JP2007269595A - Hydrogen production system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydrogen production system which, while preventing the releasing or cracking of a porous support and a hydrogen-permeable membrane, prevents the diffusion and reaction between a metal component in the hydrogen-permeable membrane and a metal component in the porous substrate, and thus exhibits a long life even when used at a high temperature. <P>SOLUTION: There is provided the hydrogen production system 1 having the following characteristics: an adhesion layer 3, a barrier layer 4, and the hydrogen-permeable membrane 5 are formed sequentially on the surface of the porous substrate 2; the porous substrate 2 contains a catalyst metal component; the hydrogen-permeable membrane 5 contains a hydrogen-permeable metal; the barrier layer 4 is a porous layer having a layer not containing the catalyst metal component; and the adhesion layer 3 is a porous layer having a thermal expansion coefficient between that of the porous substrate 2 and that of the barrier layer 4. There is also provided the hydrogen production system 1 having the following characteristics: an adhesion layer 3, a barrier layer 4, and a hydrogen-permeable membrane 5 are formed sequentially on the surface of the porous substrate 2; the porous substrate 2, the hydrogen-permeable membrane 5, and the barrier layer 4 are each the same as those described above; and the adhesion layer 3 is a porous layer containing the catalyst metal component in a quantity smaller than that contained in the porous substrate 2. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a hydrogen production apparatus, and more particularly, to a hydrogen production apparatus excellent in high-purity hydrogen production performance and durability.

  Industrial production methods of hydrogen include water electrolysis, hydrocarbon steam reforming, partial oxidation of coal, heavy oil, etc., synthesis gas, and hydrogen production using water gas steam. In the steam reforming method of hydrocarbons and the partial oxidation method of coal and heavy oil, it is important to separate the hydrogen gas from the source gas containing impurity gases such as carbon dioxide, carbon monoxide, steam and methane. Many methods such as an absorption method, an adsorption method, and a membrane separation method are used for separation.

  On the other hand, recently, a hydrogen fuel cell is expected as a highly efficient small power generation device, and its technological development is rapidly progressing. In general, a hydrogen fuel cell is roughly divided into two parts, one is a battery body that takes out electric power by electrochemically reacting hydrogen and oxygen, and the other is a raw material for the battery body. This is a hydrogen production device. Hydrogen fuel cells are actively researched as distributed fuel cells and fuel cells for automobiles, but not only power generation performance and durability, but also miniaturization of automobile fuel cells is a major issue. There are two types of fuel cell vehicles, one with and without a hydrogen production device. For fuel cell vehicles with a hydrogen production device, it is very important to study not only the battery itself but also the size of the hydrogen production device. . Fuel cell vehicles without a hydrogen production device, for example, fuel cell vehicles with a hydrogen gas tank, require a facility such as a hydrogen supply station to replace the gas station, and produce hydrogen at the hydrogen supply station. It is considered to be. In that case, the hydrogen supply station must be installed on a relatively small site like the current gas station. Therefore, downsizing is also an important issue in such a hydrogen production apparatus.

  Furthermore, the hydrogen used in the battery body of the fuel cell needs to be highly purified in order to use it efficiently. Also, since a catalyst is used in the battery body, impurities such as carbon dioxide and carbon monoxide are likely to cause catalyst poisoning and deterioration of the equipment, and these impurities are very disliked. From this point, it is high-purity hydrogen. Is required. Therefore, in the steam reforming of hydrocarbons and the production of hydrogen from synthesis gas and water gas, it is essential to separate and purify hydrogen from a mixed gas having a low hydrogen purity. At the time of such hydrogen separation and purification in hydrogen production of a fuel cell system, it is particularly required to reduce the size of the apparatus, and a hydrogen separation apparatus based on a membrane separation method has been studied. The membrane separation method is a method for selectively separating and purifying hydrogen gas from a hydrogen-containing gas using a hydrogen permeable membrane that selectively permeates hydrogen gas such as palladium. This hydrogen permeable membrane is usually used by being formed on the surface of a porous support made of porous ceramics, porous glass, porous metal or the like. For example, a hydrogen separation system 16 as shown in FIG. 5 is known. In this hydrogen separation system 16, a hydrogen separator 15 in which a hydrogen permeable membrane is formed on the outer surface of a cylindrical porous support is housed in an outer cylinder 7 while being supported by a partition wall 8. A source gas for hydrogen separation is introduced from the source gas inlet 11, and only hydrogen gas permeates to the product gas channel 10 through the hydrogen separator 15 while passing through the source gas channel 9. Impurity gases such as carbon dioxide other than hydrogen flow through the porous support body of the raw material gas passage 9 and the hydrogen separator 15 to the downstream side of the raw material gas passage 9 and are discharged from the off-gas outlet 13 as off-gas. In this way, high purity hydrogen is separated and removed from the product gas outlet 12.

  On the other hand, in the hydrogen production, instead of separately performing the production of the hydrogen-containing gas as described above and the separation of the hydrogen gas from the hydrogen-containing gas, simultaneously with the production of the hydrogen-containing gas by steam reforming of hydrocarbons, A method for selectively separating and purifying hydrogen gas from this hydrogen-containing gas is known. For example, the raw material gas passage 9 of the hydrogen separator 15 in the hydrogen separation system as shown in FIG. 5 is made relatively thick, and the nickel-based catalyst for steam reforming of hydrocarbons in the raw material gas passage 9 is used. To produce hydrogen by supplying a mixed gas composed of high-temperature methane, which is a raw material gas for steam reforming, and water vapor from the raw material gas inlet 11 and simultaneously performing reaction and separation There is. The source gas becomes hydrogen, carbon monoxide, and carbon dioxide gas by the steam reforming reaction in the catalyst layer of the source gas flow path 9. Then, hydrogen flows out to the product gas flow path 10 through the porous support and the hydrogen permeable membrane forming the hydrogen separator 15. On the other hand, carbon dioxide, carbon monoxide, unreacted methane, residual water vapor, and the like are discharged from the off-gas outlet 13 as off-gas through the raw material gas passage 9. Thus, high-purity hydrogen can be produced by simultaneously performing the hydrogen production reaction and hydrogen separation.

