Hydroprocessing of high density cracked fractions

Abstract

Systems and methods are provided for upgrading a high density cracked feedstock, such as a catalytic slurry oil, by hydroprocessing. The upgrading can further include performing a separation on the effluent from hydroprocessing of the cracked feedstock, such as a distillation (i.e., separation based on boiling point) or a solvent-based separation. The separation on the hydroprocessed effluent can allow for separation of an aromatics-enriched fraction and an aromatics-depleted fraction from the hydroprocessed effluent. The aromatics-enriched fraction and aromatics-depleted fraction can then be separately used and/or separately undergo further processing.

1 . A method for processing a heavy cracked feedstock, comprising:
 exposing a feedstock comprising a density at 15° C. of 1.06 g/cm 3  or more and at least 50 wt % of one or more 343° C.+ cracked fractions to a hydroprocessing catalyst under fixed bed hydroprocessing conditions to form a hydroprocessed effluent, the one or more 343° C.+ cracked fractions having an aromatics content of 40 wt % or more relative to a weight of the one or more 343° C.+ cracked fractions, a 343° C.+ portion of the hydroprocessed effluent having a density at 15° C. of 1.04 g/cm 3  or less;   separating the hydroprocessed effluent in one or more separation stages to form an aromatics-enriched fraction and an aromatics-depleted fraction; and   exposing at least a portion of the aromatics-enriched fraction to a second hydroprocessing catalyst under second fixed bed hydroprocessing conditions to form a second hydroprocessed effluent.   
     
     
         2 . The method of  claim 1 , wherein exposing the feedstock to the hydroprocessing catalyst further comprises exposing the at least a portion of the aromatics-enriched fraction to the hydroprocessing catalyst, wherein the hydroprocessing conditions comprise the second hydroprocessing conditions, and wherein the hydroprocessed effluent comprises the second hydroprocessed effluent. 
     
     
         3 . The method of  claim 1 , wherein the separating the hydroprocessed effluent in one or more separation stages comprises performing a separation based on boiling point to form an aromatics-enriched fraction and an aromatics-depleted fraction. 
     
     
         4 . The method of  claim 3 , wherein the aromatics-enriched fraction has a T10 distillation point of 371° C. or more, and the aromatics-depleted fraction has a T90 distillation point of 371° C. or less. 
     
     
         5 . The method of  claim 3 , wherein the aromatics-enriched fraction has a T10 distillation point of 454° C. or more, and the aromatics-depleted fraction has a T90 distillation point of 454° C. or less. 
     
     
         6 . The method of  claim 1 , wherein the separating the hydroprocessed effluent in one or more separation stages comprises performing a solvent-based separation to form an aromatics-enriched fraction and an aromatics-depleted fraction. 
     
     
         7 . The method of  claim 6 , wherein the separating the hydroprocessed effluent in one or more separation stages further comprises performing a separation based on boiling point prior to performing the solvent-based separation to form the aromatics-enriched fraction and the aromatics-depleted fraction. 
     
     
         8 . The method of  claim 6 , wherein the solvent-based separation comprises solvent extraction using an aromatic solvent, the aromatic solvent optionally comprising N-methylpyrrolidone. 
     
     
         9 . The method of  claim 1 , the method further comprising exposing at least a portion of the aromatics-depleted fraction to a distillate hydroprocessing catalyst under distillate fixed bed hydroprocessing conditions to form a distillate hydroprocessing effluent. 
     
     
         10 . The method of  claim 1 , wherein the one or more 343° C.+ cracked fractions comprise a coker bottoms fraction, a steam cracker tar fraction, a coal tar, a visbreaker gas oil, or a combination thereof. 
     
     
         11 . The method of  claim 1 , wherein the one or more 343° C.+ cracked fractions comprise a catalytic slurry oil, or wherein the one or more 343° C.+ cracked fractions consist essentially of a catalytic slurry oil. 
     
     
         12 . The method of  claim 11 , further comprising settling the catalytic slurry oil prior to exposing the feed to the hydroprocessing catalyst, the settled catalytic slurry oil having a catalyst fines content of 1 wppm or less. 
     
     
         13 . The method of  claim 1 , wherein the feedstock comprises at least 60 wt % of the one or more cracked feeds. 
     
