Methane pyrolysis apparatus

Abstract

The present invention relates to a methane pyrolysis device. The methane pyrolysis device may include: a fluidized bed reaction unit that pyrolyzes methane into a carbon mixture using a catalyst; a primary cyclone unit that primarily collects carbon mixture particles discharged from the fluidized bed reaction unit; a feedback unit that recirculates the catalyst primarily collected in the primary cyclone unit to the fluidized bed reaction unit; and an overflow separation unit that separates primary carbon particles with a density lower than that of the catalyst from the carbon mixture primarily collected in the primary cyclone unit.

Description

Technology Field

[0001] The present invention relates to a methane pyrolysis device. Background Technology

[0002] Generally, blue-green hydrogen production technology is gaining attention for producing hydrogen by thermally or catalytically decomposing methane under oxidation-free conditions. Depending on process characteristics, such blue-green hydrogen production technologies can be broadly classified into plasma methods, molten metal catalyst methods, and high-temperature dry pyrolysis methods.

[0003] Among them, the plasma method is a technically mature form of methane pyrolysis technology that uses a plasma torch to pyrolyze methane at temperatures ranging from a low-temperature plasma of about 1,000°C to a high-temperature plasma of 2,000°C. This plasma method has the advantage of high decomposition efficiency and a fast reaction rate because it can supply very high energy locally through the plasma.

[0004] The molten metal catalyst method is inspired by the reduction technology of liquid metals such as tin, utilizing the principle that hydrogen and solid carbon are generated when the oxygen in the metal is completely depleted by supplying methane into high-temperature molten metal. This molten metal catalyst method has the advantage of enabling stable reaction control due to the ease of handling reaction byproducts and uniform heat transfer.

[0005] High-temperature dry pyrolysis methods are classified into detailed technologies based on the reactor type, operating temperature, and the application of catalysts. Among these, when utilizing a catalytic circulating fluidized bed reactor, the circulating flow behavior of particles within the reactor allows for the maintenance of a uniform temperature distribution with minimal temperature variation across the entire reaction area. This uniform thermal distribution suppresses the occurrence of localized hot spots, and even under conditions of high gas flow rates, the catalyst is uniformly dispersed. As the gas-to-carbon contact area expands, diffusion resistance is reduced, and reaction efficiency is improved. Furthermore, the CFB structure offers the advantages of easy scale-up and the ability to continuously separate and recover the catalyst and generated carbon.

[0006] In particular, dry catalytic pyrolysis processes using fixed-bed or simple fluidized-bed reactors have limitations in that carbon accumulates on the catalyst surface over time, leading to catalyst deactivation and a gradual decrease in hydrogen yield. On the other hand, circulating fluidized-bed reactors can suppress catalyst deactivation by detaching carbon generated on the catalyst surface due to the continuous movement and collision of particles, and enable continuous regeneration of the catalyst through the circulating flow.

[0007] However, in the case of conventional circulating fluidized bed reactors, the presence of a mixture of catalyst and carbon particles can lead to problems such as catalyst loss, equipment clogging, and reduced reaction efficiency during the carbon removal process. Furthermore, since the catalyst and carbon particles dispersed after the reaction have non-uniform particle size and density, using centrifugal dust collectors or cyclones presents the problem of requiring multi-stage dust collection equipment depending on the particle characteristics. The problem to be solved

[0008] Embodiments of the present invention aim to provide a methane pyrolysis apparatus capable of realizing a selective separation phenomenon between carbon-catalyst particles by utilizing flow rate conditions of the catalyst minimum fluidization rate.

[0009] In addition, embodiments of the present invention aim to provide a methane pyrolysis apparatus capable of continuously separating solid carbon by overflow without loss of catalyst.

[0010] In addition, embodiments of the present invention aim to provide a methane pyrolysis device capable of effectively increasing reaction efficiency through continuous operation. means of solving the problem

[0011] According to an embodiment of the present invention, a methane pyrolysis apparatus may be provided, comprising: a fluidized bed reactor for pyrolyzing methane into a carbon mixture using a catalyst; a primary cyclone unit for primarily capturing carbon mixture particles discharged from the fluidized bed reactor; a feedback unit for resupplying the catalyst primarily captured in the primary cyclone unit to the fluidized bed reactor; and an overflow separation unit for separating primary carbon particles having a density lower than that of the catalyst from the carbon mixture primarily captured in the primary cyclone unit.

[0012] In addition, the present invention further includes a carbon tank section that receives and receives primary carbon particles from the overflow separation section; and a secondary cyclone section that collects secondary carbon particles discharged from the primary cyclone, wherein the outlet of the secondary cyclone section may be connected to the upper part of the carbon tank section.

