Low-temperature plasma-catalysis synergistic tail gas purification device and method

Abstract

The application relates to the field of internal combustion engine exhaust purification technology and discloses a low-temperature plasma-catalysis exhaust purification device and method, which comprises a body, and a filtering unit, a reaction unit and a catalysis unit are sequentially arranged in the body along the exhaust flow direction. The multi-layer filter screen of the filtering unit intercepts large-particle dust and soot in the exhaust, high-energy electrons and active free radicals are generated in the high-voltage electric field of the reaction unit to charge and break the soot particles, nitrogen oxides, carbon monoxide and hydrocarbons are preliminarily oxidized and activated, the nitrogen oxides treated by the reaction unit are selectively catalytically reduced into harmless nitrogen and water by the action of a manganese-copper-rare earth composite catalyst in the catalysis unit, the carbon monoxide and hydrocarbons are deeply oxidized into carbon dioxide and water, and the charged and broken soot particles are deeply oxidized into carbon dioxide, so that the gaseous pollutants and particulate matters in the exhaust of the underground diesel vehicle are synergistically and efficiently removed.

Description

Technical Field

[0001] This invention relates to the field of internal combustion engine exhaust gas purification technology, and in particular to a low-temperature plasma synergistic catalytic exhaust gas purification device and method. Background Technology

[0002] Diesel vehicles in coal mines are the core power equipment for underground transportation operations. They operate for long periods in harsh environments with low temperatures of 80-180℃, high humidity of 70%-95%, and the coexistence of methane and coal dust, which are flammable and explosive. The operating load fluctuates frequently, and their exhaust gas contains a variety of toxic and harmful pollutants such as PM particles, nitrogen oxides, carbon monoxide, and hydrocarbons. This can easily cause the air quality in underground roadways to deteriorate, threatening the health of underground workers and the safe production of the mine.

[0003] Existing exhaust gas purification equipment mainly includes diesel particulate filters and selective catalytic reduction devices. Diesel particulate filters intercept soot particles through porous ceramic wall-flow filters, while selective catalytic reduction devices rely on ammonia generated by the pyrolysis of urea aqueous solution to reduce nitrogen oxides to nitrogen and water under the action of a catalyst. The two are usually installed in series in the exhaust pipeline, respectively undertaking the functions of particulate matter removal and gaseous pollutant treatment, thereby achieving the step-by-step purification treatment of harmful components in exhaust gas.

[0004] However, in actual use underground, the exhaust temperature remains in a low-temperature range for extended periods, preventing the diesel particulate filter from reaching the sustained high-temperature conditions required for passive regeneration. As the collected carbon soot particles gradually accumulate, the back pressure rises sharply, forcing a decrease in engine power and an increase in fuel consumption. At the same time, the low-temperature exhaust also leads to insufficient pyrolysis of urea in the selective catalytic reduction device, which easily generates solid byproducts such as biuret and cyanuric acid that clog the catalyst channels, causing a rapid decline in catalytic activity. Consequently, it is difficult to meet the core requirement of underground vehicles for integrated and efficient purification of particulate matter and gaseous pollutants. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a low-temperature plasma synergistic catalytic tail gas purification device and method.

[0006] This invention provides a low-temperature plasma synergistic catalytic exhaust gas purification device for purifying exhaust gas emitted by diesel vehicles in underground mines. The device includes a main body, and the interior of the main body is provided with a filter unit, a reaction unit and a catalytic unit in sequence along the exhaust gas flow direction. The filtration unit includes multiple layers of filter screens disposed within the main body, which are used to intercept large particles of dust and soot in the exhaust gas. The reaction unit includes an insulating dielectric tube fixed inside the main body, a high-voltage electrode arranged along the central axis of the insulating dielectric tube, and a grounding electrode disposed on the outer wall of the insulating dielectric tube. A discharge gap is formed between the high-voltage electrode and the grounding electrode. After the high-voltage electrode is energized, a high-voltage electric field is formed in the discharge gap. Under the action of the high-voltage electric field, high-energy electrons and active free radicals are generated to charge and break down the particulate matter in the filtered exhaust gas and to perform preliminary oxidation and activation of the gaseous pollutants in the exhaust gas. The catalytic unit includes a catalyst support fixed within the main body. The catalyst support is filled with a manganese-copper-rare earth composite catalyst, which is used to selectively catalytically reduce nitrogen oxides in the gaseous pollutants after the initial oxidation and activation of the reaction unit to nitrogen and water, and to deeply oxidize carbon monoxide and hydrocarbons to carbon dioxide and water, while simultaneously deeply oxidizing the charged and broken particulate matter to carbon dioxide.

