Early warning methods and systems for spontaneous combustion of coal seams during the recovery period of longwall mining faces

Abstract

This invention provides a method and system for early warning of spontaneous combustion in coal seams during the recovery of longwall mining faces, relating to the field of coal seam monitoring technology. The method includes: setting up temperature sensors and gas composition sensors to acquire first temperature data and first gas composition data within the goaf, and second temperature data and second gas composition data of the longwall mining face; determining a goaf spontaneous combustion early warning coefficient based on the first temperature data and first gas composition data; determining a longwall mining face spontaneous combustion early warning coefficient based on the first gas composition data, second temperature data, and second gas composition data, thereby determining early warning information and implementing combustion prevention measures. According to this invention, as the data acquisition process progresses, data from the goaf and longwall mining face can be continuously collected for comprehensive monitoring. Furthermore, the first and second gas composition data can be compared to identify environmental hazards at the longwall mining face, improving the accuracy and comprehensiveness of monitoring.

Description

Technical Field

[0001] This invention relates to the field of coal seam monitoring technology, and in particular to a method and system for early warning of spontaneous combustion of coal seams during the recovery period of a longwall mining face. Background Technology

[0002] In related technologies, CN118887770A relates to the field of sensor technology and discloses a coal mine underground fire early warning device, including: a multi-parameter sensor body, a hook, and a suspension mechanism. The hook is used to fix the device at a preset monitoring position underground. The suspension mechanism is connected to the multi-parameter sensor body and is used to connect to the hook. The multi-parameter sensor body is internally equipped with a parameter acquisition module, an integrated data processing and decision-making module, a data transmission module, and a power supply module. The parameter acquisition module is used to collect data of relevant parameters required underground and transmit the collected data to the integrated data processing and decision-making module. This invention integrates traditional early warning, control, and some transmission functions into one module by setting up an integrated data processing and decision-making module. This reduces the number of hardware components and connection complexity of the system, lowers the system maintenance cost, and simplifies the system structure.

[0003] CN119339496A discloses a fire early warning system and method for coal mine goaf areas. The system includes: multiple wireless sensor terminals respectively installed at multiple target test environment points, at least one core communication node, and a cloud platform. The core communication node is wirelessly connected to both the multiple wireless sensor terminals and the cloud platform. The core communication node sends timed wake-up commands to the wireless sensor terminals. Based on the timed wake-up commands, the multiple wireless sensor terminals acquire environmental information related to the target test environment points and upload this information to the core communication node using a comb network communication method. The core communication node also uploads the environmental information to the cloud platform. The cloud platform provides fire early warning for coal mine goaf areas based on the environmental information. This solution addresses the problems of harsh coal mine goaf environments, difficulties in wiring wired sensors, difficulties in transmitting early warning signals, and low power consumption of the equipment.

[0004] Therefore, while the relevant technologies can monitor coal seams through sensors and issue alarms when fire hazards occur, they are difficult to comprehensively monitor the longwall face and goaf, and cannot compare the environment of the longwall face and goaf to determine environmental hazards in the longwall face.

[0005] The information disclosed in the background section of this application is intended only to enhance the understanding of the general background of this application and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0006] This invention provides a method and system for early warning of spontaneous combustion of coal seams during the recovery of longwall mining faces. It can solve the technical problems that related technologies are unable to comprehensively monitor longwall mining faces and goaf areas, and are unable to compare the environments of longwall mining faces and goaf areas to determine environmental hazards in longwall mining faces.

[0007] According to a first aspect of the present invention, a method for early warning of spontaneous combustion of coal seams during the recovery period of a longwall mining face is provided, comprising:

[0008] Temperature sensors and gas composition sensors are evenly installed along the coal mining direction in the roadway of the longwall face.

[0009] During the coal mining process, as the mining process proceeds, the first temperature data is obtained through the temperature sensor in the formed goaf, and the first gas composition data is obtained through the gas composition sensor in the goaf.

[0010] During the coal mining process, second temperature data is obtained through temperature sensors in the roadways of the longwall face, and second gas composition data is obtained through gas composition sensors in the roadways of the longwall face.

[0011] Based on the first temperature data and the first gas composition data, determine the early warning coefficient for goaf ignition.

[0012] Based on the first gas composition data, the second temperature data, and the second gas composition data, determine the fire warning coefficient for the longwall mining face;

[0013] The warning information is determined based on the fire warning coefficient of the goaf and the fire warning coefficient of the longwall face;

[0014] Based on the aforementioned warning information, determine the corresponding fire prevention measures;

[0015] Implement fire prevention measures corresponding to the aforementioned warning information.

[0016] According to a second aspect of the present invention, a coal seam spontaneous combustion early warning system is provided during the recovery of a longwall mining face, comprising:

[0017] The module is used to uniformly set temperature sensors and gas composition sensors along the coal collection direction in the roadway of the longwall mining face.

[0018] The first acquisition module is used to acquire first temperature data through a temperature sensor in the goaf and first gas composition data through a gas composition sensor in the goaf during the coal mining process.

[0019] The second acquisition module is used to acquire second temperature data through a temperature sensor in the roadway of the longwall mining face during the coal mining process, and to acquire second gas composition data through a gas composition sensor in the roadway of the longwall mining face.

