JPH0570716B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a gas separation module capable of electrolyzing aqueous solutions and purifying and separating gases.

"Conventional technology" Electrolyzers used for electrolysis of aqueous solutions, etc.
Conventionally, it has been composed of a container in which a solution is stored, a cathode and an anode provided within the container, and a diaphragm provided between the anode and the cathode. In this electrolyzer, the partition wall prevents the electrolysis products generated at each electrode from mixing. In this type of electrolyzer, the anode and cathode are usually made of nickel-plated steel plates, and the diaphragm is made of asbestos or the like.

Electrolysis of alkaline aqueous solutions (20% caustic soda solution, 25% caustic potassium solution, etc.) in such an electrolyzer requires a voltage of approximately 1.9 V to 2.2 V and a current of approximately 5 to 10 A/min between the electrodes.
This is done by applying ^dm2 .

"Problems to be Solved by the Invention" Such conventional electrolyzers have had the following problems.

(1) Bubbles from electrolysis products generated at the anode and cathode remain in the electrolyte, resulting in a large overvoltage. For this reason, high voltage is required to perform electrolytic decomposition.

(2) Furthermore, due to the diaphragm provided to prevent mixing of electrolyzed products, the distance between the anode and cathode is large, resulting in low current efficiency.

(3) Furthermore, in electrolyzers that use such diaphragms to prevent mixing of electrolyzed products, if electrolysis is performed under high pressure to produce the products hydrogen gas and oxygen gas at high pressure, the anode It is difficult to control the pressure difference caused by the difference between the amount of gas generated and the amount of gas generated from the cathode, and there is a problem in that the gases generated at the anode and cathode mix through the diaphragm. Therefore, in order to obtain high-pressure gas in an electrolyzer equipped with a conventional diaphragm, the produced gas had to be compressed again.

(4) In addition, problems such as asbestos being carcinogenic have been pointed out, and there have been complaints that the installation of electrolyzers equipped with such asbestos diaphragms comes with various restrictions.

The present invention has been made in view of the above circumstances, and enables efficient electrolysis of a solution and purification and separation of gas from the solution. The purpose of the present invention is to provide a gas separation module that can prevent the occurrence of overvoltage associated with the current density, improve current density, and reduce the amount of expensive catalyst used.

"Means for Solving the Problems" The gas separation module of the present invention includes an anode and a cathode electrode for electrolyzing a solution, a solution chamber into which a solution is supplied and discharged, and a partition wall in this solution chamber. at least a part of the partition wall is formed by bonding a large number of electrically conductive fine particles, and has a diameter of 0.5 μm.
A porous gas permeable layer with a porosity of 40 to 80% and a large number of pores of less than
A gas permeable material having a large number of pores of 0.5 μm or less and a porosity of 40 to 80%, and comprising a reaction layer carrying a catalyst therein to promote the electrolysis reaction of the solution. at least one of the cathode and the anode of the electrode in the solution chamber is formed by the gas permeable membrane, the reaction layer is directed toward the solution chamber, and the reaction layer is thinner than the gas permeation layer. It is something that is formed.

"Example" Hereinafter, the gas separation module of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a first embodiment of the gas separation module of the present invention, and reference numeral 1 in the figure represents a solution chamber. The solution chamber 1 is a part where an electrolytic solution is stored, and is formed by a narrow space. The width of this solution chamber 1 is normally formed to be about 1.5 to 0.8 mm.
It is not limited to this value, and can be made even narrower if it does not affect the assembly accuracy of the device or the storage of the electrolyte. In the gas separation module of this example, openings 1a and 1b communicating with the outside are provided at both ends of the solution chamber 1, respectively, and the electrolyte is formed to flow through the solution chamber 1.
Side walls 1c, 1 of this solution chamber 1 facing each other at a narrow interval
d, an electrode 2 is attached to one side wall 1c. This electrode 2 is made of metal, and a nickel-plated steel plate is preferably used.
Furthermore, an air chamber 4 is provided on the other side wall 1d at a position facing the electrode 2 with a partition wall 3 interposed therebetween. This air chamber 4 is a chamber for recovering separated and generated gas, and has a flow path 4a leading to the outside on the side facing the partition wall 3.
is formed.

