Reaction chamber system for thermal plasma decomposition of sulfur hexafluoride gas

Abstract

Disclosed is a reaction cavity system for thermal plasma decomposition of sulfur hexafluoride gas, wherein the reaction cavity comprises a plasma high-temperature core zone formed at 4000-6000 K, and a gas cyclone is a four-inlet circumferentially uniform three-dimensional spiral flow channel configuration arranged on the reaction cavity, which comprises four circumferentially uniformly distributed inclined gas inlets in a counterclockwise direction, so that a steady-state three-dimensional vortex flow field is formed through the plasma reaction zone within 0.1 ms after the reaction gas is injected, the three-dimensional vortex flow field simultaneously provides an axial velocity component to promote the gas flow, a tangential velocity component to drive the continuous movement of the arc root on the electrode surface, and converges the reaction gas to the plasma high-temperature core zone through the centrifugal effect.

Description

Technical Field

[0001] This invention relates to the field of sulfur hexafluoride gas decomposition technology, and in particular to a reaction chamber system for thermal plasma decomposition of sulfur hexafluoride gas. Background Technology

[0002] SF6 gas possesses extremely high electronegativity and excellent thermal stability, leading to its widespread application in the power industry, particularly in critical facilities such as high-voltage switchgear and gas-insulated substations, where it serves as an ideal insulating medium and arc-quenching material. However, this widespread use conceals significant environmental risks. As a widely used insulating medium in the power industry, SF6 has a global warming potential up to 23,500 times that of carbon dioxide and an atmospheric lifetime of up to 3,200 years, posing a serious threat to climate change.

[0003] Thermal plasma, as the fourth form of matter aggregation, is a reaction medium composed of ionized gas. Its characteristic feature is that the temperature parameters of its components reach dynamic equilibrium through collision processes. This system establishes a multiphase composite system containing free electrons, ions, and neutral particles by converting electrical energy into the internal energy of the working gas. During thermal plasma energy injection, the system temperature can be maintained in the range of 3000-20000K or even higher, prompting the dissociation and ionization of gas molecules to form a collection of particles with high kinetic energy. In the core reaction region, various particles achieve uniformity of temperature parameters through sufficient energy exchange. This quasi-equilibrium state allows the system to be accurately described using classical thermodynamic models. Multiple active components coexist within the thermal plasma system, including but not limited to excited-state molecules, atomic radicals, and charged particles. These components significantly improve chemical reaction efficiency through two mechanisms: providing activation energy and altering reaction pathways. This makes it suitable for processes such as material phase transitions and molecular reconstruction. In the thermal plasma degradation of SF6, thorough mixing of the reactant gases (SF6 and auxiliary active gases) is a crucial prerequisite for achieving efficient degradation. Theoretical research and experimental data show that uneven gas mixing will lead to the following problems: First, insufficient concentration of active gas in local areas will prevent the fluorine free radicals generated by SF6 decomposition from being fully captured, and thus recombine to generate harmful byproducts such as low-fluorine sulfides; Second, uneven flow field distribution will cause problems such as arc instability and local electrode ablation, which will seriously affect the reliability and economy of system operation.

[0004] The information disclosed in the background section is only intended to enhance the understanding of the background of the present invention, and therefore may contain information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0005] To address the shortcomings or defects of the existing technology, a reaction chamber system for the thermal plasma decomposition of sulfur hexafluoride gas is provided. This system enhances the uniformity and stability of the reaction process, optimizes the airflow field, and significantly improves degradation efficiency and system operational reliability.

[0006] The objective of this invention is achieved through the following technical solutions.

[0007] A reaction chamber system for thermal plasma decomposition of sulfur hexafluoride gas includes,

[0008] The reaction chamber includes a high-temperature core region for forming plasma at 4000–6000 K.

[0009] The gas cyclone is a three-dimensional spiral flow channel configuration with four inlets evenly distributed circumferentially on the reaction chamber. It includes four inclined air inlets evenly distributed counterclockwise along the circumferential direction, so that the reaction gas forms a steady three-dimensional vortex flow field that runs through the plasma reaction zone within 0.1 ms after injection. The three-dimensional vortex flow field simultaneously provides an axial velocity component to propel the gas flow, a tangential velocity component to drive the arc root to move continuously on the electrode surface, and converges the reaction gas to the high-temperature core region of the plasma through centrifugal effect.

