JP5893939B2 - Ozone water generation apparatus and ozone water generation method - Google Patents

Description

The present invention relates to an ozone water generating apparatus and the ozone water producing how.

  It is desired that ozone water exerts the effect of substance peeling due to oxidation of the target surface more effectively for the purpose of use represented by sterilization, cleaning, deodorization, decontamination of radioactive substances, and the like. In order to enhance the effect of ozone water, it is required to make ozone water reach a higher dissolved ozone concentration. In technical fields where it is necessary to sprinkle a large amount of ozone water, it is desirable to store a predetermined amount of ozone water in a tank. It was difficult to maintain stable and store at high concentration.

  It is known that ozone molecules in ozone water are hardly soluble gases and exist in the state of ozone gas bubbles or dispersed ozone molecules. In any case, it is extremely important as an ozone water generation technology to suppress degassing from the water due to ascent and to suppress as much as possible the self-decomposition phenomenon that returns to oxygen, which is the original form prior to ozone denaturation. is there.

  Conventionally, in the field of precision equipment cleaning that should be highly clean and avoid contamination, such as semiconductor and liquid crystal panel manufacturing, the pure oxygen (purity of 99.9% or more) or the specification of the ozonizer is less than 1% of the pure oxygen. An ozone water generation method is known in which an appropriate amount of pure nitrogen gas is added, supplied to an ozonizer, discharged to generate ozone gas, and then the ozone gas is mixed with water to generate. However, in this method, pure oxygen becomes a cylinder or liquid oxygen, which is expensive and low in economic efficiency, and the range of application is limited in applications where large quantities are to be produced. In fact, only a small capacity of about 20 liters per minute as the amount of ozone water produced can be found in actual devices.

  On the other hand, a method using an oxygen concentrator represented by a PSA (Pressure Swing Adsorption) type is known as a method suitable for mass production at a low cost. In the PSA oxygen concentrator, a granular catalyst containing zeolite or the like as a main raw material is filled in a container communicating from upstream to downstream, and raw air (atmosphere) is passed through the catalyst layer to bring it into contact with the air. It has a structure that continuously adsorbs nitrogen. First, nitrogen is separated from air by a PSA type oxygen concentrator to produce concentrated oxygen gas (usually 90% to 95% concentration), which is supplied to an ozonizer installed downstream and discharged by the ozonizer to generate ozone gas. Next, the production | generation method which mixes and dissolves in raw | natural water and makes it ozone water is generally known. If this method is used, it can be applied to a wide range of uses, and the production cost of ozone water can be remarkably suppressed.

  The effect of removing carbon dioxide (carbon dioxide gas) as an ozone water generation technology using a PSA type oxygen concentrator has never been recognized. Therefore, a catalyst such as zeolite incorporated in the PSA oxygen concentrator has no carbon dioxide. There is substantially no gas removal function. Therefore. In the concentrated oxygen gas generated by the concentration, carbon dioxide gas remains at a concentration that is the same as the concentration in the raw material air before being concentrated, and is mixed with the raw material water together with the ozone gas and dissolved in the ozone water. Will be.

  On the other hand, instead of removing the carbon dioxide gas as shown in the present invention, on the contrary, many methods have been proposed in the past for supplying and adding the carbon dioxide gas and for adding the carbon dioxide gas during the supply of the ozone water. It was. These carbon dioxide addition methods pay attention only to the point that the pH of the ozone water can be maintained acidic by dissolving the carbon dioxide gas, so that the self-decomposition of the ozone molecule itself will be suppressed, and the concentration of the ozone water should be increased and maintained. Keep in mind. However, it has not been recognized that these carbon dioxide addition methods cause a significant decrease in the ozone concentration due to another phenomenon that occurs due to the presence of carbon dioxide.

JP 2006-102745 A JP 2007-222714 A Patent No. 3734207 JP 2008-155186 A Japanese Patent Laid-Open No. 5-305288 JP 2007-325981 A JP 2000-262874 A JP 2010-155754 A JP 2002-85047 A JP 2011-45298 A JP-A-11-347336

  The present invention is a method for generating ozone water that is economically and practically excellent in mass production using PSA, and is capable of generating extremely high concentrations of dissolved ozone, reaching high concentrations, and maintaining remarkable concentrations as well. Provided are an ozone water generating apparatus and a generating method for generating special stabilized ozone water having both characteristics.

The present invention includes a PSA (Pressure Swing Adsorption) type oxygen concentrator for generating concentrated oxygen gas by adsorbing and separating nitrogen gas from the air, for example, by an adsorption action by a catalyst mainly composed of zeolite, and the concentrated oxygen gas by discharge. An ozone gas generator that converts ozone gas into ozone gas, and a gas-liquid mixing device that generates ozone water by dissolving the ozone gas in raw material water, the front stage or the rear stage of the PSA oxygen concentrator And a carbon dioxide gas removing device that includes a carbon dioxide adsorption catalyst mainly composed of soda lime and removes carbon dioxide from the air or the concentrated oxygen gas .

In this case, it is preferable to provide a humidification mechanism or a hydration mechanism for supplying moisture to the soda lime of the carbon dioxide gas removing device and maintaining the carbon dioxide adsorption effect.

