Experimental device and method for simulating the spontaneous combustion and extinction process of coal in a closed fire area

Abstract

An experimental device and method for simulating the spontaneous combustion and extinguishing process of coal in a closed fire area, wherein the experimental device includes a coal body simulation system, a fire monitoring system, a fire extinguishing simulation system and a sewage treatment system, wherein the fire monitoring system includes a chromatograph, a nitrogen source, an oxygen source, and a plurality of thermocouples and a plurality of gas intakes embedded in the coal body and distributed at different positions; the fire extinguishing simulation system includes a fire extinguishing agent source, which is used to provide a gaseous fire extinguishing agent and pass it into the coal body from the bottom of the experimental box, or to provide a solid fire extinguishing agent or a liquid fire extinguishing agent and pass it into the coal body from the top of the experimental box; the sewage treatment system includes a gas sewage treatment subsystem and a liquid sewage treatment subsystem to treat the gas overflowing from the coal body, and to treat the liquid flowing out of the coal body. The present invention is easy to use and operate, can simulate the entire process of spontaneous combustion and extinguishing of coal, and can truly reflect the inhibitory effect of different fire extinguishing materials on different coal bodies.

Description

Technical Field

[0001] The invention relates to the technical field of coal spontaneous combustion and fire extinguishing experiments, and in particular to an experimental device and method for simulating the spontaneous combustion and extinguishing process of coal in a closed fire area. Background Art

[0002] my country has always been the world's largest coal producer and consumer. In 2021, my country's coal production has reached 4.07 billion tons. Coal spontaneous combustion, as one of the main disasters in coal production, mainly occurs in hidden places such as goafs and fracturing coal pillars. There are problems such as difficulty in detecting spontaneous combustion in the early stage, difficulty in determining the location of high-temperature areas, and targeted use of fire-fighting materials. For external fires in mines, the method of inert injection is generally used to extinguish the fire. However, for coal mines with complex conditions, re-ignition accidents often occur when the fire zone is unsealed, which can easily cause casualties and property losses. At present, there is a lack of experimental research on simulating coal spontaneous combustion and coal body cooling. Therefore, the targeted and efficient use of fire-extinguishing materials for the initial extinguishing of fires and blocking the conditions for re-ignition is an important topic of current research and is of great significance to coal mining. Summary of the invention

[0003] In order to solve the above-mentioned technical problems existing in the prior art, the present invention provides an experimental device and method for simulating the spontaneous combustion and extinction process of coal in a closed fire area. The experimental device is easy to use and operate, can simulate the entire process of spontaneous combustion and extinction of coal, and can truly reflect the inhibitory effect of different fire extinguishing materials on different coal bodies.

[0004] To achieve the above object, the present invention provides an experimental device for simulating the spontaneous combustion and extinguishing process of coal in a closed fire area, which includes a coal body simulation system, a fire monitoring system, a fire extinguishing simulation system and a sewage treatment system, wherein:

[0005] The coal simulation system comprises an experimental box which is sealed inside and filled with coal;

[0006] The fire monitoring system includes a chromatograph, a nitrogen source, an oxygen source, and a plurality of thermocouples and gas outlets embedded in the coal body and distributed at different positions. The sampling tube of the chromatograph is connected to a gas collecting bottle, and the gas collecting bottle is connected to the gas outlet through a gas sampling tube. The nitrogen source and the oxygen source provide nitrogen and oxygen respectively and are introduced into the coal body from the bottom of the experimental box.

[0007] The fire extinguishing simulation system includes a fire extinguishing agent source, which is used to provide a gaseous fire extinguishing agent and pass it into the coal body from the bottom of the experimental box, or to provide a solid fire extinguishing agent or a liquid fire extinguishing agent and pass it into the coal body from the top of the experimental box;

[0008] The sewage treatment system includes a gas sewage treatment subsystem and a liquid sewage treatment subsystem. The gas sewage treatment subsystem is connected to the top of the experimental box to treat the gas overflowing from the coal body, and the liquid sewage treatment subsystem is connected to the bottom of the experimental box to treat the liquid flowing out from the coal body.

