JP2004331434A - Microreacter for hydrogen production and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small microreactor which shows a high efficiency and realizes a reformer for hydrogen production which is excellent in mechanical stability, and a manufacturing method which enables easy manufacturing of the microreactor. <P>SOLUTION: The microreactor has a structure comprising a metal substrate which is made of aluminum or an aluminum alloy and has a fine groove part on one side, a catalyst supported inside the fine groove part and a cover member which has a raw material inlet and a gas outlet and is bonded to the metal substrate to cover the fine groove part. The cover member is made of aluminum or an aluminum alloy and has a surface-treated layer on at least the surface bonded to the metal substrate. The microreactor shows a high efficiency of heat transfer from a heating unit to the supported catalyst, has a high mechanical strength, enables easy processing of the metal substrate and therefore can be easily manufactured. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a microreactor used in a reformer for hydrogen production, particularly to a microreactor for reforming a raw material such as methanol to obtain hydrogen gas, and a method for producing the microreactor.
[0002]
[Prior art]
[Patent Document 1] Japanese Patent Application Laid-Open No. 2002-252014 In recent years, attention has been paid to using hydrogen as a fuel because there is no generation of global warming gas such as carbon dioxide from the viewpoint of protection of the global environment and energy efficiency is high. Have been. In particular, fuel cells have attracted attention because they can directly convert hydrogen into electric power and can achieve high energy conversion efficiency in cogeneration systems that use generated heat. Until now, fuel cells have been adopted under special conditions such as space development and marine development.Recently, fuel cells for automobiles and homes have been developed, and fuel cells for portable devices have also been developed. ing.
[0003]
In a fuel cell, hydrogen gas obtained by reforming a hydrocarbon-based fuel such as natural gas, gasoline, butane gas, or methanol, and oxygen in the air are electrochemically reacted with each other to extract electricity. The fuel cell system generally includes a reformer that generates hydrogen gas by steam reforming a hydrocarbon-based fuel, and a fuel cell body that generates electricity.
In a reformer for obtaining hydrogen gas by steam reforming using methanol or the like as a raw material, steam reforming of the raw material is performed by an endothermic reaction mainly using a Cu—Zn-based catalyst. In an industrial fuel cell, starting and stopping are not performed frequently, so that the temperature of the reformer hardly fluctuates. However, in the case of fuel cells for automobiles and portable devices, since the starting and stopping are performed frequently, the reformer rises quickly when started from the stopped state (the time required to reach the steam reforming temperature of the raw material is short). Short) is required.
On the other hand, especially for portable equipment, miniaturization of the fuel cell is essential, and various miniaturizations of the reformer are being studied. For example, a microreactor in which a microchannel is formed on a silicon substrate or a ceramic substrate and a catalyst is supported in the microchannel has been developed (Patent Document 1).
[0004]
[Problems to be solved by the invention]
However, the conventional microreactor has a problem in that the heat utilization efficiency is poor, and the reformer has a low rise speed when started from a stopped state. In addition, there is a problem that processing by a micro machine or the like is required, and the manufacturing cost is high.
The present invention has been made in view of the above-described circumstances, is a small and highly efficient, and a microreactor that enables a hydrogen production reformer with excellent mechanical stability, and a microreactor. It is an object of the present invention to provide a manufacturing method that can be easily manufactured.
[0005]
[Means for Solving the Problems]
In order to achieve such an object, the present invention provides a microreactor for reforming a raw material to obtain hydrogen gas, comprising a metal substrate made of aluminum or an aluminum alloy having a fine groove on one surface; A catalyst supported in the fine groove portion, comprising a cover member joined to the metal substrate to cover the fine groove portion and having a material inlet and a gas outlet, wherein the cover member is made of any of aluminum and an aluminum alloy And a structure having a surface treatment layer on at least the bonding surface with the metal substrate.
[0006]
As another aspect of the present invention, the surface treatment layer of the cover member is configured to contain at least one of zinc, tin, gold, and copper.
As another aspect of the present invention, the metal substrate is provided with a heating element via an insulating film on a surface opposite to the fine groove portion forming surface, and the insulating film is formed by anodizing the metal substrate. The structure was such that the metal oxide film was formed.
