JP2014147868A - Method for producing fuel synthesis catalyst, fuel synthesis catalyst, and method for producing hydrocarbons - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a fuel synthesis catalyst which provides a catalyst having a large specific area while simplifying the production process, and a method for producing hydrocarbons.SOLUTION: The method for producing a fuel synthesis catalyst comprises: a step of forming a carbon-dispersed solution where a water-soluble salt of a metal, which exhibits a catalytic activity for a fuel synthesis reaction, and a co-catalyst are dissolved in an aqueous or an alcohol solution, and a carbon material is dispersed therein; and a step of calcination where the carbon material is removed and an oxide of the metal is formed by calcinating the carbon-dispersed solution obtained in the step of forming a carbon-dispersed solution. Hydrocarbons are synthesized using the catalyst by reacting carbon monoxide and hydrogen under conditions of pressure of 0.5 MPa to 5 MPa and temperature of 423 K and 673 K.

Description

  The present invention relates to a method for producing a fuel synthesis catalyst, a fuel synthesis catalyst, and a hydrocarbon production method.

  A plurality of fuel synthesis methods for synthesizing fuel from synthesis gas containing carbon monoxide and hydrogen as main components are known. One of them is Fisher-Tropsch synthesis (Fisher-Tropsch synthesis, hereinafter referred to as “FT synthesis”). Hereinafter, the FT synthesis reaction will be described as an example of the fuel synthesis method.

  The FT synthesis reaction is a reaction for synthesizing hydrocarbons (liquid fuel) from synthesis gas mainly composed of carbon monoxide and hydrogen, and the synthesized liquid fuel is a clean liquid fuel that does not contain nitrogen and sulfur. It has a high cetane number and can be suitably used as kerosene or light oil.

  Iron, cobalt, nickel, ruthenium, and the like are known as catalysts showing activity in the FT synthesis reaction. Since ruthenium is a rare metal, the manufacturing cost increases. In addition, when nickel is used, methane is mainly synthesized. Therefore, an iron-based catalyst or a cobalt-based catalyst is practically used. As described in Patent Documents 1 and 2, precipitation methods and template methods are known as methods for producing such a catalyst for FT synthesis.

  When the precipitation method is used, for example, an iron nitrate solution and a sodium carbonate solution are dropped into a container to produce an iron-based precipitate, and the iron-based precipitate is washed, filtered, dried and fired to obtain an iron-based catalyst. be able to. Moreover, when adding a promoter, the precipitation method which adds a promoter to an iron nitrate solution is used.

  When using the template method, for example, an organic resin particle having an average particle diameter of several μm is dispersed in an iron nitrate solution to prepare an organic resin dispersed gel. An iron-based catalyst can be obtained.

Japanese Patent No. 4586112 JP 2011-45874 A

  However, when the precipitation method is used, it is difficult to adjust the precipitation conditions such as the concentration, temperature, stirring speed, etc. of the aqueous metal salt solution, and it is difficult to mass-produce a catalyst exhibiting uniform catalytic activity. In order to remove substances that hinder the catalytic activity of the FT synthesis reaction such as the above, it takes time to wash the precipitate with ion-exchanged water, and there is a problem that the wastewater treatment cost increases.

  Furthermore, since the specific surface area of the produced catalyst is small, there is a problem that the efficiency of the FT synthesis reaction is low. In order to increase the specific surface area of the catalyst, there is a method of reducing the average particle diameter of the catalyst. However, when FT synthesis is performed using a slurry bed, the produced liquid hydrocarbon and the catalyst are efficiently separated into solid and liquid. There was also a problem that became difficult.

  In order to obtain a catalyst having a larger specific surface area than when the precipitation method is used, it is preferable to employ the template method as disclosed in Patent Document 1, but the particle size of the organic resin particles used as the template material is large. Therefore, there are many problems such as a problem that a large specific surface area cannot be obtained, a stationary process for preparing an organic resin-dispersed gel, a filtering process for filtering the organic resin-dispersed gel after the stationary process, and a drying process before firing. In addition to the need for a process and a complicated manufacturing process, a part of the catalyst metal ions flows out together with the filtrate due to the filtration process, resulting in a decrease in yield.

  In view of the above-described problems, an object of the present invention is to provide a method for producing a catalyst for fuel synthesis and a method for producing hydrocarbons that can obtain a catalyst having a large specific surface area while simplifying the production process.

