JPH07194730A - Decomposition method of halogenated compound and decomposition reactor therefor - Google Patents

Abstract

PURPOSE:To provide a decomposition method of a halogenated compd. capable of efficiently decomposing the halogenated compd. in a short period of time with an extremely high decomposition rate with simple equipment. CONSTITUTION:This decomposition method of the halogenated compd. has constitution to decompose the halogenated compd. by executing arc discharge under a condition of ordinary temp. to 200 deg.C in the halogenated compd. or a soln. mixture composed of a halogenated compd.-contg. soln. and a basic soln.

Description

Detailed Description of the Invention

[0001]

The present invention relates to halogenated compounds, especially P
The present invention relates to a method for decomposing a halogenated compound, which is also suitable for decomposing a polyhalogenated compound such as CB, and a decomposition reactor therefor.

[0002]

2. Description of the Related Art Conventionally, polyhalogenated biphenyl (hereinafter referred to as PCB) is excellent in heat resistance, chemical resistance, and electrical insulation, so that it is a heating medium for heat treatment, an additive of paint or ink, insulation of capacitors and transformers. It was widely used as an agent. However, since it was found that PCB is an environmental pollutant that is harmful to the human body and difficult to decompose in the natural world, detoxification treatment has been desired. However, due to its physical and chemical stability, general detoxification treatment is difficult, and various studies and developments have been made for detoxification. For example, JP-A-49-82570 and JP-B-56
39-290 and JP-A-2-241586 disclose a method of thermally decomposing PCB with or without mixing with an alkali metal, hydrogen gas or the like at a high temperature of 1200 ° C to 1500 ° C. Japanese Unexamined Patent Publication No. 50-84771 discloses a device for decomposing a PCB using a thermal decomposition furnace, and Japanese Patent Publication No. 2-5100 discloses a device for decomposing harmful materials such as a PCB using a thermal decomposition furnace and a DC arc. It is disclosed. Japanese Laid-Open Patent Publication No. 50-63005 and Japanese Patent Publication No. 61-597.
Japanese Patent Publication No. 79 discloses a method of irradiating a mixture of PCB and a basic substance with ultraviolet rays to perform photolysis. Japanese Patent Application Laid-Open No. 1-205510 discloses a method in which KOH pellets and polyethylene glycol are added to PCB and chemically decomposed in an N ₂ gas atmosphere.

[0003]

However, the above-mentioned conventional thermal decomposition method requires extremely high temperature, requires a large amount of energy, and is much more toxic than PCB due to the lowering of the incineration temperature, and thus polychlorinated dibenzofuran (PCD).
It has a problem that the generation of F) and dioxin is concerned. In addition, the photodecomposition method using ultraviolet rays has a problem that the decomposition rate is low and the efficiency is low only by using ultraviolet rays alone or by using ultraviolet rays and ozone. Furthermore, the chemical decomposition method uses various chemicals, which increases the cost and
There is a problem that the handling of chemicals is inferior in workability and difficult to handle. Further, the method using a DC arc is to decompose the vapor of a halogenated compound generated when the PCB is decomposed in a pyrolysis furnace, and the electrodes are required to have heat resistance in order to generate a DC arc in the pyrolysis furnace. In addition, there is a problem that the device is large-scale and difficult to use.

The present invention solves the above conventional problems and provides a method for decomposing a halogenated compound, which is capable of efficiently decomposing the halogenated compound with a very high decomposition rate in a short time with a simple facility, It is another object of the present invention to provide a halogenated compound decomposing apparatus that is energy-saving and has a simple structure and can decompose even a polyhalogenated compound efficiently with an extremely high decomposition rate.

[0005]

