MERCURY CAPTURE BY AN ACTIVATED CARBON IN A FIXED-BED BENCH-SCALE SYSTEM

The control of mercury emissions for utility power plants may become i mportant because of the Clean Air Act Amendments requirement that the U.S. Environmental Protection Agency (EPA) assess the health risks ass ociated with these emissions [1]. One approach for mercury removal, wh ich may be relatively simple to retrofit (compared to other methods [2 -4]), is the injection of sorbents, such as activated carbon, upstream of existing particulate control devices. A study, sponsored by the El ectric Power Research Institute (EPRI) and the U.S. Depart ment of Ene rgy (DOE), is being conducted at the University of North Dakota Energy & Environmental Research Center (EERC) to develop a sorbent-screening test protocol, screen potential mercury sorbents in a bench-scale fix ed-bed system and provide data to support efforts to model mercury cap ture mechanisms. A proper protocol is required to establish repeatabil ity of the results and ensure reproducibility of results between diffe rent labs. To date, elemental mercury tests have been completed with s everal sorbents and under various flue gas conditions. The carbon-base d sorbent used in this study was a lignite-based activated carbon (LAC ), commercially available from American Norit Co., Inc. This paper pre sents results from the more recent tests with the LAC sorbent and elem ental mercury. The LAC sorbent has also been used by others as a basel ine sorbent [5-7].