JP7360122B2 - Hydrogen peroxide gas generator and hydrogen peroxide gas generation method - Google Patents

Description

Application of Article 30, Paragraph 2 of the Patent Act September 12, 2018 (Held from September 12, 2018 to September 14, 2018) 59th Annual Meeting of the Atmospheric Environment Society Kyushu University Chikushi Campus 2018 November 20th (Held from November 19th, 2018 to November 20th, 2018) 2018 27th Sonochemistry Discussion Tokyo Denki University Tokyo Senju Campus 100th Anniversary Hall, Building 1 February 14th, 2019 2018 Graduation/Master's Thesis Presentation Saitama University Faculty of Engineering

The present invention relates to a hydrogen peroxide gas generation device and a hydrogen peroxide gas generation method.

In recent years, hydrogen peroxide (H ₂ O ₂ ) gas has been used instead of formaldehyde to sterilize target spaces such as clean rooms. Formaldehyde gas is considered to be harmful to the human body due to its acute toxicity and carcinogenicity. On the other hand, hydrogen peroxide (H ₂ O ₂ ) gas decomposes into oxygen and water as shown in the chemical formula 2H ₂ O ₂ → 2H ₂ O + O ₂ , and no harmful substances are generated. It is. Therefore, hydrogen peroxide gas is used to sterilize rooms such as clean rooms and small spaces such as draft chambers, isolators, and RABS (Restricted Access Barrier Systems).

Conventionally, hydrogen peroxide solution has been used to generate hydrogen peroxide gas. Hydrogen peroxide is usually commercially available as a 35 wt % aqueous solution, so when it is used for sterilization, hydrogen peroxide gas and water vapor are generated, increasing the humidity in the target room. Therefore, there is a problem in that water vapor condenses on walls and the like, corroding the structural materials of clean rooms and the like. To deal with such problems, conventional methods used special filters to remove moisture from hydrogen peroxide gas, or installed dehumidifiers with cooling coils to dehumidify the target space. . This has led to the system becoming larger and more expensive.

Furthermore, sodium percarbonate is known as a substance containing hydrogen peroxide. Sodium percarbonate is blended into detergents and the like, and dissociates into hydrogen peroxide and sodium carbonate in an aqueous solution. By heating sodium percarbonate, it is possible to eliminate hydrogen peroxide in the gas phase. However, since the hydrogen peroxide desorbed by heating is immediately decomposed into water and oxygen, hydrogen peroxide gas could not be obtained from sodium percarbonate.

JP2006-288647A

Takeshi Wada, Nobuyoshi Koga, “Kinetics and Mechanism of the Thermal Decomposition of Sodium Percarbonate: Role of the Surf ace Product Layer”, THE JOURNAL OF PHYSICAL CHEMISTRY A, 2013, pp. 1880-1889

The present invention has been proposed to solve the above problems. An object of the present invention is to provide a hydrogen peroxide gas generation device and a hydrogen peroxide gas generation method that can supply hydrogen peroxide gas with low humidity.

The inventor of the present invention noticed that sodium percarbonate in detergents turns into sodium carbonate when left for a long time. In other words, it was thought that hydrogen peroxide may have volatilized by leaving sodium percarbonate for a long time. The inventor believed that if hydrogen peroxide gas could be extracted from sodium percarbonate, it would be possible to obtain hydrogen peroxide gas with lower humidity than when hydrogen peroxide gas was generated from an aqueous hydrogen peroxide solution, and conducted extensive research. went. As a result, we have found that hydrogen peroxide gas can be obtained from sodium percarbonate by using a hydrogen peroxide gas generator with the following configuration.

(1) It has a container containing sodium percarbonate, a heating device that heats the container, a gas supply path that supplies gas to the container, and a humidifier that humidifies the gas supplied to the container. The humidified air humidified by the humidifier is vented into the container through the gas supply path.

(2) The heating device may heat the container so that the temperature of the sodium percarbonate in the container is 50°C or more and less than 100°C.

