JP2017081774A - Dehydrogenation catalyst, manufacturing method of dehydrogenation catalyst, dehydrogenation reactor, manufacturing method of dehydrogenation reactor, manufacturing system of hydrogen and manufacturing method of hydrogen - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dehydrogenation reactor capable of suppressing demethylation associated with dehydrogenation of cyclic saturated hydrocarbon having a methyl group.SOLUTION: A dehydrogenation reactor has a reaction room, AlOcarrying Pt arranged in the reaction room and TiOarranged in the reaction room and is used for dehydrogenation of cyclic saturated hydrocarbon having a methyl group.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a dehydrogenation catalyst, a dehydrogenation catalyst production method, a dehydrogenation reactor, a dehydrogenation reactor production method, a hydrogen production system, and a hydrogen production method.

  In recent years, it is expected that a fuel cell using hydrogen with a small environmental load as a fuel will be used as a power source of an automobile or the like. In the process of transporting, storing and supplying hydrogen, for example, naphthenic hydrocarbons (cyclic hydrocarbons) are used. For example, in a hydrogen production facility, naphthenic hydrocarbons are generated by hydrogenation of aromatic hydrocarbons. This naphthenic hydrocarbon is transported to a hydrogen consumption area or stored in the consumption area. In the consumption area, hydrogen and aromatic hydrocarbons are generated by dehydrogenation of naphthenic hydrocarbons. This hydrogen is supplied to the fuel cell. Naphthenic hydrocarbons are liquid at room temperature, have a smaller volume than hydrogen gas, are less reactive than hydrogen gas, and are safe. Therefore, naphthenic hydrocarbons are more suitable for transportation and storage than hydrogen gas.

  As a dehydrogenation catalyst for naphthenic hydrocarbons, a catalyst in which a platinum-rhenium bimetal is supported on an alumina carrier is known (see Non-Patent Document 1 below).

R. W. Coughlin, K.M. Kawakami, Akram Hasan, Journal of Catalysis, Vol. 88, 150-162 (1984).

  The present invention relates to a dehydrogenation catalyst capable of suppressing demethylation accompanying dehydrogenation of a cyclic saturated hydrocarbon having a methyl group, a method for producing the dehydrogenation catalyst, a dehydrogenation reactor, and production of the dehydrogenation reactor. It is an object to provide a method, a hydrogen production system using the dehydrogenation reactor, and a hydrogen production method.

A dehydrogenation reactor according to one aspect of the present invention includes a reaction chamber, Al ₂ O ₃ loaded with Pt, disposed in the reaction chamber, and TiO ₂ disposed in the reaction chamber. , Used for dehydrogenation of cyclic saturated hydrocarbons having a methyl group.

The dehydrogenation reactor according to one aspect of the present invention may include a reaction chamber, and a first catalyst unit and a second catalyst unit disposed in the reaction chamber, and the first catalyst unit carries Pt. Al ₂ O ₃ may be included, and the second catalyst portion may include TiO ₂ .

  In the dehydrogenation reactor according to one aspect of the present invention, a cyclic saturated hydrocarbon supply port may be formed in the reaction chamber, and a discharge port for a product generated in the reaction chamber may be formed in the reaction chamber. The second catalyst unit may be located between the supply port and the discharge port, and the first catalyst unit may be located between the second catalyst unit and the discharge port.

The dehydrogenation reactor according to one aspect of the present invention may include a reaction chamber, and first particles and second particles disposed in the reaction chamber, and the first particles are Al on which Pt is supported. ₂ O ₃ may be included, the second particles may include TiO ₂ , and the first particles and the second particles may be mixed in the reaction chamber.

The dehydrogenation reactor according to one aspect of the present invention may include a reaction chamber and third particles disposed in the reaction chamber, and the third particles include Al ₂ O ₃ supporting Pt and , TiO ₂ .

In the dehydrogenation reactor according to one aspect of the present invention, the crystallite diameter of TiO ₂ may be 35 nm or less.

A method for producing a dehydrogenation reactor according to one aspect of the present invention is a method for producing the dehydrogenation reactor, wherein the first raw material containing Pt-supported Al ₂ O ₃ is sized, A step of obtaining one particle, a step of sizing a second raw material containing TiO ₂ to obtain a second particle, and a step of mixing the first particle and the second particle.

A method for producing a dehydrogenation reactor according to one aspect of the present invention is a method for producing the dehydrogenation reactor, wherein the first raw material contains Al ₂ O ₃ on which Pt is supported, and the first raw material contains TiO ₂ . Two raw materials are mixed to obtain a third raw material containing the first raw material and the second raw material, and a step of sizing the third raw material to obtain third particles.

In the method for producing a dehydrogenation reactor according to one aspect of the present invention, the crystallite diameter of TiO ₂ may be 35 nm or less.

A dehydrogenation catalyst according to an aspect of the present invention includes Al ₂ O ₃ supporting Pt and TiO ₂ and is used for dehydrogenation of a cyclic saturated hydrocarbon having a methyl group.

The dehydrogenation catalyst according to one aspect of the present invention may include first particles and second particles, and the first particles may include Al ₂ O ₃ supporting Pt, and the second particles but it may include TiO _2, may have mixed first particles and the second particles.

The dehydrogenation catalyst according to one aspect of the present invention may include third particles, and the third particles may include Al ₂ O ₃ supporting Pt and TiO ₂ .

In the dehydrogenation catalyst according to one aspect of the present invention, the crystallite diameter of TiO ₂ may be 35 nm or less.

A method for producing a dehydrogenation catalyst according to an aspect of the present invention is a method for producing the above dehydrogenation catalyst, wherein the first raw material containing Pt-supported Al ₂ O ₃ is sized, and the first particles A step of adjusting the second raw material containing TiO ₂ to obtain second particles, and a step of mixing the first particles and the second particles.

A method for producing a dehydrogenation catalyst according to an aspect of the present invention is a method for producing the above dehydrogenation catalyst, which includes a first raw material containing Al ₂ O ₃ on which Pt is supported, and a second raw material containing TiO _2. And a step of obtaining a third raw material containing the first raw material and the second raw material and a step of adjusting the third raw material to obtain third particles.

In the method for producing a dehydrogenation catalyst according to one aspect of the present invention, the crystallite diameter of TiO ₂ may be 35 nm or less.

  A hydrogen production system according to one aspect of the present invention includes the dehydrogenation reactor.

  The method for producing hydrogen according to one aspect of the present invention includes a step of generating hydrogen by dehydrogenation of a cyclic saturated hydrocarbon in the dehydrogenation reactor.

  ADVANTAGE OF THE INVENTION According to this invention, the dehydrogenation catalyst which can suppress the demethylation accompanying dehydrogenation of the cyclic saturated hydrocarbon which has a methyl group, the manufacturing method of the said dehydrogenation catalyst, a dehydrogenation reactor, the said dehydrogenation reactor , A hydrogen production system using the dehydrogenation reactor, and a hydrogen production method can be provided.

