Role of Sulfur in Reducing PCDD and PCDF Formation

摘要: Past research has suggested that the presence of sulfur (S) in municipal waste combustors (MWCs) can decrease downstream formation chlorinated organic compounds, particularly polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs). Thus, co-firing a MWC with coal, because S species from may reduce PCDD PCDF emissions. Experiments were carried out to test this hypothesis determine role S. A field-sampled fly ash was injected into EPA's pilot-scale reactor, doped hydrogen chloride (HCl). The tests involved either natural gas or coal combustion. Besides combustion environment, injection temperature sulfur-to-chlorine ratio (S/CI) varied. Flue sampled analyzed for in-flight formation. In natural-gas-fired when added (as dioxide, SO 2 ), decreased dramatically at S/Cl ratios as low 0.64, varying furnace conditions, inhibitory effect consistent about 1. coal-fired furnace, again observed values 0.8 1.2, respectively, two coals tested. inhibition mechanisms studied bench-scale reactor. Results show depletion molecular chlorine (Cl an active chlorinating agent, by through gas-phase reaction appears be significant mechanism addition previously reported deactivation copper catalysts.