JP2016059845A - Catalyst for hydrogen production, production process therefor, and fuel cell system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a catalyst for hydrogen production that can exhibit a sufficient catalytic activity without the use of an expensive metal such as platinum, gold, palladium and rhodium, and also without preforming a reduction treatment as a pre-treatment; a production process for said catalyst; and a fuel cell system including a reformer comprising said catalyst.SOLUTION: Provided is a catalyst for hydrogen production containing: a carrier containing an oxide represented by the following composition formula (I); and a nickel. LaBaAlO(here, 0.05≤x≤0.5) (I).SELECTED DRAWING: None

Description

  The present invention relates to a hydrogen production catalyst, a production method thereof, and a fuel cell system.

  Conventionally, a method using a reforming reaction such as a steam reforming reaction is known as a method for reforming an organic compound such as a hydrocarbon compound to convert it into synthesis gas or hydrogen. As a reforming catalyst used for such a reforming reaction, a nickel-based catalyst and a ruthenium-based catalyst are known (see Patent Documents 1 and 2).

  The conventional reforming catalyst needs to be subjected to a reduction treatment as a pretreatment before being subjected to the reforming reaction after the calcination treatment for supporting the active metal on the carrier. This is because the active metal (for example, nickel) is oxidized into an oxide (for example, NiO) and the catalytic activity is lost during the firing process.

A reforming catalyst capable of omitting the pretreatment has also been studied. For example, a composition formula La _1-x Sr _x AlO ₃ [wherein x represents 0.05 to 0.5. A reforming catalyst is proposed in which Ni and a metal element selected from the group consisting of platinum, gold, palladium and rhodium are supported on a carrier containing an oxide represented by the formula (Patent Document 3). reference).

JP 2000-084410 A JP 2010-066944 A JP 2012-110828 A

  However, since metals such as platinum, gold, palladium, and rhodium are expensive, the use of such metals tends to increase the manufacturing cost.

  The present invention has been made in view of the above problems, and exhibits a sufficient catalytic activity without using an expensive metal such as platinum, gold, palladium and rhodium and without performing a reduction treatment as a pretreatment. It is an object of the present invention to provide a hydrogen production catalyst, a method for producing the catalyst, and a fuel cell system including a reformer including the catalyst.

The present invention provides a hydrogen production catalyst comprising a support containing an oxide represented by the following composition formula (I) and nickel (Ni).
La _1-x Ba _x AlO ₃ (where 0.05 ≦ x ≦ 0.5) (I)

  The catalyst according to the present invention can exhibit a sufficient catalytic activity without using an expensive active metal and without performing a reduction treatment as a pretreatment. As a result, the catalyst according to the present invention is cheaper compared to conventional reforming catalysts that require expensive active metals, and has fewer steps than conventional catalysts that require pretreatment. The production of hydrogen can be started with fewer steps.

  The reason why the catalyst according to the present invention exhibits sufficient catalytic activity without performing a reduction treatment is not necessarily clear, but due to barium (Ba) contained in the oxide represented by the composition formula (I), Ni This is thought to be due to the promotion of reduction. Furthermore, the catalyst according to the present invention can maintain high catalytic activity over a long period of time by maintaining the reduced state of Ni.

  The oxide represented by the above composition formula (I) preferably exhibits a maximum diffraction peak in the range of 2θ of 33 ° to 34 ° in the powder X-ray diffraction spectrum of the oxide. An oxide having a maximum diffraction peak in the above range in the powder X-ray diffraction spectrum has a perovskite structure and is excellent in terms of reducing Ni.

In the catalyst according to the present invention, the hydrogen production catalyst obtained was analyzed by ICP emission spectrometry to moles _{n Ni} of Ni, the ratio _n Ba _{/ n Ni} molar number _{n Ba} and Ba is 0.01 It is preferable that it is 20 or less. When the molar ratio _nBa / _nNi is in the above range, sufficient catalytic activity can be easily obtained without performing a reduction treatment as a pretreatment.

  The present invention also provides a fuel cell system comprising a reforming unit that reforms a reforming raw material containing hydrocarbon compounds into a reformed gas containing hydrogen. A fuel cell system including the catalyst is provided.

  According to the present invention, a catalyst for hydrogen production that can exhibit sufficient catalytic activity without using an expensive metal such as platinum, gold, palladium, and rhodium and without performing a reduction treatment as a pretreatment, A method for producing a catalyst and a fuel cell system including a reforming unit including the catalyst can be provided.

It is a conceptual diagram which shows an example of the fuel cell system which concerns on embodiment of this invention. 3 is a diagram showing a powder X-ray diffraction pattern of a catalyst carrier 2. FIG.

  Preferred embodiments of the catalyst for hydrogen production according to the present invention will be described below.

The catalyst according to this embodiment contains a support containing an oxide represented by the following composition formula (I) and Ni.
La _1-x Ba _x AlO ₃ (where 0.05 ≦ x ≦ 0.5) (I)

  In this specification, the periodic table refers to a long-period element periodic table defined by IUPAC.

Examples of the oxide according to this embodiment include an oxide having a perovskite structure. Here, the perovskite structure is a crystal structure that can be formed by an oxide represented by the composition formula ABO _{3. In the} composition formula, A represents a rare earth element and / or an alkaline earth metal element, and the like. Represents a typical metal element and / or a transition metal element.

