CN108982745A - Coal sample combustion characteristics test device under varying strength jet flame heat radiation - Google Patents

Abstract

The present invention relates to coal sample combustion characteristics test devices under a kind of varying strength jet flame heat radiation, can probe into contactless flame to the situation of igniting of coal sample by this device.The experimental provision includes cabinet, flame heating component, coal sample placing modules and detection components；Cabinet is equipped with experiment porch, gas port, smoke discharging pipe；Flame heating component includes fuel tank and Bunsen burner, and Bunsen burner is connect with fuel tank by conduit；Coal sample placing modules include telescopic rod, strut, track and planchet；Track is arranged on experiment porch, and telescopic rod is arranged on experiment porch；Strut is provided on telescopic rod, strut end is placed with planchet；Detection components are arranged in cabinet, including mass sensor, photoelectricity thermocouple, radiation heatflowmeter, gas sensor and camera；The end of strut is arranged in mass sensor, and photoelectricity thermocouple, radiation heatflowmeter, gas sensor are arranged on strut, and camera is arranged above cabinet.

Description

Measuring device for combustion characteristics of coal samples under thermal radiation of jet flames with different intensities

technical field

The invention relates to the field of coal combustion experiment devices, in particular to a device for testing the combustion characteristics of coal samples under the thermal radiation of jet flames with different intensities.

Background technique

Mine fire is a serious mine disaster accident, which causes a lot of waste of resources and loss of personnel and property every year. Among the coal combustion accidents in mines, the accidents of directly or indirectly igniting coal due to gas combustion account for a relatively large proportion. In a large number of coal mine gas and coal spontaneous combustion fires, the coal sample was not directly in contact with the flame produced by the gas, and the temperature in the area did not reach the ignition point of the coal, but the coal was still ignited. The flame produced by gas combustion is basically similar to the jet fire under laboratory conditions. Therefore, exploring the influence factors of jet fire intensity on coal ignition and the changes of various parameters of coal samples during the heating process are very important for exploring the relationship between underground gas and coal. Coupled combustion is of great significance.

Jet fire is one of the basic types of diffusion flames, and it is also the most common form of expression in the process of flame propagation. It is specifically the combustion phenomenon produced by the ignition source after the combustible gas is mixed with air. If the flow rate of the combustible gas is lower than the critical value, the gas flow is in a laminar flow state, and the mixing of the combustible gas and air occurs in the thin flame surface in the form of molecular diffusion, and the space on the flame surface is fixed, which is a jet flame. . After the gas is burned, the flame produces a certain amount of heat radiation. Although the outer flame of the flame is not in direct contact with the coal, the heat radiation generated by it may still cause coal combustion. The heat radiation provided by flames of different intensities is different. The thermal radiation received is also different, so the combustion conditions of coal are also different. By detecting the changes in the characteristic parameters of coal samples during this process, the heating conditions of coal samples can be reversely estimated.

At present, the methods and devices for monitoring the influencing factors of coal sample combustion mainly focus on coal spontaneous combustion and the influence of external temperature and gas on coal combustion, and rarely involve the non-contact thermal radiation to explore the ignition of coal samples.

Contents of the invention

The purpose of the present invention is to explore the ignition of coal samples by non-contact flames, so as to provide a test device for the combustion characteristics of coal samples under the thermal radiation of jet flames with different intensities.

Technical scheme of the present invention is:

A device for testing the combustion characteristics of coal samples under the heat radiation of jet flames of different intensities, including a box body, a flame heating component, a coal sample placement component and a detection component; There is a smoke exhaust pipe; the flame heating assembly includes a fuel tank and a Bunsen burner, the fuel tank is arranged outside the box, the Bunsen burner is arranged in the box, and is connected with the fuel tank through a conduit, the Bunsen burner The flame outlet of the lamp is provided with a flame shape control device; the coal sample placement assembly is arranged in the box, including telescopic rods, poles, tracks and sample dishes; the rails are set on the experimental platform, and the telescopic rods are set On the experimental platform, and move on the experimental platform through the track; the telescopic rod is provided with a pole, and the end of the pole is placed with a sample dish; the detection component is arranged in the box, including a mass sensor, a photoelectric thermocouple, radiant heat flow meter, gas sensor and camera; the mass sensor is arranged at the end of the pole, and is arranged at the lower end of the sample dish, and the photoelectric thermocouple, radiant heat flow meter, and gas sensor are all arranged on the pole, and the The camera is arranged on the top of the box.

