Ventilation air methane treatment system with multiple catalytic oxidation and carbon capture and method thereof
The waste gas methane treatment system, which utilizes multiple catalytic oxidation and carbon capture, employs gradient catalysis with copper-based, cobalt-based, and noble metal-based catalyst layers and a calcium oxide layer to capture carbon dioxide. This solves the problems of high catalyst costs and carbon cycle emissions, achieving economical and efficient reduction of waste gas methane emissions and greenhouse gas emissions.
Patent Information
- Application Number
- CN202511146268.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-15
- Publication Date
- 2025-11-14
AI Technical Summary
Existing catalytic oxidation technologies for reducing methane emissions from waste gas have problems such as high catalyst costs, susceptibility to poisoning, and end-of-carbon emissions, making it difficult to achieve cost-effective and efficient greenhouse gas emission reduction.
The waste methane treatment system employs multiple catalytic oxidation and carbon capture, which utilizes a stepwise synergistic catalysis of copper-based, cobalt-based and precious metal-based catalyst layers, combined with a calcium oxide layer to capture carbon dioxide, thereby reducing the amount of precious metals used and recovering carbon emissions.
While ensuring the catalytic oxidation effect, the amount of precious metal-based catalyst used was reduced, improving economic efficiency and effectively reducing carbon emissions, thus achieving greenhouse gas emission reduction.
Smart Images
Figure CN120939746A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to methane treatment, belonging to the field of air pollution and environmental protection emission reduction, specifically to a waste gas methane treatment system and method using multiple catalytic oxidation and carbon capture. Background Technology
[0002] During coal mining, when fresh air is continuously pumped into the mine to ensure underground air safety, the ventilation system emits exhaust gas containing extremely low concentrations of methane, known as exhaust methane. Although the concentration of exhaust methane is less than 0.75%, the overall emission volume is enormous, and it has gradually become one of the important sources of methane in the atmosphere. Methane is a potent greenhouse gas, and direct emission into the atmosphere will seriously harm the environment. Therefore, developing economical and efficient exhaust methane emission reduction technologies is of great significance for the coal industry to achieve its "dual carbon" goals and sustainable development. Catalytic oxidation technology is one of the most effective methods for reducing methane emissions from waste gas. It lowers the activation energy of the methane oxidation reaction through a catalyst, offering advantages such as low reaction temperature, high flexibility, and applicability to distributed energy systems. However, this technology is significantly affected by catalyst economics and activity cycles, limiting its applicability to large-scale applications. Furthermore, in methane catalytic oxidation, the catalyst is typically a precious metal-based catalyst, which is expensive and susceptible to poisoning by impurities such as sulfur and chlorine, requiring regular replacement and further increasing costs. In particular, to improve the economics of precious metal-based catalyst beds, composite catalysts are widely prepared by doping precious metals with transition metal elements. However, the recovery of these precious metals involves complex separation processes and high energy consumption, hindering their recycling. Moreover, while related technologies utilize catalysts to catalyze the oxidation of waste gas to reduce methane emissions, the direct release of the oxidation product, carbon dioxide, into the atmosphere exacerbates the end-of-pipe emissions problem in the carbon cycle. Summary of the Invention
[0003] The purpose of this invention is to provide a multi-stage catalytic oxidation and carbon capture system for treating exhaust methane, which achieves synergistic catalysis of exhaust methane at each stage. While ensuring the catalytic oxidation effect, it can reduce the amount of precious metal-based catalysts used, resulting in lower costs, and effectively reduce carbon emissions, thereby achieving greenhouse gas emission reduction.
[0004] To achieve the above objectives, a multi-stage catalytic oxidation and carbon capture system for treating exhaust gas methane includes: The reaction component includes a reactor, and a distribution plate, a foam ceramic layer, a catalyst layer, and a calcium oxide layer arranged sequentially from bottom to top inside the reactor. The catalyst layer comprises a copper-based catalyst layer, a cobalt-based catalyst layer, and a noble metal-based catalyst layer arranged from bottom to top. Exhausted methane at a certain temperature is introduced into the lower end of the reactor and discharged from the upper end.