[0009] As a further preferred technical solution of the present invention, the experimental box is a rectangular structure with a detachable sealing cover connected to the top, and a mesh is provided between the sealing cover and the top of the coal body; the thermocouples and the gas intake ports are both inserted into the coal body after passing through the side walls of the experimental box, and each side wall corresponds to at least two thermocouples and at least two gas intake ports; the gas production pipe is connected to a gas production flow valve and a gas production flow meter.

[0010] As a further preferred technical solution of the present invention, a thermal insulation interlayer is arranged around the experimental box, the thermal insulation interlayer is filled with heat insulation or thermal insulation materials, and the thermal insulation interlayer is also provided with an electric heating wire.

[0011] As a further preferred technical solution of the present invention, a bottom pipeline located at the bottom of the coal body is buried in the experimental box, and a plurality of holes are provided on the bottom pipeline in the shape of a sieve. The bottom pipeline is connected to a connecting pipe that passes through the bottom plate of the experimental box and extends out. The gaseous fire extinguishing agent provided by the fire extinguishing agent source, and the nitrogen and oxygen provided by the nitrogen source and the oxygen source respectively are input into the experimental box through the connecting pipe, and the liquid in the experimental box flows out to the liquid sewage treatment subsystem through the connecting pipe.

[0012] As a further preferred technical solution of the present invention, the fire monitoring system also includes a gas mixing box, the output end of the gas mixing box is connected to the connecting pipe through a gas supply pipeline, and the nitrogen source and the oxygen source are connected to the input end of the gas mixing box through a nitrogen branch pipe and an oxygen branch pipe respectively; a nitrogen decompression valve and a nitrogen flowmeter are provided on the nitrogen branch pipe, and an oxygen decompression valve and an oxygen flowmeter are provided on the oxygen branch pipe, and a spiral blade for stirring and mixing nitrogen and oxygen is also provided in the gas mixing box.

[0013] As a further preferred technical solution of the present invention, the fire extinguishing simulation system also includes a fire extinguishing agent mixing box, the input end of the fire extinguishing agent mixing box is connected to the fire extinguishing agent source, the output end of the fire extinguishing agent mixing box is connected to a fire extinguishing agent output main pipe, the output end of the fire extinguishing agent output main pipe is connected to a gas fire extinguishing agent output branch pipe and a solid-liquid fire extinguishing agent output branch pipe through a branch, the gas fire extinguishing agent output branch pipe is connected to the connecting pipe, and the solid-liquid fire extinguishing agent output branch pipe is connected to the top of the experimental box body; there are two fire extinguishing agent sources, namely a gas fire extinguishing agent source for providing gas fire extinguishing agent, and a solid-liquid fire extinguishing agent source for providing solid or liquid fire extinguishing agent; a pressure pump and a fire extinguishing agent flow meter are provided on the fire extinguishing agent output main pipe, and the gas fire extinguishing agent output branch pipe and the solid-liquid fire extinguishing agent output branch pipe are respectively connected to a gas fire extinguishing agent flow valve and a solid-liquid fire extinguishing agent flow valve.

[0014] As a further preferred technical solution of the present invention, the liquid sewage treatment subsystem includes a liquid recovery device, which is connected to the connecting pipe, and a pressure valve is provided in the pipeline between the connecting pipe and the liquid recovery device. The liquid recovery device is also connected to the fire extinguishing agent mixing tank, and a valve is provided in the pipeline between the liquid recovery device and the fire extinguishing agent mixing tank.

[0015] As a further preferred technical solution of the present invention, the gas wastewater treatment subsystem includes a waste gas treatment bottle, the waste gas pipeline of the waste gas treatment bottle is connected to the top of the experimental box, and a waste gas flow valve is provided in the waste gas pipeline.

