Process for increased production of fcc gasoline

Abstract

This invention relates to methods and processes for increasing the production of FCC (Fluid Catalytic Cracking) gasoline products, and optionally distillate products, from refinery feedstocks. In particular, the processes include hydrotreating and further hydroisomerizing a typical FCC range feedstream prior to catalytically cracking the feedstream in the FCC unit. The methods herein result in higher FCC naphtha yields and lower FCC cat bottoms yields thereby significantly increasing the overall FCC gasoline production for a given operating unit and increasing the profit margin of such FCC unit operations.

What is claimed is: 
     
         1 . A process for increasing Fluid Catalytic Cracking (“FCC”) gasoline production comprising:
 a) contacting a hydrocarbon-containing hydroisomerization feedstream with a hydroisomerization catalyst under hydroisomerization conditions to produce at least one hydroisomerized liquid product stream that has a higher iso-paraffin content than the hydroisomerization feedstream; 
 b) contacting in the reaction zone of an FCC reactor riser an FCC feedstream comprising at least a portion of the hydroisomerized liquid product stream of step a) with a fluid catalytic cracking catalyst thereby catalytically cracking the FCC feedstream into an FCC product that has an average lower boiling point than the FCC feedstream, and producing a spent catalyst; 
 c) the FCC product from the spent catalyst; 
 d) cooling the FCC product; and 
 e) fractionating the FCC product into multiple FCC product streams, wherein at least one of the FCC product streams is a naphtha boiling-range product stream; and 
 f) utilizing at least a portion of the naphtha boiling-range product stream for gasoline production. 
 
     
     
         2 . The process of  claim 1 , wherein at least 50 wt % of the normal paraffins in the hydroisomerization feedstream are converted to iso-paraffins in the hydroisomerized liquid product stream in step a). 
     
     
         3 . The process of  claim 2 , wherein the hydroisomerization catalyst comprises at least one Group VIIIA metal, and further comprises a zeolite selected from EU-1, ZSM-35, ZSM-11, ZSM-57, NU-87, SAPO-11, ZSM-22, and ZSM-48. 
     
     
         4 . The process of  claim 3 , wherein the Group VIIIA metal of the hydroisomerization catalyst is selected from Pt and Pd. 
     
     
         5 . The process of  claim 3 , wherein the hydroisomerization catalyst further comprises at least one Group VIA metal, wherein the Group VIA of the hydroisomerization catalyst is selected from Mo and W, and the Group VIIIA metal of the hydroisomerization catalyst is selected from Ni and Co. 
     
     
         6 . The process of  claim 5 , wherein the Group VIA of the hydroisomerization catalyst is W, the Group VIIIA metal of the hydroisomerization catalyst is Ni, and the zeolite in the hydroisomerization catalyst is ZSM-48. 
     
     
         7 . The process of  claim 5 , wherein tire hydroisomerization feedstream contains over 300 ppmw of sulfur. 
     
     
         8 . The process of  claim 3 , wherein the hydroisomerization conditions include a temperature of from 400 to 850° F. (204 to 454° C.), a hydrogen partial pressure of from 1.8 to 34.6 mPa (250 to 5000 psi), a liquid hourly space velocity of from 0.2 to 10 v/v/hr, and a hydrogen circulation rate of from 35.6 to 1781 m 3 /m 3  (200 to 10,000 scf/B). 
     
     
         9 . The process of  claim 8 , wherein the conditions in the reaction zone of the FCC reactor include a temperature from about 900 to about 1060° F. (482 to 57° C.), a hydrocarbon partial pressure from about 10 to 50 psia (70-345 kPa), and a catalyst to feed (wt/wt) ratio from about 3 to 8, where the catalyst weight is total weight of the fluid catalytic cracking catalyst. 
     
     
         10 . The process of  claim 9 , wherein the fluid catalytic cracking catalyst comprises at least one large-pore size faujasite zeolite and at least one medium-pore size zeolite selected from ZSM-5, ZSM-12, ZSM-22, ZSM-23, ZSM-34, ZSM-35, ZSM-38, ZSM-48, ZSM-50, silicalite, and silicalite 2. 
     
