JP4717474B2 - Catalyst for producing hydrogen from hydrocarbon, method for producing the catalyst, and method for producing hydrogen using the catalyst - Google Patents

Description

  The present invention relates to a catalyst for producing hydrogen from a hydrocarbon, particularly a catalyst for producing hydrogen used in a fuel cell, and further relates to a method for producing hydrogen. More specifically, the present invention relates to a catalyst in which a large amount of ruthenium as an active component is supported on the outer surface of a carrier to which a predetermined amount of an alkali metal oxide is added, and a hydrogen production method using the catalyst.

Conventionally, as a method for producing hydrogen from hydrocarbons, many methods using a nickel catalyst or a ruthenium catalyst and using city gas, LPG, or a naphtha fraction as a raw material have been performed.
However, when assuming a small fuel cell power generation system for home use, light hydrocarbons such as natural gas and LPG have a high cost per calorific value, and low cost heavy hydrocarbons such as kerosene are used as raw materials from an economic viewpoint. A hydrogen production method that has been desired is desired.

  In addition, since the reforming reactor used in a small-sized fuel cell power generation system for home use needs to be downsized, the number of burners for heating the reforming catalyst bed is small and the number is small. A gradient is generated (see FIG. 2). For example, the catalyst bed outlet close to the flame coming out of the burner has a high temperature of about 650 to 850 ° C., whereas the catalyst bed inlet far from the flame coming out of the burner tends to have a low temperature of about 400 to 550 ° C. Particularly in this low temperature range, there is a problem that carbon deposition is likely to occur on the catalyst. Accordingly, a method for producing hydrogen from hydrocarbons using a catalyst that suppresses carbon deposition in the temperature range of 400 to 550 ° C. is desired.

In addition, the higher the H ₂ O / C that is one of the operating conditions, the more the carbon deposition on the catalyst can be suppressed, but the steam unit (the amount of steam used per product unit amount) increases, It is desirable to make it as low as possible.
When a steam reforming reaction is performed using a conventional nickel catalyst and a heavy hydrocarbon such as kerosene, severe carbon deposition occurs on the catalyst regardless of the reaction temperature and H ₂ O / C conditions. The problem arises that the differential pressure increases due to the clogging of the catalyst bed and the reaction cannot be continued.

On the other hand, several ruthenium-based steam reforming catalysts have been studied as catalysts with relatively little carbon deposition. Patent Document 1 (Japanese Patent Application Laid-Open No. 57-4232) discloses a catalyst obtained by adding 1% by mass or less of an alkali metal and an alkaline earth metal to an active ingredient which is ruthenium. Patent Document 2 (Japanese Patent Application Laid-Open No. 2002-126522) describes a catalyst including a catalyst active component such as ruthenium and a promoter component composed of a heat-resistant oxide, a catalyst carrier component, and the acid point of the catalyst carrier component. A hydrocarbon reforming catalyst comprising a support containing a component to be summed is disclosed. Furthermore, in Patent Document 3 (Japanese Patent Laid-Open No. 2001-276623), as a catalyst for efficiently improving the reforming activity of hydrocarbons, ruthenium as an active component is reduced to 1/3 from the outer surface of the catalyst to the center of the catalyst. In this part, a catalyst supporting 50% or more of the total amount of ruthenium supported is disclosed.
However, the conventional ruthenium catalyst cannot be expected to maintain a high activity under hydrogen production conditions using heavy raw materials such as kerosene and to suppress carbon deposition.
JP-A 57-4232 JP 2002-126522 A JP 2001-276623 A

  An object of the present invention is to provide a catalyst that significantly suppresses carbon deposition and maintains high activity even when a hydrogen production reaction using heavy hydrocarbons such as kerosene as a raw material, and a hydrogen production method using the catalyst. Is to provide.

