A coal mine exhaust gas low concentration methane oxidation removal system

Abstract

The present invention relates to a low-concentration methane oxidation removal system for coal mine exhaust gas, comprising: an induced draft dust removal device, a methane oxidation reactor, a carbon capture reactor, a calcium-based adsorbent feeder and a heat exchanger; the induced draft dust removal device is connected to the methane oxidation reactor through an air duct, and the mine gas is initially dust-filtered and continuously transported to the inside of the methane oxidation reactor, the methane oxidation reactor is connected to the carbon capture reactor through an air duct, the carbon capture reactor is also connected to the calcium-based adsorbent feeder (which can realize continuous feeding and post-reaction absorbent recovery, and keep the bed layer with a sufficient amount of calcium-based absorbent for carbon capture reaction), and the methane oxidation reactor is also connected to the heat exchanger through the air duct. The beneficial effects of the present invention are: compared with existing equipment, the present invention can significantly improve energy utilization, reduce energy consumption and fully utilize materials, and at the same time has the characteristics of compact structure and strong applicability.

Description

Technical Field

[0001] The present invention belongs to the technical field related to energy utilization equipment, and in particular relates to a low-concentration methane oxidation removal system for coal mine exhaust gas based on catalytic oxidation and carbon capture technology. Background Art

[0002] Underground mining is the main means of coal production in my country. The coal mine gas (coalbed methane) released during the mining process can easily lead to gas accidents, posing a great safety hazard to the coal mine production process.

[0003] The relevant regulations divide underground coal mine gas emissions into extraction gas and wind exhaust gas. The methane concentration of extraction gas is generally higher than 30%, and the methane concentration of pre-extraction gas can reach more than 90%. Low-concentration extraction gas can also be purified by pressure swing adsorption and other technical means for use, mainly for civil gas, gas power generation and other industrial purposes. However, the concentration of wind exhaust gas discharged by ventilation is generally less than 0.5%, which makes it difficult to effectively utilize it, and it is impossible to reduce emissions in order to ensure coal mine safety.

[0004] The Coal Mine Safety Regulations stipulate that in order to ensure the safety of coal mine production, the methane concentration at the ventilation well of gas-producing coal mines must be lower than 0.75%. According to relevant regulations, by 2007, the amount of gas discharged by key state-owned coal mines exceeded 6 billion cubic meters. Due to its low methane concentration, it is currently mainly directly discharged into the atmosphere, causing relatively large greenhouse gas pollution.

[0005] It can be seen that in the process of coal mining in my country, a large amount of gas is directly discharged into the atmosphere without being treated. The greenhouse effect of methane is about CO 2 28 times, with the current society paying more and more attention to environmental protection, the control of coal mine gas emissions has become increasingly important. At the same time, the world is striving to promote carbon neutrality, and the non-CO 2 The carbon capture process is also a very important area.

[0006] To analyze more specifically, the existing technology does not effectively control greenhouse gas emissions from coal mine exhaust gas with methane concentration below 0.75%. As the society's demand for environmental protection gradually increases, how to cleanly and efficiently achieve coal mine exhaust gas emission control requirements and specifically design its supporting component systems and working methods is becoming a technical problem that needs to be urgently solved in this field. Summary of the invention

[0007] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a system for removing low-concentration methane from coal mine exhaust gas through oxidation.

[0008] The low-concentration methane oxidation removal system of coal mine exhaust gas comprises: an induced draft dust removal device 1, a methane oxidation reactor 2, a carbon capture reactor 3, a calcium-based adsorbent feeder 4 and a heat exchanger 5; the induced draft dust removal device 1 is connected to the methane oxidation reactor 2 through an air duct, and the mine gas is initially dust-removed and filtered before being continuously transported to the inside of the methane oxidation reactor 2; the methane oxidation reactor 2 is connected to the carbon capture reactor 3 through an air duct, and the carbon capture reactor 3 is also connected to the calcium-based adsorbent feeder 4 (which can realize continuous feeding and post-reaction absorbent recovery, and keep a sufficient amount of calcium-based absorbent in the bed for carbon capture reaction), and the methane oxidation reactor 2 is also connected to the heat exchanger 5 through an air duct; the catalyst is filled in the methane oxidation reactor 2, and the calcium-based absorbent is filled in the carbon capture reactor 3.

