Full-Scale Test Evaluation of a Multielement Sorbent Trap Sampling Method for Halogen and Trace Metal Emissions at an Illinois Coal-Fired Plant

摘要

The Mercury and Air Toxics Standards require monitoring and more frequent measurement of halogens and metals to verify compliance. The only acceptable U.S. Environmental Protection Agency (EPA) reference methods involve a series of wet impingers containing hazardous chemicals. The Energy & Environmental Research Center's Center for Air Toxic Metals® has developed a multielement sorbent trap (MEST)-based method as an alternative to EPA Methods 29 and 26A that greatly simplifies on-site sampling and recovery requirements, with samples shipped to a laboratory for overnight analysis or analyzed on-site. This method does not require liquid chemicals to be brought on-site, which speeds up the sampling process and reduces the probability of sample contamination. A program is under way to evaluate the MEST method at various power plants. Full-scale sampling was completed at two Illinois coal-fired power plants. Data from these samples for the MEST were compared to EPA M26A and M29 halogen and trace metal data. HC1 measurement data for the MEST method and EPA M26A compared well, with most of the data being within 10%. The measurement data for metals was much more variable between the MEST and EPA M29 methods, generally within 50%, with some elements (Pb and Cd) being more variable because of relatively high background levels. The test program demonstrated that the MEST method could be employed at the two Illinois coal-fired plants providing results that were consistent and relatively similar to EPA reference methods.