Method and system for preventing and extinguishing fire in up-down combined goaf

Abstract

The invention provides a fire preventing and extinguishing method and system for an up-down combined goaf, and relates to the technical field of underground coal mine safety control. The method comprises the following steps: drilling a coal rock layer towards the goaf on the ground surface, arranging an up-down fire preventing and extinguishing material source on the ground surface, and connecting a first conveying pipe, at least part of the first conveying pipe is laid in the drill hole, an underground fire preventing and extinguishing material source is installed at the position, close to the goaf, of the underground roadway, the underground fire preventing and extinguishing material source is connected with a second conveying pipe, and the second conveying pipe is laid in the underground roadway; the first valve and the second valve are opened, the above-well fire preventing and extinguishing material source pours fire preventing and extinguishing materials into the goaf through the first conveying pipe in the height direction, the third valve and the fourth valve are opened, and the underground fire preventing and extinguishing material source pours fire preventing and extinguishing materials into the underground roadway adjacent to the goaf through the second conveying pipe. Three-dimensional fire preventing and extinguishing pouring of the goaf can be achieved, and the fire preventing and extinguishing effect and efficiency are ensured.

Description

Technical Field

[0001] The invention relates to the technical field of underground safety prevention and control in coal mines, and in particular to a method and system for preventing and extinguishing fire in goaf areas in both underground and underground mines. Background Art

[0002] Some mines have the characteristics of shallow burial depth and close-range coal seam groups. The coal seams are nearly horizontal. After mining, large-scale multi-layer composite goafs are formed. The cracks communicate up and down and even reach the surface. The leakage process of multi-layer composite goafs, such as leakage in the layer, leakage between layers and leakage on the surface, tends to be complicated. Under the conditions of close spacing between coal seams, large goafs, many working face tunnels, closed tunnels, and masonry materials that are prone to fracturing under the action of mine pressure, it is difficult to grasp the leakage law. Oxidation self-heating high-temperature points may appear in the entire mine field. When spontaneous combustion occurs, there is often more than one high-temperature point, but multiple locations produce spontaneous combustion of coal at the same time or successively, affecting the safe mining of coal mines.

[0003] Among the related technologies, fire prevention and extinguishing technologies mainly include grouting, nitrogen, gel injection, inhibitor, pressure equalization, foam, and high polymer material plugging and wind fire prevention and extinguishing, etc. However, the above-mentioned fire prevention and extinguishing technologies have defects such as long fire extinguishing cycle, high cost, low efficiency, easy to reignite, long time to clean up the working surface after fire extinguishing, and some fire prevention and extinguishing technologies have the disadvantages of damaging underground facilities, resulting in strong limitations in actual application. Summary of the invention

[0004] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0005] To this end, an embodiment of one aspect of the present invention proposes a method for joint fire prevention and extinguishing in goaf areas above and below the well, which can realize three-dimensional fire prevention and extinguishing perfusion in the goaf, ensuring the fire prevention and extinguishing effect and efficiency.

[0006] Another embodiment of the present invention provides a combined above-and-below goaf fire prevention and extinguishing system.

[0007] A method for preventing and extinguishing fire in a goaf area in a well in combination with an upper and lower well according to an embodiment of the present invention comprises the following steps:

[0008] Drilling a hole in the coal rock layer on the surface in the direction of the goaf, laying an aboveground fire extinguishing material source on the surface and connecting it to a first delivery pipe, so that at least a portion of the first delivery pipe is laid in the drill hole, and installing an underground fire extinguishing material source in an underground tunnel adjacent to the goaf, so that the underground fire extinguishing material source is connected to a second delivery pipe, wherein the second delivery pipe is laid in the underground tunnel;

[0009] Open the first valve and the second valve, and the above-ground fire extinguishing material source injects fire extinguishing material into the goaf along the height direction through the first delivery pipe, and open the third valve and the fourth valve, and the underground fire extinguishing material source injects fire extinguishing material into the underground tunnel adjacent to the goaf through the second delivery pipe.

[0010] According to the above-ground combined goaf fire prevention and extinguishing method of the embodiment of the present invention, the above-ground fire prevention and extinguishing material source, the first conveying pipe and the borehole cooperate to form a system for injecting fire prevention and extinguishing materials from the surface to the top of the goaf, while the underground fire prevention and extinguishing material source and the second conveying pipe can inject the surrounding side of the goaf in the underground tunnel. The combination of the two allows the formed inerting belt to cover the goaf more three-dimensionally, eliminating the hidden dangers of fire in the overlying goaf and the coal seam, which may easily affect the mining of the coal seam and the underlying coal. The technical method is used to achieve the goal of preventing the spontaneous combustion of coal left in the goaf, and the injection amount of fire prevention and extinguishing materials can be effectively controlled. The overall method is simple to operate, safe and reliable, and has good effects, shortening the fire prevention and extinguishing cycle. Therefore, compared with related technologies, the present application can achieve three-dimensional fire prevention and extinguishing injection of the goaf, ensuring the fire prevention and extinguishing effect and efficiency.

[0011] In some embodiments, at least one of the above-ground fire extinguishing material source and the underground fire extinguishing material source is a liquid carbon dioxide source, so that the goaf can be extinguished by liquid carbon dioxide.