As another aspect of the present invention, the configuration is such that the metal oxide film is also formed in the fine groove.
As another aspect of the present invention, a configuration is provided in which a heating element protection layer is provided so as to expose the electrodes of the heating element and cover the heating element.
[0007]
Further, the present invention provides a method of manufacturing a microreactor for reforming a raw material to obtain hydrogen gas, wherein a groove forming step of forming a fine groove on one surface of a metal substrate made of aluminum or an aluminum alloy; A catalyst supporting step of supporting a catalyst in the groove portion, and a surface treatment of forming a surface treatment layer on at least a surface of the cover member made of aluminum or aluminum alloy having a material inlet and a gas outlet formed thereon, the surface being joined to the metal substrate. And a joining step of diffusing and joining the cover member to the metal substrate so as to cover the fine groove.
[0008]
In another aspect of the present invention, the surface treatment step is a step of forming a thin film containing at least one of zinc, tin, gold and copper.
As another aspect of the present invention, the surface treatment step is configured to be a double zincate treatment.
As another aspect of the present invention, between the groove forming step and the catalyst supporting step, an insulating film forming step of providing an insulating film on at least the metal substrate surface on which the fine groove is not formed; And a heating element providing step of providing a heating element thereon.
In another aspect of the present invention, the insulating film forming step is a step of forming a metal oxide film by anodizing the metal substrate.
[0009]
In the present invention as described above, the heat conductivity of the metal substrate made of aluminum or an aluminum alloy is high and the heat capacity is small, so that heat is transferred from the heating element to the supported catalyst with high efficiency. The surface treatment layer interposed between them functions to improve the adhesion between them.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Microreactor FIG. 1 is a perspective view showing one embodiment of the microreactor of the present invention, and FIG. 2 is an enlarged vertical sectional view taken along line II-II of the microreactor shown in FIG. 1 and 2, a microreactor 1 of the present invention includes a metal substrate 2 made of aluminum or an aluminum alloy, a fine groove 3 formed on one surface 2 a of the metal substrate 2, the inside of the fine groove 3, An insulating film 4 made of a metal oxide film formed on both surfaces 2a and 2b and a side surface 2c of the metal substrate 2; a heating element 5 provided on the surface 2b of the metal substrate 2 via the insulating film 4; And a cover member 8 joined to the metal substrate 2 so as to cover the fine groove 3. Electrodes 6 and 6 are formed on the heating element 5, and a heating element protection layer 7 having electrode openings 7 a and 7 a so that the electrodes 6 and 6 are exposed is provided so as to cover the heating element 5. I have. The cover member 8 is made of aluminum or an aluminum alloy, has a raw material inlet 8a and a gas outlet 8b, and has a surface treatment layer 9 on both surfaces. The cover member 8 is joined to the metal substrate 2 via the surface treatment layer 9, and the insulating film 4 does not exist on the joint surface between the two.
[0011]
FIG. 3 is a perspective view showing the micro-reactor 1 shown in FIG. As shown in FIG. 3, the fine groove portion 3 is formed so as to leave the comb-shaped ribs 2A and 2B, and has a shape continuous from the end 3a to the end 3b. By positioning the material inlet 8a of the cover member 8 at the end 3a and the gas outlet 8b at the end 3b, a continuous flow path is formed from the material inlet 8a to the gas outlet 8b. .
The metal substrate 2 constituting the microreactor 1 of the present invention is made of aluminum or an aluminum alloy as described above. As the aluminum alloy, JIS1000, 2000, 3000, 5000, 6000, and 7000 series materials and the like can be used. Such a metal substrate 2 can form a metal oxide film (insulating film 4) by anodic oxidation, and is preferably used in view of workability, characteristics such as heat capacity and thermal conductivity, and unit price. The thickness of the metal substrate 2 can be appropriately set in consideration of the size of the microreactor 1, the heat capacity of the metal material to be used, characteristics such as thermal conductivity, the size of the fine groove 3 to be formed, and the like. , 50 to 2000 μm.
[0012]
In forming such a metal oxide film (insulating film 4) on the metal substrate 2 by anodic oxidation, the metal substrate 2 is connected to the anode of the external electrode, immersed in an anodic oxidation solution, opposed to the cathode, and energized. It can be done by doing. The thickness of the metal oxide film (insulating film 4) can be set, for example, in a range of about 5 to 150 μm.
