JP5394280B2 - Reforming catalyst for hydrogen production, method for producing the same, and method for producing hydrogen using the catalyst - Google Patents

Description

  The present invention relates to a reforming catalyst for hydrogen production, a method for producing the same, and a method for producing hydrogen using the catalyst, and in particular, in the production of hydrogen for fuel cells using petroleum hydrocarbons as fuel oil, low temperature and a small amount of noble metals. Reforming catalyst for hydrogen production capable of effectively proceeding steam reforming reaction with the amount used, and capable of producing hydrogen effectively by shortening the start-up time required to start hydrogen production, and its production method And a hydrogen production method using the catalyst.

  In recent years, with increasing environmental awareness, attention has been focused on energy using hydrogen, which has a low environmental impact. As one of the energy technologies using hydrogen, fuel cells that can extract electric energy from the reaction of hydrogen and oxygen without causing the direct emission of carbon dioxide, which is the cause of global warming, and the destruction of the ozone layer, have attracted attention. ing. As a hydrogen source of the fuel cell, various raw materials such as natural gas, liquid fuel, and petroleum hydrocarbon have been studied. In particular, petroleum hydrocarbons represented by LP gas, naphtha, gasoline, kerosene, etc. It is promising as a hydrogen source because it is distributed over a wide area and in large quantities.

  In order to obtain hydrogen from the above hydrocarbons, it is common to perform a steam reforming reaction in the presence of a steam reforming catalyst. As the steam reforming catalyst, a nickel system in which nickel is supported on a support such as alumina. Catalysts are known. However, nickel-based catalysts have a drawback that they tend to cause a decrease in activity due to carbon deposition. Also, when a hydrocarbon having a large number of carbons is used as a raw material, a large amount of steam is required to coexist, and the steam unit consumption reduces the operating cost. Therefore, it is considered difficult to apply to petroleum-based hydrocarbons both technically and economically. On the other hand, noble metal-based catalysts using noble metals such as ruthenium and rhodium have recently attracted attention as reforming catalysts for hydrocarbons because they have an effect of suppressing carbon deposition and can reduce the amount of water vapor used. However, although these noble metal-based catalysts are excellent in the effect of suppressing carbon deposition, they are susceptible to catalyst poisoning by sulfur, and the effect of suppressing carbon deposition is reduced when subjected to sulfur poisoning.

  Fuel oils composed of petroleum hydrocarbons such as kerosene contain heavy and difficult-to-desulfurize sulfur compounds such as benzothiophene compounds and dibenzothiophene compounds. It is difficult to remove. Even if the amount of these hard-to-desulfurize sulfur compounds contained in the fuel oil is very small, the reforming catalyst is cumulatively affected by these sulfur compounds when hydrogen production is performed for a long time. And when a reforming catalyst receives sulfur poisoning, there exists a problem that carbon deposition to a reforming catalyst is accelerated | stimulated (nonpatent literature 1), Therefore Hydrogen production using the fuel oil comprised from a petroleum-type hydrocarbon However, there is a problem that the performance of the reforming catalyst is easily deteriorated by sulfur poisoning and carbon deposition promoted by sulfur poisoning.

  Generally, in order to produce hydrogen for a fuel cell, a steam reforming reaction and / or a partial oxidation reaction is usually performed at a high temperature of 550 to 800 ° C. in a reformer filled with a reforming catalyst. In a fuel cell system equipped with such a reformer, the lower the temperature required for reforming the fuel oil, the smaller the preheating amount, and the shorter the temperature rise time required for hydrogen production. Can be shortened, which is advantageous. However, when a steam reforming reaction is performed at a low temperature using a conventional reforming catalyst, the reaction in which the fuel oil is converted to hydrogen does not proceed at a sufficient reaction rate, and carbon converted from the fuel oil by a side reaction This deposits on the reforming catalyst and significantly impairs the life of the catalyst, and the carbon converted from the fuel oil causes clogging of the reformer, and contamination by carbon deposited on the unit located downstream of the reforming catalyst. There was a problem that occurred. In order to avoid these problems, for example, at the start of hydrogen production, the temperature of the reforming catalyst and the reformer reach a sufficiently high temperature to obtain the reaction rate necessary for hydrogen conversion from fuel oil. Therefore, the time required to start power generation (startup time) to wait for the temperature rise of the reforming catalyst necessary for the start of hydrogen production in the fuel cell becomes longer, and the power generation in the fuel cell in response to the demand for power There was a problem that supply was delayed. In addition, when the reforming catalyst and the reformer are exposed to a high temperature, the performance of the reforming catalyst is lowered due to thermal deterioration, the catalyst life is shortened, and the reformer is used to prevent its durability from decreasing. There is a problem that the cost increases because an expensive material having high heat resistance is required. In addition, in low-temperature steam reforming at 400 to 525 ° C. using a noble metal-based catalyst such as a ruthenium catalyst, the reaction rate-limiting step is a surface reaction (Non-patent Document 2). When a reforming catalyst is used, this reaction rate-limiting cannot be eliminated, so that a large amount of catalyst is required for producing hydrogen.

  Thus, in order to produce hydrogen at a low temperature using a fuel oil composed of petroleum hydrocarbons such as kerosene, the conversion from fuel oil to hydrogen can be efficiently carried out in a small amount even at low temperature conditions where the reaction rate is slow. There is a need for a reforming catalyst that can be advanced and has the ability to hardly cause carbon deposition even under the influence of sulfur poisoning.

  Examples of the reforming catalyst that suppresses carbon deposition during the reforming of the fuel oil include an active main component composed of at least one platinum group metal as disclosed in JP-A-60-147242 (Patent Document 1), and the like. A steam reforming catalyst comprising a catalyst carrier comprising a promoter comprising silver and a rare earth element and containing silver and a rare earth element in an atomic ratio of 0.1 or more with respect to the active main component. Has been proposed. However, this catalyst is not applied to fuel oil such as kerosene composed of petroleum hydrocarbons, and α-alumina, β-alumina and titania are used for the carrier, so the specific surface area is small and the reaction rate is low. It is not suitable for steam reforming reaction under slow low temperature conditions.

Further, a catalyst in which an active component having a hydroxide as a precursor is supported on a carrier in a highly dispersed manner as disclosed in Japanese Patent Application Laid-Open No. 2007-703 (Patent Document 2) has been proposed. However, this catalyst is intended to be applied to a steam reforming reaction under a high temperature condition of 700 to 800 ° C., and its specific surface area is as low as 5 to 80 m ² / g, and the steam reforming under a temperature condition lower than 550 ° C. It was not applied to the reaction.

  Further, on an inorganic oxide carrier as disclosed in JP 2007-98385 A (Patent Document 3), ruthenium is a catalyst standard, 0.5 to 10% by mass in terms of metal, an alkali metal is a catalyst standard, a metal Containing 0.5 to 10% by mass, ruthenium dispersity is 50% or more, and EPMA shows a line about alkali metal and ruthenium in one direction from the outer surface of the catalyst to the other outer surface so as to pass through the center of the catalyst cross section. A catalyst for producing hydrogen has been proposed in which a large amount of alkali metal is present in a region where ruthenium is present when analytically measured. However, since potassium is used as an alkali metal in this catalyst, and potassium is a highly volatile metal, potassium flows out of the catalyst by the gas stream flowing during use, and is positioned downstream of the reforming catalyst. Unit and other catalysts may be contaminated (Non-patent Document 3).

