Device and method for producing hydrogen by cracking ammonia through microwave resonance plasma torch

Abstract

The invention provides a device for producing hydrogen by cracking ammonia through a microwave resonance plasma torch, and the device comprises a microwave unit which is suitable for generating microwaves; and the reaction unit is connected with the microwave unit. The reaction unit includes a resonant torch. The resonance torch comprises a shell, the shell is provided with a closed end and an open end, a resonant cavity is formed between the closed end and the open end, the outer wall of the shell is provided with a gas inlet communicated with the resonant cavity, and the gas inlet is suitable for being communicated with an external ammonia gas source; and the central electrode is arranged in the resonant cavity in a penetrating manner. Microwaves are fed into the resonant cavity from the closed end to generate microwave resonance, and a plasma area is formed around the tip, close to the open end, of the central electrode, so that ammonia gas flowing in from the gas inlet is subjected to a cracking reaction when passing through the plasma area, and cracked gas containing hydrogen is generated. The invention further provides a method for producing hydrogen by cracking ammonia through the microwave resonance plasma torch.

Description

Technical Field

[0001] The present disclosure relates to the field of zero-carbon fuel and fuel reforming, and in particular to a method and device for producing hydrogen by cracking ammonia using a microwave resonant plasma torch. Background Art

[0002] Ammonia (NH3) is an excellent carrier of hydrogen, with advantages such as high hydrogen density and safe storage and transportation. The NH bond of ammonia molecules has a high binding energy, and the ammonia cracking reaction requires a high energy consumption, so the energy consumption of the usual ammonia cracking hydrogen production system is high. In recent years, the development of efficient and energy-saving ammonia cracking hydrogen production technology has become an international research hotspot. At present, ammonia cracking hydrogen production methods can be divided into two categories: thermal and non-thermal. Thermal decomposition is the most widely used traditional method, which usually requires a high-temperature heat source (above 700°C) combined with a catalyst to achieve a cracking rate of more than 90%, but due to the heat loss of the high-temperature heat source, the thermal efficiency of the system is often not high. In addition to relying on catalysts and being too large in size, due to the thermal inertia of the heating system, the system has a long hydrogen production response time, that is, poor dynamic responsiveness, and it is difficult to adapt to the requirements of transient operating conditions of mobile source power devices such as internal combustion engines for hydrogen supply. If the engine exhaust waste heat is used to crack ammonia, the operating temperature of the cracker and the operating power of the internal combustion engine are highly coupled. The exhaust temperature of the engine is too low under cold start and low load conditions, which will significantly reduce the hydrogen production efficiency of the cracker. In terms of non-thermal decomposition, common methods include electrolysis and photocatalysis. These methods usually also require catalysts, and the cracking rate and feed gas flow rate are usually not high, which is still far from practical application. In short, whether it is thermal or non-thermal ammonia decomposition to produce hydrogen, there are often problems such as long system hydrogen production response time and large volume, which makes it difficult to apply to mobile power source power devices such as internal combustion engines. Summary of the invention

[0003] In view of this, the present disclosure provides a device and method for producing hydrogen by cracking ammonia using a microwave resonant plasma torch.

[0004] In one aspect of the present disclosure, a device for producing hydrogen by cracking ammonia with a microwave resonant plasma torch is provided, comprising: a microwave unit, which is suitable for generating microwaves; a reaction unit, which is connected to the microwave unit, and the reaction unit comprises a resonant torch, and the resonant torch comprises: a shell, which has a closed end and an open end, and a resonant cavity is formed between the closed end and the open end, and the outer wall of the shell is provided with an air inlet connected to the resonant cavity, and the air inlet is suitable for being connected to an external ammonia gas source; a central electrode, which is inserted into the resonant cavity; microwaves are fed into the resonant cavity from the closed end to generate microwave resonance, and a plasma region is formed around the tip of the central electrode close to the open end, so that the ammonia gas flowing in from the air inlet undergoes a cracking reaction when passing through the plasma region to generate cracked gas containing hydrogen.

