Study On The Correlation Between The Microstructure Of Different Coal Rank And Gas Adsorption Desorption

The pore structure of coal is very complex,which not only contains a large number of micro pores,but also provides a large specific surface area for gas adsorption,but also contains large pores and micro cracks,which provides a channel for the flow of gas in coal seams?Different coal into coal,the environment and the process is not the same,leading to pore size,shape is not the same,the pore structure can reflect the physical and chemical properties of coal from the microscopic.Therefore,it is necessary to combine the pore structure without coal metamorphism on the adsorption were studied.This paper selects six groups of different metamorphic coal samples,determination of the specific surface area of coal by using liquid nitrogen adsorption test,Kong Rong and aperture,according to the test data,to explore the different degree of metamorphism and its specific surface area,the relationship between Kong Rong and the aperture:With the degree of metamorphism increases,the total pore volume of coal appeared high low high trend,the specific surface area increased,while the average pore size of coal has changed rapidly reduced.Using gas adsorption and desorption experiment,combined with micro pore results,analyzes the influence of micro pore structure of different metamorphic degree of coal the adsorption and desorption,That the higher the degree of metamorphism of coal,the adsorption constant a values showed low high low,the adsorption constant b value decreased;the adsorption constant of coal a value of coal pore volume,pore volume,adsorption capacity is higher,the value of B is mainly affected by the micro occupied the proportion of micropores,the greater the proportion of B is lower,the desorption capacity is smaller.