A goaf nitrogen injection pipeline and monitoring beam pipe burying method

Abstract

The application discloses a goaf nitrogen injection pipeline and monitoring beam pipe burying method, which comprises the following steps: obtaining the width of a heat dissipation zone and the width of an oxidation zone of a goaf; calculating the number of nitrogen injection pipelines and the number of monitoring beam pipes; determining the pipeline burying step distance according to the width of the oxidation zone; burying the nitrogen injection pipelines and the monitoring beam pipes, wherein the outlet end of the nitrogen injection pipeline is located in the oxidation zone, and the air inlet of the monitoring beam pipe is located in the oxidation zone; with the movement of a coal mining face, the heat dissipation zone and the oxidation zone move accordingly; the nitrogen injection device is disconnected from the nitrogen injection pipeline that moves out of the oxidation zone, and is connected to the next section of the nitrogen injection pipeline that enters the oxidation zone; the air extraction device is disconnected from the monitoring beam pipe that moves out of the oxidation zone, and is connected to the next section of the monitoring beam pipe that enters the oxidation zone. The goaf nitrogen injection pipeline and monitoring beam pipe burying method can realize reasonable pipeline arrangement, accurate nitrogen injection and effective monitoring, improve the fire prevention and extinguishing efficiency, and reduce the fire prevention and extinguishing cost.

Description

Technical Field

[0001] This invention belongs to the field of coal mining technology, and in particular relates to a method for burying nitrogen injection pipelines and monitoring bundles in goaf areas. Background Technology

[0002] Spontaneous combustion of coal seams in goaf areas is one of the main causes of mine fires, seriously threatening safe production and the lives of personnel. Currently, the common solution in coal mines is to inject nitrogen into the goaf for inerting, combined with a monitoring tube system for fire prevention and control. Specifically, this nitrogen injection pipeline is used to inject nitrogen into the goaf to relatively reduce the oxygen concentration, thereby suppressing spontaneous combustion of the coal seam. The monitoring tubes collect gas samples from the goaf to analyze changes in the concentration of oxygen and other gases, thus enabling early warning of fires.

[0003] However, in practical applications, the number of nitrogen injection pipelines and monitoring tubes buried often relies on the engineering experience of relevant personnel or simple estimations, lacking a unified and scientific calculation method. This leads to the inability to accurately locate the outlet of the nitrogen injection pipeline, resulting in several abnormal situations. The first situation is that nitrogen injection begins before the nitrogen injection pipeline enters the oxidation zone, causing the injected nitrogen to dissipate in the heat dissipation zone. In this case, the nitrogen cannot inerte the oxidized coal in the oxidation zone, resulting in an unsatisfactory nitrogen injection effect. The second situation is that after the outlet of the nitrogen injection pipeline has been introduced into the asphyxiation zone, the injected nitrogen is not switched in a step-by-step manner in time. This results in the injected nitrogen being wasted in the asphyxiation zone and not being used to inerte the coal in the oxidation zone.

[0004] In summary, the existing nitrogen injection methods for goaf areas suffer from problems such as uneven nitrogen injection pipeline coverage, unsatisfactory nitrogen inerting effect, and resource waste due to the large number of pipelines laid arbitrarily. Therefore, it is difficult to achieve precise fire prevention and control. Summary of the Invention

[0005] To address the aforementioned issues, this invention provides a method for burying nitrogen injection pipelines and monitoring bundles in goaf areas. This method enables rational pipeline layout, precise nitrogen injection, and effective monitoring, thereby improving the efficiency of fire prevention and extinguishing while reducing the cost of fire prevention and extinguishing.

[0006] This invention provides a method for burying nitrogen injection pipelines and monitoring bundles in goaf areas, comprising:

[0007] Obtain the width of the heat dissipation zone and the width of the oxidation zone in the goaf;

[0008] The number of nitrogen injection lines and the number of monitoring tubes are calculated based on the width of the heat dissipation zone and the width of the oxidation zone.

[0009] The pipeline laying distance is determined based on the width of the oxide zone, and the pipeline laying distance is not greater than the width of the oxide zone;

[0010] Based on the number of nitrogen injection pipelines, the number of monitoring bundles, and the pipeline burial spacing, the nitrogen injection pipelines and monitoring bundles are buried. The outlet end of the nitrogen injection pipeline is located within the oxidation zone, and the inlet of the monitoring bundle is located within the oxidation zone.

