JP2003103171A - Catalyst and method for auto thermal reforming, hydrogen producing device and fuel cell system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a catalyst for auto thermal reforming (ATR) which is excellent in stability, an ATR method and a hydrogen producing device which enables performance of the reaction stably for long time and a fuel cell system which is excellent in stability. SOLUTION: This catalyst for ATR is made by depositing at least one kind of group VIII metals selected from iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium and platinum on a solid super-strong acid carrier. This ATR method uses the catalyst. This hydrogen producing device has the ATR device provided with the catalyst. This fuel cell system has the hydrogen producing device and the fuel cell.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a catalyst for converting hydrocarbons into a mixed gas containing carbon monoxide and hydrogen by an autothermal reforming reaction and a method thereof. The present invention also relates to a hydrogen production apparatus that produces a gas containing hydrogen by autothermal reforming, and a fuel cell system including such a hydrogen production apparatus.

[0002]

2. Description of the Related Art Steam reforming (SR) and auto thermal reforming (AT) are used as techniques for reforming organic compounds such as hydrocarbons and converting them into synthesis gas and hydrogen.
Various methods such as R) and partial oxidation (POX) have been developed.

Of these, many technologies have already been put to practical use for SR, but since it is a reaction involving a relatively large endotherm,
It is inferior in that the load on the heat supply system such as a heat exchanger is large and it takes time to start.

On the other hand, contrary to SR, POX has a very short start-up time, but it is difficult to control because of large heat generation due to oxidation, and there are problems such as suppression of soot generation.

On the other hand, ATR is a method of balancing reaction heat by advancing SR by heat generated at this time while oxidizing a part of fuel, and the startup time is relatively short and control is easy. Therefore, it has recently attracted attention as a hydrogen production method for fuel cells.

ATR is usually carried out in the presence of a suitable catalyst. Heretofore, as catalysts for ATR, for example, JP-A-2000-84410 and JP-A-2001-8090 are available.
No. 7, gazette, "2000 Annual Progress"
s Reports (Office of Trans)
portation Technologies) ",
As described in US Pat. No. 5,929,286, it is known that nickel and precious metals such as platinum, rhodium and ruthenium have an activity. Of these, nickel and ruthenium have attracted attention because both elements are relatively inexpensive and highly active. However, for nickel catalysts, a steam / carbon ratio is generally set to suppress coking when applied to the SR reaction. Since it has to be set high, the ATR also has a drawback that a high steam / carbon ratio is required to obtain a long catalyst life. On the other hand, although the ruthenium catalyst is unlikely to cause the problem of coking, there remains a problem that the life stability cannot be secured at a high temperature in the presence of oxygen.

[0007]

The object of the present invention is to provide a catalyst for ATR which is excellent in long-term stability.
Another object of the present invention is to provide an ATR method and a hydrogen production apparatus capable of producing hydrogen by performing a reforming reaction stably for a long period of time. Moreover, it aims at providing the outstanding fuel cell system which has such an outstanding hydrogen production apparatus.

[0008]

Means for Solving the Problems The present inventors have earnestly studied a method for producing a mixed gas containing carbon monoxide and hydrogen by ATR, and as a result, have found that a metal-supported catalyst using a solid superacid is used as a carrier. Thus, the inventors have found a technique capable of providing a reaction system excellent in long-term stability in ATR, and completed the present invention.

That is, according to the present invention, iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium,
It is a catalyst for autothermal reforming in which at least one kind of Group VIII metal selected from the group consisting of iridium and platinum is supported on a solid superacid carrier.

It is preferable that the solid superacid carrier comprises a zirconium oxide or hydroxide carrying sulfur oxide or tungsten oxide.

It is also preferred that the Group VIII metal is ruthenium.

The present invention also relates to an autothermal reforming method for reforming hydrocarbon compounds in the presence of oxygen, water vapor and a catalyst to produce a gas composition containing carbon monoxide and hydrogen. An autothermal reforming method is characterized by using the catalyst of the present invention.

The present invention is also a hydrogen production apparatus having an autothermal reforming apparatus equipped with the above catalyst.

The hydrogen producing apparatus may further have a carbon monoxide selective removing means for selectively removing carbon monoxide from the gas composition containing carbon monoxide and hydrogen produced by the autothermal reforming apparatus. it can.

The present invention also includes a fuel cell system including the above hydrogen producing apparatus and a fuel cell using the hydrogen produced by the hydrogen producing apparatus as a fuel.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Autothermal reforming (ATR) in the present invention is a reaction for converting a hydrocarbon compound into a reforming gas containing carbon monoxide and hydrogen in the presence of oxygen, steam and a catalyst. Say. This reaction includes an oxidation reaction that oxidizes a part of the hydrocarbon compounds and a steam reforming reaction.

