Comprehensive Test Device for Thermokinetic Characteristics of Coal Spontaneous Combustion Oxidation under Open Environment Program Temperature Control

Abstract

The present invention discloses a comprehensive test device for the kinetic characteristics of coal spontaneous combustion oxidation under program temperature control in an open environment, which includes a gas supply device, a non-adiabatic heating furnace, a rapid heating / cooling device, a temperature / image / mass / gas measurement device, a data terminal, and an exhaust gas treatment device. Among them, the gas supply device ensures uniform gas supply through an elastic airbag; the wire basket in the non-adiabatic heating furnace contains coal samples and is in direct contact with the air in the furnace, approaching the real environment; the microcrystalline glass wavy heating plate realizes rapid heating; the air-cooling and water-cooling devices work together to achieve rapid cooling; the imaging device observes the coal body morphology in all directions; the weighing device eliminates environmental disturbances and accurately weighs; the infrared gas detection and chromatographic column meet the requirements of rapid and accurate gas measurement; the data terminal receives and processes detection information to determine the characteristics of coal spontaneous combustion; the exhaust gas treatment device purifies and treats exhaust gas. The device of the present invention has a high adaptability to the real mine environment, fast heating / cooling speed, accurate and comprehensive measurement data, and significantly improves the research efficiency of coal spontaneous combustion characteristics.

Description

Technical Field

[0001] The invention discloses an open environment programmed temperature controlled coal spontaneous combustion oxidation kinetic characteristics comprehensive testing device, which involves the testing of coal spontaneous combustion characteristic temperature, image, quality and gas, can overcome the drawbacks of traditional testing methods, significantly improve the test accuracy, and belongs to the technical field of coal spontaneous combustion characteristic testing. Background Art

[0002] The test of coal spontaneous combustion oxidation kinetic characteristics in the laboratory can predict the spontaneous combustion tendency of coal to a certain extent and provide guidance for actual field work.

[0003] At present, the test of coal spontaneous combustion oxidation kinetic characteristics mostly adopts adiabatic programmed temperature chromatography, which has the advantages of simple operation and fixed program, but still has some disadvantages, mainly reflected in the adiabatic heating environment does not match the actual production state, the gas supply is difficult to allocate a special ratio, the quality change cannot be monitored, the data presentation form is single, etc. Therefore, in order to conduct a more accurate analysis of the spontaneous combustion and ignition characteristics of coal, a comprehensive test device for the spontaneous combustion and oxidation kinetic characteristics of coal is urgently needed, which can simulate the real environment and measure the data comprehensively and accurately. Summary of the invention

[0004] In view of this, the present invention provides an open environment programmed temperature controlled coal spontaneous combustion oxidation kinetic characteristics comprehensive testing device, which can be used to simulate the coal spontaneous combustion evolution process in a real mine environment under different conditions and determine the coal spontaneous combustion oxidation kinetic characteristics.

[0005] To achieve the above-mentioned purpose, the present invention provides an open environment program temperature controlled coal spontaneous combustion oxidation dynamics characteristics comprehensive testing device, including a gas supply device, a non-adiabatic heating furnace, a rapid heating / cooling device, a temperature measuring device, a camera device, a precise weighing device, a gas detection device, an exhaust gas treatment device, and a data terminal;

[0006] The gas supply device is tightly connected to the non-insulated heating furnace to ensure the gas tightness of the device and avoid insufficient gas supply due to gas leakage;

[0007] The non-adiabatic heating furnace is an open environment, and the inner mesh basket is provided with uniform small holes around it, so that the coal sample is in direct contact with the air in the furnace, thus achieving non-adiabatic heating;

[0008] The rapid heating device adopts a microcrystalline glass corrugated heating plate, which is installed on the top, bottom and three sides of the heating furnace to increase the heating speed of the coal sample in the non-adiabatic heating furnace;

[0009] The rapid cooling device is composed of a water cooling device and an air cooling device, which accelerates the cooling speed of the environment in the non-adiabatic heating furnace after the experiment and improves the experimental efficiency;

[0010] The temperature measuring device is arranged in the vertical detection device arrangement groove at the center position of the wire basket cylinder to measure the temperature of coal samples at different positions in real time;

[0011] The camera device is built into the non-adiabatic heating furnace, symmetrically arranged in the center, with a 90° interval around, and can observe phenomena such as coal body flame, flue gas, color, and collapse in all directions;

[0012] The precise weighing device realizes precise weighing and reduces the fluctuation effect by adding a glass shield and metal balls;

[0013] The gas detection device uses a chromatographic column and an infrared gas detection device to complete gas detection and achieve comprehensive monitoring of stable gas-phase products;

[0014] The waste gas treatment device is connected to the non-adiabatic heating furnace and the gas detector, and the excess gas enters the waste gas treatment device to achieve the effect of purifying the gas;

[0015] The data terminal collects the temperature, mass, image, and gas information detected by the detection device, and comprehensively judges the progress stage and tendency of coal spontaneous combustion.

[0016] Further, the gas supply device includes a gas cylinder, a pressure regulating valve, a gas distribution instrument, an elastic airbag, and a flow meter;

[0017] The pressure regulating valve is installed on the gas cylinder, and the gas output pressure of the gas cylinder is controlled by the pressure regulating valve to achieve uniform gas outflow;

[0018] The gas distribution instrument adjusts the gas output flow rate, controls the gas flow, and determines the proportion of different gases according to the size of the flow, creating different gas environments;

[0019] Different gases are mixed in the elastic airbag according to different proportion requirements. The airbag is made of flexible material and is installed between the gas distribution instrument and the non-adiabatic heating furnace. The mixed gas enters the interior of the heating furnace from the air inlet on the bottom side of the heating furnace to avoid uneven gas mixing when contacting the sample;

[0020] The flow meter is installed between the elastic airbag and the non-adiabatic heating furnace to observe whether the gas flow rate supplied to the non-adiabatic heating furnace is consistent with the requirements.

