WO2013027959A1

WO2013027959A1 - Apparatus and method for generating chlorine dioxide

Info

Publication number: WO2013027959A1
Application number: PCT/KR2012/006448
Authority: WO
Inventors: 김성종; 장재화; 정상기; 기대윤
Original assignee: Kim Seong Jong; Jang Jae Hwa; Jung Sang Ki; Ki Dae Yoon
Priority date: 2011-08-25
Filing date: 2012-08-13
Publication date: 2013-02-28
Also published as: KR101092818B1

Abstract

The present invention relates to an apparatus and method for generating chlorine dioxide, and more specifically, to an apparatus and method for generating chlorine dioxide which generate chlorine dioxide (ClO₂) by reacting an aqueous sodium chlorite (NaClO₂) solution with hydrochloric acid (HCl), create an aqueous chlorine dioxide solution having an acidic pH value by passing the unreacted aqueous sodium chlorite (NaClO₂) solution again through an ion exchange bath including a strongly acidic cation exchange resin, and continuously generate chlorine dioxide without a generation apparatus for a separate ion exchange resin so that overall reaction time can be reduced and the generation efficiency of chlorine dioxide can be enhanced.

Description

Chlorine dioxide generator and its method

The present invention relates to a chlorine dioxide generating device and a method thereof, and more particularly, to remove odors generated from sewage and wastewater treatment devices or to generate chlorine dioxide for sterilizing effluent and treated water generated in various water treatment devices. In the process, sodium chlorite (NaClO ₂ ) aqueous solution and hydrochloric acid (HCl) are reacted to generate chlorine dioxide (ClO ₂ ), and the unreacted sodium chlorite aqueous solution is passed through an ion exchange bath containing a strongly acidic cation exchange resin to pH A chlorine dioxide generator and method for producing a chlorine dioxide aqueous solution and continuously generating chlorine dioxide without a separate ion exchange resin regeneration device can shorten the overall reaction time and increase the generation efficiency of chlorine dioxide. will be.

There is a growing interest in chlorine dioxide (ClO ₂ ), which can be used as a disinfectant in place of chlorine.

Unlike chlorine disinfectant disinfectants, chlorine dioxide is an oxygen disinfectant disinfectant. It does not react with ammonia to produce chloroamine, and reacts with organic substances in water to react with trihalomethane (THMs) or haloacetic acid (HAAs). It does not produce carcinogenic disinfection by-products.

In addition, chlorine dioxide has been actively researched through various papers as disinfectant of fruits, vegetables or aquatic products other than effluent disinfection in sewage treatment plants, algae removal, swimming pool disinfection, ballast water treatment, and cooling tower water.

In addition, chlorine dioxide is recognized as a deodorant that effectively removes hydrogen sulfide, mercaptan, and amines as an extensive deodorant, and is recognized as an oxidant that effectively removes odors in water by removing phenol, iron, and manganese in water.

Various methods and devices are introduced through domestic and international patents and methods for producing chlorine dioxide having such advantages.

Chlorine dioxide can be largely prepared by four methods, and the methods are as follows.

(1) Production of Chlorine Dioxide from Chlorine and Sodium Chlorite (NaClO ₂ )

2NaClO ₂ + Cl ₂ 2ClO ₂ + 2NaCl

(2) Production of chlorine dioxide from sodium hypochlorite (NaOCl), acid (Acid) and sodium chlorite (NaClO ₂ )

NaOCl + HCl NaCl + HOCl

HOCl + 2NaClO ₂ + HCl 2ClO ₂ + 2NaCl + H ₂ O

(3) Production of Chlorine Dioxide from Acid (Acid) and Sodium Chlorite (NaClO ₂ )

5NaClO ₂ + 4HCl 4ClO ₂ + 5NaCl + 2H ₂ O

10NaClO ₂ + 5H ₂ SO ₄ 8ClO ₂ + 5Na ₂ SO ₄ + 4H ₂ O

(4) Production of Chlorine Dioxide by Electrolysis of Sodium Chlorite (NaClO ₂ )

Cation region: NaClO ₂ Na + + ClO _2-

Anion region: H ₂ O H + + OH-

Each of the four methods presented above has advantages and disadvantages. The method using chlorine gas has a high yield and generates little by-product, but it is not easy to store or handle chlorine gas.

