JP5439706B2 - Method for suppressing generation of metal carbonyl and fuel cell system - Google Patents

Description

  An object of the present invention is to provide a catalyst for safely and efficiently suppressing metal carbonyls in a hydrocarbon cracking reaction in which a hydrocarbon and steam are mixed and reacted without interfering with the reforming reaction.

  The present invention provides a catalyst that is more inexpensive as a catalyst that decomposes hydrocarbons and suppresses metal carbonyls, exhibits excellent catalytic activity for hydrocarbon decomposition and removal, and has excellent durability against sulfur poisoning With the goal.

  Another object of the present invention is to effectively decompose and remove hydrocarbons and produce hydrogen by using the catalyst.

  In recent years, technology for early practical application of new energy has been in the spotlight due to global environmental problems. As one of the means, fuel cells are attracting attention. This fuel cell is characterized in that chemical energy is changed to electric energy by electrochemically reacting hydrogen and oxygen, and has high energy efficiency. For practical use, practical research has been actively conducted.

  Hydrogen used as a fuel cell raw material is produced by reforming hydrocarbon-containing fuels such as city gas 13A, LPG, kerosene, gasoline, and naphtha. Examples of reforming methods include SR (steam reforming), POX (partial oxidation), and SR + POX (autothermal). Among these reforming technologies, the reformed gas with high hydrogen concentration can be obtained, so the most emphasis is placed on the study of application to SR cogeneration.

At present, Ni, Co, Fe and the like are used for the active metal species in the steam reforming catalyst, and Pt, Rh, Ru, Ir, Pd and the like are used for the noble metal type. Among these, the catalyst which supported the metal element of Ni and Ru is mainly used from the height of a catalyst activity. Since the base metal element Ni is relatively easy to cause carbon precipitation, it is necessary to use it under conditions where the water vapor / carbon ratio is higher than the theoretical composition, and the operation is complicated. The unit increases and is not effective. In addition, the system can be operated continuously, and not only an expensive control system is required to meet this requirement, but the overall system becomes very complex, which is not economical in terms of manufacturing cost and maintenance. .
In addition, the noble metal element Ru or the like is unlikely to cause carbon precipitation even under a low water vapor / carbon ratio, but it is easily poisoned by sulfur due to sulfur contained in the raw material, and the catalytic activity deteriorates in a short time. End up. Carbon deposition is extremely likely to occur on the sulfur poisoned catalyst, and sulfur poisoning has the disadvantage of triggering carbon deposition. In addition, since the precious metal is expensive, the price of the fuel cell system using the noble metal becomes very expensive, which may be a factor preventing further spread of the fuel cell system.

  From these facts, it is cheaper as a catalyst for cracking hydrocarbons, has a catalytic activity that decomposes and removes hydrocarbons in terms of function, has coking resistance even under low steam, and has excellent resistance to cracking. A catalyst having sulfur poisoning is desired.

In addition, when a catalyst containing nickel is used, it is generally known that nickel carbonyl is generated at 150 ° C. or lower when a certain amount or more of carbon monoxide is present. The amount produced is largely governed by the concentration of carbon monoxide and the temperature in the gas. For example, the amount of nickel carbonyl obtained from chemical equilibrium near 100 ° C. is approximately 3 × 10 ⁻³ ppm of nickel carbonyl when the concentration of carbon monoxide contained in the gas is 1%, and hydrocarbons Is 10 ppm below 10% close to the amount of carbon monoxide contained in the gas mixture subjected to the steam reforming reaction at 600 to 700 ° C.

  In addition to nickel carbonyl and iron carbonyl, there are cobalt carbonyl, tungsten carbonyl, vanadium carbonyl, molybdenum carbonyl, chromium carbonyl, etc., and these are treated as toxic gases. For example, for nickel carbonyl, the work environment allowable maximum concentration (8 hours) is 0.001 ppm, and the lethal concentration (30 minutes) is 30 ppm.

  Conventionally, as a method for removing metal carbonyl, (A) a method for reducing carbon monoxide gas to the limit, (B) a method for simultaneously removing carbon monoxide and metal carbonyl, and (C) only a metal carbonyl to the limit A method of reducing has been studied (Patent Documents 1 to 6).

  As a method of reducing the carbon monoxide to the limit (A), a method using activated carbon or an inorganic porous adsorbent, or a monoxide using a catalyst in which platinum, palladium, manganese, cerium or the like is supported on an alumina carrier. There are carbon decomposition and removal methods, carbon monoxide adsorption / decomposition removal methods using faujasite-type zeolite and / or manganese dioxide-cupric oxide compounds. This is a technique for suppressing the formation of metal carbonyl by removing carbon monoxide, which is a raw material for producing metal carbonyl.

  On the other hand, as a method of simultaneously removing (B) carbon monoxide and metal carbonyl, there is a decomposition removal method using palladium-supported manganese dioxide-cupric oxide.

  As a method for reducing only the metal carbonyl (C), there is an adsorption removal method using Y-type zeolite. In this method, only metal carbonyl is adsorbed and removed by selecting an optimum Y-type zeolite having a Si / Al ratio and a pore diameter.

  In addition, as a method for analyzing and evaluating the amount of metal carbonyl produced, analysis using an atomic absorption spectrophotometer was previously performed, but analysis accuracy in a lower concentration range is required, and recently, Fourier transform infrared spectrophotometry is required. A method using a meter has been generalized (Japanese Patent Laid-Open Nos. 2003-26415, 2003-66019, and 2005-265116).

  Up to now, the adsorption / decomposition process in which carbon monoxide and / or metal carbonyl is generated has not been performed, but the adsorption / decomposition process is performed after moving the object to be processed from the reaction field to another location. Or a dedicated adsorption / decomposition treatment site was installed in the reaction field, and the object to be treated was circulated thereto for adsorption / decomposition treatment. By these methods, carbon monoxide and / or metal carbonyl was more reliably removed.

  However, it may be unavoidable to remove carbon monoxide and / or metal carbonyl in the reaction field. For example, there are cases where there is no place for installing the adsorption / decomposition processing equipment, and there are disadvantages in cost.

  As an example where there is no place to install the adsorption / decomposition equipment, in recent years, there is a miniaturized household fuel cell system.

  One big concept of this system is to finish it in a very compact size considering installation in a detached house or condominium. In order to reduce the total cost of the system, it is necessary to reduce the number of auxiliary equipment and equipment. For this reason, it is impossible to install the adsorption / decomposition equipment as described above.

