JP2022023416A - Device of generating chlorine dioxide solution, and device of acidifying chlorite solution - Google Patents

Abstract

To provide a device of stably generating a chlorine dioxide solution of constant concentration for a long period of time.SOLUTION: The device of generating a chlorine dioxide solution by acidifying a chlorite solution to convert the acidified chlorite solution to a chlorine dioxide solution, comprises an intermittent quantitative pump 130 feeding the chlorite solution, a flow controller 110 allowing water for diluting the chlorite solution to flow at a constant flow rate, an ejector 120 for preparing a diluted chlorite solution of a uniform concentration by mixing the chlorite solution with water, acidifying means of acidifying the diluted chlorite solution, and a catalytic reactor 150 converting the diluted acidified chlorite solution acidified by the acidifying means to a chlorine dioxide solution.SELECTED DRAWING: Figure 1

Description

The present invention relates to a chlorine dioxide solution generator and a chlorite solution acidifier. More specifically, the present invention relates to a chlorine dioxide solution generator using a chlorite solution acidifier that acidifies a chlorite solution.

Chlorine dioxide solution is a substance having excellent oxidizing power and bactericidal power, and is widely used commercially as a bactericidal agent, a bleaching agent, and a fumigation disinfectant. The chlorine dioxide solution is highly volatile and is rapidly decomposed by light, so that it is difficult to store it. Therefore, when using a chlorine dioxide solution, it was necessary to generate it on-site each time it was used.

As a method for producing a chlorine dioxide solution, a method is known in which a chlorite solution is brought into contact with a cation exchange resin to acidify it, and an acidified chlorite solution is brought into contact with a catalyst to form a chlorine dioxide solution. (See Patent Document 1). In addition, as a device for generating chlorine dioxide-containing sterilizing water, the pH of the sodium chlorite solution is constantly measured in order to suppress variations in the concentration of the chlorine dioxide solution, and the pH is out of the control range. There is known a method of stabilizing the concentration of the chlorine dioxide solution by draining the liquid (see Patent Document 2).

Japanese Patent Publication No. 2004-5366761 JP-A-2015-217334

However, when the chlorine dioxide solution is produced by the method described in Patent Document 1, if the exchange capacity of the cation exchange resin is exceeded, the cation exchange resin must be regenerated, and the chlorine dioxide solution must be continuously regenerated. There was a problem that it could not be generated. Further, when the apparatus described in Patent Document 2 is used, the variation of the sodium chlorite concentration that can be detected by pH is large in consideration of the reproducibility of the pH meter and the measurement error, and the amount of change in the sodium chlorite concentration is at least. It was several hundred mg / L. Therefore, the effect of suppressing the variation in the concentration of the chlorine dioxide solution by pH control was insufficient.

The present invention has been made in view of the problems in the prior art, and provides a chlorine dioxide solution generating apparatus capable of stably producing a chlorine dioxide solution having a constant concentration for a long period of time.

In order to achieve the above object, the present invention comprises at least the following configurations or carries out procedures.

The chlorine dioxide solution generator according to one aspect of the present invention is a chlorine dioxide solution generator that acidifies a chlorite solution and converts the acidified chlorite solution into a chlorine dioxide solution. An intermittent metering pump that feeds the chlorite solution, a flow controller for circulating a constant amount of water for diluting the chlorite solution, the chlorite solution, and the water are mixed. The ejector for obtaining a chlorite diluted solution having a uniform concentration, the acidifying means for acidifying the chlorite diluted solution, and the chlorite diluted solution acidified by the acidifying means are distilled off. It is characterized by having a catalytic reactor that converts to a chlorine solution.
With such a configuration, a chlorine dioxide solution having a constant concentration can be stably produced for a long period of time. This is because the chlorite solution and water can be more reliably mixed by combining the intermittent metering pump and the ejector.

Further, preferably, the ejector has at least one suction portion, and the suction portion and the intermittent metering pump are connected to each other.
With such a configuration, water and the chlorite solution can be mixed more reliably.

Further, preferably, the flow rate controller is characterized by being a constant flow rate valve.
With such a configuration, the flow rate can be kept constant more reliably. The constant flow rate valve is a flow rate control valve that does not require an electrical driving force, and has a mechanism that keeps the flow rate constant by the internal valve mechanism even when pressure changes on the temporary side and secondary side occur. ing.

Further, preferably, the intermittent metering pump for feeding the chlorite solution is a diaphragm type pump.
With such a configuration, water and the chlorite solution can be mixed more reliably.

Further, it is preferably characterized in that the amount of the chlorine dioxide solution produced is 0.001 to 1 L / min.

Further, it is preferably characterized in that the concentration of the chlorite solution is 1 to 10000 mg / L as the chlorite ion concentration.

Further, preferably, the catalyst reactor is characterized by comprising a platinum alumina catalyst in which 0.01 to 0.25% by mass of platinum is supported on an activated alumina carrier.
With such a configuration, the production yield of chlorine dioxide can be further improved.