In the gas separation module of this example, the partition wall 3 is entirely formed of the gas permeable membrane 5.

This gas permeable membrane 5 has electrical conductivity and gas permeability, and as shown in FIG.
and a reaction layer 5b. This gas permeable membrane 5 is attached to the gas separation module so that the reaction layer 5b faces the solution chamber 1.

The gas permeable layer 5a of the gas permeable membrane 5 is a porous layer formed by bonding conductive fine particles (hereinafter abbreviated as conductive fine particles). The pores formed in the gas permeable layer 5a are preferably continuous pores with a diameter of 0.5 μm or less, preferably 800 Å or less. If the pore diameter exceeds 0.5 μm, the gas permeable layer 5a
is capable of permeating not only molecules in a gaseous state but also molecules in a liquid state, resulting in a disadvantage that the gas-liquid separation function is deteriorated.

Further, the porosity of the gas permeable layer 5a is preferably about 40% to 80%. If the porosity of the gas permeable layer 5a exceeds 80%, the water pressure resistance strength of the resulting gas permeable membrane 5 will be insufficient, and if the porosity is less than 40%, the gas permeation rate of the gas permeable layer 5a will decrease. Either case is unfavorable because the decomposition product gas cannot be efficiently released.

Materials for the conductive fine particles forming the gas permeable layer 5a include metals such as iron, nickel, silver, and copper, amorphous carbon, carbon such as graphite, conductive titanium oxide, and boron compounds [lanthanum boride (LaB ₆ )]. Various materials can be used, such as conductive ceramics such as titanium boride (TiB ₂ )]. Among them, carbon is preferably used because it has excellent water repellency and corrosion resistance, and the resulting gas permeable membrane 5 has a long life and good chemical resistance.

The conductive fine particles used here have a particle size of
A thickness of 0.1 μm or less is preferable. If the particle size exceeds 0.1 μm, a problem arises in that large pores are formed in the gas permeable layer 5a.

These conductive fine particles forming the gas permeable layer 5a are
They are bonded via a binder or by sintering or the like. In the gas permeable layer 5a of the gas permeable membrane 5 of this embodiment, conductive fine particles are bound by an organic polymer compound as a binder.

The organic polymer compound that binds the conductive fine particles of the gas permeable layer 5a includes fluororesin, silicone resin,
Various synthetic resin materials can be used, such as polyethylene, polypropylene, polyacrylonitrile, polyvinyl chloride, polycarbonate, and polyethylene terephthalate. Among them, fluororesins such as polytetrafluoroethylene (PTFE), polychlorotrifluoroethylene, polyvinyldene fluoride, tetrafluoroethylene-hexafluoropropylene copolymer (FEP), and especially PTFE
is preferably used because it has excellent corrosion resistance that is not attacked by acids or alkalis, and has excellent water repellency, and the resulting gas permeable membrane 5 has a long life and chemical resistance. Also, PTFE
A mixture of two or more synthetic resin materials such as FEP and the like is also suitably used.

When the conductive fine particles are bonded using an organic polymer compound in this way, the amount of the organic polymer compound to be added is as follows, for example, when PTFE is used as the organic polymer compound and carbon black is used as the conductive fine particles. Usually 10% of PTFE by weight relative to their total amount
It is said to be around 60%. When the amount of organic polymer compound added exceeds 60%, a gas permeable layer 5a is formed.
The electrical resistance of the gas permeable layer 5a increases, and the gas permeability of the gas permeable layer 5a deteriorates. Furthermore, if the amount added is less than 10%, the binding of the conductive fine particles becomes insufficient and the strength of the gas permeable layer 5a decreases.

This gas permeable layer 5a is desirably formed to have a thickness of approximately 2 mm or less. If the thickness of the gas permeable layer 5a exceeds 2 mm, a disadvantage arises in that the gas permeation rate of the gas permeable layer 5a decreases. Furthermore, if the thickness of the gas permeable layer 5a is less than 0.3 mm, the strength of the gas permeable layer 5a may be reduced. However, depending on manufacturing conditions, it is possible to obtain a gas permeable layer 5a having sufficient strength even with a thickness of 0.1 mm or less.

