JP2002361044A - Method for treating waste gas and liquid chemicals - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for treating waste gas and liquid chemicals by which the emission of dioxins into the environment can extreamely be suppressed. SOLUTION: In a wet scrubbing tower 1 in which liquid chemicals are sprayed on waste gas containing acidic components and organic halogen compounds such as dioxins to chiefly remove the acidic components, at least part of the liquid chemicals circulated and sprayed through the absorption of the acidic components is fed to an organic halogen compound removing unit 7, freed of the organic halogen compounds, circulated and sprayed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for treating an exhaust gas containing an acidic component and an organic halogen compound such as dioxin discharged from various operations such as incineration, heating and melting, and a chemical solution circulated and sprayed in a wet washing tower. In the processing method.

[0002]

2. Description of the Related Art HCl contained in exhaust gas from incinerators and the like
And as one of the processing method of the acidic components such as SO _X, conventionally wet scrubber for spraying the aqueous solution of sodium hydroxide has been employed. At the same time, dry treatment in which slaked lime powder is sprayed and reactive dust is collected by a bag filter is also often used, but when highly acidic components are removed, wet treatment can be said to be superior.

FIG. 4 is an explanatory diagram showing an example of a conventional exhaust gas treatment method. Exhaust gas containing acidic components discharged from incinerators, boilers, and other exhaust gas generators is cooled and dust-collected, and then introduced into the wet washing tower 21 via the introduction duct 24. The exhaust gas introduced into the wet washing tower 21 is sprayed with a chemical solution such as an aqueous solution of caustic soda in a lower chemical liquid spraying section 22, and then to a dehumidifying section 23 including an upper mist separator and a dehumidifying water spray pipe. It is cooled by the dehumidified water introduced and circulated and used to remove water in the exhaust gas to some extent. Exhaust gas that has passed through the dehumidifying section 23 is discharged out of the system through a discharge duct 25, reheated as necessary, and then discharged from a chimney.

A caustic soda aqueous solution, which is a chemical sprayed in the wet washing tower 21, is often circulated and sprayed using a circulation pump 26 or the like for effective use. Salts), heavy metals, and fine suspended substances (hereinafter referred to as SS). For this reason, the unreacted material decreases with time, so that a fresh caustic soda aqueous solution according to the reaction amount is appropriately replenished to the spray solution, and at the same time, a part of the chemical solution collected from the bottom of the wet washing tower 21 is extracted and separately added. It had been introduced into a wastewater treatment tank.

In recent studies, exhaust gases containing dioxins (organic halogen compounds) and various wastewaters that may come into contact with fly ash have a relatively low concentration level but contain dioxins. It has been known. Also in the above-mentioned wet type washing tower 21, dioxins are contained in exhaust gas and soot and dust (fly ash) in the exhaust gas, and the sprayed chemical liquid comes into contact with them, so that the dioxin is also contained in the circulating sprayed chemical liquid. I was On the other hand, in order to reduce dioxins in exhaust gas, a method of spraying activated carbon upstream of the wet washing tower 21 and adsorbing and removing dioxins in the tower has been partially implemented.

[0006]

However, in the conventional wet cleaning tower 21, although a part is introduced into the wastewater treatment tank, the chemical solution is circulated and sprayed. Dioxins tend to be concentrated, and the concentration of dioxins undesirably increases. Furthermore, when the dioxin concentration of the chemical solution to be circulated and sprayed increases, if the dioxin concentration in the exhaust gas is relatively low, dioxins are transferred from the sprayed chemical solution to the exhaust gas, and as a result, the dioxin concentration in the exhaust gas increases. Such a problem also occurs.

On the other hand, in the above-mentioned method of reducing dioxins in exhaust gas by spraying activated carbon into the exhaust gas,
Since a considerable amount of dioxins is adsorbed on the activated carbon in the chemical solution, the concentration of dioxins undesirably rises in the process of circulating spray of the chemical solution as well, and the risk of dioxins being transferred to exhaust gas more than the above is reduced. Will happen. In addition, the activated carbon used to adsorb dioxins in exhaust gas has a reduced (saturated) adsorption capacity in the process of circulating spray, and when the dioxin concentration in the exhaust gas is high, the ability of activated carbon to adsorb dioxin cannot be expected. Problems also occur.

The present invention has been made in order to solve these problems, and provides a method for treating exhaust gas and a chemical solution capable of remarkably reducing the release of dioxins (organic halogen compounds) into the environment. It is intended for.

