JP2007296415A - Treatment method of polybiphenyl chloride pollutant and treatment system therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a treatment method of a polybiphenyl chrolide pollutant suppressing the resynthesis of polybiphenyl chloride, and a treatment system therefor. <P>SOLUTION: The treatment system of the polybiphenyl chloride pollutant has a plasma decomposition furnace 12 in which a polybiphenyl chloride pollutant 11 is charged and the plasma torch 13 provided to the plasma decomposition furnace 12 to emit a plasma arc of a high temperature state. The polybiphenyl chloride pollutant 11 is charged in the plasma decomposition furnace 12 and an oxygen-containing gas is supplied into the plasma decomposition furnace 12 to detoxify and stabilize the polybiphenyl chloride pollutant 11. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a method and a treatment system for detoxifying polychlorinated biphenyl contaminants such as sludge, waste, pressure-sensitive copying paper, fluorescent ballasts, or waste activated carbon used for local exhaust purification. .

Conventionally, polychlorinated biphenyl (PCB) is chemically stable, resistant to heat, and excellent in insulation, so it is mainly used as insulation oil for transformers and capacitors, and heat medium oil for various factories. Widely used. However, since PCBs are likely to accumulate in natural products and living organisms, their use is severely limited. Of course, PCBs themselves, for example, sludge, waste, pressure-sensitive copying paper, fluorescent ballasts, or local exhaust purification. There is a need for a method of detoxifying contaminants (PCB contaminants) contaminated with PCBs such as waste activated carbon used for industrial purposes.
Therefore, as a method for treating PCB, (1) a high temperature incineration method in which residence is performed at 1100 ° C. or more for 2 seconds or more, (2) dechlorination decomposition method in which chlorine is desorbed from PCB by an alkali agent such as metallic sodium, (3) A photodecomposition method using ultraviolet rays and a catalyst, and (4) a plasma decomposition method for decomposing PCB by a plasma arc (for example, see Patent Document 1) have been developed.

JP 2004-121801 A

However, in the high-temperature incineration method, there is a problem that PCB may not be completely decomposed and there is a risk that PCB or a more toxic dioxin is generated from a decomposition product of PCB. Further, in the dechlorination decomposition method and the photolysis method, since chlorine is only desorbed from the PCB, there is a problem that the desorbed chlorine may recombine with biphenyl and a new PCB may be generated. Furthermore, in the high temperature incineration method, the dechlorination decomposition method, and the photodecomposition method, there is a problem that the contaminated material to which the PCB adheres must be treated separately from the PCB.

Further, in the plasma decomposition method, it is possible to treat the entire metal container that stores PCB contaminants. However, undecomposed PCB and PCB decomposition products contained in the exhaust gas generated when the PCB contaminants are plasma decomposed are 1100-1000. A constant temperature chamber that holds at 1400 ° C. for 1 to 5 seconds and completely decomposes, and a temperature-decreasing tower that rapidly cools the exhaust gas so that PCBs or more toxic dioxins are not synthesized from the exhaust gas in which PCB is completely decomposed It was necessary. Furthermore, since the waste activated carbon is thermally stable, there is also a problem that the processing speed does not increase even with the plasma melting method.

This invention is made | formed in view of this situation, and it aims at providing the processing method and its processing system of the polychlorinated biphenyl contaminant which suppressed resynthesis of polychlorinated biphenyl.

The method for treating polychlorinated biphenyl contaminants according to the first aspect of the present invention, in which a polychlorinated biphenyl contaminant is placed in a plasma decomposition furnace, and a high-temperature plasma arc generated from a plasma torch provided in the plasma decomposition furnace In the method for treating polychlorinated biphenyl contaminants, which thermally decomposes the polychlorinated biphenyl,
An oxygen-containing gas is supplied into the plasma decomposition furnace to stabilize the polychlorinated biphenyl contaminants harmlessly.

