SF6 waste gas degradation device and method based on gas-solid reaction strengthening

Abstract

The application discloses a kind of based on gas-solid reaction strengthening SF6 waste gas degradation device and method.The device includes plasma generator, gas-solid separation reactor, tail gas treatment device and gas distribution system;Gas distribution system is connected with plasma generator, SF6 and auxiliary gas are gas distribution, mixed ionization is carried out to obtain plasma torch, powder bin is provided at the plasma inlet of gas-solid separation reactor, powder-like porous active solid material is contacted with plasma torch and heated, and powder-like solid reactant and non-basic tail gas are generated, gas-solid separation bin carries out gas-solid separation to tail gas and solid reactant after reaction, and separated non-basic tail gas is subjected to secondary reaction to realize harmless treatment.The application solves the technical problem that the related art does not have high flow for SF6 degradation, and realizes convenient, efficient, reliable and low-cost degradation treatment of SF6 waste gas.

Description

Technical Field

[0001] This invention relates to the field of power grid equipment exhaust gas treatment technology, and in particular to an SF6 exhaust gas degradation device and method based on gas-solid reaction enhancement. Background Technology

[0002] Sulfur hexafluoride (SF6), a gas with excellent insulating and arc-quenching properties, is widely used in power grid equipment such as high-voltage circuit breakers and transformers, playing a crucial role in the safe and stable operation of power systems. However, SF6 is one of the most potent greenhouse gases known, with a global warming potential (GWP) 23,900 times that of carbon dioxide (CO2) and an atmospheric retention time of up to 3,200 years, significantly impacting ozone layer depletion and climate change. With the upgrading of power grid equipment, the harmless treatment of large quantities of waste SF6 gas has become a core challenge for environmental protection and emission reduction in the power industry.

[0003] Currently, the main technologies for treating sulfur hexafluoride (SF6) waste gas include high-temperature incineration, catalytic hydrolysis, and low-temperature plasma degradation. High-temperature incineration decomposes SF6 at high temperatures (typically >1000℃), but it suffers from extremely high energy consumption, low flow rates (mostly <10 L / h), and the easy generation of toxic byproducts (such as sulfur trioxide (SO3) and hydrogen fluoride (HF). Furthermore, it requires a complex tail gas purification system, resulting in high operating costs. Catalytic hydrolysis utilizes a catalyst to promote the reaction of SF6 with water at a specific temperature, but the catalyst is susceptible to fluoride poisoning and deactivation, leading to unstable degradation efficiency (typically <95%) and sensitivity to fluctuations in SF6 concentration, making it difficult to adapt to the complex composition of actual waste gases.

[0004] Low-temperature plasma technology has become a research hotspot in recent years due to its mild reaction conditions and high decomposition efficiency. However, existing technologies still have significant limitations: the processing flow rate is generally low (laboratory scale is generally less than 5 L / h), making it difficult to meet industrial-grade treatment needs; harmful byproducts such as sulfur dioxide (SO2) and oxygen difluoride (OF2) are easily generated during the degradation process (generation amount >1%), requiring additional treatment steps and further increasing costs. For example, dielectric barrier discharge (DBD) plasma utilizes dielectric barrier discharge, which is easily corroded by the dielectric. The processing flow rate of a single reaction tube is not high. At a discharge power of 1kW, the processing flow rate for 2% sulfur hexafluoride (SF6) waste gas is only 150 mL / min, equivalent to a processing capacity of 0.18 L / h of SF6. Moreover, the degradation rate decreases significantly with increasing SF6 concentration, making it difficult to meet the degradation needs of large quantities of SF6.

[0005] Related technologies include portable devices and methods for degrading sulfur hexafluoride (SF6) using atmospheric pressure microwave plasma. However, portable devices have low processing flow rates, up to 40 L / h, which is insufficient to meet the requirements of centralized processing. Furthermore, these devices require the plasma torch to fully adsorb and react with porous active materials. Simply increasing the size of the device proportionally would lead to a decrease in the reaction rate, making it difficult to meet higher flow rate processing requirements.

[0006] In summary, the existing technology for sulfur hexafluoride (SF6) degradation has a low treatment flow rate, resulting in low degradation efficiency of SF6. Summary of the Invention

[0007] Based on this, the present invention provides an SF6 waste gas degradation device and method based on gas-solid reaction enhancement, so as to at least solve the problems of low treatment flow rate and difficulty in suppressing harmful by-products in the related technologies for SF6 degradation.

[0008] According to one aspect of the present invention, an SF6 waste gas degradation device based on gas-solid reaction enhancement is provided, comprising: a plasma generator, a gas-solid separation reactor, a tail gas treatment device, and a gas distribution system; the gas distribution system is used to mix SF6 with an auxiliary gas; the plasma generator is connected to the gas distribution system and is used to ionize the mixture of SF6 and the auxiliary gas to obtain a plasma torch, and to eject the plasma torch into the gas-solid separation reactor in an ejection direction; the gas-solid separation reactor includes a plasma inlet and a gas-solid separation chamber, a powder silo is provided at the plasma inlet, and the powder silo stores a powdered porous active solid material, the powder... A porous active solid material is brought into contact with and heated by the plasma torch. The gas-solid separation chamber is vertically arranged, with an opening at the top connected to the plasma inlet. An outlet is also provided at the top of the chamber, and a discharge port is provided at the bottom. The gas-solid separation chamber is used to react the heated powdered porous active solid material with the plasma, generating powdered solid reactants and non-alkaline tail gas, and then separating the tail gas and solid reactants. The tail gas treatment device is connected to the outlet of the gas-solid separation chamber and is used to perform a secondary reaction on the non-alkaline tail gas discharged from the outlet to achieve harmless treatment.

[0009] As an optional embodiment, the gas-solid separation chamber includes a cylindrical section and a conical section connected sequentially from top to bottom; the opening is located at the top of the cylindrical section, the opening is connected to the plasma inlet, and the plasma inlet is tangent to the cylindrical section; the discharge port is located at the bottom of the conical section, and a waste bin is also provided below the discharge port, with a second discharge valve provided at the inlet of the waste bin.

[0010] As an alternative, the shape and size of the opening are the same as those of the plasma inlet, which is cylindrical with a diameter of 3-20 cm; the diameter of the cylindrical portion is 5-30 cm, and its length in the vertical direction is 10-60 cm; the length of the conical portion in the vertical direction is 15-80 cm, the diameter of the top end is the same as that of the cylindrical portion, and the diameter of the bottom end is 2-6 cm.

[0011] As an alternative, in the vertical direction, the top of the outlet pipe is not higher than the lower edge of the plasma inlet.

[0012] As an alternative, in the vertical direction, the distance between the top of the outlet pipe and the bottom edge of the plasma inlet is 5-20 cm; the diameter of the outlet 305 is 2-15 cm; and in the vertical direction, the distance between the top of the outlet pipe and the top of the cylindrical part is 8-25 cm.

[0013] As an alternative, the output gas of the exhaust gas treatment device is also connected to the nozzle through a fourth gas path; the discharge port at the bottom of the gas-solid separation chamber is also connected to the fourth gas path.

[0014] As an alternative, the powder hopper is positioned above the plasma inlet, and a first discharge valve is provided between the powder hopper and the plasma inlet for discharging the powdered porous active solid material to the plasma inlet at a fixed rate and mixing and reacting with the plasma torch.

[0015] As an optional solution, the exhaust gas treatment device is equipped with a mixed solution of sodium hydroxide (NaOH) and calcium hydroxide (Ca(OH)2) with a capacity of 5-15L; the concentration of sodium hydroxide (NaOH) is 0.5-0.8 mol / L, and the concentration of calcium hydroxide (Ca(OH)2) is 0.2-0.5 mol / L; the mixed solution also contains solid particles to ensure that the gas-liquid contact time is ≥10 s.

[0016] As an alternative, the porous active solid material is a mesoporous material having a hierarchical pore structure comprising micron- and nanopores, with a porosity of 0.5-0.8 cm⁻¹. 3 / g, the layered pore structure contains mesopores, the diameter of which is 10nm-40nm.

[0017] As an alternative, the plasma torch includes HF, SO2, and SOF ion / molecular products; the main component of the porous active solid material is a metal oxide; the metal oxide includes at least one of the following: iron oxide, Al2O3, MgO, CaO.

[0018] As an alternative, the plasma generator includes a nozzle, a waveguide device, and a discharge tube; the waveguide device is a rectangular waveguide; the rectangular waveguide has mounting holes that match the cross-sectional shape of the discharge tube; the nozzle is a multi-gas-channel nozzle; the multiple gas channels of the nozzle include a first channel for transmitting the auxiliary gas, a second channel for transmitting the SF6, and a third channel for recovering a portion of the powdered porous active solid material; the discharge tube is a double-layered cylindrical tube, which includes an outer tube and an inner tube, the outer tube being fixed to the waveguide device, and the nozzle being disposed at one end of the inner tube to house the plasma torch within the inner tube.

[0019] As an optional configuration, the rectangular waveguide has a power of 1-50 kW; the plasma torch is 15-75 cm long; the inner tube can withstand high temperatures ≥1500℃; the inner tube has a diameter of 2-7 cm and a length of 4-25 cm; the outer tube has a diameter of 3-20 cm and a length of 20-120 cm; the outer tube has a larger diameter than the inner tube; and the radial distance between the outer tube and the inner tube is 1-10 cm.

[0020] As an optional embodiment, the gas distribution system includes an SF6 gas source, an auxiliary gas source, a steam generator, and an air compressor; the first gas path of the auxiliary gas source is connected to the first channel of the nozzle; the second gas path of the SF6 gas source is connected to the first pressurized gas path of the air compressor, and the second gas path of the SF6 gas source is also connected to the second channel of the nozzle; the third gas path of the steam generator is connected to the second pressurized gas path of the air compressor; both the first pressurized gas path and the second pressurized gas path are connected to the nozzle.

[0021] According to another aspect of the present invention, a method for degrading SF6 waste gas based on gas-solid reaction enhancement is also provided, comprising: mixing SF6 with an auxiliary gas through a gas mixing system and inputting the mixture into a plasma generator; mixing the SF6 and the auxiliary gas through the plasma generator, ejecting the mixture in a predetermined ejection direction, and ionizing the mixture to form a plasma torch; adding a powdered porous active solid material to the plasma torch to adsorb the particles of the plasma torch and cause a chemical reaction, thereby generating powdered solid reactants and non-alkaline tail gas, and separating the residue in a gas-solid separation chamber in the ejection direction of the plasma torch. The solid reactants and the non-alkaline tail gas are separated. The gas-solid separation reactor includes a plasma inlet and a gas-solid separation chamber. A powder hopper is provided at the plasma inlet, and the powder hopper stores powdered porous active solid material. The gas-solid separation chamber is vertically arranged, with an opening at the top that is connected to the plasma inlet. An outlet is also provided at the top of the gas-solid separation chamber, and a discharge outlet is provided at the bottom. The non-alkaline tail gas is transferred to a tail gas treatment device, where it undergoes a secondary reaction in an alkaline solution to achieve harmless treatment.