[0012] In some embodiments, the above-ground fire extinguishing material source and the underground fire extinguishing material source both include a storage tank, the storage tank is filled with liquid carbon dioxide and has a liquid phase outlet and a gas phase outlet, the liquid phase outlet is suitable for supplying liquid carbon dioxide, and the gas phase outlet is suitable for supplying gaseous carbon dioxide;

[0013] The liquid phase outlet and gas phase outlet of the above-ground fire extinguishing material source are both controlled on and off by the first valve, and the liquid phase outlet and gas phase outlet of the underground fire extinguishing material source are both controlled on and off by the third valve.

[0014] In some embodiments, before the steps of opening the first valve and the second valve, the fire extinguishing material source above the well injecting the fire extinguishing material into the goaf in the height direction through the first delivery pipe, and opening the third valve and the fourth valve, the fire extinguishing material source below the well injecting the fire extinguishing material into the underground tunnel adjacent to the goaf through the second delivery pipe, the method further comprises:

[0015] Performing an air tightness check on the first delivery pipe; and / or

[0016] Perform air tightness check on the second delivery pipe.

[0017] In some embodiments, the first valve is a three-way valve, and the step of checking the air tightness of the first delivery pipe includes:

[0018] Opening the first valve and the second valve, so that the gas phase outlet of the fire extinguishing material source on the well is connected to the first delivery pipe, so as to introduce gaseous carbon dioxide into the first delivery pipe for a first set time;

[0019] closing the second valve until the pressure of the first delivery pipe rises to a set pressure, closing the first valve, and maintaining the pressure of the first delivery pipe for a second set time;

[0020] The air tightness of the first delivery pipe is determined based on the monitoring data of the pressure sensor, the temperature sensor, the flow sensor and the carbon dioxide sensor.

[0021] In some embodiments, the step of opening the first valve and the second valve and injecting the fire extinguishing material into the fire zone along the height direction through the first delivery pipe by the source of fire extinguishing material on the well is to open the first valve and the second valve so that the liquid phase outlet of the source of fire extinguishing material on the well is connected with the first delivery pipe, and the first delivery pipe maintains the set pressure to inject liquid carbon dioxide into the goaf.

[0022] In some embodiments, after the steps of opening the first valve and the second valve, the fire extinguishing material source above the well injecting the fire extinguishing material into the goaf in the height direction through the first delivery pipe, and opening the third valve and the fourth valve, the fire extinguishing material source below the well injecting the fire extinguishing material into the underground tunnel adjacent to the goaf through the second delivery pipe, the method further comprises:

[0023] When the content of carbon dioxide in the air flow of the fully mechanized mining face exceeds the first set limit, and / or when the pressure of the first delivery pipe drops to the pressure limit, the first valve and the second valve are closed, and the first delivery pipe stops injecting liquid carbon dioxide;

[0024] When the oxygen concentration in either the return air corner or the comprehensive mining working face is not higher than the second set limit, the third valve and the fourth valve are closed, and the second delivery pipe stops injecting liquid carbon dioxide.

[0025] In some embodiments, the first valve is a three-way valve, and after the step of stopping the injection of liquid carbon dioxide into the first delivery pipe, the method further comprises:

[0026] Open the first valve and the second valve to connect the gas phase outlet of the fire extinguishing material source on the well to the first delivery pipe, and introduce gaseous carbon dioxide into the first delivery pipe for a third set time;

[0027] The first valve and the second valve are closed to complete the purging and ventilation of the first delivery pipe.

[0028] In some embodiments, the portion of the second delivery pipe that is away from the underground fire extinguishing material source extends to the oxidation and warming zone of the comprehensive mining working face to infuse liquid carbon dioxide into the oxidation and warming zone.

[0029] In some embodiments, there are two third valves, one of which is installed at the gas phase outlet of the underground fire extinguishing material source, and the other third valve is installed at the liquid phase outlet of the underground fire extinguishing material source;

[0030] The step of opening the third valve and the fourth valve, and injecting the fire extinguishing material from the underground fire extinguishing material source into the underground tunnel adjacent to the goaf through the second delivery pipe comprises:

[0031] Opening the third valve of the gas phase outlet of the underground fire extinguishing material source, and introducing gaseous carbon dioxide into the second delivery pipe;

[0032] When the pressure of the second delivery pipe is balanced with the pressure of the storage tank in the underground fire extinguishing material source, the third valve of the liquid phase outlet of the underground fire extinguishing material source is opened to a set opening. After the liquid carbon dioxide introduced into the second delivery pipe flows evenly, the third valve of the liquid phase outlet of the underground fire extinguishing material source is fully opened to inject liquid carbon dioxide into the oxidation warming zone.

[0033] According to an embodiment of the present invention, a combined above-and-below goaf fire prevention and extinguishing system comprises a borehole, an above-ground fire prevention and extinguishing material source, a first delivery pipe, an underground fire prevention and extinguishing material source and a second delivery pipe, the borehole extending in a direction from the ground surface toward an adjacent goaf, and the borehole is connected to the goaf; the above-ground fire prevention and extinguishing material source is located on the ground surface and is connected to a first end of the first delivery pipe through a first valve, at least a portion of the first delivery pipe is installed in the borehole, and a second end of the first delivery pipe is connected to the borehole through a second valve; the underground fire prevention and extinguishing material source is located in an underground tunnel adjacent to the goaf and is connected to a first end of the second delivery pipe through a third valve, the second delivery pipe is installed in the underground tunnel, and a second end of the second delivery pipe is connected to the underground tunnel through a fourth valve.

