Influence of vitrinite and inertinite on the soot formation characteristics during coal rapid pyrolysis in a drop tube furnace

Abstract

Soot emission reduction is critical for achieving clean and efficient coal utilization. A fundamental understanding of soot formation characteristics from different coal macerals under high-temperature conditions is essential for controlling soot generation at the source. In this study, Saimengte (SMT) coal was selected as the raw material, and its macerals were separated and enriched via density gradient centrifugation. Rapid pyrolysis of different macerals was conducted in a drop tube furnace, and the resulting soot was systematically characterized using XRD, Raman spectroscopy, TEM, and TGA. The results demonstrate that vitrinite (SMT-V) generates significantly higher soot yields compared to inertinite. SMT-V-derived soot exhibits a lower degree of aromatic condensation in the inner core, leading to higher oxidation reactivity. In contrast, the outer surface develops a more ordered graphitized structure with reduced oxidation reactivity. These findings provide valuable insights into the relationship between coal macerals and their soot formation mechanisms.