Solvent extraction for correction of color and aromatics distribution of heavy neutral base stocks

Abstract

Systems and methods are provided for performing solvent extraction on heavy neutral base stocks. The aromatic extraction can reduce aromatics content while have a reduced or minimized impact on lubricant properties. This can allow, for example, for correction of color and/or haze for heavy neutral base stocks, such as heavy neutral base stocks formed from a deasphalted oil.

1 . A method for making lubricant base stock, comprising:
 hydroprocessing a deasphalted oil comprising a 370° C.+ fraction under first effective hydroprocessing conditions to form a hydroprocessed effluent, at least a portion of the deasphalted oil having an aromatics content of at least about 50 wt %, the hydroprocessed effluent comprising a sulfur content of 300 wppm or less or a nitrogen content of 100 wppm or less, or a combination thereof;   separating the hydroprocessed effluent to form at least a first fraction comprising a T5 distillation point of at least 370° C. and a kinematic viscosity at 100° C. of 6 cSt to 20 cSt;   hydroprocessing at least a portion of the first fraction under second effective hydroprocessing conditions, the second effective hydroprocessing conditions comprising catalytic dewaxing conditions, to form a catalytically dewaxed effluent comprising a 370° C.+ portion; and   solvent extracting at least a portion of the 370° C.+ portion of the catalytically dewaxed effluent to form a solvent processed effluent.   
     
     
         2 . A method for making lubricant base stock, comprising:
 performing solvent deasphalting, optionally using a C 4+  solvent, under effective solvent deasphalting conditions on a feedstock having a T5 boiling point of at least about 370° C. (or at least about 400° C., or at least about 450° C., or at least about 500° C.), the effective solvent deasphalting conditions producing a yield of deasphalted oil of at least about 50 wt % of the feedstock;   hydroprocessing at least a portion of the deasphalted oil under first effective hydroprocessing conditions to form a hydroprocessed effluent, the at least a portion of the deasphalted oil having an aromatics content of at least about 50 wt %, the hydroprocessed effluent comprising a sulfur content of 300 wppm or less, a nitrogen content of 100 wppm or less, or a combination thereof;   separating the hydroprocessed effluent to form at least a first fraction comprising a T5 distillation point of at least 370° C. and a kinematic viscosity at 100° C. of 6 cSt to 20 cSt;   hydroprocessing at least a portion of the first fraction under second effective hydroprocessing conditions, the second effective hydroprocessing conditions comprising catalytic dewaxing conditions, to form a catalytically dewaxed effluent comprising a 370° C.+ portion; and   solvent extracting at least a portion of the 370° C.+ portion of the catalytically dewaxed effluent to form a solvent processed effluent.   
     
     
         3 . A method for making lubricant base stock, comprising:
 hydroprocessing a feedstock comprising a 370° C.+ fraction under first effective hydroprocessing conditions to form a hydroprocessed effluent, the at least a portion of the deasphalted oil having an aromatics content of at least about 50 wt %, the hydroprocessed effluent comprising a sulfur content of 300 wppm or less, a nitrogen content of 100 wppm or less, or a combination thereof;   separating the hydroprocessed effluent to form at least a first fraction having a T5 distillation point of at least 370° C.;   hydroprocessing at least a portion of the first fraction under second effective hydroprocessing conditions, the second effective hydroprocessing conditions comprising catalytic dewaxing conditions, to form a catalytically dewaxed effluent comprising a 370° C.+ portion, the 370° C.+ portion comprising a second fraction comprising a kinematic viscosity at 100° C. of 6 cSt to 20 cSt; and   solvent extracting at least a portion of the second fraction to form a solvent processed effluent.   
     
     
         4 . A method for making lubricant base stock, comprising:
 performing solvent deasphalting, optionally using a C 4+  solvent, under effective solvent deasphalting conditions on a feedstock having a T5 boiling point of at least about 370° C. (or at least about 400° C., or at least about 450° C., or at least about 500° C.), the effective solvent deasphalting conditions producing a yield of deasphalted oil of at least about 50 wt % of the feedstock;   hydroprocessing at least a portion of the deasphalted oil under first effective hydroprocessing conditions to form a hydroprocessed effluent, the at least a portion of the deasphalted oil having an aromatics content of at least about 50 wt %, the hydroprocessed effluent comprising a sulfur content of 300 wppm or less, a nitrogen content of 100 wppm or less, or a combination thereof;   separating the hydroprocessed effluent to form at least a first fraction comprising a T5 distillation point of at least 370° C.;   hydroprocessing at least a portion of the first fraction under second effective hydroprocessing conditions, the second effective hydroprocessing conditions comprising catalytic dewaxing conditions, to form a catalytically dewaxed effluent comprising a 370° C.+ portion, the 370° C.+ portion comprising a second fraction comprising a kinematic viscosity at 100° C. of 6 cSt to 20 cSt; and   solvent extracting at least a portion of the second fraction to form a solvent processed effluent.   
     
