TW202138622A - Method for producing fluorine gas and device for producing fluorine gas - Google Patents

Abstract

Provided is a method for producing fluorine gas, the method making it possible to suppress blockage of piping or valves caused by mist. According to the present invention, fluorine gas is produced through a method comprising: an electrolysis step for electrolyzing a liquid electrolyte inside an electrolysis tank; an electricity conduction measurement step for measuring an integral electricity conduction amount after the liquid electrolyte has been charged into the electorlysis tank and the electrolysis has been started; and an air supply step for supplying, from inside the electrolysis tank to an external section via a flow path, a fluid generated inside the electrolysis tank during electrolysis of the liquid electrolyte. In the air supply step, the flow path through which the fluid is channeled is switched in accordance with the electricity conduction amount measured in the electricity conduction measurement step. The air supply step is configured so that: when the electricity conduction amount measured in the electricity conduction measurement step is equal to or greater than a preset reference value, the fluid is supplied to a first flow path for supplying the fluid from inside the electrolysis tank to a first external section; when said electricity conduction amount is less than the preset reference value, the fluid is supplied to a second flow path for supplying the fluid from inside the electrolysis tank to a second external section. The preset reference value is equal to or greater than 40 kAh per 1000 L of the liquid electrolyte.

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.

Fluorine gas can be synthesized by electrolyzing an electrolyte containing hydrogen fluoride and metal fluoride (electrolytic synthesis). Since the electrolysis of the electrolyte causes mist droplets (for example, mist droplets of the electrolyte solution) to be generated together with the fluorine gas, the mist droplets are accompanied by the fluorine gas sent from the electrolytic cell. The mist accompanying the fluorine gas is powder, and there is a risk of clogging the pipes and valves used for the fluorine gas supply. For this reason, sometimes the operation of producing fluorine gas has to be interrupted or stopped, which becomes an obstacle to continuous operation in the production of fluorine gas by the electrolysis method. In order to suppress clogging of piping and valves caused by mist droplets, Patent Document 1 discloses a technique of heating the fluorine gas accompanying mist droplets or the piping through which the gas passes above the melting point of the electrolyte. In addition, Patent Document 2 discloses a gas generating device having a gas diffusion part as a space for rough processing of mist droplets, and a filling material accommodating part accommodating a filling material for adsorbing mist droplets. [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, technology that can more effectively suppress clogging of pipes and valves caused by mist is expected. The subject of the present invention is to provide a fluorine gas production method and a fluorine gas production device that can suppress clogging of pipes and valves caused by mist droplets. [Technical 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] A method of producing fluorine gas by electrolyzing an electrolyte solution containing hydrogen fluoride and metal fluoride to produce fluorine gas, It has: Perform the electrolysis procedure of the aforementioned electrolysis in an electrolytic cell, The energization amount measurement program for measuring the accumulated energization amount since the electrolytic solution is filled into the electrolytic cell and the electrolysis is started, and A gas supply process in which the fluid generated inside the electrolytic cell during the electrolysis of the electrolytic solution is transported from the inside of the electrolytic cell to the outside via a flow channel, Wherein, in the air supply program, the flow path through which the fluid circulates is switched according to the energization amount measured in the energization amount measurement program, and the energization amount measured in the energization amount measurement program is a preset reference If the value is greater than the value, the fluid is fed to the first flow path that feeds the fluid from the inside of the electrolytic cell to the first outside. If the fluid is smaller than the preset reference value, 2 The second flow channel for externally transporting the aforementioned fluid transports the aforementioned fluid, The aforementioned predetermined reference value is a value within the range of 40 kAh or more per 1000 L of the aforementioned electrolyte.

[2] The method for producing fluorine gas according to [1], wherein the metal fluoride is at least one metal fluoride selected from potassium, cesium, rubidium, and lithium. [3] The method for producing fluorine gas according to [1] or [2], wherein the anode used in the aforementioned electrolysis is a carbon made of at least one selected from diamond, diamond-like carbon, amorphous carbon, graphite, and glassy carbon The carbon electrode formed by the material. [4] The method for producing fluorine gas according to any one of [1] to [3], wherein the electrolytic cell has air bubbles generated at the anode or cathode used in the electrolysis and rises in the vertical direction in the electrolytic solution. A structure that can reach the liquid surface of the aforementioned electrolyte.

[5] A fluorine gas production device that produces fluorine gas by electrolyzing an electrolyte solution containing hydrogen fluoride and metal fluoride, It has: An electrolytic cell that contains the foregoing electrolyte and performs the foregoing electrolysis, A energization amount measuring unit that measures the accumulated energization amount since the electrolytic solution is filled in the electrolytic cell and the electrolysis is started, and A flow channel that transports the fluid generated inside the electrolytic cell during the electrolysis of the electrolytic solution from the inside of the electrolytic cell to the outside, Among them, 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 also has a energization dependent on the above. The energization amount measured by the quantity measuring section switches the flow path through which the fluid flows to the flow path switching section for the first flow path or the second flow path, In the case where the energization amount measured by the energization amount measuring unit is equal to or greater than a preset reference value, the flow path switching unit transports the fluid from the inside of the electrolytic cell to the first flow path, which is higher than the preset value. When the reference value of is small, transport the fluid from the inside of the electrolytic cell to the second flow path, The aforementioned predetermined reference value is a value within the range of 40 kAh or more per 1000 L of the aforementioned electrolyte. [Compared with the effect of the previous technology]

According to the present invention, it is possible to suppress clogging of pipes and valves caused by mist droplets when electrolyzing an electrolyte solution containing hydrogen fluoride and metal fluoride to produce fluorine gas.

An embodiment of the present invention will be described below. In addition, this embodiment is an example of this invention, and this invention is not limited to this embodiment. In addition, various changes or improvements can be added to this embodiment, and an aspect in which such changes or improvements are added may also be included in the present invention.

The present inventors intensively conducted a review on the droplets that cause clogging of piping and valves in the electrolytic synthesis of fluorine gas. The "mist" in the present invention refers to liquid particles and solid particles that are generated together with fluorine gas in the electrolytic cell due to the electrolysis of the electrolyte. Specifically, it refers to the particles of the electrolyte, the solid particles in which the particles of the electrolyte are phase-changeable, and the components that constitute the electrolytic cell (the metal that forms the electrolytic cell, the gasket for the electrolytic cell, the carbon electrode, etc.) and the fluorine gas generation Solid particles produced by the reaction.

The inventors of the present invention measured the average particle size of the mist droplets included in the fluid generated inside the electrolytic cell during the electrolysis of the electrolytic solution, and confirmed that the average particle size of the mist droplets changed with time. In addition, as a result of intensive review, it was found that there is a correlation between the average particle size of the mist droplets and the accumulated energization amount during electrolysis, and the average particle size of the mist droplets and the susceptibility to clogging of the piping and valves of the conveying fluid There is a correlation between. In addition, it has been discovered that the accumulated energization amount during electrolysis can be used to transport the fluid generated in the inside of the electrolytic cell, thereby suppressing clogging of piping and valves, and reducing the interruption and stoppage of the operation of producing fluorine gas. Frequency, thus completing the present invention. One embodiment of the present invention will be described below.

The method for producing fluorine gas in this embodiment is a method for producing fluorine gas, which is a method for producing fluorine gas by electrolyzing an electrolyte containing hydrogen fluoride and metal fluoride, and is equipped with an electrolysis procedure and measurement for electrolysis in an electrolytic cell. The energization measurement program of the accumulated energization amount calculated from the time when the electrolyte is filled in the electrolytic cell and the electrolysis is started, and the fluid generated inside the electrolytic cell during the electrolysis of the electrolyte is passed from the inside of the electrolytic cell to the outside through the flow channel And the gas supply program of the transportation.

