Hydrogen separation member

Abstract

This hydrogen separation member comprises a base material and a first membrane. The base material has a plurality of crystal grains. The first membrane is positioned so as to cover at least one of the plurality of crystal grains, and includes Ti and N.

Description

Hydrogen separation material

[0001] The present disclosure relates to hydrogen separation members.

[0002] In response to the recent increase in demand for hydrogen, development of hydrogen separation membranes that can selectively permeate and separate hydrogen from a hydrogen-containing mixed gas has been progressing. For example, a technology using a TiN (titanium nitride) membrane as a hydrogen separation membrane has been disclosed (see Patent Document 1).

[0003] International Publication No. 2019 / 131792

[0004] The hydrogen separation element of the present disclosure includes a substrate having a plurality of crystal grains, and a first membrane, the first membrane being positioned so as to cover at least one of the plurality of crystal grains, and containing Ti and N.

[0005] FIG. 1 is a cross-sectional view showing an example of the configuration of a hydrogen separation member according to an embodiment. FIG. 2 is a cross-sectional view taken along the line A-A in FIG. 1. FIG. 3 is an enlarged cross-sectional view showing an example of the configuration of a hydrogen separation membrane and its periphery according to an embodiment. FIG. 4 is an enlarged cross-sectional view showing an example of the configuration of a hydrogen permeation layer according to an embodiment. FIG. 5 is an enlarged cross-sectional view showing another example of the configuration of a hydrogen separation membrane and its periphery according to an embodiment. FIG. 6 is a cross-sectional view showing an example of the configuration of a hydrogen separation member according to another embodiment 1. FIG. 7 is a cross-sectional view showing an example of the configuration of a hydrogen separation member according to another embodiment 2. FIG. 8 is a perspective view showing an example of the configuration of a hydrogen separation member according to another embodiment 3.

[0006] Hereinafter, a hydrogen separation member according to the present disclosure will be described in detail with reference to the drawings. However, the present disclosure is not limited to the embodiment.

[0007] It should also be noted that the drawings are schematic and that the dimensional relationships and ratios of elements may differ from reality. Furthermore, the drawings may contain parts whose dimensional relationships and ratios differ from one another.

[0008] In response to the recent increase in demand for hydrogen, development of hydrogen separation membranes that can selectively permeate and separate hydrogen from a hydrogen-containing mixed gas has been progressing. For example, a technology using a TiN membrane as a hydrogen separation membrane has been disclosed.

[0009] However, the above-mentioned conventional technology leaves room for further improvement in terms of increasing the area of ​​the hydrogen separation membrane and improving the hydrogen separation performance.

[0010] <Configuration of Hydrogen Separator> First, the configuration of the hydrogen separator 1 according to the embodiment will be described with reference to Figures 1 to 5. Figure 1 is a cross-sectional view showing an example of the configuration of the hydrogen separator 1 according to the embodiment. Figure 2 is a cross-sectional view taken along the line A-A in Figure 1.

[0011] 1 and 2, a hydrogen separation member 1 according to an embodiment may include a substrate 10 and a hydrogen separation membrane 20. The substrate 10 may be tubular, for example, cylindrical. The length of the substrate 10 in the extension direction may be, for example, approximately 400 mm to 2000 mm.

[0012] A single through hole S extending in the extension direction of the substrate 10 may be located inside the substrate 10. The substrate 10 may have an inner circumferential surface 10a facing the through hole S and an outer circumferential surface 10b located on the opposite side to the inner circumferential surface 10a. The inner circumferential surface 10a is an example of a surface.

[0013] The substrate 10 may have a first end 10c, which is an end on the side where the mixed gas G is introduced, and a second end 10d, which is an end on the opposite side to the first end 10c. The mixed gas G is a gas that is the target of the hydrogen separation process performed by the hydrogen separation member 1, and hydrogen gas H ２ Contains:

[0014] The material of the substrate 10 is, for example, Al. ２ O ３ The substrate 10 may be made of ceramics such as alumina. The substrate 10 may have a polycrystalline structure. The substrate 10 may be made of a porous material having pores through which gas can pass. This allows hydrogen gas H ２Since there are many pores through which hydrogen gas H passes, the hydrogen gas H ２ can be moved smoothly.

