Design and arrangement method of structured catalyst for hydrocarbon decomposition, manufacturing method of hydrocarbon decomposition reaction device, hydrocarbon decomposition reaction device and reactor

Abstract

The problem to be solved by the present invention is to provide a method for designing and arranging a hydrocarbon decomposition structural catalyst, a hydrocarbon decomposition reaction apparatus and a reactor and a method for manufacturing the same, which achieves high thermal utilization efficiency compared to existing methods. In order to solve the above problem, a hydrocarbon decomposition reaction apparatus (61a) is provided, comprising: a hydrocarbon decomposition structural catalyst (19) having a structure that allows reactant gases to flow from one end to the other when properly arranged in a reaction chamber; and a heat source (67) arranged inside or outside the reaction chamber, capable of heating the hydrocarbon decomposition structural catalyst (19), wherein, in a cross-sectional view perpendicular to the flow direction of the reactant gases, the hydrocarbon decomposition structural catalyst (19) has a shape that surrounds a boundary wall or boundary edge separating the hydrocarbon decomposition structural catalyst (19) from the heat source (67); and a reactor (62) that assembles the reaction apparatus (61a) together with a catalyst module (61b).

Description

Technical Field

[0001] This invention relates to the design and arrangement method of structural catalysts for hydrocarbon decomposition, the manufacturing method of hydrocarbon decomposition reaction apparatus, and hydrocarbon decomposition reaction apparatus and reactor. Background Technology

[0002] Previously, four methods for transferring heat to catalysts were known: direct heating via electricity, heat conduction, convection, and heat radiation.

[0003] Among them, it is known that thermal radiation is excellent in heating catalysts that are separated by a space with poor thermal conductivity. This can also be seen from the fact that sunlight can directly hit our skin and cause a burning sensation by passing through the non-thermal space of space and the atmosphere with poor thermal conductivity (Patent Document 1).

[0004] The thermal decomposition reaction of hydrogen from natural gas or naphtha is an endothermic reaction, especially the steam reforming reaction, which is a large endothermic reaction. Therefore, the requirements for efficient heating catalysts are high. Several reactor structures have been studied and proposed (Patent Document 2 and Patent Document 3) with a focus on the efficient utilization of heat.

[0005] Steam reforming: CH4 + 2H2O → 4H2 + CO2 ΔH = -165 kJ / mol-H2

[0006] Direct decomposition: CH4 → 2H2 + C ΔH = -76 kJ / mol - H2

[0007] When the steam reforming catalyst is a granular catalyst, it is typically filled in a space separated by a partition wall to allow the flow of feed gas. Heat from the burner is transferred to this partition wall, and then from the partition wall to one granular catalyst via convective heat transfer from the feed gas. Other granular catalysts in the filling are heated by heat radiation from this granular catalyst or by convective heat transfer from the feed gas (Non-Patent Document 1). In such a catalyst bed reactor system, the heat transfer within the catalyst bed is mainly via fluid convection, resulting in poor thermal efficiency. The feed gas (hydrocarbons and steam) needs to be preheated to around 500°C (e.g., Patent Documents 5, 6, etc.). Furthermore, the pressure loss within the catalyst bed is also significant, leading to slow responsiveness to load changes or startup, slow temperature rise in the reaction field, and slow temperature tracking. Additionally, to heat the catalyst within the reaction tube, the reaction tube must be lengthened, easily resulting in a larger-scale unit.

[0008] Prior art literature

[0009] Patent documents

[0010] Patent Document 1: Japanese Patent Application Publication No. 6-229530

[0011] Patent Document 2: Japanese Patent Application Publication No. 2001-031403

[0012] Patent Document 3: Japanese Patent Application Publication No. 2000-178004

[0013] Patent Document 4: International Publication No. 2020 / 090245, Figure 7 b

[0014] Patent Document 5: Japanese Patent Application Publication No. 2004-83332

[0015] Patent Document 6: Japanese Patent Publication No. 2019-529318

[0016] Non-patent literature

[0017] Non-Patent Literature 1: Fukuhara, “Development of Metal Honeycomb Structure Catalysts for Hydrocarbon Reforming and Application to Next-Generation Compact Hydrogen Generators”, ENEOS Technical Review, Vol. 53, No. 3, pp. 94-100 Summary of the Invention

[0018] The problem that the invention aims to solve

[0019] When heating the plate-shaped catalyst used for steam reforming, there is a method that first heats the reaction gas using a heater arranged around the perimeter of the reactor or along the vertical centerline, and then heats the entire catalyst 59 by the high-temperature reaction gas (Patent Document 2, Patent Document 4). Figure 10 One approach involves arranging the catalyst structure in direct contact with the heater partition wall, using direct heat conduction to heat the catalyst (Non-Patent Document 1). However, given that the catalytic reaction occurs only near the boundary film on the surface of the catalyst structure, and considering that heated reactant gases outside the boundary film contribute nothing to the reaction, the former method suffers from significant energy loss, and a more efficient heating method is desired. The latter method faces compatibility issues between the heater partition wall and the catalyst components, the need to replace the entire heater partition wall due to catalyst degradation, limitations on catalyst area, and other factors, presenting significant obstacles from a practical standpoint.

