Hole sealing injection device and method for gas extraction hole

Abstract

The invention discloses a hole sealing injection device and method for a gas extraction hole, and belongs to the field of gas extraction. The first end of a CO2 gas injection pipe of the device is communicated with a CO2 gas cylinder, and a gas diffuser is fixedly arranged at the second end of the CO2 gas injection pipe; a gas cylinder valve, a pressure gauge, a pressure reducing valve and a mass flow controller are sequentially arranged on the CO2 gas injection pipe in the direction from the CO2 gas cylinder to the gas diffuser; the first end of the grouting pipe communicates with the slurry preparation mechanism, and the second end of the grouting pipe communicates with the hole sealing mechanism. The gas diffuser is communicated with the outer wall of the grouting pipe, and an obtuse angle is formed between the grouting pipe and the central axis of the CO2 gas injection pipe in the clockwise direction; the slurry preparation mechanism is used for stirring coal-based solid waste powder, hole sealing cement and water to obtain negative carbon slurry, conveying the negative carbon slurry to a grouting pipe, mixing the negative carbon slurry with CO2 micron bubbles to obtain hole sealing slurry, and conveying the hole sealing slurry to the hole sealing mechanism; and the hole sealing mechanism is arranged in the gas extraction hole. The device can be suitable for a closed environment, and the strength and the sealing performance of the internal gas extraction hole are improved.

Description

Technical Field

[0001] This application relates to the field of gas extraction technology, and in particular to a sealing injection device and method for gas extraction holes. Background Technology

[0002] In the field of coal mine gas drainage, the sealing quality of gas drainage holes directly affects drainage efficiency and mine safety. The core of this application scenario lies in the sealing material's ability to withstand the complex stress environment underground, ensuring effective isolation and extraction of gas. Meanwhile, against the backdrop of global "dual carbon" goals, CO2 sequestration has become an important direction for achieving low-carbon and green mining development. This emphasizes that the sealing process should not only improve structural strength but also achieve CO2 mineralization and sequestration, as well as solid waste reuse, thus achieving both environmental and economic benefits.

[0003] In existing technologies, gas drainage borehole sealing primarily utilizes cement-based sealing materials, filling the borehole through external grouting to form a physical isolation barrier. These materials rely on traditional curing mechanisms, resulting in limited density and stress resistance. While effective in shallow mines, they struggle to withstand the high stress conditions of deep mines. When coal seam stress is high, the sealing material is prone to cracking, leading to sealing failure and increased gas leakage risks. Furthermore, to improve the compressive strength of cement materials, some technologies have attempted external CO2 gas curing methods, introducing CO2 gas into the curing environment to enhance material density and durability. This method is used in open areas, but its core relies on an external gas supply system. Once the sealing grout is injected into the gas drainage borehole, the enclosed environment and limited ventilation prevent effective external CO2 gas curing.

[0004] Existing technologies have significant drawbacks. First, cement-based sealing materials lack sufficient density and stress resistance, making them prone to cracking under the high ground stress of deep mines, leading to sealing failure and increased risk of gas leakage. Second, external CO2 curing methods are limited by the closed borehole environment and cannot be implemented inside gas extraction holes. This prevents the CO2 carbonization reaction from occurring during the slurry solidification process, thus failing to improve the strength and sealing performance of the internal gas extraction holes. Summary of the Invention

[0005] This application provides a sealing injection device and method for gas extraction holes, which can solve the problems that existing cement-based sealing materials are prone to sealing failure and increased risk of gas leakage, and that external CO2 curing methods are not suitable for closed environments and cannot improve the strength and sealing performance of internal gas extraction holes.

[0006] To achieve the above objectives, the technical solution of this invention is as follows:

[0007] In a first aspect, embodiments of the present invention provide a sealing and injection device for a gas extraction hole, comprising a CO2 cylinder, a cylinder valve, a pressure gauge, a CO2 gas injection pipe, a pressure reducing valve, a mass flow controller, a gas diffuser, a slurry preparation mechanism, a grouting pipe, and a sealing mechanism;

[0008] The gas diffuser includes a cylinder and a diffuser plate, and the diffuser plate has a plurality of through holes evenly distributed on it.

[0009] The first end of the CO2 gas injection pipe is connected to the output port of the CO2 gas cylinder, and the second end is fixed to the first end of the gas diffuser where the diffuser plate is located.

[0010] The CO2 gas injection pipe is provided with the gas cylinder valve, the pressure gauge, the pressure reducing valve and the mass flow controller in sequence along the direction from the CO2 gas cylinder to the gas diffuser;

[0011] The first end of the grouting pipe is connected to the output port of the grout preparation mechanism, and the second end is connected to the sealing mechanism.

[0012] The second end of the gas diffuser is connected to the outer wall of the grouting pipe, and the central axis of the grouting pipe is at an obtuse angle to the central axis of the second end of the CO2 gas injection pipe in a clockwise direction, so as to deliver CO2 micron bubbles to the grouting pipe;

[0013] The slurry preparation mechanism is used to mix coal-based solid waste powder, sealing cement and water in a preset ratio to obtain negative carbon slurry, which is then transported to the grouting pipe. The negative carbon slurry is then mixed with CO2 micron bubbles to obtain sealing slurry, which is then transported to the sealing mechanism.

[0014] The sealing mechanism is installed inside the gas extraction hole and is used to seal the gas extraction hole after the sealing slurry is introduced.

[0015] In conjunction with the first aspect, in one possible implementation, the slurry preparation mechanism includes a mixing tank, a stirrer, and a slurry pump;

[0016] The stirrer is inserted into the mixing tank;

[0017] The grouting pump is mounted on the mixing tank, with its inlet located inside the mixing tank and its outlet connected to the first end of the grouting pipe.

[0018] In conjunction with the first aspect, in one possible implementation, the sealing mechanism includes a sealing bladder and a burst valve;

[0019] The second end of the grouting pipe is inserted into the gas extraction hole;

[0020] The sealing bag includes two bags, which are fitted at a predetermined distance to the second end of the grouting pipe and are both connected to the grouting pipe and located inside the gas extraction hole.

[0021] The burst valve is located on the grouting pipe between the two sealing bags.

