TW202136584A - Fluorine gas production method and fluorine gas production apparatus - Google Patents

Abstract

Provided is a fluorine gas production method whereby it becomes possible to prevent the clogging of a pipe or a valve by mists. A fluorine gas is produced by a method comprising: an electrolysis step of carrying out the electrolysis of an electrolyte solution in an electrolysis tank; a water concentration measurement step of measuring the water concentration in the electrolyte solution at a time point of the electrolysis; and a gas feeding step of feeding a fluid generated in the electrolysis tank upon the electrolysis of the electrolyte solution from the inside of the electrolysis tank to the outside of the electrolysis tank through a flow passage. In the gas feeding step, a flow passage through which the fluid is to be flown is switched to another one depending on the water concentration in the electrolyte solution which is measured in the water concentration measurement step, in such a manner that the fluid is fed to a first flow passage through which the fluid can be fed from the inside of the electrolysis tank to a first outside zone when the water concentration in the electrolyte solution which is measured in the water concentration measurement step is equal to or less than a preset reference value, while the fluid is fed to a second flow passage through which the fluid can be fed from the inside of the electrolysis tank to a second outside zone when the water concentration is larger than the preset reference value. The preset reference value is a numerical value falling within the range of 0.1 to 0.8% by mass inclusive.

Description

Fluorine gas production method and fluorine gas production device

The present invention relates to a fluorine gas production method and a fluorine gas production device.

The fluorine gas system can be synthesized by electrolyzing an electrolyte containing hydrogen fluoride and metal fluoride (electrolytic synthesis). Through the electrolysis of the electrolyte, the fluorine gas also produces mist (for example, the mist of the electrolyte), so the fluorine gas sent from the electrolytic cell is mixed with the mist. The mist mixed with the fluorine gas becomes a powder, and there is a concern that the piping or valve used for the fluorine gas supply will be blocked. For this reason, it may be necessary to interrupt or stop the operation of producing fluorine gas, which will hinder the continuous operation of the production of fluorine gas produced by the electrolysis method. In order to suppress the clogging of pipes or valves caused by the mist, Patent Document 1 discloses a technique of heating the fluorine gas mixed with the mist or the pipe through which the gas passes to a temperature above the melting point of the electrolyte. In addition, Patent Document 2 discloses a gas generating device having a gas diffuser having a space for roughening mist and a filling material accommodating part accommodating a filling material for absorbing the mist. [Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Publication No. 5584904 [Patent Document 2] Japanese Patent Publication No. 5919824

[The problem to be solved by the invention]

However, it is more desirable to have a technology that more effectively suppresses the clogging of pipes or valves caused by mist. The subject of the present invention is to provide a fluorine gas manufacturing method and a fluorine gas manufacturing device that can suppress the clogging of pipes or valves caused by mist. [Means to solve the problem]

In order to solve the aforementioned problems, one aspect of the present invention is as follows [1] to [5]. [1] In the method of producing fluorine gas by electrolyzing an electrolyte containing hydrogen fluoride and metal fluoride to produce fluorine gas, Possess: In the electrolytic cell, carry out the electrolysis process of the aforementioned electrolysis, And during the aforementioned electrolysis, the water concentration measurement process to measure the water concentration in the aforementioned electrolyte, And during the electrolysis of the aforementioned electrolyte, the fluid generated inside the aforementioned electrolytic cell is transported from the inside of the aforementioned electrolytic cell to the outside flow channel through the gas supply process; In the aforementioned gas supply project, corresponding to the water concentration in the electrolyte measured by the aforementioned water concentration measurement project, the flow channel through which the fluid flows is switched, and the water concentration in the aforementioned electrolyte measured by the aforementioned water concentration measurement project is a preset reference When the value is less than or equal to the value below, in the first flow path that transports the fluid from the inside of the electrolytic cell to the first outside, and when the fluid is transported, the fluid is transported from the inside of the electrolytic cell to the first 2 The second flow channel for externally transporting the aforementioned fluid, transporting the aforementioned fluid, The aforementioned preset reference value is a method for producing fluorine gas with a value in the range of 0.1% by mass to 0.8% by mass.

[2] The aforementioned metal fluoride is a fluoride of at least one metal selected from potassium, cesium, rubidium, and lithium. The method for producing fluorine gas described in [1]. [3] The anode used in the foregoing electrolysis is a carbon electrode formed of at least one carbon material selected from diamond, diamond-like carbon, amorphous carbon, graphite, and glassy carbon, as described in [1] or [2 ] The manufacturing method of fluorine gas. [4] The structure that the bubble generated by the anode or cathode used in the electrolysis in the electrolysis cell rises in the vertical direction in the electrolytic solution and can reach the liquid surface of the electrolytic solution is described in [1]~[ 3] Any one of the manufacturing methods of fluorine gas.

[5] In a fluorine gas production device that electrolyzes an electrolyte containing hydrogen fluoride and metal fluoride to produce fluorine gas, Equipped with: an electrolytic cell for accommodating the aforementioned electrolyte and performing the aforementioned electrolysis, And during the aforementioned electrolysis, the water concentration measuring part that measures the water concentration in the electrolyte in the aforementioned electrolytic cell, And during the electrolysis of the foregoing electrolyte, the fluid generated in the interior of the foregoing electrolytic tank is transported from the interior of the foregoing electrolytic tank to the outside; The flow channel has a first flow channel that transports the fluid from the inside of the electrolytic cell to the first outside, and a second flow channel that transports the fluid from the inside of the electrolytic cell to the second outside, and has a corresponding The water concentration in the electrolyte measured by the water concentration measuring unit switches the flow path through which the fluid flows to the first flow path or the second flow path. The flow path switching unit transports the fluid from the inside of the electrolytic cell to the first flow path when the water concentration in the electrolyte measured by the water concentration measurement unit is below a preset reference value. When the predetermined reference value is large, the fluid is fed from the inside of the electrolytic cell to the second flow path, The aforementioned preset reference value is a fluorine gas production device with a value in the range of 0.1% by mass to 0.8% by mass. [Effects of the invention]

According to the present invention, the electrolytic solution containing hydrogen fluoride and metal fluoride is electrolyzed, and when fluorine gas is produced, the clogging of pipes or valves caused by mist can be suppressed.

The description of one embodiment of the present invention is as follows. However, this embodiment shows an example of the embodiment, but the present invention is not limited to this embodiment. In addition, in this embodiment, various changes or improvements can be added, and the form adding these changes or improvements is also included in this invention. In the electrolytic synthesis of fluorine gas, the inventors conducted an in-depth review of the mist that caused the blockage of pipes or valves. The "mist" in the present invention refers to liquid particles or solid particles produced when fluorine gas is generated in the electrolytic cell through the electrolysis of the electrolyte. Specifically, it refers to the reaction of the particles of the electrolyte, the particles of the solid in which the particles of the electrolyte phase change, and the components that constitute the electrolytic cell (the metal forming the electrolytic cell, the gasket for the electrolytic cell, the carbon electrode, etc.) react with the fluorine gas The resulting solid particles.

The inventors of the present invention measured the average particle diameter of the mist contained in the fluid generated inside the electrolytic cell during the electrolysis of the electrolyte, and confirmed that the average particle diameter of the mist changes over time. In addition, after in-depth review, it is found that the average particle diameter of the mist is related to the water concentration in the electrolyte during electrolysis, and it is also found that the average particle diameter of the mist and the occlusion of the pipe or valve of the conveying fluid are easy to occur. There is a correlation between sex. Then, it was discovered that it corresponds to the concentration of water in the electrolyte during electrolysis, improved the flow channel for conveying the fluid generated inside the electrolytic cell, suppressed the blockage of the pipe or valve, and reduced the frequency of interruption or stop of the operation of producing fluorine gas. So as to complete the present invention. The description of one embodiment of the present invention is as follows.

The method for producing fluorine gas in this embodiment is to electrolyze an electrolyte containing hydrogen fluoride and metal fluoride. The method for producing fluorine gas for producing fluorine gas includes an electrolysis process for electrolysis in an electrolytic cell, and measurement during electrolysis. The water concentration measurement process of the water concentration in the electrolyte, and the fluid generated inside the electrolytic cell during the electrolysis of the electrolyte, is a gas supply process that transports the fluid generated inside the electrolytic cell from the inside of the electrolytic cell to the outside of the flow channel.

