COAL is a combustible black or brownish-black sedimentary rock with a high amount of carbon and hydrocarbons. Coal is classified as a non-renewable energy source because it takes millions of years to form. Coal contains the energy stored by plants that lived hundreds of millions of years ago in swampy forests. Layers of dirt and rock covered the plants over millions of years. The resulting pressure and heat turned the plants into the substance we call coal.
Types of Coal
ANTHRACITE contains 86%–97% carbon and generally has the highest heating value of all ranks of coal. Anthracite is mainly used by the metals industry.
BITUMINOUS coal contains 45%–86% carbon. Bituminous coal is used to generate electricity and is an important fuel and raw material for making coking coal or use in the iron and steel industry.
SUBBITUMINOUS coal typically contains 35%–45% carbon, and it has a lower heating value than bituminous coal.
LIGNITE contains 25%–35% carbon and has the lowest energy content of all coal ranks. Lignite coal deposits tend to be relatively young and were not subjected to extreme heat or pressure. Lignite is crumbly and has high moisture content, which contributes to its low heating value. Lignite is mostly used to generate electricity.
Uses of Coal
South African Coal
Local Coal
Specifications | ||
Properties | Minimum quantity | Maximum quantity |
Moisture % | 1.23 % | 23.18 % |
Volatile Matter % | 23.28 % | 46.916 % |
Ash Content % | 3.98 % | 28.01 % |
Fixed Carbon % | 51.22 % | 70.3 % |
Total Sulfur Content % | 0.2 % | 0.7 % |
Calorific Value (K.cal/Kg) | 5115 Kcal/Kg | 7000 Kcal/Kg |
Specifications | ||
Properties | Minimum quantity | Maximum quantity |
Moisture % | 1.7 % | 50 % |
Volatile Matter % | 16.39 % | 53 % |
Ash Content % | 2.7 % | 44.2 % |
Fixed Carbon % | 14.3 % | 58.8 % |
Total Sulfur Content % | 0.4 % | 10.7 % |
Calorific Value (K.cal/Kg) | 2570 Kcal/Kg | 7000 Kcal/Kg |