JPH08144078A - Gas-liquid separation device of water electrolyzer - Google Patents

Abstract

PURPOSE: To accurately detect liquid level by providing an introducing pipe for a liquid mixture and an optical sensor respectively in a 1st separating tank and the by-pass of a 2nd separating tank both of, which are connected with communicating pipes respectively for gas and liquid. CONSTITUTION: A gas-liquid separation device 20 in the oxygen side (in the same way as in hydrogen side) is constituted by the separation tank 21 and the separation tank 22, the tank 21 is communicated with the anode chamber by the introducing pipe 81 at the upper part of the tank 21 and a mixture of gas with liquid is fed from the anode chamber. The tank 21 and the tank 22 are connected with the gas introducing pipe 82 for oxygen in the upper part and the liquid introducing pipe 83 for pure water in the lower part, and the gaseous oxygen and the pure water which are gas- liquid separated in the tank 21 flow in the tank 22. In the tank 22, to control the liquid level of the liquid component separated in the tank 21, an optical sensor 60 for liquid level control is provided both at the position corresponding to upper limit and that corresponding to lower limit position on the outside of the by-pass passage 80 provided along the outside surface of the tank. As a result, bubbles causing error of the optical sensor detection are removed and the liquid level is surely detected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas-liquid separator used by connecting to a water electrolyzer of a high-purity oxygen / hydrogen generator, and more specifically, it is necessary in the technical fields such as electronics industry including semiconductor industry. The present invention relates to a gas-liquid separation device using an optical sensor for controlling the liquid level of a gas / liquid mixture generated when producing high-purity oxygen and hydrogen.

[0002]

2. Description of the Related Art High purity oxygen and hydrogen are used in all industrial fields.

For example, in the technical field of electronics industry, in the semiconductor manufacturing process, high-purity oxygen is used as an atmospheric gas during the oxide film formation process, and the atmosphere during heat treatment or vapor phase growth. High-purity hydrogen is used as the gas. Since the purity of such oxygen and hydrogen sometimes influences the quality of the product, high purity oxygen and hydrogen are required in the electronics industry, particularly in IC manufacturing.

This oxygen / hydrogen generator is disclosed in
No. 5-287570, for example, FIG.
As shown in FIG. 2, the hydrogen oxygen generator 2 includes a water electrolysis device 110 having a solid electrolyte membrane as a diaphragm, and gas-liquid separation devices 120, 130.
, And the dehumidifiers 140 and 150.
Here, the water electrolysis apparatus 110, as shown in FIG.
As the solid electrolyte membrane 110, a porous solid polymer electrolyte is used.
128, for example, a porous anode made of platinum group metal or the like on both sides of a cation exchange membrane (fluororesin sulfonic acid cation exchange membrane, for example, “Nafion 117” manufactured by DuPont)
A solid polymer electrolyte membrane 121 having a structure in which a cathode 122 and a cathode 123 are chemically bonded by electroless plating is used as a diaphragm.
Using a water electrolysis cell having a structure in which a cathode chamber 125 and a cathode chamber 125 are separated, electrolysis is performed while supplying pure water to the anode chamber 124 to generate oxygen gas from the anode chamber and hydrogen gas from the cathode chamber 125, respectively. By using this, electrolysis can be performed without adding any electrolyte substance or the like to pure water.

The generated hydrogen and oxygen are transported together with the supplied pure water in the form of a mixture of gas and liquid to separate gas-liquid separators 120 and 130, respectively.
In 120 and 130, gas and liquid are separated into gas and liquid components, pure water, which is a liquid component, is drained, and hydrogen and oxygen, which are gas components, remove moisture, so dehumidifiers 140, 150 composed of molecular sieves are used for dehumidification. And is supplied as purified gas.

By the way, in order to purify hydrogen and oxygen of higher purity, reliable detection and control of the liquid level in the gas-liquid separators 120 and 130 are essential conditions, and gas / liquid mixtures have been detected conventionally. , And as a control method, the optical sensor has various types and is inexpensive.
An optical sensor type liquid level control method is used because it has excellent characteristics. This is because a tank, which is a gas-liquid separation device, is connected to a bypass composed of a transparent member, and an optical sensor disposed outside the bypass causes the light emitted from the optical sensor to obstruct the liquid level of the gas / liquid mixture. The liquid level is measured by detecting an object.

[0007]

However, in the liquid level control method using the optical sensor as described above, the optical sensor is arranged outside the bypass connected to the separation tank, and the optical sensor is Two optical sensors, one for detecting the upper limit of the liquid level and the other for detecting the lower limit of the liquid level, are used outside the bypass. However, the gas / liquid mixture that is the object of control uses the bubbles generated by water electrolysis. Since the air bubbles are included, a problem that the optical sensor is erroneously detected as the liquid surface is likely to occur, and thus it is the current situation that accurate detection cannot be performed.