Hydrocarbon compounds which can be preferably used as a raw material (object to be reformed by ATR) are:
An organic compound having a basic skeleton having 1 to 25 carbon atoms, and more preferably having a basic skeleton having 1 to 15 carbon atoms. Specific examples thereof include saturated aliphatic hydrocarbons, unsaturated aliphatic hydrocarbons, aromatic hydrocarbons, and the like. For saturated aliphatic hydrocarbons and unsaturated aliphatic hydrocarbons, chain-like or cyclic Can be used regardless. Aromatic hydrocarbons are also monocyclic,
It can be used regardless of polycycle. Such hydrocarbon compounds can contain substituents. As the substituent, a chain,
Both cyclic groups can be used, and examples thereof include an alkyl group, a cycloalkyl group, an aryl group, an alkaryl group and an aralkyl group. The hydrocarbon compounds and the substituents of the hydrocarbon compounds may further include one or more non-hydrocarbon substituents having one or more heteroatoms such as oxygen, nitrogen, halogen and sulfur. Examples of the non-hydrocarbon substituent include a halogen atom (-F, -C).
1, -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. Substituents are not limited to these, and those that poison the catalyst, or those that induce undesirable side reactions or by-products, and hydrocarbon compounds having such substituents are appropriately removed or treated. Can be used.

Specific examples of hydrocarbon compounds include methane, ethane, propane, butane, pentane, hexane,
Examples thereof include saturated aliphatic hydrocarbons such as cyclopentane, cyclohexane and dodecane, unsaturated aliphatic hydrocarbons such as ethylene, propylene and butene, and aromatic hydrocarbons such as benzene, toluene, xylene and naphthalene. Further, a mixture of these can also be preferably used, and examples thereof include materials that are industrially inexpensively available, such as natural gas, LPG, naphtha, gasoline, kerosene, and light oil. Specific examples of the hydrocarbon compound having a substituent containing a hetero atom include methanol, ethanol, propanol, butanol, dimethyl ether, phenol, anisole, acetaldehyde, acetic acid and the like. Further, a raw material containing hydrogen, water, carbon dioxide, carbon monoxide, oxygen or the like can be used as the above raw material. For example, when performing hydrodesulfurization as a pretreatment of the raw material,
The residual hydrogen used in the reaction can be mixed with the raw material without any particular separation.

On the other hand, the sulfur concentration in the raw material is desirably as low as possible because it has the effect of inactivating the reforming catalyst, and is preferably 50 mass ppm or less, more preferably 20 mass ppm or less. Therefore, if necessary, the raw material can be desulfurized in advance.

The sulfur concentration in the raw material to be subjected to the desulfurization step is not particularly limited, and any raw material having a sulfur concentration that can be converted to the above sulfur concentration in the desulfurization step can be used.

The desulfurization method is also not particularly limited, but a method in which hydrodesulfurization is carried out in the presence of a suitable catalyst and hydrogen and the produced hydrogen sulfide is absorbed in zinc oxide or the like can be given as an example. In this case, examples of catalysts that can be used include catalysts containing nickel-molybdenum, cobalt-molybdenum, or the like. On the other hand, if necessary, a method of sorbing a sulfur content in the presence of hydrogen in the presence of an appropriate sorbent can also be adopted. As sorbents that can be used in this case, Japanese Patent Nos. 2654515 and 26
Examples thereof include a sorbent containing copper-zinc as a main component or a sorbent containing nickel-zinc as a main component as disclosed in Japanese Patent No. 88749.

The method for carrying out the desulfurization step is not particularly limited, either.
It may be carried out by a desulfurization process installed immediately before the autothermal reforming reactor according to the present invention, or a raw material treated in an independent desulfurization process may be used.

Oxygen is usually added to the reaction raw material to the extent that it can generate a heat quantity that can balance the endothermic reaction of SR, but the addition quantity is appropriately determined in relation to heat loss and external heating installed as necessary. . The amount is preferably 0.05 as a ratio of the number of moles of oxygen molecules supplied to the ATR reaction region to the number of moles of carbon atoms contained in the raw material hydrocarbon compounds supplied to the ATR reaction region (oxygen / carbon ratio).
˜1, more preferably 0.1 to 0.75, and still more preferably 0.2 to 0.6. When the oxygen / carbon ratio is smaller than the above range, a small amount of heat is generated and a large amount of heat needs to be supplied from the outside, which is disadvantageous in that the situation is substantially the same as SR. On the other hand, oxygen /
When the carbon ratio is larger than the above range, heat generation becomes large and it is difficult to balance the heat, and it is disadvantageous in that hydrogen and carbon monoxide are burned and consumed by oxygen and the modified gas yield is reduced.

The oxygen may be pure oxygen, but those diluted with other gas can be preferably used, such as water vapor,
It may contain carbon dioxide, carbon monoxide, argon, nitrogen, etc. For example, from the viewpoint of easy availability, air is preferably used as the gas containing oxygen.

The method of adding oxygen to the raw material is not particularly limited, but it may be introduced into the reaction region at the same time as the raw material hydrocarbon compound, or the oxygen-containing gas and the hydrocarbon compound may be introduced from different positions in the reaction region. The oxygen-containing gas may be supplied, or the oxygen-containing gas may be divided into several portions and introduced partially.

The amount of steam introduced into the reaction system is ATR
It is defined as the ratio of the number of moles of water molecules supplied to the ATR reaction zone to the number of moles of carbon atoms contained in the raw material hydrocarbon compounds supplied to the reaction zone (steam / carbon ratio), and this value is preferably 0.3. -10, more preferably 0.5-5, still more preferably 1-3. If this value is smaller than the above range, coke tends to precipitate on the catalyst, and the hydrogen content obtained tends to decrease, while it is disadvantageous if the value is larger. However, it is disadvantageous in that it may lead to enlargement of steam generation equipment and steam recovery equipment.

