JP3110555B2 - Ion exchange membrane electrolyzer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrolytic cell, and more particularly to an electrolytic cell characterized by gas-liquid separation at an upper portion of an electrode chamber of an electrolytic solution containing bubbles generated by an electrolytic reaction, such as an ion-exchange membrane alkali chloride electrolytic cell. .

[0002]

2. Description of the Related Art An ion exchange membrane filter press type electrolytic cell is widely used for the production of chlorine and caustic soda by electrolysis of saline solution, organic electrolysis, seawater electrolysis and the like. The filter press type electrolytic cell is composed of a large number of bipolar electrolytic cell units in which the partition walls of the anode chamber and the cathode chamber are electrically and mechanically connected via a conductive member or by means such as pressure welding, with a cation exchange membrane interposed therebetween. There is a bipolar filter press type electrolytic cell which is laminated and has an end electrolytic cell unit having either an anode or a cathode on one side and fixed by a hydraulic press or the like, and a frame-shaped electrode chamber frame A single-pole filter in which a large number of anode chamber units and cathode chamber units having an anode or a cathode on both surfaces are laminated via a cation exchange membrane, and an end electrode chamber unit having an anode or a cathode on only one side is laminated on both ends. There is a press type electrolytic cell.

[0003] In an ion exchange membrane method salt electrolyzer, chlorine gas is generated at the anode, and high concentration sodium hydroxide and hydrogen are generated at the cathode, so that a stable passivation film is formed on the surface of the anode chamber in corrosion resistance. In the cathode chamber, an alkali-resistant iron-based metal such as nickel or stainless steel or an alloy thereof is used in place of titanium which absorbs hydrogen and becomes brittle. In each electrode chamber, an anode and a cathode are attached to a conductive rib connected to a partition, and an electrolyte supply nozzle and an electrolyte with a reduced or increased concentration, a gas as a product of an electrolytic reaction, and air bubbles are provided on a side wall. Is provided with a discharge nozzle for the electrolytic solution mixed with.

[0004] As the anode, a perforated plate such as titanium, an expanded metal or the like as a base material, the surface of which is coated with an oxide of a platinum group metal such as ruthenium, iridium or palladium is used. As the cathode, there is used a cathode whose base material is a porous plate of iron, stainless steel, nickel or the like, expanded metal, or the like, and whose surface is coated with a cathode catalyst material such as a nickel-based or platinum group metal-based. As the ion exchange membrane, a fluorinated resin-based cation exchange membrane having a sulfonic acid group, a carboxylic acid group and the like is used.

[0005]

In an electrolytic cell of a filter press type ion-exchange membrane method, when an electrolysis reaction such as electrolysis of salt is performed to generate a gas, an anolyte or a catholyte containing bubbles is converted into an electrode chamber. When the air is extracted from the electrode, the pressure in the electrode chamber fluctuates due to the bubbles. The anolyte or catholyte in the electrode chamber of a commonly used vertical alkaline chloride electrolyzer increases the bubble rate, which is the proportion of bubbles toward the top, due to bubbles generated at the electrode, and becomes closer to the upper layer of the electrode chamber liquid. The bubbles are aggregated to form a foam layer, and a gas phase is formed at the uppermost portion from the gas separated from the foam. As a result, when trying to discharge the electrolyte and generated gas from the upper part of the electrode chamber, the outflow state is a gas-liquid mixed phase, a bubble flow in which the liquid phase and the gas phase are mixed,
A complicated flow that fluctuates the pressure in the electrode chamber due to a plug flow, a wavy flow, or the like that closes the conduit is generated. In particular, chlorine bubbles formed on the anode chamber side are less likely to disappear than hydrogen bubbles formed from caustic soda and hydrogen on the cathode chamber side due to salt water viscosity, surface tension, etc. cause. Therefore, pressure fluctuation in the anode compartment may vary depending electrolysis conditions 50~200mmH ₂ O, exceed 300mmH ₂ O is optionally repeated to leave out of contact with the electrode surface by constantly vibrate the ion exchange membrane, cation The surface of the ion exchange membrane is scratched by friction, and the cation exchange membrane is cracked due to fatigue due to vibration. As a result, the characteristics of the cation exchange membrane are degraded, and the electrode is generally damaged by alkali flowing into the anode chamber from the cathode chamber where the pressure in the electrode chamber is high, which adversely affects the life of the electrode.