Further, preferably, the activated alumina carrier is characterized by having a specific surface area value of 50 to 300 m ² / g and a particle size of 0.1 to 10 mm.
With such a configuration, the acidified chlorite diluted solution can be reacted with the catalyst more stably.

The chlorite solution acidifying device according to one aspect of the present invention is a chlorite solution acidifying device that acidifies a chlorite solution, and is an intermittent quantification that feeds the chlorite solution. A pump, a flow controller for circulating a constant amount of water for diluting the chlorite solution, the chlorite solution, and the water are mixed to have a uniform concentration of chlorite. It is characterized by having an ejector for obtaining a diluted solution and an acidifying means for acidifying the chlorite diluted solution.
With such a configuration, an acidified chlorite solution having a constant concentration can be stably produced. This is because the chlorite solution and water can be more reliably mixed by combining the intermittent metering pump and the ejector.

As described above, according to the present invention, a chlorine dioxide solution having a constant concentration can be stably produced for a long period of time.

It is a figure which shows the chlorine dioxide solution generation apparatus 100 which concerns on 1st Embodiment of this invention. It is a figure which shows the chlorine dioxide solution generation apparatus 200 which concerns on 2nd Embodiment of this invention. It is a figure which shows the chlorine dioxide solution generation apparatus 300 which concerns on 3rd Embodiment of this invention. It is a figure which shows the chlorine dioxide solution generation apparatus 400 which concerns on 4th Embodiment of this invention. It is a figure which shows the chlorite solution acidifying apparatus 500 which concerns on 5th Embodiment of this invention. It is a figure which shows the chlorite solution acidifying apparatus 600 which concerns on 6th Embodiment of this invention. It is a figure which shows the chlorite solution acidifying apparatus 700 which concerns on 7th Embodiment of this invention. It is a figure which shows the chlorite solution acidifying apparatus 800 which concerns on 8th Embodiment of this invention. It is a figure which shows the transition of the chlorine dioxide concentration, the chlorous acid concentration, and the chlorine dioxide production amount which concerns on Example 1 of this invention.

Hereinafter, the chlorine dioxide solution generator 100 according to the first embodiment of the present invention will be specifically described with reference to the drawings. It should be noted that the embodiments described below are merely specific examples for carrying out the present invention, and do not limit the interpretation of the present invention.

FIG. 1 is a diagram showing a chlorine dioxide solution generator 100 according to the first embodiment of the present invention. As shown in FIG. 1, the chlorine dioxide solution generator 100 includes a flow rate controller 110, an ejector 120, an intermittent metering pump 130, a three-chamber electrolytic cell 140, and a catalyst reactor 150. It also has a solenoid valve 160, a needle valve 170, and a water softener 180. The solenoid valve 160, needle valve 170, and water softener 180 can be omitted as appropriate. Further, the three-chamber type electrolytic cell 140 has an anode chamber 142 having an anode 141, a cathode chamber 144 having a cathode 143, and an ion exchange chamber 145 located between the anode chamber 142 and the cathode chamber 144. The anode chamber 142, the cathode chamber 144, and the ion exchange chamber 145 are partitioned by a cation exchange membrane 146.

A feature of the present invention is that the intermittent metering pump 130 and the ejector 120 are combined. By using the intermittent metering pump 130 and the ejector 120, it is possible to uniformly mix the chlorite solution and water even in a small flow rate range. In the small flow rate region, it is not possible to uniformly mix with either the intermittent metering pump 130 or the ejector 120, so that a chlorine dioxide solution having a constant concentration cannot be stably produced for a long period of time.

A method for generating a chlorine dioxide solution by using the chlorine dioxide solution generating device 100 according to the first embodiment of the present invention described above will be specifically described. The water supplied from the water softener 180 passes through the solenoid valve 160 and the needle valve 170, and is sent to the anode chamber 142 and the cathode chamber 144 of the three-chamber type electrolytic cell 140. Further, the water passes through the flow rate controller 110 and is sent to the ejector 120 at a constant flow rate. A chlorite solution (a sodium chlorite solution is described as an example) is injected from the suction portion side of the ejector 120 by an intermittent metering pump 130, and the chlorite solution and water are mixed inside the ejector 120. Is uniformly mixed to form a chlorite diluent.

The chlorite diluted solution is sent to the ion exchange chamber 145 from the inlet side of the three-chamber type electrolytic cell 140. When the water and the chlorite diluted solution are sent, the electrolysis of water shown below occurs at the anode 141 and the cathode 143 by applying a voltage.
Anode: 2H ₂ O → 4H ⁺ + ^4e- + O ₂
Cathode: 4H ₂ O + ^4e- → ^4OH- + 2H ₂

The hydrogen ions generated at the anode 141 pass through the cation exchange membrane 146 and move from the anode chamber 142 to the ion exchange chamber 145. In the sodium chlorite solution supplied to the ion exchange chamber 145, a part or all of the sodium ions are replaced with hydrogen ions here to become an acidified chlorite diluted solution. That is, the electrolysis in the three-chamber electrolytic cell 140 is an acidifying means for acidifying the chlorite diluted solution.
NaClO ₂ + H ⁺ → HClO ₂ + Na ⁺

The acidifying means for acidifying the chlorite diluted solution is not limited to the method using the three-chamber electrolytic cell 140, but also the method of contacting with a cation exchange resin and the diaphragm type electrolysis separated by a cation exchange film. A method using a tank, a method of adding an acidic substance to the zinc salt, or the like may be used.

