JP2003290622A - Decomposition apparatus for gaseous organic compound - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a decomposition apparatus for a gaseous organic compound capable of efficiently decomposing a polluted gas containing the organic compound in a short time, easily treating an intermediate product generated by ultraviolet decomposition and reducing an equipment cost and a running cost. <P>SOLUTION: The decomposition apparatus for the gaseous organic compound is equipped with an ultraviolet decomposition unit 1 for irradiating the polluted gas containing the organic compound with ultraviolet rays with a wavelength of <300 nm to decompose the organic compound and an intermediate product treatment device 2 having an acidic electrolytic water supply pipe 9 and an alkali electrolytic water supply pipe 10 respectively connected thereto through a valve and selectively spraying strong alkali electrolytic water and strong acidic electrolytic water on the polluted gas containing the intermediate product formed by the decomposition of the organic compound to neutralize and decompose the intermediate product. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an apparatus for decomposing gaseous organic compounds.

[0002]

2. Description of the Related Art Organic compounds such as trichlorethylene and tetrachloroethylene have been used as cleaning agents and solvents for many years in the fields of semiconductors, metal oil cleaning, dry cleaning, etc. due to their excellent dissolving power. However, in recent years, it has been found that a carcinogenic substance exists in these chlorine-based organic compounds, and its harmfulness has been socially regarded as a problem, and emission control has been reached. Therefore,
At business sites that have used and discharged large amounts of these chlorine-based organic compounds in the past, soil and underground pollution on and around the site has become a serious problem. Further, if the pollutant gas contains a certain organic compound, the environment may be deteriorated by giving off a bad odor.

Usually, in order to purify the soil, the soil gas is sucked and the organic compounds contained therein are adsorbed and removed by activated carbon to be collected. For this reason, a large-scale adsorbing device using activated carbon is required at a place contaminated over a wide area with high concentration, which causes a problem of facility cost burden and running cost. Also, if it is attempted to adsorb and remove organic compounds contained in soil gas only with activated carbon, it is necessary to frequently replace the activated carbon, resulting in enormous labor and cost associated with replacement work, regeneration treatment, disposal, etc. of activated carbon. As a result, the burden on companies for soil purification has become extremely large.

By the way, a technique of irradiating ultraviolet rays to decompose organic compounds is conventionally known. For example, in the case of cleaning the surface of a semiconductor wafer, a high-energy ultraviolet ray (wavelength 172 nm) is irradiated by an excimer lamp or the like to irradiate the organic surface. Decomposing the compound. When irradiated with such high-energy ultraviolet rays, organic compounds are decomposed in an extremely short time. However, since the excimer lamp is extremely expensive, the equipment cost is enormous, and the power consumption is extremely large, it is not practical to use it for cleaning the soil gas.

When an inexpensive low-pressure mercury lamp, medium-pressure mercury lamp, or high-pressure mercury lamp is used to irradiate ultraviolet rays to decompose organic compounds, hydrogen chloride, haloacetic acid, or other reactive substances are unstable as intermediate products. Occurs, and it takes a very long time to decompose this into a stable substance. Therefore, a gas containing an organochlorine compound is irradiated with ultraviolet rays including ultraviolet rays having a wavelength of 300 nm or less to decompose a reaction intermediate having a chlorine atom, and further, a microbial treatment is performed to decompose the reaction intermediate. The disassembling method is JP-A-8-
It is disclosed in Japanese Patent No. 24335. However, microbial treatment is excellent in that it is environmentally friendly, but it is difficult to manage and the decomposition rate is very slow, so it takes time to treat,
In particular, there is a problem that high-concentration pollution cannot be dealt with.

[0006]

SUMMARY OF THE INVENTION The present invention is capable of efficiently decomposing pollutant gases containing organic compounds in a short time, facilitating the treatment of intermediate products generated by ultraviolet decomposition, and reducing equipment costs and running. An object of the present invention is to provide a decomposing device for a gaseous organic compound that can be manufactured at low cost.

[0007]

An apparatus for decomposing a gaseous organic compound according to the present invention comprises an ultraviolet decomposing unit for decomposing the organic compound by irradiating a pollutant gas containing the organic compound with ultraviolet rays having a wavelength of less than 300 nm. An acidic electrolyzed water supply pipe and an alkaline electrolyzed water supply pipe are connected via valves, respectively, and a strong alkaline electrolyzed water and a strongly acidic electrolyzed water are selectively sprayed onto an intermediate product produced by decomposing the organic compound. And an intermediate product treatment device for neutralizing and decomposing the intermediate product. It is considered that the chemical bond of the organic compound contained in the polluted gas is broken by the ultraviolet irradiation, and a plurality of intermediate products produced as a result of the decomposition of the organic compound are mixed in an unstable radical state by the ultraviolet irradiation. These unstable gaseous intermediate products are contacted by spraying strongly acidic electrolyzed water or strongly alkaline electrolyzed water,
It can be converted into a more stable and harmless substance by being gas-washed, neutralized, or decomposed. In addition, the strong alkaline electrolyzed water and the strongly acidic electrolyzed water sprayed on the polluted gas are harmless to the human body, and there is no concern that the waste water pollutes the environment.

