Pressure relief valve (PRV) reaction force - Two phase fluid - Closed system

[Paldex]

Dear Members,

I am doing a stress analysis for PRV cases which release a two-phase fluid in a closed system (Flare). In API 520 Part-II, they provided the calculation for open system only not for closed system. But some big MNC's have developed some forumulas for the closed systetm. If you find it please share it. I am in need of it. Even in Pipe-mill software they provided the calculation for the single-phase closed system only.

[Grimm]

Hi,
perhaps you can use FlareNet to evaluate back pressure in your system. I think colculation that's given in API 520 Part2 with FlareNet calculations will more then enough for you strees analysis. The difference between closed and opened flare system is in overall influence on each spring of gas relieving with system's back pressure. If you design the close to reality (but not real of course) flare system in FlareNet with adequate parameters in springs (!) (PRVs) you will gain reliable results. In case when you can't find the exact formulas it's better to find bypass way out.

[vdain]

I would use ASME 31.1-2010 Power Piping Code Appendix II which provides the guidelines for the safety valve stress analysis in a closed discharge system.

Dear Members,

I am doing a stress analysis for PRV cases which release a two-phase fluid in a closed system (Flare). In API 520 Part-II, they provided the calculation for open system only not for closed system. But some big MNC's have developed some forumulas for the closed systetm. If you find it please share it. I am in need of it. Even in Pipe-mill software they provided the calculation for the single-phase closed system only.