To achieve this object, the present invention has the following constitution. The method for decomposing a halogenated compound according to claim 1, wherein a halogenated compound is mixed with a halogenated compound or a solution containing the halogenated compound and a basic solution, and arc discharge is performed under normal temperature to 200 ° C. It has a constitution for decomposing a compound. The method for decomposing a halogenated compound according to a second aspect has a configuration according to the first aspect, in which ozone is added to the halogenated compound or the halogenated compound-containing solution. The halogenated compound decomposing method according to a third aspect has the configuration according to the second aspect, wherein the ozone is ozone water or ozone gas. The method for decomposing a halogenated compound according to claim 4 is the method for decomposing a halogenated compound according to any one of claims 1 to 3, wherein the arc discharge fills a space between the container-shaped electrode and the rod-shaped electrode. The structure is performed in the gap. A method for decomposing a halogenated compound according to claim 5 is the method according to any one of claims 1 to 3, wherein the arc discharge is a rotating electrode formed in a drum shape or a rod shape.
It has a configuration that is performed between fixed rod-shaped electrodes.
The method for decomposing a halogenated compound according to claim 6, wherein a step of decomposing a halogenated compound or a mixed solution of a halogenated compound-containing solution, a basic solution, and optionally ozone, by arc discharge, A step of separating a decomposition reaction solution containing undecomposed matter subjected to arc discharge into an oil and a slurry solution; a step of cooling the decomposition reaction solution or the oil; and the oil and a halogenated compound or a halogenated compound. A step of adding a basic solution and, if necessary, ozone to a mixture with the containing solution and circulating the mixture to the decomposition treatment step by arc discharge. A decomposition method of a halogenated compound according to a seventh aspect is the method according to any one of the first to sixth aspects, wherein the mixed solution is in a dispersed state or an emulsified state.
9. A decomposition reactor for a halogenated compound according to claim 8, wherein a container electrode having a solution to be decomposed made of a halogenated compound and the like and an outlet for the decomposition treatment liquid and having a cooling jacket, and a container electrode inside the container electrode One or a plurality of fixed electrodes mounted on the container, and a conductor filled inside the container electrode,
It has a configuration including. The decomposition reactor for a halogenated compound according to claim 9, wherein the reaction container has a cooling jacket and is provided with an inflow part for a solution to be decomposed composed of a halogenated compound or the like and an outflow part for a decomposition treatment liquid, and is mounted on the reaction container. A hollow or rod-shaped rotating electrode such as a drum, a rotating machine for rotating the rotating electrode, and a tip portion spaced apart from the rotating electrode by 0.1 to 5 mm, preferably 0.5 to 3 mm. And a rod-shaped electrode attached to the reactor so as to be movable back and forth.

Here, the halogenated compounds include alkyl halides, aryl halides, acyl halides and other chlorinated compounds, bromides, fluorides and mixtures thereof, pesticides, PCBs, dioxins, etc., and halogen with a low molecular weight. The liquid having a low conversion rate to a solid state having a halogenation rate of 55% or more such as a polyhalide may be used, but it is preferable to dissolve the solid or the solid having a high viscosity in a solvent. As the solvent, lubricating oil such as transformer oil, condenser oil, cable oil or the like having a high boiling point and higher hydrocarbon compounds are used. Ozone gas or ozone water is used as ozone. In the case of ozone gas, a high concentration one is preferable because it shows a high decomposition rate, but a low concentration one can be used by mixing in multiple stages. The concentration of ozone gas is 10
0ppm-50000ppm, preferably 500ppm
A substance having a concentration of 10000 ppm is used. When the concentration is low, the decomposition rate cannot be increased, and when the concentration is high, undecomposed ozone gas is likely to be generated, and a detoxification treatment step or the like is required and the apparatus becomes large in size, which is not preferable. High concentration ozone water is also preferable, but ozone gas is more preferably used when the reaction system is heated. As the basic solution, KOH, NaOH or the like as a basic substance, or a mixture thereof, and an aqueous solution obtained by adding another halogen scavenger to these are preferably used for economic reasons. These are used in the form of an aqueous solution or methanol. You may use what was melt | dissolved in alcohols, such as. The concentration of the base in the basic solution depends on the concentration of halogen, but is 5 to 90 wt%, preferably 10 to 50 wt%. The higher the base concentration, the higher the decomposition rate. When it is less than 10 wt%, it tends to take a long time to decompose, which is not preferable. A halogen scavenger may be used. The solution of the halogenated compound, the basic solution and ozone are preferably subjected to arc discharge treatment in a dispersed state or an emulsified state. The rate of decomposition can be increased by dispersing or emulsifying. Dispersion and emulsification are carried out by mechanical mixing or mixing with an ultrasonic processor or a homogenizer. Incidentally, a dispersant or an emulsifier may be added to the system. This is because the emulsified state can be maintained for a long time. The decomposition reactor may be of a substantially cylindrical shape or a substantially flat shape, but the bottom is preferably formed in a funnel shape. This is to prevent the decomposition reactor from being clogged with the powdered material of the electrodes. A carbon electrode, a tungsten electrode, a platinum electrode, or the like is used as the rod-shaped electrode. As the conductor, activated carbon, coke, crushed product of fired carbon, or other substances having arc discharge properties are used. However, those having a weak positive column are not preferable because the decomposition rate is low. The average particle size of the conductor is 1 to 50 mm, preferably 2
Those having a thickness of -30 mm, more preferably 5-10 mm are preferably used. As the average particle size becomes smaller than 5 mm, the packing density of the conductors becomes higher, so the gap between the conductors becomes too narrow and the positive column tends to become shorter. All of them are not preferable because the number of times tends to decrease. In addition, it is recognized that the number of discharge points tends to increase when the surface of the conductor is roughened rather than smoothed. The rotating electrode may be any as long as it can perform arc discharge, but one made of a metal such as copper or carbon is preferably used. Rotation of the rotating electrode is preferably changed by a servomotor or the like, which can be changed according to the arc current. Since the rotating electrode rotates, the plurality of rod-shaped electrodes can be installed so as to face the surface of the rotating electrode, and the processing performance can be increased as the number of the rod-shaped electrodes installed increases. The arc discharge can be performed intermittently by a pulse signal or the like instead of continuously. In the case of intermittent operation, the discharge cycle and discharge time can be set arbitrarily according to the capacity of the decomposition reactor and the type of electrode, and the temperature control of the decomposition reactor can be facilitated, and the operability and safety of the decomposition device can be improved. Can be improved.

