LNG, once a niche market, is nowadays increasingly used as a cleaner fuel for trucks and ships instead of oil or diesel. Power plants have switched from coal to natural gas. As a result, the number of LNG terminals, filling and bunkering stations is also growing and the transport of LNG by water and road is increasing sharply.
The increased demand for LNG has led to an increase in production, transport and storage. Now that LNG is widely available and now more in the public domain, responders to incidents involving a release of this gas must be fully prepared. A common assumption is that LNG is lighter than air. Methane gas, which is the predominant gas in LNG, is lighter than air. However, methane gas loses its buoyancy at temperatures below -105°C. This gives a whole new perspective on a release of LNG and how far the gas cloud will travel before it warms and starts to rise out of harm’s way. On an initial release of LNG the cold liquid is warmed up by the ground it falls onto, boiling off the liquid rapidly. This can be quite alarming. However, once the ground has been cooled then the boil-off rate recedes to a slower steady state. Furthermore not all personal protective equipment is adequate when in contact with cryogenic substances. Some materials, as is with some metals, become brittle and lose their integrity.
These are just a few anomalies associated with cryogenic gases and in particular LNG. Other questions the responding organisations should be preparing for are as follows:
- Which gas detection is suitable and reacts quickest with these super-cold gases?
- How can you control an LNG gas cloud that is released (boil-off)?
- What is the boil-off rate of an LNG pool on water?
- What are the best tactics and control methods should an LNG gas cloud ignite?
- What about using water and foam on LNG pools?
- Can an explosion (BLEVE) occur?
These questions can be answered with an accredited LNG training programme, where the above subjects are handled both theoretically and practically with real live LNG gas simulations where the delegates can actively take part to experience the gas’s characteristics.
The first LNG training facility in northern Europe was built at the former Falck Rotterdam training centre in 2014. After the relocation of the training centre in 2018 and the rebranding to RelyOn Nutec, there were opportunities to realize a renewed LNG training facility.
LNG training facility
The new facility consists of a 10m³ LNG storage tank, which feeds the various training simulators. The installation has a number of safety provisions that meet the latest safety requirements. During the exercises boil-off gas (BOG) is released that creates relatively large clouds of flammable gas. The LNG fire ground alone already covers 400m2 and has a round fire pit of 3.8m2 in the middle. Water screens have been set up at the edges of the training ground to reduce the concentration of combustible gas when the LNG fire pit is being filled. This is also one of the vapour cloud mitigation techniques that can be employed during an emergency. The training facility is located at a considerable distance from the LNG storage and other installations and buildings. Furthermore, it is equipped with three hydrants connected to the RelyOn Nutec’s central extinguishing water system with its own water purification installation.
In the re-engineering of the LNG installation, RelyOn Nutec took into account the wishes of customers and a focus on practical objectives for the emergency response teams and people who work with LNG in their installation, such as those on board of LNG-driven ships. At the first LNG facility developed in 2014, it was only possible to simulate an LNG pool evaporation. With the new facility it is also possible to connect an LNG hose with fittings to simulate an LNG flange leak with a possible 2-phase Jet Fire and the operation and release of a Pressure Relief Valve (PRV) and Thermal Expansion Relief Valve (TRV) but also sealing a flange leak is possible. The options for filling an LNG fuel tank for a truck and flaring off an LNG fuel tank will become possible at the new facility as well.
LNG awareness training and CryoLab
Training with LNG at RelyOn Nutec largely consists of visualizing and experiencing theoretical knowledge about the behaviour of LNG. This usually starts with a workshop in the CryoLab where the cryogenic hazards and properties are explained and demonstrated with liquid nitrogen. After going through and following the safety protocols, the real work follows. The ice-cold metal LNG pipes, the condensation of the BOG from a 50mm pipe with a huge white cloud, an evaporating LNG pool, the whistling of a flute leak, the radiant heat from the fire pit, a Rapid Phase Transition (RPT) all give indelible impressions. But training goes further, such as correctly setting up monitors and/or water screens, using foam to reduce the evaporation of an LNG pool, controlling an LNG fire, distinguishing between water vapour and BOG and measuring the explosion limits. Delegates who work with LNG can experience what happens when LNG is blocked in a pipe system, what to do in the event of a small leak, to recognize the different types of pipe insulation, increase tank pressure with a Pressure Build Up unit and experience how the various safety systems such as leak sensors and gas monitors work.
Thanks to the variety of training options and scenarios, RelyOn Nutec is able to offer a tailor-made programme based on the risks of the customer.
This is just one step in a series of developments in response training in the energy sector, such as hydrogen awareness, battery technology and solar panels.
For more information, go to www.relyonnutec-fireacademy.com
Liquefied Natural Gas (LNG)
Liquefied Natural Gas (LNG) is a mixture consisting mainly of methane with possible residual gases such as nitrogen, propane and ethane. Methane becomes liquid at normal pressure at cryogenic temperatures of about -162°C. Due to the lack of infrastructure for the transport of this natural gas, it is converted into LNG, making it approximately 600 times smaller in volume.
Gert Jan Langerak