Sulphur emissions cannot be reduced by measures inside the engine. The rule of thumb used by engineers – “sulphur in – sulphur out” – is a way of succinctly expressing the fact that the proportion of sulphur in fuel equals that expelled in the exhaust gas. Only the use of low-sulphur fuels or aftertreatment systems such as exhaust gas scrubbers, therefore, can provide a solution to this.

 
A key feature of our two- and four-stroke diesel engines is their fuel flexibility. MAN Diesel & Turbo engines are usually optimised to run on heavy fuel oil, but can also easily be converted to fuels with low sulphur content such as marine diesel oil, gas oil or biodiesel. Natural gas, a resource which is almost sulphur-free, can also be used as a fuel, for example in our dual-fuel engines.

On board ships, it may be possible in future to run the engines needed for power generation and propulsion on natural gas. This would not only reduce the amount of SOx in the exhaust gas to almost zero, but could also cut the NOx, particle and CO2 emissions significantly.