[0022] In conjunction with the first aspect, in one possible implementation, the sealing injection device for the gas extraction hole also includes a backwash pipe, a backwash valve, a three-way valve, and a waste discharge pipe;

[0023] The first end of the backwash pipe is fed with the cleaning medium, and the second end is connected to the side wall of the CO2 gas injection pipe between the mass flow controller and the gas diffuser.

[0024] The first end of the three-way valve is connected to the second end of the gas diffuser, the second end is connected to the grouting pipe, and the third end is connected to the first end of the waste discharge pipe.

[0025] In conjunction with the first aspect, in one possible implementation, the sealing injection device for the gas extraction hole also includes an adjustable elbow mechanism, an electric actuator, a control mechanism, and a slurry viscosity sensor.

[0026] The adjustable elbow mechanism includes a hinged elbow and a ball joint.

[0027] The hinged elbow includes a connecting pipe and a ball joint;

[0028] The first end of the connecting pipe is fixedly connected to the second end of the gas diffuser;

[0029] The ball head is fixed at the second end of the connecting pipe, and the inner cavity of the connecting pipe and the ball head is a smooth flow channel;

[0030] The inner cavity of the ball joint is a ball cavity adapted to the ball head, and a through hole is provided at the bottom, which is fixed to the outer wall of the grouting pipe;

[0031] The ball head is nested within the ball socket joint;

[0032] The slurry viscosity sensor is disposed in the slurry preparation mechanism and electrically connected to the control mechanism, and is used to measure the viscosity value of the negative carbon slurry prepared by the slurry preparation mechanism and transmit the viscosity value to the control mechanism;

[0033] The output end of the electric actuator is connected to the connecting pipe and electrically connected to the control mechanism. The control mechanism controls the working state of the electric actuator according to the viscosity value so that the electric actuator drives the hinged elbow to rotate around the ball joint, thereby adjusting the obtuse angle between the grouting pipe and the CO2 gas injection pipe in real time.

[0034] In conjunction with the first aspect, in one possible implementation, both the mass flow controller and the slurry preparation mechanism are electrically connected to the control mechanism.

[0035] Secondly, embodiments of the present invention provide a sealing injection method for gas extraction holes, based on the aforementioned sealing injection device for gas extraction holes, comprising:

[0036] Step 1: Mix coal-based solid waste powder, sealing cement, and water in a slurry preparation device according to a preset ratio to obtain negative carbon slurry;

[0037] Step 2: Open the CO2 cylinder. The CO2 cylinder outputs CO2 gas to the CO2 gas injection pipe. The gas pressure and flow rate of the CO2 gas are jointly regulated by the cylinder valve, pressure gauge, pressure reducing valve and mass flow controller to form a stable CO2 gas flow to the gas diffuser. The gas diffuser decomposes the CO2 gas into CO2 micron bubbles.

[0038] Step 3: The slurry preparation mechanism delivers the prepared negative carbon slurry to the grouting pipe, and the gas diffuser inputs the CO2 microbubbles into the grouting pipe. The central axis of the grouting pipe and the central axis of the second end of the CO2 gas injection pipe form an obtuse angle in the clockwise direction, so that the high-speed flowing negative carbon slurry generates a shearing effect on the airflow of the CO2 microbubbles. The negative carbon slurry and the CO2 microbubbles are uniformly mixed in the grouting pipe to obtain a sealing slurry.

[0039] Step 4: The sealing grout is fed into the sealing mechanism through the grouting pipe. The sealing mechanism is set inside the gas extraction hole. After the sealing grout is fed into the sealing mechanism, the gas extraction hole is sealed.

[0040] In conjunction with the second aspect, in one possible implementation, step 1 includes: mixing the nanoscale carbonization reaction catalyst with coal-based solid waste powder, sealing cement and water in the slurry preparation device in a preset ratio.

[0041] In conjunction with the second aspect, in one possible implementation, the method further includes the following step before step 1:

[0042] Step A1: Crush and grind the coal-based solid waste raw material to obtain coal-based solid waste pre-material with a particle size of less than 75μm;

[0043] Step A2: Activate the coal-based solid waste feedstock to obtain a coal-based solid waste mixture, wherein the activation treatment includes at least one of chemical activation or biological activation;

[0044] Step A3: Separate the coal-based solid waste mixture into solid and liquid components, and dry the solid product to obtain coal-based solid waste powder.

[0045] In conjunction with the second aspect, in one possible implementation, in step A2, the chemical activation includes leaching treatment with a dilute acid solution of concentration 15-5%;

[0046] The bioactivation includes treatment using microbial fermentation or bioleaching methods.

[0047] One or more technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages:

[0048] The sealing injection device for gas extraction holes provided in this application embodiment involves the following steps: Upon startup, a CO2 cylinder releases gas. The gas flow is initially controlled by a cylinder valve, and a pressure gauge monitors the output pressure in real time to ensure safety. Next, the CO2 gas flows through a pressure reducing valve to reduce its pressure to the working range. A mass flow controller then precisely adjusts the flow rate, creating a stable gas flow into the gas diffuser. The gas diffuser utilizes multiple through-holes on its diffuser plates to initially decompose the CO2 gas into micron-sized bubbles. Simultaneously, a slurry preparation mechanism mixes coal-based solid waste powder, sealing cement, and water in a preset ratio to form a uniform negative carbon slurry, which is then conveyed to the injection pipe. Because the central axis of the injection pipe is designed at an obtuse angle to the central axis of the second end of the CO2 gas injection pipe, the high-speed flowing negative carbon slurry shears the CO2 micron-sized bubble flow, further refining the bubble size and ensuring thorough mixing within the injection pipe to form a uniform sealing slurry. This sealing slurry is then conveyed to a sealing mechanism located within the gas extraction hole to achieve the filling and sealing operation of the gas extraction hole. The device in this embodiment converts CO2 gas into microbubbles and mixes them directly with negative carbon slurry inside the grouting pipe, achieving uniform carbonization curing inside the gas extraction borehole. The CO2 microbubbles are gradually released in the closed borehole environment, reacting with the coal-based solid waste powder and calcium minerals in the sealing cement to generate stable crystals such as calcium carbonate. This significantly improves the compressive strength and density of the sealing body, avoiding the risk of sealing failure and gas leakage caused by the cracking of existing cement-based materials under high stress in deep mines. The device in this embodiment does not rely on an external CO2 ventilation system, overcoming the limitation of external curing methods in closed borehole environments. Through the internal microbubble dispersion mechanism, it ensures efficient carbonization reaction during slurry solidification, thereby enhancing the long-term sealing performance of the sealing structure. Furthermore, combined with the reuse of coal-based solid waste, the device achieves synergistic benefits of CO2 mineralization and solid waste resource utilization while improving sealing quality, offering advantages such as simple process and high reliability. Attached Figure Description

[0049] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0050] Figure 1 This is a schematic diagram of the sealing injection device for gas extraction holes provided in an embodiment of this application.

