JP5436889B2 - 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. Oil was extracted, and oil that did not contain PCB or that contained PCB in the regulation (standard) range was injected or circulated or left to adhere to or penetrate into the inner wall or internal member of the transformer. The present invention relates to a cleaning method and a cleaning apparatus for a PCB-contaminated transformer that cleans PCBs.

  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.

  Currently, the national government has proposed incineration of contaminated oil, and in a demonstration test, it has been confirmed that when insulating oil containing PCB is incinerated in an incinerator, the production of dioxins and the like is less than the environmental concentration. However, in order to solve the trace PCB problem, an inexpensive and safe treatment method for equipment such as a transformer is indispensable together with the realization of incineration treatment of contaminated oil.

  In the United States, replacement of insulating oil is being studied as an inexpensive treatment method for equipment. A process of extracting the insulating oil from the PCB-contaminated transformer and re-injecting the insulating oil was proposed in 2001 after a test by the Ministry of Environmental Protection. However, this is merely a replacement and does not exhibit the PCB elution effect. On the other hand, in Japan, there is no detailed examination example about the process of replacing the insulating oil of the PCB contaminated transformer. One reason for this is that the actual PCB contamination standard value in Japan is 0.5 mg / kg in oil, the lowest in the world. That is, in addition to the replacement, a method for effectively washing out the PCB inside the transformer in the insulating oil is necessary.

  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 , Cleaning is disclosed (for example, Patent Documents 1 to 13).

  However, the methods described in Patent Literatures 1 to 13 cannot efficiently detoxify transformers and the like contaminated with PCB.

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

  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, an object of the present invention is to provide a cleaning method and a cleaning apparatus for a PCB-contaminated transformer that can efficiently clean a transformer contaminated with PCB.

Means for solving the problems are as follows. That is,
<1> An oil extraction step of extracting oil from a PCB-contaminated transformer contaminated with polychlorinated biphenyl, an injection step of injecting oil substantially not containing polychlorinated biphenyl into the PCB-contaminated transformer, A method for cleaning a PCB-contaminated transformer, comprising a step of applying power to the PCB-contaminated transformer.
In <1>, since the PCB-contaminated transformer is charged, the transformer contaminated with PCB can be efficiently cleaned.
<2> PCB contamination by performing at least one of external heating, external cooling, heat retention, strength of applied voltage, intensity of applied voltage, intermittent application of electricity, and natural cooling in the electricity application process. The method for cleaning a PCB-contaminated transformer according to <1>, wherein the temperature of oil in the transformer is changed.
<3> The method for cleaning a PCB-contaminated transformer according to any one of <1> to <2>, including an oil removal step, an injection step, and a power application step in an arbitrary order.
<4> The method for cleaning a PCB-contaminated transformer according to any one of <1> to <3>, further including another oil extraction step of extracting the injected oil from the PCB-contaminated transformer after the power application step. It is.
<5> The voltage applied to the PCB-contaminated transformer in the power application process is the return load method in the transformer temperature test method, the equivalent load method in the transformer temperature test method, the actual load method in the transformer temperature test method, The method for cleaning a PCB-contaminated transformer according to any one of <1> to <4>, wherein the method is performed using any one of connections to a power system.
<6> The method for cleaning a PCB-contaminated transformer according to any one of <1> to <5>, wherein the temperature of the oil is within a range of room temperature to 100 ° C.
<7> The method for cleaning a PCB-contaminated transformer according to <6>, wherein the temperature of the oil is within a range of 30 ° C to 80 ° C.
<8> Pollution contaminated with polychlorinated biphenyl itself or polychlorinated biphenyl adhering to or penetrating the inner wall and internal members of the transformer container constituting the transformer, reducing the viscosity of the injected oil by increasing the temperature of the oil The method for cleaning a PCB-contaminated transformer according to any one of <1> to <7>, wherein an exchange between oil and injected oil is promoted.
<9> The oil according to any one of <1> to <8>, wherein the oil to be injected is natural oil used for fuel oil, lubricating oil, edible oil, mineral oil including electrical insulating oil, or synthetic oil. This is a method for cleaning a PCB contaminated transformer.
<10> The PCB-contaminated transformer according to <9>, wherein the injected oil is any one of waste oil, recycled oil, oil obtained by decomposing PCB by chemical treatment, and oil obtained by removing PCB by physical treatment. This is a cleaning method.
<11> The method for cleaning a PCB-contaminated transformer according to any one of <1> to <10>, wherein the PCB concentration of the injected oil is 0.5 ppm (mg / kg) or less.
<12> An apparatus for cleaning a PCB-contaminated transformer, characterized by comprising a power-applying means for applying power to a PCB-contaminated transformer contaminated with polychlorinated biphenyl.
<13> The electric charging means is a PCB contamination by performing at least one of external heating, external cooling, heat retention, strength of the applied voltage, strength of the applied current, intermittent application of electricity, and natural cooling. The apparatus for cleaning a PCB-contaminated transformer according to <12>, wherein the temperature of oil in the transformer is changed.
<14> The voltage applied to the PCB-contaminated transformer by the means of applying electricity is the return load method in the transformer temperature test method, the equivalent load method in the transformer temperature test method, the actual load method in the transformer temperature test method, The PCB contamination transformer cleaning device according to any one of <12> to <13>, wherein the cleaning device is any one of connection to the power system.
<15> The cleaning device for a PCB-contaminated transformer according to any one of <13> to <14>, wherein the temperature of the oil is within a range of room temperature to 100 ° C.
<16> The apparatus for cleaning a PCB-contaminated transformer according to <15>, wherein the temperature of the oil is within a range of 30 ° C to 80 ° C.
<17> Polychlorinated biphenyl itself or polychlorinated biphenyl adhering to or penetrating the inner wall and internal members of the transformer container constituting the transformer, by reducing the viscosity of the oil injected into the PCB-contaminated transformer due to the increase in oil temperature The cleaning device for a PCB contaminated transformer according to any one of <13> to <16>, wherein the contaminated oil contaminated in step 1 is urged to be replaced with oil injected into the PCB contaminated transformer.
<18> The PCB contamination according to <17>, wherein the oil injected into the PCB-contaminated transformer is a natural oil used for fuel oil, lubricating oil, edible oil, mineral oil containing electrical insulating oil, or synthetic oil. This is a transformer cleaning device.
<19> The above <18>, wherein the oil injected into the PCB-contaminated transformer is any one of waste oil, recycled oil, oil obtained by decomposing PCB by chemical treatment, and oil obtained by removing PCB by physical treatment. This is a cleaning device for PCB contaminated transformers.
<20> The PCB contamination transformer cleaning device according to any one of <17> to <19>, wherein the PCB concentration of oil injected into the PCB contamination transformer is 0.5 ppm (mg / kg) or less. .

