JP2016028812A - Hydrogen separator and hydrogen separation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydrogen separation method capable of efficiently separating hydrogen using a molecular sieve membrane and preventing the occurrence of explosion due to a hydrogen oxygen reaction without using diluted gas.SOLUTION: A gas mixture containing hydrogen and oxygen is supplied underwater into one space out of one space and the other space across a molecular sieve membrane separated by the molecular sieve membrane, and hydrogen in the gas mixture is selectively permeated from one space to the other space across the molecular sieve membrane so as to directly separate hydrogen from the gas mixture.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a hydrogen separator using a molecular sieve membrane and a hydrogen separation method. In particular, the present invention relates to a technique for separating hydrogen from a mixed gas containing hydrogen and oxygen produced by a water splitting reaction using sunlight.

  In recent years, attention has been focused on a technique for producing hydrogen and oxygen by decomposing water using a photocatalyst and solar energy. Here, in the photohydrolysis reaction using a photocatalyst, hydrogen and oxygen may be generated simultaneously in the system. In this case, it is necessary to separate the generated hydrogen and oxygen. For example, in a hydrogen production process by water splitting of a photocatalyst, techniques for separating hydrogen and oxygen using a separation membrane such as a molecular sieve membrane have been proposed (Non-Patent Documents 1 and 2).

Tanaka et al., “Application of Hydrogen Separation Membrane to Photocatalytic Hydrogen Production Process”, Membrane Symposium No. 21 (2009) Sugiyama et al., "Efficient separation of H2 and O2 produced by photocatalytic water complete decomposition using a gas separation membrane", 104th Catalytic Conference, Proceedings of Conference A, p. 20, (2009)

  As disclosed in Non-Patent Documents 1 and 2, when a photocatalytic reactor and a separation membrane module are combined, there is a problem that an explosion easily occurs due to a reaction between hydrogen and oxygen in the separation membrane module. This problem can be addressed, for example, by controlling the hydrogen concentration and oxygen concentration in the separation membrane module to a composition outside the explosion range using an inert diluent gas. However, when a dilution gas is used, the separation membrane module becomes large, and in order to obtain high-concentration hydrogen and oxygen, a separation process between the dilution gas and hydrogen and / or oxygen is further required. It becomes complicated. Moreover, since the hydrogen concentration and the oxygen concentration are lowered by the dilution gas, when it is desired to separate and recover a large amount of hydrogen and oxygen, the separation efficiency is deteriorated.

  Therefore, the present invention has an object to provide a hydrogen separation apparatus and a hydrogen separation method that can efficiently separate hydrogen using a molecular sieve membrane and can prevent an explosion due to a reaction between hydrogen and oxygen. To do.

  The present inventors directly separated the mixed gas containing hydrogen and oxygen generated in the water by the water splitting reaction of the photocatalyst in the water, so that the explosion caused by the reaction of hydrogen and oxygen without using a dilution gas. Inspired to prevent. As a result of diligent research, hydrogen was selected from one space of the molecular sieve membrane to the other using the molecular sieve membrane as a driving force after partitioning the space by immersing the molecular sieve membrane in water. It was found that hydrogen and oxygen in water can be directly separated by permeation.

The present invention has been completed based on the above findings. That is,
A first aspect of the present invention is a hydrogen separation apparatus for separating hydrogen from a mixed gas containing hydrogen and oxygen generated by water splitting of a photocatalyst, comprising a porous substrate and a molecular sieve formed on at least one side of the porous substrate. A hydrogen separator having a membrane, connected to the hydrogen separator, a recovery port for recovering hydrogen separated from the mixed gas through the hydrogen separator, and a gas other than hydrogen is discharged. And a storage body that stores the hydrogen separator, and the storage body is filled with water or a water-containing liquid (hereinafter referred to as “water etc.”). The hydrogen separator is housed in a position where one side of the hydrogen separator contacts the water or the like, and the hydrogen separator separates the hydrogen from the mixed gas existing in the water or the like. With hydrogen separator That.

  In the present invention, the “photocatalyst” refers to a catalyst that decomposes water into hydrogen and oxygen using sunlight, and may be either a particle or a molded body, and the molded body may contain a binder. A mixture thereof may also be used.

  The “mixed gas containing hydrogen and oxygen” refers to a gas containing at least hydrogen and oxygen that can be generated by water splitting of the photocatalyst. In addition to hydrogen and oxygen, other gas such as water vapor may be included. Good.

  “Porous substrate” refers to a support having an outer side surface (outer wall) and an inner side surface (inner wall) and formed of a porous material. That is, it is a support that can partition the outer space and the inner space with a porous material. The shape of the support is not particularly limited, and examples thereof include a tubular support, a cylindrical support, a flat support, a honeycomb support having a large number of prismatic holes, and a porous support such as a monolith.

  “Molecular sieve membrane” refers to a membrane that selectively allows molecules to permeate through molecular sieving ability. In the present invention, it refers to a membrane having a higher hydrogen permeability than oxygen.

  “Molecular sieve membrane formed on at least one side of the porous substrate” means that the molecular sieve membrane is provided on the outer wall surface, the inner wall surface, or both of the porous substrate.

  The “recovery port for recovering hydrogen separated from the mixed gas” refers to an opening provided in the storage body for recovering hydrogen separated by the hydrogen separator. In the present invention, a small amount of gas (oxygen, water vapor, etc.) other than hydrogen that has permeated the hydrogen separator can also be recovered from the recovery port.

  The “exhaust port for discharging gas other than hydrogen” refers to an exhaust port for discharging gas such as oxygen that has not been separated by the hydrogen separator. In the present invention, when it is difficult to separate and recover 100% of hydrogen from the mixed gas, hydrogen that has not been separated by the hydrogen separator can also be discharged from the discharge port. In that case, when exhaust gas having a high oxygen concentration containing hydrogen enters the explosion range, the explosion can be avoided by a method of avoiding by diluting with an inert gas such as nitrogen.

  “The storage body is filled with water or a water-containing liquid (hereinafter referred to as“ water ”)” means that water or the like circulates in the storage body in addition to a static flow of water or the like in the storage body. This is a concept including a form in which the flow of water or the like is dynamic.

  "Water-containing liquid" is a concept that includes both those in which soluble components other than water are dissolved or those in which some insoluble components exist in addition to water. For example, aqueous solutions in which soluble components such as electrolytes are dissolved And water in which insoluble components other than the photocatalyst are present.

  “When one side of the hydrogen separator is in contact with water when it is filled with water”, in other words, the hydrogen separator is stored in the storage body, and the water etc. is stored in the storage body. Means that the water or the like filled in the inner wall or outer wall of the stored hydrogen separator comes into contact. That is, the hydrogen separator is configured to come into contact with water or the like when the hydrogen separator is in operation even when it is in a state before being operated as a hydrogen separator (a state in which the storage body is not filled with water or the like). Anything is included in the first aspect of the present invention.

  “Contact” means not only a form in which one side of the hydrogen separator is brought into contact with a liquid surface such as filled water, but also a form in which the hydrogen separator is immersed in a liquid such as filled water (water is contained in the hydrogen separator). And the like).

