A SO2scrubber system is the informal name for flue gas desulfurization (FGD) technology, which removes, or “scrubs,” SO2 emissions from the exhaust of coal-fired power plants. A scrubber works by spraying a wet slurry of limestone into a large chamber where the calcium in the limestone reacts with the SO2 in the flue gas. There are some variations in the design of scrubbers. For example, some scrubbers may use other chemicals such as lime or magnesium oxide to react with the SO2in the flue gas.