[0020] In view of the above situation, the object of the present invention is to provide a method for designing and arranging a structural catalyst for hydrocarbon decomposition with high thermal efficiency compared to existing methods, a hydrocarbon decomposition reaction apparatus and reactor and a method for manufacturing the same.

[0021] Technical means to solve the problem

[0022] One aspect of the present invention, made to achieve the above-mentioned objectives, is a hydrocarbon decomposition reaction apparatus, comprising: a hydrocarbon decomposition structural catalyst having a structure that allows reactant gases to flow from one end to the other when properly arranged in a reaction chamber; and a heat source arranged inside or outside the reaction chamber, capable of heating the hydrocarbon decomposition structural catalyst. In a cross-sectional view perpendicular to the flow direction of the reactant gases, the hydrocarbon decomposition structural catalyst has a shape surrounding a boundary wall or boundary edge that separates the hydrocarbon decomposition structural catalyst from the heat source. According to this configuration, a structure is formed that can receive radiant heat released along the normal direction without omission on the same catalyst surface or adjacent catalyst surfaces, and can also receive a portion of the radiant heat released beyond the normal direction. Only the reactant gases near the boundary membrane are heated by the catalyst plates heated by radiant heat, enabling highly efficient heat utilization.

[0023] In the aforementioned hydrocarbon decomposition reactor, the preferred shape is a shape that is symmetrical about the normal to the boundary wall or the normal to the side of an imaginary cylinder containing the boundary edge. This configuration results in a high probability that any radiant heat absorbed and released by the catalyst surface, or reflected radiant heat, is received by the same catalyst surface or other catalyst surfaces symmetrical about the normal, thus enabling more efficient utilization of radiant heat.

[0024] In the aforementioned hydrocarbon decomposition reaction apparatus, the heat source is preferably housed inside the reaction chamber within a heater housing that occupies a substantially central position in a cross-sectional view perpendicular to the flow direction of the reaction gas. This configuration is advantageous when utilizing radiant heat, as it results in a smaller surface area to be heated and separation from the low-temperature external gas compared to heating the outer edge of the reaction chamber.

[0025] In the aforementioned hydrocarbon decomposition reactor, the heat source is preferably a regenerative radiant tube burner, housed within a square heater housing that occupies approximately the central position in a cross-sectional view perpendicular to the flow direction of the reactant gases. This configuration allows the high thermal efficiency of the regenerative radiant tube burner to be utilized, while simultaneously enabling effective heating only of the catalyst surface that contributes to the reaction.

[0026] Another aspect of the present invention is a reactor for direct hydrocarbon decomposition, comprising the aforementioned hydrocarbon decomposition reaction apparatus. With this configuration, the steam heater, feed gas preheater, CO conversion unit, and CCS unit necessary for steam reforming are not required, allowing for overwhelming miniaturization compared to existing hydrogen generation units. Furthermore, it is also considered advantageous in terms of heat balance, as the preheating or pressurization of feed gases is not required.

[0027] The reactor for direct hydrocarbon decomposition preferably also includes a second structural catalyst that can contact unreacted reactant gases discharged from the other end via convection. By combining a so-called permeable structural catalyst in which reactant gases flow from one end to the other with a second structural catalyst that can contact the reactant gases via convection, a constant production rate can be maintained while reducing the proportion of unreacted reactant gases, thereby improving the conversion rate.

[0028] The reactor for direct hydrocarbon decomposition also includes a hydrogen refining module, which is used to reduce the hydrogen partial pressure inside the reactor by selectively removing hydrogen, thereby promoting the hydrocarbon decomposition reaction. Based on this configuration, by reducing the hydrogen concentration inside the furnace, the direct hydrocarbon decomposition reaction can be promoted on the hydrogen generation side.

[0029] Another aspect of the present invention is a method for designing and arranging a structural catalyst for hydrocarbon decomposition, comprising: determining the shape of a reaction chamber and the shape and arrangement of a heat source inside or outside the reaction chamber; arranging a structural catalyst for hydrocarbon decomposition of a first shape at a first position in a first coordinate system; calculating or measuring the radiant heat (E1) received by the structural catalyst for hydrocarbon decomposition of the first shape per unit time; deforming and / or moving the coordinate system of the structural catalyst for hydrocarbon decomposition of the first shape; confirming that when the deformed and / or moved structural catalyst for hydrocarbon decomposition is arranged in the reaction chamber, the reaction gas can flow from one end to the other; confirming that the radiant heat (E2) received by the deformed and / or moved structural catalyst for hydrocarbon decomposition in the reaction chamber is greater than the radiant heat (E1) received by the structural catalyst for hydrocarbon decomposition of the first shape per unit time. According to this design and arrangement method, even with the same catalyst area, it is possible to design and arrange a catalyst that is heated at high temperatures primarily by radiant heat, mainly on the catalyst surface, and to achieve efficient heat utilization even without considering other heating factors such as heat conduction and convection of the reaction gas. Furthermore, by using positive values ​​for E2-E1 as a condition, and by repeatedly deforming the shape of the hydrocarbon decomposition structure catalyst and confirming the radiative heat value, the shape and arrangement of the hydrocarbon decomposition structure catalyst can be optimized.

