Method for the reduction of deposits in jet engine

Abstract

A method for reducing the level of deposits in a jet engine, the method comprising supplying to the engine a jet fuel composition comprising a jet fuel and at least one hydrocarbyl comb polymer. The at least one hydrocarbyl comb polymer has a number average molecular weight of less than 5,500, preferably less than 5,000.

1 . A method for reducing the level of deposits in a jet engine, the method comprising supplying to the jet engine a fuel composition including a jet fuel and at least one hydrocarbyl comb polymer having a number average molecular weight of less than 5,500.  
     
     
         2 . The method according to  claim 1  in which the hydrocarbyl comb polymer has a number average molecular weight of less than 4,500.  
     
     
         3 . The method of  claim 1  in which the hydrocarbyl comb polymer is a hydrocarbon polymer or copolymer of a C 3 -C 9  1-alkene and a C 10 -C 14  1-alkene.  
     
     
         4 . The method of  claim 1  in which the hydrocarbyl comb polymer is a hydrocarbon polymer or copolymer of a C 6 -C 8  1-alkene and a C 12  1-alkene.  
     
     
         5 . The method of  claim 1  in which the hydrocarbyl comb polymer is a hydrocarbon polymer or copolymer of a C 8  1-alkene and a C 12  1-alkene.  
     
     
         6 . The method of  claim 1  in which the jet fuel also includes at least one of the following: 
 a copolymer of ethylene and at least one unsaturated ester;    a copolymer of ethylene and alkene;    a nucleator;    a wax;    a substantially branched alkyl phenol formaldehyde condensate;    a comb polymer selected from a polymer or copolymer of an unsaturated ester or an olefin maleic anhydride copolymer; or    a polar nitrogen compound.    
     
     
         7 . The method of  claim 1  in which the at least one hydrocarbyl comb polymer is present in the fuel composition in an amount ranging from 10 to 20,000 ppm.  
     
     
         8 . The method of  claim 1  in which the pour point of the fuel composition is less than the pour point of the jet fuel.  
     
     
         9 . A process for reducing the level of deposits in a jet engine supplied with a fuel formulation, which process includes blending a jet fuel and at least one hydrocarbyl comb polymer having a number average molecular weight of less than 5,500 to produce the fuel formulation.  
     
     
         10 . A fuel composition comprising a jet fuel and at least one hydrocarbyl comb polymer, in which fuel composition the at least one hydrocarbyl comb polymer is a hydrocarbon polymer or copolymer of a C 8  1-alkene and a C 12  1-alkene, and has a number average molecular weight of less than 5,500.  
     
     
         11 . The fuel composition of  claim 10 , in which the hydrocarbon polymer or copolymer has a number average molecular weight of less than 4,500.  
     
     
         12 . The fuel composition according to  claim 10 , which also includes at least one of the following: 
 a copolymer of ethylene and at least one unsaturated ester;    a copolymer of ethylene and alkene;    a nucleator;    a wax;    a substantially branched alkyl phenol formaldehyde condensate;    a comb polymer selected from a polymer or copolymer of an unsaturated ester or an olefin maleic anhydride copolymer; or    a polar nitrogen compound.    
     
     
         13 . The fuel composition of  claim 10  in which the proportion of the hydrocarbon polymer or copolymer to the composition is in the range of 10 to 20,000 ppm.  
     
     
         14 . A process for reducing the pour point of a jet fuel, the process including the following steps: 
 providing a jet fuel; and,    adding to the jet fuel at least one hydrocarbyl comb polymer;    wherein the at least one hydrocarbyl comb polymer is a hydrocarbon polymer or copolymer of a C 8  1-alkene and a C 12  1-alkene, and has a number average molecular weight of less than 5,500.    
     
     
         15 . A process for enhancing the low temperature operability of a jet fuel, which process comprises: 
 blending at least one hydrocarbyl comb polymer with the jet fuel;    wherein the at least one hydrocarbyl comb polymer is a hydrocarbon polymer or copolymer of a C 8  1-alkene and a C 12  1-alkene, and has a number average molecular weight of less than 5,500, preferably less than 5,000.