(A) in FIG. 1 is a schematic view showing a dehydrogenation reactor according to the first embodiment of the present invention. (B) in FIG. 1 is a schematic diagram showing a dehydrogenation reactor according to a second embodiment of the present invention. (A) in FIG. 2 is a schematic diagram showing an example of a dehydrogenation reactor according to the third embodiment of the present invention. (B) in FIG. 2 is a schematic view showing another example of the dehydrogenation reactor according to the third embodiment of the present invention. FIG. 3 is a schematic view showing an embodiment of the hydrogen production system according to the present invention. FIG. 4 is a diagram showing an X-ray diffraction (XRD) pattern of TiO ₂ after firing. FIG. 5 is a diagram showing the relationship between the dehydrogenation reaction time and the methane production rate in Examples 1 to 4 and Comparative Example 1. FIG. 6 is a diagram showing the relationship between the dehydrogenation reaction time in Examples 1 to 4 and Comparative Example 1 and the methane concentration (ppm) in the produced hydrogen. FIG. 7 is a diagram showing the relationship between the dehydrogenation reaction time and the hydrogen yield in Examples 1 to 4 and Comparative Example 1. FIG. 8 is a graph showing the relationship between the dehydrogenation reaction time and the methane production rate in Examples 1, 5 and 6. FIG. 9 is a graph showing the relationship between the dehydrogenation reaction time in Examples 1, 5 and 6, and the methane concentration (ppm) in the produced hydrogen. FIG. 10 is a graph showing the relationship between the dehydrogenation reaction time and the hydrogen yield in Examples 1, 5 and 6. FIG. 11 is a diagram showing the relationship between the dehydrogenation reaction time and the methane production rate in Examples 7 to 9 and Comparative Example 2. FIG. 12 is a diagram showing the relationship between the dehydrogenation reaction time in Examples 7 to 9 and Comparative Example 2 and the methane concentration (ppm) in the produced hydrogen. FIG. 13 is a graph showing the relationship between the dehydrogenation reaction time and the hydrogen yield in Examples 7 to 9 and Comparative Example 2. FIG. 14 is a graph showing the relationship between the dehydrogenation reaction time and the methane production rate in Examples 10 and 11. FIG. 15 is a graph showing the relationship between the dehydrogenation reaction time in Examples 10 and 11 and the methane concentration (ppm) in the produced hydrogen. FIG. 16 is a graph showing the relationship between the dehydrogenation reaction time and the hydrogen yield in Examples 10 and 11.

  Hereinafter, preferred embodiments of the present invention will be described. However, the present invention is not limited to the following embodiment. In the drawings, the same components are denoted by the same reference numerals.

A dehydrogenation catalyst according to one aspect of the present invention includes Al ₂ O ₃ on which Pt is supported and TiO ₂ . A dehydrogenation reactor according to one aspect of the present invention includes a reaction chamber and the dehydrogenation catalyst disposed in the reaction chamber. The dehydrogenation reactor according to one aspect of the present invention is used for dehydrogenation of a cyclic saturated hydrocarbon having a methyl group. Hereinafter, “Al ₂ O ₃ supporting Pt” is also referred to as “Pt / Al ₂ O ₃ ”.

  The dehydrogenation reactor according to one aspect of the present invention can suppress demethylation associated with dehydrogenation of a cyclic saturated hydrocarbon having a methyl group, as compared with a conventional dehydrogenation reactor. “Demethylation” is elimination of a methyl group from a cyclic saturated hydrocarbon and formation of methane. That is, according to the present invention, generation of methane accompanying dehydrogenation of a cyclic saturated hydrocarbon having a methyl group can be suppressed.

  The cyclic saturated hydrocarbon having a methyl group may be at least one selected from the group consisting of methylcyclohexane, dimethylcyclohexane, 1-methyldecalin, and 2-methyldecalin, for example. These compounds are called organic hydrides. The cyclic saturated hydrocarbon having a methyl group is preferably at least one selected from the group consisting of methylcyclohexane and dimethylcyclohexane.

  For example, in the dehydrogenation reaction of methylcyclohexane using a conventional dehydrogenation catalyst, not only toluene is generated by dehydrogenation, but also a carbon-carbon bond breaking reaction proceeds, so that a methyl group is desorbed from toluene, and a secondary group is removed. The products benzene and methane are produced.

The present invention is divided into a first embodiment, a second embodiment, and a third embodiment. In the first embodiment and the second embodiment, Pt / Al ₂ O ₃ and TiO ₂ are physically mixed. In the third embodiment, the dehydrogenation catalyst is divided into a first catalyst part containing Pt / Al ₂ O ₃ and a second catalyst part containing TiO ₂ . Hereinafter, the first embodiment and the second embodiment will be described first, and then the third embodiment will be described.

(First embodiment)
As shown in FIG. 1A, the dehydrogenation reactor 2 a according to the first embodiment includes a reaction chamber 4 and a dehydrogenation catalyst 6 disposed in the reaction chamber 4. The dehydrogenation catalyst 6 includes first particles 8a and second particles 8b. “Particle” refers to a plurality of particles. The first particles 8a contain Pt / Al ₂ O ₃ . Second particle 8b comprises TiO _2. First particle 8a can consist only Pt / _Al 2 _{O 3.} Second particle 8b may consist only TiO _2. In the dehydrogenation catalyst 6, the first particles 8a and the second particles 8b are mixed. In the reaction chamber 4, a filler may be disposed in a region where the dehydrogenation catalyst 6 does not exist. The dehydrogenation catalyst 6 may be fixed at a predetermined position in the reaction chamber 4 by arranging a filler. The filler may be an inert substance that does not contribute to the dehydrogenation reaction.

  In the method for producing hydrogen according to the first embodiment, the cyclic saturated hydrocarbon 10 having a methyl group is supplied into the dehydrogenation reactor 2a, and the cyclic saturated hydrocarbon 10 is brought into contact with the dehydrogenation catalyst 6. As a result, the dehydrogenation reaction of the cyclic saturated hydrocarbon 10 occurs in the dehydrogenation reactor 2a, and the product 12 is obtained. The product 12 includes an unsaturated hydrocarbon having a methyl group and hydrogen.

According to the first embodiment, demethylation associated with dehydrogenation can be suppressed as compared with the case where the dehydrogenation catalyst is composed only of Pt / Al ₂ O ₃ .

In the method for manufacturing the dehydrogenation reactor 2a according to the first embodiment, the first raw material containing Pt / Al ₂ O ₃ is sized to obtain the first particles 8a, and the second raw material containing TiO ₂ is used. The step of sizing to obtain the second particles 8b, the step of mixing the first particles 8a and the second particles 8b to produce the dehydrogenation catalyst 6, and the step of installing the dehydrogenation catalyst 6 in the reaction chamber 4 And comprising. In the production method according to the dehydrogenation catalyst 6 according to the first embodiment, the first raw material containing Pt / Al ₂ O ₃ is sized to obtain the first particles 8a, and the second raw material containing TiO ₂ is used. The method includes adjusting the size to obtain the second particles 8b and mixing the first particles 8a and the second particles 8b.

The first raw material is produced, for example, by a method including a pulverizing step of further pulverizing a powdery carrier containing Al ₂ O ₃ and a supporting step of supporting Pt on the pulverized carrier. The grinding method used in the grinding process may be a planetary ball mill, for example. In the Pt loading process, for example, a support containing Al ₂ O ₃ may be impregnated with a Pt solution (for example, an aqueous solution). Further, the carrier impregnated with the Pt solution may be dried or further baked.

Al ₂ O ₃ contained in the support may be, for example, α-alumina, δ-alumina, θ-alumina, γ-alumina, or alumite. The support may consist only of Al ₂ O ₃ . The specific surface area of Al ₂ O ₃ is not particularly limited, for example, may be 100 to 500 m ² / g.

  Examples of the method of supporting Pt on a carrier include an incipient wetness method, an impregnation method (pore filling method), an adsorption method, an immersion method, an evaporation to dryness method, a spray method, an ion exchange method, or a liquid phase reduction method. Good. By these methods, Pt is attached to the surface of the carrier. The amount of Pt supported in the first raw material can be adjusted by the concentration of Pt in the Pt solution or the amount of the Pt solution used.

  A solution of Pt can be prepared, for example, by dissolving a Pt compound in a solvent. The Pt compound is not particularly limited, but is required to be soluble in a liquid solvent. The Pt compound may be nitrate, sulfate, carbonate, acetate, phosphate, oxalate, borate, chloride, alkoxide, acetylacetonate, and the like.

  Pt compounds are tetrachloroplatinic acid, potassium tetrachloroplatinate, ammonium tetrachloroplatinate, sodium tetrachloroplatinate, bis (acetylacetonato) platinum, diamminedichloroplatinum, dinitrodiammineplatinum, tetraammineplatinum dichloride, tetraammineplatinum water Acid salt, tetraammine platinum nitrate, tetraammine platinum acetate, tetraammine platinum carbonate, tetraammine platinum phosphate, hexaammine platinum tetrachloride, hexaammine platinum hydrochloride, hexaammine platinum hydrochloride, bis (ethanolammonium) hexahydroxo At least one selected from the group consisting of platinum (IV), sodium hexahydroxoplatinum (IV), potassium hexahydroxoplatinum (IV), platinum nitrate and platinum sulfate, There.

