Operability of an LNG tandem offloading system

摘要

Floating natural gas liquefaction plants (FLNG) have proven to be a relevant, efficient and economical way to develop stranded gas reserves. However, they still represent a huge investment for an operator, which means that performances and reliability of the facility must be up to the highest standards and that design studies must demonstrate the reliability of the whole system. In particular, the availability and operability of the LNG offloading system on an FLNG is a major concern since those systems have not been operated in offshore applications yet. Besides, frequent offloading downtime can generate operating difficulties or constraints such as LNG tanks buffer management operations, turn-down or ultimately shut-down of the liquefaction plant. Following this approach, TOTAL decided to investigate the operability of the LNG tandem offloading system developed by SAIPEM, using TRELLEBORG cryogenic floating flexible hoses. Inspired from oil tandem loading operations, the system has been designed to match the specific requirements of LNG transfer and to operate in exposed offshore areas more challenging than those considered for offshore marine loading arms. During LNG loading operations, three hoses are connected to an LNG carrier fitted with bow loading platforms that house mooring and hoses connection devices.