Coal dust
From Wikipedia, the free encyclopedia
Coal dust is a fine powdered form of coal. Because of the brittle nature of coal, coal dust can be created during mining, transportation, or by mechanically handling coal.
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[edit] Risks
[edit] Explosions
Coal dust suspended in air is explosive. Coal dust has far more surface area per unit weight than chunks of coal, and is more susceptible to spontaneous combustion. As a result, a nearly empty coal store is a greater explosion risk than a full one. The worst mining accidents in history have been caused by coal dust explosions, such as the disaster at Senghenydd in South Wales in 1914. Such mining accidents were usually initiated by firedamp ignitions, the shock wave of which raised dust from the floor of the mine galleries to make an explosive mixture. The Luisenthal Mine Disaster and the explosion at Benxihu Colliery are two examples of this type of explosion caused by coal dust.
The main attempts at prevention include using safety lamps, adding stone dust coffers to mine galleries, and watering workings.
[edit] Lung and skin problems
Coal workers' Pneumoconiosis, or black lung disease, is caused by inhaling coal dust, typically dust produced in coal mining.
According to George Orwell, coal miners could develop characteristic tattoos owing to coal dust getting into wounds. This can also occur with substances like gunpowder.
[edit] Coal dust in energy generation
For use in thermal power plants, coal is ground into dust using a device called a powdered coal mill [1]. The resulting product, called powdered coal or pulverized coal, is then generally used in a fossil fuel power plant for electricity generation. Pulverised coal is a significant dust explosion hazard, as large quantities are suspended in air for transfer from the mill to the power plant. Explosions have occurred when the flow drops and flames in the burning chamber pass back along the ductwork delivering fuel.
