セミコークスの構造分析に基づく配合効果の検討

抄録

In order to evaluate effects of low-quality coal on blending with good-quality coal for the purpose of making metallurgical coke, thermal decomposition behavior of coal blends was analyzed and the structural features of semicoke samples obtained by the heat treatment of single coal or coal blends were evaluated by solid-state NMR. Thermal behavior of coal was examined by thermogravimetric analysis, the results showing synergistic effects: blending poor-quality low rank coal with good-quality coal tended to promote thermal decomposition reaction, while blending poor-quality high-rank coal will suppress pyrolysis. NMR measurements both with single pulse excitation mode and with dipolar dephasing mode gave the distribution of various types of carbon in detail so a fraction of bridgehead aromatic carbon to total aromatic carbon could be evaluated, this being an index of the size of polycondensed aromatic hydrocarbon which would be contained in the semicoke samples. The structural parameters and the size of polycondensed aromatic hydrocarbon unit was compared between semicoke sample derived single coal and that from blended coal, the results clearly indicating synergistic blending effect. Although two different behavior was observed for two different coal blends, both cases had positive effects on the development of aromatic ring size during heating.