Effect of ash on coal structure and combustibility

Four bituminous coals and one anthracite were used in this study. On the basis of the similar volatile matter contents of the four bituminous coals, the effects of ash in coal on the microstructure, carbonaceous structure, and chemical composition of pulverized coal were studied. Thermogravimetric analysis was used to study the effect of the addition of anthracite on the combustibility of four different bituminous coals. The results showed that with the increase of ash content in pulverized coal, the microstructure of carbon particles in coal was not much different. However, the analysis results of Raman spectroscopy and X-ray diffraction pattern showed that as the ash content increased, the degree of graphitization of coal carbonaceous structure gradually decreased. The combustibility of the four bituminous coals were better than that of the anthracite. When bituminous coal and anthracite were mixed and burned, the combustibility of the mixed sample decreased as the ash content increased.