  ADVANTAGE OF THE INVENTION According to this invention, the washing | cleaning method and washing | cleaning apparatus of a PCB pollution transformer which can wash | clean the transformer contaminated with PCB efficiently can be provided.

FIG. 1: A is a figure which shows the structure of the internal member in a PCB pollution transformer (the 1). FIG. 1B is a diagram showing a structure of internal members in the PCB contaminated transformer (part 2). FIG. 1C is a diagram showing a structure of internal members in the PCB contaminated transformer (No. 3). FIG. 1D is a diagram showing the structure of internal members of the PCB-contaminated transformer (No. 4). FIG. 1E is a diagram showing the structure of internal members of the PCB-contaminated transformer (No. 5). FIG. 1F is a diagram showing the structure of internal members of the PCB-contaminated transformer (No. 6). FIG. 1G is a diagram showing the structure of internal members of the PCB-contaminated transformer (No. 7). FIG. 2A is a diagram illustrating a structure of a shell type core in the transformer of FIGS. 1A and 1C (part 1). FIG. 2B is a diagram showing a structure of an outer iron core in the transformer of FIGS. 1A and 1C (part 2). FIG. 2C is a diagram showing the structure of the copper coil in FIGS. 2A and 2B (part 1). FIG. 2D is a diagram showing the structure of the copper coil in FIGS. 2A and 2B (part 2). FIG. 3A is a diagram showing a structure of an inner iron core in the transformer of FIGS. 1B and 1D to 1G (No. 1). FIG. 3B is a diagram showing a structure of the inner iron core in the transformer of FIGS. 1B and 1D to 1G (part 2). FIG. 3C is a diagram showing the structure of the copper coil in FIGS. 3A and 3B (part 1). FIG. 3D is a diagram showing the structure of the copper coil in FIGS. 3A and 3B (part 2). FIG. 4 is a diagram illustrating the return load method. FIG. 5 is a diagram showing an equivalent load method. FIG. 6 is a diagram illustrating the actual load method. FIG. 7 is a diagram showing the operation of the electrical charging cleaning test. FIG. 8 is a diagram showing a test circuit based on the return load method. 9A shows the oil temperature and current during the charging period of the transformer of FIG. 1A when the transformer of FIG. 1A and the transformer of FIG. 1C are connected to the test circuit based on the return load method (FIG. 8). It is a graph which shows a voltage change. 9B shows the oil temperature and current during the charging period of the transformer of FIG. 1C when the transformer of FIG. 1A and the transformer of FIG. 1C are connected to the test circuit based on the return load method (FIG. 8). It is a graph which shows a voltage change. 10A shows the oil temperature and current during the charging period of the transformer of FIG. 1B when the transformer of FIG. 1B and the transformer of FIG. 1E are connected to a test circuit based on the return load method (FIG. 8). It is a graph which shows a voltage change. FIG. 10B shows the charging of the transformer of FIG. 1E when the transformer of FIG. 1B (transformer of FIG. 1D) and the transformer of FIG. 1E are connected to a test circuit based on the return load method (FIG. 8). It is a graph which shows the oil temperature, electric current, and voltage change during a period. 10C shows the oil temperature and current during the charging period of the transformer of FIG. 1D when the transformer of FIG. 1D and the transformer of FIG. 1E are connected to a test circuit based on the return load method (FIG. 8). It is a graph which shows a voltage change. FIG. 11A shows the oil temperature, current, and current during the charging period of the transformer of FIG. 1F when the transformer of FIG. 1F and the transformer of FIG. 1G are connected to a test circuit based on the return load method (FIG. 8). It is a graph which shows a voltage change. FIG. 11B shows the oil temperature and current during the charging period of the transformer of FIG. 1G when the transformer of FIG. 1F and the transformer of FIG. 1G are connected to the test circuit based on the return load method (FIG. 8). It is a graph which shows a voltage change. FIG. 12 is a diagram showing members taken from the transformer used in the power application test. FIG. 13 is a diagram showing the second (wiping test method) of Appendix Table 3 “Standard verification method for specially managed municipal waste and specially controlled industrial waste” (Ministry of Health and Welfare Notification No. 192). FIG. 14 is a diagram showing the third (part sampling test method) in the third table of the “Examination Method for Standards Concerning Special Management General Waste and Special Management Industrial Waste” (Ministry of Health and Welfare Notification No. 192 of 1992) . FIG. 15 is a diagram showing “Appendix 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). FIG. 16 is a graph showing changes in PCB concentration in oil of the transformer of FIG. 1A. FIG. 17 is a graph showing changes in PCB concentration in oil of the transformer of FIG. 1B. FIG. 18 is a graph showing changes in PCB concentration in oil of the transformer of FIG. 1C. FIG. 19 is a graph showing changes in PCB concentration in oil of the transformer of FIG. 1D. 20 is a graph showing changes in PCB concentration in oil of the transformer of FIG. 1E. FIG. 21 is a graph showing changes in PCB concentration in oil of the transformer of FIG. 1F. FIG. 22 is a graph showing changes in PCB concentration in oil of the transformer of FIG. 1G. Fig. 23 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 Regulations, Article 1-2, Paragraph 4). FIG.