Sodium ions move from the ion exchange chamber 145 to the cathode chamber 144 through the cation exchange membrane 146, and then combine with the hydroxyl group generated in the cathode 143 to become sodium hydroxide.

When the ion exchange chamber 145 is filled with a cation exchange resin or the like, it is preferable because it improves the replacement efficiency of metal ions and hydrogen ions in the chlorite solution and also contributes to the improvement of conductivity.

The acidified chlorite diluted solution discharged from the outlet side of the ion exchange chamber 145 is then supplied to the catalyst reactor 150 and converted into a chlorine dioxide solution by contact with the catalyst in the catalyst reactor 150. It is considered that the production of chlorine dioxide by the catalytic reaction proceeds according to the following equation.

Since the acidified chlorite diluted solution gradually decomposes and produces by-products such as chlorate, it is desirable to contact and react with the catalyst as soon as possible. The time from the acidification treatment of the chlorite solution to the contact / reaction with the catalyst is preferably within 30 minutes, more preferably within 10 minutes.

The flow rate controller 110 used in the chlorine dioxide solution generator 100 according to the first embodiment of the present invention uses a constant flow rate valve. The constant flow rate valve is a flow rate control valve that does not require an electric driving force, and has a mechanism for keeping the flow rate constant by an internal valve mechanism even when pressure changes on the primary side and the secondary side occur. A proportional control valve may be used for the flow rate controller 110. The proportional control valve is a device that can control the flow rate by adjusting the opening degree of the valve based on the signal from the flow meter.

The ejector 120 used in the chlorine dioxide solution generator 100 according to the first embodiment of the present invention reduces the pressure in the space around the nozzle by injecting the main fluid from the nozzle at a high pressure (Venturi effect), and the external first. 2 A device that sucks fluid. The ejector 120 is widely used for transporting fluids, diluting / mixing applications, and the like. In the present invention, the main fluid is water and the external second fluid is a chlorite solution. The chlorite solution is sucked from the suction portion of the ejector 120.

The ejector 120 has a venturi effect and can be used without particular limitation as long as it is a device provided with one or more suction portions for sucking the second fluid. For example, various ejectors 120 commonly used in the industrial field and the industrial field can be used. The nozzle diameter of the ejector 120 used in the present invention is not particularly limited, but when the amount of chlorine dioxide produced is 1 L / min or less, the inner diameter is preferably φ3 mm or less.

Normally, when the second fluid is sucked by the ejector 120, it is necessary to circulate the main fluid at a high flow rate. For example, in a small flow rate range of 1 L / min or less, the suction / mixing effect of the fluid is hardly obtained. .. In the present invention, the suction unit that sucks the second fluid of the ejector 120 and the intermittent metering pump 130 are connected with the second fluid so that the fluid mixing effect can be obtained even in a small flow rate range of 1 L / min or less. A chlorite solution is injected into the ejector 120 by an intermittent metering pump 130. As a result, water, which is the main fluid, and the chlorite solution, which is the second fluid, are mixed at a uniform concentration.

Examples of the intermittent metering pump 130 used in the present invention include a diaphragm type pump, a plunger type pump, a piston type pump, and the like, and a diaphragm type pump is particularly preferable. The discharge performance of the diaphragm pump is appropriately selected according to the concentration of the chlorite solution used and the amount of chlorine dioxide produced.

As the electrode of the three-chamber type electrolytic cell 140 used in the present invention, a platinum coating material in which platinum is plated on a titanium base material is used for the anode 141 and the cathode 143, but the present invention is not limited thereto. For example, graphite, graphite felt, multilayer graphite cloth, graphite woven cloth, carbon or the like may be used as the material of the anode 141. Further, as the material of the cathode 143, titanium, stainless steel, nickel, nickel-chromium alloy or the like may be used. By using a platinum-coated material in which platinum is plated on a titanium base material for the anode 141 and the cathode 143, the electrolysis efficiency and durability can be improved.

As the shape of the electrode, it is preferable to use an expanded metal, a punching metal, a net, or the like having a large specific surface area. However, electrodes having other shapes may be used.

As the cation exchange membrane 146, a fluorine-based cation exchange membrane having excellent oxidation resistance is used. For example, NAFION (registered trademark) 112, 115, 117 of The Chemours Company, Flemion (registered trademark) of Asahi Glass Co., Ltd., ACIPLEX (registered trademark) of Asahi Kasei Corporation, and the like can be used.