[0022] As an optional approach, before the SF6 and auxiliary gas are mixed through a gas distribution system and input into the plasma generator, the method further includes: inputting the auxiliary gas and opening the powder hopper, forming a gas circulation through the gas-solid separation chamber and a fourth gas path connected to the outlet of the gas-solid separation chamber, and then closing the powder hopper; after the solid reactants and the non-alkaline tail gas are separated in the gas-solid separation chamber in the direction of plasma torch emission, the method further includes: recovering the separated solid reactants to the waste hopper and opening the powder hopper for replenishment to continue the reaction with the plasma torch; after the non-alkaline tail gas is transferred to the tail gas treatment device for secondary reaction and harmless treatment through the alkaline solution in the tail gas treatment device, the method further includes: transferring the output gas of the tail gas treatment device to the nozzle as an auxiliary gas for plasma reaction.

[0023] The present invention has the following technical effects:

[0024] 1. This invention first solidifies the particles related to harmful byproduct gases in the plasma torch through powder mixing, and then performs harmless treatment in conjunction with a tail gas treatment device. Compared with existing technologies that only use alkaline washing devices, this significantly improves the treatment efficiency and suppression effect of harmful byproducts, thereby enabling higher flow rate ion treatment. Compared with the existing maximum treatment flow rate of 40 L / h for sulfur hexafluoride (SF6), this invention significantly increases the treatment flow rate while maintaining the same treatment efficiency, achieving a several-fold increase and solving the problem of low treatment flow rate for SF6 degradation in existing technologies.

[0025] 2. This invention uses powdered porous active solid materials to react with the plasma torch, resulting in a more thorough reaction. While increasing the processing flow rate, it can ensure the reaction rate and efficiency. Then, the powdered solid reactants are separated from the non-alkaline tail gas through the gas-solid separation chamber, thus solidifying the harmful gaseous elements in the plasma torch and ensuring the treatment effect. This avoids the deterioration of the treatment effect due to the increase in flow rate. Attached Figure Description

[0026] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention, and those skilled in the art can obtain other embodiments based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of an SF6 waste gas degradation device based on gas-solid reaction enhancement, according to an embodiment of the present invention.

[0028] Figure 2 This is a schematic diagram of the gas-solid separation chamber according to an embodiment of the present invention.

[0029] Figure 3 yes Figure 2 Top view;

[0030] Figure 4 This is a flowchart of an embodiment of the present invention of an SF6 waste gas degradation method based on gas-solid reaction enhancement.

[0031] Figure 5 This is a schematic diagram showing the component detection results in the final emitted gas of an embodiment of the present invention.

[0032] In the diagram: 1. Gas distribution system; 101. Auxiliary gas source; 102. SF6 gas source; 103. Air compressor; 104. Steam generator; 105. First flow meter; 106. Second flow meter; 107. Third flow meter; 108. Fourth flow meter; 2. Plasma generator; 21. Nozzle; 201. First channel; 202. Second channel; 203. Third channel; 204. Rectangular waveguide; 205. Inner tube; 206. Outer tube; 3. Gas-solid separation reactor; 301. Powder silo; 302. Powdered porous active solid material; 303. First discharge valve; 304. Plasma inlet; 305. Gas outlet; 306. Cylindrical section; 307. Conical section; 308. Second discharge valve; 309. Waste silo; 4. Tail gas treatment device. Detailed Implementation

[0033] Embodiments of the present invention will now be described in more detail with reference to the accompanying drawings. While some embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the drawings and embodiments of the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0034] Atmospheric pressure microwave plasma technology employs electrodeless discharge and high energy density. The electron temperature of the plasma (average 5-15 eV) is higher than that of DBD (average 2-5 eV), resulting in stronger bombardment capability and higher plasma ionization, which better promotes the effective degradation of sulfur hexafluoride (SF6) and its intermediate products. Furthermore, microwave plasma is a high-enthalpy plasma with a higher particle temperature than DBD, thus exhibiting high reactivity. This provides a new method for the degradation treatment of SF6 waste gas that is highly energy-efficient (greater than 0.8 L / kWh) and has a high degradation efficiency (degradation rate greater than 0.8 L / h at 1 kW power). This embodiment provides a gas-solid reaction-enhanced SF6 waste gas degradation device and method, aiming to solve the problems of low flow rate and difficulty in suppressing harmful byproducts in SF6 degradation treatment, and to achieve convenient, efficient, reliable, and low-cost degradation treatment of SF6 waste gas.

[0035] Among related technologies, there exists a harmless treatment device for SF6 waste gas degradation using atmospheric pressure microwave plasma. This device is configured via a gas distribution system to mix SF6 with an auxiliary gas. A plasma generator ionizes the mixture of SF6 and the auxiliary gas to create a plasma torch, which is then ejected into a plasma reactor. Inside the plasma reactor, a porous active solid material contacts and is heated by the plasma torch, spontaneously reacting with molecules / ions within the torch to generate solid reactants and non-alkaline tail gas. The non-alkaline tail gas undergoes a secondary reaction in a tail gas treatment device to achieve harmless treatment. This solves the problem of difficult-to-suppress harmful byproducts.

[0036] This invention first solidifies the particles related to harmful byproduct gases in the plasma torch and then treats them harmlessly using a tail gas treatment device. Compared to existing technologies that only use alkaline washing devices, this significantly improves the treatment efficiency and suppression effect of harmful byproducts, thereby enabling higher flow rates for ion treatment. Compared to the existing SF6 treatment flow rate of 0.18 L / h, this invention substantially increases the treatment flow rate, solving the problem of low treatment flow rates for SF6 degradation in existing technologies.

[0037] This enables convenient, efficient, reliable, and low-cost degradation treatment of SF6 waste gas. The treatment device has a simple structure and a small overall size, with the size of the equipment in the decimeter range. Compared with DBD treatment equipment, which is at least several meters in size, it has significant portability, greater flexibility of use, and is more suitable for the SF6 waste gas treatment needs of widely distributed high-voltage gas insulation equipment.

[0038] However, this processing device can only handle a maximum flow rate of 40 L / h, while sulfur hexafluoride (SF6) gas is widely used in power equipment and requires continuous replacement, resulting in a large quantity being generated. Portable processing devices offer high mobility and flexibility, but cannot meet higher processing flow rates, thus limiting their application scenarios.

[0039] Example 1

[0040] According to one aspect of the present invention, an SF6 waste gas degradation device based on gas-solid reaction enhancement is provided, such as... Figure 1 As shown, the device includes: a plasma generator 2, a gas-solid separation reactor 3, a tail gas treatment device 4, and a gas distribution system 1. The plasma generator 2 and the gas-solid separation reactor 3 can be collectively referred to as the atmospheric pressure microwave plasma generator 2.

[0041] Gas distribution system 1 is connected to plasma generator 2. Gas distribution system 1 is configured to mix sulfur hexafluoride (SF6) with an auxiliary gas. Plasma generator 2 is connected to gas distribution system 1 and is configured to ionize the mixture of SF6 and auxiliary gas to obtain a plasma torch, which is then ejected into gas-solid separation reactor 3 in the ejection direction. Simultaneously with the plasma reaction, the powdered porous active solid material 302 is heated by the plasma torch to increase the reaction rate between the powdered porous active solid material 302 and the molecules or ions in the plasma torch.

[0042] The gas-solid separation reactor 3 includes a plasma inlet 304 and a gas-solid separation chamber. A powder silo 301 is located at the plasma inlet 304, storing powdered porous active solid material 302. The powdered porous active solid material 302 comes into contact with the plasma torch and is heated, forming a chemical reaction system that ultimately produces powdered solid reactants and non-alkaline tail gas. The gas-solid separation chamber separates the tail gas and solid reactants after the reaction, such as... Figure 3 As shown, the gas-solid separation chamber includes a cylindrical portion 306 and a conical portion 307. An air outlet 305 is provided at the top of the cylindrical portion 306.

[0043] In the above-mentioned chemical reaction system, at the high temperature of the plasma torch, the powdered porous active solid material 302 can spontaneously react with the molecules or ions of the plasma torch without the need for a catalyst or other reaction conditions.

[0044] The gas-solid separation chamber has an opening at the top, which connects to the plasma inlet 304. An outlet 305 is also located at the top of the chamber, and a discharge port is located at the bottom. The chamber is used to react heated, powdered porous active solid material with plasma, generating powdered solid reactants and non-alkaline tail gas. The tail gas and solid reactants are then separated. The non-alkaline tail gas is discharged from the outlet 305 to the tail gas treatment device 4 for secondary treatment. The solid reactants are discharged from the discharge port and can be collected or recirculated through the fourth gas path to the nozzle 21 for further reaction and utilization.

[0045] This is because the gas-solid reaction is inefficient, and single use will result in the waste of most of the porous active solid material. By recycling, the porous active solid material can be recycled, which can save costs and does not affect the degradation of sulfur hexafluoride (SF6).

[0046] The plasma torch, after being ionized with the auxiliary gas, reacts with the porous active solid material to generate solid reactants and non-alkaline tail gas. The non-alkaline tail gas is then subjected to a secondary reaction by the tail gas treatment device 4 to achieve harmless treatment.

[0047] Specifically, after ionization of sulfur hexafluoride (SF6) gas and auxiliary gas, a reaction occurs in a plasma torch to generate sulfur dioxide (SO2) and sulfur-oxygen-fluorine (SOF) molecules or ions. Examples include neutral molecules containing sulfur oxides and fluorides such as SOF2 (thioyl difluoride), SOF4 (tetrafluorothionyl), SO2F2 (thioyl difluoride), SO2 (sulfur dioxide), and OF2 (oxygen difluoride). Some ions include SOF3⁺ (sulfur trifluoride ion), SOF⁺ (sulfur fluoride ion), SF3⁺ (sulfur trifluoride ion), SF5⁺ (sulfur pentafluoride ion), F⁻ (fluoride ion), and SF7⁻ (sulfur heptafluoride anion). Also included are some free radicals and reactive intermediates.

[0048] These products can be adsorbed by the powdered porous active solid material 302 and further decomposed to generate active ions, mainly some free radicals and active intermediates. They can form a chemical reaction system with the powdered porous active solid material 302, and further chemical reactions occur to generate solid compounds of fluorine (F) and sulfur (S), thereby solidifying the ions that form harmful byproducts on the powdered porous active solid material 302, reducing the formation of harmful byproduct gases. This not only greatly increases the efficiency of byproduct treatment, but also, combined with the exhaust gas treatment device 4, can achieve better harmless treatment.

[0049] It should be noted that the main components of the aforementioned powdered porous active solid material 302 require a chemical reaction system formed with molecules / ions in the plasma torch, and its free energy change... satisfy: In the formula, ΔH is the enthalpy change of the chemical reaction system, ΔS is the entropy change of the chemical reaction system, and T is the absolute temperature of the chemical reaction system, and 0 <T<4000K。

[0050] In other words, the main components of the powdered porous active solid material 302 can spontaneously react with the molecules / ions in the plasma torch to form a chemical reaction system, with the products tending to exist in solid form. Combined with the properties of porous materials, this allows for the rapid and efficient solidification of ions that would otherwise form harmful byproducts when adsorbing molecules / ions from the plasma torch. This not only improves processing efficiency but also increases the processing flow rate.

[0051] Furthermore, it avoids the ions of harmful byproducts from undergoing secondary reactions to generate harmful gaseous byproducts when forming gaseous products. This further improves the treatment efficiency of sulfur hexafluoride (SF6).

