction in the high-frequency induction plasma device is set to a level higher than the horizontal The feature is that it is facing upward.

[0014]

The apparatus for decomposing an organohalogen compound using the high frequency induction thermal plasma apparatus according to the present invention guides the vapor and the substance to be decomposed into the high frequency induction plasma apparatus through different routes, and at the same time, reduces the plasma in the high frequency induction plasma apparatus. The direction of occurrence is upward from the horizontal direction.

[0015]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 2 shows an apparatus for decomposing organic halogen compounds according to the present invention, and the same or similar elements as those of the conventional apparatus shown in FIG. 1 are designated by the same reference numerals. In this embodiment, a gas ring 22 is provided at the bottom of the ceramic tube 21, and a chamber 23 made of heat-resistant and corrosion-resistant brick is arranged above the tube 21. A ring-shaped passage 24 is provided in the outer peripheral portion of the gas ring 22, and the passage 24 is connected to a pipe 26 through a hole 25. The pipe 26 is connected to the steam boiler 10 via a valve 27.
Is also connected to the argon gas cylinder 14 via a valve 28. 19 is a gas ring 22
And a conductive member (not shown) provided in the lower part of the chamber 23 is a high voltage generator.

A probe 30 having a hole 29 is provided at the center of the gas ring 22, and the opening of the hole 29 facing the tube 21 has a nozzle shape. Further, the hole 29 is connected to the insulating tube 31, but the tube 31
Is connected via a valve 32 to a container 34 containing a liquid 33 to be decomposed such as CFC. Argon gas is supplied from the argon gas cylinder 35 into the container 34. The container 34 is also mounted on a weight control system 36. The upper portion of the chamber 23 is connected via a pipe 37 to a container 17 containing the alkaline aqueous solution 16. The alkaline aqueous solution in the container 17 is flowed by the pump 38 through the circulation path 39 to a middle portion of the chamber 23. The operation of such a configuration will be described below.

First, steam in the steam boiler 10, the piping line 26, the gas ring 22 and the probe 30 are sufficiently heated to a temperature above the condensation temperature of water. Further, the container 34 containing the liquid 33 to be decomposed such as CFC and the probe 3
0 is connected using an insulating tube 31. At this time, it is preferable to cool the insulating tube 31 so that it is not transferred by the heated probe 30.
Next, all the valves 27, 28 and 32 are closed, and the inside of the chamber 23 is set to 200 To via the exhaust pipe 18 and the container 17.
Reduce the pressure to about rr.

After the pressure in the chamber 23 becomes constant, the valve 28 is opened and the ignition argon gas is introduced into the pipe 21 through the hole 25 of the gas ring 22 and the passage 24. After that, a high-frequency current is supplied to the induction coil 4 from a high-frequency oscillator (not shown) to supply a strong magnetic field into the tube 21. Further, at this time, the gas ring 22 and the chamber 23
An initial trigger is applied from the high-voltage generator 19 to a conductive member (not shown) provided in the lower part of the column to excite the argon gas and start plasma. At this time, it is desirable to perform automatic control so that the pressure in the chamber 23 is always constant.

Next, the high frequency power supplied to the induction coil 4 is increased, and at the same time, the valve 27 is opened to gradually increase the water vapor and supply the water vapor into the pipe 21. Contrary to the supply of water vapor, the valve 28 is gradually closed, and finally argon gas is replaced with water vapor to completely close the valve 28. As a result, 100% of steam plasma P
Can be generated. Also at this time, it is desirable to perform automatic control so that the pressure in the chamber 23 is always constant.

As mentioned above, the tube 21 and the chamber 23
After the water vapor plasma P is generated inside, the valve 32 is opened, and argon gas is supplied from the argon gas cylinder 35 into the container 34 to push out the CFC liquid inside the container 34, and the liquid C It is supplied as it is into the steam plasma. As a result, Freon and water vapor,
Decomposed into atoms and molecules by thermal plasma of 10,000 degrees,
Then, it is converted into carbon dioxide gas or acid gas in the cooling process. After that, the carbon dioxide gas is discharged as it is, and the acidic gas is neutralized with the alkaline aqueous solution 16 in the container 17 to be converted into a non-polluting substance such as salt, and is drained or fluorine is recovered for reuse. The amount of CFCs to be decomposed is controlled by constantly monitoring the amount of CFC change by the weight control system 36 and controlling the valve 32 and the amount of Ar gas. Further, the alkaline aqueous solution in the container 17 is guided to a middle portion of the chamber 23 by the pump 38 so that the inner wall of the chamber 23 is not corroded by the acid gas.
It is sprayed on the inner wall of the chamber 23.

As described above, in the above-described embodiment, the high-frequency induction thermal plasma apparatus is supplied with the steam and the CFCs to be decomposed through different paths, so that the steam pressure is increased. It is not necessary to abnormally increase the pressure of substances such as CFCs, and substances such as CFCs can be easily supplied into the thermal plasma device, and explosion of tubes and the like can be prevented. Further, since the substance to be decomposed such as CFC is not vaporized in advance and is supplied as liquid into the plasma, it is not necessary to heat the pipe of the substance to be decomposed to a high temperature, and the liquid amount can be easily controlled. be able to.