Examples of PCB contaminants include sludge, waste, ballast, pressure-sensitive copying paper, rough demolition products of PCB-containing electrical equipment such as transformer cores and capacitor elements, and waste activated carbon used for local exhaust purification. Usually, these are hermetically stored in metal containers (eg, drums). In the present invention, the PCB contamination includes waste PCB, waste oil containing PCB, waste acid, waste alkali, and the like. PCBs may also contain dioxins including highly toxic coplanar PCBs, which are by-products.

For example, a metal container enclosing a PCB contaminant is placed in a plasma decomposition furnace, and an oxygen-containing gas (for example, air or oxygen) is further supplied into the plasma decomposition furnace. A plasma arc of 15000 ° C. or higher is generated, and PCB is instantaneously decomposed to an atomic level, and the inside of the plasma decomposition furnace becomes about 1100 to 1400 ° C. by the heat of the plasma arc, and the PCB can be thermally decomposed by this heat. . At this time, dioxins contained in the PCB contaminant are also thermally decomposed. These decomposition products (eg, dioxin precursors, benzene, and chlorides) are oxidized by oxygen in the oxygen-containing gas to become stable substances, such as carbon dioxide, water, and hydrogen chloride, and are rendered harmless. Is done. The plasma arc is plasma generated by plasma discharge. As the oxygen-containing gas, oxygen concentration is 20% by volume or more, that is, air or a gas containing oxygen in air or more is used.

In the method for treating a polychlorinated biphenyl contaminant according to the first invention, an oxygen-containing gas may be used as the plasma arc gas.
In the method for treating a polychlorinated biphenyl contaminant according to the first invention, it is preferable that the oxygen-containing gas is oxygen gas (pure oxygen), and the inside of the plasma decomposition furnace is substantially in an oxygen atmosphere.

A method for treating polychlorinated biphenyl contaminants according to the second aspect of the present invention, in which a polychlorinated biphenyl contaminant is placed in a plasma decomposition furnace, and a high-temperature plasma arc generated from a plasma torch provided in the plasma decomposition furnace A thermostatic chamber in which the polychlorinated biphenyl is thermally decomposed by the above, and undecomposed polychlorinated biphenyl and polychlorinated biphenyl decomposition products contained in the exhaust gas generated at that time are connected to the plasma decomposition furnace via a duct. In a method for treating polychlorinated biphenyl contaminants which are completely decomposed by being held at 1100-1400 ° C. for 1-5 seconds in
An oxygen-containing gas is supplied into one or both of the constant temperature chamber and the duct to stabilize the polychlorinated biphenyl contaminants harmlessly.

Undecomposed PCB and PCB decomposition products contained in the exhaust gas generated when plasma decomposing PCB contaminants are completely decomposed by holding at 1100 to 1400 ° C. for 1 to 5 seconds in a constant temperature chamber, Oxidized by oxygen in the oxygen-containing gas, becomes stable substances such as carbon dioxide, water, and hydrogen chloride, and is rendered harmless. Therefore, normally, a temperature reducing tower arranged at the rear stage of the constant temperature chamber is not necessary.

In the method for treating polychlorinated biphenyl contaminants according to the second invention, an oxygen-containing gas may be further supplied into the plasma decomposition furnace.
In the method for treating a polychlorinated biphenyl contaminant according to the second invention, the oxygen-containing gas is preferably oxygen gas.

A polychlorinated biphenyl contaminant treatment system according to a third aspect of the present invention includes a plasma decomposition furnace for containing a polychlorinated biphenyl contaminant, and a plasma torch that is provided in the plasma decomposition furnace and generates a high-temperature plasma arc. Then, an oxygen-containing gas is supplied into the plasma decomposition furnace.
Here, as the oxygen-containing gas, oxygen concentration of 20% by volume or more, that is, air or a gas containing oxygen in excess of air can be used, and oxygen gas (pure oxygen) is particularly preferable.
In the polychlorinated biphenyl contaminant treatment system according to a third aspect of the present invention, the oxygen-containing gas may be directly supplied into the plasma decomposition furnace.

