FGD Additives to Segregate and Sequester Mercury in Solid Byproducts

Coal, an abundant and low-cost source of energy, is used to generate more than half of the electricity in the United States. However, coal has a range of environmental disadvantages, which include emissions of mercury via the flue gas and environmental releases of mercury during the subsequent processing and disposal of byproducts. This project will develop new technology for controlling mercury emissions and environmental releases associated with the operation of coal-fired electric power generation plants and the processing of byproducts. This control will be achieved through the use of chemical additives in the power plant¿s flue gas desulfurization (FGD) system. These additives will: (1) sequester mercury into the liquid phase; (2) prevent mercury re-emissions into the flue gas; (3) prevent precipitation and adsorption of mercury on primary FGD byproducts such as gypsum; and (4) precipitate mercury from the FGD blow down stream, as a stable solid byproduct that is segregated from other FGD solid byproducts. Commercial Applications and other Benefits as described by the awardee: The technology should have extensive commercial applications in the electric utility industry at both new and existing coal-fired power plants equipped with wet FGD scrubbing systems. Manufacturers that process FGD byproducts will avoid mercury exposure and environmental releases. The public would benefit through reduced exposure to mercury emitted from power plant stacks and from reduced exposure to mercury-containing FGD byproducts.