JP2013184089A - Treatment method and treatment device for pcb-containing waste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a treatment method and treatment device for PCB-containing waste capable of smoothly controlling a temperature in heating, capable of evenly heating the waste, and capable of volatilizing PCB in treatment for detoxifying the PCB in which a small amount of PCB adheres to electric equipment or the like.SOLUTION: In a method for treating PCB-containing waste, the PCB-containing waste 4 is carried into a continuous heating furnace 2, and heated at 850-950°C for 4-6 hours, the PCB is volatilized from the waste 4, and then, the gas discharged from the heating furnace 2 is heated in a gas combustion furnace 24 at a temperature of 1,100°C or higher for two seconds or more, and the gas containing PCB is burned at a high temperature, and is detoxified. The atmosphere in the heating furnace 2 is stirred by a fan 31.

Description

  The present invention relates to a method and apparatus for treating PCB-containing waste for detoxifying waste contaminated with PCB.

  PCB is a general term for compounds in which hydrogen of biphenyl is substituted with chlorine, and has been widely used in insulating oils for capacitors and transformers because it is chemically stable and excellent in insulating properties. However, due to its high toxicity, manufacturing, importation and use were prohibited in 1972, and the “PCB Special Measures Law” was enacted in 2001 and must be processed by 2016. It has become.

  Conventionally, as PCB processing, solvent cleaning or vacuum heating separation processing has been performed. For example, Patent Document 1 describes a processing method in which a processing object containing low-concentration PCB is incinerated or baked in a rotary kiln, and exhaust gas discharged from the rotary kiln is decomposed in a secondary combustion chamber. In addition, in the batch type incineration process, heating must be stopped when the processed product is put into and out of the furnace, and inevitably loss occurs. For example, continuous incineration as described in Patent Document 2 is performed. A processing system has been proposed.

  In Patent Document 3, by adopting a heat separation treatment method in which a trace amount of PCB-containing insulating oil adhering to electrical equipment or the like is heated and volatilized in a continuous furnace, and the combustion gas is incinerated by an exhaust gas treatment means, It is described that a small amount of PCB-containing waste electrical equipment can be processed efficiently and safely.

JP 2010-75848 A JP 2011-110450 A JP 2011-56504 A

  However, in the conventional incineration method, the configuration of the incinerator is complicated, and the processing is troublesome, so that it is difficult to reduce the cost. Furthermore, in the heat treatment by a continuous furnace as described in Patent Document 3, the inside of the furnace is not heated evenly, and there are cases where baking occurs in part.

  The present invention has been made in view of the above problems, and in the process of detoxifying PCB-containing waste having a small amount of PCB attached to electrical equipment or the like, temperature control during heating can be smoothly performed, and waste An object of the present invention is to provide a processing method and a processing apparatus for PCB-containing waste that can uniformly heat the PCB and volatilize the PCB.

  In order to solve the above problems, the present invention carries PCB-containing waste into a continuous heating furnace and heats it at 850 ° C. to 950 ° C. for 4 to 6 hours to volatilize PCB from the waste. Then, in the method for treating PCB-containing waste, the gas discharged from the heating furnace is heated in a gas combustion furnace at 1100 ° C. or more for 2 seconds or more, and the gas containing PCB is burned at a high temperature to render it harmless. Provided is a method for treating PCB-containing waste, wherein the atmosphere in the furnace is stirred with a fan.

  In this processing method, the fan may be arranged in a section until the temperature of the heating furnace is raised to 850 ° C. or higher. It is preferable to heat the waste in an oxidizing atmosphere. Further, the waste may be a transformer after draining a trace amount of PCB-containing insulating oil.

  In addition, according to the present invention, the PCB-containing waste is heated at 850 ° C. to 950 ° C. for 4 to 6 hours to continuously volatilize PCB, and the gas discharged from the gas outlet of the heating furnace The heating furnace is a continuous furnace including a carry-in standby chamber, a treatment chamber having a temperature raising unit and a temperature holding unit, and a carry-out standby chamber in order, A door that can be opened and closed is provided between the chamber and the heating chamber, and between the processing chamber and the unloading standby chamber, and a fan for stirring the atmosphere in the processing chamber is provided at the ceiling of the processing chamber. A PCB-containing waste treatment apparatus is provided.

  In this processing apparatus, the fan is preferably provided in the temperature raising unit. Further, the exhaust gas treatment means may be constituted by a gas combustion furnace for burning the gas discharged from the heating furnace at 1100 ° C. or higher, a cooling tower, a neutralization / dust collector, and a chimney.

