Process and apparatus for upgrading FCC product with additional reactor with catalyst recycle

Abstract

A process and apparatus is disclosed for contacting feed with mixed catalyst in a secondary reactor that is incorporated into an FCC reactor. The mixed catalyst used in the secondary reactor is regenerated catalyst from a regenerator that regenerates spent catalyst from an FCC reactor that is mixed with spent catalyst from either the FCC reactor or the secondary reactor. The mixing of spent and regenerated catalyst reduces the catalyst temperature and tempers catalyst activity to inhibit both thermal and catalytic cracking reactions.

1 . An apparatus for cracking and further treating hydrocarbons, said apparatus comprising: 
 a fluidized catalytic cracking reactor comprising a first reactor vessel for contacting a first hydrocarbon stream with catalyst to yield cracked hydrocarbons and spent catalyst, a first separator vessel for separating said spent catalyst from said cracked hydrocarbons;    a secondary reactor comprising a second reactor vessel for contacting a second hydrocarbon stream with a mixture of regenerated catalyst and one of recycled spent catalyst and recycled spent mixed catalyst to yield upgraded hydrocarbons and spent mixed catalyst, said secondary reactor including a second separator vessel for separating said upgraded hydrocarbons from said spent mixed catalyst;    a recycle catalyst pipe in communication with said second reactor vessel, said recycle catalyst pipe for delivering one of said spent catalyst and said spent mixed catalyst to said second reactor vessel from one of said first separator vessel and said second separator vessel, respectively;    a first regenerated catalyst pipe communicating with said first reactor vessel for delivering regenerated catalyst to said first reactor vessel;    a second regenerated catalyst pipe in communication with said second reactor vessel for delivering regenerated catalyst to said second reactor;    a regenerator including an oxidizing gas distributor, said regenerator in communication with said regenerated catalyst pipe, said regenerator for receiving said spent catalyst to be contacted with said oxidizing gas from said oxidizing gas distributor to yield regenerated catalyst and flue gas, said regenerator including a separator for separating said regenerated catalyst from said flue gas; and    a spent catalyst pipe communicating said first separator vessel with said regenerator for delivering spent catalyst from said first separator to said regenerator.    
     
     
         2 . The apparatus of  claim 1  wherein said recycle catalyst pipe is in communication with said second separator vessel.  
     
     
         3 . The apparatus of  claim 1  wherein said second separator vessel includes a stripper section.  
     
     
         4 . The apparatus of  claim 1  wherein a spent mixed catalyst pipe communicates with said second separator vessel with said regenerator for delivering spent mixed catalyst to said regenerator.  
     
     
         5 . The apparatus of  claim 1  wherein a transport conduit communicates said second reactor vessel with said second separator vessel.  
     
     
         6 . The apparatus of  claim 5  wherein said riser conduit includes discharge openings at the end of swirl tubes.  
     
     
         7 . The apparatus of  claim 1  wherein said second separator vessel is in communication with an external cyclone.  
     
     
         8 . The apparatus of  claim 1  wherein said second reactor vessel includes a mixing pot in communication with said recycle catalyst pipe and said regenerated catalyst conduit.  
     
     
         9 . An apparatus for cracking and further treating hydrocarbons, said apparatus comprising: 
 a fluidized catalytic cracking reactor comprising a first reactor vessel for contacting a first hydrocarbon stream with catalyst to yield cracked hydrocarbons and spent catalyst, a first separator vessel for separating said first spent catalyst from said cracked hydrocarbons;    a secondary reactor comprising a second reactor vessel for contacting a second hydrocarbon stream with a mixture of recycled spent mixed catalyst and regenerated catalyst to yield upgraded hydrocarbons and spent mixed catalyst, said secondary reactor including a second separator vessel, said second separator vessel for separating said upgraded hydrocarbons from said spent mixed catalyst;    a recycle catalyst pipe in communication with said second reactor vessel, said recycle catalyst pipe for delivering said spent mixed catalyst to said second reactor vessel from said second separator vessel;    a first regenerated catalyst pipe in communication with said first reactor vessel for delivering regenerated catalyst to said first reactor;    a second regenerated catalyst pipe in communication with said second reactor vessel for delivering regenerated catalyst to said second reactor;    a regenerator including an oxidizing gas distributor, said regenerator in communication with said regenerated catalyst pipe, said regenerator for receiving said spent catalyst to be contacted with said oxidizing gas from said oxidizing gas distributor to yield regenerated catalyst and flue gas, said regenerator including a separator for separating said regenerated catalyst from said flue gas; and    a spent catalyst pipe in communication with said first separator vessel and said regenerator for delivering spent catalyst to said regenerator.    
     
     
         10 . The apparatus of  claim 9  further including a primary regenerated catalyst pipe for delivering regenerated catalyst to said first reactor vessel.  
     
     
         11 . The apparatus of  claim 9  wherein said second separator vessel includes a stripper section.  
     
     
         12 . The apparatus of  claim 9  wherein said spent mixed catalyst pipe includes a standpipe for delivering spent mixed catalyst to said regenerator.