Abstract
Levels of PCDD/F production in a 140 MWth bubbling
fluidized bed boiler were measured. The boiler uses solid
recovered fuel, bark and sludge. Homologue distribution
patterns suggest the de novo mechanism is the main
pathway for the generation of dioxin and furans in the
post combustion zones of the boiler. Two modes of sulfur
addition were tested to induce the deactivation of Cu
which has been identified as the prime catalyst of this
mechanism. First, S-pellet promoted Cu sulfation as
supported by aerosol sampling data and resulted in a
decrease in PCDD/F levels. The second approach was adding
sulfur through peat; this resulted in an increase in
PCDD/F concentration. Factors such as high Cu content in
the SRF-peat-sludge fuel mixture and reduced
volatilization of Cu may have contributed to the said
increase. For all test cases, phase redistribution of
PCDD/F was observed in the electrostatic precipitator
favoring more gaseous PCDD/F at the outlet. The homologue
distribution pattern did not change in the flue gas path,
suggesting that further synthesis and/or chlorination in
the stream were minimized. There is however evidence for
subsequent reactions happening in the ESP fly ash. The
homologue distribution pattern in the latter was
different from that of the flue gas, and more highly
chlorinated PCDD/Fs were present. Furthermore, the ratio
of PCDD and PCDF was different from that of the samples
in the flue gas path.
Original language | English |
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Pages (from-to) | 677-687 |
Number of pages | 11 |
Journal | Fuel |
Volume | 134 |
DOIs | |
Publication status | Published - 2014 |
MoE publication type | A1 Journal article-refereed |
Keywords
- fluidized bed boilers
- solid recovered fuel
- copper
- sulfur addition
- electrostatic precipitators
- PCDD/F
- waste management