  A second aspect of the present invention is an apparatus for separating hydrogen from a mixed gas containing hydrogen and oxygen that can be generated by water splitting of a photocatalyst, comprising a porous substrate and a molecular sieve membrane formed outside or inside the porous substrate. A hydrogen separator, and a storage port for recovering hydrogen separated from the mixed gas and a discharge port for discharging a gas other than hydrogen, and storing the hydrogen separator The container is filled with water or a water-containing liquid (hereinafter referred to as “water etc.”), the mixed gas is present in the water etc., and at least one of the hydrogen separators. The hydrogen separator is characterized in that a part is impregnated in the water or the like, and hydrogen can be separated from the water or the like to the recovery port via the hydrogen separator.

  “Molecular sieve membrane formed outside or inside the porous substrate” means that the molecular sieve membrane is provided on the outer wall surface, the inner wall surface, or both of the porous substrate.

  “At least a part of the hydrogen separator is impregnated in water or the like” means that at least a part of the hydrogen separator is immersed in a liquid such as water.

  In the first or second aspect of the present invention, the storage body may further include an introduction port in addition to the recovery port and the discharge port. The storage body is preferably made of a material that easily transmits sunlight.

  In the first or second aspect of the present invention, the storage body may include a temperature controller.

  In the first or second aspect of the present invention, the molecular sieve membrane is preferably any one of a zeolite membrane, a silica membrane, and a carbon membrane, or a combination thereof.

  The zeolite membrane, silica membrane, and carbon membrane may be subjected to a treatment for controlling the opening diameter and / or a treatment for imparting hydrophobicity.

  In the first or second aspect of the present invention, when the molecular sieve membrane is a zeolite membrane, the crystalline zeolite skeleton forming the pores of the zeolite membrane is preferably a ring having an oxygen 8-membered ring or less.

  In the first or second aspect of the present invention, when the molecular sieve membrane is a zeolite membrane, the zeolite membrane preferably contains CHA-type zeolite.

  3rd this invention supplies the mixed gas containing hydrogen and oxygen in the space of one surface side in one space of the molecular sieve membrane partitioned off by the molecular sieve membrane, and the other space in water etc. In addition, the hydrogen separation method is characterized in that hydrogen in the mixed gas is selectively permeated from one space of the molecular sieve membrane to the other space to directly separate the hydrogen from the mixed gas.

  In the present invention, hydrogen in the mixed gas can be selectively permeated from one space of the molecular sieve membrane to the other space by the effect of the molecular sieve and the driving force due to the partial pressure difference of hydrogen. Here, “one space” and “the other space” mean spaces on one side and the other side partitioned by a molecular sieve membrane. For example, when the inner space closed by the molecular sieve membrane is “one space” when the molecular sieve membrane is a closed system such as a cylinder, the outer space of the molecular sieve membrane corresponds to the “other space” .

  In the third aspect of the present invention, it is preferable to separate hydrogen in water at 10 ° C. or higher and 100 ° C. or lower.

  According to the hydrogen separator and the hydrogen separation method of the present invention, hydrogen can be efficiently separated in water using a molecular sieve membrane, and the occurrence of an explosion due to the reaction between hydrogen and oxygen can be prevented.

It is a figure for demonstrating the hydrogen separation method which concerns on this invention. It is a figure for demonstrating the hydrogen separation apparatus which concerns on this invention. It is a figure for demonstrating a molecular sieve membrane. It is FIG. (1) for demonstrating the hydrogen separator of this invention which concerns on other embodiment. It is FIG. (2) for demonstrating the hydrogen separator of this invention which concerns on other embodiment. It is FIG. (3) for demonstrating the hydrogen separator of this invention which concerns on other embodiment. It is FIG. (4) for demonstrating the hydrogen separator of this invention which concerns on other embodiment. It is FIG. (5) for demonstrating the hydrogen separator of this invention which concerns on other embodiment. It is FIG. (6) for demonstrating the hydrogen separator of this invention which concerns on other embodiment. It is FIG. (The 7) for demonstrating the hydrogen separator of this invention which concerns on other embodiment. It is a figure for demonstrating the apparatus used in the Example.

1. Hydrogen Separation Method As shown in FIG. 1, the hydrogen separation method according to the present invention includes one of the space (space A) and the other space (space B) of the molecular sieve membrane partitioned by the molecular sieve membrane. A mixed gas containing hydrogen and oxygen is supplied into the space (space A) into water or the like, and the partial pressure difference of hydrogen is used as a driving force to drive one space (space A) to the other space (space B). ) To selectively separate hydrogen from the mixed gas by selectively permeating hydrogen in the mixed gas.

  Here, the “partial pressure difference” refers to a gas pressure difference between the space A and the space B.

  The space A is filled with water or the like, and a mixed gas containing hydrogen and oxygen is supplied thereto. Hydrogen and oxygen are generated by a water splitting reaction using a photocatalyst. The mixed gas may contain water vapor and the like in addition to hydrogen and oxygen.

  For example, the photocatalyst is dispersed in the water in the space A, or the photocatalyst molded body is immersed in the water in the space A, and the photocatalyst is irradiated with light to cause a water splitting reaction by the photocatalyst to generate hydrogen in the space A. By generating oxygen and oxygen, a mixed gas containing hydrogen and oxygen can be supplied into water or the like.

The kind of photocatalyst used in the present invention is not particularly limited, and any photocatalyst that can cause a water splitting reaction is applicable. As a photocatalyst, for example, titanium dioxide, strontium titanate, barium titanate, sodium titanate, cadmium sulfide, zirconium dioxide, α-Fe ₂ O ₃ , K ₄ Nb ₆ O ₁₇ , Rb ₄ Nb ₆ O ₁₇ , K ₂ Rb Semiconductors such as ₂ Nb ₆ O ₁₇ , Pb _1-x K _2x NbO ₆ (0 <x <1), and as a co-catalyst, metals such as platinum, palladium, rhodium, ruthenium, NiO _x , RuO _x , RhO There may be mentioned those carrying _{x and the} like. Moreover, you may use a photocatalyst in combination of 2 or more types. Similarly, two or more promoters may be used in combination.

  The molecular sieve membrane is in contact with water or the like in the space A, and among the mixed gas containing hydrogen and oxygen supplied into the water or the like, the hydrogen passes through the molecular sieve membrane and the space B While oxygen easily permeates, oxygen or the like is difficult to permeate the molecular sieve membrane because of its size, and remains in the space A. Thereby, hydrogen can be selectively separated directly from a mixed gas in water or the like.

  The partial pressure difference of hydrogen as a driving force is, for example, a method of pressurizing the gas in the space A and setting the space B to atmospheric pressure or reduced pressure, or flowing a sweep gas, and the gas in the space A as normal pressure. Can be generated by a method of reducing the pressure or flowing a sweep gas. When the sweep gas is allowed to flow into the space B, the hydrogen concentration in the space B can be reduced, so that even if the gas pressure in the space A is normal pressure, a hydrogen partial pressure difference can be ensured.

  In this case, the molecular sieving membrane refers to a membrane that selectively permeates molecules by molecular sieving ability. In the present invention, any membrane that has a hydrogen permeability higher than oxygen may be used. Details will be described later.

  In the above hydrogen separation method, it is preferable to perform the hydrogen separation while irradiating the photocatalyst filled with water or the like with sunlight to generate hydrogen and oxygen. In this case, the lower limit of the temperature of water or the like is preferably 10 ° C or higher, more preferably 40 ° C or higher, and the upper limit is preferably 100 ° C or lower, more preferably 95 ° C or lower. By setting the temperature of water or the like to 10 ° C. or higher and 100 ° C. or lower, there is little influence of freezing or water vapor, and hydrogen can be separated more efficiently. In order to perform hydrogen separation efficiently, it is preferable to perform temperature management with a temperature controller such as a water temperature adjusting device.