  In order to achieve the above-mentioned object, the first characteristic configuration of the method for producing a catalyst for fuel synthesis according to the present invention is the water solubility of a metal exhibiting the catalytic activity of the fuel synthesis reaction as described in claim 1 of the claims. A carbon dispersion solution generation step in which a salt or complex and a cocatalyst are dissolved in water, an alcohol solution or a ketone solution, and a carbon material is dispersed in the solution, and a carbon dispersion solution obtained in the carbon dispersion solution generation step. And a firing step of removing the carbon material and generating the metal oxide by firing.

  In the carbon dispersion solution generation step, a water-soluble salt or complex of a metal exhibiting the catalytic activity of the fuel synthesis reaction and a co-catalyst are dissolved in water, alcohol (including polyol) or ketone solution as a solvent, and a template is added to the solution. A carbon dispersion solution is generated by dispersing the carbon material as the material. In the firing step, the carbon dispersion solution is heated to vaporize moisture, and the metal exhibiting catalytic activity and the carbon material dispersed in the cocatalyst burn and gasify and oxidize the metal exhibiting catalytic activity. A porous body having a product and a promoter is formed. At this time, the cocatalyst functions as a combustion catalyst for the carbon material, and the gasification of the carbon material proceeds efficiently. Since the carbon material as the template material has a smaller particle size than the organic resin particles disclosed in Patent Document 1, a porous body having a very large specific surface area can be obtained.

  In the second characteristic configuration, as described in claim 2, in addition to the first characteristic configuration described above, the water-soluble salt used in the carbon dispersion solution generating step is an iron that exhibits catalytic activity of a fuel synthesis reaction. And a compound of any metal of cobalt, nickel or ruthenium and an inorganic acid or an organic acid.

  As the water-soluble salt of the metal exhibiting the catalytic activity of the fuel synthesis reaction, a compound of any metal of iron, cobalt, nickel or ruthenium and an inorganic acid or an organic acid is preferably used.

  In addition to the first or second characteristic configuration described above, the third characteristic configuration includes a hexagonal network surface of carbon atoms in addition to the first or second characteristic configuration described above. It is the point which is the single or several carbon material selected from either of the carbon materials made into a basic structure.

The carbon material is a general term for materials mainly composed of the element “carbon”. The function and form differ depending on the bonding form of carbon atoms, and sp ³ hybrid orbital bond such as diamond, sp ² hybrid such as graphite. It is classified into orbital coupling and sp hybrid orbital coupling such as carbines. Among these, a carbon material by sp ² hybrid orbital bond having a hexagonal network surface of carbon atoms as a basic structure, for example, selected from graphite, glassy carbon, carbon black, activated carbon, carbon fiber, fullerene or carbon nanotube, coke, etc. A single or a plurality of carbon materials are suitably used as the template material. If the temperature at which the carbon material is combusted is high, the pores collapse during gasification and the specific surface area of the catalyst decreases, but the graphite-based carbon material has a lower combustion temperature than other carbon materials, so it has excellent carbon. It can be suitably used as a material.

  In the fourth feature configuration, in addition to any one of the first to third feature configurations described above, the carbon material used in the carbon dispersion solution generating step has a minimum dimension. The carbon material is in the range of 2 nm to 200 nm.

  If the particle size of the carbon material is too small, the average pore size of the porous catalyst will be small, and the diffusion rate of the synthesis gas in the pore will be slow, and if the particle size of the carbon material is too large, the specific surface area will be small. In either case, there is a risk that improvement in the efficiency of the fuel synthesis reaction may be hindered. However, if a carbon material having a minimum dimension in the range of 2 nm to 200 nm is used, a sufficient specific surface area can be obtained and a decrease in the diffusion rate of synthesis gas in the pores can be avoided. The minimum dimension means the dimension of the minimum part of the shape with respect to various shapes of carbon materials including not only granular carbon materials but also acicular carbon materials.

In the fifth feature configuration, in addition to any of the first to fourth feature configurations described above, the carbon material used in the carbon dispersion solution generating step has a specific surface area. 10m ² / g~2000m ² / g in terms of carbon material in the range of.

If the specific surface area of the carbon material is small, the carbon material has a limited contact area with oxygen in the air in the firing process, and is difficult to burn, and remains in the porous body as charcoal and closes the pores. The specific surface area of the body may be reduced. When the specific surface area of the carbon material is large, the shape retaining property of the metal exhibiting catalytic activity is lost when the carbon material is gasified in the firing step, so that the specific surface area of the porous body may be reduced. However, the specific surface area is used carbon material in the range of 10m 2 ^/ g~2000m 2 ^{/ g,} it is also not the carbon material remains in the firing process, also the carbon material is a metal exhibiting catalytic activity even gasified coercive It is possible to obtain a porous catalyst having a large specific surface area that can ensure shape.

