Hye All. I need your technical support regarding to adequacy check of exiting relief valve and also control valve. For information, the existing slug catcher undergoes retrofit (replacement of the internal part) for improving vapor liquid separation. The existing gas filter separator also has been upgraded with new filter (0.3 micron). My questions are:
- On what situation that we need to do adequacy check on the existing relief valve?? (Refer PSV 1, 2&3). Is it by having new flowrate (flowrate has been incresed)? Or the composition of the natural gas change? For me, let say the flowrate increased, the only relief valve that needs to be check is PSV 2 since the relief rate is based on actual flowrate. If we add the flowrate to some figure, the relief rate of the valve might be increased. For the fire case, even the flowrate has been increased, I think the relief valve size still maintain since the relief rate is based on expansion of the liquid inside the vessel of slug catcher and also Gas filter separator and the expansion of the liquid is based on wetted area exposed to the fire. So since the vessel is maintained, I conclude that the relief rates also maintain and the valve size is still maintained. Let say the composition of the gas only change (flowrate remain same), I think, no need to do adequacy check for all relief valve.
- It is expected the condensate flowrate increased after having retrofitting at slug catcher, and also due to evolution of feed gas composition (tends to being heavier). So for me, all the control valve need to be checked with new flowrate. If the flowrate increase not so significant, I think we can maintain the existing control valve isn’t?
Appreciate team to comment.
refer Doc1 for rough sketch. need further info pls ask,
Many Thanks