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Guibing Zhao - One of the best experts on this subject based on the ideXlab platform.
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An easy method to design gas/vapor relief system with Rupture disk
Journal of Loss Prevention in The Process Industries, 2015Co-Authors: Guibing ZhaoAbstract:Tank discharge gas/vapor flow problems are frequently encountered in both practice and design. To perform this type of design calculation, the first step is to identify whether the flow is choked or not through a trial-and-error solution of an equation for adiabatic flow with friction from a reservoir through a pipe. Developing a direct method without any trial-and-error to identify a choking condition would be helpful for expediting the flow calculations. This paper presents an easy and quick method to identify the choking of gas flow for an emergency relief system consisting of a Rupture disk and vent piping. This greatly simplifies the design calculations. The proposed method for validating the venting adequacy of existing ERS circumvents the iteration calculation and the use of Lapple charts. Three case studies for the design of vent piping for Rupture Disks support the proposed method. © 2015 Elsevier Ltd. All rights reserved. Emergency Relief Systems (ERS) are installed to protect process vessels from the catastrophic effects of excessive overpressure and subsequent Rupture. An Emergency Relief System can be thought of as being composed of three different elements: pressure source (reservoir), relief device, and vent line. The pressure source can be a reactor, a pipe needing to be protected, or any other equipment or process vessel. Rupture Disks and safety valves are the primary relief devices by which pressurized vessels and pipelines are protected against intolerable overpressures. The safety valve is a reclosing pressure relief device that will reclose once the protectedsystem pressure is lower than the set pressure of the valve, minus the “blowdown” of the valve. The blowdown of a safety valve is the difference between the set pressure and the closing pressure of a safety valve, expressed as a percentage of the set pressure. The Rupture disk is a non-reclosing pressure relief device actuated by the differential pressure between the inlet and outlet sides of the disk, and it is designed to function by bursting. The methods for designing gas/vapor emergency relief system have been well established and used in industrial practice (API
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An easy method to design gas/vapor relief system with Rupture disk
Journal of Loss Prevention in the Process Industries, 2014Co-Authors: Guibing ZhaoAbstract:Tank discharge gas/vapor flow problems are frequently encountered in both practice and design. To perform this type of design calculation, the first step is to identify whether the flow is choked or not through a trial-and-error solution of an equation for adiabatic flow with friction from a reservoir through a pipe. Developing a direct method without any trial-and-error to identify a choking condition would be helpful for expediting the flow calculations. This paper presents an easy and quick method to identify the choking of gas flow for an emergency relief system consisting of a Rupture disk and vent piping. This greatly simplifies the design calculations. The proposed method for validating the venting adequacy of existing ERS circumvents the iteration calculation and the use of Lapple charts. Three case studies for the design of vent piping for Rupture Disks support the proposed method.
Jens Denecke - One of the best experts on this subject based on the ideXlab platform.
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Sizing Rupture disk vent line systems for high-velocity gas flows
Journal of Loss Prevention in The Process Industries, 2019Co-Authors: Mondie Kimandi Mutegi, Jürgen Schmidt, Jens DeneckeAbstract: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. Pressure drop and dischargeable mass flow rate through a safety device must be determined. This should be done with correct consideration of the fittings relieving area and the fitting's loss coefficient, which depend on flow conditions upstream of Rupture disk device. Sizing of Rupture disk relief systems should also consider flow contraction caused by the Rupture disk device as this contraction limits flow through the device. This work presents a scientific method to calculate the pressure profile in a vent-line system with a Rupture disk installed with the Rupture disk zero-velocity minor loss coefficient, KRD,0. This proposed characteristic number is determined experimentally and taken to be constant for a Rupture disk type, and nominal pipe size. The Rupture disk losses are enhanced to factor compressibility fully. The pressure drop across a Rupture disk and the pressure profile in a Rupture disk relief line are predicted seamlessly for low-to high-velocity gas flows and validated experimentally. A new test-section equipped with state-of-the-art instrumentation is used to deliver precise experimental data. Experiments show that this method predicts the pressure profile along a vent-line with a Rupture disk installed with less uncertainty as compared to classic methods. The method is applicable for both low-velocity and high-velocity compressible gas flow as is typically the case during pressure relief in a complex Rupture disk relief line.
