System and method for reducing concentration of methane in post-mining environment in real time

Abstract

The invention belongs to the field of pollution treatment of coal mine gas, and particularly relates to a system for reducing the concentration of methane in a post-mine environment in real time. The system comprises a bacterial liquid storage tank, a nutrient solution storage tank, a spraying device, a methane concentration detector, a bacterial liquid activity detector and a central controller, the bacterial liquid storage tank is used for storing bacterial liquid and providing the bacterial liquid for the spraying device; the nutrient solution storage tank conveys a nutrient solution for maintaining the activity of a bacterial solution to the bacterial solution storage tank; the spraying device receives the bacterial liquid and sprays the bacterial liquid to the environment behind the mine; the methane concentration detector detects the methane concentration in real time, and information is transmitted to the central controller; the bacterial liquid activity detector monitors the activity of the bacterial liquid, and information is transmitted to the central controller; the central controller is used for regulating and controlling the spraying amount and the nutrient solution supplementing amount. The system can be flexibly deployed according to after-mine activity scenes (such as crushing workshops and transportation galleries) of different scales, unattended real-time automatic operation is achieved, and the problem of treatment of escaping methane in after-mine activities is effectively solved.

Description

Technical Field

[0001] The present invention belongs to the field of coal mine gas pollution control, and particularly relates to a system and method for reducing methane concentration in a post-mine environment in real time. Background Art

[0002] Methane-oxidizing bacteria are microorganisms that use methane as their sole carbon and energy source and can be used as a biological method to degrade coal gas. Existing solutions often utilize porous materials impregnated orthogonally to the airflow, or direct the airflow through a biofilter to degrade exhaust gas. However, due to the large and wide-ranging fluctuations in methane concentrations in post-mining environments, and the need to improve the adhesion of bacterial solutions sprayed on coal seam surfaces, there are currently no active gas control methods for post-mining environments. Therefore, developing a dynamic post-mining methane degradation and safety control system and method based on methane-oxidizing bacterial solutions is of great value and significance for coal mine gas control and greenhouse gas mitigation. Summary of the Invention

[0003] In order to solve the problem mentioned in the background technology that the concentration of methane emitted from post-mine activity scenarios fluctuates greatly and over a wide range, and there is currently no active gas prevention and control measures for post-mine activity scenarios, the purpose of the present invention is to provide a system and method for real-time reduction of methane concentration in the post-mine environment for post-mine activity scenarios.

[0004] To achieve the above objectives, the present invention provides a system for reducing methane concentration in a post-mining environment in real time in a first aspect. The system comprises a bacterial solution storage tank, a nutrient solution storage tank, a spraying device, a methane concentration detector, a bacterial solution activity detector, and a central controller.

[0005] The bacterial liquid storage tank is used to store bacterial liquid containing methane oxidizing bacteria and provide the bacterial liquid to the spraying device;

[0006] The nutrient solution storage tank is used to deliver nutrient solution for maintaining the activity of the methane oxidizing bacteria to the bacterial solution storage tank;

[0007] The spraying device is used to receive the bacterial solution from the bacterial solution storage tank and spray the bacterial solution into the post-mining environment;

[0008] The methane concentration detector is used to detect the methane concentration in the post-mine environment in real time and transmit the detected methane concentration information to the central controller;

[0009] The bacterial liquid activity detector is used to monitor the activity of methane-oxidizing bacteria in the bacterial liquid storage tank and transmit the activity information obtained from the detection to the central controller;

[0010] The central controller regulates the spraying amount of the spraying device according to the methane concentration information, and regulates the amount of nutrient solution added from the nutrient solution storage tank to the bacteria solution storage tank according to the activity information.

[0011] Preferably, the system further comprises a water mist explosion suppression device for spraying water mist into the post-mine environment to prevent explosion.

[0012] Preferably, the system further comprises a support frame, the support frame comprising two support arms and at least one support cross bar, the two ends of the support cross bar being respectively fixed to the upper portions of the two support arms; wherein,

[0013] The methane concentration detector, the spraying device and the fine water mist explosion suppression device are fixed on the supporting crossbar;

[0014] Preferably, there are two support cross bars, and the support cross bar for fixing the fine water mist explosion suppression device is located above the support cross bar for fixing the spraying device;

[0015] Preferably, the support frame is fixed to the discharge end of the underground crusher, or the support frame is respectively arranged at the front and rear of the underground belt conveyor roller so that the bacterial liquid can be sprayed onto the solid surface in the post-mine environment, such as the coal surface.

