System and method for manufacturing clean hydrogen and NANO carbon using microwave plasma

Abstract

The present invention relates to a clean hydrogen and nanocarbon manufacturing system and method using microwave plasma. The clean hydrogen and nanocarbon manufacturing system according to the present invention comprises a swirler (400) that swirls plasma generating gas and supplies it to a torch (500); a torch (500) that generates plasma by irradiating the swirling plasma generating gas with microwaves; and a reactor (700) that decomposes natural gas with the plasma generated from the torch (500). The swirler (400) is formed with one inlet (410) formed in the center of the front section, a plurality of discharge ports (420) formed inside, and a spiral groove (430) formed on the outer circumference. The clean hydrogen and nanocarbon manufacturing system and method according to the present invention can appropriately adjust the contact time between the plasma generating gas and microwaves in the torch (500) by varying the number of discharge ports (420) of the swirler (400).

Description

Technology Field

[0001] The present invention relates to a system and method for producing clean hydrogen and nanocarbon using microwave plasma, and more specifically, to a microwave plasma-based system and method for producing clean hydrogen and nanocarbon that efficiently produces high-purity hydrogen without generating carbon dioxide from natural gas by maintaining sufficient contact between the plasma generating gas and natural gas during the step of supplying the plasma generating gas to a torch. Background Technology

[0002] Plasma is a type of ionized gas with electrical conductivity that is composed of ions, electrons, free radicals, and various chemical species in ground and excited states, and thus possesses very high reactivity.

[0003] Such plasmas can be divided into thermal plasma and low-temperature plasma, and atmospheric pressure plasma realized by microwave discharge—that is, microwave plasma—is a type of low-temperature plasma.

[0004] Microwave plasma systems can generate high-ionization plasma at atmospheric pressure without excessive heating, thereby reducing equipment installation costs associated with vacuum maintenance. Furthermore, since discharge is possible without internal electrodes, the system structure is simple and easy to operate. It also offers the advantage of minimal interference from electrical disturbances.

[0005] Microwave plasma can be generated by irradiating a plasma generating gas with microwaves at atmospheric pressure, and natural gas can be reformed by decomposing it into hydrogen and carbon through the high thermal energy of the generated plasma.

[0006] Inert gases (e.g., argon) are widely used as plasma generating gases, and diatomic molecules (e.g., nitrogen, oxygen, air) and triatomic molecules (e.g., water vapor, carbon dioxide) are also used, but methane (natural gas) is a pentatomic molecule, making it difficult to generate plasma. In this case, methane (natural gas) can be mixed with an inert gas (e.g., argon) and used as a plasma generating gas.

[0007] Generally, plasma generating gas is supplied to the torch while swirling, which is a very important process for generating plasma by efficiently bringing the plasma generating gas and microwaves into contact at the torch.

[0008] However, conventional swirlers inject plasma generating gas diagonally from multiple inlets (Korean Registered Patent Publication No. 10-1752979) or swirl the plasma generating gas by installing plate-shaped guide plates (Korean Published Patent Publication No. 10-2023-0000606), which presents a problem in commercial plants using multiple swirlers and torches, as the piping lines are complex and maintenance is difficult.

[0009] In addition, conventional swirlers fix the quartz tube surrounding the swirler to the bottom with a support ledge or the like, but the fixation is not perfect, causing problems such as the quartz tube moving. Furthermore, since the entire torch must be disassembled and the swirler and quartz tube separated to replace the quartz tube, repairs take a long time and the repair method is complicated, so improvements are urgently needed. Prior art literature

[0010] Republic of Korea Published Patent Application No. 10-2023-0000606 (Jan. 3, 2023) Republic of Korea Registered Patent Application No. 10-1752979 (June 26, 2017) Republic of Korea Published Patent Application No. 10-2013-0115924 (Oct. 22, 2013) Republic of Korea Published Patent Application No. 10-2005-0046358 (May 18, 2005) The problem to be solved

[0011] The present invention relates to a microwave plasma type clean hydrogen and nanocarbon manufacturing system and method, in which a plasma generating gas is swirled by a swirler and supplied to a torch to efficiently bring the plasma generating gas and microwaves into contact at the torch. It was devised to solve the aforementioned problems associated with conventional swirlers. The objective of the present invention is to provide a microwave plasma type clean hydrogen and nanocarbon manufacturing system and method equipped with a swirler for a microwave plasma system, which is suitable for the commercialization of systems utilizing microwave plasma, as the piping line is not complex and maintenance is easy.

