Catalytic cracking of petroleum

1. Bangabandhu Sheikh Mujibur Rahman
Science & Technology University
Tohmina Khatun Abdul Khaleque
ID:20140107021 Lecturer
Dept. of ACCE Dept. of ACCE
BSMRSTU BSMRSTU
Topic
Catalytic cracking of petroleum

2. Petroleum
 Petroleum or crude oil is a complex, naturally
occurring liquid mixture containing mostly
hydrocarbons, but containing also some compounds
of oxygen, nitrogen and sulfur.
 It is often referred to as the “black gold.”

3. Cracking of Petroleum
Cracking:
Cracking is a process of breaking down the large hydrocarbon
molecules into smaller ones. Cracking is also called pyrolysis.

4. Classification of cracking
Cracking may be carried out by three different processes viz.
(1) Thermal cracking
(2) Catalytic cracking
(3) Hydrogenation cracking

5. Thermal cracking
• Thermal cracking :
Thermal cracking is a process by which large
hydrocarbon molecules are thermally decomposed under
pressure.

6. Catalytic cracking of petroleum
Catalytic cracking is process by which large hydrocarbon
molecules are decomposed in presence of catalyst, under
pressure and temperature.
It serves to improve
(a) Rate of reaction
(b) Antiknock quality of gasoline
(c) Octane number
(d) Flexibility

7. Catalyst
Many substances can act as conversion catalyst but in general
the following are used:
(i) Natural clays;
(ii) Synthetic materials e.g.
(a) Alumina and silica

8. catalysts continue
The catalysts are used either as pellets or as a fine powder.
It serves to improve
(a) Rate of reaction
(b) Antiknock quality of gasoline
(c) Octane number
(d) Flexibility

9. Operation conditions of catalytic
cracking
(1) Temperature – 750-1000oF
(2) Pressure - atmosphere to 100 psi
(3) Catalyst to oil ratio = 0.2 to 20 by weight in continuous
catalytic cracking unit

10. Classification of catalytic cracking
process
Based on the techniques of catalyst handling catalytic cracking
process are of four types:
(1) Fixed bed catalytic cracking
(2) Moving bed catalytic cracking
(3) Fluidized bed catalytic cracking
(4) Once-through catalytic cracking

11. Advantages of catalytic cracking
(1) Gasoline of high octane number can be produced
(2) Cost of the product is comparatively low.
(3)Equipment operates under low pressure.