Large-scale similar test device and method for spontaneous combustion of gob pressure-bearing gas-containing broken coal

Abstract

The application discloses a goaf pressure-bearing gas-containing broken coal spontaneous combustion large-scale similar test device and method, belongs to the technical field of coal spontaneous combustion test devices, and comprises a sealed test box body, a plurality of simulated goaf test space bodies are arranged in the sealed test box body, a pre-adsorbed gas coal sample tank is arranged in each simulated goaf test space body, and a heating material is laid on the bottom of the simulated goaf test space body below each pre-adsorbed gas coal sample tank; a coal sample release outlet is arranged at the bottom of the pre-adsorbed gas coal sample tank, and a coal sample release gate is arranged on the coal sample release outlet; each pre-adsorbed gas coal sample tank is connected with a gas supply source outside the sealed test box body through a shared gas supply pipeline system, a goaf sensor group is arranged in each simulated goaf test space body, and the goaf sensor group comprises a goaf pressure sensor and a goaf temperature sensor; and the application can more truly and completely simulate the process of goaf pressure-bearing gas-containing broken coal spontaneous combustion.

Description

Technical Field

[0001] This invention belongs to the technical field of coal spontaneous combustion test devices, specifically relating to a large-scale similarity test device and method for spontaneous combustion of crushed coal in a goaf under pressure and containing gas. Background Technology

[0002] As coal seam mining depth increases, the phenomenon of "three highs and one disturbance" becomes increasingly prominent: high ground stress, high ground temperature, high gas content, and mining disturbance. These factors work together to exacerbate the complexity of coal mine safety production, significantly increasing the frequency and severity of disasters such as spontaneous combustion of coal. During coal mining, as the working face advances, the hydraulic supports need to be moved to support new positions. When the working face advances to a certain caving step distance, the exposed roof in the goaf loses support and collapses. The collapsed roof rock (i.e., gangue) mixes with the unmined coal left in the goaf (i.e., residual coal) and accumulates in the goaf, forming a caving zone. In the lower part of this accumulated caving mass or near the bottom of the goaf, the residual coal is subjected to vertical pressure from the upper collapsed gangue and subsequent rock strata subsidence and fracturing. This pressure puts these gas-containing residual coals in a relatively pressurized state. The coal formed by the accumulation and pressurization of residual coal in the goaf, followed by breakage, is called broken coal. In this pressurized state, the adsorbed gas in the gas-containing broken coal in the goaf desorbs and continuously dissipates into the surrounding space and environment. Under the condition of air leakage in the goaf, the broken coal undergoes self-heating oxidation and gradually accumulates sufficient heat. When the heat generated exceeds the heat dissipation, the broken coal continuously heats up, which can lead to coal mine fires or even gas explosions. Therefore, research on the spontaneous combustion characteristics of pressurized gas-containing broken coal in goafs is crucial for preventing underground coal mine fires, gas explosions, and the release of large amounts of toxic and harmful gases, and is directly related to the safe and efficient mining of coal and the safety of miners' lives and property.

[0003] Current research on the spontaneous combustion characteristics of pressurized, gas-bearing, brittle coal in goaf areas largely relies on small-scale physical similarity simulation platforms with high similarity ratios. However, these platforms not only struggle to accurately reproduce the complex environment of goaf areas (such as temperature fields, gas flow, and coal-rock structures), leading to discrepancies between experimental results and actual conditions, but also potentially weaken the evolution of coal spontaneous combustion oxidation kinetics (such as heat and mass transfer rates and the range of oxidation reaction influence) due to spatial limitations, thus affecting the reliability of similar physical simulation experiments. Therefore, large-scale experimental devices can more accurately simulate the multi-field coupling effects (temperature-airflow-coal oxidation interactions) in actual goaf areas, capturing the evolutionary laws of coal spontaneous combustion under complex environments and enhancing its engineering application value. To more realistically and completely simulate the spontaneous combustion process of pressurized, gas-bearing, brittle coal in goaf areas, there is an urgent need to develop a large-scale similarity experimental device and method for the spontaneous combustion of pressurized, gas-bearing, brittle coal in goaf areas. Summary of the Invention

[0004] This invention addresses the problem that existing small-scale physical similarity simulation test platforms with high similarity ratios cannot realistically reproduce the complex environment and small spatial scale of goaf areas. It overcomes the shortcomings of existing technologies by providing a large-scale similarity test device and method for spontaneous combustion of pressurized, gas-bearing, crushed coal in goaf areas. This invention can more realistically and completely simulate the process of spontaneous combustion of pressurized, gas-bearing, crushed coal in goaf areas.

