JPH0929097A - Steam reforming catalyst of hydrocarbon - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a steam reforming catalyst of hydrocarbon markedly excellent in activity per supported ruthenium, having high activity and excellent in heat resistance capable of keeping high activity even at high temp. at a time of baking or reaction. SOLUTION: This catalyst is constituted by adding ruthenium, zirconium and magnesium components to an α-alumina carrier and characterized by that the content of the magnesium component is 0.5-20wt.% in terms of magnesium metal and an Mg/Zr mol ratio is 0.5-5.0.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydrocarbon steam reforming catalyst, and more particularly to a catalyst having ruthenium as an active ingredient, which has high activity and excellent heat resistance, and has been incorporated into various hydrogen production processes, particularly fuel cells. The present invention relates to a hydrocarbon steam reforming catalyst suitably applied to a hydrogen production process.

[0002]

2. Description of the Prior Art A catalyst for steam reforming of hydrocarbons containing a ruthenium component exhibits excellent catalytic performance that is highly active and excellent in carbon deposition resistance even under operating conditions of low steam / carbon ratio. Recently, it has been widely used in fuel cells that require a long-life steam reforming catalyst under low steam / carbon ratio operating conditions. For that purpose, development of a catalyst having high activity and excellent heat resistance has been demanded.

Since ruthenium is a noble metal, catalysts containing it are generally expensive. Therefore, in order to popularize the industrial use of the catalyst containing the ruthenium component, it is necessary to reduce not only the catalyst performance but also the catalyst price.

Regarding the catalyst containing the ruthenium component,
Japanese Unexamined Patent Publication (Kokai) No. 5-220397 discloses a hydrocarbon steam reforming catalyst in which aluminum oxide containing an alkaline earth metal aluminate is loaded with zirconium oxide having a zirconia sol as a precursor and a ruthenium component. .

In this catalyst, since the zirconia sol itself has a particle size of 100 angstroms or more, it is considered that the zirconium oxide particles produced from this catalyst are growing large. In addition, it is considered that the alkaline earth metal aluminate is in a crystal phase and the particles grow large similarly to zirconium oxide. Therefore, with this catalyst, a catalyst having sufficient activity cannot be obtained, especially with a low surface area support.

[0006]

It is an object of the present invention that the activity per supported ruthenium is remarkably excellent and the activity is high, and the carbonization is excellent in heat resistance to maintain the high activity even at high temperature during firing and reaction. It is to provide a catalyst for steam reforming of hydrogen.

[0007]

Means for Solving the Problems As a result of intensive studies for achieving the above object, the present inventors have found that a catalyst containing a ruthenium component, a zirconium component and a magnesium component in an α-alumina carrier has high activity, They have found that they are also excellent in heat resistance, and have completed the present invention based on this finding.

That is, the present invention is a catalyst in which a ruthenium component, a zirconium component and a magnesium component are contained in an α-alumina carrier, and the content of the magnesium component is 0.5 to 20% by weight in terms of magnesium metal. And a Mg / Zr molar ratio of 0.5 to 5.0, which provides a hydrocarbon steam reforming catalyst.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION In the catalyst of the present invention, the zirconium component and the magnesium component are zirconium oxide,
It exists in the form of fine particles such as magnesium oxide, and because it does not crystallize due to the interaction between the two, particle growth does not occur, so the surface area of the carrier becomes extremely large, making it a highly active catalyst, and also a catalyst with excellent heat resistance. can get.

The final supported amount of each supported component may be appropriately selected in consideration of properties such as the type and surface area of the carrier, or various conditions such as the use of the catalyst, that is, the type and properties of the reaction to be targeted. . In many cases, the amount of the ruthenium component converted to the ruthenium metal is usually 0.05 to 5% by weight, preferably 0.05 to 5% by weight, based on the weight of the carrier.
2% by weight, more preferably 0.1 to 1% by weight, and the zirconium component is usually converted to zirconium metal in an amount of 0.1.
05 to 20% by weight, preferably 0.1 to 15% by weight, more preferably 1.0 to 10% by weight, and the magnesium component is generally 0.5 to 20 in terms of magnesium metal.
It is suitable to select in the range of 0.5% by weight, preferably 0.5 to 15% by weight. The content of magnesium component is 0.5
If it is less than wt%, the catalytic activity will decrease.