The present inventor has paid attention to the fact that carbon deposition can be significantly suppressed by adding a predetermined amount of an alkali metal oxide to the catalyst. Also, by supporting more ruthenium, which is an active metal component, in the vicinity of the outer surface of the catalyst, the proportion of ruthenium supported inside the catalyst that does not contribute to the reaction is reduced, and as a result, the number of active points that are effective even at the same supported amount. We found that we can increase.
Further, after supporting a metal salt of ruthenium, it was converted into a hydroxide by treatment with an alkaline aqueous solution, and the active metal was highly dispersed on the support by insolubilization and fixation, thereby increasing the number of active points.
That is, in order to achieve the above object, the present invention provides a catalyst for producing hydrogen from the hydrocarbons listed in the following 1 to 9, and a method for producing hydrogen using the catalyst.
1. And (a) alumina, (b) a catalyst based on the alkali metal oxides, seen containing a 2.5 to 10 mass% in terms of oxide, the carrier containing no cerium oxide, the catalyst relative to (c) ruthenium, A catalyst for producing hydrogen by steam reforming from hydrocarbons, which is supported in an amount of 0.5 to 5% by mass in terms of metal.
2. 2. The catalyst for hydrogen production according to 1 above, wherein the alkali metal oxide of (b) is potassium oxide.
3. When ruthenium is linearly measured with EPMA (electron probe microanalyzer) in one direction so as to pass through the center of the catalyst cross section, if the distance from the catalyst outer surface to the catalyst center is r ₀ , r ₀ from the catalyst outer surface is r _0. 3. The hydrogen production catalyst according to 1 or 2 above, wherein the characteristic X-ray (Lα-ray) intensity of ruthenium detected during a distance up to / 4 is 80% or more of the total X-ray intensity.
4). 4. The hydrogen production catalyst according to any one of 1 to 3 above, wherein the ruthenium dispersity is 20% or more.
5. 5. The catalyst for hydrogen production according to any one of 1 to 4 above, which has a shape selected from a spherical shape, an elliptical spherical shape, a prismatic shape, a cylindrical shape, a hollow shape, a ring shape, and a tableting shape.
6). 6. The hydrogen production catalyst as described in any one of 1 to 5 above, wherein the starting material for potassium oxide (b) is potassium hydroxide.
7). (A) an alumina or a precursor thereof, (b) viewed contains at least one member selected from oxides and their precursors of the alkali metals, by sintering a carrier material that does not contain cerium oxide, alkali metal oxides Is prepared on the basis of catalyst, 2.5 to 10% by mass in terms of oxide, and (c) ruthenium is supported on 0.5 to 5% by mass in terms of catalyst on the basis of catalyst. 7. The method for producing a catalyst for hydrogen production according to any one of 1 to 6 above, wherein the catalyst is dried under reduced pressure at a temperature not higher than ° C., then treated with alkali, then washed with water and dried.
8). In the presence of the catalyst according to any one of 1 to 6 above, a hydrocarbon having a boiling point in the range of 130 to 350 ° C. and a hydrocarbon having a fraction of 90% by mass or more are reacted with water vapor. Manufacturing method.
9. 9. The reaction according to 8 above, wherein the reaction is performed under the conditions of a reaction temperature of 400 to 800 ° C., a reaction pressure of 0 to 0.5 MPa-G, and H ₂ O / C (molar ratio) = 2.5 to 5.0. Production method of hydrogen.

The hydrogen production catalyst of the present invention and the hydrogen production method using the same are used in the process of producing hydrogen from heavy hydrocarbons such as kerosene, under severe reaction conditions for low temperature and low H ₂ O / C catalysts. Can exhibit high carbon deposition inhibiting ability and can produce hydrogen while maintaining high activity.

  The hydrogen production catalyst of the present invention comprises at least one selected from (a) an inorganic oxide or a precursor thereof and (b) an alkali metal oxide and a precursor thereof (hereinafter simply referred to as “alkali metal or a precursor thereof”). The carrier raw material containing the carrier is referred to as “a body” and calcined at 600 to 950 ° C. to prepare an alumina composite oxide carrier, and (c) ruthenium based on the catalyst, 0.5 to 5% by mass in terms of metal. After being supported, dried, insoluble and fixed with an alkaline aqueous solution, the product is obtained by drying at 120 ° C. or lower. The catalyst is desirably used after reduction at 400 to 950 ° C. before the reaction.

(A) As an inorganic oxide, a porous thing is preferable, for example, an alumina, a silica, a silica-alumina, a titania, manganese, a zirconia, a zinc oxide etc. can be mentioned. These may be used alone or in combination of two or more. Among these, an oxide composed of alumina or a precursor thereof is preferable. In addition to ordinary alumina, an aluminum compound that forms alumina by firing at 600 to 950 ° C., such as aluminum hydroxide and aluminum nitrate, can also be used. However, it is desirable to avoid use of α-alumina or the like having an extremely small specific surface area. When alumina is used, the specific surface area is preferably 120 m ² / g or more.

(B) The purpose of using the alkali metal oxide or this precursor is to provide the catalyst of the present invention with carbon precipitation resistance, to provide steam activation ability, or to selectively support ruthenium on the outer surface of the catalyst. . That is, ruthenium, which is a catalytically active component of the present invention, is relatively excellent in the ability to suppress carbon deposition during the steam reforming reaction, but steam reforming of heavy hydrocarbons such as kerosene at low temperatures of 400 to 550 ° C. When the reaction is performed, carbon deposition cannot be suppressed.
Examples of the alkali metal oxide include Li, Na, K, Rb, Cs, and Fr oxides. Particularly, Na and K oxides are preferable, and K oxides are most preferable. Any one of these alkali metal oxides may be used alone, or two or more thereof may be used in combination. The precursor of the alkali metal oxide is not limited as long as it is a compound containing an alkali metal, but is preferably an alkali metal salt, for example, nitrate, carbonate or carbonate. In particular, with respect to the precursor of K, hydroxides, bicarbonates, and carbonates are preferable, and hydroxides are most preferable. Examples of the method for adding the alkali metal to the carrier include, but are not limited to, a kneading method and an impregnation method.

