Pneumatic directional energy-gathering pulse device suitable for soft outburst coal seam

Abstract

The utility model relates to a pneumatic directional energy-gathered pulse device suitable for a soft and outburst coal seam, which comprises a mining anti-explosion air compressor, an air source triple piece, a sand injection port, a pneumatic pulse generator, a large-aperture hollow long drill rod and a self-rotating type energy-gathered jet drill bit, an air inlet pipe is arranged at one end of the mining anti-explosion air compressor, and an air outlet pipe is arranged at the other end of the mining anti-explosion air compressor. An air source triple piece is arranged at an air inlet of the air inlet pipe and comprises a pressure reducing valve, an air filter and an atomized lubricator; an air outlet pipe of the mining anti-explosion air compressor is provided with a pneumatic pulse generator and a sand injection port, and the sand injection port is used for injecting screened sand; the air outlet end of the mining anti-explosion air compressor is connected with the large-aperture hollow long drill rod, and the large-aperture hollow long drill rod is connected with the self-rotating type energy-gathering jet flow drill bit. The gas-sand multi-medium directional energy-gathering pulse anti-reflection mode is adopted, and efficient pressure relief and anti-reflection of the soft outburst coal seam are achieved through the synergistic process of high-pressure jet flow, coal body penetration and seam forming and maintaining.

Description

Technical Field

[0001] This utility model relates to the field of coal mine gas extraction technology, and in particular to a pneumatic directional energy-concentrating pulse device suitable for soft, outburst-prone coal seams, which is suitable for improving permeability and efficiently extracting gas from soft, outburst-prone coal seams with low permeability and easy collapse. Background Technology

[0002] my country's coal mine geological conditions vary greatly, with gas-bearing coal seams widely distributed and most exhibiting poor permeability. According to the "Detailed Rules for the Prevention and Control of Coal and Gas Outbursts," high-gas and coal and gas outburst mines require comprehensive prevention and control measures to reduce coal seam gas pressure and eliminate outburst risks; among these measures, coal seam permeability enhancement is widely used. However, conventional coal seam pre-extraction gas devices face challenges in my country's coal mining industry, including high ground stress, high gas pressure, high gas content, and low permeability. These issues make it difficult to maintain joints and prone to collapse in soft, outburst-prone coal seams, hindering gas control. Conventional permeability enhancement technologies also have the following problems:

[0003] (1) Conventional hydraulic fracturing device: requires a large amount of water, which can easily lead to coal body softening and hole collapse, and the crack closure speed is fast, resulting in poor crack preservation effect;

[0004] (2) Conventional pneumatic fracturing device: The energy of a single gaseous medium decays rapidly, making it difficult to form a stable fracture network;

[0005] (3) Chemical grouting device: high cost, high pollution risk, and serious damage to the original structure of coal.

[0006] Therefore, there is an urgent need for a pneumatic directional energy-concentrating pulse device suitable for soft, outburst-prone coal seams, which can improve the permeability of soft, outburst-prone coal seams while improving the gas extraction effect. Utility Model Content

[0007] The purpose of this invention is to overcome the above-mentioned shortcomings and provide a pneumatic directional energy-concentrating pulse device suitable for soft and protruding coal seams. It can utilize multiphase media to dynamically impact and mechanically support cracks, and is easy to operate, energy-saving and emission-reducing, pollution-reducing, safe and economical.

[0008] The purpose of this utility model is achieved as follows:

[0009] A pneumatic directional energy-concentrating pulse device suitable for soft, outburst-protruding coal seams includes a mine explosion-proof air compressor, an air source triplet, a sand injection port, a pneumatic pulse generator, a large-diameter hollow long drill rod, and a self-rotating energy-concentrating jet drill bit. The mine explosion-proof air compressor has an air inlet pipe at one end and an air outlet pipe at the other end. The end of the air inlet pipe is the air inlet, and the end of the air outlet pipe is the air outlet.

