DECREASING EMISSIONS OF NITROGEN OXIDES WITH EXHAUST GASES OF MARINE DIESEL ENGINES

Solving the problem of ocean's airspace polluting with harmful emissions of ship-generated diesel engines by exhaust gases is associated with the creation of highly effective technologies for the neutralization of nitrogen oxides NOx from the diesel plant that apply both to vessels in service, designed and built. The air entering the engine is a working fluid that carries out a certain thermodynamic cycle, resulting in a change in its chemical composition, and the exhaust gas mixture contains many components. Emissions of harmful substances during the combustion of marine fuels are limited in accordance with international programs for the protection of the atmosphere and requirements of the International Maritime Organization IMO. Requirements apply all groups of harmful emissions of marine engines. The most stringent of them concern nitrogen oxides NOx and sulfur oxides SOx. To reduce harmful emissions from the exhaust gases into the environment, scientists and world leaders in engine construction, such as MAN Energy Solutions and Wärtsilä, apply and offer a variety of techniques to reduce the number of harmful substances in the exhaust gases. One of the most promising is the exhaust gas recirculation system (EGRS) of the ship diesel engine. Its advantage over other methods is the insignificant impact on the operation of the engine. During the exhaust gas recycling a temperature of the flame in the combustion chamber decreases, which leads to the reduction of NOx number. This is a consequence of the high rates of carbon dioxide and water vapor. Since the combustion rate is reduced, the exhaust temperature and the thermal load on the engine part are increased. The dilution of the inflow air with waste gas reduces the oxygen content in the supercharged air from 21 to 13%. The possibilities of the technology of the system of recirculation of exhaust gases of a marine engine are limited by the value of the ratio of O2/CO2 in the intake air, due to which the amount of combustion products at the inlet is limited to no more than 30%