First conversion to LNG completed
The product tanker MV Bit Viking has completed the first ever conversion worldwide, of a vessel from HFO to LNG and is now in service with Swedish owners Tarbit Shipping. Operating along the Norwegian coastline by Statoil. the very low emissions now attainable will qualify for lower Norwegian NOx emission taxes.
Caption: MV Bit Viking after conversion showing the two deck
mounted 17,850 ft3 (500 m3) Wärtsilä LNGPac tanks.
Image Credit: Wärtsilä Corp.
The Bit Viking has a very high safety specification. Delivered in 2007, the double hulled product tanker of 24,783 dwt has an LOA of 580 ft (177 m) and a beam of 82 ft (26.3 m). The original propulsion was with twin Wärtsilä 6L46B engines each with an output of 7,842 hp (5,850 kW) driving twin screws and features two separate engine rooms, double steering gears, rudders and control systems.
Apart from the modifications to the ship for the LNG refueling, storage and supply, the conversion required a major rebuild of the engines. The Wärtsilä 6L50DF engines with output of 7,460 hp (5,700 kW), although having the same stroke as the old engine, required increasing the cylinder bores from 460 mm to 500 mm and replacing most of the engine parts.
Operation of the engines on LNG uses Wärtsilä’s LNGPac system with two 17,850 ft3 (500 m3) LNG tanks located on deck. The tanks are of sufficient capacity to give an autonomy on LNG fuel of approximately 12 days on 80% load. As the engines are dual fuel, reverting to HFO operation is always and option.
The planning of the conversion project commenced in Mar 2010, docking and conversion work was in Aug 2011 and sea trials took place in Sept 2011. Safety analysis and approval was undertaken by Germanischer Lloyd (GL) classification society.
Caption: A Wärtsilä 6L50DF engine with output of 7,640 hp (5,700 kW).
Image Credit: Wärtsilä Corp
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