[0005] To achieve the above objectives, the present invention adopts the following technical solution.

[0006] A large-scale similarity test device for spontaneous combustion of crushed coal under pressure and containing gas in goaf includes a sealed test chamber. Multiple simulated goaf test spaces are arranged inside the sealed test chamber. Each simulated goaf test space is equipped with a pre-adsorbed gas coal sample tank. The bottom of the simulated goaf test space below each pre-adsorbed gas coal sample tank is covered with heating material. The bottom of the pre-adsorbed gas coal sample tank is equipped with a coal sample release outlet, and a coal sample release gate is installed on the coal sample release outlet. A distance is left between the coal sample release outlet and the top surface of the heating material. Each pre-adsorbed gas coal sample tank is connected to the gas supply source outside the sealed test chamber through a shared gas supply pipeline system. Each simulated goaf test space is equipped with a goaf sensor group, which includes a goaf pressure sensor and a goaf temperature sensor. The experimental apparatus also includes a main control system, a data acquisition system, and a PC. The main control system, data acquisition system, and PC are all located outside the sealed test chamber. The goaf sensor group is connected to the data acquisition system, and the main control system and data acquisition system are both connected to the PC. The main control system is connected to the coal sample release gate and is used to control the automatic opening and closing of the coal sample release gate, thereby placing the gas-containing coal sample in the pre-adsorbed gas coal sample tank above the heating material.

[0007] Furthermore, the test apparatus also includes a ventilation system, which consists of a return air duct, an intake air duct, and a fan. The return air duct and the intake air duct are both connected to the inside of the sealed test chamber, and the fan is connected to the return air duct. The ventilation system provides sufficient oxygen to each simulated goaf test space inside the sealed test chamber.

[0008] Furthermore, each simulated goaf test space is equipped with a goaf gas collection pipe, which is connected to a gas analysis device located outside the sealed test chamber.

[0009] Furthermore, each simulated goaf test space is filled with collapsed coal and rock mass, which is fixed above the heating material. A pre-adsorbed gas coal sample container is fixed through the middle of the collapsed coal and rock mass, with both the upper and lower parts of the pre-adsorbed gas coal sample container exposed above the collapsed coal and rock mass. A space is left between the collapsed coal and rock mass and the heating material for laying the gas-containing coal sample released from the pre-adsorbed gas coal sample container. The space above the collapsed coal and rock mass and the space below the collapsed coal and rock mass are ventilated.

[0010] Furthermore, a three-way valve is installed at the center of the top of the pre-adsorbed gas coal sample tank. One port of the three-way valve is connected to the pre-adsorbed gas coal sample tank, and the other two ports of the three-way valve are connected to the gas inlet connection pipe, which is connected to the gas supply pipeline system. A tank pressure sensor and a tank temperature sensor are also installed on the top of the pre-adsorbed gas coal sample tank, and both the tank pressure sensor and the tank temperature sensor are connected to the data acquisition system. A heating and insulation box is installed outside the pre-adsorbed gas coal sample tank.

[0011] Furthermore, the top of the pre-adsorbed gas coal sample container is also provided with a coal sample filling port, and a sealing cap is provided on the coal sample filling port.

[0012] Furthermore, the gas supply pipeline system is equipped with a gas flow meter, and both the gas flow meter and the three-way valve are connected to the main control system.

[0013] Furthermore, the main control system adopts a PLC controller.

[0014] Furthermore, the data acquisition system includes a data acquisition unit, a signal amplification board, and an acquisition control board. The goaf sensor group, tank pressure sensor, tank temperature sensor, and gas analysis device are all connected to the data acquisition unit. The data acquisition unit is connected to the signal amplification board, the signal amplification board is connected to the acquisition control board, and the acquisition control board is connected to a PC.

