CN201347357Y - High-concentration ozone generating device - Google Patents

Abstract

A high concentration ozone generating device belongs to the technical fields of gas discharge physics, plasma physics, environmental science and the like. The method is characterized in that water cooling is carried out on a grounding electrode and a discharge electrode at the same time, the discharge gap is an ultra-narrow gap, and the distance is 0.04-0.25 mm; the folding electric field intensity of the ionization discharge in the discharge channel in the gap reaches 450-1500 Td, and the average energy of electrons reaches 10-24 eV; and the concentration of active particles generated by oxygen molecule dissociation, ionization and other reactions is regulated and controlled by electric field parameters, so that the ozone re-decomposition is controlled, and the ozone concentration reaches160～420 g/Nm³. The utility model discloses an effect and benefit adopt water to cool off earthing pole, discharge electrode and super narrow discharge gap simultaneously, have realized that ozone produces the device miniaturization to can produce the ozone of high concentration and large production yield by the high efficiency.

Description

A high concentration ozone generator

technical field

The utility model belongs to the technical fields of gas discharge physics, plasma physics, environmental science and the like, and relates to a high-concentration ozone generating device.

Background technique

Generating high-concentration ozone has always been a research hotspot at home and abroad. Japan’s Mitsubishi Electric and Toshiba Mitsubishi Electric have newly developed narrow-gap (0.3-0.25mm) ozone generators with ozone concentrations of 180g/Nm ³ and 350g/Nm ³ respectively. Japan's Fuji Electric has recently developed an ozone generator with water-cooled discharge electrodes and ground electrodes at the same time, with an ozone concentration of 200g/Nm ³ . Theoretical research shows that there is still a large room for improvement in ozone concentration, and further research is needed to solve its related technologies.

The shortcomings of the current ozone generators are that the discharge gap still has narrowing space; most discharge electrodes have not been cooled, and the further increase of ozone concentration is hindered by the thermal decomposition of ozone; the ionization discharge field in the current ozone generator is too long, usually reaching 0.4~ 1m, the generated ozone is decomposed due to the excitation of active particles, thus restricting the further increase of the ozone concentration; because the ionization discharge electric field is too long, it hinders the further miniaturization of the ozone generator.

Contents of the invention

The purpose of the utility model is to provide a high-concentration ozone generating device aiming at the problems of relatively low ozone concentration, large volume and high energy consumption produced by the existing ozone generating device. The discharge electrode and the ground electrode of the device are cooled with deionized water at the same time, which reduces the thermal decomposition of ozone; and uses a thin dielectric layer formed of Al ₂ O ₃ material with high dielectric constant and high resistivity, and uses ultra-narrow discharge The gap method increases the electric field intensity of the ionization discharge, strengthens the oxygen dissociation reaction, increases the amount of ozone produced, and at the same time increases the flow rate of oxygen accordingly, which is beneficial to inhibit the thermal decomposition reaction of ozone, and realizes the miniaturization of the ozone generating device.

The technical solution adopted by the utility model to solve its technology is:

The utility model adopts deionized water to cool the discharge electrode and the ground electrode; the gap distance is 0.04-0.25mm; the dielectric constant (≥10), high insulation resistivity (≥10 ¹⁴ Ω·cm) is made of Al ₂ O ₃ Thickness of 0.47 ~ 1.0mm thin dielectric layer. Due to the adoption of the above method, a strong ionization discharge in which the ionization equivalent electric field intensity in the discharge channel in the discharge gap reaches 450-1500Td and the average electron energy reaches 10-24eV is realized. This will ionize, dissociate and excite more oxygen molecules into high-concentration active particles, and more ozone will be generated in the regulation of electric field parameters. As we all know, the energy of electrons that promote the decomposition of ozone is 2.0-8.0eV, while the average energy of electrons in strong ionization discharge reaches more than 10eV, and the number of electrons with 2.0-8.0eV will be greatly reduced, thus inhibiting the re-decomposition of ozone. The regulation and control of ozone concentration and production efficiency are realized, and the ozone concentration is improved; at the same time, the re-decomposition of ozone is controlled.

On the other hand, the utility model adopts an ultra-narrow gap of 0.04-0.25mm, which increases the flow rate of oxygen passing through the gap by multiples, helps to take away the heat generated by ozone formation, reduces the temperature in the discharge gap, and then controls The thermal decomposition reaction of ozone improves the ozone concentration and production efficiency; at the same time, it facilitates the rapid transport of ozone, reduces the decomposition probability of ozone, and is also conducive to the improvement of ozone concentration and efficiency.

