Study on soot-sodium interaction in the initial stage during pulverized coal combustion

Study on the interaction between soot and alkali metals is critical for deep insight into particle formation and evolution mechanisms in the initial stage of pulverized coal combustion. In this work, fine particles derived by ZD and its acid-washed samples at different atmospheres were analyzed using Hencken burner and ELPI+. It was found that Na doping was significant for the soot derived by ZD coal, which was almost oxidized and replaced by mineral particles at 20% O₂ condition. After acid wash, soot yield was increased by 40% and the oxidation rate was lowered, resulting in the enrichment of soot in fine particles at 20% O₂ condition. Microstructures of Na-doped soot was examined by HRTEM and the result suggested the multiple interaction mechanisms between alkali metals and heavy hydrocarbon during secondary reaction of volatile.