WO2009154099A1

WO2009154099A1 - Fischer-tropsch synthesis catalyst, method for producing the same, and method for producing hydrocarbons using the catalyst

Info

Publication number: WO2009154099A1
Application number: PCT/JP2009/060480
Authority: WO
Inventors: 一仁佐藤; 茂徳中静
Original assignee: コスモ石油株式会社
Priority date: 2008-06-17
Filing date: 2009-06-08
Publication date: 2009-12-23
Also published as: JP2010023022A

Abstract

Disclosed is an FT synthesis catalyst which exhibits higher activity and high CO conversion rate in an FT process, thereby enabling a stable FT synthesis reaction. The FT synthesis catalyst can improve productivity of hydrocarbons. A method for producing the FT synthesis catalyst and a method for producing hydrocarbons using the FT synthesis catalyst are also disclosed. Specifically disclosed is a Fischer-Tropsch synthesis catalyst which contains, in an inorganic oxide carrier, 10-50% by mass of manganese in terms of Mn₂O₃ based on the catalyst, 0.5-5% by mass of ruthenium in terms of metal based on the catalyst, and 5-30% by mass of cobalt in terms of metal based on the catalyst. A method for producing the catalyst and a method for producing hydrocarbons using the catalyst are also disclosed.

Description

Fischer-Tropsch synthesis catalyst, method for producing the same, and method for producing hydrocarbons using the catalyst

The present invention relates to a Fischer-Tropsch synthesis catalyst for producing hydrocarbons from a mixed gas containing hydrogen and carbon monoxide as main components (hereinafter referred to as “synthesis gas”), and a method for producing the catalyst. Furthermore, the present invention relates to a method for producing hydrocarbons such as naphtha, kerosene, light oil, and wax by contacting the catalyst with synthesis gas.

As methods for synthesizing hydrocarbons from synthesis gas, Fischer-Tropsch reaction (Fischer-Tropsch reaction), methanol synthesis reaction, C ₂ oxygen-containing (ethanol, acetaldehyde, etc.) synthesis reaction, etc. are well known. It is known that Fischer-Tropsch reaction proceeds with platinum group catalysts such as iron and cobalt, iron group, ruthenium, etc., methanol synthesis reaction with copper catalyst, and C ₂ oxygen-containing synthesis reaction with rhodium catalyst. In addition, it is known that the catalytic ability of the catalyst used in the synthesis of these hydrocarbons is strongly related to the dissociative adsorption ability of carbon monoxide (see, for example, Non-Patent Document 1).

By the way, in recent years, gas oil with low sulfur content has been desired from the viewpoint of air environment conservation, and it is considered that this trend will become stronger in the future. In addition, from the viewpoint that crude oil resources are limited and from the viewpoint of energy security, the development of alternative fuels for oil is desired, and it is expected that this will become increasingly desirable in the future. GTL (gas to liquids) is a technology that synthesizes liquid fuels such as kerosene from natural gas (main component methane), which is said to have recoverable reserves equivalent to crude oil in terms of energy. is there.

Since natural gas does not contain sulfur or is hydrogen sulfide (H ₂ S) or the like that is easy to desulfurize even if it contains, liquid fuel such as kerosene obtained has almost no sulfur in it. In addition, because of the advantage that it can be used for high-performance diesel fuel having a high cetane number, this GTL has been increasingly attracting attention in recent years.

As a part of the GTL, a method for producing hydrocarbons from synthesis gas by a Fischer-Tropsch reaction (hereinafter referred to as “FT reaction”) (hereinafter referred to as “FT method”) has been actively studied. In this FT method, in order to increase the yield of hydrocarbons, it is considered effective to use a catalyst having excellent performance such as high production capacity of hydrocarbons, that is, high activity and stable activity for a long time. It is done.

Conventionally, various catalysts for FT reaction have been proposed. As a catalyst for high selectivity to olefins, a catalyst in which ruthenium is supported on a manganese oxide support, and further this ruthenium supported catalyst. Ruthenium-based catalysts such as catalysts added with a third component (for example, see Patent Document 1 and Patent Document 2), ruthenium-based catalysts using alumina having a specific pore structure as a support (for example, see Patent Document 3) Proposed.

Japanese Patent Publication No. 3-70691 Japanese Patent Publication No. 3-70692 Japanese Unexamined Patent Publication No. 2005-238014

These ruthenium-based catalysts have correspondingly excellent selectivity for olefins and show corresponding catalytic activity in the FT method using the same, but further improvement in catalytic activity is desired. In general, the higher the activity of the catalyst, the higher the productivity of the target product per catalyst weight, and the smaller the amount of catalyst used to obtain the same amount of target product, the smaller the reactor cost. And equipment costs can be reduced.

In view of the above-described conventional situation, the present invention is able to perform FT synthesis reaction with higher activity, higher CO conversion rate, and higher stability in the FT method, and improve the productivity of hydrocarbons. An object of the present invention is to provide a catalyst for FT synthesis, a method for producing the same, and a method for producing hydrocarbons using the catalyst.

The inventors of the present invention have intensively studied to achieve the above object. As a result, a catalyst in which a specific amount of three kinds of metal components, manganese, cobalt, and ruthenium, is contained in an inorganic oxide support, The present invention was completed by finding that the activity was greatly improved as compared with a catalyst containing one or two of them alone.