[0009] Preferably, an induction heating device is provided on the catalyst bed, and induction heating is used for heating and energy supply; the reaction temperature range of the catalyst is 300-450°C. When the catalyst is preheated to the first specified temperature (400°C) by high-frequency induction heating, the gas input from the outside contacts the catalyst and undergoes a methane oxidation reaction, and the methane in the gas reacts to generate H 2 O and CO 2 The product gas after the reaction continues to enter the carbon capture reactor 3 to carry out the carbon capture reaction process.

[0010] Preferably, the catalyst is a honeycomb ceramic supported catalyst, the pore size of which is adjustable and the flow resistance is controllable.

[0011] Preferably, the components of the honeycomb ceramic loaded catalyst are nano copper oxide, 316 stainless steel particles and cordierite honeycomb ceramic; wherein the mass percentage of nano copper oxide is 10% to 20%, the mass percentage of 316 stainless steel particles is 10 to 30%, and the mass percentage of cordierite honeycomb ceramic is 50 to 80%; nano copper oxide serves as an oxidation reaction catalyst, 316 stainless steel particles serve as a heating body, and cordierite honeycomb ceramic serves as a carrier material.

[0012] Preferably, the components of the honeycomb ceramic supported catalyst are 15% of nano copper oxide, 30% of 316 stainless steel particles and 55% of cordierite honeycomb ceramic, and the above percentages are all by mass.

[0013] Preferably, the reaction temperature of the calcium-based absorbent is in the range of 80 to 200°C. When the carbon capture reactor 3 reaches the second specified temperature (120°C), the carbon capture reactor 3 reacts with the CO2-containing gas output from the methane oxidation reactor 2. 2 Gas contact reaction can effectively absorb CO 2 The product gas after the reaction in the methane oxidation reactor 2 passes through the heat exchanger 5 to cool the product gas. At the same time, the heat exchanger 5 transfers heat to the inlet of the methane oxidation reactor 2 to preheat the intake air, thereby achieving an energy-saving effect.

[0014] The method for constructing the low-concentration methane oxidation removal system of coal mine exhaust gas specifically comprises the following steps:

[0015] Step 1, preparing a catalyst;

[0016] Step 1.1, first prepare Cu(NO 3 ) 2 solution, ammonia and NaOH solution; then, under set temperature and stirring conditions, Cu(NO 3 ) 2 Slowly drop ammonia water into the solution; then drop the prepared NaOH solution into the obtained mixed solution until the pH value of the mixed solution is 9-10, to obtain a blue suspended precursor solution; finally, perform multiple centrifugal precipitations, remove the supernatant after each centrifugation, and add deionized water according to the same volume as the removed supernatant;

[0017] Step 1.2, taking the blue suspension precursor solution obtained in step 1.1, obtaining a blue precipitation slurry by centrifugal precipitation; transferring the blue precipitation slurry into a reactor, heating it to a set temperature at a certain heating rate and keeping it warm; after the blue precipitation slurry in the reactor is cooled, centrifuging and drying the generated black slurry to obtain a black powder, which is a nano copper oxide catalyst;

[0018] Step 1.3, putting 316 stainless steel particles into a polyethylene glycol solution, and immersing the cordierite honeycomb ceramic in the polyethylene glycol solution with the stainless steel particles for a period of time under stirring, taking out the cordierite honeycomb ceramic, drying it, and then performing high-temperature calcination treatment in batches;