[0007] Furthermore, the high-voltage electrode is electrically connected to the vehicle-mounted high-voltage pulse power supply, the surface of the high-voltage electrode is coated with an alumina-cerium oxide composite ceramic coating, and the discharge gap is gradually set along the exhaust gas flow direction.

[0008] Furthermore, the multi-layered filter screen is arranged perpendicular to the exhaust gas flow direction, and a pressure relief valve is provided on the air inlet side of the multi-layered filter screen, the pressure relief valve being embedded in the inner wall of the main body.

[0009] Furthermore, a dehumidification unit is provided between the filtration unit and the reaction unit. The dehumidification unit includes a hydrophobic ceramic filter element that is detachably installed inside the main body. The hydrophobic ceramic filter element is sealed and fitted to the inner wall of the main body. The surface of the hydrophobic ceramic filter element is provided with a hydrophobic modified coating. The hydrophobic ceramic filter element is used to reduce the relative humidity of the exhaust gas.

[0010] Furthermore, a decomposition unit is provided at the end of the catalytic unit. The decomposition unit includes an ozone catalytic carrier fixed within the main body. The ozone catalytic carrier is filled with an ozone decomposition catalyst, which is used to catalytically decompose the ozone byproducts generated by gaseous pollutants in the exhaust gas under the action of a high-voltage electric field into oxygen.

[0011] Furthermore, the manganese-copper-rare earth composite catalyst is a honeycomb ceramic supported catalyst.

[0012] Furthermore, the air inlet end and air outlet end of the main body are respectively connected to an air inlet connector and an air outlet connector. The air inlet connector is sealed to the diesel engine exhaust pipe, and the air outlet connector directly discharges the purified exhaust gas into the atmosphere or connects to the subsequent exhaust pipe.

[0013] Furthermore, the body is provided with an integrated explosion-proof housing, which is a sealed explosion-proof structure, and the maximum operating temperature of the surface of the explosion-proof housing is ≤150℃.

[0014] Furthermore, a controller is installed on the outside of the explosion-proof housing. The controller has a built-in temperature and humidity sensor and an electrical parameter acquisition module. The detection end of the temperature and humidity sensor extends into the interior of the main body. The controller is electrically connected to the vehicle-mounted high-voltage pulse power supply, the temperature and humidity sensor, and the electrical parameter acquisition module.

[0015] A low-temperature plasma-assisted catalytic tail gas purification method includes the following steps: The exhaust gas emitted by the underground diesel vehicle enters the body and is filtered by the multi-layer filter to intercept large particles of dust and soot. After preliminary filtration, the exhaust gas enters the reaction unit. After the high-voltage electrode is energized, a high-voltage electric field is formed in the discharge gap between the high-voltage electrode and the grounding electrode. Under the action of the high-voltage electric field, high-energy electrons and active free radicals are generated to charge and break down the particulate matter in the filtered exhaust gas and to perform preliminary oxidation and activation of the gaseous pollutants in the exhaust gas. Particulate matter and gaseous pollutants in the exhaust gas after treatment in the reaction unit enter the catalytic unit. Under the action of manganese-copper-rare earth composite catalyst in the catalyst carrier, nitrogen oxides that have been initially oxidized and activated are selectively catalytically reduced to nitrogen and water, carbon monoxide and hydrocarbons are deeply oxidized to carbon dioxide and water, and carbon soot particles that have been charged and crushed are deeply oxidized to carbon dioxide. The purified exhaust gas is finally discharged to the outside.