The reaction layer 5b formed on the surface of the gas permeable layer 5a supports a catalyst.

Catalysts used in the reaction layer 5b include iron group elements such as nickel (Ni), cobalt (Co), and iron (Fe), which promote chemical reactions such as electrolysis, or platinum (Pt), ruthenium (Ru), and gold. (Au), silver (Ag),
Various catalysts can be used, such as catalysts made of noble metal elements such as copper (Cu), chromium (Cr), manganese (Mn), and palladium (Pd), their oxides, or their alloys. Among them, catalysts made of Ni, Pt, Ru, etc. are used for electrolysis of aqueous solutions, etc.
It is preferably used because it can significantly improve electrolytic efficiency.

In the reaction layer 5b, these catalysts are supported and fixed on a carrier. Various carriers can be used. A porous carrier is preferably used as the carrier forming the reaction layer 5b since it can support a larger amount of catalyst. In that case, the diameter of the hole is approximately 0.5 μm to 0.01 μm, and the reaction layer 5
The porosity of b is approximately 40% to 80%.

When the diameter of the reaction layer 5b exceeds 0.5 μm, the strength of the reaction layer 5b decreases. In addition, when the diameter is less than 0.01 μm, it becomes difficult for the solution to penetrate into the reaction layer 5b.
Only the surface of the reaction layer 5b contributes to reactions such as electrolysis, resulting in a disadvantage that the reaction efficiency is reduced.

Furthermore, if the porosity of the carrier constituting the reaction layer 5b exceeds 80%, the resulting reaction layer 5b will have insufficient durability, which is not preferable. If the porosity is less than 40%, a sufficient amount of catalyst cannot be supported, which is not preferable.

As the carrier forming the reaction layer 5b, various types of ceramics such as alumina (Al ₂ O ₃ ) and silica (SiO ₂ ), conductive fine particles, etc. bound together by a binder or sintering treatment can be used. Among these, those formed by bonding conductive fine particles are preferable because they can reduce the electrical resistance of the reaction layer 5b.

The conductive fine particles of the reaction layer 5b include silver, copper,
The same conductive particles as those forming the gas permeable layer 5a can be used, such as metals such as nickel and gold, and carbons such as amorphous carbon and graphite.

As the conductive fine particles, those having a particle size of 0.5 μm or less are preferably used. If the particle size exceeds 0.5 μm, a problem arises in that large pores are formed in the gas permeable layer 5a.

Similarly to the gas permeable layer 5a, the reaction layer 5b of the membrane of this example has conductive fine particles bound by an organic polymer compound as a binder. As this organic polymer compound, the same organic polymer compound as used for the gas permeable layer 5a can be used.

Further, it is desirable that the reaction layer 5b has a structure in which hydrophilic portions and water-repellent portions are finely distributed in a network so as to be able to appropriately contact the aqueous solution. The reaction layer 5b having such a structure is formed by making the carrier a mixture of hydrophilic fine particles and water-repellent fine particles. Examples of such fine particles include general acetylene black as a water-repellent particle, and VulcanXC- as a hydrophilic particle.
72R (hydrophilic carbon, product name: manufactured by Kyabot Co., Ltd.)
Examples include.

This reaction layer 5b is desirably formed to have a thickness of about 1.0 mm or less. The thickness of this reaction layer 5b is
If it exceeds 1.0 mm, there will be an inconvenience that the gas generated in the reaction layer 5b will be difficult to permeate into the gas permeable layer 5a.

Next, an example of a method for manufacturing the gas permeable membrane 5 used in the gas separation module of the present invention will be described.

The explanation is based on organic polymer compounds as binders.
We will use a gas permeable membrane made of PTFE and carbon black as conductive particles as an example.

To manufacture this gas permeable membrane, first, 70 parts by weight of carbon black having an average particle size of 0.042 μm and 30 parts by weight of PTFE having an average particle size of 0.25 μm are thoroughly mixed to prepare a mixture A. It also has hydrophilic properties.
VulcanXC−72R, 70 parts by weight and average particle size 0.25μm
Mixture B is prepared by sufficiently mixing with PTFE. Next, these mixtures A and B are mixed at a ratio of A:B=4:6, an organic solvent (naphtha) is added, and the mixture is uniformly kneaded. Press this to create a sheet A with a thickness of 0.4 mm.
to form.