(PCB contaminated transformer cleaning method, PCB contaminated transformer cleaning device)
Hereinafter, a cleaning method and a cleaning apparatus for a PCB-contaminated transformer according to the present invention will be described.
The method for cleaning a PCB-contaminated transformer of the present invention includes an oil removal step, an injection step, a power application step, and other steps.
In the method for cleaning a PCB-contaminated transformer of the present invention, the oil removal step, the injection step, and the power application step may be performed in any order.
The apparatus for cleaning a PCB-contaminated transformer according to the present invention includes a power applying unit, and further includes other units as necessary.

<Transformer>
The transformer mainly includes an outer can container and an internal member (core) housed in the outer can container.
As shown in FIGS. 1A to 1G, the core is roughly classified into an outer iron type (FIGS. 1A and 1C) and an inner iron type (FIGS. 1B and 1D to 1G).

  As shown in FIGS. 2A and 2B, the outer iron type core includes one iron core 42 and two copper coils 41. Here, the iron core 42 is a wound iron core wound with a thin silicon steel plate, and the inner side of the copper coil 41 is a secondary copper wire 41a (and paper) as shown in FIGS. The outside of the coil 41 was a primary copper wire 41b (and paper).

  The outer iron core is composed of two iron cores 42 and one copper coil 41 as shown in FIGS. 3A and 3B. Here, the iron core 42 is a wound iron core wound with a thin silicon steel plate, and the outer and inner sides of the copper coil 41 are secondary copper wires 41a (and papers) as shown in FIGS. 3C and 3D. The central part of the coil was a primary copper wire 41b (and paper).

<Oil removal process>
The oil removal step is a step of removing oil from the PCB contaminated transformer.
Specifically, first, the outer can container and the core are separated. Next, the PCB-contaminated oil (base oil) in the outer can container is transferred to a metal tank using a pump.
Note that, as described above, it is not limited to removing the PCB contaminated oil in the outer can container using a pump. For example, the PCB contaminated oil is extracted from the oil vent provided in the lower part of the transformer. May be.

<Injection process>
The injection step is a step of injecting into the PCB-contaminated transformer an oil that does not substantially contain polychlorinated biphenyl (an oil whose polychlorinated biphenyl content is within the regulation (standard) range).
Specifically, first, the core is installed in the outer can container. Thereafter, oil substantially free of polychlorinated biphenyl is injected into the transformer.
Here, as oil to be injected, for example, natural oil used for fuel oil, lubricating oil, edible oil, mineral oil including electrical insulating oil, or synthetic oil is used. Note that oil that does not substantially contain polychlorinated biphenyl (oil whose polychlorinated biphenyl content is within the regulatory (standard) range) is currently 0.5 ppm (polychlorinated biphenyl content concentration) mg / kg) or less oil (see FIG. 23).
The oil to be injected may be waste oil, reclaimed oil, oil obtained by decomposing PCB by chemical treatment, and oil obtained by removing PCB by physical treatment. Alternatively, a solvent that can be energized may be used.

<Electricity process (means)>
The power application step (means) is a step (means) of applying power to the PCB contaminated transformer. In the electric power application process, the inside of the PCB contaminated transformer is caused to generate heat, and the temperature of the oil in the PCB contaminated transformer is changed by heating. The temperature of the oil is within the range of room temperature to 100 ° C, and preferably within the range of 30 ° C to 80 ° C. In addition, the temperature increase rate of the oil in the electricity application process is set to be, for example, 1 to 7 (° C./h). Thus, by controlling the temperature of the oil, ignition during cleaning can be suppressed.
In addition to changing the temperature of the oil in the PCB-contaminated transformer by heating due to the power application in the power-applying process, secondary oil circulation in the PCB-contaminated transformer due to heating, vibration of the member due to electromagnetic induction, etc. The effect is also expected.
In addition, the application of power to the PCB-contaminated transformer in the power application process verifies that the temperature rise in each part of the equipment is within a certain limit determined by the type of insulation when the transformer is operated at a rated load. A transformer temperature test method used for the purpose (for example, any one of a return load method, an equivalent load method, and an actual load method) or a connection to an electric system.

