JP4928491B2 - Manufacturing method of microreactor - Google Patents

Description

  The present invention relates to a method for manufacturing a microreactor, and more particularly, to a method for manufacturing a microreactor for reforming a hydrocarbon fuel to generate hydrogen.

Conventionally, a reactor utilizing a catalyst has been used in various fields, and an optimum design is made according to the purpose.
On the other hand, in recent years, attention has been focused on using hydrogen as a fuel because no global warming gas such as carbon dioxide is generated and the energy efficiency is high from the viewpoint of protecting the global environment. In particular, fuel cells are attracting attention because they can directly convert hydrogen into electric power and have high energy conversion efficiency in a cogeneration system that uses generated heat. Up to now, fuel cells have been adopted under special conditions such as space development and marine development, but recently they have been developed for use in automobiles and household distributed power supplies, and fuel cells for portable devices have also been developed. ing.
Miniaturization is indispensable for fuel cells for portable devices, and various attempts have been made to reduce the size of reformers that produce hydrogen gas by steam reforming hydrocarbon fuels. For example, various microreactors have been developed in which a channel is formed in a metal substrate, a silicon substrate, a ceramic substrate, etc., and a catalyst is supported in the channel (Patent Document 1).

Among such microreactors, for example, a microreactor using a stainless steel substrate as a metal substrate is cheaper than a case where a silicon substrate is used, and is in line with a demand for manufacturing cost reduction. However, in the manufacture of microreactors using a stainless steel substrate, diffusion bonding is used in the process of forming the flow path by bonding the substrates, and in order to prevent the catalyst from being deactivated due to high temperature and high pressure conditions in this diffusion bonding. In addition, it is necessary to support the catalyst in the flow path after the flow path is formed.
As this catalyst loading method, for example, a metal hydroxide to be a catalyst is produced by a coprecipitation method, and this is filtered and dried to disperse the produced metal oxide in a silica sol to form a metal source sol. There is a method (gas phase reduction method) in which a sol is poured into a flow channel and attached to the wall surface of the flow channel to remove excess sol, and then converted into a catalytic metal by gas phase reduction using hydrogen (Non-Patent Document 1). .
In addition, as a catalyst loading method, a solution containing a metal acetate and urea as a catalyst is poured into the flow path, and the pH of the solution becomes alkaline due to ammonia generated by the decomposition of urea, so that There is a method (urea decomposition method) in which a metal oxide is precipitated, and then an excess solution is removed, dried (heat treatment), and reduced to a catalytic metal (Patent Document 2).
JP 2002-252014 A 2006 Fuel Cell Seminar “Development of Hydrogen-Generator for mobile applications” Takeshi Kihara, Hiroshi Yagi JP 2002-79100 A

However, in the gas phase reduction method as described above, agglomeration is likely to occur at the stage of dispersing the metal oxide in the silica sol to form the metal source sol and the stage of gas phase reduction, and the catalyst fine particles and uniform distribution are hindered. There was a problem that the performance of the catalyst deteriorated. Further, the above urea decomposition method also has a problem that the catalyst metal is easily aggregated during the reduction, resulting in a decrease in the performance of the catalyst.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a manufacturing method that enables the manufacture of a microreactor with high efficiency of a reforming reaction for generating hydrogen from a hydrocarbon fuel. And

  In order to achieve such an object, the present invention provides a groove portion forming step for forming a fine groove portion on one surface of at least one metal substrate of a set of metal substrates, and a catalyst for forming a catalyst support layer in the fine groove portion. A raw material introduction port and a gas discharge port communicated with the tunnel-shaped flow path provided inside the tunnel-shaped flow path constituted by the fine groove portions by bonding the support layer forming step and the set of metal substrates. And a catalyst supporting step for supporting a Cu-Zn-based catalyst on the catalyst supporting layer in the tunnel-shaped flow path, and the catalyst supporting step includes a Cu precursor. A precursor solution containing a body in a concentration range of 10 to 200 mmol / L, a Zn precursor in a concentration range of 5 to 100 mmol / L, and a reducing agent in a concentration of 20 to 400 mmol / L is placed in the tunnel-shaped channel. filling , Subjected to a heat treatment to the precursor solution in this state, then the configuration to remove the precursor solution from the tunnel-shaped passage.