The blending ratio of the components (a) and (b) is as follows.
(B) A component is 2.5-10 mass% as a oxide on a catalyst basis, Preferably it is 2.5-7 mass%. If the component (b) is within the above range, the catalyst of the present invention can be imparted with carbon precipitation resistance, and the performance of the catalyst of the present invention can be kept stable over a long period of time. It becomes possible to highly disperse ruthenium which is an active ingredient on the top.
All the remainders may be the component (a) or may contain other components.

The shape of the carrier may be any shape other than various granular materials such as spherical, elliptical, prismatic, cylindrical, hollow, tableting, etc., and is not particularly limited, but is used for a general steam reforming reaction. The columnar and spherical particles are preferable, and the spherical shape is particularly preferable. The size of the carrier is not particularly limited, but in the case of a cylinder or a sphere, the diameter is usually 2 to 6 mm, preferably 2 to 4 mm.
A porous oxide-alkali metal oxide composite oxide support can be prepared by heating and firing such a molded product, that is, a support material, in an acidic atmosphere, for example, air, at 600 to 950 ° C. . Although baking time is not specifically limited, Usually, it is 1 to 20 hours.

The composite oxide support of alumina-alkali metal oxide thus prepared has a specific surface area of 100 m ² / g or more. The pore volume of this carrier is 0.2 to 0.7 ml / g, preferably 0.25 to 0.6 ml / g.

And (c) ruthenium is carry | supported by said support | carrier, and it becomes a catalyst for hydrogen production of this invention. The catalyst production method of the present invention will be specifically described below, but the production method of the present invention is not limited to this.
In the present invention, prior to loading ruthenium on the above-mentioned alumina-alkali metal oxide composite oxide carrier, the saturated water absorption amount of the carrier is determined. That is, the support is weighed in advance, and water is dropped into the burette to fully absorb the water into the support, and the saturated water absorption is measured. Next, a predetermined amount of ruthenium trichloride hydrate is dissolved in an amount of ion-exchanged water or distilled water equivalent to the saturated water absorption amount, and the aqueous solution is impregnated and absorbed. The temperature of the ruthenium trichloride aqueous solution at this time is preferably less than 50 ° C., particularly room temperature, in order to avoid hydrolysis of ruthenium trichloride. The impregnation time is not particularly limited, but is preferably 0.1 to 1 hour. If the time is shorter than 0.1 hour, the impregnating solution may not be distributed over the entire catalyst, resulting in non-uniformity. On the other hand, when the time is longer than 1 hour, ruthenium penetrates into the inside of the catalyst, and as a result, the ruthenium supported inside may not work as an effective active site. If the impregnation time is within this range, the impregnation liquid is spread uniformly over the entire catalyst, and a large amount of ruthenium is supported on the outer surface. Next, this is dried at a low temperature of 120 ° C. or lower. When it is dried at 120 ° C. or higher, ruthenium oxide may be generated and may be difficult to reduce in a subsequent reduction step. If it is 120 degrees C or less, a subsequent reduction | restoration process will advance easily, without producing | generating ruthenium oxide. Moreover, the drying method is not particularly limited, but vacuum drying that can be quickly dried is particularly preferable. Drying under reduced pressure not only shortens the drying time, but when the interaction between ruthenium, which is an active ingredient, and the support surface is weak, the liquid inside the catalyst moves to the evaporation interface on the outer surface of the catalyst due to capillary action as it is dried from the outer surface of the catalyst Since it moves, it becomes possible to carry | support ruthenium which is an active component on an outer surface more.

Subsequently, the carrier carrying ruthenium is dipped in an alkaline aqueous solution 3 times or more in terms of moles relative to the amount of ruthenium trichloride carried on the carrier, and the ruthenium trichloride is converted into ruthenium hydroxide as shown in the chemical formula 1. To convert ruthenium into insoluble and immobilized on the carrier. Due to such insolubilization / immobilization treatment, ruthenium trichloride chlorine is in the form of ammonium chloride, so that dechlorination can be efficiently carried out in the subsequent washing step.
Chemical formula 1: RuCl ₃ + 3NH ₄ OH → Ru (OH) ₃ + 3NH ₄ Cl
For supporting ruthenium on the support, not only the above-mentioned ruthenium trichloride hydrate, but also an aqueous solution of ruthenium trichloride anhydride, ruthenate such as potassium ruthenate, ruthenium salt such as ruthenium nitrate, etc. is used. You can also.
Also, as the aqueous alkaline solution used for insolubilization / immobilization of ruthenium, an aqueous solution of ammonium hydrogen carbonate, ammonium carbonate, sodium carbonate, sodium hydrogen carbonate, sodium hydroxide, potassium hydroxide, etc. may be used in addition to the above ammonia water. it can.

