ABSTRACT
Eight types of coals of different rank were selected and their fundamental combustion characteristics were examined along with the conversion of volatile nitrogen (N) to nitrogen oxides (NOx)/fuel N to NOx. The activation energy, onset temperature, and burnout temperature were obtained from the differential thermogravimetry curve and Arrhenius plot, which were derived through thermogravimetric analysis. In addition, to derive the combustion of volatile N to NOx/fuel N to NOx, the coal sample, which was pretreated at various temperatures, was burned, and the results were compared with previously derived fundamental combustion characteristics. The authors' experimental results confirmed that coal rank was highly correlated with the combustion of volatile N to NOx/fuel N to NOx.
Low-rank coals are abundant in several regions throughout the world. However, despite their quantity and relatively low market price, these low-rank coals have not been used because of a lack of existing studies. Therefore, this paper presents the characteristics of NOx emission and fundamental combustion on coal combustion with coals having different rank to investigate the effect of coal rank on coal combustion.