Trace Metals Volatilisation in Fluidised-Bed Combustion and Gasification of Coal

Coal contains most trace elements in the periodic table which are released by combustion and gasification and have tonic forms at certain concentrations. For metals namely: cadmium (Cd), lead (Pb), mercury (Hg) and zinc (Zn) were selected and multicomponent, multiphase equilibrium calculations were carried out for atmospheric and pressurised fluidised-bed operating conditions to determine which of the metals volatilise in the bed and which ones condense upon cooling the flue gases. It was also intended to determine the distribution and the form (compounds) of the trace metal species in the product streams. Some of the results are analysed and compared with the trace-metal content of atmospheric and pressurised fluidised-bed combustor effluent streams.