[0005] In some examples of the present invention, the catalyst layer uses alumina particles as a carrier; The thicknesses of the copper-based catalyst layer, the cobalt-based catalyst layer, and the noble metal-based catalyst layer account for 40%-60%, 40%-60%, and 20%-40% of the catalyst layer, respectively.
[0006] In some examples of the present invention, the copper-based catalyst is one or more of copper oxide and copper acetate; the cobalt-based catalyst is one or more of cobalt oxide and cobalt tetroxide; and the noble metal-based catalyst is one or more of palladium and platinum.
[0007] In some examples of the present invention, a second heat exchanger is also included; The heat inlet pipe leading to the heat source is connected to the inlet of the second heat exchanger for heating exhaust methane. A first pipeline carrying exhaust methane is connected to a second heat exchanger, and the outlet of the second heat exchanger is connected to the lower end of the reactor via a second pipeline.
[0008] In some examples of the present invention, a first heat exchanger is also included; The inlet pipe for supplying exhaust methane is connected to the inlet of the first heat exchanger, and the upper end of the reactor is connected to the first heat exchanger through a third pipe for preheating the exhaust methane. The outlet of the first heat exchanger is connected to the first pipeline.
[0009] In some examples of the present invention, a first three-way valve is provided in the middle of the first pipeline; One port of the first three-way valve is connected to the inlet of the second heat exchanger via a fourth pipeline; The first three-way valve is controlled by a controller to open and close the connection between the outlet of the first heat exchanger and the inlet of the second heat exchanger, as well as between the outlet of the first heat exchanger and the bottom of the reactor.
[0010] In some examples of the present invention, a temperature sensor is provided on the first pipeline near the outlet of the first heat exchanger; The temperature sensor is connected to the controller, which controls the switching of the first three-way valve.
[0011] In some examples of the present invention, a second three-way valve is provided in the middle of the second pipeline; One port of the second three-way valve is connected to the first pipeline; The second three-way valve is controlled by a controller to open and close the outlet of the second heat exchanger and the bottom of the reactor, as well as the first pipeline and the bottom of the reactor.
[0012] The present invention also aims to provide a method for treating exhaust methane through multiple catalytic oxidation and carbon capture. Exhaust methane passes sequentially through a copper-based catalyst layer, a cobalt-based catalyst layer, and a noble metal-based catalyst layer to achieve synergistic catalysis of exhaust methane and reduce the amount of noble metal-based catalyst used. Furthermore, the calcium oxide layer is used to capture carbon dioxide generated from exhaust methane, which can effectively reduce carbon emissions and achieve greenhouse gas emission reduction.
[0013] A treatment method for exhaust gas methane using a multi-catalytic oxidation and carbon capture system specifically includes the following steps: S1, a heat source is introduced into the second heat exchanger to heat the exhaust methane that has not reached the required temperature; S2, heated exhaust methane enters from the bottom of the reactor and passes through a copper-based catalyst layer, a cobalt-based catalyst layer, and a noble metal-based catalyst layer in sequence, where it undergoes catalytic oxidation under the action of the corresponding catalyst layers; After the reaction, the high-temperature gas flow passes through the calcium oxide layer to capture carbon dioxide, is discharged, and then enters the first heat exchanger as a preheating source. S3, exhaust methane is introduced into the first heat exchanger for preheating, and a temperature sensor detects the temperature of the preheated exhaust methane. When the detected temperature reaches the set temperature, the preheated exhaust methane enters directly from the bottom of the reactor to proceed to step S2, while the heat source supplied to the second heat exchanger is turned off or reduced. When the detected temperature does not reach the set temperature, the heat source supplied to the second heat exchanger is turned on or increased. The preheated exhaust methane is first further heated through the second heat exchanger and then enters the reactor through the second pipeline to proceed to step S2.
