Composite catalyst

Abstract

This composite catalyst comprises: a solid oxide catalyst provided with a stabilized zirconia support and an active metal supported on the stabilized zirconia support; and a zeolite. The stabilized zirconia support has a tetragonal and / or cubic crystal structure in which a stabilizing element forms a solid solution with zirconia, and the active metal includes Fe and an alkali metal. The zeolite includes at least a zeolite that has one skeleton structure selected from the group consisting of MFI structure, MOR structure, CHA structure, FER structure, AEI structure, BEA structure, and FAU structure.

Description

Composite catalyst

[0001] The present invention relates to a composite catalyst.

[0002] Conventionally, a catalyst for reacting carbon dioxide and hydrogen to obtain methane has been known. As such a catalyst, for example, a catalyst for methanation reaction in which Ni is supported on a stabilized zirconia support has been proposed (see, for example, Patent Document 1).

[0003] International Publication No. 2016 / 013488

[0004] However, although the methanation reaction catalyst of Patent Document 1 can produce methane from carbon dioxide at a high conversion rate, it is difficult to produce hydrocarbons having a larger number of carbon atoms.

[0005] An object of the present invention is to provide a composite catalyst capable of improving the synthesis ratio of hydrocarbons having 3 to 20 carbon atoms and suppressing an excessive increase in the olefin-to-paraffin ratio in the hydrocarbons.

[0006] The present invention [1] is a composite catalyst containing a solid oxide catalyst and zeolite, wherein the solid oxide catalyst includes a stabilized zirconia support and an active metal supported on the stabilized zirconia support, the stabilized zirconia support has a stabilized element dissolved in zirconia and has a tetragonal and / or cubic crystal structure, the active metal includes Fe and an alkali metal, and the zeolite includes at least a zeolite having one framework structure selected from the group consisting of MFI structure, MOR structure, CHA structure, FER structure, AEI structure, BEA structure, and FAU structure.

[0007] The present invention [2] includes the composite catalyst according to the above [1], wherein the active metal consists of Fe and K.

[0008] The present invention [3] includes the composite catalyst according to the above [1], wherein the active metal consists of Fe, Co, and K.

[0009] The present invention [4] includes a composite catalyst according to any one of the above [1] to [3], wherein the stabilizing element is at least one element selected from the group consisting of Y, Sm, Ca, Ce, La, Pr, Nd, Gd, Dy, and Mg.

[0010] The present invention [5] includes the composite catalyst described in [4] above, wherein the stabilizing element is Y.

[0011] The present invention [6] includes a composite catalyst according to any one of the above [1] to [5], wherein, in atomic percent based on the elemental state of the metal, the atomic ratio of the total Fe and the alkali metal to the sum of Zr constituting the stabilized zirconia support and the stabilizing element and the active metal (= (Fe + alkali metal) / (Zr + stabilizing element + active metal) × 100) is 55 atomic percent or more and 95 atomic percent or less.

[0012] The present invention [7] includes a composite catalyst according to any one of the above claims [1] to [6], wherein the content of the zeolite in the composite catalyst is 50% by mass or more and 75% by mass or less.

[0013] The present invention [8] includes a composite catalyst according to any one of the above [1] to [7], wherein the zeolite is a proton-type zeolite containing a proton as a countercation.

[0014] The present invention [9] includes a composite catalyst according to any one of the above [1] to [7], wherein the zeolite is a metal ion type zeolite containing at least one metal ion selected from the group consisting of Fe, Co, Ni, Mg, Ca, Cu, Zn, and Cr as a countercation.

[0015] The present invention

[10] includes a composite catalyst according to any one of the above [1] to [9], wherein at least one selected from the group consisting of Fe, Co, Ni, P, Mo, Mn, and Ca is supported on the zeolite.

[0016] The present invention

[11] includes a composite catalyst according to any one of the above [1] to

[10] , wherein the average primary particle size of the zeolite is 1000 nm or less.

[0017] The present invention

[12] includes a composite catalyst according to any one of the above [1] to

[11] , wherein the zeolite comprises at least one zeolite having a skeletal structure selected from the group consisting of an MFI structure, a MOR structure, a CHA structure, a FER structure, and an AEI structure.

[0018] The present invention

[13] includes the composite catalyst described in

[12] above, wherein the zeolite comprises at least one zeolite having a skeletal structure selected from the group consisting of a CHA structure and an AEI structure.

[0019] The present invention

[14] includes the composite catalyst described in

[12] above, wherein the zeolite is a zeolite having a CHA structure.

[0020] The composite catalyst of the present invention comprises a stabilized zirconia support, a solid oxide catalyst supported on the stabilized zirconia support and comprising Fe and an alkali metal active metal, and a zeolite having one skeletal structure selected from the group consisting of MFI structure, MOR structure, CHA structure, FER structure, AEI structure, BEA structure, and FAU structure. Therefore, it is possible to improve the synthesis ratio of hydrocarbons having 3 to 20 carbon atoms and to suppress the olefin ratio to paraffin in the hydrocarbons from becoming excessively high.

[0021] 1. Composite catalyst: The composite catalyst is made of CO and / or CO ２This is a catalyst for producing hydrocarbons by reacting with hydrogen. The composite catalyst can produce hydrocarbons having 3 to 20 carbon atoms. Furthermore, the ratio of olefins to paraffins in the hydrocarbons produced by the composite catalyst is not excessively high. In other words, the composite catalyst can produce short-chain paraffins having 3 to 20 carbon atoms. Note that the composite catalyst does not have to produce all hydrocarbons having 3 to 20 carbon atoms; it is sufficient if it produces at least one of these hydrocarbons. Hydrocarbons include paraffins and olefins. Paraffins are aliphatic saturated hydrocarbons, and olefins are aliphatic unsaturated hydrocarbons. Short-chain paraffins represent aliphatic saturated hydrocarbons with 20 or fewer carbon atoms.

[0022] Furthermore, the composite catalyst can produce short-chain paraffins having 3 to 20 carbon atoms. Short-chain paraffins having 3 to 20 carbon atoms are suitably used in liquefied petroleum gas (whose main components are short-chain paraffins having 3 and 4 carbon atoms), industrial fuels, and fuels for mobile vehicles.

[0023] The composite catalyst comprises a solid oxide catalyst and a zeolite. Preferably, it consists of a solid oxide catalyst and a zeolite. Specifically, the composite catalyst is a mixture of a solid oxide catalyst and a zeolite.

[0024] As will be explained in more detail later, in composite catalysts, the solid oxide catalyst is CO and / or CO ２ The zeolite reacts with hydrogen to form an intermediate for hydrocarbon synthesis, and then hydrogenates the synthesized unsaturated hydrocarbon, thus preparing the product as paraffin. In composite catalysts, the zeolite incorporates the intermediate formed by the solid oxide within its unique pores, and plays a role in adjusting the carbon number of the hydrocarbon being synthesized. In other words, by using a composite catalyst containing solid oxide and zeolite, it is possible to improve the synthesis rate of hydrocarbons with 3 to 20 carbon atoms and to suppress the excessively high ratio of olefins to paraffin in the hydrocarbon.

[0025] 1.1. Solid Oxide Catalysts Solid oxide catalysts are CO and / or CO ２This catalyst reacts with hydrogen to form an intermediate for producing hydrocarbons, and further adds hydrogen to the aliphatic unsaturated hydrocarbon (olefin) formed under the reaction to produce aliphatic saturated hydrocarbon (paraffin).

[0026] The solid oxide catalyst comprises a stabilized zirconia support and an active metal supported on the stabilized zirconia support. The solid oxide catalyst may optionally contain additives other than the stabilized zirconia support and the active metal supported on the stabilized zirconia support. Examples of additives include other support components besides the stabilized zirconia support, reaction promoters, diluents, and binders.

[0027] [Stabilized Zirconia Support] The stabilized zirconia support carries the active metal described later. The stabilized zirconia support has a tetragonal and / or cubic crystal structure in which the stabilizing element is dissolved in the zirconia. More specifically, the stabilized zirconia support has a tetragonal and / or cubic crystal structure (unit cell) mainly composed of zirconia in which at least the stabilizing element is dissolved in the zirconia.

[0028] The crystal structure of the stabilized zirconia support is mainly composed of zirconium (Zr), and at multiple lattice points of the crystal structure of the stabilized zirconia support, there are mainly Zr ions (Zr ４＋ ) will be placed.

[0029] The stabilizing elements stabilize the crystal structure of the stabilized zirconia support so that it becomes tetragonal and / or cubic.

[0030] The stabilizing element is, for example, at least one element selected from the group consisting of Y, Sm, Ca, Ce, La, Pr, Nd, Gd, Dy, and Mg. Preferably, it is at least one element selected from the group consisting of Y, Sm, and Ca. More preferably, it is Y. The stabilizing element may be used alone or in combination of two or more.

[0031] Furthermore, the stabilized zirconia support may contain, in addition to the stabilizing elements, an active metal, as described later, in solid solution.

[0032] When a stabilizing element or active metal is dissolved in the crystal structure of a stabilized zirconia support, some of the lattice points among the multiple lattice points of the crystal structure become Zr ions (Zr ４＋ ) is replaced by either an ion of a stabilizing element or an ion of an active metal.

[0033] In other words, solid solution of a stabilizing element or an active metal in a stabilized zirconia support means that the Zr ions located at the lattice points of the crystal structure are replaced by either stabilizing element ions or active metal ions. For example, solid solution of Y in a stabilized zirconia support means that the Zr ions located at the lattice points of the crystal structure are replaced by Y ions.

[0034] Therefore, each of the following is located at multiple lattice points of the stabilized zirconia support: a Zr ion, a stabilizing element ion, or an active metal ion. The crystal structure of such a stabilized zirconia support preferably includes a perovskite structure.

[0035] Such a stabilized zirconia support is represented by the following general formula (1).

[0036] General formula (1):

[0037] In general formula (1), x and y are less than 1. Also, x + y is less than 1. In general formula (1), A represents the stabilizing element and B represents the active metal. If the active metal is not solid-dissolved in the stabilized zirconia support, y is 0. α represents the valence of the stabilizing element ion and β represents the valence of the active metal ion. α and β are integers between 2 and 4. Note that general formula (1) represents the case where both the stabilizing element and the active metal are used individually.

[0038] In general formula (1), x is, for example, greater than 0, 0.10 or more, and, for example, less than 1, preferably 0.67 or less.

[0039] In general formula (1), y is, for example, 0 or more, preferably 0.01 or more, and also, for example, less than 1, preferably 0.10 or less.