[0051] Icons: 1-CO2 gas cylinder; 2-Cylinder valve; 3-Pressure gauge; 4-CO2 gas injection pipe; 41-First injection sub-pipe; 42-Second injection sub-pipe; 5-Pressure reducing valve; 6-Mass flow controller; 7-Gas diffuser; 71-Cylinder; 72-Diffuser; 8-Slurry preparation mechanism; 81-Mixing tank; 82-Agitator; 83-Grouting pump; 9-Grouting pipe; A-Sealing mechanism; A1-Perforated bag; A2-Break valve; B-Gas extraction hole. Detailed Implementation

[0052] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0053] In the description of the embodiments of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the embodiments of the present invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. The terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention according to the specific circumstances.

[0054] Please refer to Figure 1As shown, this embodiment of the invention provides a sealing injection device for a gas extraction hole, including a CO2 cylinder 1, a cylinder valve 2, a pressure gauge 3, a CO2 gas injection pipe 4, a pressure reducing valve 5, a mass flow controller 6, a gas diffuser 7, a slurry preparation mechanism 8, a grouting pipe 9, and a sealing mechanism A.

[0055] The gas diffuser 7 includes a cylinder 71 and a diffuser plate 72, on which multiple through holes are evenly distributed.

[0056] The first end of the CO2 gas injection pipe 4 is connected to the output port of the CO2 cylinder 1, and the second end is fixed to the first end of the diffuser plate 72 of the gas diffuser 7. The CO2 cylinder 1 is used to store and provide high-purity CO2 gas and is the main supply mechanism for CO2 gas in the system.

[0057] The CO2 gas injection pipe 4 is sequentially equipped with a gas cylinder valve 2, a pressure gauge 3, a pressure reducing valve 5, and a mass flow controller 6 along the direction from the CO2 gas cylinder 1 to the gas diffuser 7. The first end of the grouting pipe 9 is connected to the output port of the grout preparation mechanism 8, and the second end is connected to the sealing mechanism A. The second end of the gas diffuser 7 is connected to the outer wall of the grouting pipe 9, and the central axis of the grouting pipe 9 forms an obtuse angle with the central axis of the second end of the CO2 gas injection pipe 4 in a clockwise direction, so as to deliver CO2 micron-sized bubbles to the grouting pipe 9. Preferably, this obtuse angle is 110° to 135° to ensure that the negative carbon slurry generates sufficient shear force on the CO2 micron-sized bubble flow.

[0058] like Figure 1 As shown, the CO2 gas injection pipe 4 includes a first injection sub-pipe 41 and a second injection sub-pipe 42. The first end of the first injection sub-pipe 41 is connected to the output port of the CO2 cylinder 1, and the second end is connected to the first end of the second injection sub-pipe 42. One end of the diffuser 7's diffuser plate 72 is fixed to the second end of the second injection sub-pipe 42. A cylinder valve 2 and a pressure gauge 3 are sequentially installed along the direction from the CO2 cylinder 1 to the second injection sub-pipe 42 on the first injection sub-pipe 41. A pressure reducing valve 5 and a mass flow controller 6 are sequentially installed along the direction from the first injection sub-pipe 41 to the gas diffuser 7 on the second injection sub-pipe 42. The central axis of the first injection sub-pipe 41 and the central axis of the second injection sub-pipe 42 form an acute angle counterclockwise. The central axis of the grouting pipe 9 and the central axis of the second injection sub-pipe 42 form an obtuse angle clockwise. Figure 1 As shown, the first injection sub-pipe 41 is parallel to the grouting pipe 9.

[0059] Furthermore, the inlet of cylinder valve 2 is connected to the outlet of CO2 cylinder 1, and the outlet is connected to the inlet of pressure gauge 3 via the first injection sub-pipe 41 for controlling gas delivery. The outlet of pressure gauge 3 is connected to the inlet of pressure reducing valve 5 via the first injection sub-pipe 41 and the second injection sub-pipe 42 connected in sequence for real-time monitoring of the output pressure of CO2 gas, ensuring the safety and stability of CO2 gas supply. CO2 gas injection pipe 4 (including the first injection sub-pipe 41 and the second injection sub-pipe 42) is used to deliver CO2 gas released from CO2 cylinder 1 to gas diffuser 7. Pressure reducing valve 5 is installed on the second injection sub-pipe 42, and its outlet is connected to the inlet of mass flow controller 6 via the second injection sub-pipe 42 for reducing the pressure of high-pressure CO2 gas in the cylinder to the required operating pressure range of the device. The mass flow controller 6 is installed on the second injection sub-pipe 42, and its output port is connected to the input port of the gas diffuser 7 through the second injection sub-pipe 42. It is used to precisely control the flow rate of CO2 gas to ensure stable CO2 gas delivery, controllable flow rate, and matching injection rate with the flow rate of negative carbon slurry.

[0060] The gas diffuser 7 is located at the end of the CO2 gas injection pipe 4 (second injection sub-pipe 42) and merges with the grouting pipe 9. It is the core component for realizing the micronization of CO2 gas. The multiple through holes on the diffuser plate 72 of the gas diffuser 7 have a micron-sized pore structure. It first initially disperses the CO2 gas into CO2 micron-sized bubbles. Since the central axis of the grouting pipe 9 and the central axis of the second end of the CO2 gas injection pipe 4 form an obtuse angle in the clockwise direction, the negative carbon slurry and the CO2 micron-sized bubbles generate a shearing action at the confluence of the pipes. Under the shearing action, the CO2 micron-sized bubbles are further refined, resulting in CO2 micron-sized bubbles with uniform particle size and high stability. These bubbles are then introduced into the negative carbon slurry, thereby significantly improving the dispersion and reaction contact area of ​​CO2 gas in the negative carbon slurry.