The fine groove 3 formed in the metal substrate 2 is not limited to the shape as shown in FIG. 3, but the amount of the catalyst C supported in the fine groove 3 increases, and the raw material is mixed with the catalyst C. Any shape can be used so that the length of the contacting flow path becomes long. Usually, the depth of the fine groove 3 can be set in the range of about 100 to 1000 μm, the width can be set in the range of about 100 to 1000 μm, and the flow path length can be set in the range of about 30 to 300 mm.
[0013]
In the present invention, since the insulating film 4 made of a metal oxide film is also formed inside the fine groove portion 3, the carrying amount of the catalyst C is increased by the surface structure of the metal oxide film having the fine pores, and the stable catalyst is formed. Carrying becomes possible.
As the catalyst C, a known catalyst conventionally used for steam reforming can be used.
The heating element 5 constituting the microreactor 1 of the present invention is for supplying heat necessary for steam reforming of a raw material which is an endothermic reaction, and includes carbon paste, nichrome (Ni-Cr alloy), and W (tungsten). ), Mo (molybdenum) or the like. The heating element 5 has, for example, a shape in which a thin line having a width of about 10 to 200 μm is routed over the entire area of the metal substrate surface 2 b (insulating film 4) corresponding to the area where the fine groove 3 is formed. be able to.
[0014]
Electrodes 6 and 6 for energization are formed on such a heating element 5. The current-carrying electrodes 6 and 6 can be formed using a conductive material such as Au, Ag, Pd, or Pd-Ag.
The heating element protection layer 7 has electrode openings 7 a, 7 a for exposing the electrodes 6, 6, and is disposed so as to cover the heating element 5. The heating element protection layer 7 can be formed of, for example, photosensitive polyimide, varnish-like polyimide, or the like. Further, the thickness of the heating element protection layer 7 can be appropriately set in consideration of a material to be used, and can be set, for example, in a range of about 2 to 25 μm.
[0015]
The cover member 8 constituting the microreactor 1 of the present invention is made of aluminum or an aluminum alloy, and has a surface treatment layer 9 on both surfaces. As the aluminum alloy, JIS1000, 2000, 3000, 5000, 6000, and 7000 series materials and the like can be used. The surface treatment layer 9 may be a layer containing at least one of zinc, tin, gold and copper, and is particularly preferably a zinc thin film formed by zincate treatment or double zincate treatment. The thickness of the cover member 8 can be appropriately set in consideration of the material to be used and the like, and can be set, for example, in a range of about 220 to 3000 μm. The thickness of the surface treatment layer 9 is, for example, 2 to 100 μm. It can be set in the range of about. The raw material introduction port 8a and the gas discharge port 8b provided in the cover member 8 are provided so as to be located at both ends 3a and 3b of the flow path of the fine groove 3 formed in the metal substrate 2.
[0016]
FIG. 4 is a longitudinal sectional view corresponding to FIG. 2 showing another embodiment of the microreactor of the present invention. In FIG. 4, a microreactor 1 'of the present invention comprises a metal substrate 2' made of aluminum or an aluminum alloy, a fine groove 3 formed on one surface 2'a of the metal substrate 2 ', a metal substrate 2' An insulating film 4 'formed on the other surface 2'b, a heating element 5 provided on the surface 2'b of the metal substrate 2' via the insulating film 4 ', and And a cover member 8 joined to the metal substrate 2 ′ so as to cover the fine groove 3. Electrodes 6 and 6 are formed on the heating element 5, and a heating element protection layer 7 having electrode openings 7 a and 7 a so that the electrodes 6 and 6 are exposed is provided so as to cover the heating element 5. I have. The cover member 8 is made of aluminum or an aluminum alloy, has a raw material inlet 8a and a gas outlet 8b, and has a surface treatment layer 9 on both surfaces. Then, the cover member 8 is joined to the metal substrate 2 via the surface treatment layer 9.