The method of adding steam to the hydrocarbon compound is not particularly limited, but it may be introduced into the reaction region at the same time as the starting hydrocarbon compound, or it may be introduced from different positions in the reaction region or divided into several times. You may introduce them part by part.

Carbon dioxide may be added to the raw material gas for the purpose of mainly obtaining carbon monoxide. The amount of carbon dioxide added in this case is
It is defined as a ratio (carbon dioxide / carbon ratio) of the number of moles of carbon dioxide molecules supplied to the ATR reaction region to the number of moles of carbon atoms (excluding carbon dioxide content) contained in the raw material hydrocarbons supplied to the reaction region, Its value is preferably in the range of 0.1 to 5, more preferably 0.1 to 3.
However, the addition of carbon dioxide is not always necessary, especially for the purpose of producing hydrogen.

Solid superacid means the Hammett acidity function (H ₀ ) <-11.93 ("Superacid / superbase" by Kozo Tabe and Ryoji Noyori, Kodansha Scientific <19.
80>), which is a solid acid having a stronger acid strength than 100% sulfuric acid, and those corresponding to this definition can be widely used. As an example, there may be mentioned those in which a hydroxide or oxide of titanium, zirconium, hafnium, iron, aluminum, tin or the like is used as a carrier and sulfur oxide or tungsten oxide is supported.

The preparation method of these solid superacids is, for example,
It can be carried out by supporting a precursor of sulfur oxide or tungsten oxide on the carrier as described above and then firing. Examples of sulfur oxide precursors include sulfuric acid, ammonium sulfate, sulfuryl chloride, thionyl chloride, SO ₂ gas, and the like, and examples of tungsten oxide precursors include ammonium metatungstate, ammonium paratungstate, 12 tungstophosphoric acid etc. can be mentioned.

As a method of loading, a known appropriate method can be adopted, but a method of dissolving in a suitable solvent such as water, suspending the carrier and drying the solvent can be employed. When using a precursor that easily reacts with water, such as sulfuryl chloride or thionyl chloride, it is desirable to use a solvent such as hexane or methylene chloride.

As a method of expressing super-strong acidity, it is generally adopted to calcine the carrier carrying the precursor thus obtained. The firing temperature for this purpose is appropriately selected depending on the combination of the carrier and the sulfur oxide precursor or the tungsten oxide precursor. If a specific example is given, in the case of the combination of sulfur oxide-zirconium oxide, it is preferably in the range of 500 ° C. to 800 ° C., more preferably 600 ° C. to 700 ° C. In this case, preferably 700 ° C to 1000 ° C, more preferably 800 ° C to 9 ° C.
It is in the range of 00 ° C. However, it is only necessary that a substance corresponding to the above definition of the super strong acid can be obtained after firing, and the conditions are not limited to these. Confirmation of being a super strong acid can be performed by, for example, “J. Chem. Soc. Chem. Commun. 1259 (198
9) ”,“ J. Chem. Soc. Chem. Commun. 1148 (1
979), J. Chem. Soc. Chem. Commun. 1851 (1
980) "," J. Am. Chem. Soc. 101, 6439.
(1979) ”and the like, and skeleton isomerization of paraffin and acid strength measurement can be performed.

In the present invention, the above-mentioned catalyst in which a metal which is active for autothermal reforming is supported on the solid superacid is used. At this time, the active metal is a Group VIII metal selected from the group consisting of iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium, and platinum, and the catalyst containing the active metal is any of these. A catalyst containing ruthenium is preferably used from the viewpoints of containing one or more metal species, having a relatively low price, high activity, and less likely to cause coking. The Group VIII metal may have any valency, and may be in a zero-valent state or in a valence other than that, for example, in the form of a compound such as an oxide.

There is no particular limitation on the method for preparing the solid superacid catalyst carrying the above-mentioned active metal (hereinafter referred to as the catalyst of the present invention). Prepare a strong acid carrier,
Any known method such as a method of subsequently supporting an active metal or a method of first supporting an active metal and a sulfur oxide or a tungsten oxide and then developing solid superacidity by firing is applicable.

The method for supporting the active metal in the catalyst of the present invention is also not particularly limited, and a known method such as an ordinary impregnation method, an adsorption method or an ion exchange method can be adopted. For example, when the impregnation method is used, it is usually dissolved as a salt or complex of an active metal in a solvent such as water, ethanol, or acetone to impregnate a carrier. After that, a supported catalyst can be obtained by performing drying, calcination and the like. The drying condition is not particularly limited, but is, for example, 5
It can be carried out at 0 to 200 ° C. for 1 to 20 hours. The firing conditions are not particularly limited, but may be, for example, 500 to 100 in an air stream or a hydrogen stream.
It can be carried out at 0 ° C. for 1 to 10 hours. Examples of the metal salt or metal complex to be supported include various chlorides, nitrates, organic acid salts and the like, and specifically, iron nitrate, cobalt nitrate, nickel nitrate, ruthenium chloride, ruthenium acetylacetonate, rhodium chloride, palladium chloride. Compounds such as, but not limited to, osmium chloride, iridium chloride, chloroplatinic acid.