Further, in order to effectively prevent the flame from spreading to the fuel tank, a flame arrester is provided on the conduit, and at the same time, a flow switch is provided at the outlet of the fuel tank, which can adjust the size of the flame and change the heat radiation received by the coal sample. strength.

Further, the surface of the telescopic rod, the support rod and the sample dish is coated with a heat-resistant coating, which can effectively reduce the heat conduction generated by the flame, reduce the temperature, and prevent thermal damage that may be caused by direct contact.

Furthermore, the top of the box is in the shape of a pyramid, which can gather the smoke to a greater extent.

Furthermore, the box is made of quartz glass, which is convenient for observing the progress of the experiment; one side of the left side panel of the box is hinged with the front side panel to realize the opening and closing of the left side panel.

Further, in order to speed up the smoke exhaust, a fan is installed in the smoke exhaust pipe.

Further, the conduit is a rubber conduit.

Further, the telescopic rod is provided with a sleeve rod to adjust the length of the telescopic rod.

Further, the track is provided with marked scale lines, which can accurately adjust the distance and change the intensity of thermal radiation received by the coal sample.

Further, the opening of the smoke exhaust pipe is located above the jet flame.

Compared with the prior art, the present invention has the following technical effects:

1. The present invention ignites coal samples through flame heat radiation, detects changes in coal sample temperature, properties, gas products and other data during the process, establishes a multi-field coupling model in mines, and explores the critical conditions for gas combustion flames to ignite coal seams , to study the coupling disaster mechanism of gas combustion thermal radiation and coal spontaneous combustion, which has application value for exploring the combined combustion disasters of coal mine gas and coal.

2. How the gas flame ignites the coal seam when it is not in contact with coal, the critical conditions for igniting the coal seam by flame heat radiation, the change of the physical properties of the coal sample during the process, the chemical reaction and its gas products can be obtained through the device of the present invention In order to establish the mine gas fire flame model, it provides the basis for the development conditions and effective identification information of coal spontaneous combustion thermal power disasters caused by gas, and provides accurate identification and evaluation for the occurrence and development of disasters in the future, so as to reduce the injuries of rescuers. , Improving the safety and efficiency of disaster relief provides a certain theoretical basis.

3. The present invention provides a coal sample combustion characteristic testing device based on different intensities of jet flame heat radiation, the purpose of which is to explore the ignition of coal by different intensities of jet flame heat radiation, and can accurately measure the thermal radiation change characteristics of coal samples, The characteristic temperature point of coal combustion, the real-time change characteristics of apparent characteristics, the change characteristics of the symbol gas CO with time and temperature, etc. The device can measure the ignition of coal samples by different intensities of jet fiery radiation, and can realize accurate measurement of temperature, heat radiation, quality, etc., with simple structure, convenient operation and low cost.

4. The overall structure of the test device provided by the present invention is simple, the material cost is low, the operation is stable, the measurement accuracy is high, and the measurement data is relatively comprehensive. .

5. The present invention adopts Bunsen burner to provide jet fire, the flame temperature is high, stable and less polluted. By controlling the flame intensity and changing the distance between the coal sample and the flame to control the flame intensity received by the coal sample, more accurate quantification can be achieved.

6. Each sensor of the present invention adopts non-contact measurement, which has high precision, stable performance and long service life.

Description of drawings

Fig. 1 is the structural diagram of the coal sample combustion characteristics testing device under the different intensity jet flame heat radiation of the present invention;

Fig. 2 is the front view of the test device for coal sample combustion characteristics under different intensity jet flame heat radiation of the present invention;

Fig. 3 is a partial structural diagram of the coal sample combustion characteristic testing device under different intensity jet flame heat radiation of the present invention;

Fig. 4 schematic diagram of flame shape control device 1 of the present invention;

Fig. 5 is the second schematic diagram of the flame shape control device of the present invention;

Figure 6 is the third schematic diagram of the flame shape control device of the present invention.

