JP5354142B2 - Steam reforming catalyst and reaction gas production method - Google Patents

Description

  The present invention relates to a catalyst carrier that is excellent in sulfur poisoning resistance and that can be industrially produced in large quantities, a steam reforming catalyst using the carrier, and a sulfur-containing hydrocarbon steam using the catalyst. It aims at providing the manufacturing method of the mixed gas of C1 component and hydrogen by reforming reaction.

  The current situation of biasing to coal and oil as an energy source using a large power generation device is easily affected by natural disasters such as earthquakes, rising raw material prices, terrorism and war. Screamed.

  Rather than generating electrical energy at a power plant and allocating it to households and business establishments via transmission lines and wires, generating electricity with a cogeneration system in a place where electricity is required is more energy efficient. Since the generation amount of carbon and the like can be reduced, there are great expectations in terms of the global environment and the depletion of resources. Of these, the most promising is power generation by a fuel cell system using hydrogen, which is being put into practical use in recent years.

  A wide variety of hydrocarbon raw materials, such as petroleum, such as kerosene, isooctane, and gasoline, LP gas, and city gas, are being studied as a source of hydrogen generated in fuel cells.

  However, petroleum-based raw materials and LP gas contain sulfur in the raw material itself, and city gas contains sulfur in a total sulfur content of approximately 10 ppm to 100 ppm or more by post-addition.

  When reforming a hydrocarbon feedstock to a hydrogen-rich mixed gas, a large amount of sulfur in the hydrocarbon feedstock poisons the reformer catalyst in the fuel cell system and degrades the catalytic activity. A desulfurization catalyst and an expensive desulfurization system must be installed upstream of the fuel cell system. As a result, the cost of the entire system is greatly increased, which is one of the factors that obstruct the spread of fuel cell systems in the future.

  Therefore, studies are underway to reduce the cost by using a catalyst body with high sulfur poisoning resistance. Giving sulfur-resistant poisoning to the catalytically active metal itself is mainly carried out by improving the carrier for supporting the catalytically active metal (Patent Documents 1 to 4). Moreover, what contains magnesium and aluminum as a steam reforming catalyst of hydrocarbon is known (patent documents 5 and 6).

JP-A-9-173842 JP 2001-340759 A JP 2004-900 A JP 2004-82034 A Japanese Patent Application Laid-Open No. 55-139836 Japanese Patent Application Laid-Open No. 2003-225566

  Although the techniques described in Patent Documents 1 to 4 improve sulfur poisoning resistance, they are still not sufficient. Patent Documents 5 and 6 do not consider sulfur poisoning resistance.

  In particular, since the steam reforming reaction for obtaining hydrogen is performed at a high reaction field temperature of 600 ° C. or higher, sintering of the support main component such as aluminum or zirconium is promoted in the steam reaction, so that the support itself Not only are the pores and specific surface area reduced, the activity of the active species metal is impaired, but also the sintering of the active species metal is promoted at the same time. There is a big problem with sex.

  Although there is a demand for a porous carrier that does not sinter and imparts high-performance sulfur poisoning resistance to the catalyst, a catalyst body having sufficient effects, performance, and durability has not been obtained.

  The technical problem can be achieved by the present invention as follows.

That is, the present invention is a composite oxide composed of at least aluminum and magnesium, has a BET specific surface area of 10 to 300 m ² / g, an average pore diameter of 300 mm or less, and a pore volume of 0. 1. A porous carrier for a steam reforming catalyst, characterized by being 1 cm ³ / g or more (Invention 1).

  The present invention also provides the porous carrier and oxidation of at least one element selected from rare earth elements including silicon, zirconium, cerium, titanium, aluminum, yttrium and scandium, group Ia elements and group IIa elements. A porous support for a steam reforming catalyst, characterized in that the Mg content of the mixture is 20 to 50 wt% in terms of Mg It is a mixture (Invention 2).

  In the present invention, the porous carrier or the mixture of the porous carriers is a kind selected from Ru, Rh, Ir, Pt, Pd, Co, Ni, Fe, and Ag having an average particle diameter of 1 to 15 nm or A steam reforming catalyst characterized by supporting two or more active species metals (Invention 3).

  Further, the present invention provides a reaction mixed gas characterized in that a gaseous mixture or a liquid hydrocarbon raw material is decomposed using the steam reforming catalyst to obtain a reaction mixed gas mainly composed of a C1 component and hydrogen. It is a manufacturing method. (Invention 4).

The porous carrier and the steam reforming catalyst according to the present invention can suppress the sintering of the porous carrier and the active species metal, and maintain high sulfur catalytic resistance as well as high-performance catalytic activity over a long period of time. it can.
Therefore, in this invention, even if it is a hydrocarbon raw material containing a trace amount sulfur, steam reforming can be performed efficiently and the mixed gas of C1 component and hydrogen can be manufactured.

  First, the porous carrier for the steam reforming catalyst according to the present invention will be described.

The BET specific surface area of the porous carrier for a steam reforming catalyst according to the present invention is 10 to 300 m ² / g. When the BET specific surface area is less than 10 m ² / g, the average pore diameter becomes large and sintering of the active species metal to be supported cannot be sufficiently suppressed. Those exceeding 300 m ² / g are not realistic because they cannot be industrially produced. Preferably it is 20-280 m < ² > / g, More preferably, it is 23-270 m < ² > / g.

