| Slide 5 of 20 |
| Fossil energies | ||||
 |
||||
| The origin of coal involves burial compaction and induration of plant material. The process begins in extensive swamps. Plant material produced in the swamp decomposes to form peat. Subsidence causes the peat to be buried with sediment, and the resulting increase in temperature and pressure compacts the peat, expelling water and gases and thus forming lignite and brown coals. With continued subsidence and deeper burial, the lignite is compressed into bituminous coal. Further compression drives out most of teh remaining hydrogen, nitrogen, and oxygen, producing anthracite coal.
Coal is important for the immediate future of our modern society because there are reasonalby large reserves of it. The trouble is that coal industry will bring serious environmental problems. |
||||
| Peat: 50% carbon | ||||
| Lignite: 72% | ||||
| Bituminous: 85% | ||||
| Anthracite: 93% | ||||