JPWO2020027321A1 - Light hydrocarbon synthesis catalyst structure, light hydrocarbon production equipment and method for producing light hydrocarbons - Google Patents

Abstract

The light hydrocarbon synthesis catalyst structure (1) according to the present invention comprises a carrier (10) having a porous structure composed of a zeolite-type compound, and at least one metal fine particle (20) contained in the carrier (10). To be equipped. The carrier (10) has a passage (11) communicating with the outside of the carrier (10), the average inner diameter in a part of the passage (11) is 0.95 nm or less, and the metal fine particles (20) have an average inner diameter. Is present in the passage (11) of 0.95 nm or less.

Description

The present invention relates to a light hydrocarbon synthesis catalyst structure, a light hydrocarbon production apparatus, and a method for producing a light liquid hydrocarbon, and in particular, a light hydrocarbon capable of selectively synthesizing a light hydrocarbon from carbon monoxide and hydrogen. The present invention relates to a synthetic catalyst structure, a light hydrocarbon production apparatus, and a method for producing a light liquid hydrocarbon.

_{Carbon monoxide gas (CO) and hydrogen gas (H 2} ) are the main components as a method for producing hydrocarbon compounds used as raw materials for liquid or solid fuel products such as synthetic oil and synthetic fuel, which are alternative fuels for petroleum. A Fischer-Tropsch synthesis reaction (hereinafter, also referred to as “FT synthesis reaction”) is known in which a hydrocarbon, particularly a liquid or solid hydrocarbon, is synthesized from a synthetic gas to be used. As a catalyst used in this FT synthesis reaction, for example, Patent Document 1 discloses a catalyst in which an active metal such as cobalt or iron is supported on a carrier such as silica or alumina, and Patent Document 2 discloses cobalt. , Zyla or titanium, and a catalyst containing silica are disclosed.

The catalyst used in the FT synthesis reaction is, for example, a catalyst in which a carrier such as silica or alumina is impregnated with a cobalt salt, a ruthenium salt or the like and then calcined to support a cobalt oxide and / or a ruthenium oxide (a catalyst in which a cobalt oxide and / or a ruthenium oxide is supported. It can be obtained as an unreduced catalyst). In order for the catalyst thus obtained to exhibit sufficient activity for the FT synthesis reaction, as disclosed in Patent Document 3, the catalyst is brought into contact with a reducing gas such as hydrogen gas for reduction treatment. However, it is necessary to convert the active metals cobalt and / or ruthenium from the oxide state to the metal state.

By the way, in a reactor that carries out an FT synthesis reaction, a heavy hydrocarbon having a relatively large number of carbon atoms is mainly synthesized as a liquid component, and a light hydrocarbon having a relatively small number of carbon atoms is mainly synthesized as a gas component. However, since hydrocarbons having various carbon atoms are synthesized in the FT synthesis reaction, it is necessary to carry out an extra process such as a decomposition process and a purification process after the synthesis process in order to obtain a desired hydrocarbon. Therefore, it is desirable to be able to control the carbon number distribution of the product as much as possible in the FT synthesis reaction.

In Patent Document 4, a core-shell type catalyst consisting of a core portion forming an FT synthesis catalyst and a shell portion for decomposing and reducing the weight of hydrocarbons is used, and hydrocarbons are grown with the FT synthesis catalyst in the core portion. , A technique for reducing the weight of the produced hydrocarbon by decomposing the product obtained by the FT synthesis reaction with a catalyst for decomposing the hydrocarbon in the shell portion is disclosed. However, Patent Document 4 only discloses the carbon number distribution mainly for hydrocarbons having 5 or more carbon atoms. In addition, since the carbon number of the hydrocarbon synthesized by the cobalt catalyst in the core part is adjusted by the reaction on the zeolite surface in the shell part, even after the softening of the product is prepared in the shell part, the core part or the adjacent shell It may react again with the part. Therefore, it is difficult to control the selectivity of hydrocarbons having a specific range of carbon numbers, and in particular, it is difficult to control the carbon number distribution for light hydrocarbons having a smaller number of carbon numbers.

On the other hand, light hydrocarbons such as propylene and butene produced as gas components in the FT synthesis reaction are known to be used as basic raw materials for various chemical products. Although such light hydrocarbons can be produced in the FT synthesis reaction, their selectivity is still low. That is, in the product obtained by the FT synthesis reaction, a technique for enhancing the selectivity of light hydrocarbons over heavy hydrocarbons has not yet been established. In addition, by developing such a technology, not only the selectivity of light hydrocarbons will be improved, but also the additional operations such as the purification process required in the conventional synthesis process will be omitted, and the production efficiency will be improved. Is also desired.

Japanese Unexamined Patent Publication No. 4-227847 Japanese Unexamined Patent Publication No. 59-12440 International Publication No. 2015/072573 International Publication No. 2014/1422282

An object of the present invention is a light hydrocarbon synthesis catalyst structure capable of enhancing the selectivity of a light hydrocarbon in the synthesis of a hydrocarbon, a method for producing a light hydrocarbon using the catalyst structure, and the catalyst structure. It is an object of the present invention to provide a light hydrocarbon production apparatus having the above.

As a result of intensive studies to achieve the above object, the present inventors have provided a carrier having a porous structure composed of a zeolite-type compound and at least one metal fine particle contained in the carrier. The carrier has a passage communicating with the outside of the carrier, the average inner diameter in a part of the passage is 0.95 nm or less, and the metal fine particles are present in the passage having the average inner diameter of 0.95 nm or less. It has been found that the selectivity of light hydrocarbons can be enhanced in the synthesis of hydrocarbons, particularly in the FT synthesis reaction, by using the catalyst structure.

That is, the gist structure of the present invention is as follows.
[1] A carrier having a porous structure composed of a zeolite-type compound and
With at least one metal fine particle contained in the carrier,
The carrier has a passage that communicates with the outside of the carrier.
The average inner diameter of a part of the passage is 0.95 nm or less, and the average inner diameter is 0.95 nm or less.
A light hydrocarbon synthesis catalyst structure characterized in that the metal fine particles are present in a passage having an average inner diameter of 0.95 nm or less.
[2] The light hydrocarbon synthesis catalyst structure according to the above [1], wherein the average inner diameter in a part of the passage is 0.75 nm or less.
[3] The light hydrocarbon synthesis catalyst structure according to the above [1] or [2], wherein the average inner diameter in a part of the passage is 0.55 nm or more and less than 0.75.
[4] The light hydrocarbon synthesis catalyst structure according to the above [1] or [2], wherein the average inner diameter in a part of the passage is 0.63 nm or more and less than 0.75.
[5] The light hydrocarbon synthesis catalyst structure according to the above [1] or [2], wherein the average inner diameter in a part of the passage is larger than 0.39 nm and less than 0.68 nm.
[6] The passage includes any one of the one-dimensional pores, the two-dimensional pores, and the three-dimensional pores defined by the skeleton structure of the zeolite-type compound, and the one-dimensional pores, the two-dimensional pores, and the three-dimensional pores. The light zeolite synthesis according to any one of the above [1] to [5], which has a diameter-expanded portion different from any of the above, and the metal fine particles are present at least in the diameter-expanded portion. Catalyst structure.
[7] The light hydrocarbon according to the above [6], wherein the enlarged diameter portion communicates with a plurality of holes constituting any one of the one-dimensional hole, the two-dimensional hole, and the three-dimensional hole. Hydrogen synthesis catalyst structure.
[8] The light hydrocarbon synthesis catalyst according to the above [6] or [7], wherein the average particle size of the metal fine particles is larger than the average inner diameter of the entire passage and equal to or less than the inner diameter of the enlarged diameter portion. Structure.
[9] One of the above [1] to [8], wherein the metal element (M) of the metal fine particles is contained in an amount of 0.5% by mass or more with respect to the light hydrocarbon synthesis catalyst structure. The light hydrocarbon synthesis catalyst structure according to the above.
[10] The amount of the metal-containing aqueous solution charged as the raw material of the metal fine particles is the silicon (A) constituting the precursor material (A) which is the raw material of the carrier with respect to the metal element (M) contained in the metal-containing aqueous solution. The light hydrocarbon synthesis catalyst structure according to any one of the above [1] to [9], which is 10 or more and 1000 or less in terms of the ratio of Si) (atomic number ratio Si / M).
[11] The light hydrocarbon synthesis catalyst structure according to any one of [1] to [10] above, wherein the metal fine particles contain Co, Fe, Ni, Ru or an alloy containing at least one of them. body.
[12] A light hydrocarbon production apparatus having the light hydrocarbon synthesis catalyst structure according to any one of the above [1] to [11].
[13] The light hydrocarbon production apparatus according to the above [12], comprising a light hydrocarbon synthesis catalyst structure in which the range of the average inner diameter in a part of the passage differs depending on the number of carbon atoms of the light hydrocarbon to be synthesized.
[14] A method for producing a light hydrocarbon, which synthesizes a light hydrocarbon from carbon monoxide and hydrogen by using the light hydrocarbon synthesis catalyst structure according to any one of the above [1] to [11].
[15] The method for producing a light hydrocarbon according to the above [14], which uses a light hydrocarbon synthesis catalyst structure in which the range of the average inner diameter in a part of the passage differs depending on the number of carbon atoms of the light hydrocarbon to be synthesized. ..