[0030] Another aspect of the present invention is a method for manufacturing a hydrocarbon decomposition reaction apparatus, which includes the above-described method for designing and arranging a structural catalyst for hydrocarbon decomposition. According to this manufacturing method, even with the same catalyst area, it is possible to design and arrange a catalyst that can be heated at high temperatures primarily on the catalyst surface through radiant heat, achieving efficient heat utilization even without considering other heating factors such as heat conduction and convection of the reactant gases.

[0031] The effects of the invention

[0032] According to the present invention, by directly applying heat to the catalyst surface and raising the temperature only near the boundary film of the catalyst where the actual chemical reaction occurs to the reaction temperature, the heating efficiency of the structural catalyst for hydrocarbon decomposition can be improved, the reactor temperature can be reduced, and in some cases, inexpensive structural materials with low heat resistance can be used as reactor feedstock. Attached Figure Description

[0033] Figure 1 This is a BB cross-sectional view of the first embodiment of the hydrocarbon decomposition reaction apparatus of the present invention.

[0034] Figure 2 yes Figure 1 An enlarged cross-sectional view of section AA inside the lower open cylinder.

[0035] Figure 3 (a) is a side view of the second embodiment with the catalyst arranged. Figure 3 (b) is an AA end view of the second embodiment with the catalyst arranged.

[0036] Figure 4 This is a cross-sectional view of the catalyst arrangement in the third embodiment, viewed from a section perpendicular to the flow direction of the reactant gas.

[0037] Figure 5 (a) is a CC end view of the fourth embodiment with the catalyst arranged thereon. Figure 5 (b) is a cross-sectional view (AA) of the fourth embodiment with the catalyst arranged therein. Figure 5 (c) is a cross-sectional view of the fourth embodiment with the catalyst BB arranged.

[0038] Figure 6 This is a schematic diagram of the reactor in the fifth embodiment.

[0039] Figure 7 This is a cross-sectional view showing the arrangement of the modified catalyst plates of Experimental Example 1.

[0040] Figure 8 This is the result curve of Experiment Example 1.

[0041] Figure 9 This is the result curve of Experiment Example 3.

[0042] Figure 10 This is a cross-sectional view showing a conventional example of catalyst composition. Detailed Implementation

[0043] The following defines the terms used in this specification.

[0044] In this specification, "structured catalyst for hydrocarbon decomposition" refers to a structured catalyst used in all or part of the steam reforming reaction of hydrocarbons, or in all or part of the direct decomposition reaction of hydrocarbons. The hydrocarbons are preferably methane, ethane, propane, or naphtha.

[0045] In this specification, "structured catalyst" refers to a catalyst selected from a structure that functions as a catalyst, either a plate (including not only flat plates but also plates that have undergone any processing, such as bending, folding, punching, cutting, embossing, etc.), a porous body, a honeycomb structure (monolithic type), a felt, a mesh, a fabric, or an expanded metal structure, or a catalyst based on such a structure. As a structure-based catalyst, it generally refers to a catalyst obtained by impregnating a substrate with a honeycomb or similar shape into a slurry containing catalyst components. However, it can also be a catalyst in which an exposed, unsupported catalyst layer (coating, thermal spray coating) is formed on the structure through thermal spraying, plating, or other methods.

[0046] In this specification, "flow direction of the reactant gas" refers to the straight or curved flow direction of the reactant gas in the reaction chamber as observed from a distance. Therefore, to promote stirring contact, it should be noted that even when the flow of the reactant gas is modified by adding protrusions to the catalyst or by placing baffles in the flow path, causing localized, microscopic changes in the flow path, these localized, microscopic changes may not necessarily be consistent with the direction of the reactant gas flow when observed from a distance.

[0047] In this specification, "boundary wall" refers to the macroscopic geometric boundary wall used to define the linear thermal radiator and / or normal vector. Therefore, the fine surface conditions of the wall are not considered. Additionally, "boundary wall" can be the surface of the heat source itself, or the wall of a cylindrical partition or a hollow partition with a rectangular cross-section that separates the heat source from the space within the reaction chamber.

[0048] In this specification, "boundary edge" refers to each side of the heat source or partition wall when viewed from a cross-section perpendicular to the flow direction of the reacting gas, in the case where the heat source or partition wall is rectangular or square.

[0049] In this specification, "imaginary cylinder side surface" refers to the side surface of the imaginary cylinder when considering an imaginary cylinder including its boundary edges.

