Patent ID: 8435401

Claim:
A method for cracking a hydrocarbonaceous feedstock, the method comprising the steps of: a) passing hot regenerated catalyst particles from a catalyst regenerator to the bottom portion of a first reactor and injecting a first portion of a hydrocarbon feed into the reactor with the catalyst particles; b) passing the catalyst particles and the first feed portion up through the first reactor and into a first stripping vessel, whereby the first feed portion is cracked and the catalyst particles are partially spent in the first reactor; c) separating the cracked first feed portion from the catalyst particles and delivering the cracked first feed portion into the first stripping vessel, wherein the separation is at least partially carried out by passing the catalyst particles through an active stripper including a plurality of active stripping structures; d) passing the catalyst particles from the first stripping vessel to the bottom portion of a second reactor and injecting a second portion of the hydrocarbon feed into the second reactor; e) passing the catalyst particles and second feed portion up through the second reactor and into a second stripping vessel whereby the second feed portion is cracked and the catalyst particles are further spent; f) separating the cracked second feed portion from the catalyst particles and discharging the cracked second feed portion into the second stripping vessel; and g) returning the catalyst particles to the regenerator and regenerating the catalyst particles.