Coal and coal bed gas in-situ co-mining system and method suitable for soft coal bed

Abstract

The invention discloses a coal and coal bed gas in-situ co-mining system and method suitable for a soft coal seam, and relates to the technical field of coal mining. The coal and coal bed gas in-situ co-mining system comprises a shaft, a vertical shaft lifting unit, a mining crushing unit, a secondary crushing unit, a pumping unit, a separating and collecting unit and a top plate stability monitoring unit; the excavating and crushing unit comprises a shell, an excavating mechanism, a water jet mechanism, a conveying mechanism, a crushing mechanism and a moving mechanism; a bottom storage pool is arranged at the bottom of the shaft, the secondary crushing unit is arranged at the bottom of the shaft and located above the bottom storage pool, and the pumping unit is used for pumping a fluidized coal-water mixture subjected to secondary crushing by the secondary crushing unit in the bottom storage pool into the separation and collection unit; and the separating and collecting unit is used for separating and collecting coal, water and coal bed gas. According to the system and the method, the cost is reduced, the mining period is shortened, equipment is prevented from being damaged, normal operation of procedures is prevented from being influenced, and the mining range in the coal seam is widened.

Description

Technical Field

[0001] The present invention relates to the technical field of coal mining, and in particular to an in-situ coal and coalbed methane co-mining system and method suitable for soft coal seams. Background Art

[0002] There are many soft coal seam coal mines and they are widely distributed. These coal seams usually have the characteristics of soft coal structure, high gas content, low permeability, great difficulty in gas extraction and high risk of gas disasters, which are easy to cause gas safety accidents. Therefore, the mining of coal resources and the effective extraction of gas face significant technical challenges. At present, with the introduction of coal and coalbed methane co-mining technology, new solutions are provided to overcome these challenges. In order to improve the utilization efficiency of coal mine resources and the safety of mining, scholars in related fields have developed an integrated mode of protective layer pressure relief coal and gas co-mining and its supporting process technology, and explored new permeability enhancement methods such as sonic shock, ultrasonic, deep hole pre-splitting blasting, and integrated water jet drilling and cutting. However, the existing coal and coalbed methane co-mining technology has problems such as large gas extraction tunnels and drilling projects, high costs, and long cycles, which seriously restricts the implementation of these coal and coalbed methane technologies, especially for soft coal seams. At the same time, since the drilling position and water jet device are in a fixed state, the mining range in the coal seam is limited. At the same time, the coal body flushed by the water jet cannot ensure that the particle size of the coal powder particles is within the range allowed by the pumping device, which can easily cause problems such as pump jamming, damage equipment, and affect the normal progress of the process. Summary of the invention

[0003] To solve the above technical problems, the present invention provides a system and method for in-situ co-mining of coal and coalbed methane suitable for soft coal seams, which reduces costs, shortens the mining cycle, avoids damage to equipment and affects the normal progress of the process, and increases the mining range in the coal seam.

[0004] To achieve the above object, the present invention provides the following solutions:

[0005] The present invention provides a coal and coalbed methane in-situ co-mining system suitable for soft coal seams, comprising a shaft, a shaft lifting unit, a mining and crushing unit, a secondary crushing unit, a pumping unit, a separation and collection unit and a roof stability monitoring unit, wherein the roof stability monitoring unit is used to monitor the strain information of the roof in real time and issue an early warning, the shaft lifting unit includes a device for conveying equipment into the shaft, the mining and crushing unit comprises a shell, a mining mechanism, a water jet mechanism, a transmission mechanism, a crushing mechanism and a moving mechanism, wherein the moving mechanism is arranged at the bottom of the shell, the mining mechanism and the water jet mechanism are arranged at the front end of the shell, the crushing mechanism is arranged at the rear end of the shell, and the transmission mechanism is arranged at the bottom of the shell. The mechanism is arranged in the shell, and is used to transport the coal body cut by the mining mechanism to the crushing mechanism, and the water sprayed by the water jet mechanism is used to convert the coal powder crushed by the crushing mechanism into a fluidized coal-water mixture; a bottom storage tank is arranged at the bottom of the shaft, and the secondary crushing unit is arranged at the bottom of the shaft and located above the bottom storage tank. The secondary crushing unit is used to perform secondary crushing on the fluidized coal-water mixture, and the pumping unit is used to pump the fluidized coal-water mixture in the bottom storage tank that has been secondarily crushed by the secondary crushing unit to the separation and collection unit, and the separation and collection unit is used to separate and collect coal, water and coalbed methane.

[0006] Preferably, the secondary crushing unit includes a bracket, a crushing bin, a feeding bin, a crushing mechanism and a crushing motor, the bracket is arranged above the bottom storage tank, the crushing bin is arranged on the bracket, the feeding bin is arranged on the top of the crushing bin, the crushing mechanism is arranged in the crushing bin, and the crushing motor is used to provide power to the crushing mechanism.

[0007] Preferably, the crushing mechanism comprises an active crushing roller and a driven crushing roller, both ends of the active crushing roller are rotatably installed in the crushing bin, both ends of the driven crushing roller are rotatably installed in the crushing bin, the driven crushing roller is meshed with the active crushing roller, and the crushing motor is used to drive the active crushing roller to rotate.

[0008] Preferably, the feed bin is an inverted cone structure, and the area of ​​the top of the feed bin is larger than the area of ​​the bottom of the shaft.

[0009] Preferably, it also includes a plurality of transfer storage tanks arranged in sequence from bottom to top above the bottom storage tank, and the plurality of transfer storage tanks are all arranged on the same side of the wellbore. The pumping unit includes a bottom pumping mechanism, a top pumping mechanism and an intermediate pumping mechanism. The bottom pumping mechanism is used to pump the fluidized coal-water mixture in the bottom storage tank to the adjacent transfer storage tank, the intermediate pumping mechanism is used to pump the fluidized coal-water mixture in the lower transfer storage tank of two adjacent transfer storage tanks to the upper transfer storage tank, and the top pumping mechanism is used to pump the fluidized coal-water mixture in the uppermost transfer storage tank to the separation and collection unit.

[0010] Preferably, the bottom pumping mechanism includes a bottom pumping pipe and a bottom particle pump arranged on the bottom pumping pipe, and the two ends of the bottom pumping pipe are respectively connected to the bottom storage tank and the adjacent transfer storage tank; the intermediate pumping mechanism includes an intermediate pumping pipe and an intermediate particle pump arranged on the intermediate pumping pipe, and the two ends of the intermediate pumping pipe are respectively connected to the two adjacent transfer storage tanks; the top pumping mechanism includes a top pumping pipe and a top particle pump arranged on the top pumping pipe, and the two ends of the top pumping pipe are respectively connected to the topmost transfer storage tank and the separation and collection unit.

[0011] Preferably, the excavation mechanism comprises a cutter disc housing, a cutting cutter disc, a cutter disc drive assembly and a roller cutter group, the cutter disc housing is arranged at the front end of the shell, the cutting cutter disc is rotatably mounted at the front end of the cutter disc housing, the cutter disc drive assembly is arranged in the cutter disc housing and is used to drive the cutting cutter disc to rotate, the roller cutter group is arranged at the front end of the cutting cutter disc, a plurality of feed holes are arranged on the cutting cutter disc, and a plurality of mounting holes are arranged on the cutting cutter disc; the water jet mechanism comprises a water supply assembly and a plurality of water jet nozzles, each of the mounting holes is provided with a water jet nozzle, the water supply assembly is arranged on the shell and is used to supply water to the water jet nozzles; a transmission chamber and a crushing chamber are arranged in sequence in the shell from front to back, the front end of the transmission chamber is connected to the outlet at the rear end of the cutter disc housing, one end of the transmission mechanism is installed in the cutter disc housing, and the other end is installed in the transmission chamber, the crushing mechanism is arranged in the crushing chamber, and the rear end of the shell is provided with a discharge port corresponding to the position of the crushing chamber.

