JP3699055B2 - Equipment for decomposing gaseous organic compounds - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for decomposing gaseous organic compounds.
[0002]
[Prior art]
Organic compounds such as trichlorethylene and tetrachlorethylene have been used for many years as cleaning agents and solvents in the fields of semiconductors, metal oil cleaning, dry cleaning and the like due to their excellent dissolving power.
However, in recent years, it has been found that carcinogenic substances are present in these chlorinated organic compounds, and their harmfulness is regarded as a social problem and emission control has been brought about. Therefore, in business establishments that have used and discharged a large amount of these chlorinated organic compounds in the past, soil contamination and underground contamination in and around the site have become serious problems.
Moreover, when a pollutant gas contains a certain organic compound, a bad odor is emitted and the environment may be deteriorated.
[0003]
Usually, in order to purify the soil, the soil gas is sucked and the organic compounds contained therein are removed by adsorption with activated carbon. For this reason, a large-scale adsorbing device using activated carbon is required in a high-concentration and wide-area contaminated area, and the equipment cost burden and running cost are problematic.
In addition, if the organic compounds contained in the soil gas are to be adsorbed / removed only by activated carbon, it is necessary to frequently replace the activated carbon, resulting in enormous labor and costs associated with activated carbon replacement, regeneration, disposal, etc. As a result, the corporate burden of soil remediation has become very large.
[0004]
By the way, a technique for decomposing an organic compound by irradiating ultraviolet rays is conventionally known. For example, in the surface cleaning of a semiconductor wafer, an organic compound on the surface is decomposed by irradiating high-energy ultraviolet rays (wavelength 172 nm) with an excimer lamp or the like. doing. When irradiated with such high energy ultraviolet rays, the organic compound is decomposed in a very short time. However, the excimer lamp is extremely expensive, the equipment cost is enormous, and the power consumption is very large. Therefore, it is not practical to use it for the purification of soil gas.
[0005]
In addition, when an organic compound is decomposed by irradiating ultraviolet rays from an inexpensive low-pressure mercury lamp, medium-pressure mercury lamp, or high-pressure mercury lamp, reactive unstable substances such as hydrogen chloride and haloacetic acid are generated as intermediate products. It takes a very long time to decompose it into a stable substance.
Therefore, an organic chlorine compound that decomposes a reaction intermediate having chlorine atoms by irradiating a gas containing an organic chlorine compound with ultraviolet light including ultraviolet light having a wavelength of 300 nm or less, and further decomposes the reaction intermediate by microbial treatment. A decomposition method is disclosed in JP-A-8-24335.
However, although microbial treatment is excellent in terms of environmental friendliness, it is difficult to manage and the degradation rate is very slow, so that treatment takes time, and in particular, there is a problem that it cannot cope with high concentration contamination.
[0006]
[Problems to be solved by the invention]
The present invention is a gaseous organic compound that can decompose pollutant gas containing an organic compound efficiently and in a short time, can easily treat an intermediate product generated by ultraviolet decomposition, and can be reduced in equipment cost and running cost. It is an object of the present invention to provide a decomposition apparatus.
[0007]
[Means for Solving the Problems]
The apparatus for decomposing gaseous organic compounds of the present invention irradiates pollutant gases containing organic compounds with ultraviolet light having a wavelength of less than 300 nm. In addition, the acidic electrolyzed water supply pipe and the alkaline electrolyzed water supply pipe are connected via valves, respectively, to selectively spray strong alkaline electrolyzed water and strong acidic electrolyzed water. An ultraviolet decomposition unit for decomposing the organic compound; Said Acidic electrolyzed water supply pipe and Said Alkaline electrolyzed water supply pipe of Respectively In An intermediate that is connected through a valve and selectively sprays strongly alkaline electrolyzed water and strongly acidic electrolyzed water onto an intermediate product formed by decomposing the organic compound to neutralize and decompose the intermediate product. A product processing apparatus.
Organic compounds contained in polluted gases are separated by UV irradiation. Solution And The decomposition reaction is accelerated by the strong acidic electrolyzed water and the strong alkaline electrolyzed water. Also , A plurality of intermediate products generated as a result of decomposition of the organic compound are considered to be mixed in an unstable radical state by ultraviolet irradiation. These unstable gaseous intermediate products are gas-washed, neutralized, or decomposed by contact with sprays of strongly acidic electrolyzed water or strongly alkaline electrolyzed water to convert them into more stable and harmless substances. Can do. Moreover, strong alkaline electrolyzed water and strong acid electrolyzed water sprayed on the polluted gas are harmless to the human body, and there is no concern that the drainage pollutes the environment.