[0034] The technical advantages of the above-and-below combined goaf fire prevention and extinguishing system according to the embodiment of the present invention are the same as the technical advantages of the above-and-below combined goaf fire prevention and extinguishing method, which will not be repeated here.

[0035] In some embodiments, the first end and the second end of the first delivery pipe are both provided with at least one of a pressure sensor, a temperature sensor and a flow sensor.

[0036] In some embodiments, a carbon dioxide sensor is disposed on the first delivery pipe, and there are a plurality of carbon dioxide sensors arranged at intervals along an extension direction of the first delivery pipe.

[0037] In some embodiments, the fire protection and extinguishing system further comprises an oxygen sensor, which is installed at at least one of the return air corner and the comprehensive mining working face.

[0038] In some embodiments, the fire prevention and extinguishing system also includes a mine monitoring unit and a main control unit. The mine monitoring unit is connected to the first valve, the second valve, the pressure sensor, the temperature sensor, the flow sensor, the carbon dioxide sensor and the oxygen sensor through an optical cable, and the main control unit is connected to the mine monitoring unit through a cable.

[0039] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a flow chart of a method for joint fire prevention and extinguishing in goaf areas above and below a well according to an embodiment of the present invention.

[0041] Figure 2 It is a flow chart of a method for joint fire prevention and extinguishing in goaf areas above and below a well according to another embodiment of the present invention.

[0042] Figure 3 It is a schematic flow chart of the air tightness inspection of the first conveying pipe in the method for joint fire prevention and extinguishing of goaf areas in a well according to an embodiment of the present invention.

[0043] Figure 4 It is a flow chart of a method for joint fire prevention and extinguishing in goaf areas above and below a well according to yet another embodiment of the present invention.

[0044] Figure 5 It is a flow chart of a method for joint fire prevention and extinguishing in goaf areas above and below a well according to another embodiment of the present invention.

[0045] Figure 6 It is a schematic diagram of the injection structure of the goaf by the drilling hole, the up-and-down combined goaf fire prevention and extinguishing system, and the first conveying pipe according to an embodiment of the present invention.

[0046] Reference numerals:

[0047] 1. Borehole, 2. Source of fire-fighting materials above the well, 3. First delivery pipe, 4. Goaf. DETAILED DESCRIPTION

[0048] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0049] like Figure 1 As shown, a method for preventing and extinguishing fire in a goaf area in a well in an embodiment of the present invention comprises the following steps:

[0050] Step S1, constructing a borehole 1 on the surface in the direction of the coal rock layer toward the goaf 4, laying an aboveground fire extinguishing material source 2 on the surface and connecting it to a first delivery pipe 3, so that at least a portion of the first delivery pipe 3 is laid in the borehole 1, and installing an underground fire extinguishing material source in an underground tunnel adjacent to the goaf 4, so that the underground fire extinguishing material source is connected to a second delivery pipe, wherein the second delivery pipe is laid in the underground tunnel;

[0051] Step S2, open the first valve and the second valve, the surface fire extinguishing material source 2 injects fire extinguishing material into the goaf 4 along the height direction through the first conveying pipe 3, and open the third valve and the fourth valve, the underground fire extinguishing material source injects fire extinguishing material into the underground tunnel adjacent to the goaf 4 through the second conveying pipe.

[0052] It can be understood that according to the above-ground combined goaf fire prevention and extinguishing method of the embodiment of the present invention, the above-ground fire prevention and extinguishing material source 2, the first conveying pipe 3 and the borehole 1 cooperate to form a fire prevention and extinguishing material system for injecting the upper part of the goaf 4 from the surface, while the underground fire prevention and extinguishing material source and the second conveying pipe can inject the surrounding side of the goaf 4 in the underground tunnel. The combination of the two allows the formed inerting belt to cover the goaf 4 more three-dimensionally, eliminating the hidden dangers of fire in the overlying goaf 4 and the coal seam, which may easily affect the mining of the coal seam and the underlying coal. The technical method is used to achieve the goal of preventing the spontaneous combustion of the coal left in the goaf 4, and the injection amount of the fire prevention and extinguishing material can be effectively controlled. The overall method is simple to operate, safe and reliable, and has good effects, shortening the fire prevention and extinguishing cycle. Therefore, compared with the relevant technology, the present application can achieve three-dimensional fire prevention and extinguishing injection of the goaf 4, ensuring the fire prevention and extinguishing effect and efficiency.

[0053] Specifically, the borehole 1 may extend from the surface to the goaf 4. The first delivery pipe 3 may extend along the extension direction of the borehole 1. The second delivery pipe may extend along the extension direction of the underground tunnel. The height direction may be the up and down direction in the figure. The end of the first delivery pipe 3 away from the above-ground fire extinguishing material source 2 may extend to the goaf 4. The fire extinguishing material may not be limited to materials with fire extinguishing properties such as inert gas, slurry, gel, and inhibitor.

[0054] Preferably, the borehole 1 is arranged closer to the fire zone of the goaf 4 (the fire zone is the fire area in the goaf 4). The end of the second delivery pipe away from the underground fire extinguishing material source is arranged in an underground tunnel closer to the fire zone of the goaf 4.

