Integrated lubricant upgrading process using once-through, hydrogen-containing treat gas

Abstract

The invention relates to a process for producing lube oil basestocks involving solvent extracting a waxy feed to produce at least a lube oil boiling-range raffinate. The lube oil raffinate is hydrotreated to produce a hydrotreated raffinate, which is dewaxed and hydrofinished.

1 . A process to prepare a lubricating oil basestock comprising: 
 (a) contacting a lube oil boiling-range raffinate feed containing nitrogen and sulfur heteroatoms with a catalytically effective amount of a hydrotreating catalyst in a first reaction stage operated under effective hydrotreating conditions in the presence of a hydrogen-containing gaseous product from a third reaction stage to produce a hydrotreated raffinate;    (b) stripping the hydrotreated raffinate by contacting the hydrotreated raffinate with a first once-through, hydrogen-containing treat gas to separate sulfur-containing and nitrogen-containing species from the hydrotreated raffinate to produce a stripped raffinate;    (c) contacting the stripped raffinate with a catalytically effective amount of a hydrodewaxing catalyst in the presence of a second once-through, hydrogen-containing treat gas in a second reaction stage operated under effective hydrodewaxing conditions to produce a second-stage reaction product comprising a second-stage gaseous product and a second-stage liquid product, wherein the second-stage gaseous product comprises hydrogen and the second-stage liquid product comprises a dewaxed raffinate;    (d) cascading, without disengagement, at least a portion of the second reaction stage product to a hydrofinishing reaction stage;    (e) contacting the cascaded portion of the second reaction stage product with a catalytically effective amount of a hydrofinishing catalyst in the third reaction stage operated under effective hydrofinishing conditions to produce a third-stage reaction product comprising the third-stage gaseous product comprising hydrogen and a third-stage liquid product comprising a lubricating oil basestock, wherein said second-stage gaseous product provides hydrogen for the third reaction stage;    (f) separating the third-stage gaseous product from the third-stage reaction product; and    (g) cascading the third-stage gaseous product, without heteroatom disengagement, to the first reaction stage.    
   
   
       2 . The process according to  claim 1  wherein said lube oil boiling-range raffinate feed is produced by: 
 (a) extracting a lubricating oil feed in a solvent extraction zone with an extraction solvent under conditions effective to produce at least an aromatics-lean raffinate solution containing extraction solvent; and    (b) removing at least a portion of the extraction solvent from the aromatics-lean raffinate solution to produce at least a lube oil boiling-range raffinate feed.    
   
   
       3 . The process according to  claim 2  wherein the lubricating oil feed has a 10% distillation point greater than 650° F. (343° C.), measured by ASTM D 86 or ASTM 2887, and are derived from mineral sources, synthetic sources, or a mixture of the two.  
   
   
       4 . The process according to  claim 2  wherein the lubricating oil feed is one or more oil selected from raffinates, partially solvent dewaxed oils, deasphalted oils, distillates, vacuum gas oils, coker gas oils, slack waxes, foots oils and the like, dewaxed oils, and Fischer-Tropsch waxes.  
   
   
       5 . The process according to  claim 2  wherein the lubricating oil feed contains up to 0.2 wt. % of nitrogen, based on the weight of the lubricating oil feed, and up to 3.0 wt. % of sulfur, based on the weight of the lubricating oil feed.  
   
   
       6 . The process according to  claim 1  wherein said hydrodewaxing catalyst is selected from ZSM-5, ZSM-22, ZSM-23, ZSM-35, ZSM-48, ZSM-57, Beta, SSZ-31, SAPO-11, SAPO-31, SAPO-41, MAPO-11, ECR-42, fluorided alumina, silica-alumina, fluorided silica alumina, synthetic Ferrierites, Mordenite, Offretite, erionite, chabazite, and mixtures thereof.  
   
   
       7 . The process according to  claim 6  wherein the hydrodewaxing catalyst further comprises at least one metal hydrogenation component, which is selected from Group VIB metals, Group VIII metals, or mixtures thereof.  
   
   
       8 . The process according to  claim 1  wherein the hydrodewaxing catalyst comprises a zeolite.  
   
   
       9 . The process according to  claim 8  wherein the zeolite is selected from ZSM-48, ZSM-22 and ZSM-23.  
   
   
       10 . The process according to  claim 6  wherein the hydrodewaxing catalyst further comprises a binder material selected from inorganic oxides containing one or more of silica, alumina, titania, magnesia, thoria, and zirconia.  
   
   
       11 . The process according to  claim 1  wherein the effective hydrodewaxing conditions include a temperature from about 250° C. to about 400° C., a pressure from about 0.7 MPa to about 20.8 MPa (about 100 to 3000 psig), a liquid hourly space velocity from about 0.1 to about 10 hr −1 , and a once-through, hydrogen-containing treat gas rate from about 45 to about 1780 m 3 /m 3  (250 to 10000 SCF H 2 /B); and wherein the first and second once-through, hydrogen-containing treat gases are fresh and are obtained from a common fresh treat gas source.  
   