According to the present invention, a light hydrocarbon synthesis catalyst structure capable of enhancing the selectivity of a light hydrocarbon in the synthesis of a hydrocarbon, particularly in an FT synthesis reaction, and a method for producing a light hydrocarbon using the catalyst structure. , And a light hydrocarbon production apparatus having the catalyst structure. Further, for example, by utilizing such a catalyst structure for the FT synthesis reaction, it is possible to omit additional operations such as a purification process required in the conventional synthesis process, and as a result, the production efficiency can be improved. Can be done.

FIG. 1 is a schematic view showing the internal structure of the light hydrocarbon synthesis catalyst structure according to the embodiment of the present invention so that the internal structure can be understood, and FIG. 1 (a) is a perspective view (partially in cross section). (Show), FIG. 1 (b) is a partially enlarged cross-sectional view. 2A and 2B are partially enlarged cross-sectional views for explaining an example of the function of the light hydrocarbon synthesis catalyst structure of FIG. 1, FIG. 2A is a sieve function, and FIG. 2B is a catalytic ability. It is a figure. FIG. 3 is a flowchart showing an example of a method for producing the light hydrocarbon synthesis catalyst structure of FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[Structure of light hydrocarbon synthesis catalyst structure]
FIG. 1 is a diagram schematically showing a configuration of a light hydrocarbon synthesis catalyst structure (hereinafter, also simply referred to as “catalyst structure”) according to an embodiment of the present invention, and FIG. 1A is a perspective view (1). (Parts are shown in cross section), (b) is a partially enlarged cross-sectional view. The catalyst structure in FIG. 1 shows an example thereof, and the shape, dimensions, etc. of each configuration according to the present invention are not limited to those in FIG.

As shown in FIG. 1A, the catalyst structure 1 includes a carrier 10 having a porous structure composed of a zeolite-type compound, and at least one metal fine particle 20 contained in the carrier 10.

In the catalyst structure 1, the plurality of metal fine particles 20, 20, ... Are included in the porous structure of the carrier 10. The metal fine particles 20 are catalytic substances having catalytic ability (catalytic activity). The details of the metal fine particles will be described later. Further, the metal fine particles 20 may be particles containing a metal oxide, a metal alloy, or a composite material thereof.

The carrier 10 has a porous structure, and as shown in FIG. 1 (b), preferably, a plurality of holes 11a, 11a, ... Are formed so that a passage 11 communicating with the outside of the carrier 10 is formed. Have. Here, the average inner diameter of a part of the passage 11 of the carrier 10 is 0.95 nm or less, and the metal fine particles 20 are present in the passage 11 having an average inner diameter of 0.95 nm or less, and the average inner diameter is preferably 0. It is held in the passage 11 having a diameter of 95 nm or less.

With such a configuration, the selectivity of light hydrocarbons can be enhanced in the synthesis of hydrocarbons, particularly in the FT synthesis reaction. Further, the movement of the metal fine particles 20 in the carrier 10 is restricted, and the agglomeration of the metal fine particles 20 and 20 is effectively prevented. As a result, the decrease in the effective surface area of the metal fine particles 20 can be effectively suppressed, and the catalytic activity of the metal fine particles 20 can be maintained for a long period of time. As a result, the catalyst structure 1 can suppress a decrease in catalytic activity due to aggregation of the metal fine particles 20, and can extend the life of the catalyst structure 1. Further, by extending the life of the catalyst structure 1, the frequency of replacement of the catalyst structure 1 can be reduced, the amount of waste of the used catalyst structure 1 can be significantly reduced, and resources can be saved. ..

Normally, when the catalyst structure 1 is used in a fluid (for example, synthetic gas), there is a possibility of receiving an external force from the fluid. When the metal fine particles 20 are only held on the outer surface of the carrier 10 in an attached state, there is a problem that the metal fine particles 20 are easily separated from the outer surface of the carrier 10 due to the influence of an external force from the fluid. On the other hand, in the catalyst structure 1, since the metal fine particles 20 are present in at least the passage 11 of the carrier 10, the metal fine particles 20 are difficult to separate from the carrier 10 even if they are affected by an external force due to the fluid. That is, when the catalyst structure 1 is in the fluid, the fluid flows into the passage 11 from the hole 11a of the carrier 10, so that the speed of the fluid flowing in the passage 11 depends on the flow path resistance (friction force). It is considered that the speed of the fluid flowing on the outer surface of the carrier 10 is slower than that of the fluid. Due to the influence of such flow path resistance, the pressure received from the fluid by the metal fine particles 20 held in the passage 11 is lower than the pressure received by the metal fine particles 20 from the fluid outside the carrier 10. Therefore, the detachment of the metal fine particles 20 contained in the carrier 10 can be effectively suppressed, and the catalytic activity of the metal fine particles 20 can be stably maintained for a long period of time. It is considered that the flow path resistance as described above becomes larger as the passage 11 of the carrier 10 has a plurality of bends and branches and the inside of the carrier 10 has a more complicated and three-dimensional three-dimensional structure. ..

Further, the passage 11 includes any one of the one-dimensional pores, the two-dimensional pores and the three-dimensional pores defined by the skeleton structure of the zeolite-type compound, and the one-dimensional pores, the two-dimensional pores and the three-dimensional pores. It is preferable to have a diameter-expanded portion 12 different from each other, and at this time, the metal fine particles 20 are preferably present at least in the diameter-expanded portion 12, and are included in at least the diameter-expanded portion 12. Is more preferable. Further, it is preferable that the enlarged diameter portion 12 communicates with a plurality of holes 11a, 11a constituting any one of the one-dimensional hole, the two-dimensional hole, and the three-dimensional hole. As a result, a separate passage different from the one-dimensional hole, the two-dimensional hole, or the three-dimensional hole is provided inside the carrier 10, so that the function of the metal fine particles 20 can be further exerted. The one-dimensional hole referred to here is a tunnel-type or cage-type hole forming a one-dimensional channel, or a plurality of tunnel-type or cage-type holes (plurality of holes) forming a plurality of one-dimensional channels. One-dimensional channel). A two-dimensional hole refers to a two-dimensional channel in which a plurality of one-dimensional channels are two-dimensionally connected, and a three-dimensional hole refers to a three-dimensional channel in which a plurality of one-dimensional channels are three-dimensionally connected. Point to. As a result, the movement of the metal fine particles 20 in the carrier 10 is further restricted, and the separation of the metal fine particles 20 and the aggregation of the metal fine particles 20 and 20 can be more effectively prevented. The inclusion refers to a state in which the metal fine particles 20 are included in the carrier 10. At this time, the metal fine particles 20 and the carrier 10 do not necessarily have to be in direct contact with each other, and another substance (for example, a surfactant or the like) is interposed between the metal fine particles 20 and the carrier 10. Therefore, the metal fine particles 20 may be indirectly held by the carrier 10.

FIG. 1B shows a case where the metal fine particles 20 are included in the enlarged diameter portion 12, but the present invention is not limited to this configuration, and a part of the metal fine particles 20 is the enlarged diameter portion 12. It may be held in the passage 11 in a state of protruding to the outside. Further, the metal fine particles 20 may be partially embedded in a portion of the passage 11 other than the enlarged diameter portion 12 (for example, an inner wall portion of the passage 11), or may be held by sticking or the like.

Further, the passage 11 is three-dimensionally formed inside the carrier 10 including a branching portion or a merging portion, and the diameter expanding portion 12 is preferably provided at the branching portion or the merging portion of the passage 11. ..