The production method using sodium hypochlorite and acid is a method that can obtain a yield of about 80% in the absence of chlorine, but the reaction itself is complicated and the storage of raw materials is more complicated than other methods because the reaction must proceed with the input of three raw materials. There is an uncomfortable problem.

The production method using hydrochloric acid or sulfuric acid has the advantage of generating a large amount of chlorine dioxide in a short time, but there is a problem in that a lot of by-products are produced compared to other methods. For example, depending on the reaction conditions and raw materials of chemical reactions, chlorate ions, salts thereof, sodium chloride, etc. are contained as by-products. Among them, chlorite ions react with hemoglobin in the body and cause cyanosis. The concentration of chlorine dioxide is less than 1 ppm in drinking water.

The recently introduced electrochemical method using a membrane-free electrolytic cell can produce high purity chlorine dioxide because less by-products are produced than other methods. However, OH-ion is generated during electrolysis to raise the pH inside the electrolytic cell. Chlorine dioxide is changed into chlorate chlorite (ClO _2- ), chlorate (ClO _3- ), there is a problem that the concentration of reacted chlorine dioxide falls. In addition, there is a problem in that NaCl is precipitated on the electrode during the continuous electrolysis process, thereby inhibiting the electrolysis efficiency.

The present invention is to solve the problems of the conventional methods for producing chlorine dioxide, in particular, the purity of chlorine dioxide pointed out as a problem in the way to produce chlorine dioxide using sodium chlorite (NaClO ₂ ) and acid (Acid) In order to solve the problem of low efficiency and low efficiency, an ion exchange tank is installed at the rear of the reactor, and the yield of the entire chlorine dioxide generator is improved by converting unreacted sodium chlorite discharged from the reactor into chlorine dioxide through the ion exchange tank. I want to increase.

In addition, the present invention is to separate the regeneration device or regeneration wastewater treatment facility by eliminating the problems caused during regeneration by automating the regeneration process frequently generated in the use of the ion exchange resin or at the same time in the process of generating chlorine dioxide The present invention provides an efficient, eco-friendly and economical chlorine dioxide generator and its method by improving the disadvantages of shortening the operation time of the apparatus due to the regeneration and the disadvantages of the complexity of the apparatus such as the need for regeneration equipment.

As a means for achieving the above object of the present invention, the chlorine dioxide generator according to the present invention,

A reaction tank for producing an aqueous chlorine dioxide (ClO ₂ ) solution by reacting an aqueous solution of sodium chlorite (NaClO ₂ ) with hydrochloric acid (HCl);

It includes an ion exchange tank for injecting an aqueous solution of chlorine dioxide (ClO ₂ ) discharged from the reaction tank to convert unreacted sodium chlorite contained in the aqueous solution of chlorine dioxide to an aqueous solution of chlorine dioxide using a strong acid cation exchange resin.

The reaction mechanism in the reactor is shown in the following scheme.

Scheme 1

5NaClO ₂ + 4HCl ------ 4ClO ₂

In the ion exchange tank, Na + ions of sodium chlorite (NaClO ₂ ) are exchanged with H + of the cation exchange resin using ion selectivity of the cation exchange resin to generate an aqueous solution of chlorine dioxide (ClO ₂ ) and H + ions.

The reaction mechanism in the ion exchange tank is shown in the following scheme.

Scheme 2

R-SO ₃ H-H + + NaClO ₂ ----- R-SO ₃ H-Na + + ClO ₂ + H +

As described above, in the chlorine dioxide generator according to the present invention, an ion exchange tank filled with a cation exchange resin is installed at the rear end of the reactor to convert unreacted sodium chlorite into an aqueous solution of chlorine dioxide. That is, the product generated in the reaction tank in which the chemical reaction occurs contains H + ions so that the pH is kept acidic, and not only chlorine dioxide but also sodium chlorite which has not been reacted in the reaction tank in the state of incomplete reaction ( chlorite (ClO _2- ), chlorate (ClO _3- )). Therefore, the ion exchange tank converts the unreacted sodium chlorite and chlorate ions discharged from the reactor into chlorine dioxide.