[0052] The exhaust gas treatment device 4 is connected to the output port of the gas-solid separation reactor 3, and an alkaline solution is provided inside the exhaust gas treatment device 4. Since the harmful by-product gases are generally acidic gases of fluorine oxides and sulfur oxides, the alkaline solution can fully react the small amount of gas that has not reacted with the powdered porous active solid material 302, thereby achieving harmless treatment.

[0053] As an alternative, the gas-solid separation chamber includes a cylindrical section 306 and a conical section 307 connected sequentially from top to bottom; the top of the cylindrical section 306 is connected to a plasma inlet 304, and the bottom of the conical section 307 is provided with a waste bin 309; a second discharge valve 308 is provided at the inlet of the waste bin 309.

[0054] like Figure 3 As shown, the gas-solid separation chamber includes a cylindrical part 306 and a conical part 307. The cylindrical part 306 can more easily achieve stable swirling flow to ensure the stability of gas-solid separation. The conical part 307 can shorten the space to form gas compression after the gas swirling speed decreases, thereby prolonging the gas swirling time and improving the gas-solid separation effect.

[0055] A waste bin 309 is also provided at the bottom of the conical part 307. The discharge port of the conical part 307 is connected to the waste bin 309 through a pipe. The settled powdery solid reactants can be collected and cleaned through the second discharge valve 308.

[0056] A fourth gas path is also provided on the pipeline, connecting the exhaust gas treatment device to the nozzle 21. The discharge port of the conical part 307 can also be connected to the fourth gas path, so that the settled powdered solid reactants that can be recycled can be transferred back to the nozzle 21 for reaction. On the one hand, this can save materials and costs. On the other hand, the simultaneous spraying of powdered porous active solid material 302 and sulfur hexafluoride SF6 from the nozzle 21 allows the powdered porous active solid material 302 and sulfur hexafluoride SF6 to react more fully in the entire plasma torch, ensuring the treatment efficiency and degradation rate of sulfur hexafluoride SF6, so that the degradation rate can reach 99%, close to 100%.

[0057] The plasma inlet 304 can be cylindrical. The plasma inlet 304 is tangent to the cylindrical part 306, which can make the mixed plasma torch and the powdered porous active solid material 302 form a stable swirling flow after entering the cylindrical part 306.

[0058] As an alternative, the shape and size of the opening are the same as those of the plasma inlet 304, which is cylindrical with a diameter of 3-20 cm. This ensures effective transport of gas and mixed powdered porous active solid material 302 at high flow rates, avoiding excessive deposition at the plasma inlet 304.

[0059] The cylindrical part 306 has a diameter of 5-30 cm and a vertical length of 10-60 cm; the conical part 307 has a vertical length of 15-80 cm, a top diameter that is the same as that of the cylindrical part 306, and a bottom diameter of 2-6 cm.

[0060] With the cylindrical portion 306 and conical portion 307 of the above dimensions, the gas-solid mixture can effectively rotate and float in the cylindrical portion 306 at a higher processing flow rate, and after sufficient reaction, effectively settle and aggregate in the conical portion 307.

[0061] As an alternative, in the vertical direction, the top of the outlet 305 is not higher than the lower edge of the plasma inlet 304.

[0062] The top of the cylindrical section 306 can be flat or curved, preferably flat, which can effectively promote the formation of a stable swirling flow of the gas-solid mixture. An outlet 305 is provided at the center of the top flat surface of the cylindrical section 306. In the vertical direction, the top of the outlet 305 is not higher than the lower edge of the plasma inlet 304.

[0063] like Figure 3 and Figure 4 As shown, the powdered solid reactants settle downwards, and the separated non-alkaline tail gas needs to be output from the outlet 305 at the top of the cylindrical section 306 to the tail gas treatment device 4. Since the plasma inlet 304 is also located at the top of the cylindrical section 306, the vicinity of the outlet 305 is a mixture of incompletely settled powdered solid reactants and non-alkaline gases. To prevent powdered solid reactants from mixing into the outlet 305, the outlet 305 extends downwards, not higher than the lower edge of the plasma inlet 304. This prevents solid reactants from being blown into the outlet 305, improving the gas-solid separation effect.

[0064] As an alternative, in the vertical direction, the distance between the top of the outlet 305 and the lower edge of the plasma inlet 304 is 5-20 cm; the diameter of the outlet 305 is 2-15 cm; and in the vertical direction, the distance between the top of the outlet 305 and the top of the cylindrical part 306 is 8-25 cm.

[0065] The distance between the top of the outlet pipe and the lower edge of the plasma inlet 304 is 5-20 cm, allowing for higher solid reactant velocities at higher flow rates, which are then blown into the outlet 305. The diameter of the outlet 305 is comparable to that of the plasma inlet 304 to ensure a relatively consistent gas flow rate at higher flow rates. With these dimensions, the outlet can effectively achieve gas-solid mixture reaction and separation at higher flow rates, while effectively preventing solid reactants from entering the outlet 305.

[0066] As an alternative, the output gas of the exhaust gas treatment device 4 is also connected to the nozzle 21 through a fourth gas path; the discharge port at the bottom of the gas-solid separation chamber is also connected to the fourth gas path.

[0067] The fourth gas path is a channel for the circulation of powdered porous active solid material 302. One end of the fourth gas path is led out from the tail gas treatment device 4. It can recover and reuse the neutral gas after the tail gas treatment device 4, mainly including water vapor. While forming a circulating gas path, it can also be used as an auxiliary gas to promote the plasmaization of sulfur hexafluoride SF6.

[0068] Meanwhile, the fourth gas path is also connected to the discharge port at the bottom of the gas-solid separation chamber, which is the discharge port at the bottom of the conical part 307. It can transport the recyclable solid reactants back to the nozzle 21, so that they can continue to participate in the reaction as porous active solid materials and enter the plasma torch to continue participating in the reaction.

[0069] On the other hand, in order to avoid damage to the plasma torch due to high temperature, the powder hopper 301 is set close to the gas-solid separation chamber, basically at the end of the plasma torch. At this time, the reaction time between the powder and the particles in the plasma torch is short. Through the recycling of the powdered porous active solid material 302 in the fourth gas path, it can re-enter the plasma torch from the nozzle 21 to participate in the reaction for a longer time, making the adsorption and reaction more thorough and further improving the solidification reaction efficiency of the plasma, thereby improving the treatment efficiency of sulfur hexafluoride SF6.

[0070] As an alternative, the powder hopper 301 is positioned above the plasma inlet 304, and a first discharge valve 303 is provided between the powder hopper 301 and the plasma inlet 304 to discharge the powdered porous active solid material to the plasma inlet 304 at a fixed rate and mix and react with the plasma torch.

[0071] like Figure 1As shown, the powder hopper 301 is located above the plasma inlet 304 and connected to the plasma inlet via a pipe. The plasma torch is accessible from the plasma inlet 304. With the powder hopper 301 positioned above it, the powdered porous active solid material 302 can automatically flow out under gravity and react with the plasma torch. No separate drive mechanism is required, resulting in a simple structure, easy implementation, and low cost.

[0072] A first discharge valve 303, which can be a star-shaped discharge valve, is also provided between the powder hopper 301 and the plasma inlet 304. The powdered porous active solid material 302 is discharged to the plasma inlet 304 at a fixed rate and mixed and reacted with the plasma torch.

[0073] The output gas of the exhaust gas treatment device 4 is also connected to the nozzle 21 through a fourth gas path; the gas in the waste bin 309 of the gas-solid separation chamber is connected to the fourth gas path. This allows the output gas of the exhaust gas treatment device 4, as well as the gas mixed in the waste bin 309, to be repeatedly treated, ensuring that harmful gas elements are thoroughly rendered harmless.

[0074] The gas distribution system 1 also includes a controller; the first gas path, the second gas path, the first pressurized gas path and the second pressurized gas path are all equipped with solenoid valves and flow meters; the solenoid valves, flow meters and steam generator 104 are all connected to the controller.

[0075] Setting the position of the solenoid valve can also be used to install flow meters and barometers, which are connected to the controller to monitor relevant data in the corresponding air path, providing a basis for subsequent operations. Specifically, for example... Figure 1 As shown, a first flow meter 105, a second flow meter 106, a third flow meter 107, and a fourth flow meter 108 are respectively installed on the first air path, the second air path, the first pressurized air path, and the second pressurized air path.

[0076] The exhaust gas treatment device 4 is an alkaline scrubbing device; the inlet of the alkaline scrubbing device is connected to the outlet of the gas-solid separation reactor 3, and the outlet of the alkaline scrubbing device is open to the atmosphere.

[0077] The exhaust gas treatment device 4 mainly includes a gas distribution system 1 and an alkaline washing device. The outlet of the gas-solid separation reactor 3 decomposes the gases that have completed the reaction and those that have not participated in the reaction, mainly the exhaust gas generated by the reaction, including oxygen O2, water vapor H2O, and unreacted sulfur-oxygen-fluorine SOF ion / molecule products, into sulfur dioxide SO2, sulfur trioxide SO3, and hydrogen fluoride HF through high temperature.

[0078] Preferably, the alkaline solution in the alkaline washing device can be of the same composition as the aqueous solution of metal oxidation, which is the main component of porous active solid material, and ultimately a metal inorganic salt of the same composition as the solidified material, which can be used as a raw material for industrial concrete.

[0079] As an optional solution, the exhaust gas treatment device 4 is equipped with a mixed solution of sodium hydroxide (NaOH) and calcium hydroxide (Ca(OH)2) with a capacity of 5-15L; the concentration of sodium hydroxide (NaOH) is 0.5-0.8 mol / L, and the concentration of calcium hydroxide (Ca(OH)2) is 0.2-0.5 mol / L; solid particles are also provided in the mixed solution to ensure that the gas-liquid contact time is ≥10 s.

[0080] Since the gaseous products of the sulfur hexafluoride (SF6) reaction are mostly acidic gases, they can be effectively solidified in an alkaline solution to produce inorganic salts and water. The stronger the alkalinity, the better the solidification effect and efficiency of the non-alkaline tail gas, because stronger alkalinity facilitates neutralization reactions. In terms of cost and chemical properties, sodium hydroxide is more alkaline, while calcium hydroxide is less expensive. To balance these two factors, this embodiment uses a mixed solution of sodium hydroxide (NaOH) and calcium hydroxide (Ca(OH)2).

[0081] The concentration of sodium hydroxide (NaOH) is 0.5-0.8 mol / L, and the concentration of calcium hydroxide (Ca(OH)₂) is 0.2-0.5 mol / L. This allows for cost reduction under relatively strong alkalinity. Furthermore, calcium hydroxide (Ca(OH)₂) is slightly soluble in water, and its precipitate can act as solid particles, increasing the viscosity of the solution and extending the gas-liquid contact time. Moreover, the inorganic salt formed from calcium hydroxide (Ca(OH)₂) can react with the more alkaline sodium hydroxide (NaOH), further increasing the reaction rate of calcium hydroxide (Ca(OH)₂), thus maintaining a high overall reaction rate and ensuring the solidification efficiency of non-alkaline tail gas.

[0082] As an alternative, the powdered porous active solid material 302 is a mesoporous material. Mesoporous materials have a hierarchical pore structure containing micron-sized and nano-sized pores, with a porosity of 0.5-0.8 cm⁻¹. 3 / g, the layered pore structure contains mesopores with a diameter of 10nm-40nm.

