How does the feedstock react within the catalytic cracking riser reactor?

The reaction begins as the oil agents are mixed, and then they enter the main reaction zone in the middle and lower part of the lift pipe, where the majority of the reaction takes place. As the catalyst, onto which crude oil molecules are adsorbed, moves upward in the lift pipe, these molecular fragments into products such as gasoline, diesel, liquefied gas, dry gas, and coke. The production of dry gas and coke increases gradually, while the gasoline yield reaches its maximum at around 60% of the lift pipe’s height, after which it declines. As the reaction proceeds, the catalyst temperature decreases and its activity drops. The reactant molecules on the inner surface of the catalyst’s micropores undergo cracking reactions to form product molecules; after detaching from the inner surface of these micropores, the catalyst’s activity is partially restored. Inevitably, some coke is produced as a byproduct.