Interpreting Surge Analysis Results

This paper details methods of interpreting maximum surge pressures in LNG pipelines due to valve closures and other transient events. The standard methodology for determining the onset of surge events and the pressure transients involved uses explicit integration; this method of analysis produces inherent “noise” in the solution results due to the integration method. The paper discusses methods of filtering data obtained through explicit integration and demonstrates which filters provide the best results for these analyses. Filtered and unfiltered results are presented for an actual LNG unloading facility subjected to a number of transient events, with discussion provided on determining the maximum peak pressures, their duration and the frequency content of secondary pressure waves.Copyright © 2007 by ASME