Structural ordering of Pennsylvania anthracites on heat treatment to 2000-2900°C
Structural ordering of Pennsylvania anthracites on heat treatment to 2000-2900°C
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DOI：
10.1021/ef010295h
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发表时间：
2002-11-01
期刊：
影响因子：
5.3
通讯作者：
Schobert, HH
中科院分区：
文献类型：
--
作者：
Atria, JV;Rusinko, F;Schobert, HH
来自宾夕法尼亚州立大学煤炭样本库和数据库的三种宾夕法尼亚无烟煤经过热处理，温度高达 2900 摄氏度。通过X射线衍射对产物进行了表征。这些无烟煤在环境压力下通过热处理转变为石墨结构的程度明显不同。基于层间距接近石墨理想值和微晶高度发展的可石墨化性，其顺序为 DECS 21 > PSOC 1461 > PSOC 1468。到 2700 摄氏度时，层间距基本确定，因为将石墨化温度提高到 2900 摄氏度所带来的改善很小。微晶堆积继续发展；在 2900 与 2700 摄氏度时会发生显着变化。结构变化可以通过两个因素与成分相关。在热处理至 2000 摄氏度时，芳香族片材被交联剂（例如氧原子）“锁定”就位，可能会阻碍结构有序化。在较高温度（即 2700 和 2900 摄氏度）下，芳香片的重排容易程度（与其尺寸相关）是主要问题。芳香层的相对尺寸可以根据无烟煤的净氢含量来近似。 DECS-21具有最高的氧含量和最高的净氢值，在热处理至2000℃后显示出最少的有序性，但在2700或2900℃反应后显示出最好的结构发展。
Three Pennsylvania anthracites from the Penn State Coal Sample Bank and Data Base were heat-treated to temperatures to 2900 degreesC. The products were characterized by X-ray diffraction. These anthracites clearly differ in the extent to which they transform to a graphitic structure by heat treatment at ambient pressure. Graphitizability, based on approach of interlayer spacing to the ideal value for graphite and development of crystallite height, is in the order DECS 21 > PSOC 1461 > PSOC 1468. By 2700 degreesC the interlayer spacing is largely established, since improvements by increasing graphitization temperature to 2900 degreesC are small. The crystallite stacking continues to develop; significant changes are achieved at 2900 vs 2700 degreesC. The structural changes can be related to composition via two factors. In heat treatment to 2000 degreesC, the structural ordering may be impeded by a "locking" of aromatic sheets in place by cross-linkers, such as oxygen atoms. At the higher temperatures, i.e., 2700 and 2900 degreesC, the ease of rearrangement of aromatic sheets, which is related to their size, is the dominant issue. The relative sizes of aromatic sheets can be approximated from the net hydrogen content of the anthracites. DECS-21, which has both the highest oxygen content and the highest net hydrogen value, shows the least order after heat treatment to 2000 degreesC, but the best structural development after reaction at 2700 or 2900 degreesC.