JP2016117048A - Production method and production apparatus of hypochlorite solution - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method and a production apparatus of a hypochlorite solution that completely solve the problems in an electrolytic method and a two-liquid method for lowering a pH of a sodium hypochlorite aqueous solution, such as a quality problem caused by nonuniform chemical reaction and a degradation problem in long-term storage.SOLUTION: A production apparatus of a hypochlorite solution includes an in-line mixer 1 to produce a mixed solution of city water and sodium hypochlorite, a high pressure metering pump 5 connected to the outlet side of the in-line mixer 1 to receive the mixed solution, an atomizing nozzle 6 connected to a discharge port of the high pressure metering pump 5 to form fine particles of the mixed solution by uniformly atomizing the discharged mixed solution, and a weak acidic ion exchange resin column 7 to receive the fine particles of the mixed solution from the atomizing nozzle 6 and to produce a hypochlorite solution by ion exchange.SELECTED DRAWING: Figure 1

Description

The present invention relates to a hypochlorous acid water production method and production apparatus, and more specifically,
The present invention relates to a hypochlorous acid water manufacturing method and a manufacturing apparatus capable of in-line processing without fear of air mixing that causes deterioration of hypochlorous acid water in all processes for manufacturing hypochlorous acid water.

  An aqueous solution of hypochlorite such as sodium hypochlorite has been used for sterilization of tap water and food. In general, a commercially available sodium hypochlorite aqueous solution is strongly alkaline having a pH of about 12, and even when diluted to a residual chlorine concentration (100 to 200 ppm) necessary for use as sterilizing water, it can only be lowered to about pH 8. . Under this pH value, sodium hypochlorite is dissociated into sodium ions Na and hypochlorite ions in water, and hardly forms hypochlorous acid. That is, since most of the residual chlorine exists in the form of hypochlorite ions, the sterilizing power is weak.

  Therefore, it is necessary to lower the pH value of dilute sodium hypochlorite water to about pH 7 to 3 so that residual chlorine exists in the form of hypochlorous acid. As a method for lowering the pH of the sodium hypochlorite aqueous solution, an electrolytic method, a two-component method, and the like are known.

  However, in the case of the electrolysis method, an apparatus and an electrode equipped with an electrolytic cell are necessary, and there is a problem that the maintenance is expensive, and only low-concentration weakly acidic hypochlorous acid can be produced. There is a limit that cannot be done. On the other hand, in the case of the two-component method, the pH is adjusted to the acidic side by mixing an aqueous sodium hypochlorite solution with hydrochloric acid, and the pH is adjusted with an acid such as hydrochloric acid. A process of mixing sodium and acid is required, which causes a safety problem. Particularly, chlorine gas is generated by mixing sodium hypochlorite and hydrochloric acid, which is very dangerous. Therefore, a production method that does not involve the danger of chlorine gas generation has been desired.

  As a method for lowering the pH of an aqueous sodium hypochlorite solution without using hydrochloric acid, Patent Document 1 (JP-A-6-206076) and Patent Document 2 (JP-A 2009-274950) disclose ion exchange resins. A method of use is disclosed.

  Among these, the method disclosed in Patent Document 1 uses a solution whose pH is lowered by ion exchange of water containing a cation such as a mineral with a hydrogen-substituted ion exchange resin instead of hydrochloric acid, This is to lower the pH value of the aqueous sodium hypochlorite solution. However, in the case of this method, after the obtained acidic solution is mixed with sodium hypochlorite, the pH is lowered to a value at which chlorine gas can be generated, so that generation of chlorine gas is unavoidable. In particular, when the total amount is ion-exchanged, the pH is supposed to drop to 2.7. Therefore, after obtaining an acidic solution by ion exchange, a step of mixing with sodium hypochlorite is required, and the labor is reduced. Take it.

  On the other hand, Patent Document 2 discloses a method for preparing a hypochlorous acid solution that is intended to produce hypochlorous acid without containing any salts. In this method, first, a sodium hypochlorite solution is treated with a hydrogen-substituted ion exchange resin to replace metal ions with hydrogen ions, and then the resulting solution is treated with an anion-exchange resin to produce chlorine. A step of replacing the ions with hydroxide ions. Therefore, since it is necessary to treat with two types of ion exchange resins, this method is also troublesome and it is difficult to adjust the pH of hypochlorous acid. Further, it is disclosed that when a sodium hypochlorite solution is treated with a hydrogen-substituted ion exchange resin, the liquidity becomes strongly acidic and the bactericidal effect is reduced. In this case, generation of chlorine gas is unavoidable. Become.

