JP2005199123A - Exhaust gas treatment method for gas sterilizer and apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust gas treatment apparatus capable of safely and efficiently detoxifying high concentration of sterilization gas. <P>SOLUTION: The exhaust gas treatment apparatus for a gas sterilizer for detoxifying the exhaust gas from the gas sterilizer 2 is provided with an adsorption column 5 for adsorbing the sterilization gas in the exhaust gas; a catalyst burning device 6 for catalyst-burning the sterilization gas in the exhaust gas discharged from the adsorption column 5; an ejector 11 for introducing diluted air previously heated by a previous heating heater 13 when the exhaust gas discharged from the adsorption column 5 is introduced to the catalyst burning device 6; and a heat exchanger 4 for heat-exchanging the exhaust gas discharged from the catalyst burning device 6 and the exhaust gas diluted in the ejector 11 and introduced to the catalyst burning device 6 and previously heating the exhaust gas introduced to the catalyst burning device 6. Exact detoxification is carried out and safety can be ensured while saving the amount of heating in the previous heating heater 13, enhancing energy efficiency and outstandingly reducing a running cost. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a gas sterilizer for sterilizing articles to be sterilized such as clothes, bedding, and medical equipment materials using a sterilizing gas such as ethylene oxide, to detoxify and discharge harmful sterilizing gas after the sterilization process is completed. The present invention relates to an exhaust gas treatment method and apparatus for a gas sterilizer.

  Medical sterilizers include a steam sterilizer using steam and a gas sterilizer using a sterilization gas such as ethylene oxide.

  The gas sterilizer includes a positive pressure type sterilizer that holds the inside of the sterilization tank at a slightly higher positive pressure than the atmospheric pressure and performs sterilization with about 10 to 30% ethylene oxide gas, and a sterilization tank. There is a negative pressure type sterilizer that maintains a negative pressure slightly lower than the atmospheric pressure and sterilizes with 100% concentration ethylene oxide gas.

  The ethylene oxide gas used in the gas sterilizer is harmful to the human body and explosive, so it must be handled with care. However, in the positive pressure type sterilizer, sterilization in the sterilization tank is necessary. Recently, negative pressure type sterilizers are becoming mainstream from the viewpoint of safety because gas may leak to the outside and contaminate the surroundings.

  Further, in the above gas sterilizer, it is necessary to completely discharge the sterilization gas in the tank for the safety of the operator when taking out the object to be sterilized in the sterilization tank after completion of sterilization. And in discharging | emitting sterilization gas, it is necessary to collect | recover sterilization gas completely or to make it harmless.

  As a method for treating such a sterilizing gas, there are a method in which ethylene oxide gas is dissolved in water to treat it as ethylene glycol, and a method in which a combustion furnace is installed outdoors and burned.

  However, the former method requires a large apparatus such as a scrubber in order to sufficiently dissolve the ethylene oxide gas in water, which is uneconomical in terms of equipment. In the latter method, a combustion apparatus for burning ethylene oxide is required, and the apparatus becomes complicated and large in size, which is uneconomical in terms of equipment, and also requires fuel for burning ethylene oxide. It is uneconomical in terms of cost.

  Therefore, a sterilization gas processing apparatus disclosed in Patent Document 1 below has been devised as a sterilization gas processing apparatus that can decompose sterilization gas with a relatively simple configuration and has a low running cost.

The apparatus includes an adsorption tower that adsorbs ethylene oxide gas in exhaust gas, and a catalytic combustion apparatus that is connected in series with the adsorption tower and burns residual ethylene oxide gas in the exhaust gas that has passed through the adsorption tower. Yes. In this apparatus, the sterilizing gas discharged from the sterilizer is adsorbed by the adsorption tower, and then the residual ethylene oxide gas is burned by the catalytic combustion apparatus to make it harmless. In addition, the ethylene oxide gas adsorbed in the adsorption tower is desorbed with aeration gas from a sterilizer, and the desorbed gas is burned with a catalytic combustion device to be rendered harmless.
JP-A-8-215541

  However, in the sterilization gas processing apparatus, the sterilization gas discharged from the sterilizer is directly passed through the adsorption tower and the catalytic combustion apparatus, and the sterilization gas adsorbed in the adsorption tower is desorbed with the aeration gas. For this reason, it is suitable for detoxification of sterilization gas having an ethylene oxide gas concentration of about 10 to 30%, but when applied to sterilization gas having an ethylene oxide gas concentration of 100%, high concentration ethylene oxide gas exceeding the explosion limit is treated. There is a risk of passing through the apparatus and being introduced into the catalytic combustion apparatus. Therefore, although the sterilization gas treatment apparatus can be used for a positive pressure sterilizer having a relatively low ethylene oxide gas concentration, it is not suitable for a negative pressure sterilizer using a high concentration ethylene oxide gas as a sterilization gas. Could not be used.

  Further, in the sterilization gas processing apparatus, since the sterilization gas adsorbed by the adsorption tower is desorbed with an aeration gas containing some amount of ethylene oxide gas, it is difficult to completely desorb and promote desorption. It is necessary to provide heating means in the adsorption tower. When desorbing while heating the adsorption tower using activated carbon as the adsorbent, if the heating temperature is about 160 degrees, there is a possibility of ignition and combustion, which is not preferable in terms of safety.

  The present invention has been made in view of such circumstances, and an object thereof is to provide an exhaust gas treatment method and apparatus for a gas sterilizer capable of detoxifying a high-concentration sterilization gas safely and efficiently.