[0019] Step 1.4, mixing the black powder prepared in step 1.2 with anhydrous ethanol, and placing the cordierite honeycomb ceramic prepared in step 1.3 into the mixed solution of the black powder and anhydrous ethanol under stirring for immersion treatment, and then drying again to obtain a catalyst (the desired oxygen carrier product);

[0020] Step 2, preparing a calcium-based absorbent, wherein the calcium-based absorbent is calcium oxide;

[0021] Step 2.1, take Ca(OH) 2 The powder is mixed with a polyethylene glycol aqueous solution at room temperature to form a viscous mass, which is then placed in an extruder to extrude the viscous mass to form a strip-shaped precursor product;

[0022] Step 2.2, placing the strip precursor extruded in step 2.1 into a spheronizer, and rotating the spheronizer to form a granular product under the action of force;

[0023] Step 2.3: drying the granular product formed in step 2.2, and then calcining it to obtain a calcium-based absorbent.

[0024] Preferably, in step 1.1, Cu(NO 3 ) 2 The molar concentrations of solution, ammonia water and NaOH solution were 0.5mmol / L, 0.15mol / L and 1mol / L respectively; the set temperature was 50℃, and the ammonia water and Cu(NO 3 ) 2 The volume ratio of the solution is controlled to be 3:10; the number of centrifugal separations is 5 times; the centrifugal speed when the blue suspended precursor solution is centrifuged in step 1.2 is 8000 rpm, and the centrifugal time is 5 minutes each time; the heating rate of the blue precipitate slurry in the reactor is 5°C / min, the set temperature is 130°C, and the insulation time is 10 hours; the centrifugal speed when the black slurry generated after the blue precipitate slurry in the reactor is cooled is 10000 rpm, and the centrifugal time is 10 minutes each time; the black slurry is dried The time is 24 hours, and the drying temperature is 80°C; the stainless steel particles in step 1.3 are 200-300 meshes; the concentration of the polyethylene glycol solution is 1 mol / L; the immersion time of the cordierite honeycomb ceramics in the polyethylene glycol solution with stainless steel particles is 2 hours; the drying temperature of the impregnated cordierite honeycomb ceramics is 105°C-130°C, and the drying time is 12 hours; the temperature of the high-temperature calcination treatment is 400°C, and the calcination time is 3 hours; in step 1.4, the concentration of the black powder in the mixed solution of the cordierite honeycomb ceramics and anhydrous ethanol is 0.1-0.3 mol / L.

[0025] Preferably, in step 2.1, the concentration of polyethylene glycol in the polyethylene glycol aqueous solution is 1-2 mol / L, and the diameter of the strip precursor product is 2-3 mm; in step 2.2, the rotation speed of the spheronizer is 60 rpm, and the rotation time is 60 min; the diameter of the granular product is 2-3 mm; in step 2.3, the drying time is 24 h, and the drying temperature is 80-105 ° C; the calcination temperature is 700 ° C, and the calcination time is 3 h.

[0026] The beneficial effects of the present invention are:

[0027] The present invention studies and designs the key component modules of the low-concentration methane oxidation removal system of coal mine exhaust gas and its specific configuration, especially the working mode of the methane oxidation catalyst and the oxidation removal / carbon capture process. Compared with the existing equipment, it can significantly improve the energy utilization rate, reduce energy consumption and fully utilize materials, and at the same time has the characteristics of compact structure and strong applicability.

[0028] The present invention studies and designs the types of key catalysts and key process conditions of the reaction route. Compared with the existing preparation process, it can not only achieve a highly selective and highly reactive methane oxidation reaction, but also effectively improve the response speed and energy utilization rate.

[0029] The process for preparing the catalyst of the present invention is easy to control, has a high reaction rate and excellent product performance, and can obtain a methane oxidation reaction conversion rate of more than 99% under reaction conditions below 400°C. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic diagram of the overall structure of the coal mine gas low-concentration methane oxidation removal system;

[0031] Figure 2 A schematic diagram of a process flow for preparing a honeycomb ceramic catalyst;

[0032] Figure 3 Schematic diagram of the process flow for preparing calcium-based absorbent.

