JP2008253932A - Hydrogen purification filter and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydrogen purification filter which shows excellent hydrogen permeation efficiency in hydrogen purification, and to provide a manufacturing method for easily manufacturing the filter. <P>SOLUTION: The hydrogen purification filter comprises a front Pd alloy membrane arranged on one surface of a porous support having a plurality of pores so as to cover the pores, a diffusion preventing layer existing between the front Pd alloy membrane and the porous support, and a back Pd alloy membrane arranged on the other surface of the porous support including the internal wall surfaces of the pores and on the front Pd alloy membrane located in the pores. A laminated portion of the front Pd alloy membrane and the back Pd alloy membrane located in the pores serves as a hydrogen-permeable membrane. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a hydrogen purification filter and a method for producing the same, and more particularly to a hydrogen purification filter used in a reformer or the like for steam reforming various hydrocarbon fuels to produce a hydrogen rich gas, The present invention relates to a manufacturing method that can be manufactured.

In recent years, global environmental and energy / resource problems have become apparent, and fuel cells have been attracting attention as one of energy supply systems that harmonize these with industry. A fuel cell directly produces hydrogen gas or hydrogen-rich gas obtained by reforming a hydrocarbon-based fuel such as natural gas, gasoline, butane gas, or methanol by electrochemical reaction with oxygen in the air. It is the electric power generating apparatus which takes out. The fuel cell using the hydrogen-rich gas includes a reformer that generates hydrogen-rich gas by steam reforming a hydrocarbon-based fuel, a fuel cell body that generates electricity, a converter that converts the generated DC electricity into AC, and the like It consists of
Such a fuel cell may be a phosphoric acid fuel cell (PAFC), a molten carbonate fuel cell (MCFC), a solid electrolyte fuel cell (SOFC), an alkaline type, depending on the electrolyte used in the fuel cell body, the reaction form, etc. There are five types of fuel cells (AFC) and polymer electrolyte fuel cells (PEFC). Among these, the polymer electrolyte fuel cell (PEFC) is advantageous in that the electrolyte is solid compared to other fuel cells such as a phosphoric acid fuel cell (PAFC) and an alkaline fuel cell (AFC). Have the requirements.

However, the polymer electrolyte fuel cell (PEFC) uses platinum as the catalyst and has a low operating temperature, so that the electrode catalyst is poisoned by a small amount of CO, and the performance deterioration is particularly remarkable in a high current density region. There is. For this reason, it is necessary to reduce the CO concentration contained in the reformed gas (hydrogen-rich gas) generated by the reformer to about 10 ppm.
As one of the means for purifying hydrogen by removing CO from the reformed gas, a hydrogen purification filter having a Pd alloy film has been developed. In particular, only hydrogen is permeable, and the reformed gas side is set to a high temperature and high pressure (for example, 500 ° C., 3 to 10 kg / cm ² (0.29 to 0.98 MPa)), thereby achieving a low hydrogen partial pressure side. Permeates hydrogen.

  In the hydrogen refining method using the Pd alloy film as described above, the hydrogen permeation rate is inversely proportional to the film thickness, so that a thin film is required. However, from the viewpoint of mechanical strength, the Pd alloy film alone is about 30 μm. In the case of using a Pd alloy film having a film thickness of about several tens of μm, a porous support was disposed on the low hydrogen partial pressure side of the Pd alloy film. However, since the Pd alloy film and the support are separately mounted on the reformer, the workability for obtaining good sealing is poor, and the Pd alloy film and the support are rubbed to cause the Pd alloy film. There was a problem that the durability of was not sufficient.

In order to solve the above problem, a hydrogen purification filter in which a Pd alloy film is directly formed on a support and the Pd alloy film and the support are integrated has been developed. For example, a Pd alloy film is formed on one side of a metal support, and pores are formed on the metal support by single-sided etching to form a first support, and through holes are previously formed on the Pd alloy film by etching. There is a hydrogen purification filter manufactured by laminating the second support formed (Patent Document 1). Also, a Pd alloy film is formed on the temporary support, a resist pattern is formed on the Pd alloy film, and then a metal base having a fine opening so as to cover 30 to 95% of the Pd alloy film. There is a hydrogen purification filter manufactured by forming a membrane by electrolytic plating and then removing the temporary support (Patent Document 2).
JP 7-124453 A JP 2002-292259 A

