A plasma device for treating industrial wastewater

Abstract

The application discloses a kind of plasma device for treating industrial wastewater, and its plasma reactor includes multiple groups of parallelly arranged annular sub-reactors and electrode fixer;Each group of sub-reactors includes multiple annular high-voltage electrodes, foam copper electrode plate;Multiple annular high-voltage electrodes are arranged with spacing in upper and lower alignment, wherein the middle part is inserted into foam copper electrode plate;Metal plate is arranged between adjacent two sub-reactors;Foam copper electrode plate and metal plate are parallelly arranged and form plasma reaction electric field between annular high-voltage electrode;Multiple groups of sub-reactors are fixed by electrode fixer;Liquid flowing out from water inlet device enters liquid product collector through plasma reaction electric field.The application not only reduces the initial voltage of discharge, increases the discharge area, generates more active particles for degrading pollutants in wastewater, but also enhances the energy utilization efficiency of the overall device, achieves the effect of high efficiency and low energy consumption.

Description

Technical Field

[0001] This invention relates to the field of plasma wastewater treatment technology, and more specifically to a plasma device for treating industrial wastewater. Background Technology

[0002] In recent years, with the rapid development of my country's industrialization, the discharge of toxic and harmful industrial wastewater has increased significantly. Statistics show that industrial wastewater accounts for nearly one-third of total sewage discharge, and its contribution to water pollution exceeds 40%, seriously endangering the ecological environment. Commonly used wastewater treatment methods mainly fall into two categories: physical and chemical. Physical methods are simple to operate, widely applicable, and can effectively recover or filter pollutants, but they cannot completely treat pollutants, and their high cost and potential for secondary pollution cannot be ignored. Chemical treatment methods have good treatment effects on specific pollutants, but the addition of chemical reagents not only increases treatment costs but may also bring additional environmental risks.

[0003] Based on the non-thermal equilibrium characteristics of low-temperature plasma technology, its application in water treatment has been increasingly studied in recent years. Extensive experiments and research have shown that during low-temperature plasma discharge, a large number of high-energy electrons, ions, atoms, and free radicals exist. These active particles constantly collide with each other, triggering various chemical reactions, thereby producing diverse active substances with strong oxidizing or reducing properties and ionizing radiation. Especially in plasmas discharging at the gas-liquid interface, which contain oxidizing molecules, hydrated electrons, and ultraviolet light, these active components interact with organic compounds in the liquid phase, leading to the decomposition of organic pollutants. Simultaneously, the plasma reaction occurs at ambient temperature and pressure, avoiding the high energy consumption of high-temperature and high-pressure equipment. Furthermore, the ultraviolet radiation and reactive oxygen species (ROS) generated by plasma can efficiently inactivate bacteria and viruses in wastewater (inactivation rate >99.9%), and some technologies can recover heavy metals (such as Cu and Ag) or generate reusable gases (H2 and CO). Therefore, the application of low-temperature plasma in wastewater treatment has broad application prospects.

[0004] A pulsed discharge plasma reactor and an organic wastewater treatment device disclosed in the prior art with the publication number CN212492881U uses a microsecond pulsed high-voltage power supply to generate plasma to achieve efficient degradation of wastewater. However, the output energy that the pulsed excitation source can provide is limited, it cannot drive a large reaction device, and its cost is relatively high. Secondly, there will be a large amount of impurity residues after treating sewage, but the overall structure of the device is relatively complex, so the overall cost is high and the later maintenance difficulty is also large. A device and method for generating plasma in water using a DC source disclosed in the publication number CN112616234A. Due to the short time of the arc plasma generated in this device and the small formed discharge area, it is difficult to obtain good wastewater treatment effect under large flow rate.

[0005] Therefore, while ensuring the efficiency and stability of industrial wastewater treatment, how to achieve cost optimization, green sustainable development, and effective control of product toxicity in the treatment process has become a key technical problem that亟待解决 (needs to be solved urgently) at present. Summary of the Invention

[0006] 1. Technical problems to be solved: In view of the above technical problems, the present invention provides a plasma device for treating industrial wastewater, which can achieve an industrial wastewater treatment device with efficient treatment, intelligent regulation, simple operation, and easy maintenance.