[0040] Also, the interplanar spacing in the stabilized zirconia carrier varies depending on the amount of the stabilizing element dissolved in the stabilized zirconia carrier because the ionic radii of Zr ions, stabilizing element ions, and active metal ions are different. For reference, Zr ４＋ , Y ３＋ , Fe ２＋ , and Fe ３＋ have the following ionic radii. That is, Zr ４＋ : 0.079 nm, Y ３＋ : 0.090 nm, Fe ２＋ : 0.061 nm, Fe ３＋ : 0.055 nm

[0041] Specifically, when stabilizing element ions or active metal ions having an ionic radius larger than that of Zr ions are dissolved more in the stabilized zirconia carrier, the interplanar spacing in the stabilized zirconia carrier increases (expands). On the other hand, when stabilizing element ions or active metal ions having an ionic radius smaller than that of Zr ions are dissolved more in the stabilized zirconia carrier, the interplanar spacing in the stabilized zirconia carrier decreases (contracts).

[0042] The interplanar spacing of the

[111] plane in the crystal structure of the stabilized zirconia carrier is, for example, 0.2920 nm or more, preferably 0.2935 nm or more, and, for example, 0.2995 nm or less, preferably 0.2985 nm or less. The interplanar spacing of the

[111] plane in the crystal structure of stabilized zirconia in which no stabilizing element and active metal are dissolved is 0.2975 nm in the case of tetragonal zirconia and 0.2965 nm in the case of cubic zirconia.

[0043] Further, the stabilized zirconia carrier has oxygen vacancies. When a stabilizing element and an active metal are dissolved in the stabilized zirconia carrier and stabilizing element ions or active metal ions having a valence of 3 or less (divalent or trivalent) substitute for Zr ions, since Zr ions (Zr ４＋ ) are tetravalent and stabilizing element ions or active metal ions are divalent or trivalent, oxygen defects (deficiencies) occur in the crystal structure, and oxygen vacancies are formed.

[0044] Specifically, when a trivalent stabilizing element ion and / or active metal ion is substituted with a Zr ion, oxygen vacancies are formed in the stabilized zirconia support according to the Kregor-Bink formula shown in general formula (2) below, and when a divalent stabilizing element ion and / or active metal ion is substituted with a Zr ion, oxygen vacancies are formed in the stabilized zirconia support according to the Kregor-Bink formula shown in general formula (3) below.

[0045] General formula (2):

[0046] General formula (3):

[0047] Furthermore, when tetravalent stabilizing element ions and / or active metal ions are substituted for Zr ions, oxygen vacancies are not formed in the stabilized zirconia support because their valencies are the same.

[0048] In solid oxide catalysts, the atomic percentage of each atom is an atomic percentage based on its elemental state and is calculated from the amount of raw materials charged (salts of zirconia and / or Zr, salts of stabilizing elements, and salts of active metals) (the same applies hereinafter).

[0049] In the following, "active metal" refers to the sum of the active metal supported on the stabilized zirconia carrier and the active metal dissolved in the stabilized zirconia carrier (the same applies hereafter). Furthermore, if the active metal is in the state of a metal oxide, "atoms in the active metal" refers to the atoms other than oxygen (specifically, metal atoms) among the atoms contained in the active metal (the same applies hereafter).

[0050] The atomic ratio of Zr (= Zr / (Zr + stabilizing element) × 100) relative to the total sum of Zr and stabilizing elements constituting the stabilized zirconia support is, for example, 40 atomic% or more, preferably 50 atomic% or more, more preferably 60 atomic% or more, even more preferably 65 atomic% or more, and also, for example, 90 atomic% or less, preferably 80 atomic% or less, and more preferably 70 atomic% or less.

[0051] If the atomic ratio of Zr to the total sum of Zr and stabilizing elements constituting the stabilized zirconia support is within the above range, then a tetragonal and / or cubic crystal structure can be reliably formed in the stabilized zirconia support.

[0052] The atomic ratio of the stabilizing element (= stabilizing element / (Zr + stabilizing element) × 100) relative to the total sum of Zr and stabilizing elements constituting the stabilized zirconia support is, for example, 10 atomic% or more, preferably 20 atomic% or more, more preferably 30 atomic% or more, and also, for example, 60 atomic% or less, preferably 50 atomic% or less, more preferably 40 atomic% or less, and even more preferably 35 atomic% or less.

[0053] If the atomic percentage of the stabilizing element is within the above range relative to the total sum of Zr and the stabilizing element constituting the stabilized zirconia support, oxygen vacancies can be formed well in the stabilized zirconia support, and the stabilized zirconia support can reliably attract oxygen atoms in carbon dioxide molecules. Therefore, catalytic activity can be further improved, and short-chain paraffins can be efficiently produced from carbon dioxide.

[0054] The atomic ratio of Zr (= Zr / (Zr + stabilizing element + active metal) × 100) to the total sum of Zr, stabilizing elements, and active metals constituting the stabilized zirconia support is, for example, 1.0 atomic% or more, preferably 3.0 atomic% or more, more preferably 5.0 atomic% or more, even more preferably 8.0 atomic% or more, or, for example, 50 atomic% or less, preferably 30 atomic% or less, more preferably 25 atomic% or less, even more preferably 20 atomic% or less, and particularly preferably 15 atomic% or less.

[0055] If the atomic ratio of Zr to the total sum of Zr, stabilizing elements, and active metal constituting the stabilized zirconia support is equal to or greater than the lower limit, then a tetragonal and / or cubic crystal structure can be reliably formed in the stabilized zirconia support. Furthermore, if the atomic ratio of Zr to the total sum of Zr, stabilizing elements, and active metal constituting the stabilized zirconia support is equal to or less than the upper limit, then a sufficient proportion of active metal necessary for catalytic activity can be secured.

[0056] The atomic ratio of the stabilizing element (= stabilizing element / (Zr + stabilizing element + active metal) × 100) relative to the total amount of Zr, stabilizing elements, and active metal constituting the stabilized zirconia support is, for example, 1.0 atomic% or more, preferably 2.0 atomic% or more, more preferably 3.0 atomic%, and also, for example, 30 atomic% or less, preferably 15 atomic% or less, more preferably 10 atomic% or less, and even more preferably 7.0 atomic% or less.

[0057] If the atomic ratio of the stabilizing element to the total sum of Zr, the stabilizing element, and the active metal constituting the stabilized zirconia support is greater than or equal to the lower limit, the tetragonal and / or cubic crystal structures can be reliably stabilized. Furthermore, if the atomic ratio of the stabilizing element to the total sum of Zr, the stabilizing element, and the active metal constituting the stabilized zirconia support is less than or equal to the upper limit, inhibition of catalytic activity due to oxide formation by excess stabilizing elements can be suppressed.

[0058] [Activated Metal] The activated metal is supported on the stabilized zirconia carrier described above. Alternatively, the activated metal may be in solid solution on the stabilized zirconia carrier.

[0059] The active metal can be, for example, in the metallic state or in the metal oxide state. From the viewpoint of catalytic activity, the metallic state is preferred.

[0060] The active metals include Fe and alkali metals. Preferably, they include metallic Fe and alkali metals.

[0061] If the active metal includes Fe and alkali metals, it is possible to improve the synthesis ratio of hydrocarbons with 3 to 20 carbon atoms and to suppress the excessively high ratio of olefins to paraffins in the hydrocarbons. Specifically, CO ２ When producing hydrocarbons with 3 to 20 carbon atoms from raw materials containing hydrogen via CO, ２This improves the conversion rate and allows for a relatively low proportion of CO, an intermediate product, remaining in the final product. Furthermore, hydrogen can be added to the aliphatic unsaturated hydrocarbon (olefin) formed during the reaction, resulting in a relatively low olefin-to-paraffin ratio in the hydrocarbon.

[0062] Examples of alkali metals include Na and K. K is preferred. Alkali metals may be used individually or in combination of two or more.

[0063] The active metal may include other active metals besides Fe and alkali metals. Examples of other active metals include Co, Cu, and Ru. Preferably, Co is used.

[0064] The active metal is preferably composed of Fe and K, or Fe, Co, and K. More preferably, it is composed of Fe and K.

[0065] The atomic ratio of Fe to the total active metals (= Fe / active metals × 100) is, for example, 50 atomic percent or more, preferably 65 atomic percent or more, more preferably 80 atomic percent or more, even more preferably 90 atomic percent or more, and also, for example, less than 100 atomic percent, preferably 98 atomic percent or less, more preferably 95 atomic percent or less.

[0066] In other words, the main component of the active metal is Fe. The fact that the main component of the active metal is Fe means that the atomic proportion of Fe (= Fe / active metal × 100) relative to the total amount of active metals is 50 atomic percent or more.

[0067] The atomic ratio of alkali metals to the total amount of active metals (= alkali metals / active metals × 100) is, for example, 1.0 atomic% to 30 atomic%, preferably 3.0 atomic% to 15 atomic%, and more preferably 5.0 atomic% to 10 atomic%.

[0068] The atomic ratio of alkali metals to the total amount of active metals (= alkali metals / active metals × 100) is, for example, 1.0 atomic% or more, preferably 3.0 atomic% or more, more preferably 5.0 atomic% or more, and also, for example, 30 atomic% or less, preferably 15 atomic% or less, more preferably 10 atomic% or less.

[0069] The atomic ratio of Fe and alkali metals combined to the total number of active metals (= (Fe + alkali metal) / active metal × 100) is, for example, 50 atomic% or more, preferably 70 atomic% or more, more preferably 80 atomic% or more, even more preferably 90 atomic% or more, particularly preferably 95 atomic% or more, and most preferably 100 atomic%.

[0070] If the total atomic ratio of Fe and alkali metals to the total number of active metals is above the above lower limit, it is possible to improve the synthesis rate of hydrocarbons with 3 to 20 carbon atoms and to suppress the excessively high ratio of olefins to paraffins in hydrocarbons. Specifically, CO ２ When producing hydrocarbons with 1 to 20 carbon atoms from raw materials containing hydrogen via CO, ２ This improves the conversion rate and allows for a relatively low proportion of CO, an intermediate product, remaining in the final product. Furthermore, hydrogen can be added to the unsaturated hydrocarbons formed during the reaction, resulting in a relatively low olefin-to-paraffin ratio in the hydrocarbons.

[0071] When the active metal includes other active metals besides Fe and alkali metals, the atomic ratio of the other active metals to the total active metals (= other active metals / active metals × 100) is greater than 0 atomic%, preferably 5.0 atomic% or more, more preferably 10 atomic% or more, even more preferably 15 atomic% or more, and also, for example, 40 atomic% or less, preferably 30 atomic% or less, and more preferably 20 atomic% or less.

[0072] The atomic ratio of Fe and alkali metals to the total sum of Zr, stabilizing elements, and active metals constituting the stabilized zirconia support (= (Fe + alkali metal) / (Zr + stabilizing elements + active metal) × 100) is, for example, 30 atomic% to 98 atomic%, preferably 50 atomic% to 95 atomic%, more preferably 55 atomic% to 92 atomic%, even more preferably 75 atomic% to 90 atomic%, and particularly preferably 80 atomic% to 90 atomic%.

