Thermal Cracking - continued.

There are two basic types of cracking processes:

a. Use heat to break the larger molecules (thermal cracking)

b. Use catalysts to change the molecular structure of hydrocarbons (catalytic cracking)

Here we are dealing with thermal cracking processes. The thermal cracking process was developed around 1913. Distillate fuels and heavy oils were heated under pressure in large drums until they cracked into smaller molecules which had better antiknock characteristics. However, this method produced large amounts of solid, unwanted coke. This early process has evolved into the following applications of thermal cracking: visbreaking, steam cracking, and coking.