WO2021253280A1 - 一种模拟采空区自然发火的试验方法 - Google Patents

一种模拟采空区自然发火的试验方法 Download PDF

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WO2021253280A1
WO2021253280A1 PCT/CN2020/096554 CN2020096554W WO2021253280A1 WO 2021253280 A1 WO2021253280 A1 WO 2021253280A1 CN 2020096554 W CN2020096554 W CN 2020096554W WO 2021253280 A1 WO2021253280 A1 WO 2021253280A1
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coal
goaf
gas
spontaneous combustion
similar material
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PCT/CN2020/096554
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English (en)
French (fr)
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谢军
辛林
程卫民
付海政
王刚
宋玥
刘震
刘晨
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山东科技大学
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Priority to PCT/CN2020/096554 priority Critical patent/WO2021253280A1/zh
Publication of WO2021253280A1 publication Critical patent/WO2021253280A1/zh

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D21/00—Measuring or testing not otherwise provided for
    • G01D21/02—Measuring two or more variables by means not covered by a single other subclass
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N31/00—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods
    • G01N31/12—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods using combustion
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/22—Fuels; Explosives

Definitions

  • the invention belongs to the field of mining engineering and relates to a test method for simulating spontaneous combustion in a goaf.
  • the invention patent mainly solves how to simulate the occurrence of coal and rock, the air leakage conditions in the goaf, the natural collapse of the coal roof and the natural distribution of the remaining coal, and the experiment under different coal types, ventilation flow, oxygen concentration, coal thickness and other conditions
  • Coal spontaneous combustion process in the goaf study the shortest spontaneous combustion period of coal and the critical value of various indicators, monitor the temperature and gas composition changes in the spontaneous combustion process, the oxidation and heat release of coal, the influence factors of coal spontaneous combustion and the influence of coal spontaneous combustion process Some other characteristic parameters are studied, and indicators for judging the process of coal spontaneous combustion are put forward to study the mechanism of coal spontaneous combustion, so as to realize early prediction of coal spontaneous combustion. Therefore, the patent of the present invention designs a set of similar simulation experimental devices and methods for the whole process of coal spontaneous combustion, which meets the experimental requirements for the determination of the shortest spontaneous combustion period of coal, gas analysis and the study of the characteristics of coal and rock temperature change law.
  • coal spontaneous combustion is an extremely complex, dynamically changing, and automatically accelerated physical and chemical process.
  • coal is an inhomogeneous body with extremely complex physical structure and chemical mineral composition.
  • the molecular structure model is still inconclusive, and it is difficult to clarify the occurrence and development of coal spontaneous combustion theoretically.
  • the physical model test is to put the actual occurrence and conditions of the site in the laboratory according to a certain similarity ratio, based on the similarity theory, and meet the basic similar conditions (including geometric, kinematic, thermal, dynamic and single-valued conditions are similar), It is a test method used to simulate the main characteristics of the real process by pushing back to the prototype through the rules between certain parameters obtained in the model test, so as to obtain an understanding of the regularity of the prototype.
  • physical model tests have been widely used in the study of various safety issues in the process of coal mining due to their intuitiveness and ease of measurement.
  • coal spontaneous combustion is an extremely complex and dynamic physical and chemical process, and its essence is a process that slowly oxidizes, automatically releases heat and raises temperature and finally causes combustion.
  • Gas migration and gas composition changes in the goaf are affected by the combined effects of stope air distribution, air leakage from connected roadways and stope geological conditions. Air leakage in the goaf is also the main cause of spontaneous fires in the goaf.
  • coal spontaneous combustion simulation experimental device to have a large enough size to meet the simulation of its geological conditions, air leakage conditions, floating coal distribution conditions and other factors, so as to provide a better understanding of the coal spontaneous combustion mechanism and coal
  • the research on spontaneous combustion forecasting technology creates conditions.
  • the existing coal spontaneous combustion experiment device cannot effectively simulate the geological conditions of the goaf and the air leakage conditions in the goaf.
  • the Chinese patent with Publication No. CN 107247127 A "Model Test Platform and Test Method for Spontaneous Combustion in Goaf Considering Atmospheric Pressure” includes positive pressure fans, thermocouples, test boxes, air humidifiers, and air heating. Air filter, air inlet pipe, air outlet pipe, etc. This technical solution is carried out in the test box.
  • the experimental space is narrow, and it cannot simulate the occurrence of coal seam overburden in the goaf, cannot effectively simulate the air leakage conditions of the air distribution roadway in the stope, and cannot effectively simulate the collapse of the goaf and the loss of coal. Distribution status.
  • the existing goaf coal spontaneous combustion simulation experimental device cannot simulate the collapse of the leftover coal in the goaf and the collapse of the roof of the goaf, so it cannot simulate the occurrence of the leftover coal in the goaf and the roof and floor more realistically
  • the state includes the loose and broken state of the leftover coal, the compaction of the leftover coal in the goaf, the fissure channels around the goaf, and the air leakage status.
  • the purpose of the present invention is to provide a test method for simulating the spontaneous combustion in the goaf.
  • the beneficial effect of the present invention is to accurately and effectively simulate the whole process of the spontaneous combustion of coal in the goaf in the laboratory under the condition of air leakage, and to simulate the large spatial scale.
  • the gas is obtained by the gas chromatograph and analyzed by gas chromatograph to obtain the gas composition and concentration distribution and evolution law of different positions; analyze the composition, concentration and the change rule of the index gas during the spontaneous combustion process of the coal remnant in the goaf, and obtain the goaf Spontaneous combustion period of leftover coal. So as to create good experimental conditions for the study of the mechanism of coal spontaneous combustion in the goaf and the division of the three zones of spontaneous combustion in the goaf.
  • the technical scheme adopted by the experimental device for simulating spontaneous combustion in the goaf includes an experimental furnace body.
  • the experimental furnace body is divided into the outer layer of the furnace steel plate, ordinary brick layer, polyurethane insulation layer, water interlayer, and refractory brick layer from the outside to the inside.
  • the experimental furnace body is equipped with a coal outlet, an air inlet pipe and a return air pipe.
  • the upper part of the experimental furnace body is equipped with a roof; the experimental furnace body is equipped with a coal seam, and a similar material bottom plate and a preset water bag are arranged under the coal seam.
  • the bag Above the bag is equipped with a bottom plate of similar material to be sinked, above the coal seam is equipped with a first similar material top plate and a second similar material top plate, above the second similar material top plate is equipped with a multi-point thermocouple measuring rod and a gas beam tube, multi-point thermoelectric There is an overburden between the coupling rods, the multi-point thermocouple rod is equipped with several thermocouples, and the multi-point thermocouple rod and the gas beam tube are in close contact with similar materials; the coal mining face on the coal seam is equipped with two ends In the air inlet and return lanes, arched hollow protective pipes are laid on the air inlet lane, coal mining face and return air lane to support the coal body to form a certain passage space to construct the air inlet and return system of the goaf and working face , The air inlet lane is connected with the air inlet pipe on the experimental furnace, and the return air lane is connected with the return air pipe on the experimental furnace.
  • air inlet pipe is sequentially connected to the vortex flowmeter, gas temperature measuring thermocouple, gas pressure gauge, heat exchanger, and blower outside the experimental furnace body, and the heat exchanger is connected to the heat exchanger control cabinet.
