| Coal and gas outburst is a complicated dynamic phenomenon of coal mining, which is a serious threat to the coal mine production safety. At present, the mechanism of coal and gas outburst has been studied by domestic and foreign scholars for many years. The combination hypothesis has been universally recognized. It believes that coal and gas outburst is controlled by earth stress, gas pressure and physical and mechanical properties of coal.Based on this hypothesis, the experimental platform of coal desorbed gas under the effect of different excitation source and the experiment system of coal gas outburst simulation were designed and made. The thesis studies the following contents:the influence of different excitation sources on coal desorbed gas and the influence factors of coal and gas outburst. The result provides the reliable data for preventing the coal and gas outburst. Anthracite coal was collected from Shanxi and its adsorption gas had been pumped clearly.The influence of electromagnetic and temperature on coal gas desorption were researched in first part and the impact of coal particle size and moisture content on coal gas desorption under the effect of electromagnetic radiation were also studied. Infrared (IR) spectroscopy and optical fiber sensor were used to on-line detect and the qualitative and quantitative analysis of the desorbed gas. The results are as follows.(1) Gas which contained carbon dioxide, carbon monoxide and methane can be desorbed by anthracite under the effect of electromagnetic and temperature. After gas desorbed, coal size became smaller and its distribution became more uniform. Gas content which is desorbed by coal under the effect of electromagnetic is much higher than the temperature effect.(2) Coal particle size has some effect on gas content. With decreasing of coal particle, gas content remains stable at first and then increases quickly, finally drops.(3) Coal moisture content has great influence to gas content. With the increase of water content in coal, gas content is reduced.The second part mainly studied the influence of gas species and its state on the intensity of coal and gas outburst and whether nitrogen can inhibit coal and gas outburst. The content of pulverized coal was used to reflect the intensity of gas outburst. The conclusions are as follows:Releasing of adsorbed gas can make coal crushing. That can be used to evaluate the influence of gas species and its state on the intensity of coal and gas outburst.(1) When coal and gas outburst occurred, coal sample would be shattered. Under the same experiment conditions, the higher the methane content in gas was, the more pulverized coal would be produced.(2) Gas state has a certain impact on gas outburst. Under a certain temperature and in a certain adsorption time, the content of pulverized coal increases rapidly, when the state of methane changed from a sub-critical to a supercritical.(3) The granularity of coal has some effect on gas outburst. At the same experiment conditions, the smaller the particle size of coal samples, the higher the content of pulverized coal and the greater the intensity of coal and gas outburst.(4) Under certain adsorption temperature and adsorption time, when injected nitrogen into coal which had been adsorbed methane, the content of pulverized coal became less. It shows that nitrogen injection has affected coal methane adsorption and reduces the intensity of gas outburst. |
PDF Full Text Request