JP5552792B2 - Gas dissolved water production apparatus and production method - Google Patents

Description

  The present invention relates to a gas-dissolved water manufacturing apparatus and method, and more particularly, to a gas-dissolved water manufacturing apparatus for manufacturing gas-dissolved water by dissolving a gas manufactured by water electrolysis in water. The present invention relates to a method for producing dissolved gas water.

  Conventionally, cleaning of a silicon substrate for a semiconductor, a glass substrate for a liquid crystal, etc., mainly includes a mixed solution of hydrogen peroxide solution and sulfuric acid, a mixed solution of hydrogen peroxide solution, hydrochloric acid and water, hydrogen peroxide solution and ammonia water. This is carried out by a so-called RCA cleaning method in which a concentrated chemical solution based on hydrogen peroxide such as a mixed solution with water is used for cleaning at a high temperature and then rinsed with ultrapure water. However, this RCA cleaning method uses a large amount of hydrogen peroxide, high-concentration acid, alkali, etc., so the chemical cost is high, and the cost of rinsing ultrapure water, the cost of waste liquid treatment, and chemical vapor are exhausted. However, a large cost such as an air conditioning cost for newly preparing clean air is required.

  On the other hand, various efforts have been made to reduce costs in the cleaning process and reduce the burden on the environment. A typical example is a technique for cleaning an object to be processed by ultrasonic cleaning or the like using gas-dissolved water in which a specific gas such as hydrogen gas is dissolved.

  However, as the miniaturization, higher functionality, and higher performance of products in the semiconductor and liquid crystal display manufacturing field proceed, extremely high level of control is required for utilities related to manufacturing. That is, a constant specification with little fluctuation is required.

  For example, gas dissolved water in which gases such as oxygen, hydrogen, ozone, nitrogen, carbonic acid, etc. are dissolved in pure water or ultrapure water, etc., will have various effects on the products produced depending on the dissolved gas concentration. There is an increasing demand to strictly control the amount dissolved in gas to a constant concentration. Under such circumstances, in order to control the flow rate of water and the flow rate of gas more precisely, a mass flow controller (MFC) or the like has been used for gas flow rate control.

  Also, in order to supply cleaner gas, an electrolysis type gas generator that generates oxygen, hydrogen, ozone, or other gas by electrolyzing pure water or ultrapure water is adopted as the gas generator. Things are increasing. In the case of using a gas generator by electrolysis of water, the generated gas contains a large amount of moisture, and various proposals have been made to use in combination with a mechanism for dehumidifying, for example, a dehumidifying film.

  For example, in Patent Document 1, a branched gas supply line is provided in a gas pipe for supplying a dry gas, a gas dissolving device is connected to the gas supply line, and dehydration is performed between the gas pipe and the gas dissolving device. A gas-dissolved water production apparatus is disclosed in which a water removal device such as an agent or a water removal filter is provided and a valve for opening and closing a gas flow path in a gas supply line is provided.

  The gas-dissolved water production apparatus described in Patent Document 1 can remove moisture contained in a gas generated by water electrolysis with a dehydrating agent, a moisture removal filter, or the like and supply it as a dry gas. . However, when the gas-dissolved water production device is stopped for a long time due to maintenance or factory shutdown, the gas generator by water electrolysis is also stopped, so that condensed water accumulates in the piping between the electrode and the dehumidifying membrane. It was found that the condensed water is not sufficiently dehumidified by the dehumidifying membrane when starting the gas-dissolved water production apparatus after long-term shutdown, and may flow into the MFC from the gas supply pipe.

  Patent Document 2 has a gas dissolving device for dissolving a gas generated by electrolysis of water in pure water for the purpose of removing condensed water generated in the gas supply passage of the gas dissolving device. There is disclosed a gas-dissolved water producing apparatus configured to discharge condensed water generated in a gas supply passage of the gas-dissolving apparatus into an apparatus provided with a gas-liquid separator.

