Flue Gas Desulphurization Systems remove sulfur dioxide from coal or other sulfur containing fuels. Roots type blowers or centrifugal blowers provide air and mixing to allow effective
removal of the byproducts of this process. To do this, a water slurry of ground limestone is used to absorb the SO2 from flue gas. The flue gas is directed to a spray tower (or absorber) where the
slurry is sprayed over the flue gas. The dissolved SO2 forms calcium sulfite. Forced oxidation from Roots type blowers or centrifugal blowers oxidizes the calcium sulfite into calcium sulfate. This
byproduct can be land filled or sold as gypsum for building materials.