JP4471684B2 - Gas decomposition processing equipment - Google Patents

Description

The present invention relates to a gas decomposition treatment apparatus using ozone and an ozone decomposition catalyst, and can be preferably used for purification of a gas to be treated containing, for example, a volatile organic substance (VOC) such as hydrocarbons as a component gas to be treated. The present invention relates to a gas decomposition treatment apparatus .

  As a device that decomposes malodorous components such as hydrocarbons and other volatile organic substances (VOC) and sulfur compounds using ozone and an ozone decomposition catalyst, the ozone decomposition catalyst is heated with a heater or the like to dehumidify the activity of the catalyst. Some have improved the adsorption capacity and decomposition efficiency of malodorous components (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 53-30978 (page 2)

  In the conventional apparatus or the conventional method as described above, the odor decomposition component can be decomposed with high efficiency by heating the ozone decomposition catalyst and increasing the adsorption and decomposition ability of the catalyst. There was a problem that carbon monoxide, which is a harmful component, was produced as a by-product.

  The present invention has been made to solve the above-mentioned problems of the prior art, and can efficiently decompose malodorous components such as volatile organic compounds (VOC) contained in the gas to be treated. An object of the present invention is to provide a gas decomposition treatment apparatus and a gas decomposition treatment method which do not cause a risk of emission of harmful carbon monoxide by-produced by decomposition.

The gas decomposition processing apparatus according to the present invention is a gas decomposition processing apparatus that decomposes a component gas to be processed contained in a gas to be processed using ozone and an ozone decomposition catalyst. A moisture controller that controls the concentration of water contained therein , and a gas sensor that can detect carbon monoxide and carbon dioxide, which is provided at a subsequent stage of the ozone decomposition catalyst, and the moisture regulator is a detection result of the gas sensor. The water content contained in the gas to be treated is controlled according to the above.
Further, the gas decomposition treatment apparatus according to the present invention is a gas decomposition treatment apparatus for decomposing a treatment component gas contained in a treatment gas using ozone and an ozone decomposition catalyst, wherein the treatment target is preceded by the ozone decomposition catalyst. A gas sensor provided with a moisture regulator for controlling the concentration of moisture contained in the gas and capable of detecting all carbon provided in the subsequent stage of the ozone decomposition catalyst, and the carbon of the component gas to be treated according to the detection result of the gas sensor And an ozone controller for controlling the amount of ozone input so that the concentration is 1 to 3 times the ozone necessary for decomposition.

In this invention, a moisture regulator for controlling the moisture concentration contained in the gas to be treated is provided before the ozone decomposition catalyst, and control is performed according to the detection result of the gas sensor provided at the subsequent stage of the ozone decomposition catalyst. Accordingly, with decomposing the malodorous components with high efficiency, it is possible to reduce the generation of carbon monoxide, can provide a gentle gas decomposition treatment equipment in the environment.

Embodiment 1 FIG.
FIG. 1 is a configuration diagram schematically showing a gas decomposition apparatus according to Embodiment 1 of the present invention. In the figure, a gas to be processed 1 containing a malodorous component such as VOC as a component gas to be processed is supplied to a flow path 21 comprising, for example, a duct and the like, and a moisture regulator 2 for controlling the water concentration in the gas to be processed 1. After the moisture concentration is adjusted by the above, a processing chamber 6 containing an ozone decomposition catalyst 5 which is mixed with ozone supplied from an ozone generator 3 that generates ozone and adsorbs and decomposes a component gas to be processed using ozone. To be subjected to decomposition treatment of the component gas to be treated such as malodorous component. The ozone generator 3 uses air or oxygen as the raw material gas 4. A thick solid line arrow indicates the direction of gas flow such as gas to be processed and ozone.

The moisture controller 2 used in the first embodiment has the ability to control the moisture concentration contained in the gas 1 to be processed in the range of about 0.1 to 100 g / m ³ . The ozone decomposition catalyst 5 is a honeycomb-structured catalyst having the ability to adsorb to-be-processed component gases such as malodorous components and the ability to decompose ozone, and has porous alumina (Al ₂ O) in the skeleton. ₃ ) A ceramic material made of silica (SiO ₂ ) is used, and a highly active Mn-based catalyst component is dispersedly supported. The number of honeycombs of the ozone decomposition catalyst 5 was set to 500 cells / inch ² .

  A gas to be treated including a gas to be treated such as a malodorous component introduced into the ozone decomposition catalyst 5 is adsorbed on the ozone decomposition catalyst 5 and concentrated. Further, ozone is decomposed into oxygen atoms and oxygen molecules at the interface of the ozone decomposition catalyst 5, and the oxygen molecules diffuse into the gas phase, but the oxygen atoms are present on the catalyst surface. Since this oxygen atom has a stronger oxidizing power than ozone, it decomposes component gases such as malodorous components concentrated in the ozone decomposition catalyst 5. The by-product after decomposing the malodorous component is discharged from the processing chamber 6 as a processing gas 22. Hereinafter, Example 1 will be described more specifically, including experimental results obtained by examining the discharged gas with a gas analyzer.

Example 1
FIG. 3 shows the absolute humidity of the gas to be treated containing toluene as the gas to be treated, which was obtained by the experiment performed using the gas decomposition treatment apparatus shown in FIG. 1 (or FIG. 2 according to Embodiment 2). toluene degradation rate for, and is a characteristic diagram showing the relationship between carbon dioxide concentration / carbon monoxide concentration (CO ₂ concentration / CO concentration).
Here, the conditions of ozone decomposition catalyst (75 × 75 × 50 mmt), catalyst temperature of the ozone decomposition catalyst 50 ° C., gas flow rate 20 slm, linear velocity 6 cm / s, residence time 0.8 seconds, toluene concentration 100 ppm, ozone concentration 1000 ppm Below, the water concentration contained in the gas to be treated was controlled, and the by-products generated after the decomposition of toluene were examined.

