JP2005138001A - Manufacturing method of aqueous hypochlorous acid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an manufacturing apparatus of aqueous hypochlorous acid capable of easily adjusting pH after dilution to a slight acidic region, and a manufacturing method of aqueous hypochlorous acid. <P>SOLUTION: This manufacturing apparatus 1 of aqueous hypochlorous acid is equipped with a main electrolytic cell 5 for electrolyzing hydrochloric acid-added raw water, an intermediate dilution means 6 for diluting a primarily electrolytically treated liquid being the electrolytically treated liquid discharged from the main electrolytic cell 5 and a sub-electrolytic cell 7 for electrolyzing an intermediate diluted liquid diluted by the intermediate dilution means 6. After the hydrochloric acid-added raw water is electrolytically treated (primary electrolytic treatment process), the obtained electrolytically treated liquid (primary electrolytically treated liquid) is diluted with raw water (intermediate dilutionj process) and electrolytic treatment is again performed after dilution (secondary electrolytic treatment process). Since a chlorine simple substance remaining in the primary electrolytically treated liquid is reacted with water to produce hydrochloric acid which is, in turn, electrolytically treated, the remaining chlorine simple substance is extremely reduced and aqueous hypochlorous acid easily adjustable to a slight acidic region can be manufactured. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an apparatus and a method for producing hypochlorous acid water for producing hypochlorous acid water that is water containing hypochlorous acid (HOCl). More specifically, the apparatus and method for producing hypochlorous acid water suitable for the preparation of slightly acidic hypochlorous acid water with a small ratio of chlorine alone or hydrochloric acid to chlorine (as an element) contained in the hypochlorous acid water About.

In recent years, a technique for generating hypochlorous acid water by electrolytic treatment of hydrochloric acid-added water obtained by adding hydrochloric acid to raw water in an electrolytic cell has been developed (see, for example, Patent Documents 1 and 2).
In this technology, as shown in the following chemical reaction formula, chloride ions generated by the ionization of hydrochloric acid (formula 1) are oxidized to produce simple chlorine (formula 2), and the simple chlorine reacts with water to produce hypochlorous acid. (Equation 3). In these reactions, hydrochloric acid produced as a by-product of the reaction between simple chlorine and water is electrolyzed again, so that theoretically, all hydrochloric acid can be converted to hypochlorous acid.

HCl → H ⁺ + Cl ⁻ (1)
2Cl ⁻ → Cl ₂ + 2e ⁻ (2)
Cl ₂ + H ₂ O → HOCl + HCl (3)

Hypochlorous acid water obtained by this technique can be diluted with water to an appropriate concentration and used as a disinfectant. The electrolytic treatment solution has a high bactericidal effect even at a low chlorine concentration, for example, compared to an aqueous solution of hypochlorite such as sodium hypochlorite, and a fine concentration adjustment every time it is used. Therefore, it is suitable as a bactericidal agent.
JP-A-10-128336 JP 2000-5757 A

  The hypochlorous acid water produced by the above-described conventional production method has an extremely low pH before dilution of 1 or less and a very high chlorine concentration of around 10,000 ppm. Therefore, the reaction of the above formula (3) occurs during the electrolytic treatment. It does not travel rightward enough, leaving a significant amount of chlorine alone. The residual chlorine alone undergoes the reaction of the formula (3) after dilution, and hydrochloric acid is generated. When normal raw water such as tap water, groundwater, underground water, etc. is used, hardness components such as Ca and Mg are included, so the neutralized buffering capacity of the hardness components makes the pH after dilution slightly acidic. It is easy to adjust to (pH 5 to 6.5).

However, when raw water, such as ultra-soft water, RO water (water purified by reverse osmosis membrane), or distilled water, is used, the pH after dilution is too low and slightly acidic. There was a problem that it may not be adjusted to the area. In this case, if it dilutes until pH becomes a slightly acidic range, the density | concentration of hypochlorous acid will fall to such an extent that sufficient disinfection power is hard to be acquired.
Patent Document 2 also describes a method of adjusting the pH of diluted hypochlorous acid water using an alkaline alkali metal salt such as sodium hydroxide as a neutralizing agent. However, when the pH of hypochlorous acid water is adjusted using a neutralizing agent, it is conceivable that the place where it can be used and the method may be restricted due to the salt content (salts such as sodium chloride) generated by neutralization. It is done.

