An underground coal seam heating system and method based on an oxygen-rich combustion furnace

Abstract

This application discloses an underground coal seam heating system and method based on an oxygen-enriched combustion furnace, relating to the field of multi-fluid heating technology for underground coal seams. The system includes: a cyclone separator, a combustion chamber, a flue, a pulverized coal silo, a steam turbine, a heat exchanger, a coal seam assembly, and a tailings treatment component. The cyclone separator inlet is connected to the pulverized coal silo and the main air supply unit via an inlet pipe and a primary air pipe, respectively. The cyclone separator outlet is connected to the combustion chamber inlet via the flue, and the combustion chamber outlet is connected to the heat exchanger inlet via a connecting pipe. The cyclone separator and the combustion chamber sidewalls are connected to the steam turbine inlet via a first connecting pipe and a second connecting pipe, respectively. The heat exchanger outlet and the steam turbine outlet are both connected to the coal seam assembly inlet via transition pipes. The coal seam assembly outlet is connected to the tailings treatment component inlet, and the tailings treatment component outlet is connected to both the heat exchanger inlet and the cyclone separator inlet via a return pipe. In this application, the anti-adhesion mechanism can prevent flue gas from adhering to the inner wall of the flue from a flow field control perspective.

Description

Technical Field

[0001] This invention relates to the field of multi-fluid heating technology for underground coal seams, specifically to an underground coal seam heating system and method based on an oxygen-enriched combustion furnace. Background Technology

[0002] Cyclone combustion power generation systems rely on the high-speed swirling of air carrying fuel within a cyclone to achieve intense combustion, creating an extremely high-temperature environment and flue gas. This heats the working fluid to generate high-temperature, high-pressure steam, which drives a turbine for efficient power generation. It boasts advantages such as stable combustion, high efficiency, and strong load regulation capabilities. Existing technologies, such as air staging and creating an oxygen-enriched atmosphere in the combustion chamber, can reduce the formation of thermal and fuel-based nitrogen oxides respectively. In-situ underground pyrolysis technology for oil-rich coal eliminates the need for coal seam mining, directly injecting heat to extract oil and gas. This technology is characterized by safety, environmental friendliness, high thermal efficiency, and high-quality oil and gas. Its core technology lies in heating methods that meet the requirements of heating efficiency, oil and gas yield, and thermal energy recycling.

[0003] The high energy consumption and cost of oxygen production in cyclone combustion power generation systems with air separation and oxygen enrichment hinder the large-scale application of the technology. Furthermore, the nitrogen byproduct of oxygen production is not effectively utilized, leading to resource waste and increased system costs. In the field of underground in-situ pyrolysis of oil-rich coal, the low permeability of the coal seam presents a challenge. Traditional single-heating media have insufficient heat transfer efficiency, resulting in slow pyrolysis rates and limited oil and gas yields. Additionally, there is a lack of efficient multi-media synergistic heating schemes, and breakthroughs in energy efficiency and material recycling during the heating process have not yet been achieved. Moreover, the high-temperature flue gas contains extremely high levels of impurities, which cannot escape the wall-hugging flow when passing through the flue, causing long-term damage and corrosion to the flue's inner wall.

[0004] Therefore, there is a need for an underground coal seam heating system and method based on an oxygen-enriched combustion furnace to solve the above-mentioned technical problems. Summary of the Invention

[0005] To achieve the above objectives, the present invention provides the following technical solution: On one hand, an underground coal seam heating system based on an oxygen-enriched combustion furnace includes: a cyclone separator, a combustion chamber, a flue, a pulverized coal silo, a steam turbine, a heat exchanger, a coal seam assembly, and a tailings treatment component.

[0006] The cyclone inlet is connected to the pulverized coal silo and the main air supply unit via an inlet pipe and a primary air pipe, respectively. The cyclone outlet is connected to the combustion chamber inlet via the flue. The combustion chamber outlet is connected to the heat exchanger inlet via a connecting pipe. The cyclone and the sidewalls of the combustion chamber are connected to the turbine inlet via a first connecting pipe and a second connecting pipe, respectively. The heat exchanger outlet and the steam turbine outlet are both connected to the coal seam group inlet through a transition pipe. The coal seam group outlet is connected to the tailings treatment component inlet. The tailings treatment component outlet is connected to the heat exchanger inlet and the cyclone inlet through a return pipe. The flue is equipped with a guide mechanism and multiple circumferentially arranged anti-sticking mechanisms.

[0007] Furthermore, as a preferred embodiment, the side wall of the cyclone is connected to a plurality of equidistant and tangentially arranged secondary air ducts, the ends of the plurality of secondary air ducts away from the cyclone are connected to the auxiliary air supply unit, the side wall of the combustion chamber away from the second connecting pipe is connected to the first outlet of the first separator through the combustion air duct, the second outlet of the first separator is connected to the inlet of the heat exchanger, and the inlet of the first separator is connected to the compressor.

