Method for producing compound by gas-solid catalytic reaction, and reactor

Abstract

Disclosed is a method for producing a compound, the method comprising generating a target compound from a raw material gas by a gas-solid catalytic reaction in a reaction tube that houses a structured catalyst. The structured catalyst has a conductive substrate extending along a constant axis and a catalyst layer provided on the substrate. The substrate includes a plate-like section that extends along the axis while twisting in a direction of rotation about the axis. The structured catalyst is inserted into the reaction tube oriented so that the axis is parallel to the longitudinal direction of the reaction tube. The raw material gas is introduced into the reaction tube while applying current to the substrate.

Description

Method for producing compounds by gas-solid catalytic reaction and reactor

[0001] The present disclosure relates to a method and reactor for producing compounds by gas-solid catalytic reactions.

[0002] Conventionally, studies have been conducted on the production of various compounds from raw materials in the gas phase by gas-solid catalytic reactions in the presence of a catalyst provided on a substrate (for example, Patent Document 1, Non-Patent Document 1).

[0003] Meanwhile, Patent Document 2 discloses an electric heater for an internal combustion engine exhaust purification system that has honeycomb-shaped heating element layers, in which electricity is applied to each heating element to achieve uniform heat generation in a direction perpendicular to the gas flow direction. Patent Documents 3 and 4 disclose an electrically heated catalyst having a ceramic carrier and a surface electrode disposed on the surface of the ceramic carrier. Patent Document 5 discloses a catalytic reaction device having catalyst bodies arranged in multiple stages along the flow direction of the treated fluid, in which the catalyst bodies are made of coiled wire and a control device is provided whose circuit controls the amount of electricity applied to the heater section of each catalyst body to independently control the temperature of each catalyst body. Patent Document 5 also discloses that when the performance of the most upstream catalyst body deteriorates, the current application point is shifted to the next downstream catalyst body.

[0004] JP 2020-033280 A JP 8-218846 A JP 2012-106164 A JP 2012-106199 A JP 2015-098408 A

[0005] Chem. Lett. 2019, 48, 441-444

[0006] When conventional catalysts with a mesh structure such as a honeycomb are used for exothermic reactions, the concentration of heat in the center of the mesh structure can cause temperature unevenness, which can reduce reaction efficiency.

[0007] The present disclosure relates to more efficient production of compounds in gas-solid catalytic reactions in the presence of a catalyst disposed on a substrate.

[0008] The present disclosure includes the following. [1] A method for producing a compound by a gas-solid catalytic reaction, comprising generating a target compound from a raw material gas by a gas-solid catalytic reaction in a reaction tube containing a structure catalyst, wherein the structure catalyst has a conductive substrate extending along a certain axis and a catalyst layer provided on the substrate, the substrate has a plate-like portion extending along the axis while twisting in a direction rotating around the axis, the structure catalyst is inserted into the reaction tube with the axis parallel to the longitudinal direction of the reaction tube, and the raw material gas is introduced into the reaction tube while current is being applied to the substrate. [2] The method according to [1], wherein current is applied to the substrate along the longitudinal direction of the reaction tube by conductors connected to both ends of the structure catalyst and a power source. [3] The method according to [1] or [2], wherein one structure catalyst is contained in one reaction tube. [4] The method according to [1] or [2], wherein a plurality of the structure catalysts are accommodated in one reaction tube, and the amount of electricity applied to the base material in the plurality of the structure catalysts is collectively controlled while the raw material gas is being introduced into the reaction tube. [5] The method according to any one of [1] to 4, wherein, when the length of the structure catalyst is L and the maximum width of the structure catalyst in a direction perpendicular to the axis is W, the ratio L / W is 2 or more and 100 or less. [6] A reaction apparatus comprising: a reaction tube; a structure catalyst accommodated in the reaction tube; a power source; and a conductor connected to the power source, wherein the structure catalyst has a conductive base material extending along a certain axis and a catalyst layer provided on the base material, the base material having a plate-like portion extending along the axis while twisting in a direction rotating around the axis, the structure catalyst is inserted into the reaction tube with the axis parallel to the longitudinal direction of the reaction tube, and the conductors are connected to both ends of the structure catalyst so as to apply electricity to the base material. [7] The reaction apparatus according to [6], wherein one of the structure catalysts is accommodated in one of the reaction tubes. [8] The reaction apparatus according to [6], wherein a plurality of the structure catalysts are accommodated in one of the reaction tubes, and the reaction apparatus further comprises a control unit configured to collectively control the amount of current passing through the base material in the plurality of the structure catalysts.[9] The length of the structure catalyst is L, and the maximum width of the structure catalyst in a direction perpendicular to the axis is W, and the ratio L / W is 2 or more and 100 or less, [6] to [8]. The reaction apparatus according to any one of [6] to [8].