[0055] like Figure 1As shown, in some embodiments, at least one of the aboveground fire extinguishing material source 2 and the underground fire extinguishing material source is a liquid carbon dioxide source, so as to extinguish the fire in the goaf 4 by liquid carbon dioxide.

[0056] It can be understood that the use of liquid carbon dioxide to prevent and control spontaneous combustion fires in goaf 4 can make full use of the low temperature and inert properties of carbon dioxide to quickly and effectively cool and inert the coal body. At the same time, carbon dioxide has a large density and relatively poor fluidity. The gas can remain in goaf 4 for a long time, and the inerting effect on goaf 4 is relatively long. In addition, since coal has a super strong adsorption capacity for carbon dioxide, it can also effectively prevent oxygen from contacting coal. Therefore, the use of carbon dioxide as an injection material has a good fire prevention and extinguishing effect, and has incomparable advantages over other fire prevention and extinguishing technologies.

[0057] like Figure 1 As shown, in some embodiments, the above-ground fire extinguishing material source 2 and the underground fire extinguishing material source both include storage tanks filled with liquid carbon dioxide and having a liquid phase outlet and a gas phase outlet, the liquid phase outlet is suitable for supplying liquid carbon dioxide, and the gas phase outlet is suitable for supplying gaseous carbon dioxide.

[0058] The liquid phase outlet and gas phase outlet of the aboveground fire extinguishing material source 2 are both controlled by the first valve, and the liquid phase outlet and gas phase outlet of the underground fire extinguishing material source are both controlled by the third valve.

[0059] It can be understood that storing liquid carbon dioxide in a storage tank makes it easier for the surface fire extinguishing material source 2 and the underground fire extinguishing material source to move closer to the goaf 4 or its fire zone to further improve the fire prevention and extinguishing efficiency. At the same time, because the storage tank is provided with a liquid phase outlet and a gas phase outlet, the discharge method of the fire extinguishing material can be selected according to actual needs to meet the use requirements, and the integrated arrangement of the liquid carbon dioxide source and the gaseous carbon dioxide source is also realized, reducing space occupancy.

[0060] It should be noted that the storage tank of the fire extinguishing material source 2 on the well can be installed on a tank truck, which can be used to quickly adjust the position of the storage tank relative to the goaf 4. The liquid phase outlet and the gas phase outlet of the storage tank can be connected to the two inlets of the ground three-way gate valve through a metal hose. The outlet of the three-way gate valve can be connected to the inlet of the ground electric regulating valve through a short conveying pipe. The inlet of the ground electric regulating valve is connected to the inlet of the long-distance conveying pipe. The long-distance conveying pipe is laid along the surface through the borehole 1 to the underground injection area. The outlet of the long-distance conveying pipe is connected to the inlet of the second valve (such as the underground electric regulating valve), and the metal hose is connected to the outlet of the second valve as the output end of the liquid carbon dioxide. Among them, the three-way gate valve and the ground electric regulating valve can cooperate to form the first valve of the present invention, and the long-distance conveying pipe is equivalent to the first conveying pipe 3 of the present invention.

[0061] In addition, the structure of the underground fire extinguishing material storage tank can be basically the same as that of the large liquid storage tank, using an inner and outer double-layer tank structure, with the net volume of the inner tank being 2m 3 , can hold 2 tons of liquid carbon dioxide, which is filled with liquid carbon dioxide on the ground through a large liquid storage tank by a special underground tank train, and then transported to the vicinity of the fire zone of the goaf 4 by a flatbed mine car, so that the liquid carbon dioxide is directly injected into the underground tunnel or fire zone for fire prevention and extinguishing. At the same time, after the underground fire prevention and extinguishing material source storage tank is transported to the place, it must be stabilized first to prevent the equipment from vibrating and causing dangers and affecting the service life of the equipment due to the fast flow rate and high pressure of liquid carbon dioxide. Among them, the liquid phase outlet and gas phase outlet of the underground fire prevention and extinguishing material source storage tank can be connected to the inlet of a valve (that is, the third valve) respectively to control the opening and closing of the liquid phase outlet and the gas phase outlet respectively, and the outlet of the valve can be connected to the joint lane closed wall measure hole or the rubber transport chute pre-buried pipe (that is, the second conveying pipe in the present invention) within the oxidation and heating zone of the auxiliary transportation chute of the comprehensive mining working face through a high-pressure hose, so as to prevent and extinguish the goaf 4 of the comprehensive mining working face through the measure hole or pre-buried pipe.

[0062] like Figure 2 As shown, in some embodiments, before step S2, the method further includes:

[0063] Step S1', performing an airtightness check on the first delivery pipe 3; and / or

[0064] Step S1", performing an air tightness test on the second delivery pipe, wherein when performing an air tightness test on the storage tank of the underground fire extinguishing material source and the second delivery pipe, the test pressure may be, for example, 2.65 MPa.

[0065] It is understandable that the air tightness check can ensure the smooth progress of the perfusion process and avoid pipeline leakage that endangers personal safety.