  The present invention has been made in view of the above circumstances, and an apparatus and method for producing hypochlorous acid water capable of easily adjusting the pH after diluting hypochlorous acid water for use to a slightly acidic range It is an issue to provide.

In order to solve the above problems, the present invention comprises a main electrolytic tank for electrolytically treating hydrochloric acid-added raw water, and intermediate diluting means for diluting a primary electrolytic treated liquid that is an electrolytic treated liquid discharged from the main electrolytic tank with raw water, An apparatus for producing hypochlorous acid water is provided, comprising: a sub-electrolysis tank that electrolyzes the intermediate diluted solution diluted by the intermediate dilution means.
The apparatus for producing hypochlorous acid water according to the present invention may further comprise a final diluting means for diluting a secondary electrolytic treatment liquid, which is an electrolytic treatment liquid discharged from the sub-electrolysis tank, with raw water.
The present invention also includes a primary electrolytic treatment step of electrolytically treating hydrochloric acid-added raw water, an intermediate dilution step of diluting a primary electrolytic treatment solution obtained by the primary electrolytic treatment step with raw water, and the intermediate dilution There is provided a method for producing hypochlorous acid water, comprising a secondary electrolytic treatment step of subjecting an intermediate dilution obtained by the step to electrolytic treatment.
The method for producing hypochlorous acid water of the present invention may further include a final dilution step of diluting a secondary electrolytic treatment solution, which is an electrolytic treatment solution obtained by the secondary electrolytic treatment step, with raw water.
The effective chlorine concentration of the intermediate diluted electrolytic treatment liquid is preferably 1000 ppm or less.

  According to the present invention, by intermediate dilution, chlorine alone in the primary electrolytic treatment solution is reacted with water to produce hypochlorous acid and hydrochloric acid, and the resulting hydrochloric acid is subjected to electrolytic treatment again, thereby reducing hypochlorous acid. Can be oxidized. That is, it is possible to effectively reduce the ratio of hydrochloric acid to hypochlorous acid in the hypochlorous acid water to be finally produced, thereby obtaining hypochlorous acid water having a higher pH. Even if the obtained hypochlorous acid water uses ultra-soft water, RO water, distilled water or the like having a low content of hardness components such as Ca and Mg as raw water, the pH after dilution is slightly acidic ( It can be reliably adjusted to pH 5 to 6.5). Since it can be diluted to a slightly acidic range without using a neutralizer, the slightly acidic hypochlorous acid water after dilution has a very low salt content, and the degree of freedom in the place where it can be used and the method of use Will spread and become highly usable.

The present invention will be described below based on the best mode.
In the present invention, hydrochloric acid-added raw water is defined as hydrochloric acid-added water or an aqueous solution in which a chemical substance is dissolved, and hydrochloric acid is added, but in order to maximize the effects of the present invention, it is relatively high. It is desirable to use hydrochloric acid-added raw water obtained by adding hydrochloric acid having a concentration to water. In other words, it is desirable to use hydrochloric acid-added raw water containing only hydrogen chloride.
The concentration of hydrochloric acid (hydrogen chloride) in the raw water added with hydrochloric acid is 0.01% (mass% or less, the same unless otherwise specified) in order to cause an appropriate reaction in the primary electrolysis means (main electrolytic cell). It is desirable that it is 0.1% or more. However, when pursuing economy, the hydrogen chloride concentration is desirably 1.0% or more and 21.0% or less. That is, if the hydrogen chloride concentration is 1.0% or more, an industrially stable reaction can be obtained, and if it is 21.0% or less, no smoke is generated at room temperature, and storage and handling are possible. This is desirable.