[0012] The present invention also provides an in-situ coal and coalbed methane co-mining method applicable to soft coal seams, comprising the following steps:

[0013] Step 1: Based on the ground drilling project, a wellbore is excavated, the depth of the wellbore is greater than the depth of the coal seam, a well lifting system is built using the wellbore, and a bottom storage tank with a size greater than the diameter of the wellbore is excavated at the bottom of the wellbore to receive the fluidized coal-water mixture flowing back;

[0014] Step 2: Install a secondary crushing unit above the bottom storage tank, and connect the pumping unit to the bottom storage tank and the separation and collection unit on the ground;

[0015] Step 3: Before coal and coalbed methane mining operations, first deploy the roof stability monitoring unit;

[0016] Step 4: Use the vertical shaft lifting system to transport the mining and crushing unit downward along the shaft to a position close to the top of the coal seam, with the front end of the mining and crushing unit facing the coal seam. After the mining mechanism of the mining and crushing unit contacts the coal seam, it cuts the coal seam along a certain upward coal mining route, and the cut coal body is then transported to the crushing mechanism at the rear end of the mining and crushing unit through the transmission mechanism for crushing. The crushed coal powder falls into the mining tunnel. The water sprayed by the water jet mechanism at the front end of the mining and crushing unit forms a water flow in the mining tunnel, which converts the coal powder into fluidized state. Driven by the water flow and the inclination of the mining tunnel, the fluidized coal-water mixture continuously flows to the rear of the mining until it flows to the shaft and falls.

[0017] Step 5, the fluidized coal-water mixture falls into the secondary crushing unit for further crushing, and then falls into the bottom storage tank;

[0018] Step 6: Use the pumping unit to transport the fluidized coal-water mixture in the bottom storage tank from the bottom of the well to the separation and collection unit on the ground for separation and collection.

[0019] Preferably, in step 4, for the nearly horizontal coal seam, an upward mining method is adopted, and during the mining process, the moving direction of the mining and crushing unit should form a certain angle with the upward inclination of the coal seam;

[0020] For inclined coal seams, during mining, the mining and crushing unit moves in the same direction as the coal seam inclination, and mining is performed along the upward inclination of the coal seam;

[0021] The mining is carried out in a roundabout way. In the same mining plane, the mining and crushing unit takes the boundary between the shaft and the coal seam as the starting point and starts to make an elliptical motion. When the mining and crushing unit returns to the shaft, the mining distance is expanded and the elliptical motion is continued. In this way, the cycle is repeated several times and returns to the starting point.

[0022] For coal seams with a certain thickness, they are mined layer by layer from top to bottom. After a certain range of coal seams near the roof rock layer is mined, when the mining and crushing unit returns to the starting point, the vertical shaft lifting system is used to lower the mining and crushing unit for a distance, and mining is carried out again in the same roundabout mining method until it approaches the bottom rock layer.

[0023] Preferably, in step 4, for the nearly horizontal coal seam, an upward mining method is adopted, and during the mining process, the moving direction of the mining and crushing unit should form a certain angle with the upward inclination of the coal seam;

[0024] For inclined coal seams, during mining, the mining and crushing unit moves in the same direction as the coal seam inclination, and mining is performed along the upward inclination of the coal seam;

[0025] Mining is carried out using a forked mining method. Within the same mining plane, the mining and crushing unit takes the junction of the shaft and the coal seam as the starting point. The mining and crushing unit mines forward for a certain distance to form a main mining tunnel, and then makes a 1 / 4 elliptical motion to the left of the main mining tunnel. When the mining and crushing unit reaches the apex of the ellipse, the mining and crushing unit begins to rotate 90° to the right and mines forward for a certain distance. Then, the mining and crushing unit continues to rotate 90° to the right and makes a 1 / 4 elliptical motion along the previous mining trajectory. When the mining and crushing unit reaches the main mining tunnel, the mining and crushing unit continues to mine forward for a certain distance, and then makes a 1 / 4 elliptical motion to the left of the main mining tunnel. When the mining and crushing unit reaches the apex of the ellipse, the mining and crushing unit begins to rotate 90° to the right and mines forward for a certain distance. Then, the mining and crushing unit continues to rotate 90° to the right and makes a 1 / 4 elliptical motion along the previous mining trajectory. Make a 1 / 4 elliptical motion, and repeat this cycle several times; after mining forward for a distance along the inclination of the coal seam, return to the main mining tunnel, the mining and crushing unit starts to make a 1 / 4 elliptical motion to the right side of the main mining tunnel, when the mining and crushing unit reaches the apex of the ellipse, the mining and crushing unit rotates 90° to the right and mines a certain distance backward, then the mining and crushing unit continues to rotate 90° to the right and makes a 1 / 4 elliptical motion next to the previous mining trajectory, and when reaching the main mining tunnel, move backward for a certain distance along the main mining tunnel, the mining and crushing unit makes a 1 / 4 elliptical motion to the right side of the main mining tunnel, when the mining and crushing unit reaches the apex of the ellipse, the mining and crushing unit rotates 90° to the right and mines a certain distance backward, then the mining and crushing unit continues to rotate 90° to the right and makes a 1 / 4 elliptical motion next to the previous mining trajectory, and repeats this cycle several times until it reaches the starting position;

[0026] For coal seams with a certain thickness, they are mined layer by layer from top to bottom. After a certain range of coal seams near the roof rock layer has been mined, when the mining and crushing unit returns to the starting point, the vertical shaft lifting system is used to lower the mining and crushing unit for a distance, and mining is carried out again using the same forked mining method until it approaches the bottom rock layer.

[0027] Compared with the prior art, the present invention has achieved the following technical effects:

[0028] The in-situ co-mining system of coal and coalbed methane suitable for soft coal seams of the present invention utilizes a mining and crushing unit to mine and crush the coal body along the upward coal mining route. The coal body is transformed into a fluidized resource under the impact of a water jet. Under the action of hydraulic scouring and its own gravity, it flows to the shaft through the mined mining tunnel, flows downward along the shaft wall, and reaches the secondary crushing unit at the bottom of the shaft. The unit further reduces the particle size of the coal powder particles through extrusion and crushing, so that it reaches a size suitable for pumping and falls into the bottom storage tank. Subsequently, the fluidized coal-water mixture is transported to the ground through a pumping unit. On the ground, the separation and collection unit is used to separate and collect coal, water and coalbed methane, thereby completing the entire process of in-situ co-mining of coal and coalbed methane in soft coal seams. After the mined coal body is crushed multiple times, the particle size of the overall particles in the fluidized coal-water mixture is reduced to the maximum particle size requirement allowed by the pumping unit, avoiding damage to the equipment and affecting the normal progress of the process. The mining and crushing unit can move flexibly, which increases the scope of mining in the coal seam. The system and method of the present invention save manpower and material resources, as well as preparation time for mining to a great extent, and there is no need to open up tunnels and chambers in advance, and no ventilation is required, which reduces the cost of tunnel construction, maintenance and coal transportation, increases the recovery rate of coal resources, greatly improves the intelligence level of coal mining, and shortens the mining cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0030] Figure 1 A schematic diagram of the structure of the in-situ coal and coalbed methane co-mining system applicable to soft coal seams provided by the present invention;