[0011] As the coal mining face moves, the heat dissipation zone and the oxidation zone move accordingly. At the same time, the nitrogen injection device is disconnected from the nitrogen injection pipeline that moves out of the oxidation zone, and connected to the next section of the nitrogen injection pipeline that enters the oxidation zone. This process is repeated to ensure that the oxidation zone can be injected with nitrogen at any time.

[0012] While disconnecting the gas extraction device from the monitoring tube that has been removed from the oxidation zone, connect it to the next monitoring tube that has entered the oxidation zone, and so on, to ensure that the gas concentration in the oxidation zone can be monitored at any time.

[0013] Preferably, in the above-mentioned method for burying nitrogen injection pipelines and monitoring bundles in the goaf, the step of calculating the number of nitrogen injection pipelines and the number of monitoring bundles based on the width of the heat dissipation zone and the width of the oxidation zone includes:

[0014] Divide the width of the heat dissipation strip by the width of the oxide strip, round the result up, and add 1 to obtain the number of nitrogen injection lines and the number of monitoring tubes.

[0015] Preferably, in the above-mentioned method for burying nitrogen injection pipelines and monitoring bundles in the goaf, the step of obtaining the width of the heat dissipation zone and the width of the oxidation zone in the goaf is as follows:

[0016] Based on a comprehensive assessment of actual on-site measurement data and numerical simulation results, the width of the heat dissipation zone and the width of the oxidation zone in the goaf are determined.

[0017] Preferably, in the above-mentioned method for burying nitrogen injection pipelines and monitoring bundles in the goaf, the width of the heat dissipation zone and the width of the oxidation zone in the goaf are determined by comprehensively judging based on actual on-site measurement data and numerical simulation results:

[0018] Based on the actual on-site measurement data and the numerical simulation results, the oxygen concentration distribution is determined. The width of the area behind the working face with an oxygen concentration higher than 18% is taken as the width of the heat dissipation zone, and the width of the area with an oxygen concentration between 10% and 18% is taken as the width of the oxidation zone.

[0019] Preferably, in the above-mentioned method for burying nitrogen injection pipelines and monitoring bundles in the goaf, the pipeline burial step distance is 0.8 to 1.0 times the width of the oxidation zone.

[0020] Preferably, in the above-mentioned method for burying nitrogen injection pipelines and monitoring bundles in goaf areas, the pipeline burial step distance is an integer multiple of a single pipeline section.

[0021] Preferably, in the above-mentioned method for burying nitrogen injection pipelines and monitoring bundles in the goaf, the nitrogen injection device is a membrane separation nitrogen generator or a pressure swing adsorption nitrogen generator.

[0022] Preferably, in the above-mentioned method for burying nitrogen injection pipelines and monitoring bundles in the goaf, the gas extraction device is an intrinsically safe gas sampler for mining.

[0023] Preferably, in the above-mentioned method for burying nitrogen injection pipelines and monitoring bundles in the goaf, the nitrogen injection pipeline is a steel pipe with a diameter of 108 mm.

[0024] Preferably, in the above-mentioned method for burying nitrogen injection pipelines and monitoring bundles in goaf areas, redundant monitoring bundles are also provided, with a redundancy of 1 to 2 lines.

[0025] As described above, the method for burying nitrogen injection pipelines and monitoring bundles in a goaf provided by the present invention includes: first, obtaining the width of the heat dissipation zone and the width of the oxidation zone in the goaf; then, calculating the number of nitrogen injection pipelines and the number of monitoring bundles based on the width of the heat dissipation zone and the width of the oxidation zone; next, determining the pipeline burial step distance based on the width of the oxidation zone, wherein the pipeline burial step distance is not greater than the width of the oxidation zone; and finally, burying the nitrogen injection pipelines and monitoring bundles according to the number of nitrogen injection pipelines, the number of monitoring bundles, and the pipeline burial step distance. The outlet end of the nitrogen injection pipeline is located within the oxidation zone, and the inlet of the monitoring bundle is also located within the oxidation zone. Then, as the coal face moves, the heat dissipation zone and the oxidation zone move accordingly. Simultaneously, the nitrogen injection device is disconnected from the nitrogen injection pipeline that has moved out of the oxidation zone, and connected to the next section of the nitrogen injection pipeline entering the oxidation zone. This process is repeated to ensure that nitrogen can be injected into the oxidation zone at any given time. Similarly, the gas extraction device is disconnected from the monitoring tube that has moved out of the oxidation zone, and connected to the next section of the monitoring tube entering the oxidation zone. This process is repeated to ensure that the gas concentration in the oxidation zone can be monitored at any given time. This method enables reasonable pipe layout, precise nitrogen injection, and effective monitoring, improving the efficiency of fire prevention and extinguishing while reducing the cost of fire prevention and extinguishing. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of an embodiment of a method for burying nitrogen injection pipelines and monitoring bundles in a goaf area provided by the present invention;