[0016] A second aspect of the present invention provides a method for reducing methane concentration in a post-mine environment in real time using the above system, the method comprising the following steps:

[0017] (1) Setting the methane concentration threshold and bacterial liquid activity threshold through the central controller, and configuring the bacterial concentration and bacterial liquid ratio in the bacterial liquid storage tank;

[0018] (2) Using a methane concentration detector to collect real-time data on the methane concentration in the post-mine environment, and using a bacterial liquid activity detector to synchronously monitor the real-time data on the activity of methane-oxidizing bacteria in the bacterial liquid storage tank, and continuously transmitting the collected real-time data to the central controller;

[0019] (3) The central controller compares the real-time data value of the methane concentration information with the methane concentration threshold. If the methane concentration is greater than the set threshold, the central controller sprays bacterial liquid into the mining environment to degrade methane;

[0020] (4) The central controller compares the real-time data value of the activity information with the bacterial liquid activity threshold. If the bacterial liquid activity is lower than the set threshold, the central controller triggers the nutrient solution storage tank to replenish nutrient solution to restore the bacterial liquid activity.

[0021] In step (1) of the present invention, preferably, the bacterial solution comprises methane oxidizing bacteria, nutrient solution, viscosity enhancer and synergist; and the concentration of methane oxidizing bacteria in the bacterial solution is ≥1×10 8 CFU / mL;

[0022] Preferably, the methanotrophic bacteria include Methylococcus and Methylococcus in a ratio of 1:(2-3).

[0023] Preferably, based on the total amount of the bacterial liquid,

[0024] The nutrient solution in the bacterial liquid comprises 0.01-0.02 mol / L phosphate, 0.05-0.1 mol / L ammonium nitrate, 0.01-0.03 mol / L magnesium sulfate and 50-100 μM chelated iron, wherein the phosphate is derived from a phosphate buffer having a pH of 6.8-7.2; and / or

[0025] The viscosity enhancer in the bacterial solution includes 0.1%-0.3% xanthan gum, 0.05%-0.1% sodium carboxymethyl cellulose, 0.01%-0.03% polyacrylamide and 1%-2% glycerol; and / or

[0026] The synergist in the bacterial liquid includes: 50-100 mg / L of biological surfactant and 0.01%-0.02% of antifreeze protein.

[0027] In the present invention, unless otherwise specified, all percentages involved are by mass.

[0028] The beneficial effects of the present invention are:

[0029] 1. The present invention utilizes the characteristic of methane-oxidizing bacteria that uses methane as the sole carbon source and energy source for growth, and utilizes its biodegradation of methane, effectively solving the problem of treating unorganized methane leakage in post-mine activity scenarios, and providing an effective way to prevent and control gas leakage in post-mine activity scenarios.

[0030] Second, microorganisms are less harmful to the environment, and the greenhouse effect of methane is 20 to 30 times that of carbon dioxide. Therefore, methane is converted into microbial life substances and fixed under the action of methane-oxidizing bacteria, which plays an important role in reducing the methane content in the atmosphere and slowing down the global greenhouse effect.

[0031] 3. The system for reducing methane concentration in the post-mining environment in real time in the present invention integrates a methane concentration sensor, a bacterial liquid activity monitor and a central controller. It can adjust the spraying frequency and the amount of bacterial liquid replenishment in real time, realizing unmanned dynamic degradation of methane emitted during transportation.

[0032] 4. The present invention effectively integrates the biodegradation of methane-oxidizing bacteria and the safety joint control mechanism to form a dual protection of "biodegradation + physical explosion suppression", effectively controlling the production safety problems caused by gas accumulation reaching the lower explosion limit in closed or semi-closed post-mine activity scenarios, and ensuring safe production in coal mines.

[0033] The methane-oxidizing bacterial solution of the present invention features a composite bacterial consortium, optimized nutrition, a composite viscosity-enhancing component, and a synergistic enhancer. The multi-strain synergistic effect adapts to the fluctuating methane concentrations experienced in post-mining scenarios. Methylococcus adapts to high methane concentrations (>5%), while Methylcurvus is responsible for the sustained degradation of low methane concentrations (<1%). The dual strains achieve comprehensive coverage in fluctuating methane concentration scenarios. The strong adhesion of the composite viscosity-enhancing components, including xanthan gum, CMC, and PAM, mimics dust suppressants, ensures the bacterial solution adheres firmly to the coal surface, resisting wind erosion and significantly improving adhesion. Biosurfactants enhance coal dust wettability, while antifreeze proteins extend its applicability to low-temperature environments. This formulation, integrated with intelligent spraying, nutritional supplementation, and a safety control system, achieves an integrated methane treatment strategy characterized by efficient degradation, long-lasting adhesion, and automated maintenance.

[0034] 6. The system utilizes containerized modular units, adaptable to various scales of post-mining activities. Small workshops can deploy a single container system, while large transport corridors can use two containers in alternating operation, offering flexible deployment and a wide range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A schematic diagram of a system for reducing methane concentration in a post-mining environment in real time provided by the present invention; wherein,

[0036] 1-support arm, 2-support crossbar, 3-methane concentration detector, 4-spraying pipe network, 5-nozzle, 6-container, 7-nutrient solution storage tank, 8-bacteria liquid storage tank, 9-bacteria liquid activity detector, 10-water tank, 11-central controller, 12-fine water mist explosion suppression device, 13-first pressure pump, 14-second pressure pump, 15-first valve, 16-second valve, 17-third valve. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. That is, the embodiments described are only part of the embodiments of the present invention, rather than all embodiments.