  In the fuel cell system, hydrogen, carbon monoxide, and carbon dioxide are generated by the reforming reaction. In the case where a nickel reforming catalyst is used, nickel carbonyl is produced if even the temperature condition is met in this reformed gas composition. However, at present, little measures have been taken to suppress the formation of nickel carbonyl in household fuel cell systems.

JP 2001-146406 A JP-A-62-14944 JP 62-136239 A JP-A-8-281063 JP 2004-82034 A Japanese translation of PCT publication No. 2002-520423

  The technique of Patent Document 1 shows a method for producing hydrogen by steam reforming of a fuel containing hydrocarbons using α-alumina as a carrier and Ru as an active metal species. However, it is considered that the Ru-based catalyst is sulfided by the sulfur content contained in the raw material, and coking is promoted by the sulfuration and the catalytic activity is lost.

  With the techniques described in Patent Documents 2 to 6, metal carbonyl production cannot be suppressed in the reaction field.

  There is a high possibility that many technologies such as a fuel cell system will occur in the future in the technology for suppressing the generation or adsorption / decomposition and removal of metal carbonyl in the reaction field.

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

That is, the present invention is a method for suppressing the generation of metal carbonyl in a gas containing carbon monoxide using a catalyst for suppressing metal carbonyl in a reaction field of 150 ° C. or lower, the catalyst suppressing the metal carbonyl. However, it contains magnesium, aluminum and nickel as constituent elements and contains ruthenium, and 1-50% by weight of clay mineral is present with respect to the catalyst, and the clay mineral has an average particle size of 50 nm or less. Ruthenium, rhodium, iridium, platinum, gold, silver, palladium, nickel, cobalt, copper, iron, zinc, vanadium, a catalyst that supports one or two elements selected from manganese , The average particle diameter is 0.5 nm to 10 nm, and the content of metal ruthenium is 0.05 to 5.0 wt% with respect to the catalyst body. A method of inhibiting the occurrence of metal carbonyl, characterized in that (present invention 1).

Further, in the present invention, the average particle diameter of the metal nickel fine particles of the catalyst for suppressing metal carbonyl used in the method for suppressing the generation of metal carbonyl according to the present invention 1 is 1 to 20 nm, and the content of metal nickel is metal This is a method for suppressing the generation of metal carbonyl, which is 0.1 to 20 wt% with respect to the catalyst for suppressing carbonyl (Invention 2).

Further, the present invention is a fuel cell system using the method for suppressing generation of metal carbonyl according to the first or second aspect of the present invention (Invention 3 ).

  Since the catalyst for suppressing metal carbonyl according to the present invention is supported in a state of very fine particles of metal nickel, the area in contact with hydrocarbons and water vapor of metal nickel which is an active metal species is increased and excellent. Have high catalytic activity. Further, even if the content of nickel as an active metal species is reduced in order to make the generation amount of nickel carbonyl as a metal carbonyl as zero as possible, excellent catalytic activity can be maintained by adding ruthenium.

  The catalyst for suppressing metal carbonyl according to the present invention exhibits excellent resistance to sulfur contained in the raw material gas, and can maintain excellent catalytic activity over a long period of time.

  In addition, the catalyst for suppressing metal carbonyl according to the present invention is a catalyst that has little carbon deposition during the reaction and is excellent in coking resistance.

  A reforming catalyst that removes metal carbonyls "in situ" without interfering with the reforming reaction according to the present invention is a catalyst that can suppress metal carbonyls safely and efficiently. The present invention also provides a method of reforming hydrocarbons using the catalyst and removing metal carbonyls “in situ” and using them in fuel cell systems.

  First, a catalyst for suppressing metal carbonyl without hindering the reforming reaction according to the present invention will be described.

  The catalyst for suppressing metal carbonyl according to the present invention is one in which metal nickel and metal ruthenium fine particles are present in a composite oxide composed of magnesium and aluminum.

  The average particle size of the metal ruthenium fine particles of the catalyst body containing magnesium, aluminum and nickel according to the present invention and containing ruthenium is 10 nm or less, and has an excellent catalytic activity which is optimal for hydrogen production. In a catalyst having metal ruthenium fine particles having an average particle diameter exceeding 10 nm, the catalytic activity is reduced in steam reforming in which hydrogen is produced by mixing hydrocarbon gas and water vapor. Preferably it is 9 nm or less, More preferably, it is 8 nm or less. The lower limit of the average particle diameter is about 0.5 nm.

  The content of metal ruthenium in the catalyst body containing magnesium, aluminum, and nickel as constituent elements and containing ruthenium according to the present invention is 0.05 to 5.0 wt% with respect to the catalyst. When the content of metal ruthenium is less than 0.05 wt%, the conversion rate of hydrocarbons decreases. Moreover, when it exceeds 5.0 wt%, a catalyst will become expensive and it is not practical. Preferably it is 0.05-4.5 wt%.

  The average particle diameter of the metal nickel fine particles of the catalyst body containing magnesium, aluminum and nickel according to the present invention and containing ruthenium is preferably 20 nm or less, and has excellent catalytic activity in hydrogen production. In a catalyst having metal nickel fine particles having an average particle diameter of more than 20 nm, the conversion rate of hydrocarbon is lowered in steam reforming in which hydrogen is produced by mixing hydrocarbon gas and water vapor. Furthermore, the amount of nickel carbonyl generated increases. Further, in the case of a catalyst having metallic nickel fine particles exceeding 20 nm, the coking resistance of the catalyst body is remarkably lowered. Preferably it is 10 nm or less, More preferably, it is 8 nm or less. The lower limit of the average particle diameter is about 0.5 nm.

  The content of metallic nickel in the catalyst body containing magnesium, aluminum and nickel according to the present invention and containing ruthenium is preferably 0.1 to 20 wt% with respect to the catalyst. When the content of metallic nickel is less than 0.10 wt%, the conversion rate of hydrocarbons decreases. When it exceeds 20 wt%, the particle size of the metal nickel fine particles exceeds 20 nm, and the coking resistance is significantly lowered. Furthermore, the effect of suppressing the amount of nickel carbonyl generated is also reduced. Preferably it is 0.2 wt%-18 wt%.

  In the catalyst body containing magnesium, aluminum and nickel as constituent elements and containing ruthenium according to the present invention, the nickel metal and the ruthenium metal are preferably present in the vicinity of the surface of the particles constituting the catalyst body. Further, the catalyst body containing gnesium, aluminum and nickel according to the present invention and containing ruthenium is preferably granulated and used in the form of a molded body. You may make it exist in the surface vicinity of the said molded object.