JP 2000-70661 A JP 2000-297392 A

  However, since the gas-dissolved water producing apparatus described in Patent Document 2 is for removing condensed water generated in a gas supply passage in the gas-dissolving apparatus, that is, in the gas phase chamber, an electrolysis apparatus that performs electrolysis of water. It is not intended to remove the condensed water generated in the gas supply pipe between the pipe and the MFC.

  As a countermeasure, there can be considered a method in which the dry gas continues to flow through the dehumidifying membrane even when the gas-dissolved water production apparatus is stopped. New problems such as breakage have occurred, and no fundamental solution has been reached. As described above, conventionally, the gas dissolved water supplied to the gas dissolving apparatus through the gas supply pipe provided with the gas dehumidifying apparatus and the gas flow rate control apparatus such as the MFC is supplied to the gas generated by the electrolysis of water in the electrolysis apparatus. None of the manufacturing apparatuses can remove the condensed water generated in the gas supply pipe when the operation is stopped to prevent the inflow to the gas flow rate control apparatus.

  The present invention has been made in view of the above problems, and provides a gas-dissolved water production apparatus that can remove condensate generated in a gas supply pipe when operation is stopped to prevent inflow to a gas flow rate control apparatus. For the purpose. In addition, the present invention provides a method for producing dissolved gas using a dissolved gas production apparatus that can remove condensed water generated in the gas supply pipe when operation is stopped to prevent inflow to the gas flow rate control device. For the purpose.

In order to solve the above problems, first, the present invention provides an electrolysis apparatus for electrolyzing water, a gas dissolution apparatus for dissolving a gas generated by electrolysis of water in pure water, and the electrolysis apparatus. A gas supply pipe that connects the gas phase side of the gas dissolving apparatus; and a pure water supply pipe that communicates with a liquid phase side of the gas dissolving apparatus. The gas supply pipe includes a gas dehumidifier and an inside of the gas dissolving apparatus. A gas-dissolved water production apparatus in which a gas flow rate control device for controlling the gas supply amount to the gas is sequentially attached, and a water droplet removal device is provided in a gas supply pipe between the electrolysis device and the gas flow rate control device A gas-dissolved water production apparatus characterized by the above is provided ( Invention 1).

According to the above invention ( Invention 1), water is electrolyzed by the electrolyzer, and the gas generated by this electrolysis is supplied to the gas dissolving device by accurately controlling the flow rate by the gas flow rate control device to be pure water. By dissolving, gas-dissolved water can be produced. At this time, although the gas generated by the electrolysis of water contains a large amount of moisture, the moisture in the electrolytic gas is removed by the gas dehumidifier so that the moisture does not adversely affect the gas flow rate control device. Yes. Furthermore, when this gas-dissolved water production device is stopped for a long period of time due to maintenance or factory stop, the electrolysis device is also stopped, so condensed water is stored in the piping between the electrode of the electrolysis device and the gas dehumidifier, etc. When the apparatus is started up again, the condensed water moves from the gas supply pipe toward the gas flow rate control apparatus. This condensed water is not sufficiently removed by the gas dehumidifier, but since the water droplet removing device is provided upstream of the gas flow control unit, the condensed water does not reach the gas flow control device, and after a long-term stop, etc. However, it is possible to operate the gas dissolved water production apparatus appropriately.

In the said invention ( invention 1), it is preferable to provide the said water droplet removal apparatus in the gas supply piping between the said gas dehumidification apparatus and the said gas flow control apparatus ( invention 2).

According to the above invention ( Invention 2), since the water droplet removing device is provided in the gas supply pipe between the gas dehumidifying device and the gas flow rate control device on the upstream side of the gas flow rate control unit, it is not removed by the gas dehumidifying device. By reliably removing the condensed water, the condensed water does not reach the gas flow rate control device, and the gas-dissolved water production device can be appropriately operated even after a long-term stoppage.

