The IMO Tier III regulations require the reduction of nitrogen-oxide emissions (NOx) by approximately 76% in comparison to a Tier II engine. The IMO NOx-emission limits apply to all engines and depend on an engine’s maximum operating speed (n, rpm). Tier I and Tier II are global requirements, whereas Tier III standards only apply to current existing Emission Control Areas (ECAs) for NOx.
For WinGD X-DF engines, a low-pressure dual-fuel engine technology breakthrough has been realized. By applying the low-pressure gas concept, the investment in an expensive high pressure gas system is avoided, and no NOX reduction system is needed for operating in NOx emission control areas. To meet the low Tier III NOx emission limits, diesel engines necessitate an investment in NOX reducing technologies. For WinGD’s low-speed engines, SCR technology is offered with three solutions:
a) The off-engine high-pressure SCR (HP SCR) installed between the exhaust receiver and the turbocharger takes less space than low-pressure SCR but must be located in the engine room.
b) Integrated SCR (iSCR) provides high-pressure aftertreatment with an on-engine installation that reduces engine room space requirements, weight and integration complexity, as well as allowing for system validation before installation. It can be used for small- to medium-bore engines with one turbocharger that use low-sulphur fuels.
c) The low-pressure SCR (LP SCR) solution allows installation of the SCR reactor after the turbocharger outside of the engine room or in the stack.