The raw water used in the present invention is tap water, groundwater, underground water, desalted water, distilled water, purified water (RO water, membrane treated water), mixed water thereof, and the like, and substantially does not contain sodium chloride. It is water. Here, “substantially no sodium chloride” means that there is no artificial addition of sodium to the raw water and the sodium ion concentration is 200 ppm or less.
The present invention can be applied to raw water containing hardness components such as Ca ions and Mg ions, such as tap water, ground water, underground water, etc. (hardness is 10 or more). (Water purified by reverse osmosis membrane), like distilled water, when water with very low hardness component content (hardness less than 10) is used as raw water, to slightly acidic range (pH 5 to 6.5) Is easy to adjust and is particularly suitable.

The hydrochloric acid-added raw water is subjected to electrolytic treatment in the first electrolysis means (main electrolytic cell).
In general, when an electrode is composed of a plurality of electrode plates and is energized in an electrolytic cell, conventionally, two types of methods, known as a monopolar type and a multipolar type, are known (Electrochemical Co., Ltd.). Association, "Electrochemical Handbook", page 510, Maruzen, 1959). The monopolar type is a type in which all of the electrode plates are either a cathode or an anode, and the bipolar type has, for example, a structure in which a plurality of electrodes are insulated from each other at a constant interval and stacked. Between the electrode plate connected to the anode of the power source and the electrode plate connected to the cathode of the power source, there is at least one electrode (hereinafter referred to as an intermediate electrode) that is not connected to any electrode. (In this specification, an electrode for performing a monopolar energization method is referred to as a monopolar electrode, and an electrode for performing a bipolar energization method is referred to as a bipolar electrode). As described in Patent Document 2, a bipolar electrode has various advantages over a monopolar electrode. As described in Patent Document 2, a diaphragm electrode is used as an electrolytic cell, and a bipolar electrode is used as an electrode for electrolysis. By adopting the type electrode, various effects such as improvement of electrolysis efficiency, reduction of running cost, and extension of electrode life can be obtained.

In the first electrolysis means (main electrolytic cell), most of the chlorine (90% or more) present as chlorine ions in the hydrochloric acid-added raw water is electrolytically oxidized. For example, if the hydrochloric acid concentration of the hydrochloric acid-added raw water is 1.0%, the primary electrolytic treatment solution obtained by electrolytic treatment of the hydrochloric acid-added raw water in the main electrolytic cell 5 has an extremely low pH of around 1 and an effective chlorine concentration. Becomes a very high liquid of around 100,000 ppm.
When the concentration of chlorine alone in the electrolytic treatment solution becomes so high, the reaction between chlorine alone and water (formula 3 above) does not proceed sufficiently to the right, and hydrochloric acid (Cl oxidation number is -I). However, the rate of oxidation to hypochlorous acid (the oxidation number of Cl is + I) decreases, and chlorine alone (the oxidation number of Cl is 0) remains.
As a result of intensive studies by the present inventors, in the conventional production method, the pH may be lower than the slightly acidic range when the electrolytic treatment solution is diluted. It was found that hydrochloric acid was produced by the reaction between the chlorine alone remaining in the water and water.

  Therefore, the present inventor conducted an electrolytic treatment (first electrolysis step) of the hydrochloric acid-added raw water, and then diluted the primary electrolytic treatment solution with the raw water (intermediate dilution step) to remove the chlorine alone remaining in the primary electrolytic treatment solution. And hypochlorous acid disproportionate, and the resulting hydrochloric acid is again subjected to electrolytic treatment (second electrolysis step), so that the residual chlorine alone is extremely small, and the pH when diluted (final dilution step) It was found that hypochlorous acid water that can be easily adjusted to a slightly acidic region can be produced, and the present invention was completed.

In the intermediate dilution step, an intermediate diluted solution that is a solution obtained by diluting the primary electrolytic treatment solution with raw water is prepared. The intermediate diluted solution may be diluted so that the pH is 2 or more and the effective chlorine concentration is 1000 ppm or less.
In the second electrolysis means (sub-electrolyzer), it is preferable to continue energization until the pH becomes 3 or more. As a result, hydrochloric acid and chlorine remaining in the intermediate diluted solution are oxidized to hypochlorous acid at a very high rate, and the pH of the electrolytic treatment solution becomes high. When finally diluted, the pH of hypochlorous acid water is increased. Can be easily adjusted to a slightly acidic range.