In the air supply program, the flow channel through which the fluid flows is switched according to the energization amount measured in the energization amount measurement program. That is, when the energization amount measured by the energization amount measurement program is more than the preset reference value, the fluid is sent to the first flow channel that transports the fluid from the inside of the electrolytic cell to the first outside, which is higher than the preset reference value. When the reference value is small, the fluid is sent to the second flow path that sends the fluid from the inside of the electrolytic cell to the second outside. In addition, regarding the preset reference value, the electrolytic solution is set to a value within the range of 40 kAh or more per 1000 L.

In addition, the fluorine gas production device of this embodiment is a fluorine gas production device that produces fluorine gas by electrolyzing an electrolyte solution containing hydrogen fluoride and metal fluoride. The energization amount measuring unit for the accumulated energization amount from the start of electrolysis is loaded in the electrolytic cell, and a flow channel that conveys the fluid generated inside the electrolytic cell during the electrolysis of the electrolytic solution from the inside of the electrolytic cell to the outside.

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 through which the fluid flows in accordance with the energization amount measured by the energization amount measurement section to the first flow channel or the second flow channel. When the energization amount measured by the energization amount measuring unit is greater than or equal to the preset reference value, the flow channel switching unit sends the fluid from the inside of the electrolytic cell to the first flow path, which is smaller than the preset reference value Next, the fluid is sent from the inside of the electrolytic cell to the second flow channel. In addition, regarding the preset reference value, the electrolytic solution is set to a value within the range of 40 kAh or more per 1000 L.

In the fluorine gas production method and the fluorine gas production apparatus of this embodiment, the energization amount calculated from the time when the electrolyte is filled in the electrolytic cell and electrolysis is started (hereinafter, sometimes simply referred to as "energization amount" or "accumulated amount" Electricity"), the flow channel through which the fluid flows is switched to the first flow channel or the second flow channel, so the result is that the flow channel is switched to the first flow channel or the second flow channel according to the average particle size of the droplets , It is not prone to blockage of the flow channel caused by mist droplets. For this reason, the fluorine gas production method and fluorine gas production apparatus of the present embodiment can suppress clogging of pipes and valves caused by mist droplets when electrolyzing an electrolyte containing hydrogen fluoride and metal fluoride to produce fluorine gas. Therefore, the frequency of interruption and stoppage of the operation of producing fluorine gas can be reduced, and continuous operation can be easily performed. For this reason, fluorine gas can be produced economically.

In addition, in the fluorine gas production method and the fluorine gas production apparatus of this embodiment, "the accumulated energization amount from the time when the electrolytic solution is filled in the electrolytic cell and the electrolysis is started" means "only new electrolysis that has not been supplied to the electrolysis The accumulated energization amount from the start of electrolysis when the liquid is filled in the electrolytic cell and electrolysis is started". In addition, although the first runner and the second runner are separate runners, the first exterior and the second exterior may be separate places or the same place.

Here, an example of the fluorine gas production method and the fluorine gas production apparatus of this embodiment is shown. The first flow path is a flow path through which the fluid is transported from the inside of the electrolytic cell to the fluorine gas sorting part which selects and extracts fluorine gas from the fluid via the mist removal part which removes mist from the fluid. The second flow path is a flow path that transports fluid from the inside of the electrolytic cell to the fluorine gas selection part without passing through the mist removal part. That is, when the energization amount is greater than or equal to the preset reference value, the fluid is sent to the mist removal part provided in the first flow channel, and if the value is smaller than the preset reference value, the fluid is not sent to the mist. Remove the department. In this example, although the fluorine gas selection part is equivalent to the first exterior and the second exterior, the first exterior and the second exterior are the same place, but the first exterior and the second exterior may be separate locations.

In addition, the second flow path has a clogging suppression mechanism that suppresses clogging of the second flow path caused by mist droplets. The clogging suppression mechanism is not particularly limited as long as it is capable of suppressing the clogging of the second flow path caused by mist droplets, but examples include the following. That is, large-diameter pipes, inclined pipes, rotary screws, and air flow generators can be exemplified, and these can also be used in combination. In detail, it is possible to suppress clogging of the second flow channel due to mist droplets by configuring at least a part of the second flow channel with a pipe having a larger diameter than the first flow channel. In addition, it is possible to suppress clogging of the second flow channel due to mist droplets by forming at least a part of the second flow channel with a pipe that is inclined with respect to the horizontal direction and extends in a direction descending from the upstream side to the downstream side.

Furthermore, it is possible to suppress the clogging of the second flow channel due to the mist droplets by providing a rotary screw that transports the mist accumulated in the second flow channel toward the upstream or downstream side in the second flow channel. Furthermore, it is possible to suppress the clogging of the second flow channel caused by the mist droplets by providing the air flow generating device for the air flow for increasing the flow velocity of the fluid flowing in the second flow channel in the second flow channel. In addition, a mist removing section separate from the mist removing section provided in the first flow path may be provided in the second flow path as the clogging suppression mechanism.

The first flow channel removes the droplets from the fluid through the droplet removal part, so clogging caused by fog droplets is less likely to occur, and the second flow channel is provided with a clogging suppression mechanism so that clogging caused by droplets is less likely to occur. For this reason, the fluorine gas production method and fluorine gas production apparatus of the present embodiment can suppress clogging of pipes and valves caused by mist droplets when electrolyzing an electrolyte containing hydrogen fluoride and metal fluoride to produce fluorine gas. In addition, even if there is no droplet removal unit and clogging suppression mechanism, the piping that suppresses droplets can still be achieved by only switching the flow path through which the fluid flows to a separate flow path (first flow path or second flow path). , The clogging effect of the valve, but the above-mentioned effect is excellent when the mist removal part and the clogging suppression mechanism are provided.

In the following, the fluorine gas production method and the fluorine gas production apparatus of the present embodiment will be described in more detail. [Electrolyzer] The aspect of the electrolytic cell is not particularly limited, and any electrolytic cell can be used as long as the electrolytic solution containing hydrogen fluoride and metal fluoride can be electrolyzed to generate fluorine gas. Generally, the inside of the electrolytic cell is partitioned into an anode chamber where the anode is placed and a cathode chamber where the cathode is placed through a partition member such as a barrier wall. The fluorine gas generated at the anode and the hydrogen gas generated at the cathode are not mixed.

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

The electrolytic solution contains hydrogen fluoride and metal fluoride, and the type of the metal fluoride is not particularly limited. Preferably, it is a fluoride of at least one metal selected from potassium, cesium, rubidium, and lithium. When cesium or rubidium is contained in the electrolyte, the specific gravity of the electrolyte becomes larger, so the generation of mist droplets during electrolysis is suppressed.

As for 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 to potassium fluoride in the mixed molten salt of hydrogen fluoride and potassium fluoride can be set to, for example, hydrogen fluoride: potassium fluoride=1.5 to 2.5:1. Hydrogen fluoride: Potassium fluoride = KF·2HF in the case of 2:1 is a representative electrolyte, and the melting point of this mixed molten salt is about 72°C. Since this electrolyte is corrosive, it is preferable that the place where the electrolyte solution contacts, such as the inner surface of an electrolytic cell, is formed of metal, such as iron, nickel, and Monel alloy (trademark).

During the electrolysis of the electrolyte, a direct current is applied to the anode and the cathode, a gas containing fluorine gas is generated at the anode, and a gas containing hydrogen is generated at the cathode. In addition, there is a vapor pressure of hydrogen fluoride in the electrolyte, so the gases generated at the anode and cathode are accompanied by hydrogen fluoride, respectively. Furthermore, in the production of electrolyzed fluorine gas that permeates the electrolyte, the gas generated by the electrolysis contains mist of the electrolyte. Therefore, the gas phase part of the electrolytic cell is formed by the gas, hydrogen fluoride, and the mist droplets of the electrolytic solution generated by the electrolysis. Therefore, what is sent from the inside of the electrolytic cell to the outside is formed by the mist of gas, hydrogen fluoride, and electrolytic solution generated by electrolysis, and this is referred to as "fluid" in the present invention.

