Large-space high-density discharge plasma device and application thereof

Abstract

The invention belongs to the field of material processing, energy and environmental protection, and relates to a large-space high-density discharge plasma device and application thereof.The discharge plasma device is formed by combining a movable micron-sized filiform brush electrode and a matched discharge initiation electrode, the advantages of low-temperature plasma and arc discharge are combined, and high-density discharge is achieved. By controlling the distance between the electrode pairs, large-space high-strength uniform discharge under low initiation voltage is realized. Compared with the prior art, the plasma device provided by the invention has the advantages of wide adjustable range of discharge energy density, large space and multiple purposes.

Description

Technical Field

[0001] The invention belongs to the fields of material processing, energy and environmental protection, and in particular relates to a large-space high-density discharge plasma device and its application. Background Art

[0002] Plasma activates gas molecules by ionization, excitation and dissociation, generating a large number of active species, thereby generating high-density electrons. According to the different gas pressures, plasmas are divided into low-pressure (<10Torr) plasmas, medium-pressure (10-100Torr) plasmas and high-pressure (>100Torr) plasmas; according to the different temperatures, plasmas are divided into thermal plasmas and non-thermal plasmas.

[0003] Conventional low-temperature discharge plasma refers to the temperature (>10 4K) is much higher than the ion temperature (=300 ~ 500K) of the plasma, so it can maintain discharge balance under low energy consumption. Conventional low-temperature discharge plasma is often used in the fields of material surface treatment and modification and carbon reduction. For example, in response to the problem of insufficient bonding performance of polytetrafluoroethylene (PTFE) materials that have been widely used in medical, aerospace, electronics and other industries, patent application CN116836443A discloses a method of modifying the PTFE surface by using argon or a mixed gas plasma containing argon, modifying the PTFE structure and thus solving the problem of insufficient PTFE bonding strength. In addition, patent application CN117116747A discloses a method of using argon and ammonia mixed plasma to treat surface traps and dangling bonds in silicon carbide, a material in the semiconductor field, to improve the flatness of the silicon carbide surface. Patent application CN117142433A discloses a method for utilizing the synergistic effect between plasma and catalyst, adding Ni-based catalyst to DBD plasma reactor to carry out synergistic resource treatment of CO2 and VOCs (alkanes, olefins, alcohols, benzene series, etc.) at normal temperature and pressure, thereby improving the selectivity and energy utilization efficiency of different products of catalytic reforming of carbon dioxide. Patent application CN116676689A discloses a method for preparing spiral carbon fiber by arc discharge under atmospheric pressure, which can switch growth conditions within a few seconds, control spiral carbon fiber to be in different growth environments at different time periods, so that spiral carbon fiber has the ability to re-nodulate and grow on the surface, and simplifies the growth difficulty of spiral carbon fiber. This method utilizes the advantages of fast arc discharge switching temperature and high temperature peak to prepare carbon fiber reinforced composite materials with isotropic mechanical properties that chemical vapor deposition method does not have. In summary, conventional low-temperature discharge plasma has been widely used in the fields of material surface treatment and modification and carbon reduction. However, due to the low energy density of conventional low-temperature discharge plasma and the limited chemical reaction capacity, its large-scale use is limited.

[0004] Arc is a common thermal plasma that can generate high current density (about 10 3 A / cm 2 ) has a strong brightness arc column, and the temperature on its channel and electrode is about 7000-8000℃. Due to the high temperature, arc discharge can be used to process high-temperature materials. Patent CN118175710A provides a plasma generation device and a method for preparing industrial raw materials with plasma, which improves an efficient method for preparing low-temperature plasma and generating arcs. However, this patent is difficult to meet the needs of large-space high-density discharge plasma.

[0005] High-temperature plasma represented by arc discharge has problems such as small discharge channel, excessive energy concentration and severe electrode ablation. Summary of the invention

[0006] The purpose of the present invention is to provide a large-space high-density discharge plasma device and its application in order to overcome the defects of the above-mentioned prior art. The discharge plasma device is composed of a movable micron-level filamentary brush electrode and a matching discharge initiation electrode. It combines the advantages of low-temperature plasma and arc discharge, and realizes high-intensity uniform discharge in a large space under low initiation voltage by controlling the spacing between electrode pairs.

