Control of Nitrogen Oxide Emissions: Selective Catalytic Reduction (SCR)

The Clean Coal Technology (CCT) Demonstration Program is a government and industry co-funded effort to demonstrate a new generation of innovative coal utilization processes in a series of " showcase " facilities built across the country. These projects are on a scale sufficiently large to demonstrate commercial worthiness and to generate data for design, construction, operation, and technical/economic evaluation of full-scale commercial applications. The goal of the CCT program is to furnish the U.S. energy marketplace with a number of advanced, more efficient , and environmentally responsible coal-utilizing technologies. These technologies will mitigate the economic and environmental impediments that limit the full utilization of coal as a continuing viable energy resource. To achieve this goal, a multi-phased effort consisting of five separate solicitations was administered by the U.S. Department of Energy (DOE). Projects selected through these solicita-tions have demonstrated technology options with the potential to meet the needs of energy markets and respond to relevant environmental requirements. Part of this program is the demonstration of technologies designed to reduce emissions of oxides of nitrogen (NO x) from existing coal-fired utility boilers. NO x is an acid rain precursor and a contributor to atmospheric ozone formation, which is a health hazard and is also related to smog formation. NO x emissions are regulated under the provisions of the Clean Air Act and particularly the Clean Air Act Amendments (CAAA) of 1990. This report discusses a CCT project which demonstrated selective catalytic reduction (SCR) technology for the control of NO x emissions from high-sulfur, coal-fired boilers. The project was conducted by Southern Company Services, which served as a cofunder and as the host at Gulf Power Company's Plant Crist near Pensacola, Florida. Other participants and cofunders were the Electric Power Research Institute (EPRI) and Ontario Hydro. DOE provided 40% of the total project cost of $23 million. The project was administered for DOE by its Federal Energy Technology Center (FETC). The SCR process consists of injecting ammonia (NH 3) into boiler flue gas and passing the flue gas through a catalyst bed where the NO x and NH 3 react to form nitrogen and water vapor. The objectives of the demonstration project were to investigate: • Performance of a wide variety of SCR catalyst compositions, geom-etries, and manufacturing methods at typical U.S. high-sulfur coal-fired utility operating conditions. • Catalyst resistance to poisoning by trace metal species present in U.S. coals that may …