[0015] The large-scale similarity test method for spontaneous combustion of gas-bearing fractured coal in goaf provided by this invention is implemented using the aforementioned large-scale similarity test device for spontaneous combustion of gas-bearing fractured coal in goaf, and includes the following steps: Step 1: First, load the coal sample into the pre-adsorbed gas coal sample container. Introduce gas at a preset temperature and pressure into the container via a gas supply source. Start the heating and insulation box to heat the container. During the gas introduction process, the temperature and pressure of the container are monitored in real time by pressure and temperature sensors. After stopping the gas introduction, close the three-way valve to maintain a sealed container. Pre-adsorb for 24 hours. Once the temperature and pressure inside the container stabilize, the gas is successfully embedded in the coal sample. Step 2: Then, the main control system controls the coal sample release gate to open, releasing the gas-containing coal sample onto the heating material. The coal sample released onto the heating material forms gas-containing crushed coal. The gas-containing crushed coal comes into contact with the heating material and reacts with the heating material to generate a large amount of heat. The gas-containing crushed coal heats up, and the gas begins to desorb. Step 3: Start the ventilation system fan again and introduce air through the air intake pipe to provide sufficient oxygen for the heating and oxidation of the crushed coal in each simulated goaf test space. The crushed coal completes the oxidation process when it comes into contact with oxygen, and when the heat accumulates to the ignition point of the crushed coal, the crushed coal spontaneously combusts. Step 4: The temperature and pressure inside each simulated goaf test space are measured by goaf pressure sensor and goaf temperature sensor. Gas inside each simulated goaf test space is collected by goaf gas collection pipeline and transported to gas analysis device. Finally, the temperature, pressure and gas concentration data inside the simulated goaf test space are transmitted to PC for data processing to obtain the time-varying trend of parameters of crushed coal heating and oxidation process.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: The large-scale similarity test device and method for spontaneous combustion of crushed coal under pressure and containing gas in goaf provided by this invention forms a large-scale test device by setting up multiple simulated goaf test spaces in a sealed test chamber. It is equipped with a pre-adsorbed gas coal sample tank, a main control system, a data acquisition system, and a PC, realizing intelligent control of the entire test process. It can reflect the significant advantages in simulating the influence of gas on the spontaneous combustion of crushed coal in goaf. It can more realistically and completely simulate the process of spontaneous combustion of crushed coal under pressure and containing gas in goaf, providing a more scientific experimental basis for safe coal mine production. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the large-scale similarity test device for spontaneous combustion of crushed coal under pressure and containing gas in the goaf of the present invention. Figure 2 This is a schematic diagram of the internal enlarged structure of a single test space of the large-scale similar test device for spontaneous combustion of crushed coal under pressure and containing gas in the goaf of the present invention; Figure 3 This is a schematic diagram of the pre-adsorbed gas coal sample tank of the large-scale similarity test device for spontaneous combustion of crushed coal under pressure in goaf areas according to the present invention.

[0018] The diagram is labeled as follows: 1-Return air duct; 2-Inlet air duct; 3-Gas supply pipeline system; 4-Simulated goaf test space; 41-Tank pressure sensor; 42-Heating and insulation box; 43-Pre-adsorbed gas coal sample tank; 44-Goaf sensor group; 45-Heating material; 46-Gas-containing crushed coal; 47-Collapsed coal and rock mass; 48-Tank temperature sensor; 49-Three-way valve; 410-Gas inlet connection pipe; 431-Coal sample release outlet; 432-Coal sample release gate; 433-Sealing cover. Detailed Implementation

[0019] To make the technical problems solved, the technical solutions, and the beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0020] Combination Figures 1 to 3 As shown in the embodiment of the present invention, a large-scale similarity test device for spontaneous combustion of crushed coal under pressure and containing gas in a goaf includes a sealed test chamber. Multiple simulated goaf test spaces 4 are arranged inside the sealed test chamber. Each simulated goaf test space 4 contains a pre-adsorbed gas coal sample container 43. A heating material 45, 3 cm thick, is laid at the bottom of each simulated goaf test space 4 below the pre-adsorbed gas coal sample container 43 to promote spontaneous combustion of the coal sample. A coal sample release outlet 431 is provided at the bottom of the pre-adsorbed gas coal sample container 43, and a coal sample release gate 432 is provided on the coal sample release outlet 431. A distance is left between the coal sample release outlet 431 and the top surface of the heating material 45. The distance is set to 30cm; each pre-adsorbed gas coal sample tank 43 is connected to the gas supply source outside the sealed test chamber through a shared gas supply pipeline system 3. Each simulated goaf test space 4 is equipped with a goaf sensor group 44, which includes a goaf pressure sensor and a goaf temperature sensor. The test device also includes a main control system, a data acquisition system, and a PC. The main control system, data acquisition system, and PC are all located outside the sealed test chamber. The goaf sensor group 44 is connected to the data acquisition system, and the main control system and data acquisition system are both connected to the PC. The main control system is connected to the coal sample release gate 432 and is used to control the automatic opening and closing of the coal sample release gate 432, thereby releasing the gas-containing coal sample in the pre-adsorbed gas coal sample tank 43 onto the heating material 45.

