Overpressure protection evaluations for choke collapse or inadvertent valve openings are two of the relief incidents to design for according to API Standard 521 (Pressure-relieving and Depressuring Systems).
At BPT, we’ve in cooperation with our clients, developed an efficient methodology to capture these dimensioning incident scenarios without resorting to overly conservative assumptions that can drive up project costs. The key to obtain realistic results, is to fully understand the physics of the system. Careful analysis of results from flow simulations taking into account the balancing effect of forces in neighboring bends, makes it possible to use significantly more realistic slug loads than simply using maximum momentum changes is a common method.
This API standard also recommends that "slug loads" from the same incidents are considered for piping, pipe supports as well as equipment like the inlet separators. That is, design the topside inlet arrangement for the impact of liquid slugs during start-up where the liquid slugs are propelled by high-pressure gas from subsea tie-backs.
The most critical cases typically involve small liquid accumulations in low points combined with high gas pressure (maximum pipeline packing). Simulating these conditions and assessing their mechanical effects on topside piping, piping supports, and equipment nozzles are essential for reliable, safe system design.
By integrating dynamic flow modeling with OLGA and UniSim/HYSYS, and combining this with mechanical load analysis in Triflex using Promech Engineering’s expertise, we deliver rigorous, practical solutions/verifications — ensuring operational safety while avoiding unnecessary overdesign.
Promech Engineering is a specialized engineering and consultancy services covering piping and other pressure containing equipment and associated mechanical systems. Piping flexibility- and pipe stress analysis. Finite elements analysis. 3rd party verifications.
Billington Process Technology (BPT) is an independent digital solution, simulation and service company with Headquarter outside Oslo, Norway. BPT has unique domain knowledge within production and process facilities. We are world-class users of process simulators, and among the specialties are compressor design as well as process safety. The BPT Digital Production Twin includes an unmatched solution for holistic sensor-correction providing invaluable data fundament for a number of advanced digital applications (ala machine learning) as well as calibrated steady-state and dynamic simulators for efficient production optimization. BPT is a frontrunner in modernizing field development approach together with innovating oil companies. A BPT specialty is to apply integrated multiphase flow and dynamic process simulators throughout the field development, commissioning, and life of field to validate and improve design as well as troubleshoot and perform production optimization.
Please contact Knut Erik Spilling (kes@bpt.no) for more information.