Even if the intermediate product treatment device is connected to the intermediate part of the ultraviolet decomposing unit and the pollutant gas in the ultraviolet decomposing unit is selectively sprayed with strong alkaline electrolyzed water and strong acidic electrolyzed water, the intermediate product The treatment device may be connected to the downstream of the ultraviolet decomposing unit, and strong alkaline electrolyzed water and strong acidic electrolyzed water may be selectively sprayed on the polluted gas passing through the ultraviolet decomposing unit. When the intermediate product treatment device is connected to the downstream of the ultraviolet decomposition unit, strong alkaline electrolyzed water and / or strong acidic electrolyzed water may be sprayed on the polluted gas in the ultraviolet decomposition unit. With this configuration, decomposition of the organic compound by ultraviolet rays is promoted, and the processing time is shortened.
The strong alkaline electrolyzed water and the strongly acidic electrolyzed water sprayed on the ultraviolet decomposition unit are produced at the same time as the strongly alkaline electrolyzed water and the strongly acidic electrolyzed water sprayed in the intermediate product treating apparatus, so that the cost increase can be suppressed.

The ultraviolet decomposition unit comprises a decomposition cell having an ultraviolet irradiation lamp installed therein, and a gas inlet may be formed in the peripheral wall of the decomposition cell so as to blow a pollutant gas along the diameter of the decomposition cell. . This makes it difficult for the polluted gas to move along the inner surface of the decomposition cell, prolongs the residence time of the polluted gas in the decomposition cell, enhances the irradiation intensity of ultraviolet rays, and improves the decomposition efficiency. As the ultraviolet irradiation lamp, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an amalgam lamp, a halogen lamp, an excimer lamp or the like can be used.

In this case, it is preferable that the plurality of ultraviolet irradiation lamps be hung on the upper surface of the decomposition cell at equal intervals so that the contaminated gas is uniformly irradiated with ultraviolet rays. Since the ultraviolet intensity is inversely proportional to the irradiation distance, the distance between the ultraviolet irradiation lamps is 100 mm or less, preferably 20 mm or less. Further, in order to prevent the attenuation of ultraviolet rays having a relatively short wavelength, the protective tube of the ultraviolet irradiation lamp has a wavelength of 172 nm or more.
It is desirable to use a synthetic quartz glass that transmits 0% or more as a material. It is preferable to use an ultraviolet lamp that is as thin as possible, and use a thin tube having a protective cylinder with a diameter of about 6 mm to 20 mm.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below in detail with reference to the drawings. The decomposing device for a gaseous organic compound is connected to a gas suction device for sucking a contaminated gas containing an organic compound from contaminated soil, and as shown in FIG. 1, an ultraviolet decomposing unit 1 into which the contaminated gas is introduced, and an ultraviolet decomposing unit. 1, an intermediate product treatment device composed of a scrubber 2 connected downstream, an activated carbon adsorption unit 3 connected downstream of the scrubber 2, and an electrolyzed water generation device 4.

The electrolyzed water generator 4 uses an Olyxer Medica CL (trade name, manufactured by Miura Denshi Co., Ltd.) and contains a water-soluble electrolyte such as sodium chloride, potassium chloride or magnesium chloride. When water is electrolyzed, strongly acidic electrolyzed water is taken out from the anode side and strong alkaline electrolyzed water is taken out from the cathode side. The strongly acidic electrolyzed water and the strongly alkaline electrolyzed water thus obtained are
Since it is harmless to the human body, there is no risk of polluting the environment even if it contacts functional gas as functional water.

The ultraviolet decomposing unit 1 is constructed by connecting two decomposing cells 6 in series in which a plurality of ultraviolet irradiation lamps composed of a low pressure mercury lamp 5 (FIGS. 2 and 3) are installed inside a stainless steel pipe. . The low-pressure mercury lamp 5 uses a synthetic quartz glass that transmits 80% or more of ultraviolet rays having a wavelength of 172 nm or more as a protective tube and consumes 13 W of power.
Then, an ultraviolet ray having a wavelength of 254 nm and an ultraviolet ray of 185 nm are irradiated. Further, as shown in FIG. 2, the low-pressure mercury lamp 5 is suspended from the upper surface of the decomposition cell 6, one lamp is arranged at the center of the upper surface of the decomposition cell 6, and the rest are arranged at equal intervals on the peripheral portion of the upper surface. .