Separately, a mixture C was prepared by sufficiently mixing 70 parts by weight of carbon black with an average particle size of 0.042 μm and 30 parts by weight of PTFE with an average particle size of 0.25 μm, and an organic solvent (naphtha) was added to this mixture to form a paste. Knead thoroughly until it becomes . Pressurize this thing,
Form sheet B with a thickness of 2.5 mm.

The two types of sheets A and B formed in this way are overlapped and pressed together with a roller to be joined together to form a sheet with a thickness of 0.9 mm. This product is dried to evaporate the solvent used, and then heat treated in a heating oven at 280°C. Next, this material is hot pressed at 380° C. for a predetermined period of time to form a sheet with a thickness of 0.8 mm. Next, a catalyst is supported on the portion formed by the sheet A.

A simple method for supporting the catalyst is to apply or spray a solution in which the catalyst is dissolved (catalyst solution) onto the surface of the sheet and allow it to penetrate into the sheet, and then dry it. In this way, the touch can be carried even inside the reaction layer 5b.

Note that a metal mesh is attached to this gas permeable membrane 5 if necessary. When pasting a metal net, its position may be on the surface on the gas permeable layer 5a side, on the surface on the reaction layer 5b side, or between the gas permeable layer 5a and the reaction layer 5b. As the metal mesh, one made of a metal with good electrical conductivity such as copper, pickle, gold-plated copper, DSA type titanium, etc. is suitably used. In addition, it is desirable that the mesh size of the metal net is about 30 to 100, and the metal fibers that make up the metal net have a diameter of about 30 to 100.
A material having a diameter of about 100 μm to 500 μm is preferably used.

Further, when a metal mesh is provided between the gas permeable layer 5a and the reaction layer 5b or on the surface of the reaction layer 5b, the gas permeable layer 5a does not need to be electrically conductive.
Therefore, non-conductive materials such as carbon fluoride and hydrophobic silica can be used as the carrier.

Such adhesion of the metal net is carried out, for example, by setting the metal net at an appropriate position when superimposing the sheets A and B, and hot-pressing the same.

The gas separation module of the present invention equipped with such a gas permeable membrane 5 is incorporated into an electrolyzer as shown in FIG. 3 and put into practical use. In the electrolysis device shown in FIG. 3, openings 1a and 1b of a solution chamber 1 of a gas separation module are connected to an electrolyte tank 6 to form a closed electrolyte flow path 7. An electrolyte flow path 7 between the opening 1a of the gas separation module and the electrolyte tank 6 is provided with a filter 8 for removing foreign matter from the electrolyte and a pump 9 for circulating the electrolyte.
is provided. On the other hand, an electrolyte flow path 7 between the opening 1b of the gas separation module and the electrolyte tank 6
is equipped with a gas-liquid separator 10 that separates gas generated at the electrode 2 of the solution chamber 1 of the gas separation module, and a cooler 11 that maintains the electrolyte at a predetermined temperature.

In addition, the flow path 4a of the air chamber 4 of the gas separation module
A cooler 12 for cooling the obtained gas is connected thereto.

“Function” Next, the function of the gas separation module of the present invention is as follows.
The operation of the electrolyzer shown in FIG. 3 will be explained.

In FIG. 3, when electrolyzing water using an electrolysis device, first, the pump 9 is driven to circulate the electrolytic solution into the solution chamber 1 of the gas separation module. In this state, electricity is applied to the electrode 2 provided in the solution chamber 1 and the gas permeable membrane 5 forming the partition wall 3 to perform electrolysis. Then,
Electrode 2 and gas permeable membrane 5 of gas separation module
Oxygen gas and hydrogen gas are generated in the reaction layer 5b depending on the polarity. At this time, the gas generated in the reaction layer 5b of the gas permeable membrane 5 is released into the air chamber 4 through a hole having a diameter of 800 Å or less formed in the gas permeable layer 5a. The pressure of the gas released into the air chamber 4 is
This is approximately equal to the pressure of the electrolytic solution in the solution chamber 1. On the other hand,
The gas generated at the electrode 2 is transferred to the solution chamber 1 together with the electrolytic solution.
The liquid flows out from the opening 1b, and is separated from the electrolytic solution and taken out by the gas-liquid separator 10 provided at the next stage.

