CO2 recovery composition, hydrocarbon production catalyst, and hydrocarbon production system

Abstract

The present invention aims to provide a CO2 recovery composition with improved CO2 recovery performance, a hydrocarbon production catalyst utilizing the composition, and a hydrocarbon production system utilizing the catalyst. [Solution] The present invention relates to a CO2 recovery composition comprising Al, one or more elements selected from alkali metal elements (hereinafter referred to as "Group 1 elements"), and one or more elements selected from Co, Ni, Rh, Pd, and Pt (hereinafter referred to as "Group 2 elements"), wherein the following formula (1): 1.5 ≤ R1 / R2 ≤ 6 ···(1) [In the formula, R1 represents the ratio of the oxide-equivalent mass of the first group element in the composition to the sum of the oxide-equivalent mass of the first group element and the metallic-equivalent mass of the second group element, and R2 represents the ratio of the metallic-equivalent mass of the second group element in the composition to the sum of the oxide-equivalent mass of the first group element and the metallic-equivalent mass of the second group element.] The present invention provides the composition that satisfies the requirements.

Description

[Technical Field]

[0001] This invention relates to a CO2 recovery composition, a hydrocarbon production catalyst, and a hydrocarbon production system. [Background technology]

[0002] When exhaust gases containing CO2 are released into the atmosphere, they cause global warming. Furthermore, the accumulation of CO2 from human breath in enclosed spaces such as spacecraft and space stations is harmful to human health. Therefore, technologies for capturing CO2 and converting it into other substances are being researched. One such technology involves capturing CO2 and reacting it with H2 to convert it into methane (for example, Patent Documents 1-3). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2019-108290 [Patent Document 2] Japanese Patent Publication No. 2019-188353 [Patent Document 3] Japanese Patent Publication No. 2022-022908 [Overview of the project] [Problems that the invention aims to solve]

[0004] However, conventional compositions used for CO2 capture had room for improvement in terms of CO2 capture performance.

[0005] Therefore, the present invention aims to provide a CO2 recovery composition with improved CO2 recovery performance, a hydrocarbon production catalyst utilizing the composition, and a hydrocarbon production system utilizing the catalyst. [Means for solving the problem]

[0006] To solve the above problems, the present invention provides the following compositions, catalysts, and systems. [1] A CO2 recovery composition comprising Al, one or more elements selected from alkali metal elements (hereinafter referred to as "Group 1 elements"), and one or more elements selected from Co, Ni, Rh, Pd, and Pt (hereinafter referred to as "Group 2 elements"), Formula (1): 1.5 ≤ R1 / R2 ≤ 6 ···(1) [In the formula, R1 represents the ratio of the oxide-equivalent mass of the first group element in the composition to the sum of the oxide-equivalent mass of the first group element and the metallic-equivalent mass of the second group element, and R2 represents the ratio of the metallic-equivalent mass of the second group element in the composition to the sum of the oxide-equivalent mass of the first group element and the metallic-equivalent mass of the second group element.] The composition that satisfies the requirements. [2] The composition according to [1], wherein R1 is 0.2 or more and 0.86 or less. [3] The composition is of the following formula (2): 1 ≤ R³ ···(2) [In the formula, R3 represents the ratio of the mass of A1 in Al2O3 terms to the sum of the mass of the first group element in oxide terms and the mass of the second group element in metallic terms in the composition.] A composition according to [1] or [2] that satisfies the following conditions. [4] The composition according to any one of [1] to [3], wherein the element of group 1 is composed of one or more elements selected from Na and K. [5] The composition according to any one of [1] to [4], wherein the second group element is composed of one or more elements selected from Pt and Co. [6] The composition according to any one of [1] to [5], wherein the first group element is composed of Na and the second group element is composed of Pt, or the first group element is composed of K and the second group element is composed of Co. [7] The composition according to [6], wherein the first group element is composed of Na and the second group element is composed of Pt. [8] The composition according to any one of [1] to [7], wherein the composition contains an Al-based oxide, and at least a part of the elements of the first group and at least a part of the elements of the second group are supported on the Al-based oxide. [9] A catalyst for producing hydrocarbons, comprising a first composition and a second composition, wherein the first composition contains the composition according to any one of [1] to [8], and the second composition contains Ce and one or more elements (hereinafter referred to as "the third group of elements") having an action of reducing CO2 and / or CO to produce hydrocarbons.

[10] The catalyst according to [9], wherein the third group of elements is composed of one or more elements selected from Ni and Ru.

[11] The catalyst according to

[10] , wherein the third group of elements is composed of Ni.

[12] The catalyst according to any one of [9] to

[11] , wherein the second composition contains a Ce-based oxide, and at least a part of the third group of elements is supported on the Ce-based oxide.

[13] The catalyst includes a substrate having a first substrate part and a second substrate part, a first catalyst layer provided on the first substrate part, and a second catalyst layer provided on the second substrate part. The first catalyst layer contains the first composition. The catalyst according to any one of [9] to

[12] , wherein the second catalyst layer contains the second composition.

[14] A hydrocarbon production system, comprising a reaction chamber and the catalyst according to any one of [9] to

[13] accommodated in the reaction chamber. [Effects of the Invention]

[0007] According to the present invention, there are provided a composition for CO2 recovery with improved CO2 recovery performance, a catalyst for hydrocarbon production using the composition, and a hydrocarbon production system using the catalyst. [Brief Description of the Drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram of a hydrocarbon production system according to an embodiment of the present invention. [Figure 2] Figure 2 is an end view of the hydrocarbon production catalyst according to the first embodiment (end view taken along line A-A in Figure 1). [Figure 3] Figure 3 is an end view of the hydrocarbon production catalyst according to the first embodiment (end view taken along line B-B in Figure 1). [Figure 4] Figure 4 is an enlarged view of the region indicated by reference numeral R1 in Figure 2. [Figure 5] Figure 5 is an enlarged view of the region indicated by reference numeral R2 in Figure 3. [Figure 6] Figure 6 is an end view of the hydrocarbon production catalyst according to the first embodiment (end view taken along line C-C in Figure 1). [Figure 7] Figure 7 is an end view of the hydrocarbon production catalyst according to the second embodiment (end view corresponding to Figure 6).

MODE FOR CARRYING OUT THE INVENTION

[0009] ≪Explanation of Terms≫ Hereinafter, the terms used in this specification will be explained. The following explanations apply throughout this specification unless otherwise specified.

[0010] <Metal Element> The term "metal element" includes semi-metal elements such as Si and B.

[0011] <Rare Earth Element> The term "rare earth element" includes Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu.

[0012] <Noble Metal Element> The term "noble metal element" includes Pt, Pd, Rh, Ru, Os, Ir, Au, and Ag.

[0013] <Oxide> The meaning of the term "oxide" is as follows: Oxides of rare earth elements other than Ce, Pr, and Tb are sesquioxides (M2O3, where M represents rare earth elements other than Ce, Pr, and Tb), oxides of Ce are CeO2, and oxides of Pr are Pr6O 11 This means that Tb oxide is Tb4O7, Al oxide is Al2O3, Zr oxide is ZrO2, Si oxide is SiO2, B oxide is B2O3, Cr oxide is Cr2O3, Mg oxide is MgO, Ca oxide is CaO, Sr oxide is SrO, Ba oxide is BaO, Fe oxide is Fe3O4, Mn oxide is Mn3O4, Ti oxide is TiO2, Zn oxide is ZnO, Sn oxide is SnO2, Li oxide is Li2O, Na oxide is Na2O, K oxide is K2O, Rb oxide is Rb2O, and Cs oxide is Cs2O.

[0014] <Mass of metallic elements in terms of oxide equivalent> The term "mass of a metallic element in terms of its oxide equivalent" refers to the mass of a metallic element calculated by assuming that the metallic element exists as an oxide of that metallic element. The meaning of "oxide" of a metallic element is as described above.

[0015] <Mass equivalent of metallic elements in metallic form> The term "metallic equivalent mass of a metallic element" refers to the mass of a metal calculated by assuming that the metallic element exists as a metal composed of that metallic element.

[0016] ≪Composition for CO2 Capture≫ The CO2 capture composition (hereinafter referred to as "this composition") will be described below.

[0017] This composition contains Al, elements from group 1, and elements from group 2.

[0018] Al exists in this composition in the form of an Al-containing oxide. On the surface of the Al-containing oxide, there are hydroxyl groups (i.e., Al-OH) bonded to Al. These hydroxyl groups bonded to Al may be generated, for example, by the reaction of the Al-containing oxide with moisture in the atmosphere, or by performing a reduction treatment on this composition before use.

[0019] Al-containing oxides are usually in particulate form. Examples of Al-containing oxides include Al-based oxides and alumina binders. From the viewpoint of improving the heat resistance of this composition, it is preferable that at least a portion of the Al is present in the composition in the form of an Al-based oxide.

[0020] Al-based oxides are distinguished from alumina (alumina binder), which is used as a binder, by having particle sizes suitable for use as carriers for Group 1 and Group 2 elements. From the viewpoint of improving support properties, Al-based oxides are preferably porous.

[0021] The average particle size of the Al-based oxide is preferably 2 μm to 200 μm, more preferably 3 μm to 180 μm, and even more preferably 4 μm to 150 μm. The method for measuring the average particle size of the Al-based oxide is as follows: A sample obtained from this composition is observed using a scanning electron microscope, and the directional diameter (Ferret diameter) of 100 Al-based oxides arbitrarily selected from the field of view is measured, and the average value is taken as the average particle size of the Al-based oxide.

[0022] Al-based oxides may contain one or more metallic elements other than Al (hereinafter referred to as "additional element M1"). Additional element M1 can be selected from, for example, rare earth elements (e.g., Ce, Y, Pr, La, Nd, Sm, Eu, Gd, etc.), alkaline earth metal elements (e.g., Mg, Ca, Sr, Ba, etc.), B, Si, Zr, Cr, etc.

[0023] In Al-based oxides, the additional element M1 may form a solid solution phase (for example, a solid solution phase of Al2O3 and an oxide of the additional element M1), a single phase which is either a crystalline or amorphous phase (for example, an oxide phase of the additional element M1), or both a solid solution phase and a single phase. However, it is preferable that at least a portion of the additional element M1 forms a solid solution phase.

[0024] Examples of Al-based oxides include alumina (Al2O3), oxides obtained by modifying the surface of alumina with an additional element M1, and oxides obtained by solid-solving the additional element M1 in alumina. Examples of Al-based oxides containing the additional element M1 include alumina-silica, alumina-zirconia, alumina-chromia, alumina-ceria, and alumina-lantana.

[0025] The Al-based oxide may be an Al-based oxide in which the metal element with the highest mass content among the metal elements constituting the Al-based oxide is Al (hereinafter referred to as the "first Al-based oxide"), or an Al-based oxide in which the metal element with the highest mass content among the metal elements constituting the Al-based oxide is a metal element other than Al (hereinafter referred to as the "second Al-based oxide"), or a mixture of the first and second Al-based oxides.

[0026] From the viewpoint of improving the heat resistance of this composition, the percentage of the mass of the first Al-based oxide relative to the total mass of all Al-based oxides in this composition (hereinafter referred to as "percentage P1") is preferably 80% by mass or more, more preferably 85% by mass or more, and even more preferably 90% by mass or more. The upper limit may be 100% by mass or less than 100% by mass.

[0027] If information on the raw materials used in the manufacture of this composition is known, the percentage P1 can be determined from the raw material information.

[0028] If information on the raw materials used in the manufacture of this composition is not available, the percentage P1 is determined by conventional methods such as scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX). Specifically, it is as follows:

[0029] [Method 1] (1) Elemental mapping is performed on the sample obtained from this composition using a conventional method such as SEM-EDX to identify the types of particles contained in the sample (e.g., first Al oxide, second Al oxide, etc.). (2) For each type of particle, several (e.g., 50) arbitrarily selected particles are subjected to elemental analysis using SEM-EDX to identify the constituent elements of the particles and determine the content (mass%) of each identified metal element in terms of oxides. For each type of particle, the average value of the content (mass%) of each metal element in terms of oxides is calculated from the analysis results of several (e.g., 50) particles, and this calculated average value is taken as the content (mass%) of each metal element in terms of oxides in each type of particle. (3) The sample obtained from this composition is subjected to elemental analysis using a conventional method such as SEM-EDX to identify the types of constituent elements of the entire sample. Of the identified metal elements, the content (mass%) of each metal element in the sample, on an oxide basis, is determined for the metal elements identified in (2) above. (4) The content of each type of particle in the sample is determined by creating and solving an equation that expresses the relationship between the content (mass%) of each metal element in the sample on an oxide basis, the content (mass%) of each metal element in each type of particle on an oxide basis, and the content (mass%) of each type of particle in the sample.

[0030] From the content (mass%) of each type of particle in the sample obtained by Method 1 described above, the percentage (mass%) of the mass of the first Al-based oxide relative to the total mass of all Al-based oxides in the sample is determined and defined as percentage P1 (mass%).

[0031] From the viewpoint of improving the heat resistance of this composition, the Al content in the first Al-based oxide, calculated as Al2O3 (hereinafter referred to as "content C1"), is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more, based on the mass of the first Al-based oxide. The upper limit may be 100% by mass or less than 100% by mass.

[0032] The content C1 is calculated using the formula: (mass of Al in the first Al-based oxide converted to Al2O3) / (mass of the first Al-based oxide) × 100. The "mass of the first Al-based oxide" refers to the total mass of the oxides of the metal elements, assuming that each metal element in the first Al-based oxide exists as an oxide. The meaning of "oxide" of a metal element is as described above.

[0033] If the composition of the first Al-based oxide is known, the content C1 can be determined from the composition of the first Al-based oxide.

[0034] If the composition of the first Al-based oxide is unknown, the content C1 is determined from elemental mapping obtained by energy-dispersive X-ray spectroscopy (EDX) analysis of a sample containing the first Al-based oxide, and from EDX elemental analysis of the specified first Al-based oxide. Specifically, the first Al-based oxide and other particles are qualitatively identified (color-coded) by elemental mapping, and the content C1 for the specified first Al-based oxide is determined by compositional analysis (elemental analysis) of the specified first Al-based oxide.