  Furthermore, a hydrogen production system using an apparatus such as a membrane reactor is known. The membrane reactor has, for example, the same shape as the hydrogen separation system shown in FIG. 5, but includes a hydrogen production device having a hydrogen production function and a hydrogen separation function instead of the hydrogen separation device 15 shown in FIG. Yes. That is, in the membrane reactor, as described above, the raw material gas flow path 9 is not filled with a catalyst, but instead of the hydrogen separator, a catalyst / porous support in which a catalyst component is contained in a porous support, and the outside thereof. A hydrogen production apparatus having a hydrogen permeable membrane on the surface is provided. When FIG. 5 is regarded as a membrane reactor, in this membrane reactor, a raw material gas supplied from the raw material gas inlet 11 and reaches the raw material gas flow path 9, for example, a mixed gas of methane and steam forms a hydrogen production apparatus. When entering the porous support, a steam reforming reaction of methane occurs to generate hydrogen, and the generated hydrogen permeates through the hydrogen permeable membrane to the product gas flow path 10 to produce high purity hydrogen. Is taken from the product gas outlet 12. The remaining carbon dioxide, carbon monoxide, and the like are discharged as off-gas from the off-gas outlet 13 (see Patent Document 1 and Patent Document 2).

JP 2004-149332 A JP 2005-314163 A

  In the membrane reactor as described above, the hydrogen production apparatus usually includes a porous support and a hydrogen permeable membrane formed on the surface thereof. A metal component having a catalytic function for hydrogen production such as nickel is present in the porous support. In this case, when a hydrogen permeable membrane is formed on the surface of the porous support, during use of the hydrogen production apparatus at a high temperature, a part of the metal components in the porous support and the hydrogen permeable membrane are formed at these interfaces. Some metal components in the material to be formed may diffuse to each other. For example, nickel, which is a catalyst component in the porous support, and a metal component such as palladium, which is a component in the hydrogen permeable membrane, diffuse to each other. When the metal component in the hydrogen permeable membrane diffuses into the metal component in the porous support, the hydrogen permeable function and the hydrogen separation selectivity of the hydrogen permeable membrane naturally fall. Therefore, by interposing a barrier layer between the porous support and the hydrogen permeable membrane, the metal component of the material forming the porous support and the metal component of the material forming the hydrogen permeable membrane diffuse to each other. A method of preventing this and maintaining the performance of the hydrogen permeable membrane is conceivable. However, when a barrier layer having different properties from the porous support and the hydrogen permeable membrane is provided, a difference in thermal expansion coefficient occurs between the porous support and the barrier layer, and between the hydrogen permeable membrane and the barrier layer. easy. Between layers having different coefficients of thermal expansion, peeling and cracking are likely to occur due to temperature changes from 250 to 900 ° C., which is the operating temperature of the hydrogen production apparatus. An object of the present invention is to provide a hydrogen production apparatus that prevents diffusion and melting of the metal component in the hydrogen permeable membrane and the metal component in the porous support while preventing such peeling and cracking.

The present invention provides the following means in order to solve the above problems.
(1) An adhesion layer, a barrier layer, and a hydrogen permeable membrane are sequentially formed on the surface of the porous support. The porous support contains a catalytic metal component, the hydrogen permeable membrane contains a hydrogen permeable metal, and a barrier. The layer is a porous layer having a layer not containing the catalytic metal component, and the adhesion layer is a porous layer having a thermal expansion coefficient between the thermal expansion coefficient of the porous support and the thermal expansion coefficient of the barrier layer. Hydrogen production equipment.
(2) An adhesion layer, a barrier layer, and a hydrogen permeable membrane are sequentially formed on the surface of the porous support. The porous support contains a catalytic metal component, the hydrogen permeable membrane contains a hydrogen permeable metal, and a barrier. The hydrogen production apparatus, wherein the layer is a porous layer having a layer that does not contain the catalytic metal component, and the adhesion layer is a porous layer that contains fewer catalytic metal components than the porous support.
(3) The adhesion layer is composed of a plurality of layers, and the thermal expansion coefficient of the adhesion layer near the barrier layer is smaller than the thermal expansion coefficient of the adhesion layer near the porous support (1) or (2) The hydrogen production apparatus described in 1.
(4) The hydrogen production apparatus according to (1) or (2), wherein the thermal expansion coefficient in the adhesion layer continuously decreases from the porous support side to the barrier layer side of the adhesion layer.

  The hydrogen production apparatus of the present invention has good adhesion between the porous support and the hydrogen permeable membrane, and in particular, the heat between the porous support and the hydrogen separation membrane against temperature changes due to the use of the hydrogen production apparatus. There is no peeling or cracking due to strain, and it can be used for a long time without deformation of the porous support, damage to the hydrogen permeable membrane, and performance degradation. In addition, metal components such as palladium in the hydrogen permeable membrane do not diffuse into the porous support, and the life of the hydrogen permeable membrane is extended.

  As shown in FIG. 1, the hydrogen production apparatus of the present invention has at least four layers in which an adhesion layer 3, a barrier layer 4, and a hydrogen permeable membrane 5 are formed in this order on the surface of the porous support 2. Have The porous support 2 contains a catalytic metal component and has a hydrogen production catalyst function. The hydrogen permeable membrane 5 is a dense layer containing a hydrogen permeable metal and can selectively permeate hydrogen gas. The porous support 2, the adhesion layer 3, and the barrier layer 4 are all porous layers, and the source gas and the reaction gas at the time of hydrogen production freely flow from the porous support 2 side to the barrier layer 4. it can. However, only hydrogen gas can pass through the hydrogen permeable membrane 5. By the way, the porous support 2 is a layer containing a catalytic metal component, but the barrier layer 4 has at least one layer not containing the catalytic metal component, and in that case, usually the surface in contact with the adhesion layer 3. It is preferable to arrange a layer not containing the catalytic metal component.

In general, a layer containing a metal component (a metal component represents a metal or an alloy rather than a metal oxide or the like), for example, a composite layer of ceramics or glass and a metal component, has a thermal expansion as compared with a layer not containing a metal component. The rate tends to increase. For example, the thermal expansion coefficient of a porous body made from yttria stabilized zirconia powder is 9.67 × 10 ⁻⁶ / ° C., and the porous body made from the same yttria stabilized zirconia powder 40% by mass and nickel powder 60% by mass. The thermal expansion coefficient of the material is 12.05 × 10 ⁻⁶ / ° C. (The thermal expansion coefficient in the present invention represents the linear thermal expansion coefficient unless otherwise specified). When a multilayer structure made of porous materials with different coefficients of thermal expansion is subjected to temperature changes, thermal stress is generated at the interface, causing distortion, peeling, or cracking in one layer. Or Therefore, in the present invention, between the porous support 2 containing a metal component and having a large coefficient of thermal expansion, and the barrier layer 4 having a layer having a relatively small coefficient of thermal expansion and not containing a metal component, an intermediate between the two. The adhesion layer 3 having a thermal expansion coefficient of 2 is provided. The adhesion layer 3 has an effect of improving the bonding property between the porous support 2 and the barrier layer 4 when the hydrogen production apparatus 1 is produced, and the above-described temperature change when the hydrogen production apparatus 1 is used. Has the effect of reducing the effect of thermal stress.

