JP3976332B1 - Decomposition method of high-concentration organochlorine compounds - Google Patents

Abstract

A method for decomposing a high-concentration organochlorine compound, which can reuse the reaction solution after the decomposing treatment to reduce the processing cost in order to further improve the efficiency of the decomposition treatment of the high-concentration organochlorine compound. provide.
An organic chlorine compound containing 50% by mass or more of a polychlorinated biphenyl and a hydrogen donating solvent, wherein the column is packed with at least one catalyst selected from a carbon crystal compound and a compound having a metal supported on a carrier. An organic chlorine compound is dechlorinated while circulating a reaction solution containing an alkali compound and an alkali compound in a column packed with the catalyst, and a new organic chlorine compound and the organic chlorine compound are added to the solution after the dechlorination reaction. 0.8 to 1.5 equivalents (against chlorine) of an alkali compound is added, and the reaction solution is dechlorinated while being reused.
[Selection] Figure 1

Description

  The present invention relates to a method for decomposing a high concentration organochlorine compound that dechlorinates a high concentration organochlorine compound to render it harmless.

  Among various chlorinated organic compounds, polychlorinated biphenyl (hereinafter sometimes abbreviated as PCB) is extremely harmful to living bodies including the human body. Therefore, it was designated as a specified chemical substance in 1973, and its production, importation, Use is prohibited. However, after that, tens of thousands of tons of PCBs are left untreated without determining an appropriate disposal method. PCB decomposes PCB safely technically because chlorinated dibenzo-p-dioxin (PCDD) and dibenzofuran (PCDF), which are highly toxic dioxins, are by-produced at high temperature (30 to 750 ° C) decomposition. This is difficult, and various safe and efficient decomposition methods for PCBs have been studied for many years.

  Decomposition treatment of organochlorine compounds is broadly divided into decomposition treatment of high-concentration organochlorine compounds such as PCB oil used as insulating oil, and decomposition treatment of low-concentration organochlorine compounds mixed in mineral oil when insulating oil is replaced. . For the decomposition treatment of the high-concentration organochlorine compound, a method is generally employed in which the dechlorinated chlorine is neutralized and removed by reacting with a reducing agent using a reduction catalyst.

  For example, in Patent Document 1, harmful organic chlorine compounds are dechlorinated by irradiating microwaves while blowing hydrogen gas into a mixed system containing activated carbon supporting platinum and an aromatic chlorine compound (parachlorophenol or the like). A method has been proposed. This method is characterized by irradiating microwaves in the presence of a reducing substance. In this example, a suspension of a catalyst in an aqueous parachlorophenol solution is placed in a 100 ml reaction flask, and hydrogen gas is supplied. It reacts by irradiating microwaves while blowing.

  Further, in Patent Document 2, after adding a catalyst made of a carbon compound carrying a predetermined amount of alkali and a metal such as platinum, palladium, rhodium, etc., to 2-propanol in which PCB is dissolved, A method is described in which PCB is decomposed by heating to the boiling point of 2-propanol (83 ° C.) while stirring and performing a decomposition reaction under reflux conditions for 120 minutes or 180 minutes.

Further, in Patent Document 3, as a method proposed by the present inventors, microwaves are irradiated to a column while flowing a mixed solution of PCB, an alcohol having a boiling point of 100 ° C. or less and an alkali through a column packed with a catalyst. Thus, a method of dechlorinating PCB at low temperature is disclosed.
JP 2001-19646 A (Claim 1, paragraph number 0009, etc.) JP-A-8-266888 (Claims 1-4, paragraph numbers 0012 to 0013, etc.) Japanese Patent No. 3678740 (claims 1-4, paragraph numbers 0049-0050, etc.)

  However, since the methods disclosed in Patent Documents 1 and 2 are batch-type dechlorination methods in which the catalyst is dispersed in the reaction solution, it is necessary to separate and recover the deactivated catalyst after the reaction is completed. It becomes. On the other hand, it is theoretically possible to repeat the dechlorination reaction operation while adding the catalyst and PCB using the same reaction vessel, but the amount of catalyst in the reaction vessel gradually increases by repeating the same operation. , Impeding the stirring operation or preventing the progress of the dechlorination reaction. Therefore, these methods are difficult to say as low-cost processing methods.

