A large-space high-density discharge plasma device and application thereof

Abstract

The application 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 combined by a movable micron-sized filament brush electrode and a matched discharge initiation electrode, and has the advantages of low-temperature plasma and arc discharge. By controlling the distance between the electrodes, high-intensity uniform discharge in a large space under low initiation voltage is realized. Compared with the prior art, the plasma device has the advantages of wide adjustable range of discharge energy density, large space and multiple uses.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of material processing, energy and environmental protection, and particularly relates to a large-space high-density discharge plasma device and application thereof. BACKGROUND

[0002] Plasma activates gas molecules through ionization, excitation and dissociation, and generates a large number of active species, thereby generating high-density electrons. According to the difference in gas pressure, plasma is divided into low-pressure (<10 Torr) plasma, medium-pressure (10-100 Torr) plasma and high-pressure (>100 Torr) plasma; according to the difference in temperature, plasma is divided into thermal plasma and non-thermal plasma.

[0003] Conventional low-temperature discharge plasma refers to the temperature of electrons generated by gas at about one atmosphere (>10 4K) Far higher than the ion temperature (= 300 ~ 500K) of the plasma, so it can maintain the discharge balance at low energy consumption. Conventional low-temperature discharge plasma is commonly used in material surface treatment and modification, and carbon reduction and other fields. For example, in order to solve the problem of insufficient adhesion of polytetrafluoroethylene (PTFE) material which has been widely used in medical, aerospace, electronics and other industries, patent application CN116836443A discloses a method for modifying the surface of PTFE by using argon or argon-containing mixed gas plasma to modify the structure of PTFE and solve the problem of insufficient adhesion of PTFE. In addition, patent application CN117116747A discloses a method for treating surface traps and dangling bonds of silicon carbide in the semiconductor field by using argon and ammonia mixed plasma to improve the flatness of the surface of silicon carbide. Patent application CN117142433A discloses a method for adding a Ni-based catalyst in a DBD plasma reactor to perform CO2 and VOCs (alkanes, alkenes, alcohols, benzene series, etc.) collaborative resource treatment at normal temperature and pressure, which improves the selectivity of different products of carbon dioxide catalytic reforming and energy utilization efficiency. Patent application CN116676689A discloses a method for preparing spiral carbon fibers by arc discharge at atmospheric pressure, which can switch the growth conditions within a few seconds and control the spiral carbon fibers to be in different growth environments at different time periods, thereby enabling the spiral carbon fibers to have the ability to re-nucleate and grow on the surface, simplifying the growth difficulty of the spiral carbon fibers. The method utilizes the advantages of fast temperature switching and high temperature peak of arc discharge to prepare carbon fiber reinforced composites with isotropic mechanical properties which cannot be prepared by chemical vapor deposition. In summary, conventional low-temperature discharge plasma has been widely used in material surface treatment and modification, and carbon reduction and other fields. However, due to the low energy density and limited chemical reaction capacity of conventional low-temperature discharge plasma, its large-scale use is limited.

[0004] Arc is a common thermal plasma that can produce a strong brightness arc column with strong current density (about 10 3 A / cm 2 ) under a low inter-electrode voltage (about tens of volts), and the temperature in the channel and on the electrode is about 7000 ~ 8000℃. Due to the high temperature generated, arc discharge can be applied to process high-temperature materials. Patent CN118175710A provides a plasma generating device and a method for preparing industrial raw materials by plasma, which improves a method for efficiently preparing low-temperature plasma and generating arc. However, this patent cannot meet the needs of high-density discharge plasma in a large space.

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

[0006] The present application aims to overcome the defects of the prior art and provides a large space high-density discharge plasma device and its application. The discharge plasma device is composed of a movable micron-sized filament brush electrode and a matched discharge initiation electrode. The device combines the advantages of low-temperature plasma and arc discharge and realizes high-intensity uniform discharge in a large space at a low initiation voltage by controlling the distance between the electrodes.

[0007] The present application can be achieved by the following technical scheme: a large space high-density discharge plasma device, comprising a shell, an upper electrode, a lower electrode and an initiation electrode located inside the shell.

[0008] The upper electrode and the lower electrode are both electrodes with micron-sized filament brushes, comprising a conductive substrate and a conductive micron filament bundle embedded in the conductive substrate.

