DBD synergistic photocatalysis air purification device and method

Abstract

The invention provides a DBD synergetic photocatalysis air purification device and method.A DBD reactor set is arranged in a shell, the upper portion of the DBD reactor set is fixed through a fixed sealing fixing cover plate, each reactor fixing plug corresponds to a three-electrode DBD reactor, an inner air inlet is formed in each reactor fixing plug, the DBD reactor set is fixed through a honeycomb-shaped fixing plate, and the honeycomb-shaped fixing plate is provided with an outer air inlet; a honeycomb-shaped fixing plate is arranged in the middle of the three-electrode DBD reactor, a partition plate is arranged below the honeycomb-shaped fixing plate, a power module is arranged below the partition plate, each three-electrode DBD reactor comprises two coaxial quartz tubes, a high-voltage electrode is clamped between the two quartz tubes, and photocatalyst-loaded porous metal electrodes are arranged on the outer wall of the outer quartz tube and the inner wall of the inner quartz tube. According to the invention, two-stage reaction is adopted, so that the contact area between the pollution gas and the reactor and the catalyst is increased, and the retention time of the pollution gas in the reactor is also increased, so that the air purification is more thorough. The high-voltage electrode is clamped in the quartz medium, so that carbon deposition and loss are avoided.

Description

Technical Field

[0001] The present invention belongs to the field of air purification and relates to a DBD collaborative photocatalytic air purification device and method. Background Art

[0002] The low-temperature plasma technology is a new type of molecular activation technology, showing great development potential in the fields of air pollution control and waste gas treatment. As a new type of air purification technology, its efficient gas activation and purification capabilities have attracted much attention. During the low-temperature plasma discharge process, the electron temperature can reach a very high level, but the temperature of heavy particles is very low, even close to room temperature. Therefore, the low-temperature plasma has advantages such as good chemical activity and high energy utilization efficiency. Introducing low-temperature plasma into the field of air purification, the air is activated by high voltage and reactive oxygen molecules are released, which can actively capture and decompose volatile organic compounds and odor molecules in the air, and at the same time can inactivate substances such as bacteria existing in the air, achieving the effect of purifying the air in all aspects. The photocatalytic technology is a technology that uses light energy to activate the catalyst to decompose harmful substances in the air to achieve the purpose of purifying the air.

[0003] At present, a variety of plasma treatment devices have achieved remarkable results in the application of air purification, but there is still some room for improvement in terms of treatment efficiency, energy consumption, and device structure. Currently, the air purification treatment devices based on plasma technology mostly use dielectric barrier discharge plasma (DBD). Its advantages are that it can be applied in a wide range of air pressures, a wide range of discharge frequencies, simple structure, and good discharge uniformity; however, DBD requires a high power output of the power supply, and some energy cannot be used for discharge, resulting in unnecessary waste of energy. The photocatalytic technology can completely decompose organic pollutants into carbon dioxide and water, with high removal efficiency; no additional chemical substances need to be added during the photocatalytic process, avoiding secondary pollution. Using DBD collaborative photocatalytic technology to purify air can not only improve the treatment efficiency of polluted gases and energy utilization efficiency, but also activate the photocatalyst by the ultraviolet rays generated by plasma discharge.

[0004] For the current dielectric barrier discharge plasma gas treatment device, there are some defects: 1. Using DBD combined with photocatalysis can more effectively treat polluted gases. However, for reactors of this type, an additional ultraviolet light source is required to activate the photocatalyst. This not only increases the ultraviolet light source but also greatly improves the energy consumption, which is not conducive to practical applications. In addition, the catalyst is filled and placed in the reactor, and it cannot be completely activated by ultraviolet light and has a certain impact on the gas flow. 2. There is a lack of an air purification device system for the dielectric barrier discharge low-temperature plasma technology. The existing devices only have the reactor main body part and lack the supporting systems related to the development of this technology, so the maximum advantage of this technology cannot be exerted and it is far from practical applications. 3. Currently, conventional DBD reactors have problems such as short residence time of gas in the reactor and insufficient interaction between reactants and plasma, resulting in the air containing pollutants being blown out before reacting with the active particles generated in the reactor. 4. Most of the existing reactors are for research use and are designed for experimental purposes. In actual applications, when facing gases with large flow rates, complex pollutant components, and relatively low overall concentrations, problems such as low gas degradation rate, low reaction rate, and poor stability often occur. 5. Some of the existing DBD reactors only degrade single gases and cannot cope with the challenges of complex gas types in the real home environment. The application fields are narrow and large-scale promotion cannot be carried out.