As shown in FIG. 3, the polluted gas is introduced from the gas inlet 7 formed at one end of the diameter in the upper part of the peripheral wall of one of the decomposition cells 6 and the upper part of the peripheral wall of the other decomposition cell 6 has the same diameter. It is taken out from a gas outlet 8 formed at one end. Then, the anode side of the electrolyzed water generator 4 and each decomposition cell 6 of the ultraviolet decomposition unit 1 are connected by an acidic electrolyzed water supply pipe 9, and the decomposition cell 6 and the acidic electrolyzed water supply pipe 9 are connected.
When you open the valve installed at the connection with, the disassembly cell 6
Strongly acidic electrolyzed water is sprayed inside. Furthermore, the cathode side of the electrolyzed water generator 4 and the ultraviolet decomposition unit 1
Each of the decomposition cells 6 is connected by an alkaline electrolyzed water supply pipe 10, and when a valve installed at a connection portion between the decomposition cell 6 and the alkaline electrolyzed water supply pipe 10 is opened, strong alkaline electrolyzed water is generated in the decomposition cell 6. It is supposed to be sprayed.

Both ends of a circulation pipe 11 having a pump 12 are connected to the upper and lower parts of the scrubber 2, and the gas that has passed through the ultraviolet decomposition unit 1 and flowed into the lower part of the scrubber 2 is
The pump 12 pushes up the inside of the circulation pipe 11, returns it to the upper part of the scrubber 2, and circulates in the scrubber 2. A pH measuring device 25 is provided in the scrubber 2, and the pH of the pollutant gas flowing into the scrubber 2 can be measured by the pH measuring device 25. Further, the circulation pipe 11 is connected to the acidic electrolyzed water supply pipe 9 and the alkaline electrolyzed water supply pipe 10 via valves, respectively, and the valves are opened according to the pH of the pollutant gas measured by the pH measuring device 25. The strongly acidic electrolyzed water and the strongly alkaline electrolyzed water are selectively sprayed onto the gas circulating in the scrubber 2 to neutralize and decompose the intermediate products contained in the gas.

A drainage neutralization tank 14 is installed in the drainage channel 13 extending from the scrubber 2, and an acidic electrolyzed water supply pipe 9 and an alkaline electrolyzed water supply pipe 10 are provided in the drainage neutralization tank 14 via valves. Strong alkaline electrolyzed water or strongly acidic electrolyzed water is added to the wastewater connected and stored in the wastewater neutralization tank 14 to neutralize it, and then the wastewater is discharged. The activated carbon adsorption unit 3 has a built-in activated carbon filter, and the minute residual compounds contained in the gas passing through the scrubber 2 are adsorbed and removed here. Further, an exhaust pipe 16 having a pump 15 is connected to the activated carbon adsorption unit 3 so that the clean gas that has passed through the activated carbon filter is exhausted.

The apparatus for decomposing gaseous organic compounds is used as follows. Contaminant gas containing organic compounds sucked from the soil is passed through the gas inlet 7 to the ultraviolet decomposition unit 1
Of the strong acidic electrolyzed water or the strong alkaline electrolyzed water produced by the electrolyzed water producing apparatus 4, or both of them are sprayed into the electrolysis cell 6 to be brought into contact with the polluted gas. The low pressure mercury lamp 5 is turned on to irradiate the polluted gas with ultraviolet rays. Then, the organic compounds contained in the polluted gas are decomposed by the ultraviolet irradiation, and strong acidic electrolyzed water and / or
Alternatively, the strong alkaline electrolyzed water accelerates the decomposition reaction.

The pollutant gas taken out from the gas outlet 8 after passing through the ultraviolet decomposing unit 1 contains an intermediate product generated as a result of the decomposition of the organic compound, and the pollutant gas containing this intermediate product. Flows into the scrubber 2. The pH of the pollutant gas flowing into the scrubber 2 is measured by the pH measuring device 25, and the polluted gas circulates in the scrubber 2 for a certain period of time through the circulation pipe 11. Then, when passing through the circulation pipe 11, p measured by the pH measuring device 25
Depending on H, the pollutant gas is sprayed with strongly acidic electrolyzed water or strongly alkaline electrolyzed water to neutralize the intermediate product contained in the pollutant gas.

Depending on the organic compound contained in the polluted gas, the polluted gas containing the intermediate product may be neutral. In this case, strong acidic electrolyzed water and strong alkaline electrolyzed water are simultaneously sprayed to form an intermediate product. Decomposes the product. Further, even a small amount of the organic compound remaining after passing through the ultraviolet decomposing unit 1 is further decomposed by spraying strongly acidic electrolyzed water or strongly alkaline electrolyzed water. A part of the intermediate product which is not decomposed or a part of the by-product generated by the neutralization is dissolved in the sprayed electrolyzed water, and the drainage channel 13
Is discharged to.

Since the water discharged from the scrubber 2 to the drainage channel 13 is often acidic or alkaline, strong alkaline electrolyzed water or strongly acidic electrolyzed water is added in the wastewater neutralization tank 14 for neutralization. Then, it is discharged to the outside. The gas that circulates in the scrubber 2 for an integrated time flows into the activated carbon adsorption unit 3, adsorbs and removes the slightly remaining intermediate products and organic compounds by the activated carbon filter, and then is exhausted to the outside.