[0083] The powdered porous active solid material 302 has a diameter of 10-200 μm. This powdered solid material allows for better adsorption and reaction with particles in the plasma torch, resulting in more effective adsorption and reaction.

[0084] If the diameter of the powdered porous active solid material 302 is too small, it is easily dispersed by impact, affecting the mixing reaction of particles in the plasma torch and resulting in a lower adsorption and reaction rate. If the diameter of the powdered porous active solid material 302 is too large, it will settle more quickly, which will also lead to a decrease in adsorption and reaction rate.

[0085] Preferably, the diameter of the powdered solid material is 10-200 μm. It can be 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 170 μm, 180 μm, 190 μm, or 200 μm. Within this size range, the powdered porous active solid material 302 can meet the ion resorption and reaction requirements of the plasma torch without significantly affecting the particle flow rate and subsequent gas-solid separation.

[0086] The porosity of the aforementioned powdered porous active solid material 302 is 0.5-0.8 cm⁻¹. 3 / g, specifically 0.5cm 3 / g, 0.6 cm 3 / g, 0.7 cm 3 / g, 0.8 cm 3 / g. Mesopores exist within the hierarchical porous structure, with diameters ranging from 10nm to 40nm. Specifically, these can be 10nm, 20nm, 30nm, or 40nm.

[0087] Mesoporous materials are a class of materials with a regular pore structure at the nm level. Due to their high specific surface area, adjustable pore size and surface chemical properties, they have good performance in adsorption scenarios, which facilitates reaction with particles in a plasma torch to generate solid compounds to solidify particles that generate harmful byproduct gases.

[0088] Preferably, the porosity is 0.5-0.8 cm. 3 / g, with mesopore diameters of 10nm-40nm. It exhibits good adsorption and reaction efficiency for particulate products of sulfur hexafluoride (SF6) and auxiliary gases.

[0089] As an alternative, the plasma torch includes HF, SO2, and SOF ion / molecular products; the main component of the porous active solid material is a metal oxide; the metal oxide includes at least one of the following: iron oxide, Al2O3, MgO, CaO.

[0090] The aforementioned iron oxides can be ferrous oxide (FeO), ferric oxide (Fe₂O₃), or iron(III) oxide (Fe₃O₄). Since the harmful byproduct gases produced in the plasma torch of sulfur hexafluoride (SF₆) are mainly F and S elements, and the oxides and hydrides of these two elements are acidic, they can react with metal oxides to form solid inorganic metal salts. Therefore, using the aforementioned iron oxides, aluminum oxide (Al₂O₃), magnesium oxide (MgO), and calcium oxide (CaO) can all achieve the curing function.

[0091] Specifically, in one alternative, a combination of ferrous oxide (FeO), aluminum oxide (Al₂O₃), magnesium oxide (MgO), and calcium oxide (CaO) can be used. This combination has lower requirements for raw materials, resulting in lower manufacturing costs for the porous active solid material. In another alternative, a combination of aluminum oxide (Al₂O₃), magnesium oxide (MgO), and calcium oxide (CaO) can be used. Because ferrous oxide (FeO) is absent, the other metal oxides exhibit better reactivity than FeO, resulting in better adsorption performance compared to the first option.

[0092] Another alternative is to use a combination of magnesium oxide (MgO) and calcium oxide (CaO). This approach not only further increases the reaction rate but also takes into account raw material costs. Another alternative is to use either calcium oxide (CaO) or magnesium oxide (MgO) alone. This approach offers the highest reaction rate, thereby allowing for a further increase in the processing flow rate of sulfur hexafluoride (SF6).

[0093] As an alternative, the metal oxide is calcium oxide (CaO) and / or magnesium oxide (MgO).

[0094] Because calcium (Ca) and magnesium (Mg) have relatively stable fluorides and sulfides, especially calcium (Ca), whose fluorides and sulfides are relatively stable, they are more suitable as porous active solid materials to participate in the reaction and effectively solidify fluorine (F) and sulfur (S).

[0095] As an alternative, the plasma generator 2 includes a nozzle 21, a waveguide device, and a discharge tube; the waveguide device is a rectangular waveguide 204; the rectangular waveguide 204 is provided with mounting holes that match the cross-sectional shape of the discharge tube; the nozzle 21 is a multi-gas channel nozzle 21; the multiple gas channels of the nozzle 21 include a first channel 201 for transmitting auxiliary gas, a second channel 202 for transmitting SF6, and a third channel 203 for recovering a portion of the powdered porous active solid material; the discharge tube is a double-layer cylindrical tube, which includes an outer tube 206 and an inner tube 205. The outer tube 206 is fixed to the waveguide device, and the nozzle 21 is disposed at one end of the inner tube 205 to accommodate the plasma torch in the inner tube 205.

[0096] The plasma generator 2 includes a nozzle 21, a waveguide device, and a discharge tube. The nozzle 21 is connected to the gas distribution system 1. The nozzle 21 is located at one end of the discharge tube where the waveguide device is installed, and the other end of the discharge tube is connected to the plasma inlet 304. The nozzle 21 is used to eject the mixed gas into the effective range of the waveguide device and continuously eject it to the plasma inlet 304. The discharge tube is a straight tube, and the position of the nozzle 21 is flush with the position of the plasma inlet 304 on the horizontal plane. The waveguide device is used to ionize and heat the mixed gas to obtain a plasma torch. The ejection direction of the nozzle 21 is towards the plasma inlet 304 of the gas-solid separation reactor 3.

[0097] Plasma generator 2 is mainly used for microwave plasma conversion of sulfur hexafluoride (SF6) and auxiliary gas to generate a plasma torch. There are many ways to excite plasma, such as direct current discharge, radio frequency plasma, microwave plasma, and pulsed discharge plasma. To ensure the decomposition efficiency of SF6, this embodiment uses microwave plasma for decomposition, which can completely decompose SF6.

[0098] The aforementioned waveguide device is used to transmit microwaves to nozzle 21 to perform plasma conversion on the ejected sulfur hexafluoride (SF6) and auxiliary gas mixture. That is, nozzle 21 needs to be connected to the gas distribution system 1 and configured to eject the mixed gas into the effective range of the waveguide device. While ejecting the mixed gas, nozzle 21 is simultaneously plasmaized by the microwaves from the waveguide device, forming a plasma torch, such as... Figure 1 As shown.

[0099] The plasma generator 2 described above can utilize a hardware structure to configure the nozzle 21 and waveguide device, ensuring that the nozzle 21 is within the effective range of the waveguide device, thereby guaranteeing effective ionization of the mixed gas. In this embodiment, a glass discharge tube can be used as the aforementioned hardware structure. This not only allows for effective observation of the internal reaction but also enables the concentration of the mixed gas ejected from the nozzle 21, resulting in a more focused plasma torch and higher ionization efficiency.

[0100] Nozzle 21 is disposed at the inlet of the discharge tube, and the waveguide device is mounted on the glass tube near the inlet, thereby effectively placing nozzle 21 within the effective area of ​​the waveguide device. Preferably, in this embodiment, the edge of the effective area of ​​the waveguide device corresponds to the placement position of nozzle 21, that is, nozzle 21 is placed at the edge of the effective area of ​​the waveguide device. This allows the gas ejected from nozzle 21 to pass through a larger microwave action range, thereby improving ionization efficiency and degree, and ensuring complete ionization of the mixed gas.

[0101] The nozzle 21 ejects plasma towards the plasma inlet 304 of the gas-solid separation reactor 3, allowing plasma particles to be sprayed onto the plasma inlet 304 to mix and react with the powdered porous active solid material 302 released from the powder silo 301, thereby improving adsorption and reaction efficiency. Furthermore, the powdered porous active solid material 302 is heated by a plasma torch, raising the reaction temperature between the plasma torch's molecules / ions and the powdered porous active solid material 302, which can further increase the reaction rate.

[0102] One end of the discharge tube is also the input port of the plasma generator 2. To prevent harmful byproduct gases from escaping from the plasma torch, the discharge tube is connected to the plasma inlet 304 of the gas-solid separation reactor 3, forming a closed reaction space. For example, as... Figure 1 As shown, the discharge tube is a horizontally arranged glass tube with a nozzle 21 installed at the left end and the right end connected to the plasma inlet 304, forming a closed plasma generation space and reaction space.

[0103] The aforementioned discharge tube is a straight tube, which not only facilitates the ejection and extension of the plasma torch within it, but also facilitates its connection to the plasma inlet 304. This allows the plasma torch to effectively reach the release port of the powder hopper 301 and react effectively with the powdered porous active solid material 302.

[0104] The nozzle 21 is positioned flush with the plasma inlet 304 on the horizontal plane. This is to ensure that the nozzle has an initial horizontal velocity when entering the gas-solid separation chamber from the plasma inlet 304, thus preventing turbulence between the gas and powder in the gas-solid separation chamber and reducing the separation efficiency.

[0105] like Figures 2 to 3 As shown, when viewed from above, the plasma inlet 304 of the gas-solid separation chamber is tangent to the cylindrical section 306. This allows the gas-liquid mixture to enter the cylindrical section 306 and form a stable swirling flow within it, thereby increasing the gas flow path, extending the gas-solid separation time, and improving the gas-solid separation effect.

[0106] The gas-solid separation chamber is also equipped with an outlet 305, through which the gas after reaction and separation can be transmitted to the exhaust gas treatment device 4 for final harmless treatment.

[0107] The discharge tube is a cylindrical tube, and the interior of the discharge tube is used to house the plasma torch; the length of the cylindrical tube is not less than half the length of the plasma torch, and the length of the plasma torch is the dimension of the flame beam of the plasma torch along the ejection direction.

[0108] like Figure 1As shown, the discharge tube is a cylindrical tube, preferably a columnar tube. The cylindrical tube can form a longer converging space along the ejection direction, which allows the mixed gas to be fully mixed and ionized inside, further improving the ionization effect of the mixed gas.

[0109] In order to effectively beam the plasma torch and improve the reaction degree so that the plasma torch can effectively reach the position of the powdered porous active solid material 302 in the powder hopper 301, the length of the columnar tube is set to at least half the length of the plasma torch.

[0110] like Figure 1 As shown, the rectangular waveguide 204 is a hollow metal tube with a rectangular cross-section. Low-loss transmission is achieved through the reflection of electromagnetic waves within the cavity. It features low transmission loss, high power capacity, and good shielding. Its high-power microwave transmission capability offers even better performance in plasma ionization scenarios.

[0111] The rectangular waveguide 204 is installed at the inlet of the glass tube, and the entire interior of its metal tube is within the effective range. The nozzle 21 is set flush with the upper wall of the rectangular waveguide 204, so that the mixed gas ejected by the nozzle 21 has a longer ionization range within the effective range, thereby improving the degree of ionization and efficiency.

[0112] The nozzle 21 described above is a multi-channel nozzle 21, with multiple gas channels independently ejecting the mixed gas. The nozzle 21 is connected to the gas distribution system 1, where sulfur hexafluoride (SF6) and auxiliary gas can be mixed and pressurized in a specific ratio. Alternatively, a fixed ratio of SF6 and auxiliary gas can be pressurized in the gas distribution system 1 and transmitted to the nozzle 21 for simultaneous mixing during ejection. The first method places greater complexity on the gas distribution system 1, and incomplete mixing may occur during the gas mixing process, affecting the ionization effect.

