A plasma tail gas treatment device and method based on porous materials

Abstract

The present invention provides a plasma tail gas treatment device based on porous materials, which includes a reaction device main body, a filter, a frequency modulation transformer, a porous ceramic plate, an array of needle-shaped high-voltage electrodes, a grounding electrode, and a gas mixing buffer chamber; a gas mixing buffer chamber is provided at the bottom of the reaction device main body, and the gas mixing buffer chamber is connected to the tail gas channel and the air channel; the filter is located at the front end of the tail gas channel; the array of needle-shaped high-voltage electrodes is arranged at the bottom of the reaction device main body and above the gas mixing buffer chamber; the frequency modulation transformer is connected to the array of needle-shaped high-voltage electrodes; the porous ceramic plate is arranged above the array of needle-shaped high-voltage electrodes; a liquid discharge pipe, a liquid injection pipe, and an exhaust pipe are sequentially arranged above the porous ceramic plate from bottom to top in the reaction device main body; the grounding electrode is installed in the reaction device main body and is placed above the porous part of the ceramic plate. The present invention effectively solves the problems of low treatment efficiency and insufficiency of gas pollutants in automobile exhaust.

Description

Technical Field

[0001] The invention belongs to the technical field of automobile exhaust treatment, and in particular relates to a plasma exhaust treatment device and method based on porous materials. Background Art

[0002] With the concentration of urban population and the development of science and technology, the number of cars is increasing. The emission of automobile exhaust has become one of the main sources of air pollution. Pollutants such as carbon monoxide, hydrocarbons and PM2.5 in exhaust are increasingly harmful to human health and environmental pollution. The problem of automobile exhaust pollution needs to be solved urgently.

[0003] At present, there are many theoretical ways to treat automobile exhaust. Among them, the use of clean fuel and the improvement of the structure of automobile fuel engines can fundamentally reduce the pollution of automobile exhaust to the environment compared with other treatment methods. The development and utilization of clean fuel effectively alleviate this problem. However, the current research on clean fuel is not sufficient, and the properties of clean fuel in existing research are still unstable. It has not completely replaced traditional fossil fuels. The development of clean fuel with higher combustion quality still faces many technical difficulties. At the same time, the improvement of the structure of fuel engines requires a long time and a lot of manpower and material resources. It is difficult to put it into production immediately, so it cannot be realized in the short term. The automobile exhaust purification device has a simple structure, a simple process, and a significant purification effect. Compared with fundamentally reducing exhaust pollution, the exhaust purification device can optimize the automobile exhaust treatment structure in a short period of time to reduce the pollution of harmful substances in the exhaust gas to the environment.

[0004] Automobile exhaust purification devices are mainly divided into two aspects: particulate pollutants and gaseous pollutants. For the treatment of particulate pollutants, the two methods widely used now include filtering catalytic oxidation and adsorption-combustion; for gaseous pollutants, three-way catalytic converters are widely used now. However, due to the high price of catalysts and the fact that exhaust gas from combustion treatment is prone to secondary pollution due to incomplete combustion, further research is needed to make up for the defects of various exhaust treatment methods. Summary of the invention

[0005] In view of the above problems existing in the traditional tail gas treatment method, the present invention proposes a plasma tail gas treatment device and method based on porous materials, which utilizes the oxidation-reduction and other activities of free radicals in the plasma to effectively treat gas pollutants such as carbon monoxide and hydrocarbons in automobile exhaust gas, and converts the gas pollutants into water and carbon dioxide through oxidation-reduction reactions and then discharges them into the atmospheric environment, thereby reducing the pollution of automobile exhaust gas to the atmosphere, optimizing the tail gas treatment structure, effectively solving the problems of low treatment efficiency and insufficiency of gas pollutants in automobile exhaust gas, reducing the treatment cost, expanding the application range, facilitating the realization of vehicle lightweight, and reducing carbon emissions.