[0010] The mine explosion-proof air compressor is equipped with an air source triplet at the air inlet, which includes a pressure reducing valve, an air filter, and an oil mist lubricator. The air filter, pressure reducing valve, and oil mist lubricator are arranged sequentially between the air inlet and outlet of the air source triplet. The mine explosion-proof air compressor is also equipped with a safety valve and a solenoid pilot valve.

[0011] The outlet pipe of the mining explosion-proof air compressor is equipped with a pneumatic pulse generator and a sand injection port in sequence. The sand injection port is used to inject screened sand and gravel. The outlet end of the outlet pipe is connected to one end of a large-diameter hollow long drill rod, and the other end of the large-diameter hollow long drill rod is connected to a spin-type energy-concentrating jet drill bit.

[0012] Furthermore, the safety valve is located on the top surface of the mining explosion-proof air compressor, and the electromagnetic pilot valve can be located at any external position on the front, side, or bottom surface of the mining explosion-proof air compressor.

[0013] Furthermore, the end face of the spin-type focused jet drill bit is provided with multiple jet holes.

[0014] Furthermore, the sand and gravel particles injected through the sand injection port have a particle size of 0.5~0.8 mm.

[0015] Furthermore, the inner diameter of the large-diameter hollow long drill rod is not less than 50 mm.

[0016] Furthermore, the end face of the spin-type focused jet drill bit is provided with 3 to 6 jet holes for jetting both gas and sand / gravel media.

[0017] Furthermore, the diameter of the jet orifice is 0.5~1.0 mm.

[0018] Furthermore, the bottom of the mining explosion-proof air compressor is provided with multiple evenly distributed caster brackets, and the casters are connected through the caster brackets to facilitate the movement of the mining explosion-proof air compressor.

[0019] Furthermore, the pressure of the pneumatic pulse generator does not exceed 2 MPa.

[0020] Compared with the prior art, the beneficial effects of this utility model are:

[0021] This invention provides a pneumatic directional focused pulse device suitable for soft, outburst-prone coal seams. Addressing the difficulty of preserving fractures in soft, outburst-prone coal seams, it employs a gas-sand multi-media directional focused pulse permeation enhancement method. Through a synergistic process of "high-pressure jet - coal body penetration - fracture creation and preservation," it achieves permeability enhancement in soft, outburst-prone coal seams. The directional focused pulse device generates a gas-solid two-phase focused jet, forming a dynamic stress wave with alternating compression and tension within the coal body. This promotes the expansion of primary pores and the generation of micro-fractures. After continuous pulsating impact, it damages and disrupts the coal body surrounding the borehole, forming a network of interconnected fractures. Simultaneously, sand and gravel wedge into the fractures, restricting fracture closure and increasing gas migration pathways. Therefore, it achieves efficient pressure relief and permeability enhancement and gas extraction in soft, outburst-prone coal seams. Its operation is simple and has the following advantages:

[0022] (1) High efficiency permeability enhancement: Dynamic impact of gas-solid two-phase flow increases the crack propagation rate of coal body by 40%~60%, and sand and gravel support reduces the crack closure rate by more than 70%.

[0023] (2) Energy saving and emission reduction: Compared with hydraulic fracturing, it saves 100% of water and reduces energy consumption by 30%;

[0024] (3) High safety: Explosion-proof design avoids the risk of gas explosion;

[0025] (4) Wide adaptability: It is suitable for various soft and outburst-prone coal seams, especially for improving permeability and efficient gas extraction in soft and outburst-prone coal seams with low permeability and easy collapse. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of the pneumatic directional energy-concentrating pulse device of the present invention, which is applicable to soft and protruding coal seams.

[0027] Figure 2 This is a schematic diagram of the structure of the air source triple unit device of this utility model.

[0028] Figure 3 This is a schematic diagram of the structure of the spin-type focused jet drill bit of this utility model.

