JP5466917B2 - Equipment and method for recovering lead sheath in PCB-contaminated OF cable - Google Patents

Description

  The present invention provides a metal sheath before separating and detoxifying PCB oil from an OF cable contaminated with insulating oil (hereinafter referred to as PCB oil) containing polychlorinated biphenyl (hereinafter referred to as PCB oil). The present invention relates to a facility for recovering metal from an OF cable by melting and a method for recovering the metal.

  An OF (Oil Filled) cable is a cable used to supply power from an ultra-high voltage substation to a primary substation and a secondary substation, and is laid mainly in the ground. As shown in FIG. 4, the OF cable 1 has a multilayer structure in which a conductor layer 1a, an insulator layer 1b, a metal sheath 1c, and an anticorrosion layer 1d are formed concentrically from the center of the cable toward the outside in the radial direction. The inside of the metal sheath 1c is filled with insulating oil.

  Conventionally, PCB, which is an organic chlorine compound, has been widely used in electrical equipment as an electrical insulating oil due to its high insulation properties. On the other hand, production was stopped in 1972 due to the harmfulness of PCB.

  After that, after the twists and turns, in 2001, the government's response, such as the enforcement of the Special Measures Law concerning the Promotion of Proper Treatment of PCB Waste (PCB Special Measures Law), has finally begun. It has come to be advanced.

PCB oil is classified into two types, high concentration and low concentration. Of these, electrical equipment such as pole transformers and capacitors that contain high-concentration PCB oil, which is expected to exceed 2 × 10 ⁷ kg nationwide, is a Japanese environmental safety project with five offices nationwide. In 2001 (JESCO), processing has been proceeding.

On the other hand, pole transformers that contain low-concentration PCB oil mixed with a very small amount of PCB for some reason, such as regeneration of electrical insulating oil, are not treated by Japan Environmental Safety Corporation (JESCO). However, the total amount is 4 × 10 ⁶ units nationwide, but the power company, which is the owner, is carrying out in-house processing, and the establishment of a processing system is a problem.

  It was confirmed in 2002 by electric power companies that electrical equipment contaminated with this low-concentration PCB oil was newly present in OF cables in addition to transformers. According to data compiled by an OF cable manufacturer in 2004, an OF cable contaminated with low-concentration PCB oil (hereinafter referred to as a PCB-contaminated OF cable) is approximately 1400 km in Japan (the amount of insulation oil is approximately 3600 km). L) is estimated to exist.

  This PCB-contaminated OF cable is still used, or even if it has been removed, it is stored unprocessed and the detoxification process has not progressed.

  Therefore, the detoxification processing method for the PCB-contaminated OF cable is still in the development stage. If adopting methods that are applied to transformers, transformers, etc., such as cleaning methods and vacuum heating separation methods, OF cables are multi-layer structures such as conductors, insulators, metal coatings, plastic coatings, etc. In the cleaning method, it is difficult for the solvent to penetrate into the inside, and it takes time to disassemble. Further, it is considered that the vacuum heating separation method has a problem that it takes a long time to raise the temperature.

  The Ministry of the Environment started an incineration demonstration test for low-concentration PCB contaminants in March 2006 to confirm that electrical equipment and the like contaminated with low-concentration PCBs can be safely and reliably detoxified. The OF cable was incinerated in November 2008 by the burner heating method.

  In the burner heating method, as shown in FIG. 5 (a), the PCB-contaminated OF cable 1 is accommodated in a drum-like processing container 101, the temperature inside the heating furnace 103 is raised by the gas burner 102, and the PCB-contaminated OF cable 1 is removed. For example, it is a method of volatilizing PCB oil by heating to 500 ° C. or higher, but it requires a dedicated heating furnace 103, the point of increasing the downstream equipment for detoxifying the exhaust gas of the gas burner 102, heating There was a problem in that the heating and cooling of the furnace 103 took time and the processing time was long.

  As a method for solving the above problem, there is a method in which PCB contaminants are placed inside the work coil, induction heated, and PCBs are separated (Patent Document 1). According to this method, it is possible to process the OF cable without disassembling, and it is advantageous that the heating rate is fast and the thermal efficiency is good for direct heating.

