Briefly describe the environmental impact of NOx and SOx and allowable limitations as per MARPOL Annex VI in emission control areas and outside, and methods to control NOx emission?
Short answer
| Pollutant | Environmental impact | Global limit | ECA limit |
|---|---|---|---|
| NOx | Acid rain, smog, respiratory disease, ozone depletion | Tier I/II: 17.0/45·n^(-0.2)/9.8 or 14.4/44·n^(-0.23)/7.7 g/kWh | Tier III: 3.4/9·n^(-0.2)/2.0 g/kWh |
| SOx | Acid rain, respiratory disease, particulate matter | 0.50% m/m sulphur | 0.10% m/m sulphur |
- NOx impact: acid rain, smog, respiratory disease, ozone depletion
- SOx impact: acid rain, respiratory disease, particulate matter
- NOx limits global: Tier I 17.0/45·n^(-0.2)/9.8 g/kWh, Tier II 14.4/44·n^(-0.23)/7.7 g/kWh
- NOx limits in NOx ECA: Tier III 3.4/9·n^(-0.2)/2.0 g/kWh
- SOx limits: 0.50% m/m globally, 0.10% m/m in SOx ECA
- NOx control methods: SCR, EGR, water emulsion, engine parameter tuning, LNG fuel, direct water injection
- Governing instrument: MARPOL Annex VI Reg 13, Reg 14, NOx Technical Code 2008
Full answer
The full answer explains each point step by step, with the regulations and figures behind it and the discussion from other candidates. It is in the ETO section of the Marine One forum, open to members enrolled for the ETO exam.