[0031] Figure 2 A schematic diagram of mining an inclined coal seam by the coal and coalbed methane in-situ mining system applicable to soft coal seams provided by the present invention;

[0032] Figure 3A schematic diagram of the structure of a secondary crushing unit in an in-situ coal and coalbed methane co-mining system applicable to soft coal seams provided by the present invention;

[0033] Figure 4 A three-dimensional structural diagram of a mining and crushing unit in an in-situ coal and coalbed methane co-mining system applicable to soft coal seams provided by the present invention;

[0034] Figure 5 The internal structure diagram of the mining and crushing unit in the in-situ mining system of coal and coalbed methane applicable to soft coal seams provided by the present invention;

[0035] Figure 6 A front view of a mining and crushing unit in an in-situ coal and coalbed methane co-mining system applicable to soft coal seams provided by the present invention;

[0036] Figure 7 A top view of the in-situ coal and coalbed methane co-mining method applicable to soft coal seams provided by the present invention, which adopts a circuitous mining method;

[0037] Figure 8 A three-dimensional structural diagram of the in-situ coal and coalbed methane co-mining method applicable to soft coal seams provided by the present invention, which adopts a circuitous mining method;

[0038] Fig. 9 A front view of the in-situ coal and coalbed methane co-mining method applicable to soft coal seams provided by the present invention using a circuitous mining method;

[0039] Fig.10 A three-dimensional structural diagram of the in-situ coal and coalbed methane co-mining method applicable to soft coal seams provided by the present invention, in which a circuitous mining method is adopted in multiple shafts;

[0040] Fig.11 A top view of the decomposed steps of the in-situ coal and coalbed methane mining method applicable to soft coal seams provided by the present invention using a circuitous mining method;

[0041] Fig.12 A top view of the in-situ coal and coalbed methane co-mining method applicable to soft coal seams provided by the present invention using a bifurcated mining method;

[0042] Fig.13 A three-dimensional structural diagram of the in-situ coal and coalbed methane co-mining method applicable to soft coal seams provided by the present invention, which adopts a bifurcated mining method;

[0043] Fig.14 A front view of the in-situ coal and coalbed methane mining method applicable to soft coal seams provided by the present invention using a bifurcated mining method;

[0044] Fig.15A three-dimensional structural diagram of the in-situ coal and coalbed methane co-mining method applicable to soft coal seams provided by the present invention, in which a bifurcated mining method is adopted in multiple shafts;

[0045] Fig.16 A top view of the decomposed steps of the in-situ coal and coalbed methane co-mining method suitable for soft coal seams provided by the present invention using a bifurcated mining method.

[0046] Explanation of the reference numerals: 1. coal seam; 2. roof rock layer; 3. floor rock layer; 4. bottom storage tank; 5. transfer storage tank; 6. secondary crushing unit; 61. bracket; 62. feed bin; 63. crushing bin; 64. active crushing roller; 65. driven crushing roller; 7. mining and crushing unit; 71. shell; 72. mobile crawler; 73. water pump; 74. water pump motor; 75. cutter head shell; 76. cutting cutter head; 77. single-edged hob; 78. double-edged hob; 79. feed hole; 710. water jet nozzle; 711. cylindrical cavity; 712. conical cavity; 713. crushing cavity; 714. screw; 715. transmission motor; 716. crushing blade; 8. fluidized coal-water mixture; 9. roof stability monitoring unit; 10. shaft; 11. vertical shaft lifting Downstream unit; 12. Separation and collection unit; 13. Water reservoir; 14. Bottom particle pump; 15. Middle particle pump; 16. Top particle pump; 17. First mining tunnel; 171. First circle mining route; 172. Second circle mining route; 173. Third circle mining route; 174. Fourth circle mining route; 175. Nth circle mining route; 18. First legacy coal pillar; 19. Second mining tunnel; 191. First fork mining tunnel; 192. Second fork mining tunnel; 193. Third fork mining tunnel; 194. Fourth fork mining tunnel; 195. Fifth fork mining tunnel; 196. Sixth fork mining tunnel; 197. Seventh fork mining tunnel; 198. Eighth fork mining tunnel; 20. Second legacy coal pillar; 21. Mining main tunnel. DETAILED DESCRIPTION

[0047] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0048] The purpose of the present invention is to provide a system and method for in-situ co-mining of coal and coalbed methane suitable for soft coal seams, which reduces costs, shortens the mining cycle, avoids damage to equipment and affects the normal progress of the process, and increases the mining range in the coal seam.

[0049] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0050] like Figure 1-Figure 16 As shown, this embodiment provides a coal and coalbed methane in-situ co-mining system suitable for soft coal seams, including a shaft 10, a shaft lifting unit 11, a mining and crushing unit 7, a secondary crushing unit 6, a pumping unit, a separation and collection unit 12 and a roof stability monitoring unit 9. The roof stability monitoring unit 9 is used to monitor the strain information of the roof in real time and issue an early warning. The shaft lifting unit 11 includes a device for conveying equipment into the shaft 10. The mining and crushing unit 7 includes a shell 71, a mining mechanism, a water jet mechanism, a transmission mechanism, a crushing mechanism and a moving mechanism. The moving mechanism is arranged at the bottom of the shell 71. The moving mechanism is used to drive the entire device to move. The mining mechanism and the water jet mechanism are arranged at the front end of the shell 71, the crushing mechanism is arranged at the rear end of the shell 71, and the transmission mechanism is arranged at the bottom of the shell 71. It is placed in the shell 71 and is used to transport the coal body cut by the mining mechanism to the crushing mechanism. The water sprayed by the water jet mechanism is used to convert the coal powder crushed by the crushing mechanism into a fluidized coal-water mixture 8; a bottom storage tank 4 is provided at the bottom of the shaft 10, and a secondary crushing unit 6 is provided at the bottom of the shaft 10 and located above the bottom storage tank 4. The secondary crushing unit 6 is used to perform secondary crushing on the fluidized coal-water mixture 8 to prevent the fluidized coal-water mixture 8 from entraining large-particle coal powder during the flow process, thereby affecting the subsequent pumping process; the pumping unit is used to pump the fluidized coal-water mixture 8 that has been secondarily crushed by the secondary crushing unit 6 in the bottom storage tank 4 to the separation and collection unit 12, and the separation and collection unit 12 is used to separate and collect coal, water and coalbed methane.

[0051] In this embodiment, the mining and crushing unit 7 is used to mine and crush the coal body along the upward coal mining route. The coal body is transformed into a fluidized resource under the impact of a water jet. Under the action of hydraulic scouring and its own gravity, it flows through the mined mining tunnel to the shaft 10, flows downward along the shaft 10 wall, and reaches the secondary crushing unit 6 at the bottom of the shaft. The unit further reduces the particle size of the coal powder particles through extrusion and crushing, so that it reaches a size suitable for pumping and falls into the bottom storage tank 4. Subsequently, the fluidized coal-water mixture is transported to the ground through the pumping unit, and on the ground, the separation and collection unit 12 is used to separate and collect coal, water and coalbed methane, thereby completing the entire process of in-situ co-mining of soft coal and coalbed methane. After the mined coal body is crushed multiple times, the particle size of the overall particles in the fluidized coal-water mixture is reduced to the maximum particle size requirement allowed by the pumping unit, avoiding damage to the equipment and affecting the normal progress of the process. The mining and crushing unit 7 can move flexibly, which increases the mining range in the coal seam 1. The system and method of the present invention greatly saves manpower and material resources, as well as the preparation time for mining, and there is no need to open up tunnels and chambers in advance, and there is no need for ventilation, which reduces the cost of tunnel construction, maintenance and coal transportation, improves the recovery rate of coal resources, greatly improves the intelligence level of coal mining, and shortens the mining cycle. Through the unmanned operation mode underground, casualties are avoided, which not only realizes the optimal utilization of resources, but also protects the ecological environment of the mining area, and effectively promotes the process of coal resource mining to intelligent unmanned mining mode.