[0012] Another objective of the present invention is to provide a microwave plasma-based clean hydrogen and nanocarbon manufacturing system and manufacturing method equipped with a swirl device for a microwave plasma system, wherein there is no movement of the quartz tube surrounding the swirl device, disassembly and assembly are easy to reduce maintenance time, and replacement is easy when the capacity of the microwave plasma system changes.

[0013] Another objective of the present invention is to provide a microwave plasma-based clean hydrogen and nanocarbon manufacturing system and manufacturing method equipped with a swirl device for a microwave plasma system that can easily control the contact time between the plasma generating gas in the torch and the microwave. means of solving the problem

[0014] A clean hydrogen and nanocarbon manufacturing system using microwave plasma according to one embodiment of the present invention comprises: a swirler that supplies plasma generating gas to a torch while swirling it; a torch that generates plasma by irradiating the swirling plasma generating gas with microwaves; and a reactor that decomposes natural gas with the plasma generated from the torch, wherein the swirler is provided with one inlet formed in the center of the front end, a plurality of discharge ports formed inside, and a spiral groove formed on the outer circumference, and when the plasma generating gas is injected into the one inlet formed in the center of the front end of the swirler and discharged through the plurality of discharge ports formed inside, the plasma generating gas is separated into multiple branches and introduced into the torch while swirling along the spiral groove formed on the outer circumference of the swirler.

[0015] In one embodiment, the plasma generating gas consists of nitrogen and natural gas.

[0016] In one embodiment, the contact time between the plasma generating gas in the torch and the microwave is controlled by varying the number of discharge ports of the swirl device.

[0017] In one embodiment, a pre-reactor is further provided to decompose natural gas by utilizing the high activity of plasma supplied directly from a torch and the high temperature of the plasma in the preceding stage of the reactor.

[0018] A method for producing clean hydrogen and nanocarbon using microwave plasma according to one embodiment of the present invention comprises the steps of: supplying a plasma generating gas to a torch while swirling it with a swirler; generating microwave plasma by irradiating the plasma generating gas with microwaves at the torch; and decomposing natural gas with the microwave plasma in a pre-reactor and a reactor, wherein the step of supplying the plasma generating gas to a torch while swirling it with a swirler comprises the step of injecting the plasma generating gas into a single inlet formed in the center of the front end of the swirler and discharging it through a plurality of discharge ports formed inside, so that the plasma generating gas is separated into multiple branches and introduced into the torch while swirling along a spiral groove formed on the outer circumference of the swirler.

[0019] In one embodiment, the step of supplying the plasma generating gas to the torch while swirling it with a swirler includes the step of varying the number of discharge ports of the swirler so as to control the contact time between the plasma generating gas and the microwave in the torch.

[0020] In one embodiment, the step of decomposing natural gas in the prereactor comprises contacting natural gas, which is preheated in a heat recovery facility and supplied to the prereactor through a nozzle, with plasma gas that is supplied directly from a torch to the prereactor in a state where electron movement is most active.

[0021] In one embodiment, the step of decomposing natural gas in the reactor comprises the step of reacting the unreacted natural gas once more by concentrating the temperature in the center of the reactor through swirling the exhaust gas and the plasma flame at an angle of 15 to 45° toward the inner wall of the reactor during the process of introducing the gas discharged after primary decomposition in the pre-reactor into the reactor together with the plasma flame.

[0022] A swirl device for a microwave plasma system according to one embodiment of the present invention is composed of one inlet formed in the center of the front section, a plurality of discharge ports formed inside, and a spiral groove formed on the outer circumference. When a plasma generating gas is injected into the one inlet (410) formed in the center of the front section of the swirl device (400) and discharged through the plurality of discharge ports (430) formed inside, the plasma generating gas is separated into multiple branches and functions to be introduced into a torch (500) while swirling along the spiral groove (430) formed on the outer circumference of the swirl device (400).

