JP2016060950A - Electrolytic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an electrolytic device that has high chlorine use efficiency and can prevent the mixture of impurities.SOLUTION: An electrolytic device according to an embodiment comprises: an electrolytic cell comprising an anode chamber, an anion exchange film, an intermediate chamber, a cation exchange film, and a cathode chamber; a first line that extracts chlorine gas provided in the anode chamber; and two or more tanks connected to the first line and brings chlorine gas and aqueous liquid into contact with each other.SELECTED DRAWING: Figure 1

Description

  Embodiments described herein relate generally to an electrolysis apparatus.

  Conventionally, it is widely performed to oxidize chloride ions at an anode in various electrolytic cells to produce chlorine molecules. As an electrolysis apparatus that generates hypochlorous acid water or the like, an electrolysis apparatus having a two-chamber type or a three-chamber type electrolytic cell is used. For example, a three-chamber type electrolytic cell is composed of an anion exchange membrane or a reverse osmosis membrane having a quaternary ammonium salt, a quaternary phosphonium salt or the like, and a cation exchange membrane such as Nafion, so that the electrolytic cell is an anode chamber, an intermediate chamber and a cathode chamber. And divided into three rooms. An anode and a cathode are respectively disposed in the anode chamber and the cathode chamber.

  In such a three-chamber electrolyzer, for example, a saline solution is passed through the intermediate chamber, water is passed through the left and right cathode chambers and the anode chamber, and the saline solution in the intermediate chamber is electrolyzed with the cathode and the anode. Hypochlorous acid water is generated from chlorine gas generated in the chamber, and sodium hydroxide water is generated in the cathode chamber. The produced hypochlorous acid water is used as sterilizing / disinfecting water, and sodium hydroxide water is used as washing water.

  The two-chamber type electrolytic cell is composed of a cation exchange membrane such as Nafion, an anion exchange membrane having a quaternary ammonium salt or a quaternary phosphonium salt, or a reverse osmosis membrane. Separated into rooms. An anode and a cathode are respectively disposed in the anode chamber and the cathode chamber.

  In such a two-chamber electrolyzer, for example, salt solution is flowed into the anode chamber, water is flowed into the cathode chamber, and the salt solution is electrolyzed at the anode, so that hypochlorine is generated from chlorine gas generated in the anode chamber. Acid water is generated.

A specific reaction of hypochlorous acid aqueous solution is shown below. When chlorine gas generated by electrolysis dissolves in water, hydrochloric acid and hypochlorous acid are generated according to the following equilibrium reaction equation (1).

  Hypochlorous acid water can be produced by mixing chlorine gas and water, but as shown in the formula (1), hydrochloric acid is generated simultaneously with hypochlorous acid. Therefore, the pH of hypochlorous acid water will fluctuate.

  FIG. 2 is a graph showing the relationship between pH and the effective hypochlorite residual rate of chlorine.

  200 is a graph showing the relationship between pH and residual hypochlorous acid residual ratio of chlorine, region 201 is strongly acidic electrolyzed water, region 202 is weakly acidic electrolyzed water, region 203 is slightly acidic electrolyzed water, and region 204 is hypoxia. Sodium chlorate, region 205, each represents chlorine.

  When hypochlorous acid is produced by bringing chlorine into contact with water, hydrochloric acid is produced at the same time. As hydrochloric acid increases, the pH gradually decreases. At this time, as shown in FIG. 2, in the region where the pH is 5 or less, the proportion of chlorine increases and the proportion of hypochlorous acid decreases as the pH decreases. That is, there is a problem that the ratio of hypochlorous acid that can be generated from a certain amount of chlorine is relatively decreased as the pH is lowered.

  Moreover, when generation | occurrence | production of chlorine gas as mentioned above will cause a strange odor, it is necessary to attach a processing machine separately also in processing.

  Furthermore, when flowing into the anode chamber, there is a problem that impurities and salts eluted from the electrodes and membranes are mixed with hypochlorous acid water. If impurities are mixed in hypochlorous acid water, it cannot be used for foods, and if salt is mixed in hypochlorous acid water, corrosion of piping may be accelerated.