  The pressure in the hydrogen separation method is not particularly limited as long as a partial pressure difference of hydrogen as a driving force is obtained, but the lower limit of the gas pressure in the space A is usually at least atmospheric pressure, preferably at least 0.11 MPa, more preferably 0. .12 MPa, more preferably 0.15 MPa, while the upper limit is usually 5 MPa or less, preferably 4 MPa or less, more preferably 3 MPa, and even more preferably 1 MPa or less. On the other hand, the lower limit of the pressure in the space B on the permeate side is usually 0 MPa or more, preferably 0.00001 MPa or more, more preferably 0.0001 MPa or more, and further preferably 0.001 MPa or more, while the upper limit is usually 5 MPa or less. The pressure is preferably 4 MPa or less, more preferably 3 MPa, and still more preferably 1 MPa or less. Further, the partial pressure difference of the gas between the space A and the space B is not usually limited, but the lower limit is usually 0.001 MPa or more, preferably 0.002 MPa or more, more preferably 0.005 MPa or more, and further preferably 0.01 MPa. On the other hand, the upper limit is usually 5 MPa or less, preferably 4 MPa or less, more preferably 3 MPa, and still more preferably 1 MPa or less. In the present invention, the pressure (Pa) is an absolute pressure unless otherwise specified.

  When the sweep gas is allowed to flow into the space B, the hydrogen partial pressure in the space B only needs to be lower than the hydrogen partial pressure in the space A. Alternatively, as described above, the pressure may be reduced instead of flowing the sweep gas.

  The generation rate of hydrogen and oxygen generated from the photohydrolysis of the space A in the hydrogen separation method is not particularly limited because it depends on the performance of the photohydrolysis catalyst and the membrane.

  As described above, the hydrogen separation method according to the present invention directly separates hydrogen and oxygen supplied into water or the like by water splitting reaction of the photocatalyst in water or the like. Here, hydrogen and oxygen present in water or the like are less likely to explode than when present in a dry atmosphere (for example, in the air). That is, according to the hydrogen separation method of the present invention, hydrogen can be efficiently separated using a molecular sieve membrane in water or the like, and an explosion caused by the reaction between hydrogen and oxygen can be performed without using a dilution gas. It can also be prevented.

2. Hydrogen separation device A hydrogen separation device capable of implementing the above-described hydrogen separation method will be described. The form of the hydrogen separator according to the present invention is not particularly limited as long as hydrogen can be appropriately separated in water or the like.

2.1. Hydrogen separator 100
FIG. 2 is a diagram schematically showing a longitudinal section of the hydrogen separator 100 of the present invention according to an embodiment. As shown in FIG. 2, the hydrogen separation device 100 is a device for separating hydrogen from a mixed gas 1 containing hydrogen and oxygen that can be generated by water splitting of a photocatalyst, and includes a porous substrate 11 and the porous substrate 11. A hydrogen separator 10 having a molecular sieve membrane 12 formed on the outside, a recovery port 21 for recovering hydrogen separated from the mixed gas 1, and a discharge port 22 for discharging a gas other than hydrogen are provided. And a storage body 20 that can store the hydrogen separator 10. The storage body 20 is supplied or filled with water 5 or the like, and the mixed gas 1 is present in the water 5 or the like. At least a part of the body 10 is impregnated in the water 5 or the like, and hydrogen can be separated from the water 5 to the recovery port 21 via the hydrogen separator 10.

2.1.1. Hydrogen separator 10
FIGS. 3A and 3B show an example of the hydrogen separator 10. FIG. 3 (A) is a diagram schematically showing the appearance of the hydrogen separator 10, and FIG. 3 (B) is a diagram schematically showing a IIIB-IIIB cross section of FIG. 3 (A). As shown in FIG. 3, the hydrogen separator 10 includes a substantially cylindrical porous substrate 11 in which one end (upper end) of the hollow portion is opened and the other end (lower end) is closed, and the porous substrate 11. And a molecular sieve membrane 12 formed on the outside (outer wall surface).

  The porous substrate 11 functions as a support that supports the molecular sieve membrane 12. The material which comprises the porous base | substrate 11 is not specifically limited, Various materials, such as glass, ceramics, a metal, a carbon molding, or resin, are applicable. In the case of a ceramic support, any porous inorganic substance having a chemical stability capable of crystallizing zeolite in the form of a film on its surface or the like may be used. Specific examples include ceramic sintered bodies such as silica, α-alumina, γ-alumina, mullite, zirconia, titania, yttria, silicon nitride, and silicon carbide.

  Of these, silica, α-alumina, γ-alumina, and mullite are preferable. The reason why these are preferable is that the molecular sieve membrane 12 is supported on the porous substrate 11 with high adhesion.

  In the present invention, the porous substrate 11 itself does not need to have molecular sieving ability. The porous substrate 11 is provided with fine pores (holes, voids) communicating from the outer wall side toward the inner wall side. A well-known porous substrate 11 having pores can be used.

  The lower limit of the porosity of the porous substrate 11 is usually 20% or more, preferably 25% or more, more preferably 30% or more, while the upper limit is usually 80% or less, preferably 60% or less, more preferably. 50% or less. Further, the lower limit of the average pore diameter of the porous substrate 11 is usually 0.01 μm or more, preferably 0.05 μm or more, more preferably 0.1 μm or more, while the upper limit is 20 μm or less, preferably 10 μm or less, more Preferably it is 5 micrometers or less. With the porous substrate 11 having such pores, the molecular sieve membrane 12 can be adequately supported with sufficient strength, and the hydrogen that has permeated the molecular sieve membrane 12 can be adequately adequate on the inner wall side. Permeable at speed. In addition, the porosity and average pore diameter of the porous substrate 11 can be easily specified by a mercury intrusion method, a cross-sectional scanning electron microscope (SEM) observation, or the like. The porosity can also be calculated from volume and mass using true specific gravity.

  Among these, the lower limit of the maximum diameter of the opening of the through-hole from one surface to the other surface of the porous substrate 11 when forming the silica film as the molecular sieve film 12 is usually 1 nm or more, preferably 1.5 nm. That's it. On the other hand, the upper limit is usually 10 nm or less, preferably 8 nm or less. Moreover, all the penetrating parts extending from one surface to the other surface may have the same pore diameter. For example, as described in Japanese Patent Application Laid-Open No. 2005-270887, partially or stepwise different pore diameters are used. A thing may be used.

  The molecular sieve membrane 12 is a thin layer formed on the outer side (outer surface) of the porous substrate 11. The form of the molecular sieve membrane 12 is not particularly limited as long as the molecular sieve ability can be appropriately exhibited.

  In the present invention, the molecular sieve membrane 12 is preferably any one of a zeolite membrane, a silica membrane, and a carbon membrane, or a combination thereof. Since these have higher hydrogen permeability than oxygen, they can function appropriately as a membrane for efficiently separating hydrogen from a mixed gas containing hydrogen and oxygen.