[0066] like Figure 3 As shown, in some embodiments, the first valve is a three-way valve, wherein the two inlets of the first valve are respectively connected to the liquid phase outlet and the gas phase outlet of the storage tank of the well fire extinguishing material source 2 in a one-to-one correspondence, and the outlet of the first valve is connected to the inlet of the first delivery pipe 3. The step of checking the air tightness of the first delivery pipe 3 includes:

[0067] Step S1'1, open the first valve and the second valve, so that the gas phase outlet of the well fire extinguishing material source 2 is connected to the first delivery pipe 3, so as to introduce gaseous carbon dioxide into the first delivery pipe 3 for a first set time, wherein the first set time can be, for example, 10 minutes, and the gas in the first delivery pipe 3 is treated, purged and ventilated with gaseous carbon dioxide;

[0068] Step S1'2, close the second valve until the pressure of the first delivery pipe 3 rises to the set pressure, close the first valve, and maintain the pressure of the first delivery pipe 3 for a second set time, wherein the set pressure can be 1.8 MPa to 2.0 MPa, and the second set time can be, for example, 20 minutes;

[0069] Step S1'3, judging the air tightness of the first delivery pipe 3 according to the monitoring data of the pressure sensor, the temperature sensor, the flow sensor and the carbon dioxide sensor.

[0070] like Figure 1 As shown, in some embodiments, the first valve and the second valve are opened, and the step of injecting the fire extinguishing material into the fire zone along the height direction through the first delivery pipe 3 by the fire extinguishing material source 2 on the well is as follows: the first valve and the second valve are opened to connect the liquid phase outlet of the fire extinguishing material source 2 on the well with the first delivery pipe 3, and based on the detection data of the pressure sensor, the temperature sensor and the flow sensor, the opening of the second valve is controlled so that the first delivery pipe 3 maintains the set pressure to inject liquid carbon dioxide into the goaf 4, thereby realizing long-distance pressure-maintaining transportation of liquid carbon dioxide.

[0071] like Figure 4 As shown, in some embodiments, after step S2, the method further includes:

[0072] Step S3, when the content of carbon dioxide in the air flow of the fully mechanized mining face exceeds a first set limit (wherein, the first set limit is, for example, when the content of carbon dioxide accounts for 0.5% of the total gas volume of the air flow of the air flow, and in addition, the setting of limits in other areas may refer to the relevant regulations on coal mine safety), and / or, when the pressure of the first delivery pipe 3 drops to the pressure limit (for example, the pressure limit of the first delivery pipe 3 is set to 0 MPa), the first valve and the second valve are closed, and the first delivery pipe 3 stops infusing liquid carbon dioxide;

[0073] Step S3', when the oxygen concentration in any one of the return air corner and the fully mechanized mining face is not higher than the second set limit (wherein the second set limit may be, for example, 18.5% oxygen concentration), close the third valve and the fourth valve, and stop injecting liquid carbon dioxide into the second delivery pipe.

[0074] It should be noted that if the oxygen concentration in the return air corner drops to 18.5% or below, shut down the underground fire-fighting material source and the second delivery pipe to stop the injection of liquid carbon dioxide. If the oxygen concentration at the working face drops to 18.5% or below, immediately evacuate all personnel at the working face, report to the dispatch room, shut down the underground fire-fighting material source and the second delivery pipe to stop the injection of liquid carbon dioxide.

[0075] like Figure 5As shown, in some embodiments, the first valve is a three-way valve, and after the step of stopping the injection of liquid carbon dioxide into the first delivery pipe 3, the method further comprises:

[0076] Step S4, opening the first valve and the second valve, so that the gas phase outlet of the well fire extinguishing material source 2 is connected to the first delivery pipe 3, and the gaseous carbon dioxide for a third set time is introduced into the first delivery pipe 3, wherein the third set time can be, for example, 10 minutes;

[0077] Step S5, closing the first valve and the second valve to complete the purging and ventilation of the first delivery pipe 3.

[0078] It can be understood that, according to step S4 and step S5, after the direct injection of liquid carbon dioxide is completed, gaseous carbon dioxide can be used to treat the gas in the first delivery pipe 3 to ensure that the first delivery pipe 3 is not blocked by dry ice, thereby completing the cleaning of the first delivery pipe 3.

[0079] like Figure 6 As shown, in some embodiments, the portion of the second delivery pipe away from the underground fire extinguishing material source extends to the oxidation and warming zone of the comprehensive mining working face to infuse liquid carbon dioxide into the oxidation and warming zone.

[0080] In some embodiments, there are two third valves, one of which is installed at the gas phase outlet of the underground fire extinguishing material source, and the other third valve is installed at the liquid phase outlet of the underground fire extinguishing material source.

[0081] The steps of opening the third valve and the fourth valve, and injecting the fire extinguishing material from the underground fire extinguishing material source into the underground tunnel adjacent to the goaf 4 through the second delivery pipe include:

[0082] Step S21, when it is confirmed that the pressure in the storage tank of the underground fire extinguishing material source (>1.3MPa) reaches the injection requirement, the third valve of the gas phase outlet of the underground fire extinguishing material source can be opened to introduce gaseous carbon dioxide into the second delivery pipe. The gaseous carbon dioxide makes the pressure of the second delivery pipe above 1.3MPa to avoid the problem that the liquid carbon dioxide solidifies into dry ice and blocks the pipeline when the second delivery pipe directly enters the liquid carbon dioxide due to too low pressure, resulting in the failure of injection;

[0083] Step S22, the pressure in the second delivery pipe is balanced with the pressure in the storage tank of the underground fire extinguishing material source, the third valve of the liquid phase outlet of the underground fire extinguishing material source is opened to a set opening (for example, opened 1 / 2), and after the liquid carbon dioxide introduced into the second delivery pipe flows evenly, the third valve of the liquid phase outlet of the underground fire extinguishing material source is fully opened to inject liquid carbon dioxide into the oxidation heating zone.