At this time, the cation exchange resin (cation exchange resin) has a structure in which a cation exchange group is bonded to the polymer body, the polymer body of the cation exchange resin is a copolymer of styrene (stylene) and divinyl benzenr (DVB) Mainly used, it is a structure in which a cation exchanger is bonded to a polymer body having a fine three-dimensional network structure as spherical particles. That is, the cation exchange resin is an ion exchange resin combined with a sulfuric acid group (-SO ₃ H), and when the cation exchange resin is immersed in water, the cation exchange group portion is ionized similarly to the inorganic acid as shown in the following reaction formula.

Scheme 3

-SO ₃ H --------- R-SO _3- + H +

In this case, R represents a polymer body, and since -SO ₃ -bonded to the polymer body cannot move freely, it is referred to as a 'fixed ion', and is opposed to an H +, which is a movable ion that is electrically neutralized by binding to a fixed ion. Ion ', in the end, the cation exchange reaction by the cation exchange resin is the exchange of these allions.

Since the cation exchange resin alleles are replaced by cations such as Ca ++, Mg +, Na + and K +, the cation must be reduced to H + to reuse the cation exchange resin. Reduction is a process of reducing the state to form R-SO ₃ H.

For example, in order to regenerate the R-SO ₃ Na type cation exchange resin in which the H + is substituted with Na + in the cation exchange resin, the spent cation exchange resin is deposited on an aqueous hydrochloric acid solution or an aqueous sulfuric acid solution, and then R-SO ₃ H It must be reproduced in sentence.

Scheme 4

R-SO ₃ Na + HCl ---------- R-SO ₃ H + NaCl

2 R-SO ₃ Na + H ₂ SO ₄ ---------- 2 R-SO ₃ H + Na ₂ SO ₄

Therefore, the ion exchange tank of the present invention requires a regeneration device for regenerating a cation exchange resin having lost ion exchange capacity.

However, the conventional ion exchange resin regeneration device for regenerating cation exchange resins used in various fields such as pure water treatment facilities or pure water treatment facilities in the semiconductor industry is deposited in strong acid solutions such as hydrochloric acid and sulfuric acid, and then demineralized water. Because it is washed with water, it takes a long time to regenerate the ion exchange resin and the regeneration efficiency is low, and a large amount of regeneration waste liquid is generated due to the large use of chemicals during regeneration, and a separate waste water treatment device for waste water treatment is required. And the operation was very complicated and had a limitation that can not easily and economically recover the ion exchange resin.

In particular, the conventional ion exchange resin regeneration method stops the operation of the chlorine dioxide generating device at regular intervals and injects a regenerant into the ion exchange tank, so that the contact time between the regenerant and the cation exchange resin is appropriate (30 to 50 minutes). Since the system must be washed with demineralized water after the maintenance, the operation time of the device is shortened due to the regeneration, and the device becomes complicated due to the need of regeneration equipment such as the regeneration agent storage tank, the regeneration agent supply pump, and the regeneration agent supply line. In addition, by injecting a large amount of regenerant in a short time, a large amount of chemical consumption occurs and the problem of shortening the life of the cation exchange resin due to the osmotic pressure.

In order to solve this problem, the chlorine dioxide generator according to the present invention is not provided with a regenerant for regeneration of the cation exchange resin, the amount of hydrochloric acid used to generate chlorine dioxide according to the hydrogen ion concentration of the ion exchange tank By determining and injecting it, the concentration of hydrogen ions in the ion exchange tank is lowered so that the cation exchange resin can be used continuously without a separate regeneration process.

In addition, by injecting hydrochloric acid into the reaction tank more than the amount of hydrochloric acid required to generate chlorine dioxide by reacting with sodium chlorite in the reaction tank is configured to proceed with the regeneration process simultaneously with the chlorine dioxide generation process without a separate regeneration process or regeneration device do.

As described above, the present invention injects sodium chlorite and hydrochloric acid into the reaction tank to generate chlorine dioxide, and the aqueous solution supplied to the ion exchange tank by injecting chlorine dioxide and unreacted sodium chlorite generated in the reaction tank into the ion exchange tank. The unreacted sodium chlorite in the reaction comprises the step of converting to chlorine dioxide, the amount of hydrochloric acid supplied to the reaction tank is injected into the reaction tank with sodium chlorite more than the amount necessary to generate chlorine dioxide is supplied to the reactor A portion of the hydrochloric acid thus obtained is introduced into the ion exchange tank, so that unreacted sodium chlorite is converted to chlorine dioxide in the ion exchange tank, and an R-SO ₃ Na type cation exchange resin is converted into an R-SO ₃ H type cation exchange resin. It is characterized by reproducing.

