Tag: rocks and minerals

Most of the carbon structures in the organic part of the coal are “alkylaromatics”, that is aromatic cores with aliphatic appendages like benzene, naphthelene and anthracene.
coal is heated in several different processes, all of which produce gases, liquids, asphaltic solids, and crude carbon charcoal. These are processed furthur to give several industrial products, invariably consisting of inseparable mixtures of organic compounds.

Napthalene balls used to repel moth and other insects are also obtained from coal tar. These days Bitumen, a petroleum product is used in place of coal tar for metalling roads. The gases present in coal gas are combustible.

When substances of vegetable origin, e.g. coal, oil shale, peat or wood, are heated in the absence of air (dry distillation), they decompose into gas, liquid products and solid residue coke/charcoal.

Coal tar is the destructive distillation of bituminous coal. Coal tar is distilled into many fractions to yield a number of useful organic products like benzene, toluene, xylene, naphthalene, anthracene, etc.

Generally coal mine and coal gas contain Carbon monoxide, carbon dioxide, methane, oxygen, nitrogen, hydrogen, and other hydrocarbons.

Coke can be used both as a fuel and a reducing agent. The combustion of coke (carbon) is highly exothermic and releases a huge amount of energy. Hence, coke is a fuel. Carbon itself is easily oxidized to $CO$ and $CO _2$. $C$ can easily reduce several metal oxides to metal.

Syngas or synthesis gas is a fuel gas mixture consisting primarily of H, CO and very small carbon dioxide. The reaction between coke and steam is highly endothermic and when the coke bed is cooled to a normal temperature the steam is replaced by a blast of air.

Coal tars are complex and variable mixtures of phenols, polycyclic aromatic hydrocarbons (PAHs), and heterocyclic compounds. Hence have unpleasant smell.

Coking is the process used industrially to produce coke. They produce many compounds which are very useful industrially.

Synthesis gas is made by passing steam over a red-hot carbon fuel such as coke, Water gas is a mixture of carbon monoxide and hydrogen produced from synthesis gas
$ H _2O + C\rightarrow  CO + H _2(\delta H = +131KJ/mol)$
Synthesis gas is a useful product, but requires careful handling due to its flammability and the risk of carbon monoxide poisoning.