[0052] Specifically, the vertical shaft lifting unit 11 includes a derrick, a steel wire rope, a shaft 10, an elevator and a control system. The vertical shaft lifting unit 11 in this embodiment is a structure in the prior art.

[0053] Specifically, multiple shafts 10 are arranged within the mining area, and the mining areas do not affect each other.

[0054] like Figure 3 As shown, the secondary crushing unit 6 includes a bracket 61, a crushing bin 63, a feed bin 62, a crushing mechanism and a crushing motor. The bracket 61 is arranged above the bottom storage tank 4, the crushing bin 63 is arranged on the bracket 61, the feed bin 62 is arranged on the top of the crushing bin 63, the crushing mechanism is arranged in the crushing bin 63, and the crushing motor is used to provide power to the crushing mechanism.

[0055] The crushing mechanism includes an active crushing roller 64 and a driven crushing roller 65. Both ends of the active crushing roller 64 are rotatably installed in the crushing bin 63. Both ends of the driven crushing roller 65 are rotatably installed in the crushing bin 63. The driven crushing roller 65 and the active crushing roller 64 are meshed with each other. The crushing motor is used to drive the active crushing roller 64 to rotate.

[0056] In this embodiment, the gap between the active crushing roller 64 and the driven crushing roller 65 is relatively small, so as to avoid the occurrence of large discharge particle size at the discharge port.

[0057] In order to conveniently receive the fluidized coal-water mixture 8 flowing down from the mining tunnel, the feed bin 62 is an inverted cone structure, and the area of ​​the top of the feed bin 62 is larger than the area of ​​the bottom of the shaft 10 .

[0058] The present embodiment also includes a plurality of transfer storage tanks 5 arranged sequentially from bottom to top above the bottom storage tank 4, and the plurality of transfer storage tanks 5 are all located on the same side of the wellbore 10. The pumping unit includes a bottom pumping mechanism, a top pumping mechanism and an intermediate pumping mechanism, the bottom pumping mechanism is used to pump the fluidized coal-water mixture 8 in the bottom storage tank 4 to the adjacent transfer storage tank 5, the intermediate pumping mechanism is used to pump the fluidized coal-water mixture 8 in the lower transfer storage tank 5 of the two adjacent transfer storage tanks 5 to the upper transfer storage tank 5, and the top pumping mechanism is used to pump the fluidized coal-water mixture 8 in the uppermost transfer storage tank 5 to the separation and collection unit 12. The transfer storage tank 5 serves as a transfer station in the pumping process of the fluidized coal-water mixture 8 until the fluidized coal-water mixture 8 is transported to the ground.

[0059] The bottom pumping mechanism includes a bottom pumping pipe and a bottom particle pump 14 arranged on the bottom pumping pipe, and the two ends of the bottom pumping pipe are respectively connected to the bottom storage tank 4 and the adjacent transfer storage tank 5; the intermediate pumping mechanism includes an intermediate pumping pipe and an intermediate particle pump 15 arranged on the intermediate pumping pipe, and the two ends of the intermediate pumping pipe are respectively connected to the two adjacent transfer storage tanks 5; the top pumping mechanism includes a top pumping pipe and a top particle pump 16 arranged on the top pumping pipe, and the two ends of the top pumping pipe are respectively connected to the top transfer storage tank 5 and the separation and collection unit 12.

[0060] The maximum particle size of the conveying fluid of the bottom particle pump 14 and the intermediate particle pump 15 in this embodiment does not exceed 10 mm, and the maximum conveying head is 120 m. When conveying materials to a relatively high position, it is necessary to set up several intermediate particle pumps 15 in the longitudinal direction to convey the materials from the bottom of the wellbore 10 to the ground.

[0061] The roof stability monitoring unit 9 in this embodiment is a distributed optical fiber monitoring system for the roof rock layer 2, which monitors the strain information of the roof in real time and issues an early warning by analyzing the changes in the optical signal transmitted in the optical fiber. The optical cable used in the distributed optical fiber monitoring system for the roof rock layer 2 is selected to have a high tensile strength and shear strength to avoid being crushed and damaged by the broken rock blocks of the roof.

[0062] The separation and collection unit 12 in this embodiment is a coal-water-gas three-phase separation device.

[0063] like Figure 4-Figure 6As shown, the mining mechanism includes a cutterhead housing 75, a cutting disc 76, a cutterhead drive assembly and a roller cutter group. The cutterhead housing 75 is arranged at the front end of the shell 71, and the cutting disc 76 is rotatably installed at the front end of the cutterhead housing 75. The cutterhead drive assembly is arranged in the cutterhead housing 75 and is used to drive the cutting disc 76 to rotate. A roller cutter group is arranged at the front end of the cutting disc 76. The cutting disc 76 is provided with a plurality of feed holes 79. The cut and crushed coal body can enter the cutterhead housing 75 through the feed holes 79. The cutting disc 76 is provided with a plurality of mounting holes.

[0064] The water jet mechanism includes a water supply component and a plurality of water jet nozzles 710, each mounting hole is provided with a water jet nozzle 710, the water supply component is arranged on the shell 71, and is used to supply water to the water jet nozzle 710; a transmission chamber and a crushing chamber 713 are arranged in sequence from front to back in the shell 71, the front end of the transmission chamber is connected to the outlet at the rear end of the cutter disc housing 75, one end of the transmission mechanism is installed in the cutter disc housing 75, and the other end is installed in the transmission chamber, the transmission mechanism is used to transport the coal body in the cutter disc housing 75 backward to the crushing chamber 713, the crushing mechanism is arranged in the crushing chamber 713, and the rear end of the shell 71 is provided with a discharge port corresponding to the position of the crushing chamber 713, the crushing mechanism is used to further crush the coal body transported to the crushing chamber 713 to avoid the generation of large-size coal blocks, and then discharge it to the rear of the mining and crushing unit 7 through the discharge port.

[0065] In this embodiment, the technology of combining the cutting disc 76 with the high-pressure water jet is adopted to realize the efficient cutting and crushing of the coal body, significantly improving the efficiency of coal mining. The mined coal body is transported to the crushing chamber 713 through the transmission mechanism and crushed by the crushing mechanism, further reducing the particle size of the cut coal body, realizing the continuity of mining and transportation, reducing the intermediate links, and improving the operation efficiency. The flushing effect of the high-pressure water jet promotes the fluidization of the coal body, provides conditions for the self-flowing transportation of the coal body in the roadway, thereby reducing the dependence on traditional transportation equipment. The crushed coal body flows into the shaft 10 along the roadway under the dual effects of high-pressure water flow and gravity, realizing the continuous transportation of the coal body and reducing the energy consumption and equipment requirements of the transportation link.

