Steam pressure reduction calculation

[ghensky]

Steam at 30 PSIG is axially entering into an atmospheric gas-liquid separator. Because of the axial entrance, steam is in cyclonic motion inside the separator. While some of it condenses into water and leaves the separator from the bottom outlet, most of it leaves the separator from the top outlet.

I'm trying to find a way to calculate the steam's eject pressure and velocity off the separator but with no luck. I know that much that the exit pressure has to be higher than the atmospheric pressure but lower than the inlet pressure. Any input would be appreciated. Thanks.

 

[lilliput1]

You have to know the mass of steam entering then calculate the amount of flash steam. Using the specific volume of steam solve for the exit velocity though the steam outlet. This would just be an approximation.

 

[ghensky]

Thanks lilliput1.
1. It is already steam that is entering, so why calculating for the flash steam?
2. Because there is a pressure reduction (from 30 PSIG to atmospheric), the additional energy is expended for the volume expansion. That's the only explanation I can think of to answer "what happens to steam at reduced pressure".
3. Is it possible to measure the pressure loss due to the swirling motio?

 

[lilliput1]

Sorry I was thinking of high pressure condensate but why are you wasting steam? Is this leakage from a safety valve? If so, replace the safety valve to not waste steam.

 

[ghensky]

The steam is off a pressure relief valve taking place once or twice a year.

How to calculate the pressure loss, condensate amount, or velocity of steam in swirling motion in a gas liquid separator, any idea or resource suggestion?

 

[racookpe1978]

Fix the "why is it blowing" problem!

NO PRV should ever randomly release pressure while in operation. No process should need to use a PRV to "allow" failures as a part of your routine operating process "That's always what happens" type of excuse.

People die when that is allowed to happen.

 

[ghensky]

Racookpe1978, PRV itself is a "fix" to other potential catastrophe.
But that's a different topic and is not what I am looking for anyway.
Thanks for your insight.

 

[GenB]

Amount:collect condensate for a period. Ex pressure: a foot away from exit install a press gauge. Velocity: need a "velocimeter" don't you? Or a steam flow meter will do both.