The content of the active metal (in the case of a metal compound, the metal content of the compound) in the catalyst of the present invention (when there are a plurality of active metals, the total amount thereof) is preferably 0.
05 to 20% by mass, more preferably 0.1 to 10% by mass, and further preferably 0.3 to 5% by mass can be used. If the content is more than this range, it is disadvantageous in that the active metal aggregates more and the proportion of the metal that appears on the surface decreases, and if it is less than this range, it becomes difficult to exhibit high activity, and thus a large amount of It is disadvantageous in that the catalyst of the present invention is required and the reactor tends to be large.

The metal-supported catalyst thus obtained is activated by reduction treatment with hydrogen or the like if necessary.

In the ATR using the catalyst of the present invention, which was surprising to the present inventors, there is a tendency that a large amount of carbon monoxide is produced as compared with the equilibrium composition. When producing a raw material for the production of methanol, synthetic gas oil or synthetic gasoline using the catalyst of the present invention, or when producing a fuel for a solid oxide fuel cell or a fuel for a molten carbonate fuel cell, monoxide is used. Although there is no particular problem that there is a large amount of carbon, when producing hydrogen gas used for phosphoric acid fuel cells, polymer electrolyte fuel cells, etc., it is more preferable to increase the hydrogen content and bring it closer to the equilibrium composition. . For this purpose, ATR
After that, the composition of the mixed gas can be brought close to the equilibrium composition by carrying out a water gas reaction using a catalyst having a water gas reaction activity for converting CO and water into hydrogen and carbon dioxide (hereinafter referred to as a shift catalyst). Is. For this purpose, for example, the former stage of the catalyst layer can be formed with the catalyst of the present invention, and the latter stage can be formed with the shift catalyst.

In the case where the shift catalyst is arranged in the latter stage, the volume ratio of the catalyst of the present invention arranged in the former stage to the shift catalyst arranged in the latter stage is 97: 3 by volume from the viewpoint of the balance between the ATR and the water gas reaction. 50:50, preferably 95: 5 to 50:50, more preferably 90:10.
˜50: 50.

At this time, the shift catalyst is 200 to 10
It is preferable to have water gas reaction activity in the range of 00 ° C., more preferably 300 to 900 ° C., and further preferably 500 to 800 ° C., for example, iron, cobalt,
Nickel, ruthenium, rhodium, palladium, osmium, iridium, platinum (group VIII metal), copper,
Examples thereof include a catalyst containing one or more of silver and gold (Group IB metal). When the catalyst is installed immediately after the autothermal reforming step, it is preferable that it be stable at high temperature.

As the shift catalyst, at least one selected from the group consisting of iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium and platinum (Group VIII metal) and copper, silver and gold (Group IB metal). A catalyst containing one kind can be used, and ruthenium black, rhodium black, palladium black, osmium black, iridium black, platinum black, or a metal simple substance such as each metal foil can be used, but the metal surface area is widened and reaction conditions are increased. In order to ensure the stability in the above, it can be usually used in the form of being supported on a suitable carrier.

In this case, usable carriers include alkali metal oxides such as lithium, sodium, potassium and cesium, alkaline earth metal oxides such as magnesium, calcium, strontium and barium, lanthanum, cerium and praseodymium. Oxides of rare earth metals such as neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium; unitary oxides such as yttrium, titanium, zirconium, hafnium, aluminum, and silicon. It can be illustrated.
Further, a mixed oxide obtained by mixing two or more kinds of these oxides at an arbitrary ratio can be used, and among them, magnesium-titanium, calcium-titanium, strontium-titanium, barium-titanium, magnesium-zirconium, calcium-zirconium. , Strontium-zirconium, barium-zirconium, magnesium-aluminum, calcium-aluminum, strontium-aluminum, barium-aluminum, yttrium-aluminum, titanium-aluminum, zirconium-aluminum, cerium-aluminum, magnesium-silicon, calcium-silicon, strontium. -Silicon, barium-silicon, yttrium-silicon, titanium-silicon, zirconium-silicon, hafnium-silicon, aluminum-silicon, magnet Binary oxides such as um-cerium, calcium-cerium, strontium-cerium, barium-cerium, and magnesium-calcium-titanium, magnesium-barium-titanium, magnesium-yttrium-titanium, magnesium-zirconium-titanium, magnesium- Cerium-titanium, calcium-barium-titanium, calcium-yttrium-titanium, calcium-zirconium-titanium, calcium-cerium-titanium, barium-yttrium-
Titanium, magnesium-calcium-zirconium, magnesium-barium-zirconium, magnesium-
Yttrium-zirconium, magnesium-cerium-zirconium, calcium-barium-zirconium, calcium-yttrium-zirconium, calcium-cerium-zirconium, barium-yttrium-zirconium, barium-titanium-zirconium,
Magnesium-calcium-aluminum, magnesium-barium-aluminum, magnesium-yttrium-aluminum, magnesium-titanium-aluminum, magnesium-zirconium-aluminum, magnesium-cerium-aluminum, calcium-barium-aluminum, calcium-yttrium-aluminum, calcium- Titanium-aluminum, calcium-zirconium-aluminum, calcium-cerium-aluminum, barium-yttrium-aluminum, barium-titanium-aluminum, barium-zirconium-aluminum, barium-cerium-
Aluminum, yttrium-titanium-aluminum,
Yttrium-zirconium-aluminum, titanium-
Zirconium-aluminum, magnesium-calcium-silicon, magnesium-barium-silicon, magnesium-yttrium-silicon, magnesium-titanium-silicon, magnesium-zirconium-silicon, magnesium-cerium-silicon, magnesium-aluminum-silicon, calcium-barium- Silicon, calcium-yttrium-silicon, calcium-titanium-silicon, calcium-zirconium-silicon, calcium-cerium-silicon,
Calcium-aluminum-silicon, barium-yttrium-silicon, barium-titanium-silicon, barium-zirconium-silicon, barium-cerium-silicon, barium-aluminum-silicon, yttrium-titanium-silicon,
Yttrium-zirconium-silicon, yttrium-aluminum-silicon, yttrium-cerium-silicon, titanium-zirconium-silicon, titanium-aluminum-silicon, titanium-cerium-silicon, zirconium-aluminum-silicon, zirconium-cerium-silicon, aluminum- A ternary oxide such as cerium-silicon can be preferably used. Further, oxides obtained by adding alkali metal components such as lithium, sodium, potassium, and cesium to these unitary, binary, and ternary oxides can also be preferably used. In these multi-component oxides, it is not necessary that the respective components are uniformly mixed, and one component may be concentrated on the oxide surface.

