JP2002219341A - Supporting base for hydrogen-permselective membrane and hydrogen-permselective member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a porous supporting base excellent in layability and durability as a hydrogen-permselective facility and to provide a high-separation- performance hydrogen-permselective member using the base. SOLUTION: There are disclosed a supporting base for a hydrogen- permselective membrane which is a base for supporting a hydrogen-permselective membrane and comprises a multilayer-structure metallic porous sintered body, wherein the relative density of the sintered body on the side of the hydrogen- permselective surface is at least 60% and has a mean particle diameter of at least 10 μm, whereas the sintered body on the side of the crude gas contact surface has a mean particle diameter of at most 8 μm, a maximum particle diameter of at most 45 μm, and an areal opening coverage of at least 30%, and a hydrogen-permselective member composed of the base and a hydrogen- permselective membrane formed thereon.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydrogen selective permeation material used for producing a hydrogen selective permeation member for selectively separating hydrogen from a crude gas containing hydrogen to obtain high-purity hydrogen gas. The present invention relates to a substrate for supporting a membrane and a hydrogen selective permeable member using the substrate.

[0002]

2. Description of the Related Art As an energy-saving gas separation technology,
In recent years, attention has been paid to a gas selective separation method using a membrane. In particular, as research on the practical application of fuel cells has recently progressed,
An important issue is how to efficiently produce high-purity hydrogen gas as a fuel.A typical method is to produce hydrogen by pyrolysis of hydrocarbon gas such as city gas or natural gas. And a method of obtaining high-purity hydrogen from the produced gas (crude gas). In this case, the crude gas obtained by pyrolysis contains a large amount of carbon monoxide, carbon dioxide gas, etc. in addition to hydrogen, so it is necessary to separate hydrogen from the crude gas containing them. As a separation method, a method using a hydrogen-permeable member having a hydrogen-permeable film such as Pd formed on the surface of a porous body is known.

[0003] In producing the hydrogen permeable member, the porous material used for supporting the hydrogen selective permeable membrane may be a porous metal or ceramic obtained by sintering a powder, a sintered product of a metal nonwoven fabric, or a foamed product. Metals and bulk materials in which fine holes are formed countlessly are used.

On the surface of these porous bodies, for example, sputtering, arc ion plating (hereinafter, referred to as
An AIP) method, a plating method, a thermal spraying method, a rolled foil laminating method, or the like is used to form a hydrogen-selective permeable film to obtain a hydrogen-selective permeable member.

By the way, the performance required of the hydrogen selective permeation member is not only that it can selectively permeate hydrogen efficiently, but also that the hydrogen permeation amount per unit area must be increased to enable industrial practical use. It is important to increase productivity.

Currently, the most widely used hydrogen selective permeable membranes are Pd-based metal films and alloy films having excellent oxidation resistance and hydrogen dissociation properties. Has a performance (membrane permeability, ie, productivity) of at most 20 cm ³ / min · cm ^{2. In} order to promote practical use on an industrial scale, the hydrogen gas permeation amount is 40 cm ³ / m.
There is a need for a technique that can secure in.cm ² or more and efficiently separate and separate high-purity hydrogen of 99.99% or more level efficiently. A hydrogen selective permeable membrane that can secure a hydrogen permeation amount is required. In order to put such a thin hydrogen selective permeable membrane into practical use, a supporting base material for supporting the membrane is required, but the performance as a hydrogen selective permeable member is significantly changed by the supporting base material. . In addition, the configuration of the supporting base material has a great effect on workability (such as weldability) when incorporated into an actual device as a hydrogen selective permeable member, and durability during continuous use. For this reason, some improvements have been made on the base material for supporting the hydrogen selective permeable membrane.

For example, Japanese Patent Application Laid-Open No. Sho 62-121616 discloses that a ceramic porous body having a two-layer structure is used as a supporting substrate, and only a surface layer (a rough gas contact surface side) is a fine-grained sintered body layer. Thus, a technique for increasing the density of a hydrogen selective permeable membrane formed on the surface has been proposed. However, when ceramics are used as the supporting base material, the following problems occur.

