JP2002018253A - Hydrogen dissolving apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare hydrogen dissolved water having necessary concentration by simple constitution. SOLUTION: This hydrogen dissolving apparatus is constituted of a dissolving tank 1 formed so that ultrapure water is supplied to a gas-liquid contact bed 13 filled with a filling material 13a from a water sprinkling nozzle 12 to be stored in a stagnation part 11, a circulating system 2 for circulating water in the tank 1 and feeding prepared hydrogen-containing water, an ejector 3 provided to this system to mix and supply hydrogen, and a supply system 4 for supplying ultrapure water as raw material water. The constitution of the apparatus is simple and highly concentrated hydrogen-containing water with a concentration of about 1 ppm sufficient for the high-degree surface treatment of a semiconductor related product can be prepared.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydrogen dissolving apparatus for dissolving hydrogen supplied to raw water to be supplied into hydrogen-containing water, and is particularly advantageously used in the field of advanced surface treatment of semiconductor-related products. .

[0002]

2. Description of the Related Art As an apparatus for producing hydrogen-containing water, ultrapure water is supplied to a degassing membrane module, and the inside of the module is dissolved in ultrapure water supplied at a high negative pressure by a vacuum pump. The degree of saturation of the gas is significantly reduced, and the degassed ultrapure water is put into the hydrogen gas dissolving membrane module, and hydrogen gas is supplied into the hydrogen gas dispenser using the hydrogen gas supply device. A method for producing hydrogen-containing ultrapure water to be produced has been proposed (see JP-A-11-77023).
According to this method, the concentration of hydrogen dissolved in ultrapure water can be increased with a small amount of supplied hydrogen gas.

However, such a method requires a vacuum pump, a degassing module, and the like, which complicates the configuration of the apparatus, increases the cost, and complicates the operation.
Further, in order to reduce the amount of supplied hydrogen gas and increase the dissolving efficiency by a vacuum degassing method, it is necessary to use a membrane module for dissolving hydrogen. That is, according to Table 1 showing Examples and Comparative Examples of the publication, when an in-line mixer is used instead of the hydrogen gas dissolving membrane module, as shown in Example 8, the hydrogen gas injection amount is 10% in terms of saturation. Even if it is doubled, the dissolved hydrogen gas concentration of the treated water is 0.8
It can only be increased to mg / l.

At this time, the dissolving efficiency is reduced to 5% by increasing the supply amount of hydrogen gas. However, the hydrogen gas dissolving efficiency is reduced to 1.5% in terms of saturation, and the dissolution efficiency is reduced to 29%. Also in the ninth embodiment, the concentration of dissolved hydrogen gas in the treated water was increased to 0.7 mg / l. Therefore, the above-mentioned concentration of 0.8 mg / l was close to the limit of the concentration that could be increased when using the inline mixer. It is estimated that the dissolved hydrogen concentration does not increase much even if the double hydrogen gas injection amount is further increased. In Comparative Examples 1 and 2, even when the hydrogen gas injection amount was ten times as large as the above, the dissolved hydrogen concentration was 0.5 and 0.1.
It is 6 mg / l, and this concentration is almost the same limit, and it is estimated that the dissolved hydrogen concentration does not increase even if the amount of hydrogen is increased.

As shown in FIG. 4, a method for producing hydrogen-containing cleaning water for electronic materials comprises a vacuum pump 100, a degassing membrane module 101, a hydrogen gas dissolving membrane module 102, and the like, as described above. In the method for producing hydrogen-containing ultrapure water using the prepared apparatus, there is a method in which a chemical solution storage tank 103 and a chemical injection pump 104 are provided, and the pH is adjusted by adding diluted ammonia water to the hydrogen-containing ultrapure water. It has been proposed (see JP-A-11-29794).

