Process to Make a Base Oil

Abstract

Process to prepare a base oil having a kinematic viscosity at 100° C. of greater than 6 cSt from a Fischer-Tropsch derived wax having a T10wt % recovery boiling point of above 500° C. by performing the following steps, (a) contacting a feed comprising the Fischer-Tropsch wax and between 5 and 40 wt % of a hydrocarbon diluent having a T90wt % recovery point of below 400° C. with a hydro-isomerisation catalyst under hydro-isomerisation, and (b) dewaxing the isomerised product of step (a) and isolating the base oil from the dewaxed oil obtained in step (b).

1 . A process to prepare a base oil having a kinematic viscosity at 100° C. of greater than 6 cSt from a Fischer-Tropsch derived wax having a T10wt % recovery boiling point of above 500° C. comprising: 
 (a1) performing a Fischer-Tropsch synthesis to prepare a Fischer-Tropsch synthesis product;    (a2) isolating, by means of distillation, from said Fischer-Tropsch synthesis product a Fischer-Tropsch wax, an intermediate wax product boiling for more than 80 wt % between 300 and 500° C., and a hydrocarbon diluent having a T90 wt % recovery point of below 400° C.; and    (a3) combining the Fischer-Tropsch wax and the diluent to form a feed to step (a); 
 (a) contacting the feed comprising the Fischer-Tropsch wax and between 5 and 40 wt % of a hydrocarbon diluent having a T90 wt % recovery point of below 400° C. with a hydro-isomerisation catalyst under hydro-isomerisation conditions,  
 (b) dewaxing isomerised product of step (a) and isolating a base oil from the dewaxed oil.  
   
   
   
       2 . The process according to  claim 1 , wherein the content of the Fischer-Tropsch wax in the feed to step (a) is greater than 70 wt %.  
   
   
       3 . The process according to  claim 1 , wherein the diluent is Fischer-Tropsch derived product.  
   
   
       4 . The process according to  claim 1 , wherein the T10wt % recovery point of the diluent is between 250 and 370° C.  
   
   
       5 . The process according to  claim 1 , wherein the isomerisation catalyst used in step (b) comprises nickel, platinum or palladium.  
   
   
       6 . The process according to  claim 5 , wherein in step (a) a catalyst is used comprising a silica-alumina carrier and in step (b) a dewaxing catalyst is used comprising platinum or palladium and ZSM-48 and wherein steps (a) and (b) are performed in series flow.  
   
   
       7 . The process according to  claim 1 , wherein the base oil obtained by the process has a kinematic viscosity at 100° C. of greater than 8 cSt, a viscosity index of greater than 140 and a Noack volatility of below 7 wt %.  
   
   
       8 . The process according to  claim 1 , wherein the feed to step (a) is prepared by performing a Fischer-Tropsch synthesis to prepare a Fischer-Tropsch synthesis product, isolating, by means of distillation, from said Fischer-Tropsch synthesis product a Fischer-Tropsch wax, an intermediate wax product boiling for more than 80 wt % between 300 and 500° C. and a diluent, combining the Fischer-Tropsch wax and the diluent to form a feed to step (a) and keeping separate from the feed to step (a) the intermediate wax product.