In general, in order to make a multilayer structure having a strong bonding force between layers, it is preferable to form each layer with a similar material. In the case of this hydrogen production apparatus 1 as well, it is preferable to produce the barrier layer 4 and the adhesion layer 3 using the same ceramic material as the ceramic material that is one of the materials used for the porous support 2. In this case, in order to set the thermal expansion coefficient of the adhesion layer 3 to a value between the thermal expansion coefficient of the porous support 2 and the thermal expansion coefficient of the barrier layer 4, the other material contained in the porous support 2 is used. What is necessary is just to set it as the porous layer which contains the same metal component as this metal component in a ratio smaller than the porous support body 2. For example, the adhesion layer 3 formed on the porous support 2 made of 40% by mass of the yttria-stabilized zirconia powder and 60% by mass of the nickel powder is composed of 60% by mass of yttria-stabilized zirconia and 40% by mass of nickel powder. A porous layer made from 6 is a cross-sectional electron micrograph (SEM) of the porous support 2, the adhesion layer 3, and the yttria-stabilized zirconia barrier layer 4 corresponding to the structure of FIG. 1, and its energy dispersive X-ray. It is an analysis figure of an analyzer (EDS). 6A is an electron micrograph, and FIGS. 6B, 6C, and 6D are a catalytic metal component, an Ni element, a zirconia component, a Zr element, and a yttria component, respectively. It is an analysis figure of EDS of Y element. In these figures, the hydrogen permeable membrane 5 is not shown. It can be seen that the Ni element does not exist in the uppermost barrier layer 4 and the abundance of the Zr element and Y element increases in the order of the porous support 2, the adhesion layer 3, and the barrier layer 4. The thermal expansion coefficient measured by making a porous body with the same composition as the adhesion layer 3 is 11.25 × 10 ⁻⁶ / ° C., and the thermal expansion coefficient of the adhesion layer 3 is the thermal expansion coefficient and the barrier of the porous support 2. It becomes a value approximately in the middle of the thermal expansion coefficient of the layer 4. Thereby, not only the adhesiveness at the time of manufacture improves, but also the durability of the apparatus can be improved by suppressing the influence of thermal stress during use as a hydrogen production apparatus.

As described above, when the adhesion layer 3 is provided between the porous support 2 and the barrier layer 4, the influence of thermal stress during use as a hydrogen production apparatus can be suppressed, but this effect can be further improved. It is preferable to reduce the change in the coefficient of thermal expansion between the porous support 2 and the adhesion layer 3 and between the adhesion layer 3 and the barrier layer 4. For this purpose, the adhesion layer 3 has a multilayer structure, and the adhesion layer in contact with the porous support 2 has a value close to the coefficient of thermal expansion of the porous support 2 and is directed from the porous support 2 side toward the barrier layer 4 side. Thus, it is preferable that the thermal expansion coefficient of each layer in the adhesion layer is sequentially decreased so that the adhesion layer in contact with the barrier layer 4 approaches the thermal expansion coefficient of the barrier layer 4. For example, as shown in FIG. 2, when the adhesion layer has a two-layer structure composed of adhesion layers 3a and 3b, the material composition of the adhesion layer 3a is assumed to be the porous support 2 and the adhesion layer 4 described above. May be 60% by mass of the above-mentioned yttria-stabilized zirconia and 40% by mass of the nickel powder, and the material composition of the adhesion layer 3b may be 80% by mass of the above-mentioned yttria-stabilized zirconia and 20% by mass of the nickel powder. In this case, the thermal expansion coefficient of the adhesion layer 3a is 11.25 × 10 ⁻⁶ / ° C., and the thermal expansion coefficient of the adhesion layer 3b is 10.44 × 10 ⁻⁶ / ° C. The difference in thermal expansion coefficient between the bonding surface with the layer 3 and the bonding surface between the adhesion layer 3 and the barrier layer 4 is small.

  In this way, if the adhesion layer has a multi-layer structure and the adhesion layer with the reduced content of the catalyst metal used in the porous support is sequentially formed on the surface of the porous support, the porous support 2, the adhesion layer 3, The difference in the coefficient of thermal expansion is small not only on the bonding surface of the adhesive layer and the bonding surface of the adhesion layer 3 and the barrier layer 4, but also on the bonding surface of the adhesion layers having a multilayer structure, and is less susceptible to the influence of thermal stress and durability. It can be set as the hydrogen production apparatus with. As another example of this multilayer structure, an adhesive layer in which the content of the catalytic metal continuously decreases from the porous support side toward the barrier layer side can be provided. The catalytic metal content in the adhesion layer 3 is the same as that of the porous support 2 at the bonding surface between the porous support 2 and the adhesion layer 3, and at the bonding surface between the adhesion layer 3 and the barrier layer 4. Is preferably the same as that of the barrier layer 4. In addition, since the catalyst metal content in the barrier layer 4 is usually 0, in this case, the content of the catalyst metal in the adhesion layer 3 at the bonding surface between the adhesion layer 3 and the barrier layer 4 may be almost zero. In this way, although the adhesion layer is a single layer, the coefficient of thermal expansion can be continuously reduced from the porous support side in the adhesion layer toward the barrier layer side. The adhesion layer may be formed of a material that can obtain a desired coefficient of thermal expansion without necessarily including a metal component. For example, a porous material to which a small amount of MgO is added tends to have a large coefficient of thermal expansion, and is suitable for adjusting the coefficient of thermal expansion of the adhesion layer.

