Scrubbers: Closing the loop; Activity 3. Task 1; Air emission measurements.

An SO2 scrubber is fitted in the exhaust channel in order to reduce SO2 emissions to levels corresponding to the combustion of 0.1% sulphur fuel or lower, as described by the MARPOL Annex VI Regulation 14 on sulphur content in marine fuels used for operations in a SECA.

This report covers two emission measurement campaigns. One set of trials contains benchmark measurements for emissions from operations on low sulphur fuel oil. The second set of trials is conducted after the fitting of an exhaust gas cleaning system on the ship. We compare emissions from LSFO combustion with HFO combustion downstream a scrubber. Both are alternatives that can be used to comply with the existing regulations in the area. We also analyse emission reductions over the scrubber, as measurements were conducted both upstream and downstream the installation.

Our results show that the emissions of sulphur dioxide to air are lower when using high sulphur fuel together with a closed loop scrubber than when a low sulphur fuel oil is used. However, the study also concludes that other important air emissions, apart from sulphur dioxide, are at higher levels than emissions from a low sulphur fuel.