  In addition, the cleaning solvent used for cleaning the pole transformer filled with PCB-mixed oil and the solvent used for the PCB decomposition treatment reaction are generally recovered by distillation and then reused for the decomposition treatment. Has been done. However, since the solvent recovery cost (distillation cost) increases if the absolute amount of the solvent is large, such a recycling method cannot be a drastic method.

  The method disclosed in Patent Document 3 does not require the operation of separating and recovering the catalyst, and it is only necessary to replace the deactivated catalyst. Therefore, a continuous treatment operation is possible, but a decomposition rate of a certain value or more is always achieved. To do this, 100 times the volume of 2-propanol is required per PCB. Therefore, if a large amount of solvent is used, the solvent cost and the recovery cost increase, which has a problem that the reaction processing efficiency is inferior.

  The present invention was made in order to further improve the efficiency of the decomposition treatment of high-concentration organochlorine compounds, and the high-concentration organochlorine compounds that can reuse the reaction solution after the decomposition treatment and reduce the processing cost It aims at providing the decomposition method of this.

  As a result of intensive studies to solve the above problems, the present inventors conducted a dechlorination reaction while circulating a reaction solution containing a high concentration of an organic chlorine compound and a specific agent through a catalyst column, and after the dechlorination reaction It was found that the above-mentioned object can be achieved by adding a high-concentration organochlorine compound and a predetermined amount of an alkali compound to the solution and dechlorinating the solution, thereby completing the present invention.

That is, the present invention is as follows.
1) At least one catalyst selected from a carbon crystal compound and a compound having a metal supported on a carrier is packed in a column, an organic chlorine compound containing 50% by mass or more of polychlorinated biphenyl, a hydrogen donating solvent, and an alkali A reaction solution containing a compound , wherein the reaction solution containing 0.2 to 5 wt% of the organochlorine compound (to a hydrogen donating solvent) is passed through the column packed with the catalyst while dechlorinating the organochlorine compound. In the solution after the dechlorination reaction, 0.2 to 5 wt% (to hydrogen donating solvent) of a new organochlorine compound and 0.8 to 1.5 equivalents (to chlorine) of the organochlorine compound. A method for decomposing a high-concentration organochlorine compound, wherein an alkali compound is added and dechlorination is performed while reusing the reaction solution;
2) The method for decomposing a high-concentration organochlorine compound according to 1), wherein the reaction solution is reused at least twice.
3) The method for decomposing a high-concentration organochlorine compound according to 1) or 2) above, wherein the catalyst is replaced at a frequency of 0 to every time the reaction solution is reused.
4 ) The method for decomposing a high-concentration organochlorine compound according to any one of 1) to 3 ) above, wherein the reaction solution in the catalyst packed column is irradiated with microwaves when decomposing the organochlorine compound.
5 ) The method for decomposing a high-concentration organochlorine compound according to any one of 1) to 4 ) above, wherein the reaction solution is continuously passed through a catalyst packed column,
6 ) The decomposition method of the high-concentration organochlorine compound according to any one of 1) to 5 ), wherein the alkali compound is NaOH or KOH,
7 ) The method for decomposing a high-concentration organochlorine compound according to any one of 1) to 6 ), wherein the catalyst is a palladium-supported carbon compound, and
8 ) The method for decomposing a high-concentration organochlorine compound according to any one of 1) to 7 ) above, wherein the hydrogen-donating solvent is isopropyl alcohol.

  According to the method for decomposing a high-concentration organochlorine compound of the present invention, since the reaction solution (solvent) can be reused, a batch-by-batch distillation step for collecting and reusing the solvent used in the reaction becomes unnecessary. The reaction solution can be reused at least twice. Moreover, since the amount of the solvent used for the whole process decreases after the reuse, the distillation cost for the reuse can be reduced.