[0008] Furthermore, as a preferred embodiment, the coal seam group includes: a sandstone layer, an oil-rich coal seam, a first injection well, a second injection well, and a discharge well; The sandstone layer is located at the end furthest from the ground, which is the oil-rich coal seam. The first injection well, the second injection well, and the discharge well all penetrate the ground and the sandstone layer in sequence and reach the oil-rich coal seam directly. The first injection well inlet is connected to the heat exchanger outlet, the second injection well inlet is connected to the turbine outlet, and the discharge well outlet is connected to the tailings assembly inlet.

[0009] Furthermore, as a preferred embodiment, the tailings assembly includes: a water tank, a second separator, a third separator, and an oil tank; The discharge well outlet is connected to the second separator, the second separator outlet is connected to the heat exchanger inlet, the cyclone inlet, the water tank inlet and the third separator inlet through a return pipe, and the third separator outlet is connected to the oil tank inlet.

[0010] Furthermore, preferably, the guiding mechanism is driven by a drive mechanism; The drive mechanism includes: a housing, a bracket, a drive component, and gears; The box body has multiple brackets on its side wall, a drive unit inside the box body, a gear at the output end of the drive unit, a transmission port at the top of the box body, and the transmission port is exposed on the side of the gear near the guide mechanism.

[0011] Furthermore, as a preferred embodiment, the guiding mechanism includes: a support member, a base ring, a rotating block, a ring block, meshing teeth, and a guide surface; The base ring is disposed on the outer wall of the flue by a plurality of the support members. The base ring has an annular groove inside. The rotating block is rotatably connected to the annular groove by a sliding ring on its outer wall. The rotating block has meshing teeth on its outer wall and an annular block on its inner wall. The end of the annular block away from the rotating block is the guide surface. The meshing teeth mesh with the gear.

[0012] Furthermore, as a preferred embodiment, the anti-sticking mechanism includes: a sliding column, a guide block, an abutting end, a spring, and an arc-shaped plate; The sliding column is slidably connected to the slide channel opened on the flue through the guide block on its outer wall. One end of the sliding column is sealed through the slide channel and extends into the flue, while the other end is sealed through the limiting member located on the outer wall of the flue and extends into the outside of the flue. The sliding column is connected to the arc-shaped plate at one end near the inside of the flue, and the other end is provided with the abutting end, which cooperates with the guide curved surface. The spring sleeved on the outer wall of the sliding column is connected between the inner wall of the slide and the guide block.

[0013] Furthermore, as a preferred embodiment, the flue has a multi-layer structure, and the bottom ends of the cyclone and the combustion chamber are respectively connected to a first water inlet pipe and a second water inlet pipe.

[0014] Furthermore, as a preferred embodiment, on the other hand, a method for using an underground coal seam heating system based on an oxygen-enriched combustion furnace, characterized by comprising the following steps: S1: A burner is provided at the top of the cyclone. The coal powder bin, the inlet pipe, the primary air pipe, the burner and the main air supply unit form a vertical coal feeding system to supply materials into the cyclone. The auxiliary air supply unit supplies tangentially entering secondary air into the cyclone through the secondary air pipe. S2: The flue gas inside the cyclone enters the combustion chamber through the flue; S3: Air enters the first separator after passing through the compressor. The first separator separates the air into oxygen and nitrogen. The oxygen acts as burnout air and flows through the burnout air duct into the burnout chamber, while the nitrogen enters the heat exchanger. S4: The steam generated by the heat from the cyclone and the combustion chamber heating the water enters the steam turbine through the first connecting pipe and the second connecting pipe to do work. The exhaust steam after doing work enters the oil-rich coal seam through the second injection well. The heat source of the heat exchanger comes from the flue gas generated in the combustion chamber. S5: The nitrogen gas located in the heat exchanger is heated, and the heated nitrogen gas enters the oil-rich coal seam through the first injection well. S6: Nitrogen and exhaust gas are coupled to heat the oil-rich coal seam. After being heated for a corresponding time, the oil-rich coal seam reaches the pyrolysis temperature, releases gaseous combustibles, and is extracted to the ground, and then enters the second separator. S7: After heat loss, nitrogen and exhaust steam, the two working fluids, enter the second separator through the discharge well. The second separator condenses the separated water vapor and stores it in the water tank. The second separator introduces the separated coal tar into the third separator and then stores it in the oil tank. The second separator reintroduces the separated nitrogen into the heat exchanger for recycling. The second separator introduces the gas produced by coal pyrolysis into the cyclone inlet to continue serving as gaseous fuel.

