Hydrogen separation member

Abstract

This hydrogen separation member comprises a base material, a first membrane, and a black part. The first membrane covers at least a part of the base material and includes Ti and N. The black part is positioned between the base material and the first membrane.

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 member of the present disclosure includes a substrate, a first membrane, and a black portion. The first membrane covers at least a portion of the substrate and contains Ti and N. The black portion is located between the substrate and the first membrane.

[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 first crystal grains and black portions according to an embodiment. FIG. 5 is an enlarged cross-sectional view showing an example of the configuration of second crystal grains and black portions according to an embodiment. FIG. 6 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. 7 is a cross-sectional view showing an example of the configuration of a hydrogen separation member according to another embodiment 1. FIG. 8 is a cross-sectional view showing an example of the configuration of a hydrogen separation member according to another embodiment 2. FIG. 9 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 techniques have room for further improvement in terms of increasing the adhesion of the hydrogen separation membrane.

[0010] <Configuration of Hydrogen Separator> First, the configuration of the hydrogen separator 1 according to the embodiment will be described with reference to Fig. 1 to Fig. 6. Fig. 1 is a cross-sectional view showing an example of the configuration of the hydrogen separator 1 according to the embodiment. Fig. 2 is a cross-sectional view taken along the line A-A in Fig. 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.

[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 opposite to the first end 10c. The first end 10c is an example of one end, and the second end 10d is an example of the other end. 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] Fig. 3 is an enlarged cross-sectional view showing an example of the configuration of the hydrogen separation membrane 20 according to the embodiment and its surroundings, 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 an intermediate layer 21, a first membrane 22, and a separation portion 23.

[0017] The intermediate layer 21 may be a layer in contact with the inner peripheral surface 10a of the substrate 10. The material of the intermediate layer 21 is a material that can be used for hydrogen gas H ２ (See Figure 1) ２ O ３ It may also be ceramics such as those mentioned above.

[0018] The intermediate layer 21 may have, for example, a polycrystalline structure. ２ Because there are many grain boundaries through which hydrogen gas H ２ can be smoothly transmitted.

[0019] The intermediate layer 21 may have a finer polycrystalline structure than the substrate 10. In other words, the average grain size of the second crystal grains P2 (see FIG. 5) constituting the intermediate layer 21 may be smaller than the average grain size of the first crystal grains P1 (see FIG. 4) constituting the substrate 10 (see FIG. 1). The intermediate layer 21 may have an average pore size or porosity smaller than that of the substrate 10.

[0020] This makes the film formation surface flatter than when the first film 22 is formed directly on the inner circumferential surface 10a of the substrate 10, and therefore the first film 22 can be formed satisfactorily.

[0021] For example, the first crystal grains P1 constituting the base material 10 may have an average grain size of about 0.5 μm, and the second crystal grains P2 constituting the intermediate layer 21 may have an average grain size of 100 nm or less.

[0022] The intermediate layer 21 may have the same composition as the substrate 10. The material of the intermediate layer 21 and the material of the substrate 10 may have the same composition but different crystal phases. In the embodiment, for example, the substrate 10 may be made of α-phase Al. ２ O ３ The intermediate layer 21 may be Al in the γ phase. ２ O ３ As a result, the intermediate layer 21 has a finer polycrystalline structure than the substrate 10.

[0023] The first film 22 may be a layer that is in contact with the intermediate layer 21 on the side opposite to the side of the intermediate layer 21 that is in contact with the substrate 10. The first film 22 is a layer that is in contact with hydrogen gas H ２ selectively permeates hydrogen gas H ２ The first membrane 22 may have a property of being difficult to permeate gases other than hydrogen gas H ２ Other gases may not be allowed to permeate.

[0024] The first film 22 may contain, for example, Ti (titanium) and N (nitrogen), or may be a TiN (titanium nitride) film. When the first film 22 has a TiN crystal structure, hydrogen is converted into hydride ions (H － ) and diffuses through the grain boundaries, while other gas constituent elements are less likely to permeate. ２ can be selectively transmitted.