[0023] In addition, a swirl device for a microwave plasma system according to one embodiment of the present invention has the function of controlling the contact time between the plasma generating gas in the torch and the microwave by varying the number of discharge ports. Effects of the invention

[0024] The present invention has the effect of providing a microwave plasma-based clean hydrogen and nanocarbon manufacturing system and manufacturing method equipped with a swirl device for a microwave plasma system, which is suitable for commercialization of a system utilizing microwave plasma because the piping line is not complex and maintenance is easy.

[0025] In addition, the present invention has the effect of providing a microwave plasma-type clean hydrogen and nanocarbon manufacturing system and manufacturing method equipped with a swirler for a microwave plasma system, wherein there is no movement of the quartz tube surrounding the swirler, disassembly and assembly are easy to shorten maintenance time, and replacement is easy when the capacity of the microwave plasma system changes.

[0026] In addition, the present invention relates to the contact time between the plasma generating gas and the microwave in the torch. The invention has the effect of providing a microwave plasma-based clean hydrogen and nanocarbon manufacturing system and manufacturing method equipped with a swirl device for an easily adjustable microwave plasma system. Brief explanation of the drawing

[0027] FIG. 1 is a process flow diagram of a clean hydrogen and nanocarbon manufacturing system using microwave plasma according to one embodiment of the present invention. FIG. 2 is a process block diagram of a clean hydrogen and nanocarbon manufacturing system using microwave plasma according to one embodiment of the present invention. FIG. 3 is a schematic diagram showing the connection relationship between a swirl device for a microwave plasma system and its peripheral devices according to one embodiment of the present invention. FIG. 4 is a schematic diagram showing a swirl device for a microwave plasma system according to one embodiment of the present invention, and is a cross-sectional view. FIG. 5 is a schematic diagram showing a swirl device for a microwave plasma system according to one embodiment of the present invention, and is a cross-sectional view. FIG. 6 is a schematic diagram showing a column of fire formed in the center of the interior by the plasma flame of a torch in a reactor of a clean hydrogen and nanocarbon manufacturing system using microwave plasma according to one embodiment of the present invention, and is a cross-sectional view. FIG. 7 is a schematic diagram showing a column of fire formed in the center of the interior by the plasma flame of a torch in a reactor of a clean hydrogen and nanocarbon manufacturing system using microwave plasma according to one embodiment of the present invention, and is a longitudinal cross-sectional view. Specific details for implementing the invention

[0028] Hereinafter, an embodiment of the present invention will be described in detail with reference to the attached drawings.

[0029] In the attached drawings, the shapes and detailed configurations of the device elements have been simplified for illustrative purposes, and the same reference numerals in each drawing represent the same parts.

[0030] In describing the present invention, specific descriptions of related known functions or configurations have been omitted where it is determined that such descriptions could unnecessarily obscure the essence of the invention.

[0031] Furthermore, the terms used in this specification are used to appropriately describe preferred embodiments of the present invention, and these may vary depending on the intent of the user or operator or case law in the field to which the present invention belongs. Accordingly, the definitions of these terms should be based on the content throughout this specification.

[0032] Additionally, the term "natural gas" used in describing the present invention includes biogas.

[0033] FIG. 1 is a process flow diagram of a clean hydrogen and nanocarbon manufacturing system using microwave plasma according to one embodiment of the present invention, and FIG. 2 is a process block diagram.

[0034] A clean hydrogen and nanocarbon manufacturing system using microwave plasma according to one embodiment of the present invention comprises a pretreatment device (200) for removing impurities in natural gas (100), a heat recovery facility (300) for preheating natural gas that has passed through the pretreatment device (200), a swirler (400) for swirling the gases before supplying the plasma generating gas, which consists of nitrogen gas (N2) and natural gas, to a microwave plasma torch (500), a torch (500) for generating plasma by irradiating microwaves onto the swirling natural gas and nitrogen gas, and a prereactor (600) and a reactor (700) for decomposing natural gas by introducing it into the high-temperature gas in a plasma state.

