[Genii]

Dear All,

1. Can PSV outlet line reach sonic velocity???

2. And is that correct that API suggests that Inlet line pressure drop should be 3% of set pressure and outline line pressure drop should not create backpressure more than 10% of the set pressure??

3. A PSV orifice designation has more than one inlet outlet sizes; What is the criteria or basis of selecting particular inlet outlet size for a specific designation??

Best Regards,
Genii

[mbeychok]

Genii:

In answer to your questions:

(1) Yes, the linear velocity (i.e., m/s) of the gas can reach sonic velocity in the PSV. See the posting on "Choked Flow" in this thread at http://www.chemicalforums.com/index.php?topic=8910.0

(2) and (3): I strongly recommend that you register on the online forum at http://www.cheresources.com/invision/index.php?showforum=4 and ask your questions at the "Relief Devices Forum" at that site.