JP2006263475A - Process and apparatus for treating residual anesthetic gas - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a process and an apparatus for treating a residual anesthetic gas containing a volatile anesthetic and nitrous oxide, discharged from an operating room. <P>SOLUTION: A waste anesthetic gas containing a volatile anesthetic and nitrous oxide is introduced into an adsorbing cylinder 1 filled with an adsorbent, where the volatile anesthetic contained in the residual anesthetic gas is adsorbed and thereby removed, and successively this gas is introduced into a catalyst layer 3 filled with a nitrous oxide decomposition catalyst, where nitrous oxide is decomposed into nitrogen and oxygen. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a treatment method and a treatment apparatus for excess anesthetic gas containing a volatile anesthetic and nitrous oxide discharged from an operating room.

Since 1960, anesthesia gas contamination in the operating room and the health problems of operating room workers have been taken up, and it has become known that health problems are caused by inhaling anesthetic gas leaked into the operating room for a long time. An anesthetic gas is a mixed gas containing nitrous oxide, a volatile anesthetic and oxygen, and an excess anesthetic gas refers to an anesthetic gas after the patient breathes. The composition of the surplus anesthetic gas is close to that of the anesthetic gas and contains volatile anesthetics, high concentrations of nitrous oxide and oxygen. In the United States, the National Institute of Occupational Safety and Health (NIOSH) has established environmental exposure standards, nitrous oxide (N ₂ O) is 25 ppm or less, volatile anesthetics are 2 ppm alone, and 0.5 ppm or less when used in combination with nitrous oxide. It is recommended to keep it down. For this reason, it is obliged to attach the surplus anesthetic gas exclusion device to all anesthesia machines, and it is now possible to make the operating room environment almost reach the above standard.

  The surplus anesthesia gas excluding device is a device that discharges the surplus anesthesia gas from the patient's exhalation to the outside with accompanying compressed air or the like. However, the current situation is that the gas removed from each operating room by the surplus anesthetic gas exclusion device is released to the atmosphere without any countermeasures.

The following two points are different between the excess anesthetic gas discharged from the operating room and the exhaust gas containing nitrous oxide discharged from the factory and incineration facilities.
(1) The concentration of nitrous oxide contained in the surplus anesthetic gas is very high at 3 to 70%,
(2) surplus anesthetic gas contains volatile anesthetic gas,
It is.

  Among volatile anesthetics, it is said that volatile anesthetics containing chlorine in particular may destroy the ozone layer. Recently, the issue of global warming has been highlighted. At the International Conference on the Prevention of Global Warming (COP3), nitrous oxide, together with nitrogen dioxide, methane, chlorofluorocarbon, etc., raises the temperature due to the greenhouse effect. It is particularly attracting attention as a global environmental pollutant that produces (300 times).

  Therefore, when discharging the surplus anesthetic gas using the surplus anesthetic gas exclusion device, the volatile anesthetic and nitrous oxide contained in the surplus anesthetic gas are not directly released to the atmosphere from the viewpoint of protecting the global environment. It is necessary to remove or detoxify both.

As a conventional surplus anesthetic gas treatment method,
(1) Methods for decomposing nitrous oxide contained in excess anesthetic gas are disclosed in JP 61-45486 (Patent Document 1), JP 61-45487 (Patent Document 2), and JP 61-50650. No. (Patent Document 3), Japanese Patent Publication No. 62-27844 (Patent Document 4), and the like. Also,
(2) Arai et al. Proposed a method for removing volatile anesthetics contained in excess anesthetic gas by cooling (Clinical Anesthesia Vol.1, No.1, P.98, 1977; Non-Patent Document 1). , Fujita Gakuen Medical Association Vol.5, P.117, 1981; Non-Patent Document 2). Also,
(3) As a treatment method that does not use a catalyst for the decomposition of nitrous oxide contained in excess anesthetic gas, a method of thermally decomposing nitrous oxide by heating with a nichrome wire has been reported (Anesthetic No. 28, p. 40). 1242, 1979; Non-Patent Document 3).

Although the method (1) for decomposing nitrous oxide is capable of decomposing high-concentration nitrous oxide, nitric oxide (NO) and nitrogen dioxide (NO ₂ ) (hereinafter referred to as “NOx”) which are nitrogen oxides. 5) to 32 ppm, and NOx in an amount exceeding the allowable NO ₂ concentration of 3 ppm (TWA: time weighted average) is generated. Further, if the reaction gas contains, for example, about 1 to 3% of water, the activity of the catalyst may be lowered, which leaves a problem.

  Further, if the surplus anesthetic gas is supplied to the nitrous oxide decomposition catalyst as it is, the specific surface area of the nitrous oxide decomposition catalyst may be reduced, and the activity may be significantly reduced. The reason is not clear, but it is presumed that the acid generated when the volatile anesthetic decomposes deactivates the nitrous oxide decomposition catalyst. Therefore, in order to maintain the activity of the nitrous oxide decomposition catalyst, it is necessary to remove the volatile anesthetic. However, there has been no method for effectively removing the volatile anesthetic contained in the excess anesthetic gas. unknown.

  The removal method (2) by cooling of the volatile anesthetic contained in the surplus anesthetic gas devised by Arai et al. Installs a volatile anesthetic gas remover and a cooling device for cooling the remover in each operating room. In addition to being economically problematic, it is not preferred in terms of location or hygiene to place a large device such as a cryogenic refrigeration device in the operating room. In addition, when processing a large flow rate of gas from a pipe that collects surplus anesthetic gas discharged from each operating room, it is difficult to remove the volatile anesthetic sufficiently due to the capacity of the refrigerator. There is a problem that there is, has not yet reached practical use.

  In addition, regarding the method (3) for thermally decomposing nitrous oxide by heating with nichrome wire without using a catalyst, the reaction temperature is as high as 900 ° C., a neutralization washing apparatus is necessary, and the concentration of NOx produced is For reasons such as a very high concentration of around 0.1%, it is not preferable for safety in hospital use.

A processing method and a processing apparatus that can continuously process a volatile anesthetic and nitrous oxide contained in a relatively large amount of excess anesthetic gas discharged from each operating room have not been known so far. Development of treatment methods and treatment equipment capable of continuously treating volatile anesthetics and surplus anesthetic gas containing nitrous oxide discharged from the operating room while interest in global warming due to nitrous oxide is increasing Is desired.
Japanese Examined Patent Publication No. 61-45486 Japanese Examined Patent Publication No. 61-45487 Japanese Patent Publication No. 61-50650 Japanese Examined Patent Publication No. 62-27844 Clinical Anesthesia Vol.1, No.1, P.98, 1977 Journal of Fujita Gakuen Medical Association Vol.5, P.117, 1981 Anesthesia No.28, p.1242, 1979

  The present invention has been made under such a background, and the present invention provides a method and an apparatus for treating excess anesthetic gas containing a volatile anesthetic and nitrous oxide discharged from an operating room. This is the issue.

