Synthetic zeolites are widely used as catalysts in the petrochemical industry, for instance in fluid catalytic cracking and hydro-cracking. Zeolites confine molecules in small spaces, which causes changes in their structure and reactivity. The hydrogen form of zeolites (prepared by ion-exchange) are powerful solid-state acids, and can facilitate a host of acid-catalyzed reactions, such as isomerisation, alkylation, and cracking. The specific activation modality of most zeolitic catalysts used in petrochemical applications involves quantum-chemical Lewis acid site reactions.
Catalytic cracking uses a furnace and reactor. First, crude oil distillation fractions are heated in the furnace and passed to the reactor. In the reactor, the crude meets with a catalyst such as zeolite. It goes through this step three times, each time getting cooler. Finally, it reaches a step known as separator. The separator collects recycled hydrogen. Then it goes through a fractionator and becomes the final item.