JP7368658B1 - Acidic hypochlorous acid water production equipment and acidic hypochlorous acid water production method - Google Patents

Abstract

One aspect of the present invention is an apparatus that includes a plurality of ion exchange columns and produces weakly acidic hypochlorous acid water from a sodium hypochlorite aqueous solution by an ion exchange method. While reducing the risk of chlorine gas being generated due to erroneous mixing with aqueous sodium chloride solution, the number of structural members is reduced to suppress device costs. The acidic hypochlorous acid water production apparatus according to one aspect of the present invention includes chemical supply pipes (EA-1 to EA-n) that supply an aqueous sodium hypochlorite solution as a raw material, and a strong acid aqueous solution for column regeneration. The acid supply piping (EB-1 to EB-n) and the water supply piping (EF-1 to EF-n) that supplies water for internal cleaning are all merged to form n dual-purpose piping ( E1 to En) and then connected to the columns (C1 to Cn), and at the same time, the confluence is where either the chemical supply pipe or the acid supply pipe and the water supply pipe join, and the confluence is downstream of the confluence. , the remaining acid supply pipes or chemical solution supply pipes are arranged in the order in which they merge. In addition, the discharge side piping (G/H1 to G/Hn) is a branch of the acid waste liquid piping (HB-1 to HB-n), and the hypogasous waste liquid piping (HA-1 to HA- It is preferable to branch into the treated chemical liquid transfer pipes (G1 to Gn).

Description

The present invention relates to an apparatus and method for efficiently producing weakly acidic hypochlorous acid water using an aqueous solution of hypochlorite as a raw material.

Aqueous solutions of hypochlorites, such as sodium hypochlorite, are used as disinfectants in a wide range of fields. It is known that the bactericidal effect varies greatly depending on the pH of the solution.

Even if an aqueous sodium hypochlorite solution is directly diluted to 50 to 100 ppm, which is commonly used as a disinfectant, the pH will only drop to about 8.5 to 9.5. Under such alkaline conditions, most of the ions are in the form of hypochlorite ions (OCl ⁻ ), which has a low bactericidal effect. In addition, sodium hypochlorite has a high pH and strongly irritates the skin, so it cannot be used directly on humans or livestock. In order to increase the bactericidal effect, it is necessary to adjust the pH to the acidic side and change the state to hypochlorous acid (HClO) (in this case, even if hypochlorite is obtained by dissolving it, the next It is called chlorite water (or aqueous solution). The bactericidal effect of hypochlorous acid is said to be about 80 times that of hypochlorite ion.

Hypochlorous acid water with a pH of about 3.5 to 6.5 is attracting attention because it mainly exists as hypochlorous acid (HClO), and is used in medical, dental, agricultural, and food processing industries. It is used as a disinfectant in various fields. In recent years, it has come to be used for sterilization purposes in public facilities such as nursing care facilities, educational facilities, and commercial facilities, as well as in general households, and its consumption is increasing year by year.

One method for producing such weakly acidic hypochlorous acid water is to pass an aqueous solution of hypochlorite through a container (column) filled with a weakly acidic ion exchange resin. A method and apparatus for producing an aqueous chlorous acid solution have been proposed (see, for example, Patent Document 1).

Incidentally, ion exchange columns are used in various fields such as purification of water and the like and pH adjustment as described above. Of course, one ion exchange column cannot perform ion exchange indefinitely, so ion exchange resins that have undergone a certain amount of ion exchange (reaching flow-through exchange capacity) should be replaced with new ones, and used ones should be replaced with new ones. , it is necessary to discard or regenerate. A common method for regenerating weakly acidic ion exchange resins is to flow an acid aqueous solution, and a strong acid aqueous solution such as hydrochloric acid is commonly used due to its regeneration efficiency.

To regenerate the ion exchange resin, there is a method of removing the entire column from the device and flowing a strong acid aqueous solution in another location, but it is also possible to regenerate the ion exchange resin by installing multiple ion exchange columns in the device and performing ion exchange treatment on one column. However, there is also a method of regenerating the ion exchange resin in another ion exchange column.

International Publication No. 2011/136091

Hiroshi Shimizu, “Ion Exchange Resin Applications I Overview (Part 2)”, Electrochemical Society of Japan, Electrochemistry and Industrial Physical Chemistry, Vol. 33, No. 3, 1966, p. 243-246

The above method of equipping a single device with multiple ion exchange columns and performing ion exchange treatment on one column while performing regeneration treatment on other columns improves productivity as there is no need to remove or transport the columns. Are better.

However, when the sodium hypochlorite aqueous solution is made strongly acidic, molecular chlorine (Cl ₂ ) is generated. Therefore, there was a risk in handling large amounts of sodium hypochlorite and strong acid at the same time in one device.

