Jet fuel compositions

Abstract

Jet fuel compositions having good low temperature operability. The jet fuel compositions comprise a jet fuel and at least one of the following additives: (i) a copolymer of ethylene and at least one unsaturated ester selected from: vinyl esters having at least 5 carbon atoms, alkyl (meth)acrylates, di-alkyl fumarates and di-alkyl maleates; (ii) a copolymer of ethylene and alkene; (iii) a copolymer of ethylene and less than 15 mole percent of vinyl acetate; (iv) a nucleator; (v) a wax; (vi) a substantially branched alkyl phenol formaldehyde condensate; (vii) a comb polymer; and (viii) a polar nitrogen compound.

1 . A jet fuel composition comprising a jet fuel and at least one of the following additives: 
 (i) a copolymer of ethylene and at least one unsaturated ester selected from the group consisting of vinyl esters having at least 5 carbon atoms, alkyl (meth)acrylates, di-alkyl fumarates and dialkyl maleates;    (ii) a copolymer of ethylene and alkene;    (iii) a copolymer of ethylene and less than 15 mole percent of vinyl acetate;    (iv) a nucleator;    (v) a wax;    (vi) a substantially branched alkyl phenol formaldehyde condensate;    (vii) a comb polymer; and    (viii) a polar nitrogen compound.    
     
     
         2 . The jet fuel composition as claimed in  claim 1 , comprising jet fuel and an additive combination of at least one copolymer selected from the group consisting of (i), (ii) or (iii), at least one polar nitrogen compound (viii) and optionally at least one nucleator (iv).  
     
     
         3 . The jet fuel composition as claimed in  claim 1 , comprising jet fuel and an additive combination of at least one copolymer selected from (i), (ii) or (iii), at least one comb polymer (vii) and optionally at least one nucleator (iv).  
     
     
         4 . The jet fuel composition as claimed in  claim 1 , comprising jet fuel and an additive combination of at least one polar nitrogen compound (viii) and at least one comb polymer (vii).  
     
     
         5 . The jet fuel composition as claimed in  claim 1 , comprising jet fuel and an additive combination of at least one polar nitrogen compound (viii) and at least one substantially branched alkyl phenol formaldehyde condensate (vi).  
     
     
         6 . The jet fuel composition as claimed in  claim 1 , comprising jet fuel and an additive combination of at least one polar nitrogen compound (viii) and at least one nucleator (iv).  
     
     
         7 . The jet fuel composition as claimed in claims  1 - 6 , wherein the additive or additive combination is present in the jet fuel composition in an amount ranging from 10 to 20,000 ppm (parts additive per million parts fuel).  
     
     
         8 . The jet fuel composition as claimed in claims  1 - 6 , wherein the jet fuel is selected from the group consisting of Jet A, Jet A-1, Jet B, MIL JP 5, MIL JP 7, MIL JP 8 and MIL JP 4.  
     
     
         9 . The jet fuel composition as claimed in  claim 1 , wherein the copolymer of ethylene and at least one unsaturated ester (i) is a copolymer of ethylene and at least one vinyl ester (i) having the formula:  
       —CR 1 R 2 —CHR 3    
       wherein R 2  represents hydrogen or a methyl group; R 1  represents a —OOCR 4  group wherein R 4  represents a C 1  to C 28  straight or branched chain alkyl group; R 3  represents hydrogen or alkyl; and the vinyl ester having at least 5 carbon atoms.  
     
     
         10 . The jet fuel composition as claimed in  claim 9 , wherein the vinyl ester is selected from the group consisting of vinyl propionate, vinyl butyrate, vinyl hexanoate, vinyl 2-ethylhexanoate, vinyl octanoate, vinyl benzoate and neo acid vinyl esters.  
     
     
         11 . The jet fuel composition as claimed in  claim 1 , wherein the copolymer of ethylene and at least one unsaturated ester (i) has a molar ethylene content of between 50 and 95 mole percent.  
     