  Further, in order to economically produce hydrogen, it is common to efficiently use a noble metal or nickel, which is an active metal component, deposited on the support surface with high dispersion by using an impregnation support method or the like. However, in the metal loading method in which the active metal component is introduced from the outside, the bonding force formed between the active metal component and the support surface is weak, and even if the active metal component is introduced in a highly dispersed state on the support When exposed to reforming reaction conditions in which steam coexists, the active metal component sinters (aggregates) on the support surface, making it difficult to maintain the catalyst performance in the initial highly dispersed state. There has been a problem that the catalyst function is likely to deteriorate early and deteriorate.

For example, as disclosed in Japanese Patent Application Laid-Open No. 2000-61307 (Patent Document 4), highly dispersed water vapor having a practical strength that supports ruthenium, which is an active metal component, with a high degree of dispersion of 60% or more and maintains it for a long period of time. A reforming catalyst and a hydrogen production method in which the catalyst is brought into contact with the catalyst to maintain a steam / carbon ratio of 2.8 to 10, a raw material supply amount of 10 h ⁻¹ or less, and a reaction pressure of 2 atm or more have been proposed. However, this catalyst and method are for application to a steam reforming reaction under a high-temperature pressure condition of 750 to 900 ° C, and are not applied to a steam reforming reaction under a temperature condition lower than 550 ° C. In addition, the degree of dispersion of ruthenium in the catalyst after being subjected to the reforming reaction conditions is not clear, but fine ruthenium introduced by loading from the outside of the carrier can maintain its high degree of dispersion. It is assumed that the reaction is limited to a short time in the initial stage of the reaction.

  For this problem, for example, Al in hydrotalcite (a hydrate of porous composite hydroxide) as described in Japanese Patent No. 4211900 (Patent Document 5) is changed into Sc and Rh or Y and Rh. Substituted metal fine particle supported hydrocarbon reforming catalysts have been proposed. However, this catalyst is prepared using a so-called coprecipitation method in which a precipitate is formed by changing the pH of a mixed solution prepared by dissolving a water-soluble salt in water. If the rate of precipitation differs depending on the speed, the components with fast precipitation will precipitate first, and it will not be possible to obtain a precipitate with a uniform composition, and the active metal component cannot be introduced into the catalyst in a highly dispersed state. there were.

  In addition, as disclosed in Japanese Patent No. 4358405 (Patent Document 6), an alumina support has a ruthenium component, a zirconia component, an alkali metal component, an alkaline earth metal component and / or a rare earth metal component, and a cobalt component and / or nickel. Hydrocarbon reforming catalysts that carry components are proposed. However, this catalyst is for suppressing deterioration under high temperature during firing and reaction, and is not applied to a steam reforming reaction under a temperature condition lower than 550 ° C. In addition, since the introduction of various metal components to the alumina carrier is a method by loading, the active metal component is subjected to sintering (aggregation) on the surface of the carrier after being exposed to a reforming reaction condition in which steam coexists for a long time, There was a problem that it was difficult to maintain the catalyst performance in the initial highly dispersed state.

JP 60-147242 A Japanese Patent Laid-Open No. 2007-703 JP 2007-98385 A JP 2000-61307 A Japanese Patent No. 4211900 Japanese Patent No. 4358405

Fuel Association, 68, 39 (1989) J. Jpn. Inst. Energy, 85 (4), 307 (2006). Oil Gas Journal, 74, (7), 73 (1976)

  As described above, in the production of hydrogen for fuel cells using petroleum-based hydrocarbons as fuel oil, the hydrogen production reforming catalyst and the hydrogen production method provided in the prior art provide hydrogen by a reforming reaction at a low temperature. The manufacturing problems could not be solved. This is based on the assumption that the conventional technology has a relatively high reaction rate and a steam reforming reaction at a high temperature, and in the steam reforming reaction at a low temperature and a slow reaction rate, the surface reaction is rate limiting. This is because it was not considered enough. In order to economically produce hydrogen for a long period of time, the precious metal, which is an active metal component, is introduced into the catalyst in a highly dispersed manner, and after the calcination treatment at the time of catalyst production and the reducing atmosphere at the time of hydrogen production use, There is a need for measures to increase the stability of the fine active metal component introduced into the catalyst so that high dispersibility can be maintained, but the reforming catalyst for hydrogen production provided by the conventional method must satisfy all of these. could not.

  Accordingly, an object of the present invention is to solve the above-mentioned problems of the prior art, and for a fuel cell using a petroleum hydrocarbon containing a heavy and difficult-to-desulfurize sulfur compound such as a benzothiophene compound and a dibenzothiophene compound as fuel oil. In hydrogen production, it has high hydrogen production performance even in steam reforming reaction at low temperature, and suppresses adverse effects on reforming catalyst, reformer and unit located downstream thereof due to sulfur poisoning and carbon deposition, To provide a highly functional reforming catalyst for hydrogen production, a method for producing the same, and a method for producing hydrogen using the catalyst, which can effectively produce hydrogen by shortening the startup time required for starting hydrogen production. It is in.

  As a result of intensive investigations focusing on the fact that the steam reforming reaction of hydrocarbons under conditions where the temperature is lower than the conventional reforming reaction temperature and the reaction rate is slow, the surface reaction is rate-limiting, Incorporation of zirconium in the support and uniform introduction into the support can suppress a decrease in catalytic activity in the steam reforming reaction at low temperatures, and the active metal component is highly dispersed and firmly fixed to the support. Therefore, the thermal stability is increased, and the influence of sintering generated during firing and reaction can be reduced, and the specific surface area is increased by reducing the crystallite diameter of the support, and the introduced active metal component It is possible to increase the contact efficiency between the fuel oil for hydrogen production used for the steam reforming reaction and the catalyst, and to use the catalyst having these combined effects. Thus, hydrogen can be efficiently produced even in a steam reforming reaction at a low temperature, and adverse effects on the reforming catalyst, reformer and the unit located downstream thereof due to sulfur poisoning and carbon deposition of the catalyst can be suppressed. In addition, the inventors have found that hydrogen can be efficiently produced by shortening the startup time required for starting hydrogen production, and have completed the present invention.

That is, the reforming catalyst for hydrogen production of the present invention comprises an inorganic composite oxide support containing zirconium, at least one noble metal selected from ruthenium, rhodium, and platinum as an active metal component, and nickel, cobalt as a promoter component. And a specific surface area of 310 m ² / g or more, and the noble metal is dispersed in the inorganic composite oxide support with a dispersity of 60% or more.

  In a preferred example of the reforming catalyst for hydrogen production of the present invention, the inorganic composite oxide support contains alumina, and the crystallite diameter of the alumina is 3 nm or less.

The method for producing a reforming catalyst for hydrogen production of the present invention comprises:
Preparing a homogeneous solution by dissolving zirconium, a composite oxide precursor containing one or more metals other than zirconium, and an active metal precursor containing an active metal component using an organic polydentate ligand;
Adding an aqueous solution of a co-catalyst precursor containing a co-catalyst component to the homogeneous solution for hydrolysis to obtain a hydrolysis product;
And baking the hydrolyzed product at 400 to 800 ° C. in the presence of oxygen.

  In a preferred embodiment of the method for producing a reforming catalyst for hydrogen production of the present invention, the organic polydentate ligand contains at least one selected from polyols, acetoacetates, and polycarboxylic acids. Here, it is more preferable that the organic polydentate ligand contains a diol having 5 or more carbon atoms.