[0009] The initiation electrode is a movable electrode with multiple needle tips, comprising a conductive support and needle-shaped electrodes embedded thereon. One end of the needle-shaped electrodes penetrates the upper electrode and is fixed to the conductive support, and the other end is suspended above the lower electrode. The conductive support moves up and down, driving the needle-shaped electrodes to move between the upper electrode and the lower electrode.

[0010] Further, the lower limit of the movement of the initiation electrode is the lower stop point, and the upper limit of the movement is the upper stop point.

[0011] The lower stop point is the position where the needle tip of the needle-shaped electrode is 3-5 mm away from the micron-sized filament brush on the lower electrode.

[0012] The upper stop point is when the needle tip of the needle-shaped electrode is immersed in the micron-sized filament brush of the upper electrode. At the upper stop point, the needle-shaped electrode cannot protrude below the filament electrode of the upper electrode. The up-and-down movement of the initiation electrode can be manual or electric.

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

[0014] Further, the conductive substrate 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 is one or both of an alloy fiber and a silicon carbide fiber.

[0015] Further, the needle tip of the needle-shaped electrode of the initiation electrode has a diameter of 10-50 microns, and at least one needle tip of the needle-shaped electrode corresponds to each 1 cm 2 of the conductive substrate.

[0016] Further, the conductive support of the initiation 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 or titanium alloy.

[0017] Further, the housing is provided with an air inlet and an air outlet. The air inlet is connected to H2 and CO2; the air outlet is connected to H2, CO2, H2O(g) and CO. The material of the housing is stainless steel or titanium alloy, preferably stainless steel, which mainly serves to support the plasma reactor and act as a grounding electrode.

[0018] Further, the device is also provided with a voltage-adjustable power supply, and the positive and negative terminals of the power supply are connected to the upper electrode and the lower electrode through terminal connectors.

[0019] Further, the power supply is selected from at least 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 0-10kV, and the output power range is 0.5-500kW.

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

[0021] a When starting operation, the needle tip of the initiation electrode is first pushed to the lower dead point, at which time the needle tip on the initiation electrode maintains the minimum distance with the filament wire on the lower electrode, then the power supply is turned on and the voltage is gradually increased to generate filament discharge between the two;

[0022] b When the discharge reaches a stable state and maintains a certain intensity (generally 10kV), the initiation electrode is slowly pulled up to gradually increase the distance between the needle tip and the micron-fine wire 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 initiation electrode is pulled to the upper dead point and the needle tip is immersed in the micron-fine wire brush of the upper electrode, at this time the discharge extends to the entire region between the upper and lower electrodes, and the plasma energy density is adjusted by adjusting the voltage of the power supply.

[0024] d When shutdown is needed, the power supply can be directly turned off, the ventilation is maintained, and the reactor temperature is reduced to below 100℃ to turn off the system.

[0025] The application also provides an application of the large-space high-density discharge plasma device in the fields of material processing, energy and environmental protection. For example, the large-space discharge high-density discharge plasma discharge device is coupled with catalytic materials to directly act on the VOCs to be treated or CO2 reduction gas.

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

[0027] (1) The present application proposes a discharge plasma device composed of movable micron-sized filamentous brush electrodes, and a matched 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 application can generate plasma discharge with high energy density at a low voltage of 0-10 kV.

[0028] (2) The present application device has a large number of micron-sized conductor or semiconductor filaments distributed inside the electrode, and a local electric field is extremely high near the filaments at a low voltage, so that local corona discharge is easily generated. In order to obtain discharge in a large space, the distance between the electrode pairs is large, and it is difficult to initiate discharge at a low voltage. Therefore, the present application device is also designed with a movable multi-needle initiation unit 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 filaments of the other electrode, which is equivalent to reducing the distance between the two electrodes to a minimum. At this time, the discharge between the initiation needle tip and the filaments is initiated, and then the initiation unit is gradually withdrawn, and the discharge current is gradually stretched to the other electrode, until the discharge is generated between the filaments of the two fixed electrodes. In this way, a multi-purpose plasma generation device with a wide range of adjustable discharge energy density and a large space is obtained.

[0029] (3) The present application realizes uniform discharge in a large space through the movable multi-needle initiation unit, and provides basic conditions for improving the efficient arc current of the plasma.

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

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

[0032] Figure 1 The figure is a schematic diagram of the structure of the plasma device of the present application;

[0033] Figure 2 The figure is a schematic diagram of the working steps of the plasma device of the present application.

