A green method for preventing and extinguishing fires by microorganisms in goaf

Abstract

The present invention discloses a green microbial fire prevention and extinguishing method for gob areas. First, unequal-spacing gas sampling tube measuring points are arranged at the cutting face position to analyze the width of the gob area when it enters the oxidation zone. Then, as the working face advances, grouting pipelines are staggeredly arranged in the intake airway and return airway of the working face, and gas sampling tube monitoring points are buried again. The grouting pipelines and gas sampling tube monitoring points are buried into the gob area as the working face advances. Finally, when the gob area enters the oxidation and temperature-rising zone or abnormal conditions occur in the gob area, the microbial mixed liquid is injected into the gob area under pressure. The present invention aims at the easily self-igniting area in the three self-igniting zones of the gob area. By arranging the liquid injection pipelines and injecting the oxygen-consuming microbial mixed solution, it can consume the oxygen in the gob area, inhibit oxidation, and reduce the temperature, etc. It can not only improve the fire prevention and extinguishing efficiency of the gob area, but also the microbial technology itself is green and harmless and will not cause pollution and damage to the environment.

Description

Technical Field

[0001] The present invention belongs to the field of mine fire prevention and extinguishment, and particularly relates to a microbial green fire prevention and extinguishment method for gob areas. Background Art

[0002] Mine fires are one of the five major natural disasters in coal mines, which not only seriously threaten the safe production of coal mines, but also cause a large amount of coal resource losses. At the same time, a large amount of CO 2 and CO, SO 2 and other toxic and harmful gases are emitted, which greatly endanger people's health and safety and seriously damage the ecological environment. Among them, the gob area is one of the areas where coal spontaneous combustion is more likely to occur in underground coal mines. In addition, the fire source position in the gob area is hidden and difficult to determine, with a long distance and a large range, which more seriously affects coal mine safety.

[0003] At present, the main technologies for preventing and controlling coal spontaneous combustion in gob areas are grouting prevention and control technology, inhibitor (MgCl 2 , CaCl 2 , NaCl, ionic type, zinc-magnesium-aluminum layered double hydroxide, ammonium polyphosphate inhibitor, etc.) prevention and control technology, pressure equalization prevention and control technology, N 2 inert gas and CO 2 inert gas prevention and control technology, gel (foam adhesive, temperature-sensitive hydrogel, high-water colloid, composite colloid, etc.) prevention and control technology. For the grouting technology, its disadvantages are that the slurry only flows to the low-lying parts and cannot accumulate upward, which cannot cover the floating coal in the middle and high coal bodies, and it is easy to run and burst, resulting in a large amount of dehydration, deteriorating the underground working environment and affecting the coal quality. Although its material cost is low, the material waste is also huge; for the inhibitor technology, its disadvantages are that the inhibitor is not easily evenly dispersed on the coal body, the spraying process is difficult to implement, it corrodes underground equipment and affects the health of underground workers; although the pressure equalization fire prevention and extinguishment technology has flexible implementation methods and low implementation costs, it can improve the working environment and reduce the influx of harmful gases into the working face, but the process is complex, affecting normal production, with a large amount of work and cannot fundamentally control the fire area; the application conditions of inert gas fire prevention and extinguishment are limited, and only the fire areas with good sealing effects are suitable to be selected. Otherwise, the inert gas will escape on a large scale, easily diffuse with air leakage and cause pollution, and it is not easy to stay in the injected area. The nitrogen injection machine needs to be maintained frequently, and the cooling and fire extinguishing effects are poor; for the gel prevention and control technology, its technical disadvantages are poor fluidity, small flow rate, difficult to use on a large area, the gel will crack after losing water, and the cost is relatively high. Therefore, aiming at the deficiencies of the existing fire prevention and extinguishment technologies for gob areas, the present invention proposes a microbial green fire prevention and extinguishment method for gob areas. For the easily spontaneous combustion areas in the "three zones" of spontaneous combustion in the gob area, by leaving grouting pipelines and constructing boreholes, a mixed solution of oxygen-consuming microorganisms is used to consume oxygen, inhibit oxidation, cool down, etc. in the gob area. It can not only reduce the oxygen concentration in the gob area to prevent coal spontaneous combustion, but also has the characteristics of inhibiting combustion itself, realizing green and effective prevention and control of the spontaneous combustion of the remaining coal in the gob area. Summary of the Invention