  In the hydrogen production method of the present invention, the fuel oil and steam for hydrogen production are supplied to the reforming section having the above-described reforming catalyst for hydrogen production, and the inlet temperature of the catalyst layer of the reforming section is 520 ° C. or lower. As a characteristic, a steam reforming reaction is performed to obtain a product containing hydrogen.

  In a preferred example of the hydrogen production method of the present invention, the hydrogen production fuel is a kerosene fraction.

  By the reforming catalyst for hydrogen production provided by the present invention and the hydrogen production method using the catalyst, the steam reforming reaction is effectively advanced at a low temperature and the reduction in the catalytic activity is suppressed, and the reforming catalyst, By suppressing adverse effects on the reformer and the units located downstream of it, it becomes possible to start the reforming reaction at a lower temperature than before, and it is possible to operate a fuel cell system with a short time required for startup. Become. In addition, according to the present invention, it is possible to suppress the deterioration of the activity of the reforming reaction and the clogging of the reformer due to coking, thereby enabling long-term hydrogen production. In addition, according to the present invention, due to the reduction in reforming temperature, the performance degradation due to thermal degradation of the reforming catalyst is reduced, and the durability of the reformer is improved without using expensive materials with high temperature durability, It is possible to provide a steam reforming catalyst capable of carrying out economical hydrogen production, such as simplification of the reformer structure, material cost reduction, and application to a low temperature reforming process using an equilibrium shift reaction. .

It is the schematic of the structure of the hydrogen production apparatus used in the Example.

Hereinafter, the contents of the present invention will be described in more detail. The reforming catalyst for hydrogen production of the present invention is selected from zirconium-containing inorganic composite oxide support, at least one noble metal selected from ruthenium, rhodium and platinum as active metal components, and nickel and cobalt as promoter components. And a specific surface area of 310 m ² / g or more, and the noble metal is dispersed in the inorganic composite oxide support with a dispersity of 60% or more.

  The steam reforming catalyst of the present invention can suppress a decrease in catalytic activity in a steam reforming reaction at a low temperature by containing zirconium in a catalyst carrier uniformly and minutely. In addition, the steam reforming catalyst of the present invention has a large specific surface area, and can efficiently contact the fuel oil for hydrogen production used for the steam reforming reaction. Furthermore, in the steam reforming catalyst of the present invention, the noble metal particles are reduced by introducing the noble metal, which is the active metal component, into the inorganic composite oxide support with a high dispersity of 60% or more, and the noble metal is efficiently removed. It can be catalyzed. Moreover, in the steam reforming catalyst of the present invention, by containing a promoter component together with the noble metal, the dispersibility of the noble metal is improved and the catalytic activity is remarkably improved. In addition, the promoter component acts as a wedge for the noble metal, thereby suppressing crystallization of the noble metal, suppressing a decrease in the degree of dispersion of the noble metal that progresses during the reforming reaction, and suppressing deterioration of the catalyst. it is conceivable that. Furthermore, the active metal component is uniformly introduced into the catalyst in a highly dispersed state using an organic polydentate ligand, so that the active metal component is firmly fixed in the support and the stability is increased, so that the firing and reaction can be performed. The influence of sintering that sometimes occurs can be reduced. Through these combined effects, hydrogen production by low-temperature steam reforming reaction using petroleum hydrocarbons as fuel oil by effectively proceeding with surface reaction, which is the rate-limiting step in low-temperature steam reforming reaction Can be carried out effectively.

The reforming catalyst for hydrogen production of the present invention is preferably prepared using a sol-gel preparation method. The inorganic composite oxide prepared by the sol-gel method has a high specific surface area of 310 m ² / g or more even after zirconium is uniformly dispersed even when the zirconium content is high and after baking at 400 to 800 ° C. It becomes possible to have. For example, the reforming catalyst for hydrogen production of the present invention comprises zirconium, a composite oxide precursor containing one or more metals other than zirconium, and an active metal precursor containing an active metal component, an organic multidentate ligand. To prepare a homogeneous solution, hydrolyze an aqueous solution of a co-catalyst precursor containing a co-catalyst component to obtain a hydrolyzed product at 400-800 ° C. in the presence of oxygen, The hydrolysis product can be produced by firing. According to this method, the precipitation of the specific metal component can be suppressed and zirconium can be introduced into the carrier in a highly dispersed state, and the reduction of the specific surface area due to sintering during the formation of the metal oxide can be prevented, A zirconium-containing composite oxide catalyst having a high specific surface area of 310 m ² / g or more is obtained.

Here, a complex oxide precursor containing at least one kind of zirconium and a metal other than zirconium, and an active metal precursor containing an active metal component are uniformly dissolved together with an organic polydentate ligand to form a plurality of metals. A crosslinked complex in which an organic polydentate ligand is coordinated is formed in the solution. By forming this cross-linked complex, the active metal component can be prevented from precipitating prior to other metal components, and the organic polydentate ligand cross-linked to the metal can be heated at a high temperature in the firing treatment. Thus, it is possible to suppress the decrease in specific surface area due to sintering, the decrease due to sublimation of the active metal component and the decrease in dispersibility, and the active metal component can be introduced uniformly and highly dispersed. With these effects, it is possible to prepare a zirconium-containing composite oxide catalyst having both a high specific surface area of 310 m ² / g or more and a high dispersibility with a precious metal dispersion of 60% or more.

  The organic polydentate ligand may be used as a solvent, and the complex oxide precursor and the active metal precursor may be dissolved in the solvent, or the organic polydentate ligand and complex oxide precursor may be dissolved in the solvent. Each of the active metal precursors may be dissolved. Examples of the solvent used in this case include alcohols and esters such as ethanol, propanol, isopropanol, butanol, methyl acetoacetate, ethyl acetoacetate, n-propyl acetoacetate, isopropyl acetoacetate, and t-butyl acetoacetate. When the complex oxide precursor is dissolved together with the organic polydentate ligand, a ligand exchange reaction proceeds between the complex oxide precursor and the organic polydentate ligand. When the ligand exchange reaction proceeds, a crosslinked complex in which an organic polydentate ligand is coordinated to a plurality of metals is generated in the solution. Since this ligand exchange reaction is a reversible reaction, the progress of the ligand exchange reaction can be promoted by removing the component separated from the complex oxide precursor by reactive distillation.

Zirconium contained in the inorganic composite oxide support is effective in suppressing a decrease in catalytic activity, but the specific surface area of the inorganic composite oxide support decreases as the zirconium content increases. Therefore, the zirconium content relative to the inorganic composite oxide support is preferably 0.1 to 50% by mass, more preferably 5 to 50% by mass, and particularly preferably 10 to 50% by mass. When the zirconium content is less than 0.1% by mass, the effect of adding the zirconium component cannot be sufficiently obtained. On the other hand, when the zirconium content exceeds 50% by mass, the specific surface area of the inorganic composite oxide support decreases and the catalyst has a predetermined specific surface area. It is difficult to obtain any of these, and neither is preferable. The reason why the decrease in catalytic activity is suppressed by containing zirconium is not clear, but the affinity between the active metal component and zirconium is high, and the activity introduced by zirconium dispersed uniformly and finely based on the present invention. The metal component is considered to be stabilized. Further, it is considered that zirconium dispersed inside the support activates oxygen atoms in the support, promotes oxidation (gasification) of carbonaceous material attached to the catalyst, and suppresses coke adhesion that causes catalyst deterioration. Therefore, the inorganic composite oxide support preferably contains a metal oxide in addition to zirconium so that the specific surface area of the catalyst is 310 m ² / g or more while containing zirconium. It is preferable to include one or more metal oxides selected from alumina and silicon oxide, and it is particularly preferable to include alumina. In the case where the inorganic composite oxide support includes alumina in order to have a high specific surface area, the alumina preferably has a crystallite diameter of 3 nm or less, and more preferably is amorphous. If the crystallite diameter of alumina is larger than 3 nm, the specific surface area decreases and it becomes difficult to obtain a catalyst having a predetermined specific surface area. Further, when silicon oxide is included, the silicon oxide is preferably amorphous. Here, the term “amorphous” refers to an amorphous state where no diffraction peak is detected in X-ray diffraction (XRD). The crystallite diameter can be measured by a known analysis method such as X-ray diffraction.

