Hi all,
I am rating a rupture disk for a flashed two-phase flow with 0.1% vapor manly consisting of methane and some CO2. Per API 520-1 Annex C, if I have 'some' non-condensable gas, I can use Direct Integration Method or Omega Method for calculation of two-phase relief area.
I used both Liquid-only flow (API 520-1 eqn 33) method and two-phase flow method (API 520 Part 1 eqn C.10), and as per the results, the calculated liquid-only area is 10% higher (i.e. more conservative) than two-phase calculated area.
My question is,
- Is it Direct Integration Method or Omega Method is a correct choice for this application (i.e. 99.9% liquid or 0.1% vapor)?
- What does API mean by 'some noncondensable gas, is it 0.1%, 1%, 5% or 10%? Do they have any guideline?
Regards,
Sanjay