JP4889557B2 - Method and apparatus for cleaning PCB contaminated transformer - Google Patents

Description

The present invention relates to a cleaning method and a cleaning device for a PCB-contaminated transformer that cleans a transformer using oil containing polychlorinated biphenyl (PCB), and more particularly, from a transformer in which oil containing PCB is enclosed to PCB contamination. By removing the oil and injecting oil that does not contain PCB or whose polychlorinated biphenyl content is within the regulation (standard) range and circulate or leave it, it will adhere to the inner wall and internal members of the transformer. The present invention relates to a cleaning method and a cleaning apparatus for a PCB-contaminated transformer that cleans a permeated PCB.

  After a small amount of PCB was detected from insulating oil (which does not use PCB) in heavy electrical equipment such as transformers, the country established the “Low Concentration PCB Contamination Countermeasures Review Committee” in 2003. We are conducting a full-scale study to solve the problem of PCB contamination. The amount of PCB-mixed devices is as low as ppm order, the target devices are many, and the users are in many industries including SMEs. In addition, a rational processing method is required.

  As a method of detoxifying transformers already contaminated with PCB, by injecting and circulating insulating oil (new oil) that does not contain PCB into a transformer in which insulating oil containing PCB is sealed In addition, it is disclosed that cleaning is performed (for example, Patent Documents 1 to 13), and further, cleaning is performed by setting new oil to 100 ° C. or higher (see Patent Document 14).

  However, the methods described in Patent Documents 1 to 13 cannot efficiently detoxify transformers contaminated with PCB, and the method described in Patent Document 14 has a high cleaning action. However, there is a risk of ignition due to sparks caused by friction in the transformer.

Japanese Patent Laid-Open No. 2005-203534 JP 2005-203523 A JP-A-2005-204907 JP 2005-224252 A JP 2005-177435 A JP 2005-223002 A JP 2005-253878 A JP 2005-276965 A JP 2005-276964 A JP 2005-277321 A JP 2005-294371 A JP 2006-122767 A JP 2006-80433 A Japanese Patent Laid-Open No. 2002-92088

This invention is made | formed in view of this present condition, and makes it a subject to solve the said various problems in the past and to achieve the following objectives. That is, the present invention provides a cleaning method and a cleaning apparatus for a PCB-contaminated transformer that can efficiently clean a transformer contaminated with PCB and can suppress ignition during the cleaning. Objective.

  In order to solve the above-mentioned problems, the present inventors have conducted intensive studies. As a result, when the temperature of the oil is 30 to 40 ° C. and the PCB-contaminated transformer is circulated and washed, the PCB-contaminated transformer is removed after about 60 hours. Discovered that PCB leaching into circulating oil stops and that the temperature of oil is raised to 90 ° C where there is little risk of ignition, and PCB leaching is promoted to complete the present invention. It came to do.

This invention is based on the said knowledge by this inventor, and as a means for solving the said subject, it is as follows. That is,
<1> PCB contamination in which PCB contaminated transformer contaminated with polychlorinated biphenyl is injected with oil that does not contain polychlorinated biphenyl or the concentration of polychlorinated biphenyl is within the regulation (standard) range. In the method for cleaning a transformer, the method for cleaning a PCB-contaminated transformer is characterized by including a heating step of heating the injected oil so that the temperature of the injected oil is 40 to 90 ° C.
In <1>, since the oil is heated so that the temperature of the injected oil is 40 to 90 ° C., it is possible to efficiently clean the transformer contaminated with PCB and The ignition at the time can be suppressed.
<2> The method for cleaning a PCB-contaminated transformer according to <1>, wherein the oil circulation flow rate is 2.0 to 3.0 (mL / min).
<3> PCB pollution transformers that are contaminated with polychlorinated biphenyls are injected with oil that does not contain polychlorinated biphenyls or whose polychlorinated biphenyl content is within the regulation (standard) range. A method for cleaning a PCB contaminated transformer, comprising a heating step of heating the injected oil so that the temperature of the injected oil is 40 to 90 ° C.
In <3>, since the oil is heated so that the temperature of the injected oil becomes 40 to 90 ° C., the transformer contaminated with PCB can be efficiently cleaned, The ignition at the time can be suppressed.
<4> Replacing the injected oil with the PCB itself, or contaminated oil containing PCB, adhering to or penetrating the inner wall and internal member of the transformer container constituting the transformer by reducing the viscosity of the oil injected by heating The method for cleaning a PCB-contaminated transformer according to any one of <1> to <3>.
<5> The method for cleaning a PCB-contaminated transformer according to any one of <1> to <4>, wherein the temperature rising rate of the oil in the heating step is 6 to 8 (° C./h).
<6> The method for cleaning a PCB-contaminated transformer according to any one of <1> to <5>, further including a temperature adjustment step of adjusting the temperature of the injected oil to 30 to 40 ° C. is there.
<7> The PCB-contaminated transformer according to any one of <1> to <6>, wherein a natural oil, a mineral oil, or a synthetic oil used for fuel oil, lubricating oil, edible oil, or the like is used as the injected oil. This is a cleaning method.
<8> The transformer is a method for cleaning a PCB-contaminated transformer according to any one of <1> to <7>, including a reactor and a capacitor.
<9> An oil containing no polychlorinated biphenyl or having a polychlorinated biphenyl content within the regulation (standard) range is circulated in a PCB-contaminated transformer contaminated with polychlorinated biphenyl, A cleaning apparatus for a PCB contaminated transformer for cleaning a contaminated transformer, comprising: heating means for heating the oil so that the temperature of the oil is 40 to 90 ° C. is there.
<10> The cleaning device for a PCB-contaminated transformer according to <9>, wherein the oil circulation flow rate is 2.0 to 3.0 (mL / min).
<11> An oil containing no polychlorinated biphenyl or having a polychlorinated biphenyl content within a regulation (standard) range is left in a PCB-contaminated transformer contaminated with polychlorinated biphenyl, A cleaning apparatus for a PCB contaminated transformer for cleaning a contaminated transformer, comprising: heating means for heating the oil so that the temperature of the oil is 40 to 90 ° C. is there.
<12> Reduce the viscosity of the oil by heating, and replace the PCB itself that has adhered to or penetrated into the inner wall and internal members of the transformer or the contaminated oil containing the PCB with the oil that has been circulated or left unattended. The apparatus for cleaning a PCB-contaminated transformer according to any one of <9> to <11>.
<13> The apparatus for cleaning a PCB-contaminated transformer according to any one of <9> to <12>, wherein the heating rate of the oil heated by the heating unit is 6 to 8 (° C./h).
<14> The PCB contamination transformer cleaning device according to any one of <9> to <13>, further including a temperature adjusting unit that adjusts the temperature of the oil to be 30 to 40 ° C.
<15> The PCB-contaminated transformer according to any one of <9> to <14>, wherein the circulated or left oil is natural oil, mineral oil, or synthetic oil used for fuel oil, lubricating oil, edible oil, and the like. It is a cleaning device for the vessel.
<16> The transformer is a cleaning device for a PCB-contaminated transformer according to any one of <9> to <15>, including a reactor and a capacitor.

