Methane production reactor

Abstract

To provide a methane production reactor enabling methane production with reduced energy consumption and superior methane conversion efficiency.SOLUTION: A methane production reactor according to an embodiment of the present invention comprises a honeycomb substrate and a catalyst layer. The honeycomb substrate includes partition walls defining a plurality of cells. The cells contain gas flow paths. The catalyst layer includes a methanation reaction catalyst for methanating by reacting carbon dioxide with hydrogen. The catalyst layer is provided on the surface of the partition walls so as to face the gas flow paths. The methanation reaction catalyst contains Ni as an active component and a cerium oxide support carrying the Ni. The honeycomb substrate contains cordierite. The cell density in the honeycomb substrate is 300 cpsi or more.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a methane production reactor. [Background technology]

[0002] In recent years, from the viewpoint of reducing the environmental load, studies have been conducted on recovering carbon dioxide and reusing it as a raw material for carbon compounds. For example, methanation, in which carbon dioxide is reacted with hydrogen to convert it into methane, has been proposed (see, for example, Patent Document 1). However, this type of methanation requires a large amount of energy to proceed with the reaction, and the methane conversion rate is insufficient, so various issues remain to be addressed before it can be put into practical use. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-196619 Summary of the Invention [Problem to be solved by the invention]

[0004] A primary object of the present invention is to provide a methane production reactor capable of producing methane with energy savings and an excellent methane conversion rate. [Means for solving the problem]

[0005] [1] A methane production reactor according to one embodiment of the present invention includes a honeycomb substrate and a catalyst layer. The honeycomb substrate includes partition walls that define a plurality of cells. The cells include gas channels. The catalyst layer includes a methanation catalyst for methanating carbon dioxide with hydrogen. The catalyst layer is provided on the surface of the partition walls so as to face the gas channels. The methanation catalyst includes Ni as an active component and a cerium oxide support supporting Ni. The partition walls include cordierite. The honeycomb substrate has a cell density of 300 cpsi or more. [2] In the reactor for producing methane according to the above item [1], the partition wall may have a plurality of pores. The average pore diameter of the partition wall may be 5 μm or more. [3] In the reactor for producing methane according to the above [1] or [2], the partition wall may have a plurality of pores. The porosity of the partition wall may be 30% or more. [4] In the reactor for producing methane according to any one of the above [1] to [3], the thickness of the partition wall may be 0.0635 mm or more. [Effects of the Invention]

[0006] According to an embodiment of the present invention, a methane production reactor capable of producing methane with low energy consumption and an excellent methane conversion rate can be realized. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic perspective view of a methane production reactor according to one embodiment of the present invention. [Figure 2] FIG. 2 is a schematic cross-sectional view of the methane production reactor of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to these embodiments. In addition, in order to clarify the description, the drawings may show the width, thickness, shape, etc. of each part more schematically than in the embodiment, but these are merely examples and do not limit the interpretation of the present invention.

[0009] A. Overview of the methane production reactor FIG. 1 is a schematic perspective view of a methane production reactor according to one embodiment of the present invention; FIG. 2 is a schematic cross-sectional view of the methane production reactor of FIG. The illustrated methane production reactor 100 includes a honeycomb substrate 1 and a catalyst layer 2. The honeycomb substrate 1 includes partition walls 12 that define a plurality of cells 13. The cells 13 include gas flow channels 14. The catalyst layer 2 includes a methanation catalyst for methanating carbon dioxide by reacting it with hydrogen. The catalyst layer 2 is provided on the surface of the partition wall 12 so as to face the gas flow channels 14. The methanation catalyst includes Ni as an active component and a cerium oxide carrier that supports Ni. The partition wall 12 includes cordierite. The cell density of the honeycomb substrate 1 is 300 cpsi or more, preferably 500 cpsi or more, more preferably 700 cpsi or more, and even more preferably 800 cpsi or more. On the other hand, the upper limit of the cell density of the honeycomb substrate 1 is typically 1200 cpsi. In this specification, the "cell density of the honeycomb substrate" refers to the cell density of the cross section in the length direction (direction in which the cells extend) of the honeycomb substrate, and "cpsi" refers to the cell density of 6.4516 cm 2 This refers to the number of cells per square inch. According to this configuration, the methanation catalyst contains Ni and a cerium oxide carrier, the honeycomb substrate contains cordierite, and the cell density of the honeycomb substrate is within this range. Therefore, when carbon dioxide and hydrogen are passed through the gas flow passages and supplied to the catalyst layer, the carbon dioxide and hydrogen can be efficiently brought into contact with the methanation catalyst, and the chemical reaction shown in formula (1) below can proceed smoothly. Because chemical reaction (1) is an exothermic reaction, the generated heat can be effectively used to promote the chemical reaction. As a result, methane can be produced with low energy consumption and at an excellent methane conversion rate. CO2 + 4H2 → CH4 + 2H2O (1)

