JP2003144844A - Decomposing equipment for organic halogen compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent clogging at the front end of a blow pipe. SOLUTION: A decomposing equipment for an organic halogen compound is furnished with a waste gas treating tank 41 for housing an alkaline liquid, the blow pipe 145 installed in the state of immersing the opened front end 145a into the alkaline liquid and a reaction pipe 15 which is connected to the blow pipe 145, is fed with the organic halogen compound to be decomposed and decomposes the organic halogen compound by electric discharge, in which the front end 145a of the blow pipe 145 is formed to a convergent shape.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for decomposing organic halogen compounds using plasma discharge, and in particular,
The present invention relates to an apparatus for decomposing organic halogen compounds, which is configured to generate plasma using microwaves.

[0002]

2. Description of the Related Art Organic halogen compounds such as CFCs containing fluorine, chlorine, bromine, etc. in the molecule, trichloromethane, halon, etc. are widely used in a wide variety of applications such as refrigerants, solvents, fire extinguishing agents, etc. Is extremely important.
However, since these compounds are highly volatile, if they are left untreated in the environment such as air, soil, and water, they may adversely affect the environment, such as the formation of carcinogens and the destruction of the ozone layer. , It is necessary to detoxify from the viewpoint of environmental protection.

[0003] Conventionally, a method of treating an organic halogen compound has been reported mainly utilizing a decomposition reaction at a high temperature, and this treating method is roughly classified into an incineration method and a plasma method. In the incineration method, organic halogen compounds are incinerated in a cement kiln or rotary kiln, whereas in the plasma method, organic halogen compounds are reacted with water vapor in plasma and decomposed into carbon dioxide, hydrogen chloride, and hydrogen fluoride. To do.

Further, regarding the latter decomposition apparatus for an organic halogen compound according to the plasma method, one that uses microwaves to generate plasma has been developed in recent years. This decomposition apparatus comprises an exhaust gas treatment tank containing an alkaline solution, a reaction tube arranged with its open lower end immersed in the alkaline solution, and a cylindrical waveguide extending vertically above the reaction tube. A tube, a discharge tube disposed inside the cylindrical waveguide and penetrating the lower end thereof to communicate with the reaction tube, and a rectangular waveguide extending in the horizontal direction and connected to the cylindrical waveguide in the vicinity of one end thereof. It is provided with a tube and a microwave oscillator mounted on the other end of the rectangular waveguide.

In this decomposition apparatus, while the Freon gas and water vapor are supplied to the discharge tube, the microwave emitted from the microwave oscillator is transmitted to the cylindrical waveguide through the rectangular waveguide. Then, electric discharge is caused by the microwave electric field formed inside the cylindrical waveguide, and CFC gas is decomposed by thermal plasma in the reaction tube. On the other hand, the generated gas generated by this decomposition reaction is neutralized by passing through the alkaline liquid, and the remaining gas containing carbon dioxide gas and the like is discharged from the exhaust duct.

An example of such a decomposition device for an organic halogen compound using plasma discharge is introduced in Japanese Patent Laid-Open No. 2000-296313 by the present applicant.

FIG. 1 is a view described in the above publication, and in this decomposition apparatus for an organic halogen compound, an exhaust gas treatment tank 41 containing an alkaline liquid and an open tip portion are installed in a state of being immersed in the alkaline liquid. A blow tube 45 and a reaction tube 15 connected to the blow tube 45 and supplied with an organohalogen compound to be decomposed to decompose the organohalogen compound by discharge are provided.

[0008]

In the apparatus for decomposing an organohalogen compound having such a structure, as shown in FIG. 2, there is a problem that clogging 45b easily occurs inside the tip end portion 45a of the blow-in pipe 45. there were. This is because (1) the tip portion 45a is bent at about 30 ° from the horizontal plane, and thus it is difficult for the accumulated matter to fall due to gravity, (2)
Since the gas ejection speed from the tip portion 45a is about 3 to 4 m / s, the slurry stored in the exhaust gas treatment tank 41 instantaneously enters the tip portion 45a (splash back phenomenon), and the sticking in the slurry occurs. 45a
Adheres to the inner surface of the tip portion 45a, and (3) during operation suspension, the slurry enters the blow-in tube 45 including the tip portion 45a, and the sticky substance in the slurry adheres to the inner surface of the tip portion 45a. Is. Therefore, the tip 45 is frequently used.
It was necessary to perform maintenance of a.

