An integrated device for in-situ power generation and extraction of coal seam gas and its application method

Abstract

This invention discloses an integrated device for in-situ power generation and extraction of coal seam gas and its usage method, relating to the field of coal seam gas control and utilization technology. An underground in-situ installation mechanism is used for anchoring coal seam boreholes and includes a gas storage chamber. A gas pretreatment mechanism is located inside, performing multi-stage purification of the raw gas entering the storage chamber. An outlet pipe connects to the storage chamber. A first negative pressure generating mechanism is detachably connected to the outlet pipe, generating negative pressure in the storage chamber in a first operating mode. A mechanical extraction mechanism can replace the first negative pressure generating mechanism, switching to a second operating mode. A bidirectional electrochemical energy conversion mechanism is connected to the underground in-situ installation mechanism and the storage chamber; in the first operating mode, it generates electricity using high-concentration gas, and in the second operating mode, it produces methane using electrical energy. An integrated control system is electrically connected to each mechanism, coordinating operation according to a preset program or remote commands to achieve switching between the two operating modes and stable operation. This invention enables the coordinated operation of in-situ collection, power generation, and extraction of coal seam gas.

Description

Technical Field

[0001] This invention relates to the field of coalbed methane control and utilization technology, and in particular to an integrated device for in-situ power generation and extraction of coalbed methane and its usage method. Background Technology

[0002] Coalbed methane (CBM), as a by-product of coal mining, has high utilization value. Currently, coalbed methane treatment technologies are mainly divided into two categories: extraction and emission, and resource utilization, but both have significant shortcomings. Extraction and emission equipment has a single function; after extraction, the methane is often directly discharged or only undergoes simple harmless treatment, wasting resources and polluting the environment. Resource utilization equipment, mainly gas power generation equipment, has several core defects: First, it requires a complex gas collection system and long-distance pipelines, making it impossible to collect and utilize the methane directly in situ. Leakage and losses are prone to occur during transportation, increasing operating costs and safety risks. Second, the core power generation components have irreversible functions, only capable of single power generation, and are independent of the extraction equipment, unable to flexibly switch operating modes according to on-site methane conditions and utilization needs. Furthermore, traditional technical solutions also suffer from a lack of function switching mechanisms, reliance on external equipment for installation with cumbersome processes, and core components being mostly made of metal, making them susceptible to damage and aging in harsh environments, resulting in low system integration, high investment, and poor stability.

[0003] Therefore, there is an urgent need for a new type of device that can integrate the functions of in-situ coal seam gas collection, power generation and extraction, and can flexibly switch working modes according to real-time working conditions such as on-site gas concentration and pressure, in order to solve the problems of single equipment function, low integration, low resource utilization, high safety risks and poor adaptability in the existing technology, thereby improving the economy, safety and environmental protection of coal seam gas management. Summary of the Invention

[0004] The purpose of this invention is to provide an integrated device for in-situ power generation and extraction of coal seam gas and its usage method, in order to solve the problems existing in the prior art. It aims to achieve the coordinated operation of coal seam gas collection, power generation and extraction in situ through structural innovation and functional integration, and has the ability to adjust the operating mode in real time according to key parameters such as gas concentration and pressure. This overcomes the bottlenecks of traditional technologies such as independent equipment operation, resource waste, prominent safety hazards and insufficient adaptability, and provides a brand-new solution for the efficient, safe and environmentally friendly utilization of coal seam gas.

[0005] To achieve the above objectives, the present invention provides the following solution: This invention provides an integrated device for in-situ power generation and extraction of coal seam gas, comprising: an underground in-situ installation mechanism, a gas pretreatment mechanism, a gas outlet pipe, a first negative pressure generating mechanism, a mechanical extraction mechanism, a bidirectional electrochemical energy conversion mechanism, and an integrated control system. The underground in-situ installation mechanism is used to form a borehole in the coal seam and can be mechanically anchored to the coal seam. A gas storage chamber capable of communicating with or being closed via the borehole is provided within the underground in-situ installation mechanism. The gas pretreatment mechanism is located within the underground in-situ installation mechanism and at the end where the gas storage chamber communicates with the borehole, enabling multi-stage purification of the raw gas entering the gas storage chamber from the borehole. The gas outlet pipe is fixedly connected to the underground in-situ installation mechanism and communicates with the gas storage chamber. The first negative pressure generating mechanism is detachably connected to and communicates with the gas outlet pipe, and is used to generate gas in the gas storage chamber in a first operating mode. The negative pressure is used to actively collect methane; the mechanical extraction mechanism is used to replace the first negative pressure generating mechanism and is detachably connected to the gas outlet pipe to switch to the second working mode; the bidirectional electrochemical energy conversion mechanism is selectively connected to the downhole in-situ installation mechanism and the gas storage chamber, and can use the high concentration of methane collected in the gas storage chamber to perform an electrochemical oxidation reaction to generate electricity in the first working mode, and can use the electricity to achieve a reverse electrochemical reduction reaction to produce methane in the second working mode; the integrated control system is electrically connected to the downhole in-situ installation mechanism, the methane pretreatment mechanism, the first negative pressure generating mechanism, the mechanical extraction mechanism and the bidirectional electrochemical energy conversion mechanism respectively, and is used to coordinate the working status of each mechanism according to a preset program or remote control command to achieve switching and stable operation between the first working mode and the second working mode.

[0006] Preferably, the downhole in-situ installation mechanism includes a sealing shell, a drilling forming assembly, and an anchoring assembly. The gas storage chamber is formed inside the sealing shell. The drilling forming assembly is disposed at the front end of the sealing shell and is used to drill the borehole in the coal seam. The drilling forming assembly includes at least a radially deployable drill bit and a drive rod hinged to the drill bit. The axial movement of the drive rod can drive the drill bit to switch between a retracted state and an deployed state. Multiple anchoring assemblies are arranged at intervals along the circumference of the sealing shell, and the anchoring assemblies are used for mechanical anchoring to the coal seam around the borehole.