In addition, since the hydrogen fluoride in the electrolyte is consumed by the progress of electrolysis, a pipe for supplying hydrogen fluoride by continuously or intermittently supplying hydrogen fluoride to the electrolytic cell may be connected to the electrolytic cell. The supply of hydrogen fluoride can be supplied to the cathode chamber side of the electrolytic cell or to the anode chamber side. The main reasons for the generation of mist during the electrolysis of the electrolyte are as follows. The temperature of the electrolytic solution during electrolysis is adjusted to, for example, 80 to 100°C. The melting point of KF・2HF is 71.7°C, so the electrolyte is liquid when adjusted to the above temperature. The gas bubbles generated at the two electrodes of the electrolytic cell rise in the electrolyte and burst at the surface of the electrolyte. At this time, a part of the electrolyte is released into the gas phase.

The temperature of the gas phase is lower than the melting point of the electrolytic solution, so the released electrolytic liquid phase changes into a state like an extremely fine powder. The powder should be KF·nHF, a mixture of potassium fluoride and hydrogen fluoride. This powder is formed into mist droplets by the flow of other generated gas, and forms the fluid generated in the electrolytic cell. Such mist droplets have adhesiveness and other reasons, making it difficult to effectively remove them by general countermeasures such as the installation of filters.

In addition, although the amount of generation is small, the fine powder of the organic compound is sometimes generated as mist droplets due to the reaction between the carbonaceous electrode as the anode and the fluorine gas generated during electrolysis. In detail, there are many cases where contact resistance is generated in the power supply portion of the electric current to the carbonaceous electrode, and the temperature may be higher than the temperature of the electrolyte due to Joule heat. For this reason, the carbon forming the carbonaceous electrode reacts with fluorine gas, so that the coal-like organic compound CFx may be produced as mist droplets.

In addition, the electrolytic cell preferably has a structure in which bubbles generated at the anode or cathode used for electrolysis rise in the vertical direction in the electrolytic solution to reach the liquid surface of the electrolytic solution. When it has a structure in which the bubbles are difficult to rise in the vertical direction in the electrolyte and rise in a direction inclined with respect to the vertical direction, it is easy for a plurality of bubbles to gather to generate large bubbles. As a result, the large bubbles reach the liquid surface of the electrolyte and burst, so the amount of mist droplets tends to increase. When the bubbles rise in the vertical direction in the electrolyte to reach the liquid surface of the electrolyte, the small bubbles reach the liquid surface of the electrolyte and break, so the amount of mist tends to decrease.

[Average particle size measurement department] The fluorine gas production apparatus of the present embodiment may be provided with an average particle diameter measuring unit that measures the average particle diameter of the mist droplets included in the fluid, and this average particle diameter measuring unit can also measure the average particle diameter of light by using a light scattering method. The scatter detector is constructed. The light scattering detector can measure the average particle size of the mist droplets in the fluid flowing in the flow channel while continuously operating the fluorine gas production device, so it is preferable as the average particle size measuring section.

An example of a light scattering detector will be described with reference to FIG. 1. The light scattering detector of FIG. 1 is a light scattering detector that can be used as an average particle diameter measuring part in the fluorine gas production apparatus of this embodiment (for example, the fluorine gas production apparatus of FIGS. 2 and 4 to 13 described later). That is, when electrolyzing the electrolyte containing hydrogen fluoride and metal fluoride in the inside of the electrolytic cell of the fluorine gas production device to produce fluorine gas, the average of the droplets included in the fluid generated in the inside of the electrolytic cell Light scattering detector for particle size measurement. The light scattering detector can be connected to the fluorine gas production device, and the fluid is sent from the inside of the electrolytic cell to the light scattering detector to measure the average particle size of the droplets. It is also possible to connect the light scattering detector to the fluorine gas production device Next, the fluid was taken out from the inside of the electrolytic cell and introduced into a light scattering detector to measure the average particle size of the mist droplets.

The light scattering detector of Fig. 1 includes a sample chamber containing a fluid F 1. A light source that irradiates the fluid F in the sample chamber 1 with the light L for light scattering measurement 2. The light L for light scattering measurement is caused by the droplets in the fluid F. The scattered light detector 3 for detecting the scattered light S generated by the scattering of M, the transparent window 4A provided in the sample chamber 1 and in contact with the fluid F through which the light L for light scattering measurement penetrates, and the transparent window 4A provided in the sample chamber 1 to communicate with The transparent window 4B through which the fluid F contacts and the scattered light S penetrates. Transparent windows 4A, 4B are made _{of at least one selected from diamond, calcium fluoride (CaF 2} ), potassium fluoride (KF), silver fluoride (AgF), barium fluoride (BaF ₂ ), and potassium bromide (KBr) And formed.

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

The transparent windows 4A, 4B are in contact with the fluid F, but the fluid F contains highly reactive fluorine gas, so it is necessary to form the transparent windows 4A, 4B with a material that is not easily corroded by the fluorine gas. Regarding the material for forming the transparent windows 4A, 4B, for example, at least one selected from diamond, calcium fluoride, potassium fluoride, silver fluoride, barium fluoride, and potassium bromide. When the transparent windows 4A and 4B are formed of the above-mentioned material, deterioration due to contact with the fluid F can be suppressed.

In addition, for the transparent windows 4A and 4B, a coating film made of the above-mentioned material may be applied to the surface of glass such as quartz. The part in contact with the fluid F is coated with a film made of the above-mentioned material. Therefore, it is possible to suppress deterioration due to contact with the fluid F while reducing the cost. The transparent windows 4A and 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 general glass such as quartz. The material of the light scattering detector other than the transparent windows 4A and 4B is not particularly limited as long as it is a material having corrosion resistance to fluorine gas. It is preferable to use, for example, a copper-nickel alloy Monel alloy (trademark) , Herst alloy (trademark), stainless steel and other metal materials.

[Average particle size and energization amount of mist droplets] The inventors of the present invention measured the average particle diameter of the mist droplets generated during the production of the electrolyzed fluorine gas permeating the electrolyte solution using a light scattering detector. Illustrate an example of this result. The anode of the fluorine gas production device was exchanged with a new anode, the electrolysis cell was filled with new electrolyte, and electrolysis was started. The average particle size of the mist droplets in the fluid generated at the anode during a certain period of time immediately after the start of electrolysis was performed. Determination. As a result, the average particle size of the mist droplets was 0.5 to 2.0 μm. After that, the electrolysis is continued and after a sufficient time has passed, the electrolysis starts to stabilize, and the average particle diameter of the mist droplets in the fluid during this stable electrolysis is about 0.2 μm. In this way, during the period from immediately after the start of electrolysis to before the time of stable electrolysis, mist droplets with a relatively large particle size are generated. When the fluid containing large droplets immediately after the start of electrolysis flows through the pipes or valves, the droplets are adsorbed on the inner surfaces of the pipes and valves, and the pipes and valves are likely to be clogged.

In contrast, during stable electrolysis, the particle size of the mist droplets generated is relatively small. Such small droplets are not easy to settle or accumulate in the fluid, so they can flow stably through piping and valves. For this reason, during stable electrolysis, the possibility of clogging of piping and valves caused by the fluid formed by the mist droplets and the gas generated on the electrode is relatively low. In addition, the time from immediately after the start of electrolysis to the time of stable electrolysis is generally 25 hours or more and 200 hours or less. In addition, from immediately after the start of electrolysis to before the time of stable electrolysis, the electrolytic solution needs to be energized approximately 40 kAh or more per 1000 L.