[0007]

With this configuration, it is possible to locally obtain an ultrahigh temperature by performing arc discharge in a solution.
It is possible to easily dehalogenate a halogenated compound in an ultrahigh temperature range. Ozoniso can be decomposed with a basic solution, and thus can be safely decomposed.
The halogen ion dehalogenated by the basic solution can be easily captured, and the reaction rate can be accelerated. The solvent and water become a heat absorber and can absorb the high heat of the positive column of the arc discharge and play a role of a heat insulator. Since the space between the container-shaped electrode and the rod-shaped electrode is filled with the lump or granular conductor, arc discharge can be performed between the gaps, and the C—Cl bond of the halogenated compound existing in the gap can be generated. Can be divided. Further, since ozone is present, ozone acts on the excited C—Cl bond to form ozoniso, so that the decomposition rate can be increased. Bulk or granular conductors were generated by decomposition because the contact points were random and at the same time there was an insulating agent between the contacts, so the conductors constantly fluctuated due to the impact at the same time as the arc was generated. It is possible to prevent contamination by carbides and powders of conductors, and to obtain stable arc discharge. Since the number of contact points decreases and the gap increases in proportion to the size of the conductor, the positive column can be made larger, and the local temperature can be increased accordingly. Further, the decomposition reaction conditions can be easily changed by changing the size of the conductor. If both facing electrodes are rod-shaped carbon electrodes, the arc is difficult to fly, and carbide is easily generated and adheres between the electrodes, but since the electrodes rotate by using a rotating electrode, the formation of carbide between the electrodes And adhesion can be prevented, and the arc can easily fly. In addition, when the drum electrode and the rod-shaped carbon electrode are used, carbide does not adhere and stable operation can be performed for a long time.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the drawings. (Example 1) FIG. 1 is an external perspective view of a decomposition reactor for a halogenated compound of Example 1, and FIG. 2 is a longitudinal sectional view of an essential part thereof. Reference numeral 1 is a decomposition reactor of the first embodiment, 2 is a decomposition tank of the decomposition reactor 1, 3 is a jacket portion through which cooling water for adjusting the temperature of the decomposition tank 2 flows, 4 is a tray made of a wire mesh, a perforated plate, or the like, 4a Is a tray support for supporting the tray 4, 5 is an electrode terminal, 5'is a ground terminal, and 6 is connected to the conductive portion of the electrode terminal 5 and is suspended in the central portion of the decomposition tank 2 in the diameter direction. A carbon electrode, 7 is a conductor made of crushed material of activated carbon having an average particle size of 5 to 10 mm filled up to the upper part of the carbon electrode 6 or calcined carbon, 8 is an inflow portion of a material to be decomposed such as PCB, and 9 is decomposed. And 10 are gas outlets of air mixed with ozone gas and reaction product gases such as CO and CO ₂ , 11 is a cooling water inflow portion of cooling water that flows into the jacket portion 3, 12 Is a cooling water outflow portion of the cooling water supplied to the jacket portion 3. Although the fixed electrode is suspended in the present embodiment, one or a plurality of fixed electrodes may be provided on the side wall of the decomposition tank. The decomposition method of this example using the decomposition reactor configured as described above will be described below with reference to the decomposition process chart of the halogenated compound. FIG. 3 is a decomposition process diagram of the halogenated compound using the decomposition reactor of the halogenated compound of the first embodiment. 1
a, 1b, and 1c are first, second, and third decomposition reactors for the halogenated compound of the first embodiment, which are connected in series in three groups, 13
Is a raw material storage tank for storing a solution of a halogenated compound and separating the decomposition reaction liquid from the third decomposition reactor 1c by gas-liquid separation, and then circulating an oily substance containing undecomposed material to the first decomposition reactor 1a, 13a Is a constant quantity feeder for flowing a predetermined amount of the halogenated compound-containing solution from the raw material storage tank 13, 14 is an air compressor,
Reference numeral 15 is an ozone producing machine for producing ozone from the air of the air compressor 14, 16 is an ozone rectifier for outflowing a predetermined amount of ozone, 17 is a basic solution storage tank such as NaOH or KOH solution adjusted to a predetermined concentration, 18 Is a constant quantity feeder for supplying a basic solution, 19 is a mixer for mixing halogenated compounds such as PCB, ozone and a basic solution into an emulsified state, and 20 is a third
A supply pump for supplying the decomposition reaction liquid of the decomposition reactor 1c to the liquid cyclone, 21 is a liquid cyclone for separating the decomposition reaction liquid into a slurry solution in which NaCl or the like is dissolved, and an oily material, 2
Reference numeral 2 is an oil storage portion, 23 is a slurry solution storage portion, 24 is a cooler for cooling the decomposition reaction liquid with cooling water, and 25 is undecomposed ozone gas, air, CO, CO mixed in the decomposition reaction liquid.
A condenser for separating reaction product gases such as _{2 and the} like, a gas releasing portion 26 for detoxifying toxic gas such as ozone gas and then releasing it to the atmosphere, and 27 for air and CO, CO from each decomposition reactor 1a, 1b, 1c. A gas pipe for introducing a reaction product gas such as ₂ into the gas discharge part 26, and 28 is an outflow pipe for a decomposition reaction liquid containing undecomposed substances of each decomposition reactor 1a, 1b, 1c and a slurry solution containing carbon and the like. .