When a cation exchange resin is used in the ion exchange chamber 145, it is preferable to use a strongly acidic cation exchange resin of a styrene-divinylbenzene copolymer. The degree of cross-linking is preferably 10 or more, and more preferably 16 or more. Not limited to this, a weakly acidic cation exchange resin of a styrene-divinylbenzene copolymer may be used.

As a commercially available cation exchange resin, for example, Mitsubishi Chemical Corporation's Diaion SK110, SK116, PK220, and PK228 can be used.

In the present invention, water is circulated through the anode chamber 142 and the cathode chamber 144, but an electrolyte solution may be circulated for the purpose of increasing conductivity. Examples of the electrolyte solution used for the anode chamber 142 include an inorganic acid solution and an organic acid solution, of which a sulfuric acid solution and a hydrochloric acid solution are preferable. As the electrolyte solution used in the cathode chamber 144, a caustic alkaline solution is preferable, and a sodium hydroxide solution and a potassium hydroxide solution are particularly preferable. Since caustic alkali is generated in the cathode chamber 144 during the electrolysis process, the electrolyte solution may be circulated only at the start of electrolysis. Instead of circulating the electrolyte solution, the anode chamber 142 and the cathode chamber 144 may be filled with a cation exchange resin and water may be circulated.

As the chlorite solution used in the chlorine dioxide solution generator 100 according to the first embodiment of the present invention, sodium chlorite is used as an example, but an alkali metal salt of chlorous acid or alkaline soil is used. Chlorite salts may be used. Examples of the alkali metal chlorite salt include sodium chlorite, potassium chlorite, and lithium chlorite. Examples of the alkaline earth metal salt include calcium chlorite, magnesium chlorate, and barium chlorate. As the form of chlorite, an alkali metal salt such as a sodium salt or a potassium salt is preferable from the viewpoint of water solubility and economic efficiency. note that. The above-mentioned chlorite may be used alone or in combination of two or more.

The concentration of the chlorite solution supplied from the inlet side of the ion exchange chamber 145 is preferably 1 to 10000 mg / L, more preferably 100 to 7000 mg / L, and particularly preferably 500 to 5000 mg / L as chlorite ions. At 10,000 mg / L or more, the pH of the acidified chlorite diluted solution becomes too low, so that the decomposition reaction of chlorite ions proceeds before contact with the catalyst, and the yield of chlorine dioxide decreases. May reduce catalyst life. Further, at 1 mg / L or less, a sufficient amount of chlorine dioxide cannot be produced.

Further, the chlorite solution may contain other components. Examples of other components include inorganic acids such as hydrochloric acid, sulfuric acid, phosphoric acid, boric acid and nitrate and salts thereof, organic acids such as citric acid, malic acid, lactic acid, acetic acid, formic acid and methanesulfonic acid and salts thereof. Examples thereof include chelating agents such as polyacrylic acid-based polymers and salts thereof, 1-hydroxyethane-1,1-diphosphonic acid and salts thereof, and tripolyphosphate and salts thereof.

The pH value of the acidified chlorite solution is preferably 1.0 to 3.0, more preferably 1.5 to 2.5. If the pH value is lower than 1.0, the life of the catalyst may be shortened, and if the pH value is higher than 3.0, the yield of chlorine dioxide may decrease.

As the water supplied from the water softener 180, for example, tap water, RO water, ion-exchanged water, or soft water can be used. In addition, water may be supplied by connecting a faucet and a hose without using the water softener 180.

The catalytic reactor 150 is used for the purpose of oxidizing the acidified chlorite diluent to produce chlorine dioxide. As the catalyst used in the catalyst reactor, a platinum alumina catalyst (Pt / Al _{2O 3} ) in which platinum is supported on an activated alumina carrier is used. The platinum on the activated alumina carrier may be either a platinum atom or a platinum oxide, but a mixture thereof is more preferable. As the platinum oxide, platinum oxidation numbers +2 and +4 are preferable.

The amount of platinum supported is preferably 0.01 to 0.50% by mass, more preferably 0.01 to 0.25% by mass. If the carrying amount is less than 0.01% by mass, the chlorine dioxide production rate is slow, and if it is higher than 0.25% by mass, the amount of by-products produced increases and the chlorine dioxide yield decreases.

The properties of the activated alumina carrier used for the catalyst preferably have a specific surface area value of 50 to 300 m ² / g. The particle size is preferably 0.1 to 10 mm, more preferably 0.3 to 7 mm.

The activated alumina carrier may be a powder, but is preferably a molded carrier. If it is a molded carrier, the catalyst can be used as a fixed bed, a product can be obtained by circulating the reaction product under predetermined conditions, and there is no need to separate the catalyst from the product, which is an industrially advantageous catalyst. It can be said that. The shape of such a molded carrier is preferably a spherical carrier, but it may be in the shape of a pellet, a shape of a honeycomb, or the like depending on the intended use.