_{The overall average inner diameter DT} of the passage 11 formed in the carrier 10 is calculated from the average values of the minor and major diameters of the holes 11a constituting any of the one-dimensional hole, the two-dimensional hole, and the three-dimensional hole. For example, it is 0.10 nm or more and 1.50 nm or less, preferably 0.38 nm or more and 0.95 nm or less. When light hydrocarbons are synthesized by the FT synthesis reaction, carbon monoxide and hydrogen are the raw materials in the FT synthesis reaction, and the molecular size of carbon monoxide is about 0.38 nm and the molecular size of hydrogen is about 0.29 nm. Is. Therefore, the average inner diameter _DT of the entire passage 11 is preferably 0.40 nm or more and 1.50 nm or less, more preferably 0.49 nm or more and 0.95 nm or less, and 0.49 nm or more and 0.70 nm or less. Is more preferable. _{The inner diameter DE} of the enlarged diameter portion 12 is, for example, 0.5 nm or more and 50 nm or less, preferably 1.1 nm or more and 40 nm or less, and more preferably 1.1 nm or more and 3.3 nm or less. The inner diameter D _E of the enlarged diameter section 12 depends on for example the pore size of which will be described later precursor material (A), and the average particle diameter D _C of the fine metal particles 20 to be inclusion. _{The inner diameter DE} of the enlarged diameter portion 12 has a size capable of including the metal fine particles 20.

The carrier 10 is composed of a zeolite-type compound. Examples of the zeolite-type compound include silicate compounds such as zeolite (aluminosilicate), cation-exchanged zeolite, and silicalite, zeolite-related compounds such as aluminoborate, aluminohydrate, and germaniumate, and molybdenum phosphate. Phosphate-based zeolite-like substances and the like. Above all, the zeolite-type compound is preferably a silicate compound.

The skeleton structure of the zeolite type compound is FAU type (Y type or X type), MTW type, MFI type, FER type (ferrierite), LTA type (A type), MWW type (MCM-22), MOR type (mordenite). ), LTL type (L type), BEA type (beta type), CHA type and the like. Among these, MFI type, MOR type, BEA type and CHA type are preferable, and MFI type, MOR type and BEA type are more preferable from the viewpoint of the pore size capable of sufficient molecular diffusion of the product whose selectivity is to be improved. preferable.

The zeolite compound has a plurality of pores having pore diameters corresponding to each skeleton structure. For example, in the hole diameter of the MFI type ([010] axis), the short hole diameter is 0.53 nm (5.30 Å) and the long hole diameter is 0.56 nm (5.60 Å), so that the average hole diameter (average inner diameter). Is about 0.55 nm (5.50 Å). Further, in the hole diameter of CHA type ([001] axis), the short hole diameter is 0.38 nm (3.8 Å), and the long hole diameter is 0.38 (without short side and long side) nm (3.8 Å). Therefore, the average pore diameter (average inner diameter) is about 0.38 nm (3.8 Å). On the other hand, when the inner diameter of the passage 11 existing inside the carrier 10 depending on the skeleton structure of the zeolite-type compound is smaller than the size of the obtained product, for example, the molecular size (chain length size), the passage 11 is used. The movement of such products is restricted. Further, in the synthesis of hydrocarbons, a carbon chain grows by contacting a reactant with a catalyst existing in the pores of a zeolite-type compound. Therefore, a carrier 10 composed of a zeolite-type compound having _{an average inner diameter DF} of 0.95 nm or less in a part of the passage 11, that is, a passage in which the metal fine particles 20 as a catalyst substance are contained is used. As a result, the growth of carbon chains is suppressed based on the pore size formed in the zeolite-type compound, and the production of heavy hydrocarbons having a relatively large molecular size is suppressed. _{By controlling the average inner diameter DF} of the passage 11 in which the metal fine particles 20 are present to 0.95 nm or less in this way, in the synthesis of hydrocarbons, for example, the Fischer-Tropsch synthesis reaction, a heavy substance having 7 or more carbon atoms. It is possible to increase the selectivity of light hydrocarbons having 6 or less carbon atoms while suppressing the formation of hydrocarbons. Although the average inner diameter _DF differs depending on the skeleton structure of the zeolite-type compound, the lower limit of the _{average inner diameter DF} is set from the viewpoint that products having 2 or more carbon atoms are useful as raw materials for various synthetic substances. is preferably not less than 0.38 nm, from the viewpoint 3 or more products carbon atoms are useful as petrochemical raw material, the lower limit of the average inner diameter D _F is more preferably greater than 0.39 nm. Further, the pores existing in the zeolite compound are not necessarily circular but may be polygonal. Therefore, the average inner diameter _DF may be calculated from, for example, a value obtained by adding a long pore diameter (major axis) and a short pore diameter (minor axis) and equally dividing each pore.

By controlling the average inner diameter _DF more strictly, the selectivity of the produced light hydrocarbon can be further enhanced, and in particular, the chain length size (length in the major axis direction of the molecule) equivalent to the _{average inner diameter DF.} It is possible to increase the selectivity of light hydrocarbons having. For example, the chain length size of a trait hydrocarbon having 2 carbon atoms (length in the major axis direction of the molecule) is 0.36 nm or more and less than 0.43 nm, and the chain length size of a light hydrocarbon having 3 carbon atoms (molecule length). Axial length) is 0.49 nm or more and less than 0.59 nm, chain length size (longitudinal length of molecule) of a light hydrocarbon having 4 carbon atoms is 0.50 nm or more and less than 0.70 nm, carbon number The chain length size of the light hydrocarbon with 5 (length in the major axis direction of the molecule) is 0.50 nm or more and less than 0.79 nm, and the chain length size of the light hydrocarbon with 6 carbon atoms (length in the major axis direction of the molecule). Is 0.59 nm or more and less than 0.95 nm. The chain length size of n-hexene having 6 carbon atoms (length in the major axis direction of the molecule) is about 0.91 nm, and the chain length size of n-penten having 5 carbon atoms (length in the major axis direction of the molecule). The chain length size (length in the major axis direction of the molecule) of n-butene having 4 carbon atoms is about 0.78 nm, and the chain length of propylene having 3 carbon atoms is about 0.65 nm. The major size (length in the major axis direction of the molecule) is about 0.52 nm, and the chain length size of ethylene having two carbon atoms (length in the major axis direction of the molecule) is about 0.39 nm. Therefore, when increasing the selectivity of a hydrocarbon having 4 or less carbon atoms as a product, particularly an olefin, the average inner diameter _DF in a part of the passage 11 is preferably 0.75 nm or less, and the hydrocarbon having 4 carbon atoms is carbonized. When increasing the selectivity of hydrogen, for example butene (n-butene and isobutene), the average inner diameter _DF in a part of the passage 11 is more preferably less than 0.75 nm, more preferably 0.55 nm or more and less than 0.75 nm. Is even more preferable. In particular, the average in a part of the passage 11 from the viewpoint that the selectivity of the hydrocarbon having 4 carbon atoms is higher than that of the hydrocarbon having 3 carbon atoms and the recovery of butene (n-butene and isobutene) can be performed more selectively. It is particularly preferable that the inner diameter _DF is 0.63 nm or more and less than 0.75 nm. When increasing the selectivity of a hydrocarbon having 3 carbon atoms as a product, for example, propylene, the average inner diameter _DF in a part of the passage 11 is preferably less than 0.68 nm, more than 0.39 nm and less than 0.68 nm. Is more preferable. Further, when increasing the selectivity of a hydrocarbon having 2 carbon atoms as a product, for example, ethylene, the average inner diameter _DF in a part of the passage 11 is preferably 0.38 nm or more and less than 0.55 nm. Further, the selectivity of the light hydrocarbon may be influenced not only by the pore size formed in the zeolite-type compound, but also by the skeleton structure of the zeolite-type compound, the molecular motion of the produced light hydrocarbon, and the like. For example, when the skeleton structure of a zeolite-type compound is MFI-type, the selectivity of olefins such as propylene and butene (n-butene and isobutene) tends to increase. As described above, even a light hydrocarbon having a chain length size (length in the major axis direction of the molecule) larger than _{the average inner diameter DF can be enhanced in selectivity by these influences.}

Metal fine particles 20, and if the primary particle, there are the cases are secondary particles in which primary particles are formed by aggregation, the average particle diameter D _C of the fine metal particles 20 are preferably the overall average of the passage 11 larger than the inner diameter _{D T,} is and less than or equal to the inner diameter _{D E} of the enlarged diameter portion _{12 (D T <D C ≦} D E). Such metal fine particles 20 are preferably present in the enlarged diameter portion 12 in the passage 11, and the movement of the metal fine particles 20 in the carrier 10 is restricted. Therefore, even when the metal fine particles 20 receive an external force from the fluid, the movement of the metal fine particles 20 in the carrier 10 is suppressed, and the enlarged diameter portions 12, 12, ... It is possible to effectively prevent the metal fine particles 20, 20, ... Existing in each of the above from coming into contact with each other.