[0008] Since the bondability with the joint member is very poor, it is difficult to bond and maintain airtightness when incorporating into the hydrogen selective permeation apparatus. The pressure loss during the selective separation operation becomes high, and it is difficult to obtain satisfactory productivity. On the other hand, when the particle size of the porous body is set to several μm or more for the purpose of reducing the pressure loss, the strength and toughness of the supporting substrate are extremely reduced, and cracks and chips are easily caused.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a hydrogen permeable membrane made of a metal or alloy such as a Pd-based metal which is mainly used at present. And a hydrogen selective permeation amount of 40 cm ³ / min while ensuring hydrogen purity of 99.99% or more.
・ Provide a porous support base material that can obtain cm ² or more, and can also satisfy workability and durability as a hydrogen selective permeation facility, and provide high separation performance using the base material. An object of the present invention is to provide a hydrogen selective permeable member.

[0010]

Means for Solving the Problems The hydrogen selective permeable membrane supporting substrate according to the present invention, which can solve the above problems, comprises:
A base material for supporting the hydrogen selective permeable membrane, which is made of a metal porous sintered body having a multilayer structure, and the hydrogen selective permeable surface has a sintered body having a relative density of at least 60% and a sintered body. The average particle diameter of the particles is 10 μm or more, and the average particle diameter of the sintered body particles is 8 μm or less,
The point is that the opening area ratio is 5% or less and the opening area ratio is 30% or more.

Although various metals and alloys can be used as the material of the supporting substrate according to the present invention, stainless steel is generally considered in consideration of thermal stability, oxidation resistance, hydrogen dissociation, cost and the like. Is the most common. Further, in the support substrate of the present invention, if a diffusion prevention layer such as an oxide film or a ceramic layer is formed on the surface of the sintered body on the side of the crude gas contact surface, during the hydrogen selective permeation treatment, hydrogen selective This is preferable because it is possible to avoid the problem that the metal component (Fe or the like) constituting the supporting base material is diffused and mixed into the membrane such as Pd or an alloy thereof constituting the permeable membrane to deteriorate the hydrogen selective permeability.

[0012] The hydrogen selective permeable member according to the present invention includes:
The gist lies in that the hydrogen selective permeable membrane is formed on the crude gas contact surface side of the hydrogen selective permeable membrane supporting substrate having the above-described configuration. As the hydrogen selective permeable membrane used here, a hydrogen selective permeable metal film or alloy film, among which a thin film of Pd or an alloy thereof having a thickness of about 10 μm or less is preferable, and a method for forming such a metal or alloy film is preferable. Is to consider the film forming property and film performance comprehensively,
The vapor phase film forming method, in particular, the arc ion plating method is most suitable.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION A porous metal porous sintered body which satisfies the above requirements, for example, a Pd-based metal or alloy is provided on the crude gas contact surface which is dense and has a high opening area ratio. By forming a hydrogen selective permeable membrane made of, for example, hydrogen gas having excellent hydrogen selective permeability and high purity of 99.99% level or more, for example, 40 cm ³ / mi,
It is possible to obtain a hydrogen selective separation device capable of separating and recovering under high productivity such as n · cm ² or more. In addition, since the support base is made of a sintered metal material, it can be easily and firmly joined to a joint member or the like by, for example, laser welding, electron beam welding, or friction welding. The workability as a selective separation facility can be enhanced, and the durability of the facility can be enhanced.

Hereinafter, the reasons for determining the above requirements will be described in detail.

First, as the material of the porous sintered body, a metal material is used in consideration of environmental resistance such as oxidation resistance, bondability at the time of equipment construction, durability at the time of equipment operation, and the like. The type of metal is not particularly limited, and non-ferrous metals such as titanium, nickel, and aluminum and alloys thereof can be used. However, heat resistance, oxidation resistance, structural strength, cost, etc. are comprehensively considered. Most preferred is an iron-based metal, with stainless steel being most preferred.