[0025] In the present disclosure, the first film 22 is not limited to a TiN film, and may be a hydrogen gas H ２Alternatively, the hydrogen separation membrane 20 including the first membrane 22 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.

[0026] On the other hand, since the first film 22 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 first membrane 22 is a TiN membrane, it can selectively pass hydrogen gas H 2 through the first membrane 22 more easily than a zeolite membrane or a polymer membrane. ２ The separation performance can be improved.

[0027] The separated portion 23 may be a layer in contact with the first film 22 on the side opposite to the side of the first film 22 in contact with the intermediate layer 21. The separated portion 23 may be formed, for example, by converting hydrogen gas H 2 contained in the mixed gas G into hydrogen gas H 3 by a chemical reaction shown in the following formula (1): ２ may have the property of converting H to a hydride ion. ２ + 2e － → 2H － ...(1)

[0028] The separation portion 23 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 23 may also contain oxides of these elements. This allows hydrogen gas H ２ can be efficiently converted into a hydride ion.

[0029] When the first membrane 22 is formed of a membrane other than a TiN membrane, the separation portion 23 may be omitted from the hydrogen separation membrane 20. The separation portion 23 may be located between the first membrane 22 and the substrate 10. The separation portion 23 may be located so as to sandwich the first membrane 22.

[0030] 3, the hydrogen separation member 1 may have a black portion 30 located between the substrate 10 and the first membrane 22. The black portion 30 may be composed of at least one of an incomplete oxide of Ti, an incomplete oxide of Al, or a combination of Ti, Al, and oxygen, for example.

[0031] The black portion 30 may be positioned so as to cover the surface P1a of the first crystal grain P1 constituting the base material 10, as shown in FIG. 4, or may be positioned so as to cover the surface P2a of the second crystal grain P2 constituting the intermediate layer 21, as shown in FIG.

[0032] In this embodiment, the hydrogen separating member 1 has the black portion 30, which can improve the adhesion between the first membrane 22 having a hydrogen separating function and the substrate 10.

[0033] In addition, in the embodiment, the black portion 30 may be located from the first film 22 to the inside of the substrate 10. For example, the black portion 30 may be located between the interface 24 between the intermediate layer 21 and the first film 22 and a region 31 located inside the substrate 10. This can improve the adhesion between the first film 22 and the substrate 10.

[0034] In addition, in the embodiment, the hydrogen separation membrane 20 may be located on the inner peripheral surface 10a of the cylindrical substrate 10. That is, in the embodiment, the first membrane 22 included in the hydrogen separation membrane 20 and the black portion 30 located inside and near the hydrogen separation membrane 20 may be located on the inner peripheral surface 10a of the cylindrical substrate 10.

[0035] In this way, the hydrogen separation membrane 20 having a hydrogen separation function is positioned 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 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.

[0036] 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.

[0037] In addition, in an embodiment, the depth of the black portion 30 on the first end 10c (see FIG. 1) side of the substrate 10 may be deeper than the depth of the black portion 30 on the second end 10d (see FIG. 1) side of the substrate 10. In this disclosure, the "depth of the black portion 30" refers to the distance between the exposed surface 20a of the hydrogen separation membrane 20 and a region 31 that is the deepest part of the black portion 30.

[0038] 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 "depth of the black portion 30" on the first end 10c side may be defined as the average value of the distance between the exposed surface 20a of the hydrogen separation membrane 20 in the region from the inlet to L / 3 and the region 31, which is the deepest part of the black portion 30, i.e., the average depth. The "depth of the black portion 30" on the second end 10d side may be defined as the average value of the distance between the exposed surface 20a of the hydrogen separation membrane 20 in the region from the outlet to L / 3 and the region 31, which is the deepest part of the black portion 30, i.e., the average depth.

[0039] In this way, by making the depth of the black portion 30 deeper at the first end 10c, which is the inlet side of the mixed gas G, than at the second end 10d, which is the outlet side, the adhesion of the first film 22 at the inlet side, where the pressure of the mixed gas G is greater than at the outlet side, can be further improved.