  In view of such circumstances, Patent Document 3 (Japanese Patent Application Laid-Open No. 2014-43392) discloses an apparatus and method for producing a hypochlorous acid aqueous solution without using an acid and substantially without generating chlorine gas. No. 1), "Manufacturing method including a step of treating a hypochlorite solution with a weakly acidic ion exchanger having a buffering action at a pH higher than that at which chlorine gas is generated", and "pH at which chlorine gas is generated The proposal of "the apparatus for producing weakly acidic hypochlorous acid comprising a weakly acidic ion exchanger having a buffering action" has been made.

  However, in the case of the manufacturing method and the manufacturing apparatus according to this proposal, an apparatus and a method for manufacturing a hypochlorous acid aqueous solution without using an acid and without substantially generating chlorine gas. The solution to the problem of manufacturing quality resulting from the heterogeneity of the chemical reaction and the problem of deterioration in long-term storage, which are problems of the two-component method and the electrolytic method, are not considered at all.

That is, the following points are mentioned as risks of the electrolytic method and the two-component method.
• The dilution accuracy is not sufficient (1.0 Mpa or less ± 1.0-5.0%, the accuracy depends on the flow rate).
-Heterogeneous.
-The mixing of air in the stirring process causes the promotion of hypochlorous acid decomposition.
・ Automatic measurement of sodium hypochlorite concentration is not possible.

Moreover, the following problems are pointed out about pH adjustment by an ion exchange resin.
In the case where hypochlorous acid is generated by ion exchange with a hydrogen-type ion exchange resin (Patent Document 1), performance management cannot be performed.
-When the total hardness of tap water is unknown or fluctuates, and when the concentration of sodium hypochlorite serving as the stock solution fluctuates due to inaccuracy or deterioration, the calculation accuracy of the total amount of ion exchange is poor.
・ When hypochlorous acid is decomposed by light, air, heat, or organic matter, it is decomposed into hydrochloric acid and oxygen.

JP-A-6-206076 JP 2009-274950 A JP 2014-43392 A

  As described above, in the conventionally proposed apparatus and method for producing an aqueous hypochlorous acid solution without generating chlorine gas, electrolysis for lowering the pH of the aqueous sodium hypochlorite solution is provided. The solution of the problem of manufacturing quality caused by the heterogeneity of chemical reaction and the problem of deterioration in long-term storage, which are problems of the method and the two-component method, have not been considered at all.

  Therefore, the present invention is a problem of manufacturing quality caused by non-uniformity of chemical reaction, which is a problem of electrolytic method and two-component method for lowering the pH of sodium hypochlorite aqueous solution, and deterioration in long-term storage. It is an object of the present invention to provide a hypochlorous acid water production method and production apparatus that solve all the problems.

  The invention according to claim 1 for solving the above problems includes a step of generating a mixed solution of tap water and sodium hypochlorite, a step of atomizing the mixed solution to generate a atomized solution, and the fine particles. And a step of producing hypochlorous acid water by ion-exchange of the hydrolyzed mixed solution.

  Moreover, the invention which concerns on Claim 2 for solving the said subject is the process of connecting a water pipe and a sodium hypochlorite tank to an in-line mixer, the tap water supplied from the said water pipe, and the said hypochlorous acid Mixing sodium hypochlorite supplied from a sodium tank in the in-line mixer to generate a mixture, introducing the mixture into the high-pressure metering pump from the in-line mixer, and discharging from the high-pressure metering pump Producing a fine particle of the mixed solution by passing the mixed solution through a atomizing nozzle, and ion-exchange the fine particles of the mixed solution in a two-layer weakly acidic ion exchange resin column to produce hypochlorous acid water A process for producing hypochlorous acid water, comprising the steps of:

  Further, the invention according to claim 4 for solving the above-mentioned problem is connected to a water pipe and a sodium hypochlorite tank, and tap water from the water pipe and hypochlorous from the sodium hypochlorite tank. An in-line mixer that generates a mixed solution of sodium chlorate, a high-pressure metering pump that receives the mixed solution from the in-line mixer, and the mixture that is connected to a discharge port of the high-pressure metering pump and is discharged from the high-pressure metering pump A fine atomizing nozzle that uniformly atomizes a liquid to generate a finely mixed liquid, and a weakly acidic ion exchange resin column that receives the atomized mixed liquid from the atomizing nozzle and ion-exchanges to produce hypochlorous acid water Is a hypochlorous acid water production apparatus consisting of

  In one embodiment, the sodium hypochlorite tank is connected to the in-line mixer via a plunger pump.

  In one embodiment, the atomization nozzle has a through structure in which a narrow-diameter front nozzle and a wide-diameter rear nozzle are connected in series. The weakly acidic ion exchange resin column is a weakly acidic ion exchange resin column having a two-layer structure in which a sodium ion exchange resin layer 7a is disposed on the inner side and a hydrogen ion exchange resin layer 7b is disposed on the outer side.

