JP2001198431A - Permeable membrane, method for preparing zeolite membrane, fuel cell system, steam reforming apparatus, electrolytic capacitor and separating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a permeable membrane that allows selectively to permeate hydrogen from a vapor of water or ethylene glycol, a fuel cell system and an electrolytic capacitor containing the permeable membrane. SOLUTION: The permeable membrane having a ratio between a hydrogen permeation speed and a water vapor permeation speed which is not less than a specific ratio is used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a membrane for selectively permeating hydrogen from water vapor and ethylene glycol. The permeable membrane is suitably used for gas separation or permeation under a condition in which a highly polar compound vapor such as water, ethylene glycol, γ-butyrolactone, and ammonia exists. The permeable membrane is, of course, a membrane for various gas permeation in the absence of a highly polar compound vapor,
Alternatively, it can be used as a liquid-permeable membrane.

[0002] The present invention also relates to the application of the permeable membrane and related techniques. The permeable membrane of the present invention can be used for applications such as fuel cells and electrolytic capacitors.

[0003] Fuel cells use hydrogen as fuel,
This hydrogen is obtained by directly receiving the supply of hydrogen or by reforming a hydrocarbon such as methanol, methane or gasoline with steam or the like. The system for supplying hydrogen directly
This is advantageous in that the structure of the system can be simplified. However, when a high-pressure hydrogen cylinder or a liquid hydrogen tank is used, safety and weight are problems. When a hydrogen storage alloy is used, price and weight are problems. Another problem is that the infrastructure for supplying hydrogen has not been established. On the other hand, the method of reforming hydrocarbons requires a reformer and the like, which complicates the structure of the system. However, it is considered that the fuel storage unit is lightweight and the maintenance of the fuel supply infrastructure is easier than hydrogen. When steam is used for reforming hydrocarbons, the following reaction occurs in the reformer.

[0004]

(Equation 1)

[0005] Since this reaction is an equilibrium reaction, if hydrogen and carbon dioxide can be selectively removed from the reformer, the reaction can be further promoted. Therefore, a membrane that selectively permeates hydrogen as a reaction product from water as a reaction raw material is extremely important.

[0006] A small amount of carbon monoxide is mixed into the reformed gas by the following shift reaction.

[0007]

(Equation 2)

[0008] Carbon monoxide is known to poison catalysts on fuel electrodes. Therefore, H is quickly released from the reforming reaction system.
If CO ₂ and CO ₂ can be removed, the generation of CO can be suppressed. Further, a membrane that selectively permeates hydrogen from carbon monoxide is more useful because it can remove carbon monoxide, which is a poisoning substance of the fuel electrode. Also in this case, if the membrane does not selectively transmit hydrogen than water, water coexisting in the reformed gas is adsorbed in the pores of the membrane, and the amount of permeated hydrogen decreases. Therefore, a membrane that selectively permeates hydrogen over water is also extremely important in separating hydrogen / carbon monoxide gas in the presence of water vapor.

The permeable membrane of the present invention can be used for an electrolytic capacitor. The electrolytic capacitor holds the electrolytic solution in a sealed container, and the electrolytic solution gradually decomposes during the operation of the electrolytic capacitor to generate hydrogen gas. The electrolytic capacitor was damaged by the pressure of the generated hydrogen gas. When the permeable membrane of the present invention is used, the life of the electrolytic capacitor can be sufficiently extended, and safety during use of the electrolytic capacitor can be secured.

[0010]

2. Description of the Related Art Conventionally, a palladium membrane has been known as a membrane through which hydrogen can selectively pass. For example, in steam reforming of methane, the reaction equilibrium can be significantly inclined to the product side by selectively permeating generated hydrogen. However, the hydrogen permeation mechanism of the palladium membrane is a dissolution / diffusion mechanism involving the dissociation of hydrogen. In order to increase the permeation rate to a practical level, hydrogen gas must be supplied at 300 ° C. or more and several tens of atmospheres. Due to the strictness of this transmission condition,
It is difficult to apply it to fuel cells and electrolytic capacitors.
Also, palladium is very expensive, which makes it practically difficult to use it industrially.

[0011] A gas containing hydrogen to be supplied to a fuel cell (eg,
As a method for removing carbon monoxide from a gas obtained by steam reforming a hydrocarbon), a method has been proposed in which only carbon monoxide is selectively oxidized on a catalyst. JP-A-11-1304
No. 06 proposes a method for removing carbon monoxide by reacting a reformed gas with oxygen on a catalyst in which a platinum group metal is supported on zeolite. JP-A-10-2471
No. 54 proposes a method using a catalyst in which rhodium or ruthenium is supported on zeolite, silica, or alumina. However, in these methods, the apparatus for mounting the selective oxidation catalyst tower and its heating unit is large and complicated. Further, when excessive steam is used during reforming, steam is mixed into the reformed gas, which lowers the catalytic activity and cannot remove the excess steam.

[0012] In the field of electrolytic capacitors,
JP-A-11212314 or JP-A-62-2725.
No. 15, a method of discharging hydrogen gas generated in an electrolytic capacitor to the outside using a hollow fiber-shaped permeable membrane made of polyimide, polytetrafluoroethylene, polypropylene, or the like is proposed. The effect of sufficiently discharging hydrogen gas to prevent the internal pressure from rising is not sufficient. Furthermore, in the electrolytic capacitor, since the electrolytic solution permeates as vapor from the electrolytic capacitor, the composition of the internal electrolytic solution changes, so that there is a great disadvantage that the characteristics of the electrolytic capacitor change.

Further, in recent years, membranes using zeolites have been actively studied, but it is difficult to obtain a zeolite membrane having specific transmission characteristics with good reproducibility. (1) 25
A membrane whose hydrogen permeation rate at 10 ° C. is 10 × 10 ⁻⁷ mol / (m ² / s / Pa) or more, and (2) a zeolite membrane that permeates hydrogen well but does not easily transmit water vapor and / or ethylene glycol Has not been proposed so far.

[0014]

It is an object of the present invention to overcome the disadvantages of the prior art described above, which is substantially free of expensive metals such as palladium which has an affinity for hydrogen, An object of the present invention is to provide a membrane which is excellent in heat resistance and chemical resistance, transmits hydrogen well, and (1) hardly transmits water vapor than hydrogen, and (2) hardly transmits ethylene glycol vapor.

[0015] Another object of the present invention relates to the application of the permeable membrane and related technologies, and relates to a fuel cell system having the permeable membrane, which effectively utilizes the permeability of the permeable membrane, and steam of hydrocarbon. An object of the present invention is to provide a reformer and an aluminum electrolytic capacitor.

[0016]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present invention has the following structure.

According to the first aspect of the present invention, the temperature of 65 ° C.
Ratio of hydrogen permeation rate V _H2 (mol / (m ² · s · Pa)) to water vapor permeation rate V _H2O (mol / (m ² · s · Pa)) V _H2 / V _H2O is 20 or more and 85 V _H2 (mol / (m
²・ s ・ Pa)) and ethylene glycol vapor permeation rate V _EG (m
ol / (m ² · s · Pa)), which is a permeable membrane not containing palladium as a main component, wherein V _H2 / V _EG is 50 or more.

The invention according to claim 2 of the present invention provides:
The permeable membrane satisfies the following characteristics (1) and (2).

(1) Hydrogen permeation rate at 25 ° C. is 10 × 1
0 ^-7 (mol / (m ² · s · Pa)) or more.

(2) A test tube containing ethylene glycol was sealed with the membrane, placed in an oven at 85 ° C., and the rate of weight loss was measured. The value was 6 × 10 6 per cm ^{2 of} membrane.
^-3 (g / hour) or less.

The present invention also includes the use of boehmite or pseudo-boehmite as an alumina source, and / or a method for producing a zeolite membrane in which a membrane having a silica source and an alumina source is treated with steam.

Further, the present invention provides a fuel cell system having the above-described permeable membrane or zeolite membrane, a steam reforming apparatus having the above-described permeable membrane or zeolite membrane, and an electrolytic capacitor having the above-described permeable membrane or zeolite membrane. included.

The present invention also includes a method of reforming a hydrocarbon with steam and then contacting the reformed gas with the above-mentioned permeable membrane or zeolite membrane to selectively permeate hydrogen from the reformed gas over steam. It is.

The invention according to claim 14 of the present invention relates to a method for separating gas or liquid using the above-described permeable membrane or zeolite membrane.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

First, the permeable membrane of the present invention will be described.