  Pt is supported on the carrier by firing the carrier carrying the Pt compound and decomposing the Pt compound. The firing temperature may be a temperature at which decomposition of the Pt compound proceeds, and may be, for example, about 473 to 773K.

As described above, the carrier containing Al ₂ O ₃ is pulverized, and Pt is supported on the pulverized carrier, whereby the first raw material is completed. The particle diameter of the first raw material may be about 5 to 50 μm, for example.

  The first particles 8a are obtained by regulating the size of the first raw material. “Sizing” means processing a raw material (first raw material) into predetermined particles (first particles 8a). For example, the sizing includes a step of compression-molding a raw material to obtain a molded body, and a step of pulverizing the molded body to obtain predetermined particles. The sizing may further include a step of classifying particles (pulverized product) to obtain particles having a predetermined particle size. The means for compression molding the raw material (first raw material) may be, for example, a tableting machine. The means for pulverizing the molded body may be, for example, a means for pulverizing using a pestle in an agate mortar. The means for classifying the particles (the pulverized product) may be, for example, a mesh.

  The particle diameter of the first particles 8a immediately after sizing may be, for example, about 250 to 500 μm. “Immediately after sizing” means after sizing and before mixing. When the particle diameter of the first particles 8a is within the above range, the influence of the diffusion of the reactant on the dehydrogenation reaction is likely to be reduced. Moreover, when the particle diameter of the 1st particle | grains 8a is in the said range, the pressure loss in a dehydrogenation reactor is easy to be reduced.

The second raw material is manufactured, for example, by a method comprising a pulverizing step of pulverizing the TiO ₂ as the starting material, a firing step of firing the TiO ₂ milled, the. The grinding method used in the grinding process may be a planetary ball mill, for example.

The crystal structure of TiO ₂ as a starting material may be anatase type, rutile type, or brookite type. Among the above-mentioned plural types of TiO ₂ , anatase TiO ₂ is relatively preferable. The crystal structure of TiO ₂ contained in the completed dehydrogenation catalyst 6 may be anatase type, rutile type, or brookite type. When the dehydrogenation catalyst 6 contains anatase-type TiO ₂ , demethylation associated with dehydrogenation is more easily suppressed as compared with the case where other types of TiO ₂ are used.

The firing temperature of TiO ₂ may be, for example, 573 to 1073K, or 673 to 973K.

As described above, by grinding TiO _2, by firing TiO ₂ milled, second raw material is completed. The particle diameter of the second raw material may be about 5 to 50 μm, for example.

The smaller the crystallite size of TiO _2, the more easily the demethylation accompanying dehydrogenation is suppressed. The “crystallite diameter” is an average value of the crystallite size calculated from the measurement result of the X-ray diffraction method (XRD method) according to the following Scherrer equation (1).
D _hkl = (K · λ) / (βcos θ) (1)

In formula (1), D _hkl is the “crystallite diameter” in the direction perpendicular to the (hkl) plane of the crystallite, K is the Scherrer constant, and λ is the wavelength of X-rays used in the XRD method. , Β is the spread (half-value width or integral width) of the diffraction X-ray peak on the (hkl) plane, and θ is the Bragg angle of the diffraction X-ray. In the case of a crystallite diameter of TiO ₂ , θ may be 12.64 °, for example. Crystallite size of TiO ₂ may be a crystallite size _{D 101} in the direction perpendicular to the (101) plane of anatase TiO _2.

The crystallite diameter of TiO ₂ may be, for example, 10 to 55 nm, or 14 to 35 nm. When the crystallite diameter of TiO ₂ is within the above range, demethylation accompanying dehydrogenation is more easily suppressed.

The specific surface area of TiO _2, for example 10 to 150 m ² / g, or 30~120m may be ² / g or less. The specific surface area may be measured by, for example, the BET method. When the specific surface area of TiO ₂ is within the above range, demethylation accompanying dehydrogenation is more easily suppressed.

  The second particles 8b are obtained by regulating the size of the second raw material. The method of sizing the second raw material may be the same as the method of sizing the first raw material.

  The particle diameter of the second particles 8b immediately after sizing may be, for example, about 250 to 500 μm. When the particle diameter of the second particles 8b is within the above range, the influence of the diffusion of the reactant on the dehydrogenation reaction is likely to be reduced. Moreover, when the particle diameter of the 2nd particle | grains 8b is in the said range, the pressure loss in a dehydrogenation reactor is easy to be reduced.

  The dehydrogenation catalyst 6 is obtained by mixing the first particles 8a and the second particles 8b obtained by the above method. By placing the dehydrogenation catalyst 6 in the reaction chamber 4, the dehydrogenation reactor 2a is completed. The means for mixing the first particles 8a and the second particles 8b may be, for example, mixing in a beaker.

  The particle diameter of the first particle 8a after mixing the first particle 8a and the second particle 8b may not change from the particle diameter of the first particle 8a before mixing.

  The particle diameter of the second particle 8b after mixing the first particle 8a and the second particle 8b may not change from the particle diameter of the second particle 8b before mixing.

When the content of Pt / Al ₂ O ₃ contained in the dehydrogenation catalyst 6 is 100 parts by mass, the content of TiO ₂ contained in the dehydrogenation catalyst 6 is, for example, 25 to 400 parts by mass, or 50 to 200 parts by mass. Part. The lower the TiO ₂ content, the easier it is to improve the yield of hydrogen at the initial stage of the dehydrogenation reaction. The greater the content of TiO _2, the easier the demethylation associated with the dehydrogenation reaction is suppressed.

Note that a dehydrogenation catalyst obtained by mixing particles obtained by sizing TiO ₂ (Pt / TiO ₂ ) on which Pt is supported and particles obtained by sizing TiO ₂ is used. In such a case, the yield of hydrogen is smaller than when a dehydrogenation catalyst composed of particles obtained by regulating only Pt / TiO ₂ is used.

(Second Embodiment)
As shown in FIG. 1B, the dehydrogenation reactor 2 b according to the second embodiment includes a reaction chamber 4 and a dehydrogenation catalyst 14 disposed in the reaction chamber 4. The dehydrogenation catalyst 14 includes third particles 14a. The third particles 14a include Pt / Al ₂ O ₃ and TiO ₂ . The third particle 14a includes a Pt / _Al 2 _{O 3,} may consist as TiO ₂ only. In the reaction chamber 4, a filler may be disposed in a region where the dehydrogenation catalyst 14 does not exist. The dehydrogenation catalyst 14 may be fixed at a predetermined position in the reaction chamber 4 by arranging a filler. The filler may be an inert substance that does not contribute to the dehydrogenation reaction.

  In the method for producing hydrogen according to the second embodiment, the cyclic saturated hydrocarbon 10 having a methyl group is supplied into the dehydrogenation reactor 2b, and the cyclic saturated hydrocarbon 10 is brought into contact with the dehydrogenation catalyst 14. As a result, the dehydrogenation reaction of the cyclic saturated hydrocarbon 10 occurs in the dehydrogenation reactor 2b, and the product 12 is obtained. The product 12 includes an unsaturated hydrocarbon having a methyl group and hydrogen.

According to the second embodiment, demethylation associated with dehydrogenation can be suppressed as compared with the case where the dehydrogenation catalyst is composed only of Pt / Al ₂ O ₃ .

The method for producing the dehydrogenation reactor 2b according to the second embodiment includes the first raw material and the second raw material by mixing the first raw material containing Pt / Al ₂ O ₃ and the second raw material containing TiO _2. A step of obtaining a third raw material, a step of adjusting the third raw material to obtain third particles 14a, a step of producing a dehydrogenation catalyst 14 including the third particles 14a, and a dehydrogenation catalyst 14 in the reaction chamber 4 And a process of installing in. In other words, in the method for producing the dehydrogenation catalyst 14 according to the second embodiment, the first raw material and the second raw material are mixed by mixing the first raw material containing Pt / Al ₂ O ₃ and the second raw material containing TiO _2. And a step of obtaining a third particle 14a by sizing the third raw material. The dehydrogenation catalyst 14 according to the second embodiment may consist only of the third particles 14a.