[0013] Additionally, the feedback unit comprises: a particle transfer pipe connected between the lower part of the primary cyclone section and the fluidized bed reaction section to provide a movement path for the catalyst; a gas dispersion plate disposed at the lower part of the particle transfer pipe; and a gas supply line that provides gas to the particle transfer pipe.

[0014] Additionally, the overflow separation unit may include an overflow recovery line connected between the lower part of the primary cyclone unit and the carbon tank unit to provide a movement path for the primary carbon particles; and an overflow deflector formed protruding at the inlet of the overflow recovery line to guide the primary carbon particles to the overflow recovery line.

[0015] Additionally, the gas supply line may include a primary gas line that supplies a primary gas to the particle transfer tube for separating the primary carbon particles from the carbon mixture; and a secondary gas line that supplies a secondary gas to the particle transfer tube for moving the catalyst from the particle transfer tube to the fluidized bed reaction section.

[0016] In addition, the overflow separation unit may further include a purge gas supply line that supplies purge gas to the overflow recovery line to prevent carbon deposition within the overflow recovery line.

[0017] In addition, the first gas line can supply the first gas to the particle transfer pipe at a flow rate of 0.5 to 1 times the preset catalyst fluidization rate, and the second gas line can supply the second gas to the particle transfer pipe at a flow rate of 1 to 2 times the preset catalyst fluidization rate.

[0018] In addition, a gas dispersion hole may be formed in the overflow recovery line to inject and supply the purge gas from the purge gas supply line into the overflow recovery line.

[0019] In addition, the overflow recovery line may be connected at an angle to the side wall of the primary descending pipe of the primary cyclone section.

[0020] In addition, the overflow recovery line is formed to protrude in the vertical direction by penetrating the bottom surface of the feedback section, and the overflow deflector may be spaced apart from the upper part of the overflow recovery line. Effects of the invention

[0021] According to embodiments of the present invention, there is an effect of improving maintainability by avoiding the wear sealing problem of the feedback part.

[0022] In addition, according to the embodiments of the present invention, selective separation of carbon particles is possible through the control of the flow path and gas supply of the overflow separation unit, thereby enabling the suppression of excessive catalyst discharge.

[0023] In addition, according to the embodiments of the present invention, the device is suitable for continuous operation and has the effect of minimizing the accumulation of solids in the fluidized bed reaction section.

[0024] In addition, according to the embodiments of the present invention, by preventing clogging of the overflow recovery line of the overflow separation unit, the device can be operated stably.

[0025] In addition, according to the embodiments of the present invention, the hydrogen production efficiency of the device can be improved, and carbon recovery is easy.

[0026] In addition, according to embodiments of the present invention, an overflow separation section can be additionally configured on one side of a non-mechanical valve for particle recirculation of a conventional circulating fluidized bed reaction system, and the operation and maintenance of the device can be easily performed without a separate driving device.

[0027] In addition, according to the embodiments of the present invention, by directly separating and recovering high-purity carbon from the reaction system, additional catalytic carbon separation equipment is unnecessary, and system operation and maintenance costs can be reduced.

[0028] In addition, according to the embodiments of the present invention, by utilizing the density difference between catalyst particles and carbon particles for separation and discharge, the load on the dust collection equipment at the downstream end of the fluidized bed reaction unit can be reduced, and by making the particle size of the flyaway particles relatively uniform, the dust collection equipment can be installed relatively simply. Brief explanation of the drawing

[0029] FIG. 1 is a configuration diagram illustrating a methane pyrolysis apparatus according to a first embodiment of the present invention. FIG. 2 is a state diagram illustrating the movement flow of catalyst particles and carbon particles in a methane pyrolysis apparatus according to a first embodiment of the present invention. FIG. 3 is an enlarged view illustrating section "A" of FIG. 2. FIG. 4 is an enlarged view illustrating an overflow separation section and a feedback section of a methane pyrolysis apparatus according to a second embodiment of the present invention. FIG. 5 is an enlarged view illustrating an overflow separation section and a feedback section of a methane pyrolysis apparatus according to a third embodiment of the present invention. FIG. 6 is a graph illustrating the height of the carbon particle layer according to the fluidization gas flow rate ratio in a methane pyrolysis apparatus according to the present invention. FIG. 7 is a graph illustrating the pressure drop and mixing degree distribution of a mixture of carbon and catalyst-mimicking particles in a methane pyrolysis apparatus according to the present invention. Specific details for implementing the invention

[0030] Hereinafter, specific embodiments for implementing the technical concept of the present invention will be described in detail with reference to the drawings.