[0029] in:

[0030] Mining explosion-proof air compressor 1, safety valve 2, air source triplet 3, caster wheel 4, air inlet pipe 5.1, air outlet pipe 5.2, electromagnetic pilot valve 6, sand injection port 7, pneumatic pulse generator 8, large diameter hollow long drill rod 9, self-rotating energy jet drill bit 10, pressure reducing valve 11, air filter 12, oil mist lubricator 13, jet hole 14. Detailed Implementation

[0031] To better understand the technical solution of this utility model, a detailed description will be provided below in conjunction with relevant illustrations. It should be understood that the specific embodiments described below are not intended to limit the specific implementation of the technical solution of this utility model, but are merely possible implementations of the technical solution of this utility model. It should be noted that the descriptions of the positional relationships of the components herein, such as component A being located above component B, are based on the relative positions of the components in the illustrations and are not intended to limit the actual positional relationships of the components. Example 1

[0032] See Figures 1-3 , Figure 1 A schematic diagram of a pneumatic directional energy-concentrating pulse device suitable for soft, outburst-prone coal seams, as shown in Embodiment 1, is illustrated. As shown, this embodiment 1 involves a pneumatic directional energy-concentrating pulse device suitable for soft, outburst-prone coal seams, comprising a mine explosion-proof air compressor 1, an air source triplet 3, a sand injection port 7, a pneumatic pulse generator 8, a large-diameter hollow long drill rod 9, and a spin-type energy-concentrating jet drill bit 10. The mine explosion-proof air compressor 1 has an inlet pipe 5.1 at one end and an outlet pipe 5.2 at the other end. The end of the inlet pipe 5.1 is the air inlet, and the end of the outlet pipe 5.2 is the air outlet.

[0033] The mining explosion-proof air compressor 1 is equipped with a safety valve 2 and an electromagnetic pilot valve 6. The safety valve 2 is located on the top surface of the mining explosion-proof air compressor 1, and the electromagnetic pilot valve 6 can be located at any external position on the front, side or bottom surface of the mining explosion-proof air compressor 1.

[0034] The mine explosion-proof air compressor 1 is equipped with an air source triplet 3 at its air inlet. The air source triplet 3 includes a pressure reducing valve 11, an air filter 12, and an oil mist lubricator 13. The air filter 12, pressure reducing valve 11, and oil mist lubricator 13 are sequentially arranged between the air inlet and outlet of the air source triplet 3. The air source of the mine explosion-proof air compressor 1 first passes through the air filter 12, which is mainly responsible for filtering out impurities and moisture entering the air system and protecting downstream equipment from damage. Then, it passes through the pressure reducing valve 11, which adjusts the pressure of the purified compressed air to the stable pressure value required by the equipment to meet the normal working requirements of the pneumatic equipment. Finally, it passes through the oil mist lubricator 13, which atomizes the lubricating oil and mixes it into the compressed air to lubricate the moving parts of the mine explosion-proof air compressor 1. The air source triplet can effectively protect the pneumatic system, ensure its stable operation, and extend the service life of the equipment.

[0035] The outlet pipe 5.2 of the mining explosion-proof air compressor 1 is sequentially equipped with a pneumatic pulse generator 8 and a sand injection port 7. The sand injection port 7 is used to inject screened sand and gravel with a particle size of 0.5~0.8 mm. The pressure of the pneumatic pulse generator 8 does not exceed 2 MPa.

[0036] The air outlet end of the air outlet pipe 5.2 is connected to one end of the large-diameter hollow long drill rod 9, and the other end of the large-diameter hollow long drill rod 9 is connected to the self-rotating energy-concentrating jet drill bit 10.

[0037] The inner diameter of the large-diameter hollow long drill rod 9 is ≥50 mm, and the self-rotating energy jet drill bit 10 can rotate at high speed, with a rotation speed of 50~100 rpm.

