JP2013202314A - Method and apparatus for decomposing organic halogen compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for decomposing an organic halogen compound and a decomposing apparatus, capable of decomposing an organic halogen compound remaining in a container of a large transformer in which a large amount of organic halogen compound contained in one batch of treatment liquid should be decomposed without causing fixation of a catalyst.SOLUTION: A method for decomposing an organic halogen compound includes: adding a hydrogen donor and an alkali compound to an organic halogen compound to prepare a mixed liquid; taking out all or some of the mixed liquid; allowing the taken mixed liquid to circulate in a catalyst-filled device; and irradiating the mixed liquid circulating in the catalyst-filled device with a microwave to decompose the organic halogen compound. In this method, the catalyst-filled device is formed by stacking a filling member layer on the top and an organic halogen compound decomposition catalyst layer on the bottom. The mixed liquid is introduced from the upper part of the catalyst layer on the top and discharged through the filling member layer on the bottom. A decomposing device is used for the method.

Description

  The present invention relates to an organic halogen compound decomposition treatment method and a decomposition treatment apparatus for decomposing an organic halogen compound to render the organic halogen compound harmless, and more specifically, in a container such as a pole transformer or a large transformer. The present invention relates to an organic halogen compound decomposition treatment method and a decomposition treatment apparatus for decomposing and detoxifying residual polychlorinated biphenyl (PCB).

  Among various organic halogen compounds, polychlorinated biphenyl (PCB) is extremely harmful to living organisms including the human body. Therefore, it was designated as a specific chemical substance in 1973 and its production, import and use are prohibited. However, tens of thousands of tons of PCB are left untreated without finding an appropriate disposal method. Since PCB is a by-product of highly toxic dioxins by high-temperature decomposition, it is difficult to safely decompose PCB, and various safe and efficient decomposition methods for PCB have been studied for many years.

  As a method for treating organic halogen compounds in containers such as pole transformers, a method of treating the organic halogen compounds together with the container, a method of separately treating the containers and the organic halogen compounds after extracting the organic halogen compounds from the container, and There is.

  As the former, for example, a pole transformer is housed in an autoclave containing water and an oxidant while containing oil containing PCB, and the autoclave is heated to oxidize PCB by bringing water into a supercritical state. There is a method of detoxifying the entire pole transformer containing the oil containing PCB by decomposing, but this method requires a large-scale device.

  As the latter, for example, after removing the insulating oil from the pole transformer, the pole transformer is washed with a solvent to make it harmless, while the drained oil is heated by adding alkali metal tertiary butoxide, etc. There is a method of detoxifying oil by stirring and decomposing PCB. However, since this system is a batch process, the equipment becomes very large for large-scale processing, and the catalyst is separated from the oil after the PCB decomposition process because the powdered catalyst is put into the oil as it is. However, when a fixed bed type catalyst is used instead of the powder catalyst, there are problems such as the reaction does not proceed satisfactorily because the contact opportunity with the PCB is reduced.

  Furthermore, since assessment is required for the construction of PCB processing equipment, PCB detoxification can be performed on-site such as transformer storage, and PCBs can be safely processed in large quantities at low cost. There is a detoxification method using waves. In this treatment method, PCB, hydrogen donor (isopropyl alcohol), and alkali compound are mixed in a container, and then the liquid is extracted from the container and distributed to an apparatus filled with a catalyst such as a metal-supported carbon compound while being irradiated with microwaves. Then, it is a treatment method in which the PCB is decomposed again by circulation in the container (see, for example, Patent Documents 1 to 5).

  However, in the above treatment method, if a large amount of alkali is introduced into one batch of liquid to decompose a large amount of PCB, a large amount of KCl, which is a by-product of the PCB decomposition reaction, is generated, and the by-product becomes a catalyst. Accumulation on the catalyst in the lower layer portion in the filling device causes the catalyst to be fixed, which makes it impossible to circulate the liquid, thus causing a problem of inhibiting the PCB decomposition process.

JP 2007-105061 A JP 2007-105062 A JP 2007-105063 A JP 2007-222191 A JP 2010-259596 A

  The present invention has been made in view of the above-described conventional problems, and a catalyst for treating an organic halogen compound remaining in a container such as a large-scale transformer in which a large amount of an organic halogen compound needs to be decomposed in one batch of a processing solution. It is an object of the present invention to provide an organic halogen compound decomposition treatment method and decomposition treatment apparatus that can be decomposed without sticking.

