JP2000325735A - Adsorption body for plasma treatment and apparatus and method for decomposition of hazardous substance using the adsorption body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently treat hazardous substance by plasma by a method wherein for an adsorbent which adsorbs the hazardous substance, and decomposes the adsorbed substance by plasma treatment, an intensive dielectric is arranged inside the adsorbent. SOLUTION: A plasma treating adsorption body 100 is an adsorbent which adsorbs hazardous substance, and decomposes the adsorbed substance by plasma treatment, and formed by arranging a ferroelectric body 102 inside the porous adsorbent 101. In this case a dielectric constant of the ferroelectric body 102 is 1-20. When plasma treatment of the hazardous substance is carried out, the adsorbent 100 is filled in a plasma treating container, and the hazardous substance is adsorbed in a pore of the adsorbent 101 part. Thereafter, plasma treatment is carried out in a state wherein the hazardous substance is adsorbed inside the adsorbent 101 as it is. Then, an electric field can be applied selectively to a surface of the absorbent 101 and in its inner macro pore by optimizing an electrostatic capacity of a void generated in the adsorbent 100.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to various incinerators such as municipal waste incinerators, industrial waste incinerators, sludge incinerators, etc.
It relates to technology for purifying harmful substances such as exhaust gas emitted from pyrolysis furnaces, melting furnaces, and various industries such as food manufacturing and chemical manufacturing industries, and exhaust gas generated from vehicles, etc., particularly contained in exhaust gas. Halogenated aromatic compounds such as dioxins, highly condensed aromatic hydrocarbons, environmental hormones, nitrogen oxides, sulfur oxides, volatile organic compounds, etc.
Also, the present invention relates to an adsorbent for plasma treatment for detoxification at the same time, and an apparatus and method for decomposing harmful substances using the adsorbent.

[0002]

BACKGROUND ART For example NO _X, VOC (volatile organic compounds, Volatile Organic Compound), harmful substances such as ethylene, a method in particular for decomposing toxic gas or the like, a method of performing plasma processing is known. Hereinafter, a conventional gas plasma processing method will be described.

FIG. 10 is a configuration diagram of a conventional gas decomposition apparatus. As shown in FIG. 10, in the conventional gas decomposition apparatus, a linear electrode 02 is provided at the center of a cylindrical container 01, and the container 01 is grounded and used as a negative electrode. The linear electrode 02 is a positive electrode and is connected to a high-voltage pulse power supply 03.

In the case of decomposing harmful substances in a gas by the gas decomposer, for example, an exhaust gas 06 discharged from an engine 04 flows into a vessel 01 through a pipe 05 (arrow D), and a voltage is applied to the linear electrode 02. To the container 0
By giving a potential difference between 1 and the linear electrode 02,
The harmful substances are decomposed by plasma treatment of the exhaust gas 06 by plasma discharge.

[0005] This plasma treatment decomposition proceeds by the following reaction. That is, the moisture (H
₂ O), nitrogen (N ₂ ), and oxygen (O ₂ ) are ionized and radicalized (activated) by the following chemical reaction formulas (1) to (3) by plasma treatment. Here, in the following, the symbol * indicates a radicalized product.

H ₂ O + e → H * + OH * + e (1) N ₂ + e → 2N * + e (2) O ₂ + e → 2O * + e (3) Here, the above reaction formulas (1) to (3) H generated in
*, 2N *, and O * are a hydrogen radical, a nitrogen radical, and an oxygen radical, respectively, and are chemically unstable because they are radicalized (activated). Therefore, the oxygen radical (O *) reacts with NO, which is a harmful substance in the exhaust gas, as shown in the following reaction formula (4), and chemically stable NO ₂
Generate NO + O * → NO ₂ (4) Next, NO ₂ reacts with OH * as shown in the following chemical reaction formula (5). NO ₂ + OH * → HNO ₃ (5)

As described above, in the conventional plasma processing,
As shown in the reaction formula (5), nitric acid (HNO ₃ ) is produced as a by-product. Therefore, this nitric acid is then neutralized by adding NH ₃ (ammonia) to make it into powdery nitrate,
Had been disposed of.

[0008]

The above conventional plasma processing method has the following problems. The first problem is that since the exhaust gas to be treated is subjected to plasma processing while flowing in the container 01, the concentration does not increase when the exhaust gas concentration in the container 1 is low. Therefore, since the exhaust gas having a low concentration of harmful substances is subjected to the plasma treatment, the reactions of the reaction formulas (4) and (5) are difficult to proceed sufficiently, and the amount of decomposition of the exhaust gas is small accordingly. The first problem is a problem that occurs when the exhaust gas is processed while continuously flowing in the container 01.

Second, nitric acid (HNO ₃ ) is generated as a by-product when NOx is decomposed, and a neutralizing agent (NH ₃ ) is added to the nitric acid to produce nitric acid. Since the processing has to be performed, the number of processing steps is large and time-consuming, and the processing cost is increased. The second problem is a problem caused by performing the plasma processing in the air, that is, in the oxygen atmosphere.

Accordingly, an object of the present invention is to provide an adsorbent for plasma treatment capable of efficiently performing plasma treatment of harmful substances, an apparatus and a method for decomposing harmful substances using the adsorbent.

[0011]

Means for Solving the Problems The invention of claim 1 which solves the above-mentioned problem is an adsorbent which adsorbs harmful substances and decomposes the adsorbed substances by plasma treatment. It is characterized in that a dielectric is provided.

According to a second aspect of the present invention, in the first aspect, the ferroelectric has a relative dielectric constant of 1000 or more, and the adsorbent has a relative dielectric constant of 1 to 20.

According to a third aspect of the present invention, in the first aspect, the adsorbent has a macropore of 4 to 100 μm.

According to a fourth aspect of the present invention, there is provided a first electrode, a second electrode, a potential difference applying means for applying a potential difference between the first electrode and the second electrode, and the first electrode The harmful substance is adsorbed by being disposed between the first electrode and the second electrode.
And a plasma processing container containing the adsorbent according to any one of the above, and by applying a potential difference between the first electrode and the second electrode, the harmful substance adsorbed by the adsorbent is adsorbed. It is characterized in that it decomposes inside, on the surface and near the material.

