One exemplary embodiment can be a fluid catalytic cracking system. The fluid catalytic cracking system can include a reaction zone including a riser having a top and a bottom adapted to receive spent catalyst at a first elevation and regenerated catalyst at a second elevation. Typically, the first elevation is lower than the second elevation. Additionally, the fluid catalytic cracking system can include a gas distributor contained near the bottom of the riser in communication with a hydrocarbon feed.