[0006] The technical solution of the present invention is: a plasma tail gas treatment device based on porous materials, including a reaction device main body, a filter, a frequency modulation transformer, a porous ceramic plate, an array of needle-shaped high-voltage electrodes, a grounding electrode and a gas mixing buffer chamber; a gas mixing buffer chamber is provided at the bottom of the reaction device main body, and the gas mixing buffer chamber is connected to an exhaust gas channel and an air channel; the filter is located at the front end of the exhaust gas channel; the array of needle-shaped high-voltage electrodes is arranged at the bottom of the reaction device main body and above the gas mixing buffer chamber; the frequency modulation transformer is connected to the array of needle-shaped high-voltage electrodes; the porous ceramic plate is arranged above the array of needle-shaped high-voltage electrodes; a liquid discharge pipe, a liquid injection pipe and an exhaust pipe are successively arranged above the reaction device main body from bottom to top; the grounding electrode is installed in the reaction device main body, directly above the porous part of the ceramic plate, and the grounding electrode is spatially between the liquid injection pipe and the exhaust pipe and close to the liquid level.

[0007] In the above solution, a circulating water cooling device is further included; the circulating water cooling device is installed on the outer surface of the reaction device main body; the circulating water cooling device is provided with a condensed water inlet and a condensed water outlet.

[0008] In the above solution, the circulating water cooling device is connected to an on-vehicle circulating cooling water device.

[0009] In the above solution, the array of needle-shaped high-voltage electrodes includes a plurality of needle-shaped high-voltage electrodes arranged in an array, and the top of each needle-shaped high-voltage electrode respectively passes through the corresponding hole on the porous ceramic plate.

[0010] In the above solution, the grounding electrode is a plate-shaped electrode.

[0011] A method according to the plasma tail gas treatment device based on porous materials includes the following steps:

[0012] Water enters the main body of the reaction device through the liquid injection pipeline; the tail gas first passes through the filter on the tail gas channel to filter particulate pollutants, and then the tail gas and air are premixed in the gas mixing buffer chamber. After being charged by the array of needle-shaped high-voltage electrodes, it passes through the porous ceramic plate and enters the plasma reaction device main body in the form of uniform microbubbles. The poorly water-soluble carbon monoxide pollutant will pass through the free radical active particle layer formed under the action of the high-voltage pulse electric field at the liquid surface during the upward floating process away from the solution, and undergo a sufficient oxidation reaction to generate carbon dioxide and water. Finally, the carbon dioxide is discharged from the reaction device main body through the exhaust pipeline.

[0013] In the above solution, it further includes a cooling step: the circulating water cooling device is installed on the outer surface of the main body of the reaction device, and circulating cooling water is injected into the circulating water cooling device to cool the main body of the reaction device.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention uses a porous ceramic plate as the bubbling device, which can, on the premise of ensuring a large ventilation flow rate, make the tail gas enter the reaction device in the form of uniform micro-sized bubbles after being uniformly charged by the array of needle-shaped electrodes, expand the flow rate of tail gas treatment, improve the formation efficiency of low-temperature plasma, and thus effectively improve the tail gas treatment efficiency of the device. The grounding electrode is close to the liquid surface. Since a large amount of plasma can be generated at the liquid surface by high-voltage pulsed discharge, the purification efficiency of the tail gas can be ensured. Circulating cooling water is injected into the circulating water cooling device to cool the main body of the reaction device to ensure the treatment effect on tail gas pollutants. Before the tail gas enters the reaction device, air is premixed with the tail gas to effectively cool the tail gas and significantly increase the oxygen content of the tail gas, promoting the generation of free radical active particles in the reactor. Different from traditional tail gas treatment technologies, the reaction solution in the low-temperature plasma generating device of the present invention is water, which has low cost, is easy to replace, and is not likely to cause secondary pollution; due to the simple structure of the present invention, it is convenient for maintenance, reducing the maintenance cost. At the same time as the plasma is generated by high-voltage pulsed discharge in water, the generated shock wave can clean the inner wall of the reaction vessel of the device, preventing the blockage and aging of the container pipeline; due to the simple structure, convenient maintenance, low cost and low requirement for the air-fuel ratio of the vehicle of the present invention, it has great practical application potential. Description of the Drawings

[0015] Figure 1 It is a schematic structural view of a plasma tail gas treatment device based on porous materials according to an embodiment of the present invention.