(3) The absolute humidity of the humidified air may be 2.0 g/m ³ or more and less than 16.0 g/m ³ .

(4) The sodium percarbonate may be in powder form.

Note that each of the above embodiments can also be considered as a hydrogen peroxide gas generation method.

According to the present invention, it is possible to provide a hydrogen peroxide gas generation device and a hydrogen peroxide gas generation method that can supply hydrogen peroxide gas with low humidity.

1 is a configuration diagram showing a first embodiment of a hydrogen peroxide gas generator according to the present invention. It is a flow chart showing a process of generating hydrogen peroxide gas. This is experimental data when dry air is used. (a) is a graph showing the relationship between the heating temperature of sodium percarbonate and the hydrogen peroxide concentration of hydrogen peroxide gas, and (b) is a graph showing the relationship between the heating temperature of sodium percarbonate and the hydrogen peroxide concentration. It is a graph which shows the relationship between the relative humidity of hydrogen peroxide gas, and the relative humidity of hydrogen peroxide gas. It is a graph showing the relationship between the heating temperature of sodium percarbonate and the hydrogen peroxide concentration of hydrogen peroxide gas when humidified air is used. It is a graph showing the relationship between humidified air conditions and hydrogen peroxide concentration of hydrogen peroxide gas. It is a graph showing the relationship between the shape of sodium percarbonate and the hydrogen peroxide concentration of hydrogen peroxide gas. It is a block diagram which shows other embodiment of the hydrogen peroxide gas generation apparatus based on this invention.

[First embodiment]
[1. composition]
An embodiment of a hydrogen peroxide gas generator according to a first embodiment of the present invention will be described in detail with reference to the drawings. As shown in FIG. 1, the hydrogen peroxide gas generator has a housing 1. As shown in FIG. Inside the housing 1, a container 2 filled with sodium percarbonate and a heating device 3 for heating the container 2 are provided.

(container)
Container 2 is a member that accommodates sodium percarbonate. The example in FIG. 1 shows a filling container whose hollow part is filled with sodium percarbonate. The container 2 is preferably made of a material that has high thermal conductivity and makes the temperature inside the container 2 uniform. For example, as the container 2, a cylindrical glass tube or metal tube cartridge can be used.

Although granular sodium percarbonate may be used as the sodium percarbonate contained in the container 2, it is preferable to use powdered sodium percarbonate obtained by grinding granular sodium percarbonate. By using sodium percarbonate after grinding, the efficiency of generating hydrogen peroxide gas increases. As the granular sodium percarbonate, particles having a particle size of about 100 μm to about 1.5 mm can be used. Note that a commercially available reagent may be used as is as the granular sodium percarbonate. Further, as the powdered sodium percarbonate, powder having a particle size of about 0.1 μm to several tens of μm can be used.

In the following description, a case where a cartridge is used as the container 2 will be described as an example. A gas supply path A and a hydrogen peroxide gas supply path H are connected to this cartridge. Specifically, a gas supply path A is connected to an opening at one end of the glass tube or metal tube via a tube connector. A hydrogen peroxide gas supply path H is connected to the opening at the other end of the glass tube or metal tube via a tube connector.

The cartridge is configured to be removable from the hydrogen peroxide gas generator, and is replaced after hydrogen peroxide gas is generated. Further, a configuration may be adopted in which a plurality of cartridges are installed depending on the amount of hydrogen peroxide gas generated. The diameter and length of the cartridge may be configured so that the sodium percarbonate within the cartridge is heated uniformly when heated by the heating device 3 as described below.

(heating device)
The heating device 3 is a device for heating the container 2. When the container 2 is a cartridge, a conductor can be used as the heating device 3. As the conductor for heating the cartridge, it is preferable to use a conductor with high electrical conductivity, such as an aluminum wire or a copper wire. Besides, nichrome wire or Kanthal wire may be used. The cross-sectional area and winding length of the conductor are adjusted in consideration of the resistance of the container 2 so that the cartridge can be heated to a desired temperature by the current supplied from the power supply transformer. Note that not only a linear heating element such as a conductor, but also a heater that generates heat in a planar manner may be used. That is, it is preferable to use a hot plate, an oil bath, or the like depending on the shape and material of the container 2.