Toluene was completely decomposed at an absolute humidity of 0 g / m ³ . However, the total of carbon monoxide and carbon dioxide was about 50% in terms of the number of carbon atoms contained in the initial toluene. For this reason, it is considered that toluene was not decomposed into carbon monoxide or carbon dioxide, and aldehydes and the like were produced. On the other hand, at an absolute humidity of about 7 g / m ³ , the toluene decomposition rate slightly decreased, but the decomposition rate was 90% or more. Moreover, the by-product after decomposition | disassembly could not confirm the production | generation of the aldehydes which are harmful components, but was only carbon monoxide and carbon dioxide. At an absolute humidity of about 20 g / m ³ , the toluene decomposition rate was reduced to about 80%. Furthermore, it is considered that toluene adsorbed on the catalyst decreased due to an increase in the moisture concentration in the gas 1 to be treated. Moreover, the by-products after the decomposition of toluene were only carbon monoxide and carbon dioxide.

Next, the gas concentration produced in the presence of moisture was evaluated by the ratio of the carbon dioxide concentration to the carbon monoxide concentration, that is, the parameter of carbon dioxide concentration / carbon monoxide concentration. That is, the degree of oxidation promotion from carbon monoxide to carbon dioxide was examined. As a result, although the carbon dioxide concentration / carbon monoxide concentration in the water concentration of about 5 g / m ³ or less in 1 the gas to be treated was approximately 2-4, changing the water concentration of about 5 to 20 g / m ³ And the carbon dioxide concentration / carbon monoxide concentration was found to rise to about 7. That is, it was found that the oxidation reaction of malodorous components to carbon dioxide can be controlled by controlling the water concentration in the gas 1 to be treated.

However, if the water concentration in the gas 1 to be treated becomes excessively high, the adsorption sites / reaction sites where the malodorous components are adsorbed are occupied by water, so that the amount of malodorous component adsorption decreases. For this reason, it is thought that the decomposition efficiency of the malodorous component, which is the original priority function, is lowered by reducing the collision probability with oxygen atoms. Therefore, the water concentration contained in the gas 1 to be treated is preferably controlled to about 5 to 20 g / m ³ , more preferably about 8 to 15 g / m ³ . When the water concentration is in the above range, the malodorous component can be decomposed with high efficiency, and the decomposed malodorous component is promoted to carbon dioxide. As a result, the by-product after decomposition does not contain harmful components, and malodorous components can be completely decomposed into carbon dioxide.

In addition, since the moisture controller 2 keeps the moisture concentration in the gas 1 to be treated in an optimal range, it can maintain a constant performance regardless of the season and climate such as winter when the relative humidity decreases.
In this embodiment, the temperature of the ozone decomposition catalyst 5 is set to 50 ° C., but the present invention is not limited to this. For example, similar decomposition characteristics can be obtained even at room temperature (around 20 ° C.). In this case, since a means for heating and keeping the catalyst is unnecessary, a low-cost apparatus is realized.
Furthermore, in this embodiment, the Mn-based catalyst component is dispersed and supported on the ozone decomposition catalyst 5, but is not limited to this. For example, in addition to manganese as the main component, TiO ₂ , palladium, Pt, Cu At least one substance selected from Co, Ni, Ag, etc. may be added, and it can be resistant to catalyst poisoning and maintain the decomposition performance for a long time.

When the flow rate of the gas to be processed 1 increases, it is necessary to suppress pressure loss that occurs before and after the ozone decomposition catalyst 5. As a method for solving this, an ozonolysis catalyst 5 having a honeycomb structure can be used. The number of honeycombs is 100 to 1000 cells / inch ² , more preferably 300 to 800 cells / inch ² . By setting the number of honeycombs within the above range, pressure loss can be reduced with respect to the gas flow rate, and malodorous components can be decomposed with high efficiency. When the number of honeycombs is more than 1000 cells / inch ² , the pressure loss becomes large, which is not preferable for the apparatus. Moreover, if the number of honeycombs is less than 100 cells / inch ^2, it is not preferable because the adsorption capacity and decomposition efficiency of malodorous components are reduced.

  The ability of the ozonolysis catalyst 5 that adsorbs malodorous components to adsorb malodorous components increases as its volume increases. However, when put into practical use, the apparatus becomes large and expensive in terms of cost. Therefore, it is desirable that the ozone decomposition catalyst 5 has a minimum volume capable of decomposing malodorous components. As an index for determining the volume of the ozonolysis catalyst 5, there are a linear velocity and a residence time. The linear velocity indicates the ratio of the catalyst cross-sectional area to the flow rate of the gas to be processed. The residence time is a time during which the malodorous component stays in the ozone decomposition catalyst 5 with respect to the traveling direction of the gas 1 to be treated. The total amount adsorbed on the surface increases.

  The volume of the ozone decomposition catalyst 5 necessary for obtaining a high decomposition rate of malodorous components varies depending on the processing flow rate of the gas 1 to be processed. As the linear velocity increases, the malodor component decomposition efficiency tends to decrease. Therefore, the linear velocity is preferably about 50 cm / s or less. When the linear velocity is about 50 cm / s or less, malodorous components can be efficiently decomposed. However, if it is faster than about 50 cm / s, the decomposition efficiency of malodorous components tends to decrease, and the pressure loss increases, which is not desirable.

  Further, the volume of the ozone decomposition catalyst 5 should be determined so that the residence time is about 0.01 to 1 second, more preferably about 0.1 to 0.5 second. If the residence time is in the range of about 0.1 to 0.5 seconds, malodorous components can be decomposed with high efficiency. When the residence time is shorter than about 0.01 seconds, the decomposition efficiency of malodorous components and the decomposition efficiency of ozone leaking to the latter stage of the catalyst tend to decrease. If it is longer than about 0.5 seconds, the decomposition efficiency of the malodorous component is substantially constant, but the volume of the ozone decomposition catalyst 5 increases, which is not desirable because it becomes expensive as a gas purification device.

