Mass balance and partitioning of trace elements under oxy-coal combustion: First experiences

Mass balance and partitioning of inorganic trace pollutants have been evaluated at the largest oxy-Pulverised Coal Combustion (oxy-PCC) demonstration plant to date owned by Fundación Ciudad de la Energía (CIUDEN). Results reveal that the concentration of gaseous SO2, B, Se, F, and HCl increases progressively in the CO2-rich flue gas along the depuration train. This results in negative retention efficiencies of these types of pollutants and in the enrichment of trace elements in the oxy-fly ashes (oxy-FAs). These two factors affected the MB closure for highly volatile S, Cl, and F, and moderately volatile with high condensation potential B, As, and Se over the oxy-PCC and whole installation. This first experience has lead us to focusing further work on 1) elucidating the behaviour of inorganic trace pollutants in the CO2-rich flue gas after a number of CO2-rich flue gas re-circulations back to the boiler; and 2) investigating the speciation and leaching potential of inorganic trace pollutants, especially F, retained in the oxy-FAs in order to establishing remediation actions if required.