Reference signs: 1-fuel tank, 2-flame arrester, 3-duct, 4-experiment platform, 5-set rod, 6-telescopic rod, 7-sample dish, 8-exhaust pipe, 9-fan, 10 -camera, 11-photoelectric thermocouple, 12-gas sensor, 13-radiant heat flow meter, 14-air guide hole, 15-track, 16-bunsen burner, 17-mass sensor, 18-rod, 19-flow switch, 20-box body, 21-flame shape control device.

Detailed ways

Below in conjunction with accompanying drawing and specific embodiment the content of the present invention is described in further detail:

The invention discloses a test device for coal sample combustion characteristics based on jet flame heat radiation of different intensities. The characteristic temperature point of combustion, the real-time change characteristics of apparent characteristics, the change characteristics of the symbol gas CO with time and temperature, etc. The device can measure the ignition of coal samples by different intensities of jet fiery radiation, and can realize accurate measurement of temperature, heat radiation, quality, etc., with simple structure, convenient operation and low cost.

As shown in Figures 1 to 3, the device of the present invention is mainly composed of a box body 20, a flame heating component, a coal sample placement component and a detection component. The flame heating component mainly provides the jet flame, and the flame intensity can be controlled through the valve (flow switch 19); the coal sample placement component mainly places the experimental coal sample, and adjusts the distance between the coal sample and the flame; the detection component mainly detects the coal sample burning various parameters in the process.

The box body 20 is made of quartz glass with a thickness not less than 10mm, which has the characteristics of high strength, high hardness, high temperature resistance, high safety performance, etc., and can well observe the overall process of the experiment. The box body 20 is in an airtight state as a whole, an experiment platform 4 is arranged at the bottom, and a plurality of air guide holes 14 are arranged at the side. The box body 20 is completely closed except for the air guide hole 14, so that the experiment interference is minimized. One side of the left side panel of the box body 20 is hinged with the front side panel of the box body 20 to realize the opening and closing of the left side panel. Silicone sealing strips are provided at the joints of the remaining three sides of the left side panel and the box body to ensure the safety of the box body. tightness. The upper part of the box body 20 is in the shape of a pyramid, which gathers the smoke to a greater extent. A smoke exhaust pipe 8 is arranged at the upper end of the box body 20, and the smoke exhaust pipe 8 is connected to a fume exhaust cabinet or outdoors to lead out the smoke to prevent the smoke from interfering with the experimental results. The opening of the smoke exhaust pipe 8 is preferably located above the jet flame, which can exhaust the gas generated during the combustion of the coal sample to the greatest extent and reduce the interference of the experiment. For speeding up the smoke exhaust speed, the inside of the smoke exhaust pipe 8 is provided with a fan 9, the material of the fan 9 is a high temperature resistant metal material or other suitable materials, and the fan 9 is an explosion-proof fan.

The flame heating assembly includes a fuel tank 1 and a Bunsen burner 16 . The fuel tank 1 is arranged outside the box body 20, and the Bunsen burner 16 is fixedly placed on the experimental platform 4 made of aluminum alloy, and the Bunsen burner 16 is connected with the fuel tank 1 through a rubber conduit 3. The fuel tank 1 is equipped with high-pressure liquefied butane, and the connection between the tank body and the conduit 3 is provided with an air pressure valve (contained in the fuel tank itself) to detect the air pressure, and a control valve (the outlet of the fuel tank is also provided with a valve equipped with a breeze flow meter) Flow switch 19) controls the size of the gas supply. The Bunsen burner 16 provides a stable flame, and the combustible gas is connected to the Bunsen burner 16 through the conduit 3, and is ignited after being evenly mixed with the air. The flame temperature provided by the Bunsen burner 16 is relatively high, and the pollution is small. The flame intensity of the Bunsen burner 16 can be changed to achieve the purpose of providing different heat radiation intensities. A flame shape control device 21 is provided at the flame outlet of the Bunsen burner 16, which can change the shape of the outlet flame to achieve the purpose of simulating the gas flame under different conditions in the underground. The flame shape control device 21 is fixed on the opening by threads, and the openings have the same cross-sectional area. Any one of different shapes such as circle, rectangle, star, cross, etc. or a combination of more than one shape. As shown in Figures 4 to 6, there are flame shape control devices 21 of different standards, which can change the shape of the flame sprayed out. The device can be disassembled freely and has different standards, which can meet the simulation conditions of flames under different experimental conditions. A small flame arrester 2 is placed in the middle of the conduit 3, which can effectively prevent the flame from spreading to the fuel tank 1. The flame arrester 2 is connected by a flange, and the interface is sealed with a suitable size rubber gasket, which has good sealing performance and is easy to disassemble. The selected fuel tank 1 is a seamless high-pressure gas cylinder; the fuel is methane or other suitable fuels, which can simulate the disaster caused by the combined spontaneous combustion of gas and coal to the greatest extent; the conduit 3 is a dense rubber tube or other suitable materials, with tightness and bending resistance Good folding ability.

