JP2001291696A - Apparatus for forming gas-dissolved water - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for forming gas-dissolved water, capable of supplying gas-dissolved water in response to the quantity required by varying the forming quantity of gas-dissolved water in response to the variation of usage quantity of gas-dissolved water in an apparatus for forming gas-dissolved water by means of a direct gas-liquid contacting dissolution method using an ejector. SOLUTION: This apparatus for forming gas-dissolved water comprises a gas dissolution unit, using an ejector 1, a dissolving-water feed pipe 3 that feeds the dissolving water to the ejector, a gas feed pipe 5 that feeds the gas to the ejector, a transfer path 6 that transfers the gas-dissolved water from the gas-dissolution unit to a use point 8, a gas-liquid separator 7 arranged on the transfer path, and a mixing-water conducting pipe 9 that is connected to the transfer path to make the mixing water mix with the gas-dissolved water.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an apparatus for producing gas-dissolved water. More specifically, the present invention relates to an apparatus for producing gas-dissolved water by a direct gas-liquid contact dissolution method capable of varying the production amount of gas-dissolved water in response to a variation in the amount of gas-dissolved water used.

[0002]

2. Description of the Related Art Removal of fine particles, organic substances, metals, and the like from the surface of electronic materials such as silicon substrates for semiconductors, glass substrates for liquid crystals, and quartz substrates for photomasks is necessary to ensure product quality and yield. Very important. For this purpose, wet cleaning is performed at a high temperature using a concentrated chemical based on hydrogen peroxide, which is a so-called RCA cleaning method, and a mixed solution of ammonia and hydrogen peroxide (APM) or hydrochloric acid and hydrogen peroxide is used. Mixed solution (HPM)
And so on. The use of these cleaning methods reduces the cost of chemical solutions, the cost of ultrapure water for rinsing, the cost of waste liquid treatment, and the cost of air conditioning that exhausts chemical vapors and prepares fresh air. In recent years, the wet cleaning process has been reviewed in order to reduce the burden on the environment such as mass disposal of drugs and emission of exhaust gas. The present inventors previously dissolved a specific gas in ultrapure water,
We have developed a functional wash water that is prepared by adding a trace amount of chemicals as needed, uses a very small amount of chemicals, and exhibits excellent cleaning effects. This functional washing water has been highly evaluated for its resource saving and environmental preservation, and has been used in place of high-concentration chemicals. Examples of the gas used for the functional cleaning water include ozone gas, hydrogen gas, oxygen gas, rare gas, and carbon dioxide gas. The functional cleaning water in which these gases are dissolved exhibits a cleaning effect comparable to the conventionally used high-concentration chemical cleaning while maintaining properties close to pure water. In particular, ozone-dissolved water is effective for removing organic contamination and metal contamination attached to the surface of electronic materials, and is also a rare gas-dissolved water such as hydrogen gas-dissolved water, oxygen gas-dissolved water, or argon to which a trace amount of ammonia is added. When used in a washing step using ultrasonic waves, an extremely high effect of removing fine particles is exhibited. In the production of ozone-dissolved water, a method using a dedicated dissolving film module having a built-in gas-permeable film having ozone resistance was generally used. On the other hand, the present inventors have developed and put into practical use a system of a direct gas-liquid contact dissolution method combining an ejector and a gas-liquid separator. According to this method, the dissolved gas concentration rises using a device configuration that is significantly simplified as compared with the membrane module method.
The responsiveness of the fall was extremely good, and the practicality was improved. However, the direct gas-liquid contact dissolution method using an ejector has a problem that it cannot widely cope with a fluctuation in the flow rate of the water to be treated. For example, in the case of the membrane module method,
When the flow rate of the water to be dissolved is reduced while the supply condition of the gas to be dissolved is kept constant, the concentration of the dissolved gas increases, and when the amount of the water to be dissolved increases, the concentration of the dissolved gas decreases. For this reason, the same apparatus can be appropriately used for large flow rate and low concentration to small flow rate and high concentration. On the contrary,
In the case of the direct gas-liquid contact dissolution method using an ejector, a flow rate range desired for the ejector, that is, a flow rate range in which the gas to be dissolved can be sucked is determined. In order to efficiently dissolve the gas in the water to be dissolved, good gas suction is essential, and an ejector having a fixed shape has a specific applied flow rate, and the flow rate cannot be arbitrarily changed. That is, if the flow rate is reduced below a predetermined value, the gas will not be sucked, and it will not be practically possible to use it as a gas-dissolved water producing apparatus.