That is, this invention provides the catalyst for FT synthesis of the following structures, its manufacturing method, and the manufacturing method of hydrocarbons using the same.
(1) Inorganic oxide carrier, manganese as catalyst standard, 10-50% by mass in terms of Mn ₂ O ₃ , ruthenium as catalyst standard, 0.5-5% by mass in terms of metal, cobalt as catalyst standard, in terms of metal A Fischer-Tropsch synthesis catalyst characterized by containing 5 to 30% by mass.
(2) The Fischer-Tropsch synthesis catalyst according to (1) above, wherein the inorganic oxide support is silica or alumina.
(3) The Fischer-Tropsch synthesis catalyst according to (1) or (2) above, wherein the inorganic oxide support has a spherical shape.
(4) Manganese is contained in the inorganic oxide support so that the content is 10 to 50% by mass in terms of catalyst, converted to Mn ₂ O ₃ , and cobalt is contained in 5 to 5% in terms of catalyst based on catalyst. A catalyst precursor is prepared by containing 30% by mass, drying, and then calcining at 300 to 700 ° C., and ruthenium is contained in the catalyst precursor in an amount of 0.5 in terms of metal based on the catalyst. A process for producing a Fischer-Tropsch synthesis catalyst, characterized by comprising -5% by mass and then drying at a temperature of 200 ° C or lower.
(5) A method for producing hydrocarbons, comprising contacting the catalyst according to any one of (1) to (3) above with a gas mainly composed of hydrogen and carbon monoxide.

The catalyst of the present invention in which manganese, cobalt and ruthenium coexist can significantly improve the CO conversion rate compared to a catalyst containing these components alone or in any one of two types. The productivity of hydrogen is high and the activity is high, so that the catalyst cost and the reactor size can be expected to be reduced.

The detailed mechanism of catalytic activity improvement by coexistence of manganese, cobalt, and ruthenium has not been clarified, but the activity improvement that cannot be explained by the simple additivity of ruthenium and cobalt, which are active metal species, for the FT reaction Is observed, and manganese which does not show activity in the FT reaction is also an essential component, so it is presumed that it is due to the combined effect of these components.

The present invention is described in detail below.
The catalyst of the present invention can be obtained by containing manganese and cobalt in an inorganic oxide carrier, drying and calcining, and then containing ruthenium and drying. Hereinafter, the catalyst of the present invention and the preparation method thereof to the production method of hydrocarbons using the same will be sequentially described.

<Catalyst and its preparation method>
In the catalyst of the present invention, as the inorganic oxide carrier, silica, alumina, titania, zirconia, or a composite oxide thereof is used alone or in combination, and among these, silica and alumina are preferable. Silica can be prepared by a conventionally known method. For example, silica sol prepared from water glass (sodium silicate) can be dried and fired. It can also be obtained from decomposition of silicates or decomposition of silicon tetrachloride or ethyl silicate.

Further, as examples of alumina, those in various crystal states such as α, β, γ, η, θ, or hydrates of aluminum oxides such as dibsite, bayerite, boehmite can be used. These aluminum oxides can be produced by a conventionally known method, and can be obtained, for example, by thermal decomposition of the hydrate of the aluminum oxide. Aluminum oxide hydrates can be obtained by hydrolysis or thermal decomposition of various aqueous aluminum salt solutions such as aluminum chloride, aluminum nitrate, aluminum sulfate, and alkali aluminate.

Alumina (especially γ-alumina) obtained by calcining low crystallinity such as boehmite calcinates aluminum oxide hydrate containing many high crystallinity such as vialite and dibside. It is preferable because the specific surface area and pore volume are larger than the alumina obtained. Furthermore, alumina obtained by a sol-gel method for hydrolyzing an aluminum alkoxide such as aluminum isopropoxide can also be preferably used because of its large specific surface area and pore volume.

The specific surface area, pore volume, pore diameter and shape of the inorganic oxide support are not particularly limited, but the specific surface area is generally 20 to 300 m ² / g, preferably 30 to 250 m ² / g, more preferably 40. ~ 200 m ² / g. It is preferable that the specific surface area of the inorganic oxide carrier is 20 m ² / g or more because each component is well dispersed when an active metal component such as manganese, ruthenium, and cobalt is contained thereafter.

Further, the pore volume of the inorganic oxide support is generally, 0.1 ~ 1.2cm ³ / g, preferably 0.2 ~ 1.1cm ³ / g, more preferably 0.3 ~ 1.0 cm ³ / g. By setting the pore volume to 0.1 cm ³ / g or more, the dispersibility of the active metal component can be maintained as described above. The upper limit of the pore volume is preferably 1.2 cm ³ / g or less from the viewpoint of production technology, while maintaining the mechanical strength of the catalyst, suppressing the occurrence of catalyst pulverization during the reaction, and the like. .

Furthermore, the pore diameter of the inorganic oxide carrier is about 5 to 60 nm, but is generally 8 nm or more, preferably 10 nm or more, more preferably 16 nm or more. A pore diameter of 8 nm or more is preferable because the diffusion of higher hydrocarbons such as wax produced by the FT reaction to the outside of the pores and the diffusion of the synthesis gas as the raw material gas into the pores are sufficient.