[0066] A support frame is provided in the blade housing 75, and the central axis at the rear end of the cutting blade 76 is rotatably mounted on the support frame through a bearing, and the cutting blade 76 fits with the front end of the blade housing 75, and the blade drive assembly is used to drive the central axis to rotate.

[0067] The cutter head drive assembly includes a cutter head motor and a transmission gear box, both of which are arranged at the upper part of the cutter head housing 75, the cutter head motor is connected to the power input end of the transmission gear box, and the power output end of the transmission gear box is connected to the central shaft. The transmission gear box and the cutter head motor in this embodiment are arranged in sequence from front to back.

[0068] The plurality of roller cutters include a plurality of single-edged roller cutters 77 and a plurality of double-edged roller cutters 78. The surface shape of the cutting blade disc 76 adopts a spoke plate type, and a feed hole 79 is provided between any two adjacent spoke plates. The plurality of double-edged roller cutters 78 are concentrated in the middle of the spoke plate, and the plurality of single-edged roller cutters 77 are arranged on the surface of the spoke plate in a concentric circle to improve cutting efficiency and uniformity.

[0069] In this specific embodiment, the blade housing 75 and the cutting blade 76 are both welded by steel structures, and the diameter of the cutting blade 76 is 0.3m to 0.5m.

[0070] In this specific embodiment, the shell 71 is a cylindrical flexible shell. The cylindrical flexible shell has a certain tolerance to the collision and friction generated when the mining and excavation integrated equipment moves in the coal seam 1, and is not prone to wear.

[0071] Specifically, the specific material of the cylindrical flexible shell is thermoplastic polyurethane or carbon fiber composite material, which has wear resistance, flexibility and tear resistance, can withstand greater collisions and frictions, and has good processing performance and plasticity.

[0072] The water supply assembly includes a water pump 73, a water pump motor 74, a rotary joint, a main hose and a plurality of branch hoses. The water pump 73 and the water pump motor 74 are both arranged at the upper part of the housing 71. The water pump motor 74 is used to drive the water pump 73. One end of the main hose is connected to the outlet of the water pump 73 through a rotary joint. The other end of the main hose is connected to a plurality of branch hoses. The end of each branch hose away from the main hose is connected to a water jet nozzle 710. The water jet nozzle 710 is arranged on the cutting disc 76 and rotates with the cutting disc 76. The rotary joint is arranged so that the plurality of branch hoses and the main hose can rotate with the water jet nozzle 710.

[0073] In order to realize the continuous supply of water resources, the inlet of the water pump 73 is connected to one end of the connecting hose, and the other end of the connecting hose is connected to the water source on the ground.

[0074] During operation, the water in the water pump 73 is converted into high-pressure water flow through the main hose and the branch hose, and is sprayed out by the water jet nozzle 710 to flush the coal body cut in front and soften the coal body in front of the equipment to reduce the strength of the coal body, promote the crushing process of the coal body and convert it into a form of resource that is easy to transport. At the same time, it promotes the conversion of coal powder that falls into the tunnel into a fluidized state that is easy to transport.

[0075] In this specific embodiment, the jet direction of the water jet nozzle 710 is perpendicular to the cutting blade disc 76. There are four water jet nozzles 710, which are distributed in the middle of the cutting blade disc 76 and are evenly distributed along the circumference of the cutting blade disc 76.

[0076] In this specific embodiment, both the main hose and the branch hose are high-pressure hoses.

[0077] The transmission mechanism includes a first support, a second support, a screw 714 and a transmission motor 715. The first support is arranged at the lower part of the cutter head housing 75, the second support is arranged at one end of the transmission chamber close to the crushing chamber 713, the two ends of the screw 714 are rotatably mounted in the first support and the second support respectively, and the transmission motor 715 is arranged on the second support and is used to drive the screw 714 to rotate. When working, the transmission motor 715 drives the screw 714 to rotate, and transports the coal in the cutter head housing 75 to the crushing chamber 713.

[0078] Specifically, one end of the screw rod 714 is rotatably mounted in the first support via a bearing, and the other end of the screw rod 714 is rotatably mounted in the second support via a bearing.

[0079] The crushing mechanism includes two crushing components, which are arranged in the crushing chamber 713 from left to right. The crushing components include a crushing motor, a rotating shaft and a plurality of crushing blades 716. The rotating shaft is vertically arranged in the crushing chamber 713, and the two ends of the rotating shaft are rotatably installed on the shell 71 respectively. A plurality of crushing blades 716 are arranged in sequence on the rotating shaft along the axial direction. The crushing motor is arranged on the shell 71 and connected to the upper end of the rotating shaft. The plurality of crushing blades 716 on the two rotating shafts are staggered.

[0080] When working, the crushing motor is started, and when it contacts the coal body, the crushing blades 716 squeeze each other to discharge small-size coal powder. The two crushing motors control the two rotating shafts respectively, and then the rotation speed and direction of the crushing blades 716 on the two rotating shafts respectively, so as to optimize the crushing effect.

[0081] In this specific embodiment, the crushing blade 716 is made of special alloy steel.

[0082] The transmission chamber includes a cylindrical chamber 711 and a conical chamber 712 which are arranged in sequence from front to back. The front end of the cylindrical chamber 711 is connected to the outlet at the rear end of the cutter housing 75, and the rear end of the conical chamber 712 is connected to the crushing chamber 713. The cross-sectional area of ​​the conical chamber 712 gradually increases from front to back, and the cross-sectional area of ​​the front end of the conical chamber 712 is the same as the cross-sectional area of ​​the cylindrical chamber 711. In this embodiment, the cylindrical chamber 711 is a cylindrical chamber.

[0083] The second support is arranged at the connection of the columnar cavity 711 and the conical cavity 712, and the transmission motor 715 is arranged in the conical cavity 712. The conical cavity 712 is arranged to connect the columnar cavity 711 provided with the screw 714 and the crushing cavity 713, so that the cut coal body can be smoothly transitioned and continuously crushed.

[0084] The moving mechanism includes a moving track 72 and a track motor. The moving track 72 is arranged at the bottom of the shell 71. The track motor is used to drive the moving track 72 to move. The moving track 72 is controlled by the track motor to realize the movement and steering of the entire equipment, so that it can move and turn freely, and has strong flexibility.

[0085] The mining and crushing unit 7 in this embodiment is equipped with a mobile crawler 72, which can move and turn autonomously in the tunnel, thereby improving the maneuverability and flexibility of the equipment, realizing intelligent unmanned mining of coal mines, and improving the safety of coal mining.

[0086] The cutter head motor, water pump motor 74, transmission motor 715, crushing motor and crawler motor in this embodiment are all high-power motors to ensure the continuity and efficiency of the equipment during the tunnel excavation process.

[0087] The mining and crushing unit 7 in this embodiment integrates mining, transmission, crushing, movement and fluidization processing, has a compact structure, a small overall size, and occupies a small space. The disturbance to the coal seam 1 during the mining process is minimized, thereby effectively protecting the integrity of the structure of the coal seam 1, reducing the impact on the surrounding environment, improving mining efficiency, and reducing mining costs. It is a miniaturized, integrated, and highly efficient mining integrated equipment. The mining and crushing unit 7 in this embodiment realizes the mining and crushing of the coal body, and at the same time converts the crushed coal body into a fluidized resource that can be transmitted, which not only avoids dust pollution in the tunnel, but also can adapt to narrow mining space, improves the operating efficiency under complex geological conditions, and achieves the purpose of safe and efficient in-situ mining of coal reservoirs.