  Since the reaction solution can be circulated while being circulated through the catalyst filling device and irradiated with microwaves as necessary, the organochlorine compound can be decomposed in a short time. Furthermore, by continuously circulating the reaction solution through the catalyst packed column, decomposition at room temperature progresses even at night when microwave irradiation is not performed. By rocking, clogging of the catalyst packed column can be prevented.

  Hereinafter, the decomposition method of the high concentration organochlorine compound according to the present invention will be described in detail with reference to the drawings.

In the method for decomposing a high-concentration organochlorine compound of the present invention, a column is packed with at least one catalyst selected from a carbon crystal compound and a compound in which a metal is supported on a carrier, and contains 50% by mass or more of polychlorinated biphenyls. A reaction solution containing an organochlorine compound, a hydrogen donating solvent, and an alkali compound, the reaction solution containing 0.2 to 5 wt% of the organochlorine compound (to a hydrogen donating solvent) filled with the catalyst The organochlorine compound is dechlorinated while being circulated, and 0.2 to 5 wt% of a new organochlorine compound (to a hydrogen-donating solvent) and 0. 8 to 1.5 equivalents (against chlorine) of an alkali compound is added, and the reaction solution is dechlorinated while being reused.

  The organochlorine compound to be dechlorinated in the decomposition method of the present invention is an organochlorine compound containing 50% by mass or more of polychlorinated biphenyl, and is mainly an oil tank for pole transformers, large transformers, capacitors, and oil insulated cables. The thing used as insulating oil etc. becomes the object. Specifically, polychlorinated biphenyl or a mixture of polychlorinated biphenyl and a chlorinated aromatic compound can be used.

  Examples of polychlorinated biphenyls (PCBs) include KC-200 (main component: biphenyl dichloride), KC-300 (main component: biphenyl trichloride), and KC-400 (main component: Kaneka Chemical Co., Ltd.). Biphenyl tetrachloride), KC-500 (main component: biphenyl bichloride), KC-600 (main component: biphenyl hexachloride), KC-1000 (mixture of KC500 / TCB = 60/40 (mass ratio)), KC- 1300 (mixture of KC-300 + DCB + tetrachlorobenzene) and Aroclor 1254 (54% Chlorine) manufactured by Mitsubishi Monsite Corporation.

  In the case of a mixture of polychlorinated biphenyl and a chlorinated aromatic compound, the mixing ratio is not particularly limited, but is generally polychlorinated biphenyl / chlorinated aromatic compound = 9/1 to 5/5 (mass ratio). This is because when the ratio of polychlorinated biphenyl / chlorinated aromatic compound is less than 9/1, the viscosity of the oil becomes high, whereas when the ratio exceeds 5/5, the insulation performance decreases. Examples of the chlorinated aromatic compound include those in which a chlorine atom is substituted on the aromatic compound, for example, trichlorobenzene (TCB), dichlorobenzene (DCB), tetrachlorobenzene, etc., but generally trichlorobenzene (TCB). ) Is frequently used.

  FIG. 1 is an explanatory view showing a preferred example of the decomposition method of the present invention. A hydrogen donating solvent (isopropyl alcohol: IPA)), an alkali compound (KOH), and an organic chlorine compound (PCB) are added to a reaction tank 20. The reaction solution 10 is obtained. This is brought into contact with the catalyst by circulating pump 21 through piping 22 and passing through catalyst packed column 35 installed in microwave device 30 to dechlorinate PCB. The reaction solution after flowing through the column is returned to the reaction tank 20 through the pipe 23. 1 may be provided with a cluster destruction device such as an ultrasonic generator, a cooling device such as a condenser, a PCB concentration measuring device such as a dielectric constant meter, and the like.