[0008]
Even if the intermediate product treatment apparatus is connected to the middle part of the ultraviolet decomposition unit and the strong alkaline electrolyzed water and the strong acidic electrolyzed water are selectively sprayed on the pollutant gas in the ultraviolet decomposition unit, the intermediate product treatment apparatus can be used. Strong alkaline electrolyzed water and strong acid electrolyzed water may be selectively sprayed on the polluted gas that is connected downstream of the ultraviolet decomposition unit and passes through the ultraviolet decomposition unit.
When the intermediate product treatment apparatus is connected downstream of the ultraviolet decomposition unit, strong alkaline electrolyzed water and / or strong acidic electrolyzed water may be sprayed on the contaminated gas in the ultraviolet decomposition unit.
With this configuration, the decomposition of the organic compound by ultraviolet rays is promoted, and the processing time is shortened. The strong alkaline electrolyzed water and strong acidic electrolyzed water sprayed on the ultraviolet decomposition unit are generated at the same time as the strong alkaline electrolyzed water and strong acidic electrolyzed water sprayed in the intermediate product treatment apparatus, so that an increase in cost can be suppressed.
[0009]
The ultraviolet decomposition unit includes a decomposition cell in which an ultraviolet irradiation lamp is installed, and a gas inlet may be formed in a peripheral wall of the decomposition cell so as to blow a contaminated gas along the diameter of the decomposition cell. This makes it difficult for the pollutant gas to move along the inner surface of the decomposition cell, increases the residence time of the pollutant gas in the decomposition cell, increases 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.
[0010]
In this case, a plurality of the ultraviolet irradiation lamps may be suspended from the upper surface of the decomposition cell at equal intervals so that the pollutant 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.
In order to prevent the ultraviolet rays having a relatively short wavelength from being attenuated, it is desirable that 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.
It is preferable to use a UV lamp that is as thin as possible, and a protective tube with a diameter of about 6 mm to 20 mm is used.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
The apparatus for decomposing gaseous organic compounds is connected to a gas suction apparatus for sucking pollutant gas containing organic compounds from contaminated soil, and as shown in FIG. 1 is provided with an intermediate product processing apparatus composed of a scrubber 2 connected downstream of 1, an activated carbon adsorption unit 3 connected downstream of the scrubber 2, and an electrolyzed water generating apparatus 4.
[0012]
The electrolyzed water generating device 4 uses an oxidizer Medica CL (trade name, manufactured by Miura Denshi Co., Ltd.), and the electrolyzed water generating device 4 electrically supplies water containing a water-soluble electrolyte such as sodium chloride, potassium chloride, and magnesium chloride. When decomposed, strong 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 strong alkaline electrolyzed water obtained in this way are harmless to the human body, so there is no concern of contaminating the environment even if they are brought into contact with contaminated gases as functional water.
[0013]
The ultraviolet decomposition unit 1 is configured by connecting two decomposition cells 6 in series with a plurality of ultraviolet irradiation lamps composed of low-pressure mercury lamps 5 (FIGS. 2 and 3) inside a stainless steel pipe.
The low-pressure mercury lamp 5 uses synthetic quartz glass that transmits 80% or more of ultraviolet rays having a wavelength of 172 nm or more as a protective tube, and irradiates ultraviolet rays having a wavelength of 254 nm and 185 nm with a power consumption of 13 W.
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 disposed at the center of the upper surface of the decomposition cell 6, and the rest are disposed at equal intervals on the peripheral edge of the upper surface. .
[0014]
As shown in FIG. 3, the contaminated gas is introduced from a gas inlet 7 formed at one end of the diameter at the upper peripheral wall of one decomposition cell 6, and formed at one end of the diameter at the upper peripheral wall of the other decomposition cell 6. The gas outlet 8 is taken out.
Then, the anode side of the electrolyzed water generating device 4 and each decomposition cell 6 of the ultraviolet decomposition unit 1 are connected by an acidic electrolyzed water supply pipe 9 and installed at a connection portion between the decomposition cell 6 and the acidic electrolyzed water supply pipe 9. When the valve is opened, strong acidic electrolyzed water is sprayed into the decomposition cell 6.
Further, the cathode side of the electrolyzed water generating device 4 and each decomposition cell 6 of the ultraviolet decomposition unit 1 are connected by an alkaline electrolyzed water supply pipe 10 and installed at a connection portion between the decomposition cell 6 and the alkaline electrolyzed water supply pipe 10. When the valve is opened, strong alkaline electrolyzed water is sprayed into the decomposition cell 6.