In this method, in order to adjust the pH to 8 to 11, the chemical solution storage tank 10 for adjusting diluted ammonia water so that a very small amount of ammonia water can be injected.
3 and a tank 1 of normal concentration of ammonia water.
05 and the supply pump 106 are provided. In addition,
In the publication, the tank 105 and the supply pump 106 are omitted. However, in such a system, when adjusting the diluted ammonia water, there is a problem that ammonia leaks to the surroundings due to the tank internal pressure, which makes the operation difficult.

[0007]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems in the prior art, and is capable of producing a required concentration of hydrogen-dissolved water at a low cost at a low cost with a simple structure and easy operation. It is an object of the present invention to provide a hydrogen dissolving apparatus in which leakage of hydrogen is prevented.

[0008]

In order to solve the above-mentioned problems, the present invention provides a hydrogen dissolving apparatus for dissolving hydrogen supplied to raw water supplied to hydrogen-containing water. A vertically-elongated container formed so that the raw water is put therein and the hydrogen-containing water is taken out therefrom, wherein a gas containing oxygen dissolved in the raw water by bringing the hydrogen into countercurrent contact with the raw water; And a container for dissolving the hydrogen.

In addition to the above, the invention according to claim 2 is characterized in that the container enlarges a contact area between the stored raw water and the hydrogen and a retaining section provided so that the stored raw water is retained. A circulating system provided to circulate the water in the stagnation section, and a hydrogen supply means provided to mix the hydrogen into the circulating system. And the following.

According to a third aspect of the present invention, in addition to the above, the contact area enlarging means is provided with a water dispersion supply section provided so as to disperse and discharge the entered raw material water, A gas-liquid contact layer formed of a large number of fillers so that hydrogen flows in contact with and in contact with the hydrogen.

[0011] The invention according to claim 4 is characterized in that, in addition to the features of the invention according to claims 1 to 3, a branch system provided so that the raw water can be divided before the raw water is put into the container;
A gas dissolving apparatus provided with the permeable material provided in the branch system, wherein the raw material water is flowed to one side of the permeable material, and the ammonia dissolving apparatus is configured to flow ammonia water to the other side, A chemical solution injection unit capable of supplying the ammonia water to the other side.

[0012]

FIG. 1 shows an example of the overall structure of a hydrogen dissolving apparatus to which the present invention is applied. The hydrogen dissolving apparatus is an apparatus for dissolving hydrogen supplied to ultrapure water as supplied raw water into hydrogen-containing water, and includes a dissolving tank 1 as a vertically long container, a circulation system 2, and a hydrogen supply. It is constituted by an ejector 3 as means. Reference numerals 4, 5, and 6 denote an ultrapure water supply system, a float valve for discharging gas, and an air drain valve, respectively.

The dissolving tank 1 is formed so that ultrapure water is introduced from above and hydrogen-containing water is taken out from below, and a stagnation section 11 provided so as to retain ultrapure water. It is composed of a watering nozzle 12 and a gas-liquid contact layer 13 as a contact area enlarging means provided so as to enlarge the contact area between pure water and hydrogen, and these are the body 1
4 inside. The watering nozzle 12 is provided so that the ultrapure water contained therein is completely dispersed and discharged above the gas-liquid contact layer 13 in order to improve gas-liquid contact.

The gas-liquid contact layer 13 is formed of a large number of fillers 13a so that ultrapure water and hydrogen flow while contacting each other. The filler 13a is made of a material such as ceramic or resin, and has an appropriate shape such as a sphere, a particle, and a column. Further, it is desirable that the surface of the material has a uniform surface including an uneven surface rather than a cylindrical one having an internal space such as a Raschig ring. If there is a cavity inside, the flow rate of hydrogen is low, so that hydrogen in the cavity is difficult to come out. This is to prevent this, improve the hydrogen substitution property, and increase the gas-liquid contact efficiency. For the same reason, it is desirable to eliminate the space between the stagnation portion 11 and the gas-liquid contact layer 13 so that the water surface of the stagnation portion 11 is formed in the gas-liquid contact layer 13.