The barrier layer includes a layer that does not contain the catalytic metal component. In particular, the barrier layer preferably includes a layer that does not contain any metal component other than the catalyst. The barrier layer functions as a metal component of the hydrogen permeable membrane, such as palladium, which diffuses with the porous support or the metal in the adhesion layer to reduce the hydrogen separation function of the hydrogen permeable membrane, or to support the porous layer. It does not reduce the catalytic function of the body. When the barrier layer has a single-layer structure, any porous layer may be used as long as it does not contain the catalytic metal component. Usually, the metal material is made of the same material as that forming the porous support. It can be formed of a removed material, such as a ceramic material or a glass material. However, at the interface between the barrier layer and the hydrogen permeable membrane, there is a risk of peeling of the interface due to thermal stress or distortion, deformation, cracking, or breakage of the hydrogen permeable membrane as described above. The hydrogen permeable membrane is often made of a metal such as palladium, and its thermal expansion coefficient is, for example, about 12.55 × 10 ⁻⁶ / ° C. As a result, thermal stress is likely to occur at the bonding surface between the hydrogen permeable membrane and the above-described barrier layer having a thermal expansion coefficient of 9.67 × 10 ⁻⁶ / ° C. Since the hydrogen permeable membrane is relatively thin, it can cope with a certain amount of thermal stress, but the difference in the coefficient of thermal expansion at the joint surface should be small.

  Therefore, if the barrier layer has a multi-layer structure, for example, as shown in FIG. 3, two layers of the first barrier layer 4a and the second barrier layer 4b, the thermal expansion of the bonding surface between the hydrogen permeable film 5 and the barrier layer 4 is achieved. The difference in rate can be reduced and the generation of thermal stress at the joint surface can be suppressed. Here, a material having a thermal expansion coefficient close to that of the hydrogen permeable film 5 is used for the first barrier layer 4a as compared to the second barrier layer 4b. A metal such as palladium, which is a material component of the hydrogen permeable membrane 5, and a catalyst metal component contained in the porous support 2 described above are prevented from diffusing into the second barrier layer 4b. Thus, the function of the barrier layer 4 is to prevent the catalytic metal component such as nickel contained in the porous support 2 and the metal such as palladium contained in the hydrogen separation membrane 5 from diffusing each other. is there. Further, the first barrier layer 4a having a thermal expansion coefficient intermediate between these layers is interposed between the hydrogen permeable membrane 5 and the second barrier layer 4b to suppress a rapid change in the thermal expansion coefficient between the respective layers. Yes. As a specific method, for example, a first barrier layer 4a is formed by adding a metal component or metal oxide having a relatively high thermal expansion coefficient to the same ceramic component as that of the second barrier layer 4b. The thermal expansion coefficient of 4a can be brought close to the thermal expansion coefficient of the hydrogen permeable membrane. At this time, any metal component may be used as long as it can increase the coefficient of thermal expansion, but a metal component that is a material of the hydrogen permeable membrane, such as palladium, is preferable. If the metal component is the same as the material of the hydrogen permeable membrane, the composition of the hydrogen permeable membrane will not change greatly even if metals diffuse from the joint surface when the hydrogen production device is used at high temperatures. There will never be a failure. Other examples of the metal component to be added include gold, silver, and copper, and examples of the metal oxide to be added include magnesia. The second barrier layer 4b is preferably a layer that does not contain a metal component, so that a metal such as palladium that is a material component of the hydrogen permeable membrane does not diffuse into the second barrier layer.

  7 shows a laminate of the porous support 2, the adhesion layer 3, the yttria-stabilized zirconia barrier layer 4b, and the yttria-stabilized zirconia barrier layer 4a added with 40% by mass of magnesia corresponding to the structure of FIG. FIG. 2 is an analysis view of a cross-sectional electron micrograph (SEM) of FIG. The composition of the laminate shown in FIG. 7 is the same as that of the laminate shown in FIG. 6 except for the barrier layer. The first barrier layer 4a has a composition of 80% by mass of YSZ and 20% by mass of magnesia. The layer 4b has a composition of YSZ 100% by mass. FIG. 7A is an electron micrograph, and FIG. 7B, FIG. 7C, FIG. 7D, and FIG. 7E are a Ni element as a catalytic metal component and a Zr element as a component of zirconia, respectively. FIG. 6 is an analysis diagram of EDS of a Y element that is a yttria component and a Mg element that is a magnesia component. In these figures, the hydrogen permeable membrane 5 is not shown. It can be seen that the Ni element does not exist in the upper first barrier layers 4a and 4b, and the abundance of the Zr element and Y element increases in the order of the porous support 2, the adhesion layer 3, and the barrier layer 4b. . It can also be seen that Mg element is present in the uppermost second barrier layer 4b.

  Next, the composition and manufacturing method of the porous support constituting the hydrogen production apparatus will be described. The porous support has a function of permeating the source gas and the product gas after the reaction and a function of a reaction catalyst for the source gas. Furthermore, the hydrogen permeable membrane is usually supported by this porous support. Usually, the raw material gas components of a hydrogen production apparatus are hydrocarbons, alcohol, carbon monoxide, steam, etc., and the generated gas is a mixed gas such as carbon dioxide, carbon monoxide, water vapor, methane, etc. in addition to hydrogen. Since there are many cases, the material for forming the porous support is not particularly limited as long as it is a material that has a catalytic function of hydrogen production from a raw material gas, is not altered by these gases, and can support the hydrogen permeable membrane. . Such materials can be formed from non-catalytic components and catalytic components. Among these, examples of the non-catalytic component include inorganic oxides, carbon, and inorganic nitrides. Examples of the inorganic oxide include alumina (aluminum oxide), silica, silica-alumina, mullite, cordierite, zirconia, stabilized zirconia, and glass. Examples of the catalyst component include nickel used as a hydrocarbon steam reforming catalyst (also simply referred to as a reforming catalyst) in the case of a hydrogen production apparatus using hydrocarbon steam reforming. Specific examples of the porous support include a porous sintered body (referred to as Ni-YSZ cermet) mainly composed of a mixture of nickel and yttria-stabilized zirconia, porous ceramic added with nickel, and porous added with nickel. Glass or the like. In the case of a hydrogen production apparatus using synthetic gas or water gas as a raw material, porous ceramics or porous glass to which iron or chromium component or the like is added as a catalyst component can be cited as a porous support. The catalyst component can be appropriately selected depending on the raw material gas and the desired reaction.