[0028] Figure 2 A schematic diagram of a two-channel alternating nitrogen injection method;

[0029] Figure 3 This is a schematic diagram of a three-way alternating nitrogen injection method;

[0030] Figure 4 A schematic diagram for monitoring the management board of the bundle tube. Detailed Implementation

[0031] The core of this invention is to provide a method for burying nitrogen injection pipelines and monitoring bundles in goaf areas, which can achieve reasonable pipeline layout, accurate nitrogen injection and effective monitoring, improve the efficiency of fire prevention and firefighting, and reduce the cost of fire prevention and firefighting.

[0032] 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 embodiments of the present invention, and not all embodiments. 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.

[0033] An example of the implementation of the nitrogen injection pipeline and monitoring bundle installation method provided by this invention in a goaf area Figure 1 As shown, Figure 1 This is a schematic diagram of an embodiment of a method for burying nitrogen injection pipelines and monitoring bundles in a goaf area provided by the present invention. The method may include the following steps:

[0034] S1: Obtain the width of the heat dissipation zone and the width of the oxidation zone in the goaf;

[0035] Specifically, the width of the heat dissipation zone and the width of the oxidation zone in the goaf can be determined by comprehensively considering actual on-site measurement data and numerical simulation results. This determination process can follow an iterative workflow of "simulation first, actual measurement calibration": First, a model is established. Based on the geological and mining conditions of the working face, a CFD numerical model reflecting the actual situation is constructed. Then, simulation calculations are performed, and the model is run to calculate the two-dimensional / three-dimensional distribution of the flow field, oxygen concentration field, and temperature field in the goaf. Based on this, the "three zones" are initially delineated. Finally, actual measurement calibration is performed by arranging a series of measuring points in the goaf to actually measure the oxygen concentration (…). ), gas concentration ( Parameters such as temperature are used to compare and contrast measured data (especially indicative parameters, such as the oxygen concentration dropping to 8%) with simulation results. A comprehensive judgment is then made. If the simulation results are highly consistent with the measured results, the simulation results are directly adopted. If there are deviations, the rationality of the model parameters (such as porosity and air leakage intensity) is analyzed by inversion, and the model is corrected until it can truly reflect the measured data. Finally, based on the physical field distribution shown by the calibrated numerical model, the width of each band is accurately defined. The uncertainty is explained as follows: the final width value will indicate its possible error range, which is evaluated based on the density of measuring points and the residual error of model calibration.

[0036] S2: Calculate the number of nitrogen injection lines and the number of monitoring tubes based on the width of the heat dissipation zone and the width of the oxidation zone;

[0037] Specifically, this step may include: dividing the width of the heat dissipation band by the width of the oxide band, rounding the result up, and then adding 1 to obtain the number of nitrogen injection lines and the number of monitoring tubes. In one example, according to the formula... Calculate the basic quantity of such nitrogen injection pipelines and monitoring bundles, where 'a' represents the width of the heat dissipation zone in the goaf, and 'b' represents the width of the oxidation zone in the goaf, both in meters (m). The heat dissipation zone is located behind the working face in the interval 0 to 'a', and the oxidation zone immediately follows the heat dissipation zone, located a to (a+b) meters behind the working face. The rounding up indicates that the calculation method for the number of pipelines is the same for both types. The governance concept is to monitor and inertate the coal in the oxidation zone of the working face, ensuring that there are no monitoring blind spots or inerting dead zones within the oxidation zone. Based on this calculation method, nitrogen injection pipelines and monitoring bundles should be laid in stages along the working face advancement direction, with the spacing between each pipeline controlled within b meters to ensure coverage of the entire dynamically evolving area of ​​the oxidation zone. The pipeline start / stop and nitrogen injection parameters are adjusted in real time based on the coal mining progress and the migration speed of the "three zones" (oxidation zone, gas, and seismic zone) to improve inerting efficiency. Through the coordinated optimization of deployment density and nitrogen injection intensity, full-time, full-coverage control of the oxidation zone is achieved, effectively curbing the risk of spontaneous combustion of coal. Simultaneously, based on the difference in the width of the "three zones" on the intake and return air sides, the number of pipelines on both sides can be calculated and differentiated separately.

