JP2011050925A - Hydrogen catalyst member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydrogen catalyst member which can reduce a weight thereof, can be miniaturized, has high design flexibility and is optimally configured in accordance with heat circumstances in a hydrogen supply device, in the hydrogen catalyst member which performs dehydrogenation for taking out hydrogen or performing hydrogen addition for taking in hydrogen by using a medium which repeats chemically hydrogen storage and supply by means of catalyst carrier prepared by carrying a metal catalyst onto a porous oxide made by anodization. <P>SOLUTION: The porous oxide film is formed on the surface of an aluminum foil subjected to rugging process; the metal catalyst is deposited onto the porous oxide film; and thereafter, the foil is laminated or wound to obtain the hydrogen catalyst member. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a hydrogen catalyst member that performs dehydrogenation and hydrogen addition, and more particularly to a hydrogen catalyst member that uses a catalyst carrier in which a metal catalyst is supported on a porous oxide film.

  In recent years, organic hydride systems using hydrocarbons such as cyclohexane and decalin have attracted attention as hydrogen storage methods that are excellent in safety, transportability and storage capacity. Since these hydrocarbons are liquid at room temperature, they are excellent in transportability.

  For example, benzene and cyclohexane are cyclic hydrocarbons having the same carbon number, but benzene is an unsaturated hydrocarbon in which the bonds between carbons are double bonds, whereas cyclohexane is a saturated hydrocarbon having no double bonds. Hydrogen. Cyclohexane is obtained by the hydrogenation reaction of benzene, and benzene is obtained by the dehydrogenation reaction of cyclohexane. That is, hydrogen can be stored and supplied by utilizing hydrogenation and dehydrogenation of these hydrocarbons.

  By the way, Patent Document 1 discloses a medium in which the surface of an aluminum plate is anodized, a porous oxide film is provided, a metal catalyst is supported on the porous oxide film as a catalyst carrier, and hydrogen storage and supply are chemically repeated. It has been proposed to obtain a dehydrogenation catalyst member for taking out hydrogen by using the above. It has also been proposed to improve the efficiency of hydrogen separation by stacking the aluminum flat plate dehydrogenation catalyst members via spacers.

JP 2007-326000 A

It is necessary to design the hydrogen reaction vessel in accordance with the hydrogen reaction system for taking out hydrogen, and to design the hydrogen catalyst member to be put in the hydrogen reaction vessel accordingly.
In Patent Document 1 in which a porous oxide film is provided on an aluminum flat plate, the thermal diffusion from the heat exchanger relies on the thermal conductivity of the aluminum flat plate. Here, in order to increase the volume ratio of the catalyst carrier, it is necessary to increase the thickness of the porous oxide film. However, since the porous oxide film has poor thermal conductivity, if the porous oxide film is too thick, the hydrogen conversion rate is reversed. descend. In addition, when the porous oxide film is thick, the pores of the porous oxide film become longer and the surface area increases, but in the dehydrogenation or hydrogenation reaction, the hydrogen medium and hydrogen must be exchanged in the pores. In the case of pores, the exchange efficiency deteriorates.
In other words, the aluminum metal part having high thermal conductivity and the porous oxide film part having low thermal conductivity need to be thin and densely configured, and a gap such as a gas flow path must also be configured. In a laminated structure, there is a limit to thinning in order to maintain strength.
As described above, with the conventional technology, it is difficult to obtain a small and lightweight hydrogen supply device.

In order to solve the above-mentioned problems, the present invention is easy to handle, has a high degree of freedom in design, and is optimally suited to the state of heat conduction in the hydrogen supply device while realizing weight reduction and downsizing. A catalyst member is provided.

In order to solve the above problems, the present invention provides the following hydrogen catalyst member.
(1) In a hydrogen catalyst member that performs dehydrogenation to extract hydrogen or hydrogen addition to take in hydrogen using a catalyst carrier in which a metal catalyst is supported on a porous oxide film, which repeatedly repeats hydrogen storage and supply, The present invention provides a hydrogen catalyst member in which a porous oxide film is provided on the surface of a processed aluminum foil, and is laminated or wound.
(2) In said (1), the said aluminum foil provides the hydrogen catalyst member characterized by carrying out the uneven | corrugated process by embossing.
(3) In the above (1) or (2), the aluminum foil includes a penetrating hole, and provides a hydrogen catalyst member.
(4) In the above (1), (2), or (3), there is provided a hydrogen catalyst member, wherein the aluminum foil is provided with a hole whose surface is roughened in a tunnel shape from the surface by etching. Is.

  According to the present invention, by providing a porous oxide film on the surface of an unevenly processed aluminum foil and using a hydrogen catalyst member laminated or wound, it is easy to handle while realizing weight reduction and miniaturization, The degree of design freedom is high, and an optimal hydrogen catalyst member can be provided in accordance with the state of heat conduction in the hydrogen supply apparatus.

