Exhaust Emission Abatement

ABS Guide on Exhaust Emission Abatement

Download guidance for the design and construction of exhaust emission abatement systems, focusing on SOx scrubbers, SCR systems, and Exhaust Gas Recirculation (EGR) arrangements, applicable to all vessel types.

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Exhaust Emission Abatement

International, regional, national and local air emissions legislation is driving the development of primary engine technologies and secondary exhaust emissions abatement systems to reduce exhaust emissions from ships. These techniques are primarily aimed at meeting IMO MARPOL Annex VI Regulations 13 and 14 requirements for nitrogen oxide emissions from diesel engines and sulfur oxide emissions from all fuel-burning equipment on board.

A number of techniques and design features are used by diesel engine manufacturers to reduce NOx emissions. However, to achieve compliance with the IMO Tier III limit (effective in the North American NOx emission control areas since January 1, 2016), it is anticipated that the predominant exhaust emission abatement technologies used will be Exhaust Gas Recirculation (EGR) or Selective Catalytic Reduction (SCR) systems.

The IMO limits SOx emissions by regulating the sulfur content of marine fuels, and it is anticipated that the reductions in the emission control area and global sulfur limits to 0.1% and 0.5%, effective from January 1, 2015 and January 1, 2020 respectively, will promote increasing use of exhaust gas cleaning systems, such as SOx scrubbers.

In all cases, the air emissions performance testing, statutory certification, and statutory survey aspects are regulated through Annex VI in association with any applicable IMO Guidelines. At the time of issuance of this Guide, the applicable Guidelines for Selective Catalytic Reduction are IMO Resolution MEPC.198(62) – 2011 Guidelines Addressing Additional Aspects to the NOx Technical Code 2008 With Regard to Particular Requirements Related to Marine Diesel Engines Fitted With Selective Catalytic Reduction (SCR) Systems, adopted July 15, 2011 and as amended by IMO Resolution MEPC.260(68), adopted May 15, 2015. The applicable Guidelines for SOx exhaust gas cleaning systems are IMO Resolution MEPC.259(68) 2015 Guidelines for Exhaust Gas Cleaning Systems, adopted May 15, 2015. Acceptance of a SOx exhaust gas cleaning system is regulated as an alternative under MARPOL Annex VI Regulation 4 and is subject to approval by the flag Administration of the vessel.

ABS has developed a guide to provide guidance for the design and construction of exhaust emission abatement systems. It focuses on SOx scrubbers, SCR systems, and Exhaust Gas Recirculation (EGR) arrangements, and may be applied to all vessel types. An exhaust emission abatement system is considered to be fully approved upon verification of compliance with both the ABS requirements and the applicable IMO Regulations and Guidelines. The Guide covers only the Classification approval aspects, and statutory approval would be made by ABS as a separate parallel process in the capacity of a Recognized Organization for the vast majority of flag Administrations.

The optional exhaust emission abatement notations detailed under 1/9.3 through 1/9.9 will be assigned upon request and where the exhaust emission abatement system has been verified to be in compliance with the applicable requirements of the Guide. Where a notation has not been requested, the exhaust emission abatement system is to be verified to be in compliance with the requirements prescribed under 1/9.11 of the Guide.