JP2009142819A - Treating method and apparatus for material contaminated with polychlorinated biphenyl - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a treating method and apparatus that can treat collectively and quickly contaminated materials of various properties and polychlorinated biphenyl (PCB)concentrations such as sludge and rag contaminated with PCB; industrial products containing trace amount of PCB such as pressure-sensitive paper and a fluorescent lamp ballast; and PCB-storing vessels made of resin, steel, concrete or the like. <P>SOLUTION: The materials contaminated with polychlorinated biphenyl are treated in a plasma decomposer and then exhaust gases from the decomposer are treated for 1 to 5 seconds in a thermostatic chamber kept at 1,100 to 1,400°C. The system at the downstream side of the plasma decomposer is kept at subatmospheric pressure with two inducing draft fans of the first fan and the second fan. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method and an apparatus for detoxifying contaminants such as sludge, waste, pressure sensitive paper, and fluorescent light ballast contaminated with polychlorinated biphenyl (PCB).

  As is well known, polychlorinated biphenyl (PCB) is a chemically non-flammable substance that has high electrical insulation properties, low vapor pressure, and low volatility. It was widely used as an insulating oil for electrical components such as capacitors and capacitors, and as a heat medium in chemical processes, but due to the adverse effects on the human body caused by trace amounts of dioxins contained as impurities in the PCB, and other environmental reasons, Currently it is prohibited.

  However, there are cases in which the formerly used components remain as trace components in transformers, condensers, etc., and how to decompose them is an important issue. Therefore, at present, a detoxification treatment plan for a device using a large amount of PCB itself, oil containing PCB, and PCB is being promoted, and various methods have been implemented as its method and its apparatus. For example, when processing a transformer or the like, a method is employed in which oil removal, decomposition, and disassembly are performed as in Patent Documents 1 and 2 below, and each disassembled part is cleaned.

  However, such a method has a problem that the entire work of disassembling and cleaning takes time, and the work becomes complicated, resulting in an increased risk of contamination expansion. Such oil removal, disassembly, disassembly, etc. can be applied to large equipment such as heavy electrical equipment, but it is difficult to apply to small equipment, and the cost for processing does not match. It becomes. Incidentally, as the processing target scheduled in the detoxification processing plan, the number of small devices is overwhelmingly larger than the number of large devices.

  On the other hand, sludge and waste generated in the PCB manufacturing process, pressure sensitive paper, fluorescent lamp stabilizers, etc., but a large amount of industrial products including PCB, containers and buildings that stored PCB, underground pit concrete, etc. In addition, since PCB is impregnated, these detoxification treatments are also necessary. However, in such a wide variety of pollutants, the PCB concentration, combustible / incombustible / moisture ratio, etc. Since the properties are not constant, there is also a problem that these cannot be processed at once.

JP 2003-236493 A JP 2003-318050 A

  The present invention has been made to solve such problems. Industrial products containing a small amount of PCB such as sludge, waste, pressure-sensitive paper, and fluorescent lamp stabilizer contaminated with PCB, as well as resin, steel, and concrete. It is an object of the present invention to provide a processing method and apparatus capable of quickly and simultaneously processing contaminants whose properties and PCB concentration are not constant, such as a PCB storage container manufactured by the above.

  In order to solve such problems, the present invention has been made as a treatment method and apparatus for contaminants contaminated with polychlorinated biphenyl. The invention according to claim 1 relating to the treatment method comprises polychlorinated biphenyl. After the pollutant contaminated in step 1 is decomposed by the plasma decomposition apparatus 1, the exhaust generated by the decomposition of the contaminant is retained in the constant temperature chamber 2 maintained at a temperature of 1100 ° C. to 1400 ° C. for 1 to 5 seconds. The system on the downstream side of the plasma decomposition apparatus 1 is maintained at a pressure lower than the atmospheric pressure by the two induction fans 14 of the first induction fan 14 and the second induction fan 15.

