Scrubbers for removal of SO/sub 2/ from industrial boiler flue gas

The purpose of this paper is to review proven systems commercially available for removing SO/sub 2/ from flue gases emitted from industrial boilers. The application of SO/sub 2/ removal systems to coal-fired industrial boilers results in very high capital cost additions to a project and produces substantially higher operating costs. In making or selecting SO/sub 2/ removal equipment, several systems are available and should be examined. Final selection may depend on specifics of the location and availability of reagents. Of available systems that have a proven history, the lime/limestone and dual alkali systems should certainly receive considerations. Of systems that are under development, the dry scrubber seems to have great potential. It is lower in cost, much simpler to operate, and therefore lower in operation and maintenance costs. This system has shown totally acceptable results on western fuels. Acceptance of this system by regulatory authorities for universal use could result in lower total industry costs for SO/sub 2/ gas cleanup. Each by-product system such as the Wellman-Lord should be carefully examined, particularly on the larger installations.