The permeable membrane of the present invention has a hydrogen permeation rate V _H2 (mol / (m ² · s · Pa)) at 65 ° C. and a water vapor permeation rate V
^{_{H2O (mol / (m 2 ·}} s · Pa)) of the ratio V _H2 / V _H2O is 20 or more,
And the hydrogen permeation rate V _H2 at ^{85 ℃ (mol / (m 2} · s · Pa))
And ethylene glycol vapor transmission rate V _EG (mol / (m ²
Pa)), wherein the ratio _VH2 / _VEG is 50 or more. A dense membrane such as a palladium membrane is known as a membrane through which hydrogen can selectively pass.However, a membrane which does not contain palladium as a main component and which permeates hydrogen with a higher selectivity than water vapor or ethylene glycol has been known. Not been.

The present invention also relates to a permeable membrane satisfying the following characteristics (1) and (2).

(1) Hydrogen permeation rate at 25 ° C. is 10 × 1
0 ^-7 (mol / (m ² · s · Pa)) or more.

(2) A test tube containing ethylene glycol was sealed with the membrane, placed in an oven at 85 ° C., and the rate of weight loss was measured. The value was 6 × 10 6 per cm ^{2 of} membrane.
^-3 (g / hour) or less.

A membrane which exhibits such a high hydrogen permeation rate at room temperature but is difficult to permeate ethylene glycol has not been known so far.

The permeable membrane referred to here may be made of a material having hydrogen permeation selectivity as a whole. However, usually, in order to increase the permeation rate, water vapor is deposited on a porous support having macropores. And / or a method of supporting a membrane that selectively permeates hydrogen over ethylene glycol is preferably used. A membrane that selectively permeates hydrogen from water vapor and / or ethylene glycol supported on a macroporous support in this manner is called a functional layer (or functional membrane). In order to show the permeability of the membrane of the invention described in claim 2, the thickness of the functional layer is preferably thin. The preferred thickness of the functional layer depends on the material of the functional layer to be selected.
m or less, more preferably 100 μm or less. The thinner the functional layer is, the more preferable it is. However, the functional layer should not be too thin to lose the denseness. Density does not mean non-porous, but means that there are no pinholes or holes due to defects.

The porous support used in the present invention is thin and is used for preventing a portion of the functional layer having low strength or brittleness from being broken, and the porous support is rigid. Is preferred.

In the case of a porous support that simplifies, it may not be possible to protect the functional layer from destruction.
Further, a film having such a strength that the porous support itself can be easily touched and broken by hand is not suitable for industrial practical use.

Further, since the present invention relates to a permeable membrane, the support for supporting the functional layer needs to have such a porosity as not to impair the permeability of the functional layer.

The material of the porous support is not particularly limited as long as it has the above properties, but examples thereof include metals, ceramics such as metal oxides, and organic polymers. From the viewpoint of strength and rigidity, ceramics such as metals and metal oxides are preferably used. Among them, metal oxides are most preferably used from the viewpoint of heat resistance and chemical resistance. The metal oxide is not particularly limited, but alumina, zirconia, silica, mullite, cordierite, titania, zeolite, or a zeolite analog is preferably used. Examples of the metal include a porous support made of stainless steel (sintered metal). In applications where heat resistance is not required, the organic polymer porous support can be used as long as it is rigid. Also in this case, in order to prevent destruction of the functional layer portion, it is preferable that the material has such rigidity that it does not bend visually when it is bent by hand.

The shape of the porous support is not particularly limited. For example, a commercially available shape such as a sphere, a plate, a tube, a monolith, and a honeycomb can be used. When used for an electrolytic capacitor, the porous support is preferably a cylindrical flat plate. When used as a separation membrane, the porous support needs to have a high surface area, and is preferably in the shape of a tube, a monolith, or a honeycomb.

The method for producing the porous support used in the present invention is not particularly limited. However, usually, a powder such as ceramics is used as it is, or an auxiliary or binder for molding is added to powder such as ceramics and extruded. Molding or press molding is performed, and a manufacturing method can be adopted through processes such as drying and baking.

The optimum firing temperature varies depending on the material of the porous support, but a temperature at which sintering starts a little is desirable from the viewpoint of strength. Suitable firing temperature varies depending on the material and the size of the particles, but is generally 600 ° C to 2,000 ° C.
Preferably 800 to 1500 ° C., particularly preferably 90 ° C.
0 to 1,400 ° C. After firing, treatment such as cleaning with a chemical solution may be performed. In addition, the formed porous support is coated with fine particles by a method such as dip coating to control the pore diameter of the porous support, control the affinity with the functional layer, or reduce the surface roughness. Control is also preferably performed. Such a layer formed by coating or the like is referred to as an intermediate layer. Providing one or more intermediate layers is preferably performed when any functional layer is used.

If the pore size of the porous support is too large, the functional layer will not be formed into a membrane and holes will be formed, or the raw material liquid for the functional layer will penetrate too much into the pores of the porous support, resulting in the final In addition, the hole of the porous support may be closed by the functional layer, that is, the distance that gas permeates the functional layer may be too long, and a sufficient gas permeation amount may not be obtained. Therefore, the average pore diameter of the porous support is 1
It is preferably 0 μm or less, more preferably 5 μm or less, further preferably 1 μm or less, and particularly preferably less than 0.5 μm. The above-mentioned intermediate layer is preferably used also in the sense of controlling the pore diameter. Although the lower limit of the average pore diameter cannot be specified depending on the size of the molecule to be permeated,
From the viewpoint of the permeability of the desired molecule, it is preferable that the average pore diameter is 0.01 μm or more.

The average pore size of the porous support can be usually measured using a mercury porosimeter. For simplicity, as long as the size of the ceramic particles constituting the intermediate layer is uniform, there is no significant difference even if the size of the particles is referred to as the average pore diameter.

In the permeable membrane of the present invention, the functional layer may be formed on any part of the porous support. The functional layer is
It can be formed on one or both surfaces of the porous support, on the inside, or on both the surface and the inside. When forming a functional layer, in terms of controlling the thickness of the functional layer,
It is preferable to coat the surface of the porous support, and it is preferable to form the coating inside the porous support in terms of the strength of the functional layer. In the case of a tubular porous support, it may be coated on the inside or on the outside. In the case of a monolithic or honeycomb-shaped porous support, the functional layer may be provided anywhere. However, in these cases, coating on the inner side is preferable because the surface area can be increased.

Measurement of hydrogen permeation rate referred to in the present invention
The method is described below. For example, 1cm ^TwoOn one side of the permeable membrane
Supply 2 atm of hydrogen gas and permeate from the other side of the membrane
Measure the amount of gas produced by a soap film flow meter. Use this method
And the permeation rate when 1 cc of hydrogen gas per second permeates
Is 4.5 × 10^-6(Mol / (m^Two・ S ・ Pa)).

The range of the hydrogen permeation rate measured by the above method will be described. Even if the hydrogen permeation rate of the permeable membrane is too small,
Problems arise if they are too large. Hydrogen permeation rate is 1 × 10 ^-7
If it is smaller than (mol / (m ² · s · Pa)), for example, when applied to a fuel cell described later, an enormous membrane area is required to transmit the amount of hydrogen gas generated from the reformer. Not suitable for practical use. Therefore, the permeation rate of hydrogen is 1 ×
It must be 10 ^-7 (mol / (m ² · s · Pa)) or more.
× 10 ^-7 (mol / (m ² · s · Pa)) or more is more preferable. Further, for example, when applied to an electrolytic capacitor described later, if the hydrogen permeation rate is smaller than 1 × 10 ⁻¹⁰ (mol / (m ² · s · Pa)), the amount of hydrogen gas generated inside the electrolytic capacitor becomes It is larger than the amount discharged to the outside of the electrolytic capacitor through the permeable membrane, and as a result, the hydrogen pressure inside the electrolytic capacitor increases, and the electrolytic capacitor is destroyed. Therefore, the permeation rate of hydrogen is 1 × 10 ⁻¹⁰ (mol / (m ² · s · P
a)) must be at least 1 × 10 ⁻⁹ (mol / (m ² · s · P
a)) The above is more preferred.

The upper limit of the transmission speed is not particularly limited, but is preferably smaller than 1 × 10 ⁻⁵ (mol / (m ² · s · Pa)). This means that the transmission rate is 1 × 10 ^-5 (mol / (m ²
This is because if it is larger than Pa)), not only hydrogen but also other components are well permeated, so that selectivity may be lost as a result.

