Crude Oil Research Paper

1 PETROLEUM

Petroleum is a mixture of gaseous, liquid and solid hydrocarbon that occurs naturally beneath the earth's surface (Awake, 2003). Petroleum is composed of hydrocarbons (hydrogen and carbon) and may exists as crude oil, natural gas or condensates. Crude oil is a naturally occurring, free flowing liquid mainly hydrocarbons with its specific gravity between 1.00 and 0.80. The major elements of crude oil are carbon (83-87%) and hydrogen (10-14%) and minor elements, nitrogen (s density is an important measure of its overall quality. Oil density is sometimes expressed in terms of its specific gravity but more often is given as API gravity. The American Petroleum Institute (API) has developed a special measure that expressed oil density

The equation above implies that high specific gravity crude oils have low API gravity and vice versa.

Crude oil is classified as light, medium, heavy and extra heavy, according to its measured API gravity. Light Crude has an API gravity greater than 31.1 ̊API, medium crude oil has an API gravity between 22.3 ̊API and 31.1 ̊API, heavy Crude oil has an ̊API Gravity between 10 ̊API and 22.3 ̊ API and extra heavy crude oil has less than 10 ̊API (Martinez, 1984). Light and medium crude oils are found in Nigeria and the crude source area joined with the API gravity is used to determine the peculiar designated area like Bonny medium, forcados blend (Osuji, 2002) .

2.2.2 COLOUR

Colour is another physical characteristics of crude oil, crude oil may be black, brown, yellow or may have a shade of these colour (Hunt, 1996; Achugasim, 2002).

Other properties of crude oil are viscosity and conductivity.

2.2.3 SULPHUR CONTENT

The amount of sulphur is an important factor in the handling of crude oil. Crude oil can be classified as sweet or sour depending on its sulphur content. Crude oil containing less than 0.5% sulphur is classified as sweet while those with greater than 0. 5% sulphur are termed

2.3 CHEMICAL COMPOSITION OF CRUDE OIL

The most abundant chemical compounds of petroleum are hydrocarbons which give the petroleum composition its combustible nature. Although the composition of petroleum will contain many trace elements, the key compounds are carbon (93% – 97%), hydrogen (10% - 14%), nitrogen (0.1% - 2%), oxygen (0.1% - 1.5%) and sulphur (0.5% - 6%) with a few trace metals making up a very small percentage of the petroleum composition (Hunt, 1996).

2.4 CLASSIFICATION OF HYDROCARBON

The properties of hydrocarbons are classified in terms of its hydrocarbon structure.

2.4.1 ALKANES (PARAFFINS)

Alkanes form the basis of petroleum fuels and can be in linear and branched forms. Alkanes are referred to as saturated hydrocarbons which means they only contain single bond between all carbon atoms (MuMurry, 1992). The wax present in petroleum primarily consists of paraffin and naphthenic hydrocarbons. Depending on their temperature and pressure, hydrocarbon components of wax can exist can gas, liquid or solid (Syukri et al.,