Week 9 – Jss 2 Third Term Basic Science Lesson Notes

WEEK9:
CRUDE OIL AND PETROCHEMICALS (1)
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The petroleum that comes out from oil production is a mixture of liquid, gaseous and solid hydrocarbon found naturally underground.
Hydrocarbons are compounds containing carbon and hydrogen only. Crude oil is the liquid form of the unrefined petroleum. It is a dark brown or greenish flammable liquid. It consists of a complex mixture of various hydrocarbons that differ in appearance, composition and purity. Crude oil also contains small particles of materials such as sulphur and metals. Other forms of petroleum are natural gas, which is stored in cylinders and used for cooking and bitumen used for tarring our roads.

PETRO CHEMICALS
These are chemical compounds which are derived from
The refining of petroleum. For example, methane is a refinery product which is used to produce carbon black and gas. Other examples of petro chemicals include;

1. Ethane and propene
2. Plastics such as polythene, synthetic fibres (nylon), rubber, etc
3. Detergent
4. Chemicals used for manufacturing of paints, medicine, insecticides, herbicides, nematicides, rodenticides, avicides etc.

   The process of deriving these petrochemicals involve the refining of crude oil, treatment of the crude fractions and finally production of the organic compounds that could from the bases of other industrial productions.
   REFINING OF CRUDE OIL
   Crude oil produced from rock is piped straight into oil storage tanks. From the storage tanks crude oil is transported to the refinery where it is separated into its components. Since crude oil is a mixture, a physical method of separation is used. This method is called fractional distillation.
   The fundamental process is the refining that separates crude oil into its components has different boiling points. The refining process therefore involves fractional distillation of crude oil into fractions, purification and conversion of the fractions into more useful products.
   The fractional distillation refining process involves the following steps:

   1. Heating the crude oil in gas furnace at a high temperature of 500°c to 600°c by passing it through heating pipes in the gas furnace.
   2. The vapour is passed into a tall fractionation tower, the temperature of which varies from 400°c at the top.
   3. Fractions of crude oil are collected from the different temperature levels in the trays of the tower. Each tray usually contains many bubble caps through which the vapors with similar boiling temperature pass and condense. The most volatile components are collected at the bottom of the tower.

   These fractions can be differentiated from one another by their different texture, color, odor, volatility and ease of ignition and burning. Nigeria has a lot of crude oil which is distilled in refineries to give us useful products which include:

   1. PETROLEUM GAS OR REFINERY GAS: this is obtained at the uppermost part of the tower. It is the product with the least boiling point.
      
   2. PETROL OR GASOLINE: this is the second product with relatively high temperature range and a number of carbon constituent than the refining gas.
      
   3. NAPHTHA: this has a high number of carbon atoms per molecules than petrol and it is usually further refined to give petrol.
      
   4. KEROSINE OR PARAFFIN OIL: it is a liquid with higher viscosity than bothj gasoline and naphtha.
      
   5. LIGHT GAS (DISEASL OIL OR GAS OIL): it is a very viscous product.
      
   6. HEAVY GAS OIL: it is more viscous than light gas, and it is usually colored.
      
   7. LUBRICATING OIL, FUEL OIL AND BITUMEN: they are usually referred to as residues; they are thick and non- volatile products.
      

      CRUDE OIL FRACTIONS AND ITS USES
      

 EVALUATION
1.Explain what crude oil and petrochemicals are.
2.Describe the process of refining crude oil.
3.Find the meaning of the following terms:

1. Crude oil exploration
2. Crude oil refining
3. cracking
4. List five by-products of refined crude oil.
   
5. What are the importance of petrol chemicals?