[0084] In addition, after the second delivery pipe is filled, the third valve of the liquid phase outlet and the gas phase outlet of the storage tank in the underground fire extinguishing material source can be closed first, and then the fourth valve (that is, the valve on the measure hole or the embedded pipe) can be closed, and finally the vent valve can be opened to vent the pressure in the second delivery pipe. The second delivery pipe can be disassembled only when the joints at both ends of the second delivery pipe can be loosened by hand. When disassembling the second delivery pipe, the staff must wear gloves to prevent frostbite caused by freezing of the second delivery pipe.

[0085] It should be noted that, in some embodiments of the present invention, the method for preventing and extinguishing fire in the goaf area jointly above and below the well includes step S1 and step S2; in other embodiments, the method for preventing and extinguishing fire in the goaf area jointly above and below the well includes step S1, step S1', step S1", and step S2. It should be noted that, in this embodiment, there is no order limitation between step S1' and step S1"; in still other embodiments, the method for preventing and extinguishing fire in the goaf area jointly above and below the well includes step S1, step S1', step S1", step S2, step S3, and step S3'. It should be noted that, in this embodiment, there is no order limitation between step S1' and step S1", as well as step S3 and step S3'; in still other embodiments, the method for preventing and extinguishing fire in the goaf area jointly above and below the well includes step S1, step S1', step S1", step S2, step S3, step S3', step S4, and step S5. It should be noted that, in this embodiment, there is no order limitation between step S1' and step S1", as well as step S3 and step S3'. Therefore, the combined upper and lower goaf fire prevention and extinguishing methods of the present invention can be the above-mentioned four methods respectively.

[0086] In addition, the following inerting indicators must be met when injecting liquid carbon dioxide for fire prevention and extinguishing:

[0087] 1) When injecting liquid carbon dioxide into goaf 4, the concentration of injected liquid carbon dioxide should not be less than 97%;

[0088] 2) After the injection of liquid carbon dioxide, the inerting indicators of goaf 4 should meet the following requirements: a. The inerting oxygen concentration should not be greater than the critical oxygen concentration for spontaneous combustion of coal, and the oxygen content should not be greater than 7%; b. The inerting fire extinguishing oxygen concentration should not be greater than 3%; c. The inerting oxygen concentration for suppressing gas explosion should be less than 12%.

[0089] The injection flow rate of liquid carbon dioxide injected into the underground fire extinguishing material source and the second delivery pipe per hour in the present invention, and the actual amount of carbon dioxide required by the goaf 4 when the fire extinguishing effect is achieved according to different standards are calculated, as follows:

[0090] 1. Calculation of the hourly injection rate of liquid carbon dioxide into the underground fire extinguishing material source and the second delivery pipe

[0091] The flow rate of liquid carbon dioxide injected for mine fire prevention is subject to various factors, and is determined in accordance with the "Code for Fire Prevention Design of Coal Mine" in the present invention.

[0092] The daily injection volume for fire prevention can be calculated according to the air leakage volume and oxygen concentration. The calculation formula is as follows:

[0093]

[0094] In the formula, - Liquid carbon dioxide injection volume in oxidation warming zone, m 3 / h;

[0095] q- air leakage in the oxidation heating zone, for example, 10m 3 / min;

[0096] C1- the original average oxygen concentration in the oxidation warming zone, for example, 14%;

[0097] C2-inert oxygen concentration in the oxidation heating zone, for example, 8%;

[0098] K-reserve coefficient, for example, 1.1.

[0099] Substituting the above parameters into the formula, we get:

[0100]

[0101] That is to say, it has been calculated that the injection rate of liquid carbon dioxide from the underground fire extinguishing material source and the second delivery pipe is 1 t / h per hour.

[0102] 2. Calculation method of carbon dioxide injection volume for mine fire prevention and extinguishing

[0103] 1) Calculation of carbon dioxide consumption in goaf 4 fire prevention

[0104] a. Calculated by output:

[0105] q=Ar·t·η1η2C1C2-1

[0106] Where, q is the carbon dioxide injection intensity, m 3 / h; A-annual output, 10,000 tons; r-density of coal, t / m 3 ; η1- pipeline transportation efficiency, which can be taken as 0.9; η2- goaf area 4 inerting efficiency, which can be taken as 0.55; C1- oxygen concentration contained in the air, which can be taken as 21%; C2- goaf area 4 fire extinguishing inerting index, the oxygen content is 5%.

[0107] b. Calculated by gas content:

[0108] q=60×Q 漏 (C1-C2-C3) / C3

[0109] Where, q is the carbon dioxide injection intensity, m 3 / h;Q 漏 - Air leakage in oxidation zone 4 of goaf, m 3 / h; C1-initial oxygen concentration in the oxidation zone 4 of the goaf; C2-content of gases such as carbon dioxide and methane in the oxidation zone 4 of the goaf; C3-oxygen content specified by the inerting index of the oxidation zone 4 of the goaf, which can be taken as 10%.