According to the present invention, it is possible to provide a cleaning method and a cleaning apparatus for a PCB-contaminated transformer that can efficiently clean a transformer contaminated with PCB and can suppress ignition during cleaning. .

(Cleaning method for PCB contaminated transformer)
According to the method for cleaning a PCB-contaminated transformer of the present invention, a PCB-contaminated transformer contaminated with polychlorinated biphenyl does not contain polychlorinated biphenyl, or the concentration of polychlorinated biphenyl is within the regulation (standard) range. In a method for cleaning a PCB-contaminated transformer to be cleaned by injecting and circulating or leaving, a heating step of heating the injected oil to a temperature of 40 to 90 ° C. is included. For example, the cleaning method for PCB-contaminated transformers includes a process of removing PCB-contaminated oil from a transformer contaminated with PCB, and the concentration of polychlorinated biphenyl that does not contain PCB or is within the regulation (standard) range. An injection step of injecting the oil into the PCB-contaminated transformer, a heating step of heating the oil so that the temperature of the oil injected into the PCB-contaminated transformer is 40 to 90 ° C., and other steps. . Here, as oil to be injected, for example, natural oil, mineral oil, or synthetic oil used for fuel oil, lubricating oil, edible oil, or the like is used. In addition, the oil whose polychlorinated biphenyl content concentration is within the regulation (standard) range is currently an oil whose polychlorinated biphenyl content concentration is 0.5 ppm (mg / kg) or less (FIG. 17 described later). Show.
In addition, a cleaning device for circulating and cleaning a PCB contaminated transformer and other devices are used as a method for cleaning the PCB contaminated transformer.

<Transformer>
As shown in FIGS. 1 and 2, the transformer 100 mainly includes a lid portion 1, an outer can container 2 welded to the lid portion 1, and an internal member (inside the lid portion 1 and the outer can container 2). Core) 3.
As shown in FIGS. 3 and 4, the core 3 is mainly placed on the iron core 4, an iron core 4 made of laminated iron plates, a coil 5 arranged around the iron core 4, and the iron core 4. A bakelite 6 and an iron frame 7 arranged so as to sandwich the coil 5 are provided. The coil 5 is mainly composed of a copper wire 8 (FIG. 5) wound around the iron core 4. The thin paper 9 (insulating paper) (FIG. 5) wound around the copper wire 8 and copper And cardboard 10 (FIG. 6) provided as a spacer between the lines 8. Moreover, the cloth 11 (FIG. 7) is wound around the connection.

<Washing device>
As shown in FIG. 8, a cleaning device 80 for cleaning the transformer 100 is mainly connected to an oil scattering prevention container 81 in which the transformer 100 is installed and an oil scattering prevention container 81 to prevent oil scattering. A liquid feed pump 82 that feeds oil to the transformer 100 installed in the container 81, and a temperature controller (cooler 83, main heating tank) that is connected to the oil splash prevention 81 and regulates the temperature of the circulating oil to a predetermined temperature. 84, and a preheating heating tank 85).
The cleaning device 80 is further connected to a thermometer 86 that measures the temperature of the circulating oil, an integrated flow meter 87 that measures the flow rate of the circulating oil, and an oil scattering prevention container 81 for safety such as prevention of ignition. A nitrogen gas line 88 that encloses nitrogen in the oil scattering prevention container 81, a pressure gauge 89 that is disposed between the preheating heating tank 85 and the liquid feeding pump 82 and measures the pressure of circulating oil, and a preheating. A sampling line 90 for sampling oil between the heating tank 85 and the pressure gauge 89 is provided. The transformer includes a reactor, a capacitor, and the like.

<Other devices>
The device used for the method of cleaning the PCB contaminated transformer is basically equipped with a device other than the cleaning device 80 if necessary, as long as it has functions of oil injection or replacement, and oil circulation and heating. May be. For example, when injecting oil into the transformer 100, an oil purifier that sufficiently removes dust, moisture, dissolved gas, etc. in the oil by filtration and vacuum degassing (for example, VSD-6000ES- manufactured by Sanmi Tex Co., Ltd.) N type outdoor portable type).

<Oil removal process for PCB contaminated oil>
The welded portion between the lid 1 and the outer can container 2 is cut to open the lid 1, and the core 3 integrated with the lid 1 is removed from the outer can container 2. Next, the PCB-contaminated oil (base oil) in the outer can container 2 is transferred to a metal tank using a pump.
As described above, it is not limited to removing the PCB contaminated oil in the outer can container 2 using a pump. For example, the PCB contaminated oil is removed from the oil vent provided in the lower part of the transformer 100. You may drain oil.

<Oil injection process>
First, the outer can container 2 is installed in the oil scattering prevention container 81, and then the core 3 integrated with the lid portion 1 is installed in the outer can container 2 installed in the oil scattering prevention container 81. After that, the first pipe (suction port) 91 (FIG. 9) is installed so that the outer can container 2 is connected to the liquid feed pump 82, and the second can so that the outer can container is connected to the cooler 83. A pipe (discharge port) 92 (FIG. 9) is installed. Furthermore, a third pipe (discharge port) 93 (FIG. 9) is installed for an abnormal time. After installing these pipes 91-93, the oil spill prevention container 81 is covered and nitrogen gas is sealed in the oil spill prevention container 81, so that the concentration of oil or polychlorinated biphenyl that is not contaminated with PCB is regulated. Oil 45L within the (reference) range is injected from the lower layer of the transformer 100 through the first pipe (suction port) 91 (injection process), and from the upper layer of the transformer 100 through the second pipe (discharge port) 92. The transformer 100 is washed by being circulated or left to be discharged.

