Design of Discharge Piping for Pressure Relief Systems

The ASME Boiler and Pressure Vessel Code and publications by many manufacturers caution the design engineer to consider back pressure in discharge piping when sizing and selecting pressure relief valves. Only general guidelines are given, however, because of widely varying installation requirements. This paper addresses manifolded discharge piping system design. The method of analysis provides a simple technique for determining pressure within a discharge piping system. The method is based on adiabatic flow and uses local Mach number to relate expansion of the gas in the pipes to a mass flow function. The paper illustrates that relief valves discharging into lines and headers should not be sized or selected without careful analysis of the entire relief system.

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Testing and Modeling of an Acoustic Instability in Pilot-Operated Pressure Relief Valves

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.4031623 ◽

2015 ◽

Vol 138 (5) ◽

Cited By ~ 6

Author(s):

Timothy C. Allison ◽

Klaus Brun

Keyword(s):

Dynamic Instability ◽

Essential Element ◽

Dynamics Simulation ◽

Piping System ◽

Pressure Relief ◽

Simulation Code ◽

Acoustic Instability ◽

Process Gas ◽

Piping Systems ◽

Pressure Relief Valves

Pressure relief valves (PRVs) are included as an essential element of many compressor piping systems in order to prevent overpressurization and also to minimize the loss of process gas during relief events. Failure of the valve to operate properly can result in excessive quantities of vented gas and/or catastrophic failure of the piping system. Several mechanisms for chatter and instability have been previously identified for spring-loaded relief valves, but pilot-operated relief valves are widely considered to be stable. In this paper, pilot-operated PRVs are shown to be susceptible to a dynamic instability under certain conditions where valve dynamics couple with upstream piping acoustics. This self-exciting instability can cause severe oscillations of the valve piston, damaging the valve seat, preventing resealing, and possibly causing damage to attached piping. Two case studies are presented, which show damaging unstable oscillations in a field installation and a blowdown rig, and a methodology is presented for modeling the instability by coupling a valve dynamic model with a 1D transient fluid dynamics simulation code. Modeling results are compared with measured stable and unstable operation in a blowdown rig to show that the modeling approach accurately predicts the observed behaviors.

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A Novel Adiabatic Pipe Flow Equation for Ideal Gases

Journal of Fluids Engineering ◽

10.1115/1.4005679 ◽

2012 ◽

Vol 134 (1) ◽

Cited By ~ 1

Author(s):

Jung Seob Kim ◽

Navneet Radheshyam Singh

Keyword(s):

Pressure Drop ◽

Mass Flux ◽

Pipe Flow ◽

Flow Equation ◽

Average Density ◽

Pressure Relief ◽

Pipe Length ◽

Adiabatic Flow ◽

Relief System ◽

Common Application

Compressible flow involves variation in the density with changes in pressure and temperature along the pipe length. This article revisits the conventional adiabatic pipe flow equation and finds a fundamental drawback in this equation. The corrected adiabatic pipe flow equation has fixed the fundamental error in the conventional adiabatic pipe flow equation where the average density estimation for the conventional adiabatic equation is lower than the lower bound of the average density based on isothermal temperature. However, both the conventional adiabatic equation and the corrected adiabatic equation result in an over prediction of mass flux due to a deficiency in the average density definition. The over prediction of mass flux is not significant if the pressure drop is less than 40%; however, the pressure drop is usually greater than 40% of the inlet pressure for most pressure relief system applications. The authors offer a novel adiabatic pipe flow equation based on insights presented in this work. The novel adiabatic pipe flow equation is the most suitable solution for the pressure relief system applications as well as any other common application since it better represents the nature of adiabatic flow in a pipe. The experimental data previously published is compared with the predictions to validate the new adiabatic pipe flow model.