[0010] In the aforementioned reaction chamber system for thermal plasma decomposition of sulfur hexafluoride gas, the axis of each inlet forms a constant tangential deflection angle of 18°±2° with the radial reference plane of the reaction chamber.

[0011] In the aforementioned reaction chamber system for thermal plasma decomposition of sulfur hexafluoride gas, the gas cyclone includes,

[0012] PTFE base,

[0013] The cathode is located on top of the polytetrafluoroethylene base.

[0014] The anode is spaced relative to the cathode and disposed at the bottom of the polytetrafluoroethylene base.

[0015] A suspended anode, disposed on the polytetrafluoroethylene base and located between the cathode and the anode, and parallel to the anode.

[0016] Air inlet 1 is located between the polytetrafluoroethylene base, the cathode, and the suspended anode. Air inlet 1 has four inclined air inlets evenly distributed in a counterclockwise direction along the circumference.

[0017] Air inlet 2 is located between the polytetrafluoroethylene base and the anode and the suspended anode. Air inlet 2 has four inclined air inlets evenly distributed in a counterclockwise direction along the circumference.

[0018] The air inlet 3 is located on the polytetrafluoroethylene base and on the side of the anode away from the cathode. The air inlet 2 has four inclined air inlets evenly distributed in a counterclockwise direction along the circumference.

[0019] In the reaction chamber system for thermal plasma decomposition of sulfur hexafluoride gas, the axial distance between inlet 1 and inlet 2 is less than the axial distance between inlet 2 and inlet 3.

[0020] In the aforementioned reaction chamber system for thermal plasma decomposition of sulfur hexafluoride gas, the gas cyclone has a plasma channel with a diameter of 8 mm, the inlet diameter of the reaction chamber is 120 mm, and the high-temperature gas expands in volume by 225 times through adiabatic expansion, forming a controllable cooling rate of 10²–10³ K / s.

[0021] In the reaction chamber system for thermal plasma decomposition of sulfur hexafluoride gas, the tangential velocity component drives the arc root to move continuously along the electrode surface at a predetermined frequency, thereby reducing the peak temperature of the electrode surface by at least 300K.

[0022] The reaction chamber system for thermal plasma decomposition of sulfur hexafluoride gas further includes:

[0023] The main sealing system uses a fluororubber double-lip self-tightening sealing ring with a temperature resistance of ≥500℃.

[0024] The mechanical seal structure includes eight high-strength alloy bolts equidistantly distributed along the circumference of the cavity flange, which are preloaded with a preload of 25±2 N·m by a hydraulic torque system.

[0025] The gas leak monitoring unit is modularly arranged on the outside of the cavity door sealing interface, with a response time of ≤0.5 seconds.

[0026] In the aforementioned reaction chamber system for thermal plasma decomposition of sulfur hexafluoride gas, the gas leakage monitoring unit performs point detection based on the initial enrichment effect of the leaking gas at the reaction chamber door. When the detected concentration is ≥20ppm, an audible and visual alarm is triggered, and when it is ≥50ppm, an emergency shutdown is initiated.

[0027] In the reaction chamber system for thermal plasma decomposition of sulfur hexafluoride gas, the reaction gases include SF6, H2 and Ar, which are instantaneously mixed through the three-dimensional spiral flow channel configuration of the gas cyclone, with a mixing uniformity fluctuation of ≤±5%.

[0028] In the aforementioned reaction chamber system for thermal plasma decomposition of sulfur hexafluoride gas, the outer wall of the reaction chamber is equipped with a jacketed water cooling system.

[0029] Compared with the prior art, the beneficial effects of this invention are as follows:

[0030] This invention achieves a significant improvement in SF6 gas treatment efficiency and operational stability through the synergy of hydrocyclone structure optimization, staged reaction chamber design, and a sealing monitoring system. Its core advantages are: extending gas residence time through a three-dimensional vortex field, increasing the SF6 degradation rate to over 99% and reducing by-product generation by 40%; dynamic airflow control extending electrode life by 3-5 times and significantly shortening system maintenance cycles; a modular leak monitoring system enabling rapid response within 0.5 seconds and constructing a multi-layered safety protection system; and adaptability to different gas ratios and flow rates, providing a standardized solution for SF6 treatment in the power industry. Therefore, this invention combines high efficiency, reliability, and environmental friendliness, possessing significant engineering application value.