(Experimental Example 1) Using the decomposition reactor of Example 1, a decomposition experiment of PCB was carried out by a decomposition method using the decomposition apparatus shown in FIG. <Preparation of raw materials> a. As a sample, 1,2,4-trichlorobenzene-containing trans oil 10.7 wt% and No. 2 trans oil 65.5 wt%
And 17.3 liter (16.7 kg) of a mixed solution of 16.7 wt% of water and 7.1 wt% of NaOH was prepared. The PCB
Was adjusted to 10 4 g / l. A commercially available PCB was used. b. As a conductor, activated carbon (Quintol-WA) 4 ~
An 8-mesh one was used by filling each decomposition tank. c. As the decomposition reaction tank, a cylindrical decomposition reactor shown in FIG. 2 having three groups arranged in series as shown in FIG. 3 was used. <Arc discharge conditions> The following conditions were set. a. Arc discharge voltage: 50 V b. Arc discharge current: 200-220A c. Arc discharge cycle (per unit): 36 sec d. Arc discharge time (per unit): 10 sec e. A carbon electrode having a diameter of 10 mm and a length of 300 mm was used as the arc electrode. <Test conditions> a. Circulation flow rate of sample in decomposition device 450 liter / hr
I adjusted it to. b. Ozone was supplied by supplying ozone-containing air having a concentration of 3000 ppm at 540 l / hr. During the test, ozone gas was constantly supplied by opening the valve V ₂ in FIG. c. It was performed so that the average flow velocity of the liquid in each decomposition tank was 32.4 m / hr. d. Since the basic solution was mixed in the sample in advance, the valve V _{1 in} FIG. 3 was closed. e. The circulation time of the sample in the decomposer was set to 6 hours. f. The temperature inside each decomposition tank was set to 100 ° C to 120 ° C. g. The mixer used was a mechanical mixer in which two rotating bodies, in which wire-brush-like ones were densely packed, were rotated in opposite directions to form an emulsion. h. The sample and ozone were mixed in an emulsified state by the mixer 19 to generate an emulsion, which was supplied to the decomposition reactor 1a and circulated as a closed loop in FIG. <Test Results> The concentration of PCB in the oily substance was measured by gas chromatography. The results are shown in (Table 1). Exhaust carbon and tar-like substances were contained in the slurry solution, so the liquid from which the water was separated was measured by the AgNO ₃ method, and a Cl ^- concentration that was approximately stoichiometrically matched with the decomposed PCB was measured. It was No PCB was observed when the tar content was measured by the sublimation gas chromatography method.