  In general, when a malodorous component is decomposed using a catalyst, the temperature is increased in order to activate the catalyst. However, it has been found that the decomposition efficiency of malodorous components decreases when the temperature of the catalyst is 100 ° C. or higher in this method. This can be attributed to the following factors. Since ozone is ineffectively consumed due to the high temperature of the catalyst, ozone that reacts with malodorous components decreases. As a result, it is considered that the decomposition efficiency of malodorous components decreases. Further, if the malodorous component is a volatile substance such as VOC, the boiling point is low, and it may be desorbed from the catalyst and not decomposed. For this reason, the catalyst temperature is desirably less than 100 ° C. However, if the catalyst is below room temperature, the reaction rate constant decreases, so it is considered that the catalyst cannot be decomposed efficiently. Therefore, since the malodorous substance can be efficiently decomposed at a catalyst temperature of room temperature or higher, the catalyst temperature is preferably maintained at about 20 to 100 ° C.

In Example 1, although the example which decomposed | disassembled toluene as a malodorous component was given, it is not limited to this, For example, it is object by PRTR methods, such as xylene, styrene, formaldehyde, acetaldehyde, hexane, octane, methyl mercaptan. It has the same decomposition performance with respect to all the organic compounds, and the water concentration contained in the gas to be treated 1 is controlled to about 5 to 20 g / m ³ , more preferably about 8 to 15 g / m ^3. A good malodor component decomposition rate of 90% or more was obtained. Moreover, the production of harmful substances such as carbon monoxide could not be confirmed.

As described above, according to the first embodiment of the present invention, the moisture concentration contained in the gas to be treated is absolute in the moisture regulator 2 before the mixed gas of ozone and malodorous component is introduced into the ozone decomposition catalyst. The humidity is controlled to about 5 to 20 g / m ³ , more preferably about 8 to 15 g / m ³ . By optimizing the moisture concentration contained in the gas to be treated, aldehydes and carbon monoxide that may be generated after decomposition of malodorous components can be completely decomposed to carbon dioxide, which is a harmful component. It is possible to suppress emissions of aldehydes and carbon monoxide. Furthermore, the ozone concentration to be introduced is controlled to about 1 to 3 times, more preferably about 1.5 to 2.5 times the number of carbon atoms contained in one molecule of malodorous component, thereby efficiently degrading malodorous substances. In addition, the leaked ozone can be reduced downstream of the catalyst. Moreover, since ozone with a high production cost can be used efficiently, a gas decomposition treatment apparatus and a gas decomposition treatment method that are low in both initial cost and running cost can be obtained. In addition, by controlling the absolute humidity, it is possible to keep the moisture concentration contained in the gas to be processed within a predetermined preferable range regardless of the season, the weather, or the like.

Embodiment 2. FIG.
FIG. 2 is a block diagram schematically showing a gas decomposition treatment apparatus according to Embodiment 2 of the present invention. In the figure, 7 is a gas sensor for detecting the concentrations of carbon monoxide and carbon dioxide contained in the processing gas 22, and the moisture regulator 2 has a built-in controller not shown. The absolute humidity in the gas to be processed 1 is controlled according to the detection result. The gas sensor 7 should have a relatively excellent time response. For example, a known general sensor such as an infrared absorption method, a semiconductor method, or a multilayer method can be used. By using the gas sensor 7 capable of detecting carbon monoxide and carbon dioxide in the processing gas 22, the carbon monoxide concentration, carbon dioxide concentration, or carbon dioxide concentration / carbon monoxide concentration generated after decomposition of the malodorous component is determined. To detect. Note that a total hydrocarbon meter capable of measuring carbon atoms other than carbon monoxide and carbon dioxide may be used. A broken line indicates a signal path from the gas sensor 7. Since other configurations are the same as those of the first embodiment, description thereof is omitted. Further, the same reference numerals denote the same or corresponding parts throughout the drawings.

  The to-be-treated gas 1 containing a malodorous component is mixed with ozone supplied from the ozone generator 3 and introduced into an ozone decomposition catalyst 5 provided in the processing chamber 6. The malodorous component is adsorbed on the ozone decomposition catalyst 5 and concentrated. In addition, ozone is decomposed into oxygen atoms and oxygen molecules by the ozone decomposition catalyst 5, oxygen atoms are adsorbed on the catalyst, and oxygen molecules diffuse into the gas phase. Since oxygen atoms have stronger oxidizing power than ozone, they decompose malodorous components adsorbed on the ozone decomposition catalyst 5. The decomposed malodorous component is discharged from the processing chamber 6 as a processing gas 22. The gas sensor 7 detects the carbon monoxide concentration, the carbon dioxide concentration, or the ratio between the carbon dioxide concentration and the carbon monoxide concentration (carbon dioxide concentration / carbon monoxide concentration). Hereinafter, the second embodiment will be described more specifically.

(Example 2)
2, the same conditions as in the first embodiment, that is, the ozone decomposition catalyst (75 × 75 × 50 mmt), the catalyst temperature 50 ° C., the gas flow rate 20 slm, the linear velocity 6 cm / s, the residence time 0 .3 seconds, the concentration of water contained in the gas to be treated was controlled under the conditions of a toluene concentration of 100 ppm and an ozone concentration of 1000 ppm, and the by-products generated after the decomposition of toluene were examined.

When the carbon monoxide concentration and the carbon dioxide concentration detected by the gas sensor 7 or the carbon dioxide concentration / carbon monoxide concentration are not in the range of the preset value, for example, the carbon dioxide concentration / carbon monoxide concentration = 3. In this case, it is meant from FIG. 3 that the absolute humidity is about 5 g / m ³ or less. In that case, a signal is sent from the gas sensor 7 to the moisture regulator 2 in order to increase the moisture concentration of the gas 1 to be treated. Carbon dioxide concentration / carbon monoxide moisture controller 2 a water concentration of the gas to be treated in 1 to about 5 to 20 g / ^{m 3} by, from the processing chamber 6 by more preferably controlled to about 8~15g / ^{m 3} Promotes oxidation of discharged gas to carbon dioxide.

