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 jet fuel are improved by addition to the fuel of an oil-soluble, polar nitrogen-containing compound. Demonstratable cold flow improvement of such fuels at temperatures of about −53° C. and lower is shown.

1 . Method of improving the cold flow rate of jet fuel comprising adding to said jet fuel an effective amount of the purpose of a cold flow rate enhancement agent (CFREA) comprising an oil-soluble, polar, nitrogen-containing compound.  
   
   
       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 oil-soluble, polar nitrogen compound comprises an amine salt or amide.  
   
   
       5 . Method as recited in  claim 4 , 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.  
   
   
       6 . Method as recited in  claim 1  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.  
   
   
       7 . Method as recited in  claim 2  wherein said oil-soluble, polar nitrogen-containing compound is represented by the formula  
     
       
         
         
             
             
         
       
     
     wherein Z is a divalent organic radical, and R 1 , R 2 , and R 3  are independently chosen from C 10 -C 40  hydrocarbyl groups.  
   
   
       8 . Method as recited in  claim 2  wherein said oil-soluble, polar, nitrogen-containing compound is formed from a reaction of a hydrocarbyl acid having from about 1 to about 4 carboxyl groups or anhydrides thereof with a hydrocarbyl substituted primary, secondary, or tertiary amine.  
   
   
       9 . Method as recited in  claim 8  wherein said hydrocarbyl acid or anhydride and hydrocarbyl substituted primary, secondary, and tertiary amines each have from about 4 to about 24 carbon atoms.  
   
   
       10 . Method as recited in  claim 9  wherein said hydrocarbyl acid or anhydride and hydrocarbyl substituted primary, secondary, and tertiary amines each have from about 10-24 carbon atoms.  
   
   
       11 . Method as recited in  claim 3  wherein said JP-8 jet fuel is subjected to temperatures of −53.0° C. and lower.