[0061] The gas diffuser 7 is made of porous sintered stainless steel, which has the characteristics of high strength, corrosion resistance, uniform pore distribution and strong anti-clogging ability. It is not easy for the performance to be degraded due to the inflow of negative carbon slurry, solid particles or carbonized deposits in the negative carbon slurry.

[0062] The slurry preparation mechanism 8 is used to mix coal-based solid waste powder, sealing cement and water in a preset ratio to obtain negative carbon slurry, which is then transported to the grouting pipe 9. The negative carbon slurry is then mixed with CO2 micron bubbles to obtain sealing slurry, which is then transported to the sealing mechanism A.

[0063] Sealing mechanism A is installed inside gas drainage hole B and is used to seal gas drainage hole B after the sealing slurry is introduced. Gas drainage hole B is a horizontal borehole in the coal seam and is the target of this sealing device, used to inject sealing slurry and realize the internal carbonization sealing reaction.

[0064] The sealing injection device for gas extraction holes provided in this application embodiment involves the following steps: Upon startup, CO2 cylinder 1 releases gas, and the gas flow is initially controlled by cylinder valve 2. Pressure gauge 3 monitors the output pressure in real time to ensure safety. Next, the CO2 gas flows through pressure reducing valve 5 to reduce its pressure to the working range, and then the flow rate is precisely adjusted by mass flow controller 6 to form a stable airflow into gas diffuser 7. Gas diffuser 7 utilizes multiple through-holes on its diffuser plate 72 to initially decompose the CO2 gas into micron-sized bubbles. Simultaneously, slurry preparation mechanism 8 mixes coal-based solid waste powder, sealing cement, and water in a preset ratio to form a uniform negative carbon slurry, which is then conveyed to injection pipe 9. Because the central axis of injection pipe 9 is designed at an obtuse angle to the central axis of the second end of CO2 gas injection pipe 4, the high-speed flowing negative carbon slurry shears the CO2 micron-sized bubble flow, further refining the bubble particle size and ensuring thorough mixing within injection pipe 9 to form a uniform sealing slurry. The sealing slurry is then transported to the sealing mechanism A located within the gas extraction hole B, enabling the filling and sealing of the gas extraction hole B. The device in this embodiment achieves uniform carbonization curing inside the gas extraction hole B by converting CO2 gas into microbubbles and mixing them directly with the negative carbon slurry within the injection pipe 9. The CO2 microbubbles are gradually released in the closed borehole environment, reacting with the coal-based solid waste powder and calcium minerals in the sealing cement to generate stable crystals such as calcium carbonate. This significantly improves the compressive strength and density of the sealing body, avoiding the risk of sealing failure and gas leakage caused by the easy cracking of existing cement-based materials under high stress in deep mines. The device in this embodiment does not rely on an external CO2 ventilation system, overcoming the limitation of external curing methods being unusable in closed borehole environments. Through the internal microbubble dispersion mechanism, it ensures that the carbonization reaction occurs efficiently during the slurry solidification process, thereby enhancing the long-term sealing performance of the sealing structure. In addition, by combining the reuse of coal-based solid waste, the device improves the sealing quality and achieves synergistic benefits of CO2 mineralization and storage and solid waste resource utilization, with the advantages of simple process and safety and reliability.

[0065] Coal mining generates a large amount of coal-based solid waste. The device described in this application can effectively utilize this solid waste, reducing environmental pollution and improving resource utilization. CO2 gas can react with the calcium ore components in the solid waste and cement to generate calcium carbonate. Through this process, the internal structure of the cement is strengthened, and its density and compressive strength are significantly improved, thereby enhancing the durability and stability of the sealing cement and ensuring the longevity of the sealing effect. By diffusing CO2 gas to form micron-sized bubbles and injecting them together with the negative carbon slurry, the dispersion and reaction contact area of ​​CO2 gas in the negative carbon slurry can be significantly improved, making CO2 gas more effective. 2气体During the solidification process of the sealing slurry, uniform carbonization and curing are achieved from inside the hole, thereby forming a sealing body with higher strength and better density in the gas extraction hole B. This not only improves the sealing effect but also achieves the synergistic benefits of CO2 sequestration and solid waste resource utilization.

[0066] The slurry preparation mechanism 8 includes a mixing tank 81, a stirrer 82, and a grouting pump 83. The stirrer 82 is inserted into the mixing tank 81. The grouting pump 83 is mounted on the mixing tank 81, with its inlet located inside the mixing tank 81 and its outlet connected to the first end of the grouting pipe 9.

[0067] The mixing tank 81 is used to add coal-based solid waste powder, sealing cement, and water in proportion, and after thorough mixing, a uniform negative carbon slurry is formed as the sealing slurry. The agitator 82 is used to provide mechanical stirring power to ensure that the coal-based solid waste powder, sealing cement, and water are fully mixed to obtain a uniform and fluid negative carbon slurry. The grouting pump 83 is used to output the prepared negative carbon slurry from the mixing tank 81 to the grouting pipe 9, and then transport it to the sealing mechanism A to seal the gas extraction hole B. The grouting pump 83 can provide the required stable delivery pressure and flow rate for the negative carbon slurry, realize the quantitative delivery of the negative carbon slurry, and ensure that the negative carbon slurry and CO2 micron bubbles are fully mixed in the pipeline confluence section and smoothly injected into the sealing mechanism A to seal the gas extraction hole B.

[0068] The sealing mechanism A includes a sealing bag A1 and a rupture valve A2. The second end of the grouting pipe 9 is inserted into the gas extraction hole B. Two sealing bags A1 are included. The two sealing bags A1 are fitted onto the second end of the grouting pipe 9 at a predetermined distance, both communicating with the grouting pipe 9 and located within the gas extraction hole B. A grouting section is formed between the two sealing bags A1. The rupture valve A2 is installed on the grouting pipe 9 between the two sealing bags A1.

