KR102616663B1 - Reduced water production device and reduced water production method - Google Patents

Abstract

[Project] To provide a novel technology that can suppress the decrease in dissolved hydrogen molecule concentration in reduced water obtained by electrolytic reduction.
[Solution] An anode seal, a cathode seal, a diaphragm which is a fluorine-based ion exchange membrane disposed between the anode seal and the cathode seal, a porous anode electrode disposed in contact with the diaphragm in the anode seal, and a cathode electrode disposed in the cathode seal. supplying water between a diaphragm in an electrolytic cell and a cathode electrode, applying a current having an alternating current component with an average current value of 10 kHz or less to the cathode electrode, performing electrolytic reduction of water to generate hydrogen, and In relation to this, at least one of applying a current having a direct current component to perform electrolytic reduction of water to generate hydrogen and simultaneously applying mechanical vibration in the ultrasonic range of 30 kHz to 10 MHz to the surface of the cathode electrode is performed. A method for producing reduced water containing hydrogen.

Description

Reduced water production device and reduced water production method

The present invention relates to reduced water (hydrogen water) containing hydrogen obtained by electrolytic reduction, and particularly to an apparatus and method that can suppress a decrease in the concentration of dissolved hydrogen molecules in the reduced water.

Recently, businesses using hydrogen water have become active. Methods for generating hydrogen water include, for example, an electrolytic reduction method of electrolytically reducing water to directly generate dissolved hydrogen molecules in water, a method of bubbling hydrogen gas in water to dissolve hydrogen molecules, and a method of dissolving hydrogen molecules in water. A hydrogen gas pressure dissolution method for dissolving under pressure is known.

Under the conditions of atmospheric pressure and room temperature (20 to 28 degrees), the equilibrium theoretical solubility of hydrogen gas is 1.5 to 1.6 ppm.

Since the reduced water produced by electrolytic reduction is in contact with the atmosphere, the concentration of dissolved hydrogen molecules in the water is significantly lower than 1.5 ppm. For example, when electrolytically reduced water is stored in a plastic bottle, the concentration of dissolved hydrogen molecules in the water becomes 0.5 ppm or less after a certain period of time. In this way, when hydrogen water is stored in contact with the atmosphere, some of the dissolved hydrogen molecules volatilize into the atmosphere, thereby lowering the concentration of dissolved hydrogen molecules.

Therefore, for the purpose of suppressing a decrease in the concentration of dissolved hydrogen molecules in the obtained hydrogen water, the technique described in Patent Document 1, for example, has been proposed.

J.P. 2015-009175 A

New technologies are required to suppress the decline in dissolved hydrogen molecule concentration.

The purpose of the present invention is to provide a novel technology capable of suppressing a decrease in the concentration of dissolved hydrogen molecules in reduced water obtained by electrolytic reduction.

As a result of extensive research, the present inventors have found that when generating hydrogen by electrolysis, a predetermined current is applied to the cathode electrode in the electrolytic cell involved in the reduction reaction to proceed with electrolytic reduction, or by advancing electrolytic reduction, the electrolytic reduction is carried out near the cathode electrode. It was discovered that a decrease in the concentration of dissolved hydrogen molecules could be suppressed by generating hydrogen and simultaneously applying vibration by predetermined ultrasonic waves to the cathode electrode, thereby completing the present invention.

That is, the gist of the present invention is as follows.

[1] An anode chamber, a cathode chamber, a diaphragm that is a fluorine-based ion exchange membrane disposed between the anode chamber and the cathode chamber, a porous anode electrode disposed in contact with the diaphragm in the anode chamber, and a porous anode electrode disposed in the cathode chamber. An electrolyzer having a cathode electrode,

Applying a current having an alternating current component with a current average value of 10 kHz or less to the cathode electrode of zero or more to perform electrolytic reduction of water supplied between the diaphragm and the cathode electrode to generate hydrogen, and generating hydrogen to the cathode electrode. By applying a current having a direct current component, electrolytic reduction of water supplied between the diaphragm and the cathode electrode is performed to generate hydrogen, and at the same time, mechanical vibration in the ultrasonic range of 30 kHz to 10 MHz is applied to the surface of the cathode electrode. A reduced water production device comprising a concentration drop suppression unit that performs at least one of the following:

[2] In the device described in [1] above,

A reduced water production device in which the current having an alternating current component whose average current value of 10 kHz or less is equal to or greater than zero is a current having an alternating current component whose minimum current value is equal to or greater than zero.

[3] In the device described in [1] or [2] above,

A reduced water production device in which the current having an alternating current component with an average current value of 10 kHz or less equal to or greater than zero is half-wave rectified or full-wave rectified alternating current.

[4] In the device according to any one of [1] to [3] above,

The concentration drop suppressor performs electrolytic reduction of water by applying a half-wave rectified or full-wave rectified alternating current of 10 kHz or less to the cathode electrode, and at the same time applies an ultrasonic wave in the ultrasonic range of 30 kHz to 10 MHz to the surface of the cathode electrode. A reduced water production device that imparts mechanical vibration.

[5] In the device according to any one of [1] to [4] above,

A reduced water production device in which an ion exchange resin is filled between the diaphragm and the cathode electrode.

[6] In the device described in [5] above,

The concentration drop suppressing section includes an ultrasonic vibrator embedded in the ion exchange resin,

The reduced water production device wherein the concentration drop suppressing unit applies mechanical vibration in an ultrasonic range of 30 kHz to 10 MHz from an electric ultrasonic vibrator to the surface of the cathode electrode.

[7] In the device according to any one of [1] to [4] above,

The cathode seal has a plurality of protrusions on a surface facing the diaphragm, and the cathode electrode is disposed to contact the protrusions at the tip of the protrusions, and a direction straight to the diaphragm between the cathode electrode and the diaphragm A reduced water production device wherein the distance is 1 mm or less.

