Q & A > Question Details
One of the observations pertaining to 2 stage desalters is that 2nd stage efficiency remains poor as compare to 1st stage (50 to 60 % in 2nd stage as compare to 91 % in 1st stage) despite trying all necessary parameter adjustments such as Delta P, Fresh water flow, interface level, emulsion checking etc.
Is there a means of remedying this discrepancy?
 
Answers
10/08/2010 A: Christopher Turner, Snamprogetti Ltd, chris.turner@snampro.co.uk
It may be that you don't have enough water going into the second stage - talk to your desalter supplier for advice.
06/07/2009 A: Sam Lordo, Nalco Company, salordo@comcast.net
The question I would have is what is the actual salt number going to the 2nd stage? if it is low then the relative removal percentage may not be 90%, but something lower. If the salt going to the 2nd stage is >10 % then it would be reasonable to expect >90%. There are ways to calculate if it has reached the ideal level by determining the mixing efficiency (function of dehydration and salt removal) as well as determining the optimal salt content (function of the dehydration and inlet salt conc.)
06/07/2009 A: keith bowers, B and B Consulting, kebowers47@gmail.com
Check with your chemical supplier and get their specific recommendation for your particular combination of crudes, desalter configurations, and present chemical usage. Each situation is quite different and general comments are not much help sometimes. A better water:oil contact is required as is better settling of the water phase. Raising the temperature a few degrees may help.