The shape of the inorganic oxide support is preferably spherical. The type of FT reaction using the catalyst of the present invention will be described later. When the reaction is performed in the form of a slurry bed, the catalyst flows in a suspended state in the reactor. When the catalyst particle shape is uneven, there is a high possibility that fine particles will be generated by contact between the catalysts or contact between the catalyst and the reactor inner wall. When the particle shape of the catalyst is spherical, the generation of such fine powder tends to be suppressed. The spherical inorganic oxide carrier may be prepared by a conventionally known method, for example, a method in which silica sol or alumina sol is dropped into an oil phase and spheroidized by surface tension, or a method in which silica sol or alumina sol is spheroidized and dried by a spray dryer. Also known is a method in which an aqueous solution containing silica sol or alumina sol and an organic solvent are emulsified and then gelled.

Incorporation of manganese and cobalt into the inorganic oxide support can be appropriately performed by, for example, a normal impregnation supporting method. For example, an inorganic oxide carrier can be impregnated with an aqueous solution of a manganese salt, dried and fired, then the fired product is impregnated with an aqueous solution of a cobalt salt, dried again, and then fired. Alternatively, an aqueous solution containing both a manganese salt and a cobalt salt can be prepared, impregnated with manganese and cobalt at the same time, dried and then fired, or each can be impregnated separately and dried. It may be fired. Further, the order of impregnation of manganese and cobalt is not particularly limited, and the method for supporting impregnation of manganese and cobalt is not particularly limited.

In addition, manganese and cobalt can be contained in the inorganic oxide carrier by, for example, preparing a slurry containing the inorganic oxide carrier and manganese salt or cobalt salt, spray drying with a spray dryer, and then firing. It is.

Furthermore, the inclusion of manganese and cobalt in the inorganic oxide support may be performed by combining the above impregnation and spraying. For example, a slurry containing an inorganic oxide carrier and a manganese salt can be spray-dried with a spray dryer, then fired, then the fired product is impregnated with an aqueous solution of cobalt salt, dried again, and then fired. . At this time, there is no particular problem even if the order of manganese and cobalt is reversed.

Examples of the manganese salt include manganese nitrate, manganese chloride, and manganese acetate. Examples of the cobalt salt include cobalt nitrate, cobalt chloride, cobalt sulfate, and cobalt acetate. These are usually dissolved in water to form an aqueous solution. Used as In view of solubility in water, manganese nitrate is preferably used as the manganese salt, and cobalt chloride or cobalt nitrate is preferably used as the cobalt salt.

The manganese content in the catalyst of the present invention is 10 to 50% by mass, preferably 10 to 40% by mass, more preferably 15 to 30% by mass in terms of catalyst, based on Mn ₂ O ₃ (manganese oxide). By making the ratio of the manganese oxide in the catalyst within the above range, the activity can be further improved. That is, by setting the content of manganese oxide to 10% by mass or more, generation of gas components can be further suppressed, and further the yield of liquid hydrocarbons can be increased. Moreover, the fall of the specific surface area and pore volume of a catalyst can be suppressed by content of manganese oxide being 50 mass% or less.

In addition, the cobalt content is 5 to 30% by mass, preferably 5 to 25% by mass, more preferably 5 to 20% by mass in terms of metal based on the catalyst. By making the content of cobalt 5% by mass or more, a remarkable activity improvement effect of cobalt as an active metal is recognized. Moreover, by setting it as 30 mass% or less, it is possible to suppress the aggregation of cobalt under the drying step, the firing treatment step in the catalyst preparation, and the reaction conditions when subjected to the FT reaction, and the FT reaction. The improvement in the gas yield in the product in can be suppressed.

In preparing the catalyst of the present invention, the contents of manganese and cobalt in the inorganic oxide support are adjusted so that the contents of manganese and cobalt in the catalyst of the present invention are in the above ranges. Next, the inorganic oxide support containing manganese and cobalt is dried and then calcined to obtain a catalyst precursor. The drying at this time is in principle performed to evaporate water, and the temperature is preferably 100 to 200 ° C., and the time is preferably 1 to 10 hours.

The firing is generally performed at a temperature of 300 to 700 ° C., preferably 400 to 600 ° C. By setting the calcination temperature to 700 ° C. or lower, it is possible to suppress a decrease in the specific surface area of the carrier and to agglomerate the supported components. By setting the calcination temperature to 300 ° C. or higher, oxide formation and carrier stability are maintained. be able to. From the same viewpoint, the firing time is preferably 2 to 10 hours.

As described above, manganese and cobalt are contained in the inorganic oxide support, followed by drying and calcining treatment, and then the catalyst precursor obtained is made to contain ruthenium.

The content of ruthenium in the catalyst of the present invention is 0.5 to 5% by mass, preferably 0.8 to 4.5% by mass, more preferably 1 to 4% by mass in terms of metal on a catalyst basis. The ruthenium content is related to the number of active sites. By setting the content of ruthenium to 0.5% by mass or more, the number of active sites is maintained and sufficient catalytic activity can be obtained. Further, by setting the ruthenium content to 5% by mass or less, it is possible to suppress ruthenium remaining without being supported on the carrier, and to reduce ruthenium dispersibility and to express ruthenium species having no interaction with the carrier component. This can be suppressed. The chemical composition of these catalysts can be determined by inductively coupled plasma mass spectrometry (ICP method).

Regarding the method for containing ruthenium in the catalyst precursor obtained as described above, for example, a normal impregnation method in which the catalyst precursor is immersed in a solution of a ruthenium compound, or a ruthenium compound is adsorbed on the catalyst precursor. It can be carried out by ion exchange and deposition, or by adding a precipitating agent such as alkali. At this time, the ruthenium content is adjusted to be a predetermined amount in the catalyst of the present invention.