[0016] Figure 2 It is an external view of the bottom porous ceramic plate in the reaction device according to an embodiment of the present invention.

[0017] Figure 3 It is a cross-sectional view of the porous ceramic plate and the array of needle-shaped high-voltage electrodes according to an embodiment of the present invention.

[0018] In the figure, 1. Filter, 2. Frequency modulation transformer, 3. Porous ceramic plate, 4. Array type needle-shaped high voltage electrode, 5. Ground electrode, 6. External circulating water cooling device, 7. Gas mixing buffer chamber, 8. Liquid injection pipeline, 9. Liquid discharge pipeline; 10. Exhaust pipeline, 11. Condensate inlet, 12. Condensate outlet, 13. Tail gas channel, 14. Air channel. Specific embodiments

[0019] Embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary and are intended to explain the present invention and should not be construed as limiting the present invention.

[0020] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "axial", "radial", "vertical", "horizontal", "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality" means two or more unless otherwise specifically defined.

[0021] In the present invention, unless otherwise clearly specified and defined, the terms "mounted", "connected", "connected to", "fixed", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0022] Figures 1-3Shown is a preferred embodiment of the plasma tail gas treatment device based on porous materials according to the present invention. The plasma tail gas treatment device based on porous materials includes a reaction device main body, a filter 1, a frequency modulation transformer 2, a porous ceramic plate 3, an array of needle-shaped high-voltage electrodes 4, a grounding electrode 5, and a gas mixing buffer chamber 7. A gas mixing buffer chamber 7 is provided at the bottom of the reaction device main body, and the gas mixing buffer chamber 7 is connected to a tail gas passage 13 and an air passage 14. The filter 1 is located at the front end of the tail gas passage 13. The array of needle-shaped high-voltage electrodes 4 is arranged at the bottom of the reaction device main body and above the gas mixing buffer chamber 7. The frequency modulation transformer 2 is connected to the array of needle-shaped high-voltage electrodes 4. The porous ceramic plate 3 is arranged above the array of needle-shaped high-voltage electrodes 4. The array of needle-shaped high-voltage electrodes 4 includes a plurality of needle-shaped high-voltage electrodes arranged in an array, and the top of each needle-shaped high-voltage electrode respectively passes through the corresponding hole on the porous ceramic plate 3. A liquid discharge pipe 9, a liquid injection pipe 8, and an exhaust pipe 10 are successively arranged above the porous ceramic plate 3 from bottom to top in the reaction device main body. The grounding electrode 5 is installed in the reaction device main body, directly above the porous part of the porous ceramic plate 3. The grounding electrode 5 is spatially between the liquid injection pipe 8 and the exhaust pipe 10 and close to the liquid level position.

[0023] According to this embodiment, preferably, a circulating water cooling device 6 is further included. The circulating water cooling device 6 is installed on the outer surface of the reaction device main body. The circulating water cooling device 6 is provided with a condensed water inlet 11 and a condensed water outlet 12.

[0024] According to this embodiment, preferably, the circulating water cooling device 6 is connected to a vehicle-mounted circulating cooling water device.

[0025] According to this embodiment, preferably, the grounding electrode 5 is a plate-shaped electrode.

[0026] A method according to the plasma tail gas treatment device based on porous materials includes the following steps:

[0027] Water enters the reaction device main body through the liquid injection pipe 8. The tail gas first passes through the filter 1 on the tail gas passage 13 to filter particulate pollutants, and then the tail gas is premixed with air in the gas mixing buffer chamber 7. After being charged by the array of needle-shaped high-voltage electrodes 4, it passes through the porous ceramic plate 3 and enters the plasma reaction device main body in the form of uniform microbubbles. The poorly water-soluble carbon monoxide pollutant will pass through the free radical active particle layer formed under the action of the high-voltage pulse electric field at the liquid surface during the process of floating upward and leaving the solution, and undergo a sufficient oxidation reaction to generate carbon dioxide and water. Finally, the carbon dioxide is discharged from the exhaust pipe 10 out of the reaction device main body. The circulating water cooling device 6 is installed on the outer surface of the reaction device main body, and circulating cooling water is injected into the circulating water cooling device 6 to cool the reaction device main body.