  In the sixth feature configuration, in addition to the fourth or fifth feature configuration described above, the carbon material used in the carbon dispersion solution generation step is carbon black or activated carbon. It is in.

  In particular, when carbon black having a feature of small particle size is used, a catalyst having a good porous body with a large specific surface area can be obtained, and when activated carbon which is a porous body having a large specific surface area is used, A metal exhibiting catalytic activity that has entered the pores can ensure shape retention even when activated carbon is gasified in the firing step, and in any case, a porous catalyst having a large specific surface area can be obtained.

  In the seventh feature configuration, in addition to any of the third to sixth feature configurations described above, the addition amount of the carbon material used in the carbon dispersion solution generation step is as described in claim 7. This is in the range of 0.1% by weight to 70% by weight with respect to the weight of the water-soluble salt.

  If the amount of the carbon material that is the template material is too large, the excess carbon material may be excessively burned locally when it is baked, resulting in a high temperature and a decrease in the specific surface area. If the amount of the carbon material added is too small, a good porous body having a large specific surface area cannot be obtained even if fired. However, when a carbon material is added in the range of 0.1% by weight to 70% by weight with respect to the weight of the water-soluble salt, a porous body having a large specific surface area can be obtained.

  In the eighth feature configuration, as described in claim 8, in addition to any of the third to seventh feature configurations described above, a metal water-soluble salt or complex exhibiting a catalytic activity of the fuel synthesis reaction is provided. The carbon material is added in a range of 0.2 mg to 1 g with respect to 1 ml of the solvent to be dissolved.

  If the carbon material is added in a range of 0.2 mg to 1 g with respect to 1 ml of the solvent, a porous body having a large specific surface area can be obtained.

  In the ninth feature configuration, in addition to any one of the first to eighth feature configurations described above, the firing step is performed at a firing temperature in the range of 423K to 900K. There is in point.

  By firing in the range of 423K to 900K, a porous body can be obtained without breaking the pores generated by gasification of the carbon material during firing.

  In the tenth feature, as described in claim 10, in addition to any of the first to ninth features described above, the promoter includes an alkali metal element, an alkaline earth element, and a rare earth element. A single or a plurality of promoters selected from the group consisting of noble metal elements, copper (Cu), titanium (Ti), zirconium (Zr), molybdenum (Mo), manganese (Mn), and vanadium (V) It is in.

  The co-catalyst functions as a co-catalyst for the FT synthesis reaction, and also functions as a gasification reaction catalyst in the gasification reaction of the carbon material at the time of firing. Oxygen molecules are dissociated and adsorbed on the promoter surface to generate active oxygen atoms, which react with carbon to promote combustion. As such promoters, alkali metal elements, alkaline earth elements, rare earth elements, noble metal elements, copper (Cu), titanium (Ti), zirconium (Zr), molybdenum (Mo), manganese (Mn), vanadium (V Or a single element selected from any of the above.

  According to the eleventh characteristic configuration, as described in claim 11, in addition to the tenth characteristic configuration described above, the amount of the promoter added in the carbon dispersion solution generation step is the amount of the water-soluble salt. This is in the range of 0.1% by weight to 30% by weight with respect to the weight.

  If the cocatalyst is set in the range of 0.1% to 30% by weight with respect to the weight of the water-soluble salt, the gasification reaction of the carbon material is promoted well, and the fuel synthesis reaction also proceeds well. To do.

The characteristic structure of the fuel synthesis catalyst according to the present invention is manufactured by the method for manufacturing a fuel synthesis catalyst having any one of the first to eleventh characteristic structures described above, The surface area is 45 m ² / g or more.

If the catalyst for fuel synthesis has a specific surface area of 45 m ² / g or more, the fuel synthesis reaction proceeds well.

  The characteristic structure of the hydrocarbon production method according to the present invention was produced by the method for producing a fuel synthesis catalyst having any one of the first to eleventh characteristic structures described above. The fuel synthesis catalyst is used to synthesize hydrocarbons by reacting carbon monoxide and hydrogen under pressure conditions of 0.5 MPa to 5 MPa and temperature conditions of 423 K to 673 K.

  If the fuel synthesis catalyst produced by the above-described method for producing a fuel synthesis catalyst is used under such reaction conditions, the fuel synthesis reaction proceeds smoothly, and as a result, hydrocarbons having a large molecular weight can be efficiently obtained. become.