[0016] Compared with the prior art, the technical solution provided by the embodiments of the present invention has the following advantages: The present invention intercepts large particulate dust and soot in the exhaust gas through the multi-layer filter screen of the filter unit, avoiding the entry of particulate matter into subsequent units and causing blockage. The high-voltage electric field of the reaction unit generates high-energy electrons and active free radicals to charge and break down the soot particles, reducing their particle size and increasing their specific surface area, which facilitates subsequent catalytic oxidation. At the same time, nitrogen oxides, carbon monoxide and hydrocarbons are initially oxidized and activated. Then, through the action of the manganese-copper-rare earth composite catalyst in the catalytic unit, the nitrogen oxides treated by the reaction unit are selectively catalytically reduced to harmless nitrogen and water, and carbon monoxide and hydrocarbons are deeply oxidized to carbon dioxide and water. At the same time, the charged and broken soot particles are deeply oxidized to carbon dioxide, thereby achieving synergistic and efficient removal of particulate matter and gaseous pollutants in the exhaust gas of underground diesel vehicles, significantly improving the purification efficiency. Attached Figure Description

[0017] Figure 1 This is a cross-sectional view of the overall structure of a low-temperature plasma synergistic catalytic tail gas purification device provided in an embodiment of the present invention.

[0018] Explanation of reference numerals in the attached figures: 1. Body; 2. Filter unit; 21. Filter screen; 22. Pressure relief valve; 3. Hydrophobic ceramic filter element; 4. Reaction unit; 41. Insulating medium tube; 42. High voltage electrode; 43. Grounding electrode; 44. Discharge gap; 5. Catalyst carrier; 6. Ozone catalytic carrier; 7. Inlet connector; 8. Outlet connector; 9. Explosion-proof housing. Detailed Implementation

[0019] The following detailed description of a specific embodiment of the present invention is provided in conjunction with the accompanying drawings. However, it should be understood that the scope of protection of the present invention is not limited to the specific embodiment.

[0020] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the technical solution of this 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. Therefore, they should not be construed as limitations on this invention.

[0021] The present invention will be described below through several specific embodiments. To keep the following description of the embodiments clear and concise, detailed descriptions of known functions and components may be omitted. When any component of an embodiment of the present invention appears in more than one drawing, the component may be represented by the same reference numerals in each drawing.

[0022] like Figure 1 As shown in the figure, an embodiment of the present invention provides a method for purifying exhaust gas emitted by diesel vehicles in underground mines, comprising a body 1, wherein a filter unit 2, a reaction unit 4 and a catalytic unit are sequentially arranged inside the body 1 along the exhaust gas flow direction. The filter unit 2 includes a multi-layer filter screen 21 fixedly installed inside the main body 1. The multi-layer filter screen 21 is used to intercept large particulate dust and soot in the exhaust gas. The reaction unit 4 includes an insulating dielectric tube 41 fixed inside the body 1, a high-voltage electrode 42 arranged along the central axis of the insulating dielectric tube 41, and a grounding electrode 43 arranged on the outer wall of the insulating dielectric tube 41. A discharge gap 44 is formed between the high-voltage electrode 42 and the grounding electrode 43. After the high-voltage electrode 42 is energized, a high-voltage electric field is formed in the discharge gap 44. Under the action of the high-voltage electric field, high-energy electrons and active free radicals are generated to charge and break down the particulate matter in the filtered exhaust gas and to perform preliminary oxidation and activation of the gaseous pollutants in the exhaust gas. The catalytic unit includes a catalyst support 5 fixed in the body 1. The catalyst support 5 is filled with a manganese-copper-rare earth composite catalyst, which is used to selectively catalytically reduce nitrogen oxides in the gaseous pollutants after the initial oxidation and activation of the reaction unit 4 to nitrogen and water, and to deeply oxidize carbon monoxide and hydrocarbons to carbon dioxide and water, while deeply oxidizing the charged and broken particulate matter to carbon dioxide. After the exhaust gas from the underground diesel vehicle enters the main body 1, it first passes through the multi-layer filter screen 21 of the filter unit 2 to intercept large particles of dust and soot. The filtered exhaust gas then enters the reaction unit 4. When the high-voltage electrode 42 is energized, a high-voltage electric field is formed in the discharge gap 44 between the high-voltage electrode 42 and the ground electrode 43. Under the action of the high-voltage electric field, high-energy electrons and active free radicals are generated, which charge and break down the filtered soot particles, reducing their particle size to facilitate subsequent catalytic oxidation. At the same time, nitrogen oxides, carbon monoxide, and hydrocarbons undergo preliminary oxidation and activation. The exhaust gas treated by the reaction unit 4 then enters the catalytic unit, where manganese... Under the action of the copper-rare earth composite catalyst, the exhaust pollutants treated by reaction unit 4 undergo deep catalytic oxidation and reduction reactions, degrading most of the harmful pollutants. The nitrogen-hydrogen compounds and carbon monoxide contained in the exhaust gas are used as reducing agents to selectively catalytically reduce nitrogen oxides to harmless nitrogen and water, and to deeply oxidize the residual carbon monoxide and hydrocarbons in the exhaust gas to carbon dioxide and water. At the same time, the charged and broken particulate matter is deeply oxidized to carbon dioxide. Finally, the clean exhaust gas is discharged, thereby achieving the synergistic and efficient removal of particulate matter and gaseous pollutants in the exhaust gas of underground diesel vehicles.