[0003]

SUMMARY OF THE INVENTION The present invention relates to an apparatus for producing gas-dissolved water by a direct gas-liquid contact dissolution method using an ejector. The purpose of the present invention is to provide an apparatus for producing gas-dissolved water that can supply water following a required amount of water.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, mixing water was supplied to a feed line for sending gas-dissolved water from a gas dissolving section by an ejector to a use point. By providing a conduit and combining the mixing water with the gas-dissolved water, it was found that the supply amount of the gas-dissolved water could be increased or decreased in accordance with the variation in the amount of water used, and based on this finding, the present invention was completed. . That is, the present invention provides (1) a gas dissolving section by an ejector, a dissolving water supply pipe for supplying dissolving water to the ejector, a gas supply pipe for supplying gas to the ejector, and gas dissolving water from the gas dissolving section to the use point. An apparatus for producing gas-dissolved water, comprising: a feed path for sending, a gas-liquid separator provided in the feed path, and a mixing water conduit for connecting the mixing water to the gas-dissolved water in contact with the feed path, (2) The apparatus for producing gas-dissolved water according to (1), wherein the mixing water conduit communicates with the feed path downstream of the gas-liquid separator; and (3) the mixing water conduit is upstream of the gas-liquid separator. 2. The apparatus for producing gas-dissolved water according to claim 1, wherein the apparatus communicates with the feed path on the side. Furthermore, as a preferable aspect of the present invention, (4) the apparatus for producing gas-dissolved water according to (1), wherein the mixing water conduit is a conduit branched from a supply line for supply of dissolved water, and (5) a supply of dissolved water. The apparatus for producing gas-dissolved water according to claim 4, wherein a dissolved water supply pump is installed in the pipe, and a branch point from the dissolved water supply pipe to the mixing water conduit is located upstream of the dissolved water supply pump. Can be mentioned.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION An apparatus for producing gas-dissolved water according to the present invention comprises a gas dissolving section using an ejector, a supply pipe for supplying water for dissolution to the ejector, a gas supply pipe for supplying gas to the ejector, It has a feed path for sending gas-dissolved water from the section to the point of use, a gas-liquid separator provided in the feed path, and a mixing water conduit connected to the feed path to join the mixed water with the gas-dissolved water. FIG. 1 is a process system diagram of one embodiment of the apparatus for producing gas-dissolved water of the present invention. In the apparatus according to the present embodiment, the water to be dissolved is supplied to the gas dissolving section by the ejector 1 through the supply pipe 3 for dissolving water by the supply pump 2 for dissolving water.
Gas is supplied through. In the ejector,
The gas to be dissolved comes into direct contact with the gas, and is sent to the feed path 6 as a gas-liquid mixed fluid of the gas-dissolved water and the undissolved gas. The gas-liquid mixed fluid is separated and removed from the gas in a gas-liquid separator 7 provided in the feed path, and is sent to the use point 8 via the feed path. In this embodiment, a mixing water conduit 9 for mixing the mixing water with the gas-dissolved water is provided, and is connected to the feed path on the downstream side of the gas-liquid separator. FIG. 2 is a process flow chart of another embodiment of the apparatus for producing gas-dissolved water of the present invention. In this embodiment, a mixing water conduit 9 for joining the mixing water with the gas-dissolved water is connected to the feed path 6 on the upstream side of the gas-liquid separator 7.

According to the apparatus of the present invention, gas is dissolved in water to be dissolved by using one ejector to produce gas-dissolved water. By doing so, it is possible to respond by changing the production amount of the gas-dissolved water. Therefore, it is preferable to adopt an ejector in which the amount of water corresponding to the minimum usage amount at the use point is set as an appropriate flow rate, that is, an applied flow rate. By adopting an ejector that uses the amount of water equivalent to the minimum amount of use at the point of use as the applied flow rate, when the amount of gas-dissolved water used at the point of use exceeds the minimum amount, it is easy to increase the amount of water for mixing. The production amount of gas-dissolved water can be increased to meet the demand. If an ejector is used that has an appropriate amount of water larger than the minimum amount of gas-dissolved water used at the point of use, an excessive amount of gas-dissolved water is generated when the amount of gas-dissolved water used at the point of use decreases. According to the apparatus of the present invention, since the gas is dissolved in the water to be dissolved by the ejector and the production amount of the gas-dissolved water is adjusted by the mixing water, the concentration of the dissolved gas dissolved by the ejector is reduced by dilution. However, by supplying an appropriate amount of water to the ejector and supplying a maximum amount of the desired gas at an appropriate gas concentration, it is usually possible to produce gas dissolved water having a sufficiently high concentration. Therefore, when the mixing water is merged from the mixing water conduit connected to the feed passage, the dissolved gas concentration of the gas-dissolved water decreases, but the dissolved-gas concentration that achieves the intended use of the gas-dissolved water can be maintained. For example, in an ejector, a concentration of 40 mg
/ L ozone-dissolved water is produced, the concentration of dissolved ozone is 1 mg / L, even if the ozone-dissolved water is diluted 40 times, which is a concentration that can be sufficiently used as washing water. Fluctuations in the amount of gas-dissolved water used at the point of use are often
The maximum and minimum are within a range of several tens of times, which is a range that can be dealt with by the present invention device. If the difference between the maximum usage amount and the minimum usage amount of gas-dissolved water is even greater, select an ejector so that the intended purpose of gas-dissolved water can be fulfilled even if it is diluted with mixing water at the maximum usage amount. When the amount of water used is minimal, excess gas-dissolved water can be generated.

