Vulture860
Mechanical
- Oct 25, 2012
- 7
I'm looking for information on dynamic analysis requirements for flare system header piping, looking at this from a pipe stress standpoint.
I'm looking at a flare line header pipe DOWNSTREAM of the main knockout drum, so my assumption is that I'm only looking at gas flow in this specific header piping (not 2-phase flow, not assuming a slug of liquid in the system). I haven't found any literature stating requirements for dynamic analysis on this specific portion of the flare system, not sure if guidelines even exist. I can completely understand the need for dynamic analysis of the individual safety valve discharge piping systems tying into the header upstream of the knock-out drum, that makes sense to me.
I've actually been questioned as to whether dynamic analysis is even required for this section of piping, which I'm starting to wonder myself. Our design case, given by customer's process group, is assuming a plant wide power outage (large # of safeties blowing at same time) resulting in a huge instantaneous flow rate at a given operating pressure. However, it seems that a true 'instantaneous' flow of all these safeties at the given pressure and flow rate will never truly occur, even under the plant wide outage, considering how far away each of the safety valves are from each other (spread throughout the plant, different sizes, different outlet pipe sizes, different flows, etc).
Just wondering if anyone experience to share with this type of design. Thanks.
I'm looking at a flare line header pipe DOWNSTREAM of the main knockout drum, so my assumption is that I'm only looking at gas flow in this specific header piping (not 2-phase flow, not assuming a slug of liquid in the system). I haven't found any literature stating requirements for dynamic analysis on this specific portion of the flare system, not sure if guidelines even exist. I can completely understand the need for dynamic analysis of the individual safety valve discharge piping systems tying into the header upstream of the knock-out drum, that makes sense to me.
I've actually been questioned as to whether dynamic analysis is even required for this section of piping, which I'm starting to wonder myself. Our design case, given by customer's process group, is assuming a plant wide power outage (large # of safeties blowing at same time) resulting in a huge instantaneous flow rate at a given operating pressure. However, it seems that a true 'instantaneous' flow of all these safeties at the given pressure and flow rate will never truly occur, even under the plant wide outage, considering how far away each of the safety valves are from each other (spread throughout the plant, different sizes, different outlet pipe sizes, different flows, etc).
Just wondering if anyone experience to share with this type of design. Thanks.