[0034] MARK DESCRIPTION:

[0035] 1 - upper electrode, 2 - lower electrode, 3 - initiation electrode, 4 - shell, 5 - gas inlet, 6 - gas outlet, 7 - conductive base plate, 8 - conductive micron filament bundle, 9 - power supply, 10 - conductive support;

[0036] A - Initial stage, B - Ignition stage, C - Arcing stage, D - Normal operation. Detailed Implementation

[0037] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0038] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0039] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0040] In the following embodiments, unless otherwise specified, the raw materials or processing techniques are conventional commercially available raw materials or conventional processing techniques in the art. Unless otherwise specified, the functional components or structures are conventional components or conventional structures used in the art to achieve the corresponding functions.

[0041] This invention provides a large-space high-density discharge plasma device, such as... Figure 1 As shown, it includes a housing 4, and an upper electrode 1, a lower electrode 2 and an initiation electrode 3 located inside the housing 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] Both the upper electrode 1 and the lower electrode 2 are electrodes with micron-sized fine filament brushes, comprising a conductive substrate 7 and conductive micron-sized filament bundles 8 embedded on the conductive substrate 7; the embedding density of the conductive micron-sized filament bundles 8 is 4 bundles / cm. 2 -16 bundles / cm 2 Each conductive microfilament bundle 8 contains 5-50 conductive microfilaments, each with a diameter of 2μm-20μm and a length of 5mm-30mm. The conductive substrate 7 is one or more of a metal plate, graphite plate, carbon fiber plate, or carbon fiber felt; the conductive microfilament bundle 8 is one or two of alloy fiber and silicon carbide fiber.

[0043] The initiation electrode 3 is a movable electrode with multiple needle tips, including a conductive bracket 10 and needle electrodes embedded thereon, one end of the needle electrodes is fixed on the conductive bracket 10 and the other end is suspended above the lower electrode 2; the conductive bracket 10 moves up and down, driving the needle electrodes to move between the upper electrode 1 and the lower electrode 2. The lower limit of the movement of the initiation 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 needle tip of the needle electrode is 3-5mm away from the micron filament brush on the lower electrode 2; the upper stop point is that the needle tip of the needle electrode is immersed in the micron filament 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 initiation electrode can be manual or electric.

[0044] The needle tip diameter of the needle electrode of the initiation electrode 3 is 10-50μm, and there is at least one needle tip of the needle electrode corresponding to every 1cm 2 of the conductive substrate 7. The conductive bracket of the initiation electrode is selected from one or several of metal bracket, graphite bracket or carbon fiber bracket; the needle electrode uses one or both of stainless steel or titanium alloy.

[0045] The shell 4 is provided with an air inlet 5 and an air outlet 6. The gas entering the air inlet 5 is H2 and CO2; the gas flowing out of the air outlet 6 is H2, CO2, H2O(g) and CO. The material of the device shell is stainless steel or titanium alloy, preferably stainless steel, which mainly serves to support the plasma reactor and act as a grounding electrode.

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

[0047] The operation mode of the above device is as shown in Figure 2 , including A-starting stage, B-ignition stage, C-pulling arc stage, D-normal work, and the specific steps are as follows:

[0048] a several conductive brackets 10 of the initiation electrode 3 and the multiple needle electrodes embedded thereon pass through the holes in the upper electrode 1 and enter the interval between the upper electrode 1 and the lower electrode 2;

[0049] b when starting to operate, first push the needle tip part of the initiation electrode 3 to the lower stop point, at this time the needle tip on the initiation electrode 3 keeps the minimum distance with the filament line on the lower electrode 2, then turn on the power supply 9 and gradually increase the voltage to make the filament discharge between them;

[0050] cWhen the above discharge reaches a stable state and maintains a certain intensity (usually 10 kV), the initiating electrode 3 is slowly pulled up, the distance between the needle tip and the micron filament brush of the lower electrode 2 is gradually increased, and the voltage of the power supply 9 is simultaneously increased, so that the discharge space is gradually extended upward;

[0051] dWhen the initiating electrode 3 is pulled to the upper stop point and the needle tip is immersed in the micron filament brush of the upper electrode 1, the discharge extends to the entire region between the upper and lower electrodes at this time, and the plasma energy density generated is adjusted by adjusting the voltage of the power supply 9.

[0052] eWhen shutdown is required, the power supply can be directly turned off, the temperature of the reactor is reduced to below 100°C, and the system is turned off.

