Find the composition of coal

Coal is formed from the remains of ancient plants that were buried in geological strata or within the Earth’s crust, undergoing a series of very complex transformations. It is a complex mixture composed of organic and inorganic substances, primarily containing carbon; in addition, it contains small amounts of elements such as hydrogen, nitrogen, sulfur, and oxygen, as well as inorganic minerals (mainly including elements like silicon, aluminum, calcium, and iron). Carbon: In our country’s peat, the dry ash-free basic carbon content ranges from 55% to 62% ； After becoming lignite, the carbon content increases to 60–76.5% ； The carbon content of bituminous coal is 77–92.7% ； Up to highly metamorphosed anthracite, the carbon content is 88.98%. Some anthracites with a higher degree of coalification have a carbon content of over 90% ； Hydrogen: As the carbon content increases from 92% to 98%, the hydrogen content decreases from 2.1% to below 1%. Generally, the hydrogen content is highest when the carbon content is between 80% and 86%. That is, in the semi-bituminous and gas-rich bituminous coal ranges of bituminous coal, the hydrogen content can reach as high as 6.5%. In the lignite and long-flame coal ranges with a carbon content of 65–80%, the hydrogen content is generally less than 6%. However, the general trend remains that as the carbon content increases, the hydrogen content decreases ； Oxygen: In lignite, when the ash-free carbon content is less than 70%, the oxygen content can be as high as over 20%. When the carbon content of bituminous coal is around 85%, its oxygen content is almost always less than 10%. When the carbon content of anthracite is above 92%, its oxygen content drops below 5% ； Nitrogen: The nitrogen content in coal is relatively low, generally ranging from 0.5 to 3.0% ；

Different types of coal have significant variations in their composition, and this can be determined in standard laboratories. The values provided in technical documents serve only as a reference range and do not have any practical significance.