  Therefore, the composite oxide precursor used in the present invention is preferably a compound containing at least one selected from aluminum and silicon as a metal other than zirconium and zirconium. As the composite oxide precursor, these metals are used. Inorganic salts and organic salts, such as oxide salts, nitrates, halide salts, carbonates, and organic acid salts, can be used, but the components separated by the above-described ligand exchange reaction can be easily removed by reactive distillation. It is preferable to use a metal alkoxide.

  For example, zirconium oxide precursors include zirconium chloride (IV), zirconium bromide (IV), zirconium iodide (IV), zirconium oxide (IV), zirconium oxychloride, zirconium (IV) ethoxide, zirconium (IV). ) N-propoxide, zirconium (IV) tetraisopropoxide, zirconium n-butoxide, zirconium (IV) tetrabutoxide, zirconium 2-ethylhexanoate (IV), etc., but zirconium (IV) ethoxide or Zirconium (IV) tetraisopropoxide is preferably used.

  Examples of the oxide precursor of alumina include aluminum iodide, basic aluminum carbonate, aluminum acetate, aluminum 2-ethylhexanoate, aluminum acetylacetonate, aluminum hexafluoroacetylacetonate, aluminum ethoxide, and aluminum isopropoxide. Aluminum n-butoxide, aluminum t-butoxide, and the like can be used, but aluminum ethoxide or aluminum isopropoxide is preferably used.

  Examples of silicon oxide oxide precursors include silicon tetrachloride, silicon bromide (IV), silicon iodide (IV), silicon 2-ethylhexanoate, tetraethyl orthosilicate, tetrapropoxysilane, and tetrabutoxysilane. Although it can be used, it is preferable to use tetraethyl orthosilicate or tetrapropoxysilane.

  Examples of the organic polydentate ligand used in the present invention include organic compounds having a plurality of functional groups capable of coordinating to a metal per molecule, such as polyols, polycarboxylic acids, acetoacetates, amino alcohols, and keto alcohols. The coordinating power to metal varies depending on the number and type of functional groups of the organic polydentate ligand, but if an organic polydentate ligand with too strong coordinating power to the metal is used, the subsequent hydrolysis treatment Is not preferable because the progress of hydrolysis is slow. The coordination force between the organic polydentate ligand and the metal is affected by the bulkiness around the atom that coordinates directly to the metal, so the organic polydentate ligand that is bulky around the atom that coordinates directly to the metal Can be used to sterically inhibit the organic polydentate ligand from strongly coordinating to the metal. Therefore, as the organic polydentate ligand, a diol having 5 or more carbon atoms is preferable, and pinacol and 2-methyl-2,4-pentanediol which are diols having 6 carbon atoms are particularly preferable.

  The reforming catalyst for hydrogen production of the present invention contains at least one noble metal selected from ruthenium, rhodium and platinum as an active metal component, and at least one transition metal selected from nickel and cobalt as a promoter component. Containing. In addition, ruthenium and rhodium are preferable as the noble metal, and cobalt is particularly preferable as the transition metal.

  The content of the noble metal depends on the specific surface area of the support, but is generally 0.05 to 10% by mass, preferably 0.1 to 5% by mass, more preferably 0.3 to 3% as a metal with respect to the catalyst mass. % By mass. If the precious metal content is less than 0.05% by mass, the total amount of precious metals functioning as reaction active sites on the catalyst will be reduced and sufficient catalytic activity will not be obtained, and if it exceeds 10% by mass, the cost will increase. This is not preferable. As the noble metal raw material (precursor), a noble metal compound such as noble metal chloride can be used. For example, when ruthenium is contained as a noble metal, ruthenium compounds such as ruthenium trichloride, ruthenium nitrate, ruthenium (III) 2,4-pentandionate can be used as the precursor of the ruthenium active component, and particularly preferably. Ruthenium trichloride (anhydride or hydrate) is used. When rhodium is contained as a noble metal, rhodium compounds such as rhodium chloride, rhodium bromide, rhodium nitrate, rhodium (III) 2,4-pentandionate can be used as a precursor, and platinum is contained as a noble metal. In this case, a platinum compound such as platinum chloride, platinum bromide, or platinum (II) 2,4-pentanedionate can be used as a precursor.

  Here, the degree of dispersion of the noble metal can be measured by a known method for measuring the amount of chemical adsorption to the noble metal. As this method, for example, a pulse injection method using CO gas can be used, and the pulse injection method will be described below. First, when CO gas pulses are continuously injected into the measurement cell containing the catalyst, CO is adsorbed on the surface of the noble metal until the first few pulses, and the amount of CO flowing out of the cell is lower than the amount of injected CO. When CO is adsorbed on the surface of the noble metal and becomes a steady state, most of the injected CO flows out. Then, the CO amount at the time of the first adsorption is subtracted from the CO amount flowing out in the steady state, and the sum of the differences can be obtained as the CO adsorption amount. From the CO adsorption amount thus determined, the number of moles of CO adsorbed on the noble metal is calculated. Further, from the calculated number of moles of CO adsorption and the number of moles of noble metal, the degree of dispersion of the noble metal is obtained by the following formula (1).

  Precious metal dispersion (%) = (number of moles of CO molecules adsorbed per gram of catalyst / number of moles of precious metal contained per gram of catalyst) × 100 (1)

  The degree of precious metal dispersion indicates the ratio of the active sites of precious metals that act on the actual reforming reaction. The larger this value, the more precious metals that are active metal components are distributed in the catalyst. Show.

  Further, the content of the transition metal as a promoter component is preferably 0.1 to 3.0, more preferably 0.1 to 1.0, particularly preferably 0.2 to atomic molar ratio to the noble metal. 0.5. If the atomic molar ratio of the transition metal to the noble metal is less than 0.1, the above-mentioned promoter effect does not sufficiently appear, and if it exceeds 3.0, the excess transition metal adversely impairs the catalytic function of the noble metal. This is not preferable. As the raw material (precursor) of the transition metal, a transition metal compound such as a transition metal nitrate can be used. For example, when cobalt is contained as a transition metal, one or more kinds of cobalt compounds such as cobalt nitrate, cobalt carbonate, cobalt acetate, cobalt hydroxide, and cobalt chloride can be used as the precursor of the cobalt promoter component, Particularly preferably, cobalt nitrate is used. Moreover, when nickel is contained as a transition metal, nickel compounds such as nickel nitrate, nickel carbonate, nickel acetate, nickel hydroxide, and nickel chloride can be used as a precursor.