[0035] Group 1 elements consist of one or more elements selected from alkali metal elements. Alkali metal elements include Li, Na, K, Rb, and Cs. Group 1 elements may consist of one element or two or more elements.

[0036] The first group elements are present in the composition in the form of active components capable of exerting the effects described later, for example, in one or more forms selected from oxides, carbonates, and bicarbonates. From the viewpoint of more effectively exerting the effects described later, it is preferable that the first group elements are present in the composition in one or two forms selected from oxides and carbonates. The active components are, for example, in particulate form. The oxide of the first group element is M2O (wherein M represents the first group element), and the carbonate of the first group element is M2CO3 (wherein M represents the first group element).

[0037] The second group of elements consists of one or more elements selected from Co, Ni, Rh, Pd, and Pt. The second group of elements may consist of one element or two or more elements.

[0038] The second group elements are present in the composition in the form of active components capable of exerting the effects described later, for example, in one or more forms selected from metals, alloys, oxides, and carbonates. From the viewpoint of more effectively exerting the effects described later, it is preferable that the second group elements are present in the composition in one or two forms selected from metals and oxides. The active components are, for example, particulate. Co oxides are CoO or Co3O4, Ni oxides are NiO, Rh oxides are Rh2O3 or RhO2, Pd oxides are PdO, and Pt oxides are PtO2.

[0039] This composition is based on the following formula (1): 1.5 ≤ R1 / R2 ≤ 6 ···(1) It satisfies the condition.

[0040] In formula (1), R1 represents the ratio of the oxide-equivalent mass of the Group 1 elements in this composition to the sum of the oxide-equivalent mass of the Group 1 elements and the metallic-equivalent mass of the Group 2 elements, and R2 represents the ratio of the metallic-equivalent mass of the Group 2 elements in this composition to the sum of the oxide-equivalent mass of the Group 1 elements and the metallic-equivalent mass of the Group 2 elements. The methods for determining the oxide-equivalent mass of the Group 1 elements and the metallic-equivalent mass of the Group 2 elements will be described later.

[0041] "Oxide-equivalent mass of Group 1 elements" means the oxide-equivalent mass of a single element if Group 1 elements consist of only one element, and the total oxide-equivalent mass of two or more elements if Group 1 elements consist of two or more elements.

[0042] "Metallic mass of Group 2 elements" means the metallic mass of a single element if Group 2 elements consist of only one element, and the total metallic mass of two or more elements if Group 2 elements consist of two or more elements.

[0043] This composition can take the form of a powder, pellets, or the like.

[0044] This composition may contain components such as binders and stabilizers. Examples of binders include inorganic oxide binders such as alumina binder, ceria binder, zirconia binder, titania binder, and silica binder. Examples of stabilizers include nitrates, carbonates, oxides, and sulfates of alkaline earth metal elements (e.g., Sr, Ba, etc.).

[0045] This composition may be subjected to a reduction treatment before use. When this composition is subjected to a reduction treatment, the oxides of the Group 2 elements are reduced to a metallic state.

[0046] The performance of this composition will be described below.

[0047] When this composition comes into contact with CO2, it adsorbs the CO2. Therefore, this composition can be used to recover CO2. This composition contains Al, a first-group element, and a second-group element, and satisfies formula (1), thus having improved CO2 recovery performance. Note that "CO2 recovery performance" includes both CO2 adsorption performance and CO2 release performance. The reason why this composition has improved CO2 recovery performance will be explained below.

[0048] First-group elements are known to reversibly store CO2 in the form of carbonates. However, the use of first-group elements alone is not practical due to the high CO2 release initiation temperature (850°C). Therefore, in this composition, Al and first-group elements are used in combination. As a result, Al-OH present on the surface of the Al-containing oxide is converted to Al-OM (wherein M represents a first-group element), and the O element in Al-OM functions as a base site (CO2 adsorption site). The release of CO2 adsorbed at this base site starts at a significantly lower temperature than when first-group elements are used alone. Therefore, this composition can adsorb CO2 at the base site, and the release of CO2 adsorbed at the base site can start at a significantly lower temperature than when first-group elements are used alone. If the temperature at which CO2 release from this composition begins is denoted as "temperature T0", then temperature T0 is 400°C or lower. Temperature T0 is preferably 100°C to 400°C, more preferably 130°C to 350°C, and even more preferably 150°C to 300°C. If "temperature T1" is the temperature at which the release of CO2 from the composition is completed, then the difference between temperature T1 and temperature T0 (temperature T1 - temperature T0) is preferably 100°C to 500°C, more preferably 150°C to 450°C, and even more preferably 200°C to 400°C. Note that temperature T1 may change due to the amount of CO2 adsorbed by the composition, the heating rate of the composition, the pressure when the composition releases CO2, and the space velocity of the gas flowing through the reaction chamber containing the composition when the composition releases CO2. The space velocity of the gas is the gas flow rate (m³). 3 h ―1 ) the volume of the reaction chamber (m³ 3 It can be found by dividing by ).

[0049] Using only Al and Group 1 elements results in insufficient progress in the base site formation reaction, leading to insufficient CO2 adsorption. Therefore, in this composition, in addition to Al and Group 1 elements, Group 2 elements are also used. Group 2 elements have the effect of promoting the progress of the base site formation reaction. Consequently, the use of Group 2 elements can increase the amount of CO2 adsorbed.

[0050] If R1 / R2 is less than 1.5, the relative amount of Group 1 elements to Group 2 elements is too small, resulting in insufficient progress of the base site formation reaction. As a result, the amount of CO2 adsorbed is insufficient. If R1 / R2 exceeds 6, the relative amount of Group 1 elements to Group 2 elements is too large, making it easier for the amphoteric oxide containing Al and the basic oxide of Group 1 elements to undergo an aluminate formation reaction, which is a reaction separate from the base site formation reaction, resulting in insufficient progress of the base site formation reaction. As a result, the amount of CO2 adsorbed is insufficient. Therefore, in this composition, R1 / R2 is set to be between 1.5 and 6. This makes it possible to increase the amount of CO2 adsorbed.

[0051] Similar to the elements of Group 1, alkaline earth metal elements are known to reversibly store CO2 in the form of carbonates. However, because the CO2 release initiation temperature is high (900°C), the use of alkaline earth metal elements alone is not practical. When Al and alkaline earth metal elements are used together, Al-OH present on the surface of the Al-containing oxide is converted to Al-OM (wherein M represents the alkaline earth metal element). However, because the alkaline earth metal element has a valence of 2 and a high charge density, its electron-donating ability to the oxygen element is weak, and the oxygen element in Al-OM cannot adequately adsorb CO2. Therefore, even if an alkaline earth metal element is used in place of the elements of Group 1 in this composition, the desired effect cannot be obtained.

[0052] Preferred embodiments of this composition will be described below.

[0053] From the viewpoint of more effectively increasing the amount of CO2 adsorbed, it is preferable that the composition contains an Al-based oxide (particularly a first Al-based oxide), and that at least a portion of the elements of group 1 and at least a portion of the elements of group 2 are supported on the Al-based oxide (particularly the first Al-based oxide).

[0054] This composition may contain carriers other than Al-based oxides, and at least some of the elements from group 1 and at least some of the elements from group 2 may be supported on carriers other than Al-based oxides.

[0055] Other supports besides Al-based oxides can be selected from inorganic oxides. Examples of inorganic oxides include oxides of rare earth elements (e.g., CeO2), zirconia (ZrO2), silica (SiO2), titania (TiO2), zeolites (aluminosilicates), and oxides based on MgO, ZnO, SnO2, etc.

[0056] "At least a portion of an element is supported on a carrier" means that at least a portion of the element is physically or chemically adsorbed or held on the outer surface and / or the inner surface of the pores of the carrier. The fact that at least a portion of the element is supported on the carrier can be confirmed, for example, using SEM-EDX. Specifically, if at least a portion of the element and at least a portion of the carrier are in the same region in an elemental mapping obtained by SEM-EDX, it can be determined that at least a portion of the element is supported on the carrier.

[0057] From the viewpoint of more effectively increasing the amount of CO2 adsorbed, the percentage of the mass of the Group 1 elements supported on the Al oxide (hereinafter referred to as "percentage Q1") relative to the total mass of all Group 1 elements in terms of oxides is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more. The upper limit may be 100% by mass or less than 100% by mass.

[0058] The percentage Q1 is obtained from the formula: Q11 / Q12 [wherein Q11 represents the percentage (mass%) of the mass of the Group 1 elements supported on the Al oxide relative to the mass of the composition, and Q12 represents the percentage (mass%) of the total mass of all Group 1 elements relative to the mass of the composition, relative to the mass of the composition.]

[0059] The following explains how to find Q11.

[0060] Q11 can be found using the following formula. Q11 = Al-based oxide content in this composition (mass%) × ratio A

[0061] The method for determining the content (mass%) of Al-based oxides in this composition is as follows.

[0062] If information on the raw materials used in the manufacture of this composition is known, the content of Al-based oxides in this composition can be determined from the raw material information. Specifically, the content of Al-based oxides in this composition can be determined from the following formula. The content of Al-based oxides in this composition = (mass of Al-based oxides) / (mass of this composition) × 100

[0063] If information on the raw materials used in the manufacture of this composition is not available, the Al-based oxide content in this composition can be determined by conventional methods such as SEM-EDX. Specifically, the Al-based oxide content (mass%) in the sample is determined by Method 1 described above, and this is taken as the Al-based oxide content in this composition.

[0064] The method for finding ratio A is as follows: (1) Elemental mapping is performed on the sample obtained from this composition using a conventional method such as SEM-EDX to identify the types of particles contained in the sample (e.g., Al-based oxides, non-Al-based carriers, etc.). (2) Multiple (e.g., 50) arbitrarily selected Al-based oxides, including the metal elements supported on the Al-based oxides (hereinafter referred to as "supported elements"), are subjected to elemental analysis using SEM-EDX to identify the constituent elements and supported elements of the Al-based oxides, and to determine the content (mass%) of each identified metal element in terms of oxide or metal. Specifically, for Al, the content (mass%) of Al in terms of Al2O3 is determined; for Group 1 elements, the content (mass%) of Group 1 elements in terms of oxide is determined; and for Group 2 elements, the content (mass%) of Group 2 elements in terms of metal is determined. If the constituent elements and supported elements of the Al-based oxides include other metal elements, the content (mass%) of the other metal elements in terms of oxide or metal is determined. Specifically, if the other metal elements are metal elements other than noble metal elements, the content (mass%) of those metal elements in terms of oxides is determined. If the other metal elements are noble metal elements (e.g., Ru, Os, Ir, Au, Ag, etc.), the content (mass%) of those noble metal elements in terms of metals is determined. From the analysis results of multiple (e.g., 50) Al-based oxides and supported elements, the average value of the content (mass%) of each metal element in terms of oxides or metals is determined, and ratio A is calculated using the following formula. Ratio A = (Average content of Group 1 elements in terms of oxide equivalent) / (Sum of average content of all constituent elements of Al-based oxide particles in terms of oxide equivalent)

[0065] The following explains how to find Q12.

[0066] Q12 can be found using the following formula. Q12 = (Total mass of all Group 1 elements in oxide form) / (Mass of this composition) × 100

[0067] If information on the raw materials used in the manufacture of this composition is known, the total mass of all Group 1 elements in terms of oxides and the mass of this composition can be determined from the raw material information.

[0068] If information on the raw materials used in the manufacture of this composition is not available, the total mass of all Group 1 elements in terms of oxides and the mass of this composition are determined by the ICP-AES method described below.

[0069] From the viewpoint of more effectively increasing the amount of CO2 adsorbed, the percentage of the mass of the Group 2 elements supported on the Al oxide in terms of metal equivalent, relative to the total mass of all Group 2 elements in terms of metal equivalent, in this composition (hereinafter referred to as "percentage Q2") is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more. The upper limit may be 100% by mass or less than 100% by mass. Percentage Q2 is determined in the same manner as percentage Q1.

[0070] From the viewpoint of more effectively increasing the amount of CO2 adsorbed, it is preferable that the first group of elements consist of one or more elements selected from Na and K.

[0071] From the viewpoint of more effectively increasing the amount of CO2 adsorbed, it is preferable that the second group of elements consist of one or more elements selected from Pt and Co.

[0072] Pt and Co, both in their metallic and oxide states, promote the progression of the reaction to form basic sites. However, the effect of Pt is greater in the metallic state than in the oxide state, and the effect of Co is greater in the oxide state than in the metallic state. On the other hand, K has a greater effect than Na in converting Pt and Co to oxides. Therefore, it is preferable to use Pt in combination with Na rather than with K, and it is preferable to use Co in combination with K rather than with Na. In other words, from the viewpoint of more effectively increasing the amount of CO2 adsorbed, it is preferable that the first group element is composed of Na and the second group element is composed of Pt, or that the first group element is composed of K and the second group element is composed of Co.

[0073] From the viewpoint of more effectively increasing the amount of CO2 adsorbed, the combination of K and Co is preferable to the combination of Na and Pt. On the other hand, as will be described later, when this composition is used as a catalyst for hydrocarbon production, the combination of Na and Pt is preferable to the combination of K and Co from the viewpoint of producing hydrocarbons more efficiently. The reason is as follows: Pt has the effect of converting CO2 to CO. CO has a higher activity than CO2 in reacting with reducing gases to produce hydrocarbons. Therefore, the combination of Na and Pt can produce hydrocarbons more efficiently than the combination of K and Co.

[0074] From the viewpoint of more effectively increasing the amount of CO2 adsorption, R1 / R2 is preferably 2 to 5.5, more preferably 2.5 to 5, and even more preferably 3 to 4.5.

[0075] From the viewpoint of more effectively increasing the amount of CO2 adsorption, R1 is preferably 0.2 to 0.9, more preferably 0.2 to 0.86, even more preferably 0.4 to 0.86, and even more preferably 0.6 to 0.8.