[0015]
Both ends of a circulation pipe 11 having a pump 12 are connected to the upper and lower portions of the scrubber 2, and the gas that has passed through the ultraviolet decomposition unit 1 and flows into the lower portion of the scrubber 2 is pushed up in the circulation pipe 11 by the pump 12. It is returned to the upper part of the scrubber 2 and circulates in the scrubber 2.
The scrubber 2 is provided with a pH measuring device 25, and the pH of the contaminated gas flowing into the scrubber 2 can be measured by the pH measuring device 25. Furthermore, 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 opens the valve according to the pH of the pollutant gas measured by the pH measuring device 25. Strongly acidic electrolyzed water and strong alkaline electrolyzed water are selectively sprayed on the gas circulating in the scrubber 2 to neutralize and decompose the intermediate product contained in the gas.
[0016]
In addition, a drainage neutralization tank 14 is installed in the drainage channel 13 extending from the scrubber 2, and an acid electrolyzed water supply pipe 9 and an alkaline electrolyzed water supply pipe 10 are connected to the drainage neutralization tank 14 through valves, respectively. The wastewater stored in the wastewater neutralization tank 14 is neutralized by adding strong alkaline electrolyzed water or strong acid electrolyzed water, and then discharging the water.
An activated carbon filter is built in the activated carbon adsorption unit 3, and minute residual compounds contained in the gas that has passed 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 clean gas that has passed through the activated carbon filter is exhausted.
[0017]
This apparatus for decomposing gaseous organic compounds is used as follows.
A polluted gas containing an organic compound sucked from the soil is introduced along the diameter into the ultraviolet decomposition unit 1 through the gas inlet 7, and the strongly acidic electrolyzed water and strong alkaline electrolyzed water generated by the electrolyzed water generating device 4 are used. Either or both are sprayed into the electrolysis cell 6 to come into contact with the contaminated gas, and the low-pressure mercury lamp 5 is turned on to irradiate the contaminated gas with ultraviolet rays.
Then, the organic compound contained in the polluted gas is decomposed by ultraviolet irradiation, and the decomposition reaction is promoted by the strong acidic electrolyzed water and / or the strong alkaline electrolyzed water.
[0018]
The contaminated gas taken out from the gas outlet 8 after passing through the ultraviolet decomposition unit 1 contains an intermediate product generated as a result of the decomposition of the organic compound, and the contaminated gas containing the intermediate product is removed from the scrubber 2. Flow into.
The polluted gas that has flowed into the scrubber 2 is measured for pH by the pH measuring device 25 and circulates in the scrubber 2 through the circulation pipe 11 for a predetermined time. Then, when passing through the circulation pipe 11, the strongly acidic electrolyzed water or the strongly alkaline electrolyzed water is sprayed on the contaminated gas according to the pH measured by the pH measuring device 25, and the intermediate product contained in the contaminated gas. Is neutralized.
[0019]
Depending on the organic compound contained in the pollutant gas, the pollutant gas containing the intermediate product may be neutral. In this case, spray the strong acid electrolyzed water and strong alkaline electrolyzed water at the same time to remove the intermediate product. Decompose.
Further, the organic compound remaining slightly after passing through the ultraviolet decomposition unit 1 is further decomposed by spraying strong acidic electrolyzed water or strong alkaline electrolyzed water. Part of the intermediate product that has not been decomposed or part of the by-product generated by neutralization is dissolved in the sprayed electrolyzed water and discharged to the drainage channel 13.
[0020]
Since the water discharged from the scrubber 2 to the drainage channel 13 is often acidic or alkaline, it is neutralized by adding strong alkaline electrolyzed water or strong acidic electrolyzed water in the wastewater neutralization tank 14 and then externally. To discharge.
The gas that has been circulated through the scrubber 2 for an integral time flows into the activated carbon adsorption unit 3 and adsorbs and removes slightly remaining intermediate products and organic compounds with an activated carbon filter, and then is exhausted to the outside.