Among the above-mentioned molded carriers, those having voids inside are preferable. Platinum is supported on the surface of the carrier that forms voids by catalyzing such a molded carrier. On the other hand, the reacting substrate enters the voids of this catalyzed carrier and reacts to produce a reactant. Such voids are represented as pore volume. When such a molded carrier is used in the present invention, its pore volume is preferably 0.3 to 0.7 mL / g.

The activated alumina carrier used for the catalyst may contain other components that can be generally used as a carrier for the catalyst, such as titania and silica.

Other catalyst components and co-catalyst components may be added to the catalyst. Examples of other catalyst components include metals such as palladium and rhodium, and examples of co-catalyst components include transition metals such as gold, copper, iron, bismuth, vanadium, and chromium.

The catalyst can be prepared by impregnating or spraying an alumina carrier in a solution containing a platinum precursor, drying and calcining the catalyst.

Platinum precursors carried on the active alumina carrier include platinum chloride, sodium chloride, potassium chloride, ammonium chloride, hexahydrooxoplatinic acid, dinitrodiammine platinum nitrate, hexaammine platinum chloride, hexaammine platinum. At least one selected from hydroxide, hexaammine platinum nitrate, tetraammine platinum chloride, tetraammine platinum hydroxide, tetraammine platinum nitrate, platinum black, hexahydroxoplatinate ethanolammonium, platinum acetylacetonate can be used. ..

Platinum may be unevenly distributed and supported on the outer shell side of the activated alumina carrier on the activated alumina carrier. A catalyst in which platinum is unevenly supported on the surface side of an activated alumina carrier can effectively utilize the active species in the catalyst by concentrating the active species on the catalyst surface where the reaction is most promoted in the catalytic reaction. , Platinum and other expensive precious metals can be used efficiently.

As the catalyst, a commercially available platinum alumina catalyst may be used, and examples of such a catalyst include NM-103 of N.E. Chemcat and MFCD0001179 of Alfa Aesar.

Next, the chlorine dioxide solution generator 200 according to the second embodiment of the present invention will be described with reference to FIG. FIG. 2 is designated by the same reference numeral, and detailed description thereof will be omitted. In this embodiment, a configuration different from the first embodiment of the present invention will be mainly described.

The chlorine dioxide solution generator 200 according to the second embodiment of the present invention includes a flow rate controller 110, an ejector 120, an intermittent metering pump 130, a three-chamber electrolytic cell 140, and a catalyst reactor 150. It also has a solenoid valve 160, a needle valve 170, a water softener 180, and a flow meter 190. The solenoid valve 160, needle valve 170, water softener 180, and flow meter 190 can be omitted as appropriate. Further, in the chlorine dioxide solution generator 200, a proportional control valve is used as the flow rate controller 110. When a proportional control valve is used, it is preferable to provide a flow meter 190 between the water softener 180 and the ejector 120.

Next, the chlorine dioxide solution generator 300 according to the third embodiment of the present invention will be described with reference to FIG. FIG. 3 is designated by the same reference numeral, and detailed description thereof will be omitted. In this embodiment, a configuration different from the first embodiment of the present invention will be mainly described.

The chlorine dioxide solution generator 300 according to the third embodiment of the present invention includes a flow rate controller 110, an ejector 120, an intermittent metering pump 130, a cation exchange resin tower 147, and a catalyst reactor 150. .. It also has a solenoid valve 160. The solenoid valve 160 can be omitted as appropriate. Further, the chlorine dioxide solution generation device 300 employs a method using a cation exchange resin tower 147 filled with a cation exchange resin as an acidifying means for acidifying the chlorite diluted solution. The chlorite diluted solution sent from the ejector 120 is acidified by passing through the cation exchange resin tower 147, and a chlorine dioxide solution is produced in the catalytic reactor 150.

Next, the chlorine dioxide solution generator 400 according to the fourth embodiment of the present invention will be described with reference to FIG. FIG. 4 is designated by the same reference numeral, and detailed description thereof will be omitted. In this embodiment, a configuration different from the first embodiment of the present invention will be mainly described.

The chlorine dioxide solution generator 400 according to the fourth embodiment of the present invention includes a flow rate controller 110, an ejector 120, an intermittent metering pump 130, and a catalytic reactor 150. It also has a solenoid valve 160. The solenoid valve 160 can be omitted as appropriate. In the chlorine dioxide solution generator 400, a hydrochloric acid solution, which is an acidic solution, is added to the ejector 120 as an acidifying means for acidifying the chlorite diluted solution. Specifically, water is circulated to the ejector 120 by the flow rate controller 110, and the chlorite solution and the hydrochloric acid solution are injected into the suction portion of the ejector 120. The ejector 120 has two suction portions, and a chlorite solution and a hydrochloric acid solution are injected into different suction portions. Further, in the chlorine dioxide solution generator 400, a diaphragm type pump is used for the intermittent metering pump 130.