[0031] In addition, in describing the present invention, if it is determined that a detailed description of related known components or functions may obscure the essence of the invention, such detailed description is omitted.

[0032] Furthermore, when it is mentioned that one component is 'supplied' or 'transferred' to another component, it should be understood that while it may be supplied or transferred directly to that other component, there may also be other components present in between.

[0033] The terms used in this specification are used merely to describe specific embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise.

[0034] Furthermore, it should be noted in advance that the representations indicating direction in this specification are described based on the drawings, and may be expressed differently if the direction of the object changes. For the same reason, some components in the attached drawings are exaggerated, omitted, or schematically depicted, and the size of each component does not entirely reflect its actual size.

[0035] Additionally, terms including ordinal numbers, such as first, second, etc., may be used to describe various components, but such components are not limited by such terms. These terms are used solely for the purpose of distinguishing one component from another.

[0036] The meaning of "comprising" as used in the specification is to specify certain characteristics, regions, integers, steps, actions, elements, and / or components, and does not exclude the existence or addition of other specific characteristics, regions, integers, steps, actions, elements, components, and / or groups.

[0037] Hereinafter, a methane pyrolysis apparatus according to the present invention will be described in detail.

[0038] Referring to FIGS. 1 to 3, a methane pyrolysis device (10) according to one embodiment of the present invention can achieve a selective separation phenomenon between carbon and catalyst particles by utilizing flow rate conditions of the minimum catalyst fluidization rate. Such a methane pyrolysis device (10) may include a fluidized bed reaction section (100), a primary cyclone section (200), a feedback section (300), an overflow separation section (400), a carbon tank section (500), and a secondary cyclone section (600).

[0039] The fluidized bed reaction unit (100) can pyrolyze a gas containing methane into a carbon mixture using a catalyst. In this embodiment, the catalyst may mainly be Ni or Fe-based metal catalyst particles, and the density and particle size of the catalyst particles are each about 2.0 to 9.0 g / cm³. 3, may correspond to a range of 100 to 1,000 μm. The fluidized bed reaction section (100) may include a reaction tube (110) and a gas nozzle tube (120).

[0040] The reaction tube (110) may be provided in the form of a vertical cylindrical or rectangular circulating fluidized bed reactor. A methane pyrolysis reaction using a catalyst may be performed in the reaction tube (110). In the reaction tube (110), a flow may be formed in which the catalyst and carbon particles generated through the methane pyrolysis reaction rise together. The density and particle size of the carbon particles generated through the methane pyrolysis reaction are approximately 0.16 to 2.5 g / cm³, respectively. 3 It is at the level of 5 to 200 µm and can be significantly smaller and lighter than catalyst particles. The methane pyrolysis reaction can produce solid carbon along with hydrogen through Reaction Equation 1 below. High-purity separation and recovery of the solid carbon produced at this time, as well as its conversion into high-value-added products, are essential to ensure the economic viability of the process.

[0041] [Reaction Equation 1]

[0042] CH4(g) → 2H2(g) + C(s)(Equation 1)

[0043] The gas nozzle tube (120) can supply gas (reaction gas such as methane) to the reaction tube (110). The gas nozzle tube (120) may include a gas nozzle for supplying gas. The gas nozzle tube (120) can supply gas so as to maintain a transport velocity (Utr) greater than that of the catalyst particles. When the transport velocity of the gas supplied through the gas nozzle tube (120) is supplied at a rate greater than the transport velocity of the catalyst, the catalyst can be fluidized to form an upward flow together with the gas. At this time, carbon particles generated through the methane pyrolysis reaction also rise together with the catalyst and can be scattered and discharged to the upper side of the fluidized bed reaction section (100).

[0044] The primary cyclone section (200) can separate and collect solid particles contained in the gas using centrifugal force. In this embodiment, the primary cyclone section (200) can collect small carbon mixture particles discharged from the fluidized bed reaction section (100). The primary cyclone section (200) may include a primary cyclone (210), a primary descending pipe (220), and a primary rising pipe (230). The primary cyclone (210) may be provided in a conical shape. In the primary cyclone (210), small carbon mixture particles can be separated from the gas flow by centrifugal force. Small carbon mixture particles separated through the primary cyclone (210) can be moved to the primary descending pipe (220). The primary descending pipe (220) can guide small carbon mixture particles with a relatively high density discharged from the primary cyclone (210) downward. The first descending pipe (220) can be connected to the feedback section (300). The first rising pipe (230) can guide carbon mixture particles with a relatively low density discharged from the first cyclone (210) upward. The first rising pipe (230) can be connected to the second cyclone section (600).

