Study On The Conductive Ions On Electric Pulse Fracturing Effect Of Coal Pore Structure

Electric pulse fracturing coal seam permeability enhancement is a new technology of gas analysis that is based on high-pressure shock wave technology.However,the technology of electric pulse fracturing coal seam permeability enhancement has some problems,such as high risk,fast energy loss and so on.Therefore,two kinds of anthracite and one kind of bituminous coal are selected and treated with NaCl,CaCl₂ and AlCl₃ of five concentration gradients.Using the experimental research platform of high voltage electric pulse fracturing and permeation enhancement,in this paper,the adsorption behavior and law of anthracite and bituminous coal surface before and after treatment with different concentration and different kinds of ionic solution are studied,the change law of field strength and voltage before and after treatment,the macro and micro fracture characteristics of coal sample before and after treatment,and the evolution law of pore and fracture structure are also studied.The results show that the higher the cationic valence of the solution,the more ions are adsorbed on the treated coal surface.With the increase of immersion time,the amount of ions are adsorbed on the coal particle surface finally that is reached the saturation state.After the treatment of the conductive ion solution,a certain number of conductive ions are attached to the coal surface,so that the conductive properties of the coal are obtained and the voltage condition of high voltage pulse breakdown coal body is improved.In the process of high voltage pulse breakdown,the plasma channel in coal body develops and derives more fully,which greatly reduces the breakdown voltage of coal sample.At the same time,the breakdown degree of coal body by electric pulse is more obvious,and the fracture network formed on the surface of coal body is more abundant.After treatment,the total pore volume,total specific surface area,porosity and average pore diameter of coal body breakdown have a certain extent.With the increase of pore size coverage,the percentage of large and medium pore increases,the percentage of small and micro-pore decreases,and the pore structure of coal body is more fully reformed.It shows that after the treatment of conductive ion solution,the original discrete pore size connectivity of coal body after high voltage electric pulse breakdown is obviously enhanced,which is more conducive to the development of gas permeability of coal body.