[0004] In view of the problems existing in the prior art, the present invention provides a green microbial fire prevention and extinguishing method for gob areas. Most mine fires occur in gob areas, and the main reason for ignition is the leakage of air and oxygen supply in the gob area. By injecting a mixed bacterial solution containing oxygen-consuming microorganisms into the gob area, the present invention can not only reduce the oxygen concentration in the gob area to prevent coal spontaneous combustion, but also has the characteristics of inhibiting combustion itself, realizing green and effective prevention and control of spontaneous combustion of residual coal in the gob area.

[0005] After the present invention is injected into the gob area, the oxygen-consuming microorganisms therein consume a large amount of oxygen, reducing the oxygen concentration in the gob area, narrowing the ranges of the heat dissipation zone and the oxidation zone in the "three zones" of spontaneous combustion in the gob area, forcing the residual coal in the gob area to enter the asphyxiation zone as soon as possible, and reducing the risk of spontaneous combustion of residual coal; secondly, in addition to containing nutrients that meet the needs of microorganisms, the culture medium for microorganism growth can be added with other additives that do not affect the oxygen-consuming activity of microorganisms, such as inhibitor, so that the surface of the easily self-igniting coal body is covered, forming a plug for the pores and fissures of coal particles, preventing the contact between oxygen and residual coal; moreover, the oxygen-consuming microorganisms are injected into the gob area with an aqueous solution as the carrier, and the solution is a multi-component mixed aqueous solution. On the one hand, the moisture can moisten the coal body in the gob area, and on the other hand, when the moisture evaporates by heating, it will carry away a large amount of heat to reduce the temperature of the coal body and prevent coal spontaneous combustion.

[0006] Advantages: The method of the present invention can play multiple roles in reducing the oxygen concentration in the gob area, destroying the heat storage environment, and blocking the contact between coal and oxygen in the gob area. The beneficial effects of this green microbial fire prevention and extinguishing technology are reflected in the following aspects:

[0007] (1) When the green microbial fire prevention and extinguishing technology method for gob areas is used to treat the gob area, the grouting system of the mine can be utilized, and there is no need to construct a new injection system, which has strong operability;

[0008] (2) By using the method of the present invention, a large amount of oxygen can be consumed, the oxygen concentration in the gob area can be reduced, and the ranges of the heat dissipation zone and the oxidation zone in the three zones of spontaneous combustion in the gob area can be narrowed; other additives that do not affect the activity of microorganisms can be added to form a plug for the pores and fissures of coal particles to prevent the contact between oxygen and residual coal; the solution is a multi-component mixed aqueous solution. On the one hand, the moisture can moisten the coal body in the gob area, and on the other hand, when the moisture evaporates by heating, it will carry away a large amount of heat to reduce the temperature of the coal body and prevent coal spontaneous combustion.

[0009] (3) The selected microorganisms are not limited to a certain strain, and can be used to quickly treat the high-temperature ignition points in the gob area or to treat the gob area on a large scale to prevent spontaneous ignition in the gob area.

[0010] (4) According to the "three zones" of spontaneous combustion in the goaf after the application of the microbial green fire prevention and extinguishing technology, the range of the oxidation zone is greatly reduced, which can increase the minimum advancing speed of the working face for preventing spontaneous combustion in the goaf and relieve the production pressure.

[0011] (5) The microbial technology itself is green and harmless and has no pollution to the environment. Description of the Drawings

[0012] Figure 1 It is the flow chart of the microbial green fire prevention and extinguishing method in the goaf of the present invention;

[0013] Figure 2 It is the schematic diagram of the "three zones" of spontaneous combustion in the goaf and the layout of the liquid injection pipeline and the bundle tube of the present invention;

[0014] Figure 3 It is the diagram of the "three zones" of spontaneous combustion in the goaf after the application of the microbial green fire prevention and extinguishing technology in the goaf of the present invention. Detailed Embodiment

