|Wärtsilä’s LBF specification. Click to enlarge.|
Wärtsilä was recently contracted by the STX Finland shipyard in Turku, Finland, to supply the main engines for a new multi-purpose cargo vessel. The vessel will be powered by three Wärtsilä 6L20 main generating sets, capable of operating on various types of liquid bio-fuels (LBF) fulfilling Wärtsilä’s liquid bio-fuel specification.
Wärtsilä’s engine technology offers flexibility which enables switching of fuels without any interruption in operation should the need arise. This will be the first installation in which a European commercial shipping operation is going to permanently use LBF as fuel. The liquid bio-fuel is produced at the ship owner’s process refinery in Uusikaupunki, on the south-west coast of Finland.
Common liquid biofuels approved for use in Wärtsilä engines are oils from various oilseeds, such as palm oil, palm stearin, rape seed oil, sunflower oil and jatropha oil. Liquid biofuels can also be of non-vegetable origin, i.e. oils or fats from fish, poultry and animals. Refined biofuel qualities such as transesterified biodiesel or hydrogenated renewable diesel can also be used, but Wärtsilä notes that crude LBF can be used instead of transesterified biodiesel or hydrogenated renewable diesel, giving a much better energy balance.
|Comparison of different fuels. Click to enlarge.|
The onboard fuel system is prepared for regular operation with LBF, and the sea acceptance trials for the owner are to be conducted using liquid bio-fuel.
The 6L20 genset has rated engine power of 1,100 kW (60 Hz) and generator power of 1,055 kW (60 Hz). Engine speed is 900–1,000 rpm, and per-cylinder output is 185 kW. Specific fuel oil consumption (SFOC) is 187 g/kWh.
The Aura II, scheduled to be delivered in spring 2012, will be a multi-purpose dry cargo ship that can also be used for oil recovery operations in the Baltic Sea. In addition, the ship is designed for the transport of heavy modules to the offshore industry in the North Sea basin. When not operating as a deck carrier, the 4,350 dwt ship is designed also as a container carrier.
Advanced training on the Wärtsilä engines will be provided to the operator crews at the Wärtsilä Land & Sea Academy training centre in Turku, Finland.
STX Finland is part of the international STX Europe Group. The ship is being built for Meriaura Ltd., a Finland-based provider of sea transport services for industrial products and general cargo.