The heating device 3 includes a control device (not shown). That is, a control device is connected to the conductor, and in response to a control signal from the control device, the conductor heats the container 2 so that the sodium percarbonate in the container 2 reaches a desired temperature. Specifically, it is preferable to heat the container 2 so that the temperature of the sodium percarbonate in the container 2 is 50°C or more and less than 100°C. When the heating device 3 heats the sodium percarbonate in such a temperature range, hydrogen peroxide gas is efficiently generated. Note that the actual heating temperature of the heating device 3 and the temperature of the sodium percarbonate in the container 2 differ due to the shape and material of the container 2. Therefore, the heating device 3 is a heating device capable of heating the container 2 so that the temperature of the sodium percarbonate in the container 2 is 50° C. or more and less than 100° C.

While hydrogen peroxide has a strong binding force to sodium carbonate, when heated to 50°C or higher, hydrogen peroxide decomposes while being eliminated, and when the temperature rises to 100°C or higher, it decomposes significantly. That is, below 50°C, the efficiency of hydrogen peroxide gas generation is low. Heating sodium percarbonate at higher temperatures tends to improve the efficiency of hydrogen peroxide gas generation. However, when heated above 100°C, hydrogen peroxide gas desorbed from sodium percarbonate begins to decompose into water and oxygen almost at the same time as desorption. Therefore, the generated hydrogen peroxide gas decomposes into water and humidity increases. As is clear from the experimental results described below, in particular, by setting the temperature of sodium percarbonate to 65 to 85°C, the efficiency of hydrogen peroxide gas generation can be increased without increasing humidity.

For example, if the cartridge, which is the container 2, is formed of a glass tube, the temperature of the heated cartridge is about 5 degrees higher than the temperature of the sodium percarbonate in the cartridge. Therefore, when using a glass tube, the heating device 3 is configured so that the temperature of the cartridge is 55 to 105°C. In this way, the specific temperature difference varies depending on the material of the cartridge, but after considering the difference between the temperature of the cartridge and the temperature of sodium percarbonate, it is assumed that the temperature of sodium percarbonate in the cartridge is 50°C or more and less than 100°C. You can configure it so that

(Gas supply path)
The gas supply path A is a duct that supplies gas to the container 2. One end of the gas supply path A is connected to the container 2, and the other end is connected to a gas supply system (not shown). In the hydrogen peroxide gas generator of this embodiment, humidified air is ventilated into the container 2 via the gas supply path A. Humidified air is preferably a gas with an absolute humidity of 2.0 g/m ³ or more and less than 16.0 g/m ³ . In particular, when the gas has an absolute humidity of 2.0 g/m ³ or more and 9.9 g/m ³ or less, the hydrogen peroxide gas generation efficiency becomes good. One of the reasons for supplying gas to the container 2 is to force hydrogen peroxide gas generated from sodium percarbonate toward the target space by the supplied gas.

Further, by supplying humidified air to the container 2, generation of hydrogen peroxide gas can be promoted. It is assumed that the moisture contained in humidified air affects the generation of hydrogen peroxide gas as described below. That is, when sodium percarbonate is heated, hydrogen peroxide inside the sodium percarbonate first decomposes into water. This decomposed water forms a film of water on the surface of sodium percarbonate, and hydrogen peroxide in the molecules of sodium percarbonate dissolves in the film of water. It is thought that after the hydrogen peroxide in the water film becomes saturated, the hydrogen peroxide volatilizes as hydrogen peroxide gas. Therefore, from the viewpoint of humidifying the surface of sodium percarbonate, it is considered that the introduction of humidified air contributes to promoting the generation of hydrogen peroxide gas.

The gas supply system can be configured to supply gas to the gas supply path A using a fan or a blower. When indoor air is blown into the gas supply path A using a fan or blower, it is preferable to provide a humidifier in the gas supply path A to increase the absolute humidity of the indoor air.