In the gas supply process, it becomes the channel of the flowing fluid that corresponds to the water concentration in the electrolyte measured by the water concentration measurement process. That is, when the water concentration in the electrolyte measured by the water concentration measurement process is less than the preset reference value, the first flow channel that transports the fluid from the inside of the electrolytic cell to the first outside will transport the fluid more than before. When the set reference value is large, the fluid is transported in the second flow path that transports fluid from the inside of the electrolytic cell to the second outside. Then, the preset reference value is a value within the range of 0.1% by mass to 0.8% by mass.

In addition, the fluorine gas production device of this embodiment electrolyzes an electrolyte containing hydrogen fluoride and metal fluoride. The fluorine gas production device for producing fluorine gas is equipped with an electrolytic cell that contains the electrolyte and performs electrolysis, and during electrolysis, The water concentration measuring section for measuring the water concentration in the electrolyte in the electrolytic cell and the flow channel that transports the fluid generated inside the electrolytic cell from the inside of the electrolytic cell to the outside during the electrolysis of the electrolyte.

The flow channel has a first flow channel that transports fluid from the inside of the electrolytic cell to the first outside, and a second flow channel that transports fluid from the inside of the electrolytic cell to the second outside. In addition, this flow channel has a flow channel switching section that switches the flow channel of the flowing fluid to the first flow channel or the second flow channel in accordance with the moisture concentration in the electrolyte measured by the moisture concentration measurement section. The flow channel switching section is to transport fluid from the inside of the electrolytic cell to the first flow channel when the moisture concentration in the electrolyte measured by the moisture concentration measurement section is below the preset reference value, which is lower than the preset reference value When it is large, the fluid is sent from the inside of the electrolytic cell to the second flow channel. Then, the preset reference value is a value within the range of 0.1% by mass to 0.8% by mass.

In the fluorine gas production method and fluorine gas production apparatus of this embodiment, the flow channel of the flowing fluid is switched to the first flow channel or the second flow channel according to the water concentration in the electrolyte during electrolysis. As a result, the average particle diameter corresponding to the mist is obtained, and the flow channel is switched to the first flow channel or the second flow channel, and it is difficult to generate the flow channel blockage caused by the mist. For this reason, the fluorine gas production method and the fluorine gas production device of this embodiment electrolyze an electrolyte containing hydrogen fluoride and metal fluoride, and when producing fluorine gas, it is possible to suppress the clogging of pipes or valves caused by mist. Therefore, the frequency of interruption or stop of the fluorine gas production operation can be reduced, and continuous operation can be easily performed. For this reason, fluorine gas can be produced economically.

However, in the fluorine gas production method and fluorine gas production apparatus of this embodiment, the measurement of the water concentration in the electrolyte may be performed on the electrolyte in the anode chamber with anode, and it may be performed on the cathode chamber with cathode. Electrolyte can also be carried out. In addition, the measurement of the water concentration in the electrolyte may be carried out frequently during electrolysis, may be carried out regularly at regular intervals, or may be carried out at any time from time to time. Furthermore, although the first flow channel and the second flow channel are separate flow channels, the first outer and second outer systems may be separate locations or the same location.

Here, an example of the fluorine gas production method and fluorine gas production apparatus of this embodiment is shown. The first flow path is a flow path for conveying fluid through the mist removal part that removes mist from the fluid from the inside of the electrolytic cell to the fluorine gas extraction part where the fluorine gas is extracted from the fluid. The second flow path is a flow path that conveys fluid from the inside of the electrolytic cell to the fluorine gas extraction part without passing through the mist removal part. That is, when the moisture concentration in the electrolyte is below the preset reference value, the fluid is sent to the mist removal part provided in the first flow channel, and when the fluid system is larger than the preset reference value, the flow system will not be sent to the mist. Remove the department. In this example, the fluorine gas extraction part corresponds to the first exterior and the second exterior. Although the first exterior and the second exterior are the same place, the first exterior and the second exterior may be separate locations.

Then, the second flow path has an occlusion suppression mechanism that suppresses the occlusion of the second flow path caused by mist. The occlusion suppression mechanism is not particularly limited as long as it can suppress the occlusion of the second flow path caused by mist, but for example, the following may be mentioned. That is, large-diameter pipes, inclined pipes, rotating spirals, and air flow generators can be exemplified, and these can be used in combination. In detail, at least a part of the second flow channel is configured by a pipe having a larger diameter than the first flow channel, so that the blockage of the second flow channel caused by mist can be suppressed. In addition, at least a part of the second flow path is formed by piping that is inclined to the horizontal direction and extends in a direction descending from the upstream side to the downstream side, so that the obstruction of the second flow path due to mist can be suppressed.

Moreover, the mist accumulated in the second flow channel is transported to the upstream or downstream side of the rotating spiral, which is arranged inside the second flow channel, and the blockage of the second flow channel caused by the mist can be suppressed. Furthermore, the airflow generating device that circulates the airflow that increases the flow velocity of the fluid flowing in the second flow channel is installed in the second flow channel, so that the blockage of the second flow channel caused by the mist can be suppressed. However, a mist removal part different from the mist removal part provided in the first flow path may be provided as the occlusion suppression mechanism in the second flow path.

Since the first flow channel removes mist from the fluid through the mist removal part, it is difficult to generate occlusion due to mist, and the second flow channel is provided with an occlusion suppression mechanism, so it is difficult to generate occlusion due to mist. For this reason, the fluorine gas production method and the fluorine gas production device of this embodiment electrolyze an electrolyte containing hydrogen fluoride and metal fluoride, and when producing fluorine gas, it is possible to suppress the clogging of pipes or valves caused by mist. However, even if there is no mist removal unit or occlusion suppression mechanism, only by switching the flow path of the flowing fluid to another flow path (the first flow path or the second flow path), it can play a role in suppressing the piping or valve caused by the mist. The occlusion effect is excellent in the above-mentioned effect if it is equipped with a mist removal part or an occlusion suppression mechanism.

Hereinafter, the fluorine gas production method and the fluorine gas production apparatus of this embodiment will be described in more detail. [Electrolyzer] The shape of the electrolytic cell is not particularly limited, as long as the electrolytic solution containing hydrogen fluoride and metal fluoride can be electrolyzed to generate fluorine gas, any electrolytic cell can be used. Usually, the inside of the electrolytic cell is divided into an anode chamber with an anode and a cathode chamber with a cathode by partition members such as partition walls, so that the fluorine gas produced by the anode and the hydrogen gas produced by the cathode will not be mixed.

As the anode system, for example, carbon electrodes formed of carbon materials such as diamond, diamond-like carbon, amorphous carbon, graphite, glassy carbon, and amorphous carbon can be used. In addition, as the anode, in addition to the above-mentioned carbon material, for example, a metal electrode formed of a metal such as nickel or Monel (trademark) can be used. In addition, as the cathode, for example, a metal electrode formed of metal such as iron, copper, nickel, Monel (trademark), etc. can be used.

The electrolyte contains hydrogen fluoride and metal fluoride. Although the type of the metal fluoride is not particularly limited, it is preferably a fluoride of at least one metal selected from potassium, cesium, rubidium, and lithium. When the electrolyte contains cesium or rubidium, the specific gravity of the electrolyte will increase, which can suppress the amount of mist generated during electrolysis.

As the electrolyte, for example, a mixed molten salt of hydrogen fluoride (HF) and potassium fluoride (KF) can be used. The molar ratio of hydrogen fluoride and potassium fluoride in the mixed molten salt of hydrogen fluoride and potassium fluoride can be, for example, hydrogen fluoride: potassium fluoride=1.5~2.5:1. Hydrogen fluoride: potassium fluoride = 2:1 when KF・2HF is a representative electrolyte. The melting point of this mixed molten salt is about 72°C. Since this electrolyte is corrosive, the contact parts of the electrolyte such as the inner surface of the electrolytic cell are preferably formed of iron, nickel, Monel (trademark) and other metals.

During the electrolysis of the electrolyte, a direct current is applied to the anode and the cathode, the fluorine-containing gas is generated at the anode, and the hydrogen-containing gas is generated at the cathode. In addition, the hydrogen fluoride in the electrolyte has vapor pressure, and hydrogen fluoride is mixed in the gas generated by the anode and cathode respectively. Furthermore, in the production of fluorine gas by the electrolysis of the electrolyte, the gas generated by the electrolysis contains the mist of the electrolyte. Therefore, the gas phase of the electrolytic cell is formed by the gas produced by electrolysis and the mist of hydrogen fluoride and electrolyte. Therefore, the output from the inside of the electrolytic cell to the outside is formed by the gas generated by the electrolysis and the mist of hydrogen fluoride and the electrolyte. In the present invention, this is referred to as "fluid".