  The catalyst according to this embodiment can exhibit high catalytic activity and coking resistance even when Ni is used as the active metal by including a support containing an oxide having the above structure.

In the oxide according to this embodiment, the A site of LaAlO ₃ is substituted with Ba. The substitution rate (x) of Ba is 0.05 to 0.5, may be 0.05 to 0.3, and may be 0.1 to 0.3. Note that substitution rate (x) can also be referred to as the ratio _N Ba atomic number _{N Ba} to the total number of atoms _{N Ba} atomic number _{N La} and Ba of La in the oxide _{/ (N La + N Ba)} . When the substitution rate is larger than 0.5, the effect of the present invention cannot be sufficiently obtained. The present inventors speculate that this is because the perovskite structure collapses when the substitution rate exceeds 0.5. Moreover, there exists a tendency for a catalyst activity to improve that a substitution rate is 0.05 or more.

In the powder X-ray diffraction spectrum, the oxide according to the present embodiment preferably exhibits a maximum diffraction peak in a range where 2θ is 33 ° or more and 34 ° or less. In the oxide according to this embodiment, the maximum diffraction peak in the powder X-ray diffraction spectrum is shifted to a lower angle side than the maximum diffraction peak in the powder X-ray diffraction spectrum of LaAlO ₃ , but the maximum diffraction peak is in the above range. If present, it has a perovskite structure and is excellent in terms of reducing Ni. The powder X-ray diffraction spectrum is measured by X-ray irradiation of λ = 1.5406１．５ with a Cu target using RINT2500 manufactured by Rigaku (radiation source: CuKα, using a monochromator, voltage 50 KV, power source 200 mA).

  The method for producing the oxide according to the present embodiment is not particularly limited. For example, the solid phase reaction method, the complex polymerization method, the hydrolysis method, the sol-gel method, the hydrothermal method, the spray pyrolysis method, the common method. For example, a sedimentation method. A known method can be used for these.

  In the case of the solid phase reaction method, for example, a compound containing a metal element (La, Ba and Al) contained in the target oxide (for example, oxide, carbonate, organic substance, etc.) is used as a starting material, and the target is used. The target oxide can be obtained by mixing and firing so that the metal element ratio is the same as that of the oxide. The specific firing temperature and firing time may be the conditions under which the target oxide is formed. Examples of the firing temperature and firing time include conditions for firing for about 10 to 40 hours in a temperature range of about 1200 to 1500 ° C. In the case of using a carbonate, an organic compound, or the like as a raw material, it is preferable to pre-fire before firing to decompose the raw material, and then fire to form the target oxide. When carbonate is used as a raw material, for example, after calcining at about 1000 to 1200 ° C. for about 10 hours, it can be fired under the above-described conditions. The firing means is not particularly limited, and any means such as an electric heating furnace or a gas heating furnace can be adopted. The firing atmosphere may normally be an oxidizing atmosphere such as in an oxygen stream or in the air. However, when the source material contains a sufficient amount of oxygen, for example, firing may be performed in an inert atmosphere. .

  In the case of the coprecipitation method, for example, a mixed salt aqueous solution containing La salt, Ba salt and Al salt in a predetermined stoichiometric ratio is prepared so as to obtain a target oxide. A neutralizing agent is added to the aqueous solution for coprecipitation, and the obtained coprecipitate is dried and then heat-treated to obtain a desired oxide powder.

  Examples of the salt of La, the salt of Ba, and the salt of Al include inorganic salts such as sulfate, nitrate, chloride, and phosphate, and organic acid salts such as acetate and oxalate. Further, the mixed salt aqueous solution can be prepared, for example, by adding the salt of each element to water at a ratio that gives a predetermined stoichiometric ratio and stirring and mixing.

  Thereafter, a neutralizing agent is added to the mixed salt aqueous solution to cause coprecipitation. Examples of the neutralizing agent include ammonia, for example, organic bases such as amines such as triethylamine and pyridine, and inorganic bases such as caustic soda, caustic potash, potassium carbonate, and ammonium carbonate. The neutralizing agent is preferably added so that the pH of the solution after adding the neutralizing agent is about 6 to 10.

  The obtained coprecipitate can be washed with water if necessary, and dried by, for example, vacuum drying or ventilation drying, and then heat-treated at, for example, about 500 to 1000 ° C, preferably about 600 to 950 ° C.

  In the case of the sol-gel method, for example, the target oxide can be prepared by the following method. That is, La salt, Ba salt and Al salt, citric acid, ethylene glycol, and pure water are mixed and stirred well, and heated to moisture so that the same metal element ratio as the target oxide is obtained. Remove. Thereafter, the nitrate is decomposed by holding at about 300 ° C. to 500 ° C. for about 1 to 5 hours, and then held at 700 ° C. to 900 ° C. for about 5 to 20 hours to burn and remove citric acid and ethylene glycol. Thus, the target oxide can be obtained. Examples of the La salt, Ba salt, and Al salt include the inorganic salts and organic acid salts described above.

  In the present embodiment, the carrier may be fired in an air atmosphere or an oxygen atmosphere before supporting Ni. The firing temperature at this time is usually 500 ° C. to 1500 ° C., preferably 700 ° C. to 1200 ° C.

