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Experiments were carried out to investigate the rapid pyrolysis of Nei-meng (NM) lignite, Shen-fu (SF) bituminous coal, and Jin-cheng (JS) anthracite with the duration time of 0–500 ms and the temperature of 1173–1773 K using a high-frequency induction furnace. Interest was centered on the primary fragmental characteristics of particles, including the changes of mass loss, particle density, and size distribution, during the pyrolysis. A pair of fragmental parameters, i.e., dimensionless particle diameter δ and particle distribution S f, was proposed to characterize the fragmentation during the different stages of pyrolysis. The result showed that the pyrolysis progress increases with time and temperature. The fragmentation extent is also positively related to the time and temperature. The progress of primary fragmentation is lignite ≈ bituminous coal > anthracite. However, the particle morphology changes little during the pyrolysis fragmentation. Evidence reveals that major fragmentations of NM and SF occur at the outer zone of the particle and the coarse fragmentation of JS is insignificant compared to the exfoliation.

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Rapid pyrolysis of coal–water slurries (CWSs) and parent coals were performed in a rapid pyrolysis reactor for three typical Chinese coals (lignite, anthracite, and a petroleum coke as reference). The pyrolysis temperatures ranged from 600 to 1200 °C with an interval of 100 °C. Samples were fed into the reactor within 1.5 min, and the pyrolysis time was controlled to 2 min. The effects of temperature on the yields of char were investigated. As CWS gasification processes usually utilize bituminous coal as feedstock, the structure of chars obtained from Shenfu bituminous coals were characterized by using XRD and BET N2 gas adsorption, and the CO2 gasification reactivity of the chars was examined by using thermogravimetric analysis (TGA). The results show that, as the pyrolysis temperature increases, the char pyrolysis yields differ between CWS and parent coals, in which there is a competition between steam–coal/char reaction and water evaporation in the process. For the Shenfu bituminous coal, the degree of graphitization and the regularity of the microcrystalline structure of CWS chars were slightly higher than those of the parent coal chars, and the specific surface areas of the CWS chars were much higher than those of the parent coal chars. The gasification reactivity of the CWS chars was also higher than that of parent coal chars.