  In order to achieve the above object, a first exhaust gas treatment method for a gas sterilizer according to the present invention is an exhaust gas treatment method for a gas sterilizer that renders exhaust gas from the gas sterilizer harmless, and adsorbs sterilization gas in the exhaust gas. A catalytic combustion process for catalytically burning sterilized gas in the exhaust gas discharged from the adsorption process, and a first dilution process for introducing dilution air when introducing the exhaust gas discharged from the adsorption process into the catalytic combustion process A preheating step for preheating the diluted air or a mixed gas of exhaust gas and diluted air, an exhaust gas discharged from the catalytic combustion step, and an exhaust gas diluted in the first dilution step and introduced into the catalytic combustion step. And a heat exchange step for further preheating the exhaust gas that is exchanged and introduced into the catalytic combustion step.

  Further, the second exhaust gas treatment method for a gas sterilizer of the present invention is an exhaust gas treatment method for a gas sterilizer for detoxifying exhaust gas from the gas sterilizer, the adsorption step for adsorbing sterilization gas in the exhaust gas, and the adsorption A catalytic combustion process for catalytically burning sterilized gas in the exhaust gas discharged from the process; a first dilution process for introducing diluted air when introducing the exhaust gas discharged from the adsorption process into the catalytic combustion process; and the diluted air Alternatively, the present invention includes a preheating step of preheating a mixed gas of exhaust gas and diluted air with a preheater in advance.

  An exhaust gas treatment apparatus for a first gas sterilizer according to the present invention is an exhaust gas treatment apparatus for a gas sterilizer that renders exhaust gas from a gas sterilizer harmless, and includes an adsorption tower that adsorbs sterilization gas in the exhaust gas, and the adsorption tower. A catalytic combustion device for catalytic combustion of sterilized gas in the exhaust gas discharged; a first dilution means for introducing dilution air when introducing the exhaust gas discharged from the adsorption tower into the catalytic combustion device; and the diluted air or exhaust gas A preheating heater that preheats a mixed gas of air and diluted air, and exhaust gas discharged from the catalytic combustion device and exhaust gas that is diluted by the first dilution means and introduced into the catalytic combustion device to exchange heat. The gist of the invention is that it includes a heat exchanger for further preheating the introduced exhaust gas.

  A second exhaust gas treatment apparatus for a gas sterilizer according to the present invention is an exhaust gas treatment apparatus for a gas sterilizer that renders exhaust gas from a gas sterilizer harmless, and includes an adsorption tower that adsorbs sterilization gas in the exhaust gas, and the adsorption tower. A catalytic combustion device for catalytic combustion of sterilized gas in the exhaust gas discharged; a first dilution means for introducing dilution air when introducing the exhaust gas discharged from the adsorption tower into the catalytic combustion device; and the diluted air or exhaust gas The gist of the present invention is that it includes a preheating heater that preheats a mixed gas of the air and dilution air.

  In the first exhaust gas treatment method and apparatus for a gas sterilizer according to the present invention, dilution air is introduced when the exhaust gas discharged from the adsorption tower is introduced into the catalytic combustion apparatus, and the dilution air or the mixture of the exhaust gas and the dilution air is introduced. Preheat the gas. In this way, after sterilizing gas such as ethylene oxide gas is adsorbed in the adsorption step or adsorption tower, the exhaust gas is further diluted with diluted air and introduced into the catalytic combustion step or device, so that it flows through the catalytic combustion step or device. Since the concentration of sterilization gas is greatly reduced, there is almost no risk of ignition or explosion. In addition, since the diluted air or a mixed gas of diluted air and exhaust gas is preheated, the temperature reduction of the catalytic combustion process or the apparatus due to the introduction of the diluted air can be prevented, and the occurrence of an abatement failure accident due to insufficient combustion. It can be prevented in advance and ensured safety by ensuring detoxification. Furthermore, the exhaust gas discharged from the catalytic combustion process or device and the exhaust gas diluted and introduced into the catalytic combustion process or device are heat-exchanged to further preheat the exhaust gas introduced into the catalytic combustion process or device. The amount of heating in the heater can be saved, energy efficiency can be improved, and running costs can be greatly reduced, while ensuring detoxification and ensuring safety.

  In the second exhaust gas treatment method and apparatus for a gas sterilizer according to the present invention, dilution air is introduced when introducing the exhaust gas discharged from the adsorption tower into the catalytic combustion apparatus, and the dilution air or the exhaust gas and the dilution air are introduced. Preheat the mixed gas. In this way, after sterilizing gas such as ethylene oxide gas is adsorbed in the adsorption step or adsorption tower, the exhaust gas is further diluted with diluted air and introduced into the catalytic combustion step or device, so that it flows through the catalytic combustion step or device. Since the concentration of sterilization gas is greatly reduced, there is almost no risk of ignition or explosion. In addition, since the diluted air or a mixed gas of diluted air and exhaust gas is preheated, the temperature reduction of the catalytic combustion process or the apparatus due to the introduction of the diluted air can be prevented, and the occurrence of an abatement failure accident due to insufficient combustion. It can be prevented in advance and ensured safety by ensuring detoxification.