  The carrier according to the present embodiment may use the oxide represented by the composition formula (I) as it is, an inorganic binder containing alumina, silica, zirconia, zeolite, etc., carbonized, hydrocarbon-based, polymer-based It can also be mixed with an organic binder containing the compound.

  The catalyst according to this embodiment contains the carrier and Ni.

  The catalyst according to this embodiment can be obtained, for example, by supporting Ni on the carrier according to this embodiment described above.

  The method for supporting Ni on the carrier is not particularly limited, and can be easily performed by applying a known method. Examples of the supporting method include an impregnation method, a deposition method, a coprecipitation method, a kneading method, an ion exchange method, and a pore filling method, and among these, the impregnation method and the pore filling method are preferable. The starting material of the supported metal can be selected as appropriate, but usually a supported metal chloride or nitrate is used.

  For example, when an impregnation method is applied, a solution of a salt of Ni (usually an aqueous solution) is prepared, and the carrier is impregnated with the prepared solution so as to obtain a target loading amount. Then, the support | carrier is dried and the catalyst by which Ni was carry | supported can be obtained by baking as needed. Firing is usually performed in an air atmosphere or an oxygen atmosphere. The firing temperature is not particularly limited as long as it is equal to or higher than the decomposition temperature of the Ni salt, but is usually about 200 ° C to 1000 ° C, preferably about 300 to 800 ° C. The firing time varies depending on the firing temperature, but is usually 30 minutes to 30 hours, preferably about 1 to 20 hours.

  In the catalyst according to the present embodiment, the content of Ni contained in the catalyst is preferably 0.05 to 20% by mass, in terms of metal atoms, based on the total mass of the catalyst, and is 1 to 15% by mass. More preferably. If the Ni content is 20% by mass or less, metal aggregation is unlikely to occur. Therefore, it is possible to suppress a reduction in the proportion of Ni appearing on the catalyst surface due to metal aggregation. Further, the Ni content is 0.05%. A higher catalytic activity can be obtained when the content is at least mass%. Thereby, it is not necessary to use a large amount of catalyst, and the enlargement of the reactor can be avoided.

  Further, the catalyst according to the present embodiment further includes one or more metals selected from the group consisting of barium, calcium, strontium, platinum, gold, palladium, and rhodium (hereinafter referred to as “specific metal element”). You may go out.

  When the catalyst according to the present embodiment further includes the specific metal element, the specific metal element may be supported on the carrier according to the present embodiment. The method of supporting the specific metal element on the carrier according to the present embodiment may be a method of separately supporting Ni on the carrier and supporting the specific metal element on the carrier. The method of performing may be sufficient. When supporting Ni on the carrier and supporting the specific metal element on the carrier separately, after the Ni is supported on the carrier, the specific metal element may be supported on the Ni-supported carrier. preferable.

In the catalyst according to the present embodiment, the hydrogen production catalyst inductively coupled plasma emission spectrometry determined by analyzing the (ICP emission spectral analysis) to moles n _Ni of Ni, the number of moles n _Ba and Ba The ratio n _Ba / n _Ni may be 0.01 or more and 20 or less, may be 0.05 or more and 20 or less, and may be 0.01 or more and 15 or less. When the molar ratio _nBa / _nNi is in the above range, sufficient catalytic activity can be exhibited without performing reduction treatment as pretreatment. As the measuring device, for example, Optima4300DV manufactured by PerkinElmer, Inc. can be used.

In this embodiment, the molar ratio n _{Ba /} n _Ni may be the number of moles of Ba contained in the oxide to moles n _Ni of Ni contained in the catalyst. In that case, the molar ratio _nBa / _nNi may be 0.01 or more and 20 or less.

In the present embodiment, in order to adjust the molar ratio n _{Ba /} n _Ni within a range of purposes, for example, the number of moles n _Ni of Ni calculated from the amount of Ni compounds to be impregnated into the carrier, an oxide used in the carrier The number of _Ba moles nBa calculated from the amount of Ba salt used in preparing the solution may be adjusted so as to fall within the above range.

Surface area of the catalyst according to the present embodiment is not particularly limited, is preferably from 5 to 200 m ² / g, and more preferably 10 to 150 m ² / g.

  The shape of the catalyst according to the present embodiment is not particularly limited, and can be appropriately selected depending on the form in which the catalyst is used. As the shape, for example, an arbitrary shape such as a pellet shape, a granule shape, a honeycomb shape, or a sponge shape is adopted.

  The catalyst according to this embodiment is used for production of hydrogen. For example, it can be used to reform a raw material containing hydrocarbon compounds into a reformed gas containing hydrogen. Hereinafter, a method for producing a reformed gas containing hydrogen using the catalyst according to the present embodiment will be described.

  The method for producing a reformed gas according to the present embodiment includes a step of bringing a reforming raw material containing hydrocarbon compounds into contact with the catalyst according to the present embodiment to reform the reformed gas containing hydrogen. .

  Specifically, for example, in the presence of the catalyst according to the present embodiment, a raw material containing hydrocarbon compounds and a gas containing at least one selected from water (steam), oxygen and carbon dioxide, The mixed reforming raw material is supplied and modified by a known hydrogen production reaction, for example, at least one hydrogen production reaction selected from a steam reforming reaction, a partial oxidation reaction, an autothermal reforming reaction, and a carbon dioxide reforming reaction. A method for producing a quality gas is mentioned.