  The first raw material may be the same as the first raw material in the first embodiment. The second raw material may be the same as the second raw material in the first embodiment. The means for mixing the first raw material and the second raw material may be, for example, a planetary ball mill. The particle diameter of the third raw material may be about 5 to 50 μm, for example.

  As described above, the third particles 14a are obtained by sizing the third raw material. The method of “sizing” to obtain the third particles 14a may be the same as the method of sizing in the first embodiment. The particle diameter of the third particles 14a immediately after sizing may be, for example, about 250 to 500 μm. When the particle diameter of the third particles 14a is within the above range, the influence of the diffusion of the reactant on the dehydrogenation reaction is likely to be reduced. Moreover, when the particle diameter of the 3rd particle | grains 14a is in the said range, the pressure loss in a dehydrogenation reactor is easy to be reduced.

When the content of Pt / Al ₂ O ₃ contained in the dehydrogenation catalyst 14 is 100 parts by mass, the content of TiO ₂ contained in the dehydrogenation catalyst 14 is, for example, 25 to 400 parts by mass, or 50 to 200 parts by mass. Part. The greater the content of TiO _2, the easier the demethylation associated with the dehydrogenation reaction is suppressed.

When the crystallite diameter of TiO ₂ is 35 nm or less, the first embodiment is more effective in suppressing demethylation associated with dehydrogenation than the second embodiment. The second embodiment is more excellent in the yield of hydrogen in the initial stage of the dehydrogenation reaction than the first embodiment.

In the first embodiment, the first raw material containing Pt / Al ₂ O ₃ and the second raw material containing TiO ₂ are each sized and mixed. In the second embodiment, the first raw material containing Pt / Al ₂ O ₃ and the second raw material containing TiO ₂ were mixed and then sized. The present inventors consider that the order of such sizing and mixing is one of the factors that determine the distance between Pt and TiO ₂ in the dehydrogenation catalyst. The distance between Pt and TiO ₂ in the dehydrogenation catalyst according to the first embodiment tends to be larger than the distance between Pt and TiO ₂ in the dehydrogenation catalyst according to the second embodiment. Further, the present inventors consider that the order of the sizing and mixing as described above is one of the factors that determine the area of the contact interface between Pt / Al ₂ O ₃ and TiO ₂ in the dehydrogenation catalyst. Think. The area of the contact interface between Pt / Al ₂ O ₃ and TiO ₂ in the dehydrogenation catalyst according to the first embodiment is equal to the contact interface between Pt / Al ₂ O ₃ and TiO ₂ in the dehydrogenation catalyst according to the second embodiment. It tends to be smaller than the area.

(Third embodiment)
As shown to (a) in FIG. 2, the dehydrogenation reactor 20a which concerns on 3rd Embodiment is provided with the reaction chamber 4 and the dehydrogenation catalyst 22 arrange | positioned in the reaction chamber 4. FIG. The dehydrogenation catalyst 22 includes a first catalyst part 24 (first catalyst layer) and a second catalyst part 26 (second catalyst layer). The first catalyst unit 24 includes Pt / Al ₂ O ₃ . The second catalyst unit 26 includes TiO ₂ . The first catalyst portion 24 may consist only Pt / _Al 2 _{O 3.} The second catalyst unit 26 can consist of only TiO _2. In the reaction chamber 4, a filler may be disposed in a region where the dehydrogenation catalyst 22 does not exist. The dehydrogenation catalyst 22 may be fixed at a predetermined position in the reaction chamber 4 by arranging a filler. The filler may be an inert substance that does not contribute to the dehydrogenation reaction. The filler may be disposed in a region between the first catalyst part 24 and the second catalyst part 26. The first catalyst part 24 and the second catalyst part 26 may be completely separated by arranging the filler.

In the dehydrogenation reactor 20a according to the third embodiment, the supply port 28 for the cyclic saturated hydrocarbon 10 is formed in the reaction chamber 4, and the discharge port 30 for the product 12 produced in the reaction chamber 4 is provided in the reaction chamber. Is formed. The second catalyst unit 26 is located between the supply port 28 and the discharge port 30. The first catalyst part 24 is located between the second catalyst part 26 and the discharge port 30. That is, the second catalyst unit 26 including TiO ₂ is positioned upstream of the first catalyst unit 24 including the Pt / _Al 2 _{O 3,} the first catalyst unit 24 including the Pt / _Al 2 _{O 3} is, TiO ₂ is located on the downstream side of the second catalyst part 26 including 2.

  In the method for producing hydrogen according to the third embodiment, the cyclic saturated hydrocarbon 10 having a methyl group is supplied into the dehydrogenation reactor 20a, and the cyclic saturated hydrocarbon 10 first comes into contact with the second catalyst unit 26, and then In contact with the first catalyst unit 24. As a result, the dehydrogenation reaction of the cyclic saturated hydrocarbon 10 occurs in the dehydrogenation reactor 20a, and the product 12 is obtained. The product 12 includes an unsaturated hydrocarbon having a methyl group and hydrogen.

According to the third embodiment, demethylation associated with dehydrogenation can be suppressed as compared with the case where the dehydrogenation catalyst is composed only of Pt / Al ₂ O ₃ .

Al ₂ O ₃ contained in the first catalyst unit 24 may be, for example, α-alumina, δ-alumina, θ-alumina, γ-alumina, or alumite. The method for supporting Pt on Al ₂ O ₃ may be the same as in the first embodiment.

The crystal structure of TiO ₂ contained in the second catalyst portion 26 may be an anatase type, a rutile type, or a brookite type.

When the content of Pt / _Al 2 _{O 3} contained in the first catalyst unit 24 is 100 parts by mass, the content of TiO ₂ contained in the second catalyst unit 26, for example 25 to 400 parts by mass, or 50 to It may be 200 parts by mass. The greater the content of TiO _2, the easier the demethylation associated with the dehydrogenation reaction is suppressed.

In the modification of the third embodiment, for example, as shown in FIG. 2B, the first catalyst unit 24 is positioned between the supply port 28 and the discharge port 30 in the dehydrogenation reactor 20 b. Alternatively, the second catalyst part 26 may be located between the first catalyst part 24 and the discharge port 30. That is, the first catalyst unit 24 including the Pt / _Al 2 _{O 3} may be located upstream of the second catalyst unit 26 including TiO _2, the second catalyst unit 26 comprising TiO _2, the Pt / Al than the first catalyst unit 24 including ₂ O ₃ may be located downstream.

  When the second catalyst part 26 is located on the supply port 28 side and the first catalyst part 24 is located on the discharge port 30 side, the first catalyst part 24 is located on the supply port 28 side, and the second catalyst part Compared with the case where 26 is located on the discharge port 30 side, the effect of suppressing demethylation accompanying dehydrogenation is more excellent. When the first catalyst part 24 is located on the supply port 28 side and the second catalyst part 26 is located on the discharge port 30 side, the second catalyst part 26 is located on the supply port 28 side, and the first catalyst part Compared with the case where 24 is located on the outlet 30 side, the yield of hydrogen in the initial stage of the dehydrogenation reaction is more excellent.

(Hydrogen production system and hydrogen production method)
In one embodiment of the present invention, hydrogen is produced using the hydrogen production system 100 shown in FIG. The hydrogen production system 100 is, for example, a hydrogen station for supplying hydrogen gas as fuel to a fuel cell vehicle.

