JP4466345B2 - Recycling method of waste cable - Google Patents

Description

  The present invention relates to a method for recycling a waste cable, and more particularly, to a method for recycling a waste cable using an oil-containing insulating paper such as an SL cable or an H cable as an insulator.

  As electric wires / cables, there are known those using a crosslinked polyethylene such as a CV cable as an insulator and those containing an oil-containing insulating paper impregnated with an insulating oil such as an SL cable or an H cable as an insulator. These wires / cables are replaced when used for a certain period because the insulator is oxidized and deteriorated after a certain period. The replaced waste cable is separated into a conductor (mainly copper) and a covering waste material (rubber, plastic, lead coat, paper, jute, tar, etc.).

  However, in the case of SL cable and H cable, the separated coating waste material may adversely affect the human body in some cases besides rubber, plastic, paper, jute, tar content, corrosion inhibitor, antioxidant, etc. Since organic substances such as polychlorinated biphenyls are contained, the disposal after the disposal is a problem. Further, since the separated rubber / plastic material is not easily decomposed, it becomes a problem that copper, which is a substance that can be recovered and reused (hereinafter referred to as “valuable material”), cannot be recovered smoothly. ing.

  By the way, the cable is composed of a plurality of materials around the conductor and has a very complicated structure. 2 and 3 are cross-sectional views showing an example of a cable including oil-containing insulating paper. In the SL cable shown in FIG. 2, after winding the insulating paper 17 on the wire conductor 18, the single core lead covered cable 3 with the lead covered 16 is finished together with the interposing jute 19 and finished into a circular shape. A chloroprene sheath 13 is provided on the top. In the H cable shown in FIG. 3, an insulating paper 25 is wound on a line conductor 27, a metal shielding tape 26 is wound thereon, a jute 28 is put in a gap with the three cores more closely aligned, and a circular finish is formed thereon. After winding the metal strip 24, it is dipped and oiled to provide a lead coating 23.

  In order to take out the conductor (copper wire) from the SL cable or H cable, it has been through several work processes such as tar removal, cable sheath removal, lead removal, interstitial jute removal, lead removal, and insulation paper removal. The method of cutting and removing in order from the outer coating is adopted.

  However, since the shape of the cable is complicated, the cable disassembly work requires a plurality of human hands, and the disassembly requires a long time. Moreover, since it is a cutting operation, there is a problem that it involves a dangerous operation. In addition, since the cable contains insulating paper containing insulating oil, it may contain harmful substances in the human body used as an additive for insulating oil, so be careful not to scatter them. Need to be separated and processed separately. At this time, if there is adhesion to adjacent members, it is necessary to separate and clean them, which further complicates the work.

  As a method for disassembling a waste cable, for example, Japanese Patent Laid-Open No. 2000-279927 (Patent Document 1) discloses that copper is efficiently used from the waste cable in order to reuse or dispose of the coated waste material collected and disassembled. A method of removing well has been proposed. In this publication, plastic-covered waste cables are crushed, separated into copper and coated waste due to the difference in specific gravity, and the separated pieces of the coated waste are selected with a classifier and the size of the crushed pieces is less than 3 mm. A method is disclosed in which the copper content is separated from the coated waste material crushed pieces by the specific gravity difference by water.

Japanese Patent Laid-Open No. 2001-191046 (Patent Document 2) is suitable for the treatment of long products such as electric wires and cables as an improvement technique of a conventional batch or semi-batch treatment apparatus using subcritical water. A continuous treatment method for electrical wire and cable waste has been proposed. In a reaction vessel equipped with a reaction cylinder and a seal body having electric wire / cable insertion holes inserted at both ends of the reaction cylinder, the electric wire / cable waste with the rubber / plastic coating exposed is supercritical water or by catalytic reaction with subcritical water, it is continuous processes wire and cable waste by decomposing the rubber and plastics.

  However, Patent Document 1 relates to a technique for efficiently separating copper from waste material, and thus, the coated waste material can be reused as a raw material for blast furnaces, or even when landfilled. Although there is an advantage that it can be disposed of without worrying about heavy metal contamination, it is not a technology that can disassemble the entire disposal cable.

  In Patent Document 2, the object to be decomposed is rubber / plastic such as cross-linked polyethylene, and the cross-linked polyethylene is only modified to non-cross-linked polyethylene by the decomposition treatment, and there is no mention of insulating paper, tar, and various additives. Not done. In this method, the pressure of the reaction cylinder is held by the multiple sealing bodies. However, considering the danger when the pressure balance is broken, an explosion-proof casing or the like is required and the cost is increased.

  The present invention has been made in view of the above-mentioned conventional problems, and is a recycling method for waste cables (SL cable, H cable, etc.) using oil-containing insulating paper as an insulator without using plastic as an insulator. , Pre-disassembly treatment is easy, the work time can be greatly shortened and dangerous work can be avoided, material can be recycled by quick and easy removal of valuable conductors, and the organic matter contained in the cable It aims at providing the recycling processing method of a waste cable which enables thermal recycling.