The melting tank 1 as described above is manufactured as an extremely low-cost apparatus having, as a main structure, a stainless steel pipe as a body and a ceramic ball filled therein.

The circulation system 2 is provided so as to circulate the water in the retaining section 11 by a circulation pump 21. The ejector 3 is provided in the circulating system 2, and hydrogen for producing hydrogen water is supplied from the circulating system 2 through the inner pipe 11 a and the discharge port 11 b of the retaining section 11. In this example, the circulation pump 21 is also used for the purpose of extracting hydrogen water in which hydrogen, which is a product of the present apparatus, is dissolved. By doing so, the number of pumps can be minimized and the device configuration can be simplified.

The hydrogen dissolving apparatus as described above is operated as follows and exhibits the intended operation and effect. Ultrapure water is produced by a production apparatus (not shown), supplied from the ultrapure water supply system 4 to the dissolution tank 1, and uniformly discharged over the entire upper surface of the gas-liquid contact layer 13 by the watering nozzle 12. The ultrapure water flows down the surface of the filler 13 a provided in the gas-liquid contact layer 13, reaches the retaining portion 11, and stays there for a certain time.
The ultrapure water in the stagnation section 11 in which hydrogen has been dissolved is taken out from the bottom by a circulation pump 21, a part of which is sent to a required destination as produced hydrogen-containing water, and the remaining water is supplied to the circulation system 2. Is returned to the stagnation section 11 again.

Hydrogen is produced by a hydrogen production device (not shown) and supplied to the ejector 3 of the circulation system 2 so as to be sucked into the circulating system. It is put into the part 11 and is discharged into the retaining part 11 from the discharge port 11b through the inner pipe 11a. The water having dissolved hydrogen and having increased solubility is circulated again, and while repeating such circulation, the water reaches the required solubility and is sent to the hydrogen water use system.

On the other hand, the hydrogen mixed in the circulating water rises as bubbles and passes through the gaps between the many fillers 13 a in the gas-liquid contact layer 13. During this time, as described above, it comes into contact with the ultrapure water flowing down the surface of the filler 13a. At this time, since the surface area of the ultrapure water flowing down by the filler 13a is remarkably enlarged, a gas such as oxygen dissolved in the ultrapure water is easily released,
On the other hand, hydrogen that covers the surface of water and is in contact with water is easily dissolved in ultrapure water. As a result, dissolved gases such as oxygen in the ultrapure water are released, and hydrogen is easily dissolved due to a decrease in the solubility. Then, the ultrapure water in which a large amount of hydrogen is dissolved in this way becomes even higher in concentration by being circulated as described above, and becomes hydrogen-containing water of a desired concentration and is supplied to the place of use. become.

By the way, in order to dissolve hydrogen by such a method, it is necessary to supply a large amount of excess hydrogen, so that excess hydrogen is generated together with the already contained gas such as oxygen. The gas is automatically discharged from the top of the gas-liquid contact layer 13 by the float valve 5.

Since the above-described apparatus is constituted mainly by a single dissolving tank 1 having a packed bed and a circulating system 2 having a circulating pump 21 which can also be used for feeding the hydrogen-containing water, Unlike a conventional apparatus, an expensive degassing module and a melting module are not required, and a vacuum pump is not required. Further, the operation of the vacuum pump and the related pressure adjustment are not required, and the operation of the apparatus of the present invention is easy.

