Moving LNG production to an offshore setting certainly presents a serious set of challenges for the offshore oil and gas industry, particularly when it comes to the design and construction of FLNG facilities which need to maintain the utmost levels of safety and give increased flexibility to LNG production while withstanding the effects of winds, waves and currents in the open seas. With the first FLNG plants now in production and twenty other planned FLNG projects worldwide, it is safe to say that over the past few years these challenges have been overcome and these facilities have well and truly demonstrated their economic and technical viability to the industry. But while some challenges have certainly been met, others remain.The environmental conditions of the current FLNG locations are at present quite mild and only require the use of the most straightforward technology for the unloading of the LNG, e.g. marine loading arms. But, with prospective new FLNG locations moving away from these 'mild' areas, to sites where sea states, wind and currents can be much more severe, only tandem LNG offloading systems appear to meet the challenges of the application as they improve safety, operability and availability.Since 2009, Trelleborg has been developing floating cryogenic hoses which ensure LNG offshore transfer with minimum BOG generation, combine high flexibility, reliability and long service life, and also meet LNG operator and contractor's offloading requirements related to safety, flowrate capacity and operation availability. Through latest acquisition, this technology has been even further enhanced, with new parameters being put forward for the development of these hoses in order to become a key component in offloading systems for future offshore FLNG projects.This white paper will discuss Trelleborg's 20Љ ID cryogenic hose development and qualification program and outline why tandem offloading solutions are a viable alternative for the industry -not only limiting downtime, but also improving safety. The paper will present in this case the innovative offshore LNG offloading system using cryogenic floating hoses which has been jointly developed with Saipem since 2009 and about to be qualified according to EN1474 standard requirements.

The LNG market remains in relative infancy in terms of the development of infrastructure to meet increasing supply and demand. Given its unique make-up compared to traditional oil and gas transposition, new and innovative means of transferring LNG have had to emerge; factoring the unique composition of LNG (i.e. chemical and physical properties) and the critical importance of safety while loading and unloading. Moreover, LNG Infrastructure is moving into new frontiers for a variety of reasons. LNG exporters are seeking new markets and evolution of small and medium scale LNG demand will necessitate splitting of LNG into smaller load parcels. Power generation, and LNG terminals, are being constructed in locations that have traditionally been ‘off-grid’ – disconnected from pipelines. More flexible options are required to fit a broader range of vessel sizes, locations, weather conditions and infrastructure conditions. One key element in unlocking new transfer options is fresh thinking around ship-to-shore transfer and the development of game-changing floating composite cryogenic hose technology. Composite LNG hoses typically consist of multiple, unbonded, polymeric film and woven fabric layers encapsulated between two stainless steel wire helices – one internal and one external. Essentially, the film layers provide a fluid-tight barrier to the conveyed product, with the mechanical strength of the hose coming from woven fabric layers. The number and arrangement of multiple polymeric film and woven fabric layers is specific to the hose size and application. The polymeric film and fabric materials are selected to be compatible with the conveyed product and the operating temperatures likely to be encountered. This technology cost-effective technology has enabled a recalibration of traditional thinking around ship-to-shore LNG transfer. Designed for fatigue resistance in even the most hazardous conditions, cryogenic floating hose technology typically provides a viable alternative to traditional jetty-based transference in circumstances that would make such infrastructure unfeasible – for example, harsh environments, areas where water is too deep to accommodate jetty construction, or too shallow to allow large vessels to moor alongside. These cryogenic hoses also expand options for offshore ship-to-ship transfers in a broader range of locations; for example, in tandem configuration, vessels can be moored as much as 300 to 500 meters away from a storage unit. This enables ship-to-ship transfer in deeper waters in even the most challenging conditions - with the increased separation distance mitigating the risk of collision and ensuring the safety of the vessels and crew. In this paper, we will discuss the multiple applications of cryogenic floating hose technology and how it is re-shaping ship-to-shore and ship-to-ship transfer.