[0015] Compared with the prior art, the present invention provides an underground coal seam heating system and method based on an oxygen-enriched combustion furnace, which has the following beneficial effects: Advantage 1: This application retains the stable combustion, high efficiency, strong load regulation capability, and low thermal nitrogen oxide generation of the novel cyclone combustion power generation system. It introduces oxygen-enriched combustion technology to further reduce nitrogen oxide emissions, while efficiently utilizing nitrogen produced as a byproduct of oxygen production to improve the economics of oxygen-enriched combustion. By coupling nitrogen from the power generation system with turbine exhaust steam to form a multi-fluid working medium, it can both fracture oil-rich coal seams to increase their permeability and achieve efficient convective heating, promoting coal seam pyrolysis, increasing oil and gas yield, and effectively extracting oil and gas resources. Furthermore, the gas from coal seam pyrolysis can be recycled as fuel for the power generation system, achieving material and energy recycling between the two systems. Moreover, this application only requires the addition of a small number of devices to the original system, making it simple, efficient, and highly practical.

[0016] Advantage 2: The anti-sticking mechanism in this application can forcibly change the flow pattern of high-temperature flue gas containing impurities in the flue through reciprocating pushing motion. From the perspective of flow field control, it prevents the flue gas from flowing along the inner wall of the flue. Compared with conventional single-layer flue or traditional flue structures with guide plates fixed on the inner wall, it effectively solves the structural damage problems such as inner wall erosion and wear and high-temperature chemical corrosion caused by long-term flow of high-temperature flue gas containing impurities along the wall. It greatly improves the structural durability of the flue and reduces equipment operation and maintenance costs. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of an underground coal seam heating system based on an oxygen-enriched combustion furnace. Figure 2 This is a schematic diagram of the cyclone and combustion chamber structure of an underground coal seam heating system based on an oxygen-enriched combustion furnace; Figure 3 This is a schematic diagram of the drive mechanism and guide mechanism of an underground coal seam heating system based on an oxygen-enriched combustion furnace; Figure 4 A schematic diagram of the guiding mechanism structure of an underground coal seam heating system based on an oxygen-enriched combustion furnace; Figure 5 A schematic diagram of an anti-sticking mechanism for an underground coal seam heating system based on an oxygen-enriched combustion furnace. Figure 1 ; Figure 6 A schematic diagram of an anti-sticking mechanism for an underground coal seam heating system based on an oxygen-enriched combustion furnace. Figure 2 ; Figure 7 A schematic diagram of a guide surface structure for an underground coal seam heating system based on an oxygen-enriched combustion furnace. Figure 1 ; Figure 8 A schematic diagram of a guide surface structure for an underground coal seam heating system based on an oxygen-enriched combustion furnace. Figure 2 ; Figure 9 This is a schematic diagram of the flue structure of an underground coal seam heating system based on an oxygen-enriched combustion furnace; In the diagram: 1. Cyclone separator; 2. Combustion chamber; 3. Pulverized coal silo; 4. Steam turbine; 5. Compressor; 6. First separator; 7. Heat exchanger; 8. Oil-rich coal seam; 9. Water tank; 10. Second separator; 11. Third separator; 12. Sandstone layer; 13. Oil tank; 14. Flue; 141. Slide rail; 142. Protective layer; 143. Buffer layer; 144. Heat-resistant layer; 15. Inlet pipe; 16. Primary air duct; 17. Secondary air duct; 18. First connecting pipe; 19. Second connecting pipe 20. Pipe; 21. Connecting pipe; 22. Burnout duct; 22. Drive mechanism; 221. Bracket; 222. Drive component; 223. Gear; 23. Guide mechanism; 231. Support component; 232. Base ring; 233. Rotating block; 234. Ring block; 235. Meshing teeth; 236. Guide surface; 24. Anti-sticking mechanism; 241. Sliding column; 242. Guide block; 243. Abutting end; 244. Spring; 245. Arc plate; 25. First water inlet pipe; 26. Second water inlet pipe. Detailed Implementation

[0018] Please see Figures 1-9 The present invention provides an underground coal seam heating system based on an oxygen-enriched combustion furnace, comprising: a cyclone 1, a combustion chamber 2, a flue 14, a pulverized coal silo 3, a steam turbine 4, a heat exchanger 7, a coal seam group, and a tailings treatment component. The cyclone 1 inlet is connected to the pulverized coal silo 3 and the main air supply unit through the inlet pipe 15 and the primary air pipe 16 respectively. The cyclone 1 outlet is connected to the inlet of the combustion chamber 2 through the flue 14. The combustion chamber 2 outlet is connected to the inlet of the heat exchanger 7 through the connecting pipe 20. The cyclone 1 and the combustion chamber 2 side walls are connected to the inlet of the steam turbine 4 through the first connecting pipe 18 and the second connecting pipe 19 respectively. The outlet of heat exchanger 7 and the outlet of steam turbine 4 are both connected to the inlet of coal seam group through transition pipes. The outlet of coal seam group is connected to the inlet of tailings treatment component. The outlet of tailings treatment component is connected to the inlet of heat exchanger 7 and the inlet of cyclone 1 through reflux pipe. The flue 14 is equipped with a guide mechanism 23 and multiple circumferentially arranged anti-sticking mechanisms 24.