The ultraviolet decomposition unit 1 may be used as an intermediate product processing device. In this case, each electrolysis cell 6 is provided with a pH measuring device 25, and the pH measuring device 25
Contaminant gas in the UV decomposition unit 1 is selected by spraying strongly acidic electrolyzed water and strongly alkaline electrolyzed water from the connected acidic electrolyzed water supply pipe 9 and alkaline electrolyzed water supply pipe 10 according to the pH measured in The intermediate product contained in is neutralized and decomposed. Then, the strongly acidic electrolyzed water or the strongly alkaline electrolyzed water sprayed for neutralization also decomposes the organic compound contained in the polluted gas. At this time, the scrubber 2 may or may not be installed downstream of the ultraviolet decomposition unit 1. Further, without connecting the acidic electrolyzed water supply pipe 9 and the alkaline electrolyzed water supply pipe 10 to the ultraviolet decomposition unit 1, the organic compounds contained in the polluted gas in the ultraviolet decomposition unit 1 are decomposed only by the ultraviolet rays, and then the scrubber 2 Strong alkaline electrolyzed water and strongly acidic electrolyzed water may be selectively sprayed therein.

(Example) In the apparatus for decomposing gaseous organic compounds shown in FIG. 1, the decomposition cell 6 had a diameter of 200 mm and a length of 600 mm, and seven low-pressure mercury lamps 5 were set. Then, a pollutant gas containing trichlorethylene (hereinafter referred to as TCE) is introduced into the ultraviolet decomposition unit 1, and a strong acidic electrolyzed water having a pH of 2.1 to 2.4 is added at a rate of 1 per minute.
00 ml was sprayed. In addition, the scrubber 2 has a pH of 11.
0 liters of strong alkaline electrolyzed water is sprayed every minute at a flow rate of 12.5
A pollutant gas was circulated at a flow rate of 1 / min.

In the test 1, the pollutant gas having a TCE concentration of 50 ppm and the air flow rate of 400 l / min were used for the ultraviolet decomposition unit 1.
Before the UV decomposition unit 1, between the UV decomposition unit 1 and the scrubber 2, between the scrubber 2 and the activated carbon adsorption unit 3 and at four points after the activated carbon adsorption unit 3 after 10 minutes and After 30 minutes, TCE concentration, hydrogen chloride concentration, phosgene concentration, chlorine concentration, and ozone concentration were measured, and the results are shown in FIG. In addition, the pH of the scrubber 2 is tested at the beginning of the test, 10 minutes later,
The result of measurement after 30 minutes is shown in FIG.

In Test 2, the TCE concentration was 100.
A ppm polluted gas was blown into the gas inlet 7 at an air flow rate of 400 l / min, and in the same manner as in Test 1, at 4 points of ,,, after 10 minutes and 30 minutes, TCE concentration, hydrogen chloride concentration, phosgene The concentration, chlorine concentration, and ozone concentration were measured, and the pH in the scrubber 2 was measured at the start of the test, 10 minutes later, and 30 minutes later, and the results are shown in FIGS. 6 and 7, respectively. From the results of Test 1 and Test 2, it was found that the TCE contained in the polluted gas was almost decomposed by the irradiation of ultraviolet rays, and the remaining organic compounds were decomposed to a very low concentration while circulating through the scrubber 2. In addition, most of the intermediate product generated as a result of decomposing the organic compound by ultraviolet irradiation is neutralized in the scrubber 2,
It was found that the extremely small organic compounds and intermediate products contained in the gas passing through were completely adsorbed and removed by the activated carbon adsorption unit 3.

Further, in Tests 3 to 9, using the UV decomposition unit 1, 7 of the organic compounds, which are 7 major malodorous substances, such as hydrogen sulfide, acetaldehyde, pyridine, ammonia, trimethylamine, acetic acid, and methyl mercaptan are used. Regarding the type, a pollutant gas with a concentration of 10 ppm was blown into the gas inlet 7 at an air flow rate of 400 l / min, and as in Test 1, the organic compound concentration was measured at four points ,,, and intermediate generation was performed at three points. The substance concentration was measured. In Test 3, a decomposition test was conducted on a pollutant gas containing hydrogen sulfide (H ₂ S), strong alkaline electrolyzed water was sprayed onto the scrubber 2, and immediately after the test was started, 10 minutes, 30 minutes, and 50 minutes later.
Density measurements were taken after minutes and 90 minutes. FIG. 8 shows a change with time of the H ₂ S concentration, and FIG. 9 shows S produced as an intermediate product.
The changes over time of the O ₂ concentration and the ozone concentration are shown.

In Test 4, acetaldehyde (CH ₃ C
OH) -containing polluted gas was flowed, and strongly acidic electrolyzed water was sprayed onto the scrubber 2, and the concentration was measured immediately after the start of the test, 10 minutes, 30 minutes, and 50 minutes later. FIG. 10 shows acetaldehyde concentration, and FIG. 11 shows acetic acid (CH3COOH) concentration and ozone concentration expected as intermediate products. In addition,
Although acetic acid was expected as an intermediate product, as can be seen from FIG. 11, the contaminated gas after passing through the ultraviolet decomposing unit 1 contains practically no acetic acid, so it is not necessary to consider the neutralization decomposition of acetic acid. It seems that there is no.