  According to a second aspect of the present invention, in the method for treating contaminants contaminated with the polychlorinated biphenyl according to the first aspect, the flow path to the plasma decomposition furnace 8 upstream of the second induction fan 15 is more than atmospheric pressure. It is characterized by maintaining a low pressure. Furthermore, the invention according to claim 3 is the method for treating contaminants contaminated with polychlorinated biphenyl according to claim 1 or 2, wherein the flow path in the system on the downstream side of the plasma decomposition apparatus 1 is partially branched to circulate the flow. By forming a passage and circulating exhaust gas through the circulation flow path, the pressure in the furnace of the plasma decomposition apparatus 1 is controlled to a constant pressure lower than the atmospheric pressure.

  Furthermore, the invention according to claim 4 relating to the processing apparatus is a plasma decomposition apparatus 1 for decomposing contaminants contaminated with polychlorinated biphenyl, and exhaust gas generated from the plasma decomposition apparatus 1 at a temperature of 1100 ° C. to 1400 ° C. A constant temperature chamber 2 for 1 to 5 seconds, a first induction fan 14 provided on the downstream side of the constant temperature chamber 2 in order to maintain the system downstream of the plasma decomposition apparatus 1 at a pressure lower than atmospheric pressure; The second induction fan 15 is provided.

  Furthermore, the invention according to claim 5 is the treatment apparatus for contaminants contaminated with polychlorinated biphenyl according to claim 4, wherein the flow path to the plasma decomposition furnace 8 upstream from the second induction fan 15 is more than atmospheric pressure. It is configured to be held at a low pressure. Furthermore, the invention described in claim 6 is a treatment apparatus for contaminants contaminated with polychlorinated biphenyl according to claim 4 or 5, wherein a part of the flow path in the system on the downstream side of the plasma decomposition apparatus 1 is branched to produce plasma. A circulation channel 16 is formed in which exhaust gas can be circulated so as to control the pressure in the furnace of the decomposition apparatus 1 to a constant pressure lower than the atmospheric pressure.

  As described above, in the present invention, after the pollutant contaminated with polychlorinated biphenyl is decomposed by the plasma decomposition apparatus 1, the exhaust generated by the decomposition of the contaminant is maintained at a temperature of 1100 ° C to 1400 ° C. Since the treatment is performed by staying in the chamber 2 for 1 to 5 seconds, the PCB in the contaminant which is the object to be treated can be completely decomposed by the plasma decomposition apparatus. Even if the PCB is decomposed by the plasma decomposition apparatus, even if the substance that is volatilized while undergoing thermal polymerization and being transformed into a harmful organic substance (for example, dioxins) having a higher degree of contamination remains in the exhaust, By staying at 1200 ° C. for 2 seconds in a constant temperature chamber in the next step, there is an effect that the remaining harmful organic substance can be more completely decomposed.

  As a result, even if the properties of the processing object contaminated with PCB are not constant, these processing objects can be made harmless by plasma irradiation collectively, and the temperature and residence time in the constant temperature chamber By automatically controlling this, there is an effect that harmless exhaust gas can be supplied to the subsequent stage regardless of the PCB contamination of any composition.

  In addition, when the high-temperature exhaust discharged from the plasma decomposition apparatus through the constant temperature chamber is rapidly cooled by the temperature reducing tower, there is an effect that dioxins are not re-synthesized in the exhaust. Furthermore, by removing dust with a bag filter, it is possible to more completely prevent dioxins from being re-synthesized, and to obtain a desalting effect and the like.

  Furthermore, when a catalytic reaction tower to which ammonia is added is provided, it is possible to suitably decompose NOx in the exhaust gas generated by the decomposition of contaminants in the plasma decomposition apparatus, and even when a minute amount of dioxins is present, These can be removed by adsorption. Furthermore, by providing an activated carbon tank as a safety net, even if toxic organic substances remain in the exhaust, it can be adsorbed by the activated carbon in the activated carbon tank, so that a very clean and harmless exhaust can be discharged.