Embodiment 2 FIG. 4 shows a second embodiment of the gas separation module of the present invention, in which the same components as those of the first embodiment are given the same reference numerals to simplify the explanation.

In the gas separation module of this example, a mesh-shaped electrode 2 is provided in the solution chamber 1, and a third opening 1e is formed at a position facing the mesh-shaped electrode 2.

In the gas separation module of this example, an electrolytic solution is supplied to the solution chamber 1 from the openings 1a and 1b,
It passes through the electrode 2 and is discharged from the opening 1e. The electrolytic products generated at the mesh-shaped electrode 2 pass through the electrode 2 and pass through the opening 1 along with the electrolytic solution.
It is discharged from e. As a result, in this gas separation module, the efficiency of discharging the electrolysis products generated at the electrode 2 is improved.

Embodiment 3 FIG. 5 shows a third embodiment of the gas separation module of the present invention, and the same components as those of the first embodiment are given the same reference numerals to simplify the explanation.

In the gas separation module of this example, two air chambers 4, 4 are provided in the solution chamber 1 so as to face each other, and are separated by partition walls 3, 3 formed by gas permeable membranes 5, 5, respectively. , separated from the solution chamber 1.

In the gas separation module of this example, the gas permeable membranes 5, 5 are provided at two locations, so that electrolysis can be carried out by using these as a cathode and an anode, respectively. Then, the gas generated in each gas permeable membrane 5, 5 by electrolytic decomposition passes through the hole having a diameter of 800 Å or less in the gas permeable layer 5a, 5a, respectively, and is released into the air chambers 4, 4. In the gas separation module of this example, the gas produced at the cathode and the anode are both discharged from the solution chamber 1 to the air chambers 4, 4, so the gas-liquid separator 10 is There is no need to connect them.

Experimental Example 1 The gas separation module shown in FIG. 5 was prototyped, and water was electrolyzed to produce hydrogen gas and oxygen gas. The distance between gas permeable membranes A and B was set to 1 mm.

The specifications of the gas permeable membranes A and B used in this experiment are as follows.

() Gas permeable membrane A Structure: Three-layer structure in which a reaction layer 5b with a thickness of 0.1 mm, a gas permeable layer 5a with a thickness of 0.5 mm, and a copper mesh are sequentially laminated.

Area: 900cm ² (a) Reaction layer 5b Composition: 65 parts by weight of carbon, average particle size 0.042μ
m PTFE35 parts by weight, average particle size 0.25μm Catalyst: RuO ₂ , particle size 100Å (b) Gas permeable layer 5a Composition: 70 parts by weight carbon, average particle size 0.042μm
m 30 parts by weight of PTFE, average particle size 0.25 μm Porosity: 65% Pore diameter: Average 460 Å () Gas permeable membrane B Structure: 0.1 mm thick reaction layer 5b, 0.5 mm thick gas permeable layer 5a, made of copper A three-layer structure in which the nets and nets are laminated in sequence.

Area: 900cm ² (a) Reaction layer 5b Composition: 70 parts by weight of carbon, average particle size 0.038μ
m 30 parts by weight of PTFE, average particle size 0.25 μm Catalyst: Platinum-based, particle size 50 Å (b) Gas permeable layer 5a Composition: 70 parts by weight carbon, average particle size 0.042 μm
m PTFE 30 parts by weight, average particle size 0.25 μm Porosity: 65% Pore diameter: average 450 Å A 20 mol% dilute sulfuric acid solution was placed in the solution chamber 1 of the gas separation module equipped with such gas permeable membranes A and B. A voltage of 1.8 V and a current of 900 A were applied between gas permeable membranes A and B while supplying the gas at a rate of 0.12/min. At this time, gas permeable membrane A was used as an anode, and gas permeable membrane B was used as an anode.