The present invention removes carbon dioxide gas from the air by using an adsorbent mainly composed of soda lime, then dehumidifies the air from which the carbon dioxide gas has been removed, and then adsorbs and separates nitrogen gas from the air by an adsorption action. The nitrogen gas is separated from the air by a PSA type oxygen concentrator that generates concentrated oxygen gas to generate concentrated oxygen gas, and then the concentrated oxygen gas is changed to ozone gas by discharge , and then the ozone gas is submerged in water. It is also a method for generating ozone water, wherein the step of dissolving in water is continuously performed .

  According to the present invention, special ozone water that can reach a high dissolved ozone concentration and has a surprisingly stable performance that can be stored in large quantities can be generated at a very low cost. It can be used in a wide range of technical and industrial fields.

The system block diagram which shows 1st Embodiment of the ozone water generating apparatus of this invention The system block diagram which shows 2nd Embodiment of the ozone water generating apparatus of this invention. The graph which shows the change of the ozone density | concentration with the arrival density | concentration of ozone of the ozone water produced | generated using the apparatus of embodiment of this invention, and time passage A graph showing the concentration of ozone in ozone water generated using a device that does not remove carbon dioxide from the air and the change in ozone concentration over time

(Background of the invention)
In general, ozone water is safer than ozone gas, which is harmful to human health by breathing, but the half-life of dissolved ozone concentration at room temperature and atmospheric pressure is 1 minute or several minutes. It is recognized that it is difficult to use because it is extremely short and unstable. There are many factors in the physical properties of ozone, which is a factor that leads to a decrease in the dissolved ozone concentration. First, as a representative point, ozone is hardly soluble in water and does not dissolve in water like oxygen that forms hydrogen bonds. Therefore, even if ozone gas is dissolved in water, once dissolved ozone gas quickly rises to the liquid surface and is released from the ozone water, that is, the dissolved ozone concentration decreases.

  In this regard, in order to improve the concentration stability, the inventor refines ozone bubbles, which are hardly soluble in water, and diffuses them in a form in which fine bubbles and molecules are dispersed so as not to receive buoyancy. The technology is proposed. According to these techniques, it is possible to disperse and hold in the water in the form of ultrafine bubbles that are almost unaffected by buoyancy, or in the form of ozone gas molecules with a high density that changes the hydrogen bond energy. As a result, it is possible to increase the ozone concentration so as to be noticeable by infrared spectroscopic analysis and to increase the ozone concentration so high that the properties of water are changed, and to maintain the ozone concentration stably. That is, with these methods, the degassing phenomenon of ozone and ozone bubbles from water can be effectively suppressed.

  However, apart from the viewpoint of improving the stability in which ozone gas is not degassed from the water, it is necessary to improve the technique for generating ozone water from the viewpoint of easily disappearing by reacting with all organic substances that come into contact with ozone. From this point of view, the idea that ozone is particularly easy to react, and the ozone consumption substance (called ozone scavenger) with a high rate of disappearance and return to oxygen is suppressed as low as possible to maintain the ozone water concentration, This improvement is the subject of the present invention. If the generation of a substance that consumes ozone can be suppressed in the generation of ozone water, it is possible to generate ozone water with higher concentration and more stability.

  Under the above consideration, the inventor has not paid attention to anyone, but assuming that carbon dioxide gas affects the concentration of ozone water, the PSA (Pressure Swing Adsorption) type oxygen concentrator is installed. The test used was carried out. As a result, when carbon dioxide gas is removed, it is understood that a surprisingly clear effect is produced compared with the case where carbon dioxide gas is not removed. In addition, the mechanism is studied, and the residual carbon dioxide gas generates an ozone scavenger. Ascertaining the difference between the actual situation and the absence of an ozone scavenger, the effectiveness of the present invention has been elucidated.

  There are various causes for the decrease in ozone water concentration, such as decomposition due to temperature increase indicated by Henry's constant, decomposition reaction due to ultraviolet irradiation, and maintained hydraulic environment, but this is not explained here. Further, in an ozone water generating apparatus that employs a PSA type oxygen concentrating apparatus, a very small amount of dust is naturally generated because it is generated in the process, but the raw water is so-called ultrapure water (the most common index, 25 (Theoretical value at 18.degree. C. having an electrical resistivity of 18.24 MΩ · cm) is not suitably used.

  Conventionally, a PSA (Pressure Swing Adsorption) type oxygen concentrator is often used to generate concentrated oxygen gas used for generating ozone. The PSA type oxygen concentrator is also called an adsorption type (adsorption type) oxygen concentrator. This device uses a catalyst such as zeolite that has the function of adsorbing nitrogen in the device, and repeatedly pressurizes and depressurizes the container in which the catalyst is placed, thereby separating oxygen and nitrogen in the air. It is intended for devices that are generated by the playing method. The PSA oxygen concentrator is not limited as long as it uses a catalyst containing zeolite as described above, although there are various types of catalyst containers.

  The inventor has continued to develop ozone water generation technology using this PSA type oxygen concentrator, and has obtained certain effects by making improvements such as finer bubbles and dispersion with ozone molecules as described above. However, even if the ozone water generation process is continuously operated after the dissolved ozone concentration reaches the maximum value, the problem that the concentration is unclear cannot be solved.

  Therefore, the inventor achieves a higher dissolved ozone concentration and maintains a high dissolved ozone concentration even when stored, that is, generates a large amount of high-concentration ozone water that exhibits a stronger effect and a large amount thereof. We intensively studied to achieve the generation technology.