  As described above, according to the present invention, it is possible to provide a method for producing a catalyst for fuel synthesis and a method for producing hydrocarbons that can obtain a catalyst having a large specific surface area while simplifying the production process.

Flow chart of manufacturing method of fuel synthesis catalyst Explanatory diagram of sample production conditions and fuel synthesis catalyst activity characteristic data used in the experiment Illustration of the relationship between the amount of carbon material added and the specific surface area of the catalyst Explanatory diagram of relationship between firing temperature and catalyst specific surface area Explanatory diagram of the relationship between catalyst specific surface area and catalyst activity (CO conversion) (A) is explanatory drawing of the relationship between a carbon material particle diameter and a catalyst specific surface area, (b) is explanatory drawing of the relationship between a carbon material specific surface area and a catalyst specific surface area.

  Hereinafter, an embodiment of a method for producing a catalyst for fuel synthesis and a method for producing a hydrocarbon according to the present invention will be described using an FT synthesis reaction as an example. The catalyst for fuel synthesis is not limited to that used in the FT synthesis reaction, and can be used in a reaction for synthesizing hydrocarbon (liquid fuel) from a synthesis gas such as hydrogen gas and carbon monoxide or carbon dioxide.

  As shown in FIG. 1, the method for producing a catalyst for FT synthesis comprises a water, alcohol or ketone solution as a solvent, a metal water-soluble salt or water-soluble complex exhibiting the catalytic activity of the FT synthesis reaction, and a promoter. Dissolving, adding a carbon material to the solution, stirring and mixing, a carbon dispersion solution generating step for dispersing the carbon material in the solution, and firing the carbon dispersion solution obtained in the carbon dispersion solution generating step in the presence of oxygen Thus, the carbon material is gasified and removed, and a firing step for generating a metal oxide is included.

  The alcohol as the solvent includes not only monohydric alcohols such as methanol and ethanol, but also polyhydric alcohols (polyols) such as ethylene glycol, propylene glycol, trimethylene glycol, 1,4-butanediol, Diols such as 1,5-pentadiol and 1,6-hexanediol. A ketone solution includes acetone and the like. These solvents may be used alone or in combination of two or more.

  The carbon dispersion solution produced in the carbon dispersion solution production process is heated in the firing process to vaporize moisture and alcohol, and further, the metal exhibiting catalytic activity and the carbon material dispersed in the cocatalyst burn and gasify. A porous catalyst having a metal oxide and a cocatalyst exhibiting catalytic activity is formed.

  That is, the carbon material functions as a template material, and the carbon material is gasified and removed in the firing step, whereby a porous catalyst having a very large specific surface area can be obtained. The co-catalyst added to the carbon dispersion solution functions as a co-catalyst for the FT synthesis reaction and also functions as a combustion catalyst for the carbon material, and the firing proceeds efficiently. That is, in the calcination step, oxygen molecules are dissociated and adsorbed on the promoter surface to generate active oxygen atoms, and the oxygen atoms react with the carbon material to promote combustion of the carbon material. The carbon material is more preferably one that contains a small amount of impurities and does not contain sulfur, halogen, or the like that hinders catalytic activity.

  As a metal water-soluble salt exhibiting catalytic activity of FT synthesis reaction, a compound of any of iron (Fe), cobalt (Co), nickel (Ni), and ruthenium (Ru) with an inorganic acid or an organic acid is suitable. Can be used. For example, inorganic compounds such as nitrates, hydroxides, carbonates, sulfates, chlorides, phosphorous oxides, and organic compounds such as vinegar oxides, citric oxides, and oxides can be used. Examples of the iron-based compound include inorganic water-soluble salts such as iron chloride, iron nitrate, and iron sulfate, and organic water-soluble salts such as iron acetate and iron oxalate.

  Examples of suitable metal complexes that show the catalytic activity of the FT synthesis reaction include ammine complexes and hydroxy complexes. Cyano complexes and halogen complexes are not suitable because they contain halogens that inhibit the catalytic activity.

  As a promoter, any of alkali metal elements, alkaline earth elements, rare earth elements, noble metal elements, copper (Cu), titanium (Ti), zirconium (Zr), molybdenum (Mo), manganese (Mn), vanadium (V) Single or multiple promoters selected from these can be used. These cocatalysts can also be suitably used in the form of a water-soluble compound with an inorganic acid or an organic acid.