  The reforming raw material may include steam and hydrocarbon compounds when reforming by a steam reforming reaction, and may include oxygen and hydrocarbon compounds when reforming by a partial oxidation reaction. When reforming by autothermal reforming reaction, water, oxygen and hydrocarbon compounds may be included, and when reforming by carbon dioxide reforming reaction, carbon dioxide and hydrocarbon compounds may be included. . The reforming raw material may further contain hydrogen, carbon monoxide, or nitrogen.

  Examples of the reaction mode of the reaction using the catalyst according to the present embodiment include a fixed bed type, a moving bed type, and a fluidized bed type, and are not particularly limited.

  In the present embodiment, the catalyst according to the present embodiment can exhibit a sufficient catalytic activity without performing a pretreatment, but a catalyst that has been subjected to a reduction treatment of the catalyst may be used as the pretreatment. The reduction treatment can be performed, for example, by holding at 400 to 1000 ° C., preferably 400 to 800 ° C. in a reducing atmosphere such as a hydrogen atmosphere.

In the present embodiment, the space velocity of the reforming raw material introduced into the catalyst is preferably a gas space velocity (hereinafter referred to as GHSV), preferably ^{1 to} 10,000 h ⁻¹ , more preferably 10 to 5,000 h ⁻¹ , More preferably, it is the range of 50-3,000h- ¹ . When GHSV is 10,000 h ⁻¹ or less, it is preferable because the contact time between the reforming raw material and the catalyst can be sufficiently secured and the reaction can easily proceed. On the other hand, when GHSV is 10 h ⁻¹ or more, a sufficient amount of hydrogen can be produced with respect to the catalyst amount, and high hydrogen production efficiency is obtained, which is preferable. The liquid space velocity (hereinafter referred to as LHSV) is preferably 0.05 to 5.0 h ⁻¹ , more preferably 0.1 to 2.0 h ⁻¹ , and still more preferably 0.2 to 1.0 h ⁻¹ . It is a range. When the LHSV is 5.0 h ⁻¹ or less, it is preferable because the contact time between the reforming raw material and the catalyst can be sufficiently secured and the reaction easily proceeds. On the other hand, when LHSV is 0.05 h ⁻¹ or more, a sufficient amount of hydrogen can be produced with respect to the amount of catalyst, and high hydrogen production efficiency is obtained, which is preferable.

  Although the reaction temperature in the manufacturing method of the reformed gas which concerns on this embodiment is not specifically limited, It is preferable that it is 200 to 800 degreeC, and it is more preferable that it is 300 to 700 degreeC. In addition, the reaction temperature here refers to the average temperature of the whole catalyst layer. When the reaction temperature is 800 ° C. or lower, it is preferable that the metal contained in the catalyst hardly aggregates and the performance of the catalyst is maintained over a long period of time. On the other hand, it is preferable that the reaction temperature is 200 ° C. or higher because a reaction rate sufficient for hydrogen production can be obtained.

  The reaction pressure in the method for producing a reformed gas according to the present embodiment is not particularly limited, but is preferably normal pressure to 5 MPa, and more preferably normal pressure to 1 MPa. Although it is possible to carry out at a pressure lower than the atmospheric pressure or a pressure higher than 20 MPa, in that case, it is necessary for the production equipment to cope with reduced pressure and high pressure, which is not economically preferable.

  When reforming by steam reforming reaction or autothermal reforming reaction, the amount of steam introduced together with the raw material is the ratio of the number of moles of water molecules to the number of moles of carbon atoms contained in the hydrocarbon compounds (steam / carbon ratio: (Hereinafter referred to as S / C) is preferably set in the range of 1 to 5, more preferably 1 to 3. If the steam / carbon ratio is 1 or more, coke hardly accumulates on the catalyst, and a reformed gas having a high hydrogen content tends to be obtained. A steam / carbon ratio greater than 5 is not preferable because the energy required for supplying steam and the cost required for generating / recovering excess steam become too large.

When reforming by partial oxidation reaction or autothermal reforming reaction, the amount of oxygen introduced together with the raw materials is the ratio of the number of moles of oxygen molecules to the number of moles of carbon atoms contained in the hydrocarbon compounds (oxygen / carbon ratio: below O ₂ / C) is preferably 0.8 or less, more preferably 0.5 or less, and even more preferably 0.3 or less. When O ₂ / C is 0.8 or less, the production reaction of carbon dioxide and water is difficult to proceed, which is not preferable because the production amount of hydrogen does not decrease.

  The hydrocarbon compounds contained in the raw material contain an organic compound having 1 to 40 carbon atoms, preferably 1 to 30 carbon atoms, more preferably 1 to 6 carbon atoms. Specific examples include saturated aliphatic hydrocarbons, unsaturated aliphatic hydrocarbons, aromatic hydrocarbons, etc. In addition, saturated aliphatic hydrocarbons and unsaturated aliphatic hydrocarbons are linear or cyclic. Any shape can be used. Such hydrocarbon compounds can contain substituents. The substituent may be either a chain or a ring, and examples thereof include an alkyl group, a cycloalkyl group, an aryl group, an alkylaryl group, and an aralkyl group. In addition, these hydrocarbon compounds may have a substituent having one or more hetero atoms such as oxygen, nitrogen, halogen, and sulfur. Examples of such a substituent include a halogen atom (-F, -Cl, -Br, -I), hydroxyl group (-OH), alkoxy group (-OR), carboxyl group (-COOH), ester group (-COOR), aldehyde group (-CHO), acyl group (-C ( = O) R) and the like.