However, in the hydrogen purification filter of Patent Document 1 described above, since the pores are formed in the metal support (first support) by single-sided etching, the inner diameter of the formed pores is small on the Pd alloy film side, There was a problem that the hydrogen permeation efficiency was low. On the other hand, if the inner diameter of the pore is increased in order to increase the hydrogen permeation efficiency, the first support is likely to warp due to the residual stress during the formation of the Pd alloy film. Furthermore, for joining with the second support, a frame member is provided at the outer peripheral portion of the Pd alloy film, and a frame member is also provided at the outer periphery of the second support, and this frame member is welded and integrated. Therefore, the second support and the Pd alloy film are not joined, and the function of the second support as a support is not sufficiently exhibited, and there is a problem that the strength is low.
In addition, the hydrogen purification filter of Patent Document 2 described above has a problem that the Pd alloy film formed on the temporary support is weak in adhesion and easily peels off during the process. In addition, when the resist pattern is thin, the metal base film formed by electrolytic plating blocks the opening of the resist pattern. On the other hand, when the resist pattern is thick, the resist is formed in the fine opening of the formed metal base film. There was also a problem that it was easy to remain. Further, it takes a long time to form the metal base film on the Pd alloy film by electrolytic plating, and there is a problem that it is difficult to form a metal base film having a sufficient strength and a large thickness.

Further, the conventional hydrogen purification filter has a problem that warp is likely to occur and handling properties are poor.
This invention is made | formed in view of the above situations, and provides the hydrogen purification filter which shows the hydrogen permeation efficiency excellent in hydrogen purification, and the manufacturing method for manufacturing such a filter simply. Objective.

  In order to achieve such an object, a hydrogen purification filter of the present invention includes a porous support having a plurality of pores, and a front surface Pd disposed on one surface of the porous support so as to cover the pores. An alloy film, a diffusion preventing layer interposed between the front surface Pd alloy film and the porous support, the other surface of the porous support including the inner wall surface of the hole, and the front surface located in the hole A back Pd alloy film disposed on the Pd alloy film, and a layered portion of the front Pd alloy film and the back Pd alloy film located in the hole is a hydrogen permeable film.

As another aspect of the present invention, the total opening area of the holes occupies 20 to 90% of the area of the porous support.
As another aspect of the present invention, the porous support is configured to be stainless steel.
As another aspect of the present invention, the porous support has a thickness in the range of 10 to 100 μm, and the hydrogen permeable membrane has a thickness in the range of 1 to 13 μm.
As another aspect of the present invention, the diffusion prevention layer is configured to be a conductive thin film made of at least one of titanium nitride, titanium carbide, tantalum nitride, tantalum carbide, and chromium nitride.

  Further, in the method for producing a hydrogen purification filter of the present invention, a resist pattern having a plurality of openings is formed on both surfaces of a metal support, and the hole is formed by etching the metal support from the front and back using the resist pattern as a mask. An etching step for producing a porous support having a plurality of holes by drilling; a diffusion prevention layer forming step for forming a conductive diffusion prevention layer on one surface of the porous support; and the porous support. A metal plate that can be selectively etched with respect to the porous support is closely fixed to the surface provided with the diffusion preventing layer of the porous support, and the inner surface of the hole is included by electroplating from the other surface side of the porous support. A first electroplating step of forming a back Pd alloy film on the support and on the metal plate located in the hole, and the surface exposed by removing the metal plate by selective etching Forming a front Pd alloy film by Kki and a second electroplating step of the lamination portion between the rear Pd alloy film and the front surface Pd alloy film and the hydrogen-permeable membrane, and that have configure.

As another aspect of the present invention, the metal support is stainless steel, and the metal plate is copper or nickel.
As another aspect of the present invention, in the etching step, a plurality of holes are formed so that the total opening area of the holes occupies 20 to 90% of the area of the porous support. .
As another aspect of the present invention, in the diffusion preventing layer forming step, a diffusion preventing layer made of at least one of titanium nitride, titanium carbide, tantalum nitride, tantalum carbide, and chromium nitride is formed by a vacuum film forming method. It was.
As another aspect of the present invention, in the first electroplating step, the back surface Pd alloy film is formed to have a thickness in the range of 0.1 to 3 μm.
As another aspect of the present invention, in the second electroplating step, the front Pd alloy film is formed to have a thickness in the range of 1 to 10 μm.