In addition, the inventors found that there is a close relationship between the average particle size of the mist droplets and the amount of energization. Generally speaking, when only new electrolyte that has not been supplied to the electrolysis is filled in the electrolysis cell and the electrolysis is started, the mist droplets at the beginning of the electrolysis (that is, the amount of electricity accumulated from the beginning of the electrolysis is small) The average particle size is larger than 0.4 μm. After that, as the electrolysis continues (that is, as the accumulated energization amount from the beginning of the electrolysis increases), the average particle size of the mist droplets becomes smaller, and the energization amount becomes 0.4 μm or less when the electrolytic solution exceeds, for example, 60 kAh per 1000 L.

In this way, there is a correlation between the average particle size of the mist droplets and the energization amount. Therefore, the energization amount can be measured instead of the average particle size of the mist droplets during electrolysis, and the measurement result can be used to switch the flow channel. That is, as long as the accumulated energization amount is constantly measured from the beginning of electrolysis, and the result of the energization amount measurement is used at a predetermined point in the electrolysis, it is possible to appropriately switch based on the measurement result so that the amount of electricity generated by the electrolysis at the predetermined time point The flow path through which the fluid circulates.

Based on such findings, the inventors invented the above-mentioned fluorine gas production method and fluorine gas production apparatus having a structure that can switch the flow path through which the fluid flows in accordance with the amount of energization during electrolysis. The fluorine gas production apparatus of the present embodiment may have a first flow channel and a second flow channel, and a flow channel switching unit (for example, a switching valve) can be used to select a flow channel used for conveyance of the fluid from the two flow channels.

Alternatively, the fluorine gas production device of the present embodiment may also adopt a movement switching mechanism having two flow passages and movement and switching of the electrolytic cell, and the flow passage used for fluid transport is selected from the two flow passages to make the electrolysis The groove is moved to the vicinity of the flow channel and connected, thereby switching the flow channel. It has a first flow channel and a second flow channel as described above, so while one of the flow channels is blocked and cleaned, the other flow channel can still be opened to keep the fluorine gas production device operating.

Under the review of the present inventors, from immediately after the start of electrolysis to before the time of stable electrolysis, mist droplets with a relatively large average particle size are generated. Therefore, at this time, the fluid can be sent to the second flow channel with a clogging suppression mechanism. . As time elapses, when stable electrolysis is reached, mist droplets with a relatively small average particle size are generated, so at this time, the flow channel can be switched to send the fluid to the first flow channel with the mist removal part. Such switching of the flow channel is performed in accordance with the measured energization amount during electrolysis, but the switching of the flow channel is performed based on a preset reference value. The appropriate reference value for the average particle diameter of the mist droplets generated on the anode varies depending on the device, but is, for example, 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, based on the correlation between the average particle diameter of the mist droplets and the energization amount, the lower limit of the appropriate reference value for the energization amount is 40 kAh or more per 1000 L of the electrolyte, preferably 50 kAh or more. In addition, the upper limit of the above-mentioned reference value is preferably 100 kAh or less, and more preferably 80 kAh or less. The most appropriate reference value of the energization amount is 60kAh. When the energization amount is smaller than the reference value, the fluid can be sent to the second flow channel, and when the energization amount is greater than the reference value, the fluid can be sent to the first flow channel.

The energization amount is the product of the current value and the time, so the cumulative energization amount during electrolysis can be measured using, for example, an ammeter, a timing device, and a calculation device. That is, the current supplied to the electrode for electrolysis is measured by an ammeter, and the total electrolysis time from the start of electrolysis is measured by a timekeeping device such as a clock, and these values are multiplied by a calculation device such as a computer to obtain the electrolysis. The accumulated energization amount at the time. In addition, a coulometer can also be used to measure the accumulated energization amount during electrolysis. In addition, in the fluid generated at the cathode (the main component is hydrogen gas), for example, the powder contains 20-50μg per unit volume (1 liter) (the specific gravity of the mist droplets is calculated assuming 1.0g/mL). The average particle size is about 0.1 μm, with a distribution of ±0.05 μm.

Regarding the fluid generated at the cathode, a large difference in the particle size distribution of the generated powder has not been confirmed depending on the amount of energization. The average particle size of the mist droplets contained in the fluid generated at the cathode is smaller than the mist droplets contained in the fluid generated at the anode. Therefore, compared with the mist droplets contained in the fluid generated at the anode, it is not easy to cause piping and valve damage. block. Therefore, the mist contained in the fluid generated at 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. Although the fluorine gas production apparatus of FIG. 2 is an example with two electrolytic cells, the electrolytic cell may be one, three or more, or, for example, 10-15. The fluorine gas production apparatus shown in FIG. 2 includes electrolytic cells 11, 11 that contain an electrolytic solution 10 inside and perform electrolysis, an anode 13 that is arranged in the electrolytic cell 11 and is immersed in the electrolytic solution 10, and an anode 13 that is arranged in the electrolytic cell 11 The inside is a cathode 15 immersed in the electrolytic solution 10 and arranged to face the anode 13.

The inside of the electrolytic cell 11 is partitioned into an anode chamber 22 and a cathode chamber 24 by a barrier wall 17 extending vertically downward from the top surface of the inside of the electrolytic cell 11 and immersed in the electrolyte 10 at the lower end. In addition, the anode 13 is arranged in the anode chamber 22 and the cathode 15 is arranged in the cathode chamber 24. Among them, 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 barrier wall 17, and the portion of the electrolyte 10 above the lower end of the barrier wall 17 is increased by The barrier rib 17 is separated, and the portion below the lower end of the barrier rib 17 in the electrolytic solution 10 is not directly separated by the barrier rib 17 but is continuous.

In addition, the fluorine gas production apparatus shown in FIG. 2 is provided with a first average particle diameter measuring unit 31 that measures the average particle diameter of the mist droplets contained in the fluid generated in the electrolytic cell 11 during the electrolysis of the electrolyte 10 , The first droplet removal section 32 that removes the droplets from the fluid, the fluorine gas selection section (not shown) that selects the fluorine gas from the fluid and the fluorine gas selection section (not shown), and the flow that sends the fluid from the inside of the electrolytic cell 11 to the fluorine gas selection section road.

In addition, the fluorine gas production device shown in FIG. 2 includes an ammeter (not shown) that measures the current supplied to the anode 13 and the cathode 15 for electrolysis, and a timer (not shown) that measures the total electrolysis time since the start of electrolysis. ), and a calculation device (not shown) that multiplies the current value measured with an ammeter by the total electrolysis time measured with a timepiece to calculate the accumulated energization amount during electrolysis. Such an ammeter, a timekeeping device, and a calculation device constitute the energization amount measuring unit which is a constituent element of the present invention.

In addition, the above-mentioned flow channel has a first flow channel that sends fluid from the inside of the electrolytic cell 11 to the fluorine gas selection section through the first droplet removal section 32, and removes the fluid from the electrolysis without passing through the first droplet removal section 32. The inside of the tank 11 is sent to the second flow path of the fluorine gas selection unit. In addition, this flow channel has a flow channel switching unit that switches the flow channel through which the fluid flows to the first flow channel or the second flow channel in accordance with the energization amount measured by the aforementioned energization amount measuring unit. That is, a flow channel switching section is provided in the middle of the flow channel extending from the electrolytic cell 11, and the flow channel through which the fluid flows can be changed by the flow channel switching section.

This channel switching unit sends fluid from the inside of the electrolytic cell 11 to the first channel when the energization amount measured by the energization amount measuring unit is greater than or equal to the preset reference value. When it is small, the fluid is sent from the inside of the electrolytic cell 11 to the second flow path. In addition, the second flow path has a clogging suppression mechanism that suppresses clogging caused by droplets of the second flow path.

