Experimental Study On Micro-pore Of Coal By Low Temperature Nitrogen Adsorption Method

The pore structure of coal is used to characterize the occurrence of gas,it is also important to solve the problem of high gassy mine.The paper apply Physical chemistry adsorption instrument of type ASAP 2020 analyze the pore structure of different metamorphic grade coal,with low temperature nitrogen adsorption method,and adsorption models like Langmuir,BET,Freundlich,DFT etc.are used to analyze microscopic pore structure.According to the adsorption constants regularity,it shows that with the metamorphic grade increasing,the adsorption capacity of coal increase.The change regularity of coal's surface area and total pore volume is not obvious in metamorphic grade.it shows that with the increase of metamorphism degree,pore diameter of coal change to micropore via transitional pore,the volume of transitional pore is larger than micropore,and the micropore volume percentage show an increase tendency with metamorphic degree increasing.with the increase of metamorphism degree,adsorption of the coal surface becomes complex and adsorption capacity becomes larger.Correlation Coefficient of various adsorption model comparison with the experimental data,DFT method are more reliable the relative pressure between 0 and 0.995.Study on microscopic pore structure to analysis adsorption capacity,adsorption amount of coal,and obtain the relationship between pore structure and gas occurrence,to provide the theoretical basis of high gassy's coal mine drainage.