The permeable membrane of the present invention desirably has not only a hydrogen permeation rate of at least a certain value but also a ratio of hydrogen permeation rate to water vapor permeation rate of at least a certain value. The method for measuring the water vapor transmission rate is as follows. The test tube filled with water is sealed with the permeable membrane and placed in a dryer at 65 ° C. to measure the rate of weight loss. Water vapor pressure at 65 ° C is 2.5 × 10 ⁴ P
a, Assuming that the steam concentration in the dryer is 0 Pa, the steam pressure difference is 2.5 × 10 ⁴ Pa. The water vapor transmission rate is derived from the permeation time, membrane area, and weight loss, and the unit is (mol / (m ² · s · Pa))
And This value is calculated based on the water vapor transmission rate: V _H2O (mol / (m ² · s · P
a)). The membrane of the present invention has a ratio V _H2 / V _H2O of 2 between the value and the hydrogen permeation rate at 65 ° _{C.:V H2} (mol / (m ² · s · Pa)).
It is preferably 0 or more. This value is preferably as large as possible, and more preferably 30 or more.

Further, in the permeable membrane of the present invention, it is desirable that the ratio of the hydrogen transmission rate to the ethylene glycol transmission rate is not less than a certain value. The method for measuring the ethylene glycol permeation rate is as follows. The test tube containing ethylene glycol was sealed with the permeable membrane, placed in an 85 ° C. oven,
The rate of weight loss is measured. Assuming that the vapor pressure of ethylene glycol at 85 ° C. is 1.05 × 10 ³ Pa and the ethylene glycol concentration in the dryer is 0 Pa, the ethylene glycol pressure difference is 1.05 × 10 ³ Pa. The ethylene glycol permeation rate is derived from the permeation time, membrane area, and weight loss, and the unit is (mol / (m
² · s · Pa)). This value is defined as ethylene glycol permeation rate: V _EG (mol / (m ² · s · Pa)). The membrane of the present invention has a value and hydrogen permeation rate at 85 ° C .: V _H2 (mol / (m ² · s · Pa))
The ratio V _{H 2} / V _EG and it is preferably 50 or more.
This value is preferably as large as possible, and more preferably 100 or more.

Further, assuming that the notation unit of the weight loss of ethylene glycol is g / cm ² · h, the weight loss rate at 85 ° C. is 6 × 1
0 is preferably less ^-3 g / cm ² · h. This value is preferably as small as possible, and more preferably 5.5 × 10 ⁻³ g / cm ² · h or less.

The heat resistance of the permeable membrane according to the present invention is not particularly limited. However, the following heat treatments (1) to (3) in air are performed according to (1) to (3). It is preferable to have heat resistance such that the hydrogen permeation rate after performing once in the order and the hydrogen permeation rate after performing twice in the order of (1) to (3) do not change by 10% or more.

(1) The temperature was raised from room temperature to 550 ° C. at 0.6 ° C./min.

(2) Hold at 550 ° C. for 4 hours.

(3) The temperature is lowered from 550 ° C. to room temperature at 1.2 ° C./min.

By performing the above treatment once, it is possible to remove the components which are attached to the surface or inside of the film and reduce the transmission speed. The hydrogen permeation rate after the treatment needs to be a value showing a sufficient permeation amount when used for the purpose of permeating hydrogen, and is 1 × 10 ⁻¹⁰ (mol / (m ² · s · Pa)). It is preferably at least 1 × 10 ⁻⁹ (mol / (m ² · s · Pa)). Further, the heat treatment in air from (1) to (3) was performed once in the order of (1) to (3), and the hydrogen permeation rate was performed twice in the order of (1) to (3). The fact that the subsequent hydrogen permeation rate does not change by 10% or more means that the membrane of the present invention has such heat resistance that the permeation performance does not change by the heat treatment. The hydrogen permeation rate after the twice treatment also needs to be a value showing a sufficient permeation amount when used for the purpose of permeating hydrogen.
^-10 (mol / (m ² · s · Pa)) or more, preferably 1 ×
10 ^-9 (mol / (m ² · s · Pa)) or more is more preferable.

The material of the permeable membrane used in the present invention is not limited, but preferably contains at least one of the following components (1) to (5).

(1) Zeolite (2) Fine particles of inorganic oxide (3) Silicone rubber, silicone resin or silicone oil (4) Organic polymer compound (5) Carbon The zeolite described in (1) above has a molecular size It is a crystalline inorganic oxide having a pore diameter. What is molecular size?
It is the size range of the molecule that exists in the world, and generally means the range of about 0.2 to 2 nm. The zeolite is a crystalline microporous substance composed of crystalline silicate, crystalline aluminosilicate, crystalline metallosilicate, crystalline aluminophosphate, crystalline metalloaluminophosphate, or the like.

The types of crystalline silicate, crystalline aluminosilicate, crystalline metallosilicate, crystalline aluminophosphate, and crystalline metalloaluminophosphate are not particularly limited. For example, atlas of zeolite structural types (Mayer, Olson,
Baerochar, Zeolites, 17 (1/2), 199
6) (Atlas of Zeolite Structure types (WM Meie
r, DH Olson, Ch. Baerlocher, Zeolites, 17 (1/2),
1996)).

As for the type of zeolite, it is preferable that the pore diameter of the crystal has a small one.
m and 0.2 nm or more are particularly preferable. More preferably, it is 0.6 nm to 0.2 nm. In the zeolite, the expression of the pore size is often referred to as an oxygen n-membered ring. In the present invention, a 5- to 12-membered zeolite is preferably used. Particularly preferred is a zeolite having 10 or less ring members. As a specific example of such a zeolite, Atlas of Zeolite Structural Types (Meyer, Olson, Baerochar, Zeolites, 17 (1/2), 1996) (Atlas of Zeolite S)
tructure types (WM Meier, DH Olson, Ch. Baerl
ocher, Zeolites, 17 (1/2), 1996)), in terms of their three-letter structure,
ABW, AEI, AFG, AFT, AFX, ANA, APC, ATN, ATO, ATT, ATV, AWW, BI
K, BRE, CAN, CAS, CHA, CHI, DAC, DDR, DOH, EAB, EDI, ERI, EUO,
FER, GIS, GOO, JBW, ZK-5, LAU, LEV, LIO, LOS, LOV, LTA, LTN, M
EL, MEP, MER, MFI, MFS, MON, MTN, MTT, NON, PAU, RHO, RON, RS
N, RTE, RTH, RUT, SGT, THO, TON, VET, VNI, VSV, WEI, WEN, YUG,
Zeolite having a ZON structure is exemplified. Although the zeolite structure is not particularly limited, the MFI type structure is preferably used in the present invention.

The composition of the zeolite is not particularly limited, but preferably contains a large amount of silica. Generally, zeolite is
Molecules can be separated by size differences, as called molecular sieves. The minimum molecular size of each of hydrogen, water, carbon monoxide, and carbon dioxide (Kinetic Diameter) is 0.29,
0.26, 0.38, and 0.33 nm (Break's Zeolite Molecular Sieves (1974, John Wiley & Sons Publishing Co., pp. 636-637)). From
It is very difficult to selectively permeate only hydrogen. The present invention has an important significance in that such difficult permeation of only hydrogen is realized. Although the mechanism of such selective permeation of hydrogen alone has not yet been elucidated,
There are pores sized to transmit hydrogen and the surface of the membrane and / or
Alternatively, it is considered necessary that the pores have hydrophobic properties to repel water. From such a viewpoint, it is preferable to use high silica or pure silica as the zeolite. Thus, zeolites are crystalline silicates, crystalline aluminosilicates, crystalline metallosilicate zeolites or zeolitic analogs, especially those of high silica, which are preferred because the pores are considered to be hydrophobic. For example, as a method of expressing the concentration of the silica component in the crystalline aluminosilicate, an SiO ₂ / Al ₂ O ₃ ratio is used. The larger this value is, the more hydrophobic the zeolite is. The range of SiO ₂ / Al ₂ O ₃ is not particularly limited, but in the present invention, those having 30 or more are preferably used.

With respect to silica, the abundance of heteroatoms other than silicon and oxygen is generally referred to as high silica when the molar ratio of silicon / heteroatoms is 5 or more, but is preferably 10 or more in the present invention. It is preferably at least 30 and particularly preferably at least 50. The larger the number, the better.