That is, in the case where the energization amount measured by the energization amount measuring unit is equal to or greater than the reference value, the electrolytic cell 11 is connected to the fluorine gas selection unit and the fluid is sent to the first mist removal unit 32 provided. In the flow path, when the energization amount measured by the energization amount measuring unit is smaller than the reference value, the electrolytic cell 11 is connected to the fluorine gas selection unit and the fluid is sent to the second flow path provided with the clogging suppression mechanism.

For 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 removing device, that is, the method of removing mist is not particularly limited. However, the average particle size of the mist is small, so that, for example, an electrostatic dust collector, a vent scrubber, and a filter can be used as the mist removing device.

Among the above-mentioned mist removing devices, the mist removing device shown in FIG. 3 is preferably used. The mist removing device shown in FIG. 3 is a scrubber-type mist removing device using liquid hydrogen fluoride as a circulating liquid. The mist removing device shown in FIG. 3 can efficiently remove mist drops having 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 preferable to cool the circulating fluid in order to reduce the concentration of hydrogen fluoride in the fluorine gas. Therefore, 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 first piping 41 that sends the fluid generated in the anode chamber 22 of the electrolytic cell 11 (hereinafter, sometimes referred to as "anode gas") to the outside connects the electrolytic cell 11 and the fourth piping 44, from the two electrolytic cells 11, The anode gas sent by 11 passes through the first pipe 41 and is sent to the fourth pipe 44 to be mixed. In addition, the main component of the anode gas is fluorine gas, and the secondary components are droplets, hydrogen fluoride, carbon tetrafluoride, oxygen, and water.

The fourth pipe 44 is connected to the first droplet removal section 32, and the anode gas is sent to the first droplet removal section 32 through the fourth pipe 44, so the droplets and hydrogen fluoride in the anode gas are passed through the first droplet removal section 32. Remove the gas from the anode. The anode gas from which the mist droplets and hydrogen fluoride are removed passes through the sixth pipe 46 connected to the first mist droplet removal section 32 and is sent from the first mist droplet removal section 32 to a fluorine gas selection section not shown. Then, the fluorine gas is selected and taken out from the anode gas through the fluorine gas selection unit.

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

The cathode chamber 24 of the electrolytic cell 11 is also the same as the anode chamber 22. In other words, the second pipe 42 that sends the fluid generated in the cathode chamber 24 of the electrolytic cell 11 (hereinafter, sometimes referred to as "cathode gas") to the outside connects the electrolytic cell 11 and the fifth pipe 45, from the two electrolytic cells The cathode gas sent from the tanks 11 and 11 passes through the second pipe 42 and is sent to the fifth pipe 45 to be mixed. In addition, the main component of the cathode gas is hydrogen, and the secondary components are droplets, hydrogen fluoride, and water.

The cathode gas contains fine mist droplets and 5-10% by volume of hydrogen fluoride, so it is not preferable to discharge it directly into the atmosphere. For this reason, the fifth pipe 45 is connected to the second mist removal section 33, the cathode gas is sent to the second mist removal section 33 through the fifth pipe 45, and the mist and hydrogen fluoride in the cathode gas pass through the second mist removal section 33 is removed from the cathode gas. The cathode gas from which the mist and hydrogen fluoride are removed passes through the seventh pipe 47 connected to the second mist removal section 33 and is discharged from the second mist removal section 33 to the atmosphere. The type of the second mist removing unit 33, that is, the method of removing mist is not particularly limited, but a scrubber-type mist removing device using an alkaline aqueous solution for the circulating liquid can be used.

Although the pipe diameters and installation directions of the first pipe 41, the second pipe 42, the fourth pipe 44, and the fifth pipe 45 (the direction in which the pipe extends are, for example, the vertical direction or the horizontal direction) are not particularly limited, the first pipe 41 is The second pipe 42 and the second pipe 42 are preferably arranged to extend in the vertical direction from the electrolytic cell 11. The flow velocity of the fluid flowing through the first pipe 41 and the second pipe 42 is set to a pipe diameter of 30 cm/sec or less in the standard state. . In this way, even if the mist included in the fluid falls due to its own weight, the mist still sinks into the electrolytic cell 11. Therefore, it is unlikely that the powder may cause internal damage to the first pipe 41 and the second pipe 42. block. In addition, the fourth pipe 44 and the fifth pipe 45 are preferably provided so as to extend in the horizontal direction, and it is assumed that the flow velocity of the fluid flowing through the fourth pipe 44 and the fifth pipe 45 becomes faster as the first pipe 41 and the second pipe 41 and the second pipe. The pipe diameter is about 1 to 10 times the pipe diameter in the case of the pipe 42.

In addition, 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 pipe 52 communicates the electrolytic cell 11 with the first bypass pipe 51, and the anode gas sent from the two electrolytic cells 11, 11 is sent to the first bypass pipe 51 through the second bypass pipe 52 And mixed. Furthermore, through the first bypass pipe 51, the anode gas is sent to a fluorine gas selection unit (not shown). Then, the fluorine gas is selected and taken out from the anode gas through the fluorine gas selection unit. In addition, the fluorine gas selection part connected to the first bypass pipe 51 and the fluorine gas selection part connected to the sixth pipe 46 may be the same or different.

Although the pipe diameter and installation direction of the second bypass pipe 52 are not particularly limited, the second bypass pipe 52 is preferably installed so as to extend in the vertical direction from the electrolytic cell 11 and is set to flow through the second bypass pipe. The flow rate of the fluid of 52 is a pipe diameter of 30 cm/sec or less in the standard state.

In addition, the first bypass pipe 51 is provided so as to extend in the horizontal direction. In addition, the first bypass pipe 51 is a pipe having a larger diameter than the fourth pipe 44, and the pipe diameter of the first bypass pipe 51 is such that clogging of the first bypass pipe 51 due to the accumulation of powder is unlikely to occur. the size of. The first bypass pipe 51 is a pipe having a larger diameter than the fourth pipe 44 and constitutes a clogging suppression mechanism. The diameter of the first bypass pipe 51 is preferably more than 1.0 times and 3.2 times or less than that 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 understood from the above description, the first pipe 41 and the fourth pipe 44 constitute the above-mentioned first flow passage, and the first bypass pipe 51 and the second bypass pipe 52 constitute the above-mentioned second flow passage. In addition, a clogging 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. In addition, by switching the first piping valve 61 to the open state or the closed state, it is possible to control the availability of anode gas supply from the electrolytic cell 11 to the first mist removal unit 32. In addition, a bypass valve 62 is provided in the second bypass pipe 52, respectively. In addition, by switching the bypass valve 62 to the open state or the closed state, it is possible to control whether the anode gas can be supplied from the electrolytic cell 11 to the first bypass pipe 51.

In addition, between the electrolytic cell 11 and the first mist removal part 32, in the middle part of the fourth pipe 44 and downstream of the connection part with the first pipe 41, a first average particle size measurement is provided.部31. Then, the average particle diameter of the mist included in the anode gas flowing through the fourth pipe 44 is measured by the first average particle diameter measuring unit 31. In addition, the fluorine gas and nitrogen gas included in the anode gas after measuring the average particle diameter of the mist droplets are analyzed, so that the current efficiency in the production of the fluorine gas can be measured.

In addition, the same second average particle size measuring part 34 is also provided in the middle part of the first bypass pipe 51 and downstream of the connecting part with the second bypass pipe 52, and the same second average particle size measuring part 34 is measured through the second average particle size measuring part 34. The average particle diameter of the mist droplets included in the anode gas flowing through the first bypass pipe 51. 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.

