A ground long-hole coal body internal combustion fluidized mining device and working method

Abstract

The present invention discloses a surface long-bore coal body internal combustion fluidized mining device and working method, relating to the technical field of coalbed methane mining and gas extraction. It comprises a combustion support system and a drainage system; it comprises an oxidizer tank, a reductant tank, and an igniter, as well as a combustion pipe and a drainage pipe that enter the coal seam borehole through the wellbore, with a flame head provided at the end of the combustion pipe; the drainage system comprises a heat exchanger and a water-gas separator connected to each other by pipelines, a valve provided on the pipeline, a refrigerant inlet and a refrigerant outlet provided on the heat exchanger, and an oil pump connected to the oil pump through a mixing pipe. The oil pump is connected to the drainage pipe, and the gas and water extracted by the oil pump enter the heat exchanger through the mixing pipe. The system utilizes the oxidizer and reductant to react and release heat in the coal seam borehole, igniting the coal in the coal seam, achieving continuous, stable, and controlled combustion of a portion of the coal body inside the borehole, thereby changing the underground mining mode of coal mines and achieving safe and green mining without the removal of waste rock from the mine and the need for personnel to go down the mine, which is of great significance.

Description

Technical Field

[0001] The present invention relates to the technical field of coal mine gas extraction, in particular to a ground long-hole coal body internal combustion fluidization mining device and a working method. Background Art

[0002] In recent years, as my country's coal mining has gradually entered a phase of deep mining, problems such as high geothermal temperatures, high ground stress, and difficulty in gas extraction have become particularly prominent, increasing risks and making underground operations increasingly unsuitable for human labor. Currently, conventional coal mining involves open-pit and underground mining. Open-pit mining is only suitable for shallow coal seams. Deep coal seams are currently mined only to depths of 1,500 meters, while oil mining can reach depths of over 9,000 meters. The key difference between the two is that coal is solid, while oil is liquid. Therefore, converting the coal seam from a solid state to a fluid underground and then pumping it out to the surface avoids large-scale manual mining, eliminates the various risks posed to personnel underground, reduces the emission of waste rock during mining, improves coal mining efficiency, and protects the environment. The implementation of this technology will have a revolutionary impact on coal mining. Summary of the Invention

[0003] Technical problem: In order to address the shortcomings of existing technologies, a simple, reliable, and easy-to-operate fluidized mining device and working method for internal combustion of coal bodies in long-bore holes on the ground are provided, which can effectively fluidize the coal body in the borehole and convert the solid into gas or liquid, thereby directly extracting beneficial gas or liquid from the ground borehole and realizing fluidized mining. This device overcomes the various risks faced by people going down the well during underground mining, the complexity of the underground mining system, and the need to transport waste rock to the surface.

[0004] Technical solution: The present invention provides a ground long-hole coal body internal combustion fluidized mining device, including a combustion support system and a drainage system;

[0005] The combustion support system includes an oxidizer tank for filling an oxidizer, a reducer tank for filling a reducer, and an igniter arranged on the surface, as well as a combustion tube and a drainage tube that enter the coal seam drill hole through the wellbore, and a flame head is provided at the end of the combustion tube; the combustion tube includes an electric cable wrapped in a heat-insulating sleeve, an oxidizer tube, a reducer tube, and a steel wire rope, the electric cable includes a temperature-sensing wire and an ignition wire, the oxidizer tank and the reducer tank are connected to the flame head through the oxidizer tube and the reducer tube respectively, the end of the flame head is provided with a nozzle, a temperature probe and an ignition needle are provided inside, and the ignition needle and the temperature probe are connected to the igniter through the ignition wire and the temperature-sensing wire;

[0006] The drainage and production system includes a heat exchanger and a water-gas separator connected to each other by pipelines. Valves are provided on the pipelines. A refrigerant inlet and a refrigerant outlet are provided on the heat exchanger. The heat exchanger is connected to an oil pump through a mixing pipe. The oil pump is connected to the drainage and production pipe. A screen pipe is provided at the end of the drainage and production pipe. The gas and water extracted by the oil pump through the drainage and production pipe enter the heat exchanger through the mixing pipe, and then enter the water-gas separator to separate the water and the mixed gas, and the water is discharged from the cold water outlet provided thereon, and the mixed gas is discharged from the mixed gas outlet provided thereon.

