JPH07277703A - Method for generating chlorine dioxide and system therefor - Google Patents

Abstract

PURPOSE:To provide a chlorine dioxide generating method and system so designed that an aqueous solution of chlorate and an aqueous hydrochloric acid are made to flow in specific modes, respectively, and when chlorine dioxide generation is halted, controlling water flow is made higher for a specified time than that during its genera tion, thereby preventing the corrosion of a premixing chamber and explosion. CONSTITUTION:Control valves 16, 17, 18 are regulated to bring the respective scale readings of flowmeters 10, 11, 12 to respective specified values during chlorine dioxide generation, and after confirming the color of a mixed fluid from a reaction state monitoring chamber 8, the control valves 16, 17, 18 are set, and chlorine dioxide is then generated and discharged, together with diluting water, into a diluting water discharge pipe 4. On the contrary, the control valves 16, 17 are closed while chlorine dioxide generation is halted, and the flow of an aqueous solution of chlorate and an aqueous hydrochloric acid is halted to regulate the control valve 18 to make control water flow higher than that during chlorine dioxide generation and ensure controlling water alone to flow in the mixing pipe 5. After the controlling water is allowed to flow for a specified time, the control valve 18 is closed to halt operation of the chlorine dioxide generator 6.

Description

Description: TECHNICAL FIELD The present invention relates to a chlorine dioxide generating method and apparatus for reacting a chlorate with hydrogen chloride to generate chlorine dioxide.

(Prior Art) Chlorine dioxide is widely used for the purposes of bleaching paper and fibers, disinfecting water, deodorizing, etc. However, since chlorine dioxide is corrosive and explosive, it is generally manufactured by an appropriate method at the place of use. Therefore, it is desirable to be effectively manufactured by a relatively small-scale facility.

 As a method of generating chlorine dioxide that satisfies these requirements, an aqueous solution of chlorite is reacted with chlorine gas in a premixing chamber, and diluting water is made to flow through a venturi throat to generate a negative pressure. There is a method of inhaling chlorine dioxide and discharging it together with dilution water (see Japanese Patent Laid-Open No. 61-183104).

(Problems to be Solved by the Invention) According to the method described in JP-A No. 61-183104, chlorine dioxide can be effectively generated in a small reaction apparatus, but when the reaction apparatus is stopped. Chlorine dioxide may accumulate in the premix chamber, corrode the premix chamber, and if high pressure is applied, chlorine dioxide may explode.

In particular, if the flow rate of the diluting water is extremely reduced due to a failure of the diluting water flow device or water interruption, the premixing chamber will have an extremely high pressure and the risk of chlorine dioxide explosion will increase.

 In view of these problems, the present invention provides a method for preventing corrosion of the premixing chamber due to retention of chlorine dioxide and preventing explosion of chlorine dioxide due to high pressure in the premixing chamber. Furthermore, it provides an apparatus used for carrying out this method.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the method for generating chlorine dioxide of the present invention is to form a negative pressure chamber in a flow path of dilution water, and to form an aqueous solution of chlorine oxygen and hydrogen chloride. A mixed fluid of an aqueous solution and control water is caused to flow into the negative pressure chamber, the generated chlorine dioxide is sucked into the flow pipe and is allowed to flow out together with the diluting water. Flow the aqueous solution, the aqueous solution of hydrogen chloride, and the control water at a predetermined flow ratio.When the generation of chlorine dioxide is stopped, the flow of the aqueous solution of chlorate and the aqueous solution of hydrogen chloride is stopped, and the flow rate of the control water is changed to the generation of chlorine dioxide. The present invention is characterized in that the supply of control water is stopped after the fluid has been allowed to flow for a certain period of time, and the chlorine dioxide generating device of the present invention is provided with a diluting water flow conduit and this flow conduit. The negative pressure chamber provided inside and salt in this negative pressure chamber A mixing pipe into which a mixed fluid of an aqueous solution of chlorate, an aqueous solution of hydrogen chloride and control water flows, and a supply means for separately supplying the aqueous solution of chlorate, the aqueous solution of hydrogen chloride and control water to the mixing pipe. It is characterized in that an adjusting means for separately adjusting the flow rates of the aqueous solution of chlorate, the aqueous solution of hydrogen chloride and the control water is provided.