In the hydrogen purification filter of the present invention, the laminated portion of the front Pd alloy film and the back Pd alloy film constitutes a hydrogen permeable film. Therefore, the hydrogen permeable film is thin and has no defects such as pinholes, It has high hydrogen permeation efficiency and excellent reliability, and has a front Pd alloy film on one side of the porous support and a back Pd alloy film on the other side, that is, both sides of the porous support. Are provided with a Pd-based thin film, the stress of these Pd-based films is offset and warpage is difficult to occur, and the handleability is excellent. Furthermore, the porous support, the front Pd alloy film, Since the diffusion preventing layer is interposed between them, the diffusion of the constituent material of the porous support to the front Pd alloy film is suppressed, and a high hydrogen permeability is maintained even when used for a long time at a high temperature.
In the method for producing a hydrogen purification filter of the present invention, a porous support is produced by forming a plurality of holes in a metal support by double-sided etching before forming a hydrogen permeable membrane. In addition, since the electroplating is performed from one surface of the porous support with the metal plate adhered and fixed to one surface of the porous support, the back surface Pd alloy film is reliably formed inside the hole. In addition, the metal plate is not peeled off during the process, the handling property is good, and the front Pd alloy film is formed by electroplating from the other surface of the porous support, Since the laminated part of the front Pd alloy film and the back Pd alloy film is a hydrogen permeable film, a thin hydrogen permeable film can be formed without defects such as pinholes, and the film formation stress is alleviated and warping is reduced. Generation can be reduced, Ring is good.

Embodiments of the present invention will be described below with reference to the drawings.
[Hydrogen purification filter]
FIG. 1 is a partial cross-sectional view showing an embodiment of the hydrogen purification filter of the present invention. In FIG. 1, a hydrogen purification filter 1 includes a porous support 2 having a plurality of fine pores 3, and a front surface Pd disposed so as to cover the pores 3 on one surface 2 a side of the porous support 2. An alloy film 5, a diffusion preventing layer 6 interposed between the front Pd alloy film 5 and the surface 2a of the porous support 2, the other surface 2b of the porous support 2 including the inner wall surface 3a of the hole 3, and And a back Pd alloy film 7 disposed on the front Pd alloy film 5 located in the hole 3. The back surface Pd alloy film 7 is laminated on the back surface Pd alloy film 7 a located on the surface 2 b of the porous support 2, the back surface Pd alloy film 7 b located on the inner wall surface 3 a of the hole 3, and the front surface Pd alloy film 5. The back Pd alloy film 7c is positioned so as to be The laminated portion of the front Pd alloy film 5 and the back Pd alloy film 7 c located in the hole 3 is a hydrogen permeable film 4. In the present invention, the front Pd alloy film 5 and the back Pd alloy film 7 include those whose material is only Pd.

The porous support 2 constituting the hydrogen purification filter 1 can be produced using a material having electrical conductivity such as austenitic, ferritic stainless steel, copper, nickel such as SUS304 and SUS430, and has a thickness of 10 It can be suitably set within a range of -100 μm, preferably 20-50 μm.
The pores 3 of the porous support 2 can have an opening diameter of 20 to 500 μm, preferably 30 to 200 μm. Moreover, the total area of the opening of the hole 3 can be set so as to occupy 20 to 90%, preferably 40 to 80% of the area of the porous support 2. The opening of the hole 3 means an opening in a region where the hydrogen permeable film 4 is formed.
As described above, the hydrogen permeable membrane 4 constituting the hydrogen purification filter 1 is composed of the laminated portion of the front Pd alloy film 5 and the rear Pd alloy film 7c located in the hole 3.