In Test 5, a pollutant gas containing pyridine (C ₅ H ₅ N) was blown into the gas inlet 7, and the strongly acidic electrolyzed water was sprayed onto the scrubber 2. Immediately after the start of the test, 10 minutes later, 30 minutes later, and 50 minutes later. After a minute, the concentration was measured. FIG. 12 shows the pyridine concentration, and FIG. 13 shows the NOx concentration and ozone concentration expected as intermediate products. In test 6, ammonia (N
A pollutant gas containing H ₃ ) was introduced into the gas inlet 7, the strongly acidic electrolyzed water was sprayed onto the scrubber 2, and the concentration was measured immediately after the start of the test, 10 minutes, 30 minutes, and 50 minutes later. 14
15 shows the ammonia concentration, and FIG. 15 shows the NOx concentration and ozone concentration expected as intermediate products.

In test 7, trimethylamine ((C
H _{3) 3} N) flowing a contaminated gas containing, by spraying a strongly acidic electrolyzed water to the scrubber 2, immediately after the start of the test, after 10 minutes, 30
The concentration was measured after 50 minutes and after 50 minutes. FIG. 16 shows the trimethylamine concentration, and FIG. 17 shows the NOx concentration and ozone concentration expected as intermediate products. Although ammonia is expected as an intermediate product, it was difficult to distinguish it from trimethylamine, and the concentration could not be measured. In addition, in Tests 5 to 7, N was used as an intermediate product.
Although Ox was predicted, since the polluted gas after passing through the ultraviolet decomposing unit 1 contains almost no NOx, its neutralization decomposition may not be considered.

In Test 8, a pollutant gas containing acetic acid (CH ₃ COOH) was introduced into the gas inlet 7, and strong alkaline electrolyzed water was sprayed onto the scrubber 2. Immediately after the start of the test, 10 minutes later, 3
The concentration was measured after 0 minutes and 50 minutes. FIG. 18 shows the acetic acid concentration, and FIG. 19 shows the ozone concentration generated as an intermediate product. In Test 9, methyl mercaptan (CH ₃ S
Immediately after starting the test, a pollutant gas containing H) was introduced into the gas inlet 7, and the scrubber 2 was sprayed with strong alkaline electrolyzed water.
The concentration was measured after 30 minutes and 50 minutes. Figure 2
The methyl mercaptan concentration is shown in 0, and the SO ₂ concentration, H ₂ S concentration, and ozone concentration expected as intermediate products are shown in FIG. Even in this test, H ₂ S expected as an intermediate product was not detected in the gas after passing through the ultraviolet unit 1. From the results of tests 3 to 9, it was found that almost all malodorous substances can be decomposed by the decomposition device of the present invention.

In Test 10, in order to investigate the effect of ultraviolet rays on the decomposition of organic compounds, as shown in FIG. 22, a gas mixing tank 17 was used.
A test cell 19 having a volume of 180 l in which ten ultraviolet lamps 18 are suspended from the upper surface is installed downstream of the VOC monitor 2 and the VOC monitor 2 is provided on the upstream side and the downstream side of the test cell 19, respectively.
0 is installed, and a pollutant gas having a TCE concentration of 50 ppm is added to this device at 100 l / min and 200 l / min.
It was continuously supplied at min, 300 l / min, and 400 l / min. Then, in the pattern 1 in which 10 ultraviolet lamps 18 are turned on, the pattern in which 7 ultraviolet lamps are turned on 2, the pattern in which 6 ultraviolet lamps are turned on 3, the pattern 3 in which three ultraviolet lamps are turned on, and the pattern 5 in which one ultraviolet lamp 18 is turned on 23 shows the result of measuring the TCE concentration on the downstream side. Further, the TCE decomposition rate is (1-downstream concentration / upstream concentration) × 10
It is calculated by the formula of 0% and is shown in FIG.

In Test 11, an experiment was conducted in the same manner as in Test 10 except that tetrachloroethylene (PCE) was used instead of TCE, and the PCE concentration was measured.
26 shows the PCE decomposition rate, respectively. Test 12
Was tested in the same manner as in Test 10 except that cis-1,2-dichloroethylene (cis-1,2-DCE) was used instead of TCE, and the cis-1,2-DCE concentration was measured. FIG. 27 shows the cis-1,2-DCE decomposition rate, and FIG. 28 shows them.

In Test 13, an experiment was conducted in the same manner as in Test 10 except that monochloroethylene was used instead of TCE, and the results of measuring the monochloroethylene concentration are shown in FIG. 29 and the monochloroethylene decomposition rate is shown in FIG. Shown respectively. Test 14 was conducted in the same manner as in Test 10 except that ethyl acetate was used instead of TCE, and the results of measuring the ethyl acetate concentration are shown in FIG. 31 and the ethyl acetate decomposition rate is shown in FIG.
2 respectively. In Test 15, a gas having a toluene concentration of 50 ppm was used in place of TCE instead of TCE.
FIG. 33 shows the results of measuring the toluene concentration by supplying 100 l / min to the same test apparatus as in No. 0. From the results of Tests 10 to 15, the smaller the test flow rate, the higher the night-time UV decomposition rate, and the more chlorine-containing tetrachloroethylene is easily decomposed by UV rays, and ethyl acetate and toluene without chlorine are less likely to be decomposed by UV rays. I understood it.