[0010] B. Details of honeycomb substrate The honeycomb substrate 1 typically has a flow-through honeycomb structure. The honeycomb substrate 1 may have any appropriate shape (overall shape). Examples of the shape of the honeycomb substrate 1 include a cylindrical shape with a circular bottom, an elliptical cylindrical shape with an elliptical bottom, a rectangular prism with a polygonal bottom, and a cylindrical shape with an irregular bottom. In one embodiment, the honeycomb substrate 1 has a cylindrical shape. The outer diameter and length of the honeycomb substrate 1 can be appropriately set depending on the purpose. Although not shown, the honeycomb substrate 1 may have a hollow region at the center in a cross section perpendicular to the longitudinal direction.

[0011] In the illustrated example, the honeycomb substrate 1 includes an outer peripheral wall 11 and partition walls 12 located inside the outer peripheral wall 11. The outer peripheral wall 11 and the partition walls 12 may be formed integrally or separately. In the illustrated example, the outer peripheral wall 11 and the partition walls 12 are formed integrally.

[0012] The outer peripheral wall 11 has a cylindrical shape. The thickness of the outer peripheral wall 11 can be appropriately set depending on the application of the methane production reactor. The thickness of the outer peripheral wall 11 can be, for example, 1 mm to 10 mm, or can be, for example, 2 mm to 8 mm.

[0013] As described above, the partition walls 12 define a plurality of cells 13 . The cells 13 extend in the longitudinal direction (axial direction) of the honeycomb substrate 1 from a first end face 1a (inlet end face) to a second end face 1b (outlet end face) of the honeycomb substrate 1 (see FIG. 2). The cells 13 have any appropriate shape in a cross section perpendicular to the longitudinal direction of the methane production reactor 1. Examples of the cross-sectional shape of the cells include a triangle, a rectangle, a pentagon, a polygon having hexagons or more, a circle, and an ellipse. The cross-sectional shapes and sizes of the cells may all be the same, or at least some of them may be different. Among such cross-sectional shapes of the cells, a rectangle is preferred, and a square or rectangle is more preferred.

[0014] As will be described in detail later, gas flow channels 14 are formed inside the cells 13. The gas flow channels 14 are spaces formed inside the cells 13, and extend from the first end face 1a (inlet end face) to the second end face 1b (outlet end face) in the same manner as the cells 13. The cross-sectional shape of the gas flow channels 14 may be the same as that of the cells 13 described above, preferably a quadrangle, and more preferably a square or rectangle. The cross-sectional shapes and sizes of the gas flow channels 14 may all be the same, or at least some may be different.

[0015] In the illustrated example, the partition walls 12 have first partition walls 12a and second partition walls 12b that are perpendicular to each other, and the first partition walls 12a and the second partition walls 12b define a plurality of cells 13. The cross-sectional shape of the cells 13 is quadrangular except for the portions where the first partition walls 12a and the second partition walls 12b contact the outer peripheral wall 11. The configuration of the partition walls is not limited to the above-described partition walls 12. The partition walls may have first partition walls extending in the radial direction and second partition walls extending in the circumferential direction, which define a plurality of cells.

[0016] The thickness of the partition wall 12 can be set arbitrarily and appropriately. The thickness of the partition wall 12 is typically thinner than the thickness of the outer peripheral wall 11. The thickness of the partition wall 12 is, for example, 0.0254 mm (1.0 mil) or more, preferably 0.0635 mm (2.5 mil) or more. On the other hand, the thickness of the partition wall 12 is, for example, 0.508 mm (20 mil) or less, preferably 0.254 (10 mil) mm or less, more preferably 0.2032 (8.0 mil) mm or less, and even more preferably 0.127 (5.0 mil) mm or less. When the thickness of the partition wall is in this range, the mechanical strength of the methane production reactor can be made sufficient, and the cell density can be adjusted to the above-mentioned range. The thickness of the partition wall is measured, for example, by cross-sectional observation using an SEM (scanning electron microscope).