[0017]
Such a microreactor 1 ′ is different from the above-described microreactor except that the metal member 2 ′ and the insulating layer 4 ′ are different and the metal oxide film (the insulating layer 4) is not formed in the fine groove 3. It is the same as the reactor 1, and the same components are denoted by the same reference numerals, and description thereof is omitted.
The metal substrate 2 'constituting the microreactor 1' of the present invention is made of aluminum or an aluminum alloy as described above. The thickness of the metal substrate 2 'depends on the properties of the microreactor 1', such as the size, the heat capacity of the metal used, and the thermal conductivity. The size can be appropriately set in consideration of the size of the fine groove 3 to be formed, and can be set, for example, in a range of about 50 to 2000 μm.
[0018]
'Insulating film 4 formed on the surface 2'b of' metal substrate 2, for example, be those formed by polyimide, ceramic _{(Al 2 O 3, SiO 2} ) or the like. The thickness of the insulating film 4 'can be appropriately set in consideration of the characteristics of the material to be used and the like, and can be set, for example, in a range of about 1 to 30 μm.
The microreactors 1, 1 'of the present invention as described above use metal substrates 2, 2' made of aluminum or an aluminum alloy, which have higher thermal conductivity and higher heat capacity than silicon substrates and ceramic substrates. , The heat is transferred from the heating element 5 to the supported catalyst C with high efficiency, the start-up time when starting from the stopped state is fast, and the utilization efficiency of the power input to the heating element is high, so that the reformer for hydrogen production is high. Becomes possible. In addition, the microreactors 1 and 1 'have excellent mechanical stability because the metal substrates 2 and 2' and the cover member 8 are firmly joined to each other by the surface treatment layer 9 interposed therebetween. .
[0019]
INDUSTRIAL APPLICABILITY The microreactor of the present invention can be used as any of a raw material mixing / vaporizer, a reformer, and a CO remover in a reformer for hydrogen production.
The above-described embodiment of the microreactor is an example, and the present invention is not limited thereto. For example, in the above-described embodiment, the cover member 8 includes the surface treatment layers 9 on both surfaces. However, the cover member 8 may include the surface treatment layers 9 only on the surfaces to be joined to the metal substrates 2 and 2 ′. .
[0020]
Microreactor Manufacturing Method FIGS. 5 and 6 are process diagrams for explaining one embodiment of the microreactor manufacturing method of the present invention.
5 and 6, the above-described microreactor 1 will be described as an example. In the manufacturing method of the present invention, first, in a groove forming step, a fine groove 3 is formed on one surface 2a of a metal substrate 2 made of aluminum or an aluminum alloy (FIG. 5A). The fine groove 3 is formed by forming a resist having a predetermined opening pattern on the surface 2a of the metal substrate 2 and etching the metal substrate 2 by wet etching using the resist as a mask so as to leave the comb-shaped ribs 2A and 2B. It can be formed, and processing by a micro machine can be eliminated.
[0021]
Next, in the insulating film forming step, the metal substrate 2 on which the fine groove 3 has been formed is anodized to form a metal oxide film (insulating film 4) on the entire surface including the inside of the fine groove 3 (FIG. 5B )). The formation of the metal oxide film (insulating film 4) can be performed by immersing the metal substrate 2 in an anodic oxidizing solution, facing the cathode, and supplying electricity while the metal substrate 2 is connected to the anode of the external electrode.
Next, in a heating element disposing step, a heating element 5 is provided on the metal oxide film (insulating film 4) on the surface 2b of the metal substrate 2 where the fine groove 3 is not formed. Is formed (FIG. 5C). The heating element 5 can be formed using materials such as carbon paste, nichrome (Ni-Cr alloy), W, and Mo. As a method of forming the heating element 5, a method of forming the heating element 5 by screen printing using the paste containing the above-described material, a method of forming a coating film using the paste containing the above-described material, and then patterning by etching or the like A method in which a thin film is formed using the above materials by a vacuum film forming method, and then patterned by etching or the like.
[0022]
The electrodes 6 and 6 for energization can be formed using a conductive material such as Au, Ag, Pd, or Pd-Ag. For example, the electrodes 6 and 6 are formed by screen printing using a paste containing the above conductive material. can do.