  The hydrogen production system 100 includes at least a dehydrogenation reactor, a gas-liquid separator 44, a hydrogen purification device 46, and a tank 56. The manufacturing system 100 may further include a high-pressure compressor 54. The dehydrogenation reactor provided in the production system 100 may be a dehydrogenation reactor 2a shown in (a) of FIG. The dehydrogenation reactor provided in the production system 100 may be a dehydrogenation reactor 2b shown in (b) of FIG. The dehydrogenation reactor provided in the production system 100 may be a dehydrogenation reactor 20a shown in (a) of FIG. The dehydrogenation reactor provided in the production system 100 may be a dehydrogenation reactor 20b shown in (b) of FIG. The dehydrogenation reactor has the dehydrogenation catalyst according to the above embodiment. Hydrogen and an organic compound are produced by dehydrogenating a cyclic saturated hydrocarbon having a methyl group using the dehydrogenation catalyst. The organic compound includes an unsaturated hydrocarbon having a methyl group. That is, in the method for producing hydrogen according to the above embodiment, the hydrogen and the unsaturated hydrocarbon having a methyl group are obtained by dehydrogenating the cyclic saturated hydrocarbon having a methyl group in the dehydrogenation reactor according to the above embodiment. The process of producing | generating (dehydrogenation process) is provided.

According to the hydrogen production system according to the above embodiment, demethylation associated with dehydrogenation can be suppressed as compared with the case where the dehydrogenation catalyst is made of only Pt / Al ₂ O ₃ .

  In the dehydrogenation step, a cyclic saturated hydrocarbon having a methyl group is supplied into the dehydrogenation reactor. The dehydrogenation catalyst according to the above embodiment is installed in the dehydrogenation reactor. The inside of the dehydrogenation reactor is a reducing atmosphere. In the dehydrogenation reactor, when the cyclic saturated hydrocarbon having a methyl group comes into contact with the dehydrogenation catalyst, a dehydrogenation reaction takes place, and at least a pair of hydrogen atoms are extracted from the cyclic saturated hydrocarbon. As a result, hydrogen molecules and unsaturated hydrocarbons having a methyl group are generated. Thus, the dehydrogenation reaction is a gas phase reaction. In the dehydrogenation step, hydrogen may be supplied into the dehydrogenation reactor together with the cyclic saturated hydrocarbon having a methyl group. This tends to maintain the dehydrogenation activity for a longer period. Hereinafter, the unsaturated hydrocarbon having a methyl group is simply referred to as “unsaturated hydrocarbon”.

The conditions for the dehydrogenation reaction are not particularly limited. The reaction temperature may be 250 to 420 ° C. (523 to 693 K), or 300 to 400 ° C. (573 to 673 K). In order to adjust the reaction temperature to the above range, the temperature at the center of the catalyst layer in the dehydrogenation reactor may be adjusted to the above range. The liquid hourly space velocity (LHSV) may be 0.2 to 4.0 h ⁻¹ . The reaction pressure may be 0.1 to 1.0 MPa. In the case of supplying hydrogen with cyclic saturated hydrocarbon having a methyl group into the dehydrogenation reactor, the mole number n _H of hydrogen supplied to the dehydrogenation reactor, a methyl group is supplied to the dehydrogenation reactor The ratio n _H / n _C to the number of moles n _C of the cyclic saturated hydrocarbon having may be 0.05 to 1.0.

  The product (hydrogen molecule and unsaturated hydrocarbon) of the dehydrogenation reaction is supplied from the dehydrogenation reactor into the gas-liquid separator 44. The temperature in the gas-liquid separator 44 is not lower than the melting point of the unsaturated hydrocarbon and lower than the boiling point of the unsaturated hydrocarbon. Therefore, the hydrogen molecules in the gas-liquid separator 44 are gases, and the unsaturated hydrocarbons in the gas-liquid separator 44 are liquids. That is, in the gas-liquid separator 44, the product of the dehydrogenation reaction is separated into hydrogen gas (gas phase, gas layer) and unsaturated hydrocarbon liquid (liquid phase, liquid layer). The gas phase (hydrogen-containing gas) in the gas-liquid separator 44 is supplied to the hydrogen purifier 46. The liquid phase (unsaturated hydrocarbon liquid) in the gas-liquid separator 44 is supplied to the tank 56. Note that unsaturated hydrocarbon vapor may be mixed in the gas phase. The partial pressure of unsaturated hydrocarbons in the gas phase is at most about the saturated vapor pressure of unsaturated hydrocarbons. In the method for producing hydrogen according to the above embodiment, since the dehydrogenation reactor according to the above embodiment is used, demethylation accompanying dehydrogenation can be suppressed. On the other hand, organic hydride that has not been dehydrogenated may remain in the liquid phase.

  The hydrogen-containing gas supplied from the gas-liquid separator 44 to the hydrogen purification device 46 is purified by the hydrogen purification device 46. The hydrogen purifier 46 may include, for example, a separation membrane that selectively allows only hydrogen gas among hydrogen gas and unsaturated hydrocarbons to permeate. The separation membrane is, for example, a metal membrane (such as a PbAg-based membrane, a PdCu-based membrane, or an Nb-based membrane), an inorganic membrane (such as a silica membrane, a zeolite membrane, or a carbon membrane), or a polymer membrane (a fluororesin membrane or polyimide). A membrane). The hydrogen gas permeates through the separation membrane, thereby increasing the purity of the hydrogen gas. On the other hand, unsaturated hydrocarbons (such as unreacted organic hydride) in the hydrogen-containing gas cannot permeate the separation membrane. Therefore, unsaturated hydrocarbons are separated from the hydrogen-containing gas, and high-purity hydrogen gas is purified. The purified high-purity hydrogen gas may be used as fuel for the fuel cell without passing through the high-pressure compressor 54, or may be used as fuel for the fuel cell after being compressed by the high-pressure compressor 54. Note that not only unsaturated hydrocarbons but also trace amounts of hydrogen gas may not pass through the carbon film. The hydrogen gas that has not permeated the carbon membrane may be recovered together with the organic hydride and supplied as an off-gas into the dehydrogenation reactor. Alternatively, unsaturated hydrocarbons that have not permeated the carbon membrane may be recovered into the tank 56. The hydrogen purification apparatus 46 is not limited to an apparatus provided with a separation membrane. The hydrogen purifier 46 is selected from the group consisting of, for example, a pressure swing adsorption (PSA) method, a thermal swing adsorption (TSA) method (temperature swing adsorption method), a temperature pressure swing adsorption (TPSA) method, and a cryogenic separation method. An apparatus that performs at least one method may be used. Using these apparatuses, the hydrogen-containing gas may be purified, the off-gas generated along with the purification may be supplied into the dehydrogenation reactor, and the unsaturated hydrocarbon separated from the hydrogen-containing gas may be supplied to the tank 56. . A portion of the purified hydrogen gas may be supplied to the dehydrogenation reactor along with the organic hydride. Thereby, the dehydrogenation activity of the dehydrogenation catalyst in the dehydrogenation reactor is easily maintained.

As mentioned above, although the aspect of this invention was demonstrated, this invention is not limited to the said embodiment at all. For example, a dehydrogenation reactor according to another embodiment of the present invention may include a reaction chamber, and a first molded body and a second molded body arranged in the reaction chamber, and the first molded body is Pt-supported Al ₂ O ₃ may be included, the second molded body may include TiO _2, and the dehydrogenation reactor may be used for dehydrogenation of a cyclic saturated hydrocarbon having a methyl group. . A dehydrogenation catalyst according to another embodiment of the present invention may include a first molded body and a second molded body, and the first molded body may include Al ₂ O ₃ on which Pt is supported. The shaped body may contain TiO _2, and the dehydrogenation catalyst may be used for dehydrogenation of a cyclic saturated hydrocarbon having a methyl group. A dehydrogenation reactor according to another embodiment of the present invention may include a reaction chamber and a molded body (third molded body) disposed in the reaction chamber. , Pt-supported Al ₂ O ₃ and TiO _2, and the dehydrogenation reactor may be used for dehydrogenation of a cyclic saturated hydrocarbon having a methyl group. The dehydrogenation catalyst according to another embodiment of the present invention may include a molded body (third molded body), and the molded body (third molded body) includes Al ₂ O ₃ supporting Pt and TiO _2. The dehydrogenation catalyst may be used for dehydrogenation of a cyclic saturated hydrocarbon having a methyl group. The manufacturing method of each of the first molded body, the second molded body, and the third molded body may be, for example, rolling granulation, extrusion molding, or tableting molding. The shape of each of the first molded body, the second molded body, and the third molded body is not particularly limited. Each molded body may be spherical or columnar, for example. The cross section of the columnar shaped body may be circular, trilobal, or tetralobal. Each shaped body may be plate-shaped or honeycomb-shaped. The major axis (for example, diameter) of each molded body is not particularly limited, but may be 1 to 4 mm.