[0016] According to another aspect of the present invention, the present invention also provides an experimental method for simulating the spontaneous combustion and extinction process of coal in a closed fire zone, comprising the following steps:

[0017] 1) Fill the experimental box with coal samples to form a coal body, and bury multiple thermocouples and multiple gas inlets in the coal body in a dispersed manner, and seal the experimental box. Then, connect the fire monitoring system, the fire extinguishing simulation system, and the sewage treatment system to the coal body simulation system respectively and ensure the sealing of the connection;

[0018] 2) starting the fire monitoring system, providing nitrogen and oxygen from a nitrogen source and an oxygen source respectively to form a mixed gas and passing it into the coal body from the bottom of the experimental box, collecting the gas discharged from the gas inlet in real time by a chromatograph and monitoring the temperature in the coal body in real time by a thermocouple, and comprehensively judging the degree of spontaneous combustion of the coal body;

[0019] 3) When it is determined that the coal body is spontaneously ignited and reaches the preset fire extinguishing conditions, the fire extinguishing simulation system is started, and the fire extinguishing agent source provides gaseous fire extinguishing agent and passes it into the coal body from the bottom of the experimental box, or provides solid fire extinguishing agent or liquid fire extinguishing agent and passes it into the coal body from the top of the experimental box until the fire is extinguished;

[0020] When executing steps 2) and 3, the gas overflowing from the coal body is treated by the gas sewage treatment subsystem of the sewage treatment system, and at the same time, the liquid sewage treatment subsystem of the sewage treatment system treats the liquid flowing out of the coal body.

[0021] As a further preferred technical solution of the present invention, after using solid fire extinguishing agent or liquid fire extinguishing agent for fire extinguishing, the liquid sewage treatment subsystem recovers the liquid containing the fire extinguishing agent and then delivers it to the fire extinguishing simulation system so that the fire extinguishing simulation system can reuse the recovered fire extinguishing agent.

[0022] The present invention can conduct a spontaneous combustion oxidation temperature rise simulation experiment based on coal samples taken from a closed fire area in a coal seam, and determine the spontaneous combustion index gas and the shortest spontaneous combustion period by analyzing the change pattern of gas generation and concentration with temperature during the experiment, which can provide an important reference basis for the prediction of spontaneous combustion of coal seams and targeted technical prevention and control.

[0023] The experimental device and method for simulating the spontaneous combustion and extinction process of coal in a closed fire zone of the present invention adopt the above technical scheme, which can achieve the following beneficial effects:

[0024] 1) The device for simulating the natural ignition and extinction process of coal in a closed fire zone of the present invention has a simple structure, a novel and reasonable design, convenient experiments and low costs;

[0025] 2) The device for simulating the natural combustion and extinguishing process of coal in a closed fire zone of the present invention is easy to use and operate, can simulate the entire process of natural combustion and extinguishing of coal, can truly reflect the inhibitory effect of different fire extinguishing materials on different coal bodies, and solves the drawback of the prior art that it can only simulate the natural combustion or extinguishing process of coal in a one-way manner;

[0026] 3) The device of the present invention simulates the natural ignition and extinguishing process of coal in a closed fire area. By measuring the temperature, the temperature changes at different positions of the coal body can be detected, so that the most reasonable fire extinguishing materials can be used to extinguish the fire and the effect can be observed;

[0027] 4) The device for simulating the natural ignition and extinguishing process of coal in a closed fire zone of the present invention is provided with a flow meter and a mixing device, which can realize the control of the amount of gas used in the heating process and the amount of fire extinguishing material used in the fire extinguishing process, and has the effect of saving economy;

[0028] 5) The method for simulating the spontaneous combustion and extinction process of coal in a closed fire zone of the present invention has simple steps and is easy to implement. The recorded experimental data can be used to establish a relevant coal spontaneous combustion model, which has guiding significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0030] Figure 1 A schematic structural diagram of an example of an experimental device for simulating the spontaneous combustion and extinction process of coal in a closed fire zone provided by the present invention;

[0031] Figure 2 It is a schematic diagram of the internal structure of the experimental box of the present invention when viewed from above.

