1 reply to this topic

[parto]

Dear All,
I have 3 kinds of cone roof storage tank. each of tank has different Hidrostatic Head (H):
1. Dimension ; ID 9650 x 18177L ( Diameter: 9.65 m, Height : 18.177 m ) with
Hidrostatic Head ( H ) : 40 mmH2O
2. Dimension ; ID 14475 x 25476L ( Diameter: 14.475 m, Height : 25.476 m ) with
Hidrostatic Head ( H ) : 64 mmH2O
3. Dimension ; ID 7720 x 12698L ( Diameter: 7.720 m, Height : 12.698 ) with
Hidrostatic Head ( H ) : 110 mmH2O
all these tanks for palm oil storage. If I want to use Tank Blanketing Valve ( TBV ) and Breather Vent ( BV ). My BV has a minimum set point 21,971 mmH20.
Can I set my BV base on the Hidrostatic Head ( H ) ? Can we take the Hidrostatic Head from it's roof calculation and used it as the MAWP, so we can state the set point of BV based on this MAWP? Since the roof is the high risk part to be damage by over pressure and vacuum inside the tank.
Please help give me some advise for this case...

[proinwv]

I am not sure that I understand all that you are asking but first, you need to know the MAWP and MAWV of the tanks. You should not guess what this might be. You do not mention anything about vacuum but you need to protect against that due to mechanical failure of the TBV, loss of gas or any other situation. In my experience, more tanks fail from vacuum than pressure.

By hydrostatic head do you mean the pressure in the vapor space?

Your blanketing valve is to be set anywhere between the vacuum and pressure vent settings so that these three devices will not interfere with each other.

The vents must be sized so that under the worst case, they will maintain the tank pressure between the MAWV and MAWP.

There are papers on my website that go into this in detail.

Paul