[0023] Furthermore, such as Figure 1 As shown, the high-voltage electrode 42 is electrically connected to the vehicle-mounted high-voltage pulse power supply. The surface of the high-voltage electrode 42 is coated with an alumina-cerium oxide composite ceramic coating, and the discharge gap 44 is set in a gradually changing manner along the exhaust gas flow direction. The alumina-cerium oxide composite ceramic coating on the surface of the high-voltage electrode 42 can effectively suppress the surface oxidation and corrosion of the high-voltage electrode 42 during the pulse discharge process by utilizing the high dielectric strength, high temperature resistance and electrochemical corrosion resistance of ceramic materials, thus extending the electrode life and maintaining stable discharge performance. The gradually changing discharge gap 44 along the exhaust gas flow direction allows the electric field strength to gradually change along the airflow direction, matching the oxidation requirements of different particle sizes and pollutants of different concentrations in the exhaust gas. This avoids local over-strong or under-weak discharge caused by a single gap, thereby improving energy utilization efficiency while ensuring the uniformity of plasma distribution throughout the reaction area and ensuring the consistency of exhaust gas purification effect.

[0024] Furthermore, such as Figure 1As shown, the multi-layer filter screen 21 is set perpendicular to the exhaust gas flow direction, and a pressure relief valve 22 is provided on the air inlet side of the multi-layer filter screen 21. The pressure relief valve 22 is embedded in the inner wall of the main body 1. The vertical airflow arrangement of the multi-layer filter screen 21 can intercept large dust and carbon soot particles in the exhaust gas step by step, thereby improving the solid impurity interception efficiency. At the same time, the pressure relief valve 22 can quickly release pressure to block the flame propagation in the event of backfire, thereby ensuring the safety of downhole operations.

[0025] Furthermore, such as Figure 1 As shown, a dehumidification unit is provided between the filtration unit 2 and the reaction unit 4. The dehumidification unit includes a hydrophobic ceramic filter element 3 that is detachably installed inside the main body 1. The hydrophobic ceramic filter element 3 is sealed and fitted to the inner wall of the main body 1. The surface of the hydrophobic ceramic filter element 3 is provided with a hydrophobic modified coating. The hydrophobic ceramic filter element 3 is used to reduce the relative humidity of the exhaust gas. The hydrophobic ceramic filter element 3 prevents water vapor from condensing on the filter element surface to form a water film through the surface hydrophobic modified coating, keeps the gas passage unobstructed, and reduces the relative humidity of the exhaust gas, thereby ensuring the stability of the subsequent plasma discharge and the activity of the catalyst.

[0026] Furthermore, such as Figure 1 As shown, a decomposition unit is provided at the end of the catalytic unit. The decomposition unit includes an ozone catalytic carrier 6 fixed inside the main body 1. The ozone catalytic carrier 6 is filled with an ozone decomposition catalyst, which is used to catalytically decompose the ozone byproducts generated by gaseous pollutants in the exhaust gas under the action of a high-voltage electric field into oxygen. The ozone decomposition catalyst filled in the ozone catalytic carrier 6 can catalytically decompose the ozone byproducts generated by gaseous pollutants in the exhaust gas under the action of a high-voltage electric field into oxygen, effectively eliminating secondary pollution caused by ozone emissions, ensuring that the purified exhaust gas meets environmental safety standards, and thus protecting the health of underground workers.