In the polychlorinated biphenyl contaminant treatment system according to a third aspect of the present invention, a sealed container surrounding the plasma decomposition furnace is disposed outside the plasma decomposition furnace, and the inside of the closed container is at a positive pressure, and the plasma decomposition furnace The inside becomes a negative pressure, and the oxygen-containing gas may be filled in the sealed container.
In the polychlorinated biphenyl contaminant treatment system according to the third invention, the oxygen-containing gas may be supplied into the plasma decomposition furnace via the plasma torch.
A part or all of the oxygen-containing gas supplied into the plasma decomposition furnace is supplied to the plasma torch.

A system for treating polychlorinated biphenyl contaminants according to a fourth aspect of the present invention is a plasma decomposition furnace for containing polychlorinated biphenyl contaminants, a plasma torch that is provided in the plasma decomposition furnace and generates a high-temperature plasma arc, and the plasma A constant temperature chamber connected to the cracking furnace via a duct and holding the exhaust from the plasma decomposition furnace at 1100 to 1400 ° C. for 1 to 5 seconds, and supplying an oxygen-containing gas into the constant temperature chamber.

In the polychlorinated biphenyl contaminant treatment system according to a fourth aspect of the invention, the oxygen-containing gas may be supplied to one or both of the constant temperature chamber and the duct.
In the polychlorinated biphenyl contaminant treatment system according to a fourth aspect of the present invention, the oxygen-containing gas may be further supplied into the plasma decomposition furnace.

In the method for treating polychlorinated biphenyl contaminants according to claims 1 to 3, the polychlorinated biphenyl contaminant is placed in a plasma decomposition furnace, an oxygen-containing gas is supplied, and a high-temperature plasma arc is generated from the plasma torch. Therefore, polychlorinated biphenyl and its decomposition product can be oxidized to suppress resynthesis of polychlorinated biphenyl. In addition, decomposition products of dioxins, which are by-products of polychlorinated biphenyls, such as dioxin precursors, benzene, and chlorides are also oxidized, so that resynthesis of dioxins can also be suppressed. Furthermore, normally, when polychlorinated biphenyl is decomposed in the air, carbon monoxide and carbon are produced, but can be oxidized to carbon dioxide by oxygen in the oxygen-containing gas supplied into the plasma decomposition furnace. Carbon generation is suppressed. Furthermore, thermally activated waste activated carbon has the effect of increasing the reaction rate from carbon monoxide to carbon dioxide by supplying an oxygen-containing gas.

In particular, in the method for treating a polychlorinated biphenyl contaminant according to claim 2, since an oxygen-containing gas is used as a plasma arc gas, oxygen plasma can be generated more efficiently.
In the method for treating a polychlorinated biphenyl contaminant according to claim 3, since the oxygen-containing gas is oxygen gas and the inside of the plasma decomposition furnace is substantially in an oxygen atmosphere, generation of nitrogen oxides can be suppressed. .

In the method for treating polychlorinated biphenyl contaminants according to claims 4 to 6, the polychlorinated biphenyl contaminant is put in a plasma decomposition furnace, the polychlorinated biphenyl is thermally decomposed, and contained in the exhaust gas generated at that time. Undecomposed polychlorinated biphenyl and polychlorinated biphenyl degradation products are completely decomposed by holding at 1100 to 1400 ° C. for 1 to 5 seconds in a constant temperature chamber, and in one or both of the constant temperature chamber and the duct. Since the oxygen-containing gas is supplied to stabilize the polychlorinated biphenyl contaminants harmlessly, the polychlorinated biphenyl and its decomposition products can be oxidized to suppress the resynthesis of the polychlorinated biphenyl.

In particular, in the method for treating a polychlorinated biphenyl contaminant according to claim 5, since the oxygen-containing gas is further supplied into the plasma decomposition furnace, the polychlorinated biphenyl and the decomposition product thereof can be oxidized in the plasma decomposition furnace. And can treat polychlorinated biphenyl contaminants more efficiently.
In the method for treating a polychlorinated biphenyl contaminant according to claim 6, since the oxygen-containing gas is an oxygen gas, generation of nitrogen oxides can be suppressed.