[0007] The object of the present invention can be achieved by the following technical scheme: A large space high density discharge plasma device comprises a shell, and an upper electrode, a lower electrode and an initiation electrode located inside the shell;

[0008] The upper electrode and the lower electrode are electrodes with micron fine wire brushes, including a conductive substrate and a conductive micron wire bundle embedded in the conductive substrate;

[0009] The triggering electrode is a movable electrode with multiple needle tips, including a conductive bracket and a needle-shaped electrode embedded thereon. One end of the needle-shaped electrode passes through the upper electrode and is fixed on the conductive bracket, and the other end is suspended above the lower electrode. The conductive bracket moves up and down, driving the needle-shaped electrode to move between the upper electrode and the lower electrode.

[0010] Furthermore, the lower limit of movement of the triggering electrode is the lower dead point, and the upper limit of movement is the upper dead point;

[0011] The bottom dead point is the position where the distance between the needle tip of the needle electrode and the micron filament brush on the lower electrode is 3-5 mm;

[0012] The upper dead point is when the needle tip of the needle electrode is immersed in the micron-fine wire brush of the upper electrode; at the upper dead point, the needle electrode cannot protrude below the wire electrode of the upper electrode; the upward and downward movement of the triggering electrode can be manual or electric.

[0013] Furthermore, the embedding density of the conductive micron filament bundles is 4 bundles / cm 2 -16 bundles / cm 2 Each bundle of conductive micron wires contains 5-50 conductive micron wires, and each conductive micron wire has a diameter of 2μm-20μm and a length of 5mm-30mm.

[0014] Furthermore, the conductive substrate is one or more of a metal plate, a graphite plate, a carbon fiber plate or a carbon fiber felt; and the conductive micron filament bundle is one or two of alloy fiber and silicon carbide fiber.

[0015] Furthermore, the tip diameter of the needle electrode of the triggering electrode is 10 μm-50 μm, and the diameter of the needle tip of the triggering electrode is 10 μm-50 μm. 2 The conductive substrate corresponds to at least one needle tip of the needle-shaped electrode.

[0016] Furthermore, the conductive support of the initiating electrode is selected from one or more of a metal support, a graphite support or a carbon fiber support; and the needle-shaped electrode is made of one or both of stainless steel or titanium alloy.

[0017] Furthermore, the housing is provided with an air inlet and an air outlet. The gases introduced into the air inlet are H2 and CO2; the gases discharged from the air outlet are H2, CO2, H2O(g) and CO. The housing of the device is made of stainless steel or titanium alloy, preferably stainless steel, and its main function is to support the plasma reactor and act as a grounding electrode.

[0018] Furthermore, the device is also equipped with a power supply with adjustable voltage, and the positive and negative terminals of the power supply are connected to the upper electrode and the lower electrode by wiring terminals.

[0019] Furthermore, the power supply is selected from at least any one of a direct current power supply, a medium frequency alternating current power supply or a pulse power supply, and the output voltage range of the power supply is 0-10 kV, and the output power range is 0.5-500 kW.

[0020] The present invention also provides an application of a large-space high-density discharge plasma device, comprising the following steps:

[0021] a. When the operation starts, the needle tip of the initiating electrode is pushed to the lower dead point. At this time, the needle tip on the initiating electrode maintains the minimum distance with the filamentary line on the lower electrode. Then, the power supply is turned on and the voltage is gradually increased to generate filamentary discharge between the two.

[0022] b. When the discharge reaches a stable state and maintains a certain intensity (generally 10 kV), the triggering electrode is slowly pulled upward to gradually increase the distance between the needle tip and the micron-fine brush of the lower electrode, and the voltage of the power supply (9) is simultaneously increased to gradually extend the discharge space upward;

[0023] c When the trigger electrode is pulled to the top dead center, its needle tip is immersed in the micron-thin wire brush of the upper electrode. At this time, the discharge extends to the entire area between the upper and lower electrodes. The energy density of the generated plasma is adjusted by adjusting the voltage of the power supply.

[0024] dWhen shutdown is required, simply turn off the power supply, maintain ventilation, and lower the reactor temperature to below 100°C to shut down the system.

[0025] The present invention also provides the application of large space high density discharge plasma device in the fields of material processing, energy and environmental protection, such as coupling the large space discharge high density discharge plasma discharge device with catalytic materials to directly act on the VOCs degradation or CO2 reduction gas to be treated.

