Measurements of abatement of particles and exhaust gases in a marine gas scrubber

Measurements of exhaust gases from a marine engine equipped with an open-loop wet scrubber using seawater for sulphur dioxide (SO2) abatement are reported. The scrubber reduces the SO2 emissions effectively to levels corresponding to <0.1% S in the fuel (the level that applies to sulphur emission control areas from 2015). The scrubber also reduces the emissions of particulate matter by mass by 75%. The impact on the number of particles is studied for the total particle number and the solid fraction. The total number of particles is reduced by about 92% and the solid fraction by 48% in the scrubber indicating most effective abatement of volatile particles. Also, the content of polycyclic aromatic compounds in the exhaust is significantly reduced by the scrubber. The captured SO2 gives a low pH and high sulphate content in the scrubber water. The reduction in particulate matter is of the same order as what is obtained with a fuel switch from heavy fuel oil to marine gas oil.