zoom Dutch ship owner and operator Royal Wagenborg has ordered Wärtsilä scrubber systems to clean the exhaust emissions from two of its RoRo carriers, the Balticborg and Bothniaborg. By installing Wärtsilä scrubber systems, the vessels will comply with the regulations covering emissions of sulphur oxides (SOx) while using conventional residual marine fuel (HFO).The Balticborg and Bothniaborg are employed on a long term freight contract with Smurfit Kappa for the weekly shipment of paper products between Haraholmen, Bremen, Sheerness and Terneuzen. These operating routes fall within the Baltic and North Seas’ Sulphur Emission Control Areas (SECA). The retrofitting of these systems will take place in the autumn of this year.The systems chosen for these vessels are Wärtsilä Hybrid Scrubbers, which enable the use of either closed or open loop technology to remove SOx from the exhaust. When operating in open loop mode, exhaust gases enter the system and are sprayed with seawater. The sulphur oxides in the exhaust react with the water to form sulphuric acid. Chemicals are not required since the natural alkalinity of seawater neutralizes the acid.When operating in closed loop mode, the natural alkalinity of seawater is boosted by an alkali. The hybrid approach enables operation in closed loop mode when required, for instance whilst in port and during manoeuvring using NaOH as a buffer. When at sea, the switch can be made to open loop using only seawater.