JP 2012-255200 A

  An object of the present invention is to obtain an electrolysis apparatus that has high use efficiency of chlorine and is capable of suppressing mixing of impurities.

According to the embodiment, an electrolytic cell including an anode chamber having an anode, an intermediate chamber partitioned by the anode chamber from a first diaphragm, and a cathode chamber having a cathode partitioned by the intermediate chamber and a second diaphragm When,
A first line for extracting chlorine gas from the anode chamber;
An electrolysis apparatus is provided, comprising two or more tanks connected to the first line and in contact with chlorine gas and water.

1 is a schematic cross-sectional view of an electrolysis apparatus according to a first embodiment. It is a graph showing the relationship between pH and the effective hypochlorous residual rate of chlorine. It is a schematic sectional drawing of the electrolysis apparatus concerning a 2nd embodiment. It is the schematic showing the modification of the electrolyzer concerning 1st Embodiment. It is the schematic showing an example of the comparative electrolysis apparatus. It is the schematic showing other examples of a comparative electrolysis device.

  An electrolysis apparatus according to a first embodiment includes an anode chamber having an anode, an intermediate chamber partitioned by an anode chamber and a first diaphragm, and a cathode chamber having a cathode partitioned by the intermediate chamber and a second diaphragm. It has an electrolytic cell containing.

  The intermediate chamber can be provided with a first supply mechanism for supplying an aqueous electrolyte solution containing inorganic chloride. The second supply mechanism for supplying the aqueous liquid can be provided in the cathode chamber, but is not provided in the anode chamber. A first line for taking out chlorine gas is provided in the anode chamber. Further, two or more tanks are provided downstream of the anode chamber and connected to the first line for bringing the extracted chlorine gas into contact with the aqueous liquid to create hypochlorous acid water. . The cathode chamber can optionally be provided with a line for extracting alkaline water.

  The electrolysis apparatus according to the second embodiment has an electrolytic cell including an anode chamber having an anode, and a cathode chamber having a cathode, which is partitioned by an anode chamber and a first diaphragm.

  The cathode chamber can be provided with a first supply mechanism for supplying an aqueous electrolyte solution containing inorganic chloride. A first line for taking out chlorine gas is provided in the anode chamber. Further, two or more tanks are provided downstream of the anode chamber and connected to the first line to make the extracted chlorine gas contact with water to produce hypochlorous acid water. The cathode chamber can optionally be provided with a line for extracting alkaline water.

  In the electrolysis apparatus according to the embodiment, without supplying water to the anode chamber, chlorine gas generated at the anode is sent to two or more tanks provided at the rear stage of the anode chamber, where the chlorine gas is turned into an aqueous liquid. By bringing it into contact, hypochlorous acid water can be generated. Since the chlorine gas taken out from the anode chamber is taken out from the anode chamber in a gas state, impurities derived from the catalyst, the anion exchange membrane, and the salt water used in the anode chamber are not easily mixed into the hypochlorous acid water.

  In addition, as an aqueous liquid, water, hypochlorous acid water, etc. can be used, for example.

  Various embodiments will be described below with reference to the drawings. In addition, the same code | symbol shall be attached | subjected to a common structure through embodiment, and the overlapping description is abbreviate | omitted. In addition, each drawing is a schematic diagram for promoting the embodiment and its understanding, and its shape, dimensions, ratio, etc. are different from the actual device, but these are considered in consideration of the following description and known techniques. The design can be changed as appropriate.

(First embodiment)
FIG. 1 is a schematic cross-sectional view of an electrolysis apparatus having a three-chamber electrolytic cell according to the first embodiment.