[0045] The feedback section (300) can resupply the catalyst primarily captured in the primary cyclone section (200) to the fluidized bed reaction section (100). By maintaining the charge state of the particles (catalyst), the feedback section (300) can prevent gas backflow and ensure airtightness. When the carbon mixture captured in the feedback section (300) is filled to a certain amount or more, the catalyst particles can be recirculated to the fluidized bed reaction section (100) through the supply of gas. The feedback section (300) may include a particle transfer pipe (310), a gas dispersion plate (320), and a gas supply line (330).

[0046] The particle transfer tube (310) may be connected between the lower part of the primary cyclone section (200) and the fluidized bed reaction section (100) to provide a path for the movement of the catalyst. In this embodiment, the particle transfer tube (310) may be provided in the form of a loop-seal valve. The particle transfer tube (310) may be formed in a curved "U" shape. In the particle transfer tube (310), the gas supply flow rate is individually controlled under conditions of being below (0.5 to 1 Umf) and above (>1 Umf) the minimum fluidization velocity (Umf) of the catalyst, thereby maintaining the particle filling state and controlling the amount of particle recirculation. A first chamber (311) and a second chamber (312) may be provided at the lower part of the particle transfer tube (310). The first chamber (311) and the second chamber (312) may be spaces where gas supplied through the gas supply line (330) can be temporarily received. The first chamber (311) and the second chamber (312) may be partitioned in the particle transfer tube (310) by a gas dispersion plate (320). Gas within the first chamber (311) and the second chamber (312) may be transferred to the internal space of the particle transfer tube (310) through the gas dispersion plate (320). The first chamber (311) may be positioned at the inlet side of the particle transfer tube (310) adjacent to the overflow separation section (400), and the second chamber (312) may be positioned at the outlet side of the particle transfer tube (310) adjacent to the fluidized bed reaction section (100).

[0047] The gas dispersion plate (320) can disperse gas and supply it to the particle transfer tube (310). A plurality of gas holes capable of dispersing gas may be formed in the gas dispersion plate (320). The gas dispersion plate (320) may be positioned at the bottom of the particle transfer tube (310). The gas dispersion plate (320) may be positioned above the first chamber (311) and the second chamber (312). The outer diameter of the gas dispersion plate (320) may correspond to the lower inner diameter of the particle transfer tube (310).

[0048] The gas supply line (330) can supply gas to the particle transfer tube (310). The gas supply line (330) may include a primary gas line (331) and a secondary gas line. The primary gas line (331) can supply primary gas to the particle transfer tube (310) for separating primary carbon particles from a carbon mixture. The primary gas line (331) can supply primary gas to the inlet side of the particle transfer tube (310) through the first chamber (311). For example, the primary gas line (331) can supply primary gas to the particle transfer tube (310) at a flow rate of 0.5 to 1 times the preset catalyst fluidization rate. When primary gas is supplied to the particle transfer pipe (310) through the primary gas line (331), relatively small and light carbon particles (floatsam) can be fluidized under low flow rate conditions and moved to the upper part of the particle layer, while relatively large and heavy catalyst particles (jetsam) remain at the lower part. At this time, the carbon particle layer formed on the upper part of the catalyst layer can expand due to the gas flow and increase up to about twice the height of the fixed bed (L0), and the height of the catalyst layer can be maintained relatively constant from the height of the fixed bed. The secondary gas line (332) can supply secondary gas to the particle transfer pipe (310) to move the catalyst from the particle transfer pipe (310) to the fluidized bed reaction section (100). The secondary gas line (332) can supply secondary gas to the outlet side of the particle transfer pipe (310) through the second chamber (312). For example, the secondary gas line (332) can supply secondary gas to the particle transfer pipe (310) at a flow rate of 1 to 2 times the preset catalyst fluidization rate. When secondary gas is supplied to the particle transfer pipe (310) through the secondary gas line (332), the catalyst particles filled in the particle transfer pipe (310) can be fluidized and recirculated to the fluidized bed reaction section (100).The amount of catalyst recirculation can be controlled by adjusting the flow rate of the secondary gas, and by maintaining the amount of catalyst discharged from the fluidized bed reaction section (100) and the amount of recirculation at a constant level, continuous operation of the methane pyrolysis device (10) is possible. In addition, if the amount of catalyst charged in the particle transfer pipe (310) is maintained stably, uniformity of the layer height can be ensured.