  Specific examples of the hydrocarbon compounds include chain saturated aliphatic hydrocarbons such as methane, ethane, propane, butane, pentane, hexane, heptane, and octane and their structural isomers, ethylene, propylene, butene, pentene, hexene. Chain unsaturated aliphatic hydrocarbons such as heptene and octene and their structural isomers, cyclic hydrocarbons such as cyclopentane, cyclohexane, cycloheptane and cyclooctane and their structural isomers, benzene, toluene, xylene, naphthalene, And aromatic hydrocarbons such as biphenyl. Moreover, the material which contains these as a single item or a mixture can be used. Examples thereof include city gas, natural gas, LPG, naphtha, gasoline, kerosene, and light oil.

  In addition, as hydrocarbon compounds having a substituent containing a hetero atom, raw materials containing alcohols, ethers, biofuels, and the like can also be used. Examples of the alcohols include methanol and ethanol. Examples of the ethers include dimethyl ether and the like. Examples of the biofuel include biogas, bioethanol, biodiesel, and biojet. Etc.

  When the raw material contains a sulfur content, it is preferable to perform a desulfurization treatment of the raw material containing hydrocarbon compounds before bringing the raw material containing hydrocarbon compounds into contact with the catalyst according to the present embodiment. A desulfurization process can be performed by making the raw material containing hydrocarbon compounds and a desulfurization catalyst contact, for example. The desulfurization catalyst may be, for example, a catalyst containing copper and zinc, or a catalyst containing nickel and zinc.

  In addition to hydrocarbon compounds, raw materials containing hydrogen, water, carbon dioxide, carbon monoxide, oxygen, nitrogen and the like can also be used as raw materials. For example, when hydrodesulfurization is performed as a pretreatment of the raw material, the hydrogen residue used in the reaction can be used as it is without being particularly separated.

  The reformed gas obtained by the method for producing a reformed gas according to the present embodiment can be used as a fuel for a fuel cell as it is when used in a solid oxide fuel cell or a molten carbonate fuel cell. . Moreover, when removal of carbon monoxide is required as in a phosphoric acid fuel cell or a polymer electrolyte fuel cell, it can be suitably used as a raw material for producing the fuel cell hydrogen. This removal of carbon monoxide may employ a known carbon monoxide selective removal method. Examples of the method for selectively removing carbon monoxide include a shift step, a CO selective oxidation step, or a combination thereof.

  The shift step is a step of reacting carbon monoxide with water to convert it into hydrogen and carbon dioxide, and a catalyst containing a mixed oxide of Fe—Cr, a mixed oxide of Zn—Cu, platinum, ruthenium, iridium, etc. The carbon monoxide content is preferably reduced to 2% by volume or less, more preferably 1% by volume or less, and further preferably 0.5% by volume or less on a dry basis. Usually, in the phosphoric acid fuel cell, the mixed gas in this state can be used as fuel.

  In the CO selective oxidation step, a catalyst containing iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium, platinum, copper, silver, gold, or the like is used, and the amount of carbon monoxide remaining is preferably about 0.1. Carbon monoxide concentration by selectively converting carbon monoxide to carbon dioxide by adding 5 to 10 times mol, more preferably 0.7 to 5 times mol, more preferably 1 to 3 times mol of oxygen. Reduce. In this case, the carbon monoxide concentration can be reduced by reacting with the coexisting hydrogen simultaneously with the oxidation of carbon monoxide to generate methane.

  The method for producing reformed gas according to this embodiment described above can also be used as a method for producing hydrogen.

  Next, a hydrogen production apparatus and a fuel cell system in which the catalyst according to this embodiment is used will be described in detail with reference to the drawings.

  A hydrogen production apparatus according to the present embodiment includes, for example, a hydrogen production catalyst according to the present embodiment, and reforms a reforming raw material containing hydrocarbon compounds into a reformed gas containing hydrogen. And a supply unit 20 for supplying a reforming raw material containing hydrocarbon compounds and a gas containing at least one selected from water (steam), oxygen and carbon dioxide to the reforming unit. You may be prepared.

  The reforming unit according to the present embodiment may include a reformer 7. A well-known thing can be used for the container of the reformer 7 which concerns on this embodiment, and there is no restriction | limiting in particular.

  The supply unit 20 according to the present embodiment may include a water tank 1, a water pump 2, a fuel tank 3, and a desulfurizer 5, a reforming raw material containing hydrocarbon compounds in the reforming unit, water (Steam) may be provided as long as it supplies at least one gas selected from oxygen and carbon dioxide.

  The fuel cell system according to the present embodiment includes, for example, a reforming unit according to the present embodiment, a supply unit 20 that supplies a reforming material into the reforming unit, and a fuel cell that is supplied with hydrogen generated in the reforming unit. 16 may be provided.