[0007] 2. Technical solutions: A plasma device for treating industrial wastewater, characterized in that it includes a water inlet device, a plasma reactor, and a liquid product collector; the water inlet device is provided with a water inlet for introducing industrial wastewater, and the wastewater entering the water inlet device flows into the plasma reactor located below it after passing through a particle filter; the plasma reactor includes multiple groups of annular sub-reactors arranged in parallel and an electrode holder; each group of annular sub-reactors includes multiple annular high-voltage electrodes and a grounded copper foam electrode plate; the multiple annular high-voltage electrodes are arranged vertically and at intervals, and the middle part of them is inserted into the copper foam electrode plate; a metal plate is provided between adjacent two sub-reactors; the copper foam electrode plate and the metal plate are arranged in parallel and form a plasma reaction electric field with the annular high-voltage electrodes; multiple groups of sub-reactors are fixed through the electrode holder; the liquid flowing out of the water inlet device enters the liquid product collector through the plasma reaction electric field.

[0008] Further, the annular high-voltage electrode is in an elongated "hui" shape, and all four sides are cylindrical dielectric layers, and high-voltage electrodes are symmetrically provided on two long sides; the high-voltage electrode is a spiral metal wire or a cylindrical metal mesh, which is coaxially sleeved inside the dielectric layer cylinder, and the extending direction of the high-voltage electrode is the same as the extending direction of the long side; the wiring port of the high-voltage electrode is located at one of the short sides.

[0009] Furthermore, the electrode holder includes a square outer shell, a metal plate, a side sealing cover, and a ground electrode fixing plate; the plasma reactor is located in the inner cavity of the outer shell, and the metal plate is located between two adjacent sub-reactors; the ground electrode fixing plate is detachably wrapped around the foamed copper electrode plate; the two vertical sides of the ground electrode fixing plate are provided with grooves for placing the short side of the annular high-voltage electrode; the two long sides of the annular high-voltage electrode are each formed by two detachable dielectric layer cylinders connected together; the side sealing cover is located on one side of the outer shell, and its inner wall is provided with grooves for installing the metal plate and grooves for installing the ground electrode fixing plate; when installing or replacing the annular high-voltage electrode, the two dielectric layer cylinders of the long side are respectively connected or separated from the left and right ends of the ground electrode fixing plate.

[0010] Furthermore, the square outer shell of the electrode holder is a hollow cube with an open top, with an outer length of 200-220 mm, an outer width of 200-220 mm, and a wall thickness of 6-7 mm; the dielectric layer of the annular high-voltage electrode is a hollow polytetrafluoroethylene rod with an outer diameter of 20-22 mm, a thickness of 2-3 mm, and a length of 160-180 mm, and its four sides are connected by connectors; the high-voltage electrode has an outer diameter of 16-18 mm, an inner diameter of 12-14 mm, and a length of 180 mm; the dimensions of the foamed copper electrode plate are: length 170-190 mm, width 170-190 mm, and thickness 2-3 mm. During installation, after fitting it onto the grounding electrode fixing plate, the annular high-voltage electrode is installed and fixed into the corresponding groove, allowing the entire structure to be inserted into the cavity of the electrode holder shell from the top of the outer shell; the length and width of the foamed copper electrode plate after fitting it onto the grounding electrode fixing plate are both 200-220 mm, and the thickness is 6-7 mm.

[0011] Furthermore, the distance between the surface of the metal plate and the annular high-voltage electrode is 1~3mm; the distance between the foamed copper electrode plate and the annular high-voltage electrode is 1~3mm.

[0012] Furthermore, each set of annular sub-reactors includes three annular high-voltage electrodes; each device includes two sets of annular sub-reactors.