The ratio of the magnesium component and the zirconium component contained in the catalyst is expressed by the molar ratio (Mg / Zr) of magnesium atom (Mg) and zirconium atom (Zr). Is 0.1-10.
0, preferably 0.5 to 5.0, more preferably 0.5
Select to be in the range of up to 2.0. Here, if
If the molar ratio (Mg / Zr) is less than 0.1, the effect of suppressing the decrease in the surface area of the supported component cannot be obtained, and the effect of improving heat resistance becomes insufficient. On the other hand, even if this molar ratio is made larger than 10.0, it is difficult to obtain the corresponding effect of improving the heat resistance.

The catalyst of the present invention preferably contains a cobalt component in order to further enhance the activity of the catalyst. When the amount of the cobalt component is represented by a molar ratio (Co / Ru) of cobalt atom (Co) and ruthenium atom (Ru), the molar ratio (Co / Ru) is usually 0.01 to 3
0, preferably 0.1 to 30, more preferably 0.1 to
It is preferable to select the value within the range of 10. Here, if the molar ratio is less than 0.01, the ratio of the cobalt component decreases, and the effect of improving the activity may not be obtained as expected. On the other hand, even if this molar ratio is made larger than 30, the amount of ruthenium becomes relatively small, and even under the operating conditions of high activity of a hydrocarbon containing a ruthenium component as a steam reforming catalyst and a low steam / carbon ratio. The effect of suppressing carbon deposition may be impaired.

In the catalyst of the present invention, the ratio I _S / I of the strongest peak intensity I _S of X-ray diffraction of compounds other than α-alumina to the strongest peak intensity I _A of X-ray diffraction of α-alumina.
The value of _A is preferably 0.01 or less. In the case where this value exceeds 0.01, the catalytic activity tends to decrease.

The catalyst of the present invention comprises, for example, α-alumina and at least one or more ruthenium compounds, one or more zirconium compounds, and one or more magnesium compounds. It can be produced by contact impregnation with a solution containing one or more cobalt compounds dissolved therein, if necessary. By such a method, the ruthenium component or the ruthenium component and the cobalt component and the zirconium component and the magnesium component can be evenly supported on the surface and the pores of the catalyst carrier with good dispersibility, and thereafter, usually performed. Even if pretreatment such as firing or reduction at high temperature is performed, it is possible to maintain a sufficiently dispersed state of the ruthenium component or the ruthenium component and the cobalt component, the zirconium component, and the magnesium component in a sufficiently stable manner. A supported ruthenium-based catalyst can be easily obtained.

The solution used for producing the catalyst contains a ruthenium compound, a zirconium compound, a magnesium compound and, if necessary, a cobalt compound, but it is desirable to adjust it to be acidic. At that time, the pH is preferably adjusted to 3 or less, more preferably 1.5 or less. This is because when the pH becomes high, the respective compounds tend to precipitate or aggregate in a gel state, which makes it difficult to carry out high dispersion. Further, as shown below, the ruthenium compound and the zirconium compound and the magnesium compound react with each other to form a complex-like compound, whereby I _S / I _A
Is considered to be 0.01 or less.

Examples of the solvent of the solution used for producing the catalyst of the present invention include water, an aqueous solvent containing water as a main component, and an organic solvent such as alcohol and ether.
A ruthenium compound, a zirconium compound, a magnesium compound and a cobalt compound used as necessary can be freely selected as long as they are dissolved. Among them, highly soluble water or an aqueous solvent containing water as a main component is preferably used. In addition, as each compound used as a raw material for its preparation, generally any kind or form may be used as long as it can be dissolved in a solvent.

