Air Emissions



Air emission regulations introduced by the IMO, European Union (EU), U.S. Environmental Protection Agency (EPA) and other authorities aim to reduce harmful emissions from shipping for the benefit of human health and global ecosystems.  The ABS Environmental Performance team offers marine and offshore clients specialized guidance and comprehensive strategies to meet clean air and exhaust emission abatement goals. A lifecycle approach to performance optimization can be introduced in initial design and daily operations to achieve cost-effective environmental regulatory compliance. By implementing a holistic approach, environmental performance improvements may lead to enhanced operational efficiency through lower fuel costs and reductions in other fees.  ABS client-specific recommendations pull from the following portfolio of emissions-reducing tools:

Alternate fuels
Liquefied natural gas (LNG) may be considered as a competitively priced alternative to low sulfur fuel oil (LSFO). It also may play a key role in helping operators satisfy sulfur oxide (SOx) and possible nitrogen oxide (NOx) emissions standards in MARPOL-designated Emission Control Areas (ECAs). Additionally, ultra-low sulfur ECA compliance fuels and newer options of biofuels, hydrogen and other propulsion options (i.e., fuel cells, renewable energy, superconducting electric motors and hybrid propulsion) could be considered.

Exhaust Gas Cleaning Systems (EGCS)
EGCS are devices installed in the exhaust system after an engine or boiler. They treat the exhaust gas with a variety of substances, including sea water, chemically treated fresh water or dry chemicals, to remove sulfur oxides and achieve compliance with SOx requirements, as well as reduce particulate matter (PM) to some extent. After scrubbing, the cleaned exhaust is released into the atmosphere. Scrubber technologies create a waste stream requiring proper disposal.

Selective Catalytic Reduction (SCR)
SCR processes are used to remove NOx from exhaust emissions to meet MARPOL Annex VI, Tier III requirements. SCRs reduce NOx levels using ammonia as a reductant within a catalyst system prior to release into the atmosphere.

Exhaust Gas Recirculation (EGR)
EGR is a NOx emissions reduction technique used in diesel engines. The process works by recirculating a certain portion of exhaust gases back into the engine’s combustion chamber. This lowers peak temperatures and, thus, reduces NOx formation. EGRs may be integrated along with a SOx scrubber.

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