[Table 1]

(Experimental Example 2) The experiment was conducted in the same manner as in Experimental Example 1 except that a crushed product of fired carbon was used as the conductor instead of the activated carbon. The results are shown in (Table 1).

(Experimental Example 3) A PCB decomposition experiment was conducted under the same conditions as in Experimental Example 1 except that ozone was not mixed. The results are shown in (Table 1).

As is clear from this (Table 1), according to this embodiment, a. It was found that high-concentration and hardly decomposable PCB can be decomposed by 97% or more. When the experiment was further continued for 5 hours in Experimental Example 3, the decomposition was 99% or more. From this, it was found that if the decomposition time is further lengthened, the decomposition can be carried out to about 100%. b. It was found that the lump-shaped or particle-shaped conductors filled in the space between the container-shaped electrode and the rod-shaped electrode have random gaps, and a strong positive column can be obtained in each gap. It was also found that the rougher the surface of the conductor, the more suitable the gap for arc discharge can be obtained. Furthermore, it was found that by increasing the voltage, a strong positive column can be obtained even if the particle size is large. c. It was found that the position of the conductor fluctuates due to the shock generated by the arc discharge and constantly fluctuates. As a result, it was found that the contact surface was constantly renewed, and there was no contamination of reaction products or carbides by powdered electrodes, and stable arc discharge was performed. d. From this, it was also found that the decomposition reactor can be easily scaled up, a large voltage and a large current can be applied, and a large capacity decomposition reactor can be constructed with a simple device. e. It was found that there is no need to adjust the gap between the electrodes and the operation is extremely simple and labor can be saved. f. It was found that the number of contact points changes depending on the size of the conductor, the size of the positive column can be changed, and the local temperature can be changed under the same volume and the same voltage in the decomposition reactor. Also, in proportion to the size of the conductor,
It was also found that the contact points could be reduced, the positive column could be increased and the local temperature could be increased. Therefore, it was found that the decomposition reaction condition can be easily selected as the optimum condition by changing the size of the conductor. g. Various metals as conductors, baked carbon, coke,
Experiments were carried out using activated carbon and the like, but almost the same results were obtained. It was also found that the same result can be obtained even if the NaOH solution is not mixed with the sample and is put in the basic solution storage tank. However, it was found that it was necessary to supply so as to maintain the emulsified state. In addition, in the present embodiment, the case where three decomposition reactors are installed in series has been described, but ozone water or ozone gas is mixed in a mixed solution of a halogenated compound and a predetermined amount of basic solution in one decomposition reactor. Then, the emulsified product can be charged and decomposed in a batch system.