[0031] The description provided is merely an overview of the technical solution of this invention. In order to make the technical means of this invention clearer and more understandable, so that those skilled in the art can implement it according to the contents of the specification, and to make the described and other objects, features and advantages of this invention more obvious and understandable, specific embodiments of this invention are described below. Attached Figure Description

[0032] Various other advantages and benefits of the present invention will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. It is obvious that the drawings described below are merely some embodiments of the invention, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort. Furthermore, the same reference numerals denote the same parts throughout the drawings.

[0033] In the attached diagram:

[0034] Fig. 1 This is a schematic diagram of the structure of the gas cyclone separator provided in an embodiment of the present invention;

[0035] Fig. 2 This is a schematic diagram of the system structure provided in an embodiment of the present invention.

[0036] The present invention will be further explained below with reference to the accompanying drawings and embodiments. Detailed Implementation

[0037] Specific embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While specific embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the invention and to fully convey the scope of the invention to those skilled in the art.

[0038] It should be noted that certain terms are used in the specification and claims to refer to specific components. Those skilled in the art will understand that different terms may be used to refer to the same component. This specification and claims do not distinguish components based on differences in terminology, but rather on differences in function. The terms "comprising" or "including" used throughout the specification and claims are open-ended and should be interpreted as "comprising but not limited to." The following descriptions are preferred embodiments for carrying out the invention; however, these descriptions are for the purpose of understanding the general principles of the specification and are not intended to limit the scope of the invention. The scope of protection of this invention is determined by the appended claims.

[0039] To facilitate understanding of the embodiments of the present invention, the following will provide further explanation and description with reference to the accompanying drawings and several specific embodiments, and the accompanying drawings do not constitute a limitation on the embodiments of the present invention.

[0040] To better understand, such as Figs. 1-2 As shown, a reaction chamber system for thermal plasma decomposition of sulfur hexafluoride gas includes,

[0041] The reaction chamber includes a high-temperature core region for forming plasma at 4000–6000 K.

[0042] The gas cyclone is a three-dimensional spiral flow channel configuration with four inlets evenly distributed circumferentially on the reaction chamber. It includes four inclined air inlets evenly distributed counterclockwise along the circumferential direction, so that the reaction gas forms a steady three-dimensional vortex flow field that runs through the plasma reaction zone within 0.1 ms after injection. The three-dimensional vortex flow field simultaneously provides an axial velocity component to propel the gas flow, a tangential velocity component to drive the arc root to move continuously on the electrode surface, and converges the reaction gas to the high-temperature core region of the plasma through centrifugal effect.

[0043] In a preferred embodiment of the reaction chamber system for thermal plasma decomposition of sulfur hexafluoride gas, the axis of each inlet forms a constant tangential deflection angle of 18°±2° with the radial reference plane of the reaction chamber.

[0044] In a preferred embodiment of the reaction chamber system for thermal plasma decomposition of sulfur hexafluoride gas, the gas cyclone includes,

[0045] PTFE base,

[0046] The cathode is located on top of the polytetrafluoroethylene base.

[0047] The anode is spaced relative to the cathode and disposed at the bottom of the polytetrafluoroethylene base.

[0048] A suspended anode, disposed on the polytetrafluoroethylene base and located between the cathode and the anode, and parallel to the anode.

[0049] Air inlet 1 is located between the polytetrafluoroethylene base, the cathode, and the suspended anode. Air inlet 1 has four inclined air inlets evenly distributed in a counterclockwise direction along the circumference.

[0050] Air inlet 2 is located between the polytetrafluoroethylene base and the anode and the suspended anode. Air inlet 2 has four inclined air inlets evenly distributed in a counterclockwise direction along the circumference.

[0051] The air inlet 3 is located on the polytetrafluoroethylene base and on the side of the anode away from the cathode. The air inlet 2 has four inclined air inlets evenly distributed in a counterclockwise direction along the circumference.

[0052] In a preferred embodiment of the reaction chamber system for thermal plasma decomposition of sulfur hexafluoride gas, the axial distance between inlet 1 and inlet 2 is less than the axial distance between inlet 2 and inlet 3.

[0053] In a preferred embodiment of the reaction chamber system for thermal plasma decomposition of sulfur hexafluoride gas, the gas cyclone has a plasma channel with a diameter of 8 mm, the inlet diameter of the reaction chamber is 120 mm, and the high-temperature gas expands 225 times in volume through adiabatic expansion, forming a controllable cooling rate of 10²–10³ K / s.