<Chlorite solution acidifier>
Although the chlorine dioxide solution generator has been described so far, when the catalyst reactor 150 is removed from the chlorine dioxide solution generator described above, it can be used as a chlorite solution acidifier. The acidified chlorite solution can be used as a cleaning solution for foods such as vegetables. Hereinafter, the chlorite solution acidifying device will be described.

FIG. 5 describes the chlorite solution acidifying device 500 according to the fifth embodiment of the present invention. FIG. 5 is designated by the same reference numeral, and detailed description thereof will be omitted.

FIG. 5 is a diagram showing a chlorite solution acidifying device 500 according to a fifth embodiment of the present invention. As shown in FIG. 5, the chlorite solution acidifying device 500 includes a flow rate controller 110, an ejector 120, an intermittent metering pump 130, and a three-chamber electrolytic cell 140. It also has a solenoid valve 160, a needle valve 170, and a water softener 180. The solenoid valve 160, needle valve 170, and water softener 180 can be omitted as appropriate. Further, the three-chamber type electrolytic cell 140 has an anode chamber 142 having an anode 141, a cathode chamber 144 having a cathode 143, and an ion exchange chamber 145 located between the anode chamber 142 and the cathode chamber 144. The anode chamber 142, the cathode chamber 144, and the ion exchange chamber 145 are partitioned by a cation exchange membrane 146.

A method for producing an acidified chlorite solution using the chlorite solution acidifying device 500 according to the fifth embodiment of the present invention described above will be specifically described. The water supplied from the water softener 180 passes through the solenoid valve 160 and the needle valve 170, and is sent to the anode chamber 142 and the cathode chamber 144 of the three-chamber type electrolytic cell 140. Further, the water passes through the flow rate controller 110 and is sent to the ejector 120 at a constant flow rate. A chlorite solution (a sodium chlorite solution is described as an example) is injected from the suction portion side of the ejector 120 by an intermittent metering pump 130, and the chlorite solution and water are mixed inside the ejector 120. Is uniformly mixed to form a chlorite diluent.

The chlorite diluted solution is sent to the ion exchange chamber 145 from the inlet side of the three-chamber type electrolytic cell 140. When the water and the chlorite diluted solution are sent, the electrolysis of water shown below occurs at the anode 141 and the cathode 143 by applying a voltage.
Anode: 2H ₂ O → 4H ⁺ + ^4e- + O ₂
Cathode: 4H ₂ O + ^4e- → ^4OH- + 2H ₂

The hydrogen ions generated at the anode 141 pass through the cation exchange membrane 146 and move from the anode chamber 142 to the ion exchange chamber 145. In the sodium chlorite solution supplied to the ion exchange chamber 145, a part or all of the sodium ions are replaced with hydrogen ions here to become an acidified chlorite solution. That is, the electrolysis in the three-chamber electrolytic cell 140 is an acidifying means for acidifying the chlorite diluted solution.
NaClO ₂ + H ⁺ → HClO ₂ + Na ⁺

Next, the chlorite solution acidifying apparatus 600 according to the sixth embodiment of the present invention will be described with reference to FIG. FIG. 6 is designated by the same reference numeral, and detailed description thereof will be omitted. In this embodiment, a configuration different from the fifth embodiment of the present invention will be mainly described.

The chlorite solution acidifying device 600 according to the sixth embodiment of the present invention includes a flow rate controller 110, an ejector 120, an intermittent metering pump 130, and a three-chamber electrolytic cell 140. It also has a solenoid valve 160, a needle valve 170, a water softener 180, and a flow meter 190. The solenoid valve 160, needle valve 170, water softener 180, and flow meter 190 can be omitted as appropriate. Further, in the chlorite solution acidifying device 600, a proportional control valve is used as the flow rate controller 110. When a proportional control valve is used, it is preferable to provide a flow meter 190 between the water softener 180 and the ejector 120.

Next, the chlorite solution acidifying apparatus 700 according to the seventh embodiment of the present invention will be described with reference to FIG. 7. FIG. 7 is designated by the same reference numeral, and detailed description thereof will be omitted. In this embodiment, a configuration different from the fifth embodiment of the present invention will be mainly described.

The chlorite solution acidifying device 700 according to the seventh embodiment of the present invention includes a flow rate controller 110, an ejector 120, an intermittent metering pump 130, and a cation exchange resin tower 147. It also has a solenoid valve 160. The solenoid valve 160 can be omitted as appropriate. Further, in the chlorite solution acidifying device 700, a method using a cation exchange resin tower 147 filled with a cation exchange resin is adopted as an acidifying means for acidifying the chlorite diluted solution. ing. The chlorite diluted solution sent from the ejector 120 is acidified by passing through the cation exchange resin column 147.