[0026] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0027] (1) The present invention proposes a discharge plasma device composed of a movable micron-sized filamentary brush electrode and a matching discharge initiation electrode, which combines the advantages of low-temperature plasma and arc discharge, and realizes low initiation voltage and high-intensity uniform discharge in a large space by controlling the electrode spacing. The present invention can generate plasma discharge with high energy density at a low voltage of 0-10kV.

[0028] (2) Since a large number of micron-sized conductor or semiconductor filaments are distributed inside the electrode of the device of the present invention, the local electric field near the electrode is extremely high at a relatively low voltage, and local corona discharge is easily generated. In order to obtain a discharge in a larger space, the distance between the electrode pairs is relatively large, and it is difficult to induce discharge using a low voltage. Therefore, the device is also designed with a movable multi-needle initiation unit that is connected to one of the electrodes. After the power is turned on, the needle-shaped part of the initiation unit is moved to the vicinity of the filament of the other electrode, which is equivalent to reducing the distance between the two electrodes to the minimum. At this time, the discharge between the needle tip and the filament will be triggered, and then the initiation unit will be gradually withdrawn, and the discharge current will be gradually stretched to the other electrode until the discharge is carried out between the filaments of the two fixed electrodes, thereby forming a uniform discharge in a larger space. In this way, a multi-purpose plasma generating device with a wide adjustable range of discharge energy density and a large space can be obtained.

[0029] (3) The present invention realizes uniform discharge in a large space through a movable multi-needle initiation unit, providing a basic condition for improving the efficient arc induction of plasma.

[0030] (4) The device of the present invention can obtain a multi-purpose plasma generating device with a wide adjustable range of discharge energy density and a large space, which can efficiently trigger chemical reactions such as VOCs degradation and CO2 reduction conversion.

[0031] (5) The device of the present invention has a simple structure, which is conducive to maintaining the large-space high-density discharge performance of plasma and avoiding problems such as excessive energy concentration and severe electrode ablation. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the structure of the plasma device of the present invention;

[0033] Figure 2 Schematic diagram of the working steps of the plasma device of the present invention.

[0034] Description of the markings in the figure:

[0035] 1-upper electrode, 2-lower electrode, 3-initiating electrode, 4-housing, 5-air inlet, 6-air outlet, 7-conductive substrate, 8-conductive micron wire bundle, 9-power supply, 10-conductive bracket;

[0036] A-starting stage, B-ignition stage, C-arcing stage, D-normal operation. DETAILED DESCRIPTION

[0037] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0038] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0039] In conjunction with the accompanying drawings, some embodiments of the present invention are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments may be combined with each other.

[0040] In the following embodiments, if there is no special description of raw materials or processing technology, it means that they are all conventional commercially available raw materials or conventional processing technologies in the field. If there is no special description of functional components or structures, it means that they are all conventional components or conventional structures used in the field to achieve corresponding functions.

[0041] The present invention provides a large space high density discharge plasma device, such as Figure 1 As shown, it includes a shell 4, and an upper electrode 1, a lower electrode 2 and an initiating electrode 3 located inside the shell 4; it is also equipped with a voltage-adjustable power supply 9, which is connected to the upper electrode 1 and the lower electrode 2 respectively.

[0042] The upper electrode 1 and the lower electrode 2 are electrodes with micron fine wire brushes, including a conductive substrate 7 and a conductive micron wire bundle 8 embedded in the conductive substrate 7; the embedding density of the conductive micron wire bundle 8 is 4 bundles / cm 2 -16 bundles / cm 2 Each bundle of conductive micron filaments 8 contains 5-50 conductive micron filaments, each conductive micron filament has a diameter of 2μm-20μm and a length of 5mm-30mm. The conductive substrate 7 is one or more of a metal plate, a graphite plate, a carbon fiber plate or a carbon fiber felt; the conductive micron filament bundle 8 is one or two of alloy fiber and silicon carbide fiber.

[0043] The triggering electrode 3 is a movable electrode with multiple needle tips, including a conductive support 10 and a needle electrode embedded thereon, one end of the needle electrode passes through the upper electrode 1 and is fixed on the conductive support 10, and the other end is suspended above the lower electrode 2; the conductive support 10 moves up and down, driving the needle electrode to move between the upper electrode 1 and the lower electrode 2. The lower limit of the movement of the triggering electrode 3 is the lower stop point, and the upper limit of the movement is the upper stop point; the lower stop point is the position where the distance between the needle tip of the needle electrode and the micron fine brush on the lower electrode 2 is 3-5mm; the upper stop point is the needle tip of the needle electrode is immersed in the micron fine brush of the upper electrode 1; at the upper stop point, the needle electrode cannot protrude below the filament electrode of the upper electrode 1; the up and down movement of the triggering electrode can be manual or electric.