Test 16 was carried out in order to investigate the effect of promoting decomposition when the strongly alkaline electrolyzed water, the strongly acidic electrolyzed water, and the mixed water thereof were sprayed and irradiated with ultraviolet rays. In test 16, FIG.
As shown in, an ultraviolet lamp 18 for irradiating an ultraviolet ray having a wavelength of 254 nm with an output of 30 W is provided with an inner diameter of 120 mm and a height of 130.
It was installed in a 0 mm test cell 19 and a gas in which TCE gas and dilution air were mixed was introduced into the test cell 19 at a flow rate of 3 l / min. Further, using the atomizer 21, either strongly acidic electrolyzed water, strongly alkaline electrolyzed water, mixed water in which strongly acidic electrolyzed water and strong alkaline electrolyzed water were mixed at a ratio of 1: 1, or tap water was placed in the test cell 19 in an amount of 10 l. After the TCE concentration was stabilized by spraying at / min, the UV lamp 18 was repeatedly turned on and off, and the TCE concentration of the gas sampled from the sampling port 22 formed downstream of the test cell was measured at 10-minute intervals. The results and the TCE decomposition rate are shown in FIG. From the results of Test 16, it was found that spraying strongly acidic electrolyzed water, strongly alkaline electrolyzed water, or a mixed water of strongly acidic electrolyzed water and strongly alkaline electrolyzed water clearly increased the decomposition efficiency as compared with the case of spraying tap water. It was

In Test 17, a test apparatus as shown in FIGS. 36 and 37 is used. The test apparatus has a test cell 19 with a replaceable ultraviolet lamp 18 suspended on the top surface. In the lower part of the peripheral wall of the test cell 19, a first gas inlet 7a for introducing gas along the diameter is formed, and
A second gas inlet 7b for introducing the gas is formed along the tangent line, and a first gas outlet 8a for taking out the gas along the diameter is formed on the upper part of the peripheral wall of the test cell 19, and along the tangent line. A second gas outlet 8b for taking out gas is formed.

Then, an ultraviolet lamp 18 with an output of 13 W for irradiating an ultraviolet ray having a wavelength of 185 nm and an ultraviolet ray of a wavelength of 254 nm with a protective tube, or an output lamp 40 W for emitting an ultraviolet ray of a wavelength of 185 nm and an ultraviolet ray of a wavelength of 254 nm without a protective tube.
Using the ultraviolet lamp 18 of No. 3, a gas having a TCE concentration of 50 ppm is supplied at a flow rate of 100 l / min, 200 l / min, 30
The first gas inlet 7 at 0 l / min and 400 l / min
a through the flow path from a to the first gas outlet 8a and through the flow path from the second gas inlet 7b to the second gas outlet 8b, the upstream side and the downstream side of the test cell 19 Was measured to determine the TCE decomposition rate. The result is shown in FIG.

From the results of Test 17, it was found that when the pollutant gas was introduced into the cell along its diameter toward the center of the cross section, the decomposition efficiency was higher than that when it was introduced along the tangential direction. This is considered to be because when the gas is introduced in the tangential direction of the cell, the gas flows along the wall surface of the cell, so that the ultraviolet irradiation intensity is weakened and the residence time in the cell is shortened.

FIG. 39 shows a test apparatus used in tests 18 to 20. This test equipment uses an ultraviolet lamp 18
Internal diameter 45 mm, length 500 mm, volume 800 ml
Tedlar bag 2 containing test gas in test cell 19 of
3 was connected, and gas was sucked into the test cell 19 by the pump 24 until the gas had a constant concentration. Then, the ultraviolet lamp 18 was turned on for 20 minutes, and the change in gas concentration was observed by the VOC sensor 20. UV lamp 18 has a wavelength of 1
Toshiba GLS6UN that emits 85 nm UV light and 254 nm UV light, Toshiba GLS6UJ that emits 254 nm UV light, and black light (Miyata Elevum) that emits UV light having a wavelength of 300 nm or more, and the initial gas concentration is 10 ppm. And the case of 100 ppm were tested.

In Test 18, trichlorethylene was used as the test gas, the TCE concentration when the initial gas concentration was 10 ppm was shown in (a) of FIG. 40, and the TCE concentration when it was 100 ppm was shown in (b) of FIG. Show. Test 19
The PCE concentration when tetrachloroethylene was used as the test and the initial gas concentration was set to 10 ppm was shown in Fig. 41 (a).
41B shows the PCE concentration at 100 ppm. In test 20, cis- was used as a test gas.
Using 1,2-dichloroethylene, the initial gas concentration was 1
The cis-1,2-DCE concentration when 0 ppm is shown in FIG.
In (2) of 2 above, cis-1,2 at 100 ppm
-DCE concentration is shown in (b) of FIG. 42. From the results of Test 18 to Test 20, if the wavelength of the ultraviolet ray is 300 nm or more, the concentration change is almost the same as the blank measurement value,
It was found that organic compounds were not decomposed.

