Marine Engineering

Nitrogen oxides are the major air pollutants and pose a challenge to engine manufacturers to meet the limits set forth by the MARPOL Annex VI.  Combustion of fuels is the primary anthropogenic source of formation of nitrogen oxides, While Nitric oxide (NO) and nitrogendi-oxide are usually grouped together as NOx emissions, nitric oxide is the predominant oxide of nitrogen produced by combustion process. Therefore, it is an important minor species in the combustion because of its contribution to air pollution.  The principal source of NO is the oxidation of atmospheric (molecular) nitrogen. However, if the fuel contains  significant  nitrogen, the oxidation of the fuel nitrogen-containing compounds  is an additional source.  In the combustion of fuel that contains  no nitrogen , nitric oxide is formed by  three chemical mechanisms  that involve nitrogen from the air.  The  three principal mechanisms are: i) The th...

MARPOL Annex VI requires all diesel engines installed after 1st January 2000, with a power output of more than 130 kw to be tested and issued with an Engine International Air Pollution Prevention (EIAPP) certificate and an approved NOx Technical File.  The approved Technical File provides details of the allowable engine components settings, operating values and allowable adjustments which ensure the engine will continue to operate within the acceptable NOx emission limits.  This EIAPP certificate and approved Technical File stays with the engine and remains valid for its marine life.  Periodic verification surveys are carried out by the classification to confirm the engine continues to operate within the on-board NOx emission limits. If any adjustment, part replacement and modifications are carried out, which influences NOx emission characteristics should be recorded chronologically in an engine’s record book of engine parameters. ID numbers of all such compon...