The present invention has been made in view of the above problems in the prior art, and an object of the present invention is to provide an apparatus for decomposing an organohalogen compound capable of preventing clogging of the tip portion of a blow tube.

[0010]

A decomposition apparatus for an organic halogen compound according to claim 1, wherein the decomposition apparatus is a decomposition apparatus for an organic halogen compound, wherein an exhaust gas treatment tank for containing an alkaline solution and an open end portion are provided with the alkali. A blowing pipe installed in a state of being immersed in the liquid, a reaction pipe connected to the blowing pipe and supplied with an organic halogen compound to be decomposed, and decomposing the organic halogen compound by discharge,
And the tip portion of the blow-in tube is tapered. The apparatus for decomposing an organic halogen compound according to claim 2, wherein the apparatus is an apparatus for decomposing an organic halogen compound, the exhaust gas treatment tank containing an alkaline liquid, and the open tip end portion being immersed in the alkaline liquid. A blow tube, and a reaction tube connected to the blow tube and supplied with an organohalogen compound to be decomposed to decompose the organohalogen compound by discharge, at the tip of the blow tube. ,
The feature is that it is non-adhesive processed. In the apparatus for decomposing an organic halogen compound according to claim 3, in the apparatus for decomposing an organic halogen compound according to claim 2, the non-adhesive processing is fluororesin processing. The organic halogen compound decomposing apparatus according to claim 4, wherein the organic halogen compound decomposing apparatus comprises an exhaust gas treatment tank containing an alkaline liquid,
A blow-in pipe installed with the open tip immersed in the alkaline solution, and a reaction pipe connected to the blow-in pipe and supplied with an organic halogen compound to be decomposed to decompose the organic halogen compound by discharge. And an air supply mechanism for supplying purge gas to the blow-in pipe when the operation of the decomposition apparatus is stopped. The organic halogen compound decomposing apparatus according to claim 5 is characterized in that, in the organic halogen compound decomposing apparatus according to any one of claims 1 to 4, a pressure sensor is installed upstream of the blow-in pipe. I am trying. The organohalogen compound decomposing apparatus according to claim 6, wherein in the organohalogen compound decomposing apparatus according to any one of claims 1 to 5, the tip end portion of the blow pipe is inclined by 60 ° or more from the horizontal direction. It is characterized by being said.

According to the first aspect of the present invention, since the tip portion of the blow-in pipe is tapered, the gas flow velocity from the tip portion is increased, and the slurry is momentarily introduced (splash back phenomenon). Is prevented and clogging of the inner surface of the tip is prevented. In the invention of claim 2 or 3, since the tip portion of the blow-in pipe is subjected to non-adhesive processing such as fluororesin processing, the sticky substance is unlikely to adhere to the inner surface of the tip portion. Even if it adheres on top, it can be easily removed. According to the invention of claim 4, the purge gas is fed to the blow-in pipe when the operation of the decomposition device of the organic halogen compound is stopped by the air supply mechanism, so that the slurry enters into the tip portion when the operation is stopped. There is no. In the invention according to claim 5, since the pressure sensor is installed on the upstream side of the blow-in pipe, it is possible to constantly monitor the occurrence of clogging of the tip end portion.
According to the invention of claim 6, the tip end portion of the blow-in pipe is inclined by 60 ° or more from the horizontal direction,
Even if deposits are formed, they easily fall due to gravity.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of an apparatus for decomposing organic halogen compounds according to the present invention will be described below with reference to the drawings.