[0044] The tip diameter of the needle electrode of the triggering electrode 3 is 10 μm-50 μm, and the diameter of the needle tip of the triggering electrode 3 is 10 μm-50 μm. 2 The conductive substrate 7 corresponds to at least one needle tip of the needle electrode. The conductive support of the triggering electrode is selected from one or more of a metal support, a graphite support or a carbon fiber support; the needle electrode is made of one or both of stainless steel and titanium alloy.

[0045] The housing 4 is provided with an air inlet 5 and an air outlet 6. The gases introduced into the air inlet 5 are H2 and CO2; the gases discharged from the air outlet 6 are H2, CO2, H2O(g) and CO. The housing of the device is made of stainless steel or titanium alloy, preferably stainless steel, and its main function is to support the plasma reactor and act as a grounding electrode.

[0046] The power supply 9 is selected from at least any one of a DC power supply, a medium frequency AC power supply or a pulse power supply. The output voltage range of the power supply 9 is 0-10 kV, and the output power range is 0.5-500 kW.

[0047] The above device operates as follows Figure 2 As shown, it includes A-starting stage, B-ignition stage, C-arcing stage, and D-normal operation. The specific steps are as follows:

[0048] a. Several conductive supports 10 of the initiating electrode 3 and a plurality of needle-shaped electrodes embedded thereon respectively pass through the holes on the upper electrode 1 and enter the interval between the upper electrode 1 and the lower electrode 2;

[0049] b. When the operation starts, the needle tip of the initiating electrode 3 is first pushed to the lower dead point, at which time the needle tip on the initiating electrode 3 and the filamentary line on the lower electrode 2 maintain a minimum distance, and then the power supply 9 is turned on and the voltage is gradually increased to generate filamentary discharge between the two;

[0050] c. When the above discharge reaches stability and maintains a certain intensity (generally 10 kV), slowly pull up the triggering electrode 3 to gradually increase the distance between the needle tip and the micron fine wire brush of the lower electrode 2, and simultaneously increase the voltage of the power supply 9 to gradually extend the discharge space upward;

[0051] d When the triggering electrode 3 is pulled to the top dead center, its needle tip is immersed in the micron-fine wire brush of the upper electrode 1. At this time, the discharge extends to the entire area between the upper and lower electrodes. The energy density of the generated plasma is adjusted by adjusting the voltage of the power supply 9.

[0052] eWhen shutdown is required, simply turn off the power supply, maintain ventilation, and lower the reactor temperature to below 100°C to shut down the system.

[0053] The following embodiments are all based on the above structure and operation method for reaction, as follows:

[0054] Example 1

[0055] In this embodiment, the upper electrode 1 and the lower electrode 2 are both composed of a conductive substrate 7 and a conductive micron wire bundle 8 embedded in the substrate. The embedding density of the conductive micron wire bundle 8 is 4 bundles / cm 2 Each bundle of conductive micron wires 8 includes 5 conductive micron wires, each conductive micron wire has a diameter of 20 μm and a length of 5 mm; the conductive substrate 7 is a metal plate, and the conductive micron wire bundles 8 are alloy fibers.

[0056] The triggering electrode 3 is composed of 20 conductive brackets 10 and needle-shaped electrodes embedded thereon. Each conductive bracket is embedded with 10 needle-shaped electrodes, and the diameter of the needle tip of each needle-shaped electrode is 50 μm. 2 The conductive substrate 7 corresponds to the tips of the 7 needle-shaped electrodes on the initiating electrode 3; the conductive support of the initiating electrode 3 is a metal support; and the needle-shaped electrodes are made of stainless steel.

[0057] In this embodiment, the lower limit of the movement of the initiating electrode 3 is the lower stop point, and the upper limit of the movement is the upper stop point; the lower stop point is the position where the distance between the tip of the needle electrode and the micron-fine wire brush on the lower electrode 2 is 3 mm; the upper stop point is the position where the tip of the needle electrode is immersed in the micron-fine wire brush of the upper electrode 1; at the upper stop point, the needle electrode cannot protrude below the filament electrode of the upper electrode 1, and the distance between the upper stop point and the lower stop point is 20 mm; the up and down movement of the initiating electrode is manual; the discharge of the plasma device is stable and maintains a certain intensity (generally 10 kV).