The inventors manufactured a hydrogen dissolving apparatus to which the present invention was applied as Example 1, and actually operated the apparatus to obtain the following results. [Specifications of hydrogen dissolution equipment] Dissolution tank Dimensions and materials: Stainless steel tube with a diameter of 100 mm x 1.6 m Height of gas-liquid contact layer: 1 m Filler: Ceramic ball with a diameter of 10 mm Circulation pump capacity: 20 liters / min Operation result of Example 1] Ultrapure water supply: 10 L / min Hydrogen supply: about 4.5 L / min Amount to supply ultrapure water-about 40 ppm Circulating water flow: 20 L / min Water property measurement result: Raw material Ultrapure water produced Hydrogen-containing water Redox potential (SHE) (V); + 0.16-0.10 Dissolved oxygen concentration (mg / l); 8.09 1.90 Dissolved hydrogen concentration (ppm); 0 1.1 Hydrogen dissolution efficiency: Approximately 2.8% (1.1 ppm / 40 ppm) According to the above operation results, silicon wafers and silicon wafers can be easily manufactured with a simple configuration using the present invention at low cost. Semiconductor-related products such as LCD glass substrates The approximately 0.7ppm hydrogen concentration normally required when using advanced surface treatment field beyond enough, it is possible to produce a higher concentration in the hydrogen-containing water dissolving hydrogen.

FIG. 2 shows another example of the structure of the hydrogen dissolving apparatus to which the present invention is applied. The device of this example is different from that of FIG.
Before the ultrapure water is supplied from the supply system 4 to the dissolving tank 1, the branching system 7 is provided so as to be able to divide the ultrapure water, the gas dissolving module 8 which is a dissolving device provided in this system, the chemical solution injection unit 9, Etc. are additional equipment. The gas dissolving module 8 is provided with a large number of porous hollow fibers 81 made of fluororesin or the like as a permeable material, and ultrapure water is flowed into the hollow on one side, and the outer body 8 on the other side.
It is configured such that ammonia water is flown to the two sides.
This apparatus is small and inexpensive because it only dissolves a trace amount of ammonia in ultrapure water. The chemical liquid injection unit 9 is a device capable of supplying ammonia water to the body side, and includes a storage tank 91, a chemical injection pump 92, a chemical liquid supply system 93, a return system 94, and the like.

This additional device is for maintaining the pH of the hydrogen-containing water to be produced within a certain range, and can be operated in that state for a considerable period of time once the operating conditions are adjusted. Therefore, it is possible to provide a device in which a person performs a driving operation. However, it is necessary to adjust the operation conditions at an appropriate time because the properties of the ultrapure water to be supplied and the amount of hydrogen supply change, and the ammonia concentration in the storage tank 91 decreases with the elapse of the operation time. . For this reason, in the apparatus of this example, the PH is automatically controlled. That is, the PH meter 10 is provided in the hydrogen-containing water supply line and the flow control valve 71 is provided in the branch system 7 to control the amount of water flowing through the branch system 7 so that the PH of the hydrogen-containing water falls within a certain range. Like that. Reference numeral 72 is a flow meter.

This device operates as follows. The storage tank 91 stores ammonia water. The aqueous ammonia may have a normal concentration of, for example, about 28 ppm.
When such ammonia water is supplied to the gas dissolving module 8, the ammonia dissolved as ammonia water on the outer surface of the hollow fiber in the ultrapure water in the separated hollow fiber 81 permeates into the ultrapure water, Ultrapure water becomes ammonia-dissolved water at an appropriate concentration. In the apparatus of the present embodiment, the amount of such diverted ammonia-dissolved water is adjusted by the flow rate control valve 71 by the PH meter 10, and this water is supplied to the ultrapure water supply system 4 to generate the hydrogen-containing water. PH for example 9-10
Can be adjusted. The operation result of Example 2 in this case is as follows. The parts that are not particularly described are the same as those in the embodiment of the apparatus shown in FIG. [Operation result of Example 2] Ultrapure water supply amount: 10 L / min Separated water flow amount: 0.05 L / min Water property measurement result: Generated hydrogen-containing water PH; 9.4 Redox potential (SHE) ( V); -0.45 dissolved oxygen concentration (mg / l); 1.7 dissolved hydrogen concentration (ppm); 1.2 hydrogen dissolving efficiency: about 3% (1.2 ppm / 40 ppm) By precisely adjusting the pH with the device of Example 1, the oxidation-reduction potential could be further reduced as compared with the device of Example 1. The hydrogen concentration could be increased.