[0032] In the figure: 1—thermocouple; 2—gas inlet; 3—water; 4—coal body; 5—sealing cover; 6—mesh; 7—waste gas flow valve; 8—gas flow valve; 9—gas extinguishing agent flow valve; 10—solid-liquid extinguishing agent flow valve; 11—nitrogen decompression valve; 12—extinguishing agent flow meter; 13—nitrogen flow meter; 14—oxygen flow meter; 15—gas mixing box; 16—spiral blade; 17—oxygen source; 18—nitrogen source; 19—nitrogen branch pipe; 20— Oxygen branch pipe; 21-pressure pump; 22-mixed fire extinguishing agent; 23-fire extinguishing agent mixing box; 24-gas fire extinguishing agent source; 25-solid-liquid fire extinguishing agent source; 26-gas flow meter; 27-gas collecting bottle; 28-chromatograph; 29-waste gas treatment bottle; 30-fire extinguishing agent output main pipe; 31-gas collection pipe; 32-waste gas pipeline; 33-bottom pipeline; 34-valve; 35-recovery device; 36-pressure valve; 37-connecting pipe; 38-electric heating wire.

[0033] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings in conjunction with the embodiments. DETAILED DESCRIPTION

[0034] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. The terms such as "upper", "lower", "left", "right", "middle" and "one" cited in the preferred embodiments are only for the convenience of description, and are not used to limit the scope of the present invention. The change or adjustment of the relative relationship shall also be regarded as the scope of the present invention without substantially changing the technical content.

[0035] like Figure 1 As shown, the present invention provides an experimental device for simulating the natural ignition and extinction process of coal in a closed fire area, including a coal body 4 simulation system, a fire monitoring system, a fire extinguishing simulation system and a sewage treatment system.

[0036] The coal body 4 simulation system comprises an experimental box which is sealed inside and filled with coal body 4 . The experimental box is a rectangular parallelepiped structure with a detachable sealing cover 5 connected to the top. A mesh 6 is provided between the sealing cover 5 and the top of the coal body 4 .

[0037] The fire monitoring system includes a chromatograph 28, a nitrogen source 18, an oxygen source 17, and a plurality of thermocouples 1 and gas outlets 2 embedded in the coal body 4 and distributed at different positions. The gas outlets 2 distributed at different positions can be used to collect gas samples from different positions in the coal body 4, and the thermocouples 1 distributed at different positions can be used to collect the temperature of different positions in the coal body 4. The sampling tube of the chromatograph 28 is connected to a gas collecting bottle 27, and the gas collecting bottle 27 is connected to the gas outlet 2 through a gas sampling tube 31. The nitrogen source 18 and the oxygen source 17 provide nitrogen and oxygen, respectively, and are introduced into the coal body 4 from the bottom of the experimental box. The gas sampling tube 31 is connected to a gas flow valve 8 and a gas flow meter 26. The thermocouples 1 and the gas outlets 2 are both inserted into the coal body 4 after passing through the side walls of the experimental box, and each side wall corresponds to at least two thermocouples 1 and at least two gas outlets 2. In this embodiment, refer to Figure 2 As shown, each side corresponds to two thermocouples 1 and two air intake ports 2 .

[0038] The fire extinguishing simulation system includes a fire extinguishing agent source, which is used to provide a gas fire extinguishing agent and pass it into the coal body 4 from the bottom of the experimental box, or to provide a solid fire extinguishing agent or a liquid fire extinguishing agent and pass it into the coal body 4 from the top of the experimental box. It should be noted that the gas fire extinguishing agent, solid fire extinguishing agent or liquid fire extinguishing agent in this application can be selected according to different experimental requirements and is not limited here.

[0039] The sewage treatment system includes a gas sewage treatment subsystem and a liquid sewage treatment subsystem. The gas sewage treatment subsystem is connected to the top of the experimental box to treat the gas overflowing from the coal body 4, and the liquid sewage treatment subsystem is connected to the bottom of the experimental box to treat the liquid flowing out from the coal body 4.

[0040] Preferably, the experimental box is provided with an insulating interlayer around it. The function of the insulating interlayer is to prevent heat loss during the coal spontaneous combustion experiment and maintain the heat storage conditions required for the coal spontaneous combustion. The insulating interlayer is filled with insulating or heat-insulating materials. The insulating or heat-insulating materials in this embodiment are water 3. Of course, other types of insulating or heat-insulating materials can also be used, such as insulation cotton, insulation board, foam insulation agent, etc. The insulating interlayer of the experimental box is provided with an electric heating wire 38 for heating. The electric heating wire 38 is in the water 3 of the insulating interlayer to maintain the constant temperature of the water 3, prevent the temperature of the coal body 4 from exchanging heat with the water temperature, and keep the coal body 4 at the required experimental temperature.

