19 January 2011
Wärtsilä announced an order from Containerships Ltd Oy to retrofit a Wärtsilä fresh water scrubber for the vessel Containerships VII equipped with a Wärtsilä W7L64 main engine. This is Wärtsilä’s first commercial marine scrubber project for a main engine. The scrubber will be delivered in August 2011.
The conversion will enable the vessel to meet future sulfur oxides (SOx) emission requirements in IMO Sulfur Emission Control Areas (SECA). Scrubbing is a potentially attractive means of meeting the IMO and EU regulations. Scrubbers—which effectively reduce exhaust emissions of SOx and, to some degree, PM—can be used in lieu of low sulfur fuels in IMO-designated SECAs. Therefore, scrubber-equipped ships that operate in SECAs could continue to use the less expensive, high sulfur heavy fuel oils.
Wärtsilä—who gained experience developing scrubbers for stationary diesel power plants—was the first manufacturer awarded a marine scrubber certificate by the classification societies Det Norske Veritas and Germanischer Lloyd. The Wärtsilä scrubber works with fresh water in a closed-loop system in which sulfur oxides are neutralized with sodium hydroxide. A small stream of the scrubbing water is redirected to an onboard treatment unit to remove contaminants. In a “zero discharge” mode, the clean effluents are collected in a holding tank for scheduled, periodical discharge. Contaminants are always disposed of at reception facilities in port. The system complies with the IMO guidelines for cleaning of exhaust emissions from 2- and 4-stroke engines and oil-fired boilers [IMO Resolution MEPC.184(59)].
Exhaust scrubbers are being developed by a number of other marine engine makers and sub-system suppliers. A scrubber developed by Aalborg Industries—in cooperation with MAN Diesel and other partners—was installed onboard Tor Ficaria in May 1010.
Another scrubber application actively developed by marine engine manufacturers is the high pressure scrubber used in exhaust gas recirculation technology. This type of scrubber would purify the recirculated exhaust gas to enable the use of EGR on IMO Tier III (2016) marine diesel engines.