Chapter 15 - Lecture 2 – Cracking of Hydrocarbons

Cracking:

Cracking is the process by which;

1. the heavier,
2. lesser in demand,
3. long chains of hydrocarbons

are broken down into;

1.  lighter,
2. more in demanded,
3. smaller chains of hydrocarbons
4. more useful

fractions.

Example:

There are 2 types of cracking:

1. Thermal cracking
2. Catalytic cracking

Thermal cracking:

In thermal cracking, heat in the absence of Oxygen, is used to break long chains of hydrocarbons to smaller ones. This process requires a temperature of 450°C and pressure up to 60 atm.

Catalytic Cracking:

In catalytic cracking, a catalyst, usually aluminium or porous rocks under low pressures and 500°C temperature, and absence of oxygen, is used to break long hydrocarbons to smaller ones.

Naphtha:

The naphtha fraction of crude oil is obtained in abundance from crude oil. It does not have any direct industrial use. It is therefore, becomes the source of many hydrocarbons. The lighter fractions obtained by cracking naphtha have a wide variety of industrial usage.

                                                                                       ©Tanzeela Zafar Siddiqui