Q & A > Question Details
We are facing color problem in our Crude Distillation Column, during processing Color of Naphtha noted +17 instead of +30 what are the possible causes of this color problem.
Also color of Kerosene become off spec +10 instead of +30 or +28 what are the possible causes of this problem.
We checked all the heat exchangers for Possible leakage but no leakage observed.
 
Answers
16/09/2016 A: Muhammad Faisal, OQ integrated energy company (Oman), engr.faisalfraz@gmail.com
For Naphtha colour issue, check EP or you may reduce and observe any colour change. as mentioned earlier, reformate SLOP (Green oil formation in reformate absorbents etc) can impact the SRN Colour.
For Kerosene colour issue: two things: (1):any slop processing that contribute within the BP range of Kerosene. OR check EP of kerosene. reduce the EP and test the colour for any improvement. if there is no exchanger leak confirmed. (2): for colour improvement in Kerosene Merox treatment, foucs should be given to optimize all parameters i.e. colour for Kero feed to merox, after electrostatic prewash, after water wash, after clay filter colour. how's caustic saturation in R's caustic settler, whether all the oxygenates/naphthanic acid has been removed in prewash. these are all also source of discolouration.
15/09/2016 A: Sudhakara Babu Marpudi, Dangote Oil Refinery Company, m_sudhakarababu@yahoo.com
Presence of cracked slops in the feed blend and higher Phenol levels in feeds are the possible reasons for coloured products. High Nitrogen levels in Crude mix is an indication too. Some Crudes like Kole Marine, Ras Gharib were observed to have very dark coloured Jet fuel. Normally phenols should land up in Kero / jet fuel stream. So lowering the furnace outlet temperature must help in preventing Color compound entry to Naphtha stream.
02/09/2016 A: RAUL FLORES, PDVSA INTEVEP, fraulf@hotmail.com
- Slops: to produce jet fuel via kerosene do not process slops even at very small ammount as 0.1 - 0.5 %; it is a high risk because could deviate MSEP, JFTOT, and Color parameters
- Feed/crudes: some of them could have precursors/compounds/contaminants that could colorize the white products; a "pink" color is attributed to phenol compounds, for example
- Changes/deviation on operation: pay attention to suddenly use of "anti..." compounds; be aware with the final boiling point of cuts; leaks by pumps or by any equipment before the inlet of the feed and/or before the point of sampling the product to be analized or stored; inspection and closing equipments protocols not strictly followed (foreing matter/objects left in site)
The quality of white products, jet fuel the first, is highly dependent on the history of the operation conditions and/or the feed.
01/09/2016 A: Sridhar Balakrishnan, Bharat Oman Refineries Limited , laksrid@yahoo.com
The colour of distillates deteriorates due to active hydrocarbon colour precursors which are present in crude oil itself . Some of the crude oil kerosene cut saybolt colour goes down due to some active colour species like nitrogenous and oxygenated compounds are present Another reason is processing high acid crudes in crude slate can also affect the colour of distillates. .
01/09/2016 A: RAUL FLORES, PDVSA INTEVEP, fraulf@hotmail.com
Please inform present crude feed or changes on it, and crude type/name when no colour deviation was observed on white products.
31/08/2016 A: Peter Marsh, XBP Refining Consultants Ltd, peter.marsh@xbprefining.co.uk
Check that no cracked product slops have inadvertently been routed to the Crude Distillation Unit (CDU). Alternatively, if the naphtha feed to the naphtha hydrotreater (NHT) has a green tinge, it may contain a significant fraction of reprocessed reformate slops.
31/08/2016 A: Bruce Carr, Suncor Inc, matukaze1@hotmail.com
Have you checked the end points? That will tell you what is contaminating the streams.