[0021]
The ultraviolet decomposition unit 1 may be used as an intermediate product processing apparatus. In this case, each electrolysis cell 6 is provided with a pH measuring device 25, and the strongly acidic electrolyzed water is supplied from the connected acidic electrolyzed water supply pipe 9 and alkaline electrolyzed water supply pipe 10 according to the pH measured by the pH measuring device 25. And strong alkaline electrolyzed water is selected and sprayed to neutralize and decompose the intermediate product contained in the contaminated gas in the ultraviolet decomposition unit 1. And the strongly acidic electrolyzed water and strong alkaline electrolyzed water sprayed for neutralization will also decompose | disassemble the organic compound contained in pollution gas. At this time, the scrubber 2 may or may not be installed downstream of the ultraviolet decomposition unit 1.
Moreover, the acidic electrolyzed water supply pipe 9 and the alkaline electrolyzed water supply pipe 10 are not connected to the ultraviolet decomposition unit 1, but the organic compound contained in the pollutant gas in the ultraviolet decomposition unit 1 is decomposed only by ultraviolet rays, and then the scrubber 2 Strong alkaline electrolyzed water and strong acidic electrolyzed water may be selectively sprayed inside.
[0022]
(Example)
In the gaseous organic compound decomposition apparatus shown in FIG. 1, the decomposition cell 6 has a diameter of 200 mm and a length of 600 mm, and seven low-pressure mercury lamps 5 are set. Then, a contaminated gas containing trichlorethylene (hereinafter referred to as TCE) was introduced into the ultraviolet decomposition unit 1, and 100 ml of strongly acidic electrolyzed water having a pH of 2.1 to 2.4 was sprayed per minute.
The scrubber 2 was sprayed with 1 liter of strong alkaline electrolyzed water having a pH of 11.0 per minute, and polluted gas was circulated at a flow rate of 12.5 l / min.
[0023]
In Test 1, a pollutant gas having a TCE concentration of 50 ppm was blown into the gas inlet 7 of the ultraviolet decomposition unit 1 at an air volume of 400 l / min, and (1) immediately before the ultraviolet decomposition unit 1 and (2) between the ultraviolet decomposition unit 1 and the scrubber 2. , (3) Between the scrubber 2 and the activated carbon adsorption unit 3, (4) TCE concentration, hydrogen chloride concentration, phosgene concentration, chlorine concentration after 10 minutes and 30 minutes after the activated carbon adsorption unit 3 The ozone concentration was measured, and the result is shown in FIG. Moreover, the result of having measured the pH in the scrubber 2 at the start of the test, 10 minutes later, and 30 minutes later is shown in FIG.
[0024]
In Test 2, a pollutant gas with a TCE concentration of 100 ppm was blown into the gas inlet 7 at an air volume of 400 l / min. As in Test 1, there were four points (1), (2), (3), and (4). Then, after 10 minutes and 30 minutes, TCE concentration, hydrogen chloride concentration, phosgene concentration, chlorine concentration, ozone concentration are measured, and the pH in the scrubber 2 is measured at the start of the test, after 10 minutes, and after 30 minutes. The measurement results are shown in FIGS. 6 and 7, respectively.
From the results of Test 1 and Test 2, it was found that TCE contained in the pollutant gas was almost decomposed by ultraviolet irradiation, and the remaining organic compounds were also decomposed to a very low concentration while circulating through the scrubber 2.
In addition, most of the intermediate products generated as a result of decomposing organic compounds by UV irradiation are neutralized in the scrubber 2, and the extremely small organic compounds and intermediate products contained in the gas that has passed through the scrubber 2 are also adsorbed by activated carbon. It was found that unit 3 was completely removed by adsorption.
[0025]
Furthermore, in Test 3 to Test 9, using the ultraviolet decomposition unit 1, among the seven kinds of organic compounds, hydrogen sulfide, acetaldehyde, pyridine, ammonia, trimethylamine, acetic acid and methyl mercaptan, which are called seven major malodorous substances, Contaminated gas with a concentration of 10 ppm was blown into the gas inlet 7 at an air flow rate of 400 l / min, and the organic compound concentration was measured at four locations (1), (2), (3), and (4) as in Test 1. , (2), (3), (4), the intermediate product concentration was measured.
In test 3, hydrogen sulfide (H ₂ A decomposition test was performed on the contaminated gas containing S), and strong alkaline electrolyzed water was sprayed onto the scrubber 2, and the concentration was measured immediately after starting the test, after 10 minutes, 30 minutes, 50 minutes and 90 minutes.
H in FIG. ₂ The change in S concentration over time is shown in FIG. ₂ The time-dependent changes in concentration and ozone concentration are shown respectively.
