As discussed above, the sensor itself constrains the sampling rate. After a short time, the hydrogen fire self-extinguished without further incident. The lessons learned are 1) to post signage indicating that no water is to be sprayed on the vent stack, and 2) to install a backup pressure-relief vent stack in case the main vent stack fails. The pressure rating of the burst disk should be sufficiently above the intended hydrogen system operating pressure to prevent premature failure. The burst causes were investigated. The majority of the pressure-related safety event records in the H2Incidents.org database involve burst disks. 5 below: The flow area calculated is known as the Minimum Net Flow Area (MNFA). Some involved failures from multiple pressure-relief events. Then, how do you tell when the tank is full? Attributing the bursting of a rupture disc to "premature failure" exemplifies this. Copyright 2012-2013 Inspection-for-Industry.Com, Rupture Disc Mill test reports for body and trim, Rupture Disc Checking of Characteristics (Effective Pressure, Disc Diameter ), Rupture Disc Performance including set pressure test, Rupture Disc Final visual / Dimension Inspection, Rupture Disc Documentation review prior to release(Final activity of Technical Inspection). P. Smith, R. W. Zappe, Rupture discs, in: Valve Selection Handbook (5th Edition), Gulf Professional Publishing, Houston, 2004, pp.227-267. These usually are physically or mechanically responsive and require no power or intervention to activate. It was built, and is maintained, by the Pacific Northwest National Laboratory with funding from the DOE Office of Energy Efficiency and Renewable Energy's Hydrogen and Fuel Cell Technologies Office. When a safety device activates, in our experience its useful to assume it worked as intended and then follow that logical assumption to its conclusions. Join today to get all of CHEMICAL ENGINEERING, Chemical Engineering news and content delivered every week, Access Intelligence, LLC. The sensor. There is no one, right answer regarding replacement frequency, but common considerations include the following: Severity: What is the severity of the service the rupture disc is subjected to? A mechanic working under the tube trailer was slightly injured when the loud noise from the burst disk rupture caused him to bump into the trailer several times while quickly exiting the area. This clamping load is affected by the torque applied to the studs, the type of lubrication on the studs, the type of flange gaskets used, and the general alignment of the pipe flanges. A burst disk (or rupture disk) is a common pressure-relief device that is designed to break at a predetermined pressure. Subsequent investigation found that the alloy 600 nickel-chromium-iron material on the burst disk failed at pressures below the design specification, indicating that the material is adversely affected by exposure to the combination of stresses and hydrogen. LDPE | Pressure Relief | Applications | REMBE GmbH Burst disk and associated vent system maintenance and inspection were inadequate. 6) below shows three main cases of rupture disc applications. The hydrogen gas was shut off and vented per normal procedures without further incident. In the following cases, they can be preferred as a primary relief option over pressure relief devices: The combined use of a ruptured disc along with pressure relief valves is becoming more popular within industries nowadays. Threads lubricated with high performance lubricants, such as PTFE, moly-disulfide or graphite, may result in an overload condition. In such cases, the Rupture disc would isolate the vented media from the relief valve. Resolution indicates the smallest incremental value that you should treat as meaningful. 1) installation in piping or pipeline systems is to optimally protect and minimize the downtime of the system/plant. Contract Manufacturing | Brewery Building. As the rupture disc is a one-time-use device. Personnel near the fill operation should be informed, and suspension of nearby activities during the fill is recommended. Remember too, these events shouldnt happen but we are forced to prepare because they could and do. Although the vent line was procured from a commercial source, it was not of sufficient strength to contain the hydrogen gas pressure relief. Morphologies of the fracture were observed by scanning electron microscope and the relatively chemical compositions were analyzed by energy dispersive spectrometer. They are designed to act in compression. % After all, the opposite scenario cant occur if the safety device is properly calibrated because it would activate otherwise. This graph can prove useful for analyzing short-duration events. Subsequently, corrective action was taken to increase the vent line diameter and to add bracing. Analysis on Bursting of Rupture Disc Made by Inconel 600 Alloy 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. This can create a problem for the typical vessel discharge port that may become partially or completely blocked, thereby resulting in potentially higher than expected rupture-disc burst pressures and restricted discharge flow. Upgrade: Are there other disc materials or newer disc technologies that will allow the maintenance interval to extend beyond current limitations? Frequent inspection of the hydrogen system would likely have prevented some failures, since deteriorated or missing