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Challenges in Sizing Rupture Disk Vent Line Systems Especially for Compressible Two-phase Flow
Chemical engineering transactions, 2016Co-Authors: Kimandi Mutegi Mondie, Jürgen Schmidt, Jens DeneckeAbstract: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. In contrast to a safety valve, the opening of a bursting disk is a stochastic process leading to a certain range of flow areas, depending on the manufacturing process of the disc. In general, this area cannot be predicted to the last percent. It determines dominantly the overall pressure loss and, in case of critical flow, the mass flow rate to be discharged through a bursting disk vent line system. To date, tests to determine the Rupture disk flow resistance factor are typically performed with low velocity, subcritical, almost incompressible flow with air, nitrogen and water. Test conditions are stationary flow despite the fact that the flow regime during emergency relief varies from liquid only, gas only, gas/liquid two-phase flow or even flashing liquids. Even though a Rupture disk is used as a primary relief device, the Rupture disk flow resistance coefficients are not precisely applicable for compressible gas, vapor liquid or multiphase service (Friedel & Kisner, 1988). For two-phase flow, there is neither a standardized test section, nor any reliable test results available. Consequently, there is also no precise model to size a Rupture disk device in these cases (Schmidt & Claramunt, 2014). Additionally, for typical industrial Rupture disk vent-line systems, significant errors can be made by applying current sizing methods (Schmidt, 2015). Over-dimensioning the Rupture disk vent line system leads to unnecessary financial costs and may cause malfunction of the collecting systems downstream when the fluids discharged are more than the design limits. Under-dimensioning may lead to hazardous incidents with loss of human life and equipment. There is a strong need for experimental data and a reliably validated sizing method that is valid for single-phase compressible gas as well as for flashing and non-flashing two-phase flow.
Sara Claramunt - One of the best experts on this subject based on the ideXlab platform.
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sizing of Rupture Disks for two phase gas liquid flow according to hne cse model
Journal of Loss Prevention in The Process Industries, 2016Co-Authors: Juergen Schmidt, Sara ClaramuntAbstract:Abstract Industrial Rupture disk vent line areas for two-phase flow are currently overestimated. As a consequence, the dischargeable mass flow rate is partially much higher than necessary often leading to malfunctions in downstream retention systems and increased environmental loads. For two-phase gas/liquid flow there is no standardized sizing procedure available. Hence, the homogeneous non-equilibrium model HNE-DS is transferred from sizing safety valves to a procedure for sizing Rupture disk vent lines. Thermodynamic non-equilibrium effects like boiling delay are considered. The extend method is called HNE-CSE method. Characteristic numbers of Rupture disk vent lines like the resistance coefficient KR are typically measured under laboratory, subcritical conditions with incompressible fluids, i.e. liquids or gases at very low velocities. In contrast, the flow typically encountered in an industrial Rupture disk vent line is a compressible gas or two-phase gas/liquid flow under critical flow conditions. The sizing of a Rupture disk vent line based on characteristics for incompressible fluids is therefore a challenge. An appropriate test section for compressible fluids as an extension of ASME PTC25 is recommended. In addition the definition of the resistance coefficient is extended to compressible fluid flows.
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Sizing of Rupture Disks for two-phase gas/liquid flow according to HNE-CSE-model
Journal of Loss Prevention in The Process Industries, 2016Co-Authors: Juergen Schmidt, Sara ClaramuntAbstract:Abstract Industrial Rupture disk vent line areas for two-phase flow are currently overestimated. As a consequence, the dischargeable mass flow rate is partially much higher than necessary often leading to malfunctions in downstream retention systems and increased environmental loads. For two-phase gas/liquid flow there is no standardized sizing procedure available. Hence, the homogeneous non-equilibrium model HNE-DS is transferred from sizing safety valves to a procedure for sizing Rupture disk vent lines. Thermodynamic non-equilibrium effects like boiling delay are considered. The extend method is called HNE-CSE method. Characteristic numbers of Rupture disk vent lines like the resistance coefficient KR are typically measured under laboratory, subcritical conditions with incompressible fluids, i.e. liquids or gases at very low velocities. In contrast, the flow typically encountered in an industrial Rupture disk vent line is a compressible gas or two-phase gas/liquid flow under critical flow conditions. The sizing of a Rupture disk vent line based on characteristics for incompressible fluids is therefore a challenge. An appropriate test section for compressible fluids as an extension of ASME PTC25 is recommended. In addition the definition of the resistance coefficient is extended to compressible fluid flows.
Steve J. Hensel - One of the best experts on this subject based on the ideXlab platform.