  In the present invention, the supported amount of ruthenium is 0.5 to 5% by mass, preferably 1 to 4% by mass, and more preferably 1 to 3% by mass in terms of a catalyst after reduction treatment described later, in terms of metal. If only the ruthenium dispersibility is to be improved, the loading amount may be reduced. However, the catalyst used in the steam reforming reaction using heavy hydrocarbons equivalent to naphtha or kerosene as the required level is required. Combining the number of active points and the degree of dispersion is important for maintaining the catalyst performance. Further, if the loading amount is too high, it is not economically preferable.

FIG. 1 shows the relationship between the section cut through the center of the catalyst for hydrogen production of the present invention and the characteristic X-ray (Lα-ray) intensity of ruthenium when line analysis is performed through the center of the section by the EPMA method. Shown in Particularly preferred catalysts of the present invention, when ruthenium was line analysis measured in one direction through the center of the catalyst section, and the distance from the catalyst outer surface to the catalytic center and r _0, r from the catalyst outer surface ₀ / The characteristic X-ray intensity of ruthenium detected during the distance up to 4 is 80% or more of the total X-ray intensity. Thus, by supporting more ruthenium, which is an active component, in the vicinity of the outer surface of the catalyst, the ratio of ruthenium supported inside the catalyst that does not contribute to the reaction is reduced, and as a result, effective activity is maintained even at the same supported amount. You can increase your score. Incidentally, the percentage C of ruthenium existing between r _0/4 from the outer surface of the catalyst is obtained by Equation 1 below.
Equation 1: C = [integrated value of characteristic X-ray intensities of the ruthenium present in the catalyst outer surface r _0/4 / total
Integral value of characteristic X-ray intensity of ruthenium] × 100
As an example of the present invention, FIG. 1 shows a cross-sectional view when cut in a plane parallel to the bottom surface of a cylindrical carrier.

Further, the hydrogen production catalyst of the present invention is a catalyst in which a required amount of ruthenium is supported in a highly dispersed state. That is, in the present invention, as described above, an alumina-alkali metal oxide composite oxide carrier is impregnated with a ruthenium-containing aqueous solution, and then insoluble and immobilized on the carrier with an alkaline aqueous solution. Ruthenium is supported at a dispersity of 20% or more, but as described in the examples, the required blending amount can be supported by 20 to 80%, preferably 25 to 50%.
In the present invention, the ruthenium dispersity is a ratio of the number of moles of CO adsorbed to the number of moles of ruthenium supported on the catalyst when CO is adsorbed on the catalyst, and is represented by the following formula 2.
Formula 2: Ruthenium dispersity (%) = [CO mol adsorbed on catalyst after 400 ° C. H ₂ reduction treatment]
Number / number of moles of ruthenium in the catalyst] × 100
The degree of dispersion of ruthenium is obtained by utilizing the property that CO selectively chemisorbs on ruthenium, and indicates the percentage of active sites that can participate in the actual catalytic reaction among ruthenium contained in the catalyst. It is. Therefore, if there is ruthenium hidden from the surface by sintering or evaporation to dryness, or ruthenium that cannot be exposed to the surface by condensation or the like, CO adsorption does not occur there, and the dispersity value becomes low.

  Further, after insoluble and immobilized as ruthenium hydroxide on the support, in order to suppress oxidation of this ruthenium hydroxide, prior to the reduction treatment of the catalyst of the present invention, 120 ° C. or less, preferably 90 ° C. or less, more preferably Is preferably dried at 50 ° C. or lower, under reduced pressure or normal pressure.

It makes sense to dry in a noble gas such as helium or argon, or an inert gas stream such as nitrogen. However, if it is operated at 120 ° C. or lower, the amount of oxide produced is in air. It is scarce and does not matter. In drying in the air, the lower the drying temperature, the more advantageous in terms of suppressing the formation of oxides. However, if the drying temperature is too low, the drying time becomes significantly long, which is not realistic. Therefore, the drying time may be appropriately selected according to the conditions such as the drying temperature and the amount of the object to be dried, but usually about 1 to 20 hours is preferable.
By reducing the ruthenium hydroxide on the carrier thus dried at a relatively low temperature, the ruthenium hydroxide supported uniformly (that is, in a state of high dispersion as described above) remains as it is ( That is, reduction can be performed in a state of high dispersity as described above.

