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Reducing nitrogen oxide emissions

The new IMO NOx Tier II rules are active from 2011. The new NOx limit is 20% below the 2010 emission levels. All Wärtsilä portfolio products are today IMO NOx Tier II compliant. In addition, a global restriction of sulphur content in fuel will be limited from 2012 to 3.5%. In restricted SECA areas, a maximum sulphur content of 1% is in force from 2010.

The next emissions level, IMO Tier III, will be valid from 2016 onwards. This is expected to demand a reduction in NOx levels of 80% from Tier I levels. An 80% NOx reduction requires a step change in terms of engine technology and product offerings. Wärtsilä is looking into different solutions involving:

  • Engine internal technologies 
  • After treatment technologies
  • Fuel (Gas) related technologies

Development of all these technologies will be needed, as will the integration between them. A driving factor in this work is the lifecycle cost of the solution. Since lifecycle costs in 2016 are difficult to predict today, Wärtsilä is working on multiple solutions for meeting these future emission levels. Regardless of the technology preferred by our customers, Wärtsilä intends to have a competitive product in line with our status of being the preferred supplier.

Selective Catalytic Reduction (SCR) will play an important role in the future, and it is essential to ensure that combinations of SCR and scrubbers can be applied. Wärtsilä has experience in SCR systems with wide range of fuels. Wärtsilä is able to deliver also SCR solutions for high sulphur application with or without scrubbers. However, further development and commercialisation work will be carried out to optimise the system for a wider scope of applications, and will take into consideration various side effects and boundary conditions.