2015 AIChE Spring Meeting and 11th Global Congress on Process Safety

(105c) Modeling and Computation of Reaction Forces on Relief Piping during Depressurization

Authors

Conzen, J. - Presenter, Fauske & Associates, LLC
Wood, G. - Presenter, Fauske & Associates, LLC
Modeling
and Computation of Reaction Forces on Relief Piping During Depressurization   Jens
Conzen Manager,
Structural Services & Vibration e-mail
address: conzen@fauske.com & Gabe
Wood Senior
Chemical Engineer e-mail
address: wood@fauske.com   Fauske & Associates, LLC, 16W070 83rd Street,
Burr Ridge, Illinois 60527, USA     ABSTRACT   The
sudden opening of a relief device, during an overpressure event, will cause the
relief piping to experience dynamic loads.  A pressure wave may be generated
that travels at the speed of sound through the fluid.  This has lead to force
imbalances, particularly on long pipe segments, that can potentially damage the
relief system, or prevent the relief system from operating properly.  In order
to design and properly protect the relief piping with the necessary supports,
it is critical that a detailed analysis of the dynamic loads (e.g. thrust,
momentum and wave), following the opening of a pressure relief device, is
performed.  In many cases, simple analytical techniques may not be appropriate,
and a time history analysis of the loads acting on the relief system may be
required.  To address this phenomenon, an evaluation of the dynamic loads using
RELAP5 (Reactor Excursion and Leak Analysis Program) software will be
discussed.  The RELAP5 software can be used to analyze fluid transients and
compute resulting loads.  It is possible to evaluate systems undergoing single
phase or two phase relief.