[0041] In one embodiment, a bottom pipeline 33 located at the bottom of the coal body 4 is buried in the experimental box, and a plurality of holes are provided on the bottom pipeline 33 in the shape of a sieve hole. The bottom pipeline 33 is connected to a connecting pipe 37 extending through the bottom plate of the experimental box. The fire extinguishing agent source is used to provide gaseous fire extinguishing agent, and the nitrogen and oxygen provided by the nitrogen source 18 and the oxygen source 17 respectively are input into the experimental box through the connecting pipe 37, and the liquid in the experimental box flows out to the liquid sewage treatment subsystem through the connecting pipe 37.

[0042] The fire monitoring system also includes a gas mixing box 15, the output end of the gas mixing box 15 is connected to the connecting pipe 37 through a gas supply pipeline, and the nitrogen source 18 and the oxygen source 17 are connected to the input end of the gas mixing box 15 through a nitrogen branch pipe 19 and an oxygen branch pipe 20 respectively; the nitrogen branch pipe 19 is provided with a nitrogen decompression valve 11 and a nitrogen flowmeter 13, and the oxygen branch pipe 20 is provided with an oxygen decompression valve and an oxygen flowmeter 14. The gas mixing box 15 is also provided with a spiral blade 16 for stirring and mixing nitrogen and oxygen. The gas mixing box 15 is used to stir and mix nitrogen and oxygen through the spiral blade 16 and then introduce them into the coal body 4, which is more in line with the gas composition infiltrated into the real coal seam.

[0043] The fire extinguishing simulation system further comprises a fire extinguishing agent mixing box 23, the input end of the fire extinguishing agent mixing box 23 is connected to the fire extinguishing agent source, the output end of the fire extinguishing agent mixing box 23 is connected to a fire extinguishing agent output main pipe 30, the fire extinguishing agent mixing box 23 is used to form a mixed fire extinguishing agent 22 with the fire extinguishing agent material input from the fire extinguishing agent source before outputting it, the output end of the fire extinguishing agent output main pipe 30 is connected to a gas fire extinguishing agent output branch pipe and a solid-liquid fire extinguishing agent output branch pipe through a branch, the gas fire extinguishing agent output branch pipe is connected to the The connecting pipe 37 is connected, and the solid-liquid fire extinguishing agent output branch is connected to the top of the experimental box; there are two fire extinguishing agent sources, namely a gas fire extinguishing agent source 24 for providing gas fire extinguishing agent, and a solid-liquid fire extinguishing agent source 25 for providing solid or liquid fire extinguishing agent; the fire extinguishing agent output main pipe 30 is provided with a pressure pump 21 and a fire extinguishing agent flow meter 12, and the gas fire extinguishing agent output branch and the solid-liquid fire extinguishing agent output branch are respectively connected to a gas fire extinguishing agent flow valve 9 and a solid-liquid fire extinguishing agent flow valve 10.

[0044] The liquid sewage treatment subsystem includes a liquid recovery device 35, which is connected to the connecting pipe 37. A pressure valve 36 is provided in the pipeline between the connecting pipe 37 and the liquid recovery device 35. The liquid recovery device 35 is also connected to the fire extinguishing agent mixing tank 23. A valve 34 is provided in the pipeline between the liquid recovery device 35 and the fire extinguishing agent mixing tank 23.

[0045] The gas waste treatment subsystem includes a waste gas treatment bottle 29, the waste gas pipeline 32 of the waste gas treatment bottle 29 is connected to the top of the experimental box, and a waste gas flow valve 7 is provided in the waste gas pipeline 32. The waste gas treatment bottle 29 is used to collect waste for reuse in experiments, recycling and saving materials.