[0007] Preferably, it further includes an air intake channel and a silencer check valve. The air intake channel is used to connect the gas storage chamber and the borehole. The silencer check valve is installed on the air intake channel. The gas pretreatment mechanism is installed on the air intake channel and located on the side of the silencer check valve away from the gas storage chamber.

[0008] Preferably, the gas pretreatment mechanism includes a dust adsorption layer, a filter screen, and a separation membrane arranged sequentially from the drill bit to the gas storage chamber. The dust adsorption layer is filled with a high-efficiency adsorption material to adsorb fine impurity particles and trace amounts of harmful substances in the gas. The filter screen is made of high-density metal mesh to intercept large particles of dust and coal slag in the gas. The separation membrane is made of high-performance molecular sieve material to remove harmful impurities in the gas.

[0009] Preferably, the bidirectional electrochemical energy conversion mechanism includes a combustion chamber, a resistance wire, a first valve, a second negative pressure generating mechanism, a second valve, and a solid oxide fuel cell stack. The combustion chamber is disposed in the gas storage chamber and selectively connected to the gas storage chamber through the first valve. The output end of the second negative pressure generating mechanism is connected to the combustion chamber to generate negative pressure in the combustion chamber. The resistance wire is disposed in the combustion chamber and electrically connected to the integrated control system, and is used to heat up to ignite the gas in the combustion chamber when a start signal is received. The fuel inlet of the solid oxide fuel cell stack is selectively connected to the gas storage chamber through the second valve, and its oxidant inlet is connected to the outside air. The power output end of the solid oxide fuel cell stack can be electrically connected to external electrical equipment or energy storage devices to convert the chemical energy of gas into electrical energy in the first working mode. When switching to the second working mode, the solid oxide fuel cell stack can use electrical energy to reduce carbon dioxide and water to methane through a reverse electrochemical reduction reaction.

[0010] Preferably, the solid oxide fuel cell stack includes a reforming reaction chamber, an anode gas chamber, a cathode gas chamber, a battery, a first pipe, a first three-way valve, a second pipe, a second three-way valve, an oxygen-enriched air pump, and a tail gas collection tank. The reforming reaction chamber, the anode gas chamber, and the cathode gas chamber are arranged sequentially and connected. The reforming reaction chamber is selectively connected to the gas storage chamber through the second valve. One end of the first pipe is connected to the cathode gas chamber, and the other end is connected to the oxygen-enriched air pump and the tail gas collection tank through the first three-way valve. One end of the second pipe is connected to the anode gas chamber, and the other end is connected to the tail gas collection tank and a methane collection device through the second three-way valve.

[0011] Preferably, it also includes a temperature and humidity sensor, a tail gas recirculation pipe and a third valve. The temperature and humidity sensor is located on the side of the second valve near the reforming reaction chamber. One end of the tail gas recirculation pipe is connected to the anode gas chamber and the other end is connected to the gas storage chamber.

[0012] Preferably, both the first negative pressure generating mechanism and the second negative pressure generating mechanism are Venturi tube structures. The Venturi tube structure includes a contraction section, a throat, a diffuser section, a quick-release tube, a polymer separation membrane, a rotary valve, and a gas concentration sensor. The inlet end of the contraction section is connected to an external gas source. The throat is located between the contraction section and the diffuser section, and the diameter of the throat is smaller than the diameters of the contraction section and the diffuser section. One end of the quick-release tube is integrally connected to and communicates with the throat, and the other end is detachably connected to and communicates with the gas outlet pipe. The gas concentration sensor is located on the quick-release tube. The polymer separation membrane is located on the quick-release tube and on the side of the gas concentration sensor closer to the throat. The rotary valve is located on the quick-release tube and on the side of the polymer separation membrane closer to the throat.

[0013] Preferably, the mechanical extraction mechanism includes an extraction pump and an extraction pipe. One end of the gas outlet pipe extending out of the gas storage chamber is provided with an external thread quick-release structure. One end of the extraction pipe is provided with an internal thread quick-release structure that matches the external thread quick-release structure, and the other end is connected to the extraction pump. The end of the extraction pump away from the extraction pipe is connected to a gas delivery main pipe. The end of the quick-release pipe used to connect to the gas outlet pipe is also provided with an internal thread quick-release structure that matches the external thread quick-release structure.

[0014] The present invention also provides a method for using the integrated coal seam gas in-situ power generation and extraction device as described in any of the preceding claims, comprising the following steps: In-situ installation steps: Use the underground in-situ installation mechanism to form a borehole at the target location in the coal seam, and complete the mechanical anchoring of the underground in-situ installation mechanism to the coal seam, so that the gas storage chamber and the coal seam gas source are connected through the borehole; First operating mode: In-situ power generation steps: S1: Negative pressure collection and purification: Connect the first negative pressure generating mechanism to the gas outlet pipe, start the first negative pressure generating mechanism to generate negative pressure in the gas storage chamber, thereby drawing the original gas in the coal seam into the gas storage chamber through the borehole, and storing it in the gas storage chamber after passing through the gas pretreatment mechanism for multi-stage purification. S2: High-concentration gas utilization: When the gas in the gas storage chamber reaches a predetermined concentration, the bidirectional electrochemical energy conversion mechanism is controlled to connect with the gas storage chamber, and the high-concentration gas stored therein is used to carry out an electrochemical oxidation reaction, directly converting the chemical energy of the gas into electrical energy output. Second operating mode: Enhanced extraction and methane regeneration steps: T1: Mode switching: Disconnect the first negative pressure generating mechanism from the air outlet pipe and connect the mechanical extraction mechanism to the air outlet pipe; T2: Collaborative operation: Activate the mechanical extraction mechanism to actively extract coal seam gas; at the same time, control the bidirectional electrochemical energy conversion mechanism to switch to the reverse reaction state, and use electrical energy to carry out a reverse electrochemical reduction reaction to produce methane; T3: Mixed output: The purified gas directly extracted by the mechanical extraction mechanism and the methane regenerated by the bidirectional electrochemical energy conversion mechanism are transported to the ground or a designated storage device. Integrated control steps: Through the integrated control system, the switching, start-stop and collaborative operation parameters between the in-situ installation steps, the first working mode steps and the second working mode steps are automatically or semi-automatically coordinated and controlled according to the preset program or remote command, to ensure the stable operation of the device.

