Effect of boiler output on trace element partitioning during coal combustion in two fluidised-bed power stations

The main aim of this study was a detailed comparison of trace element parti tioning during combustion of bituminous coal and lignite in two circulating fluidised-bed units at 40 and 100% boiler output. The elements considered here are: S, Cl, Br, V, Cr, Co, Ni, Cu, Zn, Ge, As, Se, Sn, Sb, W, Hg, and Pb. The trace element concentrations in combustion products show enrichment of most of the elements in fly ash related to bottom ash as well as the sl ight element enrichment in fly ash at 40% boiler output compared with the 1 00% output. Using an element balance calculation the proportion of each ele ment in bottom ash, fly ash and emissions was determined. Results showed th at at both boiler outputs the highest relative percentages of elements that entered into emissions were Hg and Cl. (C) 2001 Elsevier Science Ltd. All rights reserved.