Study On The Influence Of Gas Release Mechanism Of Gas-containing Coal Under Liquid Immersion

At present,hydraulic outburst prevention technology has been widely used in the field of coal mine production.It is one of the effective measures to prevent coal and gas outburst,rock burst and other disasters.Nowadays,in the process of hydraulic outburst prevention,the understanding that water has a great impact on the desorption of coal gas has been relatively in-depth.However,in some cases,not only water will invade the coal,but also liquid water will submerge the coal,such as the hydraulic drainage of coalbed methane and the flooding of coal after the rebound of groundwater in abandoned mines.In order to understand the emission characteristics and influencing factors of gas bearing coal under clear water flooding environment,this paper first investigated the research status at home and abroad,built an experimental device for testing the gas desorption law of gas bearing coal under liquid immersion in the laboratory,carried out the water immersion experiment of raw coal under different surfactant solutions and the desorption experiment of gas bearing coal under water flooding,and tested the surface tension and contact angle of the solution,The pore characteristics of experimental coal samples were tested by mercury injection method.The following experimental results were obtained through experimental test and theoretical analysis.The desorption experiment of gas bearing coal under water flooding takes Xinjing coal sample as the research object.The gas desorption experiment is carried out under different inflation and different liquid immersion time.Through the analysis of experimental data,the change curves of cumulative desorption amount and desorption speed are drawn.The following results are obtained through experimental analysis: the length of liquid leaching will affect the cumulative desorption of coal,and the cumulative desorption will decrease under the same inflation;The initial desorption rate of liquid leached coal is lower than that of dry coal when other conditions remain unchanged;Under different inflation pressure,the cumulative desorption capacity of gas bearing coal under liquid leaching increases with the increase of inflation pressure.The raw coal soaking experiment takes the raw coal of Jiulishan mine,Xinjing mine and Tunlan Mine as the research object.Through the processing of the soaking experimental data of different surface tension solutions,the cumulative desorption capacity and desorption speed are fitted,and the relationship between the cumulative water inflow and water inflow speed of coal samples and time is obtained.The experimental results show that surfactants have different effects on the water inflow law of different coal samples.From the perspective of total water inflow,Jiulishan coal >Xinjing coal > Tunlan coal.From the perspective of water inflow speed,Xinjing coal >Tunlan Coal > Jiulishan coal.In the inorganic salt solution,the cumulative water inflow of anthracite is smaller than that of coking coal,which is positively correlated with the total pore volume of coal.