components, especially those exposed to weather conditions, were found in post-incident inspections. J. Failure Behaviour of a Thin Domed Steel Disc with and Please subscribe to my monthly newsletter so you don't miss a thing. For instance, a sensor requires a certain minimum time to get a reading, which limits its speed of response in the case of a typical thermocouple, it may take a number of seconds to respond to changes in temperature. The burst disk was damaged by water entering the vent line, freezing, and expanding against the burst disk. We can sense, monitor and control the systems but we cant protect them very well in that way alone. The HPRD high pressure rupture discs can be used for pressures up to 5000 bar and temperatures up to 400C. care to be exercised during installation not to damage the rupture disc. Engineered to fail. Additionally, the welding joint is another unwanted influencing factor. A plugged outlet line on a continuous-feed autoclave system caused an over-pressurization, which resulted in the burst disk performing its function and discharging the autoclave contents, including hydrogen gas, through the vent pipe. The following items form a good starting point for data collection: Actual normal and maximum operating pressure, Actual normal and maximum operating temperature, Discharge to atmosphere, pressure relief valve or header, Rupture-disc performance history in this location, Photos of rupture disc, holder, installation, Signs of abnormal operation: for example, pin-hole opening, partial opening, slippage and corrosion products. Investigation on the degradation and opening behavior of knife blade burst disks, J. The emergency responders cooled the tube trailer with water and closed the isolation valves to extinguish the fire without further incident. If the sample rate is below the Nyquist frequency, regenerating a true representation of the scenario without distortion is impossible. Various industries use different sampling and reporting strategies to manage this. R. Rivera, A. Chiminelli, C. Gmez, et al, Fatigue failure analysis of a spring for elevator doors, Eng. In some circumstances, a safety device may fail at a value other than intended usually because an environmental condition compromised the device. The vessel discharge port could then become partially or fully blocked, resulting in higher than expected burst pressures and limited discharge flow. The following picture (Fig. Getting the Most Out of Your Rupture Disc - Chemical Engineering Activation of safety devices should happen relatively rarely. If the valve activated, this means, at minimum, that the valve reached its set pressure. When the relieving fluids may impede the proper operation of the pressure relief valve. 1, API RP520, API RP 521, and Crane TP-410. These devices prove most effective when they fail according to pre-established specifications. The Resistance to Flow Method analyzes the flow capacity of the relief piping and accounts for the frictional losses of the relief piping and all components. (Notification req'd), S: Witness, but spot check basis. Failure analysis of a pressure vessel subjected to an internal blast Rupture Disc - an overview | ScienceDirect Topics One key lesson learned is to consider the use of spring-style pressure-relief valves instead of burst disks. Next comes the control system. Subscribe to the SMT Newsletter to Get Industry News & Tips: document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); Copyright 2020 Smart Machine Technologies, Inc. | Privacy Policy, (276) 632-9853 | 650 Frith Drive | Ridgeway, VA 24148. Figure 2. Make no mistake, a sensor will report some value. [1] Functions when the pressure creates an instability in the dome, resulting in reversal, or buckling, of the dome. The rupture disc must be marked at a pressure within the manufacturing range. In time, the tank warmed, became over-pressurized, and ruptured. That said, most systems are designed to handle what should occur. For example, consider a pressure sensor that has a membrane whose deflection is measured to indicate pressure. Amazing and detailed description of the rupture disc and safety installation. Materials can build up and solidify on the internal surfaces of the disc. So they offer standard burst strengths that are high by common standards [~30 W.C. (~1 psi)]. Engineered to Fail: Describing How Rupture Discs Work /Length1 24592 Burst disks prematurely failed below their rated pressure. This Kr accounts for the holder and the bursting characteristics of the disk. The sensors construction and calibration can affect its accuracy. Sampling and resolution. In order to use this method for rupture disc sizing, the following four conditions must be met: This is popularly known as the 8 and 5 rule. Reduced fugitive emissions - no simmering or leakage prior to bursting. 