[0019] In this embodiment, please refer to Figure 1 As shown, heat exchanger 7 is a shell-and-shell type, which can adapt to the high-load heat exchange requirements of this system. It has high heat exchange efficiency, strong structural rigidity, and can withstand the erosion of high-temperature media, realizing the efficient transfer of heat energy from high-temperature flue gas to nitrogen. It can rapidly heat nitrogen to the target process temperature (about 550℃), meeting the working fluid temperature requirements for heating the oil-rich coal seam 8. At the same time, the modular structure of heat exchanger 7 is adapted to the on-site installation and subsequent maintenance requirements of the system, ensuring the process compatibility and operational stability of the heat exchange link with the overall system.

[0020] Furthermore, the side wall of the cyclone 1 is connected to a plurality of equidistant and tangentially arranged secondary air ducts 17. The ends of the plurality of secondary air ducts 17 away from the cyclone 1 are connected to the auxiliary air supply unit. The side wall of the combustion chamber 2 away from the second connecting pipe 19 is connected to the first outlet of the first separator 6 through the combustion air duct 21. The second outlet of the first separator 6 is connected to the inlet of the heat exchanger 7. The inlet of the first separator 6 is connected to the compressor 5.

[0021] In this embodiment, please refer to Figure 1 As shown, the first separator 6 is an air separator, which integrates air compression, purification, and distillation modules. It can efficiently separate the components of the raw air after it has been pressurized by the compressor 5, accurately extracting high-purity oxygen and nitrogen, thus meeting the dual-media process requirements of this system. The process parameters of the first separator 6 are linked and matched with the overall system load, and the separation efficiency can be dynamically adjusted according to specific needs. It features high separation accuracy, strong adaptability to operating conditions, and high operational stability, enabling continuous and large-scale production of oxygen and nitrogen, and providing a stable medium guarantee for subsequent operation.

[0022] Furthermore, the coal seam group includes: sandstone layer 12, oil-rich coal seam 8, first injection well, second injection well, and discharge well; Among them, the sandstone layer 12 is located at the end away from the ground, which is the oil-rich coal seam 8. The first injection well, the second injection well, and the discharge well all penetrate the ground and the sandstone layer 12 in sequence and reach the oil-rich coal seam 8 directly. The inlet of the first injection well is connected to the outlet of heat exchanger 7, the inlet of the second injection well is connected to the outlet of turbine 4, and the outlet of the discharge well is connected to the inlet of the tailings treatment component.

[0023] Furthermore, the tailings assembly includes: a water tank 9, a second separator 10, a third separator 11, and an oil tank 13; The outlet of the discharge well is connected to the second separator 10. The outlet of the second separator 10 is connected to the inlet of the heat exchanger 7, the inlet of the cyclone 1, the inlet of the water tank 9 and the inlet of the third separator 11 through the return pipe. The outlet of the third separator 11 is connected to the inlet of the oil tank 13.

[0024] In this embodiment, please refer to Figure 1As shown, the second separator 10 is a three-phase condenser separator, and the third separator 11 is an oil purification separator. The second separator 10 integrates condensation and gas-liquid-solid three-phase separation functions, enabling efficient separation of oil-gas mixtures, unreacted fluid working fluids, and small amounts of solid coal particles. Temperature and pressure control achieves gaseous hydrocarbons and liquid oil-water separation, while retaining solid impurities, completing the initial classification of the mixture and laying the foundation for subsequent purification. The third separator 11 employs a coupled process of precision filtration and component distillation to deeply purify the oil phase product after initial separation, effectively removing moisture, light hydrocarbon impurities, and trace solid residues, and precisely extracting high-purity coal tar and other target oil and gas products. The series arrangement of the second separator 10 and the third separator 11 forms a stepped separation process of initial separation and deep purification, achieving high separation accuracy and high processing efficiency.

[0025] Furthermore, the guide mechanism 23 is driven by the drive mechanism 22; The drive mechanism 22 includes: a housing, a bracket 221, a drive component 222, and a gear 223; The box has multiple brackets 221 on its side wall, a drive component 222 inside the box, a gear 223 at the output end of the drive component 222, and a transmission port at the top of the box. The transmission port is exposed on the side of the gear 223 near the guide mechanism 23.

[0026] In this embodiment, please refer to Figure 3 As shown, the bracket 221, serving as the fundamental load-bearing component of the drive mechanism 22, adopts a rigid structural design and is reliably connected to the mounting foundation. It provides stable support and positioning for the drive mechanism 22, effectively suppressing vibrations, swaying, and other unstable phenomena generated during power output and operation. This ensures precise transmission of drive actions and stable mechanism operation, laying a structural foundation for the reliable operation of the subsequent guide mechanism 23. The drive component 222 is housed within the housing. A commonly available motor with rotational drive function can be used for the drive component 222, or other motors, depending on actual requirements. The output end of the drive component 222 achieves coaxial rigid transmission with the gear 223. Its own rotation drives the gear 223 to rotate synchronously, thereby providing a power source for the movement of the guide mechanism 23 and realizing drive control of the guide mechanism 23. It should be noted that the upper tooth segment of gear 223 extends out of the transmission port opened at the top of the housing, exposing the meshing tooth surface of gear 223. This ensures that it meshes with the guide mechanism 23, ensuring that power can be efficiently and losslessly transmitted from the drive mechanism 22 to the guide mechanism 23, thus guaranteeing the smoothness of the entire transmission chain and the stability of the drive operation.