[0076] From the perspective of more effectively increasing the amount of CO2 adsorption, this composition is based on the following formula (2): 1 ≤ R³ ···(2) It is preferable that the following conditions be met.

[0077] In formula (2), R3 represents the ratio of the mass of Al in this composition on an Al2O3 basis to the sum of the mass of the Group 1 elements on an oxide basis and the mass of the Group 2 elements on a metallic basis. The methods for determining "the mass of Al on an Al2O3 basis," "the mass of the Group 1 elements on an oxide basis," and "the mass of the Group 2 elements on a metallic basis" will be described later.

[0078] From the viewpoint of improving the heat resistance of this composition, R3 is preferably 4 or more, more preferably 5 or more, and even more preferably 6 or more. From the viewpoint of more effectively increasing the amount of CO2 adsorbed, R3 is preferably 30 or less, more preferably 20 or less, and even more preferably 8 or less. Each of these upper limits may be combined with any of the lower limits mentioned above.

[0079] "Mass of Al in terms of Al2O3" means the mass of Al derived from one Al source if the composition contains one Al source, and the total mass of Al derived from two or more Al sources in terms of Al2O3 if the composition contains two or more Al sources.

[0080] From the viewpoint of improving the heat resistance of this composition, it is preferable that this composition contains an Al-based oxide as an Al source. This composition may also contain one or more Al sources other than Al-based oxides. Examples of Al sources other than Al-based oxides include alumina binder.

[0081] From the viewpoint of improving the heat resistance of this composition, the percentage of the mass of Al derived from Al-based oxides (in terms of Al2O3) relative to the total mass of all Al in this composition (hereinafter referred to as "percentage S1") is preferably 80% by mass or more, more preferably 85% by mass or more, and even more preferably 90% by mass or more. The upper limit may be 100% by mass or less than 100% by mass. If information on the raw materials used in the manufacture of this composition is known, percentage S1 can be determined from the raw material information.

[0082] From the perspective of more effectively increasing the amount of CO2 adsorption, this composition is based on the following formula (3): 0.7 ≤ R₄ ···(3) It is preferable that the following conditions be met.

[0083] In formula (3), R4 represents the ratio of the total mass of Al (in terms of Al2O3), the mass of the first group element (in terms of oxide), and the mass of the second group element (in terms of metal) to the mass of the composition. The methods for determining "the mass of Al (in terms of Al2O3)", "the mass of the first group element (in terms of oxide)", "the mass of the second group element (in terms of metal)", and "the mass of the composition" will be described later.

[0084] From the viewpoint of more effectively increasing the amount of CO2 adsorption, R4 is preferably 0.75 or higher, more preferably 0.8 or higher, and even more preferably 0.85 or higher. The upper limit may be 1 or less. The upper limit may be, for example, 0.98 or lower, or 0.95 or lower. Each of these upper limits may be combined with any of the lower limits mentioned above.

[0085] The following explains how to determine the "mass of Al in terms of Al2O3," the "mass of Group 1 elements in terms of oxides," and the "mass of Group 2 elements in terms of metals" in this composition.

[0086] If information on the raw materials used in the manufacture of this composition is known, the mass of Al in terms of Al2O3, the mass of the first group elements in terms of oxides, and the mass of the second group elements in terms of metals in this composition can be determined from the information on the raw materials.

[0087] If information on the raw materials used in the manufacture of this composition is not available, the mass of Al in terms of Al2O3, the mass of Group 1 elements in terms of oxides, and the mass of Group 2 elements in terms of metals in this composition can be determined using inductively coupled plasma atomic emission spectroscopy (ICP-AES). Specifically, the mass of each metal element in the molten product obtained by melting this composition by alkaline melting, etc., is measured using ICP-AES, and the mass of Al in terms of Al2O3 is determined from the mass of Al, the mass of Group 1 elements in terms of oxides is determined from the mass of Group 1 elements, and the mass of Group 2 elements in terms of metals is determined from the mass of Group 2 elements.

[0088] The method for determining the "mass of this composition" is explained below.

[0089] If information on the raw materials used in the manufacture of this composition is known, the mass of each metal element contained in this composition can be determined from the raw material information.

[0090] If information on the raw materials used in the manufacture of this composition is unknown, the mass of each metal element contained in this composition is determined using ICP-AES. Specifically, the mass of each metal element in the molten material obtained by melting this composition by alkali melting or the like is measured using ICP-AES.

[0091] The mass of Al in terms of Al2O3 is calculated from the mass of Al, the mass of the elements in the first group in terms of oxides is calculated from the mass of the elements in the first group, and the mass of the elements in the second group in terms of metals is calculated from the mass of the elements in the second group. If the composition contains other metal elements, the mass of those metal elements in terms of oxides or metals is calculated from the mass of those metal elements. Specifically, if the other metal elements are metal elements other than noble metals, the mass of those metal elements in terms of oxides is calculated from the mass of those metal elements, and if the other metal elements are noble metals (e.g., Ru, Os, Ir, Au, Ag, etc.), the mass of those noble metal elements in terms of metals is calculated from the mass of those noble metals. The mass of each metal element in terms of oxides or metals is calculated in this way, and the sum of the calculated masses is taken as the mass of the composition. The meaning of "oxide" for metal elements other than noble metals is as described above.

[0092] The method for producing this composition will be described below.

[0093] An example of a method for producing this composition is as follows: A first slurry is prepared by mixing an Al-containing oxide, a source of Group 1 elements, a solvent, and optionally other components (e.g., inorganic oxides, binders, etc.). The first slurry is dried and calcined to obtain a first calcined product. A second slurry is prepared by mixing the obtained first calcined product, a source of Group 2 elements, a solvent, and optionally other components (e.g., inorganic oxides, binders, etc.). The second slurry is dried and calcined to obtain a second calcined product. Desired components (e.g., binders, etc.) may be added to the obtained second calcined product. This composition may be the second calcined product, or a mixture of the second calcined product and desired components (e.g., binders, etc.).

[0094] For example, acetates, nitrates, hydroxides, and carbonates of Group 1 elements can be used as sources. When acetates, nitrates, or hydroxides are used, they become oxides upon calcination. The oxides can react with CO2 in the air to form carbonates. When carbonates are used, they remain unchanged after calcination.

[0095] As a source of Group 2 elements, for example, salts of Group 2 elements can be used. Examples of Group 2 element salts include nitrates, ammine complex salts, acetates, and chlorides.

[0096] Examples of solvents include water and organic solvents.

[0097] The drying temperature is, for example, between 50°C and 200°C, and the drying time is, for example, between 0.1 hours and 10 hours. The firing temperature is, for example, between 300°C and 800°C, and the firing time is, for example, between 0.1 hours and 10 hours. Firing can be carried out, for example, in an air atmosphere.

[0098] ≪Catalysts for hydrocarbon production≫ The following describes the catalyst for hydrocarbon production (hereinafter referred to as "this catalyst").

[0099] This catalyst comprises a first composition and a second composition.

[0100] The first composition includes the present composition. The first composition may consist of the present composition. The description of the present composition is as stated above.

[0101] The second composition contains Ce and a third group element.

[0102] Ce is present in the second composition in the form of an oxide containing Ce.

[0103] Oxides containing Ce are usually in particulate form. Examples of Ce-containing oxides include Ce-based oxides and ceria binders. From the viewpoint of improving the heat resistance of the second composition, it is preferable that at least a portion of the Ce is present in the second composition in the form of a Ce-based oxide.

[0104] Ce-based oxides are distinguished from ceria (ceria binders), which are used as binders, by having a particle size suitable for use as a support for Group 3 elements. From the viewpoint of improving support properties, it is preferable that Ce-based oxides are porous.

[0105] The average particle size of Ce-based oxides is preferably 1 μm to 150 μm, more preferably 2 μm to 100 μm, and even more preferably 3 μm to 50 μm. The method for measuring the average particle size of Ce-based oxides is the same as the method for measuring the average particle size of Al-based oxides.

[0106] Ce-based oxides may contain one or more metallic elements other than Ce (hereinafter referred to as "additional element M2"). Additional element M2 can be selected from, for example, rare earth elements other than Ce (e.g., Y, Pr, La, Nd, Sm, Eu, Gd, etc.), alkaline earth metal elements (e.g., Mg, Ca, Sr, Ba, etc.), Fe, Mn, Zr, Al, etc.

[0107] In Ce-based oxides, the additional element M2 may form a solid solution phase (for example, a solid solution phase of CeO2 and an oxide of the additional element M2), a single phase which is either a crystalline or amorphous phase (for example, an oxide phase of the additional element M2), or both a solid solution phase and a single phase. However, it is preferable that at least a portion of the additional element M2 forms a solid solution phase.

[0108] Examples of Ce-based oxides include ceria (CeO2), oxides obtained by modifying the surface of ceria with an additional element M2, and oxides obtained by solid-solving the additional element M2 in ceria.

[0109] The Ce-based oxide may be a Ce-based oxide in which the most abundant metal element by mass among the metal elements constituting the Ce-based oxide is Ce (hereinafter referred to as the "first Ce-based oxide"), or a Ce-based oxide in which the most abundant metal element by mass among the metal elements constituting the Ce-based oxide is a metal element other than Ce (hereinafter referred to as the "second Ce-based oxide"), or a mixture of the first and second Ce-based oxides.

[0110] From the viewpoint of improving the heat resistance of the second composition, the percentage of the mass of the first Ce-based oxide relative to the total mass of all Ce-based oxides in the second composition (hereinafter referred to as "percentage P2") is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more. The upper limit may be 100% by mass or less than 100% by mass. Percentage P2 is determined in the same manner as percentage P1.

[0111] From the viewpoint of improving the heat resistance of the second composition, the content of Ce in the first Ce-based oxide in terms of CeO2 (hereinafter referred to as "content C2") is preferably 60% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more, based on the mass of the first Ce-based oxide. The upper limit may be 100% by mass or less than 100% by mass.

[0112] The content C2 is calculated using the formula: (mass of Ce in the first Ce-based oxide converted to CeO2) / (mass of the first Ce-based oxide) × 100. The "mass of the first Ce-based oxide" refers to the total mass of oxides of the metal elements, assuming that each metal element in the first Ce-based oxide exists as an oxide. The meaning of "oxide" of a metal element is as described above. The content C2 is determined in the same way as the content C1.

[0113] The third group of elements consists of one or more elements that have the ability to reduce CO2 and / or CO to produce hydrocarbons (hereinafter referred to as "hydrocarbon production activity"). The third group of elements may consist of one type of element or two or more types of elements.

[0114] The phrase "the action of reducing CO2 and / or CO to produce hydrocarbons" refers to the catalytic action that promotes the production of hydrocarbons through the reaction of CO2 and / or CO with a reducing gas.

[0115] Hydrocarbons include chain-type saturated hydrocarbons (alkanes), chain-type unsaturated hydrocarbons (alkenes and alkynes), cyclic saturated hydrocarbons (cycloalkanes), and cyclic unsaturated hydrocarbons (cycloalkenes and cycloalkynes). The number of carbon atoms in hydrocarbons is, for example, between 1 and 100.

[0116] The hydrocarbon is preferably an alkane. The number of carbon atoms in the alkane is preferably 1 to 30, more preferably 1 to 20, even more preferably 1 to 10, and most preferably 1.

[0117] Examples of reducing gases include H2, NH3, and hydrazine. The reducing gas is preferably H2.

[0118] The third group of elements preferably have catalytic activity that promotes the formation of alkanes (especially methane) by the reaction of CO2 and / or CO with a reducing gas (especially H2).

[0119] The reaction between CO2 and H2 to produce methane is represented by the following equation. CO2 + 4H2 → CH4 + 2H2O

[0120] Examples of third-group elements include Ni, Ru, Rh, Pt, Pd, Ag, Cu, Mn, Co, and Fe. In one embodiment, the third-group elements consist of one or more elements selected from Ni and Ru.

[0121] When Ni is used in combination with an oxide containing Ce, a component with CO2 adsorption capacity, the hydrocarbon formation promoting effect of Ni is significantly enhanced by a synergistic effect. On the other hand, Ru does not exhibit such a synergistic effect. Therefore, it is preferable that the third group element be Ni.

[0122] The third group elements are present in the second composition in the form of active components capable of exhibiting hydrocarbon generation activity, for example, in one or more forms selected from metals, alloys, oxides, and carbonates. From the viewpoint of more effectively exhibiting hydrocarbon generation activity, it is preferable that the third group elements are present in the second composition in one or more forms selected from metals, alloys, oxides, and carbonates. The active components are, for example, particulate. The oxide of Ni is NiO, and the oxide of Ru is RuO2.

[0123] The first composition and the second composition can each take the form of a powder, pellets, or the like.

[0124] The first and second compositions may each contain components such as a binder and a stabilizer. Examples of binders include inorganic oxide binders such as alumina binder, ceria binder, zirconia binder, titania binder, and silica binder. Examples of stabilizers include nitrates, carbonates, oxides, and sulfates of alkaline earth metal elements (e.g., Sr, Ba, etc.).

[0125] A reduction treatment may be performed on this catalyst before use. When a reduction treatment is performed on this catalyst, the oxides of the group 2 elements in the first composition and the oxides of the group 3 elements in the second composition are reduced to a metallic state.

[0126] In one embodiment, the catalyst is a mixture of a first composition and a second composition. The mixture may contain components other than the first and second compositions. The mixture can take the form of a powder, pellets, or the like.

[0127] In another embodiment, the catalyst comprises a substrate having a first substrate portion and a second substrate portion, a first catalyst layer provided on the first substrate portion, and a second catalyst layer provided on the second substrate portion, wherein the first catalyst layer contains the first composition and the second catalyst layer contains the second composition.

[0128] The catalysts 1A and 1B described later according to the first and second embodiments are specific examples of the latter embodiment.

[0129] When this catalyst is used in a closed space (zero gravity environment) such as a spacecraft or space station, the latter embodiment is advantageous over the former embodiment in that it is easier to handle. Furthermore, the latter embodiment is advantageous over the former embodiment in that it results in less pressure loss during gas flow.

[0130] The performance of this catalyst will be explained below.