  In FIG. 1, the raw material containing hydrocarbon compounds in the fuel tank 3 is supplied to a desulfurizer 5 via a fuel pump 4. The desulfurizer 5 desulfurizes hydrocarbon compounds. The desulfurizer 5 may be filled with, for example, the above-described desulfurization catalyst. Hydrogen desulfurization may be performed by supplying hydrogen gas into the desulfurizer 5. This hydrogen gas is supplied from at least one of a gas downstream of the reformer 7, a gas downstream of the shift reactor 9, a gas downstream of the reactor 10 that performs selective oxidation of carbon monoxide, and an anode off gas. Also good. The desulfurized hydrocarbon compounds are supplied to the vaporizer 6 to obtain a vaporized reforming raw material. The reforming raw material is supplied to the reformer 7.

  When reforming by the steam reforming method, the desulfurized hydrocarbon compounds may be mixed with water before being supplied to the vaporizer 6. Water is supplied from the water tank 1 via the water pump 2. When reforming by a partial oxidation reforming method, the desulfurized hydrocarbon compounds may be mixed with oxygen. When the reforming is performed by the autothermal reforming method, the desulfurized hydrocarbon compounds may be mixed with water and oxygen. When reforming by the carbon dioxide reforming method, the desulfurized hydrocarbon compounds may be mixed with carbon dioxide.

  The interior of the reformer 7 may be heated by a burner 17. The fuel of the burner 17 may be a raw material containing hydrocarbon compounds supplied from the fuel tank 3 or an anode off gas.

  The reformed gas produced in this way can be used as a fuel for a fuel cell as it is when used in a solid oxide fuel cell or a molten carbonate fuel cell. When it is necessary to remove carbon monoxide as in a phosphoric acid fuel cell or a polymer electrolyte fuel cell, the reaction undergoes selective oxidation of carbon monoxide after passing through a shift reactor 9 that performs a water gas shift reaction. Pass through vessel 10. As a result, the concentration of carbon monoxide in the reformed gas is reduced to a level that does not affect the characteristics of the fuel cell. That is, the reformed gas becomes a hydrogen gas having a purity suitable for use in a fuel cell. This hydrogen gas is supplied to the fuel cell 16.

  When the fuel cell 16 is, for example, a solid polymer fuel cell, the fuel cell 16 includes an anode 11, a cathode 12, and a solid polymer electrolyte 13, and the anode 11 side has a high purity obtained by the above method. The fuel gas containing hydrogen is introduced into the cathode 12 after the air sent from the air blower 8 is appropriately humidified if necessary (a humidifier is not shown). At this time, a reaction in which hydrogen gas becomes protons and emits electrons proceeds at the anode 11, and a reaction in which oxygen gas obtains electrons and protons to become water proceeds at the cathode 12. In order to promote these reactions, platinum black and Pt catalyst or Pt-Ru alloy catalyst supported on activated carbon are used for the anode 11, and platinum black and Pt catalyst supported on activated carbon are used for the cathode 12, respectively. Usually, both the anode 11 and cathode 12 catalysts are formed into a porous catalyst layer together with polytetrafluoroethylene, a low molecular weight polymer electrolyte membrane material, activated carbon or the like as required. The electric load 14 is electrically connected to the anode 11 and the cathode 12. The anode off gas is consumed in the burner 17. The cathode off gas is discharged from the exhaust port 15.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment. For example, as the fuel cell 16, any other known battery can be used as long as it can generate power using the reformed gas.

  EXAMPLES Hereinafter, although an Example demonstrates this invention more concretely, this invention is not limited to an Example.

[Preparation of catalyst carrier 1]
_{La (NO 3) 3 · 6H} 2 O 9.82g, Ba (NO 3) 2 0.66g, Al (NO 3) 3 · 9H 2 O 9.45g, 31.76g citric acid, ethylene glycol 9.38g and 200 g of pure water was mixed and stirred well, and then heated to remove moisture. Next, after maintaining the temperature at 400 ° C. for 2 hours to decompose the nitrate, the temperature is maintained at 800 ° C. for 10 hours, and the citric acid and ethylene glycol are burned and removed, so that it is expressed as La _0.7 Ba _0.1 AlO ₃ . A catalyst carrier 1 was obtained.

[Preparation of catalyst carrier 2]
_{La (NO 3) 3 · 6H} 2 O 7.63g, Ba (NO 3) 2 1.97g, Al (NO 3) 3 · 9H 2 O 9.45g, 31.76g citric acid, ethylene glycol 9.38g and 200 g of pure water was mixed and stirred well, and then heated to remove moisture. Next, after maintaining the temperature at 400 ° C. for 2 hours to decompose the nitrate, the temperature is maintained at 800 ° C. for 10 hours, and the citric acid and ethylene glycol are burned and removed, so that it is expressed as La _0.7 Ba _0.3 AlO ₃ . A catalyst carrier 2 was obtained.

[Preparation of catalyst carrier 3]
_{La (NO 3) 3 · 6H} 2 O 7.63g, Sr (NO 3) 2 1.60g, Al (NO 3) 3 · 9H 2 O 9.45g, 31.76g citric acid, ethylene glycol 9.38g and 200 g of pure water was mixed and stirred well, and then heated to remove moisture. Next, after maintaining the temperature at 400 ° C. for 2 hours to decompose the nitrate, the temperature is maintained at 800 ° C. for 10 hours, and the citric acid and ethylene glycol are burned and removed, so that it is expressed as La _0.7 Sr _0.3 AlO ₃ . A catalyst carrier 3 was obtained.