Next, a heating element protection layer 7 is formed on the heating element 5 so that the electrodes 6 and 6 are exposed (FIG. 5D). The heating element protection layer 7 can be formed using a material such as polyimide or ceramic (Al ₂ O ₃ , SiO ₂ ). For example, the electrode openings 7a, 7b are formed by screen printing using a paste containing the above material. 7a.
[0023]
Next, in the catalyst supporting step, the catalyst C is supported in the fine groove 3 (FIG. 6A). This catalyst loading can be performed by immersing the surface 2a of the metal substrate 2 on which the fine grooves 3 are formed in a desired catalyst solution. Thereafter, the metal substrate 2 is polished to expose the surface 2a of the metal substrate 2 (FIG. 6B).
On the other hand, in the surface treatment step, a surface treatment layer 9 is formed on at least the surface of the cover member 8 to be joined to the metal substrate 2 (in the illustrated example, both surfaces of the cover member 8) (FIG. 6C). The cover member 8 is made of aluminum or an aluminum alloy and has a material inlet 8a and a gas outlet 8b. As the surface treatment layer 9, a layer containing at least one of zinc, tin, gold and copper is used. Form. For example, a zinc thin film can be formed as the surface treatment layer 9 by zincate treatment or double zincate treatment. The zincate treatment and the double zincate treatment are not particularly limited, and can be performed under the conditions of conventionally known zincate treatment and double zincate treatment for aluminum. The layer containing at least one of tin, gold and copper can be formed by conventionally known displacement plating.
[0024]
Next, in the joining step, the microreactor 1 of the present invention can be obtained by joining the cover member 8 to the metal substrate surface 2a via the surface treatment layer 9 (FIG. 6D). Bonding of the cover member 8 to the metal substrate surface 2a can be performed by, for example, diffusion bonding. When diffusion bonding is used, the bonding conditions can be set at a pressure of 30 to 300 kg / cm ² and a temperature of 350 to 450 ° C.
In the joining step, the raw material inlet 8a and the gas outlet 8b provided in the cover member 8 are aligned so as to coincide with both ends of the flow path of the fine groove 3 formed in the metal substrate 2. .
[0025]
7 and 8 are process diagrams for explaining another embodiment of the microreactor manufacturing method of the present invention.
7 and 8, the above-described microreactor 1 'will be described as an example. In the manufacturing method of the present invention, first, in a groove forming step, a fine groove 3 is formed on one surface 2'a of a metal substrate 2 'made of aluminum or an aluminum alloy (FIG. 7A). The formation of the fine groove 3 can be performed in the same manner as the formation of the fine groove 3 in the metal substrate 2 described above.
Next, in an insulating film forming step, an insulating film 4 'is formed on the surface 2'b of the metal substrate 2' where the fine groove 3 is not formed (FIG. 7B). The insulating film 4 ', for example, it can be formed using polyimide, ceramic _{(Al 2 O 3, SiO 2} ) and the like. The insulating film 4 ′ is formed by, for example, forming a thin film by a printing method such as screen printing using a paste containing the above insulating material, or by a vacuum film forming method such as sputtering or vacuum evaporation using the above insulating material. It can be performed by forming and curing.
[0026]
Next, in a heating element disposing step, a heating element 5 is provided on the insulating film 4 ', and further, electrodes 6 and 6 for energization are formed (FIG. 7C). The formation of the heating element 5 and the electrodes 6 and 6 can be performed in the same manner as in the method of manufacturing the microreactor 1 described above.
Next, a heating element protection layer 7 is formed on the heating element 5 so that the electrodes 6 and 6 are exposed (FIG. 7D). The formation of the heating element protective layer 7 can be performed in the same manner as in the method of manufacturing the microreactor 1 described above.
Next, in the catalyst supporting step, the catalyst C is supported in the fine groove portion 3 (FIG. 8A). This catalyst loading can be performed by immersing the surface 2'a of the metal substrate 2 'on which the fine grooves 3 are formed in a desired catalyst solution. Thereafter, the metal substrate 2 'is polished to expose the metal substrate surface 2'a (FIG. 8B).
[0027]
On the other hand, in the surface treatment step, a surface treatment layer 9 is formed on at least the surface of the cover member 8 to be joined to the metal substrate 2 ′ (in the illustrated example, both surfaces of the cover member 8) (FIG. 8C). The surface treatment step of the cover member 8 can be performed in the same manner as in the method of manufacturing the microreactor 1 described above.
