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Encyclopedia of Marine and Energy Technology

LNG re-gasification vessel GDF SUEZ NEPTUNE


GDF SUEZ NEPTUNE was built by Samsung Heavy Industries (SHI), Korea, and delivered to her operator Hoeg LNG, on 30th November 2009. The vessel has a transport capacity of some 145,000 m3 and a contract price of about $290M.

Compared to a standard LNG carrier the vessel has a number of additional features including three skid-mounted re-gasification units supplied by Wärtsilä Hamworthy, turret mooring and discharging arrangements, as well as specialized equipment to reduce and contain emissions to air and water during the cargo processing and handling cycle.

The onboard vaporization plant allows the ship to convert her liquefied cargo back into the gaseous state, for direct transfer ashore into the natural gas distribution grid. The discharge can be accomplished offshore using submerged turret technology.

In the cargo dispatch process, LNG is pumped from the tanks to the re-gasification units on the weather deck offering a re-gasification capacity of 210t per hour of LNG with a send-out pressure of 115 bar. Pressure is boosted using cryogenic LNG pumps, and steam generated by auxiliary boilers. The re-gasified LNG is discharged via a turret and swivel through a mooring and unloading buoy connected to riser and subsea pipeline.

Since its specification for the first, pioneering dual-fuel-electric LNG carriers, commissioned in 2006, the Wärtsilä 50DF engine has become the prime mover of choice in LNGC electric propulsion systems. Four Wärtsilä 50DF engines drive the ABB generators, three rated at 12,941kVA and one at 6470kVA. The prime movers are three 12-cylinder vee-form engines and one six-cylinder in-line engine, in aggregates delivering electrical energy to a pair of ABB 13.2MW propulsion motors and other shipboard consumers. The motors drive a single, fixed pitch propeller via a gearbox. The multi-engine, electric propulsion plant gives a high degree of operating flexibility. SHI claims that this system provides 30% higher efficiency that the more common steam turbine system.

ABB delivered a complete, fully integrated electrical system package. Besides the four synchronous-type, 6.6kV main generators, two synchronous-type propulsion motors and associated ACS6000 drives, four propulsion transformers and propulsion control system, two main switchboard, one re-gasification and two cargo switchboards, two thruster motor starters, and other equipment.

Length, oa: 283.06m, Length, bp: 270.00m, Breadth, mld: 43.40m, Depth to main deck: 26.00m, Draught design/scantling: 11.4/12.4m, Deadweight design/scantling: 70,860/80,980dwt, Service speed (21% sea margin): 19.5knots, Cargo capacity: 145,130m3, Main engines: 3 x Wärtsilä 12V50DF + 1 x Wärtsilä 6L50DF, Propulsion motors: 2 x ABB A/S 13,200kW.

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