  The average pore diameter of the porous carrier for the steam reforming catalyst according to the present invention is 300 mm or less. When the average pore diameter exceeds 300 mm, not only the sintering of the active species metal cannot be sufficiently suppressed but also the characteristic of sulfur poisoning resistance cannot be exhibited sufficiently. Preferably it is 290 mm or less, more preferably 280 mm or less. The lower limit is about 10 mm.

The pore volume of the porous carrier for the steam reforming catalyst according to the present invention is 0.1 cm ³ / g or more. When it is less than 0.1 cm ³ / g, not only a sufficient catalytic activity cannot be obtained, but also the characteristics of sulfur poisoning resistance cannot be exhibited sufficiently. Preferably it is 0.12 cm ³ / g. The upper limit is about 5 cm ³ / g.

  The porous carrier of the steam reforming catalyst according to the first aspect of the present invention may be a powder, or a molded body such as a bead or a sheet.

When the porous carrier of the steam reforming catalyst according to the present invention is a molded body, the BET specific surface area is preferably 10 to 100 m ² / g. When the BET specific surface area is less than 10 m ² / g, it is difficult not only to reduce the catalytic activity but also to exhibit excellent sulfur poisoning resistance. Those exceeding 100 m ² / g are not realistic because the molding strength decreases. More preferably, it is 10-98 m < ² > / g, More preferably, it is 11-95 m < ² > / g.

  In the case of the molded body of the porous carrier of the steam reforming catalyst according to the present invention, the average pore diameter is preferably 250 mm or less. When the average pore diameter exceeds 250 mm, sintering of the active species metal cannot be sufficiently suppressed. More preferably, it is 245 mm or less, and still more preferably 240 mm or less. The lower limit is about 10 mm.

In the case of the molded body of the porous carrier of the steam reforming catalyst according to the present invention, the pore volume is preferably 0.1 cm ³ / g or more. When the pore volume is less than 0.1 cm ³ / g, it is difficult to obtain sufficient catalytic activity, and the characteristics of sulfur poisoning resistance cannot be exhibited sufficiently. More preferably, it is 0.12 cm ³ / g or more. The upper limit is about 5 cm ³ / g.

  The bead-like or sheet-like porous carrier may be produced only from the above porous carrier, or may be applied to a base material such as cordierite or alumina having a desired size, form and shape.

The magnesium content in the composite oxide constituting the porous carrier of the present invention is 22 to 60 wt%, preferably 23 to 55 wt% in terms of Mg with respect to the weight of the porous carrier, and the aluminum content is porous. 5 to 30 wt%, preferably 7.5 to 25 wt% in terms of Al with respect to the weight of the carrier (however, in the case of a shaped porous carrier, base materials such as cordierite and alumina are excluded from the weight) .
When the magnesium content is less than 22 wt% in terms of Mg with respect to the weight of the porous carrier, it is difficult to exhibit sufficient sulfur poisoning resistance. Even if magnesium exceeds 60 wt%, the effect of sulfur poisoning resistance is not improved.
The molar ratio (Mg: Al) of magnesium element to aluminum element of the composite oxide itself constituting the porous simple substance is 1.2: 1 to 5: 1, preferably 1.5: 1 to 4.8. is there.

  In the present invention, the porous support according to the present invention 1 or a molded body thereof is selected from rare earth elements including silicon, zirconium, cerium, titanium, aluminum, yttrium and scandium, group Ia elements and group IIa elements. An oxide, hydroxide, carbonate, or hydrated oxide of at least one element may be mixed.

  Examples of the oxide, hydroxide, carbonate or hydrated oxide of the element include silica, zirconia, ceria, titania, water glass, yttria, scandia, potassium carbonate, calcia, lanthanum oxide, neodymium oxide, cerium oxide, and hydroxide. Rubidium, barium carbonate, boehmite, α-alumina, θ-alumina, γ-alumina and the like, and one or more of these compounds.

  The particle shape of the oxide, hydroxide, carbonate or hydrated oxide of the element may be any shape such as granular, fibrous, needle-shaped, or spindle-shaped.

The mixture of the porous support | carrier of the catalyst for steam reforming which concerns on this invention 2 contains Mg content 20.0-50.0 wt% with respect to the whole in conversion of Mg. If it is less than 20.0 wt%, sufficient sulfur poisoning resistance cannot be exhibited. Even if magnesium exceeds 50.0 wt%, the effect of sulfur poisoning resistance is not improved. Preferably it is 21.0-49.0 wt%, More preferably, it is 22.0-48.0 wt%.
Moreover, aluminum content is 3-30 wt% with respect to the whole in conversion of Al, Preferably it is 4-28 wt%.
In these cases, the base material such as cordierite and alumina is excluded from the weight in the case of the molded porous carrier.

  The steam reforming catalyst according to the present invention 3 is high by supporting the active species metal in a size within a range of 1 to 15 nm on the porous support of the present invention 1 or the mixture of the porous support of the present invention 2. It is a catalyst that can maintain the catalytic activity for a long time.