Therefore, in a saline ion-exchange membrane electrolytic cell, a method for keeping the pressure of the cathode chamber larger than the maximum fluctuation of the anode chamber pressure and constantly pressing the membrane against the anode surface to prevent vibration is provided. A method in which a chamber higher than the level of the electrolyte is provided at the upper part, a gas-liquid separation zone is formed in the chamber, and the bubbles are spontaneously defoamed in the chamber and taken out as a wavy flow or a stratified flow from the discharge nozzle on the side wall. 30 mm from the inner surface of the electrode chamber upper wall as shown in
When the liquid flow rate in the nozzle is 0.5 to 2
A method of providing a nozzle having a speed of 0 m / sec has been proposed.

However, in the method of applying a pressure larger than the maximum value of the pressure fluctuation of the anode chamber to the cathode chamber, the membrane always excessively presses the anode surface made of expanded metal or a perforated plate and cuts into the opening of the anode. Therefore, not only the anode overvoltage of chlorine generation is increased and the electrolytic cell voltage is increased by several to several tens of mV to cause power loss, but also in the long term, the erosion of the catalytically active coating of the anode due to alkali reversely migrating from the cathode side. However, there is a disadvantage that the life of the electrode is shortened largely as compared with the case where the pressure of the cathode pressurization is small.

A method of providing a gas-liquid separation zone by raising the upper part of the electrode chamber is effective in preventing pressure fluctuation, but may increase the material cost and the processing cost due to the increase in the capacity of the electrode chamber. Furthermore, the method of inserting the discharge nozzle from the upper wall surface of the electrode chamber requires the operation of the electrolytic cell because it is necessary to determine the size of the discharge nozzle according to the ratio of the amount of generated gas and the circulation amount of the electrolyte in the electrode chamber. In the case of a bipolar electrolytic cell, it is necessary to take measures to prevent corrosion due to leak current flowing through the discharge nozzle.

Further, in the method using the discharge nozzle, the surface of the ion exchange membrane above the electrode chamber is in a dry state, and the gaseous chlorine permeating the cation exchange membrane adversely affects the cation exchange membrane. It has been clarified that it is necessary to provide, by welding or the like, a weir for overflowing the electrolyte in order to keep the surface of the cation exchange membrane in a wet state on the upper partition wall surface (see "Soda and Chlorine" Vol. 41). No. 4, page 18 (April 1990)).

On the other hand, a method of manufacturing a pot-shaped electrode chamber of a bipolar electrolytic cell by using a thin plate made of titanium, nickel, stainless steel or the like by a die press is easy to manufacture and has high mass productivity. This is a preferable manufacturing method because it is extremely effective in reducing the cost of the electrolytic cell. However, adding a gas-liquid separation chamber or attaching a weir or the like by welding loses the characteristics of press molding.

[0011]

SUMMARY OF THE INVENTION The inventor of the present invention does not apply welding work to an electrode chamber partition formed by a die press using a thin plate made of titanium, nickel, stainless steel or the like, which has a simple structure and can reduce the manufacturing cost. The present invention has been made as a result of intensive pursuit of means for separating gas and liquid in the electrolytic reaction region above the electrode chamber to reduce pressure fluctuation in the electrode chamber and to prevent vibration of the cation exchange membrane.

The electrolytic cell of the present invention has, at the upper part of the electrode chamber, a conduit whose one end is closed and whose upper surface is open in a U-shaped cross section.
A rectangular orifice-shaped gap is formed between the electrode side of the conduit and the upper wall surface, and a space formed between the partition and the conduit is formed on the upper side surface of the electrode chamber of the conduit on the partition side. The other end of the conduit is an electrolytic cell connected to a nozzle provided on the side wall of the electrolytic cell.

That is, since the upper end of the electrode chamber is provided with a conduit whose one end is closed and has a U-shaped cross section and the upper surface is open, the upper space of the electrode chamber is narrowed. The passage narrows, and the air bubbles contact and expand, and are compressed from a narrow gap formed between the upper wall surface of the electrode chamber and the side wall of the conduit and flow into the conduit. During the inflow, many of the bubbles burst due to the change in compression and pressure, and the electrolyte and gas containing bubbles remaining in the pipe flow toward the discharge nozzle. Further, when air bubbles are clogged with foam in the pipeline, the gas flows into the space formed between the U-shaped pipeline and the partition wall by the communication passage provided on the side wall of the pipeline and is bypassed to the discharge nozzle. It is like that.