However, as the hydrogen fluoride in the electrolyte is consumed through the progress of electrolysis, the piping for supplying hydrogen fluoride to the electrolytic cell continuously or intermittently may be connected to the electrolytic cell. The supply of hydrogen fluoride can be supplied to the cathode chamber side of the electrolytic cell, and can also be supplied to the anode chamber side. During the electrolysis of the electrolyte, the main reasons for the generation of mist are as follows. The temperature of the electrolyte during electrolysis is adjusted to, for example, 80-100°C. Because the melting point of KF・2HF is 71.7℃, when the temperature is adjusted to the above temperature, the electrolyte is in a liquid state. The gas bubbles generated by the two electrodes of the electrolytic cell rise in the electrolyte and break on the surface of the electrolyte. At this time, a part of the electrolyte is released into the gas phase.

Because the temperature of the gas phase is lower than the melting point of the electrolyte, the electrolyte released here changes into a very tiny powder state. The powder system should be KF·nHF, a mixture of potassium fluoride and hydrogen fluoride. This powder system takes the flow of other generated gases to become mist, forming the fluid produced by the electrolytic cell. Such fog system is difficult to effectively remove because of its adhesiveness, etc., only the usual countermeasures such as the installation of the filter.

In addition, although the amount of production is small, there may be cases where the fine powder of the organic compound is produced as a mist due to the reaction with the carbonaceous electrode of the anode and the fluorine gas generated by the electrolysis. In detail, the power supply part of the current to the carbon electrode often generates contact resistance, and through Joule heating, it may become a temperature higher than the temperature of the electrolyte. For this reason, the coal-like organic compound CFx may be generated as a mist through the reaction of carbon and fluorine gas, which forms the carbon electrode.

However, the electrolytic cell has a structure where the bubbles generated by the anode or cathode used in the electrolysis rise in the vertical direction in the electrolyte and reach the liquid surface of the electrolyte. When the bubbles are difficult to rise in the vertical direction in the electrolyte and have a structure that rises in an oblique direction with respect to the vertical direction, plural bubbles tend to gather into large bubbles. As a result, the large bubbles reach the liquid surface of the electrolyte and break up, and the amount of mist generated tends to increase. When the bubbles rise in the vertical direction in the electrolyte, they can reach the surface of the electrolyte. When small bubbles reach the surface of the electrolyte and break, the amount of mist is likely to be reduced.

[Average particle diameter measurement department] Although the fluorine gas production device of this embodiment may be equipped with an average particle diameter measuring unit that measures the average particle diameter of the mist contained in the fluid, this average particle diameter measuring unit is a light scattering detector that can measure the average particle diameter by the light scattering method To be constituted. The light scattering detector can measure the average particle diameter of the mist in the fluid flowing in the flow channel under the continuous operation of the fluorine gas production device, so it is better to be the average particle diameter measuring part.

An example of the light scattering detector will be described below with reference to FIG. 1. The light scattering detector of Fig. 1 is used in the fluorine gas production device of this embodiment (for example, the fluorine gas production device of Fig. 2 and Figs. 4 to 13 described later), and can be used as the light scattering part for measuring the average particle diameter. Chaos detector. That is, the electrolyte containing hydrogen fluoride and metal fluoride is electrolyzed inside the electrolytic cell of the fluorine gas production device to produce fluorine gas, and the average particle size of the mist contained in the fluid generated inside the electrolytic cell is measured. The trail of light scatters the detector. Connect the light scatter detector to the fluorine gas production device, and send the fluid from the inside of the electrolytic cell to the light scatter detector to measure the average particle diameter of the mist, or not connect the light scatter detector and the fluorine gas production device , Take out the fluid from the inside of the electrolytic cell and introduce it into the light scatter detector to measure the average particle diameter of the mist.

The light scatter detector in Fig. 1 is provided with a sample chamber 1 containing fluid F, a light source 2 for irradiating the fluid F in the sample chamber 1 with light L for light scatter measurement, and light L for detecting light scatter measurement The scattered light detector 3 for the scattered light S generated by the mist M in the fluid F being scattered, and the transparent window 4A, which is provided in the sample chamber 1 and is in contact with the fluid F and transmits the scattered light L for measuring light. The transparent window 4B is set in the sample chamber 1 in contact with the fluid F and transmits the scattered light S. The transparent windows 4A and 4B are selected from at least diamond, calcium fluoride (CaF ₂ ), potassium fluoride (KF), silver fluoride (AgF), barium fluoride (BaF ₂ ), and potassium bromide (KBr) 1 kind to be formed.

The scattered light measuring light L (such as laser light) emitted from the light source 2 enters the sample chamber 1 through the convergent lens 6 and the transparent window 4A of the sample chamber 1 and irradiates the fluid F contained in the sample chamber 1. At this time, when there is a substance that reflects light like mist M in the fluid F, the light L for light scattering measurement is reflected and scattered. A part of the scattered light S generated by the light L for light scattering measurement scattered through the mist M passes through the transparent window 4B of the sample chamber 1, and is taken out from the sample chamber 1 to the outside, and enters through the condenser lens 7 and the aperture 8. Scattered light detection section 3. At this time, based on the information obtained from the scattered light S, the average particle diameter of the mist M can be known. However, the average particle diameter obtained here is the average particle diameter of the number. As the scattered light detection unit 3, for example, an aerosol spectrometer welas (registered trademark) digital 2000 manufactured by PALAS Corporation can be used.

Although the transparent windows 4A and 4B are in contact with the fluid F, since the fluid F contains highly reactive fluorine gas, it is necessary to form the transparent windows 4A and 4B with a material that is difficult to be corroded by the fluorine gas. As the material for forming the transparent windows 4A, 4B, at least one selected from diamond, calcium fluoride, potassium fluoride, silver fluoride, barium fluoride, and potassium bromide can be cited. When the transparent windows 4A and 4B are formed of the above-mentioned material, deterioration caused by contact with the fluid F can be suppressed.

In addition, a film made of the above-mentioned materials can be coated on the surface of glass such as quartz and used as the transparent windows 4A, 4B. The part in contact with the fluid F is coated with a film made of the above-mentioned material, so that the deterioration caused by contact with the fluid F can be suppressed at a cost. The transparent windows 4A, 4B may be a laminated body in which the surface in contact with the fluid F is formed of the above-mentioned material, and the other parts are formed of ordinary glass such as quartz. The materials of the parts other than the transparent windows 4A and 4B in the light scattering detector are not particularly limited as long as they have corrosion resistance to fluorine gas. For example, copper-nickel alloy Monel (trademark) and HASTELLOY (trademark) are used. ), stainless steel and other metal materials are preferred.

[Average particle diameter of mist and water concentration in electrolyte] The inventors of the present invention measured the average particle diameter of the mist generated during the production of the fluorine gas generated by the electrolysis of the electrolyte using a light scattering detector. Explain an example of the result. Replace the anode of the fluorine gas production device with a new anode, fill the electrolytic cell with new electrolyte, open the tire, and measure the average particle diameter of the mist in the fluid generated by the anode until a certain period of time after the start of the electrolysis. As a result, the average particle diameter of the mist is 0.5 to 2.0 μm. After that, the electrolysis is continued. After a sufficient time, the electrolysis begins to stabilize. The average particle diameter of the mist in the fluid during the stable electrolysis is about 0.2μm. In this way, during the period from the start of electrolysis to the time of stable electrolysis, mist with a larger particle diameter is generated. When the fluid containing a large mist after the start of electrolysis flows into the piping or valve, the mist is adsorbed on the inner surface of the piping or valve, which is likely to cause blockage of the piping or valve.

In this regard, during stable electrolysis, the particle diameter of the mist produced is small. Since such a small mist system is difficult to settle or accumulate in the fluid, it can flow stably through piping or valves. For this reason, during stable electrolysis, the possibility of piping or valve clogging in the flow system of mist and gas generated at the electrode is low. However, the time from the start of electrolysis to the time of stable electrolysis is usually 25 hours or more and 200 hours or less. Also, from the start of electrolysis to the time of stable electrolysis, approximately 40kAh or more of electricity is required per 1000L of electrolyte.

In addition, the inventors discovered that there is a close relationship between the average particle diameter of the mist and the water concentration in the electrolyte. Generally, the water concentration in the electrolyte is large at the beginning of electrolysis, and shows a value larger than 1.0% by mass. The average particle diameter of the mist at this time is larger than 0.4μm. After that, as the electrolysis continues, the water concentration in the electrolyte decreases, and when it becomes 0.3% by mass or less, the average particle diameter of the mist becomes 0.4 μm or less.