  In the second exhaust gas treatment method for a gas sterilizer according to the present invention, the second dilution step of introducing diluted air to the exhaust gas introduced into the adsorption step, the exhaust gas discharged from the catalyst combustion step, and the first dilution step are diluted. And the second gas sterilizer of the present invention further comprising a heat exchanging step for further preheating the mixed gas introduced into the catalytic combustion step by exchanging heat with the mixed gas introduced into the catalytic combustion step. In the exhaust gas treatment apparatus, the second dilution means for introducing diluted air to the exhaust gas to be introduced into the adsorption tower, the exhaust gas discharged from the catalytic combustion apparatus and the first dilution means are diluted and introduced into the catalytic combustion apparatus. If it is further equipped with a heat exchanger that preheats the mixed gas introduced into the catalytic combustion device by exchanging heat with the mixed gas, the exhaust gas introduced into the adsorption tower or adsorption process is diluted. Since the introduction diluted with air, since the concentration of the sterilizing gas flowing through the exhaust gas treatment system entirely decreased, the risk of ignition and explosion greatly reduced. Since the exhaust gas to be introduced into the adsorption tower or adsorption process is diluted with diluted air and introduced, the concentration of sterilizing gas flowing through the exhaust gas treatment system is reduced overall, further reducing the risk of ignition and explosion, and safety Can be secured. In addition, since the exhaust gas discharged from the catalytic combustion process or apparatus and the mixed gas diluted and introduced into the catalytic combustion process or apparatus are heat-exchanged, the exhaust gas introduced into the catalytic combustion process or apparatus is further preheated, The amount of heating in the preheater can be saved, energy efficiency can be improved, and running costs can be greatly reduced, while ensuring detoxification and ensuring safety.

  In this case, especially when the amount of diluted air introduced is controlled so that the concentration of the sterilizing gas discharged from the adsorption process or adsorption tower is below the explosion limit, the risk of ignition and explosion is almost completely eliminated. it can. In particular, in a negative pressure sterilizer using a high-concentration sterilization gas, it becomes possible to make the exhaust gas harmless safely and efficiently, and the safety of the surrounding environment of the sterilizer can be improved. It goes without saying that a safe and efficient detoxification process can also be performed in a positive pressure sterilizer.

  In this case, when dilution air is constantly introduced into the adsorption step or adsorption tower, the pressure fluctuation of the fluid in the exhaust gas treatment system is reduced and stabilized, and the aging of the apparatus can be prevented to some extent.

  Furthermore, in this case, by constantly introducing dilution air into the adsorption step or adsorption tower, when the exhaust gas from the sterilizer is interrupted, the sterilized gas adsorbed in the adsorption step or adsorption tower is desorbed by the dilution air. In such a case, the diluted air can act as a desorption gas for the adsorption tower to regenerate the adsorbent. That is, for example, after the sterilization gas in the sterilizer is exhausted, the atmosphere is introduced into the sterilizer, and aeration is performed to exhaust the exhaust gas by repeating the vacuum exhaust and the air introduction. And since the introduction of exhaust gas from the sterilizer to the exhaust gas treatment device is interrupted in the air introduction step, the dilution air is constantly introduced into the adsorption step or adsorption tower, so that the dilution air becomes the desorption gas of the adsorption step or adsorption tower. The adsorbed sterilizing gas is desorbed and the adsorbent is regenerated.

  Since desorption is performed with diluted air that does not contain sterilization gas, the desorption efficiency is improved as compared with the conventional method in which desorption is performed with aeration gas, and there is no need to provide heating means in the adsorption step or adsorption tower. Therefore, the danger of ignition and combustion is avoided and the safety is further improved. Further, when dilution air is constantly introduced into the adsorption step or the adsorption tower, the pressure fluctuation of the fluid in the exhaust gas treatment system is reduced and stabilized, and the aging of the apparatus can be prevented to some extent.

  In the exhaust gas treatment method for a gas sterilizer according to the present invention, the first dilution step includes sucking the exhaust gas discharged from the adsorption step by applying a negative pressure by the air flow of the dilution air, and the present In the exhaust gas treatment apparatus for a gas sterilizer according to the invention, when the first diluting means is an ejector that sucks the exhaust gas discharged from the adsorption tower by applying a negative pressure by the air flow of the diluted air, an adsorption step Or, by applying negative pressure to the exhaust gas discharged from the adsorption tower and sucking it, the adsorption process or the adsorption tower is operated in a negative pressure state to prevent the backflow of sterilization gas to the sterilizer or the adsorption process or adsorption. The leakage of sterilization gas from the tower can be prevented, and the safety of the sterilizer and the surrounding environment can be secured. In addition, since negative pressure to the adsorption process or adsorption tower is generated by the air flow of dilution air, no special suction device or valve operation is required, and backflow of sterilization gas due to troubles of those devices does not occur. It becomes a highly safe apparatus and method.

  Next, the best mode for carrying out the present invention will be described.

  FIG. 1 is a diagram showing an exhaust gas treatment apparatus for a gas sterilizer according to an embodiment of the present invention. In the figure, 1 is an exhaust gas treatment apparatus of the present invention, and 2 is a gas sterilizer.

  The gas sterilizer 2 includes an exhaust pump 3 for discharging exhaust gas in a sterilization tank (not shown). The exhaust gas treatment device 1 is connected to the exhaust pipe of the exhaust pump 3 to harm the exhaust gas. Perform processing to convert.

  In this embodiment, the gas sterilizer 2 uses a negative pressure type gas sterilizer 2 that performs sterilization and the like while maintaining the inside of the sterilization tank at atmospheric pressure or lower, and 100% ethylene oxide as a sterilization gas. An example using gas will be described.

