JPH1110164A - Disinfectant production method, method for disinfecting water, and apparatus therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aqueous chlorine dioxide solution immediately usable as a disinfectant in an optional concentration without specifically requiring a stirring apparatus. SOLUTION: While employing an apparatus comprising a horizontal pipe 2 having variable and quantitative flow rate valve 5 and in which an aqueous medium A is passed and an uprightly standing pipe 1 which is opened to the lower part of the horizontal pipe 2 and in which an aqueous hypochlorous acid solution D and an acid solution are introduced and reacted, an aqueous chlorine dioxide solution is produced by introducing a reaction liquid generated in the uprightly standing pipe 1 into the horizontal pipe 2 by gas lift of chlorine dioxide gas and dissolving the reaction liquid in the aqueous medium A. Moreover, by using water to be treated as the aqueous medium A, water to be treated is disinfected by circulating the water in the horizontal pipe 2 or a route including the horizontal pipe 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a disinfectant containing chlorine dioxide as an active ingredient, a method for disinfecting water, and an apparatus used for these.

[0002]

2. Description of the Related Art Sodium hypochlorite is well known as a disinfectant which is conventionally used for washing and bleaching vegetables, peaches, butterflies, grapes, cherries, eggs, etc. and is also useful for disinfecting pool water. Used. Above all, this is the mainstream disinfectant for purified water and pool water. In the pool water, besides, add highly bleached powder, fine powder such as trichloroisocyanuric acid, or a tableted product with a diameter of about 20 mm and a thickness of about 10 mm to reduce the residual chlorine concentration to 0.4 ppm as a legal standard. Adjusted to be used.
Also, sodium hypochlorite is widely used in food factories as a sterilizing detergent for vegetables and tableware. However, this sodium hypochlorite has a problem that trihalomethane, which is a carcinogen, is easily generated when used as a disinfectant of purified water in places where the water quality of the river intake is poor. In addition, children have swallowed tablets in pool water, and such hypochlorite fungicides have strong oxidizing power.
There are many cases of accidents, such as when the hair is bleached and reddened, and the need for improvement is called for. Further, when sodium hypochlorite is used as a cleaning agent for vegetables and the like, there is a problem that brown discoloration easily occurs.

[0003] Recently, in order to avoid the above-mentioned chemical damage, a bactericide based on chlorine dioxide, which has a lower oxidizing power than hypochlorite, is being used. For example, in the United States, Canada, Korea, Italy, Germany, and Northern Europe, chlorine dioxide sterilization has become the mainstream of water purification, and the trend has been worldwide. In addition, regarding the sterilization of pool water, the use of pools of general and public organizations was permitted in Japan in May 1993, and the residual chlorine dioxide concentration is specified as 0.4 ppm.

[0004]

At present, as a disinfectant containing chlorine dioxide as an active ingredient, a so-called stabilized chlorine dioxide is known. This chemical is produced by adding sodium percarbonate or hydrogen peroxide as a reducing agent to an aqueous sodium carbonate solution and absorbing chlorine dioxide gas (pH = 8.
5-9). In use, an acid is added as shown in the following formula to generate chlorine dioxide. 5NaClO ₂ + 4HCl = 4ClO ₂ + 5NaCl +
2H ₂ O Chlorine dioxide water thus activated by acid has a pH =
In about 4, chlorite ion (C
1O ₂ ⁻ ) and sodium chloride.
When the pH is adjusted to 2.5 or less by adding an acid, chlorite ions are completely converted to free chlorine dioxide, and a bactericidal effect can be obtained.

[0005] The use of aqueous sodium chlorite solution or stabilized chlorine dioxide as a commercial product is stable in alkaline conditions, but chlorite ions (ClO ₂₎ existing in the solution in this state are used. -) Is weak in bactericidal activity, and is therefore usually activated by acidification to produce free chlorine dioxide (a state in which chlorine dioxide is dissolved in water). At this time, since the residual amount of chlorite ion is set to WHO = 0.2 ppm or less in sterilization of purified water, it is necessary to completely convert chlorine dioxide to free chlorine dioxide. For sterilizing washing of vegetables and the like, it is supposed that ClO ₂ ⁻ does not remain in the processed food. Therefore, in order to sterilize with chlorine dioxide, a production method that does not leave chlorite ions is very important.