[0038] like Figure 1 As shown, the system provided by the present invention for reducing the methane concentration in the post-mining environment in real time includes a bacterial liquid storage tank 8, a nutrient solution storage tank 7, a spraying device (including a spraying pipe network 4 and a nozzle 5), a methane concentration detector 3, a bacterial liquid activity detector 9 and a central controller 11.

[0039] In the present invention, the system preferably includes a water mist explosion suppression device 12 and a support frame.

[0040] In the present invention, the fine water mist explosion suppression device 12 is used to spray water mist into the post-mine environment to prevent explosion.

[0041] In some embodiments, the fine water mist explosion suppression device 12 includes a water inlet chamber and one or more spray heads. The water inlet chamber is connected to the water tank 10 through a second pressure pump 14 to receive water from the water tank 10 .

[0042] In some embodiments, the spray head is arranged on the water inlet chamber along the direction of the supporting cross bar 2 to spray water mist, such as spraying water mist downward.

[0043] In the present invention, the support frame includes two supporting vertical arms 1 and at least one supporting cross bar 2 , and both ends of the supporting cross bar 2 are respectively fixed to the upper parts of the two supporting vertical arms 1 .

[0044] In some embodiments, the support arm 1 fixes the support frame in an application scenario in a post-mine environment in a detachable manner.

[0045] In some embodiments, the methane concentration detector 3, the spraying device and the fine water mist explosion suppression device 12 are fixed on the support crossbar 2. They can be located on the same support crossbar 2 or on different support crossbars 2.

[0046] Preferably, two supporting cross bars 2 are provided, and the supporting cross bar 2 for fixing the fine water mist explosion suppression device 12 is located above the supporting cross bar 2 for fixing the spraying device.

[0047] In some embodiments, the support frame is fixed to the discharge end of the underground crusher, or the support frame is respectively arranged at the front and rear of the underground belt conveyor roller so that the bacterial liquid can be sprayed onto the solid surface in the post-mine environment, such as the coal surface.

[0048] In the present invention, the bacterial liquid storage tank 8 is used to store the bacterial liquid containing methane oxidizing bacteria and provide the bacterial liquid to the spraying device.

[0049] In some embodiments, the bacterial liquid storage tank 8 is connected to a spraying device (particularly a spraying pipe network 4 ) arranged on the supporting crossbar 2 , and the first pressure pump 13 provides the delivery power during the liquid supply process.

[0050] In the present invention, the nutrient solution storage tank 7 is connected to the input end of the bacteria solution storage tank 8 for delivering nutrient solution for maintaining the activity of the methane oxidizing bacteria to the bacteria solution storage tank 8 .

[0051] In the present invention, the spraying device is used to receive the bacterial solution from the bacterial solution storage tank 8 and spray the bacterial solution to the post-mining environment, so that the bacterial solution is sprayed onto the solid surface in the post-mining environment, such as the coal surface.

[0052] In some embodiments, the spraying device includes a spraying pipe network 4 connected to the bacterial liquid storage tank 8 and one or more nozzles 5 located at the end of the spraying pipe network 4.

[0053] In the present invention, the methane concentration detector 3 is used to detect the methane concentration in the post-mine environment in real time, and transmit the detected methane concentration information to the central controller 11.

[0054] In some embodiments, the methane concentration detector 3 is arranged on the supporting crossbar 2 and connected to the central controller 11 .

[0055] In some embodiments, the methane concentration detector 3 transmits the methane concentration of the post-mine activity scene to the central controller 11. Based on the methane concentration information, the central controller 11 adjusts the spraying flow rate of the spraying device when the second valve 16 is opened to degrade the methane. This allows for unmanned automatic adjustment of the spraying frequency and dynamically degrades the methane released during transportation.

[0056] In some embodiments, when the methane concentration detector 3 detects that the methane concentration in the post-mine environment reaches the explosion threshold, the second valve 16 is kept open, and the central controller 11 triggers the fine water mist explosion suppression device 12 to spray water mist.

[0057] In some embodiments, the fine water mist explosion suppression device 12 is on the supporting cross bar 2 , and the water mist required by the fine water mist explosion suppression device 12 comes from the water tank 10 , with the second pressure pump 14 providing the delivery power.

[0058] In some embodiments, when the methane concentration measured by the methane concentration detector 3 exceeds the set lower explosion limit, the first valve 15 is activated, and the water mist explosion suppression device 12 and the ventilation equipment are turned on simultaneously. These two methods enable the system of the present invention to provide dual protection of "biodegradation + physical explosion protection."

[0059] In the present invention, the bacterial liquid activity detector 9 is used to monitor the activity of methane oxidizing bacteria in the bacterial liquid storage tank 8 and transmit the activity information obtained by the detection to the central controller 11 .

