Reactor

Abstract

Provided is a reactor capable of efficiently producing a desired reaction product. A reactor according to one embodiment of the present invention has a gas flow path. To the gas flow path, a raw material gas containing carbon oxide and hydrogen is supplied. The reactor is provided with a ceramic base material and a catalyst layer. The catalyst layer is disposed on a surface of the ceramic base material in a state of facing the gas flow path. The catalyst layer contains a methanation reaction catalyst capable of promoting a reaction for generating methane. The ceramic base material has a thermal conductivity of 8 W / m·K or more. The catalyst layer has a porosity of 20% or more.

Description

reactor

[0001] This invention relates to a reactor.

[0002] In recent years, from the perspective of reducing environmental impact, the recovery of carbon monoxide and its reuse as a raw material for carbon compounds has been considered. For example, a method has been proposed for producing methane in which a raw material gas containing hydrogen gas, oxygen gas, and carbon dioxide gas is supplied to a reactor equipped with a catalyst, and the methanation reaction is started and continued by the heat, including the reaction heat from the catalytic combustion of hydrogen gas (see, for example, Patent Document 1). In addition, a method for synthesizing lower isoparaffins has also been proposed, for example, which involves contacting the synthesis gas of hydrogen and carbon monoxide with a Fischer-Tropsch synthesis catalyst mixed with a solid acid catalyst that mainly hydrocracking long-chain hydrocarbons to synthesize linear hydrocarbons (see, for example, Patent Document 2).

[0003] International Publication No. 2021 / 045101, Japanese Patent Publication No. 2001-288123

[0004] However, the method for producing methane described in Patent Document 1 may result in an insufficient methane yield. Furthermore, the method for synthesizing lower isoparaffins described in Patent Document 2 may result in an insufficient yield of the liquid fuel component with 5 to 20 carbon atoms in the resulting hydrocarbon. In particular, a problem arises when the processing rate of the raw material gas per unit volume in the reactor (space velocity SV) increases, leading to a significant decrease in the yield of the desired reaction product. Therefore, improving the yield of the desired reaction product is increasingly desirable in these various chemical reactions. The main objective of the present invention is to provide a reactor capable of efficiently producing the desired reaction product.

[0005] [1] A reactor according to one embodiment of the present invention has a gas channel. A raw material gas containing reactants is supplied to the gas channel. The reactor comprises a ceramic substrate and a catalyst layer. The catalyst layer is disposed on the surface of the ceramic substrate so as to face the gas channel. The catalyst layer contains a catalyst capable of promoting the chemical reaction of the reactants. The thermal conductivity of the ceramic substrate is 8 W / m·K or more. The porosity of the catalyst layer is 20% or more. [2] In the reactor described in [1] above, the porosity of the catalyst layer may be 75% or less. [3] In the reactor described in [1] or [2] above, the porosity of the catalyst layer may be 25% or more. [4] In the reactor described in any of [1] to [3] above, the thickness of the catalyst layer may be 0.1 μm or more and 500 μm or less. [5] In the reactor described in any of [1] to [4] above, the thickness of the catalyst layer may be less than 300 μm. [6] In the reactor described in any of [1] to [5] above, the thickness of the catalyst layer may exceed 20 μm. [7] In the reactor described in any of [1] to [6] above, the thermal conductivity of the ceramic substrate may be 100 W / m·K or more. [8] In the reactor described in any of [1] to [7] above, the porosity of the ceramic substrate may be 65% or less. The average pore diameter of the ceramic substrate may be 50 μm or less. [9] In the reactor described in any of [1] to [8] above, the ceramic substrate may be a honeycomb-shaped substrate having partitions that constitute a plurality of cells. At least a portion of the plurality of cells includes the gas flow path.

[10] In the reactor described in [9] above, the thickness of the partitions may exceed 0.254 mm.

[11] In the reactor described in any of [1] to [8] above, the reactants may include carbon oxide and hydrogen.

[12] In the reactor described in

[11] above, the raw material gas may further contain oxygen.

[13] In the reactor described in

[11] or

[12] above, the catalyst may be a methane reaction catalyst.

[14] In the reactor described in

[11] or

[12] above, the catalyst may be a Fischer-Tropsch reaction catalyst.

[15] In the reactor described in any of [1] to

[14] above, the ceramic substrate may contain Si and SiC.

[16] In the reactor described in any of [1] to

[15] above, the catalyst may contain a transition metal as an active component.

[17] In the reactor described in

[16] above, the transition metal may include Co, Fe, Pt, Ru, Rh, Pd, Ni, Cu, Ag, Au, Ir, Os, Mn, Ta, Mo, Zn, Cr, or a combination thereof.

[18] In the reactor described in

[16] or

[17] above, the catalyst may further contain a carrier supporting the transition metal. The carrier may contain cerium oxide, silicon oxide, zirconium oxide, yttrium oxide, aluminum oxide, magnesium oxide, titanium oxide, or a combination of these oxides.

[0006] According to embodiments of the present invention, desired reaction products can be efficiently produced.

[0007] Figure 1 is a schematic perspective view of a reactor according to one embodiment of the present invention. Figure 2 is a schematic cross-sectional view of the reactor in Figure 1.

[0008] Embodiments of the present invention will be described below with reference to the drawings, but the present invention is not limited to these embodiments. Furthermore, in order to clarify the explanation, the drawings may schematically represent the width, thickness, shape, etc., of each part compared to the embodiments; however, these are merely examples and do not limit the interpretation of the present invention.

[0009] A. Diagram 1 of the reactor is a schematic perspective view of a reactor according to one embodiment of the present invention; Figure 2 is a schematic cross-sectional view of the reactor of Figure 1. The reactor 100 typically has a gas channel 15. The reactor 100 comprises a ceramic substrate 1 and a catalyst layer 2. The catalyst layer 2 contains a catalyst capable of promoting a desired chemical reaction. The catalyst layer 2 is positioned on the surface of the ceramic substrate 1 so as to face the gas channel 15. A raw material gas containing reactants is supplied to the gas channel 15 of the reactor 100. The reactants typically include carbon oxide (typically carbon dioxide and / or carbon monoxide) and hydrogen. In one embodiment, the catalyst is a methanation catalyst capable of promoting a reaction that produces methane (hereinafter referred to as the methanation reaction). In another embodiment, it is an FT reaction catalyst capable of promoting the Fischer-Tropsch reaction (hereinafter sometimes referred to as the FT reaction). Furthermore, the catalyst may also be capable of promoting a reaction that produces alcohol. When the raw material gas is supplied to the gas flow path 15, if the catalyst is a methanation catalyst, the methanation reaction shown in equation (I) and / or equation (II) below will typically proceed in the reactor 100.

[0010] Furthermore, if the catalyst is an FT reaction catalyst, typically at least one of the FT reactions shown in formulas (III) to (VI) below will proceed in reactor 100.

[0011] Furthermore, in reactor 100, the alcohol production reaction shown in formula (VII) and / or formula (VIII) below may typically proceed. In this specification, hydrocarbons include not only organic compounds composed only of carbon and hydrogen, but also alcohol compounds containing carbon, hydrogen, and oxygen. Since these chemical reactions (especially the methanation reaction and the FT reaction) are exothermic reactions, reaction heat is generated as the chemical reaction (especially the methanation reaction) progresses.

[0012] Furthermore, catalysts such as dry reforming catalysts and ammonia decomposition catalysts can also be used.