[0015] The present invention achieves the following technical effects compared to the prior art: This invention provides an integrated device for in-situ coal seam gas power generation and extraction, and its usage method. The device is directly fixed and drilled into the coal seam via an underground in-situ installation mechanism, simplifying the installation process, effectively preventing borehole collapse, and significantly increasing the utilization rate of coal seam boreholes. The gas pretreatment mechanism, located in the air intake channel, performs multi-stage purification of the raw gas, ensuring the quality of the gas entering subsequent processing stages and providing pure raw materials for efficient power generation and methane regeneration. The bidirectional electrochemical energy conversion mechanism not only efficiently converts the chemical energy of gas into electrical energy in the first operating mode, but also utilizes electrical energy to produce methane through a reverse electrochemical reduction reaction in the second operating mode. This achieves bidirectional energy conversion and functional reversibility, greatly improving the device's flexibility and resource utilization. Both the first negative pressure generating mechanism and the mechanical extraction mechanism adopt a quick-release connection structure with the gas outlet pipe. Combined with the instructions of the integrated control system, it can quickly switch operating modes to adapt to the processing needs under different gas concentrations and pressures. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a front view sectional view of the integrated in-situ power generation and extraction device for coalbed methane provided by the present invention. Figure 2 A side view of the integrated coal seam gas in-situ power generation and extraction device provided by the present invention; Figure 3A schematic diagram of the Chinese-language tube structure of the integrated coal seam gas in-situ power generation and extraction device provided by the present invention. Figure 4 This is a schematic diagram of the gas pretreatment mechanism in the integrated coal seam gas in-situ power generation and extraction device provided by the present invention. In the diagram: 11. Sealed outer shell; 12. Drilling and forming assembly; 13. Anchoring assembly; 14. Gas storage chamber; 15. Air inlet channel; 16. Silencing check valve; 20. Gas pretreatment mechanism; 21. Dust adsorption layer; 22. Filter screen; 23. Separation membrane; 30. Venturi tube structure; 32. Contraction section; 33. Throat; 34. Diffusion section; 35. Quick-release tube; 36. Polymer separation membrane; 37. Rotary valve; 38. Gas concentration sensor; 41. Ignition chamber; 42. Resistance wire; 43. First valve; 44. Second valve; 45. Solid oxide fuel cell stack; 451. Reforming reaction chamber; 452. Anode gas chamber; 453. Cathode gas chamber; 454. Battery; 455. First pipeline; 456. First three-way valve; 457. Second pipeline; 458. Second three-way valve; 459. Oxygen-enriched air pump; 460. Exhaust gas collection tank; 461. Temperature and humidity sensor; 462. Exhaust gas recirculation pipeline; 463. Third valve. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] The purpose of this invention is to provide an integrated device for in-situ power generation and extraction of coal seam gas and its usage method, in order to solve the problems existing in the prior art. It aims to achieve the coordinated operation of coal seam gas collection, power generation and extraction in situ through structural innovation and functional integration, and has the ability to adjust the operating mode in real time according to key parameters such as gas concentration and pressure. This overcomes the bottlenecks of traditional technologies such as independent equipment operation, resource waste, prominent safety hazards and insufficient adaptability, and provides a brand-new solution for the efficient, safe and environmentally friendly utilization of coal seam gas.

[0020] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] Example 1 This invention provides an integrated device for in-situ power generation and extraction of coal seam gas, as shown in Figures 1-4. It includes: an underground in-situ installation mechanism, a gas pretreatment mechanism 20, a gas outlet pipe, a first negative pressure generating mechanism, a mechanical extraction mechanism, a bidirectional electrochemical energy conversion mechanism, and an integrated control system. The underground in-situ installation mechanism is used to form a borehole in the coal seam and can be mechanically anchored to the coal seam. A gas storage chamber 14, which can be connected to or closed by the borehole, is provided within the underground in-situ installation mechanism. The gas pretreatment mechanism 20 is located within the underground in-situ installation mechanism and at the end of the gas storage chamber 14 that connects to the borehole, enabling multi-stage purification of the raw gas entering the gas storage chamber 14 from the borehole. The gas outlet pipe is fixedly connected to the underground in-situ installation mechanism and communicates with the gas storage chamber 14. The first negative pressure generating mechanism is detachably connected to and communicates with the gas outlet pipe, used to generate negative pressure in the gas storage chamber 14 in a first working mode to actively collect gas. The mechanical extraction mechanism is used to replace the first negative pressure generating mechanism. The structure is detachably connected to and communicates with the gas outlet pipe to switch to the second working mode; the bidirectional electrochemical energy conversion mechanism is selectively connected to the underground in-situ installation mechanism and the gas storage chamber 14, and can use the high concentration of gas collected in the gas storage chamber 14 to carry out electrochemical oxidation reaction to generate electricity in the first working mode, and can use the electricity to carry out reverse electrochemical reduction reaction to prepare methane in the second working mode; the integrated control system is electrically connected to the underground in-situ installation mechanism, the gas pretreatment mechanism 20, the first negative pressure generating mechanism, the mechanical extraction mechanism and the bidirectional electrochemical energy conversion mechanism respectively, and is used to coordinate the working status of each mechanism according to the preset program or remote control command to realize the switching and stable operation between the first working mode and the second working mode. This overall structural design constructs a coal seam gas treatment device with comprehensive functions and flexible switching working modes. Through the collaborative work of various components, the system can perform multiple functions such as gas collection, purification, power generation, and extraction in situ within the coal seam. This solves the problems of single-function and isolated equipment in traditional coal seam gas treatment methods. After drilling is completed, the device switches to a state of connection between the gas storage chamber and the coal seam gas source in situ, allowing for rapid entry into the gas collection stage without removing the device from the borehole. This design not only reduces the procedures and time costs of underground operations but also avoids safety risks such as borehole instability and gas leakage that may result from frequent device movement or disassembly. It significantly improves borehole utilization, effectively prevents resource waste caused by borehole collapse, increases the efficiency of gas resource utilization, reduces treatment costs, and enhances the adaptability of the device to different working scenarios.

