Preliminary results from In-Duct Scrubbing Pilot Study testing

A low-cost, moderate-removal-efficiency, flue gas desulfurization (FGD) technology was selected by the Department of Energy for demonstration in its Acid Rain Precursor Control Technology Initiative. The process, identified as In-Duct Scrubbing (IDS), applied rotary atomizer techniques developed for lime-based spray dryer FGD while utilizing existing flue gas ductwork and particulate collectors. In-Duct Scrubbing technology is anticipated to result in a dry desulfurization process with a moderate removal efficiency (50% or greater) for high-sulfur coal-fired boilers. The critical elements for successful application are (i) adequate mixing of sorbent with the flue gas for efficient reactant contact, (ii) sufficient residence time to produce a non-wetting product, and (iii) appropriate ductwork cross-sectional area to prevent deposition of wet reaction products before particle drying is complete. This paper presents the IDS technology and the status of a jointly sponsored In-Duct Scrubbing Pilot Study that is being tested at the Muskingum River Plant of the American Electric Power System.