[0013] In one embodiment, the porosity of the catalyst layer 2 is 20% or more, and the thermal conductivity of the ceramic substrate 1 is 8 W / m·K or more. The inventors discovered that when the processing rate of raw material gas per unit volume in the reactor (hereinafter sometimes referred to as space velocity SV) increases, the diffusion of the raw material gas into the catalyst layer becomes insufficient, and the yield of the reaction product decreases. Therefore, the inventors investigated increasing the porosity of the catalyst layer to promote the diffusion of the raw material gas in the catalyst layer, but found it difficult to control the porosity of the catalyst layer to 20% or more. Therefore, the inventors diligently investigated how to improve the porosity of the catalyst layer and found that by devising ways to adjust the porosity of the pore-forming material used in the formation of the catalyst layer and the particle size of the catalyst particles, various parameters in the catalyst layer (e.g., porosity) can be controlled with high precision. Furthermore, it was confirmed that when the porosity of the catalyst layer is increased, the thermal conductivity of the catalyst layer decreases, and the reaction heat generated by the chemical reaction is not dissipated from the catalyst layer, causing the catalyst layer to be partially excessively heated. As a result, when the temperature of the catalyst layer reaches a high temperature range, for example, exceeding 600°C, the reaction yield (e.g., the yield of hydrocarbons such as methane) may decrease due to equilibrium limitations of the chemical reaction (e.g., methanation reaction, FT reaction) and / or degradation (sintering) of the catalyst (e.g., methanation reaction catalyst, FT reaction catalyst). As described above, the inventors had obtained knowledge that allowed them to accurately control various parameters in the catalyst layer, and were able to adjust the configuration of the catalyst layer to investigate how to achieve both gas diffusivity and thermal diffusivity. As a result, they found that by adjusting the porosity of the catalyst layer and the thermal conductivity of the ceramic substrate, they could achieve a good balance between gas diffusivity and thermal diffusivity in the catalyst layer and stably improve the reaction yield (e.g., the yield of hydrocarbons such as methane). More specifically, since the porosity of the catalyst layer facing the gas channel is 20% or more, the gas diffusivity in the catalyst layer can be improved. Therefore, even if the space velocity SV of the raw material gas supplied to the gas channel exceeds a predetermined value, the raw material gas can be sufficiently diffused into the catalyst layer. The lower limit of the space velocity SV of the raw material gas is set appropriately according to the chemical reaction proceeding in the reactor.When a methanation reaction proceeds in the reactor, the raw material gas can be sufficiently diffused into the catalyst layer even if the space velocity SV of the raw material gas is, for example, 3000 / h or more. Similarly, when a FT reaction proceeds in the reactor, the raw material gas can be sufficiently diffused into the catalyst layer even if the space velocity SV of the raw material gas is, for example, 750 / h or more. Furthermore, since the thermal conductivity of the ceramic substrate supporting the catalyst layer is 8 W / m·K or higher, the reaction heat generated by the chemical reaction (e.g., methanation reaction, FT reaction) is smoothly transferred from the catalyst layer to the ceramic substrate, uniformly heating the entire catalyst layer through the ceramic substrate. As a result, the catalyst layer can be stably controlled to a temperature suitable for the desired chemical reaction (e.g., methanation reaction, FT reaction) (e.g., around 200°C to 300°C). These features allow for a stable improvement in reaction yield (e.g., yield of hydrocarbons such as methane), enabling the production of desired reaction products (e.g., hydrocarbons such as methane) in an energy-efficient manner. In particular, even when the space velocity SV of the raw material gas supplied to the gas flow path is relatively large, the reactor can achieve excellent reaction yields (e.g., yield of hydrocarbons such as methane). Furthermore, since thermal degradation of the reactor (ceramic substrate and / or catalyst) can be suppressed, the lifespan of the reactor can be extended and the maintainability of the reactor can be improved.

[0014] The thermal conductivity of the ceramic substrate 1 is preferably 10 W / m·K or higher, more preferably 50 W / m·K or higher, even more preferably 100 W / m·K or higher, and particularly preferably 120 W / m·K or higher. When the thermal conductivity of the ceramic substrate is above this lower limit, the reaction heat generated by the chemical reaction (e.g., methanation reaction, FT reaction) is rapidly diffused from the catalyst layer to the ceramic substrate, improving the uniformity of the catalyst layer. As a result, the temperature can be appropriately controlled throughout the gas flow path, and the chemical reaction (e.g., methanation reaction, FT reaction) can proceed with excellent reaction yield (e.g., hydrocarbon production yield such as methane). On the other hand, the upper limit of the thermal conductivity of the ceramic substrate 1 is not limited, but is typically 1000 W / m·K. The thermal conductivity is calculated, for example, by preparing a sample of a predetermined size from the object, measuring the thermal diffusivity of the sample using an optical AC thermal diffusivity measuring device (typically Laser-PIT), measuring the specific heat of the sample using differential scanning calorimetry (DSC), and measuring the bulk density of the sample using Archimedes density measurement, based on the following formula (1): Thermal conductivity = Thermal diffusivity × Specific heat × Bulk density ... (1)

[0015] The thermal diffusivity of the ceramic substrate 1 is, for example, 1.0 × 10⁻⁶ －５ I understand ２ / s ~ 10 x 10 －５ I understand ２ The temperature is / s. The specific heat of the ceramic substrate 1 is, for example, 600 J / (kg·K) to 750 J / (kg·K). The bulk density of the ceramic substrate 1 is, for example, 1.0 g / mL to 3.0 g / mL.

[0016] The porosity of the ceramic substrate 1 is appropriately set according to the purpose. For example, the porosity of the ceramic substrate 1 is 70% or less, preferably 65% ​​or less, and more preferably 50% or less. On the other hand, the porosity of the ceramic substrate 1 is, for example, 0% or more, and also, for example, 0.1% or more. When the porosity of the ceramic substrate is within such a range, the thermal conductivity of the ceramic substrate can be stably adjusted to the above range. The porosity is measured, for example, by the mercury intrusion method.

[0017] When the porosity of the ceramic substrate 1 exceeds 0%, the average pore diameter of the ceramic substrate 1 is, for example, 60 µm or less, preferably 50 µm or less, more preferably 30 µm or less, and still more preferably 20 µm or less. On the other hand, the average pore diameter of the ceramic substrate 1 is, for example, 1 µm or more, and preferably 5 µm or more. When the average pore diameter of the ceramic substrate falls within this range, the thermal conductivity of the ceramic substrate can be adjusted more stably within the aforementioned range. The average pore diameter is measured, for example, by mercury porosimetry.

[0018] The catalyst layer 2 is typically supported by the ceramic substrate 1. In the illustrated example, the catalyst layer 2 is laminated on the surface of the ceramic substrate 1. The porosity of the catalyst layer 2 is preferably 25% or more, more preferably 30% or more, still more preferably 35% or more, and particularly preferably 40% or more. When the porosity of the catalyst layer is not less than the above lower limit, the gas diffusibility in the catalyst layer can be stably improved. On the other hand, the porosity of the catalyst layer 2 is, for example, 80% or less, preferably 75% or less, more preferably 65% or less, and still more preferably 55% or less. When the porosity of the catalyst layer is not more than the above upper limit, sufficient thermal conductivity of the catalyst layer can be ensured, and the thermal diffusibility of the catalyst layer can be stably improved.

[0019] The thermal conductivity of the catalyst layer 2 is, for example, 0.05 W / m·K or more, and preferably 0.08 W / m·K or more. On the other hand, the thermal conductivity of the catalyst layer 2 is, for example, 200 W / m·K or less. The thermal conductivity of the catalyst layer is measured, for example, by the hot wire method.

[0020] The thickness of the catalyst layer 2 is, for example, 0.01 μm or more, preferably 0.1 μm or more, more preferably 10 μm or more, further preferably more than 20 μm, particularly preferably 21 μm or more, especially preferably 50 μm or more, and most preferably 100 μm or more. On the other hand, the thickness of the catalyst layer 2 is, for example, 550 μm or less, preferably 500 μm or less, more preferably 400 μm or less, further preferably less than 300 μm, and particularly preferably 280 μm or less. When the thickness of the catalyst layer falls within the above range, gas diffusibility in the catalyst layer can be improved more stably.

[0021] The catalyst layer 2 contains the above-described catalyst. The catalyst contains any appropriate metal element as an active component. The catalyst may contain the metal element in a metallic state, may contain a salt of the metal element, or may contain an oxide of the metal element. Preferably, the catalyst contains the metal element in a metallic state.

[0022] Examples of the metal element include alkali metals, alkaline earth metals, and transition metals. Specific examples of the transition metal include Co, Fe, Pt, Ru, Rh, Pd, Ni, Cu, Ag, Au, Ir, Os, Mn, Ta, Mo, Zn, Cr, Re, V, and Zr, preferably Co, Fe, Pt, Ru, Rh, Pd, Ni, Cu, Ag, Au, Ir, Os, Mn, Ta, Mo, Zn, and Cr. Examples of the alkali metal include Li, Na, K, and Rb. Examples of the alkaline earth metal include Ca, Ba, and Sr. These metal elements may be used alone or in combination.