[0049] The overflow separation unit (400) can separate primary carbon particles with a density lower than that of the catalyst from the carbon mixture primarily captured in the primary cyclone unit (200). When particles are filled into the particle transfer pipe (310), if gas is supplied at a flow rate condition lower than the minimum fluidization velocity of the catalyst, the overflow separation unit (400) can move only carbon particles with a density lower than that of the catalyst to the upper side of the particle transfer pipe (310), thereby enabling layer separation between the catalyst and the carbon particles. Once layer separation between the catalyst and the carbon particles is achieved, the carbon particles can be separated and discharged through the overflow separation unit (400). The discharged carbon particles can be moved to the carbon tank unit (500). The overflow separation unit (400) may include an overflow recovery line (410), an overflow deflector (420), and a purge gas supply line (430).

[0050] The overflow recovery line (410) can guide carbon particles selected from the particle transfer pipe (310) to the carbon tank section (500). The overflow recovery line (410) can provide a path for the movement of primary carbon particles. The overflow recovery line (410) can be placed on the upper side wall of the particle transfer pipe (310). The overflow recovery line (410) can be connected between the upper side wall of the transfer pipe and the carbon tank section (500). A gas dispersion hole (411) can be formed in the overflow recovery line (410) to inject and supply purge gas from the purge gas supply line (430) into the inside of the overflow recovery line (410). The overflow recovery line (410) can be connected at an angle to the side wall of the particle transfer pipe (310) of the fluidized bed reaction section (100).

[0051] The overflow deflector (420) can guide primary carbon particles into the overflow recovery line (410). The overflow deflector (420) can prevent the inflow of catalyst particles supplied through the primary downpipe (220) into the overflow recovery line (410) and can suppress carbon deposition and blockage within the overflow recovery line (410). The overflow deflector (420) can be positioned at the top of the overflow recovery line (410). The overflow deflector (420) can be formed protruding from the inlet of the overflow recovery line (410). The overflow deflector (420) can be formed extending downwardly inwardly from the upper side wall of the particle transfer pipe (310).

[0052] The purge gas supply line (430) can suppress carbon deposition and blockage within the overflow recovery line (410) by supplying purge gas to the inner wall of the overflow recovery line (410). The purge gas supply line (430) can be connected to the upper side wall of the overflow recovery line (410).

[0053] The carbon tank section (500) can receive and accommodate primary carbon particles from the overflow separation section (400) and receive and accommodate secondary carbon particles from the secondary cyclone. The density of the secondary carbon particles may be lower than the density of the primary carbon particles. The carbon tank section (500) may be connected to the overflow separation section (400) and the secondary cyclone, respectively.

[0054] The secondary cyclone section (600) can collect secondary carbon particles discharged from the primary cyclone. The outlet of the secondary cyclone section (600) can be connected to the upper part of the carbon tank section (500). The secondary cyclone section (600) may include a secondary cyclone (610), a secondary descending pipe (620), and a secondary rising pipe (630). The secondary cyclone (610) may be provided in a cylindrical shape. In the secondary cyclone (610), secondary carbon particles can be separated from the gas flow caused by centrifugal force. The secondary carbon particles separated through the secondary cyclone (610) can be moved to the secondary descending pipe (620). The secondary descending pipe (620) can guide the secondary carbon particles discharged from the secondary cyclone (610) downward. The second descending pipe (620) can be connected to the carbon tank section (500). The second rising pipe (630) can discharge fine particles with a relatively low density upward from the second cyclone (610).

[0055] Referring to FIG. 4, in the methane pyrolysis device (10) according to the second embodiment of the present invention, the feedback unit (300) can be connected vertically to the fluidized bed reaction unit (100). In describing the second embodiment, since there is a difference in the arrangement configuration of the feedback unit (300) compared to the first embodiment described above, the following description focuses on the differences, and the same descriptions and reference numerals are used by reference.

[0056] The feedback section (300) can resupply the catalyst primarily captured in the primary cyclone section (200) to the fluidized bed reaction section (100). By maintaining the charge state of the particles (catalyst), the feedback section (300) can prevent gas backflow and ensure airtightness. The feedback section (300) may include a particle transfer pipe (310) and a gas supply line (330).

[0057] A particle transfer tube (310) can be connected between the lower part of the primary cyclone section (200) and the fluidized bed reaction section (100) to provide a path for the catalyst to move. In this embodiment, the particle transfer tube (310) can be provided in the form of an L-valve. The particle transfer tube (310) can be formed in a curved "L" shape. In the particle transfer tube (310), the gas supply flow rate is individually controlled under conditions of being below (0.5 to 1 Umf) and above (>1 Umf) the minimum fluidization rate (Umf) of the catalyst, thereby maintaining the particle filling state and controlling the amount of particle recirculation.

