[Effects of air staging with absorbents on trace metal during coal combustion]

Staged combustion was carried out on laboratory-scale pulverized coal combustion with different absorbents. The experiment indicated staged combustion increased emission of submicron particles, which went against the control of trace elements, especially for those of high volatile elements, such as Cu, Ni. The thermodynamics calculation also indicate the transformation of trace metal was different with different atmosphere, suboxidized and reduced species were more easily formed under reduced condition. In both conditions, absorbents show a certain absorptive ability to trace metal, and different absorbent had different ability. For unstaged combustion, kaolinite was the best for Co, Cr and Ni; dolomite for Be, and CaO for Cu. But for under staged condition, HZ- dolomite was the best for Be, Cr and Ni; Kaolinite for Co and Cu.