According to such a pH adjusting device, the conventionally provided device for further diluting the ammonia water and the operation for the device are not required. As a result, ammonia does not leak to the surroundings, and the working environment can be favorably maintained. In this case, if the configuration is such that the PH of the generated water is automatically controlled as in the apparatus of the present embodiment, it is possible to eliminate the need for a normal operation other than when starting and stopping. Further, since the number of tanks and pumps for ammonia is reduced by half as compared with the conventional apparatus, the provision of the branch system 7 does not particularly complicate the apparatus. In addition, since the storage tank 91 stores the ammonia water which is not diluted as described above, when injecting a small amount of ammonia into the hydrogen-containing water, the amount of consumed ammonia becomes extremely small. Appropriate ammonia concentration can be maintained over a long period of time.

FIG. 3 shows still another example of the hydrogen dissolving apparatus to which the present invention is applied. The device of this example is different from the device of FIG.
The contact area enlarging means of the dissolving tank 1 is configured as a bubble column section 14. Therefore, the bubble column section 14 also serves as the retaining section 11 of the apparatus of FIG. The ultrapure water, which is the raw water, is introduced from either above or below, but in the apparatus of this example, it is introduced from below. An outlet chamber 15 of the generated hydrogen-containing water is provided in the upper part, and the circulation system 2 circulates the water in the upper outlet chamber 15 downward through a circulation pump 21 similar to that in FIG. Hydrogen is supplied and hydrogen-containing water is sent to the user. Also in the apparatus of this example, the same hydrogen dissolving performance as the apparatus of FIG. 1 can be obtained by the combination of the bubble column section and the circulation system.

[0028]

As described above, according to the present invention, according to the first aspect of the present invention, there is provided a vertically long container formed so as to contain raw water and take out hydrogen-containing water. Since the gas containing oxygen dissolved in the raw water is degassed and hydrogen is dissolved by bringing it into countercurrent contact with the raw water, the contact between the raw water and hydrogen is improved, and various semiconductor-related products are improved. It becomes possible to produce high-concentration hydrogen-containing water for advanced surface treatment.

According to the second aspect of the present invention, in addition to the above, the hydrogen dissolving apparatus is configured to include a vessel having predetermined components, a circulation system, and hydrogen supply means. And hydrogen are introduced and flowed in a counterflow or a parallel flow, and even when the flow rates are small, the two can be uniformly contacted for a certain long time. In this container,
Since the contact area expanding means is provided so as to expand the contact area between the raw water and the hydrogen by the packed tower system or the bubble column system, the solubility of hydrogen in the raw water can be improved.

[0030] In addition, a stagnant portion is provided in the container so that the raw material water stagnates, and the water in the stagnant portion is circulated by the circulating system, and the hydrogen is supplied to the circulating system by the hydrogen supply means so that hydrogen is mixed therein. In addition, hydrogen can be further mixed into the raw material water in the retaining section in which hydrogen has already been sufficiently dissolved to increase the hydrogen solubility, and the mixed state of the raw water and hydrogen can be made uniform and returned to the retaining section. As a result, the hydrogen concentration in the hydrogen-containing water produced by removing the water in the stagnation section is further increased, and the hydrogen in a homogeneous mixed state is raised vertically in the vessel, thereby improving the contact between the raw water and the hydrogen. Can be better.

Since such a hydrogen dissolving apparatus only has a container, a circulation system, and a hydrogen supply means as described above, the apparatus becomes simple and inexpensive, and the operation is easy. By supplying a certain amount of hydrogen, high-concentration hydrogen-containing water sufficient for advanced surface treatment of various semiconductor-related products can be produced.