[0015] The hydrogen separation membrane 20 separates hydrogen gas H ２ selectively permeates hydrogen gas H ２ The hydrogen separation membrane 20 may have a property of being difficult to permeate gases other than hydrogen gas H ２ 1 and 2, the hydrogen separation membrane 20 may be located on the inner circumferential surface 10a of the substrate 10.

[0016] 3 is an enlarged cross-sectional view showing an example of the configuration of the hydrogen separation membrane 20 and its surroundings according to the embodiment, and is an enlarged view of part B shown in FIG. 1. As shown in FIG. 3, the hydrogen separation membrane 20 according to the embodiment may have a hydrogen permeation layer 21 and a separation portion 22.

[0017] The hydrogen permeation layer 21 may be located above the inner circumferential surface 10a of the substrate 10. Alternatively, as shown in Fig. 4, the hydrogen permeation layer 21 may be composed of an aggregate of a plurality of coated particles 21a. Fig. 4 is an enlarged cross-sectional view showing an example of the configuration of the hydrogen permeation layer 21 according to the embodiment.

[0018] 4, the coated particles 21a constituting the hydrogen permeation layer 21 may have crystal grains P1 and a first film 21b. The crystal grains P1 are particles constituting the substrate 10 (see FIG. 3). That is, the substrate 10 is composed of a plurality of crystal grains P1.

[0019] The first film 21b may be positioned so as to cover the surface P1a of at least one crystal grain P1 among the plurality of crystal grains P1 constituting the substrate 10. The first film 21b may cover the surface P1a of at least one crystal grain P1 among the various gases contained in the mixed gas G (see FIG. 1). ２ (see FIG. 1) and hydrogen gas H ２ The first membrane 21b may have a property of being difficult to permeate gases other than hydrogen gas H ２ Other gases may not be allowed to permeate.

[0020] The first film 21b may contain, for example, Ti (titanium) and N (nitrogen), or may be a TiN (titanium nitride) film. When the first film 21b has a TiN crystal structure, hydrogen is converted into hydride ions (H － ) can permeate while diffusing through the grain boundaries, while elements constituting other gases are less likely to permeate. ２ can be selectively transmitted.

[0021] In the present disclosure, the first film 21b is not limited to a TiN film, and may be a hydrogen gas H ２ Alternatively, the hydrogen separation membrane 20 including the first membrane 21b may be any other membrane that can selectively transmit hydrogen gas H, such as a palladium membrane, a vanadium alloy membrane, a silica membrane, a zeolite membrane, or a polymer membrane. ２ can be selectively transmitted.

[0022] On the other hand, since the first film 21b is a TiN film, hydrogen gas H ２ Furthermore, since the first membrane 21b is a TiN membrane, it can selectively transmit hydrogen gas H 2 more efficiently than zeolite membranes and polymer membranes. ２ The separation performance can be improved.

[0023] Returning to the explanation of Fig. 3, the separation portion 22 may be a layer that contacts the hydrogen permeation layer 21 on the opposite side of the inner circumferential surface 10a of the substrate 10. The separation portion 22 is formed by, for example, converting hydrogen gas H ２ may have the property of converting H to a hydride ion. ２ + 2e － → 2H － ...(1)

[0024] The separation portion 22 may contain at least one element selected from the group consisting of Hf (hafnium), Zr (zirconium), Ti, Mn (manganese), Fe (iron), Ni (nickel), Co (cobalt), Ir (iridium), Ru (ruthenium), Pt (platinum), Rh (rhodium), and Pd (palladium). The separation portion 22 may also contain oxides of these elements. This allows hydrogen gas H ２ can be efficiently converted into a hydride ion.

[0025] When the first membrane 21b is formed of a membrane other than a TiN membrane, the separation portion 22 may be omitted from the hydrogen separation membrane 20. The separation portion 22 may be positioned so as to sandwich the hydrogen permeation layer 21 therebetween.