[0058] The power supply 9 is a DC power supply with an output voltage of 50V and an output power of 0.5kW.

[0059] The device shell is made of stainless steel or titanium alloy, preferably stainless steel, and its main function is to support the plasma reactor and serve as a grounding electrode.

[0060] Example 2

[0061] In this embodiment, the upper electrode 1 and the lower electrode 2 are both composed of a conductive substrate 7 and a conductive micron wire bundle 8 embedded in the substrate. The embedding density of the conductive micron wire bundle 8 is 8 bundles / cm 2 Each bundle of conductive micron wires 8 includes 10 conductive micron wires, each conductive micron wire has a diameter of 15 μm and a length of 10 mm; the conductive substrate 7 is a graphite plate, and the conductive micron wire bundle 8 is an alloy fiber.

[0062] The triggering electrode 3 is composed of 20 conductive brackets 10 and needle-shaped electrodes embedded thereon. Each conductive bracket is embedded with 10 needle-shaped electrodes, and the diameter of the needle tip of each needle-shaped electrode is 45 μm. 2 The conductive substrate 7 corresponds to the tips of the 7 needle-shaped electrodes on the initiating electrode 3; the conductive support of the initiating electrode 3 is a metal support; and the needle-shaped electrodes are made of stainless steel.

[0063] In this embodiment, the lower limit of the movement of the initiating electrode 3 is the lower stop point, and the upper limit of the movement is the upper stop point; the lower stop point is the position where the distance between the tip of the needle electrode and the micron-fine wire brush on the lower electrode 2 is 3 mm; the upper stop point is the position where the tip of the needle electrode is immersed in the micron-fine wire brush of the upper electrode 1; at the upper stop point, the needle electrode cannot protrude below the filament electrode of the upper electrode 1, and the distance between the upper stop point and the lower stop point is 20 mm; the up and down movement of the initiating electrode is manual; the discharge of the plasma device is stable and maintains a certain intensity (generally 10 kV).

[0064] The power supply 9 is a DC power supply with an output voltage of 100V and an output power of 1kW.

[0065] The device shell is made of stainless steel or titanium alloy, preferably stainless steel, and its main function is to support the plasma reactor and serve as a grounding electrode.

[0066] Example 3

[0067] In this embodiment, the upper electrode 1 and the lower electrode 2 are both composed of a conductive substrate 7 and a conductive micron filament bundle 8 embedded in the substrate. The embedding density of the conductive micron filament bundle 8 is 10 bundles / cm 2 Each bundle of conductive micron filaments 8 includes 20 conductive micron filaments, each conductive micron filament has a diameter of 10 μm and a length of 15 mm; the conductive substrate 7 is a graphite plate, and the conductive micron filament bundle 8 is silicon carbide fiber.

[0068] The triggering electrode 3 is composed of 20 conductive brackets 10 and needle-shaped electrodes embedded thereon. Each conductive bracket is embedded with 10 needle-shaped electrodes, and the diameter of the needle tip of each needle-shaped electrode is 40 μm. 2 The conductive substrate 7 corresponds to the tips of the 7 needle-shaped electrodes on the initiating electrode 3; the conductive support of the initiating electrode 3 is a metal support; and the needle-shaped electrodes are made of stainless steel.

[0069] In this embodiment, the lower limit of the movement of the initiating electrode 3 is the lower stop point, and the upper limit of the movement is the upper stop point; the lower stop point is the position where the distance between the needle tip of the needle electrode and the micron fine wire brush on the lower electrode 2 is 4 mm; the upper stop point is the position where the needle tip of the needle electrode is immersed in the micron fine wire brush of the upper electrode 1; at the upper stop point, the needle electrode cannot protrude below the filament electrode of the upper electrode 1, and the distance between the upper stop point and the lower stop point is 20 mm; the up and down movement of the initiating electrode is manual; the discharge of the plasma device is stable and maintains a certain intensity (generally 10 kV).

[0070] The power supply 9 is a medium frequency AC power supply with an output voltage of 5 kV and an output power of 100 kW.

