1. The Oil Industry

2. Importance of oil as a chemical feedstock
Crude oil is a mixture of many different hydrocarbons which was produced from the decay of marine organism millions years ago. It’s often found together with natural gas. It is mainly used as fuel to supply the world’s energy demands. 10% of oil used after refining, as chemical feedstock, such as plastics, pesticides, food addictives, detergents, cosmetics and solvents

3. Fractional distillation of oil
Crude oil is heated to about 450oC and vaporized hydrocarbons move up a fractionating column. Superheated steam is added to maintain the temperature and ensure the vapor moves up through the column. Bubble caps in column allow the hot rising vapor to pass through the liquid that has condensed at each level. At each level the condensed higher boiling point components are tapped off or re routed to lower level

4. Removal of sulfur
Crude oil contain sulfur mainly in the form of hydrogen sulfur from anacrobic decay of sulfur
This must be removed before the oil can be refined as it can poison catalyst by blocking their active sites and it’s also removed to prevent acid rain

5. cracking
The process conducted at high temperatures. Large hydrocarbons are broken into smaller and more useful molecules. Main products are alkanes, alkenes:
C10H22(g) -> C8H8(g) + C2H4(g)

6. Steam cracking
The feedstock is preheated, vaporized, and mixed with steam and then converted to low molecular mass alkenes at 1000 – 1150K

7. Catalytic cracking
The use of alumina catalyst enables the cracking to take place at the relatively lower temperature of about 750K

8. The composition and characteristic of crude oil fractions
Carbon chain length
Boiling range/oC
Main uses
Refinery
1 -4
<30
Used as fuel on site gaseous cooking fuel and as feedsctock for chemicals, e.g: methane is used to provide hydrogen gas gor the Haber process
Gasoline and naphtha
5-10
40 – 180
Gasoline (petrol) for cars. Feedstock for organic chemicals (by steam cracking)
Kerosine
11-12
Fuel for jet engine; domestic heating; cracking to provide extra gasoline
Gas oil (diesel oil)
13 – 25
220 – 350
Diesel engines and industrial heating; cracked to produce extra gasoline
Residue
>20
>350
Fuel for large furnaces; vacuum distilled to make lubricating oils and waxes. Residue of bitumen and asphalt used to surface roads and waterproof roofs