JPH11309222A - Method for recovering harmful insulating oil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To recover harmful insulating oil by a simple process without omission at a high recovery rate by condensing and recovering the harmful insulating oil in an exhaust system after decompressing and heating electrical appliances within a vacuum heating furnace to carbonize members impregnating the harmful insulating oil and to evaporated the harmful insulating oil. SOLUTION: A condenser 2 including PCB is engaged inserting into a vacuum heating furnace 1, and a vacuum pump 6 is operated to decompress an interior of the furnace 1. When the interior is decompressed to a pressure of 0.01 to 50 mbav, radiation heating is started by a heater 3. This decompressing and heating are continuously conducted carbonize members impregnating harmful insulating oil and to evaporate the harmful insulating oil. An exhaust gas including a vapor of the harmful insulating oil is cooled and condensed by a cooling condenser 4 to be collected in a collecting container 5. The exhaust gas after the recovery is discharged into air through activated charcoal filters 7 and 9. A sensor 8 is provided between the filter 7 and the filter 9 to supervise a value including harmful constituents in the exhaust gas. The exhaust gas can be kept collecting under a measuring marginal value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for recovering harmful insulating oil from electrical equipment using a member impregnated with harmful insulating oil such as PCB.

[0002]

2. Description of the Related Art PCB (polychlorinated biphenyl) has been used in various applications such as electric insulating oil and pressure-sensitive paper due to its stability, heat resistance and insulating properties. It was found that it easily accumulates in living organisms and has chronic toxicity. Production and use were halted, and production and import were also prohibited in principle. However, a stable decomposition method of waste PCB oil has not been established yet, and the same applies to a method of treating containers and PCB contaminants.
For this reason, waste PCB oil and electrical equipment containing the same are currently stored by businesses, etc., except that some PCBs are still used after sealing the PCB.
However, from the point of leakage of PCB to the environment due to accidents and the like due to long-term storage, and increase in storage amount due to the transfer of PCB used equipment that has been used so far,
There is a need for an early establishment of a PCB contaminant treatment method.

[0003] As for a stable decomposition treatment method of waste PCB oil itself, development of chemical treatment methods such as a high-temperature incineration treatment method at 1100 ° C or higher and an alkali catalytic decomposition method (BCD method) have been advanced. It is said that it is sufficiently possible to decompose waste PCB oil to a safe level by treating it based on the above method.

On the other hand, electrical equipment containing PCB oil, waste PC
As for the method of recovering PCB from the container after extracting the B oil and the PCB contaminants to which the PCB adheres, for example, in the case of a transformer, the oil is removed and then the solvent is washed.
A method of removing B, a method of evaporating and recovering PCB by vacuum heating after tilting oil removal, and the like have been considered.
However, electrical devices such as transformers and capacitors use members made of paper or wood impregnated with PCB (hereinafter, sometimes abbreviated as insulating members), and the PCB is recovered from these members. It was difficult.

[0005] With respect to such a point, Japanese Patent Application No. 9-993 has been proposed.
According to No. 41, after the oil was drained from the transformer on the power distribution pole, the above-mentioned insulating member was crushed into small pieces, and the pieces were washed with a solvent under predetermined conditions to remove the PCB, and then the PCB was removed from the solvent. A method of recovering a PCB by separating is disclosed.

[0006] In addition, JP-A-9-192534 and JP-A-9-192535 disclose that after removing oil from a transformer on a power distribution pole, only the aforementioned insulating member is disassembled and cut as necessary. Evaporate PCB by vacuum heating
A method of recovery is disclosed

[0007]

However, in the case of the method of cleaning using a solvent as in the method described in Japanese Patent Application No. 9-99341, the process becomes complicated and the work environment becomes poor.
There are problems such as leakage of CB and the need to take measures against PCB contamination by workers.

Further, even in a method utilizing vacuum heating, Japanese Patent Application Laid-Open Nos. 9-192534 and 9-19925.
In the method described in JP-A No. 35, paper impregnated with PCB
It is necessary to disassemble and cut a member made of wood, and there is a problem such as leakage of PCB in these steps as in the method described in Japanese Patent Application No. 9-99341.

[0009]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, the present invention provides a method of recovering harmful insulating oil from electrical equipment using a member impregnated with harmful insulating oil such as a PCB by a simple process. An object of the present invention is to provide a method capable of recovering a PCB with a high yield, in which the leakage of the PCB to the environment does not easily occur.

[0010]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and the gist thereof is as follows. (1) In a method of recovering harmful insulating oil from an electric device using a member impregnated with the harmful insulating oil, the electric device is placed in a vacuum heating furnace, and the inside of the vacuum heating furnace is depressurized. The harmful insulating oil is characterized in that the harmful insulating oil is evaporated and the harmful insulating oil is evaporated, and the harmful insulating oil vapor is condensed and recovered on an exhaust system from a vacuum heating furnace. Collection method.