[0027] Furthermore, the guiding mechanism 23 includes: a support member 231, a base ring 232, a rotating block 233, a ring block 234, meshing teeth 235, and a guide surface 236; The base ring 232 is mounted on the outer wall of the flue 14 via multiple support members 231. An annular groove is provided inside the base ring 232. The rotating block 233 is rotatably connected to the annular groove via a sliding ring on its outer wall. The outer wall of the rotating block 233 is provided with meshing teeth 235. The inner wall of the rotating block 233 is provided with an annular block 234. The end of the annular block 234 away from the rotating block 233 is a guide curved surface 236. The meshing tooth 235 meshes with the gear 223.

[0028] In this embodiment, please refer to Figure 4 As shown, the gear 223 in the drive mechanism 22 meshes with the meshing teeth 235 of the guide mechanism 23. When the drive component 222 starts and outputs rotational power, it drives the gear 223 to rotate synchronously. Through the meshing transmission relationship between the gear 223 and the meshing teeth 235, the rotational power is efficiently transmitted to the rotating block 233, driving the rotating block 233 to rotate synchronously with the gear 223. During the rotation, the rotating block 233, relying on the precise guiding fit between itself and the slip ring and slip groove of the matching structure, forms a circumferential rotation limit guide constraint, effectively offsetting the radial offset during the rotation process, ensuring that the rotating block 233 achieves long-term stable rotational movement. At the same time, the ring block 234 fixed on the inner wall of the rotating block 233 rotates synchronously with the rotating block 233, thereby driving the integrated guide surface 236 on the ring block 234 to rotate synchronously, ensuring that the motion trajectory of the guide surface 236 is precise and controllable.

[0029] It should be noted that the rotating block 233 is assembled into the inner cavity of the base ring 232 by a rotating connection, and the two form a coaxial rotating fit structure. The base ring 232 is a symmetrical rigid structure design. Both ends of the base ring 232 are fixedly connected to the outer wall of the flue 14 by multiple sets of support members 231. The multiple sets of support members 231 on each side are evenly distributed in a circular pattern along the circumference of the base ring 232. This arrangement can make the support force evenly distributed along the circumference of the base ring 232, which greatly improves the structural stability of the connection between the base ring 232 and the flue 14, provides a stable rotating support foundation for the rotating block 233, eliminates the shaking and offset problems of the rotating block 233 during long-term rotation from the structural level, and ensures the stability and durability of the overall operation of the guide mechanism 23.

[0030] Furthermore, the anti-sticking mechanism 24 includes: a sliding column 241, a guide block 242, an abutting end 243, a spring 244, and an arc-shaped plate 245; Among them, the sliding column 241 is slidably connected to the slide 141 opened on the flue 14 through the guide block 242 on its outer wall. One end of the sliding column 241 is sealed and passes through the slide 141 and extends into the flue 14, while the other end is sealed and passes through the limiting member located on the outer wall of the flue 14 and extends into the outside of the flue 14. One end of the sliding column 241 near the inside of the flue 14 is connected to an arc plate 245, and the other end is provided with an abutment end 243. The abutment end 243 cooperates with the guide curved surface 236. A spring 244 sleeved on the outer wall of the sliding column 241 is connected between the inner wall of the slide 141 and the guide block 242.

[0031] In this embodiment, please refer to Figure 3 , Figure 4 , Figure 5 and Figure 6 As shown, when the ring block 234 rotates synchronously with the rotating block 233, the guide surface 236 on its outer wall undergoes circumferential rotation (e.g., Figure 5 As shown by the solid arrow in the middle, under the rotation of the guide surface 236, the contact ends 243 of the multiple sets of anti-sticking mechanisms 24 arranged circumferentially along the flue 14 are pushed by the contour of the guide surface 236, and simultaneously drive the sliding column 241 of each anti-sticking mechanism 24 along the curve. Figure 5 The dashed arrow indicates that the mechanism 24 moves in a reciprocating linear motion to achieve the linkage action of the anti-sticking mechanism 24.

[0032] For a preferred embodiment, please refer to the following: Figure 7 As shown, in the first embodiment of this application, the guide surface 236 is an irregular curved surface structure. Due to the pushing effect of the irregular changes in the contour of the guide surface 236, the reciprocating stroke and speed of the multiple sets of sliding columns 241 arranged in the circumferential direction are irregularly and differentially distributed, such as... Figure 7 The marked points are the characteristic positions of the arc-shaped plates 245 of each anti-sticking mechanism 24 after they extend. Based on this motion characteristic, multiple sets of circumferentially arranged arc-shaped plates 245 can create irregular disturbances to the high-temperature flue gas containing impurities flowing along the inner wall of the flue 14, forcing the flue gas to detach from the inner wall of the flue 14. This avoids structural damage such as erosion and high-temperature corrosion of the inner wall of the flue 14 caused by long-term flow of high-temperature flue gas containing impurities, effectively reducing the later maintenance cost of the equipment and ensuring the stable operation of subsequent system processes.