First, prior to the detailed description of the present invention, the conventional apparatus for decomposing an organic halogen compound will be schematically described by taking an example of decomposing a CFC gas as an example of an organic halogen compound.

In FIG. 1, a 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 a starting end (left end) thereof, and a terminating end (from the starting end side). The microwave is transmitted toward the right end) side. The rectangular waveguide 1 is provided with an isolator 3 and a tuner 6 for bringing the plurality of wave adjusting members 4 into and out of each other so as to be matched with each other and to focus radio waves on the discharge tube 5.

The discharge tube 5 is composed of an inner tube and an outer tube,
It is arranged so as to be coaxial with the central axis of the cylindrical waveguide 7. Further, a Tesla coil 14 for generating a spark between the inner tube of the discharge tube 5 and the inner tube by the ignition device 13 is inserted. Further, an optical sensor 17 is provided to monitor the plasma generation state by detecting the luminous intensity.

A gas supply tube 16 is inserted tangentially to the outer tube of the discharge tube 5 so as to be filled with argon gas, an organic halogen compound to be decomposed, air.
Also, the water vapor is supplied to the discharge tube 5 via the gas supply tube 16. These argon gas, CFC gas, and air are supplied to the solenoid valves 19a, 19b, 1
By the opening and closing operation of 9c, the respective supply sources selectively send the heaters to the heater 18.

Argon gas is supplied to facilitate ignition prior to the generation of plasma, and is stored in the argon cylinder 21. This argon cylinder 21
A pressure regulator 22 and a pressure switch 23 are provided between the solenoid valve 19a and the solenoid valve 19a.

The air is supplied from the air compressor 24 in order to remove the water remaining in the system to improve the stability of ignition and to discharge the gas remaining in the system. , Nitrogen gas, argon gas, etc. are used. The steam is necessary, for example, in the case of decomposing CFC gas, and is generated by sending the water in the water storage tank 26 to the heater 18 by the plunger pump 25. The water storage tank 26 is provided with a level switch 27 that detects a change in water level.

A CFC gas, which is an example of an organic halogen compound to be decomposed, is liquid-stored in a CFC recovery tank 28, and the CFC recovery tank 28 and the solenoid valve 1 are used.
9b, the expansion device 31, the mist separator 3
2 and a pressure switch 33 are provided. The expansion device 31 is provided for the purpose of quantifying the flow, and is composed of, 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 a collision type or a centrifugal type is adopted. The heater 18 is intended not only to generate steam that reacts with CFC gas, but also to avoid the problem that steam is cooled to CFC gas and recondensed in the apparatus by preheating CFC gas and the like. The heating method such as electric type and steam type is adopted.

In the heater 18, two flow paths 3 arranged in parallel are provided.
4a, 34b are formed, and a freon gas, an argon gas, and air are introduced into one flow path 34a,
Water is introduced from the water storage tank 26 into the other flow path 34b to generate water vapor. The flow path 34b on the side of generating the steam is filled with a resistor 35 that gives resistance to the steam moving in the flow path 34b, so that the steam cannot flow smoothly in the flow path. Has become.

As the resistor 35, an inorganic or organic granular, fibrous, porous one or a molded product thereof is adopted. From the viewpoint of preventing deterioration at high temperatures, SiO ₂ , Al is used. ₂ O ₃ , TiO ₂ , MgO, ZrO ₂
Inorganic materials such as oxides represented by, and carbides, nitrides and the like are preferable. A thermocouple 36 is provided near the outlet of the heater 18.

However, the chlorofluorocarbon gas and the water vapor which 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. And
Due to the thermal plasma formed in the discharge tube 5, the reaction tube 15
Disassembled within.

