Jet and diesel selective hydrocracking

Abstract

Systems and methods are provided for processing of challenged feedstocks to produce distillate fuel products, such as jet boiling range products and/or diesel boiling range products. The challenged feedstocks can have a high aromatics content, a low API gravity, and/or a low cetane index/cetane number. A feedstock can be processed to form distillate fuel products by processing the feedstock in reaction system including at least two stages. The first stage can perform an initial amount of hydrotreating and/or hydrocracking, while the second stage can include exposing a portion of the hydrotreated and/or hydrocracked effluent to a USY catalyst including a supported noble metal. The USY catalyst can have a desirable combination of catalyst properties. Processing a challenged feedstock in a second stage with the USY catalyst having a desirable combination of properties can allow for production of an increased yield of distillate fuel from the challenged feedstock.

1 . A method for producing a fuel product fraction, comprising:
 hydroprocessing a feedstock having a T95 boiling point of about 850° F. (˜454° C.) or less under first hydroprocessing conditions to form a hydroprocessed effluent, the feedstock having an aromatics content of at least about 40 wt % and a cetane index of about 35 or less;   fractionating at least a portion of the hydroprocessed effluent to form at least a first fraction and a second fraction, the second fraction having a T5 boiling point of at least about 600° F. (˜316° C.);   hydrocracking at least a first portion of the second fraction in the presence of hydrocracking catalyst under second hydrocracking conditions to form a hydrocracked effluent, the hydrocracking catalyst comprising USY zeolite having a unit cell size of about 24.30 Å or less, a silica to alumina ratio of at least about 50, and an Alpha value of about 20 or less, the hydrocracking catalyst further comprising about 0.1 wt % to about 5.0 wt % of a Group 8-10 noble metal supported on the hydrocracking catalyst; and   fractionating at least a portion of the hydrocracked effluent to form at least a third fraction,   wherein the first fraction, the third fraction, or a combination thereof comprise a distillate boiling range product having an aromatics content of about 20 wt % or less and a cetane index of at least about 50.   
     
     
         2 . The method of  claim 1 , wherein fractionating at least a portion of the hydrocracked effluent further comprises forming a fourth fraction having a T5 boiling point of at least about 600° F. (˜316° C.), and wherein hydrocracking at least a first portion of the second fraction further comprises hydrocracking at least a portion of the fourth fraction. 
     
     
         3 . The method of  claim 2 , wherein the fractionation of the at least a portion of the hydroprocessed effluent and the fractionation of the at least a portion of the hydrocracked effluent are performed in a divided wall column fractionator, the second fraction being different from the fourth fraction. 
     
     
         4 . The method of  claim 2 , wherein the fractionation of the at least a portion of the hydroprocessed effluent and the fractionation of the at least a portion of the hydrocracked effluent are performed in a common fractionator, the second fraction and the fourth fraction being the same fraction. 
     
     
         5 . The method of  claim 1 , the method further comprising:
 separating the distillate boiling range product from the first fraction, the third fraction, or the combination thereof.   
     
     
         6 . The method of  claim 1 , wherein the feedstock has an API gravity of about 20.0 or less, and wherein the distillate boiling range product has an API gravity of at least about 33.0. 
     
     
         7 . The method of  claim 1 , wherein the hydrocracking catalyst comprises a USY zeolite having one or more or a unit cell size of about 24.24 Å or less, a silica to alumina ratio of at least about 85, and an Alpha value of about 10 or less. 
     
     
         8 . The method of  claim 1 , wherein the USY zeolite comprises a Meso-Y zeolite, an Extra Mesoporous Y zeolite, or a combination thereof. 
     
     
         9 . The method of  claim 1 , wherein hydroprocessing the feedstock comprising exposing the feedstock to a hydrotreating catalyst under hydrotreating conditions, or wherein hydroprocessing the feedstock comprises exposing the feedstock to a second hydrocracking catalyst under second hydrocracking conditions, or a combination thereof. 
     
     
         10 . The method of  claim 1 , the method further comprising exposing the hydrocracked effluent to a dewaxing catalyst under dewaxing conditions to form a hydrocracked, dewaxed effluent. 
     
     
         11 . The method of  claim 1 , wherein a yield of the distillate boiling range product is at least about 88 vol % relative to a ˜400° F.+(˜204° C.+) portion of the feedstock. 
     
     
         12 . The method of  claim 1 , wherein fractionating the at least a portion of the hydroprocessed effluent and the at least a portion of the hydrocracked effluent comprises forming a naphtha boiling range product, at least one of the first fraction and the third fraction optionally comprising the naphtha boiling range product, a combined yield of the naphtha boiling range fraction and the distillate boiling range product being at least about 110 vol % relative to the ˜400° F.+(˜204° C.+) portion of the feedstock. 
     
     
         13 . The method of  claim 12 , wherein a C 6+  yield is at least about 108 vol % relative to the ˜400° F.+(˜204° C.+) portion of the feedstock. 
     
