Editorial

Explosion isolation is essential for comprehensive explosion protection. Without isolation, an explosion safety concept is not only incomplete, but is also a waste of money for operators as:

In almost every production facility, individual plant components are interconnected by means of pipelines. The purpose of explosion isolation is to seal these pipelines in the event of an explosion to prevent the propagation of pressure and flames, thereby protecting the adjacent plant components. Precompression and flame jet ignition increase the severity of the explosion in the connected vessels. This leads to secondary explosions that can cause even more catastrophic damage.

Isolation systems prevent an explosion from propagating, thereby reducing the effects of the explosion to a minimum. Adjacent system components are optimally protected.

A distinction is made between active and passive isolation systems:

Active systems use sensors or detectors to detect an explosion as it occurs by registering the rising pressure or flames as they form and activate the associated isolation device, e.g. a quench valve.

Due to their structural design, passive isolation systems react purely mechanically to a propagation or loss of pressure. The latter also applies to explosion isolation flap valve. They are kept open during normal mode by means of the currents present in the pipeline. In the event of an explosion, the valve closes due to the propagating pressure front, effectively preventing the further propagation of pressure and flames.

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As the inventor of flameless explosion venting, REMBE is once again challenging the status quo with the new Q-Box R3leaf, the world's first sustainable device for flameless explosion venting.

After years of systematic development, testing and successful approval tests, REMBE is convinced that it has contributed to more than just an improvement in flameless explosion venting technology. Instead, the aim is to set a good example and send a clear signal that everyone can reduce the carbon footprint in our industry. 

Fig. 1: The Q-Box R3leaf as the first sustainable flameless explosion venting device

During development of the Q-Box R3leaf the focus was on sustainability and the central question: Where can the status quo be further challenged?  

The development of the Q-Box R3leaf expands REMBE's line of flameless explosion venting devices with a product optimised in terms of both effectiveness and sustainability.  

Thanks to the selection of materials, the geometry of components and appropriate joining processes, it was possible to significantly increase the packaging density, avoid the need for emission-intensive joining and coating processes, and at the same time significantly improve the effectiveness of internal and international logistics processes. These optimisations affect the entire supply chain of the Q-Box R3leaf and thus ensure reduced CO₂ emissions.

Thanks to continuous development, it was possible to significantly increase the venting efficiency of the Q-Box R3leaf, allowing plant operators to reduce the number of flameless explosion venting devices required on their plant.

How does an explosion occur?

The topic of “explosion protection” is omnipresent for plant operators and machine manufacturers when it comes to handling or transporting flammable and explosive dusts. Contrary to the widespread assumption, the risk of explosion extends beyond gases, as flammable dusts can release enormous forces.

The following conditions, also known as fire triangle or dust explosion pentagon, must exist for an explosion to occur within a production facility or machine:

Fig. 2: Dust explosion pentagon

If any of the aforementioned conditions are eliminated, explosion protection has essentially been practised. However, if this is not possible at all times and in all operating states, explosion hazards persist. This necessitates categorizing explosion-prone areas into zones and systematically installing protective measures accordingly.

What is flameless explosion venting? 

Flameless explosion venting devices are primarily used to protect vessels or plants against the main effects of explosions, flames and pressure, which would be released unhindered into the environment if conventional explosion venting was used. To put it simply, they consist of two elements: the explosion venting device, such as an explosion vent and a downstream flame extinguishing element. This decreases the explosive pressure to a level that is harmless for the protected plant, and at the same time reduces the temperature of the combustion gases to a harmless level.

Flameless explosion venting devices are used wherever safe pressure relief in the event of an explosion is not permitted due to the potential proximity to people, other plants or objects.

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Meeting safety and process requirements at the same time is sometimes a challenge, especially in the pharmaceutical industry. Dust-handling equipment has to be equipped with explosion protective systems, which must also comply with all hygiene and sanitary requirements in production. The solution: Vent panels that can be used to produce hygienically sensitive powders.

The EGV HYP vent panel is an economical solution to the problem described, according to the strict criteria of the EHEDG (European Hygienic Engineering & Design Group). Specially designed for hygienically demanding processes, it protects the vessel in the event of an explosion by releasing flame and pressure. The smooth surface with the patented, full-flat, chamfered gasket system prevents deposits during the production process and during the cleaning of the system and thereby cross-contamination between batch processes. With the new, contrasting blue color of the seal, it is also easy to see if the seal is damaged and/or a mounting failure has happened.

The EGV HYP can be used without hesitation in critical systems such as spray dryers with / without CIP cleaning, fluid bed dryers and mixers and therefore offers a cost-effective safety solution according to the requirements of hygienic design.