[0028] The porous ceramic plate 3 is arranged at the bottom of the reaction device main body, which can increase the ventilation flow rate of the device and enable the to-be-treated tail gas discharged to fully react in the reaction device, and completely generate harmless gases such as carbon dioxide before being discharged from the reaction device.

[0029] The filter 1 is placed at the front end of the tail gas passage 13, which can filter out particulate pollutants in the tail gas, facilitating more thorough treatment of gaseous pollutants in the tail gas later.

[0030] The frequency modulation transformer 2 is connected to the vehicle engine, providing a high-voltage pulsed power supply for the tail gas treatment device, which provides a prerequisite for the generation of plasma and the treatment of tail gas by active ions.

[0031] In the porous ceramic plate 3, the arrayed needle-shaped high-voltage electrode 4 connected to the frequency modulation transformer 2 is used as the high-voltage electrode of the reaction device, enabling the tail gas to be fully charged before entering the plasma reaction device main body. After entering the container in the form of bubbles, the oxidizing property of active particles can be used to more fully treat carbon monoxide, hydrocarbons and other substances in the tail gas.

[0032] The grounding electrode 5 is placed directly above the porous ceramic plate 3, close to the liquid surface of the solution, and plasma will be generated at the liquid surface. Since gas pollutants such as carbon monoxide and hydrocarbons are insoluble in water, they will leave the solution after floating and rising, ensuring that the gas pollutants are fully oxidized into carbon dioxide and water when leaving the liquid surface, and ensuring the treatment efficiency of the tail gas to a certain extent.

[0033] The present invention uses high-voltage pulsed discharge to generate plasma as the main technical means. Utilizing the oxidation activity of active particles such as free radicals, which are easy to react with other substances to form stable molecules, to treat gas pollutant components such as carbon monoxide in the tail gas. The vehicle engine is used as the power supply, and the frequency modulation transformer 2 is used to convert the output voltage into a high-voltage pulsed voltage. The instantaneous strong electric field formed by the high-voltage pulsed power supply can enable electrons to obtain energy and collide with surrounding molecules, thereby forming active particles or free radicals. The to-be-treated tail gas is pre-mixed with air to reduce the reaction temperature of the tail gas, which is beneficial to the treatment of the tail gas. At the same time, it can increase the oxygen content in the reaction device main body and improve the formation efficiency of free radical active particles. Using the arrayed needle-shaped high-voltage electrode 4 as the high-voltage electrode, and utilizing the porous structure of the porous ceramic plate 3 in the form of the bubbling method, the to-be-treated tail gas is uniformly charged in the form of uniform micro-bubbles and then introduced into the reaction device main body, thereby improving the tail gas treatment efficiency.

[0034] The present invention uses water as the continuous liquid phase, which is different from the situation where the catalyst cost is relatively high and the catalytic effect will be reduced if it is not replaced in time after long-term use; and the combustion treatment may cause secondary pollution due to incomplete combustion, and the generated particulate matter may cause blockage of the ventilation pipeline. Using water as the reaction solution, the reaction treatment is more environmentally friendly and effective, and is not likely to cause secondary pollution. A particulate filter 1 is installed at the tail gas inlet to improve the pertinence of the device for treating gas pollutants and facilitate the centralized treatment of particulate pollutants. Compared with a DC power supply, using a high-voltage pulsed power supply to discharge in water can reduce power consumption and is more conducive to the preparation of the required plasma. In the device of the present invention, if the temperature is too high, it will not be conducive to the progress of the tail gas treatment oxidation reaction, and there will be potential safety hazards. Therefore, an external circulating water cooling device 6 is provided outside the plasma generator reactor, and circulating cooling water is injected to cool the plasma generating device to ensure the generation efficiency of active particles and ensure the effective treatment of gas pollutants. The porous ceramic plate 3 can make the gas enter the treatment device in the form of small bubbles with uniform sizes, expand the flow rate of the tail gas treatment, improve the formation efficiency of the non-thermal plasma, and thus effectively improve the tail gas treatment efficiency of the device.