As the ruthenium compound, various ruthenium compounds conventionally used for the preparation of ruthenium-supported catalysts can be appropriately selected and used. Preferred examples thereof include water-soluble ruthenium salts such as ruthenium chloride, ruthenium nitrate, ruthenium acetate and hexaammonium ruthenium, and ruthenium compounds soluble in organic solvents such as ruthenium carbonyl and ruthenium acetylacetonate.

After containing ruthenium, a drying process is performed to remove solvent such as moisture. The drying temperature at this time is preferably 200 ° C. or lower, more preferably 150 ° C. or lower, from the temperature at which moisture or the like evaporates. By setting the drying temperature to 200 ° C. or lower, it is possible to suppress ruthenium aggregation and ruthenium from becoming a RuO ₄ peroxide and volatilizing. Moreover, the possibility of volatilization of ruthenium can be further reduced by setting the atmosphere during drying to an inert gas atmosphere such as nitrogen or helium instead of air. From the same viewpoint, the drying time is preferably 1 to 10 hours.

In the catalyst of the present invention, the specific surface area is generally 20 to 300 m ² / g, preferably 30 to 250 m ² / g, more preferably 40 to 200 m ² / g. By making the specific surface area 20 m ² / g or more, the dispersibility of ruthenium can be maintained. Regarding the upper limit of the specific surface area, in general, when handling a solid catalyst, the larger the frequency, the higher the gas-liquid solid contact frequency. However, in the present invention, the upper limit of the specific surface area is preferably 300 m ² / g or less.

Further, the pore volume of the catalyst of the present invention is generally, 0.1 ~ 1.2cm ³ / g, preferably 0.2 ~ 1.1cm ³ / g, more preferably 0.3 ~ 1.0 cm ³ / g. By making the pore volume 0.1 cm ³ / g or more, the dispersibility of the active metal species can be maintained. Further, the upper limit of the pore volume is to keep the mechanical strength of the catalyst, to prevent the catalyst from being pulverized during the reaction, and to be 1.2 cm ³ / g or less from the viewpoint of production technology. Is preferred.

<Method for producing hydrocarbons>
The method for producing hydrocarbons of the present invention is carried out by subjecting the catalyst of the present invention prepared as described above to the FT reaction, that is, contacting the catalyst mainly with hydrogen and carbon monoxide. Is called. In the method for producing hydrocarbons of the present invention, the type of the reactor for the FT reaction includes a fixed bed, a fluidized bed, a suspension bed, a slurry bed, and the like, and is not particularly limited. Next, a method for producing the hydrocarbons of the present invention using a slurry bed will be described.

When the method for producing the hydrocarbons of the present invention is performed in a slurry bed, the shape of the catalyst is preferably spherical, and the preferred range for the catalyst particle distribution is 1 μm or more and 150 μm or less, more preferably 5 μm or more and 120 μm or less, Most preferably, it is 10 μm or more and 110 μm or less. In the case of a slurry bed reaction type, the catalyst is used by dispersing in a liquid hydrocarbon or the like, and by setting it to 1 μm or more, the outflow of catalyst particles to the downstream side due to particles being too fine is suppressed, and the reaction It is possible to suppress a decrease in the catalyst concentration in the container and to prevent the downstream device from being damaged by the catalyst fine particles. Moreover, by setting it as 150 micrometers or less, the catalyst particle is not disperse | distributed in the whole reaction container, but the fall of the reaction activity by slurry becoming non-uniform | heterogenous can be suppressed. The spherical shape of the catalyst with no irregularities reduces the generation of fine particles due to catalyst cracking or pulverization due to contact between the catalysts or contact between the catalyst and the inner wall of the reactor in the slurry bed reaction mode. Therefore, it is preferable.

In the method for producing hydrocarbons of the present invention, the catalyst of the present invention prepared as described above is subjected to reduction treatment (activation treatment) in advance before being subjected to the FT reaction. By this reduction treatment, the catalyst is activated so as to exhibit a desired catalytic activity in the FT reaction. When this reduction treatment is not performed, the ruthenium species supported on the support is not sufficiently reduced and does not exhibit the desired catalytic activity in the FT reaction.

This reduction treatment is preferably performed by a method in which the catalyst is brought into contact with the reducing gas in a slurry state dispersed in liquid hydrocarbons, or a method in which the reducing gas is simply vented and brought into contact with the catalyst without using hydrocarbons. it can. As the liquid hydrocarbons in which the catalyst is dispersed in the former method, various liquids such as olefins, alkanes, alicyclic hydrocarbons, and aromatic hydrocarbons can be used as long as they are liquid under the processing conditions. Hydrocarbons can be used. Further, it may be a hydrocarbon containing a hetero element such as oxygen-containing or nitrogen-containing. The number of carbons of these hydrocarbons is not particularly limited as long as they are liquid under the treatment conditions, but generally those of C6 to C40 are preferred, those of C9 to C40 are more preferred, and those of C9 to C35 are preferred. Is most preferred. If it is heavier than C6 hydrocarbons, the vapor pressure of the solvent will not be too high, and the processing condition range will not be limited. Moreover, if it is lighter than C40 hydrocarbons, the solubility of reducing gas will not fall and sufficient reduction | restoration processing can be performed.