[0060] In some embodiments, a bacterial liquid activity detector 9 is disposed in the bacterial liquid storage tank 8 and is connected to a central controller 11. When the bacterial liquid activity falls below an optimal bacterial liquid activity threshold, a third valve 17 is automatically opened, triggering the injection of nutrient solution from the nutrient solution storage tank 7. When the bacterial liquid activity reaches the optimal bacterial liquid activity threshold, the third valve 17 is automatically closed.

[0061] In the present invention, the central controller 11 controls the spraying amount of the spraying device according to the methane concentration information from the methane concentration detector 3 , and at the same time controls the amount of nutrient solution added from the nutrient solution storage tank 7 to the bacteria liquid storage tank 8 according to the activity information from the bacteria liquid activity detector 9 .

[0062] In the present invention, the system preferably includes a container 6, wherein the nutrient solution storage tank 7, the bacterial solution storage tank 8, the water tank 10, and the central controller 11 are all integrated and arranged in the container 7 for modular arrangement.

[0063] The method provided by the present invention for reducing methane concentration in a post-mine environment in real time using the above system comprises the following steps:

[0064] (1) The central controller 11 sets the methane concentration threshold and the bacterial liquid activity threshold, and configures the bacterial concentration and the bacterial liquid ratio in the bacterial liquid storage tank 8;

[0065] (2) Using a methane concentration detector 3 to collect real-time data on the methane concentration in the post-mine environment, and using a bacterial liquid activity detector 9 to synchronously monitor the real-time data on the activity of methane-oxidizing bacteria in the bacterial liquid storage tank 8, and continuously transmitting the collected real-time data to a central controller 11;

[0066] (3) The central controller 11 compares the real-time data value of the methane concentration information with the methane concentration threshold. If the methane concentration is greater than the set threshold, the central controller 11 sprays bacterial liquid into the mining environment to degrade methane;

[0067] (4) The central controller 11 compares the real-time data value of the activity information with the bacterial liquid activity threshold. If the bacterial liquid activity is lower than the set threshold, the central controller 11 triggers the nutrient solution storage tank 7 to replenish nutrient solution to the bacterial liquid storage tank 8 to restore the bacterial liquid activity.

[0068] In step (1) of the present invention, preferably, the components of the bacterial solution include methane-oxidizing bacteria, nutrient solution, viscosity enhancer and synergist, so as to better bind to the solid surface in the sprayed post-mining environment, such as coal surface, especially coal containing high volatile matter, such as bituminous coal; wherein the concentration of methane-oxidizing bacteria in the bacterial solution is ≥1×10 8 CFU / mL.

[0069] Preferably, the methanotrophic bacteria include a 1:(2-3) ratio of Methylococcus and Methylococcus. The inventors have found that among methanotrophic bacteria, Methylococcus adapts to high methane concentration environments (>5%), while Methylococcus is responsible for the sustained degradation of low methane concentrations (<1%). In this case, the two strains work together to achieve full coverage of fluctuating methane concentration scenarios.

[0070] In the present invention, the nutrient solution in the bacterial solution can optimize the metabolic activity of the bacterial colony. In some embodiments, based on the total amount of the bacterial solution, the nutrient solution includes the following components: phosphate (0.01-0.02 mol / L, from a phosphate buffer with a pH of 6.8-7.2), ammonium nitrate (0.05-0.1 mol / L), magnesium sulfate (0.01-0.03 mol / L), and chelated iron (e.g., EDTA-Fe, 50-100 μM). It is understood in the art that the above content is the content of the corresponding component in the bacterial solution, for example, ammonium nitrate (0.05-0.1 mol / L) means that the content of ammonium nitrate in the bacterial solution is 0.05-0.1 mol / L, and the rest is similar and will not be repeated.

[0071] In the present invention, the viscosity enhancer in the bacterial solution can enhance adhesion to solid surfaces, particularly coal surfaces. In some embodiments, the viscosity enhancer comprises the following components, based on the total amount of the bacterial solution: xanthan gum (0.1%-0.3%), sodium carboxymethylcellulose (CMC, 0.05%-0.1%), polyacrylamide (PAM, 0.01%-0.03%), and glycerol (1%-2%).

[0072] In the present invention, the synergist in the bacterial solution can improve the environmental adaptability of the bacterial solution. In some embodiments, the synergist includes the following components: a biosurfactant (e.g., rhamnolipid, 50-100 mg / L) and an antifreeze protein (0.01%-0.02%); wherein the antifreeze protein is well known in the art and can be, for example, antifreeze glycoprotein, antifreeze protein I, antifreeze protein II, antifreeze protein III, or antifreeze protein IV.

