A presentation on Petroleum for the
Course: B.Tech. Polymer Science in DU FYUP
Subject: Raw Materials,
Year - For Ist Year Students.
You may download this ppt to get a better idea about the contents and animation!
2. INDEX
Petroleum
Petrochemicals
Origin of petroleum
Carbide theory
Engler Theory
Modern Theory
Occurrence of petroleum
Refining of petroleum
Cracking
Thermal Cracking
Catalytic Cracking
End Credits
3. PETROLEUM
Petroleum is a dark coloured viscous oil found in deep Earth crust. Chemically it is a mixture of various types of
hydrocarbons along with oxygen, nitrogen and sulphur containing compounds. The average composition of
petroleum is :
C = 80 -85%
H = 10 -14%
S = 0.1- 0.5%
N & O = Negligible.
Liquid Oil
Mineral Oil (Petroleum)
Organic Oil
4. PETROCHEMICALS
Petrochemicals are the chemicals which are made from raw materials dried from petroleum and its fractions. They
are known as petrochemicals.
Alkanes, alkenes, cycloalkanes, benzene and its homologues are dried from petroleum and its fractions.
These are used as raw materials for the manufacturing of industrially important chemicals like phenol, ammonia,
ethanol, vinyl monomers, styrene, acetic acid, acetone etc. and these find extensive used for the preparation of
explosives, drugs, paints, adhesives, rubbers, insecticides etc.
Haldia Petrochemicals Ltd., often referred to as HPL, is the second
largest petrochemical company in India, with the company claiming
a total capacity equivalent to 7, 00,00.0 TPA of ethylene.
6. CARBIDE THEORY
According to this theory, hydrocarbons present in the petroleum are formed by the action of water and inorganic
chemicals.
Ca + 2C CaC2
CaC2 + H2O Ca(OH)2 + C2H2
4Al + 3C Al4C3
Al4C3 + 12H2O 4Al(OH)3 + 3CH4
Disadvantages
It fails to explain
The presence of optically active compounds.
The presence of nitrogen and sulphur compounds.
The presence of chlorophyll and haemine.
7. ENGLER THEORY
According to this theory, petroleum is of animal origin. He suggested that petroleum is formed by the decay and
decomposition of animals under high pressure and temperature.
He suggested the following facts:
Experiment the destructive distillation of fish oil and other animal fats under high pressure and temperature give a
similar product to the natural petroleum.
Presence of brine or sea water together with petroleum.
Presence of optically active compounds, nitrogen and sulphur compounds and fossils in the petroleum area.
Disadvantages
It fails to explain the presence of chlorophyll, coal deposits in the vicinity of oil fields.
8. MODERN THEORY
According to this theory petroleum is believed to be formed by the decay and decomposition of marine chemicals
as well as that of vegetable, organisms or simply it is of animal as well as plant origin.
This theory explains all the facts which were the drawbacks of previous theories.
9. OCCURRENCE OF PETROLEUM
It is oftenly associated with natural gas which exerts pressure on the
the oil surface and drives it out with great velocity through natural
openings.
America is the biggest oil producing country of the world followed
by
Russia
Venezuela
Mexico
Romania
Iraq
Burma
Pakistan
India – In India, it is found in Bombay High, Assam, Gujarat and
some parts of Bihar.
12. CRACKING
It may be defined as the process of decomposition of higher molecular weight hydrocarbons having higher boiling
point to lower molecular weight hydrocarbons having lower boiling point.
Process of cracking involves following chemical changes:
Higher hydrocarbons are converted to lower hydrocarbons by C-C cleavage.
Straight chain alkanes are converted into branched chain alkanes.
Saturated hydrocarbons are converted into unsaturated hydrocarbons.
Cyclisation of aliphatic alkanes takes place.
13. THERMAL CRACKING
When cracking is done in the presence of heat and pressure it is known as thermal cracking.
Liquid Phase thermal Cracking
In this process, residual oil is cracked at 470- 575o C at 7 – 10 atmospheric pressure. The cracked products are
separated in a fractionating column. 3 important fractions are obtained in the following percentages:
Cracked gasoline : 30 -35%
Cracked gas : 10 – 15%
Cracked residue : 50 – 55%
Vapour phase thermal cracking
In this petroleum fractions of low boiling range like kerosene oil are heated at a temperature of 670- 720oCat a
small atmospheric pressure. In this yield of gasoline is good and anti – knock factors are better than octane number.
(Octane no. is less than 70)
14. CATALYTIC CRACKING
In this cracking is done in the presence of a catalyst usually a mixture of silica and alumina. It requires much lower
pressure and temperature than thermal cracking.
Fixed Bed catalytic Cracking
The heavy oil charge is passed through pre – heater where it is heated to 425- 450oC which h is passed over a fixed
bed of catalyst chamber maintained at fixed temperature and 1.5 kgcm-2 pressure. During their passage through the
tower about 40% of the charge is converted into gasoline and about 2- 4 %carbon is formed. This carbon black is
adsorbed by the catalyst belt and after 8- 10 hours the catalyst stops functioning due to the deposition of black layer
of carbon which is later burned and the catalyst is activated. The vapours are then passed through the cooler where
the gasoline condenses with some other gases. It is then sent to a stabilizer where the dissolved gases are removed
and pure gasoline is recovered.
Moving Bed Catalytic Cracking
In this feed oil is first passed through the heater the pre heated oil vapours along with powder catalyst are then
passed to a reactor which is maintained at 500oC temperature for catalytic cracking. Cyclone allows only cracked
oil vapours to pass on to the fractionating column but retain the catalyst powder which becomes heavier due to
coating with carbon where it is forced by air blast to the regenerator. In this carbon is burned and regenerated
catalyst then flows through stand pipes for fixing fresh batch of feed oil.