[0009]

The method for treating exhaust gas and chemicals according to the present invention is as follows. (1) In a wet cleaning tower for spraying a chemical solution onto an exhaust gas containing an acidic component and an organic halogen compound such as dioxin to mainly remove the acidic component contained in the exhaust gas, circulating spray through absorption of the acidic component in the exhaust gas At least a part of the chemical solution is passed through an organic halogen compound removing device to remove the organic halogen compound in the chemical solution, and then is subjected to circulation spraying.

As described above, at least a part of the chemical solution such as the aqueous solution of caustic soda to be circulated and sprayed is circulated to the organic halogen compound removing device (dioxin removing device) and then subjected to the circulating spray, so that it is accumulated at the bottom of the washing tower. The undesired increase in the dioxin concentration of the chemical solution to be performed does not occur.
In addition, since the dioxin concentration in the chemical solution sprayed by circulation is extremely low, the problem of dioxin in the chemical solution being reversely transferred to exhaust gas is prevented beforehand, and the dioxin concentration in exhaust gas is not increased, so that the effect on pollution prevention is prevented. (The dioxin concentration in the exhaust gas released to the atmospheric environment can be safely managed.)

(2) The organic halogen compound removing device of the above (1) is a coagulation sedimentation device, a sand filtration device, a membrane filtration device,
It consisted of at least one device selected from an adsorbent filling device, a catalytic decomposition device, an electrolysis device, an ultraviolet irradiation device, a microwave irradiation device, and an ozone treatment device.

Chemical solution to be sprayed in circulation (equivalent to the chemical solution at the bottom of the tower)
Most of the dioxins contained therein are mainly composed of fine solids (hereinafter, referred to as SS), and the amount of soluble dioxins is relatively small. Therefore, first, it is desirable to remove fine SS content in the chemical solution by using one device selected from a coagulation sedimentation device, a sand filtration device, a membrane filtration device, and an adsorbent filling device. An activated carbon having predetermined pores or the like is selected as the adsorbent filling device, and is effective in removing soluble dioxins as well as removing SS. In order to remove soluble dioxins as well as dioxins derived from SS, as a dioxin decomposing device, a device based on various principles such as a catalytic decomposition device, an electrolysis device, an ultraviolet irradiation device, a microwave irradiation device, and an ozone treatment device is selected. It is. A plurality of these devices can be combined, and the effects thereof are synergistic, and the operation can be further ensured. Thus, the operation according to the above (1) can be made more reliable.

(3) A powder adsorbent is sprayed on the exhaust gas before being introduced into the wet cleaning tower of the above (1) or (2) or on the exhaust gas in the wet cleaning tower to remove the organic halogen compound contained in the exhaust gas. It is adsorbed by the adsorbent and separated from exhaust gas.

As described above, for example, activated carbon powder as a powder adsorbent is sprayed into an exhaust gas before being introduced into a wet washing tower, for example, into a duct coming out of a dust collector provided in advance, or powder is introduced into a wet washing tower. By spraying as it is, organic halogen compounds such as dioxin contained in exhaust gas can be effectively adsorbed and removed. The sprayed activated carbon powder is suspended as a slurry in the chemical solution to be circulated and sprayed. However, as described in the above (1) or (2), at least a part of the chemical solution to be circulated and sprayed is circulated to the dioxin removing device. The effect of reducing the dioxin concentration in the chemical solution and not increasing the dioxin concentration in the exhaust gas can be obtained in the same manner as in (1) or (2).

(4) A powder adsorbent or a slurry-type adsorbent is mixed with the chemical sprayed in the wet washing tower according to the above (1) or (2), and the organic liquid contained in the exhaust gas in the process of spraying the chemical mixed with the adsorbent is mixed. In this method, a halogen compound is adsorbed by the adsorbent and separated from exhaust gas.

As described above, a powder adsorbent or a slurry-type adsorbent is mixed into a chemical solution to form an activated carbon suspension (slurry). Therefore, in the process of spraying the chemical solution onto the exhaust gas, dioxins in the exhaust gas are converted into the above (3). ) Can be effectively adsorbed and removed. In addition, an operation equivalent to the above (1) or (2) is obtained.