[Preparation of catalyst carrier 4]
_{La (NO 3) 3 · 6H} 2 O 7.63g, Ca (NO 3) 2 1.24g, Al (NO 3) 3 · 9H 2 O 9,45g, 31.76g citric acid, ethylene glycol 9.38g and 200 g of pure water was mixed and stirred well, and then heated to remove moisture. Next, after maintaining nitrate at 400 ° C. for 2 hours to decompose the nitrate, it was held at 800 ° C. for 10 hours, and the citric acid and ethylene glycol were burned and removed, so that it was expressed as La _0.7 Ca _0.3 AlO ₃ . A catalyst carrier 4 was obtained.

[Preparation of catalyst carrier 5]
_{La (NO 3) 3 · 6H} 2 O 10.91g, thoroughly stirred and mixed _{Al (NO 3) 3 · 9H} 2 O 9.45g, 31.76g citric acid, ethylene glycol 9.38g and pure water 200g Then, the water was removed by heating. Next, after maintaining at 400 ° C. for 2 hours to decompose nitrate, the catalyst carrier 5 represented by LaAlO ₃ was obtained by burning at 10 ° C. for 10 hours to remove citric acid and ethylene glycol. .

Example 1
[Preparation of catalyst A]
The catalyst carrier 1 was impregnated with an aqueous Ni (NO ₃ ) ₂ solution so that the Ni content relative to the total amount of the catalyst was 5% by mass, and the water was evaporated. Next, it was dried at 120 ° C. for 10 hours and calcined at 800 ° C. for 1 hour under air flow. The obtained calcined catalyst was pressure-molded and then pulverized and sieved to obtain a granular catalyst A having an average particle diameter of about 1 to 2 mm.

(Example 2)
[Preparation of catalyst B]
A granular catalyst B having an average particle diameter of about 1 to 2 mm was obtained in the same manner as in Example 1 except that the catalyst carrier 2 was used.

(Example 3)
[Preparation of catalyst C]
The catalyst B was subjected to reduction treatment at 450 ° C. for 1 hour under a hydrogen flow to obtain a catalyst C.

Example 4
[Preparation of catalyst D]
The catalyst B was subjected to reduction treatment at 800 ° C. for 1 hour under a hydrogen flow to obtain a catalyst D.

(Comparative Example 1)
[Preparation of catalyst E]
A granular catalyst E having an average particle diameter of about 1 to 2 mm was obtained in the same manner as in Example 1 except that the catalyst carrier 3 was used.

(Comparative Example 2)
[Preparation of catalyst F]
A granular catalyst F having an average particle diameter of about 1 to 2 mm was obtained in the same manner as in Example 1 except that the catalyst carrier 4 was used.

(Comparative Example 3)
[Preparation of catalyst G]
A granular catalyst G having an average particle diameter of about 1 to 2 mm was obtained in the same manner as in Example 1 except that the catalyst carrier 5 was used.

(Reference Example 1)
[Preparation of catalyst H]
A catalyst H was obtained in the same manner as in Example 4 except that the catalyst E was used.

(Reference Example 2)
[Preparation of catalyst I]
A catalyst I was obtained in the same manner as in Example 4 except that the catalyst F was used.

(Reference Example 3)
[Preparation of catalyst J]
A catalyst J was obtained in the same manner as in Example 4 except that the catalyst G was used.

(Reference Example 4)
[Preparation of catalyst K]
The catalyst carrier 3 was impregnated with an aqueous Ni (NO ₃ ) ₂ solution so that the Ni content relative to the total amount of the catalyst was 5% by mass, and the water was evaporated. Next, it was dried at 120 ° C. for 10 hours and calcined at 800 ° C. for 1 hour under air flow. Subsequently, the Ni-supported carrier was impregnated with an aqueous solution of H ₂ [Cl ₆ Pt] · 6H ₂ O so that the Pt content with respect to the total amount of the catalyst was 0.85% by mass to evaporate water. Next, it was dried at 120 ° C. for 3 hours and calcined at 800 ° C. for 1 hour under air flow. The calcined catalyst was pressure-molded and then pulverized and sieved to obtain a granular catalyst K having an average particle diameter of about 1 to 2 mm.

<Steam reforming reaction>
Using the catalyst A obtained in Example 1, a steam reforming reaction (steam reforming reaction) was performed by the following method, and the steam activity and catalyst life of the catalyst A were evaluated.
First, after desulfurizing the raw material toluene, the obtained desulfurized toluene and water were sufficiently mixed and then vaporized to obtain a reformed raw material. The obtained reforming raw material was introduced into a reformer filled with catalyst A, and a steam reforming reaction was performed under the following reaction conditions.
[Reaction conditions]
Catalyst amount W: 25 mg
W / F: 3.4 gh / mol (W is the catalyst amount (g), and F is the feed rate (mol / h).)
Reaction temperature: 600 ° C
Steam / carbon ratio (molar ratio): 2.0

  When the supply time of the reforming raw material becomes 10 minutes, 55 minutes, 160 minutes, and 180 minutes, the reformed gas obtained by the reforming reaction is sampled and gas chromatography (product name: GC-14B, ( Quantitative analysis of the reformed gas was performed by Shimadzu Corporation)). The time when the reforming material was introduced into the reformer was defined as the supply start time (0 minutes).