  The amount of the cocatalyst added is 0 with respect to the weight of the water-soluble salt of the metal exhibiting the catalytic activity of the FT synthesis reaction so that the gasification reaction of the carbon material is favorably promoted and the FT synthesis reaction also favorably proceeds. It is preferably set in the range of 1 wt% to 30 wt%, and more preferably set in the range of 0.1 wt% to 15 wt%.

  In the carbon dispersion solution generation step, the mixing order of the metal showing the catalytic activity of the FT synthesis reaction, the promoter, the carbon material, and the solvent is not particularly limited.

As the carbon material, a single carbon material or a plurality of carbon materials selected from any one of carbon materials having a hexagonal network surface of carbon atoms as a basic structure can be suitably used. The carbon material refers to a material mainly composed of the element “carbon”. The function and form differ depending on the bond form of carbon atoms, and sp ³ hybrid orbital bond such as diamond, sp ² hybrid orbital bond such as graphite. And sp hybrid orbital bonds such as carbins. Among these, a carbon material by sp ² hybrid orbital bond having a hexagonal network surface of carbon atoms as a basic structure, for example, selected from graphite, glassy carbon, carbon black, activated carbon, carbon fiber, fullerene or carbon nanotube, coke, etc. A single or a plurality of carbon materials are suitably used as the template material. If the temperature at which the carbon material is combusted is high, the pores collapse during gasification and the specific surface area of the catalyst decreases, but the graphite-based carbon material has a lower combustion temperature than other carbon materials, so it has excellent carbon. It can be suitably used as a material.

  If the particle size of the carbon material is too small, the average pore size of the catalyst that becomes a porous body after the calcination step becomes small, and the diffusion rate of synthesis gas mainly composed of carbon monoxide and hydrogen in the pores becomes slow. If the pore size is sufficiently larger than that of carbon monoxide having a large molecular structure among the components of the synthesis gas, hydrogen can easily enter the pores and the diffusion rate of the synthesis gas is increased. Conversely, as the size of the pores approaches that of carbon monoxide, hydrogen enters the pores, but carbon monoxide becomes difficult to enter the pores, and the diffusion rate of the synthesis gas decreases.

  When the particle size of the carbon material is too large, the specific surface area of the catalyst is reduced, and the contact between the synthesis gas and the metal exhibiting catalytic activity is reduced. In either case, there is a possibility that the improvement of the efficiency of the FT synthesis reaction is hindered. In order to obtain a sufficient specific surface area and avoid a decrease in the diffusion rate of the synthesis gas in the pores, it is preferable to use a carbon material having a minimum dimension in the range of 2 nm to 200 nm, and a carbon material in the range of 20 nm to 125 nm. More preferably, is used. The minimum dimension means the dimension of the minimum part of the shape with respect to various shapes of carbon materials including not only granular carbon materials but also acicular carbon materials. For example, it is a diameter for a spherical shape, a diameter of a needle portion for a needle shape, and a minimum one side dimension for a square column. A spherical shape is preferable in that it is easily dispersed. In addition, since a fine carbon material is difficult to handle, it may be granulated by adding water or the like, and may be handled with a maximum dimension of about 10 mm. When the carbon material thus granulated is stirred in the solution, the carbon material becomes the original small size and is dispersed, so there is no problem.

Also, if the specific surface area of the carbon material is small, the area of contact with oxygen in the air is limited in the firing process and it is difficult to burn, so that it remains in the catalyst that becomes a porous body as charcoal and closes the pores of the catalyst The specific surface area of the catalyst that becomes a porous body may be reduced. If the specific surface area of the carbon material is large, when the carbon material is gasified in the firing process, the catalytic activity that has entered the pores of the carbon material may be reduced. There is a possibility that the shape retaining property of the metal to be shown is lost and collapses, and the specific surface area of the catalyst that becomes a porous body is lowered. In the firing step without the carbon material remains, also the carbon material so as to ensure shape retention of the metal exhibiting a catalytic activity even gasified, a specific surface area ranging from 10m 2 ^/ g~2000m 2 ^{/ g} it is preferable to use a carbon ^material, it is more preferred to use carbon black in the range of 300m ² / g~1300m 2 / g range of activated carbon or ^{10m 2} / ^g~200m 2 / g. As a result, a porous catalyst having a large specific surface area and good quality can be obtained.

