PCDD/F prevention by novel inhibitors: Addition of inorganic S- and N-compounds in the fuel before combustion

The objectives of this work were to study the addition of sulfur and nitrog en containing compounds to the fuel before the combustion, to examine their capacity for preventing PCDD/F emissions, to investigate their influence o n the PCDD/F homologue patterns and to determine the most effective additiv e concentration used for inhibition. Various sulfur and nitrogen containing solid compounds were mixed with Refuse Derived Fuel (RDF) in proportions o f 10% w/w of the fuel, and the mixtures were combusted in a lab-scale react or at 1000 degreesC. Analysis and quantification of PCDD/F showed that inor ganic sulfur containing compounds significantly affected PCDD/F emissions, resulting in more than 98% reduction of toxic compounds. However, urea pres ented a lower prevention capacity and resulted in about 28% reduction of PC DD/Fs. High PCDD/F prevention efficiencies, about 96%, were also obtained d uring the combustion of a mixture containing 1% w/w of amidosulfonic acid ( ASA) used as the additive. In addition, the presence of sulfur and nitrogen containing compounds affected the PCDD/F formation pathways, as it was obs erved from the PCDD/F ratios and the homologue profiles. The PCDD/F prevent ion ability of sulfur containing compounds is discussed; it could be attrib uted to the formation of sulfur-copper complexes.