Dear all,
For a PSV in steam service, we have an operating pressure of 46 barg and a set pressure of 50.6 barg (coincident with MAWP). One supplier indicated that the op. pressure shall be reduced to 45.5 barg, to allow a required gap of 10% between operating and set pressure.
We cannot modify the operating pressure nor the set pressure (since is equal to the MAWP). My question is: assuming an op. pressure of 46 barg, at some stages of the closing travel we will have pressure lesser than 45.5 barg at PSV's disc, due to the dP in the inlet piping (near 2.4% at rated flow). This disc pressure will increase while flow decrease, up to 46 barg. But, the PSV will be already closed. So, for the reclosing (without seen others effects that could excert to have closer oper./design pressure), could I be confident that there will be not issues?
Thanks!