As a result of intensive studies to solve the above problems, the present inventors, for example,
(1) Surplus anesthesia gas containing volatile anesthetic and nitrous oxide is introduced into at least one of the adsorbing cylinders connected in parallel and brought into contact with the adsorbent filled in the adsorbing cylinder. Adsorbing and removing volatile anesthetics contained in the gas;
(2) a step of decomposing nitrous oxide by contacting a gas containing nitrous oxide discharged from step (1) with a catalyst;
Using an excess anesthetic gas treatment method comprising:
An adsorption cylinder filled with an adsorbent that adsorbs a volatile anesthetic;
A decompression device for desorbing the adsorbed volatile anesthetic from the adsorbent and regenerating the adsorbent;
A cooler that liquefies or freezes the detached volatile anesthetic,
A recovery device for recovering liquefied or frozen volatile anesthetics;
A decomposition reactor filled with a catalyst for decomposing nitrous oxide contained in excess anesthetic gas;
The present invention has been completed by finding that the above-mentioned problems can be solved by using a processing apparatus equipped with The present invention relates to the following [1] to [33].

[1] A method for treating surplus anesthetic gas, wherein a surplus anesthetic gas containing a volatile anesthetic and nitrous oxide is brought into contact with an adsorbent and then brought into contact with a nitrous oxide decomposition catalyst.
[2] A method for treating surplus anesthetic gas, comprising the following two steps.
(1) A surplus anesthetic gas containing a volatile anesthetic and nitrous oxide is introduced into an adsorption cylinder, and the volatile anesthetic contained in the surplus anesthetic gas is brought into contact with the adsorbent filled in the adsorption cylinder. Adsorption and removal step (2) Step of decomposing nitrous oxide by contacting a gas containing nitrous oxide discharged from step (1) with a catalyst [3] The following two steps are included: How to treat excess anesthetic gas.
(1) Surplus anesthesia gas containing volatile anesthetic and nitrous oxide is introduced into at least one of the adsorbing cylinders connected in parallel and brought into contact with the adsorbent filled in the adsorbing cylinder. Step of desorbing volatile anesthetic contained in gas (2) Step of decomposing nitrous oxide by contacting gas containing nitrous oxide discharged from step (1) with a catalyst

[4] A method for treating excess anesthetic gas, comprising the following three steps:
(1) Surplus anesthesia gas containing volatile anesthetic and nitrous oxide is introduced into at least one of the adsorbing cylinders connected in parallel and brought into contact with the adsorbent filled in the adsorbing cylinder. Step (2) for removing volatile anesthetic contained in gas by adsorption (2) Step for decomposing nitrous oxide by contacting gas containing nitrous oxide discharged from step (1) with a catalyst (3) Volatilization The volatile anesthetic is desorbed from the adsorbent that has adsorbed the sexual anesthetic to regenerate the adsorbent, and the desorbed volatile anesthetic is cooled and liquefied or frozen to recover the volatile anesthetic. Step [5] The excess anesthesia according to [4] above, wherein the steps (1) and (3) are performed simultaneously by alternately switching the suction cylinders connected in parallel to the steps (1) and (3). Gas processing method.
[6] The surplus anesthetic gas treatment method according to [5], wherein the switching between the step (1) and the step (3) is controlled by a sequencer.

[7] The step (3) is performed under reduced pressure, and the gas discharged from the step (3) is introduced into at least one of the adsorption cylinders connected in parallel and brought into contact with the adsorbent filled in the adsorption cylinder The surplus anesthetic gas treatment method according to any one of the above [4] to [6], wherein the unrecovered volatile anesthetic contained in the gas discharged from the step (3) is removed by adsorption.
[8] The purge gas is introduced under reduced pressure to perform step (3), and the gas discharged from step (3) is introduced into at least one of the adsorption cylinders connected in parallel, and the adsorption cylinder is filled. Any of the above-mentioned [4] to [6], wherein the unrecovered volatile anesthetic contained in the gas containing the purge gas discharged from the step (3) is removed by adsorption by contacting with the adsorbent. Of excess anesthetic gas treatment.
[9] The method for treating excess anesthetic gas according to any one of the above [4] to [8], wherein in step (3), the temperature at which the detached volatile anesthetic is cooled is -95 to 10 ° C.
[10] The method for treating excess anesthetic gas according to any one of [1] to [9] above, wherein the concentration of the volatile anesthetic contained in the excess anesthetic gas is 0.1 to 3%.

[11] The method for treating excess anesthetic gas according to any one of the above [1] to [10], wherein the volatile anesthetic is fluoroether.
[12] The volatile anesthetic is 1,1,1-trifluoro-2-bromo-2-chloroethane, 1-chloro-2,2,2-trifluoroethyl difluoromethyl ether and / or fluoromethyl-2, The method for treating an excess anesthetic gas according to any one of the above [1] to [10], which is 2,2-trifluoro-1- (trifluoromethyl) ethyl ether.
[13] Treatment of excess anesthetic gas according to any one of [1] to [12], wherein the adsorbent is at least one adsorbent selected from the group consisting of activated carbon, zeolite, silica, mesoporous silica, and alumina. Method.
[14] The method for treating an excess anesthetic gas according to the above [13], wherein the adsorbent has a pore diameter of 5 to 100 mm.
[15] The method for treating excess anesthetic gas according to any one of the above [1] to [14], wherein the concentration of nitrous oxide contained in the excess anesthetic gas is 3 to 70%.
[16] The method for treating excess anesthetic gas according to any one of the above [1] to [15], wherein the catalyst for decomposing nitrous oxide is an alumina catalyst.

[17] The surplus anesthetic gas according to any one of [1] to [16] above, wherein the catalyst for decomposing nitrous oxide is at least one catalyst selected from the group consisting of the following (I) to (III): Processing method.
(I) Catalyst in which aluminum, magnesium and rhodium are supported on a carrier (II) Catalyst in which magnesium and rhodium are supported on an alumina carrier (III) Spinel-type crystalline composite oxide comprising at least part of aluminum and magnesium [18] The catalyst in which rhodium is supported on the carrier on which is formed [18] The above catalyst, wherein the catalyst for decomposing nitrous oxide is at least one catalyst selected from the group consisting of the following (IV) to (VI): 1]-[16]
(IV) at least one metal selected from the group consisting of zinc, iron and manganese, and a catalyst in which aluminum and rhodium are supported on a carrier. (V) at least one metal selected from the group consisting of zinc, iron and manganese; The spinel-type crystalline composite oxide is formed by at least a part of the catalyst (VI) aluminum in which rhodium is supported on an alumina carrier and at least one metal selected from the group consisting of zinc, iron and manganese. Catalyst in which rhodium is supported on a carrier [19] The method for treating excess anesthetic gas according to any one of [1] to [18] above, wherein the decomposition temperature of nitrous oxide is 200 to 600 ° C.

