Bit Viking
The 25,000 dwt product tanker ‘Bit Viking’ was the first vessel ever to undergo a conversion by Wärtsilä from heavy fuel oil to liquefied natural gas (LNG) operation.
The unique fuel conversion of the product tanker ‘Bit Viking’, from heavy fuel oil to gas operation, has been finalised and in October 2011 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 carried out by Wärtsilä 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.
Tarbit Shipping is a Sweden-based company that has been transporting bitumen, petroleum products and chemicals since 1962. The company prides itself on its high level of environmental safety, and this conversion project is in line with this philosophy.
Bit Viking solution
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 % 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 %limit on sulphur emissions, the vessel operates on gas.
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