In a nickel-added porous support, particularly Ni-YSZ cermet, the content of the Ni component in the Ni-YSZ cermet depends on the performance as a reforming catalyst, the material forming the supported hydrogen permeable membrane, and It is determined in consideration of various conditions such as the coefficient of thermal expansion with the hydrogen permeable membrane. For example, the content of the Ni component may be 1 to 99% by mass, preferably 30 to 85% by mass, and more preferably 50 to 70% by mass with respect to the entire Ni-YSZ cermet. When the hydrogen permeable membrane is formed of a material containing palladium or a palladium-silver alloy, the thermal expansion coefficient of the hydrogen permeable membrane depends on the amount of hydrogen gas that can be stored in the hydrogen permeable membrane. It varies between 10 × 10 ^{−6 and} 16 × 10 ⁻⁶ / ° C. Therefore, if the content of the Ni component in the Ni-YSZ cermet is adjusted, the thermal expansion coefficient of the Ni-YSZ cermet is set to a value close to the thermal expansion coefficient of the hydrogen permeable membrane, 9 × 10 ^{−6 to} 17 × 10 ^−. It can be adjusted to ⁶ / ° C. Thereby, the thermal stress generated by the temperature change during use of the hydrogen production apparatus can be reduced. If the metal component in the porous support is too small, the catalytic action tends to be insufficient, and if it is too large, the strength of the porous support at high temperatures may decrease.

  The porous support can be made by mixing, molding, and sintering the particles of the constituent components. For example, Ni-YSZ cermet is prepared by mixing and molding Ni particles or NiO particles and yttria-stabilized zirconia (also referred to as YSZ) particles, firing the resulting molded body, Ni-YSZ cermet having a catalytic action is obtained by reduction with the above. That is, the porous support only needs to have a catalytic function when a hydrogen production apparatus is used, and does not necessarily have a reforming catalytic function immediately after calcination to form the porous support. . In molding, a binder, carbon for forming pores, or the like can be added to the mixed particles. The firing condition varies depending on the melting point and particle size of the material to be fired, but is preferably 800 to 1500 ° C. and 0.5 to 48 hours.

  It is preferable that the porosity and the average pore diameter of the porous support are appropriately controlled. The porosity of the porous support is preferably 10 to 85%. When the porosity is less than 10%, the raw material gas does not flow quickly in the porous support, and the pressure loss may increase. In particular, the porous support also serves as a catalyst for hydrocarbon steam reforming. In some cases, the hydrocarbon may not be sufficiently reformed. On the other hand, when the porosity of the porous support exceeds 85%, the strength as the support may be lowered. The porosity here is defined as a value when measured by the Archimedes method. The porosity of the porous support is appropriately controlled in consideration of the strength of the support, the pressure loss when the raw material gas, the generated gas, and the off gas pass through the porous support.

  The average pore diameter of the pores of the porous support is preferably 0.05 to 30 μm. When this average pore diameter is less than 0.05 μm, the raw material gas, the generated gas and the off-gas do not flow quickly through the porous support, and the pressure loss may increase or the raw material gas may not be sufficiently reformed. . On the other hand, if the average pore diameter exceeds 30 μm, sufficient strength as a support may not be maintained. Here, the average pore diameter of the pores in the porous support is the arithmetic average obtained by observing the surface with an electron microscope such as a scanning electron microscope (SEM) and approximating the opening of the pores to a circle. This is the calculated value. In order to control the porosity and average pore diameter of the porous support within the above ranges, the particle size, particle size distribution and / or firing temperature of the powder used as the material for forming the porous support may be adjusted as appropriate. .

  The shape of the porous support is not particularly limited. The porous support is, for example, a plate, a hollow cylindrical or polygonal tube having both ends open, a hollow U-shaped tube having both ends open, a hollow spiral tube having both ends open, one end open and the other A hollow cylindrical shape or a polygonal cylindrical shape in which is closed. The size of the porous support may be determined according to the size of the membrane reactor or the like to be attached. The membrane reactor shown in FIG. 4 includes only one hydrogen production apparatus 1, but usually there are many cases where a large number of hydrogen production apparatuses are arranged and attached to the partition wall 8. In the hydrogen production apparatus, a hydrogen separation membrane is formed on the surface of a porous support through an adhesion layer and a barrier layer, and the shape of the hydrogen production apparatus is almost the same as the shape of the porous support.

  The adhesion layer is provided between the porous support and the barrier layer. The adhesion layer improves the adhesion between the porous support and the barrier layer, makes the surface state of the barrier layer uniform, reduces defects of the hydrogen permeable membrane due to the surface state of the barrier layer, and prevents the barrier of the hydrogen permeable membrane. Improves adhesion to the layer. As a result, the hydrogen permeable membrane can be formed thin and the hydrogen permeation performance can be improved. The adhesion layer may be considered to be a part of the porous support, and can be formed of material components similar to the porous support. The adhesion layer differs from the porous support in the coefficient of thermal expansion. As described above, the thermal expansion coefficient of the adhesion layer is a value between the thermal expansion coefficient of the porous support and the thermal expansion coefficient of the barrier layer. The adhesive layer preferably has a coefficient of thermal expansion that decreases from the porous support side toward the barrier layer side. From the viewpoint of the material composition, the adhesion layer contains the same catalytic metal as the catalytic metal in the porous support in a smaller composition than the porous support. Preferably, the catalytic metal content decreases from the porous support side toward the barrier layer side. Furthermore, preferably, the adhesion layer has a smaller average pore diameter than the porous support. Such an adhesion layer preferably has an average pore diameter of 0.05 to 10 μm on the surface thereof. If the average pore diameter is less than 0.05 μm, gas permeation may be hindered. On the other hand, if it exceeds 10 μm, the surface state of the barrier layer formed on the adhesion layer may not be effectively improved. The average pore diameter of pores on the surface of the adhesion layer is preferably 0.05 to 8 μm, and more preferably 0.05 to 7 μm. Here, the average pore diameter of the pores in the porous support is the arithmetic average obtained by observing the surface with an electron microscope such as a scanning electron microscope (SEM) and approximating the opening of the pores to a circle. This is the calculated value.

  The adhesion layer makes a slurry using a material having the same metal component content as that of the porous support, and the surface of the porous support before or after sintering is subjected to dip coating, spray spraying, What is necessary is just to shape | mold by methods, such as a printing method, and to sinter this molded object. The sintering conditions are the same as those for the porous support described above. The adhesion layer can improve the surface state of the barrier layer, and if the peeling from the porous support due to the thermal stress of the barrier layer can be prevented, the thickness of the adhesion layer is not particularly limited. it can. If the thickness of the adhesion layer is less than 0.1 μm, the barrier layer may be distorted or peeled off due to thermal stress, or the surface state of the barrier layer may not be effectively improved. On the other hand, the upper limit of the film thickness of the adhesion layer is not particularly limited. The film thickness can be adjusted to 100 μm, for example. A barrier layer is formed on the surface of the adhesion layer, and a hydrogen permeable film is further formed on the surface, thereby forming a hydrogen production apparatus.