  The ratio of magnesium and aluminum in the catalyst body containing magnesium, aluminum and nickel according to the present invention and containing ruthenium is not particularly limited. The molar ratio is preferably Mg: Al = 4: 1 to 1.2: 1. When magnesium exceeds the above range, it is difficult to easily obtain a molded article having sufficient strength, and when it is less than the above range, it is difficult to obtain the characteristics as a porous carrier.

The specific surface area value of the catalyst body containing magnesium, aluminum and nickel according to the present invention and containing ruthenium is preferably 5 to 320 m ² / g. If it is less than 5 m ² / g, the conversion rate decreases at a high space velocity. When it exceeds 320 m ² / g, industrial production becomes difficult. More preferably ^{10m 2} / ^g~250m 2 / g.

  Next, a method for producing a catalyst body according to the present invention, which contains ruthenium with gnesium, aluminum and nickel as constituent elements will be described.

  The method for producing the catalyst body is not particularly limited as long as it contains magnesium, aluminum, nickel and ruthenium. For example, nickel and ruthenium are supported on a carrier made of magnesium and aluminum by the usual precipitation method, heat impregnation method, room temperature impregnation method, vacuum impregnation method, equilibrium adsorption method, evaporation to dryness method, competitive adsorption method, ion exchange, spray method or coating. A method in which nickel is solid-solved as a spinel crystal structure compound composed of magnesium and aluminum, and metal nickel is deposited on a spinel carrier composed of magnesium and aluminum by heat treatment. Among the methods described above, a method via a spinel crystal structure compound is preferable.

  The catalyst body containing magnesium, aluminum, and nickel as constituent elements and containing ruthenium according to the present invention is manufactured by heating and firing after producing layered double hydroxide particles by coprecipitation reaction with the element constituting the precursor. It is possible to prepare a porous oxide particle powder, and then heat reduction.

  Also known is a method of firing layered double hydroxide particle powder to obtain a composite oxide, and then hydrating the composite oxide with an aqueous solution containing anions to obtain layered double hydroxide particle powder. It has been. In the present invention, nickel and ruthenium may be supported by the following production method. The layered double hydroxide particle powder supporting nickel and ruthenium may be heat-reduced after being heated and fired if necessary.

  That is, a layered double hydroxide particle powder made only of magnesium and aluminum is formed, and after being fired, a porous oxide formed body is formed, and then impregnated with a solution containing nickel and ruthenium to form a porous oxide powder or formed You may carry | support using the method of reproducing | regenerating the layered double hydroxide particle phase containing nickel and ruthenium near the surface of the body.

  In addition, a layered double hydroxide particle powder in which nickel is present on the particle surface is obtained in accordance with the above production method, molded and fired to form a porous oxide molded body, and impregnated with a solution containing ruthenium, The oxide powder or the powder may be supported by a method of regenerating a layered double hydroxide particle phase containing nickel near the surface of the compact and ruthenium near the surface of the compact.

  Further, a layered double hydroxide particle powder in which ruthenium is present on the particle surface is obtained according to the above production method, molded and fired to form a porous oxide molded body, and impregnated with a solution containing nickel, It may be supported by a method of regenerating a layered double hydroxide particle phase containing ruthenium near the surface of the oxide powder or the molded body and nickel near the surface of the molded body.

  Also, a layered double hydroxide particle powder in which nickel and ruthenium are present on the particle surface is obtained according to the above production method, molded and fired to form a porous oxide molded body, and further impregnated with a solution containing nickel and ruthenium. Thus, nickel or ruthenium can be supported in the vicinity of the surface of the porous oxide powder or molded body, and the layered double hydroxide particle phase containing nickel and ruthenium can be supported in the vicinity of the surface of the molded body. good.

  The powdered catalyst obtained as described above may be molded according to each application to be used. The shape and size are not particularly limited, but may be, for example, a spherical shape, a cylindrical shape, a tubular shape, or a shape applied to a honeycomb body. In general, the size of a catalyst body having a spherical, cylindrical, or tubular shape is preferably about 0.1 to 50 mm. Depending on conditions, the strength and pore distribution density of the molded body may be adjusted by adding various binders such as organic substances and inorganic substances. In the present invention, granulation and molding may be performed before the heat treatment.

In the present invention, the catalyst of the present invention 1 or 2 and alumina beads may be mixed and used. By using alumina beads in combination, metal carbonyl can be further suppressed.
The alumina beads to be used in combination include one or more active metal species selected from ruthenium, rhodium, iridium, platinum, gold, silver, palladium, nickel, cobalt, copper, iron, zinc, vanadium, and manganese. It may be supported, preferably copper. The supported amount of the active metal species is preferably 1 to 15 wt% with respect to the alumina beads.
The mixing ratio of the catalyst of the present invention 1 or 2 and alumina beads is preferably 1 to 50% by weight with respect to the catalyst of the present invention 1 or 2.

  With respect to the catalyst according to the present invention, 1 to 50% by weight of clay mineral may be present, and further metal carbonyl can be suppressed by the presence of the clay mineral. If the amount of clay mineral present is less than 1%, the effect of addition is small. When 50% or more of clay mineral is present, the amount of reforming catalyst in the effective volume decreases, so it is necessary to reduce the gas flow rate in order to maintain the catalytic activity. As a result, the catalyst layer needs to have a larger volume. To do. Preferably it is 2.5 to 45%, More preferably, it is 5 to 40%.

  Examples of the clay mineral contained include zeolite, sepiolite, and montmorillonite. The structure of the zeolite is not particularly limited, but faujasite is preferable, and Y-type zeolite is more preferable among the faujasite systems.

  The clay mineral may be included in the catalyst, may be mixed in the catalyst layer as a separate catalyst or catalyst formed body, or may be divided into the catalyst layer as a separate catalyst formed body.

  The shape and size of the clay mineral are not particularly limited, but may be, for example, a columnar shape, a spherical shape, a cylindrical shape, or the like and a size of about 1 to 5 mm.

  In the case of forming a honeycomb shape separately, a method may be freely selected as necessary.

  A kind selected from ruthenium, rhodium, iridium, platinum, gold, silver, palladium, nickel, cobalt, copper, iron, zinc, vanadium, and manganese having an average particle diameter of 50 nm or less as the clay mineral of the catalyst according to the present invention 3 Alternatively, two or more kinds of active metal species may be supported (Invention 4). By supporting the active metal species, a further “in situ” removal effect of metal carbonyl can be obtained.