When the device was operated under the above conditions, air chamber 4,
4, oxygen gas was obtained at 3.13/min (under standard conditions) and hydrogen gas at 6.25/min (under standard conditions), respectively.

Next, we conducted a similar experiment using an alkaline solution (25wt% potassium hydroxide solution), a neutral solution (20wt% sodium sulfate solution), etc. instead of the sulfuric acid solution, and found that oxygen gas and hydrogen gas were also was able to produce it. The purity of these oxygen gas and hydrogen gas was 99.999%.

During this experiment, when the pressure in the solution chamber 1 of the gas separation module was increased to 2.2 Kg/cm ² G, the pressure of the gas recovered from the gas chambers 4 and 4 was both 2.0
Kg/ ^cm2・G. Then, when the pressure in the solution chamber 1 was further increased to 7.2Kg/cm ²・G, the pressure of the obtained gases became 7.0Kg/cm ²・G, and the gas separation module of the present invention lowered the pressure in the solution chamber 1 It has been found that the gas obtained from the air chambers 4, 4 can be pressurized by increasing the pressure. When the pressure in the solution chamber 1 was gradually increased, no permeation of the solution through the gas permeable membranes 5, 5 was observed up to a pressure of 20 kg/cm ² G. It was confirmed that it was possible to maintain the Reduce the pressure of solution chamber 1 to 20Kg/
When cm ²・G, the pressure of the obtained gas is 19.0
It was Kg/cm ²・G.

When the gas separation module was operated with one of the permeable membranes A and B replaced with a mesh-like platinum-plated titanium electrode, oxygen gas and hydrogen gas could be obtained in the same manner. When the module was operated in this manner, the life of the membrane 5 could be extended.

Experimental Example 2 Using the gas separation module prototyped in Experimental Example 1, carbon dioxide gas and hydrogen gas were produced.

The specifications of the gas permeable membranes A and B used in this experiment are as follows.

() Gas permeable membrane A Structure: Three-layer structure in which a reaction layer 5b with a thickness of 0.1 mm, a gas permeable layer 5a with a thickness of 0.5 mm, and a copper net are laminated in sequence.

Area: 900cm ² (a) Reaction layer 5b Composition: 70 parts by weight of carbon, average particle size 0.042μ
m PTFE 30 parts by weight, average particle size 0.25 μm Catalyst: Platinum catalyst with particle size 50 Å and particle size
100Å RuO ₂ catalyst (b) Gas permeation layer 5a Composition: 70 parts by weight of carbon, average particle size 0.042μ
m 30 parts by weight of PTFE, average particle size 0.25 μm Porosity: 65% Pore diameter: Average 450 Å () Gas permeable membrane B Structure: 0.1 mm thick reaction layer 5b, 0.5 mm thick gas permeable layer 5a, made of copper A three-layer structure in which the nets and nets are laminated in sequence.

Area: 900cm ² (a) Reaction layer 5b Composition: 70 parts by weight of carbon, average particle size 0.038μ
m 30 parts by weight of PTFE, average particle size 0.25 μm Catalyst: Platinum-based, particle size 50 Å (b) Gas permeable layer 5a Composition: 70 parts by weight carbon, average particle size 0.042 μm
m PTFE 30 parts by weight, average particle size 0.25 μm Porosity: 65% Pore diameter: average 450 Å In the experiment, first, a raw material solution was prepared by mixing 10 vol% methanol with a 0.5 mol/diluted sulfuric acid solution. Then, while supplying this raw material solution to the gas separation module solution chamber 1 for 0.1 minute at 2.0 kg/cm ² G, a voltage of 0.6 to 0.7 V and a current of 0.6 to 0.7 V were applied between the gas permeable membranes A and B.
450A was applied. At this time, gas permeable membrane A is used as an anode,
Gas permeable membrane B was used as a cathode. Further, the temperature of the raw material solution was 65°C.