[0017]

[First Embodiment] FIG. 1 is an explanatory view showing a method for treating an exhaust gas and a chemical solution according to a first embodiment of the present invention. 1 is a wet washing tower (main body), 2 is a chemical spraying section (chemical containing tank), 3 is a dehumidifying section, 4 is an introduction duct, and 5 is a discharge duct. 6 is a circulation pump for chemicals, 7 is an organic halogen compound removing device (dioxin removing device), 10
Is a fresh chemical supply device, and A is a flow control valve. In these drawings, detailed devices are omitted for convenience of explanation.

Exhaust gas containing acidic components discharged from an incinerator, a boiler, and other exhaust gas generators (not shown) is cooled appropriately, then subjected to a dust collection process using, for example, a bag filter device. 1 through an introduction duct 4. The exhaust gas introduced into the wet washing tower 1 is sprayed with a chemical such as a caustic soda aqueous solution in a lower chemical liquid spraying section 2 and then into a dehumidifying section 3 composed of an upper mist separator, a dehumidifying water spray pipe and the like. The moisture in the exhaust gas is removed to some extent by being cooled by the introduced and circulated dehumidified water. The exhaust gas that has passed through the dehumidifying section 3 is discharged out of the system through the discharge duct 5 and, if necessary, reheated, and then discharged from the chimney.

Next, in the spraying of the chemical solution (caustic soda aqueous solution), the unused caustic soda aqueous solution joins the chemical solution circulation line from the chemical solution supply device 10 and sprays the inside of the wet washing tower 1. Although not shown, the spraying means uses a spray tube having a large number of holes or a spray nozzle. The spray amount of the unused aqueous solution of caustic soda is determined by calculating from the amount of acidic component to be treated per unit time and multiplying by a safety factor, or is determined so as to maintain the pH of the bottom chemical solution tank at, for example, about 8. Or by controlling the concentration of the acidic component at the outlet.

The sprayed caustic soda aqueous solution comes into contact with the exhaust gas in the wet washing tower 1, and in the course of the contact, the HC in the exhaust gas
1, a neutralization reaction with acidic components such as SO _X removes these acidic components. The sprayed caustic soda aqueous solution is formed at the bottom of the chemical spraying section 2 as a chemical bath containing a reaction product. Then, an aqueous caustic soda solution containing a reaction product is extracted from the chemical solution tank by a circulation pump 6, and at least a part thereof is removed from an organic halogen compound (dioxin) removing device 7
To remove dioxins in the chemical solution. The introduction amount is determined by the flow control valve A.

The chemical solution (caustic soda aqueous solution containing the reaction product) which has passed through the organic halogen compound removing device 7 is sprayed into the wet washing tower 1 (chemical solution spraying section 2) by the spraying means and stored at the bottom, as described above. A part thereof is withdrawn again by the circulation pump 6 and provided for circulation spraying. The chemical liquid in the chemical liquid tank at the bottom (partially provided for the circulating spray and dioxin removing device) contains unreacted caustic soda, reaction products (such as NaCl), heavy metals, dioxins (organic halogen compounds), and SS. I do.

As described above, after at least a part of the chemical solution such as the aqueous solution of caustic soda to be circulated and sprayed is passed through the organic halogen compound removing device (dioxin removing device) 7,
Since it is subjected to circulation spraying, the concentration of dioxin in the chemical solution (chemical solution tank) accumulated at the bottom of the wet washing tower 1 does not undesirably increase. In addition, the dioxin concentration in the chemical sprayed by circulation is extremely low, which prevents the dioxin in the chemical from reversely migrating to the exhaust gas and prevents the concentration of dioxin in the exhaust gas from increasing, thus preventing pollution. (The dioxin concentration in the exhaust gas released to the atmospheric environment can be safely managed.)

Here, the organic halogen compound removing device 7
Uses at least one device selected from a coagulation sedimentation device, a sand filtration device, a membrane filtration device, an adsorbent filling device, a catalyst decomposition device, an electrolysis device, an ultraviolet irradiation device, a microwave irradiation device, and an ozone treatment device. Is preferred.