[0009] In a gas-solid catalytic reaction in the presence of a catalyst provided on a substrate, a compound can be produced more efficiently.By combining a structure catalyst having a substrate with a plate-shaped portion extending along the axis while twisting in the direction of rotation around the axis, and current passing through the substrate, the temperature of the structure catalyst can be easily made uniform and the efficiency of the gas-solid catalytic reaction can be improved without the need for installing an insulating portion or adjusting the current passing position.

[0010] 2 is a schematic diagram showing an example of a reaction apparatus; FIG. 3 is a schematic diagram showing an example of a structure catalyst; FIG. 4 is an end view taken along line III-III in FIG. 2; ２ 1 is a graph showing the relationship between the conversion rate and the power required for energizing the structure catalyst or heating the electric furnace. 2 is an image showing the results of measuring the surface temperature of the structure catalyst during a reaction test by thermography. 3 is a graph showing the relationship between the ethanol conversion rate or the amount of hydrogen produced and the temperature of the electric furnace in an ethanol steam reforming test. 4 is a graph showing the relationship between the CO and CO in an ethanol steam reforming test. ２ 1 is a graph showing the relationship between the selectivity of conversion to CO, methane, or acetaldehyde and the temperature of the electric furnace. 2 is a graph showing the relationship between the conversion rate of ethanol or the amount of hydrogen produced and the temperature of the electric furnace in an ethanol steam reforming test. 3 is a graph showing the relationship between the selectivity of conversion to CO, methane, or acetaldehyde and the temperature of the electric furnace in an ethanol steam reforming test. ２ 1 is a graph showing the relationship between the selectivity of conversion to ethane, methane, or acetaldehyde and the temperature of the electric furnace.

[0011] The present invention is not limited to the following examples.

[0012] An example of a method for producing a compound according to the present disclosure includes producing a target compound from a raw material gas by a gas-solid catalytic reaction in a reaction tube provided with a structure catalyst. Fig. 1 is a schematic diagram showing an example of a reaction apparatus used for producing a compound. The reaction apparatus 10 shown in Fig. 1 includes a cylindrical reaction tube 1, a structure catalyst 3 housed in the reaction tube 1, a gas inlet 5A and a gas outlet 5B provided at both ends of the reaction tube 1, a power source 7, and a conductor 8 connected to the power source 7. A raw material gas G containing a starting material is supplied to the reaction tube 1. ０ is introduced into the reaction tube 1 from the gas inlet 5A. In the raw material gas in the reaction tube 1, a gas-solid catalytic reaction proceeds due to the catalytic action of the structural catalyst 3. A product gas G containing the target compound, which is the product of the gas-solid catalytic reaction, is １ is discharged from the gas outlet 5B.

[0013] FIG. 2 is a schematic diagram showing an example of a structure catalyst, and FIG. 3 is an end view taken along line III-III in FIG. 2. The structure catalyst 3 shown in FIGS. 2 and 3 has a conductive substrate 30 having a portion extending along a certain axis X, and a catalyst layer 35 covering the entire outer surface S of the substrate 30. In the substrate 30, the axis X is also a center line along the longitudinal direction of the substrate 30. The catalyst layer 35 does not need to cover the entire outer surface of the substrate 30. The substrate 30 as a whole is composed of a plate-like portion extending along the axis X while twisting in a direction rotating around the axis X. In this specification, such a shape may be referred to as a "spiral type." In the reaction apparatus 10 of FIG. 1, the structure catalyst 3 is inserted into the reaction tube 1 with the axis X parallel to the longitudinal direction of the reaction tube 1. In the example of FIG. 1, one structure catalyst 3 is accommodated in one reaction tube 1. Two or more structure catalysts 3 may be inserted in series into one reaction tube.

[0014] Two conductors 8 are electrically connected to both ends of the structure catalyst 3. The structure catalyst 3 is heated by applying electricity to the substrate. The two conductors 8 allow electricity to be applied to the substrate 30 along the longitudinal direction of the reaction tube 1. In conventional methods using external heating, the temperature of the portion of the structure catalyst 3 on the gas inlet 5A side rises excessively, while the temperature of the portion of the structure catalyst on the gas outlet 5B side (downstream) does not rise sufficiently, which may hinder the improvement of the overall reaction efficiency. The synergistic effect of the combination of efficient flow of the raw material gas over the spiral structure catalyst 3 in the longitudinal direction of the reaction tube and heating by applying electricity to the substrate allows the structure catalyst 3 to be heated so as to achieve a highly uniform temperature distribution in the longitudinal direction of the structure catalyst 3 or in the direction of the axis X. Therefore, the gas-solid catalytic reaction can proceed efficiently at an appropriate temperature throughout the structure catalyst 3.