  Further, in the system on the downstream side of the plasma decomposing apparatus, the flow path to the plasma decomposing apparatus on the upstream side of the second attracting fan is made higher than the atmospheric pressure by the two attracting fans of the first attracting fan and the second attracting fan. By maintaining the pressure at a low pressure, there is an effect that PCB leakage to the outside of the system in the middle of the flow path can be prevented. Furthermore, the flow in the system on the downstream side of the plasma decomposition apparatus is partially branched to form a circulation flow path, and the exhaust gas is circulated through the circulation flow path, so that the pressure in each apparatus such as the plasma decomposition apparatus is changed to atmospheric pressure. By controlling the pressure to a lower constant pressure, it is possible to more reliably prevent fluctuations in the pressure in the apparatus, and it becomes easier to control the system to a constant pressure lower than the atmospheric pressure. There is an effect that leakage of harmful organic substances and the like can be prevented more reliably.

1 is a schematic block diagram showing a contaminant treatment apparatus as one embodiment. The schematic sectional drawing of a plasma decomposing apparatus.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, the PCB contaminant treatment apparatus of the present embodiment includes a plasma decomposition apparatus 1, a constant temperature chamber 2, a temperature-decreasing tower 3, a first bag filter 4, a second bag filter 5, A catalytic reaction tower 6 and an activated carbon tank 7 are provided.

  The plasma decomposition apparatus 1 includes a plasma decomposition furnace 8 and a pail can input chamber 9. The pail can chamber 9 is a chamber for directly loading the pail can 13 filled with PCB contaminants, and is provided adjacent to the plasma decomposition furnace 8 so that the pail can can be transferred to the plasma decomposition furnace 8. Yes. The plasma decomposition furnace 8 is a furnace for generating a plasma arc, and a plasma torch 9 is mounted on the ceiling of the plasma decomposition furnace 8 so as to be inserted into the furnace from the outside. The plasma torch 9 is generally a non-transition type that has an anode and a cathode in the torch body, and a transition type that has only the anode in the torch body and uses the object to be melted as the cathode. In this embodiment, a non-transfer type plasma torch is used.

  This is because the non-transferred plasma torch can be used more effectively than the transfer type if the object to be processed includes an electrically insulating material such as concrete waste. In this non-migration type plasma torch, the gas between the anode and the cathode is energized. By sending the gas continuously, a very high temperature gas can be generated. The plasma torch 9 is configured to be freely movable in three degrees of freedom. In addition, the plasma decomposition furnace 8 can be provided with a camera for observing the inside of the furnace as necessary, and the plasma torch 9 can be moved according to the decomposition state of the non-processed material in the furnace. It is also possible to do. Thereby, it is possible to selectively irradiate an unprocessed unprocessed object with plasma. Further, the plasma decomposition furnace 8 can be configured to tilt.

  The inside of the plasma decomposition furnace 8 is maintained at about 1400 ° C., and the PCB is decomposed in the plasma decomposition furnace 8. However, the temperature of the irradiated plasma is 15000 degrees or more. One or a plurality of slag discharge containers 11 are provided in the lower part of the plasma decomposition furnace 8, and the slag discharge containers 11 containing the slag 12 are configured to be discharged to the outside of the plasma decomposition furnace 8. ing. This slag 12 is produced by melting incombustible material such as earth and sand, metal, concrete waste, etc., among the PCB contaminants filled in the pail can 13 and is plasma-decomposed in a solidified state from the molten state. It will be discharged outside the furnace 8. The solidified slag 12 is a mixture of silica, alumina, calcium oxide and the like.