  As the hydrogen donating solvent, one or more selected from a heterocyclic compound, an amine compound, an alcohol compound, a ketone compound, an alicyclic compound, and the like can be used, but among these, from the viewpoint of safety Alcohol compounds, ketone compounds and alicyclic compounds are preferred. In particular, alcohol compounds are preferred from the viewpoints of safety, low cost, easy availability, easy reaction control, and high PCB decomposition efficiency. Preferred alcohols include, for example, ethanol, 1-propyl alcohol, isopropyl alcohol, t-butanol, cyclohexanol, etc., but secondary alcohols such as isopropyl alcohol and cyclohexyl alcohol are more preferred, and isopropyl alcohol is most preferred. .

  As the alkali compound, NaOH, KOH, sodium alkoxide, potassium alkoxide, calcium hydroxide and the like can be used alone or in combination of two or more. Among these, NaOH or KOH is preferable from the viewpoints of cost and handling properties.

The concentration of the organic chlorine compound at the time of preparing the first reaction solution is 0.2 to 5 wt%, most preferably 0.2 to 2 wt% with respect to the hydrogen donating solvent. If the concentration of the organochlorine compound is too high, the number of times the solvent is reused decreases and the time required for decomposition increases, which is not economical, and if the concentration is too low, the efficiency of dechlorination deteriorates. The alkali compound is preferably used in an amount of 1.0 equivalent or more with respect to the chlorine of the organic chlorine compound, and more preferably 1.0 to 1 from the viewpoint of suppressing the influence by the formation of by-product salt as much as possible and increasing the decomposition efficiency. .5 equivalents.

  As the catalyst, at least one selected from a carbon crystal compound and a compound in which a metal is supported on a carrier is used. The above catalyst is preferable because it can promote the dechlorination reaction of organochlorine compounds (particularly PCB), is stable even in the presence of alkali compounds, is safe in an alkaline atmosphere, and exhibits high activity against microwaves. Can be used. You may use a catalyst individually or in combination of 2 or more types. Among these catalysts, a compound in which a metal is supported on a carrier is preferable.

  Examples of the carbon crystal compound include graphite, carbon nanotubes (both including and not including metal), fullerene, and the like. In the case of a compound in which a metal is supported on a carrier, examples of the carrier include carbon such as activated carbon and graphite, silica gel, metal oxide such as alumina and zeolite, composite metal oxide, and resin such as polyethylene. Among these, a metal-supported carbon compound in which a metal is supported on a carbon support is preferable from the viewpoints of high dechlorination efficiency and high stability in an alkaline atmosphere.

  The metal-supported carbon compound may be a carbon compound supporting a metal, but the metal support amount is 1 to 20 wt%, preferably 5 to 10 wt%, based on 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 dechlorination efficiency, palladium, ruthenium, and platinum are preferable, and palladium is more 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.

  The shape of the catalyst may be granular or honeycomb. In the case of granular, it is necessary to fix the upper and lower sides of the column with a mesh or the like, and the particle diameter in that case is preferably 75 μm to 10 mm. When it exceeds 10 mm, the specific surface area is insufficient, and when it is less than 75 μm, the mesh is clogged and the differential pressure becomes high. More preferably, it is 150 μm to 5 mm. The catalyst particles should have the same particle size as possible.

  The amount of catalyst used in the reaction system varies depending on the configuration of the column and the liquid flow rate, but it is usually preferable to use 5 to 50% by weight with respect to the total amount of the reaction solution.

  The shape, size, and installation location of the catalyst packed column in the microwave device are not particularly limited, and may be installed at a position where microwave irradiation is possible. The catalyst packed column may be a removable cassette type. The catalyst can be exchanged at a frequency of 0 to every time the hydrogen donating solvent is reused, and the exchange frequency is preferably determined by the PCB concentration of the treatment liquid to be decomposed. In the method of dispersing the catalyst in the reaction solution, it is necessary to separate and recover the catalyst, but in the present invention, it is not necessary to separate the catalyst from the reaction solution by circulating the reaction solution through the catalyst packed column. The reaction solution can be easily reused repeatedly.