<Heating process>
In all periods of the circulation washing, circulation is the feed rate of the oil (circulating flow rate) is 0 to 10.0 m L / min, preferably, such that 2.0 to 3.0 m L / min Set. Further, the oil is heated so that the temperature of the circulated oil is 40 to 90 ° C., preferably 50 to 90 ° C., more preferably 50 to 70 ° C. (heating step), and naturally cooled after the heating.
In addition, the temperature increase rate of the oil in a heating process is set so that it may become 6-8 (degreeC / h), for example.

<Other processes>
As a method for cleaning the PCB-contaminated transformer, steps other than the oil removal step, the injection step, and the heating step may be included as necessary. For example, a temperature adjustment step for adjusting the temperature of the oil to 30 to 40 ° C, or after naturally cooling the oil so that the temperature of the oil becomes 40 to 90 ° C and naturally cooling, the temperature of the oil is again 40 to 90 ° C. In the second heating step for heating the oil so as to become, when the transformer 100 is injected with oil that is not contaminated by PCB, or oil whose polychlorinated biphenyl concentration is within the regulation (standard) range An oil purification process for sufficiently removing dust, moisture, dissolved gas, and the like in oil by filtration and vacuum degassing.
In the present embodiment, the transformer 100 is partially disassembled and installed in the cleaning apparatus 80, and the transformer 100 is cleaned by circulating or leaving the oil. However, the present invention is not limited to this. Alternatively, an oil purifier may be connected to the transformer 100, and the transformer 100 may be cleaned by circulating oil between the transformer 100 and the oil purifier.

  EXAMPLES Examples of the present invention will be described below, but the present invention is not limited to these examples, and includes ordinary alterations and modifications to these performed in the technical field.

Example 1
<Transformer>
Transformers contaminated with PCB are small reactors (type NITX, oil-filled hermetically sealed, oil quantity) stored in Yokosuka area (2-6-1 Nagasaka, Yokosuka City, Kanagawa Prefecture) A 45 L capacity, manufactured by Meidensha Co., Ltd., production year 1964, production number 1T85701) was used.

<Washing device>
As the cleaning device, the cleaning device having the structure shown in FIG. 8 was used.

<Oil removal process for PCB contaminated oil>
If PCB contaminated oil scatters or leaks, place a vinyl sheet so that it does not penetrate the floor, place a small reactor on the bat installed on the vinyl sheet, and cut the weld between the lid and the outer can container. The lid was opened, and the core integrated with the lid was removed from the outer can container. Next, two 20 L metal tanks (organic solvent waste liquid tanks) were prepared, and the PCB-contaminated oil in the outer can container was transferred to the metal tank using a pump. The total PCB concentration of the extracted PCB-contaminated oil (base oil) was 20.7 mg / kg.

<Injection process and heating process>
First, the outer can container of the small reactor was installed in the oil scattering prevention container of the cleaning device, and then the lid and the core of the small reactor were installed in the outer can container installed in the oil scattering prevention container. After that, the first pipe (suction port) was installed so that the outer can container was connected to the liquid feed pump, and the second pipe (discharge port) was installed so that the outer can container was connected to the cooler. . In addition, a third pipe (discharge port) was installed in case of an abnormality. After installing these pipes, 45 L of oil not contaminated with PCB was injected into the small reactor through the first pipe (suction port), and nitrogen gas was sealed in the oil scattering prevention container. In the entire period of the circulating washing were set as feed rate of the oil to be circulated is 2.0 m L / min. Further, the temperature of the circulated oil is adjusted by heating and cooling so that the temperature of the circulated oil becomes 30 to 40 ° C. until 98 hours after the start of the test, and the temperature of the circulated oil is between 98 hours and 105 hours. The temperature was adjusted by heating and cooling so as to be 40-90 ° C. After 105 hours, the temperature control was stopped and natural cooling was performed. Furthermore, temperature control was started so that the temperature of the oil circulated again after 40 hours would be 40 to 90 ° C, temperature control was stopped after 127 hours, and natural cooling was performed until 142 hours later. Over the entire test period, oil circulated from the sampling line of the cleaning device at an arbitrary time was collected and used as an analysis sample. The temperature of the circulated oil was measured with a thermometer installed in a small reactor, and the circulation flow rate was measured with an integrating flow meter installed near the inlet to the transformer.

<PCB concentration analysis>
<< PCB concentration analysis of oil collected from sampling line >>
For PCB analysis of oil, biosensor, gel permeation chromatography / gas chromatography with electron capture detector (GPC / GC / ECD), and high resolution gas chromatograph-high resolution mass spectrometer (HRGC / HRMS) Using.

<<< PCB analysis of oil using biosensor >>>
The following antibody and carrier were used for the PCB concentration analysis of oil using a biosensor, and the following pretreatment was performed on the oil for PCB concentration analysis.

  Monoclonal mouse anti-PCB antibody (manufactured by Sumika Chemical Analysis Co., Ltd.) was used for PCB concentration analysis of oil using a biosensor. As the secondary antibody, a CY-5-labeled monoclonal goat anti-mouse antibody (Jackson ImmunoResearch co.) Was used.

Agarose beads (NHS-activated Sepharose ^™ 4 fast flow, manufactured by Amercham Biosciences) were used as a solid support. The bead carrier was activated according to the following procedure. The suspension is taken to a bead volume of 1 mL and washed 10 times with 1 mL of 1 mM hydrochloric acid (HCl). Furthermore, after washing 10 times with 1 mL of physiological saline (phosphate buffered saline, pH 7,5, hereinafter referred to as “PBS”), the suspension was suspended in 0.9 mL of PBS. Next, 0.1 mL of a PBS solution containing a complex of the synthesized dichlorophenol derivative and bovine serum albumin (hereinafter referred to as “BSA”) at a concentration of 1 mg / mL was added to the suspension. After shaking at room temperature for 2 hours, 0.1 mL of a PBS solution containing BSA at a concentration of 100 mg / mL was added, followed by further shaking for 2 hours. After shaking, the beads were suspended in 30 mL of PBS and filled into a detection cell described later.

  A silica gel multilayer column was used for oil pretreatment. Specifically, it is a two-layer column of silica gel impregnated with fuming sulfuric acid in the upper layer and silica gel not impregnated with fuming sulfuric acid in the lower layer. After 0.5 g of anhydrous sodium sulfate was overlaid on this column, 0.25 g of oil was added, and 0.2 mL of n-hexane was further added to allow the oil to penetrate into the column. After being allowed to stand for 5 minutes to promote decomposition of the oil component, 15 mL of n-hexane was added, and the whole amount was recovered in an eggplant type flask. 0.25 mL of dimethyl sulfoxide (DMSO) was added, and n-hexane was removed with a rotary evaporator in a 40 ° C. hot water bath. Thereafter, the remaining solution was transferred to a microtube and centrifuged (10,000 rpm, 1 minute), and 0.15 mL of a DMSO layer was taken as a pretreatment solution.