  The active species metal may be at least one selected from Ru, Rh, Ir, Pt, Pd, Co, Ni, Fe, Ag, and the like.

  The average particle size of the active species metal is preferably 1 to 20 nm. When the average particle diameter exceeds 20 nm, catalyst activity may be reduced or coking may occur. More preferably, it is 1.5-15 nm.

  The steam reforming catalyst according to the present invention 3 is high by supporting the active species metal in a size within a range of 1 to 15 nm on the porous support of the present invention 1 or the mixture of the porous support of the present invention 2. It is a catalyst that can maintain the catalytic activity for a long time.

  The supported amount of the active species metal in the steam reforming catalyst according to the present invention 3 is preferably 0.1 to 40 wt%, more preferably 0.5 to 30 wt%.

The magnesium content of the steam reforming catalyst according to the present invention 3 is preferably 20 to 55 wt% in terms of Mg, and the aluminum content is preferably 7 to 25 wt% in terms of Al.
The molar ratio (Mg: Al) of magnesium and aluminum in the steam reforming catalyst according to the present invention 3 is preferably 1.2: 1 to 5: 1.

  Next, a method for producing a porous carrier according to the present invention 1 will be described.

  The porous carrier according to the present invention is a hydrated double hydroxide obtained by mixing at least an aluminum raw material and a magnesium raw material and precipitated at a pH of 8 or higher, or a hydrated double hydroxide and an aluminum compound and / or a magnesium compound. Is obtained by heat treatment at 350 to 1250 ° C.

  As the aluminum raw material, sulfates, nitrates, chloride salts, hydroxides, oxides, oxyhydroxides, alkoxide compounds, complexes of citric acid, and the like can be used.

  As the magnesium raw material, sulfates, nitrates, chloride salts, hydroxides, oxides, carbonates, alkoxide compounds, complexes of citric acid, and the like can be used.

  The pH in the reaction solution is adjusted to 8 or more, more preferably 8.5 to 14. In order to adjust pH, ammonia, urea, or hydroxides, carbonates, oxides, or the like of alkali metal elements or alkaline earth metal elements such as magnesium, potassium, and sodium can be used.

The temperature for precipitation is 10 to 300 ° C, preferably 15 to 280 ° C, more preferably 20 to 250 ° C. If it exceeds 300 ° C., industrial production becomes difficult. A temperature lower than 10 ° C. requires a cooling device, which causes a cost problem.
When the heat treatment temperature exceeds 1250 ° C., the pore diameter increases, the pore volume decreases, and the BET specific surface area also decreases, resulting in a decrease in the activity of the catalyst and a decrease in the effect of sulfur poisoning resistance. When it is lower than 350 ° C., it does not become a porous carrier. Preferably it is 370-1230 degreeC, More preferably, it is 400-1210 degreeC.

  In addition, when producing a molded body, it may be produced according to a conventional method. For example, it is applied to a cordierite honeycomb body, an alumina plate, a stainless steel metal plate, or a bead by a compression molding machine or an extrusion molding machine. A method for producing a shaped molded body may be used.

  The porous carrier mixture of the present invention 2 may be prepared by mixing a porous carrier or a molded product thereof with silica, boehmite or the like according to a conventional method. Further, it may be formed after mixing the porous carrier of the present invention with silica, boehmite or the like.

  In the present invention, a porous carrier and an oxide or hydroxide of at least one element selected from rare earth elements including silicon, zirconium, cerium, titanium, aluminum, yttrium and scandium, group Ia elements and group IIa elements The mixing ratio of the product, carbonate or hydrated oxide is preferably 0.1 to 30 wt% with respect to the porous carrier. More preferably, it is 0.5-28 wt%, and Mg content of the obtained mixture is 20-50 wt% in terms of Mg.

The steam reforming catalyst according to the present invention 3 is one in which an active species metal is supported on the porous carrier or a mixture of porous carriers. The method for supporting the active species metal may be performed according to a conventional method.
For example, a method of immersing the porous carrier in an aqueous solution containing a salt of a desired active species metal, impregnating the active species metal, drying and heat treatment, on a cordierite honeycomb body or alumina plate, a stainless steel metal plate For example, a method of producing a bead-shaped molded body by coating on top or a compression molding machine or an extrusion molding machine.

  Next, a method for producing a reaction gas mixture using the steam reforming catalyst according to the present invention 3 will be described (present invention 4).

The step of decomposing a hydrocarbon raw material using the steam reforming catalyst according to the present invention to obtain a reaction mixed gas mainly composed of C1 component and hydrogen is a process for producing a gaseous hydrocarbon raw material having a total sulfur content of 50 ppm or less. In this case, GHSV is 100 to 1,000,000 h ⁻¹ , the reaction temperature is 300 to 800 ° C., and S / C is 1.0 to 6.0.

  Gaseous hydrocarbon raw materials are a wide variety of hydrocarbon compounds such as methane, ethane, vaporized propane, isooctane, kerosene, and gasoline.