As another aspect of the present invention, the Cu precursor and the Zn precursor are configured to be at least one of acetate, acesylacetonate, and nitrate.
As another aspect of the present invention, the reducing agent is configured to be at least one of hydrazine and sodium borohydride.
As another aspect of the present invention, the heat treatment is configured such that the temperature is in the range of 50 to 100 ° C. and the treatment time is in the range of 30 to 120 minutes.
As another aspect of the present invention, the heat treatment is performed by blowing warm air to heat the joined body, or a heating element is provided on the outer wall surface of the joined body, It was set as the structure performed by energizing and heating a conjugate | zygote.
As another aspect of the present invention, a stainless steel substrate is used as the metal substrate, and diffusion bonding is performed in the bonding step.

In the present invention, the precursor solution is heat-treated in a state where it is filled in the tunnel-shaped flow path, and the Cu precursor and the Zn precursor in the precursor solution are reduced by the reducing agent, so that a Cu-Zn-based catalyst is obtained. Since it is generated and supported on the catalyst support layer, the aggregation of the catalyst is suppressed and the Cu-Zn catalyst in the form of fine particles can be uniformly supported, and a microreactor with high reaction efficiency can be manufactured.
Moreover, by making Cu precursor and Zn precursor at least one of acetate, acesylacetonate, and nitrate, the solubility of Cu precursor and Zn precursor in the precursor solution can be increased, A larger amount of precursor can be introduced into the tunnel-like flow path to increase the amount of catalyst supported.

Embodiments of the present invention will be described below with reference to the drawings.
First, an example of a microreactor manufactured by the microreactor manufacturing method of the present invention will be described. FIG. 1 is a perspective view showing an example of a microreactor, and FIG. 2 is an enlarged longitudinal sectional view taken along line AA of the microreactor shown in FIG. 1 and 2, the microreactor 1 includes a metal substrate 4 having a fine groove portion 5 formed on one surface 4a and a metal substrate 6 having a fine groove portion 7 formed on one surface 6a. And the joined body 2 joined so that the fine groove part 7 may oppose. Inside the joined body 2, a tunnel-like flow path 3 composed of opposing fine groove portions 5 and 7 is formed, and the entire inner wall surface of the tunnel-like flow path 3 is interposed via a catalyst support layer 9. A Cu—Zn-based catalyst C is supported. A heating element 11 is provided on one surface of the joined body 2 (the surface of the metal substrate 4) via an insulating layer 10, and electrodes 12 and 12 are provided on both ends of the heating element 11. ing.

  FIG. 3 is a perspective view showing a state in which the metal substrate 4 and the metal substrate 6 constituting the joined body 2 of the microreactor 1 shown in FIG. 1 are separated from each other. In FIG. 3, the catalyst support layer 9 is omitted. As shown in FIG. 3, the fine groove portions 5 and 7 are formed in a continuous shape while being meandering by folding back 180 degrees. And the fine groove part 5 and the fine groove part 7 are pattern shapes which are symmetrical with respect to the joint surface of the metal substrates 4 and 6. Therefore, by joining the metal substrates 4 and 6, the end 5 a of the fine groove 5 is located on the end 7 a of the fine groove 7, and the end 5 b of the fine groove 5 is located on the end 7 b of the fine groove 7. Thus, the fine groove portion 5 and the fine groove portion 7 are completely opposed to each other. As shown in FIG. 1, the end portions of the tunnel-like flow path 3 constituted by the fine groove portions 5 and 7 serve as a raw material introduction port 8a and a gas discharge port 8b. In addition, the positions of the raw material inlet 8a and the gas outlet 8b of the microreactor 1 are not limited to the illustrated example. Further, a connection member or the like having a desired shape may be disposed at the raw material introduction port 8a and the gas discharge port 8b.