[0033] Explanation of reference numerals: induced draft dust removal device 1 , methane oxidation reactor 2 , carbon capture reactor 3 , calcium-based adsorbent feeder 4 , heat exchanger 5 . DETAILED DESCRIPTION

[0034] The present invention is further described below in conjunction with embodiments. The description of the following embodiments is only used to help understand the present invention. It should be noted that for ordinary persons in the art, without departing from the principle of the present invention, the present invention can also be modified in some ways, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

[0035] The present invention uses a methane oxidation reactor to oxidize methane into carbon dioxide and water at low temperature, and captures and collects carbon dioxide through a carbon capture reactor. The heat required in the methane oxidation reaction is used to supply energy to the oxidation reaction catalyst through induction heating. The gas after the reaction is passed into the carbon capture reactor to capture the generated carbon dioxide, and the calcium adsorbent feeder continuously updates the calcium adsorbent in the carbon capture reactor. The present invention also carries out targeted design of the catalyst and carbon dioxide adsorbent used in the above system. The present invention can realize the oxidation removal and carbon capture process of low-concentration methane in gas at low cost, high energy utilization rate, and environmentally friendly under the conditions of low energy consumption, rapid startup, and high dynamic response. The equipment is compact and the operation is flexible and convenient.

[0036] Embodiment 1:

[0037] The overall structure diagram of a coal mine exhaust gas low concentration methane oxidation removal system is as follows Figure 1As shown in Figure 2, the process of low-concentration methane oxidation removal mainly realizes the production of CO from methane through the methane oxidation reaction on the catalyst surface. 2 and H 2 O, while passing through with CO 2 After the reaction, the gas reacts with the calcium absorbent to remove CO 2 The reaction is captured and retained in the calcium carbonate product. The reaction process is as follows:

[0038] Methane oxidation reactor: CH 4 +2O 2 →CO 2 +2H 2 O

[0039] Carbon capture reactor: CO 2 +CaO→CaCO 3

[0040] On the methane oxidation catalyst designed in this embodiment, the reaction activity and reaction conversion rate of the methane oxidation reaction are both high, and the preparation cost of the catalyst is also relatively low. At the same time, in order to improve the response speed and reduce the energy consumption of the heating process, the device used in this embodiment selects induction heating as the heating method of the methane oxidation reactor. At the same time, in order to further reduce energy consumption, a heat exchanger is set at the end of the methane oxidation reactor to preheat the intake air using the discharged high-temperature product gas.

[0041] Closely combining the above characteristics and specific working conditions, this embodiment specifically proposes a low-concentration methane oxidation removal system for coal mine exhaust gas, which not only realizes low-energy consumption and high-response speed methane oxidation reaction through the design of methane oxidation catalyst, but also realizes CO through carbon capture reactor. 2 This device can realize stable, low energy consumption and high efficiency methane oxidation removal process under low cost and compact equipment conditions. Figure 1 As shown, the system includes functional components such as an induced draft dust removal device 1, a methane oxidation reactor 2, a carbon capture reactor 3, a calcium-based adsorbent feeder 4 and a heat exchanger 5, which will be explained one by one below.

[0042] The induced draft dust removal device 1 is connected to the methane oxidation reactor 2. The induced draft dust removal device 1 filters and removes dust from the exhaust gas, and then sends it into the methane oxidation reactor 2 to undergo oxidation reaction with the catalyst.

[0043] The methane oxidation reactor 2 is filled with a methane oxidation catalyst. When the methane oxidation reactor is heated to a first specified temperature under the condition of induction heating, the exhaust gas introduced by the induced draft dust removal device 1 undergoes a methane oxidation reaction on the catalyst surface to generate a gas containing H 2 O and CO 2The generated gas is cooled by the heat exchanger 5 at the end of the methane oxidation reactor 2, and the heat exchanger 5 sends heat back to the inlet of the methane oxidation reactor 2 to preheat the intake gas.