[0006]

Means for Solving the Problems The present inventors diligently studied means for solving the above problems and completed the present invention. According to the present invention, in dissolving chlorine dioxide in water to produce a disinfectant, a chlorite aqueous solution and an acid solution adjusted to a predetermined flow rate are separately injected into an upright tube, and are generated by a reaction between the two. A method for producing a disinfectant, which comprises introducing a liquid-gas mixture containing chlorine dioxide gas into a horizontal pipe attached to the top of an upright pipe by a gas lift and dissolving the chlorine dioxide gas in an aqueous medium flowing through the horizontal pipe. Provided. Further, according to the present invention, in performing water sterilization treatment with chlorine dioxide, a chlorite aqueous solution and an acid solution adjusted to a predetermined flow rate are separately injected into an upright pipe, and chlorine dioxide gas generated by a reaction between the two is injected. The liquid-gas mixture containing is introduced by a gas lift into a horizontal tube mounted on top of the upright tube,
A sterilization method for water is provided, wherein a sterilization treatment is performed by dissolving chlorine dioxide gas in water to be treated flowing through the horizontal pipe.

Further, according to the present invention, there is provided an apparatus for producing a disinfectant by dissolving chlorine dioxide in water or disinfecting water with chlorine dioxide, comprising an inlet and an outlet for an aqueous medium. And a vertical pipe opened at the lower part of the horizontal pipe and introducing a liquid-gas mixture containing chlorine dioxide gas, wherein a variable flow rate for adjusting the flow rate of the aqueous medium to be introduced is set in the horizontal pipe. A flow valve is provided, and a conduit for injecting a chlorite aqueous solution and an acid solution into the upright pipe by two pumps having a flow rate control device is provided below the upright pipe. An apparatus is provided, wherein a static mixer is provided in the flow path of the aqueous medium in the horizontal pipe downstream of the inlet of the liquid-gas mixture.

Further, according to the present invention, in performing the sterilization treatment of water with chlorine dioxide, an aqueous chlorite solution and an acid solution adjusted to a predetermined flow rate are separately introduced into an upright pipe, and are generated by a reaction between the two. A liquid-gas mixture containing chlorine dioxide gas is introduced by a gas lift into a horizontal pipe attached to the upper part of an upright pipe, and the chlorine dioxide gas is dissolved by dissolving the chlorine dioxide gas while circulating the water to be processed through a circulation path including the horizontal pipe. There is provided a method for disinfecting water characterized by performing disinfection of water, and a method for disinfecting water in which the water to be treated is pool water. Further, according to the present invention, there is provided an apparatus for disinfecting water by dissolving chlorine dioxide in water, comprising a storage tank, and a circulation path for circulating the water to be treated in the storage tank by a constant-quantity pump. A horizontal pipe forming a part of the path is provided with an upright pipe which is opened at a lower part of the horizontal pipe and introduces a liquid-gas mixture containing chlorine dioxide gas, and a lower part of the upright pipe has a flow control device. A sterilizer for water is provided, which is provided with conduits for injecting an aqueous solution of chlorite and an acid solution respectively into an upright pipe by two pumps, and a flow path of water to be treated in a circulation path. Has a static mixer provided downstream of the liquid-gas mixture inlet.

Further, according to the present invention, two pumps driven by one motor have respective pump heads, and after setting the injection ratio of the two solutions sent by each pump, A liquid pump is provided, comprising a device capable of controlling the flow rate of a solution.

The chlorite used in the present invention may be an alkali metal chlorite such as sodium chlorite, or an alkaline earth metal chlorite such as calcium chlorite or magnesium chlorite. And sodium chlorite is particularly preferred. The concentration of the aqueous chlorite solution is usually 5 to 25.
% By weight. Examples of the acid solution include various inorganic acids such as hydrochloric acid, sulfuric acid, and phosphoric acid, and various organic acids such as acetic acid, formic acid, citric acid, and malic acid. To activate the chlorite aqueous solution by adding an acid solution, it is necessary to adjust the pH to 2.5 to 5.0.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 illustrates an apparatus for producing a disinfectant by dissolving chlorine dioxide or disinfecting water with chlorine dioxide according to the present invention, and an upright pipe 1 for generating chlorine dioxide gas, and chlorine dioxide gas in an aqueous medium. It comprises a horizontal pipe 2 which dissolves to produce chlorine dioxide water. An aqueous medium is introduced from the inlet 3 into the horizontal pipe 2 in the direction of the arrow A, flows therethrough, dissolves the chlorine dioxide gas contained in the liquid-gas mixture rising in the upright pipe 1, and flows through the outlet 4 from the arrow 4. Discharge as chlorine dioxide water in the direction of B. A variable constant flow valve 5 for adjusting the flow rate of the flowing aqueous medium to a predetermined amount is provided in the horizontal pipe 2. Further, it is preferable to provide a static mixer 6 downstream of the mounting portion of the upright pipe 1 in order to efficiently mix the aqueous medium and the liquid-gas mixture introduced from the upright pipe. At this time, water can be sterilized in the horizontal pipe 2 by using the water to be treated as the aqueous medium.