[0005] In Patent CN213610668U, the plasma combined with photocatalysis technology is adopted. Although the treatment effect is good, safe and stable, it requires an additional ultraviolet light source and tail gas adsorbent, which undoubtedly increases the energy consumption and complexity of the entire device. In addition, the device stacks the photocatalyst in the reactor, so some of the catalysts cannot be irradiated by ultraviolet light and there is a problem of incomplete activation.

[0006] The device shown in Patent CN209815681U combines dielectric barrier discharge plasma with sterilization and disinfection to form a complete system. It adopts a flat-type DBD. Although the problem of batch treatment is solved, the treatment effect is sacrificed. During the treatment process of the flat-type DBD, the residence time of pollutants in the reaction area is short and they cannot fully react with the active substances generated by the discharge plasma. The gas to be treated is often discharged by the fan before fully reacting with the plasma, so the treatment efficiency is low.

[0007] Patent CN118950025A adopts a catalytic material loaded on a porous carrier for adsorption first and then catalytic degradation. However, its adsorption catalytic material uses precious metals, which are expensive and not suitable for large-scale promotion and use. Summary of the Invention

[0008] 1. Technical problems to be solved: The existing plasma air purification technology, including the cooperative photocatalyst treatment technology, has practical application problems such as incomplete activation of the photocatalyst and unsuitability of traditional reactors for large air intake.

[0009] 2. Technical solution: To solve the above problems, the present invention provides a DBD cooperative photocatalytic air purification device, including a housing. A DBD reactor group is provided inside the housing. An air outlet is provided on the side of the housing. In each DBD reactor group, multiple three-electrode DBD reactors are vertically arranged. The DBD reactor group is fixed above by a fixed sealing fixed cover plate. Above the sealing fixed cover plate, there are reactor fixing plugs equal in number to the three-electrode DBD reactors. For one three-electrode DBD reactor, each reactor fixing plug is provided with an inner air inlet. The DBD reactor group is fixed by a honeycomb-shaped fixing plate. A partition is provided below the honeycomb-shaped fixing plate. A power supply module is provided below the partition. Each three-electrode DBD reactor includes two coaxial quartz tubes. The high-voltage electrode is a metal cylinder sandwiched between the two quartz tubes. Loaded photocatalyst porous metal electrodes are provided on the outer wall of the outer quartz tube and the inner wall of the inner quartz tube.

[0010] An air intake fan is provided at the external air inlet above inside the housing.

[0011] The power supply module is an AC power supply, and the AC power supply is adjusted to a suitable voltage by a power adapter 10 to supply power to the device.

[0012] The photocatalyst is a TiO2 photocatalyst.

[0013] There are five three-electrode DBD reactors.

[0014] The honeycomb-shaped fixing plate is provided with five holes, and each hole corresponds to a three-electrode DBD reactor.

[0015] The present invention also provides a DBD cooperative photocatalytic air purification method, using the DBD cooperative photocatalytic air purification device described above.