[0033] For a preferred embodiment, please refer to the following: Figure 8 As shown, in the second embodiment of this application, to meet the process requirement that the high-temperature flue gas containing impurities needs to enter the combustion chamber 2 in a stable flow state, the guide surface 236 is set as a regular curved surface structure. Due to the uniform pushing action of the contour of the guide surface 236, the reciprocating stroke and speed of all circumferential sliding columns 241 remain consistent, such as... Figure 8 The marked points are the characteristic positions of each arc plate 245 after it extends. In other words, multiple sets of arc plates 245 can form a regular and synchronous pushing and disturbing effect on the flue gas attached to the inner wall of the flue 14. While realizing the flue gas detachment from the wall, the flue gas flow field can be normalized and controlled to ensure that the high-temperature flue gas containing impurities enters the combustion chamber 2 with a stable flow state and flow rate, which is suitable for the oxygen-enriched combustion process requirements in the combustion chamber 2.

[0034] In this embodiment, when the contact end 243 of the anti-sticking mechanism 24 abuts against the protruding section of the guide curved surface 236, the contact end 243 is subjected to a pushing force, which drives the sliding column 241, the guide block 242, and the arc plate 245 along the direction of the anti-sticking mechanism 243. Figure 6 The mechanism moves vertically downwards synchronously, compressing the spring 244. When the contact end 243 rotates with the guide surface 236 and disengages from its protruding section, the spring 244 releases its elastic potential energy, causing the sliding column 241, guide block 242, and arc plate 245 to perform a reset movement along the slide 141. The limiting component configured on the flue 14 can limit the guide block 242 during the reset process, effectively preventing the guide block 242 from disengaging from the slide 141 due to excessive reset stroke, thus ensuring the structural reliability and motion accuracy of the anti-sticking mechanism 24's reciprocating motion.

[0035] Furthermore, the flue 14 has a multi-layer structure, and the bottom ends of the cyclone 1 and the combustion chamber 2 are respectively connected to the first water inlet pipe 25 and the second water inlet pipe 26.

[0036] In this embodiment, please refer to Figure 9 As shown, the flue 14 in this application has a multi-layer structure, with an outer protective layer 142, a middle buffer layer 143, and an inner heat-resistant layer 144. The structural strength of the multi-layer structure of the flue 14 can support the normal operation of multiple anti-sticking mechanisms 24.

[0037] As a preferred embodiment, the anti-sticking mechanism 24 in this application can forcibly change the flow pattern of the high-temperature flue gas containing impurities in the flue 14 through reciprocating pushing action, thereby preventing the flue gas from flowing along the inner wall of the flue 14 from the perspective of flow field control. Compared with the conventional structure of a single layer or a guide plate fixed on the inner wall, it effectively solves the structural damage problems such as inner wall erosion and wear and high-temperature chemical corrosion caused by long-term wall-sticking flow of high-temperature flue gas containing impurities, greatly improves the structural durability of the flue 14, and reduces equipment operation and maintenance costs.

[0038] It should be noted that this application can adjust the number and spacing of the drive mechanism 22, guide mechanism 23 and anti-sticking mechanism 24 according to the actual axial length of the flue 14, so as to achieve full coverage control of the flow field of the entire flow channel of the flue 14, ensuring that the high temperature flue gas containing impurities maintains a non-wall-sticking flow state throughout the entire flow process in the flue 14, and fundamentally eliminates the hidden dangers of wall-sticking corrosion and wear in different sections of the flue 14.

[0039] In this embodiment, the first water inlet pipe 25 and the second water inlet pipe 26 provide the water required for operation to the cyclone 1 and the combustion chamber 2, respectively. It should be noted that the first water inlet pipe 25 and the second water inlet pipe 26 are... Figure 2 Not shown in the image.