[0017] The partition wall 12 typically has a plurality of pores. The average pore diameter in the partition walls 12 can be appropriately set depending on the purpose. The average pore diameter in the partition walls 12 is, for example, 1 μm or more, and preferably 5 μm or more. On the other hand, the average pore diameter in the partition walls 12 is, for example, 20 μm or less, and preferably 15 μm or less. The average pore diameter is measured by, for example, mercury intrusion porosimetry. The porosity of the partition walls 12 can be appropriately set depending on the purpose. The porosity of the partition walls 12 is, for example, 15% or more, preferably 30% or more, more preferably 35% or more, and even more preferably 40% or more. On the other hand, the porosity of the partition walls 12 is, for example, 60% or less, preferably 55% or less, and more preferably 50% or less. The porosity can be measured by, for example, mercury intrusion porosimetry. When the average pore size and / or porosity of the partition walls 12 are within these ranges, the amount of methanation reaction catalyst supported on the partition walls can be improved.

[0018] The density of the partition walls 12 can be appropriately set depending on the purpose. For example, the density of the partition walls 12 is 1.7 g / cm 3 ~2.8g / cm 3 and preferably 1.8 g / cm 3 ~2.6g / cm 3 The density is measured by, for example, mercury intrusion porosimetry.

[0019] As described above, the partition walls 12 contain cordierite. The partition walls 12 may contain other ceramics in addition to cordierite. In other words, the partition walls 12 may be made of cordierite or may be made of cordierite and other ceramics. Other ceramics include, for example, silicon carbide, silicon-silicon carbide composites, mullite, alumina, spinel, silicon carbide-cordierite composites, lithium aluminum silicate, and aluminum titanate. The content of cordierite in the partition walls 12 is, for example, 65 mass % or more, and preferably 80 mass % or more. On the other hand, the upper limit of the content of cordierite in the partition walls 12 is typically 100 mass %.

[0020] C. Details of the catalyst layer The catalyst layer 2 is formed on the surface of the partition wall 12. In the methane production reactor 1, gas channels 14 are formed in the portions of the cross section of the cells 13 where the catalyst layer 2 is not formed (typically the central portion). The catalyst layer 2 may be formed on the entire inner surface of the partition wall 12 (i.e., so as to surround the gas channel 14) as in the illustrated example, or 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 12, the methane conversion rate can be stably improved.

[0021] As described above, the catalyst layer 2 contains a methanation catalyst containing Ni and a cerium oxide support. Ni can function as an active component that promotes the methanation reaction represented by the above formula (1). Ni may be contained in the methanation catalyst in a metallic state, or may be contained in the methanation catalyst as a nickel salt. In one embodiment, Ni is in a metallic state. The cerium oxide support is specifically CeO2, and supports the above-mentioned Ni. The Ni content is, for example, 0.01 to 50 parts by mass, and preferably 1 to 20 parts by mass, relative to 100 parts by mass of the cerium oxide support. When the Ni content is within this range, the methanation reaction can be stably promoted.

[0022] The methanation catalyst may have any appropriate shape. The methanation catalyst is typically in a particulate form. Hereinafter, the particulate methanation catalyst may be referred to as catalyst particles. In one embodiment, the catalyst layer 2 contains agglomerates of a plurality of catalyst particles. The agglomerates of a plurality of catalyst particles may form mesopores in the catalyst layer 2. The catalyst layer 2 may contain, in addition to the methanation catalyst, other components (for example, binder components such as aluminum oxide, silicon dioxide, titanium oxide, lanthanum oxide, zirconium oxide, niobium oxide, and neodymium oxide).

[0023] The content of the methanation catalyst in the catalyst layer 2 is, for example, 50% by mass or more, preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more. On the other hand, the upper limit of the content of the methanation catalyst in the catalyst layer 2 is typically 100% by mass. When the content of the methanation catalyst in the catalyst layer is within this range, the methane conversion rate can be improved more stably.

[0024] The average pore diameter in the catalyst layer 2 is, for example, 1 nm to 20 nm, and preferably 5 nm to 11 nm. The BET specific surface area of ​​the catalyst layer 2 is, for example, 20 m 2 / g~180m 2 / g, preferably 80m 2 / g~120m 2 / g.

