화학공학소재연구정보센터
Biomass & Bioenergy, Vol.6, No.4, 243-260, 1994
BIOMASS FUELED FLUIDIZED-BED COMBUSTION - ATMOSPHERIC EMISSIONS, EMISSION CONTROL DEVICES AND ENVIRONMENTAL-REGULATIONS
Fluidized bed combustors have become the technological choice for power generation from biomass fuels in California. Atmospheric emission data obtained during compliance tests are compared for five operating 18 to 32 MW fluidized bed combustion power plants. The discussion focuses on the impact of fuel properties and boiler design criteria on the emission of pollutants, the efficiency of pollution control devices, and regulations affecting atmospheric emissions. Stack NO(x) emission factors are shown not to vary substantially among the five plants which burn fuels with nitrogen concentrations between 0.3 and 1.1% dry weight. With reference to previous work, it is suggested that fuel nitrogen to NO(x) conversion rates gradually level off at fuel nitrogen concentrations above 0.15%. Prompt NO(x) formation mechanisms are suggested to be important in addition to fuel NO(x) mechanisms, compensating for reduced formation of thermal NO(x) in fluidized bed combustors. This may limit the extent to which NO(x) formation can be controlled in the boiler. All facilities use at least one particular control device, but not all use limestone injection or other control techniques for sulfur and chlorine. The lack of control for chlorine suggests the potential for emission of toxic species due to favorable temperature conditions existing in the particulate control devices, particularly when burning fuels containing high concentrations of chlorine.