[0040] Therefore, according to the embodiment, the adhesion of the first film 22 can be maintained well over the entire area of ​​the inner circumferential surface 10a from the inlet side to the outlet side.

[0041] In addition, in the embodiment, the thickness of the first film 22 on the first end 10c side of the substrate 10 may be greater than the thickness of the first film 22 on the second end 10d side of the substrate 10. For example, the thickness of the first film 22 on the first end 10c side may be the average thickness of the first film 22 in a region from the inlet to L / 3. The thickness of the first film 22 on the second end 10d side may be the average thickness of the first film 22 in a region from the outlet to L / 3.

[0042] In this way, by making the thickness of the first membrane 22 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 lower than on the inlet side, and the hydrogen gas H ２ The separation performance can be improved.

[0043] Therefore, according to the embodiment, the hydrogen gas H ２ Therefore, the separation performance can be maintained well.

[0044] In addition, in an embodiment, the thickness of the black portion 30 on the first end 10c side of the substrate 10 may be greater than the thickness of the black portion 30 on the second end 10d side of the substrate 10. In the present disclosure, the "thickness of the black portion 30" refers to the distance between the surface P1a of the first crystal grain P1 or the surface P2a of the second crystal grain P2 and the outermost surface 30a of the black portion 30, as shown in Figures 4 and 5 .

[0045] For example, the thickness of the black portion 30 on the first end 10c side may be the average value of the distance between the surface P1a or the surface P2a in the region from the entrance to L / 3 and the outermost surface 30a of the black portion 30, i.e., the average thickness. The thickness of the black portion 30 on the second end 10d side may be the average value of the distance between the surface P1a or the surface P2a in the region from the exit to L / 3 and the outermost surface 30a of the black portion 30, i.e., the average thickness.

[0046] In this way, by making the thickness of the black portion 30 greater at the first end 10c, which is the inlet side of the mixed gas G, than at the second end 10d, which is the outlet side, the adhesion of the first film 22 can be further improved at the inlet side where the pressure of the mixed gas G is greater than at the outlet side.

[0047] Therefore, according to the embodiment, the adhesion of the first film 22 can be maintained well over the entire area of ​​the inner circumferential surface 10a from the inlet side to the outlet side.

[0048] In the embodiment, TiN crystals may be formed in a columnar shape in the first film 22. This allows the crystal grain boundaries of TiN to be positioned so as to connect the separation portion 23 and the intermediate layer 21, which allows smooth diffusion of hydride ions in the first film 22. Therefore, according to the embodiment, hydrogen gas H ２ The separation performance can be improved.

[0049] In the embodiment, the first film 22 may be formed by chemical vapor deposition (CVD). In this case, the first film 22 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.

[0050] In the embodiment described so far, an example has been shown in which the hydrogen separation membrane 20 is composed of the intermediate layer 21, the first membrane 22, and the separation portion 23, but the present disclosure is not limited to such an example. Fig. 6 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.

[0051] 6, the hydrogen separation membrane 20 may be composed of a first membrane 22 and a separation portion 23. In this case, the black portion 30 is located between the substrate 10 and the first membrane 22, thereby improving the adhesion between the substrate 10 and the first membrane 22, which has a hydrogen separation function.

[0052] For example, in the example of FIG. 6 , the black portion 30 may be located between the inner circumferential surface 10 a of the substrate 10 and a region 31 located inside the substrate 10 .

[0053] Other embodiments will now be described with reference to Fig. 7 to Fig. 9. Fig. 7 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.

[0054] 7, 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.

[0055] This also allows the black portion 30 to be positioned between the substrate 10 and the first membrane 22, as shown in Figures 3 and 6, thereby improving the adhesion between the substrate 10 and the first membrane 22, which has a hydrogen separation function.

[0056] In the example of FIG. 7, 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 .

[0057] FIG. 8 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.

[0058] As shown in Fig. 8, 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.

[0059] This also allows the black portion 30 to be positioned between the substrate 10 and the first membrane 22, as shown in Figures 3 and 6, thereby improving the adhesion between the substrate 10 and the first membrane 22, which has a hydrogen separation function.

