Study of Fundamentals of Mercury Speciation in Coal-Fired Boilers under Simulated211 Post-Combustion Conditions

摘要

The report discusses a continuation of the study on mercury speciation initiated211u001ein fiscal year 1997 (FY97). Efforts were made in the FY98 study to better 211u001eunderstand the speciation behavior of mercury under conditions simulating coal-211u001efired boilers more closely than those for the FY97 study. In the followup FY98 211u001ework, calcium oxide (CaO) was added to the model fly ashes containing three 211u001ecomponents which were tested previously. The rate of oxidation of elemental 211u001emercury with four-component ashes was found to be much slower than that achieved 211u001ewith the three-component ashes. The detrimental effect of CaO on the Deacon 211u001ereaction catalysts of CuO and Fe203 was demonstrated. Elemental mercury oxidation 211u001eover three field-collected coal fly ash samples was studied, and only one sample 211u001econtaining high iron and copper content exhibited modest elemental mercury 211u001eoxidation activity. A field-collected cement kiln dust sample containing 29 wt% 211u001ecalcium (Ca) exhibited catalytic behavior of oxidized elemental mercury similar 211u001eto that of a Ca-containing model fly ash tested in FY97. The elemental mercury 211u001eoxidation activity of cuprous chloride (CuC1) was investigated.