Design of intelligent pressure balance fire prevention and extinguishing system for shallow-buried coal seams

In the Jin–Shan–Meng region, the risk of residual coal spontaneous combustion and harmful gas emissions in shallow-buried coal seam goafs is prominent. In view of the limitations of existing technologies such as positive pressure ventilation, nitrogen injection, and grouting in terms of dynamic oxygen control and inerting effect, as well as the problem that traditional pressure balance ventilation relies on static thresholds and single-parameter feedback, an intelligent pressure balance fire prevention and extinguishing system for shallow-buried coal seams was designed. An intelligent perception technology for ventilation parameters in pressure balance working faces was proposed, and a sensor network was deployed in key areas such as goafs and sealed zones to synchronously collect and integrate differential static pressure, air leakage volume, gas (O₂, CO, CH₄) concentrations, temperature, and other data for analysis. A multi-dimensional dynamic index system and a pressure balance effect evaluation model based on the Equalization Performance Index (EPI) were established, and graded early warning was implemented according to the evaluation results. A combined regulation system of louvered air windows and variable-frequency local ventilators was constructed, forming a collaborative mechanism of precise micro-adjustment by air windows and large-scale compensation by ventilators. Engineering practice showed that after the system was put into operation, the pressure difference at the working face decreased from the original 120.9 Pa to 35.8 Pa, the air leakage volume in the goaf decreased from 346.4 m³/min to 98.5 m³/min, the O₂ volume fraction at the upper corner increased from 16.0% to 18.5%, and the CO volume fraction decreased from 93.8×10⁻⁶ to 14.8×10⁻⁶, effectively suppressing coal spontaneous combustion and harmful gas emissions.