(Operation) When chlorine dioxide is generated, it is possible to effectively generate chlorine dioxide by flowing an aqueous solution of chlorate, an aqueous solution of hydrogen chloride, and control water at a predetermined flow rate ratio. By stopping the flow of the aqueous solution of chlorate and the aqueous solution of hydrogen chloride and flowing the control water at a flow rate higher than that at the time of chlorine dioxide generation for a certain period of time, chlorine dioxide in the mixing pipe is removed and mixing due to retention of chlorine dioxide is carried out. Prevents chlorine dioxide from exploding due to pipe corrosion and high pressure.

(Examples) Examples of the present invention will be described in detail with reference to the drawings.

 FIG. 1 is a sectional view of the chlorine dioxide inhaler of the present invention. A negative pressure chamber 2 is defined in the chlorine dioxide inhaler 1, and in the negative pressure chamber 2, one end 3a of a dilution water inflow pipe 3, one end 4a of a dilution water outflow pipe 4, a mixing pipe. One end 5a of each of the 5 is open. The one end 3a of the diluting water inflow pipe 3 and the one end 4a of the diluted water outflow pipe 4 constitute a Venturi pipe, and the pipe diameter of the one end 3a is gradually reduced toward the downstream side. Is designed to gradually contract toward the downward flow and then gradually expand so that the negative pressure chamber 2 is depressurized when the dilution water is made to flow.

 The dilution water flows into the negative pressure chamber 2 through the arrow A and flows out from the negative pressure chamber 2 through the arrow B. On the other hand, the generated chlorine dioxide and control water flow into the negative pressure chamber 2 through the arrow C. At this time, since the inside of the negative pressure chamber 2 is depressurized, chlorine dioxide and the control water are sucked from one end 4a of the dilution water outflow pipe 4 and flown out along with the dilution water from the arrow B.

 The feature of the present invention is to control the flow rate of the control water. That is, when chlorine dioxide is generated, an aqueous solution of chlorate, an aqueous solution of hydrogen chloride and control water are flowed at a predetermined flow rate ratio to effectively generate chlorine dioxide, and when chlorine dioxide is stopped, chloric acid is generated. After stopping the flow of the salt aqueous solution and the hydrogen chloride aqueous solution, make the flow rate of the control water larger than that when chlorine dioxide was generated, and flow the control water only into the mixing pipe 5 for a certain time, then stop the flow of the control water. It is something.

 FIG. 2 is an external view of the chlorine dioxide generator of the present invention. The chlorine dioxide suction device 1 is installed on a base 7 of the chlorine dioxide generation device 6, and the dilution water inflow pipe 3, the dilution water outflow pipe 4, and the mixing pipe 5 are connected to the chlorine dioxide suction device 1.

 The other end 5b of the mixing tube 5 serves as an inflow portion for an aqueous solution of chlorate, an aqueous solution of hydrogen chloride, and control water. A bent portion 5c is provided between the one end portion 5a and the other end portion 5b. A reaction state observation chamber 8 made of transparent glass is installed in the conduit of 5c so that the reaction state of the mixed fluid flowing in the mixing pipe 5 can be observed, and between the other end 5b and the bent portion 5c. A layered annular portion 5d is provided on the inner wall so that the chlorate and hydrogen chloride are completely reacted.

 In addition, a support plate 9 is erected on the base 7, and on the support plate 9, flow rate meters 10, 11 and 12 of chlorate solution, hydrogen chloride solution and control water are fixed and supported. is there.