In addition, the amount of catalyst dispersed in the hydrocarbons during the reduction treatment is appropriately 1 to 50% by mass, preferably 2 to 40% by mass, more preferably 3 to 30% by mass. If the amount of catalyst is 1% by mass or more, it is possible to prevent the reduction efficiency of the catalyst from being excessively lowered. Therefore, as a method to prevent a reduction in the reduction efficiency of the catalyst, it is possible to reduce the flow rate of the reducing gas and avoid the loss of dispersion of gas (reducing gas) -liquid (solvent) -solid (catalyst). can do. A catalyst amount of 50% by mass or less is preferable because the viscosity of the slurry in which the catalyst is dispersed in hydrocarbons does not become too high, the bubble dispersion is good, and the catalyst is sufficiently reduced.

Further, the treatment temperature of this reduction treatment is preferably 140 to 250 ° C., more preferably 150 to 200 ° C., and most preferably 160 to 200 ° C. If it is 140 degreeC or more, ruthenium will fully be reduce | restored and sufficient reaction activity will be obtained. If the temperature is 250 ° C. or lower, a phase transition of manganese oxide in the catalyst, a change in oxidation state, etc. proceed to form a complex with ruthenium, which causes the catalyst to sinter. Therefore, the possibility of causing a decrease in activity can be avoided.

For this reduction treatment, a reducing gas mainly containing hydrogen is preferably used. The reducing gas to be used may contain a certain amount of components other than hydrogen, for example, water vapor, nitrogen, rare gas, etc. within a range that does not hinder the reduction.

The reduction treatment is influenced by the hydrogen partial pressure and the treatment time as well as the treatment temperature, but the hydrogen partial pressure is preferably 0.1 to 10 MPa, more preferably 0.5 to 6 MPa, and 1 to 5 MPa. Is most preferred. If the hydrogen partial pressure is 0.1 MPa or more, the reduction of ruthenium proceeds sufficiently and is activated. Moreover, if it is 10 Mpa or less, it is preferable because the processing cost can be reduced without requiring meaningless high-pressure conditions for activation. The reduction treatment time varies depending on the catalyst amount, the hydrogen aeration amount, etc., but is generally preferably 0.1 to 72 hours, more preferably 1 to 48 hours, and most preferably 4 to 48 hours. When the treatment time is 0.1 hour or longer, the activation of the catalyst is prevented from becoming insufficient. Moreover, if it is 72 hours or less, the inconvenience such as an increase in the processing cost can be avoided even though the catalyst performance is not improved by the meaningless long-time reduction treatment.

In the method for producing hydrocarbons of the present invention, the catalyst of the present invention reduced as described above is used for the FT reaction, that is, the hydrocarbon synthesis reaction.
The FT reaction in the method for producing hydrocarbons of the present invention is in a dispersed state in which a catalyst is dispersed in liquid hydrocarbons, and a synthesis gas comprising hydrogen and carbon monoxide is brought into contact with the dispersed catalyst. At this time, as the hydrocarbons in which the catalyst is dispersed, the same hydrocarbons used in the reduction treatment performed in advance can be used. That is, various hydrocarbons including olefins, alkanes, alicyclic hydrocarbons, aromatic hydrocarbons can be used as long as they are liquid under the reaction conditions, including oxygen, nitrogen, etc. It may be a hydrocarbon containing a hetero element. The number of carbon atoms need not be particularly limited, but is generally preferably C6 to C40, more preferably C9 to C40, and most preferably C9 to C35. If it is heavier than C6 hydrocarbons, the vapor pressure of the solvent will not be too high, and the reaction condition range will not be limited. Moreover, if it is lighter than C40 hydrocarbons, it is possible to avoid a decrease in the reaction activity without lowering the solubility of the raw material synthesis gas. In the reduction treatment performed in advance, in the case where a method in which the catalyst is dispersed in liquid hydrocarbons is employed, the liquid hydrocarbons used in the reduction treatment can be used as they are in this FT reaction.

The amount of catalyst dispersed in the hydrocarbons in the FT reaction is generally 1 to 50% by mass, preferably 2 to 40% by mass, more preferably 3 to 30% by mass. If the catalyst amount is 1% by mass or more, the activity of the catalyst is insufficient, and in order to make up for the lack of activity, the aeration amount of the synthesis gas is decreased, and the gas (synthesis gas) is reduced by the decrease in the aeration amount of the synthesis gas. ) -Liquid (solvent) -solid (catalyst) dispersion can be avoided. Further, if the amount of catalyst is 50% by mass or less, it is possible to avoid that the viscosity of the slurry in which the catalyst is dispersed in hydrocarbons becomes too high, resulting in poor bubble dispersion and insufficient reaction activity. .

The synthesis gas used for the FT reaction only needs to contain hydrogen and carbon monoxide as main components, and other components that do not interfere with the FT reaction may be mixed. Further, since the rate (k) of the FT reaction depends on the first order of the hydrogen partial pressure, it is desirable that the partial pressure ratio of hydrogen and carbon monoxide (H ₂ / CO molar ratio) is 0.6 or more. Since this reaction is a reaction accompanied by volume reduction, it is preferable that the total value of the partial pressures of hydrogen and carbon monoxide is higher. The upper limit of the partial pressure ratio of hydrogen and carbon monoxide is not particularly limited, but a practical range of this partial pressure ratio is suitably 0.6 to 2.7, preferably 0.8 to 2.5, More preferably, it is 1 to 2.3. If this partial pressure ratio is 0.6 or more, it is possible to prevent the yield of produced hydrocarbons from decreasing, and if this partial pressure ratio is 2.7 or less, the generated hydrocarbons are light. The tendency to increase minutes can be suppressed.

