"The set of technologies used to remove sulfur dioxide (SO2) from exhaust flue gases of fossil-fuel power plants, is called Flue-gas desulfurization. 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. For a typical coal-fired power station, flue-gas desulfurization (FGD) may remove 95 percent or more of the SO2 in the flue gases. Fossil fuels such as coal and oil contain a significant amount of sulfur. When fossil fuels are burned, about 95 percent or more of the sulfur is generally converted to sulfur dioxide (SO
2). Such conversion happens under normal conditions of temperature and of oxygen present in the flue gas. However, there are circumstances, under which such reaction may not occur. Most FGD systems employ two stages: one for fly ash removal and the other for SO2 removal. Attempts have been made to remove both the fly ash and SO2 in one scrubbing vessel. Another important design consideration associated with wet FGD systems is that the flue gas exiting the absorber is saturated with water and still contains some SO2.
Last date updated on July, 2014