The pure silica is a zeolite substantially composed of only silica. Atlas of zeolite structure types (Meyer, Olson,
Baerochar, Zeolites, 17 (1/2), 199
6): Atlas of Zeolite Structure types (WM Meie
r, DH Olson, Ch. Baerlocher, Zeolites, 17 (1/2),
Zeolites published in (1996), they can be described by three-letter structure: ANA, BIK, BRE, CAN, CAS, CHA, CHI,
DAC, DDR, DOH, EAB, EDI, ERI, EUO, FER, GIS, JBW, KFI, LAU, LE
V, LTA, MEL, MEP, MER, MFI, MFS, MON, MTN, MTT, NON, PAU, RHO,
RON, RTE, RTH, RUT, SGT, THO, TON, VET, WEI, and YUG structures. Among them, DDR, DOH, EUO, FER, LEV, MEL, MEP, MFI, MFS, MTN, MT
Zeolite having a T, NON, RTE, RTH, RUT, or TON structure may be used. The most preferred structure is the MFI structure. The reason is that crystallization is easy and a film is easily formed.

However, the zeolite of the present invention is not limited to this example. Zeolites newly discovered after the publication of the above references, for example, CFI (CI
T-5) and the like are also included in the zeolite of the present invention. Of course, even if the zeolite itself is not of high silica or pure silica, it is sufficient that the portion in contact with the supply gas has hydrophobicity,
For example, zeolite whose surface has been subjected to a hydrophobic treatment can be used. The method of the hydrophobic treatment is not particularly limited, but any generally known method can be used. Examples thereof include treatment with a silicone compound such as silicone rubber or a silane coupling agent such as alkylalkoxysilane or alkylchlorinated silane, or treatment with a fluorine-based water repellent. The method of treatment is not particularly limited. For example, the treatment is performed by immersing or contacting or applying the zeolite membrane to a silicone-based coating agent solution dispersed or dissolved in a solvent such as water. Above all, a permeable membrane whose outermost layer is a functional layer made of zeolite coated with a silicone compound is particularly preferably used in the present invention.

When the functional layer is zeolite, since the surface of the zeolite crystal has a large number of OH groups, for example, a hydrophilic liquid such as water, ethylene glycol, or γ-butyrolactone contacts the functional film surface. In this case, a liquid film may be formed on the surface, and gas transmission may not occur for a while. However, if the outermost surface is thinly treated with a silicone compound, even if the hydrophilic liquid as described above comes into contact, it becomes a droplet, does not adhere as a liquid film, and the influence on gas permeability is reduced. This is an advantage of applying a silicone compound to the outermost surface.

The (2) inorganic oxide fine particles, (3) silicone rubber, silicone resin or silicone oil, (4) organic polymer compound and (5) carbon used as other materials in the present invention will be described in detail later. Explained.

The method for coating the zeolite on the porous support is not particularly limited. In general, the zeolite-containing membrane is directly coated on the porous support or the porous support provided with an intermediate layer, or is coated with an organic or organic material. And / or coating by being contained in a film of an inorganic polymer. Hereinafter, the porous support includes a porous support provided with an intermediate layer.

The method for producing the permeable membrane containing zeolite is not particularly limited, but a generally known method can be applied. For example, when a support is coated with a zeolite membrane on a support, a method of subjecting the support to a precursor gel for synthesizing zeolite and subjecting the support to hydrothermal treatment (eg, JP-A-63-291809) ), A method in which a support is coated in advance with a zeolite seed crystal and then the precursor gel is subjected to hydrothermal treatment (eg, JP-A-7-109116).
A method in which a precursor gel is coated on the surface of a support, dried and then treated with steam (steam method) (eg, JP-A-7-89714), or a method of coating zeolite fine particles as they are (Japanese Patent Publication No. No. 5-50331) can be applied. A membrane formed by a method in which the precursor gel is coated on the surface of the support, dried, and then treated with steam is excellent in hydrogen permselectivity and is preferably used. This method has the advantage that less waste liquid is required because only the required amount of precursor is coated on the support.

The zeolite precursor is a mixture that can be converted into a zeolite by heating for a certain period of time, and contains a silica source, an alkali source, an organic template, water and the like. An alumina source and the like are included as necessary. Here, essential ones are a silica source and water, and others depend on the type of zeolite to be made.

As a silica source, colloidal silica, fumed silica, water glass, precipitated silica, silicon alkoxide and the like are used. The alkali source is an alkali metal hydroxide such as sodium hydroxide, lithium hydroxide, potassium hydroxide, or the like.

The organic template is a template for an organic compound that constructs the pores of zeolite, and includes a template such as tetraethylammonium hydroxide, tetrapropylammonium hydroxide, or tetrabutylammonium hydroxide.
Grade ammonium salts, crown ethers, alcohols and the like are used.

An alumina source is required when making a crystalline aluminosilicate zeolite. For example, hydrated alumina such as boehmite, pseudo-boehmite, or an aluminum salt such as aluminum nitrate, aluminum sulfate, or aluminum chloride, or aluminum hydroxide, aluminum oxide, or aluminum alkoxide can be used. The aluminum source used in the present invention is not particularly limited, but boehmite and pseudo-boehmite are preferably used. Here, the boehmite is alumina hydroxide represented by AlO (OH). This is obtained by subjecting aluminum hydroxide (Al (OH) ₃ ) to hot water treatment at 150 to 375C. Depending on the steam treatment temperature and the steam concentration during the hot water treatment, alumina hydroxide having another structure is mixed. They are called pseudo-boehmite.
As commercial products, Pural and the like from Condea are known.

The method for coating the support with the zeolite seed crystal and the zeolite precursor is not particularly limited.
Any known method can be applied. For example, a dip coating method in which the support is dipped in the slurry and then pulled up as it is, a method of applying with a brush or a blade, a method in which one side of the support is brought into contact with the slurry and the pressure is reduced from the other side, How to apply pressure and push in,
A spin coating method in which the coating solution is dropped while rotating the support, and a spray coating method in which the coating solution is sprayed onto the support to coat the coating solution are conceivable.

It is preferable that the seed crystal be present in the pores of the porous support in view of the strength, pressure resistance and denseness of the membrane. However, the seed crystal may be attached to the surface of the support. Absent.

Whether the zeolite membrane was formed was determined by determining whether the thin film X
It can be measured by the line diffraction method. Specifically, for example, X
X-ray diffraction can be measured with a parallel optical system using CuKα as the radiation source (wavelength = 0.154 nm), the incident angle fixed at 3 °, and the scan speed at 2θ 4 ° / min. It can be identified by comparing the obtained X-ray diffraction pattern with the X-ray diffraction pattern of a known document. In addition, the orientation of the zeolite membrane can be considered by comparing the peak intensity ratio of each peak.

As described above, the zeolite membrane is coated on the porous support, but the zeolite membrane may be coated twice or more. Further, it is preferable to perform the measurement twice or more in terms of denseness.

After the zeolite membrane has been formed, treatments such as washing with water, drying and firing may be added. Whether or not a zeolite membrane has been formed can be confirmed using an X-ray diffractometer for a thin film. When firing the generated zeolite membrane, the temperature is raised as long as possible in order to prevent the generated zeolite membrane from cracking. Preferably, the heating rate is 3
C./min or lower, more preferably 2.degree. C./min or lower, particularly preferably 1.degree. C./min or lower. Of course, it is better that the temperature drop rate is low. Preferably, the temperature is lowered at a rate of 5 ° C./min or less, more preferably 3 ° C./min or less, particularly preferably 2 ° C./min or less. The firing temperature is generally about 150 to 600 ° C.

When the permeable membrane containing zeolite is formed into a composite membrane of an inorganic and / or organic polymer, the zeolite is prepared in advance by a hydrothermal synthesis method or a steam method, and the particles are mixed with the polymer. I do. The method is not limited to this, but any method can be used as long as a polymer mixed with zeolite is formed. After the zeolite membrane is formed, a polymer may be coated. The type of polymer to be mixed is
Although not particularly limited, examples thereof include silicone rubber, polysulfone-based polymer, and phenol resin.

