The fuel conversion of the product tanker »Bit Viking«, from heavy fuel[ds_preview] oil to gas operation, has been finalised and in October the vessel was handed over to the customer, Tarbit Shipping. The re-commissioned vessel is operated by Statoil along the Norwegian coastline and the conversion enables it to qualify for lower NOx emission taxes under 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, liquefied natural gas (LNG) operation means lower carbon oxide emissions and virtually no sulphur oxide or particle emissions whatsoever.
This is the first marine installation to involve converting Wärtsilä 46 engines to Wärtsilä 50DF engines and the first 50DF marine installation with mechanical propulsion. The scope of the conversion 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. 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. The two 500 m3 LNG storage tanks are mounted on the deck to facilitate bunkering operations and permit bunkering of LNG at a rate of 430 m3/h. The storage tanks provide the vessel with twelve days of autonomous operation at 80 % load, with the option to switch to marine gas oil if an extended range is required. When visiting EU ports, which have a limit of 0.1 % on sulphur emissions, the vessel operates on gas. The vessel’s classification certificate was also updated. It is the first LNG fuelled vessel to be classified by Germanischer Lloyd.