According to the present invention, chlorine dioxide is generated by using an aqueous sodium chlorite solution and hydrochloric acid to generate chlorine dioxide, and after the chemical reaction, unreacted sodium chlorite is passed through an ion exchange tank including a strong acid cation exchange resin to generate chlorine dioxide without an unreacted substance. By complex reaction of expensive materials such as sodium chlorite without complex or dangerous equipment such as gas or sulfuric acid, it is possible to produce economical and high-purity chlorine dioxide because not only raw material cost is reduced but also impurities are almost absent after the reaction.

In addition, the regeneration process and replacement are indispensable in using the cation exchange resin, and it is a control panel capable of proportionally controlling the hydrogen ion concentration measuring device and the measured value so as to supply hydrochloric acid required for regeneration in addition to hydrochloric acid required for chemical reaction. It can be quantitatively injected as needed by controlling the injection amount of hydrochloric acid so that there is almost no loss of raw materials, and there is no need for a separate regeneration process, simplifying the structure of the device and replacing the replacement cycle with the existing regeneration process. It is economical because it can be kept long.

In addition, by quantifying the hydrochloric acid required for the chemical reaction with sodium chlorite and maintaining the pH of the aqueous solution to be acidic through the ion exchange tank, the chlorine ions are converted to chlorine dioxide, inhibiting the conversion of chlorine dioxide to chlorate ions As a result, even when stored for a long period of time, it is not converted to chlorate ions, thereby producing chlorine dioxide with higher purity and higher yield than conventional methods.

1 is a schematic configuration diagram of a chlorine dioxide generator using ion selectivity of a strong acid cation exchange resin according to an embodiment of the present invention,

2 is a molecular formula showing the conversion of sodium chlorite to chlorine dioxide by cation exchange resin,

Figure 3 is a molecular formula showing an example of a strong acid cation exchange resin,

Figure 4 is a flow chart showing a chlorine dioxide production method according to the present invention.

Hereinafter, a chlorine dioxide generator and a method thereof according to the present invention will be described in detail with reference to the accompanying drawings.

As shown in Figure 1, the chlorine dioxide generator of the present invention is a reaction tank 50 for generating chlorine dioxide (ClO ₂ ) by injecting sodium chlorite (NaClO ₂ ) aqueous solution and hydrochloric acid (HCl) aqueous solution, and the reaction tank And an ion exchange tank 60 for converting the unreacted sodium chlorite generated in the reaction tank 50 into an aqueous solution of chlorine dioxide using the ion selectivity of the strongly acidic cation exchange resin.

To this end, the reaction tank 50 is provided with a hydrochloric acid storage tank 10 for storing an aqueous hydrochloric acid (HCl) solution and a sodium chlorite raw material tank 11 for storing an aqueous solution of sodium chlorite (NaClO ₂ ).

In addition, a hydrochloric acid supply pump 20 for supplying an aqueous hydrochloric acid (HCl) solution to the reaction tank 50 is provided between the reaction tank 50 and the hydrochloric acid storage tank 10, and stores the reaction tank 50 and sodium chlorite. A sodium chlorite supply pump 21 for supplying an aqueous sodium chlorite (NaClO ₂ ) solution to the reaction tank 50 is provided between the tanks 11. At this time, between the reaction tank 50, the hydrochloric acid storage tank 10 and the sodium chlorite storage tank 11, the supply pumps 20, 21 are respectively installed and supply pipes for transferring sodium chlorite and hydrochloric acid (70) 71 is connected. In addition, the

supply pipes

70 and 71 may be further provided with a flow meter and a control valve (not shown) as necessary.

