2 replies to this topic

[Steve90]

Hi guys !

 

for my knowldge i think that to design inlet and outlet tail pipes for psv we should consider these constraints :

- pressure drop  < 3% of set pressure  (inlet)

- pressure drop  <10% of set pressure  (outlet)

- Mach number > 0.3 ; Mach number > 0.7 when discharge to process

 

I want to know if this is true ?  

 

For Liquid phase there is no mach number ? so what can we use to determine the design ?

 

Can hysys calculate Mach number ? 

 

 

Thx

[serra]

it depends from applicable codes, however, as general rule 3% and 10% should give reasonable numbers,

see also the many discussions about this topic at cheresources forums,

with relatively high densities (see liquids) one should consider also stress, see NORSOK or similar standards,

finally, I think you can calculate speed of sound (and mach number) with most simulators,

for two-phase there are specific methods, see for example

"http://www.cheresour...rbons-mixture/"

[fallah]

Steve90,

 

For PSV inlet/outlet lines the mach no. should be limited below a reasonable value, say 0.6, not being unlimited as you mentioned!

 

Also, the static head in inlet lines of PSV's for liquid services is more important than the relevant friction loss...