[0021] Further, the non-adiabatic heating furnace includes a shell and a porous wire basket;

[0022] The outer surfaces of the top, bottom, and three sides of the shell are made of stainless steel, and the inner surface is made of high-temperature resistant ceramic plates, which can maintain stable performance at 1500°C for a long time, with strong anti-wear and anti-corrosion capabilities. The space between the inner and outer surfaces is filled with heat-insulating materials such as high-aluminum cotton and ceramic fiber cotton. The multi-layer heat-insulating structure reduces the heat loss inside the non-adiabatic heating furnace;

[0023] On the other side of the housing, double-layer high-vacuum inner cavity high-temperature glass is selected. An efficient getter is placed in the inner cavity to ensure the high vacuum degree between the double-layer glasses. The high-vacuum inner cavity significantly improves the heat insulation performance of the double-layer glass, and the high-temperature glass can withstand a high temperature of 500 °C for a long time;

[0024] The upper wall of the heating furnace is provided with an opening for connecting a gas alarm to give a real-time alarm for over-limit gas;

[0025] The porous wire basket is a cylinder with a height of 10 cm and a radius of 4 cm. The lower cover is fixed and the upper cover is movable. The cylinder is made of transparent high-temperature glass and can withstand a high temperature of 500 °C for a long time. Circular fine holes are evenly laid on the surface, and the hole opening rate is equal to the porosity of the coal surface;

[0026] At the central position of the cylinder of the porous wire basket, there is a vertical detection device arrangement groove. Inside the wire basket, there are three horizontal detection device arrangement grooves with a diameter of 2.5 mm. Circular fine holes are arranged around the detection device arrangement grooves, and the hole opening rate is equal to the porosity of the coal surface to prevent the detection device from affecting the coal structure. A copper ultra-thin filter screen is installed inside the detection device arrangement groove to prevent the coal particles from becoming smaller during the reaction and entering the detection device arrangement groove.

[0027] Furthermore, the rapid heating device adopts a microcrystalline glass wavy heating plate, which is installed on the top, bottom and three sides of the heating furnace;

[0028] The microcrystalline glass heating plate prepares a nano atomization coating on the microcrystalline glass, so that the substance to be heated is rapidly heated under the action of atomic resonance and infrared rays. This material has a fast heating speed, a high effective electro-thermal conversion rate and strong oxidation resistance;

[0029] The heating plate is wavy, and the wavy shape is composed of multiple parabolas. The ratio of the horizontal projection length to the sagitta of the parabola is 4:3, which significantly increases the heating area;

[0030] The heating speed process of the heating plate is controlled by a programmed temperature rise control system. The temperature rise range is 0 - 300 °C, and stepwise temperature rise can be achieved.

[0031] Furthermore, the rapid cooling device includes a water cooling device and an air cooling device;

[0032] The water cooling device consists of a water pump, a radiator, a cooling fan, water cooling pipes and a flow regulating valve. After the experiment, an external water pump is used for circulating flow. The initial flow rate is set to 0.5 m / s. The water stored in the radiator flows along the water cooling pipes in the non-adiabatic heating furnace for cooling, and after flowing out, it is cooled by the cooling fan and then circulates back into the non-adiabatic heating furnace;

[0033] The radiator is made of stainless steel structure, and a graphene heat dissipation film is laid on the surface, which is in a flat corrugated shape to increase the heat dissipation area and improve the cooling speed of the circulating water;

[0034] The water-cooled pipes are made of stainless steel, with graphene heat dissipation films laid on the surface. They are arranged on three sides and the bottom of the building, located at the rear end of the heating device, and adopt a loop-type pipe layout. The pipe joints are arc-connected to reduce local losses. The width of the water-cooled pipes accounts for more than 3 / 4 of the width of the inner surface of the furnace.

[0035] The air-cooled fans are installed between the rear wall and the water-cooled pipes. They can not only promote the air flow in the furnace, prompt the hot air to discharge from the opening, but also strengthen the cooling effect of the water-cooling device.

[0036] Furthermore, the temperature measurement device is arranged in the vertical detection device layout groove of the porous wire basket to prevent the coal sample from contacting the temperature sensor and shortening the service life of the temperature sensor.

[0037] The temperature measurement device selects a single-wire multi-point NTC temperature sensor to measure the temperature of coal samples at different positions in real time.

[0038] Furthermore, the imaging device selects a high-temperature-resistant high-definition pinhole lens, which is connected to a high-definition camera. The imaging effect is excellent. The surface of the lens is made of stainless steel, and the front imaging part is protected by a quartz shield, which can adapt to a high temperature of 300 °C.

[0039] The high-definition pinhole lens is arranged inside the non-adiabatic heating furnace. The junction between the lens and the non-adiabatic heating furnace is connected by threads, and the sealing performance is good. The adjusting aperture and interface made of non-stainless steel are located outside the heating furnace, and a heat insulation pad is installed above the threads to ensure the safety of the external structure.

[0040] A steering connector is arranged below the high-definition pinhole lens to adjust the lens angle. The length of the lens can be freely selected between 100 - 700 mm, which can meet the observation requirements of different positions.