[0053] The following examples are based on the above structure and operation method for reaction, and the specific embodiments are 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 filament bundle 8 embedded in the substrate, and the embedding density of the conductive micron filament bundle 8 is 4 bundles / cm 2 Each conductive micron filament bundle 8 contains 5 conductive micron filaments, and each conductive micron filament has a diameter of 20 μm and a length of 5 mm; the conductive substrate 7 is a metal plate, and the conductive micron filament bundle 8 is an alloy fiber.

[0056] The initiating electrode 3 is composed of 20 conductive supports 10 and needle-shaped electrodes embedded thereon, and each conductive support has 10 needle-shaped electrodes embedded thereon, and each needle-shaped electrode has a needle tip with a diameter of 50 μm; each 1 cm 2 of the conductive substrate 7 corresponds to the needle tip of 7 needle-shaped electrodes of the initiating electrode 3; the conductive support of the initiating electrode 3 is a metal support; the needle-shaped electrode is 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 needle tip of the needle-shaped electrode is 3 mm away from the micron filament brush on the lower electrode 2; the upper stop point is the position where the needle tip of the needle-shaped electrode is immersed in the micron filament brush of the upper electrode 1; at the upper stop point, the needle-shaped 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-down movement of the initiating electrode is manual; the plasma device is discharged stably and maintains a certain intensity (usually 10 kV).

[0058] The power supply 9 is a direct current power supply, the output voltage of the power supply is 50 V, and the output power is 0.5 kW.

[0059] The material of the device shell is stainless steel or titanium alloy, preferably stainless steel, which mainly serves to support the plasma reactor and act 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 microwire bundle 8 embedded in the substrate. The embedding density of the conductive microwire bundle 8 is 8 bundles / cm 2 Each conductive microwire bundle 8 contains 10 conductive microwires, each with a diameter of 15 μm and a length of 10 mm. The conductive substrate 7 is a graphite plate, and the conductive microwire bundle 8 is an alloy fiber.

[0062] The initiation electrode 3 is composed of 20 conductive supports 10 and needle-shaped electrodes embedded on them. Each conductive support has 10 needle-shaped electrodes embedded on it, each with a needle tip diameter of 45 μm. There are 7 needle tips of the needle-shaped electrodes of the initiation electrode 3 corresponding to each 1 cm 2 of the conductive substrate 7. The conductive supports of the initiation electrode 3 are metal supports, and the needle-shaped electrodes are made of stainless steel.

[0063] In this embodiment, the lower limit of the movement of the initiation electrode 3 is the lower stop point, and the upper limit is the upper stop point. The lower stop point is the position where the needle tip of the needle-shaped electrode is 3 mm away from the microwire brush on the lower electrode 2. The upper stop point is when the needle tip of the needle-shaped electrode is submerged in the microwire brush of the upper electrode 1. At the upper stop point, the needle-shaped electrode cannot protrude below the filament electrode of the upper electrode 1. The distance between the upper stop point and the lower stop point is 20 mm. The up and down movement of the initiation electrode is manual. The plasma device discharges stably and maintains a certain intensity (usually 10 kV).

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

[0065] The material of the device shell is stainless steel or titanium alloy, preferably stainless steel, which mainly serves to support the plasma reactor and act 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 microwire bundle 8 embedded in the substrate. The embedding density of the conductive microwire bundle 8 is 10 bundles / cm 2 Each conductive microwire bundle 8 contains 20 conductive microwires, each with a diameter of 10 μm and a length of 15 mm. The conductive substrate 7 is a graphite plate, and the conductive microwire bundle 8 is a silicon carbide fiber.

[0068] The initiation electrode 3 is composed of 20 conductive supports 10 and needle electrodes embedded thereon, 10 needle electrodes are embedded on each conductive support, the tip diameter of each needle electrode is 40 μm; 7 tip of needle electrodes on the conductive substrate 7 per 1 cm 2 corresponds to the tip of needle electrodes on the initiation electrode 3; the conductive support of the initiation electrode 3 is a metal support; the needle electrode uses stainless steel.

[0069] In the embodiment, the lower limit of the movement of the initiation 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 tip of the needle electrode is 4 mm away from the micron filament brush on the lower electrode 2; the upper stop point is that the tip of the needle electrode is immersed in the micron filament 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 distance between the upper stop point and the lower stop point is 20 mm; the up and down movement of the initiation 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 alternating current power supply, the output voltage of the power supply is 5 kV, and the output power is 100 kW.

[0071] The material of the device shell is stainless steel or titanium alloy, preferably stainless steel, which mainly supports the plasma reactor and serves as a grounding electrode.