[0113] Therefore, in this embodiment, sulfur hexafluoride (SF6) and auxiliary gas are pressurized and mixed at the same time as they are ejected from nozzle 21. The pressurized gas has higher energy and can be mixed more evenly at the same time as it is ejected, thereby improving the ionization effect.

[0114] Nozzle 21 is configured as a multi-gas-channel nozzle 21, with multiple independent gas channels ejecting a single sulfur hexafluoride (SF6) or auxiliary gas. For example... Figure 1 As shown, nozzle 21 has three gas channels, each including at least one independent channel. The middle second channel 202 is a sulfur hexafluoride (SF6) gas channel that sprays SF6. The other two are the first channel 201 and the third channel 203. The first channel 201 is an auxiliary gas channel that sprays auxiliary gas. The third channel 203 is connected to the outlet 305 of the exhaust gas treatment device 4.

[0115] The discharge tube is a double-layered cylindrical tube, which includes an outer tube 206 and an inner tube 205. A waveguide device is disposed on the outer tube 206, and a nozzle 21 is disposed at one end of the inner tube 205 to accommodate the plasma torch in the inner tube 205.

[0116] Because there is a significant size difference between the single-layer discharge tube and the nozzle 21, gas backflow can easily occur near the nozzle 21, affecting the ionization effect of the mixed gas. To address this, the discharge tube can be a double-layer cylindrical tube, comprising an outer tube 206 and an inner tube 205. The waveguide device is mounted on the outer tube 206 to meet the installation requirements. The nozzle 21 is located at one end of the inner tube 205 to house the plasma torch. The size of the inner tube 205 is closer to that of the nozzle 21, which eliminates gas backflow, allowing the gas ejected from the nozzle 21 to continue mixing and ionizing, thus improving the ionization effect. Simultaneously, it also provides a better jetting effect on the plasma torch.

[0117] It should be noted that similar multi-layered tubes, such as three-layered tubes, four-layered tubes, etc., can also achieve the same technical effect. The channel between the inner tube 205 and the outer tube 206 can prevent the backflow of particles from the plasma torch.

[0118] The inner tube 205 of the double-layer discharge tube confines the plasma to enhance the concentration of microwave energy, while the outer tube 206 isolates the high temperature from the waveguide. This maintains the high enthalpy stability of the plasma to improve degradation efficiency and avoids resonant frequency drift caused by waveguide thermal deformation.

[0119] As an alternative, the rectangular waveguide 204 has a power of 1-50 kW; it can meet the requirements of atmospheric pressure microwave plasma ionization of large flow rates of sulfur hexafluoride SF6, so as to ensure the complete reaction with the powdered porous active solid material 302 and improve the degradation effect.

[0120] The size of a plasma torch is generally related to the flow rate and waveguide power. To meet the demand for higher flow rates, the waveguide power is increased. The ionization process of the auxiliary gas and sulfur hexafluoride (SF6) in the plasma torch requires a certain amount of time, which means that the particles at different positions in the plasma torch are different. Under the action of the rectangular waveguide 204 mentioned above, the length of the plasma torch formed under different pressures is 15-75 cm, which can ensure that the ionization process of the auxiliary gas and sulfur hexafluoride (SF6) can be carried out effectively and completely, thereby ensuring the efficiency of subsequent reactions.

[0121] The inner tube 205 can withstand temperatures ≥1500℃. While the plasma torch can reach temperatures of several thousand to tens of thousands of degrees, the discharge tube is not in direct contact with the plasma torch, but the distance is not far. To prevent melting, the inner tube 205 is made of high-temperature resistant glass, capable of withstanding temperatures of at least 1500℃. The inner tube 205 has a diameter of 2-7cm, comparable to the size of the nozzle 21, and a length of 4-25cm, not less than the maximum size of the plasma torch. The outer tube 206 has a diameter of 3-20cm and a length of 20-120cm. The diameter of the outer tube 206 is larger than that of the inner tube 205. Radially, the distance between the outer tube 206 and the inner tube 205 is 1-10cm.

[0122] The dimensions of the double-layered columnar tube in the ejection direction are 20-120 cm, that is, the length of the outer tube 206 is 20-120 cm, specifically 20 cm, 30 cm, 40 cm, 50 cm, 60 cm, 70 cm, 80 cm, 90 cm, 100 cm, 110 cm, 120 cm; the diameter of the outer tube 206 Φ=3-20 cm, specifically 3 cm, 4 cm, 5 cm, 6 cm, 7 cm, 8 cm, 9 cm, 10 cm, 11 cm, 12 cm, 13 cm, 14 cm, 15 cm, 16 cm, 17 cm, 18 cm, 19 cm, 20 cm.

[0123] The axial dimension of the inner tube 205 is 4-25 cm, specifically 4cm, 5cm, 6cm, 7cm, 8cm, 9cm, 10cm, 11cm, 12cm, 13cm, 14cm, 15cm, 16cm, 17cm, 18cm, 19cm, 20cm, 21cm, 22cm, 23cm, 24cm, and 25cm. The diameter Φ is 2-7 cm, specifically 2cm, 3cm, 4cm, 5cm, 6cm, and 7cm.

[0124] It should be noted that the length and diameter of the inner tube 205 are both smaller than the length and diameter of the outer tube 206.

[0125] In specific implementation, such as Figure 1 As shown, the single-channel diameter of nozzle 21 is 0.8-3cm, specifically 0.8cm, 1cm, 1.6cm, 2cm, 2.4cm, 3cm, etc. Located at the left end of the double-layer discharge tube; the discharge tube is a double-layer cylindrical structure made of quartz glass, with an outer layer Φ3-20cm and a length of 20-120cm, and an inner layer Φ2-7cm and a length of 4-25cm, resistant to high temperatures ≥1500℃. The outer tube 206 of the discharge tube is connected to the gas-solid separation reactor 3. The gas-solid separation reactor 3 has a built-in thermocouple that monitors the reactor temperature in real time at 800-1400℃.

[0126] As an optional solution, the gas distribution system 1 includes a sulfur hexafluoride (SF6) gas source 102, an auxiliary gas source 101, a steam generator 104, and an air compressor 103; the first gas path of the auxiliary gas source is connected to the first channel 201 of the nozzle 21; the second gas path of the SF6 gas source 102 is connected to the first pressurized gas path of the air compressor 103, and the second gas path of the SF6 gas source 102 is also connected to the second channel 202 of the nozzle 21; the third gas path of the steam generator 104 is connected to the second pressurized gas path of the air compressor 103; both the first pressurized gas path and the second pressurized gas path are connected to the nozzle 21.

[0127] like Figure 1 As shown, the sulfur hexafluoride (SF6) gas source 102 can be an SF6 gas bag, which can be conveniently collected from power equipment for processing. The components of the entire device are relatively simple, and the overall device is very convenient compared to some large-scale centralized SF6 processing equipment. It can be moved and used to process SF6 as needed.

[0128] The third gas path of the steam generator 104 is connected to the air compressor 103 via the second pressurized gas path. This allows the air compressor 103 to pressurize the steam or directly input the pressurized steam into the nozzle 21. The second pressurized gas path is also combined with the second gas path of the sulfur hexafluoride (SF6) gas source 102 to form an output gas path, where they are mixed into a mixed gas. Of course, this output gas path can also refer to a simple combination of the first and second gas paths, meaning that the first and second gas paths only overlap in their paths, and the internal gases remain independent.

[0129] The output air path is also connected to the air compressor 103 through the first pressurized air path. The output air path can also be connected to the air compressor 103, which can provide compensating pressurization or secondary pressure regulation. This further improves the stability of air pressure control.

[0130] The auxiliary gases for the plasma degradation of sulfur hexafluoride (SF6) can include reactive gases, inert diluent gases, and mixed gases. Reactive gases can include oxygen (O2), hydrogen (H2), and water vapor (H2O). Inert diluent gases can include argon (Ar) and nitrogen (N2). Mixed gases are mixtures of reactive and inert diluent gases, such as a mixture of oxygen (O2) and nitrogen (N2), or a mixture of water vapor (H2O) and argon (Ar).

[0131] Water vapor, as an auxiliary gas, promotes the complete mineralization of sulfur hexafluoride (SF6). Through the generation of hydroxyl radicals and hydrogen atoms, water vapor drives the decomposition of SF6 into acidic sulfur dioxide (SO2), hydrogen fluoride (HF), and a small amount of sulfur trioxide (SO3), preventing the accumulation of toxic intermediates (such as sulfur tetrafluoride (SF4) and thionyl fluoride (SOF2)). The final products, sulfur dioxide (SO2) and hydrogen fluoride (HF), can be absorbed by alkaline solutions, such as calcium hydroxide (Ca(OH)2), and neutralized to form calcium sulfate (CaSO4) and calcium fluoride (CaF2).

[0132] It can also enhance plasma activity. Water vapor dissociates in the plasma to generate active species, significantly improving oxidation capacity. The oxidation potential of hydroxyl radicals (2.8 V) is much higher than that of oxygen (O2), which can efficiently attack carbon-fluorine bonds (CF) and sulfur-fluorine bonds (SF). Moreover, when water vapor (H2O) mixes with oxygen (O2), the active oxygen species in the plasma (oxygen radicals (O·) and ozone (O3)) work synergistically with hydroxyl radicals to accelerate the decomposition of sulfur hexafluoride (SF6).

[0133] It can also inhibit the formation of toxic byproducts and reduce sulfur tetrafluoride (SF4) and thionyl fluoride (SOF2). Water vapor, by providing hydrogen atoms, blocks the decomposition chain reaction of sulfur hexafluoride (SF6) and low-fluoride sulfur (X-sulfur fluoride) in the process. x The generation of sulfur (x=1~4) and the introduction of water vapor H2O can prevent the generation of elemental sulfur (S8) (common in pure argon (Ar) or nitrogen (N2) plasma), thus avoiding sulfur deposition.

[0134] Water vapor can also optimize energy utilization efficiency. The presence of water vapor can reduce plasma breakdown voltage (because the ionization energy of water vapor H2O is lower than that of sulfur hexafluoride SF6), thus reducing energy consumption. The generated hydrogen fluoride HF can be treated through subsequent absorption, which, compared to the direct generation of corrosive intermediates such as sulfur tetrafluoride SF4, can reduce corrosion of the reactor and extend equipment life.

[0135] Finally, water vapor is environmentally friendly and economical. The sulfur dioxide (SO2) and hydrogen fluoride (HF) produced by plasma decomposition of water vapor with sulfur hexafluoride (SF6) are conventional industrial waste gases that can be easily neutralized with lime slurry (producing gypsum and calcium fluoride), resulting in no secondary pollution. Water vapor is inexpensive and readily available, requiring no complex gas pretreatment.

[0136] Example 2

[0137] This embodiment provides an SF6 waste gas degradation device based on gas-solid reaction enhancement, comprising a gas distribution system 1, a plasma generator 2, a gas-solid separation reactor 3, and a tail gas treatment device 4.

