JP4274678B2 - Gas separation unit and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gas separation unit for separating a specific gas in a mixed gas and a method for producing the same.
[0002]
[Prior art]
Conventionally, as a method for separating a specific gas in a mixed gas, a method using an adsorbent, a method using a separation membrane, and the like are known. As a method using a separation membrane, for example, there is a method of separating a gas with an organic or inorganic separation membrane. A method using a separation membrane has attracted attention in terms of energy saving, separation efficiency, simplicity of apparatus configuration, ease of operation, and the like.
[0003]
The thinner the separation membrane used for membrane separation, the better the permeation characteristics. On the other hand, the probability of pinholes occurring in the separation membrane increases. If pinholes are present, selective separation of high purity gas becomes difficult and does not serve as a separation membrane. Therefore, conventionally, a material having a thickness of about 20 to 50 μm, which has a low probability of pinholes, has been used. At this thickness, the permeation characteristics were inferior, and sufficient characteristics as a separation membrane could not be exhibited.
[0004]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION An object of the present invention is to provide a gas separation unit having no pinhole and excellent gas selective permeation characteristics and a method for producing the same when producing a selective separation apparatus for mixed gas.
[0005]
[Means for Solving the Problems]
(1) The manufacturing method of the gas separation unit of the present invention includes:
A step of activating the one side of the metal plate for the extension frame by sputter etching;
A step of activating the one side of the metal plate having gas separation by sputter etching;
A step of producing a clad plate by cold-welding each of the activated surfaces together;
Rolling the clad plate to form a thin film;
Etching the thinned metal plate for the extending frame,
The unetched part is used as an extension frame,
Forming an opening that exposes the surface of the metal plate having gas separation properties in the etched portion;
And laminating a metal support having a large number of holes formed on the other surface of the metal plate having gas separation property.
(2) Moreover, the manufacturing method of the gas separation unit of this invention WHEREIN: In above-mentioned (1),
The metal plate having gas separation property is a palladium plate or a palladium alloy plate, and the metal plate for a frame is a stainless steel plate.
(3) Furthermore, the manufacturing method of the gas separation unit of the present invention is as described in (1) or (2) above.
A reduction ratio of rolling the clad plate to form a thin film is 20 to 70%.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the gas separation unit of the present invention will be described with reference to the drawings by taking a separation unit for separating hydrogen gas as an example.
FIG. 1 is a perspective view showing the structure of the hydrogen gas separation unit A. FIG. In FIG. 1, a hydrogen gas separation unit A has a stretchable frame 10 laminated on one side of a material 13 having a hydrogen gas separation property (for example, a palladium alloy foil. Hereinafter, a palladium alloy foil will be described as an example). On the other surface, a metal support 11 having a large number of holes is laminated.
[0007]
As shown in FIG. 1, the extension frame 10 laminated on the upper surface of the hydrogen gas separation unit A is a frame body in which two openings 105 are formed in the center by an etching method or the like. Various shapes such as a quadrangle, a hexagon, a circle, and an ellipse can be applied to the opening 105. The arrangement is not particularly limited. It is preferable that the extension frame 10 is opened as large as possible in order to increase the gas distribution area. For example, it is also preferable to use a framework having only the peripheral portion 101.
In consideration of the tearing of the palladium alloy foil 13 during handling, it is also preferable to provide a central portion 102 as shown in FIG. The material of the extension frame 10 is preferably stainless steel, nickel or nickel-base alloy, copper or copper alloy, iron alloy, or the like. The thickness of the extension frame 10 is preferably 10 to 500 μm, and more preferably about 50 to 200 μm. If the thickness is less than 10 μm, the mechanical strength as a frame is lacking. On the other hand, if it exceeds 500 μm, it takes a long time to form by, for example, an etching method.
[0008]
Next, the metal support 11 laminated on the other surface of the palladium alloy foil 13 will be described. The metal support 11 is formed with circular or elliptical pores b having a diameter of 10 to 500 μm, preferably 50 to 200 μm. If the diameter is less than 10 μm, the gas flow resistance is large. On the other hand, if it exceeds 500 μm, the palladium alloy foil 12 bites into the pores b, and the palladium alloy foil 13 tends to crack. The formation density of the pores b is preferably about 150 to 3000 / cm ² .