[0069] Grouting pipe 9 is used to mix CO2 negative carbon slurry with CO2 micron-sized bubbles to obtain sealing slurry, which is then transported to sealing bag A1. Sealing bag A1 is used to define the injection area of ​​the negative carbon slurry. During the injection of sealing slurry, the two sealing bags A1 expand under the injection pressure and tightly adhere to the borehole wall of gas extraction hole B, defining the sealing range and effectively preventing leakage of sealing slurry, ensuring that the sealing slurry is fully filled and solidified within the target sealing section. Burst valve A2 is used to automatically open when the pressure inside grouting pipe 9 reaches a set threshold, allowing the sealing slurry to instantly enter the sealing section.

[0070] The sealing injection device for gas extraction hole B provided in this embodiment of the application further includes a backwash pipe, a backwash valve, a three-way valve, and a waste discharge pipe (not shown in the figure). The first end of the backwash pipe is supplied with a cleaning medium (clean water or compressed air), and the second end is connected to the side wall of the CO2 gas injection pipe 4 between the mass flow controller 6 and the gas diffuser 7. The first end of the three-way valve is connected to the second end of the gas diffuser 7, the second end is connected to the grouting pipe 9, and the third end is connected to the first end of the waste discharge pipe.

[0071] In practice, the gas diffuser 7, with its micron-sized pores, is a key component for generating CO2 micron-sized bubbles and is also the most prone to clogging. During normal grouting, both cylinder valve 2 and pressure reducing valve 5 are open, allowing CO2 gas to flow freely in the CO2 gas injection pipe 4. At this time, the backwash valve is closed, cutting off the backwash pipe to prevent backflow of cleaning media or gas leakage. The three-way valve is opened to connect the gas diffuser 7 to the grouting pipe 9. CO2 micron-sized bubbles normally enter the grouting pipe 9 and mix with the negative carbon slurry. During breaks in grouting operations or after the completion of construction for the day, the gas diffuser 7 is backwashed. Specifically, cylinder valve 2 and pressure reducing valve 5 are closed, cutting off the main CO2 gas path and protecting the equipment on the gas source side. The backwash valve is opened, and the cleaning medium (clean water or compressed air) enters the CO2 gas injection pipe 4 through the backwash pipe and then enters the gas diffuser 7 for cleaning, thereby keeping the pores of the gas diffuser 7 unobstructed, extending its service life, and maintaining the stability of CO2 micron-sized bubble generation. The three-way valve opens to connect the gas diffuser 7 to the waste discharge pipe, directing the flushed waste (attached particles or initial sediment) to the waste discharge pipe instead of entering the grouting pipe 9. This embodiment of the application achieves effective cleaning and maintenance of the gas diffuser 7, requiring only the switching of a few valves to change the process, making operation simple. Direct backflushing effectively removes blockages with significant results. It adds few components, keeping costs under control. It significantly extends the service life of the gas diffuser 7, ensures stable generation of micron-sized bubbles, and improves the long-term operational stability of the entire device, thereby ensuring the quality and continuity of the entire sealing process.

[0072] The sealing injection device for gas extraction holes provided in this application embodiment further includes an adjustable elbow mechanism, an electric actuator, a control mechanism, and a slurry viscosity sensor (not shown in the figure). The adjustable elbow mechanism includes a hinged elbow and a ball joint. The hinged elbow includes a connecting pipe and a ball head. The first end of the connecting pipe is fixedly connected to the second end of the gas diffuser 7. For example, the first end of the first connecting pipe and the second end of the gas diffuser 7 can be fixedly connected by setting flanges at the first end of the first connecting pipe and the second end of the gas diffuser 7. The ball head is integrally fixed at the second end of the connecting pipe, and the inner cavities of the connecting pipe and the ball head are smooth flow channels. The inner cavity of the ball joint is a ball cavity adapted to the ball head, and a through hole is provided at the bottom, which is fixed to the outer wall of the grouting pipe 9. The ball head is nested in the ball joint. This adjustable elbow is usually made of high strength and corrosion resistance (such as stainless steel or engineering plastics) to ensure wear resistance and sealing performance.

[0073] A slurry viscosity sensor is installed in the slurry preparation mechanism 8 and electrically connected to the control mechanism. It measures the viscosity of the negative carbon slurry prepared by the slurry preparation mechanism 8 and transmits the viscosity value to the control mechanism. Specifically, the viscosity sensor can be a slurry viscosity sensor (such as a rotational viscometer or a vibration sensor), installed on the mixing tank 81 of the slurry preparation mechanism 8. Alternatively, the viscosity sensor can be a grouting pump torque sensor, integrated into the motor of the grouting pump 83 in the slurry preparation mechanism 8. The grouting pump torque sensor monitors the load on the grouting pump 83; higher viscosity results in increased torque. Another option is a pipeline pressure drop sensor, such as a pressure sensor, installed on the grouting pipe 9 before and after the junction of the negative carbon slurry and CO2 micron-sized bubbles. This sensor measures the pressure difference after the junction point; increased pressure drop indicates higher viscosity or increased turbulence.

[0074] The output end of the electric actuator is connected to the connecting pipe and electrically connected to the control mechanism. The control mechanism controls the working state of the electric actuator according to the viscosity value, so that the electric actuator drives the hinged elbow to rotate around the ball joint, thereby adjusting the obtuse angle between the grouting pipe 9 and the CO2 gas injection pipe 4 in real time. When the viscosity value is high, the control mechanism sends a command to reduce the obtuse angle (e.g., to 90°-110°) to enhance shear; when the viscosity value is low, the control mechanism sends a command to increase the obtuse angle (e.g., to 130°-150°) to reduce turbulence, thereby achieving adaptive matching for different slurry viscosity conditions.

[0075] The electric actuator includes a rotary servo motor and a coupling. The output shaft of the rotary servo motor is directly coupled to the connecting pipe via the coupling. The rotary servo motor is electrically connected to the control mechanism.