7) Rupture Disc Final Visual Inspection/Documentation Review / Pre-Shipment Inspection may be combined within one time visit. And if your processes, or surrounding environment, have changed in any way since the door Read More. Charact. All rights reserved. resistance. Due to their inherent design, discs are often subject to fatigue and rupturing much more than PSD doors. CTL-Failure Analysis of Corroded Rupture Discs Most rupture discs function in conjunction with a holder that contains key interface features that help control bursting characteristics and effect a leak-tight seal. Anal. This article reviews some of these practices, real-life observed consequences, and corrective or preventative measures that can improve rupture disc performance. Holder inspection: Holder inspection should include examination of the seating surfaces for damage, corrosion, or product buildup. The key lesson learned was that the vent stack design should be re-evaluated. A very thin membrane will be quite responsive to small changes in pressure, deflecting a large amount (typically in a less-than-linear fashion). When rupture disc problems are experienced, it is important to gather as much information as possible to arrive at resolution quickly. By quantifying this performance characteristic, rupture disc devices may be selected. Do you need to monitor the pressure to control the amount of heat applied? Burst disks can provide valuable pressure protection and can be used to meet code requirements. react quickly enough to relieve the excess pressure quickly. Common solutions to this problem include the following: Use of heat tracing or steam jacketing around the vessel nozzle and rupture disc holder, Use of a viscous tee style holder (Figure 1), which continually wipes the disc surface, preventing product buildup, Use of a flush-mount-style rupture-disc assembly, which eliminates any dead space in the vessel nozzle that could accumulate solidified materials. A failure analysis was requested to determine if the discoloration was due to corrosion and if so, the cause. Im concerned that one or more of the batteries may actually explode. The real value in these devices stems from taking a failure that might cost human lives and millions of dollars and turning it into a manageable event. Overall an interesting article as per me. A quick way to check for holder damage due to over-torque is to put a straight edge along the gasket face and look for signs of significant bending (Figure 5). After the first burst disk failure occurred, the vent line was not sufficiently attached to take the thrust force from the hydrogen release and bent outward violently, damaging some adjacent vent system components. It is recommended that a hazard analysis be performed to assure that all effluent vent operations are discharged to a safe location that is remote from people and property, since discharge fires are common. It was burst after only 2000 times of operational circles. It took off like a rocket into the air, landing on a nearby van and crushing it completely. When the pressure rise is so large and rapid that extremely fast-acting is required to prevent catastrophic failure. In this case the disc is subjected to transverse load. Rupture discs are, by their very nature, ever more fragile if theyre made for low burst pressures. high reliability to prevent unnecessary downtime of the system. The present situation and the existing problem of the rupture disc for cryogenic liquid tank were introduced by the analysis of the failure of rupture disc for cryogenic liquid tank, and relevant . At Continental Disc Corporation, we specialize in engineering and manufacturing the highest caliber rupture discs on the market. However, the device doing the sampling, such as an analog/digital converter, also imposes constraints, both mechanically and due to downstream devices such as controllers or recorders and their associated needs. This matches our reality, as makers of such devices are governed by a number of code requirements designed to ensure the accurate manufacture of their products. Selected component failure rate values from fusion safety assessment Troubleshooting Field Failures of Rupture Disks Many process materials are prone to building up and solidifying on internal surfaces. A difference of a few percentage points indicates a controls problem. The rupture disc manufacturer publishes the actual Net Flow Area (NFA) for each model and size. Those pressure ripples work in unison to fatigue all of the structures associated with the blower, including the housing, ducts, mounting legs, and the rupture disc itself. The FEP PDF Marston Bursting Discs - Emerson Finite Element Analysis of Rupture Disc - YUMPU 59(2008) 1088-1095. What about a large hole 1 inch? Usually we should but in some instances the data can mislead us. The hydrogen ignited at the vent tube exit. The device may be re-installed if desired as long as the disc hasnt been removed from the holder. In addition, you must consider the way in which the data are compiled, graphed and analyzed. Sampling involves two pieces, the rate and the resolution. This paper attempts to numerically simulate the deformation and failure behaviour of forward domed rupture disc, with rectangular scores at a high impulse loading rate of 500 MPa/s, adopting a visco-plastic, and . The goal of the flange connection is to apply the proper amount of clamping load for the rupture disc and holder to function correctly. or having the dome away from the process (. The PTFE film Greater sensitivity to mechanical damage. The performance of bursting at the predetermined pressure is. Inadequatefuel gaspressureduringstartup Inadequatepressureduringlead Buffer Gas Compressor discharge gas Some of the most serious incidents within the hydrogen industry have been associated with pressure-relief devices. Scientific.Net is a registered brand of Trans Tech Publications Ltd ERIC GOODYEAR is a senior engineer at Oseco, Broken Arrow, Okla. Email him at egoodyear@oseco.com. We can