[0005] According to an embodiment of the present disclosure, the length of the center electrode is configured to be one quarter of the wavelength of the microwave.

[0006] According to an embodiment of the present disclosure, the reaction unit further comprises a tubular member, one end of which is connected to the open end of the shell so as to output the cracked gas from the other end of the tubular member.

[0007] According to an embodiment of the present disclosure, the tip of the center electrode extends into the tubular member, and the inner diameter of the tubular member matches the diameter of the plasma region.

[0008] According to an embodiment of the present disclosure, there are multiple air inlets, and the multiple air inlets are evenly distributed on the outer wall of the shell at the same height.

[0009] According to an embodiment of the present disclosure, the resonant torch also includes a radio frequency connector, which is detachably connected to the closed end of the shell and connected to the center electrode, and is suitable for feeding the microwaves emitted by the microwave unit into the resonant cavity; a magnetic coupling component is arranged in the resonant cavity, one end of the magnetic coupling component is connected to the center electrode, and the other end of the magnetic coupling component is connected to the inner wall of the radio frequency connector.

[0010] According to an embodiment of the present disclosure, the radio frequency connector and the center electrode are constructed into an integrated structure.

[0011] According to an embodiment of the present disclosure, it further includes: a detection unit, which is arranged downstream of the reaction unit, and the detection unit is suitable for receiving the cracking gas from the reaction unit and detecting the concentration of residual ammonia in the cracking gas.

[0012] According to an embodiment of the present disclosure, it also includes: a dual directional coupler, which is arranged between the microwave unit and the reaction unit, and the dual directional coupler is suitable for detecting the microwave power output by the microwave unit to the reaction unit.

[0013] Another aspect of the present disclosure provides a method for producing hydrogen by cracking ammonia using a microwave resonant plasma torch, comprising: feeding microwaves into a resonant cavity so that the microwaves resonate in the resonant cavity and form a plasma region around the tip of a central electrode; inputting ammonia into the resonant cavity so that a cracking reaction occurs when the ammonia flows through the plasma region to generate a cracked gas containing hydrogen; detecting the concentration of residual ammonia in the cracked gas; and adjusting the intake amount of ammonia and / or the power of the microwave based on the concentration of the residual ammonia to obtain a cracked gas with a target concentration of hydrogen.

[0014] According to the device for producing hydrogen by cracking ammonia with a microwave resonant plasma torch provided by the present invention, microwave resonance occurs in the resonant cavity through the resonant cavity and the central electrode, and high-energy plasma is formed at the tip of the central electrode. A large number of charged particles with energy inside the plasma collide and react with other particles, providing a highly active atmosphere for the chemical reaction, causing the NH bonds in the ammonia molecules to break, achieving efficient ammonia cracking, producing a large amount of hydrogen and nitrogen, and having a fast response capability. At the same time, the hydrogen production device does not require huge high-temperature heat source equipment, is compact in size, and is easy to install, and is suitable for mobile source power devices such as automobiles, ships and aircraft. In addition, the hydrogen production device mainly relies on the chemical reaction activity of high-energy plasma, thereby reducing dependence on catalysts. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The above and other objects, features and advantages of the present disclosure will become more apparent through the following description of the embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0016] Figure 1 The overall structural diagram of the device for producing hydrogen by cracking ammonia using a microwave resonant plasma torch according to an embodiment of the present disclosure is schematically shown;

[0017] Figure 2 The schematic diagram of the structure of the reaction unit according to the embodiment of the present disclosure is shown;

[0018] Figure 3 The overall structural diagram of a device for producing hydrogen by cracking ammonia using a microwave resonant plasma torch according to another embodiment of the present disclosure is schematically shown;

[0019] Figure 4 A flow chart of a method for producing hydrogen by cracking ammonia using a microwave resonant plasma torch according to an embodiment of the present disclosure is schematically shown.

