Tank inlet distributer

[Murec]

I have to design an inlet distributer pipe for a produced oil tank.
Ususally these are horizontal pipes with a number of slots or holes for distributing the flow across the lower part of the tank.
In this case we want to promote the release of gases from the incoming liquid. Gases should be released in the tank headspace and removed by a Vapour Recovery Unit (VRU) so there is no environmental issue.
The proposed layout is a vertical pipe with slots in it. Liquid should flow upward and then overflow through the slots above the liquid level in the tank, gas should keep travelling upward. The first idea is to calculate the slots as flow over a weir, however there must be some flow, maybe significant, through the submerged slots.
Has anyone encountered such pipes? Could anyone suggest ways to calculate flow velocities and slots size?
Thank you in advance.
M

 

[BigInch]

If you flow out slots which are located above the oil level in the tank, you're going to do nothing except mix more air into the oil.

http://virtualpipeline.spaces.msn.com

 

[Murec]

No, the slots would cover the length of the pipe, starting at an elevation below the minimum level and going up to close to the max level.

 

[JStephen]

You should be able to calculate flow through the slots like flow through an orifice. Apply Bernoulis' equation between, say, the centerline of the pipe and the center of the orifice. Assume negligible velocity at the pipe centerline, and solve for velocity at the slot as a function of the pressure differential.

 

[BigInch]

I would think you would want a large full flow cross sectional area of the slots with only a very minimal pressure drop, if any at all. Any significant exit velocity through the slots would carry your bubbles with the oil flow into the tank.

http://virtualpipeline.spaces.msn.com