[0054] In a preferred embodiment of the reaction chamber system for thermal plasma decomposition of sulfur hexafluoride gas, the tangential velocity component drives the arc root to move continuously along the electrode surface at a predetermined frequency, thereby reducing the peak temperature of the electrode surface by at least 300K.

[0055] In a preferred embodiment of the reaction chamber system for thermal plasma decomposition of sulfur hexafluoride gas, the system further includes:

[0056] The main sealing system uses a fluororubber double-lip self-tightening sealing ring with a temperature resistance of ≥500℃.

[0057] The mechanical seal structure includes eight high-strength alloy bolts equidistantly distributed along the circumference of the cavity flange, which are preloaded with a preload of 25±2 N·m by a hydraulic torque system.

[0058] The gas leak monitoring unit is modularly arranged on the outside of the cavity door sealing interface, with a response time of ≤0.5 seconds.

[0059] In a preferred embodiment of the reaction chamber system for thermal plasma decomposition of sulfur hexafluoride gas, the gas leakage monitoring unit performs point detection based on the initial enrichment effect of the leaking gas at the reaction chamber door. When the detected concentration is ≥20ppm, an audible and visual alarm is triggered, and when it is ≥50ppm, an emergency shutdown is initiated.

[0060] In a preferred embodiment of the reaction chamber system for thermal plasma decomposition of sulfur hexafluoride gas, the reaction gas includes SF6, H2 and Ar, which are instantaneously mixed through the three-dimensional spiral flow channel configuration of the gas cyclone, with a mixing uniformity fluctuation of ≤±5%.

[0061] In a preferred embodiment of the reaction chamber system for thermal plasma decomposition of sulfur hexafluoride gas, the outer wall of the reaction chamber is provided with a jacketed water cooling system.

[0062] In one embodiment, a gas cyclone is a mechanical structural component that enables the gas flow entering the reaction chamber to generate a stable rotating flow. Through its flow channel design, the gas cyclone allows the reacting gas to simultaneously obtain axial and tangential velocity components, effectively: (1) driving arc motion: by creating a rotating gas flow field, the arc root of the arc continuously moves on the electrode surface, avoiding local overheating and significantly extending the electrode's service life. (2) optimizing temperature distribution: promoting uniform temperature distribution in the plasma region, eliminating local low-temperature zones, and effectively suppressing low-fluorine sulfides (SF6). X (3) Enhanced mixing effect: The instantaneous and thorough mixing of reactant gases is achieved through a symmetrically distributed inlet structure, which improves reaction efficiency and reduces the amount of reactive gases, such as H2. (4) Stabilized arc morphology: The downward velocity component generated can constrain the arc morphology, improve discharge stability, and effectively concentrate the reactant gases to the high-temperature region at the center of the arc. The gas cyclone preferably adopts a structure of four inclined inlets symmetrically distributed in a counterclockwise direction. The specific structural parameters of the cyclone, including the number of inlets, the inclination angle and the distribution diameter, are precisely designed according to the specific plasma power level and gas flow requirements to ensure the realization of the above-mentioned flow field control function.