Conventionally, as described above, the main focus has been on suppressing the reaction between the Pd-based hydrogen selectively permeable membrane and the porous body, and porous ceramics such as alumina have been used as a support base material. It is pointed out that workability in assembling the apparatus is extremely poor due to extremely difficult joining and the like, and satisfactory durability is hardly obtained due to insufficient joining strength. However, in the present invention,
Since a metal sintered body is used as the support base material, not only weldability is good and workability when assembling the equipment is good, but also the durability of the equipment is improved, and the reliability of the whole equipment during continuous use is improved. Can be enhanced.

However, since this supporting base material is made of a porous sintered body even though it is made of metal, it can be joined by, for example, TIG welding or MI.
When a normal welding method such as G welding is used, cracks and the like tend to be easily generated in a welded portion and its surroundings. Therefore, it is preferable to use laser welding, electron beam welding, or friction welding as a joining method. . Even when such a welding joining method is employed, if the relative density of the porous metal sintered body is low, cracks are likely to occur at the joint and its surroundings due to volume shrinkage during welding. In order to prevent this and to assure safe and reliable joining, it is essential to ensure that the relative density of the metal porous sintered body is 60% or more.

The supporting substrate according to the present invention is a porous sintered body having a multilayer structure, typically a two-layer structure, as described above, and a crude gas contact surface on which a hydrogen permeable film is formed. It is not always necessary to make the relative density 60% or more on the side, and the relative density on the side of the hydrogen selective permeable surface, which is relatively thick and is the main part of the welding joint, is made 60% or more, thereby ensuring excellent jointability. can do. However, if the relative density is too high, the pressure loss increases and the amount of hydrogen permeation decreases, so it is preferable to suppress the pressure loss to preferably 90% or less, more preferably 85% or less.

On the other hand, the hole diameter of the porous sintered body as the supporting base material is preferably as large as possible in order to reduce the pressure loss during the hydrogen selective permeation treatment. In order to more reliably form a thin and hydrogen-permeable membrane, the size of the hole is desirably as small as possible. Therefore, the present inventors have further studied on the requirements for realizing the formation of a dense film excellent in hydrogen selective permeability with a film thickness of about 10 μm or less, and as a result, the formation surface side of the hydrogen selective permeable film, that is, The average particle size of the sintered metal particles on the crude gas contact side is 8 μm or less, and the maximum particle size is 45 μm.
I figured out what to do next.

If the average particle diameter of the sintered particles on the hydrogen selective permeable membrane forming surface side exceeds 8 μm, the number of coarse holes formed on the surface of the sintered body increases, and the surface is formed on the surface. It becomes difficult for the hydrogen permselective membrane to be dense, and when there is a coarse particle having a maximum particle size of more than 45 μm as the sintered particles, a large hole is formed in the periphery thereof, and the dense hydrogen permselective membrane is also formed. It becomes difficult to form. Therefore, on the side of the supporting base material on which the hydrogen selective permeable membrane is formed, that is, on the side of the crude gas contact surface, the average particle size of the sintered body particles on the surface is set at 8 to enable the formation of a dense hydrogen selective permeable membrane.
μm or less, more preferably 6 μm or less, and the maximum particle size must be suppressed to 45 μm or less, more preferably 30 μm or less. However, if the average particle size of the sintered particles is too small, the hydrogen permeation amount tends to decrease. Therefore, the average particle size is preferably 3 μm or more, more preferably 4 μm or more.

As a method for forming the hydrogen selective permeable film, a sputtering method, an arc ion plating method, a vapor deposition method, a plating method, a thermal spraying method and the like can be adopted. The most preferred film forming method for easy and reliable formation is the arc ion plating method.

As described above, in the support substrate of the present invention, the average particle size of the sintered particles on the hydrogen selective permeable membrane forming surface side is 8 μm or less, more preferably 6 μm or less, and the maximum particle size is 45 μm or less. However, if the average particle size of the entire porous sintered body as a supporting base material is set to 8 μm or less, the pressure loss as a supporting layer can be easily reduced. Becomes very large,
The amount of hydrogen permeation is drastically reduced, and the purpose of improving productivity cannot be fulfilled.

