JP3812305B2 - Exhaust gas treatment equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an exhaust gas treatment apparatus that treats exhaust gas generated in the treatment of groundwater or soil containing volatile organic halogen compounds such as trichlorethylene and tetrachloroethylene.
[0002]
[Prior art]
In recent years, contamination of groundwater and soil by volatile organic halogen compounds harmful to the human body such as trichlorethylene and tetrachlorethylene has become a problem.
[0003]
By the way, since such a volatile organic halogen compound has low solubility in water and can be easily transferred to exhaust gas by stripping, a gas containing an organic halogen compound contained in groundwater or wastewater is taken out by aeration. Moreover, the gas containing the volatile organic halogen compound contained in the soil is taken out by depressurizing the extraction well. And after exhausting this exhaust gas with activated carbon and detoxifying it, it discharge | releases to air | atmosphere.
[0004]
However, even if the exhaust gas is adsorbed in this way, if the activated carbon after adsorption is regenerated, it is necessary to detoxify the components separated at that time, and harmful by-products are generated during incineration. There is a problem.
[0005]
Therefore, as a means for solving such a problem, a gas processing method disclosed in Japanese Patent Application Laid-Open No. 09-136017 is provided. In this method, the exhaust gas containing harmful components such as organic halogen compounds is irradiated with ultraviolet rays including a wavelength that generates ozone, and contact with a photocatalyst under ultraviolet irradiation to promote decomposition of organic halogen compounds such as trichlorethylene. is doing.
[0006]
[Problems to be solved by the invention]
By the way, in the said prior art, when organic halogen compound was low concentration, the contact efficiency was bad and the reaction time for a decomposition rate to fall was long, and there existed a problem that a decomposition processing tank became large.
[0007]
In addition, water droplets in the exhaust gas adhere to the treatment tank or catalyst support material, and chlorine or hydrogen chloride, which is a decomposition product of the organic halogen compound, dissolves into it and becomes a strong acid liquid, causing corrosion of the treatment tank or catalyst support material. It becomes.
[0008]
In addition, water droplets in the exhaust gas also adhere to the protective tube of the lamp and the catalyst surface and degrade the decomposition performance.
[0009]
SUMMARY OF THE INVENTION An object of the present invention is to provide an exhaust gas treatment apparatus that has high processing efficiency and can therefore be made compact in the decomposition treatment tank and can further improve the durability of the treatment tank.
[0012]
[ Means for Solving the Problems ]
According to a first aspect of the present invention, there is provided a water droplet separation part for separating water droplets in the exhaust gas with a louver, and an inlet for introducing the exhaust gas provided below the water droplet separation part. A first chamber having a photocatalyst carrying member configured to carry a photocatalyst on a chip or mesh-like sheet, and is partitioned near the ultraviolet lamp. The second chamber having an ultraviolet decomposition unit for decomposing the organic halogen compound in the exhaust gas having passed through the separation unit, and the second chamber and the second partition wall, and being decomposed by the ultraviolet decomposition unit A third chamber having an ozonolysis unit for decomposing ozone in the generated exhaust gas, and an exhaust port provided above the ozone decomposition unit for exhausting the exhaust gas that has passed through the ozone decomposition unit; Defined The first partition wall is provided with a first vent hole for introducing the exhaust gas that has passed through the water separation part into the second chamber, and the second partition wall is provided with a first vent hole at the bottom. A second vent hole for introducing the exhaust gas having passed through the second chamber into the third chamber, and a bottom portion including the second vent hole in the second chamber and the third chamber, PH adjustment for neutralizing the acidic product by passing the exhaust gas containing the acidic product and ozone generated by the decomposition process in the ultraviolet decomposition unit and before being introduced into the ozone decomposition unit through an alkaline liquid It is characterized by having a part.
[0013]
According to the exhaust gas treatment apparatus of the present invention, before the liquid of strong acid generated by chlorine or hydrogen chloride generated by ultraviolet decomposition and water droplets is generated, by separating the water droplets in the exhaust gas, Inhibits strong acid liquids. Therefore, there is no risk of strong acid liquids adhering to the treatment tank and the catalyst support material, they are not corroded, and they are stable without adhering to the lamp protection tube or catalyst surface. Thus, disassembly can be performed.
[0014]
Further, according to the exhaust gas treatment apparatus of the present invention, the water droplet separation unit, the ultraviolet decomposition unit, the pH adjustment unit, and the ozone decomposition unit are combined in one treatment tank, so that the apparatus can be made compact.
[0016]
According to the exhaust gas treatment apparatus of the present invention, the photocatalyst can be distributed at a high density, the exhaust gas can be brought into contact with the photocatalyst with high efficiency, and the decomposition treatment can be performed in a short time even when the concentration of the organic halogen compound is low. .