[0026] 4, in the embodiment, the first film 21b may be located on each of the surfaces P1a of the plurality of crystal grains P1, thereby increasing the area of ​​the first film 21b having the hydrogen separation function.

[0027] In the embodiment, the hydrogen separating member 1 may also include a hydrogen permeation layer 21 composed of an aggregate of a plurality of coated particles 21 a having a first membrane 21 b. In other words, the hydrogen permeation layer 21 having a layered structure composed of an aggregate of a plurality of coated particles 21 a may impart a hydrogen separating function to the hydrogen separating member 1.

[0028] As a result, the first membrane 21b having the hydrogen separation function becomes continuous, and hydrogen gas H ２ Therefore, according to the embodiment, the hydrogen gas H ２ The separation performance can be improved.

[0029] In the embodiment, the hydrogen permeation layer 21 formed of an aggregate of coated particles 21 a may be located on at least a part of the inner circumferential surface 10 a of the substrate 10 (see FIG. 1 ).

[0030] In this way, the hydrogen permeation layer 21 having a hydrogen separation function is located on the inner peripheral surface 10a of the cylindrical substrate 10, thereby improving the contact between the mixed gas G flowing through the through holes S (see FIG. 1) of the substrate 10 and the hydrogen separation membrane 20. Therefore, according to the embodiment, the hydrogen gas H ２ The separation performance can be improved.

[0031] In the example of FIG. 1, the hydrogen gas H separated from the mixed gas G by the hydrogen separating member 1 ２ may be collected from the outer peripheral surface 10b of the substrate 10.

[0032] Furthermore, in the embodiment, the thickness of the first film 21b at a position close to the inner circumferential surface 10a of the substrate 10 may be greater than the thickness of the first film 21b at a position far from the inner circumferential surface 10a of the substrate 10. For example, when the thickness of the hydrogen permeation layer 21 is T, the region from the inner circumferential surface 10a to T / 3 may be considered to be close to the inner circumferential surface 10a, and the region at least 2×T / 3 away from the inner circumferential surface 10a may be considered to be far from the inner circumferential surface 10a.

[0033] In the present disclosure, the thickness of the first film 21b refers to the distance between the surface P1a of the crystal grain P1 and the outermost surface 21b1 of the first film 21b, as shown in FIG. 4, in the first film 21b located on the surface P1a of the crystal grain P1.

[0034] The thickness of the first film 21b at a position close to the inner circumferential surface 10a of the substrate 10 may be the average value of the distance between the surface P1a in a region from the inner circumferential surface 10a to T / 3 and the outermost surface 21b1 of the first film 21b, i.e., the average thickness. The thickness of the first film 21b at a position far from the inner circumferential surface 10a of the substrate 10 may be the average value of the distance between the surface P1a in a region 2×T / 3 or more away from the inner circumferential surface 10a and the outermost surface 21b1 of the first film 21b, i.e., the average thickness.

[0035] In this way, by making the thickness of the first film 21b larger at a position closer to the inner circumferential surface 10a than at a position farther from the inner circumferential surface 10a, the hydrogen gas H ２ Therefore, according to the embodiment, the hydrogen gas H ２The separation performance can be improved.

[0036] In addition, in the embodiment, the size of the multiple crystal grains P1 at a position far from the inner peripheral surface 10a of the substrate 10 may be larger than the size of the multiple crystal grains P1 at a position close to the inner peripheral surface 10a of the substrate 10.

[0037] The size of the crystal grains P1 refers to the average particle diameter of the crystal grains P1. The size of the crystal grains P1 at a position far from the inner circumferential surface 10a may be, for example, the average particle diameter of the crystal grains P1 in a region that is 2×T / 3 or more away from the inner circumferential surface 10a. The size of the crystal grains P1 at a position close to the inner circumferential surface 10a may be the average particle diameter of the crystal grains P1 in a region from the inner circumferential surface 10a to T / 3.

