Appearance of trace elements in co-firing fuels

With the implementation of new EU guidelines the levels of max. allowable emission levels of Cd, Tl, Hg, Sb, As, Pb, Cr, Co, Cu, Mn, Ni, V will be further restricted.  This may have implications for co-​combustion of coal with waste derived fuels.  In this study chem. fractionation, i.e. a stepwise leaching procedure has been applied on coal, peat, sewage sludge, bark, impregnated wood and forest residue.  With this method fuels are leached in three steps, i.e. leached with water, ammonium acetate and hydro chloric acid, resp.  Both soly. in different leaching agents of main ash forming matter and the trace elements Cd, Tl, Hg, Sb, As, Pb, Cr, Co, Cu, Mn, Ni, V and Zn were studied.  In this way more information became available about the characteristics of co-​firing fuels.  Thermodn. calcns. were used to show the consequences of the interaction with main ash forming elements on the partition of Cd, Hg, Pb and Zn in the gas​/ash phase.