[0063] This design employs a three-dimensional spiral flow channel configuration with four inlets circumferentially distributed. The axis of each inlet channel forms a constant tangential deflection angle of 18°±2° with the radial reference plane of the reaction chamber. This geometry induces a controlled Coriolis effect in the Ar / H2 / SF6 mixed gas during injection, and its velocity vector can be decomposed into an axial component (ensuring axial gas propulsion) and a tangential component (inducing rotational flow). Through computational fluid dynamics optimization, a specific tilt angle design allows the gas to complete the flow state transition within 0.1 ms, forming a steady-state three-dimensional vortex flow field that runs through the entire plasma reaction zone. The centrifugal effect generated by the rotating airflow causes the reactant gas to continuously converge towards the plasma axis region, forming a high-temperature core region with a smaller diameter and higher energy density. The synergistic effect of the gas tangential velocity component and axial velocity significantly increases the residence time of active particles in the reaction zone, ensuring that SF6 molecules accumulate the energy required for sufficient degradation. Simultaneously, the three-dimensional vortex field effectively promotes uniform mixing of reactants, eliminates local low-temperature zones caused by temperature gradients, and reduces the amount of by-products generated by approximately 40%. Dynamic rotating airflow drives the arc root to move continuously along the electrode surface at a predetermined frequency, transforming the concentrated heat load of the traditional fixed-point discharge mode into a uniformly distributed surface heat flow. This periodic heat load distribution reduces the peak temperature of the electrode surface by approximately 300K, fundamentally preventing localized melting. Combined with the continuous cooling effect of directional airflow on the electrode surface, the service life of the copper electrode can be increased by 3-5 times, significantly reducing system maintenance frequency and operating costs. A staged optimized reaction path is constructed based on the synergy of the gas cyclone separator and the gas reaction chamber, significantly improving gas degradation efficiency and process stability. As a highly efficient airflow organization device, the gas cyclone generator generates strong swirling motion of gas through its inlet structure, offering the following outstanding advantages: (1) By forming a stable vortex field, it achieves instantaneous and uniform mixing of the reactant gases, ensuring sufficient contact of the active components; (2) It drives the arc root to move continuously on the electrode surface, effectively avoiding local overheating and significantly extending the electrode's service life; (3) The optimized flow field distribution allows the reactant gases to converge more effectively into the high-temperature core region of the plasma, greatly improving energy utilization efficiency; (4) By adjusting the swirling intensity, it can adapt to different gas ratios and flow conditions, exhibiting good operational flexibility. These characteristics make the gas cyclone generator a key component for improving the overall performance of the SF6 degradation system.

[0064] The reaction chamber is a cylindrical cavity with a diameter of 40 cm and a height of 40 cm. A cyclone separator, through its four-inlet symmetrical structure, generates a strong rotating airflow, ensuring thorough mixing and rapid decomposition of the reactant gases within the high-temperature core region (4000-6000 K) formed by the plasma torch, guaranteeing the complete dissociation of SF6 molecules into atomic states. The gas reaction chamber located below the plasma torch, through its specific volume and structural design, provides a controllable, slow-speed cooling environment for the high-temperature gases (cooling rate 10²-10³ K / s). Utilizing the adiabatic expansion effect of the reactant gases entering the chamber through a narrow gas path—when the high-temperature gases enter the 120 mm diameter reaction chamber from the 8 mm diameter plasma channel, their volume instantly expands 225 times, achieving initial cooling through the Joule-Thomson effect. This process works in conjunction with the chamber wall water-cooling system, where circulating cooling water in the interlayer carries away residual heat at a flow rate of 3 m / s. During this process: (a) the free radical recombination reaction proceeds fully, with hydrogen atoms preferentially combining with fluorine atoms to generate stable HF; (b) sulfur atoms nucleate and grow to form easily collectable elemental sulfur particles; and (c) a natural diffusion mechanism ensures effective separation of gaseous and solid products. Through a gradient reaction strategy of "high-temperature decomposition - slow cooling," the SF6 degradation rate is increased to over 99%, while the generation of harmful byproducts is controlled below 0.1%. The spatial coupling design of the hydrocyclone and reaction chamber ensures both the efficiency of the initial decomposition and the integrity of the subsequent product conversion, forming a highly efficient and reliable end-to-end processing system.

[0065] The sealing integrity of the reaction chamber is the core guarantee for ensuring the safe and efficient operation of the plasma degradation process. Its important functions are mainly reflected in: (a) preventing environmental hazards and personnel injury caused by toxic gas leakage; (b) maintaining a stable pressure environment for the reaction system, ensuring the controllability of the gas flow field distribution and reaction kinetics; (c) avoiding oxygen pollution caused by the entry of outside air, preventing the generation of unwanted byproducts; and (d) ensuring the stability of plasma discharge and improving energy utilization efficiency. This design adopts a multi-layered composite sealing scheme, based on the following core principles:

[0066] Material compatibility principle: Sealing materials must be able to withstand high-temperature radiation, chemical corrosion, and plasma irradiation simultaneously.

[0067] Pressure gradient adaptation principle: Based on the pressure distribution characteristics inside the cavity, a differentiated sealing level design is adopted.

[0068] Thermal expansion compensation mechanism: The structural design is used to offset the differences in thermal expansion of different materials at high temperatures.

[0069] Failure safety protection: Install double sealing barriers and a leak detection system.