[0131] When the first composition is brought into contact with CO2, the first composition adsorbs the CO2. Therefore, the first composition can be used to recover CO2. Because the first composition contains this composition, it has improved CO2 recovery performance.

[0132] After recovering CO2 with the first composition, the second composition is brought into contact with a reducing gas while the catalyst is heated. The first composition releases CO2 (the CO2 may be converted to CO by the second group elements (e.g., Pt) in the first composition), and the third group elements in the second composition promote the production of hydrocarbons by the reaction of CO2 and / or CO with the reducing gas. Therefore, the second composition can be used to produce hydrocarbons.

[0133] Due to the performance characteristics of the first and second compositions, this catalyst can be used to produce hydrocarbons.

[0134] As described above, the composition begins releasing CO2 adsorbed on it at temperature T0 and ends at temperature T1. The first composition, containing the composition, has the same effect. Therefore, if temperature T2 is the temperature at which the second composition begins to exhibit hydrocarbon production activity (i.e., the temperature at which the second composition begins to produce hydrocarbons), then it is preferable that temperature T2 is lower than temperature T1. Note that temperature T1 may change depending on the amount of CO2 adsorbed on the composition, the heating rate of the composition, and the space velocity of the gas flowing through the reaction chamber containing the composition when the composition releases CO2.

[0135] In one embodiment, temperature T2 is greater than or equal to temperature T0 and less than temperature T1. In another embodiment, temperature T2 is less than temperature T0. In the former embodiment, the difference between temperature T1 and temperature T2 (temperature T1 - temperature T2) is preferably 50°C or more and 450°C or less, more preferably 50°C or more and 350°C or less, and even more preferably 100°C or more and 250°C or less. In the latter embodiment, the difference between temperature T1 and temperature T2 (temperature T1 - temperature T2) is preferably 100°C or more and 550°C or less, more preferably 150°C or more and 500°C or less, and even more preferably 200°C or more and 450°C or less. In these embodiments, the first composition and the second composition do not need to be placed in separate reaction chambers as in Patent Documents 1 and 2, but can be placed in the same reaction chamber. In other words, by controlling the temperature in the same reaction chamber where the first and second compositions are placed to a temperature T31 between T2 and T1 in the former embodiment, and to a temperature T32 between T0 and T2 in the latter embodiment, the release of CO2 from the first composition and the production of hydrocarbons by the second composition can be achieved simultaneously. Temperature T31 is preferably 150°C to 500°C, more preferably 170°C to 450°C, and even more preferably 200°C to 400°C. Temperature T32 is preferably 150°C to 600°C, more preferably 170°C to 550°C, and even more preferably 200°C to 500°C.

[0136] If temperature T2 is above temperature T1, the second composition will begin to exhibit hydrocarbon production activity only after the release of CO2 from the first composition is complete. Therefore, it is not possible to simultaneously achieve the release of CO2 from the first composition and the production of hydrocarbons by the second composition. Consequently, when the first and second compositions are placed in the same reaction chamber, the chamber requires space to retain the CO2 released from the first composition until the second composition begins to exhibit hydrocarbon production activity.

[0137] When a first composition and a second composition installed in the same reaction chamber can simultaneously release CO2 from the first composition and produce hydrocarbons from the second composition, space savings can be achieved, making it suitable for use in enclosed spaces such as spacecraft and space stations.

[0138] To achieve a temperature T2 lower than temperature T1 (hereinafter referred to as "desired temperature T2"), it is necessary for components other than the group 3 elements in the second composition to adsorb CO2 with a moderate strength. If the adsorption is too weak, the CO2 concentration near the group 3 elements cannot be increased. If the adsorption is too strong, the CO2 remains bound to the component, and the CO2 and group 3 elements cannot react. Therefore, Ce is used in the second composition. Oxides containing Ce can adsorb CO2 with a moderate strength. Thus, the desired temperature T2 can be achieved.

[0139] The following describes preferred embodiments of this catalyst.

[0140] Pt has the effect of converting CO2 to CO. CO has a higher activity than CO2 in reacting with reducing gases to produce hydrocarbons. Therefore, from the viewpoint of producing hydrocarbons more efficiently, the embodiment in which the first group element in the first composition is composed of Na and the second group element in the first composition is composed of Pt is preferred over the embodiment in which the first group element in the first composition is composed of K and the second group element in the first composition is composed of Co.

[0141] From the viewpoint of more effectively achieving the desired temperature T2, it is preferable that the second composition includes a Ce-based oxide (particularly the first Ce-based oxide), and at least a portion of the third group elements are supported on the Ce-based oxide (particularly the first Ce-based oxide). The meaning and method of confirmation of "supported" are the same as described above.

[0142] From the viewpoint of more effectively achieving the desired temperature T2, the percentage of the mass of the third group elements supported on the Ce oxide in terms of metal equivalent, relative to the total mass of all third group elements in terms of metal equivalent, in the second composition (hereinafter referred to as "percentage Q3") is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more. The upper limit may be 100% by mass or less than 100% by mass. Percentage Q3 is determined in the same manner as percentage Q1.

[0143] "Metallic mass of Group 3 elements" means the metallic mass of a single element if Group 3 elements consist of only one element, and the total metallic mass of two or more elements if Group 3 elements consist of two or more elements.

[0144] The second composition may contain a support other than a Ce-based oxide, and at least a portion of the third group elements may be supported on a support other than a Ce-based oxide.

[0145] Other supports besides Ce-based oxides can be selected from inorganic oxides. Examples of inorganic oxides include oxides of rare earth elements other than Ce, zirconia (ZrO2), silica (SiO2), titania (TiO2), zeolite (aluminosilicate), and oxides based on MgO, ZnO, SnO2, etc.

[0146] From the viewpoint of more effectively achieving the desired temperature T2, the second composition is given by the following formula (5): 1 ≤ R5 ≤ 500 ···(5) It is preferable that the following conditions be met.

[0147] In equation (5), R5 represents the ratio of the mass of Ce in the second composition (calculated as CeO2) to the mass of the third group element (calculated as metal). The methods for determining the "mass of Ce in CeO2" and the "mass of the third group element (calculated as metal)" will be described later.

[0148] From the viewpoint of more effectively achieving the desired temperature T2, R5 is preferably 2 to 450, more preferably 3 to 400, and even more preferably 4 to 350.

[0149] "Mass of Ce in terms of CeO2" means the mass of Ce derived from one Ce source if the second composition contains one Ce source, and the total mass of Ce derived from two or more Ce sources in terms of CeO2 if the second composition contains two or more Ce sources.

[0150] The second composition preferably contains a Ce-based oxide as a Ce source. The second composition may also contain one or more Ce sources other than Ce-based oxides. Examples of Ce sources other than Ce-based oxides include ceria binders.

[0151] From the viewpoint of improving the heat resistance of the second composition, the percentage of the mass of Ce derived from Ce-based oxides in terms of CeO2 (hereinafter referred to as "percentage S2") relative to the total mass of all Ce in terms of CeO2 in the second composition is preferably 80% by mass or more, more preferably 85% by mass or more, and even more preferably 90% by mass or more. The upper limit may be 100% by mass or less than 100% by mass. If information on the raw materials used in the manufacture of the second composition is known, percentage S2 can be determined from the raw material information.

[0152] From the viewpoint of more effectively achieving the desired temperature T2, the second composition is given by the following formula (6): 0.7 ≤ R6 ···(6) It is preferable that the following conditions be met.

[0153] In equation (6), R6 represents the ratio of the total mass of Ce (calculated as CeO2) and the total mass of the third group elements (calculated as metal) to the total mass of the second composition. The methods for determining the "mass of Ce (calculated as CeO2)" and the "mass of the third group elements (calculated as metal)" will be described later.

[0154] From the viewpoint of more effectively achieving the desired temperature T2, R6 is preferably 0.8 or higher, more preferably 0.85 or higher, and even more preferably 0.9 or higher. The upper limit may be 1 or less. The upper limit may be, for example, 0.98 or lower, or 0.95 or lower. Each of these upper limits may be combined with any of the lower limits described above.

[0155] The following explains how to determine the "mass of Ce in terms of CeO2" and the "mass of the third group elements in terms of metal" in the second composition.

[0156] If information on the raw materials used in the manufacture of the second composition is known, the mass of Ce in the second composition in terms of CeO2 and the mass of the third group elements in terms of metal can be determined from the raw material information.

[0157] If information on the raw materials used in the manufacture of the second composition is unknown, the mass of Ce in the second composition (in terms of CeO2 equivalent) and the mass of the third group elements (in terms of metal equivalent) can be determined using ICP-AES. Specifically, the mass of each metal element in the molten material obtained by melting the second composition by alkali melting, etc., is measured using ICP-AES, and the mass of Ce in terms of CeO2 is determined from the mass of Ce, and the mass of the third group elements (in terms of metal equivalent) is determined from the mass of the third group elements.

[0158] The method for determining the mass of the second composition is as follows:

[0159] If information on the raw materials used in the manufacture of the second composition is known, the mass of each metal element contained in the second composition is determined from the raw material information.

[0160] If information on the raw materials used in the manufacture of the second composition is unknown, the mass of each metal element contained in the second composition is determined using ICP-AES. Specifically, the mass of each metal element in the molten material obtained by melting the second composition by alkali melting or the like is measured using ICP-AES.

[0161] The mass of Ce in terms of CeO2 is determined from the mass of Ce, and the mass of the third group elements in terms of metal is determined from the mass of the third group elements. If the second composition contains other metal elements, the mass of those metal elements in terms of oxide or metal is determined from their mass. Specifically, if the other metal elements are metal elements other than noble metals, the mass of those metal elements in terms of oxide is determined from their mass, and if the other metal elements are noble metals (e.g., Pt, Pd, Rh, Os, Ir, Au, Ag, etc.), the mass of those noble metal elements in terms of metal is determined from their mass. The mass of each metal element in terms of oxide or metal is determined in this way, and the sum of the determined masses is taken as the mass of the second composition. The meaning of "oxide" for metal elements other than noble metals is as described above.

[0162] The method for producing the second composition will be described below.

[0163] An example of a method for producing the second composition is as follows: A third slurry is prepared by mixing an oxide containing Ce, a source of a group 3 element, a solvent, and optionally other components (e.g., inorganic oxide, binder, etc.). The third slurry is dried and calcined to obtain a third calcined product. Desired components (e.g., binder, etc.) may be added to the obtained third calcined product. The second composition may be the third calcined product or a mixture of the third calcined product and the desired components (e.g., binder, etc.).

[0164] As a source of Group 3 elements, for example, salts of Group 3 elements can be used. Examples of Group 3 element salts include nitrates, ammine complex salts, acetates, and chlorides.

[0165] Examples of solvents include water and organic solvents.

[0166] The drying temperature is, for example, between 50°C and 200°C, and the drying time is, for example, between 0.1 hours and 10 hours. The firing temperature is, for example, between 300°C and 800°C, and the firing time is, for example, between 0.1 hours and 10 hours. Firing can be carried out, for example, in an air atmosphere.

[0167] ≪Systems for Hydrocarbon Production≫ The hydrocarbon production system (hereinafter referred to as "the system of the present invention") will be described below.

[0168] The system of the present invention comprises a reaction chamber and the catalyst housed in the reaction chamber.

[0169] Embodiments of the system of the present invention will be described below with reference to the drawings. In the drawings, the gas flow direction is indicated by the symbol X. In this specification, the upstream side of the gas flow direction X may be referred to as the "gas inlet side" or "upstream side," and the downstream side of the gas flow direction X may be referred to as the "gas outlet side" or "downstream side." In this specification, "length" means the dimension of the gas flow direction X unless otherwise specified.

[0170] The following describes a system 100 according to one embodiment of the present invention, based on Figure 1.

[0171] The system 100 comprises a reaction chamber 41 and a hydrocarbon production catalyst 1 housed in the reaction chamber 41.

[0172] System 100 includes a reactor 4, and the reaction chamber 41 is formed inside the reactor 4.

[0173] The reactor 4 has a gas inlet 42 and a gas outlet 43. The gas inlet 42 is located at one end (upstream side) of the reactor 4, and the gas outlet 43 is located at the other end (downstream side) of the reactor 4.

[0174] The system 100 may also include a gas supply means 5.

[0175] The gas supply means 5 includes a gas supply pipe 50, one end of which is connected to the gas inlet 42 of the reactor 4; a first gas supply source 51 that supplies gas G1 to the gas supply pipe 50; and a second gas supply source 52 that supplies gas G2 to the gas supply pipe 50.

[0176] The gas G1 supplied from the first gas source 51 to the gas supply pipe 50 is supplied to the reaction chamber 41 through the gas inlet 42 of the reactor 4.

[0177] Gas G1 contains CO2. Gas G1 may also contain components other than CO2. Examples of components other than CO2 include inert gases (e.g., He, Ar, N2, etc.), CO, O2, H2O, NH3, and volatile organic compounds (e.g., CH4, acetone, acetaldehyde, etc.). The CO2 and inert gas content in Gas G1 can be adjusted as appropriate. The CO2 content is, for example, 0.01% to 100% by volume, preferably 0.1% to 20% by volume, based on the volume of Gas G1. The inert gas content is, for example, 0% to 99.8% by volume, preferably 10% to 99% by volume, based on the volume of Gas G1. Gas G1 may be exhaust gas or a gas in a closed space where humans live (e.g., a spacecraft, a space station, etc.) (e.g., a gas containing accumulated CO2 from human breath).

[0178] As the first gas supply source 51, for example, a cylinder containing gas G1, a device that generates gas G1, etc., can be used.

[0179] The gas G2 supplied from the second gas source 52 to the gas supply pipe 50 is supplied to the reaction chamber 41 through the gas inlet 42 of the reactor 4.

[0180] Gas G2 contains a reducing gas. The reducing gas is not particularly limited as long as it can reduce CO2 to hydrocarbons (especially methane). Examples of reducing gases include H2, NH3, and hydrazine. The reducing gas is preferably H2. Gas G2 may also contain components other than reducing gases. Examples of components other than reducing gases include inert gases (e.g., He, Ar, N2, etc.) and hydrocarbons (e.g., methane, etc.). The content of reducing gases and inert gases in gas G2 can be adjusted as appropriate. The content of reducing gases is, for example, 0.2% to 100% by volume, preferably 1% to 100% by volume, based on the volume of gas G2. The content of inert gases is, for example, 0% to 99.8% by volume, preferably 10% to 99% by volume, based on the volume of gas G2.