[0014] Compared with existing technologies, this multi-stage catalytic oxidation and carbon capture waste gas methane treatment system features a catalyst layer consisting of a copper-based catalyst layer, a cobalt-based catalyst layer, and a noble metal-based catalyst layer arranged from bottom to top. These three catalysts work synergistically in a multi-gradient manner to catalyze waste gas methane, reducing the amount of noble metal-based catalyst used while ensuring the effectiveness of the catalytic oxidation reaction, thus improving the overall economic efficiency and lowering costs. Furthermore, the calcium oxide layer, located at the top, captures the carbon dioxide generated from the waste gas methane, effectively reducing carbon emissions and achieving greenhouse gas emission reduction. A first heat exchanger is installed on the upper part of the reactor... The first heat exchanger is connected to the second heat exchanger via a third pipeline to preheat the exhaust methane, thus achieving heat recovery and preheating of the exhaust methane. This reduces system heat loss, lowers system operating load, and improves exhaust methane processing capacity. In addition, by detecting the temperature of the exhaust methane, the system controls its connection to the reaction unit or the second heat exchanger, using the waste heat of the high-temperature gas flow to preheat the exhaust methane. Further heating via the second heat exchanger effectively reduces heat loss, lowers the frequency of dependence on external heating for this exhaust methane processing system, and thus reduces system energy consumption. Attached Figure Description
[0015] Figure 1 This is an overall schematic diagram of the present invention; Figure 2 This is a schematic diagram showing the connection between the second heat exchanger and the fourth and second pipelines in this invention; In the diagram: 11. Inlet pipe; 12. First pipe; 121. Pipe A; 122. Pipe B; 13. Second pipe; 131. Pipe C; 132. Pipe D; 14. Third pipe; 15. Fourth pipe; 16. Heat inlet pipe; 17. Heat outlet pipe; 18. Outlet pipe. 20. Conveyor; 31. First heat exchanger; 32. Second heat exchanger; 40. Temperature sensor; 50. Reaction component; 51. Air distribution plate; 52. Foam ceramic layer; 531. Copper-based catalyst layer; 532. Cobalt-based catalyst layer; 533. Noble metal-based catalyst layer; 54. Calcium oxide layer. 61. Intake valve; 62. Heat inlet valve; 71. First three-way valve; 72. Second three-way valve. Detailed Implementation
[0016] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. The same reference numerals in the drawings represent the same components. It should be noted that the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention.
[0017] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms “first,” “second,” and similar terms used in this patent application specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, “an” or “a” and similar terms do not necessarily indicate a quantity limitation. Terms such as “comprising” or “including” mean that the element or object preceding the word encompasses the element or object listed following the word and its equivalents, without excluding other elements or objects. Terms such as “connected” or “linked” are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as “upper,” “lower,” “left,” and “right” are used only to indicate relative positional relationships; these relative positional relationships may change accordingly when the absolute position of the described object changes.
