Fischer tropsch derived diesel fuel formulation

Abstract

A method of operating a diesel fuel-consuming system, and/or apparatus which is driven by such a system, the method comprising introducing into the system a diesel fuel formulation containing 10% v/v or more of paraffinic hydrocarbons and an antioxidant and a species selected from: (iii) detergents; (iv) mixtures containing both a lubricity improver and a conductivity improver; and (v) combinations of (i) and (ii). The methods results in an increase in the oxidative stability of the formulation and/or in a reduction of the concentration of an antioxidant which is present in the formulation. The formulation may comprise a Fischer-Tropsch derived diesel fuel component or mixture thereof.

We claim: 
     
         1 . A method of operating a diesel fuel-consuming system, and/or apparatus which is driven by such a system, the method comprising introducing into the system a diesel fuel formulation containing 10% v/v or more of paraffinic hydrocarbons and an antioxidant and a species selected from:
 (i) detergents;   (ii) mixtures containing both a lubricity improver and a conductivity improver; and   (iii) combinations of (i) and (ii).   
     
     
         2 . The method of  claim 1 , wherein the antioxidant is selected from phenolic antioxidants, in particular hindered phenols; amines, in particular aromatic amines; and mixtures thereof. 
     
     
         2 . The method of  claim 1 , wherein the antioxidant is selected from amines, in particular aromatic amines, and mixtures thereof. 
     
     
         3 . The method of  claim 1 , wherein the diesel fuel formulation contains 25% v/v or greater of a Fischer-Tropsch derived diesel fuel component. 
     
     
         4 . The method of  claim 2 , wherein the diesel fuel formulation contains 25% v/v or greater of a Fischer-Tropsch derived diesel fuel component. 
     
     
         5 . The method of  claim 3 , wherein the diesel fuel formulation contains 25% v/v or greater of a Fischer-Tropsch derived diesel fuel component. 
     
     
         6 . The method of  claim 1 , wherein the diesel fuel formulation contains 60% v/v or more of paraffinic hydrocarbons. 
     
     
         7 . The method of  claim 2 , wherein the diesel fuel formulation contains 60% v/v or more of paraffinic hydrocarbons. 
     
     
         8 . The method of  claim 3 , wherein the diesel fuel formulation contains 60% v/v or more of paraffinic hydrocarbons. 
     
     
         9 . The method of  claim 1 , wherein species (i) or (iii) comprises a nitrogen-containing detergent, in particular an amine- or polyamine-containing detergent, for example a polyisobutenyl (PIB) succinimide. 
     
     
         10 . The method of  claim 2 , wherein species (i) or (iii) comprises a nitrogen-containing detergent, in particular an amine- or polyamine-containing detergent, for example a polyisobutenyl (PIB) succinimide. 
     
     
         11 . The method of  claim 3 , wherein species (i) or (iii) comprises a nitrogen-containing detergent, in particular an amine- or polyamine-containing detergent, for example a polyisobutenyl (PIB) succinimide. 
     
     
         12 . The method of  claim 1 , wherein species (ii) or (iii) comprises an ester-based lubricity improver, in particular a fatty acid ester. 
     
     
         13 . The method of  claim 2 , wherein species (ii) or (iii) comprises an ester-based lubricity improver, in particular a fatty acid ester. 
     
     
         14 . The method of  claim 3 , wherein species (ii) or (iii) comprises an ester-based lubricity improver, in particular a fatty acid ester. 
     
     
         15 . The method of  claim 1 , wherein species (ii) or (iii) comprises a sulphonic acid conductivity improver, in particular a naphthyl sulphonic acid conductivity improver. 
     
     
         16 . The method of  claim 2 , wherein species (ii) or (iii) comprises a sulphonic acid conductivity improver, in particular a naphthyl sulphonic acid conductivity improver. 
     
     
         17 . The method of  claim 3 , wherein species (ii) or (iii) comprises a sulphonic acid conductivity improver, in particular a naphthyl sulphonic acid conductivity improver. 
     
     
         18 . A method of operating a diesel fuel-consuming system and/or apparatus which is driven by such a system, the method comprising introducing into the system a diesel fuel additive composition containing an antioxidant and a species selected from:
 (i) detergents;   (ii) mixtures containing both a lubricity improver and a conductivity improver; and   (iii) combinations of (i) and (ii).   
     
     
         19 . A method for preparing a diesel fuel formulation, the method comprising the steps of: (a) providing a diesel fuel component or mixture thereof, which contains 10% v/v or greater of paraffinic hydrocarbons and also an antioxidant; (b) optionally assessing the oxidative stability of the component or mixture; (c) adding to the component or mixture a species selected from:
 (i) detergents;   (ii) mixtures containing both a lubricity improver and a conductivity improver; and   (iii) combinations of (i) and (ii), and (d) assessing the oxidative stability of the resultant formulation.