[0025] D. Method of manufacturing a methane production reactor Next, we will explain the manufacturing method of the methane production reactor 100. The manufacturing method of the methane production reactor 100 includes the steps of preparing a honeycomb substrate 1 and forming a catalyst layer 2 on the partition walls 12 of the honeycomb substrate 1.

[0026] The honeycomb substrate 1 can be produced by the following method: First, a binder and water or an organic solvent are added as needed to a material powder containing cordierite powder, and the resulting mixture is kneaded to form a clay. The clay is then molded (typically by extrusion molding) into a desired shape, dried, and then fired as needed to produce the honeycomb substrate 1.

[0027] Next, the catalyst layer 2 is formed on the partition walls 12. The method for forming the catalyst layer 2 is not particularly limited, and any appropriate method may be adopted. In one embodiment, the step of forming the catalyst layer 2 includes, in order, a step of preparing catalyst particles; a step of preparing a catalyst slurry in which the catalyst particles are dispersed; and a step of applying the catalyst slurry onto the partition walls 12.

[0028] In the step of preparing catalyst particles, for example, a carrier dispersion liquid in which cerium oxide particles are dispersed and a nickel salt solution in which a nickel salt is dissolved are prepared.

[0029] To prepare the carrier dispersion, cerium oxide particles are added to a dispersion medium and stirred. The primary particle diameter of the cerium oxide particles is, for example, 1 μm to 10 μm. The amount of cerium oxide particles added is, for example, 5 to 30 parts by mass with respect to 100 parts by mass of the dispersion medium. Any suitable solvent that does not dissolve cerium oxide particles can be used as the dispersion medium. Examples of the dispersion medium include water and alcohols. The dispersion medium can be used alone or in combination. Of the dispersion mediums, water is preferred.

[0030] To prepare the nickel salt solution, the nickel salt is added to a solvent and stirred. Examples of nickel salts include nickel nitrate, nickel acetate, nickel sulfate, and nickel oxalate, and preferably nickel nitrate. The nickel salts may be used alone or in combination. The amount of nickel salt added is, for example, 0.1 to 1.5 parts by mass in terms of nickel weight per 100 parts by mass of the solvent. Examples of the solvent include the same dispersion media as those described above. The solvents can be used alone or in combination. Among the solvents, the same dispersion media as those used in the carrier dispersion liquid are preferred.

[0031] Next, the nickel salt solution is added to the carrier dispersion and stirred, thereby preparing a mixed solution of the carrier dispersion and the nickel salt solution. The mixing ratio of the carrier dispersion and the nickel salt solution can be adjusted arbitrarily and appropriately so that the Ni content in the produced methanation catalyst falls within the above range.

[0032] The mixture is then heated with stirring to evaporate the dispersion medium and the solvent, thereby obtaining a solid. The solid is then heated. The heating temperature of the solid material is, for example, 300°C to 700°C, and preferably 400°C to 600°C or less. The heating time for the solid material is, for example, 1 hour to 10 hours, and preferably 2 hours to 4 hours. The solid material may be heated in the atmosphere or in a reducing atmosphere (typically, a hydrogen atmosphere), and is preferably heated in the atmosphere. In this way, methanation reaction catalyst particles (catalyst particles) are prepared.

[0033] In the step of preparing the catalyst slurry, catalyst particles are added to a dispersion medium and stirred. Any suitable solvent that does not dissolve the catalyst particles can be used as the dispersion medium. Examples of the dispersion medium include water and alcohols. The dispersion medium can be used alone or in combination. Among the dispersion mediums, water is preferred. As a result, the catalyst particles are dispersed in the dispersion medium to prepare a catalyst slurry. The catalyst particle content in the catalyst slurry is, for example, 5% by mass to 50% by mass, and preferably 10% by mass to 30% by mass. When the catalyst particle content in the catalyst slurry is within this range, the catalyst slurry can be smoothly applied onto the partition walls, and a catalyst layer can be stably formed.

[0034] Next, in the step of applying the catalyst slurry, the catalyst slurry is applied onto the partition walls 12 of the honeycomb substrate 1 by any appropriate method. In one embodiment, the honeycomb substrate 1 is immersed in the catalyst slurry. This is a simple method, but it is possible to sufficiently apply the catalyst slurry to the surfaces of the partition walls. However, the application of the catalyst slurry is not limited to this. For example, the catalyst slurry may be circulated through the cells 13 of the honeycomb substrate 1. This method also allows the catalyst slurry to be applied onto the partition walls.