[0021] Specifically, the test apparatus also includes a ventilation system, which consists of a return air duct 1, an inlet air duct 2, and a ventilator. Both the return air duct 1 and the inlet air duct 2 are connected to the inside of the sealed test chamber, and the ventilator is connected to the return air duct 1. The ventilation system provides sufficient oxygen to each simulated goaf test space 4 inside the sealed test chamber.

[0022] Specifically, each simulated goaf test space 4 is also equipped with a goaf gas collection pipe, which is connected to a gas analysis device located outside the sealed test chamber.

[0023] Specifically, each simulated goaf test space 4 is filled with collapsed coal and rock mass 47, which is fixed above the heating material 45. A pre-adsorbed gas coal sample container 43 is fixed through and fixed in the middle of the collapsed coal and rock mass 47, with both the upper and lower parts of the pre-adsorbed gas coal sample container 43 exposed above the collapsed coal and rock mass 47. A space is left between the collapsed coal and rock mass 47 and the heating material 45 for laying the gas-containing coal sample released from the pre-adsorbed gas coal sample container 43. The space above the collapsed coal and rock mass 47 and the space below the collapsed coal and rock mass 47 are ventilated. Based on the basic characteristics of goaf areas, this invention selects suitable filling material, collapsed coal and rock mass 47, and fills it in the simulated goaf test space 4 to meet experimental requirements and better simulate goaf areas.

[0024] Specifically, a three-way valve 49 is installed at the center of the top of the pre-adsorbed gas coal sample tank 43. One port of the three-way valve 49 is connected to the pre-adsorbed gas coal sample tank 43, and the other two ports of the three-way valve 49 are connected to the gas inlet connection pipe 410. The gas inlet connection pipe 410 is connected to the gas supply pipeline system 3. A tank pressure sensor 41 and a tank temperature sensor 48 are also installed on the top of the pre-adsorbed gas coal sample tank 43. Both the tank pressure sensor 41 and the tank temperature sensor 48 are connected to the data acquisition system. A heating and insulation box 42 is installed outside the pre-adsorbed gas coal sample tank 43. The pre-adsorbed gas coal sample tank 43 is made of 316 stainless steel and has pressure resistance. The heating and insulation box 42 can provide heat to the coal sample in the pre-adsorbed gas coal sample tank 43 to raise the temperature of the coal sample and maintain the temperature.

[0025] Specifically, the top of the pre-adsorbed gas coal sample container 43 is also provided with a coal sample filling port, and a sealing cap 433 is provided on the coal sample filling port.

[0026] Specifically, a gas flow meter is installed on the gas supply pipeline system 3, and the gas flow meter and the three-way valve 49 are both connected to the main control system. The main control system is used to control the operation of the gas flow meter and the three-way valve 49, and the gas flow meter is used to detect the flow rate of gas supplied to the pre-adsorbed gas coal sample tank 43 through the gas supply pipeline system 3 in real time.

[0027] Specifically, the main control system adopts a PLC controller.

[0028] Specifically, the data acquisition system includes a data acquisition unit, a signal amplification board, and an acquisition control board. The goaf sensor group 44, the tank pressure sensor 41, the tank temperature sensor 48, and the gas analysis device are all connected to the data acquisition unit. The data acquisition unit is connected to the signal amplification board, the signal amplification board is connected to the acquisition control board, and the acquisition control board is connected to a PC. The PC is also connected to a printer for convenient real-time printing of the required data.