  • the return air pipe is connected to the vortex flowmeter, gas temperature measuring thermocouple, gas pressure gauge, gas chromatograph, and gas collector outside the experimental furnace body in sequence;
  • the coal outlet is connected to the gas collector and the data collection module;
  • data The acquisition module and the gas chromatograph are connected to an industrial computer.
  • Another experimental method of the present invention for simulating spontaneous combustion in the goaf is carried out according to the following steps:
  • Step 1 Selection of similar materials; using river sand as aggregates, clay and gypsum as cements, using orthogonal test and comprehensive experimental methods to analyze the uniaxial compressive strength under different material ratios, and calculating with similar principles
  • the compressive strength is compared to determine the ratio of river sand and clay in different roof and floor rock layers that meet the similar ratio; collect the required coal at the work site, as the experimental coal, and choose loess as the overburden, according to 1/10 of the actual thickness of the site
  • the geometric scaling ratio of ⁇ 1/30 determines the thickness of similar materials for the coal seam and the roof and floor, and paves similar materials for the coal seam and the roof and floor based on the ratio of similar materials;
  • Step 2 Simulate the construction of the goaf system; construct the air intake lane, return airway and coal mining face of the goaf area and working face by laying arched hollow protective pipes;
  • the working face, return airway and return air pipe constitute the air inlet and return air system that simulates the goaf and working face system.
  • the air inlet lane, coal mining face and return airway are all constructed by arched hollow protection pipes to simulate the air inlet lane. And work facing the air leakage in the goaf;
  • Step 3 layout of temperature measurement and gas extraction; while laying the goaf coal seam and the first similar material coal roof, the second similar material coal roof and overburden, at the same time bury multi-point thermocouple measuring rods and gas extraction at corresponding locations
  • the beam tube, the measuring rod and the gas beam tube are in close contact with the first similar material coal seam roof, the second similar material coal seam roof and the covering layer, and the gas beam tube air inlet is protected from dust;
  • thermocouple measuring points There are a total of multiple thermocouple measuring points arranged from bottom to top in the height direction of multi-point thermocouple measuring rods, which can monitor the temperature values at different heights from the bottom to the top of the goaf.
  • the thermocouple measuring rods are arranged in a grid pattern and can be monitored. The temperature value in the three-dimensional space of the whole goaf;
  • the gas-taking beam pipes are distributed in a grid within the scope of the goaf, and the gas-taking pipes at each position take gas from multiple positions in the height direction of the goaf, so as to analyze the gas in the three-dimensional space of the goaf.
  • Step 4 Lay similar simulation materials and goaf system; lay the bottom plate of similar material, coal seam, top plate of first similar material, top plate of second similar material and surface covering layer from bottom to top in the experimental furnace body, and press while laying.
  • Real treatment, after cementation, it will have a certain strength, and meet the requirements of similar strength ratio of the roof and floor rocks in the mined-out area;
  • a water bag of a certain height is preset in the goaf area in advance.
  • the height of the water bag is equal to the simulated mining height.
  • the coal seam mining height area is pre-filled with similar materials for the floor, and the goaf area is above it. Coal seam remnants;
  • Step 5 simulation of the collapse process of the top coal in the goaf; when the similar simulation materials and the goaf system are laid, the water in the water bag is pumped out of a certain volume of water, so that the height of the water discharged from the water bag is equal to that of coal seam mining.
  • the bottom of the water bag and similar materials to be sinking moves downwards and fills the height of the water released from the water bag.
  • This method causes the collapse of the remaining coal on the top of the goaf, and the top coal in the goaf naturally collapses and covers the mining area.
  • the floor of the goaf can simulate the accumulation and distribution of the leftover coal in the goaf. At the same time, it can also simulate the falling and bending of the overlying rock above the leftover coal, creating pores and cracks, forming an upper three-zone structure;
  • Step 6 the simulation of the natural combustion process of the coal in the goaf; the remaining coal in the goaf accumulates in the goaf. Due to the leakage of the air intake road and the coal working face, the remaining coal in the goaf is in contact with oxygen. Under the action of physical adsorption, chemical adsorption and oxidation reaction, tiny heat is generated, and under certain conditions, the heat production rate of oxidation is greater than the heat dissipation rate to the environment. The heat accumulation makes the temperature of coal body rise slowly and continuously. After the critical self-heating temperature, the oxidation heating rate is accelerated, and finally reaches the ignition point temperature of coal and burns, achieving the purpose of simulating the spontaneous combustion process of coal;
  • the inlet air parameters are monitored by the gas temperature measuring thermocouple, gas pressure gauge, and vortex flowmeter equipment arranged on the air inlet pipeline;
  • the return air parameters are monitored by the gas temperature measuring thermocouple, the gas temperature measuring thermocouple and the vortex flowmeter arranged on the return air pipeline.
  • Gas pressure gauge, vortex flowmeter, gas chromatograph equipment monitoring the temperature value of the monitoring point in the goaf is monitored by the thermocouple in the multi-point thermocouple rod arranged in the goaf; the gas at the monitoring point in the goaf The components and concentration values are monitored by the gas extraction tube and gas chromatograph equipment arranged in the goaf; all monitoring data is collected by the data acquisition module and sent to the industrial computer, and the data is recorded and analyzed by the relevant monitoring software And storage.
  • the purpose of the present invention is to more realistically simulate the roof and floor storage conditions of the leftover coal in the goaf from a larger spatial scale; by simulating the roof coal and the collapse process of the roof after the goaf is mined, the mining is more realistically simulated.
  • the existing state of the roof and floor of the leftover coal in the goaf including the loose and broken state of the leftover coal, the compaction of the leftover coal in the goaf, the fissure channels around the goaf, and the air leakage.
  • the beneficial effect of the present invention is that it can accurately and effectively simulate the whole process of coal spontaneous combustion in the goaf under the condition of air leakage in the laboratory, simulate the occurrence of coal and rock in the goaf in a large spatial scale, and the natural top coal and roof of the goaf.
  • the distribution status of caving and remaining coal is monitored, and the temperature field distribution and evolution law within the scope of the mined-out area are monitored; at the same time, gas can be extracted from different positions of the mined-out area by distributed beam tubes, and the gas components and gas components at different positions can be obtained by gas chromatograph analysis.
  • Concentration distribution and evolution law analyze the composition and concentration of the index gas in the spontaneous combustion process of the goaf coal and its change with time, and get the spontaneous combustion period of the goaf coal. So as to create good experimental conditions for the study of the mechanism of coal spontaneous combustion in the goaf and the division of the three zones of spontaneous combustion in the goaf.
  • Figure 1 is a side sectional view of a simulation experiment device for coal spontaneous combustion in a goaf
  • Figure 2 is a schematic diagram of the leftover coal and the water bag after the drainage of the coal spontaneous combustion simulation experiment device in the goaf;
  • Figure 3 is a top view of a simulation experiment device for coal spontaneous combustion in a goaf
  • Fig. 4 is a schematic diagram of the experimental method for simulating spontaneous combustion in the goaf of the present invention.
  • the experimental furnace part it mainly consists of five parts: the experimental furnace part, the similar material part of the goaf, the air supply and exhaust part, the gas collection and analysis part, the automatic temperature measurement and monitoring system.
  • the experimental furnace body is shown in Fig. 1 to Fig. 3, including: outer furnace steel plate 1, ordinary brick layer 2, polyurethane heat insulation layer 3, water interlayer 4, refractory brick layer 5, air inlet pipe 19, return air pipe 20.