[0041] The viewing angle range of the high-definition pinhole lens is above 100°. It is arranged symmetrically along the center of the non-adiabatic heating furnace, with an interval of 90° around, and a total of four are arranged, which can meet the full-range observation of phenomena such as the coal body flame, flue gas, color, and collapse.

[0042] High-temperature optical fiber supplementary lights are arranged inside the lens to make up for the poor shooting effect caused by the dim light inside the non-adiabatic heating furnace and improve the clarity of the shooting effect.

[0043] Furthermore, the precise weighing device includes a precision electronic balance, a transparent tempered glass support platform, a transparent tempered glass shield and a fixing groove, and metal balls.

[0044] The shell of the precision electronic balance is made of metal, which can effectively shield electromagnetic interference. The internal calibration weights reduce the human measurement error. The accuracy is 0.001 g, and it is equipped with a digital display device, which can accurately and clearly observe the change in the mass of the coal body during the heating process.

[0045] The transparent tempered glass support platform is in the shape of a frustum of a pyramid and is placed on the upper part of the heating furnace. The inside of the support platform is a hollow structure. Silicone anti-slip strips are pasted on the four sides of the lower part of the support platform. A small hole is provided at the center of the top, providing a channel for connecting the electronic balance and the wire basket. The support platform can prevent the monitoring device on the upper part of the heating furnace from being pressed, provide support for placing the electronic balance, and at the same time prevent the environmental wind from disturbing the connecting wire and causing large fluctuations in the weighing indication;

[0046] The tempered glass cover covers the support platform and the electronic balance as a whole inside, preventing measurement errors caused by environmental changes or human errors. The cover is slightly wider than the non-adiabatic heating furnace to ensure comprehensive protection and is fixed on the upper part of the device by an interspersed fixing groove;

[0047] The lower part of the wire basket is connected to a metal ball, which is used to reduce the shaking of the stainless steel connecting wire caused by the change of the furnace internal environment or the structure of the coal body itself during the heating process. This device can achieve accurate weighing and reduce the fluctuation effect.

[0048] Furthermore, the gas detection device includes an automatic drainer, a gas path, and a gas detector;

[0049] The automatic drainer is composed of two U-shaped tubes connected together, filled with anhydrous CuSO4 inside, which absorbs the moisture in the air flow, reduces false peaks, and increases the accuracy of experimental measurement data. The left end is hermetically connected to the non-adiabatic heating furnace, playing a guiding role for the gas;

[0050] The gas detection device includes three gas paths: a full gas path, an oxygen gas path, and a carbon monoxide gas path. The range of the full gas path is 0 - 40000 ppm. The oxygen gas path and the carbon monoxide gas path are external gas paths. The measurement range of oxygen is 0 - 21%, and the measurement range of carbon monoxide is 0 - 10000 ppm;

[0051] The gas detector is connected to the three gas paths. There is a sample inlet and a detector at the top. Inside, there is an infrared gas detection device and a chromatographic column. The infrared gas detection device can quickly detect gases for molecules composed of different atoms such as carbon monoxide, and the chromatographic column can achieve accurate gas detection, so as to meet different functions according to different needs;

[0052] The suction device is in the shape of a funnel and is placed on one side of the wire basket to absorb the gas generated during the coal heating process at close range. A micro suction duct is arranged in the horizontal detection device layout groove inside the wire basket, which can suck the gas generated inside the coal body during the temperature rise of the coal sample into the gas detection device.

[0053] Furthermore, the waste gas treatment device includes an air inlet, a grille, an activated carbon layer, an air outlet, a feeding port, and a discharging port;

[0054] The grille has fine small holes inside, providing a channel for the experimental waste gas to diffuse upward, and preliminarily filtering the experimental waste gas. The impurities precipitate at the bottom of the device;

[0055] There is an activated carbon layer, which is honeycomb activated carbon, between the upper and lower grilles. The experimental waste gas contacts the porous activated carbon with a large surface area, and pollutants are adsorbed, thus playing a role in purification. The gas that has undergone preliminary filtration and activated carbon adsorption is discharged from the air outlet;

[0056] The feeding port and the discharging port are used for timely replacement of the activated carbon. There is a layer of moisture-proof cloth inside both the feeding port and the discharging port to prevent substances such as moisture in the air from entering.

[0057] Furthermore, the data terminal can collect the temperature, mass, image and gas information detected by the detection device;

[0058] Determine the evaluation indexes of coal spontaneous combustion characteristics according to the collected information, including but not limited to the intersection temperature (°C), maximum temperature gradient (°C / min), highest point temperature (°C), mass critical value (g), fastest weight loss point (g / min), collapse degree of coal body, color and open fire of coal body, gas evolution rate (ppm / min), gas evolution change rate per unit temperature (ppm / °C), etc., and then comprehensively judge the progress stage and tendency of coal spontaneous combustion;

[0059] Among them, the intersection temperature (°C) refers to the temperature when the temperature of the coal sample is equal to the temperature in the furnace at a certain time. This value characterizes whether the sample can get out of the control of the environment and heat up and self-ignite in the transition stage. The maximum temperature gradient (°C / min) characterizes the degree of the sample's heating rate. The highest point temperature (°C) refers to the highest temperature reached by the coal sample in the stage of out-of-control ignition. The appearance of the highest point temperature indicates that the coal sample cannot be completely out of control, which is a key index for evaluating whether the coal can spontaneously ignite;