  As a result of diligent investigations to solve the above problems, the present inventors have put a filler that is less susceptible to microwaves into the lower part of the catalyst layer of the catalyst filling device for circulating the liquid. The present inventors have found that an organic halogen compound can be detoxified in a treatment time and with a catalyst amount of less than half of the conventional amount, and the present invention has been completed.

  That is, the present invention is as follows.

1) After adding a hydrogen donor and an alkali compound to an organic halogen compound to obtain a mixed solution, the whole or a part of the mixed solution is taken out and circulated to a catalyst filling device, and mixed through the catalyst filling device. In the decomposition method of decomposing organic halogen compounds by irradiating the liquid with microwaves,
The catalyst filling device includes a lower layer of a filler layer and an upper layer of an organic halogen compound decomposition catalyst layer, and the mixture is introduced from above the upper catalyst layer and discharged through the lower filler layer. A method for decomposing organic halogen compounds,
2) The organic halogen compound decomposition treatment method according to 1), wherein the filler is a ceramic ball, a resin ball, or activated carbon.
3) The organic halogen compound decomposition treatment method according to 1) or 2), wherein the filler is a spherical filler having a diameter of 5 to 50 mm,
4) The organic halogen compound decomposition treatment method according to any one of 1) to 3), wherein the ratio of the catalyst to the total bulk volume of the catalyst and the filler is 5 to 50% by volume,
5) The catalyst filling device is disposed in the upper part of the catalyst tank, and the mixed liquid discharged from the catalyst filling apparatus is cooled in a liquid reservoir provided in the lower part of the catalyst tank and then circulated again to the catalyst filling apparatus. -4) The decomposition | disassembly method of the organic halogen compound in any one of.

6) At least (a) a catalyst tank provided with a catalyst filling device in the upper part and a liquid reservoir part provided in the lower part, (b) a liquid circulation system for circulating the liquid in the catalyst tank, and (c) a microwave in the catalyst filling apparatus. A decomposition treatment apparatus comprising a microwave irradiation device for irradiating
A decomposition treatment apparatus for decomposing an organic halogen compound, characterized in that the catalyst filling device is provided by laminating a filler layer on the lower stage and an organic halogen compound decomposition catalyst layer on the upper stage;
7) The decomposition treatment apparatus according to 6), wherein the filler is a ceramic ball, a resin ball, or activated carbon.
8) The decomposition treatment apparatus according to 6) or 7), wherein the filler is a spherical filler having a diameter of 5 to 50 mm,
9) The decomposition treatment apparatus according to any one of 6) to 8), further comprising (d) a cooling unit that cools the liquid stored in the liquid reservoir at the bottom of the catalyst tank.

  According to the present invention, since the liquid to be circulated flows in the order of the catalyst layer and the filler layer provided below the catalyst layer, it is necessary to decompose a large amount of the organic halogen compound in one batch of the processing liquid. A large amount of by-products such as KCl generated during processing of a container such as a transformer is less likely to be accumulated in the catalyst, and the catalyst can be prevented from sticking. As a result, the catalyst life is extended and the amount of catalyst used can be greatly reduced.

  In addition, since the catalyst layer and the filler layer are provided in two stages in the conventional catalyst filling device, the catalyst layer can be formed thinner than the conventional one, and a structure for transmitting microwaves is not required in the catalyst layer. However, since the microwave can reach the entire catalyst layer, and the filler in the lower filler layer can be used any number of times after washing, the apparatus and catalyst costs can be greatly reduced.

  Furthermore, according to the present invention, since the organic halogen compound remaining in the container can be decomposed without being substantially extracted from the container, it is simple and does not depend on the installation location.

It is the schematic explaining the structure of the catalyst filling apparatus of this invention. It is a figure explaining the outline of the usage example of the decomposition processing apparatus of this invention. It is the schematic explaining the structure of the conventional catalyst filling apparatus. It is a graph which shows the relationship between PCB decomposition processing time and PCB density | concentration in an Example and a comparative example.

  The present invention relates to a decomposition treatment method for decomposing and detoxifying an organic halogen compound and a decomposition treatment apparatus used therefor, and after adding a hydrogen donor and an alkali compound to the organic halogen compound to obtain a mixed solution, the mixed solution All or a part of the catalyst is taken out and circulated through the catalyst filling device, and the mixed solution flowing through the catalyst filling device is irradiated with microwaves to decompose the organic halogen compound.