It is preferable that the zeolite-containing permeable membrane has as few holes as possible except for the holes in the zeolite crystal.
Reducing such holes outside the crystal is referred to as densification treatment. It is preferable that such holes outside the crystal (gap between crystals) be as small as possible. Therefore, it is preferable to perform the densification treatment on the permeable membrane. Of course, if a dense film is formed without performing the densification processing, it is not necessary to perform the densification processing. As a method of the densification treatment, a known method can be used, but as a specific example, it does not enter pores of zeolite, but enters other pores, for example, pores formed at a grain boundary between crystals. A method of impregnating with an organic material having a desired size, followed by baking in a gas substantially free of oxygen such as nitrogen gas, and carbonizing to fill the pores, is not limited to this method. Further, it is also possible to fill holes outside the crystal or to form a composite film with carbon by heating with a phenol resin or the like which is easily carbonized and then heating. A polymer compound such as silicone may be buried in the pores formed at the grain boundaries, or may be a composite film with these. The monomer may be introduced into the grain boundary and polymerized there.

The zeolite may have an ion exchange point, but the cation exchanged at the ion exchange point is not particularly limited. For example, H ⁺ , Li ⁺ , Na ⁺ , K ⁺ , R
b ⁺ , Cs ⁺ , Ca ²⁺ , Mg ²⁺ , Ba ²⁺ , Ag ⁺ , C
Any cation such as u ²⁺ , Cu ⁺ , Ni ²⁺ , La ³⁺ can be exchanged, and any cation can be at the ion exchange point.

The functional layer in the present invention may be an aggregate of only inorganic oxide fine particles. This is a permeable membrane that, unlike zeolite, actively utilizes the fine pores in the gap between the fine particles. The smaller the size of the fine particles, the smaller the pore size of the permeable membrane, which is preferable for permeation selectivity. In the present invention, it is preferable that the functional layer formed of the inorganic oxide has micropores (2 nm or less). The method for forming the functional layer using the inorganic oxide fine particles is not particularly limited, but a method in which a colloid or a slurry in which the inorganic oxide fine particles are dispersed is applied and immersed in a porous support, or a method in which a chemical vapor deposition method is applied to the porous support. For attaching oxide fine particles. The porous support, the densification treatment, and the hydrophobization treatment are the same as those described above for the zeolite functional layer. Complexing with other functional layers such as zeolite, silicone compounds, organic polymers, and carbon is also preferably performed.

[0079] Silicone rubber and / or silicone resin and / or silicone oil can also be used as a material for the functional layer of the permeable membrane of the present invention. Particularly, those containing silicone rubber are preferably used. Silicone in the present invention refers to an organosilicon polymer compound having a siloxane bond as a skeleton and an organic group or the like bonded to the silicon atom. Silicone rubber is a material made of silicone, which is formed by bridging a high degree of polymerization linear polyorganosiloxane to a medium extent to exhibit rubber-like elasticity, and is also called a silicone elastomer. Silicone rubber is superior to organic resins in heat resistance and chemical resistance.
It can also be used for high-temperature applications. Silicone rubbers are classified by various methods according to their properties. From the viewpoint of vulcanization temperature, silicone rubbers can be classified into heat vulcanization type, low temperature vulcanization type and room temperature curing type.

The heat-curable silicone rubber is a type of silicone which requires heating at a temperature higher than the decomposition temperature of the peroxide vulcanizing agent at the time of vulcanization, whereby rubber elasticity can be obtained for the first time. The raw material of the heat-vulcanized silicone rubber is mainly solid and is called millable rubber (kneadable rubber), but is not always solid.

On the other hand, the low-temperature-curable silicone rubber is in the form of a liquid or paste, has a long pot life at room temperature after the addition of the curing agent, and is excellent in workability. In addition, it does not require as high a temperature as the heat-curable silicone rubber at the time of curing, and cures rapidly by heating from 100 to 150 ° C.

On the other hand, room temperature curing type silicone rubber is a silicone rubber which literally undergoes a curing reaction at room temperature to become a rubber elastic body. The room-temperature-curable silicone rubber is also in a liquid or paste state before being cured. The difference between these curing temperatures depends on the degree of polymerization of the polyorganosiloxane in the raw material and the types and amounts of additives, fillers and crosslinking agents. The type of the silicone rubber used in the present invention is not particularly limited, but a low-temperature vulcanization type silicone rubber and a room temperature curing type silicone rubber are preferably used from the viewpoint of good workability.

The silicone rubber includes a silicone resin (silicone resin) which is generally called. Silicone resin is a hard material having a much higher crosslink density than the above three types of silicone rubber. Silicone resins are broadly classified into straight silicone resins and silicone-modified organic resins. The straight silicone resin is composed of only silicone, and the silicone-modified organic resin is a copolymer of a silicone component and an organic resin. A silicone resin may be used depending on the required amount of transmission.

The curing mechanism of silicone rubber is roughly classified into a condensation reaction type and an addition reaction type. In the condensation reaction type,
The condensation reaction occurs due to the moisture in the air, and the curing proceeds.
On the other hand, the addition reaction type is mainly a hydrosilylation (hydrosilylation) reaction and does not generate by-products.

Such a silicone compound, when formed into a film, transmits hydrogen and the like better than other polymer films, but has a higher hydrogen permeability than the aforementioned porous films such as zeolite film and oxide fine particle film. Speed is low. The reason is considered that the silicone film and the organic polymer film described later transmit molecules by dissolving and diffusing into the polymer, and the resistance during the permeation of the molecules is considered to be higher than that of the porous film. Therefore, in order to obtain a desired transmission amount, it is preferable that the functional layer is thin. However, care must be taken because if the thickness is too small, the selectivity may be reduced. The thickness of the film is not particularly limited, but is preferably 0.1 to 500 μm. The preferred film thickness varies depending on the application, but for electrolytic capacitors, it is preferably about 0.1 to 200 μm. Preferably 0.5 to
It is 150 μm, particularly preferably 1 to 100 μm. Such a thin film alone does not have practical strength. Therefore, in the present invention, the porous support is coated with these functional layers. The form and use method of the support are as described above.

The components of the silicone rubber raw material solution are not particularly limited. For example, the following components can be used. First of all, all silicone rubbers use polyorganosiloxane (silicone polymer) as the main raw material, reinforcing fillers such as dry silica and wet silica, fillers such as diatomaceous earth and quartz powder, various additives, and crosslinking agents as organic solvents. Is preferably applied. The organic solvent used here is not particularly limited as long as it can dissolve or highly disperse the above raw materials, but toluene, xylene,
n-Heptane, ligroin, isopropyl alcohol and mixtures of these organic solvents are preferably used. The molecular structure of the polyorganosiloxane is not particularly limited, but those in which a methyl group, a phenyl group, a vinyl group, or a trifluoropropyl group is bonded to silicon are preferably used. Also, the degree of polymerization of the raw material polymer is not particularly limited, but those having a molecular weight of 10,000 or less are preferably used because of the simplicity of the coating operation.

The method of coating the support with the silicone rubber is not particularly limited, but for example, the following method can be used. After preparing the silicone rubber raw material solution, apply it on a support, or immerse the support in the silicone rubber raw material solution, or contact the silicone rubber raw material solution with one surface of the support, Is applied from the surface opposite to the surface to be coated. After carrying the silicone rubber solution on the support using any of these methods, a treatment may be performed to cure the silicone rubber. As an example of the treatment method, a method in which the mixture is left at room temperature in the air for 10 minutes to 1 week or heated to 200 ° C. or lower and left for 10 minutes to 1 week is preferably used.

An organic polymer or carbonized carbon is also effective as a functional layer. As the organic polymer, polyimide, Teflon, butylene rubber, isobutylene rubber, or polypropylene, phenol resin is preferably used, and as carbon, polyimide or polyphenol is baked in vacuum, in a nitrogen stream, in an inert gas, or in the air. What has been carbonized is preferably used. The organic polymer film is a non-porous film like the above-mentioned silicone film, and has a lower hydrogen permeability than the porous film. It is preferably 100 μm or less, more preferably 10 μm or less. As a method of coating the organic polymer on the porous support, the polymer is melted or dissolved in a solvent, and applied.
A method such as dipping or spraying is used, but is not limited thereto. Carbon can be obtained by coating an organic polymer or an organic substance which is easily carbonized in advance, and then baking in vacuum, in a nitrogen stream, in an inert gas, or in the atmosphere. Among carbons, a porous carbon molecular sieve having pores of a molecular size is particularly preferable.
Examples of carbonized carbon sieves that are carbonized include polyimide and phenolic resin, but are not limited thereto. The organic polymer or carbon functional layer may be used alone, but is preferably used in combination with another functional layer.

The present invention also relates to a fuel cell system equipped with the above permeable membrane or zeolite membrane.

