Relationship between chemical structure of caking additives produced from low rank coals and coke strength

Abstract

Coke strength can be enhanced by adding HyperCoals (HPC). HPC can be produced from different rank of coals including low rank coals. The aim of this study is to investigate and evaluate the usability of HPC from low rank coals as caking additive. In this paper, 1H-NMR, solid state 13C-NMR analysis, and elemental analysis were carried out to investigate the molecular structure of HPC prepared from low rank coals. The results showed that the number of aromatic rings in a unit structure increased from 1-2 in original coals to 2-3 in HPC extracted at 360°C. Effect of extraction temperature was also investigated and it was found that fraction of 3 aromatic rings increased in HPC extracted at 400°C in comparison to HPC extracted at 360 °C. The strength of cokes produced by adding HPC was directly a function of number of aromatic rings in the HPC and increased with increasing number of rings.