<< Return load law >>
For example, as shown in FIG. 4, the return load method corresponds to an actual load by connecting two transformers of the same rating to a pair, and only supplying power for the loss without connecting the load. It is a method that can reproduce voltage and current. In this return load method, a rated load current can be passed at a high voltage, and the amount of electricity used and waste heat are small, and a test with a plurality of units is possible. The numbers in FIG. 4 indicate the order in which the rated load current flows.

<< Equivalent load method >>
The equivalent load method is a method in which one of transformer windings is short-circuited, a load loss corresponding to the total loss is supplied to increase the transformer oil temperature, and then the oil temperature is increased through a rated current. . For example, as shown in FIG. 5, by applying a low voltage (for example, 100V to 200V) to the primary side and short-circuiting the secondary side, a current flows through the transformer at a low voltage. In this case, the power source capacity is small and not a high voltage, so that the test can be easily performed.

<< Actual load method >>
The actual load method is a method in which an actual load is applied for testing. For example, as shown in FIG. 6, a rated current flows through the transformer by allowing a current to flow at a high voltage (eg, 6,000 V) on the primary side and consuming on the secondary side.

<< Connection to electrical system >>
The connection to the electric system is a method in which a transformer is connected to the actual electric system and the current value and the oil temperature are not artificially controlled.

<Other processes>
As a method for cleaning the PCB-contaminated transformer, steps other than the oil removal step, the injection step, and the power application step may be included as necessary. For example, after the electric power application process, when other oil extraction processes are performed to remove the injected oil from the PCB-contaminated transformer, or when oil that does not substantially contain polychlorinated biphenyl is injected, An oil purification step for sufficiently removing dissolved gas and the like by filtration and vacuum degassing. In addition, in the oil removal process, oil draining is performed by external heating or heat retention, in the power application process, external heating, external cooling, heat retention, strength of the applied voltage, strength of the applied voltage, intermittent implementation of the applied power, and It is also possible to perform at least one of natural cooling.

  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
In Example 1, as shown in FIG. 7, the operation of the electrical charging washing test ((1) base oil removal (oil removal process), (2) washing oil (new oil) injection (injection process), (3) Electricity washing based on the return load method (electricity application process), (4) Observation of PCB concentration change over time during electric electricity washing (electricity application process), (5) Collection of copper coil and iron core (material collection), (6) Wipe of the inner wall of the container (collection of members)) was performed. Hereinafter, the operation of the electrical charging cleaning test will be described in detail.

<Transformer>
As a transformer contaminated with PCB, a pole transformer transferred from TEPCO was used (Table 1, FIGS. 1A to 1G). The pole transformers of FIGS. 1A-1E were 10 kVA, and the pole transformers of FIGS. 1F-1G were 30 kVA.

<Oil removal process>
When PCB contaminated oil was scattered or leaked, a transformer was placed on the oil barrier so that it did not penetrate the floor surface, and the core was removed from the outer can container. Next, a drum for waste oil was prepared, and the PCB-contaminated oil in the outer can was transferred to the drum using a pump.
The PCB concentration of PCB contaminated oil (base oil) in the pole transformers of FIGS. 1A to 1E is 2.6 mg-PCB / kg-oil, 24 mg-PCB / kg-oil, and 25 mg-PCB / kg- in order. Oil, 32 mg-PCB / kg-oil, 33 mg-PCB / kg-oil, and the PCB concentration of PCB-contaminated oil (base oil) in the pole transformers of FIGS. 1F to 1G was 54 mg-PCB / kg-oil, 84 mg-PCB / kg-oil.

<Injection process>
First, the core is installed in the outer can container. After that, new oil (electric insulation oil type 1 No. 2, Matsumura Oil) was injected into the transformer, and the oiled transformer was covered. Here, the amount of the injected new oil was the oil amount (L) in Table 1.

<Power transmission process>
Two transformers injected with new oil are connected to a test circuit based on the return load method (Fig. 8), and voltage is applied at the rated voltage and current of the transformer ("Rated (kVA)" in Table 1). went. The charging time was 12 hours per day, and the charging (12 hours) was repeated during the charging period. In addition, the time zone when no power was applied was left connected to the circuit. The voltage and current at the time of power application were recorded by an automatic measuring device, and the temperature of the insulating oil was measured by a thermometer installed inside the transformer.
In addition, the PCB concentration in the insulating oil was measured with a biosensor, which will be described later, by collecting the insulating oil over time ((4) Observation of change in PCB concentration over time during electrical cleaning). In addition, when the replacement of the new oil (oil removal process and injection process) is performed twice, after the transformer is once disconnected from the circuit, the above replacement operation is performed, and the transformer is connected to the circuit again to apply power. Went.
The transformer, which had finished applying electricity, was separated from the circuit, separated from the core and container, and left overnight for oiling.
In addition, the number of days of repeating the charging (12 hours) was defined as the charging period.