[0015] The power of the current supplied to the substrate is adjusted so that the structure catalyst 3 is heated to a temperature at which the gas-solid catalytic reaction proceeds appropriately. Compared to heating the reaction tube 1 and the structure catalyst 3 solely by supplying heat from a heat source provided outside the reaction tube 1, the gas-solid catalytic reaction can proceed efficiently with less power. For example, the power supplied to the substrate is adjusted in the range of 3 watts to 500 kilowatts. The temperature of the structure catalyst 3 reached by current supply may be any temperature at which the gas-solid catalytic reaction proceeds appropriately, and may be, for example, in the range of 0°C to 1500°C, 10°C to 1400°C, or 20°C to 1200°C. In the case of a methanation reaction, the temperature of the structure catalyst 3 reached by current supply may be 10°C to 600°C. In the case of a dehydrogenation reaction, the temperature of the structure catalyst 3 reached by current supply may be 10°C to 800°C. In the case of a hydrogenation reaction, the temperature of the structure catalyst 3 reached by current supply may be 10°C to 600°C. In the case of a steam reforming reaction, the temperature of the structure catalyst 3 reached by energization may be 10°C or higher and 1200°C or lower. In the case of a dry reforming reaction, the temperature of the structure catalyst 3 reached by energization may be 10°C or higher and 1200°C or lower. In the case of a water gas shift reaction, the temperature of the structure catalyst 3 reached by energization may be 10°C or higher and 800°C or lower. In the case of a reverse shift reaction, the temperature of the structure catalyst 3 reached by energization may be 10°C or higher and 1000°C or lower. In the case of an ammonia synthesis reaction, the temperature of the structure catalyst 3 reached by energization may be 10°C or higher and 800°C or lower. In the case of an ammonia decomposition reaction, the temperature of the structure catalyst 3 reached by energization may be 10°C or higher and 1200°C or lower. In the case of a denitrification reaction, the temperature of the structure catalyst 3 reached by energization may be 10°C or higher and 1000°C or lower.

[0016] The conductors 8 are fixed to both ends of the structural catalyst 3 so as to be electrically conductive to the substrate. The conductors 8 may be fixed to the structural catalyst 3 so as to be in direct contact with the conductive substrate, or they do not necessarily have to be in direct contact with the substrate as long as appropriate electrical conduction is ensured. The method for fixing the conductors 8 is not particularly limited. For example, the conductors 8 can be fixed to the structural catalyst 3 by welding, fasteners, adhesives, or a combination thereof. The power source 7 and the conductors 8 can be those normally used for electrical conduction. The conductors 8 may include, for example, copper wires.

[0017] When a plurality of structural catalysts 3 are accommodated in one reaction tube, the raw material gas G ０ During the entire period in which the raw material gas G is introduced, the amount of electricity to the substrate 30 in the plurality of structure catalysts 3 may be controlled collectively or independently. According to the method according to the present disclosure, the amount of electricity to the plurality of structure catalysts 3 is controlled independently, and a high temperature uniformity can be easily maintained without the need to move the position of electricity during the reaction. For example, when the raw material gas G is introduced into the reaction tube 1, ０ While the raw material gas G is being introduced, the same voltage may be applied to the plurality of structural catalysts 3 at the same time to collectively control the amount of current. Alternatively, the plurality of structural catalysts 3 may be connected in series via a conductor, and the raw material gas G may be introduced into the reaction tube 1. ０ While the catalyst is being introduced, a single power source may be used to apply a voltage to the plurality of structural catalysts 3, thereby controlling the energization collectively. A control unit configured to collectively control the amount of energization of the substrates 30 in the plurality of structural catalysts 3 may be provided.

[0018] In addition to applying electricity to the substrate, the reaction tube 1 or the structural catalyst 3 may be heated by supplying heat from a heat source provided outside the reaction tube 1. In particular, when the gas-solid catalytic reaction is an endothermic reaction, the gas-solid catalytic reaction can proceed more efficiently by combining heating by an external heat source with applying electricity to the substrate. The heat source is usually provided around the reaction tube. The heat source is not particularly limited, and may be, for example, an electric heater that generates heat by resistance heating or the like, or a heat medium heated to a predetermined temperature. The temperature of the heat source can be adjusted, for example, within a range of 5°C to 1000°C, taking into account the type of gas-solid catalytic reaction, etc.