  Exhaust gas is exhausted by the exhaust pump 3 as follows. That is, first, the exhaust pump 3 is operated and exhausted from the sealed sterilization tank after the sterilization process is completed, and the exhaust is performed when the inside of the sterilization tank is reduced to a predetermined pressure or less. And introduce air into the sterilization tank. When the atmosphere is introduced until the inside of the sterilization tank is close to the atmospheric pressure, the sterilization tank is again sealed and exhausted by the exhaust pump 3. This operation is called aeration, and exhaust gas in the sterilization tank is discharged by repeating this aeration a predetermined number of times.

  The exhaust gas treatment apparatus 1 includes an adsorption tower 5 that adsorbs sterilization gas in exhaust gas, and a catalytic combustion apparatus 6 that catalytically burns the sterilization gas in exhaust gas discharged from the adsorption tower 5.

  The adsorption tower 5 communicates with the second exhaust gas introduction path 7 branched from the exhaust gas path 17 communicating with the exhaust pump 3 of the gas sterilizer 2. A first valve 18 and a second valve 19 are provided in the exhaust gas passage 17 and the second exhaust gas introduction passage 7, respectively. When the sterilization process in the gas sterilizer 2 is completed, the exhaust pump 3 is operated, and the first valve 18 is closed and the second valve 19 is opened, so that the exhaust gas in the sterilization tank is introduced into the second exhaust gas. It is introduced into the adsorption tower 5 by a path 7. In the drawing, 15 is a pressure gauge provided in the exhaust gas passage 17.

  In the adsorption tower 5, for example, a cylindrical case is filled with an adsorbent, and ethylene oxide which is a sterilized gas component in the exhaust gas introduced into the adsorption tower 5 is adsorbed and removed. As the adsorbent, for example, activated carbon, zeolite, silica gel, activated alumina and the like can be used. In particular, activated carbon can be suitably used because the adsorbed ethylene oxide gas can be desorbed relatively easily. These adsorbents can be used alone or in combination.

  The exhaust port of the adsorption tower 5 and the intake port of the catalytic combustion apparatus 6 are communicated with each other through a first exhaust gas introduction path 9 so that the exhaust gas that has passed through the adsorption tower 5 is introduced into the catalytic combustion apparatus 6. Yes.

  The catalyst combustion device 6 is filled with a catalyst and heated to a predetermined temperature, whereby the ethylene oxide gas in the exhaust gas is decomposed and made harmless by catalytic combustion, and is discharged from the processing gas discharge passage 16. ing.

  As the catalyst used in the catalytic combustion apparatus 6, noble metal catalyst can be suitably used because combustion proceeds at a low temperature and low concentration ethylene oxide gas can be catalytically combusted. As such a noble metal catalyst, for example, platinum, rhodium, palladium or the like can be suitably used, and a catalyst in which these noble metals are supported on an appropriate carrier such as silica, alumina, zeolite or the like can be used.

  The exhaust gas treatment apparatus 1 is provided with a second air introduction path 8 as a second dilution means of the present invention for introducing dilution air into a second exhaust gas introduction path 7 for introducing exhaust gas into the adsorption tower 5. . Further, a first air introduction path 10 for introducing diluted air is provided in a first exhaust gas introduction path 9 for introducing the exhaust gas discharged from the adsorption tower 5 into the catalytic combustion apparatus 6.

  Each of the first air introduction path 10 and the second air introduction path 8 branches from an air supply path that communicates with a blower or a compressor (hereinafter referred to as “blower”) 12 that is an air generating device, and is divided into one blower 12. Dilution air is supplied to the first and second air introduction passages 10 and 8. By doing in this way, since one air generator is sufficient, it is advantageous in terms of equipment cost and maintenance cost.

  The second air introduction path 8 has an orifice 14 for adjusting the flow rate of diluted air for diluting the exhaust gas introduced into the adsorption tower 5, and a check that prevents the exhaust gas from flowing to the blower 12 side and ensures safety. A valve 21 is provided. In this apparatus, the orifice 14 is provided on the upstream side of the second air introduction path 8, and the check valve 21 is provided on the downstream side, so that the dilution air introduced from the second air introduction path 8 can be reduced. The flow rate is more stable and more stable operation can be performed.

  While the exhaust gas treatment apparatus 1 is in operation, dilution air from the blower 12 and the second air introduction path 8 is constantly introduced into the second exhaust gas introduction path 7. By doing in this way, when the exhaust gas from the gas sterilizer 2 is interrupted, such as during air introduction to the sterilization tank in aeration, the diluted air from the second air introduction path 8 flows into the adsorption tower 5, The ethylene oxide gas adsorbed by the adsorbent in the adsorption tower 5 is desorbed by the diluted air. In this case, “always” means “substantially always from the start to the end of exhaust gas treatment”.

  On the other hand, the first air introduction path 10 is provided with a preheating heater 13 that preheats diluted air introduced into the catalytic combustion device 6 to prevent a temperature drop in the catalytic combustion device 6. Note that the preheater 13 may be externally attached to the catalytic combustion apparatus 6 in order to reduce the size of the apparatus, or a type built in the catalytic combustion apparatus 6 may be used. Further, the exhaust gas discharged from the adsorption tower 5 is sucked into the communicating portion between the first air introduction path 10 and the first exhaust gas introduction path 9 by applying a negative pressure to the exhaust gas discharged from the adsorption tower 5 according to the present invention. An ejector 11 is provided as one dilution means.