[0026]
In test 4, acetaldehyde (CH ₃ Contaminated gas containing COH) was flowed, and strongly acidic electrolyzed water was sprayed onto the scrubber 2, and the concentration was measured immediately after starting the test, after 10 minutes, after 30 minutes and after 50 minutes. FIG. 10 shows the acetaldehyde concentration, and FIG. 11 shows the acetic acid (CH3COOH) concentration and ozone concentration expected as intermediate products. Although acetic acid was predicted as an intermediate product, as can be seen from FIG. 11, since the acetic acid is hardly contained in the contaminated gas after passing through the ultraviolet decomposition unit 1, neutralization decomposition of acetic acid is considered. There seems to be no need.
[0027]
Test 5 consists of pyridine (C ₅ H ₅ Contaminated gas containing N) was blown into the gas inlet 7 and strong acidic electrolyzed water was sprayed onto the scrubber 2, and the concentration was measured immediately after starting the test, after 10 minutes, after 30 minutes and after 50 minutes. FIG. 12 shows the pyridine concentration, and FIG. 13 shows the NOx concentration and the ozone concentration expected as intermediate products.
In test 6, ammonia (NH ₃ ) Was introduced into the gas inlet 7 and strongly acidic electrolyzed water was sprayed onto the scrubber 2, and the concentration was measured immediately after starting the test, after 10 minutes, after 30 minutes and after 50 minutes. FIG. 14 shows ammonia concentration, and FIG. 15 shows NOx concentration and ozone concentration expected as intermediate products.
[0028]
In test 7, trimethylamine ((CH ₃ ) ₃ A polluted gas containing N) was flowed, and strongly acidic electrolyzed water was sprayed onto the scrubber 2, and the concentration was measured immediately after starting the test, after 10 minutes, after 30 minutes and after 50 minutes. FIG. 16 shows the trimethylamine concentration, and FIG. 17 shows the NOx concentration and the ozone concentration expected as intermediate products. In addition, although ammonia was expected as an intermediate product, it was difficult to distinguish from trimethylamine, and the concentration could not be measured.
In tests 5 to 7, NOx was predicted as an intermediate product. However, since NOx is hardly contained in the polluted gas after passing through the ultraviolet decomposition unit 1, the neutralization decomposition need not be considered. I think that the.
[0029]
In test 8, acetic acid (CH ₃ A contaminated gas containing COOH) was introduced into the gas inlet 7, and strong alkaline electrolyzed water was sprayed onto the scrubber 2, and the concentration was measured immediately after starting the test, after 10 minutes, 30 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 Contaminated gas containing SH) was introduced into the gas inlet 7, sprayed with strong alkaline electrolyzed water on the scrubber 2, and the concentration was measured immediately after starting the test, after 10 minutes, 30 minutes and 50 minutes. FIG. 20 shows the methyl mercaptan concentration, and FIG. 21 shows the SO expected as an intermediate product. ₂ Concentration, H ₂ S concentration and ozone concentration are shown. In this test, H expected as an intermediate product ₂ S was not detected from the gas after passing through the ultraviolet unit 1.
From the results of Test 3 to Test 9, it was found that malodorous substances can be almost decomposed by the decomposition apparatus of the present invention.
[0030]
In the test 10, in order to investigate the organic compound decomposition effect of ultraviolet rays, as shown in FIG. 22, a test cell 19 having a volume of 180 l with 10 ultraviolet lamps 18 suspended from the upper surface is installed downstream of the gas mixing tank 17. A test apparatus having VOC monitors 20 installed on the upstream side and the downstream side of the test cell 19 is prepared, and a contaminated gas with a TCE concentration of 50 ppm is added to this apparatus at 100 l / min, 200 l / min, 300 l / min, 400 l / min. Continuously fed. Then, in the pattern in which 10 UV lamps 18 are lit, 1 in 7 lit patterns, 2 in 6 lit patterns, 3 in 3 lit patterns, 4 in 1 lit pattern 5, the upstream side of the UV decomposition unit 2 ' The results of measuring the TCE concentration on the downstream side are shown in FIG. Further, the TCE decomposition rate is obtained by the equation of (1−downstream concentration / upstream concentration) × 100% and shown in FIG.
[0031]
In Test 11, an experiment was performed in the same manner as in Test 10 except that tetrachloroethylene (PCE) was used instead of TCE. The results of measuring the PCE concentration are shown in FIG. 25, and the PCE decomposition rate is shown in FIG.
Test 12 was conducted in the same manner as 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. The results are shown in FIG. 27 and the cis-1,2-DCE decomposition rate is shown in FIG.
