Patent ID: 7316773
Filing Date: 2008-01-08
Classification: C10G

Abstract:
1. A catalytic cracking process, which comprises: 1) catalytic cracking a feedstock in a first riser for less than about 1.5 second and sending a resultant stream into a first separating device; 2) catalytic cracking a recycle oil obtained from the first separating device in a second riser for less than about 1.5 second and sending a resultant stream into the first separating device; and 3) carrying out catalytic reaction of a crude gasoline stream and/or optionally a diesel oil stream obtained from the first separating device in a descending third riser; wherein the reaction conditions and the catalysts used in the first to third risers are selected according to the requirement for the product of the catalytic cracking process, and the catalyst regeneration and recycle systems are formed respectively for the catalysts used in the first to third risers, wherein a high temperature catalyst coming from a first regenerator ( said oil-vapor enters the first separating device, said first separating device being a fractionation tower ( said oil-vapor coming from the top of the fractionation tower ( wherein oil-vapor coming from the top of the second settler enters a stripping tower (