It's ironic that considering the gargantuan proportions of the Prelude floating liquefied natural gas (FLNG)project, it's actually its outstanding representation of miniaturization that makes it truly unique. At over half a kilometre in length and displacing more water than six aircraft carriers, Prelude would stand higher than the Petronas Towers in Kuala Lumpur if you stood her on end. Yet the footprint of the vessel is just a fraction of that of a land-based gas plant, it doesn't use valuable land for pipelines and every year it will produce more LNG than Hong Kong uses annually.
With a lifespan of at least fifty years, Prelude is described by Shell Oil as an environmentally friendlier alternative to an onshore LNG refinery. After all, it can be redeployed to new fields and uses 50% less materials and has 95% less land and seabed disturbance than land-based refineries.
FLNG is a revolutionary technology that will allow Shell to access offshore gas fields that would otherwise be too costly or difficult to develop; in this case in the Browse Basin, 475 km northeast of Broome, Australia. Cooled to -162° Celsius (-260°F), the natural gas shrinks to 1/600 of its volume when it is turned into LNG. Prelude will remain on location off Australia for 20-25 years to develop gas fields in the Browse Basin.
The project is requiring a re-think of how super-sized parts are forged. For example one of the solid duplex Gas Production Swivel Outer Parts measured 2990mm outside diameter and had a forged weight of 17200 kg! New technologies such as thermally sprayed aluminium coating on duplex are also being deployed to extend the life of parts.
Contact the Editor in Chief, Mrs Joanne McIntyre at
j.mcintyre@kci-world if you'd like a pdf of a full article on Prelude, based on interviews with Anthony Pearson of SBM Offshore and Andrew Barnes Shell Global Solutions.