  The barrier layer is a porous layer and is provided to protect the performance of the hydrogen permeable membrane from the influence of a metal component such as nickel present in the porous support. That is, when the hydrogen permeable membrane is formed directly on the surface of the porous support or the adhesion layer, the metal component that forms the porous support at the interface during use at high temperature, for example, the catalyst component in the porous support. Some nickel and a metal component forming the hydrogen permeable film, for example, a metal component such as palladium, which is a component in the hydrogen permeable film, may diffuse to each other, resulting in a decrease in performance. Therefore, by interposing a barrier layer between the porous support and the hydrogen permeable membrane, the metal component forming the porous support and the metal component forming the hydrogen permeable membrane are prevented from diffusing each other, The hydrogen permeation performance of the hydrogen permeable membrane and the catalytic function of the porous support are maintained. Therefore, the barrier layer should be formed of a porous material that prevents mutual diffusion between the metal component of the material forming the porous support and the metal component of the material forming the hydrogen permeable membrane and allows hydrogen gas to flow. For example, it is formed of a porous inorganic oxide or the like. Examples of the inorganic oxide include zirconia, stabilized zirconia, partially stabilized zirconia, alumina, magnesia, or a mixture or compound thereof. Usually, the barrier layer is often formed as a porous layer of a material excluding the catalyst component of the porous support, for example, yttria-stabilized zirconia.

  The barrier layer is made of the above-mentioned material by using, for example, a dip coating method, a spray spraying method, a printing method, etc. on a porous support on which an adhesion layer before or after sintering is formed. A thin layer can be formed from the slurry and sintered to form. Alternatively, the catalytic metal may be dissolved and removed from a part of the adhesion layer on the surface of the porous support. The catalyst metal is dissolved and removed by slightly thickening the adhesion layer, for example, 40 μm, and forming the barrier layer on the surface of the adhesion layer, for example, 20 μm thick, the metal that is a component in the porous support from the solvent or reaction What is necessary is just to elute using an agent. The solvent and the reactant used at this time are not particularly limited as long as the metal can be eluted. For example, when the adhesion layer and the porous support are formed of the Ni-YSZ cermet, Ni existing near the surface of the adhesion layer may be eluted using an acid solution such as sulfuric acid or hydrochloric acid. The thickness of the barrier layer is not particularly limited as long as the material component forming the porous support and the adhesion layer and the material component forming the hydrogen permeable membrane do not diffuse to each other. For example, the layer thickness is 5 to 100 μm. Adjusted to When the thickness of the barrier layer is less than 5 μm, mutual diffusion between the material component forming the porous support and the adhesion layer and the material component forming the hydrogen permeable membrane may not be prevented, while 100 μm may be prevented. If it exceeds, there is a risk of hindering the smooth hydrogen permeation of the hydrogen permeable member or reducing the hydrogen production function of the porous support.

  The hydrogen permeable membrane is a membrane that selectively permeates only hydrogen gas from a mixed gas such as methane, water vapor, hydrogen, carbon dioxide, carbon monoxide, which is a component of the source gas or reaction gas. The hydrogen permeable membrane is formed on the surface of the porous support via an adhesion layer and a barrier layer. For example, when the porous support is formed into a cylindrical body, the hydrogen permeable membrane may be formed so as to cover almost the entire outer surface of the porous support. It may be formed on the inner surface. FIG. 4 shows an example of a membrane reactor equipped with a hydrogen production apparatus in which a hydrogen permeable membrane is formed on almost the entire outer surface of a porous support. If the porous support is plate-shaped, a hydrogen permeable membrane may be formed on the surface on one side. A hydrogen production apparatus in which a hydrogen permeable membrane is formed on the surface of a porous support allows only hydrogen gas in the mixed gas to permeate from the porous support to the surface of the hydrogen permeable membrane and separate it from other gases. As shown in FIG. 4, it is preferable that the porous support surface is not exposed on the product gas flow path 10 side. If the surface of the porous support is exposed to the product gas 10 side, the components of the mixed gas other than the hydrogen gas leak to the product gas 10 side from this portion and the hydrogen purity in the product gas is lowered. Furthermore, it is preferable that the cross section of the hydrogen permeable membrane as a flow path through which hydrogen gas permeates is wide. Therefore, a hydrogen production apparatus in which a hydrogen permeable membrane is formed on almost the entire outer surface of the porous support shown in FIG. 4 is preferable.

  The material for forming the hydrogen permeable membrane may be any membrane as long as it selectively permeates only hydrogen gas in the mixed gas. Palladium, palladium alloy, periodic table 5th revised in 1989 Metals such as group elements and alloys containing these elements are preferably used. Examples of the Group 5 element include V, Nb, and Ta. Examples of the metal other than palladium and the group 5 element included in the alloy containing the palladium alloy and the group 5 element include, for example, group 3 elements (including lanthanoid elements) of the periodic table revised in 1989, group 8 Elements, Group 9 elements, Group 10 elements, Group 11 elements, or combinations of two or more thereof. Examples of Group 3 elements in the periodic table include Y, etc., examples of lanthanoid elements include Ce, Sm, Gd, Dy, Ho, Er, Yb, etc., examples of Group 8 elements include Ru, etc. Examples of the Group 9 element include Rh and Ir, examples of the Group 10 element include Pt, and examples of the Group 11 element include Cu, Ag, and Au.

  The hydrogen permeable membrane is formed on the surface of the porous support by, for example, a vacuum deposition method, an electroless plating method, a sputtering method, or the like. When the hydrogen permeable membrane is formed so that the material component of the hydrogen permeable membrane enters the pores on the surface of the barrier layer when the hydrogen permeable membrane is formed, the barrier effect is caused by the hook effect of the hydrogen permeable membrane component that has entered the pores. The hydrogen permeable film can be formed firmly on the layer, and the durability of the hydrogen permeable film is also improved. The thickness of the hydrogen permeable membrane is determined by the required hydrogen separation performance, such as the permeation rate and selectivity of hydrogen gas, the mechanical strength of the hydrogen permeable membrane, etc. It is preferable to adjust to 1 to 30 μm.

  Usually, the hydrogen separator of the present invention is used by being disposed in the membrane reactor shown in FIG. The membrane reactor shown in FIG. 4 will be briefly described. There is a hydrogen production apparatus 1 supported by a partition wall 8 in an outer cylinder 7. The outer cylinder 7 and the partition wall 8 are preferably made of metal from the viewpoints of strength, denseness, thermal shock resistance and the like as long as the usage conditions do not exceed 900 ° C. Examples of the metal include iron, steel, copper, iron, nickel, copper, chromium, aluminum, boron, silicon, molybdenum, tungsten, or alloys thereof, stainless steel, inconel, and kovar.