The exhaust gas treatment tank 41 is provided for neutralizing and detoxifying the acidic gas (hydrogen fluoride and hydrogen chloride) produced when the CFC gas is decomposed, and is made of water and calcium hydroxide. It contains an alkaline suspension to which is added. For example, in the case where the decomposed CFC gas is CFC R12 for a refrigerant recovered from a waste refrigerator, the formula 1
The produced gas produced by the decomposition reaction shown in (1) is rendered harmless by the neutralization reaction shown in Equation (2). (Formula 1) CCl ₂ F ₂ + 2H ₂ O → 2HCl + 2HF + CO ₂ (Formula 2) 2HCl + Ca (OH) ₂ → CaCl ₂ + 2H ₂ O 2HF + Ca (OH) ₂ → CaF ₂ + 2H ₂ O

Since the neutralization products (calcium chloride and calcium fluoride) produced by the neutralization reaction of the formula 2 have a low solubility, some of them are dissolved in the alkaline solution, but most of them exist as a slurry. Further, the carbon dioxide produced by the decomposition reaction of the formula 1 and the acid gas reduced to a very small amount equal to or less than the emission reference value by the neutralization reaction of the formula 2 are exhaust duct 42 connected above the exhaust gas treatment tank 41. Is discharged from the system by the blower 43.

Inside the exhaust gas treatment tank 41, a blow pipe 45 connected to the reaction pipe 15 through an exchange joint is arranged so as to extend vertically with the open lower end portion thereof being immersed in an alkaline solution. ing.

At the axially intermediate portion of the reaction tube 15, a cooler 46 having a cold water pipe (not shown) is attached so as to surround the peripheral surface thereof. The cooler 46 cools the gas produced by the decomposition reaction of Equation 1, and the reaction tube 1
In order to prevent the re-condensation of the residual water vapor in 5, the cooling is controlled so that it does not cool below its dew point. For example, it is cooled to about 400 ° C.

The cooling water (warm water) of the cooler 46, which is warmed by cooling the reaction tube 15, is used as a heating source of the recovered CFC cylinder 28. That is, the heater 4 provided with hot water pipes (not shown) around the recovery flon cylinder 28.
7 is attached, and the cooling water used for cooling the reaction tube 15 flows through the hot water pipe, so that the recovered flon cylinder 28 is heated.

From the tip (lower end) of the blow pipe 45, the gas produced by the decomposition reaction of the formula 1 is discharged as bubbles in the alkaline liquid. The neutralization reaction in the alkaline liquid is promoted as the contact area between the bubbles and the alkaline liquid is large and the time it takes for the bubbles to reach the liquid surface is long. Therefore, the bubbles are finely divided in the exhaust gas treatment tank 41. A bubble dividing means 52 is provided which accelerates the neutralization reaction of Formula 2 by dividing.

The bubble dividing means 52 is fixed to a shaft portion 52b which is rotationally driven by a motor 52a, a disk-shaped blade holding portion 52c fixed to the tip of the shaft portion 52b, and an outer edge portion of the blade holding portion 52c. And six blades 52d that are formed. The bubble dividing means 52 is
The center of the blade holding portion 52c is arranged so as to be located above the tip of the reaction tube 15, and bubbles floating from the tip of the reaction tube 15 hit the blade 52d rotating at 300 rpm, for example, and have a diameter of about 3 mm to 5 mm. Finely divided into bubbles. In addition, the bubble dividing means 52 also plays a role of producing a suspension of water-insoluble calcium hydroxide and water by stirring the calcium hydroxide powder put into the exhaust gas treatment tank 41.

Further, the exhaust gas treatment tank 41 is provided with a cooler 53 for cooling the temperature inside the tank to a temperature not higher than the heat resistant temperature of the blow pipe 45 because the neutralization reaction of the equation 2 is an exothermic reaction. In this cooler 53, a part of the pipe connected to the heat radiating portion 53b cooled by the fan 53a is inserted through the exhaust gas treatment tank 41, and heat is generated by circulating a cooling medium such as water through this pipe. The heat dissipation part 53
It radiates heat in b. Here, the temperature in the tank is detected by the thermocouple 54. Further, the exhaust gas treatment tank 41 is provided with a pH sensor 55.