[0040] Furthermore, a method for using an underground coal seam heating system based on an oxygen-enriched combustion furnace includes the following steps: S1: A burner is installed at the top of the cyclone 1 for igniting the cyclone 1. The coal powder bin 3, the inlet pipe 15, the primary air pipe 16, the burner and the main air supply unit form a vertical coal feeding system to supply materials to the cyclone 1. The auxiliary air supply unit supplies tangentially entering secondary air to the cyclone 1 through the secondary air pipe 17. S2: The flue gas in the cyclone 1 enters the combustion chamber 2 through the flue 14; S3: Air enters the first separator 6 after passing through the compressor 5. The first separator 6 performs a separation operation on the air, separating it into high-concentration oxygen and nitrogen. The high-concentration oxygen acts as the burnout air and flows through the burnout air duct 21 into the burnout chamber 2, while the nitrogen enters the heat exchanger 7. S4: The steam generated by heating water from the heat of the cyclone 1 and the combustion chamber 2 enters the steam turbine 4 through the first connecting pipe 18 and the second connecting pipe 19 to do work. The exhaust steam after doing work enters the oil-rich coal seam 8 through the second injection well. The heat source of the heat exchanger 7 comes from the flue gas generated by the combustion chamber 2. S5: The nitrogen gas located in the heat exchanger 7 is heated, and the heated nitrogen gas enters the oil-rich coal seam 8 through the first injection well; S6: Nitrogen and exhaust steam are coupled to heat the oil-rich coal seam 8. After being heated for a corresponding time, the oil-rich coal seam 8 reaches the pyrolysis temperature, releases gaseous combustibles, and is extracted to the ground, and then enters the second separator 10. S7: After heat loss, nitrogen and exhaust steam, the two working fluids, enter the second separator 10 through the discharge well. The second separator 10 condenses the separated water vapor and stores it in the water tank 9. The second separator 10 introduces the separated coal tar into the third separator 11 and then stores it in the oil tank 13. The second separator 10 reintroduces the separated nitrogen into the heat exchanger 7 for recycling. The second separator 10 introduces the gas generated from the pyrolysis of coal into the inlet of the cyclone 1 to continue to serve as gaseous fuel.

[0041] As a preferred embodiment, this application, while retaining the stable combustion, high efficiency, strong load regulation capability, and low thermal nitrogen oxide generation of the novel cyclone combustion power generation system, introduces oxygen-enriched combustion technology to further reduce nitrogen oxide emissions. Simultaneously, it efficiently utilizes nitrogen produced as a byproduct of oxygen production to improve the economics of oxygen-enriched combustion. By coupling nitrogen from the power generation system with the exhaust steam from the turbine 4 to form a multi-fluid working medium, it can both fracture the oil-rich coal seam 8 to increase its permeability and achieve efficient convective heating, promoting coal seam pyrolysis, increasing oil and gas yield, and effectively extracting oil and gas resources. Furthermore, the gas from coal seam pyrolysis can be recycled as fuel for the power generation system, achieving material and energy recycling between the two systems. Moreover, this application only requires the addition of a small number of devices to the original system, making it simple, efficient, and highly practical.

[0042] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. An underground coal seam heating system based on an oxygen-enriched combustion furnace, characterized in that: include: Cyclone (1), combustion chamber (2), flue (14), pulverized coal silo (3), steam turbine (4), heat exchanger (7), coal seam group and tailings treatment components; The inlet of the cyclone (1) is connected to the pulverized coal silo (3) and the main air supply unit through the inlet pipe (15) and the primary air pipe (16), respectively. The outlet of the cyclone (1) is connected to the inlet of the combustion chamber (2) through the flue (14). The outlet of the combustion chamber (2) is connected to the inlet of the heat exchanger (7) through the connecting pipe (20). The side walls of the cyclone (1) and the combustion chamber (2) are connected to the inlet of the steam turbine (4) through the first connecting pipe (18) and the second connecting pipe (19), respectively. The outlet of the heat exchanger (7) and the outlet of the steam turbine (4) are both connected to the inlet of the coal seam group through a transition pipe. The outlet of the coal seam group is connected to the inlet of the tailings treatment component. The outlet of the tailings treatment component is connected to the inlet of the heat exchanger (7) and the inlet of the cyclone (1) through a return pipe. The flue (14) is provided with a guide mechanism (23) and multiple anti-sticking mechanisms (24) arranged in a circle. The guiding mechanism (23) includes: a support (231), a base ring (232), a rotating block (233), a ring block (234), meshing teeth (235), and a guide surface (236); The base ring (232) is disposed on the outer wall of the flue (14) by a plurality of the support members (231). The base ring (232) has an annular groove inside. The rotating block (233) is rotatably connected to the annular groove by a sliding ring on its outer wall. The rotating block (233) has meshing teeth (235) on its outer wall and an annular block (234) on its inner wall. The end of the annular block (234) away from the rotating block (233) is the guide surface (236). The anti-sticking mechanism (24) includes: a sliding column (241), a guide block (242), an abutting end (243), a spring (244), and an arc plate (245). The sliding column (241) is slidably connected to the slide (141) opened on the flue (14) via the guide block (242) on its outer wall. One end of the sliding column (241) is sealed through the slide (141) and extends into the flue (14), while the other end is sealed through the limiting member located on the outer wall of the flue (14) and extends into the outside of the flue (14). The sliding column (241) is connected to the arc plate (245) at one end near the inside of the flue (14), and the other end is provided with the abutment end (243). The abutment end (243) cooperates with the guide surface (236). The inner wall of the slide (141) and the guide block (242) are connected by the spring (244) sleeved on the outer wall of the sliding column (241).