[0020] The goaf ignition early warning coefficient module is used to determine the goaf ignition early warning coefficient based on the first temperature data and the first gas composition data.

[0021] The longwall face ignition early warning coefficient module is used to determine the longwall face ignition early warning coefficient based on the first gas composition data, the second temperature data, and the second gas composition data.

[0022] The early warning information module is used to determine early warning information based on the fire warning coefficient of the goaf and the fire warning coefficient of the longwall face.

[0023] The fire prevention measures module is used to determine the corresponding fire prevention measures based on the warning information.

[0024] The implementation module is used to implement the fire prevention measures corresponding to the warning information.

[0025] By adopting the above technical solution, the present invention can achieve the following technical effects:

[0026] According to this invention, temperature sensors and gas composition sensors can be installed along the coal mining direction to continuously collect data from the goaf and the longwall face as the mining process progresses. This allows for comprehensive monitoring of the goaf and longwall face. Furthermore, comparing the first gas composition data of the goaf with the second gas composition data of the longwall face can identify environmental hazards at the longwall face, improving the accuracy and comprehensiveness of monitoring. When determining the goaf ignition warning coefficient, the distance between the current and previous detection times and the critical position can be used to perform a longitudinal comparison of the current temperature and oxygen content data with those of the previous detection time. A reference value can also be set based on the distance between the sensor array and the critical position, allowing for a lateral analysis of the current temperature and oxygen content data to obtain temperature-based and oxygen content-based ignition risk coefficients. Multiplying these two coefficients yields the overall ignition risk coefficient, enabling the analysis of multiple factors contributing to ignition risk and improving the comprehensiveness and accuracy of goaf ignition analysis. When determining the ignition risk coefficient of a longwall face, a temperature-based ignition risk coefficient can be determined by longitudinally comparing the second temperature data at the current and previous detection times, and by comparing the current second temperature data with a preset temperature threshold. Alternatively, a quantity-based ignition risk coefficient can be determined by the number of locations with ignition risk, thus obtaining the longwall face ignition risk coefficient and improving the comprehensiveness and accuracy of longwall face ignition risk monitoring. When determining the environmental risk coefficient of a longwall face, a combustible gas concentration-based environmental risk coefficient can be determined by comparing the combustible gas concentrations in the goaf and the longwall face, and by the relative change in combustible gas concentration at the longwall face. Furthermore, the time required for the location with the highest temperature to reach the ignition temperature under the condition of maximum change can be determined, thus determining the temperature-based environmental risk coefficient. Therefore, obtaining the longwall face environmental risk coefficient based on both combustible gas concentration-based and temperature-based environmental risk coefficients allows for an accurate description of environmental hazards at the longwall face, improving the accuracy and comprehensiveness of environmental risk description.

[0027] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only, and are not intended to limit the invention. Other features and aspects of the invention will become clearer from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other embodiments can be obtained based on these drawings without creative effort.

[0029] Figure 1 An exemplary flowchart illustrates a method for early warning of spontaneous combustion of coal seams during the recovery of a longwall face according to an embodiment of the present invention.

[0030] Figure 2 A block diagram of an early warning system for spontaneous combustion of coal seams during the recovery of a longwall face according to an embodiment of the present invention is shown as an example. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] The technical solution of the present invention will be described in detail below with reference to specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments.

[0033] Figure 1 An exemplary flowchart illustrates a method for early warning of spontaneous combustion of coal seams during the recovery period of a longwall face according to an embodiment of the present invention. The method includes:

[0034] Step S101: Temperature sensors and gas composition sensors are evenly installed in the roadway of the longwall face along the coal collection direction.

[0035] Step S102: During the coal mining process, as the mining process proceeds, the first temperature data is obtained through the temperature sensor in the formed goaf, and the first gas composition data is obtained through the gas composition sensor in the goaf.

[0036] Step S103: During the coal mining process, second temperature data is obtained through a temperature sensor in the roadway of the mining face, and second gas composition data is obtained through a gas composition sensor in the roadway of the mining face.

[0037] Step S104: Determine the goaf ignition warning coefficient based on the first temperature data and the first gas composition data;

[0038] Step S105: Determine the fire warning coefficient of the longwall face based on the first gas composition data, the second temperature data, and the second gas composition data;

[0039] Step S106: Determine the early warning information based on the goaf ignition early warning coefficient and the longwall face ignition early warning coefficient;

[0040] Step S107: Determine the corresponding fire prevention measures based on the warning information;

[0041] Step S108: Implement fire prevention measures corresponding to the warning information.

[0042] According to an embodiment of the present invention, the method for early warning of spontaneous combustion of coal seams during the recovery of the longwall face can set temperature sensors and gas composition sensors in the coal collection direction, and continuously collect data from the goaf and the longwall face as the collection process proceeds, thereby comprehensively monitoring the goaf and the longwall face. It can also compare the first gas composition data of the goaf with the second gas composition data of the longwall face to determine environmental hazards at the longwall face, thereby improving the accuracy and comprehensiveness of monitoring.

