JP2001286871A - Manufacturing method of sterilizer and sterilizing method of water and device used therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such inconvenient problems that alkali chlorite and stabilized chlorine dioxide used for washing of vegetables and sterilization of pool water, are weak in effectivity under alkalinity, then acid needs to be added at the use site in order to activate them at acidity, and also free chlorine dioxide is difficult to produce at a stable concentration. SOLUTION: A device consisting of a horizontal pipe provided with a variable flow rate valve and through which a water medium passes, and a vertical pipe opened to the bottom of the horizontal pipe and introducing an aqueous chlorite solution and an acid solution to be allowed to react them in the pipe, is used for the following purpose. The reaction solutions are introduced into the horizontal pipe via a pressure valve or a check valve provided on the upper part of the vertical pipe by a gas lift of the chlorine dioxide generated in the vertical pipe, and are dissolved into the water medium to produce chlorine dioxide water. Also, by using water to be treated as the water medium, it is circulated in the horizontal pipe or in a path including the horizontal pipe to sterilize the water.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention 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 or calcium hypochlorite (bleached) is conventionally used as a bactericide for washing raw vegetables, eggs and the like, and also effective for disinfecting pool water. Powder) is well known. Particularly, in recent years, sodium hypochlorite has become the mainstream as a disinfectant for purified water and pool water. In the pool water, highly bleached powder, fine powder such as trichloroisocyanuric acid, or 20 mm in diameter,
Put in a tableted product with a thickness of about 10mm,
As a legal standard, it is used after adjusting the residual chlorine concentration to 0.4 mg / l. Also, sodium hypochlorite is widely used in food factories as a sterilizing detergent for vegetables and tableware. However, when this sodium hypochlorite is used as a disinfectant of purified water in places with poor water quality at the river intake, there is a problem that trihalomethane, which is a carcinogenic substance, is generated. Also, in pool water sterilization, conventional chlorination requires a large amount of energy for oxidative decomposition of organic substances, and as a result of the reaction, trihalomethane, which is specified in drinking water standards, is generated as a carcinogenic substance. The trihalomethane generated in the pool water volatilizes and drifts on the surface of the pool water, not only being carried to the organs of the swimmer and affecting them, but also endangers instructors and guards, and the obstacles spread. Has been reported.

[0003] Therefore, in order to avoid the above-mentioned chemical disorders, a bactericide based on chlorine dioxide, which has a lower oxidizing power than hypochlorite, has recently been used. For example, in the United States, Canada, Korea, Italy, Germany, and Northern Europe, chlorine dioxide sterilization is the mainstream in water purification, and the tendency is appearing strongly worldwide. Regarding the disinfection of swimming pools, in Japan, the use of "Public health and public bureau directors of the Ministry of Health and Welfare Bureau's hygiene standards for swimming pools" was approved on July 1, 1992 and used in pools of general and public institutions, and the chlorine dioxide concentration was 0.1 mg. / L or more and 0.4 mg / l or less, and the concentration of chlorite in water is specified as 1.2 mg / l or less.

[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, as shown in the following formula, for example, an acid is added similarly to sodium chlorite to generate chlorine dioxide. 5NaClO ₂ + 4HCl = 4ClO ₂ + 5NaCl +
2H ₂ O Chlorine dioxide water activated by the acid is pH
It is considered that mixing with no pressure at about = 4 contains chlorite ion (ClO ₂ ⁻ ) and sodium chloride in addition to free chlorine dioxide. Add acid and add pH
2.5 or less, or the reaction pressure is 0.5-5k
When the reaction is performed at g / cm ² , 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 gas is dissolved in water). At this time, since the residual amount of chlorite ions is set to be 0.2 mg / L or less for sterilization of purified water, it is necessary to completely convert the 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 inventor of the present invention has diligently studied means for solving the above-mentioned problems and filed a patent application (Japanese Patent Laid-Open No. 11-10164), but the present invention relates to the improvement thereof. . 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 liquid-gas mixture containing chlorine dioxide is introduced into the horizontal pipe by a gas lift through a pressure valve and / or a check valve attached to the upper part of the upright pipe. The present invention provides a method for producing a stable concentration of a bactericide, which comprises injecting and dissolving the reaction mixture. In disinfecting water 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 a liquid-gas mixture containing chlorine dioxide gas generated by a reaction between the two. Is introduced into the horizontal pipe through a pressure valve and / or a check valve attached to the upper part of the upright pipe by a gas lift, and chlorine dioxide gas and its reaction mixture are injected and dissolved at a constant concentration into the water to be treated flowing through the horizontal pipe. And a sterilization method for water, wherein the sterilization process is performed by water.

