Development of a Method for the Speciation of Source Mercury Emissions

摘要

In a study conducted at the Research Triangle Institute (RTI), funded through anEPA cooperative agreement, RTI and EPA researchers sought to identify a stationary source mercury (Hg) speciation method that is applicable to both fossil fuel and waste combustion processes. Initial research included the bench-scale evaluation of EPA Method 29, as well as the identification of other potential impinger solution reagents and methods capable of selectively capturing and preserving mercury species. A relatively simple speciation/collection approach for Hg emissions from fossil fuel combustion was developed that employed impingers containing deionized water (Draft Method 101B) upstream of the Method 29 peroxide solution. Recent work by RTI and EPA has focused on the evaluation of a dilute sodium hydroxide impinger solution to replace the water used in Draft Method 101B. Results obtained to date from both bench tests and pilot-scale combustion tests indicate that the alkaline mercury speciation method (AMS) is highly effective at speciating elemental and ionic mercury emissions in the presence of Cl2 concentrations up to 20 ppmv and SO2 levels exceeding 1,500 ppmv. Other potential interferences investigated during the study were hydrogen chloride, nitric oxide, carbon dioxide, and moisture.