  When this membrane reactor is used, for example, for hydrogen production by hydrocarbon steam reforming, it is preferable to add a nickel-based catalyst component as a component of the porous support and react at 500 to 900 ° C. Then, the hydrogen production performance of the reforming catalyst and the hydrogen separation performance of the hydrogen permeable membrane can be sufficiently exhibited. Moreover, when steam reforming alcohol, such as methanol, the reaction temperature should just be 250-600 degreeC using the porous support body of the same catalyst component. In hydrogen production from synthesis gas or water gas, an iron-based or chromium-based catalyst component can be contained in the porous support and reacted at 200 to 500 ° C. In hydrogen production by hydrocarbon steam reforming, for example, when methane is used as a raw material gas, the reforming temperature is 600 ° C., and the ratio of steam molecules to carbon atoms in the raw material (usually referred to as S / C). ) Is 3.0, a methane conversion rate of about 58% can be obtained, and the steam reforming performance is almost the same as that of a normally used granular steam reforming catalyst. In the hydrogen production apparatus of the present invention in which such reaction and hydrogen separation are performed simultaneously, since hydrogen is separated from the product gas simultaneously with the reaction, the reaction is not subject to thermodynamic equilibrium restrictions. The conversion rate of can be increased. For this reason, pure hydrogen can be produced with very high efficiency.

Example 1
In 300 parts by mass of water, 60 parts by mass of NiO powder (average particle size 0.5 μm) and zirconia (hereinafter simply referred to as “8YSZ”) powder in which 8 mol% of yttria are solid-dissolved (average particle size 0. 5 μm) 40 parts by mass, 20 parts by mass of artificial graphite powder as a pore-forming agent, and 5 parts by mass of an acrylic copolymer as a binder were mixed to prepare slurry A. This slurry A was granulated by spray drying. The obtained granulated body was pressure-molded into a hollow cylindrical shape, degreased, and then fired at 1400 ° C. for 1 hour to prepare a porous support formed of NiO-8YSZ cermet. The porous support was 9 mm in outer diameter, 7 mm in inner diameter, and 100 mm in length. The porosity of the porous support, the average pore diameter of the pores on the surface, and the number of pores per unit area were determined by the above-described methods. As a result, the porosity of this porous support 1 was 48%, the average pore diameter was 16 μm, and the number of pores per unit area was 1.3 × 10 ⁵ / cm ² . This porous support was designated as porous support X.

In 300 parts by mass of ethanol, 20 parts by mass of NiO powder, 80 parts by mass of 8YSZ powder, 20 parts by mass of artificial graphite powder, and 5 parts by mass of binder were mixed to prepare slurry C. The slurry C was dip coated on the outer surface of the porous support X. The dip coating of slurry C was repeated several times so that the layer thickness after firing was about 20 μm. The porous support X coated with the slurry C by dip coating was fired at 1400 ° C. for 1 hour to form an adhesion layer. The average pore diameter of the pores on the surface of this adhesion layer was 2.7 μm, and the number of pores was 8.2 × 10 ⁶ / cm ² . The porous support X on which the adhesion layer was formed was used as an adhesion layer-forming porous support U1.

  In 300 parts by mass of ethanol, 100 parts by mass of the above 8YSZ powder and 5 parts by mass of the binder were mixed to prepare slurry D. This slurry D was dip-coated on the outer surface of the adhesion layer-forming porous support U1. This operation was repeated several times so that the layer thickness after firing was about 20 μm. The adhesion layer forming porous support U1 dip coated with the slurry D was baked at 1300 ° C. for 1 hour to form a barrier layer. The average pore diameter of the pores on the surface of this barrier layer was 0.2 μm. The adhesion layer forming porous support U1 on which this barrier layer was formed was designated as a barrier layer forming porous support V1.

The barrier layer-forming porous support V1 was ultrasonically washed in ethanol for 30 minutes and then dried at 120 ° C., and a hydrogen permeable film was formed on the surface of the barrier layer by electroless plating. In the electroless plating, first, an opening is closed with a rubber stopper so that the solution does not enter the cylinder of the barrier layer forming porous support V1, and this is placed in an aqueous HCl solution containing SnCl ₂ .2H ₂ O for 1 minute. After soaking, the substrate is washed with distilled water, immersed in an aqueous HCl solution containing PdCl ₂ for 1 minute, and then washed with distilled water. This SnCl ₂ .2H ₂ O treatment and PdCl ₂ treatment are repeated three times. Next, a plating solution composed of Pd (NH ₃ ) ₄ Cl ₂ , EDTA · 2Na, aqueous ammonia and hydrazine aqueous solution was prepared, and the barrier layer-forming porous support V1 treated as described above was subjected to a plating solution at 50 ° C. under normal pressure. And dipping until the plating thickness is 1.5 μm. Thereafter, the inside of the cylinder of the barrier layer-forming porous support X2 was depressurized, and dipped again in the plating solution, so that the total plating thickness was 9.0 μm. For reducing the pressure inside the cylinder, a Teflon (registered trademark) tube was connected to a rubber stopper attached to the opening to reduce the pressure. By this treatment, a hydrogen permeable membrane having a thickness of 9 μm was formed on the surface of the barrier layer-forming porous support V1. The barrier layer-forming porous support V1 on which this hydrogen permeable membrane was formed was used as the hydrogen production apparatus Z1.

(Example 2)
A slurry B was prepared by mixing 40 parts by mass of NiO powder, 60 parts by mass of 8YSZ powder, 20 parts by mass of artificial graphite powder, and 5 parts by mass of a binder used in Example 1 in 300 parts by mass of ethanol. The slurry B was dip-coated on the outer surface of the porous support X prepared in Example 1 so that the layer thickness after firing was about 10 μm. The slurry C prepared in Example 1 was further dip-coated on the outer surface of the porous support X dip-coated with the slurry B so that the layer thickness after firing was about 10 μm. This was fired in the same manner as in Example 1 to form an adhesion layer. This was designated as an adhesion layer-forming porous support U2. A barrier layer was formed on the adhesion layer-forming porous support U2 in the same manner as in Example 1. The adhesion layer forming porous support U2 on which this barrier layer was formed was used as a barrier layer forming porous support V2. Further, a hydrogen permeable membrane was formed on the barrier layer-forming porous support V2 in the same manner as in Example 1. The barrier layer-forming porous support V2 on which this hydrogen permeable membrane was formed was used as the hydrogen production apparatus Z2.