[0015] In order to make the purpose, technical solutions and advantages of the present invention clearer, the following further describes the present invention in detail with reference to the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention, that is, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0016] There is residual coal in the goaf. According to the ease of spontaneous combustion of this residual coal in the goaf, the goaf is divided into three horizontal zones: the heat dissipation zone 9, the oxidation zone 10 and the asphyxiation zone 11, as Figure 2 、 Figure 3As shown in the figure. The residual coal in the goaf will spontaneously ignite when it accumulates to a certain thickness, has the tendency of spontaneous combustion, sufficient oxygen supply, and suitable air leakage conditions. In a certain area of the goaf, the residual coal will spontaneously ignite, and this area is called the oxidation zone 10. Since the heat dissipation zone 9 is close to the working face 8, the air leakage in the goaf is relatively serious, resulting in a high oxygen content in this area. When coal comes into contact with oxygen, it is easy to react. Although a certain amount of heat will be generated, due to the large amount of air leakage and high wind speed in this area, the generated heat will leak, which hinders the spontaneous combustion of the residual coal. The oxidation zone 10 is the place where the residual coal in the goaf is prone to spontaneous combustion. In some areas of the heat dissipation zone 9, due to the air leakage bringing in sufficient oxygen, the heat generated by coal oxidation is easy to accumulate, which is conducive to the spontaneous combustion of the residual coal. In the asphyxiation zone 11, due to the collapse of the overlying strata and continuous extrusion, the porosity in the rock becomes very small. The air volume leaking into the goaf is very small and the wind speed is very low in this area and gradually disappears. The oxygen concentration decreases gradually in the asphyxiation zone because it is consumed in the oxidation zone. Therefore, coal oxidation reaction is not conducive to occur in this area and it is not easy for the residual coal to spontaneously ignite. Through the technical method provided by the present invention, the mixed solution of oxygen-consuming microorganisms is used to consume oxygen, inhibit, cool down, etc. in the goaf. By reserving the liquid injection pipeline and the directional drilling injection method, the range of the oxidation zone in the "three zones" of spontaneous combustion in the goaf can be effectively reduced, and the occurrence of spontaneous combustion accidents of the residual coal in the goaf can be prevented.

[0017] Refer to Figure 1 、 Figure 2 and Figure 3 , a microbial green fire prevention and extinguishing technology method for goafs of the present invention includes the following steps:

[0018] Step 1: During the mining process of the "U"-type ventilation fully-mechanized mining face, an air inlet roadway vacuum pump bundle gas sampling point 1 and a return air roadway vacuum pump bundle gas sampling point 13 are set in the air inlet roadway 12 and the return air roadway 7 of the working face, and a cut-through bundle gas monitoring point I6 is set to monitor the gas in the goaf. The layout of the cut-through bundle gas monitoring point I6 is as Figure 2As shown in the figure. Three measuring points are set on the side close to the intake airway, and two measuring points are set on the return airway side. Measuring points ①#, ②#, and ③# are connected to the intake airway vacuum pump bundle tube gas sampling point as a group, and measuring points ④# and ⑤# are connected to the return airway vacuum pump bundle tube gas sampling point as a group. Measuring points ①# and ⑤# are set close to the coal pillar at the intake and return airways. The distance between measuring point ②# and measuring point ①# is 10 m, the distance between measuring point ③# and measuring point ②# is 20 m, and the distance between measuring point ④# and measuring point ⑤# is 20 m; observe the change of oxygen concentration in the gob area. The gob area bundle tube measuring point I6 is buried into the gob area as the working face advances continuously; the whole process of the bundle tube is protected by a 2-inch casing, and the casings are connected by flanges. The intake port of the gob area bundle tube is raised by about 1 m; the gob area bundle tube measuring point I6 is sampled and detected every two days. When the oxygen concentration measured by the bundle tube measuring point is lower than 18%, when the gob area begins to enter the oxidation zone, determine the width of the gob area at this time.

[0019] Step 2: As the working face advances, first, lay a L-shaped liquid injection pipeline 15 on one side of the intake airway 12. One end of the grouting pipeline is connected to the liquid injection pump 14 in the intake airway, and the other end of the liquid injection pipe is bent 90 degrees at the corner of the working face and then laid on the working face. The laying length is 2 m, and this section of the liquid injection pipe is a perforated pipe 17. The liquid injection pipeline is buried into the gob area as the working face advances.

