LNG/LPG Subsea Loading Lines

Abstract

Cryogenic pipelines are emerging technologies that are essential for the new generation of offshore LNG (liquid natural gas) and LPG (liquid petroleum gas) loading and receiving terminals. For locations with sufficient deep water access close to the coast, terminals may consist of jetty structures and breakwaters, where tankers can be moored, and offloading can take place via the standard loading arms. Several LNG/LPG facilities have the jetty terminal connected to an onshore facility by a short trestle structure, which supports the product and utility piping and may in some cases support vehicular access to the terminal. As terminals move further offshore, there is a need to develop longer runs of insulated rigid pipeline transfer systems. As an alternate to the trestle‐supported piping, subsea pipelines may be considered. A subsea pipeline can be used to transport the product from/to an offshore terminal thereby eliminating the need and cost for a connecting trestle. The interest and rapid development in the transportation of LNG and LPG worldwide have prompted a fresh look at how these fuels transferred to/from a carrier that may be moored offshore in various locations. Cryogenic subsea loading lines are emerging technologies that are critical to a new generation of offshore LNG and LPG loading and unloading terminals. A comparison of the various subsea pipeline configurations being developed and available for use is discussed.