  By adding an aqueous solution of a co-catalyst precursor containing a co-catalyst component to the solution in which the zirconium-containing cross-linked complex produced by the above method is dissolved, the cross-linked complex is hydrolyzed to obtain a solid precipitate of the hydrolysis product. Can be obtained. At this time, the hydrolysis of the crosslinked complex is preferably performed under mild conditions of 70 to 130 ° C. to suppress rapid progress of the hydrolysis reaction. The hydrolysis reaction is difficult to proceed when the temperature is lower than 70 ° C., and the hydrolysis proceeds rapidly when the temperature exceeds 130 ° C., and precipitation of only specific components is likely to occur, and the uniformity of the resulting zirconium-containing oxide is impaired. Therefore, neither is preferable.

  The solid precipitate of the hydrolysis product generated by the above-mentioned method is collected, and preferably dried at 100 to 150 ° C., and polymerization (gelation) is advanced by dehydration or dealcoholization reaction of the hydrolysis product. . By polymerizing the hydrolysis product, organic polydentate ligands are likely to remain up to a high temperature during firing, and this suppresses sintering of the carrier metal, thereby reducing the composite oxide having a high specific surface area after firing. Can be obtained.

  A zirconium-containing composite oxide is obtained by baking the hydrolyzed product subjected to the above-described treatment in an oxygen-containing atmosphere. Here, oxygen, air, etc. are mentioned as oxygen-containing atmosphere. Note that if the baking treatment is performed at a temperature lower than 400 ° C., it cannot be converted into a stable oxide. If the baking treatment is performed at a temperature higher than 800 ° C., the sintering causes crystallization or increase in the metal oxide particle diameter. Since the specific surface area of the containing complex oxide is lowered, neither is preferable. Therefore, the temperature of a baking process is 400-800 degreeC, Preferably it is 500-700 degreeC. Moreover, in order to remove effectively the water and carbon dioxide which generate | occur | produce by combustion of an organic polydentate ligand, it is preferable to calcinate under ventilation.

The reforming catalyst for hydrogen production of the present invention has a specific surface area of 310 m ² / g or more, preferably 320 m ² / g or more. The larger the specific surface area, the higher the contact efficiency and the reactivity. Further, if the specific surface area is less than 310 m ² / g, the reaction rate-limiting cannot be sufficiently eliminated, which is not preferable. The specific surface area of the catalyst can be obtained by a nitrogen adsorption method.

  The shape of the catalyst of the present invention is not particularly limited, and examples thereof include a spherical shape, a cylindrical shape, a prismatic shape, a tableting shape, a needle shape, a membrane shape, and a honeycomb structure. In addition, the molding of the catalyst is not particularly limited. For example, molding methods such as pressure molding, extrusion molding, rolling granulation molding, and press molding can be used.

  The active metal component introduced into the zirconium-containing composite oxide support by the above method is subjected to a reduction treatment for activation. When a liquid phase reducing agent is used for the reduction treatment, the active metal component is introduced before the catalyst when using the reforming reaction. It is preferable because load such as treatment reduction or heat generation at the initial stage of the reaction can be reduced, and a decrease in the degree of dispersion of the noble metal caused by the reduction treatment of the noble metal can be suppressed. As a method of liquid phase reduction treatment, for example, a 1 to 20% by mass aqueous solution is prepared using a reducing agent such as formic acid, an alkali metal salt of formic acid, formalin, hydrazine, sodium borohydride, and the temperature is from room temperature to 100 ° C. There is a method in which the catalyst is added after heating to temperature.

  The reforming catalyst for hydrogen production of the present invention can further improve the catalytic activity by adding rare earth metals, and can further improve the catalyst life in hydrogen production at a low temperature by suppressing carbon deposition. As the rare earth metal, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, ytterbium and the like can be used, lanthanum and cerium are preferred, and lanthanum is more preferred. These rare earth metals may be used alone or in combination of two or more. As raw materials (precursors) for these rare earth metals, rare earth metal compounds such as chlorides, nitrates and acetates can be used in addition to oxides.

  The rare earth metal can be contained in the catalyst by adding the rare earth metal precursor to the aqueous solution for hydrolysis. The rare earth metal may be introduced into the above-described catalyst by an impregnation method. In this case, the rare earth metal can be selectively distributed on the surface of the catalyst. By selectively distributing the rare earth metal on the surface of the catalyst, a large effect can be obtained with a small amount of addition, and the mechanical strength and heat resistance of the catalyst are improved by coating the surface of the catalyst with the rare earth metal. In order to introduce the rare earth metal into the catalyst by the impregnation method, a solution containing the rare earth metal compound may be immersed in the catalyst. At this time, the solvent is preferably water. Moreover, when making it impregnate, a pore filling method is preferable.

The amount of the rare earth metal is preferably 0.1~5μmol / m ² of the surface area of the catalyst, more preferably 0.5~5μmol / m ^2. If the amount of the rare earth metal exceeds 5 μmol / m ² with respect to the surface area of the catalyst, it is not preferable because the surface exposure of the support is reduced by the coating of the rare earth metal and the catalytic activity is lowered. In addition, if the amount of rare earth metal is less than 0.1 μmol / m ² , the effect of addition is reduced, and neither is preferable. The amount of the rare earth metal contained in the catalyst can be adjusted to the above range by adjusting the concentration of the rare earth metal compound in the aqueous solution for hydrolysis and the concentration of the rare earth metal compound in the solution impregnated in the catalyst.

  The reforming catalyst obtained by the above method is preferably subjected to a reduction treatment before the reforming reaction, but is necessarily required because it is reduced as a result of contact with hydrogen in the reaction gas generated in the reforming reaction. is not.

  A hydrogen production method using the reforming catalyst obtained by the catalyst production method of the present invention performs the steam reforming reaction by supplying the above-described fuel oil for hydrogen production to the reforming section equipped with the reforming catalyst, A product containing hydrogen is obtained. Here, the steam reforming reaction can be started by setting the inlet temperature of the catalyst layer of the reforming section to 520 ° C. or lower, preferably 400 to 520 ° C., more preferably 450 to 500 ° C. Note that starting at a temperature lower than 400 ° C. is not preferable because a steam reforming reaction rate sufficient for hydrogen production cannot be obtained, and a large amount of reforming catalyst is required for hydrogen production. Examples of the reaction format using the reforming catalyst for hydrogen production include a fixed bed type, a moving bed type, and a fluidized bed type, and are not particularly limited. Also, the reactor using the reforming catalyst for hydrogen production is not particularly limited.

  The reforming catalyst for hydrogen production of the present invention can exhibit the effects of the present invention particularly when used in a steam reforming reaction at 520 ° C. or lower, but the steam reforming reaction at a temperature exceeding 520 ° C. and / or Alternatively, it can be used for hydrogen production by a partial oxidation reforming reaction. Therefore, the hydrogen production method using the reforming catalyst for hydrogen production according to the present invention is not limited to always maintaining the inlet temperature of the steam reforming catalyst layer at a temperature condition of 520 ° C. or less, as necessary. The inlet temperature can be raised to 520 ° C. or higher. For example, even when the inlet temperature of the reforming catalyst layer during steady operation eventually exceeds 520 ° C., the present invention is changed from an unsteady state where the inlet temperature is 520 ° C. or lower, such as when the reforming unit is started. By applying this, the startup time can be shortened. Further, the outlet temperature of the reforming catalyst layer in the hydrogen production method is not particularly limited, but is preferably 400 to 800 ° C, more preferably 450 to 750 ° C.