In this way, the average particle diameter of the mist has a correlation with the water concentration in the electrolyte. It can be used to measure the water concentration in the electrolyte instead of the average particle diameter of the mist during electrolysis, and use the measurement result in the flow channel. Switch. That is, at a specific timing during electrolysis, when measuring the concentration of water in the electrolyte, corresponding to the measurement result, the flow path of the fluid generated by the flowing electrolysis is appropriately switched at the specific timing.

The deduction of the water concentration in the electrolyte is related to the size of the current value and the amount of energization (the product of the current value and the electrolysis time) and decreases. The higher the current value, the faster the reduction of the water concentration will be, which will produce a carbonaceous electrode with the anode effect that the voltage of the anode rises sharply. When used in the anode, the current density of the anode can be performed at a value smaller ^{than 0.1 A/cm 2} electrolysis. The water concentration can be decreased under a certain current density, or the water concentration can be decreased by slowly increasing the current density.

Based on such findings, the inventors invented the above-mentioned fluorine gas production method and fluorine gas production apparatus having a structure for switching the flow channel of the flowing fluid in accordance with the water concentration in the electrolyte during electrolysis. The fluorine gas production apparatus of the present embodiment has a first flow channel and a second flow channel, and a flow channel switching unit (for example, a switching valve) is used, and the flow channel used for conveying fluid may be selected from the two flow channels.

Or the fluorine gas production device of this embodiment has two flow channels, and a movement exchange mechanism for moving and exchanging the electrolytic cell. From the two flow channels, select the flow channel used for the fluid transportation, and the flow channel Nearby, it can be connected via a mobile electrolytic cell, and the flow channel can also be switched. As mentioned above, with the first flow channel and the second flow channel, while the one flow channel is cut off for cleaning, the other flow channel can be opened to continue the operation of the fluorine gas production device.

In the review conducted by the inventors, a mist with a relatively large average particle diameter was generated during the period from the start of electrolysis to the time of stable electrolysis. In this case, the second flow channel with the occlusion suppression mechanism may be used to transport fluid. When the time has elapsed, when the stable electrolysis is reached, a mist with a smaller average particle diameter is generated. At this time, the first flow channel with the mist removal part may be switched to the place where the fluid is transported.

Although the switching of the flow channel corresponds to the measured water concentration in the electrolyte, the switching of the flow channel can be performed according to a preset reference value. The appropriate reference value for the average particle diameter of the mist generated by the anode is different for each device, for example, it may be 0.1 μm or more and 1.0 μm or less, preferably 0.2 μm or more and 0.8 μm or less, and more preferably 0.4 μm. Therefore, from the perspective of the correlation between the average particle diameter of the mist and the water concentration in the electrolyte, the appropriate reference value for the water concentration in the electrolyte is 0.1% by mass or more and 0.8% by mass or less, preferably 0.2% by mass or more. 0.6% by mass or less, more preferably 0.3% by mass. When the water concentration in the electrolyte is greater than the reference value, the fluid can be transported in the second flow channel, and when it is below the reference value, the fluid can be transported in the first flow channel.

The water concentration in the electrolyte can be measured, for example, by the Karl Fischer method. Alternatively, the electrolyte can be heated to, for example, 250°C or more and 400°C or less, and the amount of moisture in the generated gas can be measured by, for example, infrared spectroscopy to obtain the moisture concentration in the electrolyte. In the detection solution used in the Karl Fischer method, the solid electrolyte is almost insoluble. Although other solvents for dissolving the solid electrolyte are needed, there are almost no solvents with high solubility for the solid electrolyte. Therefore, it is difficult to dissolve a large amount of solid electrolyte and perform Karl Fischer analysis. Therefore, the Karl Fischer method is suitable for the analysis of solid electrolytes with high water content. In contrast, the method of heating the solid electrolyte to measure the amount of moisture in the generated gas requires a longer analysis time than the Karl Fischer method, but it can analyze the moisture concentration in the electrolyte with better accuracy.

However, in the fluid produced by the cathode (the main component is hydrogen), for example, powder containing 20-50μg per unit volume (1 liter) (calculated assuming the specific gravity of the mist is 1.0 g/mL), the average particle size of this powder The diameter is about 0.1μm, with a distribution of ±0.05μm.

In the fluid produced by the cathode, there is no big difference in the particle size distribution of the powder produced through the concentration of water in the electrolyte. The mist contained in the fluid generated by the cathode has a smaller average particle diameter than the mist contained in the fluid generated by the anode. Therefore, compared with the mist contained in the fluid generated by the anode, it is difficult to cause piping or valve blockage. Therefore, the mist system contained in the fluid generated by the cathode can be removed from the fluid using an appropriate removal method.

An example of the fluorine gas production apparatus of this embodiment will be described in detail with reference to FIG. 2 below. Although the fluorine gas production device in Fig. 2 is an example with two electrolytic cells, the electrolytic cell may be one or more than three, for example, 10-15. The fluorine gas production device shown in FIG. 2 is equipped with electrolytic cells 11 and 11 that contain an electrolyte 10 inside and perform electrolysis, and an anode 13 that is immersed in the electrolytic solution 10, and an anode 13 that is arranged in the electrolytic cell 11 The inside is immersed in the electrolyte 10 and at the same time the cathode 15 is arranged facing the anode 13.

The inside of the electrolytic cell 11 extends vertically downward from the ceiling of the inside of the electrolytic cell 11, and is immersed in the partition wall 17 of the electrolytic solution 10 through the lower end, and is divided into an anode chamber 22 and a cathode chamber 24. Then, the anode 13 is arranged in the anode chamber 22 and the cathode 15 is arranged in the cathode chamber 24. However, the space on the liquid surface of the electrolyte 10 is separated into the space in the anode chamber 22 and the space in the cathode chamber 24 by the partition wall 17, and the part above the lower end of the partition wall 17 in the electrolyte 10 is separated by The partition wall 17 is separated, and the portion below the lower end of the partition wall 17 in the electrolyte 10 is continuous without being directly separated by the partition wall 17.

In addition, the fluorine gas production device shown in FIG. 2 is equipped with a moisture concentration measuring unit 36 that measures the moisture concentration in the electrolytic solution 10 in the electrolytic cell 11 during the electrolysis of the electrolytic solution 10, and the measurement during the electrolysis of the electrolytic solution 10 The first average particle diameter measuring section 31 containing the average particle diameter of the mist of the fluid generated in the inside of the electrolytic cell 11, the first mist removing section 32 which removes mist from the fluid, and the fluorine gas is extracted from the fluid. A fluorine gas extraction part (not shown), and a flow channel for conveying fluid from the inside of the electrolytic cell 11 to the fluorine gas extraction part.

Furthermore, this flow path has a first flow path that transports fluid from the inside of the electrolytic cell 11 to the fluorine gas extraction section through the first mist removal section 32, and does not go through the first mist removal section 32, and is removed from the electrolytic cell 11 The second flow channel for delivering fluid from the inside to the fluorine gas extraction part. In addition, this flow channel has a flow channel switching section that switches the flow channel of the flowing fluid to the first flow channel or the second flow channel in accordance with the moisture concentration in the electrolyte 10 measured by the moisture concentration measurement section 36. That is, in the middle of the flow passage extending from the electrolytic cell 11, a flow passage switching part is provided, and the flow passage of the flowing fluid can be changed via the flow passage switching part.

When the water concentration in the electrolytic solution 10 measured by the water concentration measuring unit 36 is less than the preset reference value, the flow channel switching section transports fluid from the inside of the electrolytic cell 11 to the first flow path, which is more preset When the reference value is large, the fluid is fed from the inside of the electrolytic cell 11 to the second flow channel. Then, the second flow path has an occlusion suppression mechanism that suppresses the occlusion caused by the mist of the second flow path.

That is, when the moisture concentration in the electrolyte 10 is below the reference value, connect the electrolytic cell 11 and the fluorine gas extraction part, and the first flow channel where the first mist removal part 32 is provided, transports the fluid and the moisture in the electrolyte 10 When the concentration is greater than the reference value, connect the electrolytic cell 11 and the fluorine gas extraction part, and the second flow path is provided with the blocking suppression mechanism to transport the fluid. As the moisture concentration measuring unit 36, for example, a Karl Fischer moisture measuring device can be used.

As the first mist removing section 32, for example, a mist removing device capable of removing mist having an average particle diameter of 0.4 μm or less from the fluid is used. The type of mist removal device, that is, the method of removing mist, although not particularly limited, the average particle diameter of the mist is small. For example, electric dust collectors, venturi cleaners, and filters can be used as mist removal Device to be used.