In addition, the fluorine gas production apparatus shown in FIG. 2 includes a energization amount measuring unit as described above. The location of the energization measuring unit is not particularly limited. For example, it can be installed in the electrolytic cell 11, but as long as it can measure the current supplied to the anode 13 and the cathode 15 for electrolysis and the total electrolysis time since the start of electrolysis, and calculate the total amount of electrolysis. The amount of energization can also be set anywhere in the fluorine gas production device. In addition, the ammeter, the timing device, and the calculation device that constitute the energization amount measurement unit may be integrated, or may be of different shapes individually.

The energization amount measurement unit measures the cumulative energization amount during electrolysis. If the measurement result is less than the preset reference value, the bypass valve 62 is opened to send the anode gas from the electrolytic cell 11 to the first bypass. In the piping 51, the first piping valve 61 is closed at the same time, so that the anode gas is not sent to the fourth piping 44 and the first mist removal unit 32. That is, the anode gas is sent to the second flow channel.

On the other hand, when the measurement result is greater than or equal to the preset reference value, the first piping valve 61 is opened, the anode gas is sent to the fourth piping 44 and the first droplet removal part 32, and the bypass valve 62 is in the closed state so that anode gas is not sent from the electrolytic cell 11 to the first bypass pipe 51. That is, the anode gas is sent to the first flow channel. As can be understood from the above description, the first piping valve 61 and the bypass valve 62 constitute the above-mentioned flow path switching section. As described above, the fluorine gas production apparatus is operated while switching the flow channel according to the accumulated energization amount during electrolysis, so that the smooth continuous operation can be performed while suppressing clogging of the pipes and valves caused by mist droplets. Therefore, when the fluorine gas production apparatus shown in FIG. 2 is followed, fluorine gas can be produced economically.

For example, in the mist removal part, it is okay to prepare a plurality of piping provided with filters, switch them as appropriate, exchange the filters, and perform electrolysis. Furthermore, it is possible to determine the period during which the filter should be frequently exchanged and the period during which the filter should not be frequently exchanged based on the measurement of the accumulated energization amount during the electrolysis. In addition, when the switching frequency of the pipe through which the fluid flows is appropriately adjusted based on the above judgment, the operation of the fluorine gas production apparatus can be continued efficiently.

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. In the fluorine gas production apparatus shown in FIG. 2, the electrolytic cell 11 and the first bypass pipe 51 are connected to the second bypass pipe 52. In the fluorine gas production apparatus of the first modification shown in FIG. 4, the second The bypass pipe 52 connects the first pipe 41 and the first bypass pipe 51. The configuration of the fluorine gas production apparatus of the first modification example is substantially the same as that of the fluorine gas production apparatus of FIG. 2 except for the above-mentioned points, so 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 example shown in FIG. 5 is an example provided with one electrolytic cell 11. The first average particle size measuring unit 31 is provided in the first pipe 41 instead of the fourth pipe 44 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 passing through the second bypass pipe 52.

In addition, since the first bypass pipe 51 has a larger diameter than the fourth pipe 44, it functions as a clogging suppression mechanism. Furthermore, for example, by providing a space for mist accumulation at the downstream end of the first bypass pipe 51, the effect of suppressing clogging can be further increased. As for the space for the accumulation of mist droplets, for example, the downstream end portion of the first bypass pipe 51 is formed in a pipe diameter larger than the central portion in the installation direction (for example, the pipe diameter of the central portion in the installation direction is 4 times or more). The space formed by forming the downstream end portion of the first bypass pipe 51 into a container-shaped space can pass through the space for mist accumulation, thereby suppressing clogging of the first bypass pipe 51. This is for the purpose of the blocking prevention effect due to the large cross-sectional area of the flow channel and the blocking prevention effect using the gravity drop of the mist due to the decrease in the linear velocity of the gas flow. In addition, the bypass valve 62 is provided in the third bypass pipe 53 that connects the first bypass pipe 51 and the fluorine gas selection unit not shown. The configuration of the fluorine gas production apparatus of the second modification example is substantially the same as that of the fluorine gas production apparatus of FIG. 2 except for the above-mentioned points, so 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 apparatus of the third modification example, the first average particle size measuring section 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 size measuring section 31, and the mist is removed. Determination of average particle size. The fluorine gas production apparatus of the third modification example does not include the second average particle size measuring unit 34. The configuration of the fluorine gas production apparatus of the third modification example is substantially the same as that of the fluorine gas production apparatus of the second modification example except for the above-mentioned points, so 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 example is a different example from the second modification example shown in FIG. 5 in the clogging suppression mechanism. In the fluorine gas production apparatus of the second modification example, the first bypass pipe 51 is provided so as to extend in the horizontal direction. In the fluorine gas production apparatus of the fourth modification example, the first bypass pipe 51 is inclined with respect to the horizontal direction. And it extends in the descending direction from the upstream side to the downstream side. Due to this inclination, the accumulation of powder in the first bypass pipe 51 is suppressed. The greater the inclination, the greater the effect of suppressing the accumulation of powder.

The inclination angle of the first bypass pipe 51 is preferably 30 degrees or more within a range where the depression angle from the horizontal plane is smaller than 90 degrees, and more preferably 40 degrees or more and 60 degrees or less. When clogging of the first bypass pipe 51 may occur, by hammering the inclined first bypass pipe 51, the deposits in the first bypass pipe 51 can easily move, and the clogging can be avoided. The configuration of the fluorine gas production apparatus of the fourth modification example is substantially the same as that of the fluorine gas production apparatus of the second modification example except for the above-mentioned points, so 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 an example that is different from the third modification shown in FIG. 6 in the clogging suppression mechanism. In the fluorine gas production apparatus of the third modification, the first bypass pipe 51 is provided so as to extend in the horizontal direction. In the fluorine gas production device of the fifth modification, the first bypass pipe 51 is inclined with respect to the horizontal direction. And it extends in the descending direction from the upstream side to the downstream side. Due to this inclination, the accumulation of powder in the first bypass pipe 51 is suppressed. The preferable inclination angle of the first bypass pipe 51 is the same as in the case of the fourth modification described above. The configuration of the fluorine gas production apparatus of the fifth modification example is substantially the same as that of the fluorine gas production apparatus of the third modification example except for the above-mentioned points, so 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 example is a different example in the structure of the electrolytic cell 11 from the second modification example shown in FIG. 5. The electrolytic cell 11 has an anode 13 and two cathodes 15 and 15, and is partitioned into an anode compartment 22 and a cathode compartment 24 through a cylindrical barrier wall 17 surrounding one anode 13. The anode chamber 22 is formed to extend 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 substantially the same as that of the fluorine gas production apparatus of the second modification example except for the above-mentioned points, so 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 an example that is different from the sixth modification shown in FIG. 9 in the structure of the first bypass pipe 51. That is, in the fluorine gas production apparatus of the seventh modification, the first bypass pipe 51 is inclined with respect to the horizontal direction as in the fourth modification and the fifth modification, and extends in a direction descending from the upstream side to the downstream side. The preferable inclination angle of the first bypass pipe 51 is the same as in the case of the fourth modification described above. The configuration of the fluorine gas production device of the seventh modification example is substantially the same as that of the fluorine gas production device of the sixth modification example except for the above-mentioned points, so 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 an example that is different from the second modification shown in FIG. 5 in the clogging suppression mechanism. In the fluorine gas production apparatus of the eighth modification, the rotary screw 71 constituting the clogging suppression mechanism is provided inside the first bypass pipe 51. This rotating screw 71 is arranged such that its rotating shaft is parallel to the longitudinal direction of the first bypass pipe 51.

