@cougars- There are essentially three different types of scrubbers used on a power plant.
Wet scrubbers spray water or a reagent slurry into the exhaust flu gas to cool and condense acid emissions. The harmful particles in the exhaust bond with the water or slurry, causing it to fall where plant workers can collect and ship the waste for processing.
Dry scrubbers are similar except they used chemicals and sand to trap the different particles.
The last type of scrubber is an absorbent scrubber. This type of scrubber works in a similar fashion to an HVAC filter. A filter cartridge is inserted that attracts specific types of particulate and chemical matter.