[0017]
The photocatalyst carrier preferably has a photocatalyst supported on a mesh sheet or chip made of a material capable of supporting a photocatalyst such as stainless steel or glass fiber. Examples of the photocatalyst include titanium oxide, tungsten oxide, and zinc oxide.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of an exhaust gas treatment method and apparatus according to the present invention will be described in detail with reference to the accompanying drawings.
[0019]
FIG. 1 shows a flow of an exhaust gas treatment method according to the present invention.
[0020]
In the exhaust gas treatment method according to the present invention, as shown in the flow of FIG. 1, groundwater and wastewater contaminated with an organic halogen compound are guided to the aeration tank 1, and the exhaust gas volatilized from the aeration tank 1 is removed by the water droplet separation unit 2. , The ultraviolet light decomposing unit 3, the pH adjusting unit 4, and the ozone decomposing unit 5 to be released to the atmosphere.
[0021]
The exhaust gas is subjected to removal of water droplets by the water droplet separation unit 2, irradiation of ultraviolet rays including a wavelength that generates ozone at the ultraviolet decomposition unit 3, and contact with a photocatalyst under ultraviolet irradiation to cause harmful components such as trichlorethylene. Disassembled. In that case, in the gas discharged | emitted from the ultraviolet decomposition part 3, decomposition products, such as hydrogen chloride, and the ozone produced | generated by ultraviolet irradiation are contained. This gas passes through the alkaline solution by the pH adjusting unit 4 and is neutralized, and the residual ozone is decomposed by the ozone decomposing unit 5.
[0022]
FIG. 2 conceptually shows an exhaust gas treatment apparatus according to the present invention.
[0023]
In this processing apparatus 10, the inside of the processing tank 11 is defined by a first partition wall 12 and a second partition wall 13 into a first chamber 14, a second chamber 15, and a third chamber 16. A vent hole 17 that communicates the first chamber 14 and the second chamber 15 is formed in the upper portion of the first partition wall 12, and the second chamber 15 and the third chamber 16 are formed in the lower portion of the second partition wall 13. Are formed. Further, an exhaust gas introduction port 19 for introducing the exhaust gas A from the outside into the processing tank 11 is formed in the lower portion of the side wall that defines the first chamber 14 of the processing tank 11, and the third chamber 16 of the processing tank 11 is opened. An exhaust gas discharge port 20 for exhausting exhaust gas from the inside of the treatment tank 11 to the outside is formed at the upper side of the defining side wall.
[0024]
A looper 21 is installed between the middle portion of the first chamber 14, that is, between the exhaust gas inlet 19 and the vent hole 17, and at the bottom of the first chamber 14, that is, below the exhaust gas inlet 19, A liquid reservoir 22 is formed.
[0025]
Further, an ultraviolet lamp 23 is disposed in the second chamber 15 along the flow of the exhaust gas, that is, in the vertical direction, and the photocatalyst carrier 24 is attached to the peripheral wall of the chamber 15 as shown in FIG. It is installed. As shown in FIG. 4, the photocatalyst carrier 24 is obtained by carrying a photocatalyst 24b on a mesh sheet 24a.
[0026]
In addition, an ozone decomposing material 25 is disposed in the middle portion of the third chamber 16, that is, between the vent hole 18 and the exhaust gas discharge port 20.
[0027]
Further, a pH adjusting liquid reservoir 26 for storing a pH adjusting liquid is formed at the bottom of the second chamber 15 and the bottom of the third chamber 16, that is, at the bottoms thereof that are communicated with each other by the vent hole 18. .
[0028]
In the exhaust gas treatment apparatus, titanium dioxide is used as the photocatalyst 24b, and the ultraviolet lamp 23 has a wavelength of about 380 nm or less. The pH adjusting liquid reservoir 26 contains an alkaline liquid, and the ozone decomposing material 25 is a platinum-based or manganese oxide-based ozone decomposing catalyst.
[0029]
In the exhaust gas treatment apparatus 10 configured as described above, exhaust gas containing harmful components such as trichlorethylene is introduced into the first chamber 14 from the exhaust gas inlet 19 of the treatment tank 11 by a pump or the like. The gas passes through the louver 21 and is sent from the vent hole 17 to the second chamber 15, and moisture in the gas is removed by the louver 21. The water trapped by the louver 21 is dropped into the liquid reservoir 22 as water droplets, and the liquid stored in the liquid reservoir 22 is discharged to the outside at an appropriate time.
[0030]
In the gas sent to the second chamber 15, components that are easily oxidized, organic halogen compounds, and the like in the gas are decomposed by ozone generated by the ultraviolet lamp 23 and the photocatalyst 24 b irradiated with infrared rays. At that time, chlorine, hydrogen chloride, ozone and the like are generated as decomposition products in the gas.