  Specifically, it is preferable to use carbon black or activated carbon as the carbon material. In general, when carbon black having the characteristics of a small specific surface area and a small particle size is used, a porous catalyst having a large specific surface area can be obtained. . In general, when activated carbon having a feature of being a porous body and having a large specific surface area is used, a metal exhibiting catalytic activity that has entered the pores of the activated carbon can ensure shape retention even when the activated carbon is gasified in the firing step. In any case, a good porous catalyst having a large specific surface area can be obtained. Some carbon materials are made from plants, coal, and petroleum. Among them, it is preferable to use carbon materials made from plants that have few impurities that hinder the activity of the catalyst.

  If the amount of the carbon material that is the template material is too large, the carbon material aggregates in the solution and a good carbon dispersion solution cannot be obtained. When such a carbon dispersion solution is baked, the carbon material is concentrated and excessively burned locally, resulting in a high temperature, and the pores generated in the catalyst may collapse and the specific surface area may decrease. If the added amount of the carbon material is too small, the pores generated in the catalyst are reduced even when the carbon material is combusted and gasified, and a porous body having a large specific surface area cannot be obtained in the firing step. In order to obtain a catalyst that becomes a porous body having a large specific surface area, the carbon material added in the carbon dispersion solution generation step is set in a range of 0.1 wt% to 70 wt% with respect to the weight of the water-soluble salt. It is preferable that it is set in the range of 5 wt% to 40 wt%.

  The carbon dispersion solution is preferably baked in a temperature range of 423K to 900K in the baking step, and more preferably baked in a temperature range of 523K to 773K. When calcined in this temperature range, a catalyst that becomes a good porous body can be obtained without breaking the pores generated by gasification of the carbon material at the time of calcining.

A hydrocarbon production method for synthesizing hydrocarbons from carbon monoxide and hydrogen by an FT synthesis reaction using the FT synthesis catalyst produced through the above-described steps will be described.
The hydrocarbon production process consists of a synthesis gas production process that produces carbon monoxide and hydrogen by decomposing solid biomass and coal, or natural gas that is a gas, and synthesis that consists of the produced carbon monoxide and hydrogen. FT synthesis reaction step of synthesizing hydrocarbons by supplying FT synthesis reaction under specified pressure and temperature conditions by supplying gas as a raw material gas to a fixed bed, fluidized bed, slurry bed or the like charged with an FT synthesis catalyst Including.

Prior to the FT synthesis reaction step, it is necessary to reduce and activate the FT synthesis catalyst in advance, and the fixed bed, fluidized bed, slurry bed, etc. in which the FT synthesis catalyst is charged contain carbon monoxide. A catalyst activation treatment is required in which a reactive gas is supplied and the catalyst for FT synthesis and the reducing gas are brought into contact with each other at, for example, 423K to 673K for several hours. For example, when iron oxide Fe ₂ O ₃ is used as a catalyst for FT synthesis, iron carbide Fe ₂ C ₅ is generated on the surface of iron oxide Fe ₂ O ₃ by the catalyst activation treatment, and this iron carbide Fe ₂ C ₅ is activated. It becomes.

  In the FT synthesis reaction step, synthesis gas carbon monoxide is adsorbed on the catalyst, oxygen is separated, and carbon and hydrogen are combined. Oxygen separated from carbon reacts with hydrogen to produce water.

  When using the FT synthesis catalyst produced by the method for producing an FT synthesis catalyst according to the present invention, carbon monoxide and hydrogen are reacted under pressure conditions of 0.5 MPa to 5 MPa and temperature conditions of 423 K to 673 K. Thus, hydrocarbons are efficiently synthesized.

Examples will be described below. Ferric nitrate nonahydrate [Fe (H ₂ O) ₆ ] (NO ₃ ) ₃ · 3H ₂ O as a water-soluble metal salt showing catalytic activity of FT synthesis reaction, 8 to 16 g as sulfuric acid catalyst Copper CuSO ₄ (0.4 g to 4.8 g) and potassium nitrate KNO ₃ (0.01 g to 0.8 g) were weighed, and dissolved in ethylene glycol or water (10 ml to 20 ml) as a solvent.

  Activated carbon or carbon black as a carbon material was added to the solution in a range of 3 wt% to 90 wt% based on the weight of ferric nitrate nonahydrate, and mixed by stirring to obtain a carbon dispersion solution. .