[20] The method for treating excess anesthetic gas according to any one of the above [17] to [19], wherein the amount of NOx produced during the decomposition of nitrous oxide is 1 ppm or less.
[21] In the step (2), heat exchange is performed between the gas discharged from the step (1) and the gas discharged from the step (2) after decomposing nitrous oxide. A method for treating surplus anesthetic gas according to any one of the above.
[22] The above [1] to [21], wherein the concentration of nitrous oxide contained in the gas after decomposing nitrous oxide is detected, and the decomposition temperature of nitrous oxide is controlled based on the detected concentration of nitrous oxide. ] The processing method of the surplus anesthetic gas in any one of.
[23] In an apparatus for treating excess anesthetic gas containing a volatile anesthetic and nitrous oxide, an adsorption cylinder filled with an adsorbent that adsorbs the volatile anesthetic;
A decompression device for desorbing the adsorbed volatile anesthetic from the adsorbent and regenerating the adsorbent;
A cooler that liquefies or freezes the detached volatile anesthetic,
A recovery device for recovering liquefied or frozen volatile anesthetics;
A decomposition reactor filled with a catalyst for decomposing nitrous oxide contained in excess anesthetic gas;
An excess anesthetic gas treatment device comprising:
[24] Excess anesthetic gas containing volatile anesthetic and nitrous oxide is introduced into the adsorption cylinder filled with the adsorbent, and then the gas containing nitrous oxide discharged from the adsorption cylinder is decomposed into nitrous oxide The surplus anesthetic gas treatment device according to [23], wherein the adsorption cylinder and the decomposition reactor are connected so as to be introduced into the decomposition reactor filled with the catalyst.

[25] The surplus anesthesia gas treatment device according to [23] or [24], further including a plurality of adsorption cylinders connected in parallel.
[26] The above [23] to [23] comprising a line for cooling the volatile anesthetic desorbed from the adsorbent and returning the gas after the volatile anesthetic is recovered by liquefaction or freezing to the inlet side of the adsorption cylinder 25] The surplus anesthetic gas treatment device according to any one of [25].
[27] A purge gas introduction line is provided and connected so that the purge gas is introduced into the adsorption cylinder, and the volatile anesthetic desorbed from the adsorbent is cooled and liquefied or frozen to recover the volatile anesthetic. The surplus anesthesia gas processing apparatus according to any one of the above [23] to [25], further comprising a line for returning a gas containing a later purge gas to the inlet side of the adsorption cylinder.
[28] The surplus anesthetic gas according to any one of [23] to [27], further comprising a dilution gas induction pump for diluting a gas to be introduced into the decomposition reactor and a line for introducing the dilution gas into the inlet of the decomposition reactor Processing equipment.
[29] The surplus anesthetic gas according to any one of [23] to [28], further including a heat exchanger for exchanging heat between the gas introduced into the decomposition reactor and the gas discharged from the decomposition reactor Processing equipment.

[30] In the above [29], the cracking reactor and the heat exchanger have an integral structure, and heat exchange is performed between the gas introduced into the cracking reactor and the gas discharged from the cracking reactor in the heat exchanger. The excess anesthetic gas treatment device as described.
[31] A nitrous oxide gas detector for detecting the concentration of nitrous oxide contained in the gas discharged from the decomposition reactor is provided, and based on the concentration of nitrous oxide measured by the nitrous oxide gas detector The surplus anesthetic gas processing apparatus according to any one of the above [23] to [30], further comprising a temperature control device for controlling the temperature of the decomposition reactor.
[32] The surplus according to any one of [23] to [31], wherein the adsorbent filled in the adsorption cylinder is at least one adsorbent selected from the group consisting of activated carbon, zeolite, silica, mesoporous silica, and alumina. Anesthetic gas treatment device.
[33] The above [23] to [32], wherein the catalyst charged in the cracking reactor is an alumina catalyst or at least one catalyst selected from the group consisting of the following (I) to (VI): Excess anesthetic gas treatment device.
(I) Catalyst in which aluminum, magnesium and rhodium are supported on a carrier (II) Catalyst in which magnesium and rhodium are supported on an alumina carrier (III) Spinel-type crystalline composite oxide comprising at least part of aluminum and magnesium Catalyst (IV) on which rhodium is supported on the support on which is formed, at least one metal selected from the group consisting of zinc, iron and manganese, and catalyst (V) zinc on which aluminum and rhodium are supported on the support At least one metal selected from the group consisting of iron and manganese, at least a part of catalyst (VI) aluminum in which rhodium is supported on an alumina support, and at least one selected from the group consisting of zinc, iron and manganese Rhodium is added to the carrier on which the spinel crystalline composite oxide is formed by the metal. Catalysts are lifting

  By using the surplus anesthetic gas treatment method and treatment apparatus of the present invention, the volatile anesthetic contained in the surplus anesthetic gas discharged from the hospital operating room by the surplus anesthetic gas exclusion device is adsorbed and removed by the adsorbent, and then Nitrous oxide can be decomposed into nitrogen and oxygen. By using the method and apparatus for treating surplus anesthetic gas of the present invention, from the viewpoint of protecting the global environment, volatile anesthetics that may destroy the ozone layer and nitrous oxide, which is a global warming gas, in the atmosphere. It can be rendered harmless without being released. In addition, the treatment apparatus of the present invention is compact and can be installed in hospital facilities such as hospital rooftops, machine rooms, and piping gathering spaces, and it can continuously process a large amount of excess anesthetic gas. It is economical because it can be done.

  The present invention will be described in detail below. First, the processing method of the surplus anesthetic gas containing a volatile anesthetic and nitrous oxide according to the present invention will be described.

