JP2001270705A - Method for steam reforming of hydrocarbon - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an industrially advantageous method for the steam reforming of hydrocarbon by the use of a catalyst capable of decreasing the deposition of carbon at a low steam/carbon ratio and having high activity and long-life comparable to those of the single use of a noble metal catalyst. SOLUTION: A hydrocarbon is reformed by a steam-reforming method comprising the supply of the hydrocarbon and steam to a catalyst layer. The catalyst layer is at least composed of an upstream catalyst layer composed of a heat-resistant ceramic material and a downstream catalyst layer containing at least one component selected from among ruthenium component, rhodium component and nickel component.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for steam reforming hydrocarbons, and more particularly to a method for efficiently improving the steam reforming activity of hydrocarbons.

[0002]

2. Description of the Related Art In recent years, new energy technologies have been spotlighted due to environmental problems, and fuel cells have attracted attention as one of the new energy technologies. This fuel cell converts chemical energy into electric energy by electrochemically reacting hydrogen and oxygen, and has the feature of high energy use efficiency.
Practical research is being actively conducted for industrial or automotive use. As the fuel cell, types such as a phosphoric acid type, a molten carbonate type, a solid oxide type, and a solid polymer type are known according to the type of electrolyte used. on the other hand,
As a hydrogen source, liquefied natural gas mainly composed of methanol and methane, city gas mainly composed of natural gas, synthetic liquid fuel composed of natural gas as raw material, and petroleum LP
The use of petroleum hydrocarbon oils such as G, naphtha, and kerosene has been studied. When a fuel cell is used for consumer or automobile use, the petroleum hydrocarbon oil is easy to store and handle, and has a supply system such as a gas station or a store. It is advantageous as When hydrogen is produced using this petroleum-based hydrocarbon oil, generally, a method of steam-reforming the hydrocarbon oil in the presence of a reforming catalyst is used.

In such a steam reforming treatment, a method using a nickel-based catalyst or a noble metal-based catalyst as a reforming catalyst has been conventionally performed. For example, Japanese Patent Publication No. 53-1
Japanese Patent No. 2817 discloses a method of using a nickel-based catalyst supported on an alumina carrier using metal nickel or the like as a catalytic active component, and Japanese Patent Publication No. 53-12817 and Japanese Patent Application Laid-Open No. 56-91844 disclose a method. A method using a noble metal catalyst in which rhodium, ruthenium, platinum or the like is supported on a carrier such as alumina or zirconia is disclosed. However, the reaction using the above nickel catalyst has a disadvantage in that unless the reaction is carried out at a high steam / carbon ratio (moles of H ₂ O / C atoms), the precipitation of carbon becomes large and the catalyst life is shortened. In addition, a reaction using a noble metal catalyst has the advantages that the steam / carbon ratio can be made low, carbon deposition can be suppressed, and the catalyst life can be prolonged. However, there is a disadvantage that the catalyst cost is increased. Japanese Patent Publication No. 40-22743 discloses that when a nickel catalyst is used, the nickel content and the alkali metal content of the cocatalyst are made different between the upstream side and the downstream side of the catalyst layer according to the intended reaction. A method for reducing carbon deposition by using a catalyst layer is disclosed. However, even with this method, the steam / carbon ratio was still high. Further, when any of the above-mentioned conventional catalysts is used for producing hydrogen for fuel cells, the catalytic activity is not practically sufficient, and a reforming catalyst having higher activity has been desired.