[0070] This design has been further optimized as follows:

[0071] (a) Main sealing system: Fluororubber is used instead of nitrile rubber as the core sealing material, which improves its temperature resistance to 500°C and significantly enhances its resistance to corrosion from fluorinated media. The sealing ring adopts a double-lip self-tightening structure, which can automatically enhance the sealing effect when the system pressure increases.

[0072] (b) Mechanical Seal System: For the sealing of the reaction chamber door, this system employs eight high-strength alloy bolts to form a uniformly distributed load sealing structure. These bolts are equidistantly distributed along the circumference of the chamber door flange, and a precise preload (design value 25±2 N·m) is applied via a hydraulic torque system to ensure uniform pressure distribution at the sealing interface. This effectively compensates for the elastic decay of the fluororubber sealing ring at high temperatures. This design ensures complete contact of the sealing surface under pressure while avoiding permanent deformation of the sealing ring due to over-tightening, significantly improving the equipment's maintenance cycle and operational reliability.

[0073] (c) Gas leak monitoring unit:

[0074] This system incorporates modular gas leak monitoring units at key locations on the outside of the reaction chamber. Based on experimental results, this design places the detection nodes directly outside the chamber door sealing interface, where leaks are most likely to occur. This layout fully utilizes the initial enrichment effect of leaking gas at the chamber door, enabling the monitoring system to identify gas leaks with the shortest possible response time (≤0.5 seconds). The monitoring units employ a pluggable modular design, allowing for quick replacement of the corresponding sensor module based on the characteristics of the gas being processed. Spare module slots are reserved for expanding detection capabilities for other gases.

[0075] The system achieves intelligent monitoring through a multi-level early warning mechanism: when the detected concentration exceeds the threshold (generally set at 20 ppm), it automatically triggers an audible and visual alarm and adjusts the air intake flow in real time; if the concentration continues to rise to 50 ppm, the system will immediately initiate an emergency shutdown procedure. This optimized layout based on physical location improves leak detection efficiency by approximately 60% compared to traditional distributed layouts, establishing a reliable safety barrier for the system.

[0076] In one embodiment, a three-dimensional spiral flow channel configuration with four symmetrically distributed inlets is employed. Through precise control of the tangential deflection angle (18°±2°), a stable three-dimensional vortex flow field is formed in the reactant gas within an extremely short time (0.1 ms). This design not only significantly improves the residence time and mixing uniformity of the gas in the high-temperature core region but also effectively drives the arc motion through dynamic rotating airflow, reducing electrode heat load and extending equipment life. The linkage between the cyclone separator and plasma power further achieves synergistic optimization of the flow field, temperature field, and reaction field.

[0077] Employing a gradient reaction path of "high-temperature decomposition - slow cooling," combined with the adiabatic expansion effect of the gas and a jacketed water-cooling system, rapid and controllable cooling of the high-temperature gas is achieved. The cavity structure design allows the gas to cool naturally during expansion, while ensuring that free radicals fully recombine into stable products (such as HF and elemental sulfur), effectively inhibiting the formation of harmful byproducts and increasing the SF6 degradation rate to over 99%. The system constructs a mechanical seal structure with a fluororubber sealing ring as the core and eight high-strength bolts evenly distributed and tightened, combined with a modular gas leak monitoring unit, forming a triple safety guarantee of "structural sealing + real-time monitoring + graded response." The sensor is placed on the outside of the cavity door sealing interface, achieving rapid response (≤1 second) based on the initial enrichment effect of leaked gas, significantly improving the reliability and environmental safety of system operation. Through the organic integration of the cyclone separator, reaction cavity, sealing system, and monitoring unit, dynamic matching of airflow organization, reaction path, and equipment status is achieved. The system has the ability to adapt to different gas ratios, flow rates, and power conditions, improving degradation efficiency while optimizing energy consumption and equipment maintenance cycles. With "structural innovation, process control, and safety assurance" as the main focus, an SF6 treatment system with efficient degradation, intelligent regulation, and reliable operation characteristics has been constructed, providing a complete technical solution for the power industry to achieve the harmless and resource-based treatment of SF6 gas.

