FCC reactor vessel

Fluidized catalytic cracking reactor vessel comprising at its upper end means to separate catalyst particles from an effluent of a dilute phase fluidized catalytic cracking reactor riser, which separation means are fluidly connected to the downstream part of the reactor riser, fluidly connected with means to discharge the cleaned reactor riser effluent from the vessel and fluidly connected to means to discharge the separated catalyst to the lower end of the vessel, the vessel further comprising at its lower end means to discharge catalyst from the reactor vessel, wherein (a) between the side wall of the vessel and the separation means a shield is present, resulting in an exterior space between the vessel wall and the shield and an interior space within the shield, wherein the interior space is in open communication with the lower end of the reactor vessel at its lower end and wherein the exterior space and interior space are fluidly connected by means of one or more openings, and (b) means are present to supply a gas poor in coke precursors to the exterior space.