  Examples of the sulfur-containing compound contained in the hydrocarbon raw material include methyl mercaptan, ethyl mercaptan, isobutyl mercaptan, metaethyl sulfide, dimethyl sulfide, tertiary butyl mercaptan, sec-butyl mercaptan, n-butyl mercaptan, isopropyl mercaptan. N-propyl mercaptan, isoamyl mercaptan, n-amyl mercaptan, α-methylbutyl mercaptan, α-ethylpropyl mercaptan, n-hexyl mercaptan, 2-methylcaptohexane, 3-mercaptohexane, and the like.

When GHSV is lower than 100 h ^{−1, the} obtained C1 component and hydrogen are too small, which is not practical. When GHSV exceeds 1,000,000 h ⁻¹ , a sufficient heat source cannot be provided for the endotherm caused by the reaction. Preferably it is 150-800,000h < ^-1 >, More preferably, it is 200-500,000h- ¹ .

  When the reaction temperature is below 300 ° C., the conversion to the C1 component and hydrogen hardly proceeds. If it exceeds 800 ° C., the material of the catalyst reactor becomes an expensive material such as Inconel, which is not realistic. Preferably it is 300-780 degreeC, More preferably, it is 320-750 degreeC.

  When S / C is lower than 1.0, the decomposition of the hydrocarbon itself proceeds and coking and carbon deposition progress greatly. If the S / C exceeds 6.0, the C1 component and hydrogen fraction obtained are low and not realistic. Preferably it is 1.5-4.0.

The process of decomposing a hydrocarbon raw material using the steam reforming catalyst according to the present invention to obtain a reaction mixed gas mainly composed of C1 component and hydrogen is a liquid hydrocarbon raw material having a total sulfur content of 50 ppm or less. , LHSV is 5 h ⁻¹ or less, the reaction temperature is 300 to 800 ° C., and S / C is 1.0 to 6.0.

  Liquid hydrocarbon raw materials are a wide variety of hydrocarbon compounds such as propane, isooctane, kerosene, and gasoline.

  Examples of the sulfur-containing compound contained in the hydrocarbon raw material include methyl mercaptan, ethyl mercaptan, isobutyl mercaptan, metaethyl sulfide, dimethyl sulfide, tertiary butyl mercaptan, sec-butyl mercaptan, n-butyl mercaptan, isopropyl mercaptan. N-propyl mercaptan, isoamyl mercaptan, n-amyl mercaptan, α-methylbutyl mercaptan, α-ethylpropyl mercaptan, n-hexyl mercaptan, 2-methylcaptohexane, 3-mercaptohexane, and the like.

If the LHSV exceeds 5h- ¹ , the active species metal and the hydrocarbon raw material cannot be sufficiently contacted. More preferably, it is 1-4h- ¹ .

  When the reaction temperature is below 300 ° C., the conversion to the C1 component and hydrogen hardly proceeds. If it exceeds 800 ° C., the material of the catalyst reactor becomes an expensive material such as Inconel, which is not realistic. Preferably it is 310-800 degreeC, More preferably, it is 320-800 degreeC.

  When S / C is lower than 1.0, the decomposition of the hydrocarbon itself proceeds and coking and carbon deposition progress greatly. If the S / C exceeds 6.0, the C1 component and hydrogen fraction obtained are low and not realistic. More preferably, it is 1.5-5.5.

<Action>
The reason why the porous support for catalyst for steam reforming the hydrocarbon raw material according to the present invention is excellent in sulfur poisoning resistance is not yet clear, but the present inventor estimates as follows.

  That is, a sufficient amount of magnesium contained in the porous carrier according to the present invention first captures and adsorbs the sulfur compound to be bound to the active species metal. Most remain adsorbed, but aluminum releases some sulfur compounds from the catalyst. Moreover, since the porous carrier has an appropriate BET specific surface area, average pore diameter, and pore volume, the inventor presumes that highly active catalytic activity can be maintained for a long time.

  Therefore, by using the steam reforming catalyst according to the present invention, it is possible to easily obtain a reaction mixed gas mainly composed of C1 component and hydrogen by decomposing hydrocarbon without reducing the sulfur content.

The porous carrier and the steam reforming catalyst according to the present invention can suppress the sintering of the porous carrier and the active species metal, and can maintain high sulfur catalytic resistance as well as high-performance catalytic activity over a long period of time. it can.
Therefore, in this invention, even if it is a hydrocarbon raw material containing a trace amount sulfur, steam reforming can be performed efficiently and the mixed gas of C1 component and hydrogen can be manufactured.

  The present invention can provide a carrier excellent in sulfur poisoning resistance that can be industrially produced in large quantities. Furthermore, when a catalyst using the carrier is used, the C1 component in the steam reforming reaction of hydrocarbon containing sulfur and This is very useful when producing a mixed gas of hydrogen.

  A typical embodiment of the present invention is as follows.

  The BET specific surface area value is the B.B. E. T.A. Measured by the method.

  The size of the supported active metal was measured using a transmission electron microscope (JEOL Ltd., JEM-1200EXII).

  The contents of Mg and active species metal were obtained by dissolving a sample with an acid and analyzing it using a plasma emission spectroscopic analyzer (Seiko Electronics Co., Ltd., SPS4000).

  For the pore diameter and pore volume, an adsorption isotherm of nitrogen at 75K was prepared using a high-speed specific surface area / pore distribution measuring device (ASAP2010, manufactured by Micromeritics), and the adsorption isotherm was reduced by the BJH method. The pore distribution curve was obtained and obtained.