[0009]
Further, as shown in FIG. 1, the shape of the pore b may be a long hole shape with one extremely large diameter. The arrangement state of the pores b may be any arrangement, but it is preferable to arrange them in a staggered manner because the hole formation density can be increased.
[0010]
The metal support 11 is preferably a metal plate such as a stainless steel plate, nickel or nickel base alloy plate, copper or copper alloy plate, or iron alloy plate. The metal support 11 can also be made of a porous inorganic material such as ceramics.
[0011]
The thickness of the metal support 11 is preferably 10 to 500 μm, and more preferably about 30 to 200 μm. If the thickness is less than 10 μm, the mechanical strength as a support is lacking. On the other hand, if it exceeds 500 μm, it takes a long time to form pores by, for example, an etching method.
[0012]
Next, the palladium alloy foil 13 will be described. The palladium alloy foil 13 is a thin foil made of an alloy mainly composed of palladium. The palladium alloy foil 13 includes a group VIII element (for example, cobalt, nickel), a group IB (for example, copper, silver, gold), a group IIIB of the periodic table. A material obtained by alloying at least one other metal selected from the group of (for example, yttrium) is preferably used. Among these, an alloy foil of palladium and silver (for example, containing 23% silver) and an alloy foil of palladium and holmium (for example, containing 8% holmium) are more preferable.
The content of the element alloyed with palladium is preferably 1 to 50% by weight, more preferably 10 to 30% by weight. The reason why the palladium alloy is used is that hydrogen embrittlement occurs in the simple substance of palladium, and hydrogen embrittlement can be prevented when the content of the alloy element is 1% by weight or more.
In addition, if the content of the alloy element exceeds 50% by weight, the hydrogen permeation rate becomes slow, which is not preferable.
[0013]
The thickness of the palladium alloy foil 13 is preferably 2 to 20 μm from the viewpoint of gas permeability and the like. More preferably, it is 5-10 micrometers. If the thickness of the palladium alloy foil 13 is less than 2 μm, pinholes are likely to be present in the palladium alloy foil 13 and the purity of the separated hydrogen is also lowered. On the other hand, when the thickness exceeds 20 μm, the permeation rate of hydrogen becomes slow.
In addition, although palladium alloy foil was demonstrated as an example as a material which has hydrogen gas-separation property, in the case of isolate | separating other gas, what has the separation characteristic of the gas is selected suitably, and is used. Various shapes such as a plate shape and a foil shape can be used. Here, “having gas separation property” means having a function of selectively separating a specific gas from a mixed gas containing the specific gas.
[0014]
Next, the manufacturing method of the gas separation unit of this invention is demonstrated.
FIG. 2 is a schematic view of a clad plate processing apparatus showing an example of a gas separation unit manufacturing process. First, a palladium alloy foil 23 is clad and laminated on one side of a metal plate 21 that serves as a stretch frame. In the clad processing, the metal plate 21 whose surface has been cleaned in advance is wound around the rewind reel 22 of the clad plate processing apparatus shown in FIG.
The thickness of the metal plate 21 is preferably 20 to 1000 μm in anticipation of the thickness reduction in the next reroll.
Similarly, the palladium alloy foil 23 whose surface has been cleaned in advance is wound around the rewind reel 24.
As the palladium alloy foil, one having a thickness of 6 to 100 μm, which is thicker than the finished thickness, can be used. Since a thicker one can be used, handling during clad can be performed easily.
The metal plate 21 and the palladium alloy foil 23 are simultaneously rewound from the rewinding reels 22 and 24, wound around the electrode rolls 26 and 26 protruding into the etching chamber 25, and the respective mating surfaces are sputter etched in the etching chamber 25. Process to activate.
[0015]
The method of performing the activation process by the sputter etching process is as follows. (1) Extremely low pressure of 1 × 10 ⁻¹ to 1 × 10 ⁻⁴ Torr as disclosed in Japanese Patent Application Laid-Open No. 1-2224184 by the present applicant. In an inert gas atmosphere, (2) the metal plate 21 and the palladium alloy foil 23 are each grounded as one electrode, and an alternating current of 1 to 50 MHz is applied between the other insulated and supported electrodes. Glow discharge is performed, and (3) and the area of the electrode exposed in the plasma generated by the glow discharge is 1/3 or less of the area of the electrode, and (4) sputter etching is performed. preferable.
