ADVANCED FLUE GAS CONDITIONING AS A RETROFIT UPGRADE TO ENHANCE PM COLLECTION FROM COAL-FIRED ELECTRIC UTILITY BOILERS

The U.S. Department of Energy and ADA Environmental Solutions are engaged in a project to develop commercial flue gas conditioning additives. The objective is to develop conditioning agents that can help improve particulate control performance of smaller or under-sized electrostatic precipitators on utility coal-fired boilers. The new chemicals will be used to control both the electrical resistivity and the adhesion or cohesivity of the fly ash. There is a need to provide cost-effective and safer alternatives to traditional flue gas conditioning with SO{sub 3} and ammonia. During this reporting quarter, performance testing of flue gas conditioning was completed at the PacifiCorp Jim Bridger Power Plant. The product tested, ADA-43, was a combination resistivity modifier with cohesivity polymers. The product was effective as a flue gas conditioner. However, ongoing problems with in-duct deposition resulting from the flue gas conditioning were not entirely resolved. Primarily these problems were the result of difficulties encountered with retrofit of an existing spray humidification system. Eventually it proved necessary to replace all of the original injection lances and to manually bypass the PLC-based air/liquid feed control. This yielded substantial improvement in spray atomization and system reliability. However, the plant opted not to install a permanent system. Also in this quarter, preparations continued for a test of the cohesivity additives at the American Electric Power Conesville Plant, Unit 3. This plant fires a bituminous coal and has opacity and particulate emissions performance issues related to fly ash re-entrainment. Ammonia conditioning is employed here on one unit, but there is interest in liquid cohesivity additives as a safer alternative