How can I estimate a resident time. Is there any equation or chart for that?. After I have recieved a oil produccion (16 API)then it is storge in a tank, What will be the resident time for drain the water and be treated later.
This is a difficult one to calculate. It depends on temperature of the crude oil going into the tank, the ambient temperature, flow rate or amount of tuburlence in the tank, etc. I had conducted experiments, where tanks were designed for 24 hours retention time, had the inlet short circuited to the outlet in 6 seconds. Are you also adding any emulsifier or de-emulsifier into the crude oil ?
To start with a simple sampling of your crude oil and letting it stand will provide you a guide line to figure out the required retention time.
Alot also depends on the design of the water collection facility, eg: say, a spider web design. etc.
In the experiment conducted, tritium (radioactive water) was injected into the inlet of the pipe and a gieger counter was located on the discharge piping. And by gum, I was sure surprised with the 6 seconds result that I got!
When the inlet is at or near the tank bottom, and the outlet is at of near the tank bottom, the residence time is how long the material takes to travel from the inlet to the outlet.
To have any residence time then the outlet or inlet must be at a different level, which would be an unusual design