[0073] In some embodiments, in step (3), when the real-time data value of the methane concentration is less than 0.3% (i.e., at the methane concentration safety threshold), the basic spraying is maintained at 50% of the rated flow rate (the rated flow rate may be 70-90 L / min);

[0074] When the real-time data value of methane concentration is not less than 0.3% and less than 1% (i.e., at the methane concentration warning threshold), increase the spraying to 80% of the rated flow rate;

[0075] When the real-time data value of the methane concentration is not less than 1% and less than 4.5% (ie, at the dangerous threshold of methane concentration), full flow spraying and / or intermittent 120% rated flow spraying are adopted.

[0076] In some embodiments, in step (4), the activity of the bacterial solution in the bacterial solution storage tank is measured using an ATP fluorescence detector. When the bacterial solution activity is less than 0.15 nmol / L (i.e., at the bacterial solution loss threshold), a concentration of not less than 1.0×10 8CFU / mL of fresh bacterial solution, you can also optionally inject 10-20mL / min of full nutrient solution until the activity recovers to the optimal threshold;

[0077] When the bacterial liquid activity is not less than 0.15 nmol / L and less than 0.30 nmol / L (i.e., at the bacterial liquid activity danger threshold), the nutrient solution is continuously added to the bacterial liquid storage tank 8 at a flow rate of 5-15 mL / min;

[0078] When the bacterial liquid activity is not less than 0.30 nmol / L and less than 0.45 nmol / L (i.e., at the bacterial liquid activity warning threshold), nutrient solution is added to the bacterial liquid storage tank 8 in a pulsed manner at a flow rate of 2-10 mL / min, for example, for 2-5 minutes;

[0079] When the bacterial liquid activity is not less than 0.45 nmol / L (ie, at the optimal bacterial liquid activity threshold), there is no need to add nutrient solution to the bacterial liquid storage tank 8 .

[0080] Those skilled in the art will understand that when an ATP fluorescence detector measures bacterial activity, the direct reading of the instrument is in RLU (relative light units), which needs to be converted to nmol / L (i.e., ATP content) in this article based on the standard curve.

[0081] It is known in the art that the explosion limit of methane is approximately 5%.

[0082] In some embodiments, when the system further includes a water mist explosion suppression device 12, when the methane concentration exceeds the lower explosion limit threshold (for example, the methane concentration explosion threshold is set to 4.5%), the water mist explosion suppression device 12 is synchronously started by the central controller 11 to spray water mist, and the underground ventilation equipment is optionally turned on.

[0083] Preferably, the particle size of the water mist sprayed by the fine water mist explosion suppression device 12 is controlled at 50-100 μm (taking into account both methane dilution and dust suppression); the ventilation equipment makes the wind speed in the post-mine environment not less than 0.5 m / s.

[0084] In practical applications, a containerized modular unit can be used to integrate the nutrient solution storage tank 7, bacterial solution storage tank 8, water tank 10, and central controller 11 into a container 6. The containerized modular unit system is suitable for different scale post-mine activity scenarios, such as Figure 1 shown.

[0085] Example 1

[0086] like Figure 1 As shown, the present invention is further described by deploying a single-box system in a small crushing workshop of a coal mine. The specific process is as follows:

[0087] (1) The two supporting arms 1 of the support frame are fixed to the two sides of the inner wall of the crusher discharge end by bolts. A methane concentration detector 3 (connected to the central controller 11) and a spraying device (including a spraying pipe network 4 and a number of matching nozzles 5) are installed on the supporting cross bar 2 at the bottom, and a fine water mist explosion suppression device 12 is installed on the supporting cross bar 2 at the top.

[0088] (2) Install a bacterial liquid activity detector 9 (connected to the central controller 11) in the bacterial liquid storage tank 8. When the bacterial liquid activity detector 9 is connected to the central controller 11 and the bacterial liquid activity is less than 0.15 nmol / L, inject a solution with a concentration of not less than 1.0×10 8 CFU / mL of bacterial solution; when the bacterial solution activity is not less than 0.15nmol / L and less than 0.30nmol / L, the nutrient solution storage tank 7 continuously adds nutrient solution to the bacterial solution storage tank 8 at a flow rate of 10mL / min; when the bacterial solution activity is not less than 0.30nmol / L and less than 0.45nmol / L, the nutrient solution storage tank 7 pulses the nutrient solution to the bacterial solution storage tank 8 at a flow rate of 5mL / min for 2 minutes; when the bacterial solution activity is not less than 0.45nmol / L, no nutrient solution needs to be added;

[0089] The bacterial solution contains: 6.7×10 7 CFU / mL of Methylococcus Bath strain, 3.3×10 7 CFU / mL of Methylocybin OB3b strain, 0.015 mol / L phosphate, 0.08 mol / L ammonium nitrate, 0.02 mol / L magnesium sulfate, 75 μM EDTA-Fe, 0.2% xanthan gum, 0.08% sodium carboxymethyl cellulose (CMC), 0.02% polyacrylamide (PAM), 1.5% glycerol, 75 mg / L rhamnolipid, and 0.015% antifreeze protein.