[0022] In a preferred embodiment, the in-situ installation mechanism includes a sealing shell 11, a drilling forming assembly 12, and an anchoring assembly 13. A gas storage chamber 14 is formed inside the sealing shell 11. The drilling forming assembly 12 is disposed at the front end of the sealing shell 11 and is used to drill holes in the coal seam. The drilling forming assembly 12 includes at least a radially deployable drill bit and a drive rod hinged to the drill bit. The axial movement of the drive rod can drive the drill bit to switch between a retracted state and an extended state. Multiple anchoring assemblies 13 are arranged at intervals along the circumference of the sealing shell 11, and the anchoring assemblies 13 are used for mechanical anchoring to the coal seam around the borehole. This design enables the device to complete the drilling operation autonomously in the coal seam without relying on external drilling equipment, thus simplifying the installation process. The radially expandable drill bit and drive rod work together to facilitate the overall insertion of the device into the predetermined position in the retracted state. After completing the borehole and switching to the expanded state, the borehole can be connected to the gas storage chamber 14. In addition, the anchoring components 13 are spaced around the sealing shell 11 in the circumference, which can mechanically anchor the device to the coal seam around the borehole from multiple directions. This greatly enhances the installation stability of the device in the coal seam and prevents the device from shifting or falling off due to changes in the geological conditions of the coal seam or pressure fluctuations during the gas extraction process. This provides a reliable structural foundation for the subsequent stable collection and treatment of gas.

[0023] In a preferred embodiment, the end of the sealing shell 11 furthest from the drilling and forming assembly 12 is sealed and connected via a cover plate. The anchoring assembly 13 includes multiple anchor plates and anchor bolts. One end of the anchor plate is fixedly connected to the cover plate and is evenly arranged along the axis of the cover plate. The anchor bolts pass through the anchor plates and are anchored to the coal seam. The sealing shell 11 is sealed by the cover plate, effectively preventing gas leakage, ensuring the airtightness of the gas storage chamber 14, and improving gas collection efficiency. The arrangement of the anchor plates and anchor bolts ensures uniform distribution of anchoring force, enhances the stability of the connection between the device and the coal seam, further guarantees the stability of the device in complex underground environments, avoids gas leakage or device damage due to loosening, and ensures the safe and reliable operation of the entire device.

[0024] In a preferred embodiment, the system further includes an air inlet channel 15 and a silencer check valve 16. The air inlet channel 15 connects the gas storage chamber 14 and the borehole. The silencer check valve 16 is installed on the air inlet channel 15. The gas pretreatment mechanism 20 is installed on the air inlet channel 15 and located on the side of the silencer check valve 16 away from the gas storage chamber 14. The air inlet channel 15 provides a pathway for gas to enter the gas storage chamber 14. The silencer check valve 16 prevents gas backflow, ensuring stable gas storage in the gas storage chamber 14 and avoiding disruption to the normal operation of the device due to gas backflow. It also reduces noise generated by gas flow, minimizing interference with the downhole working environment. The gas pretreatment mechanism 20, positioned in this location, can promptly purify the gas before it enters the gas storage chamber 14, ensuring the quality of the gas entering the gas storage chamber 14.

[0025] In a preferred embodiment, the gas pretreatment mechanism 20 includes a dust adsorption layer 21, a filter screen 22, and a separation membrane 23 arranged sequentially from the drill bit to the gas storage chamber 14. The dust adsorption layer 21 is filled with a high-efficiency adsorption material to adsorb fine impurity particles and trace amounts of harmful substances in the gas. The filter screen 22 is a high-density metal mesh used to intercept large particles of dust and coal slag in the gas. The separation membrane 23 uses a high-performance molecular sieve material to remove harmful impurities in the gas. This multi-stage purification structure can comprehensively remove various impurities from the gas. The dust adsorption layer 21 effectively adsorbs fine impurities and trace amounts of harmful substances, the filter screen 22 intercepts large particles of dust and coal slag, and the separation membrane 23 removes harmful impurities, thus improving the purity of the gas. High-purity gas is beneficial for subsequent power generation or extraction work, reduces damage to equipment from impurities, improves power generation efficiency, ensures the quality of extracted gas, and reduces the risk of safety accidents caused by impurities.