  In general, a decrease in the degree of dispersion of ruthenium is caused by sintering, and this decrease in the degree of dispersion due to sintering includes at least two causes. One of them is sintering of the carrier itself. Even if the active metal is highly dispersed, if the carrier is sintered due to a change due to heat, the particle interval of the active metal is narrowed and the degree of dispersion is lowered. The other is sintering of the active metal itself. In the present invention, by selecting ruthenium having a melting point higher than the steam reforming reaction temperature and the active metal as the active metal (the melting point of the metal ruthenium is 2450 ° C.), the steam reforming reaction (endothermic reaction) can be performed. The support and the active metal can be made less susceptible to changes due to heat.

  In addition, ruthenium hydroxide insoluble and immobilized on the carrier is reduced to metal ruthenium in a low temperature range of about 60 to 80 ° C. However, in the case of an extremely fine particle active metal, a part of the active sites are heated. It is also possible to undergo changes due to. Therefore, in the present invention, the reduction temperature of the catalyst is set to 400 to 950 ° C., preferably 400 to 800 ° C., so that stable catalyst performance can be maintained for a long time. If the reduction temperature of the catalyst is within the above range, there is little reduction in the metal surface area due to the aggregation and sintering of ruthenium, and further, there is no blockage of the pores of the support or the transition to the α phase of alumina. The catalytic activity can be maintained. As the reducing gas, hydrogen gas, hydrogen / water vapor mixed gas, carbon monoxide, or the like can be used. Among these, hydrogen gas and hydrogen / water vapor mixed gas are preferable, and hydrogen gas is particularly preferable. The reduction time may be appropriately selected according to conditions such as the reduction temperature and the amount of the reducing gas flow, but about 1 to 20 hours is practical.

  As described above, the hydrogen production catalyst of the present invention is a catalyst in which a large amount of ruthenium as an active component is present on the outer surface of the catalyst, and the ruthenium dispersity is as high as 20% or more.

In the method for producing hydrogen in the presence of the hydrogen production catalyst of the present invention described in detail above, the raw material has a sulfur content of 0.1 mass ppm or less, a carbon number of 1 or more, and a distillation range at atmospheric pressure of 350 ° C. The following hydrocarbons are preferably used, and hydrocarbons having a fraction having a boiling point range of 130 to 350 ° C. of 90% by mass or more are more preferably used, and a kerosene fraction can be particularly preferably used. At this time, the reaction pressure is 0 to 5 MPa-G, H ₂ O / C = 2.5 to 5, and the reaction temperature is not particularly limited, but 400 to 800 ° C. is suitable. The reaction method is not particularly limited, but a batch type, semi-continuous type or continuous type operation using a fixed bed or moving bed reactor is preferable.
In the hydrogen production method of the present invention, the hydrogen production catalyst of the present invention may be used alone or in combination with a catalyst other than the catalyst of the present invention.

  Further, hydrogen can be produced by filling the catalyst for producing hydrogen of the present invention in a part of an oxygen variable autothermal reforming (ATR) reactor. The ATR reaction is characterized by the fact that an oxidation reaction mainly occurs at the reactor inlet and heat is generated. However, heat generation due to the oxidation reaction hardly occurs in the deep part of the reactor, and a steam reforming reaction mainly occurs. In this case, the ATR catalyst suitable for the oxidation reaction can be filled in the former stage and the hydrogen production catalyst of the present invention can be filled in the latter stage.

In the following examples, the generated gas analysis is performed by filling a stainless steel (SUS) tube (inner diameter: 3 mm, length: 2 m) with a 60-80 mesh filler (Unibeads-C, manufactured by GL Sciences) and separating it. H ₂ , CO, CO ₂ , and CH ₄ were measured with a gas chromatograph (GC-390, manufactured by GL Science) with a thermal conductivity detector (TCD) attached as a column.
In addition, the analysis of C _{1 to} C ₅ in the product gas was performed on a gas chromatograph (GC-390, manufactured by GL Science) with a flame ionization detector (FID) equipped with a capillary column of Al ₂ O ₃ / KCl as a separation column. I went. The amount of metal supported on the catalyst was confirmed by inductively coupled plasma emission analysis (ICP analysis). The amount of carbon deposited on the catalyst was measured with an infrared detection type carbon analyzer (ModelEMIA-810, manufactured by Horiba, Ltd.).

  The amount of CO adsorbed on the catalyst was measured by an automatic adsorption device (R6015, manufactured by Okura Riken) with a built-in TCD gas chromatograph. The CO adsorption amount is measured by putting a catalyst in a sample tube, using He gas as a carrier gas, using hydrogen as a reducing gas, first flowing hydrogen gas and raising the temperature in one hour to 400 ° C., which is the reduction temperature. Then, reduction was performed at 400 ° C. for 1 hour. Subsequently, the gas was switched to He gas and cooled to 50 ° C., and then a certain amount of CO gas was flowed through the sample tube to measure the CO adsorption amount.