Among the above mist removing devices, the mist removing device shown in FIG. 3 is preferably used. The mist removal device shown in Figure 3 is a washer type mist removal device that uses liquid hydrogen fluoride as a circulating liquid. The mist removal device shown in Fig. 3 can efficiently remove mist with an average particle diameter of 0.4 μm or less from the fluid. In addition, although liquid hydrogen fluoride is used as the circulating fluid, it is better to cool the circulating fluid in order to reduce the concentration of hydrogen fluoride in the fluorine gas. The concentration of hydrogen fluoride in the fluorine gas can be adjusted by controlling the cooling temperature.

The fluorine gas production apparatus shown in Fig. 2 will be described in more detail. The fluid generated in the anode chamber 22 of the electrolytic cell 11 (hereinafter referred to as "anode gas") is sent to the outside first pipe 41, and then the electrolytic cell 11 and the fourth pipe 44 are connected, from the two electrolytic cells The anode gas sent from 11 and 11 is sent to the fourth pipe 44 via the first pipe 41 to be mixed. However, the main component of the anode gas is fluorine gas, and the secondary components are mist, hydrogen fluoride, carbon tetrafluoride, oxygen, and water.

The fourth pipe 44 is connected to the first mist removal section 32, and the anode gas is sent to the first mist removal section 32 through the fourth pipe 44. Therefore, the mist and hydrogen fluoride in the anode gas pass through the first mist removal section 32 to remove The anode gas is removed. The anode gas system for removing mist and hydrogen fluoride is sent from the first mist removing section 32 through the sixth pipe 46 connected to the first mist removing section 32 to a fluorine gas extraction section not shown. Then, the fluorine gas is extracted from the anode gas through the fluorine gas extraction unit and taken out.

However, the eighth pipe 48 is connected to the first mist removal part 32, and the liquid hydrogen fluoride of the circulating fluid is supplied to the first mist removal part 32 through the eighth pipe 48. Furthermore, a ninth pipe 49 is connected to the first mist removal part 32. The ninth pipe 49 is connected to the electrolytic cells 11 and 11 through the third pipe 43, and is used for removing mist in the first mist removing section 32. The circulating fluid (liquid hydrogen fluoride) containing mist is removed from the first mist The section 32 returns to the electrolytic cells 11,11.

The cathode chamber 24 of the electrolytic cell 11 is the same as the anode chamber 22. That is, if the fluid generated in the cathode chamber 24 of the electrolytic cell 11 (hereinafter referred to as "cathode gas") is sent to the second pipe 42 outside, the electrolytic cell 11 and the fifth pipe 45 are connected to each other. The cathode gas sent from the tanks 11 and 11 is sent to the fifth pipe 45 via the second pipe 42 to be mixed. However, the main component of the cathode gas is hydrogen, and the secondary components are mist, hydrogen fluoride, and water.

Because the cathode gas system contains fine mist and 5-10% by volume of hydrogen fluoride, it is not good to discharge it directly into the atmosphere. For this reason, the fifth pipe 45 is connected to the second mist removal part 33, the cathode gas is sent to the second mist removal part 33 through the fifth pipe 45, and the mist and hydrogen fluoride in the cathode gas are passed through the second mist removal part 33. , Remove the gas from the cathode. The cathode gas system for removing mist and hydrogen fluoride is discharged from the second mist removing section 33 to the atmosphere via the seventh pipe 47 connected to the second mist removing section 33. Although the type of the second mist removing section 33, that is, the method of removing mist is not particularly limited, a washer-type mist removing device using an aqueous alkali solution as a circulating liquid can be used.

Although the pipe diameters or installation directions of the first pipe 41, the second pipe 42, the fourth pipe 44, and the fifth pipe 45 (meaning the direction in which the pipe extends, such as the vertical direction and the horizontal direction) are not particularly limited, the first pipe 41 and The second piping 42 extends in the vertical direction from the electrolytic cell 11, and the flow velocity of the fluid flowing in the first piping 41 and the second piping 42 is 30 cm/sec or less in the standard state, and the pipe diameter is preferably set. In this way, when the mist contained in the fluid falls under its own weight, the mist settles in the electrolytic cell 11, and it is difficult to generate powder to block the inside of the first pipe 41 and the second pipe 42. In addition, the fourth pipe 44 and the fifth pipe 45 are extended in the horizontal direction, and the flow velocity of the fluid flowing in the fourth pipe 44 and the fifth pipe 45 is 1 to 10 times that of the first pipe 41 and the second pipe 42 It is better to set the pipe diameter quickly.

Furthermore, the second bypass pipe 52 for sending the anode gas to the outside of the electrolytic cell 11 is provided separately from the first pipe 41. That is, the second bypass piping 52 connects the electrolytic cell 11 and the first bypass piping 51, and the anode gas sent from the two electrolytic cells 11 and 11 is sent to the first bypass piping via the second bypass piping 52 51 to be mixed. Furthermore, through the first bypass pipe 51, the anode gas is sent to a fluorine gas extraction unit not shown. Then, the fluorine gas is extracted from the anode gas through the fluorine gas extraction unit and taken out. However, the fluorine gas extraction part connected to the first bypass pipe 51 and the fluorine gas extraction part connected to the sixth pipe 46 may be the same or different.

Although the pipe diameter or installation direction of the second bypass pipe 52 is not particularly limited, the second pipe 52 extends in the vertical direction from the electrolytic cell 11, and the flow velocity of the fluid flowing through the second bypass pipe 52 is 30 in the standard state. Below cm/sec, it is better to set the pipe diameter.

In addition, the first bypass pipe 51 is extended in the horizontal direction. Then, the first bypass pipe 51 is a pipe with a larger diameter than the fourth pipe 44, and the first bypass pipe 51 is so large that it is difficult to cause powder accumulation. Block 51. The first bypass pipe 51 is a pipe having a larger diameter than that of the fourth pipe 44, and constitutes a blocking suppression mechanism. The diameter of the first bypass pipe 51 is preferably greater than 1.0 times and less than 3.2 times of the fourth pipe 44, and more preferably 1.05 times or more and 1.5 times or less. That is, the cross-sectional area of the flow passage of the first bypass pipe 51 is preferably 10 times or less that of the fourth pipe 44.

As can be seen from the above description, the above-mentioned first flow passage is formed through the first pipe 41 and the fourth pipe 44, and the above-mentioned second flow passage is formed through the first bypass pipe 51 and the second bypass pipe 52. Then, a blocking suppression mechanism is provided in the first bypass pipe 51 constituting the second flow path.

Next, the flow channel switching unit will be described. The first piping 41 is provided with a first piping valve 61, respectively. Then, by switching the first piping valve 61 to the open state or the closed state, it is possible to control whether or not the anode gas is supplied from the electrolytic cell 11 to the first mist removal part 32. In addition, in the second bypass pipe 52, bypass valves 62 are respectively provided. Then, by switching the bypass valve 62 to the open state or the closed state, it is possible to control whether the anode gas is supplied from the electrolytic cell 11 to the first bypass pipe 51 or not.

Furthermore, the electrolytic cell 11 is provided with a moisture concentration measuring part 36, and the electrolytic solution 10 in the electrolytic cell 11 is introduced to the moisture concentration measuring part 36, and the moisture concentration in the electrolytic solution 10 can be measured during electrolysis. The electrolyte 10 for measuring the water concentration may be the electrolyte 10 on the anode chamber 22 side or the electrolyte 10 on the cathode chamber 24 side.

Furthermore, between the electrolytic cell 11 and the first mist removal part 32, in detail, in the middle part of the fourth pipe 44 and on the downstream side of the connecting part of the first pipe 41, a first average particle diameter measurement is provided部31. Then, the average particle diameter of the mist contained in the anode gas flowing through the fourth pipe 44 is measured via the first average particle diameter measuring unit 31. In addition, by analyzing the fluorine and nitrogen contained in the anode gas after measuring the average particle diameter of the mist, the current efficiency of the production of fluorine gas can be measured.

Then, in the middle part of the first bypass pipe 51, and on the downstream side of the connection part of the second bypass pipe 52, a second average particle diameter measuring unit 34 is also provided in the same way, via the second average particle diameter measuring unit 34, The average particle diameter of the mist contained in the anode gas flowing through the first bypass pipe 51 is measured. However, the fluorine gas production apparatus shown in FIG. 2 may not include the first average particle diameter measuring unit 31 and the second average particle diameter measuring unit 34.