  For example, as shown in FIG. 2, the ejector 11 has a T-shaped flow path, and the dilution air supplied from the blower 12 flows through the illustrated vertical flow path 23 to the catalytic combustion apparatus 6. The exhaust gas supplied and discharged from the adsorption tower 5 is supplied to the catalytic combustion apparatus 6 from a branch path 22 branched in the horizontal direction shown in the figure. Further, in the vicinity of the branch path 22 in the flow path 23 in which the dilution air flows, a tapered cylindrical body 20 that is a flow rate improving member that increases the flow rate of the dilution air is provided. And when dilution air passes the cylindrical body 20, a flow rate becomes quick, the negative pressure is given in the branch path 22 with the air flow, and exhaust gas is attracted | sucked.

  In this example, since the diluted air before being mixed with the exhaust gas is preheated by the ejector 11, the airflow can be preheated at a small stage, so that the heating efficiency is good, the heater can be downsized, and the energy efficiency can be improved. .

  While the exhaust gas treatment apparatus 1 is in operation, dilution air from the blower 12 and the first air introduction path 10 is constantly introduced into the first exhaust gas introduction path 9. By doing in this way, since dilution air always flows into the ejector 11 and the inside of the adsorption tower 5 is always sucked by the air flow, the exhaust gas from the adsorption tower 5 and the second exhaust gas introduction path 7 to the gas sterilizer 2 side. Therefore, the safety of the gas sterilizer 2 can be ensured. Moreover, since the inside of the adsorption tower 5 is always set to a negative pressure, leakage of exhaust gas from the adsorption tower 5 itself can be prevented, and contamination of the surrounding environment can be prevented.

  Further, in the exhaust gas treatment device, the exhaust gas discharged from the catalytic combustion device 6 and the exhaust gas diluted via the ejector 11 and introduced into the catalytic combustion device 6 are heat-exchanged and introduced into the catalytic combustion device 6. Is provided with a heat exchanger 4 for further preheating. The heat exchanger 4 is connected to a processing gas discharge path 16 for discharging a high-temperature processing gas from the catalytic combustion apparatus 6, and is connected to a first exhaust gas introduction path 9 connected to an ejector 11. Heat exchange is performed between the high-temperature processing gas discharged from 6 and the mixed gas of the exhaust gas discharged from the adsorption tower 5 and the diluted air preheated by the preheater 13 to further preheat the mixed gas. To the catalytic combustion device 6.

  The specific method of the heat exchanger 4 is not particularly limited, but a double tube method or a fin method that has a simple structure and is compact can be suitably used.

  Further, the exhaust gas treatment apparatus always controls the dilution air introduced from the second air introduction path 8 to the second exhaust gas introduction path 7 by the orifice 14 or flows from the first air introduction path 10 to the first exhaust gas introduction path 9. The dilution air to be introduced into the air is always flowed through the ejector 11.

  Further, in this apparatus, some trouble has occurred in the catalytic combustion apparatus 6 on the upstream side of the ejector 11 in the first exhaust gas introduction path 9 for introducing the exhaust gas from the adsorption tower 5 to the catalytic combustion apparatus 6 via the ejector 11. A third valve 24 for stopping the inflow of exhaust gas to the catalytic combustion device 6 is provided in an emergency such as time. And when troubles, such as abnormal temperature rise of the catalyst combustion apparatus 6, occur, the trouble is detected, the 2nd valve 19 and the 3rd valve 24 are closed, exhaust gas introduction into the adsorption tower 5, and the catalyst combustion apparatus Control is performed to stop the inflow of exhaust gas to 6 and to open the first valve 18. By doing in this way, when trouble arises in the catalytic combustion apparatus 6, inflow of exhaust gas is stopped, and higher safety can be secured.

  Further, in the above apparatus, the process gas discharge path 16 is provided with a fourth valve 25 that shuts off the communication with the atmosphere of the catalytic combustion apparatus 6 when the operation is stopped. The first air introduction passage 10 for introducing the air introduced from the blower 12 to the catalytic combustion apparatus 6 is provided with a fifth valve 26 for blocking the inflow of air to the catalytic combustion apparatus 6 when the operation is stopped.

  By doing in this way, deterioration of the catalyst with which the catalyst combustion apparatus 6 was filled can be prevented. That is, after the end of the steady operation, the catalyst is about 100 ° C. At this time, external air may enter the catalytic combustion apparatus through the processing gas discharge path 16. The outside air contains water vapor, pollutants, poisonous substances, and the like. When this air enters the catalytic combustion apparatus 6, the catalyst is exposed to an oxidizing atmosphere, and the deterioration of the catalyst is promoted. . Therefore, by controlling the fourth valve 25, the fifth valve 26, the second valve 19, and the third valve 24 to be closed when the operation is stopped, the inflow of air into the catalytic combustion apparatus 6 is completely performed after the operation is stopped. Thus, deterioration of the internal catalyst can be prevented, and long-term stable operation can be ensured.

  Using the exhaust gas treatment apparatus 1, the exhaust gas treatment method of the present invention can be performed, for example, as follows.

  Here, the operation pattern by the pressure fluctuation in the sterilization tank in the sterilization treatment and the exhaust gas treatment is shown in FIG.

  First, the sterilization process by the gas sterilizer 2 is performed.

