Subsea cryogenic pipelines (LNG/LPG)

The natural gas industry has an impressive growth record and is often dubbed as energy source of the 21st century owing to its abundant reserves, low carbon dioxide emissions and the high efficiency of utilization

But, supply of natural gas to most regions of the world requires transportation by sea in highly sophisticated carriers able to transport gas under its liquid form, at cryogenic temperature (-160°C). These ships require dedicated marine terminals especially designed to export or relieve this cargo. Suitable land sites to build these LNG terminals must be close to the markets, easily accessible to ships and environmentally acceptable.

The traditional solution to transport cryogenic products for transferring LNG cargo to and from the LNG carrier is an insulated pipe laid on a trestle. ITP has designed and qualified an innovative and environment-friendly solution based on a subsea pipeline that eliminates the need of building a costly trestle.

The ITP subsea pipeline has already been implemented successfully for LPG transportation in Peru for the Camisea project to connect the onshore fractionation plant to the offshore berth.

The ITP LNG pipe technology has gone through a formal qualification process that was sponsored by five major oil and gas companies. The technology is now fully qualified and has been certified “Fit for Service” by DNV (DNV Certificate of Fitness for Service).

The transportation of LNG through the ITP pipeline system (either onshore underground or subsea) will revolutionize siting options, safety, security, visual appearance, and economics of LNG import and export terminals.

ITP offer an innovative solution for subsea transfer of LNG between ship and shore, reducing the costs, minimizing the risks and maximizing the security and the application compared to a standard jetty offloading system.

Concept

The ITP LNG pipe technology is a triple-wall pipe or Pipe-in-Pipe-in-Pipe (PiPiP) as shown in the figure below.   The utilisation of a 36% NiFe inner pipe, commonly known as Invar, allows a significant reduction of the thermal contraction of the inner pipe resulting from the temperature differential between the -160ºC operating temperature and the ambient temperature. Two other pipes (intermediate and outer pipes) surround the 36% Nife pipe to protect the inner pipe and insulation and to ensure maximum security. The microporous material, IzoflexTM is used for its superior thermal performance and its load bearing properties which act as a continuous centralizer in the pipe-in-pipe annulus.

ITP LNG Triple Pipe Design

Advantages The advantages of going subsea compared with a traditional pipe on a trestle are multiple and range from an increased safety to a lower cost. The advantages are detailed below: Safety / Security - The marine facilities are less exposed. - Out of sight, out of mind. As the pipe is not visible, it is less likely to be a target. - It is possible to move the terminal further away from the coast, where no dredging is required. - The triple wall pipe option ensures a better protection against external damage. - The PiPiP can handle challenging marine conditions

LPG carrier moored at jetty head for LPG loading

Costs reduction - Straightforward, robust design - Reduced boiled-off rates - Avoids heavy civil work associated to a trestle jetty. - Eliminates expansion loops or bellows Environment - No visual impact from shore (see animation below). - No impact on local marine traffic. - No contamination by non-native plant/animals, coming form the LNG carriers. Applications - Subsea - Underground (buried) - On a trestle

Camisea “flat-pack” before offshore towing