The front Pd alloy film 5 and the back Pd alloy film 7 are thin films having a Pd content of 60% by weight or more, and include those whose material is only Pd as described above. When the front Pd alloy film 5 or the back Pd alloy film 7 is a Pd alloy, it contains one or more of Ag, Cu, Pt, Au, Ni, Co, V, Nb, Ta, Zr, etc. as additive elements It may be. The thickness of the hydrogen permeable membrane 4 is preferably as thin as possible from the viewpoint of improving the hydrogen permeation rate, but can be appropriately set within a range of, for example, 1 to 13 μm, preferably 2 to 6 μm. The material of the front Pd alloy film 5 and the back Pd alloy film 7 may be the same or different.
The thickness of the front Pd alloy film 5 constituting the hydrogen permeable film 4 can be set in the range of, for example, 1 to 10 μm, preferably 2 to 5 μm. Moreover, the thickness of the back surface Pd alloy film 7c which comprises the hydrogen permeable film 4 can be set, for example in the range of 0.1-3 micrometers, Preferably it is 0.1-1 micrometer.

  The diffusion preventing layer 6 constituting the hydrogen purification filter 1 prevents the constituent material of the porous support 2 from diffusing into the front Pd alloy film 5 and further into the hydrogen permeable film 4, and the porous support 2. And a front Pd alloy film 5 for ensuring high adhesion. Such a diffusion preventing layer 6 has conductivity made of nitride, oxide or carbide of one or more elements selected from Ti, Ta, Si, Al, Mg, Ce, Cr, Ca, Zr and the like. The thin film may be a thin film such as titanium nitride (TiN), titanium carbide (TiC), tantalum nitride (TaN), tantalum carbide (TaC), or chromium nitride (CrN). Further, the diffusion preventing layer 6 may be a thin film having hydrogen permeability made of a refractory metal such as Zr, Mo, Ta, W, Cr, Hf, Nb, or Ru. The thickness of the diffusion preventing layer 6 can be set as appropriate, and can be, for example, about 0.01 to 5 μm, preferably about 0.5 to 2 μm.

In such a hydrogen purification filter 1, the laminated portion of the front Pd alloy film 5 and the back Pd alloy film 7 c constitutes the hydrogen permeable film 4, so that the hydrogen permeable film 4 is thin and has defects such as pinholes. It has no hydrogen permeability and high reliability. Further, since the front surface Pd alloy film 5 is provided on one surface of the porous support 2 and the back surface Pd alloy film 7 is provided on the other surface, warpage hardly occurs and the handling property is excellent. Furthermore, since the diffusion preventing layer 6 is interposed between the porous support 2 and the front Pd alloy film 5, the diffusion of the constituent material of the porous support 2 into the front Pd alloy film 5 is suppressed, and it is possible to prevent the diffusion at a high temperature. High hydrogen permeability is maintained over time.
In addition, the above-mentioned embodiment is an illustration and the hydrogen purification filter of this invention is not limited to these.

[Method for producing hydrogen purification filter]
Next, the manufacturing method of the hydrogen purification filter of this invention is demonstrated.
2 and 3 are process diagrams showing an embodiment of the method for producing a hydrogen purification filter of the present invention, using the hydrogen purification filter 1 of the present invention as an example.
In the manufacturing method according to the present invention, first, in an etching process, a resist pattern 9 having a plurality of openings 9a is formed on both surfaces of a metal support 8 (FIG. 2A), and the resist patterns 9 and 9 are used as a mask. The metal support 8 is etched from the front and back sides to form the hole 3 (FIG. 2B). Thereby, the porous support body 2 which has the some hole part 3 is produced. As the metal support 8, for example, the porous support 2 can be made of austenitic or ferritic stainless steel such as SUS304 or SUS430, copper, nickel, or the like. The thickness of the metal support 8 can be set in the range of, for example, 10 to 100 μm, preferably 20 to 50 μm.