[0046] In this embodiment, the solid-liquid fire extinguishing agent source 25 and the gaseous fire extinguishing agent source 24 are mainly filled with fire extinguishing materials such as liquid nitrogen, colloid, foam, grouting, gel, other inert gases, microorganisms, and new composite materials. The fire extinguishing materials in the fire extinguishing agent mixing box 23 all come from the solid-liquid fire extinguishing agent source 25 or the gaseous fire extinguishing agent source 24. In actual use, they are selected according to needs. When the fire extinguishing agent materials are to be tested, these substances can be pre-mixed in the fire extinguishing agent mixing box 23. When testing a single fire extinguishing material, the fire extinguishing agent mixing box 23 can be removed or not. Among them, the solid or liquid fire extinguishing agent is transported to the top of the experimental box along the pipeline through the pressure pump 21, the fire extinguishing agent flow meter 12 and the solid-liquid fire extinguishing agent flow valve 10 for fire extinguishing, and then flows to the liquid recovery device 35 through the bottom pipeline 33 with an orifice, the connecting pipe 37 and the exhaust gas flow valve 7 for treatment. After the treatment is completed, it flows to the fire extinguishing agent mixing box 23 through the pipeline with a valve 34. The recovered fire extinguishing agent can be re-input into the coal body 4 for secondary fire extinguishing, which can save fire extinguishing agent materials.

[0047] The present invention also provides an experimental method for an experimental device simulating the spontaneous combustion and extinction process of coal in a closed fire zone, comprising the following steps:

[0048] 1) Fill the experimental box with coal samples to form a coal body 4, and disperse and bury multiple thermocouples 1 and multiple gas inlets 2 in the coal body 4, and seal the experimental box, and then connect the fire monitoring system, the fire extinguishing simulation system and the sewage treatment system to the coal body 4 simulation system respectively and ensure the sealing of the connection;

[0049] 2) Start the fire monitoring system, the nitrogen source 18 and the oxygen source 17 respectively provide nitrogen and oxygen to form a mixed gas and pass it into the coal body 4 from the bottom of the experimental box, collect the gas discharged from the gas inlet 2 in real time by the chromatograph 28 and monitor the temperature in the coal body 4 in real time by the thermocouple 1, and comprehensively judge the degree of spontaneous combustion of the coal body 4;

[0050] 3) When it is determined that the coal body 4 spontaneously ignites and reaches the preset fire extinguishing conditions, the fire extinguishing simulation system is started, and the fire extinguishing agent source provides gaseous fire extinguishing agent and passes it into the coal body 4 from the bottom of the experimental box, or provides solid fire extinguishing agent or liquid fire extinguishing agent and passes it into the coal body 4 from the top of the experimental box until the fire is extinguished; wherein,

[0051] When executing steps 2) and 3, the gas overflowing from the coal body 4 is treated by the gas sewage treatment subsystem of the sewage treatment system, and at the same time, the liquid sewage treatment subsystem of the sewage treatment system treats the liquid flowing out from the coal body 4.

[0052] It should be noted here that the fire condition of the coal body 4 can be comprehensively judged based on the real-time collection of gas discharged from the gas intake port 2 by the chromatograph 28 and the real-time monitoring of the temperature in the coal body 4 by the thermocouple 1, so as to know the real-time situation of the fire being extinguished. When the fire is not extinguished, the fire extinguishing agent source continues to provide gaseous fire extinguishing agent and pass it into the coal body 4 from the bottom of the experimental box, or provides solid fire extinguishing agent or liquid fire extinguishing agent and passes it into the coal body 4 from the top of the experimental box until the fire is extinguished.

[0053] The present invention comprehensively judges the degree of spontaneous combustion of the coal body 4 by using the temperature of the coal body 4, the oxygen absorption rate of the coal, and index gases (such as CO, CH4, ethylene, etc.). When olefin gases (generally ethylene) are detected, it means that the spontaneous combustion process of the coal has entered the accelerated oxidation stage. When acetylene gases appear, it means that the spontaneous combustion of the coal has entered the intense oxidation stage, which are respectively used as the judgment basis of the present invention.

[0054] Preferably, after a fire is extinguished using a solid fire extinguishing agent or a liquid fire extinguishing agent, the liquid waste treatment subsystem recovers the liquid containing the fire extinguishing agent and then delivers it to the fire extinguishing simulation system so that the fire extinguishing simulation system can reuse the recovered fire extinguishing agent.

