Remote I/O systems offer many benefits when it comes to automating LNG plants, LNG carriers and LNG-powered ships. They save space and weight, and open up greater operating possibilities. State-of the-art developments such as Ethernet-APL are paving the way to the digital age.
The global demand for LNG is skyrocketing. We need a way of bridging a supply gap of around 390 million tonnes a year by 2040. In response to this, a great many new natural gas liquefaction plants will be popping up over the coming years. Across the world, we will also witness the expansion of the value creation chains that follow this stage, from loading equipment and tankers to unloading terminals and regasification facilities. As things stand, around 80% of LNG tankers are equipped with R. STAHL's products. One of these products is R. STAHL's remote I/O systems.


Rigorous explosion protection standards

Even though the number of LNG accidents has remained low in the past, incidents such as the Freeport blast in Texas, USA, and the Hammerfest fire in Norway highlight how crucial it is to have fully functioning safety equipment in LNG plants; it is also vital to do whatever is needed to minimise the risk of human error. When they are constructed, equipped and operated properly, the risks associated with LNG plants are as manageable as they are with any processing plant.
LNG, which consists predominantly of methane, is categorised as explosion group IIA and temperature class T1. Though it is less explosive than hydrogen(IIC), it is nonetheless important to take into account the explosion limits(LEL 4.4 vol%, UEL 17.0 vol%) and other characteristic values with an influence on safety. LNG plants must be powered using explosion-protected products, which are readily available. Suitable devices are also available for the purpose of process instrumentation and local operation. Ex-certified equipment can also be employed for lighting, monitoring and security purposes. R. STAHL has suitable, LNG-safe products for all such applications. Embracing automation and digital modernisation will be key for those who are seeking to make their installations future-ready – if you want to produce and transport LNG efficiently to keep your prices competitive, you will need maximum-efficiency plant automation.

Remote I/O technology as the basis for digital concepts

Over the past few years, the digital modernisation sector has made significant progress. Remote I/O technology is now used for digital data transmission and has opened up a whole host of diagnostic possibilities. Additionally, it enables the latest automation concepts, such as NOA (NAMUR Open Architecture), to be realised. And with the development of Ethernet-APL, which will extend the reach of Ethernet in industrial environments to hazardous areas, LNG plants will be able to further capitalise on this technology.
Modern remote I/O systems additionally support structures of the kind developed by OPAF(Open Process Automation Forum) so that plants can be furnished with small-scale, localised intelligence. A few remote I/O systems are now able to work with modular plants that are configured using the MTP(Module Type Package) approach. These innovative concepts can even be implemented in equipment that is already in use, further boosting a plant's efficiency.
R. STAHL's Zone 1 remote I/O systems are designed to be used the world over. They possess the necessary certification for explosive gas and dust atmospheres – ATEX and IECEx, as well as FM for the USA and Canada, EAC for Russia, INMETRO for Brazil, PESO for India, KTL for Korea, etc. They also have approval from many bodies(DNV, LR, BV, ABS, CCS, KRS, ClassNK, PRS, RINA, RS, etc.) for the construction of both LNG tankers and ships powered by LNG using a fuel gas supply system.

Less weight, more digital intelligence aboard LNG-powered ships(including cruise ships)

Having fewer cabinets and less wiring translates to significant weight savings. In a real project with around 1000 signals, the remote I/O installation allowed for a weight saving of over 80% – from 23-28 tonnes to just 3.8 tonnes – while still being able to implement redundancy and reserve concepts.
The weight savings and compact construction are also proving useful in fuel gas supply systems(FGSS) that power LNG tankers, and increasingly, other ships such as cruise ships. Ships often only have a few technical specialists on board. In conjunction with modern operating systems, remote I/O technology simplifies operation and trouble-shooting. It even allows remote access by external specialists.

Implement NOA, OPA and UniversalAutomation.org concepts with ease

The NOA concept mentioned earlier, which allows for a second channel for monitoring and optimisation domains, makes it easy to access additional diagnostic data without detrimentally affecting the main process. The UniversalAutomation.org concept is also relatively new. It works with the open ecoRT runtime (based on IEC 61499), opening up the otherwise closed control system world for I/O systems and package units that are able to communicate with the control system via open runtimes. If you delve into IEC 61499, you will quickly realise that the interoperability that renders the coupling and adaptation work unnecessary affords many benefits. R. STAHL is a founding member of UniversalAutomation.org and assists with promoting the technology.
OPA Forum members such as ExxonMobil have driven the development of other innovative automation structures. These automation structures enable small, intelligent I/O systems to communicate – these systems can be implemented using R. STAHL's remote I/O hardware in conjunction with control tools based on IEC 61499 and IEC 61131(e.g. CoDeSys).

Summary: Universal automation and digital modernisation for LNG plants

Incorporating Ethernet-APL technology into LNG plants while they are still at the planning stage can really pay dividends. This enables universal solutions that are no more complicated than conventional installations. On the contrary, the digital products and systems make things significantly easier. Products will be available from mid-2023, including an Ethernet-APL field switch from R. STAHL. By combining these with the modern automation structures that can be implemented using remote I/O technology, it is now possible to design LNG plants that promise exceptional efficiency in the long term and are a safe bet for the future.

■ Contact: R. STAHL www.r-stahl.com