  As shown in the related patent, according to the technical information of the disclosed third party, carbon dioxide gas (carbon dioxide gas) is added to ozone water for the purpose of suppressing ozone self-decomposition, and pH (hydrogen ion concentration index) ) Has been proposed to be effective on the acidic side (Patent Document 2).

  On the other hand, the inventor has not only an effect that carbon dioxide gas is effective, but also an idea that it may have an opposite effect, that is, an action that promotes the decomposition of ozone. Got. Therefore, as a result of investigating an effective material for removing carbon dioxide, the inventor obtained a catalyst mainly composed of soda lime and tried it by incorporating it into a test apparatus. The following items were taken into consideration in the study.

  In general, it is said that carbon dioxide of about 380 to 440 ppm is contained in the atmosphere, although there are differences depending on the region. Carbon dioxide is much more soluble in water than other constituent gases in air.

  There was no exception in the PSA type oxygen concentrator, and it was thought that carbon dioxide gas was dissolved in ozone water at the same ratio as in the air without having the function of removing carbon dioxide gas.

  The following technical background was considered as a basic recognition in the invention.

  1) The water structure is constantly moving with water molecules at a certain distance, but there is a space between the water molecules to dissolve the gas. However, the amount of gas that can be dissolved in the space under a certain condition is determined, that is, the saturation concentration differs depending on the type of gas. In addition, in any gas, as long as the space in which the gas can be dissolved in the water is full, other gas cannot enter unless it is replaced by some action.

  2) Ozone is prone to self-decomposition under alkaline conditions and easily returns to oxygen, and under acidic conditions, self-decomposition is suppressed and ozone is easily maintained.

3) Carbon dioxide gas is first dissolved in water as carbonic acid (H ₂ CO ₃ ), then dissolved as bicarbonate ions (HCO ₃ ⁻ ), and further dissolved as carbonate ions (CO ₃ ²⁻ ). Stay underwater. The pH of water changes with each state of such carbon dioxide gas. On the contrary, the presence state of carbon dioxide gas supplied in water and in contact with water varies depending on the pH of the water.

  Taking into account the properties and interrelationships of various substances as described above, and comparison conditions, the inventor has repeatedly demonstrated that it is extremely effective to remove carbon dioxide from the air, and to improve the efficiency of ozone water generation technology. And clarified that the stability of the generated ozone water itself can be greatly improved, and succeeded in the invention. In addition, the mechanism estimated as a reason which produces the said effect is mentioned later.

  This technology uses PSA type oxygen concentrator to the last and produces water other than ultrapure water (water that does not contain impurities to the extent that it has an electrical resistivity of 18.24 MΩ · cm or more at 25 ° C.) as raw water. This is ozone water generation technology. Ozone water used for cleaning in the field of manufacturing semiconductors and precision equipment uses pure water or ultrapure water as raw water. Further, when generating ozone gas, a mechanism is used in which less than 1% nitrogen gas is mixed with 100% pure oxygen or 99% or more pure oxygen and supplied to an ozonizer, and ozone gas is generated by discharge. However, since this method requires expensive and frequent cylinder replacement, it is not suitable for applications in a wide range of technical fields and industrial fields where a large amount of ozone water is desired to be generated and used.

  The use of electrolysis in the course of ozone water generation can be considered excluded from the application of the present invention. The method using electrolysis is a general method in which dissolved oxygen in water is changed to ozone on the anode side by discharge to an electrode disposed in water. However, in the electrolysis method, it is essential that some electrolyte necessary for energization is contained in water, and there are differences in the substances generated by the electrolyte, but there are 20 types of peroxides such as chlorine and chloride ions in addition to ozone. It may occur at the same time, and there is a risk of deteriorating the value for the purpose of use of the function of ozone water that is not persistent. However, when such a concern is not a problem or when a method that enables removal of by-product substances is used in combination, the ozone water concentration is higher and more stable. It can be adopted as a method for the purpose. Therefore, the use of electrolysis in the process of the present invention is not actively excluded.

  Next, an embodiment of the present invention obtained through the above examination will be described in detail.

(First embodiment)
FIG. 1 is a system configuration diagram showing a first embodiment of an ozone water generator of the present invention. Basically, the present invention is directed to ozone water generation by gas-liquid mixing. Similarly, an ozone water generating apparatus using the PSA type oxygen concentrator as a means for supplying a raw material gas (concentrated oxygen gas converted into ozone gas by discharge) is an object.

  The ozone water generation device of this embodiment includes an ozone gas generation unit 100, an ozone gas supply path 24, an ejector (gas-liquid mixing device) 14, and an ozone water generation circulation line 200. The ozone gas generation unit 100 includes a carbon dioxide removal device 1, a filter 2, a carbon dioxide concentration sensor 3, a PSA type oxygen concentrator (nitrogen separation mechanism) 28, an oxygen gas sensor 27, and an ozonizer (ozone generator) 7. And a backflow prevention valve 8. The ozone water generation circulation line 200 includes an undissolved surplus ozone gas decomposing device 12, a mixed ozone gas undissolved bubble separation tank 13, a chiller 17, a dissolved ozone concentration meter 18, a water temperature meter 19, and a cooling water circulation pump 20. An ozone water generating circulation pump 21, a storage tank 22, and an ozone water feeding discharge pump 23 are provided.