[0044] CO generated by methane oxidation reactor 2 2 The gas enters the carbon capture reactor 3, CO 2 The carbon dioxide reacts with the calcium adsorbent in the carbon capture reactor 3 and is captured in the calcium adsorbent. At the same time, the gas stream after methane oxidation removal and carbon capture can be discharged into the atmosphere.

[0045] The calcium-based absorbent feeder 4 is connected to the carbon capture reactor 3. During the carbon capture process, the calcium-based absorbent feeder 4 performs continuous feeding and post-reaction absorbent recovery to maintain a sufficient amount of calcium-based absorbent in the bed of the carbon capture reactor 3 for carbon capture reaction.

[0046] This embodiment couples the methane oxidation reaction and the carbon capture process, realizes a low-energy oxidation reaction by induction heating, and performs carbon capture by applying a calcium-based absorbent. It can not only give full play to the high performance of the nano-copper-based methane oxidation catalyst, but also realize low-cost carbon dioxide capture, and overall considers the optimal configuration of energy utilization, energy consumption and material utilization.

[0047] The above-mentioned methane oxidation catalyst comprises nano-belt CuO, 316 stainless steel particles and cordierite honeycomb ceramics, and the mass percentages of the three are 10% to 20% for nano-copper oxide, 10% to 30% for stainless steel particles, and 50% to 80% for cordierite honeycomb ceramic carriers; wherein the nano-copper oxide serves as an oxidation reaction catalyst, the stainless steel particles serve as a heating body, and the cordierite honeycomb ceramics serve as a carrier material.

[0048] Embodiment 2:

[0049] like Figure 2 As shown, the preparation process of the catalyst in Example 1 comprises the following steps:

[0050] First, configure Cu(NO 3 ) 2 The molar concentrations of solution, ammonia solution and NaOH solution were 0.5mmol / L, 0.15mol / L and 1mol / L respectively, and then Cu(NO 3 ) 2 Ammonia water is slowly added to the solution. Ammonia water and Cu(NO 3 ) 2The volume ratio of the solution was controlled at 3:10, and then NaOH solution was added dropwise to the mixed solution until the pH value of the mixed solution reached 9-10, thereby obtaining a blue suspended precursor solution. Finally, five centrifugal precipitations were performed, with a centrifugal speed of 8000 rpm and a centrifugal time of 5 min. After each centrifugation, the supernatant was removed and deionized water was added at the same volume.

[0051] Next, take the blue suspension precursor solution, obtain the blue precipitation slurry by centrifugal precipitation, transfer it into the reactor, heat it to 130 degrees Celsius at a rate of 5°C / min and keep it warm for 10 hours. After cooling, centrifuge the generated black slurry at a centrifugal speed of 10000rpm for 10 minutes, and dry it at 80°C for 24 hours. The obtained black powder is the nano copper oxide catalyst.

[0052] Next, 200-300 mesh 316 stainless steel particles were placed in a 1 mol / L polyethylene glycol solution, and the cordierite honeycomb ceramics were immersed in the solution for 2 hours under stirring. After being taken out, the honeycomb ceramics were dried and aged at a temperature of 105°C to 130°C for 12 hours, and then subjected to high-temperature calcination treatment in batches, with a calcination temperature of 400°C and a calcination time of 3 hours.

[0053] Next, the black catalyst powder is mixed with anhydrous ethanol at a concentration of 0.1-0.3 mol / L to form a catalyst slurry, and the prepared honeycomb ceramic is placed in the slurry for impregnation treatment under stirring, and then dried again to obtain the desired oxygen carrier product.