[0018] like Figure 1 , Figure 2 As shown, this exhaust gas methane treatment system, which combines multiple catalytic oxidation and carbon capture, includes: The reaction component 50 includes a reactor, and a distribution plate 51, a foam ceramic layer 52, a catalyst layer, and a calcium oxide layer 54 arranged sequentially from bottom to top inside the reactor. The catalyst layer comprises a copper-based catalyst layer 531, a cobalt-based catalyst layer 532, and a noble metal-based catalyst layer 533 arranged from bottom to top. Exhaust methane at a certain temperature is introduced into the lower end of the reactor and discharged from the upper end; Specifically, in the reaction component 50, the reactor is a closed container structure, which can be equipped with corresponding opening and closing doors to facilitate the replacement of the corresponding catalytic oxidation layer; a valve is provided at the lower end of the reactor to regulate the amount of heated exhaust methane introduced; Exhaust methane can be heated to 550°C. The heated exhaust methane is then introduced into the reactor, passing from bottom to top through a distribution plate 51, a foam ceramic layer 52, a catalyst layer, and a calcium oxide layer 54. The distribution plate 51 ensures that the gas flow enters the reactor evenly and can support the upper catalyst layer. The foam ceramic layer 52, which can be made of silicon carbide foam ceramic, is positioned above the distribution plate 51 to prevent catalyst particles from clogging the distribution plate 51 and hindering the gas from entering the reactor. The catalyst layer includes a copper-based catalyst layer 531, a cobalt-based catalyst layer 532, and a noble metal-based catalyst layer 533. The three catalysts work together in a multi-gradient, stepwise synergistic manner to catalyze exhaust methane. While ensuring the catalytic oxidation reaction effect, the amount of noble metal-based catalyst used is reduced, the economy of the catalytic process is improved, and the overall cost is reduced. The calcium oxide layer 54 is located at the top and is used to capture the carbon dioxide produced by the catalytic oxidation of exhaust gas methane, thereby generating calcium carbonate and reducing the direct release of carbon dioxide, an oxidation product, into the air, which would exacerbate the end-of-cycle emissions problem of the carbon cycle.
[0019] In some examples of the present invention, the catalyst layer uses alumina particles as a carrier; The thicknesses of the copper-based catalyst layer 531, the cobalt-based catalyst layer 532, and the noble metal-based catalyst layer 533 account for 40%-60%, 40%-60%, and 20%-40% of the catalyst layer, respectively. Among them, the copper-based catalyst is one or more of copper oxide and copper acetate; the cobalt-based catalyst is one or more of cobalt oxide and cobalt tetroxide; and the noble metal-based catalyst is one or more of palladium and platinum.
[0020] Specifically, the catalyst layer adopts three different substrate catalytic forms. In particular, the thickness of the copper-based catalyst, cobalt-based catalyst, and noble metal-based catalyst is set. Without affecting the catalytic oxidation of exhaust methane, the thickness of the noble metal-based catalyst is limited, which can reduce the cost of using a single noble metal-based catalyst layer 533.
[0021] In some examples of the present invention, a waste methane treatment system involving multiple catalytic oxidation and carbon capture further includes: Second heat exchanger 32; The heat inlet pipe 16, which introduces the heat source, is connected to the inlet end of the second heat exchanger 32, and the first pipe 12, which carries exhaust methane, is connected to the second heat exchanger 32 for heating the exhaust methane. The outlet of the second heat exchanger 32 is connected to the lower end of the reactor via the second pipeline 13; Specifically, a heat inlet valve 62 may be installed on the heat inlet pipe 16. The heat inlet valve 62 is used to regulate the flow rate of the heat source. The second heat exchanger 32 is used to heat exhaust methane and can be heated by an external heat source, including but not limited to solar heating, electric heating, and gas supplementary heating. The other end of the second heat exchanger 32 can be connected to the heat outlet pipe 17. Exhaust methane is heated in the second heat exchanger 32 and then enters the reactor through the second pipe 13.
[0022] In some examples of the present invention, a waste methane treatment system involving multiple catalytic oxidation and carbon capture further includes: First heat exchanger 31; The inlet pipe 11 for introducing exhaust methane is connected to the inlet of the first heat exchanger 31, and the upper end of the reactor is connected to the first heat exchanger 31 through the third pipe 14 for preheating the exhaust methane. The outlet of the first heat exchanger 31 is connected to the first pipeline 12; Specifically, an intake valve 61 and a conveyor 20 can be installed on the intake pipe 11. Exhaust methane enters the first heat exchanger 31 from the intake pipe 11 and through the conveyor 20. The intake valve 61 is used to regulate the flow rate of exhaust methane, prevent the inlet pressure from being too high and overloaded, and at the same time ensure that emergency measures can be taken quickly in case of abnormal operation of the conveyor 20. The first heat exchanger 31 is used for heat recovery and preheating of exhaust methane, which can reduce system heat loss, reduce system operating load, and improve exhaust methane processing capacity. After being heated, the exhaust methane has a certain amount of heat after being discharged through the reaction assembly. This heat (residual heat) can be used to heat the exhaust methane through the first heat exchanger 31. The other end of the first heat exchanger 31 is connected to the gas outlet pipe 18 for exhaust treatment. That is, after being catalytically oxidized, the exhaust methane is discharged through the gas outlet pipe 18 connected to the first heat exchanger 31.
