Formation of fine particles (PM10) from Zhundong high‑sodium coal at entrained flow gasification condition in a flat-flame burner reactor

Zhundong coal has very high content of alkali metals and alkaline earth metals (AAEMs), which produces much particulate matter (PM) during combustion and gasification, resulting in many ash related problems. Fine PM with aerodynamic size less than 10 μm (PM10) during entrained flow gasification is a critical factor which affects deposition behavior of fly ash in syngas heat exchanger. In this work, a novel flat-flame assisted entrained flow reactor was used to characterize formation of PM10 from Zhundong high‑sodium coal under entrained flow gasification. Results show that the mass concentration particle size distribution (PSD) curves of PM10 exhibited three peaks at 0.0308 μm, 0.255 μm, and 2.47 μm, respectively. NaCl and sodium aluminosilicate were mainly enriched in PM0.1 (fine PM with aerodynamic size less than 0.1 μm). Besides, the increase of water vapor ratio in volume decreased the mass concentration yield of PM10, while it promoted the number concentration yield of PM0.1. In addition, three particle formation modes of PM10 were observed in the mass fraction size distribution curves of Al. The particle size ranges of PM10 in the ultrafine, central and coarse modes and their formation mechanisms from Zhundong high‑sodium coal at entrained flow gasification condition were identified.