The fuel cell system expected as a next-generation power generation system has four types of solid polymer type, phosphoric acid type, solid oxide type and molten carbonate type depending on the ion exchange membrane used.
Are classified into two types. Among these, the solid polymer type and the phosphoric acid type supply hydrogen to the fuel of the fuel cell and use a proton conductive membrane as the ion exchange membrane. As a method for supplying hydrogen,
There are a method of directly supplying hydrogen and a method of reforming from hydrocarbon. The hydrocarbon used is not particularly limited as long as hydrogen gas is efficiently generated in the reforming reaction.
Aliphatic hydrocarbons and alcohols are preferably used. In consideration of environmental issues, hydrocarbons that generate a high H ₂ / CO ₂ ratio are preferable, and methanol and methane are particularly preferable. Gasoline is also one of the preferred hydrocarbons because of the infrastructure for supplying fuel.

As the reforming method, a generally known reforming method is applied. For example, steam reforming for supplying steam and oxidation reforming for supplying oxygen or air are preferably used. Since steam reforming is an endothermic reaction and oxidative reforming is an exothermic reaction,
Each needs to be heated or radiated. Therefore, an autothermal method of supplying steam and oxygen or steam and air at a predetermined ratio so as to eliminate the need for heating or heat radiation is also preferably used.

When steam is used for reforming hydrocarbons, the following reaction occurs in the reformer.

[0093]

(Equation 3)

Further, a small amount of carbon monoxide is mixed into the reformed gas by the following shift reaction.

[0095]

(Equation 4)

As described above, in addition to hydrogen and carbon dioxide, carbon monoxide generated by the shift reaction, and water vapor and hydrocarbon as raw materials are mixed in the reformed gas.

In particular, when steam is excessively added in order to sufficiently perform the reforming reaction, the steam concentration in the reformed gas becomes high. When a reformed gas having a high water vapor concentration is used, there are problems that the activity of the carbon monoxide oxidizing catalyst is deteriorated and that the fuel electrode of the fuel cell is covered with water vapor to lower the power generation efficiency. In addition, when the water vapor concentration is high, the hydrogen concentration decreases accordingly, and the power generation efficiency decreases. On the other hand, when the membrane of the present invention is used, hydrogen can be selectively permeated from steam from the reformed gas, so that the deterioration of the activity of the carbon monoxide oxidation catalyst can be suppressed, the decrease in the hydrogen concentration is suppressed, and Water coating on the fuel electrode can be suppressed.

It is known that carbon monoxide produced by a hydrocarbon reforming reaction poisons a catalyst on a fuel electrode. Therefore, it is preferable to use a membrane that selectively transmits hydrogen than carbon monoxide because hydrogen gas having a low carbon monoxide concentration can be supplied to the fuel electrode without using a carbon monoxide oxidation catalyst. Since there is no need to install a carbon monoxide oxidation catalyst,
It is also preferable in that the device can be simplified. For selectively transmitting hydrogen over carbon monoxide, for example, a surface-treated zeolite membrane is effective. A method of performing separation using hydrogen and carbon monoxide by using a zeolite membrane having a reduced pore diameter by performing a silane treatment is preferably used. Also in this case, if the membrane does not selectively transmit hydrogen than water, water coexisting in the reformed gas is adsorbed in the pores of the membrane, and the amount of permeated hydrogen decreases. Therefore, a membrane that selectively permeates hydrogen over water is also extremely important in separating hydrogen / carbon monoxide gas in the presence of water vapor.

The present invention also relates to a steam reforming apparatus equipped with the above permeable membrane or zeolite membrane.

In the case of reforming hydrocarbons by steam, a mixture of hydrocarbons and steam is supplied to a reforming catalyst at 300 to 800 ° C. When the reaction shown in the equation (1) proceeds to some extent and the hydrogen concentration in the gas increases, the probability of contact between hydrocarbon and water decreases, and the reforming reaction rate decreases significantly. Further, according to the formula (2), undesirable carbon monoxide is generated.
Therefore, as shown in FIG. 1, a part or all of the wall of the catalytic reaction tower is made of the membrane of the present invention, and the generated hydrogen gas is selectively removed from the outside of the tower with respect to water or methanol, thereby controlling the equilibrium. Since the reaction proceeds efficiently without being performed, the reforming reaction rate can be improved. As a result, not only can hydrogen be produced efficiently, but also the concentration of carbon monoxide can be reduced. Further, the gas that has passed through the membrane has a higher hydrogen concentration and a lower water vapor concentration than the reformed gas generated by a normal reforming reaction. When this gas is supplied to, for example, a fuel electrode portion of a fuel cell, the electrode is not covered with water vapor and high power is obtained.

The present invention also relates to an electrolytic capacitor equipped with the above permeable membrane or zeolite membrane.

The electrolytic capacitor according to the present invention will be described in detail.

The permeable membrane of the present invention is applied to an electrolytic capacitor having an anode foil and a cathode foil superposed in a container, an anode terminal and a cathode terminal having one end protruding outside the container, and an electrolytic solution. If used, the permeable membrane permeates the hydrogen gas generated inside the capacitor and does not allow the electrolyte to permeate as liquid or vapor, so that the internal pressure does not increase and the composition of the electrolyte does not change significantly. It is very effective in terms of life, stability and performance.

Although the electrolytic capacitor of the present invention is not particularly limited, it has a particularly excellent effect when the electrolytic solution is a liquid capacitor. In particular, the present invention is particularly effective for aluminum electrolytic capacitors, especially for large screw terminal type aluminum electrolytic capacitors.

Hereinafter, the electrolytic capacitor of the present invention will be described with reference to the drawings. FIG. 2 is a schematic cross-sectional view showing an example of an electrolytic capacitor using the permeable membrane of the present invention.
FIG. 3 is a schematic plan view of a sealing plug portion of the electrolytic capacitor in FIG. 2 as viewed from above.

That is, in FIG. 2, the electrolytic capacitor element wound with kraft paper interposed between the anode foil and the cathode foil is impregnated with the electrolytic solution, and the anode terminal and the cathode terminal are projected from the through hole of the sealing plug. , In a container made of aluminum. FIG. 3 is a view showing the sealing plug of FIG. 2 as viewed from above. The permeable membrane of the present invention can be installed at the position shown in FIG. 3 with an adhesive or the like, for example.

Since the permeable membrane of the present invention is permeable to hydrogen but not permeable to water, water, ethylene glycol and γ-butyrolactone, which are the main components of water vapor and the electrolytic solution, are difficult to transmit, and the composition of the electrolytic solution is changed. In addition, since hydrogen generated by the electrolysis can be released to the outside, the rupture of the capacitor can be avoided, and the performance can be stabilized for a long time.

As the form of the permeable membrane used in the present invention, a flat permeable membrane is preferably used. The shape of the permeable membrane is not particularly limited, and the size may be smaller than the size of the sealing plug, but is preferably smaller than the radius of the sealing plug.
The thickness of the permeable membrane is not particularly limited, as long as it has a mechanical strength that does not break during setting.

The film of the present invention is not limited to the use described above.

For example, after reforming a hydrocarbon with steam,
The present invention includes all methods for contacting the above-mentioned membrane with the membrane to selectively permeate hydrogen from reformed gas over water vapor.

Further, the present invention includes all separation methods using the above-mentioned membrane.

For example, a gas permeates in the presence of polar molecules such as water, ammonia, and ethylene glycol,
There are many uses such as separation, and a membrane having not only the ability to permeate gas but also the above-mentioned property of not permeating polar molecules can be used for various uses. For example, it can be widely used for separation of nitrogen and oxygen from air containing water vapor, purification of hydrogen from hydrogen gas containing water vapor, degassing of a dissolved gas in a polar solvent such as water, and the like.

The present invention will be described in more detail with reference to the following examples. However, the following examples are given for illustrative purposes and should not be construed as limiting in any sense.

[0114]

EXAMPLES (Example 1) [Synthesis of seed crystal for silicalite membrane synthesis] 20 g of a 20 to 25% aqueous solution of tetrapropylammonium hydroxide (TPAOH) (manufactured by Tokyo Chemical Industry Co., Ltd.)
-25% aqueous solution), 0.28 g of sodium hydroxide (Katayama Chemical Co., Ltd., first grade) was added and stirred. Further, 5 g of fumed silica (Aldrich) was added and heated to 80 ° C. to obtain a transparent aqueous solution. Put this in the polytetrafluoroethylene line autoclave,
After heating at 25 ° C. for 8 hours, silicalite fine particles (average particle size: about 80 nm) were obtained. Water was added to this to form a silicalite colloid containing 1 wt% silicalite.