[0004]

The present invention has been made under such circumstances. That is, the present invention can reduce the deposition of carbon at a low steam / carbon ratio, and can use industrially high-activity and long-life catalysts equivalent to or more than the use of a noble metal catalyst alone. The present invention provides a method for steam reforming hydrocarbons, which is advantageous in terms of efficiency.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies in view of the above-mentioned problems, and as a result, have found that a 2
It has been found that the object of the present invention can be achieved by combining a catalyst comprising the above catalyst layer, specifically, a first-stage catalyst for decomposing hydrocarbons and a second-stage catalyst for reforming hydrocarbons. The present invention has been completed based on such findings. That is, the present invention provides a steam reforming method for reforming hydrocarbons by supplying hydrocarbons and steam to a catalyst layer, wherein the catalyst layer comprises an upstream catalyst layer made of a heat-resistant ceramic, a ruthenium component and a rhodium component. And a downstream catalyst layer containing at least one selected from nickel components.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the steam reforming method of the present invention, a catalyst layer (hereinafter sometimes referred to as a heat-resistant ceramic catalyst) made of a heat-resistant ceramic is provided on the upstream side, and a ruthenium component and rhodium are provided on the downstream side. A catalyst system provided with a catalyst (hereinafter sometimes referred to as a supported catalyst such as ruthenium) layer containing a metal component selected from a metal component and a nickel component is used. First, a supported catalyst such as ruthenium used for the downstream catalyst layer will be described. The supported catalyst such as ruthenium is obtained by supporting at least a metal component selected from a ruthenium component, a rhodium component and a nickel component on a carrier. Examples of usable carriers include silica, alumina, silica-alumina, titania, and zirconia. , Magnesia, zinc oxide, clay, clay and diatomaceous earth. These may be used alone,
Two or more kinds may be used in combination. Among these,
In the present invention, alumina is preferred.

The metal component supported on the carrier includes a ruthenium component, a rhodium component or a nickel component (hereinafter sometimes referred to as a ruthenium component), and a ruthenium component is particularly preferred. In the present invention, it is preferable that 0.05 to 5% by weight of a ruthenium component is supported on the carrier in terms of metal. Ruthenium component 0.05% by weight
If the amount is less, the effect as the active ingredient is not sufficient, and if it exceeds 5% by weight, the effect corresponding to the increase in the supported amount cannot be obtained, which is uneconomical. From this viewpoint, the amount of the supported ruthenium component on the carrier is more preferably 0.05 to 2% by weight, particularly 0.1 to 2% by weight in terms of metal. The rhodium component is preferably carried in the same amount as the ruthenium component, but the nickel component is preferably 2-70% by weight in terms of metal in terms of activity.

The ruthenium-supported catalyst preferably further contains a zirconium component and / or a cobalt component as a support component in the ruthenium component or the like from the viewpoints of enhancing activity and improving heat resistance. Zirconium component is preferably 0.05 to 20 wt% supported in terms of ZrO ₂ on the support. 0.05% by weight of zirconium component
When the amount is less than the above, the effect as the active ingredient is not sufficient, and when it exceeds 20% by weight, the effect corresponding to the increase in the supported amount cannot be obtained, which is uneconomical. From this point, the loading amount of the zirconium component on the carrier is 0.1 to 0.1 in terms of ZrO _2.
It is preferably 15% by weight, especially 1.0 to 15% by weight. The cobalt component is 0.01 in atomic ratio (Co / Ru) of cobalt atom (Co) and, for example, ruthenium atom (Ru).
It is preferable to set the amount to be 30. The above atomic ratio is 0.
If it is smaller than 01, the activity improving effect may not be sufficiently obtained. When the atomic ratio exceeds 30, the amount of ruthenium relatively decreases, and it may be difficult to maintain high activity as a reforming catalyst. From this point, the atomic ratio (Co / Ru) is 0.1 to 30, especially
It is preferably 0.1 to 10.