Accordingly, an object of the present invention is to provide a manufacturing apparatus in which there is little possibility that a sodium hypochlorite aqueous solution and a strong acid aqueous solution will mix, and which has as few structural members as possible (=low equipment cost).

The following manufacturing apparatus is provided to solve the above problem.

That is, the present invention
a sodium hypochlorite aqueous solution storage tank (A);
A strong acid aqueous solution storage tank (B),
A plurality of (n) ion exchange columns (C ₁ to C _n ) filled with a weakly acidic cation exchange resin,
a recovered liquid storage tank (D) that stores the ion-exchanged chemical liquid;
Chemical solution supply piping (E _A-1 to E _A-n ) that supplies a chemical solution from the sodium hypochlorite aqueous solution storage tank (A) to each ion exchange column (C ₁ to C _n );
Acid supply piping (E B _-1 to E _B-n ) that supplies a strong acid aqueous solution from the strong acid aqueous solution storage tank (B) to each ion exchange column (C ₁ to C _n );
Water supply piping (E _F-1 to E F _-n ) that supplies water from the water supply source (F) to each ion exchange column (C ₁ to C _n ),
The chemical solution supply pipes (E _A-1 to E _A-n ), the acid supply pipes (E _B-1 to E _B-n ), and the water supply pipes (E _F-1 to E _F-n ) merge in the middle. As a result, there are n supply pipes (E ₁ to E _n ) each serving as a chemical solution supply pipe, an acid supply pipe, and a water supply pipe, and each of these supply pipes is connected to each ion exchange column (C ₁ to C _n ) is connected to the supply port of
And the said confluence is between either the chemical solution supply piping (E _A-1 to E _A-n ) or the acid supply piping (E _B-1 to E _B-n ) and the water supply piping (E _F-1 to E _F -n). _-n ), and the remaining acid supply pipes (E _B-1 to E _B-n ) or chemical solution supply pipes (E _A-1 to E _A-n ) join downstream of the merging point. It becomes,
Furthermore, each pipe (G/H ₁ to G/H _n ) is connected to the outlet of each ion exchange column (C ₁ to C _n ), and each pipe is connected to the recovered liquid storage tank (D). It is branched into treated chemical liquid transfer piping (G ₁ to G _n ) for transferring the ion-exchanged chemical liquid and waste liquid piping (H ₁ to H _n ) for transferring the liquid to be disposed of. and
The processed chemical liquid transfer pipes (G ₁ to G _n ) after the branching are merged to form a single processed chemical liquid transfer pipe (G), and the processed chemical liquid transfer pipe (G ) is an acidic hypochlorous acid water production apparatus in which a water supply pipe (I) that supplies water from a water supply source (F) is further joined.

By using the production equipment of the present invention, acidic hypochlorous acid water can be produced efficiently and with high productivity without requiring excessive equipment manufacturing costs and greatly reducing the risk of accidentally generating chlorine. can do.

FIG. 2 is a schematic diagram showing an embodiment of the production apparatus of the present invention in which there are two ion exchange columns.

The present invention relates to an apparatus for producing acidic hypochlorous acid water from a sodium hypochlorite aqueous solution by a so-called ion exchange method. Therefore, the manufacturing apparatus of the present invention includes a sodium hypochlorite aqueous solution storage tank (A) for storing the sodium hypochlorite aqueous solution used as the raw material, and a weakly acidic cation for exchanging sodium ions into hydrogen ions. It has an ion exchange column (C) filled with exchange resin.

As the sodium hypochlorite aqueous solution to be treated, any known aqueous solution can be used without any particular restriction, and it is commercially available for various purposes, so you can use it, but considering production efficiency, it is better to have a higher concentration. Specifically, the available chlorine concentration is preferably 0.5% by mass or more, preferably 0.8% by mass or more, and preferably 1.0% by mass or more. Although it depends on the use of the produced acidic hypochlorous acid water, it is preferable to use one with a low sodium chloride content, and one with a sodium chloride concentration of 1/3 or less of the effective chlorine concentration [mass%] (generally low-salt hypochlorous acid water). 1/6 or less (generally called special grade sodium hypochlorite for water use) is preferable.

Known weakly acidic cation exchange resins to be filled in the ion exchange column can be used without particular limitation, but those having carboxyl groups as ion exchange groups are preferred. Further, the weakly acidic cation exchange resin may be of any type, such as porous type, gel type, or macroporous type. The reason why a weakly acidic cation exchange resin is used as the cation exchange resin is to prevent the pH of the acidic hypochlorous acid water obtained by treatment (flow) from becoming too low.