[0035] The process of a clean hydrogen and nanocarbon manufacturing system using microwave plasma according to one embodiment of the present invention is described in more detail as follows.

[0037] [ Pretreatment of natural gas, preheating, and supply of plasma generating gas to the torch ]

[0038] First, natural gas (100), such as liquefied natural gas or biogas, is supplied and adjusted to a pressure (5 to 10 bar) required for a subsequent process, and then moisture, hydrogen sulfide, sulfur oxides, carbon dioxide, and other impurities in the natural gas are removed in a pretreatment device (200).

[0039] Natural gas that has undergone a pretreatment process is heat-exchanged with the outlet gas (600~700℃) of the reactor (700) in the heat recovery facility (300) to preheat it to 200~250℃, and then supplied to the swirl device (400) and the pre-reactor (600) connected to the front end of the torch (500).

[0040] When the plasma generating gas, composed of a mixture of natural gas and nitrogen gas (N2) that has undergone the preceding pretreatment process, is introduced into the swirler (400), the plasma generating gas swirls and is supplied to the torch (500). Nitrogen gas (N2) can be replaced with argon gas (Ar).

[0041] FIG. 3 is a schematic diagram showing the connection relationship between a swirl device for a microwave plasma system and its peripheral devices according to one embodiment of the present invention.

[0042] FIG. 4 is a schematic diagram showing a swirl device for a microwave plasma system according to one embodiment of the present invention, which is a longitudinal section, and FIG. 5 is a transverse section.

[0043] A swirl device (400) according to one embodiment of the present invention is composed of one inlet (410) formed in the center of the front section, a plurality of discharge ports (420) formed inside, and a spiral groove (430) formed on the outer circumference surface, and FIG. 5 illustrates a swirl device having three discharge ports (420).

[0044] According to one embodiment of the present invention, a swirl device (400) is surrounded by a quartz tube (510), and a plasma generating gas is injected into the inlet (410) of the swirl device (400) and comes out through the discharge port (420). When the gas is injected into the torch (500) in a swirled state through a flow path formed between the quartz tube (510) surrounding the swirl device (400) and a spiral groove (430), it comes into contact with a microwave (41) introduced into the torch (500) through a microwave waveguide (40) to generate plasma.

[0045] According to one embodiment of the present invention, when a plasma generating gas is injected into a single inlet (410) formed in the center of the front end of a swirl device (400) and discharged through a plurality of discharge ports (430) formed inside, the plasma generating gas is separated into multiple branches and proceeds while swirling along a spiral flow path (spiral groove: 430) in the shape of a groove formed on the outer circumference of the swirl device (400), thereby creating an efficient swirl gas (450) in which the contact time between the swirl gas (450: plasma generating gas) and the microwave in the torch (500) can be appropriately controlled, and by introducing this efficient swirl gas (450) into the torch (500), plasma can be efficiently generated.

[0046] In one embodiment of the present invention, the swirl device (400) has a number of spiral grooves (430) and a swirl angle of spiral grooves (430) that vary according to the number of discharge ports (420), and accordingly, the swirl rotation speed and flow velocity of the swirl gas vary, so the contact time between the plasma generating gas and the microwave in the torch (500) can be efficiently controlled using this. .

[0047] The contact time between the plasma generating gas and the microwave in the torch (500) is the torch's According to one embodiment of the present invention, if the time the plasma generating gas in the torch (500) comes into contact with the microwave is shorter than 0.5 ms (millisecond: 1 ms = 1 / 1,000 sec), the plasma generating gas passes through the reaction region too quickly, so the plasma is not formed well, and if the contact time exceeds 20 ms (if the flow rate of the plasma generating gas passing through the reaction region is too slow), the high-temperature plasma gas remains inside the quartz tube (510) for a long time, and there is a risk that the quartz tube (510) will deform or melt.