[0058] The gas supply line (330) can supply gas to the particle transfer pipe (310). The gas supply line (330) may include a primary gas line (331) and a secondary gas line. The primary gas line (331) can supply primary gas to the particle transfer pipe (310) to move a catalyst from the particle transfer pipe (310) to the fluidized bed reaction section (100). The primary gas line (331) may be positioned at the inlet side of the particle transfer pipe (310) adjacent to the overflow separation section (400). The secondary gas line (332) can supply secondary gas to the particle transfer pipe (310) to separate primary carbon particles from the carbon mixture. The secondary gas line (332) may be positioned at the outlet side of the particle transfer pipe (310) adjacent to the fluidized bed reaction section (100).

[0059] Referring to FIG. 5, in the methane pyrolysis device (10) according to the third embodiment of the present invention, the overflow recovery line (410) of the overflow separation unit (400) may be formed to protrude in the vertical direction by penetrating the bottom surface of the feedback unit (300). In describing the third embodiment, since there is a difference in the arrangement configuration of the overflow separation unit (400) when compared to the first embodiment described above, the following description will focus on the differences, and the same descriptions and reference numerals will be used by reference.

[0060] The overflow separation unit (400) can separate primary carbon particles with a density lower than that of the catalyst from the carbon mixture primarily captured in the primary cyclone unit (200). When particles are filled into the particle transfer pipe (310), if gas is supplied under a flow rate condition lower than the minimum fluidization velocity of the catalyst, the overflow separation unit (400) can move only carbon particles with a density lower than that of the catalyst to the upper side of the particle transfer pipe (310), thereby enabling layer separation between the catalyst and the carbon particles. Once layer separation between the catalyst and the carbon particles is achieved, the carbon particles can be separated and discharged through the overflow separation unit (400). The discharged carbon particles can be transferred to the carbon tank unit (500). The overflow separation unit (400) may include an overflow recovery line (410) and an overflow deflector (420).

[0061] The overflow recovery line (410) can guide carbon particles selected from the particle transfer pipe (310) to the carbon tank section (500). The overflow recovery line (410) can provide a movement path for the primary carbon particles. The overflow recovery line (410) can be formed to protrude in the vertical direction by penetrating the bottom surface of the feedback section (300). The overflow recovery line (410) can be connected between the lower part of the transfer pipe and the carbon tank section (500).

[0062] The overflow deflector (420) can guide primary carbon particles into the overflow recovery line (410). The overflow deflector (420) can prevent the inflow of catalyst particles supplied through the primary downpipe (220) into the overflow recovery line (410) and can suppress carbon deposition and blockage within the overflow recovery line (410). The overflow deflector (420) can be spaced apart from the upper part of the overflow recovery line (410).

[0063] The operation and effects of a methane pyrolysis device having the configuration described above will be explained below.

[0064] First, when a gas (reaction gas such as methane) is supplied to the lower part of the fluidized bed reaction section (100) filled with catalyst particles at a rate greater than the catalyst transport velocity, the catalyst can be fluidized to form an upward flow together with the gas. At this time, carbon particles generated through the methane pyrolysis reaction in the fluidized bed reaction section (100) also rise together with the catalyst and can be scattered and discharged through the upper outlet of the fluidized bed reaction section (100).

[0065] Small carbon mixture particles discharged along with gas can be separated and collected from the gaseous flow through the primary cyclone section (200) and can be moved to the feedback section (300) through the primary descending pipe (220) of the primary cyclone section (200). When a certain amount of catalyst-carbon mixture is filled in the feedback section (300), primary gas is supplied to the particle transfer pipe (310) at a flow rate condition of 0.5 to 1 times the minimum catalyst fluidization speed, thereby inducing layer separation of the catalyst and carbon particles within the small carbon mixture particles. In other words, relatively small and light carbon particles (floatsam) can be fluidized under low flow rate conditions and moved to the upper part of the particle layer, while relatively large and heavy catalyst particles (jetsam) can remain at the lower part of the particle transfer pipe (310). At this time, the carbon particle layer formed on the upper part of the catalyst layer expands due to the gas flow and increases to about twice the height of the fixed layer (L0), and the height of the catalyst layer can be maintained relatively constant at the height of the fixed layer.