Since the slurry in the exhaust gas treatment tank 41 gradually increases with the lapse of operation time, after the operation is stopped, it is received by the solid-liquid separator 62 together with the alkali liquid, and is solid-liquid separated, and then as waste. It will be disposed of or used for other purposes. On the other hand, the separated alkaline liquid is
It is returned to the exhaust gas treatment tank 41 again and reused.
By the way, the fluctuation of the liquid level in the exhaust gas treatment tank is detected by the level switch 56.

For example, in the conventional apparatus for decomposing an organic halogen compound having the above-mentioned structure, as described above, (1) since the tip portion 45a is bent at about 30 ° from the horizontal plane, It is difficult for the accumulated matter to fall due to gravity (FIG. 2). (2) Since the cross-sectional area of the tip portion is constant, the gas ejection speed from the tip portion 45a is relatively slow at about 3 to 4 m / s. The slurry stored in the tank 41 instantaneously enters the tip portion 45a, and the sticky substance in the slurry adheres to the inner surface of the tip portion 45a. (3) When the operation is stopped, the tip portion 45a is also included. The problem that the clogging 45b frequently occurs at the tip 45a due to the reason that the slurry enters the blow-in pipe 45 and the sticky substance in the slurry adheres to the inner surface of the tip 45a. There was.

In the apparatus for decomposing an organohalogen compound according to the present invention, various means for solving the problems are proposed in order to overcome the problem of clogging of the tip portion of the blow-in tube.

In one solution of the present invention, as shown in FIG. 3, the tip portion 145a of the blow pipe 145 is tapered. Thereby, the gas flow velocity from the tip portion 145a is at least 20 m from the conventional 3 to 4 m / s.
/ S or more. For example, it increases to 40-60 m / s. As a result, it is possible to prevent a momentary intrusion phenomenon of the slurry in the exhaust gas treatment tank 41 and prevent clogging of the inner surface of the tip portion 145a.

In another solution of the present invention,
The tip portion 145a of the blow pipe 145 is subjected to non-adhesive processing (not shown) such as fluororesin processing. As a result, the sticky substance is unlikely to adhere to the inner surface of the tip portion 145a, and even if it adheres, it can be easily removed.

In yet another solution of the invention,
An air supply mechanism (not shown) supplies a purge gas such as air or an inert gas to the blow pipe 145 when the operation of the decomposition device for an organic halogen compound is stopped. As a result, the slurry does not enter the tip portion 145a when the operation is stopped and the slurry does not come into contact with the inner surface of the tip portion 145a, so that clogging of the inner surface of the tip portion can be prevented.

In another solution of the present invention, the pressure sensor 150 is installed upstream of the blow pipe 145. As a result, for example, when the pressure of 0.05 MPa or more is detected, the blow pipe maintenance signal is issued. That is, it is possible to constantly monitor whether or not the tip portion 145a is clogged.

In another solution of the present invention, the tip portion 145a of the blow pipe 145 is inclined at an angle of 60 ° or more from the horizontal direction. As a result, even if an adhering matter is formed, the adhering matter is likely to drop due to gravity, and the tip 1
It is possible to suppress clogging of 45a.

In the above description, various solving means for preventing clogging of the tip end portion 145a of the blow-in pipe 145 have been individually described, but these plural solving means can be used independently. ,
It can also be used in any combination. The most preferred embodiment is to carry out all the solutions simultaneously.

[0041]