  The constant temperature chamber 2 is a chamber for supplying exhaust gas such as combustion gas generated in the plasma decomposition furnace 8 of the plasma decomposition apparatus 1 and water vapor, and the PCB is decomposed in the plasma decomposition furnace 8. This is for decomposing the remaining harmful organic substances when those which are volatilized while being transformed into harmful organic substances such as dioxins having a high degree of pollution remain in the exhaust. The constant temperature chamber 2 is maintained at 1200 ° C. by a natural gas burner, and the supplied exhaust gas is configured to stay in the constant temperature chamber 2 for 2 seconds. Here, “retain for 2 seconds” means that the average flow velocity of the gas (exhaust gas) flowing from the inlet portion to the outlet portion of the constant temperature chamber 2 is 2 seconds. As a method of maintaining the inside of the constant temperature chamber 2 at 1200 ° C., a method of performing feedback control in which a temperature measuring device is attached to the outlet of the constant temperature chamber and the amount of burning of the burner is adjusted according to the temperature indication value can be considered.

  The temperature-decreasing tower 3 is for cooling the exhaust gas supplied from the constant-temperature chamber 2, and is prevented from recombining dioxins by being cooled. Water and air are used for this rapid cooling in a short time. The outlet temperature of the temperature reducing tower 3 is preferably 140 ° C. to 260 ° C., and the water content in the exhaust gas at the outlet is preferably 40% by volume or less.

  The first bag filter 4 and the second bag filter 5 are devices for collecting dust, and the first bag filter 4 absorbs and removes a trace amount of harmful organic substances such as dioxins by blowing powdered activated carbon. It is. The second bag filter 5 adds slaked lime to adsorb and remove acidic gas such as HCl in the exhaust gas, and has not only dust collection but also a desalting function.

  The catalytic reaction tower 6 decomposes dioxins and the like that can be re-synthesized, and also decomposes NOx. The catalytic reaction tower 6 is formed by kneading a metal that can be a catalyst such as titanium, vanadium, and nickel into ceramic. 6 is provided. The activated carbon tank 7 has a function as a so-called safety net that adsorbs harmful organic substances in the final stage of the system, and is filled with activated carbon.

A first induction fan 14 is provided in the flow path between the second bag filter 5 and the catalytic reaction tower 6, and a second induction fan 15 is provided in the flow path downstream of the activated carbon tank 7. ing. Further, a circulation flow path 16 is provided for returning the exhaust gas from the flow path between the first induction fan 14 and the catalytic reaction tower 6 to the flow path between the temperature reducing tower 3 and the first bag filter 4 for circulation. It has been. An on-line analyzer 17 that analyzes exhaust gas such as NOx, HCl, CO, CO ₂ , and O ₂ is provided in the flow path on the downstream side of the second induction fan 15.

  Next, a processing method for detoxifying PCB contaminants using the PCB contaminant processing apparatus having the above-described configuration will be described. In the following, for the sake of illustration, a case where a pail can is used as a container for PCB contamination will be described. However, even when a larger container such as a drum can is used, the same processing method can be used.

  First, a pail can filled with PCB contaminants, which are processing objects, is put into a pail can loading chamber 9 of the plasma decomposition apparatus 1. In this case, the pail can is hung by a hanging tool or mechanically loaded by a pusher. The bottom surface of the pail can charging chamber 9 is formed in a taper shape as shown in FIG. 2, and thus the pail can charged is transferred to the plasma decomposition furnace 8 along the inclination of the taper portion.

  The pail can 13 transferred to the plasma decomposition furnace 8 is melted by a plasma arc generated from a plasma torch 9 attached to the ceiling of the plasma decomposition furnace 8. In the plasma decomposition furnace 8, molten slag is stored to some extent to form a slag bath 19. Then, the pail cans 13 sequentially introduced from the pail can introduction chamber 9 into the plasma decomposition furnace 8 are immersed in the slag bath 19 in the plasma decomposition furnace 8, and the heat of the slag bath is transmitted and dissolved.

  Accordingly, the portion immersed in the slag bath 19 of the charged pail can 13 is dissolved by the heat of the slag bath 19, and the portion not immersed in the slag bath 19 is dissolved by the high temperature gas generated in the plasma torch 9. The can 13 is efficiently dissolved.