[0013] Furthermore, the water inlet device is square and is located on the upper part of the electrode holder housing. Its water inlet is also provided with a circulation pipe inlet. The circulation pipe inlet is connected to the outlet of the liquid product collector through a circulation pump.

[0014] Furthermore, the liquid product collector is square and located at the bottom of the electrode holder housing. It is equipped with a water quality detector and an activated carbon filter. The water quality detector tests the treated industrial wastewater. If it meets the discharge standards, the main drain outlet is opened. If the test fails to meet the standards, the liquid will be re-entered into the inlet device for treatment through the circulation pipe under the action of the circulation pump.

[0015] 3. Beneficial effects: (1) The present invention provides a plasma device for treating industrial wastewater. Through a unique structure of a ring-shaped high-voltage electrode, a grounded foamed copper electrode plate and a metal plate, a three-electrode structure is formed. The ring-shaped electrode is used as a high-voltage electrode to generate an asymmetric electric field, optimize the electric field distribution, reduce the energy required for discharge, and form a multi-level discharge channel, which increases the discharge area and reduces the overall energy consumption. At the same time, a three-electrode dielectric barrier discharge plasma device with multiple microchannel discharge is formed. The physical microchannels (structural channels) include porous dielectric permeation channels, in which the interconnected pores inside the foamed copper electrode plate constitute a material transport nanochannel; the discharge microchannels (plasma channels) include filamentary discharge microchannels, surface discharge microchannels, and body discharge microchannels; the electric field modulation microchannels (virtual channels) include (1) an asymmetric electric field line channel, i.e., a radial non-uniform electric field is formed between the ring electrode and the flat plate ground electrode; (2) a three-electrode coupling channel, i.e., the third electrode (suspended or biased electrode) induces a secondary discharge microchannel between the ring-ground main channel. Multiple microchannel discharges not only reduce the initial discharge voltage, increase the discharge area, and generate more active particles to degrade pollutants in wastewater, but also enhance the overall energy utilization efficiency of the device, achieving a high-efficiency and low-energy-consumption effect.

[0016] (2) The present invention provides a plasma device for treating industrial wastewater. It uses foamed copper as the electrode material and its special structure with the electrode. Under the same input power and electrode length, it can form an effective discharge area twice the length of the electrode. Combined with the special structure of the foamed copper electrode plate with overall porous structure, it greatly improves the residence time of pollutants in the plasma area of ​​the wastewater, which is beneficial to obtaining better treatment effect. Through circulation, the treated liquid can reach different indicators, which enhances the wastewater treatment effect and improves its universality, meeting the treatment needs of different fields.

[0017] (3) The plasma device for treating industrial wastewater provided by the present invention uses a foamed copper electrode plate with a porous structure. Under the excitation of an alternating electric field, in addition to generating spatial discharge with the corresponding annular high-voltage electrode, discharge can also be generated inside the pores of its structure, forming more discharge channels, which is conducive to the generation of active substances. In addition, the porous structure can effectively prolong the residence time of pollutants in the discharge plasma area, enhance the contact time between pollutants and plasma, and improve the wastewater treatment effect.

[0018] (4) The plasma device for treating industrial wastewater provided by the present invention has a modular electrode structure. The number of electrodes can be flexibly adjusted to meet the specific needs of different scenarios. It is highly versatile and easy to replace, maintain and inspect later. Attached Figure Description

[0019] Figure 1 This is an overall schematic diagram of the plasma device of the present invention; Figure 2 This is a schematic diagram of the plasma reactor in this invention; Figure 3 This is a schematic diagram of the annular high-voltage electrode in this invention; Figure 4 This is a cross-sectional view of the plasma device of the present invention; Figure 5 This is a schematic diagram of the liquid product collector in this invention; Figure 6 This is a schematic diagram of the side sealing cap in this invention; Figure 7 This is a schematic diagram of the ground electrode fixing plate in this invention.