[0050] In this specification, "normal relative to the boundary wall or normal relative to the side of the imaginary cylinder containing the boundary edge" does not refer to all normals, but to a specific normal selected.

[0051] Hereinafter, embodiments of the present invention will be described with appropriate reference to the accompanying drawings.

[0052] (First embodiment - an apparatus in which the catalyst is arranged symmetrically with respect to the normal)

[0053] Figure 1 The typical hydrocarbon decomposition reaction apparatus 1 shown has a structure in which a lower-end open cylinder 4, into which a region 3 for which a hydrocarbon decomposition reaction is defined is inserted in a product discharge container 2, and further includes: a supply pipe 6 that supplies reaction gas to the upper part of the lower-end open cylinder 4 through a cover 5 located at the upper end of the lower-end open cylinder 4; a discharge pipe 8 that discharges gas containing the reaction gas through a cover 7 located at the upper end of the product discharge container 2; a hydrocarbon decomposition structure catalyst 9 having a structure that allows reaction gas to flow from the upper end to the lower end when arranged in the lower-end open cylinder 4; a bottomed cylinder 11 that extends downward in a vertical direction through approximately the center of the upper cover 5 of the lower-end open cylinder 4; and a heat source 10 housed in the bottomed cylinder 11.

[0054] like Figure 2 As shown, in a cross-sectional view perpendicular to the vertical direction of the reactant gas flow, the hydrocarbon decomposition structure catalyst 9 in this embodiment has a chrysanthemum-like outline, surrounding the outer wall (boundary wall) of the bottom cylinder 11. The chrysanthemum is formed by combining two curved catalyst pieces facing each other, resulting in 23 petals arranged in an integrated manner from the inner ends towards the center of adjacent petals. The leading end point 14 of the petals is located on the normal 13 relative to the boundary wall 12, forming a symmetrical curve with respect to the normal 13. Viewed from the side, one side of the two curved catalyst pieces meets at the portion corresponding to the leading end of the petal.

[0055] (Second embodiment - a device in which the catalyst is arranged symmetrically with respect to the normal)

[0056] Figure 3 The difference between the second embodiment shown in (a) and the first embodiment is that, in a cross-sectional view perpendicular to the vertical direction of the reaction gas flow, as shown in (a)... Figure 3 As shown in (b), the cylindrical hydrocarbon decomposition structure catalyst 19 surrounding the bottom cylinder 11 is corrugated (rippled). In this arrangement, in a cross-sectional view perpendicular to the vertical direction of the reaction gas flow, the catalyst 19 is formed into a curve or straight line shape that originates from a point 16 on the normal 15 relative to the boundary wall 12 and is symmetrical with respect to the normal 15.

[0057] (Third embodiment - a device in which the catalyst is arranged asymmetrically with respect to the normal)

[0058] Figure 4The third embodiment shown differs from the first embodiment in that, in a cross-sectional view perpendicular to the direction of the reactant gas flow, 15 L-shaped catalyst plates 29 are arranged around the bottom cylinder 11 without gaps between adjacent catalyst plates 29a and 29b, thereby surrounding the boundary wall 12. In this arrangement, the catalyst 29 "inclines" across the normals 17a and 17b relative to the boundary wall 12, forming a shape that is asymmetrical with respect to a point 18a or 18b on the normals 17a and 17b relative to the boundary wall 12.

[0059] (Fourth embodiment - A device having a catalyst around a regenerative radiant tube burner)

[0060] exist Figure 5 In the fourth embodiment shown, the heat source 20 is a regenerative radiant tube burner 27, comprising: a radiant tube 22 that is approximately W-shaped when viewed from the side; a pair of gas burners 24 disposed at both ends of the radiant tube 22; and a pair of regenerators 26 disposed at both ends of the radiant tube 22. The entire tube 22 of the burner 27 is housed within a rectangular heater housing 25. The flow direction of the reaction gas is towards... Figure 5 (a) The direction of the inside of the paper, Figure 5 (b) and Figure 5 (c) In a cross-sectional view perpendicular to the flow direction of the reactant gas, from top to bottom, U-shaped and horseshoe-shaped hydrocarbon decomposition catalyst structures 39 are arranged in close contact around the four side walls and four sides of the heater housing 25, respectively, such that no gaps are formed between adjacent catalyst plates 39a, 39b, and 39c with their openings facing the same direction. In this arrangement, the shapes of the catalysts 39a, 39b, and 39c include: Figure 5 (a) shows a cross-sectional view of the reaction gas flow in the vertical direction, with a point 38a on the normal 37a relative to the boundary wall 32 as the starting point and a shape symmetrical with respect to the normal 37a, and a shape asymmetrical with respect to the normal 37b on the normal 37b of the imaginary cylindrical side 34 containing the boundary edge 33 on the inner side.

[0061] (Fifth embodiment - Reactor housing multiple standardized catalyst modules)

[0062] Figure 6 The reactor 62 shown in the fifth embodiment has a hydrocarbon decomposition reaction apparatus 61a, a catalyst module 61b, and a crude purification apparatus 65, which are standardized catalyst modules.

