API says that the pressure drop in the inlet piping to PSVs shall not exceed 3% of the set pressure. Common sense also gives that there should be no pockets in the inlet piping (as liquid accumulation would promote corrosion, possible water hammer effect and possible blockage if solids are...
Thanks for your reply, chemebabak. This is for an FPSO, and I agree with you that economy shall not govern our choice. That said, it shouldn't be a problem to optimize the design, as long as we can prove that the pressure loss will be low enough.
I am reviewing a system , and the engineer has...
Does anybody know if there are rules to where the manual valves should be placed around a PSV? "Inside" the reducers or "outside"? What I mean is that there would be a (significant) difference in manual valve size whether we place them close to the PSV's, upstream and downstream, where the pipe...
chemebabak: then I am very relieved (oh, yes) - my consideration was that, since the vessel could see 10 bar in the flare system, the pressure inside the vessel could build up to 10 bar. Superimposed from the flare system! But since it is completely independent, I assume the PSV acts as a non...
Thanks MJCronin, I have read a few standards on this and believe I have a fair understanding of the subject MAWP/design pressure - I was searching for a more philosophical approach perhaps; that the flare system determines the design pressure of a vessel.
And it must be so, the flare system may...
A short question:
I'm considering design pressure of various vessels in an oil&gas utility system. The vessel in question is protected by a pair of PSV's which relieves to flare. The flare system has a design pressure of 10 bar. Should the vessel's design pressure be set to the same pressure...
We have had a Hazop on the system, but the isolation issue didn't come up until later as a client request.
BigInch: You say: "If I was doing this, I would place a PSV set at 275 psig right after the min FCV. That would place the PSV actually on the high pressure piping between the FCV and the...
The vessel, and therefore the piping downstream the flow valve, is today protected by a PSV. The block and bleed valves are retrofit work and I hoped to be able to use 150# valves provided they were kept in a locked open position by a key lock system. They would then never be closed without a...
A minimum flow from a high pressure pump back to a low pressure vessel is controlled with a minimum flow valve. This pressure loss over the valve is 90 bar. Upstream the valve we have #1500 piping class and downstream it will be #150. We have a spec break over the valve.
Now, we need double...
Thanks all.
I've checked a fire case and two tubes (flow from both ends of each tube)and last, the energy input from the steam, as Tamer123 pointed out.
There is necessary to protect both sides, yes. But from what?
Tube side is protected by a PSV, in the event of a blocked outlet and running pumps.
Shell side shall be protected against tube failure. Bursting of two tubes actually.
Question is, do I need to examine two events -
i)failure of...
Thanks for your reply, gerhardl.
a) the steam is what is available on the plant
b) question is: do we need both PSV and burst disk? Is the water/glycol likely (i.e can it happen) to be heated by the steam so it'll exceed design pressure of the heat exchanger?
I'm working on project where LNG shall be gasified. To achieve this, we use a shell&tube heat exchanger to heat the pressurized LNG from -155 degC to 10 degC, where the natural gas is in gaseous state. The LNG is on the tube side of the exchanger.
On the shell side we use a water/glycol mix as...