[0090] (3) The methane concentration detector 3 transmits the methane concentration at the crusher discharge end to the central controller 11. When the methane concentration at the crusher discharge end is less than the set value, the spraying device (including the spraying pipe network 4 and the equipped nozzle 5) at the crusher discharge end is closed; when the real-time data value of the methane concentration is less than 0.3%, the nozzle 5 maintains basic spraying at 50% of the rated flow rate (wherein the rated flow rate is 80L / min); when the real-time data value of the methane concentration is not less than 0.3% and less than 1%, the spraying is increased to 80% of the rated flow rate; when the real-time data value of the methane concentration is not less than 1% and less than 4.5%, full flow spraying and intermittent 120% flow spraying are adopted.

[0091] The methane in the crushing workshop is degraded through the above methods.

[0092] (4) When the methane concentration measured by the methane concentration detector 3 is higher than the set lower explosion limit threshold, the first valve 15 is started synchronously, and the fine water mist explosion suppression device 12 and the ventilation system are opened to form a "biodegradation + physical explosion protection" double protection.

[0093] After operation, the methane concentration at the crusher discharge port dropped from the initial 1.5-4.2% to 0.3-0.8%; the average degradation rate in 24 hours was 82.7% (compared to the scenario without a spraying system, where only natural diffusion decreased by 12%). High-concentration methane (>3%) is mainly degraded by Methylococcus (degradation rate>70% within 4 hours), and low-concentration methane (<1%) is continuously removed by Methylococcus (degradation rate maintained above 60%). The residual rate of bacterial liquid on the coal surface is ≥85% (tested in a strong wind flow environment); the xanthan gum-PAM composite film-forming agent enables the bacterial liquid to form a 50-100μm biofilm on the coal surface, and the anti-peeling strength is increased by 3 times. The nutrient solution is automatically replenished and triggered twice a week, with zero manual intervention. The system automatically adjusts the spraying frequency according to the fluctuation of methane concentration (the spraying volume increases to 50L / min during high concentration periods and decreases to 10L / min during low concentration periods). Compared with the traditional method of only using ventilation to degrade methane, it saves 40% energy (no continuous high-power ventilation is required); the residual bacterial liquid in the coal has no effect on the subsequent washing process (biodegradable components, and the COD of the coal washing wastewater does not exceed the standard).

[0094] Example 2

[0095] The present invention is further described by using a model of configuring a double-box system for a large transport corridor in a coal mine. The specific process is the same as that of Example 1, with the only difference being that:

[0096] It is a double-box system, one set of support frames is fixed at the front of the belt conveyor, and the other set of support frames is fixed at the rear of the belt conveyor;

[0097] In step (2), among the methanotrophic bacteria, the proportion of Methylococcus in the methanotrophic bacteria mixture is increased to 70% (to cope with the concentrated escape of methane during transportation); in the bacterial solution, the content of xanthan gum is increased to 0.25%, the content of sodium carboxymethyl cellulose is increased to 0.1% (to adapt to the high wind speed of 12 m / s in the transportation corridor), and the content of antifreeze protein is increased to 0.02% (to adapt to the ambient temperature as low as -10°C to -15°C in the transportation corridor); and the rest are the same.

[0098] After operation, the methane concentration in the front control area (corresponding to the support frame at the front of the belt conveyor) dropped from approximately 3.8% to approximately 0.5% (degradation rate 86.8%); the methane concentration in the rear control area (corresponding to the support frame at the rear of the belt conveyor) dropped from approximately 2.1% to approximately 0.4% (degradation rate 81.0%); the concentration gradient difference was less than 0.3% (the dual detector linkage eliminated the risk of local accumulation). The residual rate of bacterial liquid on the coal surface was 81% (tested under a wind speed of 12m / s); the xanthan gum-CMC compound formed a tough biofilm of 80-120μm. The nutrient solution was automatically replenished 1.5 times / week (twice for a single-tank system). The viscosity enhancer ratio was optimized to solve the problem of peeling at high wind speeds; antifreeze protein maintained low-temperature enzyme activity, expanding its applicability in high-altitude mining areas. The methane concentrations in the front and rear sections were independently monitored to eliminate monitoring blind spots; the containers operated alternately (one in use and one in reserve) and automatically switched in the event of a failure. The methane escape rate is reduced by 18% compared to a single-box system; the unit methane control cost is reduced by 35% (compared to a solution with physical ventilation only).

[0099] Comparative Example 1

[0100] The only difference from Example 1 is that the synergist is missing.

[0101] After operation, insufficient wettability resulted in incomplete bacterial liquid coverage on the coal dust surface, and the 24-hour methane degradation rate was only 48%. The degradation time of high-concentration methane (>3%) was extended to 8 hours. The unabsorbed nutrient solution crystallized on the coal surface, shortening the bacterial liquid activity cycle and causing nutrient waste.

[0102] Comparative Example 2

[0103] The only difference from Example 1 is that the viscosity enhancer is missing.