[0035] The series of detailed descriptions listed above are only specific descriptions of the feasible embodiments of the present invention, and they are not intended to limit the protection scope of the present invention. Any equivalent embodiments or changes made without departing from the technical spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A plasma tail gas treatment device based on porous materials, characterized in that, it includes a reaction device main body, a filter (1), a frequency modulation transformer (2), a porous ceramic plate (3), an array-type needle-shaped high-voltage electrode (4), a grounding electrode (5), and a gas mixing buffer chamber (7); A gas mixing buffer chamber (7) is provided at the bottom of the reaction device main body, and the gas mixing buffer chamber (7) is connected to an exhaust gas channel (13) and an air channel (14); the filter (1) is located at the front end of the exhaust gas channel (13); The array-type needle-shaped high-voltage electrode (4) is arranged at the bottom of the reaction device main body and above the gas mixing buffer chamber (7); the frequency modulation transformer (2) is connected to the array-type needle-shaped high-voltage electrode (4); the porous ceramic plate (3) is arranged above the array-type needle-shaped high-voltage electrode (4); a liquid discharge pipe (9), a liquid injection pipe (8), and an exhaust pipe (10) are successively arranged from bottom to top above the reaction device main body and above the porous ceramic plate (3); the grounding electrode (5) is installed in the reaction device main body, directly above the porous part of the porous ceramic plate (3), and the grounding electrode (5) is spatially between the liquid injection pipe (8) and the exhaust pipe (10) and close to the liquid level position; The grounding electrode (5) is a plate-shaped electrode; The frequency modulation transformer (2) is connected to a vehicle engine.

2. The plasma tail gas treatment device based on porous materials according to claim 1, characterized in that, it further includes a circulating water cooling device (6); the circulating water cooling device (6) is installed on the outer surface of the reaction device main body; the circulating water cooling device (6) is provided with a condensed water inlet (11) and a condensed water outlet (12).

3. The plasma tail gas treatment device based on porous materials according to claim 2, characterized in that, The circulating water cooling device (6) is connected to a vehicle circulating cooling water device.

4. The plasma tail gas treatment device based on porous materials according to claim 1, characterized in that, The array-type needle-shaped high-voltage electrode (4) includes a plurality of array-type arranged needle-shaped high-voltage electrodes, and the top of each needle-shaped high-voltage electrode respectively passes through the corresponding holes on the porous ceramic plate (3).

5. A method for the plasma tail gas treatment device based on porous materials according to claim 1, characterized in that, it includes the following steps: Water enters the reaction device main body through the liquid injection pipe (8); the tail gas first passes through the filter (1) on the exhaust gas channel (13) to filter particulate pollutants, then the tail gas and air are premixed in the gas mixing buffer chamber (7), and then after being charged by the array-type needle-shaped high-voltage electrode (4), it passes through the porous ceramic plate (3) and enters the plasma reaction device main body in the form of uniform microbubbles. The poorly water-soluble carbon monoxide pollutant will pass through the free radical active particle layer formed under the action of a high-voltage pulse electric field at the liquid level during the process of floating upward and leaving the solution, and undergo a sufficient oxidation reaction to generate carbon dioxide and water. Finally, the carbon dioxide is discharged from the exhaust pipe (10) out of the reaction device main body.

6. The method of the plasma tail gas treatment device based on porous materials according to claim 5, characterized in that, it further includes a cooling step: a circulating water cooling device (6) is installed on the outer surface of the reaction device main body, and circulating cooling water is injected into the circulating water cooling device (6) to cool the reaction device main body.

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