Further, in the type in which the substance to be decomposed or the like is supplied from above the thermal plasma device as in the conventional apparatus of FIG. 1, when the liquid substance to be decomposed is directly supplied to the plasma, the substance to be decomposed is not decomposed. There is a risk that chlorofluorocarbon, which has not been decomposed, may be discharged to the outside by dripping downward in this state. For this reason, in the above-described embodiment, water vapor and CFCs to be decomposed are supplied from the lower side of the thermal plasma device, and liquid CFCs are not dropped downwards by this, and thus undecomposed by mistake. The discharge of this substance is prevented.

FIG. 3 shows the essential parts of another embodiment of the present invention. In this embodiment, the same or similar parts as in the embodiment of FIG. 2 are designated by the same reference numerals. The difference between this embodiment and the embodiment of FIG. 2 is that in the embodiment of FIG. 2, water vapor or a substance to be decomposed is supplied from below in the induction thermal plasma device,
While the thermal plasma is generated upward,
In the embodiment of FIG. 3, water vapor or a substance to be decomposed is supplied in the lateral direction, and the thermal plasma P is generated in the lateral direction (horizontal direction). Even if the plasma is generated in the lateral direction, the risk of accidentally discharging the undecomposed substance is prevented.

Although the embodiment of the present invention has been described above, the present invention is not limited to this embodiment. For example, in the embodiment of FIG. 2, plasma was generated vertically from below to above, and in the embodiment of FIG. 3, plasma was generated horizontally, but in any direction between vertical and horizontal. You may let me.

[0025]

As described above, the apparatus for decomposing organic halogen compounds using the high frequency induction thermal plasma apparatus according to the present invention guides the water vapor and the substance to be decomposed into the high frequency induction plasma apparatus by different routes. At the same time, since the plasma generation direction in the high frequency induction plasma device is upward in the horizontal direction or more, it is not necessary to heat the introduction path of the substance to be decomposed to an abnormally high temperature. Further, it is possible to prevent condensation of the substance to be decomposed and abnormal pressurization inside the pipe. Further, even if the liquid substance to be decomposed is directly introduced into the plasma, the substance is prevented from being discharged without being decomposed.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of an apparatus for decomposing an organic halogen compound using a conventional high frequency induction thermal plasma apparatus.

FIG. 2 is a diagram showing an apparatus for decomposing an organic halogen compound using a high frequency induction thermal plasma apparatus which is an embodiment of the present invention.

FIG. 3 is a view showing a main part of an apparatus for decomposing an organic halogen compound using a high frequency induction thermal plasma apparatus which is another embodiment of the present invention.

[Explanation of symbols]

 21 pipe 22 gas ring 23 chamber 24 induction coil 25 hole 26 pipe 29 hole 30 probe 31 insulating tube 33 decomposed liquid 34 container 35 gas cylinder 36 weight control system

 ─────────────────────────────────────────────────── ─── Continuation of front page (71) Applicant 000006655 Nippon Steel Co., Ltd. 2-3-6 Otemachi, Chiyoda-ku, Tokyo (71) Applicant 000004271 Nihon Denshi Co., Ltd. 3-1-1 Musashino, Akishima-shi, Tokyo No. 2 (74) Attorney-at-law, Fujiharu Ijima (one outside) (72) Inventor Koichi Mizuno 16-3 Onogawa, Tsukuba-shi, Ibaraki Institute of Industrial Science and Technology (72) Inventor Univ. Uchihideo 16-3 Onogawa, Tsukuba-shi, Ibaraki Institute of Advanced Industrial Science and Technology (72) Inventor Toyonobu Yoshida 7-3-1, Hongo, Bunkyo-ku, Tokyo Tokyo University (72) Inventor Asakura Tomomi 1-3-1, Uchisaiwaicho, Chiyoda-ku, Tokyo Within Tokyo Electric Power Company (72) Nobuyuki Uematsu 2-chome, Otemachi, Chiyoda-ku, Tokyo Ban No. 3 Shin Nippon Steel within Co., Ltd. (72) inventor Hisashi Komaki Akishima, Tokyo Musashino 3-chome No. 1 No. 2 Japan in the Electronics Co., Ltd.

Claims (1)

[Claims] 1. A high-frequency induction thermal plasma device, comprising a tube to which a plasma-generating gas is supplied from one end and a high-frequency induction coil arranged outside the tube, to generate plasma inside the tube. Supply substances and water vapor,
In an apparatus for decomposing an organohalogen compound using a high frequency induction thermal plasma device adapted to decompose the substance in plasma, water vapor and the substance to be decomposed are introduced into the high frequency induction plasma device through different routes, and the high frequency induction plasma An apparatus for decomposing an organohalogen compound using a high-frequency induction thermal plasma apparatus, characterized in that the plasma generation direction in the apparatus is horizontal and upward.