A scrubber is an air pollution control system.
Scrubbers are used in the removal of sulfur dioxide (SO2) and hydrogen sulfide (H2S) from flue gases. They are also used for removing carbon dioxide as part of certain variations of carbon capture and storage.
In a scrubber, the flue gases flow through a water solution spray forcing onto a slurrie of lime or limestone which react with SO2 to form solids which can be removed later.