  As shown in FIG. 1, the electrolyzer 10 can be roughly divided into a three-chamber type electrolytic cell 11 and a hypochlorous acid production unit 12. The three-chamber electrolytic cell 11 is partitioned by an anion exchange membrane 21, partitioned by an anode chamber 4 having an anode 1 and a cation exchange membrane 23, a cathode chamber 5 having a cathode 3, and the anode chamber 4. It consists of an intermediate chamber 2 sandwiched between a cathode chamber 5 and partitioned by an anion exchange membrane 21 and a cation exchange membrane 23. The anode chamber 4 is not filled with liquid, and in the initial state, for example, air is contained. Water is supplied to the cathode chamber 5 from the water supply line 101 using a pump or the like. The intermediate chamber 2 is supplied with salt water from the salt water supply line 102 using a pump or the like.

  A power source 13 is connected between the electrodes 1 and 3 of the anode chamber 4 and the cathode chamber 5. By applying a voltage from the power source 13, hydroxyl ions are generated in the cathode chamber 5 by electrolysis of water, and positive ions are generated. By reacting with sodium ions that have passed through the ion membrane, sodium hydroxide is produced.

  On the other hand, in the anode chamber 4, chloride ions that have passed through the anion exchange membrane 21 from the intermediate chamber 2 are oxidized to generate chlorine gas. The chlorine gas generated at this time is taken out from a chlorine gas line 110 provided in the upper part of the anode chamber 4 and is poured into the subsequent hypochlorous acid production unit 12 to generate hypochlorous acid water.

  The hypochlorous acid production unit 12 includes a front tank 6, a front discharge cock 7, a hypochlorous acid water line 104, a rear tank 8 connected in series with the front tank 6, a rear liquid discharge cock 9, and hypochlorous acid water. It consists of line 105. The tanks 6 and 8 and the liquid discharge cock may be connected in two or more stages, or may be connected in parallel. However, when tanks 6 and 8 are connected in parallel, the pH of each hypochlorous acid water in tanks 6 and 8 can be changed by changing the amount of chlorine gas dissolved, such as changing the amount of water in the tank. You can turn it on. Even when connected in series, the desired pH of each hypochlorous acid water can be obtained by changing the amount of water in the tanks 6 and 8. In addition, although two tanks 6 and 8 are used here, the number of tanks can be increased to three or more in order to increase efficiency according to the electrolytic current and the liquid capacity of the tank. In addition, in the tanks 6 and 8, for example, a chlorine gas line 110 and a chlorine gas line 111 for sending the chlorine gas taken out from the tank 6 to the subsequent tank 8 are inserted below the water surface of the tanks 6 and 8, respectively. Thus, a mechanism for bubbling chlorine gas into the water is provided.

  According to the embodiment, by connecting the tanks in this manner, the tank in the vicinity of the electrolytic cell has a low pH, and the tank far from the electrolytic cell can have a higher pH. And the utilization efficiency of chlorine can be improved by collect | recovering the chlorine gas discharged | emitted by the tank with low pH by a tank of a back | latter stage. At this time, the pH of the preceding tank is preferably between 2 and 3, and the pH of the latter tank is preferably between 3 and 6.5. Hypochlorous acid water produced by changing the pH in this way, for example, strong acid hypochlorous acid water having a pH of 2 to 3 in the previous stage has a chlorine odor when used, but in a sealed space because of its strong bactericidal action. If used, various viruses can be killed in a very short time. Therefore, it can be sterilized by directly immersing food, or it can be sterilized by attaching it to shoes, gloves, trays or car tires to prevent Norovirus diffusion. In addition, low acidity hypochlorous acid water with a low environmental load of 3.0 to 6.5 is less likely to generate chlorine gas, so there is no odor of chlorine. It can be sprayed for use, or it can be used for hand washing and disinfection that directly touches the human body or for purification of the body such as gargle.

The diaphragm used in the electrolytic cell 11 is a polymer electrolyte membrane, for example, a cation exchange membrane or an anion exchange membrane. Specifically, the second membrane is a cation exchange membrane, and the first membrane is an anion. A hydrocarbon-based membrane can be used as the ion exchange membrane or the second diaphragm. As cation exchange membranes, NAFION (EI DuPont: Trademark) 112, 115, 117, Flemion (Asahi Glass Co., Ltd .: Trademark), ACIPLEX (Asahi Kasei Co., Ltd .: Trademark), Gore Select (W.L. Gore and Associates) Company: Trademark). Examples of the anion exchange membrane include A201 manufactured by Tokuyama Corporation.