Hereinafter, the present invention will be described in more detail with reference to the drawings. FIG. 1 is a plan view of a bipolar electrode unit with a part cut away, and FIG. 2 is a cross-sectional view of FIG. 1 taken along line AA. The bipolar cell unit 1 has an anode chamber 3 and a cathode chamber 4 formed on the left and right with a frame frame 2 formed of a rigid body such as carbon steel as a skeleton. The partition wall 5 on the side of the anode chamber, which has been processed into a shape, and the partition wall 6 on the side of the cathode chamber, which is also made of a thin plate made of iron, stainless steel, nickel or the like, are electrically and mechanically connected by a connecting portion 7. In the anode chamber and the cathode chamber, an anode 10 having a coating containing a platinum group metal or oxide formed on conductive ribs 8 and 9 bonded to a partition wall respectively, and a cathode having a nickel or platinum group cathode active material coated thereon 11 are attached, and U-shaped conduits 12, 13 are provided at the upper part of the electrode chamber.
Is provided. The U-shaped conduit is attached with an interval between the electrode and the partition wall, and between the side wall 14 on the electrode surface side of the U-shaped conduit and the upper wall 15 of the electrode chamber, the raised electrolytic solution and bubbles flow. A narrow gap 16 is formed,
A communication path 17 is provided on the wall surface of the U-shaped pipe on the partition wall side.

One end of the U-shaped conduit is connected to a discharge nozzle 19 attached to the side wall 18 of the electrolytic cell unit for taking out the electrolytic solution and gas to the outside. The nozzle 20 is attached, and a mounting arm for attaching the electrolytic cell unit to the gantry is provided on a side wall of the electrolytic cell unit.

FIG. 3 shows a view in which a U-shaped pipe is attached from the electrolyte discharge nozzle to the inside of the electrolytic cell. The U-shaped pipe 1 is connected to the discharge nozzle 19 provided on the side wall 18 of the electrolytic cell unit.
2, 13 are attached. For the U-shaped conduit, it is preferable to use a synthetic resin such as a fluororesin or polypropylene in order to prevent electrolytic corrosion in the electrolytic cell. The U-shaped pipe is attached to the discharge nozzle 19 via a gasket 21,
A cut-out portion 22 serving as a guide for a U-shaped conduit is formed in the conductive rib 8 for attaching an electrode. A communication passage 17 is provided on a side wall of the U-shaped pipe.

FIG. 4 is a diagram showing a bipolar electrolytic cell.
Five bipolar electrode unit 1 and end anode unit 2
3 and an end cathode unit 24. A cation exchange membrane 25 is attached between the electrolytic cell units, placed on a gantry 26, and fixed by a hydraulic press, a tie rod, or the like. Discharge nozzle 1 on unit side wall
9. A pipeline is connected to the supply nozzle 20 to supply an electrolytic current to the electrolytic cell units at both ends.

FIG. 5 is a view for explaining the flow of the electrolytic solution to the U-shaped pipe provided in the electrolytic cell of the present invention. The U-shaped conduit equalizes the upward flow of the electrolyte in a gas-liquid mixed phase over the entire electrode chamber, and has a liquid surface 28 in the partition-side space 27 of the electrode chamber.
And a height corresponding to the length between both side walls of the electrode chamber is required to form the gas bypass channel. In addition, the height of the side wall of the U-shaped conduit needs to be a distance that promotes coalescence of bubbles in the rising path of the electrolytic solution on the electrode side, that is, a height, and the current density is 3 kA / m ² , the temperature is 85 ° C., The results obtained by experiments under standard electrolysis conditions of a concentration of 200 g / l have revealed that 4% or more, preferably 5% or more, of the liquid surface depth of the electrolytic cell is required.

The electrolytic space 29 of the anode chamber is a region in which chlorine bubbles are freely rising in the salt solution of the electrolyte while receiving complicated fluid resistance, but the rising flow is separated by a U-shaped conduit. When reaching the portion, most of the bubbles enter the flow path of the electrode-side space 30 and rise together with the liquid, whereas the partition-side space 27
The liquid surface 28 is formed without any rise in gas-liquid. In order to form the liquid surface 28 in the partition-side space and to form an upward flow in the electrode-side space, it is necessary that the space on the electrode side be at least twice as large as the space on the partition-side. Is preferably as small as possible without causing capillary action, and more preferably 2 to 4 mm. Also, as shown in FIG. 5, a difference is formed between the liquid levels on both sides of the U-shaped conduit.