The production apparatus of the present invention has a plurality of (n) ion exchange columns in order to perform the ion exchange reaction and the regeneration of the ion exchange resin in one apparatus without having to remove the ion exchange column from the apparatus. has. Here, n is an integer of 2 or more.

Hereinafter, the manufacturing apparatus of the present invention will be described in more detail with reference to the drawings, in the case where the number of ion exchange columns (C) is two. Note that even when the number of ion exchange columns (C) is three or more, the basic configuration of piping etc. and the method of use are the same, except that the number of branches and merging increases according to the number of columns.

In Figure ₁ , chemical solution _supply piping ( E _A ) is provided. The piping may be two completely independent systems from the beginning, but as shown in the embodiment shown in Fig. 1, one chemical liquid supply system extends from the sodium hypochlorite aqueous solution storage tank (A). The pipe is branched in the middle to form two chemical solution supply pipes (E _A-1 , E _A-2 ), which serve as the first ion exchange column (C ₁ ) and the second ion exchange column (C ₂ ), respectively. It is preferable to connect it to. In the illustrated embodiment, a pump for boosting the pressure is provided in the supply system piping such as the chemical liquid supply piping, but by branching one piping in the middle in this way, one pump can be installed before the branching. It only needs to be installed, and equipment costs can be reduced. In addition, in the embodiment of FIG. 1, on-off valves (VA _-1, VA _-2 ) are installed downstream of the branched portion, so that the supply of chemical solutions to each ion exchange column can be controlled. .

The piping is also provided with another on-off valve (V _C-1 ) before the connection to the column. This opening/closing valve ( _VC-1 ) is linked with a liquid level gauge (K ₁ ) installed in the column, and has the role of controlling the liquid level in the column to be constant (opening/closing control). or opening control). Many weakly acidic cation exchange resins have a large volume change between acid and salt forms, so even when the volume expands, the entire amount of filled cation exchange resin remains below the liquid level. It is intended to control the

Below, the situation in which ion exchange treatment is performed in the first ion exchange column (C ₁ ) will be explained first. When performing ion exchange treatment in the first ion exchange column (C ₁ ), the on-off valve (V _A-1 ) is opened, the on-off valve (V _A-2 ) is closed, and the branched Among the pipes, only the chemical liquid supply pipe (E _A-1 ) connected to the first ion exchange column (C ₁ ) side is configured to allow the chemical liquid to pass through. The amount of chemical solution supplied can be determined as appropriate, and can be set, for example, to an amount such that the space velocity SV [1/h] is about 0.1 to 20, preferably about 3 to 15. Note that the space velocity SV is calculated as SV=R/V, where the volume of the packed bed of the weakly acidic cation exchange resin is V [L] and the flow rate of the processing liquid is R [L/h]. .

When the chemical solution is supplied to the ion exchange column (C ₁ ), some of the sodium ions in the sodium hypochlorite aqueous solution are exchanged into hydrogen ions by the weakly acidic cation exchange resin packed there, and the sodium ions are passed through. The liquid properties of the (ion-exchanged) chemical solution are converted to acidic, that is, to acidic hypochlorous acid water.

The chemical solution (acidic hypochlorous acid water) treated in the ion exchange column (C ₁ ) is transferred from the outlet of the ion exchange column (C ₁ ) to the recovered liquid storage tank (D) through piping. . In the production apparatus of the present invention, the piping is a piping (G/H ₁ ) that is shared with a piping for flowing waste liquid (described later) at the outlet of the ion exchange column (C ₁ ); It branches into a treated chemical liquid transfer pipe (G ₁ ) and a waste liquid pipe (described later). The acidic hypochlorous acid water obtained by the ion exchange treatment is of course flowed to the treated chemical liquid transfer pipe (G ₁ ) side.

Further, the treated chemical liquid transfer pipe (G ₁ ) merges with the treated chemical liquid transfer pipe (G ₂ ) from the other ion exchange column (C ₂ ), and becomes one processed chemical liquid transfer pipe (G). After that, it is connected to the collected liquid storage tank (D).

Furthermore, in the illustrated embodiment, a metering pump is provided in the shared pipe (G/H ₁ ) to control the amount of liquid flowing through the column.

Considering the efficiency of the ion exchange treatment, it is preferable that the sodium hypochlorite aqueous solution passed through the ion exchange column (C ₁ ) be concentrated, but when storing (storing) the ion exchange treated chemical solution, storage stability is required. The lower the concentration of the treated chemical solution, the better the properties. Therefore, in the manufacturing apparatus of the present invention, a water supply pipe (I) that supplies water from a water supply source (F) joins the treated chemical liquid transfer pipe (G). As shown in the figure, the water supply pipes (I) are joined after the treated chemical liquid transfer pipes (G ₁ , G ₂ ) are combined to form a single pipe. The piping (I) can be made into one piece.