[0038] S3: Determine the pipeline laying distance based on the width of the oxide zone; the pipeline laying distance shall not exceed the width of the oxide zone.

[0039] It should be noted that the pipeline installation spacing must be designed to ensure no gaps in nitrogen injection, guaranteeing continuous nitrogen injection into the oxidation zone. Specifically, this pipeline installation spacing is less than or equal to the width of the oxidation zone to account for errors during switching. For example, if the oxidation zone width is 35 meters, and the pipeline installation spacing is set to 32 meters, then the stepping pipeline has a 3-meter safety switching distance within the oxidation zone. This means that when the pipeline about to enter the asphyxiation zone is 3 meters away from entering the asphyxiation zone, the second stepping pipeline has already entered the oxidation zone.

[0040] S4: Based on the number of nitrogen injection pipelines, the number of monitoring tubes, and the pipeline burial spacing, the nitrogen injection pipelines and monitoring tubes are buried. The outlet end of the nitrogen injection pipeline is located within the oxidation zone, and the inlet of the monitoring tube is located within the oxidation zone.

[0041] S5: As the coal mining face moves, the heat dissipation zone and oxidation zone also move. At the same time, the nitrogen injection device is disconnected from the nitrogen injection pipeline that moves out of the oxidation zone, and connected to the next section of the nitrogen injection pipeline that enters the oxidation zone. This process is repeated to ensure that nitrogen can be injected into the oxidation zone at any time.

[0042] Specifically, the nitrogen injection device can inject nitrogen into the nitrogen injection pipeline it is connected to, and then release the nitrogen from the outlet of that pipeline, thus continuously inerting the oxidation zone and avoiding the risk of fire. In this step, since the pre-buried nitrogen injection pipeline is stationary, it only moves forward as the coal mining face moves, causing the heat dissipation zone and oxidation zone to move forward as well. As a result, the nitrogen injection pipeline, which was originally located in the oxidation zone, gradually moves out of the oxidation zone because the two are constantly in relative motion. Just before the outlet of the nitrogen injection pipeline moves out of the oxidation zone, the nitrogen injection device can be disconnected from it and immediately connected to the next section of the nitrogen injection pipeline whose outlet will enter the oxidation zone, so that nitrogen can be injected into the oxidation zone from the next section of the nitrogen injection pipeline, thereby achieving uninterrupted nitrogen injection and avoiding the risk of fire due to high oxygen concentration.

[0043] Specifically, the two-way alternating nitrogen injection method is as follows: Figure 2 As shown, Figure 2This diagram illustrates a two-way alternating nitrogen injection method. First, as shown on the left, the coal face continuously moves to the right, causing the resulting asphyxiation zone, oxidation zone, and heat dissipation zone to also shift to the right. At this point, the main nitrogen injection pipeline is connected to nitrogen injection pipe #1 to inject nitrogen into the oxidation zone. Nitrogen injection pipe #2 is pre-buried at the roof cutting line. Then, as shown on the right, the original nitrogen injection pipe #1 has entered the asphyxiation zone, so nitrogen injection operation on pipe #1 is stopped, and nitrogen injection operation on pipe #2 is activated. Pipe #1 is then disconnected at the roof cutting line, and the next cycle of pre-buried nitrogen injection begins. In other words, nitrogen injection pipe #1 is pre-buried again, and subsequently, nitrogen injection operation on pipe #2 is stopped, and nitrogen injection is switched to the newly pre-buried pipe #1. This cycle of pre-buried and switching is repeated, enabling continuous nitrogen injection into the oxidation zone.

[0044] In addition, the three-way alternating nitrogen injection method is as follows: Figure 3 As shown, Figure 3 This diagram illustrates a three-way alternating nitrogen injection system. First, as shown in the upper left corner, when the three nitrogen injection pipes are pre-installed, nitrogen injection pipe #1 enters the oxidation zone. The distance between nitrogen injection pipe #2 and #1 is equal to the width of the oxidation zone, and the distance between nitrogen injection pipe #3 and #2 is also equal to the width of the oxidation zone. At this point, the main nitrogen injection line is connected to nitrogen injection pipe #1, which injects nitrogen gas into the oxidation zone. Then, as shown in the upper right corner, when nitrogen injection pipe #1 enters the suffocation zone, nitrogen injection is stopped. At the top cut line, nitrogen injection pipe #1 is disconnected, and nitrogen injection pipe #2, which has already entered the oxidation zone, is activated. The distance between nitrogen injection pipe #3 and nitrogen injection pipe #2 is the width of the oxidation zone. Then, as shown in the lower left figure, when nitrogen injection pipe #2 enters the suffocation zone, stop nitrogen injection pipe #2 and disconnect nitrogen injection pipe #2 at the top cut line. Start nitrogen injection pipe #3 and use nitrogen injection pipe #3 to inject nitrogen into the oxidation zone. It can be seen that this is a step-by-step cycle. Finally, as shown in the lower right figure, when nitrogen injection pipe #3 enters the suffocation zone, stop nitrogen injection pipe #3 and disconnect nitrogen injection pipe #3 at the top cut line. Start nitrogen injection pipe #1 to ensure that one of the three nitrogen injection pipes is always in the oxidation zone.