[0026] In a preferred embodiment, the bidirectional electrochemical energy conversion mechanism includes an ignition chamber 41, a resistance wire 42, a first valve 43, a second negative pressure generating mechanism, a second valve 44, and a solid oxide fuel cell stack 45. The ignition chamber 41 is disposed within the gas storage chamber 14 and is selectively connected to the gas storage chamber 14 via the first valve 43. The output end of the second negative pressure generating mechanism is connected to the ignition chamber 41 to generate a negative pressure within the ignition chamber 41. The resistance wire 42 is disposed within the ignition chamber 41 and electrically connected to the integrated control system, and is used to heat up upon receiving a start signal to ignite the gas within the ignition chamber 41. The fuel inlet of the solid oxide fuel cell stack 45 is selectively connected to the gas storage chamber 14 via a second valve 44, while its oxidant inlet is connected to the outside air. The power output of the solid oxide fuel cell stack 45 can be electrically connected to external electrical equipment or energy storage devices to convert the chemical energy of gas into electrical energy in the first operating mode. When switching to the second operating mode, the solid oxide fuel cell stack 45 can use electrical energy to reduce carbon dioxide and water to methane through a reverse electrochemical reduction reaction. This bidirectional electrochemical energy conversion mechanism achieves efficient utilization of gas energy and bidirectional conversion of functions. In power generation mode, gas is ignited through the combustion chamber 41, and the solid oxide fuel cell stack 45 converts the chemical energy of gas into electrical energy to power underground equipment or external electrical equipment, improving the energy utilization value of gas. In extraction mode, it can reversely utilize electrical energy to reduce carbon dioxide and water to methane, realizing resource recycling, further improving the utilization rate of gas resources, and reducing carbon emissions, thus having good environmental benefits. The collaborative work of the components and the selective connectivity design enable the mechanism to be flexibly adjusted according to different working modes, ensuring the stability and efficiency of the work.

[0027] In a preferred embodiment, the solid oxide fuel cell stack 45 includes a reforming reaction chamber 451, an anode gas chamber 452, a cathode gas chamber 453, a battery 454, a first pipe 455, a first three-way valve 456, a second pipe 457, a second three-way valve 458, an oxygen-enriched air pump 459, and a tail gas collection tank 460. The reforming reaction chamber 451, the anode gas chamber 452, and the cathode gas chamber 453 are arranged sequentially and connected. The reforming reaction chamber 451 is selectively connected to the gas storage chamber 14 through the second valve 44. One end of the first pipe 455 is connected to the cathode gas chamber 453, and the other end is connected to the oxygen-enriched air pump 459 and the tail gas collection tank 460 through the first three-way valve 456. One end of the second pipe 457 is connected to the anode gas chamber 452, and the other end is connected to the tail gas collection tank 460 and the methane collection device through the second three-way valve 458. The detailed structural design ensures that the functions of each part of the solid oxide fuel cell stack 45 are clear and highly coordinated during power generation and reverse reaction processes. Reforming chamber 451 reforms the gas to provide suitable fuel gas for subsequent electrochemical reactions. Electrochemical reactions occur in anode chamber 452 and cathode chamber 453 to achieve energy conversion. First pipe 455 and first three-way valve 456 control the supply of oxygen-enriched air and the collection of exhaust gas, while second pipe 457 and second three-way valve 458 are used for exhaust gas treatment and methane collection. This design ensures efficient power generation and the rational flow and collection of substances during the reverse reaction to produce methane, further optimizing the gas energy conversion and resource utilization process.

[0028] In a preferred embodiment, the system further includes a temperature and humidity sensor 461, a tail gas recirculation pipe 462, and a third valve 463. The temperature and humidity sensor 461 is located on the side of the second valve 44 near the reforming reaction chamber 451. One end of the tail gas recirculation pipe 462 is connected to the anode gas chamber 452, and the other end is connected to the gas storage chamber 14. The temperature and humidity sensor 461 can monitor the temperature and humidity of the gas entering the reforming reaction chamber 451 in real time, providing data support for adjusting reaction conditions and ensuring that the reforming reaction is carried out under optimal temperature and humidity conditions, thereby improving reaction efficiency and stability. The tail gas recirculation pipe 462 and the third valve 463 allow the tail gas generated in the anode gas chamber 452 to be partially recirculated back to the gas storage chamber 14, realizing the recycling of tail gas. On the one hand, this can regulate the gas composition and flow rate entering the reforming reaction chamber 451; on the other hand, it reduces tail gas emissions, improves resource utilization, and lowers production costs.

[0029] In a preferred embodiment, both the first and second negative pressure generating mechanisms are Venturi tube structures 30. The Venturi tube structure 30 includes a constriction section 32, a throat 33, a diffuser section 34, a quick-release tube 35, a polymer separation membrane 36, a rotary valve 37, and a gas concentration sensor 38. The inlet end of the constriction section 32 is connected to an external gas source. The throat 33 is located between the constriction section 32 and the diffuser section 34, and the diameter of the throat 33 is smaller than the diameters of the constriction section 32 and the diffuser section 34. The quick-release tube... One end of tube 35 is integrally connected to and communicates with throat tube 33, while the other end is detachably connected to and communicates with outlet tube. Gas concentration sensor 38 is mounted on quick-release tube 35. Polymer separation membrane 36 is mounted on quick-release tube 35 and located on the side of gas concentration sensor 38 near throat tube 33. Rotary valve 37 is mounted on quick-release tube 35 and located on the side of polymer separation membrane 36 near throat tube 33. Venturi tube structure 30 utilizes fluid dynamics principles to generate negative pressure, actively collecting gas and improving gas collection efficiency. Quick-release tube 35 facilitates connection and disconnection with outlet tube, allowing for easy replacement of the first negative pressure generating mechanism and mechanical extraction mechanism under different operating modes. Polymer separation membrane 36 can selectively separate gas, increasing gas concentration, which is beneficial for subsequent power generation or extraction operations. Rotary valve 37 controls gas flow, and gas concentration sensor 38 monitors gas concentration in real time, providing data for the integrated control system to precisely control the gas collection process and ensure the stability and efficiency of the device.

