Aviation fuel cold flow additives and compositions

Abstract

Aviation fuel, such as jet fuel, blends and methods for improving cold flow properties of such fuels at extremely low temperatures are disclosed. Cold flow properties of, for example, JP-8 based jet fuels are improved by addition to the fuel of a variety of C 10 -C 16 alkyl poly(meth)acrylate esters and polyvinylesters of C 10 -C 16 alkanoic acids. Demonstratable cold flow improvement of such fuels at temperatures of about −53° C. and below is shown.

What is claimed is:  
     
         1 . Method of improving the cold flow rate of jet fuel comprising adding to said jet fuel an effective amount for the purpose of a polymeric cold flow rate enhancement agent (CFREA) having (a) repeat units characterized by the formula  
       
         
           
           
               
               
           
         
       
       wherein R 1  is hydrogen, CH 3 , or mixtures thereof; R 2  is —C(O)—O—, —O—(O)C—, —C(O)—NH—, or mixtures thereof; R 3  is C 10 -C 16  alkyl, or mixtures thereof, repeat units (b) from 0 to 5 mole percent of a branching agent, and (c) from 0 to 20 mole percent of a repeat unit resulting from free radical ring-opening polymerization of a cyclic monomer characterized by the formula  
       
         
           
           
               
               
           
         
       
       wherein R 4  is —O—, —S—, —N(CH 3 )—, —CH 2 — or mixtures thereof; and x is an integer from 1 to 3.  
     
     
         2 . Method as recited in  claim 1  comprising adding from a 1-7,500 mg of said CFREA to said jet fuel, based upon 1 liter of said jet fuel.  
     
     
         3 . Method as recited in  claim 1  wherein said jet fuel is a JP-8 based jet fuel.  
     
     
         4 . Method as recited in  claim 1  wherein said CFREA is a C 10 -C 16  alkyl poly(meth)acrylate ester.  
     
     
         5 . Method as recited in  claim 1  wherein said CFREA comprises a mixture of C 10 -C 16  alkyl poly(meth)acrylate esters.  
     
     
         6 . Method as recited in  claim 1  wherein said CFREA is a polyvinylester of a C 10 -C 16  carboxylic acid.  
     
     
         7 . Method as recited in  claim 5  wherein said CFREA is poly(vinyldecanoate).  
     
     
         8 . Method as recited in  claim 4  wherein said CFREA is polylauryl(meth)acrylate.  
     
     
         9 . Method as recited in  claim 4  wherein said CFREA is polydecylacrylate.  
     
     
         10 . Method as recited in  claim 4  wherein said CFREA is polytridecyl(meth)acrylate.  
     
     
         11 . Method as recited in  claim 1  further comprising adding, as an adjuvant treatment to said jet fuel about 1-7,500 mg/L of an oil-soluble, polar nitrogen compound to said jet fuel.  
     
     
         12 . Method as recited in  claim 11  wherein said oil-soluble, polar nitrogen compound comprises an amine salt or amide.  
     
     
         13 . Method as recited in  claim 12  wherein said oil-soluble polar nitrogen compound comprises a reaction product formed from reaction of a hydrocarbyl acid having two or more carboxyl groups, or anhydride thereof, and a hydrocarbyl secondary amine followed by neutralization of the resulting product with a hydrocarbyl primary amine.  
     
     
         14 . Method as recited in  claim 11  wherein said oil-soluble, polar nitrogen compound is benzoic acid, 2-[(bis(hydrogenated tallow alkyl)amino)carbonyl]-C 16 -C 22  tert-alkyl amine salt.  
     
     
         15 . Composition for improving the cold flow rate of jet fuel said composition comprising, in an organic solvent medium, 1) a polymeric cold flow rate enhancement agent (CFREA) having (a) repeat units characterized by the formula  
       
         
           
           
               
               
           
         
       
       wherein R 1  is hydrogen, CH 3 , or mixtures thereof; R 2  is —C(O)—O—, —O—(O)C—, —C(O)—NH—, or mixtures thereof; R 3  is C 10 -C 16  alkyl, or mixtures thereof, repeat units (b) from 0 to 5 mole percent of a branching agent, and repeat units (c) having from 0 to 20 mole percent of a repeat unit resulting from free radical ring-opening polymerzation of a cyclic monomer characterized by the formula  
       
         
           
           
               
               
           
         
       
       wherein R 4  is —O—, —S—, —N(CH 3 )—, —CH 2 — or mixtures thereof; and x is an integer from 1 to 3; and 2) an oil-soluble, polar, nitrogen-containing compound.  
     
     
         16 . Composition as recited in  claim 15  wherein 1) is present in an amount of about 0.01-100 moles of 1) per one mole of 2).  
     
     
         17 . Composition as recited in  claim 15  wherein said oil-soluble polar nitrogen-containing compound is an amine salt and/or amide.  
     
     
         18 . Composition as recited in  claim 17  wherein said oil-soluble, polar nitrogen-containing compound is a reaction product formed by reaction of a C 4 -C 24  hydrocarbyl acid or anhydride thereof with a C 4 -C 24  hydrocarbyl substituted primary, secondary, and/or tertiary amine.  
     
     
         19 . Composition as recited in  claim 18  wherein said oil-soluble, polar nitrogen containing compound comprises a reaction product formed from reaction of a hydrocarbyl acid having two or more carboxyl groups or an anhydride thereof and a hydrocarbyl secondary amine followed by neutralization of the resulting product with a hydrocarbyl primary amine.  
     
     
         20 . Compositions as recited in  claim 15  wherein said oil-soluble, polar nitrogen compound is benzoic acid 2-[(bis(hydrogenated tallow alkyl) amino)carbonyl]C 16 -C 22  tert-alkyl amine salt.  
     
     
         21 . Composition as recited in  claim 19  wherein said CFREA is polylauryl(meth)acrylate.  
     
     
         22 . Composition as recited in  claim 20  wherein said CFREA is polylauryl(meth)acrylate.