As another component that does not interfere with the FT reaction that may be mixed in the synthesis gas, carbon dioxide may be mentioned. In the method for producing hydrocarbons of the present invention, synthesis gas mixed with carbon dioxide obtained by a reforming reaction of natural gas or petroleum products can be used without any problem. Also, other components that do not interfere with the FT reaction other than carbon dioxide may be mixed. For example, methane or steam obtained from steam reforming reaction or autothermal reforming reaction of natural gas, petroleum products, etc. Or a synthesis gas containing partially oxidized nitrogen or the like may be used. The carbon dioxide can also be positively added to synthesis gas that does not contain carbon dioxide. In carrying out the method for producing hydrocarbons of the present invention, a synthesis gas containing carbon dioxide obtained by reforming natural gas or petroleum products by a self-thermal reforming method or a steam reforming method, If the FT reaction is used as it is without decarboxylation to remove carbon dioxide, the equipment construction cost and operation cost required for the decarboxylation treatment can be reduced, and the hydrocarbons obtained by the FT reaction can be produced. Cost can be reduced.

In the method for producing hydrocarbons of the present invention, the total pressure of the synthesis gas (mixed gas) to be subjected to the FT reaction (total value of partial pressures of all components) is preferably 0.5 to 10 MPa, and preferably 0.7 to 7 MPa. More preferred is 0.8 to 5 MPa. If this total pressure is 0.5 MPa or more, the chain growth probability is sufficient, and it is possible to prevent the yield of gasoline, kerosene, wax, and the like from decreasing. In terms of equilibrium, the higher the partial pressure of hydrogen and carbon monoxide, the more advantageous. However, if the total pressure is 10 MPa or less, the plant construction cost increases and the operation is increased by increasing the size of the compressor required for compression. The disadvantages from the industrial point of view, such as rising costs, can be suppressed accordingly.

In this FT reaction, generally, if the H ₂ / CO molar ratio of the synthesis gas is the same, the lower the reaction temperature, the higher the chain growth probability and C5 + selectivity, but the lower the CO conversion rate. Conversely, if the reaction temperature is increased, the chain growth probability and C5 + selectivity are lowered, but the CO conversion is increased. In addition, the higher the H ₂ / CO ratio, the higher the CO conversion rate, the lower the chain growth probability and C5 + selectivity, and vice versa when the H ₂ / CO ratio is low. The effect of these factors on the reaction varies depending on the type of catalyst used, etc., but in the method using the catalyst of the present invention, the reaction temperature is suitably 200 to 350 ° C., and 210 to 310 ° C. Preferably, 220 to 290 ° C is more preferable. The CO conversion rate is defined by the following formula.
[CO conversion rate]
CO conversion rate = [(number of CO moles in raw material gas per unit time) − (number of CO moles in outlet gas per unit time)] / number of CO moles in raw material gas per unit time × 100

Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

In the following examples, CO analysis was conducted by a thermal conductivity gas chromatograph (TCD-GC) using Active Carbon (60/80 mesh) as a separation column.
As the source gas, a synthesis gas (mixed gas of H ₂ and CO) added with 25 vol% of Ar as an internal standard was used.
Qualitative and quantitative analysis was performed by comparing the peak position and peak area of CO with Ar. The chemical component of the catalyst was identified by ICP (CQM-10000P, manufactured by Shimadzu Corporation).

Example 1
As an inorganic oxide carrier, spherical silica (Q-30: specific surface area 104 m ² / g, pore volume 1.2 cm ³ / g, pore diameter 33 nm) manufactured by Fuji Silysia Chemical was used. After sufficiently drying in advance, pure water (hereinafter abbreviated as “water”) was added dropwise to the silica to determine the saturated water absorption. The saturated water absorption at this time was 1.23 g / g-catalyst.
An aqueous solution obtained by dissolving 7.27 g of manganese nitrate hexahydrate (Mn Assay 19.14% by mass) in 13.0 g of water was impregnated in 7.35 g of silica, left for about 3 hours, and then in air at 110 ° C. for 2 hours. It dried and baked at 600 degreeC in the air for 3 hours in the muffle furnace.
Subsequently, the fired product obtained above was impregnated with an aqueous solution in which 2.46 g of cobalt nitrate (Co Assay 20.25% by mass) was dissolved in 13.0 g of water. This was dried in air at 110 ° C. and baked in a muffle furnace at 600 ° C. for 3 hours. Thereafter, the catalyst precursor supporting manganese and cobalt thus obtained was impregnated with an aqueous solution in which 0.368 g of ruthenium chloride (Ru Assay 40.79 mass%) was dissolved in 9.00 g of water, and left standing for 1 hour. The catalyst A was obtained by drying in air at 110 ° C. for 2 hours.

As a result of structural analysis of the catalyst A by X-ray diffraction, manganese was Mn ₂ O ₃ . As a result of analyzing the chemical composition of the catalyst A by ICP, ruthenium was 1.5% by mass in terms of metal, cobalt was 5.1% by mass in terms of metal, and Mn ₂ O ₃ was 20.2% by mass. It was.

