采用低温氮吸附法和扫描电子显微镜,研究了氮气干燥、空气干燥、热压干燥前后煤样的孔隙结构和表面特性,同时对干燥后煤样进行了复吸试验研究。结果表明:氮气干燥和空气干燥后煤样的比表面积、孔容和平均孔径均增大;热压干燥后煤样的比表面积和孔容降低,平均孔径增大。扫描电镜显示,空气干燥和氮气干燥后煤颗粒表面更加不平整,裂缝变大、孔洞增多;而热压干燥后煤样表面变得平滑,裂缝被挤压在一起,孔洞减少。复吸试验结果表明:干燥后煤样复吸25 h后,复吸曲线趋于平缓,氮气干燥和空气干燥煤样复吸后的水分在13%左右,热压干燥煤样复吸后水分为9%,且热压干燥煤样的水分复吸速率较小。

The low temperature nitrogen adsorption method and the scanning electron microscope was applied to study the porous structure and surface features 0 f the coal sample before and after the nitrogen gas drying,air dry and thermal press dry and the study of the re-adsorption was conducted on the coal samples after drie d.The results showed that the specific surface area, pore volume and pore average diameter of the coal sample after the nitrogen air dry and air dry were increased.The specific surface area,pore volume and pore average diameter of the coal sample after thermal press dry were increased.the scanning electron microscope showed that the particle surface of the coal sample after the air dry and nitrogen dry was more uneven,the cracks became larger and the pores were increased. after the thermal pre ss dry,the surface of the coal samples became flat and smooth,the cracks were squeezed together and the pores were reduced. The re-adsorption experiment results sh owed that after 25 h re-adsorption of the coal sample dried,the re-adsorption curve was flat in tendency,the moisture content after the re-adsorption of the coal sample after the nitrogen dry and air dry was about 13% ,the moisture content of the coal sample after the thermal press dry was 9% and the moisture re-adsorption rate of the t hermal press dry coal sample was lower.

国家重点基础研究发展计划(973计划)资助项目(2012CB214902)；国家自然科学基金资助项目(51104159)；