  In order to solve the above-mentioned problems, the present inventors diligently studied. As a result, the recovered SL can be recovered easily by hydrothermally treating the cut SL cable, and the decomposition product of organic matter in the cable is also reused. The inventors have found that it is possible to arrive at the present invention.

That is, the present invention is as follows.
1) A waste piece made of oil-impregnated insulating paper as an insulator is cut into a longitudinal direction, and 7 to 13 times (mass ratio) of water is supplied to the reaction vessel with respect to the cut piece, and the temperature is 450 to 650. By hydrothermal treatment by hydrothermal reaction at a temperature of 23 ° C. and a pressure of 23 to 30 MPa, the organic matter in the discarded cable is decomposed , the decomposition product gas is recovered , and from the cable residue after the decomposition Recycling method of waste cable, characterized by recovering valuable metals,
2 ) The recycling method for waste cables according to 1 ) above, wherein the organic substance contains at least one selected from tar, insulating paper, corrosion inhibitor, antioxidant and organochlorine compound and a covering rubber.
3 ) The waste cable recycling method according to 1) or 2) above, wherein the organic decomposition gas is thermally recycled, and
4 ) The recycling method for waste cables according to any one of 1) to 3 ) above, wherein valuable metals are material recycled.

  As described above, according to the present invention, since the cable is simply cut into round cuts, the pre-treatment of the cable can be performed as a simple mechanical work, and the working time can be greatly shortened and dangerous work can be avoided. In addition, since the organic coating material can be efficiently decomposed through the exposed cable cross section regardless of the presence or absence of harmful substances, physical removal work of the cable coating material is unnecessary, and the cable coating material and the conductor Can be quickly separated, and valuable conductors (copper wires) can be quickly and easily removed. Furthermore, the organic matter contained in the cable can be thermally recycled, and the metal can be material recycled.

  The recycling method of the waste cable of the present invention decomposes the organic matter in the waste cable by hydrothermally treating a cut piece of the waste cable having an oil-impregnated insulating paper such as an SL cable or an H cable as an insulator. At the same time, valuable metals are recovered from the cable residue after decomposition.

  Prior to the disassembling process, in order to expose the cross section of the cable, a preprocessing step of cutting the waste cable into a ring in the longitudinal direction is performed. The cutting length is not particularly limited as long as it can be filled into the reaction vessel. A waste cable cut piece and water as a solvent are fed into the reaction vessel and heated so that the temperature and pressure are maintained within the desired temperature and pressure range. Alternatively, after putting the waste cable cut piece into a pressure-resistant reaction vessel such as an autoclave, the solvent in the supercritical state or the subcritical state is pressure-fitted into the pressure-resistant reaction vessel, and the temperature and pressure in the pressure-resistant reaction vessel are adjusted to a desired temperature. And heated to remain within the pressure range. The reaction vessel is not particularly limited, and a general reaction vessel for high temperature resistance and high pressure resistance such as an autoclave can be used.

  The waste cable in the reaction container comes into contact with water, which is a solvent, at high temperatures and pressures, and the rubber coating, intervening jute, and insulating paper on the surface are decomposed, and gases such as hydrocarbons, carbon monoxide, carbon dioxide, and hydrogen are released. Generate. At this time, in addition to organic substances such as tar, corrosion inhibitor, and antioxidant, which may coexist, organic chlorine compounds such as polychlorinated biphenyls are also decomposed, and gas is similarly generated. Along with the decomposition of the organic matter, the conductor (copper wire) and the lead coat are separated from the organic matter.

  The reason for using water as a solvent is that it is highly safe during handling and can reduce the environmental burden.

In the present invention, the reaction temperature and reaction pressure at the time of contacting the cable and water, temperature 450 to 650 ° C., the range of pressure 23MPa～30MPa. By controlling to such a range, even when an organochlorine compound is contained in the cable, these can be quickly decomposed into harmless gases. More desirably, the reaction temperature is 600 ° C. to 650 ° C., and the reaction pressure is 23 MPa to 27 MPa. In view of the rapidity of reaction and decomposability, the supercritical state is preferable.

  The reaction time is usually 30 to 120 minutes, preferably 50 to 70 minutes. If the reaction time is too short, decomposition of the organic matter becomes insufficient, and if the reaction time is too long, the reaction reaches an equilibrium state, which is meaningless.

  Moreover, in order to accelerate | stimulate the decomposition reaction of a cable coating | covering material, you may add hydrogen peroxide, oxygen, etc. to a solvent as needed.

The amount of solvent supplied to the reaction vessel varies depending on the type of cable, but the solvent is added 7 to 13 times (mass ratio) to the cable . When the amount of the solvent is less than 7 times, the decomposition of the organic matter becomes insufficient. On the other hand, when the amount exceeds 13 times, the waste liquid increases and is wasted. In consideration of decomposition efficiency, decomposition rate, ease of recovery, and the like, it is more preferable to add 9 to 11 times (mass ratio) of the solvent to the cable.