[0043] According to one embodiment of the present invention, in step S101, during the coal collection process at the longwall face, the collection direction is from the inside out, that is, from the depth of the roadway to the shallower part of the roadway. As the collection process proceeds, the area on the longwall face that has been collected forms a goaf. Every time a goaf is formed at a certain distance, it must be isolated from the unmined longwall face. When setting up temperature sensors and gas composition sensors, they can be set together to form a sensor group, and the distance between the sensor groups is equal to the aforementioned isolation distance. Temperature data and gas composition data can be acquired once each time isolation is performed.

[0044] According to one embodiment of the present invention, in step S102, the sequence number of the sensor group can increase sequentially from the depth of the roadway to the shallowest point. As the data acquisition process proceeds, the goaf gradually increases, and the unmined longwall face gradually decreases. Therefore, the number of sensor groups in the goaf gradually increases, and the number of sensor groups in the unmined longwall face gradually decreases. As the mining process proceeds, the number of first temperature data and first gas composition data acquired each time is one more than the number of first temperature data and first gas composition data acquired in the previous time.

[0045] According to one embodiment of the present invention, in step S103, similarly, as the mining process proceeds, the number of second temperature data and second gas composition data acquired each time is one less than the number of second temperature data and second gas composition data acquired in the previous time.

[0046] According to one embodiment of the present invention, in step S104, the goaf fire early warning coefficient can be used to describe the risk of goaf fire.

[0047] According to one embodiment of the present invention, determining the goaf ignition warning coefficient based on the first temperature data and the first gas composition data includes: acquiring first temperature data from n temperature sensors and first gas composition data from n gas composition sensors at the current detection time; acquiring first temperature data from n-1 temperature sensors and first gas composition data from n-1 gas composition sensors at the previous detection time; and determining the goaf ignition warning coefficient based on the first temperature data and first gas composition data at the current detection time and the first temperature data and first gas composition data at the previous detection time.

[0048] According to one embodiment of the present invention, the current detection time can be the time after a certain distance of mining, when the newly formed goaf is isolated from the unmined longwall face. At the current time, n temperature sensors and gas composition sensors are located within the goaf, thus acquiring n first temperature data points and n first gas composition data points. At the previous detection time, n-1 temperature sensors and gas composition sensors were located within the goaf, thus acquiring n-1 first temperature data points and n-1 first gas composition data points.

[0049] According to one embodiment of the present invention, the goaf ignition warning coefficient is determined based on the first temperature data and first gas composition data at the current detection time, and the first temperature data and first gas composition data at the previous detection time, including: determining the goaf ignition warning coefficient C according to formula (1). g ,

[0050]

[0051] Among them, T c,1,i T represents the first temperature data acquired by the i-th temperature sensor at the current detection time. p,1,i―1 T is the first temperature data acquired by the (i-1)th temperature sensor at the previous detection time. T As a preset temperature threshold, C O,c,i C represents the oxygen content data in the first gas component data acquired by the i-th gas component sensor at the current detection time. O,p,i―1C represents the oxygen content data from the first gas composition data acquired by the (i-1)th gas composition sensor at the previous detection time. OT Let i be the oxygen content threshold, max be the maximum value function, and if be the conditional function, i ≤ n, where i and n are both positive integers.

[0052] According to an embodiment of the present invention, in formula (1), Indicates in T c,1,i >T p,1,i―1 In this case, the value of the conditional function is Otherwise, the value is 0. As the coal mining process progresses, the number of temperature sensors in the goaf gradually increases. The distance between any temperature sensor in the goaf and the critical position between the goaf and the unmined longwall face also gradually increases as the mining process progresses. That is, the distance between the i-th temperature sensor at the current detection time and the aforementioned critical position is the same as the distance between the (i-1)-th temperature sensor at the previous detection time and the aforementioned critical position. Therefore, the temperature data collected by these two sensors can be compared. Since the oxygen source in the goaf is the air leaking from the isolation facility at the critical position, that is, the isolation facility is not tightly sealed, causing some air to enter the goaf through the critical position. However, the airflow through the adjacent position is less, resulting in thinner oxygen in the deeper parts of the roadway. The less oxygen is available for the combustible gas and the leaked coal in the goaf to burn, that is, the lower the possibility of ignition. Therefore, the smaller the serial number of the temperature sensor, the deeper it is in the roadway, and the lower the possibility of detecting high temperature when igniting. Since the distance between the i-th temperature sensor at the current detection time and the aforementioned critical position is the same as the distance between the (i-1)-th temperature sensor at the previous detection time and the aforementioned critical position, the oxygen content at the locations of these two temperature sensors is theoretically the same or similar at the two times. If T c,1,i >T p,1,i―1 If T is high, it indicates that the oxygen content at the current detection time is high (e.g., due to a large airflow caused by an inadequate seal in the isolation facility) or that the amount of combustible gas or coal at that location is large and burning. Therefore, in this situation, it indicates a high risk of fire at that location within the goaf. The relative difference between the first temperature data obtained by the i-th temperature sensor at the current detection time and the first temperature data obtained by the (i-1)-th temperature sensor at the previous detection time can be used as a conditional function value to describe the fire risk coefficient at the location of the i-th temperature sensor. Conversely, if T... c,1,i ≤T p,1,i―1 If the risk of fire at that location is low, the condition function value can be set to 0.

