Relief capacity partially underground tank
Relief capacity partially underground tank
(OP)
I have a tankfarm with several tanks partially underground. Only the top klopper head with the manhole an nozzles is above ground. Is fire case a credible scenario and how to calculate the relief rate?
In my opinion fire case is a credible scenario an I thought to calculate the effective discharge area according to "4.4.13.2.4.3 Heat Absorption Equations for Vessels Containing Only Gases, Vapors, or Supercritical Fluids" with equation 8, 9 and 10 from API RP521:2014. This applies to unwetted area, but for vessels containing only gas.
All the wetted parts of the vessel are underground, only the head of the vessel is above ground. The design pressure of the vessel is 500 mbarg.
Is this the correct method to calculated the required discharge area/relief capacity of the pressure relief valve?
In my opinion fire case is a credible scenario an I thought to calculate the effective discharge area according to "4.4.13.2.4.3 Heat Absorption Equations for Vessels Containing Only Gases, Vapors, or Supercritical Fluids" with equation 8, 9 and 10 from API RP521:2014. This applies to unwetted area, but for vessels containing only gas.
All the wetted parts of the vessel are underground, only the head of the vessel is above ground. The design pressure of the vessel is 500 mbarg.
Is this the correct method to calculated the required discharge area/relief capacity of the pressure relief valve?





RE: Relief capacity partially underground tank
Good luck,
Latexman
Technically, the glass is always full - 1/2 air and 1/2 water.
RE: Relief capacity partially underground tank
I would not expect much relief either, but can I use the equations used for thermal expansion for gas filled tanks?
The tanks contain aceton, ethanol, methanol or other liqht solvents.
RE: Relief capacity partially underground tank
RE: Relief capacity partially underground tank
In the case you describe, there is no liquid in contact with the vessel wall which is exposed to fire. Regardless of how you size this PSV, it won't provide any meaningful protection from fire. Provide a PSV (any size) for regulatory compliance, and then consider other protective measures which will at least partially protect from fire (water spray, de-pressurization, insulation).