9A shows the oil temperature and current during the charging period of the transformer of FIG. 1A when the transformer of FIG. 1A and the transformer of FIG. 1C are connected to the test circuit based on the return load method (FIG. 8). 9B is a graph showing changes in oil temperature, current, and voltage during the voltage application period of the transformer of FIG. 1C.
The voltage was applied at the rated voltage and current of the transformer (“rated (kVA)” in Table 1). The charging time was 12 hours per day, and the charging (12 hours) was repeated over 8 days. In the two transformers, it was confirmed that the temperature at the end of charging every day was 65 ° C. on average and at least within the range of 55 ° C. to 75 ° C. Moreover, it was confirmed that the oil temperature change is in the range of 30 ° C to 80 ° C. It was also confirmed that there was no extreme difference in oil temperature change over time between the two transformers. Furthermore, it was also observed that a current of about 40 A was steadily applied at a voltage of about 200 V in both transformers during the entire charging period.

  Also, the transformer of FIG. 1B and the transformer of FIG. 1E are connected to the test circuit (FIG. 8), and the power is applied for 20 days with the rated voltage and current of the transformer (“rated (kVA)” in Table 1). went. As a result, as shown in FIG. 10A and FIG. 10B, the temperature at the end of the daily power application is about 70 ° C. in the two transformers, and there is no extreme difference in the temperature change over time. It was done. In addition, it was also reproduced that power is constantly supplied with a constant voltage and current. Next, the transformer of FIG. 1D is connected to the test circuit (FIG. 8) instead of the transformer of FIG. 1B, and the transformer of FIG. 1D and the transformer of FIG. 1E are connected to the test circuit (FIG. 8). Then, we applied electricity for 15 days. As a result, as shown in FIG. 10B and FIG. 10C, even when the transformer is replaced, the temperature at the end of the power application every day is about 70 ° C., and it is energized with a constant voltage and current. It was reproduced. It was also confirmed that the oil temperature change was in the range of 30 ° C to 80 ° C.

  Furthermore, the transformer of FIG. 1F and the transformer of FIG. 1G are connected to a test circuit (FIG. 8), and electricity is applied for 28 days at the rated voltage and current of the transformer (“rated (kVA)” in Table 1). It was. As a result, as shown in FIG. 11A and FIG. 11B, the current was supplied with a constant voltage and current, but a slight variation in the oil temperature was also observed. However, it was confirmed that the temperature at the end of the daily charging was at least in the range of 60 ° C to 70 ° C. It was also confirmed that the oil temperature change was in the range of 30 ° C to 80 ° C.

<Parts collection>
After the application process, members were collected according to the following procedure (FIG. 12).
Copper coils were cut from the core and collected. Papers such as adhesive paper and insulating paper, and primary and secondary copper wires were collected from the cut copper coil. The collection was carried out on average so that the parts (periphery, center, upper part or lower part) were not biased.
On the other hand, for the iron core, the core was disassembled and the iron core was taken out.
Regarding the inner wall of the container, the second (wiping test method) of the attached table 3 described in the standard verification method for specially managed municipal waste and specified managed industrial waste (Ministry of Health and Welfare Notification No. 192) (Fig. 13) A sample for analysis was taken according to Also, the locations to be wiped out were not duplicated.

<Parts analysis>
For the analysis of the collected materials, pretreatment and measurement were performed according to the method described in the standard verification method for specially controlled general waste and specified controlled industrial waste (Ministry of Health and Welfare Notification No. 192). The PCB adhering to the inner wall of the container and the iron core was pretreated according to the second (wiping test method) of Appendix Table 3. In the wiping test, the metal surface is wiped off with absorbent cotton containing an organic solvent, so that the PCB attached to the surface of the wall surface can be recovered together with the oil component. The primary and secondary copper wires were subjected to pretreatment according to the third (member sampling test method) in the third table (FIG. 14) after removing deposits such as insulating paper. In the member sampling test, since the member is washed with hexane in which PCB is easily dissolved, the PCB adhering to the member surface can be collected. In addition, the papers were pretreated according to Attached Table 4 (Cleaning Liquid Test Method) (FIG. 15). Attached Table No. 4 is a pretreatment method for the purpose of estimating the dissolution of PCB from a member into water. These pretreated samples were all subjected to PCB quantification by gas chromatography with an electron capture detector (GC / ECD).

<PCB concentration analysis>
<< PCB concentration analysis of oil collected from sampling line >>
Biosensor and gel permeation chromatography / gas chromatography with electron capture detector (GPC / GC / ECD) were used for the analysis of oil PCB concentration.

<<< 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.

  A silica gel multilayer column (manufactured by Sumika Chemical Analysis Co., Ltd.) 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 insulating oil was added, and 0.2 mL of n-hexane was additionally added to allow the insulating oil to penetrate into the column. After leaving for 5 minutes to promote decomposition of the insulating oil component, 15 mL of n-hexane was added, and the entire 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.