  For the steam reforming reaction, a laboratory-level single pipe fixed bed flow type was used. Although what is generally marketed may be sufficient, examination of this invention was implemented with the self-made apparatus. A gas chromatograph was used for component analysis after the modification.

Example 1 <Preparation of carrier>
73.3 g of Mg (NO ₃ ) ₂ .6H ₂ O and 42.9 g of Al (NO ₃ ) ₃ .9H ₂ O were dissolved in water to make 600 ml. Separately, a mixed solution of 400 ml of alkali was prepared by combining 60 ml of NaOH (concentration of 14 mol / L) and 14.5 g of Na ₂ CO ₃ . A mixed solution of the magnesium salt and aluminum salt was added to the alkali mixed solution, and aging was performed at 90 ° C. for 5.5 hours to obtain a hydrated double hydroxide. This was separated by filtration, dried, pulverized, and heat-treated at 480 ° C. for 20 hours. The obtained catalyst carrier had a BET of 80.0 m ² / g, an average pore diameter of 237 mm, and a pore volume of 0.58 cm ³ / g.

<Catalyst preparation and catalytic activity evaluation>
To the carrier component, acicular boehmite equivalent to 8.5% by weight of the carrier was added to form a spherical shape having a diameter of 3 mm. At this time, the Mg content was 32.5 wt% as a result of analysis. Nickel nitrate was impregnated so as to contain 27 wt% of Ni metal as a catalyst body, dried, and then heat treated at 700 ° C. for 1 h. Furthermore, reduction treatment was performed at 780 ° C. for 2 hours in 5 vol% hydrogen-nitrogen gas, and Ni metal was deposited and fixed on the support to prepare a catalyst. As a result of the analysis, the Ni metal loading was 26.9 wt%. The size of the Ni metal was 8 nm.
Further, the amounts of magnesium and aluminum contained were 23.6 wt% and 13.6 wt% in terms of metal, respectively, and the molar ratio of magnesium element to aluminum element (Mg: Al) was 1.9: 1.
In a flow reactor, 6 cc (6.63 g) of the obtained catalyst was passed through a city gas 13A having a total sulfur content of 5 ppm at GHSV = 500 h ^−1, at a temperature of 430 ° C. and S / C = 2, and steam reforming of the catalyst. Quality activity evaluation was performed. Only the C1 component and hydrogen were confirmed even at a reaction time of 25 h, and no gas component of C2 or higher was detected.

Example 2
In the same manner as in Example 1, 63.1 g of Mg (NO ₃ ) ₂ .6H ₂ O, 57.7 g of Al (NO ₃ ) ₃ .9H ₂ O, 60 ml of NaOH (14 mol / L concentration) and Na ₂ CO ₃ 19. The reaction was performed at 50 ° C. for 3 h using 6 g. Heat treatment was performed at 950 ° C. for 1 h. The obtained catalyst support had a BET of 268 m ² / g, an average pore diameter of 292 mm, and a pore volume of 3.69 cm ³ / g.

The carrier component was added with titania corresponding to 18.9 wt% relative to the carrier, formed into a disk shape having a diameter of 10 mm, crushed and sieved to obtain crushed pellets of 1 to 1.5 mm. At this time, the Mg content was 22.2 wt% as a result of analysis. The obtained pellets were heat treated at 500 ° C. for 2 hours, then dipped in a rhodium nitrate solution and dried to obtain a catalyst precursor containing 1.5 wt% of Rh metal as a catalyst body. After drying, heat treatment was performed at 450 ° C. for 1 h. Further, hydrogen reduction treatment was performed for 1 h at 500 ° C. in 5 vol% hydrogen-nitrogen gas. As a result of the analysis, the amount of Rh metal supported was 1.50 wt%. The size of the Rh metal was 3 nm.
Moreover, the amounts of magnesium and aluminum contained were 21.1 wt% and 14.6 wt%, respectively, in terms of metal, and the molar ratio of magnesium element to aluminum element (Mg: Al) was 1.6: 1.
3 cc (7.02 g) of the obtained catalyst was used as a raw material by vaporizing isooctane having a total sulfur content of 30 ppm in a flow reactor. The steam reforming activity of the catalyst was evaluated at GHSV = 20000h ⁻¹ , temperature 550 ° C., and S / C = 2.4. Even at a reaction time of 7 h, only the C1 component and hydrogen were confirmed, and no gas component of C2 or higher was detected.

Example 3
In the same manner as in Example _{1, Mg (NO 3) 2} · 6H 2 O 83.2g and _{Al (NO 3) 3 · 9H} 2 O 28.3g, NaOH 58ml (14mol / L concentration) and _Na 2 _CO 3 9. The reaction was performed at 85 ° C. for 12 h using 6 g. Next, heat treatment was performed at 1150 ° C. for 1 h. The obtained catalyst carrier had a BET of 32 m ² / g, an average pore diameter of 256 mm, and a pore volume of 0.28 cm ³ / g.

