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