[0023] In addition to the above-described active component, the catalyst may further contain a carrier. The carrier is capable of supporting the active component (typically a transition metal). The carrier is formed of any appropriate inorganic material depending on the application. Examples of the inorganic material include oxides, carbides, nitrides, sulfides, halides, hydrides, hydroxides, and zeolites. The inorganic materials may be used alone or in combination.

[0024] Among such inorganic materials, oxides are preferred. Specific examples of oxides include cerium oxide, silicon oxide, zirconium oxide, yttrium oxide, aluminum oxide, magnesium oxide, titanium oxide, and composite oxides thereof.

[0025] When the catalyst contains an active ingredient and a support, the content ratio of the active ingredient is, for example, 0.01 to 80 parts by mass, preferably 1 to 50 parts by mass, and more preferably 1 to 20 parts by mass, per 100 parts by mass of the support. If the content ratio of the active ingredient is within this range, the activity of the catalyst can be improved more stably.

[0026] In one embodiment, the catalyst layer 2 contains a methanation catalyst. In other words, in one embodiment, the reactor 100 is a methane production reactor. The methanation catalyst can typically promote the methanation reaction shown in formula (I) and / or formula (II) above. The methanation catalyst preferably contains a transition metal, and more preferably contains Ni. The presence of Ni in the methanation catalyst can further promote the methanation reaction described above. The methanation catalyst may also contain cerium oxide as a support. When such an oxide-containing support bears the above-mentioned active component (especially Ni), the activity of the methanation catalyst can be stably improved.

[0027] When the catalyst is a methanation reaction catalyst, in one embodiment, the raw material gas supplied to the gas flow path 15 further contains oxygen. In this case, a combustion reaction shown in the following formula (IX) may proceed in the gas flow path 15. Since this combustion reaction (IX) is an exothermic reaction, the heat of reaction generated can be effectively utilized to continue the methanation reactions of formulas (I) and (II) described above. ２ +2H ２ →2H ２O...(IX) On the other hand, the above combustion reaction (IX) has a faster reaction rate than the above methanation reaction and may proceed preferentially in the upstream portion of the gas flow path in the direction of raw material gas supply. As a result, localized high-temperature areas (hot spots) may be formed in the upstream portion of the gas flow path. If hot spots are formed, a decrease in methane yield and / or deterioration of the methanation reaction catalyst may occur. In contrast, in one embodiment, since the thermal conductivity of the ceramic substrate is within the above range, the reaction heat generated by the combustion reaction (IX) can also be rapidly diffused from the catalyst layer to the ceramic substrate. As a result, even if the raw material gas contains more oxygen, the temperature of the catalyst layer can be appropriately controlled. This makes it possible for the reactor 100 to stably carry out methanation, which continues the methanation reaction with external heating stopped.

[0028] In another embodiment, the catalyst layer 2 contains an FT reaction catalyst. In other words, in another embodiment, the reactor 100 is an FT reactor. The FT reaction catalyst can typically promote at least one of the FT reactions shown in formulas (III) to (VI) above, and the alcohol production reactions shown in formulas (VII) and (VIII) above. The FT reaction catalyst preferably contains a transition metal, and more preferably contains Co and / or Fe. If the FT reaction catalyst contains Co and / or Fe, the above FT reaction can be further promoted. In addition to the transition metal, the FT reaction catalyst may also contain an alkali metal. With such a configuration, the FT reaction catalyst can promote a reverse shift reaction that converts carbon dioxide into carbon monoxide, in addition to the FT reaction. Furthermore, the FT reaction catalyst may contain silicon oxide as a support. If a support containing such an oxide supports the above active component (especially Co), the activity of the FT reaction catalyst can be stably improved.

[0029] The catalyst contained in the catalyst layer 2 has any appropriate shape. The catalyst is typically in the form of particles. Hereinafter, a particulate catalyst may be referred to as catalyst particles. In one embodiment, the catalyst layer 2 contains an aggregate formed by aggregation of a plurality of catalyst particles. Aggregates of a plurality of catalyst particles can form mesopores in the catalyst layer 2. The average secondary particle diameter of the plurality of catalyst particles is, for example, 0.01 µm to 50 µm, and preferably 0.1 µm to 20 µm. The standard deviation of the average secondary particle diameter of the plurality of catalyst particles is, for example, 0.1 µm to 40 µm, and preferably 0.5 µm to 30 µm. Here, the secondary particle diameter means D50 in the volume-based cumulative particle size distribution of a particle group containing the aggregate. When the average secondary particle diameter of the catalyst particles and / or the standard deviation thereof falls within such a range, suitable mesopores can be stably formed in the catalyst layer, and the porosity of the catalyst layer can be adjusted more stably within the above-mentioned range. The secondary particle diameter of the catalyst particles is measured using, for example, a laser diffraction / scattering particle size distribution analyzer.

[0030] The content ratio of the catalyst in the catalyst layer 2 is, for example, 10% by mass to 100% by mass, and preferably 50% by mass to 100% by mass. The catalyst loading in the catalyst layer 2 is, for example, 0.007 mg / mm ２ to 1.869 mg / mm ２ . When the catalyst content ratio and / or the catalyst loading falls within such a range, a desired chemical reaction (for example, methanation reaction, FT reaction) can be stably progressed in the reactor.

[0031] The mass of the catalyst per unit volume of the honeycomb-shaped substrate including the gas flow path 15 is, for example, 30 g / L or more, and preferably 50 g / L or more. On the other hand, the upper limit of the mass of the catalyst per unit volume of the honeycomb-shaped substrate including the gas flow path 15 is typically 1000 g / L or less.

[0032] The catalyst layer 2 may contain additives in addition to the catalyst (e.g., a methanation reaction catalyst, an FT reaction catalyst). Examples of additives include fillers, binders, thermal conductors, and heat transfer materials. The additives can be used alone or in combination. The proportion of additives added is, for example, 0.1 to 90 parts by mass, preferably 0.1 to 50 parts by mass, per 100 parts by mass of catalyst.

[0033] B. Reactor Details Next, the details of a reactor according to one embodiment will be described. As shown in Figures 1 and 2, in one embodiment, the reactor 100 has a flow-through structure.

[0034] B-1. Ceramic Substrate The ceramic substrate 1 is composed of any suitable ceramic material. Examples of ceramic materials include zirconia-based materials, alumina-titanium carbide-based composite materials, Si-SiC-based composite materials, aluminum nitride, aluminum oxide, silicon nitride, silicon carbide, zirconia, cordierite, and mullite. These ceramic materials can be used individually or in combination. Among these ceramic materials, cordierite and Si-SiC-based composite materials are preferred.

[0035] In one embodiment, the ceramic substrate 1 is composed of a Si-SiC composite material. In other words, the ceramic substrate 1 contains Si and SiC. When the ceramic substrate contains Si and SiC, the thermal conductivity of the ceramic substrate can be stably adjusted to the above-mentioned range.

[0036] Si-SiC composite materials may be porous or dense. Porous Si-SiC composite materials are described in detail, for example, in Japanese Patent Publication No. 2002-201082. Dense Si-SiC composite materials are described in detail, for example, in Japanese Patent Publication No. 11-035376. The entire descriptions of these publications are incorporated herein by reference. Among Si-SiC composite materials, dense materials are preferred.

[0037] Such a ceramic substrate 1 has a shape capable of supporting the catalyst layer 2. Preferably, the ceramic substrate 1 has any suitable configuration that defines the gas flow path 15. Examples of the shape of the ceramic substrate 1 include a cylindrical shape and a honeycomb shape. In one embodiment, the reactor 100 comprises a honeycomb substrate 1a and a catalyst layer 2. The honeycomb substrate 1a has partition walls 13 that define a plurality of cells 14. At least some of the plurality of cells 14 include a gas flow path 15. In the illustrated example, all of the plurality of cells 14 include a gas flow path 15. The catalyst layer 2 is provided inside the cells 14. If the reactor has such a configuration, when the raw material gas is supplied to the gas flow path, the raw material gas and the catalyst in the catalyst layer (e.g., a methanation reaction catalyst, an FT reaction catalyst) can be efficiently brought into contact. Therefore, the above-mentioned chemical reactions (e.g., methanation reaction, FT reaction) can proceed smoothly, and the reaction yield (e.g., the yield of hydrocarbons such as methane) can be further improved.