(2) 0.01 to 50 mb in the vacuum heating furnace
The method for collecting harmful insulating oil according to the above (1), wherein the pressure is reduced to ar. (3) The method for collecting harmful insulating oil according to (1) or (2), wherein the electric device is heated to 250 to 650 ° C. in a vacuum heating furnace. (4) In a method of recovering PCB from a condenser or a transformer using a member made of paper or wood impregnated with harmful insulating oil containing PCB, the condenser or the transformer is placed in a vacuum heating furnace, and the inside of the vacuum heating furnace is removed. 0.01
Reduce the pressure to 〜50 mbar and heat the condenser or transformer to 250-650 ° C.
The carbonized material impregnated with the harmful insulating oil containing methane is evaporated and the harmful insulating oil is evaporated.
A method for recovering harmful insulating oil, comprising condensing and recovering CB.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
The present invention relates to a method for recovering harmful insulating oil used in electric equipment such as a condenser and a transformer. Here, harmful insulating oil refers to PCB and its derivatives (hereinafter referred to as PC).
B, etc.).

FIG. 3A is a schematic view of a structure of a capacitor using insulating oil, and FIG. 3B is a schematic view of a structure of a capacitor element 23 as an example of an electric device using a harmful insulating substance. . The insulating oil is sealed in the casing 21, and the insulating paper 35 is used in a state of being impregnated with the insulating oil. Although the transformer is not shown, in this case, a member made of wood is used as the member impregnated with the insulating oil.

According to the present invention, PCBs and the like are collected from these electric devices by a vacuum heating method. In the vacuum heating, the above-described insulating member is carbonized, and harmful insulating oil impregnated in the insulating member is removed. It is characterized in that harmful insulating oil is recovered by condensing means provided in the exhaust system after being evaporated.

PC by vacuum heating method conventionally considered
In the B recovery method, it has been considered that when these insulating members are carbonized, PCBs and the like are adsorbed, and thus, simultaneous carbonization of the insulating members and evaporation of the PCBs and the like have not been considered at all. For example, Japanese Patent Application Laid-Open No. 9-192
No. 535 also states that "when the heating temperature reaches 220 ° C., the carbonization phenomenon is observed on the paper or papers of the transformer member, which reveals that the optimum vacuum heating temperature is around 200 ° C. In the past, carbonization of insulating members was a phenomenon to be avoided.

According to the present invention, the electric equipment is placed in a vacuum heating furnace, the inside of the vacuum heating furnace is depressurized, and the electric equipment is heated while continuing the decompression as described above. The harmful insulating oil was vaporized and the harmful insulating oil was evaporated, and the harmful insulating oil vapor was condensed and recovered on the exhaust system from the vacuum heating furnace. Then, as a preferable condition for carbonizing the member impregnated with the harmful insulating oil and evaporating the harmful insulating oil, the pressure of the vacuum heating furnace is reduced to 0.01 to 50 mbar, and the electric equipment is heated to 250 to 650 ° C. in the vacuum heating furnace. To be heated.

The reason why the pressure in the vacuum heating furnace is reduced to 0.01 to 50 mbar is that the harmful insulating oil is not sufficiently evaporated under the condition where the reduced pressure exceeds 50 mbar, and the effect is reduced even if the pressure is reduced to less than 0.01 mbar. This is because of saturation. Further, the reason for heating the electric equipment to 250 to 650 ° C.
If the temperature is lower than ℃, the carbonization of the insulating member is not sufficient, and if the temperature is higher than 650 ° C, the size of the heating device is increased.

By performing the vacuum heating in this manner, the insulating member can be carbonized and the harmful insulating oil can be evaporated. Here, since the vacuum heating is performed while the pressure in the vacuum heating furnace is continuously reduced, the generated toxic insulating oil vapor is quickly sucked into the exhaust system from the vacuum heating furnace.
On this exhaust system, the harmful insulating oil vapor is cooled and condensed by a cooling condenser or the like, and separated and recovered from exhaust gas from a vacuum heating furnace.

The exhaust gas may then be released to the atmosphere via an activated carbon filter or the like. For example, the exhaust gas may be discharged to the atmosphere after passing through two sets of activated carbon filters. In this case, a sensor is further provided between the activated carbon filter on the upstream side and the activated carbon filter on the downstream side, and The harmful substance content may be monitored.

Conventionally, it has been premised that the insulating oil enclosed in the electric device is removed by suctioning the device in advance or tilting the device. However, in the present invention, the sealing member is thermally deformed by the heating, and also the turgor pressure is generated inside the electric device to release the sealing of the device. It is possible to collect PCB and the like. Needless to say, vacuum heating may be performed after removing the insulating oil in advance as in the conventional case.

In the present invention, the pressure in the vacuum heating furnace is first started, and then the heating is started. This is because starting heating under normal pressure may cause dioxin and the like. If the pressure is reduced in advance and the inside of the vacuum heating furnace is heated from a state where the amount of oxygen is reduced, no dioxin or the like is generated by the oxidation reaction.

