A liquid nitrogen fire extinguishing system and method

Abstract

The invention discloses a liquid nitrogen fireproof fire extinguishing system, comprising a liquid nitrogen tank car; the liquid nitrogen tank car is connected with a pump, a vertical shaft and a liquid nitrogen conveying main pipe in sequence; the liquid nitrogen conveying main pipe is connected with a liquid nitrogen direct injection pipe for injecting liquid nitrogen into a goaf and a liquid nitrogen gasifying device for gasifying the liquid nitrogen into nitrogen and then injecting the nitrogen into the goaf; the goaf is integrally provided with an exhaust pipe connected with an air return pipeline; the exhaust pipe is provided with a first control valve; the goaf is internally provided with a sensor for monitoring pressure. The invention also discloses a liquid nitrogen fireproof fire extinguishing method. The liquid nitrogen fireproof fire extinguishing system and the method have the beneficial effects that the exhaust pipe is arranged in the goaf, when the pressure in the goaf is larger than a preset value, air in the goaf can be exhausted, so the pressure of the goaf is reduced, the nitrogen filling speed is improved, and inert gas and harmful gas in the goaf are prevented from escaping from cracks in upper edges corners of the goaf into a working area under action of high pressure.

Description

technical field [0001] The invention relates to coal mine underground fire prevention and cooling technology, in particular to a liquid nitrogen fire prevention and fire extinguishing system and method. Background technique [0002] According to statistics, mines with the risk of spontaneous combustion in my country's key state-owned coal mines account for about 51.3%, and fires caused by spontaneous combustion account for more than 90% of the total number of fires. problem. [0003] Conventional fire prevention and extinguishing techniques commonly used at this stage mainly include grouting, inhibitor injection, nitrogen injection, etc. The use of nitrogen for fire extinguishing can not only quickly extinguish a large fire area of ​​tens of thousands of meters, but also suppress the explosion of combustible gas in the fire area, and improve the safety during the fire extinguishing process. Especially the use of liquid nitrogen to extinguish the fire, liquid nitrogen will a...

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Problems solved by technology

Especially the use of liquid nitrogen to extinguish fires, liquid nitrogen will absorb a large amount of heat during the gasification process, which can reduce the ambient temperature of the goaf, prevent the floating coal in the gob from oxidizing and spontaneously igniting, or quickly extinguish the fire caused by the oxidizing and spontaneous combustion of floating coal However, after injecting liquid nitrogen and nitrogen gas, the air pressure in the goaf becomes larger. Due to the low density of nitrogen, it becomes difficult to continue injecting nitrogen into the gob, which leads to a decrease in the nitrogen injection rate and cannot be quickly injected. Extinguish the fire; and there will be cracks in the upper corner of the goaf because of roof collapse and other reasons. If the pressure of the gob is too high, the harmful gas (such as gas) and inert gas in the gob will be released under the action of high pressure. Escape to the work area through cracks, causing hazards to the work area

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