A zirconia sol was added to the carrier component so that zirconia corresponding to 3.2% by weight of the carrier was added, and compression-molded into a cylindrical shape having a diameter of 2 mm and a height of 3 mm. At this time, the Mg content was 42.8 wt% as a result of analysis. This was dipped in a ruthenium nitrate solution and dried to obtain a catalyst containing 3 wt% of Ru metal as a catalyst body. After drying, heat treatment was performed at 450 ° C. for 1 h. Further, hydrogen reduction treatment was performed for 1 h at 500 ° C. in 5 vol% hydrogen-nitrogen gas. As a result of the analysis, the Ru metal loading was 2.9 wt%. The size of the Ru metal was 6 nm.
Moreover, the amounts of magnesium and aluminum contained were 41.5 wt% and 10.7 wt%, respectively, in terms of metal, and the molar ratio of magnesium element to aluminum element (Mg: Al) was 4.3: 1.
Using the obtained catalyst 10 cc (8.99 g), the activity of the catalyst was evaluated using kerosene having a total sulfur content of 8 ppm at LHSV = 2h ⁻¹ , temperature 800 ° C., and S / C = 3 in a flow reactor. . Even in the reaction time of 3 hours, the mixed gas was mainly composed of C1 component and hydrogen. The conversion rate of kerosene at the reaction time of 3 h was 98.8%.
The average molecular formula of kerosene is C ₆ H ₁₄ , and the conversion rate of kerosene is
Kerosene conversion rate (%)
= (1- (total number of hydrocarbon molecules in product gas / total number of hydrocarbon molecules in feed kerosene)) × 100
Sought by.

Example 4
In the same manner as in Example _{1, Mg (NO 3) 2} · 6H 2 O 75.3g and _{Al (NO 3) 3 · 9H} 2 O 28.3g, Ni (NO 3) 2 · 6H 2 O 9.0g, NaOH Using 58 ml (14 mol / L concentration) and Na ₂ CO ₃ 9.6 g, a reaction was performed at 80 ° C. for 6 hours, and a heat treatment was performed at 700 ° C. for ₂ hours. The obtained catalyst support had a BET of 177 m ² / g, an average pore diameter of 278 mm, and a pore volume of 1.34 cm ³ / g.

To the above product, granular θ-alumina equivalent to 2.0 wt% of the carrier was added to form a spherical shape having a diameter of 3 mm, and heat-treated at 900 ° C. for 5 hours. At this time, the Mg content was 39.3 wt% as a result of analysis. Further, reduction treatment was performed at 820 ° C. for 1 h in 5 vol% hydrogen-nitrogen gas to deposit and fix Ni metal on the support to prepare a catalyst. As a result of the analysis, the Ni metal loading was 9.2 wt%. The size of the Ni metal was 9 nm.
The amounts of magnesium and aluminum contained were 35.4 wt% and 12.1 wt%, respectively, in terms of metal, and the molar ratio of magnesium element to aluminum element (Mg: Al) was 3.3: 1.
4 cc (4.88 g) of the obtained catalyst was flowed in a flow reactor, propane having a total sulfur content of 6 ppm was flowed at GHSV = 4000 h ⁻¹ , the steam reforming activity of the catalyst at a temperature of 650 ° C. and S / C = 3 Evaluation was performed. Only the C1 component and hydrogen were confirmed even at a reaction time of 10 h, and no gas component higher than C2 was detected.

Example 5
In the same manner as in Example _{1, Mg (NO 3) 2} · 6H 2 O 70.5g and _{Al (NO 3) 3 · 9H} 2 O 46.9g, NaOH 59ml (14mol / L concentration) and _Na 2 _CO 3 15. Using 9 g, the reaction was carried out at 105 ° C. for 4.5 h, and heat treatment was carried out at 550 ° C. for 1 h. The obtained catalyst carrier had a BET of 74 m ² / g, an average pore diameter of 246 mm, and a pore volume of 0.54 cm ³ / g.

Γ alumina corresponding to 6.8 wt% relative to the carrier was added to the carrier component to form a spherical shape having a diameter of 3 mm and heat-treated at 550 ° C. for 20 hours. At this time, the Mg content was 30.7 wt% as a result of analysis. Nickel nitrate and cobalt acetate were impregnated so as to contain 10 wt% of Ni metal as a catalyst body and 5 wt% of Co metal as a catalyst body, dried and then heat treated at 900 ° C. for 0.5 h. Further, reduction treatment was performed at 800 ° C. for 1 hour in 5 vol% hydrogen-nitrogen gas to deposit and fix Ni metal and Co metal on the support to prepare a catalyst. As a result of the analysis, the supported amounts of Ni metal and Co metal were 9.3 wt% and 4.5 wt%, respectively. The size of Ni metal and Co metal was 14 nm.
Further, the amounts of magnesium and aluminum contained were 26.0 wt% and 16.2 wt%, respectively, in terms of metal, and the molar ratio of magnesium element to aluminum element (Mg: Al) was 1.8: 1.
In a flow reactor, 3 cc (3.60 g) of the obtained catalyst was passed through a city gas 13A having a total sulfur content of 4 ppm at GHSV = 12000 h ^−1, at a temperature of 700 ° C. and S / C = 2.8. The steam reforming activity was evaluated. Only the C1 component and hydrogen were confirmed even at a reaction time of 20 h, and no gas component of C2 or higher was detected.