Furthermore, the gas supply system may include an oil mist separator for oil removal, if necessary. Furthermore, a filter for removing dust, bacteria, and organic matter may be installed. That is, in order to satisfy gas conditions necessary for a target space such as a biological clean room, it is possible to appropriately provide a dryer, a separator, a filter, etc. in the gas supply system and the gas supply path A.

The gas supply path A is provided with a pressure reducing valve a1, a check valve a2, and a flow meter a3. The pressure reducing valve a1 is a valve for reducing the pressure of the gas supplied to the gas supply path A and keeping the pressure constant after the pressure reduction. A control device (not shown) is connected to the pressure reducing valve a1, and the opening degree of the pressure reducing valve a1 is adjusted by a control signal from the control device. The pressure of the gas supplied to the container 2 is preferably 101.325 Pa as atmospheric pressure.

The check valve a2 is a valve for preventing the gas supplied to the gas supply path A from flowing backward. The check valve a2 has a structure that automatically closes when the gas supplied to the gas supply path A attempts to flow in the opposite direction. A control device (not shown) is connected to the check valve a2, and the opening degree of the check valve a2 is adjusted by a control signal from the control device. The control device closes the check valve a2 when the operation of the hydrogen peroxide gas generator ends.

Further, the flow meter a3 is a measuring device that measures the flow rate of the gas supplied to the gas supply path A. The measurement results of the flowmeter a3 are displayed so that the user of the hydrogen peroxide gas generator can visually confirm them. The flow rate of the gas may be determined in consideration of the volume of the target space, the concentration of hydrogen peroxide gas, the sterilization time, etc. The flow meter a3 may be provided with a control device, and when the user inputs the volume of the target space, the concentration of hydrogen peroxide gas, and the sterilization time into the control device, the flow rate of the gas may be automatically determined. The flow rate of the gas supplied to the gas supply path A may be determined by the user checking the value of the flow meter and manually adjusting the flow rate of the gas supply system. However, the flow rate can also be adjusted to a desired flow rate by providing a valve in the gas supply path A and adjusting the opening degree of this valve using a control device.

(Hydrogen peroxide gas supply path)
The hydrogen peroxide gas supply path H is a duct that supplies hydrogen peroxide gas to the target space S. The end of the hydrogen peroxide gas supply path H opposite to the end connected to the container 2 is installed within the target space. The gas supplied to the container 2 via the gas supply path A sweeps away the hydrogen peroxide gas immediately after desorption in the container 2, and is supplied together with the hydrogen peroxide gas to the target space via the hydrogen peroxide gas supply path H. be done.

In the above configuration, a temperature sensor may be provided near the container 2 or the conductor, and the hydrogen peroxide gas supply path H. The temperature sensor is connected to a control device, and the control device preferably controls the heating device so that the temperature of the container 2 and the hydrogen peroxide gas supply path H does not exceed a predetermined temperature. By controlling the structure through which hydrogen peroxide gas passes to a temperature below a predetermined temperature, hydrogen peroxide gas is prevented from being decomposed into water and oxygen.

[2. Hydrogen peroxide gas generation process]
As shown in FIG. 2, the hydrogen peroxide gas generator having the above configuration generates hydrogen peroxide gas through the following steps.
(1) Heating process of container 2 (2) Gas supply process to container 2

(Heating process)
In the heating step, the heating device 3 heats the cartridge installed in the casing 1 of the hydrogen peroxide gas generator. That is, in response to a control signal from the control device, the heating device 3 heats the cartridge so that the temperature of the sodium percarbonate filled in the cartridge is 50° C. or more and less than 100° C. By heating the cartridge, the surface of the sodium percarbonate is heated and hydrogen peroxide gas is generated. At the same time as this heating step is started, the gas supply step is also started.

(Gas supply process)
In the gas supply step, humidified air is supplied to the cartridge. That is, the pressure reducing valve a1 and the check valve a2 are opened according to a control signal from the control device, and humidified air is supplied to the gas supply path A. The absolute humidity of the humidified air is 2.0 g/m ³ or more and less than 16.0 g/m ³ . The humidified air supplied to the gas supply path A is sent to the cartridge via a flow meter.

