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Tank Overflow Pipeline Layout

Tank Overflow Pipeline Layout

(OP)
Produced water overflow pipeline from many Tanks is routed to an Overflow Header which finally ends up in an Open Pit (for use during emergencies)in a existing Produced Water Handling Unit. Overflow pipeline from Tanks joins the header from below ground as shown in the attached simple sketch. Wish to know if this type of gravity flow piping configuration is the best design practise or it would have been better if it joins the Overflow Header from the top of pipe.

RE: Tank Overflow Pipeline Layout

Looking at your picture, it would appear that liquids going to the Overflow Header would flow into the overflow pipes for the tanks prior to anything getting to the Open Pit.

RE: Tank Overflow Pipeline Layout

The problem with that type of arrangement is that you will trap air in the pipes and the trapped air will lessen the flow rate.

RE: Tank Overflow Pipeline Layout

(OP)
yes please produced water from tank first enters overflow pipes 24"/36" which then joins the 36" header. 36" header is above ground near the Tanks and goes below ground outside the Unit and all the way to Open Pits

RE: Tank Overflow Pipeline Layout

(OP)
Kindly share guidelines for tank overflow piping layout design

RE: Tank Overflow Pipeline Layout

verbabu,

Your sketch is very low on details, but from what I understand you have some lines which come off different tanks the run below ground?? before coming vertically up into a header before this header flows with gravity, so has a fall of ?1:100? to some mysterious pit.

Normally you don't flow into the bottom of a gravity header because apart from the potential to get air blockage, any dirt or items heavier than water will sink down into your connecting pipes.

However, it all depends on details such as heights, falls, distances, any dirt in the water?, things like that.

In general for pipes like this avoid sumps and syphons and try to get gradual falls in a continuous fashion and allow for some vents on the main header pipe

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

RE: Tank Overflow Pipeline Layout

(OP)
thanks to all for your feedback which had the right & appropriate ideas for the issue I had.

RE: Tank Overflow Pipeline Layout

verbabu, your thread is useless now, you have had no answers, why don't you answer the questions Little asked?

RE: Tank Overflow Pipeline Layout

If there is an U leg in each tank's overflow line before it joins the main header, and the U leg is meant to be liquid sealed, this arrangement may have been set up to prevent migration of gas ( with HSE concern) from one tank to the other tanks connected to the same collection header.

RE: Tank Overflow Pipeline Layout

What is the purpose of the tank? Are there valves located at each underground branch riser and in the horizontal pipe between them. Which valves are closed if any? Is there a separate vent pipe from the tank that is open above ground at highest elevation?
Note that if the tank is full, it will remain full and all the discharge water will go to the open pit.
Is there a pump that will allow the tank to be emptied? Where does the pump discharge?
Is there provision to allow chemicals to be put in the tank to possibly treat its contents prior to discharge?

RE: Tank Overflow Pipeline Layout

George makes a very good point. If the overflow is connected without any air gap or vent, then in essence you are connecting all the vapour gaps in each tank to another, which is not usually a good thing. Blowback of a gas in a flare header or similar vent can be very dangerous if explosive or noxious gases are involved.

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

RE: Tank Overflow Pipeline Layout

(OP)
Pardon me for the delay in reverting back to your queries. the 36" portion above ground near the tanks is now being shifted to below ground due to issue related to access area around tanks for cranes during maintenance. attached is a sketch showing the tank overflow lines connection to the overflow header after the modification of 36" from above ground to below ground.

RE: Tank Overflow Pipeline Layout

I really don't understand how this system works.

Tank 1 seems to have no vent and will fluctuate pressure based on the static head of the U bend. Not sure what the PG is on top of the tank - Pressure guage?

Tank 2, pressure in the tank is maintained at the hydrostatic level in the water trap U bend, but tying the vent line into the overflow line looks very odd

Tank 3 though seems to then operate at below atmospheric, though how the vacuum is applied is not clear as it looks like air would simply enter from the open end of the pipe going to the open pit?? All your FG blanketing just disappears down the vent line.

I think you need to draw this up properly and be a lot more open with whatever this tank farm is.

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

RE: Tank Overflow Pipeline Layout

How would the FG blanket on T3 work if there is no U leg on the overflow lines from this tank?

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