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In chemistry, brown carbon (Cbrown/BrC) is brown smoke released by the combustion of organic matter. It coexists with black carbon when released in the atmosphere. [1] Black carbon is primarily released by high-temperature combustion and brown carbon is emitted mainly by biomass combustion. These two are the two most important light absorbing ...
Lignite (derived from Latin lignum meaning 'wood'), often referred to as brown coal, [1] is a soft, brown, combustible sedimentary rock formed from naturally compressed peat. It has a carbon content around 25–35% [1][2] and is considered the lowest rank of coal due to its relatively low heat content.
Young coals (brown coal, lignite) are not black. The two main black coals are bituminous, which is more abundant, and anthracite. The % carbon in coal follows the order anthracite > bituminous > lignite > brown coal. The fuel value of coal varies in the same order. Some anthracite deposits contain pure carbon in the form of graphite.
Charcoal. Charcoal is a lightweight black carbon residue produced by strongly heating wood (or other animal and plant materials) in minimal oxygen to remove all water and volatile constituents. In the traditional version of this pyrolysis process, called charcoal burning, often by forming a charcoal kiln, the heat is supplied by burning part of ...
Black carbon is in the air and circulates the globe. Black carbon travels along wind currents from Asian cities and accumulates over the Tibetan Plateau and Himalayan foothills. Chemically, black carbon (BC) is a component of fine particulate matter (PM ≤ 2.5 μm in aerodynamic diameter). Black carbon consists of pure carbon in several linked ...
The carbon group is a periodic table group consisting of carbon (C), ... The amorphous allotrope is a brown powder. The crystalline allotrope is gray and has a ...
Humus has a characteristic black or dark brown color and is an accumulation of organic carbon. Besides the three major soil horizons of (A) surface/topsoil, (B) subsoil, and (C) substratum, some soils have an organic horizon (O) on the very surface. Hard bedrock (R) is not in a strict sense soil. In classical [1] soil science, humus is the dark ...
Bituminous coal is dark brown to black, [3] hard, [9] but friable. [10] It is commonly composed of thin bands of alternating bright and dull material. [9] Though bituminous coal varies in its chemical composition, a typical composition is about 84.4% carbon, 5.4% hydrogen, 6.7% oxygen, 1.7% nitrogen, and 1.8% sulfur, on a weight basis. [11]