Sizing Rupture Disk Vent Line Systems for High-velocity Gas Flows
Abstract
In the chemical and petrochemical industry, vessels and pipes are protected against overpressure using safety relief devices, usually rupture disks (also called a bursting disc) or safety valves installed in a vent-line. Proper sizing of rupture disk vent-line system involves fluid dynamic coupling of the rupture disk device and the entire vent-line with all its fittings. Sizing requires correct consideration of the fitting’s and piping’s minor loss coefficients to determine of the pressure drop and dischargeable mass flow rate. A fitting’s minor loss coefficient is typically determined under low-velocity and incompressible flow. It is however not precisely applicable for all plausible flow cases that occur in practice especially for high-velocity compressible gas flow, two-phase flow, flashing liquids or multiphase service without proper consideration of compressibility. Experiments show that rupture disk irreversible pressure drop, determined assuming a constant minor loss coefficient, with current methods is underestimated by at least 30% for high-velocity compressible gas flow. This is because the compressibility is not accurately considered there and the pressure profile calculated this way is faulty. This work presents a scientific method to calculate the pressure profile and dischargeable mass flow rate in a vent-line system with a rupture disk installed seamlessly. The pipe and rupture disk loss coefficients are enhanced to factor compressibility fully. Experiments show that this method predicts the pressure profile along a vent-line with a rupture disk installed and the dischargeable mass flow rate better as compared to current methods. The method is applicable for both low- velocity and high-velocity compressible gas flow as is typically the case during pressure relief.
Description
PresentationSubject
Rupture diskCollections
Citation
Mutegi, Mondie K. (2018). Sizing Rupture Disk Vent Line Systems for High-velocity Gas Flows. Mary Kay O'Connor Process Safety Center; Texas &M University. Libraries. Available electronically from https : / /hdl .handle .net /1969 .1 /193473.