[0053] According to one embodiment of the present invention, the fire risk coefficient obtained above by longitudinally comparing the first temperature data at two detection times can also be determined by laterally analyzing the first temperature data measured by multiple temperature sensors at the current detection time. (Conditional function) Indicates the condition When true, the value of the conditional function is Otherwise, the conditional function value is 0. As mentioned above, the deeper the roadway, the thinner the oxygen, and the less oxygen is available for the combustion of combustible gases and missing coal in the goaf, meaning the probability of ignition is lower. Therefore, the smaller the temperature sensor number, the deeper it is in the roadway, and the lower the probability of detecting high temperatures during ignition. Based on this, a preset temperature threshold can be set. For example, the ignition temperature of combustible gases can be determined as the preset temperature threshold, and a temperature reference value can be determined for each temperature sensor location based on the preset temperature threshold. The smaller the temperature sensor number, the lower the reference value. If the first temperature data at the location of the i-th temperature sensor is higher than the temperature reference value, then although the probability of ignition at that location is low, the temperature still exceeds a lower standard, therefore, ignition is possible at that location. The temperature reference value is... That is, set a denominator that decreases as the sequence number increases. This design causes the temperature reference value to increase with increasing sequence number and decrease with decreasing sequence number, thus setting a lower standard for the location of temperature sensors with smaller sequence numbers. For comparison, if the first temperature data acquired by the i-th temperature sensor at the current detection time is higher than the corresponding temperature reference value, the relative difference between the first temperature data and the temperature reference value can be used as a conditional function value to represent the fire risk coefficient. The larger the relative difference, the higher the fire risk; conversely, if the first temperature data is lower than or equal to the corresponding temperature reference value, the fire risk is low, and the conditional function value is 0. The maximum value of these two fire risk coefficients can be taken as the temperature-based fire risk coefficient, thus objectively describing the fire risk determined based on temperature.

[0054] According to one embodiment of the present invention, on the other hand, the fire risk can also be determined from the oxygen content, condition function. Indicates in C O,c,i >C O,p,i―1 In this case, the value of the conditional function is Otherwise, it is 0, that is, in C O,c,i >C O,p,i―1 In this case, the fire risk factor is determined to be That is, the relative deviation between the oxygen content data in the first gas component data acquired by the i-th gas component sensor at the current detection time and the oxygen content data in the first gas component data acquired by the (i-1)-th gas component sensor at the previous detection time, in CO,c,i ≤C O,p,i―1 In the case of , the conditional function value is 0. The reason for comparing the oxygen content data in the first gas component data obtained by the i-th gas component sensor at the current detection time with the oxygen content data in the first gas component data obtained by the (i-1)-th gas component sensor at the previous detection time is similar to the reason for comparing the first temperature data obtained by the i-th temperature sensor at the current detection time with the first temperature data obtained by the (i-1)-th temperature sensor at the previous detection time, and will not be repeated here.

[0055] According to one embodiment of the present invention, similar to the temperature reference value described above, an oxygen content reference value can also be set, that is, an oxygen content threshold value can be set, and... This serves as a reference value for the oxygen content at the location of the i-th gas composition sensor. Indicates in In this case, the value of the conditional function is Otherwise, it is 0. That is, if the oxygen content data exceeds the oxygen content reference value, the relative deviation between the oxygen content data and the oxygen content reference value is used as the fire risk coefficient; otherwise, the fire risk coefficient is 0. The maximum value of the above two fire risk coefficients can be used as the fire risk coefficient based on oxygen content.

[0056] According to one embodiment of the present invention, since ignition requires both temperature and oxygen content to meet the ignition requirements, the ignition risk coefficient determined based on temperature can be multiplied by the ignition risk coefficient based on oxygen content to obtain the overall ignition risk coefficient. Furthermore, the maximum value of the overall ignition risk coefficient at the locations of multiple sensor groups can be used as the goaf ignition early warning coefficient, thereby describing the overall ignition risk within the goaf.

[0057] In this way, the first temperature and oxygen content data at the current detection time can be compared longitudinally with those at the previous detection time based on the distance between the current detection time and the critical position. Reference values ​​can also be set based on the distance between the sensor group location and the critical position, thereby enabling lateral analysis of the first temperature and oxygen content data at the current detection time. This allows for the acquisition of fire risk coefficients based on temperature and oxygen content, which are then multiplied to obtain the overall fire risk coefficient. This approach can analyze multiple factors contributing to fire risk, improving the comprehensiveness and accuracy of goaf fire analysis.

[0058] According to one embodiment of the present invention, in step S105, a fire warning coefficient for the longwall face can be determined to describe the fire risk of the longwall face.

[0059] According to one embodiment of the present invention, determining the fire warning coefficient of the longwall face based on the first gas composition data, the second temperature data, and the second gas composition data includes: determining the fire risk coefficient of the longwall face based on the second temperature data; determining the environmental risk coefficient of the longwall face based on the second temperature data, the second gas composition data, and the first gas composition data; and determining the fire warning coefficient of the longwall face based on the fire risk coefficient and the environmental risk coefficient of the longwall face.