[0020] Step 3: After the working face advances 10 m, lay a L-shaped liquid injection pipeline 3 on one side of the return airway 7. The laying method is the same as that in Step 2; set another bundle tube measuring point II4 at the corner of the working face in the intake airway. The bundle tube measuring point II and the liquid injection pipeline are buried into the gob area as the working face advances. The bundle tube measuring point II is connected to the pipeline of the vacuum pump bundle tube gas sampling point.

[0021] Step 4: After the working face advances another 10 m, continue to lay a L-shaped liquid injection pipeline on one side of the intake airway 12, and set the return airway bundle tube measuring point II16 at the corner of the working face in the return airway for the second time. The return airway bundle tube measuring point II16 and the liquid injection pipeline are buried into the gob area as the working face advances; as the working face advances continuously, repeat the layout methods of the liquid injection pipeline and the bundle tube measuring point in Step 3 and Step 4.

[0022] Step 5: As the working face advances continuously, repeat the layout of the L-shaped liquid injection pipeline and the bundle tube measuring point II in Steps 2 - 4;

[0023] Step 6: As the working face advances continuously, collect gas samples from the gob area bundle tube measuring point I6, the intake airway bundle tube measuring point II16, and the return airway bundle tube measuring point II4 once every two days, analyze them with a gas chromatograph, and record the daily advance of the working face. When the advancing distance of the working face meets the condition that the gob area begins to enter the oxidation zone, or determine that the gob area enters the oxidation zone by referring to the spontaneous combustion three-zone situation of the adjacent working face, or when the bundle tube measuring point measures the appearance of gases such as carbon monoxide and ethylene in the gob area, inject the microbial mixed bacterial liquid into the gob area.

[0024] The microorganisms include (Bacillus subtilis, yeast), and the culture medium is a common nutrient solution for microorganism culture. Additives such as inhibitors can be added under the condition of ensuring the oxygen-consuming activity of the microorganisms. In addition to using the liquid injection flower tubes 17 and 5 previously reserved in the intake and return air headings to carry out the grouting operation on the gob area, the gob area with high spontaneous combustion risk such as the caving zone, near the fault zone, and the coal loss location can also be grouted by drilling and grouting.

[0025] Step 7: After injecting the microbial mixed liquid, according to the bundle tube measuring points 16 and 4 reserved again in the intake and return air headings, the oxygen concentration in the gob area after injecting the microbial mixed liquid is analyzed in real time, and combined with the detection data of the bundle tube measuring point 6 at the cutting eye, the fire prevention and extinguishing effect of the gob area is analyzed. When the gas concentrations in the gob area are reduced to below the safety value, the injection is stopped. The spontaneous combustion three zones in the gob area after the action of the expected microbial green fire prevention and extinguishing technology are as Figure 3 shown. The ranges of the heat dissipation zone 9 and the oxidation zone 10 are greatly reduced, and the range of the asphyxiation zone 12 is increased.

[0026] Certainly, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by those skilled in the art within the essence of the present invention should also fall within the protection scope of the present invention.