  According to the present invention, it is possible to promote convection in a heating furnace, perform temperature control smoothly, perform proper heat treatment, and volatilize PCB.

It is a schematic diagram of the processing device of PCB content waste concerning the present invention. It is a plane sectional view of the heating furnace of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows an example of a PCB-containing waste processing apparatus according to the present invention. The processing apparatus 1 includes a continuous heating furnace 2 that heats the PCB-containing waste 4 and an exhaust gas processing means 3 that processes the exhaust gas generated in the heating furnace 2. The heating furnace 2 includes a carry-in standby chamber 11, a processing chamber 12, and a carry-out standby chamber 13. The processing chamber 12 includes a temperature raising unit 14 that raises the temperature of the PCB-containing waste 4 to be processed to 850 ° C. or higher, and 4 to 6 hours at 850 ° C. to 950 ° C. while conveying the waste 4 in the carrying-out direction. A heating temperature holding unit 15 and a cooling unit 16 are provided. The heating unit 14 and the holding unit 15 are appropriately provided with a number of burners (not shown) for heating the inside of the heating furnace 2 to a predetermined temperature. Doors 17 and 18 that can be opened and closed by hydraulic pressure or the like are provided between the carry-in standby chamber 11 and the temperature raising unit 14 and between the cooling unit 16 and the carry-out standby chamber 13. Further, a door may be provided between the temperature holding unit 15 and the cooling unit 16 in the processing chamber 12. By using the heating furnace 2 as a continuous furnace, the temperature loss is less than that in a batch-type furnace, which is efficient, and a large amount of waste can be processed.

  A gas discharge port 21 for discharging exhaust gas in the processing chamber 12 of the heating furnace 2 is provided on the ceiling of the processing chamber 12. The gas discharge port 21 is provided on the ceiling of the temperature raising unit 14 heated to 850 ° C. or higher. The gas discharge port 21 is connected to the gas introduction port 23 of the gas combustion furnace 24 of the exhaust gas processing means 3 through the flue 22. The gas combustion furnace 24 is a combustion furnace that can obtain a sufficient temperature and residence time, such as a rotary kiln, and burns the exhaust gas from the heating furnace 2 at 1100 ° C. or more for 2 seconds or more.

  Although the position of the gas discharge port 21 is not limited to the example of FIG. 1, the door 17 between the carry-in standby chamber 11 and the processing chamber 12 is not overheated, so that exhaust is performed near the door 17 on the carry-in standby chamber 11 side. Are preferred. Further, since the temperature raising unit 14 generates a large amount of combustion gas, it is preferable to exhaust the temperature raising unit 14. As a result, in the temperature holding unit 15, heat is transferred from the carry-out side to the carry-in side. Can be raised. Therefore, as shown in FIG. 1, it is preferable to provide near the carry-in waiting room 11. Further, the temperature raising unit 14 may be provided with a plurality of gas discharge ports 21 for exhaust.

  The exhaust gas treatment means 3 includes the gas combustion furnace 24 described above, a cooling tower 25 connected to the gas combustion furnace 24, a bag filter 26, a deodorization tower 27, an induction exhaust fan 28, and a chimney 29. In the present invention, the exhaust gas treatment means 3 is not limited to these configurations.

  Furthermore, in the present invention, a plurality of fans 31 are provided on the ceiling of the temperature raising unit 14 of the processing chamber 12. As shown in FIGS. 1 and 2, for example, the fan 31 is installed at a total of about six locations, two at the left and right in the width direction with appropriate intervals in the conveyance direction of the waste 4. . These fans 31 are always operated when the heating furnace 2 is in operation. The position and the number of fans 31 are not limited to the example shown in the figure, but by providing them in the temperature raising unit 14 or at least the first half of the temperature holding unit 15, the temperature distribution can be made uniform and the temperature can be adjusted smoothly. The convection for discharging the gas toward the gas discharge port 21 is efficiently generated.

  The PCB-containing waste 4 is stored in a container such as a drum can, for example, and placed on the carriage 32 in a state where the upper part of the container is opened, and subjected to continuous heat treatment. As shown in FIG. 1, the waste 4 is preferably carried on the carriage 32 via a grate 33 or the like and conveyed in the heating furnace 2. Heated from the bottom surface of the waste 4 through the lattice gap of the grate 33, and even if the waste 4 or the bottom surface of the container containing the waste 4 is distorted or deformed, it is stable on the lattice. Can be installed.

