Offshore LNG transfer systems for standard carriers in shallow water

Due to a global increasing demand for efficient clean energy sources the demand for natural gas is predicted to grow considerably this decade. Natural gas is transported by pipeline on the shorter distances and as LNG on longer distances. LNG (Liquefied Natural Gas) is produced by cooling natural gas to just below its boiling point at -162 ·C. It is stored and transported in thermally insulated tanks at ambient pressure. Currently the LNG fleet exists of 127 vessels of which the majority have a capacity between 125,000 m3 and 135,000 m3.The majority of the vessels are project controlled in long-term lease contracts: cuurentlyanother54 vessels are on order to expand the fleet in order to meet the expected growth in transport volume. At this moment there are 39 reception terminals, of which 23 are located in Japan the largest importer of LNG, and there are plans for another 25 terminals. The main emerging markets for LNG are the U.S., India and China. In a conventional reception terminal, an LNG carrier is moored to a jetty. When the LNG carrier is offloaded the vapour that is suppressed from the storage tanks is send to the ship. The investment costs for conventional terminals vary between USD 180 mln and USD 650 mln, depending on the annual throughput, storage capacity and location. The breakwater, storage tanks and regasification plant are the most expensive components of the terminal. For offshore LNG reception terminals it is most economic to locate storage tanks and the regasification plant onshore. Based on technical feasibility, novelty aspects and safety 3 designs out of 12 have been selected for analysis of the vessel motions and the mooring forces.Hydraulic EngineeringCivil Engineering and Geoscience