[0020] Figure 8 This is a flowchart illustrating the industrial wastewater treatment process using the present invention in a specific embodiment; Figure 9 To verify the effect of adjusting the input voltage on the reaction characteristics in the example; Figure 10 To verify the effect of different frequencies on hydrogen peroxide production in the example; Figure 11 To verify the effect of cycle number and number of electrodes on hydrogen peroxide production in the example, a graph is shown. Figure 12 To verify the hydrogen peroxide content of foamed copper and copper plate under the same working conditions in the example.

[0021] Explanation of reference numerals in the attached diagram: 1. Inlet; 2. Particle filter; 3. Electrode holder; 4. Metal plate; 5. Water quality detector; 6. Liquid product collector; 601. Inlet of circulation pipe; 7. Circulation pipe; 8. Circulation pump; 9. Side sealing cover; 10. Annular high-voltage electrode; 101. Medium layer cylinder; 102. Spiral metal wire or cylindrical metal mesh; 103. Connection port of high-voltage electrode; 104. Connector; 11. Foamed copper electrode plate; 12. Activated carbon filter; 13. Outlet; 14. Ground electrode fixing plate. Detailed Implementation

[0022] The present invention will now be described in detail with reference to the accompanying drawings.

[0023] As attached Figure 1 To be continued Figure 7As shown in the figure, a plasma device for treating industrial wastewater is characterized in that it includes a water inlet device, a plasma reactor, and a liquid product collector; the water inlet device is provided with a water inlet 1 for introducing industrial wastewater, and the wastewater entering the water inlet device flows into the plasma reactor located below it after passing through a particle filter 2; the plasma reactor includes multiple groups of annular sub-reactors arranged side by side and an electrode holder 3; each group of annular sub-reactors includes multiple annular high-voltage electrodes 10 and a grounded copper foam electrode plate 11; the multiple annular high-voltage electrodes are arranged at intervals with the upper and lower parts aligned, and the middle part thereof is inserted into the copper foam electrode plate; a metal plate 4 is provided between adjacent two sub-reactors; the copper foam electrode plate and the metal plate are arranged in parallel and form a plasma reaction electric field with the annular high-voltage electrodes; the multiple groups of sub-reactors are fixed by the electrode holder; the liquid flowing out of the water inlet device enters the liquid product collector 6 through the plasma reaction electric field.

[0024] Further, the annular high-voltage electrode is in the shape of a long "hui" character, and all four sides are cylindrical dielectric layers, and high-voltage electrodes are symmetrically provided on two long sides; the high-voltage electrode is a spiral metal wire or a cylindrical metal mesh 102, which is coaxially sleeved inside the dielectric layer cylinder 101, and the extending direction of the high-voltage electrode is the same as the extending direction of the long side; the connection port 103 of the high-voltage electrode is located at one of the short sides. In the figure, 104 is a connector connecting the long side and the short side.

[0025] Further, the electrode holder includes a square outer shell, a metal plate, a side sealing cover 9, and a ground electrode fixing plate 14; the plasma reactor is arranged in the inner cavity of the outer shell, and the metal plate is located between adjacent two sub-reactors; the ground electrode fixing plate is detachably wrapped around the copper foam electrode plate; grooves for placing the short sides of the annular high-voltage electrodes are provided on two vertical sides of the ground electrode fixing plate; both long sides of the annular high-voltage electrode are connected by two detachable dielectric layer cylinders; the side sealing cover is located on one side of the outer shell, and grooves for installing the metal plate and grooves for installing the ground electrode fixing plate are provided on its inner wall; when installing or replacing the annular high-voltage electrode, the two dielectric layer cylinders of the long side are respectively docked or separated from the left and right ends of the ground electrode fixing plate.