[0088] This embodiment also provides a method for in-situ co-mining of coal and coalbed methane applicable to soft coal seams, comprising the following steps:

[0089] Step 1: Based on the ground drilling project, a large-diameter wellbore 10 is excavated. The depth of the wellbore 10 must be greater than the depth of the coal seam 1. The wellbore 10 is used to build a well lifting system, and a bottom storage tank 4 with a size larger than the diameter of the wellbore 10 is excavated at the bottom of the wellbore 10 to receive the fluidized coal-water mixture 8 that flows back.

[0090] Step 2: Install the secondary crushing unit 6 above the bottom storage tank 4, and connect the pumping unit to the bottom storage tank 4 and the separation and collection unit 12 on the ground. According to the specific depth of the coal seam 1 and the lift of the particle pump, multiple transfer storage tanks 5 are installed at intervals in the longitudinal direction on one side of the wellbore 10 as transfer stations in the pumping process of the fluidized coal-water mixture 8 until the fluidized coal-water mixture 8 is transported to the ground.

[0091] Step 3: Before coal and coalbed methane mining operations, the roof stability monitoring unit 9 is deployed. The distributed optical fiber monitoring system for the roof rock layer 2 in this embodiment can determine the maximum mining range of the mining and crushing unit 7 during coal tunneling by monitoring the roof stability.

[0092] Step 4: Use the vertical shaft lifting system to transport the mining and crushing unit 7 downward along the shaft 10 to a position close to the top of the coal seam 1. The front end of the mining and crushing unit 7 faces the coal seam 1. After the mining mechanism of the mining and crushing unit 7 contacts the coal seam 1, it cuts the coal seam 1 along a certain upward coal mining route. The cut coal body is then transported to the crushing mechanism at the rear end of the mining and crushing unit 7 through the transmission mechanism for crushing. The crushed coal powder falls into the mining tunnel. The water sprayed by the water jet mechanism at the front end of the mining and crushing unit 7 forms a water flow in the mining tunnel, which converts the coal powder into fluidized state. Driven by the water flow and the inclination of the mining tunnel, the fluidized coal-water mixture 8 continuously flows toward the rear of the mining until it flows to the shaft 10 and falls down.

[0093] Step 5. The fluidized coal-water mixture 8 falls into the secondary crushing unit 6 for crushing again, and then falls into the bottom storage tank 4. Through the extrusion between the crushing rollers in the crushing bin, the fluidized coal-water mixture 8 falling into the bottom storage tank 4 does not contain large particles of coal powder, thereby ensuring that the particle size of the fluidized coal-water mixture 8 meets the maximum particle size for pumping, avoiding large-size coal powder being entrained in the fluidized coal powder mixture, which affects the subsequent pumping process.

[0094] Step 6: Use a pumping unit to transport the fluidized coal-water mixture 8 in the bottom storage tank 4 from the bottom of the well to the separation and collection unit 12 on the ground for separation and collection. The separation and collection unit 12 separates and collects the three phases of coal, water and coalbed methane, and stores the separated water resources in the water storage tank 13 for recycling.

[0095] like Figure 7-Figure 11 As shown, in this specific embodiment, in step four, for the nearly horizontal coal seam (<5°), an upward mining method is adopted. During the mining process, the moving direction of the mining and crushing unit 7 must form a certain angle with the upward inclination of the coal seam 1, and the angle should not be too large.

[0096] For inclined coal seams, gently inclined coal seams (5°~10°), inclined coal seams (10°~45°) and steeply inclined coal seams, during the mining process, the moving direction of the mining and crushing unit 7 is consistent with the inclination of the coal seam 1, and mining is carried out along the upward inclination of the coal seam 1.

[0097] In order to ensure the stability of the coal seam 1 and the mining tunnel as much as possible, a first residual coal pillar 18 is left in the coal seam 1 for support, and a roundabout mining method is adopted. In the same mining plane, the mining and crushing unit 7 starts to make elliptical motion with the junction of the shaft 10 and the coal seam 1 as the starting point. When the mining and crushing unit 7 returns to the shaft 10, the mining distance is expanded and the elliptical motion is continued. In this way, the cycle is repeated several times and returns to the starting point.

[0098] For a coal seam 1 with a certain thickness, it is mined layer by layer from top to bottom. After a certain range of the coal seam 1 near the roof rock layer 2 is mined, when the mining and crushing unit 7 returns to the starting point, the vertical shaft lifting system is used to lower the mining and crushing unit 7 for a distance, and mining is carried out again in the same roundabout mining method until it approaches the bottom rock layer 3.

[0099] Specifically, the mining and crushing unit 7 mines the coal seam 1 along the elliptical first mining route 171. When the mining returns to the starting point after one round, the mining angle and the mining range are increased, and mining is carried out along the second mining route 172. When the mining returns to the starting point after one round, the mining angle and the mining range are continued to be increased, and mining is carried out along the third mining route 173. Subsequently, when the mining returns to the starting point after one round, the mining angle and the mining range are continued to be increased, and mining is carried out along the fourth mining route 174. This cycle is repeated until mining is carried out along the nth mining route 175, and when the upper plane is mined to a certain range, the middle part of the coal seam 1 and the bottom of the coal seam 1 are mined downward in the vertical direction. The first mining route 171, the second mining route 172, the third mining route 173, the fourth mining route 174 and the nth mining route 175 are collectively referred to as the first mining roadway 17.

[0100] like Figure 12-16 As shown, in another specific embodiment, in step four, for the nearly horizontal coal seam (<5°), an upward mining method is adopted. During the mining process, the moving direction of the mining and crushing unit 7 should form a certain angle with the upward inclination of the coal seam 1, and the angle should not be too large.

[0101] For inclined coal seams, gently inclined coal seams (5°~10°), inclined coal seams (10°~45°) and steeply inclined coal seams, during the mining process, the moving direction of the mining and crushing unit 7 is consistent with the inclination of the coal seam 1, and mining is carried out along the upward inclination of the coal seam 1.

[0102] In order to ensure the stability of the coal seam 1 and the mining tunnel as much as possible, a second residual coal pillar 20 is left in the coal seam 1 for support, and a forked mining method is adopted for mining. In the same mining plane, the mining and crushing unit 7 takes the junction of the shaft 10 and the coal seam 1 as the starting point, and the mining and crushing unit 7 mines forward for a certain distance to form the main mining tunnel 21, and then makes a 1 / 4 elliptical motion to the left of the main mining tunnel 21. When the mining and crushing unit 7 reaches the apex of the ellipse, the mining and crushing unit 7 begins to rotate 90° to the right and mines forward for a certain distance, and then the mining and crushing unit 7 continues to rotate 90° to the right and makes a 1 / 4 elliptical motion along the previous mining trajectory; when the mining and crushing unit 7 reaches the main mining tunnel 21, the mining and crushing unit 7 continues to mine forward for a certain distance, and then makes a 1 / 4 elliptical motion to the left of the main mining tunnel 21. When the mining and crushing unit 7 reaches the apex of the ellipse, the mining and crushing unit 7 begins to rotate 90° to the right and mines forward for a certain distance, and then the mining and crushing unit 7 Continue to rotate 90° to the right, and make a 1 / 4 elliptical motion along the previous mining trajectory, and repeat this cycle several times; after mining forward for a distance along the inclination of the coal seam 1, return to the main mining tunnel 21, and the mining and crushing unit 7 begins to make a 1 / 4 elliptical motion to the right side of the main mining tunnel 21. When the mining and crushing unit 7 reaches the apex of the ellipse, the mining and crushing unit 7 rotates 90° to the right and mines a certain distance backward. Then the mining and crushing unit 7 continues to rotate 90° to the right, and makes a 1 / 4 elliptical motion along the previous mining trajectory. When reaching the main mining tunnel 21, move backward along the main mining tunnel 21 for a certain distance. The mining and crushing unit 7 makes a 1 / 4 elliptical motion to the right side of the main mining tunnel 21. When the mining and crushing unit 7 reaches the apex of the ellipse, the mining and crushing unit 7 rotates 90° to the right and mines a certain distance backward. Then the mining and crushing unit 7 continues to rotate 90° to the right, and makes a 1 / 4 elliptical motion along the previous mining trajectory. Repeat this cycle several times until it reaches the starting position.