For the measurement, a detection cell equipped with a membrane-type carrier was used using a biosensor portable measuring machine (manufactured by Sumitomo Analysis Center). This measuring device is a device capable of measuring absorbance by obtaining power from an internal battery. The size is about 15 cm × 10 cm. The measured value is displayed on a liquid crystal display, stored in an internal memory, and stored in an external PC. Output is possible.
First, a pretreatment solution of insulating oil was added to the antibody solution to promote the binding between PCB and antibody. The ratio of antibody to PCB binding in the liquid depends on the PCB concentration since the antibody concentration is constant. Therefore, if the concentration of antibody not bound to PCB can be measured, the PCB concentration can be calculated. Therefore, the binding equilibrium solution was sent to the measurement cell, and the antibody not bound to PCB was captured using the binding with the pseudoantigen on the carrier. Thereafter, the amount of antibody captured was measured as an optical signal (voltage) optically from the absorption of the colloidal gold with a detection cell attached to a portable measuring machine. Since the electrical signal is correlated with the amount of antibody captured, the PCB concentration was finally determined from the electrical signal.
The antibody was used after diluting to 500 pM with physiological saline (hereinafter abbreviated as PBS-BSA) containing 1% (w / w) bovine serum albumin. On the other hand, 50 μL of the pretreatment solution prepared according to the above method was added to 5 mL of the antibody solution, stirred, and allowed to stand for 30 minutes to prepare a measurement solution. During the standing time, the detection cell was installed in a portable measuring machine and the voltage value of the control was read. Thereafter, 4 mL of the measurement liquid was fed to the same detection cell at a flow rate of 8.5 mL / min, and then 1 mL of PBS-BSA was fed at a flow rate of 8.5 mL / min to wash the measurement cell. The measurement cell was centrifuged at 7,000 rpm for 5 minutes, drained, air-dried for 30 minutes, and again subjected to a portable measuring machine to read the voltage value. The PCB concentration was measured from the calibration value indicated by the PCB concentration corresponding to the voltage value separately prepared by the following procedure from the control and the voltage value after liquid feeding. The detection cell was disposable for each measurement. In addition, when creating a calibration curve, a sample for calibration in which an equivalent mixture of Kanechlor (KC) (KC-300, KC-400, and KC-500) is added to unused insulating oil that does not contain PCB Was measured by the above procedure.

<<< PCB concentration analysis of oil using gel permeation chromatography / gas chromatography with electron capture detector (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 an insulating oil 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.

  Gel permeation chromatography is a method of separating substances having different molecular weights using silica gel particles or the like. Here, a sample is introduced into a column packed with silica gel particles, and the two are separated using a difference in molecular weight between oil component molecules and PCB molecules. Specifically, a predetermined amount of the decomposition-treated sample was injected into a GPC apparatus and eluted with an oil component, and then a fraction containing PCB was collected. The GPC fractionation conditions are shown below. Moreover, the quantification method of PCB by the gas chromatography (GC / ECD) with an electron capture type detector followed JISK-0093.

-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

<Elution of PCB by electricity>
The time-dependent change of PCB elution from the inside of the transformer to the insulating oil during the charging period was examined. Insulating oil was collected every day when the power application operation was completed, and the total PCB concentration in the insulating oil was obtained with a biosensor capable of rapid measurement, and the measurement result was used as a guideline for the next day's electric power operation. . In addition, the same insulating oil was subjected to GPC / GC / ECD to determine the total PCB concentration.

  FIG. 16 shows the PCB concentration in oil during the charging period of the transformer of FIG. 1A when the transformer of FIG. 1A and the transformer of FIG. 1C are connected to the test circuit based on the return load method (FIG. 8). FIG. 18 is a graph showing changes in PCB concentration in oil during the power application period of the transformer of FIG. 1C.

  As shown in FIG. 16, in the transformer of FIG. 1A (base oil PCB concentration 2.6 mg-PCB / kg-oil), the total amount in oil by the biosensor and GPC / GC / ECD during the entire 8-day electricity application period. The PCB concentration was less than 0.3 mg-PCB / kg-oil. On the other hand, as shown in FIG. 18, in the transformer of FIG. 1C (main oil PCB concentration 25 mg-PCB / kg-oil), elution of PCB from the inside of the transformer to the insulating oil was observed with the passage of the electric power application period, The total PCB concentration in oil by biosensor and GPC / GC / ECD reached 1.1 mg-PCB / kg-oil.

  FIG. 17 shows the PCB concentration in oil during the charging period of the transformer of FIG. 1B when the transformer of FIG. 1B and the transformer of FIG. 1E are connected to a test circuit based on the return load method (FIG. 8). FIG. 19 is a graph showing a change, and FIG. 19 is a graph showing the voltage applied to the transformer of FIG. 1D when the transformer of FIG. 1D and the transformer of FIG. 1E are connected to a test circuit based on the return load method (FIG. 8). FIG. 20 is a graph showing changes in PCB concentration in oil during the period, and FIG. 20 is a diagram in which the transformer of FIG. 1B (FIG. 1D) and the transformer of FIG. 1E are connected to a test circuit (FIG. 8) based on the return load method. It is a graph which shows the PCB density | concentration change in oil in the case of the voltage application period of the transformer of FIG.

  In addition, FIG.17, FIG.19 and FIG.20 is the result obtained by the following operation. Connect the transformer of FIG. 1B and the transformer of FIG. 1E to the test circuit based on the return load method (FIG. 8), and after 7 days of powering operation, change the oil again and perform the powering operation. Furthermore, it was observed whether PCB re-elution was observed by continuing (electricity application period 20 days). Then, the transformer of FIG. 1B and the transformer of FIG. 1D were replaced.

