The product tanker Bit Viking is the first vessel ever to have undergone a conversion from heavy fuel oil to liquefied natural gas (LNG) operation. Through the conversion the vessel now qualifies for lower nitrogen oxide (NOX) emission taxes under the Norwegian NOX fund scheme.
The conversion has been finalised and in October the vessel was delivered to Tarbit Shipping. The re-commissioned vessel is operated by Statoil along the Norwegian coastline. Wärtsilä carried out the conversion that was undertaken to qualify for the Norwegian NOX fund scheme. The fund is a cooperative effort whereby participating companies may apply for financial support in return for introducing NOX reducing measures. Furthermore, LNG operation means lower carbon oxide emissions, and virtually no sulphur oxide or particle emissions.
First Marine Dual Fuel (DF) Conversion
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 environmentally friendly product tankers in the world.
Scope of the Conversion Package
The contract between Wärtsilä and Tarbit Shipping for the conversion was signed in August 2010. The scope of the conversion package 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.
Picture: The Bit Viking is now one of the most environmentally friendly product tankers in the world (picture by Tarbit Shipping)