Etching for forming the hole 3 can be performed by conventionally known etching such as a spray method, a dipping method, or a spraying method. In this etching step, it is preferable to drill a plurality of holes 3 such that the total opening area of the holes 3 occupies 20 to 90%, preferably 40 to 80% of the area of the porous support 2. The opening diameter of each hole 3 to be drilled can be appropriately set within a range of, for example, 20 to 500 μm, preferably 30 to 200 μm.
Next, in the diffusion preventing layer forming step, a conductive diffusion preventing layer 6 is formed on one surface 2a of the porous support 2 (FIG. 2C). Formation of the diffusion preventing layer 6 can be performed by providing a resist pattern at a non-formation site, or by a vacuum film forming method such as vacuum deposition, ion plating, or sputtering through a desired mask. Alternatively, the diffusion preventing layer 6 can be formed by electroless plating by applying a catalyst to a desired site. Specifically, it can be formed as a thin film of nitride, oxide or carbide of one or more elements selected from Ti, Ta, Si, Al, Mg, Ce, Cr, Ca, Zr, etc. Examples thereof include thin films such as titanium nitride (TiN), titanium carbide (TiC), tantalum nitride (TaN), tantalum carbide (TaC), and chromium nitride (CrN). The diffusion prevention layer 6 can also be formed as a thin film of a refractory metal such as Zr, Mo, Ta, W, Cr, Hf, Nb, Ru. The thickness of the diffusion preventing layer 6 can be appropriately set within a range of 0.01 to 5 μm, preferably 0.5 to 2 μm, for example.

  Next, in the first electroplating step, the metal plate 10 is tightly fixed to the surface 2a side of the porous support 2 on which the diffusion prevention layer 6 is formed (FIG. 2D), and the other of the porous support 2 is fixed. A back Pd alloy film 7 is formed on the porous support 2 including the inner wall surface 3a of the hole 3 and the portion 10 'located in the hole 3 of the metal plate 10 by electroplating from the surface 2b side ( FIG. 3 (A)). The metal plate 10 to be used is made of a material that can be selectively etched with respect to the porous support 2. For example, when the porous support 2 is austenitic or ferritic stainless steel such as SUS304 or SUS430. , Copper, nickel, etc. In addition, the close contact between the porous support 2 and the metal plate 10 can be performed using, for example, a frame, a magnet, a clip, or the like.

The back Pd alloy film 7 thus formed includes a back Pd alloy film 7a located on the surface 2b of the porous support 2, a back Pd alloy film 7b located on the inner wall surface 3a of the hole 3, and a front Pd alloy film. 5 is composed of a back surface Pd alloy film 7c positioned so as to be laminated to the surface. In the first electroplating step, it is preferable to form the back surface Pd alloy film 7 so that its thickness is in the range of 0.1 to 3 μm, preferably 0.1 to 1 μm.
Next, in the second electroplating step, the metal plate 10 is removed by selective etching (FIG. 3B), and the exposed surface (the diffusion preventing layer 6 and the hole 3 positioned on the surface 2a of the porous support) is removed. The surface Pd alloy film 5 is formed by depositing Pd or a Pd alloy by electroplating on the back surface Pd alloy film 7c located on the surface (FIG. 3C). As a result, of the formed front Pd alloy film 5, the hydrogen permeable film 4 is used as a layered portion with the back Pd alloy film 7 c already formed in the hole 3, and the hydrogen purification filter 1 of the present invention is obtained. .

In the second electroplating step, it is preferable to form the front Pd alloy film 5 so that its thickness is in the range of 1 to 10 μm, preferably 2 to 5 μm.
In such a method for producing a hydrogen purification filter of the present invention, the porous support 2 is produced by drilling a plurality of holes 3 in the metal support 8 by double-sided etching before the hydrogen permeable membrane 4 is formed. A porous support 2 having an aperture ratio can be obtained. Further, since electroplating is performed from the other surface 2b side of the porous support 2 in a state where the metal plate 10 is tightly fixed to the one surface 2a of the porous support 2 provided with the diffusion preventing layer 6, the inside of the hole 3 is formed. Also, the back Pd alloy film 7 can be reliably formed. In addition, since the metal plate 10 and the porous support 2 are tightly fixed, the peeling of the metal plate 10 during the process is prevented, and the handling property is also good. Further, the front Pd alloy film 5 is formed by electroplating from the surface 2a side of the porous support 2 after the metal plate 10 is removed by selective etching, and the front Pd alloy film 5 and the back Pd alloy film 7c in the hole 3 are formed. Since the hydrogen permeable film 4 is formed by two times of electroplating, a thin hydrogen permeable film can be formed without defects such as pinholes.
In addition, the above-mentioned embodiment is an illustration and the manufacturing method of the hydrogen purification filter of this invention is not limited to these.