  • the experimental furnace body of the present invention is a cylinder as a whole, the outer diameter of the experimental furnace is 3.73m, the inner diameter of the experimental furnace body is 2.8m, and the net height of the experimental furnace body is 2.5m.
  • the similar material part of the goaf includes: coal seam 8 and leftover coal 801, similar material bottom plate 9, preset water bag 10, similar material bottom plate 11 to be sinked, first similar material top plate 12 and second similar material top plate 13, covering layer 14. Simulated coal mining face 21, arched hollow protection pipe 18, air inlet lane 32, and air return lane 33.
  • the scope of the mined-out area is 1.4m ⁇ 1.4m, and the height of the mined-out area is the same as the height of the laid coal seam.
  • the air supply and exhaust parts include: blower 22, heat exchanger 23, heat exchanger control cabinet 24, gas pressure gauge 25, gas temperature measuring thermocouple 26, and vortex flowmeter 27.
  • the gas collection and analysis part includes: gas collection tube 17, gas collector 29, gas chromatograph 30.
  • the part of the automatic temperature measurement and monitoring system includes: a multi-point thermocouple measuring rod 15, a thermocouple 16, a data acquisition module 28, and an industrial computer 31.
  • the experimental method for simulating spontaneous combustion in the goaf of the present invention includes the following steps:
  • Step 2 Simulate the construction of the goaf system.
  • the air intake lane 32, the return air lane 33 and the coal mining face 21 of the gob area and the working face are constructed by laying the arched hollow protective pipe 18.
  • the experimental furnace air inlet pipe 19, air inlet lane 32, coal mining face 21, return air lane 33, and air return pipe 20 constitute an air inlet and return system that simulates the goaf and working face system.
  • the air inlet lane 32, Both the coal mining face 21 and the return air lane 33 are constructed by arched hollow protective pipes 18, which can simulate the air leakage from the air inlet lane 32 and the working face 21 to the goaf.
  • Step 3 Temperature measurement and gas extraction arrangement.
  • thermocouple measuring rods 15 and gas-taking pipes 17 are buried at corresponding positions, and measuring rods 15 and gas-taking pipes 17 are Similar materials are in close contact, and the air intake of the air beam tube 17 is protected against dust.
  • the multi-point thermocouple measuring rod 15 has a plurality of thermocouple 16 measuring points arranged from bottom to top in the height direction, and the temperature values from the bottom to the top of the goaf can be monitored at different heights.
  • the thermocouple measuring rods 15 are arranged in a grid, and the temperature value of the three-dimensional space of the whole goaf can be monitored.
  • the gas extraction tube 17 is distributed in a grid within the scope of the goaf, and the gas extraction tube 17 at each position can extract gas from multiple positions in the height direction of the goaf, so as to analyze and obtain the gas extraction.
  • Step 4 the laying of similar simulation materials and goaf system.
  • a water bag 10 of a certain height is preset in the goaf area in advance, and the height of the water bag 10 should be equal to the simulated mining height.
  • the floor similar material 11 is pre-filled in the mining height range of the coal seam, and the remaining coal 801 of the goaf coal seam is on it.
  • the air inlet lane 32 is connected with the air inlet pipe 19 on the experimental furnace, and the return air lane 33 is connected with the return air pipe 20 on the experimental furnace.
  • Step 5 Simulation of the collapse process of the top coal in the goaf.
  • the water in the water bag 10 is pumped out of a certain volume of water, so that the height of the water discharged from the water bag 10 is equal to the height of the coal seam. 10 and the bottom plate 11 of similar material to be sinked on it moves downward and fills the water bag 10 to release the water height.
  • the remaining coal 801 at the top of the goaf may collapse, and the overburden 12 may collapse and move.
  • the top coal in the goaf naturally collapses and covers the floor of the goaf, simulating the accumulation and distribution of the leftover coal 801 in the goaf.
  • it can also simulate the straddling and bending of the overlying rock above the leftover coal, creating pores and cracks, and forming " "Upper three belts" structure.
  • Step 6 the simulation of the spontaneous combustion process of coal in the goaf.
  • the leftover coal 801 in the goaf accumulates in the goaf. Due to the air leakage of the air intake lane 32 and the coal mining face 21, the leftover coal 801 in the goaf comes into contact with oxygen, and the physical adsorption, chemical adsorption and oxidation reaction of the coal oxygen Under certain conditions, a small amount of heat is generated, and under certain conditions, the heat generation rate of oxidation is greater than the rate of heat dissipation to the environment. The heat accumulation causes the temperature of the coal body to rise slowly and continuously. When the critical self-heating temperature of the coal is reached, the oxidation temperature rise rate Speed up, and finally reach the ignition point temperature of coal and burn, which is called the spontaneous combustion of coal (or coal spontaneous combustion) process.
  • the spontaneous combustion of coal is the result of the contradiction between the heat production of coal and the heat dissipation to the environment. Therefore, as long as the factors related to the heat production of coal spontaneous combustion and the heat dissipation to the environment can affect the spontaneous combustion process of coal. It can be divided into internal factors and external factors.
  • coalification degree coal moisture, coal rock composition, coal sulfur content, coal particle size and pore structure, coal gas content
  • its external factors include coal seam geological occurrence conditions (coal seam thickness, inclination, burial Depth, geological structure and surrounding rock properties), mining technology factors (stopping speed, mining period, the amount of coal lost in the goaf and its concentration, roof management methods, coal pillars and their destruction, and difficulty in closing the goaf Etc.), ventilation management factors (air leakage in the goaf).
  • the experimental device for simulating the spontaneous combustion of the goaf of the present invention can not only simulate the process of coal spontaneous combustion in the goaf under a certain specific condition, but also can adopt the method of controlled variables to control the one that affects the spontaneous combustion of coal. Or multiple factors to carry out experimental research.
  • the sub-steps of simulation of the coal spontaneous combustion process in the goaf under a certain condition in the above step 6 include: according to the actual situation of the goaf on site, including the above internal and external factors, similar theories are simulated at the laboratory scale Goaf coal spontaneous combustion process, get the goaf spontaneous combustion period; goaf spontaneous combustion high temperature zone range and expansion law, including ignition point (fire source) location, range, ignition intensity, temperature field distribution research; goaf spontaneous combustion Index gas concentration, composition, distribution and expansion law; "three zones” (non-spontaneous combustion zone, spontaneous combustion zone and suffocation zone) distribution range of the goaf area, etc.
  • the sub-step of using the controlled variable method to carry out experimental research on one or more factors affecting coal spontaneous combustion in the above step 6 includes: selecting one or more of the above internal factors and external factors, and through the numerical changes of the factors, Study the influence of this factor on the spontaneous combustion process of coal, and analyze the influence of the change of this factor on the main characteristics of coal spontaneous combustion (such as spontaneous combustion period, temperature field, concentration field distribution, index gas change rule, etc.), spontaneous combustion period and goaf law.
  • Step 7 Data monitoring and analysis.
  • the main monitoring data in the experiment process of the present invention are: inlet air parameters (temperature, pressure, flow), return air parameters (temperature, pressure, flow, gas composition), temperature value of the goaf monitoring point, and goaf Monitoring point gas composition and concentration value.
