Process to Prepare a Lubricating Base Oil

Abstract

Process to prepare a base oil having an paraffin content of between 75 and 95 wt % by subjecting a mixture of a Fischer-Tropsch derived feed and a gas field condensate derived feed to a catalytic pour point reducing treatment.

1 . A process to prepare a base oil having a paraffin content of between 75 and 95 wt % comprising subjecting a mixture of a Fischer-Tropsch derived feed and a gas field condensate derived feed to a catalytic pour point reducing treatment, wherein the gas field condensate has an aromatic content of between 0 and 20 wt % and a naphthenic compound content of between 15 and 90 wt %.  
     
     
         2 . The process according to  claim 1 , wherein the content of sulphur in the mixture subjected to the pour point reducing treatment is below 50 ppm and the content of nitrogen in the mixture subjected to the pour point reducing treatment is below 10 ppm.  
     
     
         3 . The process according to  claim 1 , wherein the fraction of gas field condensate in the mixture is higher than 5 wt % and lower than 50 wt %.  
     
     
         4 . The process according to  claim 1 , wherein the base oil is hydrogenated after performing the pour point reducing treatment such that the content of aromatics is below 1 wt %.  
     
     
         5 . The process according to  claim 1 , wherein the catalytic pour point reducing treatment is a catalytic dewaxing process performed in the presence of a catalyst comprising a Group VIII metal and an intermediate pore size zeolite having pore diameter between 0.35 and 0.8 nm, and a binder.  
     
     
         6 . The process according to  claim 1 , wherein after performing the catalytic pour point reducing treatment hydrogen is separated from the dewaxed effluent, contacted with a heterogeneous adsorbent selective for removing hydrogen sulphide and recycled to said catalytic pour point reducing treatment.  
     
     
         7 . The process according to  claim 6 , wherein the heterogeneous adsorbent is zinc oxide.  
     
     
         8 . The process according to  claim 1 , wherein the Fischer-Tropsch derived feed is obtained by hydroisomerisation of a Fischer-Tropsch product.  
     
     
         9 . The process according to  claim 1 , wherein the feed to the catalytic dewaxing step is obtained by hydroisomerisation of a mixture of a Fischer-Tropsch product and a gas field condensate.  
     
     
         10 . The process according to  claim 8 , wherein the hydroisomerised Fischer-Tropsch feed is obtained by means of the following steps: 
 (a) hydrocracking/hydroisomerisating a Fischer-Tropsch product,    (b) separating by means of distillation the product of step (a) into one or more gas oil fractions and a higher boiling Fischer-Tropsch derived feed.    
     
     
         11 . The process according to  claim 1 , wherein the Fischer-Tropsch product used as feed in step (a) is a product wherein the weight ratio of compounds having at least 60 or more carbon atoms and compounds having at least 30 carbon atoms in the Fischer-Tropsch product is at least 0.4 and wherein at least 30 wt % of compounds in the Fischer-Tropsch product have at least 30 carbon atoms.