Therefore, there has been a demand for accurate and reliable liquid level control of a gas-liquid separator connected to a water electrolysis device of an oxygen / hydrogen generator using an inexpensive and high-performance optical sensor.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in order to achieve the above-mentioned problems and objects in the prior art, and has a simple device configuration and does not require complicated maintenance. Is a gas-liquid separator capable of reliably controlling the liquid level of a gas / liquid mixture, and includes the following (1) to
(3) is the gist of the configuration.

(1) Using the solid electrolyte membrane as a diaphragm,
The electrolytic cell was divided into an anode chamber and a cathode chamber, and pure water was electrolyzed while supplying pure water to the anode chamber, and oxygen gas was generated from the anode chamber and hydrogen gas was generated from the cathode chamber. A gas-liquid separator for use in a water electrolyzer to separate gas generated in the water electrolyzer from pure water, wherein the gas-liquid separator comprises a first separation tank and a second separation tank. The first separation tank is provided with an introduction pipe for a liquid mixture, which is connected in communication with the anode chamber or the cathode chamber of the water electrolysis device, and a gas is provided between the first separation tank and the second separation tank. A communication pipe for liquid and a communication pipe for liquid are connected to each other, and are connected to the outside of the second separation tank in order to detect the separation liquid level of the liquid component and the gas component which are gas-liquid separated in the second separation tank. A bypass path that communicates with the second separation tank and runs vertically While setting, the gas-liquid separator of a water electrolysis apparatus characterized by annexed light sensor for detecting the liquid level in the bypass path.

(2) The gas-liquid separator of the water electrolysis device according to (1) above, wherein two photosensors are provided above and below the bypass path.

(3) The water according to the above (2) is characterized in that the liquid level of the separation tank is controlled by guiding the detection information of the liquid level of the optical sensor to a control device. Gas-liquid separator for electrolyzer.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows the overall construction of an embodiment of an oxygen / hydrogen generator using the gas-liquid separators 20 and 30 of the present invention.

In the oxygen / hydrogen generator 1, pure water supplied from a pure water supply system (not shown) is electrolyzed by a solid electrolyte membrane to generate oxygen gas from the anode chamber and hydrogen gas from the cathode chamber, respectively. A water electrolysis device 10 for generating is provided. In this case, the structure of the water electrolysis device 10 is as shown in FIG.
Also, a structure similar to the structure of the conventional water electrolysis device 110 as shown in FIG. 4 may be used, but the structure is not limited to this.

On the anode side of the water electrolysis device 10 is connected a gas-liquid separator 20 for oxygen gas for gas-liquid separation of oxygen generated in the anode chamber of the water electrolysis device 10, while on the cathode side. A gas-liquid separator 30 for hydrogen gas is connected to separate the hydrogen generated on the cathode side of the water electrolysis device 10 into a liquid.

These gas-liquid separators 20 and 30 are composed of first separation tanks 21 and 31 and second separation tanks 22 and 32 communicating with them. In order to dehumidify the gas that has been gas-liquid separated by the separation tank that communicates with these two stages, for example, dehumidifiers 40 and 50 composed of molecular sieves are connected to the gas-liquid separators 20 and 30 on the oxygen and hydrogen sides, respectively. Has been done. The oxygen gas and hydrogen gas dehumidified by the dehumidifiers 40 and 50 are appropriately supplied to respective utilization facilities (not shown).

The detailed structure of these gas-liquid separators 20 and 30 will be described with reference to the schematic view of FIG.

The gas-liquid separation device 20 includes a first gas-liquid separation tank 21.
And a second gas-liquid separation tank 22. The liquid level control means for the gas / liquid mixture described above is provided on the oxygen side and the hydrogen side, respectively (for the sake of explanation, the gas-liquid on the oxygen side will be described below). Only the separation device 20 will be described, but the same applies to the gas-liquid separation device 30 on the hydrogen side, and reference numbers are added to FIG. 1).

A gas / liquid introduction pipe 81 is provided above the first separation tank 21 and communicates with the anode chamber of the water electrolysis device 10, and oxygen generated from the anode side of the water electrolysis device 10 and water are introduced. Pure water supplied to the anode chamber of the electrolysis device 10 is transported to the first gas-liquid separation tank 21 of the gas-liquid separation device 20 in a mixed state, that is, as a gas / liquid mixture through the introduction pipe 81. It has become so.

Further, between the first separation tank 21 and the second separation tank 22, a gas communication pipe 82 for oxygen extending from the upper part of the first separation tank 21 to the upper part of the second separation tank 22 is connected. Accordingly, the oxygen gas that has been gas-liquid separated in the first separation tank 21 is configured to flow into the second separation tank 22. Further, between the first separation tank 21 and the second separation tank 22, a pure water liquid communication pipe 83 extending from a lower portion of the first separation tank 21 to a lower portion of the second separation tank 22 is connected and provided. The pure water that has been gas-liquid separated in the first separation tank 21 is configured to flow into the second separation tank 22.