This is because, in the electrode chamber, the generated gas bubbles rise mainly on the electrode side, so that a difference occurs between the density of the electrolyte in the region on the partition wall side and the density on the electrode side. This is because the liquid surface of the space formed between the partition wall and the partition wall is formed on the electrode side of the U-shaped conduit. The width of the U-shaped conduit must be such that a gas-liquid flow rate commensurate with the supply amount of the electrolyte and the amount of gas generated flows into the conduit, and the cross-sectional area of the flow passage necessary to move the discharge nozzle without confusion is required. , And preferably 10 mm or more. Also, as the height of the U-shaped conduit increases, the flow area of the electrolytic solution increases, but the current distribution to the upper end of the electrode through the conductive rib may be insufficient.
It is preferable that the height of the mold pipe be 60 to 100 mm. In particular, in the electrolytic cell of the present invention, a gas-phase space is provided between the U-shaped pipe and the partition wall to form a bypass for generated gas, so that the width of the U-shaped pipe can be reduced.

Further, the gas-liquid multiphase flow that has risen in the electrode side space reaches the upper wall surface of the electrode chamber, and the gas flows from the gap formed by the upper wall surface of the electrode chamber and the upper side wall of the U-shaped conduit on the electrode side. While flowing into the type pipe and passing through the gap, many bubbles burst, and the electrolyte containing the foam is taken out into the U-type pipe and from the U-type pipe to the outside through the discharge nozzle. The gap formed between the side wall of the U-shaped conduit and the upper wall of the electrode chamber is 3
If the gap is large, it is not preferable because the flow path resistance increases, and conversely, the pressure fluctuation increases. The fluctuation is undesirably large.

[0022]

In the electrolytic cell of the present invention, a conduit having a U-shaped cross section with one end closed at the top of the electrode chamber is provided at an interval from the partition and the electrode, and the gap between the electrode and the electrode is reduced. Since the flow path of the electrolytic solution containing the gas and the space between the partition walls are used as the gas bypass flow path, the bubbles in the upper part of the electrode chamber are united and expanded in the narrow flow path of the electrode and the conduit, and the upper wall surface of the electrode chamber is formed. The gas flows into the pipe through a narrow gap formed between the pipe and a side wall of the pipe, and most of the gas bursts and undergoes gas-liquid separation due to a change in pressure of compression and expansion during the flow. Also, in the flow of the electrolyte and gas containing foam flowing toward the discharge nozzle in the pipe, when the foam blocks the gas and the pressure increases, the partition wall is formed from the communication passage formed on the partition side of the pipe. Since the gas can flow out into the space formed between the electrodes and the change in the pressure in the electrode chamber can be reduced, it is possible to prevent adverse effects due to the vibration of the cation exchange membrane.

[0023]

【Example】

Example 1 A titanium plate having a thickness of 1 mm and a stainless steel plate were formed into a 140 mm long × 93.5 cm wide × 3 cm deep anode chamber and a cathode chamber by a press die, and a notch for fixing a U-shaped conduit thereto. 4 mm thick, 3 cm wide, 13 long with
Five conductive ribs of 0 cm titanium and stainless steel were attached by welding at an interval of 18 cm from the center of the width of the electrode chamber, and an electrolyte supply nozzle was formed below the side walls of both electrode chambers as an electrolyte solution supply nozzle using the same material as the electrode chamber with an inner diameter of 13 mm and an outer diameter of 17. 3mm, length 100mm
A short pipe with a flange is attached, and a flanged square pipe of the same material as the electrode chamber and having a thickness of 1.5 mm, 6.5 cm x 3 cm x 10 cm, is attached as a discharge nozzle for the electrolytic solution and the gas produced by the electrolysis. Was. Next, a frame-like frame, an anode chamber and a cathode chamber were mounted on a cladding body of titanium and copper attached to the anode chamber side and a partition on the cathode chamber side as disclosed in JP-A-3-24.
As described in Japanese Patent No. 0984, brazing was performed in an electric furnace using solder to join the partition walls of both electrode chambers and to integrate the frame-shaped frame.

Thereafter, an expanded metal having an aperture ratio of 35% obtained from a titanium plate having a thickness of 1 mm and having an anode active coating containing a noble metal oxide, having a length of 1.399 m, was obtained.
× 0.933 m width Electrode effective area 1.3 m ² anode (manufactured by Permelec Electrode Co., Ltd.) and expanded metal with a 37% aperture ratio obtained from a 1.5 mm thick stainless steel plate coated with a nickel-based active cathode And a cathode having the same dimensions as the anode was spot-welded to the conductive rib to produce a bipolar electrolytic cell unit.