[0030] In a preferred embodiment, the mechanical extraction mechanism includes an extraction pump and an extraction pipe. One end of the gas outlet pipe extending from the gas storage chamber 14 is equipped with an external thread quick-release structure. One end of the extraction pipe is equipped with an internal thread quick-release structure matching the external thread quick-release structure, and the other end is connected to the extraction pump. The end of the extraction pump away from the extraction pipe is connected to a gas delivery main pipe. The end of the quick-release pipe 35 used to connect to the gas outlet pipe is also equipped with an internal thread quick-release structure matching the external thread quick-release structure. The quick-release structure design of the mechanical extraction mechanism allows for quick replacement of the first negative pressure generating mechanism with the mechanical extraction mechanism when switching to extraction mode, simplifying and improving work efficiency. The matching of the external and internal thread quick-release structures ensures the sealing of the connection, preventing gas leakage and ensuring the safe operation of the extraction work. The extraction pump and gas delivery main pipe enable effective extraction of gas from the coal seam and delivery to a designated location, meeting the gas extraction needs in different scenarios.

[0031] Example 2 This embodiment also provides a method for using the integrated coal seam gas in-situ power generation and extraction device as described in any of Embodiment 1, including the following steps: 1. Device Installation Operation of the underground in-situ installation mechanism: Transport the underground in-situ installation mechanism to the predetermined location in the coal seam. Use the drive rod to retract the radially deployable drill bit, and then use the drill forming assembly 12 to drill a hole in the coal seam. The drilling depth and diameter must meet the device design requirements to ensure stable installation and effective gas collection. The drilling diameter is 150mm, and the depth is 1200mm (the overall length of the device is 1000mm). After drilling is completed, move the drive rod axially to extend the drill bit and bring it into close contact with the borehole wall.

[0032] Anchoring assembly 13 installation: Along the circumference of the sealing shell 11, the anchoring plates are anchored to the coal seam around the borehole using M16 anchoring bolts. The anchoring plates are evenly distributed along the axis of the cover plate to ensure uniform anchoring force, making the device firmly connected to the coal seam and preventing displacement of the device during operation.

[0033] Other component connections: Install the air intake channel 15, connecting the gas storage chamber 14 and the borehole. Install a silencer check valve 16 on the air intake channel 15. Install the gas pretreatment mechanism 20 on the air intake channel 15, located on the side of the silencer check valve 16 away from the gas storage chamber 14. Connect the gas outlet pipe, fixing it to the downhole in-situ installation mechanism and connecting it to the gas storage chamber 14.

[0034] 2. First operating mode (power generation mode) Gas collection and pretreatment: The first negative pressure generating mechanism is connected to the outlet pipe via a quick-release pipe 35. The inlet end of the constriction section 32 of the first negative pressure generating mechanism is connected to an external air source. After the external air source supplies air, compressed air at a pressure of 0.4 MPa is introduced, creating a negative pressure at the throat 33 of the Venturi tube structure 30, which in turn generates a negative pressure of -0.05 MPa in the gas storage chamber 14. Under the action of negative pressure, the original gas in the coal seam enters the gas pretreatment mechanism 20 through the borehole and the air intake channel 15. The gas passes through the dust adsorption layer 21, the filter screen 22, and the separation membrane 23 in sequence, removing fine impurities, trace amounts of harmful substances, large dust particles, coal slag, and other harmful impurities, resulting in purified gas that enters the gas storage chamber 14. A silencer check valve 16 prevents gas backflow and reduces gas flow noise. A gas concentration sensor 38 monitors the gas concentration in the quick-release pipe 35 in real time and transmits the data to the integrated control system.

[0035] The bidirectional electrochemical energy conversion mechanism is activated: When the gas concentration in the gas storage chamber 14 reaches 30%, the integrated control system sends a signal to open the first valve 43, connecting the ignition chamber 41 to the gas storage chamber 14. The second negative pressure generating mechanism is activated, creating a negative pressure of -0.05 MPa in the ignition chamber 41, drawing some of the gas from the gas storage chamber 14 into the ignition chamber 41. The first valve 43 is closed, and the integrated control system controls the resistance wire 42 to be energized and heated, igniting the gas in the ignition chamber 41. The combustion of the gas produces high-temperature gas at approximately 900°C. The energization of the resistance wire is stopped, and after a 3-second delay, the first valve 43 is reopened. The high-temperature gas mixes with the gas in the gas storage chamber, forming a mixture at approximately 800°C.

[0036] Power generation process: Open the second valve 44 to allow the high-concentration methane in the gas storage chamber 14 to enter the reforming reaction chamber 451 of the solid oxide fuel cell stack 45. In the reforming reaction chamber 451, a reforming reaction is carried out under the condition of a water-to-carbon ratio of 3:1. The reforming reaction generates carbon monoxide and hydrogen. The reformed gas enters the anode gas chamber. At the same time, the oxygen-enriched air pump 459 introduces oxygen-enriched air (oxygen concentration of 30%) into the cathode gas chamber 453 through the first three-way valve 456. An electrochemical reaction occurs at the anode and cathode, with an output voltage of 24V and an output power of 500W. The electrical energy is stored in the battery (4).

[0037] Process monitoring and regulation: Temperature and humidity sensor 461 monitors the temperature and humidity of the gas entering the reforming reaction chamber 451 in real time and feeds the data back to the integrated control system. Based on the temperature and humidity data, the integrated control system adjusts the tail gas return flow rate in the tail gas return pipe 462 by controlling the opening of the third valve 463, thereby adjusting the gas composition and temperature and humidity entering the reforming reaction chamber 451 to ensure that the reforming reaction proceeds under optimal conditions. When the humidity is below 30%RH or the temperature is below 800℃ (or both occur simultaneously), the opening of the third valve 463 is adjusted to increase the tail gas return flow rate and increase the humidity or temperature of the mixed gas. Part of the tail gas generated during power generation enters the tail gas collection tank 460 for storage through the first pipe 455 and the first three-way valve 456.