The activity of a supported catalyst such as ruthenium is enhanced,
From the viewpoint of improving heat resistance, it is preferable that at least one selected from the group consisting of an alkali metal component, an alkaline earth metal component, and a rare earth component is further contained as a support component. Examples of the alkali metal component, alkaline earth metal component and rare earth component include Li, Na, K, Rb, Cs, Be,
Mg, Ca, Sr, Ba, Y, La, Ce, Pr, N
d, Pm, Sm, Eu, Gd, Tb, Dy, Ho, E
Examples of each component include r, Tm, Yb, and Lu. In the present invention, a magnesium component is preferably used from the viewpoint of realizing a highly active catalyst and improving heat resistance. The alkali metal component, the alkaline earth metal component and the rare earth component are preferably supported on the carrier in an amount of 0.5 to 20% by weight in terms of oxide. When the content of the metal component is less than 0.5% by weight, the effect as the active component is not sufficient, and
If the amount exceeds 0% by weight, the effect corresponding to the increase in the supported amount cannot be obtained, which is uneconomical. From this point, the loading amount of the metal component on the carrier is more preferably 0.5 to 15% by weight, particularly preferably 1 to 10% by weight in terms of oxide.

In the method of the present invention, the method of supporting the metal component on a carrier is not particularly limited.
For example, at least one or more of ruthenium, rhodium and nickel (hereinafter sometimes referred to as a ruthenium compound), a zirconium compound and / or a cobalt compound, if necessary, It can be supported by contacting and impregnating a solution containing one or more kinds of alkali metal compounds, alkaline earth metal compounds and rare earth element compounds (preferably one or more magnesium compounds). . The solution used for this loading contains the ruthenium compound and the like, but is preferably adjusted to be acidic, preferably at pH 3 or less, more preferably at pH 1.5 or less. When the pH exceeds 3, the respective compounds tend to precipitate or agglomerate in a gel state, so that it is difficult to carry out high dispersion loading. When the pH is 3 or less, it is considered that the ruthenium compound and the like and the zirconium compound and the like react with each other to form a complex-like compound, thereby exhibiting excellent properties. As the solvent of the solution used for this support, for example, water or an aqueous solvent containing water as a main component, an alcohol, an organic solvent such as ether, and at least as long as the above metal compound is dissolved, No restrictions.

The type and form of the supported metal source are not particularly limited as long as they can be dissolved in the above-mentioned solvent, and examples thereof include the following.
Ruthenium compounds used as ruthenium sources include:
For example, various ruthenium halides such as ruthenium trichloride, various ruthenium halides such as ruthenium nitrate and potassium hexachlororuthenate, various ruthenates such as potassium tetraoxoruthenate, ruthenium tetroxide, ruthenium hexaammine Examples thereof include, but are not limited to, various ammine complex salts such as trichloride, and cyano complex salts such as potassium hexacyanoruthenate. Among these various ruthenium compounds, ruthenium trichloride is particularly preferable because it is widely used industrially and easily available. These ruthenium compounds may be used alone or in combination of two or more. As for the rhodium compound or the nickel compound, various halides, acid salts, ammine complex salts, cyano complex salts and the like are used in the same manner as the above ruthenium compound.

Zirconium used as zirconium source
Similarly, compounds exhibit solubility in certain solvents.
By adding an acid such as hydrochloric acid or an acidic compound, etc.
Use a solution that can be dissolved in a solvent
Can be used. Specifically, for example,
Various halides such as conium and their partial additions
Water decomposition product, zirconyl chloride (zirconium oxychloride)
Various oxyhalides such as zirconyl sulfate,
Various oxygen acids such as zirconium nitrate and zirconyl nitrate
Salt, potassium tetraoxozirconate, hexaflur
Various zirconium such as sodium odisilconate
Acid salt, zirconium acetate, zirconyl acetate, zirconium oxalate
Nil, potassium tetraoxalatozirconate, etc.
Some organic acid salts or organic coordination compounds,
Are zirconium alkoxides, hydroxides and various complex
Salts and the like can be mentioned. These various zirconium
Oxychlorination of zirconium
Are preferred, for example, ZrOCl_Two・ NH_TwoO or Zr
O (OH) Cl.nH _TwoHydrates represented by O
Such as those that are commercially available in a state like ruthenium and complex
Because it is easy to produce a compound, it can be suitably used.
Wear. In addition, these zirconium compounds may be used alone.
Or two or more of them may be used in combination.

