Tank Vent Sizing/Rating

[sanchem]

We have an empty tank of 4 m3 volume. Height = Dia = 1.6 m.
Tank has a vent of size 1 inch. Tank doesn't have any PSV.

Now, we are going to use this tank for storing a chemical X.
In case of external fire scenario, I want to check if this 1 inch vent size is suitable for venting the vapors.

Tank Design pressure = 6 kg/cm2g
Vapor Pressure of chemical X = 6 kg/cm2 @385 Deg C

Kindly advice what should be the criteria for vent sizing?

 

[Latexman]

API 2000, 520 Part I, 520 Part II, and 521 have the criteria.

Good luck,
Latexman

To a ChE, the glass is always full - 1/2 air and 1/2 water.

 

[bimr]

1-Inch vent size is certainly too small. Follow the advice of Latexman above.

 

[don1980]

Since this is a pressure vessel rather than a low-pressure tank, the applicable heat input calculations are those in API 521. Fire resistant insulation may get the heat load down low enough for the existing 1" nozzle - you'll just have to do the calculations to see how thick that insulation would need to be in order to get the heat load (relief load) low enough for the 1" nozzle.