It is the hydrogen catalyst member of Example 1 of this invention, and shows the case where embossing is carried out to foil and winding. It is the hydrogen catalyst member of Example 2 of this invention, and has shown the case where a flat foil is laminated | stacked and wound on a corrugated foil. It is a hydrogen catalyst member of Example 3 of the present invention, and shows a case where a hole is formed in a foil with a thing like a quadrangular pyramid, and a convex part of a hole burr is provided in the foil. The schematic of the hydrogen catalyst member of this invention and the hydrogen reaction unit using the same is shown.

The porous oxide film described in the present invention is composed of a porous oxide film among oxide films formed by anodizing aluminum.
As an anodic oxidation method for forming a porous oxide film, for example, phosphoric acid, chromic acid, oxalic acid, sulfuric acid, citric acid, malonic acid, an aqueous tartaric acid solution, or the like can be used as the electrolytic solution.
The diameter of the pores formed by anodization, the interval between the pores, and the film thickness can be appropriately set according to conditions such as applied voltage, processing temperature, and processing time.
The pore diameter of the porous oxide film is 1 nm or more, and is adjusted according to the size of the supported metal catalyst. However, when trying to enlarge the pore diameter only under chemical conversion conditions, the pore spacing may be widened and the optimum catalyst loading density may not be obtained. Therefore, the pore diameter in anodization remains small, and the subsequent acidic solution treatment is performed. It is good to adjust the pore diameter.

  The treatment liquid temperature for anodization is preferably 0 ° C. to 50 ° C., particularly 30 ° C. to 40 ° C. Further, the treatment time of this anodic oxidation differs depending on the treatment conditions and the thickness of the porous oxide film to be formed. For example, in the case of 15 V for 40 minutes at 20 ° C. and 4 mass% oxalic acid aqueous solution, it is about 1.5 μm. A thick anodized layer can be formed.

Further, it is desirable to perform the following acid (or alkali) aqueous solution treatment, boehmite treatment, firing treatment, and metal catalyst supporting treatment.
The acid (or alkali) aqueous solution treatment is intended to enlarge the diameter of the formed pores. For example, in the case of phosphoric acid, it is preferably 5% by mass to 20% by mass, and 10 ° C. to 30 ° C. Treatment is performed for 10 minutes to 2 hours until the pore diameter is appropriately expanded.
The purpose of boehmite treatment is to form feathered aluminum hydroxide on the surface of the porous oxide film, and is performed in water at pH 6 to pH 8, preferably pH 7 to pH 8, and at 90 to 100 ° C. under atmospheric pressure. The treatment is performed for 1 hour or longer, preferably 5 hours or longer. Moreover, if a pressurized container is used and the temperature is 100 ° C. or higher, the processing time can be shortened.
The firing treatment is intended to convert the porous oxide film to γ-alumina, and γ-alumina is better in terms of the efficiency of the hydrogen catalyst reaction. Usually, it is performed at 300 to 550 ° C. for 0.1 to 5 hours.

The metal catalyst described in the present invention is a metal for a hydrogen catalyst, including metals such as nickel, palladium, platinum, rhodium, iridium, rhenium, ruthenium, molybdenum, tungsten, vanadium, osmium, chromium, cobalt, iron, and alloys thereof. Can be used.
The method of supporting the metal catalyst on the porous oxide film is performed by immersing the catalyst metal in a colloidally dispersed liquid or electrolessly plating the metal catalyst.

The hydrogen medium described in the present invention is a medium that releases and stores hydrogen and is not particularly limited as long as it is stable and dehydrogenated to become a stable aromatic. Monocyclic hydrogenated aromatics such as cyclohexane, methylcyclohexane and dimethylcyclohexane, bicyclic hydrogenated aromatics such as tetralin, decalin and methyldecalin, and tricyclic hydrogenated aromatics such as tetradecahydroanthracene More preferred are monocyclic hydrogenated aromatics such as cyclohexane, methylcyclohexane and dimethylcyclohexane, and bicyclic hydrogenated aromatics such as tetralin, decalin and methyldecalin.
Hereinafter, these hydrogen media store hydrogen by adding hydrogen to a double bond between carbon atoms. The hydrogen supply body after hydrogen addition releases hydrogen and returns to the original hydrogen storage body. In the present invention, it is preferable to use a catalyst capable of storing and supplying hydrogen at a lower temperature, and the energy efficiency of the entire system can be improved.