(Embodiment 2) FIG. 4 is a plan view of an essential part of a decomposition reactor for polyhalogenated compounds according to a second embodiment of the present invention, and FIG. 5 is a longitudinal sectional view of an essential part of the decomposition reactor. , Fig. 6
FIG. 4 is a cross-sectional view of a main part of an electrode insertion part of a decomposition reactor. Reference numeral 31 is a decomposition reactor for the polyhalogenated compound in the second embodiment of the present invention, 32 is a decomposition tank of the decomposition reactor 31, 33 is an outer periphery of the decomposition tank 32, and the center of the decomposition tank 32 is point-symmetrical at a symmetrical position. Carbon electrodes made of carbon or the like, which are inserted in the same or different manner so as to be movable back and forth, 34 is an electrode insertion portion having a sealing mechanism or an insulating mechanism inside, and 35 is a pressure-resistant glass. 5, a reference numeral 36 is a rotating machine including a servomotor for rotating a drum electrode made of copper or the like, and 37 is a detecting device arranging portion such as a pressure gauge, and in FIG.
Is a pressure gauge installed in the detection device installation section 37, 39 is a jacket section for cooling the decomposition tank 32 with cooling water, 40 is a cooling water inflow section, 41 is a cooling water outflow section, and 42 is a cover such as a halogenated compound. Decomposition liquid inflow portion, 43 is decomposition reaction liquid outflow portion, 4
Reference numeral 4 denotes a drum electrode made of copper or the like suspended from the rotating portion of the rotating machine 36. In FIG. 6, reference numeral 45 denotes a ceramic electrode support portion 45 in which a rod-shaped carbon electrode 33 made of a carbon electrode or the like is slidably inserted and fitted in an electrode insertion portion 34 in a close contact state, and 46 indicates a rod-shaped electrode 33. And packing 47 for preventing the decomposition reaction liquid from leaking from the gap between the electrode supporting portion 45 and 47, a flange 4 made of an insulating material such as ceramics, 4
Reference numerals 8 and 49 are bolts and nuts for fixing the flange 47 to the electrode insertion portion 34. The decomposition method of the halogenated compound of this example using the decomposition reactor configured as described above will be described below with reference to the decomposition step diagrams. FIG. 7 is a decomposition process diagram of a polyhalogenated compound using the decomposition reactor of the second embodiment of the present invention, and FIG. 8 is a side view of a main part of an interelectrode gap adjusting unit that moves the electrodes of the decomposition reactor back and forth. Is. The difference from the decomposition process diagram of the first embodiment of FIG. 3 is that the decomposition reactor 31 of the second embodiment is installed in place of the decomposition reactors 1a, 1b, 1c of the first embodiment, The same devices and the like as those in the disassembling process of the first embodiment are designated by the same reference numerals as those in FIG. 3, and the description thereof will be omitted. 50 is a carbon electrode 3
3 and slide the carbon electrode 33 back and forth to engage the carbon electrode 3
3 is an inter-electrode gap adjusting unit including a servo motor and the like for adjusting the gap between the rotating drum electrode 44 and the rotating drum electrode 44. In FIG. 7, reference numeral 51 is an electrode holding portion for axially attaching the carbon electrode 33 and supplying electric power, 52 is a power source for supplying electric power to the carbon electrode 33, and 53 is a drive portion including a geared motor for moving the carbon electrode 33 back and forth. , 54 is a screw shaft connected to the rotating part of the drive part 53, and 55 is a shaft attachment part that is integrally connected to the electrode holding part 51 via an insulating part 56 and is axially attached to the screw shaft 54. .

(Experimental Example 4) Using the cracking reactor shown in Example 2, a cracking experiment of trans oil containing PCB was carried out using the cracking apparatus for halogenated compounds shown in FIG. <Preparation of sample> a. Test sample: Waste transformer oil containing PC b. PCB concentration: 6.48 mg / liter c. Input amount of transformer oil: 20 liters d. Flow rate of transformer oil: 300 liters / hr <Arc discharge condition> -Liquid flow rate in reactor: 0.3 cm / sec-Gap between arc discharge electrodes: 2-3 mm-Arc discharge voltage: 50 V-Arc discharge current: 100- 150 A ・ Arc discharge cycle: 10 sec ・ Arc discharge time: 3 sec ・ Number of carbon electrodes: 4 (arranged at symmetrical positions) <Test conditions> a. KOH aqueous solution concentration: 10 wt% b. KOH flow rate: 0.5 liter / hr c. Ozone flow rate: 540 l / hr d. Ozone concentration: 3000 ppm e. Temperature in arc reactor: adjusted to 90 ° C f. Circulation time: 6 hours (calculated circulation number: 8.3 times /
hr, 50 times in total) g. Mixer: The same mixer as in Experimental Example 1 was used and was supplied in an emulsified state. <Test Results> The concentration of PCB in the oily matter was measured by gas chromatography. The results are shown in (Table 2). When the aqueous solution in the slurry solution was measured by the AgNO ₃ method, a Cl ⁻ concentration which was approximately stoichiometrically matched with the decomposed PCB was measured. When the tar content was measured by the sublimation gas chromatograph method, PCB was not recognized.

Experimental Example 5 A decomposition experiment was conducted under the same conditions as in Experimental Example 1 except that the number of carbon electrodes was two. The results are shown in (Table 2).