Tap water, ion-exchange water, distilled water, ultra-pure water, etc. can be used as the water to be supplied, but from the perspective of the balance between impurity content and economical efficiency, ion-exchange water is recommended, and ultra-pure water is recommended if storage stability is more important. Preferably, pure water is used.

Therefore, the water supply source (F) may be selected according to the type of water to be supplied. For example, if ion-exchanged water is used, an ion-exchanged water production device or one produced using the same device can be used. An ion-exchanged water storage tank can be used to store ion-exchanged water. Similarly, in the case of ultrapure water, an ultrapure water production device or an ultrapure water storage tank can be employed. The manufacturing apparatus of the present invention may include a water supply source (F) as one of its constituent members, or may be connected to a water supply source (F) provided as a constituent member outside the manufacturing apparatus.

Further, the dilution ratio can be determined as appropriate, but it should be approximately 0.03 to 0.5% by mass in terms of effective chlorine concentration. Here, the effective chlorine concentration of sodium hypochlorite or acidic hypochlorous acid means the concentration calculated by converting the oxidizing power of hypochlorous acid into chlorine equivalent, and the concentration is equimolar to the hypochlorous acid it contains. It is expressed as the mass concentration of chlorine molecules. In the present invention, the effective chlorine concentration refers to a value measured by iodometric titration.

As the sodium hypochlorite aqueous solution is passed through (ion exchange treatment), the proportion of the salt type of the weakly acidic cation exchange resin in the ion exchange column (C ₁ ) gradually increases. Therefore, the pH of the liquid discharged from the column increases. When the pH of the liquid to be treated discharged from the column exceeds a predetermined value (reaches a breakthrough point), the passage of the aqueous sodium hypochlorite solution is stopped. The pH can be easily determined by installing a pH meter (J ₁ ) near the column outlet. Depending on the target pH range of acidic hypochlorous acid water to be produced, the breakthrough point can be set as appropriate, and any pH of approximately pH 6.5 or lower can be selected, and pH 3.5 The following are preferred.

The liquid flow is stopped when the breakthrough point is reached by not only stopping the liquid feeding pump (metering pump) but also by closing the on-off valve ( _VA-1 ).

Since the manufacturing apparatus of the present invention is equipped with a plurality of ion exchange columns, even after the treatment in the first ion exchange column (C ₁ ) reaches its limit, the flow path of the chemical solution is transferred to the second ion exchange column (C _{2 )} . ) side, acidic hypochlorous acid water can be manufactured continuously over time. That is, after closing the on-off valve (V _A-1 ), the on-off valve (V _A-2 ) may be opened so that the aqueous sodium hypochlorite solution flows toward the chemical supply pipe (E _A-2 ). This allows the ion exchange treatment to be continued in the same way using the ion exchange column (C ₂ ).

On the other hand, a weakly acidic cation exchange resin that has reached its breakthrough point (reached its flow-through exchange capacity) can be treated by passing a strong acid aqueous solution such as hydrochloric acid through it to return the salt-formed cation exchange groups to the acid form. Can be played. In the production apparatus of the present invention, the strong acid aqueous solution is passed through by switching piping (channels) without replacing columns or the like.

That is, the production apparatus of the present invention includes acid supply piping (E _B-1 , E _B-2 ) that supplies a strong acid aqueous solution from a strong acid aqueous solution storage tank (B) to each ion exchange column (C ₁ , C ₂ ). ing. Note that this acid supply piping may also be two completely independent systems from the beginning, but as in the embodiment shown in FIG. 1, one piping extending from the strong acid aqueous solution storage tank (B) It is preferable to branch in the middle so as to connect to each ion exchange column.

By the way, a residual solution of the sodium hypochlorite aqueous solution is present in the ion exchange column (C ₁ ) to which the passage of the sodium hypochlorite aqueous solution has just been stopped. When the strong acid aqueous solution for regeneration is poured into the system, the inside of the system becomes strongly acidic, increasing the risk of chlorine gas generation.

Therefore, in order to wash the inside of the ion exchange column (C ₁ ) with water, the _production apparatus of the present invention has a water supply pipe ( _{EF- 1} ). In addition, in the illustrated embodiment of the water supply piping, one piping (E _F ) branches in the middle, and each piping (E _F-1 , E _F-2 ) is configured to go to each column. There is.

The water supply pipe (E _F-1 ) merges with the chemical solution supply pipe (E _A-1 ) and the acid supply pipe (E _B-1 ) in the middle, and connects the chemical solution supply pipe, the acid supply pipe, and the water supply pipe in one line. A pipe (E ₁ ) also serves as a supply pipe, and this is connected to the supply port of the ion exchange column (C ₁ ).

