Assessing Integrity and Reliability of Multicomposite LNG Transfer Hoses

Abstract Reliable transfer systems are a key element in developing floating LNG and thesmall scale LNG market. Multi-composite hoses may prove to be a reliable andcost effective solution for offshore, near- and on-shore applications. TNO, theDutch contract research organization, has executed an extensive test program onthe multi-composite hose of Gutteling B.V. for Ship-to-Ship (STS) LNGtransfers. It has resulted in the qualification of a hose as a product inaccordance to EN1474-part 2. This paper summarizes the test program. Transfersystems needs to be qualified in accordance with EN1474-part 3 which applies arisk based approach. Moreover in order, to provide data to support systemqualification, a complementary test program was performed focused on thebehavior under off-spec conditions. The growing range of composite LNG hoseapplications and the growing interest of industry raise questions on theintegrity and reliability over service life. The paper reviews what factorswill affect the reliability over service life. Mechanical fatigue and creep areidentified as the potential critical failure mechanisms. The paper proposes anapproach to modeling fatigue and creep performance to support thesubstantiation of the hose reliability over service life. Having commonlyaccepted engineering models available will enhance the further application ofcomposite hoses in the floating LNG and small scale LNG market. Introduction Transfer systems are a crucial enabler for floating LNG [4], [5]. To offloadLNG offshore, various aerial and floating transfer systems are currently underdevelopment [6], [7]. Some are based on loading arm technology, others on metalflexible pipe or multi-composite hoses. The multi-composite hose consists ofhelical wires, thin liquid tight films of polymeric materials and layers offabric like polymeric materials. For floating hoses the composite hose iscovered with insulation and a polymeric outer hose. Similar composite hoses arefrequently used in the oil and chemical industry for transfer. As such, thecomposite hose technology is not new. However, reliability and safetyrequirements and the cryogenic temperature during operation makes the LNG hosea class on its own.