Method for producing feedstocks of high quality lube base oil from unconverted oil

Abstract

The present invention relates to a method of producing a feedstock for high-quality lube base oil from unconverted oil (UCO) obtained from fuel oil hydrocracking, and more particularly to a method of producing a feedstock for high-quality lube base oil by treating vacuum gas oil (VGO) or a mixture of vacuum gas oil (VGO) with coker gas oil (CGO) or deasphalted oil (NAO) as a feedstock in a hydrotreating unit and a first hydrocracking unit and recycling the resulting unconverted oil (UCO) through a second hydrocracking unit.

1 . A method of producing a feedstock for high-quality lube base oil from unconverted oil, the method comprising:
 distilling atmospheric residue (AR) in a first vacuum distillation process (V1) to obtain vacuum gas oil (VGO), and feeding the vacuum gas oil (VGO) into a hydrotreating unit (HDT);   removing impurities from the vacuum gas oil through the hydrotreating unit (HDT);   obtaining light and heavy hydrocarbons from the vacuum gas oil through a first hydrocracking unit (HDC1);   feeding the light and heavy hydrocarbons into fractionators (Fs) to separate the hydrocarbons into oil products and unconverted oil;   feeding a portion of the separated unconverted oil into a second vacuum distillation unit (V2) to obtain a feedstock for high-quality lube base oil, having a given viscosity grade, and the remaining unconverted oil;   feeding the remaining unconverted oil separated from the fractionators (Fs) and the unconverted oil obtained from the second vacuum distillation unit (V2 ) into a second hydrocracking unit (HDC 2); and   recycling light and heavy hydrocarbons, obtained through the second hydrocracking process (HDC2), to the fractionators (Fs).   
   
   
       2 . A method for producing a feedstock for high-quality lube base oil from unconverted oil, the method comprising:
 distilling atmospheric residue (AR) in a first vacuum distillation process (V1) to separate it into vacuum gas oil (VGO) and vacuum residue (VR) or a mixture of atmospheric residue (AR) with vacuum residue (VR), feeding the vacuum gas oil (VGO) directly into a hydrotreating (HDT) unit, feeding the vacuum residue (VR) or the vacuum residue/atmospheric residue mixture (VR/AR) through fractionators (Fs′) to coker drums to subject it to a coking process and passing the coked residue through fractionators (Fs′) to obtain coker gas oil, and feeding the obtained coker gas oil together with the vacuum gas oil (VGO) into a hydrotreating (HDT) unit;   removing impurities from the vacuum gas oil and the coker gas oil through the hydrotreating (HDT) unit;   obtaining light and heavy hydrocarbons from the vacuum gas oil through a first hydrocracking (HDC1) unit;   feeding the light and heavy hydrocarbons into fractionators (Fs) to separate the hydrocarbons into oil products and unconverted oil;   feeding a portion of the unconverted oil to a second vacuum distillation unit (V2) to obtain a feedstock for high-quality lube base oil, having a given viscosity grade, and the remaining unconverted oil;   feeding the remaining unconverted oil, separated from the fractionators, and the unconverted oil, obtained from the second vacuum distillation unit (V2), into a second hydrocracking unit (HDC2); and   recycling light and heavy hydrocarbons, obtained through the second hydrocracking unit (HDC2), to the fractionators (Fs).   
   
   
       3 . A feedstock of producing a feedstock for high-quality lube base oil from unconverted oil, the method comprising:
 distilling atmospheric residue in a first vacuum distillation unit (V1) to separate it into vacuum gas oil (VGO) and vacuum residue (VR), feeding the vacuum gas oil (VGO) directly into a hydrotreating unit (HDT), feeding the vacuum residue into a solvent deasphalting unit (SDA) to obtain deasphalted oil (DAO) from which asphalt and impurities have been removed, and feeding the deasphalted oil (DAO) together with the vacuum gas oil (VGO) into the hydrotreating unit (HDT);   removing impurities from the vacuum gas oil and the deasphalted oil through the hydrotreating unit (HDT);   obtaining light and heavy hydrocarbons from the vacuum gas oil and the deasphalted oil through a first hydrocracking unit (HDC1);   feeding the light and heavy hydrocarbons into fractionators (Fs) to separate the hydrocarbons into oil products and unconverted oil;   feeding a portion of the separated unconverted oil into a second vacuum distillation unit (V2) to obtain a feedstock for high-quality lube base oil, having a given viscosity grade, and the remaining unconverted oil;   feeding the remaining unconverted oil, separated from the fractionators, and the unconverted oil, obtained from the second vacuum distillation unit (V2), into a second hydrocracking unit (HDC2); and   recycling light and heavy hydrocarbons, obtained through the second hydrocracking unit (HDC2), to the fractionators (Fs).   
   
   
       4 . The method of  claim 2 , wherein the mixing volume ratio (VGO/CGO) between the vacuum gas oil (VGO) and the coker gas oil (CGO), which are fed into the hydrotreating unit (HDT), is 2-9. 
   
   
       5 . The method of  claim 3 , wherein the mixing volume ratio (VGO/DAO) between the vacuum gas oil (VGO) and the deasphalted oil (DAO), which are fed into the hydrotreating unit (HDT), is 2-9. 
   
   
       6 . The method of  claim 1 , wherein the ratio of the unconverted oil fed into the second hydrocracking unit HDC2 to the unconverted oil produced in the fractionators Fs is 1:2-1:5. 
   
   
       7 . The method of  claim 2 , wherein the ratio of the unconverted oil fed into the second hydrocracking unit HDC2 to the unconverted oil produced in the fractionators Fs is 1:2-1:5. 
   
   
       8 . The method of  claim 3 , wherein the ratio of the unconverted oil fed into the second hydrocracking unit HDC2 to the unconverted oil produced in the fractionators Fs is 1:2-1:5. 
   
   
       9 . The method of  claim 1 , wherein the ratio of the unconverted oil fed from the second vacuum distillation unit (V2) into the second hydrocracking unit HDC2 to the unconverted oil fed into the second vacuum distillation unit V2 is 1:1.2-1:1.5. 
   
   
       10 . The method of  claim 2 , wherein the ratio of the unconverted oil fed from the second vacuum distillation unit (V2) into the second hydrocracking unit HDC2 to the unconverted oil fed into the second vacuum distillation unit V2 is 1:1.2-1:1.5. 
   
   
       11 . The method of  claim 3 , wherein the ratio of the unconverted oil fed from the second vacuum distillation unit (V2) into the second hydrocracking unit HDC2 to the unconverted oil fed into the second vacuum distillation unit V2 is 1:1.2-1:1.5.