[0048] According to one embodiment of the present invention, the swirl device (400) prevents movement of the quartz tube (510) by fixing the quartz tube (510) surrounding the swirl device (400) at three locations with high-temperature plastic fixing pins (460), and at the same time, by removing the fixing support ledge that had many problems in conventional quartz tubes (510), it is easy to disassemble and assemble, thereby shortening maintenance time and making it easy to replace the swirl device according to changes in the capacity of the microwave plasma system, so it can greatly contribute to the commercialization of the microwave plasma system.

[0049] In one embodiment of the present invention, the swirl device (400) can replace the quartz tube (510) surrounding the swirl device (400) with a tube made of a material through which microwaves can pass, such as a ceramic tube.

[0050] A swirl device (400) according to one embodiment of the present invention is provided with an ignition hole (470) on the inside for igniting a torch, and when the ignition hole (470) is not in use, the entrance of the ignition hole (470) is blocked to prevent air from entering.

[0052] [ Microwave plasma generation in a torch ]

[0053] A torch (500) according to one embodiment of the present invention is surrounded by a quartz tube (510), and while swirl gas (plasma generating gas) produced in a swirl device (400) flows into the quartz tube (510) of the torch (500) while swirling, microwaves (41) generated from a microwave generator (Microwave Generator: 10) pass through the quartz tube (510) and are irradiated onto the swirl gas (450: plasma generating gas) flowing into the quartz tube (510), thereby generating a plasma of about 5,000°C.

[0054] In the stage where plasma is generated, nitrogen (N2) constituting the plasma generating gas is an atom (2N) having radicals. R It is separated into ), and hydrogen (H2) is an atom (2H) having a radical. R It is separated into ), and methane (CH4), the main component of natural gas, is separated into atoms, carbon (C), and hydrogen atoms (4H) containing radicals. R It is converted into ) and becomes high-temperature plasma.

[0055] Microwaves (41) are generated from a microwave generator (10), and after their impedance is stabilized by passing through a circulator (20) and a tuner (30), they are compressed through a tapped wave guide (40) in which the path is gradually narrowed toward the exit and irradiated onto swirl gas (450: plasma generating gas) flowing into a quartz tube (510).

[0057] [ Natural gas cracking in the pre-reactor and reactor ]

[0058] The pre-reactor (600) and the reactor (700) use the high energy of the high-temperature gas in a plasma state generated from the torch (500) to thermally decompose natural gas as shown in the reaction equation below.

[0060] [Equation 1]

[0061] CH4 → C + 2H2△H = 75.6KJ / Mol

[0063] FIG. 6 is a schematic diagram showing the connection structure of a pre-reactor (600) and a reactor (700) according to one embodiment of the present invention, and is a cross-sectional view, and FIG. 7 is a longitudinal section.

[0064] Figure 6 shows four pre-reactors (600) connected to a reactor (700).

[0065] According to one embodiment of the present invention, the gas flow path of the pre-reactor (600) is directly connected to the torch (500), so that the plasma flame (710) of the torch (500) is sprayed into the reactor (700) together with the reaction gas of the pre-reactor (600), as shown in FIG. 6.

[0066] According to the process diagrams of FIGS. 1 and 2, a pre-reactor (600) according to one embodiment of the present invention first decomposes natural gas by contacting and reacting high-temperature gas in a plasma state generated from a torch (500) with natural gas preheated in a heat recovery facility (300), and the natural gas first decomposed in the pre-reactor (600) is secondarily decomposed in a subsequent reactor (700).

[0067] When plasma is generated in the torch (500), electrons detach from the molecules and the temperature rises rapidly (4,000 to 5,000°C). Since the temperature of such highly active plasma decreases when it is stabilized by atomic bonding with atoms of the same type or different types, a pre-reactor (600) according to one embodiment of the present invention is provided to carry out more decomposition reactions in an activated state before the plasma is stabilized.

[0068] The pre-reactor (600) contacts the plasma, which is supplied directly from the torch (500) and in a state where electron movement is most active, with natural gas supplied through a nozzle after being preheated in the heat recovery facility (300), thereby ensuring that sufficient contact between the plasma and the natural gas is maintained in an active state before the plasma is stabilized.