[0103] For a coal seam 1 with a certain thickness, it is mined layer by layer from top to bottom. After a certain range of the coal seam 1 near the roof rock layer 2 is mined, when the mining and crushing unit 7 returns to the starting point, the vertical shaft lifting system is used to lower the mining and crushing unit 7 for a distance, and mining is carried out again with the same forked mining method until it approaches the bottom rock layer 3.

[0104] Specifically, the mining and crushing unit 7 first moves to the left at a certain angle along the first forked mining tunnel 191 to make a quarter elliptical motion. When it reaches the apex of the quarter ellipse, the mining and crushing unit 7 rotates 90° to the right, turns the body, and mines forward for a certain distance. Then, the mining and crushing unit 7 continues to rotate 90° to the right, and returns to the mining main tunnel 21 along the second forked mining tunnel 192 next to the first forked mining tunnel 191. Then, the mining and crushing unit 7 rotates to the left, turns the body to be parallel to the mining main tunnel 21, and moves to the left at a certain angle along the third forked mining tunnel 193 to make a quarter elliptical motion. When it reaches the apex of the quarter ellipse, the mining and crushing unit 7 rotates 90° to the right, turns the body, and mines forward for a certain distance. Then, the mining and crushing unit 7 continues to rotate 90° to the right, and returns to the mining main tunnel 21 along the fourth forked mining tunnel 194 next to the third forked mining tunnel 193.

[0105] When the mining and crushing unit 7 returns to the main mining tunnel 21, the machine body is adjusted to mine the other side of the coal seam 1, and a quarter ellipse is made at a certain angle along the fifth bifurcated mining tunnel 195. When reaching the vertex of the quarter ellipse, the mining and crushing unit 7 rotates 90° to the right, turns the machine body around, and mines a certain distance backwards, and then the mining and crushing unit 7 continues to rotate 90° to the right, and returns to the main mining tunnel 21 along the sixth bifurcated mining tunnel 196 next to the fifth bifurcated mining tunnel 195. Then the mining and crushing unit 7 rotates to the left, turns the machine body to be parallel to the main mining tunnel 21, and moves to the right at a certain angle along the seventh bifurcated mining tunnel 197 to make a 1 / 4 ellipse. When it reaches the vertex of the 1 / 4 ellipse, the mining and crushing unit 7 rotates 90° to the right, turns the machine body and mines a certain distance backward. Then the mining and crushing unit 7 continues to rotate 90° to the right, and mines back to the main mining tunnel 21 along the eighth bifurcated mining tunnel 198 next to the seventh bifurcated mining tunnel 197. After returning to the starting point, the middle of the coal seam 1 and the bottom of the coal seam 1 are mined downward in sequence in the vertical direction.

[0106] Specifically, the mining and crushing unit 7 is rotating, and the equipment still performs coal mining. The first forked mining tunnel 191, the second forked mining tunnel 192, the third forked mining tunnel 193, the fourth forked mining tunnel 194, the fifth forked mining tunnel 195, the sixth forked mining tunnel 196, the seventh forked mining tunnel 197 and the eighth forked mining tunnel 198 are collectively referred to as the second mining tunnel 19, and are not limited to the number shown in the figure, and there are several.

[0107] The present specification uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. An in-situ coal and coalbed methane co-mining system suitable for soft coal seams, characterized in that: It includes a shaft, a shaft lifting unit, an excavation and crushing unit, a secondary crushing unit, a pumping unit, a separation and collection unit and a roof stability monitoring unit. The roof stability monitoring unit is used to monitor the strain information of the roof in real time and issue an early warning. The shaft lifting unit includes a device for conveying equipment into the shaft. The excavation and crushing unit includes a shell, an excavation mechanism, a water jet mechanism, a transmission mechanism, a crushing mechanism and a moving mechanism. The moving mechanism is arranged at the bottom of the shell, the excavation mechanism and the water jet mechanism are arranged at the front end of the shell, the crushing mechanism is arranged at the rear end of the shell, the transmission mechanism is arranged in the shell, and is used to The coal body cut by the mining mechanism is transported to the crushing mechanism, and the water sprayed by the water jet mechanism is used to convert the coal powder crushed by the crushing mechanism into a fluidized coal-water mixture; a bottom storage tank is provided at the bottom of the shaft, and the secondary crushing unit is provided at the bottom of the shaft and located above the bottom storage tank, and the secondary crushing unit is used to perform secondary crushing on the fluidized coal-water mixture, and the pumping unit is used to pump the fluidized coal-water mixture in the bottom storage tank that has been secondary crushed by the secondary crushing unit to the separation and collection unit, and the separation and collection unit is used to separate and collect coal, water and coalbed methane.

2. The in-situ coal and coalbed methane co-mining system suitable for soft coal seams according to claim 1 is characterized in that: The secondary crushing unit includes a bracket, a crushing bin, a feeding bin, a crushing mechanism and a crushing motor. The bracket is arranged above the bottom storage tank, the crushing bin is arranged on the bracket, the feeding bin is arranged on the top of the crushing bin, the crushing mechanism is arranged in the crushing bin, and the crushing motor is used to provide power to the crushing mechanism.

3. The in-situ coal and coalbed methane co-mining system suitable for soft coal seams according to claim 2 is characterized in that: The crushing mechanism comprises an active crushing roller and a driven crushing roller, both ends of the active crushing roller are rotatably mounted in the crushing bin, both ends of the driven crushing roller are rotatably mounted in the crushing bin, the driven crushing roller is meshed with the active crushing roller, and the crushing motor is used to drive the active crushing roller to rotate.

4. The in-situ coal and coalbed methane co-mining system applicable to soft coal seams according to claim 2 is characterized in that: The feed bin is an inverted cone structure, and the area of ​​the top of the feed bin is larger than the area of ​​the bottom of the shaft.

5. The in-situ coal and coalbed methane co-mining system applicable to soft coal seams according to claim 1 is characterized in that: It also includes a plurality of transfer storage tanks which are arranged in sequence from bottom to top above the bottom storage tank, and the plurality of transfer storage tanks are all arranged on the same side of the wellbore. The pumping unit includes a bottom pumping mechanism, a top pumping mechanism and an intermediate pumping mechanism. The bottom pumping mechanism is used to pump the fluidized coal-water mixture in the bottom storage tank to the adjacent transfer storage tank, the intermediate pumping mechanism is used to pump the fluidized coal-water mixture in the lower transfer storage tank of two adjacent transfer storage tanks to the upper transfer storage tank, and the top pumping mechanism is used to pump the fluidized coal-water mixture in the uppermost transfer storage tank to the separation and collection unit.