[8] In the device described in [7] above,

The cathode electrode is a porous cathode electrode,

The cathode chamber has a plurality of raw water supply parts that introduce water into the cathode chamber, and a plurality of reduced water discharge parts that discharge electrolytically reduced water from the cathode chamber, and the raw water supply part and the reduced water discharge part are A reduced water production device arranged with a protrusion interposed therebetween.

[9] In the device according to any one of [1] to [8] above,

The electrolytic cell is a three-chamber electrolytic cell including the anode chamber, the cathode chamber, and an intermediate chamber disposed between the anode chamber and the cathode chamber and dividing the anode chamber and the cathode chamber by the diaphragm, and in the intermediate chamber A reduced water production device in which a reducing substance is present.

[10] An anode chamber, a cathode chamber, a diaphragm that is a fluorine-based ion exchange membrane disposed between the anode chamber and the cathode chamber, a porous anode electrode disposed in contact with the diaphragm in the anode chamber, and a porous anode electrode disposed in the cathode chamber. Supplying water between the diaphragm and the cathode electrode in an electrolytic cell having a cathode electrode,

Electrolytic reduction of water is performed to generate hydrogen by applying a current having an alternating current component with a current average value of 10 kHz or less equal to or greater than zero to the cathode electrode, and electrolysis of water by applying a current having a direct current component to the cathode electrode. A method for producing reduced water containing hydrogen, comprising performing at least one of performing reduction to generate hydrogen and simultaneously applying mechanical vibration in an ultrasonic range of 30 kHz to 10 MHz to the surface of the cathode electrode. .

[11] In the method described in [10] above,

A method for producing reduced water, wherein the current having an alternating current component whose current average value of 10 kHz or less is equal to or greater than zero is a current having an alternating current component whose lowest current value is equal to or greater than zero.

[12] In the method described in [10] or [11] above,

A method for producing reduced water, wherein the current having an alternating current component with an average current value of 10 kHz or less equal to or greater than zero is half-wave rectified or full-wave rectified alternating current.

[13] In the method according to any one of [10] to [12] above,

Electrolytic reduction of water is performed by applying a half-wave rectified or full-wave rectified alternating current of 10 kHz or less to the cathode electrode, and at the same time applying mechanical vibration in the ultrasonic range of 30 kHz to 10 MHz to the surface of the cathode electrode. , Method for producing reduced water.

[14] In the method according to any one of [10] to [13] above,

A method for producing reduced water, wherein an ion exchange resin is filled between the diaphragm and the cathode electrode.

[15] In the method described in [14] above,

A method for producing reduced water, wherein mechanical vibration in an ultrasonic range of 30 kHz to 10 MHz is applied to the surface of the cathode electrode, and the mechanical vibration is applied from an ultrasonic transducer embedded in the ion exchange resin.

[16] In the method according to any one of [10] to [13] above,

The cathode seal has a plurality of protrusions on a surface facing the diaphragm, and the cathode electrode is arranged to contact the protrusions at the tip of the protrusions, and a direction straight to the diaphragm between the cathode electrode and the diaphragm. A method for producing reduced water, wherein water is supplied between the diaphragm and the cathode electrode in the electrolytic cell where the distance is 1 mm or less.

[17] In the method described in [16] above,

The cathode electrode is a porous cathode electrode,

The cathode chamber has a plurality of raw water supply parts that introduce water into the cathode chamber, and a plurality of reduced water discharge parts that discharge electrolytically reduced water from the cathode chamber, and the raw water supply part and the reduced water discharge part are A method for producing reduced water, which is disposed with a protrusion interposed therebetween.

[18] In the method according to any one of [10] to [17] above,

The electrolytic cell is a three-chamber electrolytic cell including the anode chamber, the cathode chamber, and an intermediate chamber disposed between the anode chamber and the cathode chamber and dividing the anode chamber and the cathode chamber by the diaphragm, and in the intermediate chamber A method for producing reduced water in which a reducing substance is present.

According to the present invention, it is possible to provide a novel technology capable of suppressing a decrease in the concentration of dissolved hydrogen molecules in reduced water obtained by electrolytic reduction.

1 is a diagram showing an outline of a system according to a first embodiment.
Figure 2 is a diagram showing the outline of an electrolytic cell according to the second embodiment.
Figure 3 is a diagram showing an outline of a system according to the second embodiment.
4 is a diagram showing an outline of an electrolytic cell according to the second embodiment.
Figure 5 is a diagram showing an outline of a system according to the third embodiment.
Figure 6 is a diagram showing the outline of an electrolytic cell according to the fourth embodiment.
Figure 7 is a diagram showing the outline of an electrolytic cell according to the fourth embodiment.
Fig. 8 is a diagram showing an outline of a system according to the fifth embodiment.
9 is a diagram showing an outline of an electrolytic cell according to another embodiment.
10 is a diagram showing an outline of a system according to another embodiment.
Figure 11 is a graph regarding the amount of hydrogen molecules dissolved (equilibrium value) under atmospheric pressure and room temperature.
Figure 12 is a diagram schematically showing the vicinity of the cathode electrode surface.
Figure 13 is a graph showing the amount and size of hydrogen molecule bubbles generated by half-wave rectified electrolysis current.

[First Embodiment]

Next, one embodiment of the present invention will be described.

The first embodiment includes an anode chamber, a cathode chamber, a diaphragm that is a fluorine-based ion exchange membrane disposed between the anode chamber and the cathode chamber, a porous anode electrode disposed in contact with the diaphragm in the anode chamber, and a cathode electrode disposed in the cathode chamber. An electrolytic cell comprising an electrolytic cell, and a concentration reduction suppressor that applies a current having an alternating current component with an average current value of 10 kHz or less to the cathode electrode to perform electrolytic reduction of water supplied between the diaphragm and the cathode electrode to generate hydrogen. It relates to a reduced water production device.

First, the configuration of the system according to the first embodiment will be described.