The anode chamber and the cathode chamber each form a single end anode unit and a single end cathode unit. Three double-electrode type electrolytic cell units are provided with corrosion-resistant gaskets on the flange surface. An anode unit and an end cathode unit were provided, and an ion exchange membrane was sandwiched and laminated. The distance between the electrodes was 2 mm, and Nafion N9 was used as a cation exchange membrane.
A bipolar electrolytic cell having four 54 (trade name of DuPont) was assembled.

Next, a fluororesin thickness 1.5 mm,
A U-shaped conduit having a height of 57 mm, a width of 18 mm, a total length of 1025 mm, an upper opening length of 93 mm, and having three 5 mm holes on the side wall of the partition wall, the upper wall surface of the electrode chamber and the side wall of the U-shaped conduit Is 5 mm, and the distance from the electrode surface is 8 m.
m, and the distance between the partition and the partition was 4 mm, and was connected to the discharge nozzle.

Each nozzle is connected to a main pipe for supplying an electrolytic solution and a main pipe for discharging an electrolytic solution and a generated gas through a flexible tube made of a fluororesin.
The electrolytic cell was completed by connecting to a cathode terminal. Pure water is supplied to the cathode compartment, 300 g / l of saline is supplied to the anode compartment, 32% caustic soda is supplied from the cathode compartment, and 200 g / l of saline solution is returned from the anode compartment. Take out, electrolytic cell temperature 85 ° C, electrolytic current 5.2 kA, current density 3 kA
/ M ² and operated for 30 days. During this period, the generated current efficiency of caustic soda was 96.2%, the average cell voltage of the four pairs of electrolytic cell units was 3.05 V, and the pressure fluctuation in the anode chamber was 15%.
The state was extremely stable within mmH ₂ O.

Then, the current density is set to 4 kA / m ² , and the supply amount of the salt water is returned to circulate the salt water to confirm the pressure fluctuation under the high load electrolysis conditions.
The anode chamber pressure fluctuation was measured by increasing the amount twice, and the results are shown in Table 1.
Shown in In addition, the operation of the electrolytic cell was stopped, and the cation exchange membrane was inspected, but no abnormality such as discoloration or deterioration was found.

Example 2 The same procedure as in Example 1 was carried out except that a U-shaped pipe having a distance of 10 mm between the side wall on the electrode side of the U-shaped pipe of Example 1 and the upper wall of the anode chamber was attached. After operating for 15 days under the conditions, the current efficiency was 95.6%, the average cell voltage was 3.06 V,
The initial electrolysis performance was almost the same as in Example 1. The fluctuation of the anode chamber pressure was measured in the same manner as in Example 1, and the results are shown in Table 1. After the operation was stopped, discoloration with a width of about 5 mm was observed on the upper portion of the cation exchange membrane. Example 3 The same conditions as in Example 1 were adopted, except that a U-shaped conduit having a distance of 15 mm between the electrode side wall of the U-shaped conduit of Example 1 and the upper wall surface of the anode chamber was attached. As a result of operating for a day, the current efficiency was 95.2%, the average cell voltage was 3.09 V,
The initial electrolysis performance was almost the same as in Example 1. The fluctuation of the anode chamber pressure was measured in the same manner as in Example 1, and the results are shown in Table 1. Further, after the operation was stopped, the discoloration of the upper part of the cation exchange membrane which was considered to be caused by chlorine having a width of about 10 mm was observed.

[0030]

[Table 1]

Comparative Example 1 The U-shaped conduit was removed from the electrolytic cell of Example 2, and the electrolytic cell was reassembled using the cation exchange membrane used in Example 2 under the same conditions as in Example 2. I drove for 15 days. The current efficiency was 94.8%, the average cell voltage was 3.11 V, and a decrease in electrolytic performance was observed. The pressure in the anode chamber is -10 to 120
The value constantly fluctuated in the range of mmH ₂ O and was larger than that in Example 2. A plug flow occurred in the discharge nozzle, and an intermittent outflow phenomenon was observed.