  That is, the object to be sterilized is accommodated in the sterilization tank, the sterilization tank is sealed, the exhaust pump 3 is operated, and the air in the sterilization tank is discharged (step A in FIG. 3). At this time, in the exhaust gas treatment apparatus 1, the first valve 18 is opened and the second valve 19 and the third valve 24 are closed, and the exhaust gas is discharged from the exhaust gas passage 17. Next, the exhaust pump 3 is stopped, and ethylene oxide gas is introduced into the sterilization tank until the pressure is slightly lower than atmospheric pressure to fill the ethylene oxide gas (step B in FIG. 3). Then, sterilization is performed for a predetermined time (for example, about 2 to 4 hours) while the inside of the sterilization tank is maintained at a negative pressure slightly lower than atmospheric pressure (step C in FIG. 3).

  On the other hand, before the sterilization process is finished, the catalytic combustion device 6 and the preheater heater 13 of the exhaust gas treatment apparatus 1 are turned on to start preheating, and when the sterilization process is finished and the exhaust gas treatment is started, catalytic combustion is performed. The tank temperature of the apparatus 6 is set to a predetermined combustion temperature (for example, about 320 ° C.). At this time, the blower 12 also starts operation, introduces dilution air into the adsorption tower 5 via the second air introduction path 8, and introduces dilution air into the catalytic combustion apparatus 6 via the first air introduction path 10. Introduce.

  When the sterilization process is completed, the exhaust gas treatment apparatus 1 is prepared to close the first valve 18 and open the second valve 19 so that the exhaust gas treatment is possible. On the other hand, in the gas sterilizer 2, the ethylene oxide gas in the sterilization tank is discharged, and the discharged ethylene oxide gas is introduced into the exhaust gas treatment device 1 and detoxified.

  That is, the exhaust pump 3 is operated to exhaust the exhaust gas in the sterilization tank (step Da shown in the figure), and when the sterilization tank is depressurized to a predetermined degree of vacuum, the exhaust pump 3 is stopped or sterilized with the exhaust pump 3. The valve provided in the communication path of the tank is closed, and the atmosphere is introduced into the sterilization tank (step Db in the figure). This exhausting step (Da) and the air introduction step (Db) are repeated a predetermined number of times (for example, about 30 times) (D1, D2,... In the drawing) to perform aeration. At this time, each cycle of aeration (D1, D2,...) Of the exhaust process (Da) and the air introduction process (Db) takes about 4 to 5 minutes.

  The exhaust gas discharged from the exhaust pump 3 in the exhaust process (Da) is introduced into the adsorption process performed in the adsorption tower 5 through the exhaust gas path 17 and the second exhaust gas introduction path 7. At this time, diluted air is introduced into the second exhaust gas introduction passage 7 from the second air introduction passage 8, and exhaust gas diluted with the dilution air is introduced into the adsorption step.

  In the adsorption process, most of the ethylene oxide gas in the exhaust gas is adsorbed and removed by the adsorbent, and the adsorbed exhaust gas is introduced into the catalytic combustion process performed by the catalytic combustion device 6 through the first exhaust gas introduction path 9. . At this time, diluted air is introduced into the first exhaust gas introduction passage 9 from the first air introduction passage 10, and exhaust gas further diluted with the dilution air is introduced into the catalytic combustion process.

  The diluted air is preheated by the preheater 13 in advance and then introduced into the ejector 11. As described above, since the diluted air is introduced after being preheated by the preheater 13, the temperature reduction of the catalytic combustion apparatus 6 due to the introduction of the diluted air can be prevented, and the occurrence of a detoxification failure accident due to insufficient combustion. Can be prevented in advance, and safe removal can be ensured by ensuring detoxification.

  Further, by introducing the diluted air through the ejector 11 as described above, a negative pressure is applied to the exhaust gas discharged from the adsorption process by the air flow of the diluted air and sucked. By doing in this way, since the exhaust gas introduced into the catalytic combustion process in the catalytic combustion apparatus 6 is diluted with diluted air and the concentration is further reduced, the risk of ignition and explosion is further reduced, and safety is improved. Get higher.

  Further, by applying a negative pressure to the exhaust gas discharged from the adsorption process and sucking it, the adsorption process in the adsorption tower 5 is operated in a negative pressure state, and the backflow of ethylene oxide gas to the gas sterilizer 2 side is performed. And the safety of the gas sterilizer 2 can be secured. Moreover, since the negative pressure to the adsorption process in the adsorption tower 5 is generated by the air flow of dilution air, no special suction device or valve operation is required, and the backflow of sterilization gas due to troubles of those devices does not occur. Therefore, safety is extremely high.

  The mixed gas of the exhaust gas and the diluted air mixed by the ejector 11 is introduced into the heat exchanger 4 where heat is exchanged with the high-temperature processing gas discharged from the catalytic combustion device 6 and further preheated. . In this way, the exhaust gas discharged from the catalytic combustion device 6 and the exhaust gas diluted and introduced into the catalytic combustion device 6 are heat-exchanged, and the exhaust gas introduced into the catalytic combustion device 6 is further preheated. The amount of heating at 13 can be saved, energy efficiency is improved, and running costs are greatly reduced, while ensuring detoxification and ensuring safety.

  In the catalytic combustion process, the ethylene oxide gas in the exhaust gas is catalytically burned and rendered harmless, and is discharged from the high-temperature processing gas discharge path 16. As described above, the processing gas is introduced into the heat exchanger 4 and heat exchange is performed between the exhaust gas mixed in the ejector 11 and the mixed gas of diluted air.