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 that opens at the bottom of the horizontal pipe and introduces a liquid-gas mixture containing chlorine dioxide gas through a pressure valve and / or a check valve. A variable constant flow rate valve for adjusting the flow rate of the medium is provided.
A device is provided, characterized in that a conduit is provided for injecting the aqueous chlorite solution and the acid solution into the upright pipe by means of a single pump. Further, this is 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-rate pump, and forming a part of the circulation path. The horizontal pipe is provided with an upright pipe which is opened at a lower portion of the horizontal pipe and introduces a liquid-gas mixture containing chlorine dioxide gas through a pressure valve and / or a check valve. A water disinfection device is provided, wherein conduits are provided for injecting a chlorite aqueous solution and an acid solution into an upright pipe by two pumps each having a flow control device. Note that a pressure valve is a valve from which liquid does not come out unless a constant pressure, for example, 1 kg / cm ² or more, is raised.

The chlorite used in the present invention is a chlorite of an alkali metal such as sodium chlorite, or a chlorite of an alkaline earth metal 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 and sulfuric acid, and various organic acids such as acetic 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.

[0009]

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, an upright pipe 1 for generating chlorine dioxide gas, and producing chlorine dioxide water. It consists of a horizontal tube 2. An aqueous medium is introduced into the horizontal pipe 2 from the inlet 3 in the direction of the arrow and flows therethrough, dissolves the chlorine dioxide gas contained in the liquid-gas mixture rising in the upright pipe 1, and flows from the outlet 4 to the arrow B In the direction of chlorine dioxide water. 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 that a static mixer 6 for efficiently mixing the aqueous medium and the liquid-gas mixture introduced from the upright pipe is provided downstream of the mounting portion of the upright pipe 1. At this time, water can be sterilized in the horizontal pipe 2 by using the water to be treated as the aqueous medium.

Pipes 7 and 8 are attached below the upright pipe 1, and the acid solution in the acid solution storage tank 9 is pumped from the pipe 7 by the pump P ₁ , and the chlorite aqueous solution tank is stored by the pump P ₂ from the pipe 8. A chlorite aqueous solution in 10 is introduced. The two liquids react in the upright pipe 2 to generate chlorine dioxide gas, and the liquid-gas mixture containing the gas rises in the upright pipe by a gas lift action and is sent into the horizontal pipe 2. 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 P having different pump heads are used.
₂ is driven by a single motor (not shown), it is preferable to set in advance the injection ratio of the two solutions for feeding by each pump, thereby controlling the flow rate of each solution. Further, since the flow rates of the aqueous chlorite solution and the acid solution are small, it is preferable to use a plunger pump or a pulse control pump as the pump P ₁ P ₂ .

Reference numeral 11 denotes a pressure valve and / or a check valve attached to the upper part of the upright pipe. The mixing rate of the chlorite aqueous solution and the acid solution is maintained by keeping the liquid-gas mixture flowing from the lower part at a constant pressure. Can be raised. By increasing the mixing ratio, the injection amount into the aqueous medium flowing through the horizontal pipe is stabilized, and the chlorine dioxide gas and its reaction mixture are pressed into the flowing aqueous medium to form finely divided chlorine dioxide gas. And the reaction mixture thereof can be easily mixed, and the concentration of chlorine dioxide can be stabilized.

The liquid-gas mixture in the upright pipe 1 is uniformly dispersed in the liquid phase by the gas lift of chlorine dioxide and the action of the pressure valve and / or the check valve as described above. It has been done. Accordingly, the liquid phase in the upright pipe is in a state in which chlorine dioxide gas is dissolved according to the solubility, and the 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 formed. can get.

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 example, for washing vegetables, fruits and the like, and the concentration of chlorine dioxide in an aqueous solution is usually 10 to 150.
It is preferable to adjust to about mg / l. In addition, sterilization treatment can be performed using chlorine dioxide generated by circulating water to be treated such as purified water. In addition, in the upright pipe, the pH of the liquid is 2 to 3.5 in order to generate sufficient chlorine dioxide gas.
However, in a horizontal tube, it is diluted with water and pH = 4 to
It is adjusted to about 6.5.

FIG. 2 is a flow sheet showing another example of the water disinfection device according to the present invention.
3 circulates the circulation path 14 by a metering pump _{P 3.} 1
5 by a pump P ₁ and conduit 7 is an acid solution a horizontal portion forming part of the circulation path 14, is injected into the standpipe 1 by chlorite solution and a pump P ₂ conduit 8, generated chlorine dioxide As in FIG. 1, the liquid-gas mixture is introduced into the horizontal pipe 15 via the pressure valve and / or the check valve 11 by the gas lifting action. It is preferable to provide a static mixer 6 in the flow path of the water to be treated in the horizontal pipe 15 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.
2 is used as a pool and sterilized while circulating the pool water therein. Other aspects are the same as those in FIG. 1, but usually the chlorine dioxide concentration in the water to be treated must be legally adjusted to 0.4 mg / l or less in the case of pool water.