[0072] Embodiment 4

[0073] In the 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 on the substrate, the embedding density of the conductive micron filament bundle 8 is 12 bundles / cm 2 , each conductive micron filament bundle 8 contains 30 conductive microns, and each conductive micron has a diameter of 5 μm and a length of 20 mm; the conductive substrate 7 is a graphite plate, and the conductive micron filament bundle 8 is an alloy fiber.

[0074] The initiation electrode 3 is composed of 20 conductive supports 10 and needle electrodes embedded thereon, 10 needle electrodes are embedded on each conductive support, the tip diameter of each needle electrode is 40 μm; 7 tip of needle electrodes on the conductive substrate 7 per 1 cm 2 corresponds to the tip of needle electrodes on the initiation electrode 3; the conductive support of the initiation electrode 3 is a metal support; the needle electrode uses stainless steel.

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

[0076] The power supply 9 is a medium-frequency alternating current power supply, the output voltage of the power supply is 10 kV, and the output power is 500 kW.

[0077] The material of the device shell is stainless steel or titanium alloy, preferably stainless steel, which mainly serves to support the plasma reactor and act as a grounding electrode.

[0078] Embodiment 5

[0079] In the 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 14 bundles / cm 2 ; each conductive micron filament bundle 8 contains 40 conductive microns, each conductive micron has a diameter of 3 μm and a length of 25 mm; the conductive substrate 7 is a metal plate, and the conductive micron filament bundle 8 is a silicon carbide fiber.

[0080] The initiating electrode 3 is composed of 20 conductive supports 10 and needle electrodes embedded on them; each conductive support has 10 needle electrodes embedded on it, and each needle electrode has a needle tip with a diameter of 20 μm; there are 7 needle tips of the needle electrodes of the initiating electrode 3 corresponding to each 1 cm 2 of the conductive substrate 7; the conductive supports of the initiating electrode 3 are metal supports; the needle electrodes are made of stainless steel.

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

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

[0083] The material of the device shell is stainless steel or titanium alloy, preferably stainless steel, which mainly serves to support the plasma reactor and act as a grounding electrode.

[0084] Example 6

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

[0086] The initiation electrode 3 is composed of 20 conductive supports 10 and needle-shaped electrodes embedded in the supports, with 10 needle-shaped electrodes embedded in each conductive support, and the tip diameter of each needle-shaped electrode is 10 μm; there are 7 tip points of the needle-shaped electrodes of the initiation electrode 3 corresponding to each 1 cm 2 of the conductive substrate 7; the conductive supports of the initiation electrode 3 are metal supports; and the needle-shaped electrodes are made of stainless steel.

[0087] In this embodiment, the lower limit of the movement of the initiation electrode 3 is the lower dead point, and the upper limit of the movement is the upper dead point; the lower dead point is the position where the tip of the needle-shaped electrode is 5 mm away from the microwire brush on the lower electrode 2; the upper dead point is the position where the tip of the needle-shaped electrode is immersed in the microwire brush of the upper electrode 1; at the upper dead point, the needle-shaped electrode cannot protrude below the filament electrode of the upper electrode 1; the distance between the upper dead point and the lower dead point is 20 mm; the up-and-down movement of the initiation electrode is manual; and 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 material of the device shell is stainless steel or titanium alloy, preferably stainless steel, which mainly serves to support the plasma reactor and act as a grounding electrode.

[0090] The reaction conditions of the above-mentioned Examples 1-6 are summarized in Table 1.

[0091] Table 1: The experimental conditions of Examples 1-6 are as follows:

[0092]

[0093] The performance of the device of each of the above-mentioned examples is as follows:

[0094] Table 2: The performance of the large-space high-density discharge plasma generating device in Examples 1-6

[0095]

[0096] From the above table 2, it can be seen that the large space high density discharge plasma generating device provided by the application can generate low temperature plasma with a density of up to (1.8 x 10 15 m -3 ), can generate arc (2 x 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 high density discharge).

[0097] The large space high density discharge plasma device provided by the application can be used in the fields of material processing, energy and environmental protection, etc. The following takes CO2 reduction conversion and VOCs degradation as examples for illustration:

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

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

[0100] b When starting to operate, the needle tip part of the initiation electrode 3 is first pushed to the lower dead point, at this time the needle tip on the initiation electrode 3 and the filament wire on the lower electrode 2 maintain the minimum distance, then the power supply 9 is turned on and the voltage is gradually increased, so that the filament discharge is generated between the two;

[0101] c When the above discharge reaches stability and maintains 10 kV, the initiation electrode 3 is slowly pulled up, so that the distance between the needle tip and the micron filament brush of the lower electrode 2 gradually increases, and the voltage of the power supply 9 is increased synchronously, so that the discharge space is gradually extended upward;

[0102] d When the initiation electrode 3 is pulled to the upper dead point, the needle tip is immersed in the micron filament brush of the upper electrode 1, at this time the discharge extends to the entire region between the upper and lower electrodes, and the plasma energy density generated is adjusted by adjusting the voltage of the power supply 9.

