Method and apparatus for improving the oxidative thermal stability of distillate fuel

Abstract

The present invention provides methods of improving the thermal oxidative stability of a distillate fuel which comprise selectively reducing the active concentration in the fuel of N—H containing heterocyclic aromatic compounds in which the nitrogen atom of the N—H group is part of the aromatic system, and wherein said fuel also contains an active concentration of metal compounds or will be exposed to active metal compounds in storage or in use. The present invention also provides methods of determining the thermal oxidative stability of a distillate fuel and apparatus for performing said methods.

1 - 46 . (canceled)  
     
     
         47 . A method for improving the thermal stability of a jet fuel which comprises selectively reducing the active concentration in the fuel of N—H containing heterocyclic aromatic compounds in which the nitrogen atom of the N—H group is part of the aromatic system, and wherein said fuel also contains an active concentration of metal compounds or will be exposed to active metal compounds in storage or in use.  
     
     
         48 . The method according to  claim 47 , wherein said fuel contains an active concentration of metal compounds, and which method further comprises reducing the active concentration of metal compounds present in the fuel.  
     
     
         49 . The method according to  claim 47 , which comprises selectively reducing the active concentration of deleterious N—H containing heterocyclic aromatic compounds by treatment with a suitable absorbent material.  
     
     
         50 . The method according to  claim 49 , wherein the suitable absorbent material comprises a compound having a benzaldehyde functionality supported on a suitable support.  
     
     
         51 . The method according to  claim 50 , wherein the compound having a benzaldehyde functionality is a 4-aminobenzaldehyde.  
     
     
         52 . The method according to  claim 51 , wherein the 4-aminobenzaldehyde is a 4-dialkylaminobenzaldehyde.  
     
     
         53 . The method according to  claim 52 , wherein the alkyl groups of the 4-dialkylaminobenzaldehyde are independently selected from methyl, ethyl, propyl and butyl.  
     
     
         54 . The method according to  claim 53 , wherein the 4-dialkylaminobenzaldehyde is 4-dimethylaminobenzaldehyde.  
     
     
         55 . The method according to  claim 50 , wherein the suitable support is selected from the group consisting of clays, carbons, aluminas, silicas and zeolites.  
     
     
         56 . The method according to  claim 50 , wherein the suitable support is a clay.  
     
     
         57 . The method according to  claim 56 , wherein the clay is a kaolinite.  
     
     
         58 . The method according to  claim 50 , wherein the compound having a benzaldehyde functionality is adsorbed on the suitable support to a level of at least 0.5 of a monolayer.  
     
     
         59 . The method according to  claim 50 , wherein the compound having a benzaldehyde functionality is adsorbed to a level of from 0.8 to 1.2 monolayers.  
     
     
         60 . The method according to  claim 57 , wherein the compound having a benzaldehyde functionality is 4-dimethylaminobenzaldehyde and the suitable support is kaolinite.  
     
     
         61 . The method according to  claim 47 , wherein the N—H containing heterocyclic aromatic compounds comprise one or more of pyrrole, indole, pyrazole, carbazole, substituted pyrroles, indoles, pyrazoles and carbazoles.  
     
     
         62 . The method according to  claim 47 , wherein the N—H containing heterocyclic aromatic compounds comprise one or more of pyrrole, indole, substituted pyrroles and substituted indoles.  
     
     
         63 . The method according to  claim 48 , wherein the N—H containing heterocyclic aromatic compounds comprise one or more of pyrrole, indole, substituted pyrroles and substituted indoles.  
     
     
         64 . The method according to  claim 49 , wherein the N—H containing heterocyclic aromatic compounds comprise one or more of pyrrole, indole, substituted pyrroles and substituted indoles.  
     
     
         65 . The method according to  claim 50 , wherein the N—H containing heterocyclic aromatic compounds comprise one or more of pyrrole, indole, substituted pyrroles and substituted indoles.  
     
     
         66 . The method according to  claim 51 , wherein the N—H containing heterocyclic aromatic compounds comprise one or more of pyrrole, indole, substituted pyrroles and substituted indoles.  
     
     
         67 . The method according to  claim 52 , wherein the N—H containing heterocyclic aromatic compounds comprise one or more of pyrrole, indole, substituted pyrroles and substituted indoles.  
     
     
         68 . The method according to  claim 53 , wherein the N—H containing heterocyclic aromatic compounds comprise one or more of pyrrole, indole, substituted pyrroles and substituted indoles.  
     
     
         69 . The method according to  claim 55 , wherein the N—H containing heterocyclic aromatic compounds comprise one or more of pyrrole, indole, substituted pyrroles and substituted indoles.  
     
     
         70 . The method according to  claim 60 , wherein the N—H containing heterocyclic aromatic compounds comprise one or more of pyrrole, indole, substituted pyrroles and substituted indoles.  
     
     
         71 . The method according to  claim 47 , wherein the metal compounds comprise compounds of transition metals.  
     
     
         72 . The method according to  claim 47 , wherein the metal compounds comprise copper and/or iron compounds present in the fuel.  
     
     
         73 . The method according to  claim 48 , wherein the metal compounds comprise copper and/or iron compounds present in the fuel.  
     
     
         74 . The method according to  claim 49 , wherein the metal compounds comprise copper and/or iron compounds present in the fuel.  
     
     
         75 . The method according to  claim 50 , wherein the metal compounds comprise copper and/or iron compounds present in the fuel.  
     
     
         76 . The method according to  claim 70 , wherein the metal compounds comprise copper and/or iron compounds present in the fuel.