[0110] c. Calculated based on the average amount of carbon dioxide injected per ton of coal:

[0111] q=q 注 ·H·m·L·γ·C / 24

[0112] Where, q is the carbon dioxide injection intensity, m 3 / h;q 注 -ton coal injection amount, take q 注 =6m 3 / t; H-length of coal mining face, m; L-daily advancement of mining face, m / d; m-average thickness of coal seam, m; γ-bulk density of coal, t / m 3 ; C-working face recovery rate.

[0113] 2) Carbon dioxide consumption in fire extinguishing area

[0114] Fire zone volume calculation:

[0115] Q=W·H·L·K1·K2

[0116] Among them, Q is the amount of inert gas injected; W is the width of the inerting zone; H is the height of the inerting zone; L is the length of the inerting zone; K1 is the replacement coefficient of the fire zone gas; K2 is the backup coefficient.

[0117] It should be noted that the parameters of the inerting zone can be monitored by the bundle tube monitoring system. When conducting fire prevention, the actual amount of carbon dioxide injection required in goaf 4 must be above the amount required by any of the above calculation methods; when conducting fire extinguishing, the actual amount of carbon dioxide injection required in goaf 4 must be above the amount required by the above fire zone calculation method. Scientifically divide the scope of liquid carbon dioxide injection, reasonably determine the liquid carbon dioxide injection area, realize on-demand injection, optimize the regional liquid carbon dioxide injection process above and below the well, and solve the problem of long-distance transportation of injection pipelines.

[0118] like Figure 6As shown, an embodiment of the present invention is a combined above-and-below goaf fire prevention and extinguishing system, comprising a borehole 1, an above-ground fire prevention and extinguishing material source 2, a first delivery pipe 3, an underground fire prevention and extinguishing material source and a second delivery pipe (not shown in the figure), the borehole 1 extends in a direction from the surface toward an adjacent goaf 4, and the borehole 1 is connected to the goaf 4; the above-ground fire prevention and extinguishing material source 2 is located on the surface and is connected to a first end of the first delivery pipe 3 through a first valve, at least a portion of the first delivery pipe 3 is installed in the borehole 1, and a second end of the first delivery pipe 3 is connected to the borehole 1 through a second valve; the underground fire prevention and extinguishing material source is located in an underground tunnel adjacent to the goaf 4 and is connected to a first end of the second delivery pipe through a third valve, the second delivery pipe is installed in the underground tunnel, and a second end of the second delivery pipe is connected to the underground tunnel through a fourth valve.

[0119] The technical advantages of the above-and-below combined goaf fire prevention and extinguishing system according to the embodiment of the present invention are the same as the technical advantages of the above-and-below combined goaf fire prevention and extinguishing method, which will not be repeated here.

[0120] In some embodiments, the first end and the second end of the first delivery pipe 3 are both provided with at least one of a pressure sensor, a temperature sensor and a flow sensor (not shown in the figure).

[0121] Specifically, the first end of the first delivery pipe 3 corresponds to the inlet of the first delivery pipe 3 , and the second end of the first delivery pipe 3 corresponds to the outlet of the first delivery pipe 3 .

[0122] In some embodiments, a carbon dioxide sensor is disposed on the first delivery pipe 3 , and there are multiple carbon dioxide sensors arranged at intervals along the extension direction of the first delivery pipe 3 (not shown in the figure).

[0123] In some embodiments, the fire protection and extinguishing system further includes an oxygen sensor, which is installed at at least one of the return air corner and the comprehensive mining working face (not shown in the figure).

[0124] In some embodiments, the fire prevention and extinguishing system also includes a mine monitoring unit and a main control unit. The mine monitoring unit is connected to the first valve, the second valve, the pressure sensor, the temperature sensor, the flow sensor, the carbon dioxide sensor and the oxygen sensor through an optical cable, and the main control unit is connected to the mine monitoring unit through a cable to realize automatic control of the above-ground fire prevention and extinguishing material source 2, the first delivery pipe 3, the underground fire prevention and extinguishing material source and the second delivery pipe (not shown in the figure).

[0125] Specifically, the mining monitoring unit may not be limited to a mining intrinsically safe monitoring substation. The first valve, the second valve, the pressure sensor, the temperature sensor, the flow sensor (such as an ultrasonic flow meter), the carbon dioxide sensor and the oxygen sensor are connected respectively by mining communication optical cables; the ground mining intrinsically safe monitoring substation is connected to the underground mining intrinsically safe monitoring substation by using communication cables; the underground mining intrinsically safe monitoring substation is connected to the underground optical fiber switch by using mining communication cables, and then jumped to the aboveground optical fiber switch, and the main control unit (i.e., the ground integrated control terminal) is connected to the aboveground optical fiber switch.