Example 6
In the same manner as in Example 1, 68.4 g of Mg (NO ₃ ) ₂ .6H ₂ O, 50.0 g of Al (NO ₃ ) ₃ .9H ₂ O, 9.0 g of Ni (NO ₃ ) ₂ .6H ₂ O, NaOH Using 33 ml (14 mol / L concentration) and 21.2 g of Na ₂ CO _{3, a} reaction was performed at 75 ° C. for 8 h, and a heat treatment was performed at 1000 ° C. for 1 h. The obtained catalyst carrier had a BET of 40 m ² / g, an average pore diameter of 263 mm, and a pore volume of 0.30 cm ³ / g.

The product was compression molded into a cylindrical shape with a diameter of 2 mm and a height of 2.5 mm, and heat-treated at 1000 ° C. for 14 hours. At this time, the Mg content was 29.2 wt% as a result of analysis. Further, reduction treatment was performed at 840 ° C. in 5 vol% hydrogen-nitrogen gas for 3 hours to precipitate and fix Ni metal on the support to prepare a catalyst. As a result of analysis, the amount of Ni metal supported was 8.1 wt%. The size of the Ni metal was 6 nm.
Further, the amounts of magnesium and aluminum contained were 29.2 wt% and 16.2 wt%, respectively, in terms of metal, and the molar ratio of magnesium element to aluminum element (Mg: Al) was 2.0: 1.
In a flow reactor, 6 cc (5.46 g) of the obtained catalyst was passed through a city gas 13A having a total sulfur content of 1 ppm at GHSV = 1000 h ^−1, at a temperature of 650 ° C. and S / C = 3, steam reforming of the catalyst. Quality activity evaluation was performed. Only the C1 component and hydrogen were confirmed even at a reaction time of 100 h, and no gas component greater than C2 was detected. Also, the conversion rate at 300 h was about 4% lower than the conversion rate at the start.
The conversion rate of city gas 13A is
Conversion rate of city gas 13A (%)
= (1- (total number of hydrocarbon molecules in product gas / total number of hydrocarbon molecules in supplied city gas 13A)) × 100
Sought by.

Example 7
In the same manner as in Example 1, 76.9 g of Mg (NO ₃ ) ₂ .6H ₂ O, 37.5 g of Al (NO ₃ ) ₃ .9H ₂ O, 60.8 ml of NaOH (14 mol / L concentration), and Na ₂ CO ₃ Using 10.6 g, a reaction was performed at 80 ° C. for 12 hours, and a heat treatment was performed at 1000 ° C. for 1.5 hours. The obtained catalyst support had a BET of 38 m ² / g, an average pore diameter of 269 mm, and a pore volume of 0.32 cm ³ / g.

Granular θ-alumina equivalent to 0.1 wt% of the carrier was added to the product to form a spherical shape with a diameter of 3 mm and heat-treated at 1000 ° C. for 12 hours. At this time, the Mg content was 38.6 wt% as a result of analysis. A silver nitrate solution was spray-coated on this and dried to obtain a catalyst containing 18 wt% of Ag metal as a catalyst body. After drying, heat treatment was performed at 450 ° C. for 2 hours. Further, hydrogen reduction treatment was performed for 1 h at 700 ° C. in 5 vol% hydrogen-nitrogen gas. As a result of the analysis, the amount of Ag metal supported was 18.0 wt%. The size of the Ag metal was 12 nm.
Further, the amounts of magnesium and aluminum contained were 30.8 wt% and 11.4 wt%, respectively, in terms of metal, and the molar ratio of magnesium element to aluminum element (Mg: Al) was 3.0: 1.
In a flow reactor, 6 cc (7.13 g) of the obtained catalyst was passed through a city gas 13A having a total sulfur content of 3.5 ppm at GHSV = 830 h ⁻¹ at a temperature of 650 ° C. and S / C = 2.6. The steam reforming activity of the catalyst was evaluated. Only the C1 component and hydrogen were confirmed even at a reaction time of 45 h, and no gas component of C2 or higher was detected. The 45 h conversion was about 2.5% lower than the starting conversion.
The conversion rate of city gas 13A is
Conversion rate of city gas 13A (%)
= (1- (total number of hydrocarbon molecules in product gas / total number of hydrocarbon molecules in supplied city gas 13A)) × 100
Sought by.

Comparative Example 1
In the same manner as in Example _{1, Mg (NO 3) 2} · 6H 2 O 51.3g and _{Al (NO 3) 3 · 9H} 2 O 75.0g, NaOH 62ml (14mol / L concentration) and _Na 2 _CO 3 25. Using 4 g, a reaction was performed at 65 ° C. for 4 hours, and a heat treatment was performed at 1000 ° C. for 1 hour. The obtained catalyst support had a BET of 149 m ² / g, an average pore size of 316 mm, and a pore volume of 2.45 cm ³ / g.