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Testing and Modeling of an Acoustic Instability in Pilot-Operated Pressure Relief Valves

Volume 9: Oil and Gas Applications; Supercritical CO2 Power Cycles; Wind Energy ◽

10.1115/gt2015-43797 ◽

2015 ◽

Author(s):

Timothy C. Allison ◽

Klaus Brun

Keyword(s):

Dynamic Instability ◽

Essential Element ◽

Dynamics Simulation ◽

Piping System ◽

Pressure Relief ◽

Simulation Code ◽

Acoustic Instability ◽

Process Gas ◽

Piping Systems ◽

Pressure Relief Valves

Pressure relief valves are included as an essential element of many compressor piping systems in order to prevent overpressurization and also to minimize the loss of process gas during relief events. Failure of the valve to operate properly can result in excessive quantities of vented gas and/or catastrophic failure of the piping system. Several mechanisms for chatter and instability have been previously identified for spring-loaded relief valves, but pilot-operated relief valves are widely considered to be stable. In this paper, pilot-operated pressure relief valves are shown to be susceptible to a dynamic instability under certain conditions where valve dynamics couple with upstream piping acoustics. This self-exciting instability can cause severe oscillations of the valve piston, damaging the valve seat, preventing resealing and possibly causing damage to attached piping. Two case studies are presented that show damaging unstable oscillations in a field installation and a blowdown rig, and a methodology is presented for modeling the instability by coupling a valve dynamic model with a 1-D transient fluid dynamics simulation code. Modeling results are compared with measured stable and unstable operation in a blowdown rig to show that the modeling approach accurately predicts the observed behaviors.

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Building valves. Combined temperature and pressure relief valves. Tests and requirements

10.3403/02106180 ◽

2000 ◽

Keyword(s):

Pressure Relief ◽

Pressure Relief Valves ◽

Temperature And Pressure

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LPG equipment and accessories. Pressure relief valves for transportable refillable cylinders for Liquefied Petroleum Gas (LPG)

10.3403/30265335 ◽

2015 ◽

Keyword(s):

Liquefied Petroleum Gas ◽

Pressure Relief ◽

Pressure Relief Valves

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Geotextile encased columns (GEC) used as pressure-relief system. Instrumented bridge abutment case study on soft soil

Geotextiles and Geomembranes ◽

10.1016/j.geotexmem.2017.02.003 ◽

2017 ◽

Vol 45 (3) ◽

pp. 227-236 ◽

Cited By ~ 6

Author(s):

F. Schnaid ◽

D. Winter ◽

A.E.F. Silva ◽

D. Alexiew ◽

V. Küster

Keyword(s):

Soft Soil ◽

Pressure Relief ◽

Bridge Abutment ◽

Relief System

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Dynamic Behavior of Transportation Pressure Relief Valves Under Simulated Fire Impingement Conditions

Journal of Pressure Vessel Technology ◽

10.1115/1.556151 ◽

1999 ◽

Vol 122 (1) ◽

pp. 60-65 ◽

Cited By ~ 2

Author(s):

A. J. Pierorazio ◽

A. M. Birk

Keyword(s):

Dynamic Testing ◽

Test Facility ◽

Time Varying ◽

Relief Valve ◽

Pressure Relief ◽

Flow Rates ◽

Depth Analysis ◽

Pressure Relief Valves ◽

Accident Conditions ◽

Insight Into

This paper presents the results of the first full test series of commercial pressure relief valves using the newly constructed Queen’s University/Transport Canada dynamic valve test facility (VTF) in Maitland, Ontario. This facility is unique among those reported in the literature in its ability to cycle the valves repeatedly and to measure the time-varying flow rates during operation. This dynamic testing provides much more insight into valve behavior than the single-pop or continuous flow tests commonly reported. The facility is additionally unique in its simulation of accident conditions as a means of measuring valve performance. Specimen valves for this series represent 20 each of three manufacturers’ design for a semi-internal 1-in. 312 psi LPG relief valve. The purpose of this paper is to present the procedure and results of these tests. No effort is made to perform in-depth analysis into the causes of the various behaviors, nor is any assessment made of the risk presented by any of the valves. [S0094-9930(00)01201-4]

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