[0035] Next, the coating of the catalyst slurry formed on the partition walls 12 is dried at any appropriate heating temperature, as required. As a result, the catalyst layer 2 is formed on the surface of the partition walls 12. The above-mentioned steps of applying the catalyst slurry and drying the coating film may be repeated multiple times until the thickness of the catalyst layer 2 reaches a desired range.

[0036] In this manner, the methane production reactor 100 including the honeycomb substrate 1 and the catalyst layer 2 is manufactured.

[0037] C. Methane Production Methods The above-described methane production reactor 100 is a honeycomb structure for a methanation reaction, and can be suitably used for producing methane by reacting carbon dioxide with hydrogen. In the methane production reactor 100, a raw material gas containing carbon dioxide and hydrogen is supplied to the catalyst layer 2, thereby producing methane.

[0038] In one embodiment, the methane production reactor 100 is heated to a predetermined methanation reaction initiation temperature, and the raw material gas is supplied to the gas flow passage 14 of the methane production reactor 100. The methanation reaction initiation temperature is, for example, 200°C to 300°C. As a result, the raw material gas is supplied to the catalyst layer 2 at the methanation reaction initiation temperature, and the methanation reaction of the above formula (1) starts.

[0039] The content of carbon dioxide in the raw material gas is, for example, 1.0 to 20% by volume, and preferably 5.0 to 15% by volume. The hydrogen content in the raw material gas is, for example, 4.0% by volume to 80% by volume, and preferably 20% by volume to 60% by volume. In one embodiment, the feed gas contains oxygen in addition to carbon dioxide and hydrogen. When the feed gas contains oxygen, the chemical reaction shown in the following formula (2) can proceed when the hydrogen and oxygen come into contact with the methanation catalyst. Because the chemical reaction (2) is an exothermic reaction, the generated reaction heat can be effectively utilized to proceed with the methanation reaction of the above formula (1). O2 + 2H2 → 2H2O (2) The oxygen content in the raw material gas is, for example, 0.5% to 10% by volume, and preferably 1.0% to 5.0% by volume. Furthermore, the source gas may contain nitrogen as the balance. Any appropriate value can be adopted as the flow rate of such a source gas, and the flow rate of the source gas is, for example, 500 mL / min to 1500 mL / min.

[0040] When the raw material gas is supplied to the catalyst layer 2 at the methanation reaction initiation temperature and the methanation reaction of formula (1) begins, the methanation reaction can be continued by utilizing the heat of reaction. Therefore, external heating of the methane production reactor 100 may be stopped. When external heating of the methane production reactor 100 is stopped, the methane production reactor 100 can be maintained at, for example, 300°C to 500°C by the heat of reaction. In other words, automated methanation can be performed by using the methane production reactor 100. This allows for energy savings in methane production. Furthermore, since the methane production reactor 100 can be maintained at a temperature suitable for the methanation reaction without providing any thermal insulation material for the methane production reactor 100, the methane production apparatus can be designed compactly.

[0041] As a result, methane-containing gas is continuously discharged from the gas passage 14 of the methane production reactor 100. The methane-containing gas contains at least methane, and may contain unreacted raw material gas remaining. In such methane production, the cell density in the methane production reactor 100 is 300 cpsi or more, so that methane can be produced with an excellent methane conversion rate. The higher the methane conversion rate, the more preferable, and is, for example, 65% or more, preferably 70% or more, more preferably 73% or more, and further preferably 75% or more. [Example]

[0042] The present invention will be specifically explained below with reference to examples, but the present invention is not limited to these examples.