Subsequently, a rear end of the ion exchange tank 60 is provided with a chlorine dioxide storage tank 12 for storing the chlorine dioxide aqueous solution discharged from the ion exchange tank 60. A discharge pipe 80 is installed between the ion exchange tank 60 and the chlorine dioxide storage tank 12. And the discharge pipe 80 is provided with a pH meter 31 for measuring the hydrogen ion concentration of the aqueous solution discharged from the divorce exchange tank (60).

And the chlorine dioxide generating device of the present invention is provided with a control unit 40. The control unit 40 is for controlling the overall apparatus and is electrically connected to control the operational feed pump 20 and the sodium chlorite supply pump 21. In addition, the control unit 40 may be electrically connected to the water level sensor of the hydrochloric acid storage tank 10, the sodium chlorite storage tank 11 and the chlorine dioxide storage tank 12. In addition, the control unit 40 may be electrically connected to a switch for turning on / off the operation of the chlorine dioxide generating device and a display device for displaying an operation state.

In addition, the control unit 40 of the chlorine dioxide generating device according to the present invention may be electrically connected to the pH measuring device 31 to receive the pH value of the chlorine dioxide aqueous solution discharged from the ion exchange tank 60 in real time. .

In addition, the control unit 40 includes a program that can automatically control the hydrochloric acid supply pump 20 based on the pH measurement value provided from the pH meter 31. That is, the program controls the flow rate of the hydrochloric acid aqueous solution supplied to the reaction tank 50 in proportion to the hydrogen ion concentration. For example, when the pH is high, the amount of hydrochloric acid can be increased, and when the pH is low, the amount of hydrochloric acid can be reduced.

As such, the controller 40 may adjust the injection amount of the aqueous hydrochloric acid solution supplied to the reactor 50 according to the pH value of the aqueous chlorine dioxide solution discharged from the ion exchange tank 60.

That is, in the reactor 50, sodium chlorite (NaClO ₂ ) aqueous solution and hydrochloric acid (HCl) aqueous solution react to generate chlorine dioxide. In general, the generation efficiency of chlorine dioxide by such a chemical reaction takes a long time, Even if the drug is injected in excess of the reaction ratio, the maximum efficiency is less than 80%.

The present invention is to increase the overall reaction efficiency by converting the unreacted sodium chlorite to chlorine dioxide in the reaction tank 50 by further installing an ion exchange tank 60 at the rear end of the reaction tank 50 to compensate for this disadvantage. . Therefore, according to the present invention, when the drug is sufficiently injected, an efficiency of up to 100% can be expected.

In addition, the present invention converts the unreacted sodium chlorite to chlorine dioxide by measuring the hydrogen ion concentration of the aqueous solution discharged from the ion exchange tank 60 by sufficiently injecting hydrochloric acid used as a raw material By simultaneously regenerating the cation exchange resin, a separate regeneration process and a regeneration device can be omitted. That is, in the conventional ion exchange tank, the regeneration cycle is too short due to the oxidizing power of chlorine dioxide and high concentration of sodium chlorite when chlorine dioxide is generated. Therefore, there are economical disadvantages such as frequent regeneration and faster replacement cycles of resins.

However, the present invention, as shown in the following table and the embodiment, by measuring the hydrogen ion concentration of the ion exchange tank and by additionally injecting hydrochloric acid used as a raw material according to the concentration it was confirmed that chlorine dioxide generation and regeneration at the same time. This data was obtained through repeated experiments. When the amount of chlorine injected into the reactor was sufficiently increased, it was not necessary to regenerate the ion exchange resin and the replacement cycle of the ion exchange resin was longer than that of the regeneration process.

Hereinafter, a method for regenerating a cation exchange resin according to the present invention will be described.

When calculating the amount of cation exchange resin, the exchange capacity applied is usually expressed as ppm as CaCO ₃ , so it is applied as the 'g' exchange capacity converted into CaCO ₃ and converted into equivalents = atomic weight / ionic value. ₃ 1 equivalent = 100g / 2 = 50g as CaCO ₃ and the adsorption capacity of cation exchange resin is capable of adsorbing Na + ions of 1.7 meq / ml or more.

For example, if the exchange capacity of the cation exchange resin is 2.0 meq / ml resin, 50g × 2 = 100g, that is, 1L of cation exchange resin can remove 100g of cations converted to CaCO ₃ , and the valence of Na + is higher than that of Ca ²⁺ . Since it is half, 200g of Na + ions can be removed.

