JP3770533B2 - Hypochlorite production equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for producing hypochlorite by electrolysis, and more particularly to an apparatus for producing hypochlorite with high safety when operation is stopped.
[0002]
[Prior art]
Hypochlorite typified by sodium hypochlorite is used as a flotation agent and disinfectant in various fields such as water and sewage treatment and drainage treatment for household kitchens and laundry. Hypochlorite can be produced by reacting alkali metal hydroxide obtained by electrolysis of an aqueous solution of alkali metal chloride such as saline with chlorine, or by using alkali metal chloride as a membrane. It is performed by a method in which electrolysis is performed in an electrolytic cell and hypochlorite is directly produced in the electrolytic cell. Since the method of reacting alkali metal hydroxide and chlorine can obtain a high concentration of hypochlorite, this method is used when manufacturing for the purpose of selling hypochlorite. However, since an electrolytic facility for producing alkali metal hydroxide and chlorine is required, it is carried out on a large scale in association with the production of sodium hydroxide or chlorine in an electrolytic plant for saline solution.
[0003]
On the other hand, a method of electrolyzing an aqueous solution such as salt in a diaphragm membrane electrolytic cell is also known. In this method, the concentration of hypochlorite produced is relatively low, but it is possible to produce a concentration that can be used directly for water purification and sterilization, and the production equipment is also hydroxylated. Since it is simpler than electrolytic equipment for producing alkali and chlorine, it is produced in the field where hypochlorite is required.
[0004]
FIG. 3 is a diagram illustrating an example of a conventional hypochlorite production apparatus.
[0005]
The hypochlorite production apparatus supplies saline 2 to the diaphragm-type electrolytic cell 1 for hypochlorite production, performs electrolysis in the diaphragm-type electrolytic cell, and the hypochlorite is the next. The generated hydrogen is supplied to the water seal safety device 5 through the chlorite conduit 3 and the hydrogen conduit 4, and the hydrogen is dissipated by keeping the liquid level in the water seal safety device 5 within a predetermined range. It is discharged to the outside through the pipe 6. Further, the hydrogen diffusion pipe 6 is supplied with air for diluting the hydrogen concentration by the dilution air pump 7 to reduce the hydrogen concentration to a safe level.
[0006]
On the other hand, hypochlorite is stored in the hypochlorite storage tank 8 from the water seal safety device and supplied to a desired place of use by the supply pump 9.
The electrolyzer may be intermittently operated according to the amount of hypochlorite used, but when the electrolyzer is stopped, hydrogen generated by electrolysis may stay in the electrolyzer. . If hydrogen stays in the electrolytic cell for a long time, there is a possibility of mixing with oxygen in the air, resulting in a risk of hydrogen explosion.
[0007]
[Problems to be solved by the invention]
An object of the present invention is to provide a hypochlorite production apparatus, in particular, a highly safe hypochlorite production in which hydrogen is prevented from staying in the electrolytic cell when the operation is stopped. It is an object to provide an apparatus.
[0008]
[Means for Solving the Problems]
The present invention relates to a hypochlorite production apparatus based on electrolysis of salt water, wherein a gas-liquid separator provided at the top of a diaphragm-type electrolytic cell is disposed, and an electrolyte surface is formed in the diaphragm-type electrolytic cell. An upper space is provided above the electrolyte surface in the electrolytic cell, and a riser pipe having one end of the opening located on the electrolyte surface and the other end of the opening connected to the gas-liquid separator is disposed. A small hole is provided in the upper space of the electrolytic cell. When the electrolytic cell is stopped, the electrolytic solution in the gas-liquid separator flows backward through the riser and hydrogen stays in the upper space of the electrolytic cell through the small hole. Is a hypochlorite production device that discharges the gas to a gas-liquid separator.
In the hypochlorite producing apparatus, the inner diameter of the riser is 15 mm to 150 mm and the diameter of the small hole is 2 mm to 20 mm.
DETAILED DESCRIPTION OF THE INVENTION
The hypochlorite production apparatus of the present invention is a combination of a gas-liquid separation device and an electrolysis of salt water supplied to an electrolytic cell by connecting a gas-liquid separator to an upper space in an electrolyzer with a gas-liquid mixed fluid. The gas-liquid mixed fluid is raised to the gas-liquid separator by the rise of bubbles that are sometimes generated and separated into hypochlorite and hydrogen in the gas-liquid separator, and when the electrolytic cell is stopped, Since there are no rising bubbles, hypochlorite in the gas-liquid separator flows back into the electrolytic cell, and the hydrogen in the electrolytic cell is discharged to the gas-liquid separator from the small holes provided in the riser pipe for electrolysis. Hydrogen is prevented from staying when the operation of the electrolytic cell is stopped by discharging hydrogen from the inside of the cell.
[0009]
The present invention will be described below with reference to the drawings.
FIG. 1 is a diagram showing an embodiment of the hypochlorite production apparatus of the present invention.
The hypochlorite production apparatus of the present invention has a diaphragm-type electrolytic cell 1, and a gas-liquid separation device 12 coupled to a riser pipe 11 having an opening on the electrolyte surface 10 of the diaphragm-type electrolytic cell 1. Is provided. It has a small hole 13 that opens into an upper space in the electrolytic cell above the diaphragm-type electrolytic cell 1 of the riser 11.
