Bit Viking

Wärtsilä Oy has completed its first vessel conversion from heavy fuel oil to liquefied natural gas (LNG) operation. LNG fueled engines produce produce lower carbon oxide emissions and virtually no sulphur oxide or particle emissions. The vessel, the product tanker ‘Bit Viking’, is now able to qualify for lower nitrogen oxide (NOX) emission taxes under the Norwegian NOX fund scheme. Completed in October, the  ‘Bit Viking’ was handed over to the customer, Tarbit Shipping, for operation by Statoil along the Norwegian coastline.

This is the first marine installation in the world to involve converting Wärtsilä 46 engines to Wärtsilä 50DF engines, and the first 50DF marine installation with mechanical propulsion. By operating on LNG, the ‘Bit Viking’ becomes one of the most environmental friendly product tankers in the world.

In August 2010, Wärtsilä announced that it had signed a turnkey project with Tarbit Shipping to convert the ‘Bit Viking’ to LNG operation. The scope of the conversion package from Wärtsilä included deck-mounted gas fuel systems, piping, two six-cylinder Wärtsilä 46 engines converted to Wärtsilä 50DF units with related control systems and all adjustments to the ship’s systems necessitated by the conversion. The vessel’s classification certificate was also updated. The engines are connected directly to the propeller shafts through a reduction gearbox, thus avoiding the electrical losses that are an unavoidable feature of diesel-electric configurations. This enables a significant improvement in propulsion efficiency, reduced fuel consumption, and corresponding reductions in emissions. This is the first LNG fuelled vessel to be classified by Germanischer Lloyd.

New LNG storage system

The ‘Bit Viking’ utilises Wärtsilä’s new LNGPac system, which enables the safe and convenient onboard storage of LNG. The two 500 cubic metre LNG storage tanks are mounted on the deck to facilitate bunkering operations and permit the bunkering of LNG at a rate of 430 cubic metres per hour. The storage tanks provide the vessel with 12 days of autonomous operation at 80 per cent load, with the option to switch to marine gas oil if an extended range is required. When visiting EU ports, which have a 0.1 per cent limit on sulphur emissions, the vessel operates on gas.

“We are proud that the ‘Bit Viking’ is now one of the world’s most environmentally sustainable tankers in operation,” says Anders Hermansson, Technical Manager, Tarbit Shipping.

“The successful sea trials with this vessel provide yet further validation of the viability of LNG as the marine fuel of the future. We anticipate that this development will rapidly accelerate during the coming few years,” says Sören Karlsson, General Manager, Gas Applications, Ship Power Technology.