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Analysis of Venting of a Resin Slurry
Journal of Pressure Vessel Technology-transactions of The Asme, 2018Co-Authors: James E. Laurinat, Steve J. HenselAbstract:A resin slurry venting analysis was conducted to address safety issues associated with overpressurization of ion exchange columns used in the Purex process at the Savannah River Site (SRS). If flow to these columns were inadvertently interrupted, an exothermic runaway reaction could occur between the ion exchange resin and the nitric acid used in the feed stream. The nitric acid-resin reaction generates significant quantities of noncondensable gases, which would pressurize the column. To prevent the column from rupturing during such events, Rupture Disks are installed on the column vent lines. The venting analysis models accelerating rate calorimeter (ARC) tests and data from tests that were performed in a vented test vessel with a Rupture disk. The tests showed that the pressure inside the test vessel continued to increase after the Rupture disk opened, though at a slower rate than prior to the Rupture. Calculated maximum discharge rates for the resin venting tests exceeded the measured rates of gas generation, so the vent size was sufficient to relieve the pressure in the test vessel if the vent flow rate was constant. The increase in the vessel pressure is modeled as a transient phenomenon associated with expansion of the resin slurry/gas mixture more » upon Rupture of the disk. It is postulated that the maximum pressure at the end of this expansion is limited by energy minimization to approximately 1.5 times the Rupture disk burst pressure. The magnitude of this pressure increase is consistent with the measured pressure transients. The results of this analysis demonstrate the need to allow for a margin between the design pressure and the Rupture disk burst pressure in similar applications. « less
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Analysis of Venting of a Resin Slurry
Volume 7: Operations Applications and Components, 2012Co-Authors: James E. Laurinat, Steve J. HenselAbstract:A resin slurry venting analysis was conducted to address safety issues associated with overpressurization of ion exchange columns used in the Purex process at the Savannah River Site (SRS). If flow to these columns were inadvertently interrupted, an exothermic runaway reaction could occur between the ion exchange resin and the nitric acid used in the feed stream. The nitric acid-resin reaction generates significant quantities of noncondensable gases, which would pressurize the column. To prevent the column from rupturing during such events, Rupture Disks are installed on the column vent lines. The venting analysis models accelerating rate calorimeter (ARC) tests and data from tests that were performed in a vented test vessel with a Rupture disk. The tests showed that the pressure inside the test vessel continued to increase after the Rupture disk opened, though at a slower rate than prior to the Rupture. Calculated maximum discharge rates for the resin venting tests exceeded the measured rates of gas generation, so the vent size was sufficient to relieve the pressure in the test vessel if the vent flow rate was constant. The increase in the vessel pressure is modeled as a transient phenomenon associated with expansion of the resin slurry/gas mixture upon Rupture of the disk. It is postulated that the maximum pressure at the end of this expansion is limited by energy minimization to approximately 1.5 times the Rupture disk burst pressure. The magnitude of this pressure increase is consistent with the measured pressure transients. The results of this analysis demonstrate the need to allow for a margin between the design pressure and the Rupture disk burst pressure in similar applications.
Juergen Schmidt - One of the best experts on this subject based on the ideXlab platform.
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sizing of Rupture Disks for two phase gas liquid flow according to hne cse model
Journal of Loss Prevention in The Process Industries, 2016Co-Authors: Juergen Schmidt, Sara ClaramuntAbstract:Abstract Industrial Rupture disk vent line areas for two-phase flow are currently overestimated. As a consequence, the dischargeable mass flow rate is partially much higher than necessary often leading to malfunctions in downstream retention systems and increased environmental loads. For two-phase gas/liquid flow there is no standardized sizing procedure available. Hence, the homogeneous non-equilibrium model HNE-DS is transferred from sizing safety valves to a procedure for sizing Rupture disk vent lines. Thermodynamic non-equilibrium effects like boiling delay are considered. The extend method is called HNE-CSE method. Characteristic numbers of Rupture disk vent lines like the resistance coefficient KR are typically measured under laboratory, subcritical conditions with incompressible fluids, i.e. liquids or gases at very low velocities. In contrast, the flow typically encountered in an industrial Rupture disk vent line is a compressible gas or two-phase gas/liquid flow under critical flow conditions. The sizing of a Rupture disk vent line based on characteristics for incompressible fluids is therefore a challenge. An appropriate test section for compressible fluids as an extension of ASME PTC25 is recommended. In addition the definition of the resistance coefficient is extended to compressible fluid flows.
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Sizing of Rupture Disks for two-phase gas/liquid flow according to HNE-CSE-model
Journal of Loss Prevention in The Process Industries, 2016Co-Authors: Juergen Schmidt, Sara ClaramuntAbstract:Abstract Industrial Rupture disk vent line areas for two-phase flow are currently overestimated. As a consequence, the dischargeable mass flow rate is partially much higher than necessary often leading to malfunctions in downstream retention systems and increased environmental loads. For two-phase gas/liquid flow there is no standardized sizing procedure available. Hence, the homogeneous non-equilibrium model HNE-DS is transferred from sizing safety valves to a procedure for sizing Rupture disk vent lines. Thermodynamic non-equilibrium effects like boiling delay are considered. The extend method is called HNE-CSE method. Characteristic numbers of Rupture disk vent lines like the resistance coefficient KR are typically measured under laboratory, subcritical conditions with incompressible fluids, i.e. liquids or gases at very low velocities. In contrast, the flow typically encountered in an industrial Rupture disk vent line is a compressible gas or two-phase gas/liquid flow under critical flow conditions. The sizing of a Rupture disk vent line based on characteristics for incompressible fluids is therefore a challenge. An appropriate test section for compressible fluids as an extension of ASME PTC25 is recommended. In addition the definition of the resistance coefficient is extended to compressible fluid flows.
