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Heavy crude oil desalting in electrostatic desalter designed for normal crude creates interface level problem and results in more oil in desalter effluent. What best operating and design practices should be followed to overcome this problem?
 
Answers
22/04/2014 A: Ankur Verma, Bharat Petroleum Corporation Limited, ankur.biet@gmail.com
Oil in desalter effluent is coming because of oil-in-water emulsion formation. Injection of high molecular weight cationic surfactants with demulsifiers may solve your problem. Selection of these surfactants needs laboratory testing since the selection highly depends on crude blend.
01/09/2009 A: Morgan Rodwell, Fluor Canada Limited, morgan.rodwell@fluor.com
I would concur with Eric Vetters on his advice. One other concern is that heavy crudes often have significantly higher viscosities than traditional crudes, even at the elevated temperature of a desalter. This can result in lessened mobility of water droplets, which makes coalescence more difficult. The consequence is that the maximum throughput one can achieve on heavy crudes (e.g. oil sands diluted bitumen) is lower than for conventional crudes for a given desalter vessel size.
09/02/2009 A: Eric Vetters, CorrMat International LLC, ewvetters@yahoo.com
Controlling pH of the desalter wash water and optimizing mix valve delta P are important. Naphthenic acids in heavy crudes can cause emulsion formation when high pH water is used. Excessive mix valve DP can exacerbate rag layer formation. Re-evaluation of emulsion breaking chemistries employed is also important. High solids levels in heavy crudes can promote rag layer formation and oil under carry in the desalter. In addition to primary emulsion breakers, you may need to look at things like wetting agents or asphaltene dispersants/stabilizers to better manage the desalters. Optimizing your mudwashing process is also important. Too much mudwashing keeps the desalter routinely upset. Too little allows solids to collect in the desalter, which will eventually force a shut down.
07/02/2009 A: keith bowers, B and B Consulting, kebowers47@gmail.com
How heavy? Increasing the temperature always helps tow ways--by decreasing crude viscosity AND by decreasing the density of the crude relative to the water.
08/05/2008 A: Omer Elhaj, Khartoum Refinery Co.Ltd, hajaliomer@yahoo.co.uk
First you have to improve the dewatering process in the oil field then in the refinery tanks farm, then by using the suitable quantity of chemical demulsifier and optimizing the operation conditions of the desalter itself you will succeed .
16/04/2008 A: Saugata Palit, Intercat India Ltd, spalit@intercatinc.com
Mixing calculated amount of demulsifier chemical along with crude, before the crude enters the desalter vessel may solve the problem to some extent.
07/04/2008 A: Pablo Contreras, Alberta Research Council, pablo.contreras@arc.ab.ca
Interface level problems and oil in desalter effluent can be reduced with the injection of some specific chemistries. Lab tests are necessaries to define products and estimate dosages.
08/02/2008 A: Simone Robinson, Tube Tech International Ltd, simone@tubetech.com
Could you provide me with an outline of your cleaning and maintenance practises - from this information we might be able to suggest some options.