2 replies to this topic

[uwaterloo]

Hi,

Purge gas is being injected into high pressure gas line prior to start up. During operations, there are 2 ball valves and 2 check valves that prevent the backflow of the high pressure gas into the purge line. However, there is also a PSV for extra safety on the purge gas line. I am wondering what what is basis to determine the relief rate.......initially I thought you would have to size the psv for entire load of the high pressure gas line..but I am told that this is incorrect....Please advise.

Thanks.

[Bobby Strain]

Whoever employs you, or your client, should have some criteria. And, the check valves should each be of a different design. If I were designing something like this, I would provide a dropout spool and physically disconnect the low pressure system. Connections like this are always risky business.

 

Bobby

[fallah]

 

Purge gas is being injected into high pressure gas line prior to start up. During operations, there are 2 ball valves and 2 check valves that prevent the backflow of the high pressure gas into the purge line. However, there is also a PSV for extra safety on the purge gas line. I am wondering what what is basis to determine the relief rate.......initially I thought you would have to size the psv for entire load of the high pressure gas line..but I am told that this is incorrect....Please advise.

 

 

Hi,

 

Without having the sketch of the system along with the adequate info in hand, it cannot be possible to submit the accurate response to such important safety issue...