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This question is related to kerosene merox unit. After processing kerosene in merox unit, what are the main reasons for poor saybolt color of kerosene product? If kerosene feed to the merox unit has saybolt color of +26, kerosene product from merox unit observes saybolt color of <16. Can someone explain the possible compounds which causes color problems to the kerosene product? If we go to Kerosene Hydrotreater, there will not be any issues of color problems and in fact it will be improved because of olefin and aromatic saturation. Please share any literature or chemistry related to the kerosene color problems in merox units.
14/04/2015 A: manshoor bukhari, Mid country refinery PARCO, manshoorbukhari@gmail.com
Colour deterioration of kerosene product from Merox unit is a rare phenomena that occurs when naphtenic acids carry over from electrostatic coalescer to reactor due to poor efficency of electrostatic coalescer. Color also diminishes due to excess air causing over oxidation in merox reactor. Usually merox operators do not allow these factors to distort the product. Feed contaminates are the foremost cause of color problem of kerosene product. In our experience processing thermally cracked slop mixed in crude often found responsible for the said color problem.
07/01/2015 A: Krishna Rao Pulugurti, Retired/Consultant, pkrao2012@yahoo.com
The color of ATF Merox Run Down may come deteriorate due to any of the following:
1. Mercaptan content in Feed ATF is high: Mercaptans are converted to disulfides which are brown in color and impart yellow color to ATF
2. Basic nitrogen is high: Basic nitrogen when comes in contact with oxygen imparts yellow color to ATF/Kerosene. ATF obtained from some crudes has high basic nitrogen.
3. Organic acidity is high: High Organic acidity along with high basic nitrogen is believed to impart yellow color.
4. Disulfide contamination from oxidizer caustic:Disulfides can enter the Merox through spent caustic. They impart yellow color. You can check this by testing ATF before and after Merox. If the total sulfur is higher in Merox R/D than the feed, it indicated disulfide ingress.
06/01/2015 A: Sridhar Balakrishnan, Bharat Oman Refineries Limited , laksrid@yahoo.com
For the kerosene colour to deteriorate the main reason be colour precursors already existing in Kerosene. Mostly they are oxygenated and nitrogenous compounds. Some of the aryl sulphur compounds can also cause the colour decrease in kerosene. Crude Oil type matters a lot for kerosene colour deterioration.