[0038] 3. Mode switching Power generation shutdown mode: Upon receiving the mode switching command, the integrated control system shuts down the oxygen-enriched air pump 459, ceasing the supply of oxygen-enriched air to the cathode chamber 453. It closes the second valve 44, disconnecting the gas storage chamber 14 from the solid oxide fuel cell stack 45. It stops the operation of the resistance wire 42 and closes the first valve 43, completely isolating the combustion chamber 41 from the gas storage chamber 14.

[0039] Replacement mechanism: Disconnect the quick-release pipe 35 of the first negative pressure generating mechanism from the air outlet pipe, and connect the extraction pipe of the mechanical extraction mechanism to the external thread quick-release structure of the air outlet pipe through the internal thread quick-release structure, ensuring a good seal.

[0040] 4. Second working mode (sampling mode) Gas extraction: Start the extraction pump, which generates negative pressure and extracts the gas from the gas storage chamber 14 and the coal seam through the extraction pipe. After passing through the extraction pump, the gas is transported to the designated storage or treatment equipment through the gas transmission main pipe.

[0041] Reverse electrochemical reduction reaction: The integrated control system controls the solid oxide fuel cell stack 45 to perform a reverse electrochemical reduction reaction using electrical energy. The exhaust gas (containing carbon dioxide and water, etc.) in the exhaust gas collection tank 460 enters the cathode gas chamber 453 through the second three-way valve 458. Inside the solid oxide fuel cell stack 45, electrical energy drives the reverse reaction, reducing carbon dioxide and water to methane. The generated methane is transported to the methane collection device through the second pipe 457 and the second three-way valve 458.

[0042] Throughout the entire operation of the device, the integrated control system monitors and coordinates the working status of the downhole in-situ installation mechanism, the gas pretreatment mechanism 20, the first negative pressure generating mechanism (or mechanical extraction mechanism), and the bidirectional electrochemical energy conversion mechanism in real time according to the preset program or remote control command, so as to ensure smooth switching and stable operation between the first working mode and the second working mode.

[0043] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. An integrated device for in-situ power generation and extraction of coal seam gas, characterized in that: include: An underground in-situ installation mechanism is used to form a borehole in a coal seam and can be mechanically anchored to the coal seam. The underground in-situ installation mechanism is provided with a gas storage chamber that can communicate with or be closed to the borehole. A gas pretreatment mechanism is provided in the downhole in-situ installation mechanism and located at the end where the gas storage chamber communicates with the borehole, so as to perform multi-stage purification on the raw gas entering the gas storage chamber from the borehole. The gas outlet pipe is fixedly connected to the downhole in-situ installation mechanism and communicates with the gas storage chamber. The first negative pressure generating mechanism is detachably connected to and communicates with the gas outlet pipe, and is used to generate negative pressure in the gas storage chamber in the first working mode to actively collect gas. A mechanical extraction mechanism is used to replace the first negative pressure generating mechanism and detachably connect and communicate with the air outlet pipe to switch to a second working mode; A bidirectional electrochemical energy conversion mechanism is selectively connected to the downhole in-situ installation mechanism and the gas storage chamber. In the first working mode, it can use the high concentration of methane collected in the gas storage chamber to perform an electrochemical oxidation reaction to generate electrical energy. In the second working mode, it can use electrical energy to perform a reverse electrochemical reduction reaction to prepare methane. An integrated control system is electrically connected to the downhole in-situ installation mechanism, the gas pretreatment mechanism, the first negative pressure generating mechanism, the mechanical extraction mechanism, and the bidirectional electrochemical energy conversion mechanism, respectively. It is used to coordinate the working status of each mechanism according to a preset program or remote control command, so as to realize the switching and stable operation between the first working mode and the second working mode.

2. The integrated coal seam gas in-situ power generation and extraction device according to claim 1, characterized in that: The downhole in-situ installation mechanism includes a sealing shell, a drilling forming assembly, and an anchoring assembly. The gas storage chamber is formed inside the sealing shell. The drilling forming assembly is located at the front end of the sealing shell and is used to drill the borehole in the coal seam. The drilling forming assembly includes at least a radially deployable drill bit and a drive rod hinged to the drill bit. The axial movement of the drive rod can drive the drill bit to switch between a retracted state and an deployed state. Multiple anchoring assemblies are arranged at intervals along the circumference of the sealing shell, and the anchoring assemblies are used for mechanical anchoring to the coal seam around the borehole.

3. The integrated coal seam gas in-situ power generation and extraction device according to claim 2, characterized in that: It also includes an air intake channel and a silencer check valve. The air intake channel is used to connect the gas storage chamber and the borehole. The silencer check valve is installed on the air intake channel. The gas pretreatment mechanism is installed on the air intake channel and located on the side of the silencer check valve away from the gas storage chamber.

4. The integrated coal seam gas in-situ power generation and extraction device according to claim 3, characterized in that: The gas pretreatment mechanism includes a dust adsorption layer, a filter screen, and a separation membrane arranged sequentially from the drill bit to the gas storage chamber. The dust adsorption layer is filled with a high-efficiency adsorption material to adsorb fine impurity particles and trace amounts of harmful substances in the gas. The filter screen is made of high-density metal mesh to intercept large particles of dust and coal slag in the gas. The separation membrane is made of high-performance molecular sieve material to remove harmful impurities in the gas.