[0019] The length of the reaction tube 1 may be, for example, 10 to 20,000 mm. The inner diameter of the reaction tube 1 may be, for example, 5 to 200 mm. A plurality of reaction tubes may be provided.

[0020] The gas-solid catalytic reaction may be any reaction that can produce a target product from a gas-phase raw material in the presence of the structural catalyst 3, and examples thereof include a methanation reaction, a dehydrogenation reaction, a hydrogenation reaction, a steam reforming reaction, a dry reforming reaction, a water gas shift reaction, a reverse shift reaction, an ammonia synthesis reaction, an ammonia decomposition reaction, and a denitration reaction. An example of an exothermic reaction is a methanation reaction. A methanation reaction produces methane from carbon dioxide and hydrogen in a raw material gas containing carbon dioxide and water. An example of an endothermic reaction is a steam reforming reaction. A steam reforming reaction produces carbon monoxide and hydrogen from a raw material gas containing hydrocarbons (e.g., methane) or alcohols (e.g., ethanol) and water.

[0021] The substrate 30 or its plate-like portion may be a molded body of a conductive material. For example, the substrate 30 or its plate-like portion may be a molded body of a metal, ceramic, or carbon material. The substrate 30 may be a molded body of a metal selected from aluminum, nickel, nickel-chromium alloy, copper, noble metal, and stainless steel, or a molded body of silicon carbide. In terms of processability into a spiral shape, the substrate 30 may be a molded body of a metal.

[0022] The substrate 30 may have a porous metal portion including its outer surface. The entire substrate 30 may be a porous metal portion, or the substrate 30 may have a porous metal portion located at the outermost layer and a non-porous internal structure provided inside the porous metal portion. When a porous metal portion is provided, the catalyst layer 35 may be attached to the porous metal portion. A portion of the catalyst layer 35 may penetrate into the pores of the porous metal portion. In other words, the catalyst layer 35 may have a portion that penetrates into the pores of the porous metal portion and a portion that is provided outside the porous metal portion.

[0023] In the structural catalyst 3, when the amount of catalyst layer 35 attached to the substrate 30 is large, the gas-solid catalytic reaction tends to proceed particularly efficiently. For example, the mass of the catalyst layer 35 attached to the substrate 30 may be 1 g or more and 1000 g or less per 1 L of substrate volume. The mass of the catalyst layer 35 attached to the substrate 30 may be 10 g or more, 20 g or more, 30 g or more, 40 g or more, or 50 g or more per 1 L of substrate volume. A substrate 30 having a porous metal portion makes it easy to increase the amount of catalyst layer 35 attached. The volume of the substrate here includes the volume of the pores in the porous metal portion. Note that, in this specification, the volume of the substrate refers to the volume of the cylindrical space formed by the substrate processed into a spiral shape. For example, the volume of a spiral-shaped substrate with a width of 100 mm and a length of 100 mm is 0.785 L.

[0024] The porous metal portion may include pores that communicate with each other. The average pore size of the porous metal portion may be, for example, 1 μm or more and 100 mm or less. The average pore size here is the average value of the pore sizes of the multiple pores that constitute the porous metal portion. The maximum width of the pores can be considered to be the pore size of the pores. The average pore size can be, for example, the average value of the pore sizes of any 10 or more pores. The average pore size of the porous metal portion may be 5 μm or more, 10 μm or more, 50 μm or more, 0.1 mm or more, 0.2 mm or more, 0.3 mm or more, or 0.4 mm or more, or may be 50 mm or less, 40 mm or less, 30 mm or less, 20 mm or less, 10 mm or less, 5 mm or less, 4 mm or less, 3 mm or less, 2 mm or less, or 1 mm or less.

[0025] The porosity of the porous metal portion may be, for example, 40% or more and 99% or less. The porosity is the ratio of the volume of pores to the total volume of the porous metal portion including the volume of pores. The porosity of the porous metal portion may be 45% or more, 50% or more, 55% or more, 60% or more, 65% or more, 70% or more, 75% or more, 80% or more, or 90% or more, or may be 95% or less, 90% or less, 85% or less, 80% or less, 75% or less, 70% or less, 65% or less, or 60% or less.