In addition to using only one pipe on the column outlet side as mentioned above, the device structure is improved by providing one route for liquid to flow into the ion exchange column and one route for discharging the liquid (one pipe). In addition to simplifying the process, the flow path of the liquid flowing into the column can always be kept constant. In addition, as shown in the figure, by providing the on-off valve (V _C-1 ) used for liquid level control downstream of the part where all these pipes join, there is no need to provide each pipe individually. can be simplified.

In the manufacturing apparatus of the present invention, the above-mentioned merging is performed by merging either the chemical solution supply pipe (E _A-1 ) or the acid supply pipe (E _B-1 ) with the water supply pipe (E _F-1 ), The remaining acid supply pipe (E _B-1 ) or chemical solution supply pipe (E _A-1 ) is arranged downstream of the merging part.

By merging each supply pipe in the above order, when water is flushed to wash the ion exchange column (C ₁ ), the inside of the pipe downstream from the merging part of the water supply pipe (E _F-1 ) is can also be washed with water at the same time, thereby reliably reducing the risk of chlorine gas generation. In other words, if the chemical solution supply pipe (E _A-1 ) and the acid supply pipe (E _B-1 ) join together first, the water supply pipe (E _F-1 ) upstream of the confluence part will be damaged even after washing with water. Because sodium hypochlorite aqueous solution (or strong acid aqueous solution) may remain in the pipes, there is a risk of chlorine gas being generated if the strong acid aqueous solution (or sodium hypochlorite aqueous solution) is flowed even after the pipes have been washed with water. However, by arranging the merging order in the above order, such a situation can be prevented from occurring.

In other words, the configuration of the supply piping in the manufacturing apparatus of the present invention as described above can minimize the risk of chlorine gas generation while simplifying the apparatus structure as much as possible.

Since the liquid coming out of the column outlet during the water washing becomes waste liquid, it is necessary to flow it into the waste liquid pipe (H) instead of flowing into the recovered liquid storage tank (D). Furthermore, from a safety perspective, the waste liquid should be divided into hypochlorous acid waste liquid (waste liquid from the water washing process before the column regeneration process described above) and acidic waste liquid (waste liquid from the column regeneration process and subsequent water wash process described below). It is preferable to have a piping configuration that allows these to flow separately so that they can be disposed of separately.

The piping (G/H ₁ ) connected to the outlet of the ion exchange column (C ₁ ) consists of two systems: an acid waste liquid piping (H _B-1 ) and a hypochlorite waste liquid piping (H _A-1 ). It branches into a waste liquid pipe (H ₁ ) and a treated chemical liquid transfer pipe (G ₁ ). In the embodiment shown in FIG. 1, the acid waste liquid pipe (H _B-1 ) is first branched from the pipe (G/H ₁ ) connected to the outlet of the ion exchange column (C ₁ ), and then the branch Downstream from the section, it branches into a treated chemical liquid transfer piping (G ₁ ) and a hypogastric waste liquid piping (H _A-1 ). By branching in this order, it is possible to reduce the possibility that the hypochlorous acid-based liquid and the acid-based liquid will mix in the piping when switching the flow paths, which is preferable from the viewpoint of safety. Further, each of these branched pipes is provided with an on-off valve so as to control the inflow of liquid into the pipe.

Note that these acid waste liquid pipes (H _B-1 ) and hyposubite waste liquid pipes (H _A-1 ) are also connected to waste liquid pipes (H _{B-2 ,} H _A-2 ) to form one acid waste liquid pipe (H _B ) and one hypochlorite waste liquid pipe (H _A ).

In addition, to prevent sodium hypochlorite aqueous solution and strong acid aqueous solution from being supplied to the same column or piping at the same time, or if such a situation is detected, such conditions can be stopped immediately. In some cases, it is also preferable to provide a safety mechanism for forcibly opening and closing each on-off valve (not shown).

Furthermore, in consideration of the case where chlorine gas is generated, it is preferable to provide a system pressure adjustment mechanism connected to a detoxification device (this is also not shown).

The procedure for regenerating the weakly acidic cation exchange resin in the production apparatus of the present invention having such a configuration will be briefly described. First, on the supply side to the column, as described above, after closing the on-off valve (V A- ₁ ) of the chemical solution supply pipe (E _A-1 ), the on-off valve (V F-1 ) of the water supply pipe (E _{F -1} ) is closed. ₁ ) is opened and water is allowed to flow to wash the inside of the supply pipe downstream of the confluence part and the inside of the ion exchange column (C ₁ ). At this time, on the discharge side, the on-off valves of the acid waste liquid piping (H _B-1 ) and the treated chemical liquid transfer piping (G ₁ ) are closed, and the liquid flowing out from the column outlet is transferred to the Hyposubium waste liquid piping (H _A-) . ₁ ).