The regenerant is preferably used by diluting 35% HCl in volume by about 11 times (about 3.2%) and the amount of the antibiotic is carried out for 20 to 60 minutes within the range of 2 to 4 times per volume of the strongly acidic cation resin. It is desirable to.

After the cation exchange resin regeneration, the ion selectivity of the resin can be recovered to about 80%. When the pH of the pH meter is increased by 6 or more, it is preferable to replace the cation exchange resin.

Referring to FIG. 1 again, when HCl is injected into the strongly acidic cation exchange resin of the ion exchange tank 60, when the sodium chlorite is changed to chlorine dioxide, a high concentration of H + ions is returned to the cation exchange resin in chemical equilibrium. Is adsorbed on the sulfone group (SO ₃ −), and Na + ions are removed again. Since the desorbed Na + ions are combined with Cl-of HCl to form NaCl, after the reaction in the ion exchange tank 60, a regenerant is added to the cation exchange resin again so that the cation exchange resin does not need to be regenerated. The period can also be extended.

As described above, the ion exchange tank 60 exchanges Na + ions of sodium chlorite (NaClO ₂ ) with H + of the ion exchange resin by using the ion selectivity of the cation exchange resin to generate a chlorine dioxide aqueous solution and H + ions.

In addition, the product generated in the ion exchange tank 60 contains H + ions so that the pH is kept acidic, and based on this characteristic, the concentration of hydrogen ions is measured to supply hydrochloric acid, which is a regenerant, according to the change of the value. Give it. In addition, the controller 40 may be provided with a program for controlling the injection of a regenerant by converting the measured concentration of hydrogen ions.

As shown in the table below, injecting excess hydrochloric acid, ie, hydrochloric acid exceeding the amount of hydrochloric acid required to react with sodium chlorite to generate chlorine dioxide, shortens the reaction time, as well as the ion exchange tank 60. At cation exchange, the resin regeneration process occurs at the same time, thereby preventing economic losses due to the regeneration and replacement of the resin, and improving the generation efficiency of chlorine dioxide, thereby reducing the amount of expensive sodium chlorite.

Hereinafter, the examples in which chlorine dioxide is generated using the chlorine dioxide generator described above will be described.

Example 1

Sodium chlorite and hydrochloric acid were diluted to 6.25% and 5.0%, respectively, and injected into the reactor at a flow rate of 25 per minute. The chlorine dioxide generator used in this embodiment is to install the ion exchange tank 60 at the rear end of the reaction tank 50 as shown in FIG.

Example 2

The aqueous chlorine dioxide solution and the unreacted sodium chlorite from the reactor of Example 1 were diluted with water and made into a concentration of about 0.2%, and injected into the ion exchange tank, where the flow rate was 500 / min. The resin contained in the ion exchange tank was a styrene-divinylbenzene copolymer having a SO ₃ H group as an ion exchange group, that is, SCR-BH (trade name: TRILITE; manufactured by Samyang Corporation) as a cation exchange resin. The capacity of the ion exchange tank was filled with a cation exchange resin, and the inner diameter was 300 mm and the length was 40 cm. Three ion exchange baths were prepared and observed for each reaction.

Example 3

The injection amount was changed by comparing the amount of hydrochloric acid injected in Example 1 with the reaction ratio, and the experiment was performed by injecting at a concentration of about 5.0% to 12%, and the same conditions as in Example 2 were performed.

Example 4

Hydrogen ion concentration was measured at the rear end of the ion exchange tank in Example 2, and the experiment was performed by varying the concentration of hydrochloric acid according to the change of the concentration value, and the difference value was confirmed by experimenting under the same conditions as in Example 2.

Through the above embodiments, the results as shown in the following table were obtained.

Table 1

Chlorine Dioxide Concentration According to Reaction Ratio

Reaction ratio	1: 1	1: 2	1: 3	1: 4	Remarks
NaClO ₂ Concentration	10 ppm	10 ppm	10 ppm	10 ppm
HCl concentration
	10 ppm	20 ppm	30 ppm	40 ppm
ClO ₂ concentration	4 ppm	5 ppm	7 ppm	7.5 ppm

It was confirmed that the concentration of chlorine dioxide generated as the concentration of chlorine (HCl) injected into the reactor increases.