[0026] The porous metal portion of the substrate 30 can be a formed body of any metal. The porous metal portion may be a metal formed body containing, for example, nickel, chromium, tin, aluminum, iron, tungsten, iron, cobalt, copper, zirconium, titanium, silicon, magnesium, stainless steel, or an alloy, oxide, or carbide containing any of these. A porous metal portion containing nickel or a nickel alloy can contribute to further improving the efficiency of the gas-solid catalytic reaction.

[0027] The length L of the substrate 30 or the structural catalyst 3 in the direction along the axis X, the maximum width W in the direction perpendicular to the axis X, and the thickness T of the plate-like portion are appropriately set depending on the shape, size, etc. of the reaction tube. The length L may be, for example, 5 mm or more or 40 mm or more, and may be 2000 mm or less or 5000 mm or less. The thickness of the substrate 30 (plate-like portion) or the structural catalyst 3 may be, for example, 0.1 mm or more and 100 mm or less. The ratio L / W may be 2 or more and 100 or less. The ratio L / W may be 2 or more, 4 or more, 6 or more, 8 or more, or 10 or more, or may be 100 or less, 95 or less, 90 or less, 85 or less, 80 or less, or 75 or less. In the case of a method including passing electricity through the substrate 30, even when the ratio L / W is large, the structural catalyst 3 can be heated with a uniform temperature distribution throughout the entire longitudinal direction.

[0028] The maximum width W of the substrate 30 (plate-like portion) or the structural catalyst 3 is set so that the structural catalyst 3 can be inserted into the reaction tube 1. If the maximum width W is close to the inner diameter of the reaction tube, it is advantageous in terms of making the apparatus compact, and the efficiency of heat transfer from the reaction tube can be increased. Specifically, the ratio of the maximum width W to the inner diameter of the reaction tube 1 may be 0.85 or more or 0.90 or more, or may be 1.0 or less or 0.95 or less. The maximum width W may be, for example, 2 mm or more or 5 mm or more, or 500 mm or less or 100 mm or less.

[0029] In the case of the structural catalyst exemplified in FIG. 2 , the plate-shaped portion of the substrate is twisted in one direction around the axis X, but the shape of the substrate (plate-shaped portion) is not limited to this and can be modified as appropriate. For example, when viewed from the direction along the axis X, the substrate (plate-shaped portion) may include a portion twisted in the clockwise direction and a portion twisted in the counterclockwise direction. The period of twist does not need to be constant and may vary. From the viewpoint of efficient mixing of gas, the substrate (plate-shaped portion) may be a static mixer element. As will be understood by those skilled in the art, a substrate including twisted plate-shaped bodies can be obtained by processing a molded body using a conventional method.

[0030] In the portion (spiral portion) of the substrate 30 (plate-shaped portion) that extends along the axis X while twisting in the direction of rotation about the axis X, the pitch, which is the length in the direction of the axis X of the portion that makes one rotation about the axis X, is P, and the maximum width in the direction perpendicular to the axis X of the portion that makes one rotation about the axis X is W. The twist ratio P / W may be 1.5 or more and 10.0 or less. When the twist ratio is within this range, high reaction efficiency is more easily achieved. From the same perspective, the twist ratio P / W may be 1.6 or more, 1.7 or more, or 1.8 or more, or may be 9.5 or less, 9.0 or less, 8.5 or less, 8.0 or less, 7.5 or less, 7.0 or less, 6.5 or less, 6.0 or less, 5.5 or less, or 5.0 or less. When the spiral portion is twisted to make two or more revolutions about the axis X, the twist ratio P / W per revolution may be substantially constant, substantially constant, or may vary. When the twist ratio P / W per revolution varies, the average twist ratio P / W over the entire spiral portion may be within the above range.

[0031] The catalyst layer 35 contains a catalyst that promotes the gas-solid catalytic reaction. The type of catalyst can be selected depending on the type of gas-solid catalytic reaction, etc. For example, the catalyst may contain one or more catalytic metals selected from the group consisting of nickel, ruthenium, rhodium, potassium, calcium, sodium, and iridium. These catalytic metals function as catalysts that promote, for example, a methanation reaction.

[0032] The catalyst constituting the catalytic layer 35 may contain one or more catalytic metals selected from transition metals of Groups 4 to 14. These catalytic metals function as catalysts that promote the steam reforming reaction, for example. For example, the catalyst for promoting the steam reforming reaction may contain one or more catalytic metals selected from the group consisting of nickel, copper, cobalt, iron, platinum, palladium, rhodium, ruthenium, iridium, silver, and gold.