2.4 g of catalyst A was charged into a reactor having an internal volume of 100 ml together with 40 ml (slurry concentration 5 mass%) of normal hexadecane (n-C ₁₆ H ₃₄ , hereinafter abbreviated as “solvent”) as a dispersion medium, Hydrogen was brought into contact with catalyst A at a pressure of 0.9 MPa · G, a temperature of 170 ° C., a flow rate of 100 (STP) ml / min (STP: standard temperature and pressure) and reduced for 3 hours.
After the reduction, the FT reaction was carried out at a temperature of 260 ° C. and a H ₂ + CO pressure of 0.9 MPa · G by switching to a synthesis gas having an H ₂ / CO ratio of about 2 (including about 25 vol. Ar). W / F (weight / flow) [g · hr / mol] was about 11 g · hr / mol. The CO conversion after 20 hours from the start of the FT reaction was about 73.5%, and the CO conversion after 100 hours was about 72.8%.

Example 2
Catalyst B was obtained in the same manner as in Example 1 except that the amount of cobalt nitrate was adjusted so that the cobalt content was 10% by mass.
As a result of chemical composition analysis of catalyst B by ICP, ruthenium was 1.5% by mass in terms of metal, cobalt was 10.2% by mass in terms of metal, and Mn ₂ O ₃ was 20.1% by mass. This catalyst B was subjected to the FT reaction in the same manner as in Example 1. The CO conversion after 20 hours from the start of the FT reaction was about 83.1%, and the CO conversion after 100 hours was about 82.9%.

Example 3
Catalyst C was obtained in the same manner as in Example 1 except that the amount of cobalt nitrate was adjusted so that the cobalt content was 20% by mass.
As a result of chemical composition analysis of catalyst C by ICP, ruthenium was 1.4% by mass in terms of metal, cobalt was 20.1% by mass in terms of metal, and Mn ₂ O ₃ was 20.2% by mass. This catalyst C was subjected to the FT reaction in the same manner as in Example 1. The CO conversion after 20 hours from the start of the FT reaction was about 90.4%, and the CO conversion after 100 hours was about 90.0%.

Example 4
Catalyst D was obtained in the same manner as in Example 1 except that the amount of ruthenium chloride was adjusted so that the content of ruthenium was 3% by mass.
As a result of analyzing the chemical composition of the catalyst D by ICP, ruthenium was 2.9% by mass in terms of metal, cobalt was 5.0% by mass in terms of metal, and Mn ₂ O ₃ was 20.1% by mass. This catalyst D was subjected to FT reaction in the same manner as in Example 1. The CO conversion after 20 hours from the start of the FT reaction was about 91.2%, and the CO conversion after 100 hours was about 91.0%.

Comparative Example 1
A catalyst E was obtained in the same manner as in Example 1 except that ruthenium was not contained and cobalt was adjusted to 10% by mass and manganese was adjusted to 20% by mass in terms of Mn ₂ O ₃ .
As a result of chemical composition analysis of catalyst E by ICP, cobalt was 10.1% by mass in terms of metal, and Mn ₂ O ₃ was 20.1% by mass.
As a result of subjecting this catalyst E to the FT reaction in the same manner as in Example 1, the reaction did not proceed at all. Therefore, the reduction treatment temperature with hydrogen was raised from 170 ° C. to 350 ° C. to carry out the FT reaction. The CO conversion after 20 hours from the start of the FT reaction was about 48.9%, and the CO conversion after 100 hours was about 41.1%.

Comparative Example 2
A catalyst F was obtained in the same manner as in Example 1 except that cobalt was not contained and that ruthenium was adjusted to 1.5% by mass and manganese was adjusted to 20% by mass in terms of Mn ₂ O ₃ .
As a result of analyzing the chemical composition of the catalyst F by ICP, ruthenium was 1.6% by mass in terms of metal, and Mn ₂ O ₃ was 20.0% by mass. This catalyst F was subjected to FT reaction in the same manner as in Example 1. The CO conversion after 20 hours from the start of the FT reaction was about 45.2%, and the CO conversion after 100 hours was about 37.7%.

Comparative Example 3
A catalyst G was obtained in the same manner as in Example 1 except that manganese was not contained and that ruthenium was adjusted to 1.5 mass% and cobalt was adjusted to 10 mass%.
As a result of analyzing the chemical composition of the catalyst G by ICP, ruthenium was 1.5% by mass in terms of metal, and cobalt was 10.2% by mass in terms of metal. This catalyst G was subjected to the FT reaction in the same manner as in Example 1. The CO conversion after 20 hours from the start of the FT reaction was about 51.3%, and the CO conversion after 100 hours was about 47.5%.

Comparative Example 4
Manganese and cobalt were not contained, and catalyst H was obtained in the same manner as in Example 1 except that ruthenium was adjusted to 1.5% by mass.
As a result of analyzing the chemical composition of the catalyst H by ICP, ruthenium was 1.6% by mass in terms of metal. This catalyst H was subjected to FT reaction in the same manner as in Example 1. The CO conversion after 20 hours from the start of the FT reaction was about 48.3%, and the CO conversion after 100 hours was about 20.5%.