  • the inlet air parameters are monitored by gas temperature measuring thermocouple 26, gas pressure gauge 25, vortex flowmeter 27 and other equipment arranged on the air inlet pipeline; the return air parameters are monitored by the gas temperature measuring thermoelectric device arranged on the return air pipeline. Couple 26, gas pressure gauge 25, vortex flow meter 27, gas chromatograph 30 and other equipment monitoring; the temperature value of the monitoring point in the goaf is determined by the thermocouple in the multi-point thermocouple rod 15 arranged in the goaf 16 Monitoring; The gas composition and concentration values at the monitoring points of the mined-out area are monitored by equipment such as the gas bundle pipe 17 and the gas chromatograph 30 arranged in the mined-out area.
  • All monitoring data is collected by the data collection module 28 and sent to the industrial computer 31, and the data is recorded, analyzed and stored by the relevant monitoring software.
  • the existing coal spontaneous combustion simulation experiment device in the goaf is small in size, so it is difficult to more realistically simulate the spontaneous combustion process of the coal spontaneous combustion in the goaf on a larger spatial scale.
  • the experimental device of the present invention has an inner diameter of 2.8m, an inner height of 2.5m, and a simulated goaf area of 1.4m ⁇ 1.4m.
  • the existing goaf coal spontaneous combustion simulation experiment device cannot be laid with similar materials on the roof and floor of the coal seam, or the paved height is limited, so it is impossible to more realistically simulate the roof and floor storage conditions of the leftover coal in the goaf.
  • the experimental furnace body of the present invention is a cylinder as a whole, with an inner clear height of 2.5m, which means that multiple layers of similar material bottom plates, coal seams and similar material roof plates can be laid.
  • the total height can reach 2.8m, and the inner diameter of the experimental furnace is 2.8m.
  • the filling volume is 15.4m3, and the total filling coal seam and similar materials can reach 30 tons (the average bulk density of similar materials is 2000kg/m3). Therefore, the present invention has a large filling volume and satisfies the simulation of similar materials in the goaf on a larger scale.
  • the existing goaf coal spontaneous combustion simulation experiment device cannot simulate the collapse of the leftover coal in the goaf and the collapse of the roof of the goaf, so it is impossible to more realistically simulate the occurrence of the leftover coal in the goaf and the roof and floor.
  • the state includes the loose and broken state of the leftover coal, the compaction of the leftover coal in the goaf, the fissure channels around the goaf, and the air leakage status.
  • the experimental device of the present invention simulates the collapse of the remaining coal in the goaf and the collapse of the roof of the goaf by discharging the embedded water bag, thereby more realistically simulating the occurrence state of the remaining coal in the goaf and the roof and floor, including the remaining coal
  • the loose and broken state of the coal mine, the compaction of the remaining coal in the goaf, the fissure channels around the goaf and the air leakage conditions are examples of the remaining coal in the goaf and the collapse of the roof of the goaf by discharging the embedded water bag, thereby more realistically simulating the occurrence state of the remaining coal in the goaf and the roof and floor, including the remaining coal