In Test 21, the possibility of the ultraviolet decomposing effect of Yperit (ClCH ₂ CH ₂ ) ₂ S, which is a poison gas for chemical weapons, was verified. Ultraviolet with wavelength 185nm and wavelength 2
An ultraviolet lamp for irradiating an ultraviolet ray of 54 nm was installed in 500 ml of durumbin, and chloromethyl methyl sulfide (ClCH ₂ SCH ₃ , hereinafter, as an iperit mimetic agent)
A Tedlar bag accommodating CMMS) was connected to this duran bin, and the air in the duran bin was replaced with CMMS by suctioning with a separately connected pump. afterwards,
The UV lamp was turned on to measure the CMMS concentration, and the result is shown in FIG. From Test 21, it was found that although the decomposition rate was not so high, the mimetic agent of Iperit could be decomposed to about half by irradiation with ultraviolet rays.

[0040]

According to the inventions of claims 1 to 3, the harmful organic compounds contained in the polluted gas are decomposed by ultraviolet rays of relatively high energy having a wavelength of less than 300 nm, resulting in an unstable intermediate product. Since the product is neutralized with strong alkaline electrolyzed water and strong acid electrolyzed water and decomposed, the treatment time is short and a large-scale device is not required. Further, even organic compounds that cannot be completely decomposed by UV irradiation can be decomposed to a lower level by spraying strong alkaline electrolyzed water or strongly acidic electrolyzed water. Furthermore, since strong alkaline electrolyzed water and strongly acidic electrolyzed water are harmless to the human body, there is no risk of polluting the environment.

According to the invention of claim 4, the decomposition of the organic compound in the ultraviolet decomposition unit is promoted, and the processing time can be further shortened. According to the invention of claim 5, the pollutant gas stays in the decomposition cell for a longer period of time and the irradiation intensity of the ultraviolet rays to the pollutant gas becomes stronger, so that the decomposition efficiency is further improved. According to the invention of claim 6, the pollutant gas is uniformly irradiated with ultraviolet rays with high intensity, so that the organic compound decomposition efficiency is good. Claim 7
According to the invention, the ultraviolet rays having a short wavelength are irradiated to the polluted gas without being blocked by the protective cylinder, so that the organic compound can be decomposed in a short time.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a device for decomposing a gaseous organic compound showing an embodiment of the present invention.

FIG. 2 is a side sectional view of an exploded cell.

FIG. 3 is a plan sectional view of the disassembly cell.

FIG. 4 is a diagram showing a result of measuring a contamination concentration in Test 1.

FIG. 5 is a diagram showing pH measurement results in Test 1.

FIG. 6 is a diagram showing a result of measuring a contamination concentration in Test 2.

FIG. 7 is a diagram showing pH measurement results in Test 2.

FIG. 8 is a diagram showing changes over time in organic compound concentration in Test 3.

FIG. 9 is a view showing a change with time of an intermediate product concentration in Test 3.

FIG. 10 is a diagram showing changes over time in organic compound concentration in Test 4.

FIG. 11 is a view showing a time-dependent change in the concentration of the intermediate product compound in Test 4.

FIG. 12 is a diagram showing changes in organic compound concentration over time in Test 5.

FIG. 13 is a view showing a change with time of an intermediate product concentration in Test 5.

FIG. 14 is a diagram showing changes over time in organic compound concentration in Test 6.

FIG. 15 is a view showing a change with time of an organic compound concentration in Test 6.

FIG. 16 is a view showing a time-dependent change in organic compound concentration in Test 7.

FIG. 17 is a diagram showing a time-dependent change in the concentration of intermediate products in Test 7.

FIG. 18 is a view showing a time-dependent change in organic compound concentration in Test 8.

FIG. 19 is a diagram showing a time-dependent change in the concentration of intermediate products in Test 8.

FIG. 20 is a diagram showing changes over time in organic compound concentration in Test 9.

FIG. 21 is a view showing a change over time in the concentration of intermediate products in Test 9.

FIG. 22 is a schematic diagram of a test apparatus used in tests 10 to 15.

FIG. 23 is a diagram showing measurement results of TCE concentration in Test 10.

FIG. 24 is a diagram showing calculation results of TCE decomposition rate in Test 10.

FIG. 25 is a view showing a measurement result of PCE concentration in test 11.

FIG. 26 is a diagram showing calculation results of PCE decomposition rate in Test 11.

FIG. 27 shows the measurement results of cis-1,2-DCE concentration in Test 12.

FIG. 28 is a diagram showing calculation results of cis-1,2-DCE decomposition rate in Test 12.

FIG. 29 is a view showing the measurement results of monochlorobenzene concentration in Test 13.