In the production method of the present invention, the secondary electrolytic treatment liquid that is the electrolytic treatment liquid discharged from the second electrolysis means has a low ratio of hydrochloric acid and chlorine alone, and a hypochlorous acid with a very high ratio of hypochlorous acid. It becomes acid water. When the pH is lower than the slightly acidic region, this hypochlorous acid water can be used by diluting with raw water so that it finally becomes the slightly acidic region. Further, as a subsequent step of the second electrolysis step, a final dilution step may be further provided, and the secondary electrolysis solution may be collected after being diluted with raw water.
In the final dilution step, dilution is preferable in terms of sterilization effect if the effective chlorine concentration of the electrolytic treatment solution after dilution is within a range of 0.1 ppm or more. In general, the effective chlorine concentration of hypochlorous acid water depends on the energization conditions, but in any case, when used as a disinfectant, the effective chlorine concentration of hypochlorous acid water is 0.1 ppm or more. A range of the value of is desirable. Further, when paying attention to pH, the pH of hypochlorous acid water after the final dilution is preferably 7.5 or less, more preferably in the range of pH 3.5 or more and 7.0 or less, and particularly preferably pH Is in the range of 5 or more and 6.5 or less. That is, if the pH of the diluted hypochlorous acid water is in such a range, free hypochlorous acid can be present relatively stably in the liquid.
Moreover, if the effective chlorine concentration of the hypochlorous acid water after the final dilution is in the range of 0.1 ppm or more, it is preferable in terms of effects such as sterilization. A particularly preferable range of effective chlorine concentration is 10 to 30 ppm. The effective chlorine concentration can be measured by the iodine titration method prescribed in JIS K 0101.

  According to the method for producing hypochlorous acid water of the present invention, by intermediate dilution, chlorine alone in the primary electrolytic treatment liquid is reacted with water to produce hypochlorous acid and hydrochloric acid, and the resulting hydrochloric acid is again subjected to electrolytic treatment. By doing so, it can oxidize to hypochlorous acid. That is, the ratio of hydrochloric acid and chlorine alone in hypochlorous acid water to be finally produced is effectively reduced, the ratio of chlorine present as hypochlorous acid is increased, and hypochlorous acid having a relatively low acidity. Acid water can be obtained. The obtained hypochlorous acid water is diluted to an appropriate concentration with raw water even when ultra-soft water, RO water, distilled water or the like having a low content of hardness components such as Ca and Mg is used as raw water. The pH can be adjusted to a slightly acidic range (pH 5 to 6.5). Since a neutralizing agent is not required for adjusting the pH of hypochlorous acid water, it takes no effort to adjust the pH, and no alkali is used, so safety can be improved. The slightly acidic hypochlorous acid water produced by the present invention does not contain salt derived from the neutralizing agent, and can be said to be substantially free of salt derived from raw water. Inconveniences such as generation of rust can be suppressed. Therefore, the place where the hypochlorous acid water can be used and the degree of freedom of the use method are widened, and the utility is excellent.

Hereinafter, an apparatus for producing hypochlorous acid water of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram showing an embodiment of a hypochlorous acid water production apparatus according to the present invention.
The hypochlorous acid water production apparatus 1 shown in FIG. 1 has a main pipe 2 through which raw water flows and a part of the raw water that flows from the first branch point 2a of the main pipe 2 and flows through the main pipe 2 through main electrolysis. A primary branch pipe 3 to be supplied to the tank 5, a hydrochloric acid supply means 4 for supplying hydrochloric acid to the primary branch pipe 3, a main electrolytic tank 5 for electrolytically treating hydrochloric acid-added raw water supplied from the primary branch pipe 3, and the main A part of the raw water branched from the second branch point 2 b set downstream of the first branch point 2 a of the pipe 2 and flowing through the main pipe 2 is supplied to the sub-electrolysis tank 7 and discharged from the main electrolytic tank 5. The secondary branch pipe 6 for diluting the primary electrolytic treatment liquid that is the electrolytic treatment liquid thus prepared, and the sub-electrolysis tank 7 for electrolytically treating the diluted electrolytic treatment liquid that is a solution obtained by diluting the primary electrolytic treatment liquid with raw water.

