3 replies to this topic

[Steve90]

Hi guys ;

 

I determined the discharge orifice area with hysys v8.8 ( the calculated area is equal to the result in API 520 example).

Trying to use pressure relief utility in Hysys v8.8 to Line size the inlet and the outlet tail pipes, i found that hysys uses these constraints :

 

Inlet pressure drop <3% Set pressure

outlet pipe avg velocity < 50 % of sonic velocity

outlet pipe exit < 90% of sonic velocity 

 

Since i'm new, i want to know if this is correct , because i read on this forum and internet that generally we use these constraints :

 

Inlet pressure drop <3% Set pressure

pressure drop < 10 % of set pressure (if conventional)

pressure drop < 50 % of set pressure (if balanced)

pressure drop < 100 % of set pressure (if pilot)

 

Mach number < 0.5 for gas

 

which one is correct ? 

 

Thx

[Bobby Strain]

Looks like you are doing lots of relief valve work. What you should do is search for good material on relief valves. We don't want to continue to do your work for you.

 

Bobby

[breizh]

Steve90,

You may find some interest reading the documents attached .

Hope this helps

Breizh

Edited by breizh, 30 December 2015 - 09:27 PM.

[Steve90]

Thank you very much Mr breizh for your valuable posts !! By the way happy new year ! wish u all the best !!