[0073] The atomic ratio of Fe and alkali metals to the total sum of Zr, stabilizing elements, and active metals constituting the stabilized zirconia support (= (Fe + alkali metal) / (Zr + stabilizing elements + active metal) × 100) is, for example, 30 atomic% or more, preferably 50 atomic% or more, more preferably 55 atomic% or more, even more preferably 75 atomic% or more, particularly preferably 80 atomic% or more, and also, for example, 98 atomic% or less, preferably 95 atomic% or less, more preferably 92 atomic% or less, and even more preferably 90 atomic% or less.

[0074] If the total atomic ratio of Fe and alkali metals to the total sum of Zr, stabilizing elements, and active metals constituting the stabilized zirconia support is above the lower limit, catalytic activity can be improved. Furthermore, if the total atomic ratio of Fe and alkali metals to the total sum of Zr, stabilizing elements, and active metals constituting the stabilized zirconia support is below the upper limit, the decrease in dispersibility of Fe and alkali metals due to aggregation of Fe and alkali metals can be suppressed.

[0075] The content of the solid oxide catalyst in the composite catalyst is, for example, 10% to 70% by mass, preferably 20% to 60% by mass, and more preferably 25% to 50% by mass.

[0076] The content of the solid oxide catalyst in the composite catalyst is, for example, 10% by mass or more, preferably 20% by mass or more, more preferably 25% by mass or more, and also, for example, 70% by mass or less, preferably 60% by mass or less, more preferably 50% by mass or less.

[0077] If the content of the solid oxide catalyst in the composite catalyst is above the lower limit mentioned above, it is possible to improve the synthesis rate of hydrocarbons having 3 to 20 carbon atoms and to suppress the excessively high ratio of olefins to paraffins in the hydrocarbons. Furthermore, if the content of the solid oxide catalyst in the composite catalyst is below the upper limit mentioned above, it is possible to ensure a sufficient amount of zeolite is incorporated, thereby further improving the synthesis rate of hydrocarbons having 3 to 20 carbon atoms.

[0078] 1.2. Zeolites Zeolites are crystalline aluminosilicates. Crystalline aluminosilicates consist of crystals with a three-dimensional network structure in which aluminum (Al) and silicon (Si) are used as the skeletal metals (hereinafter referred to as T atoms), and Al and Si are bonded via oxygen (O).

[0079] In this embodiment, the zeolite includes a zeolite-like substance. The zeolite-like substance contains a T atom other than Al and Si. Specifically, examples of zeolite-like substances include silicoaluminophosphate (SAPO) and aluminophosphate (AlPO) containing phosphorus (P).

[0080] In this embodiment, the zeolite preferably does not contain any T atoms other than Al and Si. That is, it has a three-dimensional network structure in which Al and Si are bonded via O, with Al and Si being the T atoms.

[0081] Zeolites include, for example, zeolites having a pore structure with 12 or fewer oxygen rings. Preferably, zeolites having a pore structure with 10 or fewer oxygen rings. More preferably, zeolites having a pore structure with 8 oxygen rings. The value of n (where n is an integer) in zeolites having n oxygen rings indicates the pore with the largest number of oxygen atoms among those composed of oxygen and skeletal metal forming the zeolite's skeletal structure.

[0082] The zeolite comprises at least one zeolite having a skeletal structure selected from the group consisting of MFI structure, MOR structure, CHA structure, FER structure, AEI structure, BEA structure, and FAU structure. Preferably, it comprises at least one zeolite having a skeletal structure selected from the group consisting of MFI structure, MOR structure, CHA structure, FER structure, and AEI structure. More preferably, it comprises at least one zeolite having a skeletal structure selected from the group consisting of CHA structure and AEI structure. Even more preferably, it comprises at least one zeolite having a CHA structure. Note that the above FAU structure is a Y-type FAU structure.

[0083] If the zeolite includes at least one zeolite having a skeletal structure selected from the group consisting of MFI structure, MOR structure, CHA structure, FER structure, AEI structure, BEA structure, and FAU structure, the carbon number of the hydrocarbon produced can be adjusted. As a result, the synthesis ratio of hydrocarbons with 3 to 20 carbon atoms can be further improved. In particular, if the zeolite includes at least one zeolite having a skeletal structure selected from the group consisting of MFI structure, MOR structure, CHA structure, FER structure, and AEI structure, the carbon number of the hydrocarbon produced can be adjusted. As a result, the synthesis ratio of hydrocarbons with 3 to 20 carbon atoms can be further improved.

[0084] Furthermore, "zeolite" means that the zeolite includes at least one skeletal structure selected from the group consisting of MFI structure, MOR structure, CHA structure, FER structure, AEI structure, BEA structure, and FAU structure, and refers to a physical mixture of a zeolite having the above skeletal structure and a zeolite having another skeletal structure, a mixed crystal of a zeolite having the above skeletal structure and a zeolite having another skeletal structure, and a combination thereof.

[0085] Furthermore, the zeolite mainly comprises a zeolite having one skeletal structure selected from the group consisting of, for example, MFI structure, MOR structure, CHA structure, FER structure, AEI structure, BEA structure, and FAU structure. Preferably, the zeolite mainly comprises a zeolite having one skeletal structure selected from the group consisting of MFI structure, MOR structure, CHA structure, FER structure, and AEI structure. More preferably, the zeolite mainly comprises a zeolite having one skeletal structure selected from the group consisting of CHA structure and AEI structure. Even more preferably, the zeolite mainly comprises a zeolite having a CHA structure.

[0086] If the zeolite primarily contains a zeolite having one skeletal structure selected from the group consisting of MFI structure, MOR structure, CHA structure, FER structure, AEI structure, BEA structure, and FAU structure, the carbon number of the hydrocarbon produced can be controlled more reliably. As a result, the composite catalyst can further improve the synthesis ratio of hydrocarbons with 3 to 20 carbon atoms.

[0087] Furthermore, "containing as a main component a zeolite having one skeletal structure selected from the group consisting of MFI structure, MOR structure, CHA structure, FER structure, AEI structure, BEA structure, and FAU structure" means a mixture of a zeolite having the above skeletal structure and a zeolite having another skeletal structure, a mixed crystal of a zeolite having the above skeletal structure and a zeolite having another skeletal structure, or a combination thereof, in which the zeolite having the above skeletal structure accounts for 50% by mass or more of the total amount of zeolite.

[0088] When the zeolite contains as a main component a zeolite having one skeletal structure selected from the group consisting of MFI structure, MOR structure, CHA structure, FER structure, AEI structure, BEA structure, and FAU structure, the proportion of the zeolite having the above skeletal structure in the total amount of zeolite is preferably 60% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, particularly preferably 95% by mass or more, and most preferably 98% by mass or more.

[0089] Furthermore, if the zeolite mainly contains a zeolite having one skeletal structure selected from the group consisting of MFI structure, MOR structure, CHA structure, FER structure, AEI structure, BEA structure, and FAU structure, it is permissible for the seed crystal zeolite (described later) used in the synthesis of the zeolite to be inevitably mixed in as a mixed crystal if it has a skeletal structure other than the above-mentioned structures.

[0090] Furthermore, the zeolite consists of at least one selected from the group consisting of, for example, zeolite having an MFI structure, zeolite having a MOR structure, zeolite having a CHA structure, zeolite having a FER structure, zeolite having an AEI structure, zeolite having a BEA structure, and zeolite having a FAU structure. Preferably, it consists of at least one selected from the group consisting of zeolite having an MFI structure, zeolite having a MOR structure, zeolite having a CHA structure, zeolite having a FER structure, and zeolite having an AEI structure. More preferably, it consists of at least one selected from the group consisting of zeolite having a CHA structure and zeolite having an AEI structure. Even more preferably, it consists of zeolite having a CHA structure.

[0091] If the zeolite is selected from at least one of the group consisting of zeolites having an MFI structure, zeolites having a MOR structure, zeolites having a CHA structure, zeolites having a FER structure, zeolites having an AEI structure, zeolites having a BEA structure, and zeolites having a FAU structure, the carbon number of the hydrocarbon produced can be adjusted more reliably. As a result, the composite catalyst can further improve the synthesis ratio of hydrocarbons with 3 to 20 carbon atoms.

[0092] Furthermore, the term "zeolite" means, for example, at least one selected from the group consisting of zeolites having an MFI structure, zeolites having a MOR structure, zeolites having a CHA structure, zeolites having a FER structure, zeolites having an AEI structure, zeolites having a BEA structure, and zeolites having a FAU structure. This includes using any one of the above-mentioned zeolites having a skeletal structure alone, and using two or more of the above-mentioned zeolites having a skeletal structure in combination (including physically mixed zeolites, mixed crystals, and combinations thereof).

[0093] Furthermore, zeolites having an MOR structure, a BEA structure, and a FAU structure have a pore structure with 12 oxygen rings. Zeolites having an MFI structure and a FER structure have a pore structure with 10 oxygen rings. Zeolites having a CHA structure and a AEI structure have a pore structure with 8 oxygen rings.

[0094] The regular skeletal structure of zeolites and zeolite-like materials is identified by the structural code (hereinafter referred to as "structural code") defined by the Structure Commission of the International Zeolite Association. For example, the CHA structure is identified as the structural code "CHA". The skeletal structure of zeolites can be identified by comparing it with the XRD patterns of each structure described in Collection of simulated XRD powder patterns for zeolites, Fifth revised edition, (2007).

[0095] In this embodiment, "zeolite having a CHA structure" and other "zeolite having a ~ structure" refer to a zeolite having the skeletal structure of the zeolite with the above-mentioned structural code.

[0096] As mentioned above, zeolites are crystalline aluminosilicates, and at least Al and Si are present as T atoms. In other words, zeolites are silicates in which all T atoms are Si, and some Si ４＋ Al ３＋ Substituted with and / or other ions. At least Al ３＋ is Si ４＋ Because of their lower valence, zeolites develop a negative charge. To maintain this charge neutral, zeolites have cations (countercations) near the Al atoms (within the pores).

[0097] Examples of zeolite countercations include alkali metal ions and ammonium ions (NH₄). ４＋ ), and proton (H ＋ Examples of alkali metal ions include sodium ions (Na ＋ ) and potassium ions (K ＋ ) are some examples.

[0098] Examples of zeolites include proton-type zeolites containing a proton as a countercation, sodium-type zeolites containing a sodium ion as a countercation, and ammonium-type zeolites containing an ammonium ion as a countercation. Proton-type zeolites are preferred.

[0099] Furthermore, some or all of the countercations in zeolites can be ion-exchanged, meaning they can be exchanged for other metal ions. In this case, the zeolite will contain the metal ions introduced through ion exchange as countercations. Note that "other metal ions" refers to metal ions other than alkali metal ions.