[0023] In some examples of the present invention, such as Figure 2 As shown, a first three-way valve 71 is provided in the middle of the first pipeline 12; One port of the first three-way valve 71 is connected to the inlet of the second heat exchanger 32 via the fourth pipe 15; The first three-way valve 71 is opened and closed by a controller to open and close the connection between the outlet of the first heat exchanger 31 and the inlet of the second heat exchanger 32, and between the outlet of the first heat exchanger 31 and the lower end of the reactor. Specifically, the first three-way valve 71 is installed on the first pipeline 12, which can be divided into pipeline A121 and pipeline B122. One end of pipeline A121 is connected to the outlet of the first heat exchanger 31, and the other end is connected to the first port of the first three-way valve 71. One end of pipeline B122 is connected to the second port of the first three-way valve 71, and the other end is connected to the second pipeline 13 or directly connected to the lower end of the reactor. The third port of the first three-way valve 71 is connected to the inlet of the second heat exchanger 32 through the fourth pipeline 15. Furthermore, a temperature sensor 40 is provided on the first pipeline 12 near the outlet of the first heat exchanger 31; Temperature sensor 40 is connected to the controller; Specifically, temperature sensor 40 is installed on pipeline A121, which can detect the temperature of the exhaust gas methane in real time and transmit the temperature signal to the controller wirelessly; the controller is the assembly of the control system, which can be a PLC controller. Initially, exhaust methane enters the first heat exchanger 31 from the inlet pipe 11 via the conveyor 20, and then enters the second heat exchanger 32 from the pipe A121 and the first three-way valve 71. A heat source is introduced into the second heat exchanger 32 to heat the exhaust methane. The heated exhaust methane enters the reaction unit 50 through the second pipeline 13 for catalytic oxidation treatment. The gas discharged from the top of the reaction unit 50 carries a certain amount of heat and is discharged through the first heat exchanger 31. The corresponding heat will preheat the exhaust methane in the first heat exchanger 31. The temperature sensor 40 detects the temperature of the preheated exhaust methane. When the temperature reaches the set temperature, the controller controls the opening between the outlet of the first heat exchanger 31 and the bottom of the reactor. That is, the first three-way valve 71 connects the pipeline A121 and the pipeline B122. The preheated exhaust methane can directly enter the reactor through the second pipeline 13. At this time, the controller closes or reduces the amount of heat source supplied to the second heat exchanger 32. When the temperature does not reach the set temperature, the controller controls the opening between the outlet of the first heat exchanger 31 and the inlet of the second heat exchanger 32, that is, the first three-way valve 71 connects the pipeline A121 and the fourth pipeline 15, and the preheated exhaust methane first passes through the second heat exchanger 32 for further heating, and then enters the reactor through the second pipeline 13. This example controls the inflow of exhaust methane into the reaction unit 50 or the second heat exchanger 32 by detecting the temperature of the exhaust methane. The exhaust methane is preheated by the waste heat of the high-temperature gas flow and further heated by the second heat exchanger 32. This effectively reduces heat loss, lowers the frequency of dependence of the exhaust methane treatment system on external heating, and thus reduces system energy consumption.
