Method of convert a double-loop flue gas desulfurization system to a single-loop system

A method for converting a double-loop flue gas desulfurization system to a single-loop desulfurization system includes removing the deep packing from the scrubber housing and replacing the packing with a thin tray having a plurality of perforations. The return line which connects the bowl is removed from the feed tank; and a plurality of openings, apertures or perforations are provided in the shroud ring and the bowl of the housing in order to permit slurry to pass from upper spray headers to the bottom of the housing as well as permit flue gas flow upwardly through the housing to the flue gas outlet. The lower spray headers are removed from the housing and the feed line connected to the lower spray headers is reconnected to the feed tank for providing the single-loop. An oxidation air system is provided in the feed tank for creating an in-situ forced oxidation system.