[0020] Reference numerals

[0021] 1. Microwave unit;

[0022] 2. Reaction unit;

[0023] 21. Resonance torch;

[0024] 211. Shell;

[0025] 212. Resonant cavity;

[0026] 213, center electrode;

[0027] 214. RF connector;

[0028] 215. Magnetic coupling parts;

[0029] 216, air intake;

[0030] 22. Tubular parts;

[0031] 23. Fixed flange;

[0032] 24. Tighten the bolts;

[0033] 3. Dual directional coupler;

[0034] 31. Microwave input port;

[0035] 32. Microwave output port;

[0036] 33. Forward power sampling port;

[0037] 34. Reverse power sampling port;

[0038] 35. Forward microwave power meter;

[0039] 36. Reverse microwave power meter;

[0040] 4. Detection unit. DETAILED DESCRIPTION

[0041] In order to make the objectives, technical solutions and advantages of the present disclosure more clearly understood, the present disclosure is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0042] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The terms "comprise", "include", etc. used herein indicate the existence of features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0043] All terms used herein, including technical and scientific terms, have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification, and should not be interpreted in an idealized or overly rigid manner.

[0044] When using expressions such as "at least one of A, B, and C, etc.", it should generally be interpreted as the meaning of the expression generally understood by those skilled in the art. For example, "a system having at least one of A, B, and C" should include but not be limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc. When using expressions such as "at least one of A, B, or C, etc.", it should generally be interpreted as the meaning of the expression generally understood by those skilled in the art. For example, "a system having at least one of A, B, or C" should include but not be limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.

[0045] It should also be noted that the directional terms mentioned in the embodiments, such as "upper", "lower", "front", "back", "left", "right", etc., are only reference directions of the drawings and are not intended to limit the scope of protection of the present disclosure. Throughout the drawings, the same elements are represented by the same or similar reference numerals. Conventional structures or configurations will be omitted when they may cause confusion in the understanding of the present disclosure.

[0046] Figure 1 The overall structural diagram of the hydrogen production device according to an embodiment of the present disclosure is schematically shown.

[0047] According to the device for producing hydrogen by cracking ammonia using a microwave resonant plasma torch provided in the present disclosure, Figure 1 As shown, the hydrogen production device includes a microwave unit 1 and a reaction unit 2. The microwave unit 1 is suitable for generating microwaves. The reaction unit 2 is connected to the microwave unit 1, and the reaction unit 2 includes a resonant torch 21. The resonant torch 21 includes a shell 211 and a central electrode 213. The shell 211 has a closed end and an open end, and a resonant cavity 212 is formed between the closed end and the open end. The outer wall of the shell 211 is provided with an air inlet connected to the resonant cavity 212, and the air inlet is suitable for being connected to an external ammonia gas source. The central electrode 213 is arranged in the resonant cavity 212. Microwaves are fed from the closed end into the resonant cavity 212 to cause microwave resonance, and a plasma region is formed around the tip of the central electrode 213 near the open end, so that the ammonia gas flowing in from the air inlet undergoes a cracking reaction when passing through the plasma region to generate cracked gas containing hydrogen.

[0048] The microwave unit 1 may include a microwave source and a transmission device. The microwave source is used to generate microwaves. A magnetron may be used as the microwave source to significantly reduce the cost of the hydrogen production device. The transmission device may be, for example, a waveguide or a radio frequency cable to transmit the generated microwave energy to the reaction unit 2. In addition, in order to adapt to different reaction requirements of the reaction unit 2, the microwave unit 1 may also be provided with a power control device to adjust the output power of the microwave source.

[0049] The shell 211 of the resonant torch 21 can be made of a material that is resistant to high temperatures and has good electrical conductivity, such as copper. The shell 211 includes but is not limited to being constructed in a tubular shape or a rectangular shape with a cavity, one end of the shell 211 is closed as a closed end, and the other end is provided with an opening as an open end, and a semi-closed resonant cavity is formed between the closed end and the open end. The central electrode 213 is arranged on the central axis of the resonant cavity. In this case, the shell 211 serves as an outer conductor and the central electrode serves as an inner conductor, so that the microwave resonates in the resonant cavity when microwaves are fed in.

