In South Korea, a national R&D project for development of Floating LNG Bunkering Terminal(FLBT) has been carried out. FLBT has a 220,000m3 storage capacity, which will be installed at a target offshore site with the internal turret and catenary mooring lines. It receives Liquefied Natural Gas(LNG) from a 170K LNG carrier(LNGC) and unloads LNG to 30K or 5K LNG-Bunkering Shuttles (LNG-BSs) simultaneously, as they are moored side-by-side with mooring ropes and fenders. The relative motion responses between loading arms and corresponding manifolds are crucial for LNG transfer process, because almost all rigid LNG loading arms have their specified allowable displacement criteria. To investigate the multi-body interactions, model tests were conducted at the ocean engineering basin in KRISO. Head sea and head quartering sea conditions were considered in the model test, while the different conditions of wave direction were covered by numerical simulations. Also, numerical simulations were conducted with AQWA, a sub-module of ANSYS package. The hydrodynamic coefficients obtained from the model test were used for AQWA simulation as input data. Finally we judged the operable incident wave heading range under allowable displacement criteria.
Due to the climate change caused by environmental pollution, regulation on sulfur and nitrogen oxides emission has been enacted by IMO. The most promising solution for this regulatory framework is to use LNG as a fuel on vessels. As a matter of fact, the demand for LNG fueled vessel is rapidly increasing. In this regard, bunkering terminals, which can be located at onshore or offshore, are essential for supply of LNG to LNG fueled vessels. In order to prepare this trend of industry demand, the Korea Research Institute of Ships & Ocean Engineering, KRISO has been conducting a government R&D project for technology development of FLBT. Basically, FLBTs can store LNG and transfer LNG to coming shuttles. In this project, FLBT is designed to operate near a specified port to receive LNG from LNGC, as well as unload to 30k and 5k LNG-BSs. Since LNG transportation is carried out from the ship to ship(STS) arrangement, the operability of FLBT strongly depends on the relative motion responses between the loading arm and corresponding manifold in given offshore environmental conditions. Specifically, through the model tests and analysis, operating heading range of FLBT in 1 year return period(l-YRP) was suggested.