On the other hand, for example, when carbon dioxide concentration / carbon monoxide concentration = 7, it means that the absolute humidity is about 15 g / cm ³ or more from FIG. As shown in FIG. 3, the toluene decomposition rate tends to decrease as the moisture concentration (absolute humidity) of the gas to be processed 1 increases. Since the decomposition efficiency of malodorous components needs to be kept high, in this case, it is necessary to reduce the moisture concentration of the gas 1 to be treated. A signal is sent from the gas sensor 7 to the moisture controller 2 in order to reduce the moisture concentration contained in the gas 1 to be treated. By reducing the ratio of the carbon dioxide concentration and the carbon monoxide concentration to about 6 to 6.5, the moisture concentration of the gas to be treated 1 is controlled to about 5 to 20 g / m ^3, preferably about 8 to 15 g / m ^3. .

  As described above, the concentration of water contained in the gas to be treated 1 is optimally adjusted by the carbon dioxide concentration / carbon monoxide concentration obtained based on the carbon dioxide concentration detected by the gas sensor 7 and the carbon monoxide concentration. can do. As a result, toluene was decomposed with high efficiency, and by-products after decomposition were promoted to carbon dioxide. This example shows an example of decomposing malodorous components using the second embodiment, and the type of gas to be treated 1, catalyst temperature, catalyst type, gas flow rate, linear velocity, residence time, ozone concentration Etc. are not limited to the conditions exemplified above. Even when appropriately controlled based on the contents shown in Example 1, the malodorous component can be completely decomposed into carbon dioxide by detecting the value of carbon dioxide concentration / carbon monoxide concentration. In the above method, it is possible to provide a gas decomposition treatment apparatus that decomposes and purifies highly efficient VOC by using an inexpensive gas sensor 7 without using an expensive moisture detector.

Embodiment 3 FIG.
FIG. 4 is a block diagram schematically showing a gas decomposition treatment apparatus according to Embodiment 3 of the present invention. In FIG. 4, the gas sensor 7 has a function of detecting the carbon monoxide concentration, the carbon dioxide concentration, and the total hydrocarbon concentration, and monitors the total number of carbon atoms contained in the processing gas in the subsequent stage of the ozone decomposition catalyst 5. Thus, the total number of carbon atoms of the malodorous component contained in the gas to be treated 1 can be estimated. Reference numeral 8 denotes an ozone controller that controls the amount of ozone generated by the ozone generator 3 according to the detection result of the gas sensor 7. Since other configurations are the same as those of the first embodiment, description thereof is omitted.

In order to decompose the malodorous component contained in the gas 1 to be treated with high efficiency, it is desirable to introduce high-concentration ozone. However, using high-concentration ozone increases the equipment cost. Further, ozone may leak to the subsequent stage of the ozone decomposition catalyst 5.
The gas to be treated 1 containing malodorous components is supplied from the ozone generator 3 after the moisture controller 2 controls the moisture concentration to about 5 to 20 g / m ³ , more preferably about 8 to 15 g / m ^3. And is introduced into an ozone decomposition catalyst 5 provided in the processing chamber 6. The malodorous component is adsorbed and concentrated on the ozone decomposition catalyst 5. In addition, ozone is decomposed into oxygen atoms and oxygen molecules by the ozone decomposition catalyst 5, and oxygen atoms diffuse on the catalyst and oxygen molecules diffuse into the gas phase. Since oxygen atoms have stronger oxidizing power than ozone, they decompose malodorous components adsorbed on the ozone decomposition catalyst 5. By-products after the decomposition of toluene are detected by the gas sensor 7 and a signal is sent to the ozone controller 8 for the total number of detected carbon atoms, and the amount of ozone generated by the ozone generator 3 is controlled. Hereinafter, the third embodiment will be described more specifically with respect to the third embodiment.

(Example 3)
In Example 3, the same ozone decomposition catalyst as in Embodiment 1 (75 × 75 × 50 mmt), catalyst temperature 50 ° C., gas flow rate 33 slm, linear velocity 6 cm / s, residence time 0.5 seconds, toluene concentration 100 ppm Below, the ozone concentration contained in the to-be-processed gas 1 was controlled, and the toluene decomposition rate was investigated. As a result, the ozone concentration to be added should be about 1 to 3 times, more preferably about 1.5 to 2.5 times the number of carbon atoms contained in the malodorous component. The reason is shown below.

FIG. 5 is a characteristic diagram showing the relationship between the ozone concentration measured by the gas decomposition apparatus according to Embodiment 3 shown in FIG. 4 / the toluene decomposition rate with respect to the number of carbon atoms contained in toluene, and the leaked ozone concentration. The decomposition efficiency of toluene is increased by introducing ozone concentration higher than the number of carbon atoms contained in toluene. By controlling the input amount so that the ozone concentration is about 1 to 3 times, more preferably about 1.5 to 2.5 times the number of carbon atoms, toluene can be decomposed with high efficiency.
The same malodorous components other than toluene were examined in the same manner, but in any case, the ozone concentration was increased by about 1.5 to 2.5 times the number of carbon atoms contained in the malodorous component, so that it was highly efficient. The malodorous component can be decomposed, and ozone contributes effectively to the reaction of decomposing the malodorous component, so that ozone leaking from the subsequent stage of the ozone decomposition catalyst 5 can be reduced.