[0050] When microwaves matching the natural frequency of the resonant cavity 212 are fed into the resonant cavity 212, the microwave energy will form a standing wave inside the resonant cavity 212, that is, an electromagnetic wave whose amplitude remains unchanged during propagation and whose phase changes periodically with the spatial position. In the standing wave, the electric field and magnetic field intensity reach the maximum at a specific position, forming a high-intensity electric field or magnetic field region. Therefore, the central electrode 213 is inserted into the resonant cavity 212 so that the tip of the central electrode 213 is in the area where the electric field intensity reaches the maximum position. The tip structure of the central electrode 213 can be used to make the electric field energy highly concentrated around the tip of the central electrode 213, forming a high-intensity electric field region. The high-intensity electric field is used to ionize the surrounding gas molecules, generating a plasma composed of a large number of charged particles and neutral particles, thereby forming a plasma region around the tip of the central electrode 213.

[0051] Since there are a large number of charged particles with energy inside the plasma, they will collide and react with other particles, creating a highly active chemical reaction environment. When ammonia is transported into the plasma area, the high-energy electrons in the plasma can effectively collide with the ammonia molecules, breaking the NH bonds inside them, thereby causing the ammonia molecules to decompose into nitrogen and hydrogen.

[0052] In such an embodiment, microwaves resonate in the resonant cavity through the resonant cavity 212 and the central electrode 213, and high-energy plasma is formed at the tip of the central electrode. The highly active atmosphere inside the plasma can effectively break the NH bonds in the ammonia molecules, thereby achieving efficient ammonia cracking, producing a large amount of hydrogen and nitrogen, and having a fast response capability. At the same time, the hydrogen production device does not require large high-temperature heat source equipment, is compact and easy to install, and is suitable for mobile source power devices such as automobiles, ships and aircraft. In addition, the hydrogen production device mainly relies on the chemical reaction activity of high-energy plasma, thereby reducing dependence on catalysts.

[0053] According to an embodiment of the present disclosure, the length of the center electrode 213 is configured to be one quarter of the wavelength of microwaves.

[0054] Specifically, a central electrode 213 with a length of one quarter of the microwave wavelength is inserted into the resonant cavity 212 to form a quarter-wavelength resonant cavity. One end of the central electrode with a length of one quarter of the wavelength is connected to the outer shell, and the other end (i.e., the tip) is open. At this time, the electric field intensity at the tip of the central electrode is extremely high, which can concentrate energy to directly act on the gas molecules, thereby improving the ionization efficiency.

[0055] The present disclosure is not limited thereto. In some embodiments, the length of the central electrode 213 can also be configured to be half the wavelength of the microwave. The half-wavelength central electrode 213 is inserted into the resonant cavity to form a half-wavelength resonant cavity. At this time, the two ends of the central electrode 213 are located at the antinode position of the standing wave (the area with the strongest electric field), and the electric field intensity at the two ends of the central electrode is the largest, so that a high electric field area is formed at the tip of the central electrode, which effectively accelerates electrons and promotes the ionization of ammonia, thereby efficiently generating plasma.

[0056] In some embodiments, the resonant cavity 212 may be changed to a capacitor-loaded microwave resonant cavity, which may also generate plasma to decompose ammonia to produce hydrogen.

[0057] Figure 2 The structural diagram of the reaction unit 2 according to an embodiment of the present disclosure is schematically shown.

[0058] According to the embodiments of the present disclosure, Figure 2 As shown, the reaction unit 2 further includes a tubular member 22 , one end of which is connected to the open end of the shell 211 so that the cracked gas can be output from the other end of the tubular member 22 .

[0059] Specifically, the open end of the shell 211 is provided with an opening, and one end of the tubular member 22 can be connected to the opening, so that the resonant cavity 212 and the tubular member 22 are connected, thereby, the tubular member 22 can be used to output the cracking gas from the other end of the tubular member 22.

