Internal combustion (IC) engines and boilers are used on marine vessels for main propulsion and for auxiliary power and heating.
Large two-stroke diesel engines are used almost exclusively for propulsion on tanker fleets and container ships whereas cruise ships, ferries and supply vessels typically use medium-sized 4-stroke diesels for propulsion and auxiliary power alongside often in combination with boiler units.
Pollutant emissions from marine IC engines are essentially the same as for stationary applications. However, the heavier, high-sulphur, diesel fuels used tend to result in higher emissions - in particular PM, SOx and NOx. From 2015, SOx scrubber systems will be mandatory for all vessels operating in IMO-designated coastal areas (or SECA) for which Dürr LTB Sulfex DeSOx scrubber technology is suitable. All new builds from 2016 are also expected to have to install SCR technology to control NOx where Dürr LTB SCR systems could be applied.
Measures to control emissions of black carbon (PM) emissions - especially in sensitive areas such as the polar regions – is now also on the IMO agenda. Today, most line-haul locomotives, yard switchers (shunters) and DMU (diesel multiple units - without separate loco) are all typically powered by diesel-electric IC engine technology. Emissions from these engines are regulated, in particular, PM or soot. NOx will also be an issue in future although lack of space spaces and the need to pass through tunnels could prove an obstacle to the successful application of SCR Systems.