Next, the present invention will be described in more detail by showing more specific examples.
[Example]
(Etching process)
A SUS304 material having a thickness of 40 μm was prepared as a metal support. Next, a photosensitive resist material (OFPR manufactured by Tokyo Ohka Kogyo Co., Ltd.) was applied to both surfaces of this SUS304 material by a dipping method (application amount: 7 μm (when dry)). Next, the resist coating films on both sides were exposed through a predetermined photomask and developed using an aqueous sodium hydrogen carbonate solution. Thus, a resist pattern having a plurality of circular openings with a diameter of 80 μm at a pitch of 110 μm was formed on both surfaces of the SUS304 material. The circular openings on the front and back sides face each other with the SUS304 material interposed therebetween.

Next, using the resist pattern as a mask, the SUS304 material was etched by spraying from both sides under the following conditions.
(Etching conditions)
・ Temperature: 50 ℃
・ Ferric chloride concentration: 45 Baume ・ Pressure: 0.30 MPa
After the above etching treatment was completed, the resist pattern was removed using sodium hydroxide and washed with water. As a result, a plurality of holes were formed to form a porous support. These holes had a circular cross section with an opening diameter of 90 μm on the surface of the SUS304 material and an opening diameter of 85 μm at the center in the depth direction.

(Diffusion prevention layer forming process)
A photosensitive resist material (OFPR manufactured by Tokyo Ohka Kogyo Co., Ltd.) was applied to both surfaces of the porous support prepared as described above by a dipping method (application amount: 7 μm (when dried)). Next, one surface of the porous support was shielded with a mask to expose the resist coating film, and developed using an aqueous sodium hydrogen carbonate solution. Thus, a resist pattern was formed so that only one surface of the porous support was exposed.
Next, using the resist pattern as a mask, a thin film (thickness 1 μm) of titanium nitride (TiN) is formed by ion plating on the surface where the porous support is exposed, and then the resist pattern is formed using sodium hydroxide. Removed and washed with water. This formed the diffusion prevention layer on one surface of the porous support.

(First electroplating process)
A copper plate (thickness: 200 μm) was adhered and fixed to the surface of the porous support on which the diffusion prevention layer was formed using a clip.
Next, electroplating was performed on the surface of the porous support not provided with the copper plate under the following conditions. As a result, a back Pd alloy film (alloy of Pd and Ag, thickness 0.5 μm, Pd content 80%) was formed on the porous support surface including the inside of the pores.
(Electroplating (formation of back Pd alloy film) conditions)
-Bath used: Pd chloride plating bath (Pd concentration: 12 g / L)
・ PH: 7-8
・ Current density: 1 A / dm ²
・ Liquid temperature: 40 ℃

(Second electroplating process)
Next, the copper plate is removed by selective etching using an ammonia copper complex salt, and a front Pd alloy film (Pd and Ag alloy, thickness 5 μm, Pd content 80%) is formed on the exposed surface by electroplating under the following conditions. Formed. Of the front Pd alloy film formed in this way, the layered portion with the back Pd alloy film already formed in the hole was used as the hydrogen permeable film. Thereby, the hydrogen purification filter of the present invention was produced.
(Electroplating (formation of front Pd alloy film))
-Bath used: Pd chloride plating bath (Pd concentration: 12 g / L)
・ PH: 7-8
・ Current density: 1 A / dm ²
・ Liquid temperature: 40 ℃

The hydrogen purification filter is cut to a size of 3 cm × 3 cm and attached to a reformer, and a mixture of methanol and steam is continuously supplied for 100 hours under high temperature and high pressure conditions (500 ° C., 0.50 MPa). The CO concentration of the hydrogen rich gas permeating to the porous support side and the flow rate of the hydrogen rich gas were measured. As a result, the CO concentration from immediately after the start of reforming until 300 hours elapses is as extremely low as 5 to 10 ppm, and the flow rate of the hydrogen-rich gas is 1.5 L / min, and the hydrogen purification filter of the present invention is excellent. It was confirmed to have durability and hydrogen permeation efficiency.
Further, no warpage was observed during the production process and in the produced hydrogen purification filter.