[0038] The honeycomb-shaped substrate 1a has any suitable shape (overall shape). Examples of shapes for the honeycomb-shaped substrate 1a include a cylindrical shape with a circular base, an elliptical prism shape with an elliptical base, a prismatic prism shape with a polygonal base, and a columnar shape with an irregular base. In one embodiment, the honeycomb-shaped substrate 1a has a cylindrical shape. The outer diameter and length of the honeycomb-shaped substrate 1a are appropriately set according to the purpose.

[0039] In the illustrated example, the honeycomb-shaped substrate 1a comprises an outer wall 16 and a partition wall 13 located inside the outer wall 16. The outer wall 16 and the partition wall 13 may be formed integrally or as separate components. In the illustrated example, the outer wall 16 and the partition wall 13 are formed integrally. Note that the honeycomb-shaped substrate 1a does not necessarily have an outer wall 16. In this case, the honeycomb-shaped substrate 1a is composed of partition walls 13.

[0040] The outer wall 16 has a cylindrical shape. The thickness of the outer wall 16 is set arbitrarily and appropriately. The thickness of the outer wall 16 is, for example, 1 mm to 10 mm, or for example, 2 mm to 8 mm.

[0041] As described above, the partition wall 13 defines a plurality of cells 14. The cells 14 extend in the longitudinal direction (axial direction) of the honeycomb substrate 1a from the first end face E1 (inlet end face) to the second end face E2 (outlet end face) of the honeycomb substrate 1a (see Figure 2). The cells 14 have any suitable shape in the cross section in a direction perpendicular to the longitudinal direction of the honeycomb substrate 1a. Examples of cell cross-sectional shapes include triangles, quadrilaterals, pentagons, polygons with hexagons or more, circles, and ellipses. The cross-sectional shapes and sizes of the cells may all be the same, or at least some may differ. Among such cell cross-sectional shapes, quadrilaterals are preferred, and squares or rectangles are more preferred.

[0042] The cell density in the honeycomb substrate 1a is, for example, 40 cpsi or more, preferably 50 cpsi or more, more preferably 100 cpsi or more, and even more preferably 200 cpsi or more. On the other hand, the cell density in the honeycomb substrate 1a is, for example, 1000 cpsi or less, preferably 900 cpsi or less. When the cell density is within this range, the raw material gas can be efficiently brought into contact with the catalyst layer. In this specification, "cell density of the honeycomb substrate" means the cell density of the cross-section in the longitudinal direction (direction in which the cells extend) of the honeycomb substrate, and "cpsi" means 6.4516 cm² of the said cross-section. ２ This refers to the number of cells per square inch.

[0043] In the illustrated example, the partition wall 13 has a first partition wall 13a and a second partition wall 13b that are perpendicular to each other, and the first partition wall 13a and the second partition wall 13b define a plurality of cells 14. The cross-sectional shape of the cells 14 is rectangular, except for the parts where the first partition wall 13a and the second partition wall 13b are in contact with the outer wall 16. Note that the configuration of the partition wall is not limited to the partition wall 13 described above. The partition wall may have a first partition wall extending in the radial direction and a second partition wall extending in the circumferential direction, and these may define a plurality of cells.

[0044] The thickness of the partition wall 13 can be set arbitrarily and appropriately. Typically, the thickness of the partition wall 13 is thinner than the thickness of the outer wall 16. The thickness of the partition wall 13 is, for example, 0.0508 mm or more, preferably 0.0635 mm or more, more preferably 0.1016 mm or more, even more preferably 0.2032 mm or more, particularly preferably exceeding 0.2540 mm, and especially preferably 0.2541 mm or more. On the other hand, the thickness of the partition wall 13 is, for example, 1.52 mm or less, preferably 1.27 mm or less, more preferably 1.00 mm or less, even more preferably 0.65 mm or less, particularly preferably 0.55 mm or less, and especially preferably 0.400 mm or less. If the thickness of the partition wall is within this range, the mechanical strength of the honeycomb substrate can be made sufficient, and the cell density can be adjusted to the above range. The thickness of the partition wall is measured, for example, by cross-sectional observation using an SEM (scanning electron microscope).

[0045] The partition wall 13 may or may not have pores. The range of porosity in the partition wall 13 is, for example, the same as the range of porosity of the ceramic substrate 1 described above. The range of average pore diameter in the partition wall 13 is, for example, the same as the range of average pore diameter of the ceramic substrate 1 described above. The range of thermal conductivity of the partition wall 13 is, for example, the same as the range of thermal conductivity of the ceramic substrate 1 described above.

[0046] The bulk density of the partition wall 13 can be appropriately set depending on the purpose. For example, the bulk density of the partition wall 13 is 1.0 g / cm³. ３ ~3.0 g / cm ３ Preferably 2.0 g / cm³ ３ ~3.0 g / cm ３ The bulk density is measured, for example, by the Archimedes method.

[0047] B-2. In the illustrated example of the catalyst layer, the catalyst layer 2 described above is provided on the surface of the partition wall 13. When the catalyst layer is formed on the surface of the partition wall, the reaction heat of the chemical reaction (e.g., FT reaction, methanation reaction and / or combustion reaction) can be smoothly transferred from the catalyst layer to the partition wall. Therefore, stable heat uniformity in the gas flow path can be achieved. In the reactor 100, the gas flow path 15 is formed in the portion of the cross-section of the cell 14 where the catalyst layer 2 is not formed (typically the central part). The catalyst layer 2 may be formed on the entire inner surface of the partition wall 13 (i.e., surrounding the gas flow path 15) as shown in the illustrated example, or it may be formed on a part of the surface of the partition wall. When the catalyst layer 2 is formed on the entire inner surface of the partition wall 13, the reaction yield (e.g., the yield of hydrocarbons such as methane) can be improved more stably.

[0048] The gas flow path 15 is a space formed inside the cell 14 and extends from the first end face E1 (inlet end face) to the second end face E2 (outlet end face), similar to the cell 14 (see Figure 2). The cross-sectional shape of the gas flow path 15 can be the same as that of the cell 14 described above, preferably a quadrilateral, and more preferably a square or rectangle. The cross-sectional shape and size of the gas flow path 15 may all be the same, or at least some parts may differ.

[0049] C. Method for Manufacturing a Reactor Next, a method for manufacturing a reactor 100 according to one embodiment will be described. In one embodiment, the method for manufacturing a reactor 100 includes a step of preparing a slurry for forming a catalyst layer 2 (slurry preparation step) and a step of applying the slurry to a ceramic substrate 1 to form a catalyst layer 2 (catalyst layer formation step).

[0050] C-1. Slurry Preparation Process In the slurry preparation process, first, the catalyst described above (e.g., methanation reaction catalyst, FT reaction catalyst) is prepared. The catalyst (e.g., methanation reaction catalyst, FT reaction catalyst) is typically pulverized into particulate matter by any suitable means. This yields particulate catalyst (catalyst particles), and the average secondary particle diameter and / or standard deviation of the catalyst particles are adjusted to the range described above. Examples of catalyst pulverization methods include pot mills, jet mills, hammer mills, and roll crushers, with pot mills being preferred.

[0051] Next, the catalyst (preferably catalyst particles) is added to the solvent and stirred by any suitable method. Examples of solvents include water and organic solvents, with organic solvents being preferred. This prepares a slurry in which the catalyst is dispersed in the solvent. The content of the catalyst in the slurry is, for example, 1% to 50% by mass, and preferably 5% to 15% by mass.

[0052] In one embodiment, a pore-forming agent is further added to the slurry. When a pore-forming agent is added to the slurry, the porosity of the catalyst layer formed can be further stabilized and adjusted to the above-mentioned range. Examples of pore-forming agents include particulate polymers and chain polymers. The pore-forming agents can be used alone or in combination. Among the pore-forming agents, particulate polymers are preferred. The addition ratio of the pore-forming agent is, for example, 0.1 to 80 parts by mass, preferably 15 to 75 parts by mass, per 100 parts by mass of catalyst.