[0032]
In Test 13, an experiment was performed in the same manner as in Test 10 except that monochloroethylene was used instead of TCE. The results of measuring the monochloroethylene concentration are shown in FIG. 29, and the monochloroethylene decomposition rate is shown in FIG.
Test 14 was performed in the same manner as Test 10 except that ethyl acetate was used in place of TCE. The results of measuring the ethyl acetate concentration are shown in FIG. 31 and the ethyl acetate decomposition rate is shown in FIG.
In Test 15, a gas having a toluene concentration of 50 ppm using toluene instead of TCE was supplied to a test apparatus similar to Test 10 at 100 l / min, and the result of measuring the toluene concentration is shown in FIG.
From the results of Test 10 to Test 15, the lower the test flow rate, the higher the ultraviolet night decomposition rate, tetrachlorethylene with a large number of chlorines is easily decomposed by ultraviolet rays, and ethyl acetate and toluene that do not contain chlorine are difficult to be decomposed by ultraviolet rays. I understand.
[0033]
In order to investigate the decomposition promoting effect when spraying strong alkaline electrolyzed water, strongly acidic electrolyzed water, or a mixed water thereof and irradiating with ultraviolet rays, test 16 was performed. In test 16, as shown in FIG. 34, an ultraviolet lamp 18 that irradiates ultraviolet light having an output of 30 W and a wavelength of 254 nm is installed in a test cell 19 having an inner diameter of 120 mm and a height of 1300 mm, and TCE gas and dilution air are mixed. The introduced gas was introduced into the test cell 19 at a flow rate of 3 l / min. Further, using the atomizer 21, either strong acidic electrolyzed water, strong alkaline electrolyzed water, mixed water obtained by mixing strong acidic electrolyzed water and strong alkaline electrolyzed water 1: 1, or tap water is supplied into the test cell 19 by 10 l. After spraying at / min and the TCE concentration was stabilized, the ultraviolet lamp 18 was repeatedly turned on and off, and the TCE concentration of the gas collected 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 is clear that spraying strongly acidic electrolyzed water, strong alkaline electrolyzed water, mixed water of strong acid electrolyzed water and strongly alkaline electrolyzed water clearly increases the decomposition efficiency compared to the case of spraying tap water. It was.
[0034]
In the test 17, a test apparatus as shown in FIGS. 36 and 37 is used. This test apparatus has a test cell 19 on which an exchangeable ultraviolet lamp 18 is suspended. A first gas inlet 7a for introducing gas along the diameter and a second gas inlet 7b for introducing gas along the tangent are formed at the lower peripheral wall of the test cell 19, and the test cell 19 is formed. A first gas outlet 8a for extracting gas along the diameter is formed at the upper portion of the peripheral wall, and a second gas outlet 8b for extracting gas along the tangent is formed.
[0035]
Then, an ultraviolet lamp 18 with an output of 13 W that irradiates ultraviolet rays with a wavelength of 185 nm and an ultraviolet wavelength of 254 nm with a protective cylinder, or an ultraviolet lamp 18 with an output of 40 W that irradiates ultraviolet rays with a wavelength of 185 nm and ultraviolet rays with a wavelength of 254 nm without a protective cylinder. Used, a gas having a TCE concentration of 50 ppm was passed through the flow path (1) from the first gas inlet 7a to the first gas outlet 8a at flow rates of 100 l / min, 200 l / min, 300 l / min, and 400 l / min. And the TCE concentration on the upstream side and the downstream side of the test cell 19 are measured for the case of passing through the flow path (2) from the second gas inlet 7b to the second gas outlet 8b, and the TCE decomposition rate is obtained. It was. The result is shown in FIG.
[0036]
From the results of Test 17, it was found that when the contaminated gas was introduced into the cell along the diameter thereof toward the center of the cross section, the decomposition efficiency was higher than when introduced along the tangential direction.
This is presumably 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 time for staying in the cell is shortened.
[0037]
FIG. 39 shows a test apparatus used for Test 18 to Test 20. In this test apparatus, a Tedlar bag 23 containing test gas is connected to a test cell 19 having an inner diameter of 45 mm, a length of 500 mm, and a volume of 800 ml containing an ultraviolet lamp 18, and a pump 24 sucks the gas until a constant concentration is obtained. The test cell 19 was introduced. Then, the ultraviolet lamp 18 was turned on for 20 minutes, and the change in gas concentration was observed with the VOC sensor 20. As the ultraviolet lamp 18, Toshiba GLS6UN that irradiates ultraviolet light with a wavelength of 185 nm and ultraviolet light with a wavelength of 254 nm, Toshiba GLS6UJ that irradiates ultraviolet light with a wavelength of 254 nm, and a black light (manufactured by Miyata Elevum) that irradiates ultraviolet light with a wavelength of 300 nm or more are used. The test was conducted for a gas concentration of 10 ppm and 100 ppm.
