Flash_Drum_Dynamic_Simulations.pdfVIP

1 - Classification: Internal 2013-03-01 SLUGGING IN A FLARE HEADER Dynamic simulation of Crude Flash Drum when blocking outlets during operation Runar S?ther (TEX Stavanger) Leif Ernstsen (AkerSolutions) 2 - Classification: Internal 2013-03-01 Content of Presentation ? System description ? Simulation tools ? The OLGA model ? Simulated scenario ? Simulation technical challenges ? Calculation of forces in pipe bends ? Results ? OLGA volume errors: How to avoid them – How to filter them off ? Concluding remarks 3 - Classification: Internal 2013-03-01 3D Model of Sture Plant Flash Drum Flare Header 4 - Classification: Internal 2013-03-01 System Sketch To compressor Un-stabilized oil cavern To flare Flare header PSV, SP = 5 barg Flash Drum VA20300 Crude Oil Loading Pumps Rupture disc, SP = 7 barg PC SP= 1.5 barg Gas outlet 5 - Classification: Internal 2013-03-01 The Crude Oil Flash Drum 6 - Classification: Internal 2013-03-01 System Description One of the Sture caverns. Length 314 m, height 33 m, width 19 m. Capacity ~ 160 000 m3 View showing part of 24 inch Flare Header with expansion loop 7 - Classification: Internal 2013-03-01 Simulation Tools ? HYSYS V7.1, Static and Dynamic - for defining fluid - for heat exchanger dynamics ? Flarenet V7.1 - for examining previous modelling work ? PVTsim 17.0.0 - for PVT file generation for OLGA ? OLGA 5.3.4.4 with precalculated fluid file - for dynamic modelling of upset scenario 8 - Classification: Internal 2013-03-01 OLGA Model Elevations 9 - Classification: Internal 2013-03-01 Blocked Outlet Scenario ? Normal operation ? Upset start: Control system error or stop of Flash Drum pump ? Flash Drum liquid outlet closes ? Flash Drum primary protection (HH liq.) fails ? Puts demand on secondary protection (PSV, RD) ? Full Flash Drum ? Compressor trip ? Gas outlet blocked ? PSV opens at 5 barg ? Fully open at 5.5 barg ? RD opens at 7 barg ? Multiphase liquid and gas flow through Flare Header ? Slugging ? Simulation run for 15 minutes af