  • the experimental furnace body can be laid with similar materials for multi-layer coal seam floor, coal seams and multi-layer roof rock layers, which can better simulate the occurrence state of coal seams and roof and floor in the goaf;
  • the device can construct a large-scale coal mining face, air intake lane, return air lane and goaf system, and use arch hollow protection pipes to simulate the air intake lane, working face and return air lane of the working face production system. It can also simulate the air leakage conditions in the air intake lane and the working face in the goaf area.
  • the experimental device realizes the natural collapse of the leftover coal and roof in the goaf by discharging the embedded water bag, and better simulates the simulation state of the leftover coal and the collapsed rock in the goaf.
  • the experimental device can simulate the spontaneous combustion process of coal in the goaf under certain conditions and simulate one or more factors affecting the spontaneous combustion of coal by using the controlled variable method.

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Abstract

一种模拟采空区自然发火的实验方法，利用模拟采空区自然发火的实验装置，实验装置的实验炉体上设有出煤口（6）、进风管（19）和回风管（20）；实验炉体内设有煤层（8）、相似材料底板（9）、预置水袋（10）、待下沉相似材料底板（11）、第一相似材料顶板（12）和第二相似材料顶板（13），第二相似材料顶板（13）上方设有多点热电偶测杆（15）和取气束管（17），多点热电偶测杆（15）之间设有覆盖层（14），多点热电偶测杆（15）设有若干热电偶（16），多点热电偶测杆（15）和取气束管（17）与相似材料紧密接触；煤层（8）上的采煤工作面（21）两端设有进风巷（32）和回风巷（33），在进风巷（32）、采煤工作面（21）和回风巷（33）铺设拱形镂空护管（18），支撑煤体形成一定的通道空间，以构建采空区和工作面的进回风系统。利用该实验方法可以在实验室准确有效地模拟漏风条件下采空区煤自然发火的全过程。

Description

一种模拟采空区自然发火的试验方法 技术领域
本发明属于采矿工程领域，涉及一种模拟采空区自然发火的试验方法。
 背景技术
煤炭自燃是煤炭开采和储运过程中常见的灾害之一，造成资源的极大浪费，严重威胁人们的生命财产。以往研究表明，煤自燃的发生和发展是一个极其复杂的、动态变化的、自动加速的物理化学过程，加上煤是一种物理结构和化学矿物质组成极其复杂的不均匀体，其确切的分子结构模型尚无定论，很难从理论上搞清煤自燃发生和发展的过程。另外，由于煤自燃常发生于地下数百米深处的采空区，人员无法接近，火源的隐蔽性，使得自燃火源位置的精确探测成为防灭火的关键技术。迄今为止，国内外还没有一种十分有效的探测方法来准确对煤炭自燃进行早期预报和确定其位置。
其他的相关研究主要从耗氧量或者温度指标评判煤的自燃倾向性，实验条件较现实中采空区实际赋存条件差别较大。煤自燃过程不仅与煤自身的氧化性和放热性有关，还与漏风供氧和蓄热环境密切相关。煤自燃是煤体放热和环境散热这对矛盾动态发展的过程，所以煤的自燃特征参数及其影响因素既与煤的自身物理条件有关，又与外界条件，比如堆积压力、漏风条件、环境温湿度等有关。
本发明专利主要解决如何相似模拟煤层煤岩赋存状态、采空区漏风条件、煤层顶板的自然垮落和遗煤的自然分布，实验不同煤种、通风流量、氧浓度、煤厚等条件下的采空区煤自燃过程，研究煤最短自然发火期以及各指标临界值，监测自燃过程温度、气体组分变化，对煤的氧化性、放热性、煤自燃影响因素及煤自燃过程中的其它一些特性参数进行研究，并提出煤自燃过程判断指标，对煤的自燃机理进行研究的问题，从而实现对煤炭自燃进行早期预报。因此，本发明专利设计了一套煤自然发火全过程的相似模拟实验装置及方法，满足了对煤最短自然发火期测定、气体分析和煤岩温度变化规律特性研究的实验要求。
煤炭自燃火灾严重威胁着煤矿的安全生产，为了杜绝此类火灾的发生，煤炭自然发火的早期预测预报功能越来越受到重视。煤炭自然发火预测预报是对煤炭火灾参数指标进行超前早期识别和预警的根本技术手段。通过对煤炭自燃火灾指标气体及其生成的辅助性指标的超前判识，及时、准确地预测预报煤炭自然发火征兆，推断自然发火发展的趋势，为煤炭自然发火的防治提供科学的依据，有针对性地采取均压、密闭堵漏、预灌浆等措施进行治理，将火灾隐患消灭在萌芽状态，从根本上做到防患于未然，达到防止火灾或减少火灾损失的目的。
以往研究表明，煤自燃的发生和发展是一个极其复杂的、动态变化的、自动加速的物理化学过程，加上煤是一种物理结构和化学矿物质组成极其复杂的不均匀体，其确切的分子结构模型尚无定论，很难从理论上搞清煤自燃发生和发展的过程。另外，由于煤自燃常发生于地下数百米深处的采空区，人员无法接近，火源的隐蔽性，使得自燃火源位置的精确探测成为防灭火的关键技术。迄今为止，国内外还没有一种十分有效的探测方法来准确对煤炭自燃进行早期预报和确定其位置。
物理模型试验是将现场实际的赋存及条件按一定相似比置于实验室内，以相似理论为基础，在满足基本相似条件（包括几何、运动、热力、动力和单值条件相似）下，通过在模型试验所获得的某些参数间的规律再回推到原型上，从而获得对原型的规律性认识，以此模拟真实过程主要特征的试验方法。近年来，物理模型试验因其直观、便于测量等特点被广泛用于煤矿开采过程中各类安全问题研究当中。在物理模型试验中，尽量真实地模拟采空区煤自燃的顶底板条件、遗煤状态，对于开展采空区煤自燃主要影响因素、自燃特性以及机理的研究具有重要的作用。
因此，研究发明一种模拟煤自然发火的实验装置及方法，实验不同煤种、通风流量、氧浓度、煤厚等条件下的煤自燃过程，研究煤最短自然发火期以及各指标临界值，监测自燃过程温度、气体组分变化，对煤的氧化性、放热性、煤自燃影响因素及煤自燃过程中的其它一些特性参数进行研究，并提出煤自燃过程判断指标，对煤炭自燃进行早期预报的研究，具有至关重要的意义。
煤自燃的发生和发展是一个极其复杂的动态变化的物理化学过程，其实质就是一个缓慢地氧化自动放热升温最后引起燃烧的过程。该过程的关键有两点：一是热量的自发产生；二是热量的逐渐积聚。采空区内气体运移及气体成份变化受采场配风、相连巷道漏风及采场地质条件等综合作用影响，采空区漏风也是造成采空区发生自然发火的主要原因。因此，对煤自然发火进行模拟，就需要煤自然发火模拟实验装置具有足够大的尺寸，满足对其地质条件、漏风条件、浮煤分布条件等因素的模拟，从而为对煤自然发火机理和煤自然发火预报技术的研究创造条件。而现有的煤自然发火实验装置不能有效模拟采空区的地质条件、采空区的漏风条件。