  As a container said by this invention, a pole transformer, a large sized transformer, OF cable oil tank etc. are mentioned, for example, A large sized transformer is used frequently.

  Examples of the organic halogen compound to be decomposed include polychlorinated biphenyls (PCBs) and dioxins, and the type thereof is not particularly limited, but PCBs are preferable. PCBs include PCBs containing dioxins. Examples of commercially available PCBs include KC-200 (main component: biphenyl dichloride), KC-300 (main component: biphenyl trichloride), KC-400 (main component: tetrachloride) manufactured by Kaneka Chemical Co., Ltd. Biphenyl), KC-500 (main component: biphenyl pentachloride), KC-600 (main component: biphenyl bichloride), KC-1000 (KC-500 + benzene trichloride), KC-1300 (KC-300 + dichlorobenzene + tetrachlorobenzene) And Arochlor 1254 (54% Chlorine) manufactured by Mitsubishi Monsite Corporation.

  INDUSTRIAL APPLICABILITY The present invention can be widely used for detoxification treatment of organic halogen compounds, and among them, it can be suitably used for detoxification of containers in which PCBs that are generally difficult to dehalogenate remain. The organic halogen compound is contained alone or in a trace amount in oil such as hydrocarbon oil.

[Catalyst filling device]
FIG. 1 is a schematic view illustrating the configuration of the catalyst filling apparatus of the present invention. 1 is a catalyst filling device, 3 is an upper organic halogen compound decomposition catalyst layer (hereinafter abbreviated as “catalyst layer”), 4 is a lower filler layer, and 5 is a mesh sheet laid on the filler layer. . 6 is a liquid mixture (liquid to be treated) introduced from above the catalyst layer.

  In the upper catalyst layer 3, the ratio of the catalyst forming the catalyst layer and the filler forming the filler layer to the total bulk volume is preferably in the range of 5 to 50% by volume. If the ratio of the catalyst is 5% by volume or more, it is not necessary to frequently exchange the catalyst when decomposing the organic halogen compound. On the other hand, if the ratio of the catalyst is 50% by volume or less, sticking of the catalyst can be prevented. .

  For the lower filler layer 4, fillers such as ceramic balls, resin balls, and activated carbon can be used, and it is more preferable to fill spherical fillers having a diameter of 5 to 50 mm such as ceramic balls and resin balls. Since it is spherical, it is easy to fill and the attached by-products can be easily cleaned. When the diameter is 5 mm or more, the spherical filler does not fall from the lower part of the catalyst filling device, and an appropriate gap is formed in the packed bed, so that the flow of the mixed liquid is not hindered. Further, by setting the diameter to 50 mm or less, it is possible to ensure a gap that prevents the by-product in the filler layer from flowing back to the catalyst layer. Furthermore, by using a spherical filler of uniform size, the voids in the filler layer are also uniform, so that turbulent flow of the mixed liquid in the filler layer is prevented and by-products are retained and accumulated in the catalyst. More preferably, since it flows down smoothly. The fillers can be used alone or in a mixture of different sizes and types. A spherical shape is not necessary as long as the gap can be formed so that the by-product is not retained and accumulated in the catalyst layer. For example, an elliptical shape, a rod shape, a dogleg shape, and the like are conceivable. Metal balls are not preferred because they may spark by microwave irradiation.

  Any catalyst can be used for the upper catalyst layer 3 as long as it can accelerate the dehalogenation reaction of an organic halogen compound (particularly PCB), and the type thereof is not particularly limited. An inorganic catalyst is preferable to an organic catalyst because it has a long catalyst life and is stable even in the presence of an alkali compound.

  The inorganic catalyst is preferably a composite metal oxide, a carbon crystal compound, a metal-supported carbon compound, a metal-supported oxide, a metal-supported composite metal oxide, or a metal oxide from the viewpoint of increasing the dehalogenation efficiency. From the viewpoint of high safety in an alkaline atmosphere, a carbon crystal compound, a metal-supported carbon compound, a metal-supported oxide, and a metal-supported composite oxide are preferable, and a metal-supported carbon compound having high microwave absorption is particularly preferable. These catalysts can be used individually or in combination of 2 or more types. These catalysts may be regenerated catalysts regenerated after use.