[0038] The end face of the spin-type focused jet drill bit 10 is provided with 3 to 6 jet holes 14 for jetting both gas and sand / gravel media. The diameter of the jet holes 14 is 0.5 to 1.0 mm.

[0039] The bottom of the mining explosion-proof air compressor 1 is provided with multiple evenly distributed caster brackets, and casters 4 are connected to the caster brackets to facilitate the movement of the mining explosion-proof air compressor 1.

[0040] This embodiment 1 relates to a method for enhancing the permeability of a pneumatic directional focused pulse device suitable for soft, outburst-protruding coal seams, which includes the following:

[0041] S1. Drilling construction;

[0042] In the soft, outburst-protruding coal seam roadway, in-seam drilling was carried out on both sides of the roadway, with a drilling diameter of 89 mm.

[0043] Drill different distances according to the differences in coal seam firmness coefficient, permeability, etc., to form reserved boreholes, and then withdraw the drill rod and drill bit;

[0044] S2. Device installation;

[0045] A large-diameter hollow long drill rod and a self-rotating energy-concentrating jet drill bit placed at the end of the drill rod are fed into the reserved borehole. After the drill rod is fed to a certain length, the mine explosion-proof air compressor, air source triplet, electromagnetic pilot valve and pneumatic pulse generator are started.

[0046] S3, Gas source treatment;

[0047] The air source required for this device is first injected into the air supply triplet. After being stabilized, cleaned, and lubricated by the air supply triplet, the air is then input into the air compressor to form high-pressure air; the details are as follows:

[0048] The air injection triplet consists of an air filter that filters moisture from the air, a pressure reducing valve that adjusts the outlet pressure using a flexible element, an oil mist lubricator that adds oil mist to the compressed air, a pressure reducing valve that acts as a lubricant for pneumatic components, and a pressure reducing valve that stabilizes the air supply pressure to maintain a constant level, reducing damage to valves or actuators caused by sudden changes in air pressure. The filter cleans the air supply, removing moisture from the compressed air to prevent it from entering the device. The oil mist lubricates moving parts and components where lubrication is inconvenient. After being stabilized, cleaned, and lubricated by the triplet, the air is fed into the air compressor to form high-pressure air.

[0049] S4. Compressed air is input to the solenoid pilot valve, and after being stabilized by the solenoid pilot valve, it is output to the pulse generator.

[0050] The operation process of the electromagnetic pilot valve: The electromagnetic pilot valve operates synchronously. When the electromagnetic valve coil is energized, the electromagnetic force generated is greater than the air source pressure. The moving block and the guide sleeve are attracted to open the pilot overflow hole. The air in the upper chamber of the piston flows to the outlet through the overflow hole. At this time, the air pressure in the upper chamber of the piston will be lower than the inlet air pressure. The pressure difference causes the piston to move and separate from the valve port. Then the main valve port opens and the air flows from the inlet to the outlet.

[0051] S5, pulse loading;

[0052] The pneumatic pulse generator automatically generates pulse waves using air supplied by an explosion-proof air compressor, providing the power required for suture filling and permeation enhancement; the air pressure output by the pulse generator can reach 2 MPa.

[0053] S6, Sand injection;

[0054] After being preheated by an air compressor and a pneumatic pulse generator, the screened sand and gravel are injected into the sand injection port. Under the pressure of high-pressure air, the sand and gravel flow through the large-diameter hollow long drill rod to the self-rotating energy-concentrating jet drill bit.

[0055] S7, jet-assisted joint creation;

[0056] Driven by compressed air, sand and gravel flow to the drill rod and then to the drill bit. Due to the multiple jet holes on the end face of the drill bit, under the drive of high-pressure air, the high-pressure gas-solid two-phase flow of gas and sand is sprayed into the coal body around the borehole through the energy-concentrating effect of the jet holes of the spin-type energy-concentrating jet drill bit.