Thereafter, clad processing (cold pressure welding) is performed by a rolling unit 27 provided in the vacuum chamber 20, and a clad plate 29 having a two-layer structure is wound around a take-up roll 28 and a clad plate 29 having a two-layer laminated structure is taken up. To manufacture.
[0016]
Rolling process (reroll)
The clad plate 29 is again passed through a roll, and the thickness of both the metal plate 21 and the palladium alloy foil 23 is reduced to form a thin film. The rolling reduction is preferably 20 to 70%. If it is less than 20%, the palladium alloy foil 23 is not thinned in the rolling process. If it exceeds 70%, the joining interface of the clad plate is wavy in rolling, the thickness of the foil becomes uneven, and the film as a whole is not formed. Strength decreases. For example, a silver / palladium alloy foil with an initial thickness of 20 μm and a stainless steel plate with an initial thickness of 200 μm laminated by a clad process were rolled at a reduction ratio of 50%. As a result, each thickness decreased by 50%. Things were obtained.
The rolling may be performed in a vacuum, but since it has already been bonded, the bonding strength does not deteriorate even if it is performed in the atmosphere.
[0017]
Next, the clad plate 29 produced in this way is cut into an appropriate vertical and horizontal size to form a clad cut plate K (see FIG. 3A), which is used as the original plate of the hydrogen gas separation unit.
Next, an opening 105 is formed by etching on one side of the clad cut plate K obtained in the previous step. As an etching method, first, a negative resist 31 was applied to one side (metal plate 21) of the clad cut plate K (see FIG. 3B), and after baking, a pattern corresponding to the opening 105 was formed. Exposure is performed by irradiating light such as ultraviolet rays through a mask. After the exposure, development is performed (see FIG. 3C), post baking is performed, etching is performed, and the remaining resist is removed, thereby completing the stretch frame 10.
[0018]
In addition, in order to improve the resist adhesion on the metal plate 21, as a pretreatment, the clad cut plate K is washed with an aqueous solution of sodium hydroxide in advance, washed with water, neutralized, dried, etc. to clean the resist coating surface. It is desirable to do. Examples of the resist type include water-soluble types such as casein type and PVA type, and acrylic polymer solvent-soluble types. As the resist coating conditions, for example, the following are preferable.
Resist type: PVA-dichromic acid water-soluble type (Fuji Pharmaceutical Co., Ltd., FR-14)
Application thickness: 7μm
As a method of applying the resist to the cleaned metal plate 21, a roll coating method, a spin coating method, a dip pulling coating method, or the like is used.
[0019]
The coating thickness varies depending on the resist viscosity, the pulling speed, and the like, but is preferably 3 to 15 μm from the viewpoint of resolution. Next, a film mask on which a pattern image is formed in advance is brought into close contact with the film of the resist 31, and ultraviolet rays are irradiated for about 60 to 70 seconds.
[0020]
In the next development step, the unexposed resist is dissolved and removed, the surface of the metal plate 21 is exposed, and the portion to be etched in the subsequent step (see FIG. 3C). The development was performed by spraying water. Prior to the etching process, the resist 31 film in which the pattern to be the opening 105 is formed is preferably post-baked using hot air, deep ultraviolet radiation, or the like in order to improve the adhesion of the coating film. Usually, it is carried out at 100 to 120 ° C. for 15 to 30 minutes.
[0021]
The etching of the metal plate 21 is preferably performed in two stages.
First, it is preferable to spray a ferric chloride aqueous solution of 45 to 49 ° Be (Baume) on the object surface as the first stage etching. The liquid temperature of the ferric chloride aqueous solution is preferably 45 to 65 ° C. The first stage etching is performed for 80 to 90% of the total etching amount. Next, the second stage etching is performed. In the second stage etching, electrolytic etching is performed to completely remove the remaining metal plate 21. As the electrolytic etching solution, it is desirable to use a phosphoric acid solution, but the type is not particularly limited as long as it can etch a metal plate. The etched metal plate 21 is washed with water, removed from the resist, and a framed palladium alloy foil p, which is a part of the hydrogen gas separation unit A and in which the extension frame 10 and the palladium alloy foil 13 are integrated, is obtained. .