  The metal-supported carbon compound may be a carbon compound supporting a metal, but the metal support amount is preferably 0.1 to 20 wt%, more preferably 0.1 to 10 wt% with respect to the total amount of the catalyst. Examples of the supported metal include iron, silver, platinum, ruthenium, palladium, and rhodium. From the viewpoint of increasing the dehalogenation efficiency, palladium, ruthenium, and platinum are preferable, and palladium is particularly preferable. Specific examples of the metal-supported carbon compound include Pd / C (palladium-supported carbon compound), Ru / C (ruthenium-supported carbon compound), Pt / C (platinum-supported carbon compound), and the like.

  Since the catalyst particle size is preferably fixed between the catalyst layer 3 and the filler layer 4 with a mesh sheet 5 or the like, the catalyst particle size is preferably about 75 μm to 10 mm so as not to pass through the mesh sheet. When it exceeds 10 mm, the catalyst specific surface area is insufficient, and when it is less than 75 μm, the mesh is clogged and the differential pressure tends to be high. More preferably, it is 150 micrometers-5 mm. The catalyst particles should be as uniform as possible.

  FIG. 2 is a schematic view showing an embodiment of the present invention, and shows an example of a decomposition process of PCB remaining in a pole transformer (container). In carrying out the decomposition treatment, first, a hydrogen donor and an alkali compound are added into a pole transformer container, and a mixed liquid (processed liquid) of the remaining organic halogen compound, hydrogen donor and alkali compound is prepared. Stir and mix inside the container as needed. It is preferable that the hydrogen donor and the alkali compound are pre-stirred in advance to dissolve the alkali compound in the hydrogen donor. When preparing a mixed liquid, it is necessary to make the volume of the liquid not to overflow from the container.

  In addition, the liquid mixture (processed liquid) of an organic halogen compound, a hydrogen donor, and an alkali compound can also be prepared using containers other than a transformer.

  Examples of the “hydrogen donor” include organic hydrogen donors such as heterocyclic compounds, amine compounds, alcohol compounds, ketone compounds, and alicyclic compounds. Among these compounds, From the viewpoint of safety, alcohol compounds, ketone compounds, and alicyclic compounds are preferred. In particular, alcohol compounds are preferable because they are highly safe, can be obtained at low cost, can be easily controlled, and have high PCB decomposition efficiency. These hydrogen donors can be used alone or in any combination of two or more.

  The alcohol compound may be either an aliphatic alcohol or an aromatic alcohol, and a mono- or polyhydric alcohol having a linear or branched chain can be used. The carbon number of the alcohol compound is preferably in the range of 1 to 12, more preferably in the range of 2 to 9, and still more preferably in the range of 3 to 6. Specific examples of the alcohol compound include, for example, methanol, ethanol, 1-propanol, 2-propanol, n-butanol, s-butanol, t-butanol, 1-pentanol, 2-pentanol, 3-pentanol, 1-hexanol, 2-hexanol, 3-hexanol, 1-heptanol, 2-heptanol, 3-heptanol, 1-octanol, 2-octanol and other aliphatic alcohols, cyclopropyl alcohol, cyclobutyl alcohol, cyclopentyl alcohol, cyclohexyl alcohol And cycloaliphatic alcohols such as cycloheptyl alcohol and cyclooctyl alcohol, and polyhydric alcohols such as ethylene glycol, propylene glycol and decalin diol. Among these, 2-propanol and cyclohexanol are preferable from the viewpoint of decomposition efficiency, and 2-propanol (isopropyl alcohol) is particularly preferable.

  The “alkali compound” can be used without limitation as long as it can promote the dehalogenation reaction of the organic halogen compound, but from the viewpoint of increasing the dehalogenation efficiency, caustic soda, caustic potash, sodium alkoxide, potassium alkoxide. , Calcium hydroxide and the like are preferably used. Among these, caustic soda and caustic potash are particularly preferable from the viewpoint of cost and handling properties. An alkali compound can be used individually or in combination of 2 or more types.

  The addition amount of the alkali compound is preferably 0.1 to 10% (w / v), more preferably 0.2 to 5% (w / v) as a ratio to the hydrogen donor. If the addition amount of the alkali compound is less than 0.1%, the decomposition reaction does not proceed, and if it exceeds 10%, the alkali compound is difficult to dissolve.