FIG. 30 is a diagram showing a calculation result of a decomposition rate of monochlorobenzene in Test 13.

FIG. 31 shows the measurement results of ethyl acetate concentration in Test 14.

FIG. 32 is a view showing a calculation result of an ethyl acetate decomposition rate in Test 14.

FIG. 33 shows the measurement results of toluene concentration in Test 15.

FIG. 34 is a schematic diagram of a test apparatus used for test 16.

FIG. 35 is a graph showing TCE concentration and TCE decomposition rate measured in Test 16.

FIG. 36 is a side sectional view of a test cell used in test 17.

FIG. 37 is a plan sectional view of a test cell used in test 17.

FIG. 38 is a view showing a TCE decomposition rate in Test 17.

FIG. 39 is a schematic view of an apparatus used in tests 18 to 20.

FIG. 40 is a diagram showing a time-dependent change in TCE concentration in test 18.

FIG. 41 is a view showing a change over time in PCE concentration in Test 19.

FIG. 42 is a view showing a time-dependent change in cis-1,2-DCE concentration in Test 20.

FIG. 43 is a view showing a change in CMMS concentration in Test 21.

[Explanation of symbols]

1 UV decomposition unit 2 scrubber 3 Activated carbon adsorption unit 4 Electrolyzed water generator 5 Low-pressure mercury lamp 6 Disassembly cell 7 gas inlet 8 gas outlets 9 Acidic electrolyzed water supply pipe 10 Alkaline electrolyzed water supply pipe 11 Circulation pipe 12 pumps 13 drainage channels 14 Drainage neutralization tank 15 fans 16 Exhaust pipe 17 Mixture tank 18 UV lamp 19 test cell 20 VOC sensor 21 Atomizer 22 Collection port 23 Tedlar bag 24 pumps 25 pH measuring device

Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C07B 37/06 G21K 5/00 W G21K 5/00 Z 5/10 F 5/10 B01D 53/34 117Z (72) Invention Person Takahiro Terashima 7th Yonbancho, Chiyoda-ku, Tokyo In-house (72) Inventor Yoshiko Nakato 7th Yonbancho, Chiyoda-ku, Tokyo In-house (72) Inventor Kozo Nitta Chiyoda-ku, Tokyo 7th Yonbancho Koken Stock Association In-house (72) Inventor Shinji Noguchi 7th Yonbancho Chiyoda-ku, Tokyo Koken Stock Association In-house F-term (reference) 4D002 AA01 AA03 AA13 AA14 AA21 AA32 AA40 AC10 BA02 BA09 CA01 CA07 DA35 DA41 EA02 4D020 AA04 AA08 BA30 BB03 CB08 CB25 CD10 4G075 AA03 AA37 BA05 BA06 BB04 BD13 CA33 CA51 DA02 DA18 EB01 EB09 EB32 EC01 FB06 4H006 AA05 AC13 AC26 BA95 BD84

Claims (7)

[Claims] 1. An ultraviolet decomposition unit for irradiating a pollutant gas containing an organic compound with ultraviolet rays having a wavelength of less than 300 nm to decompose the organic compound, an acidic electrolyzed water supply pipe and an alkaline electrolyzed water supply pipe are respectively provided with valves. The intermediate product treatment for neutralizing and decomposing the intermediate product by selectively spraying strong alkaline electrolyzed water and strongly acidic electrolyzed water on the intermediate product produced by decomposition of the organic compound. And a device for decomposing a gaseous organic compound. 2. The intermediate product treatment device is provided in an intermediate portion of the ultraviolet decomposing unit, and strong alkaline electrolyzed water and strong acidic electrolyzed water are selectively sprayed to a pollutant gas in the ultraviolet decomposing unit. The apparatus for decomposing a gaseous organic compound according to 1. 3. The intermediate product treatment device is connected downstream of the ultraviolet decomposing unit, and strong alkaline electrolyzed water and strong acidic electrolyzed water are selectively sprayed onto the polluted gas passing through the ultraviolet decomposing unit. 1. The apparatus for decomposing a gaseous organic compound according to 1. 4. The apparatus for decomposing a gaseous organic compound according to claim 3, wherein the alkaline gas and / or the strongly acidic electrolyzed water is sprayed on the pollutant gas in the ultraviolet decomposition unit. 5. The ultraviolet decomposition unit comprises a decomposition cell having an ultraviolet irradiation lamp installed therein, and a gas inlet is formed in a peripheral wall of the decomposition cell so as to blow a pollutant gas along a diameter of the decomposition cell. The decomposition apparatus of the gaseous organic compound according to any one of claims 1 to 4. 6. The decomposition apparatus for a gaseous organic compound according to claim 5, wherein a plurality of the ultraviolet irradiation lamps are hung on the upper surface of the decomposition cell at equal intervals. 7. The apparatus for decomposing gaseous organic compounds according to claim 5, wherein the ultraviolet irradiation lamp is made of synthetic quartz glass whose protective tube transmits 80% or more of ultraviolet rays having a wavelength of 172 nm or more. .