  Incombustible materials such as earth and sand, metal, and concrete are melted as described above to form the slag 12, stored in the slag discharge container 11, and discharged to the outside of the plasma decomposition furnace 8. The slag bath is maintained at 1300 degrees or more, and the slag accumulated in the furnace is accommodated in the slag discharge container 11 as described above by appropriately tilting the furnace.

  On the other hand, the exhaust gas combusted in the plasma decomposition furnace 8 is supplied to the constant temperature chamber 2 of the next process together with water vapor. The inside of the constant temperature chamber 2 is maintained at 1200 ° C. as described above, and the supplied exhaust gas is retained in the constant temperature chamber 2 for 2 seconds and then discharged from the constant temperature chamber 2.

  In this case, the PCB contained in the contaminant that is the object to be treated is completely decomposed in the plasma decomposition furnace 8 maintained at a high temperature. Even if the PCB was decomposed in the plasma decomposition furnace 8, even if there is something in the exhaust gas that has undergone thermal polymerization and is transformed into a toxic organic substance (for example, dioxins) with a higher degree of contamination, it is volatilized. This harmful organic substance is completely decomposed by staying in the constant temperature chamber 2 maintained at 1200 ° C. for 2 seconds as described above.

  Next, the exhaust gas that has passed through the constant temperature chamber 2 is further supplied to the temperature reducing tower 3 and cooled with water and air. Since water is sprayed in the form of a mist, it evaporates instantaneously and does not leak from the temperature reducing tower 3. The exhaust gas thus supplied to the temperature reducing tower 3 is cooled with water and air, thereby preventing dioxins from being re-synthesized. That is, if the exhaust gas after PCB decomposition is present in an atmosphere in which the temperature is gradually changed within a temperature range of 200 ° C. to 500 ° C., there is a high possibility that dioxins are re-synthesized. On the other hand, when the exhaust gas after being treated at a high temperature of 1100 ° C. or higher in the plasma decomposition furnace 8 or the constant temperature chamber 2 as described above is cooled down to 200 ° C. in the temperature reducing tower 3, dioxins are re-synthesized. This is almost completely prevented.

  The cooled exhaust gas is supplied to the first bag filter 4 and powdered activated carbon is blown into it. As described above, the PCB should be completely decomposed in the plasma decomposition furnace 8 and the recombination of dioxins should be prevented in the temperature-decreasing tower 3, but a trace amount of harmful organic substances such as dioxin is supposed to be used. Even if the kind is synthesized, these harmful organic substances are adsorbed by the activated carbon blown into the first bag filter 4 and are removed.

The exhaust gas after passing through the first bag filter 4 is supplied to the second bag filter 5. In the second bag filter 5, slaked lime is added and an acidic gas such as HCl is adsorbed and removed. That is, HCl, SOx, etc. are generated in the exhaust gas processed in the plasma decomposition apparatus 1, the constant temperature chamber 2, etc., but the HCl, SOx, etc. are reacted with slaked lime to be converted from exhaust gas to dust. It is. In the case of HCl, the following reaction is assumed.
Ca (OH) ₂ + 2HCl → CaCl ₂ + 2H ₂ O

The exhaust gas after passing through the second bag filter 5 is supplied to the catalytic reaction tower 6. Ammonia is blown into the catalytic reaction tower 6 to decompose NOx. That is, since nitrogen exhaust is present in the plasma decomposition furnace 8, there is a possibility that NOx is generated when passing through the constant temperature chamber 2, the temperature reducing tower 3, the first bag filter 4, and the second bag filter 5 thereafter. However, NOx is suitably decomposed by blowing ammonia in the catalytic reaction tower 6. Even if a small amount of dioxins is re-synthesized and not removed by the first bag filter 4, the dioxins are also decomposed in the catalytic reaction tower 6.
The NOx decomposition reaction is assumed as follows.
NO ₂ + NO + 2NH ₃ + O ₂ → 2N ₂ + 3H ₂ O

  The exhaust gas after passing through the catalytic reaction tower 6 is further supplied to the activated carbon tank 7. The activated carbon tank 7 functions as a safety net when harmful organic substances remain in the final stage of the system as described above, and a trace amount of harmful organic substances remain or a small amount of dioxins. Even if it is re-synthesized, since it is adsorbed in the activated carbon tank 7, even trace amounts of harmful organic substances and dioxins are not inadvertently discharged out of the system. Thus, the activated carbon tank 7 as a safety net can adsorb and remove harmful components in the unlikely event.