[Comparative Example 1]
A SUS304 material having a thickness of 40 μm was prepared as a first support. Next, a Pd alloy film (thickness 5 μm) was formed on one surface of this SUS304 material by electrolytic plating under the following conditions to obtain a hydrogen permeable membrane.
(Pd alloy film deposition conditions)
-Bath used: Pd chloride plating bath (Pd concentration: 12 g / L)
・ PH: 7-8
・ Current density: 1 A / dm ²
・ Liquid temperature: 40 ℃
Next, a photosensitive resist material (OFPR manufactured by Tokyo Ohka Kogyo Co., Ltd.) was applied to both surfaces of this SUS304 material by a dipping method (application amount: 7 μm (when dried)). Next, the resist coating films on both sides were exposed through a predetermined photomask and developed using an aqueous sodium hydrogen carbonate solution. As a result, a resist pattern having a plurality of circular openings with a diameter of 80 μm at a pitch of 110 μm was formed on the surface of the SUS304 material where the hydrogen permeable film was not formed.

Next, using the resist pattern as a mask, SUS304 material was etched by spraying from one side under the following conditions.
(Etching conditions)
・ Temperature: 50 ℃
・ Ferric chloride concentration: 45 Baume ・ Pressure: 0.30 MPa
After the above etching treatment was completed, the resist pattern was removed using sodium hydroxide and washed with water. As a result, a plurality of holes were formed in the first support. These holes have a tapered shape with an opening diameter of 85 μm on the surface side of the SUS304 material, and an opening diameter of 45 μm at the innermost part in the depth direction (part where the hydrogen permeable membrane is exposed). .

Moreover, SUS304 material with a thickness of 40 μm was prepared as the second support. Next, a photosensitive resist material (OFPR manufactured by Tokyo Ohka Kogyo Co., Ltd.) was applied to both surfaces of this SUS304 material by a dipping method (application amount: 7 μm (when dry)). Next, the resist coating films on both sides were exposed through a predetermined photomask and developed using an aqueous sodium hydrogen carbonate solution. Thus, a resist pattern having a plurality of circular openings with a diameter of 80 μm at a pitch of 110 μm was formed on both surfaces of the SUS304 material. The circular openings on the front and back sides face each other with the SUS304 material interposed therebetween.
Next, using the resist pattern as a mask, the SUS304 material was etched by spraying from both sides under the following conditions.
(Etching conditions)
・ Temperature: 50 ℃
・ Ferric chloride concentration: 45 Baume ・ Pressure: 0.30 MPa

After the above etching treatment was completed, the resist pattern was removed using sodium hydroxide and washed with water. In this way, a plurality of holes were drilled to form a second support. These holes had a circular cross section with an opening diameter of 85 μm on the surface of the SUS304 material and an opening diameter of 80 μm at the center in the depth direction.
Next, the second support was joined to the hydrogen permeable membrane supported by the first support by laser welding, and then cut to a size of 3 cm × 3 cm to obtain a hydrogen purification filter. In this joining, alignment was performed so that the hole of the first support and the hole of the second support face each other with the hydrogen permeable membrane interposed therebetween.
The hydrogen purification gas produced in this way is attached to the reformer, and a mixture of methanol and water vapor is supplied to the Pd alloy membrane of the filter under the same high-temperature and high-pressure conditions as in the examples, and the hydrogen-rich gas that permeates to the porous support side of the filter The CO concentration and the flow rate of the hydrogen rich gas were measured. As a result, the CO concentration from the start of reforming to the elapse of 300 hours was as extremely low as 5 to 10 ppm, but the flow rate of the hydrogen-rich gas was as low as 0.6 L / min.

[Comparative Example 2]
The diameter of the circular opening of the resist pattern formed on the SUS304 material is 95 μm, the opening diameter on the surface side of the SUS304 material of the hole formed in the first support by etching is 100 μm, and the deepest part in the depth direction (hydrogen permeation) A hydrogen purification filter was produced in the same manner as in Comparative Example 1 except that the opening diameter at the part where the membrane was exposed was 60 μm.
This hydrogen purification filter is attached to a reformer, and a mixture of methanol and water vapor is continuously supplied for 100 hours under high-temperature and high-pressure conditions (300 ° C., 0.50 MPa), and CO of hydrogen-rich gas that permeates to the porous support side of the hydrogen purification filter. The concentration and the flow rate of the hydrogen rich gas were measured. As a result, the CO concentration from the start of reforming to the elapse of 300 hours was as extremely low as 5 to 10 ppm, and the flow rate of the hydrogen rich gas was 1.1 L / min. However, in the process for producing the hydrogen purification filter, warpage occurred at the stage where the hole was formed in the first support, and the workability in the subsequent process was extremely poor.