[0045] It should also be noted that this nitrogen injection device can be a membrane separation nitrogen generator or a pressure swing adsorption (PSA) nitrogen generator. Specifically, the YJ-FT-1500 PSA nitrogen generator or the DM-600 / 10(L) type mobile, interconnected membrane separation nitrogen generator for mining can be selected. A membrane separation nitrogen generator is a device that uses a high-molecular hollow fiber membrane to physically separate oxygen and nitrogen in compressed air to produce nitrogen. Its core principle is that different gas molecules have different permeation rates in the membrane material. "Fast gases" such as oxygen and water vapor preferentially permeate through the membrane wall and are discharged, while nitrogen, as a "slow gas," is enriched and collected, thus achieving the separation purpose. It has the advantages of simple structure, small size, fast start-up, and stable operation. A pressure swing adsorption (PSA) nitrogen generator is a field nitrogen generator that uses carbon molecular sieves (CMS) as adsorbent and achieves oxygen and nitrogen separation in air through periodic pressure adsorption and depressurization desorption. It has advantages such as high nitrogen purity, low energy consumption, fast start-up, and high degree of automation. Of course, other types of nitrogen injection devices can be selected according to actual needs; there are no restrictions here.

[0046] S6: While disconnecting the gas extraction device from the monitoring tube that has been removed from the oxidation zone, connect it to the next monitoring tube that has entered the oxidation zone, and so on, to ensure that the gas concentration in the oxidation zone can be monitored at any time.

[0047] Specifically, this gas extraction device can preferably be an intrinsically safe gas sampler for mining, which can be used to collect gas samples in intrinsically safe environments. (etc.) for ground chromatography analysis. As in the steps described above, disconnecting from a monitoring tube that is about to be removed from the oxidation zone prevents further gas extraction, while simultaneously connecting to the next monitoring tube entering the oxidation zone allows for immediate gas extraction from this next monitoring tube. This ensures uninterrupted monitoring of gas concentration within the oxidation zone and guarantees that the sampled gas meets the requirements.

[0048] In summary, the location of the air intake of the monitoring tubes was not clearly recorded during their deployment. As the working face was mined, the burial depth of the air intake could not be accurately determined (it was impossible to accurately determine whether the air intake was in the oxidation zone or the asphyxiation zone). This resulted in the gas sampling data from the monitoring tubes failing to accurately reflect the gas situation in the goaf, leading to monitoring blind spots. Therefore, establishing an accurate calculation model for the number of nitrogen injection pipelines and monitoring tubes is crucial. This method comprehensively considers factors such as the working face advance speed, the distribution pattern of the three zones in the goaf, the width of the oxidation zone, and the gas migration path. Through theoretical calculations, it determines the effective coverage spacing and number of nitrogen injection pipelines, ensuring that the outlet end is always located within the oxidation zone. Simultaneously, based on the positioning requirements of the monitoring tubes and the gas concentration gradient changes along the depth direction of the goaf, it sets a reasonable tube layout density and sampling frequency, achieving dynamic and accurate monitoring of key areas and improving the reliability and economy of the fire prevention and extinguishing system.