  On the other hand, in the atmosphere introduction process (Db), exhaust gas exhaust from the exhaust pump 3 stops, but since the dilution air is constantly introduced into the adsorption process in the adsorption tower 5, the introduction of exhaust gas is interrupted. The diluted air can act as a desorbing gas for the adsorbent, and the ethylene oxide gas adsorbed on the adsorbent in the adsorption step can be desorbed by the diluted air to regenerate the adsorbent.

  Thus, since desorption is performed with diluted air that does not contain sterilization gas, the desorption efficiency is improved, and there is no need to provide heating means in the adsorption tower 5. Therefore, the danger of ignition and combustion is avoided and the safety is further improved. Furthermore, when dilution air is constantly introduced into the adsorption tower 5 or the adsorption process, the pressure fluctuation of the fluid in the exhaust gas treatment system is reduced and stabilized, and the aging of the apparatus can be prevented to some extent. Further, since the dilution air always flows in the catalytic combustion device 6 or the catalytic combustion process, the catalytic combustion device 6 can be prevented from being overheated and safety can be further improved.

  The ethylene oxide gas released from the adsorbent by desorption in the air introduction step (Db) is introduced into the catalytic combustion step performed in the catalytic combustion device 5 through the first exhaust gas introduction path 9 and rendered harmless. At this time, similarly to the above description, the diluted air is introduced from the first air introduction passage 10 into the first exhaust gas introduction passage 9, and the desorption gas diluted with the dilution air is introduced into the catalytic combustion process.

  Thereafter, the gas sterilizer 2 repeats the aeration in the exhaust process (Da) and the air introduction process (Db) to complete the discharge of the ethylene oxide gas in the sterilization tank. In the exhaust gas treatment device 1, exhaust gas is introduced along with the exhaust process (Da), and the ethylene oxide gas is rendered harmless by the adsorption process by the adsorption tower 5 and the catalytic combustion process by the catalytic combustion apparatus 6.

  Here, it is necessary to control the ethylene oxide concentration of the exhaust gas after dilution introduced into the catalytic combustion process to be always 3% or less, which is the explosion limit. Further, it is desirable to control the exhaust gas after adsorption discharged from the adsorption process and the ethylene oxide concentration of the desorption gas so that the explosion limit is always 3% or less.

  The concentration control of the ethylene oxide gas discharged from the adsorption tower 5 is performed by, for example, adjusting the flow rate of dilution air introduced from the second air introduction path 8 according to the size of the adsorption tower 5 and the type and amount of adsorbent to be filled. This can be realized by adjusting at 14.

  Thus, by controlling the amount of diluted air introduced so that the concentration of ethylene oxide gas discharged from the adsorption tower 5 is below the explosion limit, the risk of ignition and explosion can be almost completely eliminated. And in the negative pressure type gas sterilizer 2 using high-concentration ethylene oxide gas, the exhaust gas can be detoxified safely and efficiently, and the safety of the surrounding environment of the gas sterilizer 2 can be ensured.

  As described above, according to the exhaust gas treatment apparatus and method, when introducing the exhaust gas discharged from the adsorption tower 5 into the catalytic combustion apparatus 6, the diluted air preheated by the preheater 13 is introduced. In this way, after the sterilization gas such as ethylene oxide gas is adsorbed by the adsorption tower 5, the exhaust gas is further diluted with diluted air and introduced into the catalytic combustion device 6, so that the concentration of the sterilizing gas flowing through the catalytic combustion device 6 Greatly reduces the risk of ignition and explosion. Further, since the diluted air is introduced after being preheated by the preheater 13, the temperature reduction of the catalytic combustion apparatus 6 due to the introduction of the diluted air can be prevented, and the occurrence of a detoxification failure accident due to insufficient combustion can be prevented. It is possible to prevent and prevent detoxification and ensure safety. Further, since the exhaust gas discharged from the catalytic combustion device 6 and the exhaust gas diluted and introduced into the catalytic combustion device 6 are subjected to heat exchange, the exhaust gas introduced into the catalytic combustion device 6 is further preheated. The amount can be saved, energy efficiency can be improved, and running cost can be greatly reduced, while safe abatement can be performed to ensure safety.

  In addition, since the exhaust gas to be introduced into the adsorption process in the adsorption tower 5 is diluted with diluted air and introduced, the concentration of ethylene oxide gas flowing through the exhaust gas treatment system decreases overall, greatly increasing the risk of ignition and explosion. descend. Moreover, by always introducing dilution air into the adsorption process in the adsorption tower 5, the pressure fluctuation of the fluid in the exhaust gas treatment system is reduced and stabilized, and the aging of the apparatus can be prevented to some extent.

  In the apparatus and method of the above embodiment, the preheater 13 is provided in the first air introduction passage 10 and the diluted air is preheated and then introduced into the ejector 11. However, the present invention is not limited to this. 11, a preheating heater 13 may be provided in the first exhaust gas introduction passage 9 upstream of the heat exchanger 4 on the downstream side of the heat exchanger 4 to preheat the mixed gas of diluted air and exhaust gas.

  In the above embodiment, the gas sterilizer 2 is shown as an example using a negative pressure type sterilizer in which the inside of the sterilization tank is held at a slightly lower negative pressure than the atmospheric pressure for sterilization. However, the present invention is not limited thereto, and a positive pressure type sterilizer that performs sterilization by holding the inside of the sterilization tank at a slightly higher positive pressure than the atmospheric pressure can also be used.

