Process to prepare a lubricating base oil and its use

Abstract

Lube base stocks and lube stock compositions, as well as a process for preparing lube base stocks and lube stock compositions, are disclosed. The lube oils preferably have a viscosity index above about 115. The process involves obtaining feed-stocks that have a 95% point below 1150° F. and feedstocks that have 95% point above 1150° F. The feedstocks that have a 95% point below 1150% are catalytically dewaxed, and the feedstocks that have 95% point above 1150% are solvent dewaxed. The resulting products can optionally be blended, and the base stocks can be combined with various additives to form lube oil compositions. Hydrotreatment can optionally be performed on the lube base stocks to remove olefins, oxygenates and other impurities. In one embodiment, one or more of the fractions are obtained from Fisher-Tropsch synthesis. One or more of the fractions can also be obtained from other sources, for example, via distillation of crude oil, provided that the fractions do not include appreciable amounts (i.e., amounts which would adversely affect the catalyst used for catalytic isodewaxing) of thiols or amines. The individual fractions can also includes combinations of feedstocks, from Fisher-Tropsch and other sources.

1 . A process for preparing lube base stocks, the process comprising:
 a) obtaining a first fraction with a 95% point above 1150° F. as measured by ASTM D2887 and a second fraction with a 95% point below 1150° F. as measured by ASTM D2887;   b) subjecting the first fraction to Solvent Dewaxing conditions to obtain a lube base stock with a VI of greater than or equal to 115; and   c) subjecting the second fraction to Catalytic Dewaxing conditions to obtain a lube base stocks having a viscosity less than the viscosity of the lube base stock of step b).   
   
   
       2 . The process of  claim 1  further comprising hydrotreating and dewaxing at least one of the factions selected from the group consisting of: hydrotreating followed by dewaxing, dewaxing followed by hydrotreating, and combinations thereof. 
   
   
       3 . The process of  claim 1  further comprising Catalytic Dewaxing and Solvent Dewaxing the first fraction selected from the group consisting of: Solvent Dewaxing followed by Catalytic Dewaxing, and Catalytic Dewaxing followed by Solvent Dewaxing. 
   
   
       4 . The process of  claim 3 , wherein the Catalytic Dewaxing process is a Hydroisomerization Dewaxing process. 
   
   
       5 . The process of  claim 4 , wherein the Hydroisomerization Dewaxing process is a Complete Hydroisomerization Dewaxing process. 
   
   
       6 . The process of  claim 1 , wherein the Catalytic Dewaxing process is a Hydroisomerization Dewaxing process. 
   
   
       7 . The process of  claim 6 , wherein the Hydroisomerization dewaxing process is a complete Hydroisomerization Dewaxing process. 
   
   
       8 . The process of  claim 1 , wherein at least a portion of one of the first and second fractions is derived the group consisting of Fischer-Tropsch synthesis products, slack wax from conventional petroleum lube production, distillates from crude oil, deasphalted residual stocks from crude oil, and combinations thereof. 
   
   
       9 . The process of  claim 8 , wherein at least a portion of one of the first and second fractions is derived from a Fischer-Tropsch synthesis products. 
   
   
       10 . The process of  claim 1 , wherein at least one the lube base stocks have a pour point/cloud point spread of less than 30° C. 
   
   
       11 . The process of  claim 1 , wherein the lube base stocks have a pour point/cloud point spread of less than 10° C. 
   
   
       12 . The process of  claim 1 , wherein the pour point of at least one of the lube base stocks is less than −10° C. 
   
   
       13 . The lube base stocks produced from the process according to  claim 1  having a pour point between −15 and −40° C., a VI above 115, a cloud point of less than −10° C., and a sulfur content of less than 300 ppm. 
   
   
       14 . The product according to  claim 13 , wherein at leas one of the lube base stocks are combined with one or more lube oil additives selected from the group consisting of lubricity improvers, emulsifiers, wetting agents, densifiers, fluid-loss additives, viscosity modifiers, corrosion inhibitors, oxidation inhibitors, friction modifiers, demulsifiers, anti-wear agents, dispersants, anti-foaming agents, pour point depressants, detergents, and rust inhibitors. 
   
   
       15 . The process of  claim 1 , wherein at least one of lube base stocks are combined with one or more lube oil additives selected from the group consisting of lubricity improvers, emulsifiers, wetting agents, densifiers, fluid-loss additives, viscosity modifiers, corrosion inhibitors, oxidation inhibitors, friction modifiers, demulsifiers, anti-wear agents, dispersants, anti-foaming agents, pour point depressants, detergents, and rust inhibitors. 
   
   
       16 . A lube base stock composition prepared by:
 a) obtaining a first fraction with a 95% point above 1150° F. and a second fraction with a 95% point below 1150° F.,   b) subjecting the first fraction to Solvent Dewaxing conditions, and   c) subjecting the second fraction to Catalytic Dewaxing conditions,   whereby the compositions of step b) and c) have a pour point between −15 and −40° C., a VI above 115, a cloud point of less than −10° C., and a sulfur content of less than 300 ppm.   
   
   
       17 . The compositions of  claim 16 , further comprising one or more lube oil additives selected from the group consisting of lubricity improvers, emulsifiers, wetting agents, densifiers, fluid-loss additives, viscosity modifiers, corrosion inhibitors, oxidation inhibitors, friction modifiers, demulsifiers, anti-wear agents, dispersants, anti-foaming agents, pour point depressants, detergents, and rust inhibitors. 
   
   
       18 . A lube base stock composition comprising a blend of a first fraction comprising a hydrocarbon stream prepared by Solvent Dewaxing a hydrocarbon fraction with a 95% point above 1150° F. and a second fraction comprising a hydrocarbon stream prepared by Catalytic Dewaxing a hydrocarbon fraction with a 95% point below 1150° F. 
   
   
       19 . The lube base stock composition of claim  23 , further comprising one or more lube oil additives selected from the group consisting of lubricity improvers, emulsifiers, wetting agents, densifiers, fluid-loss additives, viscosity modifiers, corrosion inhibitors, oxidation inhibitors, friction modifiers, demulsifiers, anti-wear agents, dispersants, anti-foaming agents, pour point depressants, detergents, and rust inhibitors. 
   
   
       20 . A process for preparing lube base stocks, having pour cloud spreads less than 30° C., the process comprising:
 a) fractionating a lube base stock feedstock into at least a heavier and a lighter fraction;   b) catalytically dewaxing the fractions using a Hydroisomerization Dewaxing Catalyst;   c) measuring the pour-cloud spread on the dewaxed lube base stocks from the fractions; and   d) modifying the process to achieve lube base stocks having pour cloud spreads of less than 30° C. from the process steps selected from the group consisting of adjusting the fractionation cut point, adjusting the fractionation efficiency, an additional process step of Solvent Dewaxing the lube base stocks, an additional process step of adsorbent treating the lube base stocks and combinations thereof, whereby the lube base stocks have a pour point between −15 and −40° C., a VI above 115, a cloud point of less than −10° C., and a sulfur content of less than 300 ppm.