Study on influence of different factors on the peak concentration distribution of desorption gas under the action of gas sustained-release agent

In order to prevent coal mine gas accidents and realize efficient and accurate gas extraction, spraying gas sustained-release agent in local high concentration gas area has become one of the important means to prevent and control gas overlimit. The self-developed multi-factor influencing coal gas desorption and spraying experiment platform, built based on the similarity ratio model of coal mine driving working face, was used to study the law of different factors affecting the peak concentration distribution of desorbed gas under spraying gas sustained-release agent. The effects of APG solution mass fraction, atomizing pressure, coal sample particle size, equilibrium pressure, ambient temperature, wind speed and other factors on the peak concentration distribution of desorbed gas were analyzed. The Pearson correlation coefficient method was used to obtain the correlation between the factors and the peak gas concentration in different areas after spraying gas sustained-release agent. The results shown that, the peak gas concentration declined rapidly with increasing mass fraction for APG solution mass fraction less than 0.10%, and the decline rate decreased when it exceeded 0.10%. Under the effect of sustained-release agent, the peak gas concentration shown negative linear and negative exponential relationship with atomization pressure and coal sample particle size, respectively. The peak gas concentration decreased with the increase of atomization pressure and coal sample particle size, and the maximum gas reduction rate was observed when the coal sample particle size was 5-10 mm. The peak gas concentration shown linear and exponential relationship with equilibrium pressure and ambient temperature, respectively. The peak gas concentration increased with the increase of equilibrium pressure and ambient temperature, and the growth rate of peak gas concentration was the highest when the ambient temperature was 35 °C. The peak gas concentration at the center and corners of the working face model decreased with increasing wind speed, and the reduction rate of peak gas concentration decreased when the wind speed exceeded 12.7×10⁻³ m³/s. The peak gas concentration was reduced by 4.3%-8.0% with multiple factors compared to a single factor. Using the correlation coefficient method, the maximum factors affecting the peak gas concentration at the upper and lower corners of the inlet, upper and lower corners of the outlet, and the center of the model were obtained as atomization pressure, atomization pressure, equilibrium pressure, ambient temperature and equilibrium pressure, respectively.