根据查阅已公开中国专利，公开号CN 107247127 A的中国专利“考虑大气压的采空区自然发火模型试验平台及试验方法”包括正压通风机、热电偶、实验箱体、空气加湿器、空气加热器、进气管、出气管等。该技术方案在试验箱体内进行，实验空间狭小，不能模拟采空区煤层覆岩的赋存状态，不能有效模拟采场配风巷道漏风条件，不能有效模拟采空区的垮落和遗煤的分布状态。
现有技术的缺点包括：
（1）现有采空区煤自燃模拟实验装置尺寸小，因此难以从较大空间尺度上更真实地模拟采空区遗煤自燃过程；
（2）现有的采空区煤自燃模拟实验装置内部无法铺设煤层顶底板相似材料，或者铺设高度有限，因此无法更真实地模拟采空区遗煤的顶底板赋存条件；
（3）现有的采空区煤自燃模拟实验装置无法模拟采空区遗煤垮落以及采空区顶板的垮落过程，因此无法更真实地模拟采空区遗煤以及顶底板的赋存状态，包括遗煤的松散破碎状态、采空区遗煤的压实情况、采空区周边的裂隙通道及漏风状况。
 技术解决方案
本发明的目的在于提供一种模拟采空区自然发火的试验方法，本发明的有益效果是可以在实验室准确有效地模拟漏风条件下采空区煤自然发火的全过程，模拟大空间尺度内采空区煤岩赋存状态、采空区顶煤和顶板的自然垮落、遗煤的分布状态，监测采空区范围内温度场分布及演化规律；同时可以对采空区不同位置进行分布式束管取气，通过气相色谱仪分析得到不同位置气体组分及浓度分布和演化规律；分析采空区遗煤自燃过程中指标气体的组分、浓度及随时间变化规律，得到采空区遗煤自然发火期。从而为采空区煤自然发火机理的研究和采空区自燃三带的划分创造良好的实验条件。
模拟采空区自然发火的实验装置所采用的技术方案是包括实验炉体，实验炉体由外至内分为炉体外层钢板、普通砖层、聚氨酯隔热层、水夹层、耐火砖层，实验炉体上设有出煤口、进风管和回风管，实验炉体上方设有顶盖；实验炉体内设有煤层，煤层下方设有相似材料底板和预置水袋，预置水袋上方设有待下沉相似材料底板，煤层上方设有第一相似材料顶板和第二相似材料顶板，第二相似材料顶板上方设有多点热电偶测杆和和取气束管，多点热电偶测杆之间设有覆盖层，多点热电偶测杆设有若干热电偶，多点热电偶测杆和取气束管与相似材料紧密接触；煤层上的采煤工作面两端设有进风巷和回风巷，在进风巷、采煤工作面和回风巷铺设拱形镂空护管，支撑煤体形成一定的通道空间，以构建采空区和工作面的进回风系统，进风巷与实验炉上的进风管相连，回风巷与实验炉上的回风管相连。
进一步，进风管依次连接实验炉体外部的涡街流量计、气体测温热电偶、气体压力表、换热器、鼓风机，换热器连接换热器控制柜。
进一步，回风管依次连接实验炉体外部的涡街流量计、气体测温热电偶、气体压力表、气相色谱仪、气体采集器；所述出煤口连接气体采集器和数据采集模块；数据采集模块和气相色谱仪连接工控机。
    本发明另一种模拟采空区自然发火的实验方法按照以下步骤进行：
步骤1，相似材料的选取；以河砂为骨料，粘土、石膏为胶结物，利用正交试验和全面实验方法分析不同材料配比下的单轴抗压强度，并与利用相似原理计算的抗压强度进行对比，确定满足相似比的不同顶底板岩层河砂和粘土配比；在工作现场采集所需煤块，作为实验用煤，选取黄土作为覆盖层，根据现场实际厚度的1/10~1/30的几何缩放比确定煤层和顶底板相似材料的厚度，基于相似材料配比铺设煤层及顶底板相似材料；
步骤2，模拟采空区系统的构建；通过铺设拱形镂空护管构建采空区及工作面的进风巷、回风巷和采煤工作面；将进风管、进风巷、采煤工作面、回风巷以及回风管构成模拟采空区及工作面系统的进回风系统，进风巷、采煤工作面和回风巷均由拱形镂空护管构建，模拟进风巷和工作面向采空区内的漏风；
步骤3，测温和取气布置；在铺设采空区煤层及第一相似材料煤层顶板、第二相似材料煤层顶板、覆盖层的同时，在相应位置点埋设多点热电偶测杆和取气束管，测杆和取气束管与第一相似材料煤层顶板、第二相似材料煤层顶板、覆盖层紧密接触，取气束管取气口有防尘保护；
多点热电偶测杆高度方向由下到上共布置多个热电偶测点，能监测到采空区底板到顶板不同高度上的温度值，热电偶测杆呈网格化布置，可以监测到整个采空区三维空间的温度值；
取气束管在采空区范围内呈网格化分布，每个位置的取气束管对采空区高度方向上的多个位置点进行取气，从而分析得到采空区三维空间的气体组分、浓度分布和演化规律；
步骤4，相似模拟材料及采空区系统的铺设；在实验炉体内自下而上敷设相似材料底板、煤层、第一相似材料顶板、第二相似材料顶板和表层覆盖层，边铺设边进行压实处理，待胶结后具有一定的强度，满足采空区顶底板岩层强度相似比的要求；
在底板材料的铺设过程中，在采空区范围内提前预置一定高度的水袋，水袋高度等同于模拟的采高，在煤层采高范围预先填充底板相似材料，其上为采空区煤层遗煤；
从煤层开始，在进风巷、采煤工作面和回风巷铺设拱形镂空护管，支撑煤体形成一定的通道空间，以构建采空区和工作面的进回风系统，进风巷与实验炉上的进风管相连，回风巷与实验炉上的回风管相连；
步骤5，采空区顶煤垮落过程的模拟；当相似模拟材料及采空区系统的铺设完毕后，将水袋的水抽出一定体积的水，使水袋放出水的高度等同于煤层采高，水袋及其上待下沉相似材料底板向下移动并填满水袋放出水高度，通过此方式造成采空区上部顶遗煤的垮塌，采空区顶煤自然垮落覆盖在采空区底板，模拟采空区遗煤的堆积分布，同时还能模拟遗煤之上的覆岩的跨落和弯曲，制造孔隙和裂隙，形成上三带结构；
步骤6，采空区煤自然发火过程的模拟；采空区遗煤堆积在采空区，由于进风巷和采煤工作面的漏风，导致采空区内遗煤与氧气接触，在煤氧的物理吸附、化学吸附和氧化反应作用下，产生微小的热量，且在一定条件下氧化产热速率大于向环境的散热速率，产生热量积聚使得煤体温度缓慢而持续地上升，当达到煤的临界自热温度后，氧化升温速率加快，最后达到煤的着火点温度而燃烧起来，达到模拟煤自然发火过程目的；
进一步，进风参数由布置于进气管路上的所述气体测温热电偶、气体压力表、涡街流量计设备监测；回风参数由布置于回风管路上的所述气体测温热电偶、气体压力表、涡街流量计、气相色谱仪设备监测；采空区监测点温度值由布置于采空区内的所述多点热电偶测杆内的热电偶监测；采空区监测点气体组分和浓度值由布置于采空区内的所述取气束管和气相色谱仪设备监测；所有监测数据通过数据采集模块采集并输送到工控机，由相关监测软件进行数据的记录、分析和存储。
本发明的目的就是要从较大的空间尺度，更加真实地模拟采空区遗煤顶底板赋存条件；通过模拟采空区开采后顶板遗煤以及顶板的垮落过程，更真实地模拟采空区遗煤已经顶底板的赋存状态，包括遗煤的松散破碎状态、采空区遗煤的压实情况、采空区周边的裂隙通道及漏风状况。为开展采空区煤自燃过程及主要影响因素的模拟提供基础物理模型条件。
 有益效果
本发明的有益效果是可以在实验室准确有效地模拟漏风条件下采空区煤自然发火的全过程，模拟大空间尺度内采空区煤岩赋存状态、采空区顶煤和顶板的自然垮落、遗煤的分布状态，监测采空区范围内温度场分布及演化规律；同时可以对采空区不同位置进行分布式束管取气，通过气相色谱仪分析得到不同位置气体组分及浓度分布和演化规律；分析采空区遗煤自燃过程中指标气体的组分、浓度及随时间变化规律，得到采空区遗煤自然发火期。从而为采空区煤自然发火机理的研究和采空区自燃三带的划分创造良好的实验条件。
 附图说明
图1为采空区煤自燃模拟实验装置侧面剖视图；
图2为采空区煤自燃模拟实验装置遗煤和放水后的水袋示意图；
图3为采空区煤自燃模拟实验装置俯视图；
图4位本发明模拟采空区自然发火的实验方法示意图。
图中，1. 实验炉外钢板，2. 普通砖层，3. 聚氨酯绝热层，4. 水夹层，5. 耐火砖层，6. 出煤口，7. 顶盖，8.煤层，801. 遗煤，9. 相似材料底板，10. 预置水袋，11. 待下沉相似材料底板，12. 第一相似材料煤层顶板，13. 第二相似材料煤层顶板，14. 覆盖层，15. 多点热电偶测杆，16. 热电偶，17. 取气束管，18. 拱形镂空护管，19. 进风管，20. 回风管，21. 模拟的采煤工作面，22. 鼓风机，23. 换热器，24. 换热器控制柜，25. 气体压力表，26. 气体测温热电偶，27. 涡街流量计，28. 数据采集模块，29. 气体采集器，30. 气相色谱仪，31. 工控机，32. 进风巷，33. 回风巷。