  The decomposition treatment apparatus of the present invention circulates at least (a) a catalyst tank 9 in which the above-described catalyst filling apparatus 1 is arranged at the upper part and a liquid reservoir part 8 is provided at the lower part, and (b) the mixed liquid 6 in the catalyst tank 9 (C) microwave irradiation device 13 for irradiating the catalyst filling device 1 with microwaves, (d) cooling means for cooling the mixed solution 6 stored in the liquid reservoir 8 below the catalyst tank 9 14. As each apparatus except the catalyst filling apparatus 1 described above, an apparatus described in JP 2009-110880 A can be preferably used.

[Catalyst tank]
The catalyst tank 9 is provided for installing the catalyst filling device 1 and for storing the mixed liquid 6 circulated through the catalyst filling device 1. From the viewpoint of space saving, the catalyst tank 9 is provided with the catalyst filling device 1 in the upper part, and the liquid mixture 6 circulated through the catalyst filling apparatus 1 is provided in the lower part of the catalyst tank 9 with a liquid reservoir 8. After being stored in the liquid reservoir 8 and discharged from a discharge port 9 b provided on the bottom surface of the liquid reservoir 8, it can be returned to the catalyst tank 9 from the inlet 9 a via the liquid circulation system 10. ing.

  The mixed liquid 6 returned to the catalyst tank 9 is circulated between the liquid reservoir 8 of the catalyst tank 9 and the catalyst filling apparatus 1 by being supplied to the catalyst filling apparatus 1 again. The arrows in FIG. 2 indicate the general flow direction of the mixed liquid 6 that has circulated through the catalyst filling device 1. When the mixed liquid 6 circulated through the catalyst filling device 1 is discharged from the discharge port 9b provided on the side surface of the liquid reservoir 8, and then returned to the catalyst filling device 1 via the liquid circulation system 10, the valve 10a is Close and open valve 10d.

  The catalyst filling apparatus 1 has a cartridge type because it can be replaced quickly and easily when the decomposition rate of the organic halogen compound is reduced during the decomposition process, and the post-treatment of the catalyst after the process is easy. preferable. By doing so, the mixed liquid 6 that has flowed through the catalyst filling device 1 flows out of the cartridge and then flows down from the liquid overflow port 2 to the liquid reservoir 8 when it reaches a predetermined liquid volume. The contact time between the liquid 6 and the catalyst layer 3 can be maintained.

  By installing the catalyst tank 9 above the pole transformer, the mixed liquid 6 after passing through the catalyst filling device 1 can be returned to the pole transformer by its own weight. Since the cross-sectional area can be appropriately designed according to the inner diameter of the pole transformer, it is easy to cope with various containers.

[Liquid circulation system]
The liquid circulation system 10 is for circulating the mixed liquid 6 in the catalyst tank 9. These liquid circulation systems 10 can use general devices and combinations such as pumps, pipes, valves, etc. (10a to 10e, etc.). The liquid circulation system 10 can also be used when the mixed solution 6 in the container is sent to the catalyst filling device 1.

  The circulation of the mixed solution 6 is performed until the organic halogen compound in the mixed solution 6 becomes a predetermined concentration or less. A sampling valve (10a) is appropriately provided in the liquid circulation system 10, and the mixed liquid 6 is sampled and analyzed from time to time, whereby the organic halogen compound concentration in the mixed liquid 6 can be measured.

[Microwave irradiation equipment]
The microwave irradiation device 13 is for irradiating the catalyst layer 3 of the catalyst filling device 1 with microwaves. Although the installation place of the microwave irradiation apparatus 13 is not specifically limited, space saving can be achieved if it is provided above the catalyst filling apparatus 1. The mixed solution 6 flowing through the catalyst filling device 1 comes into contact with the catalyst layer 3 heated by the microwave oscillated from the microwave irradiation device 13. Thereby, the organic halogen compound in the mixed solution 6 is rapidly decomposed. When the filler layer 4 is circulated, by-products such as KCl generated by decomposition adhere to the filler, so that the catalyst layer 3 can be prevented from sticking.

  The microwave irradiation device 13 is provided with a temperature controller 12 (with a PID control function) for temperature measurement and temperature control of the mixed solution 6 in the catalyst filling device 1 in order to level the microwave irradiation amount. preferable. Based on the temperature of the liquid mixture 6 detected by the temperature sensor 11 and the temperature set by the temperature controller 12, the output of the microwave irradiation device 13 is PID-controlled, so that the liquid temperature of the liquid mixture 6 is continuously radiated. Can be maintained at a substantially constant temperature.

