1 reply to this topic

[Art Montemayor]

Helena:

Firstly, I believe this is an important subject; however, I also believe that it is placed in the wrong Forum. I think it rightfully belongs in the Relief Valve Forum. This won't cause any harm or commit any sins, but there are persons - like Phil Leckner - who frequent the Relief Valve Forum with timely visits and anyone who has any experience with Relief scenarios and their solutions knows about and respects Phil and his expertise on the subject. If you grant me permission I can move this thread to that locale. Just let me know if that is OK with you.

Next, I know that you can place several LP relief devices or Conservation vents on Storage tanks. I have used up to 4 on a single tank. However, these have always been placed on the tank's roof proper itself and never on a common manifold. The reason I had was that my tank was rated at maximum 15" of water column pressure and I could never justify a calculation that would be accurate enough to ensure that I wouldn't lose 15" W.C. of pressure drop through the manifold. Also, I didn't see any strategic advantage in the manifold since I had ready access from the tank's platform.

You don't say or state your relief type of scenario. For example, are you recovering the vapor? or are you interested in flaring 100% of the relief vapor? If not, then why not employ simple Emergency Reliefs?
Are you constrained or restricted by some process condition or scope of work that forces you to employ a manifold with all the relief devices on it? Or is this just an idea?

LP tank relief devices don't open 100% immediately when activated. They require extra pressure, since they are nothing more than weighed pallets working with gravity. If your tank set relief pressure is in excess of 1 or 2 psig, then you may have a case for applying a spring-loaded relief device and that might give you the ability to take a pressure drop on the inlet piping manifold. I think you can generate more direct and positive answers if you give us ALL your basic data: fluids involved, set pressures, size of tank(s), size of manifolds, length of inlet manifold, temperatures, relief scenario description and capacities involved, etc., etc.

I'll close for now and await your response. I believe you will recieve good, constructive comments and tips from our members if you give us the required basic data and scope of work.