Mine low-temperature nitrogen-water mist mixed fire extinguishing system

Abstract

The utility model discloses a kind of mine low-temperature nitrogen-water mist mixed fire prevention and extinguishing system, including semiconductor heat exchange sheet, the liquid cooling tank is set on semiconductor heat exchange sheet side, the other side is set with stainless steel radiating fin, the liquid cooling tank both sides are set with heat dissipation air duct, and heat dissipation fan is set in heat dissipation air duct bottom;The upper air inlet end of liquid cooling tank is communicated with nitrogen generator by air inlet pipeline and valve a;The lower air outlet end of liquid cooling tank is connected by pipeline with the liquid inlet pipeline and valve c of water source and the air outlet pipeline and valve b;Unidirectional valve d is set on pipeline.The utility model has the characteristics of low-temperature nitrogen and water mist physical-chemical synergistic cooling, normal-pressure safe operation.

Description

Technical Field

[0001] This utility model relates to the field of coal mine fire prevention and extinguishing technology, and in particular to a mine-use low-temperature nitrogen-water mist mixed fire prevention and extinguishing system. Background Technology

[0002] In recent years, with the advancement of deep and medium-thick coal seam mining, while coal mining technology has improved production efficiency, it has also given rise to new problems such as large-scale goaf collapses, coal residue accumulation, and disordered ventilation systems. These factors have significantly increased the risk of spontaneous combustion of coal, leading to frequent fire accidents, and have now become a key bottleneck restricting the sustainable development of the coal industry, posing a major safety hazard.

[0003] Current methods for fire prevention and extinguishing in mine goaf areas primarily revolve around nitrogen injection as the main method, supplemented by other fire prevention and extinguishing techniques. The core principle of nitrogen injection is to extinguish the fire by reducing the oxygen concentration in the combustion environment. Currently, nitrogen injection methods are divided into two types: nitrogen generation and direct liquid nitrogen injection. Nitrogen generation involves filtering nitrogen from the air through physical separation and injecting it into the goaf. The nitrogen outlet temperature in the goaf is approximately 25℃±5℃. Direct liquid nitrogen injection involves purchasing liquid nitrogen tank trucks from liquid nitrogen manufacturers, filling them with liquid nitrogen, connecting them through pipelines, and then transporting the vaporized liquid nitrogen over long distances into the goaf. The liquid nitrogen temperature is approximately -196℃, and the nitrogen outlet temperature in the goaf is approximately 14±5℃. The main drawbacks are as follows: (1) Traditional nitrogen injection mechanisms rely solely on inerting to reduce oxygen concentration. However, when the coal body in the goaf undergoes oxidation and heat release (usually >60℃), the heat exchange efficiency of room temperature nitrogen (25℃±5℃) is low, which cannot effectively suppress free radical chain reactions, leading to an increased risk of fire point reignition. (2) Although direct injection of liquid nitrogen can achieve injection into the goaf at a lower temperature, the temperature loss is too large and the transportation and storage costs are high. (3) Direct injection of liquid nitrogen into the empty space of the pressure vessel poses a risk of accidents such as low temperature and physical explosion. Summary of the Invention

[0004] In order to overcome the above technical problems, the purpose of this utility model is to provide a mine-use low-temperature nitrogen-water mist mixed fire prevention and extinguishing system, which has the characteristics of physical-chemical synergistic cooling of low-temperature nitrogen and water mist and safe operation at normal pressure.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is as follows: A low-temperature nitrogen-water mist mixed fire extinguishing system for mining includes a semiconductor heat exchanger 11, a liquid cooling box 12 is provided on one side of the semiconductor heat exchanger 11, and a stainless steel heat dissipation fin 10 is provided on the other side. Heat dissipation air ducts 4 are provided on both sides of the liquid cooling box 12, and a heat dissipation fan 13 is provided at the bottom of the heat dissipation air ducts 4. The upper air inlet of the liquid cooling box 12 is connected to the nitrogen generator 6 through an air inlet pipe and valve a5; The lower air outlet of the liquid cooling box 12 is connected to the water source's inlet pipe and valve c8, as well as the air outlet pipe and valve b7; a one-way valve d9 is installed on the pipe.

