Circulating nitrogen injection cooling system capable of rapidly reducing temperature of fire area of closed goaf

Abstract

The utility model relates to the technical field of closed goaf fire zone temperature reduction, in particular to a circulating nitrogen injection cooling system for rapidly reducing the temperature of a closed goaf fire zone, which comprises a working face arranged at the front end of a goaf, the working face is communicated with an air inlet way and an air return way, and a measure way is arranged on one side of the goaf; a nitrogen loop is arranged between the measure roadway and the fire area of the goaf; one end of the nitrogen loop is connected with a nitrogen making machine; an outlet of the nitrogen making machine is connected with an air cooler; the other end of the nitrogen loop is connected with a vacuum pump; and the nitrogen making machine, the air cooler and the vacuum pump are arranged in the measure lane. And through the arrangement of the air cooler, the temperature of a fire area can be reduced while it is guaranteed that inert gas rapidly reduces the oxygen concentration of the fire area for fire extinguishing, the time for re-unsealing of the working face is shortened, and the working efficiency is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of temperature reduction in a fire zone of a closed goaf, and specifically discloses a circulating nitrogen injection cooling system for rapidly reducing the temperature of a fire zone of a closed goaf. Background Art

[0002] After the goaf of the coal mining face is sealed due to spontaneous combustion, the fire area is hidden and maintains high temperature continuously. At the same time, toxic and harmful gases such as carbon monoxide, carbon dioxide, and methane are generated and accumulated in the closed space. These gases are difficult to discharge quickly, which brings immeasurable risks to the subsequent safe unsealing of the working face. In order to effectively control the high-temperature area of ​​the goaf, quickly discharge toxic and harmful gases, and safely unseal the working face, it is very necessary to adopt rapid cooling technology.

[0003] At present, in the existing technology, the fire treatment methods for closed goaf mainly include grouting, inert gas fire extinguishing and chemical fire extinguishing, etc. These methods have certain limitations, such as grouting takes a long time to take effect and cannot completely eliminate the fire source; although inert gas fire extinguishing can quickly reduce the oxygen concentration in the fire area, it has limited effect on reducing the temperature and is costly; chemical fire extinguishing agents are costly and may pollute the environment. Utility Model Content

[0004] In view of the above-mentioned deficiencies in the prior art, the utility model provides a circulating nitrogen injection cooling system for rapidly reducing the temperature of the fire zone in a closed goaf, so as to solve the problem that although inert gas fire extinguishing can rapidly reduce the oxygen concentration in the fire zone, it has limited effect on reducing the temperature.

[0005] To achieve the above purpose, the technical solution of the utility model is:

[0006] A circulating nitrogen injection cooling system for rapidly reducing the temperature of a fire zone in a closed goaf includes a working face opened at the front end of the goaf, the working face is connected to an air inlet tunnel and a return air tunnel, and a measure tunnel is opened on one side of the goaf; a nitrogen loop is set between the measure tunnel and the fire zone of the goaf; a nitrogen generator is connected to one end of the nitrogen loop, and an air cooler is connected to the outlet of the nitrogen generator; a vacuum pump is connected to the other end of the nitrogen loop; the nitrogen generator, the air cooler and the vacuum pump are all set in the measure tunnel. Through the setting of the air cooler, the temperature of the fire zone can be rapidly cooled down while ensuring that the inert gas quickly reduces the oxygen concentration in the fire zone to extinguish the fire, thereby reducing the time for the working face to be unsealed again and improving work efficiency.

[0007] Preferably, the nitrogen loop includes a nitrogen inlet pipe and a nitrogen return pipe; one end of the nitrogen inlet pipe is connected to the outlet of the air cooler, and the other open end is set in the fire zone of the goaf; one end of the nitrogen return pipe is connected to the inlet of the vacuum pump, and the other open end is set in the fire zone of the goaf.

[0008] Preferably, the distance between the open end of the nitrogen inlet pipe and the open end of the nitrogen return pipe is ≤5m. While the nitrogen introduced into the nitrogen inlet pipe can cover the fire area, it is ensured that the nitrogen and toxic and harmful gases in the fire area can be extracted from the nitrogen return pipe.