  Furthermore, each carbon dispersion solution was calcined in a temperature range of 623 K to 923 K for 1 hour to 12 hours, and the carbon material was gasified and removed to obtain a porous catalyst. FIG. 2 shows the production conditions and specific surface area of the obtained catalyst, and shows the carbon monoxide conversion rate according to the elapsed time of the FT synthesis reaction indicating the performance of each catalyst. In FIG. 2, the solvent EG indicates ethylene glycol, and the average value of carbon monoxide conversion is an average value of reaction times of 6 hours to 9 hours. Sample No. Reference numerals 1 and 2 are comparative samples manufactured without using a carbon material.

  In addition, you may stand still for a predetermined time before baking a carbon dispersion solution, and you may perform the drying process which vaporizes a solvent before baking.

  The specific surface area of each catalyst is a value measured with a specific surface area measuring device (NOVA1000 (manufactured by Quantachrome Instruments)). Also, using an autoclave reactor, a synthesis gas having a composition ratio of 1 (H2 / CO = 1) is supplied under the conditions of W / F = 5 g · h / mol to 10 g · h / mol, and the reaction pressure The catalytic activity was evaluated by the carbon monoxide conversion rate (also referred to as “CO conversion rate”) for each elapsed time when the FT synthesis reaction was performed at 1 MPa and a reaction temperature of 423 K to 673 K. Here, W is the weight of the catalyst, and F is the flow rate of the synthesis gas.

  As shown in FIG. 2, the specific surface area is larger when the calcination temperature is lower than when the calcination temperature is higher, the catalyst produced without the addition of the cocatalyst has low catalytic activity, and is higher by adding the cocatalyst. Exhibiting catalytic activity (Sample Nos. 4 and 5) When performing a filtration step of filtering the carbon dispersion solution before firing, the specific surface area after firing is small and the catalytic activity is reduced, but the filtration step is not performed. In some cases, it has been found that a catalyst having a large specific surface area and high catalytic activity can be obtained. That is, it has been found that it is better not to perform a filtration step of filtering the carbon dispersion solution before firing.

Furthermore, if the amount of carbon black added is large, the specific surface area becomes larger than when it is small, the specific surface area is 45 m ² / g or more, the CO conversion is 80% or more, and water is used as the solvent. It was also found that the characteristics did not change greatly even when alcohol (ethylene glycol) or ketone solution was used.

  FIG. 3 shows the relationship between the carbon material addition amount and the specific surface area. Sample No. 2 was added in which the cocatalyst (Cu, K) was added, the filtration step was not performed, and the calcination temperature was 673K. 2, 9, 10, 14, 15, 20, 21, and 23.

When the added amount of the carbon material is 70% by weight or more, the carbon material becomes excessive with respect to the water-soluble salt, and the excessive carbon material is excessively burned locally during the firing process, resulting in a high temperature and reducing the specific surface area. Become. Moreover, when the addition amount of the carbon material is 35% by weight or more of the solvent, it is difficult to disperse the carbon material, and when it is 60% by weight or more, the aqueous solution becomes undesirably clayy. If it becomes difficult to disperse the carbon material, local excessive combustion occurs during the firing step, resulting in a high temperature and a reduction in the specific surface area. In order to obtain a porous catalyst having a specific surface area of about 45 m ² / g, the amount of carbon material added is preferably set in the range of 0.1 wt% to 70 wt%, and 5 wt% to 40 wt%. More preferably, it is set in the range of%.

  FIG. 4 shows the relationship between the calcination temperature and the specific surface area of the catalyst. Sample No. The characteristics are based on 4, 9, 11, 12, 13, 14, 16, 22, and 23.

In order to obtain a specific surface area of 45 m ² / g or more, it is necessary to set the reaction temperature (423 K) as the lower limit and the firing temperature to 900 K or less, and a range of 523 K to 773 K is more preferable.

FIG. 5 shows the relationship between the catalyst specific surface area and the catalyst activity (carbon monoxide conversion). Sample No. The characteristics are based on 2, 4, 5, 10, 14, 16, 23. In order to obtain a carbon monoxide conversion rate of 80% or more, the specific surface area needs to be 45 m ² / g or more.

FIG. 6A shows the relationship between the particle diameter of the carbon material and the specific surface area. Sample No. It is the characteristic based on 15-20. In order to obtain a catalyst having a specific surface area of 45 m ² / g or more, the upper limit of the particle diameter of the carbon material is preferably 200 nm. As a result of the inventors' knowledge, when a fine carbon material of 2 nm or less is used, the ratio of the pore diameter of the porous catalyst to micropores (2 nm or less) increases, and the synthesis gas diffuses in the pores. Therefore, the lower limit of the particle diameter of the carbon material is preferably 2 nm.