According to a fifth aspect of the present invention, there is provided a first electrode, a second electrode, a commercial frequency high voltage power supply for applying a high voltage between the first electrode and the second electrode, 4. A suction device according to claim 1, wherein a high-voltage pulse power supply for superposing a high-voltage pulse on a high-frequency voltage and a harmful substance are disposed between the first electrode and the second electrode. A plasma processing container for accommodating a body, and applying a potential difference between the first electrode and the second electrode so that the harmful substances adsorbed by the adsorbent can be removed from the interior, surface and the adsorbent thereof. It is characterized in that it is decomposed in the vicinity.

According to a sixth aspect of the present invention, in the fourth or fifth aspect, the adsorbent accommodated in the plasma processing apparatus satisfies the following formulas (1) and (2), and the vicinity of the adsorbent surface and the inside of the adsorbent are included. And selectively applying an electric field to the macropores. 0 ≦ k1 ≦ 1 (1) 0.5 ≦ k2 ≦ 0.9 (2) where k1 = gap distance (dg) between adsorbents /
Adsorbent thickness (da) k2 = ferroelectric diameter (φs) / adsorbent diameter (φa).

According to a seventh aspect of the present invention, in the sixth aspect, the spacer is accommodated together with the adsorbent accommodated in the plasma processing apparatus, and the expressions (1) and (2) are satisfied.

The invention according to claim 8 is characterized in that, in claim 7, the spacer carries a photocatalyst.

According to a ninth aspect of the present invention, there is provided the decomposition apparatus according to the fourth or fifth aspect, wherein the gas supply means for supplying exhaust gas to the adsorbent of each decomposition apparatus and the decomposed gas from the adsorbent are provided. A gas discharging means for discharging gas is provided.

The invention of claim 10 is the invention of claim 4 or 5
Or 9 is characterized in that a reducing gas supply means for supplying a reducing gas into the plasma processing vessel is provided.

[0021] The invention of claim 11 is the invention of claims 4 to 1
0, wherein the harmful substance is exhaust gas discharged from an incinerator, a pyrolysis furnace, a melting furnace, or the like.

According to the invention of claim 12, in claim 12, the harmful substance in the exhaust gas is selected from dioxins, polyhalogenated biphenyls, halogenated benzenes, halogenated phenols and halogenated toluenes. It is characterized in that it is at least one halogenated aromatic compound, a highly condensed aromatic hydrocarbon, and an environmental hormone.

[13] The invention of claim 13 is an exhaust gas treatment apparatus for purifying exhaust gas discharged from an incinerator, a pyrolysis furnace, a melting furnace, etc., and a dust removal apparatus for removing dust in the exhaust gas, and the dust removal apparatus. A harmful substance decomposing apparatus according to any one of claims 4 to 13 provided on the downstream side of the apparatus.

According to a fourteenth aspect of the present invention, a harmful substance is supplied to the adsorbent according to any one of the first to third aspects disposed between the first electrode and the second electrode. A harmful substance is adsorbed on the material, and a potential difference is applied between the first electrode and the second electrode by a potential difference applying means in that state, so that the harmful substance adsorbed on the adsorbent is removed from the inside, surface, and It is characterized in that it is decomposed in the vicinity.

According to a fifteenth aspect of the present invention, there is provided a first electrode, a second electrode, a potential difference applying means for applying a potential difference between the first electrode and the second electrode, and the first electrode And the second
4. A plurality of plasma processing vessels comprising the adsorbent according to any one of claims 1 to 3 disposed between the electrodes and adsorbing harmful substances, and each of the plasma processing vessels is provided with a plurality of plasma processing vessels. 3. A method for decomposing harmful substances by a harmful substance decomposition apparatus provided with a harmful substance supply means for supplying harmful substances to the adsorbent and a harmful substance discharge means for discharging harmful substances from the adsorbent. A harmful substance is supplied to the adsorbent in the plasma processing vessel, and the harmful substance adsorbed by each adsorbent is decomposed.

The invention of claim 16 is characterized in that, in claim 14 or 15, plasma decomposition is performed in a reducing gas atmosphere.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described, but the present invention is not limited thereto.

[First Embodiment] FIG. 1 is a schematic diagram of a plasma processing adsorbent according to a first embodiment of the present invention.
As shown in FIG. 1, the adsorbent 100 for plasma treatment of the present embodiment is an adsorbent that adsorbs harmful substances and decomposes the adsorbed substances by plasma treatment.
The ferroelectric material 102 is provided inside the device 01.
Here, the relative permittivity of the ferroelectric 102 is 1000 or more, and the relative permittivity of the adsorbent 101 is 1 to 20.

When the harmful substance plasma treatment is performed using the adsorbent 100 including the adsorbent 101 on which the ferroelectric substance having the specific dielectric constant is disposed, the adsorbent 1 is used.
After the harmful substance is adsorbed in the pores of the adsorbent 101 portion, the plasma treatment is performed while the harmful substance remains adsorbed inside the adsorbent 101.

FIG. 2 shows an example of an outline of an apparatus for decomposing harmful substances provided with this plasma processing container. As shown in FIG. 2, the harmful substance decomposition apparatus 100 according to the present embodiment
Are a first electrode 111 and a second electrode 112, a potential difference providing means 113 for providing a potential difference between the first electrode 111 and the second electrode 112, and a first electrode 111 and a second electrode 112. A plasma processing vessel 114 for accommodating the adsorbent 100 that is disposed between the electrodes 112 and adsorbs the harmful substance, wherein the first electrode 111 and the second electrode 11
By applying a potential difference between the two adsorbents 100
The harmful substance adsorbed by the adsorbent 101 is decomposed inside, on the surface of the adsorbent 100 and in the vicinity thereof.