[0054] Through the above ideas, on the one hand, the methane oxidation removal reaction is realized by using nano copper oxide as the catalyst core, and the 316 stainless steel particles are mainly used in the induction heating process to heat the catalyst with a high response speed, while the honeycomb ceramic is used as a carrier material to support the catalyst and stainless steel particles. The honeycomb ceramic catalyst can realize a low-cost, high-energy utilization, and environmentally friendly methane oxidation reaction process under the conditions of low energy consumption, fast startup, and high dynamic response, and the preparation process is simple and easy to realize industrialization.

[0055] like Figure 3 As shown, the preparation process of the carbon capture absorbent (calcium-based absorbent) in Example 1 is designed; the preparation process specifically includes the following steps:

[0056] (a) Take Ca(OH) 2 The powder is mixed with a polyethylene glycol aqueous solution (polyethylene glycol concentration is 1-2 mol / L) at room temperature to form a viscous mass, which is then put into an extruder and extruded to form a strip-shaped precursor product with a diameter of about 2-3 mm.

[0057] (b) The precursor extruded in step (a) is placed in a spheronizer, the rotation speed is controlled at 60 rpm, and the rotation time is 60 min. Through the rotation process, the strip precursor is formed into a granular product of about 2 to 3 mm under the action of force.

[0058] (c) The granular product formed in step (b) is dried at a temperature of 80-105° C. for 24 hours, and then calcined at a temperature of 700° C. for 3 hours to obtain the desired calcium-based absorbent.

[0059] Embodiment 3:

[0060] The specific working process of the methane oxidation removal system is:

[0061] When the system is started, the methane oxidation reactor heats the catalyst through induction heating. When the predetermined temperature is reached, the induced draft dust removal device draws in the exhaust gas and removes the dust, and then passes it into the methane oxidation reactor.

[0062] When the temperature of the methane oxidation reactor is raised to, for example, 400°C by induction heating, the exhaust gas from the induced draft dust removal device is introduced and methane oxidation reaction occurs to generate CO 2 and H 2 At a reaction temperature of 400°C, methane can be converted to nearly 100%. At the same time, the gas after the reaction is cooled by a heat exchanger, and the heat exchanger heats the intake air to reduce energy consumption.

[0063] The product gas in the methane oxidation reactor is passed into the carbon capture reactor to react with the calcium adsorbent. 2 Captured by calcium adsorbent.

[0064] The calcium-based absorbent feeder is connected to the carbon capture reactor. During the carbon capture process, the calcium-based absorbent feeder performs continuous feeding and post-reaction absorbent recovery to maintain a sufficient amount of calcium-based absorbent in the bed of the carbon capture reactor for carbon capture reaction.

