With more stringent IMO and EU regulations, SOx-scrubbing is an increasingly attractive way of minimising operational costs by using HFO in an environmentally friendly way.
In SOx Emission Control Areas the cost saving is immediate. The savings will increase in July 2010 when the price premium for low-sulphur fuel is expected to rise. In 2015, when the limit of sulphur in fuel is decreased to 0,1% in SECA areas, the cost savings will be dramatic,with ROI often below one year.
In global operation outside SECAs drastic savings are evident in 2020. Already from 2012 savings are possible when using cheaper HFO with higher sulphur content than the global limit 3.5 %, where available. In EU ports significant savings can be achieved from 1.1.2010 with scrubbers for diesel-generators and oil-fired boilers.
All these savings apply to all ships regardless of age.
Wärtsilä is since 2005 developing and testing a scrubbing plant for removing sulphur oxides (SOx) from the exhaust gases of marine diesel engines and oil-fired boilers. The aim is to develop a competitive and effective product for all marine customers.
Within the project, the following features have all been investigated and solid marine integrated solutions engineered: scrubber design, performance, lifetime and economy, corrosion, scaling, the effect of scrubbing equipment on engine performance, installation requirements, discharge water criteria, ecological impact, sludge handling, exhaust plume quality, noise, chemicals and certification requirements. The Wärtsilä scrubber system has been designed according to IMO Resolution MEPC.184(59, July 2009, Guidelines for Exhaust Gas Cleaning Systems.
The scrubber has been tested during 2008-2009 on a Wärtsilä 4L20 auxiliary engine on-board a tanker. The testing has been successful and the Wärtsilä scrubber has been certified by DNV and GL.
Safe for the environment
The chosen technology is a closed-loop fresh water scrubber to which NaOH is added in order to neutralize SOx emissions. The closed-loop system features cleaning of the small bleed-off extracted from the loop, and thereby fulfils all quality and monitoring requirements stipulated by the IMO. Clean effluents can safely be discharged overboard with no harm to the environment. If operation in zero discharge mode is requested, the effluent can be led to a holding tank for scheduled and periodical discharge.
Documentation already in place
The documentation as per marine industry standards is at an advanced stage and Wärtsilä's scrubber system documentations have been approved by the classification societies. Based on the documentation, comprised of the EGC – Sox Technical Manual (ETM), on-board monitoring manual (OMM) and Record book form, and on the verified performance of the scrubber, a SCC (SECA compliance certificate) has been granted. Wärtsilä has also developed a scrubber safety concept in order to be able to identify and eliminated possible risks in operation of the scrubber.
Wärtsilä first to get certificate for marine SOx scrubber
The use of scrubbers as an efficient and cost-effective alternative to the use of low sulphur fuel for reducing SOx emissions from ships, had earlier been questioned. However, this certification demonstrates very clearly that this technology works well for marine installations. Wärtsilä continuously seeks, supports, and combines technologies that offer its customers similar environmental and economic benefits. “These certificates bring the final stone to the demonstration that this technology works well for marine installation. We are continuously working with customer who are convinced of the environmental and economic benefits of our scrubbing solution and engineering integration.” says Arnauld Filancia, Director, Marketing at Wärtsilä Corporation, Services.
The Wärtsilä SOx scrubber system complies with the new IMO guidelines for cleaning the exhaust emissions from all 2- and 4-stroke engines and oil-fired boilers, in retrofit and newbuilding ships.