Similarly, the cobalt compound used as a cobalt source may be soluble in a certain solvent or may be dissolved by adjusting the pH by adding an acid such as hydrochloric acid or an acidic compound. Can be used. Usually, highly soluble compounds such as nitrates and chlorides are preferably used. Specific examples include cobaltous nitrate, basic cobalt nitrate, cobalt dichloride, nickel nitrate, nickel chloride, and various hydrates thereof. Among them, cobaltous nitrate and the like are particularly preferable. These cobalt compounds may be used alone or in combination of two or more. Similarly, a metal compound used as an alkali metal source, an alkaline earth metal source, and a rare earth element source is dissolved in a certain solvent or dissolved by adding an acid or an acidic compound such as hydrochloric acid to an aqueous solution. Anything that can be used can be used. Usually, compounds having high solubility such as nitrates and chlorides can be suitably used, and examples thereof include magnesium nitrate and magnesium chloride. Among these various metal compounds, magnesium nitrate and various hydrates thereof can be particularly preferably used. These metal compounds may be used alone or in combination of two or more.

There are no particular restrictions on the order and method of addition, mixing, and dissolution of the components such as the solvent, ruthenium compound, and acid. Acids added as needed for improving solubility and adjusting pH include, for example, hydrochloric acid,
Various substances such as inorganic acids such as sulfuric acid and nitric acid and organic acids such as acetic acid and oxalic acid may be appropriately selected and used. The impregnating and supporting operation by contacting the solution prepared as described above with a carrier can be performed according to a conventional method. For example, various impregnation methods (heating impregnation method, room temperature impregnation method, vacuum impregnation method, normal pressure impregnation method, impregnation drying method, pore filling method, or any combination thereof, etc.), immersion method, mild infiltration method , A wet adsorption method, a spray method, a coating method, etc., or a combination thereof, and any method may be used as long as the solution and the carrier are brought into contact with each other and supported. Further, in the present invention, it is necessary to perform the series of operations of the impregnation support and the drying at least once, but if necessary, these operations may be repeated a plurality of times. Here, the amount ratio of the carrier and the solution to be used depends on the target loading ratio of the active metal component, the concentration of the metal compound in the aqueous solution to be used, the type of the impregnation-supporting operation method, the pore volume and the specific surface area of the carrier to be used. And can be determined appropriately.

This contacting operation (impregnation carrying operation) can be suitably performed under atmospheric pressure or reduced pressure (under reduced pressure exhaustion) as in the conventional case, and the operating temperature at that time is not particularly limited. Can be carried out at or near room temperature, and if necessary, by heating or heating, for example, from room temperature to 8
It can be suitably performed even at a temperature of about 0 ° C. The drying after the contact between the solution and the carrier is not particularly limited, but is usually performed at 50 to 150 ° C, preferably 100 to 120 ° C for 1 hour or more. In air drying at room temperature, one day (24 hours)
Time) about. However, depending on the impregnation-supporting method, a large amount of water evaporates and a considerably dry state is obtained. In such a case, a separate drying operation is not necessarily required. The calcination may not be performed, but when it is performed, the calcination can be performed according to a conventional method.
It is performed in a temperature range of 00 ° C. In addition, oxygen-containing gas such as pure oxygen or oxygen-enriched air may be used in place of or in combination with air. Usually, a firing time of about 1 to 24 hours is sufficient.

The shape of the supported catalyst such as ruthenium obtained as described above is not particularly limited.
Arbitrary shapes such as fine powder, beads, pellets, and plates can be adopted. The catalyst obtained as described above can be used as it is, but if necessary,
It may be activated by various appropriate pretreatments before use in the catalytic reaction. This pretreatment can be performed according to a conventional method, for example, by appropriately reducing with a reducing agent such as hydrogen,
The ruthenium component or the like may be converted into highly dispersed metallic ruthenium or the like and then subjected to the reaction. In the dispersion metallization treatment by hydrogen reduction, for example, reduction is preferably performed at 300 to 850 ° C. until consumption of hydrogen is not recognized.

