Dielectric barrier discharge plasma reactor and method of use thereof

Abstract

The application provides a dielectric barrier discharge plasma reaction device and an application method, which comprise an electrode, a sealing cover, an aeration assembly and a reaction chamber, the electrode is fixed in the reaction chamber through the sealing cover, the sealing cover is provided with an air inlet hole, and the reaction chamber is provided with an air outlet; the electrode comprises a high-voltage rod, a dielectric layer and a low-voltage part from inside to outside in sequence, the high-voltage rod is wrapped by the dielectric layer, and the low-voltage part is wound or covered outside the dielectric layer; the aeration assembly comprises a hollow circular table and an aeration head, the hollow circular table is connected with the sealing cover, and the aeration head is connected with the hollow circular table. By arranging the dielectric layer between the high-voltage rod and the low-voltage part, the dielectric layer is used to effectively limit the discharge current by the capacitive coupling effect of the dielectric layer barrier discharge, so that the discharge current is maintained in a stable state, the transition of the discharge mode to high-temperature arc is effectively avoided, the operation energy consumption is significantly reduced, and the operation safety is improved.

Description

Technical Field

[0001] This invention relates to the field of plasma activation technology, specifically to a dielectric barrier discharge plasma reaction device and its application method. Background Technology

[0002] Low-temperature plasma, rich in reactive oxygen species, reactive nitrogen species, free electrons, and other active particles, exhibits significant physical, chemical, and biological effects in fields such as food preservation, medical disinfection and treatment, and material modification, making it a current hot topic in interdisciplinary research. Currently, experiments and applications utilizing low-temperature plasma are mainly divided into two modes: direct and indirect treatment. Direct treatment involves directly applying a plasma jet or discharge region to the surface of the object being treated. Indirect treatment involves first applying plasma to a liquid medium such as water or saline solution to prepare a plasma-activated solution rich in long-lived active substances, which is then applied to the target object. Indirect treatment methods are increasingly favored by researchers and practitioners outside of physics due to their advantages such as operational flexibility, long-lasting effects, and ease of storage and transportation.

[0003] Chinese invention patent document CN120864628A discloses a plasma-activated water preparation device. The plasma generation module includes a tube, a high-voltage electrode, an insulating dielectric layer, and a low-voltage electrode. The tube has an air inlet and multiple micropores. At least part of the high-voltage electrode is disposed within the tube, forming a gap between the high-voltage electrode and the inner surface of the tube. The micropores and the air inlet are connected to the gap. The outer surface of the high-voltage electrode is covered with an insulating dielectric layer. The low-voltage electrode is disposed on the outer surface of the tube and is used to contact the target activation solution. The high-voltage electrode is sealed with insulating material and maintains a distance from the low-voltage electrode, with the target activation solution filling the space between the electrodes. During use, the target solution may enter the gap, posing a risk of circuit breakage. A large working gas flow is required to prevent the target solution from entering the gap; however, an excessively large working gas flow can also pose a safety hazard. Summary of the Invention

[0004] The technical problem to be solved by this invention is to improve the safety of a dielectric barrier discharge plasma reaction device used in the laboratory and to reduce energy consumption.

[0005] The present invention solves the above-mentioned technical problems through the following technical means: The first aspect of the present invention provides a dielectric barrier discharge plasma reaction device, comprising an electrode, a sealing cover, an aeration assembly, and a reaction chamber. The electrode is fixed in the reaction chamber by the sealing cover, which has an air inlet, and the reaction chamber has an air outlet. The electrode comprises, from the inside out, a high-pressure rod, a dielectric layer, and a low-pressure section. The high-pressure rod is wrapped by the dielectric layer, and the low-pressure section is wrapped around or covered by the dielectric layer. The aeration assembly comprises a hollow frustum and an aeration head. The hollow frustum is connected to the sealing cover, and the aeration head is connected to the hollow frustum.

[0006] Beneficial effects: This invention, by setting a dielectric layer between the high-voltage rod and the low-voltage section, effectively limits the discharge current by utilizing the capacitive coupling effect of the dielectric layer to block the discharge, thus maintaining the discharge current in a stable state. This effectively avoids the transition of the discharge mode to a high-temperature arc, significantly reducing operating energy consumption and improving operational safety. Furthermore, by setting a hollow frustum, this invention accelerates the mass transfer and reaction rate between the plasma and the reaction solution, significantly improving the gas-liquid contact effect and increasing the efficiency of activation solution preparation.

[0007] Preferably, the high-pressure rod is made of a high-temperature resistant metal material.