The coal sample placement assembly is arranged in the box body 20, including the telescopic rod 6, the support rod 18, the track 15 and the sample dish 7; the track 15 is arranged on the experimental platform 4, and the telescopic rod 6 is also arranged on the experimental platform 4. The track 15 moves on the experimental platform 4, and the track 15 is marked with a scale line, and the distance between the telescopic rod 6 and the Bunsen burner 16 can be adjusted. The telescopic rod 6 is provided with a sleeve rod 5 for adjusting height, and the sleeve rod 5 can adjust the height of the telescopic rod 6 by threads. The support rod 18 is fixedly arranged on the telescopic rod 6 and can move up and down, left and right along with the telescopic rod 6 . A sample dish 7 is placed at the end of the pole 18, and the sample dish 7 is detachable and easy to clean. The sample dish 7 is a coal sample container. The selected sample dish 7 is made of silicon carbide or other suitable materials. It is resistant to high temperature calcination, has stable physical and chemical properties, and has good thermal conductivity. The sample dish 7 can be disassembled and installed for easy cleaning. The telescopic rod 6 can move up and down vertically, which is convenient for adjusting the distance between the telescopic rod 6 and the flame; the telescopic rod 6 is clamped on the track 15, which can realize horizontal movement, and the precise scale is marked on the sliding track 15, which can measure the flame The horizontal distance from the coal sample.

The detection component is mainly composed of a mass sensor 17 , a photoelectric thermocouple 11 , a radiant heat flow meter 13 , a gas sensor 12 (CO detector) and a high-speed camera 10 . The quality sensor 17 quantitatively detects the quality of the coal sample and the quality change during the heating process, the radiation heat flow meter 13 detects the change of thermal radiation during the heating process, the photoelectric thermocouple 11 detects the temperature change of the coal sample during the heating process, and the CO detector detects the coal sample The CO concentration produced during the heating process is used to judge the progress of the oxidation process of the coal sample, and the change of the physical properties of the coal sample during the heating process is monitored by the high-speed camera 10 . Among them, the mass sensor 17, the photoelectric thermocouple 11, the radiant heat flow meter 13, and the CO detector are all installed on the support rod 18, and the specific installation positions are: the mass sensor 17 is arranged at the end of the support rod 18, and is arranged on the sample dish 7 the lower end. At a certain distance directly above the sample dish 7, a CO sensor is arranged to detect the gas change during the coal sample oxidation process; a photoelectric thermocouple 11 is arranged on the left side of the CO sensor to detect the temperature change during the coal sample oxidation process. A radiant heat flow meter 13 is arranged above the sample dish 7 to detect the thermal radiation suffered by the coal sample.

The high-speed camera 10 is set on the top of the box 20, and the high-speed camera 10 is used to capture the change of properties and the instantaneous flame during the oxidative combustion of the coal sample. The high-speed camera 10 is located obliquely above the coal sample, with a wide field of vision, and can accurately monitor the coal sample combustion process. The selected camera is a high-speed camera 10, which can accurately photograph the behavior change of the coal sample at the moment of combustion, and understand the direct process of coal combustion. The mass sensor 17 is a high-precision measuring balance, which can accurately measure the quality change of the coal sample during combustion and output data stably.