(Example 3)
The slurry D was dip coated on the outer surface of the adhesion layer-forming porous support U1 prepared in Example 1 so that the layer thickness after firing was about 10 μm. Furthermore, 40 mass parts of MgO powder (average particle diameter of 0.5 μm) was used in Example 1 in 300 mass parts of ethanol on the outer surface of the adhesion layer forming porous support U1 dip-coated with the slurry D. A slurry E prepared by mixing 60 parts by mass of 8YSZ powder, 20 parts by mass of artificial graphite powder and 5 parts by mass of a binder was dip-coated so that the layer thickness after firing was about 10 μm. Thereafter, the adhesion layer-forming porous support U1 dip-coated with this slurry E was fired in the same manner as in Example 1 to form a barrier layer. This was designated as a barrier layer-forming porous support V3. A hydrogen permeable membrane was formed in the same manner as in Example 1 on the outer surface of the barrier layer-forming porous support V3. The barrier layer forming porous support V3 on which this hydrogen permeable membrane was formed was used as the hydrogen production apparatus Z3.

(Comparative Example 1)
The slurry D is directly dip-coated on the outer surface of the porous support X prepared in Example 1 so that the layer thickness after firing is about 20 μm, and fired in the same manner as in Example 1 to form a barrier layer. did. This was designated as barrier layer-forming porous support V4. A hydrogen permeable membrane was formed in the same manner as in Example 1 on the outer surface of the barrier layer-forming porous support V4. The barrier layer forming porous support V4 on which this hydrogen permeable membrane was formed was used as the hydrogen production apparatus Z4.

(Measurement of thermal expansion coefficient)
The raw materials were adjusted with the same composition as that of the slurry A to E, respectively, pressed, and fired at 1400 ° C. for 1 hour. It processed so that it might become a prism of 20 mm x 3 mm x 3 mm after baking, and the test pieces 1-5 for a thermal expansion coefficient measurement were created. The linear thermal expansion coefficient was measured at 30 to 600 ° C. for each of the test pieces 1 to 5. Table 1 shows the measurement results of the coefficient of linear thermal expansion. The hydrogen permeable membrane was made of a linear thermal expansion coefficient of palladium metal.

(Evaluation of heat resistance of hydrogen production equipment)
The heating and cooling cycle in which the hydrogen production apparatuses Z1 to Z4 created in Examples 1 to 3 and Comparative Example 1 were each heated at 600 ° C. for 1 hour in a thermostatic bath and then allowed to stand at room temperature for 5 hours was repeated 10 times. Thereafter, the hydrogen production apparatuses Z1 to Z4 were taken out, and the peeling state between the respective layers of the opening section of the hydrogen production apparatus and the cracks and deformation of the hydrogen separation membrane on the outer surface were visually evaluated. The evaluation results are shown in Table 2.

  As can be seen from the above evaluation results, compared with the hydrogen production apparatus Z4 of the comparative example, the hydrogen production apparatuses of Examples 1 to 3, especially Examples 2 and 3, have a strong structure against the heating and cooling cycle. I understand.

  The hydrogen production apparatus of the present invention can also be used for production of high-purity hydrogen for industrial use including hydrogen fuel cells.

FIG. 1 is an example of a sectional structural view of a hydrogen production apparatus of the present invention. FIG. 2 is an example of a sectional structural view of the hydrogen production apparatus of the present invention. FIG. 3 is an example of a sectional structural view of the hydrogen production apparatus of the present invention. FIG. 4 is a cross-sectional view of a hydrogen production system incorporating the hydrogen production apparatus of the present invention. FIG. 5 is a cross-sectional view of a hydrogen separation system incorporating a conventional hydrogen separation apparatus. FIG. 6 is a cross-sectional electron micrograph (SEM) of the porous support, the adhesion layer, and the barrier layer corresponding to the structure of FIG. 1, and an analysis diagram of the energy dispersive X-ray analyzer (EDS). 6A is an electron micrograph, and FIGS. 6B, 6C, and 6D are analysis diagrams of EDS of Ni, Zr, and Y elements, respectively. FIG. 7 is a cross-sectional electron micrograph (SEM) of the porous support, the adhesion layer, and the barrier layer corresponding to the structure of FIG. 3, and an analysis diagram of the energy dispersive X-ray analyzer (EDS). FIG. 7A is an electron micrograph, and FIG. 7B, FIG. 7C, FIG. 7D, and FIG. 7E are analysis diagrams of EDS of Ni, Zr, Y, and Mg elements, respectively. .

Explanation of symbols

1: hydrogen production apparatus, 2: porous support, 3, 3a, 3b: adhesion layer,
4: barrier layer, 4a: first barrier layer, 4b: second barrier layer,
5: hydrogen permeable membrane, 7: outer cylinder, 8: partition wall,
9: Raw material gas flow path, 10: Product gas flow path, 11: Raw material gas inlet,
12: Product gas outlet, 13: Off-gas outlet, 14: Membrane reactor,
15: Hydrogen separator, 16: Hydrogen separation system

Claims (4)

  An adhesion layer, a barrier layer, and a hydrogen permeable membrane are sequentially formed on the surface of the porous support, the porous support contains a catalytic metal component, the hydrogen permeable membrane contains a hydrogen permeable metal, Hydrogen production apparatus comprising a porous layer having a layer not containing a catalytic metal component, and the adhesion layer being a porous layer having a thermal expansion coefficient between the thermal expansion coefficient of the porous support and the thermal expansion coefficient of the barrier layer .   An adhesion layer, a barrier layer, and a hydrogen permeable membrane are sequentially formed on the surface of the porous support, the porous support contains a catalytic metal component, the hydrogen permeable membrane contains a hydrogen permeable metal, An apparatus for producing hydrogen, which is a porous layer having a layer not containing a catalytic metal component, and the adhesion layer is a porous layer containing a smaller amount of the catalytic metal component than a porous support.   The hydrogen production according to claim 1 or 2, wherein the adhesion layer comprises a plurality of layers, and the thermal expansion coefficient of the adhesion layer near the barrier layer is smaller than the thermal expansion coefficient of the adhesion layer near the porous support. apparatus.   The hydrogen production apparatus according to claim 1 or 2, wherein the thermal expansion coefficient in the adhesion layer continuously decreases from the porous support side to the barrier layer side of the adhesion layer.

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