Basic Research On Microscopic Mechanism Of Coal And Gas Outburst

Mechanism of coal and gas outburst and its occurrence condition have been studied macroscopically for a long time. Due to the complexity, causes, processes and certain details of coal and gas outburst are not very definite. Combined National Natural Science Foundation Project"Study on Occurrence Law of Abnormal Discharge of High Gas and Outburst Gas"(No. 50574047), according to induced source, excess gas source in the process of outburst, and based on hypothesis of coal and gas outburst comprehensive effect, the basic research on microscopic mechanism of coal and gas outburst is launched using the method of integration of theory with practice. Main research contents and achievements are as follows:Applying quantum chemistry theory of density functional theory and quantum chemistry Gaussian03, adsorption microscopic mechanism of coal and gas is studied with calculation method of quantum chemistry. On the level of B3LYP/6-311G adsorption model of molecular fragments on coal surface and methane molecule is built; molecular configuration parameters are calculated; physical adsorption of molecular fragments of coal and methane molecule is proved, the adsorption energy is 1.34KJ/mol.Based on the previous research, desorption microscopic mechanism of coal and gas is studied with quantum mechanics theory and electromagnetic wave technique. It is shown that mine earthquake, mining and explosion activities cause coal and rock mass broke and deformed, which produced electromagnetic wave that is absorbed by associated molecule system of coal and CH4 in form of energy within certain frequency scope, and therefore this system is changed to excited state from ground state. Critical frequency v 0 of desorption of coal and gas have been put forward constructively. Through the calculation of quantum mechanics, the value of frequency v 0 is obtained within extreme infrared frequency scope. Only when the wave frequency v exceeds critical frequency, desorption of coal and gas will happen. Using Fourier transform infrared spectrometer TENSOR27, superfine pulverized coal in outburst coal and lump coal molecular structure is studied with infrared spectrum experiment. The infrared spectrum of superfine pulverized coal in outburst coal and lump coal is analyzed. Put forward the basic reasons that superfine pulverized coal in the number of groups is far less than the lump coal, lie in the organic macro-molecule side chain groups pulled off and the result of the release of low molecular compounds, thus result in producing excess gas. This experiment firstly reveals the source of the release of excess gas in coal and gas outburst process from the microscopic view.To sum up, the coal and gas adsorption, desorption and other aspects of the coal and gas outburst microscopic mechanism are put forward. In coal mine production, due to mine earthquake, mining and explosion activities, the stress change of surrounding rock on extraction face causes coal and rock mass broke, which produces electromagnetic wave with broad frequency scope. Associated molecule system formed from adsorption of coal and CH4 absorbs electromagnetic wave exceeding desorption critical frequency in form of quantum, which result in this system turns to excited state from ground state, and the gas turns to free state from adsorption state through desorption, forms a large number of free gas. If have high ground stress and condition of forming coal, therefore the dynamic phenomenon of coal and gas outburst is very easy to happen in weak plane.