[0031]
Then, the gas is sent to the third chamber 16 through the vent hole 18 in the pH adjusting liquid reservoir 26, and chlorine or hydrogen chloride in the decomposition products is neutralized by the alkaline liquid in the pH adjusting liquid reservoir 26. The
[0032]
Further, the gas sent to the third chamber 16 is rendered harmless by the ozone decomposition material 25 and is discharged out of the treatment tank 11 from the exhaust gas discharge port 20.
[0033]
In the above embodiment, the photocatalyst carrier 24 is configured by supporting the photocatalyst 24b on the mesh-like sheet 24a. However, as shown in FIG. 5, the photocatalyst 24b may be supported on the chip 24c. . In this case, as shown in FIG. 6, the chip 24 c carrying the photocatalyst 24 b is filled in the net-like case 27 and the case 27 is mounted in the chamber 14.
[0034]
【The invention's effect】
As described above, in the exhaust gas treatment apparatus of the present invention, the treatment tank and the catalyst support material are not corroded by separating the water droplets in the exhaust gas before the by-product due to ultraviolet decomposition is generated. In addition, it can be stably decomposed without adhering to the protective tube and the contact surface of the lamp.
[0035]
In addition, by filling a sheet or chip carrying a photocatalyst in the vicinity of the ultraviolet lamp and bringing the ultraviolet ray and the photocatalyst into contact with each other with high efficiency, the decomposition treatment can be performed in a short time even when the concentration of the organic halogen compound is low.
[0036]
Moreover, since the water droplet separation unit, the ultraviolet decomposition unit, the pH adjustment unit, and the ozone decomposition unit have the same tank structure, a compact processing tank can be realized and space can be saved.
[Brief description of the drawings]
FIG. 1 is an exhaust gas treatment flowchart showing an exhaust gas treatment method according to the present invention. FIG. 2 is a cross-sectional perspective view conceptually showing an exhaust gas treatment apparatus according to the present invention. FIG. 4 is a conceptual partial cross-sectional perspective view showing an installed state of a photocatalyst carrier. FIG. 4 is an enlarged view showing a portion of the photocatalyst carrier shown in FIG. 3. FIG. 5 is a photocatalyst carrier in an exhaust gas treatment apparatus according to the present invention. FIG. 6 is an enlarged perspective view showing another embodiment of the present invention. FIG. 6 is a conceptual partial sectional perspective view showing the installation state of the photocatalyst carrier shown in FIG.
DESCRIPTION OF SYMBOLS 1 ... Aeration tank, 2 ... Water droplet separation part, 3 ... Ultraviolet decomposition part, 4 ... pH adjustment part, 5 ... Ozone decomposition part, 10 ... Exhaust gas processing apparatus, 11 ... Treatment tank, 12 ... 1st partition, 13 ... 1st 2 partition walls, 14 ... first chamber, 15 ... second chamber, 16 ... third chamber, 17 ... vent hole, 18 ... vent hole, 19 ... exhaust gas introduction port, 20 ... exhaust gas discharge port, 21 ... looper 22 ... Liquid reservoir, 23 ... UV lamp, 24 ... photocatalyst carrier, 24a ... sheet, 24b ... photocatalyst, 24c ... chip, 25 ... ozone decomposition material, 26 ... pH adjustment reservoir, 27 ... case, A ... exhaust gas

Claims (1)

A first chamber having a water droplet separation part for separating water droplets in the exhaust gas with a louver inside the treatment tank, and an introduction port provided below the water droplet separation part for introducing the exhaust gas;
A photocatalyst carrying member constituted by supporting the photocatalyst on a chip or a mesh-like sheet and being partitioned by the first chamber and the first partition wall is disposed in the vicinity of the ultraviolet lamp, and in the exhaust gas having passed through the water droplet separation unit A second chamber having an ultraviolet decomposition section for decomposing the organic halogen compound;
An ozone decomposing unit that is partitioned by the second chamber and the second partition and decomposes ozone in the exhaust gas generated by the decomposing process in the ultraviolet decomposition unit, and the ozone decomposing unit provided above the ozone decomposing unit And a third chamber having a discharge port for discharging the exhaust gas that has passed through the section,
A first vent for introducing the exhaust gas that has passed through the water droplet separator into the second chamber is provided on the upper part of the first partition,
A second ventilation hole for introducing the exhaust gas having passed through the second chamber into the third chamber is provided at a lower portion of the second partition wall,
The bottoms including the second vent holes in the second chamber and the third chamber have an acidic product and ozone generated by the decomposition process in the ultraviolet decomposition unit and before being introduced into the ozone decomposition unit. An exhaust gas treatment apparatus comprising a pH adjusting unit for passing an exhaust gas containing a neutral solution by passing the exhaust gas through an alkaline liquid.

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