OFF-GAS MERCURY CONTROL USING SULFUR-IMPREGNATED ACTIVATED CARBON - TEST RESULTS

摘要

Several laboratory and pilot-scale tests since the year 2000 have included demonstrations of off-gas mercury control using fixed bed, sulfur-impregnated activated carbon. These demonstrations have included operation of carbon beds with gas streams containing a wide range of mercury and other gas species concentrations representing off-gas from several U.S. Department of Energy (DOE) mixed waste treatment processes, including electrical resistance heated (joule-heated) glass melters, fluidized bed calciners, and fluidized bed steam reformers. Surrogates of various DOE mixed waste streams (and surrogates of off-gas from DOE mixed waste streams) including liquid "sodium bearing waste" (SBW) located at the Idaho National Laboratory (INL), liquid "low activity waste" (LAW) from the Hanford Site, and liquid waste from Savannah River Site ("Tank 48H waste") have been tested. Test results demonstrate mercury control efficiencies up to 99.999%, high enough to comply with the Hazardous Waste Combustor (HWC) Maximum Achievable Control Technology (MACT) standards even when the waste feed mercury content would have introduced uncontrolled off-gas mercury concentrations exceeding 400,000 μg/dscm (at 7% O_2) if unmitigated, and confirm carbon bed design parameters for such high efficiencies. Results of several different pilot-scale and engineering-scale test programs performed over several years are presented and compared.