The photoelectric thermocouple 11 is located on the upper part of the coal sample, and detects the temperature change of the coal sample during the heating process. The photoelectric thermocouple 11 uses a new type of high-temperature sensor based on the theory of black body radiation. It is composed of a detection tube and a detector. It adopts a non-contact measurement method, which is resistant to high temperature and corrosion, and can effectively detect the temperature during the heating process. Changes, high precision, long service life.

The radiant heat flow meter 13 is located above the coal sample, and detects the heat radiation intensity during the heating process of the coal sample, so as to judge the flame intensity. The radiant heat flow meter 13 is an instrument used to measure heat flow. It measures the radiant heat flux density and surface temperature on the surface of the object to be measured in a non-contact manner. It has high precision, accurate measurement, long service life, wide application range, non-contact, etc. advantage.

The circuit of the detection component is erected in a high-temperature resistant non-combustible material tube to prevent circuit damage caused by high temperature. Experiment bench, expansion rod 6 and support rod 18 etc. are aluminum alloy material or other suitable materials, and quality is lighter, and hardness is high, is difficult for oxidative damage. Sliding track 15 is marked with accurate scale, can realize the quantitative movement of coal sample. The non-heat-conducting surfaces of the telescopic rod 6, the support rod 18 and the sample dish 7 are all coated with a heat-resistant coating of phosphate aluminum powder not less than 8mm, which can effectively reduce the heat conduction generated by the flame, reduce the temperature, and prevent direct contact. Thermal damage (heat-resistant coatings can also be other heat-resistant coatings). All parts of the experimental device have good heat insulation performance, and the inner walls of the cavities of each part and the joints of each part are smooth.

In the device of the present invention, the box body 20 is made of quartz glass and has a size of 50 cm x 50 cm x 50 cubes; the height of the Bunsen burner 16 is about 15--25 cm, and the flame height is between 1-5 cm. The Bunsen burner 16 is fixed at the center of the experimental platform 4, the length of the telescopic rod 6 is adapted to the height of the Bunsen burner 16, and the coal sample is basically kept at the same height as the flame; the sample dish 7 is made of quartz glass or other high temperature resistant materials, and the edge It is slightly raised and can be stably placed on the quality sensor 17. CO sensor, photoelectric thermocouple 11, radiant heat flow meter 13, camera 10 and other detection and monitoring devices are placed in appropriate positions to ensure the stability and accuracy of the detection results.

When in use, check whether the pressure gauge at the outlet of the fuel tank 1 is normal, and slowly open the gas outlet valve of the fuel tank 1 after there is no fault, so that the fuel flows into the Bunsen burner 16 through the conduit 3, and inside the Bunsen burner 16, the air flow field causes pressure fluctuations Change, the external air is sucked in, mixed evenly with combustible gas, ejected from the mouth of the Bunsen burner 16, lit the Bunsen burner 16 with an igniter, and adjusted the on-off valve of the fuel tank 1 to adjust a suitable flame size.

There are movable devices between the 4 parts of the experimental platform of the device and the box body 20, the telescopic rod 6 and the sliding track 15, the pole 18 and the sample dish 7. The left side of the box body 20 is the box door. After opening, the test platform can be pulled out from the side, and the telescopic rod 6 and the test dish can be taken off from the sliding track 15. Coal samples are filled in the test dish, placed on the quality sensor 17, and the The experimental platform 4 is pushed into the box body 20; the vertical movement of the coal sample is realized through the thread between the telescopic rod 6 and the sleeve rod 5, and the horizontal movement between the coal sample and the flame is realized by sliding the telescopic rod 6 on the slide track 15, and the slide track 15 There are precise scale marks on it to adjust the horizontal distance between the coal sample and the flame.