[0100] In other words, zeolites can also include metal ion type zeolites, which contain, for example, at least one metal ion selected from the group consisting of Fe, Co, Ni, Mg, Ca, Cu, Zn, and Cr as a counter cation.

[0101] Furthermore, proton-type zeolites containing protons as countercations, sodium-type zeolites containing sodium ions as countercations, and ammonium-type zeolites containing ammonium ions as countercations can each be prepared by ion-exchanging some or all of the countercations in zeolites containing different countercations.

[0102] The zeolite may, for example, support a metal and / or a metal oxide. Preferably, the zeolite may support a metal.

[0103] Examples of metals supported on zeolites include Fe, Co, Ni, P, Mo, Mn, and Ca. The metals supported on the zeolite may be used individually or in combination of two or more. That is, at least one selected from the group consisting of Fe, Co, Ni, P, Mo, Mn, and Ca is supported on the zeolite. Note that a distinction is made between zeolites with P supported on them and zeolites containing P as a T atom.

[0104] The ratio of the metal supported on the zeolite to the zeolite (amount of metal supported / mass of zeolite × 100) is, for example, 0.025% by mass or more, preferably 0.05% by mass or more, and for example, 60% by mass or less, preferably 50% by mass or less.

[0105] The ion exchange in zeolites described above (ion exchange of zeolite countercations for metal ions) and the metal support on zeolites described above can be used in combination. Specifically, metal can be supported on metal ion type zeolites. The metal ions in the metal ion type zeolite and the supported metal may be the same element or different elements.

[0106] The pore size of the zeolite is not particularly limited, and can be, for example, 0.1 nm or larger, preferably 0.3 nm or larger, more preferably 0.4 nm or larger, or, for example, 3.0 nm or smaller, preferably 1.0 nm or smaller, more preferably 0.8 nm or smaller, and even more preferably 0.7 nm or smaller. In zeolites having an n-membered oxygen ring, the pore size of the zeolite tends to increase as n increases (i.e., as the number of oxygen atoms forming the zeolite's skeletal structure increases).

[0107] If the pore size of the zeolite is within the above range, it is possible to improve the synthesis ratio of hydrocarbons with 3 to 20 carbon atoms.

[0108] Note that the pore size of a zeolite refers to the crystallographic channel diameter as defined by the International Zeolite Association.

[0109] The average primary particle size of the zeolite is, for example, 10 nm or more, preferably 30 nm or more, more preferably 50 nm or more, and also, for example, 3000 nm or less, preferably 2000 nm or less, more preferably 1000 nm or less, and even more preferably 500 nm or less.

[0110] If the average primary particle size of the zeolite is within the above range, it is possible to improve the synthesis ratio of hydrocarbons with 3 to 20 carbon atoms.

[0111] The average primary particle size of zeolite can be measured by observation using a scanning electron microscope.

[0112] The Si / Al ratio (molar ratio of silicon to aluminum) of the zeolite is, for example, 2 or more, preferably 5 or more, more preferably 8 or more, even more preferably 9 or more, or, for example, 1000 or less, preferably 500 or less, more preferably 300 or less, even more preferably 150 or less. Alternatively, the Si / Al ratio (molar ratio of silicon to aluminum) of the zeolite may be, for example, 50 or less, preferably 30 or less, more preferably 20 or less, even more preferably 15 or less, and particularly preferably 12 or less.

[0113] The Si / Al ratio of zeolite can be determined by X-ray fluorescence spectroscopy (XRF).

[0114] The specific surface area of ​​zeolite is not particularly limited, but for example, 100 m ２ / g or more, preferably 300m ２ / g or more, and for example, 1000m ２ Less than or equal to 800mg ２ It is less than or equal to / g.

[0115] The specific surface area of ​​zeolite can be measured using the BET method.

[0116] The zeolite content in the composite catalyst is, for example, 30% to 90% by mass, preferably 40% to 80% by mass, more preferably 50% to 75% by mass, and even more preferably 60% to 70% by mass.

[0117] The zeolite content in the composite catalyst is, for example, 30% by mass or more, preferably 40% by mass or more, more preferably 50% by mass or more, even more preferably 60% by mass or more, and also, for example, 90% by mass or less, preferably 80% by mass or less, more preferably 75% by mass or less, and even more preferably 70% by mass or less.

[0118] If the zeolite content in the composite catalyst is above the lower limit mentioned above, the synthesis ratio of hydrocarbons with 3 to 20 carbon atoms can be further improved. Furthermore, if the zeolite content in the composite catalyst is below the upper limit mentioned above, the amount of solid oxide catalyst can be ensured, thereby improving the synthesis ratio of hydrocarbons with 3 to 20 carbon atoms and preventing the olefin ratio to paraffin in the hydrocarbons from becoming excessively high.

[0119] 2. Method for Manufacturing Composite Catalysts Next, a method for manufacturing composite catalysts will be described.

[0120] A method for producing a composite catalyst includes, for example, a step of preparing a solid oxide catalyst precursor and a zeolite (preparation step), a step of mixing the solid oxide catalyst precursor and the zeolite to prepare a composite catalyst precursor (mixing step), and a step of pre-treating the composite catalyst precursor (pre-treatment step).

[0121] 2.1. Preparation Process In the preparation process, the solid oxide catalyst precursor and the zeolite are prepared.

[0122] (Preparation of solid oxide catalyst precursor) The solid oxide catalyst precursor is, for example, a raw material component (zirconia (ZrO ２ The process includes the steps of: preparing a mixture by mixing (a mixture preparation step) (a salt of Zr, a salt of the above-mentioned stabilizing element, and a salt of an active metal other than an alkali metal); preparing a solid oxide catalyst material by calcining the mixture (a first calcination step); preparing a dispersion by adding the solid oxide catalyst material to an aqueous solution of an alkali metal salt (a dispersion preparation step); and preparing a solid oxide catalyst precursor by calcining the dispersion (a second calcination step).

[0123] First, as a carrier component, zirconia (ZrO ２ A mixture is prepared by mixing, for example, a salt of Zr and / or Zr, a salt of a stabilizing element, and a salt of an active metal other than an alkali metal, such that the atomic proportions of each atom (Zr, the stabilizing element, and the active metal other than an alkali metal) are within the above range (mixture preparation step).

[0124] Examples of zirconia include low-crystallinity ZrO ２ Examples include fine particles. Also, ZrO ２ The fine particles may be dispersed in water in a dispersion (zirconia hydrosol). Commercial zirconia products may be used for this purpose. For example, a commercially available product is the zirconia hydrosol "ZSL-10A" (manufactured by Daiichi Rare Elements Chemical Industry Co., Ltd., Zr: 10% by mass, pH = 7.2).

[0125] Examples of Zr salts include Zr nitrates (e.g., zirconium nitrate (Zr(NO) ３ ) ４ ), zirconium nitrate (ZrO(NO) ３ )２ )), Zr hydrochloride (e.g., zirconium chloride (ZrCl) ２ O)), and Zr acetates (e.g., zirconium acetate (ZrO(C)) ２ H ３ O ２ ) ２ Examples include: )) The salts of Zr may be used alone or in combination of two or more.

[0126] Such Zr salts can also be commercially available, and examples of commercially available products include zirconium nitrate pentahydrate (manufactured by BOC Science Co., Ltd.), zirconium nitrate oxide dihydrate (manufactured by Kanto Chemical Co., Ltd.), zirconium chloride oxide octahydrate (manufactured by Kanto Chemical Co., Ltd.), and zirconium acetate oxide (manufactured by Daiichi Rare Elements Chemical Industry Co., Ltd.).

[0127] Examples of salts of stabilizing elements include nitrates and chlorides of stabilizing elements. Preferably, nitrates of stabilizing elements are used. More preferably, nitrates of Y, Sm, and Ca are used. Even more preferably, nitrate of Y is used. Salts of stabilizing elements may be used alone or in combination of two or more. Commercially available salts of stabilizing elements can also be used.

[0128] Examples of salts of active metals other than alkali metals include nitrates and chlorides of active metals other than alkali metals. Preferably, nitrates of active metals other than alkali metals are used. More preferably, nitrates of Fe and Co are used. Even more preferably, nitrates of Fe are used. The salts of active metals may be used alone or in combination of two or more. Commercially available salts of active metals other than alkali metals can also be used.

[0129] To an aqueous solution of zirconia and / or Zr salt, salts of active metals other than alkali metals and salts of stabilizing elements are added such that the atomic proportions of each atom (Zr, stabilizing elements, and active metals other than alkali metals) are within the above range, and the mixture is stirred to form a homogeneous slurry.

[0130] Next, the slurry is heated, for example, in a constant-temperature drying oven to volatilize excess moisture and prepare a hard slurry (mixture) containing a salt of zirconia and / or Zr, a salt of a stabilizing element, and a salt of an active metal. The heating temperature of the slurry is, for example, 100°C to 300°C, preferably 150°C to 200°C. The heating time of the slurry is, for example, 0.5 hours to 10 hours, preferably 1 hour to 3 hours.

[0131] Next, the hard slurry (mixture) is stirred as necessary, and then fired in a heating furnace such as an electric furnace to prepare a solid oxide catalyst material (first firing step). The firing temperature is, for example, 550°C to 800°C, preferably 600°C to 700°C. The firing time is, for example, 1 hour to 24 hours, preferably 3 hours to 20 hours.

[0132] If the firing temperature is above the lower limit, the crystal structure of the stabilized zirconia support can be reliably made tetragonal and / or cubic, and if the firing temperature is below the upper limit, it is possible to suppress an excessive decrease in the specific surface area of ​​the stabilized zirconia support and a decrease in catalytic activity.

[0133] After the first firing process, the solid oxide catalyst material may be crushed in a mortar and pestle or similar device and sieved if necessary. The sieve opening should be, for example, 100 μm or less.

[0134] Next, an aqueous solution of an alkali metal salt is prepared, and the above-mentioned solid oxide catalyst material is added and stirred to prepare a dispersion (dispersion preparation step). After preparing the dispersion, the system may be evacuated to expel any remaining air from the pores of the solid oxide catalyst material. The evacuation time is, for example, 4 to 24 hours.

[0135] Subsequently, the dispersion is calcined to prepare a solid oxide catalyst precursor (second calcination step). The calcination temperature is, for example, 550°C to 800°C, preferably 600°C to 700°C. The calcination time is, for example, 1 hour to 24 hours, preferably 3 hours to 20 hours.

[0136] After the second calcination step, the solid oxide catalyst precursor may be crushed in a mortar and pestle or similar device and sieved if necessary. The sieve opening should be, for example, 100 μm or less.

[0137] The solid oxide catalyst precursor is prepared as described above.