Figure 1 is a diagram showing an outline of the configuration of the system.

The system according to the first embodiment includes an electrolyzer 100 and a raw material water generation liquid delivery unit 200 that supplies raw water to the cathode chamber 3 of the electrolytic tank 100. In addition, from the viewpoint that the produced reduced water (hydrogen water) is more preferable for drinking, the following description takes the case of supplying water with a conductivity of 200 μS/cm or less to the electrolyzer 100 as an example. It is not limited to.

In the first embodiment, the raw material water generation liquid delivery unit 200 may be composed of a reverse osmosis membrane filter 140 and a water pump 130. The reverse osmosis membrane filter 140 improves the purity of tap water delivered from the tap water line 150, and uses water with a conductivity of 200 μS/cm or less (hereinafter also referred to as raw water. It is more preferable to use water with a conductivity of 20 μS/cm or less. It is called). The water pump 130 supplies the raw material water generated in the reverse osmosis membrane filter 140 to the cathode chamber 3 provided in the electrolytic cell 100.

In addition, the water pump 130, reverse osmosis membrane filter 140, and water line 150 may be known and are not particularly limited. In addition, the configuration of the raw material water generating unit 200 is an example, and the raw material water may be supplied to the electrolytic tank 100 by another configuration.

The electrolytic cell 100 can be, for example, a two-chamber electrolytic cell described in Patent Document 1. Specifically, the electrolytic cell 100 is configured to include an anode chamber 1 and a cathode chamber 3. A diaphragm 5, which is a fluorine-based ion exchange membrane, is disposed between the anode seal 1 and the cathode seal 3, and separates the anode seal 1 and the cathode seal 3. Additionally, a porous anode electrode 21 is disposed in the anode chamber 1, and a cathode electrode 4 is disposed in the cathode chamber 3. The porous anode electrode 21 is disposed in the anode chamber 1 at a position in contact with the diaphragm 5 . Additionally, the cathode electrode 4 is arranged to form a wall portion facing the diaphragm 5 of the cathode chamber 3. In addition, in the first embodiment, water with a conductivity of 200 μS/cm or less (preferably water with a conductivity of 20 μS/cm or less) is preferably used between the diaphragm 5 of the cathode chamber and the cathode electrode 4. As a structure, ion exchange resin 31 is filled.

In addition, regarding the respective capacities of the anode chamber 1 and the cathode chamber 3, the material and size of the porous anode electrode 21 and the cathode electrode 4, and the size and number of holes in the porous anode electrode 21, etc. There is no particular limitation, and a person skilled in the art can set it appropriately.

Additionally, voltage is applied to the anode electrode 21 and the cathode electrode 4 by supplying current from the power source 110. As a result, electrolysis of water is performed in the electrolytic cell 100, and a reduction reaction proceeds in the cathode chamber 3 to generate hydrogen. On the other hand, an oxidation reaction is performed in the anode chamber 1 (since a known configuration can be used, detailed description and illustration are omitted).

Reduced water containing hydrogen generated in the cathode chamber 3 of the electrolytic cell 100 is sent to the storage tank 120 and stored. The inflow into the water storage tank 120 can be controlled by the valve 160. Additionally, it is possible to configure the pressure state within the cathode chamber 3 to be controlled by operating the valve 160.

In the first embodiment, a current having an alternating current component with an average current value of 10 kHz or less equal to or greater than zero is supplied to the cathode electrode 4 from the power source 110 (corresponding to the concentration drop suppression unit in the first embodiment). It performs electrolytic reduction of water and generates hydrogen. Specifically, a half-wave rectified or full-wave rectified alternating current of 10 kHz or less is applied to the cathode electrode 4 to electrolytically reduce water and generate hydrogen.

Here, half-wave rectification and full-wave rectification refer to processing that converts the negative current/voltage component of alternating current/voltage into the positive side of zero or greater than zero.

In addition, the current having an alternating current component with a current average value of zero or more is not limited to half-wave rectified or full-wave rectified alternating current, and may be, for example, a pulse current. On the other hand, because of the high cost, it is preferable to apply a half-wave rectified or full-wave rectified alternating current of 10 kHz or less to perform electrolytic reduction of water to generate hydrogen.

In this way, in the first embodiment, the water supplied to the cathode chamber is electrolytically reduced by applying a current having an alternating current component with an average current value of 10 kHz or less to the cathode electrode of zero or more, so that the dissolved hydrogen molecule concentration is higher than the equilibrium value. there is. As a result, it becomes possible to suppress the decrease in dissolved hydrogen molecule concentration.

[Second Embodiment]

Next, the second embodiment will be described. Parts that are common to the first embodiment are given the same reference numerals and descriptions are omitted.

Figure 2 is a diagram showing the configuration of a system according to the second embodiment. The system according to the second embodiment includes an electrolyzer 100, a raw material water generation liquid delivery unit 200, a power source 110, and a water storage tank 120, similar to the first embodiment. Additionally, the system according to the second embodiment includes a mechanical vibration imparting unit 8 that applies mechanical vibration to the surface of the cathode electrode 4 within the cathode chamber 3. In the second embodiment, a current having a direct current component is applied to the cathode electrode 4 to perform electrolytic reduction of water in the cathode chamber 3 to generate hydrogen, and at the same time, the mechanical vibration applying unit 8 causes the cathode chamber to be electrolytically reduced. Mechanical vibration in the ultrasonic range of 30 kHz to 10 MHz is applied to the surface of the cathode electrode 4 in (3). Therefore, in the second embodiment, the power source 110 and the mechanical vibration applying unit 8 correspond to the concentration drop suppressing unit.

In addition, the current applied to the cathode electrode 4 is not particularly limited as long as it is a current having a direct current component, and may be a direct current other than the half-wave rectified or full-wave rectified alternating current of 10 kHz or less in the first embodiment. On the other hand, from the viewpoint of further suppressing the decrease in dissolved hydrogen molecule concentration, it is preferable that the current applied to the cathode electrode 4 is a half-wave rectified or full-wave rectified alternating current of 10 kHz or less. Figure 2 illustrates the case of applying half-wave rectified or full-wave rectified alternating current of 10 kHz or less.