  When the average particle size of the active metal species such as ruthenium, rhodium, iridium, platinum, gold, silver, palladium, nickel, cobalt, copper, iron, zinc, vanadium, and manganese exceeds 50 nm, the effect of supporting on the clay mineral is obtained. It becomes difficult. Preferably it is 35 nm, More preferably, it is 20 nm.

  The state of the active metal species supported on the clay mineral may be either a metal or an oxide.

  The amount of the active metal species supported on the clay mineral is not particularly limited because it varies depending on the type of the active metal species to be supported and the type of the clay mineral to be supported. 30 wt% may be sufficient.

  Next, a method for producing a mixed gas containing hydrogen from the hydrocarbon according to the present invention will be described.

  The catalyst which consists of any of this invention 1-4 can obtain the mixed reformed gas containing hydrogen by making it contact with hydrocarbon.

In the method for producing a mixed gas containing hydrogen from the hydrocarbon according to the present invention, the reaction temperature is 250 ° C. to 850 ° C., and the molar ratio (S / C) of water vapor to hydrocarbon is 1.0 to 6.0. The raw material gas containing hydrocarbon and water vapor are brought into contact with the catalyst for suppressing the metal carbonyl according to the present invention under the condition that the space velocity (GHSV) is 100 to 100,000 h ⁻¹ .

  When the reaction temperature is less than 250 ° C., the conversion rate of the lower hydrocarbon is low, and when the reaction is carried out for a long time, coking is likely to occur and the catalytic activity may be deactivated at the end. When the temperature exceeds 850 ° C., the active metal tends to cause sintering and the catalytic properties may be deactivated. Preferably it is 300-700 degreeC, More preferably, it is 400-700 degreeC.

  When the molar ratio S / C of water vapor and hydrocarbon is less than 1.0, the coking resistance is lowered. On the other hand, when S / C exceeds 6.0, a large amount of water vapor is required for hydrogen production, which is expensive and unrealistic. Preferably it is 1.5-6.0, More preferably, it is 1.8-5.0.

The space velocity (GHSV) is preferably from 100 to 100,000 h ⁻¹ , more preferably from 1,000 to 10,000 h ⁻¹ .

  The hydrocarbon used in the present invention is not particularly limited, and various hydrocarbons can be used. Examples include saturated aliphatic hydrocarbons such as methane, ethane, propane, butane, pentane, hexane, and cyclohexane, unsaturated hydrocarbons such as ethylene, propylene, and butene, aromatic hydrocarbons such as benzene, toluene, and xylene, and mixtures thereof. It is done. Suitable raw materials that can be industrially used are city gas 13A, natural gas, LPG, kerosene, gasoline, light oil, naphtha, and the like.

  If the hydrocarbon used in the present invention is liquid at room temperature, such as kerosene, gasoline, or light oil, it can be vaporized using a vaporizer.

  The catalyst according to the present invention may be used for autothermal steam reforming and partial oxidation.

  By placing the catalyst according to the present invention in a state of 150 ° C. or lower, which is generally said to produce nickel carbonyl in a gas containing carbon monoxide, the metal carbonyl can be removed in the reaction field. When the temperature exceeds 150 ° C., carbon monoxide generally increases stability and there is no generation of metal carbonyl gas such as nickel carbonyl. The concentration of carbon monoxide is not particularly limited, but may be, for example, 30 vol% or less. When the concentration of carbon monoxide is high and it is desired to more strongly suppress the formation of metal carbonyl, the relative amount of copper, clay mineral, or clay mineral carrying an active metal may be increased.

  The catalyst comprising any one of the present inventions 1 to 4 can be used in a fuel cell system. The catalyst according to the present invention may be installed outside the reforming reaction part, the pre-reforming reaction part and / or the reforming reaction part, the attached process, and the reforming part of the fuel cell system. Preferably, it is installed in the process before and after the reforming reaction part, the pre-reforming reaction part and / or the reforming reaction part.

<Action>
The reason why the catalyst for suppressing metal carbonyl according to the present invention has excellent catalytic activity and sulfur poisoning resistance is not yet clear, but the present inventor presumes as follows.

  Since the catalyst for suppressing metal carbonyl according to the present invention is supported in a state of very fine particles of metal nickel, the area in contact with hydrocarbons and water vapor of metal nickel which is an active metal species is increased and excellent. Have high catalytic activity. Further, even if the content of nickel as an active metal species is reduced in order to make the generation amount of nickel carbonyl as a metal carbonyl as zero as possible, excellent catalytic activity can be maintained by adding ruthenium.

  The reason why the effect of suppressing metal carbonyl in the reforming reaction field by using the reforming catalyst in which the clay mineral according to the present invention or the clay mineral supporting an active metal is present is not yet clear, The inventor estimates as follows.

  The present inventor presumes that the metal carbonyl generation is supported by very fine particles and the content thereof is reduced, so that the metal carbonyl suppression effect is excellent.

  Furthermore, when the clay mineral is mixed, the inventor believes that the generated metal carbonyl has an adsorption action in the clay mineral and an adsorption action and an oxidative decomposition action in the clay mineral supporting the active metal. Estimated.

  Therefore, if the catalyst according to the present invention is used, the reforming reaction field is sufficient even under conditions where a large amount of metal carbonyl is generated without deteriorating the reforming reaction to obtain a mixed reformed gas containing hydrogen. An effective metal carbonyl-inhibiting effect.

  A typical embodiment of the present invention is as follows.

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

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

  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).

  The activity of the obtained catalyst was evaluated using a lab-level single-tube fixed bed flow system (reaction tube volume 100 cc). Although what is generally marketed may be sufficient, examination of this invention was implemented with the self-made apparatus. The component analysis after the reforming reaction was performed using a gas chromatograph.

JP-A-2003-66019 was referred to for analysis of the amount of metal carbonyl produced by the obtained catalyst. Specifically, the target gas is circulated through a collection tube cooled to −150 to −190 ° C. to collect metal carbonyl, and then the temperature is raised to 20 to 30 ° C., and the metal carbonyl is vacuumed from the collection tube. Then, the method of introducing into an infrared absorption analyzer and analyzing was used. Quantitative analysis of the metal carbonyl was carried out by the calibration curve method from the specific wavelength peak intensity for each obtained metal carbonyl. For example, in the case of nickel carbonyl, quantitative analysis was performed using a peak intensity of 2057 cm ⁻¹ . The specific peak is selected with attention to overlap with other gas component peaks and noise. The lower limit of detection was set to 70 ppb in this study.

