The report discusses, for a coal-burning power plant, using humidification of the flue gas in a low-temperature duct to increase SO2 removal by dry calcium-based sorbents. In particular, humidification may be a desirable modification of EPA's LIMB process, which is based on injecting limestone or hydrated lime in the furnace; it could augment SO2 removal by adding post-furnace removal to that occurring in the injection zone. The report covers work in post-furnace humidification, charge-augmented humidification, water vapor adsorption by lime (with and without additives), and mathematical modeling of humidification and SO2 removal processes. From these investigations, it was concluded that, for enhancement of SO2 capture at the Edgewater demonstration of LIMB, humidification by a water spray will be required. A spray of pure water would suffice if the frequency of collisions between sorbent particles and water droplets could be increased. Deliquescent additives that are known to enhance SO2 capture by Ca(OH)2 at low temperatures must operate to some extent by mechanisms other than deliquescence.

EPA project officer, Louis S. Hovis. "At head of title: Project summary." "September 1989." "EPA/600-S7-89-001."