Example 5
Alumina powder (γ-alumina, specific surface area 143 m ² / g, pore volume 0.6 cm ³ / g, pore diameter 16 nm) was used as the inorganic oxide carrier. 650 g of manganese nitrate hexahydrate (Mn Assay 19.14 mass%) was dissolved in 1330 g of water, 340 g of sufficiently dried alumina powder was mixed, and dispersed with a homogenizer (rotation speed: 4600 rpm) for about 20 minutes to prepare a slurry. This slurry was spray-dried with a spray dryer adjusted to an exhaust temperature of 170 ° C. The obtained powder was fired in air at 600 ° C. for 3 hours in a muffle furnace.
Subsequently, 8.85 g of the fired product obtained above was impregnated with an aqueous solution in which 4.92 g of cobalt nitrate (Co Assay 20.25 mass%) was dissolved in 6.00 g of water. This was dried in air at 110 ° C. and baked in a muffle furnace at 600 ° C. for 3 hours. Thereafter, the catalyst precursor containing manganese and cobalt thus obtained was impregnated with an aqueous solution in which 0.368 g of ruthenium chloride (Ru Assay 40.79 mass%) was dissolved in 4.50 g of water, and left for 1 hour. The catalyst I was obtained by drying at 110 ° C. for 2 hours in air.
As a result of structural analysis of the catalyst I by X-ray diffraction, manganese was Mn ₂ O ₃ . As a result of chemical composition analysis of catalyst I by ICP, ruthenium was 1.5% by mass in terms of metal, cobalt was 10.1% by mass in terms of metal, and Mn ₂ O ₃ was 30.2% by mass. It was.
This catalyst I was subjected to the FT reaction in the same manner as in Example 1. The CO conversion after 20 hours from the start of the FT reaction was about 58.6%, and the CO conversion after 100 hours was about 58.0%.

Comparative Example 5
A catalyst J was obtained in the same manner as in Example 5 except that ruthenium was not contained and cobalt was adjusted to 10% by mass.
As a result of chemical composition analysis of catalyst J by ICP, cobalt was 10.0% by mass in terms of metal, and Mn ₂ O ₃ was 30.3% by mass.
As a result of subjecting this catalyst J to the FT reaction in the same manner as in Example 1, the reaction did not proceed at all. Therefore, the reduction treatment temperature with hydrogen was raised from 170 ° C. to 350 ° C. to carry out the FT reaction. The CO conversion rate 20 hours after the start of the FT reaction was about 1.3%, and the CO conversion did not proceed before reaching 100 hours.

Comparative Example 6
A catalyst K was obtained in the same manner as in Example 5 except that cobalt was not contained and ruthenium was adjusted to 1.5% by mass.
As a result of analyzing the chemical composition of the catalyst K by ICP, ruthenium was 1.5% by mass in terms of metal, and Mn ₂ O ₃ was 30.2% by mass. This catalyst K was subjected to the FT reaction in the same manner as in Example 1. The CO conversion after 20 hours from the start of the FT reaction was about 29.0%, and the CO conversion after 100 hours was about 23.1%.

Tables 1 to 3 show the experimental results of Examples 1 to 5 and Comparative Examples 1 to 6. From these tables, the CO conversion of the catalyst in which manganese, cobalt, and ruthenium coexist is greatly improved compared to a catalyst containing these components alone or only two kinds, and stable for a long time. It is clear that it has an excellent performance such as exhibiting a high activity.

Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. This application is based on a Japanese patent application filed on Jun. 17, 2008 (Japanese Patent Application No. 2008-158312) and a Japanese patent application filed on March 6, 2009 (Japanese Patent Application No. 2009-053741). Is incorporated herein by reference.

The catalyst of the present invention in which manganese, cobalt and ruthenium coexist can significantly improve the CO conversion rate compared to a catalyst containing these components alone or in any one of two types. The productivity of hydrogen is high and the activity is high, so that the catalyst cost and the reactor size can be expected to be reduced.
The detailed mechanism of catalytic activity improvement by coexistence of manganese, cobalt, and ruthenium has not been clarified, but the activity improvement that cannot be explained by the simple additivity of ruthenium and cobalt, which are active metal species, for the FT reaction Is observed, and manganese which does not show activity in the FT reaction is also an essential component, so it is presumed that it is due to the combined effect of these components.

Claims

Inorganic oxide support, manganese as catalyst standard, 10-50% by mass in terms of Mn 2 O 3 , ruthenium as catalyst standard, 0.5-5% by mass in terms of metal, cobalt as catalyst standard, 5-30 in terms of metal A catalyst for Fischer-Tropsch synthesis, characterized by containing a mass%.
The Fischer-Tropsch synthesis catalyst according to claim 1, wherein the inorganic oxide support is silica or alumina.
The catalyst for Fischer-Tropsch synthesis according to claim 1 or 2, wherein the inorganic oxide support has a spherical shape.
Manganese is contained in the inorganic oxide support so that the content is 10 to 50% by mass in terms of catalyst, converted to Mn 2 O 3 , and cobalt is 5 to 30% by mass in terms of catalyst, based on catalyst. And dried, and then calcined at 300 to 700 ° C. to prepare a catalyst precursor. In the catalyst precursor, ruthenium is contained on a catalyst basis and converted to metal in an amount of 0.5 to 5 mass. %, And then dried at a temperature of 200 ° C. or less, a method for producing a Fischer-Tropsch synthesis catalyst.
A method for producing hydrocarbons, characterized in that a gas mainly composed of hydrogen and carbon monoxide is brought into contact with the catalyst according to any one of claims 1 to 3.