  The surplus anesthetic gas treatment method of the present invention is characterized in that a surplus anesthetic gas containing a volatile anesthetic and nitrous oxide is brought into contact with an adsorbent and then brought into contact with a nitrous oxide decomposition catalyst. Further, the surplus anesthetic gas treatment method of the present invention introduces a surplus anesthetic gas containing a volatile anesthetic and nitrous oxide into an adsorption cylinder, and makes contact with the adsorbent filled in the adsorption cylinder. Step (1) of adsorbing and removing volatile anesthetic contained therein is performed, and then the gas containing nitrous oxide discharged from Step (1) is put into a decomposition reactor filled with a nitrous oxide decomposition catalyst. The step (2) of decomposing nitrous oxide into nitrogen and oxygen by introducing and bringing nitrous oxide into contact with a catalyst is performed. Furthermore, the method for treating surplus anesthetic gas according to the present invention introduces surplus anesthetic gas containing a volatile anesthetic and nitrous oxide into at least one of the adsorption cylinders connected in parallel, and fills the adsorption cylinder with the surplus anesthetic gas. The step (1) of adsorbing and removing the volatile anesthetic contained in the surplus anesthetic gas by bringing it into contact with the adsorbent thus made is performed, and then the gas containing nitrous oxide discharged from the step (1) is removed. The step (2) of introducing a nitrous oxide decomposition catalyst into a cracking reactor and bringing the nitrous oxide into contact with the catalyst to decompose the nitrous oxide into nitrogen and oxygen is performed.

  As a volatile anesthetic mixed with nitrous oxide, halocene (1,1,1-trifluoro-2-bromo-2-chloroethane) has been used conventionally, but in recent years, isoflurane (1-chloro-2) has been used. , 2,2-trifluoroethyl difluoromethyl ether), sevoflurane (fluoromethyl-2,2,2-trifluoro-1- (trifluoromethyl) ethyl ether), enflurane (2-chloro-1,1,2- Fluoroethers such as trifluoroethyl difluoromethyl ether) and desflurane (1,2,2,2-tetrafluoroethyl difluoromethyl ether) are mainly used. These fluoroether volatile anesthetics, for example, supply oxygen to an anesthesia machine filled with the fluoroether volatile anesthetic so that it is contained in anesthetic gas in an amount of 2 to 3%. -Use tellurium volatile anesthetics mixed with nitrous oxide.

  The amount of each component used as an anesthetic gas in the operating room is, for example, 4 L / min for nitrous oxide, 2 L / min for oxygen, and 2-3% of the total anesthetic gas amount for volatile anesthetics. Moreover, the density | concentration of the volatile anesthetic contained in the surplus anesthetic gas after being used as an anesthetic gas is 0.1 to 3%. For example, if the concentration of volatile anesthetic contained in excess anesthetic gas is 3%, and if one operation takes 8 hours, the amount of volatile anesthetic used per operating room is volatile anesthetic. For example, when sevoflurane is used as the agent, the gas is about 90 L and the liquid is about 771 g. If all of this sevoflurane is removed by adsorption only with activated carbon, the amount of activated carbon used is about 9 for coconut shell charcoal Y-10 (Ajinomoto Fine Techno Co., Ltd.), for example. 3Kg is required.

  Excess anesthetic gas discharged from the operating room is often released out of the hospital by piping that combines each operating room.If surgery is performed at the same time or if surgery is performed for a long time, Therefore, there is a problem in that a very large amount of activated carbon that is many times larger than the above is required, and it is very time-consuming and expensive to replace the activated carbon after each operation.

  In the method for treating surplus anesthetic gas of the present invention, the number of adsorption cylinders for adsorbing the volatile anesthetic contained in the surplus anesthetic gas may be one, but in order to treat surplus anesthetic gas continuously and efficiently For the above reasons, it is preferable to use a plurality of adsorption cylinders of two or more cylinders, and it is preferable that the plurality of adsorption cylinders of two or more cylinders are connected in parallel. Two or more suction cylinders connected in parallel can be operated by periodically switching them during operation. The size of the adsorption cylinder and the amount of the adsorbent filled in the adsorption cylinder can be appropriately selected according to the flow rate of excess anesthetic gas, the concentration of the volatile anesthetic agent, etc. so that the volatile anesthetic does not flow out from the outlet of the adsorption cylinder. it can. In order to efficiently adsorb the volatile anesthetic agent, it is preferable to perform the operation by switching the gas flow to a new adsorption cylinder at the time when about 3/4 of the adsorption capacity of the adsorbent is adsorbed. Can be operated.

Examples of the adsorbent that can be used in the method for treating surplus anesthetic gas of the present invention include zeolite, silica, mesoporous silica, alumina, activated carbon and the like, and at least one adsorbent selected from these adsorbents. Can be used. Preferably, activated carbon or alumina is used. In the case of activated carbon, one with less ash is preferable. The ash content is preferably 1% by mass or less, more preferably 0.5% by mass or less, and particularly preferably 0.2% by mass or less. The ash content is the inorganic components contained in the activated carbon, for example, include _{SiO 2, Al 2 O 3,} Fe 2 O 3, CaO, MgO, K 2 O, Na 2 O, and TiO _2, Cr ₂ O ₃ be able to. Among these inorganic components, it is preferable that the content of alkali metal and alkaline earth metal compound is small. When the adsorption / desorption operation of the volatile anesthetic is repeated using activated carbon rich in alkali metals and / or alkaline earth metals, the volatile anesthetic may be decomposed. Similarly, in the adsorbent other than activated carbon, the content of alkali metal and / or alkaline earth metal is preferably small, preferably 300 ppm or less, more preferably 100 ppm or less, and even more preferably 50 ppm or less. The adsorbent has a pore size of 5 to 100 cm, preferably 7 to 50 cm, and more preferably 7 to 20 cm based on the molecular size of the volatile anesthetic agent. When the excess anesthetic gas contains moisture, the excess anesthetic gas may be cooled before the adsorption treatment, or moisture may be removed by contacting with an adsorbent such as silica gel or hydrophilic zeolite. . Further, the adsorbent may be used alone or in combination of two or more at any ratio. The ratio of mixing two or more kinds of adsorbents can be appropriately selected from conditions such as the concentration of the volatile anesthetic agent.