That is, the ruthenium compound used as the starting material is usually, for example, various ruthenium halides such as ruthenium trichloride and various halogenated ruthenium salts such as potassium hexachlororuthenate.
Various ruthenium salts such as potassium tetraoxorthenate, ruthenium tetroxide, various ammine complex salts such as hexaammineruthenium trichloride, cyano complex salts such as potassium hexacyanoruthenate are preferably used, but are not limited to these. However, it is not limited to those that are soluble in a certain solvent, and various types can be used as long as they can be sufficiently dissolved by the addition or coexistence of an acid or an acidic compound. Therefore, for example, ruthenium oxide such as diruthenium trioxide and ruthenium hydroxide,
Alternatively, even an oxyhalide or the like that is insoluble or difficult to dissolve in water having a pH of about 7 can be used by appropriately adding an acid such as hydrochloric acid and dissolving it.

Among these various starting ruthenium compounds, ruthenium trichloride is particularly preferably used because it is widely used industrially and is easily available. In addition,
These ruthenium compounds may be used alone or in combination of two or more.

Similarly, with respect to the zirconium compound, a compound which is soluble in a certain solvent, or an acid such as hydrochloric acid or an acidic compound is dissolved in the solvent as an acidic solvent to form a solution. Various materials capable of producing can be used as a raw material for preparation. Specifically, for example, various halides such as zirconium tetrachloride or partial hydrolysis products thereof, various oxyhalides such as zirconyl chloride (zirconium oxychloride), various kinds of zirconyl sulfate, zirconium nitrate, zirconyl nitrate, etc. Oxygenates, potassium tetraoxozirconate, various zirconates such as sodium hexafluorozirconate, zirconium acetate, zirconyl acetate, zirconyl oxalate, various organic acid salts such as potassium tetraoxalatozirconate Coordination compounds, etc.
Furthermore, alkoxide of zirconium, hydroxide, various complex salts, etc. can be illustrated.

Of these various zirconium compounds, zirconium oxychloride is particularly preferable. For example, ZrOCl ₂ .nH ₂ O and ZrO (OH) Cl.n.
A hydrate represented by H ₂ O, a commercially available product in the form of a solution, and the like are preferably used because they easily form a complex-like compound with ruthenium. These zirconium compounds may be used alone or in combination of two or more.

Similarly, the magnesium compound may be one that is soluble in a certain solvent, or one that can be dissolved into an aqueous solution by adding an acid such as hydrochloric acid or an acidic compound. It can be used as a preparation raw material. Usually, highly soluble compounds such as nitrates and chlorides are preferably used. Specific examples of the magnesium compound include magnesium nitrate and magnesium chloride.

Similarly, as the cobalt compound used as necessary, those which are soluble in a certain solvent,
Various substances that can be dissolved by adjusting the pH by adding an acid such as hydrochloric acid or an acidic compound can be used as the preparation raw material. Usually, highly soluble compounds such as nitrates and chlorides are preferably used. Specifically, for example, cobaltous nitrate, basic cobalt nitrate,
Examples thereof include cobalt dichloride and various hydrous salts thereof. Of these, cobaltous nitrate is particularly preferably used. These cobalt compounds may be used alone or in combination of two or more.

When preparing the above-mentioned solution used in the present invention, there is no particular limitation on the order and method of addition, mixing and dissolution of the solvent, ruthenium compound, zirconium compound, magnesium compound, cobalt compound and acid. . For example, a predetermined component may be simultaneously added and dissolved in a solvent or an acidic solution to which an acid has been added, or may be added stepwise and dissolved, or a solution of each component may be prepared separately. However, these solutions may be mixed,
After preparing a solution of some components, the remaining components may be dissolved in the solution. At this time, the liquid temperature is preferably about room temperature, but may be heated up to about 80 ° C. to promote dissolution.