[0008] More preferably, the high-pressure rod is a stainless steel rod or a copper rod.

[0009] Preferably, the low-pressure section is a metal wire or a metal sheet.

[0010] Preferably, when the low-voltage section is a metal wire, the metal wire is wound around the outside of the dielectric layer; when the low-voltage section is a metal sheet, the metal sheet covers the outside of the dielectric layer.

[0011] Preferably, the dielectric layer is an insulating material.

[0012] More preferably, the insulating material is one of quartz, polytetrafluoroethylene, alumina, and zirconium oxide.

[0013] Preferably, the thickness of the dielectric layer is 2~5mm.

[0014] Beneficial effects: By setting the thickness of the dielectric layer to 2~5mm, the input voltage can be maintained at 0~30kV and the frequency at 0~10kHz. Within this voltage and frequency range, the electrode discharge is stable, the generated plasma is more uniform, and the operation is safer. It avoids the risk of direct discharge breakdown when the dielectric layer is too thin, and at the same time prevents electrode corrosion and extends service life. If the dielectric layer is too thick, a higher input voltage is required, which increases the safety hazard or makes it impossible to break down the working gas to generate plasma.

[0015] Preferably, the sealing cover includes an upper cover and a sealing end cover, the upper cover being connected to the sealing end cover, the upper cover covering the top of the reaction chamber, the electrode being fixed in the reaction chamber by the sealing end cover, and the sealing end cover having an air inlet; the hollow frustum is connected to the sealing end cover.

[0016] Preferably, the ratio of the inner diameter of the upper end to the inner diameter of the lower end of the hollow frustum is 2 to 4:1.

[0017] Beneficial effects: This invention generates plasma by connecting electrodes to a power source. As the plasma passes through the hollow frustum, its flow velocity increases due to the different diameters at its upper and lower ends, thereby improving the mass transfer rate and reaction efficiency between the plasma and the reaction solution.

[0018] Preferably, the sealing end cap is provided with a fixing hole, the inner diameter of which is 10~20mm.

[0019] Beneficial effects: By setting the inner diameter of the fixing hole to 10~20mm, the fixing hole can be adapted to electrodes of different sizes. It can meet the needs of increasing or decreasing parameters such as output voltage and frequency under different working gas atmospheres, and more stably excite the working gas to generate plasma composed of specific active particles, thereby obtaining the corresponding activation solution.

[0020] Preferably, the diameter of the air inlet is 2 to 5 mm.

[0021] Beneficial effects: This invention allows different working gases to be introduced through an air inlet. The flow rate of the working gas affects plasma generation. If the air inlet is too small, gas disturbance will significantly affect the stability of plasma generation. If the air inlet is too large, it will be impossible to maintain the purity and continuous supply of the working gas.

[0022] Preferably, the aeration head is connected to the hollow frustum by a thread.

[0023] Beneficial effects: This invention connects the aeration head to the hollow truncated cone via a thread, making it convenient to replace aeration heads of different sizes according to the concentration of activated particles.

[0024] The second aspect of the present invention provides a method for applying the above-mentioned dielectric barrier discharge plasma reaction device, comprising the following steps: injecting a reaction solution into the reaction chamber, fixing a sealing cover at the top opening of the reaction chamber, fixing an electrode in a hollow truncated cone, placing an aeration assembly connected to the sealing cover in the reaction chamber, wherein the aeration head is completely submerged in the reaction solution, then connecting the high-voltage rod and the low-voltage part to a power source, and the working gas entering the reaction chamber through the air inlet of the sealing cover to generate plasma in the hollow truncated cone. The plasma is carried by the airflow and blown into the aeration head through the acceleration effect of the hollow truncated cone. The aeration head generates tiny bubbles in the reaction solution to obtain an activated solution, and the working gas flows out through the air outlet.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention provides a dielectric barrier discharge plasma activation solution preparation device and application method, which can flexibly select working gas and adjust breakdown voltage and frequency parameters according to the requirements of the target activation solution for the type and concentration of active particles. At the same time, it can replace electrodes to achieve precise adaptation to multiple working conditions.

[0026] Compared with the prior art, the present invention tightly couples the high and low voltage end electrodes through an insulating dielectric layer and fixes them through fixing holes, ensuring the stability of the discharge channel and the uniformity of plasma, while avoiding the risk of electrochemical corrosion and pollution caused by direct contact between the electrodes and the solution, thus improving safety and reliability.