[0007] Furthermore, the production system also includes a winch installed on the surface for winding the combustion pipe. The winch changes direction through a steering seat. The winch is equipped with a steering seat at the wellhead. The rotating shaft on the steering seat changes the drag force of the winch from the tangential direction formed by the winch and the steering seat to a vertical direction.

[0008] Furthermore, the flame spray head includes a flame spray head sleeve, and the ends of the cable, oxidizer tube, and reductant tube are all arranged in the flame spray head sleeve. The end of the flame spray head sleeve is a frustum structure, and a plurality of nozzles for expanding the flame spray range are provided on the side of the frustum.

[0009] Furthermore, the cross-sections of the oxidant tube and the reducing agent tube wrapped by the insulation sleeve of the combustion tube are symmetrically distributed on the left and right sides in the middle position of the combustion tube, the ignition wire and the temperature sensing wire are arranged side by side at the upper ends of the oxidant tube and the reducing agent tube, and the steel wire rope is located at the lower ends of the oxidant tube and the reducing agent tube.

[0010] Furthermore, a flow meter, a valve and a flame arrester are provided between the oxidizer tank and the oxidizer pipe, and a flow meter, a valve and a flame arrester are provided between the reductant tank and the reductant pipe.

[0011] A working method of a ground long-hole coal body internal combustion fluidized mining device specifically comprises the following steps:

[0012] a. Install two flame arresters to the ends of the oxidizer tube and the reductant tube respectively, install the temperature probe to the end of the temperature sensing wire, install the ignition needle to the end of the ignition wire, align the flame head sleeve with the insulation sleeve, tighten it, and install the nozzle to form the flame head; and use the combustion tube connected to the flame head as the moving end of the winch;

[0013] b. The oxidant and reducing agent pipes separated from the combustion pipe at the fixed end of the winch are connected to the flow meter, valve and flame arrester respectively, and finally connected to the oxidant tank and reducing agent tank respectively; the cables are connected to the igniter;

[0014] c. After the connection is completed, open the valves on the oxidizer pipe and the reducing agent pipe, and then turn on the igniter to perform an ignition test to confirm that the ignition is correct;

[0015] d. Use a drilling rig and drill rod to construct a long borehole from the ground into the coal seam and lower the shaft into the wellbore. The long borehole includes a vertical section and a coal seam section. The vertical section is a vertical borehole that penetrates the rock stratum to reach the coal seam, and the coal seam section is a horizontal borehole constructed in the coal seam. The angle between the vertical section and the coal seam section is less than degrees. The starting point of the coal seam section is at the lowest point and close to the floor, and the end of the coal seam section is at the highest point and close to the roof of the coal seam, so that the coal seam section forms an inclined borehole in the coal seam. The length of the coal seam section is not less than meters;

[0016] e. Install the screen pipe to the end of the drainage pipe. Connect the tail end of the drainage pipe to the pumping unit, mixing pipe, flow meter, heat exchanger, valve, and water-gas separator in sequence. Perform an airtightness test to ensure that there is no air leakage. Then, use a drill rig and drill pipe to send the combustion pipe into the long borehole to the bottom of the hole, and send the drainage pipe into the coal seam section of the long borehole.

[0017] f. Seal the wellbore at the borehole, fix the outer casing of the drainage pipe and the combustion pipe, and inject cement mortar to seal the space inside the wellbore and outside the drainage pipe and casing;

[0018] g. Start the pumping unit. If water is pumped out, drain the water first with the pumping unit. Then inject a mixed gas into the borehole in the ratio required for complete combustion of the oxidant and the reductant. Use the igniter to control the ignition needle in the nozzle head to continuously ignite until the temperature transmitted by the temperature probe on the igniter stabilizes above 3000 degrees, indicating that combustion is continuing inside the long borehole.