  The frequency of the microwave to be irradiated is preferably 1 to 300 GHz, and in the frequency range of less than 1 GHz or more than 300 GHz, heating of the catalyst and the hydrogen donor becomes insufficient. As the microwave oscillator, a microwave oscillator such as a magnetron, a microwave oscillator using a solid element, or the like can be used as appropriate.

  The microwave irradiation method is not limited and can be performed continuously or intermittently. However, from the viewpoint of rapid processing, continuous irradiation or irradiation for as long as possible is desirable.

[Cooling means]
The cooling means 14 is for cooling the mixed liquid 6 stored in the liquid reservoir 8 below the catalyst tank 9, and is preferably provided at an appropriate location of the liquid reservoir 8. FIG. 2 shows an example in which a cooling coil is installed as a cooling means 14 in the liquid reservoir 8. A cooling water circulation device 15 such as a general heat exchanger to which a cooling medium is supplied from a cooling coil cold heat source is used, and the cold water supplied from the device 15 to the cooling coil inlet through a line comes into contact with the mixed liquid 6. After that, the mixed liquid 6 is cooled by returning to the cooling water circulation device 15 through the line from the outlet of the cooling coil.

  The installation location and the installation form of the cooling means 14 are not particularly limited. For example, as shown in the drawing, the cooling means 14 is arranged so as to circulate around the catalyst filling device 1 in order to reduce the cooling efficiency. It is more preferable than this point. Since the microwave is blocked by the catalyst filling device 1 and does not reach the liquid reservoir 8, the liquid reservoir 8 is not subject to heating by the microwave.

  When the organic halogen compound is decomposed using the decomposition processing apparatus of the present invention, the mixed liquid 6 is continuously circulated through the catalyst filling apparatus 1 while being irradiated with microwaves to decompose the organic halogen compound. Therefore, the microwave irradiation amount is adjusted while the temperature sensor 11 detects the temperature of the mixed liquid 6 when it flows through the catalyst filling device 1.

  The reaction temperature (that is, the temperature of the mixed solution 6) is preferably low in order to make it difficult to generate by-products such as dioxins, but in consideration of the decomposition rate, it is preferably from normal temperature to 100 ° C. When adopting, is preferably 40 to 80 ° C. When reaction temperature exceeds 100 degreeC, it becomes easy to produce | generate a by-product and it will also be inferior to economical efficiency.

  When the cooling means 14 is employed, the temperature of the liquid mixture 6 in the liquid reservoir 8 is maintained at a temperature lower than the reaction temperature by at least 5 ° C., preferably 10 ° C. or more, particularly preferably about 10-30 ° C. It is preferable. If the mixed liquid 6 is cooled too much, the fluidity of the mixed liquid 6 is lowered, and it may be difficult to return to the pole transformer, or clogging may occur. Or it becomes difficult to maintain and control the reaction temperature by microwave irradiation.

  The time for which the mixed solution 6 is allowed to flow through the catalyst filling device 1 is not particularly limited, and is performed until the organic halogen compound in the mixed solution 6 is equal to or lower than a predetermined processing reference value. If the catalyst activity is reduced during the process, the catalyst filling device 1 can be replaced as necessary.

  By performing the above decomposition treatment, the organic halogen compound can be rendered harmless. After completion of the decomposition reaction, the container can be treated by extracting the mixed liquid 6 from the container through an extraction pump or a drain valve.

  According to the organic halogen compound decomposition treatment method of the present invention, the organic halogen compound is decomposed and dehalogenated by heating with microwaves without applying hydrogen gas or heat from the outside. Although the mechanism is not clear, it is considered that the alkali compound promotes the dehalogenation reaction of the organic halogen compound, and the hydrogen radical from the hydrogen donor enters therein. Even at a site such as a transformer store, it is possible to safely treat difficult-to-decompose organic halogen compounds such as PCB simply by carrying out a circulation operation without preparing a new heating source.

  EXAMPLES Next, although an Example demonstrates this invention concretely, this invention is not limited only to a following example. In the following examples and the like, “mass%” is abbreviated as “%” unless otherwise specified.

(Comparative Example 1)
A predetermined amount of insulating oil (KC-1000) extracted from a large transformer was added to isopropyl alcohol (IPA), and KOH; 600 g was further added to obtain a liquid to be treated having a PCB concentration of 10,000 ppm.