The method for preparing such a shift catalyst is not particularly limited, and a known method such as an ordinary impregnation method or a coprecipitation method can be adopted. When the impregnation method is used, it is usually iron nitrate, cobalt nitrate, nickel nitrate, ruthenium chloride, rhodium chloride,
Palladium chloride, osmium chloride, iridium chloride, compounds such as chloroplatinic acid are dissolved in a solvent such as water, ethanol or acetone, impregnated into a carrier, and then dried and fired.
It can be implemented by performing a reduction process.

Iron, cobalt, nickel in the shift catalyst,
Ruthenium, Rhodium, Palladium, Osmium, Iridium, Platinum (Group VIII metal), Copper, Silver, Gold (Group I
The content of the group B metal) (when there are plural kinds of these metals, the total amount thereof) is preferably 0.1 to 20% by mass, more preferably 0.2 to 10% by mass, and further preferably 0.
5 to 5 mass% can be used. If the content is more than this range, it is disadvantageous in that the component tends to agglomerate and the rate at which it appears on the surface tends to decrease, while if it is less than this range, it becomes difficult to exhibit high activity, and therefore a large amount of It is disadvantageous in that a shift catalyst is required and the reactor tends to be large.

There are no particular restrictions on the shape of the catalyst used for both the catalyst of the present invention and the shift catalyst. For example, it is possible to use a catalyst which has been tableted and crushed and then sized to an appropriate range, an extruded catalyst, an extruded catalyst to which an appropriate binder is added, and a powdered catalyst. Alternatively, a carrier which is tableted and crushed and then sized in an appropriate range, an extruded carrier, a powder or a sphere, a ring, a tablet,
It is possible to use a catalyst in which a metal is supported on a carrier or the like which is formed into an appropriate shape such as a cylindrical shape or a flake shape. Also,
It is possible to use a catalyst in which the catalyst itself is formed in a monolith shape, a honeycomb shape, or the like, or a monolith or honeycomb formed of an appropriate material and coated with the catalyst.

The form of the reactor that can be provided in the autothermal reforming device of the hydrogen production device of the present invention will be described. In the present invention, the flow type fixed bed reactor may be configured to include the catalyst of the present invention as a catalyst. The reactor may have any known shape such as a cylindrical shape or a flat plate shape depending on the purpose of each process. It is also possible to use a fluidized bed reactor for the ATR device.

The space velocity of the object to be treated (the object to be treated containing hydrocarbon compounds, water vapor and oxygen supplied to the ATR reaction region) introduced into the reactor is based on the total amount of the catalyst of the present invention and the shift catalyst. As, preferably GHSV is 500
To 1,000,000 h ⁻¹ , more preferably 1,
Range 000~800,000h ^-1, more preferably in the range of 1,500~500,000h ^-1, is set in view of the respective purposes.

Although the reaction temperatures of the ATR and the water gas reaction can be controlled independently of each other, particularly when the catalyst layer of the catalyst of the present invention and the catalyst layer of the shift catalyst are provided adjacent to each other in the former stage and the latter stage, they are integrated. It can also be controlled.
Both the reaction temperature of ATR and the reaction temperature of the water gas reaction are preferably 200 to 1000 ° C., more preferably 300 to 90.
The temperature is 0 ° C, more preferably 500 to 800 ° C.

The reaction pressure for ATR and water gas reactions is
Although not particularly limited, it is preferably atmospheric pressure to 20 MPa,
It is more preferably carried out in the range of atmospheric pressure to 5 MPa, still more preferably atmospheric pressure to 1 MPa.

In the case of a solid oxide fuel cell or a molten carbonate fuel cell, the gas composition containing carbon monoxide and hydrogen (reformed gas) obtained by the present invention is used as it is as the fuel for the fuel cell. Can be used as In addition, when it is necessary to remove carbon monoxide as in a phosphoric acid fuel cell or a polymer electrolyte fuel cell, it can be preferably used as a raw material for producing hydrogen for the fuel cell.