In the etching treatment of this example, the etching solution was sprayed from one side so that the area of the opening 105 of the metal plate was 70 mm × 140 mm. The resist was removed by immersing a 5 to 10% by weight sodium hydroxide aqueous solution in a solution heated to 50 to 70 ° C. In the present embodiment, the manufacturing method of the laminated body in which the metal plate 21 and the palladium alloy foil 23 are integrated has been described using the clad method, but the both can be laminated by other methods. For example, the laminated body which integrated the metal plate 21 and the palladium alloy foil 23 using an adhesive agent can also be manufactured.
Alternatively, the central portion of the metal plate can be punched out in advance by a press method or the like to create a frame, and the frame can be integrated with the palladium alloy foil using a welding method.
[0022]
Next, the metal support plate 11 as shown in FIG. 1 is applied to the lower side of the frame-equipped palladium alloy foil p created in the above-described process, thereby completing the hydrogen gas separation unit A of the present invention. The hydrogen gas separation unit A completed as described above is fixed to the case 34 by laser welding or the like so that the surface of the metal support plate 11 is on the inside to form a hydrogen gas separator Y (FIG. 5). reference).
[0023]
Next, an example of a method for separating hydrogen using the hydrogen gas separation unit A of the present invention will be described with reference to FIG. As shown in FIG. 4, the hydrogen gas separator X is provided with a hydrogen gas separator X incorporating the hydrogen gas separation unit A of the present invention.
[0024]
When the source gas Gg is introduced from the source gas introduction pipe 42 at the upper part of the hydrogen gas separator X, the hydrogen gas in the source gas Gg permeates the palladium alloy foil 13 of the hydrogen gas separation unit 105 and passes through the permeate gas Gt. Is taken out from the lower separated gas discharge pipe 41. On the other hand, the non-permeating gas Gn is discharged from the upper part 43 of the hydrogen gas separator X to the outside of the system.
[0025]
【The invention's effect】
In the hydrogen gas separation unit of the present invention, the exposed area of the hydrogen gas separation material (palladium alloy foil) is large, and the palladium alloy foil is in a state of being stretched by the stretch frame, so that the palladium alloy foil is not destroyed. A hydrogen gas separation unit can be manufactured.
Moreover, since the metal support plate is applied to the lower side of the palladium alloy foil, the palladium alloy foil is not broken by the pressure of the source gas.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view for explaining the structure of a hydrogen gas separation unit.
FIG. 2 is a schematic view of a clad plate processing apparatus showing a part of a manufacturing process of a hydrogen gas separation unit.
FIG. 3 is an explanatory view of etching a clad cut plate K. FIG.
FIG. 4 is an explanatory diagram showing an example of a method for separating hydrogen using a hydrogen gas separation unit.
5 is a schematic perspective view of a hydrogen gas separator Y. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Extension frame 11 ... Metal support 13 ... Material which has hydrogen gas-separability (palladium alloy foil)
20 ... Vacuum chamber 21 ... Metal plate 22 ... Rewinding reel 23 ... Material with hydrogen gas separation (palladium alloy foil)
24 ... Rewinding reel 25 ... Etching chamber 26 ... Electrode roll 28 ... Take-up reel 29 ... Cladding plate 31 ... Resist 41 ... Separation gas discharge pipe 42 ... Raw material Gas introduction pipe A ... Hydrogen gas separation unit K ... Cladding plate X ... Hydrogen gas separator Y ... Hydrogen gas separator Gg ... Raw gas Gt ... Permeated gas Gn ... Non-permeating gas

Claims (3)

A step of activating the one side of the metal plate for the extension frame by sputter etching;
A step of activating the one side of the metal plate having gas separation by sputter etching;
A step of producing a clad plate by cold-welding each of the activated surfaces together;
Rolling the clad plate to form a thin film;
Etching the thinned metal plate for the extending frame,
The unetched part is used as an extension frame,
Forming an opening that exposes the surface of the metal plate having gas separation properties in the etched portion;
Laminating a metal support having a large number of holes formed on the other surface of the metal plate having gas separation properties;
A method for producing a gas separation unit comprising : The method for producing a gas separation unit according to claim 1 , wherein the metal plate having gas separation property is a palladium plate or a palladium alloy plate, and the metal plate for the frame is a stainless steel plate . The method for producing a gas separation unit according to claim 1 or 2, wherein a rolling reduction ratio of rolling the clad plate to form a thin film is 20 to 70% .

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