[0060] According to one embodiment of the present invention, determining the fire risk coefficient of the longwall face based on the second temperature data includes: acquiring second temperature data obtained by m temperature sensors at the current detection time; acquiring second temperature data obtained by m+1 temperature sensors at the previous detection time; and determining the fire risk coefficient of the longwall face based on the second temperature data at the current detection time and the second temperature data at the previous detection time.

[0061] According to one embodiment of the present invention, as described above, as the mining process proceeds, the number of second temperature data and second gas composition data acquired each time is one less than the number of second temperature data and second gas composition data acquired in the previous time. Therefore, at the current detection time, a total of m second temperature data from temperature sensors are acquired, and at the previous detection time, a total of m+1 second temperature data from temperature sensors are acquired.

[0062] According to one embodiment of the present invention, the fire risk coefficient of the longwall face is determined based on the second temperature data at the current detection time and the second temperature data at the previous detection time, including: identifying a target temperature sensor whose second temperature data is greater than or equal to a preset temperature threshold among m temperature sensors at the current detection time; performing connectivity analysis on the target temperature sensor to obtain the connected components of the target temperature sensor; and determining the fire risk coefficient C of the longwall face according to formula (2). f ,

[0063]

[0064] Among them, T c,2,j T represents the second temperature data acquired by the j-th temperature sensor at the current detection time. p,2,j+1 T is the first temperature data acquired by the (j+1)th temperature sensor at the previous detection time. T For the preset temperature threshold, N max The maximum number of target temperature sensors included in the connected domain of each target temperature sensor is given by max, which is the maximum value function, and if is the conditional function, where j ≤ m and j and m are both positive integers.

[0065] According to an embodiment of the present invention, in formula (2), Indicates in T c,2,j >T p,2,j+1 In this case, the value of the conditional function is Otherwise, it is 0. As the mining process progresses, the number of sensor groups in the unmined longwall face decreases. Therefore, the position of the j-th temperature sensor at the current detection time is the same as the position of the (j+1)-th temperature sensor at the previous detection time. Therefore, if T c,2,j >T p,2,j+1 This indicates that the temperature at the location of the j-th temperature sensor at the current detection moment is rising, possibly due to spontaneous combustion. The relative magnitude of this rise can be used. The fire risk factor is used as the fire risk coefficient; otherwise, the conditional function value is 0. Alternatively, the fire risk coefficient can be determined by comparing the temperature at the location of the j-th temperature sensor with the ignition temperature of the combustible gas (i.e., a preset temperature threshold). Indicates in T c,2,j >T T In this case, the value of the conditional function is Otherwise, the value is 0. Since ventilation is required at the mining face, the oxygen content is sufficient. Only the relationship between the second temperature data and the preset temperature threshold needs to be compared. If the second temperature data exceeds the preset temperature threshold, it indicates a fire risk. The relative difference between the second temperature data and the preset temperature threshold can be used as the fire risk coefficient; otherwise, the conditional function value can be set to 0. Therefore, the maximum value of the two fire risk coefficients can be taken as the temperature-based fire risk coefficient for the location of the j-th temperature sensor. Furthermore, the maximum value of the temperature-based fire risk coefficients at each location can be taken as the temperature-based fire risk coefficient for the longwall mining face.

[0066] According to one embodiment of the present invention, The fire risk coefficient is the ratio of the number of target temperature sensors whose second temperature data exceeds a preset temperature threshold to the total number of temperature sensors in the longwall face at the current detection time. A larger ratio indicates a greater number of locations with fire risk, and thus a higher overall fire risk. Therefore, this ratio can be used as a quantity-based fire risk coefficient for the longwall face. Multiplying the temperature-based fire risk coefficient by the quantity-based fire risk coefficient yields the longwall face fire risk coefficient, which describes the overall fire risk of the longwall face.

[0067] In this way, the temperature-based fire risk coefficient can be determined by longitudinally comparing the second temperature data at the current detection time and the previous detection time, as well as by comparing the second temperature data at the current time with the preset temperature threshold. The quantity-based fire risk coefficient can also be determined by the number of locations with fire risk, thereby obtaining the fire risk coefficient of the longwall face and improving the comprehensiveness and accuracy of fire risk monitoring of the longwall face.

[0068] According to one embodiment of the present invention, the environmental risk coefficient of the longwall face can be used to represent the hazard of risk factors such as combustible gases in the area where the longwall face is located. Determining the environmental risk coefficient of the longwall face based on the second temperature data, the second gas composition data, and the first gas composition data includes: determining the content of a first combustible gas at the location of each gas composition sensor based on the first gas composition data acquired by multiple gas composition sensors at the current detection time; determining the content of a second combustible gas at the location of each gas composition sensor based on the second gas composition data acquired by multiple gas composition sensors at the current detection time; obtaining the ignition temperature of the combustible gas; and determining the environmental risk coefficient of the longwall face based on the ignition temperature, the content of the first combustible gas, the content of the second combustible gas, and the second temperature data.