To the above carrier component, θ alumina corresponding to 10.3 wt% relative to the carrier was added to form a spherical shape having a diameter of 3 mm, and heat-treated at 600 ° C. for 10 hours. At this time, the Mg content was 15.5 wt% as a result of analysis. Nickel nitrate was impregnated so as to contain 18.0 wt% of Ni metal as a catalyst body, dried and then heat treated at 770 ° C. for 1 h. Further, a reduction treatment was performed at 790 ° C. for 2 hours in 5 vol% hydrogen-nitrogen gas to deposit and fix Ni metal on the support to prepare a catalyst. As a result of the analysis, the Ni metal loading was 18.0 wt%. The size of the Ni metal was 12 nm.
The amounts of magnesium and aluminum contained were 12.6 wt% and 18.1 wt%, respectively, in terms of metal, and the molar ratio of magnesium element to aluminum element (Mg: Al) was 0.8: 1.
In a flow reactor, 3 cc (3.30 g) of the obtained catalyst was passed through a city gas 13A having a total sulfur content of 5 ppm at GHSV = 500 h ⁻¹ and steam reforming of the catalyst at a temperature of 430 ° C. and S / C = 2. Quality activity evaluation was performed. In the initial stage of the reaction, only the C1 component and hydrogen were confirmed, and no gas component of C2 or higher was detected, but the reaction was blocked after 11 hours. Since the sulfur poisoning resistance was not sufficient, sulfur was bound to Ni and coking was promoted to cause clogging.

Comparative Example 2
8.1 g of MgO and 20.4 g of γAl ₂ O ₃ were combined and a slurry having a solid content of 10 wt% was pulverized with glass beads for 24 hours using a paint shaker. This was filtered off, dried and ground. Further, heat treatment was performed at 1200 ° C. for 1.5 hours. The obtained catalyst carrier had a BET of 7 m ² / g, an average pore diameter of 435 mm, and a pore volume of 0.05 cm ³ / g.

Titania corresponding to 20.4 wt% of the carrier was added to the carrier component, formed into a disk shape having a diameter of 10 mm, crushed and sieved to obtain crushed pellets of 1 to 1.5 mm. At this time, the Mg content was 14.2 wt% as a result of analysis. After heat treatment at 500 ° C. for 2 hours, it was immersed in a rhodium nitrate solution and dried to obtain a catalyst containing 1.5 wt% of Rh metal as a catalyst body. After drying, heat treatment was performed at 450 ° C. for 1 h. Further, hydrogen reduction treatment was performed for 1 h at 500 ° C. in 5 vol% hydrogen-nitrogen gas. As a result of the analysis, the amount of Rh metal supported was 1.50 wt%. The size of Rh metal was 7 nm.
Further, the amounts of magnesium and aluminum contained were 9.9 wt% and 14.9 wt%, respectively, in terms of metal, and the molar ratio of magnesium element to aluminum element (Mg: Al) was 0.7: 1.
3 cc (4.01 g) of the obtained catalyst was used as a raw material by vaporizing isooctane having a total sulfur content of 10 ppm in a flow reactor. The steam reforming activity of the catalyst was evaluated at GHSV = 20000h ⁻¹ , temperature 550 ° C., and S / C = 2.4. In the initial stage of the reaction, only the C1 component and hydrogen were confirmed, and no gas component of C2 or more was detected, but the reaction was blocked after 2 hours of reaction. Due to insufficient sulfur poisoning resistance, clogging caused clogging.

The present invention can provide a carrier excellent in sulfur poisoning resistance that can be produced industrially in large quantities, and further, when a catalyst using the carrier is used, the C1 component in the steam reforming reaction of hydrocarbon containing sulfur and This is very useful when producing a mixed gas of hydrogen.

Claims (3)

It is a composite oxide composed of at least aluminum and magnesium, has a BET specific surface area of 10 to 300 m ² / g, an average pore diameter of 300 mm or less, and a pore volume of 0.1 cm ³ / g or more. 1 or 2 or more types of active species selected from Ru, Rh, Ir, Pt, Pd, Co, Ni, Fe, and Ag having an average particle diameter of 1 to 15 nm a steam reforming catalyst supported metal, the molar ratio of magnesium element and aluminum element of the steam reforming catalyst (Mg: Al) is 1.2: 1 to 5: characterized by 1 Dearuko and Steam reforming catalyst. It is a composite oxide composed of at least aluminum and magnesium, has a BET specific surface area of 10 to 300 m ² / g, an average pore diameter of 300 mm or less, and a pore volume of 0.1 cm ³ / g or more. A porous carrier of a steam reforming catalyst, and at least one element selected from rare earth elements including silicon, zirconium, cerium, titanium, aluminum, yttrium and scandium, group Ia elements and group IIa elements A mixture of oxide, hydroxide, carbonate or hydrated oxide, wherein the Mg content of the mixture is 20 to 50 wt% in terms of Mg, and the mixture has a Ru having an average particle size of 1 to 15 nm. , Rh, Ir, Pt, Pd, Co, Ni, Fe, Ag, a steam reforming catalyst carrying one or more active species metals selected from Ag , A steam reforming catalyst, wherein the steam reforming catalyst has a molar ratio (Mg: Al) of magnesium element to aluminum element of 1.2: 1 to 5: 1 . A reaction mixed gas comprising a gas or liquid hydrocarbon raw material decomposed using the steam reforming catalyst according to claim 1 or 2 to obtain a reaction mixed gas mainly comprising a C1 component and hydrogen. Manufacturing method.