In the said invention ( invention 1 and 2), it is preferable that the said water droplet removal apparatus is a gas filter ( invention 3). According to this invention ( invention 3), since the gas filter can pass only gas and remove moisture, the condensed water in the gas supply pipe can be surely removed.

In the said invention ( invention 1-3), the gas produced by the electrolysis of the water in the said electrolysis apparatus is hydrogen, oxygen, or ozone ( invention 4).

In the said invention ( invention 1-4), it is preferable that the said gas flow rate control apparatus is a mass flow controller ( invention 5).

According to the above invention ( Invention 5), the mass flow controller is excellent in accurate control of the gas flow rate, but is liable to cause trouble due to moisture mixing, but can be prevented from entering the mass flow controller. ing.

In the said invention ( invention 1-5), it is preferable that the said gas supply piping is SUS, nylon, or a fluorine resin ( invention 6). Further, it is preferable that the gas dissolving device is a gas permeable membrane module for gas dissolution, which is partitioned into a liquid phase chamber and a gas phase chamber by a gas permeable membrane ( Invention 7).

Secondly, the present invention provides a method for producing gas-dissolved water, characterized in that gas-dissolved water is produced using the gas-dissolved water producing apparatus according to any one of claims 1 to 7 ( invention). 8).

According to this invention ( invention 8), water is electrolyzed by the electrolyzer, and the gas generated by this electrolysis is supplied to the gas dissolver by accurately controlling the flow rate by the gas flow rate control device to be pure water. Gas-dissolved water is produced by dissolving. At this time, although the gas generated by the electrolysis of water contains a large amount of moisture, the moisture in the electrolytic gas is removed by the gas dehumidifier so that the moisture does not adversely affect the gas flow rate control device. Yes. Furthermore, when this gas-dissolved water production apparatus is stopped for a long period of time due to maintenance or factory stop, the electrolyzer is also stopped, so that condensed water is stored in the piping between the electrode of the electrolyzer and the gas dehumidifier, When the production apparatus is started up again, the condensed water moves from the gas supply pipe toward the gas flow rate control apparatus. This condensed water is not sufficiently removed by the gas dehumidifier, but since the water droplet removing device is provided upstream of the gas flow control unit, the condensed water does not reach the gas flow control device, and after a long-term stop, etc. However, the gas-dissolved water production apparatus can be properly operated.

  According to the gas-dissolved water production apparatus of the present invention, water is electrolyzed by an electrolyzer, and the gas generated by the electrolysis is supplied to the gas dissolver by accurately controlling the flow rate by a gas flow rate controller. Gas-dissolved water can be produced by dissolving in water, and when this gas-dissolved water production device is stopped for a long time due to maintenance or factory stop, the electrolysis device is also stopped, so the piping between the electrode and the dehumidifying membrane When the condensed water is stored in the gas dissolved water production apparatus and the gas dissolved water production apparatus is started up again, the condensed water moves from the gas supply pipe toward the gas flow rate control apparatus. Since this condensed water is not sufficiently removed by the gas dehumidifier, there is a possibility that it will interfere with the gas flow control device if it enters the gas flow control device, but a water droplet removal device is provided upstream of the gas flow control unit. Therefore, the condensed water does not reach the gas flow rate control device, and the gas-dissolved water production device can be properly operated even after a long-term stop.

It is a system diagram explaining the gas dissolved water manufacturing apparatus and manufacturing method concerning one embodiment of the present invention.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a system diagram illustrating a gas-dissolved water production apparatus according to an embodiment of the present invention.