[0138] like Figure 1As shown, the gas distribution system 1 includes an auxiliary gas source 101, a sulfur hexafluoride (SF6) gas source 102, an air compressor 103, and a steam generator 104. The auxiliary gas source 101 assists the degradation reaction through the first channel 201 of the nozzle 21. The SF6 gas source 102, the air compressor 103, and the steam generator 104 distribute the reaction gases (SF6 gas / dilution gas / active gas) through the second channel 202 of the nozzle 21. The SF6 gas source 102 branch controls the SF6 intake volume through a second flow meter 106. The air compressor 103 is equipped with a third flow meter 107 and a fourth flow meter 108. The steam generator 104 can output saturated steam at 100°C by heating or output room temperature steam by ultrasonic means. The auxiliary gas source 101 branch controls the auxiliary gas intake volume through a first flow meter 105.

[0139] The plasma generator 2 includes a rectangular waveguide 204, a nozzle 21, and a double-layered discharge tube. The rectangular waveguide 204 is a BJ22 or BJ26 waveguide, outputting adjustable microwaves of 2.45 GHz and 1-50 kW. These microwaves excite a plasma torch via a three-channel nozzle 21 on the left side. The plasma torch is 15-75 cm long, specifically 15cm, 20cm, 25cm, 30cm, 35cm, 40cm, 45cm, 50cm, 55cm, 60cm, 65cm, 70cm, and 75cm. The nozzle 21 has a single-channel diameter of 0.8-5cm, preferably 2cm, located at the left end of the discharge tube. The discharge tube is a double-layered cylindrical structure made of quartz glass. The outer tube 206 has a diameter Φ of 10cm and a length of 70cm, while the inner tube 205 has a diameter Φ of 7cm and a length of 15cm, and is heat-resistant to ≥1500℃. The outer tube 206 is connected to the gas-solid separation reactor 3. The reactor is equipped with built-in thermocouples to monitor the reactor temperature in real time, ranging from 800 to 1400℃.

[0140] The gas-solid separation reactor 3 is a cyclone structure, including a powder hopper 301, a plasma inlet 304, a gas outlet 305, a cylindrical section 306, a conical section 307, and a waste hopper 309. The powder hopper 301 is located above the plasma inlet 304 and is filled with one or more powdered porous active solid materials 302, such as CaO, MgO, Al2O3, or Fe2O3, with a pore size of Φ10-200μm. The powdered porous active solid material 302 has mesopores with a pore size of 10-40 nm, a porosity of 0.5-0.8 cm3 / g, and a mass ratio of 1:1. The input of the powdered porous active solid material 302 is controlled by a first discharge valve 303. Figure 1As shown, the diameter Φ of the plasma inlet 304 is 3-20 cm, specifically 3cm, 4cm, 5cm, 6cm, 7cm, 8cm, 9cm, 10cm, 11cm, 12cm, 13cm, 14cm, 15cm, 16cm, 17cm, 18cm, 19cm, and 20cm.

[0141] The plasma inlet 304 can be the same size as the outer tube 206, preferably with a diameter of Φ10 cm, and is located at the top side of the cylindrical section 306, connected to the outer tube 206 of the discharge tube. The cylindrical section 306 is a cylindrical structure with a diameter of 5-30 cm, which can be 5cm, 10cm, 15cm, 20cm, 25cm, 30cm, preferably 20cm. The vertical length of the cylindrical section 306 is 10-60 cm, which can be 10cm, 20cm, 30cm, 40cm, 50cm, 60cm, preferably 40cm.

[0142] The lower end of the cylindrical portion 306 is connected to the upper end of the conical portion 307. The vertical length of the conical portion 307 is 15-80 cm, and can be 15cm, 20cm, 25cm, 30cm, 35cm, 40cm, 45cm, 50cm, 55cm, 60cm, 65cm, 70cm, 75cm, or 80cm, preferably 60cm. The bottom diameter is 2-6 cm, and can be 2cm, 3cm, 4cm, 5cm, or 6cm, preferably 5cm. The lower end of the conical portion 307 is connected to the third channel 203 of the nozzle 21 and the waste bin 309 via branch pipes.

[0143] The waste bin 309 is a cylindrical structure with a diameter of 4-25 cm and a length of 6-30 cm. The diameter can be 4cm, 5cm, 6cm, 7cm, 8cm, 9cm, 10cm, 11cm, 12cm, 13cm, 14cm, 15cm, 16cm, 17cm, 18cm, 19cm, 20cm, 21cm, 22cm, 23cm, 24cm, or 25cm, preferably 15cm. The vertical length can be 6cm, 7cm, 8cm, 9cm, 10cm, 11cm, 12cm, 13cm, 14cm, 15cm, 16cm, 17cm, 18cm, 19cm, 20cm, 21cm, 22cm, 23cm, 24cm, 25cm, 26cm, 27cm, 28cm, 29cm, or 30cm, preferably 20cm.

[0144] The waste bin 309 is controlled by the second discharge valve 308 to discharge the solid material deposited in the conical part 307 into the waste bin 309. The diameter Φ of the outlet 305 is 2-15 cm, specifically 2cm, 3cm, 4cm, 5cm, 6cm, 7cm, 8cm, 9cm, 10cm, 11cm, 12cm, 13cm, 14cm, 15cm, preferably 8cm. It is inserted into the interior of the cylindrical part 306 from the center of the top of the cylindrical part 306 to a depth of 8-25cm, specifically 8cm, 9cm, 10cm, 11cm, 12cm, 13cm, 14cm, 15cm, 16cm, 17cm, 18cm, 19cm, 20cm, 21cm, 22cm, 23cm, 24cm, 25cm, preferably 15cm. The insertion depth of the outlet 305 can be slightly lower than the bottom of the plasma inlet 304, and the other end of the outlet 305 leads to the exhaust gas treatment device 4.

[0145] The exhaust gas treatment device 4 contains a 5-15L mixed solution of NaOH and Ca(OH)2, specifically 5L, 10L, or 15L, preferably 10L. The NaOH concentration is 0.5-0.8 mol / L, specifically 0.5mol / L, 0.6mol / L, 0.7mol / L, or 0.8mol / L, preferably 0.6mol / L. The Ca(OH)2 concentration is 0.2-0.5 mol / L, 0.2mol / L, 0.3mol / L, 0.4mol / L, or 0.5mol / L, preferably 0.3mol / L. Some solid particles are placed in the solution to disperse the gas in the alkaline solution. The gas-liquid contact time is ≥10 s, preferably ≥30 s. The exhaust gas outlet integrates a pH sensor (range 0-14, accuracy ±0.1), one end of which is connected to the third channel 203 of nozzle 21 via a fourth gas path, and the other end is directly discharged into the atmosphere.

[0146] This embodiment utilizes a microwave plasma torch to degrade sulfur hexafluoride (SF6) gas. The degradation products enter the expanded structure at the end of the microwave gas-solid separation reactor 3 along with the plasma. Under the action of the plasma, the active solid material is heated and undergoes a spontaneous reaction to generate solid products containing harmful substances, achieving efficient degradation of SF6 and effective suppression of harmful byproducts. The processing flow rate can reach 1.5-160 L / h, the SF6 degradation efficiency is ≥99.9%, and the amount of harmful byproducts (such as SO2, HF, etc.) generated is ≤0.1%.

[0147] Example 3

[0148] Figure 4 This is a flowchart of an embodiment of the present invention of an SF6 waste gas degradation method based on gas-solid reaction enhancement, as shown below. Figure 4As shown, according to another aspect of the present invention, a method for degrading SF6 waste gas based on gas-solid reaction enhancement is also provided, comprising the following steps:

[0149] In step S401, sulfur hexafluoride (SF6) is mixed with auxiliary gas through the gas mixing system 1 and then input into the plasma generator 2.

[0150] In step S402, sulfur hexafluoride (SF6) is mixed with an auxiliary gas by a plasma generator 2, ejected in a predetermined ejection direction, and ionized to form a plasma torch.

[0151] Step S403 involves adding powdered porous active solid material to a plasma torch, where it is adsorbed and undergoes a chemical reaction to generate powdered solid reactants and non-alkaline tail gas. The solid reactants and non-alkaline tail gas are then separated in a gas-solid separation chamber located in the direction of plasma torch ejection. The gas-solid separation reactor 3 includes a plasma inlet 304 and a gas-solid separation chamber. A powder hopper 301 is located at the plasma inlet 304, storing powdered porous active solid material. The gas-solid separation chamber is vertically positioned with an opening at its top connected to the plasma inlet 304. An outlet 305 is located at the top of the gas-solid separation chamber, and a discharge port is located at the bottom.

[0152] In step S404, the non-alkaline exhaust gas is transferred to the exhaust gas treatment device 4, where it undergoes a secondary reaction in the alkaline solution within the device to achieve harmless treatment.

[0153] The aforementioned SF6 waste gas degradation method based on gas-solid reaction enhancement first solidifies the particles related to harmful byproduct gases in the plasma torch through powder mixing, and then performs harmless treatment in conjunction with the tail gas treatment device 4. Compared with existing technologies that only use alkaline scrubbing devices, this method greatly improves the treatment efficiency and suppression effect of harmful byproducts, thereby enabling higher flow rate ion treatment. Compared with the existing maximum SF6 treatment flow rate of 40L / h, this invention significantly increases the treatment flow rate while maintaining the same treatment efficiency, achieving a several-fold increase and solving the problem of low treatment flow rate in existing technologies for SF6 degradation.

[0154] The free energy changes before and after the chemical reaction between the main components of the porous active solid material and the relevant ions of sulfur (S) and fluorine (F) elements in the plasma torch. satisfy: In other words, the main components of the powdered porous active solid material 302 form a chemical reaction system with molecules / ions in the plasma torch. This system can spontaneously react at temperatures ranging from 0-4000K, and the products tend to exist in a solid state. Combined with the properties of porous materials, this allows for the rapid and efficient solidification of ions that would otherwise form harmful byproducts when adsorbing molecules / ions from the plasma torch. This not only improves processing efficiency but also increases the processing flow rate. Furthermore, it prevents harmful byproduct ions from easily undergoing secondary reactions to generate harmful gaseous byproducts when forming gaseous products. This further improves the treatment efficiency of sulfur hexafluoride (SF6).

[0155] Finally, the exhaust gas is connected to the output port of the gas-solid separation reactor 3 via the exhaust gas treatment device 4, which contains an alkaline solution. Since the harmful byproduct gases are generally acidic gases of fluorine oxides and sulfur oxides, the alkaline solution can fully react with the small amount of gas that has not reacted with the powdered porous active solid material 302, thus achieving harmless treatment.

[0156] As an alternative, the mixed gas is ejected in a predetermined ejection direction by the plasma generator 2 and ionized to form a plasma torch. This includes: ionizing the ejected mixed gas through a waveguide device to form a plasma torch; if the end of the plasma torch does not reach the discharge position of the powder hopper 301, increasing the output pressure of the air compressor 103 and increasing the microwave power of the microwave source of the waveguide device to lengthen the plasma torch so that it can reach the discharge position of the powder hopper 301; or, if the plasma torch reaches the inside of the gas-solid separation chamber, decreasing the output pressure of the air compressor 103 and decreasing the microwave power of the microwave source to shorten the plasma torch.

[0157] It should be noted that, in addition to degrading sulfur hexafluoride (SF6), the plasma torch can also heat the powdered porous active solid material 302 at high temperatures to increase the reaction rate. Therefore, the plasma torch needs to be able to reach the powdered porous active solid material 302, which is also the outlet location of the powder hopper 301.