[0181] As the second gas supply source 52, for example, a cylinder containing gas G2, a device that generates gas G2, etc., can be used.

[0182] The gas supply means 5 may include a third gas supply source 53 that supplies gas G3 to the gas supply pipe 50. The gas G3 supplied from the third gas supply source 53 to the gas supply pipe 50 is supplied to the reaction chamber 41 through the gas inlet 42 of the reactor 4. Gas G3 can be used, for example, as a purge gas. Examples of gas G3 include inert gases such as He, Ar, and N2. The third gas supply source 53 can be, for example, a cylinder containing gas G3, a device that generates gas G3, or the like.

[0183] The gas supply means 5 may include a pump (not shown) installed in the gas supply pipe 50. The gas supply means 5 can, for example, supply gases G1, G2, and G3 to the reaction chamber 41 by utilizing the suction and discharge forces of the pump.

[0184] The system 100 may include a temperature control means 6 for controlling the temperature of the catalyst 1. The temperature control means 6 is, for example, a temperature control device (e.g., a furnace such as an electric furnace) surrounding the reactor 4. The temperature control means 6 can raise or lower the temperature of the catalyst 1 by heating or cooling the reactor 4.

[0185] The system 100 may include an exhaust pipe 7 for discharging gas (for example, hydrocarbon G4 produced from CO2 and reducing gas by the action of catalyst 1) from the reaction chamber 41. One end of the exhaust pipe 7 is connected to the gas outlet 43 of the reactor 4.

[0186] Catalyst 1 is this catalyst.

[0187] The following describes an embodiment of catalyst 1 based on Figures 2 to 7.

[0188] <First Embodiment> The catalyst 1A according to the first embodiment will be described below with reference to Figures 2 to 6.

[0189] Catalyst 1A comprises a substrate 10 having a first substrate portion 10a and a second substrate portion 10b, a first catalyst layer 20 provided on the first substrate portion 10a, and a second catalyst layer 30 provided on the second substrate portion 10b.

[0190] Catalyst 1A comprises a substrate 10.

[0191] The base material 10 extends in the gas flow direction X.

[0192] The substrate 10 is housed in the reaction chamber 41 such that the axial direction of the substrate 10 coincides with or substantially coincides with the gas flow direction X.

[0193] The base material 10 has a first base material portion 10a and a second base material portion 10b.

[0194] The first base material portion 10a is located on the upstream side of the gas flow direction X, and the second base material portion 10b is located on the downstream side of the gas flow direction X.

[0195] The first base material portion 10a and the second base material portion 10b each extend in the gas flow direction X and have an end on the gas inlet side and an end on the gas outlet side.

[0196] The first base material section 10a and the second base material section 10b are housed in the reaction chamber 41 such that their axial directions coincide with or substantially coincide with the gas flow direction X.

[0197] The axial direction of the first base material portion 10a and the axial direction of the second base material portion 10b may coincide or substantially coincide.

[0198] The first base material portion 10a and the second base material portion 10b are integral, and the gas outlet end of the first base material portion 10a and the gas inlet end of the second base material portion 10b are continuous. In Figure 6, the boundary between the gas outlet end of the first base material portion 10a and the gas inlet end of the second base material portion 10b is indicated by the symbol S.

[0199] In the following, the common features of the first base material part 10a and the second base material part 10b will be explained together with the explanations for the first base material part 10a and the second base material part 10b. In doing so, expressions such as "base material part 10a, 10b", "cylindrical part 11a, 11b", "partition part 12a, 12b", "cell 13a, 13a", and "length L10a, L10b" will be used. For the first base material part 10a, these expressions mean "base material part 10a", "cylindrical part 11a", "partition part 12a", "cell 13a", and "length L10a", and for the second base material part 10b, they mean "base material part 10b", "cylindrical part 11b", "partition part 12b", "cell 13b", and "length L10b".

[0200] The materials constituting the base materials 10a and 10b can be appropriately selected from known materials. Examples of materials constituting the base materials 10a and 10b include ceramic materials and metallic materials, but ceramic materials are preferred. Examples of ceramic materials include carbide ceramics such as silicon carbide, titanium carbide, tantalum carbide, and tungsten carbide; nitride ceramics such as aluminum nitride, silicon nitride, boron nitride, and titanium nitride; and oxide ceramics such as alumina, zirconia, cordierite, mullite, zircon, aluminum titanate, and magnesium titanate. Examples of metallic materials include alloys such as stainless steel.

[0201] The materials constituting the base material 10a and the materials constituting the base material 10b are usually the same.

[0202] The base material parts 10a and 10b have cylindrical parts 11a and 11b, partition wall parts 12a and 12b provided within the cylindrical parts 11a and 11b, and cells 13a and 13b separated by the partition wall parts 12a and 12b. The base material parts 10a and 10b are preferably honeycomb structures.

[0203] The cylindrical portions 11a and 11b define the outer shape of the base material portions 10a and 10b, and the axial direction of the cylindrical portions 11a and 11b coincides with the axial direction of the base material portions 10a and 10b. The shape of the cylindrical portions 11a and 11b may be cylindrical, or it may be an elliptical cylinder, a polygonal cylinder, or other shape.

[0204] The partition sections 12a and 12b are provided within the cylindrical sections 11a and 11b. Partition sections 12a and 12b exist between adjacent cells 13a and 13b, and adjacent cells 13a and 13b are separated by the partition sections 12a and 12b. The partition sections 12a and 12b may have a porous structure through which gas can pass. The thickness of the partition sections 12a and 12b is, for example, 20 μm or more and 1500 μm or less.

[0205] Cells 13a and 13b extend in the gas flow direction X and have an end on the gas inlet side and an end on the gas outlet side. Both the gas inlet side and the gas outlet side of cells 13a and 13b are open.

[0206] The gas outlet end (opening) of cell 13a and the gas inlet end (opening) of cell 13b are continuous such that one gas flow path is formed by one cell 13a and one cell 13b, extending in the gas flow direction X.

[0207] Gas flowing into cell 13a from the gas inlet end (opening) of cell 13a flows out from the gas outlet end (opening) of cell 13a. Gas flowing out from the gas outlet end (opening) of cell 13a flows into cell 13b from the gas inlet end (opening) of cell 13b and flows out from the gas outlet end (opening) of cell 13b. This type of system is called a flow-through system.

[0208] The plan view shape of the gas inlet end (opening) of cells 13a and 13b is a rectangle, but it may be a hexagon, octagon, or other shape. The same applies to the plan view shape of the gas outlet end (opening) of cells 13a and 13b.

[0209] The cell density per square inch of the base material parts 10a and 10b is, for example, between 100 and 1000 cells. The cell density per square inch of the base material parts 10a and 10b refers to the total number of cells 13a and 13b per square inch in the cross-section obtained by cutting the base material parts 10a and 10b with a plane perpendicular to the gas flow direction X.

[0210] The base material parts 10a and 10b have lengths L10a and L10b.

[0211] The volume of the base material parts 10a and 10b is, for example, between 0.1 L and 20 L. The volume of the base material parts 10a and 10b refers to the apparent volume of the base material parts 10a and 10b. For example, if the base material parts 10a and 10b are cylindrical, and the outer diameter of the base material parts 10a and 10b is 2r, then the volume of the base material parts 10a and 10b is given by the formula: Volume of base material parts 10a and 10b = π × r 2 It is expressed as × (lengths L10a, L10b).

[0212] The percentage of the length L10a of the first base material part 10a to the sum of the lengths L10a of the first base material part 10a and the length L10b of the second base material part 10b is, for example, 10% or more and 90% or less, preferably 20% or more and 80% or less. In one example, the percentage of the length L10a of the first base material part 10a to the sum of the lengths L10a of the first base material part 10a and the length L10b of the second base material part 10b is 50%.

[0213] Catalyst 1A comprises a first catalyst layer 20 provided on the first substrate portion 10a.

[0214] The first catalyst layer 20 contains the first composition. The first catalyst layer 20 may also be composed of the first composition.

[0215] The first catalyst layer 20 is provided on the cell 13a side surface of the partition wall 12a. "Cell 13a side surface of the partition wall 12a" means the outer surface of the partition wall 12a extending in the gas flow direction X. The first catalyst layer 20 may be provided directly on the cell 13a side surface of the partition wall 12a or via another layer, but it is usually provided directly on the cell 13a side surface of the partition wall 12a.

[0216] The first catalyst layer 20 may consist of a portion that rises from the cell 13a-side surface of the partition wall 12a toward the cell 13a (hereinafter referred to as the "raised portion"), or it may consist of a portion that exists inside the partition wall 12a (hereinafter referred to as the "intrinsic portion"), or it may have both a raised portion and an intrinsic portion.

[0217] The first catalyst layer 20 extends along the gas flow direction X from the gas inlet end of the partition wall 12a to the gas outlet end of the partition wall 12a. The first catalyst layer 20 may extend along the gas flow direction X from the gas inlet end of the partition wall 12a without reaching the gas outlet end of the partition wall 12a, or it may extend along the direction opposite to the gas flow direction X from the gas outlet end of the partition wall 12a without reaching the gas inlet end of the partition wall 12a.

[0218] The mass of the first catalyst layer 20 per unit volume of the portion of the first base material 10a in which the first catalyst layer 20 is provided (mass after firing) is, for example, 20 g / L or more and 400 g / L or less, preferably 30 g / L or more and 300 g / L or less.

[0219] The mass of the first catalyst layer 20 per unit volume of the portion of the first substrate part 10a in which the first catalyst layer 20 is provided is calculated using the formula: (mass of the first catalyst layer 20) / ((volume of the first substrate part 10a) × (average length L20 of the first catalyst layer 20 / length L10a of the first substrate part 10a)).

[0220] An example of a method for measuring the average length L20 of the first catalyst layer 20 is as follows:

[0221] A sample is cut from the first base material 10a, extending in the axial direction of the first base material 10a and having the same length L10a as the first base material 10a. The sample is, for example, cylindrical with a diameter of 25.4 mm. The diameter of the sample can be changed as needed. If the first catalyst layer 20 extends from the gas inlet end of the partition wall 12a along the gas flow direction X, the sample is cut at 5 mm intervals by a plane perpendicular to the axial direction of the first base material 10a, and the first cut piece, second cut piece, ..., nth cut piece are obtained in order from the gas inlet end of the sample. If the first catalyst layer 20 extends from the gas outlet end of the partition wall 12a along the direction opposite to the gas flow direction X, the sample is cut at 5 mm intervals by a plane perpendicular to the axial direction of the first base material 10a, and the first cut piece, second cut piece, ..., nth cut piece are obtained in order from the gas outlet end of the sample. In all cases, the length of the cut piece is 5 mm. The composition of the cut piece is analyzed using an X-ray fluorescence analyzer (XRF) (e.g., energy-dispersive X-ray spectrometer (EDX), wavelength-dispersive X-ray spectrometer (WDX), etc.), an inductively coupled plasma emission spectrometer (ICP-AES), a scanning electron microscope-energy-dispersive X-ray spectroscopy (SEM-EDX), etc., and based on the composition of the cut piece, it is confirmed whether or not the cut piece contains a portion of the first catalyst layer 20.

[0222] For sections that clearly contain a portion of the first catalyst layer 20, compositional analysis is not necessarily required. For example, the cross-section can be observed using a scanning electron microscope (SEM), electron beam microanalyzer (EPMA), etc., to confirm whether or not the section contains a portion of the first catalyst layer 20. Elemental mapping of the cross-section may also be performed when observing the cross-section.

[0223] After confirming whether the cut piece contains a portion of the first catalyst layer 20, the length of the first catalyst layer 20 contained in the sample is calculated based on the following formula. Length of the first catalyst layer 20 in the sample = 5 mm × (number of cut pieces containing a portion of the first catalyst layer 20)

[0224] For example, if the first to kth sections contain a portion of the first catalyst layer 20, but the (k+1) to nth sections do not, the total length of the first catalyst layer 20 contained in the sample is (5 × k) mm.

[0225] An example of a more detailed method for measuring the length of the first catalyst layer 20 contained in the sample is as follows:

[0226] The kth section (when the first catalyst layer 20 extends from the gas inlet end of the partition wall 12a along the gas flow direction X, this is the section containing a portion of the first catalyst layer 20 obtained from the gas outlet side of the sample; when the first catalyst layer 20 extends from the gas outlet end of the partition wall 12a along the direction opposite to the gas flow direction X, this is the section containing a portion of the first catalyst layer 20 obtained from the gas inlet side of the sample) is cut in the axial direction of the first substrate 10a, and the length of the portion of the first catalyst layer 20 present on the cut surface is measured by observing it using SEM, EPMA, etc. Then, the length of the portion of the first catalyst layer 20 in the kth section is calculated based on the following formula. Length of the first catalyst layer 20 in the sample = (5 mm × (k-1)) + (length of a portion of the first catalyst layer 20 in the k-th section)

[0227] For 8 to 16 samples arbitrarily cut from catalyst 1A, the length of the first catalyst layer 20 contained in each sample is measured, and the average value of these measurements is defined as the average length L20 of the first catalyst layer 20.

[0228] The percentage of the average length L20 of the first catalyst layer 20 to the length L10a of the first substrate portion 10a is, for example, 10% or more, preferably 20% or more. The upper limit may be 100%, or it may exceed 100%. If the gas outlet end of the first catalyst layer 20 overlaps with the gas inlet end of the second catalyst layer 30, this percentage may exceed 100%.

[0229] Catalyst 1A includes a second catalyst layer 30 provided on the second substrate portion 10b.

[0230] The second catalyst layer 30 contains the second composition. The second catalyst layer 30 may also be composed of the second composition.

