The Finnish marine technology supplier Wärtsilä and Swedish shipping company Furetank are co-developing and testing two technologies showing the potential to halve the methane slip, according to Furetank's release.
Running vessels on LNG/LBG brings many benefits compared to conventional fuel oil, reducing emissions of CO2, NOx, SOx and harmful particles. But a much debated downside is the methane slip: the release of unburned gas fuel, not fully combusted in the engines.
Although the combustion rate is generally high and the methane slip accounts for a very small fraction of the fuel used, methane is a more potent greenhouse gas than CO2. Thus, this slip is the most critical technical challenge to overcome in gas-fueled vessels; a challenge which Wärtsilä and Furetank are now countering.
Two technical solutions have been tested in Furetank’s Vinga series tankers. One of them is a Greenhouse Gas (GHG) reduction package, developed by Wärtsilä for dual fuel engines. The GHG package actively controls the engine while working in demanding conditions like manoeuvring, harsh sea conditions or varying fuel quality. This way, combustion is optimized and unburned gas emissions minimized.
The other solution is the Low Load Optimization package, reducing the methane slip at low engine loads, for example during harbour operations like loading and unloading. This package actively balances the loading of each engine cylinder, optimizing the overall total engine efficiency even at a low engine load.
The tests performed, both in the laboratory and at sea, show very promising results. The methane slip was reduced by 45-50%.
Furetank, based on Donsö in the Gothenburg archipelago, is a Swedish, family-owned shipping company active in tanker shipping since the early 1950’s. Furetank operates 9 owned vessels and is a founding member of the Gothia Tanker Alliance: a market platform for small and intermediate product tankers, operating 40 vessels in European waters.