Since the metal substrates 4 and 6 constituting the microreactor 1 do not carry the catalyst C directly on the wall surface of the tunnel-shaped flow path 3, a metal material that allows easy processing of the fine grooves 5 and 7 and is easy to join is selected. For example, it may be a stainless steel substrate, a copper substrate, an aluminum substrate, a titanium substrate, an iron substrate, an iron alloy substrate, or the like. In the case of a stainless steel substrate or a copper substrate, precise processing of the fine groove portions 5 and 7 is easy, and a strong joined body 2 can be obtained by diffusion bonding, welding, and brazing. The thicknesses of the metal substrates 4 and 6 can be appropriately set in consideration of the size of the microreactor 1, the heat capacity of the metal used, the characteristics such as the thermal conductivity, the size of the fine groove portions 5 and 7 to be formed, and the like. However, it can set in the range of about 50-5000 micrometers, for example.
The fine groove portions 5 and 7 formed in the metal substrates 4 and 6 are not limited to the shape as shown in FIG. 3, and the amount of the catalyst C carried in the fine groove portions 5 and 7 increases, and The flow path where the raw material comes into contact with the catalyst C can have an arbitrary shape. Further, the shape of the inner wall surface of the fine groove portions 5 and 7 in the cross section perpendicular to the fluid flow direction of the tunnel-shaped flow path 3 is preferably an arc shape, a semicircular shape, or a U shape. The diameter of the tunnel-like flow path 3 composed of such fine groove portions 5 and 7 can be set, for example, within a range of about 100 to 2000 μm, and the flow path length can be set within a range of about 30 to 300 mm. .

The catalyst support layer 9 can be an inorganic oxide film, for example, an alumina (Al ₂ O ₃ ) film, a mullite (Al ₂ O ₃ .2SiO ₂ ) film, a silica (SiO ₂ ) film formed by thermal spraying, A zirconia (ZrO ₂ ) film, a titania (TiO ₂ ) film, a ceria (CeO ₂ ) film, or the like can be used. The thickness of such a catalyst-carrying layer 9 can be appropriately set within a range of about 10 to 50 μm, for example.
The insulating layer 10 is made of, for example, one or more of polyimide, aluminum oxide (Al ₂ O ₃ ), silicon oxide (SiO ₂ ), zirconium oxide, magnesium oxide, silicon nitride, aluminum nitride, and the like. it can. Such an insulating layer 10 can be formed by, for example, dry film formation such as screen printing, sputtering, CVD, PVD, and AD, or wet film formation such as a sol-gel method and a chemical solution method. . The thickness of the insulating layer 10 can be set in the range of 0.1 to 5 μm, preferably 0.5 to 1 μm.

The heating element 11 is for supplying heat necessary for reforming the hydrocarbon fuel, which is an endothermic reaction, and is made of carbon paste, nichrome (Ni—Cr alloy), W, Mo, Au, Ti, or the like. Can be used. As shown in FIG. 1, the heating element 11 draws a thin wire having a width of about 10 to 200 μm over the entire region on the metal substrate 4 (insulating layer 10) corresponding to the region where the fine groove portion 5 is formed. Although it can be set as such a shape, it is not limited to such a shape and can be set suitably.
The energization electrodes 12, 12 formed on the heating element 11 can be formed using a conductive material such as Au, Ag, Pd, Pd—Ag, and are made of the same material as the heating element 11. There may be.
For the purpose of protecting the heating element 11, a protective layer covering the heating element 11 may be provided. In this case, the protective layer can be formed of, for example, a ceramic material such as Al ₂ O ₃ or SiO ₂ , photosensitive polyimide, varnish-like polyimide, or the like. In addition, the thickness of the protective layer can be appropriately set in consideration of the material to be used, but can be set, for example, in the range of about 2 to 25 μm.

