Design of an Offshore LNG Import Terminal
摘要
Natural gas (NG) is a hydrocarbon mixture consisting primarily of methane and ethane, both of which are gaseous under atmospheric conditions. After processing, the gas is cooled and converted to liquid at -162° C (LNG) to be transported by insulated tankers. At its destination, the LNG import terminal, the LNG is transferred from the moored ship to shore through pipelines connected to the ship's manifold. On shore the LNG is stored in insulated storage tanks, after which it can be 'regasified' and supplied to the customer. At the present time the construction of conventional onshore LNG import terminals encounters difficulties due to perception of unacceptable risk to public safety, long permitting processes and/or local environmental issues. An offshore terminal may offer a solution to overcome these problems. Already several studies on offshore LNG terminals have been carried out. In this thesis the feasibility of alternative, more cost effective concepts for offshore LNG import terminals will be discussed. The terminal should be based on a throughput of 5 million tonnes per annum and comprise of a fixed offshore LNG storage facility of 200,000 m3 with regasification equipment for high-pressure gas send-out and a mooring system that provides maximised terminal operability without constructing breakwaters.