[0049] As described above, in the embodiments of the method for burying nitrogen injection pipelines and monitoring bundles in goaf areas provided by the present invention, the following steps are involved: first, obtaining the width of the heat dissipation zone and the width of the oxidation zone in the goaf; then, calculating the number of nitrogen injection pipelines and the number of monitoring bundles based on the width of the heat dissipation zone and the oxidation zone; next, determining the pipeline burial step distance based on the width of the oxidation zone, with the pipeline burial step distance not exceeding the width of the oxidation zone; and then, burying the nitrogen injection pipelines and monitoring bundles according to the number of nitrogen injection pipelines, the number of monitoring bundles, and the pipeline burial step distance. The outlet end of the nitrogen injection pipeline is located within the oxidation zone, and the inlet of the monitoring bundle is also located within the oxidation zone. As the coal face moves, the heat dissipation zone and oxidation zone also move. Simultaneously, the nitrogen injection device is disconnected from the nitrogen injection pipeline exiting the oxidation zone, and connected to the next section of the nitrogen injection pipeline entering the oxidation zone. This process is repeated to ensure nitrogen injection into the oxidation zone at all times. Similarly, the gas extraction device is disconnected from the monitoring tube exiting the oxidation zone, and connected to the next section of the monitoring tube entering the oxidation zone. This process is repeated to ensure gas concentration monitoring within the oxidation zone at all times. This method enables rational pipe layout, precise nitrogen injection, and effective monitoring, improving fire prevention and extinguishing efficiency while reducing fire prevention and extinguishing costs.

[0050] In a specific embodiment of the above-mentioned method for burying nitrogen injection pipelines and monitoring bundles in goaf areas, based on a comprehensive determination of actual on-site measurement data and numerical simulation results, the specific widths of the heat dissipation zone and oxidation zone in the goaf area can be:

[0051] Based on actual on-site measurement data and numerical simulation results, the oxygen concentration distribution is determined. The width of the area behind the working face with an oxygen concentration higher than 18% is defined as the heat dissipation zone width, where the temperature is close to ambient temperature. The width of the area with an oxygen concentration between 10% and 18% is defined as the oxidation zone width. This oxidation zone is characterized by coal-oxygen complex reactions and is a high-risk area for spontaneous combustion. Of course, this demarcation method can be adjusted according to actual needs; there are no restrictions here.

[0052] Furthermore, beyond this lies the asphyxiation zone, where the oxygen concentration is below 10%, exhibiting characteristics that preclude the formation of self-sustaining combustion conditions. It should also be noted that because the leakage intensity differs between the intake and return air sides of the coal face, the range of the "three zones" on both sides needs to be calculated separately, resulting in irregular shapes for these zones.

[0053] In another specific embodiment of the above-mentioned method for burying nitrogen injection pipelines and monitoring bundles in the goaf, the pipeline burial spacing can preferably be 0.8 to 1.0 times the width of the oxide zone. Furthermore, the pipeline burial spacing can preferably be an integer multiple of a single pipeline section. Specifically, this spacing is set to ensure that the pipeline continuously and effectively covers the oxide zone area during its advancement, avoiding insufficient inerting or monitoring blind spots due to excessive spacing. Based on actual site conditions, the burial spacing should match the daily advance speed of the working face, typically taking 0.8 to 1.0 times the width of the oxide zone, and ensuring that at least one pipeline is within the effective range of each spacing. By rationally setting the spacing, pipeline waste can be reduced, and precise control can be maintained during the dynamic evolution of the oxide zone in the goaf, improving system response capabilities and operational economy. Simultaneously, the burial spacing needs to consider both the pipeline material length specifications and on-site construction efficiency, prioritizing integer multiples of the standard pipe length to reduce the number of joints, thereby further improving the system's sealing and reliability.

[0054] In another specific embodiment of the above-mentioned method for burying nitrogen injection pipelines and monitoring bundles in the goaf, the nitrogen injection pipeline can preferably be a steel pipe with a diameter of 108mm. When buried in the goaf of the working face, this type of steel pipe will not experience significant deformation or blockage due to coal seam compression, thus its structural strength meets the working conditions. Of course, other types of rigid material pipes can also be selected according to actual needs; this is not a limitation.

[0055] In a preferred embodiment of the above-mentioned method for burying nitrogen injection pipelines and monitoring bundles in goaf areas, redundant monitoring bundles can be added based on any of the above embodiments, with a redundancy of 1 to 2 channels. The bundle material is generally made of rigid plastic. The diameter of the bundles currently used in coal mines is 6-8mm. The requirement of 1 to 2 additional channels is due to the fact that the air intake of the bundle is easily blocked by broken coal in the goaf, affecting the gas data acquisition. The original single-channel bundle is combined into a multi-core bundle to prevent the bundle from being blocked by coal or fine coal dust in the goaf. 1 to 2 additional channels means that 2 or more channels are buried as a whole. In other words, because the monitoring bundle tube is made of a relatively soft material and is easily affected by mining activities, it is at risk of being squeezed and broken or having its signal interrupted. Therefore, based on the calculated value of n, one or two monitoring bundle tubes are added to prevent monitoring failure due to mining damage. This ensures that gas data in the goaf can be continuously acquired even under complex stress environments. This design improves the stability and fault tolerance of the monitoring system and ensures the continuity and accuracy of dynamic tracking of the oxidation zone.