2. The underground coal seam heating system based on an oxygen-enriched combustion furnace according to claim 1, characterized in that: The side wall of the cyclone (1) is connected to a plurality of equidistant and tangentially arranged secondary air ducts (17). The ends of the plurality of secondary air ducts (17) away from the cyclone (1) are connected to the auxiliary air supply unit. The side wall of the combustion chamber (2) away from the second connecting pipe (19) is connected to the first outlet of the first separator (6) through the combustion air duct (21). The second outlet of the first separator (6) is connected to the inlet of the heat exchanger (7). The inlet of the first separator (6) is connected to the compressor (5).

3. The underground coal seam heating system based on an oxygen-enriched combustion furnace according to claim 2, characterized in that: The coal seam group includes: a sandstone layer (12), an oil-rich coal seam (8), a first injection well, a second injection well, and a discharge well; Among them, the sandstone layer (12) is located at the end away from the ground, which is the oil-rich coal seam (8). The first injection well, the second injection well and the discharge well all penetrate the ground and the sandstone layer (12) in sequence and reach the oil-rich coal seam (8). The first injection well inlet is connected to the outlet of the heat exchanger (7), the second injection well inlet is connected to the outlet of the steam turbine (4), and the discharge well outlet is connected to the inlet of the tailings assembly.

4. The underground coal seam heating system based on an oxygen-enriched combustion furnace according to claim 3, characterized in that: The tailings assembly includes: a water tank (9), a second separator (10), a third separator (11), and an oil tank (13). The outlet of the discharge well is connected to the second separator (10), the outlet of the second separator (10) is connected to the inlet of the heat exchanger (7), the inlet of the cyclone (1), the inlet of the water tank (9) and the inlet of the third separator (11) through the return pipe, and the outlet of the third separator (11) is connected to the inlet of the oil tank (13).

5. The underground coal seam heating system based on an oxygen-enriched combustion furnace according to claim 1, characterized in that: The guiding mechanism (23) is driven by the driving mechanism (22); The drive mechanism (22) includes: a housing, a bracket (221), a drive component (222), and a gear (223); The box body has multiple brackets (221) on its side wall, a drive unit (222) inside the box body, a gear (223) at the output end of the drive unit (222), a transmission port at the top of the box body, and the transmission port is exposed on the side of the gear (223) near the guide mechanism (23). The meshing teeth (235) mesh with the gear (223).

6. The underground coal seam heating system based on an oxygen-enriched combustion furnace according to claim 1, characterized in that: The flue (14) has a multi-layer structure, and the bottom ends of the cyclone (1) and the combustion chamber (2) are respectively connected to the first water inlet pipe (25) and the second water inlet pipe (26).

7. A method of using an underground coal seam heating system based on an oxygen-enriched combustion furnace, based on the underground coal seam heating system based on an oxygen-enriched combustion furnace as described in claim 4, characterized in that: It includes the following steps: S1: A burner is provided at the top of the cyclone (1). The coal powder bin (3), the inlet pipe (15), the primary air pipe (16), the burner and the main air supply device form a vertical coal feeding system to supply materials to the cyclone (1). The auxiliary air supply device supplies tangentially entering secondary air to the cyclone (1) through the secondary air pipe (17). S2: The flue gas in the cyclone (1) enters the combustion chamber (2) through the flue (14); S3: Air enters the first separator (6) through the compressor (5), and the first separator (6) performs a separation operation on the air, separating it into oxygen and nitrogen. The oxygen acts as burnout air and flows through the burnout air duct (21) into the burnout chamber (2), while the nitrogen enters the heat exchanger (7). S4: The steam generated by the heat from the cyclone (1) and the combustion chamber (2) heating the water enters the steam turbine (4) through the first connecting pipe (18) and the second connecting pipe (19) to do work. The exhaust steam after doing work enters the oil-rich coal seam (8) through the second injection well. The heat source of the heat exchanger (7) comes from the flue gas generated by the combustion chamber (2). S5: The nitrogen gas located in the heat exchanger (7) is heated, and the heated nitrogen gas enters the oil-rich coal seam (8) through the first injection well. S6: Nitrogen and exhaust gas are coupled to heat the oil-rich coal seam (8). After the oil-rich coal seam (8) is continuously heated for a corresponding time, it reaches the pyrolysis temperature, decomposes the gaseous combustibles and extracts them to the ground, and then enters the second separator (10). S7: After heat loss, nitrogen and exhaust steam, the two working fluids, enter the second separator (10) through the discharge well. The second separator (10) condenses the separated water vapor and stores it in the water tank (9). The second separator (10) introduces the separated coal tar into the third separator (11) and then stores it in the oil tank (13). The second separator (10) reintroduces the separated nitrogen into the heat exchanger (7) for recycling. The second separator (10) introduces the gas generated by the pyrolysis of the separated coal into the inlet of the cyclone (1) to continue to serve as gaseous fuel.

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