As shown in FIG. 17, in the transformer of FIG. 1B (main oil PCB concentration 24 mg-PCB / kg-oil), the total PCB concentration in oil by the biosensor and GPC / GC / ECD was also applied on the 20th day of the electricity application period. Was less than 0.3 mg-PCB / kg-oil.
As shown in FIG. 19, in the transformer of FIG. 1D (main oil PCB concentration 32 mg-PCB / kg-oil), significant PCB elution was observed at the beginning of the electricity application period, and in the oil on the first day of the electricity application period. The total PCB concentration was 0.6 mg-PCB / kg-oil. Thereafter, gradual elution continued and became constant at a total PCB concentration in oil of 1.0 mg-PCB / kg-oil after the 12th day of the charging period. This tendency was seen in both biosensor and GPC / GC / ECD measurement results.
As shown in FIG. 20, in the transformer of FIG. 1E (main oil PCB concentration 33 mg-PCB / kg-oil), the total PCB concentration in oil is 0.3 to 0.4 mg-PCB / PCB on the 20th day of the electricity application period. kg-oil and PCB elution was observed. However, no increase in PCB concentration was observed even when the charging operation was continued until 35 days.

FIG. 21 shows the PCB concentration in oil during the charging period of the transformer of FIG. 1F when the transformer of FIG. 1F and the transformer of FIG. 1G are connected to the test circuit based on the return load method (FIG. 8). FIG. 22 is a diagram showing a change in PCB concentration in oil during a power application period of the transformer of FIG. 1G.
21 and 22 show the results obtained by the following operation. Connect the transformer of Fig. 1F and the transformer of Fig. 1G to the test circuit based on the return load method (Fig. 8), perform the electricity operation for 14 days, change the oil again, and perform the electricity operation. Furthermore, it was observed whether PCB re-elution was observed by continuing (electric charging period 28 days).

  As shown in FIG. 21, in the transformer of FIG. 1F (main oil PCB concentration 54 mg-PCB / kg-oil), the total PCB concentration in oil by GPC / GC / ECD is 1.0 mg in the 14th charging period. -PCB / kg-oil. After this, when the oil was changed for the second time and the charging operation was continued for 14 days, the total PCB concentration in oil by the biosensor and GPC / GC / ECD was 0.3 mg-PCB / Less than kg-oil.

  As shown in FIG. 22, in FIG. 1G (base oil PCB concentration 84 mg-PCB / kg-oil), the total PCB concentration in oil according to GPC / GC / ECD was 1.3 mg-PCB / PCG in the 14th charging period. After that, when the oil was changed for the second time and the electric charging operation was continued for 14 days, the total PCB concentration in the oil by the biosensor and GPC / GC / ECD was 0.3 mg-PCB / kg-oil. Was less than.

  From the above results, it was found that a period of about 2 weeks was required to elute into the insulating oil after replacing the PCB inside the transformer by applying electricity.

<Effects of PCB cleaning by applying electricity>
The amount of PCB attached to the inner wall of the container and the member after the application of electricity was measured. The measurement results are shown in Table 2.
PCB contamination of transformer inner walls and components has been verified by the standard verification method for specially controlled general waste and specified controlled industrial waste (Ministry of Health and Welfare Notification No. 192 of 1992). This test method is intended for members that have been subjected to chemical PCB detoxification treatment, but was applied as an indicator of the PCB cleaning effect.

When a power application operation for 8 days is performed on the transformer of FIG. 1A (main oil PCB concentration 2.6 mg-PCB / kg-oil), the amount of PCB attached to the primary and secondary copper wires after the power application operation is It was less than 0.01 mg-PCB / kg-member. The inspection standard of the member sampling test in the PCB detoxification treatment was 0.01 mg-PCB / kg-member or less, and no PCB adhesion exceeding the standard was observed on the copper wire. The amount of PCB elution from paper was less than 0.003 mg-PCB / kg-test solution. The paper waste test standard in the PCB detoxification treatment was 0.003 mg-PCB / kg-member or less, and no elution of PCB exceeding the standard was observed from the papers. The amount of PCB attached to the inner wall of the container and the iron core was less than 0.1 μg-PCB / 100 cm ² -surface area. The inspection standard of the member sampling test in the PCB detoxification treatment is 0.1 μg-PCB / 100 cm ² -surface area or less, and no adhesion of PCB exceeding the standard was observed on the inner wall of the container and the iron core.

When the transformer of Fig. 1C (main oil PCB concentration 25mg-PCB / kg-oil) is subjected to a power application operation for 8 days, the amount of PCB attached to the inner wall of the container, the primary and secondary copper wires, and the PCB from paper About the amount of elution, it was below the test standard applicable in a PCB detoxification process. However, the PCB adhesion amount to the iron core was 0.2 μg-PCB / 100 cm ² -surface area, and the PCB adhesion amount exceeding the test standard in PCB detoxification treatment was recognized. The reason why the PCB remained was that the concentration of the base oil PCB was higher than that of the transformer of FIG. 1A during the same power application period, and it took time to clean and remove the PCB. Moreover, in the transformer of FIG. 1C, the PCB concentration in the insulating oil at the end of the charging is 1.1 mg-PCB / kg-oil by biosensor and GPC / GC / ECD, and the insulating oil in the PCB detoxification treatment It exceeded the test standard of 0.5 mg-PCB / kg-oil.

