Lignite may be described as a soft, low-rank, brownish-black coal. Lignite is referred to as brown coal. Lignite is a sedimentary rock that is formed from naturally compressed peat. It is regarded as the lowest rank of coal, mainly due to its low heat content. Lignite is commonly used as a fuel in power plants.
Lignite is a combustible rock that is composed of consolidated and altered vegetal remains. It is the result of an accumulation of partially decayed material (peat), which is buried by other sediments. The decayed plant material is slowly turned into coal (lignite) due to the geothermal energy and pressure.
The carbon content of lignite varies from 25 to 35%; the moisture content of this rock is very high. Lignite is extensively used as a fuel for steam-electric power generation, catering to a large portion of the electricity needs across the world.
Mining of Lignite
Lignite is mined by surface mining. In surface mining, the material lying on the mineral deposits are removed, and the underlying mineral deposits are exposed for extraction. The stripping of the overlying material is done using draglines and motorized scrapers. Once lignite is exposed, it is extracted with a hydraulic backhoe and loaded into trucks before being transported.
Characteristics of Lignite
The typical characteristics of lignite are listed below:
- Brownish-black in color
- Soft and moist
- Easily combustible
- Energy content varies from 10 to 20 MJ/kg
- Easily converted into gas
Benefits of Lignite
Some of the benefits of lignite are:
- Abundantly available
- Reliable generation of electricity
- Environment-friendly power generation
- Low-cost electricity production
Sources and Further Reading