The effects and benefits of the utility model are: under the condition of water cooling of the discharge electrode and the ground electrode at the same time, the corresponding technology of the ultra-narrow discharge gap is adopted to promote the ozone concentration to 160-420g/Nm ³ ; due to the realization of strong ionization discharge generation Ozone will greatly reduce the length of the ionization discharge electric field (that is, the length of the electrode), and also realize the miniaturization of the ozone generating device.

Description of drawings

Figure 1 is a graph showing the relationship between the dissociation area of ozone and oxygen molecules and the energy of electrons.

Figure 2 is a diagram of the energy distribution of electrons in the plasma.

Fig. 3 is a graph showing the relationship between the average electron energy ε and the reduced electric field intensity.

Fig. 4 is a schematic front sectional view of the structure of Embodiment 1 of the utility model.

Fig. 5 is a side sectional view of Embodiment 1 of the present utility model.

Fig. 6 is a side sectional view of the structure of Embodiment 2 of the present utility model.

Fig. 7 is a side sectional view of the structure of Embodiment 3 of the present invention.

1. Oxygen; 2, 7. Cooling water; 3. Ground electrode; 4. Discharge gap; 5. Dielectric layer; 6. Discharge electrode; 8. Ozone and oxygen; 9. High voltage cable; 10. Alternating high voltage power supply; 11. Separator; 12. Insulation layer; 13. Cooler; 14. Ion exchanger; 15, 16. Valve body.

Detailed ways

The specific embodiment of the utility model is described in detail below in conjunction with technical scheme and accompanying drawing.

From the relationship curve between the dissociation cross-sectional area of ozone molecules and oxygen molecules and electron energy in Figure 1, it can be known that the electrons accelerated by the electric field are vertically excited to dissociate oxygen molecules from the ground state of O ₂ (x ³ ∑g ^- ) to O ₂ (A ³ Δu ⁺ ) state, the required vertical excitation energy is 6.1eV, which is a forbidden transition; when excited from the ground state of O ₂ (X ³ ∑g ^- ) to the state of O ₂ (B ³ ∑u ^- ), the vertical excitation energy of oxygen molecules is 8.4 eV; however, the excitation energy for ozone dissociation is 2eV. When the electrons in the discharge gap obtain energy ≥ 8.4eV from the discharge electric field, oxygen molecules can decompose and ionize into oxygen atoms, ions and free radicals, etc., and generate ozone after colliding with oxygen molecules. It can be seen that electrons with energies between 2.0 and 8.4 eV are useless for generating ozone, and this part of energy seems to be used exclusively for decomposing ozone. The plasma reaction formula of oxygen molecular dissociation, ionization and ozone generation is:

O ₂ (x ³ ∑g ^- )+e ^* →O ₂ (A ₃ ∑u ⁺ )+e (1)

→O( ^3P )+O( ^3P )+e

O ₂ (x ³ ∑g ^- )+e ^* →O ₂ (B ³ ∑u ^- )+e (2)

→O( ^1D )+O( ^3P )+e

O ₂ (x ³ ∑g ^- )+e ^* →O ₂ (A ³ πu ⁺ )+e (3)

→O( ³ P)+O ⁺ ( ¹ S ⁰ )+2e

O+O ₂ +M→O ₃ ^* +M→O ₃ +M (4)

From the plasma electron energy distribution curve in Figure 2, it can be seen that the average energy of electrons in the discharge gap of the ozone generating device currently produced in the market is 5.0eV, and some are even lower. The number of electrons with energy greater than 8.4eV is only 17.4%, while the number of electrons with electron energy between 2.0 and 8.4eV is as high as 58.3%. They become professional providers of energy for dissociated ozone. When the average energy of electrons in the discharge gap reaches 23eV, the number of electrons with energy ≥ 8.4eV increases to 80.0%, and the number of electrons with energy between 2.0 and 8.4eV decreases to 17.1%. This shows that the strong ionization discharge is beneficial to the generation of ozone, and the concentration of ozone is increased; at the same time, it inhibits the re-decomposition reaction of ozone.

The electric field strength expression in the discharge gap:

Eg＝V _m ε _d /(2l _d ε _g +lgε _d ) (5)

It can be seen from Equation 5 that only by increasing the applied peak voltage V _m and the dielectric constant ε _d of the dielectric, and reducing the distance of the discharge gap l _g and the thickness of the dielectric l _d , can the electric field intensity of a strong ionizing discharge be obtained.