[0007] When producing ozone-dissolved water using the apparatus for producing gas-dissolved water of the present invention, for example, the minimum usage at the point of use is 2 L / min, and the maximum usage is 20 L / min.
Assuming that the flow rate is L / min, one ejector exhibiting the maximum performance at an applied flow rate of 2 L / min is provided. In this ejector, the flow rate greatly deviates from the applied flow rate, for example,
It is difficult to flow water of 3 L / min or more under common sense pressure conditions. In the apparatus of the present invention, 2 L / min of the water to be dissolved is always supplied to the ejector to produce 2 L / min of the ozone dissolved water, and when the use amount of the ozone dissolved water at the point of use increases, from the mixing water conduit, The water for mixing is combined to increase the production of ozone-dissolved water. The junction of the mixing water may be downstream of the gas-liquid separator, as shown in FIG. 1, or may be upstream of the gas-liquid separator, as shown in FIG. When merging on the downstream side, ozone-dissolved water introduced into the gas-liquid separator is always 2 L
/ Min, stable gas-liquid separation can be performed using a small gas-liquid separator. When merging on the upstream side,
Since the excess ozone gas in the air bubbles that have not been completely dissolved in the water to be dissolved that has passed through the ejector partially dissolves in the mixing water, the overall dissolving efficiency can be improved. The amount of the mixing water to be combined can be adjusted by adjusting the opening of a valve installed in the mixing water conduit. In the apparatus of the present invention, the mixing water conduit can be branched from the same pipe as the water to be dissolved supplied to the ejector, or a mixing water conduit can be separately provided. Mixing water conduit,
When simply connected to the pipe of the water to be dissolved supplied to the ejector, it is difficult to balance with the amount of mixing water because the ejector generally has a high water flow resistance.
For this reason, by performing the pressure increase corresponding to the pressure loss of the ejector on the upstream side of the ejector, the water to be dissolved can be stably supplied to the ejector having a large resistance regardless of the flow rate of the mixing water conduit. At this time, it is preferable to equip a filtration device such as an ultrafiltration membrane or a microfiltration membrane between the pressurizing pump and the ejector in preparation for dust generation from the pump. By using the apparatus for producing gas-dissolved water of the present invention, while maintaining the simple apparatus and the rapid concentration response characteristic of the gas-liquid direct contact dissolution method using an ejector, the required flow rate, which is a drawback of the conventional method, is reduced. It can respond to fluctuations.