Next, the manufacturing method of the microreactor of this invention is demonstrated.
4 and 5 are process diagrams for explaining an embodiment of the microreactor manufacturing method of the present invention. 4 and 5, the above-described microreactor 1 will be described as an example.
In the manufacturing method of the present invention, first, in the groove portion forming step, the fine groove portion 5 is formed on the one surface 4a of the metal substrate 4, and the fine groove portion 7 is formed on the one surface 6a of the metal substrate 6 (FIG. 4A). )). The fine groove portions 5 and 7 are formed by forming resist patterns 41 and 42 having predetermined opening patterns on the surfaces 4a and 6a of the metal substrates 4 and 6, and using the resist patterns 41 and 42 as a mask by wet etching. 6 can be formed by etching.
The pattern shapes of the fine groove portions 5 and the fine groove portions 7 formed on the metal substrates 4 and 6 are shapes that are plane-symmetric with respect to the joint surfaces (4a and 6a) of the metal substrates 4 and 6. Further, the fine groove portions 5 and 7 can have a cross section of an arc shape, a semicircular shape, or a U shape. Since the metal substrates 4 and 6 to be used do not directly carry the catalyst C in the fine groove portions 5 and 7, it is possible to select a metal material that allows easy precision processing of the fine groove portions 5 and 7 and is easy to join. For example, it may be a stainless steel substrate, a copper substrate, an aluminum substrate, a titanium substrate, an iron substrate, an iron alloy substrate, or the like.

Next, in the catalyst support layer forming step, thermal spraying is performed on the joint surfaces 4a and 6a (surfaces on which the fine groove portions 5 and 7 are formed) of the metal substrates 4 and 6 through the resist patterns 41 and 42 described above. A catalyst support layer 9 is formed (FIG. 4B). Thereafter, the resist patterns 41 and 42 are removed, and the unnecessary catalyst supporting layer 9 is removed by lift-off to form the catalyst supporting layer 9 only in the fine groove portions 5 and 7 (FIG. 4C).
Thermal spraying can be performed, for example, by a plasma spray method (using high-temperature plasma, melting the alumina spray powder and spray-coating it on the surface of the substrate). The thickness of such a catalyst-carrying layer 9 can be set in the range of 10 to 50 μm, for example. Further, as described above, since the unnecessary catalyst support layer 9 is lifted off simultaneously with the removal of the resist patterns 41 and 42, a clean bonding surface is secured in the metal substrates 4 and 6.
In addition, you may roughen the wall surface of the fine groove parts 5 and 7 after forming a groove part and before forming a catalyst support layer. The roughening treatment can be, for example, any of sandblasting, etching, and roughening plating. The degree of roughening is, for example, a center line average roughness (R _a ) of 0.2. It can set so that it may become in the range of -2.0 micrometers.

Further, when the resist patterns 41 and 42 do not have resistance to polishing treatment and resistance to thermal spraying, the resist patterns 41 and 42 are removed after the groove portion forming step, and then the openings corresponding to the fine groove portions 5 and 7 are formed. Thermal spraying can be performed through a metal mask having a portion. Alternatively, after removing the resist patterns 41 and 42, a resist pattern having resistance to thermal spraying is formed in a portion where the fine groove portions 5 and 7 of the metal substrates 4 and 6 are not formed, and thermal spraying is performed via the resist pattern. It can also be done. In any case, since the unnecessary catalyst support layer 9 is lifted off, a clean bonding surface is ensured in the metal substrates 4 and 6.
Next, in the joining step, a set of metal substrates 4 and 6 are joined at the surfaces 4a and 6a so that the fine groove portions 5 and the fine groove portions 7 face each other, thereby forming the joined body 2 (FIG. 5A). )).

