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Coal tar is produced through thermal destruction of coal.Its composition varies with the process and type of coal used – lignite, bituminous or anthracite. [13]Coal tar is a mixture of approximately 10,000 chemicals, of which only about 50% have been identified.
One can produce a tar-like substance from corn stalks by heating them in a microwave oven. This process is known as pyrolysis. Tar is a dark brown or black viscous liquid of hydrocarbons and free carbon, obtained from a wide variety of organic materials through destructive distillation. Tar can be produced from coal, wood, petroleum, or peat. [1]
Pitch is a viscoelastic polymer which can be natural or manufactured, derived from petroleum, coal tar, [1] or plants. Pitch produced from petroleum may be called bitumen or asphalt , while plant-derived pitch, a resin , is known as rosin in its solid form.
In industrial chemistry, coal gasification is the process of producing syngas—a mixture consisting primarily of carbon monoxide (CO), hydrogen (H 2), carbon dioxide (CO 2), methane (CH 4), and water vapour (H 2 O)—from coal and water, air and/or oxygen. Historically, coal was gasified to produce coal gas, also known as "town gas".
Bitumen (asphalt or coal-tar pitch) is a material made up of organic liquids that are highly sticky, viscous, and waterproof. [1] Systems incorporating bituminous-based substrates are sometimes used to construct roofs, in the form of "roofing felt" or "roll roofing" products.
Bituminous coal. Bituminous coal, or black coal, is a type of coal containing a tar-like substance called bitumen or asphalt. Its coloration can be black or sometimes dark brown; often there are well-defined bands of bright and dull material within the seams. It is typically hard but friable.
The term creosote has a broad range of definitions depending on the origin of the coal tar oil and end-use of the material. With respect to wood preservatives, the United States Environmental Protection Agency (EPA) considers the term creosote to mean a pesticide for use as a wood preservative meeting the American Wood Protection Association (AWPA) Standards P1/P13 and P2. [6]
The mining and processing of coal causes air and water pollution. [124] Coal-powered plants emit nitrogen oxides, sulfur dioxide, particulate pollution, and heavy metals, which adversely affect human health. [124] Coal bed methane extraction is important to avoid mining accidents. The deadly London smog was caused primarily by the heavy use of ...