Fluid catalytic cracking system and process

Abstract

One exemplary embodiment can be a fluid catalytic cracking system. Generally, the fluid catalytic cracking system includes a first reaction vessel and a second reaction vessel. The first reaction vessel may contain a first catalyst having pores with openings greater than about 0.7 nm and a second catalyst having pores with smaller openings than the first catalyst. What is more, the second reaction vessel may contain the second catalyst. Generally, at least a portion of the second catalyst is directly communicated with the first reaction vessel.

1 . A process for generating propylene in a system, comprising:
 A) communicating a first reaction vessel with a regeneration zone and a second reaction vessel wherein the first reaction vessel contains a first catalyst having pores with openings greater than about 0.7 nm and a second catalyst having pores with smaller openings than the first catalyst, and the second reaction vessel contains only the second catalyst for catalyzing at least one reaction.   
     
     
         2 . The process according to  claim 1 , wherein the second reaction vessel is at a temperature of about 550° to about 680° C. 
     
     
         3 . The process according to  claim 1 , further comprising communicating a spent second catalyst from the second reaction vessel to the first reaction vessel which, in turn, communicates the spent second catalyst with the regeneration zone.