- Crude oil is a fossil fuel formed deep down in the ground from the remains of plants and animals from ancient times. It is also referred to as petroleum. It comprises of a mixture of several hydrocarbons. Hydrocarbons are molecules containing carbon and hydrogen (C-H) bonds.

In crude oil, the hydrocarbon molecules are of different sizes. Some are very small (having small chain lengths) while others are large with very many C-H chains. The smallest hydrocarbon in crude oil is methane - CH4, which is a very light gas, much lighter than air.

Other smaller hydrocarbons are BTEX - Bezene, Toluene, Ethylbenzene, and xylenes. These substances are volatile and possess low boiling points of around 40 - 85 C.

To make the components of crude oil useful, they have to be separated into their respective fractions by a procedure called fractional distillation. This is achieved in a distillation column similar to the one shown below. The small chains, usually gaseous molecules come out at the top while the liquid medium chain molecules come out at the middle and the solid remains at the bottom.

Crude oil prospecting is done to establish locations that have crude oil stored underground. The crude oil is then pumped out from the ground through the system of wells and pipes to the distillation station where the crude oil is separated into various components.

Crude oil fractions include: - Naptha, gasoline, kerosines, gas oil or diesel, lubricating oil, and heavy gas oil etc.

These substances, undoubtedly, have been the drivers of the World's economy for centuries. In other words, crude oil have been an important resource to humanity. However, because it produces pollution like other fossil fuels and the fact that it is non-renewable, it is necessary to find other energy source replacement.

Crude Oil is burned at a power station just like coal to generate heat to generate the steam that drives a turbine connected to the generator that generate electricity.

Fuel Oil is burnt in the power plant to release heat and produce steam which is used to power a turbine attached to an electrical generator system to provide electricity. 

Besides use in firing power plants, other components of crude oil such as gasoline and diesel has been used to run cars and produce heat for domestic and industrial needs.

Like other fossil fuels, crude oil releases pollution, mainly CO2 which is one of the greenhouse gases scientists have said cause global warning. Consequently alternative/renewable energy sources are being advocated to replace crude oil components. For instance, car manufacturers are now manufacturing cars that will use ethanol or ethanol/gasoline blended (gasohol) instead of gasoline, while biodiesel is replacing diesel to run diesel fuelled vehicles and engines. The push for these alternative energy sources are getting stronger by the day with substantial research funding into the manufacturing of the alternatives to oil.

Increasingly rising prices of crude oil prices and hence pump prices (or petroleum retail prices) of gasoline and other refined petroleum are also driving the need to develop alternative/renewable energy systems.

Related Sites:

• Oil-producing countries (Wikipedia)
• OPEC (website)