Wärtsilä Tests First Dual-Fuel Engine

Wärtsilä Corporation has successfully completed the factory acceptance test of the first Wärtsilä 50DF engine in a series of four dual-fuel engines for a 74,000 m3 LNG carrier. The LNG carrier is under construction at the French shipyard Chantiers de l'Atlantique for the French gas holding company Gaz de France. Due for delivery in 2004, it will be powered by four Wärtsilä 6L50DF dual-fuel engined generating sets which will meet all the ship's propulsion and shipboard electrical requirements. The Wärtsilä 6L50DF engines each develop 5700 kW at 514 rev/min. This will be the first LNG (liquefied natural gas) carrier to be powered by electric propulsion, and one of few to have internal-combustion engines instead of the more usual steam turbine plant. The tests of the Wärtsilä 50DF engine began in Finland early November 2002. The test program is designed to verify the functioning of the engine and for optimization of its performance. After thorough checks of all systems and running in, the initial data measurements were taken and the turbocharging system was optimized. The engine performance was then measured at steps from 15 to 100 per cent load. Adjustment of all engine functions then followed, particularly for trip to diesel operation, transfer to gas fuel operation, load acceptance and load rejection. The engine was tested mostly on natural gas but it was also run on low heating value gas and on gas with a low methane number. The factory acceptance test was witnessed by the ship owner, the ship operator, the shipbuilder and the classification society. The engine also successfully passed a type approval test witnessed by representatives from the classification society Bureau Veritas. Both tests included operation on gas fuel and light fuel oil (LFO), with tripping to diesel operation, transfer to gas fuel operation, load acceptance, and load rejection. Again it was also run on low heating value gas and low methane number gas. An important aspect was that all safety systems were tested. In August 2003, all four engines will be delivered to the shipyard for installation in the LNG carrier.