4 replies to this topic

Could someone help me calculate the relieving temperature of PSV.
PSV is on an acid KOD. OP-0.7 Kg/cm2g & OT=46 deg C. its mentioned in API that Relieving temp for gases is calculated as Tr=(Pr/P1)*T1.
but this law applies only for constant volume of gas. and in KOD considering Blocked outlet contigency we cant apply this law as no of moles of gas entering vessel inc with time.

[senthil13]

hello Puja,

i uses aspen hysys to overcome the same situation.. i was digging this issue for some times long back.. but one of my cleint solved it using the aspen hysys software.

I think you can do with aspen hysys..

If u r stuckup pls contact me..

[JoeWong]

This equation is ONLY for vessel contain GAS/VAPOR only. DO NOT USED for other scenario.

[CMA010]

This equation is ONLY for vessel contain GAS/VAPOR only. DO NOT USED for other scenario.

Small addition, it's valid for the fire scenario of vessels containing gas/vapour.

What is the high pressure source in this case?

[sheiko]

Could someone help me calculate the relieving temperature of PSV.
PSV is on an acid KOD. OP-0.7 Kg/cm2g & OT=46 deg C. its mentioned in API that Relieving temp for gases is calculated as Tr=(Pr/P1)*T1.
but this law applies only for constant volume of gas. and in KOD considering Blocked outlet contigency we cant apply this law as no of moles of gas entering vessel inc with time.

To determine the relieving temperature during a blocked gas outlet scenario, i would use the polytropic compression temperature (or, to simplify, the adiabatic compression temperature).