As described above, since the fine groove portion 5 and the fine groove portion 7 have a pattern shape which is plane-symmetrical via the joint surfaces (4a, 6a) of the metal substrates 4 and 6, the fine groove portions 5 and the fine groove portions 7 The groove 5 and the fine groove 7 are completely opposed to form the tunnel-like flow path 3. The shape of the inner wall surface in a cross section perpendicular to the fluid flow direction of the tunnel-shaped flow path 3 is substantially circular, and the catalyst supporting layer 9 is provided on the entire inner wall surface, and the end portion is connected to the raw material inlet 8a. It becomes the gas discharge port 8b. The metal substrates 4 and 6 can be bonded by diffusion bonding, welding, or brazing, for example, when a stainless steel substrate or a copper substrate is used.
Next, in the catalyst supporting step, a Cu—Zn-based catalyst C is supported on the catalyst supporting layer 9 on the inner wall surface of the tunnel-shaped flow path 3 (FIG. 5B). The catalyst C is supported on the catalyst support layer 9 as follows. First, a precursor solution containing a Cu precursor, a Zn precursor, and a reducing agent is filled into the tunnel-shaped flow path 3 from the raw material inlet 8a or the gas outlet 8b. In this state, the precursor solution is subjected to heat treatment to reduce the Cu precursor and the Zn precursor in the precursor solution with a reducing agent to generate a Cu—Zn-based catalyst, which is supported on the catalyst support layer 9. Let Thereafter, the remaining solution is removed from the tunnel-like flow path 3. In order to maintain the precursor solution filled in the tunnel-like flow path 3, the raw material inlet 8a and the gas outlet 8b are temporarily closed using a polytetrafluoroethylene lid or the like.

  The Cu precursor concentration in the precursor solution is 10 to 200 mmol / L, preferably 50 to 100 mmol / L, the Zn precursor concentration is 5 to 100 mmol / L, preferably 25 to 50 mmol / L, and the reducing agent. The concentration is 20 to 400 mmol / L, preferably 100 to 200 mmol / L. When the Cu precursor is less than 10 mmol / L and the concentration of the Zn precursor is less than 5 mmol / L, a sufficient amount of Cu precursor and Zn precursor cannot be introduced into the tunnel-like flow path 3 and the catalyst is supported. When the amount of Cu precursor exceeds 200 mmol / L or the concentration of Zn precursor exceeds 100 mmol / L, Cu—Zn does not reduce or precipitate, or the inlet of the flow path is blocked. Absent. On the other hand, when the reducing agent concentration is less than 20 mmol / L, the reduction of the Cu precursor and the Zn precursor becomes insufficient and the amount of catalyst supported decreases. On the other hand, when the reducing agent concentration exceeds 400 mmol / L, the reduction reaction occurs. It becomes uncontrollable, and Cu—Zn does not precipitate at an appropriate site, which is not preferable.

As the Cu precursor and the Zn precursor, at least one of acetate, acesylacetonate, and nitrate can be used. Such a precursor can increase the solubility in the precursor solution as compared with, for example, acetylacetonate salt, and introduces more precursor into the tunnel-like channel 3 to increase the amount of catalyst supported. Can be made.
Moreover, at least 1 sort (s) of a hydrazine and sodium borohydride can be used for a reducing agent. Since these reducing agents exhibit a reducing action by heating, it is possible to control the start of the reduction reaction of the Cu precursor and the Zn precursor in the precursor solution filled in the tunnel-like flow path 3.
In the present invention, alumina powder may be contained in the precursor solution. Thereby, the Cu-Zn-based catalyst generated by reducing the Cu precursor and the Zn precursor is supported on the alumina powder together with the catalyst supporting layer 9, and the alumina powder is also incorporated into the catalyst supporting layer 9 by the catalyst network, The catalyst carrying area is substantially increased.

