Reductions in Volatile Organic Compound Emissions from Coal-Fired Power Plants by Combining Air Pollution Control Devices and Modified Fly Ash

The distributions and reductions of volatile organic compounds (VOCs; alkanes, aromatics, and halogenated hydrocarbons) emitted from two coal-fired power plants were compared. The partial removal of VOCs by air pollution control devices meant to reduce NOx, particulate matter, and SOx was assessed. The data show that VOC levels in flue gas were reduced by 5-35% after selective catalytic reduction, 0-40% after air preheating and electrostatic precipitation, and 10-20% after flue gas desulfurization and wet electrostatic precipitation. Adding modified fly ash was found to further reduce the effluent concentration of VOCs by 10-20%, resulting in an overall VOC reduction of 40-80%. This decrease in emissions is attributed to oxidation, deposition, condensation, and water absorption mechanisms.