  The main pipe 2 includes, in order from the upstream side, a first branch point 2a where the primary branch pipe 3 branches, a second branch point 2b where the secondary branch pipe 6 branches, and the electrolytic treatment liquid discharged from the sub-electrolysis tank 7. The secondary electrolytic treatment liquid is a junction 2d where the secondary electrolytic treatment liquid is returned to the main pipe 2. Between the second branch point 2b and the junction 2d of the main pipe 2, an adjustment valve 2c for adjusting the flow rate of the raw water flowing through the main pipe 2 is provided.

The primary branch pipe 3 is a pipe that connects the first branch point 2 a of the main pipe 2 and the main electrolytic cell 5, and the primary branch pipe 3 includes the first branch point 2 a and the main electrolytic tank 5. A junction 3b is provided where hydrochloric acid supplied from the hydrochloric acid supply means 4 is added to the raw water. In the primary branch pipe 3, the raw water flows in a portion 3a on the upstream side (side connected to the first branch point 2a) of the junction 3b, and on the downstream side (side connected to the main electrolytic cell 5) of the junction 3b. In part 3c, hydrochloric acid-added raw water flows. A diluting water pump 3 d that sucks raw water at a desired flow rate from the main pipe 2 and sends it to the main electrolytic cell 5 is provided at a portion 3 a through which the raw water of the primary branch pipe 3 flows.
The hydrochloric acid supply means 4 includes a hydrochloric acid tank 4a for storing a hydrochloric acid aqueous solution, a hydrochloric acid supply pipe 4b connecting the hydrochloric acid tank 4a to the junction 3b of the primary branch pipe 3, and a hydrochloric acid aqueous solution from the hydrochloric acid tank 4a. There is provided a hydrochloric acid pump 4c that sucks and feeds it toward the main electrolytic cell 5 through the hydrochloric acid supply pipe 4b.
The primary branch pipe 3 serves as a hydrochloric acid-added raw water supply means that prepares hydrochloric acid-added raw water by mixing raw water supplied from the main pipe 2 and hydrochloric acid supplied from the hydrochloric acid supply means 4 and supplies it to the main electrolytic cell 5. Function.

The main electrolytic cell 5 is configured to electrolyze (electrolyze) the hydrochloric acid-added raw water supplied from the primary branch pipe 3. The main electrolytic cell 5 is not particularly limited, but as described above, it is preferable to employ a non-diaphragm electrolytic cell as the electrolytic cell and a bipolar electrode as the electrode.
The main electrolytic cell 5 is connected to a pipe 5 a that connects the main electrolytic cell 5 and the junction 6 b of the secondary branch pipe 6. The electrolytic treatment liquid discharged from the main electrolytic cell 5 after completion of the electrolytic treatment in the main electrolytic cell 5 is sent to the secondary branch pipe 6 through the pipe 5a.

The secondary branch pipe 6 is a pipe that connects the second branch point 2b of the main pipe 2 and the sub-electrolysis tank 7, and the secondary branch pipe 6 includes the second branch point 2b and the sub-electrolysis tank 7. In the middle, a junction 6b where the electrolytic treatment liquid discharged from the main electrolytic cell 5 joins is provided. The second branch point 2b of the main pipe 2 is provided downstream of the first branch point 2a. In the secondary branch pipe 6, raw water flows in a portion 6a on the upstream side (side connected to the second branch point 2b) of the junction 6b, and downstream of the junction 6b (side connected to the sub-electrolyzer 7). In the portion 6c, the intermediate diluted solution obtained by diluting the primary electrolytic treatment solution with raw water flows.
The secondary branch pipe 6 mixes the raw water supplied from the main pipe 2 and the primary electrolytic treatment liquid discharged from the main electrolytic tank 5 to form the intermediate dilution liquid, and the intermediate dilution supplied to the sub electrolytic tank 7 Functions as a means.