The PCB concentration was measured with a detection cell using a Kinexa 3000 apparatus (manufactured by Sapidyne Instruments Inc.). The hollow cell is filled with a bead carrier. The oil pretreatment liquid prepared by the above procedure is mixed with an antibody (primary antibody: mouse anti-PCB monoclonal antibody, secondary antibody: Cy-5 labeling). Goat anti-mouse antibody) is added to the cell. In the antibody mixed solution, the primary antibody is present as a label to which the secondary antibody is bound. When the oil contains PCB, the primary antibody binds to the PCB in the extract to form an antibody-PCB conjugate and therefore passes through the detection cell. On the other hand, when PCB does not contain in oil, since a primary antibody couple | bonds with the dichlorophenol derivative in a detection cell, an antibody is capture | acquired in a cell. By examining the amount of captured antibody, it is possible to know the presence or absence of PCB in the oil. The amount of antibody captured in the cell can be optically measured as fluorescence (excitation wavelength: 620 nm, measurement wavelength: 670 nm) from the dye on the secondary antibody. The detection cell is irradiated with excitation light, and the resulting fluorescence is measured as an electrical signal by a photodiode. The higher the PCB concentration in oil, the smaller the signal value, and the PCB concentration in oil can be measured from the decrease.
The antibody solution to be used in the apparatus was prepared by the following procedure. The primary antibody and the secondary antibody were both diluted with PBS containing 0.1% (w / w) BSA (hereinafter referred to as “PBS-BSA”). The concentrations of the primary antibody and the secondary antibody were 500 pM and 2 nM, respectively. On the other hand, various oils (new oil, new oil to which Kanechlor was added and new oil used for washing) were prepared in accordance with the above-mentioned operation, and pretreatment liquids were prepared and diluted 50 times with PBS-BSA. An assay solution was prepared by mixing an equal amount of the antibody solution and a diluted solution of the pretreatment solution. At this time, the DMSO concentration in the measurement solution was set to 2% (v / v). The prepared measurement solution was subjected to an automatic apparatus. Conversion from the measured signal value to the PCB concentration was performed using a calibration curve measured by pretreatment of fresh oil to which an equal mass mixture of Kanechlor 300, 400 and 500 was added.

<<< PCB concentration analysis of oil using GPC / GC / ECD >>>
The oil to be subjected to PCB concentration analysis of oil using GPC / GC / ECD was subjected to the following pretreatment.

  After injecting 20 mL of n-hexane and 10 mL of concentrated sulfuric acid into a 50 mL flask, 1 g of a sample was added. After slowly stirring for 2 hours to decompose organic matter, the hexane layer was separated, washed 3 times with 10 mL of purified water, and dehydrated with sodium sulfate (anhydrous). Next, the hexane layer was concentrated to 0.5 mL or less, and made up to 10 mL with a GPC eluent (ethyl acetate: cyclohexane = 3: 7) to prepare a pretreatment solution.

  Fractionation was performed by injecting 2 mL of the pretreatment liquid into the GPC apparatus with a syringe. About 30 mL of the eluate (18 to 25 minutes) was collected as a PCB fraction, concentrated and then made up to 1 mL with the GPC eluent and subjected to GC / ECD analysis. The GPC fractionation conditions are shown below. For GC / ECD analysis, an InnerCap-1 column (length 30 m, membrane pressure 1.5 μm, inner diameter 0.53 mm) was used.

-GPC fractionation conditions-
Precolumn: CLNpak EV-G, 20φ × 100mm
Preparative column: CLNpak EV-2000, 20φ × 300mm
Eluent: Ethyl acetate: Cyclohexane = 3: 7
Elution rate: 4.2 mL / min

FIG. 14 is a graph showing changes in PCB concentration in oil during circulation cleaning. In addition, the inside of the dotted line frame in FIG. 14 shows the period which heated oil.
The oil was collected over time from the start of oil circulation cleaning, and the total PCB concentration in the oil was determined by a biosensor and GPC / GC / ECD for the collected sample. From the measurement results of the biosensor, the total PCB concentration in oil was about 0.2 mg-PCB / kg-Oil 20 hours after the start of the circulation cleaning. Thereafter, the total PCB concentration in the oil became almost constant after 60 hours. Therefore, as a result of heating and circulating cleaning in the period from 98 hours to 105 hours, a sudden increase in total PCB concentration in oil was observed during the heating period. However, when the circulation cleaning was performed by heating again during the period from 119 hours to 127 hours, no increase in the total PCB concentration in the oil was observed. The GPC / GC / ECD measurement results performed as confirmation of the total PCB concentration in the oil also showed the same tendency as the biosensor measurement results.
FIG. 15 is a graph showing the change with time of the oil temperature during the circulation cleaning, and FIG. 16 is a graph showing the change with time of the oil flow rate during the circulation cleaning. In addition, the inside of the dotted line frame in FIG.15 and FIG.16 shows the period which heated oil.
As shown in FIG. 15 and FIG. 16, it was confirmed that the oil flow rate was constant in the range of around 2.0 mL / min throughout the period of the circulation cleaning, and only the temperature was changed as the circulation condition.
From the above results, under the conditions of this experiment (circulation flow rate of 2.0 mL / min), when circulating cleaning was performed at an oil temperature of 30 to 40 ° C., PCB leaching from the reactor to the circulating oil after about 60 hours To stop. Moreover, it turned out that the leaching of PCB is accelerated | stimulated by heating up oil temperature to 90 degreeC. Furthermore, this promoting effect was obtained within a heating time of about 7 hours, and it was suggested that extending the heating time further does not contribute to PCB leaching.
The promotion of PCB leaching due to an increase in oil temperature is considered to be due to an increase in the oil exchange rate on the surface of the member to be cleaned due to a decrease in oil viscosity. That is, the effect is achieved by the principle of encouraging replacement of the circulating oil with heating by reducing the viscosity of the circulating oil and the PCB itself adhering to or penetrating the inner wall and internal members of the transformer, or contaminated oil containing PCB. It is a cleaning method to obtain.