  Moreover, although the example which used ethylene oxide gas as a sterilization gas of a gas sterilizer was shown in the said Example, it is not limited to this, Various gas will be applied if it has a sterilization effect | action Can do. Moreover, it is possible to use an appropriate adsorbent other than those exemplified in the above description according to the type of sterilization gas to be adsorbed.

It is a block diagram which shows one Example of the waste gas processing apparatus for sterilizers of this invention. It is a figure explaining the principle of an ejector. It is a figure which shows the driving | running pattern in a sterilization process and waste gas processing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Exhaust gas processing apparatus 2 Gas sterilizer 3 Exhaust pump 4 Heat exchanger 5 Adsorption tower 6 Catalytic combustion apparatus 7 2nd exhaust gas introduction path 8 2nd air introduction path 9 1st exhaust gas introduction path 10 1st air introduction path 11 Ejector 12 Blower (Or compressor)
DESCRIPTION OF SYMBOLS 13 Preheating heater 14 Orifice 15 Pressure gauge 16 Process gas discharge path 17 Exhaust gas path 18 1st valve 19 2nd valve 20 Cylindrical body 21 Check valve 22 Branch path 23 Flow path 24 3rd valve 25 4th valve 26 5th valve

Claims (8)

  An exhaust gas treatment method for a gas sterilizer for detoxifying exhaust gas from a gas sterilizer, an adsorption process for adsorbing sterilization gas in the exhaust gas, and catalytic combustion for catalytic combustion of the sterilization gas in the exhaust gas discharged from the adsorption process A first dilution step for introducing diluted air when introducing the exhaust gas discharged from the adsorption step into the catalytic combustion step, a preheating step for preheating the diluted air or a mixed gas of the exhaust gas and the diluted air, A heat exchanging step of further preheating the exhaust gas introduced into the catalytic combustion process by exchanging heat between the exhaust gas discharged from the catalytic combustion process and the exhaust gas diluted in the first dilution process and introduced into the catalytic combustion process. An exhaust gas treatment method for a gas sterilizer.   An exhaust gas treatment method for a gas sterilizer for detoxifying exhaust gas from a gas sterilizer, an adsorption process for adsorbing sterilization gas in the exhaust gas, and catalytic combustion for catalytic combustion of the sterilization gas in the exhaust gas discharged from the adsorption process A first dilution step for introducing dilution air when introducing the exhaust gas discharged from the adsorption step into the catalytic combustion step, and preheating the dilution air or a mixed gas of the exhaust gas and the dilution air in advance with a preheater An exhaust gas treatment method for a gas sterilizer, comprising a preheating step.   The second dilution step for introducing diluted air to the exhaust gas introduced into the adsorption step, the exhaust gas discharged from the catalyst combustion step, and the mixed gas diluted in the first dilution step and introduced into the catalyst combustion step are heated. The exhaust gas treatment method for a gas sterilizer according to claim 2, further comprising a heat exchange step of further preheating the mixed gas exchanged and introduced into the catalyst combustion step.   The gas sterilizer according to any one of claims 1 to 3, wherein the first dilution step sucks the exhaust gas discharged from the adsorption step by applying a negative pressure by the air flow of the dilution air. Exhaust gas treatment method.   An exhaust gas treatment apparatus for a gas sterilizer that detoxifies exhaust gas from a gas sterilizer, an adsorption tower that adsorbs the sterilization gas in the exhaust gas, and catalytic combustion that catalytically burns the sterilization gas in the exhaust gas discharged from the adsorption tower A first dilution means for introducing diluted air when the exhaust gas discharged from the adsorption tower is introduced into the catalytic combustion apparatus, a preheating heater for preheating the diluted air or a mixed gas of the exhaust gas and the diluted air, A heat exchanger for preheating the exhaust gas introduced into the catalytic combustion device by exchanging heat between the exhaust gas discharged from the catalytic combustion device and the exhaust gas diluted by the first dilution means and introduced into the catalytic combustion device. An exhaust gas treatment apparatus for a gas sterilizer,   An exhaust gas treatment apparatus for a gas sterilizer that detoxifies exhaust gas from a gas sterilizer, an adsorption tower that adsorbs the sterilization gas in the exhaust gas, and catalytic combustion that catalytically burns the sterilization gas in the exhaust gas discharged from the adsorption tower A first dilution means for introducing diluted air when introducing the exhaust gas discharged from the adsorption tower into the catalytic combustion apparatus, and a preheating heater for preheating the diluted air or a mixed gas of the exhaust gas and the diluted air. An exhaust gas treatment apparatus for a gas sterilizer, comprising:   The second dilution means for introducing diluted air to the exhaust gas introduced into the adsorption tower, the exhaust gas discharged from the catalytic combustion apparatus, and the mixed gas diluted by the first dilution means and introduced into the catalytic combustion apparatus are heated. The exhaust gas treatment apparatus for a gas sterilizer according to claim 2, further comprising a heat exchanger for further preheating the mixed gas exchanged and introduced into the catalyst combustion apparatus.   The gas sterilizer according to any one of claims 5 to 7, wherein the first diluting means is an ejector that sucks exhaust gas discharged from the adsorption tower by applying a negative pressure by an air flow of the diluted air. Exhaust gas treatment equipment.

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