On the other hand, when the ozone concentration is one time or less than the number of carbon atoms, the decomposition efficiency of toluene shows a low value. Moreover, when the ozone concentration is about 3 times or more than the number of carbon atoms, the toluene decomposition rate shows a high value, but since ozone is excessively added to the malodorous component, the ozone concentration leaking from the latter stage of the catalyst is To increase. Further, since the ozone concentration is high, the device cost is increased. Therefore, it is desirable that the input amount of ozone with respect to the number of carbon atoms contained in the gas to be treated is within the above range.
In the case where the initial toluene concentration is a low value, the probability of colliding with oxygen atoms on the catalyst tends to decrease, and the decomposition efficiency tends to decrease. However, by introducing an ozone concentration of about 1 to 3 times, more preferably about 1.5 to 2.5 times the number of carbon atoms, toluene could be decomposed with high efficiency regardless of the toluene concentration. .

  Thus, in this Example 3, the total number of carbon atoms contained in the process gas 22 is monitored using the gas sensor 7 and is included in the gas to be treated 1 in the ozone generator 3 by the ozone controller 8 according to the result. By controlling the ozone concentration to be added to the malodorous component to be about 1 to 3 times, more preferably about 1.5 to 2.5 times the number of carbon atoms contained in the malodorous component, Even if the concentration of the malodorous component contained in the gas to be treated 1 changes over time, the malodorous component can be decomposed with high efficiency, and ozone contributes effectively to the reaction of decomposing the malodorous component. The ozone leaking from the subsequent stage of the catalyst 5 could be reduced.

As described above, according to the third embodiment, the moisture concentration of the gas to be processed 1 is about 5 to 20 g / m ³ , more preferably about 8 to 15 g / m in the moisture controller 2 as in the first embodiment. ^By controlling to ³ , by-products after decomposition do not contain harmful components, and malodorous components can be completely decomposed into carbon dioxide. The total number of carbon atoms is detected by the gas sensor 7, and the ozone concentration is about 1 to 3 times, more preferably about 1.5 to 2.5 times the number of carbon atoms contained in the malodorous component. By controlling the ozone generator 3 with the controller 8, the malodorous component can be decomposed with high efficiency, and ozone leaking from the ozone decomposition catalyst can be reduced.

Embodiment 4 FIG.
FIG. 6 is a diagram showing a configuration of a gas purification apparatus as a gas decomposition processing apparatus according to Embodiment 4 of the present invention. In the figure, 9 is a concentration change mitigating means composed of zeolite having the ability to adsorb malodorous components contained in the gas 1 to be treated, and is provided in the preceding stage of the moisture regulator 2. Since other configurations are the same as those of the third embodiment, description thereof is omitted.

  In the gas decomposition treatment apparatus, the concentration of malodorous components contained in the gas to be treated 1 may change over time. For this reason, for example, when a high-concentration malodorous component is instantaneously included in the gas 1 to be treated, the carbon monoxide concentration, the carbon dioxide concentration, or the carbon dioxide concentration / carbon monoxide concentration, total carbon detected by the gas sensor 7. The number of atoms is different from the concentration of malodorous components contained in the gas to be treated before being processed by the moisture controller 2 or the total number of carbon atoms due to the time difference. For this reason, since the ozone concentration thrown into the malodorous component may be insufficient with respect to the number of carbon atoms, the decomposition efficiency of the malodorous component may be reduced. In this Embodiment 4, in order to cope with such a case, the concentration change mitigation means 9 is installed in the front stage of the moisture regulator 2 in order to prevent the ozone concentration from being insufficient with respect to the number of carbon atoms of the malodorous component. Hereinafter, the fourth embodiment will be described in more detail.

Example 4
The gas to be treated 1 containing a malodorous component passes through a concentration change mitigating means 9 having the ability to adsorb the malodorous component. When the malodorous component rapidly increases, the concentration change mitigating means 9 using zeolite removes the malodorous component. The concentration of the malodorous component is lowered by adsorption, and when the malodorous component is reduced, the malodorous component adsorbed by the concentration change mitigating means 9 is desorbed into the gas to be treated, and the concentration of the malodorous component is increased. The concentration can be adjusted. The to-be-processed gas 1 in which the concentration of the malodorous component is stabilized by the concentration change mitigation means 9 has a water concentration of about 5 to 20 g / m ³ , more preferably about After being controlled to 8 to 15 g / m ³ , it is mixed with ozone fed from the ozone generator 3 and introduced into the ozone decomposition catalyst 5 provided in the processing chamber 6, which is exactly the same as in the third embodiment. Malodorous components are decomposed under conditions and processes.

  In addition, although the case where a zeolite was used was illustrated as the said concentration change mitigation means 9, it is not limited to this, As it can be preferably used similarly, it has the capability to adsorb a malodorous component, for example, silica gel, alumina And so on. In addition, when it is considered that the gas 1 to be treated contains moisture, a hydrophobic zeolite having a small influence of moisture can be desirably used. The volume is determined by the flow rate of the gas 1 to be processed. By using the concentration change mitigation means 9, it is possible to prevent instantaneous high-concentration malodorous components from entering the ozone decomposition catalyst 5, and to prevent a situation in which the ozone concentration to be input is insufficient. As a result, a high decomposition rate can be stably maintained. The above-described example shows an example of decomposing malodorous components using the fourth embodiment. The type of the gas 1 to be treated, the catalyst temperature, the catalyst type, the gas flow rate, the linear velocity, the residence time, etc. The conditions are not limited to the exemplified conditions.

  As described above, according to the fourth embodiment, the concentration of the malodorous component concentration mitigating means 9 is disposed in the upstream of the moisture controller 2, so that the concentration of the malodorous component in the gas to be treated 1 increases instantaneously. Even if the concentration change mitigating means 9 adsorbs the malodorous component, the instantaneous increase of the malodorous component is alleviated at the time when the concentration change mitigating means 9 flows into the moisture regulator 2, and the ozone concentration introduced into the ozone decomposition catalyst 5 is reduced. Can prevent the situation of shortage. For this reason, the effect that the decomposition | disassembly efficiency of a malodorous component is maintained high and it can drive | operate stably is acquired.

