Effect of urea on fly ash PCDD/F concentrations in different particle sizes

The formation of dioxins in combustion systems

“…Following an analysis of incinerator flyash, Fängmark et al [142] concluded that chlorinated organics tend to be concentrated on the smaller particles. A similar result has been reported by Ruokojärvi et al [143], where the < 1.6-µm fraction was disproportionately loaded. The distribution of PCDD/F with particle size in atmospheric dust collected at four Japanese sites was examined by Kurokawa et al [144].…”

“…Mätzing et al [77] found that urea was an effective inhibitor when added to a pilot-scale furnace. Ruokojärvi et al [143] performed similar tests in a pilot furnace burning synthetic MSW, and found a diminution in PCDD/F by three quarters when 1 wt% urea was added. The same reduction was found across all particle sizes, indicating a surface reaction.…”

Emissions Minimization of Chlorinated Micropollutants in Coal Solid Waste Co‐Combustion by Primary Measures

“…Among the nitrogen-containing compounds, urea has been examined by several research teams for its PCDD/F inhibiting ability [85], [90]. Ruokojärvi mentioned that the addition of small particles urea promoted greater inhibitory effect on PCDD/F concentrations due to their large surface area [91]. A possible explanation for the inhibitory effect of the nitrogen compounds according Ruokojärvi is based on the presence of a lone pair of electrons of these compounds which can form stable complexes with the catalysing transition metals [92], [89].…”

Effect of Temperature and CaO Addition on the Removal of Polychlorinated Dibenzo-p-dioxins and Dibenzofurans in Fly Ash from a Medical Waste Incinerator

“…Adding (NH 4 ) 2 SO 4 to fuel (3%) can reduce PCDD/F emissions by 90% (Pandelova et al, 2005). The addition of urea resulted in the reduction of PCDD/F concentration by as much as 74% (Ruokojärvi et al, 2001). Sulfur is a very strong inhibitor of PCDD formation; it converts into SO 2 and reduces Cl 2 to HCl (Gullett et al, 1992).…”