The line analysis measurement performed on ruthenium in one direction so as to pass through the center of the catalyst was performed using an electron probe microanalyzer (EPMA manufactured by JEOL Ltd., JXA-8600MX). The measurement conditions were an acceleration voltage of 20 kV, an incident current of 1 × 10 ⁻⁷ A, an interval between measurement points of 10 μm, and a counting time of 0.5 sec. The cross section of the measurement catalyst was prepared by embedding the catalyst in MMA (methyl methacrylate) and polishing it using a polishing apparatus. Then, in accordance with the above equation 1, when the distance between the center and the r ₀ from the outer surface of the catalyst was determined the percentage C of ruthenium present from the outer surface of the catalyst during the 1 / 4r _0.

The conversion rate of the raw material C ₁ was obtained from the following formula 3.
Formula 3: Raw material C ₁ conversion (%) = [M / M ₀ ] × 100
In the formula, M ₀ is the number of carbon moles of the feed hydrocarbon per unit time, and M is the number of carbon moles of the C ₁ compound (CO, CO ₂ , CH ₄ ) in the product gas per unit time.

Example 1
Alumina powder (200 mesh) is formed into a spherical shape (spherical pellet) with a molding pressure of 2000 MPa (20 tons / cm ² ) and a diameter of 3.2 mm using a tableting molding machine (FK-1 type, manufactured by Systems Engineering). Molding and firing in a muffle furnace in air at 600 ° C. for 3 hours gave alumina oxide. The composite oxide had a specific surface area of 140 m ² / g and a pore volume of 0.43 ml / g.
Next, 3.63 g of potassium hydroxide was dissolved in 19.3 g of ion-exchanged water, dropped into 35.0 g of alumina oxide, stirred so that the aqueous potassium nitrate solution was uniform over the entire support, and allowed to stand for 1 hour. Dried. Subsequently, it baked at 600 degreeC in the air in the muffle furnace for 3 hours, and obtained alumina-potassium oxide complex oxide. The composite oxide had a specific surface area of 132 m ² / g and a pore volume of 0.34 ml / g.

Ruthenium trichloride hydrate (RuCl ₃ · nH ₂ O, ruthenium content 39 mass%) 1.81 g was dissolved in 11.1 g of water, and this aqueous solution was dropped into 30 g of the above-mentioned alumina-potassium oxide composite oxide. And left at room temperature for 1 hour. Subsequently, the spherical pellets were heated to 50 ° C. with an infrared hot plate under a vacuum of about 2.7 kPa (about 20 mmHg) by a rotary evaporator and dried.
Next, the spherical pellet was transferred into about 1 L of 7 mol / L aqueous ammonia (diluted about twice as high as a commercially available reagent special grade), and stirred slowly with a stirrer for 1 hour to insolubilize and fix ruthenium. The spherical pellet was recovered from the aqueous ammonia using a Buchner funnel. The collected spherical pellets were thoroughly washed with ion exchange water. At the end of washing, an aqueous silver nitrate solution was dropped into a part of the filtrate, and the white precipitate of silver chloride was not generated. The washed spherical pellets were dried in a dryer at 50 ° C. for 15 hours to obtain Catalyst A. Catalyst A is composed of 1.8% by mass of ruthenium (converted to metal), 2.9% by mass of potassium oxide (converted to oxide), and the remaining alumina. Table 1 shows the physical properties of Catalyst A.
The reactor was charged with 7.5 ml of catalyst A, and reduced with hydrogen whose flow rate was adjusted with a mass flow controller at 0.005 MPa-G, 450 ° C., GHSV = 400 (v / v) h ⁻¹ for 1 hour. Subsequently, desulfurized kerosene listed in Table 4 was introduced into the reactor as raw material oil together with steam, and the steam reforming reaction was performed at a reaction temperature of 450 ° C., 0.005 MPa-G, H ₂ O / C = 3.5, The test was performed under the condition of LHSV = 0.83 (v / v) h ⁻¹ . The reaction results are shown in Table 1.

Example 2
The reactor was charged with 7.5 ml of the same catalyst A as in Example 1, and reduced with hydrogen whose flow rate was adjusted with a mass flow controller at 0.005 MPa-G, 450 ° C., GHSV = 400 (v / v) h ⁻¹ for 1 hour. did. Subsequently, the desulfurized naphtha shown in Table 5 was introduced into the reactor together with steam, and the steam reforming reaction was performed at a reaction temperature of 450 ° C., 0.005 MPa-G, H ₂ O / C = 3.5, LHSV = 0. It was performed under the condition of 83 (v / v) h ⁻¹ . The reaction results are shown in Table 1.

Example 3
The reactor was charged with 7.5 ml of the same catalyst A as in Example 1, and reduced with hydrogen whose flow rate was adjusted with a mass flow controller at 0.005 MPa-G, 600 ° C., GHSV = 400 (v / v) h ⁻¹ for 1 hour. did. Subsequently, desulfurized kerosene described in Table 4 was introduced into the reactor as raw material oil together with steam, and the steam reforming reaction was performed at a reaction temperature of 450 ° C., 0.005 MPa-G, H ₂ O / C = 3.0, The test was performed under the condition of LHSV = 3 (v / v) h ⁻¹ . The reaction results are shown in Table 1.