[0060] The mass critical value (g) characterizes the state of the stable mass decline of the coal sample after the transition stage is completed. This index is the boundary for dividing out-of-control. The fastest weight loss point (g / min) refers to the point where the mass of the coal sample drops sharply in the rapid oxidation stage, characterizing the rapid pyrolysis of the coal sample;

[0061] The gas evolution rate (ppm / min) refers to the amount of gas evolved per minute, which can characterize the speed of gas evolution in different stages. The gas evolution change rate per unit temperature (ppm / °C) refers to the amount of gas released when the temperature of the coal sample rises by 1 °C, which can characterize the speed of gas evolution in different temperature stages and is used to distinguish the generation temperature of characteristic gases;

[0062] The collapse degree, color and open fire of the coal body are evaluation indexes for the out-of-control combustion in the accelerated oxidation stage of the coal body. When the coal sample is out of control and burning, characteristics such as collapse and turning red will appear on the surface of the coal body. Description of the Drawings

[0063] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0064] Figure 1 It is a schematic structural diagram of a comprehensive test device for the kinetic characteristics of spontaneous combustion oxidation of coal with programmed temperature control in an open environment;

[0065] Figure 2 It is a schematic structural diagram of a porous wire basket and sensor arrangement;

[0066] Figure 3 It is a schematic structural diagram of a rapid heating device;

[0067] Figure 4 It is a schematic structural diagram of a rapid cooling device;

[0068] Figure 5 It is a schematic diagram of the structure and arrangement of an internal camera device;

[0069] Figure 6 It is a schematic structural diagram of a precise weighing device;

[0070] Figure 7 It is a schematic structural diagram of a gas detection device;

[0071] Figure 8 It is a schematic structural diagram of an exhaust gas treatment device; Specific embodiments

[0072] The following will describe the embodiments of the present invention in detail with reference to the drawings.

[0073] As Figure 1 shown, the present invention provides a comprehensive test device for the kinetic characteristics of spontaneous combustion oxidation of coal with programmed temperature control in an open environment, including a gas supply device, a non-adiabatic heating furnace, a rapid heating / cooling device, a temperature measurement device, a camera device, a precise weighing device, a gas detection device, an exhaust gas treatment device, and a data terminal;

[0074] The gas supply device includes a gas cylinder, a pressure regulating valve, a gas mixer, an elastic airbag, and a flow meter, which can freely adjust the gas composition according to needs and stably input it into the non-adiabatic heating furnace after uniform mixing. The gas supply device is hermetically connected to the non-adiabatic heating furnace to ensure the airtightness of the device and avoid insufficient gas supply caused by gas leakage;

[0075] The non-adiabatic heating furnace is an open environment, with evenly distributed small holes around the internal wire basket. The coal sample is placed in it and directly contacts the air in the furnace to achieve non-adiabatic heating;

[0076] The rapid heating device is installed at the top, bottom and three sides of the heating furnace. It adopts a microcrystalline glass wavy heating plate to increase the heating speed of the coal sample in the non-adiabatic heating furnace.

[0077] The rapid cooling device consists of two parts: a water cooling device and an air cooling device. The water cooling pipes are arranged at the bottom and three sides of the heating furnace, and the air cooling fans are arranged at the back of the water cooling pipes on the wall opposite to the opening, which can accelerate the cooling speed of the environment in the non-adiabatic heating furnace after the experiment and improve the experimental efficiency.

[0078] The temperature measuring device is arranged in the vertical detection device arrangement groove at the center of the cylinder of the wire basket to measure the temperature of the coal sample at different positions in real time.

[0079] The camera device is built into the non-adiabatic heating furnace and is arranged in central symmetry with a 90° interval around it, which can observe phenomena such as the flame, smoke, color, and collapse of the coal body in all directions.

[0080] The precise weighing device realizes precise weighing and reduces the fluctuation effect by adding a glass shield and metal balls.

[0081] The gas detector uses an infrared gas detection device and a chromatographic column to complete gas detection, realizing rapid and accurate measurement of gas-phase products.

[0082] The waste gas treatment device is connected to the non-adiabatic heating furnace and the gas detector, and the excess gas enters the waste gas treatment device to achieve the effect of purifying the gas.

[0083] The data terminal collects the temperature, mass, image and gas information detected by the detection device, and comprehensively judges the progress stage and tendency of coal spontaneous combustion.

[0084] Figure 2 It is a schematic diagram of the structure of the porous wire basket and the sensor arrangement. The wire basket is a cylinder with a height of 10 cm and a radius of 4 cm. The lower cover is fixed and the upper cover is movable, which can adapt to the requirements of holding different sample amounts. The periphery of the circular upper cover is butyl rubber, which plays a role in sealing and sliding.

[0085] The cylinder of the wire basket is made of transparent high-temperature glass, which can withstand a high temperature of 500 °C for a long time. Circular fine holes are evenly laid on the surface, and the opening rate is equal to the porosity of the coal surface, ensuring that gas can better enter and exit the wire basket and fully contact the sample.

[0086] A vertical detection device arrangement groove is provided at the center of the porous wire basket cylinder, and three horizontal detection device arrangement grooves with a diameter of 2.5 mm are provided inside the wire basket. Circular fine holes are arranged around the detection device arrangement grooves, and the opening rate is equal to the porosity of the coal surface, preventing the detection device from affecting the coal structure. A copper ultra-thin filter screen is installed inside the detection device arrangement groove to prevent the coal particles from becoming smaller during the reaction and entering the detection device arrangement groove, shortening the service life of the detection device.

