First Wärtsilä X62DF for LNG carrier

The six-cylinder engine is the first for a series of 180,000m3 very large gas carriers under construction by Samsung Heavy Industries for SK Shipping Co and Marubeni Corp. During the demonstration the engine’s design fuel consumption, Tier III NOx emissions compliance (in gas mode) and stable running at a wide range of engine loads were confirmed.

WinGD and Doosan noted that capex savings of 15-20% are possible as a result of the low-pressure fuel gas handling system, which delivers LNG to the engine at below 16 bar. For LNG carriers, no high-pressure gas compression system is needed to use boil-off gas, reducing operating cost.

Stable operation on gas from 5% to 100% engine load means that there is no need to increase liquid fuel injection under any situation where sufficient gaseous fuel is available. Pilot fuel consumption accounts for around 1% of total heat released during combustion, said to be lower than other low-speed dual-fuel engines.

As reported, the engines will feature a fuel sharing mode from late 2016, enabling operators to use liquid and gaseous fuel at the same time if economically viable at a given time. The first engine employing WinGD’s X-DF technology with low-pressure gas admission, an RT flex50DF, has already completed type approval testing.