Next, in the joining step, the cover member 8 is joined to the metal substrate surface 2'a to obtain the microreactor 1 'of the present invention (FIG. 8D). The joining of the cover member 8 can be performed in the same manner as in the method of manufacturing the microreactor 1 described above.
[0028]
In such a microreactor manufacturing method of the present invention, since a metal substrate is used, it is not necessary to perform micromachine processing for forming a fine groove, and it can be easily performed by an inexpensive processing method such as etching. Reactor manufacturing costs can be reduced. In addition, since the surface treatment layer is formed on the cover member before joining with the metal substrate, both can be firmly joined.
The embodiment of the microreactor manufacturing method described above is an example, and the present invention is not limited to these embodiments.
[0029]
【Example】
Next, the present invention will be described in more detail with reference to more specific examples.
[Example]
A 1000 μm-thick aluminum substrate (250 mm × 250 mm) is prepared as a base material, and a photosensitive resist material (OFPR manufactured by Tokyo Ohka Kogyo Co., Ltd.) is applied to both surfaces of this aluminum substrate by a dipping method (film thickness 7 μm (dry)). )did. Next, a photomask having a shape in which stripe-shaped light-shielding portions having a width of 1500 μm are alternately projected from the left and right (projection length: 30 mm) at a pitch of 2000 μm on the resist coating film on the side of the aluminum substrate on which the fine grooves are to be formed, The resist coating film was exposed through this photomask and developed using a sodium hydrogen carbonate solution. Thus, on one surface of the aluminum substrate, a resist pattern is formed in which stripe-shaped openings having a width of 500 μm are arranged at a pitch of 2000 μm, and adjacent stripe-shaped openings are alternately continuous at the ends. Was done.
[0030]
Next, using the resist pattern as a mask, the aluminum substrate was etched under the following conditions. In this etching, a fine groove was formed by half-etching from one surface of the aluminum substrate, and the time required for the etching was 3 minutes.
(Etching conditions)
・ Temperature: 20 ℃
・ Etching solution (HCl) concentration: 200 g / L (200 g of 35% HCl dissolved in pure water to make 1 L)
[0031]
After the above-mentioned etching treatment was completed, the resist pattern was removed using a sodium hydroxide solution, and washed with water. As a result, stripe-shaped fine grooves having a width of 1000 μm, a depth of 650 μm, and a length of 30 mm are formed on one surface of the aluminum substrate at a pitch of 2000 μm, and are alternately continuous at the ends of adjacent fine grooves. Fine grooves (as shown in FIG. 3) (flow path length 300 mm) were formed with 8 × 5 imposition (a pitch of 25 mm in the direction of imposition and a pitch of 35 mm in the direction of imposition). (The above is the groove forming step)
[0032]
Next, the aluminum substrate was connected to the anode of the external electrode, immersed in an anodizing solution (4% oxalic acid solution) to face the cathode, and energized under the following conditions to form an aluminum oxide thin film. To form an insulating film. The thickness of the formed aluminum oxide thin film was measured by an ellipsometer and found to be about 30 μm. (The above is the insulating film forming process)
(Anodic oxidation conditions)
・ Bath temperature: 25 ℃
・ Voltage: 25V (DC)
・ Current density: 100 A / m ²
[0033]
Next, a heating element paste having the following composition was printed by screen printing on the aluminum oxide thin film of the aluminum substrate on which the fine grooves were not formed, and cured at 200 ° C. to form a heating element. The formed heating element had such a shape that a thin line having a width of 100 μm was drawn on an aluminum substrate at a line interval of 100 μm so as to cover the entire area (35 mm × 25 mm) corresponding to the area where the fine groove was formed.
(Composition of heating element paste)
Carbon powder: 20 parts by weight Fine powder silica: 25 parts by weight Xylene phenol resin: 36 parts by weight Butyl carbitol: 19 parts by weight
In addition, electrodes (0.5 mm × 0.5 mm) were formed at two predetermined positions on the heating element by screen printing using an electrode paste having the following composition.