[0043] <Examples 1 to 4 and Comparative Example 1> <<Preparation of honeycomb substrate>> A clay containing cordierite was extruded and then dried to prepare a honeycomb substrate as 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 had partition walls that defined a plurality of cells and an outer peripheral wall that surrounded the partition walls. The cross-sectional shape of the cells was rectangular. Table 1 shows the cell density, partition wall thickness, average pore diameter of the partition walls, and porosity of the partition walls in the honeycomb substrate. <<Preparation of methanation 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 resulted in a dispersion of cerium oxide particles. Nickel (II) nitrate hexahydrate was also dissolved in distilled water to obtain a nickel nitrate aqueous solution. Next, a nickel nitrate aqueous solution was added to the cerium oxide particle dispersion and stirred at room temperature (23°C) for 2 hours. The mixture of the dispersion and aqueous solution was then heated to 80°C with stirring to evaporate the water. The remaining solid was then heated at 500°C for 3 hours. This resulted in methanation reaction catalyst particles (hereinafter referred to as catalyst particles). The catalyst particles contained nickel (Ni) and cerium (IV) oxide supporting nickel (Ni). The Ni content in the methanation reaction catalyst particles was 10 parts by mass relative to 90 parts by mass of cerium oxide. <<Preparation of catalyst layer>> The obtained catalyst particles were dispersed in distilled water to prepare a catalyst slurry. The catalyst particle content in the catalyst slurry was 10 mass%. Next, the honeycomb substrate prepared above was immersed in the catalyst slurry for 10 seconds under normal pressure (0.1 MPa) and room temperature (23°C). After that, the honeycomb substrate was pulled out of the catalyst slurry. In this way, the catalyst slurry was applied to the surfaces of the partition walls. Then, the catalyst slurry applied to the surfaces of the partition walls was heated and dried at 100°C for 120 minutes. The above immersion and drying were repeated to form a catalyst layer on the surfaces of the partition walls. The catalyst layer contained aggregates of catalyst particles. The amount of catalyst particles supported per unit area of ​​the partition walls is shown in Table 1. In this manner, a methane production reactor including a honeycomb substrate and a catalyst layer was manufactured.

[0044] <Auto-methanation test> The methane production reactor obtained in each example and comparative example was inserted into a reaction tube with an inner diameter of 21 mm. As a pretreatment for the reaction, the methane production reactor was heated to 500°C using an electric furnace installed around the outer periphery of the reaction tube, and hydrogen gas was introduced into the reaction tube for reduction treatment. Thereafter, the temperature of the electric furnace was lowered to 200°C, and a mixed gas consisting of 10% by volume of carbon dioxide, 3% by volume of oxygen, 46% by volume of hydrogen, and the remainder nitrogen was introduced into the reaction tube as a raw material gas. The flow rate of the raw material gas introduced into the reaction tube was set to 1000 mL / min. As a result, the raw material gas passed through each gas flow path provided in the methane production reactor, and a methane-containing gas flowed out from the reaction tube. Furthermore, carbon monoxide produced by a side reaction was not confirmed. While the feed gas was flowing through the reaction tube, the set temperature of the electric furnace was gradually lowered, and finally the heating by the electric furnace was stopped. Note that the temperature of the methane production reactor was maintained at about 400°C due to the heat of reaction even after the heating by the electric furnace was stopped. After the heating of the electric furnace was stopped and the reaction heat stabilized, the concentrations of carbon dioxide and methane in the methane-containing gas flowing out of the reaction tube were measured using a gas chromatograph-thermal conductivity detector (GC-TCD). Using the measurement results (carbon dioxide concentration and methane concentration in the methane-containing gas), the conversion rate (%) from carbon dioxide to methane was calculated using the following formula (I). The results are shown in Table 1. Methane conversion rate (%) = (methane concentration / sum of carbon dioxide concentration and methane concentration) × 100 (I)

[0045] [Table 1]

[0046] <Evaluation> As shown in Table 1, it can be seen that in Examples where the cell density is 300 cpsi or more, the methane conversion rate can be significantly improved. [Industrial Applicability]

[0047] The methane production reactor according to the embodiment of the present invention can be suitably used in a methane production apparatus that produces methane by reacting carbon dioxide with hydrogen. [Explanation of symbols]

[0048] 1. Honeycomb substrate 12 Bulkhead 13 cells 14 Gas flow path 2 Catalyst layer 100 Methane production reactor

Claims

1. a honeycomb substrate having partition walls defining a plurality of cells including gas flow paths; a catalyst layer including a methanation reaction catalyst for methanating carbon dioxide with hydrogen, the catalyst layer being provided on a surface of the partition wall so as to face the gas flow path; The methanation reaction catalyst includes Ni as an active component and a cerium oxide support supporting Ni, the partition walls contain cordierite, A reactor for producing methane, wherein the honeycomb substrate has a cell density of 300 cpsi or more.

2. the partition wall has a plurality of pores, 2. The reactor for producing methane according to claim 1, wherein the partition walls have an average pore diameter of 5 μm or more.

3. the partition wall has a plurality of pores, 3. The reactor for methane production according to claim 1, wherein the partition walls have a porosity of 30% or more.

4. 3. The reactor for methane production according to claim 1, wherein the partition wall has a thickness of 0.0635 mm or more.

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