The aluminum foil described in the present invention is a deformable aluminum foil which is processed to be uneven. The thickness of the range of the range which can be wound up in roll shape is used. The aluminum foil is from several μm to several 100 μm, and for example, an industrially produced one of about 20 μm to 1500 μm can be used.
The unevenness processing method can be used without any particular limitation, for example, embossing using a die forming roller with an embossing roll, embossing, mat processing with sandblasting, and the like. The partial processing such as embossing can be performed even after the metal catalyst is supported on the porous oxide film.
The height of the concavo-convex processing is such a size as to obtain the desired air permeability between the foils, and a height of 10 μm or more is used.
When the convex portions are deformations of the foil itself, the intervals between the convex portions are provided so that the convex portions of the stacked layers do not overlap each other.
The method of winding is to match the reaction vessel to be inserted, such as a circular, elliptical, oval cross-section, or a rounded oval shape, or a zigzag folded shape. Do it.

When the surface shape of the foil is provided with a structure of holes (etching pits) roughened in a tunnel shape having a hole diameter of micron order by etching, the reaction surface area is increased. In particular, when the etching pit is lengthened to penetrate the foil, the movement of the hydrogen medium and hydrogen can be improved.
The method of roughening the aluminum foil into the above-mentioned etching pits is, for example, as an aluminum foil, in which cubic iron recrystallized grains formed by partial annealing after cold rolling of aluminum mixed with a small amount of iron, etc. The one that has been subjected to additional rolling and then subjected to final annealing to develop a strong cubic orientation is used.
For example, an aluminum foil that has been conventionally used as an electrode for an aluminum electrolytic capacitor for medium to high voltage can be used. The etching hole diameter is preferably about 1 μm to 5 μm.
In addition, when etching is used for aluminum foil, even when the porous oxide film is thin, the porous film is stored efficiently and does not necessarily need to be thickened. It becomes possible to cope with the facilities.
The diameter of the above-mentioned etching pit employed in aluminum electrolytic capacitors is 2 μm or less, and the thickness of the porous oxide film cannot be increased with existing equipment, but the porous surface is increased due to the increased surface area. The volume storage efficiency of the membrane can be increased. Further, since the thickness of the porous oxide film is not thick, the thermal diffusion efficiency can be increased and the anodizing process can be shortened. In order to increase the growth rate of the oxide film by anodic oxidation, it is sufficient to increase the formation voltage and increase the current density. Therefore, formation with low voltage and low current density is desirable, but in this case, it takes a long time and a large-scale facility is required.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a case where an aluminum foil 3 is embossed and wound as a hydrogen catalyst member. By providing the embossed concavo-convex portion 7 on the aluminum foil 3 by embossing, the aluminum foil 3 is prevented from closely adhering by winding, and the flow of the substance (hydrogen medium and hydrogen) before and after the reaction is smoothed.
When the aluminum foil 3 is wound in a coil shape, it is easy to handle when the container cross-sectional shape is a cylinder. In Patent Document 1, it is a structure in which a small number of thick plates are stacked, whereas in a structure in which a foil is wound, a foil base metal and a porous oxide film on the surface are microscopic structures that are alternately wound, so that heat dispersibility is excellent. Since it is not necessary to increase the thickness of the foil metal, the storage efficiency of the porous oxide film can be increased.
FIG. 2 shows a case where a flat aluminum foil 3 is laminated on a corrugated aluminum foil 3 and wound as a hydrogen catalyst member. The shape of the undulating process may be a undulating curve, a mountain-shaped line, or an intermediate point.
FIG. 3 shows a hydrogen catalyst member having a shape such as a quadrangular pyramid, in which a hole is formed in the aluminum foil 3, and a convex portion 8 of a hole burr (referred to as a burr formed when the hole is formed) is provided in the aluminum foil 3. Shows the case.
In this case, the through-hole is formed simultaneously with the formation of the hole burr protrusion 8. In addition, when the tip of the convex portion 8 of the hole burr is wound and laminated, it is easy to fix the winding if it is pierced or dented to the adjacent foil to some extent.
FIG. 4 shows a schematic view of a hydrogen catalyst member and a hydrogen reaction unit using the hydrogen catalyst member.
FIG. 4A shows a schematic view of a hydrogen catalyst member and a hydrogen reaction unit using the hydrogen catalyst member.
FIG. 4B shows a partially enlarged sectional view of the hydrogen catalyst member.

