Intercontinental maritime transport of LNG (Liquefied Natural Gas) has long been one of the mainstays of large-scale cryogenic applications. Export pipelines, 1-5 km long, from LNG liquefaction plants to transport vessels, operate in an essentially discontinuous mode. Transfer of 200,000m3 of LNG within 24 hours is required to minimize turnaround durations. This leads to metre-sized diameters as the pipelines operate at less than 10 bar.

ITP has developed an Invar-based (36%Ni alloy), double walled rigid pipeline technology that is compatible with buried and subsea applications, due to the limited thermal contraction. This is different to traditional in-plant stainless-steel piping on racks that requires expansion loops and is exposed to external attrition; Quantitative Risk Analysis shows that this type of construction is not compatible with populated or busy areas and lead to requirement for pipeline burial.

The paper will provide feedback from recent LNG pipeline construction projects in Asia and the United States, addressing the design requirements for double containment and showing the construction process in trenched and buried situations.

The technology is planned to be extended to colder temperatures, ie the -253°C of liquid hydrogen (LH2) instead of -163°C of LNG, with a view on transporting LH2 for intercontinental energy transfer (as with LNG) and refuelling of future zero-carbon emission airplanes. ITP has initiated a JIP to prove the material compatibility, finishing with the construction of a full-scale pipe to be tested with LH2. Feedback from the qualification programme progress will be provided.