If the supporting base material is made thinner, the pressure loss can be reduced. However, in such a case, the strength of the thin film supporting structure becomes insufficient and the weldability is adversely affected. Is desirably at least about 1 mm or more. Therefore, in the present invention, a requirement for securing a sufficient hydrogen permeation amount (about 40 cm ³ / min · cm ² or more) by minimizing pressure loss while securing the reinforcing effect and weldability as a thin film supporting structure. As for the surface of the metal porous sintered body on the crude gas contact side where the hydrogen selective permeable membrane is formed, the average particle diameter of the sintered body particles is 8 μm or less and the maximum particle diameter is 45 μm or less. The sintered body particles on the hydrogen selective permeable surface side as the main body have an average particle diameter of 10 μm or more (preferably 15 μm or more, and a preferable upper limit for securing the structural strength as a support layer is about 30 μm or less),
In addition, the relative density is specified to be 60% or more in consideration of the joining property.

Also, no matter how the pressure drop of the supporting substrate is reduced and the thickness of the hydrogen selective permeable membrane is reduced, the opening of the surface of the sintered body constituting the supporting substrate where the hydrogen selective permeable membrane is formed is formed. If the area ratio is small, the effective hydrogen selective permeable surface of the hydrogen selective permeable membrane is closed by the non-opening surface of the supporting base material surface, and a sufficient amount of hydrogen cannot be obtained. Therefore,
In order to suppress such an obstacle and secure a sufficient amount of hydrogen permeation, the opening area ratio of the hydrogen selective permeable membrane forming surface of the supporting base material, that is, the surface of the crude gas contact side is 30% or more, preferably 35% or more.
% Should be secured.

FIG. 1 is a cross-sectional enlarged explanatory view illustrating a supporting base material according to the present invention and a hydrogen selective permeable member having a hydrogen selective permeable film formed on the surface thereof. Is shown.

That is, the supporting base material shown in the figure is composed of a sintered body layer (layer B) constituting the crude gas contact surface side and a sintered body layer (layer A) constituting the hydrogen selective permeable surface side. You.

The layer A has a sintered particle diameter of 1 as described above.
Since it is made of a sintered body of 0 μm or more and has relatively large voids between particles, it has a small airflow resistance and becomes a layer mainly composed of a support having a small pressure loss. Further, the relative density of the layer A is set to be higher than 60% so that the welding can be easily and reliably performed. The relative density is more preferably 65% or more, but if the relative density is too high, the pressure loss increases and the amount of hydrogen permeation decreases, so 90% or less, more preferably 85% or less.
% Or less.

On the other hand, the layer B constitutes the hydrogen selective permeable film forming side as described above, and has an average particle diameter of the sintered body particles so that a dense and defect-free hydrogen selective permeable film can be formed more reliably and easily. When it is 8 μm or less, the maximum particle size is suppressed to 45 μm or less, and in order to secure a sufficient hydrogen permeation amount, the opening area ratio is set to 30% or more, more preferably 35% or more.

In the supporting substrate made of the sintered body having the two-layer structure, the layer A serves as a main layer for securing the structural strength of the supporting substrate and improving the weldability. Preferably, the thickness is about 0.5 mm or more, more preferably about 0.7 mm or more.
The upper limit of the thickness of the A layer is not particularly limited, but the structural strength and weldability can be sufficiently secured at a thickness of about 1 mm,
Thicker than that just adds weight,
Since it is economically disadvantageous, it is desirable to suppress the thickness to about 1.5 mm or less, more preferably to about 1.2 mm or less. On the other hand, the layer B is a layer for enabling the formation of a dense and defect-free hydrogen selective permeable membrane. Since the effect of improving structural strength and weldability is not so required, the layer B is, for example, 5%.
Even a relatively thin wall having a thickness of about 0 μm or less can sufficiently fulfill the purpose. However, if the thickness is too large, it causes a decrease in the amount of hydrogen permeation due to an increase in airflow resistance. Therefore, the thickness is preferably suppressed to about 200 μm or less, more preferably 100 μm or less.