The gas containing nitrous oxide obtained by contacting and removing the volatile anesthetic from the surplus anesthetic gas by contacting with the adsorbent is then decomposed into nitrogen and oxygen using a nitrous oxide decomposition catalyst. As the nitrous oxide decomposition catalyst, for example, an alumina catalyst in which a noble metal is supported on alumina can be used. Also, at least one catalyst selected from the group consisting of the following (I) to (III) can be used.
(I) Catalyst in which aluminum, magnesium and rhodium are supported on a carrier (II) Catalyst in which magnesium and rhodium are supported on an alumina carrier (III) Spinel-type crystalline composite oxide comprising at least part of aluminum and magnesium A catalyst in which rhodium is supported on a support on which is formed

Also, at least one catalyst selected from the group consisting of the following (IV) to (VI) can be used.
(IV) at least one metal selected from the group consisting of zinc, iron and manganese, and a catalyst in which aluminum and rhodium are supported on a carrier. (V) at least one metal selected from the group consisting of zinc, iron and manganese; The spinel-type crystalline composite oxide is formed by at least a part of the catalyst (VI) aluminum in which rhodium is supported on an alumina carrier and at least one metal selected from the group consisting of zinc, iron and manganese. Catalyst with rhodium supported on the support

  When decomposing nitrous oxide, NOx in an amount exceeding the permissible concentration may be generated. In order to reduce the amount of NOx produced to 1 ppm or less, the above-mentioned (I It is preferable to use at least one of the catalysts of () to (VI).

  The temperature of the decomposition reactor filled with the nitrous oxide decomposition catalyst can be set in the range of 200 to 600 ° C, preferably 300 ° C to 500 ° C, more preferably 350 ° C to 450 ° C. . By setting the temperature of the decomposition reactor filled with the catalyst within this temperature range, nitrous oxide can be decomposed efficiently, and if the above decomposition catalyst is used, the amount of NOx produced is reduced to 1 ppm or less. can do. When the temperature of the decomposition reactor is lower than 200 ° C., nitrous oxide is not decomposed sufficiently, and when the temperature is higher than 600 ° C., the life of the catalyst is shortened and the temperature in the hospital facility is higher than 600 ° C. This is not preferable from the viewpoint of safety.

  The concentration of nitrous oxide contained in the anesthetic gas is used in the range of 3 to 70%. The surplus anesthetic gas discharged from the surplus anesthesia gas exclusion device is adsorbed and removed from the volatile anesthetic agent and then introduced into the nitrous oxide decomposition reactor. The concentration of nitric oxide can be as high as about 25% despite the fact that it is diluted with compressed air as described above. Considering the decomposition ability of the catalyst, there is no problem even if it is introduced into the catalyst layer as it is, but considering the activity of the catalyst and the life of the catalyst, the concentration of nitrous oxide introduced into the catalyst layer is preferably lower. Therefore, the gas introduced into the nitrous oxide decomposition reactor is diluted, and the nitrous oxide concentration is preferably 10% or less, more preferably 5% or less.

  The gas for diluting the gas containing nitrous oxide is not particularly limited as long as it does not affect the catalyst. For example, air, nitrogen, or an inert gas such as helium or argon can be used. From the economical aspect, it is preferable to use dry air or air as it is.

  Moreover, the temperature of the gas introduced into the nitrous oxide decomposition reactor is substantially normal temperature, and the gas decomposed by the catalyst is heated to 200 to 600 ° C. In the treatment method of the present invention, both the gas before and after being introduced into the cracking reactor are passed through a heat exchanger installed at the entrance and exit of the cracking reactor, thereby decomposing the gas introduced into the cracking reactor. By exchanging heat with the gas discharged from the reactor, the heating energy and the cooling energy can be reduced to increase the energy efficiency.

  Furthermore, the treatment method of the present invention detects the concentration of nitrous oxide before releasing the decomposition gas discharged from the decomposition reactor into the atmosphere, and controls the reaction temperature of the decomposition reactor based on this detected concentration. can do. Nitrous oxide discharged from the outlet of the decomposition reactor is monitored to detect a decrease in the activity of the nitrous oxide decomposition catalyst, and control is performed such as raising the decomposition reaction temperature depending on the detected concentration of nitrous oxide.

Further, the method for treating surplus anesthetic gas according to the present invention comprises:
A surplus anesthetic gas containing a volatile anesthetic and nitrous oxide is first introduced into at least one of the adsorption cylinders connected in parallel, and the surplus anesthetic gas is brought into contact with the adsorbent filled in the adsorption cylinder. The step (1) of adsorbing and removing the volatile anesthetic contained in the surplus anesthetic gas is performed,
Performing the step (2) of decomposing nitrous oxide by bringing the gas containing nitrous oxide discharged from the step (1) into contact with the catalyst;
The volatile anesthetic is desorbed from the adsorbent adsorbed with the volatile anesthetic by performing the step (1) to regenerate the adsorbent, and the desorbed volatile anesthetic is cooled and liquefied or frozen. And performing step (3) of recovering the volatile anesthetic,
It is characterized by that.

  It is preferable to perform the step (1) and the step (3) simultaneously by alternately switching the suction cylinders connected in parallel to the step (1) and the step (3). Step (3) can regenerate the adsorbent by, for example, depressurizing the adsorbent adsorbed with the volatile anesthetic with a vacuum pump and desorbing the adsorbed volatile anesthetic. In other words, desorbing and recovering the volatile anesthetic from the adsorbent means, at the same time, regeneration of the adsorbent, and the adsorbent after desorbing the volatile anesthetic is again removed from the excess anesthetic gas. It can be reused as an adsorbent to remove the agent. Therefore, while the adsorbent is being regenerated, if the gas flow is switched to a new adsorbent and operated, regeneration of the adsorbent and recovery of the desorbed volatile anesthetic without stopping the processing equipment operation Processing can be performed almost simultaneously. Switching of each process can be performed by controlling a solenoid valve with a sequencer, for example.

  Further, in the step (3), for example, when the adsorption cylinder filled with the adsorbent is depressurized by a vacuum pump, a purge gas is introduced into the adsorption cylinder and the adsorbing volatile anesthetic is desorbed. Can be played. The purge gas is not particularly limited, but for example, air, nitrogen, inert gas, etc. can be used. From the economical aspect, it is preferable to use dry air or air as it is.

  Further, the present invention regenerates the adsorbent by desorbing the volatile anesthetic adsorbed on the adsorbent from the adsorbent and introducing the desorbed volatile anesthetic into the cooling device. The agent can be recovered by liquefaction or freezing. The recovered volatile anesthetic may be purified again, or it can be decomposed by incineration or contact with a decomposition agent.

  Most of the volatile anesthetics released from the adsorbent and introduced into the cooling device are liquefied or frozen, but the gas discharged from the cooling device contains volatile anesthetics corresponding to the vapor pressure at the cooling temperature. Yes. Although this amount is small, the exhaust gas from the cooling device is introduced into at least one of the adsorption cylinders connected in parallel, and is brought into contact with the adsorbent filled in the adsorption cylinder, thereby being discharged from the cooling apparatus. The volatile anesthetic agent remaining in the exhaust gas can be substantially free from the exhaust gas. In addition, as described above, purge gas can be used as a method for regenerating the adsorbent by desorbing the volatile anesthetic from the adsorbent. In this case, the gas containing the volatile anesthetic is cooled and volatile anesthetic is used. The gas that has been recovered by liquefying or freezing the agent is introduced into at least one of the adsorbing cylinders connected in parallel, and brought into contact with the adsorbent filled in the adsorbing cylinder. It can be made substantially free of sexual anesthetics.