The moisture concentration in the electrolytic solution 10 in the electrolytic cell 11 is measured through the moisture concentration measuring unit 36. When the measurement result is greater than the preset reference value, the bypass valve 62 is opened to remove the anode gas from the electrolytic cell. 11 is sent to the first bypass piping 51, and the first piping valve 61 is closed, so that the anode gas is not sent to the fourth piping 44 and the first mist removal part 32. That is, the anode gas is sent to the second flow channel.

On the other hand, when the measurement result is less than the preset reference value, the first piping valve 61 is opened, and the anode gas is sent to the fourth piping 44 and the first mist removal part 32, and the bypass valve 62 The closed state prevents anode gas from being sent from the electrolytic cell 11 to the first bypass pipe 51. That is, the anode gas is sent to the first flow channel. From the above description, it is understood that the above-mentioned flow path switching unit is constituted via the first piping valve 61 and the bypass valve 62.

As described above, corresponding to the water concentration in the electrolyte 10 during electrolysis, the fluorine gas production device is operated while switching the flow channel, and smoothly continuous operation is performed while suppressing the clogging of pipes or valves caused by mist. Therefore, according to the fluorine gas production apparatus shown in Fig. 2, fluorine gas can be produced economically.

For example, as a mist removal part, it is okay to prepare multiple piping with filters, switch the filters as appropriate, and perform electrolysis. Furthermore, the period during which the filter is frequently exchanged and the period during which the filter is not frequently exchanged can be judged based on the measurement of the water concentration in the electrolyte 10 during electrolysis. Then, based on the above judgment, when the switching frequency of the flowing fluid piping is appropriately adjusted, the operation of the fluorine gas production device can be efficiently continued.

Next, a modification example of the fluorine gas production apparatus shown in FIG. 2 will be described. [First Modification] The first modification will be described with reference to FIG. 4. Compared with the fluorine gas production device shown in FIG. 2, the second bypass pipe 52 connects the electrolytic cell 11 and the first bypass pipe 51. In the fluorine gas production device of the first modification shown in FIG. 4, the second bypass pipe The path piping 52 connects the first piping 41 and the first bypass piping 51. The configuration of the fluorine gas production apparatus of the first modification example is almost the same as that of the fluorine gas production apparatus of FIG. 2 except for the above-mentioned parts, and the description of the same parts is omitted.

[Second Modification] The second modification will be described with reference to FIG. 5. The fluorine gas production apparatus of the second modification shown in FIG. 5 is an example in which one electrolytic cell 11 is provided. The first average particle diameter measuring unit 31 is not the fourth pipe 44 but is provided in the first pipe 41 and is provided on the upstream side of the first pipe valve 61. In addition, the second bypass pipe 52 is not provided, and the first bypass pipe 51 is directly connected to the electrolytic cell 11 without the second bypass pipe 52.

Since the first bypass pipe 51 has a larger diameter than the fourth pipe 44, it functions as a blocking suppression mechanism. Furthermore, for example, through the downstream end of the first bypass pipe 51, a space for mist storage is provided to further increase the effect of suppressing the occlusion. As the space for storing the mist, for example, a pipe diameter formed in the downstream end portion of the first bypass pipe 51 to be larger than the central portion in the installation direction (for example, 4 times or more pipe diameter of the central portion in the installation direction) The space formed or the downstream end portion of the first bypass pipe 51 is formed into a container-shaped space, and the clogging of the first bypass pipe 51 can be suppressed through the space for mist storage. This is for the effect of preventing occlusion caused by the large cross-sectional area of the flow path, and the effect of preventing the occlusion of the mist caused by the gravity drop caused by the decrease of the linear velocity of the gas flow. Furthermore, the bypass valve 62 is provided in the third bypass pipe 53 connecting the first bypass pipe 51 and the fluorine gas extraction part not shown. The configuration of the fluorine gas production apparatus of the second modification example is almost the same as that of the fluorine gas production apparatus of FIG. 2 except for the above-mentioned parts, and the description of the same parts is omitted.

[3rd Modification] The third modification will be described with reference to FIG. 6. In the fluorine gas production device of the third modification, the first average particle diameter measuring part 31 is provided in the electrolytic cell 11, and the anode gas inside the electrolytic cell 11 is directly introduced into the first average particle diameter measuring part 31 to perform the average particle diameter of the mist. Determination of diameter. The fluorine gas production apparatus of the third modification does not have the second average particle diameter measuring unit 34. The configuration of the fluorine gas production apparatus of the third modification example is almost the same as that of the fluorine gas production apparatus of the second modification example except for the above-mentioned parts, and the description of the same parts is omitted.

[4th Modification] The fourth modification will be described with reference to FIG. 7. The fluorine gas production apparatus of the fourth modification is a different example from the second modification shown in FIG. 5 in which the occlusion suppression mechanism is different. In the fluorine gas production device of the second modification example, the first bypass pipe 51 is extended in the horizontal direction, but in the fluorine gas production device of the fourth modification example, the first bypass pipe 51 is inclined with respect to the horizontal direction. , And extend toward the descending direction from the upstream side to the downstream side. By this inclination, it is possible to prevent the powder from accumulating inside the first bypass pipe 51. The greater the tilt, the greater the effect of inhibiting the accumulation of powder.

The inclination angle of the first bypass pipe 51 is a range where the depression angle from the horizontal plane is smaller than 90 degrees, preferably 30 degrees or more, and more preferably 40 degrees or more and 60 degrees or less. If the first bypass piping 51 is about to be blocked, and the inclined first bypass piping 51 is hammered, the deposits inside the first bypass piping 51 will become easy to move, and the blocking can be avoided. The configuration of the fluorine gas production apparatus of the fourth modification example is almost the same as that of the fluorine gas production apparatus of the second modification example except for the above-mentioned parts, and the description of the same parts is omitted.

[Fifth Modification] The fifth modification will be described with reference to FIG. 8. The fluorine gas production apparatus of the fifth modification is a different example from the third modification shown in FIG. 6 in which the occlusion suppression mechanism is different. In the fluorine gas production device of the third modification, the first bypass pipe 51 is extended in the horizontal direction, but in the fluorine gas production device of the fifth modification, the first bypass pipe 51 is inclined with respect to the horizontal direction. , And extend toward the descending direction from the upstream side to the downstream side. By this inclination, it is possible to prevent the powder from accumulating inside the first bypass pipe 51. The preferable inclination angle of the first bypass pipe 51 is the same as that of the fourth modification described above. The configuration of the fluorine gas production apparatus of the fifth modification example is almost the same as that of the fluorine gas production apparatus of the third modification example except for the above-mentioned parts, and the description of the same parts is omitted.

[6th Modification] The sixth modification will be described with reference to FIG. 9. The fluorine gas production apparatus of the sixth modification is a different example from the second modification shown in FIG. 5 in that the structure of the electrolytic cell 11 is different. The electrolytic cell 11 has one anode 13 and two cathodes 15 and 15, and is divided into one anode chamber 22 and one cathode chamber 24 via a cylindrical partition wall 17 surrounding one anode 13. The anode chamber 22 is formed by extending above the upper surface of the electrolytic cell 11, and the first bypass pipe 51 is connected to the upper end portion of the anode chamber 22 of the electrolytic cell 11. The configuration of the fluorine gas production apparatus of the sixth modification example is almost the same as that of the fluorine gas production apparatus of the second modification example except for the above-mentioned parts, and the description of the same parts is omitted.

[7th Modification] The seventh modification will be described with reference to FIG. 10. The fluorine gas production apparatus of the seventh modification is a different example from the sixth modification shown in FIG. 9 in that the structure of the first bypass pipe 51 is different. That is, in the fluorine gas production device of the seventh modification, the first bypass pipe 51 is the same as the fourth and fifth modifications. direction. The preferable inclination angle of the first bypass pipe 51 is the same as that of the fourth modification described above. The configuration of the fluorine gas production apparatus of the seventh modification example is almost the same as that of the fluorine gas production apparatus of the sixth modification example except for the above-mentioned parts, and the description of the same parts is omitted.

[Eighth Modification] The eighth modification will be described with reference to FIG. 11. The fluorine gas production apparatus of the eighth modification is a different example from the second modification shown in FIG. 5 in that the occlusion suppression mechanism is different. In the fluorine gas production apparatus of the eighth modification, the rotating screw 71 constituting the occlusion suppression mechanism is installed inside the first bypass pipe 51. The rotating screw 71 is provided with the rotating shaft parallel to the longitudinal direction of the first bypass pipe 51. Then, the rotating screw 71 is rotated by the motor 72, and the mist accumulated in the first bypass pipe 51 is sent to the upstream side or the downstream side. This can prevent the powder from accumulating in the first bypass pipe 51. The configuration of the fluorine gas production apparatus of the eighth modification example is almost the same as that of the fluorine gas production apparatus of the second modification example except for the above-mentioned parts, and the description of the same parts is omitted.