The second separation tank 22 includes the first separation tank 21.
To control the liquid level of the liquid components separated by
A U-shaped bypass path 80 is provided along the wall surface in the vertical direction of the tank. Optical sensors 60 (61, 62) for liquid level control are provided outside the bypass path 80, one at a position corresponding to the preset upper and lower limit positions of the liquid level in the separation tank. Has been done.

As a result, the upper and lower limits of the liquid level in the separation tank can be detected, and the liquid level can be controlled in cooperation with the liquid level control device 100.

In this case, it is preferable that the gas / liquid introduction pipe 81, the gas communication pipe 82 and the bypass passage 80 are arranged as follows.

That is, as shown in FIG. 5, the gas communication pipe 82 should be disposed at a position angularly displaced with respect to the gas / liquid introduction pipe 81, preferably at a position with an angle of 90 degrees. It is preferable that the bypass passage 80 is also arranged at an angularly displaced position with respect to the gas communication pipe 82, preferably at a position with an angle of 90 degrees.

The reason is that, when the gas / liquid introducing pipe 81, the gas communication pipe 82 and the bypass passage 80 are arranged in a straight line, respectively, the water / electrolysis device 10 is connected to the gas / liquid introducing pipe 81.
The gas / liquid mixture introduced into the first separation tank 21 via the second separation tank 22 directly passes through the gas communication pipe 82.
This is because there is a risk of invasion into the second separation tank 22, and air bubbles are generated in the second separation tank 22, which causes malfunction of the optical sensor.

Further, in the case of arranging in a straight line as described above, the gas / liquid mixture that has entered the second separation tank 22 through the gas communication pipe 82 is directly opened in the upper portion of the bypass passage 80. Therefore, there is a risk of intrusion, and bubbles are generated directly in the bypass 80, which also causes malfunction of the optical sensor.

Further, as described above, the gas / liquid introducing pipe 81,
Instead of arranging the gas communication pipe 82 and the bypass passage 80 at angularly displaced positions, the gas communication pipe 82 is connected to the gas / liquid introduction pipe 81 as a means for preventing malfunction of the optical sensor. It is also possible to dispose the bypass paths 80 with respect to the gas communication pipe 82 at different positions in terms of height, and further, in the disposition state in which they are angularly and vertically displaced as described above. It is also possible to

Further, as shown in FIG. 2, in order to maintain the liquid level of the separation tank at the liquid level position between the upper limit and the lower limit,
The liquid communication pipe 83 is branched in the middle, communicates with the drain pipe 85 via the air pellet valve 91 and the manual stop valve 92, and is configured so that the liquid level can be controlled as described later.

On the other hand, the upper surface of the second separation tank 22 is provided with a gas communication pipe 84 for oxygen gas which is connected to the dehumidifier 40 of FIG. 1 in order to remove water from oxygen in the second separation tank 22. Has been.

According to the liquid level detection of the optical sensors 61 and 62, a central processing unit (CPU
) Etc., the oxygen in the second separation tank 22 is adjusted by adjusting the flow rate adjusting valve (not shown) provided in the oxygen gas communication pipe 84. Meanwhile, the water is appropriately discharged from the drain pipe 85 by adjusting the air pellet valve 91.

As a preferable material for each member, in consideration of corrosion and prevention of mixing of impurities due to generation of particles, electrolytic polishing of stainless steel is followed by heat treatment in an oxidizing atmosphere to form a colored oxide film. It is preferable to use those which have been dissolved and removed (see JP-A-62-13563, JP-A-62-17184 (JP-B2-1916) and JP-A-2-14156).

In consideration of using an optical sensor, it is preferable to use a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), which is a transparent material having excellent weather resistance, for the bypass path.

The gas-liquid separation device thus constructed is used as follows.

First, oxygen generated from the anode side of the water electrolysis device 10 is transported to the first separation tank 21 through the gas / liquid introduction pipe 81 together with pure water supplied to the anode chamber of the water electrolysis device 10. It In this first separation tank 21, the gas / liquid mixture consisting of pure water and oxygen is continuously transferred to the second separation tank and separated into pure water and oxygen gas.

Oxygen gas-liquid separated in the first separation tank 21 is accumulated in the upper space of the first separation tank 21, while pure water is accumulated below the first separation tank 21. In this case, In the first separation tank 21, a large amount of air bubbles are still contained in the gas / liquid mixture.

Therefore, pure water is supplied from the liquid communication pipe 83 below the first separation tank 21, and oxygen gas is supplied to the first separation tank 21.
The upper gas communication pipe 82 is transported to the second separation tank 22 via different routes.