  Next, the outline | summary of the ozone water production | generation circulation line 200 is demonstrated. Tap water 16 as raw water serving as a raw material for ozone water is put into the storage tank 22. Instead of tap water, ground water or the like may be used in some cases other than pure water. In the present embodiment, water other than ultrapure water having an electrical resistivity of 18.24 MΩ · cm or more is targeted. After the raw water is supplied to a storage tank (actual capacity 200 L in this example), the water in the storage tank 22 is circulated by the cooling water circulation pump 20 and is cooled and maintained by the chiller 17 disposed in the circulation system. Basically, the water temperature tends to rise due to the heat of operation of the cooling pump, but it can be cooled and maintained at a water temperature of 5 ° C. or less by cooling with the chiller 17. Further, a dissolved ozone concentration meter 18 and a water temperature meter 19 are arranged upstream of the chiller 17 in the chiller circulation system.

  The ejector 14 is a part that performs gas-liquid mixing, and raw water is drawn from the storage tank 22 by the circulation pump 21 for ozone water generation. The ozone water generation circulation pump 21 discharges raw water (gas generation becomes ozone water when generated) for gas-liquid mixing at a water volume of 45 L / min and a water pressure of 0.35 MPa, and supplies it to the ejector 14. The water that has passed through the ejector 14 passes through the orifice portion of the ejector 14 with a high-speed water flow, generates a negative pressure due to the flow velocity of water downstream of the orifice portion, takes in ozone gas by vacuum suction, and generates cavitation. Mix water and ozone gas vigorously. Thereafter, water and ozone water formed by mixing the raw material water and ozone gas are allowed to flow into the downstream mixed ozone gas undissolved bubble separation tank 13 together with bubbles.

  The gas and water (or ozone water) sent to the mixed ozone gas undissolved bubble separation tank 13 are separated into a liquid and a gas by a separation device or the like. As a result, surplus ozone gas bubbles floating in the mixed ozone gas undissolved bubble separation tank 13 are separated and sent from above to the undissolved surplus ozone gas decomposing apparatus 12 including the ozone decomposition catalyst, and the ozone is decomposed and harmless exhaust gas. It is decomposed into gas (oxygen gas after ozone decomposition) 15 and released into the atmosphere.

  The water mixed with the ozone gas flows through the circulation system path composed of the ejector 14 and the ozone water generation / circulation line 200, and returns to the storage tank 22 in a round. By repeating this circulation, the water in the storage tank 22 is sequentially changed. It becomes high concentration ozone water. In the storage tank 22, surplus ozone gas is sent to the undissolved surplus ozone gas decomposing apparatus 12, and is changed into harmless oxygen gas.

  Next, in the present embodiment, an ozone gas generation unit (ozone gas supply line) 100 that supplies ozone gas to the ejector 14 will be described.

  As described above, in the ejector 14, the circulating water passes through the orifice at a high speed. However, since this water flows according to the law of inertia, the volume can be strongly expanded in the flow path that radially expands downstream from the orifice. As a result, a stronger negative pressure is generated, and a state close to a vacuum is generated near the orifice and the vicinity in the downstream. Due to the action of the negative pressure, the ozone gas generated by the discharge of the ozonizer 7 in the ozone gas generation unit 100 is supplied to the ejector 14 via the ozone gas supply path 24. Accordingly, ozone gas and water (or ozone water) are vigorously mixed into the ozone water in the vicinity of the orifice and its vicinity in the downstream. A backflow prevention valve 8 is arranged in the path between the ozonizer 7 and the ejector 14 in order to prevent water from flowing back and flowing into the ozonizer 7 when the apparatus is stopped.

  In the present embodiment, in the ozone gas generation unit 100, the carbon dioxide removal device 1, the filter 2, the carbon dioxide concentration sensor 3, and the PSA oxygen concentration device 28 are sequentially arranged from the upstream until reaching the ozone gas supply path 24. The oxygen gas sensor 27, the ozonizer (ozone gas generator) 7, and the backflow prevention valve 8 are provided in a state where they are connected via a path 25. The PSA oxygen concentrator 28 includes a compressor 4, a dryer 5, and a PSA oxygen concentrator unit 6. The carbon dioxide gas removal device 1 is disposed in front of the PSA type oxygen concentrator 28.

  That is, in this embodiment, immediately after taking in air (atmosphere) 9 as a source gas from the outside, the carbon dioxide gas removal device 1 performs the carbon dioxide gas removal treatment, and then the oxygen gas concentration treatment is performed. In the carbon dioxide removal device 1, a cylindrical container filled with a carbon dioxide adsorption catalyst is provided. When the air passes through the container, the catalyst and air come into contact with each other, and the carbon dioxide gas in the air is adsorbed and separated and removed. The contact time between the air and the catalyst is designed to be 2 seconds in this embodiment, and a contact time at which the catalyst can adsorb almost 100% carbon dioxide is employed. Although a small amount of dust may be generated from the catalyst, the carbon dioxide gas removal device 1 is connected to the filter 2 so that the generated dust does not flow into the ozonizer 7 having a precise discharge electrode and cause a failure. To prevent it.