Embodiment 5 FIG.
FIG. 7 is a block diagram schematically showing a gas decomposition treatment apparatus according to Embodiment 5 of the present invention. In the figure, 10 is a moisture sensor provided between the moisture regulator 2 and the processing chamber 5 and detects moisture in the gas to be treated, and 11 controls the moisture regulator 2 based on the output signal of the moisture sensor 10. Moisture controller. Since other configurations are the same as those of the third embodiment, description thereof is omitted.

The moisture controller 11 is controlled so that the moisture concentration contained in the gas 1 to be treated is about 5 to 20 g / m ³ , more preferably about 8 to 15 g / m ³ according to the detection result of the moisture sensor 10. To do. The gas 1 to be treated whose water concentration is controlled within the preferable range is mixed with ozone fed from the ozone generator 3 and introduced into the ozone decomposition catalyst 5. The malodorous component is adsorbed and concentrated on the ozone decomposition catalyst 5. In addition, ozone is decomposed into oxygen atoms and oxygen molecules by the ozone decomposition catalyst 5, and oxygen atoms diffuse on the catalyst and oxygen molecules diffuse into the gas phase. Since oxygen atoms have stronger oxidizing power than ozone, they decompose malodorous components adsorbed on the ozone decomposition catalyst 5. The gas sensor 7 detects the carbon monoxide concentration, carbon dioxide concentration, carbon dioxide concentration / carbon monoxide concentration, and total hydrocarbon concentration generated after decomposition of the malodorous component, and sends a signal to the ozone controller 8. The ozone controller 8 that has received a signal from the gas sensor 7 controls the amount of ozone generated by the ozone generator 3 in accordance with the total number of carbon atoms contained in the gas downstream of the catalyst. Example 5 will be described below.

(Example 5)
For example, the moisture concentration of the gas to be treated 1 containing a malodorous component is detected by the moisture sensor 10. If the moisture concentration is not in the range of about 5-20 g / m ³ , the moisture sensor 10 sends a signal to the moisture controller 11. Upon receiving the signal, the moisture controller 11 controls the moisture regulator 2 so that the moisture concentration contained in the gas to be treated 1 is about 5 to 20 g / m ³ , more preferably about 8 to 15 g / m ^3. Control. After the moisture concentration contained in the gas to be treated 1 is controlled by the moisture regulator 2, the odor components are decomposed with high efficiency by decomposing with the ozone decomposition catalyst 5 in the same manner as in the third embodiment. The product can be completely decomposed to carbon dioxide. Further, the ozone concentration to be input is desirably about 1 to 3 times, more preferably about 1.5 to 2.5 times the number of carbon atoms of the malodorous component contained in the gas 1 to be treated.

As described above, according to the fifth embodiment, the moisture concentration of the gas 1 to be processed is set to about 5 to 20 g / m by the moisture controller 11 according to the detection result of the moisture sensor 10 provided at the subsequent stage of the moisture controller 2. ³ , More preferably, by controlling to about 8 to 15 g / m ³ , the by-product after decomposition does not contain harmful components and can completely decompose malodorous components into carbon dioxide. Further, the malodorous component can be decomposed with high efficiency by detecting the total number of carbon atoms by the gas sensor 7 and controlling the amount of ozone generated by the ozone controller 8 according to the result.

Embodiment 6 FIG.
FIG. 8 is a block diagram schematically showing a gas decomposition treatment apparatus according to Embodiment 6 of the present invention. In FIG. 8, an ozone decomposition catalyst 5 that adsorbs and decomposes malodorous components using ozone is disposed in a processing chamber 6 that performs decomposition processing of malodorous components contained in the gas 1 to be processed. The two-stage catalyst layer 52 and the third-stage catalyst layer 53 are provided in three stages in series in the gas flow direction, and the ozone generated by the ozone generator 3 is converted into the catalyst of each stage of the ozone decomposition catalyst 5. Each of the layers 51, 52, 53 is configured to be fed separately from the front. Since other configurations are the same as those of the third embodiment, description thereof is omitted.

The to-be-processed gas 1 containing a malodorous component is controlled by the moisture controller 2 to a moisture concentration of about 5 to 20 g / m ³ , more preferably about 8 to 15 g / m ³ . The gas 1 to be processed whose moisture concentration is controlled is mixed with ozone generated from the ozone generator 3 and introduced into the first stage catalyst layer 51 provided in the processing chamber 6. The malodorous component is adsorbed and concentrated on the first stage catalyst layer 51. Further, ozone is decomposed into oxygen atoms and oxygen molecules by the first stage catalyst layer 51, oxygen atoms diffuse on the catalyst, and oxygen molecules diffuse into the gas phase. Oxygen atoms have a stronger oxidizing power than ozone, and thus decompose malodorous components adsorbed on the first stage catalyst layer 51. The malodorous component leaking from the first stage catalyst layer 51 is mixed with ozone having the same concentration as the ozone contained in the first stage catalyst layer 51 fed from the ozone generator 3 in front of the second stage catalyst layer 52. The The mixed gas is introduced into the second stage catalyst layer 52, and the leaked malodorous component is decomposed in the same manner as the first stage catalyst layer 51.

  Similarly, the same decomposition treatment is performed in the third stage catalyst layer 53. As a result, malodorous components can be decomposed with high efficiency. The decomposed malodorous component is discharged from the processing chamber 6. The carbon sensor concentration, carbon dioxide concentration or carbon dioxide concentration / carbon monoxide concentration ratio, and total hydrocarbon concentration produced after decomposition of the malodorous component are detected by the gas sensor 7, and a signal is sent to the ozone controller 8. The ozone controller 8 that has received the signal from the gas sensor 7 controls the amount of ozone generated by the ozone generator 3 according to the total number of carbon atoms. Hereinafter, Example 6 will be described more specifically.