[0063] The hydrocarbon decomposition reaction apparatus 61a includes: a single-ended radiant tube burner 67 as a heat source, and components arranged around the burner 67. Figure 3 The device 61a includes a waveform catalyst 19 (first structural catalyst) and a guide tube 64a that can introduce reactant gas when the upper end of the waveform catalyst 19 is contained. Since the feed gas passes through the inside of the waveform catalyst 19 from top to bottom, this device 61a is a gas-permeable catalyst, but... Figure 1 Unlike the lower-opening cylinder 4, the guide tube 64a forms a sleeve that only covers the upper part of the catalyst. The raw material gas escaping from the lower end of the wave-shaped catalyst 19 also comes into contact with the outside of the wave-shaped catalyst 19, thereby diffusing throughout the entire reactor 62.

[0064] The catalyst module 61b differs from the hydrocarbon decomposition reactor 61a in that it includes a second structural catalyst 69 capable of contacting unreacted reaction gases discharged from the lower end of the hydrocarbon decomposition reactor 61a via convection, and a retaining cylinder 64b holding the second structural catalyst 69 from above. The second structural catalyst 69 does not surround the burner 67.

[0065] As the second structural catalyst 69, the same or different materials as the first structural catalyst 19 can be used. Since there may be no heat source in the center surrounded by the structure, the second structural catalyst can be selected from plates (including not only flat plates, but also plates that have undergone arbitrary processing, such as bending, folding, punching, cutting, embossing, etc.), porous bodies, honeycomb bodies (integral type), felt, mesh, fabric, or expanded metal, among other structures that are different from the structure of the first structural catalyst 19.

[0066] As a heating method for the second structural catalyst 69, it can be positioned facing the gas-permeable catalyst to utilize the radiant heat generated by the gas-permeable catalyst, or the catalyst surface can be heated by the convection of high-temperature gas inside the furnace.

[0067] A reaction gas supply pipe 66a is connected to the upper end face of the reactor 62 to supply the reaction gas to the aforementioned hydrocarbon decomposition reactor 61a. In addition, the hydrocarbon decomposition reactor 61a is provided with a combustion gas inlet pipe 66b for supplying combustion gas to the burner 67 and a blower 68 for supplying air.

[0068] A desulfurizer 63 is installed between the raw gas supply pipe 66a and the raw gas supply source 71. By installing the desulfurizer 63, sulfur compounds added to city gas or LPG as odorants can be removed, preventing poisoning or performance degradation of the catalyst.

[0069] A discharge and recovery device 72 for the carbon generated in the hydrocarbon decomposition reaction apparatus 61a and catalyst module 61b is connected to the lower end face of the reactor 62.

[0070] A typical discharge recovery device, as shown in Patent Document 4, includes: a pressure-reducing chamber connected to the lower opening of the reactor via a ventilation hole; a first switching valve capable of opening and closing the ventilation hole; a recovery tank connected to the pressure-reducing chamber via a channel; a second switching valve capable of opening and closing the channel; and a pressure-reducing pump connected to the recovery tank.

[0071] The crude purification device 65 is a device that reduces the hydrogen concentration inside the reactor 62 and makes the hydrogen concentration discharged outside the reactor 62 higher than the concentration inside the reactor. As for its materials, examples include those described in Japanese Patent Application Publication No. 2020-142160 and Japanese Patent Application Publication No. 2006-007134, which contain or support porous substrates made of ceramic materials such as α-alumina, γ-alumina, silica, zirconium oxide, silicon nitride, silicon carbide, titanium dioxide, and zeolite, or metallic materials such as nickel, copper, iron, zinc, and their alloys, and have controlled pores, such as silica films, palladium (Pd) films, palladium alloy (PdAg, PdCu, etc.) films, vanadium films, zirconium / nickel alloy films, and zeolite films.

[0072] The high-hydrogen-concentration generated gas from the crude purification unit 65 is temporarily stored in tank 74 using pump 73. After fine purification by pressure swing adsorption (PSA) 75, it becomes product hydrogen. Commercially available PSAs can be used.

[0073] The methane separated by PSA75 can be combined with the reaction gas inlet pipe 66 via a reflux pipe (not shown) for reuse as a reaction gas.

[0074] (Design and arrangement methods of structural catalysts for hydrocarbon decomposition)

[0075] The design and arrangement method of a structural catalyst for hydrocarbon decomposition (hereinafter referred to as "this method") is another aspect of the present invention. The steps are described below.

[0076] This method includes the step of determining the shape of the reaction chamber and the shape and arrangement of the heat source inside or outside the reaction chamber (S1). The shape of the reaction chamber can be a typical shape of a tubular reactor, a fixed-layer reactor, or a packed-layer catalyst reactor. The shape and arrangement of the heat source is, for example, a bottomed cylindrical shape arranged inside the reaction chamber in a manner that occupies a substantially central position in a cross-sectional view perpendicular to the flow direction of the reactant gases.