By the way, the oxygen gas and the pure water in the second separation tank 22 are separated by the first gas-liquid separation tank 21 into oxygen as a gas component and pure water as a liquid component,
Since they were transported by different routes (82, 83), they contain almost no bubbles.

These components separated in this way are separated from the bypass passage 80 provided in the second separation tank 21.
Will be partially introduced.

Since the boundary surface between the pure water and the oxygen gas in the bypass passage 80 has the same level as that of the pure water and the oxygen gas in the second separation tank, the light provided outside the bypass passage 80 is the same. The boundaries are detected by the sensors 61 and 62, and the detection result is introduced into the liquid level control device 90.

In this case, based on the detection result, the liquid level control device 90 instructs to open the air operated valve 91 of the drain pipe 85 when the boundary surface is detected at the position of the upper limit optical sensor 61. Drain the pure water, and the lower limit optical sensor 62
If the boundary surface is detected at the position of, the air operated valve 91 of the drain pipe 85 is closed to stop the drainage of pure water, the liquid components are accumulated in the first and second separation tanks 21 and 22, and The liquid level of the separation tank is maintained at the liquid level position between the upper limit and the lower limit.

[0042]

The action and effect of the invention The gas-liquid separation device according to the present invention is an extremely excellent invention having the following remarkable action and effect.

That is, since a variety of models are available, they are inexpensive, and a versatile optical sensor can be used for controlling the liquid level, it is simple and easy. By connecting the separation tank in two stages,
Since it is possible to expel air bubbles that cause the detection of the optical sensor to be erroneous, it is possible to reliably detect the liquid surface.

[Brief description of drawings]

FIG. 1 is a schematic view of an entire oxygen / hydrogen generator using a gas-liquid separator of the present invention.

FIG. 2 is a schematic view of a gas-liquid separation device of the present invention.

FIG. 3 is a schematic view of an entire conventional oxygen / hydrogen generator.

FIG. 4 is a schematic view of a conventional water electrolysis device.

FIG. 5 is a top view of the gas-liquid separation device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Oxygen / hydrogen generator 2 ... Oxygen / hydrogen generator 10 ... Water electrolysis device 20, 30 ... Gas-liquid separation device 21, 31 ... First separation tank 22, 32 ... Second separation tank 40, 50 ... Dehumidifier 60 , 70 ... Optical sensor 80, 90 ... Bypass path 81 ... Gas / liquid communication pipe 82 ... Gas communication pipe 83 ... Liquid communication pipe 84 ... Gas communication pipe 85 ... Drain pipe 100, 200 ... Control device 110 ... Water electrolysis device 120, 130 ... Gas-liquid separation device 121 ... Solid electrolyte membrane 122 ... Anode 123 ... Cathode 124 ... Anode chamber 125 ... Cathode chamber 128 ... Solid polymer electrolyte membrane 140, 150 ... Dehumidifier

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinichi Yasui 4-chome Nozoe, 108 Harima-cho, Kako-gun, Hyogo Prefecture Tawny SA202 (72) Hiroko Kobayashi 5-8-11 Nagura-cho, Nagata-ku, Hyogo Prefecture (72) Inventor Hiroyuki Harada 2-25-43 Nishioizumi, Nerima-ku, Tokyo

Claims (3)

[Claims] 1. A solid electrolyte membrane is used as a diaphragm to separate an electrolytic cell into an anode chamber and a cathode chamber, and pure water is electrolyzed while supplying pure water to the anode chamber to generate oxygen gas from the anode chamber. ,
A gas-liquid separation device for separating gas and pure water from a water electrolysis device into a liquid electrolysis device configured to generate hydrogen gas from a cathode chamber, wherein the gas-liquid separation is performed. The apparatus is composed of a first separation tank and a second separation tank, the first separation tank is provided with an introduction pipe for a liquid mixture which is connected in communication with the anode chamber or the cathode chamber of the water electrolysis apparatus, and the first separation tank is provided. A gas communication pipe and a liquid communication pipe are connected to each other between the tank and the second separation tank, and the separation liquid surface of the liquid component and the gas component separated in the second separation tank is separated into gas and liquid. For detection, a bypass path communicating with the second separation tank and extending in the vertical direction is provided outside the second separation tank, and an optical sensor for detecting the liquid level in the bypass path is attached. Of the water electrolysis device characterized by Gas-liquid separation device. 2. The gas-liquid separation device for a water electrolysis device according to claim 1, wherein two optical sensors are provided above and below a bypass path. 3. The water electrolysis apparatus according to claim 2, wherein the liquid level of the separation tank is controlled by guiding the detection information of the liquid level of the optical sensor to a control unit. Gas-liquid separation device.