(Example 6)
The ozone decomposition catalyst 5 is divided into a first stage catalyst layer 51, a second stage catalyst layer 52, and a third stage catalyst layer 53 in the flow direction of the gas 1 to be treated, and divided into three stages. Ozone is introduced from the front part of the layer. For example, malodorous components introduced into the first stage first catalyst layer 51 are decomposed on the first stage catalyst layer 51 by introducing ozone. The malodorous component leaked without being decomposed in the first stage catalyst layer 51 is adsorbed by the second stage catalyst layer 52 of the second stage.

  Since the concentration of the malodorous component leaked from the first stage catalyst layer 51 is lower than the concentration of the malodorous component contained in the gas 1 to be treated, the ozone concentration introduced into the first stage catalyst layer 51 in the second stage catalyst layer 52 and By introducing the same concentration, malodorous components can be efficiently decomposed. Further, when the malodorous component remains, the malodorous component is decomposed by the third-stage catalyst layer 53 of the third step. In this embodiment, the decomposition efficiency of the malodorous component can be improved by about 20 to 50%. The division of the ozone decomposition catalyst 5 is not limited to three stages, and may be, for example, two stages or four stages or more. Further, the ozone gas flow rate and ozone concentration to be input may be appropriately divided at a predetermined ratio.

In the ozone decomposition catalyst 5, the malodorous component is decomposed and simultaneously the self-decomposition of ozone proceeds. As a result of the study and implementation of the present inventors, it was found that the self-decomposition of ozone is faster than the decomposition reaction of malodorous components. By dividing the ozone decomposition catalyst 5 into a plurality as in this embodiment, invalid consumption of ozone due to self-decomposition can be suppressed.
As described above, according to the sixth embodiment, in addition to the effects of the third embodiment, the ozone decomposition catalyst that adsorbs and decomposes malodorous components is divided into a plurality of stages in the gas flow direction. The decomposition efficiency of components can be further increased.

Embodiment 7 FIG.
FIG. 9 is a block diagram schematically showing a gas decomposition treatment apparatus according to Embodiment 7 of the present invention. In FIG. 9, reference numeral 12 denotes ozone leakage prevention means for completely removing ozone leaking into the processing gas 22 from the subsequent stage of the ozone decomposition catalyst 5, and is made of, for example, activated carbon. Since other configurations are the same as those of the third embodiment, description thereof is omitted.

After the gas to be treated 1 containing malodorous components moisture regulator 2 water concentration at about 5 to 20 g / ^{m 3,} which is more preferably controlled to about 8~15g / ^{m 3,} the ozone generated from the ozone generator 3 And introduced into the ozone decomposition catalyst 5 provided in the processing chamber 6. The malodorous component is adsorbed and concentrated on the ozone decomposition catalyst 5. In addition, ozone is decomposed into oxygen atoms and oxygen molecules by the ozone decomposition catalyst 5, and oxygen atoms diffuse on the catalyst and oxygen molecules diffuse into the gas phase. Oxygen atoms have a stronger oxidizing power than ozone, so that malodorous components adsorbed on the ozone decomposition catalyst 5 are decomposed. All hydrocarbons contained in the treated gas 22 after decomposition are detected by the gas sensor 7 and a signal is sent to the ozone controller 8. The ozone controller 8 that has received the signal from the gas sensor 7 controls the amount of ozone generated by the ozone generator 3 according to the total number of carbon atoms. The gas 1 to be processed discharged from the processing chamber 6 passes through the ozone leakage preventing means 12 and is completely discharged and then released to the outside. Hereinafter, Example 7 will be described more specifically.

(Example 7)
If the gas to be treated 1 contains moisture, the ozone decomposition catalyst 5 is poisoned, and undecomposed ozone that lowers the ozone decomposition ability may be discharged to the outside. However, in Example 7, even if ozone leaks after the ozone decomposition catalyst 5, ozone is decomposed by the ozone leakage prevention means 12 and is not discharged to the outside air. The ozone leakage prevention means 12 can be used without any particular limitation as long as it is a catalyst having a function of decomposing ozone, but a catalyst containing activated carbon which is advantageous in terms of cost is desirable. Further, as the catalyst carrier, for example, incombustible solid such as Al ₂ O ₃ , SiO ₂ , Al (OH) ₃ can be desirably used.

According to the seventh embodiment configured as described above, the moisture control the water concentration of the gas to be treated 1 2 to about 5 to 20 g / ^{m 3,} more preferably be controlled to about 8~15g / ^{m 3} Therefore, the by-product after decomposition does not contain harmful components, and the malodorous components can be completely decomposed into carbon dioxide. In addition, the total number of carbon atoms can be detected by the gas sensor 7 to control the amount of ozone generated. The amount of ozone generated is about 1 to 3 times, more preferably about 1.5 to 2.5 times the number of carbon atoms contained in the malodorous component, so that the malodorous component can be decomposed with high efficiency. I can do it. Further, since the ozone leakage prevention means 12 is installed at the subsequent stage of the gas sensor 7, ozone can be completely decomposed and leakage ozone can be reduced. Moreover, when the ozone leak prevention means 12 uses activated carbon or a catalyst containing activated carbon, the cost can be reduced.

Embodiment 8 FIG.
FIG. 10 is a block diagram schematically showing a gas decomposition processing apparatus according to Embodiment 8 of the present invention. In FIG. 10, 13 is a carbon monoxide oxidizing means for oxidizing carbon monoxide generated as a by-product after decomposition of malodorous components by the ozone decomposition catalyst 5. The present inventors have found that carbon monoxide is generated after decomposition of malodorous components in an apparatus for decomposing malodorous components using an ozone decomposition catalyst, and have completed the invention of Embodiment 8. . Since carbon monoxide is harmful, emissions need to be reduced. Hereinafter, the eighth embodiment will be described more specifically with reference to the eighth embodiment.