The mechanical vibration imparting unit 8 may use, for example, an ultrasonic vibrator. The position where the mechanical vibration imparting portion 8 is placed is not particularly limited and can be set appropriately, but can be placed at the position shown in Figs. 3 and 4, for example.

In FIG. 3 , the mechanical vibration applying portion 8 is disposed outside the electrolytic cell 100 at a position in contact with the cathode electrode 4. In Fig. 4, the mechanical vibration imparting portion 8 is embedded in the ion exchange resin 31 in the cathode chamber 3 and is disposed near the surface of the cathode electrode 4. 2 illustrates the case where the mechanical vibration imparting portion 8 is embedded in the ion exchange resin 31 within the cathode chamber 3.

Among these, the dissolved hydrogen concentration can be further improved by applying mechanical vibration directly to the surface of the cathode electrode 4, so it is preferable that the mechanical vibration applying unit 8 is installed inside the cathode chamber as illustrated in FIG. 4. do.

In this way, in the second embodiment, electrolytic reduction of water in the cathode chamber is performed to generate hydrogen, and at the same time, the mechanical vibration imparting unit 8 generates a voltage of 30 kHz or more on the surface of the cathode electrode 4 in the cathode chamber 3. By applying mechanical vibration in the ultrasonic range of MHz or less, the dissolved hydrogen molecule concentration can be made higher than the equilibrium value. As a result, it becomes possible to suppress a decrease in the concentration of dissolved hydrogen molecules in the reduced water.

[Third Embodiment]

Next, the third embodiment will be described.

Parts that are common to the first embodiment are given the same reference numerals and descriptions are omitted.

Fig. 5 shows an outline of the system according to the third embodiment.

The system according to the third embodiment has a three-chamber electrolyzer 300 instead of the two-chamber electrolyzer 100 according to the first embodiment. The three-chamber electrolytic cell 300 is disposed between the anode chamber 1 and the cathode chamber 3 in addition to the anode chamber 1 and the cathode chamber 3, and the anode chamber is separated by the diaphragms 51 and 52. An intermediate thread (6) is provided between (1) and the cathode thread (3). In addition, as in the case of the first embodiment, in the third embodiment, the electrolytic cell 300 can be, for example, a three-chamber electrolytic cell described in Patent Document 1. The intermediate chamber (6) is filled with an ion exchange resin, and purified water containing alkaline earth metals such as calcium ions and removing bivalent or higher metal ions can be supplied (as in the case of the anode chamber (1), the intermediate chamber (6) is filled with an ion exchange resin. Since a known configuration can be used for the thread 6, detailed description and illustration are omitted).

By providing the intermediate chamber (6), it becomes possible to prevent oxidizing substances such as oxygen generated in the anode chamber (1) from transferring to the cathode chamber (3).

[Fourth Embodiment]

Next, the fourth embodiment will be described. Parts in common with the second embodiment are given the same symbols and description is omitted.

6 and 7 are diagrams showing an outline of the electrolytic cell 300 according to the fourth embodiment. In the fourth embodiment, as in the second embodiment, the position where the mechanical vibration imparting portion 8 is placed is not particularly limited and can be set appropriately, for example, it can be placed at the position shown in FIGS. 6 and 7. You can.

In FIG. 6 , the mechanical vibration applying portion 8 is disposed outside the electrolytic cell 300 at a position in contact with the cathode electrode 4. In Fig. 7, the mechanical vibration imparting portion 8 is embedded in the ion exchange resin 31 in the cathode chamber 3 and is disposed near the surface of the cathode electrode 4.

[Fifth Embodiment]

Next, the fifth embodiment will be described. Parts that are common to the third and fourth embodiments are given the same reference numerals and descriptions thereof are omitted.

In the fifth embodiment, in order to further suppress the decrease in dissolved hydrogen molecule concentration, an organic acid reducing substance is present in the middle chamber 6 of the three-chamber electrolytic cell 300. As a result, the cathode water becomes slightly acidic, and thus the decrease in the concentration of dissolved hydrogen molecules can be further suppressed.

Fig. 8 shows an outline of the system according to the fifth embodiment.

In the fifth embodiment, the organic acid reducing aqueous solution is passed through the intermediate chamber 6, and the reducing aqueous solution discharged from the outlet of the intermediate chamber 6 is guided to the intermediate chamber 6 to circulate the reducing aqueous solution, thereby reducing the organic acid. The aqueous solution is filled into the intermediate chamber (6). As a result, the reducing substance exists in the intermediate chamber 6.

In the fifth embodiment, a circulation line 190 is provided to circulate the organic acid reducing aqueous solution. An intermediate chamber liquid circulation pump 180 and an intermediate chamber liquid storage tank 170 are installed in this circulation line 190 to circulate the reducing aqueous solution.

Examples of organic acid-reducing substances include ascorbic acid, lactic acid, and gluconic acid, and in the present embodiment, their aqueous solutions can be circulated.

[Other embodiments]

As described above, the present invention has been described with reference to several embodiments, but it is also possible to use other embodiments.

For example, in the first to fifth embodiments, as a preferred configuration for reduction using water with a conductivity of 200 μS/cm or less, the electrolytic cell is a cathode chamber in which an ion exchange resin is filled between the cathode electrode and the diaphragm. It has a configuration. Instead of this, another configuration may be used.

For example, an improved cathode electrode that enables both water passage and low-voltage electrolysis without filling an ion exchange resin can be used. Specifically, the cathode seal has a plurality of protrusions on the surface facing the diaphragm, and the cathode electrode is disposed so as to contact the protrusions at the tip of the protrusions, and in the direction perpendicular to the diaphragm between the cathode electrode and the diaphragm. The distance can be made to be less than 1 mm. Examples of such cathode seals include, specifically, a cathode electrode having a wave-shaped surface described in Patent Document 1, and a cathode seal provided with a comb-shaped cathode electrode.