[0033] The catalyst constituting the catalyst layer 35 is a mixture of one or more catalytic metals selected from the group consisting of nickel, magnesium, zirconium, silicon, titanium, aluminum, ruthenium, and rhodium, and nickel oxide (NiO ２), aluminum oxide (Al ２ O ３ ), zirconium oxide (ZrO ２ ), silicon oxide (SiO ２ ), magnesium oxide (MgO), and titanium oxide (TiO ２ ) may contain one or more metal oxides selected from the group consisting of: copper, nickel, zinc, aluminum, ruthenium, platinum, rhodium, silver, chromium, and magnesium. A catalyst containing these components functions as a catalyst for promoting a dry reforming reaction, for example. The catalyst constituting the catalyst layer 35 may contain one or more catalytic metals selected from the group consisting of copper, nickel, zinc, aluminum, ruthenium, platinum, rhodium, silver, chromium, and magnesium, and zinc oxide (ZnO), aluminum oxide (Al ２ O ３ ), chromium oxide (Cr ２ O ３ ), silicon oxide (SiO ２ ), and magnesium oxide (MgO). A catalyst containing these components functions as a catalyst for promoting, for example, the water gas shift reaction and the reverse shift reaction.

[0034] The catalyst constituting the catalyst layer 35 may include a carrier that supports a catalytic metal. The carrier contains, for example, a metal oxide containing at least one metal element selected from cerium, zirconium, yttrium, aluminum, silicon, and magnesium. The metal oxide may contain two or more metal elements selected from cerium, zirconium, yttrium, aluminum, silicon, and magnesium. The carrier may be cerium oxide (CeO ２ ), zirconium oxide (ZrO ２ ), yttrium oxide (Y ２ O ３ ), aluminum oxide (Al ２ O ３ ), silicon oxide (SiO2), magnesium oxide (MgO), zinc oxide (ZnO), chromium oxide (Cr ２ O ３ , Cr ３ O ４ ), iron oxide (Fe ２ O ３ , Fe ３ O ４), or a composite oxide containing at least one metal element selected from cerium, zirconium, yttrium, aluminum, silicon, magnesium, zinc, chromium, and iron. The composite oxide may contain two or more metal elements selected from cerium, zirconium, yttrium, aluminum, silicon, and magnesium.

[0035] The content of the catalytic metal in the catalyst layer 35 is not particularly limited, but may be, for example, 0.01 to 50 mass % based on the mass of the carrier.

[0036] The total content of the carrier and the catalytic metal in the catalyst layer 35 may be, for example, 0.1 to 100 mass%, 1 to 100 mass%, 10 to 100 mass%, 30 to 100 mass%, 50 to 100 mass%, 70 to 100 mass%, 80 to 100 mass%, or 90 to 100 mass%, based on the mass of the catalyst layer 35.

[0037] The spiral-structured catalyst can be produced, for example, by a method including the steps of preparing a catalyst dispersion containing a particulate catalyst and a dispersion medium, immersing a spiral-structured substrate in the catalyst dispersion, removing the substrate from the catalyst dispersion, and removing the dispersion medium from the catalyst dispersion adhering to the substrate. The dispersion medium contained in the catalyst dispersion may be water, alcohol, or a combination thereof.

[0038] The present invention is not limited to the following examples.

[0039] Test 1: Methanation reaction 1-1. Structure catalyst (1) Catalyst slurry CeO ２ The powder was immersed in distilled water, and the resulting dispersion was stirred at room temperature under vacuum for 6 hours. ３ ) ３ The aqueous solution was added, and the dispersion was stirred at room temperature for 2 hours. The dispersion was heated to evaporate the water. The remaining solid was calcined by heating at 500°C for 3 hours. By calcination, Ru-supported CeO ２ Particles (Ru / CeO ２ ) powder was formed. ２ The powder was dispersed in water to form Ru / CeO ２A catalyst slurry was formed containing:

[0040] (2) Spiral-type substrate A porous metal substrate, which was a plate-shaped molded body of a nickel-chromium alloy, was prepared as the substrate. Both ends of the substrate were gripped and the substrate was twisted in a rotational direction around an axis along the longitudinal direction of the substrate. This resulted in a spiral-type substrate (diameter 11 mm, length 180 mm, L / W = 16, twist ratio = 4.09) having a porous metal portion.

[0041] (3) Formation of catalyst layer The spiral-shaped substrate was immersed in a sodium hydroxide aqueous solution. The substrate was taken out of the sodium hydroxide aqueous solution and then coated with Ru / CeO ２ The substrate was immersed in a catalyst slurry containing Ru / CeO at room temperature. The catalyst slurry attached to the substrate was taken out of the catalyst slurry and dried with hot air to form a Ru / CeO ２ A structural catalyst having a catalyst layer containing the above and covering the outer surface of the substrate was obtained.