[0056] Furthermore, existing technologies suffer from the following problems: due to deviations in the nitrogen injection pipeline outlet position and unclear positioning of the monitoring bundle inlet, the switching point is ambiguous. On-site operation relies on manual experience, which can easily lead to misoperation or information lag. This can cause the nitrogen injection area to deviate from the target oxidation zone, resulting in increased nitrogen consumption but poor inerting effect. Additionally, to compensate for monitoring blind spots, multiple monitoring bundles often need to be repeatedly deployed, further increasing material and labor input and reducing overall fire prevention and extinguishing efficiency. Therefore, improvements can be made in pipeline switching and labeling. Specifically, switching points can be clearly marked on the side of the roadway, and each pipeline can be distinguished by color and signage. The burial depth and location information should be dynamically updated to enhance system robustness and maintainability. Figure 4 As shown, Figure 4 A schematic diagram for monitoring the management board of the bundle tube.

[0057] Furthermore, the current system fails to effectively integrate with the intelligent ventilation system, resulting in untimely data feedback and control responses, hindering dynamic optimization management. To address this, this embodiment integrates the monitoring tubes with the intelligent system, enabling real-time acquisition, transmission, and analysis of gas data in the goaf. By establishing a gas concentration change trend model, it automatically identifies abnormal areas and issues warnings. Combining the working face advancement speed and the dynamic evolution of the "three zones" (gas, oxygen, and gas) patterns, the system can intelligently determine the timing and target location for nitrogen injection pipeline switching, guiding precise on-site operations. Simultaneously, unique codes are used to identify each tube bundle and nitrogen injection pipe outlet, achieving precise matching of spatial location with monitoring data and avoiding human error. Relying on a wireless sensing and remote monitoring platform, a closed-loop management system integrating monitoring, decision-making, and control is formed, significantly improving the response speed and operational efficiency of the fire prevention and extinguishing system. By constructing a digital twin model, the evolution of the "three zones" and gas diffusion processes in the goaf are mapped in real time, further enhancing the foresight and accuracy of nitrogen injection path planning and tube bundle layout. Combined with the analysis and processing of historical data, the system can predict oxidation zone migration trends, dynamically optimize pipeline layout parameters and monitoring strategies, reduce human intervention, and lower operation and maintenance costs. Simultaneously, leveraging the Industrial Internet to achieve interconnectivity of underground equipment promotes the transformation of fire prevention and extinguishing management towards automation and intelligence, providing strong support for safe coal mine production. Through multi-source data fusion and edge computing technology, the system can perceive changes in goaf temperature, oxygen concentration, and airflow in real time, dynamically correct the "three-zone" boundary judgment model, and improve the spatiotemporal matching accuracy of nitrogen injection strategies. Combined with deep learning of geological conditions, advance speed, and historical ignition patterns using intelligent algorithms, the system achieves a shift from "passive prevention and control" to "active early warning + precise intervention," significantly reducing the risk of spontaneous combustion and nitrogen consumption. The system can also automatically adjust nitrogen injection flow and pressure based on real-time monitoring data to ensure stable and controllable inerting effects. This drives the development of coal mine fire prevention and extinguishing towards a full-cycle, adaptive, and intelligent approach.

[0058] In summary, the above-mentioned method for burying nitrogen injection pipelines and monitoring bundles in goaf areas provided in this application has the following advantages:

[0059] 1. Highly scientific: Based on the "three zones" theory of goaf, the number of pipelines is calculated through mathematical formulas to avoid human experience errors;

[0060] 2. Wide applicability: Applicable to coal mines with different geological conditions and working face layouts;

[0061] 3. High operability: The calculation is simple and clear, easy to implement on site, and the introduction of rounding up ensures that the number of pipelines covers the entire oxidation zone;

[0062] 4. High reliability: The relationship between the burial spacing and the width of the oxide zone is clearly defined to ensure the continuity of nitrogen injection and monitoring. Through redundant design and spacing control, the system's resistance to damage and monitoring continuity are improved.

