MAN Diesel & Turbo to supply G-type Tier III-Compliant Engines for 2 lightering vessel newbuildings powered by MAN B&W 6G70ME-C9.2 prime movers.
The newbuildings will each use an MAN Diesel & Turbo EGR (Exhaust Gas Recirculation) system to help their ME-C prime movers meet Tier III emission standards well in advance of requirements coming into effect. The engines will also retain the ability to switch to Tier II operation when outside the ECA (Environmental Control Area).
The engines for the first vessel have a delivery date in December 2012, with the second due in early 2014, with the vessels due for delivery in 2014. Chevron has also ordered 1 × MAN 8L27/38 + 2 × MAN 7L21/31 gensets for each vessel and Doosan Engine will construct these, along with the G-type engines, at its works in Korea.
Generally, ships use HFO as fuel, which contains sulphur and forms NOx and SOx during combustion. MAN Diesel & Turbo’s EGR system ensures full fuel flexibility, ranging from HFO to distillates and natural gas, and reduces NOx by directing part of the exhaust gas back into the engine’s scavenge air. This reduces the oxygen content of the air in the combustion chamber, thereby lowering the combustion temperature and, as a result, reduces NOx formation.
Tests at MAN Diesel & Turbo’s Diesel Research Centre, Copenhagen have shown that EGR alone can achieve the IMO’s forthcoming Tier III NOx emission requirements.