     
         12 . The jet fuel composition as claimed in  claim 1 , wherein the copolymer of ethylene and alkene (ii) is a copolymer of ethylene and 1-alkene having at most 20 carbon atoms the 1-alkene being selected from the group consisting of propylene, 1-butene, 1-hexene, 1-octene, methyl-1-pentene, 1decene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1hexadecene, 1-octadecene, 1-eicosene and vinyl-cyclohexane and mixtures thereof.  
     
     
         13 . The jet fuel composition as claimed in  claim 1 , wherein the copolymer of ethylene and alkene (ii) has a molar ethylene content of between 50 and 90 mole percent.  
     
     
         14 . The jet fuel composition as claimed in  claim 1 , wherein the copolymer of ethylene and less than 15 mole percent of vinyl acetate (iii) includes less than 14 mole percent of vinyl acetate.  
     
     
         15 . The jet fuel composition as claimed in  claim 1 , wherein the nucleator (iv) is a polyoxyalkylene compound.  
     
     
         16 . The jet fuel composition as claimed in  claim 1 , wherein the nucleator (iv) is a block copolymer comprising a single crystallizable block and a single non-crystallizable block.  
     
     
         17 . The jet fuel composition as claimed in any  claim 1 , wherein the wax (v) includes normal and non-normal paraffin hydrocarbons.  
     
     
         18 . The jet fuel composition as claimed in  claim 1 , wherein the substantially branched alkyl phenol formaldehyde condensate (vi) is an iso-nonyl phenol formaldehyde condensate or an iso-dodecyl phenol formaldehyde condensate.  
     
     
         19 . The jet fuel composition as claimed in  claim 1 , wherein the comb polymer (vii) has the general formula:  
       
         
           
           
               
               
           
         
       
       where 
 D represents R 11 , COOR 10 , OCOR 10 , R 11 COOR 10  or R 10 ;  
 E represents H or D;  
 G represents H or D;  
 J represents H, R 11 , R 11 COOR 10 , or a substituted or unsubstituted aryl or heterocyclic group;  
 K represents H, COOR 11 , OCOR 11 , OR 11  or COOH;  
 L represents H, R 11 , COOR 11 , OCOR 11  or substituted or unsubstituted aryl;  
 R 10  representing a hydrocarbyl group having 10 or more carbon atoms, and  
 R 11  representing a hydrocarbylene (divalent) group in the R 11 COOR 10  moiety and otherwise a hydrocarbyl (monovalent) group,  
 and m and n represent mole ratios, their sum being 1 and m being finite and being up to and including 1 and n being from zero to less than 1, m being within the range of from 1.0 to 0.4 and n being in the range of from 0 to 0.6.  
 
     
     
         20 . The jet fuel composition as claimed in  claim 1 , wherein the comb polymer (vii) is a poly-1-alkene.  
     
     
         21 . The jet fuel composition as claimed in  claim 1 , wherein the comb polymer (vii) is a copolymer of at least one C 4 -C 6  1-alkene and at least one C 10 -C 14  1-alkene.  
     
     
         22 . The jet fuel composition as claimed in  claim 1 , wherein the comb polymer (vii) is a mixture of one or more comb polymers selected from the group of poly-1-alkenes and copolymers of at least one C 4 -C 6  1-alkene and at least one C 10 -C 14  1-alkene.  
     
     
         23 . The jet fuel composition as claimed in  claim 1 , wherein the comb polymer (vii) is C 8 -C 12  dialkylfumarate-vinyl acetate copolymer.  
     
     
         24 . The jet fuel composition as claimed in  claim 1 , wherein the polar nitrogen compound (viii) carries one or more amino substituents selected from the group consisting of mono- or di-dodecylamino, mono- or di-tetradecylamino, mono- or di-cocoamino and mono- or di-hydrogenated tallow amine.  
     
     
         25 . A process for reducing the pour point of jet fuels, the process including the following steps: 
 a) providing a jet fuel; and    b) adding at least one of the additives (i) to (viii) defined above in  claim 1  to the jet fuel.