     
         11 . The process of  claim 10 , wherein feed residence time in the reaction zone of the FCC reactor riser is less than about 5 seconds. 
     
     
         12 . The process of  claim 1 , wherein the at least one hydroisomerized liquid product stream of step a) is sent to a distillation column of to produce the at least a portion of the hydroisomerized liquid product stream of step b), as well as producing a distillation column overhead vapor stream and at least a first distillate product stream from the distillation column, wherein the distillation column overhead vapor stream and the first distillate product stream are not sent to the reaction zone of the FCC reactor riser. 
     
     
         13 . The process of  claim 12 , wherein at least one of the FCC product streams is an FCC distillate boiling-range product stream and at least a portion of the first distillate product stream is combined with at least a portion of the FCC distillate boiling-range product stream to form a combined distillate product stream. 
     
     
         14 . The process of  claim 13 , wherein at least a portion of the combined distillate product stream is utilized for diesel product blending. 
     
     
         15 . The process of  claim 1 , further comprising:
 contacting a hydrocarbon-containing hydrotreater feedstream containing at least 250 ppmw of sulfur with a hydrotreating catalyst under hydrotreating conditions to produce at least one hydrotreated liquid product stream and one hydrotreated vapor stream, wherein the hydrotreated liquid product stream has a lower sulfur content than the sulfur-containing hydrocarbon feedstream;   separating the hydrotreated liquid product stream from the hydrotreated vapor stream; and   utilizing at least a portion of the hydrotreated liquid product stream as the hydroisomerization feedstream in step a).   
     
     
         16 . The process of  claim 15 , wherein the hydrotreated liquid product stream contains less than 30 ppmw of sulfur. 
     
     
         17 . The process of  claim 15 , wherein the hydrotreating catalyst comprises at least one Group VIA metal and at least one Group VIIIA metal on a refractory oxide support, wherein the refractory oxide support comprises silica, alumina, or silica-alumina; and the hydroisomerization catalyst is comprised of at least one Group VIIIA metal, and a zeolite selected from EU-1, ZSM-35, ZSM-11, ZSM-57, NU-87, SAPO-11, ZSM-22, and ZSM-48. 
     
     
         18 . The process of  claim 17 , wherein the hydrotreating catalyst has a has an average pore size of from about 100 Å to about 1000 Å, and a surface area of from about 100 to 350 m 2 /g. 
     
     
         19 . The process of  claim 15 , wherein the hydrotreating conditions include a temperature in the range 450° F. to 750° F. (232° C. to 399° C.), pressure in the range of 1480 to 20786 kPa (200 to 3000 psig), a space velocity of from 0.1 to 10 LHSV, and a hydrogen treat gas rate of from 18 to 890 m 3 /m 3  (100 to 5000 scf/B). 
     
     
         20 . The process of  claim 17 , wherein the Group VIIIA metal of the hydroisomerization catalyst is selected from Pt and Pd. 
     
     
         21 . The process of  claim 17 , wherein the hydroisomerization catalyst further comprises at least one Group VIA metal, wherein the Group VIA of the hydroisomerization catalyst is selected from Mo and W, and the Group VIIIA metal of the hydroisomerization catalyst is selected from Ni and Co. 
     
     
         22 . The process of  claim 17 , wherein the at least one hydroisomerized liquid product stream of step a) is sent to a distillation column of to produce the at least a portion of the hydroisomerized liquid product stream of step b), as well as producing an distillation column overhead vapor stream and at least a first distillate product stream from the distillation column, wherein the distillation column overhead vapor stream and the first distillate product stream are not sent to the reaction zone of the FCC reactor riser. 
     
     
         23 . The process of  claim 22 , wherein at least one of tire FCC product streams is an FCC distillate boiling-range product stream and at least a portion of the first distillate product stream is combined with at least a portion of the FCC distillate boiling-range product stream to form a combined distillate product stream. 
     
     
         24 . The process of  claim 17 , wherein the hydrotreater feedstream has a T5 boiling point of at least 400° F. and a T95 boiling point of less than about 1150° F. 
     