[0009] Preferably, the distance between the end of the nitrogen inlet pipe away from the air cooler and the end of the nitrogen return pipe away from the vacuum pump is equal to 5m. While nitrogen and toxic and harmful gases in the fire zone can be extracted from the nitrogen return pipe, the nitrogen introduced by the nitrogen inlet pipe can cover the area of ​​the fire zone to the greatest extent.

[0010] Preferably, the extending direction of the measure tunnel is perpendicular to the working surface and parallel to the air inlet tunnel or the air return tunnel.

[0011] Preferably, the depth of the measure tunnel is smaller than the depth of the working surface, so that part of the heat can be discharged along the nitrogen return pipe.

[0012] Preferably, flow meters are provided on both the nitrogen inlet pipe and the nitrogen return pipe, so as to facilitate the control of the nitrogen flow entering the goaf to be consistent with the flow extracted by the vacuum pump.

[0013] Preferably, a gas concentration sensor and a temperature sensor are provided at the gas outlet of the vacuum pump to monitor the concentration and temperature of the high-temperature gas circulating in the fire zone of the goaf in real time, so as to judge the development trend of the fire zone.

[0014] The beneficial effects of the utility model are as follows: through the provision of the air cooler, the temperature of the fire zone can be quickly cooled while ensuring that the inert gas quickly reduces the oxygen concentration in the fire zone to extinguish the fire, thereby reducing the time for re-unsealing the working surface and improving work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the utility model or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0016] Figure 1 It is a three-dimensional structural schematic diagram of the utility model;

[0017] Figure 2 It is a schematic diagram of the top structure of the utility model.

[0018] Description of reference numerals:

[0019] 1-air inlet lane, 2-return air lane, 3-working face, 4-fire area, 5-goaf area, 6-measures lane, 7-nitrogen inlet pipe, 8-air cooler, 9-nitrogen generator, 10-vacuum pump, 11-nitrogen return pipe. DETAILED DESCRIPTION

[0020] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0021] like Figure 1-2 As shown, a circulating nitrogen injection cooling system for rapidly reducing the temperature of the fire zone in a closed goaf includes a working face 3 opened at the front end of the goaf 5, the working face 3 is connected with an air inlet tunnel 1 and a return air tunnel 2, and a measure tunnel 6 is opened on one side of the goaf 5; a nitrogen loop is arranged between the measure tunnel 6 and the fire zone 4 of the goaf 5; a nitrogen generator 9 is connected to one end of the nitrogen loop, and an air cooler 8 is connected to the outlet of the nitrogen generator 9; a vacuum pump 10 is connected to the other end of the nitrogen loop; the nitrogen generator 9, the air cooler 8 and the vacuum pump 10 are all arranged in the measure tunnel 6. Through the arrangement of the air cooler 8, the temperature of the fire zone 4 can be rapidly cooled down while ensuring that the inert gas rapidly reduces the oxygen concentration of the fire zone 4 to extinguish the fire, thereby reducing the time for the working face 3 to be unsealed again and improving the work efficiency.

[0022] In the above configuration, the nitrogen loop includes a nitrogen inlet pipe 7 and a nitrogen return pipe 11; one end of the nitrogen inlet pipe 7 is connected to the outlet of the air cooler 8, and the other end is open and arranged in the fire zone 4 of the goaf 5; one end of the nitrogen return pipe 11 is connected to the inlet of the vacuum pump 10, and the other end is open and arranged in the fire zone 4 of the goaf 5. The distance between the open end of the nitrogen inlet pipe 7 and the open end of the nitrogen return pipe 11 is equal to 5m. While nitrogen and toxic and harmful gases in the fire zone can be extracted by the nitrogen return pipe 11, the nitrogen introduced by the nitrogen inlet pipe 7 can cover the area of ​​the fire zone 4 to the greatest extent. The extension direction of the measure lane 6 is perpendicular to the working face 3 and parallel to the air inlet lane 1 or the return air lane 2. The depth of the measure lane 6 is set less than the depth of the working face 3, so that part of the heat can be discharged along the nitrogen return pipe 11. Flow meters are provided on the nitrogen inlet pipe 7 and the nitrogen return pipe 11 to facilitate the control of the nitrogen flow entering the goaf 5 and the flow extracted by the vacuum pump 10 to be consistent. A gas concentration sensor and a temperature sensor are provided at the outlet end of the vacuum pump 10. It is used to monitor the concentration and temperature of the high temperature gas circulated from the goaf 5 and the fire zone 4 in real time, so as to judge the development trend of the fire zone. In this embodiment, the nitrogen released by the nitrogen generator 9 reaches the industrial nitrogen purity, which is above 99.5%.