 本发明的实施方式
下面结合具体实施方式对本发明进行详细说明。
主要包括实验炉体部分、采空区相似材料部分、供风和排气部分、气体采集与分析部分、自动测温和监控系统五部分组成。
所述实验炉体如图1至图3所示，包括：炉体外层钢板1、普通砖层2、聚氨酯隔热层3、水夹层4、耐火砖层5、进风管19、回风管20、顶盖7、出煤口6、进风管19和回风管20、进风巷32、回风巷33、拱形镂空护管18。本发明实验炉体整体为圆柱体，实验炉外径为3.73m，实验炉体内内径为2.8m，实验炉体内净高为2.5m。
采空区相似材料部分包括：煤层8和遗煤801、相似材料底板9、预置水袋10、待下沉相似材料底板11、第一相似材料顶板12和第二相似材料顶板13、覆盖层14、模拟的采煤工作面21、拱形镂空护管18、进风巷32、回风巷33。所述采空区范围为1.4m×1.4m区域，采空区高度与所铺设煤层高度相同。
供风和排气部分包括：鼓风机22、换热器23、换热器控制柜24、气体压力表25、气体测温热电偶26、涡街流量计27。
气体采集与分析部分包括：取气束管17、气体采集器29、气相色谱仪30。
自动测温和监控系统部分包括：多点热电偶测杆15、热电偶16、数据采集模块28、工控机31。
本发明模拟采空区自然发火的实验方法如图4所示包括以下步骤：
步骤1，相似材料的选取。
根据相似原理理论，以河砂为骨料，粘土、石膏为胶结物，利用正交试验和全面实验方法分析不同材料配比下的单轴抗压强度，并与利用相似原理计算的抗压强度进行对比，确定满足相似比的不同顶底板岩层河砂和粘土配比；在工作现场采集所需煤块，作为实验用煤。选取黄土作为覆盖层。根据现场实际厚度的1/10~1/30的几何缩放比确定煤层和顶底板相似材料的厚度，基于相似材料配比铺设煤层及顶底板相似材料。
步骤2，模拟采空区系统的构建。
通过铺设拱形镂空护管18构建采空区及工作面的进风巷32、回风巷33和采煤工作面21。
所述实验炉进风管19、进风巷32、采煤工作面21、回风巷33以及回风管20构成了模拟采空区及工作面系统的进回风系统，进风巷32、采煤工作面21和回风33巷均由拱形镂空护管18构建，可模拟进风巷32和工作面21向采空区内的漏风。
步骤3，测温和取气布置。
在铺设采空区煤层8及顶板相似材料（12、13、14）的同时，在相应位置点埋设多点热电偶测杆15和取气束管17，测杆15和取气束管17与相似材料紧密接触，取气束管17取气口有防尘保护。
所述多点热电偶测杆15高度方向由下到上共布置多个热电偶16测点，能监测到采空区底板到顶板不同高度上的温度值。热电偶测杆15呈网格化布置，可以监测到整个采空区三维空间的温度值。
所述取气束管17在采空区范围内呈网格化分布，每个位置的取气束管17可对采空区高度方向上的多个位置点进行取气，从而分析得到采空区三维空间的气体组分、浓度分布和演化规律。
步骤4，相似模拟材料及采空区系统的铺设。
在实验炉体内自下而上敷设相似材料底板9、煤层8、相似材料顶板12和13及表层覆盖层14，边铺设边进行压实处理，待胶结后具有一定的强度，满足采空区顶底板岩层强度相似比的要求。
在底板材料的铺设过程中，在采空区范围内提前预置一定高度的水袋10，水袋10高度应等同于模拟的采高。在煤层采高范围预先填充底板相似材料11，其上为采空区煤层遗煤801。
从煤层8开始，在进风巷32、采煤工作面21和回风巷33铺设拱形镂空护管18，支撑煤体形成一定的通道空间，以构建采空区和工作面的进回风系统。所述进风巷32与实验炉上的进风管19相连，回风巷33与实验炉上的回风管20相连。
步骤5，采空区顶煤垮落过程的模拟。
当实验炉体内煤层8和相似材料（12、13、14）敷设完毕后，将水袋10的水抽出一定体积的水，使水袋10放出水的高度等同于煤层采高，所述水袋10及其上待下沉相似材料底板11向下移动并填满水袋10放出水高度。通过此方式造成采空区上部顶遗煤801的垮塌，并有可能造成覆岩12的垮落和移动。采空区顶煤自然垮落覆盖在采空区底板，模拟采空区遗煤801的堆积分布，同时还可模拟遗煤之上的覆岩的跨落和弯曲，制造孔隙和裂隙，形成“上三带”结构。
步骤6，采空区煤自然发火过程的模拟。
采空区遗煤801堆积在采空区，由于进风巷32和采煤工作面21的漏风，导致采空区内遗煤801与氧气接触，在煤氧的物理吸附、化学吸附和氧化反应作用下，产生微小的热量，且在一定条件下氧化产热速率大于向环境的散热速率，产生热量积聚使得煤体温度缓慢而持续地上升，当达到煤的临界自热温度后，氧化升温速率加快，最后达到煤的着火点温度而燃烧起来，由此称之为煤自然发火（或煤自燃）过程。
煤自燃是煤的氧化产热与向环境散热的矛盾发展的结果，因此只要与煤自燃过程产热和热量向环境散热相关的因素都能影响煤的自然发火过程。可分为内在因素和外在因素。其内在因素包括煤化程度、煤的水分、煤岩成分、煤的含硫量、煤的粒度与孔隙结构、煤的瓦斯含量；其外在因素包括煤层地质赋存条件（煤层厚度、倾角、埋藏深度、地质构造及围岩性质）、采掘技术因素（采区回采速度、回采期、采空区丢煤量及其集中程度、顶板管理方法、煤柱及其破坏程度、采空区封闭难易等）、通风管理因素（采空区漏风量）。
本发明所述的一种模拟采空区自然发火的实验装置，既可以对某一特定条件下的采空区进行煤自然发火过程的模拟；又可以采用控制变量法，对影响煤自燃的一个或多个因素开展试验研究。
上述步骤6中对某一特定条件下的采空区煤自然发火过程的模拟子步骤包括：根据现场采空区的实际情况，包括上述内在因素和外在因素，在实验室尺度采用相似理论模拟采空区煤自然发火过程，得到采空区自然发火期；采空区自燃高温区范围及扩展规律，包括着火点（火源）位置、范围、着火强度，温度场分布的研究；采空区自燃指标气体浓度、组分、分布及扩展规律；采空区“三带”（不自燃带、自燃带和窒息带）分布范围等。
上述步骤6中采用控制变量法对影响煤自燃的一个或多个因素开展试验研究的子步骤包括：选取上述内在因素和外在因素中的一个或多个影响因素，通过该因素的数值变化，研究该因素对煤自然发火过程的影响程度，分析该因素变化对煤自燃主要特征（如自然发火期、温度场、浓度场分布、指标气体变化规律等）、自然发火期以及采空区的影响规律。
步骤7：数据监测与分析。
本发明所述实验过程中的主要监测数据为：进风参数（温度、压力、流量）、回风参数（温度、压力、流量、气体组分）、采空区监测点温度值、采空区监测点气体组分和浓度值。
所述进风参数由布置于进气管路上的气体测温热电偶26、气体压力表25、涡街流量计27等设备监测；所述回风参数由布置于回风管路上的气体测温热电偶26、气体压力表25、涡街流量计27、气相色谱仪30等设备监测；所述采空区监测点温度值由布置于采空区内的多点热电偶测杆15内的热电偶16监测；所述采空区监测点气体组分和浓度值由布置于采空区内的取气束管17和气相色谱仪30等设备监测。
所有监测数据通过数据采集模块28采集并输送到工控机31，由相关监测软件进行数据的记录、分析和存储。
本发明相对其他现有实验装置其优点如下：
（1）现有采空区煤自燃模拟实验装置尺寸小，因此难以从较大空间尺度上更真实地模拟采空区遗煤自燃过程。本发明实验装置内径为2.8m，内高为2.5m，可模拟采空区范围为1.4m×1.4m。
（2）现有的采空区煤自燃模拟实验装置内部无法铺设煤层顶底板相似材料，或者铺设高度有限，因此无法更真实地模拟采空区遗煤的顶底板赋存条件。本发明实验炉体整体为圆柱体，内净高为2.5m，即可以铺设多层的相似材料底板、煤层以及相似材料顶板，总高度可达2.8m，实验炉体内径为2.8m，总内部填充体积为15.4m3，总填充煤层和相似材料可达30吨（平均相似材料容重为2000kg/m3）。因此，本发明填充量大，满足了较大尺度的采空区相似材料模拟。