TABLE 2

Chlorine Dioxide Concentration According to Reaction Time

Reaction time	Injection cost	1 min	5 minutes	10 minutes	20 minutes	30 minutes	60 minutes	120 minutes
ClO ₂ concentration	1: 1	0.2	0.5	1.0	2.5	4.0	3.9	3.8
ClO ₂ concentration	1: 2	0.6	1.5	2.7	5.0	5.0	4.7	4.2
ClO ₂ concentration	1: 3	2.1	4.7	7.0	7.0	6.6	5.8	4.7
ClO ₂ concentration	1: 4	5.2	7.5	7.2	7.0	7.0	5.2	5.2

As the reaction time in the reactor increased, the concentration of chlorine dioxide increased. In the reaction time of 20-30 minutes, the concentration of chlorine dioxide increased maximally, but when the chlorine injection ratio (1: 4) was very large, the short reaction At time (5-10), the concentration of chlorine dioxide increased to the maximum.

TABLE 3

PH change of ion exchange resin

duration	Injection volume		1 min	30 minutes	60 minutes	120 minutes	180 minutes	240 minutes	300 minutes
NaClO ₂ Concentration	1: 1	2.1	2.2	2.2	2.3	2.3	4.7	6.1
NaClO ₂ Concentration	1: 2	2.2	2.4	2.5	4.6	6.2	6.6	6.7
NaClO ₂ Concentration	1: 3	2.2	2.5	4.1	4.7	5.9	6.5	6.9
NaClO ₂ Concentration	1: 4	2.2	3.8	4.8	6.0	6.7	6.9	6.9

As the reaction time of the ion exchange tank was increased, the pH was increased, and the pH reached 6 ~ 7 at the reaction time of 240 ~ 300 minutes, and the change of pH according to the reaction time was similar when the sodium chlorite injection ratio was 1: 2 or more. appear.

Table 4

PH Change of Ion Exchange Resin with Additional Injection of Hydrochloric Acid (HCl)

duration	Injection volume		1 min	30 minutes	60 minutes	120 minutes	180 minutes	240 minutes	300 minutes
NaClO ₂ Concentration	1: 1	2.1	2.2	2.2	2.3	2.3	1.8	1.6
NaClO ₂ Concentration	1: 2	2.0	2.4	1.7	2.0	1.9	1.6	1.6
NaClO ₂ Concentration	1: 3	1.8	2.0	1.8	1.8	1.7	2.0	1.5
NaClO ₂ Concentration	1: 4	1.6	1.7	1.8	2.0	1.6	1.5	1.7

When additional hydrochloric acid was injected, there was almost no pH change with the reaction time of the ion exchange bath. In particular, regardless of the sodium chlorite injection ratio, as the reaction time of the ion exchange bath increases, it was seen that the regeneration effect was large.

Table 5

Changes in pH of Ion Exchange Resins with Hydrochloric Acid (HCl) Injection Ratio

duration	Injection volume		1 min	30 minutes	60 minutes	120 minutes	180 minutes	240 minutes	300 minutes
HCl concentration	1: 1.0	2.1	2.2	2.2	2.3	2.3	4.7	6.1
HCl concentration	1: 1.2	2.1	2.1	2.1	2.2	2.2	4.5	5.5
HCl concentration	1: 1.5	2.0	2.0	2.0	2.0	2.0	3.1	3.5
HCl concentration	1: 2.0	2.0	1.9	1.9	2.0	2.0	2.5	2.5

When the addition ratio of hydrochloric acid is 1: 1.5 or more, it was found that the regeneration effect of the cation exchange resin was large.

Based on the above experimental results, the chlorine dioxide generation method according to the present invention, as shown in Figure 4, by generating a chlorine dioxide (ClO ₂ ) aqueous solution by chemically reacting sodium chlorite (NaClO ₂ ) aqueous solution and hydrochloric acid (HCl) Step (S100); Converting the aqueous chlorine dioxide solution and the unreacted sodium chlorite discharged from the step into an aqueous chlorine dioxide solution using a strong acid cation exchange resin (S200); Measuring the hydrogen ion concentration of the chlorine dioxide aqueous solution discharged in the step (S300); Controlling to increase or decrease the amount of hydrochloric acid supplied to the step (S100) based on the hydrogen ion concentration measured in the step (S400) is configured.