[0026] Furthermore, the square outer shell of the electrode holder is a hollow cube with an open top, with an outer length of 200-220 mm, an outer width of 200-220 mm, and a wall thickness of 6-7 mm; the dielectric layer of the annular high-voltage electrode is a hollow polytetrafluoroethylene rod with an outer diameter of 20-22 mm, a thickness of 2-3 mm, and a length of 160-180 mm, and its four sides are connected by connectors; the high-voltage electrode has an outer diameter of 16-18 mm, an inner diameter of 12-14 mm, and a length of 180 mm; the dimensions of the foamed copper electrode plate are: length 170-190 mm, width 170-190 mm, and thickness 2-3 mm. During installation, after fitting it onto the grounding electrode fixing plate, the annular high-voltage electrode is installed and fixed into the corresponding groove, allowing the entire structure to be inserted into the cavity of the electrode holder shell from the top of the outer shell; the length and width of the foamed copper electrode plate after fitting it onto the grounding electrode fixing plate are both 200-220 mm, and the thickness is 6-7 mm.

[0027] Furthermore, the distance between the surface of the metal plate and the annular high-voltage electrode is 1~3mm; the distance between the foamed copper electrode plate and the annular high-voltage electrode is 1~3mm.

[0028] Furthermore, each set of annular sub-reactors includes three annular high-voltage electrodes; each device includes two sets of annular sub-reactors.

[0029] Furthermore, the water inlet device is square and is located on the upper part of the electrode holder housing. Its water inlet is also provided with a circulation pipe 7 water inlet 601. The circulation pipe water inlet is connected to the outlet 13 of the liquid product collector through a circulation pump 8.

[0030] Furthermore, the liquid product collector is square and located at the bottom of the electrode holder housing. It is equipped with a water quality detector 5 and an activated carbon filter 12. The water quality detector tests the treated industrial wastewater. If it meets the discharge standards, the main drain outlet is opened. If the test fails to meet the standards, the liquid will re-enter the inlet device for treatment through the circulation pipe under the action of the circulation pump. Specific Implementation

[0031] As attached Figure 8 The diagram shows a flowchart of the process for treating industrial wastewater using this device, which can be divided into five steps: feeding untreated industrial wastewater into the device, connecting the power supply and adjusting the parameters, treating the wastewater with plasma, detecting the products, and discharging industrial wastewater that meets the standards.

[0032] This device utilizes foamed copper as the first ground electrode, a ring-shaped high-voltage electrode, and a metal plate as the second ground electrode, forming a three-electrode dielectric barrier discharge device. A discharge plasma region is formed between the foamed copper electrode plate and the ring-shaped high-voltage electrode. Simultaneously, the surface of the foamed copper electrode plate has a rich porous structure, which can form multiple discharge channels under an alternating electric field, increasing the contact time between pollutants and plasma. Furthermore, the ring-shaped high-voltage electrode design generates a higher electric field in the arc portion, which facilitates the formation of discharge channels, thus reducing the breakdown voltage required for discharge. At the same time, under the same input voltage, discharge plasma is also formed between the ring-shaped high-voltage electrode and the metal plate, not only increasing the effective discharge plasma region and the contact area between industrial wastewater and the reactor, thus improving the device's pollutant treatment capacity, but also reducing energy consumption. Combined with a detection and circulation system, it enables multiple treatments of industrial wastewater that does not meet emission standards, ensuring better treatment results. Moreover, all electrodes used in this device can be easily disassembled and reassembled, greatly reducing the difficulty and cost of equipment maintenance.

[0033] Verification Example 1: This verification example is used to verify the control of the input voltage of this device, which controls the core parameters of discharge intensity, active species generation efficiency, and H2O2 yield. The results are attached. Figure 9 As shown in the figure, experiments demonstrate that optimizing voltage parameters can significantly increase the concentration of active substances such as H2O2 and hydroxyl radicals (·OH), thereby enhancing the oxidative degradation capacity of organic pollutants and ultimately achieving a more efficient wastewater treatment effect. Input voltage is a crucial reaction condition affecting wastewater treatment. By adjusting the input voltage of the reaction, the content of hydrogen peroxide, an active substance generated by the discharge of deionized water, was studied. The experimental results are as follows: Figure 7 As shown in the figure, experiments indicate that the amount of hydrogen peroxide generated gradually increases with increasing input voltage, reaching a maximum of 27.39%. Energy efficiency initially decreases gradually, reaching a maximum of 12.24 g / kWh at an input voltage of 13 kV. The hydrogen peroxide content reaches its highest point of 27.39% at an input voltage of 15 kV.