[0078] Furthermore, the cyclone separator of this invention adopts a three-dimensional spiral flow channel configuration with four inlets circumferentially counter-clockwise symmetrical distribution. The axis of each inlet maintains a constant tangential deflection angle of 18°±2° with the radial reference plane of the reaction chamber. This geometric parameter is optimized through computational fluid dynamics, enabling the Ar / H2 / SF6 mixed gas to generate a controlled Coriolis effect at the moment of injection (within 0.1ms). The velocity vector is precisely decomposed into an axial component (ensuring axial gas propulsion) and a tangential component (inducing rotational flow). The three-dimensional vortex flow field driven by the tangential component generates a strong centrifugal effect, continuously converging the reactant gas to the high-temperature core region of the plasma (4000–6000K), forming a miniature reaction zone with higher energy density. At the same time, the periodic directional cooling effect of the rotating airflow on the electrode surface causes the arc root to move continuously along the electrode at a predetermined frequency, transforming the concentrated heat load of traditional fixed-point discharge into a uniformly distributed surface heat flow. The peak electrode temperature is reduced by 300K, fundamentally eliminating the risk of local melting. Furthermore, the turbulent diffusion effect of the vortex flow field achieves instantaneous uniform mixing of the reactant gases (concentration fluctuation ≤ ±5%), ensuring sufficient contact between fluorine radicals and H2 molecules, and effectively suppressing low-fluorine sulfides (SF6). XByproducts such as SF6 and sulfur atoms are generated. The reaction chamber (a cylindrical structure with a diameter of 40 cm and a height of 40 cm) achieves a gradient reaction path of "high-temperature decomposition - slow cooling" through spatial coupling design. When the high-temperature gas enters the chamber from the plasma torch outlet (8 mm in diameter), its volume expands 225 times due to adiabatic expansion (8 mm → 120 mm inlet), achieving initial cooling through the Joule-Thomson effect; the chamber wall jacketed water cooling system (circulating cooling water flow rate of 3 m / s) synergistically controls the cooling rate within the range of 10²–10³ K / s. This slow cooling environment allows the active free radicals (F•S•) after high-temperature decomposition to fully recombine under a controllable temperature gradient: hydrogen atoms (H•) preferentially combine with fluorine atoms (F•) to generate stable HF (gas), sulfur atoms (S•) grow through nucleation to form collectable elemental sulfur particles (solid), and the gas-solid products are efficiently separated through natural diffusion mechanism. This process avoids byproduct residues caused by rapid cooling, ensuring a stable SF6 degradation rate ≥99% and a harmful byproduct generation amount ≤0.1%.

[0079] The sealing system employs a three-layer synergistic protection mechanism: Material layer: A fluororubber double-lip self-tightening sealing ring (temperature resistant up to 500℃, resistant to fluorine-containing media corrosion) automatically enhances the seal when pressure increases; Structural layer: Eight high-strength alloy bolts are evenly distributed circumferentially along the cavity flange, with a hydraulic torque system applying a preload of 25±2 N·m to compensate for the elastic decay of the sealing ring at high temperatures, ensuring uniform pressure distribution at the interface; Monitoring layer: Modular gas monitoring units are strategically positioned on the outside of the cavity sealing interface, utilizing the initial enrichment effect of leaked gas at the sealing interface to achieve a rapid response of ≤0.5 seconds. When the HF concentration is ≥20ppm, an audible and visual alarm is triggered and the intake flow rate is automatically adjusted; when it is ≥50ppm, an emergency shutdown is initiated, improving leak detection efficiency by 60% compared to traditional solutions. This system, through closed-loop control of "structural self-adaptation - real-time monitoring - graded response," completely eliminates the risk of toxic gas leakage while maintaining a stable pressure environment (±0.1 kPa) within the reaction chamber, ensuring the stability of the arc discharge and the controllability of reaction kinetics. This invention systematically solves the core problems of uneven mixing, by-product generation, electrode ablation and leakage risks in the SF6 degradation process by deeply coupling three technical means: precise flow field control of the cyclone (to achieve gas mixing uniformity and arc stability), gradient thermal management of the reaction chamber (to ensure the integrity of product conversion), and failure safety protection of the sealing system (to build an active safety defense line). It provides the power industry with a harmless treatment technology solution that can be industrially applied.

[0080] The basic principles of this application have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this application are merely examples and not limitations, and should not be considered as essential features of each embodiment of this application. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the application to the necessity of employing the aforementioned specific details for implementation.