  Moreover, the reforming catalyst for hydrogen production of the present invention can be used alone or in combination with other catalysts. For example, in hydrogen production for a fuel cell, a petroleum-based hydrocarbon that is a fuel oil is converted into a hydrogen-containing gas containing methane at a low temperature in advance using the hydrogen production method of the present invention. The resulting hydrogen-containing gas can be continuously reformed at a high temperature in the downstream reforming section, and the conversion from methane to hydrogen can be further advanced to increase the amount of hydrogen produced.

Liquid hourly space velocity of the fuel oil in the hydrogen production process of the present invention (hereinafter, LHSV) varies depending on the type of fuel oil, are typically 0.01～10Hr ^-1, preferably 0.1～5Hr ^-1 . If the LHSV is extremely low, a reformer having a size larger than necessary with respect to the amount of raw material to be supplied is used, or a minute amount control more than necessary is required for a pump or mass flow for supplying the raw material. It is not preferable. Further, if the LHSV is extremely high, the contact time between the fuel oil and the catalyst layer in the reformer is shortened and the reaction does not proceed, which is not preferable.

  The molar ratio of the amount of water supplied to the amount of carbon in the fuel oil (hereinafter referred to as steam / carbon ratio) depends on the properties of the fuel oil and the type of catalyst, but is usually 0.5 to 10 mol / mol, preferably 1 to 5 mol / mol. If the steam / carbon ratio is extremely low, the steam required for the steam reforming reaction is insufficient, and coke deposition is promoted, so that the catalyst performance deterioration is remarkably accelerated. Also, an extremely high steam / carbon ratio is not preferable because the cost required for the generation and recovery of surplus steam increases. The mixing of fuel oil and water is not particularly limited by the method, but each is heated in a vaporizer and gasified and mixed in a mixer, or either one is heated in a vaporizer. For example, a method may be used in which a gasified product is sent to the other liquid to generate a mixed gas. If the raw material and water are sent to the reformer with inadequate mixing and raw material and water, the steam reforming reaction will not proceed uniformly in the catalyst layer, and the temperature distribution in the catalyst layer and the amount of hydrogen generated will become unstable. It is not preferable.

  The reaction pressure is usually 0 to 10 MPa, preferably 0 to 5 MPa, although it depends on the type of fuel oil. When the reaction pressure exceeds 5 MPa, an equipment using expensive pressure-resistant materials and equipment is required, which is not economically preferable.

  The fuel oil used in the present invention is usually obtained by using a raw material oil containing a petroleum hydrocarbon oil and desulfurizing it. Preferably, the sulfur content is 0.05 mass ppm in terms of sulfur. And a dibenzothiophene compound content of 0.02 mass ppm or less in terms of sulfur, more preferably a sulfur content of 0.05 mass ppm or less and a dibenzothiophene compound content of 0.01 mass ppm or less, particularly Preferably, the compound does not substantially contain a dibenzothiophene compound. If the sulfur content exceeds 0.05 mass ppm and / or the dibenzothiophene compound exceeds 0.02 mass ppm, poisoning of the catalyst with sulfur proceeds and carbon deposition is promoted. These sulfur contents were measured by ultraviolet fluorescence analysis, and the contents of dibenzothiophene compounds were measured by GC-ICP-MS.

Petroleum hydrocarbon oils used as raw material oils include gasoline, naphtha, kerosene, and light oil. Among these, kerosene is preferable for handling, and kerosene specified by JIS or its equivalent is more preferable. In addition, as a method for the desulfurization treatment of the raw material oil, publicly known techniques such as hydrodesulfurization and adsorption separation, which are generally used industrially, can be used singly or in plural. For example, as an example of hydrodesulfurization, using a hydrorefining catalyst containing a transition metal such as cobalt, nickel, molybdenum, tungsten, etc., a reaction temperature of 200 to 400 ° C., a hydrogen / oil volume ratio of 50 to 1000 Nm ³ / m ³ And desulfurization treatment under reaction conditions such as a liquid space velocity of 0.1 to 10 hr ⁻¹ and a pressure of ¹ to 15 MPa-G.

  The fuel oil obtained by the desulfurization treatment of the feedstock oil preferably has a distillation initial boiling point of 140 ° C. or higher and a distillation end point of 300 ° C. or lower, more preferably a distillation initial boiling point of 140 to 180 ° C. and 95% by volume distillation. The point is 270 ° C. or lower, and the distillation end point is 290 ° C. or lower, more preferably the distillation initial boiling point is 140 to 170 ° C., the 95% by volume distillation point is 230 to 270 ° C., and the distillation end point is 240. ˜290 ° C., particularly preferably 95% volume distillation point is 260-270 ° C. and distillation end point is 270-290 ° C. If the distillation initial boiling point is lower than 140 ° C., the flammability becomes high and the handling becomes difficult. Moreover, when the distillation end point is higher than 300 ° C., reforming to hydrogen at a low temperature becomes difficult, which is not preferable. On the other hand, if the 95% volume distillation point exceeds 270 ° C., the content of the dibenzothiophene compound increases, and in particular, the content of the alkyldibenzothiophene compound having a large number of alkyl substituents increases. These distillation properties were measured based on “Petroleum product-distillation test method” defined in JIS K 2254.

  The fuel oil used in the present invention is not particularly limited with respect to the composition of the constituent hydrocarbon, but preferably the content of linear aliphatic saturated hydrocarbon is less than 25% by mass, more preferably linear fatty acid. The content of the group saturated hydrocarbon is less than 25% by mass, and the content of the straight chain aliphatic saturated hydrocarbon having 18 or more carbon atoms is 0.5% by mass or less. If the content of the linear aliphatic saturated hydrocarbon is 25% by mass or more, the linear aliphatic saturated hydrocarbon tends to remain as an unmodified fraction in the production of hydrogen at a low temperature. Further, if the content of the straight-chain aliphatic hydrocarbon having 18 or more carbon atoms exceeds 0.5% by mass, it is preferable because unreformed hydrocarbons are likely to remain in the product in hydrogen production at a low temperature. Absent. The content of the straight chain aliphatic saturated hydrocarbon is measured by gas chromatography.

  The fuel oil used in the present invention preferably has an aromatic content of 20% by volume or less, more preferably 16 to 18% by volume, and a content of aromatic compounds having two or more rings is 1.0. The volume% or less. When the aromatic content exceeds 20% by volume, the deterioration of the reforming catalyst is remarkably advanced, and reforming to hydrogen at a low temperature becomes difficult. Moreover, it is preferable that the fuel oil for hydrogen production of the present invention does not contain an olefin compound. Here, not containing an olefin compound means that it is not quantitatively detected in the analysis. If olefin is contained, carbon is liable to precipitate on the reforming catalyst, and the hydrogen production performance of the catalyst is remarkably deteriorated. The aromatic content, the content of aromatic compounds having two or more rings, and the content of olefin compounds were measured based on hydrocarbon type analysis defined in JPI-5S-49.

  In the present invention, the above-described fuel oil can be used as a raw fuel for hydrogen production alone or mixed with other hydrocarbons.

  The present invention can be implemented in various modes in a hydrogen production apparatus related to a steam reforming reaction, such as a hydrogen plant such as a refinery or a hydrogen production system for a fuel cell in a stationary distributed power source. It is.