Example 2 [Coating of Seed Crystal on Porous Support] 0.1 g of the silicalite colloid of 1% by weight obtained in Example 1 was mixed with α of a square having a side of 1.4 cm and a thickness of 3 mm. -Porous alumina support (ceramic film (1
(00mmX100mmX3mm) cut to this size: coated on one side only with alumina fine particles for a thickness of about 50 μm, average pore diameter is 0.1 μm). After drying, the resultant was dried and calcined at 550 ° C. for 3 hours to obtain a seed crystal-coated support.

(Example 3) [ZSM-5 by steam method]
Production and Evaluation of Membrane] On the surface of the porous support coated with the seed crystal obtained in Example 2 coated with silicalite particles (functional layer precursor), 40 SiO ₂ : 0.8 Al ₂ O ₃ : 0.1 g of a gel having a composition of 12 TPAOH (tetrapropylammonium hydroxide): 430H ₂ O was dropped, and dried overnight at room temperature to obtain a sample film. The SiO ₂ source Ludox HS-40 (Du P
ont), and Pural (CONDEA) as the Al ₂ O ₃ source.
Was used. As shown in FIG. 6, in a 50 ml autoclave, put 0.5 g of water, place the sample membrane on a polytetrafluoroethylene table, place it in the autoclave,
Heating was performed at 150 ° C. for 5 days under the self-control of steam (hereinafter, this operation is referred to as steam treatment). After washing with water and drying, ZS
That the thin film of M-5 is formed on the porous support,
Confirmed by X-ray diffraction and electron microscope. Next, the film sample was fired at 550 ° C. for 2 hours. The rate of temperature rise during firing was 0.6 ° C./min., And the rate of temperature drop was 1.2 ° C./min. X
As a result of line diffraction and electron microscopic observation, it was confirmed that a thin film of ZSM-5 (silica / alumina ratio: 50) was formed on the porous support even after firing.

Example 4 [Creation of Transmission Measurement Cell] The present apparatus will be described with reference to FIG. This device is made of stainless steel and supplies gas from a gas supply port. The permeable membrane is
It is fixed via silicone rubber which is an elastic body,
The surface of the permeable membrane having the functional layer faces the gas side shown in the gas supply port. In order to prevent gas from leaking from the gap between the silicone rubber and the permeable membrane, the surface of the permeable membrane opposite to the surface having the functional layer is pressed by a stainless steel fitting. In addition, since this metal fitting is fixed with an O-ring, the gas that has passed through the permeable membrane does not leak from a portion other than the permeable gas outlet.

(Example 5) [Measurement of hydrogen permeation rate using cell for permeation measurement] Using the apparatus shown in Example 4, the hydrogen gas permeation rate of the film produced in Example 3 was measured. The transmission device was placed under an atmosphere of 20 ° C., where supply of hydrogen 2 atm to the gas supply side of the apparatus, the amount of hydrogen gas that has passed through the membrane was measured with soap film flow meter, 15.0 × 10 ^-7 (mol / (m ² · s · Pa)).
Next, the transmission device is set in an oven, and the oven is set to 65 ° C.
Heated. Hydrogen at 2 atm was supplied to the gas supply side of the apparatus, and the hydrogen gas permeated through the membrane was sent to a soap film flow meter in a 20 ° C atmosphere through a stainless steel pipe, and the flow rate was measured to be 13.8 × 10 ^-7. (Mol / (m ² · s · Pa)). Next, the mixture was heated to 85 ° C. in an oven, hydrogen at 2 atm was supplied to the gas supply side of the apparatus, and hydrogen gas permeated through the membrane was sent to a soap film flow meter under a 20 ° C. atmosphere through a stainless steel pipe. When the flow rate was measured, 13.6 × 10
^-7 (mol / (m ² · s · Pa)).

Next, the film produced and fired in Example 3 was reused.
The temperature is raised from room temperature to 550 ° C. at 0.6 (° C./min),
Hold at 550 ° C. for 4 hours, from 550 ° C. to room temperature 1.2
(° C./min). Hydrogen permeation rate by the above method at room temperature
Measured 15.5 × 10 ^-7(Mol / (m^Two・ S ・ Pa))
Was. The transmission speed after firing twice is the same as the transmission speed after firing once.
About 3.3%.

Example 6 [Hydrogen / Steam Permeation Rate Ratio] Water was placed in a test tube and its weight was measured. Separately, the zeolite membrane shown in Example 3 was fixed to the permeation device shown in Example 4. The gas supply port of the permeation apparatus and the port of the test tube were connected by a rubber tube. The entire apparatus was kept at 65 ° C., and saturated steam at 65 ° C. was exposed to the membrane. The device was removed from the oven every few hours, allowed to cool at room temperature, and the test tubes and water weighed. From the heating time and the weight loss of water, the average rate of weight loss of water was derived. As a result, 4.8
× 10 ⁻³ g / h · cm ² . The water vapor transmission rate was 0.38 × 10 ⁻⁷ (mol / (m ² · s · Pa)), and the ratio V _H2 / V _{H2O to} the hydrogen transmission rate at 65 ° C. was 36.

(Example 7) [Hydrogen / ethylene glycol permeation rate ratio] Ethylene glycol was placed in a test tube, and its weight was measured. Separately, the zeolite membrane shown in Example 3 was fixed to the permeation device shown in Example 4. The gas supply port of the permeation apparatus and the port of the test tube were connected by a rubber tube. The entire apparatus was kept at 85 ° C., and the membrane was exposed to saturated ethylene glycol vapor at 65 ° C. The device was removed from the oven every few hours, allowed to cool at room temperature, and the test tubes and ethylene glycol were weighed. The average rate of weight loss of ethylene glycol was derived from the heating time and the weight loss of ethylene glycol. As a result, it was 4.9 × 10 ⁻⁴ g / h · cm ² . This ethylene glycol permeation rate is 2.1 × 10 ^-8
(Mol / (m ² · s · Pa)), and the ratio V _H2 / V _{EG to} the hydrogen permeation rate at 85 ° C. was 65.

(Example 8) [Preparation of electrolytic capacitor] 0.1 g of the silicalite colloid of 1 wt% obtained in Example 1 was coated with a porous cylindrical support of α-alumina having a diameter of 9 mm and a thickness of 2 mm ( Nippon Insulator Co., Ltd. processed: Alumina fine particles coated on one side only to a thickness of about 50 μm, average pore diameter is 0.1 μm). Drop on the surface treated with alumina fine particles as uniformly as possible. After coating, the coating was dried and baked at 550 ° C. for 3 hours to obtain pellets coated with seed crystals. This is Ludox HS-30
It was immersed in a mixture of 1 g, 0.01 g of Pural, 1 g of a 20% aqueous solution of TPAOH and 2.48 g of water, pulled up, left at room temperature for 1 hour, and then heated at 150 ° C. for 5 days under steam pressure.
After washing with water, the film sample was fired at 550 ° C. for 2 hours. The heating rate during firing was 0.6 ° C / min., And the cooling rate was 1.2 ° C / min.
min. It was confirmed by X-ray diffraction and an electron microscope that a silicalite thin film was formed on the support.

As shown in FIG. 5, a spring was applied to the non-processed surface of the pellet, which was sandwiched and fixed between the upper and lower portions of the sealing plug. Using this sealing plug, a large screw terminal type electrolytic capacitor as shown in FIG. 2 was produced.

(Example 9) [Production of steam reforming apparatus] Alumina tube (material: α-alumina, inner diameter: 7 m)
m, outer diameter: 10 mm, length: 300 mm, α-alumina particles having a particle diameter of 0.1 μm coated on the inner wall with a thickness of 50 μm), and the 1 wt% silicalite seed crystal solution prepared in Example 1 was added to the inner wall. After applying 12 g / cm2, 500
Fired at ℃. Close one end of the alumina tube, and open the zeolite precursor sol (Ludox HS-30 1g, P
ural, a mixture of 1 g of a 20% aqueous solution of TPAOH and 2.48 g of water) and allowed to stand for 2 minutes. Thereafter, the liquid in the tube was discarded, the alumina tube was dried at room temperature, and then heated at 150 ° C. for 5 days under steam pressure. After washing with water, the cylindrical film sample was fired at 550 ° C. for 2 hours. The heating rate during firing was 0.6 ° C./min, and the cooling rate was 1.2 ° C./min. ZS
The fact that a thin film of M-5 is formed on the inner wall of the tube is indicated by X
Confirmed by line diffraction and electron microscope. The 16 tubular membranes were bundled into a bundle as shown in FIG. 6 to produce a zeolite membrane module. This was filled with a copper-zinc methanol reforming catalyst as shown in FIG. 1 to produce a steam reforming apparatus.