In the polychlorinated biphenyl contaminant treatment system according to any one of claims 7 to 10, a plasma decomposition furnace for containing the polychlorinated biphenyl contaminant, and a plasma torch that is provided in the plasma decomposition furnace and generates a high-temperature plasma arc. And supplying an oxygen-containing gas into the plasma decomposition furnace, the inside of the plasma decomposition furnace becomes an oxygen atmosphere, polychlorinated biphenyl and its decomposition products are oxidized, and resynthesis of polychlorinated biphenyl can be suppressed. Moreover, resynthesis of dioxins, which are by-products of polychlorinated biphenyl, can also be suppressed.
In particular, in the polychlorinated biphenyl contaminant treatment system according to the eighth aspect, the oxygen-containing gas is directly supplied into the plasma decomposition furnace, so that the plasma decomposition furnace can have a simple structure.

In the polychlorinated biphenyl contaminant treatment system according to claim 9, a sealed container surrounding the plasma decomposition furnace is disposed outside the plasma decomposition furnace, and the inside of the sealed container has a positive pressure and the inside of the plasma decomposition furnace has a negative pressure. Moreover, since the sealed container is filled with the oxygen-containing gas, it is easy to supply the oxygen-containing gas into the plasma decomposition furnace.
In the polychlorinated biphenyl contaminant treatment system according to the tenth aspect, the oxygen-containing gas is supplied into the plasma decomposition furnace via the plasma torch, so that oxygen plasma can be generated more efficiently.

In the polychlorinated biphenyl contaminant treatment system according to any one of claims 11 to 13, a plasma decomposition furnace containing the polychlorinated biphenyl contaminant, a plasma torch provided in the plasma decomposition furnace and generating a high-temperature plasma arc; The plasma decomposition furnace is connected to the plasma decomposition furnace via a duct and holds the exhaust from the plasma decomposition furnace at 1100 to 1400 ° C. for 1 to 5 seconds, and the oxygen-containing gas is supplied into the constant temperature chamber. Oxidation of undecomposed polychlorinated biphenyl and polychlorinated biphenyl degradation products contained in the exhaust gas generated when pyrolyzing polychlorinated biphenyl in the furnace in a constant temperature chamber suppresses resynthesis of polychlorinated biphenyl. be able to. Moreover, resynthesis of dioxins, which are by-products of polychlorinated biphenyl, can also be suppressed. Furthermore, it is not necessary to arrange a temperature reducing tower after the constant temperature chamber.

In particular, in the polychlorinated biphenyl contaminant treatment system according to claim 12, since the oxygen-containing gas is supplied to one or both of the constant temperature chamber and the duct, the oxygen-containing gas is supplied to the constant temperature chamber. Easy to do.
In the polychlorinated biphenyl contaminant treatment system according to claim 13, since the oxygen-containing gas is further supplied into the plasma decomposition furnace, the polychlorinated biphenyl and its decomposition products can be oxidized even in the plasma decomposition furnace. Can treat polychlorinated biphenyl contaminants more efficiently.

Next, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention.
Here, FIG. 1 is an explanatory view of a polychlorinated biphenyl contaminant treatment system according to the first embodiment of the present invention, FIG. 2 is an explanatory view of a plasma decomposition apparatus of the treatment system, and FIG. FIG. 4 is an explanatory diagram of a polychlorinated biphenyl contaminant treatment system according to a third embodiment of the present invention, and FIG. 4 is an explanatory diagram of a polychlorinated biphenyl contaminant treatment system according to a third embodiment of the present invention.