Claims

1. A method for constructing a low-concentration methane oxidation removal system for coal mine exhaust gas, characterized in that: include: An induced draft dust removal device (1), a methane oxidation reactor (2), a carbon capture reactor (3), a calcium-based adsorbent feeder (4) and a heat exchanger (5); the induced draft dust removal device (1) is connected to the methane oxidation reactor (2) via an air duct, the methane oxidation reactor (2) is connected to the carbon capture reactor (3) via an air duct, the carbon capture reactor (3) is also connected to the calcium-based adsorbent feeder (4), and the methane oxidation reactor (2) is also connected to the heat exchanger (5) via an air duct; the methane oxidation reactor (2) is filled with a catalyst, and the carbon capture reactor (3) is filled with a calcium-based adsorbent; an induction heating device is provided on the catalyst bed; the reaction temperature range of the catalyst is 300 to 450° C. The catalyst preparation method is as follows: Step 1.1, first prepare Cu(NO3)2 solution, ammonia water and NaOH solution; then slowly add ammonia water to the Cu(NO3)2 solution under set temperature and stirring conditions; then add the prepared NaOH solution to the obtained mixed solution until the pH value of the mixed solution is 9-10, to obtain a blue suspended precursor solution; Finally, multiple centrifugation precipitations were performed, and after each centrifugation, the supernatant was removed and the volume of deionized water was supplemented according to the same volume as the removed supernatant; Step 1.2, taking the blue suspended precursor solution obtained in step 1.1, and obtaining a blue precipitation slurry by centrifugal precipitation; transferring the blue precipitation slurry into a reaction kettle, heating it to a set temperature at a certain heating rate and keeping it warm; After the blue precipitate slurry in the reactor is cooled, the generated black slurry is centrifuged and dried to obtain a black powder, which is a nano copper oxide catalyst; Step 1.3, putting stainless steel particles into a polyethylene glycol solution, and immersing the cordierite honeycomb ceramic in the polyethylene glycol solution with stainless steel particles for a period of time under stirring, taking out the cordierite honeycomb ceramic, drying it, and then performing high-temperature calcination treatment in batches; Step 1.4, mixing the black powder prepared in step 1.2 with anhydrous ethanol, and placing the cordierite honeycomb ceramic prepared in step 1.3 into the mixed solution of the black powder and anhydrous ethanol under stirring for immersion treatment, and then drying again to obtain a catalyst; Prepare a calcium-based absorbent, wherein the calcium-based absorbent is calcium oxide, and the preparation method is as follows: Step 2.1, mixing Ca(OH)2 powder with a polyethylene glycol aqueous solution at room temperature to form a viscous mass, then putting the viscous mass into an extruder to extrude the viscous mass to form a strip-shaped precursor product; Step 2.2, placing the strip precursor extruded in step 2.1 into a spheronizer, and rotating the spheronizer to form a granular product under the action of force; Step 2.3: drying the granular product formed in step 2.2, and then calcining it to obtain a calcium-based absorbent.

2. The method for constructing a low-concentration methane oxidation removal system for coal mine exhaust gas according to claim 1, characterized in that: In step 1.1, the molar concentrations of the Cu(NO3)2 solution, ammonia water and NaOH solution are 0.5 mmol / L, 0.15 mol / L and 1 mol / L respectively; the temperature is set at 50°C, the volume ratio of ammonia water to Cu(NO3)2 solution is controlled to be 3:10; the number of centrifugal separations is 5 times; In step 1.2, the centrifugal speed of the blue suspended precursor solution during centrifugation is 8000 rpm, and the centrifugal time is 5 min each time; the heating rate of the blue precipitate slurry in the reactor is 5°C / min, the set temperature is 130°C, and the insulation time is 10 h; the centrifugal speed of the black slurry generated after the blue precipitate slurry in the reactor is cooled and centrifuged is 10000 rpm, and the centrifugal time is 10 min each time; the drying time of the black slurry is 24 h, and the drying temperature is 80°C; In step 1.3, the stainless steel particles are 200-300 meshes; the concentration of the polyethylene glycol solution is 1 mol / L; the cordierite honeycomb ceramic is immersed in the polyethylene glycol solution with stainless steel particles for 2 hours; the drying temperature of the impregnated cordierite honeycomb ceramic is 105°C-130°C, and the drying time is 12 hours; the temperature of the high temperature calcination treatment is 400°C, and the calcination time is 3 hours; In step 1.4, the concentration of the black powder in the mixed solution of the black powder and anhydrous ethanol is 0.1-0.3 mol / L.

3. The method for constructing a low-concentration methane oxidation removal system for coal mine exhaust gas according to claim 1, characterized in that: In step 2.1, the concentration of polyethylene glycol in the polyethylene glycol aqueous solution is 1-2 mol / L, and the diameter of the strip precursor product is 2-3 mm; In step 2.2, the rotation speed of the spheronizer is 60 rpm, and the rotation time is 60 min; the diameter of the granular product is 2 to 3 mm; In step 2.3, the drying time is 24 hours, and the drying temperature is 80-105° C.; the calcination temperature is 700° C., and the calcination time is 3 hours.

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