Additionally, an example of the above-described reduced water production device in which the distance between the cathode electrode and the diaphragm in the direction perpendicular to the diaphragm is 1 mm or less includes a reduced water production device having a cathode seal frame as described below.

Figure 9 is a diagram showing an outline of an electrolyzer according to the relevant aspect, and Figure 10 is a diagram showing an outline of the system according to the relevant aspect.

As shown in FIG. 9, in the reduced water production device of this aspect, a porous cathode electrode 4 having a plurality of openings is disposed in contact with the cathode seal frame 400, and the porous cathode electrode 4 and the diaphragm ( 5) The distance in the direction going straight to the diaphragm 5 is set to 1 mm or less. Specifically, the cathode seal frame 400 has a plurality of protrusions 320 on the surface opposite to the diaphragm 5, and the porous cathode electrode 4 has a protrusion ( 320) and is disposed to face the diaphragm 5 at the same time.

In addition, on the surface of the cathode seal frame 400 facing the porous cathode electrode 4, a non-protruding portion that is not in contact with the cathode electrode 4 is provided with a plurality of raw water supply lines 302 and a plurality of reduced water supply lines 302. The discharge line 303 is connected, and the raw material water supply line 302 and the reduced water discharge line 303 are disposed with a protrusion 320 in contact with the porous cathode electrode 4 interposed therebetween.

The raw material water supply line 302 is connected to the raw material water supply manifold 304. Raw material water is supplied to the raw material water supply manifold 304 from a communicating raw material water inlet 306. Raw material water flows into the cathode chamber 3 from the raw material water supply line 302 via the raw material water supply manifold 304, and is in a non-contact portion with the protrusion 320 of the porous cathode electrode 4. It is supplied to the electrolytic surface 301 on the surface of the porous cathode electrode 4 through the opening.

Additionally, the reduced water discharge line 303 communicates with the manifold 305 for discharge of reduced water. The reduced water generated on the electrolyte surface flows into the reduced water discharge manifold 305 through the opening in the non-contact portion with the protrusion 320 of the porous cathode electrode 4 and the reduced water discharge line 303. The reduced water outlet 307 is connected to the reduced water discharge manifold 305, and the reduced water produced is discharged from the reduced water outlet 307. In addition, in the exemplified embodiment, in the cross section where the raw material water supply line 302 and the raw material water supply manifold 304 can be seen, the reduced water discharge line 303 and the reduced water discharge manifold 305 cannot admit. Therefore, in Figs. 9 and 10, the reduced water discharge line 303 and the reduced water discharge manifold 305 are indicated by broken lines.

That is, in this aspect, the raw material water flowing into the cathode chamber from the raw material water supply line 302 is supplied to the electrolytic surface 301 through the opening in the non-contact portion with the protrusion 320 of the porous cathode electrode 4. do. In addition, the reduced water generated on the electrolytic surface 301 is discharged outside the cathode chamber from the reduced water drain line 303 through an opening in the non-contact portion with the protruding portion 320 of the porous cathode electrode 4. According to this aspect, the flow velocity on the surface of the cathode electrode, which is the electrolytic surface, can be increased. As a result, water with a high concentration of dissolved hydrogen molecules in the vicinity of the cathode electrode can be more efficiently transferred to bulk water, and thus a decrease in the concentration of dissolved hydrogen molecules can be further suppressed.

[Given vibration to cathode electrode]

As shown in Figure 11, under conditions of room temperature and atmospheric pressure, the equilibrium theoretical solubility of hydrogen gas is 1.5 to 1.6 ppm.

As a result of extensive research, the present inventor has found that when electrolysis is performed to generate hydrogen, electrolytic reduction is carried out by applying a current having an alternating current component with a current average value of zero or more to the cathode electrode in the electrolytic cell involved in the reduction reaction, or by applying direct current. By applying a current having a component to the cathode electrode to proceed with electrolytic reduction to generate hydrogen near the cathode electrode, and at the same time applying vibration by a predetermined ultrasonic wave to the cathode electrode, a decrease in the concentration of dissolved hydrogen molecules can be suppressed. We found what existed and completed the present invention. Hereinafter, this point will be explained in detail.

Regarding the generation of hydrogen and hydrogen molecule bubbles on the surface of the cathode electrode when electrolysis is performed using an electrolytic cell, the existence state and dissolution process of saturated hydrogen on the surface of the cathode electrode have been analyzed by Saibara et al. Yasuhiro Bara, Matsushita Denko Co., Ltd., Trial Youth Implementation Report, August 12, 2003.

In bulk water, the dissolved hydrogen concentration is below the equilibrium theoretical value, but the dissolved hydrogen concentration on the surface of the cathode electrode during electrolysis is above the equilibrium value. In addition, the diameter of the hydrogen gas is nm in the initial stage, but as time passes, tiny hydrogen gases coalesce with each other, and the size of the hydrogen gas increases.

Figure 12 shows the state of hydrogen gas generated on the cathode electrode surface. Generally, the interface layer of an aqueous solution consists of a Helmholtz layer (10) and an electric double layer (diffusion layer) (9). The Helmholtz layer 10 is divided into an inner Helmholtz layer and an outer Helmholtz layer. When water is supplied and an aqueous solution excluding ions, etc. is used, the main molecules in the Helmholtz layer 10 are water molecules, which are solvent molecules. Water molecules, H ₂ O, which are solvent molecules, undergo reductive decomposition according to the following reaction equation, and hydrogen molecules are generated. As a result, hydrogen molecules become the main molecules of the Helmholtz layer 10.