In the illustrated example, a two-layer structure composed of an A layer and a B layer is shown. However, in the present invention, the A layer side is composed of a layer mainly composed of a support having low airflow resistance and weldability, and the B layer side has an opening. Since it only needs to be composed of a dense layer with a large area ratio,
As long as these requirements are satisfied, it is of course possible to form one or two or more layers having an intermediate value between the A layer and the B layer having a ventilation resistance or a relative density between the two layers to form a multilayer structure. In this case, it is also possible to adopt an inclined structure in which the ventilation resistance and the relative density change continuously from the layer A side to the layer B side.

The hydrogen selective permeable member of the present invention is manufactured by forming a hydrogen selective permeable membrane C on the layer B side of the supporting substrate made of the sintered body having the multilayer structure.
As a constituent material of the hydrogen selective permeable membrane C, as described above, Pd
Or its alloys are the most common, but in addition to Ti,
Zr, V, Nb, Ta and alloys containing them can also be used.

If the hydrogen selective permeable membrane has a multi-layer structure and the procedure of polishing the surface after forming each layer and then forming the next layer is repeated, the polishing process fills the pinholes and removes macro particles. This is preferable because the density of the hydrogen selective permeable membrane as a whole can be further increased, and a thinner membrane having excellent hydrogen selective permeable ability can be formed.

Although the thickness of the hydrogen selective permeable membrane C is not particularly limited, it is preferably 1 μm or more to secure a sufficient amount of hydrogen permeation while securing the strength as the hydrogen permeable membrane.
μm or less, more preferably 5 μm or more and 8 μm or less. As a method for forming the hydrogen selective permeable membrane, a sputtering method, an arc ion plating method and the like are exemplified as preferable methods as described above.

In forming the hydrogen selective permeable membrane C on the surface of the layer B in the supporting base material, the metal component constituting the base material diffuses and moves in the direction of the permeable membrane C so that the hydrogen selective permeable performance is improved. Therefore, it is preferable to form the diffusion prevention layer D on the surface of the layer B and then form the hydrogen selective permeable film C. The function and specific configuration of the diffusion prevention layer D are described below. Details will be described later.

The shape and structure of the hydrogen selective permeable membrane supporting substrate and the hydrogen selective permeable member according to the present invention are not particularly limited, and may be cylindrical or flat depending on the shape and structure of the hydrogen selective permeable equipment. Although it can be designed in any shape such as a shape, a cylindrical shape is most common when applied to a hydrogen selective permeation device currently in practical use. In the case of a cylindrical structure, the formation side of the A and B layers should be set depending on whether the hydrogen gas is selectively permeated from the inside to the outside of the cylinder or from the outside to the inside. It is.

Next, a method of manufacturing a metal sintered body having a multilayer structure having the above-mentioned requirements is not particularly limited, but a general method is as follows.

First, the diameter of the sintered particles is substantially determined by the particle diameter of the metal particles used as a sintering raw material, and the relative density and opening area ratio of the sintered body are determined by the pressure at the time of compacting the metal particles. And sintering conditions (especially sintering temperature). Incidentally, when the metal particles are compacted and then sintered, the adjacent metal particles are only diffusion bonded at a part of the surface, and the size of the metal particles themselves hardly changes. On the other hand, as the molding pressure at the time of compacting is increased, the metal particles are densely packed, the relative density of the sintered body is increased, and the voids between the particles are reduced accordingly, so that the opening area ratio is reduced. On the other hand, as the particle diameter of the metal particles decreases, the number of contact points for sintering increases, so that the smaller the particle diameter of the metal particles, the higher the density tends to be. Further, the size of the interparticle voids becomes smaller as the particle diameter becomes smaller and the sintered body becomes denser, but the airflow resistance tends to become higher.

Therefore, as a preferred method for obtaining a sintered body having the above-mentioned required characteristics, the average particle diameter of the sintered material on the hydrogen selective permeable surface side is 10 μm.
m or more, more preferably about 15 μm or more, and preferably about 30 μm or less. If the powder is compacted to a density that can secure a relative density of about 60% or more, and then sintered, good. In addition, it is also possible to adjust a relative density by mixing a desired amount of a binder at the time of compacting.

