Characterisation of fly ash from fluidised bed combustors with regard to its utilisation and safe disposal
Fly ash from three coal burning fluidised bed combustors (a 4 MWth Atmospheric Fluidised Bed Boiler (TNO AFBB), a 90 MWth Atmospheric Fluidised Bed Boiler (AKZO AFBB) and a 226 MWth Circulating Fluidised Bed Combustor (DSBG CFBC)) is studied. The morphology of the fly ash, its bulk chemical composition and the composition and thickness of the surface layers are determined. Carbon tends to accumulate mainly in the samples from the cyclones (TNO AFBB). The highest concentrations of carbon occur in middle large fractions 20-35 µm size (TNO AFBB); in samples from the AKZO AFBB and the DSBG CFBC they occur in fractions of much finer size (7-10 µm). Most of the trace elements accumulate in the fine fly ash from the bag filter (TNO AFBB). The trace elements in the final residue from all three combustors show on the whole an inverse concentration-particle size dependence. Many of them are enriched on the surface of the fly ash particles. In some cases they are also localised as distinct particles among the fly ash particles. The fly ashes from all three combustors show no appreciable bio-toxic effects. The concentration of trace elements and PAHs in all fly ash samples investigated are below the threshold values mentioned in the Dutch Chemical Waste Act.
Bibliographic Reference: EUR 12789 EN (1990) 90 pp., MF, ECU 4
Record Number: 199010753 / Last updated on: 1994-12-01
Original language: en
Available languages: en