[0231] The second catalyst layer 30 is provided on the cell 13b side surface of the partition wall 12b. "Cell 13b side surface of the partition wall 12b" means the outer surface of the partition wall 12b that extends in the gas flow direction X. The second catalyst layer 30 may be provided directly on the cell 13b side surface of the partition wall 12b or via another layer, but it is usually provided directly on the cell 13b side surface of the partition wall 12b.

[0232] The second catalyst layer 30 may consist of a portion that rises from the cell 13b side surface of the partition wall portion 12b toward the cell 13b side (hereinafter referred to as the "raised portion"), or it may consist of a portion that exists inside the partition wall portion 12b (hereinafter referred to as the "intrinsic portion"), or it may have both a raised portion and an intrinsic portion.

[0233] The second catalyst layer 30 extends from the gas outlet end of the partition wall 12b to the gas inlet end of the partition wall 12b, in a direction opposite to the gas flow direction X. The second catalyst layer 30 may extend from the gas outlet end of the partition wall 12b in a direction opposite to the gas flow direction X, without reaching the gas inlet end of the partition wall 12b, or it may extend from the gas inlet end of the partition wall 12b in the gas flow direction X, without reaching the gas outlet end of the partition wall 12b.

[0234] The gas outlet end of the first catalyst layer 20 and the gas inlet end of the second catalyst layer 30 are in contact at a boundary S. The boundary between the gas outlet end of the first catalyst layer 20 and the gas inlet end of the second catalyst layer 30 coincides with the boundary S between the gas outlet end of the first substrate portion 10a and the gas inlet end of the second substrate portion 10b.

[0235] The gas outlet end of the first catalyst layer 20 and the gas inlet end of the second catalyst layer 30 do not need to be in contact. In other words, a gap may be formed between the gas outlet end of the first catalyst layer 20 and the gas inlet end of the second catalyst layer 30.

[0236] The mass of the second catalyst layer 30 per unit volume of the portion of the second base material 10b in which the second catalyst layer 30 is provided (mass after firing) is, for example, 20 g / L or more and 400 g / L or less, more preferably 30 g / L or more and 300 g / L or less.

[0237] The mass of the second catalyst layer 30 per unit volume of the portion of the second base material 10b in which the second catalyst layer 30 is provided is calculated using the formula: (mass of the second catalyst layer 30) / ((volume of the second base material 10b) × (average length L30 of the second catalyst layer 30 / length L10b of the second base material 10b)).

[0238] The above explanation regarding the method for measuring the average length L20 of the first catalyst layer 20 also applies to the method for measuring the average length L30 of the second catalyst layer 30. When applying this, "first catalyst layer 20" is replaced with "second catalyst layer 30," and "average length L20" is replaced with "average length L30."

[0239] The percentage of the average length L30 of the second catalyst layer 30 to the length L10b of the second base material 10b is, for example, 10% or more, preferably 20% or more. The upper limit may be 100%, or it may exceed 100%. If the gas inlet end of the second catalyst layer 30 overlaps with the gas outlet end of the first catalyst layer 20, this percentage may exceed 100%.

[0240] Catalyst 1A can be manufactured by forming a first catalyst layer 20 on a first substrate portion 10a and a second catalyst layer 30 on a second substrate portion 10b.

[0241] The first catalyst layer 20 can be formed by mixing the raw materials and solvent for the first catalyst layer 20 to prepare a slurry for forming the first catalyst layer, applying the slurry for forming the first catalyst layer onto the first substrate portion 10a, and then drying and firing it.

[0242] The second catalyst layer 30 can be formed by mixing the raw materials and solvent for the second catalyst layer 30 to prepare a slurry for forming the second catalyst layer, applying the slurry for forming the second catalyst layer onto the second base material 10b, and then drying and firing it.

[0243] Examples of solvents include water and organic solvents.

[0244] The drying temperature is, for example, between 50°C and 200°C, and the drying time is, for example, between 0.1 hours and 10 hours. The firing temperature is, for example, between 300°C and 800°C, and the firing time is, for example, between 0.1 hours and 10 hours. Firing can be carried out, for example, in an air atmosphere.

[0245] <Second Embodiment> The catalyst 1B according to the second embodiment will be described below with reference to Figure 7.

[0246] In catalyst 1B, components identical to those in catalyst 1A are indicated by the same reference numerals as those in catalyst 1A. Unless otherwise specified below, the above description relating to catalyst 1A also applies to catalyst 1B.

[0247] Catalyst 1B differs from catalyst 1A, in that the first substrate portion 10a and the second substrate portion 10b are separate components, while catalyst 1B is an integrated component.

[0248] The present invention includes both embodiments in which the substrate 10 is composed of one substrate, such as catalyst 1A, and embodiments in which the substrate 10 is composed of two substrates, such as catalyst 1B.

[0249] The first base material section 10a and the second base material section 10b are housed in the reaction chamber 41 such that their axial directions coincide with or substantially coincide with the gas flow direction X.

[0250] The axial direction of the first base material portion 10a and the axial direction of the second base material portion 10b may coincide or substantially coincide.

[0251] A gap is formed between the gas outlet end of the first base material 10a and the gas inlet end of the second base material 10b. The distance between the gas outlet end of the first base material 10a and the gas inlet end of the second base material 10b is, for example, 5 mm or more and 5000 mm or less.

[0252] The phrase "the base material 10 extends in the gas flow direction X" includes embodiments in which a gap is formed between the gas outlet end of the first base material portion 10a and the gas inlet end of the second base material portion 10b, and the axial directions of the first base material portion 10a and the second base material portion 10b coincide with or substantially coincide with the gas flow direction X.

[0253] The gas outlet end of the first base material 10a and the gas inlet end of the second base material 10b may be in contact. In this case, the arrangement of the first base material 10a and the second base material 10b may be the same as, for example, the arrangement shown in Figure 6.

[0254] ≪Methods for producing hydrocarbons≫ The following describes embodiments of a hydrocarbon manufacturing method using System 100.

[0255] One embodiment of the method involves the following steps: (a) A step of supplying gas G1 to the reaction chamber 41; and (b) A process of supplying gas G2 to the reaction chamber 41 while heating the hydrocarbon catalyst 1. Includes.

[0256] Before starting step (a), a reduction treatment may be performed on catalyst 1. When a reduction treatment is performed on catalyst 1, the oxides of group 2 elements in the first catalyst layer 20 and the oxides of group 3 elements in the second catalyst layer 30 are reduced to a metallic state.

[0257] The reduction treatment can be carried out by supplying gas G2 to the reaction chamber 41. When gas G2 is supplied to the reaction chamber 41, the catalyst 1 is reduced by the reducing gas in gas G2. The reduction treatment time is, for example, 5 minutes or more and 120 minutes or less, preferably 10 minutes or more and 100 minutes or less. The temperature of the catalyst 1 during the reduction treatment is, for example, 200°C or more and 700°C or less, preferably 250°C or more and 650°C or less. The temperature control of the catalyst 1 can be carried out by the temperature control means 6. The supply of gas G2 to the reaction chamber 41 can be carried out by the gas supply means 5. The gas G2 supplied to the reaction chamber 41 is discharged from the reaction chamber 41 through the gas outlet 43 of the reactor 4. The supply of gas G2 to the reaction chamber 41 may be carried out continuously or intermittently.

[0258] In step (a), when gas G1 is supplied to the reaction chamber 41, the first catalyst layer 20 comes into contact with gas G1 and recovers CO2 in gas G1. The space velocity of gas G1 is, for example, 1h -1 or more and 100,000h -1 or less, preferably 100h -1 or more and 50,000h -1 or less. The space velocity of gas G1 is obtained by dividing the flow rate of gas G1 (m 3 h ―1 ) by the volume of the reaction chamber 41 (m 3 ). The supply time of gas G1 is, for example, 1 minute or more and 120 minutes or less, preferably 3 minutes or more and 60 minutes or less. The pressure in the reaction chamber 41 during CO2 recovery is, for example, 0.05 MPa or more and 5 MPa or less, preferably 0.08 MPa or more and 0.2 MPa or less. The temperature of the catalyst 1 during CO2 recovery is a temperature of 400°C or less, preferably -40°C or more and 400°C or less, more preferably 0°C or more and 300°C or less, and even more preferably 10°C or more and 200°C or less. The temperature control of the catalyst 1 can be carried out by the temperature control means 6. The supply of gas G1 to the reaction chamber 41 can be carried out by the gas supply means 5. The gas G1 supplied to the reaction chamber 41 is discharged from the reaction chamber 41 through the gas outlet 43 of the reactor 4. The supply of gas G1 to the reaction chamber 41 may be carried out continuously or intermittently, but it is preferably carried out continuously.

[0259] In step (b), when the catalyst 1 is heated and the gas G2 is supplied to the reaction chamber 41, the first catalyst layer 20 releases CO2 (CO2 may be converted to CO by the group 2 elements (e.g., Pt) in the first catalyst layer 20), and the group 3 elements in the second catalyst layer 30 promote the production of hydrocarbons by the reaction of CO2 and / or CO with the reducing gas in the gas G2. Therefore, in step (b), hydrocarbons can be produced. The space velocity of the gas G2 is, for example, 1 h -1 to 100,000 h -1 per hour or less, preferably 100 h -1 per hour or more and 50,000 h -1 per hour or less. The space velocity of the gas G2 is obtained by dividing the flow rate (m 3 h ―1 ) of the gas G2 by the volume (m 3 ) of the reaction chamber 41. The supply time of the gas G2 is, for example, 1 minute or more and 120 minutes or less, preferably 3 minutes or more and 60 minutes or less. The pressure in the reaction chamber 41 during CO2 release and hydrocarbon production is, for example, 0.05 MPa or more and 5 MPa or less, preferably 0.08 MPa or more and 0.2 MPa or less. When the temperature T2 is equal to or higher than the temperature T0 and lower than the temperature T1, the temperature of the catalyst 1 during CO2 release and hydrocarbon production is controlled to a temperature T31 that is equal to or higher than the temperature T2 and lower than the temperature T1. When the temperature T2 is lower than the temperature T0, the temperature is controlled to a temperature T32 that is equal to or higher than the temperature T0 and lower than the temperature T2. The temperature T31 is preferably 150°C or more and 500°C or less, more preferably 170°C or more and 450°C or less, and even more preferably 200°C or more and 400°C or less. The temperature T32 is preferably 150°C or more and 600°C or less, more preferably 170°C or more and 550°C or less, and even more preferably 200°C or more and 500°C or less. The heating rate of the catalyst 1 during heating is, for example, 1°C / min or more and 100°C / min or less, preferably 100°C / min or more and 350°C / min or less. The heating of the catalyst 1 can be carried out by the temperature control means 6. The supply of the gas G2 to the reaction chamber 41 can be carried out by the gas supply means 5. The gas G2 supplied to the reaction chamber 41 is discharged from the reaction chamber 41 through the gas outlet 43 of the reactor 4. The supply of the gas G2 to the reaction chamber 41 may be carried out continuously or intermittently, but it is preferably carried out continuously.

[0260] The hydrocarbon G4 produced in step (b) is discharged from the reaction chamber 41 through the gas outlet 43 of the reactor 4. The hydrocarbon G4 discharged from the reaction chamber 41 can be recovered through the discharge pipe 7.

[0261] Before the end of the reduction treatment and before the start of step (a), and / or after the end of step (a) and before the start of step (b), gas G3 may be supplied to the reaction chamber 41. Thereby, the reaction chamber 41 is purged with gas G3, and reaction inhibiting components (for example, O2, H2O, volatile organic substances) are removed from the reaction chamber 41. The purge time is, for example, 1 minute or more and 60 minutes or less, preferably 3 minutes or more and 30 minutes or less. The temperature of the catalyst 1 during purging is, for example, 0°C or more and 300°C or less, preferably 10°C or more and 200°C or less. The temperature control of the catalyst 1 can be carried out by the temperature control means 6. The supply of gas G3 to the reaction chamber 41 can be carried out by the gas supply means 5. The gas G3 supplied to the reaction chamber 41 is discharged from the reaction chamber 41 through the gas outlet 43 of the reactor 4. The supply of gas G3 to the reaction chamber 41 may be carried out continuously or intermittently.

[0262] In the hydrocarbon production method using System 100, the first catalyst layer 20 starts releasing CO2 adsorbed on the first catalyst layer 20 at temperature T0 and stops at temperature T1. The second catalyst layer 30 starts producing hydrocarbons at temperature T2. Therefore, by controlling the temperature in the same reaction chamber 41 where the first catalyst layer 20 and the second catalyst layer 30 are installed to a temperature of T2 or higher but less than T1 if temperature T2 is between T0 and T1, and to a temperature of T32 between T0 and T2 if temperature T2 is less than T0, the release of CO2 from the first catalyst layer 20 and the production of hydrocarbons by the second catalyst layer 30 can be achieved simultaneously. Since System 100, in which the first catalyst layer 20 and the second catalyst layer 30 are installed in the same reaction chamber 41, can be made space-saving, it is suitable for use in enclosed spaces such as spacecraft and space stations. The temperature T1 may change due to the influence of factors such as the amount of CO2 adsorbed on the first catalyst layer 20, the heating rate of the first catalyst layer 20, the pressure when the first catalyst layer 20 releases CO2, and the space velocity of the gas G2 flowing through the reaction chamber 41 when the first catalyst layer 20 releases CO2.

[0263] If temperature T2 is above temperature T1, the second catalyst layer 30 begins hydrocarbon production only after the release of CO2 from the first catalyst layer 20 is complete. Therefore, it is not possible to simultaneously achieve the release of CO2 from the first catalyst layer 20 and the production of hydrocarbons by the second catalyst layer 30. Consequently, when the first catalyst layer 20 and the second catalyst layer 30 are installed in the same reaction chamber 41, the reaction chamber 41 requires space to retain the CO2 released from the first catalyst layer 20 until the second catalyst layer 30 begins hydrocarbon production.

[0264] If a first catalyst layer 20 and a second catalyst layer 30 installed in the same reaction chamber 41 can simultaneously release CO2 from the first catalyst layer 20 and produce hydrocarbons from the second catalyst layer 30, space savings can be achieved, making it suitable for use in enclosed spaces such as spacecraft and space stations. [Examples]

[0265] In the following examples and comparative examples, commercially available alumina particles (average particle size: 80 μm) were used as the Al-based oxide, and commercially available ceria particles (average particle size: 10 μm) were used as the Ce-based oxide. The mass content of Al in the alumina particles, calculated as Al2O3, was approximately 100% by mass (>99.5% by mass). The mass content of Ce in the ceria particles, calculated as CeO2, was approximately 100% by mass (>99.5% by mass).

[0266] <Example 1A> (1) Na loading process Sodium carbonate, an aluminum oxide, and water were added to a mixing container and evaporated to dryness while stirring. The resulting dried powder was calcined at 500°C for 1 hour to obtain the first calcined product (Na-supported powder).

[0267] (2) Second group element loading process Rhodium nitrate and water were added to the first calcined product obtained in (1) above, and the mixture was evaporated to dryness while stirring. The resulting dried powder was calcined at 500°C for 1 hour to obtain a second calcined product (Na and Rh-supported powder). The obtained second calcined product was used as the CO2 recovery composition for Example 1A.

[0268] The amounts of each component in the second calcined product were adjusted based on the mass of the second calcined product so that Na was 30.0% by mass in terms of Na2O, Rh was 5.0% by mass in terms of metal, and Al was 65.0% by mass in terms of Al2O3.

[0269] <Example 2A> Except for using cobalt nitrate instead of rhodium nitrate, and adjusting the amounts of each component in the second calcined product so that Na was 30.0% by mass in terms of Na2O, Co was 5.0% by mass in terms of metal, and Al was 65.0% by mass in terms of Al2O3, based on the mass of the second calcined product, the same procedure as in Example 1A was carried out to obtain a second calcined product (Na and Co-supported powder). The obtained second calcined product was used as the CO2 recovery composition for Example 2A.

[0270] <Example 3A> Except for using nickel nitrate instead of rhodium nitrate, and adjusting the amounts of each component in the second calcined product so that Na was 30.0% by mass in terms of Na2O, Ni was 5.0% by mass in terms of metal, and Al was 65.0% by mass in terms of Al2O3, based on the mass of the second calcined product, the same procedure as in Example 1A was carried out to obtain a second calcined product (Na and Ni-supported powder). The obtained second calcined product was used as the CO2 recovery composition of Example 3A.

[0271] <Example 4A> Except for using an aqueous solution of dinitrodiammineplatinic acid instead of rhodium nitrate, and adjusting the amounts of each component in the second calcined product so that, based on the mass of the second calcined product, Na was 30.0% by mass in terms of Na2O, Pt was 5.0% by mass in terms of metal, and Al was 65.0% by mass in terms of Al2O3, the same procedure as in Example 1A was carried out to obtain a second calcined product (Na and Pt-supported powder). The obtained second calcined product was used as the CO2 recovery composition of Example 4A.

[0272] <Example 5A> Except for using palladium nitrate instead of rhodium nitrate, and adjusting the amounts of each component in the second calcined product so that Na was 30.0% by mass in terms of Na2O, Pd was 5.0% by mass in terms of metal, and Al was 65.0% by mass in terms of Al2O3, based on the mass of the second calcined product, the same procedure as in Example 1A was performed to obtain a second calcined product (Na and Pd-supported powder). The obtained second calcined product was used as the CO2 recovery composition of Example 5A.

[0273] <Comparative Example 1A> Except for not performing the second group element loading step and adjusting the amounts of each component in the first calcined product so that Na was 30.0% by mass in terms of Na2O and Al was 70.0% by mass in terms of Al2O3, based on the mass of the first calcined product, the same procedure as in Example 1A was performed to obtain the first calcined product (Na-supported powder). The obtained first calcined product was used as the CO2 recovery composition for Comparative Example 1A.

[0274] <Comparative example 2A> The point of using copper nitrate instead of rhodium nitrate, and except for the point of adjusting the amounts of each component of the second fired product so that, based on the mass of the second fired product, Na is 30.0% by mass in terms of Na2O, Cu is 5.0% by mass in terms of metal, and Al is 65.0% by mass in terms of Al2O3, the same operations as in Example 1A were carried out to obtain a second fired product (Na and Cu supported powder). The obtained second fired product was used as the CO2 recovery composition of Comparative Example 2A.

[0275] <Comparative Example 3A> The point of using manganese(II) nitrate instead of rhodium nitrate, and except for the point of adjusting the amounts of each component of the second fired product so that, based on the mass of the second fired product, Na is 30.0% by mass in terms of Na2O, Mn is 5.0% by mass in terms of metal, and Al is 65.0% by mass in terms of Al2O3, the same operations as in Example 1A were carried out to obtain a second fired product (Na and Mn supported powder). The obtained second fired product was used as the CO2 recovery composition of Comparative Example 3A.

[0276] <Comparative Example 4A> The point of using ruthenium nitrate instead of rhodium nitrate, and except for the point of adjusting the amounts of each component of the second fired product so that, based on the mass of the second fired product, Na is 30.0% by mass in terms of Na2O, Ru is 5.0% by mass in terms of metal, and Al is 65.0% by mass in terms of Al2O3, the same operations as in Example 1A were carried out to obtain a second fired product (Na and Ru supported powder). The obtained second fired product was used as the CO2 recovery composition of Comparative Example 4A.

[0277] <Comparative Example 5A> The point of using silver nitrate instead of rhodium nitrate, and except for the point of adjusting the amounts of each component of the second fired product so that, based on the mass of the second fired product, Na is 30.0% by mass in terms of Na2O, Ag is 5.0% by mass in terms of metal, and Al is 65.0% by mass in terms of Al2O3, the same operations as in Example 1A were carried out to obtain a second fired product (Na and Ag supported powder). The obtained second fired product was used as the CO2 recovery composition of Comparative Example 5A.

[0278] <Test Example 1A> CO2 adsorption capacity evaluation tests were conducted on each CO2 recovery composition for Examples 1A to 5A and Comparative Examples 1A to 5A. 20 mg of each composition was weighed and placed in a thermal analyzer (NETZSCH TG-DTA200SA). Pretreatment (reduction treatment) was performed by passing a gas consisting of H2: 4 vol% and He: the remainder at 350°C for 10 minutes. Subsequently, the temperature was lowered to 150°C while passing a gas consisting of N2: 100 vol% through the analyzer. Then, CO2 adsorption treatment was performed by passing a gas consisting of CO2: 100 vol% through the analyzer at 150°C for 45 minutes. The amount of CO2 adsorbed per unit mass of the composition (mmol / g) was measured from the mass difference of the composition before and after CO2 gas introduction. The results are shown in Table 1.

[0279] The significance of R1 to R4 in Table 1 is as follows: R1: The ratio of the oxide-equivalent mass of the Group 1 elements to the sum of the oxide-equivalent mass of the Group 1 elements and the metallic-equivalent mass of the Group 2 elements. R2: The ratio of the metallic mass of the Group 2 elements to the sum of the oxide mass of the Group 1 elements and the metallic mass of the Group 2 elements. R3: The ratio of the mass of Al (in terms of Al2O3) to the sum of the masses of the first group elements (in terms of oxides) and the second group elements (in terms of metals). R4: The ratio of the sum of the mass of Al (as Al2O3), the mass of the Group 1 elements (as oxides), and the mass of the Group 2 elements (as metals) to the mass of the composition.

[0280] [Table 1]

[0281] <Example 1B> Except for using an aqueous solution of dinitrodiammineplatinic acid instead of rhodium nitrate, and adjusting the amounts of each component in the second calcined product so that, based on the mass of the second calcined product, Na was 9.7% by mass in terms of Na2O, Pt was 3.0% by mass in terms of metal, and Al was 87.3% by mass in terms of Al2O3, the same procedure as in Example 1A was carried out to obtain a second calcined product (Na and Pt-supported powder). The obtained second calcined product was used as the CO2 recovery composition of Example 1B.

[0282] <Example 2B> Except for using potassium carbonate instead of sodium carbonate, and adjusting the amounts of each component in the second calcined product so that, based on the mass of the second calcined product, K was 9.7% by mass in terms of K2O, Pt was 3.0% by mass in terms of metal, and Al was 87.3% by mass in terms of Al2O3, the same procedure as in Example 1B was carried out to obtain the second calcined product (K and Pt-supported powder). The obtained second calcined product was used as the CO2 recovery composition for Example 2B.

[0283] <Example 3B> The same procedure as in Example 1B was followed to obtain a second calcined product (Na and Pt-supported powder), except that the amounts of each component in the second calcined product were adjusted so that, based on the mass of the second calcined product, Na was 14.6% by mass in terms of Na2O, Pt was 3.0% by mass in terms of metal, and Al was 82.4% by mass in terms of Al2O3. The obtained second calcined product was used as the CO2 recovery composition for Example 3B.

[0284] <Example 4B> Except for using cobalt nitrate instead of dinitrodiammineplatinic acid aqueous solution, and adjusting the amounts of each component in the second calcined product so that, based on the mass of the second calcined product, K was 9.7% by mass in terms of K2O, Co was 3.0% by mass in terms of metal, and Al was 87.3% by mass in terms of Al2O3, the same procedure as in Example 2B was carried out to obtain the second calcined product (K and Co-supported powder). The obtained second calcined product was used as the CO2 recovery composition of Example 4B.

[0285] <Example 5B> Except for using cobalt nitrate instead of dinitrodiammineplatinic acid aqueous solution, and adjusting the amounts of each component in the second calcined product so that Na was 9.7% by mass in terms of Na2O, Co was 3.0% by mass in terms of metal, and Al was 87.3% by mass in terms of Al2O3, based on the mass of the second calcined product, the same procedure as in Example 1B was performed to obtain a second calcined product (Na and Co-supported powder). The obtained second calcined product was used as the CO2 recovery composition for Example 5B.

[0286] <Comparative example 1B> The same procedure as in Example 1B was followed to obtain a second calcined product (Na and Pt-supported powder), except that the amounts of each component in the second calcined product were adjusted so that, based on the mass of the second calcined product, Na was 19.4% by mass in terms of Na2O, Pt was 3.0% by mass in terms of metal, and Al was 77.6% by mass in terms of Al2O3. The obtained second calcined product was used as the CO2 recovery composition for Comparative Example 1B.

[0287] <Comparative Example 2B> The same procedure as in Example 4B was followed to obtain a second calcined product (K and Co-supported powder), except that the amounts of each component in the second calcined product were adjusted so that, based on the mass of the second calcined product, K was 19.4% by mass in terms of K2O, Co was 3.0% by mass in terms of metal, and Al was 77.6% by mass in terms of Al2O3. The obtained second calcined product was used as the CO2 recovery composition for Comparative Example 2B.

[0288] <Comparative example 3B> Except for not performing the element loading step for the second group of elements, and adjusting the amounts of each component in the first calcined product so that Na was 10.0% by mass in terms of Na2O and Al was 90.0% by mass in terms of Al2O3, based on the mass of the first calcined product, the same procedure as in Example 1B was performed to obtain the first calcined product (Na-supported powder). The obtained first calcined product was used as the CO2 recovery composition for Comparative Example 3B.

[0289] <Comparative example 4B> Except for using potassium carbonate instead of sodium carbonate, and adjusting the amounts of each component in the first calcined product so that K was 10.0% by mass in terms of K2O and Al was 90.0% by mass in terms of Al2O3, based on the mass of the first calcined product, the same procedure as in Comparative Example 3B was performed to obtain the first calcined product (K-supported powder). The obtained first calcined product was used as the CO2 recovery composition for Comparative Example 4B.

[0290] <Comparative Example 5B> Except for using calcium nitrate instead of sodium carbonate, and adjusting the amounts of each component in the second calcined product so that, based on the mass of the second calcined product, Ca was 9.7% by mass in terms of CaO, Pt was 3% by mass in terms of metal, and Al was 87.3% by mass in terms of Al2O3, the same procedure as in Example 1B was carried out to obtain a second calcined product (Ca and Pt-supported powder). The obtained second calcined product was used as the CO2 recovery composition for Comparative Example 5B.

[0291] <Comparative Example 6B> Except for using cobalt nitrate instead of dinitrodiammineplatinic acid aqueous solution, and adjusting the amounts of each component in the second calcined product so that Ca was 9.7% by mass in terms of CaO, Co was 3% by mass in terms of metal, and Al was 87.3% by mass in terms of Al2O3, based on the mass of the second calcined product, the same procedure as in Comparative Example 5B was performed to obtain the second calcined product (Ca and Co-supported powder). The obtained second calcined product was used as the CO2 recovery composition for Comparative Example 6B.

[0292] <Comparative example 7B> Except for using calcium nitrate instead of sodium carbonate, and adjusting the amounts of each component in the first calcined product so that Ca was 10.0% by mass in terms of CaO and Al was 90.0% by mass in terms of Al2O3, based on the mass of the first calcined product, the same procedure as in Comparative Example 3B was performed to obtain the first calcined product (Ca-supported powder). The obtained first calcined product was used as the CO2 recovery composition for Comparative Example 7B.

[0293] <Comparative Example 8B> In a mixing container, an aqueous solution of dinitrodiammineplatinic acid, an Al-based oxide, and water were added and evaporated to dryness while stirring. The resulting dried powder was calcined at 500°C for 1 hour to obtain a calcined product (Pt-supported powder). The obtained calcined product was used as the CO2 recovery composition for Comparative Example 8B. The amounts of each component in the calcined product were adjusted so that Pt was 3.0% by mass in terms of metal equivalent and Al was 97.0% by mass in terms of Al2O3, based on the mass of the calcined product.

[0294] <Comparative example 9B> Except for using cobalt nitrate instead of dinitrodiammineplatinic acid aqueous solution, and adjusting the amounts of each component in the calcined product so that Co was 3.0% by mass in terms of metallic equivalent and Al was 97.0% by mass in terms of Al2O3, based on the mass of the calcined product, the same procedure as in Comparative Example 8B was performed to obtain a calcined product (Co-supported powder). The obtained calcined product was used as the CO2 recovery composition for Comparative Example 9B.

