FCC process

Abstract

The present invention is a fluidized catalytic cracking process that incorporates a zoned riser reactor. The process provides an in-situ method for feed upgrading in a riser reactor. The process assists in the removal of undesirable contaminants, such as nitrogen, from FCC feedstocks.

1 . A catalytic cracking process comprising: 
 (a) passing a first portion of regenerated catalyst to a FCC reactor configured to have a plurality of zones;    (b) in a first upstream zone, contacting the first portion of regenerated catalyst with a secondary FCC feed, the secondary feed comprising steam and hydrocarbons boiling in the range of about 25° C. to about 250° C. wherein the residence time of the secondary feed in the first upstream zone is less than about 1.5 seconds;    (c) in a first primary feed conversion zone downstream from the first upstream zone, contacting the effluent from the first upstream zone with a primary FCC feed, wherein the effluent of the first upstream zone has sufficient enthalpy to vaporize at least 50 wt % of the FCC primary feed, the primary FCC feed comprising hydrocarbons boiling in the range of between about 250° C. and about 575° C., wherein the residence time within the first primary feed conversion zone is between about 0.2 and about 2 seconds and the catalyst to oil weight ratio is between about 2:1 and about 5:1;    (d) contacting a second portion of regenerated catalyst with a secondary FCC feed, the second portion of regenerated catalyst comprising a catalytic cracking catalyst, the secondary feed comprising steam and hydrocarbons boiling in the range of about 25° C. to about 250° C. and then passing the second portion of regenerated catalyst and partially converted secondary FCC feed to a second primary feed conversion zone positioned downstream from the first primary feed conversion zone; and,    (e) in the second primary feed conversion zone, contacting the effluent of the first primary feed conversion zone with the second portion of regenerated catalyst wherein the residence time within the second primary feed conversion zone is less than about 10 seconds.    
     
     
         2 . The process of    claim 1    wherein the secondary feed comprises light cat naphtha.  
     
     
         3 . The process of    claim 2    wherein the secondary feed further comprises between about 2 and about 50 wt % steam.  
     
     
         4 . The process of    claim 2    wherein the catalyst to secondary feed weight ratio in the first upstream zone is between about 30:1 and about 150:1.  
     
     
         5 . The process of    claim 1    wherein the residence time within the first upstream zone is between about 0.1 and about 1 seconds.  
     
     
         6 . The process of    claim 1    wherein the residence time within the first primary feed conversion zone is between about 0.2 and about 0.5 seconds.  
     
     
         7 . The process of    claim 6    wherein the residence time within the second primary feed conversion zone is less than about 2 seconds.  
     
     
         8 . The process of    claim 1    wherein the weight ratio of the first portion of catalyst to the second portion of catalyst is between about 1:1 and about 1:2.  
     
     
         9 . The process of    claim 1    wherein the effluent of the first upstream zone has sufficient enthalpy to vaporize at least 90 wt % of the FCC primary feed.  
     
     
         10 . A catalytic cracking process comprising: 
 (a) passing a first portion of regenerated catalyst to a FCC reactor configured to have a plurality of zones;    (b) in a first upstream zone, contacting the first portion of regenerated catalyst with a secondary FCC feed, the secondary feed comprising between 2 and 50 wt % steam based on the total weight of the secondary feed and light cat naphtha wherein the residence time of the secondary feed in the first upstream zone is less than about 1.5 seconds and wherein the catalyst to secondary feed weight ratio is between about 30:1 and about 150:1;    (c) in a first primary feed conversion zone downstream from the first upstream zone, contacting the effluent from the first upstream zone with a primary FCC feed, wherein the effluent of the first upstream zone has sufficient enthalpy to vaporize at least 50 wt % of the FCC primary feed, the primary FCC feed comprising hydrocarbons boiling in the range of between about 250° C. and about 575° C., wherein the residence time within the first primary feed conversion zone is between about 0.2 and about 0.5 seconds and the catalyst to oil weight ratio is between about 2:1 and about 5:1;    (d) contacting a second portion of regenerated catalyst with a secondary FCC feed, the second portion of regenerated catalyst comprising a catalytic cracking catalyst, the secondary feed comprising steam and hydrocarbons boiling in the range of about 25° C. to about 250° C. and then passing the second portion of regenerated catalyst and partially converted secondary FCC feed to a second primary feed conversion zone positioned downstream from the first primary feed conversion zone; and,    (e) in the second primary feed conversion zone, contacting the effluent of the first primary feed conversion zone with the second portion of regenerated catalyst wherein the residence time within the second primary feed conversion zone is less than about 2 seconds, wherein the ratio of the first portion of catalyst to the second portion of catalyst is between about 1:1 and about 1:2.    
     
