Coal spontaneous combustion in the gob poses a significant threat to coal mining operations. Designing optimal process parameters for nitrogen injection to prevent and control fires efficiently is crucial. To achieve this, a multi-field coupling equation was established, considering the adsorption of coal to gas. The model's accuracy was verified on-site, and the effects of nitrogen injection at different locations and flow rates were simulated. The optimal injection parameters were determined by analyzing temperature and inerting time. The results showed that the coal spontaneous combustion hazardous zone in the gob tested on-site was consistent with the simulation from the perspective of physisorption. Nitrogen injection had three stages: gas expansion, rapid oxygen dilution, and complete inerting. The nitrogen injection effect presented a nonlinear change in injection location and flow rate. The optimal nitrogen injection location for the Tingnan Coal Mine in Shaanxi was determined to be 90 m behind the working face on the inlet side, with an optimal flow rate of 800 m3/min. This study focused on gas adsorption and offered valuable insights for creating high-efficiency fire-fighting techniques that involve inserting in the gob.
Keywords: Coal spontaneous combustion; Fire-fighting; Gas adsorption; Gob fire; Inerting zone; Optimization of nitrogen injection parameters.
© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.