Although the electrodes 111 and 112 are plate-shaped electrodes, they may be line-to-plate or line-to-cylinder. The container 114 is made of an insulating material such as glass. One side of the container 114 is connected to gas introducing means 117 having an openable / closable valve 116 for introducing exhaust gas 115 containing harmful substances, and the other side is provided with an openable / closable valve 118. Connected gas discharging means 119 is connected. As the potential difference applying means 113, a power supply such as a high-voltage AC power supply or a pulsed power supply is connected to the first electrode 111 (positive side electrode). The second electrode 112 (negative electrode) is ground 1
20. The valves 116, 11
7 and the like are automatically controlled by control means (not shown) such as a CPU.

In the above decomposition apparatus, the adsorbent 100
Is filled in the plasma processing vessel 114, a gap d is generated between the adsorbents 100, 100 due to the packing density,
By optimizing the capacitance ratio of the gap d, an electric field can be selectively applied to the surface of the adsorbent 101 and the macropores in the adsorbent 101.

The adsorbent 101 is not particularly limited as long as it has a property capable of adsorbing and holding harmful substances. For example, when adsorbing ethylene gas (food storage), Na-X is used. When adsorbing MEK (methyl ethyl ketone), high silica zeolite, USY,
With ZSM-5, pentasil-type zeolite in the case of adsorbing NOx, using a Cu-ZSM ₅ or the like, using a mesoporous silicate when adsorbing dioxins, when the adsorption of VOC (volatile organic compounds) Uses high silica zeolite, USY, ZSM-5, and when adsorbing dichloroethylene, Na-Y or the like can be used.

Although the material of the ferroelectric is not particularly limited, for example, barium titanate can be exemplified.

In order to selectively apply electrolysis in the adsorbent 100, as shown in FIG. 3, it is necessary to design the shape and arrangement of the adsorbent satisfying the following parameters (1) and (2). There is. 0 ≦ k1 ≦ 1 (1) 0.5 ≦ k2 ≦ 0.9 (2) where k1 = gap distance (dg) between adsorbents /
Adsorbent thickness (da) k2 = ferroelectric diameter (φs) / adsorbent diameter (φa). In equation (1), when the constant k1 is 0, the adsorbents 100, 100 are close to each other. When the constant k1 is 1, the adsorbents 100, 100 are equal in thickness to the adsorbent 101. Are far away. On the other hand, when the constant k2 exceeds 0.9, the adsorption performance is remarkably reduced, which is not preferable. The above-mentioned predetermined arrangement may be achieved by providing a concavo-convex surface to the shape of the adsorbent 101 or by using a spacer 104 having a predetermined shape such as a sphere.
When filling the inside with the adsorbent 100, it may be filled together. The size of the spacer 104 may be designed so as to satisfy the parameters (1) and (2).
The material is not particularly limited.

In particular, the material of the spacer 104 is TiO.
By using a photocatalyst such as _{2, the} synergistic effect of not only decomposing the harmful substance by the plasma treatment but also decomposing the harmful substance by the oxidative decomposition of the photocatalyst using the ultraviolet light emitted by the plasma processing is exhibited. Is done. In FIG. 3A, reference numeral 105 denotes a plasma portion.

That is, in the present invention, harmful substances (eg, NO
_X ) indicates that the following chemical reactions (6) and (7) are decomposed by the above-described plasma decomposition, and when the photocatalyst is supported on the spacer 104 as described above, the following chemical reaction (6) and (7) is performed by the photocatalytic decomposition. Decomposition of 8) and (9) proceeds. Further, the generated reaction product such as nitric acid is excited and desorbed by the collision of plasma, and can be rendered harmless by adding NH ₃ on the downstream side to form ammonium nitrate. Note that although nitrogen oxides (NO _X) and as an example to explain the mechanism of degradation as hazardous substances, as described below, decomposition targets of the present invention is not limited any way.

<Decomposition by Plasma> NO + O → NO ₂ (6) NO ₂ + OH → HNO ₃ (7) <Decomposition by Photocatalyst> NO + O → NO ₂ (8) NO ₂ + OH → HNO ₃ (9)

The photocatalyst is not particularly limited as long as it is a commonly used photocatalyst. For example, titanium oxide (TiO ₂ ), zinc oxide (ZnO), iron oxide (F
e ₂ O ₃ ), tin oxide (SnO ₂ ), tungsten oxide (WO), and bismuth oxide (BiO ₃ ), but the present invention is not limited thereto. Any photocatalyst may be used as long as it causes decomposition. Of the above photocatalysts, titanium oxide is particularly preferable, and anatase type TiO ₂ and rutile type Ti
Any of O ₂ may be used.

Here, the harmful substances in the exhaust gas to be decomposed in the present invention include nitrogen oxides, dioxins and PCs.
Hazardous substances such as harmful aromatic compounds represented by Class B, harmful substances such as aromatic hydrocarbons with a high degree of condensation, and gaseous organic compounds, are harmful in exhaust gas that can be decomposed by the plasma decomposition and photocatalytic decomposition of the present invention. Substance (or environmental hormone)
However, it is not limited to these.

Here, the above dioxins are a general term for polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs).
It is said to be generated in trace amounts during the combustion of chlorine compounds and certain organic chlorine compounds, and is a chemically colorless crystal. There are 75 types of PCDDs and 135 types of PCDFs depending on the number of chlorines, from dichloride to octachloride. Of these, dibenzo-p-dioxin tetrachloride (T ₄ CDD) is the most common. It is known to be highly toxic. In addition, as harmful chlorinated aromatic compounds, in addition to dioxins, various organic chlorine compounds (for example, aromatic compounds such as phenol and benzene (for example, chlorobenzenes, chlorophenol and chlorotoluene) ), Chlorinated alkyl compounds, etc.) and must be removed from the exhaust gas. The dioxins include not only chlorinated aromatic compounds but also halogenated dioxins such as Br-dioxins.

PCBs (polychlorinated biphenyls)
Is a generic term for compounds in which several chlorine atoms are added to biphenyl, and there are isomers depending on the number of chlorine substitutions and substitution positions.
Typical are 2,6-dichlorobiphenyl, 2,2'-dichlorobiphenyl, 2,3,5-trichlorobiphenyl, etc., which are highly toxic and may generate dioxins when incinerated. Known as
It must be removed from the exhaust gas. In addition, coplanar P
CB is also included.

The aromatic hydrocarbon having a high degree of condensation is a general term for polynuclear aromatic compounds, which may contain one or more OH groups, is recognized as a carcinogen, and needs to be removed from exhaust gas. .

In many cases, exhaust gas containing gaseous organic compounds such as formaldehyde, benzene or phenol in addition to dust may be generated. These organic compounds are also environmental pollutants and significantly impair human health and need to be removed from the exhaust gas.

The nitrogen oxides to be treated in the present invention usually mean NO and NO ₂ , and also a mixture thereof.
It is also called NOx. However, the NOx often contains nitrogen oxides having various oxidation numbers and being unstable in addition to the above. Accordingly, x is not particularly limited, but is usually a value of 1 to 2. It becomes nitric acid, nitrous acid, etc. in rainwater or NO, or NO is said to be one of the main causes of photochemical smog, and is a harmful compound to the human body.

VOC (volatile organic compound)
It is particularly generated in chemical factories, printing factories, coating factories, etc., and includes, for example, hydrocarbons such as benzene, toluene, xylene, methane, butane, hexane, and cyclohexane, lower alcohols such as methanol and isopropanol, acetone, methyl ethyl ketone ( Examples include ketones such as MEK), organic acids such as formic acid and acetic acid, aldehydes such as formaldehyde and acetaldehyde, chlorofluoromethane, halocarbons such as chloromethane, dichloromethane, trichloroethane and trichloroethylene, ethyl acetate, butyl acetate, and ammonia. However, the present invention is not limited to this.

That is, the above-mentioned harmful substances such as nitrogen oxides, dioxins, and highly condensed aromatic carbon are obtained by performing a plasma treatment using an adsorbent comprising an adsorbent having a ferroelectric substance disposed therein according to the present invention. Harmful substances such as hydrogen and gaseous organic compounds can be detoxified by plasma decomposition and oxidative decomposition.

Here, the principle of plasma decomposition of dioxins is not clear at present, but an example of the decomposition mechanism will be described with reference to the following "Chemical Formula 1". Physical collisions of high-energy electrons in the plasma dissociate the tail bonds of dioxins or break the benzene ring. Also, high-energy electrons collide with dioxins, and the impact decomposes ether bonds and benzene rings. Further, it is presumed that water and N ₂ in the exhaust gas are decomposed by plasma discharge to generate N *, O *, and OH *, which are decomposed by these radicals.

[0049]

Embedded image

[Second Embodiment] FIG. 4 is a schematic diagram of a plasma processing adsorbent according to a second embodiment of the present invention.
A case in which plasma is ideally formed inside and near the surface of the adsorbent will be described. Here, FIG. 4A is a state diagram in which plasma is generated in the left-right direction of the adsorbent due to resonance vibration of the pulse discharge of the adsorbent, and FIG. 4B is a schematic internal view of a macropore of the adsorbent. It is. As shown in FIG. 4A, the adsorbent 101 constituting the adsorbent 100 includes a micropore (up to several tens of degrees) 101a and a macropore 101b.
In order to generate plasma in the macropore 101b, the diameter of the macropore is set to 4 to
It is preferably 100 μm. This is because if it is less than 4 μm, the mean free path of electrons is 4 μm (atmospheric pressure, normal temperature), and the electrons cannot be accelerated.
This is because if it is not less than 00 μm, the ability to adsorb harmful substances is reduced. Preferably, the thickness is 4 to 10 μm. In FIG. 4 (B), plasma is generated, and the avalanche progresses due to streamer discharge.
The harmful substances that occur to the inside and are adsorbed in the adsorbent can be plasma-decomposed. The adjustment of the diameter of the macropore is not particularly limited as long as it is a known method. For example, a binder and a pore material (Avicel) may be used during zeolite granulation.
Can be adjusted by inserting. The proportion of the pores may be adjusted by the proportion of the pore material.

[Third Embodiment] FIG. 5 is a schematic diagram of a plasma processing / decomposing apparatus according to a third embodiment.
It is obtained by superimposing a high voltage pulse on a commercial frequency high voltage. As shown in the circuit configuration diagram of FIG. 5A, the first electrode 121 and the second electrode 122 and a commercial frequency high voltage for applying a high voltage between the first electrode 121 and the second electrode 122 are used. A voltage power supply 123, a high voltage pulse power supply 124 for superimposing a high voltage pulse on the commercial frequency high voltage, and an adsorbent disposed between the first electrode 121 and the second electrode 122 for adsorbing harmful substances Plasma processing container 11 accommodating 100
By applying a potential difference between the first electrode 121 and the second electrode 122, the harmful substance adsorbed by the adsorbent is decomposed inside, on the surface of the adsorbent, and in the vicinity thereof. Things.

The reason why the commercial frequency high voltage power supply 123 (50 or 60 Hz sine wave, 50 kV or less) is applied by the commercial frequency high voltage power supply 123 is to generate abundant initial electrons on the surface of the adsorbent 101 in advance. The superimposition of the high-voltage pulse by the high-voltage pulse power supply 124 is performed by accelerating the electrons generated by the application of the commercial frequency high-voltage power supply 123 by the higher-voltage pulse and physically accelerating the electrons in the surface direction of the adsorbent 101. This is to make them collide.
The high voltage pulse has a pulse width of 10 μsec or less and a voltage of 50 KV or less. As shown in the schematic diagram of the voltage application waveform in FIG. 5B, by applying a pulse from a high-voltage pulse power supply having the same polarity as the commercial frequency, electrons are accelerated from the left and right directions of the adsorbent, and as a result, The radical generation efficiency of the entire surface of the substrate 101 is dramatically improved, and power consumption can be reduced. Since electrons are generated in the macropores 101b in the adsorbent 101 in advance, the electrons are similarly accelerated and the decomposition efficiency is improved.

[Fourth Embodiment] Next, the case where the decomposition apparatus of the present invention is applied to the treatment of exhaust gas from an incinerator will be described.

FIG. 6 shows a schematic example of an exhaust gas purifying apparatus using the above harmful component decomposition apparatus, but the apparatus of the present invention is not limited to this.

As shown in FIG. 6, an exhaust gas treatment apparatus according to the present embodiment comprises a cooling device 52 provided on the downstream side of various incinerators 51 for incinerating various kinds of refuse such as municipal waste, industrial waste and sludge. And a bag filter 53 provided downstream of the cooling device 52 for collecting dust, and a decomposition device 110 as shown in FIG. 2 or FIG. 5 for treating exhaust gas after the collection of dust. is there. As a result, the high-temperature exhaust gas from the incinerator is cooled and then dust-removed, and thereafter, the harmful substances in the exhaust gas are decomposed in the decomposer 110, and the exhaust gas obtained by decomposing and removing the harmful substances is discharged from the chimney 55 to the outside. I try to discharge. As a result, harmful substances such as dioxins and nitrogen oxides in the exhaust gas are decomposed, and the purified exhaust gas can be discharged from the chimney.

[Fifth Embodiment] Next, a description will be given of a case where plasma treatment of exhaust gas from a vehicle is performed in a reducing atmosphere.

FIG. 7 is a block diagram of a gas decomposition apparatus according to the fifth embodiment. In FIG. 7, reference numeral 10 denotes a gas decomposition unit, and a container 13 is disposed between a first electrode 11 and a second electrode 12 in a plate shape. The container 13 is made of an insulating material such as glass, and contains an adsorbent 14 therein. The adsorbent 14 is large adsorption capacity of the NO _X contained the like in the exhaust gas of a gasoline engine. At this time, the shape of the electrode is not limited to the plate shape, but may of course include a wire-to-flat plate, a wire-to-cylinder, and the like. The adsorbent 14 may be a porous material. Further, the adsorbent 101 having the ferroelectric substance 102 therein as described above.
(See FIG. 1).

The first electrode 11 is a plasma electrode,
A power supply 15 such as a high-voltage AC power supply or a pulse power supply is connected as a potential difference applying means. The second electrode 12 is a negative electrode and is connected to the ground 16.
When an AC power supply is used as the power supply 15, the adsorbent 14 particularly has a ferroelectric substance. A first pipe 21 is connected to one surface of the container 13, and a second pipe 22 is connected to the other surface. The first pipe 21 has a first valve 2 as an opening / closing means for opening and closing the first pipe 21.
3 is provided, and the second pipe 22 is provided with a second valve 24 as opening and closing means for opening and closing the second pipe 22. The first pipe 21 and the first valve 23 are the container 1
3 constitutes a gas supply means for supplying gas to the adsorbent 14 in the second pipe 3 and the second pipe 22 and the second valve 24.
Are gas discharging means for discharging gas from the adsorbent 14 in the container 13.

A third pipe 25 is connected to the container 13. The third pipe 25 is provided with a third valve 26 as opening and closing means for opening and closing the third pipe 25. The third pipe 25 is connected to a reducing gas supply means 27 such as a nitrogen gas cylinder, and supplies a reducing gas such as nitrogen gas into the container 13 through the third pipe 25. It is not always necessary to provide such reducing gas supply means 27. The valves 23, 24, 26 and the like are automatically controlled by control means (not shown) such as a CPU.

This gas decomposing apparatus has the above-described configuration, and its operation will be described below. With the first valve 23 opened, exhaust gas containing NO is supplied from the gasoline engine (not shown) into the container 13 through the first pipe 21 (arrow A), and NO is adsorbed by the adsorbent 14. .
At this time, the second valve 24 of the second pipe 22 is closed.

When NO has been sufficiently adsorbed by the adsorbent 14, the first valve 23 is preferably closed to prevent the exhaust gas from being supplied from the first pipe 21 so that the inside of the container 13 is substantially sealed. Then, a voltage is applied to the first electrode 11. Here, since the container 13 is hermetically closed and external air hardly enters from the surface of the adsorbent 14 to the inside, the container 13 is almost in a reducing atmosphere from the surface to the inside of the adsorbent 14. This is because the adsorbent surface also selectively adsorbs gas. In this case, desirably, the third valve 26 is opened and the reducing gas supply means 27 is opened.
By supplying a reducing gas such as nitrogen gas into the container 13 from (arrow C), the inside of the container 13 can be further made into a reducing gas atmosphere.

When a voltage is applied to the first electrode 11, a high potential difference is generated between the first electrode 11 and the second electrode 12, and the following reaction formulas (10) and (11)
The radical reaction shown in (1) occurs. 2NO + 2N * → 2N ₂ + 2O (10) 2O → O ₂ (11) That is, as shown in the above reaction formula (10), NO in the exhaust gas becomes nitrogen gas N ₂ in a reducing atmosphere, and the reaction formula (10) The 2O generated in 10) becomes oxygen gas O ₂ as shown in the above reaction formula (11). The nitrogen gas N ₂ and the oxygen gas O ₂ are chemically stable and harmless gases.

The reaction of the above reaction formulas (10) and (11)
If so, the second valve 24 is opened and the container 13 is opened.
Chisso gas N_TwoAnd oxygen gas O_TwoTo the outside (arrow
Mark B). As a result, the harmful effects in the exhaust gas from the engine
NO is harmless nitrogen N _TwoAnd oxygen gas O_TwoDecomposed into
It is.

This gas decomposition apparatus has the following advantages. First, since the decomposition of the gas is performed in a reducing atmosphere or a substantially reducing atmosphere, the HN
O ₃ is not generated, so there is no need to add a neutralizing agent such as ammonia to treat it with ammonium nitrate. Second, since the gas is substantially confined by adsorbing the gas onto the adsorbent 14 in the container and a reaction such as a radical reaction is performed as a batch method (ie, the gas is continuously flowed as in the above-described conventional method). Therefore, the gas concentration in the container is increased, and a large amount of gas can be decomposed by efficiently performing a reaction such as a radical reaction. However, it is not prohibited to generate a radical reaction in the container 13 while the first valve 23 and the second valve 24 are kept open. However, in this case, external air enters the container 13 to reduce it. It is desirable to avoid such an operation method because the atmosphere is reduced and the gas concentration in the container 13 is reduced to lower the radical reaction efficiency.

[Sixth Embodiment] Next, an application example of the gas decomposition apparatus shown in FIG. 7 will be described with reference to FIG. FIG. 8 is a configuration diagram showing a combination of a plurality of gas decomposition apparatuses according to the fifth embodiment of the present invention. As shown in FIG.
Two gas decomposition units 10A and 10B are provided in parallel, and the first pipe 21 is connected to the engine 28. The same elements as those in FIG. 1 are denoted by the same reference numerals. The apparatus shown in FIG. 7 includes two disassembly units 10 shown in FIG.
These are combined in parallel.

Next, the operation will be described. As shown in FIG.
Since this gas decomposing device is provided with two decomposing units 10A and 10B, it is desirable that the two gas decomposing units 10A and 10B alternately decompose the gas described above.
That is, when the first valve 23 on one decomposition unit 10A side is closed and the switch S1 is closed to supply a voltage to cause a radical reaction or the like in the decomposition unit 10A, the second valve 23 on the other decomposition unit 10B side is generated. One valve 23
Is opened, and the switch S2 is opened to supply exhaust gas from the engine 28 to the decomposition unit 10B. When the radical reaction or the like of one of the decomposition units 10A is completed and nitrogen gas N ₂ and oxygen gas O ₂ are discharged from the second pipe 22, or when the next exhaust gas is supplied from the engine 28 to the decomposition unit 10A , The switch S1 is opened, the switch S2 is closed, and the disassembly unit 1
A voltage is applied to the first electrode 11 of OB to generate a radical reaction.

If two decomposition units are provided in this manner, and the two decomposition units sequentially or alternately decompose the gas, the resolution rate can be significantly increased.
Of course, also in this case, preferably, the reducing gas is supplied from the reducing gas supply means 27 to each of the decomposition units. Of course, the radical reaction may be performed in parallel by the two decomposition units, and the operation method can be freely determined. In addition, three or more disassembly units may be provided, and in this case, the above-described processing can be performed alternately or sequentially in each disassembly unit, and further arbitrarily in parallel. As the type of the adsorbent, one having good adsorbability of the gas is selected and used according to the type of the gas to be decomposed.

[Seventh Embodiment] FIG. 9 shows a seventh embodiment of the present invention.
It is a lineblock diagram of a gas decomposition device of an embodiment. This disassembly unit 10C also includes a first electrode 11C and a second electrode 12C.
C, a container 13C is disposed between the two adsorbents 14A, 14B, 14C.
Is stored. These adsorbents 14A, 14B, 1
4C has different adsorption characteristics, and adsorbs different gases well. These adsorbents 14A, 14B, and 14C may be mixed, but the interior of the container 13C is partitioned by the air-permeable partition 29 as in the present embodiment, and the first chamber is provided in each partitioned chamber.
Adsorbent 14A, second adsorbent 14B, third adsorbent 1
It is desirable to store 4C separately from the viewpoint of handling management. The same elements as those in the above embodiments are denoted by the same reference numerals.

In this embodiment, the first adsorbent 14A is made of NO _X
The second adsorbent 14B is a VOC adsorbent, and the third adsorbent 14C is an adsorbent of another arbitrary gas. The plasma processing method of the present embodiment is the same as that of the first embodiment, but as described above, a plurality of types of adsorbents 14A and 14A are used.
By providing B and 14C, plasma processing of a mixed gas in which a plurality of types of gases are mixed can be performed at a time. Of course, a plurality of the decomposition units shown in FIG. 1 may be connected in series by a pipe or the like to perform the decomposition of the composite gas at a time. As described above, various design changes can be made to the disposition specifications and the structure of the disassembly unit and the adsorbent.

In the above configuration, a potential difference is applied between the first electrode and the second electrode in a state where the gas to be decomposed is adsorbed on the adsorbent, and the gas is decomposed by performing a plasma treatment. In this case, when the O ₂ concentration is originally low, external air hardly enters the inside and the surface of the adsorbent.
The inner surface of the adsorbent is almost kept in a reducing atmosphere containing little oxygen, and the gas is decomposed in this reducing atmosphere state. Thus, for example, if the gas is a low O ₂ gas, such as the exhaust gas of a gasoline engine, the gas will be exclusively decomposed into harmless N ₂ and O ₂ in a reducing atmosphere. In addition, dioxin, VO
C, ethylene and the like have a high O ₂ , and when there is a relatively large amount of O ₂ near the surface of the adsorbent, H ₂ O, CO ₂ , H
It can be converted to Cl or the like.

Further, a gas is sent to the adsorbent, the gas adsorbed on the adsorbent is decomposed by plasma treatment, and the decomposed gas is discharged from the adsorbent. If the treatment is performed, batch-type plasma treatment becomes possible, and the gas concentration can be increased as compared with the conventional plasma treatment performed while continuously flowing the gas, so that the amount of decomposition of the gas is increased accordingly. And efficient decomposition processing can be performed.

[0072]

As described above, according to the first aspect of the present invention, there is provided an adsorbent for adsorbing a harmful substance and decomposing the adsorbed substance by a plasma treatment. , It is possible to control the plasma generation location.

According to the second aspect of the present invention, since the relative dielectric constant of the ferroelectric is 1000 or more and the relative dielectric constant of the adsorbent is 1 to 20, the plasma generation location is further controlled. be able to.

According to the third aspect of the present invention, since the macropore of the adsorbent is 4 to 100 μm, the location of plasma generation can be further controlled in the macropore.

According to the invention of claim 4, the first electrode and the second electrode, a potential difference applying means for applying a potential difference between the first electrode and the second electrode, A harmful substance is adsorbed by being disposed between the first electrode and the second electrode.
And a plasma processing container accommodating the adsorbents of (1) to (3), and by applying a potential difference between the first electrode and the second electrode, the harmful substance adsorbed by the adsorbent is removed from the inside of the adsorbent. Since it decomposes on the surface and in the vicinity, it is possible to adsorb the decomposition of harmful substances in the exhaust gas with an adsorbent to make the gas concentration substantially high and raise the gas concentration, and to generate radical reactions etc. in that state. As a result, the gas decomposition ability can be significantly increased and efficient gas decomposition can be performed.

According to the invention of claim 5, the first electrode and the second electrode, a commercial frequency high voltage power supply for applying a high voltage between the first electrode and the second electrode, A high voltage pulse power supply for superimposing a high voltage pulse on the commercial frequency high voltage,
4. A plasma processing container for accommodating an adsorbent according to claim 1, which is disposed between said first electrode and said second electrode and adsorbs harmful substances. By applying a potential difference between the electrodes, the harmful substance adsorbed by the adsorbent is decomposed inside, on the surface of the adsorbent and in the vicinity thereof, so that a pulse is applied from a high-voltage pulse power supply having the same polarity as the commercial frequency. As a result, electrons are accelerated from the left and right directions of the adsorbent, and as a result, radical generation efficiency is drastically improved over the entire surface of the adsorbent, and power consumption can be reduced.

According to the invention of claim 6, the adsorbent contained in the plasma processing apparatus satisfies the following formulas (1) and (2), and is selected in the vicinity of the adsorbent surface and in the macropore inside the adsorbent. Since the electric field is applied, the location where the plasma is generated can be further controlled. 0 ≦ k1 ≦ 1 (1) 0.5 ≦ k2 ≦ 0.9 (2) where k1 = gap distance (dg) between adsorbents /
Adsorbent thickness (da) k2 = ferroelectric diameter (φs) / adsorbent diameter (φa).

According to the seventh aspect of the present invention, the spacer is accommodated together with the adsorbent accommodated in the plasma processing apparatus, and the expressions (1) and (2) are satisfied. Can be.

According to the eighth aspect of the present invention, since the spacer carries a photocatalyst, a synergistic effect is achieved by decomposition by the photocatalyst together with plasma decomposition.

According to a ninth aspect of the present invention, a plurality of the decomposing devices according to the fourth or fifth aspect are provided, and the gas supply means for supplying exhaust gas to the adsorbent of each decomposing device and the decomposed from the adsorbent are provided. Since the gas discharging means for discharging the gas is provided, if the gas is decomposed sequentially or alternately by a plurality of decomposition units, the resolution rate can be remarkably increased.

According to the tenth aspect of the present invention, since the reducing gas supply means for supplying the reducing gas is provided in the plasma processing vessel, efficient decomposition in a reducing atmosphere can be performed.

According to the eleventh aspect, the harmful substances can efficiently decompose exhaust gas discharged from an incinerator, a pyrolysis furnace, a melting furnace, or the like.

According to the invention of claim 12, the harmful substance in the exhaust gas is at least one selected from dioxins, polyhalogenated biphenyls, halogenated benzenes, halogenated phenols and halogenated toluenes. Can degrade halogenated aromatic compounds, highly condensed aromatic hydrocarbons and environmental hormones.

According to the invention of claim 13, the incinerator,
An exhaust gas treatment device for purifying exhaust gas discharged from a pyrolysis furnace, a melting furnace, etc., comprising a dust removal device for removing dust in the exhaust gas, and a harmful substance decomposition device provided downstream of the dust removal device. Therefore, harmful substances in the exhaust gas can be efficiently decomposed.

According to the fourteenth aspect, a harmful substance is supplied to the adsorbent according to any one of the first to third aspects disposed between the first electrode and the second electrode, and the harmful substance is supplied to the adsorbent. The substance is adsorbed, and the first electrode and the second
By applying a potential difference between the electrodes, the harmful substances adsorbed by the adsorbent are decomposed inside and on the surface of the adsorbent and in the vicinity thereof. Since it is possible to raise the gas concentration in a closed state and generate a radical reaction or the like in that state, the gas decomposition ability can be remarkably increased and efficient gas decomposition can be performed.

According to the invention of claim 15, the first electrode and the second electrode, the potential difference applying means for applying a potential difference between the first electrode and the second electrode, and the first electrode A plurality of plasma processing vessels comprising the adsorbent according to any one of claims 1 to 3, which are disposed between the first electrode and the second electrode and adsorb harmful substances, and wherein each of the plasma processing vessels has a plurality of plasma processing vessels. Harmful substance supply means for supplying harmful substances to the adsorbent according to 3,
A method for decomposing harmful substances by a harmful substance decomposition apparatus provided with harmful substance discharge means for discharging harmful substances from the adsorbent, wherein the harmful substances are supplied to the adsorbents in the respective plasma processing vessels. Decomposes the harmful substances adsorbed by the adsorbent, so that the decomposition of the harmful substances in the exhaust gas is adsorbed by the adsorbent so that the gas density is increased in a substantially sealed state, and a radical reaction or the like occurs in that state. Because it is possible
The efficiency of gas decomposition can be increased by significantly increasing the gas decomposition ability.

According to the invention of [claim 16], claim 1 is provided.
In 4 or 15, since plasma decomposition is performed in a reducing gas atmosphere, harmful substances can be decomposed in a reducing atmosphere, and the gas concentration is increased in a substantially sealed state, and radical reactions and the like are performed in that state. Can be generated, so that the gas decomposing ability can be remarkably increased and efficient gas decomposition can be performed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an adsorbent according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a gas decomposition apparatus according to the first embodiment of the present invention.

FIG. 3 is a configuration diagram of an adsorbent according to the first embodiment of the present invention.

FIG. 4 is a configuration diagram of an adsorbent according to a second embodiment of the present invention.

FIG. 5 is a configuration diagram of an adsorbent according to a third embodiment of the present invention.

FIG. 6 is a configuration diagram of an adsorbent according to a fourth embodiment of the present invention.

FIG. 7 is a configuration diagram of a gas decomposition apparatus according to a fifth embodiment of the present invention.

FIG. 8 is a configuration diagram of a gas decomposition apparatus according to a sixth embodiment of the present invention.

FIG. 9 is a configuration diagram of a gas decomposition apparatus according to a seventh embodiment of the present invention.