[0029] The present invention provides a large-scale similarity test method for spontaneous combustion of gas-bearing crushed coal in a goaf, comprising the following steps; Step 1: First, take three coal samples of different particle sizes, namely large, medium, and small, to simulate the compaction of the "O"-shaped ring in the goaf. Load the coal samples into the pre-adsorbed gas coal sample tank 43. Introduce gas at a preset temperature and pressure into the pre-adsorbed gas coal sample tank 43 through a gas supply source. Start the heating and insulation box 42 to heat the pre-adsorbed gas coal sample tank 43. During the gas introduction process, the tank pressure sensor 41 and tank temperature sensor 48 monitor the temperature and pressure of the pre-adsorbed gas coal sample tank 43 in real time. After stopping the gas introduction, close the three-way valve 49 to keep the pre-adsorbed gas coal sample tank 43 sealed. After 24 hours of pre-adsorption, once the temperature and pressure inside the pre-adsorbed gas coal sample tank 43 have stabilized, the gas has successfully embedded itself into the coal sample. Step 2: Then, the main control system controls the coal sample release gate 432 to open, releasing the gas-containing coal sample onto the heating material 45. The coal sample released onto the heating material 45 forms gas-containing crushed coal 46. The gas-containing crushed coal 46 comes into contact with the heating material 45 and reacts with the heating material 45 to generate a large amount of heat. The gas-containing crushed coal 46 heats up, and the gas begins to desorb. Step 3: Start the ventilation system fan again and introduce air through the air inlet pipe 2 to provide sufficient oxygen for the heating and oxidation of the crushed coal in each simulated goaf test space 4. The crushed coal comes into contact with oxygen to complete the oxidation process, and when the heat accumulates to the ignition point of the crushed coal, the crushed coal will spontaneously combust. Step 4: The temperature and pressure inside each simulated goaf test space 4 are measured by goaf pressure sensors and goaf temperature sensors. Gas is collected from each simulated goaf test space 4 by goaf gas collection pipeline and transported to the gas analysis device. Finally, the temperature, pressure, and gas concentration data inside the simulated goaf test space 4 are transmitted to the PC for data processing to obtain the trend of parameters of the crushed coal heating and oxidation process over time. The entire experimental process can be controlled by operating the PC.

[0030] In summary, (1) the large-scale similarity test device for spontaneous combustion of gas-bearing crushed coal in goaf proposed in this invention has the ability to simulate the actual coal sample occurrence environment under different temperature and pressure conditions. This is of great experimental value for studying the adsorption and desorption characteristics of coal, analyzing spontaneous combustion tendency, and verifying theoretical models. Through the pre-adsorbed gas coal sample tank 43, the physical and chemical change processes of coal under various environments can be understood and mastered more accurately. (2) A significant advantage of this invention is that the gas-bearing crushed coal 46 formed by releasing the coal sample onto the heating material 45 through the pre-adsorbed gas coal sample tank 43 simulates the adsorption, desorption, heating, oxidation, and spontaneous combustion process of the coal sample in the pre-adsorbed gas coal sample tank 43, and more comprehensively reproduces the process of spontaneous combustion of crushed coal in goaf. (3) Another significant advantage of the present invention is that it can simulate the entire process of coal adsorption, desorption, oxidation and heating in the goaf by using multiple simulated goaf test spaces in a sealed test chamber. In this way, experimental data that is closer to real conditions can be provided, thereby supporting the verification and optimization of prevention and control technologies. (4) In the present invention, the heating material 45 used can ensure that the gas-containing crushed coal 46 is heated evenly throughout the experiment. This uniform heating method can better simulate the situation of coal heating and spontaneous combustion in the goaf environment, thereby providing a more reliable experimental basis for studying the spontaneous combustion mechanism and prevention measures of coal.

[0031] It is understood that, although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A large-scale similarity test device for spontaneous combustion of crushed coal in a goaf under pressure and containing gas, characterized in that: It includes a sealed test chamber, which contains multiple simulated goaf test spaces. Each simulated goaf test space contains a pre-adsorbed gas coal sample tank, and the bottom of each simulated goaf test space below the pre-adsorbed gas coal sample tank is covered with heating material. The bottom of the pre-adsorbed gas coal sample tank is equipped with a coal sample release outlet, and a coal sample release gate is installed on the coal sample release outlet. A distance is left between the coal sample release outlet and the top surface of the heating material. Each pre-adsorbed gas coal sample tank is connected to the gas supply source outside the sealed test chamber through a shared gas supply pipeline system. Each simulated goaf test space is equipped with a goaf sensor group, which includes a goaf pressure sensor and a goaf temperature sensor. The experimental apparatus also includes a main control system, a data acquisition system, and a PC. The main control system, data acquisition system, and PC are all located outside the sealed test chamber. The goaf sensor group is connected to the data acquisition system, and the main control system and data acquisition system are both connected to the PC. The main control system is connected to the coal sample release gate and is used to control the automatic opening and closing of the coal sample release gate, thereby placing the gas-containing coal sample in the pre-adsorbed gas coal sample tank above the heating material. A three-way valve is installed at the center of the top of the pre-adsorbed gas coal sample tank. One port of the three-way valve is connected to the pre-adsorbed gas coal sample tank, and the other two ports are connected to the gas inlet connection pipe, which is connected to the gas supply pipeline system. A tank pressure sensor and a tank temperature sensor are also installed on the top of the pre-adsorbed gas coal sample tank, and both of them are connected to the data acquisition system. A heating and insulation box is installed outside the pre-adsorbed gas coal sample tank.