In addition, the motor 72 can rotate the rotary screw 71 to send the mist accumulated in the first bypass pipe 51 to the upstream side or the downstream side. According to this, the accumulation of powder in the first bypass pipe 51 is suppressed. The configuration of the fluorine gas production apparatus of the eighth modification example is substantially the same as that of the fluorine gas production apparatus of the second modification example except for the above-mentioned points, so 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 an example different from the second modification shown in FIG. 5 in the clogging suppression mechanism. In the fluorine gas production apparatus of the ninth modification, the air flow generating device 73 constituting the clogging suppression mechanism is provided in the first bypass pipe 51. The gas flow generator 73 sends a gas flow (for example, a gas flow of nitrogen) from the upstream side of the first bypass pipe 51 to the downstream side, and increases the flow velocity of the anode gas flowing in the first bypass pipe 51. According to this, the accumulation of powder in the first bypass pipe 51 is suppressed.

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 may be greater than 10 m/sec, in this case, the pressure loss due to the pipe resistance in the first bypass pipe 51 increases, and the pressure in the anode chamber 22 of the electrolytic cell 11 increases. The pressure in the anode chamber 22 and the pressure in the cathode chamber 24 are preferably approximately the same. When the difference between the pressure in the anode chamber 22 and the pressure in the cathode chamber 24 becomes too large, the anode gas exceeds the barrier wall 17 and flows into the cathode chamber. 24. The reaction between fluorine gas and hydrogen gas may sometimes cause obstacles to the generation of fluorine gas. The configuration of the fluorine gas production apparatus of the ninth modification example is substantially the same as that of the fluorine gas production apparatus of the second modification example except for the above-mentioned points, so 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 size 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 size measuring unit 31, and the mist Determination of average particle size. The fluorine gas production apparatus of the tenth modification does not include the second average particle size measuring unit 34. The configuration of the fluorine gas production apparatus of the tenth modification example is substantially the same as that of the fluorine gas production apparatus of the ninth modification example shown in FIG. 12 except for the above-mentioned points, so the description of the same parts is omitted. [Example]

Examples and comparative examples are shown below to describe the present invention more specifically. [Reference Example 1] The electrolytic solution was electrolyzed to produce fluorine gas. For the electrolyte, a mixed molten salt (560L) of 434kg of hydrogen fluoride and 630kg of potassium fluoride was used. For the anode, an amorphous carbon electrode (30 cm wide, 45 cm long, 7 cm thick) manufactured by SGL Carbon was used, and 16 anodes were installed in the electrolytic cell. In addition, a stamped plate made of Monel alloy (trademark) was used for the cathode, and it was installed in the electrolytic cell. Two cathodes face one anode, and the total area of the part of one anode facing the cathode is 1736 cm ² .

The electrolysis temperature is controlled at 85～95℃. First, the temperature of the electrolyte was set to 85°C, and a direct current of 1000 A was applied ^{at a current density of 0.036 A/cm 2 to start electrolysis.} The water concentration in the electrolyte at this time was 1.0% by mass. In addition, the water concentration is measured by Karl Fischer analysis method. The electrolysis under the above-mentioned conditions was started, and a small plug noise was observed in the vicinity of the anode in the anode chamber during the period from immediately after the start of the electrolysis before the accumulated energization amount reached 10 kAh. This stop sound should be caused by the reaction between the generated fluorine gas and the moisture in the electrolyte.

In this state, the fluid generated at the anode is sent from the anode chamber of the electrolytic cell to the outside for extraction, and the mist included in the fluid is analyzed. As a result, the fluid generated at the anode contains 5.0 to 9.0 mg of powder per 1 L (the specific gravity of the mist is calculated assuming 1.0 g/mL, and the same applies hereinafter), and the average particle size of the powder is 1.0 to 2.0 μm. As a result of observing this powder with an optical microscope, the powder having a shape that hollowed out the inside of a ball was mainly observed. In addition, the current efficiency of fluorine gas generation at this time is 0 to 15%.

Furthermore, when the electrolysis is continued until the accumulated energization amount reaches 30 kAh, the frequency of the plug sound generated in the anode chamber gradually decreases. The water concentration in the electrolyte at this time was 0.7% by mass. In addition, in this state, the fluid generated at the anode is sent from the anode chamber of the electrolytic cell to the outside for extraction, and the mist included in the fluid is analyzed. As a result, the fluid generated at the anode contains 0.4 to 1.0 mg of mist droplets per 1 L, and the average particle size of the mist droplets is 0.5 to 0.7 μm. Furthermore, the current efficiency of fluorine gas generation at this time is 15 to 55%. The stage from the start of electrolysis to the previous electrolysis is referred to as "stage (1)".

Furthermore, the subsequent stage (1) continues the electrolysis of the electrolyte. At this time, the hydrogen fluoride is consumed and the level of the electrolyte is reduced, so the hydrogen fluoride is supplied from the hydrogen fluoride tank to the electrolytic tank as appropriate. The water concentration in the supplied hydrogen fluoride is 500 mass ppm or less. Furthermore, when the accumulated energization amount exceeds 60 kAh by continuing the electrolysis, the average particle diameter of the mist droplets contained in the fluid generated at the anode is 0.36 μm (that is, 0.4 μm or less). At this point, no plosive sound was generated in the anode chamber at all. In addition, the water concentration in the electrolyte solution at this time is 0.2% by mass (that is, 0.3% by mass or less). Furthermore, the current efficiency of fluorine gas generation at this time is 65%. The end point of stage (1) to the stage of electrolysis so far is referred to as "stage (2)".

Furthermore, the current is increased to 3500A, the current density is increased to 0.126A/cm ² , and the subsequent stage (2) continues the electrolysis of the electrolyte. In this state, the fluid generated at the anode is sent from the anode chamber of the electrolytic cell to the outside for extraction, and the mist included in the fluid is analyzed. As a result, the fluid generated at the anode contains 0.03 to 0.06 mg of powder per 1 L. The average particle size of the powder is about 0.2 μm (0.15 to 0.25 μm), and the particle size has a distribution of about 0.1 to 0.5 μm. Fig. 14 shows the measurement result of the particle size distribution of this powder. Furthermore, the current efficiency of fluorine gas generation at this time was 94%. The end of stage (2) to the stage of electrolysis up to now is the "stable stage".

Table 1 summarizes the contents of the electrolysis of Reference Example 1 performed as described above. In Table 1, the same current, electrolysis elapsed time, energization amount, water concentration in the electrolyte, and the mass of droplets contained in the fluid generated at the anode (denoted as "anode gas" in Table 1) 1L, droplets The average particle size and current efficiency also show the amount of fluid (containing fluorine gas, oxygen, and droplets) generated at the anode, the amount of droplets generated at the anode, the intensity of the stop sound, and the amount of fluid generated at the cathode Water concentration (denoted as "water concentration in cathode gas" in Table 1).

In addition, a graph plotting the relationship between the average particle size of the mist droplets and the amount of mist droplets generated at the anode is shown in FIG. 15. From the graph of FIG. 15, it is known that there is a correlation between the average particle size of the mist droplets and the amount of mist droplets generated at the anode. The larger the amount of mist droplets, the more likely it is that pipes and valves will be clogged. In addition, when mist droplets with an average particle size larger than 0.4 μm are generated, the amount of mist droplets generated will increase, and the amount of mist will be deposited due to gravity. It can be said that the relationship of the graph shown in FIG. 15 shows the correlation between the average particle size of the mist droplets and the ease of occurrence of clogging of piping and valves. In addition, a graph showing the relationship between the average particle size of the mist droplets and the accumulated energization amount is shown in FIG. 16. The larger the average particle diameter of the mist droplets, the more likely it is to cause clogging of piping and valves. Therefore, the relationship of the graph shown in FIG. 16 can be said to indicate the correlation between the cumulative amount of energization and the ease of occurrence of clogging of piping and valves.