[0038] The crystal grains P1 gradually become smaller from a distant position to a closer position on the inner circumferential surface 10a of the substrate 10, so that the surface area of ​​the first film 21b can be increased the closer it is to the inner circumferential surface 10a.

[0039] As a result, in the hydrogen separation process, the first membrane 21b is separated from the hydrogen gas H ２ Even if gases other than hydrogen gas H pass through, the base material 10 exhibits a molecular sieve effect near the inner peripheral surface 10 a, and hydrogen gas H ２ Therefore, according to the embodiment, the permeation of hydrogen gas H ２ The separation performance can be improved.

[0040] 4, the plurality of coated particles 21a may include a first coated particle 21a1 and a second coated particle 21a2 adjacent to the first coated particle 21a1. The first film 21b of the second coated particle 21a2 may be continuous with the first film 21b of the first coated particle 21a1. In other words, the first films 21b of the first coated particle 21a1 and the second coated particle 21a2 adjacent to each other may be in contact with each other, or may be connected to each other and integrated.

[0041] In this way, the first film 21b of the first coated particle 21a1 and the first film 21b of the second coated particle 21a2 are continuous, so that the hydrogen gas H ２ Furthermore, since the first film 21b of the first coated particle 21a1 and the first film 21b of the second coated particle 21a2 are continuous, the number of paths for hydride ions and electrons increases, thereby increasing the amount of hydride ions that permeate.

[0042] Therefore, according to the embodiment, the hydrogen gas H ２ The separation performance can be improved.

[0043] In the embodiment, the second coated particle 21a2 may be adjacent to the first coated particle 21a1 in the planar direction D1. In the examples shown in Figures 1 to 4, the planar direction D1 refers to the direction along the inner circumferential surface 10a, as shown in Figure 3.

[0044] In this way, the first film 21b of the first coated particle 21a1 and the first film 21b of the second coated particle 21a2 adjacent to each other in the planar direction D1 are continuous, so that the hydrogen gas H ２ Therefore, according to the embodiment, the hydrogen gas H ２ The separation performance can be improved.

[0045] In an embodiment, the second coated particle 21a2 may be adjacent to the first coated particle 21a1 in the depth direction D2. In the examples shown in Figures 1 to 4, the depth direction D2 refers to the direction perpendicular to the inner circumferential surface 10a, as shown in Figure 3.

[0046] In this way, the first film 21b of the first coated particle 21a1 and the first film 21b of the second coated particle 21a2, which are adjacent to each other in the depth direction D2, are continuous, which increases the number of paths for hydride ions and electrons, thereby increasing the amount of hydride ions that permeate the hydrogen gas H ２ The separation performance can be improved.

[0047] In addition, in the embodiment, the thickness of the first film 21b on the first end 10c side of the substrate 10 may be greater than the thickness of the first film 21b on the second end 10d side of the substrate 10.

[0048] For example, where the length from the inlet to the outlet of the substrate 10 is L, the region from the inlet to L / 3 may be defined as the first end 10c side, and the region from the outlet to L / 3 may be defined as the second end 10d side. In this case, the thickness of the first film 21b on the first end 10c side may be the average thickness of the first film 21b in the region from the inlet to L / 3. The thickness of the first film 21b on the second end 10d side may be the average thickness of the first film 21b in the region from the outlet to L / 3.

[0049] In this way, by making the thickness of the first film 21b larger on the first end 10c side, which is the inlet side of the mixed gas G, than on the second end 10d side, which is the outlet side, the pressure of the hydrogen gas H ２ It is possible to make it more difficult for gases other than the above to permeate.

[0050] Therefore, according to the embodiment, the hydrogen gas H ２ Therefore, the separation performance can be maintained well.

[0051] In the embodiment, the first film 21b may be formed by chemical vapor deposition (CVD). In this case, the first film 21b may be formed by, for example, TiCl ４ (titanium tetrachloride) and H ２ And, N ２ or NH ３ The film may be formed using the above as a source gas. This allows a high-quality TiN film to be formed.