[0053] C-2. Catalyst layer formation process In the catalyst layer formation process, the ceramic substrate 1 described above is prepared in advance, and the slurry described above is applied to any appropriate position on the ceramic substrate 1. The method of applying the slurry is arbitrarily and appropriately selected according to the shape of the ceramic substrate 1. Examples of slurry application methods include the wash coat method, spray coat method, roller coat method, and spin coat method.

[0054] As shown in Figures 1 and 2, when the ceramic substrate 1 is a honeycomb substrate 1a, the slurry is applied to the surface of the partition wall 13 by a wash-coat method. More specifically, the slurry is poured into the cells 14 of the honeycomb substrate 1a. This allows the slurry to be smoothly applied to the surface of the partition wall 13, forming a slurry coating. After that, the slurry coating is dried as needed. The application and drying of the slurry may be repeated until the catalyst layer 2 reaches the desired thickness. Furthermore, the slurry coating may be fired, typically in an atmospheric environment (degreasing step). This removes organic components (typically pore-forming materials) contained in the slurry coating. In the degreasing step, the firing temperature is, for example, 150°C to 450°C, and the firing time is, for example, 0.5 hours to 5 hours. Through the above steps, the catalyst layer 2 is formed from the slurry, and a reactor 100 comprising the ceramic substrate 1 (honeycomb substrate 1a) and the catalyst layer 2 is manufactured.

[0055] D. Methanation Reaction (Method for Producing Methane) Next, with reference to Figure 2, a methanation reaction (method for producing methane) in a reactor according to one embodiment will be described. In a methanation reaction (method for producing methane) in a reactor, typically the reactor is heated to the reaction start temperature before supplying the raw material gas. The reaction start temperature is, for example, 100°C or higher, preferably 150°C or higher. On the other hand, the upper limit of the reaction start temperature is typically 600°C.

[0056] Next, the raw material gas is supplied to the gas channel of the reactor, which has been heated to the reaction start temperature, at an appropriate space velocity (SV). This causes the raw material gas to flow into the gas channel and come into contact with the methane reaction catalyst, which has also been heated to the reaction start temperature.

[0057] The carbon dioxide content in the raw material gas is, for example, 0.1 mol% to 20 mol%, preferably 1.0 mol% to 15 mol%. The hydrogen content in the raw material gas is, for example, 0.4 mol% to 80 mol%, preferably 4.0 mol% to 80 mol%. In one embodiment, the raw material gas contains oxygen in addition to carbon dioxide and hydrogen. The oxygen content in the raw material gas is, for example, 0.5 mol% to 10 mol%, preferably 1.0 mol% to 5.0 mol%. Furthermore, the raw material gas may contain nitrogen as the remainder.

[0058] The space velocity (SV) of the source gas is, for example, 2500 h. －１ The above, preferably 3000h －１ That's all. On the other hand, the space velocity (SV) of the raw material gas is, for example, 100,000 h. －１ The following applies:

[0059] When the raw material gas contains oxygen in addition to carbon dioxide and hydrogen, typically the hydrogen combustion reaction shown in equation (IX) above proceeds preferentially over the methane reactions shown in equations (I) and (II) above. In this case, the heat of reaction generated by the hydrogen combustion reaction is used to continue the hydrogen combustion reaction and to initiate the methane reaction. Once the methane reaction starts, heat of reaction is also generated by the methane reaction. This heat of reaction is uniformly diffused by the ceramic substrate, and the temperature is suitably controlled throughout the reactor. As a result, the combustion reaction and the methane reaction continue stably, and the methane reaction continues stably even after the combustion reaction is completed. Therefore, in one embodiment, external heating of the reactor is stopped.

[0060] With external heating of the reactor stopped, the temperature in the gas flow path of the reactor (reaction temperature) is maintained throughout, for example, between 100°C and 600°C, preferably between 250°C and 450°C. Maintaining a reaction temperature within this range allows the methanation reaction described above to continue more stably.

[0061] As a result, carbon oxide and hydrogen react in the reactor's gas flow path to produce methane gas. Subsequently, the methane-containing gas is continuously discharged from the reactor's gas flow path. The methane-containing gas contains methane gas and water vapor. In addition to methane gas and water vapor, the methane-containing gas may also contain unreacted raw material gases (oxygen, hydrogen, and / or carbon oxide).

[0062] The methane yield is the percentage of methane relative to the total amount of methane and unreacted carbon oxide in the methane-containing gas, and is, for example, 65% or more, preferably 70% or more, more preferably 75% or more, and even more preferably 80% or more. On the other hand, the methane yield is, for example, 100% or less, or for example, 95% or less. When the methane yield is within this range, the energy and / or cost required to separate methane from the methane-containing gas can be reduced.

[0063] E. FT Synthesis Reaction Next, with reference to Figure 2, an FT synthesis reaction in a reactor according to another embodiment will be described. In an FT synthesis reaction, typically the reactor is heated to the reaction start temperature before the supply of the raw material gas. The reaction start temperature is, for example, 100°C or higher, preferably 150°C or higher. On the other hand, the upper limit of the reaction start temperature is typically 450°C.

[0064] Next, the raw material gas is supplied to the gas channel of the reactor, which has been heated to the reaction start temperature, at an appropriate space velocity (SV). This causes the raw material gas to flow into the gas channel and come into contact with the FT reaction catalyst, which has been heated to the reaction start temperature.

[0065] The carbon oxide content in the raw material gas is, for example, 0.1 mol% to 50 mol%, preferably 10 mol% to 50 mol%. The hydrogen content in the raw material gas is, for example, 0.1 mol% to 80 mol%, preferably 10 mol% to 80 mol%. Furthermore, the raw material gas may contain nitrogen as the remainder.

[0066] The space velocity (SV) of the source gas is, for example, 100 h. －１ The above, preferably 500h －１That's all. On the other hand, the space velocity (SV) of the raw material gas is, for example, 15,000 h. －１ The following applies:

[0067] Once the FT reaction begins, it generates reaction heat. This reaction heat is uniformly diffused by the ceramic substrate, and the temperature is suitably controlled throughout the reactor. The temperature in the gas flow path (reaction temperature) is maintained throughout the reactor, for example, between 100 and 600°C, preferably between 200 and 400°C. When the reaction temperature is within this range, the FT reaction described above can stably maintain the production of hydrocarbons with the desired number of carbon atoms.

[0068] As a result, carbon oxide and hydrogen react in the reactor's gas channel to produce hydrocarbon gas. Subsequently, the hydrocarbon-containing gas is continuously discharged from the reactor's gas channel. The hydrocarbon-containing gas contains hydrocarbons (referring to olefins, paraffins, naphthenes, aromas, and alcohols) and water vapor. In addition to the hydrocarbon gas and water vapor, the hydrocarbon-containing gas may also contain unreacted raw material gases (hydrogen and / or carbon oxide).

[0069] The hydrocarbon yield for a desired number of carbon atoms is the percentage of hydrocarbons for that number of carbon atoms relative to the total amount of hydrocarbons and unreacted carbon oxides in the hydrocarbon-containing gas, for example, 25% or more, preferably 50% or more, more preferably 75% or more, and even more preferably 80% or more. On the other hand, the hydrocarbon yield for a desired number of carbon atoms may be, for example, 100% or less, or for example, 95% or less. When the hydrocarbon yield for a desired number of carbon atoms is within such a range, the energy and / or cost required to separate hydrocarbons from the hydrocarbon-containing gas can be reduced.

[0070] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. The measurement methods for each characteristic are as follows.

[0071] (1) Measurement of Thermal Conductivity of Honeycomb Substrates The honeycomb substrates prepared in the examples and comparative examples were processed to a predetermined size, and the thermal diffusivity was measured by Laser-PIT (optical alternating current method). The specific heat of the honeycomb substrate was measured by differential scanning calorimetry (DSC). Furthermore, the bulk density of the honeycomb substrate was measured by Archimedes density spectroscopy. From the obtained thermal diffusivity, specific heat, and bulk density, the thermal conductivity of the honeycomb substrate was calculated based on the above formula (1). In cases where a catalyst layer was supported on the honeycomb substrate, the thermal conductivity was measured after preparing a sample for measurement in which the catalyst layer had been removed by a solvent or the like.