Fig.1: Certified in accordance with EHEDG: EGV HYP with patented, bevelled sealing concept for absolute hygiene. 

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Throughout the chemical sector, processes operating at high temperatures and with highly corrosive process media are common. Traditional signalling devices were not always compatible with such conditions and therefore are often over-looked as an additional accessory to monitor the status of the rupture disc.

Developments in technology mean even companies in this sector can now use rupture disc signalling systems, helping not only improve productivity and safety but also supporting with environmental concerns. German manufacturer, REMBE, is the European leader in the manufacturing of pressure relief devices and explosion safety systems and their product range encompasses some of the most robust rupture discs and signalling solutions available to add significant operational value within the chemical industry. Here REMBE discuss how its intelligent signalling solutions will keep you informed about the status of your entire plant while not being affected by the harsh operating conditions.

For processes operating with potentially harmful media the ability to shut down the process quickly and safely mean the risk of leakage is eradicated. Complying with explosive atmospheres and intrinsic safety industry standards, the signalling devices are designed to provide rapid notification of rupture disc activation, helping ensure safe management of the process while minimising downtime. REMBE’s signalling devices can easily be integrated with customers control systems to provide visual or acoustic notification of disc burst or to shut down the plant where required.

With non-invasive signalling devices, which make it impossible for the process medium to escape, processes with critical pressures and demanding media can also be reliably monitored. The following text explains the non-invasive monitoring unit NIMU in more detail.

Stop unnecessary downtime

For customers for whom compatibility with harsh operating conditions is of paramount concern the NIMU (Non-invasive monitoring unit) is a reusable rupture disc signalling system designed for rapid notification of rupture disc activation even in the harshest chemical environments. The REMBE NIMU sensor is not in contact with the process meaning it is not affected by challenging process conditions or corrosive media.

The intrinsically safe NIMU is installed into a tapping within the outlet of the rupture disc holder, completely isolated from the process so it does not create any leak paths and is not damaged following disc activation - critical for chemical customers where leak paths cannot be tolerated.

With the traditional membrane type signalling devices, false alarms were unfortunately common place, as the harsh operating conditions could cause the device to activate even if the disc itself had not opened. This false signalling would cause unnecessary and costly process downtime. Unlike these traditional devices, the NIMU is not negatively affected by the process.

 Fig. 1: Signalling device NIMU (Non-Invasive Monitoring Unit)

Additionally, membrane detection systems are single use, meaning additional replacement costs. With the NIMU this additional cost is eradicated – the NIMU enhances overall dependability of rupture disc installations while reducing long-term expenditure. Not only is the signalling device fully reusable following disc functioning it is also reusable after routine maintenance checks. Easy to inspect during such maintenance routines, its closed circuit design allows it to be refitted into the holder by the same operator inspecting the disc, simplifying and quickening the maintenance process, a must to meet the demanding productivity requirements within the chemical processing sector.

When used in combination with the REMBE IQ Safety Cockpit the operator can be instructed in the event of a system disruption and can implement the relevant emergency management protocols. The affected employees can be individually informed of a process shutdown and co-ordinated response to identify the cause and get the plant back up and running as quickly as possible.

Reliable Monitoring of Rupture Discs protecting FPSO processes

Rupture discs installed on a gas compressor module are designed to protect the tubes on a heat exchanger from rupturing due to overpressure. Rupture discs are selected due to their response time in milliseconds. As output is directly correlated to the production from the compressor module it is critical that a rupture disc with good life cycling capability is installed, otherwise as the operating pressures increase the rupture disc will be pushed to its operating limits and fatigue causing frequent failure and unnecessary loss of production through downtime. The vent lines of several heat exchangers and other equipment are typically connected the flare system with a common manifold to save space on deck. This leads to the fact that there is variable back pressure on the Rupture disc protecting a heat exchanger. This situation requires a double disc assembly. The first Rupture disc is designed is to protect the heat exchanger shell against excessive overpressure in case of tube rupture. The second disc is typically a forward acting disc designed to resist the back pressure and set at differential pressure the required relieving pressure of the first disc less the amount of maximum back pressure.

Conventional signallling devices which are invasive are not suitable for such a harsh environment since they would be wetted by the medium on the downstream of the second rupture disc. For customers for whom compatibility with harsh operating conditions is of paramount concern the NIMU (Non-invasive monitoring unit) is a reusable rupture disc signalling system designed for rapid notification of rupture disc activation even in the harshest chemical and corrosive environments. The REMBE NIMU sensor is not in contact with the process meaning it is not affected by challenging process conditions or corrosive media.