[0027] Furthermore, such as Figure 1 As shown, the manganese-copper-rare earth composite catalyst is a honeycomb ceramic support catalyst. The honeycomb ceramic support supported manganese-copper-rare earth composite catalyst has the characteristics of large specific surface area and high mass transfer efficiency. The honeycomb structure can significantly reduce the exhaust gas flow resistance, thereby improving the catalytic reaction efficiency.

[0028] Furthermore, such as Figure 1 As shown, the intake end and exhaust end of the main body 1 are respectively connected to an intake connector 7 and an exhaust connector 8. The intake connector 7 is sealed to the exhaust pipe of the diesel engine, and the exhaust connector 8 directly discharges the purified exhaust gas into the atmosphere or connects to the subsequent exhaust pipe. The intake connector 7 and the exhaust connector 8 are coaxially connected to each unit to ensure that the exhaust gas flows smoothly along the axis of the device, reducing airflow resistance and energy loss. The intake connector 7 is sealed to the engine exhaust pipe to prevent air leakage, while the exhaust connector 8 can be directly discharged or connected to the subsequent pipeline to adapt to different emission requirements, thereby achieving flexible and reliable exhaust gas purification and transportation.

[0029] Furthermore, such as Figure 1 As shown, the body 1 is provided with an integrated explosion-proof housing 9. The explosion-proof housing 9 is a sealed explosion-proof structure, and the maximum operating temperature of the surface of the explosion-proof housing 9 is ≤150℃. The explosion-proof housing 9 adopts a sealed explosion-proof structure, which can seal the electric sparks or high-temperature gases that may be generated inside the body 1 within the explosion-proof housing 9, preventing the ignition of external flammable and explosive gases. At the same time, the maximum operating temperature of the surface of the explosion-proof housing 9 does not exceed 150℃, further reducing the risk of hot surface ignition, thereby ensuring the safe use of the device in dangerous environments such as underground mines.

[0030] Furthermore, such as Figure 1 As shown, the effective operating temperature range inside the body 1 is 80℃~180℃, which is used to simultaneously remove particulate matter, nitrogen oxides, carbon monoxide and hydrocarbons from the exhaust gas. The effective operating temperature range of 80℃-180℃ inside the body 1 allows the manganese-copper-rare earth catalyst to maintain its optimal catalytic activity within this temperature window, thereby ensuring that the components of the exhaust gas after plasma activation can fully react on the catalyst surface, achieving simultaneous and efficient removal of particulate matter, nitrogen oxides, carbon monoxide and hydrocarbons.

[0031] Furthermore, such as Figure 1 As shown, a controller (not shown in the figure) is installed on the outside of the explosion-proof housing 9. The controller has a built-in temperature and humidity sensor and an electrical parameter acquisition module. The detection end of the temperature and humidity sensor extends into the interior of the main body 1. The controller is electrically connected to the vehicle-mounted high-voltage pulse power supply, the temperature and humidity sensor, and the electrical parameter acquisition module. The controller monitors the exhaust conditions inside the main body 1 in real time through the built-in temperature and humidity sensor, and monitors the discharge state of the high-voltage pulse power supply in conjunction with the electrical parameter acquisition module. Based on the feedback signal, the controller adaptively adjusts the power output parameters to match the plasma discharge energy with the changes in exhaust gas composition, thereby achieving efficient purification and stable operation under all operating conditions.