A typical embodiment of the present invention is as follows.

Example 1 <Preparation of catalyst>
MgCl ₂ · _{6H 2} O 147.6g and AlCl ₃ · _6H 2 O _35.06g, metal melting obtained by dissolving ruthenium chloride solution 1.151ml containing Ru metal NiCl ₂ · 6H ₂ O 42.57g and 51 g / L 800 ml of a solution, 1200 ml of an alkali mixed solution in which 335.0 ml of NaOH (14 mol / L concentration) and 21.54 g of Na ₂ CO ₃ were dissolved were prepared. A mixed solution of the magnesium salt, aluminum salt, nickel salt, and ruthenium salt was added to the alkali mixed solution, followed by aging at 95 ° C. for 8 hours to obtain a hydrated double hydroxide. This was separated by filtration and dried to obtain a powder. The obtained powder was molded to 3 mmΦ, further heat-treated, and then subjected to reduction treatment to obtain a nickel catalyst (bead shape). The content of nickel in the obtained catalyst was 19.57 wt%, and the size of the metal nickel fine particles was 5 nm. Further, the Ru content in the obtained catalyst was 0.107 wt%, and the size was 1 nm. Separately, using copper nitrate on 3 mmφ alumina beads, copper was supported by 6.82 wt% in terms of metal and heat treated at 350 ° C. for 3 hours.
A catalyst was prepared by mixing 45 wt% of the alumina beads supporting copper with respect to the nickel catalyst. At this time, the nickel catalyst beads were mixed well so that the alumina beads supporting copper were dispersed as uniformly as possible.

<Catalyst activity evaluation>
Using the mixed catalyst, the catalytic activity in the steam reforming reaction was evaluated. 10 cc of a 20 mm diameter stainless steel reaction tube was filled with the catalyst to prepare a catalyst tube.
A raw material gas and water vapor were passed through the catalyst tube (reactor) at a reaction temperature of 300 ° C. to 700 ° C. and a space velocity of 3000 h ⁻¹ to carry out a steam reforming reaction. As the source gas, city gas (13A) and pure methane gas were used.

For the evaluation of the catalyst performance, the C1 conversion rate and the Cn conversion rate (total hydrocarbon conversion rate) shown in the following formula were used.
Example) When pure methane gas is used as the raw material gas C1 conversion (total hydrocarbon conversion)
= (CO + CO ₂ ) / (CO + CO ₂ + CH ₄ )
When using the city gas (13A) in the city gas (13A) Examples) source _{gas, CH 4: 88.5%, C} 2 H 6: 4.6%, C 3 H 8: 5.4%, C ₄ H ₁₀ : About 1.5% was contained, and the Cn conversion rate was calculated by the following formula.
Cn conversion rate (total hydrocarbon conversion rate)
= (CO + CO ₂ ) / (CO + CO ₂ + CH ₄ + C ₂ H ₆ + C ₃ H ₈ )

Tables 1 to 3 show the catalytic performance of the catalysts for decomposing hydrocarbons.
Table 1 shows the reaction temperature (300 ° C. to 300 ° C.) under the reaction conditions in which pure methane gas is used as the raw material gas and GHSV is 3000 h ⁻¹ , 50000 h ⁻¹ , water vapor / carbon (S / C) is 3.0, and the reaction time is 24 h. 700 ° C) and the conversion of carbonized water.
Table 2 shows the reaction time in the case where city gas (13A) is used as the raw material gas, GHSV is 10000 h ⁻¹ , the reaction temperature is 700 ° C., and the water vapor / carbon (S / C) is 1.5 and 3.0. And the relationship between the methane conversion rate and the carbon deposition amount before and after the measurement of the catalyst activity.

<Sulfur poisoning evaluation>
A steam reforming reaction was performed using pure methane gas in which 1 ppm or 5 ppm of TBM (tertiary butyl mercaptan) was added to the raw material gas, and the catalytic activity reduction due to sulfur poisoning was evaluated. The criterion for the decrease in the catalyst activity was confirmed by the time when the Cn conversion rate became 80% or less. Table 3 shows the results of the evaluation of sulfur poisoning resistance at S / C = 3, GHSV = 1000 h ⁻¹ , and a reaction temperature of 700 ° C.

<Metal carbonyl formation and analysis>
Using 10 cc of the obtained catalyst beads, a steam reforming reaction was performed at S / C = 3, GHSV = 1000 h ⁻¹ , and a reaction temperature of 700 ° C. for 3 hours. Thereafter, the temperature was lowered by purging with nitrogen to 100 ° C. Subsequently, a mixed gas having a chemical equilibrium gas composition of the steam reforming reaction at 650 ° C. and S / C = 3 was allowed to flow at GHSV = 1000 h ^{−1 for} 30 minutes. The reaction tube was sealed with a valve and held at 100 ° C. for 1 hour, and then cooled to room temperature and the reaction tube was removed. As a result of quantitative analysis of the amount of nickel carbonyl produced after standing for 3 days, it was less than the lower limit of detection, and it was confirmed that a sufficient removal effect was obtained.

Example 2
Contains 112.8 g of Mg (NO ₃ ) ₂ .6H ₂ O, 27.49 g of Al (NO ₃ ) ₃ .9H ₂ O, 0.341 g of Ni (NO ₃ ) ₂ .6H ₂ O and 51 g / L of Ru metal. A metal-dissolved solution 500 ml in which 24.69 ml of a ruthenium nitrate solution was dissolved, and 1500 ml of an alkali mixed solution in which 183.0 ml (14 mol / L concentration) of NaOH and 10.88 g of Na ₂ CO ₃ were dissolved were prepared. A mixed solution of the magnesium salt, aluminum salt, nickel salt, and ruthenium salt was added to the alkali mixed solution and aged at 80 ° C. for 5 hours to obtain a hydrated double hydroxide. This was separated by filtration and dried to obtain a powder. The obtained powder was molded to 3 mmΦ, further heat-treated, and then subjected to reduction treatment to obtain a nickel catalyst (bead shape). The content of nickel in the obtained catalyst was 0.259 wt%, and the size of the metal nickel fine particles was 1 nm. Further, the Ru content in the obtained catalyst was 4.747 wt%, and the size was 8 nm.
Separately, using copper nitrate on 3 mmφ alumina beads, copper was supported by 6.82 wt% in terms of metal and heat-treated at 300 ° C. for 6 hours. A catalyst was prepared by mixing 5 wt% of the alumina beads supporting copper with respect to the nickel catalyst. At this time, the nickel catalyst beads were mixed well so that the alumina beads supporting copper were dispersed as uniformly as possible.