[0019] h. Detect the gas composition separated from the mixed gas outlet of the water-gas separator after being pumped out by the pumping unit. If the concentration of combustible methane, H2 or CO continues to rise, gradually reduce the supply of reducing agent and continue to supply oxidant. Use temperature probes to monitor in real time to ensure that combustion is maintained inside the borehole.

[0020] i. The consumption of coal seams during the combustion process is calculated based on the gas flow rate discharged from the mixed gas outlet, thereby determining the dragging speed of the combustion tube and the rotation speed of the winch. The burner head is then maintained burning the long borehole coal seam section. The winch is generally used to drag the combustion tube toward the vertical section until the coal seams surrounding the coal seam section are completely burned. This ensures continuous, stable, and controlled combustion of the coal body inside the borehole, achieving safe and green mining without the removal of waste rock or personnel entering the mine.

[0021] j. When the burner head is dragged to the screen tube position, stop the supply of oxidant and reducing agent and continue extraction. When the temperature displayed on the igniter is below ℃, it indicates that the flame inside the long borehole has been extinguished. At this time, if the concentration of combustible gas in the extracted mixed gas, including methane, H, CO or other alkane gases such as ethane, is higher than %, continue extraction. If it is lower than %, stop extraction.

[0022] K. Continue drilling horizontal branch wells on the basis of the wellbore to expand the coverage of the long borehole. After the construction is completed, repeat steps d to j until the designed gasification area of the coal seam is fully covered and coal seam combustion gas production is completed;

[0023] l. Use the drainage pipe to inject water into the coal seam to ensure that all flames in the goaf are extinguished after combustion; remove the combustion pipe and seal the wellbore.

[0024] Furthermore, the long borehole is mostly vertical in the rock formation, then smoothly reaches the bottom plate in the coal seam, and further forms a slope of .%-% in the coal seam.

[0025] Furthermore, the drainage pipes and combustion pipes located inside the wellbore are sealed at the wellhead for no less than m.

[0026] Furthermore, the coverage of long boreholes can be expanded through branch wells by arranging multiple parallel long boreholes in the coal seam through a vertical section; or by arranging fishbone-shaped branch boreholes or tree-branch-shaped branch boreholes on a single long borehole.

[0027] Furthermore, the scope of coverage of long boreholes can be expanded by constructing multiple horizontally arranged parallel boreholes in parallel during the construction of long boreholes, and at the same time providing a combustion tube in each parallel borehole. By increasing the spacing between horizontal holes, increasing the speed of dragging the combustion tube and other parameters, the consumption of coal per unit length of the coal seam is reduced, thereby forming multiple rows of enlarged boreholes, thereby achieving pressure relief and permeability enhancement of the coal seam.

[0028] Beneficial Effects: By employing the above-mentioned technical solution, the present invention enables fluidized mining of the coal mass around the borehole, reducing the various risks associated with manual mining. Furthermore, it can mine various coal seams, including extremely thin ones, and can mine coal seams over 200 meters deep. This technology combines coal mining and coal gasification, achieving the goal of direct extraction of useful gas without human intervention underground and without coal and gangue aboveground, while significantly reducing coal mining costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic structural diagram of the surface long-hole coal body internal combustion fluidized mining device of the present invention;

[0030] Figure 2 It is a schematic diagram of the flame head of the present invention;

[0031] Figure 3 It is a schematic diagram of the combustion tube of the present invention;

[0032] Figure 4 This is a schematic diagram of drilling multiple horizontal branch wells on the basis of a wellbore according to the present invention;

[0033] Figure 5It is a schematic diagram of constructing a fishbone-shaped drill hole on a long drill hole according to the present invention;

[0034] Figure 6 It is a schematic diagram of a long borehole for constructing a widened horizontal branch well according to the present invention.

