In South Africa, where hard coal - mineral coal - is plentiful, it began to be converted into oil a few years ago.
Large quantities of coal are exposed to fire and for several minutes it is ground with a mixture of steam and oxygen at high pressure. This material burns and releases large amounts of carbon-rich gas and hydrogen, the basic constituents of oil.
Since coal contains only half as many hydrogen atoms as oil, it is necessary to add such an element to coal by means of water vapour. When coal burns, it generates enough energy to separate the molecules of steam into hydrogen and oxygen atoms. This achieves a balance between the two.
This resulting gas is "washed" with methanol to remove cyanide and sulfur. Then it goes to reactors in which, according to the chemical treatment applied, a certain final product is obtained. The reactors can produce oil, gasoline, liquefied gas, waxes and compounds such as aldehydes, acetones and alcohols. However, the process is costly.