As the acid to be added as necessary for improving the solubility and adjusting the pH, various acids such as inorganic acids such as hydrochloric acid, sulfuric acid and nitric acid, and organic acids such as acetic acid and oxalic acid are used. It may be appropriately selected and used. At this time, the pH is adjusted to a relatively strong acidity, preferably 3 or less, more preferably 1.5 or less. Adjust the pH to 3 or 1.
When it is higher than 5, various compounds described above may be precipitated.

Further, since the basicity of the obtained catalyst body tends to be strong, for example, when the contact between the carrier and the solution is divided into several times, the carrier and the solution are contacted with each other after the second contact. When this is done, each component in the solution, mainly the zirconium component, gels before moving onto the carrier, which may make it impossible to support the carrier surface in a highly dispersed state.

The amount (concentration) of each compound to be dissolved in the above solution is not particularly limited, but the concentration of the ruthenium compound is usually the molar concentration of ruthenium atoms.
0.001 mol / l or more, preferably 0.01 to 10
It is preferable to select it so that it is mol / l, more preferably 0.02 to 2 mol / l.

The above solution used in the present invention may appropriately contain other components other than the rare earth element compound and the acid for adjusting the solubility as long as the object of the present invention is not impaired.

As a method for uniformly dissolving each compound, it is usually possible to lower the pH of the solution. Specifically, it is desirable to adjust the pH to 3 or less, preferably 1.5 or less. Here, if the pH of the solution is higher than 3 or 1.5, the zirconium compound is easily hydrolyzed, and a hydroxide-like sol or gel is easily formed. Hydroxide-like sols and gels generated in such a solution are unlikely to form the above-mentioned complex-like compound with the ruthenium component, so that the effect of improving dispersibility and the like cannot be achieved as expected. There is a risk.

As the carrier, α-alumina is used. When α-alumina is used as the carrier, the ruthenium component and zirconium oxide are likely to be immobilized in the carrier when the solution comes into contact with the carrier.

In preparing the catalyst of the present invention, α-
As in the conventional case, the alumina carrier can be used as the one whose composition and physical properties are adjusted or controlled by addition of additives, execution of pretreatment, selection of preparation method and the like. For example, chemical treatment such as acid treatment, base treatment, and ion exchange treatment is performed to adjust the acidity,
Adjust the water content and OH content by heating or baking,
Furthermore, control of pore size and pore size distribution by various means,
The composition or the properties as a catalyst carrier may be adjusted or improved by controlling the surface area. Also,
Depending on the case, it is possible to use a material containing or supporting an appropriate metal component in advance. The α-alumina carrier may be dried or calcined in advance, may be uncalcined or undried, or may be in the form of a slurry such as a sol prepared by hydrolysis or the like. It may be one.

The shape and size of the α-alumina carrier is not particularly limited, and may be, for example, powder, beads, pellets, granules, monoliths or the like coated with a structure, fine particles or ultrafine particles. The thing can be used suitably. That is, it may be granulated or molded, or may not be particularly treated.

The impregnation and supporting operation by contacting the above-mentioned solution with the α-alumina carrier can be carried out according to a conventional method. For example, various commonly used impregnation methods (heat impregnation method, room temperature impregnation method, vacuum impregnation method, atmospheric pressure method). Impregnation method, impregnation dryness method, pore filling method, etc., or any combination thereof, etc.),
Immersion method, light infiltration method, wet adsorption method, wet kneading method, spray method, coating method, etc., or a combination thereof,
Any method may be used as long as the solution and the α-alumina carrier are brought into contact with each other and supported. The series of operations of impregnating, supporting, drying and firing is performed at least once, but if necessary, these operations may be repeated twice or more and repeated multiple times.