The gas supplied into the cartridge advances toward the hydrogen peroxide gas supply path H side. In this process, the humidified air humidifies the surface of the sodium percarbonate to promote the generation of hydrogen peroxide gas, and also sweeps away the hydrogen peroxide gas generated from the sodium percarbonate. That is, hydrogen peroxide gas generated from sodium percarbonate is flowed toward the hydrogen peroxide gas supply path H side by gas at any time.

The gas containing hydrogen peroxide gas reaches the outlet side of the cartridge and flows directly into the hydrogen peroxide gas supply path H. The hydrogen peroxide gas is then supplied to the target space via the hydrogen peroxide gas supply path H. Heating the cartridge and supplying humidified air to the cartridge is performed for a predetermined period of time to provide sufficient hydrogen peroxide gas to sterilize the target space.

[3. experiment]
Hereinafter, hydrogen peroxide gas generated by the hydrogen peroxide gas generator of this embodiment was verified. In each experiment, unless otherwise specified, hydrogen peroxide gas was generated and measured using the same experimental equipment and conditions.
(experimental equipment)
Generation and measurement of hydrogen peroxide gas were performed using the following equipment and procedures. That is, 2 g of granular sodium percarbonate was placed in a glass reactor with a volume of 500 mL and fixed in a water bath. The water bath temperature was set and gas was bubbled through the sample at 0.5 L/min for 1 hour while maintaining the set temperature. Room temperature air was used as the gas. A thermohygrometer and a hydrogen peroxide detector were installed to measure the temperature, humidity, and hydrogen peroxide concentration of the gas discharged from the glass reactor.

The hydrogen peroxide detector used in the experiment was capable of detecting hydrogen peroxide in the range of 0.0 to 300 ppm. The hydrogen peroxide detector had a built-in pump, and this pump was configured to suck gas at a rate of 0.67 L/min. Since gas is supplied to the reactor at a rate of 0.5 L/min, the gas discharged from the reactor is diluted by two times using the supplied gas just before the hydrogen peroxide detector, and the flow rate is increased. The hydrogen peroxide gas concentration was measured after setting the pressure to 1.0 L/min.

When humidifying gas, the air to be vented was passed through a container containing water and a porous polytetrafluoroethylene (PTFE) tube. A PTFE tube is a tube that allows only gas to pass through, and when the surrounding area is filled with water, the humidity of the air can be adjusted by adjusting the tube length, the flow rate of air passing through the inside, the amount of water filling the surrounding area, etc. By changing these conditions, humidified air with desired humidity was obtained.

(Heating temperature of sodium percarbonate)
(1) Experiment using dry air First, an experiment was conducted using dry air to verify the relationship between the heating temperature of sodium percarbonate and the concentration of generated hydrogen peroxide. This experiment was conducted using 2 g of sodium percarbonate for each sample, which had been preheated at 80° C. for 1 hour. The heating temperatures for sodium percarbonate were 95, 105, 110, 115, 120, and 125°C. In the experiment, sodium percarbonate was placed in a glass reactor and heated in an oil bath. Therefore, the sodium percarbonate was heated to the above temperature by setting the oil bath temperature to 100, 110, 115, 120, 125 and 130° C. and heating the reactor to the same temperature as the oil bath temperature. Further, ventilation was performed using dry air, and compressed air at a temperature of 25 degrees or less was used.

Hydrogen peroxide concentration and humidity were measured for each sample for 60 minutes. In addition, as a comparison, the hydrogen peroxide concentration and humidity were measured when hydrogen peroxide solution was bubbled.

The results of measuring the hydrogen peroxide concentration for each sample are shown in FIG. 3(a). As mentioned above, since the hydrogen peroxide concentration was measured after diluting the gas twice, FIG. 3(a) shows the concentration after correction. Moreover, each temperature indicates the oil bath temperature of the reactor. As is clear from FIG. 3(a), when the oil bath temperature becomes 100° C., that is, the sodium percarbonate temperature becomes 95° C. or higher, hydrogen peroxide gradually begins to be desorbed from the sodium percarbonate.