  In order to solve the problem of exhaust gas, the necessity of a processing furnace, and the processing time in the Japanese Patent Application No. 2009-79332 for detoxifying PCB contaminants, FIG. As shown, a PCB detoxification facility was proposed. This facility uses a metal cylindrical container 201 that contains PCB contaminants, a lid 202 that seals the cylindrical container, a coil 203 that induction-heats the cylindrical container 201, and a high-frequency power source 204. And an exhaust gas path for guiding the gas generated in the cylindrical container 201 to the heating equipment.

  By the way, in the conventional method for detoxifying a PCB-contaminated OF cable using the above-described equipment, as shown in the processing flow of FIG. 6, the OF cable is cut and accommodated in a cylindrical container 201 and heated by induction heating. The PCB oil contained in the OF cable is volatilized in the treatment 301, and the PCB oil-containing gas is sent to the secondary combustion furnace or the like to be treated in the gas treatment 302, while the heat-treated OF cable separated from the PCB oil is subjected to a decomposition process. The part which decomposed | disassembled in 303 and became the carbide | carbonized_material performed the industrial waste processing 304, About the metal sheath, it collect | recovered by the recycle process 305, The metal was reused.

  However, when the present inventors conducted a confirmation test, when the metal sheath is, for example, lead or an alloy containing lead, the metal sheath is melted and deposited on the bottom of the cylindrical container 201 during the heat treatment 301 by induction heating. In addition, a phenomenon has been confirmed that solidifies around the lower portion of the OF cable during cooling.

  FIG. 7 shows an iron cylindrical container (inner diameter: 105.3 mm) containing an OF cable (cable outer diameter: 67 mm, length: 300 mm, weight: 3.6 kg, lead sheath thickness: 0.5 mm, non-contaminated). , Outer diameter: 114.3mm, length: 320mm) installed inside solenoid type coil (inner diameter: 135mm, height: 290mm, number of turns 15 times, copper tube diameter: 8mm), 65 minutes from the start of heating Is a graph showing the test results of verifying the temperature change of the lead sheath and the cable center part when induction heating is performed at a setting of 350 ° C. from 300 ° C. and from 65 minutes to 125 minutes, and the power is turned off when 125 minutes have elapsed. . Under the above conditions, it can be seen that the lead sheath temperature exceeds 327.5 ° C., which is the melting point of lead, about 80 minutes after the start of induction heating, and lead begins to melt from the OF cable.

  For this reason, conventionally, after the heat treatment 301, it is not easy to take out the OF cable from the cylindrical container 201, and it has been necessary to grasp and pull the cable. In addition, since the metal is hardened at the bottom of the vertically long cylindrical container 201, the recovery work in the recycling process 305 is troublesome.

  Further, in the heat treatment 301, for example, when a lead sheath is treated at a high temperature, lead, which is a harmful substance, is volatilized as a gas, so that treatment for lead is required in the gas treatment 302 in a secondary combustion furnace or the like. In order to avoid this, it is desirable to collect the metal sheath before the heat treatment 301. However, if the OF cable contaminated with PCB is manually disassembled and the metal sheath is collected, In addition to the safety of the person and the secondary contamination of the cutting device, it will be extremely time consuming.

JP 2004-88016 A

  The problem to be solved by the present invention is that, in the conventional equipment and method, the metal sheath melts during the heat treatment for separating the PCB oil from the OF cable and becomes solidified at the bottom of the cylindrical container. It is difficult to take out from the cylindrical container, and it takes time to recover the metal in the recycling process. For example, when heat treatment for separating PCB oil at a high temperature without separating the lead sheath is performed, lead is volatilized during the heat treatment, and thus the gas treatment side requires treatment for lead.

The lead sheath recovery equipment in the PCB-contaminated OF cable of the present invention is
In order to solve the above-mentioned problem due to the melting of the lead sheath during the heat treatment for separating the PCB oil from the OF cable,
An apparatus for recovering lead from the OF cable by melting a lead sheath in the OF cable contaminated with insulating oil containing polychlorinated biphenyl (PCB),
A pipe for accommodating the OF cable;
A coil for induction heating the lead sheath to a temperature not lower than the melting point of lead and lower than the boiling point of PCB ;
A collection container for receiving the lead melted from the OF cable;
A holder capable of holding the OF cable and the pipe above the collection container;
Installed in the heating chamber,
A high frequency power supply for supplying a high frequency current to the coil;
The main feature is that it includes an exhaust gas path for guiding the gas generated in the heating chamber to an exhaust gas treatment facility.