The average particle diameter D _C of the fine metal particles 20, in either case of the primary particles and secondary particles, preferably 0.08nm or more. The ratio _(D C / _{D T)} of the average particle diameter _{D C} of the fine metal particles 20 to the total of the average inner diameter _{D T} of the passage 11 is preferably 0.05 to 300, more preferably 0.1 or more It is 30 or less, more preferably 1.1 or more and 30 or less, and particularly preferably 1.4 or more and 3.6 or less. Further, the metal element (M) of the metal fine particles 20 is preferably contained in an amount of 0.5% by mass or more with respect to the catalyst structure 1 and 0.5% by mass or more with respect to the catalyst structure 1. It is more preferably contained in an amount of 5% by mass or less, and further preferably contained in an amount of 1.5% by mass or less. For example, when the metal element (M) is Co, the content (mass%) of the Co element is represented by {(mass of Co element) / (mass of all elements of catalyst structure 1)} × 100. ..

The metal fine particles may be composed of an unoxidized metal, for example, may be composed of a single metal, or may be composed of a mixture of two or more kinds of metals. The "metal" (as a material) constituting the metal fine particles includes a single metal containing one kind of metal element (M) and a metal alloy containing two or more kinds of metal elements (M), and is one kind. It means a general term for metals containing the above metal elements.

Examples of such metals include platinum (Pt), palladium (Pd), ruthenium (Ru), nickel (Ni), cobalt (Co), molybdenum (Mo), tungsten (W), iron (Fe), and chromium ( Cr), cerium (Ce), copper (Cu), magnesium (Mg), aluminum (Al) and the like can be mentioned, and it is preferable that one or more of the above is the main component. Among these metals, from the viewpoint of usefulness in the FT synthesis reaction, the metal fine particles preferably contain Co, Fe, Ni, Ru or an alloy containing at least one of them, and from the viewpoint of improving selectivity. , Co, Fe, Ru or an alloy containing at least one of them is more preferable, and from the viewpoint of production cost, it is further preferable to contain Co, Fe or an alloy containing at least one of them.

Further, the ratio of silicon (Si) constituting the carrier 10 (atomic number ratio Si / M) to the metal element (M) constituting the metal fine particles 20 is preferably 10 or more and 1000 or less, preferably 50 or more and 200 or less. Is more preferable, and 100 or more and 200 or less is further preferable. If the above ratio is larger than 1000, the activity of the metal fine particles as a catalytic substance may not be sufficiently obtained, such as low activity. On the other hand, if the ratio is smaller than 10, the ratio of the metal fine particles 20 tends to be too large, and the strength of the carrier 10 tends to decrease. The metal fine particles 20 referred to here refer to fine particles held or carried inside the carrier 10, and do not include metal fine particles adhering to the outer surface of the carrier 10. Further, the content of the metal fine particles 20 in the catalyst structure 1 may be calculated from the metal-containing aqueous solution and the precursor material (A) used in the method for producing the catalyst structure 1 described later. In this case, the amount of the metal-containing aqueous solution charged as the raw material of the metal fine particles 20 is silicon (Si) constituting the precursor material (A) which is the raw material of the carrier 10 with respect to the metal element (M) contained in the metal-containing aqueous solution. ) (Atomic number ratio Si / M), it is preferably 10 or more and 1000 or less, more preferably 50 or more and 200 or less, and further preferably 100 or more and 200 or less.

[Function of light hydrocarbon synthesis catalyst structure]
As described above, the catalyst structure 1 includes a carrier 10 having a porous structure and at least one metal fine particle 20 contained in the carrier. The catalyst structure 1 exhibits the catalytic ability of the metal fine particles 20 when the metal fine particles 20 contained in the carrier come into contact with the fluid. Specifically, the fluid in contact with the outer surface 10a of the catalyst structure 1 flows into the carrier 10 through the holes 11a formed in the outer surface 10a, is guided into the passage 11, and moves through the passage 11. Then, it goes out to the outside of the catalyst structure 1 through the other holes 11a. In the path through which the fluid moves through the passage 11, the contact with the metal fine particles 20 existing in the passage having an average inner diameter of 0.95 nm or less in the passage 11 causes a catalytic reaction by the metal fine particles 20. Further, the catalyst structure 1 has molecular sieving ability because the carrier has a porous structure.

First, the molecular sieving ability of the catalyst structure 1 will be described with reference to FIG. 2 (a). As shown in FIG. 2A, the molecule 15a having a size equal to or smaller than the pore diameter of the hole 11a, in other words, equal to or smaller than the inner diameter of the passage 11, can penetrate into the carrier 10. On the other hand, the molecule 15b having a size exceeding the pore diameter of the pore 11a cannot penetrate into the carrier 10. As described above, when the fluid contains a plurality of types of compounds, the reaction of the compound that cannot penetrate into the carrier 10 is restricted, and the compound that can penetrate into the carrier 10 can be reacted.

Among the compounds produced in the carrier 10 by the reaction, a compound composed of molecules having a size equal to or smaller than the pore size of the pores 11a can be discharged to the outside of the carrier 10 through the pores 11a, and is obtained as a reaction product. On the other hand, a compound that cannot go out of the carrier 10 from the pore 11a can be taken out of the carrier 10 if it is converted into a compound composed of molecules having a size that can go out of the carrier 10. .. Further, due to the molecular motion of the produced compound, a molecule larger than the pore size of the pore 11a can also move out of the carrier 10 while expanding and contracting the molecule. As described above, by using the catalyst structure 1 in which the pore diameter of the pores 11a, particularly the pore diameter in which the metal fine particles are present, is controlled, a specific reaction product can be selectively obtained.

In the catalyst structure 1, as shown in FIG. 2B, the metal fine particles 20 are included in the enlarged diameter portion 12 of the passage 11. The average particle diameter _{D C} of the fine metal particles is greater than the average internal diameter _{D F} at the part of the passage 11, and if smaller than the inner diameter _{D E} of the enlarged diameter portion _{12 (D F <D C <} D E), a metal A small passage 13 is formed between the fine particles and the enlarged diameter portion 12. Therefore, as shown by the arrow in FIG. 2B, the fluid that has entered the small passage 13 comes into contact with the metal fine particles. Since each metal fine particle is included in the enlarged diameter portion 12, movement within the carrier 10 is restricted. This prevents agglomeration of the metal fine particles in the carrier 10. As a result, a large contact area between the metal fine particles and the fluid can be stably maintained.

Specifically, when the molecule that has entered the passage 11 comes into contact with the metal fine particles 20, the molecule (substance to be modified) is modified by a catalytic reaction. _{In the present invention, by using the catalyst structure 1 in which the average inner diameter DF} in a part of the passage 11 is controlled, for example, a light hydrocarbon (CH) is made from a mixed gas containing hydrogen and carbon monoxide as main components. _{(Excluding 4} ), preferably light hydrocarbons of C6 or less, particularly light hydrocarbons gaseous at room temperature (hydrocarbons of C3 to C4) can be selectively produced. Further, this FT synthesis reaction containing hydrogen and carbon monoxide as main components is carried out at a high temperature of, for example, 180 ° C. to 350 ° C., but since the metal fine particles 20 are contained in the carrier 10, they are affected by heating. Hard to receive. In particular, since the metal fine particles 20 are present in the enlarged diameter portion 12, the movement of the metal fine particles 20 in the carrier 10 is further restricted, and aggregation (sintering) between the metal fine particles 20 is further suppressed. As a result, the decrease in catalytic activity is further suppressed, and the life of the catalyst structure 1 can be further extended. Further, by using the catalyst structure 1 for a long period of time, even if the catalytic activity is lowered, the metal fine particles 20 are not bound to the carrier 10, so that the activation treatment (reduction treatment) of the metal fine particles 20 can be easily performed. be able to.

[Manufacturing method of light hydrocarbon synthesis catalyst structure]
FIG. 3 is a flowchart showing a method for manufacturing the catalyst structure 1 of FIG.

(Step S1: Preparation step)
As shown in FIG. 3, first, a precursor material (A) for obtaining a carrier having a porous structure composed of a zeolite-type compound is prepared. The precursor material (A) is preferably a regular mesopore material, and can be appropriately selected depending on the type (composition) of the zeolite-type compound constituting the carrier of the catalyst structure.