5. The integrated device for in-situ power generation and extraction of coal seam gas according to claim 1, characterized in that: The bidirectional electrochemical energy conversion mechanism includes a combustion chamber, a resistance wire, a first valve, a second negative pressure generating mechanism, a second valve, and a solid oxide fuel cell stack. The combustion chamber is located in the gas storage chamber and is selectively connected to the gas storage chamber through the first valve. The output end of the second negative pressure generating mechanism is connected to the combustion chamber to generate negative pressure in the combustion chamber. The resistance wire is located in the combustion chamber and electrically connected to the integrated control system, and is used to heat up to ignite the gas in the combustion chamber when a start signal is received. The fuel inlet of the solid oxide fuel cell stack is selectively connected to the gas storage chamber through the second valve, and its oxidant inlet is connected to the outside air. The power output end of the solid oxide fuel cell stack can be electrically connected to external electrical equipment or energy storage devices to convert the chemical energy of gas into electrical energy in the first working mode. When switching to the second working mode, the solid oxide fuel cell stack can use electrical energy to reduce carbon dioxide and water to methane through a reverse electrochemical reduction reaction.

6. The integrated coal seam gas in-situ power generation and extraction device according to claim 5, characterized in that: The solid oxide fuel cell stack includes a reforming reaction chamber, an anode gas chamber, a cathode gas chamber, a battery, a first pipe, a first three-way valve, a second pipe, a second three-way valve, an oxygen-enriched air pump, and a tail gas collection tank. The reforming reaction chamber, the anode gas chamber, and the cathode gas chamber are arranged sequentially and connected. The reforming reaction chamber is selectively connected to the gas storage chamber through the second valve. One end of the first pipe is connected to the cathode gas chamber, and the other end is connected to the oxygen-enriched air pump and the tail gas collection tank through the first three-way valve. One end of the second pipe is connected to the anode gas chamber, and the other end is connected to the tail gas collection tank and a methane collection device through the second three-way valve.

7. The integrated coal seam gas in-situ power generation and extraction device according to claim 6, characterized in that: It also includes a temperature and humidity sensor, a tail gas return pipe and a third valve. The temperature and humidity sensor is located on the side of the second valve near the reforming reaction chamber. One end of the tail gas return pipe is connected to the anode gas chamber and the other end is connected to the gas storage chamber.

8. The integrated device for in-situ power generation and extraction of coal seam gas according to claim 1, characterized in that: Both the first and second negative pressure generating mechanisms are venturi tube structures. Each venturi tube structure includes a contraction section, a throat, a diffuser section, a quick-release tube, a polymer separation membrane, a rotary valve, and a gas concentration sensor. The inlet end of the contraction section is connected to an external gas source. The throat is positioned between the contraction section and the diffuser section, and its diameter is smaller than that of both the contraction and diffuser sections. One end of the quick-release tube is integrally connected to and communicates with the throat, while the other end is detachably connected to and communicates with the outlet pipe. The gas concentration sensor is mounted on the quick-release tube. The polymer separation membrane is mounted on the quick-release tube and located on the side of the gas concentration sensor closest to the throat. The rotary valve is mounted on the quick-release tube and located on the side of the polymer separation membrane closest to the throat.

9. The integrated device for in-situ power generation and extraction of coal seam gas according to claim 8, characterized in that: The mechanical extraction mechanism includes an extraction pump and an extraction pipe. One end of the gas outlet pipe extending out of the gas storage chamber is provided with an external thread quick-release structure. One end of the extraction pipe is provided with an internal thread quick-release structure that matches the external thread quick-release structure, and the other end is connected to the extraction pump. The end of the extraction pump away from the extraction pipe is connected to a gas delivery main pipe. The end of the quick-release pipe used to connect to the gas outlet pipe is also provided with an internal thread quick-release structure that matches the external thread quick-release structure.

10. A method of using an integrated coal seam gas in-situ power generation and extraction device as described in any one of claims 1 to 9, characterized in that: Includes the following steps In-situ installation steps: Use the underground in-situ installation mechanism to form a borehole at the target location in the coal seam, and complete the mechanical anchoring of the underground in-situ installation mechanism to the coal seam, so that the gas storage chamber and the coal seam gas source are connected through the borehole; First operating mode: In-situ power generation steps: S1: Negative pressure collection and purification: Connect the first negative pressure generating mechanism to the gas outlet pipe, start the first negative pressure generating mechanism to generate negative pressure in the gas storage chamber, thereby drawing the original gas in the coal seam into the gas storage chamber through the borehole, and storing it in the gas storage chamber after passing through the gas pretreatment mechanism for multi-stage purification. S2: High-concentration gas utilization: When the gas in the gas storage chamber reaches a predetermined concentration, the bidirectional electrochemical energy conversion mechanism is controlled to connect with the gas storage chamber, and the high-concentration gas stored therein is used to carry out an electrochemical oxidation reaction, directly converting the chemical energy of the gas into electrical energy output. Second operating mode: Enhanced extraction and methane regeneration steps: T1: Mode switching: Disconnect the first negative pressure generating mechanism from the air outlet pipe and connect the mechanical extraction mechanism to the air outlet pipe; T2: Collaborative operation: Activate the mechanical extraction mechanism to actively extract coal seam gas; at the same time, control the bidirectional electrochemical energy conversion mechanism to switch to the reverse reaction state, and use electrical energy to carry out a reverse electrochemical reduction reaction to produce methane; T3: Mixed output: The purified gas directly extracted by the mechanical extraction mechanism and the methane regenerated by the bidirectional electrochemical energy conversion mechanism are transported to the ground or a designated storage device. Integrated control steps: Through the integrated control system, the switching, start-stop and collaborative operation parameters between the in-situ installation steps, the first working mode steps and the second working mode steps are automatically or semi-automatically coordinated and controlled according to the preset program or remote command, to ensure the stable operation of the device.

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