The proposal for an exhaust cleaning system preferred by MAN Diesel & Turbo, the Exhaust Gas Recirculation (EGR) system, is facing its decisive test during the year to come. Today or tomorrow, the system will be shown on the main engine for installation in one of the new smaller Maersk Line container ships at the Hyundai shipyard in South Korea giving the Danish-German engine manufacturer valuable information on the system. The test will be the first of the system on a commercial ship and will secure MAN with an advantage in the market before the new IMO regulation curbing the emissions of NOx will come into force in 2016.
The EGR system prevents NOx from being made in the engine whereas traditional exhaust smoke cleaning systems remove the NOx being made which is the case with e.g. SCR, Selective Catalytical Reduction. The principle of EGR includes taking a part of the exhaust gasses from an engine, cooling it down, cleaning it and sending it back into the engine. As exhaust gasses contain less oxygen and more carbon dioxide than pure air, the EGR process results in a smaller concentration of oxygen and a higher concentration of CO2 inside the combustion chamber, lowering the temperature which prevents Nox from being produced.