High resolution TEM image analysis of anthracite coal microcrystalline structure

Four HRTEM images of Yangquan No. 3 anthracite were quantitatively characterized, including fringe length, orientation and stacking distribution. The result indicates that the fringe characteristics are consistent with the coal rank characteristics of anthracite. The fringe of three different microcrystalline regions in image 1 was statistically analyzed. In region 1, the average fringe length is 0.87 nm, the overall fringe orientation distribution is disorderly, but there is still a small range of orderly arrangement between the short fringes and between the long fringes, and the maximum number of stacking layers is 4; In region 3, the fringe length is 1.01 nm on average, the orientation is higher in the range of 135°−180° with a ratio of 62.46%, and the maximum number of stacking layers can reach 6. The fringe distribution characteristic of region 2 is between 1 and 3. Most of the fringes are curved, and there may be heterocyclic rings and aliphatic rings. The FT-IR and ¹³C NMR data show that the aliphatic structure mainly exists in the form of aliphatic rings, which plays an important role in the process of forming long fringes by short fringes.