Engineers designed a version of NIMU for such double disc assemblies and a special design for forward acting rupture discs to provide a reliable and long life signalling device for such demanding applications of the Offshore industry. This way in addition to the first disc, the second disc’s condition could be continuously monitored improving the safety and reliability of the processes on FPSOs.

Fig. 2: Double Disc Assembly

Fig.3: Double Disc Assembly with signalling device NIMU

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Avoid unnecessary downtimes with intelligent signalling systems

Rupture discs and safety valves have become indispensable for manufacturing companies in the chemical industry. However, there is a need to catch up in terms of signalling.

The opportunities offered to operators here are both diverse and economically interesting. With non-invasive signalling that can be integrated into the rupture disc, even processes with critical pressures and demanding media can be reliably monitored.

Processes involving high temperatures and highly corrosive media are widespread throughout the chemical industry. In the past, conventional signalling was not always compatible with such extreme conditions, which is why it is now often overlooked as an additional process monitoring system.

The use of modern signalling equipment not only helps to improve productivity and safety but is also helpful in terms of addressing environmental concerns. The German manufacturer REMBE is a European leader in the production of pressure relief devices, explosion protection systems and the associated signalling devices. The company's product range includes some of the most robust rupture discs and signalling systems available on the market. These solutions create significant operational added value in the chemical industry by reliably monitoring safety systems and critical pressure relief devices.

In processes involving potentially harmful media, the risk of leakage can be reduced via a quick and safe shutdown. REMBE's well-designed signalling systems comply with both industry-relevant standards for explosive atmospheres and the intrinsic safety standards. By providing rapid notification of a burst rupture disc, they help to safely control the process while minimising downtime. High-quality signal transmitters can be easily integrated into the existing control systems in order to transmit a visual or acoustic signal when the rupture disc bursts and to shut down the system if necessary.

Avoiding unnecessary downtime through non-invasive signalling

The NIMU (non-invasive rupture disc monitoring) signal transmitter is suitable for systems exposed to harsh operating conditions. This reusable monitoring system is explicitly designed to provide rapid notification of a burst rupture disc. The REMBE NIMU sensor does not come into contact with the process itself, so it is not affected by harsh process conditions or corrosive media and ensures maximum tightness even for systems containing extremely corrosive chemicals.

The NIMU is mounted in a blind tap in the outlet on the rupture disc holder. Thus, the signal transmitter is completely isolated from the process. Potential leakage after the rupture disc has burst is also prevented – this is essential for customers in the chemical industry where leaks cannot be tolerated.

Fig. 1: Signalling NIMU (non-invasive rupture disc monitoring)

The signal transmitter is fully reusable not only after the rupture disc has burst, but also after scheduled maintenance work. During such maintenance work, the closed circuit of the rupture signalling system makes it easy to perform a function test – the rupture disc can then be reinserted into its holder. Furthermore, the operator can do this without external assistance, which simplifies and speeds up the maintenance process. This is simply a must in the chemical industry due to the demanding productivity requirements.

Reduce environmental risks

Environmental concerns such as emissions control have become increasingly important for chemical manufacturers. The ability to quickly detect a leak within the process without external support brings significant benefits.

On the one hand, the SBK signal transmitter ensures fast and reliable fault signalling via the bursting of rupture discs and, on the other hand, has the unique ability to monitor leaks from upstream rupture discs. REMBE has specially developed this signal transmitter for processes with high temperatures where alternative signalling systems may no longer be suitable. The combination of leak detection and signalling in one product is a cost-effective solution. The materials used remain stable even at extreme temperatures and ensure high reliability in the long term without the risk of premature failure.

If the SBK signal transmitter is integrated into the process control system, it provides continuous monitoring of the rupture disc and reliable fault indication when the rupture disc bursts. Even marginal leaks within the process are detected. The application of the SBK monitoring system in the chemical industry, where the loss of process media is costly or harmful to health, significantly increases plant efficiency. At the same time, it ensures compliance with safety and environmental standards.

Integrated signalling – reduce installation points, ensure reliable monitoring

Whereas with other signalling systems the rupture disc and signalling devices must be installed and maintained separately, the SGK versions allow the signalling to be integrated directly into the rupture disc. Thanks to their unique design, it is not necessary to run a cable out of the rupture disc holder, thereby eliminating the need to drill a hole for the signal cable. Especially for processes with a low set pressure, where (for example) the non-invasive NIMU signalling may not be suitable, the SGK signalling systems allow continuous monitoring. The SGK versions are available with the KUB and IKB reverse acting rupture discs and the ODV triple-section rupture disc.