[0138] Although the above-mentioned solid oxide catalyst precursor is in particulate form, it may be formed into a predetermined shape (e.g., cylindrical, prismatic, or hollow cylindrical shape) by pressurizing it, for example.

[0139] Furthermore, in the preparation of the solid oxide catalyst precursor, the above-mentioned additives may be added in the mixture preparation step or the dispersion preparation step.

[0140] (Preparation of zeolite) Zeolite is prepared by a commonly used hydrothermal synthesis method.

[0141] In this embodiment, first, a mixture is prepared by adding an alkali metal source, an organic structure-regulating agent, and a seed crystal zeolite to water and mixing them. Note that water may be added separately, and an aqueous solution containing the dissolved alkali metal source and / or an aqueous solution containing the dissolved organic structure-regulating agent may be used.

[0142] Examples of alkali metal sources include alkali metal hydroxides. Preferably, sodium hydroxide and potassium hydroxide are used. The alkali metal sources may be used alone or in combination of two or more.

[0143] Organic structure-determining agents can promote the crystallization of zeolites having a desired skeletal structure. The organic structure-determining agent is not particularly limited as long as it is a compound that promotes the crystallization of zeolites having a desired skeletal structure. Examples of organic structure-determining agents used in producing zeolites having a CHA structure include N,N,N-trialkyl-1-adamantanammonium, N,N,N-trialkylbenzylammonium, and 1-adamantylamine. Preferably, N,N,N-trialkyl-1-adamantanammonium is used. More preferably, N,N,N-trimethyl-1-adamantanammonium is used. The organic structure-determining agents may be used alone or in combination of two or more.

[0144] Seed crystal zeolite is a raw material used in the crystallization of zeolite having a desired skeletal structure. Examples of seed crystal zeolite include zeolite having the same skeletal structure as the desired zeolite. However, the seed crystal zeolite does not necessarily have to have the same skeletal structure as the desired zeolite. Furthermore, seed crystal zeolite may be used alone or in combination of two or more types.

[0145] The Si / Al ratio of the seed crystal zeolite is not particularly limited and can be adjusted as appropriate within the range in which the desired zeolite can be obtained. For example, the Si / Al ratio of the seed crystal zeolite is 2 to 1000. Also, the average primary particle size of the seed crystal zeolite is not particularly limited and can be adjusted as appropriate within the range in which the desired zeolite can be obtained. The average primary particle size of the seed crystal zeolite can be adjusted by grinding or other processes.

[0146] Furthermore, an aluminum source and a silica source may be added to the mixture in place of, or along with, the seed crystal zeolite. Depending on the desired zeolite, a phosphorus source may also be added.

[0147] The aluminum source is a raw material compound that becomes the aluminum atoms constituting the zeolite. Examples of aluminum sources include aluminum sulfate, aluminum nitrate, pseudoboehmite, aluminum alkoxide, aluminum hydroxide, alumina sol, and sodium aluminate. Aluminum hydroxide is preferred. The aluminum source may be used alone or in combination of two or more.

[0148] The silica source is a raw material compound that becomes the silicon atoms constituting the zeolite. Examples of silica sources include fumed silica, silica sol (colloidal silica), silica gel, silicates such as silicon dioxide and water glass, silicon alkoxides such as tetraethoxyorthosilicate and tetramethoxysilane, and silicon halides. Silica sol (colloidal silica) is preferred. The silica source may be used alone or in combination of two or more types.

[0149] The amounts of aluminum source (solids) and silica source (solids) added are adjusted as appropriate within the range where the desired zeolite parameters (e.g., Si / Al ratio) can be obtained.

[0150] Phosphorus sources are raw material compounds that become the phosphorus atoms that make up zeolites. Examples of phosphorus sources include phosphoric acid, phosphorous acid, hypophosphorous acid, pyrophosphate, polyphosphate, ammonium monohydrogen phosphate, ammonium dihydrogen phosphate, triammonium phosphate, ammonium superphosphate, ammonium hypophosphate, phosphorus pentoxide, and phosphines.

[0151] Next, the resulting mixture is crystallized by hydrothermal synthesis in a heated and pressurized vessel such as an autoclave.

[0152] The heating temperature is, for example, 100°C to 250°C. The pressure is, for example, 1 MPa to 30 MPa. The heating and pressurizing time is, for example, 1 hour to 72 hours.

[0153] Next, the crystallized product is filtered, washed with water, and dried. Then, it is calcined to obtain powdered zeolite.

[0154] The drying temperature is, for example, 110°C to 170°C. The drying time is 1 hour to 24 hours.

[0155] The firing temperature is, for example, 350°C to 800°C, preferably 450°C to 700°C. The firing time is, for example, 1 hour to 24 hours, preferably 2 hours to 20 hours.

[0156] After calcination, the zeolite is subjected to ion exchange as needed. Known methods can be used for ion exchange in the zeolite. Specifically, to obtain proton-type zeolite from sodium-type zeolite, first, sodium-type zeolite is added to an aqueous solution of ammonium salt (e.g., ammonium nitrate) to form ammonium-type zeolite. Then, proton-type zeolite is obtained by calcination under air circulation.

[0157] After firing, the zeolite is loaded with metal as needed. Known methods can be used to load the metal onto the zeolite. Examples of such methods include impregnation, coprecipitation, kneading, and alkoxide deposition.

[0158] Specifically, metal is supported on zeolite using the impregnation method known as impregnation wetness. First, a predetermined amount of zeolite is placed in a round-bottom flask, and the flask is evacuated for 1 to 4 hours. After evacuating, a solution of metal salt (metal salt of the metal to be supported) dissolved in pure water is added, and the zeolite and metal salt solution are mixed. At this time, the mixture is shaken until the zeolite is uniformly colored by the metal salt solution and no longer adheres to the flask walls in a wet state. Next, the mixture is transferred to a crucible or similar container and fired to obtain zeolite with the metal supported. The firing temperature and firing time are as described above.

[0159] In this way, a zeolite for use in composite catalysts can be obtained.

[0160] 2.2. Mixing Process In the mixing process, the above-mentioned solid oxide catalyst precursor and the above-mentioned zeolite are mixed.

[0161] Specifically, the solid oxide catalyst precursor and zeolite are weighed and mixed so that the solid oxide catalyst and zeolite in the composite catalyst have the above-mentioned content ratio. The mixing method is not particularly limited, as long as it ensures that the solid oxide catalyst precursor and zeolite are thoroughly mixed.

[0162] 2.3. Pretreatment Process The pretreatment process activates the composite catalyst precursor (solid oxide catalyst precursor). Specifically, it reduces the active metal in the solid oxide catalyst precursor contained in the composite catalyst precursor.

[0163] As a pretreatment method, a hydrogen-based method (H ２ Processing), a method using a mixed gas of hydrogen and carbon monoxide (H ２ Methods include carbon monoxide treatment (CO treatment) and carbon monoxide treatment.

[0164] (H ２Processing) H ２ In the process, for example, the composite catalyst precursor is packed into a predetermined container, heated to the reduction temperature using a heater such as an electric tubular furnace, and hydrogen gas is circulated through the container. ２ In the process, H, which will be described later, ２ Unlike the CO treatment, the hydrogen gas does not contain CO. ２ The process may include other gases (excluding CO) in the hydrogen gas. Preferably, it does not include any gases other than hydrogen gas.

[0165] The reduction temperature is, for example, 200°C or higher, preferably 300°C or higher, and also, for example, 800°C or lower, preferably 600°C or lower. The reduction time is, for example, 2 hours or more, preferably 3 hours or more, and also, for example, 24 hours or less, preferably 12 hours or less.

[0166] The hydrogen gas flow rate per gram of composite catalyst precursor is, for example, 50 mL / min or more, preferably 100 mL / min or more, and for example, 1000 mL / min or less, preferably 800 mL / min or less.

[0167] (H ２ (+CO treatment) H ２ In the +CO treatment, for example, a composite catalyst precursor is packed into a predetermined container and heated to the reduction temperature using a heater such as an electric tubular furnace, while a mixed gas of hydrogen and carbon monoxide is circulated through the container. ２ In the +CO treatment, the mixed gas of hydrogen and carbon monoxide may contain other gases. ２ The mixed gas used for the CO treatment is preferably a mixed gas consisting of hydrogen, carbon monoxide, and argon.

[0168] The reduction temperature is, for example, 200°C or higher, preferably 250°C or higher, and also, for example, 500°C or lower, preferably 400°C or lower. The reduction time is, for example, 2 hours or more, preferably 3 hours or more, and also, for example, 10 hours or less, preferably 5 hours or less.

[0169] The flow rate of the mixed gas containing hydrogen and carbon monoxide per gram of composite catalyst precursor is, for example, 50 mL / min or more, preferably 100 mL / min or more, and for example, 1000 mL / min or less, preferably 800 mL / min or less.

[0170] The volume percentage of hydrogen in the total volume of hydrogen and carbon monoxide is, for example, 30% by volume or more, preferably 50% by volume or more, more preferably 60% by volume or more, and also, for example, 95% by volume or less, preferably 85% by volume or less, more preferably 80% by volume or less.

[0171] The volume percentage of carbon monoxide in the total volume of hydrogen and carbon monoxide is, for example, 5% by volume or more, preferably 10% by volume or more, more preferably 20% by volume or more, and also, for example, 70% by volume or less, preferably 50% by volume or less, more preferably 40% by volume or less.

[0172] (CO treatment) In CO treatment, for example, a composite catalyst precursor is packed into a predetermined container and heated to the reduction temperature using a heater such as an electric tubular furnace, while a mixed gas of carbon monoxide and nitrogen is circulated through the container. In CO treatment, the above H ２ Unlike CO treatment, H is added to a mixed gas of carbon monoxide and nitrogen. ２ It does not contain [H]. Also, in CO treatment, other gases (H) are added to the mixed gas of carbon monoxide and nitrogen. ２ It may contain (excluding) other gases. Preferably, it does not contain any gases other than carbon monoxide and nitrogen.

[0173] The reduction temperature is, for example, 200°C or higher, preferably 250°C or higher, and also, for example, 650°C or lower, preferably 450°C or lower. The reduction time is, for example, 2 hours or more, preferably 3 hours or more, and also, for example, 10 hours or less, preferably 5 hours or less.

[0174] The flow rate of the mixed gas of carbon monoxide and nitrogen per gram of composite catalyst precursor is, for example, 50 mL / min or more, preferably 100 mL / min or more, and for example, 1000 mL / min or less, preferably 800 mL / min or less.

[0175] The volume percentage of carbon monoxide in the total volume of carbon monoxide and nitrogen is, for example, 1 vol% or more, preferably 3 vol% or more, more preferably 5 vol% or more, and for example, 50 vol% or less, preferably 30 vol% or less, more preferably 20 vol% or less.

[0176] Through one of the above pretreatments, the active metal supported on the stabilized zirconia support in the solid oxide catalyst precursor is reduced from its metal oxide state to a state in which it is active in the reaction.