Here, when the zeolite-type compound constituting the carrier of the catalyst structure is a silicate compound, in the regular mesopore material, the pores having a pore diameter of 1 nm or more and 50 nm or less are one-dimensional, two-dimensional or three-dimensional. It is preferably a compound consisting of a Si—O skeleton that is dimensionally uniform in size and regularly developed. Such regular mesopore materials can be obtained as various compounds depending on the synthetic conditions, and specific examples of the compounds include, for example, SBA-1, SBA-15, SBA-16, KIT-6, FSM-. 16, MCM-41 and the like can be mentioned, and MCM-41 is particularly preferable. The pore diameter of SBA-1 is 10 nm or more and 30 nm or less, the pore diameter of SBA-15 is 6 nm or more and 10 nm or less, the pore diameter of SBA-16 is 6 nm, the pore diameter of KIT-6 is 9 nm, and the pore diameter of FSM-16. Is 3 nm or more and 5 nm or less, and the pore diameter of MCM-41 is 1 nm or more and 10 nm or less. Moreover, examples of such a regular mesoporous material include mesoporous silica, mesoporous aluminosilicate, mesoporous metallosilicate and the like.

The precursor material (A) may be either a commercially available product or a synthetic product. When the precursor material (A) is synthesized, it can be carried out by a known method for synthesizing a regular mesopore material. For example, a mixed solution containing a raw material containing the constituent elements of the precursor material (A) and a template agent for defining the structure of the precursor material (A) is prepared, and the pH is adjusted as necessary. , Hydrothermal synthesis. Then, the precipitate (product) obtained by hydrothermal treatment is recovered (for example, filtered), washed and dried as necessary, and further calcined to obtain a powdery regular mesopore material. The precursor material (A) is obtained. Here, as the solvent of the mixed solution, for example, water, an organic solvent such as alcohol, or a mixed solvent thereof or the like can be used. The raw material is selected according to the type of carrier, and examples thereof include silica agents such as tetraethoxysilane (TEOS), fumed silica, and quartz sand. Further, as the template agent, various surfactants, block copolymers and the like can be used, and it is preferable to select the template agent according to the type of the compound of the regular mesopore substance. For example, when MCM-41 is produced. A surfactant such as hexadecyltrimethylammonium bromide is suitable for this. The hydrothermal treatment can be performed, for example, in a closed container at 80 to 800 ° C. for 5 hours to 240 hours under the treatment conditions of 0 to 2000 kPa. The firing treatment can be performed in air, for example, at 350 to 850 ° C. for 2 to 30 hours.

(Step S2: Impregnation step)
Next, the prepared precursor material (A) is impregnated with a metal-containing solution to obtain a precursor material (B).

The metal-containing solution may be a solution containing a metal component (for example, metal ion) corresponding to the metal element (M) constituting the metal fine particles of the catalyst structure. For example, the metal element (M) may be used as a solvent. It can be prepared by dissolving the contained metal salt. Examples of such metal salts include metal salts such as chlorides, hydroxides, oxides, sulfates and nitrates, and nitrates are particularly preferable. As the solvent, for example, water, an organic solvent such as alcohol, or a mixed solvent thereof or the like can be used.

The method of impregnating the precursor material (A) with the metal-containing solution is not particularly limited. For example, before the firing step described later, the precursor material (A) is stirred while stirring the precursor material (A). ), It is preferable to add the metal-containing solution in small portions in a plurality of times. Further, from the viewpoint that the metal-containing solution can more easily penetrate into the pores of the precursor material (A), a surfactant is added as an additive to the precursor material (A) in advance before adding the metal-containing solution. It is preferable to add it. Such an additive has a function of coating the outer surface of the precursor material (A), suppresses the metal-containing solution added thereafter from adhering to the outer surface of the precursor material (A), and forms a metal. It is considered that the contained solution is more likely to penetrate into the pores of the precursor material (A).

Examples of such additives include nonionic surfactants such as polyoxyethylene oleyl ether, polyoxyethylene alkyl ether, and polyoxyethylene alkyl phenyl ether. Since these surfactants have a large molecular size and cannot penetrate into the pores of the precursor material (A), they do not adhere to the inside of the pores, and the metal-containing solution does not penetrate into the pores. It is considered not to interfere. As a method of adding the nonionic surfactant, for example, 50% by mass or more and 500% by mass or less of the nonionic surfactant is added to the precursor material (A) before the firing step described later. Is preferable. If the amount of the nonionic surfactant added to the precursor material (A) is less than 50% by mass, the above-mentioned inhibitory action is unlikely to be exhibited, and 500 nonionic surfactants are added to the precursor material (A). Adding more than% by mass is not preferable because the viscosity increases too much. Therefore, the amount of the nonionic surfactant added to the precursor material (A) is set to a value within the above range.

The amount of the metal-containing solution added to the precursor material (A) is the amount of the metal element (M) contained in the metal-containing solution impregnated in the precursor material (A) (that is, the precursor material (B). ), It is preferable to make appropriate adjustments in consideration of the amount of the metal element (M) contained therein. For example, before the firing step described later, the amount of the metal-containing solution added to the precursor material (A) is adjusted to the metal element (M) contained in the metal-containing solution added to the precursor material (A). It is preferable to adjust the ratio (atomic number ratio Si / M) of silicon (Si) constituting the precursor material (A) so that it is 10 or more and 1000 or less, and it is 50 or more and 200 or less. It is more preferable to adjust it, and it is further preferable to adjust it so that it is 100 or more and 200 or less. For example, when a surfactant is added to the precursor material (A) as an additive before the metal-containing solution is added to the precursor material (A), the metal-containing solution to be added to the precursor material (A) is added. By setting the amount to 50 or more and 200 or less in terms of the atomic number ratio Si / M, the metal element (M) of the metal fine particles can be contained in an amount of 0.5% by mass or more with respect to the catalyst structure. For example, it can be contained in the range of 0.5% by mass or more and 2.5% by mass or less. In the state of the precursor material (B), the amount of the metal element (M) existing inside the pores is the same under various conditions such as the metal concentration of the metal-containing solution, the presence or absence of the above additives, and other conditions such as temperature and pressure. If there is, it is roughly proportional to the amount of the metal-containing solution added to the precursor material (A). Further, the amount of the metal element (M) contained in the precursor material (B) is proportional to the amount of the metal element constituting the metal fine particles contained in the carrier of the catalyst structure. Therefore, by controlling the amount of the metal-containing solution added to the precursor material (A) within the above range, the metal-containing solution can be sufficiently impregnated inside the pores of the precursor material (A), and thus the metal-containing solution can be sufficiently impregnated. , The amount of metal fine particles contained in the carrier of the catalyst structure can be adjusted.

After impregnating the precursor material (A) with the metal-containing solution, a cleaning treatment may be performed, if necessary. As the cleaning solution, water, an organic solvent such as alcohol, or a mixed solution thereof can be used. Further, it is preferable that the precursor material (A) is impregnated with a metal-containing solution, washed if necessary, and then further dried. Examples of the drying treatment include natural drying for about one night and high-temperature drying at 150 ° C. or lower. If a large amount of water contained in the metal-containing solution or water in the washing solution remains in the precursor material (A) and the firing treatment described later is performed, the regular mesopores of the precursor material (A) are formed. It is preferable to dry it sufficiently because the skeletal structure as a substance may be damaged.

(Step S3: Baking step)
Next, the precursor material (B) in which the precursor material (A) for obtaining a carrier having a porous structure composed of a zeolite-type compound is impregnated with a metal-containing solution is calcined to obtain the precursor material (C). To get.

The firing treatment is preferably carried out in air, for example, at 350 to 850 ° C. for 2 to 30 hours. By such a firing treatment, the metal component impregnated in the pores of the regular mesopore material grows into crystals, and metal fine particles are formed in the pores.

(Step S4: Hydrothermal treatment step)
Next, a mixed solution in which the precursor material (C) and the structure defining agent are mixed is prepared, and the precursor material (C) obtained by firing the precursor material (B) is hydrothermally treated to have a catalyst structure. Get the body.

The structure defining agent is a template agent for defining the skeletal structure of the carrier of the catalyst structure, and for example, a surfactant can be used. The structure defining agent is preferably selected according to the skeletal structure of the carrier of the catalyst structure, for example, tetramethylammonium bromide (TMABr), tetraethylammonium bromide (TEABr), tetrapropylammonium bromide (TPABr), tetraethylammonium hydroxide. A surfactant such as (TEAOH) is suitable.

