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Finnish manufacturer Wärtsilä has said that the recently awarded certification of its marine scrubbers is an important recognition of the company's 'intensive and long lasting development work'.

As previously reported by Bunker Index (article 09 Sep 2009: DNV certifies first SOx exhaust gas scrubber) Norwegian classification society Det Norske Veritas (DNV) recently issued a compliance certificate for a ship fitted with an exhaust gas cleaning system capable of meeting the requirements of SOx Emission Control Areas.

In a statement, Wärtsilä confirmed that its sulphur oxides (SOx) scrubber had been granted the Sulphur Emission Control Area (SECA) Compliance Certificate after performing successfully in a series of tests. A scrubber is an after treatment technology for cleaning exhaust gases of sulphuric oxides. Wärtsilä's solution is the first ever marine scrubber to be awarded this certification.

Prior to the successful Wärtsilä tests, 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 been questioned. Commenting on the issue, Arnauld Filancia, Director of Marketing at Services, Wärtsilä Corporation, said "This certification demonstrates very clearly that the Wärtsilä scrubbing technology works well and is an efficient solution in marine applications. We constantly seek, support and combine technologies that offer our customers similar environmental and economic benefits."

The full-size SOx scrubber test plant was installed on board the 'MS Suula', and was used to clean the exhaust gases from the ship's 4-cylinder in-line Wärtsilä 20 auxiliary diesel engine. This Neste Oil-owned, Finnish registered product tanker operates mainly in the SECA Baltic Sea area, where regulations governing sulphuric oxide emissions are very stringent.

The tests were performed with both high sulphur (3.4%) and low sulphur (1.5%) heavy fuel oil, and verified that the Wärtsilä scrubber system efficiently removes SOx from the exhaust gases.

The measurements, which were part of the certification process and made by an accredited independent body, demonstrated a sulphur dioxide removal efficiency exceeding 99% in all operating conditions, even when using high sulphur fuel. This high level of efficiency was consistent throughout the load range and with all fuels. The efficiency of nitrogen oxides removal was 3-7%. The removal of particulate matter was in the range of 30-60%. The approvals covered also the safety of the installation, as well as the performance.

The International Maritime Organisation (IMO) as well as other regulating bodies will gradually limit the sulphur content in marine fuels. The most common fuels used in marine diesel engines are heavy fuel oils with sulphur contents typically of 1.5 to 3.5 per cent. Such engines can readily burn low-sulphur fuel oils as well, though the associated problems are known and suitable operating guidance is available. Scrubbing exhaust gases is an environmentally friendly and cost-effective alternative for reducing sulphur oxide emissions down to 0.1%.

"The certification demonstrates the technological excellence of Wärtsilä's exhaust gas scrubbers. The Wärtsilä SOx scrubber system complies with the new IMO Guidelines, adopted in July 2009, for cleaning the exhaust emissions from all 2- and 4-stroke engines, including main and auxiliary engines, as well as from oil-fired boilers, in retrofits and newbuilding ships," Wärtsilä said in a statement.

The recognition of Wärtsilä's marine exhausts scrubber system represents the culmination of a project, initiated by Wärtsilä in 2005, to identify feasible solutions and to investigate exhaust gas scrubbing as an alternative to the use of low sulphur fuels.

Wärtsilä offers a wide range of solutions for emissions reduction, and the company aims to be a significant supplier of exhaust gas cleaning technology, fulfilling the requirements being set by increasingly stringent environmental legislation.