(Example 8)
As the carbon monoxide oxidizing means 13, a noble metal catalyst and an ultraviolet lamp are used. The gas containing carbon monoxide is oxidized to carbon dioxide by a noble metal catalyst. Pt and Ru are desirable as the noble metal catalyst for oxidizing carbon monoxide. In addition, by installing an ultraviolet lamp, OH radicals are generated and carbon monoxide is oxidized to carbon dioxide.

  The gas to be treated 1 containing a malodorous component is mixed with ozone generated from the ozone generator 3. The gas 1 to be processed is introduced into an ozone decomposition catalyst 5 provided in the processing chamber 6, and the gas to be processed such as malodorous components is adsorbed and concentrated on the ozone decomposition catalyst 5. In addition, ozone is decomposed into oxygen atoms and oxygen molecules by the ozone decomposition catalyst 5, and oxygen atoms diffuse on the catalyst and oxygen molecules diffuse into the gas phase. Since oxygen atoms have stronger oxidizing power than ozone, they decompose malodorous components adsorbed on the ozone decomposition catalyst 5. The processing gas processed in the processing chamber 6 is oxidized to carbon dioxide by the carbon monoxide oxidizing means 13. For this reason, a malodorous component can be oxidatively decomposed into carbon dioxide.

As described above, according to the eighth embodiment of the present invention, by installing the carbon monoxide oxidizing means 13 at the subsequent stage of the processing chamber 6, the carbon monoxide generated after the decomposition of the malodorous component is oxidized to carbon dioxide. Thus, a gas decomposition treatment apparatus that prevents leakage of carbon monoxide to the outside air can be obtained. Further, in this embodiment, a moisture regulator is not necessary.
Note that, for example, the carbon monoxide oxidizing means 13 may be installed downstream of the processing chamber 6 in the configuration of the first to seventh embodiments. In this case, even if carbon monoxide leaks from the processing chamber 6 for some reason, it can be reliably oxidatively decomposed into carbon dioxide, so that the reliability of the apparatus can be improved.

  By the way, the type of component gas to be processed such as VOC exemplified in each embodiment, the type of catalyst such as an ozone decomposition catalyst, the temperature of the catalyst, the gas flow rate of the gas to be processed, the linear velocity, the residence time, or the type of sensor, These are merely examples, and are not limited to these. It is also possible to combine two or more configurations of the illustrated embodiments, and in that case, a synergistic effect can be expected.

The block diagram which shows typically the gas decomposition processing apparatus by Embodiment 1 of this invention. The block diagram which shows typically the gas decomposition processing apparatus by Embodiment 2 of this invention. The relationship between toluene decomposition rate with respect to absolute humidity and carbon dioxide concentration / carbon monoxide concentration (CO ₂ concentration / CO concentration) of the gas to be treated containing toluene obtained by an experiment using the apparatus shown in FIG. 1 or FIG. FIG. The block diagram which shows typically the gas decomposition processing apparatus by Embodiment 3 of this invention. It is a characteristic view which shows the relationship between the ozone concentration measured by the gas decomposition treatment apparatus according to Embodiment 3 shown in FIG. 4 / the toluene decomposition rate with respect to the number of carbon atoms contained in toluene, and the leaked ozone concentration. The block diagram which shows typically the gas decomposition processing apparatus by Embodiment 4 of this invention. The block diagram which shows typically the gas decomposition processing apparatus by Embodiment 5 of this invention. The block diagram which shows typically the gas decomposition processing apparatus by Embodiment 6 of this invention. The block diagram which shows typically the gas decomposition processing apparatus by Embodiment 7 of this invention. The block diagram which shows typically the gas decomposition treatment apparatus by Embodiment 8 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Gas to be processed, 2 Moisture controller, 3 Ozone generator, 4 Raw material gas, 5 Ozone decomposition catalyst, 6 Processing chamber, 7 Gas sensor, 8 Ozone controller, 9 Concentration change mitigation means, 10 Moisture sensor, 11 Moisture controller , 12 ozone leakage prevention means, 13 carbon monoxide oxidation means, 21 flow path, 22 process gas, 51 first stage catalyst layer, 52 first stage catalyst layer, 53 third stage catalyst layer.

Claims (5)

In a gas decomposition treatment apparatus that decomposes a component gas contained in a treatment gas using ozone and an ozone decomposition catalyst, moisture adjustment for controlling a moisture concentration contained in the treatment gas before the ozone decomposition catalyst And a gas sensor that can detect carbon monoxide and carbon dioxide, which is provided after the ozonolysis catalyst, and the moisture regulator is included in the gas to be treated according to the detection result of the gas sensor. features and to Ruga scan cracking facility that controls the water. In a gas decomposition treatment apparatus that decomposes a component gas contained in a treatment gas using ozone and an ozone decomposition catalyst, moisture adjustment for controlling a moisture concentration contained in the treatment gas before the ozone decomposition catalyst A gas sensor that is provided downstream of the ozonolysis catalyst and that can detect all carbon, and according to the detection result of the gas sensor, 1 of ozone required for decomposition with respect to the carbon number of the component gas to be treated 3 times characteristics and be Ruga scan decomposition treating apparatus by comprising a ozone controller which controls the ozone input amount to a concentration of. The moisture regulator, gas decomposition processor according to claim 1 or claim 2, characterized in that to control the water concentration contained in the gas to be treated 5 to 20 g / m ^3. 3. The gas decomposition treatment apparatus according to claim 1, further comprising concentration change mitigation means for mitigating a concentration change of the component gas to be treated contained in the gas to be treated. The ozone decomposition catalyst, the addition to the installation is divided into multiple stages in flow direction of the gas to be treated, according to claim 1 or claim characterized by comprising as to inject ozone for each ozone decomposition catalyst in each stage Item 3. The gas decomposition treatment apparatus according to Item 2 .

Images