[0038]
In Test 18, trichlorethylene is used as the test gas, and the TCE concentration when the initial gas concentration is 10 ppm is shown in FIG. 40 (a), and the TCE concentration when 100ppm is shown in FIG. 40 (b).
Test 19 uses tetrachlorethylene as a test. FIG. 41 (a) shows the PCE concentration when the initial gas concentration is 10 ppm, and FIG. 41 (b) shows the PCE concentration when it is 100 ppm.
In Test 20, cis-1,2-dichloroethylene was used as a test gas, and the cis-1,2-DCE concentration when the initial gas concentration was 10 ppm was shown in FIG. The -1,2-DCE concentrations are shown in FIG.
From the results of Test 18 to Test 20, it was found that when the wavelength of the ultraviolet light was 300 nm or more, the concentration did not change substantially the same as the blank measurement value, and the organic compound was not decomposed.
[0039]
In Test 21, Yperit (ClCH), a poison gas for chemical weapons. ₂ CH ₂ ) ₂ The possibility of the ultraviolet decomposition effect of S) was verified. An ultraviolet lamp that irradiates ultraviolet rays having a wavelength of 185 nm and 254 nm was placed in 500 ml of durambin, and chloromethyl methyl sulfide (ClCH ₂ SCH ₃ , Hereinafter referred to as CMMS) was connected to this durambin and sucked with a separately connected pump to replace the air in durumbin with CMMS. Thereafter, the UV lamp was turned on to measure the CMMS concentration, and the result is shown in FIG.
Test 21 showed that although the degradation rate was not so fast, the yperit mimetic could be degraded to about half by ultraviolet irradiation.
[0040]
【The invention's effect】
According to the inventions according to claims 1 to 3, harmful organic compounds contained in the polluted gas are converted into relatively high energy ultraviolet rays having a wavelength of less than 300 nm. Strongly alkaline electrolyzed water and strong acid electrolyzed water selectively sprayed with The resulting unstable intermediate product is neutralized and decomposed with strong alkaline electrolyzed water and strongly acidic electrolyzed water, so that the treatment time is short and a large-scale apparatus is not required.
An organic compound that cannot be decomposed by ultraviolet irradiation can be decomposed to a lower level by spraying strong alkaline electrolyzed water or strongly acidic electrolyzed water. Furthermore, strong alkaline electrolyzed water and strongly acidic electrolyzed water are harmless to the human body, so there is no fear of polluting the environment.
[0041]
According to the invention which concerns on Claim 4, decomposition | disassembly of the organic compound in an ultraviolet decomposition unit is accelerated | stimulated, and processing time can be shortened further.
According to the fifth aspect of the invention, the time during which the pollutant gas stays in the decomposition cell is lengthened, and the intensity of ultraviolet irradiation with respect to the pollutant gas is increased, so that the decomposition efficiency is further improved.
According to the sixth aspect of the present invention, the pollutant gas is irradiated with ultraviolet rays uniformly and with high intensity, so that the organic compound decomposition efficiency is good.
According to the seventh aspect of the invention, since the ultraviolet light having a short wavelength is irradiated to the contaminated gas without being blocked by the protective cylinder, the organic compound can be decomposed in a short time.
[Brief description of the drawings]
FIG. 1 is a schematic view of an apparatus for decomposing gaseous organic compounds showing an embodiment of the present invention.
FIG. 2 is a sectional side view of a decomposition cell.
FIG. 3 is a cross-sectional plan view of a decomposition cell
FIG. 4 is a diagram showing the measurement results of contamination concentration in Test 1
FIG. 5 is a diagram showing pH measurement results in Test 1
FIG. 6 is a diagram showing the result of measuring the contamination concentration in Test 2
FIG. 7 is a diagram showing pH measurement results in Test 2
FIG. 8 is a graph showing the change over time of the organic compound concentration in Test 3.
FIG. 9 is a graph showing the change over time in the intermediate product concentration in Test 3.
FIG. 10 is a graph showing the change over time in the organic compound concentration in Test 4.
FIG. 11 is a graph showing the change over time in the concentration of intermediate product compounds in Test 4.