  Hereinafter, the effects of the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples.

[Preparation of catalyst]
<Example 1 (Catalyst A)>
Isopropanol produced by dissolving 490 g of aluminum isopropoxide and 186 g of zirconium (IV) tetraisopropoxide (isopropanol adduct) uniformly in 720 g of 2-methyl-2,4-pentanediol under a dehydrating atmosphere. Was distilled for 4 hours while distilling off, and then 3.51 g of ruthenium trichloride was added and isopropanol was removed under reduced pressure. Then, 1.54 g of cobalt (II) nitrate hexahydrate and lanthanum nitrate hexahydrate were added. An aqueous solution in which 13.2 g of the product was dissolved in 500 g of water was added, and hydrolysis was performed at 80 ° C. for 24 hours. The precipitate obtained after hydrolysis is subjected to a gelation reaction at 130 ° C. for 24 hours, and the obtained gel is vacuum-dried at 95 ° C. under vacuum and then dried at 130 ° C. for 16 hours, followed by oxygen at 600 ° C. for 3 hours. After calcination and liquid phase reduction treatment at 40 ° C. using an aqueous hydrazine carbonate solution, the catalyst powder obtained by drying at 150 ° C. for 10 hours is put in a molding machine, and 5 kg at 4 kgf / cm ² . What was press-molded for minutes was pulverized, and what was sieved to a size of 16 to 24 mesh was recovered to obtain catalyst A.

<Example 2 (Catalyst B)>
In the method of Example 1, catalyst B was prepared in the same manner as in Example 1 except that 3.65 g of ruthenium (III) 2,4-pentanedioate was used instead of ruthenium trichloride.

<Comparative Example 1 (Catalyst C)>
Isopropanol produced by dissolving 490 g of aluminum isopropoxide and 186 g of zirconium (IV) tetraisopropoxide (isopropanol adduct) uniformly in 720 g of 2-methyl-2,4-pentanediol under a dehydrating atmosphere. The reaction was distilled for 4 hours while distilling off, then isopropanol was removed under reduced pressure, and then 500 g of water was added and hydrolysis was carried out at 80 ° C. The white precipitate obtained after hydrolysis was subjected to a gelation reaction at 130 ° C., and the obtained white gel was dried under vacuum at 95 ° C. under reduced pressure, and then calcined at 600 ° C. to obtain 175 g of carrier C. After impregnating 180 ml of an aqueous solution in which 13.2 g of lanthanum nitrate hexahydrate was dissolved in 125 g of the obtained carrier C by the pore filling method, drying was performed at 110 ° C. for 16 hours, followed by baking at 600 ° C. in the presence of oxygen for 3 hours. did. The obtained lanthanum-containing support was impregnated with 180 ml of an aqueous solution in which 3.51 g of ruthenium trichloride and 1.54 g of cobalt nitrate (II) hexahydrate were dissolved, and then dried at 150 ° C. for 16 hours. The obtained catalyst is subjected to liquid phase reduction treatment at 40 ° C. using an aqueous hydrazine carbonate solution and dried at 150 ° C. for 10 hours. The obtained catalyst powder is put into a molding machine and pressed at 4 kgf / cm ² for 5 minutes. The molded product was pulverized and the sieved to a size of 16 to 24 mesh was collected to obtain Catalyst C.

<Comparative Example 2 (Catalyst D)>
Into 415 g of ² mm diameter alumina support D (specific surface area 120 m ² / g, pore volume 0.36 ml / g), 34 g of zirconium (IV) chloride was dissolved in water and impregnated by the pore filling method at 110 ° C. 150 ml of an aqueous solution in which 17.5 g of ruthenium trichloride and 10.2 g of cobalt nitrate (II) hexahydrate are dissolved in a zirconium-containing support obtained by drying for 16 hours and subsequently calcining at 650 ° C. for 3 hours in the presence of oxygen. Was impregnated with a pore filling method and then dried at 150 ° C. for 16 hours. The obtained catalyst was heated to 40 ° C. using an aqueous hydrazine carbonate solution, subjected to liquid phase reduction treatment, taken out from the liquid phase and dried at 150 ° C. for 10 hours to obtain Catalyst D.

<Comparative Example 3 (Catalyst E)>
In the method of Example 2, the amount of aluminum isopropoxide used was 600 g, and a catalyst E was prepared in the same manner as in Example 2 except that zirconium (IV) tetraisopropoxide (isopropanol adduct) was not used. Obtained.

  The characteristics of the catalyst obtained as described above are shown in Table 1. In addition, the specific surface area of Table 1 is the value measured by the nitrogen adsorption method. Moreover, the zirconium content and the alumina content, the noble metal content, the cobalt content, and the lanthanum content in the support are values measured by a wet mass spectrometry (ICP-MS) method. The alumina crystallite diameter is a value obtained from the (400) plane diffraction peak (2θ = 66 °) of γ-alumina measured by X-ray diffraction. Further, the precious metal dispersity is represented by the following formula (1) using values measured by a gas adsorption analysis method using carbon monoxide (using a metal dispersity measuring device BEL-METAL-3SP (manufactured by Nippon BEL)). Calculated with

  Precious metal dispersion (%) = (number of moles of CO molecules adsorbed per gram of catalyst / number of moles of precious metal contained per gram of catalyst) × 100 (1)

The number of moles of CO molecules adsorbed to the catalyst in the formula (1) is 20 at 400 ° C. for 30 minutes at 400 ° C. under a hydrogen flow of 50 ml / min. After pre-processing for 5 minutes, based on the CO adsorption amount V ₅₀ when a CO pulse is injected at 50 ° C. in a helium gas stream, the noble metal is supported as a sphere on the surface of the carrier and 1 per noble metal atom. Assuming that one CO molecule is adsorbed, the following formula (2) was used.

Number of moles of CO molecules adsorbed on the catalyst (mol / g) = V ₅₀ /W×(273/(273+t))×(P/101.325)/(22.4×10 ³ ) (2) )
V ₅₀ : CO adsorption amount (ml) at a measurement temperature of 50 (° C.)
W: Sample amount of catalyst (g)
P: Pressure during measurement (kPa)
t: Measurement temperature (° C)

[Evaluation of catalyst]
JIS No. 1 kerosene was hydrodesulfurized at 370 ° C. under conditions of LHSV = 1.0 h ⁻¹ , 370 ° C., hydrogen / oil = 500 Nm ³ / m ³ , pressure 5 MPa using a commercially available cobalt-molybdenum-based desulfurization catalyst. Subsequently, an adsorption treatment was performed using a commercially available zinc oxide adsorbent under the conditions of LHSV = 1.0 h ⁻¹ , 350 ° C., and a pressure of 5 MPa to obtain desulfurized kerosene. Table 2 shows the properties of these JIS No. 1 kerosene and desulfurized kerosene.

  The sulfur content in these oils was measured by ultraviolet fluorescence analysis, and the content of dibenzothiophene compounds was measured by GC-ICP-MS. The distillation properties were measured based on “Petroleum product-distillation test method” defined in JIS K 2254. Further, the content of the linear aliphatic saturated hydrocarbon is measured by gas chromatography. The aromatic content, the content of aromatic compounds having two or more rings, and the content of olefin compounds were measured based on hydrocarbon type analysis defined in JPI-5S-49.