[0077] This method includes the step (S2) of arranging a hydrocarbon decomposition catalyst of a first shape at a first position in a first coordinate system. In the initial setup of this step, such as... Figure 10 As shown, the first shape is set as a plate-shaped catalyst. In a cross-sectional view perpendicular to the flow direction of the reactant gas, the first position of the first coordinate system can be radial, that is, it can be set on a plane containing the normal to the boundary wall separating the heat source from the reaction chamber. Alternatively, the first shape can also be set as a cylindrical shape with openings at both ends.

[0078] This method includes a step (S3) of calculating or measuring the radiant heat (E1) received per unit time by a hydrocarbon decomposition catalyst of the first shape. In this step, when calculating radiant heat, the emissivity of the object can be determined based on known data, and the radiant heat can be simulated and calculated according to the Stefan-Boltzmann law. In actual measurement, the radiant heat can also be calculated by observing the temperature distribution and temperature rise rate at various points on the catalyst surface using a thermal imager, thermocouples, etc. In addition, in the case of actual measurement, in order to disregard other heating factors such as heat conduction and convection of the reactant gas, it is preferable to perform radiant heating with a vacuum in the reaction chamber. However, to approximate the actual conditions, radiant heating can also be performed with the reactant gas filled or circulating.

[0079] This method includes the steps of deforming the hydrocarbon decomposition catalyst of the first shape and / or moving the coordinate system (S4). In actual measurements, this deformation is performed, and the coordinate system is moved, for example, by changing the position or tilt angle on the frame. The changes in position and tilt angle are achieved, for example, by setting large-diameter rings and small-diameter rings at the upper and lower ends of the frame, and arranging bridges connecting the large-diameter rings and small-diameter rings radially. Teeth are formed at intervals on each bridge, with the upper and lower bridges facing each other, and the position between the teeth at the upper and lower ends of the catalyst is changed independently. In calculations, this is achieved by deforming and moving the coordinate system on a computer.

[0080] This method includes a step (S5) to confirm that the reactant gas can flow from one end to the other when a modified and / or repositioned hydrocarbon decomposition catalyst structure is arranged in the reaction chamber. Flow confirmation can be performed, for example, by setting a hypothetical reactant gas inlet and a hypothetical catalyst at a predetermined location in a hypothetical reaction chamber on a computer, simulating whether the fluid moves from one end of the catalyst to the other; or by setting a reactant gas inlet at a predetermined location in an actual reaction chamber, confirming whether the reactant gas flows from one end of the catalyst to the other. It should be noted that, during simulation, to ensure that the reactant gas can flow from one end to the other, the reactant gas inlet in the reaction chamber can also be moved when the coordinate system of the hydrocarbon decomposition catalyst structure is moved, provided the design allows.

[0081] This method includes a step (S6) to confirm that the radiant heat (E2) received per unit time by the deformed and / or coordinate-shifted hydrocarbon decomposition structure catalyst within the reaction chamber is greater than the radiant heat (E1) received per unit time by the hydrocarbon decomposition structure catalyst of the first shape. Confirmation of whether the radiant heat has increased is performed as follows: in the case of actual measurement, by comparing the temperature distribution and temperature rise rate at the same location on the catalyst surface where E1 is measured using a thermal imager, thermocouple, etc.; in the case of calculation, by determining the emissivity of the object based on known data and performing simulation calculations according to the Stefan-Boltzmann law.

[0082] The following is a detailed description of embodiments of the apparatus using the catalyst with the above-described structure.

[0083] (Experimental Example 1 - Reaction Experiment Based on Internally Heated Reactor Using Modified Catalyst Plates)

[0084] A heater housing 11, housing a 2kW heater (manufactured by Sanyo Thermal Industries, Ltd.), is inserted along the vertical central axis of a cylindrical SUS304 permeable small reactor. In a cross-sectional view perpendicular to the methane flow direction, 46 catalyst plates 49 (nickel-based metal catalysts), each 0.6mm thick, 37mm wide, and 200mm long, are arranged as shown. Figure 7 As shown, the catalysts are arranged and fixed around the heater housing 11 in a manner with the same orientation and curvature, and protrusions 46 are provided on the catalyst plate 49 to promote stirring contact. The total geometric area of ​​the catalyst is 0.68 m² on both sides. 2 .

[0085] After the reactor temperature rises to around 600°C, methane is introduced from the methane supply pipe of the furnace cover in a manner parallel to the catalyst. The methane flow is then introduced at a pressure of 0.3 MPa and a flow rate of 1000 mL / min. The direct decomposition reaction of methane is carried out at a heater temperature of 950–1000°C for about 2 hours and 25 minutes.