Next, in the present invention, the heat-resistant ceramic catalyst used as the upstream catalyst includes silica,
Examples include alumina, silicon carbide, tungsten carbide, molybdenum carbide, cordierite, zirconia, and titania. In the present invention, alumina is preferably used. Further, in the present invention, it is preferable that at least one selected from an alkali metal component, an alkaline earth metal component, and a rare earth component is supported on the heat-resistant ceramic from the viewpoint of enhancing the activity. In particular,
It is preferable to use alkali metal components such as potassium and sodium. As such an alkali metal component, an alkaline earth metal component and a rare earth component, those similar to those used for the above-mentioned supported catalyst such as ruthenium can be prepared and used in the same manner. The shape of the heat-resistant ceramic catalyst is not particularly limited. For example, any shape such as a fine powder, a bead, a pellet, and a plate can be adopted.

In the present invention, the upstream catalyst layer made of a heat-resistant ceramic catalyst is used in an amount of 10 to 50% by volume, preferably 10 to 30% by volume of the total catalyst amount, and the downstream catalyst layer made of a supported catalyst such as ruthenium is entirely used. It is preferable that the amount of the catalyst be 90 to 50% by volume, preferably 90 to 70% by volume, in order to achieve the object of the present invention. That is, when the amount of the upstream catalyst layer is smaller than the above range, the decomposition of the hydrocarbon is not sufficient, and the carbon deposition may not be sufficiently suppressed. On the other hand, when the amount of the downstream catalyst layer is less than the above range, the steam reforming reaction may be insufficient, which is not preferable.

Hereinafter, the steam reforming reaction will be described.
As the raw material hydrocarbon used in this reaction, for example,
Linear or branched saturated aliphatic hydrocarbons having about 1 to 16 carbon atoms, such as methane, ethane, propane, butane, pentane, hexane, heptane, octane, nonane, decane, cyclohexane, methylcyclohexane, cyclooctane, etc. Alicyclic saturated hydrocarbons, monocyclic and polycyclic aromatic hydrocarbons, city gas having a boiling range of 300 ° C. or less, LPG,
Examples include various hydrocarbons such as naphtha and kerosene. In the present invention, the effect is particularly large when a raw oil composed of a hydrocarbon having a high molecular weight such as kerosene is used as the hydrocarbon. In particular, the sulfur content is 80 ppm by weight.
It is preferably applied to the following JIS No. 1 kerosene. This J
IS-1 kerosene is obtained by desulfurizing crude kerosene obtained by distilling crude oil at normal pressure. The crude kerosene usually has a high sulfur content, and does not become JIS No. 1 kerosene as it is, and it is necessary to reduce the sulfur content. As a method for reducing the sulfur content, desulfurization treatment is preferably performed by a hydrorefining method generally used industrially.

In general, when sulfur is present in these raw material hydrocarbons, desulfurization is performed through a desulfurization step prior to the steam reforming step, usually until the sulfur content becomes about 0.1 ppm or less. Is preferred. When the sulfur content in the raw material hydrocarbon is more than about 0.1 ppm, it may cause deactivation of the reforming catalyst. Although the desulfurization method is not particularly limited, hydrodesulfurization, adsorption desulfurization and the like can be used as appropriate. The steam to be reacted with the steam hydrocarbon is not particularly limited. When reacting a hydrocarbon with water vapor, the amount of hydrocarbon and the amount of water vapor are usually determined so that the steam / carbon ratio becomes 1.5 to 10, preferably 1.5 to 5, and more preferably 2 to 4. Is preferred.
With such a steam / carbon ratio, a product gas having a high hydrogen content can be efficiently obtained.