  It can be used in various fields that require high-purity hydrogen-rich gas.

It is a fragmentary sectional view showing one embodiment of the hydrogen purification filter of the present invention. It is process drawing which shows one Embodiment of the manufacturing method of the hydrogen purification filter of this invention. It is process drawing which shows one Embodiment of the manufacturing method of the hydrogen purification filter of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Hydrogen purification filter 2 ... Porous support 3 ... Hole part 4 ... Hydrogen permeable film 5 ... Front surface Pd alloy film 6 ... Diffusion prevention layer 7, 7a, 7b, 7c ... Back surface Pd alloy film 8 ... Metal support 9 ... Resist Pattern 10 ... Metal plate

Claims (11)

  A porous support having a plurality of holes, a front Pd alloy film disposed on one surface of the porous support so as to cover the holes, and between the front Pd alloy film and the porous support An interstitial diffusion prevention layer, the other surface of the porous support including the inner wall surface of the hole, and a back surface Pd alloy film disposed on the front surface Pd alloy film located in the hole, A hydrogen purification filter, wherein a laminated portion of the front Pd alloy film and the back Pd alloy film located in the hole is a hydrogen permeable film.   2. The hydrogen purification filter according to claim 1, wherein the total opening area of the pores occupies 20 to 90% of the area of the porous support.   The hydrogen purification filter according to claim 1 or 2, wherein the porous support is stainless steel.   The thickness of the said porous support body is in the range of 10-100 micrometers, The thickness of the said hydrogen permeable film is in the range of 1-13 micrometers, The hydrogen in any one of Claim 1 thru | or 3 characterized by the above-mentioned. Purification filter.   5. The diffusion preventing layer is a conductive thin film made of at least one of titanium nitride, titanium carbide, tantalum nitride, tantalum carbide, and chromium nitride. Hydrogen purification filter. A porous support having a plurality of holes is formed by forming a resist pattern having a plurality of openings on both surfaces of a metal support and etching the metal support from the front and back using the resist pattern as a mask to form holes. An etching process for producing a body;
A diffusion prevention layer forming step of forming a conductive diffusion prevention layer on one surface of the porous support;
A metal plate that can be selectively etched with respect to the porous support is fixed to the surface of the porous support with the diffusion prevention layer, and the inner surface of the hole is formed by electroplating from the other surface side of the porous support. A first electroplating step of forming a back Pd alloy film on a porous support including a wall surface and on the metal plate located in the hole;
A front Pd alloy film is formed by electroplating on the exposed surface of the metal plate removed by selective etching, and a second electric region is formed by using a laminated portion of the front Pd alloy film and the back Pd alloy film as a hydrogen permeable film. A method for producing a hydrogen purification filter, comprising: a plating step.   The method for producing a hydrogen purification filter according to claim 6, wherein the metal support is stainless steel, and the metal plate is copper or nickel.   The said etching process WHEREIN: A some hole is drilled so that the sum total of the opening area of the said hole may occupy 20 to 90% of the area of the said porous support body, The Claim 6 or Claim 7 characterized by the above-mentioned. The manufacturing method of the hydrogen purification filter of description.   The diffusion prevention layer forming step includes forming a diffusion prevention layer made of at least one of titanium nitride, titanium carbide, tantalum nitride, tantalum carbide, and chromium nitride by a vacuum film formation method. 9. A method for producing a hydrogen purification filter according to any one of 8 above.   The hydrogen purification according to any one of claims 6 to 9, wherein, in the first electroplating step, the back surface Pd alloy film is formed to have a thickness in a range of 0.1 to 3 µm. A method for manufacturing a filter.   11. The hydrogen purification filter according to claim 6, wherein, in the second electroplating step, the front Pd alloy film is formed to have a thickness in a range of 1 to 10 μm. Production method.

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