     
         25 . The process of  claim 24 , wherein the hydrotreater feedstream is comprised of at least 75 wt % of a hydrocarbon feedstream derived from a fossil-based oil material, and is further comprised of from 5 to 25 wt % of oil derived from renewable biofuel sources. 
     
     
         26 . The process of  claim 1 , further comprising:
 contacting a hydrocarbon-containing hydrotreater feedstream containing at least 250 ppmw of sulfur with a hydrotreating catalyst under hydrotreating conditions to produce the hydroisomerization feedstream.   
     
     
         27 . The process of  claim 26 , wherein the hydrotreating catalyst and the hydroisomerization catalyst are in a single reactor. 
     
     
         28 . The process of  claim 26 , wherein the hydrotreating catalyst comprises at least one Group VIA metal and at least one Group VIIIA metal on a refractory oxide support, wherein the refractory oxide support comprises silica, alumina, or silica-alumina; and the hydroisomerization catalyst is comprised of at least one Group VIIIA metal, and a zeolite selected from EU-1, ZSM-35, ZSM-11, ZSM-57, NU-87, SAPO-11, ZSM-22, and ZSM-48. 
     
     
         29 . The process of  claim 28 , wherein the hydroisomerization catalyst further comprises at least one Group VIA metal, wherein the Group VIA of the hydroisomerization catalyst is selected from Mo and W, and the Group VIIIA metal of the hydroisomerization catalyst is selected from Ni and Co. 
     
     
         30 . The process of  claim 29 , wherein the zeolite in the hydroisomerization catalyst is ZSM-48. 
     
     
         31 . The process of  claim 29 , wherein the at least one hydroisomerized liquid product stream of step a) is sent to a distillation column of to produce the at least a portion of the hydroisomerized liquid product stream of step b), as well as producing an distillation column overhead vapor stream and at least a first distillate product stream from the distillation column, wherein the distillation column overhead vapor stream and the first distillate product stream are not sent to the reaction zone of the FCC reactor riser. 
     
     
         32 . The process of  claim 31 , wherein at least one of the FCC product streams is an FCC distillate boiling-range product stream and at least a portion of the first distillate product stream is combined with at least a portion of the FCC distillate boiling-range product stream to form a combined distillate product stream. 
     
     
         33 . The process of  claim 28 , wherein the hydrotreater feedstream has a T5 boiling point of at least 400° F. and a T95 boiling point of less than about 1150° F. 
     
     
         34 . The process of  claim 33 , wherein the hydrotreater feedstream is comprised of at least 75 wt % of a hydrocarbon feedstream derived from a fossil-based oil material, and is further comprised of from 5 to 25 wt % of oil derived from renewable biofuel sources. 
     
     
         35 . A process for increasing Fluid Catalytic Cracking (“FCC”) gasoline production comprising:
 a) contacting a hydrocarbon-containing hydroisomerization feedstream with a hydroisomerization catalyst under hydroisomerization conditions to produce at least one hydroisomerized product stream that has a higher iso-paraffin content than the hydroisomerization feedstream; 
 b) contacting at least a portion of the hydroisomerized product stream with a hydrotreating catalyst under hydrotreating conditions to produce at least one hydrotreated liquid product stream and one hydrotreated vapor stream, wherein the hydrotreated liquid product stream has a lower sulfur content than the sulfur-containing hydrocarbon feedstream; 
 c) separating the hydrotreated liquid product stream from the hydrotreated vapor stream; 
 d) contacting in the reaction zone of an FCC reactor riser an FCC feedstream comprising at least a portion of the hydrotreated liquid product stream of step c) with a fluid catalytic cracking catalyst thereby catalytically cracking the FCC feedstream into an FCC product that has an average lower boiling point than the FCC feedstream, and producing a spent catalyst; 
 e) separating the FCC product from the spent catalyst; 
 f) cooling the FCC product; and 
 e) fractionating the FCC product into multiple FCC product streams, wherein at least one of the FCC product streams is a naphtha boiling-range product stream; and 
 g) utilizing at least a portion of the naphtha boiling-range product stream for gasoline production.