（3）现有的采空区煤自燃模拟实验装置无法模拟采空区遗煤垮落以及采空区顶板的垮落过程，因此无法更真实地模拟采空区遗煤已经顶底板的赋存状态，包括遗煤的松散破碎状态、采空区遗煤的压实情况、采空区周边的裂隙通道及漏风状况。本发明实验装置通过对预埋水袋放水模拟采空区遗煤垮落以及采空区顶板的垮落过程，因而更真实地模拟采空区遗煤已经顶底板的赋存状态，包括遗煤的松散破碎状态、采空区遗煤的压实情况、采空区周边的裂隙通道及漏风状况。
（4）实验炉体内部可铺设多层煤层底板相似材料、煤层和多层顶板岩层相似材料，能够更好地模拟采空区煤层和顶底板的赋存状态；
（5）该装置可构建大尺度采煤工作面、进风巷、回风巷和采空区系统，采用拱形镂空护管模拟工作面生产系统的进风巷、工作面和回风巷，并可模拟进风巷和工作面向采空区范围内的漏风条件。
（6）该实验装置通过对预埋水袋放水，实现对采空区遗煤和顶板的自然垮落，更好地模拟采空区遗煤和垮落岩石的模拟状态。
（7）该实验装置可进行某一特定条件下的采空区煤自然发火过程模拟以及通过采用控制变量法对影响煤自燃的一个或多个因素开展试验研究的模拟。
    以上所述仅是对本发明的较佳实施方式而已，并非对本发明作任何形式上的限制，凡是依据本发明的技术实质对以上实施方式所做的任何简单修改，等同变化与修饰，均属于本发明技术方案的范围内。

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  1. 一种模拟采空区自然发火的实验方法，其特征在于，利用模拟采空区自然发火的实验装置：实验炉体由外至内分为炉体外层钢板、普通砖层、聚氨酯隔热层、水夹层和耐火砖层，实验炉体上设有出煤口、进风管和回风管，实验炉体上方设有顶盖；试验方法的步骤包括：
    步骤1，相似材料的选取；以河砂为骨料，粘土、石膏为胶结物，利用正交试验和全面实验方法分析不同材料配比下的单轴抗压强度，并与利用相似原理计算的抗压强度进行对比，确定满足相似比的不同顶底板岩层河砂和粘土配比；在工作现场采集所需煤块，作为实验用煤，选取黄土作为覆盖层，铺设煤层及顶底板相似材料；
    步骤2，模拟采空区系统的构建；通过铺设拱形镂空护管构建采空区及工作面的进风巷、回风巷和采煤工作面；将进风管、进风巷、采煤工作面、回风巷和回风管构成模拟采空区及工作面系统的进回风系统；
    步骤3，测温和取气布置；在铺设采空区煤层及第一相似材料煤层顶板、第二相似材料煤层顶板、覆盖层的同时，在相应位置点埋设多点热电偶测杆和取气束管，测杆和取气束管与第一相似材料煤层顶板、第二相似材料煤层顶板、覆盖层紧密接触，取气束管取气口有防尘保护；
    多点热电偶测杆高度方向由下到上共布置多个热电偶测点，能监测到采空区底板到顶板不同高度上的温度值，热电偶测杆呈网格化布置；
    取气束管在采空区范围内呈网格化分布，每个位置的取气束管对采空区高度方向上的多个位置点进行取气，从而分析得到采空区三维空间的气体组分、浓度分布和演化规律；
    步骤4，相似模拟材料及采空区系统的铺设；在实验炉体内自下而上敷设相似材料底板、煤层、第一相似材料顶板、第二相似材料顶板和表层覆盖层，边铺设边进行压实处理；
    在底板材料的铺设过程中，在采空区范围内提前预置水袋，水袋高度等同于模拟的采高，在煤层采高范围预先填充底板相似材料，其上方为采空区煤层遗煤；
    从煤层开始，在进风巷、采煤工作面和回风巷铺设拱形镂空护管，支撑煤体形成通道空间，以构建采空区和工作面的进回风系统；
    步骤5，采空区顶煤垮落过程的模拟；当相似模拟材料及采空区系统的铺设完毕后，将水袋的水抽出，使水袋减小的高度等同于煤层的采高，水袋及其上待下沉相似材料底板向下移动并填满水袋放出水的高度，采空区上部顶遗煤垮塌，采空区顶煤自然垮落覆盖在采空区底板，模拟采空区遗煤的堆积分布，同时还能模拟遗煤之上的覆岩的跨落和弯曲，制造孔隙和裂隙，形成上三带结构；
    步骤6，采空区煤自然发火过程的模拟；遗煤堆积在采空区，采空区内遗煤与氧气接触，当氧化产热速率大于向环境的散热速率，产生热量积聚使得煤体温度持续地上升，达到煤的着火点温度而燃烧起来，模拟煤自然发火的过程。
  2. 按照权利要求1所述一种模拟采空区自然发火的实验方法，其特征在于：进风参数由布置于进气管路上的所述气体测温热电偶、气体压力表、涡街流量计设备监测；回风参数由布置于回风管路上的所述气体测温热电偶、气体压力表、涡街流量计、气相色谱仪设备监测；采空区监测点温度值由布置于采空区内的所述多点热电偶测杆内的热电偶监测；采空区监测点气体组分和浓度值由布置于采空区内的所述取气束管和气相色谱仪设备监测；所有监测数据通过数据采集模块采集并输送到工控机，由相关监测软件进行数据的记录、分析和存储。
  3. 按照权利要求1所述一种模拟采空区自然发火的实验方法，其特征在于：所述进风管依次连接实验炉体外部的涡街流量计、气体测温热电偶、气体压力表、换热器、鼓风机，换热器连接换热器控制柜。
  4. 按照权利要求1所述一种模拟采空区自然发火的实验方法，其特征在于：所述回风管依次连接实验炉体外部的涡街流量计、气体测温热电偶、气体压力表、气相色谱仪、气体采集器；所述出煤口连接气体采集器和数据采集模块；数据采集模块和气相色谱仪连接工控机。
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CN114217009A (zh) * 2021-12-24 2022-03-22 中国科学技术大学 一种适用于气体、液体灭火剂性能评估的装置
CN114722742A (zh) * 2022-05-16 2022-07-08 中国矿业大学(北京) 一种采空区多孔介质气体弥散系数测定方法
CN114935614A (zh) * 2022-05-24 2022-08-23 安徽理工大学 一种分析煤体复燃特性的模拟实验装置及实验方法
CN114964661A (zh) * 2022-05-27 2022-08-30 武汉联讯光电技术有限公司 一种基于人工智能的井下煤矿自燃火灾束管监测系统
CN116608003A (zh) * 2023-05-25 2023-08-18 中国矿业大学 一种矿井煤与瓦斯共采复合灾害模拟试验系统及方法
CN116927856A (zh) * 2023-09-05 2023-10-24 内蒙古满世煤炭集团罐子沟煤炭有限责任公司 一种基于传感器的特厚煤层采空区自燃监测管理系统

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CN113960243A (zh) * 2021-11-02 2022-01-21 宁波工程学院 一种快速确定煤绝热自然发火期的对照实验系统与方法
CN114217009A (zh) * 2021-12-24 2022-03-22 中国科学技术大学 一种适用于气体、液体灭火剂性能评估的装置
CN114722742A (zh) * 2022-05-16 2022-07-08 中国矿业大学(北京) 一种采空区多孔介质气体弥散系数测定方法
CN114935614A (zh) * 2022-05-24 2022-08-23 安徽理工大学 一种分析煤体复燃特性的模拟实验装置及实验方法
CN114935614B (zh) * 2022-05-24 2024-02-23 安徽理工大学 一种分析煤体复燃特性的模拟实验装置及实验方法
CN114964661A (zh) * 2022-05-27 2022-08-30 武汉联讯光电技术有限公司 一种基于人工智能的井下煤矿自燃火灾束管监测系统
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CN116608003B (zh) * 2023-05-25 2023-11-24 中国矿业大学 一种矿井煤与瓦斯共采复合灾害模拟试验系统及方法
CN116927856A (zh) * 2023-09-05 2023-10-24 内蒙古满世煤炭集团罐子沟煤炭有限责任公司 一种基于传感器的特厚煤层采空区自燃监测管理系统
CN116927856B (zh) * 2023-09-05 2024-08-02 内蒙古满世煤炭集团罐子沟煤炭有限责任公司 一种基于传感器的特厚煤层采空区自燃监测管理系统

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