[0177] Furthermore, the stabilizing elements and active metals dissolved in the stabilized zirconia support are coated with the active metal in its metallic state supported on the stabilized zirconia support, and therefore are not reduced in this reduction process, maintaining their metal oxide state.

[0178] After the above pretreatment steps, air and / or nitrogen gas are circulated as needed.

[0179] As described above, composite catalysts can be manufactured.

[0180] 3. Method for Producing Hydrocarbons Next, an embodiment of a method for producing hydrocarbons using the composite catalyst described above will be explained. Specifically, this is a method for producing short-chain paraffins having 3 to 20 carbon atoms using the composite catalyst described above.

[0181] For example, a method for producing short-chain paraffins is CO and / or CO ２ A raw material gas containing hydrogen is brought into contact with the composite catalyst described above, and the main product is a short-chain paraffin having 3 to 20 carbon atoms, and the by-product is H ２ The reaction step includes obtaining a reaction product containing O. The reaction product may also contain paraffins other than short-chain paraffins having 3 to 20 carbon atoms, and olefins.

[0182] Specifically, CO ２ A raw material gas containing hydrogen is brought into contact with the composite catalyst described above, and the main product is a short-chain paraffin having 3 to 20 carbon atoms, and the by-product is H ２ A reaction product is obtained that contains oxygen (O) and CO, a typical residual intermediate product.

[0183] The reaction temperature is, for example, 100°C or higher, preferably 150°C or higher, and for example, 500°C or lower, preferably 450°C or lower.

[0184] The reaction pressure is, for example, 0.3 MPaG or higher, preferably 0.5 MPaG or higher, and for example, 3.0 MPaG or lower, preferably 1.0 MPaG or lower.

[0185] The raw material gas is CO ２ And if it contains hydrogen, CO ２ The volume ratio of CO2 to hydrogen (volume of hydrogen: CO2) ２ The volume of the two components is not particularly limited, for example, it can range from 2:1 to 10:1, or even from 3:1 to 6:1.

[0186] Furthermore, the gas flow rate per unit catalyst weight is, for example, 0.010 mol / NL·g-cat. or more, preferably 0.030 mol / NL·g-cat. or more, and also, for example, 1.000 mol / NL·g-cat. or less, preferably 0.500 mol / NL·g-cat. or less.

[0187] Thus, when the composite catalyst is brought into contact with the above-mentioned raw material gas, even if the stabilized zirconia support in the solid oxide catalyst contained in the composite catalyst supports an active metal in a metal oxide state, the metal oxide is maintained in a state that is predominantly reactive due to the hydrogen in the mixed gas.

[0188] Furthermore, in the solid oxide catalyst contained in the composite catalyst, the oxygen vacancies of the stabilized zirconia support are CO ２ CO attracts oxygen atoms, and the active metal in the metallic state supported on the stabilized zirconia carrier attracts hydrogen to form dissociated hydrogen, ２ Hydrogen reacts efficiently with hydrocarbons and byproducts H ２A reaction product containing O is generated. CO is mainly attracted to the active metal supported on the stabilized zirconia support, but the alkali metal in the active metal strengthens the alkalinity of the active metal, strongly attracting the C element in CO to the active metal, weakening the bond between C and O, and thus accepting the reaction from hydrogen to form a hydrocarbon. As described above, the synthesis rate of short-chain paraffins with 3 to 20 carbon atoms can be improved from hydrocarbons formed on the solid oxide catalyst by the zeolite contained in the composite catalyst. In other words, it is possible to improve the synthesis rate of hydrocarbons with 3 to 20 carbon atoms and to suppress the excessively high ratio of olefins to paraffins in hydrocarbons.

[0189] Furthermore, the metallic active metals supported on the surface of the solid oxide catalyst contained in the composite catalyst may detach from the surface of the solid oxide catalyst due to the supply of the raw material gas. In this case, the active metal ions dissolved in the stabilized zirconia support exposed from the detached portion are reduced to a metallic state and act as catalytic active sites.

[0190] In composite catalysts, by changing the formulation, pretreatment conditions, etc., CO ２ The conversion rate can be adjusted, and furthermore, the proportion of each short-chain paraffin in the short-chain paraffins with 3 to 20 carbon atoms can also be adjusted.

[0191] CO ２ The conversion rate is, for example, 20% or more, preferably 30% or more, and more preferably 40% or more.

[0192] The ratio of CO (C-mol%) to the total amount of CO and hydrocarbons is, for example, 40 C-mol% or less, preferably 35 C-mol% or less, more preferably 30 C-mol% or less, and even more preferably 25 C-mol% or less.

[0193] Note that C-mol indicates the number of moles of carbon. Furthermore, hydrocarbons refer to short-chain paraffins with 3 to 20 carbon atoms (the main product), paraffins other than short-chain paraffins with 3 to 20 carbon atoms, and olefins.

[0194] If the proportion of CO (C-mol%) to the total amount of CO and hydrocarbons is less than or equal to the above upper limit, then CO ２ By efficiently reacting it with hydrogen, hydrocarbons can be obtained.

[0195] The ratio of methane (a paraffin with 1 carbon atom) to the total amount of CO and hydrocarbons (C-mol%) is, for example, 35 C-mol% or less, preferably 30 C-mol% or less, and more preferably 25 C-mol% or less.

[0196] If the proportion of methane (C-mol%) to the total amount of CO and hydrocarbons is below the above upper limit, the rate of methane production can be relatively suppressed.

[0197] The ratio (C-mol%) of the total amount of short-chain paraffins (propane and butane) having 3 and 4 carbon atoms to the total amount of CO and hydrocarbons is, for example, 3.0 C-mol% or more, preferably 5.0 C-mol% or more, more preferably 6.0 C-mol% or more, and even more preferably 7.0 C-mol% or more. Alternatively, the ratio (C-mol%) of the total amount of short-chain paraffins (propane and butane) having 3 and 4 carbon atoms to the total amount of CO and hydrocarbons may be, for example, 20 C-mol% or more, preferably 25 C-mol% or more, and more preferably 30 C-mol% or more.

[0198] The ratio (C-mol%) of the total amount of short-chain paraffins having 5 to 20 carbon atoms to the total amount of CO and hydrocarbons is, for example, 6.0 C-mol% or more, preferably 8.0 C-mol% or more, more preferably 10 C-mol% or more, and even more preferably 12 C-mol% or more. Alternatively, the ratio (C-mol%) of the total amount of short-chain paraffins having 5 to 20 carbon atoms to the total amount of CO and hydrocarbons may be, for example, 15 C-mol% or more, preferably 20 C-mol% or more, and more preferably 25 C-mol% or more.

[0199] The ratio (C-mol%) of the total amount of short-chain paraffins having 3 to 20 carbon atoms to the total amount of CO and hydrocarbons is, for example, 10 C-mol% or more, preferably 15 C-mol% or more, more preferably 18 C-mol% or more, and even more preferably 20 C-mol% or more. Alternatively, the ratio (C-mol%) of the total amount of short-chain paraffins having 3 to 20 carbon atoms to the total amount of CO and hydrocarbons may be, for example, 30 C-mol% or more, preferably 35 C-mol% or more, and more preferably 40 C-mol% or more.

[0200] The ratio of the total amount of C3 and C4 hydrocarbons to the total amount of CO and hydrocarbons (C-mol%) is, for example, 10 C-mol% or more, preferably 15 C-mol% or more, and more preferably 18 C-mol% or more.

[0201] The ratio of the total amount of hydrocarbons having 5 to 20 carbon atoms (C-mol%) to the total amount of CO and hydrocarbons is, for example, 5.0 C-mol% or more, preferably 8.0 C-mol% or more, and more preferably 10 C-mol% or more.

[0202] In the resulting hydrocarbon, the ratio of olefin to paraffin is, for example, 5.0 or less, preferably 3.0 or less, and more preferably 2.0 or less. In the resulting hydrocarbon, the ratio of olefin to paraffin may also be, for example, 1.0 or less, preferably 0.5 or less, and more preferably 0.3 or less.

[0203] CO ２ The conversion rate, the respective percentages (C-mol%) of CO and hydrocarbons to the total sum, and the ratio of olefins to paraffin can be measured by the method described in the examples below. ２The conversion rate, the respective percentages (C-mol%) of CO and hydrocarbons to the total sum, and the ratio of olefins to paraffin can be adjusted by the amount of composite catalyst and the composition of the supplied raw material gas. The ratio of olefins to paraffin is calculated using hydrocarbons with 2 to 4 carbon atoms. Even when calculating the ratio of olefins to paraffin using hydrocarbons with 2 to 4 carbon atoms, the performance of the composite catalyst in adding hydrogen to aliphatic unsaturated hydrocarbons (olefins) to produce aliphatic saturated hydrocarbons (paraffin) can be appropriately evaluated.

[0204] The method for producing short-chain paraffins may, after the above reaction step, optionally include a separation step using known separation methods (e.g., distillation and extraction). As an example of the separation step, H may be separated from the above reaction product. ２ A step to separate O, and from the above reaction products, unreacted gas (CO ２ and H ２ This includes a step of separating the gas (containing CO) and intermediate products (containing CO).

[0205] Furthermore, the method for producing short-chain paraffins may include a second reaction step with another catalyst. Examples of other catalysts include the methanation catalysts described in Japanese Patent Application Publication No. 2011-206770 and Japanese Patent Application Publication No. 2013-119526.

[0206] (Effects) The composite catalyst of the present invention comprises a stabilized zirconia support, a solid oxide catalyst supported on the stabilized zirconia support and comprising Fe and an alkali metal active metal, and a zeolite having one skeleton structure selected from the group consisting of MFI structure, MOR structure, CHA structure, FER structure, AEI structure, BEA structure, and FAU structure. Therefore, it is possible to improve the synthesis ratio of hydrocarbons having 3 to 20 carbon atoms and to suppress the olefin ratio to paraffin in the hydrocarbons from becoming excessively high.

[0207] The present invention will be further described below with reference to examples and comparative examples. However, the present invention is not limited in any way to the examples and comparative examples. Furthermore, specific numerical values ​​such as blending ratios (content ratios), physical properties, and parameters used in the following description may be replaced with the upper limits (numbers defined as "less than or equal to" or "less than") or lower limits (numbers defined as "greater than or equal to" or "greater than") of the corresponding blending ratios (content ratios), physical properties, and parameters described in the "Modes for Carrying Out the Invention" above.

