Pending legislation suggests there will be a need for increased removal of NOx, SO2, Hg (Mercury) and PM 2.5 from coal-fired power plants. Current commercial technologies only handle one of these pollutants so several different technologies must be combined to remove all of these pollutants. The Pahlman™ Process developed by Enviroscrub Technologies removes NOx, SO2 and Hg in one step. The Pahlman™ Process is a sorbent-based technology, which utilizes a proprietary Oxides of Manganese compound to remove SO2, NOx and Hg. The sorbent is spray-dried into the exhaust duct downstream of the current particulate control device. Spray drying is used to control the particle size (40 micron mean) and increases the surface area of the particle (∼300 m2 /gram). The sorbent is collected in a fabric filter baghouse, which serves two purposes: (1) it captures the entrained sorbent and (2) provides additional residence time for gas-solid contact between the sorbent and the target pollutants. The loaded sorbent is removed from the baghouse and routed to regeneration. Sorbent regeneration occurs in an aqueous solution under temperature and pressure while the solution is maintained in the proper pH and Eh ranges. The reacted manganese is oxidized back to its starting state and sulfate and nitrate byproduct compounds are produced. The insoluble oxides of manganese are then filtered out of the solution and returned to the spray-dryer for re-use. The soluble sulfate and nitrate compounds are separated and the nitrate by-products are sold as fertilizer. The sulfates are further processed and re-used in the regeneration process with excess sulfate by-products sold as fertilizer or used to produce sulfuric acid. Testing over the last three years has resulted in consistent SO2 removal of over 99% and NOx removal of greater than 95%. Testing performed in June 2003 at DTE Energy’s River Rouge Power Station Unit#3 in Detroit, Michigan showed removal rates of >99% for SO2, >98% for NOx and 97% for oxidized Mercury (Hg2+). Mercury testing was performed by the Energy and Environmental Research Center (EERC) and paid for by DTE Energy and the DOE. Testing performed in December 2003 through January 2004 at Minnesota Power’s Boswell Energy Center Unit#4 in Cohasset, Minnesota showed removal rates of >98% for SO2, >94% for NOx and 99.2% for elemental (Hg0) and 94% for total Mercury (HgT).

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