<<< High-resolution gas chromatograph-PCB concentration analysis of oil using high-resolution mass spectrometer >>>
The PCB concentration analysis in oil (base oil) in Table 1 described later is the “Test method for standards pertaining to specially managed general waste and specially controlled industrial waste” (Ministry of Health, Welfare Notification No. 192), Schedule 2 ( This was performed according to the method for analyzing PCBs in waste oil) (FIG. 10). In addition, the apparatus used for the measurement is a high resolution gas chromatograph-high resolution mass spectrometer (HRGC: HP6890N, manufactured by Agilent, HRMS: AutoSpec NTS, manufactured by Micromass).

<< Collecting transformer parts before cleaning >>
The lid and core of the small reactor were lifted and removed from the outer can container, and left as it was for several hours. After leaving, a part of the core was cut with an electric saw. The cut members were divided into materials and used as PCB concentration analysis samples. Specifically, thin paper (insulating paper wound around the copper wire) and copper wire (metal copper with the thin paper removed) were collected from the core copper wire coil. Cardboard used as a spacer between the coils was also collected. At this time, a sample for PCB concentration analysis was also collected from the inner wall of the outer can container in accordance with the second (wiping test method) (Table 11) of the third table.

<< Collecting transformer parts after cleaning >>
After removing the connecting piping between the small reactor and the cleaning device, the lid, the core, and the outer can container were removed from the oil scattering prevention container of the cleaning device. Then, it was left for several hours. After leaving, the core was taken out and partly cut with an electric saw. The cut members were divided into materials as described above and used as PCB concentration analysis samples. In addition, a sample for PCB concentration analysis was also collected from the inner wall of the outer can container in accordance with the second (wiping test method) (Table 11) of Appendix 3.
Further, the core was completely disassembled, and the iron plates laminated as the iron core in the center were collected, and the second (wiping test method) of Appendix Table 3 was performed (FIG. 11). Similarly, the iron plate laminated | stacked as an iron frame was separated, and the sample for PCB density | concentration analysis was extract | collected according to the 2nd (wiping test method) of the attached table 3 (FIG. 11). Further, a sample for PCB concentration analysis was also collected from bakelite according to the second (wiping test method) of Appendix Table 3 (FIG. 11).
<< PCB concentration analysis of transformer members >>
PCB concentration analysis of transformer members is pre-processed according to the method described in the standard verification method for specially managed general waste and specially controlled industrial waste (Ministry of Health and Welfare Notification No. 192). The analysis was performed using a measuring apparatus.
The PCB adhering to the outer can container was pretreated according to the second (wiping test method) (Fig. 11) of Appendix 3, and the PCB was quantified by low resolution mass spectrometry (LRGC / LRMS). Copper wires and papers (thick paper and thin paper) collected from the coil are pretreated according to the third (Fig. 13) and fourth (Fig. 12) of Appendix Table 3, respectively, and the PCB is quantified with a low-resolution mass meter. Went.
On the other hand, the iron core, the iron frame, and the bakelite were pretreated in accordance with the second (wiping test method) of Appendix Table 3 (FIG. 11).

  The PCB concentration remaining on the inner wall and inner member of the outer can container before and after circulation cleaning was measured. The results are shown in Table 1. The analysis was performed by the pretreatment method described, and a low-resolution mass spectrometer was used for all measurements.

The PCB adhering to the inner wall of the outer can container was subjected to pretreatment according to the second (wiping test) (Fig. 11) of Appendix Table 3 and analyzed. In the wiping test, the metal surface is wiped off with absorbent cotton containing an organic solvent, so that the PCB attached to the inner wall surface of the outer can container can be recovered together with the oil component. Before the circulation cleaning, the amount of PCB adhered was 0.34 μg-PCB / 100 cm ² -surface area, but after the circulation cleaning, it became 0.007 μg-PCB / 100 cm ² -surface area, and a remarkable cleaning effect was recognized. . Since the judgment standard (FIG. 17) of the wiping test in the PCB detoxification treatment is 0.1 μg-PCB / 100 cm ² -the surface area or less, the judgment criterion of the wiping test is at least due to the circulation of the oil (FIG. 17). It was thought that PCB could be removed by washing to a concentration satisfying the above. In addition, secondary contamination due to washing was not observed.

  PCB attached to the copper wire sampled from the coil was analyzed by pretreatment according to the third (member sampling test) of the third table (FIG. 13). In the member sampling test, since the member is washed with an organic solvent in which PCB easily dissolves, PCB attached to the surface or inside of the member can also be recovered. However, the amount of PCB adhered before and after the circulation cleaning was less than 0.01 mg-PCB / kg-member. The criterion (FIG. 17) of the member sampling test in the PCB detoxification process is 0.01 mg-PCB / kg-member or less. Therefore, with respect to the copper wire collected from the coil, no PCB adhesion exceeding at least the judgment standard of the member sampling test (FIG. 17) was observed before and after the circulation cleaning. In addition, secondary contamination due to washing was not observed.

  The PCB contained in the thin paper wound around the copper wire coil and the cardboard used as the gap material of the copper wire coil was subjected to pretreatment according to Attached Table 4 (FIG. 12) and analyzed. Attached Table No. 4 (FIG. 12) is a pretreatment method for the purpose of estimating the dissolution of PCB from a member into water. As a result, no elution of PCB from the thin paper and the thick paper collected from the coil before and after the circulation cleaning to the water was observed, and the PCB concentration was less than 0.003 mg-PCB / L-test solution. The criterion for waste paper in the PCB detoxification process (FIG. 17) is 0.003 mg-PCB / L-test solution or less. From this, with respect to paper, before and after the circulation cleaning, at least elution of PCB in the test solution exceeding the fourth criterion (FIG. 17) was not recognized. In addition, secondary contamination due to washing was not observed.

  As mentioned above, the removal effect of PCB by circulation washing became clear about copper wire and paper (thick paper and thin paper) collected from an outer can container and a coil. Therefore, for the purpose of confirming the cleaning effect, the PCB concentration was also measured for the iron core, iron frame, and bakelite after circulation cleaning. As a sample, a core of a small reactor was disassembled, and an iron plate stacked as an iron core at the center of the core was collected. Similarly, iron plates stacked as iron frames were also arranged. Furthermore, bakelite, which was a component of an iron core, was also collected as a sample for PCB concentration analysis. As described above, the collected analysis samples were analyzed by the described pretreatment method and analyzed by gas chromatography with electron capture detection. The results are shown in Table 1.