[0208] Example 1 [Preparation of Solid Oxide Catalyst Precursor] 100 g of zirconia hydrosol "ZSL-10A" (manufactured by Daiichi Rare Elements Chemical Industry Co., Ltd., Zr: 10 mass percent, pH = 7.2) was weighed, and Fe nitrate (purity 99% or higher, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) and Y nitrate (purity 99% or higher, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were mixed according to the composition (atomic %) of the solid oxide catalyst shown in Table 1. The mixture of zirconia hydrosol and the nitrates of each raw material was mixed in a SiC crucible to obtain a homogeneous slurry. The slurry was placed in a muffle furnace and heated and dried at 170°C for 2 hours to produce a hard slurry by volatilizing the excess water. Furthermore, with the hard slurry still in the muffle furnace, the temperature of the muffle furnace was raised to 650°C at a rate of 20°C / min, and the hard slurry was calcined at 650°C for 4 hours. The grayish-black bulk oxide obtained after calcination was ground in a mortar and pestle, and then sieved through a sieve with a mesh size of 75 μm to obtain a solid oxide catalyst material.

[0209] Next, K nitrate (purity 99% or higher, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was dissolved in water in a vacuum-sealed container, and the above-mentioned solid oxide catalyst material was added to the solution and stirred to obtain a dispersion. After stirring, the mixture was vacuumed for 12 hours to expel any remaining air from the pores of the solid oxide catalyst material. After vacuuming, the mixture was transferred to a heat-resistant container and calcined at 550°C for 4 hours. The grayish-black bulk oxide obtained after calcination was ground in a mortar and pestle, and passed through a sieve with a mesh size of 75 μm to obtain a solid oxide catalyst precursor.

[0210] [Preparation of Zeolite] First, a seed crystal zeolite having a CHA structure was synthesized. Specifically, 8.09 g of an aqueous solution of N,N,N-trimethyl-1-adamantan ammonium hydroxide (TMadaOH aqueous solution) (product name: Zeogen™ 2825, solid content: 25% by mass, manufactured by SACHEM) as an organic structure-determining agent and 0.38 g of sodium hydroxide as an alkali metal source were added to a 50 ml beaker and stirred for 5 minutes. Next, 2.1 g of a zeolite having a first FAU structure (product name: HSZ-360, Si / Al ratio: 7, manufactured by Tosoh Corporation) and 0.9 g of a zeolite having a second FAU structure (product name: HSZ-390, Si / Al ratio: 200, manufactured by Tosoh Corporation) were added and stirred for 15 minutes to obtain a mixture. The molar composition of each substance in the mixture was TMadaOH / SiO ２ =0.2, NaOH / SiO ２ = 0.2, H ２ O / SiO ２ The values ​​were 7 and Si / Al = 10.

[0211] The above mixture was placed in a Teflon® inner cylinder of an autoclave and hydrothermally synthesized at 160°C for 40 hours. After hydrotherm synthesis, the autoclave was cooled, and the white solid that had settled in the Teflon® inner cylinder was recovered and washed with deionized water. A centrifuge was used for washing, and the mixture was washed multiple times until the supernatant liquid was nearly neutral. After washing, the white solid was dried overnight in a dryer at 110°C. The dried white solid was calcined at 550°C for 12 hours under air circulation to obtain a seed crystal zeolite having a CHA structure.

[0212] Next, a zeolite having a CHA structure was synthesized using the above-mentioned seed crystal zeolite having a CHA structure for use in the composite catalyst of Example 1. Specifically, 8.09 g of TMAdaOH aqueous solution as an organic structure-determining agent and 0.38 g of sodium hydroxide as an alkali metal source were added to a 50 ml beaker and stirred for 5 minutes. Then, 2.1 g of zeolite having a first FAU structure, 0.9 g of zeolite having a second FAU structure, and 0.3 g of the above-mentioned seed crystal zeolite having a CHA structure were added and stirred for 15 minutes.

[0213] The above mixture was placed in a Teflon® inner cylinder of an autoclave and hydrothermally synthesized at 160°C for 40 hours. After hydrothermally synthesized, the autoclave was cooled, and the white solid that had precipitated in the Teflon® inner cylinder was recovered and washed with deionized water. The supernatant was washed multiple times by centrifugation until it was nearly neutral. After washing, the white solid was dried overnight in a dryer at 110°C. The dried white solid was calcined at 550°C for 12 hours under air circulation to obtain a sodium-type zeolite having a CHA structure. Next, the obtained sodium-type zeolite having a CHA structure was ion-exchanged with a 1 M aqueous solution of ammonium nitrate at 80°C for 2 hours. Then, it was dried at 110°C and calcined at 550°C for 3 hours under air circulation to obtain a powdered proton-type zeolite having a CHA structure. Powdered proton-type zeolite with a CHA structure was pressurized at a pressure of 30 MPaG for 3 minutes in a pressure molding machine to solidify it into a disc shape. Then, the solidified disc-shaped proton-type zeolite with a CHA structure was lightly tapped with a rubber hammer to obtain random bulk proton-type zeolite with a CHA structure having a particle size of approximately 1.5 mm to 3.0 mm. This was sieved to obtain granular proton-type zeolite with a CHA structure having a particle size of 1.5 to 2.0 mm. The average primary particle size of the proton-type zeolite with a CHA structure was measured to be 300 nm by observation with a scanning electron microscope.

[0214] [Preparation of Composite Catalyst] A composite catalyst precursor was prepared by adding a proton-type zeolite having a CHA structure after classification to the solid oxide catalyst precursor described above, in the mass percentage (mass%) shown in Table 1, and mixing. Next, the composite catalyst precursor was pretreated. Specifically, a predetermined amount of 0.5 g of glass wool was laid in a 1 / 2 inch stainless steel tube, the composite catalyst precursor was packed on top of it, and the tube was surrounded by a tubular furnace. The furnace temperature was adjusted so that the temperature of the composite catalyst precursor packed in the tube was around 500°C. After the temperature reached around 500°C, hydrogen was continuously supplied from the top of the tube at a flow rate of 500 mL / min for 4 hours to activate the composite catalyst precursor (H ２(Processing). Next, the hydrogen supply was stopped, the temperature was lowered to approximately room temperature, nitrogen was flowed at a flow rate of 100 mL / min for 1 hour, and air was supplied from another port at a flow rate of 5 mL / min so that the air / nitrogen ratio was 1 / 20. The mixed gas of nitrogen and air was then continuously flowed at a total flow rate of 105 mL / min for 30 minutes. Furthermore, the air flow rate was increased to 10 mL / min, and the mixed gas was continuously flowed for 60 minutes. After that, the composite catalyst of Example 1 was removed from the tube.

[0215] Examples 2 to 13 and Comparative Examples 1 to 3: Based on Tables 1 and 2, composite catalysts for Examples 2 to 13 and Comparative Examples 1 to 3 were prepared in the same manner as in Example 1, except that at least one of the following was changed: the composition (atomic %) of the solid oxide catalyst, the type of zeolite, and the blending ratio of the zeolite.

[0216] In addition to those mentioned above, the raw materials used in Examples 2 to 13 and Comparative Examples 1 to 3 are listed below. The zeolites listed below can be used as seed crystal zeolites, and can also be used as zeolites constituting composite catalysts. The average primary particle size of the zeolites listed below was measured by observation using a scanning electron microscope. Co nitrate (purity 99% or higher, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) Ni nitrate (purity 99% or higher, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) Sm nitrate (purity 99% or higher, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) Ca nitrate (purity 99% or higher, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) Na nitrate (purity 99% or higher, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) Zeolite with FER structure (product name: HSZ-720K0D1C, manufactured by Tosoh Corporation, 1.5 mmφ pellet, average primary particle size 800 nm) Zeolite with MFI structure (product name: HSZ-822HOD1A, manufactured by Tosoh Corporation, 1.5 mmφ pellet, average primary particle size 350 nm) Zeolite with MOR structure (product name: HSZ-640HOD1A, manufactured by Tosoh Corporation, 1.5 mmφ pellet, average primary particle size 350 nm) Zeolite with BEA structure (product name: HSZ-931H0D1A, manufactured by Tosoh Corporation, 1.5 mmφ pellet, average primary particle size 500 nm)

[0217] In Examples 2, 4, 5, 7, and 8, the above-mentioned zeolites were used as zeolites constituting the composite catalyst, based on Tables 1 and 2.

[0218] In Comparative Example 3, only the solid oxide catalyst was prepared without mixing in zeolite. The pretreatment was also carried out using only the solid oxide catalyst precursor without mixing in zeolite.

[0219] Example 14 A composite catalyst of Example 14 was prepared in the same manner as in Example 1, except that the zeolite was prepared according to the following procedure.

[0220] [Preparation of Zeolite] Following the same procedure as in Example 1, a sodium-type zeolite having a CHA structure was prepared. Then, using an aqueous solution of ammonium acetate, the solution was replaced as needed and ion-substituted for two days to prepare an ammonium ion-type zeolite having a CHA structure. The obtained ammonium ion-type zeolite having a CHA structure (in powder form) was pressure-molded to produce a bulk ammonium ion-type zeolite having a CHA structure with a particle size of 1.5 to 2 mm. Next, Fe nitrate was dissolved in pure water to a metal salt concentration of 0.01 M to prepare an aqueous solution of Fe nitrate. Then, the bulk ammonium ion-type zeolite having a CHA structure was added to the aqueous solution of Fe nitrate so that the ratio of Fe supported on the zeolite to the zeolite (amount of Fe supported / mass of zeolite × 100) was 1.0% by mass, and the mixture was stirred at 80°C for 12 hours. After stirring, the solid components were recovered by centrifugation, and the recovered material was washed six times with deionized water. Subsequently, the material was dried at 100°C for 2 hours and then calcined at 550°C for 4 hours to obtain a proton-type zeolite having a CHA structure containing (supported) Fe. In Example 12, it is acceptable that some of the countercations (protons) of the Fe-supported proton-type zeolite having a CHA structure are substituted with Fe ions.

[0221] Examples 15-19: Based on Table 3, composite catalysts for Examples 15-19 were prepared in the same manner as in Example 14, except that at least one of the following was changed: the composition (atomic %) of the solid oxide catalyst, the type of zeolite, the blending ratio of the zeolite, and the contained metal (metal ion).

[0222] In addition to those mentioned above, the raw materials used in Examples 15 to 19 are listed below: Ca nitrate (purity 99% or higher, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) Zn nitrate (purity 99% or higher, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) Ammonium dihydrogen phosphate (purity 99% or higher, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) Co nitrate (purity 99% or higher, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)

[0223] In Example 19, a zeolite having the MFI structure described above (product name: HSZ-822HOD1A, manufactured by Tosoh Corporation) was used, and Co was supported on it using the same procedure as in Example 14.

[0224] Example 20 A composite catalyst of Example 20 was prepared in the same manner as in Example 1, except that the composite catalyst precursor was pretreated according to the following procedure.