For removing carbon monoxide, a known method for selectively removing carbon monoxide can be adopted. Examples of the carbon monoxide selective removal method 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, which contains a mixed oxide of Fe--Cr, a mixed oxide of Zu--Cu, platinum, ruthenium, iridium and the like. The catalyst is used to reduce the carbon monoxide content on a dry basis to preferably 2% by volume or less, more preferably 1% by volume or less, and further preferably 0.5% by volume or less. Usually, in a phosphoric acid fuel cell, a mixed gas in this state can be used as a fuel.

On the other hand, in the polymer electrolyte fuel cell, it may be necessary to further reduce the carbon monoxide concentration. In this case, the CO selective oxidation step or the like is performed. In this process, iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium, platinum, copper,
Using a catalyst containing silver, gold or the like, the amount of the remaining carbon monoxide is preferably 0.5 to 10 times, more preferably 0.7 to 5 times, and still more preferably 1 to 3 times. The concentration of carbon monoxide is reduced by selectively converting carbon monoxide into carbon dioxide by adding oxygen. In this case, it is possible to reduce the carbon monoxide concentration by reacting with the coexisting hydrogen and producing methane simultaneously with the oxidation of carbon monoxide.

The hydrogen producing apparatus of the present invention has an ATR apparatus equipped with the catalyst of the present invention. The hydrogen production apparatus of the present invention may further have a carbon monoxide selective removal means for selectively removing carbon monoxide from the gas composition containing carbon monoxide and hydrogen produced by the ATR apparatus. Therefore, the hydrogen production apparatus can be provided with the ATR device of the present invention and a shift reactor or a CO selective oxidation device.

An example of the fuel cell system of the present invention will be described below. FIG. 1 is a schematic diagram showing an example of a fuel cell power generation system of the present invention.

In FIG. 1, the fuel in the fuel tank 3 flows into the desulfurizer 5 via the fuel pump 4. The desulfurizer can be filled with, for example, a copper-zinc-based or nickel-zinc-based sorbent. At this time, if necessary, the hydrogen-containing gas from the selective oxidation reactor 11 can be added. The fuel desulfurized by the desulfurizer 5 is mixed with water from the water tank 1 through the water pump 2 and then introduced into the vaporizer 6 to be vaporized, and then mixed with the air sent from the air blower 8 to the reformer 7. Sent in.

A solid super-strong acid-supported ruthenium catalyst and an alumina-supported ruthenium catalyst are used as the catalyst of the reformer 7, and the fuel mixture (the object to be treated containing hydrocarbon compounds, steam and oxygen) is first converted into the solid super-strong acid-supported ruthenium catalyst. Then, each catalyst is loaded into the reformer so as to contact the alumina-supported ruthenium catalyst.

At this time, the oxygen / carbon ratio is preferably
0.05 to 1, more preferably 0.1 to 0.75, and
Is preferably set to 0.2 to 0.6, and steam / carbon
Carbon ratio is preferably 0.3 to 10, more preferably
It is set to 0.5 to 5, more preferably 1 to 3. Well
Also, the space velocity of the fuel mixture is the total amount of the above two types of catalysts.
GHSV is preferably 50 in terms of standard and standard temperature / pressure conversion
0 to 1,000,000h ^-1, And more preferably 1,00
0-800,000h^-1, More preferably 1,500
~ 500,000h^-1It is set to the range of. At this time, acid
By controlling the element / carbon ratio and space velocity appropriately
The temperature in the reformer is preferably 200 to 1000 ° C,
More preferably 300 to 900 ° C., more preferably 50
Control to 0-800 ° C.

The thus-produced gas containing hydrogen and carbon monoxide is sequentially passed through the high temperature shift reactor 9, the low temperature shift reactor 10 and the selective oxidation reactor 11 so that the concentration of carbon monoxide is reduced in the fuel cell. It is reduced to the extent that it does not affect the characteristics of. Examples of catalysts used in these reactors are an iron-chromium based catalyst for the high temperature shift reactor 9, a copper-zinc based catalyst for the low temperature shift reactor 10, and a selective oxidation reactor 1.
Examples of 1 include ruthenium-based catalysts and the like.

The polymer electrolyte fuel cell 17 has an anode 1
2, a cathode 13, and a solid polymer electrolyte 14, a fuel gas containing the high-purity hydrogen obtained by the above method is required on the anode side, and air sent from an air blower 8 is required on the cathode side. If so, it is introduced after performing an appropriate humidification treatment (a humidifier is not shown).

At this time, a reaction in which hydrogen gas becomes a proton and releases an electron proceeds at the anode, and a reaction in which oxygen gas obtains an electron and a proton and becomes water proceeds at the cathode.
In order to accelerate these reactions, platinum black, Pt catalyst or Pt-Ru alloy catalyst supporting active carbon is used for the anode, and platinum black, Pt catalyst supporting active carbon is used for the cathode, respectively.

Normally, both the anode and cathode catalysts are molded into a porous catalyst layer together with Teflon (registered trademark), a low molecular weight polymer electrolyte membrane material, activated carbon, etc., if necessary.

Next, Nafion (Dupont), Go
re (Gore), Flemion (Asahi Glass), Aci
MEA (Memb) is prepared by laminating the porous catalyst layers on both sides of a polymer electrolyte membrane known by trade names such as Plex (Asahi Kasei).
lane Electrode Assembly: a membrane electrode assembly) is formed. Furthermore, MEA is a metal material,
A fuel cell is assembled by sandwiching it with a separator made of graphite, carbon composite, etc., having a gas supply function, a current collection function, and particularly an important drainage function at the cathode. The electric load 15 is electrically connected to the anode and the cathode.