[0057] Under the penetration of high-pressure gas-solid two-phase flow, soft coal body forms a network of fractures; under the rotation of the spin drill bit, sand and gravel are densely wedged into the coal body fractures in the form of rotating cross sections, supporting the expansion of fractures.

[0058] S8. Repetitive tasks;

[0059] Repeat the above steps and construct at different locations in the borehole to form a network of developed fractures with the borehole as the axis, thus providing a guarantee for gas extraction.

[0060] S9, Gas extraction;

[0061] After the entire coal section is completed, the equipment is removed, the boreholes are sealed, and the gas extraction system is connected for gas extraction.

[0062] The above-mentioned pneumatic directional energy-concentrating pulse device, applicable to soft and outburst-prone coal seams, was implemented in a certain mine, and the following implementation data were obtained:

[0063] The mine-use explosion-proof air compressor outputs a pressure of 1.8 MPa, which is stabilized to 1.5 MPa by the air source triplet; the electromagnetic pilot valve controls the pulse generator to output pulse waves at a frequency of 15 Hz; 0.6 mm quartz sand is injected into the sand injection port, mixed with compressed air, and then transported to the drill bit through the drill rod; the drill bit rotates at 80 rpm, and the jet hole sprays air and sand to impact the coal body, forming radial cracks with a depth of ≥2m.

[0064] Implementation method: Drill holes in coal seams with a firmness coefficient of 0.3, with a single-stage impact time of 3 to 5 minutes;

[0065] Repeated impact 2-3 times per meter of borehole increased the fracture network permeability to 0.5 mD (original value 0.02 mD).

[0066] After 30 days of extraction, the gas concentration dropped from 8% to 0.5%, and the extraction efficiency increased fourfold.

[0067] Working principle:

[0068] This utility model provides a pneumatic directional energy-concentrating pulse device suitable for soft, outburst-protruding coal seams, comprising the following core components:

[0069] (1) Explosion-proof air compressor for mining: provides high-pressure air source (pressure ≤2 MPa);

[0070] (2) Air source triple unit: integrates pressure reducing valve, air filter and oil mist lubricator to achieve air source pressure stabilization, water removal and lubrication;

[0071] (3) Pneumatic pulse generator: controlled by an electromagnetic pilot valve, it generates periodic pulse waves (frequency 10~20 Hz).

[0072] (4) Large-diameter hollow long drill rod (inner diameter ≥ 50 mm): for conveying gas-sand mixed medium;

[0073] (5) Spin-type focused jet drill bit: The end is provided with 3 to 6 jet holes with a diameter of 0.5 to 1.0 mm, which can rotate at high speed (50 to 100 rpm).

[0074] (6) Sand injection port: Inject sieved sand and gravel with a particle size of 0.5~0.8 mm as crack proppant.

[0075] This utility model provides a method for enhancing the permeability of a pneumatic directional focusing pulse device suitable for soft, outburst-protruding coal seams, comprising the following steps:

[0076] Drilling operations: Drill holes (89 mm in diameter) along the coal seam on both sides of the roadway, adjusting the drilling depth according to the coal seam parameters;

[0077] Device installation: Send the drill rod and the self-rotating drill bit into the borehole, and connect the air source triplet, pulse generator and sand injection port;

[0078] Air source treatment: Compressed air is input to the pulse generator after being stabilized, filtered, and lubricated;

[0079] Pulse loading and sand injection: Start the pulse generator and inject sand and gravel synchronously to form a high-pressure gas-solid two-phase flow;

[0080] Jet fracture formation: Sand and gravel are concentrated and injected at the jet hole of the drill bit, impacting the coal body to form fractures, and the fractures are supported by rotating wedging.

[0081] Repeated work: Segmented construction along the borehole axis to form a continuous fracture network;

[0082] Gas extraction: After construction is completed, the borehole is sealed and connected to the extraction system.