[0063] 5. High level of intelligence: It can be integrated with existing intelligent ventilation systems to achieve dynamic control driven by data. According to the actual situation of the coal mining face, the nitrogen injection intensity and monitoring frequency can be dynamically adjusted. By monitoring the gas situation in the goaf collected by the bundle tubes periodically, the development trend of the oxidation zone can be judged, and then the start-up, shutdown and switching of the nitrogen injection pipeline can be guided to achieve precise nitrogen injection and dynamic control. It realizes the systematic and platform-based application of calculation methods and improves the level of intelligent management of coal mines.

[0064] 6. Good economic benefits: It avoids blind pipe laying, saves material and operation and maintenance costs, and improves fire prevention and extinguishing efficiency.

[0065] The above methods have the advantages of being computationally sound, easy to operate, and highly reliable, and can significantly improve the fire prevention and extinguishing capabilities of goaf areas.

[0066] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for burying nitrogen injection pipelines and monitoring bundles in a goaf, characterized in that, include: Obtain the width of the heat dissipation zone and the width of the oxidation zone in the goaf; The number of nitrogen injection lines and the number of monitoring tubes are calculated based on the width of the heat dissipation zone and the width of the oxidation zone. The pipeline laying distance is determined based on the width of the oxide zone, and the pipeline laying distance is not greater than the width of the oxide zone; Based on the number of nitrogen injection pipelines, the number of monitoring bundles, and the pipeline burial spacing, the nitrogen injection pipelines and monitoring bundles are buried. The outlet end of the nitrogen injection pipeline is located within the oxidation zone, and the inlet of the monitoring bundle is located within the oxidation zone. As the coal mining face moves, the heat dissipation zone and the oxidation zone move accordingly. At the same time, the nitrogen injection device is disconnected from the nitrogen injection pipeline that moves out of the oxidation zone, and connected to the next section of the nitrogen injection pipeline that enters the oxidation zone. This process is repeated to ensure that the oxidation zone can be injected with nitrogen at any time. While disconnecting the gas extraction device from the monitoring tube that has been removed from the oxidation zone, connect it to the next section of the monitoring tube that has entered the oxidation zone, and so on, to ensure that the gas concentration in the oxidation zone can be monitored at any time. The calculation of the number of nitrogen injection lines and the number of monitoring tubes based on the width of the heat dissipation zone and the width of the oxidation zone includes: Divide the width of the heat dissipation strip by the width of the oxide strip, round the result up, and add 1 to obtain the number of nitrogen injection lines and the number of monitoring tubes.

2. The method for burying nitrogen injection pipelines and monitoring bundles in goaf areas according to claim 1, characterized in that, The width of the heat dissipation zone and the width of the oxidation zone in the goaf are obtained as follows: Based on a comprehensive assessment of actual on-site measurement data and numerical simulation results, the width of the heat dissipation zone and the width of the oxidation zone in the goaf are determined.

3. The method for burying nitrogen injection pipelines and monitoring bundles in goaf areas according to claim 2, characterized in that, Based on a comprehensive determination using actual on-site measurement data and numerical simulation results, the width of the heat dissipation zone and the width of the oxidation zone in the goaf are obtained as follows: Based on the actual on-site measurement data and the numerical simulation results, the oxygen concentration distribution is determined. The width of the area behind the working face with an oxygen concentration higher than 18% is taken as the width of the heat dissipation zone, and the width of the area with an oxygen concentration between 10% and 18% is taken as the width of the oxidation zone.

4. The method for burying nitrogen injection pipelines and monitoring bundles in goaf areas according to claim 1, characterized in that, The pipeline laying spacing is 0.8 to 1.0 times the width of the oxide zone.

5. The method for burying nitrogen injection pipelines and monitoring bundles in goaf areas according to claim 4, characterized in that, The pipeline laying distance is an integer multiple of the distance between individual pipeline sections.

6. The method for burying nitrogen injection pipelines and monitoring bundles in goaf areas according to claim 1, characterized in that, The nitrogen injection device is a membrane separation nitrogen generator or a pressure swing adsorption nitrogen generator.

7. The method for burying nitrogen injection pipelines and monitoring bundles in goaf areas according to claim 1, characterized in that, The gas extraction device is an intrinsically safe gas sampler for mining.

8. The method for burying nitrogen injection pipelines and monitoring bundles in goaf areas according to claim 1, characterized in that, The nitrogen injection pipeline is a steel pipe with a diameter of 108 mm.

9. The method for burying nitrogen injection pipelines and monitoring bundles in goaf areas according to any one of claims 1-8, characterized in that, It is also equipped with redundant monitoring tubes, with a redundancy of 1 to 2 channels.

Images