The PCB attached to the iron core and the iron frame was analyzed by pretreatment according to the second (wiping test) of the third table (FIG. 11). As a result, the iron core and the iron frame after the circulation cleaning were less than 0.1 μg-PCB / 100 cm ² -surface area. The criterion for the wiping test in the PCB detoxification treatment (FIG. 17) is 0.1 μg-PCB / 100 cm ² -surface area or less. From this, with respect to the iron core and the iron frame, the PCB could be washed and removed to a concentration satisfying at least the criteria for the wiping test (FIG. 17) by circulating the oil.

The PCB adhering to the bakelite was subjected to pretreatment according to the second (wiping test) of the third table (FIG. 11) and analyzed. As a result, the PCB adhesion amount was less than 0.1 μg-PCB / 100 cm ² -surface area. Therefore, the amount of PCB adhering to the bakelite after the circulation cleaning satisfied 0.1 μg-PCB / 100 cm ² -surface area or less, which is a judgment standard (FIG. 17) of the wiping test in the PCB detoxification process.

  From the above results, the PCB contaminated oil (total PCB concentration 20.7 mg / kg) was extracted from the small reactor, and the oil not containing PCB was injected into the small reactor and circulated and washed. When circulating cleaning is performed, the leaching of PCB from the small reactor to the circulating oil should stop after about 60 hours. Moreover, it turned out that the leaching of PCB is accelerated | stimulated by heating up oil temperature to 90 degreeC.

  In addition, with the above-described circulation cleaning, for the outer can container of the small reactor, the PCB can be cleaned and removed to a concentration that satisfies the second criterion (wiping test) of the third table (wiping test) in the PCB detoxification process (FIG. 17). it was thought. In addition, for copper wire sampled from a coil that is a member constituting a core of a small reactor, the third (member sampling test) judgment standard (FIG. 17) in the third table of the PCB detoxification process is performed before and after circulation cleaning. Excess PCB adhesion was not observed. Regarding the papers collected from the coil, the PCB elution into the test solution exceeding the fourth criterion (Figure 17) in the PCB detoxification treatment was not observed before and after the circulation cleaning.

  In addition, with regard to the iron core and iron frame constituting the core of the small reactor, after circulation cleaning, PCB adhesion exceeding the second (wiping test) judgment standard (Fig. 17) in the third table of PCB detoxification treatment Was not recognized. Similarly, with regard to bakelite, no adhesion of PCB exceeding the second (wiping test) judgment standard (FIG. 17) in the third table was observed after circulation cleaning.

(Principle confirmation test)
In this research, insulating oil contaminated with PCB was removed from the transformer filled with insulating oil, and new oil not contaminated with PCB was injected and circulated to adhere to and penetrate the inner wall and internal members of the transformer. It became clear that the PCB could be washed. At this time, it was confirmed that a high PCB cleaning effect can be obtained by heating the new oil to be circulated. However, the scientific basis is unknown. Therefore, in this section, we focused on the decrease in the circulating oil viscosity accompanying the increase in the oil temperature, and examined the relationship between the decrease in the circulating oil viscosity and the cleaning effect.

<Member>
For the principle confirmation test, papers collected from a transformer (100 kVA) were used. The collected paper sample was cut into a square of about 5 mm and used for the experiment.

<Analysis of PCB in oil>
The total PCB concentration in the oil was measured by PCB concentration analysis of the oil using the biosensor described above.

<Viscosity measurement>
For the viscosity measurement, an SV-10 viscometer manufactured by AND was used. First, a hot water bath incubator capable of temperature control from 30 ° C. to 90 ° C. was prepared. The viscosity measurement container was immersed in an incubator set at 30 ° C., and 40 mL of an oil sample was placed therein. Furthermore, the measurement was started after the measurement part was immersed in the sample and the temperature of the sample reached 30 ° C. The temperature was raised to 90 ° C. over time, and the viscosity measurement was continued during that time. The oil samples used as samples were silicone oil (KF-96L-2C, KF-96-10CS, and KF-96-100CS, all manufactured by Shin-Etsu Chemical Co., Ltd.), insulating oil (electric insulating oil type 1 No. 2, Matsumura Oil Co., Ltd.), vegetable oil (salad oil) (commercial product, Ajinomoto Co., Inc.), and kerosene.

<Dissolution test>
50 mL of each of the above oils was placed in a 100 mL Erlenmeyer flask and stored in an incubator capable of temperature control from 30 ° C to 70 ° C. When the set incubator temperature and oil temperature became constant, 10 g of the paper sample was added and the test was started. During the test time, 1 mL of an oil sample was collected over time while stirring the flask as needed. These collected samples were subjected to a biosensor to determine the total PCB concentration in oil.