[0104] After operation, the residual rate on the coal surface was only 32%, and the wind impact caused the bacterial liquid to be stripped off.

[0105] Comparative Example 3

[0106] The difference from Example 1 is that: Methylocybin is missing.

[0107] After operation, it was found that the metabolism of Methylococcus Bath stagnated at a methane concentration of less than 1% (the minimum growth threshold was 0.8%), resulting in methane accumulation during intermittent operation of the crusher. The measured methane concentration at the discharge port rebounded from 0.3% to 1.8% after 2 hours of shutdown; to compensate for the degradation gap, the spraying frequency was increased to 3 times that of Example 1, the frequency of automatic nutrient solution replenishment reached 5 times / week, and the system linkage load surged.

[0108] summary:

[0109] It can be seen from the above Examples 1-2 and Comparative Examples 1-3 that the post-mine methane dynamic degradation and safety joint control system and method provided by the present invention realizes the full-process control of post-mine methane through the deep coupling of bacterial liquid formula innovation, intelligent spraying control and safety joint control mechanism. First, multiple bacterial strains work together to adapt to the large fluctuations in methane concentration in post-mine activity scenarios. Methylococcus adapts to high methane concentration environments (>5%), and Methylcurvus is responsible for the continuous degradation of low-concentration methane (<1%). The two bacterial strains work together to achieve full spectrum coverage of methane concentration fluctuation scenarios; through the strong adhesion of the composite viscosity-increasing components of the dust suppressant formula such as xanthan gum, CMC, and PAM, the bacterial liquid is firmly attached to the coal surface, resisting wind erosion, and significantly improving adhesion; biological surfactants improve the wettability of coal dust, and antifreeze proteins expand low-temperature applicable scenarios. This formula is deeply coordinated with intelligent spraying, nutritional supplementation, and safety joint control systems to achieve integrated methane control of "efficient degradation + long-term adhesion + automatic maintenance." And increase the small-scale single-box deployment (Example 1) to a large-scale dual-box linkage (the methane escape rate of Example 2 is further reduced by 18% compared with Example 1).

[0110] Comparison between Example 1 and Comparative Example 1 shows that the synergist formulation of the present invention can increase wettability, prolong bacterial survival time, and increase bacterial liquid coverage on the coal dust surface. In Example 1, the degradation rate within 4 hours is greater than 70%, while the methane degradation rate within 24 hours in Comparative Example 1 without the synergist is only 48%.

[0111] A comparison of Example 1 and Comparative Example 2 shows that the biomimetic viscosity-enhancing technology used in the present invention, i.e., the xanthan gum-PAM-CMC compound, enables the bacterial liquid to form an 80-120 μm biofilm on the solid surface, so that the bacterial liquid firmly adheres to the coal surface, resists wind erosion, and significantly improves adhesion. The residual rate in Example 1 is 85%, while that in Comparative Example 2 without a viscosity-enhancing agent is only 32%.

[0112] From the comparison of Example 1 and Comparative Example 3, it can be seen that the composite bacterial community used in the present invention can be precisely adapted: Methylococcus (high concentration degradation) + Methylococcus (low concentration maintenance) form a full spectrum coverage of concentration fluctuations. The degradation rate of Example 1 is 82.7%, and the single bacterial system of Comparative Example 3 fails.

Claims

1. A system for reducing methane concentration in a post-mining environment in real time, characterized in that: The system includes a bacterial liquid storage tank, a nutrient solution storage tank, a spraying device, a methane concentration detector, a bacterial liquid activity detector and a central controller; wherein, The bacterial liquid storage tank is used to store bacterial liquid containing methane oxidizing bacteria and provide the bacterial liquid to the spraying device; The nutrient solution storage tank is used to deliver nutrient solution for maintaining the activity of the methane oxidizing bacteria to the bacterial solution storage tank; The spraying device is used to receive the bacterial solution from the bacterial solution storage tank and spray the bacterial solution into the post-mining environment; The methane concentration detector is used to detect the methane concentration in the post-mine environment in real time and transmit the detected methane concentration information to the central controller; The bacterial liquid activity detector is used to monitor the activity of methane-oxidizing bacteria in the bacterial liquid storage tank and transmit the activity information obtained from the detection to the central controller; The central controller regulates the spraying amount of the spraying device according to the methane concentration information, and regulates the amount of nutrient solution added from the nutrient solution storage tank to the bacteria solution storage tank according to the activity information.

2. The system according to claim 1, wherein: The system also includes a fine water mist explosion suppression device for spraying water mist into the post-mine environment to prevent explosion.