[Example 1] The electrolysis as in Reference Example 1 was performed using the fluorine gas production apparatus shown in FIG. 2. In the electrolysis in the stage (1), the fluid generated at the anode is circulated through the second bypass pipe, the bypass valve, and the first bypass pipe. After the electrolysis of stage (1) is completed, the electrolysis is temporarily stopped, and the inside of the fluorine gas production apparatus is inspected. As a result, only the pipe was deposited with mist in the first bypass pipe, but the pipe diameter was made thick, so that the pipe clogging did not occur.

The average particle size of the droplets becomes 0.4μm or less (the accumulated energization amount is 60kAh of the reference value) of electrolysis in stage (2), so the fluid generated at the anode passes through the first pipe, the first pipe valve, The fourth pipe and the first mist removal part circulate. No accumulation or clogging of droplets occurred in the first pipe, the first pipe valve, and the fourth pipe, and the fluid generated at the anode was supplied to the first droplet removal section, so the droplets were removed in the first droplet removal section. The first mist removing section is a scrubber-type removing section that ejects liquid hydrogen fluoride to remove fine particles such as mist droplets, and the mist droplet removal rate is 98% or more.

[Comparative Example 1] In the electrolysis of stage (1), except for the point where the fluid generated at the anode circulates through the first piping, the first piping valve, the fourth piping, and the first droplet removal part, it is the same as in Example 1 Perform electrolysis. In the electrolysis of stage (1), the measured value of the pressure gauge on the anode side among the pressure gauges installed on the anode side and the cathode side of the electrolytic cell gradually increases, and the pressure difference with the cathode side becomes 90mmH ₂ O, so stop electrolysis. The reasons for the suspension are as follows. The vertical length (immersion depth) of the part of the barrier wall in the electrolytic cell that is immersed in the electrolyte is 5 cm. Therefore, when the pressure on the anode side becomes about 100 mmH ₂ O higher than the pressure on the cathode side, the liquid of the electrolyte on the anode side The surface change is lower than the lower end of the barrier wall. As a result, the fluorine gas crosses the barrier wall and mixes with the hydrogen gas on the cathode side, causing a rapid reaction between the fluorine gas and the hydrogen gas, which is very dangerous.

After purging the system with nitrogen gas, etc., the internals of the first pipe, the first pipe valve, and the fourth pipe were inspected. As a result, the first pipe was a pipe extending in the vertical direction, so it was not clogged. A small amount of powder adheres to the first piping valve, and the downstream piping of the first piping valve, that is, the inlet to the fourth piping is blocked by the powder. There is also accumulation of powder in the fourth piping, but it is not the amount that blocks the piping.

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 size measurement section 32: The first mist removal part 33: The second droplet removal part 34: The second average particle size measurement section 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 pipe 52: 2nd bypass pipe 61: The first piping valve 62: Bypass valve F: fluid L: Light for light scattering measurement M: fog drop S: scattered light

Fig. 1 is a schematic diagram for explaining an example of a light scattering detector used as an average particle size measuring unit in a fluorine gas production apparatus according to an embodiment of the present invention. [Fig. 2] Fig. 2 is a schematic diagram for explaining an example of a fluorine gas production apparatus according to an embodiment of the present invention. [Fig. 3] Fig. 3 is a schematic diagram for explaining an example of a mist removing device used as a mist removing section in the fluorine gas production apparatus of Fig. 2. Fig. 4 is a schematic diagram explaining a first modification of the fluorine gas production apparatus of Fig. 2. [Fig. 5] Fig. 5 is a schematic diagram for explaining a second modification of the fluorine gas production apparatus of Fig. 2. [Fig. 6] Fig. 6 is a schematic diagram for explaining a third modification of the fluorine gas production apparatus of Fig. 2. [Fig. 7] Fig. 7 is a schematic diagram for explaining a fourth modification of the fluorine gas production apparatus of Fig. 2. [Fig. 8] Fig. 8 is a schematic diagram for explaining a fifth modification of the fluorine gas production apparatus of Fig. 2. [Fig. 9] Fig. 9 is a schematic diagram for explaining a sixth modification of the fluorine gas production apparatus of Fig. 2. [Fig. 10] Fig. 10 is a schematic diagram for explaining a seventh modification of the fluorine gas production apparatus of Fig. 2. Fig. 11 is a schematic diagram explaining an eighth modification of the fluorine gas production apparatus of Fig. 2. [Fig. 12] Fig. 12 is a schematic diagram for explaining a ninth modification of the fluorine gas production apparatus of Fig. 2. Fig. 13 is a schematic diagram for explaining a tenth modification of the fluorine gas production apparatus of Fig. 2. [Fig. 14] is a graph showing the particle size distribution of the mist droplets included in the fluid generated at the anode in Reference Example 1. [Fig. [Figure 15] is a graph showing the correlation between the average particle size of the mist droplets and the amount of mist droplets generated at the anode in Reference Example 1. [Fig. 16] is a graph showing the relationship between the average particle size of the droplets and the energization amount in Reference Example 1. [Fig.

10: Electrolyte

11: Electrolyzer

13: anode

15: Cathode

17: Barrier

22: anode chamber

24: Cathode chamber

31: The first average particle size measurement section

32: The first mist removal part

33: The second droplet removal part

34: The second average particle size measurement section

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 pipe

52: 2nd bypass pipe

61: The first piping valve

62: Bypass valve

Claims (5)

A method for producing fluorine gas by electrolyzing an electrolyte containing hydrogen fluoride and metal fluoride to produce fluorine gas, It has: Perform the electrolysis procedure of the aforementioned electrolysis in an electrolytic cell, The energization amount measurement program for measuring the accumulated energization amount since the electrolytic solution is filled into the electrolytic cell and the electrolysis is started, and A gas supply process in which the fluid generated inside the electrolytic cell during the electrolysis of the electrolytic solution is transported from the inside of the electrolytic cell to the outside via a flow channel, Wherein, in the air supply program, the flow path through which the fluid circulates is switched according to the energization amount measured in the energization amount measurement program, and the energization amount measured in the energization amount measurement program is a preset reference If the value is greater than the value, the fluid is fed to the first flow path that feeds the fluid from the inside of the electrolytic cell to the first outside. If the fluid is smaller than the preset reference value, 2 The second flow channel for externally transporting the aforementioned fluid transports the aforementioned fluid, The aforementioned predetermined reference value is a value within the range of 40 kAh or more per 1000 L of the aforementioned electrolyte. The method for producing fluorine gas according to claim 1, wherein the metal fluoride is at least one metal fluoride 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 a carbon formed of at least one carbon material selected from diamond, diamond-like carbon, amorphous carbon, graphite, and glassy carbon质electrode. The method for producing fluorine gas according to any one of claims 1 to 3, wherein the electrolytic cell has air bubbles generated at the anode or cathode used in the electrolysis rising in the vertical direction in the electrolytic solution and reaching the electrolysis The structure of the liquid surface. A fluorine gas production device that produces fluorine gas by electrolyzing an electrolyte solution containing hydrogen fluoride and metal fluoride, It has: An electrolytic cell that contains the foregoing electrolyte and performs the foregoing electrolysis, A energization amount measuring unit that measures the accumulated energization amount since the electrolytic solution is filled in the electrolytic cell and the electrolysis is started, and A flow channel that transports the fluid generated inside the electrolytic cell during the electrolysis of the electrolytic solution from the inside of the electrolytic cell to the outside, Among them, 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 also has a energization dependent on the above. The energization amount measured by the quantity measuring section switches the flow path through which the fluid flows to the flow path switching section for the first flow path or the second flow path, In the case where the energization amount measured by the energization amount measuring unit is equal to or greater than a preset reference value, the flow path switching unit transports the fluid from the inside of the electrolytic cell to the first flow path, which is higher than the preset value. When the reference value of is small, transport the fluid from the inside of the electrolytic cell to the second flow path, The aforementioned predetermined reference value is a value within the range of 40 kAh or more per 1000 L of the aforementioned electrolyte.

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