  Here, when a zeolite membrane is used as the molecular sieve membrane 12, the zeolite is preferably an aluminosilicate, but Ga, Fe, B, Ti, Zr, Sn, Zn, instead of Al, unless the membrane performance is greatly impaired. A metallic element such as Ga, Fe, B, Ti, Zr, Sn, Zn, or P may be included together with Al. The skeleton of the crystalline zeolite forming the pores of the zeolite membrane is preferably an oxygen 8-membered ring or less. Examples of the zeolite structure include AEI, AFG, ANA, CHA, DDR, EAB, ERI, ESV. , FAR, FRA, GIS, ITE, KFI, LEV, LIO, LOS, LTA, LTN, MAR, PAU, RHO, RTH, SOD, STI, TOL, UFI, and the like. Among these, it is preferable to use a membrane composed of AEI, CHA, DDR, ERI, KFI, LEV, PAU, RHO, RTH, SOD, LTA, UFI type zeolite, and CHA, DDR, RHO, SOD type zeolite. More preferably, a constructed film is used. Among these, it is particularly preferable to use a membrane composed of CHA-type zeolite from the viewpoint of more efficiently separating hydrogen from a mixed gas containing hydrogen and oxygen.

  In the present specification, the value of n of the zeolite having an oxygen n-membered ring is such that the number of oxygen elements is the largest among the pores composed of the zeolite skeleton and the T element (elements other than oxygen constituting the skeleton). Point to something big. Moreover, the structure of a zeolite is shown by the code | symbol which prescribes | regulates the structure of the zeolite which International Zeolite Association (IZA) defines as above-mentioned.

  Further, the molecular sieve membrane 12 may be subjected to a treatment for more effectively controlling the opening diameter, and may be subjected to a treatment for improving hydrophobicity (for example, International Publication No. 2013/125661). (See the silylation treatment described in the pamphlet). When such a zeolite membrane is used, hydrogen can be separated more efficiently. Further, since the CHA-type zeolite can synthesize a high-silica zeolite membrane, it is relatively hydrophobic in the zeolite and is suitable when the molecular sieve membrane 12 is immersed in water as in the present invention. That is, when the molecular sieving membrane 12 is hydrophobic, gas can be efficiently permeated even if it contacts with water 5 or the like, and hardly deteriorates in water 5 or the like. Can be maintained.

  In addition, when synthesizing a zeolite membrane, an organic template (structure directing agent) can be used as necessary. However, there is no particular limitation as long as it is a template capable of producing a target zeolite structure. If synthesis is possible, it may not be used.

  When a silica film is used as the molecular sieve film 12, the silica content in the silica film is not particularly limited as long as the effects of the present invention are not significantly impaired. For example, in the silicon oxide composition, all positive elements including silicon are included. The ratio of silicon to is usually 50 mol% or more.

  The silica film is formed on the porous substrate 11 by a sol-gel method, a CVD method, a polymer precursor method, or the like. In the sol-gel method, a silica film can be formed by reacting a metal alkoxide and water on the porous substrate 11 to form a gel from hydrolysis and dehydration condensation. Further, in the counter diffusion CVD method, for example, in the case of a porous cylindrical substrate, oxygen is circulated on the inner side, a silica source is circulated on the outer side, and an amorphous silica layer is deposited in the pores of the substrate to form a silica film. A film can be formed. In the polymer precursor method, after a silica precursor such as alkoxysilane or polysilazane is coated on the porous substrate 11, a silica film can be formed by heat treatment.

  When a carbon film is used as the molecular sieve film 12, the carbon film precursor solution is dip-coated (dip-coated) on the porous substrate 11, heat-treated at about 600 to 800 ° C., and dried to obtain a carbon film. Examples of the carbon film precursor include aromatic polyimide, polypyrrolone, polyfurfuryl alcohol, polyvinylidene chloride, phenol resin, lignin derivative, wood tar, bamboo tar, and the like. Moreover, as a solvent, organic solvents, such as tetrahydrofuran, acetone, methanol, ethanol, N-methylpyrrolidone, can be used conveniently.

  The film thickness of the molecular sieve membrane 12 is not particularly limited, but is usually 0.01 μm to 30 μm, preferably 0.01 μm to 20 μm, more preferably 0.01 μm to 10 μm for a zeolite membrane, and from a single layer for a silica membrane. Or a film composed of two or more layers, and the thickness is usually 1 nm to 10 μm, preferably 1 nm to 5 μm, more preferably 1 nm to 1 μm, and the carbon film is usually 0.05 μm to 5 mm, preferably Is 0.1 μm to 2.5 mm, more preferably 0.1 μm to 500 μm, but it is preferable that the film thickness is thin as long as the film performance is not significantly impaired. The film thickness can be measured using a scanning electron microscope (SEM).

  The method for forming the molecular sieve film 12 on the surface of the porous substrate 11 is not particularly limited. For example, (1) a method of fixing a substance that can constitute the molecular sieve membrane 12 to the surface of the porous substrate 11 with a binder or the like, and (2) a porous slurry or solution in which a substance that can constitute the molecular sieve membrane 12 is dispersed. A method of impregnating the substrate 11 to fix the substance on the surface of the porous substrate 11; and (3) crystallizing a substance (in particular, zeolite) that can form the molecular sieve film 12 on the surface of the porous substrate 11 into a film. And the like (for example, see International Publication No. 2013/125660 pamphlet).

  The hydrogen separator 10 is open at one end and closed at the other end. The other end may be closed by the molecular sieve membrane 12 described above.

2.1.2. Storage body 20
The storage body 20 has a recovery port 21 for recovering hydrogen separated from the mixed gas 1 and a discharge port 22 for discharging gas other than hydrogen, and stores the hydrogen separator 10 described above. Can do. Further, in the state where the hydrogen separator 10 is stored, the opening of the hydrogen separator 10 is connected to the recovery port 21 of the storage body 20, and the hydrogen selectively separated by the hydrogen separator 10 is removed from the recovery port 21. It is possible to collect through. On the other hand, the storage body 20 is provided with a discharge port 22 outside the hydrogen separator 10 separately from the recovery port 21, and the gas (oxygen) that has not permeated the hydrogen separator 10 from the discharge port 22. Etc.) are discharged.

  When the hydrogen separator 100 is in operation, the storage body 20 is filled with water 5 or the like, and when the hydrogen separator 10 is stored, at least a part of the hydrogen separator 10 is impregnated with the water 5 or the like. Become. Here, the water etc. 5 includes the mixed gas 1 generated by the water splitting reaction of the photocatalyst, and the mixed gas 1 can reach the hydrogen separator 10 in the water etc. 5. Of the mixed gas 1 that has reached the hydrogen separator 10, hydrogen easily permeates the molecular sieve membrane 12 and selectively permeates the inside of the hydrogen separator 10, while gases other than hydrogen (oxygen, etc.) 12 is still present in the water 5 or the like and is discharged from the discharge port 22 to the outside of the system. The driving force at this time is a partial pressure difference between hydrogen on the water 5 side and the hydrogen separator 10 side. Molecules having a larger dynamic molecular diameter than hydrogen, such as oxygen, are difficult to permeate the molecular sieve membrane 12 because of their slow permeation rate.

2.2. Hydrogen separator 200
FIG. 4 shows a longitudinal sectional view of a hydrogen separator 200 according to another embodiment of the present invention. In the figure, the same members as those of the hydrogen separator 100 are denoted by the same reference numerals, and description thereof is omitted. The hydrogen separator 200 is different from the hydrogen separator 100 in that the photocatalyst molded body 30 is provided in water 5 or the like 5 filled in the storage body 20.