<Metal carbonyl formation and analysis>
Using 8 cc of catalyst beads obtained by mixing, the steam reforming reaction was performed for 3 hours at S / C = 3, GHSV = 1000 h ⁻¹ , and reaction temperature of 700 ° C. Thereafter, the temperature was lowered by purging with nitrogen to 100 ° C. Subsequently, a mixed gas having a chemical equilibrium gas composition of the steam reforming reaction at 650 ° C. and S / C = 2.5 was allowed to flow at GHSV = 1000 h ^{−1 for} 30 minutes. The reaction tube was sealed with a valve and held at 100 ° C. for 1 hour, and then cooled to room temperature and the reaction tube was removed. As a result of quantitative analysis of the amount of nickel carbonyl produced after standing for 3 days, it was less than the lower limit of detection, and it was confirmed that a sufficient removal effect was obtained.

Example 3
394.4 g of MgSO ₄ · 6H ₂ O, 187.3 g of Al ₂ (SO ₄ ) ₃ · 8H ₂ O, 80.99 g of NiSO ₄ · 6H ₂ O and 3.244 ml of ruthenium chloride solution containing 120 g / L of Ru metal A 1000 ml alkaline mixed solution in which 1500 ml of the dissolved metal solution, 527.0 ml of NaOH (14 mol / L concentration) and 57.16 g of Na ₂ CO ₃ were dissolved was prepared. A mixed solution of the magnesium salt, aluminum salt, nickel salt, and ruthenium salt was added to the alkali mixed solution, followed by aging at 90 ° C. for 10 hours to obtain a hydrated double hydroxide. This was separated by filtration and dried to obtain a powder. The obtained powder was molded to 3 mmΦ, further heat-treated, and then subjected to reduction treatment to obtain a nickel catalyst (bead shape). The content of nickel in the obtained catalyst was 14.71 wt%, and the size of the metal nickel fine particles was 3 nm. Further, the Ru content in the obtained catalyst was 0.317 wt%, and the size was 2 nm.
Separately, using copper nitrate on 3 mmφ alumina beads, copper was supported by 6.82 wt% in terms of metal and heat treated at 400 ° C. for 3 hours. A catalyst was prepared by mixing 30 wt% of the alumina beads supporting copper with respect to the nickel catalyst. At this time, the nickel catalyst beads were mixed well so that the alumina beads supporting copper were dispersed as uniformly as possible.

<Metal carbonyl formation and analysis>
Using 15 cc of the catalyst beads obtained by mixing, the steam reforming reaction was carried out at S / C = 3.0, GHSV = 1000 h ⁻¹ , reaction temperature 700 ° C. for 3 hours. Thereafter, the temperature was lowered by purging with nitrogen to 100 ° C. Next, a mixed gas having a chemical equilibrium gas composition of the steam reforming reaction at 650 ° C. and S / C = 2.7 was allowed to flow for 30 minutes at GHSV = 1000 h ⁻¹ . The reaction tube was sealed with a valve and held at 100 ° C. for 1 hour, and then cooled to room temperature and the reaction tube was removed. After standing for 3 days, a quantitative analysis of the amount of nickel carbonyl was performed. As a result, it was confirmed that the removal effect was 12 ppm.

Example 4
Instead of the copper-carrying alumina beads of Example 3, a molded body comprising a mixture of copper oxide, zinc oxide and alumina, each having a weight ratio of 40, 40 and 20 (copper content is 31.94 wt% in terms of metallic copper). Prepared. A copper-zinc-alumina molded body was prepared in an amount of 30 wt% with respect to the nickel catalyst beads, and mixed well so as to be dispersed as uniformly as possible in the nickel catalyst beads.
Separately, a Y-type zeolite molded body having a diameter of 1 mm and a height of 2 to 3 mm was prepared in an amount of 10 wt% with respect to the above-described nickel catalyst beads.
Here, the Y-type zeolite compact was installed in the upper layer and the lower layer of the catalyst tube (reactor), and the mixture of the nickel catalyst and the copper-zinc-alumina compact was installed in the middle.

<Metal carbonyl formation and analysis>
Using 6 cc of catalyst beads, a steam reforming reaction was performed at S / C = 3.0, GHSV = 1000 h ⁻¹ , and a reaction temperature of 700 ° C. for 3 hours. Thereafter, the temperature was lowered by purging with nitrogen to 100 ° C. Next, a mixed gas having a chemical equilibrium gas composition of the steam reforming reaction at 650 ° C. and S / C = 2.8 was allowed to flow at GHSV = 1000 h ^{−1 for} 30 minutes. The reaction tube was sealed with a valve and held at 100 ° C. for 1 hour, and then cooled to room temperature and the reaction tube was removed. After standing for 3 days, the amount of nickel carbonyl produced was quantitatively analyzed. As a result, it was confirmed that the removal effect was 28 ppm.

Example 5
Instead of the copper-carrying alumina beads of Example 3, Y-type zeolite carrying 1.2 wt% of Pd in terms of metal was prepared as a molded body having a diameter of 1 mm and a height of 2 to 3 mm. The metal size of the supported Pd was confirmed to be 2.5 nm by an electron microscope. 15 wt% of Pd-supported Y-type zeolite was prepared with respect to the above-described nickel catalyst beads by weight. The Pd-supported Y-type zeolite compact was placed in the upper and lower layers of this nickel catalyst.

<Metal carbonyl formation and analysis>
Using 10 cc of catalyst beads, a steam reforming reaction was performed at S / C = 3.0, GHSV = 1000 h ⁻¹ , and a reaction temperature of 700 ° C. for 3 hours. Thereafter, the temperature was lowered by purging with nitrogen to 100 ° C. Subsequently, a mixed gas having a chemical equilibrium gas composition of the steam reforming reaction at 650 ° C. and S / C = 3.3 was allowed to flow at GHSV = 1000 h ^{−1 for} 30 minutes. The reaction tube was sealed with a valve and held at 100 ° C. for 1 hour, and then cooled to room temperature and the reaction tube was removed. After standing for 3 days, a quantitative analysis of the amount of nickel carbonyl was conducted, and it was confirmed that the removal effect was 55 ppm.