Since the lead sheath recovery equipment in the PCB-contaminated OF cable of the present invention is provided with a recovery container that receives lead melted from the lead sheath of the OF cable, the lead is separated from the OF cable so that it can be recovered in an ingot state. The difficulty of taking out the OF cable from the cylindrical container and the problem of work efficiency in the recycling process can be solved.

To recover the lead sheath using the lead sheath recovery equipment in the PCB-contaminated OF cable of the present invention,
Before the insulating oil is separated from the OF cable contaminated by the insulating oil containing polychlorinated biphenyl (PCB) and detoxified, the lead sheath of the OF cable accommodated in the pipe is melted by induction heating with a coil. The lead melted from the OF cable may be recovered in the recovery container. This is the method for recovering the lead sheath in the PCB-contaminated OF cable of the present invention.

  According to the present invention, the metal sheath can be melted before being detoxified by separating the PCB oil from the PCB-contaminated OF cable, and the metal sheath can be melted and recovered in the collection container, so that the heat treatment for separating the PCB oil is performed. In this case, metals such as lead are not volatilized and the heating chamber is not contaminated. Therefore, it is possible to solve the problem that the gas treatment side needs to treat lead when separating the PCB oil. In addition, since it is not necessary to disassemble the OF cable and manually recover the metal sheath, the operator is safe, there is no problem of secondary contamination of the cutting instrument, and the working efficiency is dramatically improved.

It is a longitudinal cross-sectional view explaining the structure of the metal sheath collection | recovery equipment in PCB contamination OF cable of this invention. It is a figure explaining the other example different from FIG. 1 about the holder which comprises the metal sheath collection | recovery equipment of this invention. It is a processing flow figure of the detoxification processing method of a PCB contamination OF cable including the process of the metal sheath recovery method in the PCB contamination OF cable of the present invention. It is explanatory drawing which shows the structure of OF cable. It is a figure explaining the structure of the detoxification processing equipment of the conventional PCB pollution OF cable, (a) is a burner heating method, (b) is the equipment of an induction heating method. It is a processing flow figure of the detoxification processing method of the conventional PCB contamination OF cable. It is a graph which shows the test result which verified the temperature change of the lead sheath and cable center part when heating up the iron container which put the OF cable to 350 degreeC.

  The present invention has a problem that the metal sheath is melted during the heat treatment for separating the PCB oil from the OF cable, the difficulty of taking out the OF cable from the cylindrical container, and the trouble of the metal recovery work in the recycling process. In addition, the purpose of solving the problem of the necessity of processing for metals in gas processing is to recover by melting the metal sheath by induction heating before the heat treatment for separating the PCB oil, and dissolving it in the recovery container. It was realized by doing.

Hereinafter, various forms together with the best mode for carrying out the present invention will be described in detail with reference to the accompanying drawings.
The metal sheath recovery equipment of the present invention shown in FIG. 1 has the following configuration, for example.

  Reference numeral 6 denotes a heating chamber, a pipe 2 for housing the OF cable 1, a coil 3 connected to a high-frequency power source 7 for supplying a high-frequency current to inductively heat the metal sheath in the OF cable 1, and a melt flow from the OF cable 1 A recovery container 4 that receives the metal thus received below the OF cable 1 and a holder 5 that can hold the OF cable 1 and the pipe 2 above the recovery container 4 are installed. The gas generated in the heating chamber 6 is led to the exhaust gas treatment facility 8 through the exhaust gas path 9.

  The pipe 2 is a bottomless cylindrical member for maintaining the state in which the OF cable 1 is erected. In the example of FIG. 1, a pipe made of a ceramic material is used so as not to be induction heated by the coil 3. Used. In addition, although the example which accommodates one OF cable 1 in the inside of the pipe 2 is shown in FIG. 1, you may enlarge the diameter of the pipe 2 suitably so that a some OF cable can be accommodated.