     
         14 . The method of  claim 1 , wherein the distillate boiling range product has a naphthene content of at least about 50 wt %. 
     
     
         15 . A method for producing a fuel product fraction, comprising:
 hydroprocessing a feedstock having a T95 boiling point of about 850° F. (˜454° C.) or less under first hydroprocessing conditions to form a hydroprocessed effluent, the feedstock having an aromatics content of at least about 40 wt % and a cetane index of about 35 or less;   fractionating at least a portion of the hydroprocessed effluent to form at least a first fraction and a second fraction, the first fraction having a lower T5 boiling point than the second fraction, the second fraction having a T5 boiling point of about 300° F. (˜149° C.) to about 650° F. (˜343° C.);   hydrocracking at least a first portion of the second fraction in the presence of a hydrocracking catalyst under second hydrocracking conditions to form a hydrocracked effluent, the hydrocracking catalyst comprising USY zeolite having a unit cell size of about 24.30 Å or less, a silica to alumina ratio of at least about 50, and an Alpha value of about 20 or less, the hydrocracking catalyst further comprising about 0.1 wt % to about 5.0 wt % of a Group 8-10 noble metal supported on the hydrocracking catalyst; and   fractionating at least a portion of the hydrocracked effluent to form at least a third fraction and a fourth fraction, the third fraction having a lower T5 boiling point than the fourth fraction, the fourth fraction having a T5 boiling point of about 350° F. (˜177° C.) to about 650° F. (˜343° C.),   wherein the second fraction, the fourth fraction, or a combination thereof comprise a distillate boiling range product having a combined aromatics content of about 20 wt % or less and a cetane index of at least about 50.   
     
     
         16 . The method of  claim 15 , wherein the second fraction has a T5 boiling point of about 300° F. (˜149° C.) to about 450° F. (˜232° C.). 
     
     
         17 . The method of  claim 15 , wherein hydrocracking at least a first portion of the second fraction comprises hydrocracking at least a first portion of the second fraction and hydrocracking at least a portion of the fourth fraction. 
     
     
         18 . The method of  claim 15 , wherein the feedstock has a sulfur content of at least about 1.0 wt %, wherein the feedstock has a T95 boiling point of about 800° F. (˜427° C.) or less, wherein the feedstock has a T5 boiling point of about 350° F. (˜177° C.) to about 450° F. (˜232° C.), or a combination thereof. 
     
     
         19 . The method of  claim 15 , the method further comprising:
 separating the distillate boiling range product from the second fraction, the fourth fraction, or the combination thereof.   
     
     
         20 . A distillate boiling range fuel composition having a cetane index of at least about 50, an aromatics content of about 10 wt % or less, a naphthene content of at least about 50 wt %, a sulfur content of about 10 wppm or less, and an API gravity of at least about 35. 
     
     
         21 . A system for producing a fuel product fraction, comprising:
 a hydrotreating reactor comprising a hydrotreating feed inlet, a hydrotreating effluent outlet, and at least one fixed catalyst bed of a hydrotreating catalyst;   a separation stage having a first separation stage inlet and a second separation stage inlet, the first separation stage inlet being in fluid communication with the hydrotreating effluent outlet, the separation stage further comprising a plurality of separation stage liquid effluent outlets, one or more of the separation stage liquid effluent outlets corresponding to product outlets; and   a hydrocracking reactor comprising a hydrocracking feed inlet, a hydrocracking effluent outlet, and at least one fixed catalyst bed of a hydrocracking catalyst, the hydrocracking feed inlet being in fluid communication with at least one separation stage liquid effluent outlet, the hydrocracking effluent outlet being in fluid communication with the second separation stage inlet of the separation stage, and the hydrocracking catalyst comprising USY zeolite having a unit cell size of about 24.30 Å or less, a silica to alumina ratio of at least about 50, and an Alpha value of about 20 or less, the hydrocracking catalyst further comprising about 0.1 wt % to about 5.0 wt % of a Group 8-10 noble metal supported on the hydrocracking catalyst.   
     
     
         22 . The system of  claim 21 , wherein the separation stage comprises a divided wall column fractionator, the first separation stage inlet being different from the second separation stage inlet, the one or more product outlets being different from the at least one separation stage liquid effluent outlet in fluid communication with the hydrocracking feed inlet. 
     
     
         23 . The system of  claim 21 , wherein the separation stage comprises a common fractionator, the first separation stage inlet and the second separation stage inlet optionally comprising the same inlet. 
     
     
         24 . The system of  claim 21 , the system further comprising an additional hydrocracking reactor comprising an additional hydrocracking feed inlet, an additional hydrocracking effluent outlet, and at least one fixed catalyst bed of an additional hydrocracking catalyst, the additional hydrocracking reactor providing indirect fluid communication between the hydrotreating effluent outlet and the first separation stage inlet, the additional hydrocracking feed inlet being in fluid communication with the hydrotreating effluent outlet, the additional hydrocracking effluent outlet being in fluid communication with the first separation stage inlet.