4 replies to this topic

[obsidian_dust]

Within a month, we found two batches of jet fuel has a slightly pink color (pinkish). This is our first experience so nobody has an exact answer about the cause. In our refinery, jet fuel is a blend of two streams from two different unit : a Kerosene Merox Unit and a kerosene hydrotreater. The normal color is pale yellow. Once I read in the Def Stan that the unusual color (including pink) could be caused by crude oil characteristic. Unfortunately, no further information about which crude characteristic could lead to this condition.

If somebody has ever have similar experience or helpful information to share, it will be greatly appreciated.

[Zauberberg]

For the beginning, try to identify the source of color change, i.e. whether it comes from the hydrotreated or Caustic-treated jet fuel. It shouldn't be a storage issue in any case.

We used to have similar problems with jet fuel Water Reaction test, something like a slime used to form during Lab analysis. It is related to the potential of jet fuel to retain water, and in many cases this corresponds to high Naphthenic Acid content (or Crude origin/contamination). You may try to reduce the cut point of Kerosene from CDU and see if there will be any improvements.

Has any other property of Jet Fuel been changed, along with the color?

[obsidian_dust]

Zauberberg,

Thanks a lot for the helpful advice. Other than slightly pink color, all of the quality parameter - including the particulate - is good. The Saybolt color test of the streams went to that batch is good as well. You said about the effect from naphtenic content, shouldn't it be represented by Total Acid Number which is one of the quality parameters specified for jet fuel?
Do you have any experience about the likeliness of color deterioration of kerosene sweetened in Merox Unit?

[Zauberberg]

Nothing apart from Caustic carryover, which is easily confirmed by checking residual water content and determining pH. Saybolt color should be 30 if I remember well, and Water Reaction test is not considered as crucial for jet fuel quality.

There is a special test method for determining Naphthenic Acid content in petroleum cuts but I cannot remember which of the ASTM methods it is. Reducing kerosene cut point is a nice field experimentation since lighter product results in lower NAN as well, and this might improve the product quality. In any case, as long as the commercial quality of Kerosene is not affected with this change, there's nothing special to worry about.

There's a very handy document about jet fuels published by Chevron some time ago. You can read it at: http://www.chevrongl...ookmarks&page=1

[obsidian_dust]

Zauberberg,

Thank you very much for the helpful information. And thanks for the good reference as well. Best regards.