As shown in FIGS. 1 and 2, the polychlorinated biphenyl contaminant treatment system (hereinafter also referred to as “PCB treatment system”) 10 according to the first embodiment of the present invention is a polychlorinated biphenyl contaminant (PCB). This is an apparatus for detoxifying the pollutants 11 by plasma processing in the plasma decomposition furnace 12. The PCB processing system 10 includes a plasma decomposition furnace 12 that contains PCB contaminants 11 and a plasma torch 13 that generates a plasma arc in a high temperature state and is provided in the plasma decomposition furnace 12, and decomposes the PCB with the plasma arc. A decomposing apparatus 14, an oxygen supply means 15 for directly supplying air, which is an example of an oxygen-containing gas, into the plasma decomposing furnace 12, a cooler 16 for cooling the exhaust discharged from the plasma decomposing furnace 12, and a cooler 16. It has the boiler 17 which heat-exchanges the heat | fever of the cooled exhaust_gas | exhaustion, and the electric dust collector 18 which collects solid components, such as soot, contained in exhaust_gas | exhaustion. Hereinafter, each device will be described in detail.

PCB contaminants 11 are, for example, sludge, waste, ballast, pressure-sensitive copying paper, rough dismantled products of PCB-containing electrical equipment such as transformer cores and capacitor elements, and waste activated carbon used for local exhaust purification. Any one or two or more are usually sealed in a drum 20 which is a metal container (see FIG. 2).

Adjacent to the plasma decomposition furnace 12, the plasma decomposition apparatus 14 is provided with a charging chamber 21 into which a drum can 20 in which PCB contaminants 11 are enclosed in the plasma decomposition furnace 12. The charging chamber 21 is provided with a partition plate 22 having a heat resistance function for sequentially feeding the drum cans 20 into the plasma decomposition furnace 12 one by one, for example, one by one.

The plasma decomposition furnace 12 is provided with an input port 23 that communicates with the input chamber 21 and carries the drum can 20 sent from the input chamber 21 into the plasma decomposition furnace 12. The plasma decomposition furnace 12 is provided with one or a plurality of, for example, two plasma torches 13 for generating a plasma arc in the plasma decomposition furnace 12.

The plasma torch 13 is a non-transition type having anode and cathode electrodes (not shown). The plasma torch 13 is energized while continuously supplying gas (for example, air) between the anode and the cathode, and is heated to a high temperature, for example, about 15000 ° C. A plasma arc (air plasma) is generated, and plasma decomposition of the PCB is performed by this plasma arc. Note that the plasma torch may be a transition type in which an anode is provided in the plasma torch and an object to be melted is a cathode. The temperature in the plasma decomposition furnace 12 is 1100 to 1400 ° C., and the metal drum 20 can be melted. The plasma torch 13 is movable, and the inside of the plasma decomposition furnace 12 is observed with a camera (not shown), and the plasma torch 13 can be moved so as to irradiate a plasma arc toward an untreated drum can. .

Further, exhaust (including, for example, carbon dioxide, water (water vapor), hydrogen chloride, etc.) generated when PCB is decomposed in the plasma decomposition furnace 12 is passed through the ceiling of the plasma decomposition furnace 12. An exhaust port 24 for discharging to the outside is provided in a continuous manner.
Further, the plasma decomposition furnace 12 discharges the slag 25 generated from the drum 20 generated in the plasma decomposition furnace 12 and the molten components of the PCB contaminant 11 such as earth, sand, metal, and concrete to the outside of the plasma decomposition furnace 12. A slag discharge port 26 is provided.

The plasma decomposition apparatus 14 is provided with slag unloading means 27 for unloading the slag 25 discharged from the slag discharge port 26 from the plasma decomposition furnace 12. The slag unloading means 27 is disposed below the slag discharge port 26 provided in the lower part of the plasma decomposition furnace 12, and includes one or a plurality of slag unloading containers 28 capable of storing a predetermined amount of slag 25, and the slag unloading container 28. It includes moving means (for example, a conveyor or the like) (not shown) that sequentially feeds.

The oxygen supply means 15 includes a pump 29 that sends air directly into the plasma decomposition furnace 12 from a gas supply port (not shown) provided in the plasma decomposition furnace 12, and a gas supply pipe 30 that is connected from the pump 29 to the gas supply port. I have. Oxygen in the air supplied into the plasma decomposition furnace 12 completely stabilizes the PCB decomposition products (dioxin precursors, benzene, chlorides, etc.) decomposed by the plasma arc and undecomposed PCB. The detoxified material, such as carbon dioxide, water, and hydrogen chloride, is rendered harmless. Therefore, resynthesis of PCB and synthesis (generation) of dioxins having higher toxicity than PCB can be suppressed. Further, carbon monoxide or carbon generated by plasma decomposition can be oxidized to carbon dioxide. Furthermore, resynthesis of by-products (dioxins) contained in the PCB can also be suppressed.

