What are common air pollution reduction methods used with coal burning power plants?

• A. Vapor recovery nozzles
• B. Photochemical reactors
• C. Catalytic converters
• D. Scrubbers, electrostatic precipitators, baghouse filters

Answer: (D)

Coal-fired power plants mainly need to treat the exhaust to remove both gaseous pollutants and tiny particles before it goes into the atmosphere. The most common setup uses scrubbers to reduce sulfur dioxide and particulate control devices like electrostatic precipitators and baghouse filters to capture solid particles. A scrubber — typically a wet limestone system — neutralizes and removes SO2 from the flue gas, often producing gypsum as a byproduct. Electrostatic precipitators apply a high voltage to charge particles in the gas stream so they can be collected on oppositely charged plates, effectively pulling out fly ash and other particulates. Baghouse filters use fabric bags to physically trap particles as the gas passes through, delivering very high particulate removal efficiency, especially for fine particles. Together, these methods address the major pollutants produced by burning coal.

Vapor recovery nozzles are used to capture fuel vapors at filling operations, not in stack gas cleanup. Photochemical reactors aren’t standard for coal plants, and catalytic converters are typical for vehicles, not large stationary power stations.