[0076] The sealing injection device for gas extraction holes provided in this application embodiment uses a slurry viscosity sensor to monitor the viscosity value of the negative carbon slurry prepared by the slurry preparation mechanism 8 in real time, and transmits this data to the control mechanism via an electrical signal. The control mechanism automatically calculates and generates instructions based on changes in viscosity (e.g., increased shear force for high viscosity, reduced turbulence for low viscosity), and then drives an electric actuator (e.g., a rotary servo motor). The electric actuator drives a hinged elbow to rotate around a ball joint, thereby adjusting the obtuse angle between the grouting pipe 9 and the CO2 gas injection pipe 4 in real time (e.g., the angle decreases to 90°–110° for high viscosity and increases to 130°–150° for low viscosity). This obtuse angle adjustment is achieved by the rotation of the ball head of the hinged elbow within the ball joint, ensuring that the smooth flow channels of the connecting pipe and the inner cavity of the ball head always maintain the smooth flow of CO2 micron bubbles and negative carbon slurry, ultimately optimizing the shearing effect of the negative carbon slurry on the CO2 micron bubbles, and promoting uniform mixing of the two within the grouting pipe 9 to form a more stable sealing slurry. By monitoring parameters in real time through a slurry viscosity sensor, the control mechanism processes the viscosity value and calculates the target angle. The control mechanism then sends a command to the electric actuator, which drives the hinged elbow to rotate to the new position. The entire closed-loop adjustment continues until the operating conditions are matched, achieving adaptive closed-loop control of the sealing slurry viscosity. By dynamically adjusting the confluence angle to adapt to different operating conditions (such as changes in the proportion of coal-based solid waste or fluctuations in ambient temperature), the dispersion uniformity and reaction efficiency of CO2 micron bubbles in the negative carbon slurry are significantly improved. This avoids the risk of reduced sealing strength or sealing failure caused by uneven mixing, while enhancing the process stability and reliability of the device. Especially under the complex conditions of deep mines, it can ensure the consistency and long-term durability of sealing quality and reduce maintenance requirements.

[0077] When the CO2 gas injection pipe 4 includes a first injection sub-pipe 41 and a second injection sub-pipe 42, an adjustable elbow mechanism is also provided at the second end of the first injection sub-pipe 41 and the first end of the second injection sub-pipe 42 to accommodate the rotation of the second injection sub-pipe 42.

[0078] When the device includes a three-way valve, the first end of the connecting pipe is connected to the second end of the three-way valve.

[0079] Furthermore, both the mass flow controller 6 and the slurry preparation mechanism 8 are electrically connected to the control mechanism. Specifically, the drive motors of the grouting pump 83 of both the mass flow controller 6 and the slurry preparation mechanism 8 are electrically connected to the control mechanism. By setting the mass flow controller 6 and the slurry preparation mechanism 8 within the same control mechanism, the mass ratio of CO2 gas to negative carbon slurry is kept within a preset range, achieving linkage control of the mixing ratio of CO2 gas and negative carbon slurry. Specifically, the control mechanism calculates the mass ratio of CO2 gas to negative carbon slurry in real time based on the opening degree of the mass flow controller 6 and the rotation speed of the grouting pump 83 of the slurry preparation mechanism 8. When the mass ratio deviates from the preset range, the control mechanism automatically adjusts the opening degree of the mass flow controller 6 and the rotation speed of the grouting pump 83 to stabilize the mass ratio of CO2 to negative carbon slurry within the preset range, which is 1% to 5%.

[0080] Of course, in practice, components such as pressure gauge 3 and pressure reducing valve 5 are also electrically connected to the control mechanism.

[0081] Furthermore, the sealing injection device for gas extraction holes provided in this application embodiment also includes a pressure sensor, a conductivity sensor, or an acoustic sensor. The pressure sensor and the conductivity sensor or acoustic sensor are disposed on the injection pipe 9 after the confluence section of the negative carbon slurry and CO2 micron-sized bubbles. The pressure sensor, conductivity sensor, or acoustic sensor is used to collect gas-containing characteristic signals reflecting the CO2 micron-sized bubble content in the sealing slurry, so as to determine the CO2 micron-sized bubble content in the sealing slurry. The pressure sensor, conductivity sensor, or acoustic sensor are all electrically connected to the control mechanism. The control mechanism is configured to adaptively adjust the mass ratio between the CO2 gas injection rate and the negative carbon slurry flow rate based on the real-time measured gas-containing characteristic signals, thereby maintaining the uniform dispersion of CO2 micron-sized bubbles in the sealing slurry under different operating conditions and changes in the performance of the sealing slurry, thereby improving the consistency and mechanical strength of the sealing body.

[0082] Another embodiment of the present invention provides a sealing injection method for gas extraction holes, comprising:

[0083] Step 1: Coal-based solid waste powder, sealing cement, and water are mixed in a preset ratio in the slurry preparation unit 8 to obtain negative carbon slurry. This negative carbon slurry is uniform and has good fluidity.

[0084] Specifically, coal-based solid waste powder, sealing cement, and water are added to the mixing tank 81 according to a preset ratio, and the agitator 82 is turned on for mechanical mixing until a uniform, fluid negative carbon slurry is formed. The mixing time is generally 5-10 minutes to ensure that the coal-based solid waste powder and sealing cement particles are fully mixed and to avoid stratification or sedimentation. The prepared negative carbon slurry is output to the grouting pipe 9 through the grouting pump 83.

[0085] Step 1 includes: mixing the nano-scale carbonization reaction catalyst with coal-based solid waste powder, sealing cement and water in a preset ratio in the slurry preparation device 8 to accelerate the subsequent reaction rate of CO2 and calcium minerals.

[0086] Further, step 1 includes: pre-dispersing the nano-scale carbonization reaction catalyst with water to obtain a dispersion, for example, by mechanical stirring or ultrasonic oscillation to form a stable dispersion, and then adding it together with coal-based solid waste powder, sealing cement and water into the slurry preparation mechanism 8 for stirring to obtain a negative carbon slurry.

[0087] The carbonation catalyst is selected from one or more combinations of nano-silica, nano-calcium carbonate, nano-metal oxides (such as Fe2O3, MgO), or carbon-based nanomaterials (such as carbon nanotubes, graphene). Preferably, the amount of carbonation catalyst added is 0.1% to 3% of the mass of the sealing cement. The carbonation catalyst can provide nucleation sites for carbonate formation and improve the microstructure of the negative carbon slurry, which can significantly shorten the carbonation and curing time and improve construction efficiency.

[0088] The steps preceding step 1 also include:

[0089] Step A1: Crush and grind the coal-based solid waste raw material to obtain coal-based solid waste pre-material with a particle size of less than 75μm.

[0090] Step A2: Activate the coal-based solid waste feedstock to obtain a coal-based solid waste mixture. The activation treatment includes at least one of chemical activation or biological activation.