It should be noted that components such as NOx, HCl, CO, CO ₂ , and O ₂ in the exhaust discharged outside the system are analyzed by the online analyzer 17. Further, a first induction fan 14 is provided in the flow path between the second bag filter 5 and the catalytic reaction tower 6, and a second induction fan 15 is provided in the flow path downstream of the activated carbon tank 7. Therefore, the system in the upstream side of the second induction fan 15 can be maintained at a negative pressure by the two induction fans 14 and 15. More specifically, the flow path to the plasma decomposition furnace 8 upstream of the second induction fan 11 is set to a pressure lower than atmospheric pressure.

  This is because if there is a portion that is at a pressure higher than atmospheric pressure in the flow path on the upstream side of the second induction fan 15, there is a possibility that PCB and harmful organic substances will leak from that portion. For example, if the flow path between the first attracting fan 14 and the second attracting fan 15 is set to a pressure higher than the atmospheric pressure, harmful organic substances such as dioxins may leak from the catalytic reaction tower 6 or the like. is there. For this purpose, even if the pressure in the downstream flow path of the second bag filter 5 is increased by the first induction fan 10, it is necessary to maintain the pressure lower than the atmospheric pressure. On the other hand, in order to discharge the plasma gas to the outside of the system, the vicinity of the discharge part needs to be maintained at a pressure higher than the atmospheric pressure. For this reason, the downstream side of the second induction fan 11 is set to a pressure higher than the atmospheric pressure.

  Next, a circulation flow path 16 for returning exhaust gas from the flow path between the first induction fan 14 and the catalytic reaction tower 6 to the flow path between the temperature reducing tower 3 and the first bag filter 4 is provided. Since it is provided, the inside of the plasma decomposition furnace 8, the constant temperature chamber 2, the temperature reducing tower 3, the first bag filter 4, the second bag filter 5, etc. can be adjusted by adjusting the flow rate of the exhaust gas flowing through the circulation channel 16. As a result, the pressure in the system can be kept constant. That is, since the pail can which is a processing object is put into the plasma decomposition furnace 8 from the pail can input chamber 9 at once, the pressure fluctuates inside the plasma decomposition furnace 8, the constant temperature chamber 2, the temperature reducing tower 3, and the like. Is likely to occur. However, by providing the circulation flow path 16 as described above, the circulation flow rate of the exhaust gas circulating through the circulation flow path 16 is adjusted, so that the plasma decomposition furnace 8, the constant temperature chamber 2, the temperature reduction tower 3, the first bug. It is possible to suppress pressure fluctuations inside the filter 4 and the second bag filter 5 as much as possible.

  As described above, in the present embodiment, the PCB in the contaminant that is the object to be processed can be completely decomposed by the plasma decomposition apparatus 1, but the PCB is decomposed but is subjected to thermal polymerization. Even if volatile substances that have been transformed into harmful organic substances (for example, dioxins) with a high degree of pollution remain in the exhaust gas, they remain by being retained at 1200 ° C. for 2 seconds in the constant temperature chamber 2 of the next process. It can decompose harmful organic substances. Moreover, since the high temperature exhaust discharged from the plasma decomposition apparatus 1 through the constant temperature chamber 2 is rapidly cooled by the temperature reducing tower 3, dioxins are not re-synthesized. Moreover, even if the recombination of dioxins cannot be completely prevented by the temperature-decreasing tower 3, the dust is suitably removed by the subsequent first bag filter 4 and the second bag filter 5, so that the recombination of dioxins can be further improved. Completely prevented. Furthermore, harmful organic substances and dioxins that could not be decomposed by the plasma decomposition apparatus 1, the constant temperature chamber 2, the temperature reducing tower 3, the first bag filter 4, the second bag filter 5, and the catalytic reaction tower 6 are used as a safety net. Therefore, the entire system can discharge harmless and very clean exhaust gas.

