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ALTERNATIVES TO CALCIUM-BASED SO2 SORBENTS FOR FLUIDIZED-BED COMBUSTION: CONCEPTUAL EVALUATION
Citation:
Newby, R. AND D. Keairns. ALTERNATIVES TO CALCIUM-BASED SO2 SORBENTS FOR FLUIDIZED-BED COMBUSTION: CONCEPTUAL EVALUATION. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/7-78/005.
Description:
The report gives results of a conceptual engineering evaluation to screen supported metal oxides as alternatives to natural calcium-based sorbents (limestones and dolomites) for SO2 control in atmospheric and pressurized fluidized-bed combustion (FBC) processes. Alternative sorbents were evaluated, using three acceptance criteria: SO2 removal capability in the combustor, predicted by thermodynamics; SO2 concentrations achievable in the regenerator off-gas, according to thermodynamics; and SO2 concentrations off the regenerator, achievable based on material and energy balances. The evaluation identified 14 potentially acceptable sorbents for atmospheric FBC, and 11 for pressurized FBC. Cost estimates were prepared to project the maximum acceptable loss rates for the alternative sorbents due to attrition and/or deactivation. Loss rates must be less than 0.1% of bed inventory per hour in order to compete economically with natural calcium-based sorbents, even if maximum thermodynamic performance were obtained. U.S. resources of some minerals may be of extreme importance for many of the alternative metal oxide sorbents considered.