safeguard them, though, and hopefully learn from any events to protect ourselves even better in the future. |. If sampling occurs at 2 the Nyquist frequency, its possible to accurately reconstruct the input signal. Rupture disc life is generally tied to the stress history (pressure and temperature) applied to the disc. For further information on how we how we use cookies and how to change your browser settings, please read our, New Product Improves Process Performance, Reliability, and Safety, Continental Disc Corporation Appoints Mike Waters as New CEO, Introducing: TSL Engineered Products, Global Manufacturer of Specialized Solutions. The CO2 system failure created a projectile that physically damaged a nearby hydrogen storage unit, causing a fire. A factor Kr that represents the velocity head loss due to the rupture disc device is determined experimentally in flow laboratories by the manufacturer for their line of products and is certified per ASME Section VIII, Division 13. [8] Consider the ramifications of a personal computer maker revealing that their computers were designed to crash. Site Copyright This is simply another clue in the mystery of any system event. A burst disk associated with a tube on a hydrogen tube trailer failed below design pressure during a fill operation and vented hydrogen through a vent tube. Gaskets: Flange gaskets have an effect on the applied load as well. I am a Mechanical Engineer turned into a Piping Engineer. Two burst disks associated with two tubes on a hydrogen tube trailer failed prematurely while being filled, releasing hydrogen to the associated vent line. Increasing the sampling rate could rectify portions of this problem. The resulting pressure in the ammo can may cause it to explode violently. This information may be located on the rupture disc tag or in the installation instructions provided. Fail. If the relief fluids are vented in the common header vented media can result in either corrosion or polymerization. API RP521 recommends using a Kr of 1.5. This potentially can cause a catastrophic failure because the system may not register or report the rise to give enough time to react. An important lesson learned is that burst disks should be properly installed. The hydrogen gas and the autoclave system were turned off immediately, but fire continued to burn in the autoclave cell. Inst 33 (2011) 2351-2358. Anal. Once the disc has been removed from the holder it is recommended that the disc be replaced. He has technical responsibility for a variety of products including rupture discs, explosion vents, and mechanical explosion and fire-protection products. stream 6 Advantages of Pasteurization of Foods and Semi-Solids, What to Consider When Replacing an Explosion Door. Traditionally rupture discs for high pressure applications are manufactured by a weld seam which has an influence on the burst pressure. Relatively low pressures and static conditions will generally result in very long disc life, while cyclic conditions approaching the burst pressure will result in shorter disc life. Rupture disc devices require periodic maintenance just like any other piece of equipment. The shell's volume is 7.5 m 3. Rupture discs cause all sorts of problems- detection, frequent replacement, cost, drips from the excess flow check, etc. Steam Box Vs. These failures may have been prevented with closer attention to the design and maintenance of the burst disks and their integration into the hydrogen storage and piping systems. It is a one-time-use device that is either destroyed or permanently deformed in response to over pressurization and then must be replaced. economical. I think a rupture disc might be a decent solution but again commercial ones are cost prohibitive. The vent pipe exhausted the hydrogen gas mixture into the autoclave cell, where it ignited in a fireball and then ignited nearby combustibles. Rupture Discs are frequently used for over-pressure protection in chemical, petrochemical, oil & gas, and sanitary applications. In the end, the output of most sensors is a signal already laden with caveats as to what its amplitude really reveals. Polymers have characteristics of virgin resins, which are critical for meeting food-industry safety standards. Our networks are powerful but bad things still happen to good systems. Dynamic modeling of heat exchanger tube rupture | BMC Chemical The shorter the spike duration and the lower the sample rate are, the more dramatic the effect. Loss Prevent Proc. In such a configuration, the design considers a double jeopardy scenario and gives protection with both the vessel overpressure and the pressure relief valve failure. As stated earlier, rupture discs and pressure relief valves can be used in parallel. Since a burst disk is activated by differential pressure, back pressure against the burst disk discharge will cause it to burst at a higher pressure than intended. mark on the PTFE film was fragile leading to the mechanical failure of the film KS B ISO 6718-2013,Bursting discs and bursting disc devices. 5)100%Rupture Disc inspection which is covered by the combination of witness / spot check / record review inspection & tests listed above and vendor's originalQC activity shall be confirmed by Purchaser's inspector prior to shipment. A burst disk is sometimes used as a backup to a resettable pressure-relief device such as a relief valve.
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