When the device was operated under the above conditions, the air chamber 4 on the gas permeable membrane A side, which is the anode, showed a purity of 99.9% and pressure.
Carbon dioxide gas of 1.5Kg/cm ² G is converted to standard conditions and is obtained at 1.03 per minute, and hydrogen with a purity of 99.9% and a pressure of 1.5Kg/cm ² G is produced from the air chamber 4 on the gas permeable membrane B side, which is the cathode. By converting the gas to standard conditions, we were able to obtain 6.24 per minute.

In this device, methanol has a depolarizing effect, making it possible to significantly reduce power consumption.

Experimental Example 3 The separation module shown in Figure 4 was prototyped and water electrolysis was performed.

As the electrode 2 of the gas separation module, a platinum-plated titanium mesh electrode was used.

Furthermore, the gas permeable membrane 5 used had the following specifications.

Structure: Three-layer structure in which a reaction layer 5b with a thickness of 0.1 mm, a gas permeation layer 5a with a thickness of 0.5 mm, and a copper net are laminated in sequence.

Area: 900 cm ² (a) Reaction layer 5b Composition: 70 parts by weight of carbon, average particle size 0.038 μm 30 parts by weight PTFE, average particle size 0.25 μm 5 parts by weight FEP, average particle size 0.2 μm Catalyst: Nickel-based, average particle size 300 Å ( b) Gas permeation layer 5a Composition: 50 parts by weight of carbon, average particle size 0.042 μm 20 parts by weight of carbon fluoride, average particle size 0.01 μm 30 parts by weight PTFE, average particle size 0.25 μm Porosity: 64% Pore diameter: Average 440 Å The distance between these electrodes 2 and the gas permeable membrane 5 was 1 mm.

With such a gas separation module, the electrode 2
is the anode, the gas separation membrane 5 is the cathode, and the current density is
When a 5% sulfuric acid solution was electrolyzed at 50 A/dm ² and a bath voltage of 2.3 V, hydrogen gas with a purity of 99.999% could be obtained from the air chamber 4.

When the gas separation module was operated continuously for 30 days under this condition, the bath voltage remained constant at 2.3V.
As a result, it was found that this gas separation module was sufficiently durable for practical use.

In addition, in the gas separation module using this mesh-shaped electrode 2, the gas generated at the electrode 2 was quickly discharged from the opening 1e along with the flow of the sulfuric acid solution.

Furthermore, in this experiment, since a sulfuric acid solution was used as the electrolytic solution, gas-liquid separation could be performed satisfactorily.

In this experiment, when the current density was successively varied up to 200 A, the bath voltage increased in proportion to the current density, as shown in FIG.

In addition, when electrolysis was carried out with electrode 2 as the cathode and gas permeable membrane 5 as the anode, and the current density was varied, as shown in Fig. 7, the bath voltage decreased as the current density increased, as shown in Figure 7. .

Note that the gas separation module of the present invention is not limited to the above embodiments. For example, according to the gas separation module of the present invention, various gases such as not only oxygen gas and hydrogen gas but also chlorine gas can be produced and purified as long as they can be ionized.

Furthermore, when the gas separation module of the present invention is put to practical use, it goes without saying that a plurality of modules may be used in series.

Furthermore, the gas separation module of the present invention has a wide range of applications, and can be used not only for water electrolysis and gas separation and purification, but also for fuel cells and the like.

"Effects of the Invention" As explained above, the gas separation module of the present invention combines conductive fine particles to
Has a large number of pores of 0.05 μm or less, and has a porosity of 40 to 80%.
It is made by combining a porous gas permeable layer with conductive fine particles integrated on the surface side of this gas permeable layer, and has a large number of pores with a diameter of 0.5 μm or less, and has an air efficiency of 40
The electrode is formed by a gas permeable membrane, which is a porous material with a thickness of ~80 mm and has a reaction layer supporting a catalyst that promotes the electrolysis reaction of the solution. Purification and separation can be carried out efficiently.

Further, the gas module of the present invention combines conductive fine particles and has a large number of pores with a diameter of 0.5 μm or less,
It is a porous body with a porosity of 40 to 80%, and is equipped with a gas permeable membrane having a reaction layer with a thickness of 1.0 mm or less that supports a catalyst that promotes the electrolysis reaction of the solution. Since the catalyst can be widely supported on the reaction layer, the amount of expensive catalyst such as platinum used can be reduced, and the manufacturing cost of the electrolyzer can be reduced. Furthermore, since the reaction layer is formed thinner than the gas permeation layer, the amount of catalyst used can be reduced, and this thin porous reaction layer promotes electrolysis, and the bubbles of reaction products generated by the accelerated electrolysis are removed. can be reliably guided to the gas permeation layer.