  Since the catalyst packed column 35 is installed in the microwave device 30, microwaves can be irradiated as necessary. When the microwave device is turned on, the reaction solution flowing through the catalyst layer comes into contact with the catalyst heated by the irradiated microwave. Therefore, since the reaction solution flowing through the catalyst layer comes into contact with the catalyst activated by the microwave, the organochlorine compound is decomposed at a much faster rate than when it is brought into contact in an unheated state. On the other hand, when the microwave device is turned off, the reaction solution flowing through the catalyst layer comes into contact with the catalyst at room temperature, so that the organic chlorine compound gradually decomposes at a relatively low speed. The reaction temperature is preferably in the range of 10 ° C to 200 ° C, more preferably 10 to 80 ° C. When the reaction temperature is less than 10 ° C., the decomposition reaction is insufficient. On the other hand, when the reaction temperature exceeds 200 ° C., the dechlorination reaction proceeds sufficiently, but by-products are easily generated, and the economy is inferior. The reaction time is not particularly limited, and it may be performed until the dechlorination reaction is sufficiently advanced and rendered harmless.

  The output, frequency, and irradiation method of the microwave to be irradiated are not particularly limited, and may be electrically controlled so that the reaction temperature can be maintained within a predetermined range. When the output is too low, the amount of hydrogen generated is reduced, and when the output is too high, the microwave utilization rate is deteriorated. Therefore, the range is 10 W to 20 kW while being electrically controlled, preferably 40 W to 5 kW. To do. The microwave frequency is preferably 1 to 300 GHz, and in the frequency range of less than 1 GHz or more than 300 GHz, the catalyst and the hydrogen donor are not sufficiently heated. Microwave irradiation may be either continuous irradiation or intermittent irradiation.

  In the initial decomposition process, the decomposition process is temporarily stopped when the PCB concentration in the reaction solution becomes equal to or lower than the regulation value. Then, after the second time, the solution after the dechlorination reaction is added with a new organochlorine compound and 0.8 to 1.5 equivalents (relative to chlorine), preferably 1.0 to 1.3 equivalents ( Dechlorination is carried out by the above method while adding an alkali compound (to chlorine) and reusing the reaction solution. When only a new organochlorine compound is added without adding an alkali compound, the desorbed chlorine cannot be captured and the decomposition reaction is in an equilibrium state, so that the dechlorination reaction does not proceed. On the other hand, even if the amount of the alkali compound added is too large, the reaction reaches its peak, resulting in poor economic efficiency.

  In addition, the alkali compound can be selected from the above compounds and used, but selecting one having high solubility in the hydrogen-donating solvent can prevent clogging when the reaction solution is passed through the catalyst packed column. It is preferable from the point which can prevent. The alkali compound may be added as a simple substance or may be added after being dissolved in a small amount of solvent.

  By repeatedly using the reaction solution, the amount of by-products such as biphenyl and KCl gradually increases in the solution. However, the reaction solution is repeatedly used unless clogging or the like occurs in the catalyst packed column. Can be used. In this case, it is preferable to replace the catalyst while checking the degree of deterioration. The catalyst replacement frequency can be selected from 0 to every time the reaction solution is reused. Therefore, the catalyst may be replaced every time a new organochlorine compound is added. Alternatively, the catalyst may be replaced once every three times. There is no limit to the number of times the reaction solution can be reused, but it is desirable that it be at least 2 times, preferably 3 times or more in consideration of economy. In this case, the catalyst may be used continuously or replaced with a new catalyst.

  FIG. 2 is a schematic flow diagram of the decomposition method of the present invention. Since the reaction solution after the decomposition treatment contains solvent, solvent decomposition products, by-product salt (KCl), biphenyl, etc., after storing the solution in the reaction tank, the treated solution etc. is industrially discarded. Dispose of as waste or recycle.

(Function)
According to the method for decomposing an organic chlorine compound of the present invention, the organic chlorine compound is decomposed and dechlorinated without newly adding a solvent. Although the mechanism is not clear, the alkali compound promotes the dechlorination reaction of the organochlorine compound, and hydrogen radicals from the solvent (hydrogen donor) that exists in excess enter it. Chlorination proceeds. Therefore, even if the decomposition rate is slow, if it is a site such as a transformer storage, PCB can be processed by simply leaving it without preparing a new heating source, etc. Microwave irradiation can also be performed as necessary.