  As an electrode, a catalyst layer can be formed on the surface of a base material using a valve metal such as titanium, chromium, aluminum or an alloy thereof as a base material. When used for the anode, a noble metal catalyst such as platinum or an oxide catalyst such as iridium oxide or ruthenium oxide can be used.

  In addition, in a general two-chamber electrolytic cell that does not generate chlorine, salt water is sent directly to the anode, and thus impurities such as ruthenium oxide and salt water that have dissolved from the electrode are included. Salt water changes the taste of food, and when sprayed, it can corrode metals. Also, mixing ruthenium oxide or iridium into food is considered inappropriate.

Similarly, even in a three-chamber type electrolytic cell, since liquid is directly fed to the anode, impurities such as ruthenium oxide dissolved from the electrode are included, which is inappropriate.

  On the other hand, in the electrolysis apparatus according to the embodiment, chlorine gas generated in the anode chamber is taken out from the anode chamber in a gas state, so that it is difficult to carry salt components and impurities dissolved from the electrode to the subsequent tank. There are advantages. Although water diffusing from the intermediate chamber may accumulate in the anode chamber, the generated chlorine gas and the accumulated water in the anode chamber can be easily separated by gravity. The separated accumulated water can be discharged from the anode chamber by providing a drain line as necessary. Therefore, as shown in FIG. 1, the piping for taking out chlorine gas can be installed on the upper side in the gravity direction of the anode chamber 4.

(Second Embodiment)
FIG. 3 shows a schematic diagram of an electrolysis apparatus having a two-chamber electrolytic cell according to the second embodiment.

  The electrolyzer 10 ′ has the same configuration as that shown in FIG. 1 except that a two-chamber electrolyzer 11 ′ is used instead of the three-chamber electrolyzer 11.

  In the first embodiment, the three-chamber electrolytic cell is mainly described. However, in the case of the two-chamber electrolytic cell 11 ′ according to the second embodiment, a quaternary ammonium salt or a quaternary phosphonium is used. The electrolytic cell 11 ′ is divided into two chambers, an anode chamber 4 ′ and a cathode chamber 5 ′, by an anion exchange membrane or a reverse osmosis membrane 24 having a salt or the like. In such a two-chamber electrolytic cell 11 ′, saline is passed through the cathode chamber 5 ′ and no liquid is passed through the anode chamber 4 ′. At this time, the movement of chlorine is not limited to the diffusion from the cathode 3 ′, but pressure can be applied to the cathode chamber 5 ′ to promote the movement of chlorine ions to the anode 1 ′, or a high voltage can be applied to the anode 1 ′. The movement of chlorine ions can be promoted by the electric field gradient. By electrolyzing the chlorine ions that have passed through the membrane 24 from the cathode 3 ′ at the anode 1 ′, hypochlorous acid water can be generated by generating chlorine gas in the anode chamber 4 ′ and sending it to a connected tank.

Modified Example of First Embodiment FIG. 4 is a schematic diagram showing a modified example of the electrolysis apparatus according to the first embodiment.

  The electrolysis apparatus 20 according to the second embodiment has the same configuration as that of FIG. 1 except that the lower stage of the anode chamber 4 of the electrolytic cell 11 is further equipped with a liquid discharge cock 14 and a drain line 106. . The water accumulated by moving from the intermediate chamber 2 to the anode chamber 4 can be discharged by the cock 14 and the drain line 106. The generated chlorine gas and this water can be easily separated by gravity.

Comparative Electrolyzer Configuration Example 1
FIG. 5 shows a schematic diagram illustrating an example of a comparative electrolysis apparatus.

  As shown in the drawing, the comparative electrolyzer 30 has the same configuration as that of FIG. 1 except that the rear tank 8 is not provided. Only the front tank 6 is provided downstream of the anode chamber 4.