FIG. 12 is a graph showing the change over time in the organic compound concentration in Test 5.
FIG. 13 is a graph showing the change over time in the intermediate product concentration in Test 5.
FIG. 14 is a graph showing changes with time in organic compound concentration in Test 6;
FIG. 15 is a graph showing changes with time in organic compound concentration in Test 6;
FIG. 16 is a graph showing changes with time in organic compound concentration in Test 7;
FIG. 17 is a graph showing the change over time in the intermediate product concentration in Test 7;
FIG. 18 is a graph showing the change over time in the organic compound concentration in Test 8.
FIG. 19 is a graph showing the change over time in the intermediate product concentration in Test 8.
FIG. 20 is a graph showing the change over time in organic compound concentration in Test 9;
FIG. 21 is a graph showing the change over time in the intermediate product concentration in Test 9.
FIG. 22 is a schematic diagram of a test apparatus used in Test 10 to Test 15.
FIG. 23 is a graph showing measurement results of TCE concentration in Test 10;
FIG. 24 is a diagram showing a calculation result of a TCE decomposition rate in Test 10;
FIG. 25 is a diagram showing measurement results of PCE concentration in Test 11;
FIG. 26 is a diagram showing the calculation result of the PCE decomposition rate in Test 11;
FIG. 27 is a graph showing 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 graph showing measurement results of monochlorobenzene concentration in Test 13;
FIG. 30 is a diagram showing the calculation result of the monochlorobenzene decomposition rate in Test 13;
FIG. 31 is a graph showing measurement results of ethyl acetate concentration in Test 14;
FIG. 32 is a graph showing the calculation result of the ethyl acetate decomposition rate in Test 14;
FIG. 33 is a graph showing the measurement results of toluene concentration in Test 15;
FIG. 34 is a schematic diagram of a test apparatus used in Test 16.
FIG. 35 is a graph showing the 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 cross-sectional plan view of the test cell used in Test 17
FIG. 38 is a graph showing the TCE decomposition rate in Test 17
FIG. 39 is a schematic diagram of an apparatus used for Test 18 to Test 20.
FIG. 40 is a graph showing the change over time in the TCE concentration in Test 18;
FIG. 41 is a graph showing the change over time in the PCE concentration in Test 19;
FIG. 42 is a graph showing the change over time in the cis-1,2-DCE concentration in Test 20;
FIG. 43 is a graph showing changes 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 outlet
9 Acidic electrolyzed water supply pipe
10 Alkaline electrolyzed water supply pipe
11 Circulation pipe
12 Pump
13 Drainage channel
14 Wastewater neutralization tank
15 fans
16 Exhaust pipe
17 Mixture tank
18 UV lamp
19 Test cell
20 VOC sensor
21 Atomizer
22 Sampling port
23 Tedlar Bag
24 pump
25 pH measuring device

Claims (7)

Irradiate ultraviolet rays with a wavelength of less than 300 nm to polluted gases containing organic compounds, and acid electrolyzed water supply pipes and alkaline electrolyzed water supply pipes are connected via valves, respectively, to select strong alkaline electrolyzed water and strong acidic electrolyzed water manner and the spray to the organic compound decomposing ultraviolet cracking unit, connected via a valve to each of the acidic electrolytic water supply pipe and the alkaline electrolytic water supply pipe, an intermediate of the organic compound is generated is decomposed Decomposing a gaseous organic compound characterized by comprising an intermediate product treatment device for neutralizing and decomposing the intermediate product by selectively spraying the product with strong alkaline electrolyzed water and strong acidic electrolyzed water apparatus. The gaseous organic compound decomposition apparatus according to claim 1, wherein the intermediate product treatment apparatus is provided in an intermediate portion of the ultraviolet decomposition unit. The gaseous organic compound decomposition apparatus according to claim 1, wherein the intermediate product processing apparatus is connected downstream of the ultraviolet decomposition unit.   4. The apparatus for decomposing a gaseous organic compound according to claim 3, wherein strongly alkaline electrolyzed water and / or strongly acidic electrolyzed water is sprayed on the contaminated gas in the ultraviolet decomposition unit.   5. The ultraviolet decomposition unit includes 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 contaminated gas along the diameter of the decomposition cell. The decomposition apparatus of the gaseous organic compound in any one of.   The gaseous organic compound decomposition apparatus according to claim 5, wherein the plurality of ultraviolet irradiation lamps are suspended from the upper surface of the decomposition cell at equal intervals.   7. The apparatus for decomposing a gaseous organic compound 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.

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