(Composition of electrode paste)
-Silver-plated copper powder-90 parts by weight-Phenol resin-6.5 parts by weight-Butyl carbitol-3.5 parts by weight Next, the following composition was used to expose the two electrodes formed on the heating element. A heating element protection layer (thickness: 20 μm) was formed on the heating element by screen printing using the protective layer paste described above. (The above is the heating element installation process)
(Composition of paste for protective layer)
-Resin concentration ... 30 parts by weight-Silica filler ... 10 parts by weight-Lactone solvent (penta 1-4-lactone) ... 60 parts by weight
Next, the surface of the aluminum substrate on which the fine grooves were formed was immersed (10 minutes) in an aqueous catalyst solution having the following composition, and then subjected to a dry reduction treatment at 250 ° C. for 6 hours to support the catalyst in the fine grooves. (The above is the catalyst loading step)
(Composition of aqueous catalyst solution)
・ Al: 41.2% by weight
Cu: 2.6% by weight
-Zn: 2.8% by weight
[0036]
Next, the side of the aluminum substrate on which the fine grooves were formed was polished with alumina powder to expose the aluminum surface.
On the other hand, an aluminum plate (250 mm × 250 mm) having a thickness of 100 μm was prepared as a cover member, and openings were formed in this aluminum plate (a raw material inlet and a gas outlet, each having a size of 0.6 mm × 0.2 mm). 6 mm) by 8 × 5 imposition (the imposition pitch was the same as the formation of the fine grooves on the aluminum substrate described above). Thereafter, the cover member was degreased using a degreaser (acetone), and immersed in a zincate bath (bath temperature 20 ° C.) having the following composition for 60 seconds to perform a first zincate treatment. Next, the cover member was washed with water and immersed in a 50% aqueous nitric acid solution (liquid temperature 20 ° C.) for 30 seconds to remove the zinc thin film formed by the first zincate treatment. Next, the cover member was washed with water, immersed in the above-described zincate bath (bath temperature 20 ° C.) for 30 seconds, subjected to a second zincate treatment to form a zinc thin film, and then washed with water. (The above is the surface treatment process)
(Zincate bath composition)
・ Zinc oxide… 20g / L
・ Sodium hydroxide… 120g / L
・ Ferric chloride… 2g / L
・ Rossell salt… 50g / L
・ Sodium nitrate 1g / L
[0037]
Next, the cover member was diffusion bonded to the aluminum substrate surface under the following condition 1. In this diffusion bonding, positioning was performed so that each opening of the cover member coincided with both ends of the flow path of the fine groove formed in the aluminum substrate.
(Diffusion bonding condition 1)
-Atmosphere: in vacuum-Bonding temperature: 300 ° C
・ Joining time: 8 hours ・ Joining pressure: 50 kg / cm ²
[0038]
As a result, the microreactor of the present invention was obtained. As a result of confirming the joining state between the aluminum substrate and the cover member of the obtained microreactor with a scanning ultrasonic image search device (SAT), the joining was performed with extremely high strength, and a multi-faced (8 × 5 face-up) ) It was confirmed that the pitch accuracy was maintained.
[0039]
[Comparative example]
First, in the same manner as in the example, through the groove forming step, the insulating film forming step, the heating element disposing step, and the catalyst supporting step, finally, the fine groove forming surface side of the 8 × 5 imposed aluminum substrate is coated with alumina powder. Polishing exposed the aluminum surface.
Next, an aluminum plate (250 mm × 250 mm) having a thickness of 100 μm was prepared as a cover member, and openings (two raw material inlets and gas outlets, each opening having a size of 0.6 mm × 0.2 mm) were formed in this aluminum plate. 6 mm) by 8 × 5 imposition (the imposition pitch was the same as the formation of the fine grooves on the aluminum substrate described above). Then, this cover member was diffusion-bonded to the aluminum substrate surface under the same bonding conditions as in the example. In this diffusion bonding, positioning was performed so that each opening of the cover member coincided with both ends of the flow path of the fine groove formed in the aluminum substrate. Thereby, a microreactor of a comparative example was obtained.
[0040]
The bonding state between the aluminum substrate and the cover member of the obtained microreactor was confirmed by the same method as in the example. As a result, in the microreactor joined under the same joining condition 1 as in the example, it was confirmed that the aluminum substrate and the cover member peeled off, and a sufficient joining state was not obtained.