Thus, when supplying an oxygen-containing gas into the plasma decomposition furnace 12, the PCB exhaust decomposed by the plasma decomposition apparatus is maintained at 1100 to 1400 ° C. for 5 seconds as in the conventional case, and the PCB is completely removed. There is no need for a constant temperature chamber that decomposes or a temperature-decreasing tower that cools rapidly so as not to re-synthesize PCB or the like from the decomposition product of PCB decomposed in the constant temperature chamber. In addition, oxygen may be supplied into the plasma decomposition furnace 12 instead of air so that the inside of the plasma decomposition furnace 12 is substantially in an oxygen atmosphere so that nitrogen oxides are not generated.

In the cooler 16, the high-temperature exhaust of 1100 to 1400 ° C. discharged from the exhaust port 24 of the plasma decomposition furnace 12 is cooled to a temperature not higher than the heat resistance temperature of the boiler 17 disposed on the downstream side, for example, 1100 ° C. or lower. Moreover, the boiler 17 can use the existing thing, The exhaust_gas | exhaustion of 1100 degrees C or less is cooled to about 300 degreeC, for example, and the heat | fever of exhaust_gas | exhaustion is collect | recovered. Here, since the PCB or the like is not synthesized from the exhaust gas generated from the plasma decomposition furnace 12, it may be cooled to 800 to 400 ° C., which is a temperature range where the PCB is re-synthesized. Further, the electric dust collector 18 collects solid components contained in the exhaust. A bag filter may be used when the exhaust temperature is about 200 ± 20 ° C. Further, the exhaust gas may be diffused to the atmosphere through a catalytic reaction tower and an activated carbon tank (not shown).

Next, a method for treating the PCB contaminant 11 using the PCB treatment system 10 will be described.
First, a plasma arc of about 15000 ° C. is generated by the plasma torch 13 while driving the pump 29 and supplying air into the plasma decomposition furnace 12.
Next, the drum can 20 enclosing the PCB contaminant 11 is placed in the charging chamber 21 of the plasma decomposition apparatus 14, and the partition plate 22 is operated to supply the drum can 20 in the charging chamber 21 to the plasma decomposition furnace 12.

Due to the generated plasma arc, the inside of the plasma decomposition furnace 12 becomes about 1100 to 1400 ° C., the drum 20 is melted, and the PCB is decomposed to the atomic level. Further, the decomposition product of PCB is oxidized by oxygen in the plasma decomposition furnace 12, and exhaust gas containing, for example, carbon dioxide, water (water vapor), and hydrogen chloride is generated and harmlessly stabilized. In addition, when oxygen plasma is generated by the plasma torch 13, the PCB and its decomposition products are more efficiently oxidized.

Here, the generated exhaust gas is discharged from the exhaust port 24 of the plasma decomposition furnace 12, cooled to 1100 ° C. or less by the cooler 16, recovered by the boiler 17, and then the solid components are removed by the electric dust collector 18. Further, the slag 25 generated in the plasma decomposition furnace 12 is supplied from the slag discharge port 26 of the plasma decomposition furnace 12 to the slag carry-out container 28 and is carried out of the plasma decomposition furnace 12.

A polychlorinated biphenyl contaminant treatment system 40 according to a second embodiment of the present invention will be described with reference to FIG. Note that the same components as those in the PCB processing system 10 are denoted by the same reference numerals, and detailed description thereof is omitted.
The PCB processing system 40 is different from the PCB processing system 10 in that the gas supply pipe 30 is connected from the pump 29 to the plasma torch 13. Thereby, in the plasma decomposition furnace 12, air plasma (especially oxygen plasma) is generated, and after the PCB and its decomposition products are thermally decomposed, they can be quickly oxidized and harmlessly stabilized. When oxygen-containing gas supplied to the plasma torch 13 is oxygen, oxygen plasma can be generated with high efficiency, and oxidation of PCB and its decomposition products can be promoted.