[0066] By supplying a secondary gas to the particle transfer pipe (310) at a flow rate of 1 to 2 times the catalyst fluidization rate, the catalyst particles filled in the particle transfer pipe (310) can be fluidized and recirculated to the fluidized bed reaction section (100) through the discharge pipe. The amount of catalyst recirculation through the particle transfer pipe (310) can be controlled by adjusting the flow rate of the secondary gas. Continuous operation is possible if the amount of catalyst discharged from the fluidized bed reaction section (100) and the amount of recirculation are maintained at a constant level. Additionally, uniformity of the layer height can be ensured by stably maintaining the amount of catalyst filled in the particle transfer pipe (310). As the reaction proceeds, if small carbon mixture particles are continuously supplied, the catalyst particles pass through the expanded carbon particle layer and sink to the bottom, while the carbon particles remain on the upper part of the catalyst layer. At this time, the carbon particles can be selectively separated and discharged through the carbon overflow separation section (400) located at the top of the particle transfer pipe (310). The connection portion of the overflow separation section (400) connected to the particle transfer pipe (310) is installed at a height formed by the expansion of the carbon particle layer (approximately 1.5 to 2 times the height of the initial fixed bed, 1.5 to 2 L0), thereby effectively separating and discharging carbon particles suspended on the upper surface of the catalyst layer and stably maintaining physical separation from the catalyst particles. Under conditions where the supply flow rate of the primary gas is sufficiently fast (approximately 2 to 3 times the minimum catalyst fluidization speed, 2 to 3 Umf), the mixture within the particle transfer pipe (310) may also be fluidized, and accordingly, mixing between the catalyst and carbon particles may proceed, making particle separation difficult. As a result, small carbon mixture particles may be re-supplied to the fluidized bed reaction section (100) through the particle transfer pipe (310) without being separated.

[0067] In the overflow separation section (400), an overflow deflector (420) may be installed at the end of the overflow recovery line (410) to prevent catalyst particles supplied through the primary descending pipe (220) from flowing into the overflow recovery line (410). Additionally, since a purge gas supply line (430) is provided in the overflow recovery line (410), the deposition and clogging of carbon within the overflow recovery line (410) can be prevented. In this embodiment, the comparison of carbon-mimicking particles, catalyst-mimicking particles, and minimum fluidization rates is summarized in the tables below as Tables 1, 2, and 3.

[0068] [Table 1]

[0069]

[0070] [Table 2]

[0071]

[0072] [Table 3]

[0073]

[0074] Meanwhile, as a result of the fluidization operation of the carbon mixture, it was confirmed that when fluidization gas is supplied to a mixture of carbon and catalyst-mimicking particles and the flow rate is gradually increased, the fluidization of the carbon particles proceeds first, and under flow rate conditions exceeding the minimum fluidization velocity of the carbon particles, the carbon particles float and layer separation occurs with the catalyst particle layer.

[0075] Referring to Figure 6, as the flow rate of the fluidizing gas increases, the carbon particle layer expands, and under the condition of approximately 1.5 times the minimum fluidizing velocity of the carbon particles (U / Umf, carbon=1.5), the height of the carbon layer increases to approximately 2.6 times (120-130 mm) compared to the initial height, and then maintains a constant height.

[0076] The mixing index between carbon-catalyst-mimicking particles can be determined by measuring the differential pressure between the carbon particle layer and the catalyst particle layer and the total differential pressure according to Equations 1 and 2 below. If the mixing index (MI) is 1, it can be determined to be in a completely mixed state, and if it is 0, it can be determined to be in a completely separated state.

[0077] [Formula 1]

[0078]

[0079] [Equation 2]

[0080]

[0081] Referring to Fig. 7, the separation of the catalyst layer and the carbon layer can be maintained up to the minimum fluidization rate condition of the catalyst-mimicking particles (U / Umf,catalyst≤1), and at flow rate conditions exceeding the minimum fluidization rate (U / Umf,catalyst>1), mixing between particles begins to occur at the interface between the catalyst layer and the carbon layer, and as the flow rate increases, the degree of mixing may also increase, and separation between the carbon and catalyst particles may become difficult.

[0082] As described above, the present invention can provide the effect of improving maintainability by avoiding the wear sealing problem of the feedback part.

[0083] In addition, the present invention can provide the effect of suppressing excessive catalyst discharge by enabling selective separation of carbon particles through the control of the flow path and gas supply of the overflow separation unit.

[0084] In addition, the present invention is suitable for continuous operation of the device and can provide the effect of minimizing the accumulation of solids in the fluidized bed reaction section.

[0085] In addition, the present invention can provide the effect of enabling stable operation of the device by preventing clogging of the overflow recovery line of the overflow separation unit.

[0086] In addition, the present invention can improve the hydrogen production efficiency of the device and provide the effect of facilitating carbon recovery.

[0087] In addition, the present invention enables the additional configuration of an overflow separation section on one side of a non-mechanical valve for particle recirculation in a conventional circulating fluidized bed reaction system, and can provide the effect of facilitating the operation and maintenance of the device without a separate driving device.