[0069] According to one embodiment of the present invention, the combustible gas in the mine includes methane, carbon monoxide, etc., and the first combustible gas content and the second combustible gas content both represent the total content of various combustible gases. The ignition temperature of the combustible gas is the ignition temperature of the combustible gas with the lowest ignition point among the various combustible gases.

[0070] According to an embodiment of the present invention, the environmental risk coefficient of the longwall face is determined based on the ignition temperature, the content of the first combustible gas, the content of the second combustible gas, and the second temperature data, including: determining the environmental risk coefficient C of the longwall face according to formula (3). e ,

[0071]

[0072] Among them, C c,2,max C represents the maximum value of the second combustible gas content at the locations of multiple gas composition sensors. c,1,min C represents the minimum content of the first combustible gas at the location of multiple gas composition sensors. c,2,j C is the content of the second combustible gas determined based on the second gas component data detected by the j-th gas component sensor out of m gas component sensors at the current detection time. c,p,2,j+1 T is the content of the second combustible gas determined based on the second gas component data detected by the (j+1)th gas component sensor out of the m+1 gas component sensors at the previous detection time.c,2,max T is the maximum value among the second temperature data acquired by multiple temperature sensors at the current detection time. f The ignition temperature is [value missing].

[0073] According to one embodiment of the present invention, the combustible gas is usually the combustible gas that seeps out after coal seam mining. Since the sealing of the isolation facilities between the longwall face and the goaf may not be tight, a certain amount of combustible gas may leak out. Therefore, there may also be a certain amount of combustible gas in the longwall face. Generally, the content of combustible gas in the goaf is higher than that in the longwall face that has not yet been mined. In formula (3), the maximum value of the second combustible gas content can be compared with the minimum value of the first combustible gas content to obtain... A high ratio indicates the presence of flammable gas concentrations near the goaf within the longwall face, posing a certain environmental risk. On the other hand, This represents the relative change between the second combustible gas content determined by the second gas component data detected by the j-th gas component sensor at the current detection time and the second combustible gas content determined by the second gas component data detected by the (j+1)-th gas component sensor at the previous detection time. In other words, it represents the relative change in combustible gas content at the same location at different times. The maximum value of the relative change in combustible gas content at each location can be taken. A larger maximum value indicates that the combustible gas content is rising rapidly, posing a certain environmental risk. The two values ​​can be multiplied to obtain an environmental risk coefficient based on the combustible gas concentration.

[0074] According to one embodiment of the present invention, max j∈[1,m―1] (T c,2,j ―T p,2,j+1 T represents the maximum temperature difference at the same location at different times, and can be used to represent the maximum change in temperature rise. f ―T c,2,max This indicates the difference between the ignition temperature of the combustible gas and the maximum value among multiple second temperature data at the current detection time. This can be represented as the time required for the location with the highest temperature to reach the ignition temperature when the temperature changes according to the maximum change. The shorter this time, the greater the environmental risk. Therefore, it can be calculated by reciprocal, i.e., As a temperature-based environmental risk coefficient, since combustible gas requires a certain concentration and a certain temperature to ignite, the environmental risk coefficient based on combustible gas concentration and the environmental risk coefficient based on temperature can be multiplied to obtain the environmental risk coefficient of the longwall face, which is used to represent the overall degree of danger of the longwall face environment.

[0075] In this way, the environmental risk coefficient based on combustible gas concentration can be determined by comparing the combustible gas concentration in the goaf and the longwall face, as well as the relative change in combustible gas concentration in the longwall face. Furthermore, the time required for the location with the highest temperature to reach the ignition temperature under the condition of maximum change can be determined, thus establishing the environmental risk coefficient based on temperature. By obtaining the environmental risk coefficient of the longwall face from both the combustible gas concentration-based and temperature-based perspectives, the environmental hazards of the longwall face can be accurately described, improving the accuracy and comprehensiveness of environmental risk description.

[0076] According to one embodiment of the present invention, the fire risk coefficient and the environmental risk coefficient of the longwall face can be weighted and summed to obtain the fire warning coefficient of the longwall face.

[0077] According to one embodiment of the present invention, in step S106, if either the goaf ignition warning coefficient or the longwall face ignition warning coefficient is greater than or equal to a coefficient threshold, warning information can be generated. In step S107, corresponding ignition prevention measures are determined based on the warning information; that is, suitable ignition prevention measures are determined based on the two coefficients included in the warning information. In the example, when the goaf ignition warning coefficient is higher than the coefficient threshold, measures such as nitrogen injection into the goaf can be used to reduce the risk of ignition. When the longwall face ignition warning coefficient is higher than the coefficient threshold, measures such as three-phase foam injection can be used to reduce the risk of ignition. The ignition prevention measures are then implemented in step S108.