[0035] In the figure: 1—wellbore, 2—drainage and production pipe, 3—combustion pipe, 4—screen pipe, 5—pumping unit, 6—mixing pipe, 7—flow meter, 8—casing, 9—heat exchanger, 10—valve, 11—refrigerant outlet, 12—water-gas separator, 13—mixed gas outlet, 14—cold water outlet, 15—steering seat, 16—winch, 17—electric cable, 18—oxidizer pipe, 19—igniter, 20—reducing agent pipe, 21—oxidizer tank, 22—flame arrester, 23—reducing agent tank, 24—flame head, 25—wire rope, 26—insulating casing, 27—rock layer, 28—coal layer, 29—ash, 30—long drill hole, 24-1—ignition wire, 24-2—temperature sensing wire, 24-3—temperature probe, 24-4—ignition needle, 24-5—nozzle, 24-6—flame head casing. DETAILED DESCRIPTION

[0036] An embodiment of the present invention will be further described below with reference to the accompanying drawings:

[0037] like Figure 1 As shown, the surface long-hole coal body internal combustion fluidized mining device of the present invention includes a combustion support system and a drainage system;

[0038] The combustion support system includes an oxidant tank 21 for filling an oxidant, a reductant tank 23 for filling a reductant and an igniter 19 arranged on the surface, and a combustion pipe 3 and a drainage pipe 3 entering the coal seam drill hole through the wellbore 1, and a flame head 24 is provided at the end of the combustion pipe 3; the combustion pipe 3 includes a cable 17 wrapped by a heat-insulating sleeve 26, an oxidant pipe 18, a reductant pipe 20 and a steel wire rope 25, the cable 17 includes a temperature-sensing wire 24-2 and an ignition wire 24-1, the oxidant tank 21 and the reductant tank 23 are connected to the flame head 24 through the oxidant pipe 18 and the reductant pipe 20 respectively, the end of the flame head 24 is provided with a nozzle 24-5, and a temperature probe 24-3 and an ignition needle 24-4 are provided inside, and the ignition needle 24-4 and the temperature probe 24-3 are connected to the igniter 19 through the ignition wire 24-1 and the temperature-sensing wire 24-2, as shown in FIG. Figure 2 As shown;

[0039] The drainage system includes a heat exchanger 9 and a water-gas separator 12 connected to each other by pipelines. A valve 10 is provided on the pipeline. A refrigerant inlet and a refrigerant outlet 11 are provided on the heat exchanger 9. The heat exchanger 9 is connected to the oil pump 5 through a mixing pipe 6. The oil pump 5 is connected to the drainage pipe 2. A screen pipe 4 is provided at the end of the drainage pipe 2. The gas and water extracted by the oil pump 5 in the drainage pipe 2 enter the heat exchanger 9 through the mixing pipe 6, and then enter the water-gas separator 12 to separate the water and the mixed gas. The water is discharged from the cold water outlet 14 provided thereon, and the mixed gas is discharged from the mixed gas outlet 13 provided thereon; the drainage system also includes a winch 16 provided on the surface for winding the combustion pipe 3. The winch 16 changes direction through the steering seat 15. The winch 16 is equipped with a steering seat 15 at the wellhead. The rotating shaft on the steering seat 15 converts the drag force of the winch 16 from the tangential direction formed by the winch 16 and the steering seat 15 to the vertical direction.

[0040] The flame head 24 includes a flame head sleeve 24-6, and the ends of the cable 17, the oxidizer tube 18, and the reducing agent tube 20 are all arranged in the flame head sleeve 24-6. The end of the flame head sleeve 24-6 is a frustum structure, and a plurality of nozzles 24-5 for expanding the flame spraying range are provided on the side of the frustum. The cross-sections of the oxidizer tube 18 and the reducing agent tube 20 wrapped by the heat-insulating sleeve 26 of the combustion tube 3 are located in the middle position of the combustion tube 3 and are symmetrically distributed on the left and right. The ignition wire 24-1 and the temperature sensing wire 24-2 are arranged side by side at the upper ends of the oxidizer tube 18 and the reducing agent tube 20, and the wire rope 25 is located at the lower ends of the oxidizer tube 18 and the reducing agent tube 20; a flow meter 7, a valve 10 and a flame arrester 22 are provided between the oxidizer tank 21 and the oxidizer tube 18, and a flow meter 7, a valve 10 and a flame arrester 22 are provided between the reducing agent tank 23 and the reducing agent tube 20.