[0016] 3. Beneficial effects: The present invention is used for air purification in a home environment and can effectively remove polluting gases such as formaldehyde and toilet odors in the air that cause physical discomfort. It utilizes five three-electrode dielectric barrier discharge (DBD) reactors as the core of the device. Among them, the ground electrodes of the reactors are two porous metal electrodes loaded with photocatalysts. When operating, surface discharges are formed on the surfaces and ultraviolet rays are generated, thereby activating the photocatalysts loaded on the ground electrodes. This device adopts a two-stage structure. In the first-stage reaction, the polluting gases enter the inner cavity formed by the inner glass tube of the reactor and the ground electrode evenly through an intake fan, and are discharged from the tail end of the reactor after being synergistically treated. The second-stage reaction takes place on the ground electrodes on the outer glass tube of the reactor. The three-electrode segmented treatment greatly increases the contact area between the polluting gases and the reactor and the catalyst, and also increases the residence time of the polluting gases in the reactor, making the air purification more thorough and achieving the purpose of purifying the air. In addition, this device also sandwiches the high-voltage electrode between two layers of quartz dielectrics, so that the polluting gases do not come into contact with the high-voltage electrode, effectively avoiding the corrosion of the high-voltage electrode by the gases and prolonging the service life of the reactor. Description of the Drawings

[0017] Figure 1 It is a schematic diagram of a DBD-synergistic photocatalytic air purification device.

[0018] Figure 2 It is a cross-sectional view of a DBD-synergistic photocatalytic air purification device.

[0019] Figure 3 It is a top view of the air purification device.

[0020] Figure 4 It is an inner top view of the air purification device.

[0021] Figure 5 It is a schematic diagram of the intake fan.

[0022] Figure 6 It is a schematic diagram of a DBD-synergistic photocatalytic reactor group.

[0023] Figure 7 It is an assembly drawing of the DBD reactor group.

[0024] Figure 8 It is a schematic diagram of the sealed fixed cover plate.

[0025] Figure 9 It is a schematic diagram of the honeycomb-shaped fixing plate.

[0026] Figure 10 It is a schematic diagram of a three-electrode coaxial DBD reactor.

[0027] Figure 11 It is a cross-sectional view of a three-electrode coaxial DBD reactor.

[0028] Figure 12It is an assembly drawing of a three - electrode coaxial DBD reactor.

[0029] Figure 13 It is a porous ground electrode loaded with photocatalyst.

[0030] Figure 14 It is a device operation flow chart.

[0031] Explanation of reference numerals in the drawings: 1. Outer air inlet; 2. Air outlet; 3. Device housing; 4. Intake fan; 5. Fixed plug; 501. Inner air inlet; 6. Sealed fixed cover plate; 7. Three - electrode coaxial DBD reactor; 701. Porous ground electrode loaded with photocatalyst; 702. Quartz tube; 703. High - voltage electrode; 8. Honeycomb fixed plate; 9. Partition board; 10. Power adapter. Detailed implementation mode

[0032] The present invention will be described in detail below with reference to the drawings and embodiments.

[0033] As Figure 1 shown, a DBD - assisted photocatalytic air purification device includes a housing 3. Inside the housing 3, there is a DBD reactor group. On the side of the housing 3, there is an air outlet 2. In each DBD reactor group, multiple three - electrode DBD reactors 7 are placed vertically.

[0034] As Figures 3 - 7 shown, the upper part of the DBD reactor group is fixed by a fixed - sealed cover plate 6. Above the sealed fixed cover plate 6, there are reactor fixed plugs 5 equal in number to the three - electrode DBD reactors 7. Each reactor fixed plug 5 passes through the sealed fixed cover plate 6 and corresponds to a three - electrode DBD reactor 7. Inside each reactor fixed plug 5, there is an inner air inlet 501. The sealed fixed cover plate 6 separates the intake area from the reaction area. On the sealed fixed cover plate 6, there are N reactor fixed plugs 5 and inner air inlets 501.

[0035] In one embodiment, the diameter of the inner air inlet 501 is 30 - 35 mm. Polluted gas is sent into the purification device and is sent into the DBD reactor through the inner air inlet 501 for degradation.

[0036] The DBD reactor group is fixed by a honeycomb fixed plate 8. The honeycomb fixed plate 8 keeps the reactor assembly stable without affecting gas flow.