[0069] The pre-reactor (600) efficiently decomposes natural gas by simultaneously carrying out a plasma reaction that decomposes natural gas using the high activity of the plasma and a thermal decomposition reaction that decomposes natural gas using the high temperature (4,000~5,000℃) of the plasma.

[0070] In the process of introducing the gas discharged after primary decomposition of natural gas in a pre-reactor (600) into a reactor (700) together with a plasma flame (710), the discharge gas and the plasma flame (710) are introduced in a diagonal direction of 15 to 45° toward the inner wall of the reactor (700) and swirled to concentrate the temperature in the center of the reactor (700), thereby forming a fire ball (720) in the center and reacting the unreacted natural gas once more, so as to further increase the decomposition rate of the natural gas.

[0071] A reactor (700) according to one embodiment of the present invention also serves as a cyclone reactor by allowing the reaction gas to swirl inside the reactor (700) and discharging the heavy carbon among the carbons generated during the decomposition of natural gas to the bottom.

[0073] [ Separation of hydrogen and carbon and production of high-purity clean hydrogen ]

[0074] The thermal energy of the decomposition gas discharged through the reactor (700) is recovered by the heat recovery facility (300) to preheat the natural gas (100) for raw materials, and then the exhaust gas is cooled to 40~60℃ in the cooler 1 (900), and carbon in the exhaust gas is separated by the microfilter (1000) and transferred to the silo (2000).

[0075] The carbon-separated gas is passed through a HEPA filter (1100) to filter out fine carbon once more, then compressed to about 9 Bar through a compressor (1200), cooled to 40~50°C in a cooler 2 (1300), and then fed into a pressure circulating gas separator (PSA: 1400) to produce high-purity clean hydrogen (99.99%).

[0076] The off gas produced after purifying hydrogen consists of nitrogen, unreacted natural gas, and residual hydrogen. By recirculating it to a swirler (400) with a blower for reuse, the decomposition rate of natural gas can be increased and the amount of nitrogen used can be minimized.

[0078] [ Applications of carbon ]

[0079] Carbon stored in a silo (2000) can be compacted through a carbon compactor (3000) and separated through a carbon separator (4000), then packed with a packing machine (5000) for sale or sold in bulk containers.

[0080] The carbon produced according to one embodiment of the present invention has a nano (nm) particle size and is of excellent quality, making it suitable for use in tire reinforcing agents, inks, batteries, etc. Additionally, since carbon nanotubes (CNT) can be produced when a catalyst is used, the carbon can be sold as a byproduct to minimize carbon dioxide (CO2) emissions while lowering the cost of hydrogen production.

[0081] Although the technical concept of the present invention has been described above together with the accompanying drawings, this is merely an illustrative explanation of preferred embodiments of the present invention, and the scope of protection of the present invention is not limited to the description and expression of the embodiments. Furthermore, it should be noted that obvious changes or substitutions to the technical configuration of the present invention within the technical field to which the present invention belongs cannot limit the scope of protection of the present invention. Explanation of the symbols

[0082] 10 : Microwave Generator 20 : Circulator 30 : Tuner 40 : Taped Wave Guide 41 : Microwave 100 : Natural Gas 200 : Gas Pre-treatment System 300 : Gas Preheater 400 : Swirler 410 : Gas Inlet 420 : Gas Outlet 430 : Spiral Groove 440 : External Protection Case 450 : Swirl Gas 460 : Fixing Pin 470 : Ignition Hole 500 ; Torch 510 : Quartz Tube 600 ; Pre-reactor 700 ; Reactor 710 : Plasma Flame 720 : Fire Ball 900 ; Cooler 1(Cooler 1) 1000 ; Micro Filter 1100 ; HEPA Filter 1200 ; Gas Compressor 1300 ; Cooler 2 1400 ; Pressure Swing Absorber (PSA) 2000 ; Silo} 3000 ; Carbon Compactor 4000 ; Carbon Separator 5000 ; Packing Machine (Packing M / C)

