ammonia separator level

[l2embo]

Dear friends
is there any standard pointing out the suggested liquid level of ammonia in separators? we have -10 and -40 ammonia separator whit pumps installed under the vessels. I am asking this question for installing the feeding and high level switch or transmitters. is 30% of height convenient for feeding switch and 60% of height for high level?

[MrFreez717]

There is no "standard" for this. In general, you need enough liquid in the separator to supply adequate suction head for your pumps. Excess liquid beyond this point is not really doing you any favors, especially if the defrost condensate is going to wind up in this same vessel. If you have performance curves for your pumps, and you know what flow they need to deliver, you can see how many meters of positive suction head are required. This distance is from the centerline of the pump inlet to the liquid level in your vessel. I suggest adding about half a meter of "cushion" above that level, and using that point as your liquid level target.

For the high level, you are limited by how much cross-sectional vapor space area you need to ensure proper separation of liquid and vapor when the system is fully loaded. This should be determined by the system designer, and is typically around the centerline of a horizontal vessel.

Best regards,
MrFreez717

[NH3LVR]

Excellent answer MrFreez717.

l2embo:
You have a lot of things to consider.
I am not sure what resources you have available to you there.
A design engineer take a lot into mind.
Net Positive Suction Head is extremely important.
Here is a link to that. https://www.michael-smith-engineers....%20cavitation.

And a sample pump curve showing the NPSH needed.
https://ecatalog.cornellpump.com/#/pump/2CB

As to the separation space required that is based on the velocity of the gas to ensure liquid fallout.
Vessel design can have an effect as well. For instance if you have two suctions leaving the vessel from opposite sides, you can increase the effective size of the vessel.
As you can see your questions can only be answered if you have the information for your particular vessel and pump.