Dioxin and furan formation in FBC boilers

Fluidized bed combustion (FBC) is increasingly being used for municipal sol id waste incineration and for various applications in which dioxin and fura n (PCDD/F) formation are concerns. Despite the fact that fluidized bed comb ustion is a relatively low temperature system, current evidence shows that they perform relatively well. One hypothesis is that sulfur, which is conta ined in some of the fuels used in FBC (e.g. coal in cofiring situations), h elps to reduce dioxin production. This paper endeavors to examine this spec ulation and finds that such benefits depend on the CI/S ratio and that at h igher sulfur addition levels dioxins, furans, and polycyclic aromatic hydro carbon (PAH) production may actually increase. This and the reasons for it are discussed.