Claims

1. A green fire prevention and extinguishing method for gob areas using microorganisms, characterized in that , the fire prevention and extinguishing method comprises the following steps: Step 1: Five bundle tube measuring points Ⅰ are unevenly arranged at the cutting face working face position. Two vacuum pump bundle tube gas sampling points are set at the intake airway and the return airway at a position not greater than 100 m from the cutting face working face. The bundle tube measuring points are connected to the vacuum pump bundle tube gas sampling points through pipelines. After the measuring points are buried in the gob area as the working face advances, continuously observe the change of oxygen concentration in the gob area to determine the width of the oxidation zone when the gob area begins to enter the oxidation zone in the spontaneous combustion three zones; Step 2: As the coal mining working face advances, a L-shaped liquid injection pipeline is reserved on one side of the intake airway. One end of the grouting pipeline is connected to the liquid injection pump in the intake airway, and the liquid injection pipe at the other end is bent 90 degrees along the coal seam dip at the working face corner and then laid into the working face. The liquid injection pipeline is buried in the gob area as the working face advances; Step 3: After the coal mining working face continues to advance by H / 2, a L-shaped liquid injection pipeline is reserved on the return airway side. The laying method is the same as that in Step 2. The first bundle tube measuring point Ⅱ is set at the working face corner of the intake airway. The first bundle tube measuring point Ⅱ is connected to the vacuum pump bundle tube gas sampling point through a pipeline; Step 4: Repeat the operation in Step 2. A second L-shaped liquid injection pipeline is set in the intake airway. The second bundle tube measuring point Ⅱ is set at the working face corner of the return airway. The second bundle tube measuring point Ⅱ is connected to the vacuum pump bundle tube gas sampling point through a pipeline; Step 5: As the working face continuously advances, repeat the arrangement of the L-shaped liquid injection pipeline and the bundle tube measuring point Ⅱ in Steps 2-4; Step 6: According to the data of the bundle tube measuring point Ⅰ in Step 1, when the advancing distance of the working face satisfies that the gob area begins to enter the oxidation zone, or refer to the spontaneous combustion three zones of the adjacent working face to determine that the gob area enters the oxidation zone, or when the bundle tube measuring point measures carbon monoxide and ethylene gases in the gob area, mix microorganisms, culture medium, and additives to obtain a microbial mixed liquid and then transport it underground. Use the L-shaped liquid injection pipelines reserved in the intake airway and the return airway to inject the microbial mixed liquid into the gob area; Step 7: The coal mining working face continues to advance. Repeat the operation in Steps 2-4 to reserve the bundle tube measuring point Ⅱ and the L-shaped liquid injection pipeline again in the intake airway and the return airway, and analyze the oxygen concentration in the gob area in real time after injecting the microbial mixed liquid. Compare the data measured by the bundle tube measuring point Ⅱ in the gob area after injecting the microbial mixed liquid with the data measured by the bundle tube measuring point Ⅰ set in Step 1 to analyze the fire prevention and extinguishing effect of the gob area.

2. A green fire prevention and extinguishing method for gob areas using microorganisms according to claim 1, characterized in that, in Step 1, when the oxygen concentration measured by the bundle tube measuring point Ⅰ is lower than 18%, it is considered that the gob area begins to enter the oxidation zone, and the width of the oxidation zone in the gob area at this time is determined.

3. A green fire prevention and extinguishing method for gob areas using microorganisms according to claim 1, characterized in that, for the said L-shaped liquid injection pipeline, the length of the liquid injection pipe orifice end along the working face dip is 2 m, 5 m, 10 m after bending 90 degrees, and the liquid injection pipe along the working face dip section is a perforated pipe.

4. A green fire prevention and extinguishing method for gob areas using microorganisms according to claim 1, characterized in that, In Step 3, within the advancing distance H / 2 of the working face, depending on the spontaneous combustion risk level of the goaf, H is 10 m, 20 m, 30 m, or 40 m.

5. A microbial green fire prevention and extinguishing method for goafs according to claim 1, characterized in that in Step 6, the microbial strains are one or several of Bacillus subtilis, methanotrophs, and yeasts.

6. A microbial green fire prevention and extinguishing method for goafs according to claim 1, characterized in that in Step 6, in the microbial mixed bacterial liquid, the culture medium is anhydrous glucose, peptone, yeast extract, potassium dihydrogen phosphate, calcium carbonate, inorganic salt medium, and trace element solution. In addition to containing nutrients for the microorganisms, other additives that do not affect the survival of the microorganisms and are beneficial to inhibiting coal spontaneous combustion can be added under the condition of ensuring the oxygen-consuming activity of the microorganisms.

7. A microbial green fire prevention and extinguishing method for goafs according to claim 1, characterized in that in Step 6, in addition to using the pre-reserved liquid injection pipeline to carry out pressure injection operations on the goaf, the microbial mixed bacterial liquid can also be injected into some areas with high spontaneous combustion risks, such as the caving zone of the goaf, near the fault zone, and the coal loss location, by means of construction drilling and pressure injection.

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