[0012] conduits 7 and 8 underneath the standpipe 1 is attached, the acid solution in the direction of arrow C by the pump P ₁ is from the conduit 7, chlorite periodate in the direction of the arrow D by the pump P ₂ than the conduit 8 An aqueous solution is introduced. The two liquids react in the upright pipe 1 to generate chlorine dioxide gas, and a liquid-gas mixture containing this gas rises in the upright pipe by a gas lift action to produce a horizontal pipe 2.
Sent inside. The chlorite aqueous solution and the acid solution introduced into the upright pipe 1 are adjusted to a predetermined flow rate based on the above reaction formula, and can efficiently generate chlorine dioxide gas.
In order to perform such flow control, two pumps P ₁ and P ₂ having different pump heads are connected to one motor 9.
It is preferable to set in advance the injection ratio of the two solutions that are driven by the respective pumps, and to control the flow rates of the respective solutions by this. The use of a liquid pump having the above-described flow control device can simplify the device and operation, but another device capable of controlling the flow rate of each solution to a predetermined amount may be used. Since the flow rates of the chlorite aqueous solution and the acid solution are small, it is preferable to use a plunger pump for the pumps P ₁ and P ₂ .

The liquid-gas mixture in the upright pipe 1 rises due to the gas-lifting action of chlorine dioxide gas. This gas is generated by the reaction, and is a state in which fine bubbles are uniformly dispersed in the liquid phase. And the gas can be effectively stirred and mixed. Therefore, the liquid phase in the upright pipe is in a state where chlorine dioxide is dissolved according to the solubility,
Excess chlorine dioxide gas is completely dissolved in a large amount of aqueous medium flowing in the horizontal pipe 2, and uniform chlorine dioxide water is obtained.

The flow rate of the aqueous medium is adjusted by the variable constant flow rate valve 5, and the flow rates of the aqueous chlorite solution and the acid solution are adjusted by the above-mentioned flow rate control device. Can be produced.
This apparatus is useful for washing vegetables and fruits, for example, and the concentration of chlorine dioxide in an aqueous solution is usually 50 to 150.
It is preferable to adjust to about ppm. In addition, sterilization treatment can be performed using chlorine dioxide generated by circulating water to be treated such as purified water. The pH of the liquid is 2 to 3 in the upright pipe in order to generate sufficient chlorine dioxide gas. However, in the horizontal pipe, the pH is adjusted to about 4 to 6.5 by dilution with water.

FIG. 2 is a flow sheet showing another example of the water disinfection device according to the present invention.
Circulates the circulation path 12 by a metering pump _{P 3.} 13
The pump P ₁ and conduit 7 is acid solution horizontal pipe portion forming a part of the circulation path 12, it is injected into the standpipe 1 by chlorite solution and a pump P ₂ conduit 8, generated chlorine dioxide The liquid-gas mixture is introduced into the horizontal pipe 13 by the gas lift effect of the gas, as in FIG. It is preferable to provide a static mixer (not shown) in the flow path of the water to be treated in the horizontal pipe 13 as in FIG. The flow rate adjustment of the water to be treated can be carried out by metering pump P _3, the variable constant flow valve 5 as shown in FIG. 1 may not particularly provided. This apparatus is suitable for performing a sterilization treatment of pool water or the like as water to be treated, and sterilizes the storage tank 10 as a pool while circulating the pool water therein. Other aspects are the same as those in FIG. 1, but it is usually preferable to adjust the concentration of chlorine dioxide in the water to be treated to about 0.4 ppm.