[0024] In some examples of the present invention, a second three-way valve 72 is provided in the middle of the second pipeline 13; One port of the second three-way valve 72 is connected to the first pipeline 12; The second three-way valve 72 is opened and closed by the controller, opening and closing the outlet of the second heat exchanger 32 and the lower end of the reactor, as well as the connection between the first pipeline 12 and the lower end of the reactor. Specifically, the second three-way valve 72 is installed on the second pipeline 13, which can be divided into pipeline C131 and pipeline D132. One end of pipeline C131 is connected to the outlet of the second heat exchanger 32 and the other end is connected to the first port of the second three-way valve 72. One end of pipeline D132 is connected to the second port of the second three-way valve 72 and the other end is directly connected to the lower end of the reactor. Pipeline B122 is connected to the third port of the second three-way valve 72. When the temperature reaches the set temperature, pipe A121 is connected to pipe 15 through the first three-way valve 71, pipe C131 is connected to pipe D132 through the second three-way valve 72, and pipe B122 is in a closed state; when the temperature reaches the set temperature, pipe A121 is connected to pipe B122 through the first three-way valve 71, pipe B122 is connected to pipe D132 through the second three-way valve 72, and the area between pipe 15 and pipe C131 is in a closed state; the first three-way valve 71 and the second three-way valve 72 can facilitate the opening and closing of the corresponding passages, realize the smooth flow of air at different temperatures, and effectively prevent the airflow from flowing back into pipe B122 or pipe C131.
[0025] When using this multi-catalytic oxidation and carbon capture waste gas methane treatment system, the specific steps include: S1, a heat source is introduced into the second heat exchanger 32 to heat the exhaust methane that has not reached the required temperature; S2, heated exhaust methane enters from the bottom of the reactor and passes sequentially through copper-based catalyst layer 531, cobalt-based catalyst layer 532 and noble metal-based catalyst layer 533, where it undergoes catalytic oxidation under the action of the corresponding catalyst layers; After the reaction, the high-temperature gas flow passes through the calcium oxide layer 54 to capture carbon dioxide, and after being discharged, it enters the first heat exchanger 31 as a preheating source. S3, exhaust methane is introduced into the first heat exchanger 31 for preheating, and temperature sensor 40 detects the temperature of the preheated exhaust methane. When the detected temperature reaches the set temperature, the preheated exhaust methane enters directly from the bottom of the reactor to proceed to step S2, while the heat source supplied to the second heat exchanger 32 is turned off or reduced. When the detected temperature does not reach the set temperature, the heat source supplied to the second heat exchanger 32 is turned on or increased. The preheated exhaust methane is first further heated through the second heat exchanger 32, and then enters the reactor through the second pipeline 13 to proceed to step S2.
[0026] The foregoing description, with reference to preferred embodiments, details an exemplary embodiment of the exhaust gas methane treatment system proposed in this invention, which involves multiple catalytic oxidation and carbon capture. However, those skilled in the art will understand that various modifications and alterations can be made to the above specific embodiments without departing from the concept of this invention, and various combinations can be made to the various technical features and structures proposed in this invention, without exceeding the protection scope of this invention, which is determined by the appended claims.
Claims
1. A waste methane treatment system involving multiple catalytic oxidation and carbon capture, characterized in that, include: The reaction component (50) includes a reactor, and a distribution plate (51), a foam ceramic layer (52), a catalyst layer, and a calcium oxide layer (54) arranged sequentially from bottom to top inside the reactor. The catalyst layer comprises a copper-based catalyst layer (531), a cobalt-based catalyst layer (532), and a noble metal-based catalyst layer (533) arranged from bottom to top. Exhausted methane at a certain temperature is introduced into the lower end of the reactor and discharged from the upper end.
2. The waste gas methane treatment system based on multiple catalytic oxidation and carbon capture according to claim 1, characterized in that, The catalyst layer uses alumina particles as a carrier; The thicknesses of the copper-based catalyst layer (531), the cobalt-based catalyst layer (532), and the noble metal-based catalyst layer (533) account for 40%-60%, 40%-60%, and 20%-40% of the catalyst layer, respectively.