 The chlorate aqueous solution, the hydrogen chloride aqueous solution, and the control water flow in through the lower end openings 10a, 11a, 12a of the flowmeters 10, 11, 12 respectively, and the upper end openings 10b, 11b, 12b, the thin tubes 13, 14 are provided. , 15 to flow into the other end 5b of the mixing pipe 5. In addition, adjusting valves 16, 17 and 18 for adjusting the flow rate are provided in the conduits of the thin tubes 13, 14 and 15, and the other end portion 5b of the mixing tube 5 is provided to prevent backflow. Check valves 19, 20 and 21 are provided.

 Therefore, when chlorine dioxide is generated, adjust the adjusting valves 16, 17 and 18 so that the scales of the flowmeters 10, 11 and 12 are set to predetermined values, and check the color of the mixed fluid flowing from the reaction state observation chamber 8 The adjusting valves 16, 17 and 18 are set to generate chlorine dioxide, and the chlorine dioxide is discharged to the dilution water outflow pipe 4 together with the dilution water.

 On the other hand, when the generation of chlorine dioxide is stopped, the adjusting valves 16 and 17 are closed, the flow of the aqueous solution of chlorate and the aqueous solution of hydrogen chloride is stopped, the adjusting valve 18 is adjusted, and the flow rate of the control water is changed to chlorine dioxide. The control water is allowed to flow in the mixing pipe 5 as much as possible. After flowing the control water for a certain period of time, the regulating valve 18 is closed and the chlorine dioxide generator 6 is stopped.

 If the flow device for dilution water fails or is cut off, the adjusting valves 16 and 17 are immediately closed to stop the flow of the aqueous solution of hydrochloride and the aqueous solution of hydrogen chloride, and the adjusting valve is closed. 18 may be adjusted to force only the control water to flow into the mixing tube 5.

(Effects of the Invention) According to the chlorine dioxide generation method of the present invention, chlorine dioxide does not stay in the mixing pipe when chlorine dioxide generation stops, the mixing pipe is not corroded, and the pressure rises to explode. There is no danger of doing it. Therefore, it is possible to generate highly safe chlorine dioxide over a long period of time.

 Furthermore, even if the dilution water becomes inoperable due to failure of the dilution water flow device or water interruption, the control water will be forced to flow and the chlorine dioxide etc. in the mixing pipe will be removed. There is no danger of explosion.

 According to the chlorine dioxide generator of the present invention, chlorine dioxide can be effectively generated and removed by the above method.

[Brief description of drawings]

 FIG. 1 is a sectional view of the chlorine dioxide inhaler, and FIG. 2 is an external view of the chlorine dioxide generator. 2 ... Negative pressure chamber, 3 ... Diluting water inflow pipe, 4 ... Diluting water outflow pipe, 5 ... Mixing pipe, 6 ... Chlorine dioxide generator, 10, 11, 12 ... Flowmeter, 13, 14, 15 ... Thin pipe, 16, 17, 18 ... Regulator valve.

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Claims (2)

[Claims] 1. A negative pressure chamber is formed in a flow path of dilution water, and a mixed fluid of an aqueous solution of chlorate, an aqueous solution of hydrogen chloride, and control water is allowed to flow into the negative pressure chamber to generate chlorine dioxide. To be discharged together with the dilution water, and when chlorine dioxide is generated, the chlorine dioxide solution of the chlorate solution and the control water are made to flow at a predetermined flow rate ratio to stop the generation of chlorine dioxide. At times, it may be necessary to stop the flow of the chlorate aqueous solution and the hydrogen chloride aqueous solution, make the flow rate of the control water larger than that at the time of chlorine dioxide generation, and allow it to flow for a certain period of time, and then stop the flow of the control water. Characteristic method of generating chlorine dioxide. 2. A diluting water flow pipe, a negative pressure chamber provided in this flow pipe, and a mixed fluid of an aqueous solution of chloric acid and hydrogen chloride and control water flowing into the negative pressure chamber. The mixing pipe, the supply means for supplying the chlorate aqueous solution, the hydrogen chloride aqueous solution and the control water separately to this mixing pipe, and the flow rates of the chlorate aqueous solution, the hydrogen chloride aqueous solution and the control water separately. A chlorine dioxide generator characterized in that it is provided with an adjusting means for adjusting to.