[0006] The gas outlet pipeline and valve b7 are connected to the nitrogen injection pipeline 16 via the high-pressure hose 15.

[0007] The semiconductor heat exchanger 11 is connected to the PLC controller 1 via the connecting wire 3.

[0008] The heat dissipation duct 4 is a rectangular air duct formed by stainless steel surrounding stainless steel heat dissipation fins 10. It generally wraps around the liquid cooling box 12 horizontally to form a nest with it. Under the blowing of the heat dissipation fan 13, hot air is discharged from the air outlets 17 on both sides.

[0009] The stainless steel heat dissipation fins 10 are several stainless steel sheet-like structures arranged in parallel to form a section of the heat dissipation side that is in close contact with the semiconductor heat exchanger 11. The heat generated by the semiconductor heat exchanger 11 is conducted through heat conduction. Each semiconductor heat exchanger 11 is provided with heat dissipation holes to increase the heat exchange gap and facilitate the heat dissipation fan 13 to carry away the heat through ventilation.

[0010] The semiconductor heat exchanger 11 uses an insulating thermally conductive sheet (ceramic) as a carrier, and the surface is fixed with a semiconductor thermoelectric unit (P / N type material) by conductive adhesive or solder to form a heat conduction path. After being powered on, the cooling side absorbs heat and cools down in the liquid cooling medium, while the heat dissipation side is in contact with the stainless steel heat dissipation fins 10 to heat up and release heat.

[0011] The beneficial effects of this utility model.

[0012] The liquid-cooled box 12 in the mine-use low-temperature nitrogen-water mist mixed fire extinguishing system 14 cools the nitrogen to -30±5℃, which is more than 55℃ higher than the temperature difference of the traditional nitrogen injection machine (25℃). Low-temperature nitrogen can effectively inhibit the free radical chain reaction of coal. Experimental data shows that the cooling rate of oxidized coal at 60℃ is increased by 3.2 times, and the probability of fire re-ignition is reduced by 87%.

[0013] Low-temperature nitrogen gas is mixed with water supplied through the outlet pipe and valve b at the inlet pipe and valve c8, forming a water mist that is sprayed onto the gas. This mixture utilizes the heat absorption during water vaporization (theoretically 2257 kJ / kg) to create a dual cooling effect. Field tests show that, at the same nitrogen flow rate, the mixed medium increases the cooling efficiency of the goaf by 40%, and the water mist particles can adsorb coal dust, reducing the risk of gas explosion.

[0014] Eliminates the extreme low temperature (-196℃) and explosion risk of direct liquid nitrogen injection; the mine-use low-temperature nitrogen-water mist mixed fire extinguishing system 14 cools the nitrogen from room temperature to -30±5℃ without any pressurization steps. After liquid cooling heat exchange, the nitrogen is in a normal pressure low-temperature state. The entire operation is controlled by a PLC controller 1 to avoid direct human contact with low-temperature nitrogen. Compared with direct liquid nitrogen injection, it avoids the risk of pressure vessel explosion and reduces the risk of personnel directly contacting low-temperature nitrogen.

[0015] A mine-use cryogenic nitrogen-water mist mixed fire extinguishing system (14) is adopted, which is connected to a nitrogen generator (6) to inject cryogenic nitrogen, replacing the direct injection of cryogenic nitrogen from liquid nitrogen. This eliminates the need for liquid nitrogen transportation and storage, improving work efficiency. The device is installed underground and only needs to be connected to the mine's existing nitrogen generator and injection pipeline to begin operation. Compared to direct liquid nitrogen injection, it eliminates the need for liquid nitrogen to be transported from the manufacturer to the site by tanker truck and then returned to the manufacturer for refilling, thus improving work efficiency.