On the other hand, a catalyst (average particle diameter of about 1 mm) in which 5% palladium (Pd) was supported on granular activated carbon (trade name: Diahop 008) was prepared and dried at 70 ° C. for 8 hours. 2 kg of this catalyst was put into a catalyst filling apparatus, and the upper and lower sides were sandwiched between 100 mesh nets, and the catalyst was filled to form a catalyst layer (cross-sectional area: 330 cm ² ). In this catalyst layer, six structures made of Teflon (registered trademark) were arranged, and the catalyst layer was configured as shown in FIG.

  A gear pump manufactured by EFNIC (ModelGPE-031, 12V DC) is attached to the outside of the container, a Teflon (registered trademark) tube having an inner diameter of 6 mm is attached to each pump, and one end is immersed in the bottom of the liquid to be treated. This end was connected to an inlet provided in the upper part of the catalyst filling device. The liquid to be treated was extracted from the container with a pump and circulated through the container while continuously passing through the catalyst filling device at a rate of 1 L / min. In the meantime, the temperature of the liquid to be treated was continuously maintained at 60 ° C. by setting the temperature controller to 60 ° C. and continuously irradiating microwaves having a frequency of 2.45 GHz and a maximum output of 1.5 kW while controlling PID.

  On the other hand, the liquid flowed out to the liquid storage part provided in the bottom part of the catalyst tank was cooled with the cooling coil. The temperature of the effluent was 40 ° C.

  The liquid to be treated treated with the catalyst filling device was returned to the container by opening a valve of the pipe, and the liquid to be treated in the container was periodically sampled. The PCB concentration in the sampled liquid to be treated was analyzed using a gas chromatography mass spectrometer QP5050AW (hereinafter referred to as “GC-MS”) manufactured by Shimadzu Corporation using DB1 (manufactured by J & W Scientific) as a capillary column. did. When the PCB concentration in the liquid to be treated did not fall below the target of 0.5 ppm, the operation of returning the liquid to be treated to the catalyst filling device was circulated and circulated again and then returned to the container.

Example 1
A predetermined amount of insulating oil (KC-1000) extracted from a large transformer was added to isopropyl alcohol (IPA), and KOH; 600 g was further added to obtain a liquid to be treated having a PCB concentration of 10,000 ppm.

4 kg of ceramic balls having a diameter of 10 mmφ were put in a catalyst filling device to form a filler layer, and a 100 mesh Teflon (registered trademark) mesh sheet was laid thereon. 800 g of a catalyst in which 5% palladium (Pd) is supported on granular activated carbon (trade name: Diahop 008) on a Teflon (registered trademark) mesh sheet (dried at 70 ° C. for 8 hours) And a catalyst layer (cross-sectional area: 330 cm ² ) was formed. Bulk volume ratio of catalyst layer: about 40%.

  A gear pump manufactured by EFNIC (ModelGPE-031, 12V DC) is attached to the outside of the container, a Teflon (registered trademark) tube having an inner diameter of 6 mm is attached to each pump, and one end is immersed in the bottom of the liquid to be treated. This end was connected to an inlet provided in the upper part of the catalyst filling device. The liquid to be treated was extracted from the container with a pump and circulated through the container while continuously passing through the catalyst filling device at a rate of 1 L / min. Meanwhile, the temperature of the liquid to be treated was maintained at 60 ° C. by setting the temperature controller to 60 ° C. and continuously irradiating microwaves having a frequency of 2.45 GHz and an output of about 400 W to 500 W with PID control.

  On the other hand, the liquid flowed out to the liquid storage part provided in the bottom part of the catalyst tank was cooled with the cooling coil, and the liquid temperature was 40 degreeC.

  The liquid to be treated treated with the catalyst filling device was returned to the container by opening a valve of the pipe, and the liquid to be treated in the container was periodically sampled. The PCB concentration in the sampled solution to be treated was analyzed using GC-MS using DB1 (manufactured by J & W Scientific) as a capillary column. When the PCB concentration in the liquid to be treated did not fall below the target of 0.5 ppm, the operation of returning the liquid to be treated to the catalyst filling device was circulated and circulated again and then returned to the container.

(Example 2)
After the decomposition treatment of Example 1 was completed and the treatment liquid was once extracted, the same amount of KC-1000, KOH, and IPA as in Example 1 was placed in the liquid reservoir, and the decomposition treatment was performed in the same manner.

