Sub-bituminous coal

Sub-bituminous coal is a type of coal whose properties range from those of lignite to those of bituminous coal and are used primarily as fuel for steam-electric power generation.

Properties

Sub-bituminous coals may be dull, dark brown to black, soft and crumbly at the lower end of the range, to bright jet-black, hard, and relatively strong at the upper end. They contain 15-30% inherent moisture by weight and are non-coking (undergo little swelling upon heating).^[1] The heat content of sub-bituminous coals range from 8300 to 11,500 BTu/lb or 19,306 to 26,749 kJ/kg. Their relatively low density and high water content renders some types of sub-bituminous coals susceptible to spontaneous combustion if not packed densely during storage in order to exclude free air flow.

Reserves

A major source of sub-bituminous coal in the United States is the Powder River Basin in Wyoming.

Current use

Sub-bituminous coals, in the United States, typically have a sulfur content less than 1% by weight, which makes them an attractive choice for power plants to reduce SO₂ emissions under the Acid Rain Program.

See also

• Types of Coal
• Acid Rain Program
• List of CO2 emitted per million Btu of energy from various fuels

References

1. ↑ The Babcock & Wilcox Company. Steam: its generation and use. The Babcock & Wilcox Company. pp. 36–5. ISBN 0-9634570-1-2. 

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