[0086] The hydrogen concentration was measured using a gas thermal conductivity analyzer (zero-point gas: city gas 13A, range gas: hydrogen 100%, gas flow rate: 1.0 L / min, manufactured by Chino Co., Ltd.) installed on the exhaust pipe 8 of the generated gas released into the atmosphere at the lower end of the furnace peripheral wall. The results are shown in... Figure 8 However, the heater temperature is close to 950°C, but the reactor temperature is as low as 650°C. Therefore, the boundary film portion of the catalyst plate 49 is not sufficiently heated, resulting in low hydrogen production efficiency.

[0087] Even if the heater temperature is increased from 950°C to 1000°C midway through the experiment, the hydrogen production efficiency of the catalyst is at most 10%, so the experiment was stopped.

[0088] (Experimental Example 2 - Radiation Heating Experiment with Catalysts Arranged in a Chrysanthemum-Shaped Cross-Sectional View)

[0089] Two catalyst plates of the same size as in Experimental Example 1 were grouped together and bent relative to each other. 23 groups were arranged around the heater housing, and the opposite edges of adjacent plates were butt-welded together. This resulted in a chrysanthemum-shaped profile in a cross-sectional view perpendicular to the methane flow direction. Figure 2 ).

[0090] With the heater driven in an open atmosphere, the catalyst is observed through thermal imaging. It is evident that the heat from the heater diffuses uniformly across the entire surface receiving thermal radiation (radiative heat) from near the root fork of the petals to near the tip. In a cross-sectional view perpendicular to the flow direction of the reactant gas, the hydrocarbon decomposition catalyst structure exhibits a shape that is bilaterally symmetrical, originating from a point on the normal to the boundary wall. This shape allows thermal radiation reflected from one catalyst plate surface to be easily received by the other. Conversely, the side of the catalyst plate opposite to the surface receiving thermal radiation is at a low temperature, indicating localized heating of the catalyst plate surface.

[0091] (Experimental Example 3 - Using, for example) Figure 2 (Reaction experiment with an internally heated reactor containing a catalyst)

[0092] The total geometric area arranged as in Experiment 2 is 0.68m² on both sides. 2 The catalyst and heater were housed along the vertical central axis of a cylindrical, permeable miniature reactor. Methane was introduced through a methane flow path at a methane supply pressure of 0.3 MPa and a methane flow rate of 1 L / min to conduct a direct methane decomposition reaction experiment. The results are as follows: Figure 9 As shown, compared to the internally heated reactor of Experimental Example 1, although the total geometric area of ​​the catalyst and the heater capacity are the same, the hydrogen production is good, with a heater temperature of 1000°C, a reactor temperature of 650°C, and a hydrogen concentration of 55%. This suggests the importance of designing the catalyst arrangement to facilitate localized heating of the catalyst plate surface by radiant heat.

[0093] It should be noted that the embodiments of the present invention are not limited to the above-described embodiments, and all the configurations described in the above embodiments are not necessarily necessary conditions for the present invention. The present invention can be modified in various ways without departing from its technical concept, as long as it falls within the scope of this technology. For example, in the fourth embodiment, the heater housing 25 is not necessary, and omitting it improves thermal efficiency. As in the case of directly arranging regenerative radiant tubes in a vacuum heat treatment furnace, the heater housing 25 is unnecessary as long as the burner's airtightness is sufficiently high. Furthermore, although only the upper part of the second structure catalyst 69 is housed in the retaining cylinder 64b, it can also be exposed in the reactor 62.

[0094] Industrial availability

[0095] The hydrocarbon decomposition reaction apparatus of the present invention, by installing a device in the latter stage to improve the purity of hydrogen contained in the generated gas, is applicable to supplying hydrogen to fuel cell vehicles equipped with solid polymer fuel cells (PEFCs) via field stations.

[0096] In addition, in recent years, solid oxide fuel cells (SOFCs), which can directly utilize methane by leveraging city gas infrastructure, have attracted attention, in addition to hydrogen. In SOFCs, it has been previously recognized that the performance is reduced due to the deposition of carbon onto the surface of metallic nickel caused by the thermal decomposition reaction of methane, and the electrode reaction inhibition caused by the adsorption of generated CO onto the surface of metallic nickel (Sato et al., “From the perspective of fuel cell methane utilization technology”, J. Plasma Fusion Res. Vol. 87, No. 1 (2011) 36-41). If the hydrocarbon decomposition reaction device of the present invention is used as a fuel reformer arranged in front of it, it is expected to reduce the carbon deposition in SOFCs or extend their lifespan.

[0097] Symbol Explanation

[0098] 1. 61a Hydrocarbon decomposition reaction apparatus

[0099] 61b Catalyst Module

[0100] 62 Reactor

[0101] 2. Product discharge container

[0102] 3 areas

[0103] 4. Open-end cylindrical tube

[0104] 5, 7 covers

[0105] 6.66a Reactor Gas Supply Pipe

[0106] 8. Discharge pipe

[0107] 9, 19, 29, 39a, 39b, 39c, 49, 59, 69 Hydrocarbon decomposition catalysts

[0108] 10, 20 heat sources

[0109] 11. With a bottom cylinder (heater storage section)

[0110] 12 Boundary walls

[0111] Normals 13, 15, 17a, 17b, 37a, 37b

[0112] Points where catalysts 14, 16, 18a, 18b, 38a, and 38b intersect the normal.