  In addition, when the gas containing nitrous oxide after adsorbing and removing the volatile anesthetic is brought into contact with the nitrous oxide decomposition catalyst, the gas containing nitrous oxide is further introduced into the guard adsorption cylinder filled with the adsorbent. May be. By using the guard adsorption cylinder, it is possible to prevent the volatile anesthetic from flowing into the nitrous oxide decomposition catalyst even when the adsorption cylinder breaks through. There are no restrictions on the number and capacity of the guard adsorption cylinders, and the guard adsorption cylinders can be selected according to the operating conditions.

  The temperature for cooling the volatile anesthetic desorbed from the adsorbent can be effectively collected by setting the temperature to -95 to 10 ° C, preferably -90 to 5 ° C, more preferably Is preferably -40 to 5 ° C, particularly preferably -20 to 5 ° C. Since the efficiency of recovering the volatile anesthetic is improved when the cooling temperature is as low as possible, it may be cooled to, for example, below the freezing point of the volatile anesthetic, but at least 10 due to problems such as the capacity of the refrigerator and heat loss. It is preferable to set it as below ℃. In addition, when the gas containing the desorbed volatile anesthetic contains moisture, dehydration treatment may be performed by water absorption or cooling before the volatile anesthetic is cooled. It is possible to collect both volatile anesthetics and moisture by setting the above to the above temperature range. Further, as described above, the unrecovered volatile anesthetic agent corresponding to the vapor pressure at the cooling temperature can be almost completely adsorbed and removed by bringing it into contact with the adsorbent together with the purge gas, for example.

  On the other hand, if an attempt is made to remove the volatile anesthetic only by cooling without first treating with the adsorbent, for example, when the volatile anesthetic is sevoflurane, about 100 ppm sevoflurane even when cooled to -90 ° C. Remains in the cooled gas. Although the instantaneous value is slight, it is not preferable that the gas in which the volatile anesthetic remains is brought into contact with the nitrous oxide decomposition catalyst for a long time as it causes a decrease in the activity of the catalyst. Since the surplus anesthetic gas treatment method of the present invention can be removed by adsorbing a volatile anesthetic, it is not necessary to cool the cooling temperature to a cryogenic temperature lower than -95 ° C., which is economically preferable.

  Although there is no restriction | limiting in particular as a method of cooling a volatile anesthetic, For example, the method of using denatured alcohol as a refrigerant | coolant and cooling using dry ice or liquid nitrogen can be used. For ease of handling, a two-way cooler or a dedicated cryogenic cooler may be used.

Next, the excessive anesthetic gas treatment apparatus of the present invention will be described. The surplus anesthetic gas treatment device of the present invention is a device for treating surplus anesthetic gas containing a volatile anesthetic and nitrous oxide,
An adsorption cylinder filled with an adsorbent that adsorbs a volatile anesthetic;
A decompression device for desorbing the adsorbed volatile anesthetic from the adsorbent and regenerating the adsorbent;
A cooler that liquefies or freezes the detached volatile anesthetic,
A recovery device for recovering liquefied or frozen volatile anesthetics;
A decomposition reactor filled with a catalyst for decomposing nitrous oxide contained in excess anesthetic gas;
It is provided with.

  In an adsorption cylinder filled with an adsorbent that adsorbs volatile anesthetics and a decomposition reactor filled with a catalyst that decomposes nitrous oxide, excess anesthetic gas is first introduced into the adsorption cylinder and then discharged from the adsorption cylinder. The nitrous oxide-containing gas is connected to be introduced into a cracking reactor filled with a nitrous oxide cracking catalyst. Moreover, it is preferable that one or a plurality of adsorption cylinders filled with an adsorbent that adsorbs a volatile anesthetic is provided, and the plurality of adsorption cylinders are preferably connected in parallel so that any adsorption cylinder can be used. The gas flow can be changed.

  Hereinafter, the excessive anesthetic gas treatment apparatus of the present invention will be described with reference to the drawings. FIG. 1 shows the surplus anesthetic gas treatment of the present invention that adsorbs and removes a volatile anesthetic from a surplus anesthetic gas containing a volatile anesthetic and nitrous oxide, which is discharged from an operating room, and subsequently decomposes nitrous oxide. An example of an apparatus is shown. The excess anesthetic gas treatment apparatus shown in FIG. 1 includes an adsorption cylinder 1 filled with an adsorbent for adsorbing and removing a volatile anesthetic, a nitrous oxide decomposition reactor 3 filled with a nitrous oxide decomposition catalyst, and heat exchange. A diluting gas induction pump 5 for diluting a gas containing nitrous oxide, a flow meter 4, a diluting gas inlet 6, and nitrous oxide for measuring the concentration of nitrous oxide in exhaust gas after decomposition of nitrous oxide A device composed of a gas detector 7 and used for a surplus anesthetic gas treatment process, a cryogenic refrigerator 9, a cooler 2 for cooling a volatile anesthetic, and a recovery device 8 for recovering the cooled volatile anesthetic The apparatus is composed of a vacuum pump 10 and a device used for the step of desorbing and recovering the volatile anesthetic adsorbed on the adsorbent and simultaneously regenerating the adsorbent.

  The surplus anesthetic gas treatment apparatus of FIG. 1 includes one adsorption cylinder for adsorbing a volatile anesthetic, and surplus anesthetic gas is introduced into the adsorption cylinder 1 via a valve V6 and via a valve V7. And introduced into the nitrous oxide decomposition reactor 3. The time for the adsorption treatment can be set by the adsorption capacity of the adsorbent. As described above, in order to efficiently adsorb the volatile anesthetic agent, the adsorbent adsorption capacity is about 3/4 of the adsorption capacity. It is preferable to stop the process.

  As a method for recovering the volatile anesthetic adsorbed by the adsorbent, after the valve V6 is closed and the supply of surplus anesthetic gas is stopped, for example, the valve V7 is closed and the dilution gas is supplied via the valve V3. While being introduced, the volatile anesthetic is desorbed, and the desorbed volatile anesthetic is introduced into the cooler 2 via the valve V2 and is recovered by the volatile anesthetic recovery device 8. The adsorbent regenerated by removing the volatile anesthetic can be used repeatedly, and the valves V2 and V3 are closed and the valves V6 and V7 are opened to resume the treatment of the excess anesthetic gas.