[0072] (2) Measurement of the Thickness of the Catalyst Layer The reactors manufactured in the examples and comparative examples were embedded in resin, and the cross-section of the reactor, cut perpendicular to the axial direction of the honeycomb substrate, was imaged using a digital microscope (Keyence Corporation, product name "VHX-7100", magnification 100x). Using the analysis software attached to the device, the straight-line distance from the flat interface between the honeycomb substrate and the catalyst layer to the flat interface between the catalyst layer and the resin was measured at 10 or more locations, and the average of these straight-line distances was calculated as the thickness of the catalyst layer. The automatic edge detection function of the analysis software was used as the discrimination method.

[0073] (3) Measurement of Porosity of Catalyst Layer The reactors manufactured in the examples and comparative examples were embedded in resin, and the cross-section of the reactor, cut perpendicular to the axial direction of the honeycomb substrate, was imaged using a scanning electron microscope (Hitachi High-Technologies Corporation, product name "S-3400N", magnification: 1000x). The porosity of the catalyst layer was calculated from the obtained scanning electron microscope images using image analysis software (ImageJ). Only the catalyst layer was extracted as the target of analysis, and binarization analysis was performed using brightness as the threshold to obtain a binarized image. The threshold for binarization was set using Otsu's binarization method as the discriminant analysis method. From the obtained binarized image, the regions showing the catalyst and the regions showing the resin (the parts that were originally pores) were distinguished, and the porosity of the catalyst layer was calculated as the percentage of the area of ​​the resin region to the total area of ​​the regions showing the catalyst and the resin region.

[0074] Examples of the methanation reaction are shown below. <Example 1> <<Preparation of honeycomb substrate>> 80 parts by mass of SiC raw material powder and 20 parts by mass of metallic Si powder were extruded into a clay mold, dried, calcined at 550°C for 3 hours in an oxidizing atmosphere, and then fired at 1450°C for 2 hours in a non-oxidizing atmosphere. This prepared the honeycomb substrate shown in Figure 1. The honeycomb substrate had a cylindrical shape with a diameter of 20 mm and a length of 50 mm. The honeycomb substrate was composed of a Si-SiC composite material. The honeycomb substrate had partitions defining multiple cells and an outer wall surrounding the partitions. The cross-sectional shape of the cells was square. The cell density in the honeycomb substrate was 300 cpsi, and the thickness of the partitions was 0.254 mm. Table 1 shows the thermal conductivity, porosity, and average pore diameter of the honeycomb substrate (partitions).

[0075] <<Preparation of Methanation Reaction Catalyst>> Cerium(IV) oxide particles (manufactured by Daiichi Kigenso Kagaku Kogyo Co., Ltd.) were introduced into distilled water and stirred under reduced pressure at room temperature (23°C) for 12 hours. This obtained a dispersion of metal oxide particles. Nickel(II) nitrate hexahydrate was dissolved in distilled water to obtain an aqueous nickel nitrate solution. Next, the aqueous nickel nitrate solution was added to the dispersion of metal oxide particles and stirred at room temperature (23°C) for 2 hours. After that, the mixture of the dispersion and the aqueous solution was heated to 80°C while stirring to evaporate the water. Next, the remaining solid was heated at 500°C for 3 hours. This obtained methanation reaction catalyst particles (hereinafter referred to as catalyst particles). After that, the catalyst particles were crushed in a pot mill to adjust the particle size. The average secondary particle diameter of the catalyst particles was 1.437 μm, and the standard deviation of the secondary particle diameter of the catalyst particles was 1.028 μm. The catalyst particles contained nickel oxide (NiO) and cerium oxide (IV) supporting the nickel oxide (NiO). In the catalyst particles, the Ni content was 10 parts by mass per 100 parts by mass of cerium oxide.

[0076] <<Preparation of the Catalyst Layer>> The obtained catalyst particles were dispersed in ethanol to prepare a catalyst slurry. The content of catalyst particles in the catalyst slurry was 10% by mass. Next, polymethyl methacrylate (manufactured by Sekisui Chemical Co., Ltd.) was added to the catalyst slurry as a pore-forming agent. The addition ratio of the pore-forming agent was 18 parts by mass per 100 parts by mass of catalyst particles. Next, at room temperature and pressure (23°C, 0.1 MPa), the catalyst slurry was poured into the cells of the honeycomb substrate prepared above. This coated the surface of the partition wall with the catalyst slurry. After that, the catalyst slurry coated on the surface of the partition wall was left to dry in a blown air environment at 25°C for 20 minutes. After repeating the above coating and drying process, it was fired at 300°C for 2 hours in an air atmosphere to form a catalyst layer on the surface of the partition wall. The catalyst layer contained aggregates of catalyst particles. The amount of catalyst particles supported per unit volume of the honeycomb substrate, including the flow channels, was 254 g / L. The porosity and thickness of the catalyst layer are shown in Table 1. Based on the above, a reactor comprising the honeycomb substrate and the catalyst layer was manufactured.

[0077] <Example 2> A reactor was manufactured in the same manner as in Example 1, except that the amount of polymethyl methacrylate added was changed to alter the porosity and thickness of the catalyst layer as shown in Table 1.

[0078] <Example 3> A reactor was manufactured in the same manner as in Example 1, except that the amount of polymethyl methacrylate added was changed to alter the porosity and thickness of the catalyst layer as shown in Table 1.

[0079] <Example 4> A reactor was manufactured in the same manner as in Example 1, except that the mixing ratio of SiC raw material powder and metallic Si powder was changed to 84 parts by mass:16 parts by mass, and the amount of polymethyl methacrylate added was changed to alter the porosity and thickness of the catalyst layer as shown in Table 1.

[0080] <Example 5> A reactor was manufactured in the same manner as in Example 4, except that the amount of polymethyl methacrylate added was changed to alter the porosity and thickness of the catalyst layer as shown in Table 1.

[0081] <Example 6> A reactor was manufactured in the same manner as in Example 4, except that the amount of polymethyl methacrylate added was changed to alter the porosity and thickness of the catalyst layer as shown in Table 1.

[0082] <Example 7> A reactor was manufactured in the same manner as in Example 1, except that the honeycomb substrate made of Si-SiC composite material was changed to a honeycomb substrate prepared as described below, and the amount of polymethyl methacrylate added was changed to change the porosity and thickness of the catalyst layer as shown in Table 1. A clay containing SiC powder was extruded and then dried to prepare a honeycomb dry body. The honeycomb dry body had the same size and structure as the honeycomb substrate in Example 1. In addition, a material powder containing Si powder was press-molded and then dried to obtain a Si feed body. Next, with the Si feed body in contact with the honeycomb dry body, it was heated at 1500°C for 4 hours under reduced pressure conditions (200 Pa) to impregnate the honeycomb dry body with molten metal containing Si. The amount of molten Si metal was 17 parts by mass per 100 parts by mass of the honeycomb dry body. In this way, a honeycomb substrate made of Si-SiC composite material was prepared.

[0083] <Example 8> A reactor was manufactured in the same manner as in Example 7, except that the amount of polymethyl methacrylate added was changed to alter the porosity and thickness of the catalyst layer as shown in Table 1.

[0084] <Example 9> A reactor was manufactured in the same manner as in Example 7, except that the amount of polymethyl methacrylate added was changed to alter the porosity and thickness of the catalyst layer as shown in Table 1.

[0085] <Example 10> A reactor was manufactured in the same manner as in Example 7, except that the amount of molten Si metal was changed to 25 parts by mass per 100 parts by mass of honeycomb dry body, and the amount of polymethyl methacrylate added was changed to alter the porosity and thickness of the catalyst layer as shown in Table 1. The honeycomb substrate partitions in the reactor of Example 10 did not have pores.

[0086] <Examples 11 and 13> Reactors were manufactured in the same manner as in Example 10, except that the amount of polymethyl methacrylate added was changed to alter the porosity and thickness of the catalyst layer as shown in Table 1.

[0087] <Example 12> A reactor was manufactured in the same manner as in Example 10, except that the amount of polymethyl methacrylate added was changed to alter the porosity and thickness of the catalyst layer as shown in Table 1.