(Example 3)
In Example 1, 1.5 kg of activated carbon having a diameter of about 1 mmφ was placed in a catalyst filling device to form a filler layer, and a 100 mesh Teflon (registered trademark) mesh sheet was laid, and a Teflon (registered trademark) mesh sheet was laid. On top of this, 500 g of granular activated carbon (trade name: Diamond Hope 008) supporting 5% palladium (Pd) (average particle size of about 1 mm, dried at 70 ° C. for 8 hours) is added, and the catalyst layer (cut off) The decomposition treatment was performed in the same manner as in Example 1 except that the area was 330 cm ² ). Bulk volume ratio of catalyst layer: about 25%.

  FIG. 4 shows the relationship between the processing time and PCB concentration in Examples and Comparative Examples.

  As is clear from FIG. 4, in this example, the PCB was decomposed in the same decomposition processing time as in Comparative Example 1 even though the amount of catalyst used was 25 to 40% of Comparative Example 1. I was able to. From the results of Example 2, it can be seen that the catalyst filling device having the configuration of the present invention can withstand repeated use.

  In Example 3 filled with activated carbon, a PCB concentration of 1 ppm or less could not be achieved in a treatment time of 50 hours in the second decomposition test.

  According to the present invention, a contaminated container can be detoxified easily and at low cost under normal pressure conditions. Therefore, if the decomposition processing apparatus of the present invention is installed at a site such as a transformer storage, A dehalogenation treatment can be performed. Therefore, according to the present invention, since a large amount of PCB can be rendered harmless on a practical scale, the practical value of the present invention is extremely great.

DESCRIPTION OF SYMBOLS 1 Catalyst filling apparatus 1 'Catalyst filling apparatus 2 Liquid overflow port 3 Organohalogen compound decomposition | disassembly catalyst layer 4 Filler material layer 5 Mesh sheet 6 Liquid mixture (processed liquid)
DESCRIPTION OF SYMBOLS 7 Structure 8 Liquid reservoir 9 Catalyst tank 9a Inlet 9b Outlet 10 Liquid circulation system 11 Temperature sensor 12 Temperature controller 13 Microwave irradiation device 14 Cooling means 15 Cooling water circulation device

Claims (9)

After adding a hydrogen donor and an alkali compound to the organic halogen compound to make a mixed solution, all or part of the mixed solution is taken out and circulated to the catalyst filling device, and the mixed solution flowing through the catalyst filling device In a decomposition treatment method for decomposing an organic halogen compound by irradiating microwaves,
The catalyst filling device includes a lower layer of a filler layer and an upper layer of an organic halogen compound decomposition catalyst layer, and the mixture is introduced from above the upper catalyst layer and discharged through the lower filler layer. A method for decomposing an organic halogen compound.   The organic halogen compound decomposition treatment method according to claim 1, wherein the filler is a ceramic ball, a resin ball, or activated carbon.   The method for decomposing an organic halogen compound according to claim 1 or 2, wherein the filler is a spherical filler having a diameter of 5 to 50 mm.   The decomposition | disassembly processing method of the organic halogen compound in any one of Claims 1-3 whose ratio of the catalyst with respect to the total bulk volume of a catalyst and a filler is 5-50 volume%.   The catalyst filling device is disposed in the upper portion of the catalyst tank, and the mixed liquid discharged from the catalyst filling device is cooled in a liquid reservoir provided in the lower portion of the catalyst tank, and then circulated again to the catalyst filling device. 5. The decomposition method for an organic halogen compound according to any one of 4 above. At least (a) a catalyst tank provided with a catalyst filling device at the top and a liquid reservoir at the bottom, (b) a liquid circulation system for circulating the liquid in the catalyst tank, and (c) microwave irradiation to the catalyst filling device A decomposition treatment apparatus comprising a microwave irradiation device for performing,
A decomposition treatment apparatus for decomposing an organic halogen compound, characterized in that the catalyst filling apparatus is provided with a filler layer in a lower layer and an organic halogen compound decomposition catalyst layer in an upper layer.   The decomposition processing apparatus according to claim 6, wherein the filler is a ceramic ball, a resin ball, or activated carbon.   The decomposition processing apparatus according to claim 6 or 7, wherein the filler is a spherical filler having a diameter of 5 to 50 mm.   Furthermore, (d) the decomposition processing apparatus in any one of Claims 6-8 which comprises the cooling means which cools the liquid stored in the liquid storage part of a catalyst tank lower part.

Images