[0016]

The present invention will be specifically described below with reference to examples and comparative examples. Example 1 A bactericide was produced using the apparatus shown in FIG. Horizontal pipe 2
500 liters / hour of tap water is passed through an inner diameter of 25 mm, a length of about 650 mm, an inner diameter of a static mixer insertion section of 40 mm, and PVC. a plunger pump _{P 1} and more hydrochloric acid (10.7 wt%) at a rate of 4.5m1 / min, a plunger pump from conduit 8 sodium chlorite aqueous solution (7 wt%) at a rate of 19.2 ml / min It was injected by P _2. The chlorine dioxide gas is generated by the reaction in the upright pipe, and the liquid-gas mixture rises in the upright pipe by the gas lift and is introduced into the horizontal pipe. Chlorine dioxide gas is completely dissolved in water and is discharged as chlorine dioxide water. Thus, free chlorine dioxide is reduced to about 100 pp.
A fungicide which can be used as washing water for vegetables containing m was continuously produced for 6 hours. Table 1 shows the results.

[0017] It is completely free of chlorine dioxide and chlorite ion is almost nonexistent.

COMPARATIVE EXAMPLE 1 An apparatus similar to that of Example 1, except that the conduit 7 is not connected to the upright pipe 1 but directly to the horizontal pipe 2 as shown in FIG. Introduced into tap water. Other than that, the operation was performed in exactly the same manner as in Example 1, and the results are shown in Table 2.

[0019] The reaction rate is poor and unstable, and a considerable amount of chlorite ion remains.

Example 2, Comparative Example 2 (Bactericidal Efficacy Test) Test of bactericidal efficacy of Escherichia coli, Staphylococcus aureus and S. typhimurium on fungicide A produced according to Example 1 and fungicide B produced according to Comparative Example 1. Was done. As a result, all the bacteria were completely killed by the fungicide A by the measurement after 10 minutes. Fungicide B was similar to fungicide A for Escherichia coli and Salmonella typhimurium, but it took 60 minutes to kill S. aureus. In addition, disinfectants A and B are diluted twice so that the concentration of free chlorine dioxide and the concentration of chlorite ion are 50 ppm.
In comparison with an aqueous sodium hypochlorite solution (concentration: 50 ppm, disinfectant C), it was found that each of the above bacteria was killed in 10 minutes after A, and in B only 60 minutes after only Staphylococcus aureus. Others were 10 minutes later, and C was 24 hours later for E. coli and Salmonella typhimurium.

From the above results, according to the present invention, an aqueous germicide solution containing almost 100% of free chlorine dioxide having a strong germicidal effect as an active ingredient can be produced at a stable reaction rate. Therefore, the standard of chlorite ion concentration WHO = 0.2 ppm or less required for sterilization of purified water can be easily satisfied. It can be seen that the bactericidal effect is far superior to the sodium hypochlorite aqueous solution, and also superior to the bactericide containing a large amount of chlorite ions.

[0022]

According to the method and apparatus of the present invention, a predetermined amount of chlorite aqueous solution and acid solution are reacted in an upright pipe,
A liquid-gas mixture containing free chlorine dioxide having a strong sterilizing power is generated in advance and is dissolved in a large amount of aqueous medium flowing in a horizontal pipe by a gas lift action. A usable chlorine dioxide water can be obtained. Since chlorine dioxide gas is generated at a low pH that does not leave chlorite ions in an upright pipe, it can be used not only for washing vegetables and fruits, but also for washing canteens, restaurants, kitchens, under the floor and under the floor. Useful. Water requiring sterilization as an aqueous medium,
For example, by circulating pool water, purified water, or the like, water can be directly sterilized efficiently in the apparatus. Since the operation can be performed at a stable concentration, the utilization rate of each drug is also improved. The device of the present invention has no particularly complicated structure and is easy to operate. Since it is a relatively small-sized device, it can be easily transported and installed at a place of use.

[Brief description of the drawings]

FIG. 1 is an explanatory view of an apparatus used for producing a disinfectant or disinfecting water according to the present invention.

FIG. 2 is a flow sheet showing another example of the water sterilizer according to the present invention.

