Fate of Trace Metals in a Rotary Kiln Incinerator with a Venturi/Packed Column Scrubber. Volume 1. Technical Results

摘要

A five week series of pilot-scale incineration tests, using a synthetic waste feed, was performed at the Environmental Protection Agency's Incineration Research Facility to evaluate the fate of trace metals fed to a rotary kiln incinerator. Eight tests studied the fate of five hazardous constituent and four nonhazardous constituent trace metals as a function of incinerator operating temperatures and feed chlorine content. Three tests evaluated the valence state of chromium in emissions and discharges as a function of feed valence state and feed chlorine content. Parametric tests confirmed that cadmium, lead and bismuth are relatively volatile, based on normalized discharge distribution data. Barium, copper, strontium, chromium and magnesium are relatively nonvolatile. Apparent scrubber efficiencies generally correlated with observed volatilities; collection efficiency was higher for nonvolatile metals than for volatile metals. Increased feed chlorine content significantly increased the volatility of cadmium, lead and bismuth. Chromium test results indicated that, with no feed chlorine, 95% of the measured chromium is discharged in the kiln ash. With chlorine in the feed, this fraction dropped to 85%. Kiln ash contained negligible hexavalent chromium Cr(+6) for all tests. The fraction of scrubber exit flue gas chromium as Cr(+6) was nominally 15% with no feed chlorine, increasing to 50% with chlorine-containing feed.