[0060] 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.

[0061] In the example of FIG. 8, hydrogen gas H ２The 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.

[0062] Fig. 9 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. 9, 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.

[0063] 9, 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.

[0064] This also allows the black portion 30 to be positioned between the substrate 10 and the first membrane 22, as shown in Figures 3 and 6, thereby improving the adhesion between the substrate 10 and the first membrane 22, which has a hydrogen separation function.

[0065] 9, 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.

[0066] 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 7 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.

[0067] 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.

[0068] The present technology may have the following configurations. (1) A hydrogen separation member comprising: a substrate; a first membrane covering at least a portion of the substrate and containing Ti and N; and a black portion located between the substrate and the first membrane. (2) The hydrogen separation member according to (1), wherein the black portion is located from the first membrane to the interior of the substrate. (3) The hydrogen separation member according to (1) or (2), wherein the substrate has a cylindrical shape, and the first membrane and the black portion are located on the inner circumferential surface or the outer circumferential surface of the substrate. (4) The hydrogen separation member according to (3), wherein the depth of the black portion at one end of the substrate is deeper than the depth of the black portion at the other end of the substrate. (5) The hydrogen separation member according to (3) or (4), wherein the thickness of the first membrane at one end of the substrate is greater than the thickness of the first membrane at the other end of the substrate. (6) The hydrogen separation member according to any one of (1) to (5), further comprising an intermediate layer between the substrate and the first membrane, wherein the average grain size of the second crystal grains constituting the intermediate layer is smaller than the average grain size of the first crystal grains constituting the substrate. (7) The hydrogen separation member according to any one of (3) to (5), further comprising: a black portion positioned to cover surfaces of the first crystal grains constituting the substrate and the second crystal grains constituting the intermediate layer located between the substrate and the first membrane; and a thickness of the black portion positioned on the surfaces of the first crystal grains and the second crystal grains at one end of the substrate is greater than a thickness of the black portion positioned on the surfaces of the first crystal grains and the second crystal grains at the other end of the substrate.

[0069] REFERENCE SIGNS LIST 1 Hydrogen separation member 10 Substrate 10a Inner peripheral surface 10b Outer peripheral surface 10c First end (an example of one end) 10d Second end (an example of the other end) 20 Hydrogen separation membrane 21 Intermediate layer 22 First membrane 30 Black portion G Mixed gas H2 Hydrogen gas P1 First crystal grain P1a Surface P2 Second crystal grain P2a Surface

Claims

1. A hydrogen separation member comprising: a substrate; a first membrane covering at least a portion of the substrate and containing Ti and N; and a black portion located between the substrate and the first membrane.

2. The hydrogen separation element according to claim 1, wherein the black portion is located from the first membrane to the interior of the substrate.

3. A hydrogen separation member according to claim 1 or 2, wherein the substrate has a cylindrical shape, and the first membrane and the black portion are located on the inner or outer peripheral surface of the substrate.

4. The hydrogen separating element according to claim 3, wherein the depth of the black portion at one end of the substrate is greater than the depth of the black portion at the other end of the substrate.

5. The hydrogen separation element according to claim 3 or 4, wherein the thickness of the first membrane at one end of the substrate is greater than the thickness of the first membrane at the other end of the substrate.

6. A hydrogen separation element according to any one of claims 1 to 5, which has an intermediate layer between the substrate and the first membrane, and the average grain size of the second crystal grains constituting the intermediate layer is smaller than the average grain size of the first crystal grains constituting the substrate.

7. A hydrogen separation member according to any one of claims 3 to 5, wherein the black portion is positioned so as to cover the surfaces of first crystal grains constituting the substrate and second crystal grains constituting an intermediate layer located between the substrate and the first membrane, and the thickness of the black portion located on the surfaces of the first crystal grains and the second crystal grains at one end of the substrate is greater than the thickness of the black portion located on the surfaces of the first crystal grains and the second crystal grains at the other end of the substrate.

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