Comparative electrolytic device configuration example 2
FIG. 6 shows a schematic diagram illustrating another example of the comparative electrolysis apparatus.

  The comparative electrolyzer 40 is further provided with a water supply line 107 for supplying water to the anode chamber 4 using a pump or the like, and a hypochlorous acid water line is provided in the rear stage of the anode chamber 4 in place of the hypochlorous acid production unit 12. 108 and a hypochlorous acid tank 18 are provided, and the hypochlorous acid water generated in the anode chamber is taken out from the hypochlorous acid water line 108 and accommodated in the hypochlorous acid tank 18. It has a configuration. As shown in the figure, water is supplied directly, and the generated chlorine is converted to hypochlorous acid in the anode chamber, so the hypochlorous acid water is recovered in the tank in the subsequent stage. In this electrolyzer 40, since liquid water is directly supplied to the anode chamber 4, impurities eluted from the anode and salt water diffusing from the intermediate chamber may be mixed with hypochlorous acid water.

Example 1
The electrode base materials of the anode and the cathode are made of 0.5 mm flat titanium, and W of the linear portion is 1.0 mm and LW is 2.0 mm. The angle θ of the opening opened in the rhombus is 120 °.

A solution prepared by adding 1-butanol to iridium chloride (IrCl ₃ .nH ₂ O) to 0.25 M (Ir) was previously treated at 80 ° C. for 1 hour in a 10 wt% oxalic acid aqueous solution. . The solution thus prepared is applied to the electrode substrate, and then dried and fired. In this case, drying is performed at 80 ° C. for 10 minutes, and baking is performed at 450 ° C. for 10 minutes. An electrode base material obtained by repeating such coating, drying, and firing 5 times is cut out into a reaction electrode area of 10 cm × 20 cm, and this is used as an anode.

  Next, a cathode is formed by sputtering platinum on the electrode substrate.

  The electrolyzer 10 shown in FIG. 1 is produced using these electrodes.

  As the diaphragm for the anode 1, A201 made by Tokuyama, which is an anion exchange membrane, is used, and Nafion 117 is used as the diaphragm for the cathode 3.

  A container for supplying saturated saline to porous polystyrene is used for the anode chamber 4, the cathode chamber 5, and the intermediate chamber 2 made of vinyl chloride in which straight channels are formed, and these are superposed to constitute an electrolytic cell.

  A power source 13 is installed, a pipe and a pump for supplying tap water to the cathode chamber 5, and a saturated saline reservoir, a pipe and a pump for circulating and supplying saturated saline to the porous polystyrene are installed in the intermediate chamber 2. .

  Using this electrolyzer 10, electrolysis is performed for 1 hour at a voltage of 5 V, and chlorine gas is produced on the anode side and sodium hydroxide water is produced on the cathode side.

  At this time, 10 liters of water was put into each of the front tank 6 and the rear tank 8, and the gas pipe inlet was installed at a depth of 5 cm from the water surface.

  After 1 hour of electrolysis, the pH of the front tank was 2.5, and the pH of the rear tank was 5.

The effective chlorine utilization rate at this time was 95% or more. Further, the amount of iridium metal contained in the former tank and the latter tank was 1 μg / liter or less even when measured by ICP. Similarly, the salt was 10 mg / liter or less.

(Comparative Example 1)
The electrolytic device 30 described in the configuration example 1 of the comparative electrolytic device was produced, and hypochlorous acid was produced.

  At this time, 20 liters of water was put into the tank, and an inlet of the gas pipe was installed at a depth of 10 cm from the water surface. The pH of the tank was 3.5 after 1 hour of electrolysis.

  The effective chlorine utilization rate at this time was 60%.

  Thereby, it turns out that chlorine effective efficiency improves by connecting two or more rather than one tank.

(Comparative Example 2)
The electrolysis apparatus described in the fourth embodiment was produced, and hypochlorous acid was produced. At this time, water was fed into the anode chamber at a rate of 20 liters / hour. The pH of the hypochlorous acid recovery tank was 3.5 after 1 hour of electrolysis.