As the carbon dioxide adsorption catalyst of the carbon dioxide remover 1, a catalyst mainly composed of soda lime is used, but is not particularly limited. However, it is necessary to be a substance that can preferentially remove carbon dioxide in the air by adsorption. In the case of a catalyst mainly composed of soda lime, an appropriate amount of water is required for the carbon dioxide adsorption reaction, but there is an auxiliary mechanism for humidification or water supply to prevent the catalyst from drying and reducing the adsorption performance. Management such as setting up is necessary.
In the present invention, a detailed description up to such a management method is included.

  The carbon dioxide concentration sensor 3 measures the carbon dioxide concentration of the air that has come out of the carbon dioxide removal device 1 and monitors the adsorption performance of the carbon dioxide adsorption catalyst of the carbon dioxide removal device. Thereafter, the air is sent to a PSA type oxygen concentrator (nitrogen separation mechanism) 28, and the oxygen concentration is increased by separating nitrogen. The oxygen concentration of the obtained gas, that is, the concentrated oxygen gas is generally 90% or more, preferably 95% or more, but was 95% at the time of implementation.

  A process in the nitrogen separation mechanism 28 will be described. The air that has passed through the carbon dioxide removing device 1 and the filter 2 is first compressed by the compressor 4 in the nitrogen separation mechanism 28. Next, moisture contained in the air is removed by the dryer 5. Thereafter, nitrogen in the air is adsorbed by the PSA-type oxygen concentrating unit 6 which has zeolite as a main component and adsorbs nitrogen to the same component, and is concentrated into an oxygen-rich gas. The nitrogen gas separated by the PSA type oxygen concentrating unit 6 is released as exhaust gas 26 to the atmosphere outside the apparatus system. The oxygen concentration of the concentrated oxygen gas is measured and monitored by the oxygen gas sensor 27. Thereafter, the concentrated oxygen gas is sent to the ozonizer 7, and oxygen is changed into ozone by discharge. The subsequent mixing process for generating ozone water is as described above.

  As the nitrogen adsorption catalyst of the PSA type oxygen concentrating unit 6, a catalyst mainly composed of zeolite is used, but is not particularly limited. However, it is necessary to be a substance that can preferentially remove nitrogen gas in the air by adsorption.

  In the present embodiment, the carbon dioxide removing device 1 and the PSA oxygen concentrator 28 are directly connected by the path 25, and the carbon dioxide removing step and the nitrogen gas removing step are continuously performed. Is called. With such a configuration, the overall configuration of the apparatus becomes compact, and ozone water can be supplied to the object while generating the ozone water at a site where the ozone water is required.

  In summary, in the first embodiment, a step of removing carbon dioxide gas from the air is performed in a pre-process for generating concentrated oxygen gas.

Note that water (compressor drain) 10 and water (dryer drain) 11 are discharged in the raw material air compression step by the compressor 4 and the raw material air dehumidification drying step by the dryer 5. In this example, the amount of concentrated oxygen gas (= ozone gas amount) supplied to the ozonizer 7 was 28 L / min, and the supply gas pressure to the ozonizer 7 was 0.2 MPa. The ozone generation capacity of the ozonizer 7 was 350 g / h, and the generated ozone gas concentration was 210 g / Nm ³ under the conditions of this example.

(Second Embodiment)
FIG. 2 is a system configuration diagram showing a second embodiment of the ozone water generator of the present invention. Unlike the embodiment of FIG. 1, in this embodiment, the carbon dioxide gas removal device 1 is arranged at the rear stage of the nitrogen separation mechanism 28. That is, in the present embodiment, nitrogen removal processing is performed on the external air in advance, and then the carbon dioxide gas is removed by the carbon dioxide removal device 1 in the path 25 before reaching the ozonizer 7. That is, the carbon dioxide removing device 1 is disposed at the rear stage of the PSA type oxygen concentrating device 28. In other words, in the second embodiment, a step of removing carbon dioxide gas from the concentrated oxygen gas is performed in a step after the generation of the concentrated oxygen gas. Also in this embodiment, the PSA-type oxygen concentrator 28 and the carbon dioxide removal device 1 are directly connected by the path 25, and the nitrogen gas removal step and the carbon dioxide removal step are continuously performed. Is called.

  As a result of the tests carried out to complete the present invention, an apparatus that does not remove carbon dioxide, that is, a conventional ozone water generator in which the carbon dioxide removing apparatus 1 is removed from the apparatus of the present invention was used. According to the comparison between the conventional apparatus and the apparatus of the present invention, the concentration of ozone water was significantly increased only when carbon dioxide was removed as in the present invention. An improvement in sex was observed. Hereinafter, the results of the implementation test will be described.

(Comparison result)
(1) Example Ozone water was generated using the apparatus of the first embodiment shown in FIG. After the oxygen concentration of the concentrated oxygen gas was increased to approximately 95% by the PSA type oxygen concentrator 28, discharge by the ozonizer 7 was performed to generate ozone gas, and gas-liquid mixing was performed to generate ozone water (water temperature was 2 ° C. Use tap water from Sakai City, Niigata Prefecture at 5 ℃ to 5 ℃). As a premise for the generation of ozone gas, a carbon dioxide removal device 1 filled with a carbon dioxide removal catalyst is provided upstream (upstream) of the PSA type oxygen concentrator 28 (immediately after taking in external air in the example of FIG. 1). Yes. The capacity of the carbon dioxide gas removal catalyst was designed to be a capacity capable of obtaining a contact time of 2 seconds or more while the raw material air passed through the catalyst. Consideration was made so that the flow path was kept even so that no untreated gas was present when passing through, so that carbon dioxide gas was reliably removed.