Reference example 1
The catalyst B prepared in the same manner as in Example 1 was evaluated in the same manner as in Example 3 except that potassium hydroxide was replaced with potassium nitrate, the supported amount was 6.54 g, and ion-exchanged water 19.3 g. The results are shown in Table 1.

Example 5
Catalyst C prepared in the same manner as in Example 1 was evaluated in the same manner as in Example 3 except that potassium hydroxide was replaced with potassium bicarbonate, the loading was 6.48 g, and ion-exchanged water was 19.3 g. The results are shown in Table 1.

Example 6
The catalyst D prepared in the same manner as in Example 1 was evaluated in the same manner as in Example 3 except that potassium hydroxide was replaced with potassium carbonate, the supported amount was 4.47 g, and ion-exchanged water 19.3 g. The results are shown in Table 1.

Reference example 2
Catalyst E prepared in the same manner as in Example 1 was evaluated in the same manner as in Example 3 except that the K source in Example 1 was loaded with 6.54 g of potassium nitrate and 5.79 g of ruthenium trichloride hydrate. The results are shown in Table 1.

Reference example 3
Example 1 except that the alumina of Example 1 is molded into a spherical shape (spherical pellet) and then calcined in a muffle furnace at 800 ° C., and the alumina-potassium oxide composite oxide is calcined at 800 ° C. in a muffle furnace. Catalyst F prepared in the same manner as in Example 1 was evaluated in the same manner as in Example 3. The results are shown in Table 1.

Comparative Example 1
An alumina-potassium oxide composite oxide was obtained in the same manner as in Example 1 except that the amount of potassium nitrate was 2.62 g.
Next, in the same manner as in Example 1, ruthenium support and alkali treatment were performed, and Catalyst G was obtained. The catalyst G is composed of ruthenium 2.2% by mass (metal conversion), potassium oxide 0.9% by mass (oxide conversion), the remainder and alumina. Table 2 shows the physical properties of the catalyst G.
Reduction and reaction were performed in the same manner as in Example 1 except that the catalyst G was used. The reaction results are shown in Table 2.

  The hydrogen production catalyst of the present invention can also be used as a part of ATR. The following is an example.

Reference example 4
Alumina powder (200 mesh) is used in the first stage, and a cylindrical shape (circle) with a molding pressure of 2000 MPa (20 tons / cm ² ) using a tableting molding machine (FK-1 type, manufactured by Systems Engineering Co., Ltd.). Columnar pellets) and fired in a muffle furnace in air at 900 ° C. for 3 hours to obtain an alumina molded body. A solution prepared by dissolving 0.14 g of rhodium nitrate having a purity of 99.5% or more in 3.8 cc of ion-exchanged water is supported on 10 g of the above-mentioned alumina molded body, and stirred so that the aqueous rhodium nitrate solution is uniform over the entire support. And left for 1 hour. Subsequently, the pellets were dried by heating at 50 ° C. with an infrared hot plate under a vacuum of about 2.7 kPa (about 20 mmHg) by a rotary evaporator.
The dried pellets were calcined in a muffle furnace for 4 hours to prepare a catalyst of 0.5 mass% Rh and the remaining alumina, and 4 cc of this catalyst was filled in the previous stage.
In the middle, 12 cc of Catalyst A was charged.
Further, alumina powder (200 mesh) is formed into a cylindrical pellet having a diameter of 3.2 mm at a molding pressure of 2000 MPa (20 ton / cm ² ) using a tableting molding machine (FK-1 type, manufactured by Systems Engineering). An alumina molded body that was molded and fired at 800 ° C. for 3 hours in air in a muffle furnace was obtained. Ruthenium trichloride hydrate (RuCl ₃ · nH ₂ O, ruthenium content 39% by mass) 0.387 g and ion-exchanged water 11.4 g are supported on 30 g of the above-mentioned alumina molded body, and the aqueous ruthenium chloride solution is uniform throughout the support. After stirring, the mixture was allowed to stand for 1 hour. Subsequently, the cylindrical pellet was dried by heating at 50 ° C. with an infrared hot plate under a vacuum of about 2.7 kPa (about 20 mmHg) using a rotary evaporator. Next, the pellet was transferred into about 1 L of 7 mol / L aqueous ammonia (diluted about twice as much as a special grade of commercially available reagent) and slowly stirred with a stirrer for 1 hour to insolubilize and fix ruthenium. This cylindrical pellet was recovered from the aqueous ammonia using a Buchner funnel. The collected pellets were thoroughly washed with ion exchange water. At the end of washing, an aqueous silver nitrate solution was dropped into a part of the filtrate, and the white precipitate of silver chloride was not generated. The washed cylindrical pellet was dried in a dryer at 50 ° C. for 15 hours to obtain a catalyst composed of 0.5% by mass of ruthenium (metal conversion) and the remaining alumina. 12 cc of this catalyst was charged in the latter stage.
Using this reactor, oxygen / carbon (mol / mol) = 0.1, LHSV (vol / vol) = 0.24, H ₂ O / carbon (mol / mol) = 3 reactor front stage temperature 450 ° C., middle stage temperature 486 The evaluation was performed at 0 ° C. and the rear stage temperature of 680 ° C. These results are shown in Table 3.