[0071] The device shell is made of stainless steel or titanium alloy, preferably stainless steel, and its main function is to support the plasma reactor and serve as a grounding electrode.

[0072] Example 4

[0073] In this embodiment, the upper electrode 1 and the lower electrode 2 are both composed of a conductive substrate 7 and a conductive micron filament bundle 8 embedded in the substrate. The embedding density of the conductive micron filament bundle 8 is 12 bundles / cm 2 Each bundle of conductive micron wires 8 includes 30 conductive micron wires, each conductive micron wire has a diameter of 5 μm and a length of 20 mm; the conductive substrate 7 is a graphite plate, and the conductive micron wire bundle 8 is an alloy fiber.

[0074] The triggering electrode 3 is composed of 20 conductive brackets 10 and needle-shaped electrodes embedded thereon. Each conductive bracket is embedded with 10 needle-shaped electrodes, and the diameter of the needle tip of each needle-shaped electrode is 30 μm. 2 The conductive substrate 7 corresponds to the tips of the 7 needle-shaped electrodes on the initiating electrode 3; the conductive support of the initiating electrode 3 is a metal support; and the needle-shaped electrodes are made of stainless steel.

[0075] In this embodiment, the lower limit of the movement of the initiating electrode 3 is the lower stop point, and the upper limit of the movement is the upper stop point; the lower stop point is the position where the distance between the needle tip of the needle electrode and the micron fine wire brush on the lower electrode 2 is 4 mm; the upper stop point is the position where the needle tip of the needle electrode is immersed in the micron fine wire brush of the upper electrode 1; at the upper stop point, the needle electrode cannot protrude below the filament electrode of the upper electrode 1, and the distance between the upper stop point and the lower stop point is 20 mm; the up and down movement of the initiating electrode is manual; the discharge of the plasma device is stable and maintains a certain intensity (generally 10 kV).

[0076] The power supply 9 is a medium frequency AC power supply with an output voltage of 10 kV and an output power of 500 kW.

[0077] The device shell is made of stainless steel or titanium alloy, preferably stainless steel, and its main function is to support the plasma reactor and serve as a grounding electrode.

[0078] Example 5

[0079] In this embodiment, the upper electrode 1 and the lower electrode 2 are both composed of a conductive substrate 7 and a conductive micron wire bundle 8 embedded in the substrate. The embedding density of the conductive micron wire bundle 8 is 14 bundles / cm 2 Each bundle of conductive micron wires 8 contains 40 conductive micron wires, each conductive micron wire has a diameter of 3 μm and a length of 25 mm; the conductive substrate 7 is a metal plate, and the conductive micron wire bundle 8 is silicon carbide fiber.

[0080] The triggering electrode 3 is composed of 20 conductive brackets 10 and needle-shaped electrodes embedded thereon. Each conductive bracket is embedded with 10 needle-shaped electrodes, and the diameter of the needle tip of each needle-shaped electrode is 20 μm. 2 The conductive substrate 7 corresponds to the tips of the 7 needle-shaped electrodes on the initiating electrode 3; the conductive support of the initiating electrode 3 is a metal support; and the needle-shaped electrodes are made of stainless steel.

[0081] In this embodiment, the lower limit of the movement of the initiating electrode 3 is the lower stop point, and the upper limit of the movement is the upper stop point; the lower stop point is the position where the distance between the needle tip of the needle electrode and the micron fine wire brush on the lower electrode 2 is 5 mm; the upper stop point is the position where the needle tip of the needle electrode is immersed in the micron fine wire brush of the upper electrode 1; at the upper stop point, the needle electrode cannot protrude below the filament electrode of the upper electrode 1, and the distance between the upper stop point and the lower stop point is 20 mm; the up and down movement of the initiating electrode is manual; the discharge of the plasma device is stable and maintains a certain intensity (generally 10 kV).

[0082] The power supply 9 is a pulse power supply with an output voltage of 5 kV and an output power of 10 kW.

[0083] The device shell is made of stainless steel or titanium alloy, preferably stainless steel, and its main function is to support the plasma reactor and serve as a grounding electrode.

[0084] Example 6

[0085] In this embodiment, the upper electrode 1 and the lower electrode 2 are both composed of a conductive substrate 7 and a conductive micron filament bundle 8 embedded in the substrate. The embedding density of the conductive micron filament bundle 8 is 16 bundles / cm 2 Each bundle of conductive micron wires 8 contains 50 conductive micron wires, each conductive micron wire has a diameter of 2 μm and a length of 30 mm; the conductive substrate 7 is a metal plate, and the conductive micron wire bundle 8 is silicon carbide fiber.