  In addition, by providing two induction fans, the first induction fan 14 and the second induction fan 15, and maintaining the pressure in the downstream flow path of the second bag filter 5 at a pressure lower than the atmospheric pressure, the entire system is increased. It can be maintained at a pressure lower than the atmospheric pressure (negative pressure), thereby preventing leakage of PCB and harmful organic substances from the middle part of the system. In addition, a circulation passage 16 is provided for returning and circulating the exhaust gas from the passage between the first induction fan 14 and the catalytic reaction tower 6 to the passage between the temperature reducing tower 3 and the first bag filter 4. By adjusting the flow rate of the exhaust gas flowing through the circulation channel 16, the pressure in the plasma decomposition furnace 8, the constant temperature chamber 2, the temperature reducing tower 3, the first bag filter 4, the second bag filter 5 and the like, and thus the pressure in the system Can be kept constant, and fluctuations in pressure due to the introduction of a pail can as a processing object to the plasma decomposition furnace 8 can be prevented as much as possible.

  In the above embodiment, since the high-temperature exhaust gas is rapidly cooled by the temperature reducing tower 3, the above-described preferable effects are obtained. However, the provision of the temperature reducing tower 3 is not an essential condition for the present invention. . In the present embodiment, since the two bug filters of the first bug filter 4 and the second bug filter 5 are provided, the above-described preferable effect is obtained. However, the first bug filter 4 and the second bug filter 5 are provided. It is not an essential condition for the present invention. Furthermore, in this embodiment, the above-mentioned preferable effects were obtained by providing the catalytic reaction tower 6 and the activated carbon tank 7, but it is also essential to provide these catalytic reaction tower 6 and the activated carbon tank 7 in the present invention. is not.

  Therefore, an apparatus including only the plasma decomposition apparatus 1 and the constant temperature chamber 2 is included in the scope of the present invention. In addition to the plasma decomposition apparatus 1 and the constant temperature chamber 2, an apparatus including only the temperature reducing tower 3 and the bag filter is provided. Is also included in the scope of the present invention, and in addition to the plasma decomposition apparatus 1 and the constant temperature chamber 2, an apparatus provided with only the catalytic reaction tower 6 and the activated carbon tank 7 is also included in the scope of the present invention. In short, it is only necessary that the constant temperature chamber 2 as described above is provided in the subsequent stage (downstream side) of the plasma decomposition apparatus 1.

  Furthermore, in the said embodiment, although the temperature in the constant temperature chamber 2 was 1200 degreeC and the residence time was 2 second, the temperature and residence time in the constant temperature chamber 2 are not limited to this embodiment. In short, the temperature in the constant temperature chamber 2 may be 1100 ° C. to 1400 ° C., and the residence time may be 1 to 5 seconds.

  The temperature is set to 1100 ° C. to 1400 ° C. If the temperature is lower than 1100 ° C., even if the PCB can be decomposed by the plasma decomposition apparatus 1 that performs high-temperature processing, harmful organic substances newly generated by decomposition and modification of the PCB are removed. The original purpose of the constant temperature chamber for decomposition cannot be achieved, and if it exceeds 1400 ° C., the temperature in the plasma decomposition apparatus 1 is higher than that in the plasma decomposition apparatus 1. This is because the original purpose of detoxifying the remaining harmful organic substances is lost. From this viewpoint, the temperature in the constant temperature chamber 2 is more preferably 1100 ° C. to 1300 ° C., and further preferably 1100 to 1250 ° C.