[0041] A working method of a ground long-hole coal body internal combustion fluidized mining device specifically comprises the following steps:

[0042] a. Install two flame arresters 22 to the ends of the oxidizer tube 18 and the reductant tube 20, respectively. Install the temperature probe 24-3 to the end of the temperature sensing wire 24-2, and the ignition needle 24-4 to the end of the ignition wire 24-1. Align the flame head sleeve 24-6 with the insulation sleeve 26, tighten them, and install the nozzle 24-5 to form the flame head 24. Use the combustion tube connected to the flame head 24 as the moving end of the winch 16.

[0043] b. The oxidant pipe 18 and the reducing agent pipe 20 branching from the combustion pipe 3 at the fixed end of the hoist 16 are respectively connected to the flow meter 7, the valve 10 and the flame arrester 22, and finally connected to the oxidant tank 21 and the reducing agent tank 23 respectively; the cable 17 is connected to the igniter 19;

[0044] c. After the connection is completed, open the valves 10 on the oxidant pipe 18 and the reducing agent pipe 20, and then open the igniter 19 to perform an ignition test to confirm that the ignition is correct;

[0045] d. Using a drilling rig and drill pipe, construct a long borehole 30 from the ground into the coal seam 28 and lower the shaft 1. The long borehole 30 includes a vertical section and a coal seam section. The vertical section is a vertical borehole that penetrates the rock layer 27 and reaches the coal seam 28. The coal seam section is a horizontal borehole constructed in the coal seam 28. The angle between the vertical section and the coal seam section is less than 90 degrees. The coal seam section starts at the lowest point and is close to the floor, and ends at the highest point and is close to the roof of the coal seam 28, so that the coal seam section forms an inclined borehole in the coal seam 28. The length of the coal seam section is not less than 50 meters.

[0046] e. Install the screen tube 4 to the end of the drainage pipe 2. Connect the tail end of the drainage pipe 2 to the pumping unit 5, mixing pipe 6, flow meter 7, heat exchanger 9, valve 10, and water-gas separator 12 in sequence. Perform an airtightness test to ensure that there is no air leakage. Then, use a drill rig and drill pipe to send the combustion tube 3 into the long borehole 30 to the bottom of the hole, and send the drainage pipe 2 into the coal seam section of the long borehole 30.

[0047] f. Seal the wellbore 1 at the borehole, fix the outer casing 8 of the drainage pipe 2 and the combustion pipe 3, and inject cement mortar to seal the space inside the wellbore 1 and outside the drainage pipe 2 and the casing 8;

[0048] g. Start the pumping unit. If water is pumped out, first use the pumping unit 5 to remove the water. Then, inject a mixed gas in a ratio that allows the oxidant and the reducing agent to burn completely into the borehole. Use the igniter 19 to control the ignition needle 24-4 in the nozzle head 24 to continuously ignite until the temperature transmitted by the temperature probe 24-3 on the igniter 19 stabilizes at above 500 degrees, indicating that combustion is continuing inside the long borehole 30.

[0049] h. Detect the gas composition separated from the mixed gas outlet 13 of the water-gas separator 12 after being extracted by the pumping unit 5. If the concentration of combustible methane, H2 or CO continues to rise, gradually reduce the supply of reducing agent and continue to supply oxidant. Use the temperature probe 24-3 to monitor in real time to ensure that combustion is maintained inside the borehole;

[0050] i. The consumption of the coal seam 28 during the combustion process is calculated based on the gas flow rate discharged from the mixed gas outlet 13, thereby determining the dragging speed of the combustion tube 3 and the rotation speed of the winch. Then, while the flame head 24 is maintained to burn the coal seam section of the long borehole 30, the winch 16 is generally used to drag the combustion tube 3 toward the vertical section until the coal seam surrounding the coal seam section is completely burned, thereby achieving continuous, stable and controlled combustion of the coal body inside the borehole, and realizing safe and green mining without the removal of waste rock and the need for personnel to go down the mine;

[0051] j. When the burner head 24 is dragged to the position of the screen tube 4, the supply of the oxidant and the reducing agent is stopped and extraction is continued. When the temperature displayed on the igniter 19 is below 100°C, it indicates that the flame inside the long borehole 30 has been extinguished. At this time, if the concentration of combustible gases in the extracted mixed gas, including methane, H2, CO or other alkane gases, is higher than 30%, extraction is continued; if it is lower than 30%, extraction is stopped.