The dioxins in the chemical solution to be sprayed in circulation (equivalent to the chemical solution at the bottom of the wet cleaning tower 1) are mostly composed of fine solids (SS), and the soluble dioxins are relatively small. In case of advanced processing, it cannot be ignored. Therefore, first, coagulation sedimentation equipment, sand filtration equipment,
By means selected from membrane filtration device and adsorbent filling device,
It is desirable to remove fine SS components in the chemical solution. An activated carbon having predetermined pores or the like is selected as the adsorbent filling device, and is effective in removing soluble dioxins as well as removing SS. In order to remove soluble dioxins as well as dioxins derived from SS, as a dioxin decomposing device, a device based on various principles such as a catalytic decomposition device, an electrolysis device, an ultraviolet irradiation device, a microwave irradiation device, and an ozone treatment device is selected. It is. A plurality of these devices can be combined, the effects of which are synergistic, and the effect of the invention described in (2) of the means for solving the above problems can be further ensured. The operation of the invention described in the above (1) can be made more reliable.

The coagulation sedimentation apparatus uses a coagulant such as a sulfuric acid band or ferric chloride, and if necessary, performs a pH treatment in advance to mainly remove fine suspended solids (SS) in the dehumidified water. The sand filtration device is a filtration device filled with silica sand or the like having a predetermined particle size, and mainly removes SS. The membrane filtration device uses a precisely adjusted membrane for water filtration, and performs backwashing as necessary. Mainly, the SS component containing a large amount of dioxin is removed. However, dissolving dioxin can be removed by supporting a catalyst function, an adsorption function, and an oxidation function on the membrane.
In the adsorbent filling apparatus, activated carbon having predetermined pores or the like is selected, and the treated water is allowed to flow through the layer filled with the activated carbon to remove SS and remove soluble dioxins.

The electrolyzer decomposes the SS-derived and soluble dioxin by immersing a plurality of electrodes in a tank and using an electrolysis action when energizing. The UV irradiator is equipped with a UV generating mechanism in the tank, and directly irradiates the wastewater
Decomposes S-derived and soluble dioxins. The microwave irradiator is configured to emit a microwave having a predetermined wavelength (for example, 2.4
(5 GHz) is provided in the tank, and the wastewater is directly irradiated to decompose SS-derived and soluble dioxins.
The ozone decomposing device decomposes SS-derived and soluble dioxin mainly by accelerating oxidation by installing an ozone generator in a water tank and flowing ozone through the water tank.
These various dioxin removing devices 7 incorporate various control devices for controlling the temperature, pressure, power, pH, and processing amount as appropriate. Further, in order to increase the dioxin removal effect, a plurality of these devices can be combined.

[Second Embodiment] FIG. 2 is an explanatory view showing an exhaust gas treatment method according to a second embodiment of the present invention. The same parts as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. In the present embodiment, an activated carbon powder supply device 8 is added to the configuration of the first embodiment. In addition, a and b are supply lines of activated carbon powder.

Activated carbon is introduced into the activated carbon powder supply device 8 from a storage tank of activated carbon (not shown) as an adsorbent, and the supply means of the activated carbon powder supply device 8 introduces the activated duct 4 into the wet washing tower 1.
Activated carbon powder is blown into the flue. The a line in the figure indicates this. The b line in the figure indicates that the activated carbon powder was directly sprayed on the wet cleaning tower main body 1. The effect of adsorbing dioxin in exhaust gas is almost the same for both the supply lines a and b. The sprayed activated carbon powder is wet by the spraying action of the chemical solution in the wet washing tower 1 and is mixed into the chemical solution tank at the bottom. As a result, the activated carbon suspension (unreacted chemical solution, reaction product, heavy metal,
Dioxins, SS, etc.).

As described above, for example, activated carbon powder is sprayed as a powder adsorbent into an exhaust gas before the activated carbon powder is introduced into the wet washing tower 1, for example, into a duct (in the above description, the introduction duct 4) exiting a dust collector provided in front. Alternatively, by spraying the powder as it is into the wet washing tower 1, organic halogen compounds such as dioxin contained in the exhaust gas can be effectively adsorbed and removed. The sprayed activated carbon powder is suspended as a slurry in the chemical solution to be circulated and sprayed. As described in (1) or (2) of the means for solving the above problem, at least a part of the chemical solution to be circulated and sprayed is dispersed. , The dioxin concentration in the chemical solution can be reduced and the effect of not increasing the dioxin concentration in the exhaust gas can be obtained in the same manner as in the above (1) or (2).

[Third Embodiment] FIG. 3 is an explanatory view showing an exhaust gas treatment method according to a third embodiment of the present invention. The same parts as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. In the present embodiment, a supply device 9 for an activated carbon slurry (suspension solution) is added to the configuration of the first embodiment. Here, c and d are activated carbon slurry supply lines.