When the cation exchange membrane was inspected after the operation was stopped, a brown discoloration with a width of about 100 mm was observed at the upper portion of the cation exchange membrane, and the discoloration changed to 35 mm below the lower side of the discharge nozzle and a small blister having a diameter of about 2 mm. Were scattered, and blackish brown discoloration and abrasions which appeared to have touched the file-like active cathode surface were partially observed.

COMPARATIVE EXAMPLE 2 Instead of a U-shaped conduit, the distance between the upper end of an L-shaped member having a height of 57 mm and a width of 18 mm and the upper wall of the electrode chamber was 5 mm, and the distance between the electrodes was 8 mm. After welding and mounting, the discharge nozzle on the side wall of the electrode chamber was modified, a discharge nozzle with an inner diameter of 25 mm x an outer diameter of 27.2 mm was provided at the bottom of the cabinet, the electrode was restored, and the electrode was assembled into the electrolytic cell. It was operated for 15 days under the same standard electrolysis conditions.

The current efficiency is 95.8% and the cell voltage is 3.08.
It was V. The electrode chamber pressure greatly fluctuated in the range of −20 to 180 mmH ₂ O, and the gas / liquid outflow state from the discharge nozzle was a typical intermittent plug flow. The pressure fluctuation under the conditions where the current density and the circulation magnification were changed to 4 kA / m ² and 3 times, respectively, increased to −40 to ₂₀₀ mmH ₂ O. At the top of the opened membrane, a black-brown change was seen, which appeared to have touched the active cathode.

[0035]

As described above, the electrolytic cell of the present invention takes out and discharges the mixed fluid of the electrolytic solution and the generated gas instead of the other pressure fluctuation suppressing method constituted by directly welding the electrode chamber partition and the like. With a simple means of inserting a U-shaped conduit from the nozzle, fluctuations in the pressure in the electrode chamber and vibrations of the ion exchange membrane due to this can be prevented, and the life of the ion exchange membrane and the electrode can be extended. Also, if a member made of a synthetic resin is used as the U-shaped conduit, the leakage current can be reduced.

[Brief description of the drawings]

FIG. 1 is a plan view, partially cut away, of a bipolar electrolytic cell unit showing one embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA in FIG.

FIG. 3 is a diagram illustrating attachment of a U-shaped conduit from the side wall of the electrolytic cell unit to the inside of the electrolytic cell.

FIG. 4 is a diagram showing a bipolar electrolytic cell.

FIG. 5 is a diagram illustrating a flow of an electrolytic solution to a U-shaped pipe provided in the electrolytic cell of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Electrolyzer unit, 2 ... Frame-shaped frame, 3 ... Anode room, 4 ... Cathode room, 5 ... Anode room side partition, 6 ... Cathode room side partition, 7 ... Connection part, 8, 9 ... Conductive rib, 10 ... Anode, 1
DESCRIPTION OF SYMBOLS 1 ... Cathode, 12, 13 ... U-shaped conduit, 14 ... Side wall on the electrode surface side of U-shaped conduit, 15 ... Upper wall of electrode chamber, 16 ... Gap, 1
7 ... communication passage, 18 ... side wall, 19 ... discharge nozzle, 20 ...
Supply nozzle, 21 gasket, 22 notch, 2
3 ... End anode unit, 24 ... End cathode unit, 25
... Cation exchange membrane, 26 ... Stand, 27 ... Partition side space, 2
8: liquid level, 29: electrolytic space part, 30: electrode side space

Claims (2)

(57) [Claims] 1. An ion-exchange membrane electrolytic cell having a U-shaped pipe having a U-shaped upper surface opened at the upper part of the electrolytic cell, wherein a side wall of the U-shaped pipe and an upper wall surface of the U-shaped pipe are connected to each other. A gap is formed between the gap and the gap communicating with the gap formed on the outer surface of the side wall of the U-shaped pipe, and the gas-liquid mixture generated in the electrode chamber is formed with the gap formed on the outer surface of the side wall of the U-shaped pipe. An ion-exchange membrane electrolytic cell, wherein gas-liquid separation is performed by introducing gas into a U-shaped pipe through a gap formed between a side wall of the U-shaped pipe and an upper wall surface of the U-shaped pipe. 2. A communication path with a space formed between the partition wall and the conduit is provided on the upper side surface of the electrode chamber of the U-shaped conduit on the partition wall side, and the other end of the conduit is connected to the electrolytic cell. The ion exchange membrane electrolytic cell according to claim 1, wherein the ion exchange membrane electrolytic cell is connected to a nozzle provided on a side wall portion.