Fractions of Crude oil

Petroleum gases – These gases are liberated at the top of the column at temperatures below 40o They are mainly hydrocarbons consisting of one of four carbon atoms per molecule, e.g methane, ethane, propane, butane and ethane. They are used mainly as fuels for homes and industries and for manufacture of products like hydrogen, sulphide and ethyne

Petroleum ethers and ligroin – This is the mixture of very volatile liquids consisting of hydrocarbons with five or seven carbon atoms per molecule. The petroleum ether or light petroleum distills over between 2oC to 60oC, while the ligroin or light naphtha distills over between 60oC to 100o

Petrol – Petrol or gasoline is a mixture of hydrocarbons consisting of four to twelve carbon atoms per molecule. It is a volatile liquid which distils over in the temperature range of 40oC to 200o Petrol is used as a fuel for aeroplanes and motor vehicles. It is a good solvent for paints and grease

Kerosene – Kerosene contains hydrocarbons with twelve to eighteen carbon atoms per molecule. It distils over in the temperature of 200oC to 250o it is a fairly volatile liquid and is used as a fuel for lighting and heating and for driving tractors and some modern jet engines. It is a good solvent for paint and grease

Gas oil and Diesel oil – They have twenty to twenty five carbon atoms per molecule. They distil over in the temperature of 250oC to 350o They are mainly used as fuel for heating and diesel engines and as raw materials of the cracking process

Lubricating oils – They are heavy oils. They consist of hydrocarbons with more than twenty five carbon atoms per molecule. They distill over in the temperature of 350oC to 500o They are viscous liquids used for lubricating moving parts of engines and machines. Grease belongs to this group. Vaseline and paraffin wax are solid long chain hydrocarbons which are obtained from re-distillation of heavy oils.

Bitumen and other residues – these are solid residues left behind at temperatures above 500o Bitumen are used for surfacing roads and airfields while other residues may be used as fuel, in protective paints and water proofing roofs.

Assessment (Post your answer using the Stoplearn.com box below for evaluation and discussion)

……… is the chief source of hydrocarbons

………. of petrol is a measure of the proportion of branched chain hydrocarbons in a given blend of gasoline (petrol).

……….. involves the separation of a mixture into a number of different parts, called fractions.

……….. is a sharp metallic sound produced in the internal combustion engine

Mention 4 fractions of crude oil