[0027] This invention features a hollow frustum that allows for adjustment of the plasma gas flow rate, improving mass transfer efficiency. This also enables flexible adjustment of the dimensions of the electrodes and the connected aeration head. By controlling the ratio of the inner diameter of the upper and lower ends of the hollow frustum, the mass transfer efficiency between the plasma and the solution is enhanced, increasing the concentration of active particles generated per unit time and improving gas-liquid contact efficiency. The aeration device, connected to a sealed end cap, is tightly integrated with the plasma generation area. The airflow carries the plasma through the hollow frustum, accelerating its mixing with the reaction solution and preventing the escape of working gas that could cause liquid surface fluctuations and loss of active ingredients.

[0028] This invention can ensure the stability and safety of the prepared activation solution while maintaining the consistency of the physicochemical properties of the product under the same parameters, thus significantly improving the preparation efficiency. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the electrode structure in Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the sealing cap and aeration assembly in Embodiment 1 of the present invention; Figure 3 This is a top view of the sealing end cap in Embodiment 1 of the present invention; Figure 4 This is a three-dimensional structural diagram of the aeration component in Embodiment 1 of the present invention; Figure 5 This is a side view of the reaction chamber in Embodiment 1 of the present invention; Figure 6 This is a physical diagram of the dielectric barrier discharge plasma reaction device used in Embodiment 2 of the present invention. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. It should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0032] Example 1 according to Figure 1-5 As shown, this embodiment provides a dielectric barrier discharge plasma reaction device, which includes an electrode 10, a sealing cover 20, an aeration assembly 30, and a reaction chamber 40. The electrode 10 is fixed in the reaction chamber 40 by the sealing cover 20, and the aeration assembly 30 is fixed to the bottom of the sealing cover 20 and placed inside the reaction chamber 40 by the sealing cover 20.

[0033] The electrode 10 includes a high-voltage rod 11, a dielectric layer 12, and a low-voltage section 13. The low-voltage section 13 is made of copper wire. The high-voltage rod 11 is a stainless steel rod with a diameter of 10 mm and a length of 200 mm. The outer wall of the high-voltage rod 11 is wrapped by the dielectric layer 12. There is no gap between the outer wall of the high-voltage rod 11 and the inner wall of the dielectric layer 12. The dielectric layer 12 is a polytetrafluoroethylene hollow tube with an inner diameter of 10 mm, an outer diameter of 13 mm, a length of 150 mm, and a thickness of approximately 3 mm. The top of the high-voltage rod 11 protrudes by approximately 50 mm for connection to a power source. The low-voltage section 13 is wound equidistantly around the outer wall of the dielectric layer 12. The copper wire has a diameter of 3 mm.

[0034] The sealing cover 20 includes an upper cover 21 and a sealing end cover 22. The upper cover 21 has a through hole (not shown in the figure) at its center that connects to the sealing end cover 22. The inner diameter of the through hole matches the outer diameter of the sealing end cover 22, which is sufficient to connect the upper cover 21 and the sealing end cover 22 to achieve a sealing effect. The sealing end cover 22 has an air inlet 221. In this embodiment, working gas is introduced through the air inlet 221. The working gas is not limited in any way and can be air, nitrogen, argon, chlorine, etc. The inner diameter of the air inlet 221 is 4mm. At the same time, the sealing end cover 22 has a fixing hole 222 at its center. The fixing hole 222 is used to fix the electrode 10. Specifically, the electrode 10 is fixed in the fixing hole 222 with hot melt adhesive, which also seals the fixing hole 222 to ensure stable airflow in the air inlet 221. One end of the copper wire of the low-pressure part 13 needs to be passed through the fixing hole for connection to the power supply. The inner diameter of the fixing hole 222 is 16mm. The upper end cap 21 has a height of 20mm and a diameter of 90mm; the sealing end cap 22 has a height of 50mm and a diameter of 40mm. Both the upper end cap 21 and the sealing end cap 22 are made of quartz.

[0035] The aeration assembly 30 includes a hollow frustum 31 and an aeration head 32. The hollow frustum 31 is connected to a sealing end cap 21, with the upper end being the connection point between the hollow frustum 31 and the sealing end cap 21. The electrode 10 is placed inside the hollow frustum 31. The inner diameter of the upper end of the hollow frustum 31 is 40 mm, and the inner diameter of its lower end is 20 mm. The height of the hollow frustum 32 is 60 mm. The aeration head 32 is connected to the lower end of the hollow frustum 31 by a thread. The lower end of the hollow frustum 31 has an internal thread, and the aeration head 32 has an external thread. The internal and external threads match, and the connection or disconnection of the hollow frustum 31 and the aeration head 32 can be achieved by rotation. A suitable aeration head 32 can be replaced according to the required concentration of active particles in the activation solution. For example, a suitable aeration head 32 can be replaced according to its surface area. The larger the surface area of ​​the aeration head 32, the higher the concentration of active particles in the prepared activation solution; the smaller the surface area of ​​the aeration head 32, the lower the concentration of active particles in the prepared activation solution.