[0087] The temperature measurement device selects a single-wire multi-point NTC temperature sensor, which is arranged in the vertical detection device arrangement groove of the porous wire basket. A micro-suction duct is provided in the horizontal detection device arrangement groove, which can suck the gas generated inside the coal sample into the gas detection device during the temperature rise process of the coal sample.

[0088] Figure 3 Figure 4 is a schematic structural diagram of the rapid heating device. The rapid heating device adopts a glass-ceramic wavy heating plate, which is installed on the top, bottom and three sides of the heating furnace.

[0089] The glass-ceramic heating plate prepares a nano atomization coating on the glass-ceramic, so that the heated substance can be rapidly heated under the action of atomic resonance and infrared rays. This material has a fast heating speed, a high effective electro-thermal conversion rate and strong antioxidant ability.

[0090] The heating plate is wavy, and the wavy shape is composed of multiple parabolas. The ratio of the horizontal projection length to the vector height of the parabola is 4:3, which significantly increases the heating area.

[0091] The heating speed process of the heating plate is controlled by a programmed temperature control system. The heating range is 0 - 300 °C, and it can achieve stepped heating with an accuracy of ±1 °C.

[0092] In one example, stepped heating is adopted. The heating rate from 0 to 100 °C is 0.5 °C / min, the heating rate from 100 to 200 °C is 1.0 °C / min, and the heating rate from 200 to 300 °C is 2.0 °C / min.

[0093] Figure 4 Figure 5 is a schematic structural diagram of the rapid cooling device. The rapid cooling device includes two parts: a water cooling device and an air cooling device.

[0094] The water cooling device consists of a water pump, a radiator, a cooling fan, water cooling pipes and a flow regulating valve. After the experiment, an external water pump is used for circulating flow. The initial flow rate is set to 0.5 m / s. The water stored in the radiator flows along the water cooling pipes in the non-adiabatic heating furnace for cooling, and then flows out and is cooled by the cooling fan, and then circulates back into the non-adiabatic heating furnace. A flow regulating valve is installed on the water inlet pipe, which can adjust the water inlet flow according to the actual requirements in the furnace.

[0095] The radiator is made of stainless steel and is in a flat corrugated shape, which increases the heat dissipation area. A graphene heat dissipation film is laid on the surface of the radiator, which has a high thermal conductivity and can effectively improve the cooling speed of the circulating water.

[0096] The water cooling pipes are made of stainless steel, and a graphene heat dissipation film is laid on the surface. They are arranged on three sides and the bottom of the building, located at the rear end of the heating device, and adopt a loop-type pipe layout. The pipe joints are arc-connected to reduce local losses. The width of the water cooling pipes accounts for more than 3 / 4 of the width of the inner surface of the furnace.

[0097] The air-cooled fan is installed between the rear wall and the water-cooling pipeline, which can not only promote the air flow in the furnace, prompt the hot air to be discharged from the opening, but also enhance the cooling effect of the water-cooling device.

[0098] Figure 5 It is a schematic diagram of the structure and layout of the built-in camera device. The camera device selects a high-temperature-resistant high-definition pinhole lens, which consists of an interface, an adjustable aperture, a heat insulation pad, a thread, a stainless steel shell, a steering connector, a high-definition lens, an optical fiber fill light, and a quartz shield;

[0099] The high-definition pinhole lens is connected to the high-definition camera, and the imaging effect is excellent;

[0100] The diameter of the high-definition pinhole lens is 0.02 m. It is arranged inside the non-adiabatic heating furnace, can adapt to a high temperature of 300 °C, and is connected by a thread at the junction with the non-adiabatic heating furnace, with good sealing performance;

[0101] The adjustable aperture and interface made of non-stainless steel material are located outside the heating furnace, and a heat insulation pad is installed above the thread to ensure the safety of the external structure;

[0102] A steering connector is set at the lower part of the high-definition pinhole lens, which can adjust the lens angle. The lens length can be freely selected between 100 - 700 mm, which can meet the observation requirements of different positions. The viewing angle range of the high-definition pinhole lens is above 100°. It is arranged symmetrically along the center of the non-adiabatic heating furnace, with a 90° interval around, and a total of four are arranged, which can meet the all-round observation of phenomena such as coal body flame, smoke, color, and collapse, and measure the coal spontaneous combustion tendency;

[0103] An optical fiber fill light for high temperature is arranged inside the lens to make up for the poor shooting effect caused by dim light in the non-adiabatic heating furnace and improve the clarity of the shooting effect.

[0104] Figure 6 It is a schematic diagram of the structure of the precise weighing device, including a precision electronic balance, a transparent tempered glass support platform, a transparent tempered glass shield and a fixing groove, and a metal ball;

[0105] The shell of the precision electronic balance is made of metal material, which can effectively shield electromagnetic interference. The internal calibration weights can reduce the human measurement error. The accuracy is 0.001 g, and it is equipped with a digital display device, which can accurately and clearly observe the change of the coal body mass during the heating process;

[0106] The transparent tempered glass support platform is in the shape of a frustum of a pyramid and is placed on the upper part of the heating furnace. The thickness of the tempered glass is 6 mm, which has the characteristics of high strength, strong thermal stability and excellent safety. The inside of the support platform is a hollow structure. Silicone anti-slip strips are pasted on the four sides of the lower part of the support platform, and a small hole is provided at the center of the top, which provides a channel for the connection between the electronic balance and the wire basket. The support platform can prevent the monitoring device on the upper part of the heating furnace from being pressed, provide support for the placement of the electronic balance, and at the same time prevent the disturbance of the environmental wind to the connecting wire from causing large fluctuations in the weighing reading;