The preferred compacting pressure and sintering temperature vary depending on the type of metal and the like, but the preferred compacting pressure when using the most common stainless steel powder is 50 MPa.
a to 300 MPa, more generally 100 MPa
a, 200 MPa or less, sintering temperature is 750 ° C. or more,
1000 ° C. or less, more generally 800 ° C. or more, 950
It is below ° C. The atmosphere during the compacting and sintering is preferably performed in a non-oxidizing atmosphere in order to prevent the metal powder from being oxidized and causing sintering failure.

On the crude gas contact surface side on which the hydrogen selective permeable membrane is formed, it is necessary to secure a dense surface having an appropriate opening area ratio as described above. More preferably, a metal powder having a size of 6 μm or less and a maximum particle size of 45 μm or less, more preferably 30 μm or less is used. As a pressure at the time of compacting, an appropriate porosity (and a surface opening area ratio) is secured. 50 to do
MPa or more, 200 MPa or less, more preferably 75M
Adopt Pa or more, 100 MPa or less, 750 ° C. or more,
900 ° C or lower, more preferably 800 ° C or higher, 850 ° C
It is desirable to sinter below. Also in this case, it is desired that the compacting and sintering be performed in a non-oxidizing atmosphere.

As a means for forming the sintered body into a two-layer structure, a method of compacting and sintering one layer and then compacting and sintering the other layer may be adopted. You can,
A preferred method is to first compact one layer, then compact the other layer, and then sinter them simultaneously. The means for forming a structure having three or more layers is not essentially different, and a method of sequentially compacting the first layer, the second layer, the third layer,... And simultaneously heating and sintering them. Is preferably employed.

The supporting substrate of the present invention thus obtained is formed as a hydrogen selective permeable member by forming a hydrogen selective permeable membrane on the dense sintered body surface side. In the case of a sintered body using a base alloy, if a hydrogen selective permeable membrane such as Pd is formed directly on the surface of the sintered body, for example, Fe constituting the sintered body during use diffuses in the direction of the hydrogen selective permeable membrane. There is a possibility that the alloying reaction occurs to cause an alloying reaction to deteriorate the hydrogen selective permeability of the permselective membrane, thereby impairing the durability as equipment.

Accordingly, in order to prevent such a diffusion of the sintered metal in the direction of the permselective membrane, prior to the formation of the hydrogen permselective membrane, a diffusion preventing layer is formed on the surface of the sintered body constituting the supporting base material. And it is desirable to prevent direct contact between the sintered body and the hydrogen selective permeable membrane. Examples of such a diffusion prevention layer include an oxide layer of the sintered metal itself or another ceramic layer. The former oxide layer can be formed by oxidizing the surface of the sintered body, and the latter ceramic layer can be formed by coating a ceramic material by any method such as a sputtering method or an ion plating method. I just need. The oxide layer formed when stainless steel is used as the sintered body is an oxide mainly composed of Cr, Fe, and Mn, and the Mn content in the oxide layer exceeds 40% by mass. And Mn
Since the oxide gradually decreases during use and the diffusion preventing action tends to decrease with time, the Mn content in the oxide layer is 40% by mass.
It is desirable to keep it below.

The ceramics constituting the other diffusion preventing layer may be any of oxides, nitrides, carbides, borides and the like, but they are easy to form and provide excellent barrier properties. Particularly preferred are chromium oxide, aluminum oxide, chromium nitride and the like. At this time, it is preferable to form an oxide film by oxidizing the surface of the sintered body and further form a ceramic layer thereon, since the diffusion preventing effect can be further enhanced.

A preferable thickness for effectively exhibiting the diffusion preventing effect of these diffusion preventing layers is about 0.1 μm or more, more preferably about 0.3 μm or more. However, if the diffusion preventing layer becomes too thick, Hydrogen permeation is impaired and causes a reduction in the amount of hydrogen permeation.
It is desirable to suppress the thickness to about μm or less, more preferably to about 1 μm or less. Further, the diffusion preventing layer is only for preventing the metal component in the sintered body from being diffused and transferred in the direction of the hydrogen selective permeable membrane. Therefore, microscopically, as shown in FIG. It is desirable that the particles are formed only on the surface layer side of the sintered body particles without closing the opening on the surface of the sintered body.

