An energy company contacted ioMosaic to evaluate dynamically the stability of eight separate Seal Oil Pressure Relief Devices (PRDs) during a blocked outlet scenario because of pocketed outlet piping. The main challenge encountered during this project was to accurately estimate the acoustic velocities of the oil. The velocities were estimated based on a first order regression relating acoustic velocity, temperature, pressure and API gravity, established in the Ph.D. thesis titled “Wave Velocities in Hydrocarbons and Hydrocarbon Saturated Rocks – With Applications to EOR Monitoring” (Z. Wang, Stanford University, 1988).
The project was conducted using Process Safety Office® SuperChemsTM. The 1D dynamic analysis for each system was based on the following steps:
The deliverable for each system analyzed was a report illustrating the following results:
The analysis showed that the systems operate under stable manner and therefore, contingent upon the presence of appropriate drainage at the lowest point of the relief device discharge piping, these pressure relief systems can be considered to be consistent with Recognized and Generally Accepted Good Engineering Practices (RAGAGEPs), such as API Standard 520 Part II and ASME Section VIII.