[Table 2]

(Comparative Example 1) Instead of the drum electrode 44,
A decomposition experiment was conducted under the same conditions as in Experimental Example 3 except that only the carbon electrode 33 was placed symmetrically with respect to the center line of the decomposition reactor 31 and the distance between the electrodes at the tip of the carbon electrode 33 was 2 mm. During the arc discharge, because the space between the electrodes is covered with transformer oil containing PCB etc., the arc is blown or not blown, and stable arc discharge cannot be obtained. Also, the generated carbide adheres to the surface of the electrode. , I found that I couldn't drive for a long time. As described above, according to this embodiment, a. It was found that the PCB can be decomposed by 99.9% or more. b. It was found that when both facing electrodes were rod-shaped carbon electrodes, the arc was difficult to fly, and carbides were easily formed between the electrodes and adhered. In the case of this embodiment of the rotary electrode system, the arc moves easily because the electrode moves, and since the copper drum electrode and the rod-shaped carbon electrode are used, it is found that the carbide does not adhere and the stable operation can be performed for a long time. It was c. It has been found that the arc discharge can also be performed intermittently with a pulse signal. As a result, it was found that the discharge cycle and discharge time can be set arbitrarily. d. It was also found that if the gap between the electrodes is adjusted by a servo mechanism to obtain the optimum arc current, the decomposition time can be further shortened with a high decomposition rate. e. It was found that any number of fixed rod electrodes can be set facing the rotating drum electrode, and the greater the number, the greater the processing capacity. However, it was found that brine or the like must be taken into consideration as cooling water because the reaction liquid becomes hot.

[0017]

As described above, the method for decomposing a halogenated compound of the present invention has a simple structure in which arc discharge is carried out in an emulsion solution containing a halogenated compound, a basic solution and, if necessary, ozone. It is possible to realize a method for decomposing a halogenated compound having the excellent effect of. a. A halogenated compound such as PCB can be decomposed in an extremely short time and at an extremely high decomposition rate. b. Since the halogenated compound can be decomposed not only in the batch system but also in the continuous system, high processing capacity can be exhibited. c. Since the equipment is simple, labor can be saved, and the energy consumption is much lower than before, so the running cost can be significantly reduced. d. Since the equipment is simple, it can be made compact and compact, so it can be loaded on a transport vehicle such as a tractor and can decompose halogenated compounds without taking up any space. Next, the halogenated compound decomposition reactor of the present invention has a simple structure in which a fixed electrode and a lumped or granular electric conductor, or a fixed electrode and a rotating electrode are combined, and has the following excellent effects such as PCB. It is possible to realize a decomposition reactor for halogenated compounds. a. Since the lump-shaped or granular conductor can move freely by the impact of arc discharge, the discharge site can be constantly renewed, a strong positive column can be continuously obtained, and a high decomposition rate can be obtained. b. Since it is a rotary type, reaction products do not adhere between the electrodes, so that a high decomposition rate and the same decomposition rate can be maintained.
c. In the case of the rotary type, the interelectrode gap adjusting unit can adjust the interelectrode gap to a gap that meets the decomposition conditions, so that the decomposition time can be calculated and the disassembly device can be easily designed. d. Since the shape and the number of fixed electrodes or rotating electrodes, or the shape of the conductor can be freely selected, the disassembling apparatus can be made larger or smaller, and the design flexibility is excellent. e. Since the device with a high decomposition rate can be downsized, the entire disassembling device can be made compact and can be loaded on a transport vehicle such as a tractor, and can also be a movable disassembling device.
It is possible to disassemble by directly moving the disassembling device for each PCB storage location. f. Since the decomposition reactor has a simple structure, it is low in cost and excellent in mass productivity.

[Brief description of drawings]

FIG. 1 is an external perspective view of a decomposition reactor for halogenated compounds according to a first embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view of a main part of a halogenated compound decomposition reactor according to the first embodiment of the present invention.

FIG. 3 is a decomposition process diagram of a halogenated compound using the decomposition reactor for a halogenated compound according to the first embodiment of the present invention.

FIG. 4 is a plan view of an essential part of a decomposition reactor for polyhalogenated compounds according to a second embodiment of the present invention.

FIG. 5 is a vertical cross-sectional view of a main part of a decomposition reactor for polyhalogenated compounds according to a second embodiment of the present invention.

FIG. 6 is a cross-sectional view of an essential part of an electrode insertion portion of the decomposition reactor for polyhalogenated compounds according to the second embodiment of the present invention.