  Next, a method for recycling a waste cable according to the present invention will be described with reference to the drawings. FIG. 1 shows a flowchart of a recycling method according to an embodiment of the present invention.

  The waste cable 2 as a raw material is supplied to the pretreatment step 3 and cut, and supplied to the reaction vessel 4 together with the solvent (water) 6 and reacted under predetermined conditions. The organic matter contained in the cable is decomposed in the reaction vessel, and the decomposition product gas is recovered. Decomposition residue contains valuable metals such as conductors (copper wire) and lead coating separated from the coating material, as well as solvents, etc., but valuable metals can be easily removed by performing operations such as filtration on the decomposition residue. Can be separated and recovered.

  The recovered decomposition product gas 7 can be thermally recycled and used as boiler fuel, gas engine fuel, or the like. Further, the recovered valuable metal 8 can be recycled as a conductor or the like by material recycling.

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

Example 1
SL cable piece 13g and water 100g cut to a length of about 10 to 20 mm were introduced into a pressure-resistant reaction vessel (volume 100 mL), and the pressure-resistant reaction vessel was heated to maintain the temperature and pressure in the vessel at 500 ° C. and 25 MPa. . The reaction was continued while collecting decomposition gas generated during the reaction, and the above temperature and pressure were maintained for about 60 minutes until generation of decomposition gas was not observed.

  When the inside of the reaction container after the treatment was observed, 5.11 g was confirmed as a residue obtained by disassembling the cable. The decomposition gas was 5.91 g, and the organic matter in the waste liquid was 2.84 g.

(Example 2)
As in Example 1, the pressure resistant reactor was heated to maintain the temperature and pressure in the vessel at 600 ° C. and 25 MPa. The reaction was continued while collecting decomposition gas generated during the reaction, and the above temperature and pressure were maintained for about 60 minutes until generation of decomposition gas was not observed.

  When the inside of the reaction vessel after the treatment was observed, 5.63 g was confirmed as a residue obtained by disassembling the cable. The cracked gas was 5.74 g, and the organic matter in the waste liquid was 3.22 g.

(Example 3)
Into a pressure-resistant reaction vessel (volume: 100 mL), 14 g of SL cable piece cut to a length of about 10 to 20 mm, water 100 g, and 3.6 L of oxygen gas are introduced, and the pressure-resistant reaction vessel is heated to control the temperature and pressure in the vessel. It was kept at 600 ° C. and 25 MPa. The reaction was continued while collecting decomposition gas generated during the reaction, and the above temperature and pressure were maintained for about 60 minutes until generation of decomposition gas was not observed.

  When the inside of the reaction container after the treatment was observed, 3.45 g was confirmed as a residue obtained by disassembling the cable. The decomposition gas was 11.71 g, and the organic matter in the waste liquid was 4.12 g.

  FIG. 4 shows the material balance of gas, liquid, and residue generated in the experiments of Examples 1 to 3, and FIG. 5 shows the ratio of each component to the total amount of components after the decomposition treatment. From the results of FIG. 4, it can be seen that organic substances are decomposed and gas is generated. From the results shown in FIG. 5, it can be seen that the decomposition products increase when the reaction temperature is high, and that the decomposition products increase further when oxygen is introduced.

It is a flowchart of the recycling processing method of a waste cable. It is sectional drawing of SL cable. It is sectional drawing of H cable. It is a graph which shows the material balance after SL cable decomposition | disassembly. It is a graph which shows the amount of each component after SL cable decomposition | disassembly.

Explanation of symbols

1 Flowchart of waste cable recycling treatment method 2 Waste cable 3 Pretreatment process 4 Reaction vessel 6 Solvent (water)
7 Gas 8 Metal
11 Carbon paper 12 Chloroprene friction canvas 13 Chloroprene sheaths 14 and 15 Chloroprene sheathing belt 16 Lead coating 17 Oil-impregnated insulating paper 18 Conductor 19 Interposing jute 21 Chloroprene friction canvas 22 Chloroprene 23 Lead coating 24 Copper wire woven fabric strip 25 Core insulation 26 Shielding layer 27 conductor 28 intervening jute

Claims (4)

A waste piece having an oil-impregnated insulating paper as an insulator is cut into a longitudinal direction, and 7 to 13 times (mass ratio) of water is supplied to the reaction vessel with respect to the cut piece, and the temperature is 450 to 650 ° C. By hydrothermally reacting at a pressure of 23-30 MPa for 0.5-2.0 hours to decompose the organic matter in the waste cable and recover the decomposition product gas, valuable metals from the decomposed cable residue Recycling method of waste cable, characterized by collecting the cable. The method for recycling a waste cable according to claim 1 , wherein the organic substance contains at least one selected from tar, insulating paper, a corrosion inhibitor, an antioxidant, and an organic chlorine compound and a covering rubber. The method for recycling a waste cable according to claim 1 or 2 , wherein the organic decomposition gas is thermally recycled. The recycling method of a waste cable according to any one of claims 1 to 3 , wherein the valuable metal is material recycled.

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