Eastern coal spray dryer evaluation. Final report

Development efforts for dry scrubbing technology for flue gas desulfurization (FGD) have been geared toward utility boilers burning low-sulfur western coals rather than eastern high-sulfur coals. This has been due to the low quantity of reagent and lower SO/sub 2/ removal required with the use of western coals and has contributed to the economic attractiveness of the dry scrubber system. To evaluate the use of the dry scrubber for flue gas desulfurization of eastern high-sulfur coals, the US Department of Energy contracted with the Babcock and Wilcox Company to perform a study to determine the technical and economical feasibility of such systems. The program was organized into the following tasks: (1) configuration specification and system preparation; (2) performance evaluation; (3) load-following and reliability evaluation; (4) commercial unit economic evaluation; and (5) report. The general conclusions of the program are: Effective dry scrubber operation for an eastern high-sulfur coal would include a higher stoichiometric ratio, low spray dryer approach temperature, and the optimized use of recycle material. A dry scrubber system designed for an eastern high-sulfur coal using a high-calcium lime reagent would not be economically competitive with a limestone wet scrubber system due to reagent costs. Use of an optimizedmore » furnace limestone injection system and recycle material would substantially reduce reagent costs and increase economic attractiveness of dry scrubber systems for eastern high-sulfur coals. This is in comparison to dry scrubber systems with nonlimestone injection. 10 references, 87 figures, 26 tables.« less