The heat treatment conditions applied to the precursor solution with the precursor solution filled in the tunnel-like flow path 3 are used so that the reduction reaction of the Cu precursor and the Zn precursor in the precursor solution can be performed reliably. The temperature can be appropriately set in consideration of the Cu precursor or Zn precursor and the reducing agent. For example, the temperature is in the range of 50 to 100 ° C., preferably in the range of 80 to 90 ° C., and the treatment time is 30 to 120 minutes, preferably 50 The range is ˜80 minutes. Such heat treatment can be performed by heating the bonded body 2 by blowing hot air. Alternatively, the heating element 11 as described below may be formed before the catalyst supporting step, and the precursor solution may be heat-treated by energizing the heating element 11 and heating the joined body 2.
Next, the insulating layer 10 is formed on the surface 4b of the metal substrate 4 constituting the bonded body 2, and the heating element 11 is formed on the insulating layer 10 (FIG. 5C). Thereby, the microreactor 1 is obtained.
The insulating layer 10 can be formed by a dry film forming method such as a screen printing method, a sputtering method, a CVD method, a PVD method, or an AD method, or a wet film forming method such as a sol-gel method or a chemical solution method.

In the microreactor manufacturing method as described above, the precursor solution is subjected to heat treatment while being filled in the tunnel-like flow path 3, and the Cu precursor and the Zn precursor in the precursor solution are reduced by the reducing agent. Thus, a Cu—Zn-based catalyst is generated and supported on the catalyst support layer 9. Therefore, the aggregation of the catalyst is suppressed and the Cu-Zn-based catalyst C in the form of fine particles can be uniformly supported, and a microreactor with high reaction efficiency can be manufactured.
In addition, each embodiment of the above-mentioned microreactor manufacturing method is an illustration, and this invention is not limited to these.

Next, the present invention will be described in more detail by showing more specific examples.
[Example 1]
<Groove formation process>
A SUS316L substrate (25 mm × 25 mm) having a thickness of 1 mm is prepared as a metal substrate, and a photosensitive resist material (OFPR manufactured by Tokyo Ohka Kogyo Co., Ltd.) is applied to both surfaces of the SUS316L substrate by a dipping method (film thickness 7 μm (when dry)) )did. Next, a photomask having a shape in which stripe-shaped light-shielding portions having a width of 2000 μm alternately protrude from the left and right (projection length 20 mm) on the resist coating film on the side where the fine groove portions of the SUS316L substrate are to be formed was disposed. Also, a SUS316L substrate similar to that described above was prepared, a photosensitive resist material was applied in the same manner, and a photomask was placed on the resist coating film on the side where the fine groove portion of the SUS316L substrate was to be formed. This photomask is symmetrical with the above photomask with respect to the SUS316L substrate surface.

Next, the resist coating film was exposed through a photomask for each of the above set of SUS316L substrates, and developed using a sodium hydrogen carbonate solution. As a result, a resist pattern in which stripe-like openings having a width of 2000 μm are arranged at a pitch of 2500 μm on one surface of each SUS316L substrate and adjacent stripe-like openings are alternately continued at the end portions thereof. Been formed.
Next, using the resist pattern as a mask, the SUS316L substrate was etched (for 3 minutes) under the following conditions.
(Etching conditions)
・ Temperature: 50 ℃
・ Etching solution (ferric chloride solution) Specific gravity concentration: 45 Baume (° B'e)

  As a result, a pair of SUS316L substrates are formed with stripe-shaped fine grooves having a width of 2000 μm, a depth of 650 μm, and a length of 20 mm on one surface thereof at a pitch of 2500 μm, and alternately at the ends of adjacent fine grooves. A fine groove part (flow path length: 220 mm) having a continuous shape (a shape meandering and continuous while being folded by 180 degrees as shown in FIG. 3) was formed. The shape of the inner wall surface in a cross section perpendicular to the fluid flow direction of the fine groove portion was substantially semicircular.

<Catalyst support layer forming step>
As described above, alumina spraying was performed by a plasma spray method on the fine groove forming surface of the pair of SUS316L substrates on which the fine groove was formed.
Next, the resist pattern was removed using a sodium hydroxide solution and washed with water. By removing the resist pattern, the unnecessary alumina sprayed film was lifted off, and a catalyst supporting layer (thickness 30 μm) made of the alumina sprayed film was formed only in the fine groove portion.

