Mitsubishi Heavy Industries (MHI) and Mitsubishi Kakoki Kaisha have installed the first low pressure exhaust gas recirculation system for a two-stroke diesel engine, onboard a 34,000dwt bulk carrier built by The Hakodate Dock Co.
The exhaust gas recirculation system, which recirculates some of the low pressure exhaust gas from a turbocharger outlet back to the turbocharger inlet after scrubber treatment, was confirmed as meeting IMO Tier III NOx emissions in both factory and sea trials. It was originally developed under ClassNK’s Joint R&D for Industry programme.
The exhaust gas recirculation system is intended to keep both capital and operating costs lower than a high pressure system, which uses high temperature and high pressure exhaust gas from a turbocharger intake. Its effectiveness will now be verified on commercial voyages, while MHI and operator NYK Bulk & Project Carriers will also evaluate the availability of caustic soda, sludge disposal handling and other ancillary requirements to the system.
MHI said it would aim use its findings in the field to improve the whole system and prepare for the expanding Tier III market. The company has already developed another low-pressure NOx emissions abatement solution in its selective catalytic reduction (SCR) system.
“Consequently MHI-MME has two technologies adapted to IMO NOx Tier III for marine low speed two-stroke diesel engines,” the company said. “We will keep developing environmental technologies strongly to contribute to the reduction of worldwide maritime environmental burdens.”