After the water washing is completed, close the on-off valve (V _F-1 ) of the water supply pipe (E F _- 1), open the on-off valve (V _B-1 ) of the acid supply pipe (E _B-1 ), and perform ion exchange. A strong acid aqueous solution is passed through the column (C ₁ ) to regenerate the weakly acidic cation exchange resin. The discharged liquid at this time is made to flow as acidic waste liquid to the acidic waste liquid piping (H _B-1 ) side. That is, the on-off valve of the acid-based waste liquid piping is opened, and the on-off valve of the treated chemical liquid transfer piping (G ₁ ) and the on-off valve of the hypochlorite waste liquid piping (H _A-1 ) are closed.

The strong acid aqueous solution used here may be one that can regenerate (return to acid form) the weakly acidic cation exchange resin, and may be appropriately selected from known ones. It is common to use a solution diluted with water to about 1.0 mol/L.

A residual liquid of the strong acid aqueous solution used remains in the ion exchange column (C ₁ ) after completion of regeneration. Therefore, before passing the aqueous sodium hypochlorite solution, water is flowed through the water supply pipe (E _F-1 ) again to wash the inside. This waste liquid from washing is also flowed into the acid waste liquid piping (H _B-1 ) as an acid waste liquid.

The completion timing of the water washing and regeneration can be easily determined by, for example, monitoring the pH of the liquid discharged from the ion exchange column (C ₁ ) using the pH meter (J ₁ ).

Furthermore, by providing a metering pump in the common pipe (G/H ₁ ) before branching, it is possible to control the liquid volume with one pump at any stage from ion exchange treatment to regeneration.

The ion exchange column (C ₁ ) that has been subjected to the above regeneration operation can be used again to produce acidic hypochlorous acid water, and the second ion exchange column (C ₂ ) can be used to produce acidic hypochlorous acid water. After reaching this point, open and close each on-off valve to switch the flow path so that the sodium hypochlorite aqueous solution is passed through the first ion exchange column (C ₁ ) again to perform ion exchange treatment. good. On the second ion exchange column (C ₂ ) side, the weakly acidic cation exchange resin can be regenerated by the same method as described above.

Even while the sodium hypochlorite aqueous solution is being passed through the ion exchange column, there may be cases where it is not desirable to recover it as a product, such as if the pH of the solution discharged from the column is outside the desired range. obtain. Such a liquid may be flowed as a waste liquid to the hypochlorite waste liquid piping ( _HA ). For example, the pH may be quite low immediately after starting to pass the sodium hypochlorite aqueous solution, and one option is to discard such a solution.

In addition, each waste liquid from the hypochlorite waste liquid piping ( _HA ) and the acidic waste liquid piping (H _B ) may be directly connected to waste liquid treatment equipment and treated there, or once treated in a chemidrum, etc. The chemidrum, etc. may be stored in a facility with waste liquid treatment equipment. The waste liquid may be treated by appropriately selecting a known method.

Furthermore, in the illustrated embodiment, the water supply source for washing each ion exchange column with water and the water supply source for diluting the acidic hypochlorous acid water are the same, but different sources may be used as needed. You can prepare it. For example, it may be configured to use methods such as using ion-exchanged water for washing and using ultrapure water for dilution.

Since the production apparatus of the present invention passes a highly corrosive hypochlorous acid-based aqueous solution or a strong acid aqueous solution as described above, the contact surfaces of each storage tank, piping, on-off valve, column, and other members ( It is preferable that the inner surface) is made of resin, and in particular, a material with high durability against hypochlorous acid such as vinyl chloride, polypropylene, polyethylene, AS resin, ABS resin, PFA, and PTFE is preferable. Of course, in order to increase the strength, it may have an exterior made of FRP or metal. In particular, pipes made of resin can provide sufficient strength, but in order to obtain strength, each storage tank and column is preferably made of a structural material such as FRP, metal, or tempered glass, and coated with resin on the inner surface.

Further, the acidic hypochlorous acid water to be produced by the production apparatus of the present invention has better storage stability when metal (ions) are not mixed therein. In this respect as well, the inner surface of the manufacturing device is preferably made of resin. In normal use, the water supply piping (E _F-1 , E _F-2 ) upstream of the on-off valves (V _F-1 , V _F-2 ) is filled with sodium hypochlorite or a strong acid aqueous solution. Although these do not come into contact with each other, from the viewpoint of preventing the above-mentioned metal from being mixed in, it is preferable that the inner surface of this is also made of resin.