  FIG. 2 shows an example of the surplus anesthetic gas treatment apparatus of the present invention, and shows an apparatus in which a guard adsorption cylinder 16 is added to the surplus anesthetic gas treatment apparatus shown in FIG. If the installation place of a guard adsorption cylinder is between adsorption cylinder 1 and nitrous oxide decomposition reactor 3, there will be no restriction in particular, and it can be prepared when an adsorption cylinder breaks through.

  FIG. 3 shows an example of the surplus anesthetic gas treatment apparatus of the present invention. The surplus anesthetic gas treatment apparatus shown in FIG. 3 includes an adsorption cylinder 1 filled with an adsorbent for adsorbing and removing volatile anesthetics, a nitrous oxide decomposition reactor 3 filled with a nitrous oxide decomposition catalyst, and heat exchange. A diluting gas induction pump 5 for diluting a gas containing nitrous oxide, a flow meter 4, a diluting gas inlet 6, and nitrous oxide for measuring the concentration of nitrous oxide in exhaust gas after decomposition of nitrous oxide A device composed of a gas detector 7 and used for a surplus anesthetic gas treatment process, a cryogenic refrigerator 9, a cooler 2 for cooling a volatile anesthetic, and a recovery device 8 for recovering the cooled volatile anesthetic The apparatus is composed of a vacuum pump 10 and a device used for the step of desorbing and recovering the volatile anesthetic adsorbed on the adsorbent and simultaneously regenerating the adsorbent.

  The surplus anesthetic gas treatment apparatus of FIG. 3 includes two adsorption cylinders for adsorbing volatile anesthetic agents, and the adsorption cylinder (A) and the adsorption cylinder (B) are connected in parallel. Switching between the adsorption cylinders (A) and (B) can be performed with the valve V1. For example, during the adsorption operation with the adsorption cylinder (A), the volatile anesthetic agent can be desorbed and collected from the adsorption cylinder (B). In order to regenerate the adsorbent and operate the processing equipment continuously.

  The adsorbent filled in the adsorption cylinder can be selected according to the type of the volatile anesthetic contained in the surplus anesthetic gas, and the valve V1 of the two systems (A) and (B) of the adsorption cylinder 1 can be selected. -V4 is controlled, surplus anesthetic gas is introduced into the adsorption cylinder (A) from the (A) side of the valve V1, for example, and the volatile anesthetic is first removed by adsorption. The gas from which the volatile anesthetic is adsorbed and removed in the adsorption cylinder (A) is introduced into the decomposition reactor 3 filled with the nitrous oxide decomposition catalyst via the valve V4. In the meantime, the (B) side of the valve V1 and the (B) side of the valve V4 are closed.

  The decomposition reactor 3 can be heated by, for example, an electric heater. As the catalyst charged in the decomposition reactor 3, for example, an alumina catalyst in which a noble metal is supported on alumina, a catalyst in which magnesium and rhodium are supported on an alumina carrier, or the like can be used. The gas containing nitrous oxide introduced into the decomposition reactor 3 can be diluted while taking the atmosphere from the dilution gas inlet 6 by the dilution gas induction pump 5 and controlling the flow rate by the flow meter 4.

  Valves V1 and V4 are used for switching between the two surplus anesthetic gas treatment process lines of the adsorption cylinders (A) and (B), and valves V2 and V3 are used for the desorption and regeneration processes of the volatile anesthetic agent from the adsorption cylinder. Operates as If the processing capacity for adsorbing the volatile anesthetic agent of the adsorbent is obtained in advance, the second series of adsorption cylinders (B) is automatically controlled by controlling the valves V1 and V4 after a certain time according to the amount of gas to be processed. You can switch to When the adsorption process line is switched to the (B) side, the adsorption cylinder (A) that has adsorbed the volatile anesthetic can be connected to the vacuum pump 10 by adjusting the valves V2 and V3, preferably almost simultaneously. .

  By opening the valve (A) side of the valve V2 and closing the valve V3, the adsorption cylinder (A) is depressurized by the vacuum pump 10, and the desorbed volatile anesthetic agent is supplied to the cooler 2 via the pipe 15. To be introduced. The volatile anesthetic is cooled by the cooler 2, liquefied or frozen, and recovered using the recovery device 8. Further, when the suction cylinder (A) is depressurized by the vacuum pump 10, a purge gas may be used. The purge gas is introduced into the adsorption cylinder (A) through the dilution gas suction line 12 and the amount of the purge gas can be controlled by adjusting the valves V2 and V3.

  The collection device 8 includes an open / close valve V5. Here, the processing apparatus of the present invention includes an unrecovered gas recovery line 13 for adsorbing and removing unrecovered volatile anesthetic corresponding to the vapor pressure at the cooling temperature. The volatile anesthetic agent corresponding to the vapor pressure is returned to the front side of the valve V1 via the unrecovered gas recovery line 13 and can be brought into contact with the adsorbent again.

  In the decomposition reactor 3, nitrous oxide is decomposed into nitrogen and oxygen and discharged. The exhaust gas is heat-exchanged with the gas introduced into the cracking reactor 3 in the heat exchanger 14 before being released to the atmosphere, and then released to the atmosphere via the nitrous oxide gas detector 7. The At this time, the nitrous oxide concentration can be detected by the nitrous oxide gas detector 7 and the reaction temperature of the decomposition reactor 3 can be controlled. In addition, the decomposition reactor 3 incorporating the nitrous oxide decomposition catalyst and the heat exchanger 14 have an integral structure, and the vertical arrangement arranged in the vertical direction reduces the size of the apparatus and reduces heat loss. Can do.

  FIG. 4 shows an example of the surplus anesthetic gas treatment apparatus of the present invention, and shows an apparatus in which a guard adsorption cylinder 16 is added to the surplus anesthetic gas treatment apparatus shown in FIG. If the installation place of a guard adsorption cylinder is between the adsorption cylinder 1 and the nitrous oxide decomposition reactor 3, there will be no restriction | limiting in particular. The apparatus shown in FIG. 3 has two adsorption cylinders in parallel, and can switch to the other adsorption cylinder before one of the adsorption cylinders breaks through, and can operate stably for a long time. By installing 16, safer driving becomes possible.