The results of measuring relative humidity for each sample are shown in FIG. 3(b). As is clear from FIG. 3(b), the humidity of the hydrogen peroxide gas generated by bubbling of the hydrogen peroxide solution reached 60% 15 minutes after the start of heating and gradually rose. If the relative humidity of the hydrogen peroxide gas exceeds 60%, it is undesirable because there is a high possibility that dew condensation will occur on the walls of the target space and the structural materials of the target space will corrode. On the other hand, when sodium percarbonate is heated, almost no humidity is generated when the temperature of sodium percarbonate is 95°C. However, it was found that when the temperature of sodium percarbonate exceeds 105° C., the humidity increases, although the humidity is low, below 60%. From the results of this experiment, it was found that when the temperature of sodium percarbonate becomes 100° C. or higher, humidity is generated due to the sodium percarbonate.

(2) Experiment using humidified air Next, we set the temperature of sodium percarbonate to less than 100°C, used humidified air, and further verified the relationship between the heating temperature of sodium percarbonate and the concentration of hydrogen peroxide gas generated. We conducted an experiment. Granular sodium percarbonate was used at 2 g in each sample. The heating temperatures for sodium percarbonate were 45, 55, 65, 75, and 85°C. In the experiment, sodium percarbonate was placed in a glass reactor and heated in a water bath. Therefore, the reactor was heated with water bath temperatures of 50, 60, 70, 80, and 90°C. Note that the water bath temperature includes an error of ±3°C. Further, ventilation was performed with humidified air, and humidified air with an absolute humidity of 9.9 g/m ³ (relative humidity 50%) was used.

FIG. 4 shows the results of measuring the hydrogen peroxide concentration for each sample. As mentioned above, since the hydrogen peroxide concentration was measured after diluting the gas twice, FIG. 4 shows the concentration after correction. Moreover, each temperature indicates the water bath temperature of the reactor. As is clear from FIG. 4, when the sodium percarbonate temperature becomes 45° C. or higher, hydrogen peroxide gradually begins to be desorbed from the sodium percarbonate.

Furthermore, when the temperature of sodium percarbonate was 50°C or higher, and the water bath temperature was 60°C to 90°C, at which sodium percarbonate was considered to have decomposed, the hydrogen peroxide concentration increased and good results were obtained. Although the water bath temperature increased by several ppm until the water bath temperature reached 70°C, it was confirmed that the hydrogen peroxide gas concentration increased significantly at 80°C, and the gas concentration reached 37 ppm after 60 minutes. At 90° C., the hydrogen peroxide gas concentration further increased, and the gas concentration after 60 minutes was 49 ppm. In this way, it was confirmed that when humidified air was used, the concentration continued to be maintained above a certain level even 60 minutes after the start of the reaction. Note that at any temperature, the relative humidity of hydrogen peroxide gas did not vary from the initial setting humidity of 50%. That is, it was confirmed that when sodium percarbonate was heated at 45° C. or higher and lower than 100° C., the humidity of hydrogen peroxide gas did not increase.

(humidification conditions of humidified air)
Next, an experiment was conducted in which the heating temperature of sodium percarbonate was set at 75° C., and the conditions of the humidified air introduced were changed to generate hydrogen peroxide gas. Granular sodium percarbonate was used at 2 g in each sample. The heating temperature of sodium percarbonate was 75°C. In the experiment, sodium percarbonate was placed in a glass reactor and heated in a water bath. Therefore, the reactor was heated with a water bath temperature of 80°C. In addition, ventilation was performed with humidified air, with absolute humidity of 0 g/m ³ (relative humidity 0%), absolute humidity 2.0 g/m ³ (relative humidity 10%), and absolute humidity 9.9 g/m ³ (relative humidity 50%). ), and humidified air with an absolute humidity of 16.0/m ³ (relative humidity 80%) was used.