     
         5 . The method of  claim 3 , further comprising separating at least a portion of the catalytically dewaxed effluent to form the second fraction or separating at least a portion of the 370° C.+ portion of the catalytically dewaxed effluent to form the second fraction. 
     
     
         6 . The method of  claim 4 , wherein the solvent processed effluent comprises a VI of at least 80 and a kinematic viscosity at 100° C. of 6 cSt to 20 cSt. 
     
     
         7 . The method of  claim 1 , wherein the solvent processed effluent comprises a pour point of −6° C. or less, a cloud point of −2° C. or a combination thereof. 
     
     
         8 . The method of  claims 1 - 4 , wherein the solvent extracting comprises solvent extracting with N-methylpyrrolidone, furfural, phenol, or a combination thereof. 
     
     
         9 . The method of  claim 2 , wherein the yield of deasphalted oil is at least 55 wt %, wherein the deasphalted oil has an aromatics content of at least 55 wt %, based on a weight of the deasphalted oil, or a combination thereof. 
     
     
         10 . The method of  claim 2 , wherein the C 4+  solvent comprises a C 5+  solvent, a mixture of two or more C 5  isomers, or a combination thereof. 
     
     
         11 . The method of  claim 2 , wherein the solvent processed effluent comprises a viscosity index of 80 to 160. 
     
     
         12 . The method of  claim 2 , wherein prior to the solvent extracting, the 370° C.+ portion of the catalytically dewaxed effluent or the second fraction comprises an absorptivity at 226 nm of at least 0.020 and the 370° C.+ portion of the catalytically dewaxed effluent or the second fraction after extraction comprising an absorptivity at 226 nm of less than 0.020. 
     
     
         13 . The method of  claim 2 , wherein prior to the solvent extracting, the 370° C.+ portion of the catalytically dewaxed effluent or the second fraction comprises an absorptivity at 254 nm of at least 0.010, the 370° C.+ portion of the catalytically dewaxed effluent or the second fraction after extraction comprising an absorptivity at 254 nm of less than 0.010. 
     
     
         14 . The method of  claim 2 , wherein prior to the solvent extracting, the 370° C.+ portion of the catalytically dewaxed effluent or the second fraction comprises an absorptivity at 275 nm of at least 0.010, and the 370° C.+ portion of the catalytically dewaxed effluent or the second fraction after extraction comprising an absorptivity at 275 nm of less than 0.010. 
     
     
         15 . The method of  claim 1 , wherein prior to the solvent extracting, the 370° C.+ portion of the catalytically dewaxed effluent or the second fraction comprises an absorptivity at 302 nm of at least 0.020, the 370° C.+ portion of the catalytically dewaxed effluent or the second fraction after extraction comprising an absorptivity at 302 nm of less than 0.010. 
     
     
         16 . The method of  claim 2 , wherein prior to the solvent extracting, the 370° C.+ portion of the catalytically dewaxed effluent or the second fraction comprises an absorptivity at 310 nm of at least 0.030, the 370° C.+ portion of the catalytically dewaxed effluent or the second fraction after extraction comprising an absorptivity at 310 nm of less than 0.010. 
     
     
         17 . The method of  claim 3 , wherein prior to the solvent extracting, the 370° C.+ portion of the catalytically dewaxed effluent or the second fraction comprises an absorptivity at 325 nm of at least 0.010, the 370° C.+ portion of the catalytically dewaxed effluent or the second fraction after extraction comprising an absorptivity at 310 nm of less than 0.010. 
     
     
         18 . A solvent processed effluent produced according to  claim 1 . 
     
     
         19 . A formulated lubricant formed from the solvent processed effluent of  claim 18  with the formulated lubricant optionally comprising an additive. 
     
     
         20 . The formulated lubricant of  claim 19 , wherein the additive is selected from the group consisting of detergents, dispersants, antioxidants, viscosity modifiers, pour point depressants, antiwear agents, corrosion inhibitors, rust inhibitors, metal deactivators, extreme pressure additives, anti-seizure agents, wax modifiers, viscosity index improvers, viscosity modifiers, fluid-loss additives, seal compatibility agents, friction modifiers, lubricity agents, anti-staining agents, chromophoric agents, defoamants, demulsifiers, emulsifiers, densifiers, wetting agents, gelling agents, tackiness agents, colorants, and combinations thereof.