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Show Alliance Research Center a McDermott company ) Atmospheric Fluidized Bed Combustion Babcock & Wilcox Modifying the combustion process is one way to control the emission of sulfur dioxide, nitric oxides, and particulates into the atmosphere. The Atmospheric Fluidized Bed Combustion (AFBC) facility at the Alliance Research Center is an example of process modification. A F B C mixes finely crushed coal and limestone and fluidizes the mixture by blowing hot combustion air through it. W h e n the mixture burns, much of the coal's sulfur is captured by the limestone and a solid by-product is formed which can be removed with the ash. Tests at the facility have achieved combustion efficiency in the 98 to 99 percent range through the use of a recycle process. With recycle, some particles of unburned carbon are re-injected into the Fluidized Bed to achieve high combustion efficiency. Recent tests at the A F B C facility successfully achieved a major reduction in nitrogen oxide formation during combustion. This development has reduced nitrogen oxide emission levels in the Fluidized Bed to less than one-fourth of the current Environmental Protection Agency (EPA) allowable limits. The two-megawatt test facility- which measures 6 feet by 6 feet in cross-section-has already proven effective in meeting E P A standards for sulfur dioxide capture during the combustion of high sulfur coals. The A F B C process is being developed as a new boiler concept to provide electric utilities with an alternative to conventional pulverized coal boilers, which must be equipped with sulfur dioxide scrubbers to clean flue gas after combustion. The facility has served as the basis for the design of a 20-megawatt pilot facility n o w under construction for the Tennessee Valley Authority and the Electric Power Research Institute. Alliance's Fluidized Bed test facility has been in operation since 1978 and has operated for more than 6,000 hours. B&W's Fluidized Bed Development Facility-which measures 6 feet by 6 feet-is jointly sponsored by the Electric Power Research Institute and the company. WATER JACKET VENTI GAS DISCHARGE • TEAM DRUM fREElOAAD GRAVIMETRIC COAL • LIMESTONE FEEDERS AIR OISTRI.UTOR AIR HEATER ASH CONVEYOR Fluidized Bed Combustion Development Facility Babcock & Wilcox Alliance Research Center Division General Office 1562 Beeson Street Alliance, O H 44601 |