[0036] The reaction chamber 40 is made of quartz and is an open cylindrical container used to hold the reaction solution. The reaction solution is not limited in any way; it can be pure water, physiological saline, buffer solution, cell culture medium, a complex solution containing organic components, or liquids with different viscosities, conductivity, and surface tensions. The reaction chamber 40 has a vent 41 near the top for discharging the working gas. The reaction chamber 40 has a height of 200 mm and an inner diameter of 90 mm.

[0037] In this embodiment, the upper end cover 21, sealing end cover 22, hollow frustum 31, aeration head 32, and reaction chamber 40 in the dielectric barrier discharge plasma reaction device can be assembled during use and disassembled when not in use; at the same time, the electrode 10, hollow frustum 31, and aeration head 32 and other components can be replaced according to the activation solution.

[0038] Example 2 according to Figure 6 As shown, this embodiment provides an application method for a dielectric barrier discharge plasma reaction device, specifically including the following steps: S1. If the dielectric barrier discharge plasma reactor is not assembled, it can be assembled. Specifically, the sealing end cap 22 is fixedly connected to the upper end cap 21, the electrode 10 is fixed in the fixing hole 222 of the sealing end cap 22 with hot melt adhesive, and then the hollow frustum 31 and the aeration head 32 are connected by threads. The upper end of the hollow frustum 31 is connected to the bottom of the sealing end cap 22. One end of the electrode 10 is exposed in the air for connecting to the power supply, and the other end is placed inside the hollow frustum 32.

[0039] S2. Inject the reaction solution into the reaction chamber 40. In this embodiment, the reaction solution is pure water, and the volume of pure water added is 600ml. Then, fix the upper end cap 21 to the open top of the reaction chamber 40. At this time, the aeration component 30 is placed inside the reaction chamber 40, and the aeration head 32 is just submerged in the reaction solution. The working gas is introduced through the air inlet 221. In this embodiment, air is used. Then, connect the high-voltage rod 11 and the low-voltage part 13 of the electrode 10 to the power supply. After the power is turned on, the electrode 10 emits a bright pink light under the action of the high-voltage electric field. Its luminous area and the wound copper wire With consistent length, the collisions between high-energy electrons and the working gas are accelerated, resulting in an avalanche effect and generating a large number of high-energy particles. This generates plasma within the hollow frustum 31. The plasma, carried by the airflow, passes through the hollow frustum 31. Because the ratio of the inner diameter of the upper end to the inner diameter of the lower end of the hollow frustum 31 is 2:1, the plasma velocity ratio passing through the upper and lower ends of the hollow frustum 31 per unit time is 1:4, thus increasing the plasma velocity by four times. Accelerated by the hollow frustum 31, the plasma rapidly passes through the aerator head 32 and enters the reaction solution, generating a large number of microbubbles. The surface area of ​​the aerator head 32 is 28.3 cm². 2 This allows the plasma to fully contact and react with the reaction solution, ultimately resulting in an activated solution, while the working gas flows out through the outlet 41.

[0040] Example 3 This embodiment provides a dielectric barrier discharge plasma reaction device. Compared with Embodiment 1, the difference is that the ratio of the inner diameter of the upper end to the inner diameter of the lower end of the hollow truncated cone is replaced by 3:1 instead of 2:1. Therefore, the ratio of the plasma velocity passing through the upper and lower ends of the hollow truncated cone per unit time is 1:9, thus increasing the plasma velocity by 9 times.

[0041] Example 4 This embodiment provides a dielectric barrier discharge plasma reaction device. Compared with embodiment 1, the difference is that the ratio of the inner diameter of the upper end to the inner diameter of the lower end of the hollow truncated cone is replaced by 4:1 instead of 2:1. Therefore, the ratio of the plasma velocity passing through the upper and lower ends of the hollow truncated cone per unit time is 1:16, thus increasing the plasma velocity by 16 times.

[0042] In summary, when the ratio of the inner diameter of the upper end to the lower end of the hollow frustum 31 is greater than 1, the hollow frustum is beneficial for increasing the plasma flow rate, thereby improving the plasma mass transfer efficiency. In practical applications, a suitable ratio of the inner diameter of the upper end to the lower end of the hollow frustum 31 can be designed based on the volume of the reaction solution and the concentration of the prepared active particles.