The apparatus for decomposing organic halogen compounds according to the present invention has the following effects. According to the invention described in claim 1, since the tip portion of the blow-in pipe has a tapered shape, the gas flow velocity from the tip portion is, for example, 3 of the conventional case.
It increases from 4 m / s to 20 m / s or more, the instantaneous phenomenon of slurry intrusion can be prevented, and clogging of the inner surface of the tip can be prevented. According to the second or third aspect of the invention, since the tip portion of the blow-in pipe is subjected to non-adhesive processing such as fluororesin processing, the sticky substance is unlikely to adhere to the inner surface of the tip portion. Moreover, even if they are attached, they can be easily removed. According to the invention described in claim 4, the purge gas is supplied to the blow-in pipe by the air supply mechanism when the operation of the decomposition device of the organic halogen compound is stopped, so that the slurry may enter the tip portion when the operation is stopped. Since the slurry is not brought into contact with the inner surface of the tip portion, clogging of the inner surface of the tip portion can be prevented. According to the invention described in claim 5, since the pressure sensor is installed on the upstream side of the blow-in pipe, it is possible to constantly monitor the occurrence of clogging of the tip portion. According to the invention of claim 6, since the tip end portion of the blow-in pipe is inclined at an angle of 60 ° or more from the horizontal direction, even if an adhering matter is formed, it easily falls due to gravity, and the tip end portion is clogged. Can be suppressed.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of an organic halogen compound decomposing apparatus according to a conventional technique.

2 is an enlarged view showing a blow pipe in the disassembling apparatus of FIG. 1. FIG.

FIG. 3 is an enlarged view showing a blowing pipe in the decomposition apparatus for an organic halogen compound according to the present invention.

[Explanation of symbols]

15 reaction tubes 41 Exhaust gas treatment tank 145 blow pipe 145a tip 150 pressure sensor

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C07B 37/06 H05H 1/42 C07C 19/10 B01D 53/34 134E H05H 1/42 ZAB (72) Inventor Harunobu Mizuno 1 Takamichi, Iwazuka-cho, Nakamura-ku, Nagoya, Aichi Prefecture Mitsubishi Heavy Industries Nagoya Research Institute F-term (reference) 4D002 AA17 AA19 AA21 AA22 AA23 AB01 AC10 BA02 BA07 CA06 DA05 DA12 EA02 GA01 GA02 GB04 GB20 HA03 HA06 4D020 AA10 BA02 BA08 BB03 CB02 CC05 CC15 CC18 DA02 DA03 DB04 DB12 4G075 AA03 AA37 BA05 BB04 BD27 CA26 CA47 DA02 EA01 EB21 EC01 FB12 4H006 AA04 AA05 AC13 AC26

Claims (6)

[Claims] 1. An apparatus for decomposing organic halogen compounds, comprising an exhaust gas treatment tank for containing an alkali liquid, a blow pipe installed with its open tip immersed in the alkali liquid, and connected to the blow pipe. And a reaction tube which is supplied with an organohalogen compound to be decomposed and decomposes the organohalogen compound by electric discharge, wherein the tip end portion of the blow-in tube is tapered. A characteristic organic halogen compound decomposing device. 2. An apparatus for decomposing organic halogen compounds, which comprises an exhaust gas treatment tank containing an alkaline liquid, a blow pipe installed with its open tip immersed in the alkali liquid, and a connecting pipe to the blow pipe. And a reaction tube which is supplied with an organohalogen compound to be decomposed and decomposes the organohalogen compound by electric discharge, wherein the tip portion of the blow tube is subjected to non-adhesive processing. An apparatus for decomposing organic halogen compounds, which is characterized in that 3. The decomposition apparatus for an organic halogen compound according to claim 2, wherein the non-adhesive processing is a fluororesin processing. 4. An apparatus for decomposing organic halogen compounds, comprising an exhaust gas treatment tank containing an alkali liquid, a blow pipe installed with its open tip immersed in the alkali liquid, and connected to the blow pipe. And a reaction tube which is supplied with an organohalogen compound to be decomposed and decomposes the organohalogen compound by electric discharge, and supplies a purge gas to the blow tube when the decomposition apparatus is not operating. An apparatus for decomposing organic halogen compounds, which is provided with an air supply mechanism for 5. The decomposition apparatus for an organic halogen compound according to claim 1, wherein a pressure sensor is installed on the upstream side of the blow-in pipe. 6. The apparatus for decomposing an organic halogen compound according to claim 1, wherein the tip end portion of the blow-in pipe is inclined by 60 ° or more from the horizontal direction. Decomposing device for organic halogen compounds.