What is coal? Formation and types

What is Coal? a combustible black or brownish-black sedimentary rock composed mostly of carbon and hydrocarbons. It is the most abundant fossil fuel produced in the United States. a nonrenewable energy source because it takes millions of years to create. The energy in coal comes from the energy stored by plants that lived hundreds of millions of years ago, when the Earth was partly covered with swampy forests.

How Coal Forms coal is an organic sedimentary rock It is an accumulation and preservation of plant materials, usually in a swamp environment When plant debris dies and falls into the swamp the standing water of the swamp protects it from decay. Swamp waters are usually deficient in oxygen, which would react with the plant debris and cause it to decay. This lack of oxygen allows the plant debris to persist.

Formation of Coal overtime

What is Coal? Coal is classified into five main types, or ranks: peat anthracite, bituminous, subbituminous, lignite

Peat A mass of recently accumulated to partially carbonized plant debris. Peat is an organic sediment. Burial, compaction and coalification will transform it into coal, a rock. It has a carbon content of less than 60% on a dry ash-free basis.

Lignite is the lowest rank of coal with the lowest energy content. Lignite coal deposits tend to be relatively young coal deposits that were not subjected to extreme heat or pressure, containing 25%-35% carbon. Lignite is crumbly and has high moisture content. Also know as brown coal. Most lignite is mined in Texas and North Dakota. Lignite is mainly burned at power plants to generate electricity.

contains 45-86% carbon. Bituminous coal was formed under high heat and pressure. Bituminous coal in the United States is between 100 to 300 million years old. It is the most abundant rank of coal found in the United States, accounting for about half of U.S. coal production. West Virginia, Kentucky, and Pennsylvania are the largest producers of bituminous coal. Bituminous coal

Subbituminous coal has a lower heating value than bituminous coal. Subbituminous coal typically contains 35-45% carbon. Most subbituminous coal in the United States is at least 100 million years old. Wyoming is the leading source of subbituminous coal.

contains 86-97% carbon, and generally has a heating value slightly higher than bituminous coal. All of the anthracite mines in the United States are located in northeastern Pennsylvania. Anthracite