[0052] In the embodiment described so far, an example has been shown in which the hydrogen separation membrane 20 is configured with the hydrogen permeation layer 21 and the separation portion 22, but the present disclosure is not limited to such an example. Fig. 5 is an enlarged cross-sectional view showing another example of the configuration of the hydrogen separation membrane 20 and its surrounding area according to the embodiment.

[0053] 5, the hydrogen separation membrane 20 may be composed of a hydrogen permeation layer 21, a second membrane 23, and a separation portion 22. The hydrogen permeation layer 21 has the same structure as in the above-described embodiment, and therefore a detailed description thereof will be omitted.

[0054] The second film 23 may be a layer that is in contact with the hydrogen permeation layer 21 on the inner peripheral surface 10a of the substrate 10. The second film 23 is a layer that is in contact with the hydrogen permeation layer 21 on the inner peripheral surface 10a of the substrate 10. The second film 23 is a layer that is in contact with the hydrogen gas H ２ (see FIG. 1) and hydrogen gas H ２ The second membrane 23 may have a property of being difficult to permeate gases other than hydrogen gas H ２ Other gases may not be allowed to permeate.

[0055] The second film 23 may contain, for example, Ti and N, or may be a TiN film. When the second film 23 has a crystal structure of TiN, hydrogen can permeate while diffusing through the grain boundaries in the form of hydride ions, while other gas constituent elements are less likely to permeate. Therefore, the second film 23 is less permeable to hydrogen gas H ２ can be selectively transmitted.

[0056] In the present disclosure, the second film 23 is not limited to a TiN film, and may be a hydrogen gas H ２ Alternatively, the hydrogen separation membrane 20 including the second membrane 23 may be any other membrane that can selectively pass hydrogen gas H 2 , such as a palladium membrane, a vanadium alloy membrane, a silica membrane, a zeolite membrane, or a polymer membrane. ２ can be selectively transmitted.

[0057] On the other hand, since the second film 23 is a TiN film, it is possible to obtain hydrogen gas H 2 in a lower temperature environment than with a palladium film. ２ Furthermore, since the second membrane 23 is a TiN membrane, it can selectively pass hydrogen gas H 2 through the second membrane 23 more easily than a zeolite membrane or a polymer membrane. ２ The separation performance can be improved.

[0058] In the example of FIG. 5, the separated portion 22 may be a layer that is in contact with the second film 23 on the side opposite to the side of the second film 23 that is in contact with the hydrogen permeation layer 21 .

[0059] In the example of Figure 5, as shown in Figure 4, the first film 21b is located on each of the surfaces P1a of the multiple crystal grains P1 in the hydrogen permeation layer 21, thereby increasing the area of ​​the first film 21b having hydrogen separation function.

[0060] In the example of FIG. 5, the second membrane 23 having a hydrogen separation function is located above the hydrogen permeation layer 21, so that hydrogen gas H ２ Therefore, according to the example of FIG. 5, the hydrogen gas H ２ The separation performance can be improved.

[0061] 5, the second film 23 may be denser than the first film 21b (see FIG. 4). ２ Therefore, according to the example of FIG. 5, the hydrogen gas H ２ The separation performance can be improved.

[0062] 5, the thickness of the second film 23 on the first end 10c (see FIG. 1) side of the substrate 10 may be greater than the thickness of the second film 23 on the second end 10d (see FIG. 1) side of the substrate 10. The thickness of the second film 23 on the first end 10c side may be the average thickness of the second film 23 in a region from the inlet to L / 3. The thickness of the second film 23 on the second end 10d side may be the average thickness of the second film 23 in a region from the outlet to L / 3.

[0063] In this way, by making the thickness of the second membrane 23 smaller on the second end 10d side, which is the outlet side of the mixed gas G, than on the first end 10c side, which is the inlet side, the pressure of the mixed gas G is smaller than on the inlet side, and the hydrogen gas H ２ The separation performance can be improved.