Example 10 [Fabrication of Fuel Cell System] A fuel cell system will be described with reference to FIG. The steam reforming apparatus shown in Example 9 was used, and a pipeline was connected so that the gas permeating the permeable membrane forming the wall of the steam reforming apparatus and the gas discharged from the outlet of the apparatus could be mixed. An air supply was connected to this pipeline.
This pipeline was connected to a carbon monoxide selective oxidation catalyst device. A pipeline was connected so that the gas discharged from the catalyst device could be supplied to the fuel electrode of the fuel cell, and a fuel cell system was produced.

(Comparative Example 1) [Production and evaluation of silicalite membrane by steam method] The silicalite particles (functional layer precursor) of the porous support coated with the seed crystal obtained in Example 2 were coated. On the surface, 0.1 g of a gel having a composition of 40 SiO ₂ : 12 TPAOH (tetrapropyl ammonium hydroxide): 430 H ₂ O was dropped and dried overnight at room temperature to obtain a sample film. Si
Ludox HS-40 (manufactured by DuPont) was used as the O2 source. This was steamed. After washing with water and drying, it was confirmed by X-ray diffraction and an electron microscope that a thin film of silicalite was formed on the porous support. Next, the film sample was fired at 550 ° C. for 2 hours. The rate of temperature rise during firing was 0.6 ° C./min., And the rate of temperature drop was 1.2 ° C./min. As a result of X-ray diffraction and electron microscopic observation, it was confirmed that a silicalite thin film was formed on the porous support even after firing.

The transmission characteristics were evaluated according to the methods of Examples 5, 6, and 7. The permeation rate of hydrogen is 3.2 × 10 ^-7 (mol /
(m ² · s · Pa)), hydrogen selectivity is V _H2 / V _H2O 6.3, V _H2
/ V _{E G} was 12.8.

[0128]

The present invention relates to a membrane which selectively permeates hydrogen from water vapor or ethylene glycol. The permeable membrane is suitably used for gas separation or permeation under a condition in which a highly polar compound vapor such as water, ethylene glycol, γ-butyrolactone, and ammonia exists. The membrane can of course be used as a membrane for various gas permeation or a membrane for liquid permeation in the absence of a highly polar compound vapor.

The present invention also relates to the application of the transparent film and related techniques. The permeable membrane of the present invention can be used for applications such as fuel cells and electrolytic capacitors. A fuel cell uses hydrogen as a fuel, and the hydrogen is obtained by directly receiving the supply of hydrogen or by reforming a hydrocarbon such as methanol, methane or gasoline with steam or the like. The method of reforming hydrocarbons is advantageous in that the fuel storage unit can be reduced in weight and that infrastructure maintenance is relatively easy. The gas generated when the stretcher hydrogen is steam reformed contains water, carbon monoxide, and carbon dioxide in addition to hydrogen. If the water vapor concentration in the reformed gas is high, there are disadvantages that the activity of the carbon monoxide reforming catalyst is reduced, the hydrogen concentration is reduced, and the fuel electrode is covered to lower the power generation efficiency. On the other hand, when the membrane of the present invention is used during or after the steam reforming reaction, hydrogen can be selectively permeated from the reformed gas, so that the reforming reaction can be made more efficient and hydrogen can be efficiently extracted. Can be.

When the permeable membrane of the present invention is used for an electrolytic capacitor, the life of a conventionally known electrolytic capacitor, which has been damaged by the pressure of hydrogen gas generated inside a sealed container, can be sufficiently extended, and the electrolytic capacitor can be used. Safety during use of the capacitor can also be ensured.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of a steam reformer using a permeable membrane of the present invention.

FIG. 2 is a schematic cross-sectional view showing one example of an electrolytic capacitor using the permeable membrane of the present invention.

FIG. 3 is a schematic plan view of a sealing plug portion of the electrolytic capacitor in FIG. 2 as viewed from above.

FIG. 4 is a schematic side view for explaining a cell for measuring transmission performance of a permeable membrane of the present invention.

FIG. 5 is a view showing how to attach a zeolite membrane to a sealing plate in FIG. 3; (The zeolite membrane is attached to the sealing plate via silicone rubber which is an elastic body.)

FIG. 6 is a diagram showing a tubular zeolite membrane of the present invention that is modularized into a bundle.

FIG. 7 is a schematic diagram of a fuel cell system using the permeable membrane of the present invention.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) H01M 8/04 H01M 8/04 GF term (reference) 4D006 GA41 HA21 HA41 JA02A JA02B JA02C JA03A JA03C JA07C MA02 MA03 MA04 MA09 MA10 MA22 MB02 MB04 MB06 MC01 MC03 MC03X MC05 MC09 MC30X MC65 MC68 NA21 NA39 NA46 NA54 NA62 NA63 NA64 PA03 PB13 PB66 PC01 4G040 EA02 EA03 EA03 EA06 EB33 FA02 FC01 FD01 FE01 5H027 BA01 BA16

Claims (13)

[Claims] 1. Hydrogen permeation rate at 65 ° C. V _H2 (mol / (m
²・ s ・ Pa)) and water vapor transmission rate V _H2O (mol / (m ²・ s ・ P
a))) The ratio of V _H2 / V _H2O is 20 or more and the hydrogen permeation rate V _H2 (mol / (m ² · s · Pa)) at 85 ° C. and the ethylene glycol vapor permeation rate V _EG (mol / (m ²・ s ・ Pa)) ratio V _H2
/ _VEG is 50 or more, a permeable membrane not containing palladium as a main component. 2. A permeable membrane satisfying the following characteristics (1) and (2). (1) The hydrogen permeation rate at 25 ° C. is 10 × 10 ⁻⁷ (mol / (m
²・ s ・ Pa)) or more. (2) sealed to tubes containing ethylene glycol in the membrane, placed in a 85 ° C. oven, then the weight loss rate was measured and the value film 1 cm ² per 6 × 10 ^-3 (g / hour) or less That. 3. The hydrogen permeation rate after performing the heat treatment in air (1) to (3) shown below once in the order of (1) to (3), and (1) to (3). 3. The permeable membrane according to claim 1, wherein the hydrogen permeation rate after performing twice in the following order does not change by 10% or more. (1) The temperature was raised from room temperature to 550 ° C. at 0.6 (° C./min). (2) Hold at 550 ° C. for 4 hours. (3) The temperature is lowered from 550 ° C. to room temperature at 1.2 (° C./min). 4. The permeable membrane according to claim 1, comprising at least one of the following components (1) to (5). (1) zeolite (2) inorganic oxide fine particles (3) silicone rubber, silicone resin or silicone oil (4) organic polymer compound (5) carbon 5. Zeolite having an SiO ₂ / Al ₂ O ₃ content of 30.
The permeable membrane according to claim 4, characterized in that: 6. The permeable membrane according to claim 5, wherein the zeolite is an MFI-type zeolite. 7. A method for producing a zeolite membrane, wherein boehmite or pseudo-boehmite is used as an alumina source. 8. The method for producing a zeolite membrane according to claim 7, wherein the membrane having a silica source and an alumina source is treated with steam. 9. A fuel cell system equipped with the permeable membrane according to claim 1 or the zeolite membrane obtained by the method according to claim 7 or 8. 10. A hydrocarbon steam reforming apparatus equipped with the permeable membrane according to any one of claims 1 to 6 or the zeolite membrane obtained by the production method according to claim 7 or 8. 11. An aluminum electrolytic capacitor equipped with a permeable membrane according to claim 1 or a zeolite membrane obtained by the production method according to claim 7. 12. After the hydrocarbon is reformed with steam, the reformed gas is applied to the permeable membrane according to any one of claims 1 to 6 or the zeolite membrane obtained by the production method according to claim 7 or 8. A method in which hydrogen is allowed to permeate from the reformed gas more selectively than water vapor. 13. A method for separating gas or liquid using a permeable membrane according to any one of claims 1 to 6 or a zeolite membrane obtained by the production method according to claim 7.