Study on the formation of PM10 from high-sodium coal under gasification conditions in a flat-flame burner reactor

Abstract

The deposition of fly ash is a key problem during utilization of high-sodium coal. A flat-flame burner reactor was used to investigate PM10 formation during high-sodium coal entrained flow gasification. The results showed that all particle size of PM10 at different gasification stages exhibits bimodal distributions. It transforms from irregular soot and char particles to square NaCl, spherical aluminosilicate and irregular char particles as gasification proceeds. As gasification time increases, Na and Cl in PM0.1 increases from 20.39 % to 57.61 %, Ca and Mg in PM0.1–1 increases from 22.51 % to 38.74 %, Si and Al in PM0.1–10 increases from 36.87 % to 71.60 %. Besides, a model is established to reveal the formation mechanism of PM10. It well-predicts the PM10 yields, and demonstrates that PM0.154, PM0.154–2.47, and PM2.47–10 come from the nucleation-collision-coagulation of vaporized Na and Cl etcetera, fragmentation of Ca, Mg-contained minerals, and fragmentation and gasification of char, respectively. The results provide valuable information for understanding of PM10 formation during high-sodium coal gasification.