MAN outlines Tier Ⅲ solutions

摘要

The international NOx emission limits on marine diesel engines as determined by MARPOL Annex VI are shown in Figure 1. Ships constructed after 1 January 2016 must not exceed Tier Ⅲ limits when sailing inside NOx ECA, except in cases where the area is designated later than the construction date of the ship. When sailing outside NOx ECA, the Tier II limits must be met. MAN Diesel & Turbo offers two alternative methods to meet the Tier Ⅲ NOx requirement on two-stroke engines. The first method, exhaust gas recirculation (EGR), is an internal engine process to prevent the formation of NOx by controlling the combustion process. The second method, selective catalytic reduction (SCR), is an after-treatment method using a catalyst and an additive to reduce the NOx generated in the combustion process. Figure 2 shows the layout of an EGR and SCR configured engine.