[0088] In addition, the present invention can provide the effect of eliminating the need for additional catalytic carbon separation equipment and reducing system operation and maintenance costs by directly separating and recovering high-purity carbon from the reaction system.

[0089] In addition, the present invention can reduce the load on the dust collection equipment downstream of the fluidized bed reaction unit by utilizing the density difference between catalyst particles and carbon particles for separation and discharge, and can provide the effect of enabling the dust collection equipment to be installed relatively simply by making the particle size of airborne particles relatively uniform.

[0090] Although the embodiments of the present invention have been described above as specific embodiments, they are merely examples and the present invention is not limited thereto, but should be interpreted as having the broadest scope in accordance with the technical concept disclosed in this specification. Those skilled in the art may implement patterns of shapes not specified by combining or substituting the disclosed embodiments, and this also does not deviate from the scope of the present invention. Furthermore, those skilled in the art may easily modify or alter the disclosed embodiments based on this specification, and it is evident that such modifications or alterations also fall within the scope of the rights of the present invention. Explanation of the symbols

[0091] 10: Methane Pyrolysis Unit 100: Fluidized Bed Reactor 200: Primary Cyclone Section 300: Feedback Section 310: Particle Transfer Pipe 320: Gas Dispersion Plate 330: Gas Supply Line 331: Primary Gas Line 332: Secondary Gas Line 400: Overflow Separator 410: Overflow Recovery Line 411: Gas Dispersion Hole 420: Overflow Deflector 430: Purge Gas Supply Line 500: Carbon Tank Section 600: Secondary Cyclone Section

Claims

Claim 1 A fluidized bed reactor for thermally decomposing methane into a carbon mixture using a catalyst; a primary cyclone section connected to the fluidized bed reactor to primarily capture carbon particles and catalyst particles contained in the carbon mixture; a feedback section connecting the primary cyclone section and the fluidized bed reactor to resupply the catalyst particles primarily captured in the primary cyclone section to the fluidized bed reactor; and an overflow separation section connected to the lower part of the primary cyclone section to separate primary carbon particles having a density lower than that of the catalyst particles from the carbon mixture primarily captured in the primary cyclone section, wherein the feedback section includes a particle transfer pipe; and a gas supply line for supplying gas to the particle transfer pipe, wherein the gas supply line is a primary gas line that supplies primary gas to the particle transfer pipe for separating the primary carbon particles from the carbon mixture. A methane pyrolysis apparatus comprising a secondary gas line for supplying a secondary gas to the particle transfer pipe to move catalyst particles from the particle transfer pipe to the fluidized bed reaction section. Claim 2 A methane pyrolysis device according to claim 1, further comprising: a carbon tank section for receiving and accommodating primary carbon particles from the overflow separation section; and a secondary cyclone section for collecting secondary carbon particles discharged from the primary cyclone, wherein the outlet of the secondary cyclone section is connected to the upper part of the carbon tank section. Claim 3 A methane pyrolysis apparatus according to claim 1, wherein the feedback unit further comprises a gas dispersion plate disposed at the lower part of the particle transfer tube. Claim 4 A methane pyrolysis apparatus according to claim 1, wherein the overflow separation section comprises: an overflow recovery line connected between the lower part of the primary cyclone section and the carbon tank section to provide a movement path for the primary carbon particles; and an overflow deflector formed protruding at the inlet of the overflow recovery line to guide the primary carbon particles to the overflow recovery line. Claim 5 delete Claim 6 In claim 4, the overflow separation unit further comprises a purge gas supply line that supplies purge gas to the overflow recovery line to prevent carbon deposition in the overflow recovery line, a methane pyrolysis device. Claim 7 A methane pyrolysis apparatus according to claim 1, wherein the flow rate of the primary gas supplied to the particle transfer pipe through the primary gas line is at least smaller than the flow rate of the secondary gas supplied to the particle transfer pipe through the secondary gas line. Claim 8 A methane pyrolysis device according to claim 6, wherein the overflow recovery line has a gas dispersion hole formed therein for injecting and supplying the purge gas of the purge gas supply line into the overflow recovery line. Claim 9 In claim 4, the methane pyrolysis device, wherein the overflow recovery line is connected obliquely to the side wall of the primary descending pipe of the primary cyclone section. Claim 10 A methane pyrolysis device according to claim 4, wherein the overflow recovery line is formed to protrude in the vertical direction through the bottom surface of the feedback section, and the overflow deflector is spaced apart from the upper end of the overflow recovery line.

Images