[0055] The following experiments can be performed by using the experimental device and experimental method for simulating the spontaneous combustion and extinction process of coal in a closed fire zone of the present invention:

[0056] (1) Coal spontaneous combustion experiment:

[0057] By loading the coal sample to be tested, checking the air tightness of the device, and then introducing air (nitrogen + oxygen) atmosphere into the device, using a flow meter to monitor the flow rate of the atmosphere, and monitoring the changes in parameters such as temperature and gas products in the coal body over time during the heating process until the coal in the box spontaneously ignites.

[0058] (2) Experiment on inhibitors to inhibit coal spontaneous combustion

[0059] By loading the coal sample to be tested, injecting the inhibitor into the coal body during the low-temperature oxidation stage of the coal, monitoring the gas products and other parameters of the coal body during the oxidation process after the injection of the inhibitor, until the coal sample spontaneously ignites. This experiment can determine whether the added inhibitor prolongs the natural ignition period of the coal.

[0060] Although specific embodiments of the present invention are described above, those skilled in the art should understand that these are merely examples and that various changes or modifications may be made to the embodiments without departing from the principles and essence of the present invention. The scope of protection of the present invention is limited only by the appended claims.

Claims

1. An experimental device for simulating the spontaneous combustion and extinction process of coal in a closed fire area, characterized in that: It includes coal simulation system, fire monitoring system, fire extinguishing simulation system and sewage treatment system, among which: The coal simulation system comprises an experimental box which is sealed inside and filled with coal; The fire monitoring system includes a chromatograph, a nitrogen source, an oxygen source, and a plurality of thermocouples and gas outlets embedded in the coal body and distributed at different positions. The sampling tube of the chromatograph is connected to a gas collecting bottle, and the gas collecting bottle is connected to the gas outlet through a gas sampling tube. The nitrogen source and the oxygen source provide nitrogen and oxygen respectively and are introduced into the coal body from the bottom of the experimental box. The fire extinguishing simulation system includes a fire extinguishing agent source, which is used to provide a gaseous fire extinguishing agent and pass it into the coal body from the bottom of the experimental box, or to provide a solid fire extinguishing agent or a liquid fire extinguishing agent and pass it into the coal body from the top of the experimental box; The sewage treatment system includes a gas sewage treatment subsystem and a liquid sewage treatment subsystem. The gas sewage treatment subsystem is connected to the top of the experimental box to treat the gas overflowing from the coal body, and the liquid sewage treatment subsystem is connected to the bottom of the experimental box to treat the liquid flowing out from the coal body. A bottom pipeline located at the bottom of the coal body is buried in the experimental box, and a plurality of holes are provided on the bottom pipeline in the shape of a sieve hole. The bottom pipeline is connected to a connecting pipe extending through the bottom plate of the experimental box. The gaseous fire extinguishing agent provided by the fire extinguishing agent source, and the nitrogen and oxygen provided by the nitrogen source and the oxygen source respectively are input into the experimental box through the connecting pipe, and the liquid in the experimental box flows out to the liquid sewage treatment subsystem through the connecting pipe; The fire extinguishing simulation system also includes a fire extinguishing agent mixing box, the input end of the fire extinguishing agent mixing box is connected to the fire extinguishing agent source, the output end of the fire extinguishing agent mixing box is connected to a fire extinguishing agent output main pipe, the output end of the fire extinguishing agent output main pipe is connected to a gas fire extinguishing agent output branch pipe and a solid-liquid fire extinguishing agent output branch pipe through a branch, the gas fire extinguishing agent output branch pipe is connected to the connecting pipe, and the solid-liquid fire extinguishing agent output branch pipe is connected to the top of the experimental box body; there are two fire extinguishing agent sources, namely a gas fire extinguishing agent source for providing gas fire extinguishing agent, and a solid-liquid fire extinguishing agent source for providing solid or liquid fire extinguishing agent; a pressure pump and a fire extinguishing agent flow meter are provided on the fire extinguishing agent output main pipe, and the gas fire extinguishing agent output branch pipe and the solid-liquid fire extinguishing agent output branch pipe are respectively connected to a gas fire extinguishing agent flow valve and a solid-liquid fire extinguishing agent flow valve; The liquid sewage treatment subsystem includes a liquid recovery device, which is connected to the connecting pipe, and a pressure valve is provided in the pipeline between the connecting pipe and the liquid recovery device. The liquid recovery device is also connected to the fire extinguishing agent mixing box, and a valve is provided in the pipeline between the liquid recovery device and the fire extinguishing agent mixing box.