[0034] Example 2: This example verifies the effect of different power supply frequencies on hydrogen peroxide production. In plasma wastewater treatment systems, adjusting the power supply frequency is one of the key parameters controlling the reaction process. By adjusting the discharge frequency, the micro-discharge density and electron energy distribution can be effectively altered, thereby affecting the generation rate of reactive species such as hydroxyl radicals (·OH), ultimately achieving precise control over the degradation efficiency of organic matter and the yield of hydrogen peroxide (H2O2). This study investigates the effect of adjusting the input frequency on hydrogen peroxide production. Experimental results are as follows: Figure 10As shown, the production of hydrogen peroxide first increases and then decreases with increasing discharge frequency. This may be because in the low-frequency region, the number of discharges per unit time increases significantly with increasing frequency, resulting in more uniform micro-discharges. However, in the high-frequency region, the thermal effect generated by the discharge leads to the decomposition of hydrogen peroxide, resulting in a decrease in hydrogen peroxide production.

[0035] Verification Example 3: This verification example is used to verify the effects of the number of cycles and the number of electrodes on the hydrogen peroxide production. In the plasma wastewater treatment system, the amount of hydrogen peroxide (H2O2) generated exhibits a non-linear cumulative characteristic with reaction time. By adjusting the number of cycles, the residence time of wastewater in the plasma activation zone can be controlled, thereby optimizing the free radical contact efficiency and extending the residence time to promote the mass transfer reaction between active substances such as ·OH and wastewater. This study increased the number of cycles and the number of high-voltage electrodes to increase the reaction time of deionized water in the reaction zone, in order to explore the effect of reaction time on the wastewater treatment performance. Experimental results are as follows: Figure 11 As shown, with the increase of the number of cycles and the corresponding increase of the reaction time, the production of hydrogen peroxide shows an upward trend. This indicates that with the increase of the number of cycles and the increase of the reaction time, the production of hydrogen peroxide will also increase, and the wastewater treatment effect will be better.

[0036] Verification Example 4: This verification case is used to verify the hydrogen peroxide content generated by this device using foamed copper and copper plates under the same operating conditions. The results are attached. Figure 12 As shown, at the same power frequency, using copper foam as the electrode material can generate more active hydrogen peroxide. This is because the network structure of copper foam can break large bubbles into microbubbles, increasing the gas-liquid contact efficiency, which is very beneficial for hydrogen peroxide generation. At the same time, the biggest advantage of copper foam is the increased specific surface area brought about by its three-dimensional porous structure. Ordinary copper plate electrodes have limited contact area, while the internal pores of copper foam can significantly increase the gas-liquid-solid three-phase reaction interface.

[0037] Although the present invention has been disclosed above with reference to preferred embodiments, these are not intended to limit the invention. Any person skilled in the art can make various changes or modifications without departing from the spirit and scope of the invention. Therefore, the scope of protection of the present invention should be defined by the scope of the claims of this application.