[0064] Therefore, according to the example of FIG. 5, the hydrogen gas H ２ Therefore, the separation performance can be maintained well.

[0065] 5, the second film 23 may be formed by CVD. In this case, the second film 23 may be formed by, for example, TiCl ４ And, H ２ And, N ２ or NH ３ The film may be formed using the above as a source gas. This allows a high-quality TiN film to be formed.

[0066] Other embodiments will now be described with reference to Fig. 6 to Fig. 8. Fig. 6 is a cross-sectional view showing an example of the configuration of a hydrogen separation member 1 according to another embodiment 1, and corresponds to Fig. 1 of the embodiment.

[0067] As shown in Fig. 6, in another embodiment 1, the position of the hydrogen separation membrane 20 differs from that of the above-described embodiment. Specifically, in another embodiment 1, the hydrogen separation membrane 20 may be located on the outer peripheral surface 10b of the substrate 10. In the example of Fig. 6, the outer peripheral surface 10b is an example of the surface.

[0068] This also allows the area of ​​the first film 21b having hydrogen separation function to be increased by positioning the first film 21b on each of the surfaces P1a of the multiple crystal grains P1 in the hydrogen permeation layer 21, as shown in Figure 4.

[0069] In the example of FIG. 6, hydrogen gas H ２ The mixed gas G containing the hydrogen gas may be flowed along the outer peripheral surface 10b of the substrate 10 from the first end 10c to the second end 10d. Then, the hydrogen gas H separated from the mixed gas G by the hydrogen separating member 1 is ２ may be collected from the inner peripheral surface 10 a of the substrate 10 .

[0070] FIG. 7 is a cross-sectional view showing an example of the configuration of a hydrogen separating member 1 according to another embodiment 2, and corresponds to FIG. 2 of the embodiment.

[0071] As shown in Fig. 7 , in Alternative Embodiment 2, the configuration of the through holes S differs from that of the above-described embodiments. Specifically, in Alternative Embodiment 2, the substrate 10 may have a plurality of through holes S. A hydrogen separation membrane 20 (see Fig. 2 ) may be located on each of a plurality of inner circumferential surfaces 10a located in each through hole S.

[0072] This also allows the area of ​​the first film 21b having hydrogen separation function to be increased by positioning the first film 21b on each of the surfaces P1a of the multiple crystal grains P1 in the hydrogen permeation layer 21, as shown in Figure 4.

[0073] In addition, in the second embodiment, the area of ​​the inner peripheral surface 10a of the substrate 10 can be increased, and therefore the area of ​​the hydrogen separation membrane 20 can be increased. ２ (See FIG. 1) can improve the separation performance.

[0074] In the example of FIG. 7, hydrogen gas H ２ The mixed gas G (see FIG. 1) containing hydrogen may flow through the plurality of through holes S from the first end 10c (see FIG. 1) to the second end 10d (see FIG. 1). Then, the hydrogen gas H separated from the mixed gas G by the hydrogen separating member 1 is ２ may be collected from the outer peripheral surface 10b of the substrate 10.

[0075] Fig. 8 is a perspective view showing an example of the configuration of a hydrogen separation member 1 according to Alternative Embodiment 3. As shown in Fig. 8, Alternative Embodiment 3 differs from the above-described embodiments in the configuration of the substrate 10. Specifically, in Alternative Embodiment 3, the substrate 10 may be flat rather than cylindrical.

[0076] 8, the substrate 10 may be, for example, a rectangular flat plate. Also, for example, the hydrogen separation membrane 20 may be located on one surface 10e of the substrate 10.

[0077] This also allows the area of ​​the first film 21b having hydrogen separation function to be increased by positioning the first film 21b on each of the surfaces P1a of the multiple crystal grains P1 in the hydrogen permeation layer 21, as shown in Figure 4.

[0078] 8, a hydrogen separation membrane 20 may be located on each of a plurality of substrates 10, and the substrates 10 may be arranged in parallel. This allows the hydrogen separation process to be performed in multiple stages, and the hydrogen gas H ２ The separation performance can be improved.