The mixture of the precursor material (C) and the structure defining agent may be performed during the main hydrothermal treatment step or before the hydrothermal treatment step. The method for preparing the mixed solution is not particularly limited, and the precursor material (C), the structure-defining agent, and the solvent may be mixed at the same time, or the precursor material (C) and the structure-defining solvent may be mixed. After each of the agents is dispersed in individual solutions, the respective dispersion solutions may be mixed. As the solvent, for example, water, an organic solvent such as alcohol, or a mixed solvent thereof or the like can be used. Further, it is preferable to adjust the pH of the mixed solution with an acid or a base before performing hydrothermal treatment.

The hydrothermal treatment can be carried out by a known method, and for example, it is preferably carried out in a closed container at 80 to 800 ° C. for 5 hours to 240 hours under treatment conditions of 0 to 2000 kPa. Further, the hydrothermal treatment is preferably performed in a basic atmosphere. Although the reaction mechanism here is not always clear, the skeletal structure of the precursor material (C) as a regular mesopore material gradually collapses by performing hydrothermal treatment using the precursor material (C) as a raw material. A new skeletal structure (porous structure) as a carrier of the catalyst structure is formed by the action of the structure-defining agent while the positions of the metal fine particles in the pores of the precursor material (C) are generally maintained. .. The catalyst structure thus obtained comprises a carrier having a porous structure and metal fine particles contained therein, and the carrier has a passage in which a plurality of pores communicate with each other due to the porous structure, and the metal fine particles are formed. At least part of it is present in the passage of the carrier. Further, in the present embodiment, in the hydrothermal treatment step, a mixed solution in which the precursor material (C) and the structure defining agent are mixed is prepared, and the precursor material (C) is hydrothermally treated. Not limited to this, the precursor material (C) may be hydrothermally treated without mixing the precursor material (C) and the structure defining agent.

The precipitate (catalyst structure) obtained after the hydrothermal treatment is preferably recovered (for example, filtered) and then washed, dried and calcined as necessary. As the cleaning solution, water, an organic solvent such as alcohol, or a mixed solution thereof can be used. Examples of the drying treatment include natural drying for about one night and high-temperature drying at 150 ° C. or lower. If the firing treatment is performed with a large amount of water remaining in the precipitate, the skeletal structure as a carrier of the catalyst structure may be destroyed, so that it is preferably sufficiently dried. Further, the firing treatment can be performed in air, for example, at 350 to 850 ° C. for 2 to 30 hours. By such a firing treatment, the structure defining agent adhering to the catalyst structure is burned down. Further, the catalyst structure can be used as it is without calcining the recovered precipitate, depending on the purpose of use. For example, when the environment in which the catalyst structure is used is a high-temperature environment with an oxidizing atmosphere, the structure-defining agent is burned out by exposing it to the use environment for a certain period of time, and the catalyst structure similar to that in the case of firing treatment is produced. Since it is obtained, it can be used as it is.

The production method described above is an example in which the metal element (M) contained in the metal-containing solution impregnated in the precursor material (A) is a metal species (for example, a noble metal) that is difficult to oxidize.

When the metal element (M) contained in the metal-containing solution impregnated in the precursor material (A) is a metal species (for example, Fe, Co, Cu, etc.) that is easily oxidized, after the hydrothermal treatment step, It is preferable that the precursor material (C) that has been hydrothermally treated is subjected to a reduction treatment. When the metal element (M) contained in the metal-containing solution is a metal species that is easily oxidized, the metal component is oxidized by the heat treatment in the steps (steps S3 to S4) after the impregnation treatment (step S2). .. Therefore, the metal oxide fine particles are inherent in the carrier formed in the hydrothermal treatment step (step S4). Therefore, in order to obtain a catalyst structure in which metal fine particles are contained in the carrier, it is desirable that after the above hydrothermal treatment, the recovered precipitate is calcined and further reduced in a reducing gas atmosphere such as hydrogen gas. By performing the reduction treatment, the metal oxide fine particles contained in the carrier are reduced, and the metal fine particles corresponding to the metal element (M) constituting the metal oxide fine particles are formed. As a result, a catalyst structure in which metal fine particles are contained in the carrier is obtained. It should be noted that such a reduction treatment may be performed as needed. For example, when the environment in which the catalyst structure is used is a reducing atmosphere, the metal oxide fine particles can be removed by exposing the catalyst structure to the use environment for a certain period of time. Since it is reduced, a catalyst structure similar to that in the case of reduction treatment can be obtained, so that it can be used as it is in a state where oxide fine particles are contained in the carrier.

The present invention provides a method for producing a light hydrocarbon, which synthesizes a light hydrocarbon from carbon monoxide and hydrogen using a catalyst. Such a catalyst includes a carrier 10 having a porous structure composed of a zeolite-type compound, and at least one metal fine particle 20 contained in the carrier 10, and the carrier 10 has a passage 11 communicating with the outside of the carrier. However, the average inner diameter of a part of the passage 11 is 0.95 nm or less, and the metal fine particles 20 include the catalyst structure 1 existing in the passage 11 having an average inner diameter of 0.95 nm or less. That is, the present invention provides a method for producing a light hydrocarbon that synthesizes a light hydrocarbon from carbon monoxide and hydrogen by using the above-mentioned light hydrocarbon synthesis catalyst structure.

For example, the raw material for producing a light hydrocarbon using the FT synthesis reaction is not particularly limited as long as it is a synthetic gas containing molecular hydrogen and carbon monoxide as main components, but hydrogen / carbon monoxide. A synthetic gas having a molar ratio of 1.5 to 2.5 is preferable, and a synthetic gas having a molar ratio of 1.8 to 2.2 is more preferable. Further, the reaction conditions of the FT synthesis reaction are not particularly limited, and can be carried out under known conditions. For example, the reaction temperature is preferably 200 to 500 ° C. and 200 to 350 ° C., and the pressure (absolute pressure) is preferably 0.1 to 3.0 MPa.

The FT synthesis reaction can be carried out in a process known as a reaction process for Fischer-Tropsch synthesis, for example, a fixed bed, a supercritical fixed bed, a slurry bed, a fluidized bed or the like. Preferred processes include fixed beds, supercritical fixed beds and slurry beds.

In the present invention, a light hydrocarbon production apparatus having the above catalyst structure may be provided. Such a light hydrocarbon production apparatus is not particularly limited as long as it can synthesize a light hydrocarbon using the catalyst structure, and is, for example, a commonly used production of a reactor, a reaction column, or the like. The device can be used. By using the catalyst structure according to the present invention in such a light hydrocarbon production apparatus, the production apparatus can also exhibit the same effect as described above.

Further, when synthesizing a light hydrocarbon from carbon monoxide and hydrogen in a method for producing a light hydrocarbon using the above catalyst structure and a light hydrocarbon production apparatus having the above catalyst structure, the light hydrocarbon to be synthesized It is preferable to use a catalyst structure in which the range _{of the average inner diameter DF} in a part of the passage 11 differs depending on the number of carbon atoms. As a result, the selectivity of the produced light hydrocarbon can be further enhanced, and in particular, the selectivity of the light hydrocarbon having the same size as the _{average inner diameter DF can be enhanced.} When there are a plurality of desired light hydrocarbons, a plurality of reaction columns are prepared in advance, and each reaction column is provided with a catalyst structure having a different _{average inner diameter DF range according to the target light hydrocarbon.} You may use it. Further, the catalyst structure already used in the reaction column _{may be replaced with another catalyst structure having a different average inner diameter DF} range, or the reaction column provided with the catalyst structure may be replaced with an average inner diameter _DF. It may be replaced with a reaction column having another catalyst structure having a different range of.

The catalyst structure according to the embodiment of the present invention, the method for producing the same, the method for producing a hydrocarbon using the catalyst structure, and the hydrocarbon production apparatus having the catalyst structure have been described above. It is not limited to the embodiment, and various modifications and modifications can be made based on the technical idea of the present invention.

(Examples 1 to 24)
[Synthesis of precursor material (A)]
A mixed aqueous solution prepared by mixing a silica agent (tetraethoxysilane (TEOS), manufactured by Wako Pure Chemical Industries, Ltd.) and a surfactant as a template agent is prepared, the pH is adjusted as appropriate, and the temperature is 80 to 350 ° C. in a closed container. Was hydrothermally treated for 100 hours. Then, the produced precipitate was filtered off, washed with water and ethanol, and further calcined in air at 600 ° C. for 24 hours to obtain a precursor material (A) of the type and pore size shown in Table 1. .. As the surfactant, hexadecyltrimethylammonium bromide (CTAB) (manufactured by Wako Pure Chemical Industries, Ltd.) was used.