[0037] Below the honeycomb fixed plate 8, there is a partition board 9. Below the partition board 9, there is a power module. The partition board 9 separates the polluted gas reaction chamber from the power supply chamber, avoiding the corrosion of the power adapter by polluted gas. In one embodiment, as Figure 5 、 Figure 6 、 Figure 9As shown in FIG. 12, each of the three - electrode DBD reactors 7 includes two coaxial quartz tubes 702. The high - voltage electrode 703 is a metal cylinder sandwiched between the two quartz tubes 702. The outer wall of the outer quartz tube 702 and the inner wall of the inner quartz tube 702 are both provided with porous metal electrodes 701 loaded with photocatalyst.

[0038] The pores of the porous electrode are loaded with photocatalyst. The ultraviolet rays generated by dielectric barrier discharge directly activate the photocatalyst without the need to install an additional ultraviolet light source. The photocatalyst is loaded on the pores, which will not cause catalyst stacking and can uniformly activate the photocatalyst.

[0039] Three cylindrical electrodes are nested together to form a three - electrode coaxial DBD, which can form a uniform surface - discharge along the electrode surface. The generated plasma accumulates on the surface of the ground electrode, making the discharge more concentrated and having a better effect. In addition, the high - voltage electrode is sandwiched between two layers of quartz media to avoid contact with polluted gas, protecting the high - voltage electrode.

[0040] This device adopts the form of dielectric barrier discharge with surface - discharge. The generated plasma accumulates on the surface of the ground electrode, making the discharge more concentrated and having a better effect. The ultraviolet rays generated by plasma discharge are relatively weak and have poor penetration performance for quartz media. The form of surface - discharge avoids the problem of needing to penetrate quartz media, enabling it to better activate the titanium dioxide photocatalyst.

[0041] In one embodiment, the photocatalyst is a TiO2 photocatalyst.

[0042] In one embodiment, as Figure 2 and Figure 4 shown, an intake fan 4 is provided at the upper external air inlet 1 inside the housing 3. Polluted gas is sucked into the purification device by the intake fan 4.

[0043] In one embodiment, there are five three - electrode DBD reactors 7.

[0044] In one embodiment, the sealing and fixing cover plate 6 is 140 - 150 mm in length, 140 - 150 mm in width, and 2 - 3 mm in thickness. The surface of the sealing and fixing cover plate 6 has five round holes with a diameter of 30 - 35 mm, and there is also a hexagonal counterbore with an inscribed - circle diameter of 32 - 36 mm outside each round hole. The depth of the counterbore is 1 - 2 mm. This structure can effectively clamp the reactor fixing plug 5.

[0045] In one embodiment, as Figure 6 and Figure 8 shown, the honeycomb - shaped fixing plate 8 is provided with five holes, and each hole corresponds to placing a three - electrode DBD reactor 7. The honeycomb - shaped fixing plate 8 is assembled at the tail end of the DBD reactor group, which can effectively fix the DBD reactor and does not hinder the gas discharged from the tail end of the reactor from participating in the second - stage reaction.

[0046] In one embodiment, the power supply used in the present invention is an AC power supply, and the AC power supply adjusts the alternating current to a suitable voltage through a power adapter to supply power to the device.

[0047] The present invention also provides a DBD-assisted photocatalytic air purification method, which uses the DBD-assisted photocatalytic air purification device as Figure 14 shown, and includes the following steps: Step S01: The air with polluted gas uniformly enters the quartz tube 702 inside each three-electrode DBD reactor 7 through the intake fan 4.

[0048] Step S02: The pollutant molecules of formaldehyde, hydrogen sulfide, ammonia, etc. in the air are co-treated by the plasma and photocatalyst through surface discharge on the ground electrode arranged on the inner wall of the quartz tube 702.

[0049] Step S03: The gas treated in Step S02 is discharged from the tail end of each three-electrode DBD reactor 7, and enters the space formed by the honeycomb in the honeycomb-shaped fixing plate 8 and the outer wall of the outer quartz tube 702.

[0050] Step S04: The gas is co-treated by the plasma and photocatalyst through surface discharge on the ground electrode on the outer wall of the outer quartz tube 702, and is discharged from the air outlet 2.