     
         14 . The method of  claim 1 , wherein the one or more 343° C.+ cracked fractions comprise about 2 wt % or more n-heptane insolubles and the hydroprocessed effluent comprises about 1 wt % or less n-heptane insolubles; or wherein the one or more 343° C.+ cracked fractions comprise at least a first amount of micro carbon residue, and the hydroprocessed effluent comprises less than about half of the first amount of micro carbon residue; or a combination thereof. 
     
     
         15 . The method of  claim 1 , wherein the one or more 343° C.+ cracked fractions comprise at least 3 wt % of a 566° C.+ portion, the effective hydroprocessing conditions being effective for 55 wt % or more conversion of the feedstock relative to 566° C. 
     
     
         16 . The method of  claim 1 , wherein the feedstock comprises 4.0 wt % or more of micro carbon residue; or wherein the hydroprocessed effluent comprises 4.0 wt % or less of micro carbon residue; or a combination thereof. 
     
     
         17 . The method of  claim 1 , wherein the feedstock comprises at least 1.0 wt % of organic sulfur, the hydroprocessed effluent comprising 1000 wppm or less of organic sulfur. 
     
     
         18 . The method of  claim 1 , wherein the fixed bed hydroprocessing conditions comprise fixed bed hydrotreating conditions, fixed bed hydrocracking conditions, fixed bed demetallization conditions, or a combination thereof. 
     
     
         19 . The method of  claim 1 , wherein the hydroprocessing conditions comprise about 55 wt % or more conversion relative to 566° C., and wherein an I N  of at least one of the first hydroprocessed effluent and the second hydroprocessed effluent is 10 or more lower than an I N  of the feedstock. 
     
     
         20 . The method of  claim 19 , wherein a difference between an S BN  of the hydroprocessed effluent and the I N  of the hydroprocessed effluent is at least 30, or at least 40. 
     
     
         21 . A method for processing a heavy cracked feedstock, comprising:
 exposing a feedstock comprising a density at 15° C. of 1.06 g/cm 3  or more and at least 50 wt % of one or more 343° C.+ cracked fractions to a hydroprocessing catalyst under fixed bed hydroprocessing conditions to form a hydroprocessed effluent, the one or more 343° C.+ cracked fractions having an aromatics content of 40 wt % or more relative to a weight of the one or more 343° C.+ cracked fractions, a 343° C.+ portion of the hydroprocessed effluent having a density at 15° C. of 1.04 g/cm 3  or less;   separating, from the hydroprocessed effluent, a first fraction comprising a T10 distillation point of at least 260° C. and a T90 distillation point of 454° C. or less and a second fraction comprising a T10 distillation point of at least 427° C.; and   exposing at least a portion of the first fraction to a distillate hydroprocessing catalyst under distillate fixed bed hydroprocessing conditions to form a distillate hydroprocessing effluent.   
     
     
         22 . The method of  claim 21 , wherein a 177° C.-371° C. portion of the distillate hydroprocessing effluent has a sulfur content of 50 wppm or less (or 15 wppm or less). 
     
     
         23 . A system for processing a cracked feedstock, comprising:
 a first hydroprocessing reactor comprising a first hydroprocessing inlet, a first hydroprocessing outlet, and a fixed bed comprising a first hydroprocessing catalyst, the first hydroprocessing inlet comprising a feedstock comprising a density at 15° C. of 1.06 g/cm 3  or more and at least 50 wt % of one or more 343° C.+ cracked fractions, the one or more 343° C.+ cracked fractions having an aromatics content of 40 wt % or more relative to a weight of the one or more cracked fractions, the first hydroprocessing outlet comprising a hydroprocessed effluent;   a separation stage comprising a separation inlet, a first separation outlet, and a second separation outlet, the first separation inlet being in fluid communication with the first hydroprocessing outlet, a first separation outlet comprising a hydroprocessed effluent fraction having a T10 distillation point of at least 260° C. and a T90 distillation point of 454° C. or less, a second separation outlet comprising a hydroprocessed effluent fraction having a T10 distillation point of at least 427° C.; and   a second hydroprocessing reactor comprising a second hydroprocessing inlet, a second hydroprocessing outlet, and a fixed bed comprising a second hydroprocessing catalyst, the second hydroprocessing inlet being in fluid communication with the first separation outlet.   
     
     
         24 . The system of  claim 23 , wherein the first hydroprocessing inlet is in fluid communication with the second separation outlet. 
     
     
         25 . The system of  claim 23 , further comprising a fluid catalytic cracking reactor in indirect fluid communication with the second hydroprocessing outlet.