[Description of Signs] 1 Upright pipe 2 Horizontal pipe 3 Inlet 4 Outlet 5 Variable constant flow valve 6 Static mixer 7 Pipe (acid solution) 8 Pipe (chlorite aqueous solution) 9 Motor 10 Storage tank 11 Treated water 12 Circulation route 13 horizontal pipe part P ₁ pump P ₂ pump P ₃ metering pump A water medium B chlorine dioxide water C acid solution D chlorite solution

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[Procedure amendment]

[Submission date] October 13, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction contents]

[0016]

The present invention will be specifically described below with reference to examples and comparative examples. Example 1 A bactericide was produced using the apparatus shown in FIG. Horizontal pipe 2
500 liters / hour of tap water is passed through an inner diameter of 25 mm, a length of about 650 mm, an inner diameter of a static mixer insertion section of 40 mm, and PVC. a plunger pump _{P 1} and more hydrochloric acid (10.7 wt%) in a ratio of 24.5 ml / min, plunger from conduit 8 sodium chlorite aqueous solution (7 wt%) at a rate of 19.2 ml / min It was injected by the pump _{P 2.} The chlorine dioxide gas is generated by the reaction in the upright pipe, and the liquid-gas mixture rises in the upright pipe by the gas lift and is introduced into the horizontal pipe. Chlorine dioxide gas is completely dissolved in water and is discharged as chlorine dioxide water. Approximately 100p of free chlorine dioxide
Continuous use of fungicides that can be used as washing water for vegetables containing pm 6
Time manufactured. Table 1 shows the results.

Continued on the front page (51) Int.Cl. ⁶ Identification code FI B01F 1/00 B01F 1/00 A

Claims (9)

[Claims] In producing a disinfectant by dissolving chlorine dioxide in water, an aqueous solution of chlorite and an acid solution adjusted to a predetermined flow rate are separately injected into an upright pipe, and the dioxide generated by the reaction of the two is injected. A method for producing a disinfectant, comprising introducing a liquid-gas mixture containing chlorine gas into a horizontal pipe attached to an upper part of an upright pipe by a gas lift, and dissolving chlorine dioxide gas in an aqueous medium flowing in the horizontal pipe. 2. In performing sterilization treatment of water with chlorine dioxide, a chlorite aqueous solution and an acid solution adjusted to predetermined flow rates are separately injected into an upright pipe, and contain chlorine dioxide gas generated by a reaction between the two. A method for sterilizing water, comprising introducing a liquid-gas mixture into a horizontal pipe attached to an upper part of an upright pipe by a gas lift, dissolving chlorine dioxide gas in water to be treated flowing through the horizontal pipe, and performing a sterilization treatment. . 3. An apparatus for producing a disinfectant by dissolving chlorine dioxide in water or disinfecting water with chlorine dioxide,
A horizontal pipe having an inlet and an outlet for the aqueous medium and through which the aqueous medium flows, and an upright pipe opened at the lower part of the horizontal pipe and introducing a liquid-gas mixture containing chlorine dioxide gas, Is provided with a variable constant flow valve for adjusting the flow rate of the aqueous medium to be introduced, and at the lower part of the upright pipe, an aqueous chlorite solution and an acid solution are respectively supplied to the upright pipe by two pumps having a flow rate control device. An apparatus, characterized in that a conduit for injection is provided. 4. The apparatus according to claim 3, wherein a static mixer is provided in the flow path of the aqueous medium in the horizontal pipe, downstream of the liquid-gas mixture inlet. 5. A process for disinfecting water with chlorine dioxide, in which a chlorite aqueous solution and an acid solution adjusted to a predetermined flow rate are separately introduced into an upright pipe, and contain chlorine dioxide gas generated by a reaction between the two. The liquid-gas mixture is introduced by a gas lift into a horizontal pipe attached to the upper part of the upright pipe, and the water to be processed is sterilized by dissolving the chlorine dioxide gas while circulating the water to be processed through a circulation path including the horizontal pipe. Disinfection method of water characterized by the above-mentioned. 6. The method for sterilizing water according to claim 5, wherein the water to be treated is pool water. 7. An apparatus for disinfecting water by dissolving chlorine dioxide in water, comprising: a storage tank; and a circulation path for circulating water to be treated in the storage tank by a metering pump. An upright pipe which is open at the lower part of the horizontal pipe and introduces a liquid-gas mixture containing chlorine dioxide gas is attached to a part of the horizontal pipe, and two pipes having a flow control device are provided at the lower part of the upright pipe. A sterilizing device for water, wherein conduits for injecting the chlorite aqueous solution and the acid solution into the upright pipe by the pump are provided. 8. The water sterilizer according to claim 7, wherein a static mixer is provided downstream of the liquid-gas mixture inlet in the flow path of the water to be treated in the circulation path. 9. Two pumps driven by one motor have respective pump heads, and after setting the injection ratio of two solutions sent by each pump, the flow rate of each solution can be controlled. A liquid pump comprising: