Normalizing Fire Prevention Technology and a Ground Fixed Station for Underground Mine Fires Using Liquid Nitrogen: A Case Study

Coal mine fires continuously attract the attention of researchers recently. Firefighting is the most important activities for protecting the mining safety and coal resources at the same time. Among them, liquid nitrogen is usually employed as emergency treatment for sudden fire accidents. However, it as a normalized fire prevention technology is still in the blank. Subsequently, a new system called ground fixed liquid nitrogen station has been developed for normalizing fire prevention. It took 5months to build such total flooding fire extinguishing systems in JF colliery, with a maximum flow rate: 5000Nm(3)/h, pressure: 1.0 +/- 0.05MPa, high purity: 99.99%, and outlet temperature of CGN is 10 degrees C lower than the atmospheric temperature. Field observations showed that it only took 3days for the concentration of CO to decrease by 95.36%. The main fire extinguishing mechanism of the system is the nitrogen inertization, and the cooling effect is supplemented. By using the presented technique, there was no waste left behind. Thus, it is concluded that the newly developed firefighting system can be put into practice, especially its broad application prospects in large capacity collieries.