The reaction temperature is usually from 200 to 900 ° C, preferably from 250 to 900 ° C, more preferably from 300 to 900 ° C.
800 ° C. The reaction pressure is usually 0 to 3 MPa.
G, preferably 0 to 1 MPa · G. In particular, in the present invention, the temperature of the upstream catalyst layer is set to 600 to 800 ° C,
The temperature is preferably 700 to 800 ° C, and the temperature of the downstream catalyst layer is 400 to 800 ° C, preferably 500 to 800 ° C.
And If these temperatures deviate from the above ranges, hydrocarbon decomposition and steam reforming reactions become insufficient, which may be undesirable. The reaction system is not particularly limited, but a continuous flow system is preferred. When the continuous flow method is adopted, the space velocity (GHSV) of the mixed gas of hydrocarbon and steam is usually 1,000 to 100,000 h ^-1 , preferably 2,
000 to 50,000 h ^-1 , more preferably 2,000
0 to 40,000 h ^-1 .

The reaction system is not particularly limited, and examples thereof include a fixed bed system, a moving bed system and a fluidized bed system.
The type of the reactor is not particularly limited, and for example, a tubular reactor or the like can be used. By reacting a hydrocarbon with steam using the method of the present invention under the above conditions, a mixture containing hydrogen can be obtained, which is suitably employed in a hydrogen production process of a fuel cell.

[0023]

EXAMPLES Next, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. Preparation of Catalyst (1) Catalyst 1 20 g of α-alumina molded article carrier (3 mm diameter sphere)
The catalyst was dried overnight at 20 ° C. and calcined at 500 ° C. for 2 hours to obtain a catalyst 1. (2) Catalyst 2 0.85 g of sodium nitrate (NaNO ₃ ) was dissolved in 4 ml of water to obtain an impregnation liquid. 20 g of this impregnating liquid was applied to an α-alumina molded body carrier (spherical having a diameter of 3 mm).
Was impregnated and supported by a pore filling method. After loading, the supported catalyst was dried at a temperature of 120 ° C. overnight, and further calcined at 500 ° C. for 2 hours to obtain a catalyst 2. The content of the metal element by composition analysis of the obtained catalyst was Na: 1.0% by weight.

(3) Catalyst 3 Ruthenium trichloride was added to 7.1 g of an aqueous solution of zirconium oxychloride (ZrO (OH) Cl) (containing 35% as ZrO ₂ , manufactured by Daiichi Rare Element Industry Co., Ltd .: ZC-2). (RuC
0.66 g of l ₃ .nH ₂ O: containing 38% of Ru, 6.36 of magnesium nitrate (Mg (NO ₃ ) 2 .6H ₂ O)
g, and cobalt nitrate _{(Co (NO 3) 3 ·} 6H 2 O)
2.47 g were dissolved to make the total amount of the solution 10 ml. A solution obtained by stirring this solution with a stirrer for 1 hour or more was used as an impregnating liquid. This impregnating liquid was impregnated and supported on 50 g of an α-alumina molded article carrier (spherical having a diameter of 3 mm) by a pore filling method. After loading, the supported catalyst was dried at a temperature of 120 ° C. overnight to obtain Catalyst 3. (4) Catalyst 4 Catalyst 3 was obtained except that catalyst 3 was further calcined at 500 ° C. for 2 hours.
Catalyst 4 was obtained in the same manner as in the preparation of

Example 1 1.5 ml of catalyst 1 was pulverized to a diameter of 0.5 to 1 mm and charged in an upper portion of a reaction tube having an inner diameter of 10 mm.
Two milliliters were similarly crushed to a diameter of 0.5 to 1 mm and filled. After reducing the catalyst with hydrogen in a hydrogen stream at 600 ° C. for 1 hour in a reaction tube, the sulfur concentration was 0.1 wt.
JIS No. 1 kerosene desulfurized to pm or less was used as a raw material oil, and JIS No. 1 kerosene and steam were supplied from the top of the reaction tube under the conditions of LHSV: 9.6 h ^-1 and steam / carbon ratio (S / C) = 1.5. Introduce one layer of catalyst at 700 ° C, catalyst 3
The layer was heated to 650 ° C. to perform a steam reforming reaction. The obtained gas was sampled and its concentration was measured by gas chromatography. Based on this result, the C1 conversion was determined by the following equation. The results are shown in Table 1. C1 conversion rate (%) = (A / B) × 100 [where A = CO molar flow rate + CO ₂ molar flow rate + CH ₄ molar flow rate (both flow rates at the reactor outlet), B = kerosene at the reactor inlet side Is the carbon molar flow rate. The amount of coke deposited on the catalyst 3 was measured by a combustion-infrared absorption method. The results are shown in Table 1.