[0032] like Figure 1 As shown, a low-temperature plasma-assisted catalytic tail gas purification method includes the following steps: Flame arrestor and primary filter: The intake connector 7 is sealed to the engine exhaust pipe. The exhaust gas from the diesel vehicle in the well enters the main body 1. First, it passes through the multi-layer filter screen 21 of the filter unit 2 to intercept large particles of dust and soot. Then, the pressure relief valve 22 quickly releases pressure to block the flame propagation when backfire occurs, ensuring the safety of the well operation. Dehumidification and drying: The exhaust gas after preliminary filtration enters the dehumidification unit and reduces the relative humidity of the exhaust gas by passing through the hydrophobic ceramic filter element 3. The hydrophobic modified coating on the surface of the hydrophobic ceramic filter element 3 prevents water vapor from condensing on the filter element surface to form a water film, keeps the gas passage unobstructed, and avoids water vapor from interfering with the stability of subsequent plasma discharge and catalyst activity. Low-temperature plasma activation: After dehumidification, the exhaust gas enters the reaction unit 4. The controller adaptively adjusts the output voltage and frequency of the on-board high-voltage pulse power supply according to the exhaust conditions fed back by the temperature and humidity sensor. The discharge gap 44 between the high-voltage electrode 42 and the ground electrode 43 forms a high-voltage electric field. The discharge gap 44, which is set in a gradually changing manner along the exhaust gas flow direction, gradually adjusts the electric field intensity distribution with the airflow direction, generating high-energy electrons and active free radicals, charging and breaking down the carbon soot particles in the exhaust gas, reducing their particle size to facilitate subsequent catalytic oxidation, and simultaneously performing preliminary oxidation and activation of nitrogen oxides, carbon monoxide and hydrocarbons in the exhaust gas. Catalytic purification: The exhaust gas after being treated by reaction unit 4 enters the catalytic unit. Under the catalytic action of the manganese-copper-rare earth composite catalyst supported by catalyst carrier 5, the pollutants in the exhaust gas after being treated by reaction unit 4 undergo deep catalytic oxidation and reduction reactions, degrading most of the harmful pollutants. Using the nitrogen and hydrogen compounds and carbon monoxide contained in the exhaust gas as reducing agents, nitrogen oxides are selectively catalytically reduced to harmless nitrogen and water, and the residual carbon monoxide and hydrocarbons in the exhaust gas are deeply oxidized to carbon dioxide and water. At the same time, the charged and crushed particulate matter is deeply oxidized to carbon dioxide. Ozone decomposition: The purified exhaust gas enters the decomposition unit, where the ozone decomposition catalyst in the ozone catalyst carrier 6 catalyzes and decomposes the ozone byproducts generated by the gaseous pollutants in the exhaust gas into oxygen under the action of a high voltage electric field, thus avoiding secondary pollution. Exhaust gas emissions: The treated clean exhaust gas is directly discharged into the atmosphere or enters the subsequent exhaust pipeline through the exhaust connector 8, realizing the synergistic and efficient removal of particulate matter and gaseous pollutants in the exhaust gas of underground diesel vehicles.

[0033] The above inventions are merely a few specific embodiments of the present invention. However, the embodiments of the present invention are not limited thereto, and any variations that can be conceived by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. A low-temperature plasma-assisted catalytic exhaust gas purification device for purifying exhaust gas emitted from underground diesel vehicles, characterized in that, The main body includes a filter unit, a reaction unit, and a catalytic unit arranged sequentially inside the main body along the exhaust gas flow direction; The filtration unit includes multiple layers of filter screens disposed within the main body, which are used to intercept large particles of dust and soot in the exhaust gas. The reaction unit includes an insulating dielectric tube fixed inside the main body, a high-voltage electrode arranged along the central axis of the insulating dielectric tube, and a grounding electrode disposed on the outer wall of the insulating dielectric tube. A discharge gap is formed between the high-voltage electrode and the grounding electrode. After the high-voltage electrode is energized, a high-voltage electric field is formed in the discharge gap. Under the action of the high-voltage electric field, high-energy electrons and active free radicals are generated to charge and break down the particulate matter in the filtered exhaust gas and to perform preliminary oxidation and activation of the gaseous pollutants in the exhaust gas. The catalytic unit includes a catalyst support fixed within the main body. The catalyst support is filled with a manganese-copper-rare earth composite catalyst, which is used to selectively catalytically reduce nitrogen oxides in the gaseous pollutants after the initial oxidation and activation of the reaction unit to nitrogen and water, and to deeply oxidize carbon monoxide and hydrocarbons to carbon dioxide and water, while simultaneously deeply oxidizing the charged and broken particulate matter to carbon dioxide.

