PSV vs Liquid Seal
PSV vs Liquid Seal
(OP)
Hello All,
I have a liquid seal that is used as overpressure protection on a vent system off of a reactor set at 16.5 psig. I am wondering, in general, what promts the use of a liquid seal vs a PSV or rupture disk for this application? We have a pressure control valve on the vent piping so it does not appear that it is there to maintain the header pressure.
Are there situations where one would be advantageous over another?
Thank you very much.
David
I have a liquid seal that is used as overpressure protection on a vent system off of a reactor set at 16.5 psig. I am wondering, in general, what promts the use of a liquid seal vs a PSV or rupture disk for this application? We have a pressure control valve on the vent piping so it does not appear that it is there to maintain the header pressure.
Are there situations where one would be advantageous over another?
Thank you very much.
David





RE: PSV vs Liquid Seal
2.) If on a vessel, is the 16.5-psig the actual MAWP or is it relieving pressure -- looks like 15-psig +10% ???
RE: PSV vs Liquid Seal
16.5 psig is the relieving pressure. We are unsure what the actual MAWP is on the vessel as it is 40 years old, fabricated in Germany, and little documentation exists.
Please let me know if I can provide any more information.
RE: PSV vs Liquid Seal
The wet vent would corrode normal materials used for vent pressure relief.
Admittedly, the liquid seal did not "scrub" a high percentage of gases.
More recently, vendors offer FRP devices for corrosive gases.
I once saw a single liquid seal connected to the vent of eight tanks. The service was wet aldehydes(smelly).
The focus was odor control and "being cheap" by not having individual PV devices on eight tanks.
The "activation" accuracy of a liquid seal could be cited as an advantage when compared to either a 15-psig PSV or 15-psig rupture disk.
I recommend hiring a professional to rate your vessel to determine MAWP.
RE: PSV vs Liquid Seal
RE: PSV vs Liquid Seal
Are you suggesting that the seal leg does not qualify as a relief device?
I was wondering when one would choose between a seal leg and a PSV.
Regards,
RE: PSV vs Liquid Seal
RE: PSV vs Liquid Seal