Tank Vents - Plastic Bags - Pressure events ? (even possible)

[mrtangent2]

This is a curious question Ive been asked. Im quite familiar with a plastic bag blocking a API tank vent and a vacuum being pulled with resulting tank damage => and see it first hand many years ago as a student on an API MEOH Tank.

But, Im fairly sure the answer is NO.. but for API tanks is the probability and do events happen with a budged tank from a vent blockage and over pressure .. e.g with the "right" bit of "crap" so to speak.. is this a credible tank over pressure case .. say from inerts still purging blocked vents..

i think the pressure build would be so slow that its just not likely and doesnt happen..

but i'd like to hear others thougth's on this

 

[LittleInch]

I would say its absolutely possible. The question is then how possible?

If you have material which can turn solid then the probability increases.

If you have bird or insect mesh the probability increases.

If you have any sort of pressure valve and not a free vent the probability increases.

Nesting birds?

Plastic bags might be less so.

Pressure build can be quite fast depending on liquid inflow rate.

Oh and please define API tank. There are more than one standard.

 

[pierreick]

My experience, this happened:
- vent blocked on phenol tank (crystallization), tank partially collapsed. This was wintertime and cold N2 to blanket the sky of the tank.

Pierre

 

[HTURKAK]

One of the vacuum collapse case ,
Notice the plastic bag on the vent valve . The painters forgot to remove after painting.

Vacuum collapse of vented tanks may occur due to several reasons, such as;
- Blocked vent pipe: If a vent pipe is blocked, such as by a plastic cover left in place during painting, it prevents air from entering the tank, creating a vacuum when liquid is withdrawn.
-Rapid cooling: The cooling of tank contents may decrease the vapor pressure, leading to a vacuum inside the tank.
- Steam cleaning: When water vapor is introduced into a tank and then cooled, it condenses into liquid water, reducing the internal pressure and causing a vacuum.
- Loss of electrical power can shut down valves and controllers, affecting the venting system and potentially causing a vacuum.