COAL DUST EXPLOSION HAZARDS AT COAL BURNING ELECTRICAL POWER PLANTS

摘要

The explosion hazard of airborne coal dust is well known and hundreds of devastating explosions have occurred and continue to occur in underground coal mines throughout the world. These explosions are usually initiated by a buildup of methane gas but a major secondary coal dust explosion will occur involving the coal dust that builds up on the mine floor and walls, unless enough inert (rock) dust is added to the coal to render the mixture inert. This same coal is used in many industrial plants to provide fuel for electrical power generation, cement and other manufacturing processes. So it is not surprising that explosions have occurred inside process equipment including bunkers, silos and pulverizers. The Chemical Safety Board report1 on combustible dusts identified 23 reported combustible dust incidents between 1980 and 2005 that involved coal dust. One particularly devastating incident occurred in a power plant in Dearborn, MI in 1999 resulting in six fatalities, 38 injuries, and about one billion dollars in property damage. Significant accumulations of coal dust throughout the plant contributed to the severity of the incident. Despite the history, coal dust explosion incidents continue to occur, for example in August of 2008 an unplanned outage at a newly commissioned Western power plant lead to an explosion that ripped open a silo and damaged two others. An explosion occurred while performing maintenance operations on a silo at a power plant in Wisconsin in 2009 and recently fires and explosions were reported in Wyoming that injured three employees and in the Ukraine that resulted in massive property loss and death to one employee.