As described above, according to the present invention, when a hydrogen selective permeation facility is manufactured by effectively utilizing a hydrogen selective permeation membrane such as a Pd-based membrane having excellent oxidation resistance and hydrogen dissociation properties,
By using a multi-layer metal porous sintered body with specified density, particle size, open area ratio, etc. as its supporting substrate, it maintains excellent structural strength, weldability, durability, etc. On the other hand, it has become possible to provide a hydrogen selective permeable member that can obtain high-purity hydrogen of, for example, 99.99% level or more with a permeation amount of about 40 cm ³ / min · cm ² or more with high productivity.

In the above description, an example was described in which the most typical powder was used as the metal material constituting the porous sintered body as the supporting base material. In addition, it is also possible to use a nonwoven fabric of metal fibers or chopped strands. What is necessary is to control. If necessary, the relative density, airflow resistance, surface aperture ratio, and the like of the sintered body can be adjusted by appropriately using a metal powder and a metal fiber nonwoven fabric or chopped strand.

In the present invention, the average particle diameter, the maximum particle diameter, and the opening area ratio of the sintered body particles were determined by photographing the surface of the sintered body with an optical microscope at a magnification of 1000 times,
It was determined by observing 10 visual fields with a size of 5 mm x 95 mm. In each photograph, each sintered body particle was bordered. Each particle hardly undergoes grain growth, substantially maintains the shape and particle size of the particles used as the raw material, and is a porous body, so that each particle can be sufficiently distinguished. Based on the obtained photographs, the average particle size (Fulman method), the maximum particle size, and the opening area ratio were determined by the following methods. Average particle size (D) = (4 / π) × (NL / NS) NL: Number of particles hit by an arbitrary straight line on the photographic surface per unit length NS: Number of particles included in an arbitrary unit area The opening area ratio is = [(total area of photograph-area occupied by particles)
/ (Total area of the photograph)] × 100 The relative density was determined from the dimensions (volume) and weight of the sintered body assuming that the true density was 7.8 g / cm ³ .

[0049]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples, and the present invention is not limited thereto. The present invention can be modified and implemented, and all of them are included in the technical scope of the present invention.

EXAMPLE A pipe-shaped support substrate made of a porous metal sintered body having the following two-layer structure was prepared, and SUS was attached to both ends of the support substrate.
After laser welding the 410 cap (see Figure 2:
1 denotes a hydrogen selective permeation tube, 2 denotes a connection cap), a diffusion prevention layer is formed on the outer surface side, and P is formed by AIP method.
A d-based hydrogen selectively permeable membrane was formed (see FIG. 3: 3 is a supporting substrate, and 4 is a hydrogen selectively permeable membrane), and a hydrogen selective permeation experiment was performed. Table 1 shows the molding conditions and composition of the test materials and the test results.
It is shown in FIG. However, the durability was evaluated by the amount of decrease in the amount of hydrogen permeation for one hour after the elapse of 24 hours with respect to the amount of hydrogen permeation for the first hour in the hydrogen permeation experiment. , And 1% or more was evaluated as x. Supporting substrate: outer layer outer diameter; diameter 20.2 mm, outer layer inner diameter;
Diameter 20 mm, inner layer inner diameter: 18 mm, length 80 mm, joint processing: Laser welding of SUS410 caps to both ends of the support base material, formation of a diffusion prevention layer: support base material surface in air at 650 ° C. for 30 minutes Oxidation treatment or coating of ceramic material on the outer layer side by sputtering method, Formation of hydrogen selective permeable membrane: Pd-Ag on the surface of each supporting base material with a cap joined and a diffusion prevention layer formed on the outer surface side
A film was formed by the AIP method, and a hydrogen selective permeation test: 600 ° C. for 24 hours.

