Q & A > Question Details
Refinery Practice is to add Demusifier at the upstream of Desalter. But some Refineries also inject Demusifier at the Suction of Crude Charge Pump. Which is better?
 
Answers
22/03/2014 A: Eric Vetters, ProCorr Consulting Services, ewvetters@yahoo.com
Generally the further upstream you add the demulsifier the better. It gives the chemistry more time to thoroughly mix with the oil and to interact with things like solids for improved wettability. Some chemical suppliers advocate injecting a part of the chemical upstream of tankage even, but that creates a number of other possible issues. One supplier claims that by putting part of the demulsifier in with the oil and part in with the wash water that total demulsifier usage can be decreased.
One key aspect of where to carry out the injection is to make sure that the right people have the ownership and control of the injection. If your crude charge pump is located in the tank farm, sometimes its operation will be under the control of tank farm operators. In that situation if there is a desalter upset, then having to get tank farm operators to increase the demulsifier dosage could slow down response to the upset.
When deciding on where the injection point should be, you need to consider not only what is the most effective location, but also how it can be best managed and operated.