Process to produce synthetic fuels and lubricants

Abstract

A process utilizing a low severity hydrocracker prior to a high severity hydrocracker for the processing of petroleum based and synthetic hydrocarbon feedstocks into distillate fuels and high quality lubricant base oils. The process minimizes the size and conditions required by the high severity hydrocracker by closely matching such configuration with the desired product slate.

1 . A process to produce synthetic lubricants and fuels comprising the steps of: 
 (a) fractionating a feedstock into a first distillate comprising C5 to 320° F. hydrocarbons, and a second distillate comprising 320° F. to 700° F. hydrocarbons, and a third distillate comprising 700° F.+hydrocarbons;    (b) hydrocracking the third distillate in a low severity hydrocracker to produce a hydrocrackate;    (c) feeding the second distillate to a second fractionator;    (c) feeding the hydrocrackate to the second fractionator;    (d) recovering from the second fractionator a first distillate fuel fraction, a light lubricant fraction, and a waxy lubricant fraction;    (e) hydrodewaxing the waxy lubricant fraction to form a dewaxed product;    (f) fractionating the dewaxed product in a third fractionator.    
     
     
         2 . The process of  claim 1  further comprising the step of: 
 (a1) hydrotreating the second distillate prior to feeding into the second fractionator.    
     
     
         3 . The process of  claim 1  further comprising the step of: 
 (a2) hydrotreating the third distillate prior to hydrocracking in step (b).    
     
     
         4 . The process of  claim 1  wherein the second distillate and the hydrocrackate are combined prior to being fed into the second fractionator.  
     
     
         5 . The process of  claim 1  further comprising the step of: 
 (e1) hydrofinishing the dewaxed product prior to fractionating step (f).    
     
     
         6 . The process of  claim 1  further comprising the step of: 
 (g) recovering a second distillate fuel fraction from the third fractionator.    
     
     
         7 . The process of  claim 1  further comprising the step of: 
 (h) recovering one or more lubricant base oil fractions from the third fractionator.    
     
     
         8 . The process of  claim 1  further comprising the step of: 
 (i) recovering a raffinate from the third fractionator;    (j) hydrocracking the raffinate in a high severity hydrocracker; and    (k) recycling the effluent of the high severity hydrocracker to the second fractionator.    
     
     
         9 . The process of  claim 1  wherein the light lubricant stream is processed through steps (e) and (f).  
     
     
         10 . The process of  claim 1  further comprising the steps of: 
 (m) hydrocracking a part of the waxy lubricant fraction in a high severity hydrocracker; and    (n) recylcing the effluent from the high severity hydrocracker into the second fractionator.    
     
     
         11 . A process to produce synthetic lubricants and fuels comprising the steps of: 
 (a) fractionating a feedstock into a first distillate comprising C5 to 320° F. hydrocarbons, and a second distillate comprising 320° F. to 700° F. hydrocarbons, and a third distillate comprising 700° F.+hydrocarbons;    (b) hydrocracking the third distillate in a low severity hydrocracker to produce a hydrocrackate;    (c) feeding the second distillate to a second fractionator    (c) feeding the hydrocrackate to the second fractionator;    (d) recovering from the second fractionator a first distillate fuel fraction, a light lubricant fraction, a lubricant fraction, and a waxy raffinate;    (e) hydrodewaxing the lubricant fraction to form a dewaxed product;    (f) fractionating the dewaxed product in a third fractionator.    
     
     
         12 . The process of  claim 11  further comprising the step of: 
 (a1) hydrotreating the second distillate prior to feeding into the second fractionator.    
     
     
         13 . The process of  claim 11  further comprising the step of: 
 (a2) hydrotreating the third distillate prior to hydrocracking in step (b).    
     
     
         14 . The process of  claim 11  wherein the second distillate and the hydrocrackate are combined prior to being fed into the second fractionator.  
     
     
         15 . The process of  claim 11  further comprising the step of: 
 (e1) hydrofinishing the dewaxed product prior to fractionating step (f).    
     
     
         16 . The process of  claim 11  further comprising the step of: 
 (g) recovering a second distillate fuel fraction from the third fractionator.    
     
     
         17 . The process of  claim 11  further comprising the step of: 
 (h) recovering one or more lubricant base oil fractions from the third fractionator.    
     
     
         18 . The process of  claim 11  further comprising the steps of: 
 (i) hydrocracking the waxy raffinate in a high severity hydrocracker; and    (j) recylcing the effluent of the high severity hydrocracker into the second fractionator.    
     
     
         19 . The process of  claim 11  wherein the light lubricant stream is processed through steps (e) and (f).  
     
     
         20 . The process of  claim 1  wherein the feedstock is all or part of the product of a Fischer-Tropsch synthesis.  
     
     
         21 . The process of  claim 1  wherein the feedstock is selected from the group of heavy gas oil and vacuum gas oil.  
     
     
         22 . The process of  claim 11  wherein the feedstock is all or part of the product of a Fischer-Tropsch synthesis.  
     
     
         23 . The process of  claim 11  wherein the feedstock is selected from the group of heavy gas oil and vacuum gas oil.  
     
     
         24 . The process of  claim 1  wherein the process conditions of the low severity hydrocracker are between about 400° F. and about 750° F., between about 200 and abut 3000 psig, between about 1000 and about 20000 SCF/BBL, and between about 0.25 and about 10 LHSV.  
     
     
         25 . The process of  claim 1  wherein the process conditions of the high severity hydrocracker are between about 400° F. and about 800° F., between about 200 and abut 3000 psig, between about 1000 and about 20000 SCF/BBL, and between about 0.1 and about 5 LHSV.  
     
     
         26 . The process of  claim 11  wherein the process conditions of the low severity hydrocracker are between about 400° F. and about 750° F., between about 200 and abut 3000 psig, between about 1000 and about 20000 SCF/BBL, and between about 0.25 and about 10 LHSV.  
     
     
         27 . The process of  claim 11  wherein the process conditions of the high severity hydrocracker are between about 400° F. and about 800° F., between about 200 and abut 3000 psig, between about 1000 and about 20000 SCF/BBL, and between about 0.1 and about 5 LHSV.