As part of the Life Mystic project, Nanni has developed a marine engine that runs on both diesel and methanol. The drive is based on a 6-litre unit from John Deere and is used as a generator unit. The development was carried out in collaboration with ScandiNAOS AB from Gothenburg, a company specialising in methanol conversions. The International Maritime Organisation (IMO) is calling for a significant reduction in pollutant emissions in shipping, which is why Nanni developed this technology.
How the dual-fuel system works
The engine runs on a fuel mixture of around 30 per cent diesel and 70 per cent methanol in terms of energy content. ScandiNAOS developed a conversion kit with a methanol control system and customised injection technology for this purpose. The system makes it possible to switch between pure diesel operation and dual-fuel mode during operation. When the methanol tank is empty, the engine automatically switches to pure diesel operation without interrupting performance. This flexibility makes the drive suitable for applications where methanol is not always available.
Test results and emission values
The tests were carried out in accordance with the standards of the IACS, the International Association of Classification Societies. A representative of the Italian classification society RINA supervised the tests. According to the manufacturer, the engine switched smoothly between operating modes. The proportion of methanol in the energy mix is between 50 and 75 per cent, depending on the load point. Full power is available in both diesel and dual-fuel operation. The converted engine has shown significant improvements in emission measurements: Carbon monoxide and hydrocarbon emissions had fallen by 95 to 99 per cent, and nitrogen oxide levels by 65 per cent across most load ranges. According to Nanni, particulate emissions are also consistently lower.
Methanol as an alternative fuel
Methanol is considered a promising alternative fuel in the shipping industry. The alcohol can be produced from various sources, including renewable energies. Compared to conventional marine diesel, methanol burns cleaner and produces fewer soot particles. The fuel is liquid at room temperature and can therefore be handled in a similar way to diesel. However, methanol contains less energy per litre than diesel, which is why larger tanks are required. Dual-fuel technology combines the advantages of both fuels: emissions are reduced by the methanol content, while diesel serves as an ignition source and ensures availability.
Technical implementation of the conversion
In addition to the control system, the ScandiNAOS conversion kit also includes hardware modifications to the fuel system. The methanol injection was integrated into the existing system. The engine retains its original performance data, but can now run on two different fuels. The switch between modes is automatic, based on the availability of methanol. This solution allows operators to gradually switch to the alternative fuel without having to sacrifice the reliability of diesel. Nanni describes this engine as the first high-speed dual-fuel drive developed in-house.
Jan-Ole Puls
Editor Test & Technology
