Coal, Charcoal and Coke: What Could Be the Difference Between Them?

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Although their uses are the same, these substances are quite different. Could it be their name or it might be something else?

Coal, charcoal, and coke are simple terms, but with an important application in our lives. The common thing for these three substances is the fact that they are used in thermocentrals, by putting machines into function through their capacity of burning as a combustible. Although they are similar in use, they are quite different through several aspects, such as production, physical properties, and so on.

Coal is the term that defines a brownish or black deposit, derived from ancient vegetation that was altered and accumulated from swamps or other environments that were very moist. As decomposition of the vegetation started and formed layers of peat, buried into land, the high pressure and temperatures turned the peat into coal.

By origin, the coal is divided into two types: one is called humic (derived from wood, plant remains) and sapropelic (derived from certain algae, spores or finely divided plant material).

The coal has a progressive transformation, because the proportion of carbon relative to the oxygen begins to rise and the volatile substances and water are driven out. There are six types of coal, that are very different to each other. The brown coal is soft, brown, with a high moisture content; subbituminous coal is the type of coal that is used in generating stations; bituminous coal is the most abundant type of coal; semibituminous coal; semianthracite coal has a fixed carbon content, that is between 86% and 92%; and anthracite coal, which is the type of coal with the highest procent of carbon, between 92% and 98%.

The deposits of coal were formed mostly in the Carboniferous and Permina periods. Recent coal formation occurred during the early Jurassic and Tertiary periods. The by-product of coal is coke.

Coke is a solid residue that contains carbon derived from low-ash, low-sulphur bituminous coal that is free of volatile constituents by baking in a oven at temperatures as high as 2000 F so that the carbon and residual ash are fusing together. Coke that is obtained from coal is grey, hard and porous.

Coke is used in several metallurgical and chemical processes that are requiring a source of carbon. Lower-grade cokes that are made by heating the coal to a lower temperature are used in domestic heating as smokeless fuels. 

Charcoal is the porous form of carbon that is produced by destructive distillation of organic material. The charcoal obtained from wood is used as a fuel. Just as coal, charcoal is different, depending on the source. Coconut shells that are the ingredients for charcoal are good gas absorbent. Animal charcoal is made by heating the animal bones and dissolving them in calcium phosphates and other mineral salts with acid. It is also used in the process of sugar refining. Activated charcoal is the charcoal that has been activated for adsorption by steaming or heating in a vacuum.