     
         11 . A catalytic cracking process comprising: 
 (a) passing a first portion of regenerated catalyst to a FCC reactor configured to have a plurality of zones;    (b) in a first upstream zone, contacting the first portion of regenerated catalyst with a secondary FCC feed, the secondary feed comprising steam and hydrocarbons boiling in the range of about 25° C. to about 250° C. wherein the residence time of the secondary feed in the first upstream zone is less than about 1.5 seconds;    (c) in a first primary feed conversion zone downstream from the first upstream zone, contacting the effluent from the first upstream zone with a primary FCC feed, wherein the effluent of the first upstream zone has sufficient enthalpy to vaporize at least 50 wt % of the FCC primary feed, the primary FCC feed comprising hydrocarbons boiling in the range of between about 250° C. and about 575° C., wherein the residence time within the first conversion zone is between about 0.2 and about 2 seconds and the catalyst to oil weight ratio is between about 2:1 and about 5:1;    (d) in a second primary feed conversion zone downstream from the first primary feed conversion zone, contacting the effluent of the first primary feed conversion zone with a second portion of regenerated catalyst passed into the second conversion zone, the regenerated catalyst passed into the second conversion zone comprising a catalytic cracking catalyst wherein the residence time within the second primary feed conversion zone is less than about 10 seconds; and    (e) in a third primary feed conversion zone downstream from the second primary feed conversion zone, contacting the effluent of the second primary feed conversion zone with a third portion of regenerated catalyst passed into the third conversion zone, the regenerated catalyst comprising a catalytic cracking catalyst, wherein the residence time in the third primary feed conversion zone is between about 0.2 and 1 second.    
     
     
         12 . The process of    claim 11    wherein the secondary feed comprises light cat naphtha.  
     
     
         13 . The process of    claim 12    wherein the secondary feed farther comprises between about 2 and about 50 wt % steam.  
     
     
         14 . The process of    claim 13    wherein the catalyst to secondary feed weight ratio in the first upstream zone is between about 30:1 and about 150:1.  
     
     
         15 . The process of    claim 14    wherein the residence time within the first upstream zone is between about 0.1 and about 1 seconds.  
     
     
         16 . The process of    claim 11    wherein the residence time within the first primary feed conversion zone is between about 0.2 and about 0.5 seconds.  
     
     
         17 . The process of    claim 16    wherein the residence time within the second primary feed conversion zone is less than about 2 seconds.  
     
     
         18 . The process of    claim 13    wherein the weight ratio of the first portion of catalyst to the sum of the weights of the second and third portions of catalyst is between about 1:1 and about 1:2.  
     
     
         19 . The process of    claim 11    wherein the weight ratio of the second portion of catalyst to the third portion of catalyst is between about 1:2 and about 1:1.  
     
     
         20 . The process of    claim 11    wherein the effluent of the first upstream zone has sufficient enthalpy to vaporize at least 90 wt % of the FCC primary feed.  
     
     
         21 . The process of    claim 1    wherein the effluent of the first upstream zone has sufficient enthalpy to vaporize at least 80 wt % of the FCC primary feed.  
     
     
         22 . The process of    claim 11    wherein the effluent of the first upstream zone has sufficient enthalpy to vaporize at least 80 wt % of the FCC primary feed.  
     
     
         23 . A catalytic cracking process comprising: 
 (a) passing a first portion of regenerated catalyst to a FCC reactor configured to have a plurality of zones;    (b) in a first upstream zone, contacting the first portion of regenerated catalyst with a secondary FCC feed, the secondary feed comprising between about 2 and about 50 wt % steam based on the total weight of the secondary feed and light cat naphtha wherein the residence time of the secondary feed in the first upstream zone is less than about 1.5 seconds and wherein the catalyst to secondary feed weight ratio is between about 30:1 and about 150:1;    (c) in a first primary feed conversion zone downstream from the first upstream zone, contacting the effluent from the first upstream zone with a primary FCC feed, wherein the effluent of the first upstream zone has sufficient enthalpy to vaporize at least 50 wt % of the FCC primary feed, the primary FCC feed comprising hydrocarbons boiling in the range of between about 250° C. and about 575° C., wherein the residence time within the first conversion zone is between about 0.2 and about 2 seconds and the catalyst to oil weight ratio is between about 2:1 and about 5:1;    (d) in a second primary feed conversion zone downstream from the first primary feed conversion zone, contacting the effluent of the first primary feed conversion zone with a second portion of regenerated catalyst passed into the second conversion zone, the regenerated catalyst passed into the second conversion zone comprising a catalytic cracking catalyst wherein the residence time within the second primary feed conversion zone is less than about 10 seconds; and    (e) in a third primary feed conversion zone downstream from the second primary feed conversion zone, contacting the effluent of the second primary feed conversion zone with a third portion of regenerated catalyst passed into the third conversion zone, the regenerated catalyst comprising a catalytic cracking catalyst, wherein the residence time in the third primary feed conversion zone is between about 0.2 and 1 second 
 wherein the weight ratio of the first portion of catalyst to the sum of the weights of the second and third portions of catalyst is between about 1:1 and about 1:2, and wherein the weight ratio of the second portion of catalyst to the third portion of catalyst is between about 1:2 and about 1:1.