[0052] K. Continue drilling horizontal branch wells on the basis of the wellbore 1 to expand the coverage of the long borehole 30. After the construction is completed, repeat steps d to j until the designed gasification area of the coal seam is fully covered, completing coal seam combustion gas production;

[0053] 1. Use the drainage pipe 2 to inject water into the coal seam 28 to ensure that the flames in the goaf after combustion are completely extinguished; remove the combustion pipe 3 and seal the wellbore.

[0054] The long borehole 30 is mostly vertical in the rock layer 27, then smoothly reaches the bottom plate in the coal seam 28, and further forms a slope of 0.5%-5% in the coal seam; the drainage pipe 2 and combustion pipe 3 located inside the wellbore 1 are sealed for no less than 3m at the wellhead.

[0055] like Figure 4 、 Figure 5 and Figure 6 As shown, the scope of coverage of the extended long borehole 30 through the branch well includes: arranging multiple parallel long boreholes 30 in the coal seam 28 through a vertical section; or arranging fishbone-shaped branch boreholes or tree-shaped branch boreholes on a single long borehole 30; the method of extending the scope of coverage of the long borehole 30 includes: constructing multiple horizontally arranged parallel boreholes in parallel when constructing the long borehole 30, and at the same time providing a combustion tube 3 in each parallel borehole by increasing the arrangement spacing of the horizontal holes, increasing the speed of dragging the combustion tube 3 and other parameters, thereby reducing the coal consumption per unit length of the coal seam, forming multiple rows of expanded boreholes, and realizing pressure relief and permeability enhancement of the coal seam.