  In FIG. 1, 1 is a gas production part, 2 is a gas dissolution membrane module which is a gas dissolution apparatus. The gas production unit 1 includes an electrolysis device 3 and a gas-liquid separator 4, and the electrolysis device 3 includes a cathode chamber 6 and an anode chamber 7 partitioned via an ion exchange membrane 5. A gas supply pipe 8 is provided so as to connect the gas dissolving membrane module 2. The gas supply pipe 8 is sequentially provided with a dehumidifying film 9 serving as a gas dehumidifying device and a mass flow controller (MFC) 10 serving as a gas flow control device following the gas production unit 1. A gas filter 11 serving as a water droplet removing device is provided in front of (upstream side) of the MFC 10. On the other hand, 12 is a pure water supply pipe. This pure water supply pipe 12 communicates with the gas dissolving apparatus 2 and is connected to the electrolysis apparatus 3 by a branch pipe 12a provided in the middle.

  In the apparatus configuration as described above, the gas-dissolving membrane module 2 is divided into a liquid phase chamber 2b on the liquid phase side and a gas phase chamber 2c on the gas phase side by the gas permeable membrane 2a. A condensed water extraction pipe 2d is attached to the gas phase chamber 2c, and this condensed water extraction pipe 2d communicates with a condensed water removal mechanism (not shown). A hydrogen-dissolved water supply pipe 13 is connected to the liquid phase chamber 2b.

  The gas permeable membrane 2a is not particularly limited as long as it does not permeate water and permeates gas dissolved in water. For example, polypropylene, polydimethylsiloxane, polycarbonate-polydimethylsiloxane block copolymer Examples include polymers, polymer films such as polyvinylphenol-polydimethylsiloxane-polysulfone block copolymers, poly (4-methylpentene-1), poly (2,6-dimethylphenylene oxide), polytetrafluoroethylene, and the like. it can.

  Although there is no restriction | limiting in particular as gas supply piping 8, If gas barrier property etc. are considered, fluorine resin, such as SUS, nylon or polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), etc. Tube material can be used.

  The effect | action is demonstrated about the said structure. First, ultrapure water is supplied from the pure water supply pipe 12. The raw water supplied to the pure water supply pipe 12 may be pure water that has cleanliness that satisfies the application used at the point of use and does not contain a substance that extremely deteriorates or alters the gas permeable membrane 2a. For example, deaerated water or the like can be used as pure water depending on the application.

  The ultrapure water flows from the pure water supply pipe 12 through the branch pipe 12a into the electrolysis apparatus 3, where water is electrolyzed, and hydrogen gas is introduced to the cathode chamber 6 side by electrolysis of water. Arise. On the other hand, oxygen gas is generated on the anode side, and this oxygen gas is discharged out of the system from the anode chamber 7 through an oxygen gas outflow pipe (not shown). The surplus water remaining in the electrolyzer 3 is also discharged through this outflow pipe.

  As a result, a gas-liquid mixture of hydrogen gas and water flows out from the cathode chamber 6, and this gas-liquid mixture flows into the gas-liquid separator 4 through the gas supply pipe 8. Hydrogen gas and water are separated in the gas-liquid separator 4, and the hydrogen gas is guided toward the gas dissolution membrane module 2 through the gas supply pipe 8. On the other hand, water stays in the gas-liquid separator 4.

  Here, the hydrogen gas supplied from the electrolyzer 3 includes saturated water vapor, but when the hydrogen gas passes through the dehumidifying film 9, the water vapor is removed, and the dry hydrogen gas is supplied to the MFC 10. The flow rate is precisely controlled by the MFC 10 and flows into the gas phase chamber 2c of the gas dissolving membrane module 2. On the other hand, ultrapure water is supplied to the liquid phase chamber 2 b of the gas dissolution membrane module 2 through the pure water supply pipe 12. The hydrogen gas in the gas phase chamber 2c passes through the gas permeable membrane 2a and enters the liquid phase chamber 2b, where it is dissolved in ultrapure water to obtain hydrogen-dissolved water. At this time, since the amount of supplied hydrogen gas is precisely controlled by the MFC 10, hydrogen-dissolved water having a predetermined concentration of dissolved hydrogen gas can be produced.