  The photocatalyst molded body 30 is a plate-shaped or sheet-shaped molded body having at least a photocatalytic layer on a substrate. Such a photocatalyst molded body 30 can be easily held in the storage body 20 as compared with the case where photocatalyst particles 40 described later are used. Further, when it is assumed that the photocatalyst replacement / recovery operation is performed, or from the viewpoint of manufacturing efficiency, the photocatalyst is fixed in advance, so that the operation becomes simpler. As shown in FIG. 4, in the hydrogen separation device 200, by irradiating the photocatalyst molded body 30 with light, the water 5 that contacts the photocatalyst molded body 30 is decomposed, and the water 5 contains hydrogen and oxygen. A mixed gas can be supplied. The storage body 20 is configured to be able to irradiate light to at least the photocatalyst molded body 30. For example, by using the storage body 20 having a light irradiation window (transparent window) on the wall surface facing the photocatalyst molded body 30, light can be irradiated from the window to the photocatalyst molded body 30, and water decomposition by the photocatalyst is performed. A reaction can occur.

  Although not shown in FIG. 4, it is possible to irradiate the photocatalyst molded body 30 with sufficient sunlight by using a reflecting mirror.

2.3. Hydrogen separator 300
FIG. 5 shows a longitudinal sectional view of a hydrogen separator 300 according to another embodiment of the present invention. In the figure, the same members as those of the hydrogen separator 100 are denoted by the same reference numerals, and description thereof is omitted. The hydrogen separation device 300 is different from the hydrogen separation device 100 in that the photocatalyst particles 40 are included in the water 5 or the like 5 filled in the storage body 20.

  In the hydrogen separator 300, the storage body 20 is filled with water or the like 5 containing the photocatalyst particles 40. In this case, by irradiating the photocatalyst particles 40 with light, the water or the like 5 in contact with the photocatalyst particles 40 is decomposed, and a mixed gas containing hydrogen and oxygen can be supplied into the water or the like. In addition, in this form, in order to disperse | distribute the photocatalyst particle 40 uniformly in water, the stirring means may be provided in the storage body 20. FIG. Moreover, it is preferable that the storage body 20 is configured to be able to take in light from multiple directions. For example, by setting it as the storage body 20 provided with the several light irradiation window (transparent window), light can be irradiated from the said several window and the water splitting reaction by a photocatalyst can be accelerated | stimulated.

2.4. Hydrogen separator 400
FIG. 6 shows a longitudinal sectional view of a hydrogen separator 400 according to another embodiment of the present invention. In the figure, the same members as those of the hydrogen separator 100 are denoted by the same reference numerals, and description thereof is omitted. In the hydrogen separator 400, the storage body 20 and the storage body 20 ′ are connected, a water splitting reaction is caused by a photocatalyst in the storage body 20 ′, and the mixed gas 1 containing hydrogen and oxygen generated by the water splitting reaction is treated with water. It differs from the hydrogen separation apparatus 100 in that it can be supplied to the inlet 23 of the storage body 20 together with the etc. 5.

  Thus, in this invention, you may perform the water splitting reaction by a photocatalyst, and the isolation | separation collection | recovery of hydrogen by a hydrogen separator in a separate storage body. However, in this case, in order to prevent an explosion due to a reaction between hydrogen and oxygen, it is necessary to devise a technique for avoiding an explosion risk such as filling the space between the storage bodies with a liquid such as water.

2.5. Hydrogen separator 500
FIG. 7 shows a longitudinal sectional view of a hydrogen separator 500 according to another embodiment of the present invention. In the figure, the same members as those of the hydrogen separator 100 are denoted by the same reference numerals, and description thereof is omitted. The hydrogen separation device 500 is configured such that oxygen or the like discharged from the discharge port 22 of the storage body 20 flows through the piping and is reintroduced from the introduction port 23 to the storage body 20. Different from the device 100.

  In the present invention, it may be difficult to separate all of the hydrogen generated by the water splitting reaction with the hydrogen separator 10, and part of the hydrogen will be discharged from the discharge port 22. According to the hydrogen separator 500, the discharged hydrogen can be returned again into the storage body 20, so that the hydrogen recovery rate can be improved.

  Although not shown in FIG. 7, the hydrogen separation apparatus 500 may be provided with a purge port that can adjust the pressure in the storage body 20 at any location of the storage body 20. By installing a pressure-adjustable purge port in the storage body 20, the oxygen concentration in the storage body 20 can be adjusted, hydrogen permeation of the molecular sieve membrane 12 can be made advantageous, and the pressure adjustment in the storage body 20 Is also possible.

2.6. Hydrogen separator 600
FIG. 8 shows a longitudinal sectional view of a hydrogen separator 600 according to another embodiment of the present invention. In the figure, the same members as those of the hydrogen separator 100 are denoted by the same reference numerals, and description thereof is omitted. The hydrogen separator 600 is different from the hydrogen separator 100 in that a temperature controller 50 is provided outside the housing 20.

  According to the hydrogen separator 600, the temperature controller 50 is provided outside the storage body 20, so that the temperature of the water 5 inside the storage body 20 can be adjusted by the temperature controller 50. As described above, by performing hydrogen separation with water 5 or the like of 10 ° C. or higher and 100 ° C. or lower, hydrogen can be more efficiently separated at an optimum temperature according to the properties of the molecular sieve membrane 12. The temperature controller 50 may be provided inside the storage body 20.

2.7. Hydrogen separator 700
FIG. 9 shows a longitudinal sectional view of a hydrogen separator 700 according to another embodiment of the present invention. In the figure, the same members as those of the hydrogen separator 100 are denoted by the same reference numerals, and description thereof is omitted. The hydrogen separator 700 is filled with water or the like 5 containing the mixed gas 1 inside the hydrogen separator 10 so that hydrogen can be selectively separated from the inside of the hydrogen separator 10 to the outside. 100 is different.

  In the hydrogen separator 700, the hydrogen separator 10 is open at both one end and the other end, and the inlet 23 and the outlet 22 provided in the storage body 20 are one end and the other end of the hydrogen separator 10, respectively. It is connected to the. The storage body 20 is provided with a recovery port 21 outside the hydrogen separator 10 in addition to the introduction port 23 and the discharge port 22. In the hydrogen separator 700, hydrogen is selectively permeated to the outside of the hydrogen separator 10 through the molecular sieve membrane 12 by circulating water 5 containing the mixed gas 1 inside the hydrogen separator 10. Thus, hydrogen can be separated and recovered through the recovery port 21.

2.8. Hydrogen separator 800
FIG. 10 is a longitudinal sectional view of a hydrogen separator 800 according to another embodiment of the present invention. In the figure, the same members as those of the hydrogen separator 200 are denoted by the same reference numerals, and description thereof is omitted. The hydrogen separator 800 is different from the hydrogen separator 200 in that the hydrogen separator 10 is flat and is installed so as to cover the water surface in the storage body 20, and the side tube 24 is installed.

  In the hydrogen separator 10, the porous support 11 and the molecular sieve membrane 12 have a flat plate shape and are joined to the storage body 20. In order to avoid explosion, in order not to create a space between the container 20 and the molecular sieve membrane 12, the height of the water surface in the container 20 can be controlled by the water column 6 filled in the side tube 24. is there.