<Joint process>
Subsequently, the above-mentioned set of SUS316L substrates was diffusion bonded under the following conditions so that the fine groove portions were opposed to each other to produce a joined body. In this bonding, alignment was performed so that the fine groove portions of one set of substrates completely face each other. As a result, a tunnel-like flow path in which the raw material introduction port and the gas discharge port exist on the opposing end surfaces of the joined body was formed in the joined body.
(Diffusion bonding conditions)
-Atmosphere: in vacuum-Joining temperature: 1000 ° C
-Joining time: 12 hours

<Catalyst loading process>
Next, a precursor solution having the following composition is injected into the tunnel-shaped channel of the joined body, and the raw material inlet and the gas outlet located on the end face of the tunnel-shaped channel are made of polytetrafluoroethylene (Teflon manufactured by DuPont). Temporary occlusion was performed using a lid. In the following composition display, (OAc) ₂ represents acesylacetonate, and the same applies to the following description.
(Composition of precursor solution)
Cu (OAc) ₂ (Cu precursor) ... 100 mmol / L
・ Zn (OAc) ₂ (Zn precursor): 50 mmol / L
・ Alumina powder (γ-Al ₂ O ₃ ) 4% by weight
・ Hydrazine (reducing agent): 200mmol / L
・ Water: 15mL

  Preparation and injection of the precursor solution were performed as follows. First, in a 50 mL beaker, Cu precursor and Zn precursor were dissolved in 5 mL of ion exchange water, and alumina powder was added (preparation of aqueous metal source solution). In another beaker, hydrazine was dissolved in 5 mL of ion-exchanged water (preparation of reducing agent aqueous solution). Both beakers were cooled to 0 ° C. using a cooler and stirred with a stirrer. Next, a reducing agent aqueous solution was poured into a beaker containing a metal source aqueous solution, and both aqueous solutions were mixed to form a precursor solution, which was quickly collected using a syringe and injected into a microreactor. Next, with the microreactor plugged, it was kept at 90 ° C. for 1 hour with a hot air dryer to carry out a reduction reaction. Thereafter, the stopper was removed and the catalyst was supported at 103 ° C. for 1 hour by scattering the solvent.

Next, a SiO ₂ precursor (Aquamica manufactured by AZ Electronic Materials Co., Ltd.) is applied as a coating solution for an insulating layer on one SUS316L substrate constituting the above-mentioned bonded body, and cured at 350 ° C. Thus, an insulating layer having a thickness of 1.0 μm was formed. Next, a heating element having the following film configuration was formed on the insulating layer by sputtering using a metal mask. The formed heating element was shaped to have a line width of 100 μm and drawn around at a line interval of 100 μm so as to be folded 180 ° as shown in FIG.
(Film structure of heating element)
・ Cr: 0.01μm
・ Ni: 0.03μm
・ Au ... 0.15μm

Next, a hot melt material was applied to the electrode portion on the heating element, and the same SiO ₂ precursor (Aquamica manufactured by AZ Electronic Materials Co., Ltd.) used for forming the insulating layer was applied by spin coating. . Then, while hardening at 350 degreeC, the hot-melt material was removed and the protective layer of the shape where the electrode part opened was formed.
As a result, a microreactor (outer dimensions 25 mm × 25 mm × about 2.1 mm) was produced.

[Examples 2 to 7]
The composition of the precursor solution used in the catalyst supporting step was the same as in Example 1 except that the concentrations of copper acetate monohydrate, zinc acetate dihydrate, and hydrazine were set as shown in Table 1 below. A microreactor was prepared.
[Comparative Examples 1-6]
The composition of the precursor solution used in the catalyst supporting step was the same as in Example 1 except that the concentrations of copper acetate monohydrate, zinc acetate dihydrate, and hydrazine were set as shown in Table 1 below. A microreactor was prepared.

