基于压汞法的焦作矿区无烟煤孔隙特征研究OA

Coal pore structure serves as the main storage space and migration pathway for gas.To clarify the pore structure character-istics of anthracite in Jiaozuo Mining Area,mercury intrusion porosimetry was adopted to investigate the pore structure features of soft coal and hard coal.The complex pore structure inside coal samples was revealed,and the differences in pore structure paramet-ers such as pore area,pore volume and pore size distribution between soft coal and hard coal were analyzed.The results show that visible pores and fractures in hard coal constitute the major portion of the total pore volume,accounting for 23.55%-63.72%,where-as this proportion in soft coal is considerably lower,only 3.18%-30.82%.The volumes of small pores,mesopores and macropores in soft coal are generally higher than those in hard coal,reflecting the difference in pore development degree between the two.The pore areas of soft coal and hard coal are concentrated in the range of 5.5-100 nm,which contributes 94.3%-99.7%of the total pore area,indicating that this pore size range plays a dominant role in the pore structure.Among them,micropore area accounts for a consider-able proportion of 52.5%-78.13%,while the total area of mesopores and macropores is relatively small,only 0.3%-5.7%,and the contribution of visible pores and fractures to pore area is negligible.The mercury intrusion and extrusion curves of soft coal do not coincide,indicating that soft coal contains more open pores and ink-bottle-shaped pores compared with hard coal.In contrast,the mercury intrusion-extrusion curves of hard coal are highly overlapping,proving that hard coal has better pore connectivity than soft coal.The average pore size measured by mercury intrusion porosimetry is 34.8 nm for soft coal and 35.6 nm for hard coal,showing little difference between the two,both fluctuating within the range of 20.1-58.5 nm.