When the gas separation module of the present invention is used in an electrolytic device, the gas generated in the reaction layer of the gas permeable membrane as an electrode is quickly released to the outside of the system through the gas permeable layer of the gas permeable membrane. Ru. As a result, the surface of the gas permeable membrane serving as an electrode is not covered with bubbles or the generated gas remains in the solution chamber, and depolarization and overvoltage caused by the generated gas can be reduced. Therefore, according to the gas separation module of the present invention, electrolysis can be performed with a lower voltage and with good current efficiency (a current efficiency of 99.5% or more can be achieved). In addition, the current density can be significantly improved to 100 to 500 A/dm ² (conventionally, the maximum for water electrolysis devices is about 10 to 20 A/dm ² ).

Furthermore, in the gas separation module of the present invention, the generated gas can be immediately released from the system through the gas permeable membrane, so there is no need to provide a diaphragm at the anode and cathode. Therefore, in the gas separation module of the present invention, the distance between the anode and the cathode can be made sufficiently small;
This also makes it possible to improve the current efficiency of the device and reduce the voltage between electrodes. Furthermore, since there is no need to provide a diaphragm, the solution chamber can be reduced and the size of the electrolytic device can be reduced.

Furthermore, in the gas separation module of the present invention, the generated gas is immediately released from the gas permeable membrane to the outside of the system, so there is no need to manage the differential pressure of each generated gas obtained at the anode and cathode. It is possible to obtain gas at a pressure approximately equal to the pressure in the solution chamber. Therefore, the gas separation module of the present invention can increase the pressure in the solution chamber to produce and purify high-pressure gas, and can also be used as a gas pressurization device. Further, since the gas permeable membrane constituting the gas separation module of the present invention has high pressure resistance, gas at considerably high pressure can be easily produced.

Furthermore, since the gas permeable membrane constituting the gas separation module of the present invention has a gas-liquid separation function, the gas is purified by the gas permeable membrane according to the gas separation module of the present invention, and has a high purity (99.999% or more).
You can get gas.

Further, since the gas separation module of the present invention does not require a diaphragm, there is no need to use carcinogenic asbestos, and the electrolytic device can be installed as desired.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing one embodiment of the gas separation module of the present invention, FIG. 2 is a cross-sectional view showing an example of the gas permeable membrane used in the gas separation module of the present invention, and FIG. 3 is a first embodiment. 4 and 5 are cross-sectional views showing second and third embodiments of the gas separation module of the present invention, and FIG. 6 and FIG. FIG. 7 is a graph showing the relationship between current density and bath voltage investigated in Experimental Example 3. 1... Solution chamber, 2... Electrode, 3... Partition wall, 4...
...Air chamber, 5...Gas permeable membrane, 5a...Gas permeable layer, 5b...Reaction layer.

Claims (1)

[Scope of Claims] 1. A solution chamber provided with anode and cathode electrodes for electrolyzing a solution, into which a solution is supplied and discharged, and one or more gas chambers connected to this solution chamber via a partition wall. at least a part of the partition wall is formed by bonding a large number of conductive fine particles, has a large number of pores with a diameter of 0.5 μm or less, and has a porosity of 40 to 80%.
A porous gas-permeable layer with a thickness of 2.0 mm or less, and conductive fine particles integrated on the surface side of this gas-permeable layer, with a porosity of 40% having a large number of pores with a diameter of 0.5 μm or less. ~80% porous material,
It is formed of a gas permeable membrane comprising a reaction layer with a thickness of 1.0 mm or less that supports a catalyst for promoting the electrolysis reaction of the solution, and at least one of the cathode and the anode of the electrode of the solution chamber is formed. A gas separation module comprising the gas permeable membrane, wherein the reaction layer faces the solution chamber side, and the reaction layer is formed thinner than the gas permeation layer.