Anode electrode: 2H ₂ O → O ₂ +4H ⁺ +4e ^-

Cathode electrode: 2H ⁺ +2e ^- → H ₂

For example, as illustrated in FIG. 12, hydrogen molecules or hydrogen molecule bubbles 11 of extremely small diameter (nm) generated in the Helmholtz layer 10 move to the electric double layer 9. becomes a hydrogen molecular bubble 13 having a larger diameter, and as the distance from the cathode electrode 4 becomes farther, the hydrogen molecular bubble 12 becomes larger than the hydrogen molecular bubble 13. In this dynamic process, the dissolved hydrogen concentration is expected to be greater than the value from an equilibrium theoretical perspective.

Here, the amount of hydrogen gas generated when electrolyzed at a current density of 0.2 A/cm2 is simply calculated. Assuming that 1㎛ of the cathode electrode surface per unit area is electrolyzed under these conditions, about 800 ppm of hydrogen molecules will be generated in the cathode electrode surface layer. Assuming that hydrogen molecules are dissolved at this concentration, and based on the experiment of A.H.Pray et al. (H.A. PRAY et al., IN DUSRIAL AND ENGI NEERING CHEMISTRY Vol. 44, No. 5, 1146), on the surface of the cathode electrode The value when the dissolved hydrogen molecule concentration is converted to pressure is assumed to be about 1000 HPa or more. In other words, it is a phenomenon of dissolution of hydrogen gas under high pressure of about 1000 HPa or more. In this way, since the cathode electrode surface during the electrolytic reaction is in a non-equilibrium state, it is clear that the dissolved hydrogen molecule concentration is decomposing from the equilibrium value. The present invention relates to a method of effectively utilizing the dissolved hydrogen molecules on the surface of the cathode electrode in this non-equilibrium state.

Additionally, a report by Saibara et al. describes that hydrogen gas with a size of 200 nm was observed on the surface of the cathode electrode. It has been reported that when the size of hydrogen gas is 200 nm or less, it becomes uniformly transparent to the naked eye, and the stability of hydrogen gas in electrolyzed water is improved. This stability is important in terms of the lifetime of the hydrogen gas residue in developing the business of water in which hydrogen molecules are dissolved.

The present inventor generates reduced water by making the dissolved hydrogen molecule concentration higher than the equilibrium concentration value, and efficiently transfers the dissolved hydrogen molecule concentration water near the cathode electrode to bulk water in order to suppress the decrease in dissolved hydrogen molecule concentration. It was conceived. The present invention relates to a method of efficiently transferring water with a high concentration of dissolved hydrogen molecules in the vicinity of a cathode electrode into bulk water by adding a dynamic action to the surface of the cathode electrode.

Specifically, the dissolved hydrogen concentration in reduced water can be improved by any of the methods shown below (1) and (2).

(1) Ultrasound application

The Helmholtz layer and the electric double layer (diffusion layer) are stirred by ultrasonic vibration, and this stirring causes small-diameter hydrogen gas bubbles in the Helmholtz layer to move to the electric double layer (diffusion layer), and small-diameter hydrogen gas bubbles in the electric double layer (diffusion layer) are stirred by ultrasonic vibration. Gas bubble concentration is improved. As a result, the concentration of small-diameter hydrogen gas in bulk water increases, and the dissolved hydrogen concentration in the obtained reduced water also improves.

(2) Application of electrical vibration (fluctuating electrolytic current)

This method improves the concentration of dissolved hydrogen in reduced water by applying a current having an alternating current component with a current average value of zero or more to the cathode electrode.

In this method, a constant electrolytic current is not applied, but a period during which the electrolytic current is zero is provided. A graph illustrating an example of current application and generated hydrogen gas according to the method is shown in FIG. 13. FIG. 13 is a graph corresponding to the case where a half-wave rectified current is applied to the cathode electrode in Experimental Example 1 described later. In FIG. 13, the half-wave rectified current is applied to the cathode electrode as indicated by the dotted line current value. In response to this change in current, large bubbles of hydrogen gas (larger than 1 μm) are generated. When electricity is applied, small hydrogen gas bubbles (1 μm or less) are always supplied, so hydrogen gas bubbles of large diameter are generated. When water is passed to the electrode surface, large-diameter hydrogen gas is removed. However, since the flow rate is greatly reduced in the interface layer of the Helmholtz layer and the electric double layer, small-diameter hydrogen gas partially remains. When power is not applied, the growth of gas stops, making it possible to remove only small diameter hydrogen gas. As a result, hydrogen gas with a smaller diameter remains in the reduced water than the hydrogen gas removed when the current is not applied, thereby increasing the dissolved hydrogen concentration. Furthermore, in order to further increase the dissolved hydrogen concentration, it is preferable to increase the pressure inside the cathode chamber, and specifically, it is preferable to set the pressure in the cathode chamber to 0.01 to 0.1 kg/cm2.

The above explanation indicates that alternating current is preferable to increase the dissolved hydrogen concentration. However, what must be taken care of here is that since the target is the cathode electrolytic reaction, if a normal alternating current is used in alternating current, the anode reaction is mixed, making it difficult to increase the concentration of dissolved hydrogen molecules. Therefore, even if the cathode electrolysis current is the lowest, it is necessary to lower the value of the electrolysis current to a value at which large-diameter hydrogen gas bubbles are difficult to observe with the naked eye. Specifically, a current having an alternating current component whose current average value is equal to or greater than zero can be applied to the cathode electrode, preferably a current having an alternating current component whose minimum current value is equal to or greater than zero, and more preferably a half-wave rectified or full-wave rectified alternating current. is given to the cathode electrode. Therefore, for example, a rectified alternating current power source or a pulse power source can be used as a power source of current having an alternating current component whose current average value is zero or more.

Since the present invention focuses on the efficient movement of hydrogen gas bubbles, there is a limit regarding the upper frequency limit. In general, when measuring the frequency dependence of phenomena accompanying mass transfer, the effect of alternating current or pulse current appears on electrolysis in the region of about 10 kHz or less.