  The doors 17 and 18 of the heating furnace 2 can be reliably sealed by being pushed by hydraulic pressure or the like. In the heating furnace 2, the pressure in the furnace is generated by incineration gas or the like, but the gas in the heating furnace 2 is always sucked through the gas discharge port 21 by the induced exhaust fan 28, and thus the processing chamber 12. The inside becomes a negative pressure with respect to the external atmospheric pressure, and the gas in the processing chamber 12 does not leak to the outside of the heating furnace 2.

  Hereinafter, a processing procedure using the processing apparatus 1 of the present invention will be described.

  The object to be treated according to the present invention is waste 4 containing PCB such as electrical equipment and cables contaminated by insulating oil containing a trace amount of PCB. Specifically, for example, a trace amount of PCB containing insulating oil is used. A transformer after draining, or a cut OF cable (oil-insulated paper insulated cable). The waste 4 is placed on the carriage 32 as it is or in a container such as a cable. In the case of a transformer, after draining the PCB-containing insulating oil, it is placed on the carriage 32 with its upper part opened. In the case of an OF cable, it is cut perpendicular to the axial direction of the cable so that the cross section is exposed, put in a container and placed on the carriage 32. This container is made of a material that can hold the cut OF cable in an upright state and can withstand the heat in the heating furnace 2. For example, a steel drum can is used. And the upper part of a container is open | released so that the gas generated by heating may not remain in a cable. In the implementation of the present invention, the OF cable may be processed without being accommodated in the container, but can be processed efficiently by being processed in the container.

  The PCB-containing waste 4 placed on the carriage 32 opens the door 17 from the carry-in standby chamber 11 of the heating furnace 2 and carries it into the processing chamber 12. After the temperature is raised to 850 ° C. or higher, the temperature holding unit 15 is heated for 4 hours to 6 hours while being held at 850 ° C. to 950 ° C. This heating is preferably performed in an oxidizing atmosphere. If the heating temperature is low, volatilization of oil or the like may not progress, and if it is too high, the cost increases. Further, when heating, a constant temperature increase width is preferable because the amount of combustion gas generated can be controlled to be constant. Further, the heat treatment in the treatment chamber 12 is preferably performed in an oxidizing atmosphere from the viewpoint of reducing the amount (mass, volume) of the incineration residue, and the oxygen concentration is preferably 10% or more. The waste 4 is transported by a pusher, for example, and transported at a constant speed in the direction of the arrow in the figure. By this heating, the PCB can be volatilized and removed from the waste 4 contaminated with the PCB together with the PCB-containing liquid. The treated waste 4 is then cooled by the cooling unit 16. In the present invention, by providing the fan 31 in the processing chamber 12 of the heating furnace 2, the temperature inside the processing chamber 12 rises efficiently and evenly, and the flow of the exhaust gas to the exhaust gas treatment means 3 is made smooth. . Therefore, troubles such as burn-in that have conventionally occurred can be prevented, and the PCB-containing waste 4 can be treated stably. The waste 4 cooled by the cooling unit 16 is conveyed to the unloading standby chamber 13 with the door 18 opened.

  In the exhaust gas treatment means 3, a treatment for making the exhaust gas discharged from the heating furnace 2 harmless is performed. The exhaust gas containing PCB generated in the processing chamber 12 of the heating furnace 2 is sent from the gas discharge port 21 to the gas combustion furnace 24 through the flue 22 and heated in the gas combustion furnace 24 at 1100 ° C. or more for 2 seconds or more. Is done. The organic component containing PCB in the exhaust gas can be decomposed by burning the exhaust gas at 1100 ° C. or higher for 2 seconds or more. In order to increase the exhaust efficiency of a large amount of combustion gas generated in the temperature raising unit 14, a plurality of the flue 22 may be provided in the traveling direction of the waste 4 and connected to the gas combustion furnace 24. Further, a flue for using the remaining heat of the temperature holding unit 15 in the temperature raising unit 14 can be provided. Further, a flue may be provided on the ceiling of the carry-in waiting room 11 to adjust the temperature rise.

  The exhaust gas after the PCB is burned at a high temperature in the gas combustion furnace 24 is cooled in the cooling tower 25, neutralized by adding a neutralizing agent such as slaked lime or activated carbon, collected by the bag filter 26, and collected as solid matter. Becomes fly ash, and the gas is deodorized by the deodorization tower 27 and then discharged from the chimney 29.