  As the coil 3, a solenoidal coil having a shape surrounding the pipe 2 accommodating the OF cable 1 in a spiral shape is used. The closer the distance between the metal sheath and the coil 3, the better the thermal efficiency, and the metal sheath can be melted in a short time. Therefore, in the present invention, it is preferable that the entire metal sheath is efficiently induction-heated in a short time using a solenoid coil as shown in FIG.

  Moreover, in the present invention, since induction heating by the IH coil is used, compared to the conventional burner heating method equipment in which the entire OF cable is heated, only the metal sheath can be efficiently heated, and Temperature control can be performed accurately.

  In the example of FIG. 1, the holder 5 is composed of only a ceramic lattice plate. In this case, the holder 5 is used by being placed on top of the collection container 4. The holder 5 holds the OF cable 1 and the pipe 2 at a position above the collection container 4 by placing the OF cable 1 and the pipe 2 on the upper surface of the holder 5 made of a grid-like plate.

  Since the holder 5 is a grid-like plate, the melted metal can pass through the grid portion serving as a communication path. Therefore, the metal of the metal sheath melted from the OF cable 1 does not accumulate on the upper surface of the holder 5 and flows down to the collection container 4 through the holder 5. For example, a lattice-shaped plate can be used as the holder 5, but any plate that can pass molten metal may be used. For example, a plate having a required number of holes may be used.

  The recovery container 4 uses a material having heat resistance equal to or higher than the melting point of the metal of the metal sheath, and may be made of metal or nonmetal. However, as shown in FIG. 1, when the plate-like holder 5 is placed on top of the recovery container 4, the lower end of the coil 3 and the upper end of the recovery container 4 are close to each other. If it is used, there is a problem that the recovery container is heated by induction and the heating efficiency is deteriorated, or the metal melted from the OF cable 1 is not cooled.

  Accordingly, when the plate-like holder 5 is placed on the upper portion of the recovery container 4 as shown in FIG. 1, it is preferable to use, for example, a ceramic recovery container so that the recovery container 4 is not induction heated. .

  On the other hand, when the collection container 4 is made of metal, the holder 5 is provided with a communication path 5a1 through which the metal melted from the OF cable 1 passes, as shown in FIG. It is preferable to comprise a grid-like plate portion 5a for mounting the plate portion 5a and a leg portion 5b that supports the plate portion 5a at a required height position. The communication path 5a1 is a grid portion of the grid-like plate portion 5a.

  Here, the distance d1 between the lower end portion of the coil 3 and the upper end portion of the recovery container 4 is preferably set to 150 mm or more in order to secure a distance at which the recovery container 4 is not induction heated by the coil 3. Further, when the recovered lead is induction-heated, there is a problem that the heating efficiency of the lead sheath is deteriorated or the recovered lead is not cooled, so that the gap between the lower end portion of the coil 3 and the bottom surface portion of the recovery container 4 The distance d2 is preferably configured such that the recovered lead is not induction-heated at a distance of 150 mm or more. In the configuration of FIG. 2, these distances can be secured by appropriately adjusting the height of the leg 5 b.

  In addition, also when it is set as the structure which mounts the plate-shaped holder 5 on the upper part of the ceramic collection containers 4 like FIG. 1, the distance for preventing the collect | recovered lead from induction heating is 150 mm or more. Are the same. In the configuration of FIG. 1, the distance between the coil and lead is ensured by appropriately adjusting the height of the collection container 4.

  The heating chamber 6 is made of a material having heat resistance equal to or higher than the boiling point of PCB, and may be made of metal or nonmetal. In the case where the heating chamber 6 is made of metal, if the heating chamber 6 is induction-heated, the heating efficiency of the metal sheath may deteriorate, or the temperature in the heating chamber 6 may increase or burns. A distance of 150 mm or more is ensured.

  The exhaust gas path 9 is a path provided in the upper part of the heating chamber 6 in order to introduce the gas generated in the heating chamber 6 into the exhaust gas treatment facility 8 for industrial waste incineration processing. The exhaust gas treatment facility 8 includes a secondary combustion furnace that renders PCB harmless, a gas cooler that cools gas, and a filter that removes foreign matters such as dust. Moreover, you may provide the oil scrubber which melt | dissolves and removes the PCB oil in exhaust gas using an oil shower.

