Characterization of a method for aerosol generation from heavy fuel oil (HFO) as an alternative to emissions from ship diesel engines

This work describes a laboratory method to synthesize aerosols with properties similar to those emitted by ocean going ships. In this method, an oxy-hydrogen flame burner nebulizes and combusts heavy fuel oil (HFO). The oil was fed to the burner via a syringe pump at a maximum rate of 15 ml/h. Adjusting the feed temperature of the oil and the use of a quenching ring in the burner, it is possible to obtain an aerosol with a mode diameter of about 11 nm. This is close to the reported 5-8 nm for the nano-mode of ship emissions. Filter samples were also analyzed for elemental carbon, organic carbon and anion composition. No elemental carbon mass was detected and only a few sulfur containing compounds were present. A chemical equilibrium model was applied for both oxy-hydrogen flame and 2-stroke ship diesel engine combustion conditions to predict equilibrium concentrations, chemical formula and phase of vanadium and nickel containing compounds. The model confirmed that the real-world ship diesel engine and the oxy-hydrogen flame burner combustion processes produced the same vanadium, nickel and sulfur particulate matter (PM) products in terms of chemical formula and phase. Both the 5-8 nm particles from real-world ship emissions and the laboratory synthesized particles contain transition metals. Transmission electron microscope (TEM) images of laboratory synthesized particles show similar morphology to those sampled from a ship. Cloud condensation nuclei (CCN) measurement indicates that neither laboratory generated nor ship emitted aerosol is hygroscopic. To our knowledge, this is the first time the 5-8 nm particles emitted from ships have been aptly synthesized on a laboratory scale. (C) 2010 Elsevier Ltd. All rights reserved.