Reference Example 5
Evaluation was performed in the same manner as in Reference Example 4 except that LHSV (vol / vol) = 0.48, reactor front stage temperature 470 ° C., middle stage temperature 494 ° C., and rear stage temperature 680 ° C. The results are shown in Table 3.

Reference Example 6
Evaluation was performed in the same manner as in Reference Example 4 except that LHSV (vol / vol) = 0.71, reactor front stage temperature 471 ° C., middle stage temperature 485 ° C., and rear stage temperature 680 ° C. The results are shown in Table 3.

As is clear from Examples 1-3, 5 and 6 , by using a catalyst in which 0.5 to 5% by mass of ruthenium is supported on an alumina composite oxide support containing an alkali metal oxide, desulfurized kerosene or the like is used. Even in the steam reforming reaction using a high quality hydrocarbon as a raw material, carbon precipitation can be effectively suppressed and a high raw material C ₁ conversion can be obtained. Also it is possible to lower high filled partially oxygen region ATR reaction in the material C ₁ conversion rate obtained.
On the other hand, as is clear from Comparative Example 1, when the amount of alkali metal oxide (K ₂ O) supported in the catalyst is as small as 0.9% by mass, carbon deposition as a side reaction can be effectively suppressed. Cannot be obtained, and high activity cannot be obtained.

The figure which shows the relationship with the characteristic X-ray (L alpha ray) intensity | strength of the cross section cut through the center of the catalyst for hydrogen production of this invention, and the ruthenium when carrying out a line analysis so that it may pass along the center of a cross section by EPMA method It is. It is a schematic cross section of the reforming reactor used for the small-sized sample battery power generation system for home use.

Claims (9)

And (a) alumina, (b) a catalyst based on the alkali metal oxides, seen containing a 2.5 to 10 mass% in terms of oxide, the carrier containing no cerium oxide, the catalyst relative to (c) ruthenium, A catalyst for producing hydrogen by steam reforming from hydrocarbons, which is supported in an amount of 0.5 to 5% by mass in terms of metal.   2. The hydrogen production catalyst according to claim 1, wherein the alkali metal oxide of (b) is potassium oxide. When ruthenium is linearly measured with EPMA (electron probe microanalyzer) in one direction so as to pass through the center of the catalyst cross section, if the distance from the catalyst outer surface to the catalyst center is r ₀ , r ₀ from the catalyst outer surface is r _0. The catalyst for hydrogen production according to claim 1 or 2, wherein the characteristic X-ray (Lα ray) intensity of ruthenium detected during a distance up to / 4 is 80% or more of the total X-ray intensity.   The catalyst for hydrogen production according to any one of claims 1 to 3, wherein the ruthenium dispersity is 20% or more.   The catalyst for hydrogen production according to any one of claims 1 to 4, which has a shape selected from a spherical shape, an elliptical spherical shape, a prismatic shape, a cylindrical shape, a hollow shape, a ring shape, and a tableting shape.   The catalyst for hydrogen production according to any one of claims 1 to 5, wherein the starting material of potassium oxide (b) is potassium hydroxide. (A) an alumina or a precursor thereof, (b) viewed contains at least one member selected from oxides and their precursors of the alkali metals, by sintering a carrier material that does not contain cerium oxide, alkali metal oxides Is prepared on the basis of catalyst, 2.5 to 10% by mass in terms of oxide, and (c) ruthenium is supported on 0.5 to 5% by mass in terms of catalyst on the basis of catalyst. The method for producing a catalyst for hydrogen production according to any one of claims 1 to 6, wherein the catalyst is dried under reduced pressure at a temperature not higher than ° C, then treated with alkali, then washed with water and dried.   Hydrogen, characterized in that, in the presence of the catalyst according to any one of claims 1 to 6, a hydrocarbon having a boiling point in the range of 130 to 350 ° C is reacted with water vapor and a hydrocarbon having a fraction of 90 mass% or more. Manufacturing method. 9. The reaction is performed under the conditions of a reaction temperature of 400 to 800 ° C., a reaction pressure of 0 to 0.5 MPa-G, and H ₂ O / C (molar ratio) = 2.5 to 5.0. Of hydrogen production.