  On the other hand, if the residence time is set to 1 to 5 seconds, if it is less than 1 second, the remaining harmful organic substances may not be completely decomposed. This is because the original purpose of processing organic substances quickly in a short time for the purpose of supplementing the plasma decomposition apparatus is lost. From this point of view, the residence time in the constant temperature chamber 2 is more preferably 1.5 to 3 seconds.

  Furthermore, in the said embodiment, although the pail can filled with various contaminants was processed object, a processed object is not limited to it, All kinds of contaminants can be used as processed objects.

  Therefore, the structure of the plasma decomposing apparatus 1 is not limited to the structure having the plasma decomposing furnace 8 and the pail can charging chamber 9 as in the present embodiment, but has a structure including only the plasma decomposing furnace. May be. Such a plasma decomposition apparatus 1 is basically provided with a furnace body as in the above-described embodiment, and is provided with a plasma torch 9 as described above. "Plasma decomposition apparatus" does not ask whether these furnace bodies and plasma torches are provided, but means to include a wide range of apparatuses that decompose plasma by generating plasma.

  The present invention can be widely applied to the detoxification of various contaminants such as sludge, waste, pressure-sensitive paper, fluorescent light ballast, transformer, and condenser contaminated with polychlorinated biphenyl.

DESCRIPTION OF SYMBOLS 1 Plasma decomposition apparatus 2 Constant temperature chamber 3 Temperature reduction tower 4 1st bag filter 5 2nd bag filter 6 Catalytic reaction tower 7 Activated carbon tank 8 Plasma decomposition furnace 14 1st induction fan 15 2nd induction fan 16 Circulation flow path

Claims (6)

  After the pollutant contaminated with polychlorinated biphenyl is decomposed by the plasma decomposition apparatus (1), the exhaust generated by the decomposition of the contaminant is stored in the constant temperature chamber (2) maintained at a temperature of 1100 ° C to 1400 ° C. The system is allowed to stay for 5 seconds, and the system on the downstream side of the plasma decomposition apparatus (1) is reduced to a pressure lower than the atmospheric pressure by the two induction fans, the first induction fan (14) and the second induction fan (15). A method for treating a contaminant contaminated with polychlorinated biphenyl, which is characterized by holding.   The method for treating contaminants contaminated with polychlorinated biphenyl according to claim 1, wherein the flow path to the plasma decomposition furnace (8) upstream of the second induction fan (15) is maintained at a pressure lower than atmospheric pressure.   The flow path in the system on the downstream side of the plasma decomposition apparatus (1) is partially branched to form a circulation flow path, and the exhaust gas is circulated through the circulation flow path, thereby reducing the pressure in the furnace of the plasma decomposition apparatus (1). The method for treating a contaminant contaminated with polychlorinated biphenyl according to claim 1 or 2, wherein the pressure is controlled to a constant pressure lower than the atmospheric pressure.   A plasma decomposition apparatus (1) for decomposing contaminants contaminated with polychlorinated biphenyl, and a constant temperature chamber (2) in which exhaust gas generated from the plasma decomposition apparatus (1) is retained at a temperature of 1100 ° C. to 1400 ° C. for 1 to 5 seconds. ), And a first induction fan (14) and a second induction fan provided on the downstream side of the constant temperature chamber (2) in order to keep the system downstream of the plasma decomposition apparatus (1) at a pressure lower than atmospheric pressure. An apparatus for treating contaminants contaminated with polychlorinated biphenyl, comprising an induction fan (15).   5. The polychlorinated biphenyl according to claim 4, wherein the flow path from the second induction fan (15) to the plasma decomposition furnace (8) upstream is maintained at a pressure lower than atmospheric pressure. Contaminant treatment equipment.   The exhaust gas can be circulated so as to control a pressure in the furnace of the plasma decomposition apparatus (1) to a constant pressure lower than the atmospheric pressure by partially branching a flow path in the system on the downstream side of the plasma decomposition apparatus (1). The apparatus for treating contaminants contaminated with polychlorinated biphenyl according to claim 4 or 5, wherein a circulation channel (16) is formed.

Images