[0158] When the plasma torch is short, it can be extended by pressurizing it with an air compressor 103. In order to match the increased gas flow after pressurization, the microwave source of the waveguide device also needs to increase its microwave power accordingly to ensure the efficiency and extent of plasma degradation.

[0159] Plasma sustaining power P maintain To meet the requirements for ionization and excitation, its relationship with gas pressure p can be:

[0160] P maintain ∝ne ⋅E collision ∝p⋅f(E / p), where n e E is the electron density. collision E represents the collision energy loss, E represents the electric field strength, and f() is the plasma characteristic function of sulfur hexafluoride (SF6) and water vapor, used to describe the effect of the ratio of electric field strength E to gas pressure p on plasma characteristics.

[0161] When the gas pressure increases, if the power remains unchanged while the gas pressure is adjusted, it may lead to plasma instability and insufficient electron energy. The power needs to be increased simultaneously to compensate for the higher collision energy loss and maintain ionization balance.

[0162] Conversely, when the plasma torch reaches the interior of the gas-solid separation chamber, the output pressure is reduced by controlling the air compressor 103. When the air pressure decreases, the microwave power of the microwave source is reduced to shorten the plasma torch and maintain ionization balance.

[0163] As an alternative approach, a powdered porous active solid material is added to the plasma torch to adsorb and react chemically with the plasma torch, generating powdered solid reactants and non-alkaline tail gas. This includes: adsorbing and reacting SOF ion / molecular products from the plasma torch with the powdered porous active solid material, whose main component is metal oxide, to generate powdered solid inorganic salts and corresponding tail gas, which includes oxygen (O2) and water vapor (H2O); unreacted SOF ion / molecular products are decomposed at high temperature into sulfur dioxide (SO2), sulfur trioxide (SO3), and hydrogen fluoride (HF); sulfur dioxide (SO2), sulfur trioxide (SO3), and hydrogen fluoride (HF) are mixed with the tail gas to form non-alkaline tail gas, and the mixed powdered solid inorganic salts are carried into the gas-solid separation chamber by the gas flow.

[0164] The sulfur-oxygen-fluorine (SOF) ionic / molecular products are numerous, and when reacting with metal oxides, they generate corresponding inorganic metal salts. The final intermediate product gases are mainly oxygen (O2) and water vapor (H2O). Although hydrogen fluoride (HF) is also a gas, it can further participate in the reaction to generate calcium fluoride (CaF2) and water (H2O). Even if some does not participate in the reaction, it can ultimately be rendered harmless by the alkaline solution in the tail gas treatment device 4.

[0165] As an optional solution, before the SF6 and auxiliary gas are mixed through the gas distribution system 1 and input into the plasma generator 2, the method further includes: inputting the auxiliary gas and opening the powder silo 301, forming a gas circulation through the gas-solid separation chamber and the fourth gas path connected to the outlet of the gas-solid separation chamber, and then closing the powder silo 301; after separating the solid reactants and non-alkaline tail gas in the gas-solid separation chamber in the direction of plasma torch ejection, the method further includes: recovering the separated solid reactants to the waste silo 309, and opening the powder silo 301 for replenishment to continue the reaction with the plasma torch; after transmitting the non-alkaline tail gas to the tail gas treatment device 4, and achieving harmless treatment through secondary reaction in the alkaline solution in the tail gas treatment device 4, the method further includes: transmitting the output gas of the tail gas treatment device 4 to the nozzle 21 as an auxiliary gas for plasma reaction.

[0166] Non-alkaline tail gas and solid reactants are separated in the gas-solid separation chamber. However, due to the short reaction time, the solid reactants often do not react completely, and direct disposal is wasteful. Therefore, the solid reactants in the waste bin 309 can be transferred to the discharge tube to react further with the plasma torch. After being recycled for a period of time, they can be discarded or treated as industrial concrete.

[0167] It should be noted that in this embodiment, the waste bin 309 is connected to the fourth gas path. The fourth gas path is the channel connecting the outlet 305 of the exhaust gas treatment device 4 to the nozzle 21. The powdered solid reactant can be transported to the nozzle 21 by means of the circulating airflow in the fourth gas path and react fully with the plasma torch.

[0168] In use, SF6 and auxiliary gas are mixed through the gas distribution system 1 and input into the plasma generator 2. Before the auxiliary gas is input, the powder silo 301 is opened, and a gas circulation is formed through the gas-solid separation chamber and the fourth gas path connected to the outlet of the gas-solid separation chamber. The entire interior of the device is filled with powdered porous active solid material 302. Then the powder silo 301 is closed, and the gas distribution system 1 is opened again to introduce sulfur hexafluoride SF6 for reaction. At this time, the outlet of the conical part 307 will not enter the waste silo 309.

[0169] After a period of cyclic reaction, the waste bin 309 is opened, and the solid reactants are placed into it. Simultaneously, the powder bin 301 is opened, and new powdered porous active solid material 302 is added to the reaction system at the same rate for cyclic reaction. After recovering a portion of the solid reactants, the waste bin 309 is closed again. At this point, the solid reactants at the outlet will enter the fourth gas path and recirculate to nozzle 21, entering the plasma torch for further reaction.

[0170] The alkaline solution in the alkaline washing device reacts with the acidic gases in the non-alkaline tail gas to produce water and inorganic salts. The acidic gases include hydrogen fluoride (HF), sulfur trioxide (SO3), and sulfur dioxide (SO2). The alkaline solution also dissolves the neutral gases in the non-alkaline tail gas, which include oxygen (O2) and water vapor (H2O). The inorganic salts are used to manufacture industrial concrete.

[0171] The aforementioned non-alkaline exhaust gas includes neutral oxygen (O2) and water vapor (H2O) which dissolve the acidic hydrogen fluoride (HF), sulfur trioxide (SO3), and sulfur dioxide (SO2) in the alkaline solution to produce water and inorganic salts, thus completing the solidification of sulfur (S) and fluorine (F) elements that have not reacted with the porous active solid material.

[0172] The resulting inorganic salts can also be used in the manufacture of industrial concrete. For this purpose, the metal cations in the alkaline solution can be kept consistent with the metal cations in the metal oxide, allowing the final inorganic metal salts to aggregate and be used together as raw materials for industrial concrete. Further recycling of the harmless treatment products avoids resource waste, improves the system's energy-saving and environmental performance, and generates certain economic benefits.

[0173] Example 4

[0174] Based on the SF6 waste gas degradation device based on gas-solid reaction enhancement in Example 2, a harmless treatment method for degrading sulfur hexafluoride (SF6) waste gas under normal pressure microwave plasma is also provided, including the following steps.

[0175] The mixed gas and auxiliary gas are mixed through the gas distribution system 1 and input into the atmospheric pressure microwave plasma generator 2. The plasma torch is formed by ionization and degrades sulfur hexafluoride (SF6). The powdered porous active solid material 302 in the discharge tube adsorbs and reacts with the plasma torch to generate harmless solid products and non-alkaline tail gas. The non-alkaline tail gas and powdered solid reactants are separated by the cyclone structure of the gas-solid separation reactor 3. The non-alkaline tail gas is sent to the tail gas treatment device 4, while the powdered solid reactants are sent to the third channel 203 of the nozzle 21 through the fourth gas path and input into the discharge tube to continue adsorption and chemical reaction with the plasma torch. The alkaline solution in the tail gas treatment device 4 performs a secondary reaction on the non-alkaline tail gas to achieve harmless treatment. Part of the secondary tail gas is discharged into the atmosphere, and part of the secondary tail gas is sent to the third channel 203 of the nozzle 21 through the branch pipe and input into the discharge tube as auxiliary gas. The powdered solid reactants after the reaction are collected in the waste bin 309.

[0176] The mixed gas and auxiliary gas are mixed through the gas distribution system 1. The sulfur hexafluoride (SF6) gas source 102, air compressor 103, and steam generator 104 input the mixed gas into the atmospheric pressure microwave plasma generator 2 through the second channel 202 of nozzle 21. The SF6 gas source 102 outputs gas at a flow rate of 500 L / h, the air compressor 103 provides air at 18000 L / h, and the steam generator 104 stably produces 3000 L / h of gas at 100°C using heating. The auxiliary gas source 101 outputs gas at a flow rate of 3000 L / h and inputs auxiliary gas into the atmospheric pressure microwave plasma generator 2 through the first channel 201 of nozzle 21.

[0177] Open the first discharge valve 303 of the powder silo 301 and start the cyclone separator to input Φ35-100 μm calcium oxide (CaO) and alumina (Al2O3) powdered porous active solid material 302 into the plasma inlet 304 of the gas-solid separation reactor 3. The material has mesopores with a pore size of 20-30 nm and a porosity of 0.5-0.8 cm⁻¹. 3 / g, with a mass ratio of 1:1. Calcium oxide (CaO) and alumina (Al2O3) powders are fed into the discharge tube through the third channel 203 of the nozzle 21 via a branch pipe. After circulating with the CaO and Al2O3 powders in the gas-solid separation chamber, the first discharge valve 303 of the powder hopper 301 is closed. The atmospheric pressure microwave plasma generator 2 is started, outputting adjustable microwaves of 2.45 GHz and 25 kW. The mixed gas is input through the second channel 202 of the nozzle 21 and forms a plasma torch through ionization to degrade sulfur hexafluoride (SF6). The reactor can also be equipped with a built-in thermocouple to monitor the reactor temperature in real time (800-1400℃).

[0178] The calcium oxide (CaO) and aluminum oxide (Al2O3) powders in the discharge tube adsorb the degradation products of sulfur hexafluoride (SF6) and undergo a chemical reaction to generate calcium fluoroaluminate, a cement mineral raw material. Calcium sulfoaluminate For non-alkaline tail gas, the reaction formula is as shown in Formula 1-5:

[0179] Formula 1

[0180] Formula 2

[0181] Formula 3

[0182] Formula 4

[0183] Formula 5

[0184] The powdered solid reactants and non-alkaline tail gas after the reaction are fed into the gas-solid separation chamber through the plasma inlet 304 connected to the outer tube 206 of the discharge tube. The gas-solid separation chamber separates the non-alkaline tail gas from the powdered solid reactants. The non-alkaline tail gas is discharged through the outlet 305 to the tail gas treatment device 4, while the powdered solid reactants are fed into the discharge tube through the fourth gas path to the third channel 203 of the nozzle 21, where they continue to be adsorbed and chemically react with the plasma torch. The alkaline solution in the tail gas treatment device 4 performs a secondary reaction on the non-alkaline tail gas, achieving harmless treatment. Part of the secondary tail gas is discharged into the atmosphere, and the remaining part is fed into the discharge tube through the fourth gas path to the third channel 203 of the nozzle 21 as an auxiliary gas. Before the end of the operation, the second discharge valve 308 of the waste bin 309 is opened to discharge the calcium fluoroaluminate, the cement mineral raw material generated after the reaction. and calcium sulfoaluminate Collected in waste bin 309.