[0103] e When shutdown is needed, the power supply can be directly turned off, the ventilation is kept, the reactor temperature is reduced to below 100℃, and then the system is turned off. The device obtained in the above examples 1-6 is applied in VOCs degradation, and the method is the same as above. The air containing VOCs is input into the shell from the gas inlet 5, wherein the content of VOCs is about 50 ppm, and the flow rate is 100 mL / min, and the remaining methods are the same as above. The results are as follows in table 3:

[0104] Table 3 Performance table of the large space high density discharge plasma generating device in examples 1-6 for initiating CO2 reduction conversion and VOCs degradation

[0105] CO2 reduction 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 the above Table 3, it can be seen that the large-space high-density discharge plasma generating device provided by the application has the arc discharge intensity and energy density increased, and the CO2 reduction conversion efficiency and VOCs degradation efficiency increased, with the increase of the electrode spacing and the decrease of the diameter of the conductive microwire.

[0107] The above description of the embodiments is for facilitating the ordinary skilled in the art to understand and use the application. Those skilled in the art can obviously make various modifications to the embodiments and apply the general principles described herein to other embodiments without creative labor. Therefore, the application is not limited to the above embodiments, and the improvements and modifications made by those skilled in the art according to the disclosure of the application without departing from the scope of the application should be within the protection scope of the application.

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 initiation electrode (3) inside the housing (4); characterized in that, the upper electrode (1) and the lower electrode (2) are both electrodes with micron filament brushes, comprising a conductive base plate (7) and a conductive micron filament bundle (8) inlaid on the conductive base plate (7); the initiation electrode (3) is a movable electrode with multiple needle tips, comprising a conductive support (10) and needle-shaped electrodes inlaid thereon, the needle-shaped electrodes are fixed on the conductive support (10) at one end and suspended above the lower electrode (2) at the other end; the conductive support (10) moves up and down, driving the needle-shaped electrodes to move between the upper electrode (1) and the lower electrode (2).

2. A high density discharge plasma device for large spaces according to claim 1, characterized in that, The lower limit of the movement of the initiation 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 needle tip of the needle-shaped electrode is 3-5 mm away from the micron filament brush on the lower electrode (2); The upper stop point is the position where the needle tip of the needle-shaped electrode is immersed in the micron filament brush of the upper electrode (1).

3. A high density discharge plasma device for large spaces according to claim 1, characterized in that, The tessellation density of the conductive micronic filaments (8) is 4 bundles / cm 2 - 16 bundles / cm 2 Each conductive micronic filament (8) comprises 5-50 conductive micronic filaments, each having a diameter of 2-20 μm and a length of 5-30 mm.

4. A high density discharge plasma device for large spaces according to claim 1, characterized in that, The conductive base plate (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 both of an alloy fiber and a silicon carbide fiber.

5. A high density discharge plasma device for large spaces according to claim 1, characterized in that, The needle tip diameter of the needle electrode of the initiating electrode (3) is 10 μm to 50 μm, and the number of the needle electrodes per 1 cm 2 corresponding to the needle tip of at least one needle electrode on the conductive substrate (7).

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

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

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

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

10. Use of a high-density discharge plasma device according to any one of claims 1 to 9, characterized in that: The device comprises the following steps: a. When starting operation, first push the needle tip of the initiation electrode (3) to the lower stop point, turn on the power supply (9) and gradually increase the voltage, so that filament discharge occurs between them; b. When the above discharge reaches a stable state, pull the initiation electrode (3) up, gradually increase the distance between the needle tip and the micron filament brush of the lower electrode (2), and simultaneously increase the voltage of the power supply (9), so that the discharge space gradually extends upward; c. When the initiation electrode (3) is pulled to the upper stop point and the needle tip is immersed in the micron filament brush of the upper electrode (1), the discharge extends to the entire region between the upper and lower electrodes at this time, and the plasma energy density is adjusted by adjusting the voltage of the power supply (9).

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