Crude Oil
Crude oil is a naturally occurring unrefined oil existing as hydrocarbon. It can be refined to produce a wide range of energy producing petoleum products.
Often referred to as “black gold,” crude oil consists of hydrocarbons that can be refined to produce energy producing products such as; petrol, dieselene, lubricating oil, kerosene, gas and other useful petrochemicals. The by-products of the refining process include such things as coke, waxes, tar, asphalt and starting materials that are used to make other products.
Crude Oil is Found in Buried Ancient Sea Beds
Not all crude oil is black as its colour can range from black to yellow and many shades in between. Its colour depends on its hydrocarbon composition. Different crude oils also have varying viscosity levels, some crude oils can be as fluid as water whereas others can be that thick they are close to being solid. Crude oil is what is known as a fossil fuel, this means it has evolved naturally from decaying plants and animals that once lived in an ancient sea many millions of years ago. Most places where crude oil is found were once sea beds.
Hydrocarbon Molecules of Crude Oil Make it an Important Substance
The secret behind crude oil being so useful is that it can be the starting point for many substances because of its hydrocarbon content. Hydrocarbons are molecules that exist of carbon and hydrogen that come in various structures and lengths . They can be in the form of straight chains to branching chains and rings. The two main reasons why hydrocarbons are so important are that:
1. They contain a lot of energy when refined into products such as petrol, diesel, paraffin wax etc.
2. They can exist in many forms, for instance, the smallest hydrocarbon is methane gas which is lighter than air. Longer chains exist as liquids and very long chains are solids, such as tar or wax. When these hydrocarbon chains are cross linked it is possible to make them into products such as nylon, synthetic rubber, tupperware plastic etc.
Crude Oil has to be Refined to Make it Useful
To make crude oil useful you have to separate the many different hydrocarbons that are all mixed together. This is achieved by refining, with the first stage being distillation, a process whereby the crude oil is heated and the different molecules separated as different components.
The different hydrocarbon molecule chain lengths have progressively higher boiling points. This means they can be separated by distillation with the different chain lengths pulled out as they reach their differing vaporisation temperatures. Each different chain length has its own individual property that makes it useful in a different way to another.
Refining of crude oil separates the different molecule chain lengths that results in the separation of the following products:
Petroleum gas
that is used for cooking, heating and making plastics. Petroleum gas is known as methane, butane or propane. It liquifies under pressure to form liquid petroleum gas (LPG) Liquid petrol
Liquid kerosene
, a jet engine fuel and a fuel for certain tractors as well as lighting and heating Dieselene distillate
that is used as diesel fuel and heating oil, as well as being a starting material in the manufacturing of other products
Lubricating oil
such as motor oil, grease etc.
Heavy fuel oil
which is an industrial fuel and also used as a starting material in the manufacturing of other products
Residuals
, a starting product in the making of other products as well as being useful in the form of waxes, tar, asphalt and coke.