[0225] A predetermined amount of 0.5 g of glass wool was packed into a 1 / 2 inch stainless steel tube, and a composite catalyst precursor was filled on top of it. The tube was then surrounded by a tubular furnace. The furnace temperature was adjusted so that the temperature of the composite catalyst precursor inside the tube was around 250°C. After the temperature reached around 250°C, a mixed gas consisting of hydrogen, carbon monoxide, and argon (volume of hydrogen:volume of carbon monoxide:volume of argon = 2:1:3) was continuously supplied from the top of the tube at a flow rate of 100 mL / min for 4 hours to activate the composite catalyst precursor (H ２(+CO treatment). Next, the supply of the mixed gas consisting of hydrogen, carbon monoxide, and argon was stopped, the temperature was lowered to approximately room temperature, nitrogen was flowed at a flow rate of 100 mL / min for 1 hour, and air was supplied from another port at a flow rate of 5 mL / min so that the air / nitrogen ratio was 1 / 20, and the mixed gas of nitrogen and air was continued to flow at a total flow rate of 105 mL / min for 30 minutes. Furthermore, the air flow rate was increased to 10 mL / min, and the mixed gas was continued to flow continuously for 60 minutes. After that, the composite catalyst of Example 20 was removed from the tube.

[0226] Examples 21-25: Based on Table 4, composite catalysts for Examples 21-25 were prepared in the same manner as in Example 18, except that at least one of the following was changed: the composition (atomic %) of the solid oxide catalyst, the type of zeolite, and the zeolite blending ratio.

[0227] In Examples 22 to 25, the zeolite having the above-mentioned CHA structure, the zeolite having the above-mentioned MFI structure (product name: HSZ-822HOD1A, manufactured by Tosoh Corporation), and the zeolite having the MOR structure were used in the proportions shown in Table 4.

[0228] Example 26: The composite catalyst of Example 26 was prepared in the same manner as in Example 1, except that the composite catalyst precursor was pretreated according to the following procedure.

[0229] A predetermined amount of 0.5 g of glass wool was packed into a 1 / 2 inch stainless steel tube, and a composite catalyst precursor was filled on top of it. The tube was then surrounded by a tubular furnace. The furnace temperature was adjusted so that the temperature of the composite catalyst precursor inside the tube was around 350°C. After the temperature reached around 350°C, a mixture of nitrogen and carbon monoxide (nitrogen volume:carbon monoxide volume = 9:1) was continuously supplied from the top of the tube at a flow rate of 100 mL / min for 4 hours to activate the composite catalyst precursor (CO treatment). Next, the supply of the nitrogen and carbon monoxide mixture was stopped, the temperature was lowered to approximately room temperature, nitrogen was flowed at a flow rate of 100 mL / min for 1 hour, and air was supplied from another port at a flow rate of 5 mL / min so that the air / nitrogen ratio was 1 / 20. The nitrogen and air mixture was then continuously flowed at a total flow rate of 105 mL / min for 30 minutes. Furthermore, the airflow rate was increased to 10 mL / min, and the mixed gas was continuously flowed for 60 minutes. After that, the composite catalyst of Example 26 was removed from the tube.

[0230] Example 27 A composite catalyst for Example 27 was prepared in the same manner as in Example 26, except that the composition (atomic %) of the solid oxide catalyst and the blending ratio of the zeolite were changed based on Table 4.

[0231] In Example 28, the composite catalyst of Example 28 was prepared in the same manner as in Example 4, except that the calcination temperature of the hard slurry was set to 900°C and the calcination time to 4 hours in the preparation of the solid oxide catalyst precursor.

[0232] Examples 29-32 and Comparative Example 4: Based on Table 5, composite catalysts for Examples 29-32 and Comparative Example 4 were prepared in the same manner as in Example 28, except that the type of zeolite was changed.

[0233] In addition to those mentioned above, the raw materials used in Examples 29 to 32 and Comparative Example 4 are listed below. Zeolite having a FAU structure (Y-type) (product name: CBV720, manufactured by ZEOLYST INTERNATIONAL, in powder form, average primary particle diameter 500 nm) Zeolite having an MFI structure (product name: CBV28014, manufactured by ZEOLYST INTERNATIONAL, in powder form, average primary particle diameter 950 nm) Zeolite having a BEA structure (product name: HSZ-941NOA, manufactured by Tosoh Corporation, in powder form, average primary particle diameter 700 nm) Zeolite having an LTA structure (product name: A-3 #100, manufactured by Tosoh Corporation, in powder form, average primary particle diameter 3000 nm)

[0234] In Example 29, a zeolite having an MOR structure (product name: HSZ-640HOD1A, manufactured by Tosoh Corporation) was used as the zeolite constituting the composite catalyst.

[0235] In Examples 30-32 and Comparative Example 4, based on Table 5, the powdered zeolite shown above was first compressed in a pressure molding machine at a pressure of 30 MPaG for 3 minutes to solidify into a disc shape. Then, the solidified disc-shaped zeolite was lightly tapped with a rubber hammer to obtain random bulk zeolite with a particle size of approximately 1.5 mm to 3.0 mm. This was then sieved to obtain granular zeolite with a particle size of 1.5 to 2.0 mm. Note that Example 31 used zeolite with an MFI structure (product name: CBV28014, manufactured by ZEOLYST INTERNATIONAL), which has a different Si / Al ratio from zeolite with an MFI structure (product name: HSZ-822HOD1A, manufactured by Tosoh Corporation).

[0236] <Evaluation> [Hydroxide Production] A small reactor, 10 cm in length and made from a 3 / 8-inch tube, was lined with 0.5 g of glass wool at the bottom of the tube, and 6 g of composite catalyst for each example and comparative example was gently packed on top of it. A tubular furnace was placed around the reactor, and the reactor was heated until the catalyst temperature reached 350°C. After reaching the predetermined temperature, the raw material gas (a mixture of hydrogen, carbon dioxide, and nitrogen; volume of hydrogen: volume of carbon dioxide: volume of nitrogen = 76:19:5) was supplied at 200 NL / min. The pressure at the reactor inlet was adjusted to 0.75 MPaG, and the gas flow rate per unit catalyst weight was 0.089 mol / NL·g-cat. From 90 minutes after the start of the reaction, the gas at the reactor outlet was sampled, and the data was read at 5 hours (Time On Stream = 5 Hr) when the product distribution had stabilized. The concentration of the product was analyzed using a 4-channel TCD gas chromatograph (product name: Agilent Micro GC990, manufactured by Agilent) and a 1-channel FID gas chromatograph (product name: Shimadzu GC-2014, manufactured by Shimadzu Corporation). The 4-channel TCD gas chromatograph showed the proportion of CO and hydrocarbons of each carbon number (C-mol%) to the total amount of CO and hydrocarbons in the gas at the reactor outlet (as shown in Tables 1-5), and the CO before and after the reaction. ２ The conversion rate was measured. The conversion rate was calculated based on the following formula. In addition, a single-channel FID gas chromatograph was used for the purpose of quantitative analysis of isomers and hydrocarbons with 5 or more carbon atoms, and the ratio of olefins to paraffins (olefin / paraffin) in the gas at the reactor outlet, as shown in Tables 1 to 5, was measured. The ratio of olefins to paraffins (olefin / paraffin) was calculated using hydrocarbons with 2 to 4 carbon atoms. In Tables 1 to 5, the proportion of CO and hydrocarbons with each carbon number is listed as the selectivity of CO and hydrocarbons with each carbon number. In Tables 1 to 5, a high selectivity for hydrocarbons with 3 to 20 carbon atoms and a low olefin / paraffin ratio indicate a relatively high synthesis rate of short-chain paraffins with 3 to 20 carbon atoms.

[0237] CO ２Conversion rate (%) = (Supplied CO2 ２ Volume of CO2 - Residual CO2 after the reaction ２ (Volume of CO2) / Supplied CO2 ２ Volume × 100

[0238]

[0239]

[0240]

[0241]

[0242]

[0243] The above invention is provided as an illustrative embodiment of the present invention, but this is merely illustrative and should not be interpreted restrictively. Modifications of the present invention that are obvious to those skilled in the art are included in the claims below.

[0244] The composite catalyst of the present invention is suitably used to produce short-chain paraffins having 3 to 20 carbon atoms, which are the main components of liquefied petroleum gas, industrial fuels, and fuels for mobile vehicles.

Claims

A composite catalyst comprising a solid oxide catalyst and a zeolite, The solid oxide catalyst comprises a stabilized zirconia support and an active metal supported on the stabilized zirconia support. The stabilized zirconia support has a tetragonal and / or cubic crystal structure in which the stabilizing element is solid-dissolved in zirconia. The activated metal includes Fe and alkali metals. The composite catalyst comprises at least one zeolite having a skeletal structure selected from the group consisting of MFI structure, MOR structure, CHA structure, FER structure, AEI structure, BEA structure, and FAU structure. 　 The composite catalyst according to claim 1, wherein the active metals consist of Fe and K. 　 The composite catalyst according to claim 1, wherein the active metal comprises Fe, Co, and K. 　 The composite catalyst according to claim 1, wherein the stabilizing element is at least one element selected from the group consisting of Y, Sm, Ca, Ce, La, Pr, Nd, Gd, Dy, and Mg. 　 The composite catalyst according to claim 4, wherein the stabilizing element is Y. 　 The composite catalyst according to claim 1, wherein, in atomic percent based on the elemental state of the metal, the atomic ratio of the total Fe and alkali metal to the sum of Zr constituting the stabilized zirconia support and the stabilizing element and the active metal (= (Fe + alkali metal) / (Zr + stabilizing element + active metal) × 100) is 55 atomic percent or more and 95 atomic percent or less. 　 The composite catalyst according to claim 1, wherein the content ratio of the zeolite in the composite catalyst is 50% by mass or more and 75% by mass or less. 　 The composite catalyst according to any one of claims 1 to 7, wherein the zeolite is a proton-type zeolite containing a proton as a countercation. 　 The composite catalyst according to any one of claims 1 to 7, wherein the zeolite is a metal ion type zeolite containing at least one metal ion selected from the group consisting of Fe, Co, Ni, Mg, Ca, Cu, Zn, and Cr as a counter cation. The composite catalyst according to any one of claims 1 to 7, wherein at least one selected from the group consisting of Fe, Co, Ni, P, Mo, Mn, and Ca is supported on the zeolite. 　 The composite catalyst according to any one of claims 1 to 7, wherein the average primary particle size of the zeolite is 1000 nm or less. 　 The composite catalyst according to any one of claims 1 to 7, wherein the zeolite comprises at least one zeolite having a skeletal structure selected from the group consisting of an MFI structure, a MOR structure, a CHA structure, a FER structure, and an AEI structure. 　 The composite catalyst according to claim 12, wherein the zeolite comprises at least one zeolite having a skeletal structure selected from the group consisting of a CHA structure and an AEI structure. 　 The composite catalyst according to claim 12, wherein the zeolite is a zeolite having a CHA structure.

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