  The present invention is as described above, which is a problem such as an electrolytic method or a two-component method for lowering the pH of an aqueous sodium hypochlorite solution, a problem of production quality resulting from non-uniformity of chemical reaction, and a long-term There is an effect of obtaining a hypochlorous acid water production method and production apparatus that do not have a problem of deterioration in storage.

It is a schematic block diagram of the whole hypochlorous-acid water manufacturing apparatus concerning this invention.

  A mode for carrying out the present invention will be described with reference to the accompanying drawings. The method for producing hypochlorous acid water according to the present invention includes a step of producing a mixed solution of tap water and sodium hypochlorite, a step of atomizing the mixed solution to produce fine particles, and a step of producing fine particles of the mixed solution. And a step of producing hypochlorous acid water by ion exchange.

  More specifically, the method for producing hypochlorous acid water according to the present invention includes a step of connecting a water pipe and a sodium hypochlorite tank to an in-line mixer, a tap water supplied from the water pipe, and the hypochlorous acid. Mixing sodium hypochlorite supplied from a sodium acid tank in the in-line mixer to generate a mixed solution, introducing the mixed solution from the in-line mixer into a high-pressure metering pump, and from the high-pressure metering pump The step of passing the liquid mixture to be discharged through a atomization nozzle to generate fine particles of the liquid mixture, and ion exchange of the fine particles of the liquid mixture in a two-layer weakly acidic ion exchange resin column to produce hypochlorous acid water. And a manufacturing process.

  Moreover, the hypochlorous acid water manufacturing apparatus based on this invention is for implementing the said manufacturing method, Comprising: As FIG. 1 shows, water pipe 1 and sodium hypochlorite tank 2 are provided in the inlet side. Is connected to the in-line mixer 4 for generating a mixed solution of tap water supplied from the water pipe 1 and sodium hypochlorite supplied from the sodium hypochlorite tank 2 and the outlet side of the in-line mixer 4 The high-pressure metering pump 5 into which the mixed solution is introduced from the in-line mixer 4 and the discharge port of the high-pressure metering pump 5 are connected to the discharge port of the high-pressure metering pump 5 to uniformly atomize the mixed solution. A fine atomizing nozzle 6 that generates fine particles, and a two-layer weakly acidic ion exchange resin column 7 that receives the fine particles of the mixed solution from the atomizing nozzle 6 and produces ion hypochlorite water by ion exchange. In constructed.

  The in-line mixer 4 is a static mixer for homogeneously mixing tap water from the water pipe 1 and sodium hypochlorite from the sodium hypochlorite tank 2. Needless to say, the static mixer is a non-powered mixer in which a plurality of curved elements are arranged in a cylinder, and uniformly mixes and homogenizes the liquid by the mixing principle of division, conversion and inversion.

  The sodium hypochlorite tank 2 is connected to the in-line mixer 4 via the plunger pump 3. As the plunger pump 3, a small valveless plunger pump with a small number of parts and easy maintenance is recommended. And the discharge pressure is set higher than the pressure of tap water.

  The high-pressure metering pump 5 has a atomizing nozzle 6 attached to its discharge port, and dispenses the liquid mixture fed from the in-line mixer 4 toward the atomizing nozzle 6 at a pressure of about 1 to 5 MPa.

  The atomization nozzle 6 has a through-type structure in which a narrow-diameter front nozzle and a wide-diameter rear nozzle are continuously provided. Turbulence is generated in the front nozzle by a cavitation effect, and the fluid jet is inherent in the rear nozzle. It is atomized by generating turbulent flow due to instability. By generating strong shearing with this atomization nozzle 6, homogenization is achieved by dispersion (μm) from dispersion (μm) by turbulent flow stronger than mixing.

  Next, the fine particles of the mixed solution are passed through the weakly acidic ion exchange resin column 7 to be ion-exchanged with a hydrogen type ion exchange resin (for example, a separation constant pKa = 5.3) to generate hypochlorous acid. Is done.

  As the weakly acidic ion exchange resin column 7, in consideration of the case where the total hardness of tap water is high (hard water), a sodium ion exchange resin layer 7a is arranged on the inner side, and a hydrogen ion exchange resin layer 7b is arranged on the outer side. It is preferable to use a weakly acidic ion exchange resin column having a two-layer structure (see FIG. 1). In the case of this weakly acidic ion exchange resin column 7 having a two-layer structure, first, water softening treatment is performed in the inner sodium-type ion exchange resin layer 7a, and then pH adjustment is performed in the outer hydrogen-type ion exchange resin layer 7b. Will be done. The concentration of sodium hypochlorite serving as the stock solution is desirably 3% or 6% with little deterioration. This makes it possible to calculate the ion exchange amount from a stable stock solution.

