Coal Handling

Coal, a fossil fuel, is the largest source of energy for the generation of electricity worldwide, as well as one of the largest worldwide anthropogenic sources of carbon dioxide emissions. Gross carbon dioxide emissions from coal usage are slightly more than those from petroleum and about double the amount from natural gas. Coal is extracted from the ground by mining, either underground or in open pits.

Dust is a fine powdered form of coal, which is created by the crushing, grinding, or pulverizing of coal. Because of the brittle nature of coal, coal dust can be created during mining, transportation, or by mechanically handling coal.

Ash is the very fine portion or ash residue that results from the combustion of coal. The fly ash portion is usually removed electrostatically from the coal combustion gasses before they are released to the atmosphere. About 31 percent of the 57 million metric tons produced annually in the United States are beneficially used; the remainder must be disposed of in ponds or landfills.



Ship Unloader
Borneo is field of coal and it is delivery by ship to many power station like in Java. Usually before the rain season begin on October, The Power Station in Indonesia should be many stock of coal to avoid the ship can't lay to jetty due to high wind speed. Normally the save coal stock in the yard (stock pile) should be enough for two weeks at full load operation. After the ship is lay to jetty, the coal handling operator is starting to hard work for unloading coal from ship by heavy equipment like ship un-loader and dozer. So faster so good.


Stacker Reclaimer
After Ship Unloader, the coal is travelling by conveyor to stock pile. It devided by section of kind of coal like low and high calorie or others reason by stacker reclaimer. The process is called reclaiming. And then from stock pile is transfer to crusher building then to Silo called stacking process and Tripper Car is equipment to devide coal also maintain silo level above 60%.


Crusher
Most crushers employ a combination of all these crushing methods.

Impact: In crushing terminology, impact refers to the sharp, instantaneous collision of one moving object against another. Both objects may be moving, such as a baseball bat connecting with a fast ball, or one object may be motionless, such as a golf ball being driven off a tee.

Attrition: Attrition is a term applied to the reduction of materials by scrubbing it between two hard surfaces. Hammermills operate with close clearances between the hammers and the screen bars, and they reduce by attrition combined with shear and impact reduction. Though attrition consumes more power and increases wear on hammers and screen bars, it is practical for crushing less abrasive materials such as pure limestone and coal.


Shear: Shear consists of a trimming or cleaving action rather than the rubbing action associated with attrition. Shear is usually combined with other methods. For example, single-roll crushers employ shear together with impact and compression.

Compression: As the name implies, crushing by compression is done between two surfaces, with the work being done by one or both surfaces. Jaw crushers using this method of compression are suitable for reducing extremely hard and abrasive rock.

More information about coal process, please click http://idpowerstation.blogspot.com/2011/08/coal-process.html

Related link :
AshTech Corporation
Ash handling system
Crusher Theory
Electrosatic Precipitator