2. The experimental device for simulating the spontaneous combustion and extinction process of coal in a closed fire zone according to claim 1, characterized in that: The experimental box is a rectangular structure with a detachable sealing cover connected to the top, and a mesh is provided between the sealing cover and the top of the coal body; the thermocouples and the gas intake ports are inserted into the coal body after penetrating the side walls of the experimental box, and each side wall corresponds to at least two thermocouples and at least two gas intake ports; the gas production pipe is connected to a gas production flow valve and a gas production flow meter.

3. The experimental device for simulating the spontaneous combustion and extinction process of coal in a closed fire zone according to claim 1, characterized in that: A heat-insulating interlayer is arranged around the experimental box, the heat-insulating interlayer is filled with heat-insulating or thermal-preserving materials, and an electric heating wire is also arranged in the heat-insulating interlayer.

4. The experimental device for simulating the spontaneous combustion and extinction process of coal in a closed fire zone according to claim 1, characterized in that: The fire monitoring system also includes a gas mixing box, the output end of the gas mixing box is connected to the connecting pipe through a gas supply pipeline, and the nitrogen source and the oxygen source are connected to the input end of the gas mixing box through a nitrogen branch pipe and an oxygen branch pipe respectively; a nitrogen decompression valve and a nitrogen flow meter are provided on the nitrogen branch pipe, and an oxygen decompression valve and an oxygen flow meter are provided on the oxygen branch pipe. A spiral blade for stirring and mixing nitrogen and oxygen is also provided in the gas mixing box.

5. The experimental device for simulating the spontaneous combustion and extinction process of coal in a closed fire zone according to claim 1, characterized in that: The gas wastewater treatment subsystem comprises a waste gas treatment bottle, a waste gas pipeline of the waste gas treatment bottle is connected to the top of the experimental box, and a waste gas flow valve is arranged in the waste gas pipeline.

6. An experimental method for the experimental device for simulating the spontaneous combustion and extinction process of coal in a closed fire zone according to any one of claims 1 to 5, characterized in that: The following steps are involved: 1) Fill the experimental box with coal samples to form a coal body, and evenly bury multiple thermocouples and multiple gas inlets in the coal body, seal the experimental box, and then connect the fire monitoring system, fire extinguishing simulation system and sewage treatment system to the coal body simulation system respectively and ensure the sealing of the connection; 2) Start the fire monitoring system, provide nitrogen and oxygen from the nitrogen source and oxygen source respectively to form a mixed gas and pass it into the coal body from the bottom of the experimental box, collect the gas discharged from the gas inlet in real time by the chromatograph and monitor the temperature in the coal body in real time by the thermocouple, and comprehensively judge the degree of spontaneous combustion of the coal body; 3) When it is determined that the coal body is ignited spontaneously and reaches the preset fire extinguishing conditions, the fire extinguishing simulation system is started, and the fire extinguishing agent source provides gaseous fire extinguishing agent and passes it into the coal body from the bottom of the experimental box, or provides solid fire extinguishing agent or liquid fire extinguishing agent and passes it into the coal body from the top of the experimental box until the fire is extinguished; When executing steps 2) and 3, the gas overflowing from the coal body is treated by the gas discharge treatment subsystem of the discharge treatment system, and at the same time, the liquid discharge treatment subsystem of the discharge treatment system treats the liquid flowing out from the coal body.

7. The experimental method according to claim 6, characterized in that: After a fire is extinguished using a solid or liquid fire extinguishing agent, the liquid sewage treatment subsystem recovers the liquid containing the fire extinguishing agent and then delivers it to the fire extinguishing simulation system so that the fire extinguishing simulation system can reuse the recovered fire extinguishing agent.

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