[0078] According to an embodiment of the present invention, the method for early warning of spontaneous combustion of coal seams during the recovery of the longwall face can set temperature sensors and gas composition sensors in the coal mining direction and continuously collect data from the goaf and the longwall face as the mining process progresses, thereby comprehensively monitoring the goaf and the longwall face. It can also compare the first gas composition data of the goaf with the second gas composition data of the longwall face to determine environmental hazards at the longwall face, improving the accuracy and comprehensiveness of monitoring. When determining the goaf ignition early warning coefficient, the first temperature and oxygen content data at the current detection time can be longitudinally compared with the first temperature and oxygen content data at the previous detection time based on the distance between the current detection time and the critical position. Reference values ​​can also be set based on the distance between the sensor group location and the critical position, thereby performing a horizontal analysis of the first temperature and oxygen content data at the current detection time to obtain a temperature-based ignition risk coefficient and an oxygen content-based ignition risk coefficient. Multiplying these two coefficients yields the overall ignition risk coefficient, allowing for the analysis of multiple factors contributing to ignition risk and improving the comprehensiveness and accuracy of goaf ignition analysis. When determining the ignition risk coefficient of a longwall face, a temperature-based ignition risk coefficient can be determined by longitudinally comparing the second temperature data at the current and previous detection times, and by comparing the current second temperature data with a preset temperature threshold. Alternatively, a quantity-based ignition risk coefficient can be determined by the number of locations with ignition risk, thus obtaining the longwall face ignition risk coefficient and improving the comprehensiveness and accuracy of longwall face ignition risk monitoring. When determining the environmental risk coefficient of a longwall face, a combustible gas concentration-based environmental risk coefficient can be determined by comparing the combustible gas concentrations in the goaf and the longwall face, and by the relative change in combustible gas concentration at the longwall face. Furthermore, the time required for the location with the highest temperature to reach the ignition temperature under the condition of maximum change can be determined, thus determining the temperature-based environmental risk coefficient. Therefore, obtaining the longwall face environmental risk coefficient based on both combustible gas concentration-based and temperature-based environmental risk coefficients allows for an accurate description of environmental hazards at the longwall face, improving the accuracy and comprehensiveness of environmental risk description.

[0079] Figure 2 An exemplary block diagram of a coal seam spontaneous combustion early warning system during the recovery of a longwall face according to an embodiment of the present invention is shown, the system comprising:

[0080] The module is used to uniformly set temperature sensors and gas composition sensors along the coal collection direction in the roadway of the longwall mining face.

[0081] The first acquisition module is used to acquire first temperature data through a temperature sensor in the goaf and first gas composition data through a gas composition sensor in the goaf during the coal mining process.

[0082] The second acquisition module is used to acquire second temperature data through a temperature sensor in the roadway of the longwall mining face during the coal mining process, and to acquire second gas composition data through a gas composition sensor in the roadway of the longwall mining face.

[0083] The goaf ignition early warning coefficient module is used to determine the goaf ignition early warning coefficient based on the first temperature data and the first gas composition data.

[0084] The longwall face ignition early warning coefficient module is used to determine the longwall face ignition early warning coefficient based on the first gas composition data, the second temperature data, and the second gas composition data.

[0085] The early warning information module is used to determine early warning information based on the fire warning coefficient of the goaf and the fire warning coefficient of the longwall face.

[0086] The fire prevention measures module is used to determine the corresponding fire prevention measures based on the warning information.

[0087] The implementation module is used to implement the fire prevention measures corresponding to the warning information.

[0088] Those skilled in the art should understand that the embodiments of the present invention described above and shown in the accompanying drawings are merely examples and do not limit the present invention. The objectives of the present invention have been fully and effectively achieved. The functions and structural principles of the present invention have been demonstrated and explained in the embodiments, and any variations or modifications may be made to the implementation of the present invention without departing from the stated principles.

[0089] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for early warning of spontaneous combustion of coal seams during the recovery period of a longwall mining face, characterized in that, include: Temperature sensors and gas composition sensors are evenly installed along the coal mining direction in the roadway of the longwall face. During the coal mining process, as the mining process proceeds, the first temperature data is obtained through the temperature sensor in the formed goaf, and the first gas composition data is obtained through the gas composition sensor in the goaf. During the coal mining process, second temperature data is obtained through temperature sensors in the roadways of the longwall face, and second gas composition data is obtained through gas composition sensors in the roadways of the longwall face. Based on the first temperature data and the first gas composition data, determine the early warning coefficient for goaf ignition. Based on the first gas composition data, the second temperature data, and the second gas composition data, determine the fire warning coefficient for the longwall mining face; The warning information is determined based on the fire warning coefficient of the goaf and the fire warning coefficient of the longwall face; Based on the aforementioned warning information, determine the corresponding fire prevention measures; Implement fire prevention measures corresponding to the aforementioned warning information; Based on the first temperature data and the first gas composition data, the goaf ignition early warning coefficient is determined, including: Acquire the first temperature data obtained by n temperature sensors and the first gas composition data obtained by n gas composition sensors at the current detection time; Acquire the first temperature data obtained by n-1 temperature sensors and the first gas composition data obtained by n-1 gas composition sensors at the previous detection time. Based on the first temperature data and first gas composition data at the current detection time, as well as the first temperature data and first gas composition data at the previous detection time, the goaf ignition warning coefficient is determined. Based on the first temperature and first gas composition data at the current detection time, and the first temperature and first gas composition data at the previous detection time, the goaf ignition early warning coefficient is determined, including: According to the formula ， Determine the early warning coefficient for fire in goaf areas ,in, This is the first temperature data acquired by the i-th temperature sensor at the current detection time. The first temperature data acquired by the (i-1)th temperature sensor at the previous detection time. To preset the temperature threshold, This refers to the oxygen content data in the first gas component data acquired by the i-th gas component sensor at the current detection time. The oxygen content data is from the first gas composition data acquired by the (i-1)th gas composition sensor at the previous detection time. Let i be the oxygen content threshold, max be the maximum value function, and if be the conditional function, i ≤ n, where i and n are both positive integers.