<Test results>
-Elution promotion effect by heating-
In the transformer, elution of PCB from the member was promoted by heating the circulating oil to 70 ° C. or 90 ° C., and an increase in PCB concentration in the circulating oil was observed. A similar phenomenon was confirmed from this experiment. That is, when PCB-contaminated paper was immersed in insulating oil and PCB elution was observed by measuring the PCB concentration in the oil, when elution (immersion) was started at an oil temperature of 30 ° C., about 7 hours. The elution rate decreased (total PCB concentration in oil became almost constant). However, when heating up to 90 ° C. was started after 9 hours, an increase in PCB concentration in oil showing promotion of PCB elution was observed (FIG. 18A). Therefore, when an elution test was performed at an oil temperature of 70 ° C., high PCB elution acceleration was shown from an increase in the PCB concentration in the oil (FIG. 18B). From the above results, it was predicted that the PCB acceleration effect by heating was caused by the oil phase exchange due to the decrease in viscosity. In fact, when the viscosity of the insulating oil was measured at each oil temperature, it was found that the temperature decreased from 8.8 mPa · s to 2.9 mPa · s with a temperature increase from 30 ° C. to 70 ° C. (FIGS. 19A and B).
Next, in order to ascertain whether the PCB elution promoting effect is caused by special components in the insulating oil, the PCB promoting effect is obtained by the viscosity change due to heating using a vegetable (salad) oil having a significantly different compound structure of the oil component. It was confirmed whether it was seen or not. When the PCB elution concentration was measured over time after heating to 30 ° C., 45 ° C. and 70 ° C., the elution amount increased in descending order of temperature (FIG. 20). The viscosity of the vegetable oil is 40.3 mPa · s at 30 ° C., 23.3 mPa · s at 45 ° C., and 11.4 mPa · s at 70 ° C. (FIGS. 19A and B). Therefore, it was considered that the PCB elution promoting effect was obtained by lowering the viscosity of the washing oil rather than the special chemical component in the insulating oil.
If a PCB promoting effect can be obtained by lowering the viscosity, an oil having an originally different viscosity under the same temperature condition should have the same effect without heating. Therefore, a PCB elution test from PCB-contaminated paper was performed using silicone oil, which is a synthetic oil, at an oil temperature of 70 ° C. (FIG. 21). The reason why the silicone oil was selected is that oils having different viscosities can be obtained first, and secondly, the same accelerating effect can be confirmed even with synthetic oils having a composition different from that of the insulating oil. As a result, it was found that the PCB elution effect increased in order of increasing viscosity. The viscosity of the silicone oil at 70 ° C. is shown in FIGS. The viscosity of each silicone oil at 70 ° C. is 0.9 mPa · s for A, 3.8 mPa · s for B, and 39.3 mPa · s for C. As described above, the PCB elution was different due to the difference in the viscosity of the oil under the same temperature condition. From this, the effect of promoting the elution from the PCB contaminated member of the transformer to the insulating oil obtained by heating involves the activation of at least the exchange of the contaminated oil and the cleaning oil in the member due to the decrease in the viscosity of the oil. It became clear. This effect was supported by the fact that a linear relationship was established between the insulating oil viscosity and the PCB elution concentration when the viscosity of the insulating oil or vegetable oil was changed by heating. Furthermore, when silicone oils having different viscosities at the same temperature were used as the cleaning oil, a linear relationship was observed between the oil viscosity and the PCB elution concentration, confirming the previous action.
On the other hand, if the PCB elution amount is governed only by the immersion oil viscosity, the PCB elution effect is the same regardless of the oil type if the cleaning oil has the same viscosity. However, in the insulating oil, vegetable oil, and silicone oil, there was a difference in the slope and position of the linear relationship established between the viscosity and the PCB elution concentration (FIG. 22). These results indicate that the PCB elution effect is caused by the activation of oil phase exchange due to a decrease in viscosity, but the degree of activation is considered to be affected by the ease of mixing the contaminated oil in the member with the cleaning oil. It was.
Then, the elution test was done at 30 degreeC using the kerosene which is easy to mix with insulating oil. Kerosene has a lower viscosity than insulating oil and is 0.83 mPa · s at 30 ° C. (FIGS. 19A and B). Therefore, a high elution effect can be expected with kerosene having a low viscosity and easy to mix with insulating oil. In fact, a total PCB concentration in oil approximately twice that of insulating oil was observed at the same immersion time at 30 ° C. (FIG. 23). .

  The method for cleaning a PCB-contaminated transformer of the present invention is a small transformer of less than 0.5t (for example, a transformer installed on a power pole) or a medium-sized transformer of 0.5t or more but less than 30t (for example, installed in a substation) Can be suitably used for PCB cleaning of large transformers (for example, transformers installed in power plants) of 30 tons or more.

FIG. 1 is a diagram showing an external appearance of a transformer in which the method for cleaning a PCB-contaminated transformer of the present invention is implemented. FIG. 2 is a view showing an appearance of an internal member (core) of the transformer of FIG. FIG. 3 is a view showing the structure of the internal member in FIG. FIG. 4 is a diagram showing a further internal structure of the internal member in FIG. FIG. 5 is a diagram showing copper wire and thin paper collected from the coil in FIG. FIG. 6 is a view showing cardboard provided as a spacer between the copper wires of the coil in FIG. 3. FIG. 7 is a diagram illustrating the cloth wound around the connection. FIG. 8 is a diagram showing a system of a cleaning device used in the method for cleaning a PCB contaminated transformer of the present invention. FIG. 9 is a diagram showing piping connecting the transformer of FIG. 1 and the cleaning device of FIG. FIG. 10 is a diagram showing “Approach Method for Standards Related to Specially Managed General Waste and Specially Managed Industrial Waste” (Ministry of Health and Welfare Notification No. 192), Appendix 2 (PCB Analysis Method in Waste Oil). FIG. 11 is a diagram showing the second (wiping test method) of Appendix Table 3 “Standard Test Method for Specially Managed General Waste and Specially Controlled Industrial Waste” (Ministry of Health and Welfare Notification No. 192 in 1992). FIG. 12 is a diagram showing Attached Table No. 4 (eluate test method) of “standard verification method for specially managed general waste and specially controlled industrial waste” (Ministry of Health and Welfare Notification No. 192, 1992). FIG. 13 is a diagram showing the third (part sampling test method) of the attached table 3 of “Certification method for standards concerning specially managed general waste and specially controlled industrial waste” (Ministry of Health and Welfare Notification No. 192 of 1992). . FIG. 14 is a graph showing changes in PCB concentration in oil during circulation cleaning. FIG. 15 is a graph showing the change over time in the temperature of the oil during circulation cleaning. FIG. 16 is a graph showing the change with time of the circulation rate of oil during circulation cleaning. Fig. 17 shows the criteria for PCB treatment (Waste Treatment Law Enforcement Ordinance Article 2-4, Paragraph 1, Item 5) and the verification method (Waste Treatment Law Enforcement Regulation, Article 1-2, Paragraph 4). FIG. FIG. 18A is a diagram showing a PCB elution effect by insulating oil heating. FIG. 18B is another diagram showing the PCB elution effect by insulating oil heating. FIG. 19A is a diagram showing the relationship between oil temperature and viscosity. FIG. 19B is an enlarged view of FIG. 19A. FIG. 20 is a diagram showing the PCB elution effect by heating vegetable oil. FIG. 21 is a diagram showing the PCB elution effect of silicone oils having different viscosities. FIG. 22 is a diagram showing the relationship between the viscosity and PCB elution effect in various oils. FIG. 23 is a diagram showing the relationship between the immersion time in various oils and the PCB elution effect.