The water vapor activity and catalyst life of catalyst A were evaluated by the toluene conversion defined by the following formula. Table 1 shows the toluene conversion rate of catalyst A at each sampling time.
Toluene conversion = (CO in the product gas, CO2, carbon number of moles of CH ₄₎ / (carbon number of moles of toluene) × 100 (%)

  In the same manner as in Example 1, the steam reforming reaction of the catalyst B obtained in Example 2 was performed. Table 1 shows the toluene conversion rate of catalyst B at each sampling time.

  A steam reforming reaction of the catalyst C obtained in Example 3 was performed in the same manner as in Example 1. Table 1 shows the toluene conversion rate of catalyst C at each sampling time.

  A steam reforming reaction using the catalyst D obtained in Example 4 was performed in the same manner as in Example 1 except that the sampling time was set to 10 minutes, 55 minutes, and 160 minutes. Table 1 shows the toluene conversion rate of catalyst D at each sampling time.

  A steam reforming reaction using the catalyst E obtained in Comparative Example 1 was performed in the same manner as in Example 1 except that the sampling time was 10 minutes and 180 minutes. Table 2 shows the toluene conversion rate of catalyst E at each sampling time.

  A steam reforming reaction using the catalyst F obtained in Comparative Example 2 was performed in the same manner as in Example 1 except that the sampling time was 10 minutes and 55 minutes. Table 2 shows the toluene conversion rate of catalyst F at each sampling time.

  A steam reforming reaction using the catalyst G obtained in Comparative Example 3 was performed in the same manner as in Example 1 except that the sampling time was 10 minutes and 55 minutes. Table 2 shows the toluene conversion rate of the catalyst G at each sampling time.

  A steam reforming reaction using the catalyst H obtained in Reference Example 1 was performed in the same manner as in Example 1 except that the sampling time was set to 10 minutes, 55 minutes, and 180 minutes. Table 3 shows the toluene conversion rate of catalyst H at each sampling time.

  A steam reforming reaction using the catalyst I obtained in Reference Example 2 was performed in the same manner as in Example 1 except that the sampling time was set to 10 minutes, 55 minutes, and 180 minutes. Table 3 shows the toluene conversion rate of catalyst I at each sampling time.

  A steam reforming reaction using the catalyst J obtained in Reference Example 3 was performed in the same manner as in Example 1 except that the sampling time was set to 10 minutes, 55 minutes, and 180 minutes. Table 3 shows the toluene conversion rate of catalyst J at each sampling time.

  A steam reforming reaction using the catalyst K obtained in Reference Example 4 was performed in the same manner as in Example 1 except that the sampling time was set to 10 minutes, 55 minutes, and 180 minutes. Table 3 shows the toluene conversion rate of the catalyst K at each sampling time.

<Analysis by powder X-ray diffraction (XRD)>
The catalyst carrier 2 was analyzed under the following conditions using RINT2500 (radiation source: CuKα, using a monochromator, voltage 50 KV, power supply 200 mA) manufactured by Rigaku as an XRD apparatus.
Measurement method: Concentration method (continuous)
Divergent slit: 1/2 deg
Divergence length restriction slit: 10 mm
Scattering slit: 1/2 deg
Light emitting slit: 0.15mm
Offset angle: 0deg
Scan speed: 2 deg / min
Sampling width: 0.02 deg
2θ: 5 to 90 deg

  The X-ray diffraction pattern of the catalyst carrier 2 is shown in FIG. The X-ray diffraction pattern of the catalyst support 2 shows the maximum diffraction peak at 2θ = 33.4 °.

  DESCRIPTION OF SYMBOLS 1 ... Water tank, 2 ... Water pump, 3 ... Fuel tank, 4 ... Fuel pump, 5 ... Desulfurizer, 6 ... Vaporizer, 7 ... Reformer, 8 ... Air blower, 9 ... Shift reactor, 10 ... One Carbon oxide selective oxidation reactor, 11 ... anode, 12 ... cathode, 13 ... solid polymer electrolyte, 14 ... electric load, 15 ... exhaust port, 16 ... fuel cell, 17 ... burner, 20 ... supply section.

Claims (4)

The catalyst for hydrogen production containing the support | carrier containing the oxide represented by the following compositional formula (I), and nickel.
La _1-x Ba _x AlO ₃ (where 0.05 ≦ x ≦ 0.5) (I)   The catalyst for hydrogen production according to claim 1, wherein the oxide exhibits a maximum diffraction peak in a range of 2θ of 33 ° to 34 ° in a powder X-ray diffraction spectrum of the oxide. Asked to the hydrogen production catalyst was analyzed by ICP emission spectrometry to moles _{n Ni} nickel, the ratio _n Ba _{/ n Ni} molar number _{n Ba} barium is 0.01 to 20, The hydrogen production catalyst according to claim 1 or 2. A reforming section for reforming a reforming raw material containing hydrocarbon compounds into a reformed gas containing hydrogen,
The fuel cell system in which the said reforming part contains the catalyst for hydrogen production as described in any one of Claims 1-3.

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