2. The method for early warning of spontaneous combustion of coal seams during the recovery period of a longwall face according to claim 1, characterized in that, Based on the first gas composition data, the second temperature data, and the second gas composition data, the fire warning coefficient for the longwall mining face is determined, including: Based on the second temperature data, the fire risk coefficient of the longwall face is determined; The environmental risk coefficient of the longwall mining face is determined based on the second temperature data, the second gas composition data, and the first gas composition data. The fire warning coefficient of the longwall face is determined based on the fire risk coefficient and the environmental risk coefficient of the longwall face.

3. The method for early warning of spontaneous combustion of coal seams during the recovery period of a longwall face according to claim 2, characterized in that, Based on the second temperature data, the fire risk coefficient of the longwall face is determined, including: Obtain the second temperature data acquired by m temperature sensors at the current detection time; Obtain the second temperature data acquired by the m+1 temperature sensors at the previous detection time; Based on the second temperature data at the current detection time and the second temperature data at the previous detection time, the fire risk coefficient of the longwall face is determined.

4. The method for early warning of spontaneous combustion of coal seams during the recovery period of a longwall face according to claim 3, characterized in that, Based on the second temperature data at the current detection time and the second temperature data at the previous detection time, the fire risk coefficient of the longwall face is determined, including: Among the m temperature sensors at the current detection time, identify the target temperature sensor whose second temperature data is greater than or equal to a preset temperature threshold. Perform connected component analysis on the target temperature sensor to obtain the connected components of the target temperature sensor; According to the formula ， Determine the risk coefficient of ignition at the longwall mining face ,in, This is the second temperature data acquired by the j-th temperature sensor at the current detection time. This refers to the second temperature data acquired by the (j+1)th temperature sensor at the previous detection time. To preset the temperature threshold, The maximum number of target temperature sensors included in the connected domain of each target temperature sensor is given by max, which is the maximum value function, and if is the conditional function, where j ≤ m and j and m are both positive integers.

5. The method for early warning of spontaneous combustion of coal seams during the recovery period of a longwall face according to claim 4, characterized in that, Based on the second temperature data, the second gas composition data, and the first gas composition data, the environmental risk coefficient of the longwall mining face is determined, including: Based on the first gas composition data obtained by multiple gas composition sensors at the current detection time, the content of the first combustible gas at the location of each gas composition sensor is determined. Based on the second gas composition data acquired by multiple gas composition sensors at the current detection time, the content of the second combustible gas at the location of each gas composition sensor is determined. To obtain the ignition temperature of combustible gases; The environmental risk coefficient of the longwall mining face is determined based on the ignition temperature, the content of the first combustible gas, the content of the second combustible gas, and the second temperature data.

6. The method for early warning of spontaneous combustion of coal seams during the recovery period of a longwall mining face according to claim 5, characterized in that, Based on the ignition temperature, the content of the first combustible gas, the content of the second combustible gas, and the second temperature data, the environmental risk coefficient of the longwall face is determined, including: According to the formula ， Determine the environmental risk coefficient of the longwall mining face ,in, This represents the maximum value of the second combustible gas content at the locations of multiple gas composition sensors. This represents the minimum content of the first combustible gas at the locations of multiple gas composition sensors. The content of the second combustible gas is determined based on the second gas component data detected by the j-th gas component sensor out of m gas component sensors at the current detection time. The content of the second combustible gas is determined based on the second gas component data detected by the (j+1)th gas component sensor out of the m+1 gas component sensors at the previous detection time. The maximum value among the second temperature data acquired by multiple temperature sensors at the current detection moment. The ignition temperature is [value missing].

7. A coal seam spontaneous combustion early warning system during the recovery of a longwall face, used to execute the method as described in any one of claims 1-6, characterized in that, include: The module is used to uniformly set temperature sensors and gas composition sensors along the coal collection direction in the roadway of the longwall mining face. The first acquisition module is used to acquire first temperature data through a temperature sensor in the goaf and first gas composition data through a gas composition sensor in the goaf during the coal mining process. The second acquisition module is used to acquire second temperature data through a temperature sensor in the roadway of the longwall mining face during the coal mining process, and to acquire second gas composition data through a gas composition sensor in the roadway of the longwall mining face. The goaf ignition early warning coefficient module is used to determine the goaf ignition early warning coefficient based on the first temperature data and the first gas composition data. The longwall face ignition early warning coefficient module is used to determine the longwall face ignition early warning coefficient based on the first gas composition data, the second temperature data, and the second gas composition data. The early warning information module is used to determine early warning information based on the fire warning coefficient of the goaf and the fire warning coefficient of the longwall face. The fire prevention measures module is used to determine the corresponding fire prevention measures based on the warning information. The implementation module is used to implement the fire prevention measures corresponding to the warning information.

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