Exhaust gas cleaning system developed in Japan

13 Feb 2014
Cleaner marine diesel exhaust is now likely in Japan

Cleaner marine diesel exhaust is now likely in Japan

Mitsubishi Heavy Industries and Mitsubishi Kakoki Kaisha (MKK) have jointly announced the development of a so-called ‘Hybrid SOx Scrubber System’ to remove SOx from marine diesel engine exhaust gas.

The system is said to be the first in Japan to comply with the 2015 ECA SOx emission regulations. It will thus allow ships to continue to burn lower-cost HFO in ECAs rather than having to switch to more expensive distillate fuels. Adoption of modular design principles should allow the system to be retrofitted to ships already in service.

According to MHI, the hybrid system combines two scrubbing systems, one that uses re-circulating fresh water and the other using sea water in a one-pass flow system. The freshwater system is claimed to be capable of scrubbing exhaust gas from combustion of HFO with 3.5% sulphur content to the equivalent emission levels of 0.1% sulphur fuel, achieving compliance with IMO SOx emission regulations scheduled to enter into effect in ECAs in 2015. The seawater system is said to be able to scrubbing exhaust gases to a level equivalent to 0.5% sulphur content fuel oil, thus complying with future global Sox emissions regulations. The seawater that has been used for washing is treated before discharge to comply with requirements for discharged wash water.

The complete system comprises a SOx scrubber, a container unit housing the wash water processing system and other components, and ISO standard tank containers to store sludge and a caustic soda solution (NaOH) to neutralise circulating fresh water. Modular construction enables flexible arrangement of components, which the company says should reduce installation time and cost, particularly for retrofit installations.

MKK has, for many years, been providing industrial flue gas scrubbing systems for removal of sulphur and nitrates in Japan, and has developed products such as centrifugal fuel and lube oil separators and pressurised fine filtration systems. MHI says that the combination of MKK’s flue gas scrubbing technology with its own shipbuilding engineering and marketing expertise should ensure the new SOx scrubber system will comply with increasingly stringent marine emission standards. MHI and MKK plan to install one of the new high-performance systems on a ship in a joint study with ClassNK, "K" Line and Japan Marine United Corporation as part of ClassNK's Joint R&D for Industry programme.

This article was originally published by The Motorship.

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Mitsubishi Heavy Industries Marine Machinery & Engine Co

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