[0008]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention. In the embodiment, FIG.
Alternatively, ozone-dissolved water was produced using the apparatus shown in FIG. The applied flow rate of the ejector used in the examples was 2 L
/ Min. The ozone generator used as the gas supplier is a device that generates an ozone-containing gas having an ozone concentration of 200 g / Nm ³ at 1 NL / min by silent discharge. Example 1 2 L / min of ultrapure water was fed to an ejector, 1 NL / min of an ozone-containing gas was sucked in, and sent out as a gas-liquid mixed fluid of ozone-dissolved water and undissolved gas, and the undissolved gas was separated in a gas-liquid separator. . The dissolved ozone concentration of the ozone-dissolved water sampled in the washing machine, which was the use point, was 40 mg / L. Example 2 In the same manner as in Example 1, 2 L / min of ultrapure water was fed into the ejector, and 1 NL / min of an ozone-containing gas was sucked into the ejector.
It was sent out as a gas-liquid mixed fluid of ozone dissolved water and undissolved gas. Undissolved gas was separated in the gas-liquid separator, and 8 L / min of ultrapure water for mixing was joined to the feed path on the downstream side of the gas-liquid separator. The dissolved ozone concentration of the ozone-dissolved water sampled in the washing machine was 8 mg / L. Example 3 As in Example 1, 2 L / min of ultrapure water was fed into the ejector, and 1 NL / min of an ozone-containing gas was sucked into the ejector.
It was sent out as a gas-liquid mixed fluid of ozone dissolved water and undissolved gas. 8L of ultrapure water for mixing in the feed path upstream of the gas-liquid separator
/ Min., And undissolved gas was separated in a gas-liquid separator. The dissolved ozone concentration of the ozone-dissolved water sampled in the washing machine was 10 mg / L. Example 4 The amount of ultrapure water for mixing to be merged downstream of the gas-liquid separator was 1
Ozone-dissolved water was produced in the same manner as in Example 2 except that the amount was 8 L / min. The dissolved ozone concentration of the ozone-dissolved water sampled in the washing machine was 4 mg / L. Example 5 The amount of ultrapure water for mixing to be merged on the upstream side of the gas-liquid separator was 1
Ozone-dissolved water was produced in the same manner as in Example 3 except that the amount was 8 L / min. The dissolved ozone concentration of the ozone dissolved water sampled in the washing machine was 5 mg / L. Comparative Example 1 Ozone-dissolved water was produced in the same manner as in Example 1, except that the amount of ultrapure water supplied to the ejector was increased to increase the production amount of ozone-dissolved water. However, even if the driving horsepower of the pump was increased, ultrapure water of 3 L / min or more could not be sent to the ejector. When the maximum supply of 2.9 L / min of ultrapure water that could be supplied to the ejector was supplied, the dissolved ozone concentration of the ozone-dissolved water sampled in the washing machine was 28 mg / L. Comparative Example 2 The ejector was replaced with an ejector at an applied flow rate of 20 L / min, and 20 L / min of ultrapure water was fed into the ejector to suck 1 NL / min of an ozone-containing gas. A gas-liquid mixed fluid of ozone-dissolved water and undissolved gas was sent out, and the undissolved gas was separated in a gas-liquid separator. The dissolved ozone concentration of the ozone dissolved water sampled in the washing machine was 5 mg / L. Comparative Example 3 Ozone-dissolved water was produced in the same manner as in Comparative Example 2, except that the amount of ultrapure water supplied to the ejector was reduced to reduce the amount of ozone-dissolved water produced. However, when the supply amount of ultrapure water to the ejector became 12 L / min, it became impossible to make the ejector suck the ozone-containing gas. Table 1 shows the results of Examples 1 to 5 and Comparative Examples 1 to 3.

[0009]

[Table 1]

As shown in Table 1, by using the apparatus of the present invention, the production amount of ozone-dissolved water can be varied ten times from 2 L / min to 20 L / min using the same ejector. Comparative Example 1 Using Conventional Device
In Nos. 1 to 3, it is difficult to increase the production amount of ozone-dissolved water to 1.5 times or more, and to reduce it by half.

[0011]

By using the apparatus for producing gas-dissolved water of the present invention, it is possible to use a simple apparatus which is a feature of the gas-liquid direct contact dissolution method using an ejector and to maintain the rapid concentration response while maintaining the shortcomings of the conventional method. It is possible to cope with the fluctuation of the required flow rate.

[Brief description of the drawings]

FIG. 1 is a process flow diagram of one embodiment of the apparatus of the present invention.

FIG. 2 is a process flow chart of another embodiment of the apparatus of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ejector 2 Dissolved water supply pump 3 Water supply pipe 4 Gas supply 5 Gas supply pipe 6 Feeding path 7 Gas-liquid separator 8 Use point 9 Mixing water conduit

Claims (3)

[Claims] 1. A gas dissolving section by an ejector, a dissolving water supply pipe for supplying dissolving water to the ejector, a gas supply pipe for supplying gas to the ejector, and a feeding path for sending gas dissolving water from the gas dissolving section to a use point. An apparatus for producing gas-dissolved water, comprising: a gas-liquid separator provided in the supply path; and a mixing water conduit for connecting the mixture water to the gas-dissolved water in communication with the supply path. 2. The apparatus for producing gas-dissolved water according to claim 1, wherein the mixing water conduit communicates with a feed path downstream of the gas-liquid separator. 3. The apparatus for producing gas-dissolved water according to claim 1, wherein the mixing water conduit communicates with a feed path upstream of the gas-liquid separator.