[0088] <Comparative Example 1> A reactor was manufactured in the same manner as in Example 1, except that the clay containing SiC raw material powder and metallic Si powder was changed to clay containing cordierite raw material, and the amount of polymethyl methacrylate added was changed to alter the porosity and thickness of the catalyst layer as shown in Table 1.

[0089] <Comparative Example 2> The reactor was manufactured in the same manner as in Comparative Example 1, except that the amount of polymethyl methacrylate added was changed to alter the porosity and thickness of the catalyst layer as shown in Table 1.

[0090] <Comparative Example 3> The reactor was manufactured in the same manner as in Comparative Example 1, except that the amount of polymethyl methacrylate added was changed to alter the porosity and thickness of the catalyst layer as shown in Table 1.

[0091] <Comparative Example 4> The reactor was manufactured in the same manner as in Comparative Example 1, except that the blending ratio of cordierite raw materials and the amount of polymethyl methacrylate added were changed to alter the porosity and thickness of the catalyst layer as shown in Table 1.

[0092] <Comparative Example 5> The reactor was manufactured in the same manner as in Comparative Example 4, except that the amount of polymethyl methacrylate added was changed to alter the porosity and thickness of the catalyst layer as shown in Table 1.

[0093] <Comparative Example 6> The reactor was manufactured in the same manner as in Comparative Example 4, except that the amount of polymethyl methacrylate added was changed to alter the porosity and thickness of the catalyst layer as shown in Table 1.

[0094] <Comparative Example 7> A reactor was manufactured in the same manner as in Example 10, except that the amount of polymethyl methacrylate added was changed to alter the porosity and thickness of the catalyst layer as shown in Table 1.

[0095] <Methanation Test> The reactors obtained in the examples and comparative examples were inserted into a reaction tube with an inner diameter of 21 mm. As a catalyst pretreatment, hydrogen gas was introduced into the reaction tube, and the reactor was heated at 500°C for 1 hour in an electric furnace installed on the outer circumference of the reaction tube to reduce the methanation reaction catalyst. Next, nitrogen gas was flowed into the reaction tube to lower the temperature of the electric furnace to 300°C, and then the raw material gas under test condition A or B was introduced into the reaction tube. The raw material gas under test condition A contained 10 mol% carbon dioxide, 3 mol% oxygen, 46 mol% hydrogen, and the remainder nitrogen (CO ２ / H ２ / N ２ / O ２ = 10 / 46 / 41 / 3 [mol ratio]). The raw material gas under test condition B contained 20 mol% carbon dioxide and 80 mol% hydrogen (CO ２ / H ２ = 20 / 80 [mol ratio]). In other words, the raw material gas under test condition A contains oxygen, and the raw material gas under test condition B does not contain oxygen. Note that in Examples 1 to 12 and Comparative Examples 1 to 7, the space velocity SV of the raw material gas was set to 10,000 h －１ The gas flow rate of the raw material gas was set to 2.5 L / min. In addition, in Example 13, the space velocity SV of the raw material gas was set to 3000 h －１ The settings were adjusted, and the gas flow rate of the raw material gas was set to 0.8 L / min. As a result, the raw material gas was supplied to the gas flow path of the reactor, and methane-containing gas flowed out of the reaction tube. The methane-containing gas flowing out of the reaction tube was passed through a cooling trap to produce H ２O was removed. Subsequently, the gas composition of the methane-containing gas was analyzed using a gas chromatograph-thermal conductivity detector (GC-TCD). Based on the measurement results, the yield (%) from carbon oxide to methane was calculated using the following formula (A): Methane yield (%) = (Amount of methane contained in the methane-containing gas (volume %) / Sum of methane and carbon oxide contained in the methane-containing gas (volume %)) × 100 ... (A) In the case of test condition A, the methane yield in Comparative Example 1 was set to 1, and in the case of test condition B, the methane yield in Comparative Example 3 was set to 1, and the methane yields of the other examples and comparative examples were normalized to obtain the methane yield. The results are shown in Table 1.

[0096]

[0097] <Evaluation> As shown in Table 1, if the thermal conductivity of the ceramic substrate is 8 W / m·K or higher, and the porosity of the catalyst layer is 20% or higher, the space velocity SV is 10,000 h －１ Even so, it is clear that the methane yield (amount) can be significantly improved.

[0098] Examples of the FT reaction are shown below. <Example 14> <<Preparation of honeycomb substrate>> A honeycomb substrate was prepared in the same manner as in Example 1. The cell density of the honeycomb substrate was 300 cpsi, and the thickness of the partitions was 0.3048 mm. The thermal conductivity, porosity, and average pore diameter of the honeycomb substrate (partitions) are shown in Table 2.

[0099] <<Preparation of FT reaction catalyst>> Silicon oxide particles (manufactured by Fuji Silysia Chemical Co., Ltd.) were introduced into distilled water and stirred under reduced pressure at room temperature (23°C) for 12 hours. This obtained a dispersion of metal oxide particles. In addition, cobalt(II) nitrate hexahydrate was dissolved in distilled water to obtain an aqueous cobalt nitrate solution. Next, the aqueous cobalt nitrate solution was added to the dispersion of metal oxide particles and stirred at room temperature (23°C) for 2 hours. After that, the mixture of the dispersion and the aqueous solution was heated to 80°C while stirring to evaporate the water. Next, the remaining solid was heated at 500°C for 3 hours. This obtained FT reaction catalyst particles (hereinafter referred to as catalyst particles). After that, the catalyst particles were crushed in a pot mill to adjust the particle size. The average secondary particle diameter of the catalyst particles was 1.735 μm, and the standard deviation of the secondary particle diameter of the catalyst particles was 1.120 μm. The catalyst particles are tricobalt tetroxide (Co ３ O ４ ) and cobalt tetroxide (Co ３ O ４ The catalyst particles contained silicon(IV) dioxide supporting ) and . In the catalyst particles, the Co content was 20 parts by mass per 100 parts by mass of silicon dioxide.

[0100] <<Preparation of the Catalyst Layer>> The catalyst layer was prepared in the same manner as in Example 1, except that an FT reaction catalyst was used. The porosity and thickness of the catalyst layer are shown in Table 2. A reactor comprising a honeycomb substrate and a catalyst layer was thus manufactured.

[0101] <Example 15> A reactor was manufactured in the same manner as in Example 14, except that the amount of polymethyl methacrylate added was changed to alter the porosity and thickness of the catalyst layer as shown in Table 2.

[0102] <Example 16> A reactor was manufactured in the same manner as in Example 14, except that the amount of polymethyl methacrylate added was changed to alter the porosity and thickness of the catalyst layer as shown in Table 2.

[0103] <Example 17> A reactor was manufactured in the same manner as in Example 14, except that the mixing ratio of SiC raw material powder and metallic Si powder was changed to 84 parts by mass:16 parts by mass, and the amount of polymethyl methacrylate added was changed to alter the porosity and thickness of the catalyst layer as shown in Table 2.

[0104] <Example 18> A reactor was manufactured in the same manner as in Example 17, except that the amount of polymethyl methacrylate added was changed to alter the porosity and thickness of the catalyst layer as shown in Table 2.

[0105] <Example 19> A reactor was manufactured in the same manner as in Example 17, except that the amount of polymethyl methacrylate added was changed to alter the porosity and thickness of the catalyst layer as shown in Table 2.

[0106] <Example 20> A reactor was manufactured in the same manner as in Example 14, except that the honeycomb substrate made of Si-SiC composite material was changed to a honeycomb substrate prepared as described below, and the amount of polymethyl methacrylate added was changed to change the porosity and thickness of the catalyst layer as shown in Table 2. A clay containing SiC powder was extruded and then dried to prepare a honeycomb dry body. The honeycomb dry body had the same size and structure as the honeycomb substrate in Example 14. In addition, a material powder containing Si powder was press-molded and then dried to obtain a Si feed body. Next, with the Si feed body in contact with the honeycomb dry body, it was heated at 1500°C for 4 hours under reduced pressure conditions (200 Pa) to impregnate the honeycomb dry body with molten metal containing Si. The amount of molten Si metal was 17 parts by mass per 100 parts by mass of the honeycomb dry body. In this way, a honeycomb substrate made of Si-SiC composite material was prepared.