  The photocatalyst compact 30 is a compact as described in the hydrogen separator 200, but the photocatalyst particles 40 used in the hydrogen separator 300 can be used instead of the photocatalyst compact 30. Further, as in the hydrogen separator 400, the water splitting storage body 20 'using a photocatalyst and the storage body 20 for separating generated hydrogen may be connected and installed as separate storage bodies. Further, the temperature controller 50 may be provided outside or inside the housing 20 like the hydrogen separator 600. In addition, by using a reflecting mirror like the hydrogen separator 200, it is possible to irradiate the photocatalyst with sufficient sunlight. Since hydrogen and oxygen collect on the water surface of the container 20 by buoyancy, gas separation of hydrogen and oxygen can be performed more efficiently.

  As described above, according to the hydrogen separators 100 to 800, the above-described hydrogen separation method can be appropriately performed, and hydrogen can be efficiently separated using a molecular sieve membrane in water or the like. Explosion due to the reaction between hydrogen and oxygen can be prevented without using a gas.

  In the above description, the form in which the storage body 20 is filled with the photocatalyst, the water 5 and the like has been described. However, the present invention is not limited to this form. For example, seawater is supplied into the storage body 20. Alternatively, it can be filled.

  In the above description, the embodiment in which one hydrogen separator 10 is provided in the storage body 20 has been described. However, the present invention is not limited to this embodiment. It is also possible to provide a plurality of hydrogen separators 10 in the storage body 20. By providing the plurality of hydrogen separators 10, the hydrogen separation efficiency and the recovery rate can be improved.

  Moreover, in the above description, although the form provided with the substantially cylindrical or flat-plate-shaped hydrogen separator 10 was demonstrated as a hydrogen separator, this invention is not limited to the said form. The form of the hydrogen separator 10 is not particularly limited as long as hydrogen can be separated from the mixed gas in the liquid, and any form that can partition the space A and the space B as shown in FIG. Any form may be used.

  In the above description, the hydrogen separator 10 has been described with respect to the form in which the molecular sieve membrane 12 is provided on the outer side (outer wall surface) of the porous substrate 11, but the present invention is not limited to this form. In the hydrogen separator 10, the molecular sieve membrane 12 may be provided on the inner side (inner wall surface) of the porous substrate 11 or on both the inner side and the outer side.

  In the above description, the hydrogen separators 100 to 800 are individually described. However, the present invention may be a combination of components included in the hydrogen separators 100 to 800.

  Further, in the hydrogen separators 100 to 800 described above, “a hydrogen separator that is already filled with water or the like” will be described, and in the hydrogen separators 100 to 700 described above, a hydrogen separator is provided. Although the form "impregnated" with water etc. was demonstrated, this invention is not limited to the said form. By installing a hydrogen separator at an appropriate position in the storage body before the water is filled in the storage body, when the storage body is filled with water or the like, Hydrogen can be separated from the mixed gas therein. Also, hydrogen can be separated from a mixed gas in water or the like through the hydrogen separator even if the hydrogen separator is not simply “impregnated” into the charged water or the like but simply “contacted”. . As a form in which the hydrogen separator is brought into “contact” with water or the like, a form in which one surface side of the hydrogen separator is brought into contact with a water surface (liquid surface) such as water as in the hydrogen separator 800 can be cited.

  From this point of view, the following hydrogen separation device 900 (not shown) can be cited as a hydrogen separation device that can solve the problems of the present application and exhibit the effects specific to the present invention. That is, the hydrogen separator 900 is a hydrogen separator that separates hydrogen from the mixed gas 1 containing hydrogen and oxygen generated by water splitting of the photocatalyst, and is formed on at least one side of the porous substrate 11 and the porous substrate 11. A hydrogen separator 10 having a molecular sieve membrane 12 formed, a recovery port 21 connected to the hydrogen separator 10 for recovering hydrogen separated from the mixed gas 1 through the hydrogen separator 10, and hydrogen And a storage body 20 that stores the hydrogen separator 10. The storage body 20 is filled with water or a water-containing liquid (such as water 5). The hydrogen separator 10 is housed in a position where one surface side of the hydrogen separator 10 is in contact with the water 5 or the like, and the hydrogen separator 10 removes hydrogen from the mixed gas 1 existing in the water 5 or the like. It is characterized by separating. The details of each member provided in the hydrogen separator 900 are as described above, and a description thereof is omitted here.

  In addition, the structure which concerns on the above-mentioned hydrogen separator 100-800 can also be combined with the hydrogen separator 900 suitably.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not restrict | limited by a following example, unless the summary is exceeded.

1. Experimental Apparatus FIG. 11 schematically shows an experimental apparatus used in the examples.

  A storage body having an introduction port, a recovery port, and a discharge port was prepared. Further, a substantially cylindrical hydrogen separator having a molecular sieve membrane formed on the surface of the porous substrate, one end opened and the other end closed was prepared. A CHA zeolite membrane (manufactured by Mitsubishi Chemical Corporation) was used as the molecular sieve membrane.

  The hydrogen separator was stored in the prepared storage body. During storage, the opening of the hydrogen separator and the recovery port of the storage body were connected and fixed.

  In order to simulate hydrogen and oxygen generated from the photocatalyst, a pipe for supplying a supply gas was connected to the inlet of the storage body so that the gas could be supplied from the outside. The tip of the pipe in the container was connected to a sintered filter so that water bubbling was possible in the container.

  A pipe and a cooling pipe were connected to the outlet of the storage body so that the gas that did not permeate the hydrogen separator could be discharged.

  In addition, a temperature controller (heater) was installed outside the storage body so that the temperature of the storage body could be adjusted.

2. Experimental method (Example 1)
A gas permeation experiment using a molecular sieve membrane was performed on the gas in water by filling the container with water, supplying gas from the outside, and flowing a sweep gas into the hydrogen separator.

  In order to simulate the separation of hydrogen from a mixed gas containing hydrogen and oxygen, helium having a dynamic molecular diameter close to that of hydrogen and nitrogen having a dynamic molecular diameter substantially equal to that of oxygen were used (dynamic molecular diameter: (Hydrogen 0.29 nm, helium 0.26 nm, oxygen 0.35 nm, nitrogen 0.36 nm).

<Hydrogen separator>
As the hydrogen separator, a CHA-type zeolite membrane composite in which a CHA-type zeolite membrane was formed on the outside of the ceramic support by hydrothermal synthesis was used.

<Synthesis Method of CHA Type Zeolite Membrane Composite 1>
A ceramic support-CHA type zeolite membrane composite 1 was prepared by directly hydrothermally synthesizing CHA type zeolite on the ceramic support.

  A reaction mixture for hydrothermal synthesis was prepared as follows.

<Synthesis of aqueous reaction mixture>
A mixture of 10.5 g of 1 mol / L-NaOH aqueous solution (manufactured by Kishida Chemical Co., Ltd.), 7.0 g of 1 mol / L-KOH aqueous solution (manufactured by Kishida Chemical Co., Ltd.) and 100.6 g of demineralized water is mixed with aluminum hydroxide (Al ₂ O ₍ 33.5% by mass, manufactured by Aldrich) 0.88 g was added, followed by stirring to obtain a transparent solution. As an organic template, 2.36 g of an aqueous solution of N, N, N-trimethyl-1-adamantanammonium hydroxide (hereinafter referred to as “TMADAOH”) (containing 25% by mass of TMADAOH, manufactured by Seychem) was added, and After adding 10.5 g of colloidal silica (Snowtex 40, Nissan Chemical Co., Ltd.), the mixture was stirred for 2 hours to obtain an aqueous reaction mixture.