The anode off-gas is burned in the combustion heat exchanger 18 and used for heating the raw material water, and then the exhaust port 19
Emitted from. The cathode off gas is discharged from the exhaust port 16.

[0065]

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to these examples.

[Catalyst Preparation Example] 0.1M (mol / L) was added to zirconium hydroxide precipitated by adding aqueous ammonia to zirconyl oxychloride so that the supported W amount before firing was 15% by mass. Then, an ammonium metatungstate aqueous solution is added to carry out impregnation. Dry to 1 at 120 ° C
After drying for 2 hours, it is baked at 850 ° C. for 3 hours under air flow to obtain a super strong acid carrier WO _X —ZrO ₂ (X = 3 to 4). This is the carrier 1.

Zirconyl oxychloride is added with aqueous ammonia to impregnate and carry 10 mass times of 1N (normal) sulfuric acid on zirconium hydroxide precipitated. Air dried, 120
After being dried at ℃ for 12 hours, it is calcined at 700 ℃ for 3 hours under air flow to obtain super strong acid carrier SO ₄ ² -ZrO ₂ . This is carrier 2
And

Regarding these carriers, “J. Chem. Soc. Ch.
em. Commun. 1259 (1989), J. Chem. Soc. Ch
em. Commun. 1148 (1979) "," J. Chem. So
c. Chem. Commun. 1851 (1980) "," J. Am.
Chem. Soc. 101, 6439 (1979) ”, a skeletal isomerization test of hexane was carried out. As a result, it was revealed that the hexane had an isomerization reaction activity, and it was confirmed to be a solid superacid.

To the carrier 1, a 0.1 M RuCl ₃ aqueous solution was added so that the amount of supported Ru would be 2% by mass as the amount of metal, impregnated and supported, dried and dried at 120 ° C. for 12 hours, then under a hydrogen stream to 200 Treated at ℃ for 2 hours, then under air flow 70
Treatment is carried out at 0 ° C. for 3 hours to obtain 2% Ru / WO _X -ZrO ₂ . This is designated as catalyst A.

To the carrier 2, a 0.1 M RuCl ₃ aqueous solution was added so that the amount of supported Ru would be 2% by mass as the amount of metal, impregnated and supported, dried and dried at 120 ° C. for 12 hours, then under a hydrogen stream to 200. Treated at ℃ for 2 hours, then under air flow 70
Treatment is performed at 0 ° C. for 3 hours to obtain 2% Ru / SO ₄ ²⁻ —ZrO ₂ . This is designated as catalyst B.

To a commercially available γ-alumina, a 0.1 M RuCl ₃ aqueous solution was added so that the amount of Ru supported was 2% by mass as a metal amount, impregnated and supported, dried and dried at 120 ° C. for 12 hours.
Treated at 700 ° C under hydrogen flow for 3 hours, and 2% Ru / Al
₂ O ₃ is obtained. This is designated as catalyst C.

To zirconium hydroxide precipitated by adding aqueous ammonia to zirconyl oxychloride, a 0.1M RuCl ₃ aqueous solution was added so that the amount of supported Ru would be 2% by mass as a metal amount, impregnated, supported and dried. After being solid and dried at 120 ° C. for 12 hours, it is treated at 700 ° C. for 3 hours in a hydrogen stream to obtain 2% Ru / ZrO ₂ . This is designated as catalyst D.

[Example 1] Catalyst A obtained in the catalyst preparation example
Was tableted, crushed, and then sized, and then sized to a range of 250 to 500 μm, 0.7560 g was packed in a fixed bed flow reactor, and a mixed gas of normaldodecane, steam and oxygen was used as a raw material, and ATR was performed at 650 ° C. The reaction was carried out. The reaction conditions are shown in Table 1.

Example 2 The reaction was performed in the same manner as in Example 1 except that the catalyst B was used in place of the catalyst A.

[Example 3] Catalyst A obtained in the catalyst preparation example
Was tablet-molded, pulverized, and sized, and then sized in the range of 250 to 500 μm, 0.7560 g was packed in a fixed-bed flow reactor, and a mixed gas of normaldodecane, steam and oxygen was used as a raw material, and ATR was performed at 750 ° C. The reaction was carried out.

[Embodiment 4] The catalyst A was added to the upstream side of the catalyst layer in an amount of 0.
The reaction was performed in the same manner as in Example 3 except that 7560 g and 0.189 g of the catalyst C were used in the latter stage.

[Comparative Example 1] The reaction was performed in the same manner as in Example 1 except that the catalyst C was used in place of the catalyst A.

Comparative Example 2 The reaction was carried out in the same manner as in Example 1 except that the catalyst D was used in place of the catalyst A.

[Comparative Example 3] The reaction was performed in the same manner as in Example 3 except that the catalyst C was used in place of the catalyst A.

Example 5 A reaction was carried out in the same manner as in Example 1 except that kerosene was used instead of normal dodecane.

[Comparative Example 4] The reaction was carried out in the same manner as in Comparative Example 1 except that kerosene was used in place of the normal dodecane.

Example 6 A reaction was carried out in the same manner as in Example 1 except that naphtha was used instead of normal dodecane.