Explanation of symbols

1 Lid 2 Outer can 3 Internal member (core)
4 Iron core 5 Coil 6 Bakelite 7 Iron frame 8 Copper wire 9 Thin paper 10 Thick paper 11 Cloth 80 Cleaning device 81 Oil scattering prevention container 82 Liquid feed pump 83 Cooler 84 Main heating tank 85 Preheating heating tank 86 Thermometer 87 Integrated flow meter 88 Nitrogen gas line 89 Pressure gauge 90 Sampling line 91 First pipe (suction port)
92 Second piping (discharge port)
93 3rd piping (discharge port)
100 transformer

Claims (18)

PCB contaminated transformer that does not contain polychlorinated biphenyl in the PCB contaminated transformer contaminated with polychlorinated biphenyl or circulates and cleans by injecting oil whose polychlorinated biphenyl content is within the regulation (standard) range In the cleaning method,
Look including a heating step where the temperature of the injected oil heats the oil so that the 40 to 90 ° C.,
Transformer members after cleaning are judged according to the second (wiping test) in Appendix 3 of the “Examination Method for Standards Related to Specially Managed General Waste and Specially Controlled Industrial Waste” (Ministry of Health and Welfare Notification No. 192) A method for cleaning a PCB-contaminated transformer, characterized by satisfying both the third (member sampling test) judgment standard of the Attached Table 3 and the fourth judgment standard of the Attached Table 4 . A temperature adjustment step for adjusting the temperature of the injected oil so that the temperature of the injected oil is 20 to 40 ° C .;
The method for cleaning a PCB-contaminated transformer according to claim 1, further comprising a heating step of heating the oil so that a temperature of the temperature-controlled oil becomes 50 to 90 ° C. The method for cleaning a PCB-contaminated transformer according to any one of claims 1 to 2, wherein the circulating flow rate of oil is 2.0 to 3.0 (mL / min). PCB contaminated transformer contaminated with polychlorinated biphenyl is injected with oil that does not contain polychlorinated biphenyl or the concentration of polychlorinated biphenyl is within the regulation (standard) range, and the PCB contaminated transformer is left to wash In the method
A heating step of heating the oil so that the temperature of the injected oil is 40 to 90 ° C.,
Transformer members after cleaning are judged according to the second (wiping test) in Appendix 3 of the “Examination Method for Standards Related to Specially Managed General Waste and Specially Controlled Industrial Waste” (Ministry of Health and Welfare Notification No. 192) A method for cleaning a PCB-contaminated transformer, characterized by satisfying both the third (member sampling test) judgment standard of the Attached Table 3 and the fourth judgment standard of the Attached Table 4. A temperature adjustment step for adjusting the temperature of the injected oil so that the temperature of the injected oil is 20 to 40 ° C .;
The method for cleaning a PCB-contaminated transformer according to claim 4, further comprising: a heating step of heating the oil so that a temperature of the temperature-controlled oil becomes 50 to 90 ° C. Claims that reduce the viscosity of the oil injected by heating and promote the exchange of the injected oil with the PCB itself, or contaminated oil containing PCB, that adheres or penetrates into the inner wall and internal members of the transformer container constituting the transformer. Item 6. A method for cleaning a PCB-contaminated transformer according to any one of Items 1 to 5. The method for cleaning a PCB-contaminated transformer according to any one of claims 1 to 6, wherein the temperature rising rate of the oil in the heating step is 6 to 8 (° C / h). The method for cleaning a PCB-contaminated transformer according to any one of claims 1 to 7, wherein natural oil, mineral oil, or synthetic oil used for fuel oil, lubricating oil, edible oil, or the like is used as the injected oil. The method for cleaning a PCB-contaminated transformer according to any one of claims 1 to 8, wherein the transformer includes a reactor and a capacitor. An oil that does not contain polychlorinated biphenyl or whose polychlorinated biphenyl content is within the regulatory (standard) range is circulated in a PCB contaminated transformer contaminated with polychlorinated biphenyl, and the PCB contaminated transformer In the cleaning equipment for PCB contaminated transformer,
A heating means for heating the oil so that the temperature of the oil is 40 to 90 ° C;
Transformer members after cleaning are judged according to the second (wiping test) in Appendix 3 of the “Examination Method for Standards Related to Specially Managed General Waste and Specially Controlled Industrial Waste” (Ministry of Health and Welfare Notification No. 192) A cleaning device for a PCB-contaminated transformer, characterized by satisfying both the third (member sampling test) judgment standard of the third table and the fourth judgment standard of the second table. Temperature control means for controlling the temperature of the injected oil so that the temperature of the injected oil is 20 to 40 ° C .;
The cleaning device for a PCB-contaminated transformer according to claim 10, further comprising a heating unit that heats the temperature-controlled oil so that the temperature of the oil becomes 50 to 90 ° C. The apparatus for cleaning a PCB-contaminated transformer according to any one of claims 10 to 11, wherein an oil circulation flow rate is 2.0 to 3.0 (mL / min). Oil which does not contain polychlorinated biphenyl or whose polychlorinated biphenyl content is within the regulation (standard) range is left in a PCB-contaminated transformer contaminated with polychlorinated biphenyl, and the PCB-contaminated transformer In the cleaning equipment for PCB contaminated transformer,
A heating means for heating the oil so that the temperature of the oil is 40 to 90 ° C;
Transformer members after cleaning are judged according to the second (wiping test) in Appendix 3 of the “Examination Method for Standards Related to Specially Managed General Waste and Specially Controlled Industrial Waste” (Ministry of Health and Welfare Notification No. 192) A cleaning device for a PCB-contaminated transformer, characterized by satisfying both the third (member sampling test) judgment standard of the third table and the fourth judgment standard of the second table. Temperature control means for controlling the temperature of the injected oil so that the temperature of the injected oil is 20 to 40 ° C .;
The cleaning device for a PCB-contaminated transformer according to claim 13, further comprising a heating unit that heats the temperature-controlled oil so that the temperature of the oil becomes 50 to 90 ° C. Claims in which the viscosity of oil is reduced by heating, and the exchange of the circulated or left oil with PCB itself adhering to or penetrating the inner wall of the transformer container and the internal member constituting the transformer or the contaminated oil containing PCB is promoted. The cleaning device for a PCB-contaminated transformer according to any one of 10 to 14. The apparatus for cleaning a PCB-contaminated transformer according to any one of claims 10 to 15, wherein the temperature rising rate of the oil heated by the heating means is 6 to 8 (° C / h). The apparatus for cleaning a PCB-contaminated transformer according to any one of claims 10 to 16, wherein the circulated or left oil is natural oil, mineral oil, or synthetic oil used for fuel oil, lubricating oil, edible oil or the like. The cleaning device for a PCB-contaminated transformer according to any one of claims 10 to 17, wherein the transformer includes a reactor and a capacitor.