3. The waste gas methane treatment system based on multiple catalytic oxidation and carbon capture according to claim 1, characterized in that, The copper-based catalyst is one or more of copper oxide and copper acetate; the cobalt-based catalyst is one or more of cobalt oxide and cobalt tetroxide; and the noble metal-based catalyst is one or more of palladium and platinum.
4. A waste gas methane treatment system based on multiple catalytic oxidation and carbon capture according to any one of claims 1 to 3, characterized in that, It also includes: a second heat exchanger (32); The heat inlet pipe (16) leading to the heat source is connected to the inlet of the second heat exchanger (32) for heating exhaust methane; A first pipeline (12) through which exhaust methane is supplied is connected to a second heat exchanger (32), and the outlet of the second heat exchanger (32) is connected to the lower end of the reactor through a second pipeline (13).
5. The waste gas methane treatment system based on multiple catalytic oxidation and carbon capture according to claim 4, characterized in that, It also includes: the first heat exchanger (31); The gas inlet pipe (11) for supplying exhaust methane is connected to the inlet of the first heat exchanger (31), and the upper end of the reactor is connected to the first heat exchanger (31) through the third pipe (14) for preheating the exhaust methane. The outlet of the first heat exchanger (31) is connected to the first pipeline (12).
6. The waste gas methane treatment system based on multiple catalytic oxidation and carbon capture according to claim 5, characterized in that, The first three-way valve (71) is provided in the middle of the first pipeline (12); One port of the first three-way valve (71) is connected to the inlet of the second heat exchanger (32) via the fourth pipe (15); The first three-way valve (71) is opened and closed by a controller to open and close the connection between the outlet of the first heat exchanger (31) and the inlet of the second heat exchanger (32), and to open and close the connection between the outlet of the first heat exchanger (31) and the bottom of the reactor.
7. The waste gas methane treatment system based on multiple catalytic oxidation and carbon capture according to claim 6, characterized in that, A temperature sensor (40) is provided on the first pipeline (12) near the outlet of the first heat exchanger (31). The temperature sensor (40) is connected to the controller, which controls the switching of the first three-way valve (71).
8. The waste gas methane treatment system based on multiple catalytic oxidation and carbon capture according to claim 7, characterized in that, The second pipeline (13) is equipped with a second three-way valve (72) in the middle. One port of the second three-way valve (72) is connected to the first pipeline (12); The second three-way valve (72) is opened and closed by the controller, opening and closing the outlet of the second heat exchanger (32) and the lower end of the reactor, as well as the first pipeline (12) and the lower end of the reactor.
9. A treatment method for exhaust gas methane from a multi-catalytic oxidation and carbon capture system as described in claim 7, characterized in that, Specifically, the following steps are included: S1, a heat source is introduced into the second heat exchanger (32) to heat the exhaust methane that has not reached the required temperature; S2, heated exhaust methane enters from the bottom of the reactor and passes through the copper-based catalyst layer (531), the cobalt-based catalyst layer (532), and the noble metal-based catalyst layer (533) in sequence, where it undergoes catalytic oxidation under the action of the corresponding catalyst layers; After the reaction, the high-temperature gas flow passes through the calcium oxide layer (54) to capture carbon dioxide, is discharged, and then enters the first heat exchanger (31) as a preheating source. S3, exhaust methane is introduced into the first heat exchanger (31) for preheating, and temperature sensor (40) detects the temperature of the preheated exhaust methane; When the detected temperature reaches the set temperature, the preheated exhaust methane enters directly from the bottom of the reactor to proceed to step S2, while the heat source supplied to the second heat exchanger (32) is turned off or reduced. When the detected temperature does not reach the set temperature, the heat source entering the second heat exchanger (32) is turned on or increased. The preheated exhaust methane is first further heated through the second heat exchanger (32) and then enters the reactor through the second pipeline (13) to carry out step S2.