[0016] For the high-temperature environment of deep goaf areas, the -40℃ liquid cooling medium can operate continuously for more than 8 hours. The mine-use low-temperature nitrogen-water mist mixed fire extinguishing system 14 has a simple structure. During normal operation, there is no high-temperature or high-pressure state, and there are no complex connections. Ethylene glycol is used as the liquid cooling medium in the liquid cooling box 12. After ethylene glycol is mixed with water, its hydroxyl groups form hydrogen bonds with water molecules, destroying the crystal structure of water molecules and significantly lowering the freezing point of the solution. The freezing point of a 68% ethylene glycol aqueous solution can reach -68℃, meeting the low-temperature cooling requirements. Combined with the nitrogen generator 6, it forms a continuous inertization protection zone, effectively solving the "cooling-reignition" cycle problem of traditional technologies. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a low-temperature nitrogen-water mist mixed fire prevention and extinguishing system for mining.

[0018] Figure 2 This is a schematic diagram for system layout.

[0019] Figure 3 This is a schematic diagram of the heat dissipation airflow.

[0020] Figure 4 This is a schematic diagram of stainless steel heat sink fins.

[0021] Figure 5 This is a schematic diagram of a semiconductor heat exchanger.

[0022] 1. PLC controller; 2. Power supply; 3. Connecting wires; 4. Cooling duct; 5. Inlet pipe and valve a; 6. Nitrogen generator; 7. Outlet pipe and valve b; 8. Liquid inlet pipe and valve c; 9. One-way valve d; 10. Stainless steel heat sink fins; 11. Semiconductor heat exchanger; 12. Liquid cooling box; 13. Cooling fan; 14. Mining low-temperature nitrogen-water mist mixed fire extinguishing system; 15. High-pressure hose; 16. Nitrogen injection pipe; 17. Air outlet. Detailed Implementation

[0023] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0024] like Figures 1-3 As shown, a low-temperature nitrogen-water mist mixed fire extinguishing system for mining includes a semiconductor heat exchanger 11. A liquid cooling box 12 is provided on one side of the semiconductor heat exchanger 11, and a stainless steel heat dissipation fin 10 is provided on the other side. Heat dissipation air ducts 4 are provided on both sides of the liquid cooling box 12, and a heat dissipation fan 13 is provided at the bottom of the heat dissipation air ducts 4. The upper air inlet of the liquid cooling box 12 is connected to the nitrogen generator 6 through an air inlet pipe and valve a5; The lower air outlet of the liquid cooling box 12 is connected to the water source's inlet pipe and valve c8, as well as the air outlet pipe and valve b7; a one-way valve d9 is installed on the pipe.

[0025] The gas outlet pipeline and valve b7 are connected to the nitrogen injection pipeline 16 via the high-pressure hose 15.

[0026] The semiconductor heat exchanger 11 is connected to the PLC controller 1 via the connecting wire 3.

[0027] The heat dissipation duct 4 is a rectangular air duct formed by stainless steel surrounding stainless steel heat dissipation fins 10. It generally wraps around the liquid cooling box 12 horizontally to form a nest with it. Under the blowing of the heat dissipation fan 13, hot air is discharged from the air outlets 17 on both sides.

[0028] like Figure 4 As shown, the stainless steel heat dissipation fins 10 are several parallel sheet-like structures made of stainless steel, forming a section that is in close contact with the heat dissipation side of the semiconductor heat exchanger 11. Heat generated by the semiconductor heat exchanger 11 is conducted through heat transfer. Each semiconductor heat exchanger 11 has heat dissipation holes to increase the heat exchange gap and facilitate heat dissipation. Figure 5 As shown, the hot air blower 13 removes heat through ventilation.

[0029] The semiconductor heat exchanger 11 uses an insulating thermally conductive sheet (ceramic) as a carrier, and the surface is fixed with a semiconductor thermoelectric unit (P / N type material) by conductive adhesive or solder to form a heat conduction path. After being powered on, the cooling side absorbs heat and cools down in the liquid cooling medium, while the heat dissipation side is in contact with the stainless steel heat dissipation fins 10 to heat up and release heat.

[0030] When the power supply 2 is turned on, the semiconductor heat exchanger 11 starts to work, which can lower the working temperature of the ethylene glycol liquid cooling medium to -40°C. At this time, the semiconductor heat exchanger 11 cools on the side of the liquid cooling medium and generates heat on the side of the stainless steel heat sink 10. The semiconductor heat exchanger 11 transfers the heat to the stainless steel heat sink 10 through heat conduction. In order to prevent the heat from accumulating and reducing the cooling effect, the heat generated is blown into the heat dissipation duct 4 by the heat dissipation fan 13 and discharged from the top of the equipment.

