close drain position under or above ground 1

[maatoug]

hi every one , hope you are doing well,

about a close drain vessel position under ground or above ground which the best solution? please advice

 

[1503-44]

Above ground is preferred. Access is less complicated.

“What I told you was true ... from a certain point of view.” - Obi-Wan Kenobi, "Return of the Jedi"

 

[maatoug]

agreed about access but what about process issues as example pumps if we can rich a fully drainage

 

[LittleInch]

Depends on where your drain points are.

A closed drain system normally relies on gravity flow, hence the tank needs to be lower than the lowest drain point, otherwise it won't drain.

For many systems this means the closed drain tank needs to be buried.

Either double skin or in a deep pit which fills with water, snakes, leaves and is a complete pain.

But you can't beat gravity. It only works one way.

So unless you can attach a portable pump to the drain and then pump it up or pressurises the pipe using Nitrogen or similar to blow the liquid up into the drain tank, the top of the tank needs to be lower than the drain, hence why most are buried. IMHO.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[1503-44]

I thought you were wondering where the drain valve goes.
Everybody knows a drain vessel can go anywhere that will catch the drainage, which for gravity drainage is always lower than the thing being drained, irregardless of there being dirt to bury it in or not. There are lots of drain vessels located in basements and lower levels of offshore platforms, far away from dirt. Did you really ask that?

“What I told you was true ... from a certain point of view.” - Obi-Wan Kenobi, "Return of the Jedi"

 

[georgeverghese]

In many onshore locations, the closed drain vessel is in a below ground level open pit. The CD transfer pump in this pit can be below this vessel, or it can be a vertical turbine pump mounted on vessel top. Since this pit will not be well ventilated, electrical pumps and all instrumentation may most likely be for IP Zone 1 service - check with your plant process engineer / electrical engineer.

You could ask for a rain shelter above this pit to minimise the use of the pit open drains pump.

Beware of sneaky attempts by design engineers to use this maintenance service CD drum in continuous process drains service - you almost always end up shooting yourself in the foot, from an Operations point of view.