With reference to FIG. 4, a polychlorinated biphenyl contaminant treatment system 50 according to a third embodiment of the present invention will be described. Note that the same components as those of the PCB processing systems 10 and 40 are denoted by the same reference numerals, and detailed description thereof is omitted.
The PCB processing system 50 is connected to the plasma decomposition furnace 12 via a duct 51, and undecomposed polychlorinated biphenyl and polychlorinated biphenyl contained in exhaust gas generated when the polychlorinated biphenyl is thermally decomposed in the plasma decomposition furnace 12. Is maintained at 1100 to 1400 ° C. for 1 to 5 seconds to completely decompose, and the pump 51 is connected to the duct 51 via the gas supply pipe 30. It differs from the PCB processing systems 10 and 40 in that air (oxygen-containing gas) is supplied.

As a result, in the constant temperature chamber 52, undecomposed polychlorinated biphenyl and polychlorinated biphenyl degradation products contained in the exhaust gas generated when the polychlorinated biphenyl is thermally decomposed in the plasma decomposition furnace 12 are completely oxidized. The resynthesis of polychlorinated biphenyl can be suppressed. Therefore, normally, a temperature reducing tower disposed downstream of the constant temperature chamber 52 is not necessary.
In the PCB processing system 50, the gas supply pipe 30 is connected to the duct 51. However, the oxygen-containing gas may be directly supplied into the constant temperature chamber 52 by connecting to the constant temperature chamber 52. Further, an oxygen-containing gas may be supplied to both the duct 51 and the constant temperature chamber 52. Further, an oxygen-containing gas may be supplied into the plasma decomposition furnace 12 to oxidize polychlorinated biphenyl and its decomposition products in the plasma decomposition furnace 12 to treat the polychlorinated biphenyl contaminants more efficiently.

The present invention is not limited to the above-described embodiment, and can be changed without changing the gist of the present invention. For example, some or all of the above-described embodiments and modifications are possible. A combination of the above and the like constitutes the polychlorinated biphenyl contaminant treatment method and treatment system of the present invention are also included in the scope of the present invention.

For example, in the treatment method and treatment system for polychlorinated biphenyl contaminants of the above embodiment, a pump is used to supply the oxygen-containing gas directly to the plasma decomposition furnace, but a plasma decomposition furnace is provided outside the plasma decomposition furnace. An enclosing hermetically sealed container may be arranged, the inside of the hermetically sealed container may be set to a positive pressure, the inside of the plasma decomposition furnace may be set to a negative pressure, and the sealed container may be filled with an oxygen-containing gas. The oxygen supply gas may be supplied into the plasma decomposition furnace by supplying the oxygen-containing gas directly into the plasma decomposition furnace or via a plasma torch. Furthermore, although the exhaust gas produced by decomposing polychlorinated biphenyl was treated with a cooler, a boiler, and an electrostatic precipitator, the exhaust gas may be treated using a conventional apparatus.

It is explanatory drawing of the processing system of the polychlorinated biphenyl contaminant which concerns on the 1st Embodiment of this invention. It is explanatory drawing of the plasma decomposition apparatus of the processing system. It is explanatory drawing of the processing system of the polychlorinated biphenyl contaminant which concerns on the 2nd Embodiment of this invention. It is explanatory drawing of the processing system of the polychlorinated biphenyl contaminant which concerns on the 3rd Embodiment of this invention.