[0113] 22 Radiant Tubes

[0114] 24 Gas burner

[0115] 25. Heater storage section

[0116] 26. Heat accumulator

[0117] 27 and 67 burners

[0118] 33 Boundary edge

[0119] 34. Imaginary cylindrical side

[0120] 46. ​​Protrusion

[0121] 63 Desulfurizer

[0122] 64a Guide tube

[0123] 64b retainer

[0124] 65. Crude purification device

[0125] 66b Combustion gas inlet pipe

[0126] 68 Blower

[0127] 71 Raw material gas supply source

[0128] 72. Carbon emission recovery device

[0129] 73 pumps

[0130] 74 cans

[0131] 75 PSA

Claims

1. A hydrocarbon decomposition reaction apparatus, comprising: A structural catalyst for hydrocarbon decomposition, having a structure that allows the feed gas to flow from one end to the other when properly arranged in the reaction chamber; as well as A heat source, arranged inside the reaction chamber in an airtight manner, is capable of heating the hydrocarbon decomposition structure catalyst; In a cross-sectional view perpendicular to the flow direction of the feed gas, the hydrocarbon decomposition structure catalyst has a shape that seamlessly surrounds the boundary wall or boundary edge that separates the hydrocarbon decomposition structure catalyst from the heat source.

2. A hydrocarbon decomposition reaction apparatus, comprising: A structural catalyst for hydrocarbon decomposition, having a structure that allows the feed gas to flow from one end to the other when properly arranged in the reaction chamber; as well as A heat source, arranged inside the reaction chamber in an airtight manner, is capable of heating the hydrocarbon decomposition structure catalyst; In a cross-sectional view perpendicular to the flow direction of the feed gas, the hydrocarbon decomposition structure catalyst has a shape that is symmetrical with respect to a point on the normal to the boundary wall separating the hydrocarbon decomposition structure catalyst from the heat source or on the normal to the imaginary cylindrical side surface containing the boundary edge.

3. The hydrocarbon decomposition reaction apparatus according to claim 1, wherein, The shape is a shape that starts from a point relative to the normal of the boundary wall or the normal of the side of an imaginary cylinder containing the boundary edge, and is symmetrical with respect to that normal.

4. The hydrocarbon decomposition reaction apparatus according to claim 1 or 2, wherein, The heat source is housed inside the reaction chamber within a heater housing that occupies a generally central position in a cross-sectional view perpendicular to the flow direction of the raw material gas.

5. The hydrocarbon decomposition reaction apparatus according to claim 4, wherein, The heat source is a regenerative radiant tube burner, housed within a square heater housing that occupies approximately the central position in a cross-sectional view perpendicular to the flow direction of the raw material gas.

6. A reactor for direct decomposition of hydrocarbons, comprising the hydrocarbon decomposition reaction apparatus according to any one of claims 1 to 3.

7. The reactor for direct hydrocarbon decomposition according to claim 6, wherein, The catalyst includes a second structure, and unreacted feed gas discharged from the other end can come into contact with the second structure catalyst through convection.

8. The reactor for direct hydrocarbon decomposition according to claim 6, wherein, It also includes a hydrogen refining module, which is used to reduce the hydrogen partial pressure in the reactor by selectively removing hydrogen from the reactor, thereby promoting the decomposition reaction of hydrocarbons.

9. A method for designing and arranging a structural catalyst for hydrocarbon decomposition, comprising: The shape of the reaction chamber and the shape and arrangement of the heat source are determined, the heat source being arranged inside the reaction chamber in an airtight manner; A hydrocarbon decomposition structure catalyst of the first shape is arranged at a first position in a first coordinate system. In a cross-sectional view perpendicular to the flow direction of the feed gas, the hydrocarbon decomposition structure catalyst of the first shape surrounds without gaps the boundary wall or boundary edge that separates the hydrocarbon decomposition structure catalyst from the heat source. Calculate or measure the radiant heat E1 per unit time received by the catalyst of the first-shape hydrocarbon decomposition structure. The first-shaped hydrocarbon decomposition catalyst is deformed and / or the coordinate system is moved in a state where the boundary wall or boundary edge is surrounded without gaps. When a modified and / or coordinate-shifted hydrocarbon decomposition catalyst structure is arranged in the reaction chamber, the feed gas can flow from one end to the other. It is confirmed that the radiant heat E2 per unit time received by the deformed and / or coordinate-shifted hydrocarbon decomposition structure catalyst in the reaction chamber is greater than the radiant heat E1 per unit time received by the hydrocarbon decomposition structure catalyst of the first shape.

10. A method for manufacturing a hydrocarbon decomposition reaction apparatus, comprising the design and arrangement method of the hydrocarbon decomposition structural catalyst as described in claim 9.

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