  About the obtained ozone water, the dissolved ozone concentration which reached | attained ozone water and the change of the ozone concentration with time progress are shown in FIG. Approximately 25 minutes after the generation, the ozone concentration reached 87 mg / L, which is the highest concentration, and no decrease in concentration was observed even if the operation was continued thereafter. As a result, the ozone water obtained by the present embodiment is stable with a very small amount of deaerated gas when it is fed from the discharge pump 23 for ozone water feed compared to the conventional method, and the generation of ozone gas. It was confirmed that it has a desirable function of suppressing the ozone concentration as much as possible, that is, having a small decrease in the concentration of ozone water and high concentration maintenance.

(2) Comparative Example As a comparative example, ozone water was generated using an apparatus excluding the carbon dioxide gas removing apparatus 1 from the apparatus of the first embodiment shown in FIG. In the comparative example, the implementation conditions such as temperature are almost the same as those in the example. Also in this example, the oxygen concentration of the concentrated oxygen gas is increased to approximately 95% by the PSA type oxygen concentrator 28, and then discharge is given by the ozonizer 7, generating ozone gas, and mixing the gas and liquid to generate ozone water. did.

  About the obtained ozone water, transition of dissolved ozone concentration of ozone water and change of dissolved ozone concentration with time passage were measured. The measurement results are shown in FIG. After the production, the concentration increased until 18 minutes, but thereafter began to decrease. The dissolved ozone concentration reached only 78 mg / L, and even if the operation was continued thereafter, it continued to decline clearly. By 35 minutes, it decreased to about ½, and continued to decline thereafter. From this result, it was judged that it was impossible to store a large amount in the tank with the target high-concentration ozone water. The ozone water obtained by the present embodiment is completely different from the ozone water generated by the ozone gas from which the carbon dioxide gas has been removed, and loses its effectiveness in a very short time after being fed from the discharge pump 23 for ozone water feeding. confirmed.

  Next, the mechanism that brings about the effect of the present invention will be examined. Although this mechanism is in an estimation stage, it does not affect the effect of the present invention at all whether it is possible to implement by the person skilled in the art of the present invention.

  Since ozone is a hardly soluble gas, it tends to exist as bubbles in water. However, since the bubbles are degassed over time, it is difficult to dissolve them in water for a long time. In order to suppress the decrease in concentration, there are a method of forming fine bubbles by a method of generating cavitation, a method of dispersing ozone molecules in water, and the like.

  Ozone is extremely reactive in an alkaline aqueous solution, and self-decomposition tends to proceed. Therefore, the decomposition speed is higher than the speed of generating and increasing the concentration. As a result, it is difficult to store ozone water and generate and maintain it at a high concentration. When the target water is acidified, ozone self-decomposition is suppressed, and a relatively high ozone concentration can be achieved and maintained.

  Considering this “suppression of ozone self-decomposition”, there are many methods of adding carbon dioxide, but contrary to this idea, oxygen or oxygen-rich gas from which carbon dioxide has been removed is used. A method of generating ozone water has not been proposed yet. In the present invention, although it has never been noticed so far, 1) an ozone consuming substance (ozone scavenger) is generated by dissolving carbon dioxide in water, and 2) the generated ozone consuming substance is extremely We focused on the increase of the underwater space for ozone gas dissolution by removing carbon dioxide which is easily dissolved in water. In particular, suppressing the generation of ozone-consuming substances, that is, preventing the generation of carbon-derived ozone-reactive substances in water contributes to the ability to generate ozone water more than keeping the pH acidic. It seems that.

  As described above, those skilled in the art have focused on the point of “suppression of ozone self-decomposition” and have tended to make trial and error to make the target water acidic. Was positive. In the present invention, the above points 1) and 2), that is, although not directly related to the pH of water, have been sought for the direction of denying the incorporation of carbon dioxide gas, which has been positive in the past. It is worth noting that it was obtained as a fruit that went in a completely different direction from technology. It is also worth noting that the removal of carbon dioxide gas, which is easily dissolved in water, was considered in order to promote ozone gas dissolution.

  The inventors have conceived of an ozone water generation device having a novel configuration by combining a carbon dioxide gas removal device at the front stage or the rear stage of a general PSA type oxygen concentrator with the above-described examination. It was. That is, the ordinary person skilled in the art uses a general PSA type oxygen concentrator alone for that purpose, and has no motivation to combine the carbon dioxide removing device. This is because a general PSA-type oxygen concentrator does not have the premise of combining not only a carbon dioxide removing device but also a device that changes other components. Furthermore, as described above, even if a person skilled in the art pays attention to maintaining the concentration of ozone water, it usually searches for the direction of maintaining acidity, that is, adding carbon dioxide gas. It cannot be easily conceived.

  Since it does not generate carbon dioxide-derived highly ozone-reactive substances, removing carbon dioxide keeps the physical properties of the water suitable for ozone water, and as a result stabilizes ozone water to increase the concentration reached and suppress the concentration drop Thus, a high concentration can be maintained for a long time. Furthermore, a large amount of ozone water can be stored and generated. The reason is estimated as follows. In the above-described embodiment, the raw water is not pure water but general water such as tap water, and the raw material gas is not pure oxygen, but is concentrated and separated from air and concentrated oxygen gas having a concentration of 90% to 95%. There is a requirement to use this as a raw material gas for ozone.