Example 2 A steam reforming reaction was carried out in the same manner as in Example 1 except that the catalyst 1 in the upper part of the reaction tube was replaced with the catalyst 2, and the C1 conversion rate and the coke deposition amount were determined. The results are shown in Table 1. Example 3 A steam reforming reaction was performed in the same manner as in Example 1 except that the catalyst 3 at the lower part of the reaction tube was replaced with the catalyst 4, and the C1 conversion was determined. The results are shown in Table 1. Comparative Example 1 A steam reforming reaction was carried out in the same manner as in Example 1 except that the catalyst 1 was not used and only the catalyst 3 was used, and the C1 conversion rate and the coke deposition amount were determined. The results are shown in Table 1. Comparative Example 2 In Example 3, a steam reforming reaction was carried out in the same manner as in Example 3 except that only Catalyst 4 was used without using Catalyst 1, and the C1 conversion rate and the coke deposition amount were obtained. The results are shown in Table 1.

[0027]

[Table 1]

[0028]

According to the present invention, the deposition of carbon can be reduced at a lower steam / carbon ratio than when a nickel-based catalyst is used. By using a catalyst having a long life, an industrially useful method for steam reforming of hydrocarbons can be provided. Further, according to the present invention, the amount of the reforming catalyst used can be reduced, which can contribute to cost reduction.

Continued on the front page F-term (reference) 4G040 EA03 EA06 EB16 EC02 EC03 EC04 EC05 4G069 AA03 AA08 BA01A BA01B BA02A BA04A BA05A BA13A BB06B BB15A BC01A BC02B BC08A BC10B BC38A BC51A BC51B BC59A BC60BBC BCA BC67 BC67 DA67

Claims (8)

[Claims] 1. A steam reforming method for reforming hydrocarbons by supplying hydrocarbons and steam to a catalyst layer, said catalyst layer comprising an upstream catalyst layer made of a heat-resistant ceramic, a ruthenium component, a rhodium component and A steam reforming method for hydrocarbons, comprising at least a downstream catalyst layer containing at least one selected from nickel components. 2. The proportion of the upstream catalyst layer is 10 to 10% of the total amount of the catalyst.
50% by volume, the ratio of the downstream catalyst layer is 90 to 5% of the total catalyst amount.
The steam reforming method according to claim 1, wherein the content is 0% by volume. 3. The steam reforming method according to claim 1, wherein the upstream catalyst layer comprises at least one selected from the group consisting of an alkali metal component, an alkaline earth metal component, and a rare earth element component, supported on a heat-resistant ceramic. Quality way. 4. The steam reformer according to claim 1, wherein the heat-resistant ceramic is at least one selected from silica, alumina, silicon carbide, tungsten carbide, molybdenum carbide, cordierite, zirconia, and titania. Quality way. 5. The downstream catalyst layer comprises a catalyst having at least a ruthenium component supported on an alumina carrier.
5. The steam reforming method according to any one of 4. 6. The steam reforming method according to claim 5, wherein the downstream catalyst layer comprises a catalyst further containing a zirconium component and / or a cobalt component as a supported component. 7. The steam reforming according to claim 5, wherein the downstream catalyst layer comprises a catalyst further containing at least one selected from the group consisting of an alkali metal component, an alkaline earth metal component and a rare earth element component as a supported component. Method. 8. The temperature of the upstream catalyst layer is set at 600 to 800 ° C.
The steam reforming method according to any one of claims 1 to 7, wherein the temperature of the downstream catalyst layer is set to 400 to 800 ° C.