[0107] The tempered glass cover encloses the support platform and the electronic balance as a whole inside, preventing measurement errors caused by environmental changes or human errors. The cover is slightly wider than the non-adiabatic heating furnace to ensure comprehensive protection. About 15 cm of the central 1 / 3 - 1 / 2 area on the four sides of the cover extends downward and is inserted into the protruding U-shaped structure outside the heating furnace to form an interpenetrating fixing groove, fixing the cover on the upper part of the device;

[0108] The lower part of the wire basket is connected to a metal ball, which is used to reduce the shaking of the stainless steel connecting wire caused by the change of the furnace environment or the structure of the coal body itself during the heating process. This device can achieve accurate weighing and reduce the fluctuation effect.

[0109] Figure 7 It is a schematic structural diagram of a gas detection device, including an automatic drain, a gas path, and a gas detector;

[0110] The automatic drain is connected by two U-shaped tubes and contains anhydrous CuSO4 inside to absorb the moisture in the air flow, reduce false peaks, and increase the accuracy of experimental data. The left end is hermetically connected to the non-adiabatic heating furnace to play a role in guiding the gas;

[0111] The gas detection device includes three gas paths: a full gas path, an oxygen gas path, and a carbon monoxide gas path. The full gas path has a range of 0 - 40000 ppm, and the oxygen gas path and the carbon monoxide gas path are external gas paths. The oxygen measurement range is 0 - 21%, and the carbon monoxide measurement range is 0 - 10000 ppm;

[0112] The gas detector is connected to the three gas paths. There is a sample inlet and a detector at the top, and it contains an infrared gas detection device and a chromatographic column inside. The infrared gas detection device uses the different absorption degrees of different gases for infrared waves to detect the gas concentration by measuring the infrared absorption wavelength, and can quickly detect gases such as carbon monoxide composed of different atoms. The chromatographic column can achieve accurate gas detection by the different adsorption or dissolution abilities of the stationary phase for each component, so as to meet different functions according to different needs.

[0113] Figure 8 It is a schematic structural diagram of an exhaust gas treatment device, which includes an air inlet, a grille, an activated carbon layer, an air outlet, a feeding port, and a discharging port;

[0114] The grille has fine holes inside, providing a channel for the upward diffusion of experimental exhaust gas and preliminarily filtering the experimental exhaust gas. The impurities precipitate at the bottom of the device;

[0115] An activated carbon layer is placed between the upper and lower grilles. It is honeycomb activated carbon. The experimental exhaust gas contacts the porous activated carbon with a large surface area, and the pollutants are adsorbed, thus playing a role in purification. The gas that has been preliminarily filtered and adsorbed by the activated carbon is discharged from the air outlet;

[0116] The feeding port and the discharging port are used for timely replacement of activated carbon. A layer of moisture-proof cloth is provided inside both the feeding port and the discharging port to prevent substances such as moisture in the air from entering, resulting in waste of resources. The moisture-proof cloth is slightly wider than the feeding port and the feeding port by 1 cm to ensure the sealing of the device. This device can achieve a safe test environment and adsorb experimental waste gas.

[0117] In this embodiment, according to the temperature, mass, image, and gas information detected by the detection device collected by the data terminal, the coal spontaneous combustion evaluation index is determined, and then the progress stage and tendency of coal spontaneous combustion are comprehensively judged.

[0118] The temperature evaluation index includes: intersection temperature (°C), maximum temperature gradient (°C / min), and highest point temperature (°C); among them, the intersection temperature refers to the temperature when the coal sample temperature is equal to the furnace temperature at a certain time. This value characterizes whether the sample can get out of the control of the environment and start spontaneous combustion during the transition stage. The maximum temperature gradient characterizes the degree of the sample's heating rate. The highest point temperature refers to the highest temperature reached by the coal sample during the out-of-control ignition stage. The appearance of the highest point temperature indicates that the coal sample cannot be completely out of control, which is a key index for evaluating whether the coal can spontaneously ignite.

[0119] The mass evaluation index includes: mass critical value (g), fastest weight loss point (g / min); among them, the mass critical value characterizes the state of the coal sample's stable mass decline after the transition stage. This index is the boundary for dividing out-of-control. The fastest weight loss point refers to the point where the mass of the coal sample drops sharply during the rapid oxidation stage, characterizing the rapid pyrolysis of the coal sample.

[0120] The gas evaluation index includes: gas evolution rate (ppm / min), gas evolution change rate per unit temperature (ppm / °C); using the change value can exclude the influence of other gases in the heating furnace. The gas evolution rate refers to the amount of gas evolved per minute, which can characterize the speed of gas evolution in different stages. The gas evolution change rate per unit temperature refers to the amount of gas released when the temperature of the coal sample rises by 1 °C, which can characterize the speed of gas evolution in different temperature stages and is used to identify the generation temperature of characteristic gases.

[0121] The image evaluation index includes: the collapse degree, color, and open fire of the coal body; when the coal sample is burning out of control, characteristics such as collapse and turning red will appear on the surface of the coal body.

[0122] In an example, after the coal body reaches the out-of-control point, it begins to develop into deep oxidation, cracks appear and it begins to break, resulting in a cracking and collapse phenomenon. After the large-particle coal sample collapses, the coal sample cracks into smaller particles.