[Comparative Example 5] The reaction was carried out in the same manner as in Comparative Example 1 except that naphtha was used instead of the normal dodecane.

Regarding Examples 3 and 4 and Comparative Example 3,
Table 2 shows the composition of the produced gas one hour after the start of the reaction and the equilibrium composition (calculated value) under the same conditions. It should be noted that, 5 hours after the start of the reaction, the composition of the produced gas was the same as that of the composition after 1 hour in Examples 3 and 4 and no catalyst deterioration was observed, but in Comparative Example 3, catalyst deterioration was observed. It was

In Table 2, in both the ruthenium catalyst supporting γ-alumina (Comparative Example 3) and the ruthenium catalyst supporting solid superacid (Example 3), n-dodecane was completely converted, but the produced gas composition was large. different. In the γ-alumina-supported ruthenium catalyst, the composition is almost equal to the equilibrium composition, whereas in the catalyst in which ruthenium is supported on the solid superacid, n-dodecane is completely converted, but the ratio of carbon monoxide is The value is higher than the equilibrium value. Example 4
By arranging a small amount of a γ-alumina-supporting ruthenium catalyst having a CO shift ability in the subsequent stage of the solid superacid-supporting ruthenium catalyst as described above, it is possible to obtain a product gas that substantially matches the equilibrium value.

Table 3 shows the change in conversion rate over time. The conversion rate is given by the following equation.

[0087]

[Equation 1]

As shown in Table 3, in the case of a catalyst having ruthenium supported on an ordinary carrier such as γ-alumina or zirconia, the conversion rate decreases with the passage of time, whereas the solid superacid is used as a carrier and ruthenium is added. The supported catalyst can stably carry out the ATR reaction in the presence of oxygen.

[0089]

[Table 1]

[0090]

[Table 2]

[0091]

[Table 3]

[Embodiment 7] In the fuel cell system having the structure shown in FIG. 1, a test was conducted using kerosene as a fuel. At this time, the oxygen / carbon ratio of the raw material introduced into the reformer 7 was set to 0.4, and the steam / carbon ratio was set to 2.0. As a result of analysis of the gas at the anode inlet, hydrogen was contained in an amount of 42% by volume (excluding steam).

During the test period (10 hours), the reformer operated normally and no reduction in the activity of the catalyst was observed. The fuel cell also operated normally, and the electric load 15 also operated smoothly.

[0094]

According to the present invention, when hydrocarbons are converted into a mixed gas containing carbon monoxide and hydrogen by ATR, the oxidation stability, which has heretofore been difficult to achieve by ruthenium, is improved. It is possible to provide a stable catalyst. Such a gas can be suitably used as a fuel for a fuel cell or a raw material thereof. Further, a method and a hydrogen production apparatus capable of stably producing a mixed gas containing carbon monoxide and hydrogen are provided. Furthermore, a fuel cell system having an excellent hydrogen production device and excellent stability was provided.

[Brief description of drawings]

FIG. 1 is a flow chart showing an example of a fuel cell system of the present invention.

[Explanation of symbols]

1 water tank 2 water pump 3 fuel tank 4 fuel pump 5 desulfurizer 6 vaporizer 7 reformer 8 air blowers 9 High temperature shift reactor 10 Low temperature shift reactor 11 Selective oxidation reactor 12 Anode 13 cathode 14 Solid polymer electrolyte 15 Electric load 16 exhaust port 17 Polymer electrolyte fuel cell 18 Combustion heat exchanger 19 exhaust port

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) // H01M 8/10 B01J 23/64 103M F term (reference) 4G040 EA02 EA03 EA06 EA07 EB31 EB32 EC02 EC03 4G069 AA03 BA05A BA46A BB02A BB04A BB05A BB06A BB06B BB10A BB10B BC51A BC51B BC60A BC60B BC66A BC67A BC68A BC69A BC70A BC70B BC71A BC72A BC73A BC74A BCEEA 5EE12A0 5EE02 A11 5H0626A05 5H0626A05 5H026A05

Claims (7)

[Claims] 1. For autothermal reforming in which at least one Group VIII metal selected from the group consisting of iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium and platinum is carried on a solid superacid carrier. catalyst. 2. The catalyst for autothermal reforming according to claim 1, wherein the solid superacid carrier is a zirconium oxide or hydroxide carrying sulfur oxide or tungsten oxide. 3. The autothermal reforming catalyst according to claim 1, wherein the Group VIII metal is ruthenium. 4. The autothermal reforming method for reforming hydrocarbon compounds in the presence of oxygen, steam and a catalyst to produce a gas composition containing carbon monoxide and hydrogen, wherein the catalyst is used as the catalyst. An autothermal reforming method, characterized by using the catalyst according to any one of items 1 to 3. 5. A hydrogen production apparatus comprising an auto-thermal reforming apparatus equipped with the catalyst according to claim 1. 6. The hydrogen according to claim 5, further comprising a carbon monoxide selective removal means for selectively removing carbon monoxide from the gas composition containing carbon monoxide and hydrogen produced by the autothermal reforming apparatus. Manufacturing equipment. 7. A fuel cell system comprising: the hydrogen production apparatus according to claim 5; and a fuel cell using hydrogen produced by the hydrogen production apparatus as a fuel.