6. The in-situ coal and coalbed methane co-mining system applicable to soft coal seams according to claim 5 is characterized in that: The bottom pumping mechanism includes a bottom pumping pipe and a bottom particle pump arranged on the bottom pumping pipe, and the two ends of the bottom pumping pipe are respectively connected to the bottom storage tank and the adjacent transfer storage tank; the intermediate pumping mechanism includes an intermediate pumping pipe and an intermediate particle pump arranged on the intermediate pumping pipe, and the two ends of the intermediate pumping pipe are respectively connected to the two adjacent transfer storage tanks; the top pumping mechanism includes a top pumping pipe and a top particle pump arranged on the top pumping pipe, and the two ends of the top pumping pipe are respectively connected to the topmost transfer storage tank and the separation and collection unit.

7. The in-situ coal and coalbed methane co-mining system applicable to soft coal seams according to claim 1 is characterized in that: The excavation mechanism includes a cutter disc housing, a cutting cutter disc, a cutter disc drive assembly and a roller cutter group. The cutter disc housing is arranged at the front end of the shell, the cutting cutter disc is rotatably mounted at the front end of the cutter disc housing, the cutter disc drive assembly is arranged in the cutter disc housing and is used to drive the cutting cutter disc to rotate, the roller cutter group is arranged at the front end of the cutting cutter disc, a plurality of feed holes are arranged on the cutting cutter disc, and a plurality of mounting holes are arranged on the cutting cutter disc; the water jet mechanism includes a water supply assembly and a plurality of water jet nozzles, each of the mounting holes is provided with a water jet nozzle, the water supply assembly is arranged on the shell and is used to supply water to the water jet nozzles; a transmission chamber and a crushing chamber are arranged in sequence in the shell from front to back, the front end of the transmission chamber is connected to the outlet at the rear end of the cutter disc housing, one end of the transmission mechanism is installed in the cutter disc housing, and the other end is installed in the transmission chamber, the crushing mechanism is arranged in the crushing chamber, and the rear end of the shell is provided with a discharge port corresponding to the position of the crushing chamber.

8. A method for in-situ co-mining of coal and coalbed methane suitable for soft coal seams, characterized in that: The following steps are involved: Step 1: Based on the ground drilling project, a wellbore is excavated, the depth of the wellbore is greater than the depth of the coal seam, a well lifting system is built using the wellbore, and a bottom storage tank with a size greater than the diameter of the wellbore is excavated at the bottom of the wellbore to receive the fluidized coal-water mixture flowing back; Step 2: Install a secondary crushing unit above the bottom storage tank, and connect the pumping unit to the bottom storage tank and the separation and collection unit on the ground; Step 3: Before coal and coalbed methane mining operations, first deploy the roof stability monitoring unit; Step 4: Use the vertical shaft lifting system to transport the mining and crushing unit downward along the shaft to a position close to the top of the coal seam, with the front end of the mining and crushing unit facing the coal seam. After the mining mechanism of the mining and crushing unit contacts the coal seam, it cuts the coal seam along a certain upward coal mining route, and the cut coal body is then transported to the crushing mechanism at the rear end of the mining and crushing unit through the transmission mechanism for crushing. The crushed coal powder falls into the mining tunnel. The water sprayed by the water jet mechanism at the front end of the mining and crushing unit forms a water flow in the mining tunnel, which converts the coal powder into fluidized state. Driven by the water flow and the inclination of the mining tunnel, the fluidized coal-water mixture continuously flows to the rear of the mining until it flows to the shaft and falls. Step 5, the fluidized coal-water mixture falls into the secondary crushing unit for further crushing, and then falls into the bottom storage tank; Step 6: Use the pumping unit to transport the fluidized coal-water mixture in the bottom storage tank from the bottom of the well to the separation and collection unit on the ground for separation and collection.

9. The in-situ coal and coalbed methane co-mining method applicable to soft coal seams according to claim 8, characterized in that: In step 4, for the nearly horizontal coal seam, an upward mining method is adopted. During the mining process, the moving direction of the mining and crushing unit must form a certain angle with the upward inclination of the coal seam; For inclined coal seams, during mining, the mining and crushing unit moves in the same direction as the coal seam inclination, and mining is performed along the upward inclination of the coal seam; The mining is carried out in a roundabout way. In the same mining plane, the mining and crushing unit takes the boundary between the shaft and the coal seam as the starting point and starts to make an elliptical motion. When the mining and crushing unit returns to the shaft, the mining distance is expanded and the elliptical motion is continued. In this way, the cycle is repeated several times and returns to the starting point. For coal seams with a certain thickness, they are mined layer by layer from top to bottom. After a certain range of coal seams near the roof rock layer is mined, when the mining and crushing unit returns to the starting point, the vertical shaft lifting system is used to lower the mining and crushing unit for a distance, and mining is carried out again in the same roundabout mining method until it approaches the bottom rock layer.

10. The in-situ coal and coalbed methane co-mining method applicable to soft coal seams according to claim 8, characterized in that: In step 4, for the nearly horizontal coal seam, an upward mining method is adopted. During the mining process, the moving direction of the mining and crushing unit must form a certain angle with the upward inclination of the coal seam; For inclined coal seams, during mining, the mining and crushing unit moves in the same direction as the coal seam inclination, and mining is performed along the upward inclination of the coal seam; Mining is carried out using a forked mining method. Within the same mining plane, the mining and crushing unit takes the junction of the shaft and the coal seam as the starting point. The mining and crushing unit mines forward for a certain distance to form a main mining tunnel, and then makes a 1 / 4 elliptical motion to the left of the main mining tunnel. When the mining and crushing unit reaches the apex of the ellipse, the mining and crushing unit begins to rotate 90° to the right and mines forward for a certain distance. Then, the mining and crushing unit continues to rotate 90° to the right and makes a 1 / 4 elliptical motion along the previous mining trajectory. When the mining and crushing unit reaches the main mining tunnel, the mining and crushing unit continues to mine forward for a certain distance, and then makes a 1 / 4 elliptical motion to the left of the main mining tunnel. When the mining and crushing unit reaches the apex of the ellipse, the mining and crushing unit begins to rotate 90° to the right and mines forward for a certain distance. Then, the mining and crushing unit continues to rotate 90° to the right and makes a 1 / 4 elliptical motion along the previous mining trajectory. Make a 1 / 4 elliptical motion, and repeat this cycle several times; after mining forward for a distance along the inclination of the coal seam, return to the main mining tunnel, the mining and crushing unit starts to make a 1 / 4 elliptical motion to the right side of the main mining tunnel, when the mining and crushing unit reaches the apex of the ellipse, the mining and crushing unit rotates 90° to the right and mines a certain distance backward, then the mining and crushing unit continues to rotate 90° to the right and makes a 1 / 4 elliptical motion next to the previous mining trajectory, and when reaching the main mining tunnel, move backward for a certain distance along the main mining tunnel, the mining and crushing unit makes a 1 / 4 elliptical motion to the right side of the main mining tunnel, when the mining and crushing unit reaches the apex of the ellipse, the mining and crushing unit rotates 90° to the right and mines a certain distance backward, then the mining and crushing unit continues to rotate 90° to the right and makes a 1 / 4 elliptical motion next to the previous mining trajectory, and repeats this cycle several times until it reaches the starting position; For coal seams with a certain thickness, they are mined layer by layer from top to bottom. After a certain range of coal seams near the roof rock layer has been mined, when the mining and crushing unit returns to the starting point, the vertical shaft lifting system is used to lower the mining and crushing unit for a distance, and mining is carried out again using the same forked mining method until it approaches the bottom rock layer.

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