[0042] 2-2. Methanation Reaction Test Example 1 A structure catalyst was inserted into a reaction tube (inner diameter: 12 mm) having a gas inlet and a gas outlet. Two metal conductors connected to a power source were fixed with fasteners to both ends of the structure catalyst in the reaction tube so that the tips were in contact with the metal substrate. An electric current of 5 to 10 watts was applied to the structure catalyst from the power source connected to the conductors. The temperature of the catalyst structure rose to 200°C or higher due to the application of electricity. While maintaining the application of electricity, a raw material gas was continuously introduced from the gas inlet of the reaction tube at a flow rate of 1000 mL / min. The raw material gas was a 10% by volume carbon dioxide (CO ２ ), 40% by volume of hydrogen (H ２ ), and 50% by volume of nitrogen (N ２ The CO in the product gas flowing out of the reaction tube was adjusted to contain ２ The concentration is quantified, and from the measurement results, CO ２ Conversion rate of CO to methane ２ conversion).

[0043] Comparative Example 1 As in Example 1, a structure catalyst was inserted into a reaction tube. Instead of applying electricity to the structure catalyst, the reaction tube and the structure catalyst were heated in an electric furnace set at 250°C. While maintaining the heating, as in Example 1, a raw material gas was introduced from the gas inlet of the reaction tube, and the CO in the product gas was measured. ２ The conversion rate from CO to methane was calculated.

[0044] Results Figure 4 shows the CO ２ This is a graph showing the relationship between the conversion rate and the power required to energize the structure catalyst or heat the electric furnace. It was confirmed that energizing the structure catalyst allows for more efficient methane production with less power than an electric furnace. Figure 5 is an image showing the results of thermographic measurements of the surface temperature of the structure catalyst during a reaction test. The temperature change is shown between 10 and 100 seconds after the start of the feed gas introduction. In the figure, the upper side corresponds to the upstream side of the reaction tube. It was confirmed that the temperature of the structure catalyst increased with the introduction of the feed gas, and that a highly uniform temperature distribution was maintained in the longitudinal direction of the structure catalyst during that time. Since the temperature distribution maintained a highly uniform distribution, it is believed that the methanation reaction proceeded efficiently throughout the entire structure catalyst in the longitudinal direction and in the direction perpendicular to the longitudinal direction.

[0045] Test 2: Steam reforming reaction of ethanol 2-1. Structure catalyst (1) Spiral-type substrate A porous metal substrate, which was a plate-shaped formed body of a nickel-chromium alloy, was prepared as the substrate. Both ends of the substrate were gripped, and the substrate was twisted in a rotational direction around an axis along the longitudinal direction of the substrate. This resulted in a spiral-type substrate (diameter 7 mm, length 80 mm, L / W = 11, twist ratio = 2.86).

[0046] (2) Formation of catalytic layer The substrate was immersed in an aqueous sodium hydroxide solution. The substrate removed from the aqueous sodium hydroxide solution was immersed in an aluminum sol solution containing zinc acetate. The substrate removed from the aluminum sol solution was heated to 500°C in an electric furnace and then to 600°C, thereby calcining the aluminum sol solution attached to the substrate. The calcined substrate was alternately immersed in a solution containing tin chloride and a solution containing palladium chloride. The substrate was then sequentially immersed in a solution containing hydrazine and a solution containing cobalt chloride. The immersed substrate was heated and dried to obtain a structural catalyst having a catalytic layer containing Co supported on alumina.

[0047] 2-2. Ethanol Steam Reforming Test Example 2 A structural catalyst was inserted into a reaction tube (inner diameter: 8 mm) having a gas inlet and a gas outlet. Two metal conductors connected to a power source were fixed with clamps to both ends of the structural catalyst in the reaction tube so that the tips were in contact with the metal substrate. To prevent condensation of ethanol and water vapor, the reaction tube was heated in an electric furnace set at 200°C. In this state, electricity was applied to the structural catalyst at 28, 37, 48, or 65 watts from the power source connected to the conductors. The temperature of the catalyst structure rose to 350°C, 400°C, 450°C, or 500°C by the application of electricity. In this state, a raw material gas (20°C, 1 atmosphere) was continuously introduced from the gas inlet of the reaction tube at a flow rate of 75 mL / min. The raw material gas was a mixture of 6.4% by volume of ethanol (CH ３ CH ２ OH), 80.3% by volume of water vapor (H ２ O), and 13.3% by volume of nitrogen (N ２ The total concentration of CO and CO2, methane concentration, and acetaldehyde concentration in the product gas flowing out from the reaction tube were quantified. From the measurement results, the ethanol conversion rate and the amount of hydrogen produced per minute were calculated. In addition, the CO and CO ２ The selectivity for conversion to toluene, methane, or acetaldehyde was also determined.