The sub-electrolysis tank 7 is configured to perform electrolytic treatment (electrolysis) on the intermediate diluent supplied from the secondary branch pipe 6. The sub electrolytic cell 7 is not particularly limited, but as described above, it is preferable to employ a non-diaphragm electrolytic cell as the electrolytic cell and a bipolar electrode as the electrode.
A pipe 7 a that connects the sub-electrolysis tank 7 and the junction 2 d of the main pipe 2 is connected to the sub-electrolysis tank 7. A junction 2d of the main pipe 2 is provided downstream of the second branch point 2b. The electrolytic treatment liquid (secondary electrolytic treatment liquid) discharged from the secondary electrolytic tank 7 after completion of the electrolytic treatment in the secondary electrolytic tank 7 is sent to the main pipe 2 through the pipe 7a and flows through the main pipe 2 there. It is designed to be diluted with raw water.
That is, the main pipe 2 on the downstream side of the second branch point 2b (hereinafter sometimes referred to as a downstream part of the main pipe) is supplied with a secondary electrolytic treatment liquid that is an electrolytic treatment liquid discharged from the sub electrolytic cell. It functions as final dilution means 8 for dilution with raw water.

The apparatus 1 for producing hypochlorous acid water having the above-described configuration operates as follows.
Raw water is poured into the main pipe 2, a part of the raw water is sucked into the primary branch pipe 3, and hydrochloric acid supplied from the hydrochloric acid supply means 4 is joined to the primary branch pipe 3 to prepare hydrochloric acid-added raw water. The hydrochloric acid-added raw water is supplied to the main electrolytic cell 5 where it is subjected to electrolytic treatment. In the main electrolytic cell 5, most (90% or more) of chlorine present as chlorine ions in the hydrochloric acid-added raw water is electrolytically oxidized. The electrolytic treatment liquid (primary electrolytic treatment liquid) generated in the main electrolytic tank 5 is discharged from the main electrolytic tank 5 and merges into the secondary branch pipe 6 through the pipe 5a, where the raw water flows in the secondary branch pipe 6. And diluted with. In the secondary branch pipe 6, the raw water branched from the second branch point 2b and the primary electrolytic treatment liquid are mixed and diluted. The diluted electrolytic treatment liquid (intermediate dilution liquid) is supplied to the sub-electrolysis tank 7 where it is subjected to electrolytic treatment. In the sub-electrolysis tank 7, the chlorine simple substance and hydrochloric acid remaining in the intermediate diluent are electrolytically oxidized to hypochlorous acid. The electrolytic treatment liquid (secondary electrolytic treatment liquid) generated in the sub-electrolysis tank 7 is discharged from the sub-electrolysis tank 7 and merges with the downstream portion 8 of the main pipe 2 through the pipe 7a and flows in the main pipe 2 there. Diluted by mixing with raw water.

According to the hypochlorous acid water production apparatus 1 of the present embodiment, after the hydrochloric acid-added raw water is electrolytically treated in the main electrolytic tank 5, the primary electrolytic treatment liquid is caused to flow into the secondary branch pipe 6 and mixed with the raw water. By intermediate dilution, chlorine alone remaining in the primary electrolytic treatment liquid can be reacted with water. Furthermore, the hydrochloric acid generated by the reaction between the chlorine alone and the water in the primary electrolytic treatment solution is electrolyzed in the sub-electrolysis tank 7, so that there is an appropriate effective chlorine concentration, and hydrochloric acid and chlorine alone remain extremely. It is possible to produce hypochlorous acid water that is easy to adjust to a slightly acidic range by dilution.
The secondary electrolytic treatment liquid discharged from the sub electrolysis tank 7 is returned to the main pipe 2, where it is mixed with raw water and diluted. The effective chlorine concentration of hypochlorous acid water can be adjusted to a concentration suitable for applications such as sterilization at the stage of dilution in the main pipe 2.
Raw water supplied to the primary branch pipe 3 toward the main electrolytic tank 5, raw water supplied to the secondary branch pipe 6 toward the sub electrolytic tank 7, and supplied to dilute the secondary electrolytic treatment solution Since both raw water is supplied from the main pipe 2, supply management of the raw water becomes easy, and the manufacturing apparatus can be configured more simply.