Next, the chlorite solution acidifying apparatus 800 according to the eighth embodiment of the present invention will be described with reference to FIG. FIG. 8 is designated by the same reference numeral, and detailed description thereof will be omitted. In this embodiment, a configuration different from the fifth embodiment of the present invention will be mainly described.

The chlorite solution acidifying device 800 according to the eighth embodiment of the present invention includes a flow rate controller 110, an ejector 120, and an intermittent metering pump 130. It also has a solenoid valve 160. The solenoid valve 160 can be omitted as appropriate. In the chlorite solution acidifying device 800, a hydrochloric acid solution, which is an acidic solution, is added to the ejector 120 as an acidifying means for acidifying the chlorite diluted solution. Specifically, water is circulated to the ejector 120 by the flow rate controller 110, and the chlorite solution and the hydrochloric acid solution are injected into the suction portion of the ejector 120. The ejector 120 has two suction portions, and a chlorite solution and a hydrochloric acid solution are injected into different suction portions. Further, in the chlorite solution acidifying device 800, a diaphragm type pump is used for the intermittent metering pump 130.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

<Example 1>
A chlorine dioxide solution was generated using the chlorine dioxide solution generator 100 shown in FIG. As a condition, raw water of 0.25 MPa was supplied into the chlorine dioxide solution generator 100. The flow rate was set to 80 mL / min with the metering valve which is the flow rate controller 110. As the intermittent metering pump 130, a diaphragm type pump was used, and 25% sodium chlorite was injected into the ejector 120 at 1.32 g / min. The sodium chlorite diluted solution discharged from the outlet side of the ejector 120 is acidified in the three-chamber electrolytic cell 140, and the acidified sodium chlorite diluted solution passes through the catalyst reactor 150 and is a chlorine dioxide solution. Was generated. The three-chamber type electrolytic cell 140 used in Example 1 used the following.

<Three-chamber type electrolytic cell configuration>
-Ion exchange room: Inner dimensions 210 x 127 x 15 mm
-Anode chamber, cathode chamber: internal dimensions 210 x 127 x 20 mm
・ Anode, cathode: Platinum coated titanium electrode, electrode plate area (wet contact area): 267 cm ² Electrodes distance: 16 mm
-Ion exchange resin: UBK-16 (Mitsubishi Chemical Corporation), 310 mL
-Cation exchange membrane: Nafion (registered trademark) 117 (The Chemours Company), effective membrane area 267 cm ²

Next, the sodium chlorite diluted solution discharged from the ejector 120 and the chlorine dioxide solution discharged from the catalyst reactor 150 were collected over time, and their concentrations were analyzed by a titration method. In addition, the amount of chlorine dioxide solution produced was also measured in the same manner, and the change over time up to 1000 hours of operation was confirmed. The confirmed results are shown in FIG. From FIG. 9, the concentration of the sodium chlorite diluted solution (described as the chlorate ion concentration), the chlorine dioxide solution concentration, and the chlorine dioxide solution production amount showed almost no change in the continuous operation for 1000 hours, and were stable. It was confirmed that a chlorine dioxide solution could be produced.

<Example 2>
A chlorine dioxide solution was generated using the chlorine dioxide solution generator 200 shown in FIG. As a condition, as in Example 1, raw water of 0.25 MPa was supplied into the chlorine dioxide solution generator 200. The flow rate was set to 80 mL / min. The flow rate controller 110 uses a proportional control valve, and a flow meter 190 is provided between the water softener 180 and the ejector 120. The flow rate adjustment was performed by automatically controlling the opening degree of the proportional control valve based on the analog signal of the flow rate output from the flow meter 190. The test was conducted under the same conditions as in Example 1 except for the flow rate adjustment, and it was confirmed that a chlorine dioxide solution was stably produced.

<Example 3>
A chlorine dioxide solution was produced using the chlorine dioxide solution generator 300 shown in FIG. As a condition, as in Example 1, raw water of 0.25 MPa was supplied into the chlorine dioxide solution generator 300. The flow rate was set to 80 mL / min. The sodium chlorite diluted solution discharged from the ejector 120 was acidified through the cation exchange resin tower 147 to generate a chlorine dioxide solution in the catalytic reactor 150. Except for the acidification means, it was confirmed that the chlorine dioxide solution was stably produced in the test under the same conditions as in Example 1. The capacity of the cation exchange resin tower 147 used in Example 3 was 500 ml.

<Example 4>
A chlorine dioxide solution was produced using the chlorine dioxide solution generator 400 shown in FIG. As a condition, as in Example 1, raw water of 0.25 MPa was supplied into the chlorine dioxide solution generator 400. The flow rate was set to 80 mL / min. As the intermittent metering pump 130, a 25 wt% chlorite solution and a 10 wt% hydrochloric acid solution were injected into the ejector 120 having two suction parts from different suction parts using a diaphragm type pump. The chlorite solution diluted and acidified in the ejector was then sent to the catalytic reactor 150 to produce a chlorine dioxide solution. In addition, since chlorite causes a disproportionation reaction immediately after acidification and the chlorite ion decreases, the concentration of the chlorite diluted solution is not measured in Example 4. However, as in Examples 1 to 3, it was confirmed that the concentration and the amount of chlorine dioxide solution produced remained stable.