2. The low-temperature plasma synergistic catalytic tail gas purification device as described in claim 1, characterized in that, The high-voltage electrode is electrically connected to the vehicle-mounted high-voltage pulse power supply. The surface of the high-voltage electrode is coated with an alumina-cerium oxide composite ceramic coating, and the discharge gap is gradually set along the exhaust gas flow direction.

3. The low-temperature plasma synergistic catalytic tail gas purification device as described in claim 1, characterized in that, The multi-layered filter screen is arranged perpendicular to the exhaust gas flow direction, and a pressure relief valve is provided on the air inlet side of the multi-layered filter screen, the pressure relief valve being embedded in the inner wall of the main body.

4. The low-temperature plasma synergistic catalytic tail gas purification device as described in claim 1, characterized in that, A dehumidification unit is provided between the filtration unit and the reaction unit. The dehumidification unit includes a hydrophobic ceramic filter element that is detachably installed inside the main body. The hydrophobic ceramic filter element is sealed and fitted to the inner wall of the main body. The surface of the hydrophobic ceramic filter element is provided with a hydrophobic modified coating. The hydrophobic ceramic filter element is used to reduce the relative humidity of the exhaust gas.

5. The low-temperature plasma synergistic catalytic tail gas purification device as described in claim 1, characterized in that, The catalytic unit is provided with a decomposition unit at its end. The decomposition unit includes an ozone catalytic carrier fixed in the main body. The ozone catalytic carrier is filled with an ozone decomposition catalyst, which is used to catalytically decompose the ozone byproducts generated by gaseous pollutants in the exhaust gas under the action of a high-voltage electric field into oxygen.

6. The low-temperature plasma synergistic catalytic tail gas purification device as described in claim 1, characterized in that, The manganese-copper-rare earth composite catalyst is a honeycomb ceramic supported catalyst.

7. The low-temperature plasma synergistic catalytic tail gas purification device as described in claim 1, characterized in that, The main body is connected to an intake connector and an exhaust connector at its intake and exhaust ends, respectively. The intake connector is sealed to the diesel engine exhaust pipe, and the exhaust connector directly discharges the purified exhaust gas into the atmosphere or connects to the subsequent exhaust pipe.

8. The low-temperature plasma synergistic catalytic tail gas purification device as described in claim 2, characterized in that, The body is provided with an integrated explosion-proof housing, which is a sealed explosion-proof structure, and the maximum operating temperature of the surface of the explosion-proof housing is ≤150℃.

9. The low-temperature plasma synergistic catalytic tail gas purification device as described in claim 8, characterized in that, A controller is installed on the outside of the explosion-proof housing. The controller has a built-in temperature and humidity sensor and an electrical parameter acquisition module. The detection end of the temperature and humidity sensor extends into the interior of the main body. The controller is electrically connected to the vehicle-mounted high-voltage pulse power supply, the temperature and humidity sensor, and the electrical parameter acquisition module.

10. A method for purifying exhaust gas using low-temperature plasma synergistic catalysis according to any one of claims 1-9, characterized in that, Includes the following steps: The exhaust gas emitted by the underground diesel vehicle enters the body and is filtered by the multi-layer filter to intercept large particles of dust and soot. After preliminary filtration, the exhaust gas enters the reaction unit. After the high-voltage electrode is energized, a high-voltage electric field is formed in the discharge gap between the high-voltage electrode and the grounding electrode. Under the action of the high-voltage electric field, high-energy electrons and active free radicals are generated to charge and break down the particulate matter in the filtered exhaust gas and to perform preliminary oxidation and activation of the gaseous pollutants in the exhaust gas. Particulate matter and gaseous pollutants in the exhaust gas after treatment in the reaction unit enter the catalytic unit. Under the action of manganese-copper-rare earth composite catalyst in the catalyst carrier, the nitrogen oxides that have been initially oxidized and activated are selectively catalytically reduced to nitrogen and water, and carbon monoxide and hydrocarbons are deeply oxidized to carbon dioxide and water. At the same time, the carbon soot particles that have been charged and crushed are deeply oxidized to carbon dioxide. The purified exhaust gas is finally discharged to the outside.

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