Here, the amount ratio of the α-alumina carrier to be used and the solution are the target active metal component loading rate, the concentration of the metal compound in the aqueous solution used, the type of the impregnation loading method, the pore volume of the carrier used, and the like. It cannot be uniformly determined because it depends on the specific surface area and the like, but at least an amount of a solution that sufficiently wets the α-alumina carrier to be supported is used, while the upper limit of the amount of the solution used for the α-alumina carrier is used. , There is no particular limitation, but normally α used
-The amount of the solution used is selected within a range of 100 ml or less per 100 g of the dry weight of the alumina carrier, and preferably, the solution is reduced to a water absorption amount close to the water absorption specific to the α-alumina carrier.
More preferably, a solution having a volume corresponding to the amount of absorbed water is used.

This contacting operation (impregnation supporting operation) can be suitably carried out under atmospheric pressure or under reduced pressure (under reduced pressure exhaust) as in the conventional case, and the operating temperature at that time is not particularly limited. It can be carried out at room temperature or near room temperature, and is heated or heated as necessary, for example, room temperature to 80.
It can be suitably performed even at a temperature of about ° C.

The drying after contacting the above solution with the α-alumina carrier is not particularly limited, but usually 50 to 150 ° C.,
It is preferably carried out at 100 to 120 ° C. for 1 to 6 hours.
Air-drying at room temperature is performed for about 24 hours a day. However, depending on the impregnation-supporting method, a large amount of water evaporates and a considerably dried state can be obtained. Therefore, in such a case, a separate drying operation is not necessarily required.

The above-mentioned calcination can also be carried out according to a conventional method, usually 400 to 80 in air or in an air stream.
0 ° C, preferably 450 to 800 ° C, more preferably 4
It is preferably carried out in the temperature range of 50 to 600 ° C. In addition,
In addition to air, an oxygen-containing gas such as pure oxygen or oxygen-enriched air may be substituted or used together. The firing time is usually 1 to
About 24 hours is sufficient.

If desired, the supporting composition may be molded into a predetermined shape and size at any suitable time before firing. When molding is carried out, this molding can be carried out by a conventional method, and if necessary, a suitable binder component may be added.

The ruthenium component, the cobalt component, the zirconium component and the magnesium component in the catalyst obtained by this calcination are usually supported in the form of an oxide or a complex oxide in the vicinity of the respective components in a highly dispersed state.

The catalyst thus obtained can be used as it is as a catalyst or a catalyst component for a predetermined catalytic reaction, but if necessary, various suitable pretreatments are carried out to activate it before the catalytic reaction. You may use. This pretreatment can be performed according to a conventional method. For example, it may be appropriately reduced with a reducing agent such as hydrogen to convert the ruthenium component into highly dispersed metallic ruthenium and used for the reaction.

The dispersion metallization treatment by this hydrogen reduction
Is, for example, H at 500 to 850 ° C. _TwoConsumption of
It is preferable to reduce until it disappears.

There are no particular restrictions on the starting hydrocarbons used in the method for steam reforming of hydrocarbons using the catalyst for steam reforming of hydrocarbons of the present invention, and examples thereof include methane, ethane, propane, butane, pentane, hexane and heptane. , Octane, nonane, decane, etc., straight or branched saturated aliphatic hydrocarbons having about 1 to 16 carbon atoms, alicyclic saturated hydrocarbons such as cyclohexane, methylcyclohexane, cyclooctane, monocyclic and polycyclic Various hydrocarbons such as aromatic hydrocarbons are used. Also, a mixture of two or more of the above various hydrocarbons is used. Other preferable examples include various hydrocarbons having a boiling point range of 300 ° C. or lower, such as city gas, LPG, naphtha, and kerosene. Further, in general, when a sulfur content is present in these raw material hydrocarbons, it is usually desirable to perform desulfurization through the desulfurization step until the sulfur content becomes about 1 ppm or less. This is because if the sulfur content in the raw material hydrocarbon exceeds about 1 ppm, the catalyst may be deactivated. The desulfurization method is not particularly limited, but hydrodesulfurization, adsorptive desulfurization and the like are performed.