[0126] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0127] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0128] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0129] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0130] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0131] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for preventing and extinguishing fire in goaf areas in a well, characterized in that: The following steps are involved: Drilling a hole in the coal rock layer on the surface in the direction of the goaf, laying an aboveground fire extinguishing material source on the surface and connecting it to a first delivery pipe, so that at least a portion of the first delivery pipe is laid in the drill hole, and installing an underground fire extinguishing material source in an underground tunnel adjacent to the goaf, so that the underground fire extinguishing material source is connected to a second delivery pipe, wherein the second delivery pipe is laid in the underground tunnel; Open the first valve and the second valve, and the above-ground fire extinguishing material source injects fire extinguishing material into the goaf along the height direction through the first delivery pipe, and open the third valve and the fourth valve, and the underground fire extinguishing material source injects fire extinguishing material into the underground tunnel adjacent to the goaf through the second delivery pipe.

2. The method for preventing and extinguishing fire in the goaf area of ​​a well in combination with the above-and-below well according to claim 1 is characterized in that: At least one of the above-ground fire extinguishing material source and the underground fire extinguishing material source is a liquid carbon dioxide source, so that the liquid carbon dioxide can be used to extinguish the fire in the goaf.

3. The method for preventing and extinguishing fire in the goaf area of ​​a well in combination with the above-and-below well according to claim 2 is characterized in that: The above-ground fire-fighting material source and the underground fire-fighting material source both include a storage tank, which is filled with liquid carbon dioxide and has a liquid phase outlet and a gas phase outlet, wherein the liquid phase outlet is suitable for supplying liquid carbon dioxide, and the gas phase outlet is suitable for supplying gaseous carbon dioxide; The liquid phase outlet and gas phase outlet of the above-ground fire extinguishing material source are both controlled on and off by the first valve, and the liquid phase outlet and gas phase outlet of the underground fire extinguishing material source are both controlled on and off by the third valve.

4. The method for preventing and extinguishing fire in the goaf area of ​​a well in combination with the above-and-below mine according to claim 3 is characterized in that: Before the steps of opening the first valve and the second valve, the fire extinguishing material source above the well injecting the fire extinguishing material into the goaf in the height direction through the first delivery pipe, and opening the third valve and the fourth valve, the fire extinguishing material source below the well injecting the fire extinguishing material into the underground tunnel adjacent to the goaf through the second delivery pipe, the method further comprises: Performing an air tightness check on the first delivery pipe; and / or Perform air tightness check on the second delivery pipe.

5. The method for preventing and extinguishing fire in goaf areas in a well in combination with above and below ground according to claim 3 is characterized in that: After the steps of opening the first valve and the second valve, the fire extinguishing material source above the well injecting the fire extinguishing material into the goaf in the height direction through the first delivery pipe, and opening the third valve and the fourth valve, the fire extinguishing material source below the well injecting the fire extinguishing material into the underground tunnel adjacent to the goaf through the second delivery pipe, the method further comprises: When the content of carbon dioxide in the air flow of the fully mechanized mining face exceeds the first set limit, and / or when the pressure of the first delivery pipe drops to the pressure limit, the first valve and the second valve are closed, and the first delivery pipe stops injecting liquid carbon dioxide; When the oxygen concentration in either the return air corner or the comprehensive mining working face is not higher than the second set limit, the third valve and the fourth valve are closed, and the second delivery pipe stops injecting liquid carbon dioxide.

6. The method for preventing and extinguishing fire in goaf areas in a well in combination with above and below ground according to claim 5, characterized in that: The first valve is a three-way valve. After the step of stopping the injection of liquid carbon dioxide into the first delivery pipe, the method further comprises: Open the first valve and the second valve to connect the gas phase outlet of the fire extinguishing material source on the well to the first delivery pipe, and introduce gaseous carbon dioxide into the first delivery pipe for a third set time; The first valve and the second valve are closed to complete the purging and ventilation of the first delivery pipe.

7. The method for preventing and extinguishing fire in the goaf area of ​​a well in combination with the above-and-below mine according to claim 5 or 6, characterized in that: The portion of the second delivery pipe that is away from the underground fire extinguishing material source extends to the oxidation and warming zone of the comprehensive mining working face to infuse liquid carbon dioxide into the oxidation and warming zone.

8. A combined underground and underground goaf fire prevention and extinguishing system, characterized in that: include: A borehole extending from the ground surface toward an adjacent goaf and communicating with the goaf; an uphole fire extinguishing material source and a first delivery pipe, wherein the uphole fire extinguishing material source is located on the surface and is connected to a first end of the first delivery pipe through a first valve, at least a portion of the first delivery pipe is installed in the borehole, and a second end of the first delivery pipe is connected to the borehole through a second valve; as well as An underground fire extinguishing material source and a second delivery pipe, wherein the underground fire extinguishing material source is located in an underground tunnel adjacent to the goaf and is connected to the first end of the second delivery pipe through a third valve, the second delivery pipe is installed in the underground tunnel, and the second end of the second delivery pipe is connected to the underground tunnel through a fourth valve.

9. The above-and-below combined goaf fire prevention and extinguishing system according to claim 8 is characterized in that: The first end and the second end of the first delivery pipe are both provided with at least one of a pressure sensor, a temperature sensor and a flow sensor; And / or, the first delivery pipe is provided with a carbon dioxide sensor, and there are a plurality of carbon dioxide sensors arranged at intervals along the extension direction of the first delivery pipe.

10. The underground and underground combined goaf fire prevention and extinguishing system according to claim 8 or 9, characterized in that: It also includes an oxygen sensor, which is installed at at least one of the return air corner and the fully mechanized mining working face.

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