  As described above, in the case of the conventional hypochlorous acid water production apparatus, the measurement accuracy is 3% or more because it is based on the instantaneous measurement of the flow rate of water supply in both the two-liquid method and the electrolysis method. The dilution accuracy was not sufficient. Further, if the sodium hypochlorite stock solution is 6% or more, gaseous oxygen is generated when it is decomposed, which causes a flow meter error. Therefore, in the present invention, preferably, 3% sodium hypochlorite that suppresses gas generation is used, and the sodium hypochlorite concentration is automatically measured by specific gravity measurement.

  In addition, a volumetric metering pump is used to achieve a dilution accuracy of ± 0.5% depending on the number of revolutions of the inverter.

  A particularly prominent problem in the electrolysis method is that the oxidant concentration near the electrode becomes almost zero, and the reaction becomes saturated. Similarly, in the case of the two-component method, if the stirring is not performed, the neutralization reaction by the acid remains only in the region where the acid is injected. On the other hand, even if a stirrer is introduced to promote the reaction and dispersion, if optimum stirring conditions are not set, air will be mixed in, and this will promote the decomposition of hypochlorous acid. In this respect, in the case of the present invention, the problem of air mixing does not occur because of inline processing.

The characteristics of the present invention are summarized as follows.
1) The dispersion chemical reaction is promoted by the shearing force generated by the combination of the atomizing nozzle 6 and the high-pressure metering pump 5.
2) Dilution (± 0.5%) with high repeatability by the high-pressure metering pump 5 can be realized.
3) By using the weak acid ion exchange resin column 7 having a two-layer structure, the total hardness of the raw water is adjusted with the sodium type weak acid ion exchange resin 7a, and then the hydrogen type weak acid ion exchange resin 7b (dissociation multiplier pKa = The pH can be adjusted according to 5.3). Thereby, since the ion selectivity is Ca> Na, the problem that Na adsorption reaction does not proceed unless the raw water Ca is removed is solved.
4) Mixing of air was unavoidable in the stirring by the conventional method, which led to deterioration of hypochlorous acid water. In the present invention, the combination of the atomizing nozzle 6 and the high-pressure metering pump 5, The weakly acidic ion exchange resin column 7 having a two-layer structure enables in-line processing without air mixing from dilution of sodium hypochlorite to pH adjustment.

DESCRIPTION OF SYMBOLS 1 Water supply pipe 2 Sodium hypochlorite tank 3 Plunger pump 4 In-line mixer 5 High pressure metering pump 6 Atomization nozzle 7 Weakly acidic ion exchange resin column 7a Sodium type ion exchange resin 7b Hydrogen type ion exchange resin

Claims (7)

  A step of producing a mixture of tap water and sodium hypochlorite, a step of atomizing the mixture to produce an atomized solution, and ion exchange of the atomized mixture to produce hypochlorite water A process for producing hypochlorous acid water, comprising the step of: Connecting the water pipe and sodium hypochlorite tank to the in-line mixer;
Mixing tap water supplied from the water pipe and sodium hypochlorite supplied from the sodium hypochlorite tank in the in-line mixer to generate a mixed solution;
Introducing the mixed liquid from the in-line mixer into a high-pressure metering pump;
Generating fine particles of the liquid mixture by passing the liquid mixture discharged from the high-pressure metering pump through an atomization nozzle;
A process for producing hypochlorous acid water, comprising the step of ion-exchanging fine particles of the mixed solution in a weakly acidic ion exchange resin column to produce hypochlorous acid water.   The method for producing hypochlorous acid water according to claim 2, wherein the weakly acidic ion exchange resin column has a two-layer structure in which an inner layer is a sodium ion exchange resin and an outer layer is a hydrogen ion exchange resin. A water pipe and a sodium hypochlorite tank are connected to the inlet side to generate a mixture of tap water supplied from the water pipe and sodium hypochlorite supplied from the sodium hypochlorite tank. An inline mixer,
A high-pressure metering pump connected to the outlet side of the in-line mixer and introduced with a mixed liquid from the in-line mixer;
A atomizing nozzle connected to the discharge port of the high-pressure metering pump to uniformly atomize the liquid mixture discharged from the high-pressure metering pump to generate fine particles of the liquid mixture;
An apparatus for producing hypochlorous acid water, comprising: a weakly acidic ion exchange resin column that receives fine particles of the mixed liquid from the atomization nozzle and ion-exchanges to produce hypochlorous acid water.   The apparatus for producing hypochlorous acid water according to claim 4, wherein the sodium hypochlorite tank is connected to the in-line mixer via a plunger pump.   6. The hypochlorous acid water production apparatus according to claim 4, wherein the atomization nozzle has a through-type structure in which a narrow-diameter front nozzle and a wide-diameter rear nozzle are connected in series.   The hypochlorous acid water production according to any one of claims 4 to 6, wherein the weakly acidic ion exchange resin column has a two-layer structure in which an inner layer is a sodium ion exchange resin and an outer layer is a hydrogen ion exchange resin. apparatus.

Images