There are no particular restrictions on the steam that is reacted with the hydrocarbon.

When the hydrocarbon and steam are reacted, the amount of hydrocarbon and the amount of steam are usually such that the steam / carbon ratio is 1.5 to 10, preferably 1.5 to 5, and more preferably 2 to 4. Is preferably determined. With such a steam / carbon ratio, a product gas having a high hydrogen content can be efficiently obtained. In the steam reforming method of the present invention, carbon precipitation can be suppressed even when the steam / carbon ratio is 3 or less, so that exhaust heat can be effectively used.

The reaction temperature is generally 400 to 900 ° C, preferably 600 to 900 ° C, more preferably 650 to 8 ° C.
00 ° C.

The reaction pressure is usually 0 to 30 kg / cm ²
G, preferably 0 to 10 kg / cm ² G.

The reaction system may be either a continuous flow system or a batch system, but a continuous flow system is preferred.

When the continuous flow system is adopted as the reaction system, the gas space velocity (G
HSV) is usually 100 to 40,000 h ^-1 , preferably 100 to 20,000 h ^-1 , more preferably 500.
˜20,000 h ⁻¹ .

The reaction system is not particularly limited and may be a fixed bed system, a moving bed system, a fluidized bed system or the like.
The form of the reactor is not particularly limited, and for example, a tubular reactor can be used.

By reacting hydrocarbons and steam with the catalyst of the present invention under the above conditions, hydrogen,
A mixture of methane, carbon monoxide and the like is obtained, which is suitably adopted for the hydrogen production process of a fuel cell, and a mixture containing 50% by volume or more of hydrogen can be obtained.

[0050]

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

Example 1 Zirconium oxychloride (ZrOCl ₂ .8H ₂ O) 1
3.08 g, ruthenium chloride (RuCl ₃ · nH ₂ O: R
1.32 g (containing 38% by weight of u) and 7.63 g of magnesium nitrate (Mg (NO ₃ ) ₂ .6H ₂ O) were dissolved in water to obtain a 40 cc aqueous solution. This solution was stirred for 1 hour or more with a stirrer to obtain an impregnating solution. At this time, the color of the impregnation liquid was red-orange, and the pH was 0.5 or less. 20 cc of this impregnating solution was used to impregnate and support 100 g of the α-alumina molded body by the pore filling method. After the supporting, it was dried at 120 ° C. for 5 hours, and further baked in air at 500 ° C. for 2 hours. Next, the remaining impregnating liquid 20 cc
Using the above, the calcined carrier was impregnated and supported, dried and calcined again in the same procedure as described above to obtain a final catalyst. The content of each element by composition analysis of the obtained catalyst was Zr: 3.7 wt%, Mg: 0.7 wt%, Ru: 0.5 wt% in terms of metal. Powder X of this catalyst
The line diffraction measurement was performed under the following conditions. The X-ray diffraction pattern is shown in FIG. Equipment: RAD-C system manufactured by Rigaku Corporation Conditions: 2θ = 25 to 60 deg Tube current, voltage: 40 kV, 40 mA (CuKα line) Step scan method Step width: 0.01 deg Sampling time: 1 sec The strongest diffraction line of α-alumina Exists at 2θ = 43.3 deg. This count number is I _A. On the other hand, the strongest peak in the diffraction lines of compounds other than α-alumina is I _S
And Ratio of the strongest diffraction line among the diffraction lines of compounds other than α-alumina to the strongest diffraction line of α-alumina I
The value of _S / I _A shown in Table 1.