[Experimental Example 1]

A system based on the first embodiment described above was constructed.

As the reverse osmosis membrane filter 140, a reverse osmosis membrane filter manufactured by Seemsbionics was used. Direct current power or 50Hz alternating current power was used as the power source. The comparison was made using alternating current as unrectified, full-wave rectified, or half-wave rectified. Additionally, the size of the electrolytic cell was set to 6 × 8 × approximately 1 cm for both the anode and cathode chambers. The external dimension of the electrode was 8 × 6 cm2 (material: platinum plating on a titanium plate). The anode electrode was a porous anode electrode in which 130 holes of 6 mm phi were drilled at equal intervals. The electrolysis current was set to 4A. The current density is 0.83m A/cm2.

The concentration of dissolved hydrogen molecules in reduced water was measured using methylene blue reagent.

The results are shown in Table 1.

When electrolysis was carried out at the same current value, when direct current was used, the dissolved hydrogen concentration value did not exceed about 1.5 ppm from an equilibrium theoretical perspective. However, when full-wave rectified or half-wave rectified current was applied, it became possible to obtain a measured value of the dissolved hydrogen molecule concentration exceeding the equilibrium value. This result shows that it is possible to generate dissolved hydrogen molecule concentration water exceeding the equilibrium value by using the electrolytic cell and electrolytic conditions of the present invention.

[Experimental Example 2]

In this Experimental Example 2, the effect of mechanical vibration on the concentration of dissolved hydrogen molecules is explained.

A vibration device of approximately 250 Hz (manufactured by WILD ONE) and an ultrasonic oscillator of approximately 2.1 MHz (HM2412(C), Honda Electronics Co., Ltd.) were used. The basic system configuration is the same as Experimental Example 1. The method of applying mechanical vibration to the cathode electrode surface was as follows. In the case of low-frequency mechanical vibration of about 250 Hz as a control, a vibration device was placed outside the electrolyzer at a position in contact with the cathode electrode, and vibration was applied from the outside of the electrolyzer. In the case of ultrasonic vibration of about 2.4 MHz, two structures in Figures 3 and 4 were examined for a two-chamber electrolyzer. That is, as shown in FIG. 3, an ultrasonic vibrator is attached to a position in contact with the cathode electrode outside the electrolytic cell, and as shown in FIG. 4, the ultrasonic vibrator is embedded in an ion exchange resin near the surface of the cathode electrode in the cathode chamber. Ready to install.

The results are shown in Tables 2 and 3. As shown in Tables 2 and 3, low-frequency mechanical vibration (about 250 Hz) had no effect in increasing the dissolved hydrogen concentration. Using direct current power and ultrasonic vibration (approximately 2.4 MHz), a transient concentration of dissolved hydrogen molecules of 1.8 ppm was measured, resulting in a result exceeding the equilibrium value. Additionally, it was found that when ultrasonic irradiation and rectified alternating current were combined, the dissolved hydrogen concentration increased transiently.

[Experimental Example 3]

A reduced water production system equipped with a three-chamber electrolyzer shown in FIG. 7 was constructed. For the anode thread, cathode thread, and intermediate thread, the size was set to 6 × 8 × approximately 1 cm. Purified water and 50 g of ascorbic acid were added to the middle chamber (concentration: approximately 5%). This aqueous solution was constantly circulated. Other configurations were the same as in Experimental Example 1.

In this state, full-wave rectification of 50 Hz and 4 A was applied to the cathode electrode, and water was passed at 0.5 L/min. The valve at the outlet of the electrolyzer was adjusted, and the pressure in the cathode chamber was adjusted to 0.1 kg/cm2. The transient dissolved hydrogen molecule concentration measurement value increased by 2.6 ppm compared to 2.3 ppm before the intermediate room liquid circulation.

[Experimental Example 4]

Reduced water was produced in an electrolytic cell using the cathode seal frame (6 × 8 cm2) shown in FIG. 9. The distance between the fluorine-based cation exchange membrane and the porous cathode electrode was set to 1 mm. Raw water treated with tap water using a reverse osmosis membrane filter was supplied to the cathode chamber of the electrolyzer at 0.5 L/min. As shown in Figure 9, five protrusions were installed. When electric current was applied at 50Hz and 4A with full-wave rectification, the dissolved hydrogen concentration was 2.7ppm. By providing the protrusion in this way and increasing the flow rate on the surface of the cathode electrode, it is possible to further increase the dissolved hydrogen concentration.

100: Electrolyzer 1: Anode thread
3: cathode seal 4: cathode electrode
5: Diaphragm 51: Anode actual measurement diaphragm
52: actual cathode diaphragm 6: intermediate chamber
8: Mechanical vibration imparting unit 21: Anode electrode
31: Ion exchange resin 110: Power supply
120: water storage tank 130: water pump
140: Reverse osmosis membrane filter 150: Tap water line
160: Valve 200: Raw material water generation liquid delivery unit
301: Electrolytic surface 302: Raw material water supply line
303: reduced water discharge line 304: manifold for supplying raw water
305: Manifold for discharge of reduced water 306: Raw water inlet
307: reduced water outlet 400: cathode seal frame

Claims (18)