FIG. 5 shows the results of measuring the hydrogen peroxide concentration for each sample. As mentioned above, since the hydrogen peroxide concentration was measured after diluting the gas twice, FIG. 5 shows the concentration after correction. Moreover, each humidity is a value obtained by measuring the relative humidity inside the reactor. As is clear from FIG. 5, after 60 minutes, generation of hydrogen peroxide gas was confirmed to be about 8 ppm when the relative humidity was 0%, and about 15 ppm when the relative humidity was 10%. Furthermore, in the case of a higher relative humidity of 50%, the concentration of hydrogen peroxide gas generated was about 35 ppm. At a relative humidity of 0 to 50 wt%, hydrogen peroxide gas after 60 minutes increased as the humidity increased.

On the other hand, when the relative humidity was 80%, the hydrogen peroxide gas concentration decreased to 20 ppm compared to when the relative humidity was 50%. Further, 60 minutes after the start of the reaction, the concentration of generated hydrogen peroxide gas began to decrease. From the above, it was found that water affects the generation of hydrogen peroxide gas. It was confirmed that humidification promotes the generation of hydrogen peroxide gas, but humidification at an absolute humidity of 16.0/m ³ or more is excessive and suppresses the generation of hydrogen peroxide gas.

(grinding of sample)
The hydrogen peroxide concentration was measured when granular sodium percarbonate was ground into powder. This experiment used 2g of sodium percarbonate in each sample, with one using granular sodium percarbonate. The other sodium percarbonate was ground manually using a mortar for 1 minute. The heating temperature of sodium percarbonate was 75°C. In the experiment, sodium percarbonate was placed in a glass reactor and heated in a water bath. Therefore, the water bath temperature was set to 80°C. The gas that was vented was humidified air with an absolute humidity of 9.9 g/m ³ (relative humidity 50%).

FIG. 6 shows the results of measuring hydrogen peroxide concentrations for granular sodium percarbonate and powdered sodium percarbonate. As is clear from FIG. 6, when powdered sodium percarbonate was used, the hydrogen peroxide concentration was improved compared to granular sodium percarbonate. This result is thought to be due to the fact that, in the case of powdered sodium percarbonate, the contact area with the bottom of the reactor increased, making it easier for heat to be transferred to the sodium percarbonate, thereby accelerating the process of hydrogen peroxide gas generation. Furthermore, no increase in humidity was detected in the hydrogen peroxide gas generated.

[4. Effect]
The effects of the hydrogen peroxide gas generator of this embodiment as described above are as follows.
(1) It has a container 2 containing sodium percarbonate, a heating device 3 that heats the container 2, and a gas supply path A that supplies gas to the container 2, and humidified air is supplied through the gas supply path A. Vent into container 2.

By heating the container 2 containing sodium percarbonate, hydrogen peroxide can be desorbed from the sodium percarbonate. Moreover, by ventilating humidified air into the container 2, hydrogen peroxide gas can be taken out while promoting the generation of hydrogen peroxide gas. As described above, it is possible to obtain hydrogen peroxide gas with lower humidity than when hydrogen peroxide gas is generated from an aqueous hydrogen peroxide solution. Hydrogen peroxide aqueous solution is dangerous to transport, but sodium percarbonate is solid and highly safe, so it can be transported at low cost.

(2) The heating device 3 heats the container so that the temperature of the sodium percarbonate in the container 2 is greater than or equal to 50°C and less than 100°C.

By setting the heating temperature of sodium percarbonate to 50°C or higher and lower than 100°C, it is possible to generate low-humidity hydrogen peroxide gas with a relative humidity of 60% or less while maintaining hydrogen peroxide gas generation efficiency. Become.

(3) The absolute humidity of the humidified air is 2.0 g/m ³ or more and less than 16.0 g/m ³ .

By supplying humidified air with an absolute humidity of 2.0 g/m ³ or more and less than 16.0 g/m ³ to the container 2, it is possible to promote the generation of hydrogen peroxide gas. Furthermore, the resulting hydrogen peroxide gas can have low humidity.