Example 6
Instead of the copper-carrying alumina beads of Example 3, Y-type zeolite carrying 5.8 wt% of Ag in terms of metal was prepared as a molded body having a diameter of 1 mm and a height of 2 to 3 mm. The metal size of the supported Ag was confirmed to be 12 nm by an electron microscope. 10 wt% of Ag-supported Y-type zeolite was prepared with respect to the above-described nickel catalyst beads in terms of weight. Ag-supported Y-type zeolite compacts were placed in the upper and lower layers of this nickel catalyst.

<Metal carbonyl formation and analysis>
Using 33 cc of catalyst beads, a steam reforming reaction was performed at S / C = 3.0, GHSV = 1000 h ⁻¹ , and a reaction temperature of 700 ° C. for 3 hours. Thereafter, the temperature was lowered by purging with nitrogen to 100 ° C. Next, a mixed gas having a chemical equilibrium gas composition of the steam reforming reaction at 650 ° C. and S / C = 3.1 was allowed to flow at GHSV = 1000 h ^{−1 for} 30 minutes. The reaction tube was sealed with a valve and held at 100 ° C. for 1 hour, and then cooled to room temperature and the reaction tube was removed. After standing for 3 days, a quantitative analysis of the amount of nickel carbonyl was performed, and as a result, it was confirmed that the removal effect was 62 ppm.

Example 7
1300 ml of a metal-dissolved solution in which 93.41 g of MgCl ₂ .6H ₂ O, 26.41 g of AlCl ₃ .6H ₂ O and 16.29 g of NiCl ₂ .6H ₂ O were dissolved, and 166.0 ml of NaOH (concentration of 14 mol / L) A 700 ml alkali mixed solution in which 16.23 g of Na ₂ CO ₃ was dissolved was prepared. A mixed solution of the magnesium salt, aluminum salt, and nickel salt was added to the alkali mixed solution, followed by aging at 85 ° C. for 12 hours to obtain a hydrated double hydroxide. This was separated by filtration and dried to obtain a powder. The obtained powder was molded to 3 mmΦ, and further heat-treated. The obtained 3 mmφ molded body was spray-supported with 3.244 ml of a ruthenium chloride solution containing 120 g / L of Ru metal and subjected to a reduction treatment to obtain a nickel catalyst (beads).
The content of nickel in the obtained catalyst was 12.10 wt%, and the size of the metal nickel fine particles was 7 nm. Further, the Ru content in the obtained catalyst was 0.521 wt%, and the size was 2 nm.
Separately, using copper nitrate on 3 mmφ alumina beads, copper was supported by 4.39 wt% in terms of metal, and heat-treated at 350 ° C. for 3 hours. A catalyst was prepared by mixing 20 wt% of the alumina beads supporting copper with respect to the nickel catalyst. At this time, the nickel catalyst beads were mixed well so that the alumina beads supporting copper were dispersed as uniformly as possible.

<Metal carbonyl formation and analysis>
Using 15 cc of catalyst beads, a steam reforming reaction was performed at S / C = 3, GHSV = 1000 h ⁻¹ , and a reaction temperature of 700 ° C. for 3 hours. Thereafter, the temperature was lowered by purging with nitrogen to 100 ° C. Next, a mixed gas having a chemical equilibrium gas composition of the steam reforming reaction at 650 ° C. and S / C = 2.4 was allowed to flow for 30 minutes at GHSV = 1000 h ⁻¹ . The reaction tube was sealed with a valve and held at 100 ° C. for 1 hour, and then cooled to room temperature and the reaction tube was removed. After standing for 3 days, the amount of nickel carbonyl produced was quantitatively analyzed. As a result, it was confirmed that the removal effect was 32 ppm.

Example 8
129.8 g of Mg (NO ₃ ) ₂ .6H ₂ O and 31.65 g of Al ₂ (NO ₃ ) ₃ .9H ₂ O are dissolved, 1000 ml of a metal solution, and 251.0 ml of NaOH (concentration of 14 mol / L) are added to Na. A 1000 ml solution in which 16.6 g of ₂ CO ₃ was dissolved was added to prepare a total amount of 2000 ml of an alkali mixed solution. The mixed solution of the magnesium salt and the aluminum salt was added to the alkali mixed solution and aged at 118 ° C. for 11 hours to obtain hydrous double hydroxide core particles.
Subsequently, 42.29 g of Mg (NO ₃ ) ₃ .6H ₂ O, 0.128 g of Ni (NO ₃ ) ₂ .6H ₂ O and 10.31 g of Al (NO ₃ ) ₃ .9H ₂ O were added to this alkaline suspension. And a mixed solution of magnesium salt, nickel salt, aluminum salt and ruthenium salt dissolved in 54.97 ml of ruthenium nitrate solution containing 51 g / L of Ru metal and further aged at 95 ° C. for 6 hours. It was grown topotactically on the oxide particle surface. This was separated by filtration and dried to obtain a powder. The obtained powder was molded to 3 mmΦ, further heat-treated, and then subjected to reduction treatment to obtain a nickel catalyst (bead shape). The content of nickel in the obtained catalyst was 0.066 wt%, and the size of the metal nickel fine particles was 2 nm. Further, the Ru content in the obtained catalyst was 1.212 wt%, and the size was 5 nm. The metal nickel fine particles and metal ruthenium fine particles are presumed to exist only in the vicinity of the particle surface.
Separately, using copper nitrate on 3 mmφ alumina beads, 7.12 wt% of copper was spray-supported in terms of metal and heat-treated at 380 ° C. for 5 hours. A catalyst was prepared by mixing 25 wt% of the alumina beads supporting copper with respect to the nickel catalyst. At this time, the nickel catalyst beads were mixed well so that the alumina beads supporting copper were dispersed as uniformly as possible.

<Metal carbonyl formation and analysis>
Using 22 cc of catalyst beads, a steam reforming reaction was performed at S / C = 3, GHSV = 1000 h ⁻¹ , and a reaction temperature of 700 ° C. for 3 hours. Thereafter, the temperature was lowered by purging with nitrogen to 100 ° C. Subsequently, a mixed gas having a chemical equilibrium gas composition of the steam reforming reaction at 650 ° C. and S / C = 2.6 was allowed to flow at GHSV = 1000 h ^{−1 for} 30 minutes. The reaction tube was sealed with a valve and held at 100 ° C. for 1 hour, and then cooled to room temperature and the reaction tube was removed. After standing for 3 days, the amount of nickel carbonyl produced was quantitatively analyzed. As a result, it was confirmed that the removal effect was 15 ppm.