Claims

Claim 1 A swirl device (400) that supplies plasma generating gas to a torch (500) while swirling it; and a torch (500) that generates plasma by irradiating the swirling plasma generating gas with microwaves; A clean hydrogen and nanocarbon manufacturing system using microwave plasma comprising a reactor (700) that decomposes natural gas with plasma generated from a torch (500), wherein the swirl device (400) is provided with one inlet (410) formed in the center of the front end, a plurality of discharge ports (420) formed inside, and a spiral groove (430) formed on the outer circumference, and when plasma generating gas is injected into the one inlet (410) formed in the center of the front end of the swirl device (400) and discharged through the plurality of discharge ports (430) formed inside, the plasma generating gas is separated into multiple branches and introduced into the torch (500) while swirling along the spiral groove (430) formed on the outer circumference of the swirl device (400), and the contact time between the plasma generating gas and the microwave in the torch (500) is controlled by varying the number of discharge ports (420) of the swirl device (400). Clean hydrogen and nanocarbon production system using plasma. Claim 2 In claim 1, the plasma generating gas is a clean hydrogen and nanocarbon manufacturing system using microwave plasma consisting of nitrogen and natural gas. Claim 3 delete Claim 4 A clean hydrogen and nanocarbon manufacturing system using microwave plasma according to claim 1, further comprising a pre-reactor (600) that decomposes natural gas by utilizing the high activity of plasma supplied directly from a torch (500) and the high temperature of the plasma in the preceding stage of the reactor (700). Claim 5 A method for producing clean hydrogen and nanocarbon using microwave plasma, comprising the steps of: supplying a plasma generating gas to a torch (500) while swirling it through a swirler (400); generating microwave plasma by irradiating the plasma generating gas with microwaves at the torch (500); and decomposing natural gas with the microwave plasma in a pre-reactor (600) and a reactor (700), wherein the step of supplying the plasma generating gas to a torch (500) while swirling it through a swirler (400) comprises the step of injecting the plasma generating gas into a single inlet (410) formed in the center of the front end of the swirler (400) and discharging it through a plurality of discharge ports (430) formed inside, thereby separating the plasma generating gas into multiple branches and introducing it into the torch (500) while swirling along a spiral groove (430) formed on the outer circumference of the swirler (400). Nanocarbon manufacturing method. Claim 6 In claim 5, the step of supplying the plasma generating gas to the torch (500) while swirling it with the swirler (400) includes the step of varying the number of discharge ports (430) of the swirler (400) so as to control the contact time between the plasma generating gas and the microwave in the torch (500), in a method for producing clean hydrogen and nanocarbon using microwave plasma. Claim 7 In claim 5, the step of decomposing natural gas in the pre-reactor (600) comprises the step of contacting natural gas, which is preheated in a heat recovery facility (300) and supplied to the pre-reactor (600) through a nozzle, with a plasma in which electron movement is most active and which is supplied directly from a torch (500) to the pre-reactor (600). This describes a method for producing clean hydrogen and nanocarbon using microwave plasma. Claim 8 In claim 5, the step of decomposing natural gas in the reactor (700) comprises the step of introducing the gas discharged after primary decomposition in the pre-reactor (600) into the reactor (700) together with the plasma flame (710), and swirling the discharged gas and the plasma flame (710) toward the inner wall of the reactor (700) to concentrate the temperature in the center of the reactor (700) and react the unreacted natural gas once more. Claim 9 A swirl device (400) for a microwave plasma system that supplies plasma generating gas to a torch (500) while swirling it, wherein the swirl device comprises one inlet (410) formed in the center of the front end, a plurality of discharge ports (420) formed inside, and a spiral groove (430) formed on the outer circumference, wherein when plasma generating gas is injected into the one inlet (410) formed in the center of the front end of the swirl device (400) and discharged through the plurality of discharge ports (430) formed inside, the plasma generating gas is separated into multiple branches and swirls along the spiral groove (430) formed on the outer circumference of the swirl device (400) while being introduced into the torch (500). Claim 10 In claim 9, a swirl device for a microwave plasma system having the function of adjusting the contact time between the plasma generating gas and the microwave in the torch (500) by varying the number of the discharge ports (420).

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