[0060] In some embodiments, Figure 2 As shown, a fixing flange 23 may be sleeved on the outside of the tubular member 22 , and the housing 211 and the fixing flange 23 may be fixed by fastening bolts 24 , so that the tubular member 22 and the resonant cavity 212 are closely connected.

[0061] Preferably, the tubular member 22 may be a quartz tube having a quartz channel cavity in the quartz tube, through which the cracked gas flows out. The present disclosure is not limited thereto, and the tubular member 22 may also be made of high temperature resistant plastic or glass.

[0062] According to the embodiments of the present disclosure, Figure 2As shown, the tip of the central electrode 213 extends into the tubular member 22, and the inner diameter of the tubular member 22 matches the diameter of the plasma region.

[0063] Specifically, the tip of the center electrode 213 may be substantially flush with the open end of the shell 211, and at least a portion of the tubular member 22 is embedded in the resonant cavity 212, so that the tip of the center electrode 213 extends into the tubular member 22. The present disclosure is not limited thereto, and the center electrode 213 may also be slightly higher or slightly lower than the open end of the shell 211, as long as the tip of the center electrode 213 extends into the tubular member 22.

[0064] Preferably, the inner diameter of the tubular member 22 is consistent with the maximum outer diameter of the plasma region.

[0065] In such an embodiment, when ammonia flows from the air inlet to the open end, it will flow into the tubular member 22, and the ammonia gas flow will be constrained by the inner wall of the tubular member 22. Since the tip of the central electrode 213 is located in the tubular member 22, and the inner diameter of the tubular member 22 matches the outer diameter of the shell 211, it can be ensured that when ammonia molecules flow through the plasma region, they collide with the electrons in the plasma as much as possible to cause cracking reactions, thereby improving the cracking efficiency of the ammonia.

[0066] According to the embodiments of the present disclosure, Figure 2 As shown, the outer wall of the shell 211 may be provided with a plurality of air inlets 216 , and the plurality of air inlets 216 are evenly distributed on the outer wall of the shell 211 at the same height.

[0067] Specifically, the air inlet 216 can be disposed on the outer wall of the housing 211 near the closed end, and form an air inlet channel with the resonant cavity 212, and each air inlet 216 is connected to an external ammonia gas source to input ammonia into the resonant cavity 212. When inputting ammonia into the resonant cavity 212, each air inlet 216 can input the same air flow into the resonant cavity 212 to form a stable ammonia gas flow in the resonant cavity 212.

[0068] In some embodiments, Figure 2 As shown, the air inlet 216 can be set to two, and the two air inlets 216 can be symmetrically arranged on the outer wall of the shell 211. In some embodiments, the air inlet 216 can also be set to three or four, and the three or four air inlets 216 are evenly distributed on the outer wall of the shell 211 at the same height.

[0069] In such an embodiment, multiple evenly distributed gas inlets 216 can ensure that the gas is evenly distributed inside the torch tube to form a stable gas flow field, which helps to reduce turbulence and vortex inside the housing 211, so that the plasma will not be disturbed by the unstable ammonia gas flow, thereby improving the stability of the plasma.

[0070] According to the embodiments of the present disclosure, Figure 2 As shown, the resonant torch 21 further includes a radio frequency connector 214 , which is detachably connected to the closed end of the shell 211 and connected to the central electrode 213 . The radio frequency connector 214 is suitable for feeding the microwaves emitted by the microwave unit 1 into the resonant cavity 212 .

[0071] In some embodiments, the RF connector 214 is pluggably connected to the closed end of the housing 211. Specifically, the RF connector 214 is provided with an interface or plug, and correspondingly, the closed end of the housing 211 is provided with a matching interface or socket to achieve pluggable connection of the RF connector 214.

