Catalytic cracking,

Definition of Catalytic cracking:

1. Petroleum refinery process in which heavy oil is passed through metal chambers (called catalytic crackers or cat crackers) under pressure and high temperature in the presence of catalysts such as alumina, silica, or zeolites. This boiling breaks up heavy, large, and more complex long-chain oil molecules into lighter, smaller, and simpler short-chain molecules such as those of gasoline.