  Next, using the desulfurized kerosene as a raw material, the activity of the catalyst was evaluated with the hydrogen production apparatus shown in FIG. FIG. 1 is a schematic diagram of a configuration of a hydrogen production apparatus used in an example of the present invention. The hydrogen production apparatus of the illustrated example includes a fuel oil tank T110 that stores raw desulfurized kerosene, a water tank T120 that stores water, vaporizers EV110 and EV120 that heat and vaporize each liquid, and each liquid that is heated and vaporized. A mixer M130 for mixing, a reformer R140 for generating a reformed gas containing hydrogen by a steam reforming reaction, and collecting a part of the reformed gas generated by the steam reforming reaction and analyzing its composition Analyzer A150, a gas-liquid separator S160 that cools the reformed gas and separates it into gas-liquid, and a liquid recovery tank T170 that recovers the liquid separated by the gas-liquid separator S160. The reformer R140 houses the reforming catalyst therein. In addition, a temperature and flow rate control device and a heater for heating each part are provided (not shown).

  The flow rate of the liquid in the fuel oil tank T110 and the water tank T120 can be controlled by a pump or mass flow, and is supplied to the respective vaporizers EV110 and EV120. The raw material and water are heated and vaporized by the respective vaporizers EV110 and EV120 and sufficiently mixed in the mixer M130, and then supplied to the reformer R140 containing the reforming catalyst. A part of the reformed gas generated by the steam reforming reaction in the reformer R140 is sent to the analyzer A150, and the gas composition generated by the steam reforming reaction can be analyzed.

  15.0 ml of the catalysts A to E obtained in Examples 1 and 2 and Comparative Examples 1 to 3 are filled in the reformer R140 of the hydrogen production apparatus shown in FIG. R140 was heated at a temperature increase rate of 10 ° C./min, and the temperature was increased until the inlet temperature and the outlet temperature of the reforming catalyst layer were 500 ° C. and 550 ° C., respectively.

Next, using the desulfurized kerosene shown in Table 2 as a raw material, the raw material and water were supplied at 35.6 g / h and 109.8 g / h (raw material LHSV = 3.0 h ⁻¹ , steam / carbon ratio = 2.5 mol, respectively). / Mol), the reaction was carried out under atmospheric pressure conditions for 336 hours in a state where the temperature was controlled so that the inlet temperature and the outlet temperature of the reforming catalyst layer were 500 ° C. and 550 ° C., respectively.

  The reaction product obtained during the above evaluation reaction was sampled in a gas state, and the composition of the reaction product was analyzed by gas chromatography. The catalytic activity of each catalyst in the reforming reaction was evaluated using the C1 conversion obtained by the following formula (3) as an index.

  C1 conversion rate (%) = (number of moles of C1 compound contained in reaction product) ÷ (total number of moles of carbon atoms contained in raw desulfurized kerosene) × 100 Formula (3)

  After performing the evaluation reaction for a predetermined time, the hydrogen production was stopped by stopping the heating of the reformer and simultaneously stopping the supply of water and raw materials. With the reformer temperature lowered to room temperature after the hydrogen production was stopped, the catalyst after the hydrogen production was extracted from each reformer, and the amount of carbon attached to the catalyst was analyzed.

  Table 1 shows the C1 conversion rates and ratios after 24 hours and 288 hours in the evaluation reaction using each catalyst, the amount of carbon adhering to the catalyst after the evaluation reaction, and the state of carbonaceous deposition on the inner wall of the reformer. 3 shows. In addition, these carbon adhesion amounts are the values measured by the wet mass spectrometry (ICP-MS) method.

  Catalyst A showed a high C1 conversion rate even when the content of noble metal, which is an active metal, was smaller than that of Catalyst C and Catalyst D. Catalyst B showed less deterioration with time of the C1 conversion rate than catalyst E containing no zirconium component, and showed a high C1 conversion rate even after the catalyst was used for a long time. From the above results, it can be seen that the reforming catalyst for hydrogen production provided by the present invention is a catalyst that exhibits high performance in hydrogen production at 500 ° C. In addition, by using the reforming catalyst for hydrogen production of the present invention, the amount of carbon adhering to the catalyst after hydrogen production is suppressed, and the performance of the reforming catalyst is reduced by carbon deposition in the steam reforming reaction at 500 ° C. It can be seen that the adverse effect on the reformer is suppressed.

  From these examples, the reforming catalyst for hydrogen production of the present invention enables the start of a reforming reaction at a low temperature, the operation of a fuel cell system with a short start-up time, simplification of the reformer structure and materials It turns out that it becomes possible to implement economical hydrogen production by cost reduction of this.

  The reforming catalyst for hydrogen production provided by the present invention and the hydrogen production method using the catalyst effectively promote a steam reforming reaction at a low temperature and suppress a decrease in catalyst activity, and the reforming catalyst By suppressing the adverse effect on the reformer and the unit located downstream thereof, it is possible to start the reforming reaction at a low temperature, and it is possible to operate the fuel cell system with a short start-up time. Further, it is possible to suppress the deterioration of the activity of the reforming catalyst and the clogging of the reformer due to coking, thereby enabling long-term hydrogen production. Also, by reducing the reforming temperature, the performance degradation due to thermal degradation of the reforming catalyst is reduced, the durability of the reformer is improved without using expensive materials with high temperature durability, and the reformer structure is simplified. It is possible to provide a steam reforming catalyst capable of performing economical hydrogen production, such as reduction of material costs and application to a low temperature reforming process using an equilibrium shift reaction.

T110 Fuel oil tank T120 Water tank EV110 Raw material vaporizer EV120 Water vaporizer M130 Mixer R140 Reformer A150 Analyzer S160 Gas-liquid separator T170 Liquid recovery tank

Claims (7)

The inorganic composite oxide support containing zirconium contains at least one noble metal selected from ruthenium, rhodium and platinum as an active metal component, and at least one transition metal selected from nickel and cobalt as a promoter component, A reforming catalyst for producing hydrogen, wherein the specific surface area is 310 m ² / g or more and the noble metal is dispersed in the inorganic composite oxide support with a dispersity of 60% or more.   The reforming catalyst for hydrogen production according to claim 1, wherein the inorganic composite oxide support contains alumina, and the crystallite diameter of the alumina is 3 nm or less. Preparing a homogeneous solution by dissolving zirconium, a composite oxide precursor containing one or more metals other than zirconium, and an active metal precursor containing an active metal component using an organic polydentate ligand;
Adding an aqueous solution of a co-catalyst precursor containing a co-catalyst component to the homogeneous solution for hydrolysis to obtain a hydrolysis product;
The method for producing a reforming catalyst for hydrogen production according to claim 1, comprising the step of calcining the hydrolysis product at 400 to 800 ° C. in the presence of oxygen.   The method for producing a reforming catalyst for hydrogen production according to claim 3, wherein the organic polydentate ligand contains at least one selected from polyol, acetoacetate, and polycarboxylic acid.   The method for producing a reforming catalyst for hydrogen production according to claim 4, wherein the organic polydentate ligand contains a diol having 5 or more carbon atoms.   A fuel oil and steam for hydrogen production are supplied to a reforming section comprising the reforming catalyst for hydrogen production according to claim 1 or 2, and steam reforming is performed by setting the inlet temperature of the catalyst layer of the reforming section to 520 ° C or lower. A method for producing hydrogen, characterized by carrying out a reaction to obtain a product containing hydrogen.   The method for producing hydrogen according to claim 6, wherein the fuel oil for producing hydrogen is a kerosene fraction.

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