[0072] The RF connector 214 includes a shell, an inner conductor and an insulator. The inner conductor is the main channel for transmitting RF signals. The inner conductor can be made of a metal material with good electrical conductivity, such as copper or copper alloy, to ensure low-loss transmission of the signal. The shell surrounds the inner conductor and is used to shield electromagnetic interference and ground. The shell can also be made of a metal material with good electrical conductivity and mechanical strength, which can effectively prevent the influence of external electromagnetic interference on the signal. The insulator is located between the inner conductor and the shell to isolate the two and prevent signal short circuit and interference. The insulator material is usually selected from materials with stable dielectric constant and good temperature resistance to ensure the reliability of the RF connector 214.

[0073] In such an embodiment, the RF connector 214 serves as a transmission channel between the microwave source and the resonant cavity 212 , and can efficiently and stably transmit the microwave signal into the resonant cavity 212 .

[0074] According to an embodiment of the present disclosure, the RF connector 214 and the central electrode 213 are constructed as an integrated structure.

[0075] Specifically, the central electrode 213 may be constructed into an integrated structure with the inner conductor of the RF connector 214 to reduce the contact resistance and signal reflection at the connection, thereby improving the signal transmission efficiency.

[0076] According to an embodiment of the present disclosure, the resonant torch 21 further includes a magnetic coupling member 215 disposed in the resonant cavity 212 , one end of the magnetic coupling member 215 is connected to the central electrode 213 , and the other end of the magnetic coupling member 215 is connected to the inner wall of the RF connector 214 .

[0077] In some embodiments, one end of the magnetic coupling member 215 is welded to the surface of the center electrode 213 to form a low impedance path, and the other end of the magnetic coupling member 215 is tightly fitted with the metal contact on the inner wall of the RF connector 214 to ensure efficient magnetic field coupling.

[0078] In some embodiments, the magnetic coupling element 215 may be composed of a magnetic core made of a high magnetic permeability material (such as ferrite) and a copper coil wound around it.

[0079] In such an embodiment, the RF power can be efficiently coupled into the resonant cavity 212 to excite the plasma through the magnetic coupling element 215. At the same time, the impedance matching can be achieved by adjusting the degree of magnetic coupling to ensure that the RF energy is transferred to the plasma region to the maximum extent and reduce the reflection loss.

[0080] Figure 3 The overall structural diagram of a device for producing hydrogen by cracking ammonia using a microwave resonant plasma torch according to another embodiment of the present disclosure is schematically shown.

[0081] According to the embodiments of the present disclosure, Figure 3 As shown, in addition to the microwave unit 1 and the reaction unit 2, the hydrogen production device may also be provided with a detection unit 4. The detection unit 4 may be provided downstream of the reaction unit 2. The detection unit 4 is suitable for receiving the cracking gas from the reaction unit 2 and detecting the concentration of residual ammonia in the cracking gas.

[0082] In some embodiments, the detection unit 4 may be connected to the other end of the tubular member 22 in the reaction unit 2. An electrochemical sensor probe may be provided in the detection unit 4, and the concentration of ammonia in the cracked gas may be detected by the electrochemical sensor. Specifically, when the cracked gas passes through the electrochemical sensor, an electrochemical reaction occurs on the surface of the electrochemical sensing electrode, generating a current signal proportional to the residual ammonia concentration, which is converted into a residual ammonia concentration value by an amplifying circuit.

[0083] In such an embodiment, by providing a detection unit 4 in the hydrogen production device to detect the concentration of residual ammonia in the cracked gas downstream of the reaction unit 2, the hydrogen production process can be adjusted and optimized, such as adjusting the ammonia intake or adjusting the microwave power, to improve the hydrogen production efficiency and product quality.

[0084] According to the embodiments of the present disclosure, Figure 3 As shown, in addition to the microwave unit 1, the reaction unit 2 and the detection unit 4, the hydrogen production device also includes a dual directional coupler 3. The dual directional coupler 3 is arranged between the microwave unit 1 and the reaction unit 2, and the dual directional coupler 3 is suitable for detecting the microwave power outputted from the microwave unit 1 to the reaction unit 2.