[0079] Although the present disclosure has been described in detail above, the present disclosure is not limited to the above-described embodiments, and various modifications, improvements, etc. are possible within the scope of the gist of the present disclosure. For example, in the examples of Figures 1 to 6 above, a cylindrical substrate 10 is shown as an example of a cylindrical substrate 10, but the present disclosure is not limited to such an example, and the substrate 10 may be a polygonal cylindrical shape, etc.

[0080] The disclosed embodiments should be considered in all respects as illustrative and not restrictive. Indeed, the above-described embodiments may be embodied in various forms. Furthermore, the above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims.

[0081] The present technology may have the following configurations: (1) A hydrogen separation member comprising: a substrate having a plurality of crystal grains; and a first film containing Ti and N, the first film being positioned so as to cover at least one of the plurality of crystal grains. (2) The hydrogen separation member according to (1), further comprising: a hydrogen permeation layer positioned on at least a portion of the surface of the substrate, the hydrogen permeation layer being composed of an aggregate of a plurality of coated particles, the aggregate having the plurality of crystal grains and the first film. (3) The hydrogen separation member according to (1) or (2), wherein the thickness of the first film at a position close to the surface of the substrate is greater than the thickness of the first film at a position farther from the surface of the substrate. (4) The hydrogen separation member according to any one of (1) to (3), wherein the size of the plurality of crystal grains at a position farther from the surface of the substrate is greater than the size of the plurality of crystal grains at a position close to the surface of the substrate. (5) The hydrogen separation member according to (2), wherein the plurality of coated particles include a first coated particle and a second coated particle adjacent to the first coated particle, and the first film of the second coated particle is continuous with the first film of the first coated particle. (6) The hydrogen separator according to (5), wherein the second coated particles are adjacent to the first coated particles in a planar direction. (7) The hydrogen separator according to (5) or (6), wherein the second coated particles are adjacent to the first coated particles in a depth direction. (8) The hydrogen separator according to any one of (2), (5) to (7), further comprising a second membrane located above the hydrogen permeation layer, containing Ti and N, and being denser than the first membrane.

[0082] REFERENCE SIGNS LIST 1 Hydrogen separation member 10 Substrate 10a Inner peripheral surface (example of surface) 10b Outer peripheral surface (example of surface) 20 Hydrogen separation membrane 21 Hydrogen permeation layer 21a Coated particle 21a1 First coated particle 21a2 Second coated particle 21b First film 22 Separation portion 23 Second film D1 Surface direction D2 Depth direction G Mixed gas H2 Hydrogen gas P1 Crystal grain

Claims

1. A hydrogen separation element comprising: a substrate having a plurality of crystal grains; and a first membrane containing Ti and N and positioned so as to cover at least one of the plurality of crystal grains.

2. The hydrogen separation member according to claim 1, further comprising a hydrogen permeation layer located on at least a portion of the surface of the substrate and composed of an aggregate of a plurality of coated particles having the plurality of crystal grains and the first film.

3. The hydrogen separation element according to claim 1 or 2, wherein the thickness of the first film at a position close to the surface of the substrate is greater than the thickness of the first film at a position farther from the surface of the substrate.

4. A hydrogen separation member according to any one of claims 1 to 3, wherein the size of the plurality of crystal grains at positions farther from the surface of the substrate is larger than the size of the plurality of crystal grains at positions closer to the surface of the substrate.

5. The hydrogen separation element according to claim 2, wherein the plurality of coated particles include a first coated particle and a second coated particle adjacent to the first coated particle, and the first film of the second coated particle is continuous with the first film of the first coated particle.

6. The hydrogen separating element according to claim 5, wherein the second coated particles are adjacent to the first coated particles in the planar direction.

7. The hydrogen separating element according to claim 5, wherein the second coated particles are adjacent to the first coated particles in the depth direction.

8. The hydrogen separating element according to any one of claims 2 and 5 to 7, further comprising a second membrane located above the hydrogen permeation layer, containing Ti and N, and being denser than the first membrane.

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