What is the purpose of 'scrubbers' on coal-fired power plants?

• A. Scrubbers remove sulfur dioxide and other pollutants from flue gas.
• B. Scrubbers increase CO2 emissions.
• C. Scrubbers cool the exhaust.
• D. Scrubbers filter water.

Answer: (A)

Scrubbers are used to remove pollutants from the flue gas produced by burning coal, with sulfur dioxide being the primary target. When coal containing sulfur is burned, sulfur compounds form SO2 in the exhaust. A wet scrubber brings a slurry, usually lime or limestone, into contact with that hot gas. The SO2 reacts with the slurry and is converted into a solid byproduct such as gypsum, which is then captured, dramatically reducing how much SO2 escapes to the atmosphere. This helps plants meet environmental regulations and reduces acid rain potential. Scrubbers don’t increase CO2 emissions, and they aren’t designed to cool the exhaust or filter water.