  Hereinafter, although the content of the present invention is explained in detail using an example and a comparative example, the present invention is not limited to the following examples.

[Production of first particles]
As the support Al ₂ O ₃ , JRC-ALO-8 which is a kind of Japanese reference catalyst was used. The carrier was pulverized with a planetary ball mill. The solution of Pt compound was attached to the pulverized carrier by the impregnation method. For the Pt compound, tetraammineplatinum (II) nitrate was used. The impregnation method was performed so that the amount of Pt supported on the carrier was 1% by mass. The supported amount of Pt is a supported amount based on the total mass of the carrier. The carrier to which the Pt compound was adhered was fired at a temperature of 673 K to obtain a powdery first raw material. The first raw material was sized to obtain first particles. The sizing was performed according to the following procedure. The first raw material was compression molded with a tableting machine to obtain a molded body. The molded body was lightly crushed using a pestle in a mortar to obtain a pulverized product. The pulverized product was classified with a mesh to obtain first particles. The particle diameter of the first particles was 250 to 500 μm.

[Production of second particles]
JRC-TIO-7, which is a kind of Japanese reference catalyst, was used as the starting material TiO ₂ . The starting material TiO ₂ was pulverized with a planetary ball mill. The pulverized TiO ₂ was fired at a temperature of 673K, 873K, 973K, or 1073K to obtain four types of second raw materials having different firing temperatures. Hereinafter, the second raw material obtained by firing a TiO ₂ at a temperature of 673K, also referred to as "second raw material baking temperature 673K." The second raw material obtained by baking TiO ₂ at a temperature of 873 K is also referred to as “second raw material at a baking temperature of 873 K”. The second raw material obtained by firing TiO ₂ at a temperature of 973K is also referred to as “second raw material having a firing temperature of 973K”. A second raw material obtained by baking TiO ₂ at a temperature of 1073K is also referred to as a “second raw material having a baking temperature of 1073K”.

Using an X-ray diffraction (XRD) apparatus, the XRD patterns of TiO ₂ constituting the four kinds of second raw materials having different firing temperatures obtained above were individually measured. The XRD patterns of the four types of TiO ₂ measured are shown in FIG. As shown in FIG. 4, anatase-type diffraction peaks were observed in all four types of XRD patterns of TiO ₂ . This means that the four types of TiO ₂ are all anatase TiO ₂ . Using the diffraction peak at a diffraction angle 2θ of 25.28 ° derived from the (101) plane of anatase-type TiO ₂ , the crystallite diameter of TiO ₂ after firing was determined according to Scherrer's equation (1). The crystallite diameter of TiO ₂ constituting the second raw material having a firing temperature of 673 K was 14.1 nm. The crystallite diameter of TiO ₂ constituting the second raw material having a firing temperature of 873 K was 23.4 nm. The crystallite diameter of TiO ₂ constituting the second raw material having a firing temperature of 973 K was 33.7 nm. The crystallite diameter of TiO ₂ constituting the second raw material having a firing temperature of 1073K was 52.8 nm. The specific surface area of TiO ₂ after firing was measured by the BET method. The specific surface area of TiO ₂ constituting the second raw material having a firing temperature of 673 K was 118 m ² / g. The specific surface area of TiO ₂ constituting the second raw material having a firing temperature of 873 K was 58 m ² / g. The specific surface area of TiO ₂ constituting the second raw material having a firing temperature of 973 K was 31 m ² / g. The specific surface area of TiO ₂ constituting the second raw material having a firing temperature of 1073 K was 13 m ² / g.

  The four types of second raw materials obtained above were individually sized to obtain four types of second particles. Below, the 2nd particle obtained from the 2nd raw material of calcination temperature 673K is also called "the 2nd particle of calcination temperature 673K." The second particles obtained from the second raw material having a firing temperature of 873K are also referred to as “second particles having a firing temperature of 873K”. The second particles obtained from the second raw material having a firing temperature of 973K are also referred to as “second particles having a firing temperature of 973K”. The second particles obtained from the second raw material having a firing temperature of 1073K are also referred to as “second particles having a firing temperature of 1073K”. Note that the sizing method is the same as that for the first particles. The particle diameters of the four types of second particles were 250 to 500 μm, respectively.

Example 1
25 mg of the first particles and 25 mg of the second particles having a calcination temperature of 673 K were lightly mixed on the medicine-wrapping paper to obtain 50 mg of a dehydrogenation catalyst. The dehydrogenation catalyst was diluted by mixing 50 mg of the obtained dehydrogenation catalyst and 500 mg of SiC. 550 mg of the dehydrogenation catalyst after dilution was placed in the reaction chamber of the fixed bed flow reactor to obtain the dehydrogenation reactor of Example 1. The thickness of the layer of the dehydrogenation catalyst after dilution disposed in the reaction chamber was 4 mm.

(Example 2)
In Example 2, the second particles having a firing temperature of 873K were used instead of the second particles having a firing temperature of 673K. Except for this point, the dehydrogenation catalyst and dehydrogenation reactor of Example 2 were obtained in the same manner as Example 1.

(Example 3)
In Example 3, the second particles having a firing temperature of 973K were used instead of the second particles having a firing temperature of 673K. Except for this point, the dehydrogenation catalyst and dehydrogenation reactor of Example 3 were obtained in the same manner as Example 1.

Example 4
In Example 4, the second particles having a firing temperature of 1073K were used instead of the second particles having a firing temperature of 673K. Except for this point, the dehydrogenation catalyst and dehydrogenation reactor of Example 4 were obtained in the same manner as Example 1.

(Comparative Example 1)
In Comparative Example 1, Al ₂ O ₃ was used instead of TiO ₂ as the starting material for the second material. As Al ₂ O ₃ , JRC-ALO-8, which is a kind of Japanese reference catalyst, was used. Except for the above points, a dehydrogenation catalyst and a dehydrogenation reactor of Comparative Example 1 were obtained in the same manner as in Example 1.

[Measurement of methane production]
The dehydrogenation reaction was performed using each of the dehydrogenation reactors obtained in Examples 1 to 4 and Comparative Example 1 alone. And the methane production amount accompanying a dehydrogenation reaction was measured. The measurement was performed by the following method. A dehydrogenation reaction was performed by supplying a gas composed of methylcyclohexane (MCH), Ar, and N ₂ into the dehydrogenation reactor. The dehydrogenation reaction was performed at a temperature of 623K. The volume ratio MCH: Ar: N ₂ of MCH, Ar, and N ₂ contained in the gas was 6.4: 20: 5. The gas flow rate was 31.4 mL / min. The product discharged from the dehydrogenation reactor was recovered and cooled, and separated into a liquid product and a gaseous product. The liquid product was analyzed with a gas chromatograph-hydrogen flame ionization detector (GC-FID). The gas product was analyzed with a gas chromatograph-thermal conductivity detector (GC-TCD). From the GC area (peak area) of methane contained in the gaseous product, the methane production rate r _CH4 was calculated. r _CH4 is the number of moles of methane produced per unit time. FIG. 5 shows the relationship between the dehydrogenation reaction time and the methane production rate in Examples 1 to 4 and Comparative Example 1. Subsequently, the GC area of the hydrogen contained in the gaseous products (peak area) was calculated production rate _{r H2} of _hydrogen, the ratio _r CH4 _/ of _{r CH4} to the sum of _{r H2} and _{r CH4 (r H2 + r CH4} ) From this, the methane concentration (ppm) in the produced hydrogen was calculated. r _H2 is the number of moles of hydrogen generated per unit time. FIG. 6 shows the relationship between the dehydrogenation reaction time in Examples 1 to 4 and Comparative Example 1 and the methane concentration (ppm) in the produced hydrogen. The smaller the value of r _CH4 or methane concentration (ppm) in the produced hydrogen, the more the demethylation associated with the dehydrogenation reaction is suppressed.

