Kinetics and heating rates effects on coal devolatilization during pyrolysis

Coal type, particle size, and, most importantly, the heating rate under which it occurs influence the degree of swelling and plasticity. The heating method, whether rapid or slow, can significantly impact the pyrolysis characteristics, volatile matter content, softening, devolatilization, and resolidification of coals. As the heating rate increased during pyrolysis, the devolatilization rate shifted to higher temperatures, leading to an increase in both T_max and R_max. The activation energy for the primary devolatilization stage increased with increasing heating rates (53.7–59.7 kJ/mol) but decreased for the secondary devolatilization stage (47.6–45.7 kJ/mol), respectively. This trend of results suggests that coal macromolecules decompose more quickly at higher heating rates. However, this study mimicked the coking conditions in the blast furnace by using low heating rates. Future work will consider more coal samples with distinct rheological and petrographic properties.