1D transformer power (main oil PCB concentration 32mg-PCB / kg-oil), when 15 days of power application, the amount of PCB attached to the primary and secondary copper wires, and the amount of PCB elution from paper Was less than the relevant test criteria in the PCB detoxification process. However, the amount of PCB attached to the inner wall of the container and the iron core was 0.1 μg-PCB / 100 cm ² -surface area, which is the same as the test standard in the PCB detoxification treatment. Further, in the transformer of FIG. 1D, the PCB concentration in the insulating oil at the end of charging is 1.2 mg-PCB / kg-oil for biosensor, 1.0 mg-PCB / kg-oil for GPC / GC / ECD. Yes, it exceeded 0.5 mg-PCB / kg-oil, which is the test standard for insulating oil in PCB detoxification treatment.

Transformer of FIG. 1B (base oil PCB concentration 24 mg-PCB / kg-oil), transformer of FIG. 1E (base oil PCB concentration 33 mg-PCB / kg-oil), transformer of FIG. 1F (base oil PCB concentration 54 mg- PCB / kg-oil) and the transformer of FIG. 1G (main oil PCB concentration 84 mg-PCB / kg-oil) were subjected to member analysis. As a result, for all the transformers, the amount of PCB attached to the inner wall of the container and the iron core was less than 0.1 μg-PCB / 100 cm ² -surface area. Similarly, the amount of PCB attached to the primary and secondary copper wires was less than 0.01 mg-PCB / kg-member, and the amount of PCB elution from paper was less than 0.003 mg-PCB / kg-test solution. It was. These measurement results were below the test standard in the PCB detoxification treatment of the corresponding member in the PCB adhesion amount and the elution amount. In addition, the PCB concentration in the insulating oil at the end of the charging is also 0.5 mg-PCB, which is the standard for insulating oil in the PCB detoxification process, based on the biosensor and GPC / GC / ECD measurement results in any transformer. / Kg-oil or less.

  Based on the above, it was considered effective to combine a power application period of about two weeks and oil replacement for PCB cleaning of a transformer by power application.

41 Copper coil 41a Secondary copper wire 41b Primary copper wire 42 Iron core

Claims (11)

An oil extraction process for extracting oil from a PCB contaminated transformer contaminated with polychlorinated biphenyl;
Injecting oil into the PCB contaminated transformer substantially free of polychlorinated biphenyl;
In the method for cleaning a PCB contaminated transformer, including a power application step of applying power to the PCB contaminated transformer,
The electric charging step is to replace the oil substantially not containing the polychlorinated biphenyl at a certain point in the entire electric charging period, and the entire electric charging period is not less than 2 weeks and not more than 20 days ,
Transformer member after the electric power transmission process is "the inspection method of the standard concerning special management general waste and special management industrial waste" (Ministry of Health, Welfare Notification No. 192) second of the third table (wiping test) And the third criterion (part sampling test) of the third table, and the fourth criterion of the third table, and the PCB concentration in the oil after the charging process is 0.5 mg / A method for cleaning a PCB-contaminated transformer, characterized in that it is kg or less.   In the electrical charging process, external heating, external cooling, thermal insulation, strength of the applied voltage, strength of the applied current, intermittent implementation of the applied power, and spontaneous cooling are performed in the PCB contaminated transformer. The method for cleaning a PCB-contaminated transformer according to claim 1, wherein the temperature of the oil is changed.   The method for cleaning a PCB-contaminated transformer according to any one of claims 1 to 2, comprising an oil extraction step, an injection step, and a power application step in an arbitrary order.   The method for cleaning a PCB-contaminated transformer according to any one of claims 1 to 3, further comprising another oil extracting step of extracting the injected oil from the PCB-contaminated transformer after the power application step.   Electricity is applied to PCB-contaminated transformers in the electric charging process. Return load method in transformer temperature test method, equivalent load method in transformer temperature test method, actual load method in transformer temperature test method, power system The method for cleaning a PCB-contaminated transformer according to any one of claims 1 to 4, wherein the cleaning method is performed using any one of the connections.   The method for cleaning a PCB-contaminated transformer according to any one of claims 1 to 5, wherein the temperature of the oil is in the range of room temperature to 100 ° C.   The method for cleaning a PCB-contaminated transformer according to claim 6, wherein the temperature of the oil is in the range of 30 ° C to 80 ° C.   Polychlorinated biphenyl itself or contaminated oil contaminated with polychlorinated biphenyl, which decreases the viscosity of the injected oil due to an increase in the temperature of the oil and adheres to or penetrates the inner wall and inner member of the transformer container constituting the transformer; The method for cleaning a PCB-contaminated transformer according to any one of claims 1 to 7, which prompts replacement with injected oil.   The PCB-contaminated transformer according to any one of claims 1 to 8, wherein the oil to be injected is natural oil used for fuel oil, lubricating oil, edible oil, mineral oil containing electrical insulating oil, or synthetic oil. Cleaning method.   The method for cleaning a PCB-contaminated transformer according to claim 9, wherein the injected oil is any one of waste oil, reclaimed oil, oil obtained by decomposing PCB by chemical treatment, and oil obtained by removing PCB by physical treatment.   The method for cleaning a PCB-contaminated transformer according to any one of claims 1 to 10, wherein the PCB concentration of the injected oil is 0.5 ppm (mg / kg) or less.