2. The large-scale similarity test device for spontaneous combustion of crushed coal in a goaf under pressure and containing gas, as described in claim 1, is characterized in that: The test apparatus also includes a ventilation system, which consists of a return air duct, an intake air duct, and a fan. The return air duct and the intake air duct are connected to the inside of the sealed test chamber, and the fan is connected to the return air duct. The ventilation system provides sufficient oxygen to each simulated goaf test space inside the sealed test chamber.

3. The large-scale similarity test device for spontaneous combustion of crushed coal in a goaf under pressure and containing gas, as described in claim 2, is characterized in that: Each simulated goaf test space is also equipped with a goaf gas collection pipeline, which is connected to a gas analysis device located outside the sealed test chamber.

4. The large-scale similarity test device for spontaneous combustion of crushed coal in a goaf under pressure and containing gas, as described in claim 3, is characterized in that: Each simulated goaf test space is filled with collapsed coal and rock mass, which is fixed above the heating material. A pre-adsorbed gas coal sample container is fixed through the middle of the collapsed coal and rock mass, with both the upper and lower parts of the pre-adsorbed gas coal sample container exposed above the collapsed coal and rock mass. A space is left between the collapsed coal and rock mass and the heating material for laying the gas-containing coal sample released from the pre-adsorbed gas coal sample container. The space above the collapsed coal and rock mass and the space below the collapsed coal and rock mass are ventilated.

5. The large-scale similarity test device for spontaneous combustion of crushed coal in a goaf under pressure and containing gas, as described in claim 4, is characterized in that: The top of the pre-adsorbed gas coal sample container is also equipped with a coal sample filling port, and a sealing cap is provided on the coal sample filling port.

6. The large-scale similarity test device for spontaneous combustion of crushed coal in a goaf under pressure and containing gas, as described in claim 5, is characterized in that: The gas supply pipeline system is equipped with a gas flow meter, and both the gas flow meter and the three-way valve are connected to the main control system.

7. The large-scale similarity test device for spontaneous combustion of crushed coal in a goaf under pressure and containing gas, as described in claim 6, is characterized in that: The main control system uses a PLC controller.

8. The large-scale similarity test device for spontaneous combustion of crushed coal in a goaf under pressure and containing gas, as described in claim 7, is characterized in that: The data acquisition system includes a data acquisition unit, a signal amplifier board, and an acquisition control board. The goaf sensor group, tank pressure sensor, tank temperature sensor, and gas analysis device are all connected to the data acquisition unit. The data acquisition unit is connected to the signal amplifier board, the signal amplifier board is connected to the acquisition control board, and the acquisition control board is connected to a PC.

9. A large-scale similarity test method for spontaneous combustion of confined coal in a goaf under pressure and containing gas, implemented using the large-scale similarity test device for spontaneous combustion of confined coal in a goaf under pressure and containing gas as described in claim 8, characterized in that: Includes the following steps: Step 1: First, load the coal sample into the pre-adsorbed gas coal sample container. Introduce gas at a preset temperature and pressure into the container via a gas supply source. Start the heating and insulation box to heat the container. During the gas introduction process, the temperature and pressure of the container are monitored in real time by pressure and temperature sensors. After stopping the gas introduction, close the three-way valve to maintain a sealed container. Pre-adsorb for 24 hours. Once the temperature and pressure inside the container stabilize, the gas is successfully embedded in the coal sample. Step 2: Then, the main control system controls the coal sample release gate to open, releasing the gas-containing coal sample onto the heating material. The coal sample released onto the heating material forms gas-containing crushed coal. The gas-containing crushed coal comes into contact with the heating material and reacts with the heating material to generate a large amount of heat. The gas-containing crushed coal heats up, and the gas begins to desorb. Step 3: Start the ventilation system fan again and introduce air through the air intake pipe to provide sufficient oxygen for the heating and oxidation of the crushed coal in each simulated goaf test space. The crushed coal completes the oxidation process when it comes into contact with oxygen, and when the heat accumulates to the ignition point of the crushed coal, the crushed coal spontaneously combusts. Step 4: The temperature and pressure inside each simulated goaf test space are measured by goaf pressure sensor and goaf temperature sensor. Gas inside each simulated goaf test space is collected by goaf gas collection pipeline and transported to gas analysis device. Finally, the temperature, pressure and gas concentration data inside the simulated goaf test space are transmitted to PC for data processing to obtain the time-varying trend of parameters of crushed coal heating and oxidation process.

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