Claims

1. A method for operating a ground long-hole coal body internal combustion fluidized mining device, characterized in that: Surface long-hole coal body internal combustion fluidized mining device, including combustion support system and drainage system; The combustion support system comprises an oxidant tank (21) for filling an oxidant, a reductant tank (23) for filling a reductant and an igniter (19) arranged on the surface, and a combustion pipe (3) and a drainage pipe (2) entering a coal seam borehole through a wellbore (1), wherein a flame head (24) is provided at the end of the combustion pipe (3); the combustion pipe (3) comprises a cable (17) wrapped by a heat-insulating sleeve (26), an oxidant pipe (18), a reductant pipe (20) and a steel wire rope (25), wherein the cable (17) is wrapped by a heat-insulating sleeve (26) The oxidant tank (21) and the reducing agent tank (23) are connected to the flame head (24) through the oxidant tube (18) and the reducing agent tube (20), respectively. The end of the flame head (24) is provided with a nozzle (24-5), and a temperature probe (24-3) and an ignition needle (24-4) are provided inside. The ignition needle (24-4) and the temperature probe (24-3) are connected to the igniter (19) through the ignition wire (24-1) and the temperature sensing wire (24-2). The drainage system includes a heat exchanger (9) and a water-gas separator (12) connected to each other by pipelines, a valve (10) is provided on the pipeline, a refrigerant inlet and a refrigerant outlet (11) are provided on the heat exchanger (9), the heat exchanger (9) is connected to the pumping unit (5) through a mixing pipe (6), the pumping unit (5) is connected to the drainage pipe (2), a screen pipe (4) is provided at the end of the drainage pipe (2), the gas and water extracted by the pumping unit (5) through the drainage pipe (2) enter the heat exchanger (9) through the mixing pipe (6), and then enter the water-gas separator (12) to separate the water and the mixed gas, and the water is discharged from the cold water outlet (14) provided thereon, and the mixed gas is discharged from the mixed gas outlet (13) provided thereon; The working method specifically includes the following steps: a. Install two flame arresters (22) to the ends of the oxidizer tube (18) and the reducing agent tube (20), respectively; install the temperature probe (24-3) to the end of the temperature sensing wire (24-2); install the ignition needle (24-4) to the end of the ignition wire (24-1); align and tighten the flame head sleeve (24-6) and the thermal insulation sleeve (26) and install the nozzle (24-5) to form a flame head (24); and use the combustion tube connected to the flame head (24) as the moving end of the winch (16); b. The oxidant tube (18) and the reducing agent tube (20) separated from the fixed end combustion tube (3) of the winch (16) are respectively connected to the flow meter (7), the valve (10) and the flame arrester (22), and finally connected to the oxidant tank (21) and the reducing agent tank (23); the cable (17) is connected to the igniter (19); c. After the connection is completed, open the valves (10) on the oxidant pipe (18) and the reducing agent pipe (20), and then open the igniter (19) to perform an ignition test to confirm that the ignition is correct; d. Use a drilling rig and a drill rod to construct a long borehole (30) from the ground to the coal seam (28) and lower the wellbore (1), wherein the long borehole (30) includes a vertical section and a coal seam section, wherein the vertical section is a vertical borehole that penetrates the rock layer (27) to reach the coal seam (28), and the coal seam section is a horizontal borehole constructed in the coal seam (28), wherein the angle between the vertical section and the coal seam section is less than 90 degrees, the starting point of the coal seam section is at the lowest point close to the bottom plate, and the end point of the coal seam section is at the highest point close to the top plate of the coal seam (28), so that the coal seam section forms an inclined borehole in the coal seam (28), and the length of the coal seam section is not less than 50 meters; e. Install the screen tube (4) to the end of the drainage pipe (2), and connect the tail end of the drainage pipe (2) to the pumping unit (5), the mixing pipe (6), the flow meter (7), the heat exchanger (9), the valve (10), and the water-gas separator (12) in sequence. Perform an airtightness test to ensure that there is no air leakage. Then, use a drilling rig and a drill pipe to send the combustion tube (3) into the long borehole (30) until the bottom of the hole, and send the drainage pipe (2) into the coal seam section of the long borehole (30); f. Seal the wellbore (1) at the borehole, fix the outer casing (8) of the drainage pipe (2) and the combustion pipe (3), and inject cement mortar into the space inside the wellbore (1) and outside the drainage pipe (2) and the casing (8) to seal; g. Start the pumping unit. If water is pumped out, first use the pumping unit (5) to remove the water. Then, inject a mixed gas in a ratio that allows the oxidant and the reducing agent to burn completely into the borehole. Use the igniter (19) to control the ignition needle (24-4) in the nozzle head (24) to continuously ignite until the temperature transmitted by the temperature probe (24-3) on the igniter (19) is stable at above 500 degrees, indicating that the long borehole (30) is continuously burning. h. Detect the gas composition separated from the mixed gas outlet (13) of the water-gas separator (12) after being extracted by the pumping unit (5). If the concentration of combustible methane, H2 or CO continues to rise, gradually reduce the supply of reducing agent and continue to supply oxidant. Ensure that combustion is maintained inside the borehole by real-time detection through the temperature probe (24-3); i. Calculate the consumption of the coal seam (28) during the combustion process based on the gas flow rate discharged from the mixed gas outlet (13), thereby determining the dragging speed of the combustion tube (3) and the rotation speed of the winch. Then, while maintaining the combustion of the coal seam section of the long borehole (30) by the flame head (24), the winch (16) is generally used to drag the combustion tube (3) toward the vertical section until the coal seam around the coal seam section is completely burned, thereby achieving continuous, stable and controlled combustion of the coal body inside the borehole, and realizing safe and green mining without the gangue leaving the mine and the personnel going down the well. j. When the burner head (24) is dragged to the position of the screen tube (4), the supply of the oxidant and the reducing agent is stopped and extraction is continued; when the temperature displayed on the igniter (19) is below 100°C, it indicates that the flame inside the long borehole (30) has been extinguished; at this time, if the concentration of combustible gas in the extracted mixed gas, including methane, H2, CO, ethane or other alkane gas, is higher than 30%, extraction is continued; if it is lower than 30%, extraction is stopped; K. Continue drilling horizontal branch wells on the basis of the wellbore (1), thereby expanding the coverage of the long borehole (30). After the construction is completed, repeat steps d to j until the designed gasification area of the coal seam is fully covered, completing coal seam combustion gas production; 1. Use the drainage pipe (2) to inject water into the coal seam (28) to ensure that the flames in the goaf after combustion are completely extinguished; remove the combustion pipe (3) and seal the wellbore.