The BET surface area of this catalyst was measured under the following apparatus and conditions. Device: OMNISO made by Omnicron Technology Co., Ltd.
RP 360 conditions: 5 g of a catalyst pulverized and sized to 32 mesh or more and 16 mesh or less is placed in a sample container. After installing this container in the apparatus, 0.1 torr as pretreatment
Exhaust is performed below and a treatment at 300 ° C. for 3 hours is performed. After pretreatment, N ₂ adsorption was performed up to 150 torr, and the BET surface area was determined from the amount of N ₂ adsorption on the catalyst. Table 1 shows the measurement results. The activity of the propane steam reforming reaction of this catalyst was measured by the following method.

1 cc of catalyst was filled in a quartz reaction tube having an inner diameter of 20 mm. In the reaction tube, the catalyst was passed through a hydrogen stream (H ₂ gas G
HSV: 1000 h ⁻¹ ), after reduction treatment with hydrogen at 500 ° C. for 2 hours, reaction conditions, 550 ° C. G of propane
HSV: 6000 h ^-1 , steam / carbon ratio (S /
Propane and steam were introduced under the condition of C) = 3.0 to carry out a steam reforming reaction of propane. The produced gas at this time was sampled and the produced gas concentration was measured by gas chromatography. Based on this result, the conversion of propane was determined by the following equation.

[0054]

[Equation 1] Further, after raising the reaction temperature from 550 ° C. to 800 ° C., the conversion rate of propane when the temperature was raised to 550 ° C. again was similarly obtained.

The activity ratio at 550 ° C. before and after the reaction at a high temperature of 800 ° C. was determined by the following formula.

[0056]

[Equation 2] Table 1 shows the results.

Example 2 Zirconium oxychloride (ZrOCl_Two・ 8H_TwoO) 1
3.08 g, ruthenium chloride (RuCl_Three・ NH_TwoO: R
u 38% by weight) 1.32 g, magnesium nitrate (M
g (NO_Three)_Two・ 6H_TwoO) 12.72 g and cobal nitrate
To (Co (NO_Three) _Two・ 6H_TwoO) 4.94 g dissolved in water
To give a 40 cc aqueous solution. This solution for more than 1 hour
What was stirred with a tumbler was used as the impregnating liquid. Impregnation at this time
The color of the liquid was reddish orange, and the pH was 0.5 or less.
Using 20 cc of this impregnation liquid, α-alumina molding
100 g of the body was impregnated and supported by the pore filling method. Carrying
After that, it is dried at 120 ° C for 5 hours and further at 500 ° C for 2 hours.
Firing was performed in the air. Next, the remaining impregnating liquid 20 cc
Again to the above calcined carrier using the same as above
Carry out impregnation, drying and calcination according to the procedure of
did. Content of each element by composition analysis of the obtained catalyst
In terms of metal, Zr: 3.7 wt%, MgO: 1.2
% By weight, Ru: 0.5% by weight, Co: 1.0% by weight
Was. Perform powder X-ray diffraction measurement of this catalyst under the following conditions
did. The X-ray diffraction pattern is shown in Fig. 1 and the BET surface area is shown in Table 1.
You. Evaluation of the steam reforming reaction of propane was performed in the same manner as in Example 1.
The results are shown in Table 1.

[0058] except that the Example 3 of zirconium oxychloride _{(ZrOCl 2 · 8H 2 O)} 9.16g, was 9.54g of magnesium nitrate amount was used to prepare a catalyst as in Example 2. The content of each element by the composition analysis of the obtained catalyst is Z in terms of metal.
r: 2.6% by weight, Mg: 0.9% by weight, Ru: 0.5
% By weight, Co: 1.0% by weight. The X-ray diffraction pattern and BET surface area were measured in the same manner as in Example 1. X
The line diffraction pattern is shown in FIG. 1, and the BET surface area is shown in Table 1. Evaluation of the steam reforming reaction of propane was performed in the same manner as in Example 1, and the results are shown in Table 1.