According to the third aspect of the present invention, the contact area enlarging means is provided in such a manner that the raw water and the hydrogen are opposed to each other while the raw water and the hydrogen are in contact with each other. And a gas-liquid contact layer formed of a large number of fillers so as to flow, so that the raw water is dispersed and uniformly discharged to the upper portion of the gas-liquid contact layer, and the surface of the large number of fillers is dispersed. Can be brought into opposed contact with hydrogen. As a result, the raw water and the hydrogen are brought into uniform contact on the contact area that is sufficiently large as a whole, and the hydrogen can be easily dissolved in the raw water, so that the hydrogen concentration can be sufficiently increased.

According to the fourth aspect of the present invention, since a branching system having predetermined constitutional requirements, a gas dissolving device, and a chemical liquid injection unit are provided, a chemical solution having a normal concentration which is not diluted is supplied to the raw water flowing through the branching system by the gas dissolving device. Can be dissolved. As a result, by adjusting the flow rate of the raw material water in the branch system, it is possible to accurately supply a trace amount of ammonia to the raw water supplied to the container, and accurately adjust the PH of the raw water to a target value. it can.

In this case, since the branching system is provided at a position before the raw water is supplied to the container, ammonia water can be uniformly dispersed in the container to stabilize the PH value of the hydrogen-containing water and increase the PH value. Can increase the solubility of hydrogen in the raw water in the container.

Further, according to such an apparatus, since it is not necessary to dilute ammonia, it is possible to prevent the leakage of ammonia and to prevent the surrounding working environment from deteriorating.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an example of the overall configuration of a hydrogen dissolution apparatus to which the present invention has been applied.

FIG. 2 is an explanatory diagram of another example of the overall configuration of the hydrogen dissolving apparatus to which the present invention is applied.

FIG. 3 is an explanatory view of still another example of the overall configuration of the hydrogen dissolving apparatus to which the present invention is applied.

FIG. 4 is an explanatory diagram showing an example of the overall configuration of a conventional hydrogen dissolving apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Dissolution tank (vessel) 2 Circulation system 3 Ejector (hydrogen supply means) 7 Branch system 8 Gas dissolution module (gas dissolution apparatus) 9 Chemical liquid injection unit 11 Retention part 12 Watering nozzle (water dispersion supply part, contact area expansion means) 13 Gas-liquid contact layer (contact area enlarging means) 13a Filler (contact area enlarging means) 81 Hollow fiber (permeable material)

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4D011 AA15 4D020 AA01 BA23 BC01 CB01 CB08 CB25 4G035 AA02 AB15 AB28 AC30 AC37

Claims (4)

[Claims] 1. A hydrogen dissolving apparatus for dissolving hydrogen supplied to raw water to be supplied into hydrogen-containing water, comprising: a vertically elongated shape formed so that the raw water is charged and the hydrogen-containing water is taken out. A hydrogen dissolving apparatus, comprising: a container for degassing a gas containing oxygen dissolved in the raw material water by bringing the hydrogen into countercurrent contact with the raw water and dissolving the hydrogen. 2. A contact area enlarging means provided to enlarge a contact area between the stored water and the stored raw water and the hydrogen, wherein the container is provided so as to store the raw water therein. And a circulating system provided to circulate the water in the stagnation section, and a hydrogen supply means provided to mix the hydrogen into the circulating system. Item 6. A hydrogen dissolving apparatus according to item 1. 3. The contact area enlarging means, wherein the raw water and the hydrogen flow in opposition to each other while being in contact with a water dispersion supply unit provided to disperse and discharge the raw water contained therein. The hydrogen dissolving apparatus according to claim 2, further comprising a gas-liquid contact layer formed of a large number of fillers. 4. A gas dissolving apparatus comprising: a branch system provided so that the raw water can be divided before the raw water is put into the container; and a gas dissolving device provided in the branch system and having a permeable material. A gas dissolving device configured such that the raw material water flows on one side of the permeable material and ammonia water flows on the other side, and a chemical solution injection unit capable of supplying the ammonia water on the other side. The hydrogen dissolving apparatus according to any one of claims 1 to 3, wherein: