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Show AFRC-JFRC Pacific Rim International Conference on Environmental Control of Combustion Processes, Oct. 1994 Uncontrolled pollutant emissions from bio11UlSS combustion under simulated boiler jUrnaceconditiOns B. M. Jenkins 1,2 and L.L. Baxter! !Combustion Research Facility, Sandia National Laboratories, Livermore, California 2Sabbatical professor from University of California, Davis Abstract Uncontrolled NOx, S02, CO, and total hydrocarbon emission factors were detennined for five types of biomass fuels burned in a laboratory furnace at varying stoichiometry without combustion air staging. The finely divided fuels were burned in a down-flow, electrically heated furnace under conditions simulating in part the furnace conditions in commerCially operating biomass-fueled power plants. Fuel nitrogen and sulfur concentrations ranged from 0.1 - 1.3% and 0.01 - 0.39% by weight, respectively. NOx emissions were observed to decline as equivalence ratio was increased from about 0.3 to 1. S02 emissions were observed to increase over the same range. CO and total hydrocarbon emissions increased sharply for most fuels beginning at about 0.7 equivalence ratio. Fuel N conversion to NOx was not determined, but the majority of the NOx is thought to derive from fuel-bound nitrogen under the conditions maintained in the furnace. Generally, total uncontrolled NOx production at similar fuel N concentration appeared to be reduced with the biomass fuels compared to coal, but the trend is only weakly supported because of the limited available data. IntroductiOn Of the renewable based power generation resources, biomass ranks second behind hydroelectricity in the U.S. Currently, biomass fuels contribute about 9 GWe to U.S. capacity (Williams and Larson, 1993). The principal fuel is wood, and virtually all of the capacity is based on combustion technologies, generally employing steam boilers. Biomass is an important resource in many other regions of the world, as, for example, the use of straw for power generation in Denmark (Nikolaisen, 1992), but more generally in less efficient and more polluting applications in the developing nations. Biomass has frequently been promoted as important in the reduction of local and global emissions of atmospheric pollutants and greenhouse gases (Wuebbles and Edmonds, 1991; Krause et al., 1992; Jenkins, et al., 1992). For many materials other than wood and sugar cane bagasse, little quantitative information exists on the emission levels or the influence of |