[0051]

[Table 1]

[0052]

[Table 2]

As is clear from Tables 1 and 2, in all of the examples satisfying the specified requirements of the present invention, the purity of permeated hydrogen is 99.99% or more and a high hydrogen permeation amount is obtained. Example 3 is an example in which the diffusion prevention layer was not formed between the base material and the hydrogen selective permeable membrane, and had a problem in durability. On the other hand, in Comparative Examples lacking any of the requirements of the present invention, the purity of permeated hydrogen does not reach the target level, the productivity cannot be satisfied due to the insufficient amount of hydrogen permeation, or the welding is poor and lacks practicality.

[0054]

According to the present invention, a porous metal sintered body having a multilayer structure is used as a substrate for supporting a hydrogen selective permeable membrane, and an average of the permeable membrane forming side is used. By specifying the particle size and the maximum particle size and the opening area ratio, by specifying the relative density and the average particle size on the opposite surface side,
In addition to eliminating the poor weldability and poor durability pointed out in the conventional ceramic support base material, the raw gas is used to remove 99.9% from crude gas.
It has become possible to provide a hydrogen selective permeable member that can obtain high-purity hydrogen of 9% level or more with a high hydrogen permeation amount and high productivity.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of an essential part illustrating a cross-sectional structure of a hydrogen selective permeable membrane supporting substrate and a hydrogen selective permeable member according to the present invention.

FIG. 2 is a schematic front view showing a supporting base material used in the experiment.

FIG. 3 is a schematic cross-sectional view of a hydrogen selective permeable member used in an experiment.

[Description of References] A Sintered body layer on the hydrogen selective permeable surface side B Sintered body layer on the crude gas contact surface side C Hydrogen selective permeable membrane D Diffusion prevention layer 1 Hydrogen selective permeable tube 2 Connection cap 3 Supporting substrate 4 Hydrogen Permselective membrane

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Toshiki Sato 1-5-5 Takatsukadai, Nishi-ku, Kobe City Inside Kobe Research Institute, Kobe Steel Ltd. (72) Inventor Tatsuya Yasunaga 1-chome, Takatsukadai, Nishi-ku, Kobe-shi No. 5-5 Kobe Steel, Ltd.Kobe Research Institute, Kobe Research Institute F-term (reference) CA17 FB02 FC02 4G140 FA06 FB09 FC01 FE01 4K029 BA02 BA21 BC00 CA03 DD06

Claims (9)

[Claims] 1. A base material for supporting a hydrogen selective permeable membrane, comprising a metal porous sintered body having a multilayer structure, wherein a relative density of the sintered body is at least 60% on a hydrogen selective permeable surface side.
And the average particle size of the sintered particles is 10 μm or more, and the average particle size of the sintered particles is 8 μm or less, the maximum particle size is 45 μm or less, and the opening area ratio is 30% or more on the crude gas contact surface side. A substrate for supporting a hydrogen-selective permeable membrane, comprising: 2. The hydrogen selective permeable membrane supporting substrate according to claim 1, wherein a diffusion preventing layer is formed on the surface of the sintered body on the side of the crude gas contact surface. 3. The hydrogen selective permeable membrane supporting substrate according to claim 1, wherein the diffusion preventing layer is an oxide film and / or a ceramic layer. 4. The substrate according to claim 1, wherein said porous sintered body is a sintered body of stainless steel. 5. The hydrogen selective permeable membrane supporting substrate according to any one of claims 1 to 4, wherein
A hydrogen selective permeable member formed with a hydrogen selective permeable membrane. 6. The hydrogen selective permeable member according to claim 5, wherein the hydrogen selective permeable membrane is a metal or alloy membrane having hydrogen selective permeability. 7. The hydrogen selective permeable member according to claim 6, wherein the metal or alloy is Pd or an alloy thereof. 8. The hydrogen selective permeable member according to claim 6, wherein the hydrogen selective permeable film is formed by a vapor deposition method. 9. The hydrogen selective permeable member according to claim 8, wherein the vapor phase film forming method is an arc ion plating method.