[0048] Comparative Example 2 A reaction test was carried out in the same manner as in Example 2, except that the structural catalyst was not energized and the reaction tube was heated in an electric furnace set at 350°C, 400°C, 450°C or 500°C.

[0049] 6 is a graph showing the relationship between the ethanol conversion rate or the amount of hydrogen produced and the temperature of the structure catalyst in Example 2. ２ 8 is a graph showing the relationship between the selectivity of conversion to CO, methane, or acetaldehyde and the temperature of the structure catalyst. FIG. 9 is a graph showing the relationship between the conversion rate of ethanol or the amount of hydrogen produced and the temperature of the electric furnace in Comparative Example 2. FIG. 10 is a graph showing the relationship between the selectivity of conversion to CO, methane, or acetaldehyde and the temperature of the structure catalyst in Comparative Example 2. ２ 1 is a graph showing the relationship between the selectivity of conversion to methane or acetaldehyde and the temperature of the electric furnace. In the case of Comparative Example 2, in which heating was performed only by the electric furnace, a decrease in conversion rate was observed when the temperature of the electric furnace was 350°C or 400°C. On the other hand, in the case of Example 2, in which heating by electrical current was used, 100% conversion rate was maintained up to 350°C, and a relatively large amount of hydrogen was also maintained. In addition, almost no acetaldehyde by-production was observed. These results can be said to be due to the synergistic effect of the combination of the structural catalyst and electrical heating.

[0050] 1... reaction tube, 3... structural catalyst, 7... power supply, 8... conducting wire, 10... reaction device, 30... substrate (plate-shaped part), 35... catalyst layer, G ０ ...raw material gas, L...length of structural catalyst, W...width of structural catalyst, S...outer surface, X...axis.

Claims

1. A method for producing a compound by a gas-solid catalytic reaction, comprising: generating a target compound from a raw material gas by a gas-solid catalytic reaction in a reaction tube containing a structure catalyst; the structure catalyst has a conductive base material extending along a certain axis and a catalyst layer provided on the base material; the base material has a plate-like portion extending along the axis while twisting in a direction rotating around the axis; the structure catalyst is inserted into the reaction tube with the axis oriented in parallel to the longitudinal direction of the reaction tube; and the raw material gas is introduced into the reaction tube while current is being applied to the base material.

2. The method according to claim 1, wherein the substrate is energized along the longitudinal direction of the reaction tube by a conductor connected to both ends of the structural catalyst and electrically connected to a power source.

3. The method according to claim 1, wherein one tube of the structured catalyst is accommodated in one of the reaction tubes.

4. The method according to claim 1, wherein a plurality of the structure catalysts are accommodated in one reaction tube, and the amount of current passing through the substrates of the plurality of the structure catalysts is controlled collectively while the raw material gas is being introduced into the reaction tube.

5. The method according to any one of claims 1 to 4, wherein the length of the structural catalyst is L and the maximum width of the structural catalyst in a direction perpendicular to the axis is W, and the ratio L / W is 2 or more and 100 or less.

6. A reaction apparatus comprising: a reaction tube; a structure catalyst accommodated in the reaction tube; a power source; and a conductor electrically connected to the power source, wherein the structure catalyst has a conductive base material extending along a certain axis and a catalyst layer provided on the base material, the base material has a plate-like portion extending along the axis while twisting in a direction rotating around the axis, the structure catalyst is inserted into the reaction tube with the axis oriented in parallel to the longitudinal direction of the reaction tube, and the conductor is connected to both ends of the structure catalyst so as to allow electricity to be applied to the base material.

7. The reaction apparatus according to claim 6, wherein one tube of the structured catalyst is accommodated in one of the reaction tubes.

8. The reaction apparatus according to claim 6, wherein a plurality of the structure catalysts are accommodated in one reaction tube, and the reaction apparatus further comprises a control unit configured to collectively control the amount of electricity applied to the substrates in the plurality of the structure catalysts.

9. A reaction apparatus according to any one of claims 6 to 8, wherein when the length of the structure catalyst is L and the maximum width of the structure catalyst in a direction perpendicular to the axis is W, the ratio L / W is 2 or more and 100 or less.

Images