(summary)
As is clear from the above description, the acidic hypochlorous acid water production apparatus according to aspect 1 of the present invention,
a sodium hypochlorite aqueous solution storage tank (A);
A strong acid aqueous solution storage tank (B),
A plurality of (n) ion exchange columns (C ₁ to C _n ) filled with a weakly acidic cation exchange resin,
a recovered liquid storage tank (D) that stores the ion-exchanged chemical liquid;
Chemical solution supply piping (E _A-1 to E _A-n ) that supplies a chemical solution from the sodium hypochlorite aqueous solution storage tank (A) to each ion exchange column (C ₁ to C _n );
Acid supply piping (E B _-1 to E _B-n ) that supplies a strong acid aqueous solution from the strong acid aqueous solution storage tank (B) to each ion exchange column (C ₁ to C _n );
Water supply piping (E _F-1 to E F _-n ) that supplies water from the water supply source (F) to each ion exchange column (C ₁ to C _n ),
The chemical solution supply pipes (E _A-1 to E _A-n ), the acid supply pipes (E _B-1 to E _B-n ), and the water supply pipes (E _F-1 to E _F-n ) merge in the middle. As a result, there are n supply pipes (E ₁ to E _n ) each serving as a chemical solution supply pipe, an acid supply pipe, and a water supply pipe, and each of these supply pipes is connected to each ion exchange column (C ₁ to C _n ) is connected to the supply port of
And the said confluence is between either the chemical solution supply piping (E _A-1 to E _A-n ) or the acid supply piping (E _B-1 to E _B-n ) and the water supply piping (E _F-1 to E _F -n). _-n ), and the remaining acid supply pipes (E _B-1 to E _B-n ) or chemical solution supply pipes (E _A-1 to E _A-n ) join downstream of the merging point. It becomes,
Furthermore, each pipe (G/H ₁ to G/H _n ) is connected to the outlet of each ion exchange column (C ₁ to C _n ), and each pipe is connected to the recovered liquid storage tank (D). It is branched into treated chemical liquid transfer piping (G ₁ to G _n ) for transferring the ion-exchanged chemical liquid and waste liquid piping (H ₁ to H _n ) for transferring the liquid to be disposed of. and
The treated chemical liquid transfer pipes (G ₁ to G _n ) after the branching are merged to form a single processed chemical liquid transfer pipe (G), and the processed chemical liquid transfer pipe (G ) is characterized in that a water supply pipe (I) that supplies water from a water supply source (F) further merges with the water supply pipe (I).

In the acidic hypochlorous acid water production apparatus according to aspect 2 of the present invention, in the above-mentioned aspect 1, the waste liquid piping (H ₁ to H _n ) is an acidic waste liquid piping (H _B ) for transferring acidic waste liquid. _-1 to H _B-n ) and hypochlorous acid waste liquid piping (H _A-1 to H _A-n ) for transferring hypochlorous acid waste liquid.

The acidic hypochlorous acid water _production apparatus according to Aspect 3 of _the present invention is the same as Aspect 2 described above, in which each pipe (G/H ₁ ~ G/H _n ), acidic waste liquid piping (H _B-1 ~ H _B-n ) branches first, and then, downstream of the branch, treated chemical liquid transfer piping (G ₁ ~ G _n ) and the Hypochloreum waste liquid piping (H _A-1 to H _A-n ).

In the acidic hypochlorous acid water production apparatus according to aspect 4 of the present invention, in the above-mentioned aspect 2 or 3, each acid-based waste liquid piping (H _B-1 to H _B-n ) after the branching, and each It should be noted that the sub-system waste liquid pipes (H _A-1 to H _A-n ) are merged to form one acid-based waste liquid pipe (H _B ) and hypo-sub-system waste liquid pipe (H _A ). Features.

The acidic hypochlorous acid water production device according to Aspect 5 of the present invention is provided in any one of Aspects 1 to 4 described above, wherein the water supply source (F) is an ion exchange water storage tank, an ion exchange water production device, or It is characterized by being a pure water storage tank or an ultrapure water production device.

A method for producing acidic hypochlorous acid water according to aspect 6 of the present invention is characterized by using the acidic hypochlorous acid water production apparatus according to any one of aspects 1 to 5 described above.