[0086] The triggering electrode 3 is composed of 20 conductive brackets 10 and needle-shaped electrodes embedded thereon. Each conductive bracket is embedded with 10 needle-shaped electrodes, and the diameter of the needle tip of each needle-shaped electrode is 10 μm. 2 The conductive substrate 7 corresponds to the tips of the 7 needle-shaped electrodes on the initiating electrode 3; the conductive support of the initiating electrode 3 is a metal support; and the needle-shaped electrodes are made of stainless steel.

[0087] In this embodiment, the lower limit of the movement of the initiating electrode 3 is the lower stop point, and the upper limit of the movement is the upper stop point; the lower stop point is the position where the distance between the needle tip of the needle electrode and the micron fine wire brush on the lower electrode 2 is 5 mm; the upper stop point is the position where the needle tip of the needle electrode is immersed in the micron fine wire brush of the upper electrode 1; at the upper stop point, the needle electrode cannot protrude below the filament electrode of the upper electrode 1, and the distance between the upper stop point and the lower stop point is 20 mm; the up and down movement of the initiating electrode is manual; the discharge of the plasma device is stable and maintains a certain intensity (generally 10 kV).

[0088] The power supply 9 is a pulse power supply with an output voltage of 10 kV and an output power of 50 kW.

[0089] The device shell is made of stainless steel or titanium alloy, preferably stainless steel, and its main function is to support the plasma reactor and serve as a grounding electrode.

[0090] The reaction conditions of Examples 1 to 6 are summarized in Table 1.

[0091] Table 1 Experimental conditions of Examples 1 to 6 are as follows:

[0092]

[0093] The performance of the devices of the above embodiments is as follows:

[0094] Table 2 Performance of large space high density discharge plasma generator in Examples 1 to 6

[0095]

[0096] From Table 2 above, it can be seen that the large-space high-density discharge plasma generating device provided by the present invention can generate a low-temperature plasma with a maximum density of (1.8×10 15 m -3 ), the arc that can be generated (2×10 6 V / m), can meet the needs of (CO2 and VOCs degradation), combines the advantages of low-temperature plasma and arc discharge, and has the characteristics of (large space and high-density discharge).

[0097] The large-space high-density discharge plasma device provided by the present invention can be used in the fields of material processing, energy, and environmental protection. The following is an example of CO2 reduction conversion and VOCs degradation:

[0098] The device obtained in the above-mentioned Examples 1-6 is applied to CO2 reduction conversion, and the specific method is as follows:

[0099] a A mixed gas of H2 and CO2 with a volume ratio of 3:1 is input into the shell from the gas inlet 5 at a flow rate of 50 mL / min.

[0100] b. When the operation starts, the needle tip of the initiating electrode 3 is first pushed to the lower dead point, at which time the needle tip on the initiating electrode 3 and the filamentary line on the lower electrode 2 maintain a minimum distance, and then the power supply 9 is turned on and the voltage is gradually increased to generate filamentary discharge between the two;

[0101] c. When the discharge reaches stability and maintains 10 kV, slowly pull up the triggering electrode 3 to gradually increase the distance between the needle tip and the micron fine brush of the lower electrode 2, and simultaneously increase the voltage of the power supply 9 to gradually extend the discharge space upward;

[0102] d When the triggering electrode 3 is pulled to the top dead center, its needle tip is immersed in the micron-fine wire brush of the upper electrode 1. At this time, the discharge extends to the entire area between the upper and lower electrodes. The energy density of the generated plasma is adjusted by adjusting the voltage of the power supply 9.

[0103] eWhen shutdown is required, the power supply can be directly turned off, ventilation is maintained, and the reactor temperature is reduced to below 100°C to shut down the system. The device obtained in the above Examples 1-6 is applied to VOCs degradation, and the method is the same as above. Air containing VOCs is input from the air inlet 5 to the shell, wherein the VOCs content is about 50ppm, the flow rate is 100mL / min, and the rest of the method is the same as above. The results are shown in Table 3 below:

[0104] Table 3 Performance of CO2 reduction conversion and VOCs degradation induced by large space high density discharge plasma generator in Examples 1 to 6

[0105] <![CDATA[CO2 reduction and conversion efficiency]]> VOCs degradation efficiency Example 1 2.32％ 85.9％ Example 2 11.01％ 89.2.5％ Example 3 34.50％ 92.4％ Example 4 53.45％ 94.6％ Example 5 62.38％ 98.9％ Example 6 62.92％ 99.1％

[0106] From Table 3 above, it can be seen that in a large-space high-density discharge plasma generating device provided by the present invention, as the electrode spacing increases and the conductive micron wire diameter decreases, the arc discharge intensity and energy density increase, thereby increasing the CO2 reduction conversion efficiency and the VOCs degradation efficiency.