FIG. 4A shows a hydrogen reaction vessel 1 and a gas-liquid separation vessel 2 connected to the hydrogen reaction unit 1 as a hydrogen reaction unit. The raw material (a hydrogen medium of a hydrogen supply body or a hydrogen and hydrogen storage body, which is a substance before the reaction). It is shown that the hydrogen medium) in the hydrogen reaction vessel 1 undergoes hydrogen reaction and is separated into gas and liquid in the gas-liquid separation vessel 2 connected thereto. Further, it is shown that an aluminum foil 3 provided with a porous oxide film, which is a hydrogen catalyst member, is wound and provided in the hydrogen reaction vessel 1. Further, the hydrogen reaction vessel 1 is heated as necessary.
A plurality of rolls may be provided in the hydrogen reaction vessel 1 by changing a plurality of shapes, configurations, and the like as necessary.
In the dehydrogenation reaction, the hydrogen medium of the hydrogen supplier to which hydrogen as a raw material has been added undergoes a dehydrogenation reaction in the hydrogen reaction vessel 1, and the resulting reaction product is brought to the gas side by the gas-liquid separation vessel 2 connected thereto. Indicates that hydrogen is separated into a hydrogen reservoir on the liquid side.
In the hydrogen addition reaction, hydrogen as a raw material and the hydrogen medium of the hydrogen storage body before the addition of hydrogen undergo a hydrogen addition reaction in the hydrogen reaction vessel 1, and the gas-liquid separation vessel 2 connected to the hydrogen addition reaction causes It shows that unreacted hydrogen is separated, and a hydrogen medium of a hydrogenated hydrogen supply body is produced on the liquid side.

In FIG. 4B, a porous oxide film 5 having pores 4 in a tunnel shape is formed on the surface of the aluminum foil 3, and a metal catalyst 6 that performs dehydrogenation or hydrogenation is formed on the surface of the porous oxide film 5. It shows that it is supported.

  Hereinafter, the method for producing a hydrogen catalyst member of the present invention will be described based on examples.

Example 1
First, an anodized layer having tunnel-shaped pores substantially perpendicular to the surface is continuously formed on an aluminum foil having a thickness of about 150 μm by anodization, and then the pores are enlarged and then boehmite treated.
Next, the treated foil is immersed in a colloidal dispersion of a metal catalyst for dehydrogenation, and the metal catalyst is supported on the porous oxide film.
Next, the embossing which uses the roller of the shaping | molding with an embossing roll is performed continuously. The height of the embossed unevenness is about 200 μm on average.
Next, in accordance with the shape of the hydrogen reaction vessel, the supported foil is wound around a winding shaft to form a coil to obtain a hydrogen catalyst member.

(Example 2)
First, an anodized layer having tunnel-like pores substantially perpendicular to the surface is continuously formed on an aluminum foil having a thickness of about 100 μm by an anodic oxidation method, and then the pores are enlarged and then subjected to boehmite treatment.
Next, the treated foil is immersed in a colloidal dispersion of a metal catalyst for dehydrogenation, and the metal catalyst is supported on the porous oxide film.
Next, the foil is divided into two, and one of them is continuously waved. The height of the corrugations of the wavy processing is about 2 mm on average.
Next, according to the shape of the hydrogen reaction vessel, the supported corrugated processing foil and the other flat foil are overlapped and wound into a coil to obtain a hydrogen catalyst member.

(Example 3)
First, an anodized layer having tunnel-shaped pores substantially perpendicular to the surface is continuously formed on an aluminum foil having a thickness of about 150 μm by anodization, and then the pores are enlarged and then boehmite treated.
Next, the treated foil is immersed in a colloidal dispersion of a metal catalyst for dehydrogenation, and the metal catalyst is supported on the porous oxide film.
Next, hole-burrs are formed by intermittently providing quadrangular pyramidal protrusions on the roll and continuously passing the aluminum foil between the rolls that receive the protrusions. The height of the uneven processing of hole burr processing is about 200 μm on average.
Next, in accordance with the shape of the hydrogen reaction vessel, the supported foil is wound around a winding shaft to form a coil to obtain a hydrogen catalyst member.

DESCRIPTION OF SYMBOLS 1 ... Hydrogen reaction container, 2 ... Gas-liquid separation container, 3 ... Aluminum foil, 4 ... Fine pore, 5 ... Porous oxide film, 6 ... Metal catalyst, 7 ... Embossing uneven | corrugated | grooved part, 8 ... Convex part of a hole burr | flash.

Claims (4)

  Using a catalyst carrier with a metal catalyst supported on a porous oxide film, using a medium that repeatedly stores and supplies hydrogen chemically, a hydrogen catalyst member that performs dehydrogenation to extract hydrogen or hydrogen addition to take in hydrogen, uneven aluminum A hydrogen catalyst member in which a porous oxide film is provided on the surface of a foil and laminated or wound.   The hydrogen catalyst member according to claim 1, wherein the aluminum foil is processed to be uneven by embossing.   The hydrogen catalyst member according to claim 1, wherein the aluminum foil includes a through hole.   The hydrogen catalyst member according to claim 1, 2, or 3, wherein the aluminum foil is provided with a hole whose surface is roughened in a tunnel shape from the surface by etching.

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