Method of recycling waste lubricant

Abstract

A method of recycling waste lubricant, the method including providing a waste lubricant-derived oil fraction, pretreating the waste lubricant-derived oil fraction, and hydrocracking the pretreated waste lubricant-derived oil fraction. The method recycles waste lubricant into fuel oil and high-grade lube base oil. According to the above method, high-quality lubricating base oil can be produced from waste lubricating oil, which is advantageous in economic terms.

What is claimed is: 
     
         1 . A method of recycling waste lubricant, the method comprising:
 providing a waste lubricant-derived oil fraction;   pretreating the waste lubricant-derived oil fraction; and   hydrocracking the pretreated waste lubricant-derived oil fraction.   
     
     
         2 . The method of  claim 1 , wherein the waste lubricant-derived oil fraction has a kinematic viscosity at 40° C. in a range of 20 to 60 cSt and a pour point of lower than 0° C. 
     
     
         3 . The method of  claim 1 , wherein the pretreating comprises performing solvent extraction on the waste lubricant-derived oil fraction. 
     
     
         4 . The method of  claim 1 , further comprising a first blending operation of blending the waste lubricant-derived oil fraction with a hydrocarbon feedstock to produce a first formulation, prior to the hydrocracking. 
     
     
         5 . The method of  claim 4 , wherein the first formulation comprises 1% to 10% by volume of the waste lubricant-derived oil fraction with respect to the total volume thereof. 
     
     
         6 . The method of  claim 1 , wherein the method further comprises recovering a plurality of fractions including a first fraction and a second fraction, from the product of the hydrocracking. 
     
     
         7 . The method of  claim 6 , wherein the first fraction has a boiling point in a range of boiling point of fuel oil. 
     
     
         8 . The method of  claim 6 , wherein the second fraction has a boiling point higher than the boiling point of the first fraction. 
     
     
         9 . The method of  claim 6 , further comprising a second blending operation of blending the second fraction with a separate waste lubricant-derived oil fraction to produce a second formulation. 
     
     
         10 . The method of  claim 9 , wherein the separate waste lubricant-derived oil fraction used in the second blending is introduced in an amount of 3% to 50% by volume with respect to the volume of the second formulation. 
     
     
         11 . The method of  claim 9 , further comprising catalytically dewaxing the second formulation. 
     
     
         12 . The method of  claim 11 , further comprising:
 hydrofinishing the catalytically dewaxed second formulation; and   recovering the product of the hydrofinishing as a lube base oil.   
     
     
         13 . A method of recycling waste lubricant, the method comprising:
 providing a first waste lubricant-derived oil fraction;   blending the waste lubricant-derived oil fraction with a hydrocarbon feedstock to produce a first formulation;   pretreating the first formulation by subjecting the first formulation to a solvent extraction operation;   hydrocracking the pretreated first formulation;   recovering a first fraction and a second fraction from the hydrocracking operation;   blending the second fraction with a second waste lubricant-derived oil fraction to produce a second formulation;   catalytically dewaxing the second formulation, and   hydrofinishing the dewaxed second formulation to produce a lube base oil.   
     
     
         14 . The method of  claim 13 , wherein the first waste lubricant-derived oil fraction has a kinematic viscosity at 40° C. in a range of 20 to 60 cSt and a pour point of −21° C. to 0° C. 
     
     
         15 . The method of  claim 14 , wherein the waste lubricant-derived oil fraction is a refined oil fraction from a process in which waste lubricant undergoes at least one of a centrifugal separation, atmospheric distillation, vacuum distillation, or any combination thereof, and
 wherein the refined oil fraction has a sulfur content of less than 200 ppm, a nitrogen content of less than 100 ppm, and a chlorine content of less than 2000 ppm.