[0015]

EXAMPLE 1 Using the apparatus shown in FIG. 1, the scale of an automatic control controller (not shown) was previously set to 30% in order to obtain 500 l / hr of 100 mg / l chlorine dioxide water. And an 8% by weight aqueous solution of sodium chlorite 955 ml / h
The pump P ₁ P ₂ was adjusted in advance so that the concentration of citric acid was 304 ml / hr at 50% by weight. 1 as the pressure valve 11
kg / cm ² was used. This automatic control controller has a scale displayed at 0 to 100%. When the scale is connected to the pump and the display is set to 100%, the rotation speed of the pump is maximized.
%, The output becomes minimum and the pump stops. With this controller, the flow rate of the pump was adjusted and the scale was changed to 10%, 20%, and 30% to prepare a calibration curve for the stability of the chlorine dioxide concentration (FIG. 3). The following data was obtained:

Comparative Example A calibration curve was prepared for the stability of chlorine dioxide concentration by the same method as in Example 1 except that the pressure valve was removed (FIG. 4), and the following data was obtained. Scale ClO ₂ mg / l (ppm) After 10 minutes After 40 minutes After 70 minutes 10% 42.3 30 25 20% 60.5 78 78 30% 120 110.6 104 The chlorine dioxide concentration has a very variable value. Indicated.

[0017]

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 bactericidal power is generated in advance, and this is dissolved in a large amount of aqueous medium flowing through the horizontal pipe by a gas lift action. A usable chlorine dioxide water can be obtained. Also, the passage of the liquid-gas mixture through the pressure valve and / or the check valve provided at the top of the upright pipe increases the mixing ratio, stabilizes the injection amount into the aqueous medium, and therefore dissolves the chlorine dioxide in the aqueous medium. It is possible to stabilize the concentration. 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. In addition, by distributing water that requires sterilization, for example, pool water, purified water, or the like as an aqueous medium, 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 does not have a 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.

FIG. 3 is a graph showing a calibration curve of Example 1.

FIG. 4 is a graph showing a calibration curve of a comparative example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Upright pipe 2 Horizontal pipe 3 Inlet 4 Outlet 5 Variable constant flow valve 6 Static mixer 7 Conduit (acid solution) 8 Conduit (chlorite aqueous solution) 9 Acid solution storage tank 10 Chlorite aqueous solution storage 11 Pressure valve and or the check valve 12 tank 13 the water to be treated 14 circulation path 15 horizontal pipe part P ₁ pump P ₂ pump P ₃ metering pump A water medium B chlorine dioxide water

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // C01B 11/02 C01B 11 / 02F

Claims (4)

[Claims] In dissolving chlorine dioxide in water to produce a bactericide, a chlorite aqueous solution and an acid solution adjusted to a predetermined flow rate are separately injected into an upright pipe, and the carbon dioxide generated by the reaction between the two is injected. A liquid-gas mixture containing chlorine is introduced by a gas lift into a horizontal pipe through a pressure valve and / or a check valve attached to the upper part of the upright pipe, and a chlorine dioxide gas and a chlorine dioxide gas having a constant concentration are introduced into an aqueous medium flowing through the horizontal pipe. A process for producing a stable concentration of a bactericide, which comprises injecting and dissolving a reaction mixture. 2. In sterilizing water 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 a solution containing chlorine dioxide gas generated by a reaction between the two. -The gas mixture is
It is introduced into the horizontal pipe through a pressure valve and / or a check valve attached to the upper part of the upright pipe, and chlorine dioxide gas and its reaction mixture are injected and dissolved at a constant concentration into the water to be treated flowing through the horizontal pipe to perform sterilization. A method of disinfecting water, which is performed. 3. A horizontal pipe for dissolving chlorine dioxide in water to produce a disinfectant or disinfecting water with chlorine dioxide, said horizontal pipe having an inlet and an outlet for an aqueous medium and flowing the aqueous medium. And an upright pipe that opens at the bottom of the horizontal pipe and introduces a liquid-gas mixture containing chlorine dioxide gas through a pressure valve and / or a check valve, and controls the flow rate of the aqueous medium to be introduced into the horizontal pipe. A variable constant flow valve is provided, and a conduit for injecting an aqueous chlorite solution and an acid solution into the upright pipe by two pumps each having a flow control device is provided below the upright pipe. Characteristic device. 4. 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. A horizontal pipe, which is open at a lower portion of the horizontal pipe, and through which a liquid-gas mixture containing chlorine dioxide gas is introduced through a pressure valve and / or a check valve, is attached to the horizontal pipe. Is provided with conduits for injecting a chlorite aqueous solution and an acid solution into an upright pipe by two pumps each having a flow control device.