Activated carbon slurry is introduced from a storage tank (not shown) of activated carbon, which is an adsorbent, into an activated carbon slurry supply device 9 via an activated carbon slurry tank (not shown). Let it. The line c in the figure indicates this. In this case, the activated carbon before mixing may be powdered. The d line in the figure indicates that the activated carbon slurry is directly sprayed on the wet cleaning tower main body 1.
In both cases of the activated carbon slurry supply lines c and d, the effect of adsorbing dioxin in exhaust gas is almost the same. The sprayed activated carbon slurry accumulates on the bottom together with the chemical, resulting in an activated carbon suspension (including unreacted chemical, reaction products, heavy metals, dioxins, SS, etc.).

As described above, the powder adsorbent or the slurry-like adsorbent is mixed into the chemical liquid to form an activated carbon suspension (slurry). Therefore, in the process of spraying the chemical liquid onto the exhaust gas, dioxins in the exhaust gas are used. Adsorption and removal can be performed as effectively as in the case of the embodiment 2 (FIG. 2). Further, the operation described in (1) or (2) of the means for solving the above problem (the operation in FIG. 1) can be obtained equivalently.

The dehumidifying section 3 of the wet washing tower 1 according to the present invention comprises:
For example, a mist (dehumidifying water) removing means such as a mist separator and an eliminator, a dehumidifying water spraying means, a dehumidifying water cooling means, a dehumidifying water circulating means, etc., are not limited thereto. The wet cleaning tower 1 which is a constituent element of the present invention exemplifies a caustic soda aqueous solution (NaOH) as a chemical solution.
Not limited to this, an alkaline agent capable of removing acidic components, can be employed as long as it can be a suspension with a water soluble or water, in addition to examples of NaOH, for example, Na ₂ CO
₃ , NaHCO ₃ , Ca (OH) ₂ , etc. may be used. In addition, a method of installing a small preliminary washing tower immediately before the wet washing tower 1, spraying a chemical solution equally, and mixing the bottom waste liquid from the tower into the wet washing tower 1 is often adopted.
The description is omitted in this specification.

The present invention is applicable to any facility that treats exhaust gas discharged from various operations such as incineration, heating and melting and containing harmful components such as acidic components and dioxins by at least a wet method, and is not limited to the above. .

The above-mentioned organic halogen compounds contained in the exhaust gas and the chemical solution (smoke washing wastewater) are dioxins in which emission control values and environmental control values of wastewater incineration plants are specified by toxicity conversion values by the Ministry of Health, Labor and Welfare and the Ministry of the Environment. Is a general term for chlorobenzene, chlorophenol, PCB, and the like, which are called precursors and related substances of dioxins, and those chemical substances partially substituted with a halogen element other than chlorine. Further, dioxins are a general term for polydibenzoparadioxin and polydibenzofuran, and are usually evaluated based on toxic equivalent concentrations. In this specification, it is added that the above-mentioned organic halogen compounds and dioxins may be simply abbreviated as dioxin.

[0036]

(1) The present invention relates to a wet cleaning tower for spraying a chemical solution onto an exhaust gas containing an acidic component and an organic halogen compound such as dioxin to mainly remove the acidic component contained in the exhaust gas. Since at least a part of the chemical solution that is circulated and sprayed through the absorption of the acidic component therein is passed through an organic halogen compound removing device to remove the organic halogen compound in the chemical solution, and then subjected to circulation spraying, the washing tower is used. An effect is obtained in which the concentration of dioxin in the chemical solution accumulated at the bottom does not undesirably increase. In addition, since the concentration of dioxin in the chemical sprayed by circulation is extremely low,
Prevents the problem that dioxin in chemical solution is transferred back to exhaust gas beforehand, and does not increase the concentration of dioxin in exhaust gas, so it has the effect of preventing pollution. Can be safely managed).

(2) Also, the present invention provides an apparatus for removing an organic halogen compound according to the above (1), comprising:
Dioxins are representative of at least one device selected from sand filtration device, membrane filtration device, adsorbent filling device, catalytic decomposition device, electrolysis device, ultraviolet irradiation device, microwave irradiation device, and ozone treatment device. The organic halogen compound to be removed can be efficiently removed, whereby the operation and effect of the above (1) can be further ensured.