  EXAMPLES Next, although an Example demonstrates this invention concretely, this invention is not limited only to a following example.

Example 1
PCB (mixture of KC-400 / trichlorobenzene) 1.3 ml (PCB concentration 1 wt% / IPA), KOH flakes 1.99 g (1.2 eq. Vs. chlorine), 148.7 ml isopropyl alcohol (IPA) at 3000 rpm homo A mixture obtained by stirring for 20 minutes with a mixer was introduced into a five-necked flask (hereinafter referred to as “reaction vessel”) having an internal volume of 200 ml. After introducing these, the inside of the reaction vessel was replaced with nitrogen gas.

  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. 24 g of this catalyst was put into a catalyst filling device installed in a microwave generator, and the catalyst was filled by sandwiching the top and bottom with a mesh of 100 mesh. While stirring the inside of the reaction tank with a magnetic stirrer, the mixed solution in the reaction tank was extracted with a pump and continuously circulated at a rate of 10 ml / min through the catalyst filling device equipped with an optical fiber thermometer. Returned and circulated at room temperature. Meanwhile, microwaves having a frequency of 2.45 GHz and a maximum output of 700 W were continuously irradiated while being electrically controlled, and the reaction temperature was maintained at 60 ° C. Nitrogen gas was allowed to flow at 50 ml / min during the reaction.

  The PCB concentration in the mixed solution circulated in the catalyst filling device is periodically sampled, and the PCB concentration in the sampled mixed solution is made by Shimadzu Corporation using DB1 (manufactured by J & W Scientific) as a capillary column. Analysis was performed using a gas chromatography mass spectrometer QP5050AW (“GC-MS”).

  When the PCB concentration in the mixed solution did not become the target of 0.5 ppm or less, the operation of returning the mixed solution into the reaction tank after circulating and circulating the mixed solution through the catalyst filling device was repeated.

  After the completion of the first PCB decomposition test, as a second test of IPA reuse, 1.3 ml of PCB used in the first time and 1.99 g of KOH flakes were added to the treatment solution after the decomposition treatment, and completely the same as the first operation. In the same manner, decomposition treatment was performed until the PCB concentration became 0.5 ppm or less.

  After the second test of IPA reuse, as the third test of IPA reuse, 1.3 ml of PCB used in the first time and 1.99 g of KOH flakes were added, and the PCB was completely treated in the same manner as in the first operation. The decomposition treatment was performed until the concentration became 0.5 ppm or less. Similarly, IPA reuse 4th to 10th tests were performed.

  Table 1 shows the time required for decomposition until the PCB concentration reaches 0.5 ppm or less for each test. As is apparent from the results in Table 1, it was confirmed that IPA can be used repeatedly 10 times as it is.

(Example 2)
Except that 2.6 ml of PCB (mixture of KC-400 / trichlorobenzene) (PCB concentration 2 wt% / IPA), 3.98 g of KOH flakes (1.2 equivalents to chlorine) and 147.4 ml of isopropyl alcohol (IPA) were used. The first PCB decomposition test was carried out in the same manner as in Example 1.

  After the completion of the first PCB decomposition test, as a second test of IPA reuse, 2.6 ml of PCB used in the first time and 3.98 g of KOH flakes were added to the treatment solution after the decomposition treatment, and completely the same as the first operation. In the same manner, the decomposition treatment was performed until the PCB concentration became 0.5 ppm or less.

  After the second test of IPA reuse, as a third test of IPA reuse, 2.6 ml of PCB used in the first time and 3.98 g of KOH flakes were added, and PCB was completely treated in the same manner as in the first operation. The decomposition treatment was performed until the concentration became 0.5 ppm or less. In the same manner, the third test of IPA reuse was conducted.

  Table 1 shows the time required for decomposition until the PCB concentration reaches 0.5 ppm or less for each test. As is apparent from the results in Table 1, it was confirmed that IPA could be used repeatedly four times as it was, and the time required for decomposition was also completed within 15 hours.

