Co-extraction of a hydrocarbon material and extract obtained by solvent extraction of a second hydrotreated material

Abstract

The present invention relates to a process to increase extraction yields and improve dewaxing performance of a lube boiling range stream. More particularly, the present invention is a process to produce at least one base oil by contacting a light lube stream with a polar solvent in a solvent extraction zone, then mixing the resulting extract with a second, heavier lube stream, extracting the mixture with a polar solvent, and dewaxing the resultant raffinate.

1 . A process to improve dewaxing performance and extraction yields of a lube boiling range stream comprising: 
 a) contacting a light lube stream in a first solvent extraction zone with a first extraction solvent to produce at least a first aromatics-rich extract solution and a first aromatics-lean raffinate solution;    b) removing at least a portion of said first extraction solvent from said first aromatics-rich extract solution to produce at least a first aromatics-rich extract;    c) mixing at least a portion of said first aromatics-rich extract with a heavier lube stream to produce a mixed lube stream;    d) contacting said mixed lube stream in a second solvent-extraction zone with a second extraction solvent to produce at least a second aromatics-rich extract solution and a second aromatics-lean raffinate solution;    e) removing at least a portion of said second extraction solvent from said second aromatics-lean raffinate solution to produce at least a second aromatics-lean raffinate; and    f) dewaxing said second aromatics-lean raffinate to produce at least one base oil.    
     
     
         2 . The process of  claim 1  wherein said light lube stream is characterized as having a mid boiling point range of about 350° C. to about 450° C.  
     
     
         3 . The process according to  claim 2  wherein said heavier lube stream has a mid boiling point range greater than 450° C.  
     
     
         4 . The process of  claim 3  wherein said light lube stream is a hydrocracked light lube stream.  
     
     
         5 . The process of  claim 4  wherein said first extraction solvent and said second extraction solvent are selected from the group consisting of sulfolane, furfural, phenol, and N-methyl pyrrolidone (NMP).  
     
     
         6 . The process of  claim 5  wherein at least about 5 volume percent of said first aromatics-rich extract is conducted to said mixing zone.  
     
     
         7 . The process of  claim 6  wherein at least about 25 volume percent of said first aromatics-rich extract is conducted to said mixing zone.  
     
     
         8 . The process of  claim 7  wherein at least about 35 volume percent of said first aromatics-rich extract is conducted to said mixing zone.  
     
     
         9 . The process according to  claim 8  wherein the mixed lube stream comprises less than about 70 volume percent, based on the mixed lube stream, of the first aromatics-rich extract.  
     
     
         10 . The process according to  claim 9  wherein the mixed lube stream comprises less than about 30 volume percent, based on the mixed lube stream, of the first aromatics-rich extract.  
     
     
         11 . The process according to  claim 10  wherein the mixed lube stream comprises about 15 volume percent, based on the mixed lube stream, of the first aromatics-rich extract.  
     
     
         12 . The process of  claim 5  wherein said second aromatics-lean raffinate is dewaxed in a catalytic dewaxing zone.  
     
     
         13 . The process according to  claim 5  wherein said second aromatic-lean raffinate is dewaxed in a solvent dewaxing zone.  
     
     
         14 . The process of  claim 13  wherein said at least one base oil is characterized as having a mid-boiling point range (50% LV), as determined by ASTM D6417, of about 400 to about 490° C., and a Viscosity Index of about 80-120.  
     
     
         15 . The base oil of  claim 14 .  
     
     
         16 . The process of  claim 13  wherein said heavier lube stream is a hydrocracked heavier lube stream.  
     
     
         17 . A process to improve dewaxing performance and extraction yields of a lube boiling range stream comprising: 
 a) contacting at least one light lube stream in a first solvent extraction zone with a first extraction solvent to produce at least a first aromatics-rich extract solution and a first aromatics-lean raffinate solution;    b) removing at least a portion of said first extraction solvent from said first aromatics-rich extract solution to produce at least a first aromatics-rich extract;    c) contacting at least one other light lube stream in a second solvent extraction zone with a second extraction solvent to produce at least a second aromatics-rich extract solution and at least a second aromatics-lean raffinate solution;    d) removing at least a portion of said second extraction solvent from said second aromatics-rich extract solution to produce at least a second aromatics-rich extract;    e) mixing at least a portion of said first aromatics-rich extract and at least a portion of said second aromatics-rich extract with a heavier lube stream to produce a mixed lube stream;    f) contacting said mixed lube stream in a solvent-extraction zone with a third extraction solvent to produce at least a third aromatics-rich extract solution and at least a third aromatics-lean raffinate solution;    g) removing at least a portion of said third extraction solvent from said third aromatics-lean raffinate solution to produce at least a first aromatics-lean raffinate;    h) dewaxing said third aromatics-lean raffinate to produce at least one base oil.    
     
     
         18 . The process according to  claim 17  wherein said at least one light lube stream is a hydrocracked light lube stream and said at least one other light lube stream is a hydrocracked light lube stream.  
     
     
         19 . The process according to  claim 18  wherein said third aromatics-lean raffinate is dewaxed in said dewaxing zone by the use of solvent dewaxing methods or processes.  
     
     
         20 . The process according to  claim 19  wherein there exists more than two light lube streams that are hydrocracked light lube streams, hydrotreated light lube streams, or any combination thereof.  
     
     
         21 . The process according to  claim 20  wherein said heavier lube stream is a heavier hydrocracked lube stream.  
     
     
         22 . The process according to  claim 20  wherein said first aromatics-lean extract and said second aromatics-lean extract are mixed prior to being mixed in the mixing zone with the heavier lube stream.  
     
     
         23 . The product according to  claim 18.