Chementator Briefs

Scrubbing ship’s SOx

Mitsubishi Heavy Industries, Ltd. (MHI; Tokyo, Japan; www.mhi.com) and Mitsubishi Hitachi Power Systems, Ltd. (MHPS; Yokohama, Japan; www.mhps.com) have jointly developed a large-scale, rectangular marine scrubber that efficiently removes oxides of sulfur (SOx) from the exhaust gases emitted by marine diesel engines.

The new SOx scrubber uses seawater as its cleaning agent, adopting a simple “open-loop” system in which seawater intake is sprayed directly on the exhaust gas. Effective use of seawater alkaline eliminates the need for chemicals or additional processing. Further, because the horizontal and vertical dimensions of the rectangular scrubber tower can be freely modified, volume efficiency is higher than previous cylindrical scrubbers, providing space savings. The equipment configuration is simple, allowing easy installation not only in newly commissioned ships, but in retrofitted vessels as well.

The new scrubber was developed in response to stringent new SOx emissions regulations that come into effect globally in 2020. It is able to purify exhaust gas emitted from inexpensive heavy fuel oil to a level equivalent to more expensive low-sulfur fuels.