5 replies to this topic

[rahul22yadav]

Dear Process Engineers,

I want to know why do we require to mention crtitical pressure in Control valve datasheets.

[breizh]

Rahul,
Consider this resource to support your query .

Breizh

[rahul22yadav]

Thanks for ur reply,

So actually this is applicable where there are chances of chocked flow though control valve.

[sini_4s]

hello,

I am new to the forum.
I have question regarding the critical pressure?
What if the customer doesn't specify the critical pressure for the application like Solvent + HCs?

[PaoloPemi]

possibly the resource suggested by breizh suggest a solution,
the formulation to evaluate allowable pressure drop with liquids (chocked flow due to flashing or cavitation) is for pure fluids,
for mixtures things are more difficult, consider for example wide boiling mixtures,
for these cases I average values,
the properties of many fluids are available in books (for example Perry's chemical engineering handbook, Prausnitz's Properties of gases and liquids etc.) or Excel's files etc.

[sini_4s]

Thanks paolo for the reply