It is the schematic which shows one example of the surplus anesthetic gas processing apparatus of this invention. It is the schematic which shows one example of the surplus anesthetic gas processing apparatus of this invention. It is the schematic which shows one example of the surplus anesthetic gas processing apparatus of this invention. It is the schematic which shows one example of the surplus anesthetic gas processing apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Adsorption cylinder 2 Cooler 3 Nitrous oxide decomposition reactor 4 Flow meter 5 Dilution gas induction pump 6 Dilution gas inlet 7 Nitrous oxide gas detector 8 Volatile anesthetic recovery device 9 Cryogenic refrigerator 10 Vacuum pump 11, 12 Dilution gas suction line 13 Unrecovered gas recovery line 14 Heat exchanger 15 Volatile anesthetic recovery line 16 Guard adsorption cylinder

Claims (21)

A method for treating surplus anesthetic gas, comprising the following two steps.
(1) A surplus anesthetic gas containing a volatile anesthetic and nitrous oxide is introduced into an adsorption cylinder, and the volatile anesthetic contained in the surplus anesthetic gas is brought into contact with the adsorbent filled in the adsorption cylinder. Step of removing by adsorption (2) Step of decomposing nitrous oxide by contacting a gas containing nitrous oxide discharged from step (1) with a catalyst A method for treating surplus anesthetic gas, comprising the following two steps.
(1) Surplus anesthesia gas containing volatile anesthetic and nitrous oxide is introduced into at least one of the adsorbing cylinders connected in parallel and brought into contact with the adsorbent filled in the adsorbing cylinder. Step of desorbing volatile anesthetic contained in gas (2) Step of decomposing nitrous oxide by contacting gas containing nitrous oxide discharged from step (1) with a catalyst A method for treating surplus anesthetic gas, comprising the following three steps.
(1) Surplus anesthesia gas containing volatile anesthetic and nitrous oxide is introduced into at least one of the adsorbing cylinders connected in parallel and brought into contact with the adsorbent filled in the adsorbing cylinder. Step (2) for removing volatile anesthetic contained in gas by adsorption (2) Step for decomposing nitrous oxide by contacting gas containing nitrous oxide discharged from step (1) with a catalyst (3) Volatilization The volatile anesthetic is desorbed from the adsorbent that has adsorbed the sexual anesthetic to regenerate the adsorbent, and the desorbed volatile anesthetic is cooled and liquefied or frozen to recover the volatile anesthetic. Process   The processing method of the surplus anesthetic gas of Claim 3 which performs a process (1) and a process (3) simultaneously by switching the adsorption cylinder connected in parallel to a process (1) and a process (3) alternately.   The method for treating surplus anesthetic gas according to claim 4, wherein switching between the step (1) and the step (3) is controlled by a sequencer.   Step (3) is performed under reduced pressure, and the gas discharged from Step (3) is introduced into at least one of the adsorption cylinders connected in parallel and brought into contact with the adsorbent filled in the adsorption cylinder. The method for treating excess anesthetic gas according to any one of claims 3 to 5, wherein unrecovered volatile anesthetics contained in the gas discharged from step (3) are adsorbed and removed.   The purge gas is introduced under reduced pressure to perform step (3), and the gas discharged from step (3) is introduced into at least one of the adsorption cylinders connected in parallel, and the adsorbent filled in the adsorption cylinder The excess anesthetic gas treatment according to any one of claims 3 to 5, wherein the unrecovered volatile anesthetic contained in the gas containing the purge gas discharged from the step (3) is adsorbed and removed by contacting with the gas. Method.   The method for treating excess anesthetic gas according to any one of claims 3 to 7, wherein in step (3), the temperature at which the detached volatile anesthetic is cooled is -95 to 10 ° C.   The method for treating surplus anesthetic gas according to any one of claims 1 to 8, wherein the concentration of the volatile anesthetic contained in the surplus anesthetic gas is 0.1 to 3%.   The method for treating excess anesthetic gas according to any one of claims 1 to 9, wherein the volatile anesthetic is a fluoroether type.   Volatile anesthetics are 1,1,1-trifluoro-2-bromo-2-chloroethane, 1-chloro-2,2,2-trifluoroethyl difluoromethyl ether and / or fluoromethyl-2,2,2 The method for treating excess anesthetic gas according to claim 1, which is -trifluoro-1- (trifluoromethyl) ethyl ether.   The method for treating excess anesthetic gas according to any one of claims 1 to 11, wherein the adsorbent is at least one adsorbent selected from the group consisting of activated carbon, zeolite, silica, mesoporous silica, and alumina.   The method for treating excess anesthetic gas according to claim 12, wherein the pore diameter of the adsorbent is 5 to 100 mm.   The method for treating excess anesthetic gas according to any one of claims 1 to 13, wherein the concentration of nitrous oxide contained in the excess anesthetic gas is 3 to 70%.   The method for treating excess anesthetic gas according to any one of claims 1 to 14, wherein the catalyst for decomposing nitrous oxide is an alumina catalyst. The method for treating excess anesthetic gas according to any one of claims 1 to 15, wherein the catalyst for decomposing nitrous oxide is at least one catalyst selected from the group consisting of the following (I) to (III).
(I) Catalyst in which aluminum, magnesium and rhodium are supported on a carrier (II) Catalyst in which magnesium and rhodium are supported on an alumina carrier (III) Spinel-type crystalline composite oxide comprising at least part of aluminum and magnesium A catalyst in which rhodium is supported on a support on which is formed The method for treating excess anesthetic gas according to any one of claims 1 to 15, wherein the catalyst for decomposing nitrous oxide is at least one catalyst selected from the group consisting of the following (IV) to (VI).
(IV) at least one metal selected from the group consisting of zinc, iron and manganese, and a catalyst in which aluminum and rhodium are supported on a carrier. (V) at least one metal selected from the group consisting of zinc, iron and manganese; The spinel-type crystalline composite oxide is formed by at least a part of the catalyst (VI) aluminum in which rhodium is supported on an alumina carrier and at least one metal selected from the group consisting of zinc, iron and manganese. Catalyst with rhodium supported on the support   The decomposition temperature of nitrous oxide is 200-600 degreeC, The processing method of the excess anesthetic gas in any one of Claims 1-17.   The method for treating an excess anesthetic gas according to any one of claims 16 to 18, wherein the amount of NOx produced during the decomposition of nitrous oxide is 1 ppm or less.   20. In the step (2), heat exchange is performed between the gas discharged from the step (1) and the gas discharged from the step (2) after decomposing nitrous oxide. Treatment method of surplus anesthetic gas. The concentration of nitrous oxide contained in the gas after decomposing nitrous oxide is detected, and the decomposition temperature of nitrous oxide is controlled based on the detected concentration of nitrous oxide. Of excess anesthetic gas treatment.

Images