[0023] In this embodiment, the method for implementing circulating nitrogen injection cooling is as follows:

[0024] Step 1: According to the change of gas concentration in the fire zone 4 before the working face 3 is closed, a high-power directional drilling rig is used to drill a directional hole in the fire zone 4. A nitrogen inlet pipe 7 and a nitrogen return pipe 11 are set in the borehole. The distance between the end of the nitrogen inlet pipe 7 away from the air cooler 8 and the end of the nitrogen return pipe 11 away from the vacuum pump 10 is equal to 5m.

[0025] Step 2: The nitrogen generator 9 is connected to the air cooler 8 through a steel pipe, and is connected to a flow meter at the release port of the air cooler 8, and finally connected to the nitrogen pipe 7. The released flow is calculated according to the following formula:

[0026] QN=60×Q0×(C1-C2) / (Cn+C2-1);

[0027] Where:

[0028] QN—nitrogen injection flow, m 3 / h;

[0029] Q0—air leakage in goaf 5 and fire zone 4;

[0030] C1—average oxygen content in goaf 5 fire zone 4;

[0031] C2—inert index in goaf 5 fire zone 4, take 0.5%;

[0032] Cn—Nitrogen content in injected nitrogen shall not be less than 99.5%.

[0033] Step 3: Connect the vacuum pump 10's exhaust end to the flowmeter and connect it to the nitrogen return pipe 11. During the vacuum pump 10's exhaust process, ensure that the nitrogen injection flow rate is the same as the exhaust flow rate, and use a mining flame-retardant wind tube cloth to discharge the high-temperature toxic and harmful gases to the main return air lane;

[0034] Step 4: while forming a circulating nitrogen injection cooling airflow, a gas concentration sensor and a temperature sensor are arranged at the gas outlet of the vacuum pump 10 to monitor the O2 and CO concentrations and temperature of the fire zone 4 in the goaf 5 in real time, and judge the development trend of the fire zone 4;

[0035] The position of fire zone 4 is not fixed but develops dynamically. Once the fire spreads, directional holes can be drilled in the measure tunnel 6 to spread to the goaf 5 and fire zone 4, and nitrogen inlet pipe 7 and nitrogen return pipe 11 can be installed to cover the range of fire zone 4. At the same time, the nitrogen injection flow rate and the vacuum pump 10 exhaust flow rate are maintained basically the same to balance the internal air pressure of the goaf.

[0036] The utility model constructs directional drilling in the measure tunnel 6 toward the goaf 5, uses high-purity nitrogen to form a low-temperature circulating inert gas flow around the fire zone 4, inertizes and deoxygenates the environment around the fire zone 4, and at the same time, high-temperature toxic and harmful gases are discharged through the nitrogen return pipe 11. While balancing the internal pressure of the goaf 5, the temperature of the residual coal and surrounding rock around the local fire zone 4 is quickly reduced, providing favorable conditions for the safe unsealing of the working face 3. The utility model can achieve rapid cooling, safety and economy, prevent re-ignition, and effectively protect the life and property safety of mine workers.

[0037] The beneficial effects of this embodiment are:

[0038] 1. Improve fire extinguishing efficiency: By using low-temperature nitrogen to directly cool the fire source, the temperature of the fire zone 4 can be quickly reduced, effectively suppressing the spread of fire, thereby improving fire extinguishing efficiency.