Further, the gas-liquid separator 12 is connected to a hydrogen diffusion pipe 6 and a diluted air supply pipe 14 connected to the dilution air pump 7. In the gas-liquid separator 12, the hypochlorite from which hydrogen has been separated is And stored in a hypochlorite storage tank 8 and supplied to a desired place of use by a supply pump 9.
[0010]
In the hypochlorite production apparatus of the present invention, the saline 2 supplied to the diaphragm-type electrolytic cell 1 is electrolyzed by the anode 15 and the cathode 16, and hypochlorite is generated from the chlorine generated at the anode. Hydrogen is generated by both electrolysis at the cathode and hypochlorite formation reaction.
Due to the buoyancy of the generated hydrogen bubbles 17 and the flow of the supplied salt water, the liquid containing hypochlorite ascends the riser 11 and reaches the gas-liquid separator 12, and the hydrogen bubbles 17 follow. It is separated from the chlorite and discharged from the hydrogen diffusion tube 6. The gas-liquid separator 12 is supplied from an air supply pipe 14 coupled to the dilution air pump 7 and can be diluted to a safe concentration.
Further, when the operation of the diaphragm electrolyzer 1 is stopped, when the supply of the salt water 2 is stopped, hypochlorite flows backward from the gas-liquid separator 12, and the hydrogen in the electrolyzer is a small hole provided in the riser pipe. 13 rises to gas-liquid separator 12 and is discharged to the outside.
[0011]
2 is an enlarged view of a part of FIG. 1, and is an enlarged view of a portion A in FIG.
When the energization to the diaphragm-type electrolytic cell 1 is stopped and the supply of salt water is stopped, the liquid in the gas-liquid separator and the riser pipe 11 flows back into the diaphragm-type electrolytic tank 1 through the riser pipe 11, and the diaphragm membrane The gas in the upper space 18 of the electrolytic cell 1 is discharged to the gas-liquid separator through the small hole 13 through the riser pipe.
In the present invention, any rising pipe can be used, but it is preferable that the rising speed of the liquid passing through the rising pipe and hydrogen bubbles during energization is 0.4 to 0.8 m / sec. If the ascending speed is less than 0.4 m / sec, it is necessary to increase the diameter of the ascending pipe, which is not preferable in terms of structure. On the other hand, if it exceeds 0.8 m / sec, the resistance of the fluid flowing through the riser tube may increase, and the liquid level of the electrolytic cell being energized may change.
[0012]
The inner diameter of the riser is determined according to the amount of hypochlorite produced, but is preferably 15 mm to 150 mm.
Further, the small hole provided in the portion of the riser located in the upper space of the electrolytic cell has a hydrogen flow rate of 15 to 25 m / sec in the small hole portion in order to prevent hydrogen generated during energization from passing through the entire small hole. The diameter is preferably such that 2 mm to 20 mm. Further, the number of small holes is not limited to one, and a plurality of small holes may be provided.
[0013]
【Example】
Hereinafter, the present invention will be described with reference to examples.
Example 1
Electrolytic solution cooling pipes are attached to a diaphragm-type electrolytic cell provided with an anode coated with an electrode catalyst material containing a platinum group metal oxide having a length of 200 mm and a width of 150 mm, and a cathode having a titanium cathode. A gas-liquid separator having a length of 20 mm, a width of 50 mm, and a height of 25 mm is attached to the upper part of the riser pipe having an inner diameter of 40 mm and having an opening on the electrolyte surface of the tank. Was provided.
A current of 250 amperes was passed through the electrolytic cell, and 30 g / l of saline was supplied at a flow rate of 420 liters / hour for electrolysis, and then the current supply and the supply of saline were stopped. The liquid back-flowed into the electrolytic cell from the gas-liquid separator through the riser, and the hydrogen in the upper space in the electrolytic cell was discharged to the gas-liquid separator through the small hole.
[0014]
【The invention's effect】
The hypochlorite production apparatus of the present invention is provided with a gas-liquid separation device coupled to a riser pipe having an opening on the electrolyte surface in a diaphragm-type electrolytic cell, and when the electrolytic cell is stopped, Hydrogen staying in the upper space can be safely released.
[Brief description of the drawings]
FIG. 1 is a diagram showing an embodiment of a hypochlorite production apparatus according to the present invention.
FIG. 2 is a diagram illustrating a part of FIG. 1 in an enlarged manner.
FIG. 3 is a diagram for explaining an example of a conventional hypochlorite production apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Non-membrane type electrolytic cell, 2 ... Saline, 3 ... Hypochlorite pipe, 4 ... Hydrogen pipe, 5 ... Water seal safeguard, 6 ... Hydrogen diffusion pipe, 7 ... Dilution air pump, 8 ... Hypochlorite storage tank, 9 ... supply pump, 10 ... electrolyte surface, 11 ... rising pipe, 12 ... gas-liquid separator, 13 ... small hole, 14 ... lean air supply pipe, 15 ... anode, 16 ... cathode, 17 ... Hydrogen bubbles, 18 ... Upper space

Claims (1)

  In a hypochlorite production apparatus by electrolysis of salt water, a gas-liquid separation device provided at the top of the diaphragm-type electrolytic cell is arranged, and an electrolyte surface is formed in the diaphragm-type electrolytic cell, An upper space is provided in the upper part of the electrolyte surface, and a riser pipe in which one end of the opening is located on the electrolyte solution surface and the other end of the opening is connected to the gas-liquid separation device is arranged. A small hole is provided in the space, and when the operation of the electrolytic cell is stopped, the electrolytic solution in the gas-liquid separation device flows backward through the riser, and the hydrogen remaining in the upper space of the electrolytic cell is separated from the small hole by gas-liquid separation. Hypochlorite production apparatus characterized by discharging to the apparatus.

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