Field Evaluation of Novel Approach for Obtaining Metal Emission Data (Subtask 4.24)

Abstract

Over the past two decades, emissions of mercury, nonmercury metals, and acid gases from energy generation and chemical production have increasingly become an environmental concern. On February 16, 2012, the U.S. Environmental Protection Agency (EPA) promulgated the Mercury and Air Toxics Standards (MATS) to reduce mercury, nonmercury metals, and HCl emissions from coal-fired power plants. The current reference methods for trace metals and halogens are wet-chemistry methods, EPA Method (M) 29 and M26A, respectively. As a possible alternative to EPA M29 and M26A, the Energy & Environmental Research Center (EERC) has developed a novel multielement sorbent trap (ME-ST) method to be used to sample for trace elements and/or halogens. Testing was conducted at three different power plants, and the results show that for halogens, the ME-ST halogen (ME-ST-H) method did not show any significant bias compared to EPA M26A and appears to be a potential candidate to serve as an alternative to the reference method. For metals, the ME-ST metals (ME-ST-M) method offers a lower detection limit compared to EPA M29 and generally produced comparable data for Sb, As, Be, Cd, Co, Hg, and Se. Both the ME-ST-M and M29 had problems associated with high blanks for Ni, Pb, Cr, and Mn. Although this problem has been greatly reduced through improved trap design and material selection, additional research is still needed to explore possible longer sampling durations and/or selection of lower background materials before the ME-ST-M can be considered as a potential alternative method for all the trace metals listed in MATS.