[Measurement of hydrogen yield]
The hydrogen yield in each dehydrogenation reaction of Examples 1 to 4 and Comparative Example 1 was measured. Hydrogen yield and _{r H2} above, and a supply amount _{r MCH} of MCH to the dehydrogenation reactor, was determined according to the following equation (2). r _MCH is the number of moles of MCH supplied per unit time into the dehydrogenation reactor. The relationship between the dehydrogenation reaction time and the hydrogen yield in Examples 1 to 4 and Comparative Example 1 is shown in FIG.
Hydrogen yield (unit:%) = r _H2 / (r _MCH × 3) × 100 (2)

(Example 5)
In Example 5, 25 mg of the first particles and 12.5 mg of the second particles having a calcining temperature of 673 K were mixed to obtain 37.5 mg of a dehydrogenation catalyst. The dehydrogenation catalyst was diluted by mixing 37.5 mg of the obtained dehydrogenation catalyst and 500 mg of SiC. 537.5 mg of the dehydrogenation catalyst after dilution was placed in the reaction chamber of the fixed bed flow reactor. A dehydrogenation catalyst and a dehydrogenation reactor of Example 5 were obtained in the same manner as Example 1 except for the above points.

(Example 6)
In Example 6, 25 mg of the first particles and 50 mg of the second particles having a calcination temperature of 673 K were mixed to obtain 75 mg of a dehydrogenation catalyst. The resulting dehydrogenation catalyst 75 mg and SiC 500 mg were mixed to dilute the dehydrogenation catalyst. 575 mg of the dehydrogenated catalyst after dilution was placed in the reaction chamber of the fixed bed flow reactor. A dehydrogenation catalyst and a dehydrogenation reactor of Example 6 were obtained in the same manner as Example 1 except for the above points.

  In the same manner as in Example 1, the amount of methane produced and the hydrogen yield in the dehydrogenation reactions of Examples 5 and 6 were measured. FIG. 8 shows the relationship between the dehydrogenation reaction time and the methane production rate in Examples 1, 5 and 6. FIG. 9 shows the relationship between the dehydrogenation reaction time in Examples 1, 5, and 6 and the methane concentration (ppm) in the produced hydrogen. The relationship between the dehydrogenation reaction time and the hydrogen yield in Examples 1, 5, and 6 is shown in FIG. As shown in each figure, it was found that Examples 1 to 6 can suppress demethylation associated with the dehydrogenation reaction as compared with Comparative Example 1.

[Production of third particles]
The first raw material and one of the three kinds of second raw materials having different firing temperatures were mixed by a planetary ball mill to obtain the following three kinds of third raw materials. Hereinafter, the third raw material obtained by mixing the first raw material and the second raw material having a baking temperature of 673K is also referred to as “third raw material having a baking temperature of 673K”. The third raw material obtained by mixing the first raw material and the second raw material having a firing temperature of 873K is also referred to as “third raw material having a firing temperature of 873K”. The third raw material obtained by mixing the first raw material and the second raw material having a firing temperature of 1073K is also referred to as “third raw material having a firing temperature of 1073K”. Mixing with the planetary ball mill was performed twice at 300 rpm for 30 minutes. Three types of third raw materials were individually sized to obtain three types of third particles. Below, the 3rd particle obtained from the 3rd raw material of calcination temperature 673K is also called "the 3rd particle of calcination temperature 673K." The third particles obtained from the third raw material having a firing temperature of 873K are also referred to as “third particles having a firing temperature of 873K”. The third particles obtained from the third raw material having a firing temperature of 1073K are also referred to as “third particles having a firing temperature of 1073K”. Note that the sizing method is the same as that for the first particles. The particle sizes of the three types of third particles were 250 to 500 μm, respectively.

(Example 7)
The dehydrogenation catalyst was diluted by mixing 50 mg of the dehydrogenation catalyst consisting only of the third particles having a calcination temperature of 673 K and 500 mg of SiC. 550 mg of the diluted dehydrogenation catalyst was placed in the reaction chamber of the fixed bed flow reactor to obtain the dehydrogenation reactor of Example 7.

(Example 8)
In Example 8, the 3rd particle of calcination temperature 873K was used instead of the 3rd particle of calcination temperature 673K. Except for this point, the dehydrogenation catalyst and dehydrogenation reactor of Example 8 were obtained in the same manner as Example 7.

Example 9
In Example 9, the third particles having a firing temperature of 1073K were used instead of the third particles having a firing temperature of 673K. Except for this point, the dehydrogenation catalyst and dehydrogenation reactor of Example 9 were obtained in the same manner as Example 7.

(Comparative Example 2)
In Comparative Example 2, Al ₂ O ₃ was used in place of TiO ₂ as a starting material for the second raw material. As Al ₂ O ₃ , JRC-ALO-8, which is a kind of Japanese reference catalyst, was used. Except for the above points, the dehydrogenation catalyst and dehydrogenation reactor of Comparative Example 2 were obtained in the same manner as in Example 7.

  In the same manner as in Example 1, the amount of methane produced and the hydrogen yield in the dehydrogenation reactions of Examples 7 to 9 and Comparative Example 2 were measured. The relationship between the dehydrogenation reaction time and the methane production rate in Examples 7 to 9 and Comparative Example 2 is shown in FIG. FIG. 12 shows the relationship between the dehydrogenation reaction time in Examples 7 to 9 and Comparative Example 2 and the methane concentration in the produced hydrogen. FIG. 13 shows the relationship between the dehydrogenation reaction time and the hydrogen yield in Examples 7 to 9 and Comparative Example 2. As shown in each figure, Examples 7 to 9 were found to be able to suppress demethylation associated with the dehydrogenation reaction as compared with Comparative Example 2.

  FIG. 7 is compared with FIG. In Examples 1 and 2 in FIG. 7, the hydrogen yield at the initial stage of the dehydrogenation reaction was relatively small. On the other hand, in Examples 7 and 8 in FIG. 13, compared with Examples 1 and 2 in FIG. 7, the yield of hydrogen was large even at the initial stage of the dehydrogenation reaction. That is, it was confirmed that the dehydrogenation reactor according to the second embodiment has an excellent hydrogen yield at the initial stage of the dehydrogenation reaction as compared with the dehydrogenation reactor according to the first embodiment. However, in Examples 1 and 2 in FIG. 7, the hydrogen yield in the dehydrogenation reaction increased with time, and no significant difference was found from the hydrogen yield in Examples 7 and 8 in FIG. From the comparison between FIG. 5 and FIG. 11 and the comparison between FIG. 6 and FIG. 12, as the dehydrogenation reaction time elapses, the methane production amount of Examples 1 to 3 is the methane production amount of Examples 7 to 9. It was confirmed that there was a tendency to decrease.

[Production of Pt / Al ₂ O ₃ ]
As the support Al ₂ O ₃ , JRC-ALO-8 which is a kind of Japanese reference catalyst was used. A solution of the Pt compound was attached to the support by an impregnation method. For the Pt compound, tetraammineplatinum (II) nitrate was used. The impregnation method was performed so that the amount of Pt supported on the carrier was 1% by mass. The carrier to which the Pt compound was adhered was calcined at a temperature of 673K to obtain Pt / Al ₂ O ₃ for the first catalyst part.

[Production of TiO ₂ ]
As TiO ₂ , JRC-TIO-7, which is a kind of Japanese reference catalyst, was used. TiO ₂ was calcined at a temperature of 673 K to obtain TiO ₂ for the second catalyst part.