That is, in step S400, it is determined whether the measured pH value is equal to or greater than the reference value pH 2, and in step S500, the amount of hydrochloric acid is adjusted by the action of the hydrochloric acid supply pump.

On the other hand, when the injection ratio of hydrochloric acid is 1: 1.5 or more, it can be seen that the pH value is maintained at approximately 2 over time. Therefore, without installing the step (S400), the injection amount of hydrochloric acid required to react the amount of hydrochloric acid injected into the step (S100) with sodium chlorite (NaClO ₂ ) aqueous solution to chlorine dioxide (about 80% yield) to 1 From this point of view, when injected at 1.5 times of the time, a similar effect can be obtained by controlling the amount of hydrochloric acid injected based on the hydrogen ion concentration. In this case, the program for controlling the injection rate of the pH meter and hydrochloric acid can be omitted, thereby simplifying the configuration of the device.

As described above, the chlorine dioxide generator according to the present invention can not only increase the overall reaction efficiency by converting unreacted sodium chlorite in the reaction tank 50 to chlorine dioxide in the ion exchange tank 60, but also the ion exchange tank By injecting excessive hydrochloric acid in accordance with the hydrogen ion concentration of the aqueous solution discharged from (60) by converting unreacted sodium chlorite into chlorine dioxide in the ion exchange tank (60) and regeneration of the cation exchange resin and The playback device can be omitted.

In addition, even if the hydrogen ion concentration of the aqueous solution discharged from the ion exchange tank 60 is not measured, when the hydrochloric acid is injected above the amount of hydrochloric acid required to chemically react sodium chlorite with chlorine dioxide, the unreacted sodium chlorite is converted into chlorine dioxide. At the same time, the effect of regenerating the cation exchange resin can be simplified, thereby simplifying the construction of the device and extending the regeneration and exchange cycle of the cation exchange resin, thereby reducing the cost.

In addition, the present invention can reduce the concentration and the amount of acid used without generating by-products (such as salts containing Na) by generating chlorine dioxide through the strong acid cation exchange resin through the unreacted sodium chlorite after the chemical reaction It does not require installation cost, maintenance cost, reduction of production cost, and treatment of recycled water such as regeneration process of ion exchange resin and extension of resin replacement cycle. . And the chlorine dioxide produced according to the present invention is applicable to the field requiring chlorine dioxide aqueous solution, such as disinfection sterilization, algae removal, odor removal in the sewage treatment plant.

[Description of the code]

10: hydrochloric acid storage tank

11: Sodium Chlorite Storage Tank

12: chlorine dioxide storage tank

20: hydrochloric acid supply pump

21: sodium chlorite supply pump

31: hydrogen ion concentration measuring device

40: control unit

50: reactor

60: ion exchange tank

Claims

A reaction tank for producing an aqueous chlorine dioxide (ClO 2 ) solution by reacting an aqueous solution of sodium chlorite (NaClO 2 ) with hydrochloric acid (HCl);

An ion exchange tank for injecting an aqueous solution of chlorine dioxide (ClO 2 ) discharged from the reactor to convert unreacted sodium chlorite contained in the aqueous solution of chlorine dioxide into an aqueous solution of chlorine dioxide using a strong acid cation exchange resin;

PH measuring device for measuring the pH of the aqueous solution of chlorine dioxide discharged from the ion exchange tank;

A hydrochloric acid supply pump for controlling an injection amount of hydrochloric acid supplied to the reactor;

It is configured to include a control unit for controlling the hydrochloric acid supply pump according to the pH value measured by the pH meter,

The amount of hydrochloric acid injected into the reactor is injected 1.5 times as much as the amount of hydrochloric acid required to react the aqueous sodium chlorite solution with chlorine dioxide in the reactor, and the unreacted sodium chlorite is dissolved in the ion exchange bath using a strong acid cation exchange resin. Chlorine dioxide generation, characterized in that by converting to a portion of the hydrochloric acid injected in excess to recycle the cation exchange resin to extend the life of the cation exchange resin and to omit a separate regeneration process to improve the chlorine dioxide generation efficiency Device.