2. The working method of the surface long-hole coal body internal combustion fluidized mining device according to claim 1 is characterized in that: The drainage system also includes a winch (16) arranged on the surface for winding the combustion pipe (3). The winch (16) changes direction through a steering seat (15). The winch (16) is equipped with a steering seat (15) at the wellhead. The rotating shaft on the steering seat (15) converts the drag force of the winch (16) from the tangential direction formed by the winch (16) and the steering seat (15) to the vertical direction.

3. The working method of the surface long-hole coal body internal combustion fluidized mining device according to claim 1 is characterized in that: The flame spray head (24) includes a flame spray head sleeve (24-6), and the ends of the cable (17), the oxidizer tube (18), and the reducing agent tube (20) are all arranged in the flame spray head sleeve (24-6). The end of the flame spray head sleeve (24-6) is a frustum structure, and a plurality of nozzles (24-5) for expanding the flame spray range are provided on the side of the frustum.

4. The operating method of the surface long-hole coal body internal combustion fluidized mining device according to claim 1 is characterized in that: The combustion tube (3) is wrapped by a heat-insulating sleeve (26), and the cross-sections of the oxidant tube (18) and the reducing agent tube (20) are located in the middle of the combustion tube (3) and are symmetrically distributed on the left and right sides. The ignition wire (24-1) and the temperature sensing wire (24-2) are arranged side by side at the upper ends of the oxidant tube (18) and the reducing agent tube (20), and the steel wire rope (25) is located at the lower ends of the oxidant tube (18) and the reducing agent tube (20).

5. The operating method of the surface long-hole coal body internal combustion fluidized mining device according to claim 1, characterized in that: A flow meter (7), a valve (10) and a flame arrester (22) are provided between the oxidant tank (21) and the oxidant pipe (18), and a flow meter (7), a valve (10) and a flame arrester (22) are provided between the reducing agent tank (23) and the reducing agent pipe (20).

6. The operating method of the surface long-hole coal body internal combustion fluidized mining device according to claim 1, characterized in that: The long borehole (30) is mostly vertical in the rock layer (27), then smoothly reaches the bottom plate in the coal layer (28), and further forms a slope of 0.5%-5% in the coal layer.

7. According to the working method of the ground long-hole coal body internal combustion fluidized mining device according to claim 1, the drainage pipe (2) and the combustion pipe (3) located inside the wellbore (1) are sealed for no less than 3 meters at the wellhead.

8. The working method of the ground long-hole coal body internal combustion fluidized mining device according to claim 1, wherein the coverage of the long borehole (30) is expanded through branch wells, including arranging multiple parallel long boreholes (30) in the coal seam (28) through a vertical section; or arranging fishbone-shaped branch boreholes or tree-branch-shaped branch boreholes on a single long borehole (30).

9. The working method according to claim 8, characterized in that: The method of expanding the coverage of the long borehole (30) includes: constructing multiple horizontally arranged parallel boreholes in parallel when constructing the long borehole (30), and at the same time providing a combustion tube (3) in each parallel borehole. By increasing the arrangement spacing of the horizontal holes and increasing the speed parameter of dragging the combustion tube (3), the consumption of coal in the coal seam per unit length is reduced, and multiple rows of expanded boreholes are formed, thereby achieving pressure relief and permeability enhancement of the coal seam.

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