3. The system according to claim 2, characterized in that The system further comprises a support frame, the support frame comprising two support vertical arms and at least one support cross bar, both ends of the support cross bar being fixed to the upper portions of the two support vertical arms respectively; wherein, The methane concentration detector, the spraying device and the fine water mist explosion suppression device are fixed on the supporting crossbar; Preferably, there are two support cross bars, and the support cross bar for fixing the fine water mist explosion suppression device is located above the support cross bar for fixing the spraying device; Preferably, the support frame is fixed to the discharge end of the underground crusher, or the support frame is respectively arranged at the front and rear of the underground belt conveyor roller, so that the bacterial liquid can be sprayed onto the solid surface in the post-mine environment.

4. The system according to claim 3, characterized in that The spraying device includes a spraying pipe network connected to the bacterial liquid storage tank and one or more nozzles located at the end of the spraying pipe network; The fine water mist explosion suppression device includes a water inlet chamber and one or more spray heads. The water inlet chamber is connected to a water tank via a pressure pump to receive water from the water tank. The spray heads are arranged on the water inlet chamber along the direction of the supporting crossbar to spray water mist. Preferably, the system further comprises a container, and the nutrient solution storage tank, bacteria solution storage tank, water tank and central controller are all integrated and arranged in the container.

5. A method for reducing methane concentration in a post-mine environment in real time using the system according to any one of claims 1 to 4, characterized in that: The method comprises the following steps: (1) Setting the methane concentration threshold and bacterial liquid activity threshold through the central controller, and configuring the bacterial concentration and bacterial liquid ratio in the bacterial liquid storage tank; (2) Using a methane concentration detector to collect real-time data on the methane concentration in the post-mine environment, and using a bacterial liquid activity detector to synchronously monitor the real-time data on the activity of methane-oxidizing bacteria in the bacterial liquid storage tank, and continuously transmitting the collected real-time data to the central controller; (3) The central controller compares the real-time data value of the methane concentration information with the methane concentration threshold. If the methane concentration is greater than the set threshold, the central controller sprays bacterial liquid into the mining environment to degrade methane; (4) The central controller compares the real-time data value of the activity information with the bacterial liquid activity threshold. If the bacterial liquid activity is lower than the set threshold, the central controller triggers the nutrient solution storage tank to replenish nutrient solution to restore the bacterial liquid activity.

6. The method according to claim 5, characterized in that In step (1), the bacterial solution includes methane oxidizing bacteria, nutrient solution, viscosity enhancer and synergist; and the concentration of methane oxidizing bacteria in the bacterial solution is ≥1×10 8 CFU / mL; Preferably, the methanotrophic bacteria include Methylococcus and Methylococcus in a ratio of 1:(2-3).

7. The method according to claim 6, characterized in that Based on the total amount of the bacterial solution, The nutrient solution in the bacterial liquid comprises 0.01-0.02 mol / L phosphate, 0.05-0.1 mol / L ammonium nitrate, 0.01-0.03 mol / L magnesium sulfate and 50-100 μM chelated iron, wherein the phosphate is derived from a phosphate buffer having a pH of 6.8-7.2; and / or The viscosity enhancer in the bacterial solution includes 0.1%-0.3% xanthan gum, 0.05%-0.1% sodium carboxymethyl cellulose, 0.01%-0.03% polyacrylamide and 1%-2% glycerol; and / or The synergist in the bacterial liquid includes 50-100 mg / L of biological surfactant and 0.01%-0.02% of antifreeze protein.

8. The method according to claim 6 or 7, characterized in that In step (3), when the real-time data value of the methane concentration is less than 0.3%, spraying is performed at 50% of the rated flow rate; when the real-time data value of the methane concentration is not less than 0.3% and less than 1%, spraying is performed at 80% of the rated flow rate; when the real-time data value of the methane concentration is not less than 1% and less than 4.5%, spraying is performed at full flow rate or intermittently at 120% of the rated flow rate; The rated flow rate is 70-90 L / min.

9. The method according to any one of claims 6 to 8, characterized in that In step (4), the activity of the bacterial solution in the bacterial solution storage tank is measured by ATP fluorescence detector. When the bacterial solution activity is less than 0.15 nmol / L, a concentration of not less than 1.0×10 8 nmol / L bacterial solution; when the bacterial solution activity is not less than 0.15nmol / L and less than 0.30nmol / L, continuously add nutrient solution to the bacterial solution storage tank at a flow rate of 5-15mL / min; when the bacterial solution activity is not less than 0.30nmol / L and less than 0.45nmol / L, pulse-feed nutrient solution to the bacterial solution storage tank at a flow rate of 2-10mL / min; when the bacterial solution activity is not less than 0.45nmol / L, no nutrient solution needs to be added.

10. The method according to any one of claims 5 to 9, characterized in that When the system further includes a water mist explosion suppression device, when the methane concentration exceeds the methane concentration explosion threshold, the central controller synchronously starts the water mist explosion suppression device to spray water mist and optionally starts the underground ventilation equipment; Preferably, the particle size of the water mist sprayed by the fine water mist explosion suppression device is 50-100 μm; The ventilation equipment ensures that the wind speed in the post-mine environment is not less than 0.5 m / s.

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