Flue-gas desulfurization (FGD) is a set of technologies used to remove sulfur dioxide () from exhaust flue gases of fossil-fuel power plants, and from the emissions of other sulfur oxide emitting processes such as waste incineration, petroleum refineries, cement and lime kilns. Methods Since stringent environmental regulations limiting emissions have been enacted in many countries, is being removed from flue gases by a variety of methods. Common methods used: Wet scrubbing using a slurry of alkaline sorbent, usually limestone or lime, or seawater to scrub gases; Spray-dry scrubbing using similar sorbent slurries; Wet sulfuric acid process recovering sulfur in the form of commercial quality sulfuric acid; SNOX Flue gas desulfurization removes sulfur dioxide, nitrogen oxides and particulates from flue gases; Dry sorbent injection systems that introduce powdered hydrated lime (or other sorbent material) into exhaust ducts to eliminate and from process emissions. For a typical coal-fired power station, flue-gas desulfurization (FGD) may remove 90 percent or more of the in the flue gases. History Methods of removing sulfur dioxide from boiler and furnace exhaust gases have been studied for over 150 years. Early ideas for flue gas desulfurization were established in England around 1850. With the construction of large-scale power plants in England in the 1920s, the problems associated with large volumes of from a single site began to concern the public. The emissions problem did not receive much attention until 1929, when the House of Lords upheld the claim of a landowner against the Barton Electricity Works of the Manchester Corporation for damages to his land resulting from emissions. Shortly thereafter, a press campaign was launched against the erection of power plants within the confines of London. This outcry led to the imposition of controls on all such power plants. The first major FGD unit at a utility was installed in 1931 at Battersea Power Station, owned by London Power Company. In 1935, an FGD system similar to that installed at Battersea went into service at Swansea Power Station. The third major FGD system was installed in 1938 at Fulham Power Station. These three early large-scale FGD installations were suspended during World War II, because the characteristic white vapour plumes would have aided location by enemy aircraft. The FGD plant at Battersea was recommissioned after the war and, together with FGD plant at the new Bankside B power station opposite the City of London, operated until the stations closed