[0085] Specifically, the dual directional coupler 3 includes a microwave input port 31, a microwave output port 32, a forward power sampling port 33, a reverse power sampling port 34, a forward microwave power meter 35, and a reverse microwave power meter 36. The microwave unit 1 is connected to the microwave input port 31, the microwave output port 32 is connected to the RF connector 214, the forward microwave power meter 35 is used to collect the forward microwave power at the forward power sampling port 33, and the reverse microwave power meter 36 is used to collect the reverse microwave power at the reverse power sampling port 34.

[0086] In some embodiments, microwave components such as RF connectors and dual directional couplers are matched with the impedance of the microwave source. For example, the characteristic impedance of microwave components such as RF connectors and dual directional couplers is 50Ω to reduce reflection loss.

[0087] In such an embodiment, the dual directional coupler 3 can monitor the microwave power outputted from the microwave unit 1 to the reaction unit 2 in real time and accurately, which helps the operator to timely understand the operation status of the microwave unit and ensure that the microwave energy is transmitted to the reaction unit 2 in an expected manner. It can also ensure that the microwave power fluctuates within a set range, thereby maintaining the stability of the reaction conditions and improving the controllability of the hydrogen production process.

[0088] According to the hydrogen production device provided by the present disclosure, the overall device is small in size, easy to carry and install, and mainly relies on the chemical reaction activity of high-energy plasma to efficiently crack ammonia, thereby achieving efficient production of hydrogen and reducing dependence on catalysts.

[0089] The present disclosure also provides a method for producing hydrogen by cracking ammonia using a microwave resonant plasma torch, the method comprising operations S410 to S440.

[0090] In operation S410 , microwaves are fed into the resonant cavity, so that the microwaves resonate in the resonant cavity 212 and form a plasma region around the tip of the central electrode 213 .

[0091] In operation S420, ammonia gas is input into the resonant cavity 212, so that a cracking reaction occurs when the ammonia gas flows through the plasma region to generate cracked gas containing hydrogen.

[0092] In operation S430, the concentration of residual ammonia in the cracked gas is detected.

[0093] In operation S440, based on the concentration of the residual ammonia, the intake amount of ammonia and / or the power of the microwave are adjusted to obtain cracked gas with a target concentration of hydrogen.

[0094] In some embodiments, the microwave unit 1 generates microwaves, and the microwave energy is input into the dual directional coupler 3 through the microwave input port 31, and the forward microwave power and the reverse microwave power obtained by sampling are respectively outputted at the forward power sampling port 33 and the reverse power sampling port 34, and their power values ​​are respectively read by the forward microwave power meter 35 and the reverse microwave power meter 36, and the microwave energy is outputted from the microwave output port 32 of the dual directional coupler 3, and the microwave energy is fed into the microwave resonant cavity 212 through the RF connector 214 and the magnetic coupling member 215, the microwave resonates in the microwave resonant cavity 212, and plasma is formed at the tip of the central electrode 213, ammonia enters the microwave resonant cavity 212 through the gas feeding interface and is restricted by the tubular member 22 near the tip of the central electrode 213, ammonia undergoes a cracking reaction after passing through the plasma region, the cracked product gas enters the detection unit 4 and monitors the residual ammonia concentration, and the power and ammonia flow rate of the microwave unit 1 are regulated according to the residual ammonia concentration to ensure the optimal cracking condition.

[0095] According to the method for producing hydrogen by cracking ammonia using a microwave resonant plasma torch disclosed in the present invention, microwave resonance occurs in the resonant cavity 212, and high-energy plasma is formed at the tip of the central electrode 213, and plasma is used to achieve efficient cracking of ammonia, producing a large amount of hydrogen and nitrogen, with the advantages of fast response speed, high cracking rate, low energy consumption, low cost, small device size, and easy to carry. This method has broad application prospects in the field of hydrogen preparation, especially in scenarios where rapid, efficient, and low-energy hydrogen preparation is required, such as internal combustion engines, fuel cells, and other fields.