(1) Mechanism 1: Background of generation of ozone scavenger and effects by suppressing generation The phenomenon that occurs when carbon dioxide gas is contained in ozone gas and dissolved in ozone water for a while is as follows. As a premise, the raw water is not so-called ultrapure water but water containing the substance to be reacted, so if normal air is mixed into the raw water as it is, ozone-consuming substances are generated by the mixing of carbonic acid, It is thought to promote the decomposition of ozone. On the contrary, if the carbon dioxide gas is removed, this phenomenon can be suppressed, so that the performance of the ozone water can be improved very clearly.

When carbon dioxide is dissolved in water, the following equilibrium reaction occurs.
CO ₂ (gas) ＣＯ CO ₂ (aqueous solution)

Carbonic acid dissolved in water becomes carbonic acid (aqueous solution) in an acidic atmosphere depending on the hydrogen ion concentration index (pH).
CO ₂ (aqueous solution) + H ₂ O⇔H ₂ CO ₃ (aqueous solution)

Further, carbonic acid (aqueous solution) becomes hydrogen carbonate ions depending on the hydrogen ion concentration index (pH), and further becomes carbonate ions in an alkaline atmosphere.
H ₂ CO ₃ (aqueous solution) ⇔ HCO ₃ ⁻ (aqueous solution) + H ⁺
HCO ₃ ⁻ (aqueous solution) ＣＯ CO ₃ ²⁻ (aqueous solution) + H ⁺

  As can be seen from the above reaction, if a substance that consumes hydrogen ions in the water (alkaliness component; calcium carbonate, etc.) is present in the water, the reaction proceeds to the right side, otherwise the pH becomes acidic. . Therefore, carbonated water generally shows weak acidity. That is, when carbon dioxide gas is dissolved in water, it exists as carbonic acid on the acidic side, hydrogen carbonate ion in the neutral side, and carbonate ion in the alkaline side.

When these ions react with inorganic salts (sodium, potassium, calcium, etc.) in water, ozone consuming substances (ozone scavengers) such as carbonates and bicarbonates are generated, which may reduce the ozone concentration. For example, when the pH is neutral and sodium is contained as an inorganic salt in the raw material water, sodium bicarbonate which is an ozone consuming substance is generated by the following reaction.
HCO ₃ ⁻ + Na ⁺ → NaHCO ₃

  Therefore, concentrating air from which carbonic acid has been removed, or removing carbonic acid from the concentrated oxygen gas to produce ozone gas by discharge and gas-liquid mixing with water to produce ozone water prevents the generation of ozone-consuming substances and dissolves them. It is thought that the decrease in ozone concentration can be suppressed. Similarly, the ozone water concentration can be kept high without causing ozone decomposition and disappearing even if the ozone water generation process of generating and mixing the ozone gas is continuously achieved as stabilized ozone water. It becomes possible.

(2) Mechanism 2: Increase in the space where ozone can be dissolved in water When the composition components of air are individually dissolved in water at 0 ° C. and 1 atm, the components derived from air in water are oxygen 49 mL / L, nitrogen 2.4 mL / L, argon 5.6 mL / L, carbonic acid 170 mL / L, and the amount of carbonic acid increases remarkably. When the oxygen ratio in the concentrated oxygen gas obtained by the PSA type oxygen concentrator is 95% and the ratio of other gases is 5%, the space where ozone can exist in water is occupied by carbonic acid. When ozone water is generated by a conventional method that does not use a carbon dioxide gas removal catalyst, carbon dioxide gas, which has much better solubility in water than other gases, preferentially fills the space in which gas in water can be dissolved. On the other hand, although ozone gas is a material property that is difficult to dissolve although repeated mixing, it is difficult to dissolve in water, and the dissolved ozone concentration cannot be increased predominately. Also, the rate occupied by carbon dioxide gas increases with time. It is considered that the phenomenon that the ozone concentration decreases becomes remarkable.

  The embodiment of the present invention includes a step of removing carbon dioxide in the air as the raw material gas, or further removing carbon dioxide from the concentrated oxygen gas (oxygen concentration 90% to 95%) separated and concentrated from the air. . The oxygen-rich gas obtained here can be dissolved in water by gas-liquid mixing as ozone gas by discharge, and the solubility of ozone can be enhanced with surprising efficiency. If it demonstrates from another angle, the loss | disappearance of ozone can be suppressed and the probability that ozone exists will be raised significantly. According to this embodiment, compared with the case where carbon dioxide gas is not removed, the concentration reached by the dissolved ozone concentration of ozone water is increased by 10% or more, and the concentration maintenance characteristic is increased several tens of times.

  In the above embodiment, as the carbon dioxide adsorption catalyst of the carbon dioxide removal apparatus 1, a catalyst mainly composed of soda lime is used. In the present invention, the requirement required as a carbon dioxide adsorption catalyst is to preferentially remove carbon dioxide in the air by adsorption.

  Moreover, in the said embodiment, as a nitrogen adsorption catalyst of the PSA type oxygen concentrator 28, what has a zeolite as a main component is used. In the present invention, a requirement required as a nitrogen adsorption catalyst of a PSA type oxygen concentrator is to preferentially remove nitrogen gas in the air by adsorption.

