Evaluation of Air Toxics Emissions from RDF Slurry Combustion

A process has been developed for producing a pumpable slurry fuel from refuse-derived fuel (RDF). A target application for this fuel is cofiring with fossil fuels in utility boilers. Pilot scale tests were conducted to characterize the emissions of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/PCDFs) and trace metals from carbonized RDF slurry combustion. Total PCDD/PCDF concentration averaged 0.38 ng/dscm at 7% O 2 for two test runs. Mercury, cadmium, and lead had average emission concentrations of 0.0066, 0.0017, and 0.035 mg/dscm at 7% O 2 , respectively. While nearly all mercury was found to be in the vapor phase, emissions were low due to low mercury concentration in the fuel itself. Cadmium and lead were evidently in the solid phase and were effectively captured by the ESP. In general, the results indicate that the carbonized RDF slurry would be expected to meet promulgated new source performance standards (NSPS) for municipal waste combustion and make an effective fuel for cofiring in utility boilers.