A load cell is connected to the end of the support rod 18 to measure the quality of the coal sample, and in the process of heating up, the quality change of the coal sample oxidized and burned can be accurately measured by the load cell to obtain the law of quality change; A radiation heat flow meter 13 is placed at 18 to detect the thermal radiation intensity of the jet flame to obtain the most intuitive and accurate data of the flame intensity; a photoelectric thermocouple 11 is arranged at the support rod 18 above the coal sample to detect the temperature change of the coal sample during the heating process , to obtain the change law of the coal sample temperature under different flame intensities; place a CO detector at a suitable position directly above the coal sample to detect the gas concentration change during the heating process of the coal sample, and monitor the oxidative combustion process of the coal sample. A high-speed camera 10 is placed at the rear upper corner of the casing 20 to photograph changes in the physical properties of the coal sample during heating, to photograph changes in the moment of coal ignition and to produce flames. Each sensor is arranged inside the box body 20, and the circuit is connected to an external display or other data storage device through the board shell of the box body 20, and the opening of the circuit is sealed with gel.

Claims (10)

1. A test device for coal sample combustion characteristics under jet flame heat radiation of different intensities, characterized in that: it includes a box body (20), a flame heating assembly, a coal sample placement assembly and a detection assembly; The bottom of the box (20) is provided with an experimental platform (4), the side is provided with an air guide hole (14), and the top is provided with a smoke exhaust duct (8); The flame heating assembly includes a fuel tank (1) and a Bunsen burner (16), the fuel tank (1) is arranged outside the box body (20), and the Bunsen burner (16) is arranged on the box body (20) and is connected with the fuel tank (1) through a conduit (3), and a flame shape control device (21) is provided at the flame outlet of the Bunsen burner (16); The coal sample placement assembly is arranged in the box body (20), including a telescopic rod (6), a pole (18), a track (15) and a sample dish (7); the track (15) is arranged on the experimental platform (4), the telescopic rod (6) is arranged on the experimental platform (4), and can move on the experimental platform (4) by the track (15); the telescopic rod (6) is provided with a pole ( 18), the end of the pole (18) is placed with a sample dish (7); The detection assembly is arranged in the casing (20), including a quality sensor (17), a photoelectric thermocouple (11), a radiant heat flow meter (13), a gas sensor (12) and a camera (10); the quality sensor ( 17) It is arranged on the end of the pole (18), and is arranged on the lower end of the sample dish (7), and the photoelectric thermocouple (11), radiant heat flow meter (13), and gas sensor (12) are all arranged on the pole (18), the camera (10) is arranged on the top of the box (20). 2. according to claim 1 said different intensity jet flame thermal radiation coal sample combustion characteristics testing device, it is characterized in that: said conduit (3) is also provided with flame arrester (2), and the outlet of said fuel tank is also equipped with A flow switch (19) is provided. 3. according to claim 2 said different intensity jet flame thermal radiation coal sample combustion characteristics testing device, it is characterized in that: the surface of described expansion rod (6), pole (18) and sample dish (7) is coated with Heat resistant coating. 4. According to claim 1, 2 or 3, the device for testing the combustion characteristics of coal samples under the heat radiation of jet flames with different intensities is characterized in that: the top end of the box (20) is in the shape of a pyramid. 5. according to claim 4 different intensity jet flame thermal radiation coal sample combustion characteristics testing device, it is characterized in that: described casing (20) adopts quartz glass to make, and one side of casing (20) left side plate and The front side panel is hinged to realize the opening and closing of the left side panel. 6 . The device for testing combustion characteristics of coal samples under jet flame heat radiation with different intensities according to claim 5 , wherein a fan ( 9 ) is arranged in the exhaust pipe ( 8 ). 7. The device for testing combustion characteristics of coal samples under jet flame heat radiation with different intensities according to claim 6, characterized in that: the conduit (3) is a rubber conduit. 8. According to claim 7, the coal sample combustion characteristic testing device under different intensity jet flame heat radiation is characterized in that: the telescopic rod (6) is provided with a sleeve rod (5), and the sleeve rod (5) adjusts the telescopic rod (6) Length. 9. The device for testing combustion characteristics of coal samples under jet flame heat radiation with different intensities according to claim 8, characterized in that: the track (15) is provided with marked scale lines. 10. The device for testing combustion characteristics of coal samples under thermal radiation of jet flames of different intensities according to claim 9, characterized in that: the opening of the exhaust pipe (8) is located above the jet flame.