[0039] 2. Safety and environmental protection: As an inert gas, nitrogen will not react chemically with other substances during the fire extinguishing process, and will not produce toxic and harmful gases. It is friendly to the environment and personnel safety.

[0040] 3. Reduce the probability of re-ignition: Low-temperature nitrogen can not only quickly reduce the temperature of fire zone 4, but also replace the oxygen in fire zone 4 and reduce the oxygen concentration, thereby greatly reducing the possibility of re-ignition.

[0041] 4. Economical: Nitrogen is one of the main components in the atmosphere, and its acquisition cost is low. The investment cost of the nitrogen production system and nitrogen injection pipeline is relatively low, and the operating cost is also low, which has good economical efficiency.

[0042] Although the utility model is described in detail by referring to the accompanying drawings and in combination with the preferred embodiments, the utility model is not limited thereto. Without departing from the spirit and essence of the utility model, a person of ordinary skill in the art may make various equivalent modifications or substitutions to the embodiments of the utility model, and these modifications or substitutions shall be within the scope of the utility model / any person of ordinary skill in the art who is familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the utility model, and they shall be within the scope of protection of the utility model. Therefore, the scope of protection of the utility model shall be based on the scope of protection of the claims.

Claims

1. A circulating nitrogen injection cooling system for rapidly reducing the temperature of a fire zone in a closed goaf, comprising a working face (3) opened at the front end of the goaf (5), the working face (3) being connected to an air inlet tunnel (1) and a return air tunnel (2), characterized in that: A measure tunnel (6) is opened on one side of the goaf (5); a nitrogen loop is arranged between the measure tunnel (6) and the fire zone (4) of the goaf (5); a nitrogen generator (9) is connected to one end of the nitrogen loop, and an air cooler (8) is connected to the outlet of the nitrogen generator (9); a vacuum pump (10) is connected to the other end of the nitrogen loop; the nitrogen generator (9), the air cooler (8) and the vacuum pump (10) are all arranged in the measure tunnel (6).

2. The circulating nitrogen injection cooling system for rapidly reducing the temperature of the fire zone in the closed goaf according to claim 1 is characterized in that: The nitrogen loop comprises a nitrogen inlet pipe (7) and a nitrogen return pipe (11); one end of the nitrogen inlet pipe (7) is connected to the outlet of the air cooler (8), and the other end is open and arranged in the fire zone (4) of the goaf (5); one end of the nitrogen return pipe (11) is connected to the inlet of the vacuum pump (10), and the other end is open and arranged in the fire zone (4) of the goaf (5).

3. The circulating nitrogen injection cooling system for rapidly reducing the temperature of the fire zone in the closed goaf according to claim 2 is characterized in that: The distance between the open end of the nitrogen inlet pipe (7) and the open end of the nitrogen return pipe (11) is ≤ 5 m.

4. The circulating nitrogen injection cooling system for rapidly reducing the temperature of the fire zone in the closed goaf according to claim 3 is characterized in that: The distance between the end of the nitrogen inlet pipe (7) away from the air cooler (8) and the end of the nitrogen return pipe (11) away from the vacuum pump (10) is equal to 5 m.

5. The circulating nitrogen injection cooling system for rapidly reducing the temperature of the fire zone in the closed goaf according to claim 3 is characterized in that: The extending direction of the measure tunnel (6) is perpendicular to the working surface (3) and parallel to the air inlet tunnel (1) or the air return tunnel (2).

6. The circulating nitrogen injection cooling system for rapidly reducing the temperature of the fire zone in the closed goaf according to claim 5 is characterized in that: The depth of the measure tunnel (6) is set to be smaller than the depth of the working surface (3).

7. The circulating nitrogen injection cooling system for rapidly reducing the temperature of the fire zone in the closed goaf according to claim 2 is characterized in that: Flow meters are provided on both the nitrogen inlet pipe (7) and the nitrogen return pipe (11).

8. The circulating nitrogen injection cooling system for rapidly reducing the temperature of the fire zone in the closed goaf according to claim 7 is characterized in that: A gas concentration sensor and a temperature sensor are provided at the gas outlet end of the vacuum pump (10).

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