The composition (molar ratio) of this aqueous reaction mixture was SiO ₂ / Al ₂ O ₃ / NaOH / KOH / H ₂ O / TMADAOH = 1 / 0.066 / 0.15 / 0.1 / 100 / 0.04, a _{SiO 2 / Al 2 O 3 =} 15.

  As a ceramic support, a mullite tube PM (outer diameter 12 mm, inner diameter 9 mm) manufactured by Nikkato Co., Ltd. was cut into a length of 80 mm, washed with water with an ultrasonic cleaner, and dried.

As a seed crystal, the gel composition (molar ratio) of SiO ₂ / Al ₂ O ₃ / NaOH / KOH / H ₂ O / TMADAOH = 1 / 0.033 / 0.1 / 0.06 / 40 / 0.07, A CHA-type zeolite obtained by hydrothermal synthesis at 160 ° C. for 2 days for crystallization, followed by filtration, washing with water and drying was used. The support was immersed in a dispersion of the seed crystal in about 1% by mass of water for a predetermined time, and then dried at 100 ° C. for 5 hours or more to attach the seed crystal. The mass of the attached seed crystal was about 1 g / m ² .

  The support to which the seed crystal was attached was immersed in a Teflon (registered trademark) inner cylinder (200 ml) containing the aqueous reaction mixture in the vertical direction, and the autoclave was sealed, and allowed to stand at 160 ° C. for 48 hours. And heated under autogenous pressure. After the elapse of a predetermined time, the support-zeolite membrane composite was taken out of the reaction mixture after being allowed to cool, washed, and then dried at 100 ° C. for 5 hours or more.

This membrane composite was baked in air at 550 ° C. for 10 hours in an electric furnace manufactured by Yamato Scientific. At this time, the rate of temperature increase and the rate of temperature decrease were both 0.5 ° C./min. The mass of the CHA-type zeolite crystallized on the support, determined from the difference between the mass of the membrane composite after firing and the mass of the support, was 132 g / m ² .

<Gas permeation experiment>
Water was filled between the storage body and the CHA-type zeolite membrane composite 1, and a single component gas permeation experiment was performed for helium or nitrogen, respectively. The flow rate supplied to the helium or nitrogen storage body was 100 sccm, and the sweep gas argon was 50 sccm. The temperature adjustment was performed by installing a heater capable of adjusting the temperature outside the housing.

  The permeation amount of helium or nitrogen entrained in the sweep gas was quantified by 0n-line gas chromatography (manufactured by Agilent Technologies) after cooling with ice and trapping water vapor. The results are shown in Table 1 below.

(Reference Example 1)
Supply gas (carbon dioxide: 78 sccm, sweep gas argon 70 sccm) was passed at 120 ° C. for 1 hour to dry the CHA-type zeolite membrane composite 1.

  A single component gas permeation experiment was performed for helium or nitrogen without filling water between the housing and the CHA-type zeolite membrane composite 1. The flow rate supplied into the helium or nitrogen storage body was 50 sccm, and the argon of the sweep gas was 70 sccm.

  The permeation amount of helium or nitrogen entrained in the sweep gas was quantified with a gas flow meter (manufactured by Brooks Instruments) and 0n-line gas chromatography (manufactured by Agilent Technologies). The results are shown in Table 1 below.

  From the results shown in Table 1, it can be seen that when a gas permeation experiment is performed in water using a molecular sieve membrane, the permeation amount of helium is greater than that of nitrogen. Further, it can be seen from the permeation ratio between helium and nitrogen that the separation in water (Example 1) shows the same separation performance as the separation not in water (Reference Example 1).

  Moreover, when water is heated from 50 degreeC to 80 degreeC with a temperature controller (heater), it turns out that permeation | transmission amount increases, maintaining separation performance.

(Example 2)
In the same manner as in Example 1, a gas permeation experiment using a molecular sieve membrane was performed on the gas in water by filling the storage body with water, supplying gas from the outside, and flowing a sweep gas into the hydrogen separator.

  In addition, gas separation experiments using mixed gas were also conducted. In order to simulate the separation of hydrogen from a mixed gas containing hydrogen and oxygen, a mixed gas containing hydrogen and nitrogen was used. Since nitrogen has almost the same conversion factor and dynamic molecular diameter as oxygen, nitrogen was used instead of oxygen (conversion factor: oxygen: 0.99, nitrogen: 1.00, dynamic molecular diameter : Oxygen 0.35 nm, nitrogen 0.36 nm). The mixed gas of hydrogen and nitrogen was supplied into the storage body using two kinds of mass flow controllers (Brooks Instrument Co., Ltd.) so that the flow rate ratio was 2: 1.

<Hydrogen separator>
As the hydrogen separator, a CHA-type zeolite membrane composite 2 in which a CHA-type zeolite membrane was formed on the outside of the ceramic support by hydrothermal synthesis was used.

<Synthesis Method of CHA Type Zeolite Membrane Composite 2>
A ceramic support-CHA type zeolite membrane composite 2 was prepared by directly hydrothermally synthesizing CHA type zeolite on the ceramic support.

  A reaction mixture for hydrothermal synthesis was prepared as follows.

<Synthesis of aqueous reaction mixture>
Aluminum hydroxide (Al ₂ O ₃ 53) mixed with 1.4 g of 1 mol / L-NaOH aqueous solution (manufactured by Kishida Chemical Co., Ltd.), 5.8 g of 1 mol / L-KOH aqueous solution (manufactured by Kishida Chemical Co., Ltd.) and 114 g of demineralized water. 0.5 mass% (manufactured by Aldrich Co.) was added, and then stirred to obtain a transparent solution. As an organic template, 2.4 g of TMADAOH aqueous solution (containing 25% by mass of TMADAOH, manufactured by Seychem) was added, and 10.8 g of colloidal silica (Snowtex 40 manufactured by Nissan Chemical Co., Ltd.) was further added, followed by stirring for 1 hour. An aqueous reaction mixture was obtained.

The composition (molar ratio) of this aqueous reaction mixture was SiO ₂ / Al ₂ O ₃ / NaOH / KOH / H ₂ O / TMADAOH = 1 / 0.014 / 0.02 / 0.08 / 100 / 0.04, a _{SiO 2 / Al 2 O 3 =} 70.

  As the ceramic support, a porous alumina tube (outer diameter 12 mm, inner diameter 9 mm) was cut to a length of 80 mm, washed with water with an ultrasonic cleaner, and dried.

As a seed crystal, the gel composition (molar ratio) of SiO ₂ / Al ₂ O ₃ / NaOH / KOH / H ₂ O / TMADAOH = 1 / 0.033 / 0.1 / 0.06 / 40 / 0.07, A CHA-type zeolite obtained by hydrothermal synthesis at 160 ° C. for 2 days for crystallization, followed by filtration, washing with water and drying was used. The support was immersed in a dispersion of the seed crystal in about 1% by mass of water for a predetermined time, and then dried at 140 ° C. for 1 hour or longer to attach the seed crystal. The mass of the attached seed crystal was about 1 g / m ² .