  In the above embodiment, the pipe 2 is made of ceramics, and the coil 3 is configured to inductively heat the metal sheath of the OF cable 1 (direct heating method). However, in the present invention, the pipe is a metal pipe. Instead of the coil 3 for induction heating the metal sheath, a configuration (indirect heating method) in which the coil for induction heating the metal pipe is installed in the heating chamber 6 may be used. In this case, the metal sheath is indirectly melted by induction heating of a metal pipe, and the metal is recovered, but the other points can be the same as in the above embodiment. In the case of the indirect heating method, for example, an iron pipe can be used. However, as long as the heat transfer coefficient is good, it may not be made of iron but may be made of other metals.

  FIG. 3 is a process flow diagram of a detoxification processing method for a PCB-contaminated OF cable including a lead sheath separation step 11 using the present invention. Since the equipment of the present invention can be incorporated in existing OF cable detoxification equipment provided in the industrial waste incineration treatment facility, in that case, it is not necessary to newly install downstream equipment.

  That is, the metal sheath recovery method of the present invention melts the metal sheath of the OF cable 1 accommodated in the pipe 2 by induction heating with the coil 3 before separating the PCB oil from the PCB-contaminated OF cable and detoxifying it. The metal melted from the OF cable 1 is recovered in the recovery container 4. In the recycle process 12, since the ingot-shaped metal can be recovered from the recovery container 4, it is easy to handle.

  The exhaust gas generated in the lead sheath separation step is introduced into the gas treatment 14 and treated in the same manner as the exhaust gas generated in the heat treatment 13 for separating the PCB oil.

  As will be described later, in the present invention, if the temperature at the time of induction heating of the metal sheath is set to be equal to or lower than the boiling point of PCB, lead can be recovered without generating toxic gas containing PCB. Considering the fact that PCB is volatilized at a high temperature, for safety, heat treatment is performed in the heating chamber 6 and an exhaust gas passage 9 for introducing gas into the exhaust gas treatment facility 8 is provided.

  15 shows the dismantling process of the OF cable after the PCB oil separation, 16 shows the industrial waste treatment of the part that has become carbide, and 17 shows the recycling process for recovering reusable metal. When the facility of the present invention is incorporated, harmful and difficult to handle lead has already been separated in the lead sheath separation step 11, and therefore, in the recycling step 17, it is only necessary to collect metals other than lead.

  To recover the metal sheath using the metal sheath recovery equipment in the PCB-contaminated OF cable of the present invention, the following is performed. In addition, the OF cable used for implementation has a cable outer diameter of 67 mm, a length of 300 mm, a weight of 3.6 kg, and the metal sheath is lead.

  First, the collection container 4 and the plate-like holder 5 are installed in the heating chamber 6, and the pipe 2 and the coil 3 are installed on the upper surface of the holder 5. The OF cable 1 is cut into a length of, for example, 1 m or less suitable for heat treatment after separating the PCB oil, and then accommodated in a ceramic pipe 2 installed inside the coil 3.

  At this time, it is preferable that the OF cable 1 is accommodated in the pipe 2 with one of the cut surfaces thereof facing downward vertically so that the lead melted from the OF cable 1 can easily flow. When a plurality of OF cables 1 are put in the pipe 2, the direction of the OF cables is aligned in parallel so that the cut surface of each of the OF cables is vertically downward.

  After the OF cable 1 was installed, the coil 3 was connected to the high frequency power source 7 and the exhaust gas path 9 was connected. Thereafter, a high frequency AC power source was supplied from the high frequency power source 7 to the coil 3, and the lead sheath of the OF cable 1 was induction-heated while adjusting the output of the high frequency power source 7 by feeding back the temperature of the lead sheath. Then, the lead sheath was melted by induction heating at a temperature not lower than the melting point of lead and lower than the boiling point of PCB.