[0295] <Comparative example 10B> Al-based oxides that had not undergone either the Group 1 element loading process or the Group 2 element loading process were used as the CO2 recovery composition for Comparative Example 10B.

[0296] <Test Example 1B> CO2 adsorption capacity evaluation tests were conducted on each CO2 recovery composition in Examples 1B to 5B and Comparative Examples 1B to 10B in the same manner as in Test Example 1A. The results are shown in Table 2. The meanings of R1 to R4 in Table 2 are the same as in Table 1.

[0297] [Table 2]

[0298] <Example 1C> (1) Preparation of compositions for hydrocarbon production Ruthenium nitrate and Ce-based oxides were added to a mixing container and stirred for 1 hour. Then, a sufficient amount of 28% aqueous ammonia was added and stirred for 5 minutes. After that, the mixture was filtered through a membrane filter, and the filtrate was repeatedly washed with pure water and then dried. The resulting dried powder was calcined at 500°C for 1 hour to obtain a calcined product (Ru-supported powder). 92 parts by mass of the obtained calcined product and 8 parts by mass (in terms of solid content) of alumina sol as a binder were mixed to obtain the hydrocarbon production composition of Example 1C.

[0299] The amounts of each component in the calcined product were adjusted based on the mass of the calcined product so that Ru was 0.36 mass% in metallic terms and Ce was 99.64 mass% in CeO2 terms.

[0300] (2) Preparation of the hydrocarbon production section A slurry was prepared by mixing the hydrocarbon production composition of Example 1C with water.

[0301] As a substrate, a flow-through type substrate was prepared, having axially extending cells partitioned by partitions with a thickness of 50-70 μm, with a density of 900 cells / square inch in a plane perpendicular to the axial direction, an axial length of 30 mm, and a volume of 0.015 L.

[0302] The entire length of a flow-through substrate was immersed in a slurry, the slurry-coated flow-through substrate was dried at 150°C for 0.5 hours, and then calcined at 500°C for 1 hour to obtain a catalyst (hydrocarbon production section of Example 1C) in which a catalyst layer made of the hydrocarbon production composition of Example 1C was formed on the partition wall of the flow-through substrate. The mass of the catalyst layer per unit volume of the portion of the flow-through substrate in which the catalyst layer was formed was 150 g / L.

[0303] <Example 2C> Except for using nickel acetate instead of ruthenium nitrate, and adjusting the amounts of each component in the calcined product so that Ni was 11.3% by mass in terms of metal equivalent and Ce was 88.7% by mass in terms of CeO2, the same procedure as in Example 1C (1) was carried out to obtain a calcined product (Ni-supported powder). Then, 92 parts by mass of the obtained calcined product and 8 parts by mass (in terms of solid content) of alumina sol as a binder were mixed to obtain the hydrocarbon production composition of Example 2C.

[0304] The hydrocarbon production section of Example 2C was obtained by performing the same procedure as in (2) of Example 1C, except that the hydrocarbon production composition of Example 2C was used instead of the hydrocarbon production composition of Example 1C.

[0305] <Comparative example 1C> Except for using an Al oxide instead of a Ce oxide, and adjusting the amounts of each component in the calcined product so that Ru was 0.36% by mass in terms of metal and Al was 99.64% by mass in terms of Al2O3, the same procedure as in Example 1C (1) was carried out to obtain a calcined product (Ru-supported powder). Then, 92 parts by mass of the obtained calcined product and 8 parts by mass (in terms of solid content) of alumina sol as a binder were mixed to obtain the hydrocarbon production composition of Comparative Example 1C.

[0306] The hydrocarbon production section of Comparative Example 1C was obtained by performing the same procedure as in (2) of Example 1C, except that the hydrocarbon production composition of Comparative Example 1C was used instead of the hydrocarbon production composition of Example 1C.

[0307] <Comparative Example 2C> Except for using nickel acetate instead of ruthenium nitrate, using Al oxide instead of Ce oxide, and adjusting the amounts of each component in the calcined product so that Ni was 11.3% by mass in terms of metal and Al was 88.7% by mass in terms of Al2O3, the same procedure as in Example 1C (1) was carried out to obtain a calcined product (Ni-supported powder). Then, 92 parts by mass of the obtained calcined product and 8 parts by mass (in terms of solid content) of alumina sol as a binder were mixed to obtain the hydrocarbon production composition of Comparative Example 2C.

[0308] The hydrocarbon production section of Comparative Example 2C was obtained by performing the same procedure as in (2) of Example 1C, except that the hydrocarbon production composition of Comparative Example 2C was used instead of the hydrocarbon production composition of Example 1C.

[0309] Table 3 shows the compositions of each hydrocarbon production composition for Examples 1C-2C and Comparative Examples 1C-2C.

[0310] The significance of R5 and R6 in Table 3 is as follows: R5: The ratio of the mass of Ce (in terms of CeO2) to the mass of the third group element (in terms of metal). R6: The ratio of the sum of the mass of Ce (calculated as CeO2) and the mass of the third group element (calculated as metal) to the mass of the composition.

[0311] [Table 3]

[0312] <Test Example 1C> Methane production amount evaluation tests were conducted for each production section of Examples 1C-2C and Comparative Examples 1C-2C. After setting the production section in a catalyst evaluation device (MEXA-ONE, HORIBA), pretreatment (reduction treatment) was performed by circulating a gas consisting of H2: 2 vol% and N2: remainder at 500°C for 10 minutes. Subsequently, the temperature was lowered to 150°C while circulating a gas consisting of N2: 100 vol%. Then, while circulating a reaction gas consisting of H2: 3.6 vol%, CO2: 0.72 vol%, CO: 0.18 vol%, and remainder: N2, the temperature of the production section was raised from 150°C to 500°C at a heating rate of 20°C / min. When the temperature reached 400°C, the amount of methane (ppm) flowing out from the outlet of the reaction tube was detected by a detector attached to the catalyst evaluation device, and this was defined as the methane production amount (ppm). The results are shown in Table 4.

[0313] [Table 4]

[0314] <Example 1D> The same procedure as in Example 1B was followed to obtain a second calcined product (Na and Pt-supported powder), except that the amounts of each component in the second calcined product were adjusted so that, based on the mass of the second calcined product, Na was 9.4% by mass in terms of Na2O, Pt was 6.0% by mass in terms of metal, and Al was 84.6% by mass in terms of Al2O3. 92 parts by mass of the obtained second calcined product and 8 parts by mass (in terms of solid content) of alumina sol as a binder were mixed to obtain the CO2 recovery composition of Example 1D.

[0315] The CO2 recovery unit of Example 1D was obtained by performing the same procedure as in (2) of Example 1C, except that the CO2 recovery composition of Example 1D was used instead of the hydrocarbon production composition of Example 1C.

[0316] <Example 2D> The same procedure as in Example 4B was followed to obtain the second calcined product (K and Co-supported powder), except that the amounts of each component in the second calcined product were adjusted so that, based on the mass of the second calcined product, K was 9.4% by mass in terms of K2O, Co was 6.0% by mass in terms of metal, and Al was 84.6% by mass in terms of Al2O3. 92 parts by mass of the obtained second calcined product and 8 parts by mass (in terms of solid content) of alumina sol as a binder were mixed to obtain the CO2 recovery composition of Example 2D.

[0317] The CO2 recovery section of Example 2D was obtained by performing the same procedure as in (2) of Example 1C, except that the CO2 recovery composition of Example 2D was used instead of the hydrocarbon production composition of Example 1C.

[0318] <Example 3D> 92 parts by mass of the second calcined product obtained in Example 4B and 8 parts by mass (based on solid content) of alumina sol as a binder were mixed to obtain the CO2 recovery composition of Example 3D.

[0319] The CO2 recovery unit of Example 3D was obtained by performing the same procedure as in (2) of Example 1C, except that the CO2 recovery composition of Example 3D was used instead of the hydrocarbon production composition of Example 1C.

[0320] Table 5 shows the compositions of each CO2 recovery composition for Examples 1D to 3D.

[0321] The significance of R1 to R3 in Table 5 is the same as in Table 1, and the significance of R4 is as follows: R4: The ratio of the sum of the mass of Al (as Al2O3), the mass of the Group 1 elements (as oxides), and the mass of the Group 2 elements (as metals) to the mass of the composition.

[0322] [Table 5]

[0323] <Test Example 1D> A hydrocarbon production catalyst, consisting of the CO2 recovery section of Example 1D and the hydrocarbon production section of Example 2C, was set up in a catalyst evaluation device (MEXA-ONE, manufactured by HORIBA) with the CO2 recovery section of Example 1D on the upstream side in the gas flow direction and the hydrocarbon production section of Example 2C on the downstream side. A pretreatment (reduction treatment) was then performed by flowing a gas consisting of 2 vol% H2 and the remainder N2 at 500°C for 10 minutes. Subsequently, the temperature was lowered to 150°C while flowing a gas consisting of 100 vol% N2. CO2 adsorption treatment was then performed by flowing a gas consisting of 8 vol% CO2 and the remainder N2 at 150°C for 10 minutes. Finally, N2 gas purging was performed by flowing a gas consisting of 100 vol% N2 at 150°C for 10 minutes. Subsequently, the catalyst was heated from 150°C to 500°C at a rate of 20°C / min while a reaction gas consisting of 2 vol% H2 and the remainder N2 was circulated. The cumulative amount of methane (mmol) flowing out of the outlet of the reaction tube between 150°C and 400°C was detected by a detector attached to the catalyst analyzer, and this was defined as the amount of methane produced (mmol). The results are shown in Table 6.

[0324] <Test Example 2D> The amount of methane produced was evaluated in the same manner as in Test Example 1D, except that the hydrocarbon production unit of Example 1C was used instead of the hydrocarbon production unit of Example 2C. The results are shown in Table 6.

[0325] <Test Example 3D> The amount of methane produced was evaluated in the same manner as in Test Example 1D, except that the CO2 recovery unit of Example 2D was used instead of the CO2 recovery unit of Example 1D. The results are shown in Table 6.

[0326] <Test Example 4D> The amount of methane produced was evaluated in the same manner as in Test Example 1D, except that the CO2 recovery unit of Example 3D was used instead of the CO2 recovery unit of Example 1D. The results are shown in Table 6.

[0327] <Test Example 5D> Except for using the CO2 recovery unit of Example 3D instead of the CO2 recovery unit of Example 1D, and using the hydrocarbon production unit of Example 1C instead of the hydrocarbon production unit of Example 2C, the amount of methane produced was evaluated in the same manner as in Test Example 1D. The results are shown in Table 6.

[0328] [Table 6] [Explanation of symbols]

[0329] 100...Hydrogen production system 4. Reactor 41. Reaction Chamber 42...Gas inlet 43...Gas outlet 5. Gas supply means 50...Gas supply pipe 51...First gas supply source 52...Second gas supply source 53. Third gas supply source 6. Temperature control means 7...Discharge pipe G1, G2, G3... Gas G4...Hydrogen 1,1A,1B... Catalysts for hydrocarbon production 10...Base material 10a...First base material part 10b...Second base material part 11a, 11b... tubular part 12a,12b...Bulkhead part 13a, 13b... cells 20...1st catalyst layer 30...Second catalyst layer L10a...Length of the first base material L10b...Length of the second base material L20...Average length of the first catalyst layer L30...Average length of the second catalyst layer

Claims

1. CO2 contains Al, one or more elements selected from alkali metal elements (hereinafter referred to as "Group 1 elements"), and one or more elements selected from Co, Ni, Rh, Pd, and Pt (hereinafter referred to as "Group 2 elements"). ２ A composition for recovery, The following formula (1): 1.5 ≤ R1 / R2 ≤ 6 ... (1) [In the formula, R1 represents the ratio of the oxide-equivalent mass of the first group element in the composition to the sum of the oxide-equivalent mass of the first group element and the metallic-equivalent mass of the second group element, and R2 represents the ratio of the metallic-equivalent mass of the second group element in the composition to the sum of the oxide-equivalent mass of the first group element and the metallic-equivalent mass of the second group element.] The composition that satisfies the requirements.

2. The composition according to claim 1, wherein R1 is 0.2 or more and 0.86 or less.

3. The above composition is of the following formula (2): 1 ≤ R3 ... (2) [In the formula, R3 is the Al of A1 in the composition.] ２ O ３ This represents the ratio of the converted mass to the sum of the oxide-based mass of the first group element and the metallic-based mass of the second group element. The composition according to claim 1, which satisfies the requirements.

4. The composition according to claim 1, wherein the first group of elements is composed of one or more elements selected from Na and K.

5. The composition according to claim 1, wherein the second group of elements is composed of one or more elements selected from Pt and Co.

6. The composition according to claim 1, wherein the first group element is composed of Na and the second group element is composed of Pt, or the first group element is composed of K and the second group element is composed of Co.

7. The composition according to claim 6, wherein the first group element is composed of Na and the second group element is composed of Pt.

8. The composition according to claim 1, wherein the composition comprises an Al-based oxide, and at least a portion of the first group elements and at least a portion of the second group elements are supported on the Al-based oxide.

9. A catalyst for hydrocarbon production comprising a first composition and a second composition, The first composition comprises the composition described in any one of claims 1 to 8, The second composition comprises Ce and CO ２ The catalyst comprises one or more elements (hereinafter referred to as "third group elements") that have the effect of reducing CO to produce hydrocarbons.

10. The catalyst according to claim 9, wherein the third group element is composed of one or more elements selected from Ni and Ru.

11. The catalyst according to claim 10, wherein the third group element is composed of Ni.

12. The catalyst according to claim 9, wherein the second composition comprises a Ce-based oxide, and at least a portion of the third group element is supported on the Ce-based oxide.

13. The catalyst comprises a substrate having a first substrate portion and a second substrate portion, a first catalyst layer provided on the first substrate portion, and a second catalyst layer provided on the second substrate portion. The first catalyst layer comprises the first composition, The catalyst according to claim 9, wherein the second catalyst layer comprises the second composition.

14. A hydrocarbon production system comprising a reaction chamber and a catalyst according to claim 9 housed in the reaction chamber.

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