Now CSA Certified for North America / Canada

Classes, Divisions and Zones

Atexxo Manufacturing has released the Apple iPad mini 6 which is global certified and suitable for use in Zone 1 and Zone 21 hazardous locations. The explosion proof iPads are originally manufactured by Apple then converted and certified according to the ATEX directives and IECEx standards by Atexxo Manufacturing. This makes the ATEX/IECEx Tablets suited for safe use in gas/vapour Zone 1 and dust Zone 21 hazardous areas. Sim-card can be installed by the end-user themselves. The devices are suited for Apple’s DEP (open) Business Manager Program.

All features of the original product are preserved, except for the fingerprint scanner.

The ATEX/IECEx iPad mini of the 6^th generation comes with an aluminum case finish. The ATEX/IECEx iPads are suitable for use in extreme demanding environments. They are available in both 64gb and 256gb versions.

Beside safe use as a tablet computer, all versions are excellent for use as an explosion proof camera or RFID scanner. For Middle East countries, versions with blocked cameras are available.

Explosion safety level:

II 2G; II 2D; II 3D,  Ex db IIC T4 Gb, Ex tb IIIA T135°C Db, Ex tc IIIB T135°C Dc

Class I, Zone 1 AEx db IIC T4 Gb Class I Div 2, Group A, B, C, D T4

Features:

- 64Gb or 256 Gb + Cellular- Self Sim-Card Installation - Original Apple IOS software- Suited for Apple DEP (open) Business Manager Program- Global certified (ATEX, IECEx, UKCA, CSA, INMETRO)

Typical Applications:

- Connected fieldworker- Digital twins- - Industry 4.0- Oil and Gas extraction sites- Petro Chemical plants- Offshore platforms

For more information please contact our sales department

www.atexxo.com
This email address is being protected from spambots. You need JavaScript enabled to view it.
+31(0)186601299

Once again, REMBE GmbH Safety+Control is challenging the status quo of autonomous protective systems. Thus, the globally increasing environmental influences and weather extremes prompted REMBE engineers to test the protective effect of REMBE explosion vents also against weather-related water and air permeability.

Particularly in plants and processes with high demands on water and air tightness, explosion vents that are directly exposed to weather conditions due to their installation position often represent a potential point of entry and thus a hazard for the bulk materials themselves. REMBE therefore applies what is legally required for construction elements such as windows and doors to the various explosion vents in the explosion protection area. Within the framework of large-scale weather simulations, the REMBE explosion vent types ODV, EDP, EGV-HYP, as well as the new vent duct cover KAD-LIC have been tested for their properties of air permeability, watertightness and their resistance to wind load. BS EN 14351-1, the product standard for windows and doors, served as the basis and classification.

The results of the weathering test are extremely impressive. A comparison of the test results with real weather conditions shows that storms with wind forces of up to 14 on the so-called Beaufort scale (bft) - this corresponds to wind speeds of up to 166 km/h - have no influence on the protective effect of the explosion vents. Even in heavy rain in conjunction with wind speeds approaching 120 km/h, the explosion vents exhibit a high degree of tightness. A comparison with the windows used in the construction industry illustrates the high weather resistance: The REMBE explosion vents achieved the same and in some cases significantly better test results than the currently available windows for residential buildings.

What is the added value of weathering testing?

The REMBE explosion vents thus not only protect the plant in the event of an explosion through targeted explosion venting, but also ensure effective protection of the bulk materials themselves from external environmental influences during normal operation. The risk of contamination by water, dust and air as well as collateral damage due to swelling or excess weight is thus minimised.

Fig. 1: Examples of the tested explosion vents (left: Explosion vent EDP; right: Explosion vent EGV HYP)

• Certified weather resistance
• Effective protection of the plant and its products from environmental influences
• Air leakage of < 0.75 m³/h m joint length
• Impervious to driving rain up to a wind force of 12 bft (120 km/h) and a precipitation rate of 440 mm/h
• Wind stability up to a wind force of 14 bft (166 km/h)

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This article can also be found in the issue below

In the context of the desired decarbonisation, hydrogen is becoming increasingly important as an energy carrier (thermal utilisation) and as a starting material for chemical production lines (molecular utilisation). Plant operators and manufacturers of specific subcomponents often plan to use methane-hydrogen mixtures initially, and then to continuously increase their hydrogen content. The long-term goal is to completely substitute methane with hydrogen. However, it is often disregarded that the safety concepts and technologies suitable for the original methane operation are only functional to a limited extent or not at all for protecting plants, single components and infrastructure during operation with high hydrogen concentrations.