[0107] <Example 21> A reactor was manufactured in the same manner as in Example 20, except that the amount of polymethyl methacrylate added was changed to alter the porosity and thickness of the catalyst layer as shown in Table 2.

[0108] <Example 22> A reactor was manufactured in the same manner as in Example 20, except that the amount of polymethyl methacrylate added was changed to alter the porosity and thickness of the catalyst layer as shown in Table 2.

[0109] <Example 23> A reactor was manufactured in the same manner as in Example 14, except that the amount of molten Si metal was changed to 25 parts by mass per 100 parts by mass of honeycomb dry body, and the amount of polymethyl methacrylate added was changed to alter the porosity and thickness of the catalyst layer as shown in Table 2.

[0110] <Examples 24 and 26> Reactors were manufactured in the same manner as in Example 23, except that the amount of polymethyl methacrylate added was changed to alter the porosity and thickness of the catalyst layer as shown in Table 2.

[0111] <Example 25> A reactor was manufactured in the same manner as in Example 23, except that the amount of polymethyl methacrylate added was changed to alter the porosity and thickness of the catalyst layer as shown in Table 2.

[0112] <Comparative Example 8> A reactor was manufactured in the same manner as in Example 14, except that the clay containing SiC raw material powder and metallic Si powder was changed to clay containing cordierite raw material, and the amount of polymethyl methacrylate added was changed to alter the porosity and thickness of the catalyst layer as shown in Table 2.

[0113] <Comparative Example 9> The reactor was manufactured in the same manner as in Comparative Example 8, except that the amount of polymethyl methacrylate added was changed to alter the porosity and thickness of the catalyst layer as shown in Table 2.

[0114] <Comparative Example 10> The reactor was manufactured in the same manner as in Comparative Example 8, except that the amount of polymethyl methacrylate added was changed to alter the porosity and thickness of the catalyst layer as shown in Table 1.

[0115] <Comparative Example 11> The reactor was manufactured in the same manner as in Comparative Example 8, except that the blending ratio of cordierite raw materials and the amount of polymethyl methacrylate added were changed to alter the porosity and thickness of the catalyst layer as shown in Table 2.

[0116] <Comparative Example 12> The reactor was manufactured in the same manner as in Comparative Example 11, except that the amount of polymethyl methacrylate added was changed to alter the porosity and thickness of the catalyst layer as shown in Table 2.

[0117] <Comparative Example 13> The reactor was manufactured in the same manner as in Comparative Example 11, except that the amount of polymethyl methacrylate added was changed to alter the porosity and thickness of the catalyst layer as shown in Table 2.

[0118] <Comparative Example 14> A reactor was manufactured in the same manner as in Example 23, except that the amount of polymethyl methacrylate added was changed to alter the porosity and thickness of the catalyst layer as shown in Table 2.

[0119] <FT Reaction Test> The reactors obtained in the examples and comparative examples were inserted into a reaction tube with an inner diameter of 21 mm. As a catalyst pretreatment, hydrogen gas was introduced into the reaction tube, and a heat transfer medium was circulated around the outer circumference of the reaction tube. The reactor was heated at 350°C for 10 hours to reduce the FT reaction catalyst. Next, nitrogen gas was flowed into the reaction tube to lower the internal temperature of the reaction tube to 250°C using the heat transfer medium, and then the raw material gas under test condition C was introduced into the reaction tube. The raw material gas under test condition C contained 32 mol% carbon monoxide, 64 mol% hydrogen, and the remainder nitrogen (CO / H ２ / N ２ = 32 / 64 / 4 [mol ratio]). Note that in Examples 14-25 and Comparative Examples 8-14, the space velocity SV of the raw material gas was set to 1500 h －１ The settings were adjusted, and the gas flow rate of the raw material gas was set to 0.40 L / min. In Example 26, the space velocity SV of the raw material gas was set to 1000 h －１ The settings were adjusted, and the gas flow rate of the raw material gas was set to 0.26 L / min. As a result, the raw material gas was supplied to the gas flow path of the reactor, and hydrocarbon-containing gas flowed out of the reaction tube. The hydrocarbon-containing gas flowing out of the reaction tube was passed through a cooling trap to remove higher hydrocarbons and the generated H ２ O was recovered. Subsequently, the gas composition of the gas containing light hydrocarbons was analyzed using a gas chromatograph-thermal conductivity detector (GC-TCD). The recovered higher hydrocarbons were analyzed using a gas chromatograph-flame ionization detector (GC-FID). Based on the measurement results, carbon atoms with 5 or more carbon atoms (C5＋ The hydrocarbon yield (%) of ) was calculated using the following formula (B). C5 ＋ Yield (%) = (C5 ＋ (Amount of carbon oxide used in hydrocarbon production (moles) / Amount of carbon oxide supplied to the reactor (moles)) × 100 (B) C5 in Comparative Example 8 ＋ With the yield set to 1, C5 of the other examples and comparative examples ＋ Normalize the yield to C5 ＋ This was used to measure yield. The results are shown in Table 2.

[0120]

[0121] <Evaluation> As shown in Table 2, if the thermal conductivity of the ceramic substrate is 8 W / m·K or higher, and the porosity of the catalyst layer is 20% or higher, then C5 ＋ It can be seen that the yield (quantity) can be significantly improved.

[0122] The reactor according to the embodiment of the present invention can be used to produce various reaction products, and is particularly suitable for the continuous production of methane and hydrocarbons having 5 or more carbon atoms.

[0123] 1 Ceramic substrate 1a Honeycomb substrate 13 Partition wall 14 Cell 15 Gas flow path 2 Catalyst layer 100 Reactor

Claims

1. A reactor having a gas channel through which a raw material gas containing reactants is supplied, comprising: a ceramic substrate; and a catalyst layer disposed on the surface of the ceramic substrate so as to face the gas channel, wherein the catalyst layer contains a catalyst capable of promoting the chemical reaction of the reactants, the thermal conductivity of the ceramic substrate is 8 W / m·K or more, and the porosity of the catalyst layer is 20% or more.

2. The reactor according to claim 1, wherein the porosity of the catalyst layer is 75% or less.

3. The reactor according to claim 1, wherein the porosity of the catalyst layer is 25% or more.

4. The reactor according to any one of claims 1 to 3, wherein the thickness of the catalyst layer is 0.1 μm or more and 500 μm or less.

5. The reactor according to any one of claims 1 to 3, wherein the thickness of the catalyst layer is less than 300 μm.

6. The reactor according to any one of claims 1 to 3, wherein the thickness of the catalyst layer exceeds 20 μm.

7. The reactor according to any one of claims 1 to 3, wherein the thermal conductivity of the ceramic substrate is 100 W / m·K or more.

8. The reactor according to any one of claims 1 to 3, wherein the porosity of the ceramic substrate is 65% or less, and the average pore diameter of the ceramic substrate is 50 μm or less.

9. The reactor according to any one of claims 1 to 3, wherein the ceramic substrate is a honeycomb substrate having partitions that constitute a plurality of cells, and at least a portion of the plurality of cells includes the gas flow path.

10. The reactor according to claim 9, wherein the thickness of the partition wall exceeds 0.254 mm.

11. The reactor according to any one of claims 1 to 3, wherein the reactant comprises carbon oxide and hydrogen.

12. The reactor according to claim 11, wherein the raw material gas further comprises oxygen.

13. The reactor according to claim 11, wherein the catalyst is a methanation reaction catalyst.

14. The reactor according to claim 11, wherein the catalyst is a Fischer-Tropsch reaction catalyst.

15. The reactor according to any one of claims 1 to 3, wherein the ceramic substrate comprises Si and SiC.

16. The reactor according to any one of claims 1 to 3, wherein the catalyst contains a transition metal as an active ingredient.

17. The reactor according to claim 16, wherein the transition metal includes Co, Fe, Pt, Ru, Rh, Pd, Ni, Cu, Ag, Au, Ir, Os, Mn, Ta, Mo, Zn, Cr, or a combination thereof.

18. The reactor according to claim 16, wherein the catalyst further comprises a carrier supporting the transition metal, the carrier comprising cerium oxide, silicon oxide, zirconium oxide, yttrium oxide, aluminum oxide, magnesium oxide, titanium oxide, or a composite oxide thereof.

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