[0022]

Embodiments of the present invention will be described below. FIG. 1 is a schematic view showing an example of an apparatus for implementing the method for recovering harmful insulating oil of the present invention. This apparatus mainly comprises a vacuum heating furnace 1 and a vacuum heating furnace exhaust system 10. The vacuum heating furnace 1 is provided with a radiation heating type heater 3 inside, and has a structure capable of heating an object to be processed loaded inside the vacuum heating furnace 1 under reduced pressure. A vacuum heating furnace exhaust system 10 is connected to the vacuum heating furnace 1, and an exhaust gas from the inside of the vacuum heating furnace 1 is discharged into the atmosphere via the vacuum heating furnace exhaust system 10. On the vacuum heating furnace exhaust system 10, a cooling condenser 4, a vacuum pump 6,
Activated carbon filters 7 and 9 and a sensor 8 are provided.

In the vacuum heating furnace 1 of the above-described apparatus, 452
An experiment was conducted in which a condenser containing 0 g of PCB was charged and the PCB was recovered according to the method of the present invention. That is, the PCB-containing condenser 2 is charged into the vacuum heating furnace 1, and then the vacuum pump 6 is driven to reduce the pressure in the vacuum heating furnace 1,
When the pressure in the vacuum heating furnace 1 reaches about 1 mbar, radiation heating by the heater 3 is started, and then the decompression and heating in the vacuum heating furnace 1 are continued for 6 hours, and the harmful insulation in the exhaust gas is maintained by the cooling condenser 4. The oil was coagulated and collected in the collection container 5. The pressure inside the vacuum heating furnace 1 finally becomes 0.1 mbar, and the heating temperature is 390 ° C max.
Met. FIG. 2 is a chart showing changes over time in the state of the heating temperature and the pressure in the vacuum heating furnace 1.

Table 1 also shows the weight of the condenser after the recovery processing before and after the processing, and the weight of the recovered condensate. It can be seen that agglomerates corresponding to the weight of the condenser reduced by the treatment are obtained.

[0025]

[Table 1]

Further, the carbonized insulating paper was taken out of the treated capacitor, and the amount (concentration) of PCB contained therein was measured by DIN 51527 method.
Shown in As shown in Table 2, according to the method of the present invention, the PCB impregnated in the insulating paper can be reduced to less than the analysis limit of 0.02 mg / kg according to the DIN 51527 method.

[0027]

[Table 2]

Table 3 shows the amount (concentration) of PCB contained in the aggregate collected in the collection container 5 in the same manner as DIN51.
The result measured by the 527 method is shown. The concentration of PCB recovered by the method of the present invention is 34790 mg / kg, reaching almost 3.5%. This value indicates that the concentration of PCB recovered by the vacuum heating method in the prior art is 50%.
It is much higher than less than ppm.

[0029]

[Table 3]

After the harmful insulating oil was condensed, the exhaust gas from the vacuum heating furnace 1 was discharged into the atmosphere through activated carbon filters 7 and 9. A sensor 8 was provided between the activated carbon filters 7 and 9 to monitor the content of harmful components in the exhaust gas, but the harmful components remained below the measurement limit throughout the operation.

Since the condenser treated as described above contains no harmful substances, it can be treated and recycled in the same manner as ordinary scrap.

[0032]

According to the method of the present invention, there is no need to cut or crush electrical equipment before PCB recovery processing, and it is easy and safe to recover PCB from insulating members such as insulating paper. In addition, the collected PCB-containing condensate is directly collected in the container,
The spread of CB contamination can be minimized. The method of the present invention can be carried out by a device that is more compact than before, and if the treatment is carried out by a mobile plant, on-site treatment is also possible.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an example of an apparatus for implementing the present invention.

FIG. 2 is a chart showing a change over time in a state of a heating temperature and a pressure in a vacuum heating furnace 1;

FIG. 3A is a schematic diagram showing a structure of a capacitor using insulating oil. (B) Schematic which shows the structure of a capacitor element.

Claims (4)

[Claims] 1. A method for recovering harmful insulating oil from an electric device using a member impregnated with the harmful insulating oil, wherein the electric device is placed in a vacuum heating furnace, and the inside of the vacuum heating furnace is depressurized. Harmful insulation characterized by heating electrical equipment, carbonizing members impregnated with harmful insulating oil, evaporating harmful insulating oil, and condensing and collecting harmful insulating oil vapor on an exhaust system from a vacuum heating furnace. Oil recovery method. 2. The method for recovering harmful insulating oil according to claim 1, wherein the pressure inside the vacuum heating furnace is reduced to 0.01 to 50 mbar. 3. The electric equipment is placed in a vacuum heating furnace at 250 to 65.
The method for recovering harmful insulating oil according to claim 1 or 2, wherein the method is heated to 0 ° C. 4. A method for recovering PCB from a condenser or a transformer using a member made of paper or wood impregnated with harmful insulating oil containing PCB, wherein the condenser or the transformer is placed in a vacuum heating furnace. The pressure in the inside is reduced to 0.01 to 50 mbar, and the condenser or the transformer is heated to 250 to 650 ° C. while the reduced pressure is continued to carbonize the member impregnated with the harmful insulating oil including PCB and evaporate the harmful insulating oil, A method for collecting harmful insulating oil, comprising condensing and collecting PCB on an exhaust system from a vacuum heating furnace.