An anode chamber, a cathode chamber, a diaphragm that is a fluorine-based ion exchange membrane disposed between the anode chamber and the cathode chamber, a porous anode electrode disposed in contact with the diaphragm in the anode chamber, and a porous cathode electrode disposed in the cathode chamber. An electrolyzer comprising:
Applying a current having an alternating current component with a current average value of 10 kHz or less to the porous cathode electrode of zero or more to perform electrolytic reduction of water supplied between the diaphragm and the porous cathode electrode to generate hydrogen, and the porous cathode A current having a direct current component is applied to the electrode to perform electrolytic reduction of the water supplied between the diaphragm and the porous cathode electrode to generate hydrogen, and at the same time, an ultrasonic wave in the ultrasonic range of 30 kHz to 10 MHz is applied to the surface of the porous cathode electrode. It includes a concentration reduction suppressor that performs at least one of providing mechanical vibration,
The cathode seal has a plurality of protrusions on a surface opposite to the diaphragm, and the porous cathode electrode is arranged to contact the protrusions at the ends of the protrusions,
The cathode seal has a plurality of supply openings and a plurality of discharge openings in a non-protruding portion of the opposing surface that does not contact the porous cathode electrode,
Water flows into the cathode chamber from the supply opening and is supplied between the porous cathode electrode and the diaphragm through the porous cathode electrode,
Reduced water produced between the porous cathode electrode and the diaphragm flows between the porous cathode electrode and the opposing surface through the porous cathode electrode and is discharged from the discharge opening. According to paragraph 1,
A reduced water production device in which a current having an alternating current component whose current average value of 10 kHz or less is equal to or greater than zero is a current having an alternating current component whose minimum current value is equal to or greater than zero. According to paragraph 1,
A reduced water production device wherein the current having an alternating current component with an average current value of 10 kHz or less equal to or greater than zero is half-wave rectified or full-wave rectified alternating current. According to paragraph 1,
The concentration drop suppressor performs electrolytic reduction of water by applying a half-wave rectified or full-wave rectified alternating current of 10 kHz or less to the porous cathode electrode, and at the same time applies ultrasonic waves of 30 kHz to 10 MHz to the surface of the porous cathode electrode. A reduced water production device that imparts mechanical vibration in the area. According to paragraph 1,
A reduced water production device in which an ion exchange resin is filled between the diaphragm and the porous cathode electrode. According to clause 5,
The concentration drop suppressing section includes an ultrasonic vibrator embedded in the ion exchange resin,
The reduced water production device wherein the concentration drop suppressing section applies mechanical vibration in an ultrasonic range of 30 kHz to 10 MHz from the ultrasonic vibrator to the surface of the porous cathode electrode. According to paragraph 1,
A reduced water production device wherein the distance between the porous cathode electrode and the diaphragm in a direction perpendicular to the diaphragm is 1 mm or less. In clause 7,
A reduced water production device in which the cathode chamber is disposed with the supply opening and the discharge opening interposed between the protrusions. According to any one of claims 1 to 8,
The electrolytic cell is a three-chamber electrolytic cell including the anode chamber, the cathode chamber, and an intermediate chamber disposed between the anode chamber and the cathode chamber and dividing the anode chamber and the cathode chamber by the diaphragm, and in the intermediate chamber A reduced water production device in which a reducing substance is present. An anode chamber, a cathode chamber, a diaphragm that is a fluorine-based ion exchange membrane disposed between the anode chamber and the cathode chamber, a porous anode electrode disposed in contact with the diaphragm in the anode chamber, and a porous cathode electrode disposed in the cathode chamber. Supplying water between the diaphragm and the porous cathode electrode in an electrolytic cell comprising: and
Electrolytic reduction of water is performed by applying a current having an alternating current component whose current average value of 10 kHz or less is zero or more to generate hydrogen to the porous cathode electrode, and applying a current having a direct current component to the porous cathode electrode At least one of performing electrolytic reduction of water to generate hydrogen and applying mechanical vibration in the ultrasonic range of 30 kHz to 10 MHz to the surface of the porous cathode electrode,
The cathode seal has a plurality of protrusions on a surface opposite to the diaphragm, and the porous cathode electrode is arranged to contact the protrusions at the ends of the protrusions,
The cathode seal has a plurality of supply openings and a plurality of discharge openings in a non-protruding portion of the opposing surface that does not contact the porous cathode electrode,
Water flows into the cathode chamber from the supply opening and is supplied between the porous cathode electrode and the diaphragm through the porous cathode electrode,
Generating reduced water between the porous cathode electrode and the diaphragm,
A method for producing reduced water containing hydrogen, wherein reduced water is introduced between the porous cathode electrode and the opposing surface through the porous cathode electrode and discharged from the discharge opening. According to clause 10,
A method for producing reduced water, wherein the current having an alternating current component whose current average value of 10 kHz or less is equal to or greater than zero is a current having an alternating current component whose lowest current value is equal to or greater than zero. According to clause 10,
A method for producing reduced water, wherein the current having an alternating current component with an average current value of 10 kHz or less equal to or greater than zero is half-wave rectified or full-wave rectified alternating current. According to clause 10,
Electrolytic reduction of water is performed by applying a half-wave rectified or full-wave rectified alternating current of 10 kHz or less to the porous cathode electrode, while mechanical vibration in the ultrasonic range of 30 kHz or more and 10 MHz or less is applied to the surface of the porous cathode electrode. Method for producing reduced water. According to clause 10,
A method for producing reduced water, wherein an ion exchange resin is filled between the diaphragm and the porous cathode electrode. According to clause 14,
A method for producing reduced water, wherein mechanical vibration in an ultrasonic range of 30 kHz to 10 MHz is applied to the surface of the porous cathode electrode, and the mechanical vibration is applied from an ultrasonic vibrator embedded in the ion exchange resin. . According to clause 10,
A method for producing reduced water, wherein water is supplied between the porous cathode electrode and the diaphragm in the electrolytic cell where the distance between the porous cathode electrode and the diaphragm in a direction perpendicular to the diaphragm is 1 mm or less. According to clause 16,
A method for producing reduced water, wherein the supply opening and the discharge opening are disposed with the protrusion interposed therebetween. According to any one of claims 10 to 17,
The electrolytic cell is a three-chamber electrolytic cell including the anode chamber, the cathode chamber, and an intermediate chamber disposed between the anode chamber and the cathode chamber and dividing the anode chamber and the cathode chamber by the diaphragm, and in the intermediate chamber A method for producing reduced water in which a reducing substance is present.