Example 9
Contains 10.55 g of Mg (NO ₃ ) ₂ .6H ₂ O, 6.952 g of Al (NO ₃ ) ₃ .9H ₂ O, 0.341 g of Ni (NO ₃ ) ₂ .6H ₂ O and 51 g / L of Ru metal. A metal solution obtained by dissolving 4.166 ml of ruthenium nitrate solution was supported on 93 g of 3 mmφ alumina beads by an impregnation adsorption method. The obtained MgAlNiRu-supported alumina beads were heat-treated and then subjected to a reduction treatment to obtain a nickel catalyst (bead shape). The content of nickel in the obtained catalyst was 4.996 wt%, and the size of the metal nickel fine particles was 3 nm. Further, the Ru content in the obtained catalyst was 0.485 wt%, and the size was 1 nm.
Separately, copper nitrate was supported on a 3 mmφ alumina bead using 9.15 wt% copper as a metal, and heat treated at 320 ° C. for 2 h.
A catalyst was prepared by mixing 12 wt% of the alumina beads supporting copper with respect to the nickel catalyst. At this time, the nickel catalyst beads were mixed well so that the alumina beads supporting copper were dispersed as uniformly as possible.

<Metal carbonyl formation and analysis>
Using 10 cc of catalyst beads, a steam reforming reaction was performed at S / C = 3, GHSV = 1000 h ⁻¹ , and a reaction temperature of 700 ° C. for 3 hours. Thereafter, the temperature was lowered by purging with nitrogen to 100 ° C. Subsequently, a mixed gas having a chemical equilibrium gas composition of the steam reforming reaction at 650 ° C. and S / C = 3.5 was allowed to flow at GHSV = 1000 h ^{−1 for} 30 minutes. The reaction tube was sealed with a valve and held at 100 ° C. for 1 hour, and then cooled to room temperature and the reaction tube was removed. After standing for 3 days, the quantitative analysis of the amount of nickel carbonyl was conducted. As a result, it was confirmed that the removal effect was 2 ppm.

Comparative Example 1
The α-alumina powder was fired in air at 1150 ° C. for 10 hours as 3 mmφ spherical beads. A 200 ml solution of 59.47 g of Ni (NO ₃ ) ₂ · 6H ₂ O dissolved in pure water was applied to the α-alumina beads by spraying several times, dried, and then in air at 660 ° C. for 6 hours. Was subjected to firing and reduction treatment. The content of nickel in the obtained catalyst was 11.98 wt%, and the size of the metal nickel fine particles was 58 nm.

<Metal carbonyl formation and analysis>
Using 10 cc of catalyst beads, a steam reforming reaction was performed at S / C = 3, GHSV = 1000 h ⁻¹ , and a reaction temperature of 700 ° C. for 3 hours. Thereafter, the temperature was lowered by purging with nitrogen to 100 ° C. Subsequently, a mixed gas having a chemical equilibrium gas composition of the steam reforming reaction at 650 ° C. and S / C = 3.0 was allowed to flow for 30 minutes at GHSV = 1000 h ⁻¹ . The reaction tube was sealed with a valve and held at 100 ° C. for 1 hour, and then cooled to room temperature and the reaction tube was removed. As a result of quantitative analysis of the amount of nickel carbonyl produced after standing for 3 days, a value exceeding the detection upper limit of 100 ppm was obtained.

Comparative Example 2
1400 ml of a metal dissolving solution in which 82.13 g of MgSO ₄ · 6H ₂ O, 32.41 g of Al ₂ (SO ₄ ) ₃ · 8H ₂ O and 35.05 g of NiSO ₄ · 6H ₂ O were dissolved, and 110.0 ml (14 mol) of NaOH / L concentration) and 600 ml of an alkali mixed solution in which 9.893 g of Na ₂ CO ₃ was dissolved. A mixed solution of the magnesium salt, aluminum salt, and nickel salt was added to the alkali mixed solution, followed by aging at 70 ° C. for 6 hours to obtain a hydrated double hydroxide. This was separated by filtration and dried to obtain a powder. The obtained powder was molded to 3 mmΦ, further heat-treated, and then subjected to reduction treatment to obtain a nickel catalyst (bead shape). The content of nickel in the obtained catalyst was 27.89 wt%, and the size of the metal nickel fine particles was 32 nm.

<Metal carbonyl formation and analysis>
Using 8 cc of catalyst beads, a steam reforming reaction was performed at S / C = 3.0, GHSV = 1000 h ⁻¹ , and a reaction temperature of 700 ° C. for 3 hours. Thereafter, the temperature was lowered by purging with nitrogen to 100 ° C. Next, a mixed gas having a chemical equilibrium gas composition of the steam reforming reaction at 650 ° C. and S / C = 2.8 was allowed to flow at GHSV = 1000 h ^{−1 for} 30 minutes. The reaction tube was sealed with a valve and held at 100 ° C. for 1 hour, and then cooled to room temperature and the reaction tube was removed. As a result of quantitative analysis of the amount of nickel carbonyl produced after standing for 3 days, a value exceeding the detection upper limit of 100 ppm was obtained.

  The catalyst for suppressing generation or adsorption / decomposition and removal of metal carbonyl according to the present invention not only suppresses the generation of metal carbonyl, but also is cheaper, exhibits excellent catalytic activity in terms of function, and is superior to sulfur poisoning. Therefore, there is a high possibility that many needs such as fuel cell systems will occur in the future.

Claims (3)

In a reaction field of 150 ° C. or lower, a method for suppressing the generation of metal carbonyl in a gas containing carbon monoxide using a catalyst for suppressing metal carbonyl, wherein the catalyst for suppressing metal carbonyl comprises magnesium, aluminum, Nickel as a constituent element and containing ruthenium, and 1-50% by weight of clay mineral with respect to the catalyst is present, and the clay mineral has an average particle size of ruthenium, rhodium, iridium, 50 nm or less, A catalyst body supporting one or two elements selected from platinum, gold, silver, palladium, nickel, cobalt, copper, iron, zinc, vanadium, and manganese . The average particle diameter of the metal ruthenium fine particles is 0. 5 to 10 nm, and the content of metal ruthenium is 0.05 to 5.0 wt% with respect to the catalyst body Method of inhibiting the occurrence of metal carbonyls. The catalyst for suppressing metal carbonyl generation according to claim 1, wherein the metal nickel fine particles have an average particle diameter of 1 to 20 nm and the content of metal nickel is a catalyst for suppressing metal carbonyl. The method of suppressing generation | occurrence | production of the metal carbonyl characterized by being 0.1-20 wt% with respect to it. A fuel cell system using the method for suppressing generation of metal carbonyl according to claim 1 or 2 .