Claims

1. A plasma device for treating industrial wastewater, characterized in that: It includes a water inlet device, a plasma reactor, and a liquid product collector; the water inlet device is provided with a water inlet for introducing industrial wastewater, and the wastewater entering the water inlet device flows into the plasma reactor located below it after passing through a particle filter; the plasma reactor includes multiple groups of annular sub-reactors arranged side by side and an electrode holder; each group of annular sub-reactors includes multiple annular high-voltage electrodes and a grounded copper foam electrode plate; the multiple annular high-voltage electrodes are arranged vertically and at intervals, and the middle part thereof is inserted into the copper foam electrode plate; a metal plate is provided between adjacent sub-reactors; the copper foam electrode plate and the metal plate are arranged in parallel and form a plasma reaction electric field with the annular high-voltage electrodes; multiple groups of sub-reactors are fixed by the electrode holder; the liquid flowing out of the water inlet device enters the liquid product collector through the plasma reaction electric field; the annular high-voltage electrode is in the shape of a long "return" character, and all four sides are cylindrical dielectric layers, and high-voltage electrodes are symmetrically provided on two long sides; the high-voltage electrode is a spiral metal wire or a cylindrical metal mesh, which is coaxially sleeved inside the dielectric layer cylinder, and the extending direction of the high-voltage electrode is the same as the extending direction of the long side; the wiring port of the high-voltage electrode is located at one of the short sides.

2. The plasma device for treating industrial wastewater according to claim 1, characterized in that: The electrode holder includes a square outer shell, a metal plate, a side sealing cover, and a ground electrode fixing plate; the plasma reactor is arranged in the inner cavity of the outer shell, and the metal plate is located between adjacent two sub-reactors; the ground electrode fixing plate is detachably wrapped around the copper foam electrode plate; grooves for placing the short sides of the annular high-voltage electrodes are provided on two vertical sides of the ground electrode fixing plate; both long sides of the annular high-voltage electrode are connected by two detachable dielectric layer cylinders; the side sealing cover is located on one side of the outer shell, and grooves for installing the metal plate and grooves for installing the ground electrode fixing plate are provided on its inner wall; when installing or replacing the annular high-voltage electrode, the two dielectric layer cylinders on the long side are respectively docked or separated from the left and right ends of the ground electrode fixing plate.

3. A plasma device for treating industrial wastewater according to claim 2, characterized in that: The square outer shell of the electrode holder is a hollow cube with an open upper end, its outer length is 200 - 220 mm, outer width is 200 - 220 mm, and wall thickness is 6 - 7 mm; the dielectric layer cylinder of the annular high-voltage electrode is a hollow polytetrafluoroethylene rod with an outer diameter of 20 - 22 mm, a thickness of 2 - 3 mm, and a length of 160 - 180 mm, and its four sides are connected by connectors; the outer diameter of the high-voltage electrode therein is 16 - 18 mm, inner diameter is 12 - 14 mm, and length is 180 mm; the size of the copper foam electrode plate is: length 170 - 190 mm, width 170 - 190 mm, and thickness 2 - 3 mm. When installing, after sleeving it on the ground electrode fixing plate, the annular high-voltage electrode is installed and fixed into the corresponding groove, and the overall structure can be inserted into the cavity of the electrode holder outer shell from the upper end of the outer shell; the length and width of the copper foam electrode plate after sleeving the ground electrode fixing plate are both 200 - 220 mm, and the thickness is 6 - 7 mm.

4. A plasma device for treating industrial wastewater according to claim 3, characterized in that: The distance between the surface of the metal plate and the annular high-voltage electrode is 1 - 3 mm; the distance between the copper foam electrode plate and the annular high-voltage electrode is 1 - 3 mm.

5. A plasma device for treating industrial wastewater according to claim 1, characterized in that: Each set of ring sub-reactors includes three ring-shaped high-voltage electrodes; each device includes two sets of ring sub-reactors.

6. A plasma device for treating industrial wastewater according to claim 2, characterized in that: The water inlet device is square and is located on the upper part of the electrode holder housing. Its water inlet is also equipped with a circulation pipe inlet. The circulation pipe inlet is connected to the outlet of the liquid product collector through a circulation pump.

7. A plasma device for treating industrial wastewater according to claim 2, characterized in that: The liquid product collector is square and located at the bottom of the electrode holder housing. It is equipped with a water quality detector and an activated carbon filter. The water quality detector tests the treated industrial wastewater. If it meets the discharge standards, the main drain outlet is opened. If the test fails to meet the standards, the liquid will be re-entered into the inlet device for treatment through the circulation pipe under the action of the circulation pump.

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