[0031] Nitrogen generated by nitrogen generator 6 enters the liquid cooling tank 12 through the inlet pipe and valve a5, reducing the ambient temperature nitrogen gas (25℃±5℃) to a cryogenic temperature of -30±5℃. This cryogenic nitrogen is then discharged through one-way valve d9. The cryogenic nitrogen mixes with water entering through the liquid inlet pipe and valve c8 connected to the water source and is discharged through the outlet pipe and valve b7. The outlet pipe and valve b7 are connected to the nitrogen injection pipe 16 via a high-pressure hose 15, thereby injecting the cryogenic water-gas mixture into the abnormal area of ​​the goaf for fire prevention and extinguishing.

[0032] How to use: 1. When transporting the mine-use low-temperature nitrogen-water mist mixed fire prevention and extinguishing system (hereinafter referred to as the system) to the release location using a mine flatbed truck, the closer the end of the system is to the outlet, the better the fire prevention and extinguishing effect; 2. Connect the nitrogen generator 6 to the system through the air inlet pipe and valve a5, connect the water source to the system through the liquid inlet pipe and valve c8, and connect the air outlet pipe and valve b7 to the nitrogen injection pipe 16 through the high-pressure hose 15. Keep all valves closed. 3. Turn on the power 2 to start the system for pre-cooling, which takes 10 minutes; 4. Open all valves, start nitrogen generator 6, and carry out normal fire prevention and extinguishing work; 5. After the work is completed, perform the following tasks in sequence: turn off the power 2 to stop the system from refrigerating, close the liquid inlet pipe and valve c8 to drain the water in the pipe, turn off the nitrogen generator 6, and close all valves. The entire work is now complete.

Claims

1. A low-temperature nitrogen-water mist mixed fire suppression system for mining, characterized in that, It includes a semiconductor heat exchanger (11), a liquid cooling box (12) is provided on one side of the semiconductor heat exchanger (11), and a stainless steel heat dissipation fin (10) is provided on the other side. Heat dissipation air ducts (4) are provided on both sides of the liquid cooling box (12), and a heat dissipation fan (13) is provided at the bottom of the heat dissipation air ducts (4). The upper air inlet of the liquid cooling box (12) is connected to the nitrogen generator (6) through an air inlet pipe and valve a (5); The lower air outlet of the liquid cooling box (12) is connected to the water source inlet pipe and valve c (8) and the air outlet pipe and valve b (7) through a pipe; a one-way valve d (9) is installed on the pipe.

2. The mine-use low-temperature nitrogen-water mist mixed fire suppression system according to claim 1, characterized in that, The gas outlet pipeline and valve b (7) are connected to the nitrogen injection pipeline (16) via a high-pressure hose (15).

3. The mine-use low-temperature nitrogen-water mist mixed fire suppression system according to claim 1, characterized in that, The semiconductor heat exchanger (11) is connected to the PLC controller (1) via connecting wire (3).

4. A mine-use low-temperature nitrogen-water mist mixed fire suppression system according to claim 1, characterized in that, The heat dissipation duct (4) is a rectangular air duct formed by stainless steel surrounding stainless steel heat dissipation fins (10). It is generally horizontally wrapped around the liquid cooling box (12) and nested with it. Under the blowing of the heat dissipation fan (13), hot air is discharged from the air outlets (17) on both sides.

5. A mine-use low-temperature nitrogen-water mist mixed fire suppression system according to claim 1, characterized in that, The stainless steel heat sink fins (10) are a number of stainless steel sheet-like structures arranged in parallel to form a heat dissipation side that is in close contact with the semiconductor heat exchange plate (11). Each semiconductor heat exchange plate (11) is provided with heat dissipation holes.

6. A mine-use low-temperature nitrogen-water mist mixed fire suppression system according to claim 1, characterized in that, The semiconductor heat exchanger (11) uses an insulating heat-conducting sheet as a carrier, and the surface is fixed with conductive adhesive or solder to form a heat conduction path.

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