Next, the catalyst of the catalyst reactor 150 was examined. Specifically, changes in the concentration of the chlorine dioxide solution due to changes in the amount of platinum supported on the catalyst (platinum alumina catalyst) packed in the catalyst reactor 150 were investigated. The catalyst used is shown below.

<Adjustment of platinum alumina catalyst>
Spherical activated alumina Al ₂ O ₃ (particle size φ2-4 mm, pore volume 0.51 mL, specific surface area 160 m ² / g) is impregnated into a dinitrodiammine platinum aqueous solution prepared to a predetermined concentration, and 0.01 in terms of metallic platinum. It was adsorbed so as to be mass%, 0.11% by mass, 0.17% by mass, 0.25% by mass, and 0.50% by mass. This was dried at 100 ° C. for 20 minutes and then calcined in the air at 450 ° C. for 5 hours to obtain a platinum alumina catalyst.

The chlorine dioxide solution was produced in the same configuration as the device of the chlorine dioxide solution generation device 100 of Example 1, except that the platinum alumina catalyst was used. Table 1 showing the concentration of the chlorine dioxide solution due to the change in the amount of platinum carried is shown below. In addition, the platinum carrying amount of Example 5 was 0.01% by mass, the platinum carrying amount of Example 6 was 0.11% by mass, and the platinum carrying amount of Example 7 was 0.17% by mass, and Example 8 was taken. The platinum carrying amount is 0.25% by mass, and Comparative Example 1 is the platinum carrying amount: 0.50% by mass. The chlorine dioxide yield of Example 5 was 88.1%, the chlorine dioxide yield of Example 6 was 85.2%, the chlorine dioxide yield of Example 7 was 82.5%, and the chlorine dioxide yield of Example 8 was. Showed a high value of 72.1%. In Comparative Example 1, the chlorine dioxide yield was as low as 61.0%.

<Table 1>

The chlorine dioxide solution generator according to the present invention is useful because it can stably generate a chlorine dioxide solution having a constant concentration for a long period of time.

100, 200, 300, 400 Chlorate dioxide solution generator 500, 600, 700, 800 Chlorite solution acidifier 110 Flow controller 120 Ejector 130 Intermittent metering pump 140 Three-chamber type electrolytic cell 141 Agitator 142 Ion chamber 143 Cathode 144 Cathode chamber 145 Ion exchange chamber 146 Cation exchange membrane 147 Cation exchange resin tower 150 Catalyst reactor 160 Electromagnetic valve 170 Needle valve 180 Water softener 190 Flow meter

Claims (9)

A chlorine dioxide solution generator that acidifies chlorite solutions and converts the acidified chlorite solutions into chlorine dioxide solutions.
An intermittent metering pump that feeds the chlorite solution,
A flow rate controller for circulating a fixed amount of water for diluting the chlorite solution, and
An ejector for mixing the chlorite solution and the water to obtain a chlorite diluted solution having a uniform concentration,
An acidifying means for acidifying the chlorite diluted solution and
A chlorine dioxide solution generating apparatus comprising: a catalytic reactor for converting a chlorite diluted solution acidified by the acidifying means into a chlorine dioxide solution. The chlorine dioxide solution generating apparatus according to claim 1, wherein the ejector has at least one suction portion, and the suction portion and the intermittent metering pump are connected to each other. The chlorine dioxide solution generating device according to claim 1 or 2, wherein the flow rate controller is a constant flow rate valve. The chlorine dioxide solution generator according to any one of claims 1 to 3, wherein the intermittent metering pump is a diaphragm type pump. The chlorine dioxide solution generating apparatus according to any one of claims 1 to 4, wherein the amount of the chlorine dioxide solution produced is 0.001 to 1 L / min. The chlorine dioxide solution generating apparatus according to any one of claims 1 to 5, wherein the concentration of the chlorite solution is 1 to 10000 mg / L as a chlorite ion concentration. The chlorine dioxide according to any one of claims 1 to 6, wherein the catalyst reactor comprises a platinum alumina catalyst in which platinum is supported on an activated alumina carrier in an amount of 0.01 to 0.25% by mass. Solution generator. The chlorine dioxide solution generating apparatus according to claim 7, wherein the activated alumina carrier has a specific surface area value of 50 to 300 m ² / g and a particle diameter of 0.1 to 10 mm. A chlorite solution acidifier that acidifies chlorite solutions.
An intermittent metering pump that feeds the chlorite solution,
A flow rate controller for circulating a fixed amount of water for diluting the chlorite solution, and
An ejector for mixing the chlorite solution and the water to obtain a chlorite diluted solution having a uniform concentration,
A chlorite solution acidifying apparatus comprising: an acidifying means for acidifying the chlorite diluted solution.

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