  Further, ultrapure water is always supplied from the pure water supply pipe 12 into the liquid phase chamber 2b of the gas dissolution membrane module 2, and saturated water vapor exists in the liquid phase chamber 2b, and this water vapor is gas. Passing through the permeable membrane 2a, the gas diffuses back into the gas phase chamber 2c. Then, the water vapor that has entered the gas phase chamber 2c due to the reverse diffusion is condensed in the gas phase chamber 2c to generate condensed water.

  As described above, condensed water is generated in the gas phase chamber 2c, and this condensed water is immediately discharged from the condensed water discharge pipe 2d connected to the lower side of the gas phase chamber 2c by a condensed water removing mechanism (not shown). . Therefore, condensed water does not stay in the gas phase chamber 2c.

  The hydrogen-dissolved water produced by the gas-dissolved membrane module 2 in this manner flows out of the system through the hydrogen-dissolved water supply pipe 13 and is sent to a cleaning process in a semiconductor manufacturing factory, for example, for a semiconductor substrate such as a silicon wafer. Used as washing water.

  Next, the operation | movement at the time of restart after the long-term operation stop of the gas dissolved water manufacturing apparatus which concerns on this embodiment is demonstrated. When the gas dissolved water production apparatus is stopped for a long period of time, the electrolysis apparatus 3 is also stopped, so that condensed water is stored in the gas supply pipe 8 between the electrolysis apparatus 3 and the dehumidifying membrane 9. When the gas-dissolved water production apparatus is started up again, hydrogen gas is supplied again from the gas supply pipe 8 to the gas phase chamber 2c of the gas-dissolved membrane module 2, and condensate water stored in the gas supply pipe 8 accordingly. Also moves in the gas supply pipe 8 toward the gas dissolution membrane module 2. Since this condensed water is not water vapor, it is not so much removed by the dehumidifying film 9. Therefore, until this state, the condensed water reaches the MFC 10 and has an adverse effect. However, in the present embodiment, the gas filter 11 is provided in front of (upstream side) of the MFC 10, and the condensed water is removed by the gas filter 11 and does not reach the MFC 10. It is possible to operate the dissolved water production apparatus appropriately.

  Although the present invention has been described based on one embodiment, the present invention is not limited to the embodiment.

  For example, in the present embodiment, the gas filter 11 as a water droplet removing device is provided in the gas supply pipe 8 between the MFC 10 and the dehumidifying membrane 9, but in the gas production unit 1, the downstream side of the gas-liquid separator 4 ( It may be provided at a location 11a shown in the figure, or may be provided between the gas production unit 1 and the dehumidifying film 9 (location 11b shown).

  Further, the water droplet removal device is not limited to the gas filter 11 and may be a water droplet trap tube, silica gel, or the like. Moreover, as a gas dehumidification apparatus, not only the dehumidification film | membrane 9 but a silica gel can be used.

  The gas to be supplied is not limited to hydrogen as long as it can be supplied by electrolysis of water, and can be applied to oxygen or ozone gas. As the gas flow rate control device, MFC 10 is preferable. In this case, the type of MFC may be selected according to the gas to be supplied such as hydrogen, oxygen or ozone.

  Furthermore, as the gas dissolving device, the gas dissolving membrane module 2 using the gas dissolving membrane is preferable, but not limited thereto.

  Furthermore, the branch pipe 12a for supplying raw water to the electrolyzer 3 may be provided independently from the pure water supply pipe 12 for supplying ultrapure water to the liquid phase chamber 2b of the gas dissolution membrane module 2. Further, the ultrapure water supplied to the liquid phase chamber 2b may be supplied with ultrapure water whose pH has been adjusted in advance by adding acid or alkali as necessary.

  Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[Example 1, Comparative Example 1]
Hydrogen dissolved water was manufactured using the gas dissolved water manufacturing apparatus shown in FIG. Details of the apparatus and measurement conditions are as follows.