  The support to which the seed crystals were attached was immersed in a Teflon (registered trademark) inner cylinder (200 ml) containing the aqueous reaction mixture in the vertical direction, and the autoclave was sealed, and left standing at 180 ° C. for 18 hours. And heated under autogenous pressure. After the elapse of a predetermined time, the support-zeolite membrane composite was taken out of the reaction mixture after being allowed to cool, washed, and dried at 120 ° C. for 1 hour or longer.

This membrane composite was baked in the air at 500 ° C. for 14 hours in an electric furnace manufactured by Yamato Scientific Co., Ltd. At this time, the rate of temperature increase and the rate of temperature decrease were both 0.5 ° C./min. The mass of the CHA-type zeolite crystallized on the support, determined from the difference between the mass of the membrane composite after firing and the mass of the support, was 80 g / m ² .

<Gas permeation experiment>
Water was filled between the storage body and the CHA-type zeolite membrane composite 2, and a single component gas permeation experiment was conducted for hydrogen or nitrogen, respectively. The flow rate supplied into the container was 100 sccm, and the sweep gas argon was 50 sccm. The temperature adjustment was performed by installing a heater capable of adjusting the temperature outside the housing.

  The permeation amount of hydrogen or nitrogen entrained in the sweep gas was quantified by 0n-line gas chromatography (manufactured by Agilent Technologies) after cooling with ice and trapping water vapor. The results are shown in Table 2 below.

<Gas separation experiment>
Water was filled between the storage body and the CHA-type zeolite membrane composite 2, and a gas separation experiment was performed on a mixed gas of hydrogen / nitrogen = 2/1. The flow rate supplied into the container was 100 sccm, and the sweep gas argon was 50 sccm. The temperature adjustment was performed by installing a heater capable of adjusting the temperature outside the housing.

  The permeation amount and separation factor of hydrogen and nitrogen entrained in the sweep gas were determined by 0n-line gas chromatography (manufactured by Agilent Technologies) after cooling with ice and trapping water vapor. The results are shown in Table 3 below.

(Reference Example 2)
Supply gas (carbon dioxide: 78 sccm, sweep gas argon 70 sccm) was passed at 120 ° C. for 1 hour to dry the CHA-type zeolite membrane composite 2.

  Without filling water between the housing and the CHA-type zeolite membrane composite 2, a hydrogen or nitrogen single component gas permeation experiment and a gas separation experiment of a mixed gas of hydrogen / nitrogen = 2/1 were conducted. The flow rate supplied into the container was 50 sccm, and the argon of the sweep gas was 70 sccm.

  The permeation amount of hydrogen or nitrogen entrained in the sweep gas was quantified with a gas flow meter (manufactured by Brooks Instruments) and 0n-line gas chromatography (manufactured by Agilent Technologies). The separation factor was quantified by 0n-line gas chromatography. The results are shown in Table 2 or 3 below.

  From the results shown in Table 2, it can be seen that when a gas permeation experiment is performed in water using a molecular sieve membrane, the permeation amount of hydrogen is larger than that of nitrogen. Moreover, it can be seen from the permeation ratio between hydrogen and nitrogen that the separation in water (Example 2) shows substantially the same separation performance as the separation not in water (Reference Example 2).

  In addition, when water is heated from 50 ° C. to 80 ° C. by a temperature controller (heater), it can be seen that in Example 2, the permeation amount increases while maintaining the separation performance as in Example 1.

  Further, from the results shown in Table 3, when a gas separation experiment of a mixed gas of hydrogen / nitrogen = 2/1 was performed in water using a molecular sieve membrane, separation in water (Example 2) It can be seen that the separation performance is not substantially the same as that of the separation (Reference Example 2). The reason why the separation factor in Table 3 is larger than the permeation ratio in Table 2 is that the partial pressure of hydrogen in the mixed gas is different from the partial pressure in the case of a single component gas.

  From the above results, among one space and the other space of the molecular sieve membrane partitioned by the molecular sieve membrane, a mixed gas containing hydrogen and oxygen is supplied in one space in water, and one space of the molecular sieve membrane is provided. It can be said that hydrogen in the mixed gas can be selectively permeated into the other space to directly separate the hydrogen from the mixed gas. Further, by separating hydrogen and oxygen in water, it is possible to avoid an explosion due to a reaction between hydrogen and oxygen.

  INDUSTRIAL APPLICABILITY The present invention can be used as a technique for safely separating hydrogen from a mixed gas containing hydrogen and oxygen in a water splitting reaction process using a photocatalyst.

DESCRIPTION OF SYMBOLS 1 Mixed gas 5 Water etc. 6 Water column 10 Hydrogen separator 11 Porous substrate 12 Molecular sieve membrane 20 Storage body 21 Recovery port 22 Discharge port 23 Inlet 24 Side tube 30 Photocatalyst compact 40 Photocatalyst particle 50 Temperature controller 100-900 Hydrogen separation apparatus

Claims (9)

A hydrogen separator for separating hydrogen from a mixed gas containing hydrogen and oxygen generated by water splitting of a photocatalyst,
A hydrogen separator having a porous substrate and a molecular sieve membrane formed on at least one side of the porous substrate;
Connected to the hydrogen separator, having a recovery port for recovering hydrogen separated from the mixed gas through the hydrogen separator, and a discharge port for discharging gas other than hydrogen, and A storage body for storing the hydrogen separator;
With
When the storage body is filled with water or a water-containing liquid (hereinafter referred to as “water etc.”), the hydrogen separator is stored in a position where one side of the hydrogen separator contacts the water or the like. And
The hydrogen separator separates the hydrogen from the mixed gas existing in the water or the like. An apparatus for separating hydrogen from a mixed gas containing hydrogen and oxygen that can be generated by water splitting of a photocatalyst,
A hydrogen separator comprising a porous substrate and a molecular sieve membrane formed outside or inside the porous substrate; and
A storage body having a recovery port for recovering hydrogen separated from the mixed gas and a discharge port for discharging a gas other than hydrogen, and capable of storing the hydrogen separator;
With
The container is filled with water or a water-containing liquid (hereinafter referred to as “water etc.”),
The mixed gas exists in the water or the like,
At least a part of the hydrogen separator is impregnated in the water or the like;
The hydrogen can be separated from the water or the like to the recovery port via the hydrogen separator,
Hydrogen separator.   The hydrogen separator according to claim 1, wherein the storage body further includes an inlet for the mixed gas in addition to the recovery port and the discharge port.   The hydrogen separator according to any one of claims 1 to 3, wherein a temperature controller is provided outside the storage body.   The hydrogen separator according to any one of claims 1 to 4, wherein the molecular sieve membrane is any one or a combination of a zeolite membrane, a silica membrane, and a carbon membrane.   The hydrogen separator according to claim 5, wherein the skeleton of the crystalline zeolite forming the pores of the zeolite membrane is an 8-membered ring or less ring.   The hydrogen separator according to claim 5 or 6, wherein the zeolite membrane contains CHA-type zeolite.   Of one space and the other space of the molecular sieve membrane partitioned by the molecular sieve membrane, a mixed gas containing hydrogen and oxygen in the one space is water or a water-containing liquid (hereinafter referred to as “water etc.”). A hydrogen separation method, wherein hydrogen in the mixed gas is selectively permeated from one space of the molecular sieve membrane to the other space to directly separate hydrogen from the mixed gas.   The hydrogen separation method according to claim 8, wherein hydrogen is separated in water at 10 ° C. or higher and 100 ° C. or lower.

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