Effect of combustion temperature on the emission of trace elements under O2/CO2 atmosphere during coal combustion

The effect of combustion temperature on the emission of trace elementswas studied under O-2/CO2 atmosphere during coal combustion in a laboratory scale fluidized bed combustor. The elemental composition of fine fly ash particles collected with a low pressure impactor(LPI) was quantified by X-Ray Fluorescence Spectrometer (XRF). The elemental composition of coal and bottom ash was quantified byinductively coupled plasma-atomic emission spectroscopy (ICP-AES). The results indicate that the contents of Mn, Zn, Cd and Cr in the fly ash increase with the rise of combustion temperature. It is found that the enrichment of Zn and Cd is greater in the submicrometer particles than the supermicrometer particles, but Mn and Cr do not enrich in the submicrometer particles. Mn, Zn, Cd and Cr display one peak around 0.1 mu m. The relative enrichment factor (R-ij) of four elements is in the order of Zn, Cd, Mn and Cr. Zn and Cd are mostly retained in fly ashwhileMn and Cr are retained in both the fly ash and bottom ash.