[0185] Microwave plasma is a high-enthalpy plasma. The sulfur-oxygen-fluorine (SOF) ion / molecular products in the plasma torch can be further decomposed at high temperatures into sulfur dioxide (SO2), sulfur trioxide (SO3), and hydrogen fluoride (HF). HF and SO2 can directly participate in the above reactions. At high temperatures, SO3 can partially decompose into SO2 and O2, a reversible endothermic reaction. The chemical equation is: 2SO3 ⇌ 2SO2 + O2. O2 can also participate in the reaction. However, unreacted or reverse-reacted SO3 can be rendered harmless using the alkaline solution in the tail gas treatment device 4.

[0186] Figure 5 This is a schematic diagram showing the component detection results in the final emission gas of an embodiment of the present invention, as shown below. Figure 5 As shown, Fourier transform infrared spectroscopy results indicate that no sulfur hexafluoride (SF6) component was detected in the SF6 degradation products. Testing proved that with a SF6 treatment flow rate of 1 L / h, the degradation efficiency reached 100%, and the generation of harmful byproducts (such as sulfur dioxide (SO2) and hydrogen fluoride (HF)) was ≤0.1%.

[0187] Compared to portable reactors in related technologies, the processing flow rate is low. At a discharge power of 1kW, the processing flow rate for 2% sulfur hexafluoride (SF6) waste gas is at most 40 L / h, and the degradation rate decreases significantly with increasing SF6 concentration, making it difficult to meet the degradation requirements of large quantities of SF6. The SF6 processing flow rate of this embodiment is 3-4 times that of related technologies, reaching a maximum of 160 L / h, while maintaining a high degradation rate of nearly 100% (99%). This demonstrates better processing flow rate and degradation efficiency, meaning it can meet the degradation requirements of larger quantities of SF6.

[0188] It should be noted that the term "comprising" and its variations used in the embodiments of this invention are open-ended, meaning "including but not limited to". The term "based on" means "at least partially based on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments". The modifications of "one" and "a plurality" mentioned in the embodiments of this invention are illustrative and not restrictive, and those skilled in the art should understand that unless explicitly indicated otherwise in the context, they should be understood as "one or more".

[0189] The steps described in the method embodiments provided by the present invention can be performed in different orders and / or in parallel. Furthermore, the method embodiments may include additional steps and / or omit the steps shown. The scope of protection of the present invention is not limited in this respect.

[0190] The term "embodiment" in this specification refers to a specific feature, structure, or characteristic described in connection with an embodiment that may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily imply the same embodiment, nor does it imply independence or alternativeity from other embodiments. The various embodiments in this specification are described in a related manner, with reference to each other for similar or identical parts. In particular, for apparatus, device, and system embodiments, since they are substantially similar to method embodiments, the description is relatively simple, and relevant details are referred to in the description of the method embodiments.

[0191] The above embodiments merely illustrate several implementation methods of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of protection. It should be noted that those skilled in the art can make various modifications and improvements without departing from the inventive concept of the present invention, and these all fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.

Claims

1. A gas-solid reaction-enhanced SF6 waste gas degradation device, characterized in that, include: Plasma generator, gas-solid separation reactor, tail gas treatment device, and gas distribution system; The gas distribution system is used to mix SF6 with auxiliary gas; The plasma generator is connected to the gas distribution system and is used to ionize the mixture of SF6 and auxiliary gas to obtain a plasma torch, and to eject the plasma torch into the gas-solid separation reactor in the ejection direction. The gas-solid separation reactor includes a plasma inlet and a gas-solid separation chamber. A powder silo is provided at the plasma inlet, and the powder silo stores a powdered porous active solid material. The powdered porous active solid material comes into contact with the plasma torch and is heated. The gas-solid separation chamber has an opening at the top, which is connected to the plasma inlet. The gas-solid separation chamber also has an outlet at the top and a discharge port at the bottom. The gas-solid separation chamber is used to react heated powdered porous active solid material with the plasma to generate powdered solid reactants and non-alkaline tail gas, and to separate the tail gas and solid reactants after the reaction. The exhaust gas treatment device is connected to the outlet of the gas-solid separation chamber and is used to perform a secondary reaction on the non-alkaline exhaust gas discharged from the outlet to achieve harmless treatment.

2. The SF6 waste gas degradation device based on gas-solid reaction enhancement according to claim 1, characterized in that, The gas-solid separation chamber includes a cylindrical section and a conical section connected sequentially from top to bottom; The opening is located at the top of the cylindrical portion, the opening is connected to the plasma inlet, and the plasma inlet is tangent to the cylindrical portion; The discharge port is located at the bottom of the conical part, and a waste bin is also provided below the discharge port. A second discharge valve is provided at the inlet of the waste bin.

3. The SF6 waste gas degradation device based on gas-solid reaction enhancement according to claim 2, characterized in that, The shape and size of the opening are the same as those of the plasma inlet, which is cylindrical with a diameter of 3-20 cm. The cylindrical portion has a diameter of 5-30 cm and a vertical length of 10-60 cm; the conical portion has a vertical length of 15-80 cm, a top diameter the same as the cylindrical portion, and a bottom diameter of 2-6 cm.

4. The SF6 waste gas degradation device based on gas-solid reaction enhancement according to claim 2, characterized in that, In the vertical direction, the top of the outlet pipe is not higher than the lower edge of the plasma inlet.

5. The SF6 waste gas degradation device based on gas-solid reaction enhancement according to claim 4, characterized in that, In the vertical direction, the distance between the top of the outlet pipe and the lower edge of the plasma inlet is 5-20cm. The diameter of the air outlet 305 is 2-15 cm; In the vertical direction, the distance between the top of the air outlet pipe and the top of the cylindrical part is 8-25 cm.

6. The SF6 waste gas degradation device based on gas-solid reaction enhancement according to claim 1, characterized in that, The output gas of the exhaust gas treatment device is also connected to the nozzle through a fourth gas path; The discharge port at the bottom of the gas-solid separation chamber is also connected to the fourth gas path.

7. The SF6 waste gas degradation device based on gas-solid reaction enhancement according to claim 1, characterized in that, The powder hopper is located above the plasma inlet, and a first discharge valve is provided between the powder hopper and the plasma inlet for discharging the powdered porous active solid material to the plasma inlet at a fixed rate and mixing and reacting with the plasma torch.

8. The SF6 waste gas degradation device based on gas-solid reaction enhancement according to claim 1, characterized in that, The exhaust gas treatment device is equipped with a mixed solution of sodium hydroxide (NaOH) and calcium hydroxide (Ca(OH)2) with a capacity of 5-15L. The concentration of sodium hydroxide (NaOH) is 0.5-0.8 mol / L, and the concentration of calcium hydroxide (Ca(OH)2) is 0.2-0.5 mol / L. The mixed solution also contains solid particles to ensure that the gas-liquid contact time is ≥10 s.

9. The SF6 waste gas degradation device based on gas-solid reaction enhancement according to claim 1, characterized in that, The porous active solid material is a mesoporous material, which has a hierarchical pore structure including micron-sized and nano-sized pores, with a porosity of 0.5-0.8 cm⁻¹. 3 / g, the layered pore structure contains mesopores, the diameter of which is 10nm-40nm.

10. The SF6 waste gas degradation device based on gas-solid reaction enhancement according to claim 1, characterized in that, The plasma torch contains HF, SO2, and SOF ion / molecule products; The main component of the porous active solid material is a metal oxide; The metal oxide includes at least one of the following: iron oxide, Al2O3, MgO, and CaO.

11. The SF6 waste gas degradation device based on gas-solid reaction enhancement according to claim 1, characterized in that, The plasma generator includes a nozzle, a waveguide device, and a discharge tube; The waveguide device is a rectangular waveguide; the rectangular waveguide is provided with mounting holes, and the mounting holes match the cross-sectional shape of the discharge tube; The nozzle is a multi-gas-channel nozzle; the multiple gas channels of the nozzle include a first channel for transmitting the auxiliary gas, a second channel for transmitting the SF6, and a third channel for recovering a portion of the powdered porous active solid material. The discharge tube is a double-layered cylindrical tube, which includes an outer tube and an inner tube. The outer tube is fixed on the waveguide device, and the nozzle is disposed at one end of the inner tube to accommodate the plasma torch in the inner tube.

12. The SF6 waste gas degradation device based on gas-solid reaction enhancement according to claim 11, characterized in that, The power of the rectangular waveguide is 1-50 kW; The plasma torch is 15-75 cm long, the inner tube can withstand high temperatures ≥1500℃, and the inner tube has a diameter of 2-7 cm and a length of 4-25 cm. The outer tube has a diameter of 3-20 cm and a length of 20-120 cm. The diameter of the outer tube is larger than that of the inner tube. In the radial direction, the distance between the outer tube and the inner tube is 1-10 cm.

13. The SF6 waste gas degradation device based on gas-solid reaction enhancement according to claim 2, characterized in that, The gas distribution system includes an SF6 gas source, an auxiliary gas source, a steam generator, and an air compressor. The first gas path of the auxiliary gas source is connected to the first channel of the nozzle; The second air passage of the SF6 gas source is connected to the first pressurizing air passage of the air compressor, and the second air passage of the SF6 gas source is also connected to the second channel of the nozzle; The third air passage of the steam generator is connected to the second pressurized air passage of the air compressor; Both the first pressurized air path and the second pressurized air path are connected to the nozzle.

14. A method for degrading SF6 waste gas based on gas-solid reaction enhancement, characterized in that, include: SF6 is mixed with auxiliary gas through a gas distribution system and then fed into the plasma generator. The SF6 is mixed with the auxiliary gas by a plasma generator, ejected in a predetermined ejection direction, and ionized to form a plasma torch. By adding powdered porous active solid material to the plasma torch, the particles of the plasma torch are adsorbed and a chemical reaction occurs, generating powdered solid reactants and non-alkaline exhaust gas. The solid reactants and non-alkaline exhaust gas are separated in a gas-solid separation chamber in the direction of plasma torch ejection. The gas-solid separation reactor includes a plasma inlet and a gas-solid separation chamber. A powder hopper is provided at the plasma inlet, and the powder hopper stores powdered porous active solid material. The top of the gas-solid separation chamber is provided with an opening that communicates with the plasma inlet. The top of the gas-solid separation chamber is also provided with a gas outlet, and the bottom of the gas-solid separation chamber is provided with a material outlet. The non-alkaline exhaust gas is transferred to an exhaust gas treatment device, where it undergoes a secondary reaction in an alkaline solution to achieve harmless treatment.

15. The SF6 waste gas degradation method based on gas-solid reaction enhancement according to claim 14, characterized in that, Before the SF6 is mixed with the auxiliary gas via a gas mixing system and introduced into the plasma generator, the method further includes: The auxiliary gas is input, and the powder hopper is opened. A gas circulation is formed through the gas-solid separation chamber and the fourth gas path connected to the outlet of the gas-solid separation chamber. The powder hopper is then closed. After separating the solid reactants and the non-alkaline tail gas in the gas-solid separation chamber in the plasma torch ejection direction, the method further includes: The separated solid reactants are recycled to the waste bin, and the powder bin is opened to replenish the powder and continue the reaction with the plasma torch. The non-alkaline exhaust gas is transferred to an exhaust gas treatment device, where it undergoes a secondary reaction in an alkaline solution to achieve harmless treatment. The method further includes: The output gas from the exhaust gas treatment device is transmitted to a nozzle as an auxiliary gas for plasma reaction.

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