Particularly in the area of explosion protection, as well as pressure venting at medium to very high overpressures, the existing concepts must be carefully reviewed using the available models, and possibly re-evaluated. A comparison of the explosion characteristics of stoichiometric methane-air and hydrogen-air mixtures quickly makes this necessity clear.

Fig. 1:Comparison of explosion characteristics under atmospheric conditions (20°C; 1.01 bar) 

Sources: BAM final report on research project 2539 and own investigations.

If the maximum explosion pressure at atmospheric conditions is about 8 bar in each case, significant increases can be observed both in the KG value (rate of pressure rise) and in the laminar flame propagation speed. This may mean that safety devices tested with methane explosions show too high inertia for the rapid pressure increase. Valve-type protective systems can be severely damaged when they respond that they do not return cleanly to their original state and their functionality is impaired or they are operated unsafely. Special care must be taken when designing and assessing the geometric dimensions and sizing. For example, certain length-to-diameter ratios of vessels and pipes, especially for hydrogen as a Class IIC gas, favour the tendency towards detonative transition. If explosions propagate from one vessel to another via a pipe, there is also the risk that the ignitable mixture is pre-compressed in the second vessel, which results in significantly higher explosion pressures compared to explosions under atmospheric conditions. A hydrogen-air mixture is also more susceptible to ignition than a methane-air mixture due to the lower ignition energies and ignition temperature. In addition to the expected more severe course of events, the probability of occurrence is also higher.

Hydrogen explosions under prepressure

In addition to the aforementioned secondaryprepressurisation in the event of an incident, there are applications in which ignitable mixtures are deliberately precompressed and can ignite uncontrollably under certain circumstances. For several reasons, these scenarios pose a special challenge with regard to the design of the corresponding equipment and to the constructive protection concepts.

Firstly, the existing normative regulations do not provide any models for the design of safety relief devices for gas explosions under prepressure. Due to the prepressure at high dynamics, the problem at hand is neither covered by DIN EN 14994 (Gas explosion venting protective systems) nor by DIN EN ISO 4126 (Safety devices for protection against excessive pressure). Thus, there are no assured design standards, which means that the problem is in the "grey area of safety technology". Secondly, the explosion dynamics are significantly influenced by barely assessable turbulence-generating effects, which primarily result from the geometry at hand. Thus, it is difficult to predict what explosion pressures, flame propagation speeds and rates of pressure rise are to be expected. Whether a detonative transition occurs and whether an explosion venting device is suitable to protect the present scenario therefore requires separate investigations.

One possible way to validate a safety concept for the "hydrogen explosion under prepressure" problem dealt with here – in addition to very complex numerical simulations – is experimental verification. For this purpose, the protection scenario is simulated as realistically as possible with flameproof components and the explosion pressure resistant concept is tested with regard to its functionality via repeated explosion tests. Starting from a stoichiometric methane-air reference test, either the proportion of hydrogen in the methane-hydrogen-air mixture, the prepressure or the combustion air ratio is increased when testing a pure hydrogen-air mixture, depending on the problem. By registering the pressure curves within the simulated structure, the maximum explosion pressure can be inferred and the tendency towards detonative transition can be estimated. The aim of the verification is always the identification of safe operating parameters as well as to check product suitability, as no standard product certification is available due to the lack of a normative basis. When selecting a suitable product/explosion venting device, it is important to ensure that it is not only suitable for explosion venting, but also guarantees a long and reliable service life under the prevailing conditions during normal operations. If the explosion venting device was an explosion vent or rupture disc, the burst pressure, operating ratio, working temperature as well as the occurrence of vibrations and cyclic loads and, of course, the corresponding material must be taken into account when making the selection.

REMBE GmbH Safety+Control has been a leader in the technological fields of Process Safety and Explosion Safety for almost 50 years. As such, the careful selection of suitable safety systems and (explosion) relief devices is a key aspect of the company's service portfolio. REMBE has thus built up a profound understanding of how to analyse customers' processes and plants and identify suitable protection technologies. In collaboration with REMBE Research+Technology Center GmbH, an independent testing laboratory accredited to EN ISO / IEC 17025:2018, REMBE can also validate even highly complex protection concepts on an experimental basis. Especially in scenarios where new technologies need to be tested, no assured design standards are available or high-precision protection concepts are required, it is precisely this multidisciplinary approach that enables REMBE to develop high-quality solution concepts. In collaboration with the customer, the company combines experimental verification with its extensive expertise in explosion safety and explosion venting solutions to create highly specific protection concepts tailored to the customer's processes.

 Fig. 2: REMBE produces high-quality explosion vents and rupture discs that are not only aesthetically appealing, but also suitable for safely venting hydrogen explosions under prepressure.