  Here, the induction heating of the lead sheath at a temperature higher than the melting point of lead and lower than the boiling point of PCB prevents the insulating oil containing PCB from being volatilized and contaminating the inside of the heating chamber 6 during induction heating. Because. That is, in the metal sheath recovery method of the present invention, the metal sheath is not less than the melting point of the metal and less than the boiling point of the PCB so that the insulating oil containing PCB does not volatilize and contaminate the heating chamber 6 during induction heating. It is preferable to perform induction heating at a temperature of

  By the way, the melting point of lead is 327.5 ° C and the boiling point of PCB is 340 according to the safety data sheet (MSDS) of chemicals of Kanechlor (KC-300, KC-400, KC-500, KC-600). Since it is in the range of ˜375 ° C., when the metal sheath is lead, it is preferable to induction heat the lead sheath at 327.5 ° C. or more and less than 340 ° C.

  When the induction heating was completed, the high frequency power supply 7 was turned off, and the temperature in the system was lowered. When the temperature in the heating chamber 6 returned to room temperature, the recovery container 4 was taken out and observed, and it was confirmed that ingot-shaped lead could be recovered. Further, when the OF cable 1 was disassembled after collecting the lead sheath, no lead was found in the bottom of the OF cable 1.

  The present invention is not limited to the above example, and it goes without saying that the embodiments may be changed as appropriate within the scope of the technical idea described in each claim.

  For example, the coil 3 may use not only a solenoidal coil but also a planar coil. In the above embodiment, the coil 3 is held on the upper surface of the holder 5 together with the OF cable 1 and the pipe 2. However, the holding means for the coil 3 may be provided separately from the holder 5.

DESCRIPTION OF SYMBOLS 1 OF cable 2 Pipe 3 Coil 4 Collection container 5 Holder 5a Plate part 5a1 Communication path 5b Leg part 6 Heating chamber 7 High frequency power supply 8 Exhaust gas treatment equipment 9 Exhaust gas path

Claims (6)

An apparatus for recovering lead from the OF cable by melting a lead sheath in the OF cable contaminated with insulating oil containing polychlorinated biphenyl (PCB),
A pipe for accommodating the OF cable;
A coil for induction heating the lead sheath to a temperature not lower than the melting point of lead and lower than the boiling point of PCB ;
A collection container for receiving the lead melted from the OF cable;
A holder capable of holding the OF cable and the pipe above the collection container;
Installed in the heating chamber,
A high frequency power supply for supplying a high frequency current to the coil;
An exhaust gas path for guiding the gas generated in the heating chamber to an exhaust gas treatment facility, and a lead sheath recovery facility in a PCB-contaminated OF cable. The pipe is a metal pipe, and instead of the coil for induction heating the lead sheath, the lead sheath is indirectly heated to a temperature not lower than the melting point of lead and lower than the boiling point of the PCB by induction heating of the metal pipe. 2. The lead sheath recovery equipment in a PCB-contaminated OF cable according to claim 1, wherein a coil to be installed is installed in the heating chamber. The holder is
It has a communication passage through which the lead melted from the OF cable passes, and is composed of a plate portion on which the OF cable and the pipe are placed on the upper surface, and a leg portion that supports the plate portion at a required height position. 3. The lead sheath recovery facility for PCB-contaminated OF cable according to claim 1 or 2. A lead sheath recovering method using the PCB-contaminated OF cable in lead sheaths recovery equipment according to any one of claims 1 to 3,
Before the insulation oil is separated from the OF cable contaminated by the insulation oil containing polychlorinated biphenyl (PCB) and detoxified, the lead sheath of the OF cable accommodated in the pipe is melted by induction heating using the coil. and, PCB contaminated oF cable in lead sheaths recovery method comprising recovering the lead and溶流from oF cables into the collection container. The lead sheath is induction-heated at a temperature not lower than the melting point of the lead and lower than the boiling point of the PCB so that the insulating oil containing PCB does not volatilize and contaminate the heating chamber during the induction heating. The method for recovering a lead sheath in a PCB-contaminated OF cable according to claim 4. 6. The method for recovering a lead sheath in a PCB-contaminated OF cable according to claim 4 or 5, wherein the OF cable is accommodated in the pipe with one of the cut surfaces thereof facing vertically downward.

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