[Comparative Example 7]
A microreactor was produced in the same manner as in Example 1 except that the catalyst supporting step was performed as follows.
<Catalyst loading process>
A precursor solution having the following composition is injected into the tunnel-like channel of the joined body, and a raw material inlet and a gas outlet located at the end face of the tunnel-like channel are covered with polytetrafluoroethylene (Teflon manufactured by DuPont). Temporarily blocked.
(Composition of precursor solution)
Cu (OAc) ₂ (Cu precursor) 150 mmol / L
・ Zn (OAc) ₂ (Zn precursor): 75 mmol / L
・ Urea ... 600mmol / L
・ Water: 10mL

  The precursor solution was prepared by simultaneously dissolving a Cu precursor, a Zn precursor, and urea in ion exchange water. This precursor solution was injected into the microreactor using a syringe, and the microreactor was capped. In this state, the temperature was maintained at 90 ° C. for 27 hours with a hot air dryer to perform a urea decomposition reaction. Thereafter, the stopper was removed and the mixture was kept at 103 ° C. for 1 hour to scatter the solvent. Finally, the catalyst was supported by firing at 300 ° C. under a flow of Ar (60 mL / min).

[Evaluation]
Using the produced microreactors (Examples 1 to 7 and Comparative Examples 1 to 7), methanol steam reforming experiments were performed under the following conditions, the methanol conversion was measured, and the results are shown in Table 1 below.
(Methanol steam reforming conditions)
-Reactant flow rate: 0.05 mL / min-Heating element temperature: 300 ° C

  The present invention can be used for hydrogen production by reforming hydrocarbon fuels.

It is a perspective view which shows an example of the microreactor manufactured with the manufacturing method of the microreactor of this invention. It is an expanded longitudinal cross-sectional view in the AA line of the microreactor shown by FIG. It is a perspective view which shows the state which spaced apart the metal substrate which comprises the microreactor shown by FIG. It is process drawing for demonstrating one Embodiment of the microreactor manufacturing method of this invention. It is process drawing for demonstrating one Embodiment of the microreactor manufacturing method of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Microreactor 2 ... Assembly 3 ... Tunnel-shaped flow path 4, 6 ... Metal substrate 5, 7 ... Fine groove part 8a ... Raw material introduction port 8b ... Gas discharge port 9 ... Catalyst support layer 10 ... Insulating layer 11 ... Heating body C …catalyst

Claims (7)

A groove forming step of forming a fine groove on one surface of at least one metal substrate of the set of metal substrates;
A catalyst support layer forming step of forming a catalyst support layer in the fine groove,
By joining the set of metal substrates, a joined body having a tunnel-like flow path constituted by the fine groove portion and having a raw material introduction port and a gas discharge port communicated with the tunnel-like flow path is provided. A bonding process to be formed;
A catalyst supporting step of supporting a Cu-Zn-based catalyst on the catalyst supporting layer in the tunnel-shaped flow path,
The catalyst supporting step includes a precursor solution containing a Cu precursor in a concentration range of 10 to 200 mmol / L, a Zn precursor in a concentration range of 5 to 100 mmol / L, and a reducing agent in a concentration of 20 to 400 mmol / L. In the tunnel-shaped flow path, heat-treating the precursor solution in this state, and then removing the precursor solution from the tunnel-shaped flow path.   The method for producing a microreactor according to claim 1, wherein the Cu precursor and the Zn precursor are at least one of acetate, acesylacetonate, and nitrate.   The method for producing a microreactor according to claim 1, wherein the reducing agent is at least one of hydrazine and sodium borohydride.   The method of manufacturing a microreactor according to any one of claims 1 to 3, wherein the heat treatment has a temperature in a range of 50 to 100 ° C and a treatment time in a range of 30 to 120 minutes.   The method for manufacturing a microreactor according to any one of claims 1 to 4, wherein the heat treatment is performed by blowing hot air to heat the joined body.   5. The heat treatment is performed by providing a heating element on an outer wall surface of the joined body and energizing the heating element to heat the joined body. 6. Manufacturing method of microreactor.   The method for manufacturing a microreactor according to any one of claims 1 to 6, wherein a stainless steel substrate is used as the metal substrate, and diffusion bonding is performed in the bonding step.

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