I'm a new process engineer in the industry, still in my first year out of college. I'm working on the design of central processing facilities for crude oil.
I'm designing a central processing facility to process light crude (about 50 API). Currently my vessel train consists of a High Pressure 3 Phase separator at the inlet followed by a Lower Pressure Heater Treater, Air Cooler, and atmospheric pressure Vapor Recovery Tower before storing the oil in the tank battery. I have been tasked with investigating the use of a "Gun Barrel" tank at the end of my process train before the Oil is finally stored in atmospheric tanks. Gun Barrel tank also known as a settling tank or a wash tank.
Gun barrel settling tank - OilfieldWiki
I'm hung up on a few things with the Gun Barrel Tank.
1. It is essentially just another separation vessel one inlet three outlets not a "Storage Tank" per se
2. The hydraulics of the whole system rely on natural flow from the well to the tanks. The Vapor Recover Tower operates at atmospheric pressure relying on the height of the 40' Tower of Oil to get the Oil to the Tall storage 30' Tanks. I'm concerned inserting another vessel between those two could create too much head loss for natural flow in the storage tanks.
3. The addition of the Gun Barrel Tanks adds two additional process lines to deal with as it has vapor water and crude outlets. The vapor and crude outlets are no big deal, but the water outlet will most likely have to be pumped to the 30' storage tanks.
4. I'm expecting the Crude entering the Gun Barrel tank to be <1-2% water by volume. What kind of purity would I see from water exiting the bottom of the vessel with such low concentrations of water entering?
If anyone has any experience using these Gun Barrel tanks any input, knowledge, or advice would be appreciated, especially in series with a Vapor Recovery Tower. To be more specific, what would a typical inlet concentration of Water in Oil be, what kind of purity would one expect on the water and oil outlets.
Edited by kengor10, 10 December 2021 - 09:04 AM.