Coal grade info.. FYISince I didnt really know the difference I thought maybe everyone would also be interested in this info.
anthracite" is the highest rank of coal, a nearly pure form of carbon with low levels of moisture and contaminants (ash and volatiles). It is a hard, black coal usually with carbon content of 86-98%, energy content values in excess of 30,000 kJ/kg (12, 600 BTUs/lb), and moisture content less than 15% by weight. Anthracite is rare and is used primarily by the metallurgical and chemical industries as a carbon additive, but is also used for domestic heating purposes.
"bituminous coal" is a black coal with moisture content generally less than 15% by weight and calorific values ranging from 27,000-33,000 kJ/kg (10,500-14,000 BTUs/lb). Bituminous coal can be either a metallurgical or thermal coal as it can be used for both coke production and power generation.
"coke" means the substance formed when coking coal is heated in a coking oven to a very high temperature in the absence of
"lignite" is the lowest ranked coal. Often called "soft" or "brown" coal, it is a brownish-black coal with carbon content of 25-35%. It has energy values ranging from 15,000-20,000 kJ/kg (6,300-8,300 BTUs/lb) and high moisture content of up to 45% by weight. Lignite is strictly a thermal coal and is used as a fuel in power generating plants.
"sub-bituminous coal" is a black coal with carbon content of 35-45%, energy content values in the range of 20,000-27,000 kJ/kg (8,300-10,500 BTUs/lb) and moisture content generally between 20% and 30% by weight. Sub-bituminous coal generally has a lower sulphur content which makes it attractive for combustion purposes. It is primarily used as a fuel source in thermal power plants and for industrial heating purposes.
Energy content varies widely even among the same grades of coal. A typical ton of bituminous coal will yield 22-26 million BTU. Depending on the efficiency of the production facility, this can yield anywhere from 2,000 to 4,000 kilowatt-hours of electricity.