Open AccessPILOT-AND FULL-SCALE DEMONSTRATION OF ADVANCED MERCURY CONTROL TECHNOLOGIES FOR LIGNITE-FIRED POWER PLANTS
Author(s) -
Steven A. Benson,
Charlene R. Crocker,
Kevin C. Galbreath,
Jay R Gunderson,
Mike J Holmes,
Jason D Laumb,
Michelle R. Olderbak,
John H. Pavlish,
Yan Li,
Ye Zhuang,
Jill M Zola
Publication year - 2004
Language(s) - English
Resource type - Reports
DOI - 10.2172/836113
Subject(s) - scrubber , mercury (programming language) , flue gas , wet scrubber , sorbent , environmental science , waste management , combustion , environmental chemistry , elemental mercury , chemistry , environmental engineering , engineering , adsorption , organic chemistry , computer science , programming language
North Dakota lignite-fired power plants have shown a limited ability to control mercury emissions in currently installed electrostatic precipitators (ESPs), dry scrubbers, and wet scrubbers (1). This low level of control can be attributed to the high proportions of Hg{sup 0} present in the flue gas. Speciation of Hg in flue gases analyzed as part of the U.S. Environmental Protection Agency (EPA) information collection request (ICR) for Hg data showed that Hg{sup 0} ranged from 56% to 96% and oxidized mercury ranged from 4% to 44%. The Hg emitted from power plants firing North Dakota lignites ranged from 45% to 91% of the total Hg, with the emitted Hg being greater than 85% elemental. The higher levels of oxidized mercury were only found in a fluidized-bed combustion system. Typically, the form of Hg in the pulverized and cyclone-fired units was dominated by Hg{sup 0} at greater than 85%, and the average amount of Hg{sup 0} emitted from North Dakota power plants was 6.7 lb/TBtu (1, 2). The overall objective of this Energy & Environmental Research Center (EERC) project is to develop and evaluate advanced and innovative concepts for controlling Hg emissions from North Dakota lignite-fired power plants by 50%-90% at costs of one-half to three-fourths of current estimated costs. The specific objectives are focused on determining the feasibility of the following technologies: Hg oxidation for increased Hg capture in wet and dry scrubbers, incorporation of additives and technologies that enhance Hg sorbent effectiveness in ESPs and baghouses, the use of amended silicates in lignite-derived flue gases for Hg capture, and the use of Hg adsorbents within a baghouse. The scientific approach to solving the problems associated with controlling Hg emissions from lignite-fired power plants involves conducting testing of the following processes and technologies that have shown promise on a bench, pilot, or field scale: (1) activated carbon injection (ACI) upstream of an ESP combined with sorbent enhancement, (2) Hg oxidation and control using wet and dry scrubbers, (3) enhanced oxidation at a full-scale power plant using tire-derived fuel (TDF) and oxidizing catalysts, and (4) testing of Hg control technologies in the Advanced Hybrid{trademark} filter insert