[Preparation of precursor materials (B) and (C)]
Next, a metal-containing aqueous solution was prepared by dissolving a metal salt containing the metal element (M) in water according to the metal element (M) constituting the types of metal fine particles shown in Table 1. As the metal salt, the following were used according to the type of the metal fine particles (“metal fine particles: metal salt”).
・ Co: Cobalt nitrate (II) hexahydrate (manufactured by Wako Pure Chemical Industries, Ltd.)
-Ni: Nickel nitrate (II) hexahydrate (manufactured by Wako Pure Chemical Industries, Ltd.)
-Fe: Iron (III) Nitrate Nine Hydrate (manufactured by Wako Pure Chemical Industries, Ltd.)
-Ru: Ruthenium (III) chloride anhydride (manufactured by Tokyo Chemical Industry Co., Ltd.)

Next, the metal-containing aqueous solution is added little by little to the powdery precursor material (A) in a plurality of times, dried at room temperature (20 ° C. ± 10 ° C.) for 12 hours or more, and the precursor material (B) is dried. Got

Further, the condition of presence / absence of the additive shown in Table 1 is set to "Yes", and the polyoxyethylene (15) oleyl ether (NIKKOL) as an additive is compared with the precursor material (A) before the addition of the metal-containing aqueous solution. A pretreatment for adding an aqueous solution of BO-15V (manufactured by Nikko Chemicals Co., Ltd.) was performed, and then a metal-containing aqueous solution was added as described above.

The amount of the metal-containing aqueous solution added to the precursor material (A) (charged amount) is the silicon (Si) constituting the precursor material (A) with respect to the metal element (M) contained in the metal-containing aqueous solution. ) Was converted to the ratio (atomic number ratio Si / M), and the value was adjusted to be the value shown in Table 1.

Next, the precursor material (B) impregnated with the metal-containing aqueous solution obtained as described above was calcined in air at 600 ° C. for 24 hours to obtain a precursor material (C).

The precursor material (C) obtained as described above and the structure-defining agent shown in Table 1 are mixed to prepare a mixed aqueous solution, and in a closed container, 80 to 350 ° C., the pH shown in Table 1 and Hydrothermal treatment was performed under the condition of time. Then, the produced precipitate was filtered off, washed with water, dried at 100 ° C. for 12 hours or more, and further calcined in air at 600 ° C. for 24 hours. Then, the fired product was recovered and reduced at 500 ° C. for 60 minutes under the inflow of hydrogen gas to obtain a catalyst structure having the carrier shown in Table 1 and metal fine particles as a catalyst substance (Example). 1 to 24).

(Comparative Example 1)
In Comparative Example 1, cobalt oxide powder (II, III) (manufactured by Sigma-Aldrich Japan LLC) having an average particle size of 50 nm or less was mixed with MFI type silica light, and hydrogen reduction treatment was performed in the same manner as in Example to carry out a carrier. A catalyst structure was obtained in which highly active cobalt fine particles were adhered as a catalyst substance on the outer surface of the silica light. The MFI type silica light was synthesized by the same method as in Example 1 except for the step of adding a metal.

[evaluation]
Various characteristics of the catalyst structure of the above example and the silica light of the comparative example were evaluated under the conditions shown below.

[A] Cross-section observation For the catalyst structure of the above example and the silica light of the comparative example, an observation sample was prepared by a pulverization method, and a cross-section observation was performed using a transmission electron microscope (TEM) (TITAN G2, manufactured by FEI). Was done. As a result, it was confirmed that in the catalyst structure of the above-mentioned example, the catalyst substance is contained and retained inside the carrier made of silicalite or zeolite. On the other hand, in the silica light of Comparative Example 1, the catalytic substance was only attached to the outer surface of the carrier and was not present inside the carrier.

Further, in the above-mentioned examples, for the catalyst structure in which the metal is iron fine particles (Fe), a cross section is cut out by FIB (focused ion beam) processing, and SEM (SU8020, manufactured by Hitachi High Technologies America), EDX (X-Max). , Horiba Seisakusho) was used for cross-sectional elemental analysis. As a result, Fe element was detected from the inside of the carrier. From the results of cross-sectional observation by the above TEM and SEM / EDX, it was confirmed that iron fine particles were present inside the carrier.

[B] Average inner diameter of the passage of the carrier and the average particle diameter of the catalyst substance In the TEM image taken by the cross-sectional observation performed in the above evaluation [A], 500 carriers were arbitrarily selected, and the major axis and the major axis of each were selected. The minor axis was measured, each inner diameter was calculated from the average value (N = 500), and the average value of the inner diameter was obtained and used as the average inner diameter _DT of the entire passage of the carrier. Similarly, for the catalyst substance, 500 catalyst substances are arbitrarily selected from the above TEM image, the particle size of each is measured (N = 500), the average value is obtained, and the average of the catalyst substances is obtained. I was having a particle diameter _{D C.} The results are shown in Table 1. The average inner diameter _DF is determined in each pore of each zeolite structure based on the literature values described in the zeolite structure database (http://www.iza-structure.org/databases/). It was calculated from the value obtained by adding the major axis and the minor axis and dividing them equally.

In addition, in order to confirm the average particle size and the dispersed state of the catalytic substance, analysis was performed using SAXS (Small Angle X-ray Scattering). The measurement by SAXS was performed using the beamline BL19B2 of Spring-8. The obtained SAXS data was fitted with a spherical model by the Guinier approximation method, and the particle size was calculated. The particle size was measured for the catalyst structure in which the metal is iron fine particles. Further, as a comparison target, commercially available iron fine particles (manufactured by Wako) were observed and measured by SEM.

As a result, iron fine particles of various sizes are randomly present in the range of about 50 nm to 400 nm in the commercially available product, whereas iron having an average particle size of 1.2 nm to 2.0 nm obtained from the TEM image is randomly present. In the catalyst structure of each example using fine particles, a scattering peak having a particle size of 10 nm or less was also detected in the measurement result of SAXS. From the measurement result of SAXS and the measurement result of the cross section by SEM / EDX, it was found that the catalyst substance having a particle size of 10 nm or less was present in the carrier in a dispersed state having a uniform particle size and a very high particle size.

[C] Relationship between the amount of the metal-containing solution added and the amount of metal encapsulated inside the carrier The amount of the atomic number ratio Si / M = 100, 200 (M = Co, Fe, Ru, Ni) is the amount of the catalyst substance added. To prepare a catalyst structure in which metal fine particles were encapsulated inside the carrier. Then, the amount of metal (mass%) encapsulated inside the carrier of each catalyst structure produced with the above addition amount was measured. Further, the catalyst structure having an atomic number ratio of Si / M = 100, 200, 1000 is added to the metal-containing solution in the same manner as the catalyst structure having an atomic number ratio of Si / M = 100, 200 in Examples 1 to 24. The amount was adjusted and separately prepared, and the amount of metal (mass%) encapsulated inside the carrier of each catalyst structure was measured. Further, the catalyst structure having an atomic number ratio of Si / M = 50 is separately used in the same manner as the catalyst structure having an atomic number ratio of Si / M = 100, 200, except that the amount of the metal-containing solution added is different. The amount of metal (% by mass) encapsulated inside the carrier of the catalyst structure was measured.

The amount of metal was quantified either by ICP (radio frequency inductively coupled plasma) alone or in combination with ICP and XRF (X-ray fluorescence analysis). The XRF (energy dispersion type fluorescent X-ray analyzer "SEA1200VX", manufactured by SSI Nanotechnology Co., Ltd.) was performed under the conditions of a vacuum atmosphere and an acceleration voltage of 15 kV (using a Cr filter) or an acceleration voltage of 50 kV (using a Pb filter). XRF is a method of calculating the abundance of metal by fluorescence intensity, and a quantitative value (converted to mass%) cannot be calculated by XRF alone. Therefore, the amount of metal in the catalyst structure to which metal was added at Si / M = 100 was quantified by ICP analysis, and the amount of metal in the catalyst structure to which metal was added at Si / M = 50 and less than 100 was measured by XRF. Was calculated based on the ICP measurement result.

As a result, it was confirmed that the amount of metal encapsulated in the catalyst structure increased as the amount of the metal-containing solution added increased, at least in the range of the atomic number ratio Si / M of 50 or more and 1000 or less. Was done.