(3) Further, according to the present invention, the powdered adsorbent is sprayed on the exhaust gas before being introduced into the wet washing tower or the exhaust gas in the wet washing tower to remove the organic halogen compound contained in the exhaust gas. Since it is configured to be adsorbed by the adsorbent and separated from exhaust gas, organic halogen compounds such as dioxin contained in exhaust gas can be effectively adsorbed and removed. The sprayed activated carbon powder is suspended as a slurry in the chemical solution to be circulated and sprayed. However, as described in the above (1) or (2), at least a part of the chemical solution to be circulated and sprayed is circulated to the dioxin removing device. The effect and effect of reducing the dioxin concentration in the chemical solution and not increasing the dioxin concentration in the exhaust gas can be obtained in the same manner as in the above (1) or (2).

(4) Further, according to the present invention, a powder adsorbent or a slurry adsorbent is mixed into a chemical solution sprayed in a wet-type washing tower, and an organic substance contained in exhaust gas in the process of spraying the adsorbent-mixed chemical solution. Since the halogen compound is adsorbed by the adsorbent and separated from the exhaust gas, dioxins in the exhaust gas can be adsorbed and removed as effectively as in (3) above in the process of spraying the chemical solution onto the exhaust gas. Further, the operation and effect described in the above (1) or (2) can be obtained equally.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of Embodiment 1 of the present invention.

FIG. 2 is an explanatory diagram of Embodiment 2 of the present invention.

FIG. 3 is an explanatory diagram of a third embodiment of the present invention.

FIG. 4 is an explanatory view showing an example of a conventional exhaust gas treatment method.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Wet washing tower (main body) 2 Chemical liquid spray part (chemical liquid tank) 3 Dehumidification part 4 Induction duct 5 Discharge duct 6 (Chemical liquid) circulation pump 7 Organic halogen compound removal device (dioxin removal device) 8 Activated carbon powder supply device 9 Activated carbon Slurry supply device 10 (fresh) chemical solution supply device A Flow control valve a, b Activated carbon powder supply line c, d Activated carbon slurry supply line

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B01D 53/77 C02F 1/32 4D037 C02F 1/52 1/44 F 4D050 // C02F 1/00 1/78 4D061 / 28 B01D 53/34 134E 1/30 ZAB 1/32 134B 1/44 125R 1/461 C02F 1/46 101C 1/78 F term (reference) 4D002 AA02 AA17 AA19 AA21 AB01 BA02 BA04 CA01 DA02 DA05 DA12 DA16 DA41 EA07 4D006 GA07 KA01 KB12 KC03 PA01 PB08 PB70 4D015 BA19 BB05 CA20 DA05 DA13 EA16 EA32 4D020 AA06 AA08 BA01 BB03 BC03 BC04 BC06 CB25 CC12 CD03 4D024 AA04 AB11 BA02 BB01 BC01 CA01 4D037A18 BC DB19 DC08 EA03 FA06

Claims (4)

[Claims] 1. A wet cleaning tower for spraying a chemical solution onto an exhaust gas containing an acidic component and an organic halogen compound such as dioxin to mainly remove the acidic component contained in the exhaust gas. A method for treating an exhaust gas and a chemical solution, wherein at least a part of the chemical solution to be circulated and sprayed is circulated through an organic halogen compound removing device to remove an organic halogen compound in the chemical solution, and then subjected to circulation spraying. 2. An organic halogen compound removing device includes a coagulating sedimentation device, a sand filtration device, a membrane filtration device, an adsorbent filling device, a catalytic decomposition device, an electrolysis device, an ultraviolet irradiation device, a microwave irradiation device, an ozone treatment device, The method for treating an exhaust gas and a chemical solution according to claim 1, wherein the method is at least one device selected from the group consisting of: 3. An exhaust gas before being introduced into the wet cleaning tower or an exhaust gas in the wet cleaning tower is sprayed with a powder adsorbent, and an organic halogen compound contained in the exhaust gas is adsorbed by the adsorbent and separated from the exhaust gas. The method for treating exhaust gas and a chemical solution according to claim 1 or 2, wherein 4. A powder adsorbent or a slurry adsorbent is mixed into a chemical solution sprayed in a wet washing tower, and an organic halogen compound contained in exhaust gas is adsorbed by the adsorbent in the process of spraying the adsorbent-mixed chemical solution. The method for treating an exhaust gas and a chemical solution according to claim 1 or 2, wherein the method is separated from the exhaust gas.