[0051] This device adopts a two-stage reaction. In the first-stage reaction, the air with polluted gas uniformly enters the reactor through the intake fan. The pollutant molecules such as formaldehyde, hydrogen sulfide, and ammonia in the air are co-treated by the plasma and photocatalyst through surface discharge on the inner cavity formed by the inner glass tube 702 and the ground electrode 701 of the reactor. Subsequently, the gas after the first-stage reaction is discharged from the tail end of the reactor and converges in the space formed by the outer shell 3 and the outer wall of the outer quartz tube 702. The converged gas flows through the discharge channel formed by the outer glass tube 702 and the ground electrode 701 of the shown reactor, and the plasma and photocatalyst are co-treated again to carry out the second-stage reaction. Finally, the purified gas is discharged through the air outlet 2 on the outer shell of this device.

[0052] Adopting a two-stage reaction greatly increases the contact area between the polluted gas and the reactor and the catalyst. At the same time, the design of the three electrodes also increases the residence time of the polluted gas in the reactor, making the air purification more thorough. The high-voltage electrode is clamped in the quartz medium to avoid carbon deposition and loss.

Claims

1. A DBD collaborative photocatalytic air purification device, comprising a housing (3), characterized in that: A DBD reactor group is provided inside the housing (3). An air outlet (2) is provided on the side of the housing (3). A plurality of three-electrode DBD reactors (7) in each DBD reactor group are placed vertically. The upper part of the DBD reactor group is fixed by a fixed sealing cover plate (6). Above the sealing fixed cover plate (6), there are reactor fixing plugs (5) equal in number to the three-electrode DBD reactors (7). Each reactor fixing plug (5) passes through the sealing fixed cover plate (6) and corresponds to a three-electrode DBD reactor (7). An internal air inlet (9) is provided in each reactor fixing plug (5). The DBD reactor group is fixed by a honeycomb-shaped fixing plate (8). A partition plate (14) is provided below the honeycomb-shaped fixing plate (8). A power supply module is provided below the partition plate (14). Each three-electrode DBD reactor (7) includes two coaxial quartz tubes (11). The high-voltage electrode (12) is in the shape of a metal cylinder and is clamped between the two quartz tubes (11). Loaded photocatalyst porous metal electrodes (10) are provided on the outer wall of the outer quartz tube (11) and the inner wall of the inner quartz tube (11).

2. The DBD collaborative photocatalytic air purification device according to claim 1, characterized in that: An air inlet fan (4) is provided at the external air inlet (1) above the inside of the housing (3).

3. The DBD collaborative photocatalytic air purification device according to claim 1, characterized in that: The power supply module is an AC power supply. The AC power supply adjusts the alternating current to a suitable voltage through a power adapter (13) to supply power to the device.

4. The DBD collaborative photocatalytic air purification device according to any one of claims 1-3, characterized in that: The photocatalyst is a TiO2 photocatalyst.

5. The DBD collaborative photocatalytic air purification device according to any one of claims 1-3, characterized in that: There are five three-electrode DBD reactors (7).

6. The DBD collaborative photocatalytic air purification device according to claim 5, wherein: The honeycomb-shaped fixing plate (8) is provided with five holes, and each hole corresponds to a three-electrode DBD reactor (7).

7. A DBD collaborative photocatalytic air purification method. The specific steps of using the DBD collaborative photocatalytic air purification device as described in any one of claims 1-6 are as follows: Step S01: The air with polluted gas enters the inner quartz tube (11) of each three-electrode DBD reactor (7) evenly through the air inlet fan (4). Step S02: Pollutant molecules such as formaldehyde, hydrogen sulfide, and ammonia in the air are synergistically treated by the plasma and photocatalyst through surface discharge on the ground electrode provided on the inner wall of the inner quartz tube (11). Step S03: The gas treated in Step S02 is discharged from the tail end of each three-electrode DBD reactor (7) and enters the space formed by the honeycomb in the honeycomb-shaped fixing plate (8) and the outer wall of the outer quartz tube (11) of the housing through the honeycomb. Step S04: The gas is synergistically treated by the plasma and photocatalyst through surface discharge on the ground electrode of the outer wall of the outer quartz tube (11) and is discharged from the air outlet hole (2).

Images