XRD analysis of carbon stacking structure in coal during heat treatment

• Published in: Fuel (Guildford) Vol. 83; no. 17; pp. 2427 - 2433
• Main Authors: Takagi, H., Maruyama, K., Yoshizawa, N., Yamada, Y., Sato, Y.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.12.2004; Elsevier
• Subjects: Applied sciences; Caking coal; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Fuels; Heating rate; Non-caking coal; Stacking structure; X-ray diffraction; X-ray diffraction; Non-caking coal; Stacking structure; Caking coal; Heating rate; Heat treatment; Crystallinity; Volatiles; Standards; Crystallites; Analysis method; Fluidity; Heating; X ray diffractometry; Coal rank
• ISSN: 0016-2361; 1873-7153
• DOI: 10.1016/j.fuel.2004.06.019

The fraction of the stacking structure ( P s) and the average number of aromatic layers ( N ave) in several raw coals were estimated by X-ray diffraction analysis (Standard Analysis of Coal by XRD: STAC-XRD). STAC-XRD is more appropriate for analyzing coal with low crystallinity than the classical XRD analysis method by using the interlayer spacing of aromatic layers ( d 002) and the mean crystallite size along the c axis ( L c ). STAC-XRD was also used to compare the development of the stacking structure in caking coal during heat treatment with that in non-caking coal. After heat treatment at 920 °C, N ave of the caking coals was larger than that of the non-caking coals. The stacking of the aromatic layers in the caking coal temporarily developed at the fluidity stage at 400–440 °C, but in the 440–600 °C range, the release of volatile components partially disordered the stacked layers. The influence of heat-treatment conditions on carbon stacking structure in several kinds of coal was investigated by means of STAC-XRD. The heating rate required for the development of stacking structure in lower-rank coals was slower than that required for higher-rank coals.