SEPTEMBER 1, 2015 — Exhaust Gas Recirculation (EGR) potentially offers an attract alternative to dosing engines with urea in order to meet IMO Tier III limits on NOX emissions.
Japan's Mitsubishi Heavy Industries Marine Machinery & Engine Co., Ltd.(MHI-MME) and Mitsubishi Kakoki Kaisha, Ltd. continue to make progress with a low pressure EGR system developed under the Class NK Joint R&D for Industry Program.
As we reported in May (see earlier story), tests at Kobe Diesel on a MItsubishi 6UEC45LSE Eco B2 engine equipped with the MHI-MME EGR showed that it met the IMO III NOx limits and fuel economy targets.
The EGR equipped engine has since been installed in a 34,000 dwt bulker constructed by shipbuilder Hakodate Dock Co. for Shikishima Kisen K.K.
Yesterday, MHI-MME reported that sea trial results had confirmed satisfactory performance by the whole system. Now it will undergo verification testing on actual commercial voyages.
The MHI-MME Low Pressure EGR system changes combustion conditions inside an engine and suppress NOx generation by recirculating a part of the low pressure exhaust gas emitted from an engine turbocharger outlet to a turbocharger intake (the recommended branch point is after exhaust gas economizer/boiler) after being scrubbed by an EGR scrubber.
MHI-MME says that both initial and running costs are lower than those of a high pressure EGR system that utilizes high temperature and high pressure exhaust gas
The long-term verification testing will include confirming and evaluating the availability of the caustic soda and sludge disposal handling process required by the system.