[D] Performance Evaluation The catalytic ability of the catalytic substance was evaluated for the catalyst structure of the above example and the silica light of the comparative example. The results are shown in Table 1.

<Selectivity of light hydrocarbons>
First, 70 mg of the catalyst structure is filled in a normal pressure flow reactor, hydrogen (8 ml / min) and carbon monoxide (4 ml / min) are supplied, and the catalyst structure is heated at 250 ° C. and normal pressure (0.1 MPa). However, Fischer-Tropsch synthesis was performed for 1 hour. A single microreactor (Rx-3050SR, manufactured by Frontier Lab) was used as the normal pressure flow reactor.

After completion of the reaction, the recovered product gas and product liquid were subjected to component analysis by gas chromatography-mass spectrometry (GC / MS). As the analyzer for the produced gas, TRACE 1310GC (manufactured by Thermo Fisher Scientific Co., Ltd., detector: thermal conductivity detector) was used.

As a result of the analysis, among the reaction products, a C3 compound group containing a hydrocarbon having 3 carbon atoms (hereinafter, also simply referred to as “C3”) or a C4 compound group containing a hydrocarbon having 4 carbon atoms (hereinafter, simply referred to as “C3”). When the selectivity of "C4") is 20% or more, it is judged that the selectivity of the light hydrocarbon is excellent, and "◎", the selectivity of C3 or C4 is 10% or more, 20%. If it is less than, it is judged that the selectivity of the light hydrocarbon is good, and if the selectivity of C3 or C4 is 5% or more and less than 10%, the selectivity of the light hydrocarbon is When it is judged that the pass level is (possible) and the selectivity of C3 or C4 is less than 5%, it is judged that the selectivity of the light hydrocarbon is inferior (impossible) and it is marked as "x". .. Examples of the compound contained in the C3 compound group include propane, propylene, propanol and the like, and examples of the compound contained in the C4 compound group include n-butane, n-butene, isobutane, isobutane, n-butanol, isobutanol and the like. Can be mentioned.

Further, when the selectivity of propylene or butene (n-butene and isobutene) is 10% or more, it is judged that the selectivity of the light hydrocarbon is excellent, and "◎", propylene or butene (n-butene and isobutene). When the selectivity of (isobutene) is 5% or more and less than 10%, it is judged that the selectivity of the light hydrocarbon is good, and the selectivity of "○", propylene or butene (n-butene and isobene) is When it is 3% or more and less than 5%, it is judged that the selectivity of the light hydrocarbon is the acceptable level (possible), and the selectivity of "Δ", propylene or butene (n-butene and isobutene) is 3%. When it was less than, it was judged that the selectivity of the light hydrocarbon was inferior (impossible), and it was evaluated as "x".

The selectivity of C3 or C4 was calculated from the following formula (1).
{C3 (mol) or C4 (mol) produced / total product (mol)} x 100 ... (1)

The selectivity of propylene or butene (n-butene and isobutene) was calculated by the following formula (2).
{Propylene (mol) produced or butene (n-butene and isobutene) (mol) / total product (mol)} x 100 ... (2)

For Comparative Example 1, the same performance evaluation as above was performed.

In addition, the selectivity of light hydrocarbons is mainly related to _{the pore size (average inner diameter DF} ) depending on the skeletal structure of the zeolite-type compound. Therefore, in Examples 1 to 24, the selectivity of the light hydrocarbon could be improved by selecting the zeolite having an appropriate skeletal structure according to the desired molecular size of the light hydrocarbon.

Further, in Examples 1, 2, 7, 8, 13, 14, 19, and 20, a carrier having a skeleton structure of MFI type zeolite is used. Therefore, the selectivity of propylene and butene (n-butene and isobutene) as olefins tends to be improved. In particular, MFI-type zeolite, the average inner diameter _{D F} of [010] axis is 0.55 nm, the average inner diameter _{D F} of [100] axis is 0.53 nm, the average inner diameter _{D F} of each axis of n- butenes Despite being smaller than the molecular size, it showed good or excellent selectivity for butene (n-butene and isobutene).

Furthermore, the catalytic activity of Co, Fe and Ru is higher than that of Ni. Therefore, Examples 1 to 18 in which Co, Fe or Ru are used as the metal fine particles are superior in performance of selectivity of light hydrocarbons to Examples 19 to 24 in which Ni is used as the metal fine particles. ..

From the above results, the catalyst structure (Examples 1 to 24) shows excellent selectivity of light hydrocarbons in the synthesis of hydrocarbons, particularly in the FT synthesis reaction of synthesizing light hydrocarbons from carbon monoxide and hydrogen. It turned out. Further, by utilizing such a catalyst structure for the FT synthesis reaction, it is possible to omit additional operations such as a purification process required in the conventional synthesis process, and as a result, the production efficiency can be improved. ..

1 light hydrocarbon synthesis catalyst structure 10 support 10a outer surface 11 passages 11a hole 12 enlarged diameter portion 13 Small passage 20 metal fine particles D _C average particle diameter D _F average inner diameter D _E inner diameter

Claims (15)

A carrier having a porous structure composed of a zeolite-type compound,
With at least one metal fine particle contained in the carrier,
The carrier has a passage that communicates with the outside of the carrier.
The average inner diameter of a part of the passage is 0.95 nm or less, and the average inner diameter is 0.95 nm or less.
A light hydrocarbon synthesis catalyst structure characterized in that the metal fine particles are present in a passage having an average inner diameter of 0.95 nm or less. The light hydrocarbon synthesis catalyst structure according to claim 1, wherein the average inner diameter in a part of the passage is 0.75 nm or less. The light hydrocarbon synthesis catalyst structure according to claim 1 or 2, wherein the average inner diameter in a part of the passage is 0.55 nm or more and less than 0.75 nm. The light hydrocarbon synthesis catalyst structure according to claim 1 or 2, wherein the average inner diameter in a part of the passage is 0.63 nm or more and less than 0.75 nm. The light hydrocarbon synthesis catalyst structure according to claim 1 or 2, wherein the average inner diameter in a part of the passage is larger than 0.39 nm and less than 0.68 nm. The passage is any one of the one-dimensional pores, the two-dimensional pores and the three-dimensional pores defined by the skeleton structure of the zeolite-type compound, and any of the one-dimensional pores, the two-dimensional pores and the three-dimensional pores. The light hydrocarbon synthesis catalyst structure according to any one of claims 1 to 5, which has a different diameter-expanded portion and the metal fine particles are present in at least the enlarged-diameter portion. The light hydrocarbon synthesis catalyst structure according to claim 6, wherein the enlarged diameter portion communicates a plurality of holes constituting any one of the one-dimensional hole, the two-dimensional hole, and the three-dimensional hole. body. The light hydrocarbon synthesis catalyst structure according to claim 6 or 7, wherein the average particle size of the metal fine particles is larger than the average inner diameter of the entire passage and equal to or less than the inner diameter of the enlarged diameter portion. The light hydrocarbon synthesis according to any one of claims 1 to 8, wherein the metal element (M) of the metal fine particles is contained in an amount of 0.5% by mass or more based on the light hydrocarbon synthesis catalyst structure. Catalyst structure. The amount of the metal-containing aqueous solution charged as the raw material of the metal fine particles is the amount of silicon (Si) constituting the precursor material (A) which is the raw material of the carrier with respect to the metal element (M) contained in the metal-containing aqueous solution. The light hydrocarbon synthesis catalyst structure according to any one of claims 1 to 9, which is 10 or more and 1000 or less in terms of ratio (atomic number ratio Si / M). The light hydrocarbon synthesis catalyst structure according to any one of claims 1 to 10, wherein the metal fine particles contain Co, Fe, Ni, Ru or an alloy containing at least one of them. A light hydrocarbon production apparatus having the light hydrocarbon synthesis catalyst structure according to any one of claims 1 to 11. The light hydrocarbon production apparatus according to claim 12, further comprising a light hydrocarbon synthesis catalyst structure in which the range of the average inner diameter in a part of the passage differs depending on the number of carbon atoms of the light hydrocarbon to be synthesized. A method for producing a light hydrocarbon, which synthesizes a light hydrocarbon from carbon monoxide and hydrogen by using the light hydrocarbon synthesis catalyst structure according to any one of claims 1 to 11. The method for producing a light hydrocarbon according to claim 14, wherein a light hydrocarbon synthesis catalyst structure in which the range of the average inner diameter in a part of the passage differs depending on the number of carbon atoms of the light hydrocarbon to be synthesized is used.

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