[0091] In step A2, chemical activation includes leaching with a 15-5% dilute acid solution, which can be dilute sulfuric acid or an organic acid. This dilute acid leaching process removes some impurities from the coal-based solid waste feedstock and increases the dissolution rate of soluble calcium and magnesium ions.

[0092] Bioactivation involves treatment using microbial fermentation or bioleaching. This process can break down the passivation layer on the surface of coal-based solid waste feedstock, exposing more reactive sites.

[0093] Step A3: Separate the coal-based solid waste mixture into solid and liquid components, and dry the solid product to obtain coal-based solid waste powder.

[0094] Steps A1 to A3 are activation pretreatment steps for coal-based solid waste raw materials, which can improve the overall carbonization reaction efficiency of coal-based solid waste powder. Through a step-by-step pretreatment process (crushing and grinding → activation treatment → solid-liquid separation and drying), the raw coal-based solid waste raw materials are transformed into highly reactive coal-based solid waste powder. Particle size control (<75μm) increases the specific surface area of ​​the solid waste. Chemical activation (15%~5% dilute acid leaching) or biological activation (microbial fermentation / leaching) selectively dissolves active ions such as calcium and magnesium, and removes impurities (such as heavy metals and organic matter). The activated solid waste powder has a significantly increased calcium ion dissolution rate, allowing it to be more fully converted into carbonate minerals during the carbonization reaction. This not only strengthens the pore-sealing skeleton structure but also avoids the negative impact of impurities on the slurry's fluidity and solidification strength, ensuring the performance stability and reliability of the final pore-sealing slurry.

[0095] Step 2: Open CO2 cylinder 1. CO2 cylinder 1 outputs CO2 gas to CO2 gas injection pipe 4. The gas pressure and flow rate of CO2 gas are jointly regulated by cylinder valve 2, pressure gauge 3, pressure reducing valve 5 and mass flow controller 6 to form a stable CO2 gas flow to gas diffuser 7. Gas diffuser 7 decomposes CO2 gas into fine and uniform CO2 micron bubbles.

[0096] Step 3: The slurry preparation mechanism 8 delivers the prepared negative carbon slurry to the injection pipe 9. The gas diffuser 7 inputs CO2 micron bubbles into the injection pipe 9. The central axis of the injection pipe 9 and the central axis of the second end of the CO2 gas injection pipe 4 form an obtuse angle in the clockwise direction, so that the high-speed flowing negative carbon slurry will generate a shearing effect on the CO2 micron bubble airflow, further refining the CO2 micron bubbles. The negative carbon slurry and CO2 micron bubbles are uniformly mixed in the injection pipe 9 to obtain a sealing slurry. The two phases are fully mixed, which significantly improves the dispersion and reaction contact area of ​​CO2 gas in the negative carbon slurry, forming a stable CO2 gas-negative carbon slurry composite system.

[0097] Step 4: The sealing grout is introduced into the sealing mechanism A through the grouting pipe 9. The sealing mechanism A is set in the gas extraction hole B. After the sealing grout is introduced into the sealing mechanism A, the gas extraction hole B is sealed.

[0098] Specifically, the two sealing bags A1 expand and tightly adhere to the borehole wall of the gas extraction borehole B during the injection of sealing grout. When the pressure inside the grouting pipe 9 reaches the set value, the rupture valve A2 automatically opens, and the sealing grout instantly enters the sealing section, thus completing the filling under the confining effect of the sealing bags A1.

[0099] During the solidification process of the sealing slurry inside the gas extraction hole B, the dispersed CO2 micron-sized bubbles in the sealing slurry are gradually released during the solidification process, and react with the calcium minerals in the sealing cement and coal-based solid waste powder to generate stable crystals such as calcium carbonate, thereby achieving internal carbonization curing of the sealing body, significantly improving its strength and density, and thus forming a stable and durable sealing structure.

[0100] The sealing injection method for gas extraction boreholes provided in this invention, through constructing a complete process of "negative carbon slurry preparation → CO2 micron-sized bubble generation → shear mixing → grouting and sealing," achieves active carbonization curing inside the gas extraction borehole B for the first time. This method decomposes CO2 gas into micron-sized bubbles via a diffuser, and utilizes the obtuse angle design (110°~135°) between the grouting pipe 9 and the gas injection pipe to cause the high-speed flowing negative carbon slurry to shear the bubble flow, forcibly refining the bubbles and promoting uniform mixing. This design overcomes the limitations of traditional external CO2 curing in a closed borehole environment, allowing CO2 to be released from within during the slurry solidification process, reacting with calcium minerals in coal-based solid waste and cement to generate calcium carbonate crystals, significantly improving the compressive strength and density of the sealing body. Simultaneously, the incorporation of coal-based solid waste achieves solid waste resource utilization, and combined with CO2 sealing, achieves the dual environmental benefits of "treating waste with waste," fundamentally solving the technical problems of easy cracking of cement-based materials and sealing failure in deep, high-stress mines.

[0101] This embodiment of the application injects CO2 gas, diffused into micron-sized CO2 bubbles, into a negative carbon slurry composed of coal-based solid waste powder and sealing cement, into gas extraction hole B. Within gas extraction hole B, CO2 fully reacts with the coal-based solid waste powder and sealing cement, achieving internal carbonization curing of the sealing material and CO2 mineralization and sequestration. The method of this embodiment improves the strength and density of the sealing body, enhances the long-term stability of the sealing and the gas extraction effect, and simultaneously achieves the synergistic benefits of resource utilization of coal-based solid waste and CO2 sequestration. It possesses comprehensive advantages such as simple process, safety and reliability, and environmental friendliness.

[0102] The various embodiments in this specification are described in a progressive manner. For the same or similar parts between the various embodiments, please refer to each other. Each embodiment focuses on describing the differences from other embodiments.

[0103] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit this application. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of this application.