(4) Sodium percarbonate is in powder form.

By using powdered sodium percarbonate, it becomes possible to obtain hydrogen peroxide gas with a higher concentration.

[Other embodiments]
In the above embodiment, the hydrogen peroxide gas generator is described as a device that generates hydrogen peroxide gas that sterilizes walls and surfaces of devices installed in the target space, such as a biological clean room. . However, the hydrogen peroxide gas generated by the hydrogen peroxide gas generator may be used for purposes other than sterilization. For example, the hydrogen peroxide gas generated by the hydrogen peroxide gas generator of the above embodiment can be used for air purification, decomposition of pollutants, and the like.

(About the shape of sodium percarbonate)
When powdered sodium percarbonate is used, it is preferably filled into the container 2 together with a fibrous material, for example. Since the fibrous material includes voids in its internal structure, even when finely powdered sodium percarbonate is used, voids that serve as gas passages are likely to be formed between adjacent sodium percarbonate. As the fibrous material, glass fiber, glass wool, nonwoven fabric, etc. can be used.

(About the cartridge configuration)
In the above embodiments, the cartridge is a cylindrical glass or metal tube, and the hollow part is filled with sodium percarbonate. However, as shown in FIG. 7, the cartridge may be composed of an outer tube 2a made of a glass tube or a metal tube, and an inner tube 2b housed inside the outer tube 2a. Sodium percarbonate is filled into the space between the outer cylinder 2a and the inner cylinder 2b. Here, the inner cylinder 2b has a metal mesh structure. Therefore, by supplying gas to the cylindrical space formed by the inner peripheral surface of the inner cylinder 2b, it is possible to ventilate the sodium percarbonate. A diffusion dryer may be used as an example of such a cartridge.

Furthermore, in order to improve the ventilation efficiency to the sodium percarbonate, the gas supply port of the cartridge may be provided with an angle to supply air toward the inner circumferential surface of the outer cylinder 2a. That is, a mechanism for supplying air so that the gas swirls inside the cartridge can be provided.

Further, the sodium percarbonate container 2 does not necessarily have to be a cartridge. For example, sodium percarbonate may be placed on a glass plate such as a petri dish. In this case, the bottom surface of the petri dish is heated and humidified air is supplied from the side of the petri dish. Alternatively, a bottle-shaped glass container may be used, two openings may be provided in the lid of the glass container, humidified air may be supplied from one, and hydrogen peroxide gas may be recovered from the other.

A Gas supply path a1 Pressure reducing valve a2 Check valve a3 Flow meter H Hydrogen peroxide gas supply path 1 Housing 2 Container 2a Outer cylinder 2b Inner cylinder 3 Heating device

Claims (7)

a container containing sodium percarbonate;
a heating device that heats the container;
a gas supply path that supplies gas to the container;
a humidifier that humidifies the gas supplied to the container,
A hydrogen peroxide gas generation device that ventilates humidified air humidified by the humidifier into the container via the gas supply path. The hydrogen peroxide gas generator according to claim 1, wherein the heating device heats the container so that the temperature of the sodium percarbonate in the container is 50°C or more and less than 100°C. The hydrogen peroxide gas generator according to claim 1 or 2, wherein the humidified air has an absolute humidity of 2.0 g/m ³ or more and less than 16.0 g/m ³ . The hydrogen peroxide gas generator according to any one of claims 1 to 3, wherein the sodium percarbonate is in powder form. a heating step of heating sodium percarbonate;
A method for generating hydrogen peroxide gas, comprising the step of supplying humidified air with increased absolute humidity to the heated sodium percarbonate. 6. The method for generating hydrogen peroxide gas according to claim 5, wherein the heating step is a step of heating the sodium percarbonate so that the temperature of the sodium percarbonate becomes 50° C. or more and less than 100° C. The method for generating hydrogen peroxide gas according to claim 5 or 6, wherein the humidified air has an absolute humidity of 2.0 g/m ³ or more and less than 16.0 g/m ³ .

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