(Example 3)
Except for using 3.9 ml of PCB (mixture of KC-400 / trichlorobenzene) (PCB concentration 3 wt% / IPA), 5.98 g of KOH flakes (1.2 equivalents to chlorine), and 146.1 ml of isopropyl alcohol (IPA). The first PCB decomposition test was carried out in the same manner as in Example 1.

  After the completion of the first PCB decomposition test, as a second test of IPA reuse, 3.9 ml of PCB used in the first time and 5.98 g of KOH flakes were added to the treated solution after the decomposition treatment, and completely the same as the first operation. In the same manner, decomposition treatment was performed until the PCB concentration became 0.5 ppm or less.

  Table 1 shows the time required for decomposition until the PCB concentration reaches 0.5 ppm or less for each test. As is clear from the results in Table 1, it was confirmed that IPA can be used twice as it is.

  As described above, in the decomposition method according to the present invention, the PCB decomposition processing efficiency can be improved by setting the PCB concentration in the decomposition test to the optimum concentration. In the above example, since the reaction solution can be used at least 10 times with a PCB concentration of 1%, 10/6 times the amount of PCB with the same solvent amount is used compared with the case where the reaction solution is used twice with a PCB concentration of 3%. It can be decomposed.

  Therefore, by setting the decomposition conditions according to the type of the organic chlorine compound, setting the most economical PCB concentration, and repeatedly using the reaction solution, the decomposition method can be economical.

  The decomposition method according to the present invention can be used for decomposition treatment of hardly decomposable organic chlorine compounds such as polychlorinated biphenyls (PCBs), as well as aromatic chlorine compounds such as trichlorobenzene and dichlorobenzene, and fats such as dichloroethane. It can also be used for the decomposition treatment of group chlorine compounds and dioxins.

It is a figure explaining the high concentration PCB decomposition | disassembly method based on this invention. It is a schematic flowchart of the high concentration PCB decomposition | disassembly method based on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Mixed solution 20 Reaction tank 21 Circulation pump 22,23 Piping 30 Microwave apparatus 35 Catalyst filling apparatus

Claims (8)

An organic chlorine compound containing 50% by mass or more of a polychlorinated biphenyl, a hydrogen donating solvent, an alkali compound, packed in a column with at least one catalyst selected from a carbon crystal compound and a compound having a metal supported on a carrier The reaction solution containing 0.2 to 5 wt% (to hydrogen donating solvent) of the organochlorine compound is dechlorinated while circulating the reaction solution through the column packed with the catalyst. , the solution after dechlorination, alkali compound 0.8 to 1.5 equivalents to new organic chlorine compounds 0.2～5Wt% (vs. hydrogen donor solvent) and organic chlorine compounds (to chlorine) A method for decomposing a high-concentration organochlorine compound, characterized in that dechlorination is performed while reusing the reaction solution.   The method for decomposing a high-concentration organochlorine compound according to claim 1, wherein the reaction solution is reused at least twice.   The method for decomposing a high-concentration organochlorine compound according to claim 1 or 2, wherein the catalyst is exchanged at a frequency of 0 to every time the reaction solution is reused. The method for decomposing a high-concentration organochlorine compound according to any one of claims 1 to 3 , wherein microwaves are irradiated to the reaction solution in the catalyst packed column when decomposing the organochlorine compound. The method for decomposing a high-concentration organochlorine compound according to any one of claims 1 to 4 , wherein the reaction solution is continuously passed through a catalyst packed column. The method for decomposing a high-concentration organochlorine compound according to any one of claims 1 to 5 , wherein the alkali compound is NaOH or KOH. The method for decomposing a high-concentration organochlorine compound according to any one of claims 1 to 6 , wherein the catalyst is a palladium-supported carbon compound. The method for decomposing a high-concentration organochlorine compound according to any one of claims 1 to 7 , wherein the hydrogen-donating solvent is isopropyl alcohol.

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