[0081] The above description has been given for illustrative and descriptive purposes. Furthermore, this description is not intended to limit the embodiments of this application to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

Claims

1. A reaction chamber system for thermal plasma decomposition of sulfur hexafluoride gas, characterized in that, It includes, The reaction chamber includes a high-temperature core region for forming plasma at 4000–6000 K. The gas cyclone is a three-dimensional spiral flow channel configuration with four inlets evenly distributed circumferentially on the reaction chamber. It includes four inclined air inlets evenly distributed counterclockwise along the circumferential direction, so that the reaction gas forms a steady three-dimensional vortex flow field that runs through the plasma reaction zone within 0.1 ms after injection. The three-dimensional vortex flow field simultaneously provides an axial velocity component to propel the gas flow, a tangential velocity component to drive the arc root to move continuously on the electrode surface, and converges the reaction gas to the high-temperature core region of the plasma through centrifugal effect.

2. The reaction chamber system for thermal plasma decomposition of sulfur hexafluoride gas as described in claim 1, characterized in that, Preferably, the axis of each air inlet forms a constant tangential deflection angle of 18°±2° with the radial reference plane of the reaction chamber.

3. The reaction chamber system for thermal plasma decomposition of sulfur hexafluoride gas as described in claim 1, characterized in that, The gas cyclone includes, PTFE base, The cathode is located on top of the polytetrafluoroethylene base. The anode is spaced relative to the cathode and disposed at the bottom of the polytetrafluoroethylene base. A suspended anode, disposed on the polytetrafluoroethylene base and located between the cathode and the anode, and parallel to the anode. Air inlet 1 is located between the polytetrafluoroethylene base, the cathode, and the suspended anode. Air inlet 1 has four inclined air inlets evenly distributed in a counterclockwise direction along the circumference. Air inlet 2 is located between the polytetrafluoroethylene base and the anode and the suspended anode. Air inlet 2 has four inclined air inlets evenly distributed in a counterclockwise direction along the circumference. The air inlet 3 is located on the polytetrafluoroethylene base and on the side of the anode away from the cathode. The air inlet 2 has four inclined air inlets evenly distributed in a counterclockwise direction along the circumference.

4. The reaction chamber system for thermal plasma decomposition of sulfur hexafluoride gas as described in claim 3, characterized in that, The axial distance between air inlet 1 and air inlet 2 is less than the axial distance between air inlet 2 and air inlet 3.

5. The reaction chamber system for thermal plasma decomposition of sulfur hexafluoride gas as described in claim 1, characterized in that, The gas cyclone has a plasma channel with a diameter of 8 mm and an inlet diameter of 120 mm. The high-temperature gas expands 225 times through adiabatic expansion, forming a controllable cooling rate of 10²–10³ K / s.

6. The reaction chamber system for thermal plasma decomposition of sulfur hexafluoride gas as described in claim 1, characterized in that, The tangential velocity component drives the arc root to move continuously along the electrode surface at a predetermined frequency, thereby reducing the peak temperature of the electrode surface by at least 300K.

7. The reaction chamber system for thermal plasma decomposition of sulfur hexafluoride gas as described in claim 1, characterized in that, Also includes: The main sealing system uses a fluororubber double-lip self-tightening seal ring with a temperature resistance of ≥500℃. The mechanical seal structure includes eight high-strength alloy bolts equidistantly distributed along the circumference of the cavity flange, which are preloaded with a preload of 25±2 N·m by a hydraulic torque system. The gas leak monitoring unit is modularly arranged on the outside of the cavity door sealing interface, with a response time of ≤0.5 seconds.

8. The reaction chamber system for thermal plasma decomposition of sulfur hexafluoride gas as described in claim 1, characterized in that, The gas leak monitoring unit performs point detection based on the initial enrichment effect of leaked gas at the reaction chamber door. When the detected concentration is ≥20ppm, an audible and visual alarm is triggered, and when it is ≥50ppm, an emergency shutdown is initiated.

9. The reaction chamber system for thermal plasma decomposition of sulfur hexafluoride gas as described in claim 1, characterized in that, The reactant gases include SF6, H2 and Ar, which are instantaneously mixed through the three-dimensional spiral flow channel configuration of the gas cyclone, with a mixing uniformity fluctuation of ≤±5%.

10. The reaction chamber system for thermal plasma decomposition of sulfur hexafluoride gas as described in claim 1, characterized in that, The outer wall of the reaction chamber is equipped with a jacketed water cooling system.

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