Usually, the reduced electric field strength E/N (or E/P) is used to characterize the gas discharge strength and ionization strength. It will also indirectly characterize the concentration value of ozone. Figure 4 shows the relationship curve between the reduced electric field intensity and the average energy value obtained by electrons. It can be seen from the curve in Figure 4 that the average energy of electrons in the ionization discharge electric field depends on the strength of the ionization discharge electric field, and only the energy possessed by electrons in the process of strong ionization discharge can dissociate a large number of _O2 gas molecules into monatomic and monatomic ions and other active particles, and provide a large number of active particles and other basic materials for the synthesis of O ₃ .

According to Bernoulli's gas equation: Δp=C(-ΔV) ^-2 , the gas pressure in the discharge gap is inversely proportional to the square of the gas flow rate. Reduce the gas discharge gap distance, increase the gas flow rate in the discharge gap, increase the E/P (E/N) value, and the electrons in the discharge gap will increase their energy.

Because the utility model adopts a high-strength high-permittivity dielectric thin layer, that is, the thickness of the ceramic material is only 0.47-1.0 mm, and the discharge gap is extremely narrow, only 0.01-1.0 mm, so the equivalent electric field of the discharge gap is greatly improved. Intensity, and then double the occupancy rate of high-energy electrons in the discharge gap, as shown in Figure 2, and then greatly improve the ozone concentration and ozone generation efficiency.

Fig. 4 is a structural diagram of Embodiment 1 of the present utility model, and Fig. 5 is a cross-sectional view of N-N in Fig. 4 . In the above figure, 10 is an alternating high-voltage power supply with a frequency of 400-20000 Hz, which is connected to the discharge electrode 6 through a high-voltage cable 9 . A layer of Al ₂ O ₃ dielectric layer 5 with a thickness of 0.47-1.0 mm is pasted on both planes of the discharge electrode 6 corresponding to the ground electrode 3 . Several spacers 11 are placed between the dielectric layer 5 attached to the discharge electrode 6 and the corresponding ground electrode 3 to form two ultra-narrow discharge gaps 4 . When an alternating high voltage with a frequency of 400-20000Hz is applied to the discharge electrode 6, a strong ionizing discharge electric field is formed in the discharge gap 4, and the equivalent electric field strength E/n in the discharge channel reaches 450-1500Td; electrons have an average energy of 10- 24eV. The strong ionizing electric field will ionize, dissociate and excite oxygen 1 into a large number of high-concentration active particles; under the regulation of electric field parameters, high-concentration ozone 8 will be generated. And cooling with deionized water 2,7 simultaneously to discharge electrode 6, ground electrode 3, 2 is the deionized water of inlet, and 7 is the deionized water of outlet, and deionized water 7 reduces the cooling water temperature to setting by cooler 13 Fixed value, adjust the valve body 15, 16 according to the set value of the cooling water purity to determine the flow of the cooling water 7 passing through the ion exchanger 14; the cooled and deionized cooling water is injected into the ground electrode 3 and the discharge electrode 6.

Fig. 6 is the structure side view sectional view of embodiment 2 of the present utility model, and the difference between embodiment 2 and embodiment 1 is that the surface of discharge electrode 6 corresponding to ground electrode 3 is not attached to dielectric layer 5; However, the surface of the ground electrode 3 should be pasted with the dielectric layer 5 respectively.

Fig. 7 is a side view sectional view of the structure of Embodiment 3 of the present invention. The difference between Embodiment 3 and Embodiment 1 is that the surface of the ground electrode 3 corresponding to the discharge electrode 6 is also pasted with a layer of dielectric layer 5 respectively.

Claims (1)

1. a high-concentration ozone generating device is to be made of discharge electrode, earthing pole, dielectric layer, partition, it is characterized in that:

A: it is the Al of 0.47～1.0mm that smelting one layer thickness is pasted in the discharge electrode both sides ₂O ₃Dielectric layer;

B: forming distance with partition between the dielectric layer of discharge electrode and earthing pole is 0.04～0.25mm discharging gap;

C: discharge electrode, earthing pole two ends connect water cooler, and discharge electrode, earthing pole adopt the deionized water cooling;

D: the ozone concn of generation is 160～420g/Nm ³

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