[0123] In one example, for low-rank coals such as lignite, the evolution rates of CO2 and CO gases are relatively small during the low-temperature oxidation stage, basically zero, the temperature change rate is relatively slow, and there is a slight upward trend in the mass of the coal body. In the transition stage, the temperature of the coal body will gradually exceed the furnace temperature and reach the crossover temperature. The gas evolution rate gradually increases, and it begins to develop towards deep oxidation. Since the moisture in the coal body starts to evaporate, the mass begins to decrease and reaches the mass critical value. In the accelerated oxidation stage, the coal body will experience out-of-control ignition, the gas evolution amount increases, the coal body turns red and shows a collapse phenomenon on the surface, and obvious black smoke appears above the coal body, resulting in a sharp drop in mass and a sharp rise in temperature. As the oxidation of the coal body gets out of control and continuously releases heat, the highest temperature is finally reached.

[0124] In one example, the spontaneous combustion tendency of a coal sample under different oxygen concentrations is set as U, and the spontaneous combustion tendency U is comprehensively determined by temperature, mass, image, and gas. When normal air supply (oxygen concentration 21%) is set, the temperature, mass, image, and gas evaluation indexes are the highest point temperature A, weight loss rate B, collapse degree C, and carbon monoxide evolution rate D respectively; the highest point temperature A under different oxygen concentrations i , weight loss rate B i , collapse degree C i , carbon monoxide evolution rate D i . The evaluation indexes for different oxygen concentrations are dimensionless, and the increase ratio of the highest point temperature a = (A i –A) / A, the increase ratio of the weight loss rate b = (B i –B) / B, the increase ratio of the collapse degree c = (C i –C) / C, and the increase ratio of the carbon monoxide evolution rate d = (D i –D) / D are determined. Importance assignments are made according to the influence degrees of the highest point temperature, weight loss rate, collapse degree, and carbon monoxide evolution rate on coal spontaneous combustion, which are the highest point temperature w, weight loss rate x, collapse degree y, and carbon monoxide evolution rate z respectively, where w + x + y + z = 1. Furthermore, the comprehensive judgment of the coal spontaneous combustion tendency U = aw + bx + cy + dz, where if the evaluation index promotes coal spontaneous combustion, it is added, and if it inhibits coal spontaneous combustion, it is subtracted.

[0125] The beneficial effects of the present invention: Combining the characteristics of the real underground environment and the adiabatic programmed temperature rise furnace, it can relatively realistically simulate different underground climate environments, achieve rapid temperature rise and fall, accurately and comprehensively measure parameters such as temperature, image, mass, and characteristic gases, and then analyze the kinetic characteristics of coal spontaneous combustion oxidation.

[0126] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. An integrated test device for the kinetic characteristics of temperature-controlled coal spontaneous combustion oxidation in an open environment, characterized in that It includes a gas supply device, a non-adiabatic heating furnace, a rapid heating / cooling device, a temperature measuring device, a camera device, a precise weighing device, a gas detection device, an exhaust gas treatment device, and a data terminal; the gas supply device is hermetically connected to the non-adiabatic heating furnace; the non-adiabatic heating furnace is an open environment, and the internal wire basket contains coal samples and is in direct contact with the air inside the non-adiabatic heating furnace; the rapid heating / cooling device is arranged along the inner wall of the non-adiabatic heating furnace, and the rapid cooling device is located at the rear end of the rapid heating device and is closer to the inner wall; the rapid heating device uses a microcrystalline glass corrugated heating plate, which is installed on the top, bottom and three sides of the non-adiabatic heating furnace. The corrugated shape of the microcrystalline glass corrugated heating plate is composed of multiple parabolas, and the ratio of the horizontal projection length to the sagitta of the parabola is 4:

3. The microcrystalline glass corrugated heating plate enables the heated substance to rapidly heat up under the action of infrared rays. The heating rate is controlled by a programmed temperature control system, and the heating range is 0-300°C with an accuracy of ±1°C; the temperature measuring device is arranged on the central axis of the wire basket to achieve multi-point detection; the camera device is evenly arranged inside the non-adiabatic heating furnace; the gas detection device uses an infrared gas detection device and a chromatographic column to complete rapid gas detection and precise gas detection; the data terminal receives and processes the detection information to determine the kinetic characteristics of coal spontaneous combustion; the exhaust gas treatment device is connected to the non-adiabatic heating furnace and the gas detection device, and the excess gas is discharged after being adsorbed by the activated carbon layer.

2. The comprehensive test device for the kinetic characteristics of coal spontaneous combustion oxidation with program temperature control in an open environment according to claim 1, characterized in that, The non-adiabatic heating furnace includes a shell and a wire basket; the top, bottom and three sides of the shell select a three-layer superposition heat preservation structure of stainless steel-insulation cotton-high temperature resistant ceramic plate, and the other side selects a double-layer high-vacuum inner cavity high temperature resistant glass; the wire basket is a cylinder, made of transparent high temperature glass, with a height of 10 cm and a radius of 4 cm. The lower cover is fixed and the upper cover is movable. Circular fine holes are evenly laid on the surface of the cylinder, and the opening rate is equal to the porosity of the coal surface; a vertical detection device arrangement groove with a diameter of 2.5 mm is provided at the center position of the cylinder, and a single-wire multi-point NTC temperature sensor can be inserted into the vertical detection device arrangement groove; three horizontal detection device arrangement grooves are provided inside the wire basket, and a micro-suction duct is provided in the horizontal detection device arrangement groove; circular fine holes are opened around the horizontal / vertical detection device arrangement groove, and the opening rate is equal to the porosity of the coal surface, and a copper ultra-thin filter screen is installed inside.

