Petroleum Products and Their Uses

Since petroleum is a mixture of hydrocarbons with different molecular weights and boiling points, distillation separates it into different fractions. These yield petrol, which contains hydrocarbons that boil in the 40-200 degrees C range and have from 5 to 11 carbon atoms in their molecules; naphtha, which contains hydrocarbons with a greater number of carbon atoms and boiling points ranging from 120 to 400 degrees C; kerosene, which boils from 150 to 310 degrees C, and gas oil. These are the so-called light oils. When these oil products have been distilled off, there remains a viscous black liquid called residual oil.

Petrol is used as fuel for internal combustion engines; the principal two grades are aviation petrol and motor fuel, which are used for aircraft and motor cars respectively. Aviation petrol boils within the 40-180 degrees C range; motor fuel, within the 50-200 degrees C range. Petrol is also used as a solvent for oils and rubber, to remove greasy stains from fabrics, etc. Kerosene is used as fuel for tractors, jet aircraft, and rockets; in the absence of electricity it is used for lighting. Gas oil serves as fuel for diesel engines.

The additional distillation of residual oil yields various lubricants. These differ in properties (for instance, have a different viscosity) depending upon the hydrocarbons they contain. Accordingly, they are used to lubricate different engines, devices, and mechanisms. Lubricants are thus divided into automobile oil, aircraft oil, diesel lubricating oil, industrial lubricant, etc.

After the lubricants have been distilled off from the residual oil there remains a non-volatile dark mass called oil tar, which is used as a road binder.

Besides being refined into lubricants, residual oil is subjected to chemical processing to produce petrol and is used as a liquid furnace fuel.

From some grades of petroleum it is also possible to prepare a mixture of solid hydrocarbons, which is known as paraffin wax. This is used to make candles, to impregnate paper in order to make it water-proof, and in medicine. There is also a mixture of liquid and solid hydrocarbons that is known as vaseline. Commercial vaseline is used to grease metal goods in order to protect them from corrosion; purified vaseline is used in medicine as a base for ointments.

16. Ответьте на следующие вопросы:

1. What is petroleum? 2. What does the process of distillation yield? 3. What is the boiling point of kerosene? 4. What is called “residual oil”? 5. In what branches of industry is petrol used as fuel? 6. What can you say about the using of kerosene and gas oil? 7. What does the additional distillation of residual oil yield? 8. What kinds of lubricants do you know? 9. What is meant by oil tar? Where is it used?
10. What is known as “paraffin wax”? Where is it used? 11. What can you say about commercial vaseline? 12. What are the main petroleum products?