(A): Sodium hypochlorite aqueous solution storage tank (B): Strong acid aqueous solution storage tank (C ₁ , C ₂ ): Ion exchange column (D): Recovery liquid storage tank (E _A , E _A-1 , E _{A -2} ): Chemical supply piping (E _B , E _B-1 , E _B-2 ): Acid supply piping (E _F , E _F-1 , E _F-2 ): Water supply piping (F): Water supply source (G/H ₁ , G/H ₂ ): Processed chemical liquid transfer pipe and waste liquid pipe (G, G ₁ , G ₂ ): Processed chemical liquid transfer pipe (H _B , H _B-1 , H _B-2 ): Acid waste liquid piping ( _HA , HA _-1 , HA _-2 ): Hypochloric waste liquid piping (J ₁ , J ₂ ): pH meter (K ₁ , K ₂ ): Level gauge (V _A-1) , V _A-2 , V _B-1 , V _B-2 , V _C-1 , V _C-2 , V _F-1 , V _F-2 ): Open/close valve

Claims (6)

a sodium hypochlorite aqueous solution storage tank (A);
A strong acid aqueous solution storage tank (B),
A plurality of (n) ion exchange columns (C ₁ to C _n ) filled with a weakly acidic cation exchange resin,
a recovered liquid storage tank (D) that stores the ion-exchanged chemical liquid;
Chemical solution supply piping (E _A-1 to E _A-n ) that supplies a chemical solution from the sodium hypochlorite aqueous solution storage tank (A) to each ion exchange column (C ₁ to C _n );
Acid supply piping (E B _-1 to E _B-n ) that supplies a strong acid aqueous solution from the strong acid aqueous solution storage tank (B) to each ion exchange column (C ₁ to C _n );
Water supply piping (E _F-1 to E F _-n ) that supplies water from the water supply source (F) to each ion exchange column (C ₁ to C _n ),
The chemical solution supply pipes (E _A-1 to E _A-n ), the acid supply pipes (E _B-1 to E _B-n ), and the water supply pipes (E _F-1 to E _F-n ) merge in the middle. As a result, there are n supply pipes (E ₁ to E _n ) each serving as a chemical solution supply pipe, an acid supply pipe, and a water supply pipe, and each of these supply pipes is connected to each ion exchange column (C ₁ to C _n ) is connected to the supply port of
And the said confluence is between either the chemical solution supply piping (E _A-1 to E _A-n ) or the acid supply piping (E _B-1 to E _B-n ) and the water supply piping (E _F-1 to E _F -n). _-n ), and the remaining acid supply pipes (E _B-1 to E _B-n ) or chemical solution supply pipes (E _A-1 to E _A-n ) join downstream of the merging point. It becomes,
Furthermore, each pipe (G/H ₁ to G/H _n ) is connected to the outlet of each ion exchange column (C ₁ to C _n ), and each pipe is connected to the recovered liquid storage tank (D). It is branched into treated chemical liquid transfer piping (G ₁ to G _n ) for transferring the ion-exchanged chemical liquid and waste liquid piping (H ₁ to H _n ) for transferring the liquid to be disposed of. and
The processed chemical liquid transfer pipes (G ₁ to G _n ) after the branching are merged to form a single processed chemical liquid transfer pipe (G), and the processed chemical liquid transfer pipe (G ) is further joined by a water supply pipe (I) that supplies water from a water supply source (F), an acidic hypochlorous acid water production apparatus. The waste liquid pipes (H ₁ to H _n ) are acid-based waste liquid pipes (H _B-1 to H _B-n ) for transferring acid-based waste liquid, and the following pipes for transferring hypochlorous acid-based waste liquid. The acidic hypochlorous acid water production apparatus according to claim 1, comprising two systems: sub-system waste liquid piping (H _A-1 to H _A-n ). From each pipe (G/H ₁ to G/H _n ) connected to the outlet of each ion exchange column (C ₁ to C _n ), first connect the acid waste liquid pipes (H _B-1 to H _B-n ) branches, and then, downstream of the branch, it branches into treated chemical liquid transfer piping (G ₁ to G _n ) and Hypogastric waste liquid piping (H _A-1 to H _A-n ). The acidic hypochlorous acid water manufacturing apparatus according to claim 2, wherein each pipe branches in this order. After the branching, each of the acid waste liquid pipes (H _B-1 to H _B-n ) and each of the Hypochloreum waste liquid pipes (H _A-1 to H _A-n ) are merged to form a single pipe. The acidic hypochlorous acid water production apparatus according to claim 2 or 3, comprising an acid waste liquid piping ( _HB ) and a hypochlorite waste liquid piping ( _HA ). Acidic hypochlorous acid water production according to any one of claims 1 to 3, wherein the water supply source (F) is an ion exchange water storage tank, an ion exchange water production device, an ultrapure water storage tank, or an ultrapure water production device. Device. A method for producing acidic hypochlorous acid water using the acidic hypochlorous acid water production apparatus according to any one of claims 1 to 3.

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