3. The comprehensive test device for the kinetic characteristics of spontaneous combustion oxidation of coal with program temperature control in an open environment according to claim 1, wherein The rapid cooling device includes two parts: a water cooling device and an air cooling device; the water cooling device consists of a water pump, a radiator, a cooling fan, a water cooling pipe and a flow regulating valve. Both the radiator and the water cooling pipe are made of stainless steel structure, and a graphene heat dissipation film is laid on the surface. The water cooling pipe is arranged on three sides and the bottom of the non-adiabatic heating furnace, located at the rear end of the rapid heating device, and adopts a loop-type pipe layout. All pipe joints are arc-connected. The width of the water cooling pipe accounts for more than 3 / 4 of the inner surface width of the non-adiabatic heating furnace; the air cooling fan is installed between the rear wall of the non-adiabatic heating furnace and the water cooling pipe.

4. The comprehensive test device for the kinetic characteristics of coal spontaneous combustion oxidation with temperature control in an open environment according to claim 1, characterized in that, The camera device selects a high-definition pinhole lens that is resistant to high temperatures and is connected to a high-definition camera. The surface of the high-definition pinhole lens is made of stainless steel, and the front camera part is protected by a quartz shield. The high-definition pinhole lens is arranged inside the non-adiabatic heating furnace and is connected to the non-adiabatic heating furnace by a threaded connection at the junction. The angle and length of the high-definition pinhole lens can be adjusted, and it is arranged symmetrically along the center of the non-adiabatic heating furnace, with a 90° interval around it, and a total of four are arranged. A high-temperature optical fiber fill light is arranged inside the high-definition pinhole lens.

5. The comprehensive test device for the kinetic characteristics of coal spontaneous combustion oxidation with temperature control in an open environment according to claim 1, wherein, The precise weighing device includes a precision electronic balance, a transparent tempered glass support platform, a transparent tempered glass shield and a fixing groove, and a metal ball. The precision of the precision electronic balance is 0.001 g, and it is equipped with a digital display device. The transparent tempered glass support platform is in the shape of a frustum and is placed on the upper part of the non-adiabatic heating furnace. It has a hollow structure inside, and there is a small hole in the center of the top, providing a channel for connecting the precision electronic balance and the wire basket. The transparent tempered glass support platform can prevent the monitoring device on the upper part of the non-adiabatic heating furnace from being pressed, provide support for placing the precision electronic balance, and at the same time prevent the disturbance of the environmental wind on the stainless steel connecting wire between the precision electronic balance and the wire basket, which may cause large fluctuations in the weighing indication. The transparent tempered glass shield covers the transparent tempered glass support platform and the precision electronic balance as a whole and is fixed on the upper part of the non-adiabatic heating furnace through the fixing groove. The lower part of the wire basket is connected to the metal ball.

6. The comprehensive test device for kinetic characteristics of spontaneous combustion oxidation of coal under program temperature control in an open environment according to claim 1, characterized in that, The gas detection device includes an automatic drain, a gas path, and a gas detector. The automatic drain is formed by connecting two U-shaped tubes, and the left end is hermetically connected to the non-adiabatic heating furnace. The gas detection device includes three gas paths, namely a full gas path, an oxygen gas path, and a carbon monoxide gas path. The oxygen gas path and the carbon monoxide gas path are external gas paths. The gas detection device is connected to the three gas paths, and there is a sampling port and a detector at the top. It contains the infrared gas detection device and the chromatographic column inside. The infrared gas detection device can quickly detect gases of molecules composed of different atoms such as carbon monoxide, and the chromatographic column can achieve precise gas detection.

7. The comprehensive test device for kinetic characteristics of spontaneous combustion oxidation of coal with temperature control in an open environment according to claim 1, characterized in that The waste gas treatment device includes an air inlet, a grille, an activated carbon layer, an air outlet, a feeding port, and a discharging port. The grille preliminarily filters the experimental waste gas. The activated carbon layer is placed between the upper and lower grilles, and the activated carbon is used to adsorb the experimental waste gas. The inside of the activated carbon layer is honeycomb activated carbon. The gas that has been preliminarily filtered and adsorbed by the activated carbon is discharged from the air outlet. The feeding port and the discharging port are used for timely replacement of the activated carbon, and there is a layer of moisture-proof cloth inside both the feeding port and the discharging port.

8. The comprehensive test device for kinetic characteristics of spontaneous combustion and oxidation of coal with temperature control in an open environment according to claim 1, characterized in that, The data terminal can collect the temperature, mass, image and gas information detected by the detection device, and determine the indexes for evaluating the characteristics of coal spontaneous combustion, including the intersection temperature (°C), the maximum temperature gradient (°C / min), the highest point temperature (°C), the mass critical value (g), the fastest weight loss point (g / min), the collapse degree of the coal body, the color and open fire of the coal body, the gas evolution rate (ppm / min), the gas evolution change rate per unit temperature (ppm / °C), etc., and assign weights to the index parameters to comprehensively judge the progress stage and tendency of coal spontaneous combustion.

9. The comprehensive test device for the kinetic characteristics of coal spontaneous combustion oxidation with program temperature control in an open environment according to claim 1, characterized in that, Combining the characteristics of the real underground environment and the adiabatic programmed temperature furnace, it can relatively truly simulate different underground environments, accurately and comprehensively measure parameters such as temperature, image, mass, and characteristic gas, and then analyze the kinetic characteristics of coal spontaneous combustion.

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