In the apparatus for producing hypochlorous acid water having the configuration shown in FIG. 1, as the main electrolytic cell 5 and the sub electrolytic cell 7, a partitionless electrolytic cell manufactured by Hokuetsu Co., Ltd. was used. Other equipment such as a pump and a regulating valve were also manufactured by Hokuetsu Co., Ltd.
RO water having a pH of 6.9 was passed through the main pipe 2 as raw water at a flow rate of 1200 L / h. The primary branch pipe 3 is fed with raw water having a flow rate of 150 ml / h by a diluting water pump 3d, and at a supply rate of 120 ml / h, hydrochloric acid having a concentration of 21% stored in a hydrochloric acid tank using a hydrochloric acid pump 4c. The primary branch pipe 3 was joined, and hydrochloric acid-added raw water was prepared and supplied to the main electrolytic cell 5. In the main electrolytic cell 5, the electrolysis voltage was set to 48V and the hydrochloric acid-added raw water was electrolyzed through a current of 1.8A. After completion of the electrolytic treatment, the primary electrolytic treatment liquid discharged from the main electrolytic cell 5 had an effective chlorine concentration of 710,000 ppm and a pH of 1.0.
The primary electrolytic treatment solution was diluted by feeding raw water with a flow rate of 30 L / h to the secondary branch pipe 6. The treatment liquid after the intermediate dilution had a pH of 3.1 and an effective chlorine concentration of 650 ppm. The treatment liquid after intermediate dilution was supplied to the sub-electrolysis tank 7 for electrolysis. The electrolysis conditions in the sub electrolysis tank 7 were an electrolysis voltage of 48 V and a current of 0.5 A. After the electrolytic treatment, the secondary electrolytic treatment solution discharged from the sub-electrolysis tank 7 had a pH of 4.2 and an effective chlorine concentration of 720 ppm. The secondary electrolytic treatment liquid was returned to the main pipe 2 and mixed with raw water flowing through the main pipe 2 to obtain slightly acidic hypochlorous acid water from the outlet of the main pipe 2 at a flow rate of 1200 L / h. The slightly acidic hypochlorous acid water produced in this way has a pH of 5.8 and an effective chlorine concentration of 18 ppm. The effective chlorine concentration is high enough to be suitable for uses such as sterilization, and the pH is in a slightly acidic range. It was adjusted appropriately.

  The hypochlorous acid water produced by the present invention can be used for various purposes such as sterilization of foods, instruments, equipment, water, etc., air washing, deodorization and the like.

It is a schematic block diagram which shows one example of the manufacturing apparatus of hypochlorous acid water based on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Hypochlorous acid water manufacturing apparatus, 5 ... Main electrolytic cell, 6 ... Secondary branch piping (intermediate dilution means), 7 ... Sub electrolytic cell, 8 ... Final dilution means.

Claims (5)

  A main electrolytic cell for electrolytically treating hydrochloric acid-added raw water obtained by adding hydrochloric acid to raw water, an intermediate diluting means for diluting the primary electrolytic treated liquid discharged from the main electrolytic cell with the raw water, and this intermediate dilution An apparatus for producing hypochlorous acid water, comprising: a sub-electrolysis tank that electrolyzes the intermediate diluted solution diluted by the means.   The apparatus for producing hypochlorous acid water according to claim 1, further comprising a final diluting means for diluting a secondary electrolytic treatment liquid, which is an electrolytic treatment liquid discharged from the sub-electrolysis tank, with raw water. .   A primary electrolytic treatment step for electrolytically treating hydrochloric acid-added raw water, an intermediate dilution step for diluting the primary electrolytic treatment solution obtained by the primary electrolytic treatment step with raw water, and an intermediate dilution obtained by the intermediate dilution step A method for producing hypochlorous acid water, comprising a secondary electrolytic treatment step of electrolytically treating a liquid.   The production of hypochlorous acid water according to claim 3, further comprising a final dilution step of diluting a secondary electrolytic treatment solution obtained by the secondary electrolytic treatment step with raw water. Method.   The method for producing hypochlorous acid water according to claim 3 or 4, wherein an effective chlorine concentration of the intermediate dilution electrolytic treatment liquid is set to 1000 ppm or less.

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