[0083] This utility model discloses a pneumatic directional energy-concentrating pulse device suitable for soft, outburst-protruding coal seams, which has the following core innovative features:

[0084] (1) Gas-sand multiphase synergy: High-pressure air and sand form a gas-solid two-phase flow. Through the pulse impact and rotational wedging support of the gas-sand two-phase flow, a network of through-cracks is formed in the soft coal seam; it has both kinetic energy impact and mechanical support.

[0085] (2) Spinning drill bit design: The jet holes are spirally distributed, and the jet penetration range is enhanced by rotation;

[0086] (3) Pulse dynamic loading: Periodic pulse waves generate alternating compressive and tensile stress, which promotes the connection of crack networks.

[0087] The above are merely specific application examples of this utility model and do not constitute any limitation on the scope of protection of this utility model. All technical solutions formed by equivalent transformations or equivalent substitutions fall within the scope of protection of this utility model.

Claims

1. A pneumatic directional shaped charge pulse device suitable for use in soft and outburst coal seams, characterized in that: It comprises a mine explosion-proof air compressor (1), a gas source triplex (3), a sand injection port (7), a pneumatic pulse generator (8), a large-aperture hollow long drill rod (9) and a self-rotating energy-gathering jet drill bit (10), one end of the mine explosion-proof air compressor (1) is provided with an air inlet pipe (5.1), the other end is provided with an air outlet pipe (5.2), the end of the air inlet pipe (5.1) is an air inlet, the end of the air outlet pipe (5.2) is an air outlet. The air inlet of the mine explosion-proof air compressor (1) is provided with a gas source triplex (3), the gas source triplex (3) comprises a pressure reducing valve (11), an air filter (12) and an oil atomizer (13), the air filter (12), the pressure reducing valve (11) and the oil atomizer (13) are sequentially arranged between the air inlet and the air outlet of the gas source triplex (3); the mine explosion-proof air compressor (1) is further provided with a safety valve (2) and an electromagnetic pilot valve (6); The air outlet pipe (5.2) of the mine explosion-proof air compressor (1) is sequentially provided with a pneumatic pulse generator (8) and a sand injection port (7), the sand injection port (7) is used for injecting screened sand and gravel; one end of the air outlet pipe (5.2) is connected with one end of the large-aperture hollow long drill rod (9), the other end of the large-aperture hollow long drill rod (9) is connected with the self-rotating energy-gathering jet drill bit (10).

2. The device according to claim 1, characterized in that: The safety valve (2) is arranged on the top surface of the mine explosion-proof air compressor (1), and the electromagnetic pilot valve (6) can be arranged at any external position on the front surface, the side surface or the bottom surface of the mine explosion-proof air compressor (1).

3. The device according to claim 1, characterized in that: the device is suitable for soft and protruding coal seam. The end surface of the self-rotating energy-gathering jet drill bit (10) is provided with a plurality of jet holes (14).

4. The device according to claim 1, characterized in that: The sand and gravel injected by the sand injection port (7) has a particle size of 0.5-0.8 mm.

5. The device according to claim 1, characterized in that: The inner diameter of the large-aperture hollow long drill rod (9) is not less than 50 mm.

6. The device according to claim 3, characterized in that: The end surface of the self-rotating energy-gathering jet drill bit (10) is provided with 3-6 jet holes (14) for jetting gas and sand and gravel.

7. The device according to claim 6, characterized in that it is suitable for use in soft and outburst coal seams. The jet hole (14) has a diameter of 0.5-1.0 mm.

8. The device according to claim 1, characterized in that it is suitable for soft and protruding coal seams. A plurality of universal wheel supports are evenly arranged below the bottom of the mine explosion-proof air compressor (1), a universal wheel (4) is connected through the universal wheel support, so that the mine explosion-proof air compressor (1) can be easily moved.

9. The device according to claim 1, characterized in that it is suitable for soft and outburst coal seams. The pressure of the pneumatic pulse generator (8) is not more than 2 MPa.

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