FIG. 7 is a decomposition process diagram of a polyhalogenated compound using the decomposition reactor of the second embodiment of the present invention.

FIG. 8 is a side view of an essential part of an interelectrode gap adjusting section that moves the electrodes of the decomposition reactor of the second embodiment of the present invention back and forth.

[Explanation of symbols]

 1 Decomposition reactor of 1st Example 1a 1st decomposition reactor 1b 2nd decomposition reactor 1c 3rd decomposition reactor 2 decomposition tank 3 jacket part 4 tray 4a tray support 5 electrode terminal 5'ground terminal 6 carbon Electrode 7 Conductor 8 Inflow part 9 Outflow part 10 Gas outlet 11 Cooling water inflow part 12 Cooling water outflow part 13 Raw material storage tank 13a Fixed amount feeder 14 Air compressor 15 Ozone maker 16 Ozone rectifier 17 Basic solution storage tank 18 Quantitative feeder 19 Mixer 20 Feed pump 21 Hydrocyclone 22 Oily substance reservoir 23 Slurry solution reservoir 24 Cooler 25 Condenser 26 Gas release 27 Gas pipe 28 Outflow pipe 31 Decomposition reactor 32 of the second embodiment Decomposition tank 33 Carbon Electrode 34 Electrode Insertion Part 35 Viewing Window 36 Rotating Machine 37 Detecting Device Arrangement Section 38 Pressure Gauge 39 Jacket Section 40 Cooling Water Input part 41 Cooling water outflow part 42 Inflow part of liquid to be decomposed 43 Outflow part 44 Drum electrode 45 Electrode support part 46 Packing 47 Flange 48 Bolt 49 Nut 50 Electrode gap adjusting part 51 Electrode holding part 52 Power supply 53 Drive part 54 Screw shaft 55 Shaft mounting part 56 Insulation part

Claims (9)

[Claims] 1. A halogenated compound or a solution containing a halogenated compound and a basic solution are mixed in a mixed solution to decompose the halogenated compound by performing arc discharge at room temperature to 200 ° C. Method for decomposing halogenated compound. 2. The method for decomposing a halogenated compound according to claim 1, wherein ozone is added to the halogenated compound or a solution containing the halogenated compound. 3. The method for decomposing a halogenated compound according to claim 2, wherein the ozone is ozone water or ozone gas. 4. The arc discharge is generated in a gap portion of a lump-shaped or granular electric conductor filled between a container-shaped electrode and a rod-shaped electrode.
The method for decomposing a halogenated compound according to 1. 5. The arc discharge is performed between a rotating electrode formed in a drum shape or a rod shape and a fixed rod electrode, according to any one of claims 1 to 3. Method for decomposing halogenated compound. 6. A step of decomposing a mixed solution of a halogenated compound or a solution containing a halogenated compound, a basic solution and ozone optionally added, by arc discharge,
A step of separating the decomposition reaction solution containing the undecomposed material subjected to the arc discharge into an oil and a slurry solution; a step of cooling the decomposition reaction solution or the oil; and the oil and a halogenated compound or a halogenated compound. A method for decomposing a halogenated compound, comprising the step of adding a basic solution and, if necessary, ozone to a mixed solution with a compound-containing solution and circulating the mixture in the decomposition treatment step by arc discharge. 7. The method for decomposing a halogenated compound according to any one of claims 1 to 6, wherein the mixed solution is in a dispersed state or an emulsified state. 8. A container electrode having a cooling solution jacket having an inflow part of a solution to be decomposed composed of a halogenated compound and the like and an outflow part of a decomposition treatment solution, and one or a plurality of fixed electrodes mounted in the container of the container electrode. And a conductor filled inside the container electrode, wherein the halogenated compound decomposition reactor is provided. 9. A reaction vessel having a cooling jacket, which comprises an inflow part for a solution to be decomposed composed of a halogenated compound and the like, and an outflow part for a decomposition treatment solution, and a hollow or rod-like shape such as a drum attached to the reaction container. A rotating electrode, a rotating machine that rotates the rotating electrode, and a tip portion of the rotating electrode is 0.1 to 5 m.
A decomposition reactor for halogenated compounds, comprising a rod-shaped electrode mounted in the reaction vessel so as to be movable back and forth with a gap of m, preferably 0.5 to 3 mm.