[0043] Comparative Example 1 This comparative example provides a dielectric barrier discharge plasma reaction device. The difference between this comparative example and Example 1 is that the hollow frustum 31 is omitted, and the aeration head 32 is directly connected to the sealing end cap 22.

[0044] Since the hollow frustum 31 was not used in this comparative example, the inner diameter of the fixing hole 222 must be consistent with the inner diameter of the aeration head 32. On the one hand, the size of the electrode 10 cannot be adjusted according to the characteristics of the actual reaction solution, and the required input voltage and frequency will be greatly increased, increasing the experimental safety risks. On the other hand, it would cause one end of the electrode 10 in Example 1 to be placed inside the aeration head 32, making it very easy for the reaction solution to splash onto the electrode 10, causing safety risks such as short circuits. Alternatively, shortening the length of the electrode 10 would reduce the amount of plasma generated and the concentration of the activation solution, resulting in a longer reaction time and a lower efficiency in preparing the activation solution.

[0045] Comparative Example 2 This comparative example provides a dielectric barrier discharge plasma reaction device. The difference between this comparative example and Example 1 is that the hollow frustum 31 is replaced with a hollow tube with the same inner diameter at both ends.

[0046] In this comparative example, the dielectric barrier discharge plasma reactor generates plasma in the hollow tube. The plasma passes through the hollow tube through the working gas. Due to the length of the hollow tube, the passage time is increased, which greatly increases the interaction time between the plasma and the reaction solution, resulting in a lower efficiency in preparing the activation solution.

[0047] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A dielectric barrier discharge plasma reaction device, characterized in that, The device includes electrodes, a sealing cap, an aeration assembly, and a reaction chamber. The electrodes are fixed in the reaction chamber by the sealing cap, which has an air inlet. The reaction chamber has an air outlet. The electrodes consist of a high-pressure rod, a medium layer, and a low-pressure section from the inside out. The high-pressure rod is wrapped by the medium layer, and the low-pressure section is wrapped around or covered by the medium layer. The aeration assembly includes a hollow frustum and an aeration head. The hollow frustum is connected to the sealing cap, and the aeration head is connected to the hollow frustum.

2. The dielectric barrier discharge plasma reaction device according to claim 1, characterized in that, The high-pressure rod is made of high-temperature resistant metal; the low-pressure section is made of metal wire or metal sheet.

3. The dielectric barrier discharge plasma reaction device according to claim 2, characterized in that, When the low-voltage section is a metal wire, the metal wire is wound around the outside of the dielectric layer; when the low-voltage section is a metal sheet, the metal sheet covers the outside of the dielectric layer.

4. The dielectric barrier discharge plasma reaction device according to claim 1, characterized in that, The dielectric layer is an insulating material.

5. The dielectric barrier discharge plasma reaction device according to claim 1, characterized in that, The thickness of the dielectric layer is 2~5mm.

6. The dielectric barrier discharge plasma reaction apparatus according to claim 1, characterized in that, The sealing cover includes an upper cover and a sealing end cover. The upper cover is connected to the sealing end cover and covers the top of the reaction chamber. The electrode is fixed in the reaction chamber through the sealing end cover. The sealing end cover is provided with an air inlet. The hollow frustum is connected to the sealing end cover.

7. The dielectric barrier discharge plasma reaction device according to claim 1, characterized in that, The ratio of the inner diameter of the upper end to the inner diameter of the lower end of the hollow frustum is 2 to 4:

1.

8. The dielectric barrier discharge plasma reaction apparatus according to claim 1, characterized in that, The sealing end cap is provided with a fixing hole with an inner diameter of 10~20mm.

9. The dielectric barrier discharge plasma reaction apparatus according to claim 1, characterized in that, The aeration head is connected to the hollow truncated cone by a thread.

10. A method of applying the dielectric barrier discharge plasma reaction device as described in any one of claims 1-9, characterized in that, Includes the following steps: The reaction solution is injected into the reaction chamber, the sealing cap is fixed at the top opening of the reaction chamber, and the electrode is fixed in the hollow truncated cone. The aeration assembly is connected to the sealing cap and placed in the reaction chamber, with the aeration head completely submerged in the reaction solution. Then, the high-pressure rod and the low-pressure part are connected to the power supply. The working gas enters the reaction chamber through the air inlet of the sealing cap and generates plasma in the hollow truncated cone. The plasma is carried by the airflow through the hollow truncated cone and blown into the aeration head. The aeration head generates tiny bubbles in the reaction solution to obtain the activated solution. The working gas flows out through the air outlet.

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