   
       12 . The process according to  claim 1  wherein the hydrotreating catalyst is selected from supported hydrotreating catalysts comprising about 2 to 20 wt. % of at least one Group VIII metal, and about 5 to 50 wt. % of at least one Group VI metal, on a support material.  
   
   
       13 . The process according to  claim 12  wherein the Group VIII metal is Co and/or Ni, and mixtures thereof, and wherein the Group VI metal is Mo and/or W.  
   
   
       14 . The process according to  claim 1  wherein the effective hydrotreating conditions include a temperature from about 150° C. to about 400° C., a hydrogen partial pressure from about 1.48 to about 20.8 MPa (200 to 3000 psig), a space velocity from about 0.1 to about 10 liquid hourly space velocity (LHSV), and a hydrogen to feed ratio from about 89 to about 1780 m 3 /m 3  (500 to 10000 SCF H 2 /B).  
   
   
       15 . The process according to  claim 14  wherein the effective hydrotreating conditions are selected such that cracking of the lube oil boiling-range raffinate feed is limited to less than 10 wt. % conversion, based on the weight of the lube oil boiling-range raffinate feed.  
   
   
       16 . The process according to  claim 1  wherein the hydrofinishing catalyst comprises a support and at least one metal selected from Group VIB metals, Group VIII metals, and mixtures thereof.  
   
   
       17 . The process according to  claim 1  wherein the support comprises amorphous or crystalline oxide materials containing one or more of alumina, silica, and silica—alumina.  
   
   
       18 . The process according to  claim 1  wherein the hydrofinishing catalyst comprises a mesoporous material belonging to the M41S class or family of catalysts.  
   
   
       19 . The process according to  claim 18  wherein the mesoporous material is selected from MCM-41, MCM-48 and MCM-50.  
   
   
       20 . The process according to  claim 9  wherein the zeolite is ZSM-48, and wherein the hydrofinishing catalyst comprises MCM-41.  
   
   
       21 . The process according to  claim 18  wherein the hydrofinishing catalyst comprising a mesoporous material further comprises at least one metallic hydrogenation component, and wherein the hydrofinishing conditions include temperatures from about 150° C. to about 350° C., total pressure ranges from about 2.86 MPa to about 20.8 MPa (about 400 to 3000 psig), liquid hourly space velocity from about 0.1 to about 5 LHSV (hr −1 ), hydrogen treat gas rates of from about 44.5 to about 1780 m 3 /m 3  (250 to 10,000 SCF H 2 /B), and hydrogen partial pressure ranges from about 1.48 MPa to about 20.4 MPa (about 200 psig to about 3000 psig).  
   
   
       22 . The process according to  claim 1 , further comprising separating at least one lubricating oil basestock from the third-stage reaction product.  
   
   
       23 . The process of  claim 22 , further comprising adding to a major amount of the lubricating oil basestock a minor amount of at least one additive to make a finished lubricating oil product.  
   
   
       24 . A process to prepare lubricating oil basestocks from lube oil boiling-range raffinate feed comprising: 
 (a) extracting a lubricating oil feedstock in a solvent extraction zone with an extraction solvent under conditions effective at producing at least an aromatics-lean raffinate solution containing extraction solvent;    (b) separating at least a portion of the extraction solvent from the aromatics-lean raffinate solution to produce at least a lube oil boiling-range raffinate feed;    (c) contacting a lube oil boiling-range raffinate feed containing nitrogen and sulfur heteroatoms with a catalytically effective amount of hydrotreating catalyst in a first reaction stage operated under effective hydrotreating conditions in the presence of a hydrogen-containing gaseous product from a third reaction stage to produce a hydrotreated raffinate;    (d) stripping the hydrotreated raffinate by contacting the hydrotreated raffinate with first fresh, once-through, hydrogen-containing treat gas to separate sulfur-containing and nitrogen-containing species from the hydrotreated raffinate to produce a stripped raffinate;    (e) contacting the stripped raffinate with a catalytically effective amount of a hydrodewaxing catalyst in the presence of the fresh once-through, hydrogen-containing treat gas in a second reaction stage operated under effective hydrodewaxing conditions to produce a second-stage reaction product comprising at least a second-stage gaseous product and a second-stage liquid product, wherein the second-stage gaseous product comprises hydrogen and the second-stage liquid product comprising a dewaxed raffinate;    (f)) cascading, without disengagement, at least a portion of the second reaction stage product to a hydrofinishing reaction stage;    (g) contacting the cascaded portion of the second-reaction stage product with a catalytically effective amount of a hydrofinishing catalyst in the third reaction stage operated under effective hydrofinishing conditions to produce a third stage reaction product comprising the third stage gaseous product comprising hydrogen and a third-stage liquid product comprising a lubricating oil basestock, wherein the second-stage gaseous product provides hydrogen for the third reaction stage.    (h) separating the third-stage gaseous product from the third-stage reaction product; and    (i) cascading the third-stage gaseous product, without heteroatom disengagement, to the first reaction stage.