  The effective chlorine utilization rate at this time was 60%. The amount of iridium metal contained in the front tank and the rear tank was 10 μg / liter. Similarly, the salt was 80 mg / liter.

  When liquid water is sent directly to the anode chamber, it can be seen that impurities eluted from the anode and salt water diffusing from the intermediate chamber are mixed into the hypochlorous acid water.

(Example 2)
An electrolytic cell having the same electrolytic cell as in Example 1 and a hypochlorous acid production unit, and further, discharging the water moving from the intermediate chamber 2 to the anode 1 by the cock 14 as shown in the second embodiment is produced. . Using this electrolyzer, electrolysis is performed at a voltage of 5 V, chlorine gas is produced on the anode side, and sodium hydroxide water is produced on the cathode side.

  By discharging the water accumulated in the anode chamber from the cock 14 every 24 hours, hypochlorous acid can be produced even in operation for 2000 hours. At this time, the iridium metal contained in the preceding tank and the latter tank The amount was 1 μg / liter or less as measured by ICP. Similarly, the salt was 10 mg / liter or less.

(Example 3)
In the system of Example 1 in which the moisture cock 14 was not used, 80% of the anode chamber was filled with permeated water from the intermediate chamber after 100 hours of operation. The amount of iridium metal contained in the former tank and the latter tank after 2000 hours of operation was 10 μg / liter. The salt was 90 mg / liter.

  It is thought that the water that permeated into the anode chamber, the salt, and the water containing the catalyst dissolved from the anode passed through the anode rear piping in a two-layer flow with chlorine gas and flowed into the hypochlorous acid production tank in the subsequent stage. It is done. For this reason, when the liquid was periodically discharged from the anode chamber, the amount of iridium metal in the former tank and the latter tank was 1 μg / liter or less even when measured by ICP. Similarly, the salt was 10 mg / liter or less.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 1 ... Anode, 4 ... Anode chamber, 21 and 23 ... Diaphragm, 2 ... Intermediate chamber, 3 ... Cathode, 11, 15 ... Electrolyzer, 102 ... Electrolyte aqueous solution supply mechanism, 101 ... Water supply mechanism, 103 ... Line, 110 ... First 1 line, 6, 8 ... tank, 10, 20 ... electrolyzer

Claims (8)

An electrolytic cell including an anode chamber having an anode, an intermediate chamber partitioned from the anode chamber by a first diaphragm, and a cathode chamber having a cathode, partitioned by the intermediate chamber and a second diaphragm;
A first line for extracting chlorine gas from the anode chamber;
An electrolysis apparatus comprising two or more tanks connected to the first line and contacting chlorine gas and an aqueous liquid. An electrolytic cell including an anode chamber having an anode, a cathode chamber having a cathode partitioned from the anode chamber by a first diaphragm;
A first line for extracting chlorine gas from the anode chamber;
An electrolysis apparatus comprising two or more tanks connected to the first line and contacting chlorine gas and an aqueous liquid. The two or more tanks are
A first tank connected to the first line for producing a first hypochlorous acid water by contacting chlorine gas with an aqueous liquid;
A second line for removing excess chlorine gas from the first tank;
The second tank connected to the second line and configured to make a second hypochlorous acid water by bringing chlorine gas and an aqueous liquid into contact with each other. Electrolytic device.   The electrolysis apparatus according to claim 3, wherein the pH of the first hypochlorous acid water is different from the pH of the second hypochlorous acid water.   5. The electrolyzer according to claim 4, wherein the pH of the second hypochlorous acid water is higher than the pH of the first hypochlorous acid water. 6.   The electrolyzer according to any one of claims 1 to 5, wherein the product from the anode chamber is gas-liquid separated by gravity.   The electrolysis apparatus according to claim 1, further comprising a drainage mechanism in the anode chamber.   The electrolysis apparatus according to any one of claims 1 to 7, wherein chlorine gas is bubbled into an aqueous liquid in the two or more tanks.

Images