  The treated transformer is disassembled, and the case is used as a scrap source for electric furnaces and converters. The transformer core taken out from the case cuts the copper coil by a mobile shear and separates the coil wire and the core. Of the separated cores, if they meet the criteria for specially managed industrial waste, they can be used directly as scrap sources. Moreover, the separated copper coil and combustible material can be burned to melt the copper coil and be recycled as copper.

  As mentioned above, although preferred embodiment of this invention was described, this invention is not limited to this example. It is obvious for those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea described in the claims. It is understood that it belongs to.

Transformers and internal components contaminated with insulating oil containing 0.67 to 0.68 mg / kg PCB were processed with the processing apparatus of the present invention. First, the transformer and the internal member were heated in the heating furnace 2 at 875 ° C. for 4 hours. The PCB concentration after the treatment by the heating furnace 2 was less than 0.01 μg / 100 cm ^{2 for the} iron core, less than 0.001 mg / kg for the coil, and 0.99 ng / g-dry for the burning shell. The exhaust gas from the heating furnace 2 burned in the gas combustion furnace 24 at 1125 ° C. for 2 seconds or more was discharged from the chimney 29 through the cooling tower 25, bag filter 26 and deodorization tower 27 shown in FIG. The PCB content of the dust collection ash collected by the bag filter 26 was 1.2 ng / g-dry, and the PCB content of the exhaust gas discharged from the chimney 29 was 2.5 ng / Nm ³ . Both were very low and PCB processing was performed properly.

  On the other hand, when a fan was not provided in the heating furnace, baking occurred and PCB processing could not be performed.

  The PCB-containing waste processing method and PCB-containing waste processing apparatus of the present invention efficiently and safely removes trace amounts of PCB-containing insulating oil adhering to waste electrical equipment such as transformers and OF cables (oil-immersed paper insulating cables). Can be processed.

DESCRIPTION OF SYMBOLS 1 Processing apparatus 2 Heating furnace 3 Exhaust gas treatment means 4 Waste 11 Carry-in waiting room 12 Processing chamber 13 Carry-out waiting room 14 Temperature rising part 15 Temperature holding part 16 Cooling parts 17 and 18 Door 21 Gas discharge port 22 Flue 23 Gas introduction port 24 gas combustion furnace 25 cooling tower 26 bag filter 27 deodorization tower 28 induction exhaust fan 29 chimney 31 fan

Claims (7)

The PCB-containing waste is carried into a continuous heating furnace, heated at 850 ° C. to 950 ° C. for 4 to 6 hours to volatilize PCB from the waste, and then discharged from the heating furnace. In a method for treating PCB-containing waste, which is heated at 1100 ° C. or higher for 2 seconds or more in a gas combustion furnace and detoxified by high-temperature combustion of a gas containing PCB,
A method for treating PCB-containing waste, wherein the atmosphere in the heating furnace is stirred with a fan.   2. The method for treating PCB-containing waste according to claim 1, wherein the fan is disposed in a section until the temperature of the heating furnace is increased to 850 ° C. or more.   The method for treating PCB-containing waste according to claim 1 or 2, wherein the waste is heated in an oxidizing atmosphere.   The method for treating PCB-containing waste according to any one of claims 1 to 3, wherein the waste is a transformer after a trace amount of PCB-containing insulating oil has been drained. A heating furnace in which PCB-containing waste is heated at 850 ° C. to 950 ° C. for 4 to 6 hours to volatilize PCB continuously, and an exhaust gas treatment means for treating the gas discharged from the gas outlet of the heating furnace, Have
The heating furnace is a continuous furnace provided in order with a carry-in standby chamber, a processing chamber having a temperature raising unit and a temperature holding unit, and a carry-out standby chamber. There is a door that can be opened and closed between the waiting rooms.
A PCB-containing waste processing apparatus, wherein a fan for stirring the atmosphere in the processing chamber is provided on the ceiling of the processing chamber.   6. The PCB-containing waste processing apparatus according to claim 5, wherein the fan is provided in the temperature raising unit.   The exhaust gas treatment means includes a gas combustion furnace for burning the gas discharged from the heating furnace at 1100 ° C or higher, a cooling tower, a neutralization / dust collector, and a chimney. The processing apparatus of the waste containing PCB described in 1.

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