Explanation of symbols

10: Polychlorinated biphenyl contaminant treatment system, 11: Polychlorinated biphenyl contaminant, 12: Plasma decomposition furnace, 13: Plasma torch, 14: Plasma decomposition apparatus, 15: Oxygen supply means, 16: Cooler, 17: Boiler , 18: electrostatic precipitator, 20: drum can, 21: input chamber, 22: partition plate, 23: input port, 24: exhaust port, 25: slag, 26: slag discharge port, 27: slag discharge means, 28: slag transfer Container: 29: pump, 30: gas supply pipe, 40: polychlorinated biphenyl contaminant treatment system, 50: polychlorinated biphenyl contaminant treatment system, 51: duct, 52: constant temperature chamber

Claims (13)

In the method for treating polychlorinated biphenyl contaminants, in which polychlorinated biphenyl contaminants are placed in a plasma decomposition furnace, and the polychlorinated biphenyls are thermally decomposed by a high-temperature plasma arc generated from a plasma torch provided in the plasma decomposition furnace.
A method for treating polychlorinated biphenyl contaminants, wherein an oxygen-containing gas is supplied into the plasma decomposition furnace to stabilize the polychlorinated biphenyl contaminants harmlessly. 2. The method for treating polychlorinated biphenyl contaminants according to claim 1, wherein an oxygen-containing gas is used as the plasma arc gas. 3. The method for treating a polychlorinated biphenyl contaminant according to claim 1, wherein the oxygen-containing gas is an oxygen gas, and the plasma decomposition furnace is substantially in an oxygen atmosphere. A method for treating polychlorinated biphenyl contaminants. Polychlorinated biphenyl contaminants are placed in the plasma decomposition furnace, and the polychlorinated biphenyl is pyrolyzed by a high-temperature plasma arc generated from the plasma torch provided in the plasma decomposition furnace, and is contained in the exhaust generated at that time Undecomposed polychlorinated biphenyl and polychlorinated biphenyl degradation products are maintained at 1100 to 1400 ° C. for 1 to 5 seconds in a constant temperature chamber connected to the plasma decomposition furnace via a duct for complete decomposition. In the method of treating biphenyl contaminants,
A method for treating polychlorinated biphenyl contaminants, wherein an oxygen-containing gas is supplied to one or both of the thermostatic chamber and the duct to stabilize the polychlorinated biphenyl contaminants harmlessly. 5. The method for treating polychlorinated biphenyl contaminants according to claim 4, further comprising supplying an oxygen-containing gas into the plasma decomposition furnace. The method for treating polychlorinated biphenyl contaminants according to any one of claims 4 and 5, wherein the oxygen-containing gas is oxygen gas. A plasma decomposition furnace for containing polychlorinated biphenyl contaminants, and a plasma torch that is provided in the plasma decomposition furnace and generates a high-temperature plasma arc, supplying an oxygen-containing gas into the plasma decomposition furnace And polychlorinated biphenyl contaminant treatment system. 8. The polychlorinated biphenyl contaminant treatment system according to claim 7, wherein the oxygen-containing gas is directly supplied into the plasma decomposition furnace. 9. The system for treating a polychlorinated biphenyl contaminant according to claim 8, wherein a sealed container surrounding the plasma decomposition furnace is disposed outside the plasma decomposition furnace, and the inside of the closed container is at a positive pressure. The system for treating polychlorinated biphenyl contaminants, wherein the negative pressure is applied and the sealed container is filled with the oxygen-containing gas. The polychlorinated biphenyl contaminant treatment system according to any one of claims 7 to 9, wherein the oxygen-containing gas is supplied into the plasma decomposition furnace through the plasma torch. Biphenyl chloride contaminant treatment system. A plasma decomposition furnace containing polychlorinated biphenyl contaminants, a plasma torch which is provided in the plasma decomposition furnace and generates a high-temperature plasma arc, and is connected to the plasma decomposition furnace via a duct; A polychlorinated biphenyl contaminant treatment system comprising: a constant temperature chamber that holds exhaust at 1100 to 1400 ° C. for 1 to 5 seconds, and supplying an oxygen-containing gas into the constant temperature chamber. 12. The polychlorinated biphenyl contaminant treatment system according to claim 11, wherein the oxygen-containing gas is supplied to one or both of the constant temperature chamber and the duct. Processing system. 13. The polychlorinated biphenyl contaminant treatment system according to claim 12, wherein the oxygen-containing gas is further supplied into the plasma decomposition furnace.

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