FIG. 6B shows the relationship between the specific surface area of the carbon material and the specific surface area of the catalyst. Sample No. It is a characteristic based on 6-9 and 15-20. To obtain a 45 m ² / g or more specific surface area of the catalyst, the specific surface area of the carbon material used in the ^template, it is preferably in the range of 10m ² / g~2000m 2 / g. In the case of using the activated carbon as the carbon material, although the specific surface area of the carbon material is in the range of from about 500m ² / g~2000m ² / g, a specific surface area of ^{10 m} 2 / g approximately carbon black also included within the above range is preferred .

  In the above-described embodiment, an example in which water or ethylene glycol is used as the solvent has been described. However, similar results can be obtained by using another alcohol or ketone solution instead of ethylene glycol.

  In the above-described embodiment, an example in which ferric nitrate is used as the iron-based catalyst has been described. However, a hydrate of ferric nitrate may be used. Similar results can be obtained using cobalt-based, nickel-based, and ruthenium-based catalysts.

In the above-described embodiment, an example in which copper and potassium are used as promoters has been described. However, similar results can be obtained by using other promoters already listed.

Claims (13)

A carbon dispersion solution generating step of dissolving a water-soluble salt or complex of a metal exhibiting catalytic activity of a fuel synthesis reaction and a promoter in water, an alcohol solution or a ketone solution, and dispersing a carbon material in the solution;
By firing the carbon dispersion solution obtained in the carbon dispersion solution production step, a firing step of removing the carbon material and producing the metal oxide,
The manufacturing method of the catalyst for fuel synthesis containing this.   The water-soluble salt used in the carbon dispersion solution generating step is a compound of any one of iron, cobalt, nickel or ruthenium and an inorganic acid or an organic acid exhibiting a catalytic activity for a fuel synthesis reaction. A method for producing a catalyst for fuel synthesis.   3. The fuel according to claim 1, wherein the carbon material used in the carbon dispersion solution generation step is a single or a plurality of carbon materials selected from any of carbon materials having a hexagonal network surface of carbon atoms as a basic structure. A method for producing a catalyst for synthesis.   The method for producing a fuel synthesis catalyst according to any one of claims 1 to 3, wherein the carbon material used in the carbon dispersion solution generation step is a carbon material having a minimum dimension in a range of 2 nm to 200 nm. Carbon material used in the carbon dispersion solution generating step has a specific surface area of 10m 2 ^/ g~2000m 2 ^{/ g} range claim 1 wherein the carbon material of the catalyst for fuel synthesis according to claim 4 of the Production method.   The method for producing a fuel synthesis catalyst according to claim 4 or 5, wherein the carbon material used in the carbon dispersion solution generation step is carbon black or activated carbon.   The amount of the carbon material used in the carbon dispersion solution generation step is set in a range of 0.1 wt% to 70 wt% with respect to the weight of the water-soluble salt. A method for producing the catalyst for fuel synthesis as described.   The carbon material according to any one of claims 3 to 7, wherein a carbon material is added in a range of 0.2 mg to 1 g with respect to 1 ml of a solvent that dissolves a water-soluble salt or complex of a metal exhibiting a catalytic activity of a fuel synthesis reaction. A method for producing a catalyst for fuel synthesis as described in 1.   The method for producing a fuel synthesis catalyst according to any one of claims 1 to 8, wherein the calcination step is performed at a calcination temperature in a range of 423K to 900K.   The promoter includes alkali metal elements, alkaline earth elements, rare earth elements, noble metal elements, copper (Cu), titanium (Ti), zirconium (Zr), molybdenum (Mo), manganese (Mn), and vanadium (V). The method for producing a catalyst for fuel synthesis according to any one of claims 1 to 9, wherein the catalyst is a single or a plurality of promoters selected from any one of them.   11. The fuel synthesis composition according to claim 10, wherein an addition amount of the co-catalyst added in the carbon dispersion solution generation step is set in a range of 0.1 wt% to 30 wt% with respect to the weight of the water-soluble salt. A method for producing a catalyst. A fuel synthesis catalyst produced by the method for producing a fuel synthesis catalyst according to claim 1 and having a specific surface area of 45 m ² / g or more.   Carbon monoxide under pressure conditions of 0.5 MPa to 5 MPa and temperature conditions of 423 K to 673 K using the fuel synthesis catalyst produced by the method for producing a fuel synthesis catalyst according to claim 1. Of hydrocarbons by synthesizing hydrocarbons by reacting hydrogen with hydrogen.

Images