[Ninth Modification] The ninth modification will be described with reference to FIG. 12. The fluorine gas production apparatus of the ninth modification is a different example from the second modification shown in FIG. 5 in that the occlusion suppression mechanism is different. In the fluorine gas production apparatus of the ninth modification example, the air flow generating device 73 constituting the blockage suppression mechanism is installed inside the first bypass pipe 51. The air flow generator 73 sends an air flow (for example, a nitrogen gas flow) from the upstream side to the downstream side of the first bypass pipe 51 and flows upward at the flow velocity of the anode gas in the first bypass pipe 51. This can prevent the powder from accumulating in the first bypass pipe 51.

The preferred flow velocity of the anode gas flowing in the first bypass pipe 51 at this time is 1 m/sec or more and 10 m/sec or less. Although the flow velocity can be greater than 10 m/sec, the pressure loss caused by the resistance of the piping in the first bypass piping 51 will increase, and the pressure in the anode chamber 22 of the electrolytic cell 11 will increase. It is better if the pressure in the anode chamber 22 and the pressure in the cathode chamber 24 are almost the same. When the pressure in the anode chamber 22 and the pressure in the cathode chamber 24 are too large, the anode gas flows across the partition wall 17 into the cathode. In the chamber 24, the fluorine gas reacts with the hydrogen gas, which hinders the generation of the fluorine gas. The configuration of the fluorine gas production apparatus of the ninth modification example is almost the same as that of the fluorine gas production apparatus of the second modification example except for the above-mentioned parts, and the description of the same parts is omitted.

[Tenth Modification] The tenth modification will be described with reference to FIG. 13. In the fluorine gas production apparatus of the tenth modification, the first average particle diameter measuring unit 31 is provided in the electrolytic cell 11, and the anode gas inside the electrolytic cell 11 is directly introduced into the first average particle diameter measuring unit 31 to perform the average particle diameter measurement of the mist. Determination of diameter. The fluorine gas production apparatus of the tenth modification does not have the second average particle diameter measuring unit 34. The configuration of the fluorine gas production apparatus of the tenth modification example is almost the same as that of the fluorine gas production apparatus of the ninth modification example shown in FIG. 12 except for the above-mentioned parts, and the description of the same parts is omitted. [Example]

Hereinafter, examples and comparative examples are shown to explain the present invention in more detail. [Reference Example 1] Electrolyte electrolyte to produce fluorine gas. As the electrolyte, a mixed molten salt (560L) of 434kg of hydrogen fluoride and 630kg of potassium fluoride was used. As the anode, an amorphous carbon electrode (30 cm wide, 45 cm long, 7 cm thick) manufactured by SGLBabon was used, and 16 anodes were set in the electrolytic cell. In addition, a perforated plate of Monel (trademark) is used as the cathode, and an electrolytic cell is installed. For one anode and two cathodes, the total area of one anode facing the cathode is 1736cm ² .

The electrolysis temperature is controlled at 85~95℃. First, set the temperature of the electrolyte to 85°C, apply a direct current of 1000 ^{A at a current density of 0.036 A/cm 2, and start electrolysis.} At this time, the water concentration in the electrolyte is 1.0% by mass. However, the water concentration can be determined by Karl Fischer analysis. The electrolysis was started under the above conditions. During 10 hours after the start of electrolysis, a small cracking sound was observed near the anode in the anode chamber. This cracking sound should be produced by the reaction of the generated fluorine gas with the moisture in the electrolyte.

In this state, the fluid generated by the anode is sent from the anode chamber of the electrolytic cell to the outside and collected, and the mist contained in the fluid is analyzed. As a result, the fluid produced by the anode contains 5.0 to 9.0 mg of powder per 1 L (calculated assuming that the specific gravity of the mist is 1.0 g/mL. The same applies to the following.) The average particle diameter of this powder is 1.0 to 2.0 μm. As a result of observing the powder with an optical microscope, it is mainly observed that the powder has a shape passing through the inside of the ball. In addition, the current efficiency of fluorine gas generation at this time is 0-15%.

What's more, when the energizing power continues to electrolyze to 30kAh, the frequency of cracking sound inside the anode chamber is reduced. At this time, the water concentration in the electrolyte is 0.7% by mass. Also, in this state, the fluid generated by the anode is sent from the anode chamber of the electrolytic cell to the outside and collected, and the mist contained in the fluid is analyzed. As a result, the fluid generated by the anode contains 0.4~1.0mg of mist per 1L, and the average particle diameter of this mist is 0.5~0.7μm. Moreover, the current efficiency of fluorine gas generation at this time is 15~55%. Let the electrolysis stage from the beginning of the electrolysis to this point be "stage (1)".

Furthermore, following stage (1), the electrolysis of the electrolyte is continued. As a result, the hydrogen fluoride is consumed, and the water level of the electrolyte drops, so hydrogen fluoride is appropriately supplied from the hydrogen fluoride tank to the electrolytic tank. The water concentration in the supplied hydrogen fluoride is below 500 mass ppm. Furthermore, when the electrolysis is continued and the current flow reaches 60 kAh, the average particle diameter of the mist contained in the fluid generated by the anode becomes 0.36 μm (that is, 0.4 μm or less). At this time, there is no cracking sound inside the anode chamber. In addition, the water concentration in the electrolyte at this time is 0.2% by mass (that is, 0.3% by mass or less). Moreover, the current efficiency of fluorine gas generation at this time is 65%. Let the electrolysis stage from the termination point of stage (1) to this point be "stage (2)".

Furthermore, the current is increased to 3500A, the current density is increased to 0.126 A/cm ² , and stage (2) is continued, and the electrolysis of the electrolyte is continued. In this state, the fluid generated by the anode is sent from the anode chamber of the electrolytic cell to the outside and collected, and the mist contained in the fluid is analyzed. As a result, the fluid produced by the anode contains 0.03~0.06mg of powder per 1L. The average particle diameter of this powder is about 0.2μm (0.15~0.25μm), and the particle diameter has a distribution of about 0.1~0.5μm. . Figure 14 shows the measurement result of the particle size distribution of this powder. Moreover, the current efficiency of fluorine gas generation at this time is 94%. At this time, the water concentration in the electrolyte is less than 0.2% by mass. Let the electrolysis phase from the termination point of phase (2) to this point be the "stable phase".

The content of the electrolysis of Reference Example 1 performed as described above is shown in Table 1 in its entirety. In Table 1, with current, electrolysis elapsed time, energization amount, water concentration in the electrolyte, the fluid produced by the anode (referred to as "anode gas" in Table 1), the mass of the mist contained in 1L, and the average particle size of the mist The diameter and current efficiency also show the amount of fluid (containing fluorine, oxygen, and mist) produced by the anode, the amount of mist produced by the anode, the intensity of the cracking sound, and the concentration of water in the fluid produced by the cathode (table Recorded as "water concentration in cathode gas" in 1).

In addition, a graph showing the relationship between the average particle diameter of the mist and the amount of mist generated by the anode is shown in FIG. 15. From the graph in Figure 15, it can be seen that there is a correlation between the average particle diameter of the mist and the amount of mist generated by the anode. The more the amount of mist is generated, the occlusion of pipes or valves is likely to occur. When a mist larger than the average particle diameter of 0.4μm is generated, the amount of mist generated will increase, and the amount of mist will be precipitated by the action of gravity. The graph in Figure 15 The relationship shown can be said to indicate the correlation between the average particle diameter of the mist and the degree of occlusion of the pipe or valve. Furthermore, a graph showing the relationship between the average particle diameter of the mist and the moisture concentration in the electrolyte is shown in FIG. 16. The larger the average particle diameter of the mist, the more likely it is to cause piping or valve clogging. The relationship shown in the graph in Figure 16 can be said to indicate the relationship between the concentration of water in the electrolyte and the degree of occlusion of the piping or valve. sex.

[Example 1] The same electrolysis as in Reference Example 1 was performed using the fluorine gas production apparatus shown in FIG. 2. In the electrolysis of stage (1), the fluid generated by the anode is circulated through the second bypass pipe, the bypass valve, and the first bypass pipe. After the electrolysis of stage (1) is terminated, the electrolysis is temporarily stopped, and the internal inspection of the fluorine gas production device is carried out. As a result, although mist accumulated in the first bypass piping, the piping was not blocked due to the large diameter of the piping.

