TYPES OF COAL

                                            CONVENTIONAL SOURCE OF ENERGY-COAL

                       TYPES OF COAL

As geological processes apply pressure to dead biotic material over time, under suitable conditions, its metamorphic grade increases successively into:

• Peat, considered to be a precursor of coal, which has industrial importance as a fuel in some regions, for example, Ireland and Finland (In its dehydrated form, peat is a highly effective absorbent for fuel and oil spills on land and water, and also used as a conditioner for soil to make it more able to retain and slowly release water.)
• Lignite, or brown coal, the lowest rank of coal, used almost exclusively as fuel for electric power generation
  • Jet, a compact form of lignite, sometimes polished; used as an ornamental stone since the Upper Palaeolithic
• Sub-bituminous coal, whose properties range between those of lignite and those of bituminous coal (It is used primarily as fuel for steam-electric power generation and is also an important source of light aromatic hydrocarbons for the chemical synthesis industry.)
• Bituminous coal, a dense sedimentary rock, usually black, but sometimes dark brown, often with well-defined bands of bright and dull material (It is used primarily as fuel in steam-electric power generation, with substantial quantities used for heat and power applications in manufacturing and to make coke.)
• Anthracite, the highest rank of coal (It is a harder, glossy black coal used primarily for residential and commercial space heating; it may be divided further into metamorphically altered bituminous coal and "petrified oil", as from the deposits in Pennsylvania.)