FIG. 10 is a configuration diagram of a conventional gas decomposition apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 100 Adsorbent for plasma processing 101 Adsorbent 102 Ferroelectric 104 Spacer 110 Decomposition device of harmful substance 111 First electrode 112 Second electrode 113 Potential difference applying means 114 Plasma processing container 121 First electrode 122 Second electrode 123 Commercial frequency high voltage power supply 124 High voltage pulse power supply 10 Gas decomposition unit 11 First electrode 12 Second electrode 13 Vessel 14, 14A, 14B, 14C Adsorbent 15 Power supply 21 First pipe 22 Second pipe 23 1 valve 24 second valve 25 third pipe 26 third valve 27 reducing gas supply means

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Akinori Yasutake 5-717-1 Fukahori-cho, Nagasaki-shi, Nagasaki Sanishi Heavy Industries Co., Ltd. No. 717-1 F-term in Nagasaki Laboratory, Mitsubishi Heavy Industries, Ltd. (Reference) 4D002 AA12 AA17 AA21 AA33 AA40 AB03 AC04 AC07 AC10 BA04 CA07 CA13 DA45 DA46 GB12 HA01 4G066 AA30B AA61B BA20 BA22 BA23 BA50 CA01 CA04 CA28 CA33 CA51 DA02

Claims (16)

[Claims] 1. An adsorbent for adsorbing a harmful substance and decomposing the adsorbed substance by plasma treatment, wherein a ferroelectric substance is disposed inside the adsorbent, the adsorbent for plasma treatment being used. 2. The adsorbent for plasma processing according to claim 1, wherein the ferroelectric has a relative dielectric constant of 1000 or more, and the adsorbent has a relative dielectric constant of 1 to 20. 3. The adsorbent according to claim 1, wherein the adsorbent has a macropore of 4 to 100 μm. 4. A first electrode and a second electrode, potential difference applying means for applying a potential difference between the first electrode and the second electrode, and a potential difference applying means between the first electrode and the second electrode. And a plasma processing container that accommodates the adsorbent according to any one of claims 1 to 3, wherein the plasma processing container accommodates the adsorbent according to any one of claims 1 to 3, and applies a potential difference between the first electrode and the second electrode. Thereby decomposing the harmful substance adsorbed by the adsorbent on the inside, on the surface and in the vicinity of the adsorbent. 5. A first electrode and a second electrode, a commercial frequency high voltage power supply for applying a high voltage between the first electrode and the second electrode, and a high voltage pulse applied to the commercial frequency high voltage. And a high-voltage pulse power supply for superimposing the first and second electrodes, and a plasma processing container containing the adsorbent according to any one of claims 1 to 3, which adsorbs harmful substances. And by applying a potential difference between the first electrode and the second electrode, harmful substances adsorbed by the adsorbent are decomposed inside, on the surface of the adsorbent, and in the vicinity thereof. Harmful substance decomposition equipment. 6. The adsorbent according to claim 4, wherein the adsorbent contained in the plasma processing apparatus is represented by the following formula (1):
An apparatus for decomposing harmful substances, which satisfies (2) and selectively applies an electric field in the vicinity of the surface of the adsorbent and in the macropores inside the adsorbent. 0 ≦ k1 ≦ 1 (1) 0.5 ≦ k2 ≦ 0.9 (2) where k1 = gap distance (dg) between adsorbents /
Adsorbent thickness (da) k2 = ferroelectric diameter (φs) / adsorbent diameter (φa). 7. An apparatus for decomposing harmful substances according to claim 6, wherein a spacer is housed together with the adsorbent housed in the plasma processing apparatus, and the expressions (1) and (2) are satisfied. 8. The apparatus for decomposing harmful substances according to claim 7, wherein the spacer carries a photocatalyst. 9. A gas supply means for supplying a plurality of decomposition devices according to claim 4 or 5 and supplying exhaust gas to an adsorbent of each decomposition device and a gas discharging means for discharging decomposed gas from the adsorbent. An apparatus for decomposing harmful substances. 10. An apparatus for decomposing harmful substances according to claim 4, further comprising a reducing gas supply means for supplying a reducing gas into the plasma processing vessel. 11. The apparatus for decomposing harmful substances according to claim 4, wherein the harmful substances are exhaust gases discharged from an incinerator, a pyrolysis furnace, a melting furnace, or the like. 12. The method according to claim 11, wherein the harmful substance in the exhaust gas is at least one halogenated aromatic selected from dioxins, polyhalogenated biphenyls, halogenated benzenes, halogenated phenols and halogenated toluenes. A device for decomposing harmful substances, which is a compound, a highly condensed aromatic hydrocarbon or an environmental hormone. 13. An exhaust gas treatment device for purifying exhaust gas discharged from an incinerator, a pyrolysis furnace, a melting furnace, or the like, comprising: a dust removal device for removing dust in the exhaust gas; and a dust removal device provided downstream of the dust removal device. An exhaust gas treatment apparatus comprising the harmful substance decomposition apparatus according to any one of claims 4 to 11. 14. A harmful substance is supplied to the adsorbent according to claim 1 disposed between the first electrode and the second electrode, and the harmful substance is adsorbed on the adsorbent. By applying a potential difference between the first electrode and the second electrode by the potential difference applying means in that state, it is possible to decompose harmful substances adsorbed by the adsorbent on the inside, on the surface of the adsorbent and in the vicinity thereof. Characteristic method of decomposing harmful substances. 15. A first electrode and a second electrode, a potential difference providing means for providing a potential difference between the first electrode and the second electrode, and a potential difference providing means for providing a potential difference between the first electrode and the second electrode. 4. A plurality of plasma processing vessels comprising the adsorbent according to any one of claims 1 to 3, which are arranged in a plasma processing vessel and adsorb harmful substances, and in each of the plasma processing vessels. A method for decomposing harmful substances by a harmful substance decomposition apparatus provided with harmful substance supply means for supplying harmful substances to the harmful substance, and harmful substance discharge means for discharging harmful substances from the adsorbent, comprising: A method for decomposing harmful substances, characterized in that harmful substances are supplied to the adsorbents and the harmful substances adsorbed on the respective adsorbents are decomposed. 16. The method for decomposing harmful substances according to claim 14 or 15, wherein plasma decomposition is performed in a reducing gas atmosphere.