[0041]
【The invention's effect】
As described in detail above, according to the present invention, the metal substrate constituting the microreactor is made of aluminum or an aluminum alloy, and has a higher heat conductivity and a smaller heat capacity than a silicon substrate or a ceramic substrate. Heat transfer is performed with high efficiency, and a reforming unit for hydrogen production that has a high rising speed when starting from a stopped state and has a high use efficiency of electric power supplied to the heating element can be provided. In addition, since the both are firmly joined by a surface treatment layer interposed between the metal substrate and the cover member, the microreactor has excellent mechanical stability. Since processing by a micro machine is not required and the processing can be easily performed by an inexpensive processing method such as etching, the manufacturing cost of the microreactor can be reduced.
[Brief description of the drawings]
FIG. 1 is a perspective view showing one embodiment of a microreactor of the present invention.
FIG. 2 is an enlarged vertical sectional view taken along line II-II of the microreactor shown in FIG.
FIG. 3 is a perspective view showing a fine groove portion forming surface side of a metal substrate of the microreactor shown in FIG. 1;
FIG. 4 is a longitudinal sectional view corresponding to FIG. 2, showing another embodiment of the microreactor of the present invention.
FIG. 5 is a process chart for explaining one embodiment of the microreactor manufacturing method of the present invention.
FIG. 6 is a process chart for explaining one embodiment of the microreactor manufacturing method of the present invention.
FIG. 7 is a process chart for explaining another embodiment of the microreactor manufacturing method of the present invention.
FIG. 8 is a process chart for explaining another embodiment of the microreactor manufacturing method of the present invention.
[Explanation of symbols]
1, 1 ': microreactor 2, 2': metal substrate 3: fine groove 4: insulating film (metal oxide film)
4 'insulating film 5 heating element 6 electrode 7 heating element protection layer 8 cover member 9 surface treatment layer C catalyst

Claims (11)

In a microreactor for reforming the raw material to obtain hydrogen gas,
A metal substrate made of aluminum or an aluminum alloy having a fine groove on one surface, a catalyst supported in the fine groove, and a raw material inlet and a gas outlet joined to the metal substrate so as to cover the fine groove; Wherein the cover member is made of any one of aluminum and an aluminum alloy, and has a surface treatment layer at least on a bonding surface with the metal substrate. The microreactor according to claim 1, wherein the surface treatment layer included in the cover member contains at least one of zinc, tin, gold, and copper. 3. The microreactor according to claim 1, wherein the metal substrate includes a heating element on a surface opposite to the surface on which the fine groove is formed, with an insulating film interposed therebetween. 4. The microreactor according to claim 3, wherein the insulating film is a metal oxide film formed by anodizing the metal substrate. The microreactor according to claim 4, wherein the metal oxide film is formed also in the fine groove. The microreactor according to any one of claims 3 to 5, further comprising a heating element protection layer provided so as to expose an electrode of the heating element and cover the heating element. In a method for producing a microreactor for reforming a raw material to obtain hydrogen gas,
A groove forming step of forming a fine groove on one surface of a metal substrate made of aluminum or an aluminum alloy,
A catalyst supporting step of supporting a catalyst in the fine groove portion,
A surface treatment step of forming a surface treatment layer on at least a surface of the cover member made of aluminum or an aluminum alloy formed with a material introduction port and a gas discharge port, the surface being joined to the metal substrate,
A bonding step of diffusing and bonding the cover member to the metal substrate so as to cover the microgrooves. The method according to claim 7, wherein the surface treatment step is a step of forming a thin film containing at least one of zinc, tin, gold, and copper. The method for manufacturing a microreactor according to claim 7, wherein the surface treatment step is a double zincate treatment. An insulating film forming step of providing an insulating film on at least the metal substrate surface on which the fine groove is not formed, between the groove forming step and the catalyst supporting step, and a heating element providing a heating element on the insulating film The method for producing a microreactor according to any one of claims 7 to 9, further comprising an arrangement step. The method according to claim 10, wherein the insulating film forming step is a step of forming a metal oxide film by anodizing the metal substrate.

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