(Example 10)
In the reaction chamber of the fixed bed flow reactor, a second catalyst portion (second catalyst layer) made of TiO ₂ and SiC was formed on the MCH supply port side (upstream side). In the reaction chamber, a first catalyst portion (first catalyst layer) made of Pt / Al ₂ O ₃ and SiC was formed on the product outlet side (downstream side). The MCH supply port side was disposed vertically upward, and the product discharge port side was disposed vertically downward. That is, the second catalyst layer was stacked on the first catalyst layer in the reaction chamber. A layer made of silica wool was disposed between the first catalyst layer and the second catalyst layer. The first catalyst layer and the second catalyst layer are completely separated by a layer made of silica wool. The dehydrogenation reactor of Example 10 was obtained by the above procedure. The thickness of the first catalyst layer was 4 mm. The thickness of the second catalyst layer was 4 mm. The thickness of the layer made of silica wool was 1 mm. The mass of Pt / Al ₂ O ₃ in the first catalyst layer was 25 mg. The mass of SiC in the first catalyst layer was 250 mg. The mass of TiO ₂ in the second catalyst layer was 25 mg. The mass of SiC in the second catalyst layer was 250 mg.

(Example 11)
In Example 11, the first catalyst portion (first catalyst layer) made of Pt / Al ₂ O ₃ and SiC was formed on the MCH supply port side (upstream side). Also, to form the second catalyst part composed of TiO ₂ and SiC (second catalyst layer) on the outlet side of the product (the downstream side). That is, in Example 11, the first catalyst layer was overlaid on the second catalyst layer. A dehydrogenation reactor of Example 11 was obtained in the same manner as Example 10 except for the above points.

  In the same manner as in Example 1, the amount of methane produced and the hydrogen yield in the dehydrogenation reactions of Examples 10 and 11 were measured. The relationship between the dehydrogenation reaction time and the methane production rate in Examples 10 and 11 is shown in FIG. The relationship between the dehydrogenation reaction time in Examples 10 and 11 and the methane concentration (ppm) in the produced hydrogen is shown in FIG. FIG. 16 shows the relationship between the dehydrogenation reaction time and the hydrogen yield in Examples 10 and 11.

  5 and 11 were compared with FIG. 14, it was found that Examples 10 and 11 had a lower methane production rate than Comparative Examples 1 and 2. 6 and 12 were compared with FIG. 15, it was found that Examples 10 and 11 had a smaller amount of methane produced per dehydrogenation activity than Comparative Examples 1 and 2. That is, it was found that Examples 10 and 11 can suppress demethylation associated with the dehydrogenation reaction as compared with Comparative Examples 1 and 2.

(Example 12)
A dehydrogenation reactor of Example 12 was obtained in the same manner as in Example 10 except that the thickness of the layer made of silica wool was changed to 4 mm.

In the same manner as in Example 1, the amount of methane produced and the hydrogen yield in the dehydrogenation reaction of Example 12 were measured. The measurement result of Example 12 was the same as the measurement result of Example 10. From the obtained measurement results, it was found that Example 12 can suppress demethylation associated with the dehydrogenation reaction as compared with Comparative Examples 1 and 2. From the measurement results of Examples 10 to 12, TiO ₂ and Pt / Al ₂ O ₃ are not in direct contact and dehydrogenation proceeds even when they are separated from each other, and demethylation accompanying dehydrogenation reaction Has been demonstrated to be suppressed.

  Hydrogen gas produced by dehydrogenation of cyclic saturated hydrocarbons using the dehydrogenation catalyst and dehydrogenation reactor according to the present invention is used as fuel for fuel cell vehicles, for example.

  2a, 2b, 20a, 20b ... dehydrogenation reactor, 4 ... reaction chamber, 6,14,22 ... dehydrogenation catalyst, 8a ... first particle, 8b ... second particle, 10 ... cyclic saturated hydrocarbon having a methyl group , 12 ... product, 14a ... third particles, 24 ... first catalyst part, 26 ... second catalyst part, 28 ... supply port, 30 ... discharge port, 44 ... gas-liquid separator, 46 ... hydrogen purifier, 54 ... high pressure compressor, 56 ... tank, 100 ... hydrogen production system.

Claims (18)

A reaction chamber;
Al ₂ O ₃ loaded with Pt disposed in the reaction chamber;
TiO ₂ disposed in the reaction chamber;
With
A dehydrogenation reactor used for dehydrogenation of a cyclic saturated hydrocarbon having a methyl group. The reaction chamber; a first catalyst portion and a second catalyst portion disposed in the reaction chamber;
With
The first catalyst part includes Al ₂ O ₃ on which Pt is supported,
The second catalyst part includes TiO ₂ ;
The dehydrogenation reactor according to claim 1. A supply port for the cyclic saturated hydrocarbon is formed in the reaction chamber;
A discharge port for the product generated in the reaction chamber is formed in the reaction chamber,
The second catalyst part is located between the supply port and the discharge port;
The first catalyst part is located between the second catalyst part and the outlet;
The dehydrogenation reactor according to claim 2. The reaction chamber; first particles and second particles disposed in the reaction chamber;
With
The first particles include Al ₂ O ₃ on which Pt is supported,
The second particles include TiO ₂ ;
The first particles and the second particles are mixed in the reaction chamber;
The dehydrogenation reactor according to claim 1. The reaction chamber; and third particles disposed in the reaction chamber;
With
The third particles are
Al ₂ O ₃ supported with Pt;
TiO ₂ and
including,
The dehydrogenation reactor according to claim 1. The crystallite diameter of the TiO ₂ is 35 nm or less,
The dehydrogenation reactor according to claim 4 or 5. A method for producing a dehydrogenation reactor according to claim 4, comprising:
Sizing the first raw material containing Pt-supported Al ₂ O ₃ to obtain the first particles;
Sizing a _second raw material containing TiO ₂ to obtain the second particles;
Mixing the first particles and the second particles;
Comprising
A method for producing a dehydrogenation reactor. A method for producing a dehydrogenation reactor according to claim 5, comprising:
Mixing a first raw material containing Al ₂ O ₃ supported with Pt and a second raw material containing TiO ₂ to obtain a third raw material containing the first raw material and the second raw material;
Sizing the third raw material to obtain the third particles;
Comprising
A method for producing a dehydrogenation reactor. The crystallite diameter of the TiO ₂ is 35 nm or less,
The method for producing a dehydrogenation reactor according to claim 7 or 8. Al ₂ O ₃ supported with Pt;
TiO ₂ and
With
A dehydrogenation catalyst used for dehydrogenation of a cyclic saturated hydrocarbon having a methyl group. First particles and second particles,
The first particles include Al ₂ O ₃ on which Pt is supported,
The second particles include TiO ₂ ;
The first particles and the second particles are mixed,
The dehydrogenation catalyst according to claim 10. Comprising third particles,
The third particles are
Al ₂ O ₃ supported with Pt;
TiO ₂ and
including,
The dehydrogenation catalyst according to claim 10. The crystallite diameter of the TiO ₂ is 35 nm or less,
The dehydrogenation catalyst according to claim 11 or 12. A method for producing the dehydrogenation catalyst according to claim 11, comprising:
Sizing the first raw material containing Pt-supported Al ₂ O ₃ to obtain the first particles;
Sizing a _second raw material containing TiO ₂ to obtain the second particles;
Mixing the first particles and the second particles;
Comprising
A method for producing a dehydrogenation catalyst. A method for producing the dehydrogenation catalyst according to claim 12, comprising:
Mixing a first raw material containing Al ₂ O ₃ supported with Pt and a second raw material containing TiO ₂ to obtain a third raw material containing the first raw material and the second raw material;
Sizing the third raw material to obtain the third particles;
Comprising
A method for producing a dehydrogenation catalyst. The crystallite diameter of the TiO ₂ is 35 nm or less,
The method for producing a dehydrogenation catalyst according to claim 14 or 15. Comprising the dehydrogenation reactor according to any one of claims 1 to 6,
Hydrogen production system. In the dehydrogenation reactor according to any one of claims 1 to 6, comprising a step of generating hydrogen by dehydrogenation of the cyclic saturated hydrocarbon,
A method for producing hydrogen.