Example 4 A catalyst was prepared in the same manner as in Example 2 except that the amount of magnesium nitrate was changed to 6.36 g. The content of each element by composition analysis of the obtained catalyst was Zr: 3.7% by weight, Mg: 0.6% by weight, Ru: 0.5% by weight, Co: in terms of metal.
It was 1.0% by weight. The X-ray diffraction pattern and BET surface area were measured in the same manner as in Example 1. The X-ray diffraction pattern is shown in FIG. 1, and the BET surface area is shown in Table 1. Evaluation of the steam reforming reaction of propane was performed in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 1 A catalyst was prepared in the same manner as in Example 1 except that the amount of magnesium nitrate was 3.82 g. The content of each element by composition analysis of the obtained catalyst was Zr: 3.7 wt%, Mg: 0.4 wt%, Ru: 0.5 wt% in terms of metal. The X-ray diffraction pattern measurement and the BET surface area measurement were carried out in Example 1.
I went the same way. The X-ray diffraction pattern is shown in FIG. 1, and the BET surface area is shown in Table 1. Evaluation of the steam reforming reaction of propane was performed in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 2 A catalyst was prepared in the same manner as in Example 2 except that the amount of magnesium nitrate was changed to 3.18 g. The content of each element by composition analysis of the obtained catalyst was Zr: 3.7 wt%, Mg: 0.3 wt%, Ru: 0.5 wt%, Co: in terms of metal.
It was 1.0% by weight. The X-ray diffraction pattern and BET surface area were measured in the same manner as in Example 1. The X-ray diffraction pattern is shown in FIG. 1, and the BET surface area is shown in Table 1. Evaluation of the steam reforming reaction of propane was performed in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 3 A catalyst was prepared in the same manner as in Example 2 except that magnesium nitrate was not added. The content of each element by the composition analysis of the obtained catalyst was Zr: 3.7 wt%, R in terms of metal.
u: 0.5% by weight and Co: 1.0% by weight. The X-ray diffraction pattern and BET surface area were measured in the same manner as in Example 1. The X-ray diffraction pattern is shown in FIG. 1, and the BET surface area is shown in Table 1. Evaluation of the steam reforming reaction of propane was performed in the same manner as in Example 1, and the results are shown in Table 1.

[0063]

[Table 1]

[0064]

The ruthenium catalyst of the present invention has the ruthenium component and the cobalt component supported in the vicinity of the zirconium component in a highly dispersed state with good thermal stability, and thus has high activity and heat resistance against the steam reforming reaction of hydrocarbons. It has excellent properties and its industrial value is extremely great as a steam reforming catalyst for hydrogen production in fuel cells.

[Brief description of drawings]

FIG. 1 is an X-ray diffraction pattern of catalysts of Examples and Comparative Examples.

Claims (4)

[Claims] 1. A catalyst in which a ruthenium component, a zirconium component, and a magnesium component are contained in an α-alumina carrier, and the content of the magnesium component is 0.5 to 20 wt% in terms of magnesium metal. A steam reforming catalyst for hydrocarbons having a molar ratio of 0.5 to 5.0. 2. A catalyst comprising an α-alumina carrier containing a ruthenium component, a cobalt component, a zirconium component and a magnesium component, wherein the content of the magnesium component is 0.5 to 20% by weight in terms of magnesium metal. Mg
A catalyst for steam reforming of hydrocarbons, wherein the molar ratio of / Zr is 0.5 to 5.0. 3. The ratio I _S / I _A of the strongest peak intensity I _S of X-ray diffraction of compounds other than α-alumina to the strongest peak intensity I _A of X-ray diffraction of α-alumina is 0.01 or less. Item 1. A steam reforming catalyst for hydrocarbons according to Item 1 or 2. 4. A ruthenium component converted to ruthenium metal of 0.05 to 2% by weight, a zirconium component converted to zirconium metal of 0.005 to 15% by weight, and a magnesium component converted to magnesium metal of 0.1. The hydrocarbon steam reforming catalyst according to claim 1, which contains 5 to 20% by weight.