As the average particle diameter of the mist is 0.4μm or less (the water concentration in the electrolyte is 0.2% by mass of 0.3% by mass or less of the reference value), the fluid generated by the anode is passed through the first step (2) of electrolysis. The piping, the first piping valve, the fourth piping, and the first mist removal part circulate. No accumulation or obstruction of mist occurs in the first piping, the first piping valve, and the fourth piping, and the flow system generated by the anode is supplied to the first mist removal part, and the mist is removed in the first mist removal part. The first mist removal part is a washer-type removal part that sprays liquid hydrogen fluoride and removes particles such as mist. The mist removal rate is 98% or more.

[Comparative example 1] In the electrolysis of stage (1), except that the fluid generated by the anode is circulated through the first pipe, the first pipe valve, the fourth pipe, and the first mist removal part, it is the same as that of Example 1. Perform the same electrolysis. In the electrolysis of stage (1), the measured value of the pressure gauge on the anode side of the pressure gauges installed on the anode and cathode sides of the electrolytic cell gradually becomes higher, and the difference between the pressure on the cathode side and the pressure on the cathode side becomes 90 mmH ₂ O Therefore, stop electrolysis. The reason for the suspension is as follows. The part of the electrolyte immersed in the partition wall in the electrolytic cell has a vertical length (immersion length) of 5 cm. When the pressure on the anode side is about 100 mmH ₂ O higher than the pressure on the cathode side, the electrolyte on the anode side The liquid level is lower than the lower end of the partition wall. As a result, the fluorine gas crosses the partition wall and mixes with the hydrogen gas on the cathode side, causing a violent reaction between the fluorine gas and the hydrogen gas, which is very dangerous.

After exhausting nitrogen gas in the system, check the inside of the first piping, the first piping valve, and the fourth piping. As a result, the first piping is a pipe extending in the vertical direction and is not blocked. A small amount of powder is attached to the first piping valve, and the downstream side of the first piping valve, that is, the inlet of the fourth piping, is blocked by the powder. The fourth pipe also has powder accumulation, but it is not enough to block the pipe.

1: sample room 2: light source 3: Scattered light detection section 4A, 4B: transparent window 10: Electrolyte 11: Electrolyzer 13: anode 15: Cathode 22: anode chamber 24: Cathode chamber 31: The first average particle diameter measuring section 32: The first mist removal part 33: The second mist removal part 34: The second average particle diameter measuring part 36: Water concentration measurement department 41: The first piping 42: 2nd piping 43: 3rd piping 44: 4th piping 45: 5th piping 46: 6th piping 47: No. 7 piping 48: 8th piping 49: 9th piping 51: 1st bypass piping 52: 2nd bypass piping 61: The first piping valve 62: Bypass valve F: fluid L: Light used for light scattering measurement M: mist S: Scattered light

[Fig. 1] A schematic diagram illustrating an example of a light scattering detector used as an average particle diameter measuring unit in a fluorine gas production apparatus according to an embodiment of the present invention. [Fig. 2] A schematic diagram illustrating an example of a fluorine gas production apparatus related to an embodiment of the present invention. [Fig. 3] In the fluorine gas production device of Fig. 2, a schematic diagram illustrating an example of a mist removal device used as a mist removal unit. [Fig. 4] A schematic diagram illustrating a first modification of the fluorine gas production apparatus of Fig. 2. [Fig. [Fig. 5] A schematic diagram illustrating a second modification of the fluorine gas production apparatus of Fig. 2. [Fig. [Fig. 6] A schematic diagram illustrating a third modification of the fluorine gas production apparatus of Fig. 2. [Fig. [Fig. 7] A schematic diagram illustrating a fourth modification of the fluorine gas production apparatus of Fig. 2. [Fig. [Fig. 8] A schematic diagram illustrating a fifth modification of the fluorine gas production apparatus of Fig. 2. [Fig. [Fig. 9] A schematic diagram illustrating a sixth modification of the fluorine gas production apparatus of Fig. 2. [Fig. [Fig. 10] A schematic diagram illustrating a seventh modification of the fluorine gas production apparatus of Fig. 2. [Fig. [Fig. 11] A schematic diagram illustrating an eighth modification of the fluorine gas production apparatus of Fig. 2. [Fig. [Fig. 12] A schematic diagram illustrating a ninth modification of the fluorine gas production apparatus of Fig. 2. [Fig. [Fig. 13] A schematic diagram illustrating a tenth modification of the fluorine gas production apparatus of Fig. 2. [Fig. [Figure 14] In Reference Example 1, a graph showing the particle diameter distribution of the mist contained in the fluid generated by the anode. [Figure 15] In Reference Example 1, a graph showing the correlation between the average particle diameter of the mist and the amount of mist generated by the anode. [Figure 16] In Reference Example 1, a graph showing the relationship between the average particle diameter of the mist and the moisture concentration in the electrolyte.

10: Electrolyte

11: Electrolyzer

13: anode

15: Cathode

17: next wall

22: anode chamber

24: Cathode chamber

31: The first average particle diameter measuring section

32: The first mist removal part

33: The second mist removal part

34: The second average particle diameter measuring part

36: Water concentration measurement department

41: The first piping

42: 2nd piping

43: 3rd piping

44: 4th piping

45: 5th piping

46: 6th piping

47: No. 7 piping

48: 8th piping

49: 9th piping

51: 1st bypass piping

52: 2nd bypass piping

61: The first piping valve

62: Bypass valve

Claims (5)

A method for producing fluorine gas, electrolyzing an electrolyte containing hydrogen fluoride and metal fluoride, and producing fluorine gas. Its characteristics are Possess: In the electrolytic cell, carry out the electrolysis process of the aforementioned electrolysis, And during the aforementioned electrolysis, the water concentration measurement process to measure the water concentration in the aforementioned electrolyte, And during the electrolysis of the aforementioned electrolyte, the fluid generated inside the aforementioned electrolytic cell is transported from the inside of the aforementioned electrolytic cell to the outside flow channel through the gas supply process; In the aforementioned gas supply project, corresponding to the water concentration in the electrolyte measured by the aforementioned water concentration measurement project, the flow channel through which the fluid flows is switched, and the water concentration in the aforementioned electrolyte measured by the aforementioned water concentration measurement project is a preset reference When the value is less than or equal to the value below, in the first flow path that transports the fluid from the inside of the electrolytic cell to the first outside, and when the fluid is transported, the fluid is transported from the inside of the electrolytic cell to the first 2 The second flow channel for externally transporting the aforementioned fluid, transporting the aforementioned fluid, The aforementioned preset reference value is a value within the range of 0.1% by mass to 0.8% by mass. The method for producing fluorine gas according to claim 1, wherein the metal fluoride is a fluoride of at least one metal selected from potassium, cesium, rubidium, and lithium. The method for producing fluorine gas according to claim 1 or 2, wherein the anode used in the aforementioned electrolysis is formed of at least one carbon material selected from diamond, diamond-like carbon, amorphous carbon, graphite, and glassy carbon The carbon electrode. The method for producing fluorine gas according to any one of claims 1 to 3, wherein the electrolytic cell has air bubbles generated by the anode or cathode used in the electrolysis, which rise in the vertical direction in the electrolytic solution, The structure that can reach the liquid level of the aforementioned electrolyte. A fluorine gas production device that electrolyzes an electrolyte containing hydrogen fluoride and metal fluoride to produce fluorine gas. Its characteristics are Equipped with: an electrolytic cell for accommodating the aforementioned electrolyte and performing the aforementioned electrolysis, And during the aforementioned electrolysis, the water concentration measuring part that measures the water concentration in the electrolyte in the aforementioned electrolytic cell, And during the electrolysis of the aforementioned electrolyte, the fluid produced in the aforementioned electrolytic tank is transported from the inside of the aforementioned electrolytic tank to the outside; The flow channel has a first flow channel that transports the fluid from the inside of the electrolytic cell to the first outside, and a second flow channel that transports the fluid from the inside of the electrolytic cell to the second outside, and has a corresponding The water concentration in the electrolyte measured by the water concentration measuring part switches the flow path through which the fluid flows to the flow path switching part of the first flow path or the second flow path, The flow path switching unit transports the fluid from the inside of the electrolytic cell to the first flow path when the water concentration in the electrolyte measured by the water concentration measurement unit is below a preset reference value. When the predetermined reference value is large, the fluid is fed from the inside of the electrolytic cell to the second flow path, The aforementioned preset reference value is a value within the range of 0.1% by mass to 0.8% by mass.

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