[0096] The embodiments of the present disclosure are described above. However, these embodiments are only for the purpose of illustration and are not intended to limit the scope of the present disclosure. Although the embodiments are described above separately, this does not mean that the measures in the various embodiments cannot be used in combination to advantage. The scope of the present disclosure is defined by the attached claims and their equivalents. Without departing from the scope of the present disclosure, those skilled in the art may make various substitutions and modifications, which should all fall within the scope of the present disclosure.

Claims

1. A device for producing hydrogen by cracking ammonia using a microwave resonant plasma torch, characterized in that: include: A microwave unit (1) adapted to generate microwaves; A reaction unit (2) is connected to the microwave unit (1), wherein the reaction unit (2) comprises a resonance torch (21), and the resonance torch (21) comprises: A shell (211) having a closed end and an open end, a resonance cavity (212) being formed between the closed end and the open end, an outer wall of the shell (211) being provided with an air inlet (216) in communication with the resonance cavity (212), the air inlet (216) being suitable for being in communication with an external ammonia gas source; A central electrode (213) is disposed in the resonant cavity (212); The microwaves are fed from the closed end into the resonant cavity (212) to generate microwave resonance, and a plasma region is formed around the tip of the central electrode (213) close to the open end, so that ammonia gas flowing in from the gas inlet (216) undergoes a cracking reaction when passing through the plasma region, generating cracked gas containing hydrogen.

2. The device according to claim 1, characterized in that The length of the central electrode (213) is configured to be one quarter of the wavelength of the microwave.

3. The device according to claim 1, characterized in that The reaction unit (2) further comprises a tubular member (22), one end of the tubular member (22) being connected to the open end of the shell (211) so that the cracked gas can be output from the other end of the tubular member (22).

4. The device according to claim 3, characterized in that The tip of the central electrode (213) extends into the tubular member (22), and the inner diameter of the tubular member (22) matches the diameter of the plasma region.

5. The device according to claim 1, characterized in that The air inlet (216) comprises a plurality of air inlets (216), and the plurality of air inlets (216) are evenly distributed on an outer wall of the shell (211) at the same height.

6. The device according to claim 1, characterized in that The resonant torch (21) further comprises: a radio frequency connector (214), the radio frequency connector (214) being detachably connected to the closed end of the housing (211) and connected to the central electrode, the radio frequency connector (214) being suitable for feeding the microwaves emitted by the microwave unit into the resonant cavity (212); A magnetic coupling component (215) is arranged in the resonant cavity (212), one end of the magnetic coupling component (215) is connected to the central electrode (213), and the other end of the magnetic coupling component (215) is connected to the inner wall of the radio frequency connector (214).

7. The device according to claim 6, characterized in that The radio frequency connector (214) and the central electrode (213) are constructed into an integrated structure.

8. The device according to any one of claims 1 to 7, characterized in that: Also includes: The detection unit (4) is arranged downstream of the reaction unit (2), and the detection unit (4) is suitable for receiving the cracked gas from the reaction unit (2) and detecting the concentration of residual ammonia in the cracked gas.

9. The device according to any one of claims 1 to 7, characterized in that: Also includes: A dual directional coupler (3) is arranged between the microwave unit (1) and the reaction unit (2), and the dual directional coupler (3) is suitable for detecting the microwave power output by the microwave unit (1) to the reaction unit.

10. A method for producing hydrogen by cracking ammonia using a microwave resonant plasma torch based on the device according to any one of claims 1 to 9, characterized in that: include: Feeding microwaves into the resonant cavity (212) so that the microwaves resonate in the resonant cavity (212) and form a plasma region around the tip of the central electrode (213); Inputting ammonia gas into the resonant cavity (212), so that a cracking reaction occurs when the ammonia gas flows through the plasma region, thereby generating cracked gas containing hydrogen; Detecting the concentration of residual ammonia in the cracked gas; Based on the concentration of the residual ammonia, the intake amount of the ammonia and / or the power of the microwave are adjusted to obtain cracked gas with a target concentration of hydrogen.

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