[0107] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A large-space high-density discharge plasma device, comprising a housing (4), and an upper electrode (1), a lower electrode (2) and an initiating electrode (3) located inside the housing (4); characterized in that: The upper electrode (1) and the lower electrode (2) are both electrodes with micron fine wire brushes, comprising a conductive substrate (7) and a conductive micron wire bundle (8) embedded on the conductive substrate (7); The triggering electrode (3) is a movable electrode with multiple needle tips, comprising a conductive support (10) and a needle-shaped electrode embedded thereon, wherein one end of the needle-shaped electrode passes through the upper electrode (1) and is fixed on the conductive support (10), and the other end is suspended above the lower electrode (2); the conductive support (10) moves up and down, driving the needle-shaped electrode to move between the upper electrode (1) and the lower electrode (2).

2. A large space high density discharge plasma device according to claim 1, characterized in that: The lower limit of movement of the initiating electrode (3) is the lower dead point, and the upper limit of movement is the upper dead point; The lower dead point is the position where the distance between the needle tip of the needle electrode and the micron fine brush on the lower electrode (2) is 3-5 mm; The top dead point is when the needle tip of the needle-shaped electrode is immersed in the micron-fine wire brush of the upper electrode (1).

3. A large space high density discharge plasma device according to claim 1, characterized in that: The embedding density of the conductive micron filament bundles (8) is 4 bundles / cm 2 -16 bundles / cm 2 Each bundle of conductive micron wires (8) contains 5-50 conductive micron wires, and each conductive micron wire has a diameter of 2 μm-20 μm and a length of 5 mm-30 mm.

4. A large space high density discharge plasma device according to claim 1, characterized in that: The conductive substrate (7) is one or more of a metal plate, a graphite plate, a carbon fiber plate or a carbon fiber felt; the conductive micron fiber bundle (8) is one or both of alloy fibers and silicon carbide fibers.

5. A large space high density discharge plasma device according to claim 1, characterized in that: The tip diameter of the needle-shaped electrode of the triggering electrode (3) is 10 μm-50 μm, and the diameter of the needle-shaped electrode is 10 μm-50 μm. 2 The conductive substrate (7) corresponds to at least one needle tip of a needle-shaped electrode.

6. A large space high density discharge plasma device according to claim 1, characterized in that: The housing (4) is provided with an air inlet (5) and an air outlet (6).

7. A large space high density discharge plasma device according to claim 1, characterized in that: The device is also equipped with a voltage-adjustable power supply (9), which is respectively connected to the upper electrode (1) and the lower electrode (2).

8. A large space high density discharge plasma device according to claim 7, characterized in that: The power supply (9) is selected from at least any one of a direct current power supply, a medium frequency alternating current power supply or a pulse power supply.

9. A large space high density discharge plasma device according to claim 7, characterized in that: The power supply (9) has an output voltage range of 0-10 kV and an output power range of 0.5-500 kW.

10. An application of a large space high density discharge plasma device as claimed in any one of claims 1 to 9, characterized in that: The following steps are involved: a. When the operation starts, the needle tip of the triggering electrode (3) is first pushed to the bottom dead center, the power supply (9) is turned on and the voltage is gradually increased to generate a filamentary discharge between the two; b. When the discharge reaches stability, the triggering electrode (3) is pulled up, so that the distance between the needle tip and the micron-fine brush of the lower electrode (2) gradually increases, and the power supply (9) voltage is simultaneously increased, so that the discharge space gradually extends upward; c. When the trigger electrode (3) is pulled to the top dead center, its needle tip is immersed in the micron-fine wire brush of the upper electrode (1). At this time, the discharge extends to the entire area between the upper and lower electrodes, and the energy density of the generated plasma is adjusted by adjusting the voltage of the power supply (9).

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