Gas permeable membrane 2a of gas dissolution membrane module 2: "Lixel G284" manufactured by Celgard Co., Ltd.
Raw water: Degassed ultrapure water Raw water flow rate: 20 L / min
Raw water temperature: 25 ℃
Hydrogen gas supply rate: 270cc / min
Dissolved hydrogen gas concentration: 1.2 ppm (mg / L)

  After continuously operating for 3 hours under the above conditions, the apparatus was stopped for 6 hours, 1 day, 3 days, and 7 days, respectively. Subsequently, the presence or absence of a failure of the MFC 10 when the gas dissolved water production apparatus was restarted was confirmed (Example 1). The results are shown in Table 1. Moreover, in the gas dissolved water manufacturing apparatus shown in FIG. 1, after operating continuously for 3 hours using the same apparatus except not installing the gas filter 11, the apparatus is operated for 6 hours, 1 day, 3 days, and 7 days, respectively. Stopped. Subsequently, the presence or absence of a failure of the MFC 10 when the gas-dissolved water production apparatus was restarted was confirmed (Comparative Example 1). The results are shown in Table 1.

[Examples 2 and 3]
In the gas-dissolved water production apparatus shown in FIG. 1, the gas filter was continuously operated for 3 hours in the same manner using the gas filter installed at the position 11a (Example 2) and the gas filter installed at the position 11b (Example 3). Thereafter, the apparatus was stopped for 6 hours, 1 day, 3 days and 7 days, respectively. Subsequently, it was confirmed whether or not there was a failure in the MFC 10 when the gas dissolved water production apparatus was restarted. The results are shown in Table 1.

  As is clear from Table 1, in Comparative Example 1 having no gas filter 11, troubles caused by condensed water occurred in MFC when the apparatus was restarted after stopping the apparatus for one day or more. No trouble occurred even after 7 days of outage.

DESCRIPTION OF SYMBOLS 1 ... Gas production part 2 ... Gas melt | dissolution membrane module (gas melter)
3 ... Electrolysis device 8 ... Gas supply pipe 9 ... Dehumidifying membrane (gas dehumidifying device)
10. Mass flow controller (MFC) (gas flow rate control device)
11 ... Gas filter (droplet removal device)
12 ... Pure water supply piping

Claims (7)

An electrolysis apparatus that performs electrolysis of water, a gas dissolution apparatus that dissolves gas generated by water electrolysis in pure water, and a gas supply pipe that connects the electrolysis apparatus and the gas phase side of the gas dissolution apparatus And a pure water supply pipe communicating with the liquid phase side of the gas dissolving device, and a gas dehumidifying device and a gas flow rate control device for controlling a gas supply amount into the gas dissolving device are sequentially provided in the gas supply pipe. An attached gas-dissolved water manufacturing apparatus,
A gas-dissolved water production apparatus comprising a water drop removing device in a gas supply pipe between the gas dehumidifying device and the gas flow rate control device. The apparatus for producing gas-dissolved water according to claim 1 , wherein the water droplet removing device is a gas filter. The gas-dissolved water production apparatus according to claim 1 or 2 , wherein the gas generated by electrolysis of water in the electrolyzer is hydrogen, oxygen, or ozone. It said gas flow control device, gas dissolved water production apparatus according to any one of claims 1 to 3, characterized in that a mass flow controller. The gas supply pipe, SUS, gas dissolved water production apparatus according to any one of claims 1 to 4, characterized in that a nylon or a fluorine-based resin. The gas dissolution apparatus, the internal by a gas permeable membrane according to any one of claims 1 to 5, characterized in that a gas permeable membrane module for gas dissolution which is partitioned into a liquid phase chamber and a gas phase chamber Gas dissolved water production equipment. Gas dissolved water is manufactured using the gas dissolved water manufacturing apparatus in any one of Claims 1-6 , The manufacturing method of the gas dissolved water characterized by the above-mentioned.

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