Hi every one:
Can any one help me in Pressure relieve valve calculation. I am trying to calculate PSV for Capacity Case. I don't know how to find the Relieve Flow rate (W). Is there any one who can tell me the equation through which i can find the Relieve flow rate(W).
The equation I am using is (A=((W*sqrt(T*Z))/(CKP1Kb*sqrt(M))
I need to find the value of W in this equation.
I appreciate for your help in advance.

This is a well discussed topic. Did you search the old posts?

There is detail explanation in API RP 520 ed7, section 3.6.2.1.1.

The nature of the question suggests that you are fresh at PSV calculations. Firstly, you need to define the applicable emergency scenarios. Apart from API 520 it would be useful if your company had a calculation manual or procedure for PSV design.

In any case, the best answer i can come up with is:

• Check the P&ID, visualize the upset conditions possible.
• Calculate the mass and heat in
• Calculate the mass and heat out
• Relieve the difference
• Do this for all possible cases and chose the governing case.

I do not have extensive in PSV design, so I normally give a lot of importance to PSV calculations as personel and equipment are at stake here. I try to read up as much i can and wherever possible discuss with other engineers.

Thanks.
Ashetty