  Furthermore, in the present invention, a carbon dioxide gas removing device and a PSA oxygen concentrating device are essential, but these devices are provided as separate devices. Then, each apparatus mainly removes carbon dioxide gas at a different position and at different timing (step for removing carbon dioxide gas preferentially), and mainly removes nitrogen gas (nitrogen gas is given priority). Removing step). The order of these two steps does not matter. However, between these two processes, the gas to be processed is not exposed to substantially other processes, and is connected as shown in the embodiment and continuously processed. For example, there is no process for fundamentally changing the properties of the gas to be processed between the two processes or for fundamentally changing the components of the gas to be processed.

  With such a configuration, the overall configuration of the apparatus becomes compact, and ozone water can be supplied to the object while generating the ozone water at a site that requires ozone water. In addition, an excellent ozone water generator can be easily provided while utilizing the conventional PSA oxygen concentrator to the maximum extent.

  Further, as described above, the present invention suitably does not include water having an electrical resistivity of 18.24 MΩ · cm as a theoretical value at 25 ° C., so-called ultrapure water, as raw material water to be treated. This is because such ultrapure water is scarcely meaningful as a treatment target of the present invention because it contains almost no inorganic salt or the like that is a source of ozone-consuming substances that consume ozone gas. That is, the raw material water referred to in the present invention is exclusively intended for water containing a predetermined amount or more of a substance such as an inorganic salt that generates a predetermined amount or more of ozone consuming material. Here, “a predetermined amount or more of ozone consuming substance” means an amount that is higher than a level that causes a problem that the concentration of the generated ozone water is low and the high concentration maintenance characteristic is impaired.

  Moreover, the gas-liquid mixing apparatus used by the said embodiment employ | adopts the method of mixing ozone gas and water using an ejector. However, any method / apparatus capable of gas-liquid mixing other than an ejector is included in the content of the present invention.

  The ozone water obtained by the present invention has a higher sterilizing effect, cleaning effect, deodorizing effect, and substance peeling effect from the target surface as compared with the conventional one, and the effect is also maintained for a long time. Therefore, the ozone water obtained by the present invention, that is, the ozone water in which the ozone consumption substance (ozone watermelon venger) is not increased, can be applied to a wider technical field and industrial field than the conventional ozone water.

  The present invention is intended to be variously modified and applied by those skilled in the art based on the description in the specification and well-known techniques without departing from the spirit and scope of the present invention. Included in the scope for protection. Moreover, you may combine each component in the said embodiment arbitrarily in the range which does not deviate from the meaning of invention.

  According to the present invention, ozone water having a high dissolved ozone concentration and high concentration maintaining characteristics can be obtained. Therefore, it is difficult to achieve a high concentration which was a weak point of ozone water, and unstable and mass production is difficult. It can be applied to a wide range of technical and industrial fields and can be spread.

1 Carbon Dioxide Removal Device 2 Filter 3 Carbon Dioxide Concentration Sensor 4 Compressor 5 Dryer 6 PSA (Pressure Swing Adsorption) Type Oxygen Concentration Unit 7 Ozonizer (Ozone Gas Generator)
8 Backflow prevention valve 9 Air (atmosphere)
10 Water (Compressor drain)
11 Water (dryer drain)
12 Undissolved surplus ozone gas decomposition device 13 Mixed ozone gas undissolved bubble separation tank 14 Ejector (gas-liquid mixing device)
15 Exhaust gas (oxygen gas after ozone decomposition)
16 Tap water (raw water)
17 Chiller 18 Dissolved ozone concentration meter 19 Water temperature meter 20 Cooling water circulation pump 21 Ozone water generation circulation pump 22 Storage tank 23 Ozone water supply discharge pump 24 Ozone gas supply path 25 Path 26 Exhaust gas (nitrogen gas after separation)
27 Oxygen gas sensor 28 PSA oxygen concentrator (nitrogen separation mechanism)
100 Ozone gas generator (ozone gas supply line)
200 Ozone water generation circulation line

Claims (3)

PSA (P) which generates concentrated oxygen gas by adsorbing and separating nitrogen gas from the air
(resisting Swing Adsorption) type oxygen concentrator,
An ozone gas generator for changing the concentrated oxygen gas into ozone gas by discharge;
A gas-liquid mixing device for generating ozone water by dissolving the ozone gas in raw material water;
An ozone water generator comprising:
It further includes a carbon dioxide gas removal device that is disposed in the front stage or the rear stage of the PSA type oxygen concentrator and includes a carbon dioxide adsorption catalyst mainly composed of soda lime and removes carbon dioxide from the air or the concentrated oxygen gas. Ozone water generator.   2. The ozone water generation apparatus according to claim 1, further comprising a humidification mechanism or a hydration mechanism for supplying moisture to the soda lime of the carbon dioxide removal device and maintaining a carbon dioxide adsorption effect. Carbon dioxide gas is removed from the air with an adsorbent containing soda lime as a main component, then the air from which the carbon dioxide gas has been removed is dehumidified, and then nitrogen gas is adsorbed and separated from the air by an adsorption action to concentrate oxygen gas. nitrogen gas is separated from the air to produce concentrated oxygen gas by PSA-type oxygen concentrator for generating, then discharging the concentrated oxygen gas is changed to ozone by, then allowed to dissolve the ozone gas in the water process Is performed continuously , the ozone water production | generation method characterized by the above-mentioned.

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