Claims

1. A sealing injection device for gas extraction wells, characterized in that, Includes CO2 cylinders, cylinder valves, pressure gauges, CO2 gas injection pipes, pressure reducing valves, mass flow controllers, gas diffusers, slurry preparation mechanisms, grouting pipes, and sealing mechanisms; The gas diffuser includes a cylinder and a diffuser plate, and the diffuser plate has a plurality of through holes evenly distributed on it. The first end of the CO2 gas injection pipe is connected to the output port of the CO2 gas cylinder, and the second end is fixed to the first end of the gas diffuser where the diffuser plate is located. The CO2 gas injection pipe is provided with the gas cylinder valve, the pressure gauge, the pressure reducing valve and the mass flow controller in sequence along the direction from the CO2 gas cylinder to the gas diffuser; The first end of the grouting pipe is connected to the output port of the grout preparation mechanism, and the second end is connected to the sealing mechanism. The second end of the gas diffuser is connected to the outer wall of the grouting pipe, and the central axis of the grouting pipe is at an obtuse angle to the central axis of the second end of the CO2 gas injection pipe in a clockwise direction, so as to deliver CO2 micron bubbles to the grouting pipe; The slurry preparation mechanism is used to mix coal-based solid waste powder, sealing cement and water in a preset ratio to obtain negative carbon slurry, which is then transported to the grouting pipe. The negative carbon slurry is then mixed with CO2 micron bubbles to obtain sealing slurry, which is then transported to the sealing mechanism. The sealing mechanism is installed inside the gas extraction hole and is used to seal the gas extraction hole after the sealing slurry is introduced.

2. The sealing injection device for gas extraction holes according to claim 1, characterized in that, The slurry preparation mechanism includes a mixing tank, a stirrer, and a slurry pump; The stirrer is inserted into the mixing tank; The grouting pump is mounted on the mixing tank, with its inlet located inside the mixing tank and its outlet connected to the first end of the grouting pipe.

3. The sealing injection device for gas extraction holes according to claim 1, characterized in that, The sealing mechanism includes a sealing bag and a burst valve; The second end of the grouting pipe is inserted into the gas extraction hole; The sealing bag includes two bags, which are fitted at a predetermined distance to the second end of the grouting pipe and are both connected to the grouting pipe and located inside the gas extraction hole. The burst valve is located on the grouting pipe between the two sealing bags.

4. The sealing injection device for gas extraction holes according to claim 1, characterized in that, It also includes backwash pipes, backwash valves, three-way valves, and waste discharge pipes; The first end of the backwash pipe is fed with the cleaning medium, and the second end is connected to the side wall of the CO2 gas injection pipe between the mass flow controller and the gas diffuser. The first end of the three-way valve is connected to the second end of the gas diffuser, the second end is connected to the grouting pipe, and the third end is connected to the first end of the waste discharge pipe.

5. The sealing injection device for gas extraction holes according to claim 1, characterized in that, It also includes an adjustable elbow mechanism, an electric actuator, a control mechanism, and a slurry viscosity sensor; The adjustable elbow mechanism includes a hinged elbow and a ball joint. The hinged elbow includes a connecting pipe and a ball joint; The first end of the connecting pipe is fixedly connected to the second end of the gas diffuser; The ball head is fixed at the second end of the connecting pipe, and the inner cavity of the connecting pipe and the ball head is a smooth flow channel; The inner cavity of the ball joint is a ball cavity adapted to the ball head, and a through hole is provided at the bottom, which is fixed to the outer wall of the grouting pipe; The ball head is nested within the ball socket joint; The slurry viscosity sensor is disposed in the slurry preparation mechanism and electrically connected to the control mechanism, and is used to measure the viscosity value of the negative carbon slurry prepared by the slurry preparation mechanism and transmit the viscosity value to the control mechanism; The output end of the electric actuator is connected to the connecting pipe and electrically connected to the control mechanism. The control mechanism controls the working state of the electric actuator according to the viscosity value so that the electric actuator drives the hinged elbow to rotate around the ball joint, thereby adjusting the obtuse angle between the grouting pipe and the CO2 gas injection pipe in real time.

6. The sealing injection device for gas extraction holes according to claim 5, characterized in that, Both the mass flow controller and the slurry preparation mechanism are electrically connected to the control mechanism.

7. A sealing injection method for gas extraction wells, characterized in that, The sealing injection device for gas extraction holes according to any one of claims 1 to 6 includes: Step 1: Mix coal-based solid waste powder, sealing cement, and water in a slurry preparation device according to a preset ratio to obtain negative carbon slurry; Step 2: Open the CO2 cylinder. The CO2 cylinder outputs CO2 gas to the CO2 gas injection pipe. The gas pressure and flow rate of the CO2 gas are jointly regulated by the cylinder valve, pressure gauge, pressure reducing valve and mass flow controller to form a stable CO2 gas flow to the gas diffuser. The gas diffuser decomposes the CO2 gas into CO2 micron bubbles. Step 3: The slurry preparation mechanism delivers the prepared negative carbon slurry to the grouting pipe, and the gas diffuser inputs the CO2 microbubbles into the grouting pipe. The central axis of the grouting pipe and the central axis of the second end of the CO2 gas injection pipe form an obtuse angle in the clockwise direction, so that the high-speed flowing negative carbon slurry generates a shearing effect on the airflow of the CO2 microbubbles. The negative carbon slurry and the CO2 microbubbles are uniformly mixed in the grouting pipe to obtain a sealing slurry. Step 4: The sealing grout is fed into the sealing mechanism through the grouting pipe. The sealing mechanism is set inside the gas extraction hole. After the sealing grout is fed into the sealing mechanism, the gas extraction hole is sealed.

8. The sealing injection method for gas extraction holes according to claim 7, characterized in that, Step 1 includes: mixing the nano-scale carbonization reaction catalyst with coal-based solid waste powder, sealing cement and water in the slurry preparation device according to a preset ratio.

9. The sealing injection method for gas extraction holes according to claim 7, characterized in that, The steps preceding step 1 also include: Step A1: Crush and grind the coal-based solid waste raw material to obtain coal-based solid waste pre-material with a particle size of less than 75μm; Step A2: Activate the coal-based solid waste feedstock to obtain a coal-based solid waste mixture, wherein the activation treatment includes at least one of chemical activation or biological activation; Step A3: Separate the coal-based solid waste mixture into solid and liquid components, and dry the solid product to obtain coal-based solid waste powder.

10. The sealing injection method for gas extraction holes according to claim 9, characterized in that, In step A2, the chemical activation includes leaching treatment with a dilute acid solution with a concentration of 15-5%; The bioactivation includes treatment using microbial fermentation or bioleaching methods.

Images